JPH08133873A - Soldering jig and its production - Google Patents

Abstract

PURPOSE: To obtain a soldering jig having long life by coating a surface of a substrate made of graphite with a liquid mixture containing TiB2 , a metal alkoxide, water, a solvent and a catalyst and heat-treating at a specific temperature to form an abrasion-resistant coating film. CONSTITUTION: A mixed slurry is prepared by compounding (A) TiB2 having particle diameter of about 0.5-5μm with (B) a metal alkoxide such as tetraethoxysilane at a weight ratio A/(A+B) of 25-75% and adding a proper amount of water, a solvent such as ethanol and a catalyst such as sulfuric acid to the mixture. The objective soldering jig having long life can be produced by applying the mixed slurry to a surface of a substrate made of a graphite having a bulk density of about 1.4-2.0g/cm<3> and a thermal expansion coefficient of (1.0-8.0)×10<-6> / deg.C and heating at 300-500 deg.C in an oxidizing atmosphere such as air and/or at 500-1300 deg.C in a non-oxidizing atmosphere such as N2 gas to form an abrasion-resistant coating film having a thickness of about 1-50μm and composed of about 50-98wt.% of TiB2 and about 2-50wt.% of an inorganic binder such as SiO2 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jig used for brazing members necessary for assembling a semiconductor device or the like, and particularly to a jig for brazing which has excellent heat resistance and wear resistance and has a long life. A technique for providing a tool.

[0002]

2. Description of the Related Art In the field of semiconductor devices, IC chips are attached to a package by soldering. In PGA, the heat sink is bonded to the substrate by silver brazing. In these processes, the components are assembled on a brazing jig and the brazing filler metal is sandwiched between the components to be bonded, typically in a reducing or inert atmosphere. Is performed. For example, FIG. 1 shows an example of a process of brazing a heat sink to a substrate.
In this process, for example, Cu-on the brazing jig 1
A heat sink material 2 made of a W alloy is placed, a silver solder 3 is placed thereon, and a substrate 4 is set. Then, the silver brazing material 3 is sandwiched between the heat sink material 2 and the substrate 4, and heat treatment is performed in a heating furnace to perform brazing.

For the brazing jig used in these processes, a carbon material which is easy to machine, excellent in heat resistance and inexpensive is generally used. However, the carbon material
Since the wear resistance is low, there is a problem that carbon particles fall off from the surface during use to contaminate the work environment or adhere to the product. Therefore, attempts have been made to solve the above-mentioned problems by applying a coating on the surface of the carbon material to improve wear resistance.

For example, Japanese Patent Application Laid-Open No. 61-276766 discloses a brazing jig made of graphite, in which a sliding surface with a component is covered with an epoxy resin,
After that, it is disclosed to form a hard and abrasion-resistant amorphous carbon (glassy carbon) thin film on the sliding surface by heating to about 1000 ° C. in an inert atmosphere.

Japanese Patent Laid-Open No. 6-166568 discloses that
Isotropic and has a thermal expansion coefficient of 1.5 × 10 ^-6~ 7.0 x 10^-6
℃^-1When processing a graphite material in the range of
Then, a graphite material is placed in the CVD furnace and hydrogen gas is used as a carrier gas.
And methane as a hydrocarbon gas is introduced into the furnace.
Reacts with 0.5 to 2 of pyrolytic carbon on the surface of the graphite material.
The processed powder in the pores of the graphite material is coated with a thickness of 5 μm
It is disclosed to contain and improve wear resistance.

On the other hand, in the technique disclosed in Japanese Patent Application Laid-Open No. 1-153578, in a carbon jig for brazing a ceramic component, a nitride (specifically, TiN) or a carbide is added to a portion in contact with the ceramic component. 1-10
The carbon jig is coated with μm to provide abrasion resistance.

