JP6575321B2 - Resin composition, circuit board, heating element mounting board, and circuit board manufacturing method - Google Patents

Description

  The present invention relates to a resin composition, a circuit board, a heating element mounting board, and a method for manufacturing a circuit board.

  In recent years, SiC / GaN power semiconductor devices equipped with elements using SiC (silicon carbide) or GaN (gallium nitride) have attracted attention from the viewpoint of effective use of electrical energy (for example, see Patent Document 1). .

  These devices can not only significantly reduce power loss compared to conventional Si-based devices, but can also operate at higher voltages, higher currents, and temperatures as high as 300 ° C. For this reason, it is expected to expand to applications that have been difficult to apply to conventional Si power semiconductor devices.

  In this way, the element (semiconductor element) using SiC / GaN itself can operate under the severe conditions as described above. Therefore, for a circuit board on which a semiconductor device including this element is mounted, heat generated by driving a semiconductor element that is a heating element is applied to the semiconductor element itself and further to other members mounted on the circuit board. On the other hand, it is required to efficiently dissipate heat through the circuit board in order to prevent adverse effects.

  Such a demand is not limited to a semiconductor device, and similarly occurs for a circuit board on which another heating element such as a light emitting element such as a light emitting diode is mounted.

Japanese Patent Laying-Open No. 2005-167035

Regarding the circuit board capable of efficiently radiating heat, the present inventors have derived a circuit board having a specific structure as described later.
That is, in such a circuit board, a heat radiating part for efficiently radiating the heat generated by the heating element mounted on the metal layer is provided, but this heat radiating part is integrated with the insulating part, These form one layer (composite layer).

  As a result, it is possible to effectively dissipate heat only in the part where heat dissipation is required in the circuit board, and since it can be formed with a resin component other than the heat dissipating part in the composite layer described above, the weight of the entire circuit board can also be reduced. It is also possible to plan.

  However, when various elements are mounted on the circuit board, or when the board is mounted on another board, the circuit board needs to be subjected to a reflow process. At that time, there is a concern that separation between the heat radiating portion and the insulating portion in the composite layer may occur.

  From such a background, an object of the present invention is to provide a resin composition capable of exhibiting high reflow resistance with respect to a circuit board having a specific structure.

  The present inventors have found that the cured product of the resin composition constituting the insulating part of the circuit board can solve the above problem by exhibiting a certain behavior when immersed in an etching solution having a specific composition, The present invention has been reached.

That is, according to the present invention,
A circuit board in which a composite layer including an insulating portion and a heat radiating portion, a resin layer and a metal layer are laminated in this order, is a resin composition constituting the insulating portion,
The resin composition was molded under the following conditions to obtain a test piece, which was immersed in an etching solution containing 16.5% by weight cupric chloride, 25% by weight hydrogen chloride, and 25% by weight hydrogen peroxide for 1 hour. Thus, a resin composition is provided in which the absolute value of the weight change rate of the test piece is 0.02% or less.
(Test specimen preparation conditions)
Using a mold having a cavity having a width of 50 mm, a thickness of 3 mm, and a length of 80 mm, the resin composition is molded under conditions of a mold temperature of 170 ° C., a molding pressure of 10 MPa, and a curing time of 180 seconds to obtain a test piece.

Moreover, according to the present invention,
Provided is a circuit board in which a composite layer, an insulating layer formed by curing the resin composition, and a heat radiating portion, a resin layer, and a metal layer are laminated in this order.

Furthermore, according to the present invention,
A heating element mounting board comprising the above circuit board and a heating element is provided.

Furthermore, according to the present invention,
A method of manufacturing a circuit board in which a composite layer including an insulating portion and a heat dissipation portion, a resin layer, and a metal layer are laminated in this order,
The manufacturing method is
Preparing a laminate of the metal layer and the resin layer;
Disposing the heat dissipating part on a part of the surface of the laminate on the resin layer side;
Forming the insulating part with a resin composition in a region where the heat dissipating part is not disposed on the surface of the laminate on the resin layer side;
Including
The resin composition was molded under the following conditions to obtain a test piece, which was immersed in an etching solution containing 16.5% by weight cupric chloride, 25% by weight hydrogen chloride and 25% by weight hydrogen peroxide for 1 hour. A circuit board manufacturing method is provided in which the absolute value of the weight change rate of the test piece is 0.02% or less.
(Test specimen preparation conditions)
Using a mold having a cavity having a width of 50 mm, a thickness of 3 mm, and a length of 80 mm, the resin composition is molded under conditions of a mold temperature of 170 ° C., a molding pressure of 10 MPa, and a curing time of 180 seconds to obtain a test piece.

In the resin composition of the present invention, the absolute value of the weight change rate when immersed in an etching solution having a specific composition is not more than a specific value.
Here, it can be assumed that the resin composition of the present invention is used for a circuit board having a specific structure, and the circuit board is entirely immersed in an etching solution, and then a reflow process is performed. While undergoing such a process, by suppressing the above-mentioned rate of change in weight, the influence of the etching solution slightly contained in the resin layer can be alleviated and the reflow resistance as a circuit board can be improved. It is considered possible.
On the other hand, even if the entire circuit board is not subjected to the process of being immersed in the etching solution as described above, the circuit board to which the resin composition of the present invention is applied can improve the reflow resistance.
That is, in the above test, the resin having a large weight change due to the etching solution is considered to contain a large amount of voids or have a physically and chemically weak region in the resin. That is, even when a process that does not immerse the etching solution in the entire circuit board is performed, it is an effective index for improving reflow resistance to be less than a specific weight change rate in this etching immersion test. Is heading.

It is a longitudinal cross-sectional view which shows the aspect which applied the heat generating body mounting substrate of 1st Embodiment to mounting of a semiconductor device. It is the figure (plan view) seen from the arrow A direction in FIG. It is a figure for demonstrating the manufacturing method of the metal foil tension board | substrate used for manufacture of the heat generating body mounting board | substrate of FIG. It is a figure for demonstrating the manufacturing method of the metal foil tension board | substrate used for manufacture of the heat generating body mounting board | substrate of FIG. It is a longitudinal cross-sectional view which shows the aspect which applied the heat generating body mounting substrate of 2nd Embodiment to mounting of a semiconductor device. It is the figure (plan view) seen from the arrow A direction in FIG. It is a longitudinal cross-sectional view which shows the aspect which applied the heat generating body mounting substrate of 3rd Embodiment to mounting of a semiconductor device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and detailed description thereof is appropriately omitted so as not to overlap.
In the present specification, “to” represents the following from the above unless otherwise specified.

[First Embodiment]
The resin composition according to this embodiment is shown below.
A circuit board in which a composite layer including an insulating portion and a heat radiating portion, a resin layer and a metal layer are laminated in this order, is a resin composition constituting the insulating portion,
The resin composition was molded under the following conditions to obtain a test piece, which was immersed in an etching solution containing 16.5% by weight cupric chloride, 25% by weight hydrogen chloride, and 25% by weight hydrogen peroxide for 1 hour. Thus, a resin composition is provided in which the absolute value of the weight change rate of the test piece is 0.02% or less.
(Test specimen preparation conditions)
Using a mold having a cavity having a width of 50 mm, a thickness of 3 mm, and a length of 80 mm, the resin composition is molded under conditions of a mold temperature of 170 ° C., a molding pressure of 10 MPa, and a curing time of 180 seconds to obtain a test piece.

First, prior to describing the resin composition of the present embodiment, the heating element mounting substrate according to the present embodiment will be described.
In the following, a case where the heating element mounting substrate of the present embodiment is applied to mounting of a semiconductor device including a semiconductor element as a heating element will be described as an example.

<Heat generating board>
FIG. 1 is a longitudinal sectional view showing a first embodiment in which the heating element mounting substrate of this embodiment is applied to mounting of a semiconductor device, and FIG. 2 is a view (plan view) seen from the direction of arrow A in FIG. is there. In the following, for convenience of explanation, the upper side in FIG. 1, the front side in FIG. 2 is also referred to as “up”, the lower side in FIG. 1, and the back side in FIG. In each figure, the heating element mounting substrate and each part thereof are schematically illustrated in an exaggerated manner, and the size and the ratio of the heating element mounting substrate and each part thereof may be different from actual ones.

  A heating element mounting substrate 50 shown in FIGS. 1 and 2 includes a semiconductor device 1 that is a heating element that generates heat when driven, and a circuit board 10 on which the semiconductor device 1 is mounted. In addition to the semiconductor device 1, other electronic components (members) such as resistors and transistors are usually mounted on the circuit board 10, but the description is omitted in FIGS. is doing.

  The semiconductor device 1 is a semiconductor package including a semiconductor element (not shown). A mold part (sealing part) 11 for sealing the semiconductor element (semiconductor chip) and the semiconductor element (semiconductor chip) are electrically connected. And a connection terminal 12 connected thereto.

  In the present embodiment, the semiconductor element is made of SiC (silicon carbide) or GaN (gallium nitride), and the semiconductor element generates heat when driven.

  Moreover, the mold part 11 is normally comprised with the hardened | cured material of various resin materials, and is sealing by surrounding a semiconductor element.

  Furthermore, the connection terminal 12 is composed of, for example, various metal materials such as Cu, Fe, Ni, and alloys thereof, and the terminal included in the semiconductor element and the metal layer 4 included in the circuit board 10 are electrically connected. Yes.

  The circuit board 10 (wiring board) includes a metal layer 4 that electrically connects the semiconductor device 1, and a metal layer provided on the lower surface of the metal layer 4 (surface opposite to the semiconductor device 1; one surface). 4 and a base material (base part) 8 having a flat plate shape (sheet shape) for supporting 4.

  The metal layer 4 is formed in a predetermined pattern, and a terminal (not shown) provided by the formation of this pattern is electrically connected to a connection terminal (terminal) 12 included in the semiconductor device 1, thereby The terminals included in the semiconductor element and the terminals included in the metal layer 4 are electrically connected.

  The metal layer 4 is connected to electronic components including the semiconductor device 1 mounted on the circuit board 10. Further, it has a function as a heat receiving plate that transfers heat generated in the semiconductor device 1 to the lower surface side of the base material 8 and releases it, and is formed by patterning a metal foil 4A included in a metal foil-clad substrate 10A described later. The

  Examples of the constituent material of the metal layer 4 include various metal materials such as copper, a copper-based alloy, aluminum, and an aluminum-based alloy.

