WO2021186629A1

WO2021186629A1 - Circuit sheet, circuit board, and method for manufacturing circuit board

Info

Publication number: WO2021186629A1
Application number: PCT/JP2020/012054
Authority: WO
Inventors: 光生戸川; 大地酒井; 寿行高岩; 一司皆川; 岳人野村; 卓士齋藤; 加奈子石原; 富生小川; 健太郎大倉; 洋別井; 輝之塚田; 早苗武田; 朗宏石毛
Original assignee: 昭和電工マテリアルズ株式会社
Priority date: 2020-03-18
Filing date: 2020-03-18
Publication date: 2021-09-23

Abstract

Provided is a circuit sheet that is provided with a circuit (1) which is formed from a conductor and an insulating part (2) which is provided in spaces in the circuit (1), wherein a step (3) is provided to the side surface of the circuit between an element mounting surface and the reverse surface to the element mounting surface, and the step (3) is covered by the insulating part (2). The area of portions where the circuit and insulating part are in contact is increased and thus makes separation of the circuit and insulating part unlikely to occur, so as to provide a circuit sheet having excellent reliability in which separation between the side surface of the circuit and the insulating part is unlikely to occur, which prevents air bubbles being trapped in such areas of separation, and which prevents decreased insulation resistance.

Description

Circuit sheet, circuit board and circuit board manufacturing method

This disclosure relates to a circuit sheet, a circuit board, and a method for manufacturing a circuit board.

With the progress of miniaturization and high functionality of electronic devices, printed circuit boards are widely used as circuit boards capable of mounting elements at high density on the boards. A printed circuit board is generally manufactured by attaching a metal foil to the substrate, etching the printed circuit board, and processing the printed circuit board into a desired circuit shape.

On the other hand, with the diversification of the usage environment of electronic devices, it is required to increase the current capacity of the circuit board (increase the current). The current capacity of the circuit board can be increased by increasing the cross-sectional area of the circuit (that is, increasing the thickness of the circuit).

As a method of manufacturing a circuit board corresponding to a large current, a method of using a circuit formed by processing a metal plate has been proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2-137392

In the method described in Patent Document 1, after processing a metal plate into a circuit, a state (circuit sheet) in which a space between circuits is filled with resin to form an insulating portion is produced, and an element is mounted on the circuit. , A circuit package is manufactured by sealing the periphery with an insulating material.

In the circuit sheet manufactured by the above method, heat treatment of the circuit sheet, crimping in the process of manufacturing the circuit board, etc. are performed, so that peeling is likely to occur between the side surface of the circuit and the insulating portion, and at the peeled portion. , The reliability may be impaired by trapping air bubbles or lowering the insulation resistance. Further, when the circuit sheet is sealed with a silicon gel or the like in a later step, air bubbles may be generated from the peeled portion on the side surface of the circuit, which may reduce the insulation resistance.

In view of the above circumstances, one aspect of the present disclosure is to provide a circuit sheet having excellent reliability, a circuit board including the circuit sheet, and a method for manufacturing the same.

Specific means for providing the above tasks include the following embodiments.
<1A> A circuit made of a conductor and an insulating portion provided in a space between the circuits are provided, and the side surface between the element mounting surface and the surface opposite to the element mounting surface in the circuit has a step. A circuit sheet having the step and having the step covered with the insulating portion.
<2A> The circuit sheet according to <1A>, wherein the step has a surface parallel to at least one of the element mounting surface and the surface opposite to the element mounting surface.
<3A> The circuit sheet according to <1A> or <2A>, wherein the circuit has a region in which the cross-sectional shape of the circuit in the thickness direction of the circuit is substantially T-shaped.
<4A> The circuit sheet according to any one of <1A> to <3A>, wherein the step is provided on the outer periphery of the circuit when viewed in the thickness direction of the circuit.
<5A> When viewed in the thickness direction of the circuit, the step is provided inside the circuit, and the insulating portion provided in the space inside the circuit is located in the outer space of the circuit. The circuit sheet according to any one of <1A> to <4A>, which is connected to the insulating portion provided at two or more locations.
<6A> The surface roughness of the side surface is any one of <1A> to <5A>, which is larger than at least one of the surface roughness of the element mounting surface and the surface roughness of the surface opposite to the element mounting surface. The circuit sheet described in.
<7A> The circuit sheet according to any one of <1A> to <6A>, an insulating layer arranged so as to be in contact with a surface opposite to the element mounting surface, and an insulating layer arranged so as to be in contact with the insulating layer. A circuit board having heat-dissipating members in this order.
<8A> Lamination of the circuit sheet according to any one of <1A> to <6A>, an insulating layer arranged on the surface opposite to the element mounting surface, and a heat radiating member arranged in this order. A method for manufacturing a circuit board, which comprises a step of pressurizing a body in the thickness direction.

<1B> An insulation composed of a conductor and having a first surface and a second surface located on the opposite side of the first surface and an insulation arranged so as to be in contact with the second surface of the circuit. A layer and a heat radiating member arranged so as to be in contact with the insulating layer are provided in this order in the thickness direction.
A circuit board having a region in which the outer peripheral edge portion of the first surface and the outer peripheral edge portion of the second surface do not overlap in a plan view from the circuit side.
<2B> The circuit board according to <1B>, wherein the thickness of the circuit is more than 120 μm.
<3B> The circuit board according to <1B> or <2B>, wherein the heat radiating member has a thickness of more than 120 μm.
<4B> Any one of <1B> to <3B> in which the ratio of the thickness of the circuit to the thickness of the heat radiating member (circuit thickness / average thickness of the heat radiating member) is 0.2 to 25. The circuit board described in 1.
<5B> The circuit board according to <4B>, wherein the ratio of the thickness of the circuit to the thickness of the heat radiating member is 1 to 25.
<6B> The circuit board according to any one of <1B> to <5B>, wherein the partial discharge start voltage of the insulating layer is 1.0 kV or more.
<7B> The circuit board according to any one of <1B> to <6B>, wherein the dielectric breakdown voltage between the heat radiating member and the circuit is 1.5 kV or more.
<8B> In a plan view from the circuit side, the entire outer peripheral edge portion of the first surface does not overlap with the outer peripheral edge portion of the second surface to any one of <1B> to <7B>. The circuit board described.
<9B> The circuit board according to <8B>, wherein the shortest distance between the outer peripheral edge portion of the first surface and the outer peripheral edge portion of the second surface is 0.01 mm or more and less than 1.0 mm.
<10B> The circuit board according to any one of <1B> to <9B>, wherein the area of the surface of the heat radiating member on the insulating layer side is larger than the area of the second surface of the circuit.
<11B> Provided in at least one of a circuit composed of a conductor and having a first surface and a second surface located on the opposite side of the first surface, a space between the circuits, and the periphery of the circuit. With an insulating part,
A circuit sheet having a region in which the outer peripheral edge portion of the first surface and the outer peripheral edge portion of the second surface do not overlap in a plan view.
<12B> The laminated body in which the circuit sheet according to <11B>, the insulating layer arranged so as to be in contact with the second surface, and the heat radiating member are arranged in this order in the thickness direction is arranged in the thickness direction. A method of manufacturing a circuit board having a step of pressurizing.
<13B> A method for manufacturing a circuit board for manufacturing the circuit board according to any one of <1B> to <10B>.
The circuit, the insulating layer arranged so as to be in contact with the second surface of the circuit, and the heat radiating member arranged so as to be in contact with the insulating layer are laminated in this order in the thickness direction. A method for manufacturing a circuit board, which comprises a step of pressurizing a body in the thickness direction.

<1C> In all combinations of two or more circuits made of conductors, which are independent of each other and adjacent to each other, the circuits are independent of each other when viewed from the element mounting surface of the circuit. A circuit sheet in which a highly elastic member is located on a straight line in an arbitrary direction that passes between two adjacent circuits and is parallel to the element mounting surface.
<2C> The circuit sheet according to <1C>, wherein the highly elastic member is the circuit.
<3C> The circuit sheet according to <1C> or <2C>, further comprising an insulating portion provided at least a part between the two or more circuits.
<4C> The circuit sheet according to <3C>, wherein the insulating portion is provided so that the element mounting surface of the circuit and the surface opposite to the element mounting surface are exposed.
<5C> The circuit sheet according to <3C> or <4C>, wherein the thickness of the insulating portion with respect to the thickness of the circuit is 0.9 or more.
<6C> The method according to any one of <1C> to <5C>, which is arranged on the surface opposite to the element mounting surface of the circuit and further includes an insulating layer that holds the relative arrangement of the two or more circuits. Circuit sheet.
<7C> The circuit sheet according to any one of <1C> to <5C>, the insulating layer arranged so as to be in contact with the surface opposite to the element mounting surface of the circuit sheet, and the insulating layer so as to be in contact with the insulating layer. A circuit board having heat-dissipating members arranged in this order.
<8C> A circuit board having the circuit sheet according to <6C> and a heat radiating member arranged so as to be in contact with the insulating layer.
<9C> The circuit sheet according to any one of <1C> to <5C>, the insulating layer arranged on the surface opposite to the element mounting surface of the circuit sheet, and the heat radiating member are arranged in this order. The thickness of the laminated body in the state, or the laminated body in which the circuit sheet according to <6C> and the heat radiating member are arranged so that the heat radiating member is located on the insulating layer side of the circuit sheet. A method of manufacturing a circuit board, which comprises a step of pressurizing in a direction.

<1D> A circuit sheet comprising a circuit and an insulating portion provided in a space between the circuits, and the insulating portion is recessed on an element mounting surface.
<2D> With multiple circuits
The circuit is provided between the plurality of circuits so that at least a part of the element mounting surface on which the element is mounted and at least a part of the surface opposite to the element mounting surface are exposed. It has an insulating part that holds the relative positions of a plurality of circuits, and has.
A circuit sheet in which the surface of the insulating portion on the element mounting surface side is recessed with respect to the element mounting surface of the circuit.
<3D> The circuit sheet according to <1D> or <2D>, wherein the surface opposite to the element mounting surface is flatter than the element mounting surface.
<4D> The circuit sheet according to any one of <1D> to <3D>, wherein the surface opposite to the element mounting surface is a surface on which an insulating layer and a heat radiating member are arranged.
<5D> The circuit sheet according to any one of <1D> to <4D>, which has a portion where the circuit and the insulating portion overlap in the thickness direction on a surface opposite to the element mounting surface.
<6D> A step of filling an insulating material between the circuits with a protective film attached to one surface of the sheet-shaped circuit and a step of curing the insulating material are provided in this order.
A method for manufacturing a circuit sheet, wherein the protective film is deformable with volume shrinkage due to curing of the insulating material.
<7D> The step of filling the insulating material and the step of curing the insulating material do not deform on the surface of the circuit opposite to the surface to which the protective film is attached due to volume shrinkage due to the curing of the insulating material. The method for manufacturing a circuit sheet according to <6D>, which is performed in a state where the members are in contact with each other.
<8D> The circuit sheet according to <6D> or <7D>, wherein the cured product of the insulating material obtained in the step of curing the insulating material is in a recessed state on the surface of the circuit to which the protective film is attached. Manufacturing method.
<9D> The circuit sheet according to any one of <1D> to <5D>, the insulating layer arranged so as to be in contact with the surface opposite to the element mounting surface of the circuit sheet, and the insulating layer so as to be in contact with the insulating layer. A circuit board having a heat radiating member arranged in.
<10D> The circuit sheet according to any one of <1D> to <5D>, the insulating layer arranged on the surface opposite to the element mounting surface of the circuit sheet, and the heat radiating member are arranged in this order. It has a step of pressurizing the laminated body in the state,
A method for manufacturing a circuit board, wherein the pressurization is performed in a state where a cushion material deformable by the pressurization is arranged on an element mounting surface of the circuit sheet.

<1E> A circuit and an insulating portion provided between the circuits are provided, and the surface roughness A of at least a part of the surface of the circuit in contact with the insulating portion is the surface roughness B of the element mounting surface of the circuit. Larger, circuit sheet.
<2E> Of the surfaces in contact with the insulating portion of the circuit, the surface roughness A of at least the portion connected to the surface opposite to the element mounting surface of the circuit is larger than the surface roughness B of the element mounting surface of the circuit. The circuit sheet according to <1E>.
<3E> The circuit sheet according to <1E> or <2E>, wherein the surface roughness C of the surface opposite to the element mounting surface of the circuit is larger than the surface roughness B of the element mounting surface of the circuit.
<4E> The circuit sheet according to any one of <1E> to <3E>, further comprising an insulating layer provided on a surface opposite to the element mounting surface of the circuit.
<5E> The circuit sheet according to <4E>, wherein the insulating portion and the insulating layer are different members.
<6E> The circuit sheet according to <4E>, wherein the insulating portion and the insulating layer are the same member.
<7E> The circuit sheet according to any one of <1E> to <6E>, wherein the element mounting surface of the circuit is coated with a plated metal.
<8E> The surface roughness A expressed by the arithmetic mean roughness Ra is 0.3 μm or more, and the surface roughness B expressed by the arithmetic average roughness Ra is less than 0.3 μm, <1E>. The circuit sheet according to any one of <7E>.
<9E> The circuit sheet according to any one of <1E> to <8E>, wherein the surface roughness A expressed by the arithmetic mean roughness Ra is 0.6 μm or more.
<10E> A step of roughening the surface of the circuit with a protective member attached to one surface of the sheet-shaped circuit and a step of forming an insulating portion between the circuits are included in this order. The method for manufacturing a circuit sheet according to any one of 1E> to <9E>.
<11E> The circuit sheet according to <10E>, wherein the roughening is performed on a portion of the circuit in contact with the insulating portion and a surface of the circuit opposite to the surface to which the protective member is attached. Production method.
<12E> The method for manufacturing a circuit sheet according to <10E> or <11E>, further comprising a step of arranging an insulating layer on a surface opposite to the surface to which the protective member of the circuit is attached.
<13E> The method for manufacturing a circuit sheet according to <12E>, wherein the step of arranging the insulating layer is performed after the step of forming the insulating portion.
<14E> The method for manufacturing a circuit sheet according to <12E>, wherein the step of arranging the insulating layer is performed at the same time as the step of forming the insulating portion.
<15E> A circuit board having the circuit sheet according to any one of <1E> to <9E> and a heat radiating member arranged on a surface opposite to the element mounting surface of the circuit sheet.
<16E> A laminated body in which the circuit sheet according to any one of <1E> to <9E> and the heat radiating member arranged on the surface opposite to the element mounting surface of the circuit sheet are arranged in this order. A method of manufacturing a circuit board, which comprises a step of pressurizing.

<1F> A circuit sheet with a case including a circuit sheet including a circuit and an insulating portion provided between the circuits, and a case arranged on a heating element mounting surface of the circuit sheet.
<2F> The circuit sheet with a case according to <1F>, further comprising a heating element arranged on the circuit on the heating element mounting surface.
<3F> A plurality of circuits are provided, and the insulating portion is provided between the plurality of circuits. In the circuit, at least a part of a heating element mounting surface on which a heating element is mounted and the heating element mounting surface. The circuit sheet with a case according to <1F> or <2F>, which holds the relative positions of the plurality of circuits so that at least a part of the surface opposite to the one is exposed.
<4F> A circuit sheet including a circuit and an insulating portion provided between the circuits, a case arranged on the heating element mounting surface of the circuit sheet, a heating element arranged on the circuit, and the above. A circuit package that includes a sealing part that is placed in a portion surrounded by a case.
<5F> A circuit board having the circuit package according to <4F>, an insulating layer and a heat radiating member arranged on the side opposite to the heating element mounting surface of the circuit sheet.
<6F> The circuit board according to <5F>, wherein one surface of the circuit is in contact with the heating element and the other surface is in contact with the insulating layer.
<7F> The step of forming a sealing portion in the portion of the circuit sheet with a case described in any one of <1F> to <3F> surrounded by the case.
A method for manufacturing a circuit board, comprising a step of arranging an insulating layer and a heat radiating member on the surface opposite to the heating element mounting surface of the circuit sheet with a case.
<8F> A method for manufacturing a circuit board, which includes the following steps (1) to (4). However, step (2) is performed before step (3) and step (4), and step (1) is performed before step (3).
(1) Step of installing the case on the heating element mounting surface of the circuit sheet (2) Step of mounting the heating element on the circuit of the circuit sheet (3) Surrounded by the case on the heating element mounting surface of the circuit sheet Step of forming a sealing part in the portion (4) Step of arranging an insulating layer and a heat radiating member on the surface opposite to the heating element mounting surface of the circuit sheet.

<1G> A circuit board having a circuit, an insulating layer, and a base substrate having a surface larger than the element mounting surface of the circuit and having a surface on which the circuit is arranged via the insulating layer in this order. It is a manufacturing method of the circuit board to be manufactured.
A laminate in which the circuit, the insulating layer, and the base substrate are arranged in this order is prepared, and a spacer member having substantially the same thickness as the total thickness of the circuit and the insulating layer is provided on the side surface of the circuit and the insulating layer. A method for manufacturing a circuit board, which comprises a step of pressurizing the laminate in a state of being arranged on the base substrate so as to be in contact with at least a part of the periphery of the circuit board.
<2G> A method for manufacturing a circuit board that manufactures a circuit board having a circuit, an insulating layer, and a base board in this order.
A laminate in which the circuit, the insulating layer, and the base substrate are arranged in this order is prepared, and a spacer member having substantially the same thickness as the total thickness of the circuit, the insulating layer, and the base substrate is provided in the laminate. A method for manufacturing a circuit board, which comprises a step of pressurizing the laminated body in a state of being arranged on the same plane as the laminated body so as to be in contact with at least a part of the periphery of a side surface.
<3G> The method for manufacturing a circuit board according to <1G>, further comprising a step of aligning the circuit and the insulating layer on the base substrate using the spacer member before pressurizing the laminate.
<4G> The circuit according to <1G> or <3G>, wherein in the pressurizing step, the spacer member is in contact with at least two regions around the spacer and is arranged so as to sandwich the circuit and the insulating layer. Substrate manufacturing method.
<5G> The method for manufacturing a circuit board according to <2G>, wherein in the pressurizing step, the spacer member is in contact with at least two regions around the spacer and is arranged so as to sandwich the laminate.
<6G> Described in any one of <1G> to <5G>, wherein the thickness of the spacer member is equal to or less than the total thickness, and the difference between the thickness of the spacer member and the total thickness is 0 μm to 250 μm. Circuit board manufacturing method.
<7G> The circuit has a circuit portion and a space other than the circuit portion, and an insulating portion is provided in at least a part of the space before being arranged on the insulating layer and the base substrate. The method for manufacturing a circuit board according to any one of <1G> to <5G>, wherein the circuit is exposed on the element mounting surface and the surface opposite to the element mounting surface.

<1H> The circuit, the insulating layer, and the heat radiating member are laminated in this order.
The average thickness of the circuit is 500 μm or more.
A circuit board having an average thickness of the insulating layer of 120 μm or more.
<2H> The circuit board according to <1H>, wherein the average thickness of the insulating layer exceeds 200 μm.
<3H> The circuit board according to <1H> or <2H>, wherein the heat dissipation member has an average thickness of 100 μm or more.
<4H> The circuit board according to any one of <1H> to <3H>, wherein the thermal conductivity of the insulating layer is 6 W / (m · K) or more.
<5H> The circuit board according to any one of <1H> to <4H>, wherein the glass transition temperature of the insulating resin layer is 170 ° C. or higher.
<6H> The circuit board according to any one of <1H> to <5H>, wherein the total average thickness of the circuit and the heat radiating member is 600 μm or more.
<7H> The circuit according to any one of <1H> to <6H>, wherein the ratio of the average thickness of the circuit to the average thickness of the heat radiating member (circuit / heat radiating member) is 1.0 to 30. substrate.
<8H> The circuit board according to any one of <1H> to <7H>, wherein the surface roughness (Ra) of the circuit on the side facing the insulating resin layer is 0.5 μm or more.
<9H> The circuit board according to any one of <1H> to <8H>, wherein the surface roughness (Ra) of the circuit on the side opposite to the side facing the insulating resin layer is less than 0.2 μm.
<10H> The circuit board according to any one of <1H> to <9H>, wherein the surface roughness (Ra) of the heat radiating member on the side facing the insulating resin layer is 0.5 μm or more.
<11H> The circuit board according to any one of <1H> to <10H>, wherein the surface roughness (Ra) of the heat radiating member on the side opposite to the side facing the insulating resin layer is less than 0.2 μm. ..
<12H> One of <1H> to <11H> in which the surface area of the circuit opposite to the side facing the insulating resin layer is larger than the surface area of the circuit facing the insulating resin layer. The circuit board described.
<13H> The circuit board according to any one of <1H> to <12H>, wherein the coefficient of thermal expansion of the circuit and the coefficient of thermal expansion of the heat radiating member are different.
<14H> The circuit board according to any one of <1H> to <12H>, wherein the coefficient of thermal expansion of the circuit and the coefficient of thermal expansion of the heat radiating member are the same.
<15H> The circuit board according to any one of <1H> to <14H>, wherein the breaking voltage between the circuit and the heat radiating member is 2.5 kV or more.
<16H> The circuit board according to any one of <1H> to <15H>, wherein the partial discharge start voltage between the circuit and the heat radiating member is 2.5 kV or more.
<17H> A semiconductor device including the circuit board according to any one of <1H> to <16H> and a semiconductor element.

<1I> With multiple circuits
The circuit is provided between the plurality of circuits so that at least a part of the element mounting surface on which the element is mounted and at least a part of the surface opposite to the element mounting surface are exposed. It has an insulating part that holds the relative positions of a plurality of circuits, and has.
A circuit sheet in which the surface of the insulating portion on the side opposite to the element mounting surface is recessed toward the element mounting surface side with respect to the surface of the circuit opposite to the element mounting surface.
<2I> The circuit sheet according to <1I>, wherein the maximum value of the distance between the surface of the insulating portion and the surface of the circuit opposite to the element mounting surface is 20 μm or less.
<3I> Arranged so as to be in contact with the circuit sheet according to <1I> or <2I>, the surface of the insulating portion on the side opposite to the element mounting surface, and the surface of the circuit opposite to the element mounting surface. A circuit board having an insulating layer to be formed and a heat radiating member arranged so as to be in contact with the insulating layer.
<4I> Pressurize the laminated body in which the circuit sheet according to any one of <1I> to <3I>, the insulating layer arranged on the connection surface side, and the heat radiating member are arranged in this order. A method of manufacturing a circuit board having a process.
<1J> With multiple circuits
The plurality of circuits are provided between the plurality of circuits so that at least a part of the heating element mounting surface and at least a part of the surface opposite to the heating element mounting surface are exposed in the circuit. Has an insulating part that holds the relative position of
A circuit sheet in which the height variation of the surface opposite to the heating element mounting surface in the circuit is 40 μm or less per 10 mm in the plane direction.
<2J> An insulating layer arranged so as to be in contact with the circuit sheet according to <1J>, the surface of the insulating portion on the side opposite to the element mounting surface, and the surface of the circuit opposite to the element mounting surface. A circuit board having a heat-dissipating member arranged so as to be in contact with the insulating layer.
<3J> A step of pressurizing a laminate in which the circuit sheet according to <1J> or <2J>, the insulating layer arranged on the side opposite to the element mounting surface, and the heat radiating member are arranged in this order. A method of manufacturing a circuit board having.
<1K> With multiple circuits
The plurality of circuits are provided between the plurality of circuits so that at least a part of the heating element mounting surface and at least a part of the surface opposite to the heating element mounting surface are exposed in the circuit. Has an insulating part that holds the relative position of
A circuit sheet in which the variation in height of the heating element mounting surface of the circuit is 40 μm or less per 10 mm in the plane direction.
<2K> An insulating layer arranged so as to be in contact with the circuit sheet according to <1K>, the surface of the insulating portion on the side opposite to the element mounting surface, and the surface of the circuit opposite to the element mounting surface. A circuit board having a heat-dissipating member arranged so as to be in contact with the insulating layer.
<3K> A step of pressurizing a laminate in which the circuit sheet according to <1K> or <2K>, the insulating layer arranged on the side opposite to the element mounting surface, and the heat radiating member are arranged in this order. A method of manufacturing a circuit board having.

<1L> With multiple circuits
A holding portion provided on one surface side of the plurality of circuits for holding relative positions of the plurality of circuits, and a holding portion.
A case provided on the holding portion and surrounding the plurality of circuits when viewed from one surface side of the circuit, and a case.
Have,
A circuit sheet with a case in which the other side of the plurality of circuits is exposed.
<2L> The circuit sheet with a case according to <1L>, wherein the holding portion is detachable from the plurality of circuits.
<3L> The circuit sheet with a case according to <2L>, wherein at least a part of one surface of the plurality of circuits is a heating element mounting surface on which a heating element is mounted.
<4L> The circuit sheet with a case according to any one of <1L> to <3L>, the insulating layer arranged on the exposed other surface side of the circuit in the circuit sheet with a case, and the heat radiating member. A method for manufacturing a circuit board, which comprises a step of pressurizing a laminate in a state where the above are arranged in this order.
<5L> The holding portion can be separated from the plurality of circuits.
The method for manufacturing a circuit board according to <4L>, further comprising a step of peeling the holding portion from one surface of the plurality of circuits after the step of pressurizing.

According to one aspect of the present disclosure, a circuit sheet having excellent reliability, a circuit board including the circuit sheet, and a method for manufacturing the same are provided.