[0007]

When brazing is carried out using a jig coated with an amorphous carbon film, there occurs a problem that discoloration of the solder occurs when the solder is heated and melted. In addition, since the wettability of the solder to the amorphous carbon film or the pyrolytic carbon film is relatively good, the solder is apt to adhere to the jig, and the contamination of the solder shortens the life of the jig. There is. In addition, the carbonaceous film
It was relatively weak against oxidation, and the surface could be corroded by oxidation at high temperatures. Further, since the amorphous carbon film and the pyrolytic carbon film require a heat treatment step at 1000 ° C. or higher, there is a problem that the manufacturing cost becomes high.

On the other hand, conventional carbide or nitride films are
Wear resistance is given to the surface of the carbon jig, but due to the difference in the coefficient of thermal expansion from the carbon base material, cracks and peeling can occur in a relatively short period against the heat cycle of heating and cooling in the brazing process It was likely to occur.

An object of the present invention is to solve the above problems and to provide a brazing jig having the following characteristics.

(1) It has excellent wear resistance. (2) Discoloration of solder does not occur.

(3) The wettability of the working surface with respect to solder is low, and contamination by solder is unlikely to occur.

(4) Relatively strong against oxidation. (5) The coating for imparting abrasion resistance is strongly bonded to the carbon substrate, and the coating does not peel off during repeated use.

(6) Long service life. (7) It can be manufactured relatively inexpensively and easily.

[0014]

A brazing jig according to the present invention is a brazing jig in which a wear-resistant coating is formed on the surface of a base material made of graphite. It is characterized by comprising titanium boride as a main component and an inorganic binder that binds it.

Also provided is a method for producing a brazing jig according to the present invention, which comprises the step of applying a mixed solution containing titanium boride, a metal alkoxide, water, a solvent and a catalyst to the surface of a base material made of graphite. The coating step and the base material coated with the mixed solution are heated at 300 ° C. to 50 ° C. in an oxidizing atmosphere.
By heating at a temperature of 0 ° C. and / or at a temperature of 500 ° C. to 1300 ° C. in a non-oxidizing atmosphere, titanium boride is bonded to the surface of the base material with a metal oxide. And a step of forming.

[0016]

In the present invention, a wide range of graphite materials can be used for the base material made of graphite. For example, bulk density of 1.
4 to 2.0 g / cm ³ , preferably 1.5 to 1.9 g /
cm ^3, flexural strength 100 to 1000 / cm ^2, preferably 130~1000kg / cm ^2, the thermal expansion coefficient of 1.
^{0 × 10 -6 /℃~8.0×10 -6 / ℃} , preferably 1.
The 0 × 10 ^-6 molded article comprising /℃~7.5×10 ^-6 / ℃ ranging graphite can be applied. Various types of molded products can be used, and for example, CIP molded products, molding products, and extrusion molded products can be applied. Furthermore, a mesophase-based graphite material can be preferably used.

In the present invention, a wear-resistant coating film composed of titanium boride as a main component and an inorganic binder that binds it is formed on a base material made of graphite. In the brazing jig, this coating is provided at least on the surface that comes into contact with the component to be brazed, that is, the working surface. The thickness of the coating can be, for example, 1 to 50 μm, preferably 5 to 30 μm. From the viewpoint of forming a uniform and smooth surface film, the thickness is 50 μm
The following are preferred. On the other hand, the thickness is preferably 1 μm or more in order to impart sufficient abrasion resistance to the graphite base material. It is also desirable to set the thickness of the coating in consideration of the size and tolerance of the parts used for brazing.

The proportion of titanium boride in the coating may be, for example, 50% by weight to 98% by weight, and more preferably 55% by weight to 85% by weight. Ceramic particles of TiB ₂ are preferably used for titanium boride, and the particle size thereof can be, for example, 0.5 to 5 μm, preferably 0.5 to 2 μm. The inorganic binder binds the TiB ₂ particles together. As the inorganic binder material, for example, silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), titanium oxide (Ti
O ₂ ) and the like can be mentioned. As the inorganic binder, for example, one having a melting point of 1000 ° C. or higher, preferably 1500 ° C. or higher is used. Considering the influence on the parts to be brazed using the jig, for example, semiconductor device parts, the inorganic binder does not contain elements such as Na and Fe, so that the parts are not contaminated with harmful elements. Those that are not afraid are desirable. From this point, silicon oxide is more preferable as the inorganic binder material. The proportion of the inorganic binder in the wear resistant coating is, for example, 2% by weight to 50%.
%, Preferably 15% to 45% by weight. Incidentally, the wear-resistant coating composed of titanium boride and the inorganic binder, within the range in which the effect of the present invention can be exerted,
It may contain other trace components.

