JP4585379B2 - Method for producing metal-ceramic composite material - Google Patents

Description

  The present invention relates to a method for producing a metal-ceramic composite material, and more particularly, to a method for producing a metal-ceramic composite material excellent in durability in which a matrix is a Si-Al alloy.

  In general, a semiconductor chip forming a semiconductor integrated circuit is housed in a ceramic or plastic package and used for various electronic devices. Such a package not only performs various functions such as protection of a semiconductor chip, mounting on a board (substrate), and transmission of an electric signal between the semiconductor chip and the substrate, but also quickly generates heat generated in the semiconductor chip to the outside. It also has a role to dissipate.

  In recent years, higher integration of circuits in a semiconductor chip has progressed, and as the operation speed of the circuit has improved, the power consumption of the semiconductor chip has greatly increased, and the amount of heat generated by the semiconductor chip has also increased rapidly. The heat generated in the semiconductor chip not only causes a reduction in the life of the element, but also has a different coefficient of thermal expansion due to the different components of the semiconductor chip and the package, resulting in stresses generated in the semiconductor chip. This causes problems such as cracking and peeling of the semiconductor chip from the package.

  Therefore, in order to solve such a problem, a method is used in which a board or a package is made of a high thermal conductivity material, or a heat dissipation substrate made of a high thermal conductivity material is adhered to the package. However, when the thermal expansion coefficient of such a high thermal conductivity material is significantly different from the thermal expansion coefficient of a semiconductor chip or the like, cracking or peeling due to thermal stress occurs. Therefore, it is desired to provide a material having a low thermal expansion coefficient close to that of a semiconductor chip or board and having high thermal conductivity, and AlN (aluminum nitride) is widely used as the material. It is coming.

However, although the thermal expansion coefficient of AlN is 5 × 10 ⁻⁶ / ° C., which is a relatively low value, it is larger than that of the semiconductor chip (3 to 4 × 10 ⁻⁶ / ° C.). In order to cope with the diversity of electronic device members, a material having a variable width in thermal expansion coefficient is desired. However, with a single material such as AlN, it is difficult to arbitrarily control the thermal expansion coefficient.

  Therefore, the present inventors have made SiC (silicon carbide) particles or SiC fiber as a reinforcing material as a thermally conductive material capable of arbitrarily controlling the thermal expansion coefficient, and the matrix is made of Si (metal silicon) -Al (metal aluminum) alloy. Have been proposed (see, for example, Patent Document 1). This material can be manufactured by preparing a preform made of a reinforcing material and an organic binder and allowing molten Si and molten Al to permeate the preform. The coefficient of thermal expansion can be adjusted by changing the volume ratio of the reinforcing material to the matrix or the composition ratio of the matrix.

However, when molten Si and molten Al simultaneously penetrate into carbon generated from the organic binder added to the preform, it is difficult to suppress the formation of Al ₄ C ₃ (aluminum carbide) due to the reaction between carbon and molten Al. . It is known that this aluminum carbide reacts with moisture in the air and its structure collapses while generating methane. That is, the formation of aluminum carbide causes a problem that the durability of the material is lowered.
JP 2002-294358 A

  The present invention has been made in view of such circumstances, and provides a method for producing a metal-ceramic composite material in which the formation of aluminum carbide is prevented, the durability is excellent, SiC is a reinforcing material, and the matrix is a Si-Al alloy. The purpose is to provide.

According to the present invention, there is provided a method for producing a metal-ceramic composite material in which one or both of SiC powder and SiC fiber are dispersed in a Si-Al alloy matrix,
Providing a preform including any one or both of SiC powder and SiC fiber, and one or both of an organic binder and a carbon material;
Storing solid Al in a container that is impermeable to molten Al and permeable by reacting with molten Si, and placing the container, the preform, and solid Si in a furnace;
Heating the inside of the furnace to a temperature exceeding the melting point of Si,
In the heating step, molten Si generated by melting the solid Si is infiltrated into the preform to obtain a SiC / Si composite material, and then the molten Si is infiltrated into the container to melt the container with Al. By allowing the molten Al formed by melting the solid Al in the container to flow out of the container, the molten Al is interdiffused with the molten Si in the SiC / Si composite material. A method for producing a metal-ceramic composite material is provided.

In this method for producing a metal-ceramic composite material, the container containing solid Al is placed on a preform separate from the product, containing SiC powder, SiC fiber, or both, and an organic binder. It is also preferable to use the method to do. Further, the filling rate of SiC and the Al content in the Si-Al alloy so that the thermal expansion coefficient of the metal-ceramic composite material is 2.7 × 10 ⁻⁶ / ° C. or more and 17.4 × 10 ⁻⁶ / ° C. or less. It is preferable to adjust either or both of the rates.

