JP2020127024A - Wiring board and electronic apparatus - Google Patents

Abstract

To provide a wiring board that prevents disconnection of a side conductor on an inside surface of a castellation.SOLUTION: A wiring board 202 has an insulating substrate that includes a first insulating layer 101b and a second insulating layer 101a, a first castellation that is formed from a first principal surface 103 to a side face, and a side conductor 109 that is adhered to an inside surface of the first castellation. At least a portion of the inside surface of the first castellation to which the side conductor 109 is adhered becomes narrower from an end facing a second principal surface 104 toward an end facing the first principal surface 103, and the second insulating layer 101a is located on the end facing the second principal surface 104 of the side conductor 109. The insulating substrate has a second castellation on the second principal surface 104, and the width thereof facing the second principal surface 104 is larger than the width thereof facing the first principal surface 103.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wiring board and an electronic device.

Conventionally, a wiring board used for mounting electronic components such as semiconductor elements and surface acoustic wave elements is an insulating substrate made of a ceramic sintered body such as an aluminum oxide sintered body or a glass ceramic sintered body. It has a mounting part for mounting. After the electronic component is mounted on the mounting portion, the lid is joined to the insulating substrate to hermetically seal the mounting portion.

Such a wiring board is generally manufactured in the form of a so-called multi-cavity wiring board in which a plurality of wiring boards are simultaneously and collectively obtained from one large-area mother board. In the multi-cavity wiring board, a plurality of wiring board regions are arranged vertically and horizontally on a mother board made of, for example, an aluminum oxide sintered body. Dividing grooves are formed on the main surface such as the upper surface of the mother board along the boundary of the wiring board region. A bending stress is applied to the mother board across the dividing groove to break the mother board, whereby the mother board is divided into individual wiring boards. The dividing grooves are formed, for example, by making a notch on the upper surface and the lower surface of the unbaked mother substrate along the outer periphery of the wiring substrate region with a predetermined depth using a cutter blade or the like (see Patent Document 1). ..

Through holes are provided at the boundaries of the wiring board regions, and conductor layers (side surface conductors) for electrically connecting the respective wiring conductors to each other are provided on the inner side surfaces of the through holes between the adjacent wiring board regions. It is provided. The side surface conductors electrically connect the wiring conductors in the plurality of wiring board regions to each other. Thereby, for example, the wiring conductors in a plurality of wiring board regions can be integrated and subjected to electrolytic plating for protection or the like.

In recent years, wiring boards have become smaller, and for example, one having a size of 1.6×1.2 mm in length and width is manufactured. Along with the miniaturization of this wiring board, the wiring board area in the multi-cavity wiring board is also becoming smaller. In such a multi-cavity wiring board in which wiring board areas that are remarkably miniaturized are arranged, a cutter blade is placed at the boundary between adjacent wiring board areas in an unfired state due to reasons such as the accuracy of mechanical processing. It is difficult to provide a dividing groove by using it. Therefore, a method has been proposed in which the dividing groove is formed by laser processing with excellent positional accuracy (see Patent Document 2).

JP 2006-5035 JP JP 2012-81647 JP

However, the following problems may occur in the conventional multi-cavity wiring board. That is, when the dividing groove is formed at the boundary of each wiring board region of the mother board by laser processing, there is a possibility that a part of the side surface conductor in this through hole is cut. In this case, for example, when electrolytic plating is performed after forming the groove, there is a possibility that a plating layer is not deposited on the wiring conductor in at least a part of the plurality of wiring board regions.

A wiring board according to one aspect of the present invention includes an insulating substrate including a first insulating layer having a first main surface and a second insulating layer having a second main surface opposite to the first main surface; A first castellation formed from a surface to a side surface; and a side surface conductor attached to an inner side surface of the first castellation, wherein the side surface conductor is provided on at least the inner side surface of the first castellation. The portion to which is adhered is narrowed inward from the end portion on the second main surface side to the end portion on the first main surface side, and the second insulating layer is the second main surface of the side surface conductor. Is located on an end on the side, the insulating substrate has a second castellation on the second major surface, the second castellation being in communication with the first castellation, and The width on the second main surface side is larger than the width on the first main surface side. Also, an insulating substrate including a first insulating layer having a first main surface and a second insulating layer having a second main surface facing the first main surface, and a first substrate formed from the first main surface to the side surface. A castellation and a side surface conductor attached to the inner side surface of the first castellation, and a portion of the first castellation where the side surface conductor is attached to at least the inner side surface is The second insulating layer is narrowed inward from the end portion on the second main surface side to the end portion on the first main surface side, and the second insulating layer is located on the end portion on the second main surface side in the side surface conductor. The side conductor is thicker at the end on the second main surface side than at the end on the first main surface side.

An electronic device according to one aspect of the present invention includes the wiring board having the above-described configuration and an electronic component mounted on the wiring board.

According to the wiring board of one aspect of the present invention, it is possible to provide a wiring board in which disconnection of the side surface conductor is suppressed. That is, the structure is such that the first castellation is narrowed inward from the end on the second main surface side to the end on the first main surface side. In other words, when viewed from the first main surface side, the side surface conductor in the first hole is hidden behind the first main surface side of the mother substrate and is difficult to see. Therefore, when the split groove is formed across the hole for castellation formed at the boundary of each wiring board region of the mother board by laser processing, it is difficult for the side surface conductor in the first hole portion to be irradiated with laser, and thus the side surface conductor. Is prevented.

According to the electronic device of one aspect of the present invention, it is possible to provide the electronic device in which the disconnection of the side surface conductor is suppressed because the electronic device has the wiring board having the above configuration.

