JPS59210691A - Circuit board for carrying semiconductor element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to improvements in wiring boards for mounting semiconductor elements.

A conventional wiring board for mounting a semiconductor element (hereinafter referred to as a wiring board) has a base that constitutes a semiconductor element mounting part 4 having a semiconductor element mounting pad 1 and a wiring part having a conductor 2, as shown in FIG. The insulator 3 is made of the same material, for example, alumina ceramics. The dissipation of heat generated from the mounted semiconductor element 5 shown in FIG. 2 depends on the thermal conductivity of the insulator 3 serving as the base material of the wiring board. therefore.

If the thermal conductivity of the insulator 3 is low, there is a disadvantage that the structure becomes complicated, such as installing a cooling plate 6 or forcing air cooling or water cooling to dissipate the heat generated from the semiconductor element 5. Ta. It is also a material with high thermal conductivity.

For example, if beryllia ceramics or silicon carbide is used as the entire base material, the above drawbacks can be overcome to some extent, but beryllia ceramics are very expensive, and it is still difficult to ensure insulation properties with silicon carbide. There was a drawback.

The object of the present invention is to provide a wiring board free of these drawbacks.

The present invention provides a wiring board in which a semiconductor element mounting part having a semiconductor element mounting pad and a wiring part having a conductor are formed on an insulator, and only the semiconductor element mounting part has a higher thermal conductivity than the insulator of the wiring part. The present invention relates to a wiring board using ceramics having high insulation properties and high insulation properties.

In the present invention, conductors include copper, silver, silver-palladium,
Gold, tungsten, molybdenum, etc. are used, and alumina, glass ceramics, phenol resin, glass-epoxy resin, etc. are used as the insulator for the wiring portion having the conductor. Furthermore, the ceramics used for the semiconductor element mounting part include silicon carbide, silicon nitride, and silicon carbide.
There are sintered bodies such as JA, but in the present invention, it is necessary that the sintered body has higher thermal conductivity and insulation properties than the insulator of the wiring part, and it is used in semiconductor devices as a sintered body that satisfies these conditions. Thermal expansion coefficient of silicon single crystal 3-4 x 10
In terms of reliability, it is preferable to use a silicon carbide sintered body having an insulating property close to -'/°C and 1010 Ωα or more.

Embodiments of the present invention will be described with reference to the drawings.

Example 1 96 parts by weight of alumina as a base material for a wiring board.

Alumina (24.5% by weight) and silica (
47.9% by weight), magnesia (18.7% by weight).

Calcia (4 parts by weight of glass powder consisting of 8,9 parts by weight,
8 parts by weight of butyral resin as a binder, 5 parts by weight of phthalate plasticizer DOP as a plasticizer, and 20 parts by weight of butanol as a solvent, 50 parts by weight of dichlorethylene
Parts by weight were added and mixed uniformly in a ball mill to form a slip, and a green sheet was obtained by tape casting.

In addition to the above, 96 parts by weight of alumina, 4 parts by weight of glass powder having the same components as above, 8 parts by weight of butyral resin, and 5 parts by weight of phthalate plasticizer DOP.

15 parts by weight of carpitol acetate, 2 parts by weight of terpineol
0 parts by weight was added and mixed uniformly in a sieve machine to obtain an insulating paste. Next, after punching out the above-mentioned green sheet 7 into the shape shown in FIGS. 3 and 4, tungsten paste (manufactured by Asahi Chemical, trade name 3TW-10001) was printed on one side of the above-mentioned green sheet 70 as shown in FIG. to form a conductor 2, and the above-mentioned insulating base)-1 is formed on the top surface of the conductor 2.
An insulating layer 9 was formed by printing. Note that the above-mentioned tungsten paste was printed on the through holes 10 in order to obtain conduction with the upper layer. After repeating this process twice, the above-mentioned tungsten paste was printed on the top layer to obtain what is shown in FIG.

Next, as shown in FIG. 6, a SiC sintered body 11 (Hitachi, trade name: 8C
-1011, the above-mentioned insulating paste 12 printed on the side surface was inserted. After that, it was heated to 1600 in a weakly reducing atmosphere.
C. for 30 minutes and fired to obtain a wiring board according to the present invention shown in FIG. In FIG. 7, reference numeral 13 indicates a joint between the SiC sintered body and the alumina sintered body on which the wiring is formed.

