JPH0446478B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention improves heat dissipation from electronic components such as chip devices or semiconductor devices, blocks moisture from entering the electronic components from the outside, The present invention relates to a highly reliable electronic component mounting board that can be made thin and has a manufacturing method thereof.

[Conventional technology]

BACKGROUND ART Conventionally, electronic components such as semiconductor elements are directly mounted on a printed wiring board, and the board is electrically connected by wire bonding, and the board is used as an interior board for watches, cameras, and the like. (a) of the drawing (Figure 6) shown later is an example of a board in which a semiconductor element is directly mounted on a printed wiring board, and a ceramic board or an organic resin board is used as the printed wiring board. ing. As shown in FIG. 6(b), there is a printed wiring board in which a recess is formed on the surface of the substrate in a portion where a semiconductor element is mounted by counterbore processing or laminated molding, and a semiconductor element is mounted within the recess.

[Problem that the invention seeks to solve]

However, these conventional printed wiring boards do not provide sufficient heat dissipation for the heat generated from the semiconductor elements mounted on them, and are only applied to relatively low output semiconductor elements, that is, semiconductor elements that generate little heat. When mounting semiconductor devices for output, it is necessary to take measures such as providing heat dissipation fins. In particular, organic resin materials have lower thermal conductivity than metals and are inferior in heat dissipation from semiconductor elements. On the other hand, ceramic substrates such as alumina are not suitable for mounting recently highly integrated high output semiconductor devices. In addition, the disadvantage of using organic resin substrates as semiconductor mounting substrates is that their moisture resistance is very low compared to ceramic substrates. Organic resin substrates are used as semiconductor mounting substrates in fields where high reliability with respect to moisture resistance is required because moisture from the substrate passes through the substrate and reaches the semiconductor elements, corroding the semiconductor elements. It is difficult to do so.

The present invention eliminates and improves the drawbacks of the conventional printed wiring board, improves heat dissipation performance and moisture resistance,
Moreover, it is an object of the present invention to provide a substrate for mounting an electronic component and a method for manufacturing the same, which allows the substrate to be made thinner.

[Means for solving problems]

The method of manufacturing a substrate for mounting an electronic component according to the first aspect of the present invention has the following configuration. (a) forming through-holes 2 at locations on which electronic components are to be placed on a double-sided copper-coated printed wiring board 1 made of an organic resin material; (b) forming through-holes 2 on the back side of the board 1; (c) adhering a printed wiring board 4 made of an organic resin material, on which a through hole 3 having an opening larger than the through hole 2 is formed so as to surround the through hole 2, via an adhesive layer 5; (d ) A method of manufacturing a substrate for mounting an electronic component, comprising the step of forming a metal plating film 8 on both surfaces of the substrate including at least the recess 6 and the metal plate 7.

The method of manufacturing a substrate for mounting electronic components according to the second aspect of the present invention has the following configuration.

(a) A printed wiring board 4 made of an organic resin material and having a through hole is placed on the back side of the portion of the double-sided copper-coated printed wiring board 1 made of an organic resin material that corresponds to the area on which electronic components are to be mounted. (b) attaching the metal plate 7 to the inner bottom surface of the recess 9 via the adhesive layer 5; (c) from the surface of the substrate 1; , forming a recess 6 with an opening smaller than the through hole by counterboring the substrate 1 and the metal plate 7 so that the metal plate 7 is exposed at the location where the electronic component is to be mounted; d) A method for manufacturing a board for mounting an electronic component, comprising the step of forming a metal plating film 8 on both surfaces of the board including at least the recess 6 and the metal plate 7.

The electronic component mounting board according to the third aspect of the present invention has the following configuration.

A laminated board in which a printed wiring board 4 made of an organic resin material is laminated on the back side of a double-sided copper-coated printed wiring board 1 made of an organic resin material with an adhesive layer 5 interposed therebetween, and an electronic component mounting part of the laminated board. is installed in a through hole for mounting an electronic component formed in the substrate 1 and a through hole for mounting a metal plate formed in the substrate 4, which has an opening larger than the through hole, and an adhesive layer is provided on the back side of the substrate 1. a metal plate 7 that closes the through hole for mounting the electronic component on the electronic component tower, and is continuous with the inner wall of the through hole for mounting the electronic component on the surface of the metal plate 7, and a metal plate for mounting the metal plate An electronic component tower characterized in that a continuous metal plating film 8 is formed on the inner wall of the through hole and the surface of the metal plate 7, and further, the metal plating film 8 is in contact with a metal layer 10 on the back side of the substrate 1. Mounting board.

In the manufacturing method of the present invention, a known electroless copper plating method can be used as a method for forming a metal plating film on the printed wiring board made of an organic resin material. For example, there is a known through-hole plating method in which when plating through-holes, the substrate surface or its recesses are simultaneously plated (Japanese Patent Application Laid-Open No. 59-67686).