(A) is a top view which shows the principal part in the multi-cavity wiring board containing the wiring board of embodiment of this invention, (b) is sectional drawing in the X-X' line of (a). (A) is a top view which shows the wiring board of embodiment of this invention, (b) is the bottom view. FIG. 2 is a cross-sectional view showing further enlarged main parts of a multi-cavity wiring board including the wiring board shown in FIG. 1. It is sectional drawing which expanded the principal part which shows the multi-cavity wiring board containing the wiring board of other embodiment of this invention. (A)-(e) is sectional drawing which shows the manufacturing method of the multi-cavity wiring board containing the wiring board of embodiment of this invention.

A wiring board and an electronic device of the present invention will be described with reference to the accompanying drawings.

1A is a top view showing a main part of a multi-cavity wiring board including a wiring board according to an embodiment of the present invention, and FIG. 1B is a line XX′ of FIG. 1A. FIG. 2 is a top view showing a wiring board according to an embodiment of the present invention, and FIG. 2(b) is a bottom view thereof. Further, FIG. 3 is a cross-sectional view further enlarging a main part of a multi-cavity wiring board including the wiring board shown in FIG. 4(a) is an enlarged cross-sectional view showing a main part of a first modified example of a multi-cavity wiring board including the wiring board shown in FIG. 1, and FIG. 4(b) is a bottom view thereof. Is. The multi-cavity wiring board of the embodiment may be a multi-cavity wiring board in which a larger number of parts as shown in FIG. 1 are connected.

In the multi-cavity wiring board of the embodiment, a plurality of wiring board regions 102 are arranged on a mother board 101. The mother substrate 101 has a first main surface 103 and a second main surface 104. A dividing groove 106 is provided along the boundary 105 of the wiring board region 102. In the portion where the dividing groove 106 is provided, the mother substrate 101 has a through hole (no reference numeral). The through hole has a first hole portion 107 and a second hole portion 108. A side surface conductor 109 is provided on the inner side surface of the first hole portion 107. In each wiring board region 102, a concave mounting portion 110 for housing an electronic component is provided on the upper surface of the mother board 101. A connection conductor 111 is provided on the bottom surface of the mounting portion 110. Further, the multi-cavity wiring board has an auxiliary conductor 112, a wiring conductor 113, a frame-shaped metallized layer 114, an external connection conductor 115 and the like as other conductor portions. Further, each mounting portion 110 of the multi-cavity wiring board is sealed with a sealing material such as a lid. The mother substrate 101 includes an upper insulating layer 101a and a lower insulating layer 101b stacked under the upper insulating layer 101a. The upper insulating layer 101a has a plurality of penetrating portions (no reference numeral) to be the mounting portion 110. The lower insulating layer 101b has a flat plate shape.

A portion of the upper surface of the lower insulating layer 101b, which is exposed inside the through portion of the upper insulating layer 101a, corresponds to the bottom surface of the mounting portion 110. The penetrating portion of the upper insulating layer 101 a corresponds to the side wall portion surrounding the mounting portion 110. The wiring board region 102 is divided into individual wiring boards 202, which will be described later. Each of the individual wiring boards 202 has a concave mounting portion 110 at the center of the upper surface. The frame portion surrounding the mounting portion 110 is formed by dividing the frame-shaped portion surrounding the through portion of the upper insulating layer 101a into individual pieces.

As described above, the mother board 101 is divided along the boundary 105 of the wiring board region 102, and the individual wiring board 202 as shown in FIG. 2, for example, is manufactured. The individual wiring board 202 to be produced is such that the frame-shaped metallized layer 114 and the wiring conductor 113 are formed on an insulating substrate (no reference numeral) in which a frame-shaped upper insulating layer 101a is laminated on the upper surface of the lower insulating layer 101b. It is provided and basically configured. Electronic components are mounted in the mounting portion 110 of the wiring board 202 to manufacture an electronic device (not shown). In the following description of the individual wiring board 202, the same parts as those of the multi-piece wiring board are denoted by the same reference numerals without particularly distinguishing them.

The mother substrate 101 is, for example, a ceramic sintered body such as an aluminum oxide sintered body, a glass ceramic sintered body, an aluminum nitride sintered body, a silicon carbide sintered body, a silicon nitride sintered body or a mullite sintered body. It is formed by a united body.

In the example of this embodiment, as shown in FIG. 1 and the like, a discard margin region is provided on the outer periphery of the mother substrate 101 so as to surround a plurality of arranged wiring substrate regions 102 (not shown). The discarding margin area is provided for facilitating the handling of the multi-cavity wiring board. Further, for example, terminals for plating (not shown) are provided on opposite sides of the discarding margin area in order to deposit electrolytic plating on the wiring conductors 113 and the like in each wiring board area 102.

The mother substrate 101 is manufactured, for example, by integrally firing the upper insulating layer 101a and the lower insulating layer 101b. That is, by adding an appropriate organic solvent and a binder to a raw material powder containing a glass component such as aluminum oxide and silicon oxide, a plurality of ceramic green sheets are produced by forming into a sheet shape, and a part of this is punched. After forming a plurality of through-holes, the ceramic green sheet with through-holes is laminated on a flat ceramic green sheet that has not been punched, and the laminated body is integrally fired, The mother substrate 101 in which the insulating layer 101a and the lower insulating layer 101b are stacked can be manufactured.

As described above, the plurality of wiring board regions 102 arranged on the mother board 101 are provided with concave mounting of electronic components (not shown) in the central portion or the like on the second main surface 104 (upper surface in this embodiment). Part 110
have. In each wiring board region 102, for example, an electronic component is mounted and fixed on the upper surface of the lower insulating layer 101b exposed in the mounting portion 110. Further, this electronic component is protected by the frame-shaped portion of the upper insulating layer 101a surrounding the mounting portion 110 (the penetrating portion of the upper insulating layer 101a).

Also in the wiring board 202 formed by dividing the wiring board region 102 into individual pieces, the lower insulating layer 101 is formed.
The electronic component is mounted on b and is housed in the mounting portion 110 and protected by the frame-shaped upper insulating layer 101a. The wiring board 202 has castellations 118 as marks of the hole portions at the corners.