  The thermal conductivity in the thickness direction of the metal layer 4 is preferably 3 W / m · K or more and 500 W / m · K or less, preferably 10 W / m · K or more and 400 W / m · K or less. Is more preferable. It can be said that such a metal layer 4 has an excellent thermal conductivity, and heat generated by driving a semiconductor element included in the semiconductor device 1 is transferred to the substrate 8 side through the metal layer 4. It can be transmitted efficiently.

  The substrate 8 is provided on a resin layer 5 having a flat plate shape (sheet shape) and a lower surface (one surface) of the resin layer 5, and a region where the semiconductor device 1 is mounted in a plan view of the substrate 8. The heat radiation part 7 arranged corresponding to the first region 15 (see FIG. 2) to be included, and the resin layer 5 corresponding to the second region 16 (see FIG. 2) excluding the first region 15 And an insulating part 6 for covering.

  The resin layer (bonding layer) 5 is provided on the lower surface of the metal layer 4, that is, provided between the metal layer 4 and the insulating portion 6 and the heat radiating portion 7 located below the metal layer 4. The metal layer 4, the insulating portion 6, and the heat radiating portion 7 are joined via the resin layer 5.

  Moreover, this resin layer 5 has insulation. Thereby, even if it is a case where the thermal radiation part 7 is comprised with a metal material, the insulation state of the metal layer 4 and the thermal radiation part 7 is ensured.

  Furthermore, the resin layer 5 is configured to exhibit excellent thermal conductivity. Thereby, the resin layer 5 can transfer the heat on the semiconductor device 1 (metal layer 4) side to the heat radiating portion 7.

  A resin layer 5 having a high thermal conductivity is preferably used. Specifically, it is preferably 1 W / m · K or more and 15 W / m · K or less, preferably 5 W / m · K or more. More preferably, it is 10 W / m · K or less. As a result, the heat on the semiconductor device 1 side is efficiently transferred to the heat radiating portion 7 by the resin layer 5. Therefore, heat generated by driving the semiconductor element of the semiconductor device 1 can be efficiently transferred to the heat radiating portion 7 through the metal layer 4 and the resin layer 5, so that the heat dissipation efficiency of the heat generated in the semiconductor device 1 can be improved. Improvement is achieved.

The thickness (average thickness) t ₅ of the resin layer 5 is not particularly limited, but as shown in FIG. 1, it is thinner than the thickness t ₇ of the heat radiating portion 7, specifically, about 50 μm to 250 μm. Is preferable, and it is more preferably about 80 μm to 200 μm. Thereby, the thermal conductivity of the resin layer 5 can be improved while ensuring the insulation of the resin layer 5.

  Further, the glass transition temperature of the resin layer 5 is preferably 100 ° C. or higher and 200 ° C. or lower. Thereby, since the rigidity of the resin layer 5 increases and the warp of the resin layer 5 can be reduced, the occurrence of warp in the circuit board 10 can be suppressed.

  In addition, the glass transition temperature of the resin layer 5 can be measured as follows based on JIS C 6481.

  Using a dynamic viscoelasticity measuring device (DMA Instruments' DMA / 983) under a nitrogen atmosphere (200 ml / min), a tensile load was applied, and a frequency of 1 Hz and a temperature of −50 ° C. to 300 ° C. The range is measured at a temperature rising rate of 5 ° C./min, and the glass transition temperature Tg is obtained from the peak position of tan δ.

  The elastic modulus (storage elastic modulus) E ′ at 25 ° C. of the resin layer 5 is preferably 10 GPa or more and 70 GPa or less. Thereby, since the rigidity of the resin layer 5 increases, the curvature produced in the resin layer 5 can be reduced. As a result, the occurrence of warpage in the circuit board 10 can be suppressed.

  The storage elastic modulus can be measured with a dynamic viscoelasticity measuring device. Specifically, the storage elastic modulus E ′ is obtained by applying a tensile load to the resin layer 5, a frequency of 1 Hz, and a heating rate of 5 It is measured as the value of the storage elastic modulus at 25 ° C. when measured from −50 ° C. to 300 ° C. at −10 ° C./min.

  The resin layer 5 having such a function has, for example, a configuration in which a filler is dispersed in a layer formed using a resin material as a main material.

  The resin material exhibits a function as a binder for holding the filler in the resin layer 5, and the filler has a thermal conductivity higher than that of the resin material. By making the resin layer 5 have such a configuration, the thermal conductivity of the resin layer 5 can be increased.

  Such a resin layer 5 is comprised with the solidified material or hardened | cured material formed by solidifying or hardening the resin composition for resin layer formation containing a resin material and a filler mainly. That is, the resin layer 5 is composed of a cured product or a solidified product obtained by forming a resin composition for forming a resin layer into a layer shape.

  The heat radiation part 7 is formed corresponding to the first region 15 including the region where the semiconductor device 1 is mounted on the lower surface (one surface) of the resin layer 5 in a plan view of the base material 8 (resin layer 5). Has been.

  Such a heat radiating portion 7 is a member that radiates heat generated in driving the semiconductor element included in the semiconductor device 1 from the lower surface side of the heat radiating portion 7 (circuit board 10) via the metal layer 4 and the resin layer 5. It functions as a heat sink.

  Therefore, the semiconductor element included in the semiconductor device 1 is configured by using SiC (silicon carbide) or GaN (gallium nitride) as in the present embodiment, and this semiconductor element is driven by the conventional Si. Even if heat having a temperature higher than that of the power semiconductor device is generated, this heat can be radiated from the lower surface side through the heat radiating portion 7. Therefore, adverse effects on the semiconductor element itself and further on other electronic components mounted on the circuit board 10 can be accurately suppressed or prevented.

As shown in FIG. 2, in the present embodiment, the size (area S ₇ ) of the heat radiating portion 7 is larger than the size (area S ₁ ) of the semiconductor device 1 in plan view of the base material 8. It is. That is, the first region 15 where the heat radiating portion 7 is located includes a region where the semiconductor device 1 is mounted. Further, in plan view, the region where the semiconductor device 1 is mounted and the first region 15 where the heat radiating portion 7 is located are each rectangular, and the central portions overlap each other, that is, are arranged concentrically. Yes.

  Thereby, when determining the arrangement position with respect to the thermal radiation part 7 of the semiconductor device 1, the freedom degree of the design at the time of setting the position of the terminal with which the metal layer 4 is provided, for example improves. Moreover, since the heat from the semiconductor device 1 can be diffused and dissipated by the heat dissipating part 7, the heat dissipating efficiency of heat dissipating by the heat dissipating part 7 can be improved.

Further, as shown in FIG. 1, the thickness of the heat radiating part 7 (average thickness) The thickness of t ₇ and the metal layer 4 (average thickness) t ₄ are different from each other, i.e., the heat radiating part 7 The thickness t ₇ is thicker than the thickness t ₄ of the metal layer 4. Thereby, the improvement of the heat radiation efficiency of the heat radiation by the heat radiation part 7 can be achieved reliably.

The thickness _{t 4,} is not particularly limited, for example, 3 [mu] m or more, preferably 120μm or less, 5 [mu] m or more, and more preferably not more than 70 [mu] m. By setting the thickness of the metal layer 4 in such a numerical range, the function as the heat receiving plate can be improved while ensuring the conductivity that functions as the metal layer 4.

The thickness _{t 7,} but are not limited to, for example, 1 mm or more, preferably 3mm or less, 1.5 mm or more, and more preferably not more than 2.5 mm. By setting the thickness of the heat radiating portion 7 in such a numerical range, the function as a heat radiating plate can be improved.

  The heat generated by the semiconductor device 1 is quickly dissipated by the heat dissipating part 7 in combination with the above-described thickness relationship and the inclusion relationship (positional relationship) in plan view. That is, the heat dissipation efficiency is improved.

  As a constituent material of the heat radiating part 7, an organic material and an inorganic material can be used as long as they have high heat dissipation characteristics. Among these, various metal materials such as copper, a copper-based alloy, aluminum, and an aluminum-based alloy are preferable, and aluminum or an aluminum-based alloy is more preferable. Such a metal material has a relatively high thermal conductivity, and the heat radiation efficiency of the heat generated by the semiconductor device 1 can be improved.

  Further, when the heat radiating portion 7 is made of aluminum or an aluminum-based alloy and the metal layer 4 is made of copper or a copper alloy, the metal layer 4 has a higher thermal conductivity than the heat radiating portion 7. As a result, when the heat generated in the semiconductor device 1 is transmitted to the metal layer 4, it quickly reaches the heat radiating portion 7 via the resin layer 5 without diffusing extensively in the metal layer 4. Since the heat that has reached is released to the outside of the heat dissipating part 7 while diffusing in the heat dissipating part 7, the heat dissipation efficiency can be further improved.

  In addition, it is preferable that the heat conductivity of the thermal radiation part 7 is 15 W / m * K or more and 500 W / m * K or less, and is 200 W / m * K (aluminum) or more and 400 W / m * K or less (copper). More preferably.

  The insulating portion 6 is provided on the lower surface of the resin layer 5 and is formed corresponding to the second region 16 excluding the first region 15 in a plan view of the base material 8. That is, it is formed so as to surround the heat radiating portion 7 so as to cover the second region 16 where the heat radiating portion 7 on the lower surface of the resin layer 5 is not located.

  Thereby, the insulation in the 2nd area | region 16 in which the thermal radiation part 7 of the lower surface of the base material 8 is not located is ensured. Moreover, the intensity | strength as the base material 8 whole is ensured.

  Moreover, the insulation part 6 has a heat insulation effect. Therefore, the heat radiated by the heat radiating portion 7 can be blocked by the insulating portion 6. Therefore, it is possible to accurately suppress or prevent the adverse effect caused by the transfer of this heat to other electronic components mounted on the metal layer 4 (circuit board 10) located in the second region 16. be able to.

Incidentally, as shown in FIG. 1, the thickness of the heat radiating part 7 (average thickness) t ₇ and the thickness of the insulating part 6 (average thickness), it has a same, thereby, the lower surface of the heat radiating part 7 A flat surface is formed by the lower surface of the insulating portion 6.

  In this embodiment, the insulating portion 6 of the circuit board 10 is formed of a cured product of a resin composition for forming an insulating portion that satisfies specific conditions described later.