In the production method of the present invention, first, titanium boride, metal alkoxide, water,
A mixed solution containing a solvent and a catalyst is applied. TiB ₂ ceramic particles are preferably used for titanium boride, and the particle size is 0.5 from the viewpoint of the adhesion of the film to be formed.
A surface roughness of the film to be formed,
From the viewpoint of slidability with respect to parts, 0.5 to 1 μm is more preferable. The content of titanium boride particles in the mixed liquid to be applied is preferably, for example, 25 to 75% by weight based on the total weight of the metal alkoxide and titanium boride particles. If this content is 25% by weight or less, the coating with good adhesion cannot be obtained due to the shrinkage of the film during the heat treatment. On the other hand, when the content exceeds 75% by weight, the binding force of the binder generated from the metal alkoxide is reduced, and the coating is likely to crack.

The metal alkoxide in the mixture is M
(OR)_nCan be represented by the general formula
After the decomposition and polymerization reactions, the bar that binds the titanium boride particles together
This is for generating an inder. Metal alkoxy
Is highly reactive, and undergoes hydrolysis and polymerization reactions to form metal-
It is easy to produce a polymer composed of oxygen bonds. And the ratio
Heat treatment at a comparatively low temperature may generate metal oxides.
You can Examples of metal alkoxides include tetra
Ethoxysilane (Si (OC₂H_Five)_Four), Tetrameth
Xysilane (Si (OCH₃)_Four), Tetrabutoxy
Run (Si (OC _FourH₉)_Four) Etc. Si alkoxy
Aluminium isopropoxide (Al (OC
₃H₇)₃) Al alkoxide, titanium isop
Ropoxide (Ti (OC₃H₇)_Four) Etc. Ti Al
Mention may be made of coxides. Brazing as described above
Considering the effect on the parts to be
Then SiO ₂It is more preferable to generate
It is more preferable to use an alkoxide of Si.

In the coating mixture, the water is for hydrolysis and the solvent is used for preparing a homogeneous solution. As the solvent, alcohols such as methanol, ethanol, propanol and butanol are mainly used, but other solvents such as ethylene glycol, ethylene oxide and xylene are also used. An acid, ammonia, or the like can be used as the catalyst. Acids include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, hydrofluoric acid and the like. A solution containing a metal alkoxide, water, a solvent and a catalyst can produce a metal oxide according to the sol-gel method,
This serves as a binder to bind the titanium boride particles together, resulting in a uniform and smooth coating. The application of the mixed liquid can be performed by various methods such as dipping and spraying.

The substrate coated with the mixed liquid is heated at a temperature of 300 ° C. to 500 ° C. in an oxidizing atmosphere and / or at a temperature of 500 ° C. to 1300 ° C. in a non-oxidizing atmosphere. Air can be used as the oxidizing atmosphere, and an inert gas atmosphere such as nitrogen or argon can be used as the non-oxidizing atmosphere. When heat treatment is performed at a temperature exceeding 500 ° C. in an environment where oxygen is present, T
Since iB ₂ is oxidized and peeling of the coating is likely to occur, it is desirable to heat at a temperature lower than that. On the other hand, the higher the heat treatment temperature, the easier the reaction of the metal alkoxide to the metal oxide proceeds, and the adhesive strength of the coating is improved. Therefore, when heat treatment is performed at a temperature of 500 ° C. or higher, heating in a non-oxidizing atmosphere in which oxygen does not exist, such as a nitrogen atmosphere, is desirable. By heat treatment,
A film of titanium boride bonded with a metal oxide is formed.

In the present invention, the coating composed of titanium boride and the inorganic binder imparts wear resistance to the brazing jig, as will be concretely shown below. Also, the wear resistant coating according to the present invention does not cause discoloration of the solder during brazing. The wettability of solder to the coating is poor,
The coating is not contaminated by solder.