According to the present invention, only melted Si permeates into the preform at a temperature equal to or higher than the melting point of Si first, and then the molten Al and the molten Si are interdiffused to prevent reaction between carbon in the preform and molten Al. can do. Thus is prevented the generation of Al ₄ C ₃ is a metal having excellent durability - it is possible to obtain a ceramic composite material. In the production of this metal-ceramic composite material, the coefficient of thermal expansion can be controlled over a wide range to a value approximating that of a semiconductor chip or various electronic device members (hereinafter referred to as application members). Thereby, generation | occurrence | production of the distortion by the difference with the thermal expansion coefficient of an application member can be suppressed, and the outstanding durability can be acquired now.

  Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 shows a metal-ceramic composite material (hereinafter referred to as “SiC / Si—Al composite material”) in which one or both of SiC powder and SiC fiber are dispersed in a Si—Al alloy matrix according to the present invention. It is a figure which shows the manufacturing process of () typically.

  First, for example, a preform 10 formed of one or both of SiC powder and SiC fiber and an organic binder is prepared. This preform 10 can be manufactured by a known method. For example, the preform 10 can be obtained by mixing one or both of SiC powder and SiC fiber and an organic binder, filling the powder thus prepared in a molding die, and press-molding.

  The filling rate (volume fraction) of SiC in the preform 10 can be controlled by changing the average particle size and particle size distribution of the SiC powder, the aspect ratio of the SiC fiber, and the like. For example, even when the average particle size is the same, when using SiC powder with a narrow particle size distribution, compared to using SiC powder with a wide particle size distribution such that fine particles enter gaps between coarse particles. , SiC filling rate becomes small. In addition, the organic binder which comprises the preform 10 reacts with molten Si after becoming carbon (carbon) in the heat treatment performed later, and becomes SiC. Accordingly, the SiC filling rate in the finally obtained SiC / Si—Al composite material is higher than the SiC filling rate in the preform 10.

  Further, a container 11 that is impermeable to molten Al but becomes permeable to molten Al by reacting with molten Si is prepared. As this container 11, what consists of carbon materials (for example, carbon fiber fabric, CFRP, a carbon sheet) is used suitably. A container made of such a carbon material is impermeable to molten Al. However, since the carbon material is reactive with molten Si, it changes into SiC in contact with molten Si, as will be described later. Then, when the molten Si penetrates into the gap between the generated SiC, the container is changed to a container having a substantially continuous Si path.

  Next, as shown in FIG. 1 (a), solid Al12 is accommodated in a container 11, the container 11, the preform 10, and solid Si13 are accommodated in an outer frame container 14, and the outer frame container 14 is further placed in a furnace ( (Not shown). These solid Al12 and solid Si13 may be any of powder, granule, and lump, but it is preferable to use one having no oxide film formed on the surface as much as possible. Therefore, if it is the same weight, the lump-shaped thing with a small surface area is suitable. As the outer frame container 14, one made of alumina or carbon is preferably used.

  Then, the inside of the furnace is heated to a temperature (for example, 1600 ° C.) exceeding the melting point of Si (about 1410 ° C.) in a non-oxidizing atmosphere such as an inert gas atmosphere or a vacuum atmosphere. In this temperature raising process, the organic binder contained in the preform 10 is decomposed to generate carbon. Further, since the melting point of Al is about 660 ° C., the melting of the solid Al 12 starts at this temperature as shown in FIG. The molten Al 12a thus produced does not flow out of the container 11 because the container 11 is impermeable to the molten Al 12a. Further, when the temperature reaches about 1410 ° C., the melting of the solid Si 13 starts as shown in FIG.

  The molten Si 13a penetrates into the preform 10, and carbon contained in the preform 10 reacts with the molten Si 13a to generate SiC. Thus, the preform 10 is changed to a SiC / Si composite material 10a in which molten Si penetrates between SiC particles or SiC fibers.

  On the other hand, the molten Si 13a also reacts with the container 11 as shown in FIG. That is, the carbon material which comprises the container 11 contacts and reacts with molten Si13a, and changes to SiC. Then, the molten Si permeates into the gap between the generated SiCs, whereby the container 11 is changed to a container 11a having a substantially continuous Si path. As a result, as shown in FIG. 1 (d), the molten Al 12a in the container 11a can flow out of the container 11a using this communicating Si path.

The molten Al 12a that has flowed out of the container 11a thus interdiffuses with the molten Si 13a in the SiC / Si composite material 10a derived from the preform 10 to produce a Si—Al alloy. Since there is no carbon component in SiC / Si composite material 10a (because the carbon component that was present in preform 10 has already been changed to SiC), molten Al12a is converted into SiC / Si composite material 10a. Even if it permeates, Al ₄ C ₃ is not generated. A SiC / Si-Al composite material can be obtained by cooling the furnace after a sufficient time for mutual diffusion between the molten Al 12a and the molten Si 13a.

According to such a method for producing a SiC / Si—Al composite material, generation of Al ₄ C ₃ can be prevented, so that the structure does not collapse over a long period of use, and the SiC / Si excellent in durability. -Al composite material can be obtained.