  By configuring the insulating part 6 with such a cured product, the difference in the coefficient of thermal expansion between the resin layer 5 and the insulating part 6 can be set small. Accordingly, when the semiconductor element of the semiconductor device 1 is driven, the semiconductor device 1 itself generates heat, and the resin layer 5 and the insulating portion 6 are heated. However, the warp between the resin layer 5 and the insulating portion 6 occurs. It is possible to accurately suppress or prevent the occurrence of peeling due to this.

The heating element mounting substrate 50 shown in FIG. 1 in which the semiconductor device 1 is mounted as a heating element as described above can be obtained by mounting the semiconductor device 1 on the circuit board 10. Instead of the metal layer 4, a metal foil 4 </ b> A having a flat plate shape (sheet shape) can be obtained using a metal foil-clad substrate 10 </ b> A provided on the upper surface (the other surface) of the base material 8.
Hereinafter, a method for manufacturing the circuit board 10 will be described.

(Circuit board manufacturing method)
3 and 4 are views for explaining a method of manufacturing a circuit board (metal foil-clad substrate) used for manufacturing the heating element mounting substrate of FIG. In the following, for convenience of explanation, the upper side in FIGS. 3 and 4 is also referred to as “upper” and the lower side is also referred to as “lower”. In addition, the metal foil-clad substrate and each part thereof are schematically illustrated in an exaggerated manner, and the size and the ratio of the metal foil-clad substrate and each part thereof are greatly different from actual ones.

That is, the manufacturing method of the circuit board according to the present embodiment is as follows.
A method of manufacturing a circuit board in which a composite layer including an insulating portion and a heat dissipation portion, a resin layer, and a metal layer are laminated in this order,
The manufacturing method is
Preparing a laminate of the metal layer and the resin layer;
Disposing the heat dissipating part on a part of the surface of the laminate on the resin layer side;
Forming the insulating part with a resin composition in a region where the heat dissipating part is not disposed on the surface of the laminate on the resin layer side;
Including
The resin composition was molded under the following conditions to obtain a test piece, which was immersed in an etching solution containing 16.5% by weight cupric chloride, 25% by weight hydrogen chloride and 25% by weight hydrogen peroxide for 1 hour. A method of manufacturing a circuit board, wherein the absolute value of the rate of change in weight of the test piece is 0.02% or less.
(Test specimen preparation conditions)
Using a mold having a cavity having a width of 50 mm, a thickness of 3 mm, and a length of 80 mm, the resin composition is molded under conditions of a mold temperature of 170 ° C., a molding pressure of 10 MPa, and a curing time of 180 seconds to obtain a test piece.

[1]
First, in the said manufacturing method, the laminated body of a metal layer and a resin layer is prepared.
Specifically, a flat metal foil 4A is prepared, and then a resin layer forming layer 5A is formed on the metal foil 4A as shown in FIG.

  This resin layer forming layer 5A is obtained by supplying a resin composition for forming a resin layer having a varnish shape, which will be described later, onto the metal foil 4A, and then drying the layered resin composition. And this resin layer formation layer 5A turns into the resin layer 5 by hardening or solidifying through the process [2] and process [3] which are mentioned later.

  The resin composition for forming a resin layer can be supplied to the metal foil 4A using, for example, a comma coater, a die coater, a gravure coater, or the like.

The resin composition for forming a resin layer preferably has the following viscosity behavior.
That is, when the resin composition for forming a resin layer is heated from 60 ° C. to a molten state at a rate of temperature increase of 3 ° C./min and a frequency of 1 Hz using a dynamic viscoelasticity measuring apparatus, the melt viscosity initially decreases. In addition, after reaching the minimum melt viscosity, it has a characteristic of further increasing, and the minimum melt viscosity is preferably in the range of 1 × 10 ³ Pa · s to 1 × 10 ⁵ Pa · s. .

  When the minimum melt viscosity is not less than the above lower limit value, the resin material and the filler can be separated, and only the resin material can be prevented from flowing, and more homogeneous by passing through the steps [2] and [3]. The resin layer 5 can be obtained. Moreover, the wettability to the metal foil 4A of the resin composition for resin layer formation can be improved as minimum melt viscosity is below the said upper limit, and the adhesiveness of the resin layer 5 and metal foil 4A can be improved further.

  These synergistic effects can further improve the heat dissipation and dielectric breakdown voltage of the metal foil-clad substrate 10A (circuit board 10).

  Further, the resin composition for forming a resin layer preferably has a temperature at which the minimum melt viscosity is reached within a range of 60 ° C. or higher and 100 ° C. or lower, more preferably within a range of 75 ° C. or higher and 90 ° C. or lower. preferable.

  Furthermore, the resin composition for forming a resin layer preferably has a flow rate of 15% or more and less than 60%, and more preferably 25% or more and less than 50%.

This flow rate can be measured by the following procedure. That is, first, 5-7 sheets of metal foil having a resin layer formed by the resin composition for forming a resin layer of the present embodiment are cut into a predetermined size (50 mm × 50 mm), and the weight is measured. Next, after pressing for 5 minutes between hot plates maintained at an internal temperature of 175 ° C. and cooling, the resin that has flowed out is carefully dropped and the weight is measured again. The flow rate can be obtained by the following formula (I).
Flow rate (%) = 100 × (weight before measurement−weight after measurement) / (weight before measurement−weight of metal foil) (I)

  With such a viscosity behavior, when the resin composition for forming a resin layer is heated and cured to form the resin layer 5, it is possible to further suppress the intrusion of air into the resin composition for forming a resin layer, The gas dissolved in the resin composition for forming a resin layer can be discharged more fully to the outside. As a result, generation of bubbles in the resin layer 5 can be suppressed, and heat can be reliably transmitted from the metal foil 4 </ b> A to the resin layer 5. Further, by suppressing the generation of bubbles, the insulation reliability of the metal foil-clad substrate 10A (circuit board 10) can be enhanced. Moreover, the adhesiveness of the resin layer 5 and metal foil 4A can be improved.

  These synergistic effects can further improve the heat dissipation of the metal foil-clad substrate 10A (circuit board 10), and as a result, the heat cycle characteristics of the metal foil-clad substrate 10A can be further improved.

  The resin composition for forming a resin layer having such a viscosity behavior includes, for example, the type and amount of a resin material, the type and amount of a filler, and, if the resin material contains a phenoxy resin, the type and amount of the resin material. It can be obtained by adjusting appropriately. In particular, the use of an epoxy resin having good fluidity such as a naphthalene type epoxy resin makes it easy to obtain the above viscosity characteristics.

[2]
Subsequently, a heat dissipating part is disposed on a part of the surface of the laminated body on the resin layer side.
Specifically, the heat radiating portion 7 is prepared, and then, as shown in FIG. 3B, the metal foil 4A and the heat radiating portion 7 are pressurized so as to approach each other via the resin layer forming layer 5A. Heat with.
Thereby, the heat radiation part 7 is bonded to the resin layer forming layer 5 </ b> A corresponding to the first region 15 (see FIG. 3C).

  At this time, when the resin layer forming layer 5A exhibits thermosetting properties, the resin layer forming layer 5A is preferably heated and pressurized under conditions of uncured or semi-cured, more preferably semi-cured. The When the resin layer forming layer 5A exhibits thermoplasticity, the resin layer forming layer 5A is heated and pressurized under the condition of being solidified by cooling after being melted by heating and heating.

  The heating and pressurizing conditions vary depending on, for example, the type of resin composition for forming a resin layer contained in the resin layer forming layer 5A, but are set as follows.

  That is, the heating temperature is preferably set to about 80 to 200 ° C, more preferably about 170 to 190 ° C.

  Moreover, the pressure to pressurize becomes like this. Preferably it is about 0.1-3 MPa, More preferably, it is set to about 0.5-2 MPa.

  Furthermore, the heating and pressurizing time is preferably about 10 to 90 minutes, more preferably about 30 to 60 minutes.

  Thereby, the lower surface of the heat radiating portion 7 is bonded to the resin layer forming layer 5A, and as a result, the heat radiating portion 7 is bonded to the resin layer forming layer 5A.

  When the resin layer forming layer 5A exhibits thermosetting properties, the selection of whether the resin layer forming layer 5A is uncured or semi-cured is, for example, the resin layer forming layer 5A in this step [2]. When giving priority to the bonding of the heat radiating part 7 to the resin layer, the resin layer forming layer 5A is set in a semi-cured state to improve the adhesion at the interface between the resin layer 5 and the insulating part 6 in the next step [3]. When giving priority to this, the resin layer forming layer 5A may be in an uncured state.

[3]
Furthermore, an insulating part is formed with the resin composition in the area | region where the thermal radiation part is not arrange | positioned of the surface at the side of the resin layer of the laminated body mentioned above.
That is, the insulating portion 6 is formed on the resin layer forming layer 5A so as to surround the heat radiating portion 7 in a plan view of the resin layer forming layer 5A. In other words, the insulating portion 6 is formed so as to cover the second region 16 where the heat radiating metal plate 7 is not located on the upper surface of the resin layer forming layer 5A.

  Further, at this time, if the resin layer forming layer 5A exhibits thermosetting properties, the resin layer forming layer 5A is cured to form the resin layer 5, and the resin layer forming layer 5A is thermoplastic. In this case, the resin layer 5 is formed by solidifying again after melting (see FIG. 3D).

  The method for forming the insulating portion 6 is not particularly limited. For example, the second region where the heat radiating portion 7 on the upper surface of the resin layer forming layer 5A is not located in a state where the resin composition for forming the insulating portion is melted. After supplying to the upper surface side of 5 A of resin layer forming layers so that 16 may be covered, the method of shape | molding this resin composition for insulating part formation of a molten state is mentioned. According to such a method, the insulating portion 6 can be formed in a position-selective manner with excellent accuracy with respect to the second region 16 on the upper surface of the resin layer forming layer 5A.

Hereinafter, the case where the insulating part 6 is formed by this method will be described in detail with reference to FIG.
In addition, as the resin composition for forming an insulating portion, any of a granular shape (pellet shape), a sheet shape, a strip shape, or a tablet shape may be used, but in the following, a tablet shape is used. Will be described as an example.