Further, in the present invention, the coating film imparts oxidation resistance to the graphite base material as will be specifically described below. TiB ₂ can cause an oxidation reaction represented by the following formula at a high temperature of about 500 ° C.

[0025] _{2TiB 2 + 5O 2 → 2TiO 2} + 2B 2 O 3 , however, a relatively low melting point B ₂ O ₃ is, TiB ₂ particles in a semi-molten state or a molten state, blocks the inter-TiO ₂ particles, to a graphite substrate It can effectively block the attack of oxygen. This makes it possible to provide a brazing jig having resistance to oxidation at a high temperature to some extent.

The brazing jig according to the present invention can be used not only in a non-oxidizing atmosphere but also in an oxidizing atmosphere at a temperature of 600 ° C. or lower, more preferably 500 ° C. or lower. , Which has oxidation resistance.

Further, the coating composed of titanium boride and the inorganic binder according to the present invention strongly adheres to the graphite material and does not peel off even in the heat cycle. It is considered that this is due to the interaction between titanium boride and the inorganic binder. The coating formed in accordance with the present invention is homogeneous, smooth and adheres firmly to the substrate.

Furthermore, the coating according to the present invention can be formed at a relatively low temperature by the method described above. this is,
This leads to a reduction in manufacturing costs. The manufacturing method of the present invention is
Compared to VD and thermal spraying, it does not require a large-scale device, and provides a wear-resistant coating that is homogeneous and adheres firmly to the substrate by a simple method. Further, it is possible to easily and uniformly coat a substrate having a large area. A coating film formed from a liquid phase according to the method of the present invention and composed of ceramic particles and a binder is one that is more strongly bonded to a substrate and less likely to peel off than a carbide or nitride film formed by a CVD or thermal spraying process. It is believed that there is.

[0029]

【Example】

 Example 1 About 25 parts by weight of tetraethoxysilane, about 75 parts of ethanol
By weight, about 20 parts by weight of water, about 0.3 parts by weight of nitric acid
T with an average particle size of 1 to 1.5 μm in a metal alkoxide solution
iB₂Molded product made of graphite from a slurry mixed with particles
It was spray coated on. When preparing the slurry, TiB
₂The content of particles is metal alkoxide and TiB₂Total weight of
10% by weight, 50% by weight, 80% by weight
U TiB ₂To prepare three types of slurries and obtain
Each of the resulting slurries was spray coated. Coating thickness
The fineness was adjusted to 25 to 50 μm. The slurry is applied
The molded graphite product was placed at 250 ° C, 600 ° C, 1000 ° C, 1
6 at each temperature of 400 ° C under nitrogen atmosphere
Heat treated for hours. The results obtained after heat treatment are shown in Table 1.
stop. The heat treatment at 250 ° C did not result in sufficient drying.
Was. TiB₂At a content of 50% by weight, 600 ° C,
A preferable film was obtained by heat treatment at 1000 ° C.

[0030]

[Table 1]

Example 2 In a slurry having the above composition, a TiB ₂ particle and a metal alkoxide having a weight ratio of 1: 1 were spray-coated on a graphite molded product at a thickness of 25 to 50 μm, and then in a nitrogen atmosphere for 1 hour. Heated at a temperature of 600 ° C.

A cross section of the obtained brazing jig is schematically shown in FIG. In the brazing jig 10, a wear resistant coating 12 made of TiB ₂ and SiO ₂ is formed on a base material 11 made of graphite. The coating 12 is provided at least on the operating surface 11a on which the brazing component is to be placed. The thickness of the coating 12 can be, for example, about 5 to 10 μm.

The brazing jig thus obtained was evaluated for wettability with solder (Pb-50 wt% Sn). As a comparative example, a graphite jig coated with glassy carbon was also evaluated. The results are shown in Table 2. As shown in the table, the surface coated according to the present invention has relatively poor wettability to solder, and the discoloration of solder does not occur on the coating.