It is a schematic plan view of the specific example of the circuit sheet of this disclosure when viewed from the element mounting surface. FIG. 1A is a cross-sectional view taken along the line AA of FIG. 1A. It is an enlarged view of FIG. 1B. It is a schematic plan view of the specific example of the conventional circuit sheet when viewed from the element mounting surface. FIG. 5 is a cross-sectional view taken along the line AA of FIG. 1D. It is sectional drawing which shows the schematic structure of the specific example 1 of the circuit board of this disclosure. It is a top view from the circuit side which shows the schematic structure of the specific example 1 of the circuit board of this disclosure. It is sectional drawing which shows the schematic structure of the specific example 2 of the circuit board of this disclosure. It is sectional drawing which shows the schematic structure of the specific example of the conventional circuit board. It is a schematic block diagram of the conventional circuit sheet. It is a schematic block diagram of the circuit sheet of the 3rd Embodiment of this disclosure. It is a schematic block diagram of the circuit sheet of the 4th Embodiment of this disclosure. It is a block diagram of the circuit sheet of Examples 1C-3C. It is a block diagram of the circuit sheet of Examples 4C to 6C. It is a block diagram of the circuit sheet of Examples 7C-9C. It is a block diagram of the circuit sheet of Examples 10C-12C. It is a block diagram of the circuit sheet of Comparative Examples 1C to 3C. It is a block diagram of the circuit sheet of Comparative Examples 4C to 6C. It is a block diagram of the circuit sheet of Comparative Examples 7C-9C. It is a figure which shows schematic cross section of a circuit sheet. It is a figure which shows roughly the part where the circuit and the insulating part overlap in the thickness direction. It is sectional drawing which shows the structure of the circuit sheet schematicly. It is a figure which shows an example of the manufacturing process of the circuit board which uses the circuit sheet with a case of this disclosure. It is a figure which shows an example of the manufacturing process of the circuit board which uses the conventional circuit sheet. It is a schematic block diagram which shows the manufacturing method of the conventional circuit board. It is a schematic block diagram which shows an example of the manufacturing method 1 of a circuit board. It is a schematic block diagram which shows an example of the manufacturing method 2 of a circuit board. It is sectional drawing of the circuit board 220 which is one Embodiment of the circuit board of this disclosure. It is a schematic block diagram of the circuit sheet of this disclosure. It is a schematic block diagram of the circuit sheet of this disclosure. It is a schematic block diagram of the circuit sheet of this disclosure.

Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. The configurations described in each embodiment may be combined as appropriate.
In the following embodiments, the components (including element steps and the like) are not essential unless otherwise specified. The same applies to the numerical values and their ranges, and does not limit the present invention.
In the present disclosure, the term "process" includes not only a process independent of other processes but also the process if the purpose of the process is achieved even if the process cannot be clearly distinguished from the other process. ..
The numerical range indicated by using "-" in the present disclosure includes the numerical values before and after "-" as the minimum value and the maximum value, respectively.
In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. .. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.
In the present disclosure, each component may contain a plurality of applicable substances. When a plurality of substances corresponding to each component are present in the composition, the content or content of each component is the total content or content of the plurality of substances present in the composition unless otherwise specified. Means quantity.
In the present disclosure, the term "layer" is used not only when the area where the layer exists is observed, but also when it is formed only in a part of the area. included.
In the present disclosure, the term "laminated" means stacking layers or members, and two or more layers or members may be combined, or two or more layers or members may be removable.
In the present disclosure, the average thickness of the layer or member is a value given as an arithmetic mean value obtained by measuring the thickness of five points of the target layer or member.
The thickness of the layer or member can be measured using a micrometer or the like.
When the embodiment is described in the present disclosure with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. Further, the size of the members in each figure is conceptual, and the relative relationship between the sizes of the members is not limited to this.
In the present disclosure, "when viewed in the thickness direction of the circuit" means when viewed in the thickness direction of the circuit from the element mounting surface and in the thickness direction of the circuit from the surface opposite to the element mounting surface. Means at least one of the times.
In the present disclosure, "inter-circuit" includes a gap between a specific circuit and another circuit other than the specific circuit, and in one specific circuit.

<Circuit sheet of the first embodiment>
The circuit sheet of the first embodiment of the present disclosure includes a circuit made of a conductor and an insulating portion provided in a space between the circuits, and the element mounting surface in the circuit is opposite to the element mounting surface. The side surface between the surface and the surface has a step, and the step is covered with the insulating portion.

In the circuit sheet of the present disclosure, since the side surface of the circuit has a step and the step is covered with an insulating portion, the area of the portion where the circuit and the insulating portion are in contact with each other becomes large, and the circuit and the insulating portion are separated from each other. Is less likely to occur. Therefore, in the circuit sheet of the present disclosure, when heat treatment of the circuit sheet, crimping in the process of manufacturing the circuit board, etc. are performed, peeling is unlikely to occur between the side surface of the circuit and the insulating portion, and the peeling portion is present. , Trapping of air bubbles and deterioration of insulation resistance are suppressed, and the reliability is excellent.

In particular, when there are a plurality of circuits and a potential difference occurs between adjacent circuits, the insulation resistance of the circuit sheet deteriorates if air bubbles, voids, etc. are generated on or near the side surface of the circuit. , It is important to suppress the peeling from the insulating part. Even in such a case, the circuit sheet of the present disclosure can suitably suppress a decrease in insulation resistance and is excellent in reliability.

When the circuit sheet is provided with a circuit having a large thickness, for example, a thick copper circuit, the circuit and the insulating portion are likely to be separated due to the weight of the circuit itself. On the other hand, in the circuit sheet of the present disclosure, even when the thickness of the circuit is large, the area of the portion where the circuit and the insulating portion are in contact with each other is large, and the circuit and the insulating portion are unlikely to be separated from each other.

The circuit sheet of the present disclosure includes at least one circuit composed of conductors. The material of the circuit is not particularly limited as long as it is a conductor, and examples thereof include metal. Examples of the metal include copper, silver, chromium copper, tungsten copper, nickel, nickel-plated copper, aluminum, and aluminum whose surface is modified to alumite. From the viewpoint of conductivity, the metal preferably contains copper.

The thickness of the circuit is not particularly limited and can be selected according to the application of the circuit sheet and the like. From the viewpoint of increasing the current of the circuit, the thickness of the circuit is preferably 350 μm or more, and from the viewpoint of easily providing a step in the circuit, it is more preferably 400 μm or more. It is more preferably 500 μm or more from the viewpoint of easy holding, and particularly preferably 1000 μm or more from the viewpoint of securing a wide adhesive area between the circuit and the insulating portion and easily suppressing peeling. From the viewpoint of weight reduction and height reduction, the thickness of the circuit may be 5000 μm or less. It is preferably 3000 μm or less from the viewpoint that a step is easily provided in the circuit. When the thickness of the circuit is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.
When a part of the circuit is embedded in a member adjacent to the circuit sheet such as an insulating layer, the thickness of the embedded part is also included in the thickness of the circuit.

The width of the circuit when observing the element mounting surface of the circuit sheet is not particularly limited, and may be selected according to the application of the circuit sheet and the like. For example, the width of the circuit may be 100 μm to 100 mm. When the width of the circuit is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.

The circuit can be obtained, for example, by processing a metal plate into a circuit state having a desired shape. The processing method is not particularly limited, and can be performed by a known method such as punching, cutting, etching, and processing in which they are combined. It is preferable to form the circuit by cutting, etching, or the like from the viewpoint of improving the accuracy in circuit fabrication, the viewpoint that it is easy to process the step, and the like. Etching is more preferable from the viewpoint that the circuit is not easily deformed by machining stress when forming a step.

When the circuit is manufactured by etching, the etching method of the metal plate is not particularly limited. From the viewpoint of facilitating the production of the circuit sheet of the present disclosure, it is preferable to form the circuit by etching from both sides (that is, two main surfaces facing each other) of the metal plate. By processing from both sides, it is easy to form a step, and work efficiency is high. When etching from both sides of the metal plate, both sides may be etched at the same time, or both sides may be etched alternately.

The circuit may be roughened. For example, when the circuit is in contact with an insulating layer described later, if the surface in contact with the insulating layer is at least roughened, it is possible to obtain a state in which the circuit can be sufficiently adhered to the insulating layer while suppressing the generation of voids. Specifically, it is considered that the adhesion due to the Van der Waals force can be improved by roughening the surface in contact with the insulating layer of the circuit to improve the pull-out force due to the anchor effect or increase the adhesion area.

The method of roughening the circuit is not particularly limited, and it may be performed by a physical method or a chemical method. For example, when the material of the circuit is copper, the physical method includes sanding, sandblasting, laser irradiation, milling and the like. Examples of the chemical method include a magdamit treatment, a CZ treatment, a blackening treatment, an etching treatment, a plating treatment and the like. The roughening treatment may be carried out by any one method or a combination of two or more. When two or more kinds are combined, the physical method and the chemical method may be combined, the chemical methods may be combined, or the physical methods may be combined.

The circuit sheet of the present disclosure includes an insulating portion provided in at least a part of the space between circuits. Examples of the insulating material used for forming the insulating portion of the circuit sheet include materials containing resins such as epoxy resin, phenol resin, urea resin, melamine resin, urethane resin, silicone resin, unsaturated polyester resin, and acrylic resin. The resin contained in the insulating material may be one kind or two or more kinds. The insulating material may contain components other than the resin, such as an inorganic filler, if necessary.

The width of the insulating portion when observing the element mounting surface of the circuit sheet is not particularly limited, and may be selected according to the application of the circuit sheet and the like. For example, the width of the insulating portion may be 100 μm to 100 mm. When the width of the insulating portion is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.

The thickness of the insulating portion is not particularly limited and can be selected according to the application of the circuit sheet and the like. The thickness of the insulating portion (thickness of the insulating portion / thickness of the circuit) with respect to the thickness of the circuit is preferably 0.5 or more from the viewpoint of ensuring sufficient insulating properties, and the insulating portion positions a plurality of circuits. From the viewpoint of preferably holding, 0.7 or more is more preferable, and from the viewpoint of reducing the pressure difference between the circuit and the insulating portion at the time of crimping in the process of manufacturing the circuit board, 0.9 or more is further preferable. Further, the thickness of the insulating portion / the thickness of the circuit is preferably 1.0 or less, more preferably 0.99 or less, from the viewpoint of workability of element mounting.
When the thickness of the insulating portion is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.

The circuit sheet of the present disclosure preferably has a surface in which a step on the side surface of the circuit is parallel to at least one of the element mounting surface and the surface opposite to the element mounting surface. As a result, it is possible to suppress peeling between the circuit and the insulating portion due to an increase in the area of the portion where the circuit and the insulating portion are in contact with each other, and to suppress peeling on the side surface of the circuit due to a shearing force generated near the step. ..

In the circuit sheet of the present disclosure, when the step on the side surface of the circuit has a surface parallel to at least one of the element mounting surface and the surface opposite to the element mounting surface, the width of the above-mentioned surface suppresses the separation between the circuit and the insulating portion. From the viewpoint of From the viewpoint, it is more preferably more than 500 μm. The width of the above-mentioned surface is 5000 μm or less from the viewpoint of ensuring a balance between element mounting and heat dissipation in the case of a step in which the area of the surface opposite to the element mounting surface is smaller than the area of the element mounting surface. It is preferable, and it is more preferably 3000 μm or less from the viewpoint of widening the bonding area between the insulating layer and the circuit to secure the heat radiation area. In the case of a step in which the area of the element mounting surface is smaller than the area of the surface opposite to the element mounting surface, if the element mounting area can be secured, the heat dissipation area can be secured by increasing the width as described above as much as possible.
When the width of the above-mentioned surface is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above-mentioned value.

In the circuit sheet of the present disclosure, the circuit may have a region in which the cross-sectional shape of the circuit in the thickness direction of the circuit is a substantially convex shape, a substantially cross shape, a substantially T shape, or the like, and the thickness of the circuit. From the viewpoint of suppressing the shearing force generated at both ends in the direction, it is preferable to have a region having a substantially T-shape. When the cross-sectional shape of the circuit in the thickness direction of the circuit has a region having a substantially convex shape, a substantially cross shape, or the like, the cross section of the circuit may be a cross section in a direction parallel to the length direction of the circuit sheet. , The cross section may be parallel to the width direction of the circuit sheet. Further, when the circuit sheet has a region in which the cross-sectional shape of the circuit is substantially T-shaped, the width of the cross section on the element mounting surface side may be larger, and the width of the cross section on the surface side opposite to the element mounting surface may be larger. It may be larger.

When the circuit sheet has a region in which the cross-sectional shape of the circuit is substantially convex or substantially T-shaped, the width of the element mounting surface side and the surface side opposite to the element mounting surface, whichever has the smaller cross-sectional width ( The ratio (width 2 / width 1) of the width (width 2) having a larger cross-sectional width to the width 1) is preferably 0.2 to less than 1, and preferably 0.5 to less than 1. More preferred.

When viewed in the thickness direction of the circuit, the circuit sheet of the present disclosure preferably has a step on the outer circumference of the circuit, and more preferably on the entire outer circumference of the circuit. By providing the step on the entire outer circumference of the circuit, there are no places where peeling is likely to occur, and peeling on the side surface of the circuit can be suitably suppressed. Further, in the circuit sheet of the present disclosure, when viewed in the thickness direction of the circuit, a step may be provided on the inner circumference of the circuit, or may be provided on the entire inner circumference of the circuit. .. By providing the step on the entire inner circumference of the circuit, peeling on the side surface of the circuit can be suitably suppressed.

In the circuit sheet of the present disclosure, when viewed in the thickness direction of the circuit, a step is provided inside the circuit, and the insulating portion provided in the space inside the circuit is the space around the circuit. It is preferable to connect to the insulating portion provided in the above at two or more places. By connecting the insulating portion provided inside the circuit and the insulating portion provided outside the circuit at two or more points, the area of the portion where the circuit and the insulating portion are in contact with each other is preferably increased. Peeling between the circuit and the insulating portion is less likely to occur. In particular, the insulating portion provided inside the circuit is less likely to be separated from the circuit. Further, it is preferable that the portions where the circuit and the insulating portion are in contact with each other are opposed to each other among the two or more portions where the circuit and the insulating portion are in contact with each other. When a shearing force is generated in the circuit due to the above-mentioned portions facing each other, it is possible to preferably prevent the circuit from tilting and peeling from the insulating portion.

The width of the insulating portion in the portion where the insulating portion provided inside the circuit and the insulating portion provided outside the circuit are connected is 500 μm or more from the viewpoint of suppressing separation between the circuit and the insulating portion. It is preferable, and it is more preferably 1000 μm or more from the viewpoint of easily securing the strength of the insulating portion in the above-mentioned connected portion. The width of the insulating portion in the above-mentioned portion is preferably 5000 μm or less from the viewpoint of easily securing the heat dissipation area, the element mounting area, etc., and from the viewpoint of easily forming the insulating portion when the insulating portion is formed by transfer molding. It is more preferably 3000 μm or less.
When the width of the insulating portion in the above-mentioned portion is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above-mentioned value.

The thickness of the insulating portion at the portion where the insulating portion provided inside the circuit and the insulating portion provided outside the circuit are connected is the separation between the circuit and the insulating portion with respect to the thickness of the insulating portion. It is preferably 10% or more from the viewpoint of suppressing the above, and more preferably 40% or more from the viewpoint of ensuring the strength of the insulating portion in the above-mentioned connected portion. The thickness of the insulating portion in the above-mentioned portion is preferably 90% or less with respect to the thickness of the insulating portion from the viewpoint of ensuring the strength of the circuit, and is adhered to the above-mentioned connecting portion in the circuit. From the viewpoint of suppressing deformation of the formed portion (thin-walled portion of the circuit), it is more preferably 60% or less.
If the thickness of the insulating portion in the above-mentioned portion is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected locations may be used as the above-mentioned value.

The portion where the insulating portion provided inside the circuit and the insulating portion provided outside the circuit are connected may be provided on the element mounting surface side, and may be provided on the surface side opposite to the element mounting surface. It may have been.

In the circuit sheet of the present disclosure, the surface roughness of the side surface (hereinafter, also referred to as "surface roughness A") is the surface roughness of the element mounting surface (hereinafter, also referred to as "surface roughness B") and the element mounting surface. It is preferably larger than at least one of the surface roughness of the opposite surface (hereinafter, also referred to as "surface roughness C"), and more preferably larger than the surface roughness of the element mounting surface.

The surface roughness of the element mounting surface and the surface roughness of the surface opposite to the element mounting surface (for example, the surface in contact with the insulating layer) may be the same or different. From the viewpoint of suppressing peeling between the circuit and the insulating layer, the surface roughness of the surface opposite to the element mounting surface is preferably larger than the surface roughness of the element mounting surface of the circuit.

In the present disclosure, the surface roughness of the circuit may be expressed by the arithmetic mean roughness (Ra) defined by JIS B 0601 (2001).
The surface roughness A expressed in Ra is preferably 0.2 μm or more, and more preferably 0.5 μm or more from the viewpoint of stably ensuring the adhesive force between the circuit and the insulating portion. From the viewpoint of obtaining a strong adhesive force between the circuit and the insulating portion, it is more preferably 1.0 μm or more. From the viewpoint of avoiding local electric field concentration when a high voltage is applied, the surface roughness A expressed in Ra may be 10 μm or less.

The surface roughness B represented by Ra is preferably less than 0.4 μm, more preferably 0.3 μm or less, and further preferably 0.2 μm or less.

The surface roughness C when represented by Ra is preferably 0.2 μm or more, more preferably 0.5 μm or more, and further preferably 1.0 μm or more. From the viewpoint of avoiding local electric field concentration when a high voltage is applied, the surface roughness C expressed in Ra may be 10 μm or less.

The relative ratio of the surface roughness A and the surface roughness B when expressed in Ra is not particularly limited. For example, the surface roughness A may be more than 1 time to 100 times the surface roughness B.

Hereinafter, specific examples of the conventional circuit sheet and the circuit sheet of the present disclosure will be described with reference to FIGS. 1A to 1E.

FIG. 1D is a schematic plan view of a specific example of a conventional circuit sheet when viewed from the element mounting surface, and FIG. 1E is a cross-sectional view taken along the line AA of FIG. 1D. The circuit sheet 20 shown in FIGS. 1D and 1E includes a circuit 1 and an insulating portion 2 provided between the circuits 1. As shown in FIGS. 1D and 1E, the side surface of the circuit 1 between the element mounting surface and the surface opposite to the element mounting surface does not have a step. Therefore, heat treatment of the circuit sheet 20, crimping in the process of manufacturing the circuit board, and the like are likely to cause peeling between the side surface of the circuit 1 and the insulating portion 2, and air bubbles are trapped at the peeled portion. In addition, the reliability of the circuit sheet 20 may be impaired due to a decrease in insulation resistance or the like.

1A is a schematic plan view of a specific example of the circuit sheet of the present disclosure, FIG. 1B is a sectional view taken along line AA of FIG. 1A, and FIG. 1C is an enlarged view of FIG. 1B. The circuit sheet 10 shown in FIGS. 1A and 1B includes an insulating portion 2 provided between the circuit 1 and the circuit 1, and is located between the element mounting surface and the surface opposite to the element mounting surface in the circuit 1. The side surface has a step 3. Therefore, the area of the portion where the circuit 1 and the insulating portion 2 are in contact with each other becomes large, and the circuit 1 and the insulating portion 2 are less likely to be separated from each other. Therefore, when the circuit sheet 10 is heat-treated or crimped in the process of manufacturing the circuit board, peeling is unlikely to occur between the side surface of the circuit 1 and the insulating portion 2, and air bubbles are trapped at the peeled portion. The circuit sheet 10 is excellent in reliability because it is suppressed from being damaged or the insulation resistance is lowered.

In the circuit sheet 10, when viewed from the element mounting surface in the thickness direction of the circuit 1, the step 3 is provided on the entire inner circumference of the circuit 1 and the entire outer circumference of the circuit 1. Further, as shown in FIG. 1A, the insulating portion 2 provided in the space inside the circuit 1 in the direction parallel to the element mounting surface and orthogonal to the line AA is an insulating portion provided in the space around the circuit 1. It is connected at 2 and 2 places. Further, as shown in FIGS. 1B and 1C, the step 3 has a surface 3A parallel to the element mounting surface and the surface opposite to the element mounting surface.

The method for manufacturing the circuit sheet of the present disclosure is not particularly limited. The method for manufacturing the circuit sheet of the present disclosure includes, for example, a step of filling a space formed by the circuit, which is arranged on a temporary base material, with an insulating material, and is necessary when the insulating material is a resin or the like. Accordingly, it may have a step of curing the filled insulating material. Examples of the space formed by the circuits include spaces between circuits.

The circuit may be formed on the temporary substrate by arranging the metal on the temporary substrate and then performing etching, and etching from both sides of the metal plate (that is, two facing main surfaces). It is preferable to form a circuit by etching.

In the present disclosure, the temporary base material can temporarily fix the circuit before filling the space formed by the circuit arranged on the temporary base material with the insulating material, and can be removed from the circuit after filling with the insulating material. Say something. Here, the fact that the circuit is temporarily fixed means that the circuit maintains a relative positional relationship due to contact with the temporary base material, and does not necessarily mean that the circuit does not move completely. ..

Examples of the temporary base material include a resin film and the like. Examples of the resin film that can be used as the temporary base material include a resin film having a support film and an adhesive layer formed on the support film.

<Circuit board of the first embodiment>
The circuit board of the first embodiment of the present disclosure includes the circuit sheet of the first embodiment of the present disclosure described above, an insulating layer arranged so as to be in contact with a surface opposite to the element mounting surface of the circuit sheet, and the insulation. A heat radiating member arranged so as to be in contact with the layer is provided in this order. The circuit sheet of the present disclosure can reduce the situation where a uniform pressure is not applied to the insulating layer because the circuit is peeled off from the insulating portion and tilted, or a gap is generated between the circuit and the insulating portion. .. In addition, the thickness of the insulating layer of the manufactured circuit board is excellent in uniformity. As a result, the circuit board of the present disclosure tends to have high adhesive reliability and excellent heat dissipation, insulation and the like.

The types of the insulating layer and the heat radiating member used for the circuit board are not particularly limited, and can be selected from those generally used for the circuit board. The preferred form of the insulating material used for forming the insulating layer may be the same as the preferred form of the insulating material used for forming the insulating portion. The material of the heat radiating member is not particularly limited, and examples thereof include copper, aluminum, tungsten copper, copper alloys such as molybdenum copper, and nickel-plated copper. The type of the heat radiating member is not particularly limited, and may be a member having a heat radiating function such as a heat spreader or a heat sink, a case having an air or water flow path, a metal foil, a filler resin composite, or the like. The surface of the heat radiating member may be smooth, and may be roughened to improve the adhesiveness with the insulating layer.

The thickness of the insulating layer is not particularly limited and can be selected according to the application of the circuit board. From the viewpoint of ensuring sufficient insulating properties, the thickness of the insulating layer is preferably 50 μm or more, and more preferably 100 μm or more from the viewpoint of unevenness followability when the circuit sheet has irregularities. From the viewpoint of absorbing the shearing force due to pressure, it is more preferably 150 μm or more.

From the viewpoint of ensuring sufficient heat dissipation, the thickness of the insulating layer is preferably 400 μm or less, and from the viewpoint of less likely to generate shearing force due to pressure, it is more preferably 300 μm or less, and more preferably 250 μm or less. Is even more preferable.

<Manufacturing method of circuit board of the first embodiment>
The method for manufacturing the circuit board of the first embodiment of the present disclosure includes the circuit sheet of the first embodiment of the present disclosure described above, an insulating layer arranged on a surface opposite to the element mounting surface of the circuit sheet, and a heat radiating member. And, there is a step of pressurizing the laminated body in the state which arranged in this order in the thickness direction.

The method of pressurizing the laminate in the above method is not particularly limited, and can be selected from the methods generally performed in the circuit board manufacturing process.

<Circuit board of the second embodiment>
The circuit board of the second embodiment of the present disclosure comprises a circuit composed of a conductor and having a first surface and a second surface located on a side opposite to the first surface, and the second surface of the circuit. An insulating layer arranged so as to be in contact with a surface and a heat radiating member arranged so as to be in contact with the insulating layer are provided in this order in the thickness direction, and the first surface is viewed from the circuit side in a plan view. There is a region where the outer peripheral edge portion of the second surface and the outer peripheral edge portion of the second surface do not overlap.

The circuit board of the present disclosure has a region in which the outer peripheral edge portion of the first surface and the outer peripheral edge portion of the second surface do not overlap in a plan view from the circuit side. As a result, when the first surface of the circuit is pressurized, the pressure on the second surface at the outer peripheral edge of the first surface of the circuit is distributed. Therefore, by releasing the pressurization of the circuit board after the process of manufacturing the circuit board, the phenomenon (springback) of trying to return from the compression due to the pressurization at the outer peripheral edge of the circuit is suppressed, and the outer peripheral edge of the circuit is suppressed. Peeling is less likely to occur between the and the insulating layer. Since peeling is less likely to occur between the outer peripheral edge of the circuit and the insulating layer, it is possible to prevent the reliability from being impaired due to trapping air bubbles at the peeling point or deterioration of insulation resistance. Therefore, the circuit board of the present disclosure is excellent in reliability.

In particular, when there are a plurality of circuits and a potential difference occurs between adjacent circuits, the insulation resistance of the circuit board deteriorates if air bubbles, voids, etc. are generated in the outer peripheral edge of the circuit. It is important to suppress the peeling between the and the insulating layer. Even in such a case, the circuit board of the present disclosure can suitably suppress a decrease in insulation resistance and is excellent in reliability.

When the first surface of the circuit is pressurized and the pressure on the second surface at the outer edge of the first surface of the circuit is distributed, it goes to the outer edge of the first surface of the circuit. Since the concentration of pressure is suppressed, the deformation of the circuit is suppressed in the vicinity of the outer peripheral edge portion of the first surface, and the damage of the insulating layer is also suppressed.

In particular, when the circuit board includes a circuit having a large thickness, for example, a thick copper circuit, the springback force at the outer peripheral edge of the circuit when the pressurization of the circuit board is released is large, and the springback causes the outer peripheral edge of the circuit. Peeling is likely to occur between the portion and the insulating layer. On the other hand, in the circuit board of the present disclosure, even when the thickness of the circuit is large, the springback force is suppressed, so that the circuit and the insulating layer are less likely to be separated, and the circuit board is excellent in reliability. ..

The circuit board of the present disclosure may be a circuit board in which a circuit, an insulating layer, and a heat radiating member are crimped in the thickness direction.