  [3-1] First, a heat radiating part joined on the resin layer forming layer 5A to a cavity (storage space) 121 formed by overlapping the upper mold 110 and the lower mold 120 provided in the molding die 100. 7 is stored so that the heat dissipating part 7 is on the upper side, and then the upper mold 110 and the lower mold 120 are clamped. At this time, the lower opening of the supply path 113 and the heat dissipating part 7 do not overlap in the thickness direction of the heat dissipating part 7, and the lower surface of the upper mold 110 and the upper surface of the heat dissipating part 7 are in contact with each other. Then, the heat radiating part 7 bonded on the resin layer forming layer 5 </ b> A is accommodated in the cavity 121. Thereby, the insulating part 6 formed in a post process can be formed as the thickness of the insulating part 6 is the same as the thickness of the heat radiating part 7. That is, the insulating portion 6 is not formed on the upper surface of the heat radiating portion 7, and the upper surface of the insulating portion 6 and the upper surface of the heat radiating portion 7 constitute a flat surface. The second region 16 can be selectively provided.

  And the resin composition 130 for insulating part formation which makes tablet shape is accommodated in the pot 111 with which the upper mold | type 110 is provided.

  [3-2] Next, the insulating mold is formed by inserting the plunger 112 into the pot 111 while heating and melting the insulating mold forming resin composition 130 in the pot 111 by heating the molding die 100. The resin composition 130 is pressurized.

  Thereby, the molten resin composition 130 for forming an insulating part is transferred into the cavity 121 through the supply path 113.

  [3-3] Next, by inserting the plunger 112 into the pot 111, the metal foil 4 </ b> A accommodated in the cavity 121 is heated and pressurized and melted in a molten state. 130 is filled in the cavity 121 so as to cover the resin layer forming layer 5 </ b> A located in the second region 16.

  Then, the insulating part 6 is formed by curing the melted resin composition 130 for forming the insulating part, so that the insulating part 6 is formed so as to surround the heat radiating part 7 in a plan view of the resin layer forming layer 5A. Is done.

  Further, when the resin layer forming layer 5A exhibits thermosetting properties by this heating and pressurization, the resin layer 5 is formed by curing the resin layer forming layer 5A, and the resin layer forming layer 5A exhibits thermoplasticity. In this case, after the material is melted, the resin layer 5 is formed by cooling and solidifying again.

  The heating and pressurizing conditions in this step are not particularly limited, but are set as follows, for example.

  That is, the heating temperature is preferably set to about 80 to 200 ° C, more preferably about 170 to 190 ° C.

  Moreover, the pressure to pressurize becomes like this. Preferably it is about 2-10 Mpa, More preferably, it is set to about 3-7 Mpa.

  Furthermore, the heating and pressurizing time is preferably about 1 to 60 minutes, and more preferably about 3 to 15 minutes.

  Assuming a system in which a filler is included in the resin composition forming the resin layer 5, the filler contained in the resin layer 5 is changed to an insulating part at the interface between the resin layer 5 and the insulating part 6 by setting to such conditions. Since the resin layer 5 and the insulating portion 6 are formed in a state where the resin layer 5 and the insulating portion 6 are mixed and dispersed on the 6 side, the adhesion between the resin layer 5 and the insulating portion 6 can be improved. it can.

  In addition, the melt viscosity of the insulating portion forming resin composition 130 is preferably about 10 to 3000 Pa · s, more preferably about 30 to 2000 Pa · s at 175 ° C. Thereby, the insulating part 6 can be more reliably formed so as to surround the heat radiating part 7 in a plan view of the resin layer 5.

  The melt viscosity at 175 ° C. can be measured by, for example, a thermal fluidity evaluation apparatus (flow tester) manufactured by Shimadzu Corporation.

In addition, it is preferable that the metal foil 4 </ b> A is pressed against the bottom surface of the cavity 121 provided in the lower mold 120 by the pressure generated by inserting the plunger 112 into the pot 111. Thereby, wraparound of the molten insulating part forming resin composition 130 to the lower surface of the metal foil 4A is prevented. As a result, the formation of the insulating portion 6 on the lower surface of the metal foil 4A is accurately prevented. Therefore, it is possible to prevent the wiring 4 obtained by patterning the metal foil 4 </ b> A from being covered with the insulating portion 6 and hindering electrical connection with the electronic component including the semiconductor device 1.
The metal foil-clad substrate 10A is manufactured through the steps as described above.

  Moreover, the circuit board 10 in which the metal layer 4 is formed on the base material 8 is manufactured by patterning the metal foil 4A included in the metal foil-clad substrate 10A. The method for patterning the metal foil 4A is not particularly limited. For example, after a resist layer corresponding to the pattern (shape) of the metal layer 4 to be formed is formed on the metal foil 4A, the resist layer is masked. And a method of etching the metal foil 4A exposed from the opening of the resist layer by a wet etching method or a dry etching method.

  In addition, although this embodiment demonstrated the case where one metal foil tension board | substrate 10A was obtained by passing through the said process [3-1]-[3-3], it is not limited to this case, For example, the said In step [3-1], a plurality of heat radiation portions 7 bonded on the resin layer forming layer 5A are accommodated in the cavity 121, and then through the steps [3-2] and [3-3]. You may make it take many metal foil tension board | substrates 10A by cutting (cutting) the obtained thing in the thickness direction. In this cutting, (I) after the step [3-3], (II) after the metal foil 4A is patterned to form a plurality of metal layers 4 on the substrate 8, and further (III) Although it may be any after mounting the plurality of semiconductor devices 1 corresponding to the plurality of metal layers 4, respectively, it is preferable to be after (III). Thereby, the several heat generating body mounting board | substrate 50 can be manufactured collectively.

  In the present embodiment, the step [2] and the step [3] are performed in separate steps. However, the present invention is not limited to this. For example, the resin composition 130 for forming an insulating portion in the pot 111 is used. If it is possible to press the metal foil 4A of the heat radiating portion 7 by inserting the plunger 112 into the pot 111 in a state where the loading is omitted, the steps [2] and [3] are performed. Alternatively, it may be performed collectively in the cavity 121.

  The heating element mounting substrate 50 having such a configuration is mounted as a substrate (one component) included in various electronic devices.

  Hereinafter, the resin composition which comprises the circuit board 10 mentioned above is demonstrated. More specifically, in producing the circuit board 5, a resin composition for forming the resin layer 5 and a resin composition for forming the insulating portion 6 are used. These resin compositions will be described below.

(Resin composition for resin layer formation)
First, the resin composition for forming a resin layer will be described.
The resin composition for forming a resin layer includes, for example, a resin material and a filler.

  The resin material is not particularly limited, and various resin materials such as a thermoplastic resin and a thermosetting resin can be used.

  Examples of the thermoplastic resin include polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer, modified polyolefins, polyamides (eg, nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12). , Nylon 6-12, nylon 6-66), thermoplastic polyimide, aromatic polyester and other liquid crystal polymers, polyphenylene oxide, polyphenylene sulfide, polycarbonate, polymethyl methacrylate, polyether, polyether ether ketone, polyether imide, polyacetal, Styrene, polyolefin, polyvinyl chloride, polyurethane, polyester, polyamide, polybutadiene, trans polyisoprene, fluoro rubber, salt Various thermoplastic elastomers, etc., or a copolymer of these His polyethylene type or the like, blends, polymer alloys and the like, can be used as a mixture of two or more of them.

  On the other hand, examples of the thermosetting resin include epoxy resin, phenol resin, urea resin, melamine resin, polyester (unsaturated polyester) resin, polyimide resin, silicone resin, polyurethane resin, and the like. Or 2 or more types can be mixed and used.

  Among these, as a resin material used for the resin composition for forming a resin layer, it is preferable to use a thermosetting resin, and it is more preferable to use an epoxy resin. Thereby, the heat resistance of the resin layer 5 obtained can be made excellent. Further, the metal layer 4 can be firmly bonded to the substrate 8 by the resin layer 5. Therefore, the heat dissipation and durability of the resulting heating element mounting substrate 50 can be made excellent.

  Moreover, it is preferable that an epoxy resin contains the epoxy resin (A) which has at least any one of an aromatic ring structure and an alicyclic structure (alicyclic carbocyclic structure). By using such an epoxy resin (A), the glass transition temperature can be increased and the thermal conductivity of the resin layer 5 can be further improved. Moreover, the adhesiveness with respect to the metal layer 4, the insulation part 6, and the thermal radiation part 7 can be improved.

  Furthermore, as an epoxy resin (A) having an aromatic ring or alicyclic structure, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, bisphenol M type epoxy resin, Bisphenol P type epoxy resin, bisphenol type epoxy resin such as bisphenol Z type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, novolak type epoxy resin such as tetraphenol group ethane type novolak type epoxy resin, biphenyl type epoxy resin , Arylalkylene type epoxy resins such as phenol aralkyl type epoxy resins having a biphenylene skeleton, and epoxy resins such as naphthalene type epoxy resins. It can be used in combination of at least Chino one or.

  The epoxy resin (A) is preferably a naphthalene type epoxy resin. Thereby, a glass transition temperature can be made still higher, generation | occurrence | production of the void of the resin layer 5 can be suppressed, thermal conductivity can be improved further, and a dielectric breakdown voltage can be improved.

  The naphthalene type epoxy resin is one having a naphthalene ring skeleton and having two or more glycidyl groups.

  Thus, when a naphthalene type epoxy resin is included, the content of the naphthalene type epoxy resin in the epoxy resin is preferably 20% by mass or more and 80% by mass or less, more preferably 40% by mass with respect to 100% by mass of the epoxy resin. It is not less than 60% by mass.

  Examples of the naphthalene type epoxy resin include any of the following formulas (5) to (8).

［式中、ｍ、ｎはナフタレン環上の置換基の個数を示し、それぞれ独立して１〜７の整数を示す。］

[Wherein, m and n represent the number of substituents on the naphthalene ring, and each independently represents an integer of 1 to 7. ]

  In addition, as a compound of Formula (6), it is preferable to use any 1 or more types of the following.