Similarly, as a method for applying metal plating to the surface of the above-mentioned substrate, the known electroless plating method (chemical plating method) is disclosed in Japanese Patent Application Laid-open No. 145856/1985, Japanese Patent Publication No. 9024/1982, etc. There is.

[Action and effect]

By adopting the above configuration, the present invention can improve heat dissipation, which is a drawback of conventional printed wiring boards. In other words, it is a board for mounting electronic components, in which a metal plate is attached to the bottom of the recess on the back side of the printed wiring board via an adhesive layer, and a metal plating film is formed on the metal plate and the surface of the board. Heat generated from electronic components such as elements can be efficiently dissipated through the metal plate, and the entire board can be made thinner.

Moreover, because of the metal plating coating that covers the recess where the electronic components are mounted and the area where the metal plate on the back side of the recess contacts the board, external moisture can pass through the adhesive layer and the board. This makes it possible to block the intrusion into the mounting section.

The electronic component mounting board of the present invention and the electronic component mounting board manufactured by the manufacturing method of the present invention have high heat dissipation properties, so even if electronic components that generate a large amount of heat are mounted on the board, heat will not be accumulated on the board. In addition, there is little chance of external moisture entering the mounted electronic components through the board, which improves the durability of the electronic components and has the advantage that the board on which the electronic components are mounted can be made thinner after mounting.

The present invention will be specifically explained below based on the drawings.

First, for convenience, the steps shown in FIGS. 2 and 3 of the manufacturing method of the electronic component mounting board of the present invention will be explained.

In Figure 2, a is a double-sided copper-coated printed wiring board 1.
2 is a longitudinal cross-sectional view in which a through hole 2 is formed by punching, router processing, counterbore processing, etc. at a location where an electronic component is to be mounted. Typical printed wiring boards are glass fiber reinforced epoxy resin boards,
These include paper phenol resin substrates, paper epoxy resin substrates, glass polyimide resin substrates, glass triazine resin substrates, etc. A copper coating such as copper foil 10 must be formed on both sides of these substrates in advance. Next, as shown in FIG. 2B, a printed wiring board 4 made of the organic resin material having a through hole 3 larger than the through hole is placed on an adhesive layer so as to surround the through hole 2 from the back side of the printed wiring board 1. FIG. 5 is a vertical cross-sectional view of the structure in which the layers are laminated with each other. The adhesive layer 5 may be an uncured epoxy resin-impregnated glass cloth, a heat-resistant adhesive sheet, a liquid resin, or the like, and an adhesive layer with high properties such as adhesiveness, heat resistance, and durability is preferable. c in FIG. 2 is a concave portion which covers the through hole 2 where the electronic component is to be mounted from the back side of the printed wiring board 1, and where the electronic component is to be mounted is on the front side of the printed wiring 1. 6 is a vertical cross-sectional view of a state in which a metal plate 7 is attached via an adhesive layer 5. The metal plate may be any material having relatively high thermal conductivity, such as copper, copper alloy, iron, iron alloy, aluminum, aluminum alloy, or the like. Although the size and thickness of the metal plate are not particularly limited, a thicker plate and a larger surface area are advantageous in improving heat dissipation. As shown in FIG. 4 a and b, the method for determining the mounting position of the metal plate is as shown in FIG. c, d in Figure 4
It is advantageous to determine the mounting position of the metal plate by deforming at least two sides or corners of the planar shape of the metal plate 7, as shown in FIG. In d of FIG. 2, a metal plating film 8 is formed on both sides of the substrate including at least the recess 6 and the metal plate 7,
FIG. 2 is a vertical cross-sectional view of printed wiring boards 1 and 4 and a metal plate 7 integrated together. The metal plating film 8 has the effect of blocking water from entering into the adhesive layer between the printed wiring board 1 and the metal plate 7, and preventing water from entering into the mounting portion of the electronic component. By integrating 10 with a metal plating film, the heat generated from the electronic component is quickly conducted from the metal plate to the copper foil and radiated to the outside, which has the advantage of improving the heat dissipation effect. FIG. 2e is a longitudinal cross-sectional view of a state in which a semiconductor element 12 is mounted on a substrate for mounting an electronic component according to the present invention, connected by wire bonding, and the semiconductor element and its surrounding area are sealed with a resin 14. In this drawing, 14 is a sealing resin, such as epoxy resin or silicone resin. Further, 15 is a weir frame for preventing the sealing resin from flowing out.