14 is a sintered body of alumina.

Example 2 The green sheet used in Example 1 was used as a base material for a wiring board, and the same process as in Example 1 was carried out to obtain the one shown in FIG. 5. This was heated at 1600℃ for 30 minutes in a slightly reducing atmosphere.
A wiring board with one through hole 8 was obtained by holding and firing for 1 minute. In this through hole 8, 33 parts by weight of silica, 45 parts by weight of alumina, and 10 parts by weight of lead oxide were added to the side surface of the SiC sintered body 11 used in Example 1.

A printed glass paste consisting of 3.5 parts by weight of calcia and 3.0 parts by weight of boron oxide was inserted.

Thereafter, it was fired at 900° C. in a nitrogen atmosphere to obtain a wiring board according to the present invention shown in FIG.

Example 3 SiC sintered body 11 was placed in the through hole 8 of the wiring board used in Example 2.
Instead, the glass paste used in Example 2 was printed on the side surface of the sintered body. Thereafter, it was fired at 900°C in a nitrogen atmosphere.

A wiring board according to the present invention shown in FIG. 7 was obtained.

Next, as shown in FIG. 8, electroless nickel plating 15 was applied to the wiring boards obtained in Examples 1, 2, and 3, and gold plating 16 was applied thereon. Thereafter, gold paste was printed on the chip mounting portion of the SiC sintered body 11 and the top of the Veri IJ sintered body, and then fired at 850° C. to obtain the chip mounting pad 1. Next, the semiconductor element 5 was mounted on the chip mounting pad 1 by gold-silicon eutectic bonding, and the gold wire 17 was wire bonded. Further, the aluminum cooling piece 6 was adhered to a wiring board using a silicone rubber adhesive to obtain a semiconductor device. In FIG. 81, reference numeral 18 indicates a joint between the wiring board and the cooling piece 6.

Next, as a result of measuring the thermal resistance (θja) of the conventional wiring board using alumina ceramic as the base material and the wiring board obtained in Examples 1, 2, and 3 according to the present invention, the heat dissipation performance was the first. As shown in the table.

I was able to improve it significantly.

In the present invention, since ceramics having higher thermal conductivity and insulating properties are used only in the semiconductor element mounting portion than the insulator in the wiring portion, the heat dissipation property generated from the mounted semiconductor element is improved. Also, even if a large number of semiconductor elements are mounted on the same wiring board.

Since it is mounted on insulating ceramics, sufficient insulation of each element is ensured. Furthermore, since ceramics with high thermal conductivity are used only in the part where the semiconductor elements are mounted, it can be manufactured at a lower cost than wiring boards that use beryllia ceramics for the entire base material.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional wiring board, FIG. 2 is a sectional view of a semiconductor device in which a semiconductor element is mounted on the conventional wiring board shown in FIG. A top view of the green sheet used for wiring boards, Figure 4 is A-A in Figure 3.
5 and 6 are cross-sectional views showing the manufacturing process of a wiring board according to an embodiment of the present invention, FIG. 7 is a cross-sectional view of a wiring board according to an embodiment of the present invention, and FIG. , a semiconductor element was mounted on a wiring board obtained according to the present invention as shown in FIG. This is a cross-sectional view of a semiconductor device with a cooling piece attached. Explanation of symbols 1...Semiconductor element mounting pad 2...Conductor 3...Insulator 4...Semiconductor element mounting portion 5...Semiconductor element 6...Cooling piece 7...Green sheet 8...Through hole 9...I-layer
10...Through hole 11...SiC sintered body 12
... Insulating paste 13 ... Joint part 14.
...Sintered body 15...Nickel plating 16...Gold plating 17...Gold wire 18...Joint portion 4 71 Fig. 3 Fig. 3 Fig. 438-

Claims (1)

[Scope of Claims] 1. A wiring board for mounting a semiconductor element, which includes a semiconductor element mounting part having a semiconductor element mounting pad and a wiring part having a conductor formed on an insulator. A wiring board for mounting a semiconductor element, which uses ceramics having higher thermal conductivity and insulation properties than the insulator of the wiring part only in the semiconductor element mounting part.