The electronic components accommodated in the mounting portion 110 include various types of piezoelectric vibrators such as a crystal resonator, surface acoustic wave elements, semiconductor elements such as semiconductor integrated circuit elements (ICs), capacitive elements, inductor elements and resistors. Electronic components can be mentioned.

A wiring conductor 113 is formed inside and on the surface of the mother board 101 from the bottom of the mounting portion 110 to the lower surface of the mother board 101. The portion of the wiring conductor 113 formed at the bottom of the mounting portion 110 is directly connected to, for example, the connection conductor 111 provided at the end of the mounting portion 110 on the short side. The portion of the wiring conductor 113 formed on the lower surface of the mother board 101 is directly connected to, for example, the external connection conductor 115 located on the outer peripheral portion of the lower surface of each wiring board region 102. The external connection conductor 115 functions as a connection pad for electrically connecting, for example, the individual wiring board 202 (electronic device) to an external electric circuit (not shown). Among the wiring conductors 113, those formed inside the mother board 101 (not shown) are in the form of so-called via conductors or internal wiring layers. By electrically connecting the electronic component mounted on the mounting portion 110 to the wiring conductor 113 via the connection conductor 111, the electronic component is externally connected via the connection conductor 111, the wiring conductor 113, the external connection conductor 115, and the like. Is electrically connected to the electric circuit of.

The conductor portion such as the wiring conductor 113 is, for example, copper, silver, palladium, gold, platinum, tungsten,
It is made of a metal material such as molybdenum or manganese. If the wiring conductor 113 and the like are made of, for example, molybdenum, a metal paste (not shown) prepared by adding an organic solvent and a binder to molybdenum powder is formed into a predetermined pattern on the ceramic green sheet serving as the mother substrate 101. It can be formed by applying and baking it simultaneously.

The wiring board 202 manufactured by dividing the multi-cavity wiring board of such a form into individual pieces,
For example, a piezoelectric vibrating element is mounted as an electronic component, and is used as an oscillator serving as a frequency or time reference in electronic devices such as communication devices such as mobile phones and car phones, and information devices such as computers and IC cards.

As described above, in order to divide the mother board 101, the division grooves 106 are formed on the first main surface 103 and the second main surface 104 of the mother board 101 along the outer periphery of the wiring board region 102. By applying stress to the mother substrate 101 at the portion where the dividing groove 106 is formed (boundary 105 of the wiring substrate region 102) and breaking the mother substrate 101 in the thickness direction, the multi-cavity wiring substrate is an individual wiring substrate. Divided into 202.

The dividing groove 106 is, for example, a groove processed by laser light (hereinafter, also simply referred to as laser processing) along the outer periphery of the wiring board region 102 with respect to the first main surface 103 and the second main surface 104 of the mother substrate 101. It is applied and formed.

In the example of this embodiment, a frame-shaped metallized layer 114 is formed on the upper surface of each wiring board region 102 in contact with the division groove 106. The lid is joined to the frame-shaped metallized layer 114 to seal the mounting portion 110. Further, plating layers (not shown) such as a nickel plating layer and a gold plating layer are sequentially deposited on the frame-shaped metallized layer 114. The frame-shaped metallized layer 114 is made of, for example, the same metal material as the wiring conductor 113 and the like. For example, when the frame-shaped metallized layer 114 is formed of a molybdenum metallized layer, a metal paste prepared by adding an organic solvent, a binder or the like to molybdenum powder is used as a ceramic green layer (the frame portion). It can be formed by printing a predetermined pattern on the upper surface of the sheet. The metal paste is formed, for example, so that the thickness of the frame-shaped metallized layer 114 after firing is about 5 to 20 μm.

Further, the plating layer of nickel or the like covering the frame-shaped metallized layer 114 is formed to prevent oxidative corrosion of the frame-shaped metallized layer 114 and to improve wettability and bonding strength during brazing and the like. Is. The plating layer preferably has a two-layer structure in which, for example, a nickel plating layer is formed on the lower side and a gold plating layer is formed on the upper side. Here, from the viewpoint of cost, it is preferable that the metal plating film is thinly formed, and the nickel plating layer is formed to have a thickness of about 1 to 20 μm and the gold plating layer is formed to have a thickness of about 0.1 to 1.0 μm. These metal plating films can be formed, for example, by supplying an electric current for plating to a plated portion (exposed surface of the frame-shaped metallized layer 114) in a plating solution to perform electroplating.

The mother substrate 101 has a hole (no reference numeral) penetrating in the thickness direction of the mother substrate 101 in a portion where the dividing groove 106 is provided. The hole portion includes a first hole portion 107 and a second hole portion 108. Of these, the side surface conductor 109 is attached to the inner peripheral surface of the first hole portion 107 formed upward from the first main surface 103. The side surface conductor 109 is, for example, a metallized layer made of the same metal material as the wiring conductor 113 and the like. The side surface conductor 109 acts as a conduction path for electrically connecting the conductor portions such as the wiring conductors 113 between the adjacent wiring board regions 102 to each other. The side surface conductors 109 electrically connect the conductor portions of the plurality of wiring board regions 102 to each other. As a result, for example, the conductor portions of the plurality of wiring board regions 102 are integrally and electrically connected to each other, and the exposed portions (the connection conductor 111, the external connection conductor 115, and the like) are collectively plated with nickel or the like. Layers can be applied. The side conductor 109 is
This is a portion where terminals for external connection and the like are provided in the individual wiring board 202.

In the example of this embodiment, the portion of the first hole portion 107 where the side surface conductor 109 is attached to the inner side surface is inward from the end portion on the second main surface 104 side to the end portion on the first main surface 103 side. It is narrowing.