3a is larger than the opening of the recess 6 formed at the location where the electronic component is to be mounted from the back side of the portion of the printed wiring board 1 corresponding to the location where the electronic component is to be mounted A printed wiring board 4 having a through hole 3 surrounding the recess is attached to an adhesive layer 5.
FIG. 3 is a longitudinal cross-sectional view of a state in which a recessed portion 9 is formed by adhering via a . FIG. 3B is a longitudinal cross-sectional view of a state in which a metal plate 7 is adhered to the inner bottom surface of a recess 9 formed on the back side of the printed wiring board 1 via an adhesive layer 5. FIG. 3c shows a state in which the recess 6 is formed by counterboring so that a part of the metal plate 7 is exposed at the location on the opposite side of the back surface where the recess 9 is formed, where the electronic component is to be mounted. FIG. FIG. 8d is a vertical cross-sectional view of a state in which the printed wiring board 1 and the metal plate 7 are integrated by forming a metal plating film 8 on both surfaces of the board including at least the recess 6. FIG. 2e is a longitudinal cross-sectional view of a semiconductor element 12 mounted on an electronic component mounting board according to the present invention and sealed with resin 14. The printed wiring board of the present invention manufactured in this manner has the characteristics shown in the longitudinal sectional view of FIG. The feature is that the front side of the double-sided copper-coated printed wiring board 1 made of an organic resin material has a recess 6 on which a conductor circuit and electronic components are to be mounted, and the recess 6 is in contact with a metal plate 7 on the back side. The substrate 1 has at least a metal plating film 8, and the back side of the substrate 1 has a metal layer 10 such as copper foil, and the printed wiring board of the substrate 1 in which the through hole 3 is formed in advance is laminated and The through hole 3 becomes a recess 9 on the back side of the laminated substrate, and a metal plate 7 is adhered to the recess 9 via an adhesive layer 5.
A metal coating 8 is formed on both the metal plate 7 and the laminated substrate. FIG. 5 is a perspective view of the plug-in package board of the present invention. This is a plug-in package in which a large number of conductor pins 18 are arranged in a circumferential row in through holes 16 provided on the outer periphery of the electronic component mounting board. A thermosetting resin sheet 17 is adhered to the outer circumference of the substrate and the through holes 16 shown in the shaded area 17 .
This is to completely coat the through holes.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a printed wiring board of the present invention, FIGS. 2 and 3 are longitudinal cross-sectional views of the board showing a flow sheet of a method for manufacturing a printed wiring board of the present invention, and FIG. 4 is a longitudinal cross-sectional view of the printed wiring board of the present invention. FIG. 5 is a plan view of the substrate of the alignment section for attaching the metal plate to the substrate of the present invention, FIG. 5 is a perspective view of the plug-in package substrate of the present invention, and FIGS.
b is a vertical cross-sectional view of a conventional electronic component mounting board. DESCRIPTION OF SYMBOLS 1, 4... Printed wiring board, 2, 3... Through hole, 5... Adhesive layer, 6... Recess (recess for electronic component mounting) 7... Metal plate, 8... Metal plating layer, 9... Recess (metal plate mounting) recess) 10...Copper foil, 11...Solder resist mask, 12...Semiconductor element, 13...Bonding wire, 14...Sealing resin, 15...Resin sealing frame, 16...Through hole, 17...Thermosetting resin sheet, 18 ...Conductor pin.

Claims (1)

[Claims] 1. (a) forming a through hole 2 at a location on which electronic components are to be mounted on a double-sided copper-coated printed wiring board 1 made of an organic resin material; (b) a step on the back surface of the board 1; a step of bonding a printed wiring board 4 made of an organic resin material, on which a through hole 3 having an opening larger than the through hole 2 is formed so as to surround the through hole 2, via an adhesive layer 5; , (c) A metal plate 7 is placed on the back side of the substrate 1 via an adhesive layer 5 so that the through hole 2 is closed and the place where the electronic component is to be mounted is a recess 6 on the front side of the substrate 1. (d) forming a metal plating film 8 on both surfaces of the substrate including at least the recess 6 and the metal plate 7. 2 (a) A printed wiring board 4 made of an organic resin material and having a through hole on the back side of the portion of the printed wiring board 1 made of an organic resin material and corresponding to the area where electronic components are to be mounted. (b) attaching the metal plate 7 to the inner bottom surface of the recess 9 via the adhesive layer 5; (c) the surface of the substrate 1; forming a recess 6 having an opening smaller than the through hole by counterboring the substrate 1 and the metal plate 7 so that the metal plate 7 is exposed at a location where the electronic component is to be mounted; (d) A method for manufacturing a board for mounting electronic components, comprising the step of forming a metal plating film 8 on both sides of the board including at least the recess 6 and the metal plate 7. 3 A laminated board in which a printed wiring board 4 made of an organic resin material is laminated on the back side of a double-sided copper-coated printed wiring board 1 made of an organic resin material via an adhesive layer 5, wherein electronic components are mounted on the laminated board. The part is installed in the through hole for mounting an electronic component formed in the substrate 1 and the through hole for mounting a metal plate formed in the substrate 4, which has an opening larger than the through hole, and is adhered to the back side of the substrate 1. It consists of a metal plate 7 that closes the through hole for mounting the electronic component on the electronic component tower, which is bonded via a layer 5, and is continuous with the inner wall of the through hole for mounting the electronic component on the surface of the metal plate 7, and the metal plate is attached to the metal plate 7. An electronic component characterized in that a continuous metal plating film 8 is formed on the inner wall of the through-hole and the surface of the metal plate 7, and further, the metal plating film 8 is in contact with the metal layer 10 on the back side of the substrate 1. Tower mounting board.