The circuit board of the present disclosure comprises a circuit composed of a conductor and having a first surface and a second surface located on the opposite side of the first surface. The material of the circuit is not particularly limited as long as it is a conductor, and examples thereof include metal. Examples of the metal include copper, silver, chromium copper, tungsten copper, nickel, nickel-plated copper, aluminum, and aluminum whose surface is modified to alumite. From the viewpoint of conductivity, the metal preferably contains copper. The circuit board may include a plurality of circuits.

The thickness of the circuit is not particularly limited and can be selected according to the application of the circuit board and the like. From the viewpoint of increasing the current of the circuit, the thickness of the circuit is preferably more than 120 μm, more preferably more than 450 μm, further preferably 700 μm or more, and particularly preferably 1000 μm or more. From the viewpoint of weight reduction and height reduction, the thickness of the circuit may be 5000 μm or less, or 3000 μm or less. When the thickness of the circuit is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.
When a part of the circuit is embedded in the insulating layer or the like, the thickness of the embedded part is also included in the thickness of the circuit.

The width of the circuit when observing the first surface of the circuit is not particularly limited, and may be selected according to the application of the circuit board and the like. For example, the width of the circuit may be 100 μm to 100 mm. When the width of the circuit is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value. Further, the first surface of the circuit may be an element mounting surface on which the element is mounted.

The circuit can be obtained, for example, by processing a metal plate into a circuit state having a desired shape. The processing method is not particularly limited, and can be performed by a known method such as punching, cutting, etching, and processing in which they are combined. When the circuit is manufactured by etching, the circuit may be formed by etching from both sides (that is, two main surfaces facing each other) of the metal plate. When etching from both sides of the metal plate, both sides may be etched at the same time, or both sides may be etched alternately.

The circuit may be roughened. When a circuit comes into contact with an insulating layer, which will be described later, during the manufacturing process of a circuit board, if the surface in contact with the insulating layer is at least roughened, it is in a state where it can be sufficiently adhered to the insulating layer while suppressing the generation of voids. be able to. Specifically, it is considered that the adhesion due to the Van der Waals force can be improved by roughening the surface in contact with the insulating layer of the circuit to improve the pull-out force due to the anchor effect or increase the adhesion area.

The circuit board of the present disclosure may be provided with an insulating portion in at least one of the space between the circuits and the periphery of the circuit, and when a plurality of circuits are present, the insulating portion may be provided between the plurality of circuits. good. Examples of the insulating material used for forming the insulating portion include materials containing resins such as epoxy resin, phenol resin, urea resin, melamine resin, urethane resin, silicone resin, unsaturated polyester resin, and acrylic resin. The resin contained in the insulating material may be one kind or two or more kinds. The insulating material may contain components other than the resin, such as an inorganic filler, if necessary.

The width of the insulating portion when observing the first surface of the circuit is not particularly limited, and may be selected according to the application of the circuit board and the like. For example, the width of the insulating portion may be 100 μm to 100 mm. When the width of the insulating portion is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.

The thickness of the insulating portion is not particularly limited and can be selected according to the application of the circuit board and the like. The thickness of the insulating portion (thickness of the insulating portion / thickness of the circuit) with respect to the thickness of the circuit is preferably 0.5 or more from the viewpoint of ensuring sufficient insulating properties, and the insulating portion positions a plurality of circuits. From the viewpoint of preferably holding, 0.7 or more is more preferable, and from the viewpoint of reducing the pressure difference between the circuit and the insulating portion at the time of crimping in the process of manufacturing the circuit board, 0.9 or more is further preferable. Further, the thickness of the insulating portion / the thickness of the circuit is preferably 1.0 or less, more preferably 0.99 or less, from the viewpoint of workability of element mounting.
When the thickness of the insulating portion is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.

Further, when the thickness of the circuit is larger than the thickness of the insulating portion, that is, when the thickness of the insulating portion / the thickness of the circuit is less than 1, the thickness of the circuit is equal to the thickness of the insulating portion. When the first surface of the circuit is pressurized, the pressure on the second surface at the outer peripheral edge of the first surface tends to be concentrated. Therefore, when pressurization is performed in the process of manufacturing the circuit board, when springback occurs, peeling is likely to occur between the side surface of the circuit and the insulating portion, and as a result, the insulation resistance of the circuit board is lowered. There is a risk that the circuit and the insulating part may be misaligned in the thickness direction of the circuit board.
In the present disclosure, the side surface of the circuit refers to a surface other than the first surface and the second surface of the circuit.

On the other hand, in the circuit board of the present disclosure, when the first surface of the circuit is pressurized, the pressure on the second surface at the outer peripheral edge of the first surface is dispersed, so that the circuit board is manufactured. Peeling is unlikely to occur between the side surface of the circuit and the insulating portion when pressurization is performed in the process or when springback occurs. Therefore, it is possible to suppress a decrease in insulation resistance due to peeling between the side surface of the circuit and the insulating portion, and a positional deviation between the circuit and the insulating portion in the thickness direction of the circuit board.

The connection point between the side surface of the circuit and the first surface or the second surface may be angular or rounded.

Further, the side surface of the circuit may be parallel to the thickness direction of the circuit board, or may be inclined so as to intersect the thickness direction of the circuit board.

In the circuit board of the present disclosure, it is sufficient that there is a region in which the outer peripheral edge portion of the first surface and the outer peripheral edge portion of the second surface do not overlap in a plan view from the circuit side. The ratio of the region where the outer peripheral edge portion of the second surface overlaps with respect to the entire outer peripheral edge portion of the first surface is preferably 0% to 50%, that is, 0%, that is, the circuit side. It is more preferable that the entire outer peripheral edge portion of the first surface does not overlap with the outer peripheral edge portion of the second surface in a plan view from the above.

In the circuit board of the present disclosure, the shortest distance between the outer peripheral edge of the first surface and the outer peripheral edge of the second surface is
It is preferably 0.01 mm or more and less than 1.0 mm, more preferably 0.02 mm to 0.5 mm, effectively suppresses springback, and reduces the amount of change even when springback occurs. From the viewpoint, it is more preferably 0.03 mm or more and less than 0.5 mm.

In the circuit board of the present disclosure, when an insulating portion is provided in at least one of the space between the circuits and the periphery of the circuit, the surface roughness of the side surface (hereinafter, also referred to as “surface roughness A”) becomes the element mounting surface. It may be larger than at least one of the surface roughness of the first surface (hereinafter, also referred to as "surface roughness B") and the surface roughness of the second surface (hereinafter, also referred to as "surface roughness C"). It is preferably larger than the surface roughness of the first surface.

The surface roughness of the first surface and the surface roughness of the second surface may be the same or different. From the viewpoint of suppressing peeling between the circuit and the insulating layer, the surface roughness of the second surface is preferably larger than the surface roughness of the first surface.

In the present disclosure, the surface roughness of the circuit may be expressed by the arithmetic mean roughness (Ra) defined by JIS B 0601 (2001).
The surface roughness A when expressed in Ra is preferably 0.2 μm or more, and is 0 from the viewpoint of stably ensuring the adhesive force between the side surface of the circuit and the insulating portion when the insulating portion is present. It is more preferably 0.4 μm or more, and further preferably 0.6 μm or more from the viewpoint of obtaining a strong adhesive force between the side surface of the circuit and the insulating portion when the insulating portion is present. From the viewpoint of avoiding local electric field concentration when a high voltage is applied, the surface roughness A expressed in Ra may be 10 μm or less.

The surface roughness C when represented by Ra is preferably 0.2 μm or more, more preferably 0.4 μm or more, and further preferably 0.6 μm or more. From the viewpoint of avoiding local electric field concentration when a high voltage is applied, the surface roughness C expressed in Ra may be 10 μm or less.

The circuit board of the present disclosure is insulated from a circuit, a circuit sheet having an insulating portion in a space between the circuits and at least one of the periphery of the circuit, and an insulating layer arranged so as to be in contact with a second surface of the circuit. A heat radiating member arranged so as to be in contact with the layer may be provided in this order in the thickness direction.

The method of manufacturing the circuit sheet is not particularly limited. The method for manufacturing a circuit sheet includes, for example, a step of filling a space formed by the circuit, which is arranged on a temporary base material, with an insulating material, and when the insulating material is a resin or the like, if necessary, It may have a step of curing the filled insulating material. Examples of the space formed by the circuits include spaces between circuits.

The circuit board of the present disclosure includes an insulating layer arranged so as to be in contact with the second surface of the circuit. The type of the insulating layer used for the circuit board is not particularly limited, and can be selected from those generally used for the circuit board. The preferred form of the insulating material used for forming the insulating layer may be the same as the preferred form of the insulating material used for forming the insulating portion.

The thickness of the insulating layer is not particularly limited and can be selected according to the application of the circuit board. From the viewpoint of ensuring sufficient insulation, the thickness of the insulating layer is preferably 50 μm or more, and when there are irregularities in the circuit, insulating portion, etc., it is 100 μm or more from the viewpoint of unevenness followability. More preferably, it is 150 μm or more from the viewpoint of absorbing the shearing force due to pressure.

The circuit board of the present disclosure includes a heat radiating member arranged so as to be in contact with the insulating layer. The type of heat radiating member used for the circuit board is not particularly limited, and can be selected from those generally used for the circuit board. The material of the heat radiating member is not particularly limited, and examples thereof include copper, aluminum, tungsten copper, copper alloys such as molybdenum copper, and nickel-plated copper. The type of the heat radiating member is not particularly limited, and may be a member having a heat radiating function such as a heat spreader or a heat sink, a case having an air or water flow path, a metal foil, a filler resin composite, or the like. The surface of the heat radiating member may be smooth, and may be roughened to improve the adhesiveness with the insulating layer.

The thickness of the heat radiating member is not particularly limited and can be selected according to the application of the circuit board and the like. From the viewpoint of heat dissipation, the thickness of the heat dissipation member is preferably more than 120 μm, more preferably 1000 μm, and 1500 μm or more from the viewpoint of securing a volume for heat diffusion and further improving heat dissipation. Is more preferable. From the viewpoint of miniaturization and low profile of the circuit board, the thickness of the heat radiating member is preferably 10,000 μm or less, and more preferably 3000 μm or less.
When the thickness of the heat radiating member is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.

The ratio of the thickness of the circuit to the thickness of the heat radiating member (circuit thickness / average thickness of the heat radiating member) is preferably 0.2 to 25, and more preferably 1 to 25.

In the circuit board of the present disclosure, from the viewpoint of heat dissipation of the circuit board, it is preferable that the area (area B) of the surface of the heat radiating member on the insulating layer side is larger than the area (area A) of the second surface of the circuit. For example, the ratio of the area B of the heat radiating member to the area A of the circuit may be more than 1 and 30 or less, and is preferably 2 to 10.

In the circuit board of the present disclosure, the partial discharge start voltage of the insulating layer is preferably 1.0 kV or more, and more preferably 2.5 kV or more, from the viewpoint of insulation resistance.
The measurement of the partial discharge start voltage may be performed in accordance with the measurement standard IEC60664-1.
Specifically, after connecting the circuit and the heat radiating member to the power supply, the entire circuit board is put into Fluorinert to measure the partial discharge start voltage. The measurement conditions are that the measurement start voltage is set to 0 (V), the voltage is gradually increased by 100 (V) and held for 1 second repeatedly, and the voltage when the amount of charge exceeds 10 (pC) is partially discharged. Let it be the starting voltage (kV).

In the circuit board of the present disclosure, the dielectric breakdown voltage between the heat radiating member and the circuit is preferably 1.5 kV or more, more preferably 2.5 kV or more, and further preferably 4 kV or more.
The dielectric breakdown voltage between the heat radiating member and the circuit may be measured as follows, for example. After connecting the circuit and the heat dissipation member to the power supply, the entire circuit board is placed in Fluorinert to measure the breakdown voltage. The measurement conditions are that the measurement start voltage is set to 0 (V), the voltage is gradually increased by 100 (V) and held for 1 second repeatedly, and the voltage when the current value exceeds 0.2 (mA) is set. It is assumed to be a breakdown voltage (kV).

<Circuit sheet of the second embodiment>
The circuit sheet of the second embodiment of the present disclosure comprises a conductor, a first surface, and a space between the circuit and a circuit having a second surface located on the opposite side of the first surface. An insulating portion provided on at least one of the periphery of the circuit is provided, and there is a region in which the outer peripheral edge portion of the first surface and the outer peripheral edge portion of the second surface do not overlap in a plan view. do. By using the circuit sheet of the present disclosure, the circuit board of the present disclosure described above can be manufactured. The preferred form of each configuration in the circuit sheet of the present disclosure is the same as the preferred form of each configuration in the circuit board of the second embodiment of the present disclosure described above.

<Manufacturing method 1 of the circuit board of the second embodiment>
The method 1 for manufacturing a circuit board of the second embodiment of the present disclosure includes the circuit sheet of the second embodiment of the present disclosure described above, an insulating layer arranged so as to be in contact with the second surface, a heat radiating member, and the like. It has a step of pressurizing the laminated body in the state which arranged in this order in the thickness direction in the thickness direction.

The method of pressurizing the laminate in the above manufacturing method 1 is not particularly limited, and can be selected from the methods generally performed in the circuit board manufacturing process.

The pressurizing step is preferably performed with a cushioning material that can be deformed by pressurization arranged on the first surface of the circuit. By arranging the cushion material on the first surface of the circuit, the pressure applied to the first surface is dispersed, and the circuit, the insulating layer, and the heat radiating member tend to be sufficiently brought into close contact with each other. The step of pressurizing may be performed in a state where the cushion material is also arranged on the heat radiating member side of the laminated body.

Examples of the cushioning material used include fluororubber, Teflon (registered trademark), polyethylene terephthalate (PET), polyimide, polyamide, polyamideimide, polyethylene, non-woven fabric, non-woven paper, and their composite layers and laminated materials. ..

<Manufacturing method 2 of the circuit board of the second embodiment>
The method 2 for manufacturing a circuit board according to the second embodiment of the present disclosure is the method for manufacturing a circuit board for manufacturing the circuit board according to the second embodiment of the present disclosure described above, wherein the circuit and the second of the circuits are used. A step of pressurizing a laminated body in a state where the insulating layer arranged so as to be in contact with a surface and the heat radiating member arranged so as to be in contact with the insulating layer are arranged in this order in the thickness direction. Have. The circuit board manufacturing method 1 of the present disclosure differs from the circuit board manufacturing method 1 described above in that a circuit is used instead of the circuit sheet.

Hereinafter, the conventional circuit board and specific examples 1 and 2 of the circuit board of the present disclosure will be described with reference to FIGS. 2A to 2D.

(Specific example of conventional circuit board)
FIG. 2D is a cross-sectional view showing a schematic configuration of a specific example of a conventional circuit board. As shown in FIG. 2D, the circuit board 130 includes a circuit sheet 26 including a circuit 21 and an insulating portion 24, an insulating layer 12, and a heat radiating member 13 in this order in the thickness direction. The insulating portion 24 is provided in the space between the circuits 21 and around the circuits 21. In the circuit board 130, there is no region in which the outer peripheral edge portion A of the first surface and the outer peripheral edge portion B of the second surface do not overlap in a plan view from the circuit 21 side.

In the circuit board 130, when the first surface of the circuit 21 is pressurized, the pressure from the outer peripheral edge portion A of the first surface of the circuit 21 to the outer peripheral edge portion B of the second surface is not dispersed. When the pressurization of the circuit board 130 is released, the springback at the outer peripheral edge portion B of the second surface tends to cause peeling between the outer peripheral edge portion B of the circuit 21 and the insulating layer 12, and at the peeled portion, peeling occurs. The reliability of the circuit board 130 may be impaired by trapping air bubbles or lowering the insulation resistance.

(Specific Example 1 of Circuit Board)
FIG. 2A is a cross-sectional view showing a schematic configuration of a specific example 1 of the circuit board of the present disclosure, and FIG. 2B is a plan view from the circuit side showing the schematic configuration of the specific example 1 of the circuit board of the present disclosure. .. FIG. 2A shows that the circuit board 110 including the circuit 11, the insulating layer 12, and the heat radiating member 13 is manufactured by pressurizing the laminated body including the circuit 11 and the heat radiating member 13 from the direction of the arrow Y using the cushion material 15. ing. In FIG. 2B, the heat radiating member 13 is omitted.

The circuit board 110 includes the circuit 11, the insulating layer 12, and the heat radiating member 13 in this order in the thickness direction (that is, the arrow X direction). In the circuit board 110, the entire outer peripheral edge portion A of the first surface does not overlap with the outer peripheral edge portion B of the second surface in a plan view from the circuit 11 side.

In the circuit board 110, when the first surface of the circuit 11 is pressurized, the pressure from the outer peripheral edge portion A of the first surface of the circuit 11 to the second surface is dispersed. Therefore, when the pressurization of the circuit board 110 is released, springback at the outer peripheral edge portion B of the second surface is suppressed, and peeling between the outer peripheral edge portion B and the insulating layer 12 is unlikely to occur, and as a result, the result is The circuit board 110 is excellent in reliability because it is possible to prevent the reliability from being impaired due to trapping air bubbles at the peeled portion or deterioration of the insulation resistance.

In FIG. 2A, the connection point between the side surface of the circuit 11 and the first surface is rounded, but may be angular. Further, the circuit board 110 may be provided with an insulating portion around the circuit 11 as in the specific example 2 of the circuit board described later.

(Specific example 2 of circuit board)
FIG. 2C is a cross-sectional view showing a schematic configuration of a specific example 2 of the circuit board of the present disclosure. As shown in FIG. 2C, the circuit board 120 includes a circuit sheet 16 including a circuit 11'and an insulating portion 14, an insulating layer 12, and a heat radiating member 13 in this order in the thickness direction. Specific Example 2 of the circuit board is different from Specific Example 1 of the circuit board in that the cross-sectional shape of the circuit is convex downward and an insulating portion is provided around the circuit.

In the circuit board 120, the entire outer peripheral edge portion A of the first surface does not overlap with the outer peripheral edge portion B of the second surface in a plan view from the circuit 11'side. As a result, as with the circuit board 110, peeling is unlikely to occur between the outer peripheral edge of the circuit 11'and the insulating layer 12, and as a result, air bubbles are trapped at the peeled portion and the insulation resistance is lowered. The circuit board 120 is excellent in reliability because it is suppressed that the reliability is impaired by the above.

<Circuit sheet of the third embodiment>
The circuit sheet of the third embodiment of the present disclosure includes two or more circuits composed of conductors, and in all combinations of two circuits that are independent of each other and are adjacent to each other, the element mounting surface of the circuit. The highly elastic member is located on a straight line in an arbitrary direction that is independent of each other, passes between two adjacent circuits, and is parallel to the element mounting surface.

In the circuit sheet of the present embodiment, when viewed from the element mounting surface of the circuit, they are independent of each other, pass between two adjacent circuits, and are on a straight line in an arbitrary direction parallel to the element mounting surface. Highly elastic member is located. As a result, the circuit and the highly elastic member are arranged as compared with the circuit sheet in which the highly elastic member does not exist on at least one straight line passing between two adjacent circuits and parallel to the element mounting surface. Deformation of the circuit sheet in the non-linear region is suppressed, and the occurrence of warpage is also suppressed.

The highly elastic member may be a circuit or may be the highly elastic member described in the fourth embodiment described later.

The circuit sheet of this embodiment includes two or more circuits made of conductors. The material of the circuit is not particularly limited as long as it is a conductor, and examples thereof include metal. Examples of the metal include copper, silver, chromium copper, tungsten copper, nickel, nickel-plated copper, aluminum, and aluminum whose surface is modified to alumite. From the viewpoint of conductivity, the metal preferably contains copper.

The thickness of the circuit is not particularly limited and can be selected according to the application of the circuit sheet and the like. From the viewpoint of increasing the current of the circuit, the thickness of the circuit is preferably 350 μm or more, and from the viewpoint of heat dissipation using the circuit itself, it is more preferably 500 μm or more, and the circuit is particularly used as a highly elastic member. In some cases, it is more preferably 1000 μm or more from the viewpoint of effectively suppressing the warp of the circuit sheet, the circuit board, and the like. From the viewpoint of weight reduction, height reduction, etc., the thickness of the circuit may be 5000 μm or less. From the viewpoint of circuit workability, it is preferably 3000 μm or less. When the thickness of the circuit is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.
When a part of the circuit is embedded in an adjacent member such as an insulating layer, the thickness of the embedded part is also included in the thickness of the circuit.

The circuit can be obtained, for example, by processing a metal plate into a circuit state having a desired shape. The processing method is not particularly limited, and can be performed by a known method such as punching, cutting, etching, or a combination thereof. From the viewpoint of improving the accuracy in circuit fabrication, it is preferable to form the circuit by etching.

When the circuit is manufactured by etching, the etching method of the metal plate is not particularly limited. From the viewpoint of suppressing the occurrence of the tapered portion of the circuit, it is preferable to form the circuit by etching from both sides (that is, two main surfaces facing each other) of the metal plate.

The circuit sheet of the present embodiment may include an insulating portion provided at least a part between two or more circuits. When the circuit sheet is provided with an insulating portion, it passes through the insulating portion provided between two or more circuits and is on a straight line in an arbitrary direction parallel to the element mounting surface when viewed from the element mounting surface of the circuit. A highly elastic member may be located in.

Examples of the insulating material used for forming the insulating portion include materials containing resins such as epoxy resin, phenol resin, urea resin, melamine resin, urethane resin, silicone resin, unsaturated polyester resin, and acrylic resin. The resin contained in the insulating material may be one kind or two or more kinds. The insulating material may contain components other than the resin, such as an inorganic filler, if necessary.

The thickness of the insulating portion is not particularly limited and can be selected according to the application of the circuit sheet and the like. The thickness of the insulating portion (thickness of the insulating portion / thickness of the circuit) with respect to the thickness of the circuit is preferably 0.05 or more from the viewpoint of maintaining the positional relationship of a plurality of circuits, and secures the strength of the circuit sheet. From the viewpoint of ease, 0.7 or more is more preferable, and from the viewpoint of ensuring symmetry in the thickness direction of the circuit sheet and easily reducing warpage, 0.9 or more is further preferable. Further, the thickness of the insulating portion / the thickness of the circuit is preferably 1.0 or less, more preferably 0.99 or less, from the viewpoint of workability of element mounting.
When the thickness of the insulating portion is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.

When the circuit sheet includes an insulating portion, it is preferable that the insulating portion is provided so that the element mounting surface of the circuit and the surface opposite to the element mounting surface are exposed. In particular, when the front and back surfaces of the circuit have an exposed vertically symmetrical structure, the warp of the circuit sheet can be suitably suppressed.

In the circuit sheet of the present embodiment, the shortest distance between the side surface of a specific circuit and another circuit other than the specific circuit or a highly elastic member other than the circuit from the viewpoint of suitably suppressing the warp of the circuit sheet, the circuit board, or the like. The distance is preferably 10 mm or less, and more preferably 5 mm or less from the viewpoint of miniaturization of the circuit sheet.

In the circuit sheet of the present embodiment, from the viewpoint of insulation between circuits, the shortest distance between a specific circuit and a side surface of another circuit other than the specific circuit or a highly elastic member other than the circuit is 500 μm or more. It is preferable, and it is more preferable that it is 1000 μm or more from the viewpoint of corresponding to a high voltage.

<Circuit sheet of the fourth embodiment>
The circuit sheet of the fourth embodiment of the present disclosure includes at least one circuit made of a conductor, an insulating portion, and a member having a higher Young ratio than the insulating portion, and the circuit and the member having a higher Young ratio are included. The insulating portion is provided in at least a part of the space formed by the arrangement, passes through the insulating portion provided in at least a part of the space when viewed from the element mounting surface of the circuit, and said. At least one of the circuit and the member having a high young ratio (hereinafter, also referred to as “highly elastic member”) is located on a straight line in an arbitrary direction parallel to the element mounting surface.

In the circuit sheet of the present embodiment, the circuit and the height are on a straight line in an arbitrary direction that passes through an insulating portion provided in at least a part of the space and is parallel to the element mounting surface when viewed from the element mounting surface of the circuit. At least one of the elastic members is located. As a result, in the insulating portion, as compared with a circuit sheet in which the circuit and the highly elastic member do not exist on at least one straight line that passes through the insulating portion provided in at least a part of the space and is parallel to the element mounting surface. Deformation of the circuit sheet in the linear region is suppressed, and the occurrence of warpage is also suppressed.

The circuit sheet of this embodiment includes a highly elastic member rather than an insulating portion. The circuit sheet may include only one highly elastic member, or may include two or more highly elastic members.

The material of the highly elastic member is not particularly limited as long as it has a higher Young's modulus than the insulating material, and examples thereof include metal. Examples of the metal include copper, silver, chromium copper, tungsten copper, nickel, nickel-plated copper, aluminum, and aluminum whose surface is modified to alumite.

The material of the highly elastic member may be the same as the material of the circuit. Further, the highly elastic member may be another circuit arranged between the circuits. There may be one or more different circuits.

The shape of the highly elastic member is not particularly limited, and examples thereof include a rectangular shape, a polygonal shape, an irregular shape, a circular shape, a cross shape, and an X shape.

The highly elastic member may have a structure in which two or more linear portions are provided and two or more linear portions intersect, specifically, a cross-shaped structure, an X-shaped structure, or the like. May have. Since the highly elastic member has this structure, the warp of the circuit sheet can be suitably suppressed even when the volume occupied by the insulating portion in the circuit sheet is relatively large.

When the circuit sheet of the present embodiment includes a plurality of circuits, between the side surface of the specific circuit and another circuit other than the specific circuit or a highly elastic member from the viewpoint of suitably suppressing the warp of the circuit sheet or the circuit board. The shortest distance is preferably 10 mm or less, and more preferably 5 mm or less from the viewpoint of miniaturization of the circuit sheet.

In the circuit sheet of the present embodiment, from the viewpoint of insulation between circuits, the shortest distance between a specific circuit and a side surface of another circuit other than the specific circuit or a highly elastic member is preferably 500 μm or more. From the viewpoint of supporting high voltage, it is more preferably 1000 μm or more.

