JPH0512876B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printed wiring board on which electronic components are mounted.

[Conventional technology]

As a conventional printed wiring board, there is one in which a wiring layer is formed on a resin board.

[Problem to be solved by the invention]

In such a printed wiring board, when electronic components are mounted, the expansion coefficient of the resin plate is greater than that of the electronic components, so the amount of thermal expansion of the resin plate is greater than the amount of thermal expansion of the electronic components. So,
Electronic components may be damaged.

This invention was made to solve the above-mentioned problems, and an object thereof is to provide a printed wiring board in which mounted electronic components are not damaged.

[Means to solve the problem]

In order to achieve this object, in the present invention, in a printed wiring board on which electronic components are to be mounted, a resin plate on which a wiring layer is formed and an auxiliary plate having a small expansion coefficient are bonded together by thermocompression.

[Effect]

In this printed wiring board, the thermal expansion of the resin plate is suppressed by the auxiliary plate, so the amount of thermal expansion of the resin plate is reduced, so the amount of thermal expansion of the mounted electronic components and the amount of thermal expansion of the resin plate are reduced. are almost equal.

〔Example〕

FIG. 1 is a diagram showing a printed wiring board according to the present invention, and FIG. 2 is a sectional view showing a part of the printed wiring board shown in FIG. In the figure, 1 is an auxiliary plate made of invar, 2 and 3 are resin plates, and the auxiliary plate 1 and the resin plates 2 and 3 are bonded together by thermocompression. 4 is a hole provided in the auxiliary board 1; 5 and 6 are wiring layers formed on the surfaces of the resin boards 2 and 3, respectively; 7 is a through hole that connects the wiring layers 5 and 6; passes through the center of the hole 4. Reference numeral 26 indicates a protrusion protruding from the resin plates 2 and 3 of the auxiliary plate 1, and 27 indicates a mounting hole provided in the protrusion 26.

In order to manufacture such a printed circuit board, first, as shown in FIG. Prepare. Next, as shown in FIG. 3b, the auxiliary plate 1 and the resin plates 2 and 3 are bonded together by thermocompression. In this case, the resin of the resin plates 2 and 3 flows into the hole 4. Next, a through-hole hole 10 passing through the center of the hole 4 is provided. Next, Figure 3c
As shown in FIG. 2, a copper plating layer 11 is provided on the surfaces of the resin plates 2 and 3 and the inner surface of the through-hole hole 10 by performing electroless copper plating and electrolytic copper plating. Next, wiring layers 5 and 6 are formed by selectively etching the copper foils 8 and 9 and the copper plating layer 11.

In the printed wiring board, since the expansion coefficient of the auxiliary plate 1 is small, the thermal expansion of the resin plates 2 and 3 is suppressed by the auxiliary plate 1, so that the amount of thermal expansion of the resin plates 2 and 3 is reduced. For this reason, the amount of thermal expansion of electronic components mounted by direct bonding or electronic components mounted via lead wires and the resin plates 2, 3
Since the amount of thermal expansion is almost equal to the amount of thermal expansion, electronic components will not be damaged. Furthermore, if the protrusion 26 is attached to the housing, the heat emitted from the electronic components will be released through the auxiliary plate 1, thereby preventing damage to the resin plates 2, 3, electronic components, etc. due to heat. can.

FIG. 4 is a sectional view showing a part of another printed wiring board according to the present invention. In the figure, 13,
14 is an auxiliary plate made of invar, 12, 15, 1
6 is a resin plate, which includes auxiliary plates 13, 14, resin plate 12,
15 and 16 are bonded by thermocompression. 17 and 18 are holes provided in the auxiliary plates 13 and 14, respectively;
9 and 20 are two wiring layers formed on resin plates 15 and 16, respectively; 21 is a through hole that connects the wiring layers 19 and 20;
It passes through the center of 7 and 18.

In order to manufacture such a printed circuit board, first, as shown in FIG. Layer 19a, 2
Resin plates 15a and 16a on which 0a is formed and resin plates 15b and 16b having copper foils 22 and 23 on their surfaces are prepared. Next, as shown in FIG. 5b, the auxiliary plates 13, 14, the resin plates 15a, 15b, 16a,
16b is thermocompression bonded. In this case, the resin of the resin plates 15a, 16a flows into the holes 17,18. Next, a through-hole hole 24 passing through the center of the holes 17 and 18 is provided. Next, as shown in FIG. 5c, a copper plating layer 25 is provided on the surfaces of the resin plates 15 and 16 and the inner surface of the through-hole hole 24 by performing electroless copper plating and electrolytic copper plating. Next, by selectively etching the copper foils 22 and 23 and the copper plating layer 25, the resin plates 15 and 16 are etched.
Wiring layers 19 and 20 are formed on the surface.

In this printed wiring board, the auxiliary board 1
Since the expansion coefficient of resin plates 12 and 14 is small,
Since the thermal expansion of the resin plates 12, 15, 16 is suppressed by the auxiliary plates 13, 14, the amount of thermal expansion of the resin plates 12, 15, 16 is reduced. For this reason, the amount of thermal expansion of electronic components mounted by direct bonding or electronic components mounted via lead wires and the resin plates 12, 1
Since the amounts of thermal expansion of Nos. 5 and 16 are approximately equal, the electronic components will not be damaged.

In the above embodiment, the auxiliary plates 1, 13, and 14 made of Invar were used, but auxiliary plates made of Invar with copper layers on both sides, auxiliary plates made of resin-impregnated carbon fiber, quartz, aramid, etc. , an auxiliary plate made of molybdenum, etc. may be used. Also,
In the above embodiment, the single wiring layers 5 and 6 were formed on the resin plates 2 and 3, and the two wiring layers 19 and 20 were formed on the resin plates 15 and 16. A wiring layer may also be formed.

〔Effect of the invention〕

As explained above, in the printed wiring board according to the present invention, the amount of thermal expansion of the mounted electronic components and the amount of thermal expansion of the resin plate are approximately equal, so that the electronic components are not damaged. As described above, the effects of this invention are remarkable.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a printed wiring board according to the present invention, Fig. 2 is a sectional view showing a part of the printed wiring board shown in Fig. 1, and Fig. 3 is a diagram showing a part of the printed wiring board shown in Fig. 1 and Fig. 2. An explanatory diagram of a method for manufacturing a printed wiring board, FIG. 4 is a sectional view showing a part of another printed wiring board according to the present invention, and FIG. 5 is an explanatory diagram of a method for manufacturing the printed wiring board shown in FIG. 4. It is. 1... Auxiliary plate, 2, 3... Resin plate, 5, 6...
Wiring layer, 12... Resin plate, 13, 14... Auxiliary board, 15, 16... Resin plate, 19, 20... Wiring layer.

Claims (1)

[Claims] 1. A printed wiring board on which electronic components are to be mounted, characterized in that a resin plate on which a wiring layer is formed and an auxiliary plate with a small expansion coefficient are bonded together by thermocompression.