［式中、Ｍｅはメチル基を示し、ｌ、ｍ、ｎは１以上の整数を示す。］

[Wherein, Me represents a methyl group, and l, m, and n represent an integer of 1 or more. ]

［式中、ｎは１以上２０以下の整数であり、ｌは１以上２以下の整数であり、Ｒ_１はそれぞれ独立に水素原子、ベンジル基、アルキル基または下記式（９）で表される構造であり、Ｒ_２はそれぞれ独立に水素原子またはメチル基である。］

[Wherein, n is an integer of 1 or more and 20 or less, l is an integer of 1 or more and 2 or less, and each R ₁ is independently represented by a hydrogen atom, a benzyl group, an alkyl group or the following formula (9). And R ₂ is independently a hydrogen atom or a methyl group. ]

［式中、Ａｒはそれぞれ独立にフェニレン基またはナフチレン基であり、Ｒ_２はそれぞれ独立に水素原子またはメチル基であり、ｍは１または２の整数である。］

[Wherein, Ar is each independently a phenylene group or a naphthylene group, R ₂ is each independently a hydrogen atom or a methyl group, and m is an integer of 1 or 2. ]

  The naphthalene type epoxy resin of the formula (8) is classified as a so-called naphthylene ether type epoxy resin, and the compound represented by the formula (8) is exemplified by those represented by the following formula (10). It is done.

［上記式（１０）において、ｎは１以上２０以下の整数であり、好ましくは１以上１０以下の整数であり、より好ましくは１以上３以下の整数である。Ｒはそれぞれ独立に水素原子または下記式（１１）で表される構造であり、好ましくは水素原子である。］

[In the above formula (10), n is an integer of 1 or more and 20 or less, preferably an integer of 1 or more and 10 or less, more preferably an integer of 1 or more and 3 or less. Each R is independently a hydrogen atom or a structure represented by the following formula (11), preferably a hydrogen atom. ]

［上記式（１１）において、ｍは１または２の整数である。］

[In the above formula (11), m is an integer of 1 or 2. ]

  Furthermore, specific examples of the naphthylene ether type epoxy resin represented by the above formula (10) include those represented by the following formulas (12) to (16).

  Further, the content of the resin material is preferably 20 parts by mass or more and 100 parts by mass or more with respect to 100 parts by mass of the entire solid content (excluding the solvent) of the resin composition for resin layer formation. Is more preferable. Further, the content of the resin material is preferably 80 parts by mass or less, and 70 parts by mass or less with respect to 100 parts by mass of the entire solid content (excluding the solvent) of the resin composition for resin layer formation. Is more preferable. By setting the content of the resin material to be equal to or higher than the lower limit value, adhesion to the metal layer 4, the insulating portion 6, and the heat radiating portion 7 can be improved. Moreover, the mechanical strength and heat conductivity of the resin layer 5 obtained can be made excellent by making content of a resin material below this upper limit.

  Moreover, when a resin material contains an epoxy resin, it is preferable that the resin composition for resin layer formation contains the phenoxy resin. Thereby, since the bending resistance of the resin layer 5 can be improved, the handleability fall of the resin layer 5 by highly filling a filler can be suppressed.

  In addition, when the phenoxy resin is included, the fluidity at the time of pressing is reduced due to an increase in viscosity, and the resin layer 5 thickness is ensured, and the thickness uniformity and void suppression are effective. Therefore, insulation reliability and thermal conductivity are further improved. Can be increased. In addition, adhesion between the resin layer 5 and the metal layer 4, the heat radiating portion 7, and the insulating portion 6 is improved. By these synergistic effects, the insulation reliability and thermal conductivity of the heating element mounting substrate 50 can be further enhanced.

  Examples of the phenoxy resin include a phenoxy resin having a bisphenol skeleton, a phenoxy resin having a naphthalene skeleton, a phenoxy resin having an anthracene skeleton, and a phenoxy resin having a biphenyl skeleton. A phenoxy resin having a structure having a plurality of these skeletons can also be used.

  Among these, it is preferable to use bisphenol A type or bisphenol F type phenoxy resin. A phenoxy resin having both a bisphenol A skeleton and a bisphenol F skeleton may be used.

The weight average molecular weight of the phenoxy resin is not particularly limited, but is preferably 4.0 × 10 ⁴ or more and 8.0 × 10 ⁴ or less.

  In addition, the weight average molecular weight of a phenoxy resin is a value in terms of polystyrene measured by gel permeation chromatography (GPC).

  The content of the phenoxy resin is, for example, preferably 1 part by mass or more and 50 parts by mass or less, more preferably 2 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass as a whole of the solid content of the resin composition for resin layer formation. .

  In addition, the resin composition for forming a resin layer includes a curing agent as necessary depending on the type of the resin material described above (for example, in the case of an epoxy resin).

  The curing agent is not particularly limited, and examples thereof include amide curing agents such as dicyandiamide and aliphatic polyamide, amine curing agents such as diaminodiphenylmethane, methanephenylenediamine, ammonia, triethylamine, and diethylamine, bisphenol A, and bisphenol F. And phenolic curing agents such as phenol novolac resin, cresol novolak resin, p-xylene-novolak resin, and acid anhydrides.

  Moreover, the resin composition for forming a resin layer may further contain a curing catalyst (curing accelerator). Thereby, the sclerosis | hardenability of the resin composition for resin layer formation can be improved.

  Examples of the curing catalyst include amine catalysts such as imidazoles, 1,8-diazabicyclo [5.4.0] undecene, phosphorus catalysts such as triphenylphosphine, and the like. Of these, imidazoles are preferred. Thereby, especially the quick-hardening property and the preservability of the resin composition for resin layer formation can be made compatible.

  Examples of imidazoles include 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1 -Cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2' -Undecylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4'methylimidazolyl- (1')]-ethyl-s-triazine, 2, 4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimid Zole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,4-diamino-6-vinyl-s-triazine, 2,4- Diamino-6-vinyl-s-triazine isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-s-triazine, 2,4-diamino-6-methacryloyloxyethyl-s-triazine isocyanuric acid adduct, etc. Is mentioned. Among these, 2-phenyl-4,5-dihydroxymethylimidazole or 2-phenyl-4-methyl-5-hydroxymethylimidazole is preferable. Thereby, especially the preservability of the resin composition for resin layer formation can be improved.

Moreover, the content of the curing catalyst is not particularly limited, but is preferably about 0.01 to 30 parts by mass, more preferably about 0.5 to 10 parts by mass with respect to 100 parts by mass of the resin material. preferable.
By setting the content of the curing catalyst within the above range, it is possible to provide good curability for the resin composition for forming a resin layer, and at the same time, it is possible to provide moderate preservability for the composition.

  Moreover, it is preferable that the resin composition for resin layer formation contains a coupling agent further. Thereby, the adhesiveness of the resin material with respect to a filler, the insulation part 6, the thermal radiation part 7, and the metal layer 4 can be improved more.

  Examples of such coupling agents include silane coupling agents, titanium coupling agents, aluminum coupling agents, and the like. Of these, silane coupling agents are preferred. Thereby, the heat resistance and heat conductivity of the resin composition for forming a resin layer can be further improved.

  Of these, examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane. , Γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyl Methyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane Lan, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, bis (3 -Triethoxysilylpropyl) tetrasulfane and the like.

Although content of a coupling agent is not specifically limited, It is preferable that it is about 0.01-10 mass parts with respect to 100 mass parts of resin materials, and it is more preferable that it is especially about 0.5-10 mass parts. .
By setting the content of the silane coupling agent in the above range, the resin composition for forming a resin layer can have good heat resistance and thermal conductivity, and at the same time, it can suppress voids generated from the resin component. it can.

  Moreover, the filler in the resin composition for resin layer formation is comprised with an inorganic material. Thereby, a filler exhibits heat conductivity higher than the heat conductivity of a resin material. Therefore, the thermal conductivity of the resin layer 5 can be increased by dispersing the filler in the resin composition for forming a resin layer.

Such filler is preferably a granular material composed of at least one of aluminum oxide (alumina, Al ₂ O ₃ ), silica, boron nitride and aluminum nitride among those composed of inorganic materials. In particular, a granular body mainly composed of aluminum oxide is preferable. Thereby, it can be set as the resin composition excellent in thermal conductivity (heat dissipation) and insulation. Aluminum oxide is particularly preferably used because it is highly versatile and can be obtained at low cost.

  Therefore, hereinafter, a case where the filler is a granular body mainly composed of aluminum oxide will be described as an example.

  The content of the filler is preferably 20 parts by mass or more and 80 parts by mass or less, and 30 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass of the entire solid content (excluding the solvent) of the resin composition for resin layer formation. It is more preferable that By making the content rate of the filler in the resin composition for resin layer formation high like this range, the thermal conductivity of the resin layer 5 can be made more excellent.

  Even if the filler content in the resin composition for forming a resin layer is set high as in the above range, the resin composition for forming a resin layer has a temperature of 25 ° C. and a shear rate of 1.0 rpm. 2. A / B (thixo ratio) is 1.2 or more when the viscosity is A [Pa · s], the viscosity at a temperature of 25 ° C. and a shear rate of 10.0 rpm is B [Pa · s]. By using a material that satisfies a relationship of 0 or less, the viscosity and flowability of the resin composition for forming a resin layer (varnish) should be appropriate when the circuit board 10 (metal foil-clad substrate 10A) is manufactured. Can do.

  The filler can be used after washing. When the filler is washed in this way, it is preferable to perform sufficient drying. Here, the water content of the filler after drying is preferably 0.10% by mass to 0.30% by mass, more preferably 0.10% by mass to 0.25% by mass, More preferably, it is 0.12 mass% or more and 0.20 mass% or less. Thereby, even if the content of the filler is increased, it has a more appropriate viscosity and flowability. Therefore, the resin layer 5 excellent in thermal conductivity can be formed while preventing generation of voids in the obtained resin layer 5. That is, the resin layer 5 having excellent thermal conductivity and insulation can be formed.

  Aluminum oxide is usually obtained by firing aluminum hydroxide. The obtained aluminum oxide granules are composed of a plurality of primary particles, and the average particle size of the primary particles can be set according to the firing conditions.

  Moreover, the aluminum oxide which has not been treated at all after the firing is composed of aggregates (secondary particles) in which primary particles are aggregated due to fixation.

  Therefore, the final filler can be obtained by solving the aggregation of the primary particles as necessary by pulverization. The average particle diameter of the final filler can be set according to the pulverization conditions (for example, time).

  During the pulverization, the aluminum oxide has a very high hardness, so the primary particles themselves are hardly broken, and the average particle size of the primary particles is almost maintained even after pulverization. The Rukoto.