That is, for example, the inner diameter of the first hole portion 107, which is circular when viewed from the first main surface 103 side, narrows inward from the end portion on the second main surface 104 side to the end portion on the first main surface 103 side. It has a structure. In other words, when viewed from the first main surface 103 side, the side surface conductor 109 in the first hole portion 107 is hidden by the first main surface 103 side of the mother substrate 101 to make it difficult to see. Therefore, when the dividing groove 106 is formed in the boundary 105 of each wiring substrate region 102 of the mother substrate 101 by laser processing, a laser beam (hereinafter, simply referred to as a laser) 119 is applied to the side surface conductor 109 in the first hole portion 107. It is difficult to irradiate and the disconnection of the side surface conductor 109 is suppressed. This state will be described in detail below with reference to FIG.

The holes formed at the boundaries 105 of the respective wiring board regions 102 of the mother substrate 101 are the first holes 107 formed on the first main surface 103 side and the second holes formed on the second main surface 104 side. And 108 are formed so as to communicate with each other in the thickness direction of the mother substrate 101. When the dividing groove 106 is formed on the boundary 105 of the mother substrate 101 by the laser 119, the laser 119 is continuously irradiated along the diameter of the hole. The dividing groove 106 formed by the laser 119 is formed on both the first main surface 103 side and the second main surface 104 side. Since the side surface conductor 109 is attached to the inner side surface of the first hole portion 107, if the side surface conductor 109 is also irradiated with the laser 119, the side surface conductor 109 may be scraped. In this case, the side conductor 109 may be broken or the conduction resistance may increase. That is, the conductivity of the current for electroplating may be reduced between the adjacent wiring conductors 113.

On the other hand, for example, as shown in FIG. 3, the inner diameter of the first hole 107 is narrowed inward from the end on the second main surface 104 side to the end on the first main surface 103 side. The first main surface 103 side of the mother substrate 101 acts as a shield for the laser 119. Thereby, irradiation of the laser 119 to the side surface conductor 109 can be suppressed. Therefore, disconnection of the side surface conductor 109 and increase in conduction resistance are suppressed. In the processing of the dividing groove 106 by the laser 119 near the hole, the depth of the dividing groove 106 is slightly increased by continuously irradiating the inner surface of the hole with the laser 119 as shown by the broken line in FIG. Tends to deepen.

As described above, the side surface conductor 109 acts as a conduction path for electrically connecting the wiring conductors 113 to each other between the adjacent wiring board regions 102. Therefore, if the dividing groove 106 is too deep, the side surface conductor 109 may be scraped by the dividing groove 106, and the conductivity between the adjacent wiring conductors 113 may be reduced. Therefore, the dividing groove 106 is formed with a depth of about 30 to 70% with respect to the thickness direction of the side surface conductor 109. Further, the conduction between the side surface conductor 109 and the connection conductor 111 of the mounting portion 110 is ensured by, for example, the wiring conductor 113 formed between the upper insulating layer 101a and the lower insulating layer 101b.
Done by. In this case, the side surface conductor 109 and the connection conductor 111 are connected via the wiring conductor 113.

In this embodiment, the dividing groove 106 is formed by the laser 119 on the second main surface 104 side as well as on the first main surface 103 side. When the wiring conductor serving as the conductive path for plating is not formed on the second main surface 104 side, the restriction on the depth of the dividing groove 106 is reduced due to deterioration of conductivity, disconnection, or the like. That is, for example, the dividing groove 106 deeper than the first main surface 103 side has the second main surface 104.
It may be provided on the side to facilitate breakage of the mother substrate 101.

Further, when the mother substrate 101 has the second hole portion 108 on the second main surface 104, the second hole portion 108 communicates with the first hole portion 107 and at the side of the second main surface 104 side. The opening may be larger than the opening on the first main surface 103 side. Also in this case, when the dividing groove 106 is formed by the laser 119 on the first main surface 103 side (the region of the lower insulating layer 101b), the side surface conductor 109 in the first hole 107 is less likely to be irradiated with the laser 119, The disconnection of the side surface conductor 109 is suppressed. Further, when the dividing groove 106 is formed by the laser 119 on the second main surface 104 side (the region of the upper insulating layer 101a), the laser 119 is likely to be irradiated to the depth of the second hole 108. Therefore, the dividing groove 106 can be formed sufficiently deep even in the portion where the second hole portion 108 is located. Therefore, it is possible to provide a more advantageous form for improving the dividing property of the mother substrate 101.

This will be described in more detail. When the dividing groove 106 is formed in the first and second main surfaces 103, 104 (hereinafter, also simply referred to as both main surfaces) of the mother substrate 101, the dividing groove 106 on the first main surface 103 side is seen in plan view. Since the dividing grooves 106 on the second main surface 104 side are formed at substantially the same positions as each other, when the mother substrate 101 is broken in the thickness direction, breakage easily occurs between the upper and lower dividing grooves 106. This makes it possible to manufacture the wiring board 202 in which burrs and chips are suppressed on the side surface (broken surface) after the mother board 101 is divided. Therefore, considering the easiness of breaking of the mother substrate 101, it is preferable that the upper and lower dividing grooves 106 are formed so as to overlap each other at the same position in plan perspective, and the dividing grooves 106 are formed at such positions. Laser processing etc. are performed.

However, the dividing groove 106 is formed by the laser 119 at the boundary 105 of the wiring board region 102 of the mother board 101.
If the first hole portion 107 and the second hole portion 108 communicate with each other with the same diameter as described above, the side surface conductor 109 may be irradiated with the laser 119 twice. That is, a laser 119 for forming the dividing groove 106 on the second main surface 104 side and a laser 119 for forming the dividing groove 106 on the first main surface 103 side. At this time, the holes (on the virtual extension line of the dividing groove 106) are overlapped and irradiated, and the side surface conductor 109 is more likely to be scraped by the laser 119. Therefore, there is a possibility that the disconnection or the decrease in conductivity as described above increases.