The circuit sheet of the present embodiment may be further provided with an insulating layer which is arranged on the surface side opposite to the element mounting surface of the circuit and holds the relative arrangement of two or more circuits. The preferable configuration of the insulating layer is the same as that described in the section of the circuit board described later. The insulating layer may be provided with an adhesive layer on the surface on the circuit side from the viewpoint of ensuring adhesion to the circuit and preferably maintaining the relative arrangement of two or more circuits.
When the circuit sheet of the present embodiment includes an insulating layer, the circuit sheet may or may not further include an insulating portion provided between two or more circuits.

When the circuit sheet of the present embodiment includes an insulating layer, a circuit board described later may be formed by providing a heat radiating member in contact with the insulating layer.

Hereinafter, specific examples of the conventional circuit sheet, the circuit sheet of the third embodiment, and the circuit sheet of the fourth embodiment will be described with reference to FIGS. 3A to 3C.

FIG. 3A is a schematic configuration diagram of a conventional circuit sheet. The circuit sheet 140 shown in FIG. 3A includes a circuit 31 and an insulating portion 32 provided between the circuits 31. As shown in FIG. 3A, the circuit sheet 140 has a portion where many insulating members are present and no circuit is present in the central portion, and also passes through the insulating portion 32 provided between the circuits 31 with respect to the element mounting surface. It has a configuration in which the circuit 31 does not exist on at least one straight line (for example, the dotted line shown in FIG. 3A) which is parallel to each other. Therefore, there is a problem that deformation is likely to occur in a region of the insulating portion 32 where many insulating members are present, a region including a dotted line shown in FIG. 3A, and the circuit sheet 140 is likely to be warped starting from that portion. ..

FIG. 3B is a schematic configuration diagram of a circuit sheet according to a third embodiment of the present disclosure. The circuit sheet 150 shown in FIG. 3B includes a circuit 31 and an insulating portion 32 provided between the circuits 31, and further includes another circuit 33 between the two circuits 31. In the circuit sheet 150, a circuit (for example, the circuit 31 and another circuit 31) passes through an insulating portion 32 provided between an adjacent circuit 31 and another circuit 33 and is on a straight line in an arbitrary direction parallel to the element mounting surface. Circuit 33) is located.

FIG. 3C is a schematic configuration diagram of a circuit sheet according to a fourth embodiment of the present disclosure. The circuit sheet 160 shown in FIG. 3C includes a circuit 31 and an insulating portion 32 provided between the circuits 31, and is a highly elastic member having a higher Young's modulus than the insulating portion 32 between the two circuits 31. 4 is further provided. In the circuit sheet 160, at least one of the circuit 31 and the highly elastic member 4 is located on a straight line in an arbitrary direction that passes through the insulating portion 32 provided between the two circuits 31 and is parallel to the element mounting surface. ing.

In the circuit sheet 150 of the third embodiment and the circuit sheet 160 of the fourth embodiment, the circuit sheet 150 passes through the insulating portion 32 provided between the two circuits 31 and is on a straight line in an arbitrary direction parallel to the element mounting surface. At least one of a circuit 31, another circuit 33, and a highly elastic member 4 is located in. Therefore, the deformation of the circuit sheet 150 and the circuit sheet 160 in the linear region of the insulating portion 32 is suppressed, and the occurrence of warpage is also suppressed.

The method for manufacturing the circuit sheet of the present disclosure is not particularly limited. The method of manufacturing the circuit sheet of the present disclosure includes, for example, a step of filling a circuit or a space formed by the circuit and a highly elastic member arranged on a temporary base material with an insulating material, and the insulating material is a resin. If necessary, it may have a step of curing the filled insulating material. Examples of the space formed by the circuit include a space between circuits, and examples of the space formed by the circuit and the highly elastic member include, for example, the space between the highly elastic members and the space between the circuit and the highly elastic member. Space can be mentioned.

The circuit and the highly elastic member may be formed on the temporary base material by arranging the metal on the temporary base material and then performing etching.

In the present disclosure, the temporary base material means that a circuit or the like can be temporarily fixed before the space formed by the circuit or the like arranged on the temporary base material is filled with the insulating material, and the circuit or the like can be temporarily fixed after the insulating material is filled. It means something that can be removed from. Here, the fact that the circuit or the like is temporarily fixed means that the circuit or the like maintains a relative positional relationship by contact with the temporary base material, and does not necessarily mean that the circuit or the like does not move completely. It's not a thing.

<Circuit board of the third embodiment>
The circuit board of the third embodiment of the present disclosure is insulated so as to be in contact with the circuit sheet of the third embodiment or the fourth embodiment of the present disclosure described above and the surface opposite to the element mounting surface of the circuit sheet. A layer and a heat radiating member arranged so as to be in contact with the insulating layer are provided in this order. Since the circuit sheet of the present disclosure suppresses the occurrence of warpage, the circuit sheet, the insulating layer, and the heat radiating member can be pressure-bonded with high uniformity, and the thickness of the insulating layer of the manufactured circuit board can be increased. Excellent uniformity. As a result, the circuit board of the present disclosure tends to have high adhesive reliability and excellent heat dissipation, insulation and the like.

The types of the insulating layer and the heat radiating member used for the circuit board are not particularly limited, and can be selected from those generally used for the circuit board. The preferred form of the insulating material used for forming the insulating layer may be the same as the preferred form of the insulating material used for forming the insulating portion. The insulating layer may be provided with an adhesive layer on the surface on the circuit sheet side from the viewpoint of adhesion to the circuit sheet. The material of the heat radiating member is not particularly limited, and examples thereof include copper, aluminum, tungsten copper, copper alloys such as molybdenum copper, and nickel-plated copper. The type of the heat radiating member is not particularly limited, and may be a member having a heat radiating function such as a heat spreader or a heat sink, a case having an air or water flow path, a metal foil, a filler resin composite, or the like. The surface of the heat radiating member may be smooth, and may be roughened to improve the adhesiveness with the insulating layer.

The thickness of the insulating layer is not particularly limited and can be selected according to the application of the circuit board. From the viewpoint of ensuring sufficient insulating properties, the thickness of the insulating layer is preferably 50 μm or more, and from the viewpoint of ensuring sufficient adhesiveness, it is more preferably 80 μm or more, and when adhering the insulating layer. It is more preferably 120 μm or more from the viewpoint of facilitating the handleability of the above, and from the viewpoint of imparting thermal shock resistance.

From the viewpoint of ensuring sufficient heat dissipation, the thickness of the insulating layer is preferably 500 μm or less, and more preferably 400 μm or less from the viewpoint of easily reducing the warp of the circuit board due to the shrinkage of the insulating layer. , 300 μm or less is more preferable.

<Manufacturing method of circuit board of the third embodiment>
The method for manufacturing the circuit board of the third embodiment of the present disclosure is the insulation arranged on the surface opposite to the element mounting surface of the circuit sheet of the third embodiment or the fourth embodiment of the present disclosure described above. The laminated body in which the layers and the heat radiating member are arranged in this order, or the circuit sheet of the present disclosure provided with the above-mentioned insulating layer and the heat radiating member are provided on the insulating layer side of the circuit sheet. It has a step of pressurizing in the thickness direction of the laminated body, which is arranged so as to be located.

<Circuit sheet of the fifth embodiment>
The circuit sheet of the fifth embodiment of the present disclosure includes a circuit and an insulating portion provided between the circuits, and the insulating portion is recessed on the element mounting surface (the surface on which the element is mounted). , Circuit sheet.
Since the insulating portion is recessed on the element mounting surface of the circuit sheet, the circuit is in a relatively protruding state, and the workability of element mounting is improved.

The shape of the recessed part of the insulating part is not particularly limited. For example, it may be a straight line in which the thickness of the insulating portion of the recessed portion is constant, or it may be curved or stepped by changing the thickness. From the viewpoint of ensuring the strength of the circuit sheet, the shape of the recessed portion is preferably a straight line or a curved shape that is convex in the direction opposite to the element mounting surface.

An example of the configuration of the circuit sheet of the present disclosure will be described with reference to the drawings.
FIG. 4A is a diagram schematically showing a cross section of the circuit sheet of the present disclosure. The circuit sheet 170 shown in FIG. 4A includes a circuit 41 and an insulating portion 42 provided between the circuits 41, and the insulating portion 42 is recessed on the element mounting surface.

The degree of denting of the insulating portion on the element mounting surface is not particularly limited. For example, when the maximum value of the height difference between the insulating portion on the element mounting surface and the adjacent circuit is d and the thickness of the circuit is D, the ratio (d / D) of d to D is 0.0025 to 0. When it is 5, it is easy to secure the bending strength of the circuit sheet in the insulating portion, and when it is 0.0025 to 0.25, it is easier to secure the strength of the circuit sheet, and in a later step, the circuit board is passed through the insulating layer. There is a tendency to easily suppress damage to the circuit sheet when pressure-bonding.
When the ratio (d / D) of d to D is 0.0025 to 0.025, it is easy to secure the strength of the circuit sheet, it is easy to secure the symmetry in the thickness direction of the circuit sheet, and the warp of the circuit sheet can be reduced. There is a tendency. Therefore, when the circuit sheet is pressure-bonded through the insulating layer in a later step, it can be adhered well.
The ratio of d to D (d / D) is more preferably 0.003 to 0.01.
In some embodiments, the maximum value d of the height difference between the insulating portion on the element mounting surface and the adjacent circuit may be in the range of 5 μm to 50 μm.

It is preferable that the surface of the circuit sheet opposite to the element mounting surface is flatter than the element mounting surface. As a result, when the surface opposite to the element mounting surface is brought into contact with the insulating layer, it is easy to adhere to the insulating layer, and good insulating properties tend to be obtained. Further, when it is adhered to the heat radiating member via the insulating layer, it is easily adhered to the insulating layer, and good insulating properties tend to be obtained.
In the present invention, "the surface opposite to the element mounting surface is flatter than the element mounting surface" means that the maximum value of the height difference between the insulating portion and the adjacent circuit on the surface opposite to the element mounting surface is d'. (Plus means that it is recessed from the circuit surface, minus means that it is protruding), and when the thickness of the circuit is D, the ratio of d'to D (d'/ D) is ( It means that the condition of d / D)>(d'/ D) is satisfied.
Specifically, when (d'/ D) is −0.005 to 0.005 within a range not exceeding (d / D), it is preferable because it is easy to secure the adhesiveness between the circuit sheet and the insulating layer. The range of −0.0025 to 0.0025 is more preferable because it is possible to reduce the entrainment of air bubbles and the like during crimping between the circuit sheet and the insulating layer. In addition, since the surface opposite to the element mounting surface is flatter than the element mounting surface, there is an advantage that the front and back surfaces of the circuit sheet can be discriminated.
In some embodiments, the maximum value d'of the height difference between the insulating portion and the adjacent circuit on the surface opposite to the device mounting surface may be in the range of -5 μm to 5 μm, and may be in the range of 0 μm to 5 μm. Is preferable.

The circuit sheet preferably has a portion where the circuit and the insulating portion overlap in the thickness direction on the surface opposite to the element mounting surface.
The circuit obtained by processing a metal plate or the like may have a portion having insufficient thickness due to wear during cutting or the like. Therefore, when the circuit is arranged on the insulating layer, a gap is generated between the circuits, and there is a possibility that the circuit cannot be sufficiently adhered.
Since the insulating material enters the part where the thickness of the circuit is insufficient and overlaps with the insulating part in the thickness direction, the formation of a gap between the circuit and the insulating layer is suppressed, and the adhesiveness with the insulating layer is suppressed. Is improved. Therefore, when the circuit sheet is bonded to the insulating layer, it is important that the portion of the circuit sheet where the circuit and the insulating portion overlap in the thickness direction is provided before bonding to the insulating layer.

The width of the portion where the circuit and the insulating portion overlap in the thickness direction is preferably 5 μm to 100 μm, preferably 8 μm to 70 μm, from the viewpoint of adhesiveness between the circuit sheet and the insulating layer and heat dissipation when used as a circuit board. Is more preferable. The portion where the circuit and the insulating portion overlap in the thickness direction may be a portion where the insulating layer is inserted on the surface side opposite to the element mounting surface.

FIG. 4B is a diagram schematically showing a cross section of a portion where the circuit of the circuit sheet and the insulating portion overlap in the thickness direction. As shown in FIG. 4B, the circuit sheet 170 has a portion 43 in which the circuit 41 and the insulating portion 42 overlap in the thickness direction on the surface opposite to the element mounting surface.

The portion 43 in which the circuit 41 and the insulating portion 42 overlap in the thickness direction is also formed in a portion where the thickness of the circuit 41 is insufficient, for example, when the insulating material is filled between the circuits 41 to form the insulating portion 42. It can be formed by filling an insulating material.

At least a part of the circuit is exposed on the element mounting surface side and the insulating layer side. The thickness of the circuit is not particularly limited and can be selected according to the application of the circuit sheet and the like. From the viewpoint of increasing the current of the circuit, the thickness of the circuit is preferably 350 μm or more, more preferably 500 μm or more from the viewpoint of corresponding to the larger current, and 1000 μm or more from the viewpoint of heat dissipation. Is particularly preferred. From the viewpoint of reducing the weight and height of the circuit sheet, the thickness of the circuit is preferably 5000 μm or less, and more preferably 3500 μm or less from the viewpoint of processability of the circuit. From the viewpoint of crimping the circuit sheet, the thickness of the circuit is more preferably 3000 μm or less. When the thickness of the circuit is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.
When a part of the circuit is embedded in an adjacent member such as an insulating layer, the thickness of the embedded part is also included in the thickness of the circuit.

The width of the circuit when observing the element mounting surface of the circuit sheet is not particularly limited, and may be selected depending on the application of the circuit sheet and the like. For example, the width of the circuit may be 100 μm to 100 mm. When the circuit is curved or stepped and the width is not constant, the measured value at the narrowest position is taken as the above value.
The circuit may consist of one independent pattern (all circuits in the pattern are continuous) or two or more independent patterns. When the circuit sheet is arranged on the insulating layer, the independent patterns may be arranged on the independent insulating layer or may be arranged on the same insulating layer. When the width of the circuit is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.

The circuit can be obtained, for example, by processing a metal plate into a circuit state having a desired shape. The processing method is not particularly limited, and can be performed by a known method such as punching, cutting, or etching.
Examples of the metal include copper, silver, chromium copper, tungsten copper, nickel, nickel-plated copper, aluminum, and aluminum whose surface is modified to alumite. From the viewpoint of conductivity and heat dissipation, it is preferable to contain copper.

The width of the insulating portion when observing the element mounting surface of the circuit sheet is not particularly limited, and may be selected according to the application of the circuit sheet and the like. For example, the width of the insulating portion may be 100 μm to 100 mm. When the insulating portion is curved or stepped and the width is not constant, the measured value at the narrowest position is taken as the above value.

Examples of the insulating material used for forming the insulating portion of the circuit sheet include materials containing resins such as epoxy resin, phenol resin, urea resin, melamine resin, urethane resin, silicone resin, unsaturated polyester resin, and acrylic resin. The resin contained in the insulating material may be one kind or two or more kinds. The insulating material may contain components other than the resin, such as an inorganic filler, if necessary.

From the viewpoint that the insulating portion is recessed on the element mounting surface of the circuit sheet, it is preferable that the insulating portion is formed by using an insulating material whose volume shrinks when cured.

<Modification example of the circuit sheet of the fifth embodiment>
As a modification of the circuit sheet of the fifth embodiment, at least a part of the element mounting surface on which the element is mounted and the element mounting in the circuit are provided between the plurality of circuits and the plurality of circuits. It has an insulating portion that holds relative positions of the plurality of circuits so that at least a part of the surface opposite to the surface is exposed, and the surface of the insulating portion on the device mounting surface side is the circuit. It is a circuit sheet that is recessed with respect to the element mounting surface of the above.
Since the surface of the insulating portion on the element mounting surface side is recessed with respect to the element mounting surface of the circuit, the workability of element mounting is improved. A preferred embodiment of the above-described modification is the same as that of the circuit sheet of the fifth embodiment.

<Manufacturing method of circuit sheet of the fifth embodiment>
The method for manufacturing a circuit sheet according to a fifth embodiment of the present disclosure includes a step of filling an insulating material between the circuits with a protective film attached to one surface of the sheet-shaped circuit, and a step of curing the insulating material. It has a process of making it, and in this order,
The protective film is a method for manufacturing a circuit sheet, which is deformable with volume shrinkage due to curing of the insulating material.

In the above method, an insulating material is filled between sheet-shaped circuits and cured to form an insulating portion made of a cured product of the insulating material. Further, by utilizing the phenomenon that the insulating material shrinks in volume due to curing, the cured product (insulating portion) of the insulating material is formed in a recessed state on the element mounting surface. More specifically, by using a protective film attached to the circuit that can be deformed as the insulating material shrinks due to hardening, the volume shrinkage of the insulating material is not hindered and the insulating portion in a recessed state is used. Can be formed.

In the above method, the surface to which the protective film of the circuit is attached may be the element mounting surface of the circuit sheet.
The circuit and insulating material used in the above method may be the circuit and insulating material used in the circuit sheet of the present disclosure described above, respectively.
The method of filling the insulating material between the circuits and the method of curing are not particularly limited, and a known method can be used.

The protective film used in the above method is not particularly limited as long as it can be deformed by volume shrinkage due to curing of the insulating material. Specifically, various resin films such as PET film, polyimide film, and polyamide film can be used. When heating is required in a later step, a polyimide film or a polyamide film is more preferable from the viewpoint of heat resistance.

From the viewpoint of preventing the protective film from peeling off from the circuit during filling and curing of the insulating material, the surface of the protective film to be attached to the circuit may have adhesiveness. For example, a layer containing an adhesive such as an acrylic adhesive, a urethane adhesive, or a silicone adhesive may be formed on the surface of the protective film to be attached to the circuit. By having the pressure-sensitive adhesive, the insulating material can be suppressed from entering between the circuit and the pressure-sensitive adhesive, and the element can be mounted in a good state.

From the viewpoint of yielding to volume shrinkage due to curing of the insulating material, the flexural modulus of the protective film is preferably 200 MPa to 20 GPa, and more preferably 1 GPa to 15 GPa from the viewpoint of ease of controlling the volume shrinkage amount. From the viewpoint of ease of peeling of the protective film, the flexural modulus of the protective film is more preferably 3 GPa to 9.5 GPa.
The flexural modulus of the protective film is measured according to JIS K7171.

The thickness of the protective film is not particularly limited, but the thickness of the protective film (including the thickness of the adhesive layer if it has an adhesive layer) is preferably 10 μm to 1 mm, preferably 25 μm to 500 μm from the viewpoint of handling. It is more preferable because it is easy to suppress twisting and twisting of the protective film and it is easier to handle, and it is more preferable that the thickness is 25 μm to 120 μm because it is easy to control the amount of volume shrinkage due to curing of the insulating material.

In the above method, it is preferable that the insulating material is filled and cured in a state where a member that does not deform due to volume shrinkage due to the curing of the insulating material is in contact with the surface opposite to the surface to which the protective film of the circuit is attached. .. The surface on the side where such a member comes into contact is less likely to have a dented state of the cured product of the insulating material, and can be made flatter than the surface to which the protective film is attached.

In the present disclosure, "contacting a member" means bringing the member into contact with the circuit so that it can be easily separated from the circuit after the step of curing the insulating material. Examples of the member include a mold having a flat surface in contact with the circuit.

It is preferable that the protective film attached to one surface of the circuit has lower elasticity (easily deformed) than the member that abuts on the opposite surface. By doing so, the surface on the side to which the protective film is attached can be selectively made into a state in which the cured product of the insulating material is recessed. Further, the protective film and the member can be more easily removed from the obtained circuit sheet, and the occurrence of circuit breakage or the like at the time of removal can be suppressed.

The surface where the sheet-shaped circuit and the member are in contact may be such that the entire surface of the circuit is in contact with the member, or a part of the surface is not in contact with the member and there is a gap between them. When there is a gap between the circuit and the member, it is preferable that the gap is also filled with a part of the insulating material filled between the circuits. As a result, as shown in FIG. 4B, a portion where the circuit and the insulating material overlap in the thickness direction of the circuit sheet is formed, and the surface of the obtained circuit sheet is further flattened.

<Circuit board of the fourth embodiment>
The circuit board of the present disclosure is in contact with the circuit sheet of the fifth embodiment of the present disclosure described above, an insulating layer arranged so as to be in contact with a surface opposite to the element mounting surface of the circuit sheet, and the insulating layer. It has a heat radiating member to be arranged.

The types of the insulating layer and the heat radiating member used for the circuit board are not particularly limited, and can be selected from those generally used for the circuit board.

The thickness of the insulating layer is not particularly limited and can be selected according to the application of the circuit board. From the viewpoint of ensuring sufficient insulating properties, the thickness of the insulating layer is preferably 50 μm or more, more preferably 100 μm or more, and further preferably 150 μm or more.

From the viewpoint of ensuring sufficient heat dissipation, the thickness of the insulating layer is preferably 500 μm or less, more preferably 300 μm or less, and further preferably 250 μm or less.

<Manufacturing method of circuit board of the fourth embodiment>
The method for manufacturing the circuit board of the fourth embodiment of the present disclosure includes the circuit sheet of the fifth embodiment described above, an insulating layer arranged on a surface opposite to the element mounting surface of the circuit sheet, and a heat radiating member. And have a step of pressurizing the laminated body in the state of arranging in this order.
The pressurization is a method for manufacturing a circuit board, in which a cushioning material deformable by the pressurization is arranged on an element mounting surface of the circuit sheet.

In the circuit sheet used in the above method, since the insulating portion is recessed on the element mounting surface, the pressurization may not be performed evenly.
In the above method, by arranging the cushion material on the element mounting surface of the circuit sheet, the pressure applied to the element mounting surface is dispersed, and the circuit sheet, the insulating layer and the heat radiating member can be sufficiently adhered.

The cushioning material used in the above method is not particularly limited as long as it is a cushioning material that can be deformed by pressurization, and examples thereof include rubbers such as fluororubber and silicon rubber, and thermoplastic resins or elastomers.

The method of pressurizing the laminate in the above method is not particularly limited, and can be selected from the methods generally performed in the circuit board manufacturing process. As a pressurizing method, roll laminating, flat plate laminating, quick press, flat plate press and the like are used, and the pressure may be applied at normal pressure or in vacuum. The pressurizing pressure is preferably 0.1 MPa to 10 MPa because it is easy to control the pressure, and 0.2 MPa to 8 MPa is preferable because it is easy to secure the adhesiveness with the adhesive layer, and 1 MPa to 8 MPa is preferable. It is more preferable because it is possible to suppress the entrainment of air bubbles and the like between the layers and it is easy to secure the insulating property.

When pressurizing the laminate, the laminate may be heated at the same time. The heating temperature is preferably 40 ° C. to 300 ° C. from the viewpoint of ensuring the adhesiveness between the insulating layer and the circuit and the insulating layer and the heat radiating member, and 130 ° C. to 250 ° C. from the viewpoint of curing the adhesive layer. It is more preferable that the temperature is 150 ° C. to 230 ° C. from the viewpoint of allowing the cushion material to sufficiently follow the recessed portion of the circuit sheet.

<Circuit sheet of the sixth embodiment>
The circuit sheet of the sixth embodiment of the present disclosure includes a circuit and an insulating portion provided between the circuits.
A circuit sheet in which the surface roughness A of at least a part of the surface of the circuit in contact with the insulating portion is larger than the surface roughness B of the element mounting surface of the circuit.

The circuit sheet having the above configuration is excellent in reliability because peeling between the circuit and the insulating part is unlikely to occur. Further, since the surface roughness of the element mounting surface is relatively small, the element mounting process can be performed satisfactorily.

The circuit sheet may further include an insulating layer provided on the surface opposite to the element mounting surface of the circuit.
When the circuit sheet has an insulating layer, the insulating portion and the insulating layer may be different members or the same member. As an example of the case where the insulating portion and the insulating layer are the same member, the insulating layer is formed between the circuits to form the insulating portion, or the insulating layer is formed so as to cover the lower surface of the circuit. There is a state of being.

An example of the configuration of the circuit sheet of the present disclosure will be described with reference to the drawings.
FIG. 5A is a diagram schematically showing a cross section of the circuit sheet of the present disclosure. The circuit sheet 180 shown in FIG. 5A includes a circuit 51, an insulating portion 52 provided in a space between the circuits 51, and an insulating layer 53 provided on a surface opposite to the element mounting surface of the circuit 51. The surface (side surface) of the circuit 51 in contact with the insulating portion 52 has a larger surface roughness than the element mounting surface, and peeling from the adjacent insulating portion 52 is less likely to occur. Further, the surface (lower surface) opposite to the element mounting surface of the circuit 51 and in contact with the insulating layer 53 also has a larger surface roughness than the element mounting surface, and peeling from the insulating layer 53 is less likely to occur.

Although the insulating portion 52 and the insulating layer 53 are described as different members in FIG. 5A, the insulating portion 52 and the insulating layer 53 may be the same member as described above. Further, in FIG. 5A, the surface roughness of both the side surface and the lower surface of the circuit 51 is larger than the surface roughness of the element mounting surface, but only the surface roughness of the side surface may be larger than the surface roughness of the element mounting surface.

The side surface of the circuit may satisfy the condition of surface roughness A as a whole, or only a part of the side surface may satisfy the condition of surface roughness A. From the viewpoint of achieving good insulation and heat dissipation, it is preferable that the surface roughness A of at least the portion of the side surface of the circuit connected to the lower surface of the circuit is larger than the surface roughness B of the element mounting surface of the circuit. As a result, peeling between the circuit and the insulating layer is further suppressed, good insulating properties are maintained, and heat is well conducted to the heat radiating member arranged via the insulating layer.
From the above viewpoint, the most preferable aspect of the circuit is that the entire side surface satisfies the condition of surface roughness A. As a result, the adhesiveness between the side surface and the insulating portion can be ensured over the entire region, so that peeling can be further suppressed.