  Therefore, as the grinding time becomes longer, the average particle size of the filler approaches the average particle size of the primary particles. And when grinding | pulverization time becomes more than predetermined time, the average particle diameter of a filler will become equal to the average particle diameter of a primary particle. That is, the filler is mainly composed of secondary particles when the grinding time is shortened, and the content of primary particles increases as the grinding time is lengthened. It will be.

  Further, for example, primary particles of aluminum oxide obtained by firing aluminum hydroxide as described above have a shape having a flat surface such as a scaly shape instead of a spherical shape. Therefore, the contact area between fillers can be increased. As a result, the thermal conductivity of the obtained resin layer 5 can be increased.

  The filler contained in the resin composition for forming a resin layer has an average particle size in the range of 1.0 μm to 50 μm, preferably 1.5 μm to 30 μm. Thereby, the moderate heat dissipation as the moderate resin layer 5 can be brought about.

  The particle diameter of the filler can be measured by dispersing the filler in water by ultrasonic treatment for 1 minute using a laser diffraction particle size distribution analyzer SALD-7000.

  By these synergistic effects, the insulation reliability and heat radiation reliability of the heating element mounting substrate 50 can be further enhanced.

  In addition, the resin composition for forming a resin layer may contain additives such as a leveling agent and an antifoaming agent in addition to the components described above.

  Moreover, the resin composition for resin layer formation contains solvents, such as methyl ethyl ketone, acetone, cyclohexanone, toluene, dimethylformaldehyde, for example. Thereby, the resin composition for resin layer formation will be in a varnish state, when resin material etc. melt | dissolve in a solvent.

  Such a resin composition for forming a resin layer having a varnish shape can be obtained, for example, by mixing a resin material and a solvent as necessary to make a varnish shape, and further mixing a filler. it can.

  The mixer used for mixing is not particularly limited, and examples thereof include a disperser, a composite blade type stirrer, a bead mill, and a homogenizer.

  In addition, when the resin material has high thermal conductivity, you may make it abbreviate | omit the addition of the filler to the resin composition for resin layer formation. That is, the resin layer 5 may be mainly composed of a resin material in which the addition of filler is omitted.

  On the other hand, it is preferable that the filler contained in the resin layer 5 is dispersed on the insulating part 6 side at the interface between the insulating part 6 and the resin layer 5. Thereby, it can be said that the state where the resin layer 5 and the insulating portion 6 are mixed is formed at the interface between the resin layer 5 and the insulating portion 6, and the adhesion between the resin layer 5 and the insulating portion 6 is improved. It is done. Therefore, the durability of the heating element mounting substrate 50 can be made excellent.

(Insulating part forming resin composition)
Then, the resin composition for insulating part formation is demonstrated.
In the present embodiment, the resin composition forming the insulating portion is set to have a low absolute value of the weight change rate when immersed in an etching solution having a specific composition.

Such a resin composition contains, for example, a thermosetting resin.
The thermosetting resin is not particularly limited. For example, phenol resin, epoxy resin, urea (urea) resin, resin having a triazine ring such as melamine resin, unsaturated polyester resin, bismaleimide (BMI) resin, polyurethane resin , Diallyl phthalate resin, silicone resin, resin having a benzoxazine ring, cyanate ester resin, and the like, and one or more of them can be used in combination.
Among these, an epoxy resin, a phenol resin, and an unsaturated polyester resin are preferable because they have appropriate fluidity and high adhesion to the resin layer 5 and the heat radiation part 7.

  Examples of the phenol resin include unmodified phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, novolak type phenol resin such as arylalkylene type novolak resin, dimethylene ether type resole resin, methylol type resole resin and the like. And resole phenolic resins such as oil-modified resole phenolic resins modified with tung oil, linseed oil, walnut oil and the like.

  Moreover, when using a novolak-type phenol resin, although the hardening | curing agent is contained in the resin composition for insulation part formation, hexamethylenetetramine is normally used as this hardening | curing agent. Furthermore, when hexamethylenetetramine is used, its content is not particularly limited, but it is preferably contained in an amount of 10 to 30 parts by mass, and more preferably 15 to 20 parts by mass with respect to 100 parts by mass of the novolac type phenol resin. It is preferable to contain below part by mass. By setting the content of hexamethylenetetramine in the above range, the cured product of the resin composition for forming an insulating part, that is, the mechanical strength and the amount of molding shrinkage of the insulating part 6 can be improved.

  Among such phenol resins, it is preferable to use a resol type phenol resin. When a novolac type phenol resin is used as a main component, as described above, hexamethylenetetramine is usually used as a curing agent, and corrosive gas such as ammonia gas is generated when the novolac type phenol resin is cured. For this reason, the heat radiation part 7 may corrode due to this, and therefore, a resol type phenol resin is preferably used as compared with a novolac type phenol resin.

  Moreover, a resol type phenol resin and a novolac type phenol resin can be used in combination. Thereby, while being able to raise the intensity | strength of the insulation part 6, toughness can also be improved.

  Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type, bisphenol F type and bisphenol AD type, novolac type epoxy resins such as phenol novolak type and cresol novolak type, brominated bisphenol A type, bromine Brominated epoxy resin such as a fluorinated phenol novolak type, biphenyl type epoxy resin, naphthalene type epoxy resin, tris (hydroxyphenyl) methane type epoxy resin and the like. Among these, bisphenol A type epoxy resins, phenol novolac type epoxy resins, and cresol novolac type epoxy resins having a relatively low molecular weight are preferable. Thereby, workability | operativity at the time of formation of the insulation part 6 and a moldability can be made further favorable. Further, from the viewpoint of heat resistance of the insulating portion 6, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, and a tris (hydroxyphenyl) methane type epoxy resin are preferable, and a tris (hydroxyphenyl) methane type epoxy resin is particularly preferable.

  When using a tris (hydroxyphenyl) methane type epoxy resin, the number average molecular weight is not particularly limited, but is preferably 500 to 2000, and more preferably 700 to 1400.

  Moreover, when using an epoxy resin, it is preferable that a hardening | curing agent is contained in the resin composition for insulation part formation. The curing agent is not particularly limited, and examples thereof include amine compounds such as aliphatic polyamines, aromatic polyamines and diciamine diamide, alicyclic acid anhydrides, acid anhydrides such as aromatic acid anhydrides, and novolak phenols. Examples thereof include polyphenol compounds such as resins, imidazole compounds, and the like. Among these, novolac type phenol resins are preferable. This improves the handling and workability of the insulating portion forming resin composition, and makes the insulating portion forming resin composition excellent in environmental aspects.

  In particular, when a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, or a tris (hydroxyphenyl) methane type epoxy resin is used as the epoxy resin, it is preferable to use a novolac type phenol resin as the curing agent. Thereby, the heat resistance of the hardened | cured material obtained from the resin composition for insulating part formation can be improved. In addition, the addition amount of the curing agent is not particularly limited, but it is preferable that the curing width is within ± 10% by weight from the theoretical equivalent ratio of 1.0 to the epoxy resin.

  Moreover, the resin composition for insulating part formation may contain a hardening accelerator with the said hardening | curing agent as needed. Although it does not specifically limit as a hardening accelerator, For example, an imidazole compound, a tertiary amine compound, an organic phosphorus compound, etc. are mentioned. Although content of a hardening accelerator is not specifically limited, It is preferable that it is 0.1-10 mass parts with respect to 100 mass parts of epoxy resins, and it is more preferable that it is 3-8 mass parts.

In the present embodiment, the content of the thermosetting resin in the insulating part forming resin composition is 10 parts by mass or more with respect to 100 parts by mass of the entire solid content (excluding the solvent) of the insulating part forming resin composition. It is preferable that the amount is 15 parts by mass or more. In addition, the content of the thermosetting resin in the insulating part forming resin composition is 60 parts by mass or less with respect to 100 parts by mass of the entire solid content (excluding the solvent) of the insulating part forming resin composition. Preferably, it is 50 parts by mass or less.
By making content of a thermosetting resin more than a lower limit, the moldability of the insulation part 6 can be made more favorable. Moreover, the insulation of the insulating part 6 can be made more excellent by making content of a thermosetting resin below an upper limit.

  Moreover, it is preferable that the resin composition for insulating part formation contains the fiber reinforcement which functions as a filler. Thereby, the mechanical strength and rigidity of the insulating part 6 itself can be made excellent.

  The fiber reinforcing material is not particularly limited. For example, glass fiber, carbon fiber, aramid fiber (aromatic polyamide), poly-p-phenylenebenzobisoxazole (PBO) fiber, polyvinyl alcohol (PVA) fiber, polyethylene (PE ) Fibers, plastic fibers such as polyimide fibers, inorganic fibers such as basalt fibers, and metal fibers such as stainless steel fibers. One or more of these can be used in combination.

  Further, these fiber reinforcements may be subjected to a surface treatment with a silane coupling agent for the purpose of improving the adhesion with the thermosetting resin. Although it does not specifically limit as a silane coupling agent, For example, an aminosilane coupling agent, an epoxy silane coupling agent, a vinyl silane coupling agent etc. are mentioned, It is used combining these 1 type (s) or 2 or more types. it can.

  Of these fiber reinforcements, glass fibers, carbon fibers, or aramid fibers are preferably used. Thereby, the mechanical strength of the insulating part 6 can further be improved. In particular, the use of carbon fibers can further improve the wear resistance at high loads. In addition, from the viewpoint of further reducing the weight of the insulating portion 6, a plastic fiber such as an aramid fiber is preferable. Furthermore, from the viewpoint of improving the mechanical strength of the insulating portion 6, it is preferable to use a fiber base material such as glass fiber or carbon fiber as the fiber reinforcing material.

The content of the fiber reinforcing material in the insulating part forming resin composition is preferably 30 parts by mass or more with respect to 100 parts by mass of the entire solid content (excluding the solvent) of the insulating part forming resin composition, 35 More preferably, it is at least part by mass. In addition, the content of the fiber reinforcing material in the insulating part forming resin composition is preferably 80 parts by mass or less with respect to 100 parts by mass of the entire solid content (excluding the solvent) of the insulating part forming resin composition. , 60 parts by mass or less is more preferable.
By making the content of the fiber reinforcement more than the lower limit value, the mechanical strength can be improved more reliably. Moreover, the moldability of the insulation part 6 can be made more favorable by making content of a fiber reinforcement below an upper limit.