[0034]

[Table 2]

Further, the obtained brazing jig is H ₂ : N
_The film was held at 500 ° C. for 500 hours in a reducing atmosphere of ₂ = 1: 1, but no peeling of the film was observed.

Example 3 About 25 parts by weight of tetraethoxysilane, about 75 parts of ethanol
Parts by weight, about 20 parts by weight of water, about 0.3 parts by weight of nitric acid, about 58 parts by weight of TiB ₂ particles having an average particle size of 1 to 1.5 μm, about 30
Three types of slurries each containing 1 part by weight or about 16 parts by weight were prepared and spray-coated on the graphite-formed product. Next, the spray-coated base material was heat-treated in the air at 400 ° C. for 5 hours, and then heat-treated in a nitrogen atmosphere at 600 ° C. for 2 hours to form an abrasion resistant coating on the graphite base material. 7μ
The powder drop test and the oxidation test were performed on the samples each having a film of m to 40 μm formed. The dusting test, the apparatus shown in FIG. 3, by placing a weight 32 on the specimen 31, on alumina wrapping paper 33 Al ₂ O ₃ is dispersed adhered to the surface of the particle size 3 [mu] m 3
The amount of wear of the test piece was measured by sliding it down 10 times along a 0 ° inclined surface. The load on the test piece is 130 g / c
m ² . When the initial weight was W ₀ and the measured weight after the test was W, a value represented by 100 (W ₀ −W) / W ₀ (%) was obtained and evaluated. The smaller this value, the better the abrasion resistance. Also, in the oxidation test, 10 × 1
A test piece of 0 × 60 mm was set at 1 at a temperature of 1000 ° C.
The weight change (%) with respect to the initial weight after holding for 3 hours in an atmosphere containing 000 ppm of O ₂ was determined. A jig of only graphite showed a weight loss of about 1.2%. The above results are shown in Table 3. As shown in the table, it is understood that the brazing jig of the present invention is superior in both abrasion resistance and oxidation resistance to the glassy carbon coated jig and the uncoated jig.

[0037]

[Table 3]

Example 4 No. For the brazing jig of No. 3, H ₂ : N
After holding at 400 ° C for 1 hour in an atmosphere of ₂ = 1: 1,
After performing a heat cycle of returning to room temperature 225 times or 1650 times, the adhesiveness of the film, the composition of the film, and the film thickness were measured.
The composition of the film was evaluated by X-ray diffraction.

Regarding the adhesiveness of the film, 225, 1650
After using the batch, no significant difference was observed with the adhesive strength before the test. Similarly, regarding the composition of the film, no significant difference was found between before the test and after the use, the set film thickness before the test was maintained. As described above, it can be seen that the jig according to the present invention has a strong coating film and is bonded to the substrate, and has excellent durability.

[0040]

According to the present invention, it is possible to provide a brazing jig having excellent wear resistance and oxidation resistance and having a long life. When brazing is performed using the present invention,
There is no discoloration of the solder that has occurred in the conventional glassy carbon coated product, and the contamination of the solder is suppressed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing an example of a step of brazing using a brazing jig.

FIG. 2 is a cross-sectional view showing an example of a brazing jig according to the present invention.

[Fig. 3] Regarding a sample constituting a brazing jig,
It is a schematic diagram which shows the apparatus for performing a powder drop test.

[Explanation of symbols]

 10 Brazing jig 11 Base material 11a Working surface 12 Abrasion resistant coating

Claims (2)

[Claims] 1. A brazing jig in which a wear-resistant coating is formed on the surface of a base material made of graphite, wherein the wear-resistant coating is titanium boride as a main component.
A brazing jig, comprising an inorganic binder that binds it. 2. A step of applying a mixed solution containing titanium boride, a metal alkoxide, water, a solvent and a catalyst onto the surface of a base material made of graphite, and the base material coated with the mixed solution is oxidized. Heating at a temperature of 300 ° C to 500 ° C in an atmosphere and / or 500 ° C to 130 in a non-oxidizing atmosphere.
By heating at a temperature of 0 ° C., on the surface of the base material,
And a step of forming a coating film in which the titanium boride is bonded with a metal oxide.