JPS62182172A - Method of joining ceramics to metal - 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] (Field of Industrial Application) The present invention relates to a method for joining ceramics and metals, and more specifically, a method for joining ceramics with metals such as copper, nickel, steel, molybdenum, and tungsten, which have a metallized layer on their surfaces. Regarding the joining method.

(Prior technology) Conventionally, semiconductor device pan cages, integrated circuit boards, structural parts (magnetron envelopes, hermetic terminals, electron tubes)
Bonded bodies made by bonding ceramics and metals are used in applications such as ceramics and metals.

Conventionally, as shown in FIG. 2, a ceramic 1 having a metallized layer 2 and a metal 3 having a larger opposing area than the ceramic 1 were joined via a brazing material 9, but the brazing material 9 was attached to the metal 3. As a result, the bonding area of the metal 3 is larger than that of the ceramic 1, and the stress on the ceramic 1 becomes larger due to the difference K in thermal expansion coefficient between the ceramic 1 and the metal 3.
There were drawbacks such as the crank 6 entering the interior, causing the ceramic 1 to break and the bonding strength to decrease.

In order to solve these drawbacks, Japanese Patent Application Laid-Open No. 59-1028
As described in Publication No. 76, a material (oxide ceramic layer and metal layer) having a coefficient of thermal expansion intermediate between that of non-oxide ceramics and metal is interposed between non-oxide ceramics and metal for bonding. How to do that, JP-A-60-90
As described in Japanese Patent No. 877, a thin metal plate with a low thermal expansion coefficient is brazed on the metallized surface of the S+C sintered body, and a part of the metal plate is bonded to other metals via the low thermal expansion metal plate, leaving a part unbonded. A method of joining them has been proposed.

(Problems to be Solved by the Invention) However, in the method shown in JP-A No. 59-102876 and the method shown in JP-A No. 60-90877, bonding is performed directly through an intermediate layer. There was a drawback that metal members could not be joined.

The object of the present invention is to provide a method for joining ceramics and metal without such drawbacks.

(Means for Solving the Problems) As a result of extensive research into the above-mentioned drawbacks, the inventors of the present invention placed a spacer thinner than the thickness of the brazing filler metal on the top of the metal facing the end of the ceramic metallized layer. The inventors have discovered that by using a metal with a larger facing area than ceramics, ceramics and metals can be directly bonded via a brazing filler metal without defects such as destruction of the ceramics or reduction in bonding strength.

The present invention is a method for edge-bonding ceramics with a metallized layer on the surface and metal to a brazing material, in which a spacer thinner than the thickness of the brazing material is placed on the upper part of the metal facing the end of the metallized layer, and The present invention relates to a method for joining ceramics and metal by joining a metallized layer and metal via a brazing material.

There are no particular restrictions on the type of ceramic used in the present invention, but non-oxide ceramics, which generally have a smaller coefficient of thermal expansion than oxide ceramics, such as silicon carbide, aluminum nitride, and silicon nitride, are preferred.

The metallized layer is formed using molybdenum.

Methods include a method of applying a paste containing a high melting point metal such as tungsten as a main component and firing, a method of directly plating copper, nickel, etc. on ceramics, a physical vapor deposition method, but there are no particular limitations in the present invention.

Further, as the brazing material used in the present invention, silver-copper eutectic brazing, silver brazing, copper brazing, gold brazing, etc. are used, and as the metal, copper, nickel, steel, molybdenum, tungsten, etc. are used.

As a spacer used when joining ceramics and metals, ceramics such as alumina and silicon carbide, which are difficult to wet with the brazing material, metals coated with ceramics, and the like are used. The thickness of the spacer needs to be thinner than the thickness of the brazing filler metal used; if it is thicker than the brazing filler metal, it becomes difficult to join the ceramic and metal.

(Example) An example of the present invention will be described below with reference to FIG. 1 of the drawings.

Example 1 Molybdenum paste TL was applied on a ceramic silicon carbide substrate (manufactured by Hitachi Seisakusho, trade name 5C-101) 7 with dimensions of 20 x 20 and thickness of 1.0 as shown in fa in Figure 1.
It was screen printed to a size of 8 mm x 18 mm and 20 μm thick, then baked at 1300°C for 1 hour in a slightly reducing atmosphere, and then electroless nickel plated (manufactured by Nippon Kanigen,
Product name 8-680) was applied to a thickness of 2 μm, and
A metallized layer 2 as shown in bl was formed.