  Further, the insulating portion forming resin composition may contain a filler other than the fiber reinforcement, and the filler may be either an inorganic filler or an organic filler.

  As the inorganic filler, for example, one or more selected from titanium oxide, zirconium oxide, silica, calcium carbonate, boron carbide, clay, mica, talc, wollastonite, glass beads, milled carbon, graphite and the like are used. . The inorganic filler preferably contains a metal oxide such as titanium oxide, zirconium oxide, or silica. Thereby, the oxide film with which a metal oxide is provided exhibits the function as a passivating film | membrane, and can improve the acid resistance as the whole hardened | cured material.

  As the organic filler, one or more selected from polyvinyl butyral, acrylonitrile butadiene rubber (NBR), pulp, wood powder, and the like are used. The acrylonitrile butadiene rubber may be either partially crosslinked or carboxy modified type. Of these, acrylonitrile butadiene rubber is preferred from the viewpoint of further enhancing the effect of improving the toughness of the cured product.

  In addition to the components described above, additives such as a mold release agent, a curing aid, and a pigment may be added to the insulating portion forming resin composition.

Here, the characteristic with which the resin composition which comprises the insulation part which concerns on this embodiment is provided is demonstrated.
The resin composition for forming an insulating part according to the present embodiment was molded under the following conditions to obtain a test piece. 16.5% by weight of cupric chloride, 25% by weight of hydrogen chloride, 25% by weight of peroxide When immersed in an etching solution containing hydrogen for 1 hour, the absolute value of the weight change rate of the test piece is 0.02% or less.
(Test specimen preparation conditions)
Using a mold having a cavity having a width of 50 mm, a thickness of 3 mm, and a length of 80 mm, the resin composition is molded under conditions of a mold temperature of 170 ° C., a molding pressure of 10 MPa, and a curing time of 180 seconds to obtain a test piece.

When the circuit board 10 described above is manufactured and this circuit board 10 is subjected to a reflow process, there is a concern that the insulating portion 6 and the heat radiating portion 7 may be separated.
Here, the present inventors have found that by satisfying the above-described characteristics, this separation can be efficiently suppressed, and as a result, high reflow resistance as a circuit board can be exhibited.

Here, in this embodiment, the absolute value of the weight change rate of the test piece is preferably 0.018% or less, more preferably 0.015% or less, and further preferably 0.012% or less.
Thus, by setting the absolute value of the weight change rate of the test piece, by setting as described above, the ratio of voids and fragile regions in the insulating portion 6 is controlled. Reflow resistance can be improved.
In addition, the lower limit of the absolute value of the weight change rate of the test piece is not particularly limited, but is, for example, 0.001% or more.

Moreover, about the test piece obtained by the above-mentioned method, it is preferable that the absolute value of the change rate of the glossiness before and behind being immersed in etching liquid is 10% or less.
In the case where the degree of change in glossiness is controlled in this way, an indicator that the insulating portion 6 can sufficiently mitigate the influence when it is affected by the external environment such as a chemical solution condition or a high temperature condition. It becomes.
Therefore, the reflow resistance of the circuit board 10 can be further improved by controlling the absolute value of the change rate of the glossiness.

  In addition, the glossiness in this embodiment shows the value of the measurement angle of 60 degrees measured based on ASTM-D523. The glossiness can be measured using, for example, a digital glossiness meter (20 °, 60 °) (GM-26 type, manufactured by Murakami Color Research Laboratory Co., Ltd.).

Further, the absolute value of the change rate of the glossiness of the test piece is preferably 8% or less, and more preferably 6% or less.
The lower limit value of the change rate of the glossiness of the test piece is not particularly limited, but is, for example, 0.1% or more.

  In addition, in order to satisfy the above characteristics as the resin composition for forming an insulating portion, it is preferable to appropriately select a resin component to be used (more specifically, a thermosetting resin component), and further to appropriately select the content thereof. It can be said that it is a preferable aspect to adjust to.

[Second Embodiment]
Next, a second embodiment in which the heating element mounting substrate is applied to mounting of a semiconductor device will be described.

  FIG. 5 is a longitudinal sectional view showing a second embodiment in which the heating element mounting substrate is applied to mounting of a semiconductor device, and FIG. 6 is a view (plan view) seen from the direction of arrow A in FIG.

  Hereinafter, the heating element mounting substrate 51 of the second embodiment will be described focusing on the differences from the heating element mounting substrate 50 of the first embodiment, and description of similar matters will be omitted.

  A heating element mounting substrate 51 shown in FIG. 5 is shown in FIGS. 1 and 2 except that the semiconductor device 1 is mounted on both the upper surface and the lower surface of a circuit substrate 10 ′ having a configuration different from that of the circuit substrate 10. This is the same as the heating element mounting substrate 50.

  In other words, in the heating element mounting substrate 51 of the second embodiment, the circuit board 10 ′ includes the resin layer 5 and the heat dissipation portion 7 that covers the resin layer 5 corresponding to the first region 15 in a plan view of the resin layer 5. A base material 8 ′ comprising an insulating portion 6 covering the resin layer 5 corresponding to the second region 16, and a resin layer 5 covering the heat radiating portion 7 and the insulating portion 6 with its lower surface, and the base material 8 ′. And a metal layer 4 provided on each of the upper surface and the lower surface. The two semiconductor devices 1 are mounted on the metal layer 4 of the base material 8 ′ in a state where the two semiconductor devices 1 are electrically connected at the connection terminals 12.

  Further, in the base material 8 ′, the heat radiating portion 7 covers the resin layer 5 corresponding to the first region 15 in a plan view of the resin layer 5, and the insulating portion 6 is a second view in the plan view of the resin layer 5. Although the resin layer 5 is covered corresponding to the region 16, in the present embodiment, as shown in FIG. 6, the heat radiation part 7 is exposed on one side surface of the base material 8 ′ (circuit board 10 ′), The heat generated in the two semiconductor devices 1 is radiated from the exposed exposed surface of the heat radiating portion 7.

  The same effect as that of the first embodiment can be obtained by the heating element mounting substrate 51 of the second embodiment.

  The heating element mounting substrate 51 having such a structure is prepared by preparing a metal foil-clad substrate in which the metal foil 4A is provided on both the upper surface and the lower surface of the base material 8 ′, and patterning both the metal foils 4A. After the layer 4 is formed, the semiconductor device 1 is mounted on the metal layer 4.

[Third Embodiment]
Next, a third embodiment in which the heating element mounting substrate is applied to mounting of a semiconductor device will be described.

  FIG. 7 is a longitudinal sectional view showing a third embodiment in which the heating element mounting substrate of the present invention is applied to mounting of a semiconductor device.

  Hereinafter, the heating element mounting substrate 52 of the third embodiment will be described focusing on differences from the heating element mounting substrate 50 of the first embodiment, and description of similar matters will be omitted.

  The heating element mounting substrate 52 shown in FIG. 7 has the same structure as that of FIG. The heating element mounting substrate 50 shown in FIG.

  That is, in the heating element mounting substrate 52 of the third embodiment, the circuit board 10 ″ includes the base material 8 ′ and the metal layer 4 ′ having an opening corresponding to the position where the semiconductor device 1 ′ is mounted. The semiconductor device 1 ′ includes a semiconductor element 17, a bonding wire 18 that electrically connects the semiconductor element 17 and the metal layer 4 ′, and a mold portion 19 that seals the semiconductor element 17 and the bonding wire 18. The semiconductor element 17 is bonded onto the resin layer 5 at the opening of the metal layer 4 ′, and the terminal provided in the semiconductor element 17 and the terminal provided in the metal layer 4 ′ are electrically connected via the bonding wire 18. In a state of being connected to each other, the metal layer 4 ′ is sealed by the mold part 19 on the upper surface side so as to include the opening of the metal layer 4 ′.

  In such a heating element mounting substrate 52, the semiconductor element 17 included in the semiconductor device 1 ′ is bonded to the resin layer 5 included in the base material 8 ′, and the heat generated in the semiconductor element 17 is bonded to the semiconductor element 17. Since the heat is radiated through the resin layer 5 and the heat radiating portion 7, the heat radiation efficiency can be improved.

  The effect similar to that of the first embodiment can be obtained also by the heating element mounting substrate 52 of the third embodiment.

  In FIG. 7, the resin layer 5 is provided in the heat radiating part 7 in the opening of the metal layer 4 ′, and the heat generated in the semiconductor element 17 is transmitted to the heat radiating part 7 through the resin layer 5. However, the present invention is not limited to this, and the formation of the resin layer 5 in the opening of the metal layer 4 ′ is omitted, and the semiconductor element 17 is bonded onto the heat radiating part 7. Alternatively, the heat radiation part 7 may be directly transmitted without passing through the resin layer 5. With this configuration, the heat dissipation efficiency of the heat generated in the semiconductor element 17 can be further improved.

As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to these.
For example, each part which comprises a metal foil tension board | substrate, a circuit board, and a heat generating body mounting board | substrate can be substituted with the thing of the arbitrary structures which can exhibit the same function. Moreover, arbitrary components may be added.
In the present invention, any two or more configurations shown in the first to third embodiments may be combined.
Furthermore, the heating element mounting substrate is not limited to the one described in the above-described embodiment, that is, the heating element is not limited to the one on which the semiconductor device is mounted. , Capacitors, diode power MOSFETs, power transistors such as insulated gate bipolar transistors (IGBTs), reactors, LEDs (light emitting diodes), LDs (laser diodes), light emitting elements such as organic EL elements, motors, etc. Applicable.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to description of these Examples at all.

1. Production of Circuit Board A circuit board was produced as follows.

Example 1
1.1 Preparation of Resin Composition for Forming Resin Layer (Varnish) [1] First, bisphenol F / bisphenol A phenoxy resin (Mitsubishi Chemical, 4275, weight average molecular weight 6.0 × 10 ⁴ , bisphenol F skeleton and bisphenol A Ratio of skeleton = 75: 25) 40.0 parts by mass, bisphenol A type epoxy resin (manufactured by DIC, 850S, epoxy equivalent 190) 55.0 parts by mass, 2-phenylimidazole (2PZ by Shikoku Chemicals) 3.0 parts by mass , 2.0 parts by mass of γ-glycidoxypropyltrimethoxysilane (KBM-403 manufactured by Shin-Etsu Silicone) as a silane coupling agent were weighed, dissolved and mixed in 400 parts by mass of cyclohexanone, and stirred using a high-speed stirring device. Thus, a varnish containing a resin material was obtained.
[2] Next, to the varnish containing the resin material prepared in advance in the step [1], alumina (manufactured by Nippon Light Metal Co., Ltd., average particle size A3.2 μm, primary particle size B3.6 μm, average particle size A / primary A commercially available product (Lot No. Z401) having a particle size B = 0.9 (505.0 parts by mass), using a disperser ("R94077" manufactured by Primics Co., Ltd.), has a rotation speed of 1000 rpm and a stirring time of 120 minutes. The resin composition for resin layer formation of the resin solid content ratio of 83.5 weight% (60.0 volume%) of the alumina was obtained by mixing on these conditions.