On the other hand, when the opening on the second main surface 104 side is larger than the opening on the first main surface 103 side in the second hole portion 108 as in the example of FIG. 3, the side surface is on the first main surface 103 side. The side surface of the second hole portion 108 can be seen through from the top view on the second main surface 104 side while suppressing the disconnection of the conductor 109 and the decrease in conductivity. That is, since the laser 119 is likely to be irradiated deep inside the second hole 108, the dividing groove 106 formed near the second hole 108 on the second main surface 104 side is formed deeper. Therefore, the dividing property of the mother substrate 101 is improved.

Further, in this case, since the opening of the second hole portion 108 on the first main surface 103 side is small, the second hole portion 108 is small.
The inner side surface of the first hole 107 acts as a shielding region of the laser 119 with respect to the side surface conductor 109 on the inner side surface of the first hole 107. Therefore, the side surface conductor 109 is less likely to be irradiated with the laser 119 from the second main surface 104 side. Therefore, there is less possibility that the laser 119 will break the side conductor 109 or reduce the conductivity.

Further, in this case, the following effects are also obtained. That is, in the second hole portion 108, the opening on the second main surface 104 side is larger than the opening on the first main surface 103 side, and the dividing groove 106 is formed relatively deeply from the second main surface 104 side. The circulation of the liquid into the holes (the first holes 107 and the second holes 108) is improved, and the dischargeability of bubbles (hydrogen gas) and the like generated during plating to the outside of the holes is improved. Therefore, it is possible to prevent the plating layer from being chipped or becoming thinner than a predetermined plating thickness, and the side surface conductor 109 can be properly coated with the plating layer.

The side surface conductor 109 may be thicker at the end portion on the second main surface 104 side than at the end portion on the first main surface 103 side. Even in such a case, when the dividing groove 106 is formed with the laser 119 on the first main surface 103 side (the region of the lower insulating layer 101b), the side surface conductor 109 in the first hole 107 is irradiated with the laser 119. Hateful. Further, since the thickness of the side surface conductor 109 is large at the end portion on the side of the second main surface 104, it becomes a structure in which a cross-sectional area (a cross-sectional area in a direction orthogonal to a current transmitted through the conductor) as a conductor can be easily secured. Therefore, the disconnection of the side surface conductor 109 and the decrease in conductivity are suppressed more effectively. In the following description, the cross section as the conductor is simply referred to as a cross section.

This example is shown in the cross-sectional view of the main part of FIG. In FIG. 3, the thickness of the side surface conductor 109 is thicker at the end portion on the second main surface 104 side, and the cross-sectional area as a conductor on the inner side of the first hole portion 107 (that is, the second main surface 104 side) is larger. It's getting bigger. Further, in this example, the inner side surface of the first hole portion 107 to which the side surface conductor 109 is attached is inclined inward from the end portion on the second main surface 104 side to the end portion on the first main surface 103 side. .. That is, the end portion of the second main surface 104 of the side surface conductor 109 is thickened without protruding to the inside of the first hole portion 107. When the dividing groove 106 is formed by the laser 119 in this state, deterioration of the conductivity of the side surface conductor 109, disconnection, etc. can be suppressed more effectively.

When the dividing grooves 106 are formed on both main surfaces of the mother substrate 101, the second groove is formed in the same manner as the first main surface 103 side.
The dividing groove 106 formed by the laser 119 is also formed on the main surface 104 side. Since the opening of the second hole portion 108 on the side of the second main surface 104 is larger than the opening on the side of the first main surface 103, the side surface conductor 109 includes not only the laser 119 on the side of the first main surface 103 but also the second main surface. The laser 119 on the 104 side may be overlapped and irradiated on the extension line of the dividing groove 106. However, since the thickness of the side surface conductor 109 is large at the end portion on the second main surface 104 side, the possibility of disconnection of the side surface conductor 109 or deterioration of conductivity is reduced.

Further, FIG. 4 shows a structure in which no hole is formed in the second main surface 104 of the mother substrate 101, that is, the hole (first hole 107) has no opening on the second main surface 104 side. ing. Also in the example of FIG. 4, the thickness of the side surface conductor 109 is thick at the end portion on the second main surface 104 side. Even in such a case, the cross-sectional area as a conductor becomes large on the back side of the first hole portion 107 (that is, the second main surface 104 side), so that the conductivity of the side surface conductor 109 is reduced, the disconnection or the like is more effectively performed. Is suppressed.

In the structure shown in FIG. 4, when the dividing grooves 106 are formed on both main surfaces of the mother substrate 101, the dividing grooves 106 by the laser 119 are formed on the second main surface 104 side similarly to the first main surface 103 side. However, since the holes are not opened on the second main surface 104 side, the upper insulating layer 101a serves as a shield region for the laser 119, and the side surface conductor 109 is formed with the dividing groove 106 on the second main surface 104 side. The laser 119 does not overlap the side surface conductor 109 (from above and below). Therefore, the decrease in the conductivity of the side surface conductor 109, the disconnection, and the like are further effectively suppressed.

Further, in this example, the dividing groove 106 on the first main surface 103 side and the dividing groove 106 on the second main surface 104 side may communicate with each other above the first hole portion 107 (not shown). In this example, since no hole exists on the second main surface 104 side, the laser 119 on the first main surface 103 side irradiates the upper insulating layer 101a exposed at the bottom of the first hole 107. As a result, the division groove 106 is also formed in the hole portion on the side of the first main surface 103 of the upper insulating layer 101a (bottom portion of the hole portion). At this time, when the laser 119 is irradiated to the second main surface 104 side along the boundary 105 of the wiring board region 102, the bottom of the dividing groove 106 on the second main surface 104 side and the first main surface 103 side. The bottom of the dividing groove 106 communicates with each other at the hole.

In this case, the depth of the dividing groove 106 formed by the laser 119 on the second main surface 104 side does not exceed the thickness of the upper insulating layer 101a in the region other than the hole. Therefore, there is little possibility that the wiring conductor 113 or the side surface conductor 109 will be broken by the dividing groove 106 or a part of the cross-section will be cut to lower the conductivity. Also in this case, the communication of the divided grooves 106 improves the circulation of the plating solution to the first holes 107, so that the side surface conductor 109 can be satisfactorily coated with the plating layer.