The surface roughness C of the surface opposite to the element mounting surface of the circuit (the surface in contact with the insulating layer) may be the same as or different from the surface roughness A of the circuit. From the viewpoint of suppressing peeling between the circuit and the insulating layer, the surface roughness C of the surface opposite to the element mounting surface of the circuit (the surface in contact with the insulating layer) is larger than the surface roughness B of the element mounting surface of the circuit. Is preferable.

In the present disclosure, the surface roughness of the circuit may be expressed by the arithmetic mean roughness (Ra) defined by JIS B 0601 (2001).
The surface roughness A represented by Ra is preferably 0.3 μm or more, more preferably 0.4 μm or more, and further preferably 0.6 μm or more from the viewpoint of adhesiveness. It is particularly preferable that the thickness is 0.0 μm or more. From the viewpoint of withstand voltage characteristics, the surface roughness A expressed in Ra is preferably 5.0 μm or less, and more preferably 2.5 μm or less. Further, Ra is preferably in the above range and the specific surface area is preferably 1.3 or more, more preferably 1.4 or more, and further preferably 1.6 or more. When the value of the specific surface area is large, the adhesive area per unit area becomes large, and the adhesiveness can be improved. From the viewpoint of withstand voltage characteristics, the specific surface area is preferably 5.0 or less, and more preferably 3.0 or less.

The "specific surface area" in the present disclosure is a value obtained by calculating the three-dimensional surface area B in the measurement area A and calculating the B / A. The three-dimensional surface area B can be calculated by measuring the surface profile of a predetermined measurement area A (for example, 10000 μm ^{2) of the measurement surface with a commercially available laser microscope.}

The surface roughness B represented by Ra is preferably less than 0.3 μm, more preferably 0.2 μm or less, and further preferably 0.15 μm or less from the viewpoint of device mounting.

The surface roughness C when expressed in Ra is preferably 0.3 μm or more, more preferably 0.4 μm or more, further preferably 0.6 μm or more, and 1.0 μm or more. Is particularly preferred. From the viewpoint of withstand voltage characteristics, the surface roughness C when expressed in Ra is preferably 5.0 μm or less, and more preferably 2.5 μm or less. Further, Ra is preferably in the above range and the specific surface area is preferably 1.3 or more, more preferably 1.4 or more, and further preferably 1.6 or more. When the value of the specific surface area is large, the adhesive area per unit area becomes large, and the adhesiveness can be improved. From the viewpoint of withstand voltage characteristics, the specific surface area is preferably 5.0 or less, and more preferably 3.0 or less.

The relative ratio of the surface roughness A and the surface roughness B when expressed in Ra is not particularly limited. For example, the surface roughness A may be more than 1.0 times to 100 times the surface roughness B.
The relative ratio of the surface roughness C and the surface roughness B when expressed in Ra is not particularly limited. For example, the surface roughness A may be more than 1.0 times to 100 times the surface roughness B.

The thickness of the circuit is not particularly limited and can be selected according to the application of the circuit sheet and the like. From the viewpoint of increasing the current of the circuit, the thickness of the circuit is preferably 350 μm or more, and when there is a step of roughening the side surface of the circuit, 400 μm from the viewpoint of handleability and area control of the roughened portion. The above is more preferable, 500 μm or more is further preferable, and 1000 μm or more is particularly preferable from the viewpoint of heat dissipation. From the viewpoint of weight reduction and height reduction, the thickness of the circuit may be 5000 μm or less. When the thickness of the circuit is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.
When a part of the circuit is embedded in the insulating layer, the thickness of the embedded part is also included in the thickness of the circuit.

The circuit can be obtained, for example, by processing a metal plate into a circuit state having a desired shape. The processing method is not particularly limited, and can be performed by a known method such as punching, cutting, or etching.
Examples of the metal include copper, silver, chromium copper, tungsten copper, nickel, nickel-plated copper, aluminum, and aluminum whose surface is modified to alumite. From the viewpoint of conductivity, it is preferable to contain copper.

The thickness of the insulating layer is not particularly limited and can be selected according to the application of the circuit board manufactured by using the circuit sheet. From the viewpoint of ensuring sufficient insulation, the thickness of the insulating layer is preferably 100 μm or more, more preferably 150 μm or more from the viewpoint of ensuring the strength of the insulating layer against thermal shock, and insulation during crimping. From the viewpoint of layer handleability, it is more preferably 200 μm or more.

The insulating portion and the insulating layer are formed of a material having electrical insulating properties (insulating material).
Examples of the insulating material include epoxy resin, phenol resin, urea resin, melamine resin, urethane resin, silicone resin, unsaturated polyester resin, acrylic resin and the like. The resin contained in the insulating material may be one kind or two or more kinds. The insulating material may contain components other than the resin, such as an inorganic filler, if necessary.

The resin contained in the insulating material forming the insulating portion and the resin contained in the insulating material forming the insulating layer may be of the same type (for example, both are epoxy resins) or different types. From the viewpoint of the adhesiveness between the insulating portion and the insulating layer, it is preferable that the resin contained in the insulating material forming the insulating portion and the resin contained in the insulating material forming the insulating layer are the same material.

The circuit sheet may be in a state where the element mounting surface is covered with plated metal. By coating the element mounting surface of the circuit sheet with plated metal, the surface roughness of the element mounting surface is reduced. As a result, the surface roughness A of the circuit can be made larger than the surface roughness B of the circuit.

The element mounting surface may be coated with the plated metal, for example, after the step of roughening the surface (including the element mounting surface and the side surface) of the sheet-shaped circuit.

<Manufacturing method of circuit sheet of the sixth embodiment>
The method for manufacturing a circuit sheet according to the sixth embodiment of the present disclosure includes a step of roughening the surface of the circuit with a protective member attached to one surface of the sheet-shaped circuit.
This is a method for manufacturing a circuit sheet, which comprises a step of forming an insulating portion between the circuits in this order.

In the above method, the surface of the circuit is roughened with the protective member attached to one surface of the sheet-shaped circuit. As a result, the surface of the circuit (that is, the surface including the portion where the circuit is in contact with the insulating portion) excluding the portion to which the protective member of the circuit is attached (that is, the element mounting surface) is roughened. As a result, it is possible to obtain a circuit sheet in which the surface roughness A of at least a part of the surface (side surface of the circuit) in contact with the insulating portion of the circuit is larger than the surface roughness B of the element mounting surface of the circuit.

The method of roughening the surface of the circuit in the above method is not particularly limited. For example, it can be selected from known methods such as chemical treatment, laser irradiation, and blast treatment. From the viewpoint of sufficiently roughening the side surface of the circuit, chemical treatment is preferable.

In the above method, the type of the protective member attached to one surface of the circuit is not particularly limited, and can be selected depending on the method of roughening the surface of the circuit and the like. When the surface of the circuit is brought into contact with a chemical solution to roughen it, it is preferable to use a protective member having resistance to the chemical solution used.
The protective member may be attached to only one side of the circuit or may be attached to both sides of the circuit. From the viewpoint of improving the adhesiveness of the insulating layer and the insulating portion to the circuit, it is preferable that the insulating layer and the insulating portion are attached only to one surface of the circuit (that is, the element mounting surface). As a result, in addition to the side surface of the circuit, the surface in contact with the insulating layer of the circuit is also roughened, and the adhesiveness of the insulating layer to the circuit as well as the adhesiveness to the insulating portion can be improved.

The removal of the protective member affixed to one side of the circuit may be performed before the step of forming the insulation between the circuits or after the step of forming the insulation between the circuits. good.

In the above method, the method of forming an insulating portion between the circuits is not particularly limited. For example, the insulating material used for forming the insulating portion of the circuit sheet of the present disclosure described above may be filled, and if necessary, a hardening treatment or the like may be performed to form the insulating material.

The above method may include a step of arranging the insulating layer on the surface opposite to the surface to which the protective member of the circuit is attached. This makes it possible to manufacture a circuit sheet in which an insulating layer is arranged on a surface opposite to the element mounting surface of the circuit.

The arrangement of the insulating layer is preferably performed after the step of roughening the surface of the circuit, and even if it is performed after the step of forming the insulating portion between the circuits, at the same time as the step of forming the insulating portion between the circuits. It may be done.
If the placement of the insulation layer is done after the step of roughening the surface of the circuit, the placement of the insulation layer can ensure good adhesion between the circuit and the insulation layer after the step of forming the insulation between the circuits. In this case, the circuit sheet in which the insulating layer is formed between the circuits and the insulating layer can be crimped, so that the handling property is excellent.
When the arrangement of the insulating layer is performed at the same time as the step of forming the insulating portion between the circuits, the arrangement of the insulating layer and the formation of the insulating portion can be performed at the same time, so that the work efficiency is excellent.

By performing the step of arranging the insulating layer after the step of forming the insulating portion between the circuits, for example, a circuit sheet in which the insulating portion and the insulating layer are different members can be manufactured.
By performing the step of arranging the insulating layer at the same time as the step of forming the insulating portion between the circuits, for example, a circuit sheet in which at least a part of the insulating portion and the insulating layer is the same member can be manufactured.

The details and preferred embodiments of the circuit, insulating portion, and insulating layer used in the above method may be the same as the details and preferred embodiments of the circuit, insulating portion, and insulating layer in the circuit sheet described above.

<Circuit board of the fifth embodiment>
The circuit board of the fifth embodiment of the present disclosure is a circuit board having the circuit sheet of the sixth embodiment described above and a heat radiating member arranged on a surface opposite to the element mounting surface of the circuit sheet.

The circuit board is excellent in reliability because peeling does not easily occur between the circuit and the insulating portion.
In the circuit board, it is preferable that an insulating layer is arranged between the circuit and the heat radiating member.
The details and preferred embodiments of the circuit sheet used in the circuit board are the same as the details and preferred embodiments of the circuit sheet, circuit, insulating portion and insulating layer of the present disclosure described above.
The type of heat radiating member used for the circuit board is not particularly limited, and can be selected from those generally used for the circuit board. For example, it may be metal, ceramics or the like, and aluminum or copper is preferable from the viewpoint of heat dissipation.

<Manufacturing method of circuit board of the fifth embodiment>
In the method for manufacturing the circuit board of the fifth embodiment of the present disclosure, the circuit sheet of the sixth embodiment described above and the heat radiating member arranged on the surface opposite to the element mounting surface of the circuit sheet are arranged in this order. It is a method of manufacturing a circuit board, which comprises a step of pressurizing a laminated body in a state.

According to the above method, it is possible to manufacture a circuit board having excellent reliability because peeling is unlikely to occur between the circuit and the insulating portion.
The details and preferred embodiments of the circuit sheet used in the method for manufacturing a circuit board are the same as the details and preferred embodiments of the circuit sheet, circuit, insulating portion and insulating layer of the present disclosure described above.
The type of heat radiating member used for the circuit board is not particularly limited, and can be selected from those generally used for the circuit board. For example, it may be metal, ceramics or the like, and aluminum or copper is preferable from the viewpoint of heat dissipation.

<Circuit sheet with case of the seventh embodiment>
The circuit sheet with a case of the seventh embodiment of the present disclosure includes a circuit sheet including a circuit and an insulating portion provided between the circuits, and a case arranged on a heating element mounting surface of the circuit sheet. ..

In the conventional method of manufacturing a circuit board using a circuit sheet, a heating element is mounted in a state where the circuit sheet is arranged on a base plate having heat dissipation property via an insulating layer. On the other hand, in the method of manufacturing a circuit board using the circuit sheet with a case of the present disclosure, the heating element can be mounted in a state where the circuit sheet is not provided with the insulating layer. Thereby, the circuit board can be manufactured regardless of the heat resistance of the insulating layer.

The circuit sheet with a case of the present disclosure is provided between a plurality of circuits and the plurality of circuits, and in the circuit, at least a part of a heating element mounting surface on which a heating element is mounted and the heating element mounting surface. A circuit sheet including an insulating portion that holds relative positions of the plurality of circuits so that at least a part of the surface on the opposite side is exposed, and a case arranged on the heating element mounting surface of the circuit sheet. And may be configured.

The method of manufacturing a circuit board using the circuit board with a case of the present disclosure will be described based on a comparison with a method of manufacturing a circuit board using a conventional circuit board.

FIG. 6A shows an example of a manufacturing process of a circuit board using the circuit sheet with a case of the present disclosure.
The circuit sheet 190 with a case shown in FIG. 6A (a) includes a circuit 61, a circuit sheet having an insulating portion 62 provided between the circuits 61, and a case 63 arranged on a heating element mounting surface of the circuit sheet. It has. The case 63 is arranged so as to surround the area on which the heating element 64 is mounted.

Next, as shown in FIG. 6A (b), the heating element 64 is mounted on the circuit 61 of the circuit sheet 190 with a case. At this time, heating for melting the solder used for mounting the heating element is performed at, for example, about 300 ° C. After that, as shown in FIG. 6A (c), the case 63 and the heating element 64 are connected by the bonding wire 65.

Next, as shown in FIG. 6A (d), a sealing material is supplied to the portion of the circuit sheet 190 with a case on the heating element mounting surface surrounded by the case 63 to form the sealing portion 66.

Next, as shown in FIG. 6A (e), the insulating layer 67 and the heat radiating member 68 are arranged on the side opposite to the heating element mounting surface of the circuit sheet 190 with a case to obtain a circuit board.

In FIG. 6A, the step shown in FIG. 6A (e) is performed after the step shown in FIG. 6A (d), but the step shown in FIG. 6A (d) may be performed after the step shown in FIG. 6A (e).

FIG. 6B shows an example of a circuit board manufacturing process using a conventional circuit sheet.
The circuit sheet 70 shown in FIG. 6B (a) has a circuit 71 and an insulating portion 72 in common with the present disclosure, but the case 73 is provided on the base plate 80 instead of the circuit sheet 70. It differs from the present disclosure in that it is.

As shown in FIG. 6B (a), the circuit sheet 70 is mounted on the base plate 80 via the insulating layer 77. At this time, heating for melting the solder used for mounting the circuit sheet 70 is performed, for example, at about 300 ° C.

Next, as shown in FIG. 6B (b), the heating element 74 is mounted on the circuit 71 of the circuit sheet 70. At this time, heating for melting the solder used for mounting the heating element is performed at, for example, about 300 ° C. After that, as shown in FIG. 6B (c), the case 73 and the heating element 74 are connected by the bonding wire 75.

Next, as shown in FIG. 6B (d), the sealing material is supplied to the portion surrounded by the case 73 arranged on the base plate 80 to form the sealing portion 76.

Next, as shown in FIG. 6B (e), the heat radiating member 78 is arranged on the surface of the base plate 80 opposite to the surface on which the circuit sheet is mounted via a heat conductive sheet 79 such as TIM (Thermal Interface Material). , The circuit board is obtained.

As described above, in the conventional circuit board manufacturing method, heating is performed at the solder melting temperature with the insulating layer arranged between the base plate and the circuit sheet. On the other hand, in the circuit board manufacturing method of the present disclosure, the insulating layer is arranged after heating at the solder melting temperature. Therefore, for example, it becomes possible to use a material that could not be used for the reason of heat resistance as an insulating layer.

Further, the circuit board obtained by using the circuit sheet with a case of the present disclosure can reduce the number of members having thermal resistance such as an insulating layer and a solder layer in the thickness direction, which is also advantageous in terms of heat dissipation. Further, the base plate used for the conventional circuit board can be omitted, which is advantageous in terms of productivity.

The circuit constituting the circuit sheet with a case can be obtained, for example, by processing a metal plate into a circuit state having a desired shape. The processing method is not particularly limited, and can be performed by a known method such as punching, cutting, or etching.

Examples of the metal include copper, silver, chromium copper, tungsten copper, nickel, nickel-plated copper, aluminum and the like. From the viewpoint of conductivity and heat dissipation, it is preferable to contain copper.

The thickness of the circuit is not particularly limited and can be selected according to the application of the circuit board and the like. From the viewpoint of increasing the current of the circuit board, the thickness of the circuit is preferably 350 μm or more, more preferably 400 μm or more, further preferably 500 μm or more, and particularly preferably 1000 μm or more. .. The thickness of the circuit may be 5000 μm or less.
When the thickness varies depending on the location of the circuit, the arithmetic mean value of the measured values obtained at the five arbitrarily selected locations may be used as the above value. The thickness of the circuit means the thickness of the circuit itself, and when a part of the circuit is embedded in an adjacent member, the thickness of the embedded portion is also included in the thickness of the circuit.

The width and length of the circuit are not particularly limited and may be selected according to the application of the circuit board and the like. For example, the width and length of the circuit may be 350 μm to 70,000 μm, respectively. When the width or length differs depending on the location of the circuit, the arithmetic mean value of the measured values obtained at the five arbitrarily selected locations may be used as the above value.

The insulating portion constituting the circuit sheet with a case can be formed, for example, by filling the circuit of the circuit sheet with an insulating material having fluidity and curing the insulating material. Examples of the insulating material include materials containing resins such as epoxy resin, phenol resin, urea resin, melamine resin, urethane resin, silicone resin, unsaturated polyester resin, acrylic resin, and polyphenylene sulfide resin. The resin contained in the insulating material may be one kind or two or more kinds. The insulating material may contain components other than the resin, such as an inorganic filler, if necessary.

In the case constituting the circuit sheet with a case, for example, the portion connected to the heating element by the bonding wire may be made of a conductive material, and the other part may be made of an insulating material. Since the case is exposed to heating during mounting of the heating element and formation of the sealing portion, it is preferable that the case has sufficient heat resistance to these heatings.

Examples of the insulating material constituting the case include the above-mentioned resin-containing material as the insulating material for forming the insulating portion of the circuit sheet. The resin contained in the insulating material may be one kind or two or more kinds. The insulating material may contain components other than the resin, such as an inorganic filler, if necessary.

The case may be placed on the circuit of the circuit sheet or on the insulation. In some embodiments, the case is placed on top of the circuit on the circuit sheet.
By arranging the case on the circuit sheet, the manufacturing process can be simplified as compared with the case where the case is arranged on the heat radiating member under the circuit sheet, for example, and the circuit sheet and the heat radiating base material via the insulating layer can be simplified. Is easy to integrate. Alternatively, as compared with the case where the case is arranged in the insulating layer on the lower side of the circuit sheet, it is less likely to be deformed during the work, and the shape of the circuit board can be easily maintained.
The case may be fixed to the circuit sheet using a silicone adhesive or the like. The position where the case is arranged on the heating element mounting surface of the circuit sheet is not particularly limited, and can be set according to the shape of the circuit board and the like.

The circuit sheet with a case may further include a heating element arranged on the heating element mounting surface. The type of the heating element is not particularly limited, and may be selected from the components generally used for the circuit board. In some embodiments, the heating element is placed on the circuit using a bonding material such as solder.
The heating element may be the above-mentioned element.

<Circuit package>
The circuit package of the present disclosure includes a circuit sheet including a circuit and an insulating portion provided between the circuits, a case arranged on the heating element mounting surface of the circuit sheet, and heat generation arranged on the circuit. It includes a body and a sealing portion arranged in a portion surrounded by the case.
That is, the circuit package of the present disclosure is in a state in which a sealing portion is formed in a portion of the circuit sheet with a case surrounded by a case.

The type of sealing material used to form the sealing portion is not particularly limited. Examples thereof include materials containing resins such as epoxy resin, phenol resin, urea resin, melamine resin, urethane resin, silicone resin, unsaturated polyester resin, acrylic resin and polyphenylene sulfide resin. The resin contained in the sealing material may be one kind or two or more kinds. The encapsulant may contain components other than the resin, such as an inorganic filler, if necessary.

<Circuit board of the sixth embodiment>
The circuit board of the sixth embodiment of the present disclosure includes the circuit package of the present disclosure described above, and an insulating layer and a heat radiating member arranged on a surface opposite to the heating element mounting surface of the circuit package.

The type of insulating layer is not particularly limited. For example, it may contain a resin. The resin contained in the insulating layer may be one type or two or more types. The insulating layer may contain a component other than the resin such as a filler, if necessary.

The thickness of the insulating layer is not particularly limited. From the viewpoint of ensuring sufficient insulating properties, the larger the thickness of the insulating layer, the more preferable. For example, the thickness of the insulating layer is preferably 60 μm or more, more preferably 90 μm or more, and further preferably 120 μm or more.

From the viewpoint of ensuring sufficient heat dissipation, the smaller the thickness of the insulating layer, the more preferable. For example, the thickness of the insulating layer is preferably 230 μm or less, more preferably 210 μm or less, and even more preferably 190 μm or less.

The type of the heat radiating member is not particularly limited, and may be selected from those generally used as the heat radiating member of the circuit board. For example, it may be a member made of a metal such as aluminum, iron, or copper, or ceramics, which has excellent heat dissipation.

On the circuit board, one surface of the circuit is in contact with the heating element, and the other surface is in contact with the insulating layer. That is, the circuit communicates the heating element and the insulating layer. As a result, it is possible to obtain a structure in which the insulation between the circuits is sufficiently ensured.

<Circuit board manufacturing method A>
The circuit board manufacturing method A of the present disclosure includes a step of forming a sealing portion in a portion of the circuit sheet with a case surrounded by the case described above, and a step of forming a sealing portion.
It includes a step of arranging an insulating layer and a heat radiating member on the surface opposite to the heating element mounting surface of the circuit sheet with a case.

In the above method, the order of the step of forming the sealing portion and the step of arranging the insulating layer and the heat radiating member is not particularly limited, and any of them may be carried out first. The step of arranging the insulating layer and the heat radiating member is preferably performed after mounting the heating element on the circuit.

<Circuit board manufacturing method B>
The circuit board manufacturing method (1) of the present disclosure includes the following steps (1) to (4). However, step (2) is performed before step (3) and step (4), and step (1) is performed before step (3).
(1) Step of installing the case on the heating element mounting surface of the circuit sheet (2) Step of mounting the heating element on the circuit of the circuit sheet (3) Surrounded by the case on the heating element mounting surface of the circuit sheet Step of forming a sealing part in the portion (4) Step of arranging an insulating layer and a heat radiating member on the surface opposite to the heating element mounting surface of the circuit sheet.

In the above method, if step (2) is performed before steps (3) and (4) and step (1) is performed before step (3), the order of each step is not particularly limited. .. For example, either step (1) or step (2) may be performed first, or any of steps (3) and (4) may be performed first, and the steps (1) and (4) may be performed first. Either may be done first.

Details and preferred embodiments of the circuit sheet, case, circuit sheet with case, sealing portion, insulating layer and heat radiating member used in the above methods (manufacturing method A and manufacturing method B) are as described above. Further, the above method may be a method for manufacturing the circuit board of the present disclosure described above.

In the above method, the method of forming the sealing portion in the portion surrounded by the case is not particularly limited. For example, a material for forming a sealing material (sealing material) can be supplied to a portion surrounded by a case and heated or the like as necessary to form the sealing material.

In one embodiment, the sealing portion is formed by a method including a step of supplying a sealing material to a portion surrounded by a case without pressure. Hereinafter, such a method is also referred to as a "non-pressure molding method".

In the non-pressure molding method, the sealing portion can be formed with simple equipment as compared with the method involving pressure such as the transfer molding method. In addition, the formation of voids in the sealing portion can be suppressed more effectively, which is excellent in terms of reliability.

In the present disclosure, if the encapsulant is supplied to the portion surrounded by the case without pressurization, the non-pressurization molding method also includes the case where the encapsulant is pressurized after the encapsulant is supplied. It shall be.

When the sealing portion is formed by a non-pressure molding method, it is preferable that the sealing material supplied to the portion surrounded by the case has fluidity. For example, it may be a fluid solid (particles or the like) or a liquid.

When the encapsulant supplied to the portion surrounded by the case is in the form of particles, the supplied particles are melted to reduce the voids between the particles from the viewpoint of suppressing the formation of voids in the encapsulating portion. Is preferable.

From the viewpoint of further suppressing the formation of voids in the sealing portion, it is possible to carry out a step (decompression step) of supplying the sealing material to the portion surrounded by the case and then depressurizing the portion surrounded by the case. preferable.

By supplying the encapsulant to the portion enclosed by the case and then depressurizing the portion enclosed by the case, for example, when the supplied encapsulant is in the form of particles, the air existing between the particles can be removed. It is possible to suppress the formation of air bubbles remaining inside the molten encapsulant.

From the viewpoint of further suppressing the formation of voids in the sealing portion, it is preferable to carry out the step of bringing the portion surrounded by the case closer to atmospheric pressure (pressurizing step) after performing the depressurizing step in the above method.

By carrying out the pressurizing step after the depressurizing step, the bubbles that could not be suppressed in the depressurizing step are crushed by the pressure, and the formation of voids in the sealing portion can be further suppressed. The method of carrying out the boosting step is not particularly limited. For example, a method may be used in which the opening of the mold whose inside is decompressed is opened to bring the pressure to atmospheric pressure.

When the sealing portion is formed by a non-pressure molding method, the depressurization step is preferably performed before the step of melting the insulating material supplied to the inside of the mold (melting step), and the pressurizing step is a melting step. It is preferable to do it later.

The method of arranging the insulating layer and the heat radiating member on the surface opposite to the heating element mounting surface of the circuit sheet with a case is not particularly limited. For example, it can be carried out using an adhesive or a screw.
Further, for example, a laminated body in which an insulating layer is arranged on a heat radiating member may be produced, and the insulating layer side of the laminated body may be arranged on the side opposite to the heating element mounting surface of the circuit sheet with a case. After arranging the insulating layer on the side opposite to the heating element mounting surface of the circuit sheet with the case, the heat radiating member may be arranged on the insulating layer.

<Manufacturing method 1 of the circuit board of the seventh embodiment>
The circuit board manufacturing method 1 of the seventh embodiment has a circuit, an insulating layer, and a base having an area larger than the element mounting surface of the circuit and having a surface on which the circuit is arranged via the insulating layer. A method for manufacturing a circuit board for manufacturing a circuit board having a substrate in this order, wherein a laminate in which the circuit, the insulating layer, and the base substrate are arranged in this order is prepared, and the circuit and the insulating layer are provided. It has a step of pressurizing the laminated body in a state where a spacer member having substantially the same thickness as the total thickness is arranged on the base substrate so as to be in contact with at least a part of the periphery of the side surface of the circuit and the insulating layer.