On the other hand, the dimensions shown in FIG. 1(C) are 40 mm x 40 mm.

When silicon carbide substrate 7 is bonded to oxygen-free copper plate 8 using oxygen-free copper plate 8 with a thickness of 2, a silicon carbide coating is formed on the upper part of oxygen-free copper plate 8 facing the end of metallized layer 2. .1 wn stainless steel spacer 5 is placed inside it, 17.0mm x 17.0mm, thickness 0.2m
A silver-copper eutectic solder 4 of m was placed.

1 m As shown in FIG. 1(d), a silicon carbide substrate 7 provided with a metallized layer 2 was placed on an oxygen-free copper plate 8 on which a spacer 5 and a silver-copper eutectic solder 4 were placed.

After heating at 850° C. for 10 minutes in an H2 atmosphere and cooling, spacer 5 was removed and silicon carbide substrate 7 and oxygen-free steel plate 8 were joined as shown in FIG. 1(e). For comparison, similar bonding was also performed on an oxygen-free copper plate without a spacer. For comparative examples.

Although the ceramics were destroyed after bonding, no cranking was observed when the cross section was observed in the case where a spacer was placed and the oxygen-free copper plate was bonded.

Example 2 A silicon carbide plate having the metallized layer used in Example 1 was used as the ceramic, and a molybdenum plate having the same shape as the oxygen-free copper plate used in Example 1 as the metal was plated with nickel (
A material coated with Nippon Kanizen Co., Ltd. (trade name: S-680) to a thickness of 3 μm was used.

Thereafter, a silicon carbide substrate and a molybdenum plate were bonded together in the same manner as in Example 1. For comparison, similar bonding was also performed on a nickel-plated molybdenum plate without spacers. For comparative examples.

When the cross section was observed, cracks were observed from the edges of the metallized layer, but no cracks were observed when the molybdenum plates were bonded with spacers placed.

Example 3 A 96-chialumina substrate having the same shape as in Example 1 as a ceramic (manufactured by Hitachi Chemical Co., Ltd., trade name Halotsukusuna 552)
A molybdenum paste was screen printed on this substrate in the same manner as in Example 1, and 1,
After firing at 450° C. for 1 hour, nickel plating was applied in the same manner as in Example 1 to form a metallized layer. Further, as the metal, the oxygen-free copper plate used in Example 1 was used. These were joined in the same manner as in Example 1. For comparison, similar bonding was also performed on an oxygen-free copper plate on which no spacer was placed. In either case, no cranking from the metallized end was observed after joining. There -65°C
When a thermal shock test in liquid at ~+150°C was conducted for 100 cycles, cranking was observed from the edge of the metallized layer in the comparative example, but no cranking was observed in the case where a spacer was placed and bonded. I was not able to admit.

(Effects of the Invention) According to the bonding method of the present invention, the stress related to ceramics is reduced compared to the conventional method, so there are no drawbacks such as destruction of ceramics or reduction in bonding strength.

It becomes possible to directly join ceramics and metals via a brazing material.

[Brief explanation of drawings]

Fig. 1 o(al, (b), (c), (dl x and el) is a sectional view showing the manufacturing process of a joined body of ceramics and metal according to an embodiment of the present invention, Fig. 2 is It is a sectional view showing a joined body joined by a conventional method. Explanation of symbols 1...Ceramics 2...Metallized layer 3
...Metal 4...Silver-copper eutectic wax 5
...Spacer 6...Crank 7...
Silicon carbide substrate 8...Oxygen-free copper plate 9...Brazing material agent Patent attorney Kunihiko Wakabayashi 4:a-@3sa Fig. 1 Fig. 2

Claims (1)

[Claims] 1. In a method of joining ceramics with a metallized layer on the surface and metal using a brazing material, a spacer thinner than the thickness of the brazing material is placed on the top of the metal facing the end of the metallized layer, and the metallized layer is A method for joining ceramics and metal, which is characterized by joining ceramics and metal through a brazing material.