The shape and depth of the dividing groove 106 may be, for example, the thickness relationship (thickness ratio) between the upper insulating layer 101a and the lower insulating layer 101b, the position of the wiring conductor 113, the type of laser, the intensity (output of the laser processing apparatus). ), etc., and can be set variously. As the type of laser, for example, one having a wavelength in the ultraviolet region can be used. A laser having a wavelength in the ultraviolet region has a pulse frequency of 10 to 200 kHz by a solid laser, a pulse width of 5 ns or more, and a processing point output of about 1 to 40 W. Some solid-state lasers having a wavelength in the ultraviolet region are excited by crystals such as YAG and YVO _4, and the optimum one may be selected according to their pulse characteristics and the workability of the workpiece.

Further, the mother board 101 may have an auxiliary conductor 112 therein. The auxiliary conductor 112 is, for example, an internal conductor for connecting the end portion (upper end portion) of the side surface conductor 109 on the second main surface 104 side and the wiring conductor 113 to each other. The auxiliary conductor 112 includes, for example, the upper insulating layer 101a and the lower insulating layer 101b at the interface between the upper insulating layer 101a and the lower insulating layer 101b in order to improve the electrical connection reliability between the side surface conductor 109 and the wiring conductor 113. It may be provided on both surfaces (this state is not shown).

In addition, when the auxiliary conductor 112 is provided, the upper end portion of the side surface conductor 109 is made relatively thick to surround the first hole portion 107 in a plan view at the interface portion between the upper insulating layer 101a and the lower insulating layer 101b. The side conductor 109 may have a relatively large width. In this case, since the side conductor 109 and the auxiliary conductor 112 are connected in a wider range, the side conductor 109 and the auxiliary conductor 112 of the upper insulating layer 101a can be connected to each other without forming the auxiliary conductor 112 on the lower insulating layer 101b. Can be connected well.

When the upper end of the side surface conductor 109 is relatively thick, a part of the upper end of the side surface conductor 109 is deformed to form a protruding portion 117 protruding toward the second hole 108 (upward) as shown in FIG. May be done. Since the protruding portion 117 overlaps the auxiliary conductor 112 formed on the upper insulating layer 101a on the inner side surface of the hole (exposed surface of the mother substrate 101), the side conductor 109 and the auxiliary conductor 112 of the wiring conductor 113 are further overlapped.
The electrical connection via the can be ensured. In order to effectively form the protruding portion 117 of the side surface conductor 109, the diameter of the first hole portion 107 on the second main surface 104 side is set to be the first diameter of the second hole portion 108.
The diameter of the first hole is slightly smaller than the diameter of the main surface 103 side, that is, the lower end of the second hole portion 108 on the first main surface 103 side is the upper end of the first hole portion 107 on the second main surface 104 side. The layers may be stacked with the inner periphery of the portion 107 exposed. The side surface conductor 109 in the laminating step is a dried metallized layer and contains a binder, and thus has a flexible state.

Further, since the protruding portion 117 projects inward from the periphery of the lower end (around the opening on the side of the first main surface 103) in the second hole portion 108, in other words, the opening of the protruding portion 117 has the second hole portion 108. Since the opening is smaller than the opening on the side of the first main surface 103, the protruding portion 117 also acts as a shielding region of the laser 119 from the side of the second main surface 104. Therefore, in this case, the side surface conductor 109 formed on the inner side surface of the first hole 107 is less likely to be irradiated with the laser 119. Therefore, the possibility that the laser 119 emitted from the second main surface 104 side may cause disconnection of the side surface conductor 109 or decrease in conductivity may be further reduced.

The individual wiring substrate 202 is, for example, the multiple-cavity wiring substrate of the above-described embodiment divided for each wiring substrate region 102. As a result, the wiring of the side surface conductor 109 is suppressed, and burrs and chips at the time of division are suppressed, so that it is possible to provide the wiring board 202 having excellent external dimension accuracy. Such a wiring board 202 is shown in FIGS. 2A and 2B in a top view and a bottom view.

As described above, the dividing groove 106 is formed by, for example, laser processing with high processing positional accuracy. In the insulating substrate of the wiring board 202, for example, the upper insulating layer 101a is thicker than the lower insulating layer 101b. In this case, the dividing groove 106 of the second main surface 104 in the mother substrate 101 before division is relatively deep (
For example, it may be deeper than the dividing groove 106 of the first main surface 103) so that the second main surface 104 side, that is, the upper insulating layer 101a side can be divided more easily. To make the dividing groove 106 relatively deep, for example, in the second hole 108, the opening on the second main surface 104 side may be made larger than the opening on the first main surface 103 side. As a result, when viewed from the second main surface 104 side, the inside surface of the second hole portion 108 can be seen through, and the laser 119 is likely to be irradiated deep into the second hole portion 108. Therefore, the dividing groove 106 formed on the second main surface 104 side (particularly in the vicinity of the second hole portion 108) becomes deeper, and the dividing property of the mother substrate 101 is further improved. This makes it possible to more effectively suppress burrs and chips at the time of division, and to provide the wiring board 202 with further excellent external dimension accuracy.

Further, as described above, since the possibility of disconnection of the side surface conductor 109 due to the laser 119 and a decrease in conductivity is reduced, the plated portions (connection conductors 111 and The exposed surface of the frame-shaped metallized layer 114 and the like can be more reliably electrically connected. Therefore, it is possible to more reliably supply the current for plating plating to the plating target part and deposit the electroplating.

Further, when the side surface conductor 109 is thicker at the end portion on the second main surface 104 side than at the end portion on the first main surface 103 side, the following effects can be obtained for the individual wiring board 202. That is, in order to divide the mother board 101 into the wiring boards 202, for example, the mother board 101 is pressed from the first main surface 103 side so that the first main surface 103 side is a valley (concave side), and bending stress is applied. When adding, a crack that progresses from the tip of the dividing groove 106 on the second main surface 104 side toward the first main surface 103 is more easily linearly advanced from the thick portion to the thin portion of the side conductor 109. be able to. This is for the following reason.