In the conventional method of manufacturing a circuit board, since the laminated body is pressurized without arranging the spacer member as described above, it is not possible to pressurize the element mounting surface of the circuit with high uniformity. In the conventional circuit board manufacturing method, for example, the pressure at the time of pressurization varies between the vicinity of the center of the element mounting surface and the peripheral end portion of the element mounting surface, and the pressure is applied to the peripheral end portion of the element mounting surface. Concentration may cause warpage of the manufactured circuit board or peeling of the interface due to the warp.

On the other hand, in the circuit board manufacturing method 1, a spacer member having substantially the same thickness as the total thickness of the circuit and the insulating layer is arranged on the base substrate so as to be in contact with at least a part around the side surface of the circuit and the insulating layer. Pressurize the laminate with. As a result, the spacer member is also pressurized together with the laminated body, and the area of the pressurized surface is increased, so that the pressure is suppressed from being concentrated on the peripheral end portion of the element mounting surface, and the element mounting surface. The whole can be pressurized with high uniformity. Therefore, in the circuit board manufactured by the circuit board manufacturing method 1, the occurrence of warpage is suppressed, and the peeling of the interface due to the warp is suppressed.

Further, in the circuit board manufacturing method 1, the warp of the base board itself can be suitably suppressed by arranging the spacer member on the base board.

Further, by arranging the spacer member on the base substrate so as to be in contact with at least a part of the side surface of the circuit and the insulating layer, the amount of flow of the insulating material in the insulating layer can be adjusted, and the manufactured circuit board is predetermined. It is easy to form an insulating layer having the thickness of.

(Spacer member)
The material of the spacer member used in the method for manufacturing the circuit board of the present disclosure is not particularly limited, and a material having heat resistance to the heating temperature when the laminate is heated as needed in the pressurizing step is preferable. .. Examples of the material of the spacer member include fluorine-based rubber, fluorine-based resin such as polytetrafluoroethylene, copper, iron, alloys containing these metals as main components, stainless steel, and metals such as laminates made of these.

In the circuit board manufacturing method 1, the thickness of the spacer member is not particularly limited as long as it is substantially the same as the total thickness of the circuit and the insulating layer. From the viewpoint of suitably pressurizing the element mounting surface of the circuit, the thickness of the spacer member is preferably equal to or less than the above-mentioned total thickness, and from the viewpoint of pressurizing the element mounting surface of the circuit with higher uniformity, the thickness of the spacer member. The difference between the thickness and the above-mentioned total thickness is preferably 0 μm to 250 μm, more preferably 10 μm to 250 μm, and even more preferably 50 μm to 220 μm.

The ratio of the thickness of the spacer member to the total thickness of the circuit and the insulating layer (thickness of the spacer member / total thickness of the circuit and the insulating layer) is preferably 0.75 to 1.0, preferably 0.875 to 0.875. It is more preferably 0.995.

In the pressurizing step, the spacer member is provided on the side surface of the circuit and the insulating layer from the viewpoint of suppressing the pressure variation at the peripheral end portion of the element mounting surface and suppressing the inter-layer deviation of the circuit and the insulating layer. It is preferably arranged so as to be in contact with at least two peripheral regions and to sandwich the circuit and the insulating layer, and more preferably to be arranged so as to be in contact with the above-mentioned surroundings.
In the present disclosure, "contacting" means that the circuit, the insulating layer, and the spacer member are arranged at positions where at least a part of the side surface of the circuit and the insulating layer can be in contact with the spacer member, and there is no practical problem of inter-layer deviation. It means that it can be aligned to suppress at the level.
Further, a clearance may be provided between the spacer member and the circuit and the insulating layer to facilitate alignment. Good alignment can be achieved by setting the clearance amount at this time to be within an allowable amount of interlaminar deviation.

For example, when the shape of the element mounting surface of the circuit is a square shape such as a square shape or a rectangular shape, the spacer member is arranged so as to be in contact with two opposing surfaces of the side surfaces of the circuit and the insulating layer on the base substrate. It is more preferable that the circuit is arranged so as to be in contact with the four sides of the circuit and the insulating layer on the base substrate.

It is preferable that the circuit board manufacturing method 1 further includes a step of aligning the circuit and the insulating layer on the base board using a spacer member before pressurizing the laminate. For example, a spacer member arranged so as to be in contact with at least two regions around the side surface of the circuit and the insulating layer and sandwiching the circuit and the insulating layer, preferably a spacer member arranged so as to be in contact with the periphery of the circuit and the insulating layer, and a base. The circuit and the insulating layer on the base substrate may be aligned by aligning with the substrate.

The step of pressurizing is preferably performed in a state where a cushion material that can be deformed by pressurization is arranged on the element mounting surface of the circuit. By arranging the cushion material on the element mounting surface of the circuit, the pressure applied to the element mounting surface is dispersed, and the circuit, the insulating layer, and the base substrate tend to be sufficiently adhered to each other. The step of pressurizing may be performed in a state where the cushion material is also arranged on the base substrate side of the laminated body. Further, by using the spacer member in the pressurizing step, it is possible to suppress the deformation of the cushioning material at the time of pressurizing the laminated body, and the number of times the cushioning material is used in manufacturing the circuit board tends to be increased. It is in.

In the pressurizing step, the method of pressurizing the laminate is not particularly limited. The pressurizing pressure is not particularly limited and can be selected from, for example, the range of 0.1 MPa to 30 MPa. More preferably 0.5 MPa from the viewpoint of reducing the springback of the circuit (the peeling of the interface due to the force that causes the circuit to return to the initial flat shape when the pressure is released) and from the viewpoint of ensuring the adhesiveness. It is ~ 15 MPa, more preferably 0.8 MPa ~ 15 MPa. From the viewpoint of enhancing the adhesion between the circuit and the insulating layer, it is preferable to heat and pressurize the laminate. When the laminate is heated and pressurized, the heating temperature of the laminate is not particularly limited and can be selected from, for example, the range of 50 ° C to 290 ° C. From the viewpoint of ensuring adhesiveness and reducing heat damage to the laminate, cushion material, spacer member, etc., the temperature is more preferably 80 ° C. to 250 ° C. The heating time is not particularly limited as long as it is the time required to ensure the adhesiveness, and is preferably 30 seconds to 5 hours. Adhesion may be performed in a short time, and then heat treatment may be performed to cure the adhesive layer in a non-pressurized state. The temperature at this time may be selected from the range of the heating temperature at the time of crimping described above. The device used for pressurizing is not particularly limited, and a flat plate laminator, a vacuum flat plate laminator, a quick press, a flat plate press, a vacuum flat plate press, or the like can be used.

Hereinafter, specific configurations of the circuit, the insulating layer, and the base substrate used in the circuit board manufacturing method of the present disclosure will be described.

(circuit)
The material of the circuit used in the method for manufacturing the circuit board of the present disclosure is not particularly limited as long as it is a conductor, and examples thereof include metal. Examples of the metal include copper, silver, chromium copper, tungsten copper, nickel, nickel-plated copper, aluminum, and aluminum whose surface is modified to alumite. From the viewpoint of conductivity, the metal preferably contains copper.

The thickness of the circuit is not particularly limited and can be selected according to the application of the circuit board and the like. From the viewpoint of increasing the current of the circuit, the thickness of the circuit is preferably 350 μm or more, more preferably 400 μm or more, further preferably 500 μm or more, and 1000 μm or more from the viewpoint of heat dissipation. Is particularly preferred. From the viewpoint of small size and low profile, the thickness of the circuit may be 5000 μm or less. When the thickness of the circuit is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.
When a part of the circuit is embedded in an adjacent member such as an insulating layer, the thickness of the embedded part is also included in the thickness of the circuit.

The circuit has a circuit unit and a space other than the circuit unit, and an insulating portion may be provided in at least a part of the space. When the circuit has a circuit portion and a space, the element mounting surface can be pressurized with higher uniformity by filling the space with an insulating portion. Further, in the circuit before being arranged on the insulating layer and the base substrate, the element mounting surface and the surface opposite to the element mounting surface may be exposed. Even when the circuit has a vertically symmetrical structure in which the front and back surfaces are exposed, the warp of the manufactured circuit board can be suitably suppressed.

The circuit having the above-mentioned space can be obtained, for example, by processing a metal plate into a circuit state having a desired shape. The processing method is not particularly limited, and can be performed by a known method such as punching, cutting, or etching. From the viewpoint of improving the accuracy in circuit fabrication, it is preferable to form the circuit by etching.

When the circuit has a circuit portion and a space other than the circuit portion, the insulating materials used for forming the insulating portion include epoxy resin, phenol resin, urea resin, melamine resin, urethane resin, silicone resin, and unsaturated polyester resin. , Materials containing resins such as acrylic resins. The resin contained in the insulating material may be one kind or two or more kinds. The insulating material may contain components other than the resin, such as an inorganic filler, if necessary.

The thickness of the above-mentioned insulating portion is not particularly limited and can be selected according to the application of the circuit board and the like. The thickness of the insulating portion (thickness of the insulating portion / thickness of the circuit) with respect to the thickness of the circuit is preferably 0.5 or more, more preferably 0.7 or more, and 0, from the viewpoint of ensuring sufficient insulation. 0.9 or more is more preferable. Further, the thickness of the insulating portion / the thickness of the circuit is preferably 1.0 or less, more preferably 0.99 or less, from the viewpoint of workability of element mounting.
When the thickness of the insulating portion is not constant, the arithmetic mean value of the measured values obtained at five arbitrarily selected points may be used as the above value.

(Insulation layer)
The insulating layer in the method for manufacturing a circuit board of the present disclosure is a member located between a circuit and a base board in the circuit board. The preferred form of the insulating material used for forming the insulating layer may be the same as the preferred form of the insulating material used for forming the insulating portion.

The thickness of the insulating layer is not particularly limited and can be selected according to the application of the circuit board. From the viewpoint of ensuring sufficient insulating properties, the thickness of the insulating layer is preferably 30 m or more, more preferably 80 μm or more, and further preferably 120 μm or more from the viewpoint of imparting thermal shock resistance. ..

From the viewpoint of ensuring sufficient heat dissipation, the thickness of the insulating layer is preferably 500 μm or less, more preferably 260 μm or less, and further preferably 220 μm or less.

(Base board)
The base substrate used in the method for manufacturing the circuit board of the present disclosure may be any member as long as the circuit and the insulating layer can be arranged on the base substrate, and may be, for example, a heat dissipation member. The material of the base substrate is not particularly limited, and examples thereof include copper, aluminum, tungsten copper, copper alloys such as molybdenum copper, and nickel-plated copper. The type of the heat radiating member is not particularly limited, and may be a member having a heat radiating function such as a heat spreader or a heat sink, a case having an air or water flow path, a metal foil, a filler resin composite, or the like. The surface of the heat radiating member may be smooth, and may be roughened to improve the adhesiveness with the insulating layer.

<Manufacturing method 2 of the circuit board of the seventh embodiment>
The circuit board manufacturing method 2 of the seventh embodiment is a method of manufacturing a circuit board that manufactures a circuit board having a circuit, an insulating layer, and a base board in this order, wherein the circuit, the insulating layer, and the base board are manufactured. A laminate in which the base substrate is arranged in this order is prepared, and a spacer member having a thickness substantially equal to the total thickness of the circuit, the insulating layer, and the base substrate is formed with at least a part of the periphery of the side surface of the laminate. It has a step of pressurizing the laminated body in a state of being arranged on the same plane as the laminated body so as to be in contact with each other. The description of the preferred form of the circuit board manufacturing method 2 and the matters common to the preferred form of the circuit board manufacturing method 1 described above will be omitted.

In the circuit board manufacturing method 2, spacer members having substantially the same thickness as the total thickness of the circuit, the insulating layer, and the base substrate are arranged on the same plane as the laminated body so as to be in contact with at least a part around the side surface of the laminated body. Pressurize the laminate in this state. As a result, the spacer member is also pressurized together with the laminated body, and the area of the pressurized surface is increased, so that the peripheral end portion of the element mounting surface and the peripheral surface of the surface opposite to the circuit side of the base substrate are applied. The concentration of pressure on the end portion is suppressed, and the entire element mounting surface and the entire surface of the base substrate opposite to the circuit side can be pressurized with high uniformity. Therefore, in the circuit board manufactured by the circuit board manufacturing method 2 of the present disclosure, the occurrence of warpage is suppressed, and the peeling of the interface due to the warp is suppressed.

In the circuit board manufacturing method 2, the thickness of the spacer member is not particularly limited as long as it is substantially the same as the total thickness of the circuit, the insulating layer, and the base board. From the viewpoint of suitably pressurizing the element mounting surface of the circuit, the thickness of the spacer member is preferably equal to or less than the above-mentioned total thickness, and from the viewpoint of pressurizing the element mounting surface of the circuit with higher uniformity, the thickness of the spacer member. The difference between the thickness and the above-mentioned total thickness is preferably 0 μm to 250 μm, more preferably 10 μm to 250 μm, and even more preferably 50 μm to 220 μm.

The ratio of the thickness of the spacer member to the total thickness of the circuit, the insulating layer and the base substrate (thickness of the spacer member / the total thickness of the circuit, the insulating layer and the base substrate) shall be 0.75 to 1.0. It is preferably 0.875 to 0.999, and more preferably 0.875 to 0.999.

In the pressurizing step, the spacer member is provided around the side surface of the laminated body from the viewpoint of suppressing the pressure variation during pressurization at the peripheral end portion of the element mounting surface and from the viewpoint of suppressing the inter-layer deviation of the circuit and the insulating layer. It is preferably arranged so as to be in contact with at least two regions and sandwich the laminated body, and more preferably to be arranged so as to be in contact with the above-mentioned surroundings.

Hereinafter, an example of a conventional circuit board manufacturing method, a circuit board manufacturing method 1, and a circuit board manufacturing method 2 will be described with reference to FIGS. 7A to 7C. 7A to 7C are cross-sectional views of each member in the thickness direction of the laminate 200 or 11 when the laminate 200 or 11 is pressurized by the pressurizing means 105 as shown by an arrow.

FIG. 7A is a schematic configuration diagram showing a conventional method for manufacturing a circuit board. As shown in FIG. 7A, the laminate 200 including the circuit 101, the insulating layer 102, and the base substrate 103 in this order is pressurized without arranging the spacer members. Further, in a state where the cushion material 106 facing the element mounting surface side of the circuit and the base substrate side of the laminate is arranged, the pressurization of the laminate 200 by the pressurizing means 105 is performed via the cushion material 106 as shown by an arrow. Is done. At this time, the laminate 200 may be pressurized and heated.

In the conventional method for manufacturing a circuit board as shown in FIG. 7A, when the laminate 200 is pressurized, the pressure is concentrated on the peripheral end portion of the element mounting surface, so that the manufactured circuit board is warped or warped. The resulting interface peeling may occur or springback may occur.

FIG. 7B is a schematic configuration diagram showing an example of the circuit board manufacturing method 1. As shown in FIG. 7B, in the circuit board manufacturing method 1, the spacer member 107 having substantially the same thickness as the total thickness of the circuit 101 and the insulating layer 102 is in contact with the periphery of the side surface of the circuit 101 and the insulating layer 102. The laminate 210 including the circuit 101, the insulating layer 102, and the base substrate 104 in this order is pressed while being arranged on the base substrate 104.

As shown in FIG. 7B, in an example of the circuit board manufacturing method 1, the spacer member 107 is also pressurized together with the laminated body 210, and the area of the pressurized surface is increased, so that the circumference of the element mounting surface is increased. Since the concentration of pressure on the end portion is suppressed, the occurrence of warpage is suppressed in the circuit board manufactured by the circuit board manufacturing method 1, and the peeling of the interface, springback, etc. due to the warp are suppressed. NS.

FIG. 7C is a schematic configuration diagram showing an example of the circuit board manufacturing method 2. As shown in FIG. 7C, in the circuit board manufacturing method 2, the spacer member 108 having substantially the same thickness as the total thickness of the circuit 101, the insulating layer 102, and the base substrate 103 is brought into contact with the periphery of the side surface of the laminated body 200. The laminated body 200 is pressurized while being arranged on the same plane as the laminated body 200.

As shown in FIG. 7C, in an example of the circuit board manufacturing method 2, the spacer member 108 is also pressurized together with the laminated body 200, and the area of the pressurized surface is increased, so that the circumference of the element mounting surface is increased. Since pressure is suppressed from being concentrated on the end portion and the peripheral end portion of the surface of the base board opposite to the circuit side, the occurrence of warpage is suppressed in the circuit board manufactured by the circuit board manufacturing method 2. Therefore, peeling of the interface, springback, etc. due to warpage are suppressed.

<Circuit board>
In the circuit board of the eighth embodiment of the present disclosure, a circuit, an insulating layer, and a heat radiating member are laminated in this order, the average thickness of the circuit is 500 μm or more, and the average thickness of the insulating layer is 120 μm or more. Is what.
The circuit board of the present disclosure is excellent in power cycle test. The reason is not clear, but when the circuit, the insulating layer and the heat radiating member are laminated in this order, the average thickness of the circuit is set to 500 μm or more, and the average thickness of the insulating layer is set to 120 μm or more. Even if local heat is generated in the circuit, the peeling between the circuit and the insulating layer tends to be suppressed. As a result, it is presumed that the circuit board of the present disclosure will be excellent in the power cycle test.

Hereinafter, the circuit board of the present disclosure will be described with reference to the drawings. The circuit board of the present disclosure is not limited to the following embodiments. Further, the size of the members in the drawings is conceptual, and the relative relationship between the sizes of the members is not limited to the following embodiment.

FIG. 8A is a cross-sectional view of the circuit board 220, which is an embodiment of the circuit board of the present disclosure.
As shown in FIG. 8A, in the circuit board 220, the circuit 112, the insulating layer 113, and the heat radiating member 115 are laminated in this order.
The cross section of the circuit 112 has a trapezoidal shape in which the side of the circuit 112 in contact with the insulating layer 113 is short and the side of the circuit 112 opposite to the side in contact with the insulating layer 113 is long.

In the present disclosure, the average thickness of the circuit 112 is set to 500 μm or more from the viewpoint of promoting heat diffusion using the circuit, and is preferably 1000 μm or more in order to further improve the characteristics for the power cycle test, and is preferably 1500 μm or more. It is more preferable that it is 2000 μm or more, and it is further preferable that it is 2000 μm or more. On the other hand, from the viewpoint of miniaturization and low profile, and from the viewpoint of effectively transmitting the heat generated by the heating element, element, etc. on the circuit surface to the insulating layer side and expanding the heat diffusion area, the average thickness of the circuit 112 The heat is preferably 5000 μm or less, and more preferably 3000 μm or less.
The thickness of the circuit 112 means the thickness of the circuit 112 itself, and when a part of the circuit 112 is embedded in the insulating layer 113, the thickness of the embedded portion is also included in the thickness of the circuit 112.

The width and length of the circuit 112 are not particularly limited and may be selected according to the application of the circuit board and the like. For example, the width and length of the circuit 112 may be 350 μm to 70,000 μm, respectively. When the width or length differs depending on the location of the circuit 112, the arithmetic mean value of the measured values obtained at the five arbitrarily selected locations may be used as the above value.

The surface roughness of the circuit 112 facing the insulating layer 113 should be 0.5 μm or more in order to increase the adhesive strength between the circuit 112 and the insulating layer 113 and improve the characteristics of the circuit board for further power cycle tests. It is preferably 0.6 μm or more, and more preferably 0.7 μm or more. From the viewpoint of insulation, the surface roughness of the circuit 112 on the side facing the insulating layer 113 may be 5.0 μm or less.

From the viewpoint of element mounting, wire bonding, etc., the surface roughness of the circuit 112 on the side opposite to the side facing the insulating layer 113 is preferably less than 0.2 μm, more preferably 0.18 μm or less. It is more preferably 0.15 μm or less. The lower limit of the surface roughness on the side of the circuit 112 facing the insulating layer 113 is not particularly limited.

In the present disclosure, the surface roughness refers to the arithmetic mean roughness Ra. The average roughness Ra is a value obtained based on JIS B 0601: 2013. Specifically, it is a value measured using a 3D microscope (for example, VR-3200 manufactured by KEYENCE, magnification 12 times).
The surface roughness of the circuit 112 facing the insulating layer 113 may be a value measured before the circuit 112 comes into contact with the insulating layer 113 or a precursor of the insulating layer 113 such as a resin composition. Alternatively, it may be a value measured for the circuit 112 obtained by removing the insulating layer 113 and the heat radiating member 115 from the circuit board 220.

The material of the circuit 112 is not particularly limited, and examples thereof include copper, silver, chromium copper, tungsten copper, nickel, nickel-plated copper, aluminum, and aluminum whose surface is modified to alumite.

In order to set the surface roughness of the circuit 112 to a predetermined value, the surface of the circuit 112 may be roughened.
The method for roughening the surface of the circuit 112 is not particularly limited, and the surface may be roughened by a physical method or a chemical method. For example, when the material of the circuit 112 is copper, physical methods include sanding, sandblasting, laser irradiation, and milling. Examples of the chemical method include a MacDermid treatment, a CZ treatment, a blackening treatment, an etching treatment, a plating treatment and the like. The roughening treatment may be carried out by any one method or a combination of two or more. When two or more kinds are combined, the physical method and the chemical method may be combined, the chemical methods may be combined, or the physical methods may be combined.

From the viewpoint of suppressing peeling between the circuit and the insulating layer when stacking the circuits and the adhesion between the insulating material filled between the circuits and the circuit, the circuit 112 has a surface area on the side of the circuit 112 facing the insulating layer 113. It is preferable that the surface surface of the circuit 112 facing the insulating layer 113 is larger than that of the circuit 112 facing the insulating layer 113, and the surface surface of the circuit 112 facing the insulating layer 113 facing the insulating layer 113 of the circuit 112. The ratio to the surface area on the side is preferably 1.001 to 10.0, more preferably 1.01 to 5.0, and even more preferably 1.02 to 4.0.
The surface area of the circuit 112 facing the insulating layer 113 and the surface area of the circuit 112 facing the insulating layer 113 serve as a precursor of the insulating layer 113 or the insulating layer 113 such as a resin composition. For the circuit 112 before contact with the circuit 112, or the circuit 112 obtained by removing the insulating layer 113 and the heat radiating member 115 from the circuit board 220, the shape of each circuit surface is quantified using a length measuring device to obtain the surface area. It can be measured by the conversion method.

The insulating layer 113 contains a resin. The resin contained in the insulating layer 113 is not particularly limited, and examples thereof include curable resins such as epoxy resin, phenol resin, urea resin, melamine resin, urethane resin, silicone resin, unsaturated polyester resin, acrylic resin, and amideimide resin. The resin contained in the insulating layer 113 may be one type or two or more types. From the viewpoint of electrical insulation and adhesiveness to the circuit 112 or the heat radiating member 115, the insulating layer 113 preferably contains at least one selected from the group consisting of epoxy resin, silicone resin, and urethane resin. From the viewpoint of moisture resistance, the insulating layer 113 preferably contains at least one selected from the group consisting of epoxy resin, acrylic resin, and amidimide resin.

From the viewpoint of the balance of various properties required for the insulating layer 113, the epoxy resin is preferable among the above resins. The epoxy resin may be combined with a curing agent. As the curing agent, a phenol curing agent such as phenol novolac resin is preferable.

An epoxy resin having a mesogen structure may be used as the epoxy resin. The mesogen structure includes, for example, a biphenyl structure, a phenylbenzoate structure, a cyclohexylbenzoate structure, an azobenzene structure, a stilbene structure, a terphenyl structure, an anthracene structure, derivatives thereof, and two or more of these mesogen structures via a linking group. Examples include combined structures.

The epoxy resin having a mesogen structure may contain an epoxy compound having one or more structures represented by the following general formula (I).

In the general formula (I), R ¹ to R ⁴ independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹ to R ⁴ are each independently preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. Further, ^{it is preferable that 2 to 4} ^{of R 1} to R 4 are hydrogen atoms, more preferably 3 or 4 are hydrogen atoms, and further, all 4 are hydrogen atoms. preferable. When ^{any one of} R 1 to R ⁴ is an alkyl group having 1 to 3 carbon atoms, it is preferable that at least one of ^{R 1} and R ^{4 is an alkyl group having 1 to 3 carbon atoms.}

Examples of the epoxy compound having the structure represented by the general formula (I) include the epoxy compound represented by the following general formula (M).

Specific examples of ^R 1 ~ ^{R 4} in the general formula (M) is the same as the specific examples of ^R 1 ~ ^{R 4} in formula (I), is the same preferred ranges thereof.

The insulating layer 113 may contain a component other than the resin such as a filler, if necessary.
Examples of the filler include a non-conductive filler and a conductive filler.
Examples of the non-conductive filler include aluminum oxide (alumina), magnesium oxide, aluminum nitride, boron nitride, silicon nitride, silica (silicon oxide), aluminum hydroxide, barium sulfate and the like.
Examples of the conductive filler include gold, silver, nickel, copper and the like. Among them, from the viewpoint of thermal conductivity, the filler is preferably at least one selected from the group consisting of aluminum oxide (alumina), boron nitride, magnesium oxide, aluminum nitride and silica (silicon oxide), and boron nitride. It is more preferable that it is at least one selected from the group consisting of aluminum oxide (alumina) and aluminum oxide (alumina). As the filler, one type may be used alone or two or more types may be used in combination. In addition, "using two or more kinds of fillers together" means, for example, when two or more kinds of fillers having the same component but different average particle diameters are used, when two or more kinds of fillers having the same average particle size but different components are used, and when the average. There are cases where two or more types of fillers having different particle sizes and types are used.

The shape of the filler is not particularly limited, and examples thereof include powder, spherical, and fibrous.