1.2 Film Formation of Resin Layer Forming Layer on Metal Foil Using a rolled copper foil having a width of 260 mm and a thickness of 35 μm (manufactured by Nippon Electrolytic Co., Ltd., YGP-35), on the roughened surface of the copper foil, The resin composition for forming a resin layer obtained in 1.1 above is applied with a comma coater and dried by heating at 100 ° C. for 3 minutes and at 150 ° C. for 3 minutes, thereby forming a resin layer having a thickness of 100 μm on the metal foil. A forming layer was formed.

  In addition, by drying the resin composition for forming a resin layer under such conditions, the layer for forming a resin layer is in a semi-cured state. This was cut into a length of 65 mm × width of 100 mm to obtain a metal foil.

1.3 Preparation of Resin Composition for Forming Insulation Part Orthocresol Novolac Type Epoxy Resin (trade name “EOCN-104S” manufactured by Nippon Kayaku Co., Ltd.) 18% by mass, glass fiber (trade name “Nittobo Co., Ltd. CS3E479 ") 35% by mass, silica (manufactured by Denka Co., Ltd., trade name" FB-105 "), 35% by mass, novolac type phenol resin (trade name" PR-51305 ", Sumitomo Bakelite Co., Ltd.) as a curing agent 10 A pulverized product obtained by blending 0.5% by mass of triphenylphosphine as a curing accelerator and 1.5% by mass of other components such as a lubricant, kneading with a heating roll, cooling and pulverizing. By forming a tablet, a resin composition for forming an insulating part having a tablet shape was obtained.

1.4 Formation of Insulating Portion on Resin Layer Regarding the laminate of the metal foil and the semi-cured resin layer forming layer obtained above by preparing the molding die 100 having the structure shown in FIG. An aluminum plate having a thickness of 2 mm was disposed in a partial region of the surface of the resin layer forming layer with the layer forming layer as an upper surface.

  Next, the plunger 112 is inserted into the pot 111 while the resin composition for forming an insulating portion in the pot 111 is heated and melted. Thereby, it fills in a cavity so that the molten resin composition for insulating part formation may cover the layer for resin layer formation in the state heated and pressurized.

  And the circuit board was obtained by hardening the fuse | melted resin composition for insulating part formation, and the layer for resin layer formation.

  The conditions for curing the insulating portion forming resin composition and the resin layer forming layer were set as follows.

・ Heating temperature: 175 ° C
・ Pressure during pressurization: 5.0 MPa
・ Heating / pressurizing time: 3 minutes

2. Manufacture of a test piece About the resin composition for forming an insulating part obtained in 1.3, using a mold having a cavity having a width of 50 mm, a thickness of 3 mm, and a length of 80 mm, a mold temperature of 170 ° C., a molding pressure of 10 MPa, A test piece was obtained by molding under conditions of a curing time of 180 seconds.

(Example 2)
About the resin composition for insulation part formation in said 1.3, phenol aralkyl resin (Mitsui Chemical Co., Ltd. make, brand name "XL-225MB") 30 mass%, hexamethylene tetramine 4 mass%, glass fiber (Nitto Boseki Co., Ltd.) Product name “CS3E479”) 64% by mass, 2% by mass of other components such as a lubricant were blended to obtain the resin composition in the same manner as in Example 1, except that the circuit board and A specimen was obtained.

  The above-mentioned test piece and circuit board are evaluated according to the following.

(Etching solution immersion test)
1. Prepare an etchant containing 16.5 wt% cupric chloride, 25 wt% hydrogen chloride, 25 wt% hydrogen peroxide, The test piece obtained in the item was immersed for 1 hour while shaking.
Table 1 shows the weight of the test piece before and after the immersion test and the weight change rate derived from this weight.

(Glossiness)
About the surface of the test piece before and after the previous etching solution immersion test, using a digital gloss meter (20 °, 60 °) (GM-26 type, manufactured by Murakami Color Research Laboratory Co., Ltd.) according to ASTM-D523. The glossiness at a measurement angle of 60 ° was measured.
Table 1 shows the glossiness of the test piece before and after the immersion test, and the change rate of the glossiness.

(Reflow resistance)
The circuit boards obtained in Examples 1 and 2 and Comparative Example 1 were subjected to a reflow resistance test under the following conditions.
First, the substrate was cut into 5 cm × 8 cm. The substrate was passed once through a reflow apparatus under conditions where the maximum temperature was 260 ° C. and 5 seconds or more and 250 ° C. or more, and then the appearance was confirmed.
This test was evaluated based on the following criteria.
A: There is no blister that can be visually confirmed. B: There are 1 to 5 blisters that can be visually confirmed. X: There are 6 or more blisters that can be visually confirmed.

  As shown in Table 1, in the example, a circuit board exhibiting high reflow resistance could be derived. In addition, as a resin composition for forming an insulating part used in Example 1, when a relatively high hygroscopic calcium silicate filler is used instead of silica, the weight change before and after the etchant immersion test occurs. As a result, the reflow resistance test was inferior to the other examples.

DESCRIPTION OF SYMBOLS 1, 1 'Semiconductor device 4, 4' Metal layer 4A Metal foil 5 Resin layer 5A Resin layer formation layer 6 Insulation part 7 Radiating part 8, 8 'Base material 10, 10', 10 "Circuit board 10A Metal foil tension board DESCRIPTION OF SYMBOLS 11, 19 Mold part 12 Connection terminal 15 1st area | region 16 2nd area | region 17 Semiconductor element 18 Bonding wire 50, 51, 52 Heating body mounting substrate 100 Molding die 110 Upper mold 111 Pot 112 Plunger 113 Supply path 120 Below Mold 121 Cavity 130 Insulating part forming resin composition

Claims (14)

A circuit board in which a composite layer including an insulating portion and a heat radiating portion, a resin layer and a metal layer are laminated in this order, is a resin composition constituting the insulating portion,
The resin composition was molded under the following conditions to obtain a test piece, which was immersed in an etching solution containing 16.5% by weight cupric chloride, 25% by weight hydrogen chloride, and 25% by weight hydrogen peroxide for 1 hour. A resin composition in which the absolute value of the weight change rate of the test piece is 0.02% or less when the test piece is made.
(Test specimen preparation conditions)
Using a mold having a cavity having a width of 50 mm, a thickness of 3 mm, and a length of 80 mm, the resin composition is molded under conditions of a mold temperature of 170 ° C., a molding pressure of 10 MPa, and a curing time of 180 seconds to obtain a test piece. The resin composition according to claim 1,
The said resin composition is a resin composition containing 1 or more types of thermosetting resins chosen from the group which consists of an epoxy resin, a phenol resin, and unsaturated polyester resin. The resin composition according to claim 2,
Content of the said thermosetting resin is a resin composition which is 10 to 60 mass parts with respect to 100 mass parts of the whole solid content of the said resin composition. The resin composition according to any one of claims 1 to 3,
Furthermore, the resin composition containing a fiber reinforcement. The resin composition according to claim 4,
Content of the said fiber reinforcement is a resin composition which is 30 to 80 mass parts with respect to 100 mass parts of the whole solid content of the said resin composition. A resin composition according to any one of claims 1 to 5,
The resin composition whose absolute value of the change rate of the glossiness before and behind immersing the said test piece in etching liquid is 10% or less.   A circuit board comprising a composite layer comprising an insulating part obtained by curing the resin composition according to claim 1 and a heat radiating part, a resin layer, and a metal layer laminated in this order.   A heating element mounting board comprising the circuit board according to claim 7 and a heating element. A method of manufacturing a circuit board in which a composite layer including an insulating portion and a heat dissipation portion, a resin layer, and a metal layer are laminated in this order,
The manufacturing method is
Preparing a laminate of the metal layer and the resin layer;
Disposing the heat dissipating part on a part of the surface of the laminate on the resin layer side;
Forming the insulating part with a resin composition in a region where the heat dissipating part is not disposed on the surface of the laminate on the resin layer side;
Including
The resin composition was molded under the following conditions to obtain a test piece, which was immersed in an etching solution containing 16.5% by weight cupric chloride, 25% by weight hydrogen chloride and 25% by weight hydrogen peroxide for 1 hour. A method of manufacturing a circuit board, wherein the absolute value of the rate of change in weight of the test piece is 0.02% or less.
(Test specimen preparation conditions)
Using a mold having a cavity having a width of 50 mm, a thickness of 3 mm, and a length of 80 mm, the resin composition is molded under conditions of a mold temperature of 170 ° C., a molding pressure of 10 MPa, and a curing time of 180 seconds to obtain a test piece. A circuit board manufacturing method according to claim 9,
The said resin composition is a manufacturing method of a circuit board containing 1 or more types of thermosetting resins chosen from the group which consists of an epoxy resin, a phenol resin, and unsaturated polyester resin. It is a manufacturing method of the circuit board according to claim 10,
Content of the said thermosetting resin is a manufacturing method of a circuit board which is 10 to 60 mass parts with respect to 100 mass parts of the whole solid content of the said resin composition. A method of manufacturing a circuit board according to any one of claims 9 to 11,
The method for producing a circuit board, wherein the resin composition further includes a fiber reinforcing material. It is a manufacturing method of the circuit board according to claim 12,
Content of the said fiber reinforcement is a manufacturing method of a circuit board which is 30 to 80 mass parts with respect to 100 mass parts of the whole solid content of the said resin composition. A method for manufacturing a circuit board according to any one of claims 9 to 13,
A method for manufacturing a circuit board, wherein an absolute value of a change rate of gloss before and after immersing the test piece in an etching solution is 10% or less.

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