That is, since the thickness of the side surface conductor 109 has a gradient, and in the metallized conductor, there is a tendency for cracks to easily progress from a portion having a relatively large thickness to a portion having a small thickness. The cracks during division tend to progress from the larger side to the smaller side.
Therefore, it is possible to suppress bending of the crack in the advancing direction, and it is possible to vertically divide the side surface conductor 109 into two along the boundary 105 of the wiring board region 102. As a result, burrs and chips caused by the bending of cracks are suppressed. Therefore, it has excellent external dimension accuracy and side conductors.
It is possible to provide the wiring board 202 in which peeling of the 109 is prevented.

Next, a method for manufacturing a multi-cavity wiring board including the wiring board according to the embodiment of the present invention will be described with reference to FIGS. It should be noted that in the following description, description of points that are the same as those of the above-described multi-cavity wiring board and the like will be omitted.

First, as shown in FIG. 5A, a first ceramic green sheet (101b) having a first main surface 103 and serving as a lower insulating layer 101b is prepared, and a first hole is formed by punching with a mold or the like. A through hole (the through hole has no reference numeral) to be the portion 107 is formed. In order to have a structure in which the first hole 107 is narrowed inward from the end on the second main surface 104 side to the end on the first main surface 103 side, for example, the first main surface 103 side starts punching. The first ceramic green sheet (101b) may be punched in the thickness direction so that it becomes a surface. Thus, due to the clearance (gap) between the upper die (punch part) and the lower die (recess), the diameter of the punching end surface is larger than the diameter of the punching start surface, and a taper corresponding to this difference in diameter is formed. Open holes can be formed.

Next, as shown in FIG. 5B, a second ceramic green sheet (101 having a main surface corresponding to the second main surface 104 in the multi-cavity wiring substrate of the above embodiment and serving as the upper insulating layer 101a.
Prepare a). Also in this second ceramic green sheet (101a), a through hole (a through hole having no reference numeral) to be the second hole portion 108 is formed similarly to the through hole to be the first hole portion 107. Further, the central portion of the second ceramic green sheet (101a) is punched out to form an opening (no reference numeral) and processed into a frame shape. First frame-shaped second ceramic green sheet (101a)
By laminating on the ceramic green sheet (101b), a frame portion surrounding the mounting portion 110 in the multi-cavity wiring board of the above-described embodiment is formed. Here, the second hole portion 108 may be formed such that the opening on the second main surface 104 side is larger than the opening on the opposite side. Note that the through hole to be the second hole portion 108 and the opening portion for forming the frame portion may be collectively formed.

Next, as shown in FIG. 5C, a metal paste 205 to be the side surface conductor 109 is applied to the inner surface of the through hole of the first ceramic green sheet (101b). Specifically, it is as follows. First, the first ceramic green sheet (101b) is placed on a placing table having suction holes at positions corresponding to the holes, and the first ceramic green sheet (101b) is placed on the upper surface of the first ceramic green sheet (101b). A print mask having an opening for exposing the through hole of (101b) is placed. Then, the metal paste 205 is supplied from above the print mask into the through hole by sliding the squeegee, and the metal paste 205 is sucked through the suction hole. Through the above steps, the metal paste 205 can be applied to the inner surface of the through hole of the first ceramic green sheet (101b). The applied metal paste 205 is sintered during firing to become the side surface conductor 109 in the first hole 107.

Here, when the side surface conductor 109 is formed thicker at the end portion on the second main surface 104 side than at the end portion on the first main surface 103 side, for example, as shown in FIG. Therefore, when the metal paste 205 is supplied into the through hole to be the first hole portion 107 with a squeegee or the like, the metal paste 205 may be sucked in the direction from the smaller opening side to the larger opening side of the through hole. This allows
A part of the sucked metal paste 205 hangs down due to gravity on the side (lower side) of the opening of the through-hole that becomes the first hole 107, and the metal paste 205 is formed thick. Therefore, the side surface conductor 109 can be formed thicker at the end portion on the second main surface 104 side than at the end portion on the first main surface 103 side.

Next, as shown in FIG. 5(d), the second ceramic green sheet (101a) serving as the upper insulating layer 101a is laminated on the first ceramic green sheet (101b) serving as the lower insulating layer 101b, whereby the mother A ceramic green sheet laminate to be the substrate 101 is formed. The first hole 107 and the second hole 108 have a structure in which they communicate with each other after being laminated. The mother substrate 101 manufactured in the example of this embodiment includes, for example, a wiring conductor 113 and an auxiliary conductor 112 formed inside, and the auxiliary conductor 112 is an end portion of the side surface conductor 109 on the second main surface 104 side. It is connected to (the thick side of the side surface conductor 109) and the wiring conductor 113. The wiring conductor 113 and the auxiliary conductor 112 are formed, for example, by the same material and method as those described for the multi-cavity wiring board of the above-described embodiment.

As described above, when the first ceramic green sheet (101b) and the second ceramic green sheet (101a) are stacked on top of each other, the metal paste becomes the side conductor 109 due to the pressure at the time of pressurization (no reference numeral after application). A part of the upper end of) is deformed and the second hole portion 108 (through hole) side (
In some cases, the protruding portion 117 is formed by projecting upward (upward). Since the protruding portion 117 overlaps the auxiliary conductor 112 formed on the second ceramic green sheet (101a) on the exposed surface, the connection between the wiring conductors 113 can be further ensured.

In order to effectively form the protruding portion 117 of the side surface conductor 109, for example, as described above, the diameter of the first hole 107 on the second main surface 104 side is the first main portion of the second hole 108. The diameter is slightly smaller than the diameter on the surface 103 side, that is, the lower end of the second hole portion 108 on the first main surface 103 side is the upper end of the first hole portion 107 on the second main surface 104 side. The layers may be stacked with the inner periphery of 107 exposed.