Other components that may be contained in the insulating layer 113 include a curing accelerator, a silane coupling agent, a stress relaxant, a colorant, a flame retardant, an antifoaming agent, and the like. As for each component which may be contained in the insulating layer 113, one type may be used alone or two or more types may be used in combination.

The average thickness of the insulating layer 113 is 120 μm or more, preferably more than 200 μm, more preferably 210 μm or more, and further preferably 230 μm or more. On the other hand, from the viewpoint of ensuring sufficient heat dissipation, the average thickness of the insulating layer 113 is preferably 500 μm or less, and more preferably 310 μm or less.

The thermal conductivity of the insulating layer 113 is preferably 6 W / (m · K) or more, more preferably 8 W / (m · K) or more, and preferably 10 W / (m · K) or more. More preferred. The upper limit of the thermal conductivity is not particularly limited, and may be, for example, 50 W / (m · K) or less.
The thermal conductivity of the insulating layer 113 is measured as follows. The thermal diffusivity of the insulating layer 113 is evaluated by the xenon flash method (for example, trade name: LFA447 nanoflash of NETZSCH). The thermal conductivity of the insulating layer 113 is calculated from the product of this value, the density measured by the Archimedes method, and the specific heat measured by DSC (differential scanning calorimetry device; for example, a trade name of PerkinElmer: DSC Pyris1). Ask.

The glass transition temperature (Tg) of the insulating layer 113 is preferably 170 ° C. or higher, more preferably 180 ° C. or higher, and further preferably 250 ° C. or higher in order to further improve the characteristics for the power cycle test. preferable. The Tg of the insulating layer 113 is not even limited.
The glass transition temperature of the insulating layer 113 refers to a value measured using a differential scanning calorimetry device (DSC). For example, a part of the insulating layer 113 is weighed in an aluminum pan, and a differential scanning calorimeter (DSC) (“DSC8500”, PerkinElmer) is used to set the temperature at which the baseline changes (secondary transition) to the glass transition temperature. May be regarded as.

The type of the heat radiating member 115 is not particularly limited, and examples thereof include a metal plate and a metal foil. The heat radiating member 115 may be a member exhibiting a heat radiating function such as a heat spreader.
The material of the heat radiating member 115 is not particularly limited, and examples thereof include copper, aluminum, tungsten copper, copper alloys such as molybdenum copper, and nickel-plated copper.

The average thickness of the heat radiating member 115 is preferably 100 μm or more from the viewpoint of improving heat radiating property, more preferably 1000 μm or more from the viewpoint of obtaining effective heat radiating property, and the heat capacity of the heat radiating member and the thickness of the circuit. It is more preferably 1800 μm or more from the viewpoint of obtaining high heat dissipation utilizing efficient heat diffusion utilizing the heat. On the other hand, from the viewpoint of small size and low profile, the average thickness of the heat radiating member 115 is preferably 10 cm or less, and more preferably 5000 μm or less.

In order to increase the adhesive strength between the heat radiating member 115 and the insulating layer 113 and improve the characteristics of the circuit board for further power cycle tests, the surface roughness of the heat radiating member 115 facing the insulating layer 113 is 0 in Ra. It is preferably 5.5 μm or more, more preferably 0.6 μm or more, and further preferably 0.8 μm or more. From the viewpoint of insulation, the surface roughness of the heat radiating member 115 on the side facing the insulating layer 113 may be 5.0 μm or less.

From the viewpoint of element mounting, wire bonding, etc., the surface roughness of the heat radiating member 115 on the side opposite to the side facing the insulating layer 113 is preferably less than 0.2 μm in Ra, and preferably 0.18 μm or less. More preferably, it is 0.15 μm or less. The lower limit of the surface roughness of the heat radiating member 115 on the side opposite to the side facing the insulating layer 113 is not particularly limited.
The surface roughness of the heat radiating member 115 facing the insulating layer 113 and the surface roughness of the heat radiating member 115 facing the insulating layer 113 are the surfaces of the circuit 112 facing the insulating layer 113. The roughness and the surface roughness on the side opposite to the side facing the insulating layer 113 of the circuit 112 can be measured in the same manner.

From the viewpoint of heat dissipation as a circuit board, the total average thickness of the circuit 112 and the heat dissipation member 115 is preferably 600 μm or more, and heat dissipation using the thickness of the circuit and heat dissipation using the heat capacity of the heat dissipation member are used. From the viewpoint of obtaining properties, it is more preferably 1200 μm or more, and further preferably 4000 μm or more from the viewpoint of obtaining more efficient heat dissipation. On the other hand, from the viewpoint of miniaturization and reduction in height, the total average thickness of the circuit 112 and the heat radiating member 115 is preferably 10 cm or less, more preferably 10,000 μm or less, and further preferably 6000 μm or less.

From the viewpoint of more efficiently realizing heat dissipation, the ratio of the average thickness of the circuit 112 to the average thickness of the heat dissipation member 115 (circuit / heat dissipation member) is preferably 1.0 to 30, preferably 1.0. It is more preferably ~ 5.0, and even more preferably 1.0 to 3.0.

The coefficient of thermal expansion of the circuit 112 and the coefficient of thermal expansion of the heat radiating member 115 may be the same or different.
The coefficient of thermal expansion of the circuit 112 or the heat radiating member 115 means the coefficient of thermal expansion of the material constituting the circuit 112 or the heat radiating member 115. When the circuit 112 or the heat radiating member 115 is made of copper, the coefficient of thermal expansion of the circuit 112 or the heat radiating member 115 means the coefficient of thermal expansion of copper.
The ratio of the coefficient of thermal expansion of the circuit 112 to the coefficient of thermal expansion of the heat dissipation member 115 (circuit / heat dissipation member) is preferably 0.5 to 2.0, more preferably 0.55 to 1.8. , 0.6 to 1.7, more preferably.

The breaking voltage between the circuit 112 and the heat radiating member 115 is preferably 2.5 kV or more, more preferably 3.0 kV or more, and even more preferably 3.5 kV or more.
The breaking voltage between the circuit 112 and the heat radiating member 115 is a value obtained by applying the breaking voltage between the circuit and the heat radiating member at 100 V / sec and measuring the potential difference when a short circuit occurs.

The partial discharge start voltage between the circuit 112 and the heat radiating member 115 is preferably 2.5 kV or more, more preferably 3.0 kV or more, and even more preferably 3.5 kV or more.
The partial discharge start voltage between the circuit 112 and the heat radiating member 115 refers to a value measured by the method of the measurement standard IEC 60664-1.

The method for manufacturing the circuit board of the eighth embodiment of the present disclosure is not particularly limited, and a conventionally known method can be used.
As a method of using a resin sheet, for example, a resin sheet is arranged between a pair of metal plates, and if necessary, a curing treatment is performed to form the resin sheet as an insulating layer 113, and then a circuit is formed on one of the pair of metal plates by etching or the like. Method of patterning 112; A metal plate arranged on a temporary support is patterned by etching or the like to form a circuit 112, and a resin sheet is arranged between the circuit 112 and a metal plate constituting the heat radiating member 115 to temporarily support the circuit 112. Examples thereof include a method of removing the body and performing a curing treatment as necessary to form the resin sheet as the insulating layer 113.
Further, as a method of using the liquid resin composition, for example, the liquid resin composition is applied to the surface of the metal plate, dried to form a resin composition layer, and then the metal plate is arranged on the resin composition layer. If necessary, a curing treatment is performed to form the resin composition layer as the insulating layer 113, and then the circuit 112 is patterned on one of the pair of metal plates by etching or the like.
Further, as a method using a resin sheet, a circuit 112 formed by a known method such as punching or cutting is arranged on the surface of the resin sheet arranged on the heat radiating member 115, and curing treatment is performed as necessary. A method of using the resin sheet as the insulating layer 113 may be used.

The method of applying the liquid resin composition to the surface of the metal plate is not particularly limited. For example, a dispense method, a spray method, a gravure method, a screen printing method, a screen printing method using a metal mask, a transfer method and the like can be used.

The liquid resin composition may be liquid at least at the time of application to the metal plate. The viscosity of the liquid resin composition is not particularly limited, and for example, the viscosity when applied to a metal plate is preferably 10 Pa · s or less. The viscosity of the liquid resin composition is determined by an E-type viscometer (for example, Toki Sangyo Co., Ltd., TV- It is a value measured at 5 rotations / minute (rpm) using 33).

From the viewpoint of enhancing the adhesion between the metal plate and the resin sheet, it is preferable to perform at least one of heating and pressurization when arranging the resin sheet between the pair of metal plates, and it is more preferable to perform both. The heating temperature is not particularly limited and can be selected from, for example, the range of 50 ° C. to 250 ° C. The pressurizing pressure is not particularly limited and can be selected from, for example, the range of 0.1 MPa to 50 MPa.

<Semiconductor device>
The semiconductor device of the present disclosure includes the circuit board and the semiconductor element of the eighth embodiment of the present disclosure.
Examples of semiconductor elements include elements such as active elements and passive elements. Examples of active elements include semiconductor chips, transistors, diodes, thyristors and the like. Examples of the passive element include a capacitor, a resistor, a coil and the like. It can also be applied to electronic components that are modularized by incorporating a plurality of elements such as these active elements and passive elements.

Since the circuit board and the semiconductor device in this embodiment are suitable for increasing the current and tend to be excellent in insulation reliability and heat dissipation, a power semiconductor package such as an IGBT (Insulated Gate Bipolar Transistor; Insulated Gate Bipolar Transistor) Can be suitably used for the above-mentioned applications.

<Circuit sheet of the eighth embodiment>
The circuit sheet of the eighth embodiment of the present disclosure is provided between a plurality of circuits and the plurality of circuits, and in the circuit, at least a part of an element mounting surface on which an element is mounted and the element mounting surface. The surface of the insulating portion on the side opposite to the element mounting surface has an insulating portion that holds relative positions of the plurality of circuits so that at least a part of the surface on the opposite side is exposed. A circuit sheet that is recessed toward the element mounting surface side of the circuit on the side opposite to the element mounting surface.
Since the surface of the insulating portion on the side opposite to the element mounting surface is recessed toward the element mounting surface rather than the surface opposite to the element mounting surface of the circuit, the insulating layer is on the side opposite to the element mounting surface in the circuit sheet. The gas between the circuit sheet and the insulating part escapes to the outside of the circuit sheet through the recessed portion, so that air bubbles are trapped at the interface between the circuit sheet and the insulating part. Is suppressed. As a result, it is possible to suppress the occurrence of partial discharge on the circuit board, deterioration of insulation resistance, and the like.

The maximum value of the distance between the surface of the insulating portion and the surface opposite to the element mounting surface of the circuit is preferably 20 μm or less, preferably 15 μm or less, from the viewpoint of the adhesiveness between the insulating layer and the insulating portion. Is more preferable.
The maximum value of the above-mentioned distance is preferably 1 μm or more from the viewpoint of preferably suppressing trapping of air bubbles at the interface between the circuit sheet and the insulating portion.
The maximum value of the above-mentioned distance may be adjusted by, for example, removing the surface of the circuit by etching treatment or the like, or removing the surface of the insulating portion preferentially over the surface of the circuit by blasting treatment or the like.

An example of the configuration of the circuit sheet of the present disclosure will be described with reference to the drawings.
As shown in FIG. 9A, the circuit sheet 230 includes a circuit 121 and an insulating portion 122 provided between the circuits 121, and the surface of the insulating portion 122 on the side opposite to the element mounting surface is an element of the circuit 121. It is recessed toward the element mounting surface rather than the surface opposite to the mounting surface.

In the circuit sheet 230, the periphery of the circuit 121 is covered with the insulating portion 122, and the insulating portion 122 is located on the outer periphery of the circuit sheet 230. As a result, the gas between the circuit sheet 230 and the insulating portion 122 preferably escapes to the outside of the circuit sheet 230 through the recessed portion described above, so that air bubbles are generated at the interface between the circuit sheet 230 and the insulating portion 122. Is preferably suppressed from being trapped.

The preferred embodiment of the circuit sheet of the eighth embodiment, the circuit board including the circuit sheet of the eighth embodiment, and the method of manufacturing the circuit board using the circuit sheet of the eighth embodiment are the same as those of the above-described embodiments. Therefore, the description thereof will be omitted.

<Circuit sheet of the ninth embodiment>
The circuit sheet of the ninth embodiment of the present disclosure is provided between a plurality of circuits and the plurality of circuits, and in the circuit, at least a part of the heating element mounting surface and opposite to the heating element mounting surface. It has an insulating portion that holds the relative positions of the plurality of circuits so that at least a part of the side surface is exposed, and the height of the surface of the circuit opposite to the heating element mounting surface. A circuit sheet having a variation of 40 μm or less per 10 mm in the plane direction.
In the circuit sheet of the present disclosure, the height variation of the surface opposite to the heating element mounting surface is 40 μm or less per 10 mm in the plane direction, so that the height of the surface opposite to the heating element mounting surface in the circuit is Variations are suppressed. As a result, the warp of the circuit sheet is also suppressed. For example, when the circuit board and the insulating layer are bonded to each other to manufacture a circuit board, cracks due to the warp of the circuit sheet and peeling of the interface are suppressed. can do.

From the viewpoint of suitably suppressing the occurrence of cracks due to the warp of the circuit sheet, peeling of the interface, etc. in the manufacture of the circuit board, the variation in the height of the surface opposite to the heating element mounting surface in the circuit is It is preferably 30 μm or less, and more preferably 20 μm or less per 10 mm in the plane direction. From the viewpoint of the productivity of the circuit sheet, the above-mentioned height variation is preferably 5 μm or more per 10 mm in the plane direction.

An example of the configuration of the circuit sheet of the present disclosure will be described with reference to the drawings.
As shown in FIG. 10A, the circuit sheet 240 of the present disclosure includes a plurality of circuits 131 and an insulating portion 132 that holds the relative positions of the plurality of circuits 131. Further, in the circuit 131, the height variation of the surface opposite to the heating element mounting surface (that is, the surface on the vertically lower side in FIG. 10A) is 40 μm or less per 10 mm in the plane direction. For example, the variation in height of the surface opposite to the heating element mounting surface satisfies H (μm) / L (mm) ≦ 40 (μm) / 10 (mm) when H μm per L mm in the plane direction.

The preferred embodiment of the circuit sheet of the ninth embodiment, the circuit board including the circuit sheet of the ninth embodiment, and the method of manufacturing the circuit board using the circuit sheet of the ninth embodiment are the same as those of the above-described embodiments. Therefore, the description thereof will be omitted.

<Circuit sheet of the tenth embodiment>
The circuit sheet of the tenth embodiment of the present disclosure is provided between a plurality of circuits and the plurality of circuits, and in the circuit, at least a part of the heating element mounting surface and opposite to the heating element mounting surface. It has an insulating portion that holds the relative positions of the plurality of circuits so that at least a part of the side surface is exposed, and the variation in the height of the heating element mounting surface of the circuit is per 10 mm in the plane direction. It is a circuit sheet having a size of 40 μm or less.
In the circuit sheet of the present disclosure, since the variation in the height of the heating element mounting surface of the circuit is 40 μm or less per 10 mm in the plane direction, the variation in the height of the heating element mounting surface in the circuit is suppressed. This facilitates the arrangement of the heating element, the connection between the heating element and the bonding wire, and the like, and improves the workability of element mounting.

From the viewpoint of preferably suppressing the workability of element mounting, the variation in the height of the heating element mounting surface in the circuit is preferably 30 μm or less, and more preferably 20 μm or less per 10 mm in the plane direction. From the viewpoint of the productivity of the circuit sheet, the above-mentioned height variation is preferably 5 μm or more per 10 mm in the plane direction.

An example of the configuration of the circuit sheet of the present disclosure will be described with reference to the drawings.
As shown in FIG. 11A, the circuit sheet 250 of the present disclosure includes a plurality of circuits 141 and an insulating portion 142 that holds the relative positions of the plurality of circuits 141. Further, in the circuit 141, the variation in height of the heating element mounting surface (that is, the vertically upper surface in FIG. 11A) is 40 μm or less per 10 mm in the plane direction. For example, when the height variation of the heating element mounting surface is H'μm per L'mm in the plane direction, H'(μm) / L'(mm) ≦ 40 (μm) / 10 (mm) is satisfied.

The preferred embodiment of the circuit sheet of the tenth embodiment, the circuit board including the circuit sheet of the tenth embodiment, and the method of manufacturing the circuit board using the circuit sheet of the tenth embodiment are the same as those of the above-described embodiments. Therefore, the description thereof will be omitted.

<Circuit sheet with case of the eleventh embodiment>
The circuit sheet with a case of the eleventh embodiment of the present disclosure includes a plurality of circuits, a holding unit provided on one surface side of the plurality of circuits, and a holding unit for holding the relative positions of the plurality of circuits. It has a case provided on the top and surrounds the plurality of circuits when viewed from one surface side of the circuits, and the other surface of the plurality of circuits is exposed.

A circuit sheet including a plurality of circuits and a holding unit (for example, a holding sheet) for holding relative positions of the plurality of circuits provided on one surface side of the plurality of circuits is easily deformed, and the plurality of circuits There is a problem that the handleability is poor when the is attached to the insulating layer or the like arranged on the heat radiating member. On the other hand, in the circuit sheet with a case of the present disclosure, since a case surrounding a plurality of circuits is arranged on the heating element mounting surface of the circuit sheet, the circuit sheet is not easily deformed and an insulating layer arranged on the heat radiating member. And the circuit sheet with a case can be easily attached, and the handling property is excellent.

Regarding the circuit sheet with a case of the present disclosure, it is preferable that the holding portion can be peeled off from a plurality of circuits. As a result, after the circuit sheet with the case is attached to the insulating layer arranged on the heat radiating member, the holding portion provided on one surface side of the plurality of circuits can be peeled off from the plurality of circuits. , A heating element or the like may be mounted on one surface side of a plurality of circuits, wire bonding or the like may be performed, or the mounted heating element may be sealed with a sealing material.

When the holding portion provided on one surface side of a plurality of circuits is peeled off from the plurality of circuits, the case may be peeled off together with the holding portion, and the holding portion of the portion provided with the case remains on the circuit sheet with the case. The holding portion provided on one surface of the plurality of circuits may be separated from the plurality of circuits.

It is preferable that at least a part of one surface of the plurality of circuits is a heating element mounting surface on which the heating element is mounted. Further, an insulating portion may be provided between the plurality of circuits, and the insulating portion may not be provided.

<Manufacturing method of circuit board of the ninth embodiment>
The method for manufacturing a circuit board according to a ninth embodiment of the present disclosure includes the cased circuit sheet of the eleventh embodiment of the present disclosure and the insulation arranged on the exposed other surface side of the circuit in the cased circuit sheet. It has a step of pressurizing a laminated body in which a layer and a heat radiating member are arranged in this order. The method of pressurizing the above-mentioned laminate is not particularly limited, and can be selected from the methods generally performed in the manufacturing process of the circuit board, and the method described in other embodiments may be appropriately adopted.

In the method for manufacturing a circuit board of the present disclosure, the holding portion can be peeled from a plurality of circuits, and it is preferable to further have a step of peeling the holding portion from one surface of the plurality of circuits after the step of pressurizing. As a result, a heating element or the like can be mounted on one surface side of a plurality of circuits, wire bonding or the like can be performed, and then the mounted heating element or the like can be sealed with a sealing material. Can be done.

Next, the present invention will be specifically described with reference to Examples, but the scope of the present invention is not limited to Examples.

[Example 1A]
(Making a circuit sheet)
The circuit of FIG. 1 was formed by etching a copper plate (model number; C1100 1 / 4H) having a thickness of 2.0 mm with an aqueous solution of cupric chloride. A step with a width of 510 μm was provided around the circuit. A step (width 1.0 mm) was provided for connecting the insulating portion provided inside the circuit and the insulating portion provided outside the rotating portion. The thickness of these steps was 1 mm. Ra on the side surface and the step of the circuit was 2.0 μm, respectively.
A 25 μm polyimide film (elastic modulus; 5 GPa) and an adhesive layer (thickness: 10 μm) are laminated on the element mounting surface of the circuit in which a step is formed, and the circuit sheet with the protective film is attached. bottom.
Next, using a transfer molding machine, transfer molding was performed using an epoxy-based insulating material (Hitachi Kasei Co., Ltd.) under the conditions of a molding pressure of 7 MPa and a curing time of 300 seconds. The thickness of the insulating portion was 1.99 mm.

(evaluation)
When the boundary between the circuit of the obtained circuit sheet and the insulating portion was observed with a microscope of 400 times, it adhered well. Water was used as a substitute for the silicon gel that seals the circuit sheet, and it was evaluated whether or not bubbles were generated from the boundary between the circuit and the insulating part. Specifically, when the circuit was put into water and then the water was heated to 80 ° C., no bubbles were generated from the boundary between the circuit and the insulating portion.

(Manufacturing of circuit board)
The circuit sheet obtained above is dried, a protective film is reattached to one surface of the circuit sheet, and a roughening solution (manufactured by MacDermid Performance Solutions, trade name; Multibond 150) is used to reattach the circuit sheet. The roughening treatment was performed so that Ra on the other surface of the above was 1.0 μm. Then, the protective film was peeled off from the circuit sheet. The Ra of the surface from which the protective film was peeled off was measured and found to be 0.2 μm.
Next, a 2.0 mm thick copper plate (model number; C1100 1 / 4H) was prepared as a heat radiating member, and one surface of the copper plate was subjected to the same roughening treatment as described above. After the roughening treatment, Ra on one surface of the copper plate was 1.0 μm.
The heat-dissipating member, the film for forming the insulating layer (manufactured by Hitachi Kasei Co., Ltd., HT1500), and the circuit sheet from which the protective film has been peeled off are removed in this order so that the surface of the heat-dissipating member that has been roughened is on the side of the film for forming the insulating layer. After laminating, pressure-bonding was performed under the conditions of 180 ° C. for 3 hours and 4 MPa to prepare a circuit board.

(evaluation)
When the produced circuit board was subjected to a reflow test at 290 ° C. for 10 minutes, neither peeling between the circuit and the insulating portion and peeling between the bottom surface of the circuit and the insulating layer were observed. In the manufactured circuit board, the element mounting could be performed well. When the circuit was put into water, which is a substitute for silicon gel, and heated to 80 ° C., no bubbles were generated from the boundary between the circuit and the insulating part.
When a voltage of 1.0 kV was applied between the circuit and the heat radiating member, the insulation resistance was good without breaking the insulation. When a voltage of 1.0 kV was applied between adjacent circuits, the insulation resistance was good without breaking the insulation.

[Example 2A]
In Example 1A, a step with a width of 1000 μm was provided around the circuit. Further, a step (width 510 μm) for connecting the insulating portion provided inside the circuit and the insulating portion provided outside the rotating portion is provided, the thickness of these steps is set to 0.5 mm, and the side surface of the circuit is set. A circuit sheet was produced in the same manner as in Example 1A except that Ra of the step was set to 1.0 μm.

(evaluation)
When the boundary between the circuit of the obtained circuit sheet and the insulating part was observed with a microscope of 400 times, it was found to be well connected. When the circuit was put into water, which is a substitute for silicon gel, and heated to 80 ° C., no bubbles were generated from the boundary between the circuit and the insulating part.

(Manufacturing and evaluation of circuit boards)
Using the prepared circuit sheet, a circuit board was prepared in the same manner as in Example 1A. In the manufactured circuit board, the element mounting could be performed well. When the circuit was put into water, which is a substitute for silicon gel, and heated to 80 ° C., no bubbles were generated from the boundary between the circuit and the insulating part.
When a voltage of 1.0 kV was applied between the circuit and the heat radiating member, the insulation resistance was good without breaking the insulation. When a voltage of 1.0 kV was applied between adjacent circuits, the insulation resistance was good without breaking the insulation.

[Comparative Example 1A]
A circuit sheet was produced in the same manner as in Example 1A except that no step was provided in Example 1A.

(evaluation)
When the boundary between the circuit and the insulating part of the obtained circuit sheet was observed with a microscope of 400 times, peeling occurred at the boundary between the circuit and the insulating part. When the circuit was put into water, which is a substitute for silicon gel, and heated to 80 ° C., bubbles were generated from the boundary between the circuit and the insulating part.

(Manufacturing and evaluation of circuit boards)
Using the prepared circuit sheet, a circuit board was prepared in the same manner as in Example 1A. While the device could be mounted well on the manufactured circuit board, when the circuit was put into water, which is a substitute for silicon gel, and heated to 80 ° C, bubbles were generated from the boundary between the circuit and the insulating part. bottom.
When a voltage of 1.0 kV was applied between adjacent circuits, dielectric breakdown did not occur, but partial discharge occurred at 0.8 kV. When a voltage of 1.0 kV was applied between the circuit and the heat radiating member, dielectric breakdown occurred at 0.7 kV. When the cross section of the circuit board was cut and the cut surface was observed, the insulating part near the boundary between the circuit and the insulating part was damaged.

[Example 1C]
(Circuit fabrication)
A circuit was formed by etching a copper plate (model number; C1100 1 / 4H) having a thickness of 2.0 mm.
A protective film in which a 25 μm polyimide film (elastic modulus; 5 GPa) and an adhesive layer (thickness: 10 μm) were laminated was attached to the element mounting surface of the circuit in the arrangement shown in FIG. 3D, and the circuit was temporarily fixed.

(Making a circuit sheet)
Using a transfer molding machine, transfer molding was performed so as to fill the gaps between circuits with an epoxy-based insulating material (Hitachi Kasei Co., Ltd.) under the conditions of a molding pressure of 7 MPa and a curing time of 300 seconds. Then, the protective film was peeled off to obtain a circuit sheet having a length of 80 mm and a width of 40 mm. When the thicknesses at the four corners and the center were measured using a microgauge, the variation in thickness was ± 5 μm.

(Measurement of warpage amount)
The circuit sheet was placed on a flat surface, and the height at the center and the heights at the four corners were measured using a height gauge. At this time, the circuit sheet is arranged so that the central portion is convex.
The amount of warpage was calculated by the following formula and evaluated according to the following evaluation criteria.
(Amount of warpage) = (Height at the center)-(Average height at the four corners)
[Evaluation criteria]
A: The amount of warpage of the circuit sheet is 50 μm or less, which is good. B: The amount of warpage of the circuit sheet is more than 50 μm, which is defective.

When the amount of warpage of the circuit sheet obtained in Example 1C was measured, the amount of warpage was 30 μm, and the warp evaluation was good.

[Examples 2C to 12C]
A circuit sheet was produced in the same manner as in Example 1C except that the thickness of the copper plate and the pattern shape of the circuit were changed as shown in Table 1. In all the examples, the variation in thickness was within ± 5 μm.
The results of the warp evaluation are shown in Table 1.

[Comparative Example 1C]
In Example 1C, a circuit sheet was produced in the same manner except that the pattern shape was shown in FIG. 3H. The variation in thickness was within ± 5 μm. The amount of warpage of the circuit sheet was 190 μm, and the warp evaluation was poor.

[Comparative Examples 2C-9C]
A circuit sheet was produced in the same manner as in Example 1C except that the thickness of the copper plate and the pattern shape of the circuit were changed as shown in Table 1. In all the comparative examples, the variation in thickness was within ± 5 μm.
The results are shown in Table 1.

The circuit sheet shown in FIGS. 3D to 3G is at least one on a straight line in an arbitrary direction that passes between the two circuits 31 and is parallel to the element mounting surface when viewed from the element mounting surface of the circuit 31. The circuit 31 was located. On the other hand, the circuit sheets shown in FIGS. 3H to 3J pass between the two circuits 31 and are on at least one straight line parallel to the element mounting surface when viewed from the element mounting surface of the circuit 31. Had a configuration that did not exist.
In Examples 1C to 12C, since the circuit sheet has any of the structures shown in FIGS. 3D to 3G, it was possible to suppress the occurrence of warpage of the circuit sheet.

[Example 13C]
A film for forming an insulating layer (Hitachi Kasei Co., Ltd., HT1500) was placed on one surface of a 2.0 mm thick copper plate (model number; C1100 1 / 4H) as a heat radiating member, and temporarily crimped using a laminator. Further, the circuit sheet prepared in Example 1C was placed on the insulating layer and pressure-bonded under the conditions of 180 ° C. for 3 hours and 4 MPa. The circuit board was arranged so that the central portion of the circuit sheet was convex in the direction opposite to the insulating layer.
When the thickness of the circuit board including the heat radiating member was measured by the same method as in Example 1C, the variation was ± 5 μm. When the amount of warpage of the circuit board was measured by the same method as in Example 1C, it was 25 μm, and the warp evaluation was good.

[Examples 14C, 15C]
In Example 13C, a circuit board was produced in the same manner except that the pattern shape, the thickness of the circuit sheet, and the thickness of the heat radiating member were changed as shown in Table 2. In each case, the thickness variation was within ± 5 μm. The amount of warpage of the circuit board was also 50 μm or less, and the warp evaluation was good.

[Example 16C]
In Example 13C, a circuit board was produced by the same method except that the space between the circuits was not filled with an insulating portion. The amount of warpage of the circuit board was 22 μm, and the warp evaluation was good.

[Example 17C]
In Example 16C, a circuit board was produced in the same manner except that the pattern shape, the thickness of the circuit sheet, and the thickness of the heat radiating member were changed as shown in Table 2. The warp of the circuit board was 50 μm or less, and the warp evaluation was good.

[Comparative Examples 10C to 12C]
In Example 13C, a circuit board was produced in the same manner except that the pattern shape, the thickness of the circuit sheet, and the thickness of the heat radiating member were changed as shown in Table 2. In each case, the thickness variation was within ± 5 μm, but the warp of the circuit board was also larger than 50 μm, and the warp evaluation was poor.

[Comparative Examples 13 to 15]
In Comparative Examples 10 to 12, circuit boards were produced in the same manner except that the spaces between the circuits were not filled with insulating portions. The warp of the circuit board was larger than 50 μm, and the warp evaluation was poor. Further, the heat radiating member was also deformed due to the pressure during crimping. In the comparative example in which the insulating portion was provided, no deformation of the heat radiating member was observed.

In Examples 13C to 18C, since the circuit sheet has any of the structures shown in FIGS. 3D to 3F, it was possible to suppress the occurrence of warpage of the circuit board.

<Example 1D>
(Circuit fabrication)
A circuit having a width of 3.0 mm, a length of 10 mm, and a height of 2.0 mm was formed by punching with a press using a copper plate having a thickness of 2.0 mm (model number: C1100 1 / 4H). One surface (element mounting surface) of the circuit was a flat surface intersecting the cut surface of the copper plate at a right angle, and the other surface had a radius of curvature of the corner portion of 0.03 mm.
The adhesive layer side of the protective film in which a polyimide film (flexural modulus; 5 GPa) having a thickness of 25 μm and an adhesive layer (thickness: 10 μm) was laminated was attached to the element mounting surface side of the formed four circuits.

(Making a circuit sheet)
An insulating part was formed by transfer molding between the circuits to which the protective film was attached. Specifically, the circuit is sandwiched between a pair of molds A and B heated to 180 ° C. of the transfer molding machine, and epoxy-based insulation is applied so as to cover between the circuits and around the circuit while keeping the molds parallel. The material (manufactured by Hitachi Kasei Co., Ltd.) was filled with a molding pressure of 7 MPa and cured with a curing time of 300 seconds. Then, the protective film was peeled off to obtain a circuit sheet. The protective film was in the form of a film and could be easily peeled off. The warp of the circuit sheet did not interfere with the pressure lamination.

Measure the maximum values d and d'of the height difference between the insulating part of the circuit sheet and the adjacent circuit with a height measuring device, and measure the width of the part where the circuit and the insulating part overlap in the thickness direction with a plane length measuring machine. bottom. The results are shown in Table 3. Since the width of the overlapping portion on the element mounting surface side could hardly be observed, it is set to <1 μm.

<Examples 2D to 6D>
A circuit sheet was produced in the same manner as in Example 1D except that the circuit processing method, the circuit thickness, the protective film thickness, and the flexural modulus were changed as shown in Table 3. In each of Examples 2D to 6D, the protective film could be easily peeled off. The warp of the circuit sheet did not interfere with the pressure lamination. The circuit was formed by etching by etching the copper plate with ferric chloride from both sides.

<Comparative Example 1D>
A circuit sheet was produced in the same manner as in Example 1D except that the protective films used in Example 1D were not used and the molds A and B were directly contacted with each other on both sides of the circuit to form an insulating layer. As a result, d = 0 μm, d'= 0 μm, and the width of the overlapping portion on the element mounting surface side was 12 μm. Further, when the molds were released from the molds A and B, the circuit sheet was stuck to one side, and it was difficult to release the mold from the mold.

<Example 7D>
(Manufacturing of circuit board)
On the side opposite to the element mounting surface of the circuit sheet produced in Example 1D, an insulating layer of the B stage (thickness 210 μm, Hitachi Kasei Co., Ltd., product name; HT1500) and a copper plate (model number: C1100 1) as a heat dissipation member. / 4H) was arranged in this order to obtain a laminated body. A fluororubber sheet having a thickness of 2.0 mm was applied as a cushioning material to the circuit sheet side of the laminated body, and pressure-laminated to prepare a circuit board. The conditions for pressure laminating were pressure; 4 MPa, temperature: 180 ° C., pressurization time: 3 hours, and the process was carried out in a vacuum state.
In the laminated circuit board, the insulating material hardly protruded from the circuit on the element mounting surface, and the insulating portion had a dent, so that the elements could be easily aligned and mounted well. In addition, there was no peeling between the circuit and the insulating layer, and between the heat radiating member and the insulating layer, and good adhesion was possible.

<Examples 8D to 12D>
A circuit board was produced in the same manner as in Example 1D except that the circuit sheets produced in Examples 2D to 6D were used.

<Example 13D>
A circuit board was produced in the same manner as in Example 1D except that the cushion material was changed to a laminated body (Mitsui Chemicals Higashi Co., Ltd., trade name; Opulan, product number: CR1012MT4).

<Experimental example 1>
A circuit board was produced in the same manner as in Example 1D except that the circuit sheet produced in Comparative Example 1D was used. As a result, although the insulating layer and the circuit sheet were well connected without peeling, there was a part where the insulating material protruded from the circuit on the element mounting surface, and there was no dent in the insulating part. Both workability were inferior to those of the examples.

<Example 1E>
(Circuit fabrication)
A circuit having a width of 3.0 mm, a length of 10 mm, and a height of 2.0 mm was formed by punching with a press using a copper plate having a thickness of 2.0 mm (model number: C1100 1 / 4H).
A protective film in which a 25 μm polyimide film (elastic modulus; 5 GPa) and an adhesive layer (thickness: 10 μm) were laminated was attached to the element mounting surfaces of the formed four circuits.

(Making roughened shape)
A roughening liquid (manufactured by MacDermid Performance Solutions Co., Ltd., trade name; Multibond 150) was used to roughen the surface to which the protective film was not attached. When the surface roughness (Ra) of the circuit after the treatment and the lower surface was measured with a surface roughness meter, both were 1.0 μm (specific surface area; 1.9).

Next, one surface of a 2.0 mm thick copper plate (model number; C1100 1 / 4H) is subjected to the same roughening treatment as above, and the surface roughness (Ra) is 1.0 μm (specific surface area; 1). The copper plate of 9.9) was prepared. A varnish for forming an insulating layer (manufactured by Hitachi Kasei Co., Ltd., HT1500) was applied to the surface subjected to the roughening treatment, and dried to obtain an insulating layer.

The roughened circuit is arranged so that the lower surface is on the insulating layer side, crimped under the conditions of 180 ° C. for 3 hours and 4 MPa, the protective film is peeled off, and the circuit is insulated on the surface opposite to the element mounting surface. A circuit sheet was produced in which the layers were arranged and a part of the side surface of the circuit (up to a height of 150 μm from the lower surface) was covered with an insulating layer. The thickness of the insulating layer was 210 μm. The surface roughness (Ra) of the device mounting surface was 0.1 μm (specific surface area; 1.04).

When a reflow test at 290 ° C. for 10 minutes was carried out on the prepared circuit sheet, no peeling of the insulating layer was observed from the side surface and the lower surface of the circuit. The element mounting was also done well.

<Example 2E>
In Example 1E, the circuit sheet was prepared in the same manner except that the roughening treatment was performed so that the surface roughness (Ra) of the side surface and the lower surface of the circuit was 2.0 μm (specific surface area; 2.6), respectively. Made.
When the prepared circuit sheet was subjected to a reflow test at 290 ° C. for 10 minutes, no peeling of the insulating layer was observed from the side surface and the lower surface of the circuit. The element mounting was also done well.

<Example 3E>
In Example 1E, the circuit sheet was prepared in the same manner except that the roughening treatment was performed so that the surface roughness (Ra) of the side surface and the lower surface of the circuit was 0.65 μm (specific surface area; 1.65), respectively. Made.
When the prepared circuit sheet was subjected to a reflow test at 290 ° C. for 10 minutes, no peeling of the insulating layer was observed from the side surface and the lower surface of the circuit. The element mounting was also done well.

<Example 4E>
After roughening treatment in the same manner as in Example 1E, an epoxy-based insulating material (manufactured by Hitachi Kasei) is filled between circuits at a molding pressure of 7 MPa and a curing time of 300 seconds using a transfer molding machine to insulate. Formed a part. Then, the protective film was peeled off.
Instead of the insulating layer forming varnish used in Example 1E, a resin sheet for forming an insulating layer of the B stage (manufactured by Hitachi Kasei Co., Ltd., HT1500) was used in the same manner as the element mounting surface. A circuit sheet in which an insulating layer was arranged on the surface was produced. The thickness of the finished insulating layer was 205 μm.
When the prepared circuit sheet was subjected to a reflow test at 290 ° C. for 10 minutes, no peeling of the insulating layer from the circuit and peeling from the insulating portion from the circuit were observed. The element mounting was also done well.

<Example 5E>
In Example 4E, a circuit sheet was produced by the same method except that the circuit was formed by etching with an aqueous ferric chloride solution instead of the punching process of the copper plate.
The surface roughness (Ra) of the side surface of the circuit is 1.5 μm (specific surface area; 2.2), and the surface roughness (Ra) of the surface opposite to the device mounting surface is 1.0 μm (specific surface area; 1.9). )Met. The surface roughness (Ra) of the device mounting surface was 0.11 μm (specific surface area; 1.05).
When the prepared circuit sheet was subjected to a reflow test at 290 ° C. for 10 minutes, no peeling of the insulating layer from the circuit and peeling from the insulating portion from the circuit were observed. The element mounting was also done well.

<Example 6E>
All surfaces of the circuit were roughened in the same manner as in Example 1E except that the protective film was not attached to the element mounting surface of the circuit. Then, in the same manner as in Example 1E, a protective film was attached to the element mounting surface of the circuit and crimped to the insulating layer to prepare a circuit sheet. Then, the protective film was peeled off, and electroless Ni plating was applied to the exposed circuit element mounting surface and a part of the side surface not covered with the insulating layer so as to have a thickness of 2.5 μm. The surface roughness (Ra) of the device mounting surface after plating was 0.14 μm (specific surface area; 1.1).
When a reflow test at 290 ° C. for 10 minutes was carried out on the plated circuit sheet, no peeling was observed between the side surface and the lower surface of the circuit and the insulating layer. The element mounting was also done well.

<Comparative Example 1E>
In Example 1E, a circuit sheet was produced by the same method except that the circuit roughening treatment was not performed. The surface roughness (Ra) of the side surface and the lower surface of the circuit is 0.11 μm (specific surface area; 1.05), respectively, and the surface roughness (Ra) of the element mounting surface is also 0.11 μm (specific surface area; 1.05). Met.
When the prepared circuit sheet was subjected to a reflow test at 290 ° C. for 10 minutes, the insulating layer was peeled off from the side surface and the lower surface of the circuit, and the circuit fell off from the insulating layer.

<Comparative Example 2E>
In Example 1E, only the surface opposite to the element mounting surface of the circuit was roughened, and the surface roughness (Ra) of the element mounting surface and the side surface was 0.11 μm (specific surface area; 1.05), respectively. A circuit sheet was produced in the same manner except that a circuit having a surface roughness (Ra) opposite to the device mounting surface of 1.0 μm (specific surface area; 1.9) was used.
When the prepared circuit sheet was subjected to a reflow test at 290 ° C. for 10 minutes, the insulating layer was peeled off from the side surface of the circuit.

[Reference example 1]
A laminate in which an insulating layer and a copper plate having a pressure-sensitive paper provided on a rectangular surface opposite to the base substrate side are laminated in this order on the base substrate is prepared, and the element mounting surface side of the circuit and the laminate are laminated. FIG. 7B shows a state in which a cushioning material facing the base substrate side of the body is arranged, and a spacer member is arranged on the base substrate so as to be in contact with two opposing surfaces in the side surfaces of the circuit and the insulating layer. The laminate was pressurized as described above.

The conditions and pressurization conditions for each member are as follows.
(Conditions for each member)
Base substrate: Material: Copper, Thickness: 2000 μm,
Copper plate: width: 100 mm, length: 50 mm, thickness: 2.0 mm
Insulation layer: Material of insulation material: Hitachi Kasei Co., Ltd., trade name: HT1500, thickness: 210 μm
Spacer member: Material: Copper, Thickness: 50 μm smaller than the total thickness of the copper plate and the insulating layer (pressurization condition)
Pressure: 4 MPa
Heating temperature: 100 ° C
Pressurization time: 5 minutes

For the laminated body after pressurization, the pressure distribution during pressurization, the occurrence of warpage, and the occurrence of delamination were evaluated as follows. The evaluation criteria are as follows, and the results of each evaluation are shown in Table 4.

(Pressure distribution during pressurization)
The pressure distribution on the copper plate was confirmed from the colored state of the pressure-sensitive paper in the laminated body after pressurization. The evaluation criteria are as follows.
Evaluation A ... (Pressure at the lowest pressure point) / (Pressure at the maximum pressure point)> 0.8
Evaluation B: 0.5 <(pressure at the lowest pressure point) / (pressure at the maximum pressure point) ≤ 0.8
Evaluation C ... (pressure at the lowest pressure point) / (pressure at the maximum pressure point) ≤ 0.5

(Occurrence of warpage)
With respect to the laminated body after pressurization, the occurrence of warpage was evaluated by allowing the laminated body to stand on a flat surface and measuring the amount of floating of the laminated body with a thickness gauge. The evaluation criteria are as follows.
Evaluation A: Less than 50 μm Evaluation B: 50 μm or more and less than 70 μm Evaluation C: 70 μm or more

(Occurrence of delamination)
The laminated body after pressurization was evaluated for the occurrence of delamination by an ultrasonic flaw detection method (probe: 25 MHz). The evaluation criteria are as follows.
Evaluation A: No peeling point Evaluation B: Peeling has occurred, but there is no peeling of 0.5 mm or more at maximum Evaluation C: Peeling of 0.5 mm or more has occurred at maximum

[Reference example 2]
Regarding the spacer member arranged on the base substrate so as to be in contact with two opposing surfaces of the side surfaces of the circuit and the insulating layer in Reference Example 1, the thickness of the spacer member is 250 μm smaller than the total thickness of the copper plate and the insulating layer. The same operation as in Reference Example 1 was performed except that it was changed to. The results are shown in Table 4.

[Reference example 3]
The same operation as in Reference Example 1 was performed except that the spacer member was not arranged in Reference Example 1. The results are shown in Table 4.

As shown in Table 4, in Reference Example 1 and Reference Example 2 in which the spacer member was used, the variation in the pressure distribution during pressurization was smaller than that in Reference Example 3 in which the spacer member was not used, and the pressure distribution after pressurization was reduced. With respect to the laminated body, the occurrence of warpage and the occurrence of delamination were suppressed.

[Example 1]
Using the following circuit, insulating layer and heat radiating member, a circuit board in which the circuit, insulating layer and heat radiating member were laminated in this order was prepared.
Circuit: Material: Copper, Thickness: 500 μm, Size: 20 mm x 20 mm (area opposite to the insulating layer), 19.2 mm x 19.2 mm (area on the insulating layer side)
Insulation layer: Material: HT1500 (Hitachi Kasei Co., Ltd.), Thermal conductivity: 10 W / m · K, Thickness: 210 μm, Size: 30 mm × 30 mm
Heat dissipation member: Material: Copper, Thickness: 1000 μm, Size: 30 mm x 30 mm

A heating element is provided on the circuit surface, the temperature is raised at 15 ° C / sec, and when the temperature of the circuit surface reaches 170 ° C, the heat generation is stopped and cooled, and when the temperature drops to 100 ° C on the circuit surface. The cycle of raising the temperature under the above conditions was repeated 250 times.
After that, it was confirmed by ultrasonic flaw detection inspection whether or not the insulating layer was peeled off from the circuit and the heat radiating member. The evaluation criteria are as follows. As a result, in the circuit board of Example 1, the evaluation was A.
Evaluation A: There is no peeling point.
Evaluation B: No peeling of 0.5 mm or more at maximum.
Evaluation C: Peeling of 0.5 mm or more occurs at maximum.

[Example 2]
Using the following circuit, insulating layer and heat radiating member, a circuit board in which the circuit, insulating layer and heat radiating member were laminated in this order was prepared.
Circuit: Material: Copper, Thickness: 2000 μm, Size: 20 mm x 20 mm (area opposite to the insulating layer), 19.2 mm x 19.2 mm (area on the insulating layer side)
Insulation layer: Material: HT1500 (Hitachi Kasei Co., Ltd.), Thermal conductivity: 10 W / m · K, Thickness: 120 μm, Size: 30 mm × 30 mm
Heat dissipation member: Material: Copper, Thickness: 2000 μm, Size: 30 mm x 30 mm
The same cycle test as above was performed. As a result, in the circuit board of Example 2, the evaluation was A.

[Example 3]
Using the following circuit, insulating layer and heat radiating member, a circuit board in which the circuit, insulating layer and heat radiating member were laminated in this order was prepared.
Circuit: Material: Copper, Thickness: 750 μm, Size: 20 mm x 20 mm (area opposite to the insulating layer), 19.2 mm x 19.2 mm (area on the insulating layer side)
Insulation layer: Material: HT1500 (Hitachi Kasei Co., Ltd.), Thermal conductivity: 10 W / m · K, Thickness: 120 μm, Size: 30 mm × 30 mm
Heat dissipation member: Material: Copper, Thickness: 500 μm, Size: 30 mm x 30 mm
The same cycle test as above was performed. As a result, in the circuit board of Example 3, the evaluation was A.

[Comparative Example 1]
Using the following circuit, insulating layer and heat radiating member, a circuit board in which the circuit, insulating layer and heat radiating member were laminated in this order was prepared.
Circuit: Material: Copper, Thickness: 400 μm, Size: 20 mm x 20 mm (area opposite to the insulating layer), 19.2 mm x 19.2 mm (area on the insulating layer side)
Insulation layer: Material: HT1500 (Hitachi Kasei Co., Ltd.), Thermal conductivity: 10 W / m · K, Thickness: 210 μm, Size: 30 mm × 30 mm
Heat dissipation member: Material: Copper, Thickness: 500 μm, Size: 30 mm x 30 mm
The same cycle test as above was performed. As a result, in the circuit board of Comparative Example 1, the evaluation was C.

[Comparative Example 2]
Using the following circuit, insulating layer and heat radiating member, a circuit board in which the circuit, insulating layer and heat radiating member were laminated in this order was prepared.
Circuit: Material: Copper, Thickness: 450 μm, Size: 20 mm x 20 mm (area opposite to the insulating layer), 19.2 mm x 19.2 mm (area on the insulating layer side)
Insulation layer: Material: HT1500 (Hitachi Kasei Co., Ltd.), Thermal conductivity: 10 W / m · K, Thickness: 105 μm, Size: 30 mm x 30 mm
Heat dissipation member: Material: Copper, Thickness: 600 μm, Size: 30 mm x 30 mm
The same cycle test as above was performed. As a result, in the circuit board of Comparative Example 2, the evaluation was C.

[Comparative Example 3]
Using the following circuit, insulating layer and heat radiating member, a circuit board in which the circuit, insulating layer and heat radiating member were laminated in this order was prepared.
Circuit: Material: Copper, Thickness: 1000 μm, Size: 20 mm x 20 mm (area opposite to the insulating layer), 19.2 mm x 19.2 mm (area on the insulating layer side)
Insulation layer: Material: HT1500 (Hitachi Kasei Co., Ltd.), Thermal conductivity: 10 W / m · K, Thickness: 105 μm, Size: 30 mm x 30 mm
Heat dissipation member: Material: Copper, Thickness: 1000 μm, Size: 30 mm x 30 mm
The same cycle test as above was performed. As a result, in the circuit board of Comparative Example 2, the evaluation was C.

1 ... Circuit 2 ... Insulation part 3 ...

Step

10, 20 ...

Circuit sheet

11, 11', 21 ... Circuit 12 ... Insulation layer 13 ...

Heat dissipation member

14, 24 ... Insulation part 15 ...

Cushion material

16, 26 ...

Circuit sheet

110, 120, 130 ... Circuit board A, B ... Outer peripheral edge 31 ... Circuit 32 ... Insulation 33 ... Another circuit 34 ... Highly

elastic member

140, 150, 160 ... Circuit sheet 41 ... Circuit 42 ... Insulation 43 ... Circuit and insulation Part where the parts overlap 170 ... Circuit sheet 51 ... Circuit 52 ... Insulation part 53 ... Insulation layer 180 ... Circuit sheet 70 ...

Circuit sheet

61, 71 ...

Circuit

62, 72 ...

Insulation part

63, 73 ...

Case

64, 74 ...

Heat generator

65, 75 ...

Bonding wire

66, 76 ... Sealing

part

67, 77 ...

Insulation layer

68, 78 ... Heat dissipation member 79 ... Heat conductive sheet 80 ... Base plate 190 ... Circuit sheet with case 101 ... Circuit 102 ...

Insulation layer

103, 104 ... Base board 200, 210 ... Laminated body 105 ... Pressurizing means 106 ...

Cushion material

107, 108 ... Spacer member 112 Circuit 113 Insulation layer 115 Heat dissipation member 220 Circuit board 121 Circuit 122 Insulation layer 230 Circuit sheet 131 Circuit 132 Insulation layer 240 circuit Sheet 141 Circuit 142 Insulation layer 250 Circuit sheet

Claims

A circuit made of a conductor and an insulating portion provided in a space between the circuits are provided, and the side surface between the element mounting surface and the surface opposite to the element mounting surface in the circuit has a step. A circuit sheet in which the step is covered with the insulating portion.
The circuit sheet according to claim 1, wherein the step has a surface parallel to at least one of the element mounting surface and the surface opposite to the element mounting surface.
The circuit sheet according to claim 1 or 2, wherein the circuit has a region in which the cross-sectional shape of the circuit in the thickness direction of the circuit is substantially T-shaped.
The circuit sheet according to any one of claims 1 to 3, wherein the step is provided on the outer periphery of the circuit when viewed in the thickness direction of the circuit.
When viewed in the thickness direction of the circuit, the step is provided inside the circuit, and the insulating portion provided in the space inside the circuit is provided in the space around the circuit. The circuit sheet according to any one of claims 1 to 4, which is connected to the insulating portion at two or more places.
The surface roughness of the side surface is larger than at least one of the surface roughness of the element mounting surface and the surface roughness of the surface opposite to the element mounting surface, according to any one of claims 1 to 5. Circuit sheet.
The circuit sheet according to any one of claims 1 to 6, an insulating layer arranged so as to be in contact with a surface opposite to the element mounting surface, and a heat radiating member arranged so as to be in contact with the insulating layer. And, a circuit board having in this order.
The thickness of the laminated body in which the circuit sheet according to any one of claims 1 to 6, the insulating layer arranged on the surface opposite to the element mounting surface, and the heat radiating member are arranged in this order. A method of manufacturing a circuit board having a step of pressurizing in the longitudinal direction.