After that, the ceramic green sheet laminate manufactured in this manner is fired at a high temperature, and the dividing grooves 106 are formed in the next step, whereby a multi-cavity wiring board can be manufactured.

Then, as shown in FIG. 5E, a laser 119 is irradiated onto the first main surface 103 of the first ceramic green sheet (101b) of the laminated body so as to pass through the through hole. The irradiation position of the laser 119 is the boundary 105 of the wiring board region (not shown in FIG. 5) in the multi-cavity wiring board of the above-described embodiment. Irradiation with the laser 119 is performed while sequentially moving the irradiation position along the linear boundary 105. By this laser processing, the dividing groove 106 is formed along the boundary 105. Note that FIG. 5E shows a state in which the mounting portion 110 is on the lower side and the laser 119 is irradiated from the first main surface 103 side.

The inner diameter of the first hole portion 107 is narrowed inward from the end portion on the second main surface 104 side to the end portion on the first main surface 103 side. Therefore, when the dividing groove 106 is formed in the mother substrate 101 by laser processing, the side surface conductor 109 in the first hole 107 is less likely to be irradiated with the laser 119, and the disconnection of the side surface conductor 109 is suppressed. That is, the end portion on the first main surface 103 side acts as a shield region for the laser 119.

Further, for example, on the first main surface 103 side, in order to improve the connectivity between the side surface conductor 109 and the external connection conductor 115, a ring-shaped conductor (not shown) is provided around the first hole portion 107. When it is formed, when the dividing groove 106 is formed in the mother substrate 101, the shielding effect against the laser 119 is more effectively obtained by the thickness of the ring-shaped conductor. Therefore, in this case, the side surface conductor 109 in the first hole portion 107 is more difficult to be irradiated with the laser 119, and the disconnection of the side surface conductor 109 is further effectively suppressed.

The second hole portion 108 communicates with the first hole portion 107, and when the opening on the second main surface 104 side is larger than the opening on the first main surface 103 side, the second main surface 104 side. When the dividing groove 106 is formed in the region of the upper insulating layer 101a with the laser 119, the laser 119 is likely to be irradiated to the depth of the second hole 108, and thus the dividing property of the mother substrate 101 can be improved. Therefore, in this case, the multi-cavity wiring board in which the disconnection and the decrease in the conductivity of the side surface conductor 109 are suppressed on the first main surface 103 side, and the divisibility of the mother board 101 is improved on the second main surface 104 side. Can be realized.

The wiring board and the electronic device of the present invention are not limited to the examples of the above embodiment, and various modifications may be made without departing from the scope of the present invention. For example, in the example of the above-described embodiment, the mother substrate 101 and the wiring substrate 202 are formed as one upper insulating layer 101a.
However, the mother board 101 and the wiring board 202 may be composed of three or more insulating layers (not shown). Further, the frame-shaped metallization layer 114 of the wiring board 202 is assumed to have the nickel plating layer and the gold plating layer deposited on the upper surface thereof, but the frame-shaped metallization layer 114 has, for example, iron. A metal frame (not shown) made of a nickel-cobalt alloy may be joined.

Further, although the first hole portion 107 and the second hole portion 108 are formed by punching using a die, they may be punched by a laser processing device. In this case, the irradiation start surface of the laser 119 tends to have a larger opening diameter than the end surface, and this can be applied to form the first hole portion 107 and the second hole portion 108.

Further, for example, not only the corners of the wiring board region 102 having a quadrangular shape in a plan view but also the first portions on the sides.
The hole 107 and the like may be provided.

101... Mother board
101a: upper insulating layer
101b...Lower insulating layer
102: Wiring board area
103... 1st main surface
104...Second main surface
105...boundary
106...dividing groove
107...First hole
108...Second hole
109... Side conductor
110...Mounting part
111...Connection conductor
112...Auxiliary conductor
113... Wiring conductor
114...Frame-shaped metallized layer
115...External connection conductor
117・・・Overhanging part
118...Castellation
119...Laser
202...wiring board
205・・・Metal paste

Claims (5)

An insulating substrate including a first insulating layer having a first main surface and a second insulating layer having a second main surface facing the first main surface;
A first castellation formed from the first main surface to the side surface;
A side surface conductor attached to the inner side surface of the first castellation,
At least a portion of the first castellation to which the side surface conductor is attached to the inner side surface is narrowed inward from the end portion on the second main surface side to the end portion on the first main surface side,
The second insulating layer is located on an end portion of the side surface conductor on the second main surface side,
The insulating substrate has a second castellation on the second main surface, the second castellation communicates with the first castellation, and the width on the second main surface side is the first castellation. A wiring board having a width larger than that of the main surface. The wiring board according to claim 1, wherein the side surface conductor is thicker at an end portion on the second main surface side than at an end portion on the first main surface side. An insulating substrate including a first insulating layer having a first main surface and a second insulating layer having a second main surface facing the first main surface;
A first castellation formed from the first main surface to the side surface;
A side surface conductor attached to the inner side surface of the first castellation,
At least a portion of the first castellation to which the side surface conductor is attached to the inner side surface is narrowed inward from the end portion on the second main surface side to the end portion on the first main surface side,
The second insulating layer is located on an end portion of the side surface conductor on the second main surface side,
The wiring board, wherein the side surface conductor is thicker at an end portion on the second main surface side than at an end portion on the first main surface side. A wiring conductor formed inside the insulating substrate and an auxiliary conductor formed inside the insulating substrate are provided, and the auxiliary conductor includes an end portion of the side surface conductor on the second main surface side and the side conductor. The wiring board according to any one of claims 1 to 3, which is connected to a wiring conductor. A wiring board according to any one of claims 1 to 4,
An electronic device having an electronic component mounted on the wiring board.

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