In the manufacturing method of the SiC / Si—Al composite material described above, when the thickness of the target SiC / Si—Al composite material is large and a long time is required for the penetration of molten Si into the preform 10. The diffusion of the molten Al flowing out of the container 11 may start before the penetration of the molten Si into the preform 10 is completed. In that case, Al ₄ C ₃ may be generated.

Therefore, in order to prevent the formation of Al ₄ C ₃ , it is preferable to install a preform 15 different from the product under the container 11 as shown in FIG. If it does in this way, since the molten Si reaches the container 11 and the start time of the reaction in which SiC is generated can be delayed, the outflow start time of the molten Al from the container 11 can be delayed. Furthermore, by appropriately setting the thickness of the preform 15, the molten Al can be caused to flow out of the container 11 in accordance with the end timing of the penetration of the molten Si into the preform 10.

The thermal expansion coefficient of the SiC / Si—Al composite material produced in this way is determined by the filling rate of SiC (powder, fiber) as a reinforcing material in the SiC / Si—Al composite material and the Al in the Si—Al alloy. by adjusting one or both of the content, preferably controlled to a desired value in the range of ^{2.7 × 10 -6 /℃~17.4×10 -6 / ℃} . The higher the filling rate of SiC (powder, fiber) and the lower the Al content in the Si-Al alloy, the smaller the thermal expansion coefficient of the SiC / Si-Al composite material, and a value approximated to a semiconductor chip. It can be. Conversely, the smaller the filling rate of SiC (powder, fiber) and the higher the Al content in the Si-Al alloy, the higher the coefficient of thermal expansion of the SiC / Si-Al composite material, approximating that of a metal material. It becomes the value.

  As a modification of the above-described method for producing a SiC / Si-Al composite material, a preform was prepared by mixing one or both of SiC powder and SiC fiber, carbon powder, and an organic binder. Examples thereof include a method in which powder is filled in a molding die and press-molded. In addition, a preform manufactured using an organic binder may be placed in a furnace for infiltrating molten Si and molten Al after being heated to a predetermined temperature to decompose the organic binder into carbon (carbon). . However, the preform obtained by decomposing the organic binder is required to maintain its shape easily even if it is conveyed.

  In addition, when a press molding method is used, the preform can be molded by mixing one or both of SiC powder and SiC fiber and carbon (carbon) powder without using an organic binder. is there. Furthermore, preform molding is not limited to the press molding method, and a known ceramic molding method such as an extrusion molding method, an injection molding method, or a casting molding method can be used.

  As the container 11, you may use what combined Si board and Si grain | grains with carbon materials, such as a carbon fiber fabric. Since this Si plate and Si grains melt and react with the carbon material when heated above the melting point of Si, there is an effect of accelerating the outflow of molten Al. Therefore, for example, when a SiC / Si-Al composite material is manufactured using a thin preform, the penetration of molten Si into the preform is also fast, so that the outflow of molten Al is accelerated and the processing time is increased. It becomes possible to shorten.

Next, examples of the present invention will be described.
Example 1
SiC powder (# 400 manufactured by Shinano Denki Smelting Co., Ltd., average particle size 30 μm): 100% by mass, phenol resin as an organic binder: 10% by mass (5% by mass in terms of carbon) was mixed, and 200 by press molding. It was molded into a rectangular parallelepiped shape of × 200 × 10 mm. The molded body was heated at 1000 ° C. for 3 hours in an Ar atmosphere to obtain a SiC preform.

  Next, a predetermined amount of solid Al was accommodated in a carbon sheet container, and this container, a predetermined amount of solid Si, and the SiC preform prepared earlier were placed in a furnace. Here, the mass ratio of solid Al to solid Si (solid Al: solid Si) was 25 mass%: 75 mass%. Next, the furnace was heated to 1600 ° C. in an Ar atmosphere and held for 3 hours. The filling rate of SiC in the SiC / Si-Al composite material thus obtained was 50% by volume. This value is obtained by density measurement.

Further, when the crystal phase of the obtained SiC / Si—Al composite material was examined by X-ray diffraction, formation of aluminum carbide was not observed. Further, when the produced SiC / Si—Al composite material was left in high humidity (85%) for 30 days and then the crystal phase was examined again by X-ray diffraction, no change was observed. Further, a 3 × 4 × 20 mm test piece was cut out from the produced SiC / Si—Al composite material, and the thermal expansion coefficient was measured by TMA8140 manufactured by Rigaku Corporation. As a result, the thermal expansion coefficient was almost the same as AlN 5.1 ×. 10 ⁻⁶ / ° C.

(Example 2)
SiC powder (# 400 manufactured by Shinano Denki Seiki Co., Ltd., average particle size 30 μm): 100% by mass, phenol resin: 10% by mass (5% by mass in terms of carbon) as an organic binder, and 200 × 200 by press molding. A 30 mm rectangular parallelepiped shape was formed. The molded body was heated at 1000 ° C. for 3 hours in an Ar atmosphere to obtain a SiC preform.

A predetermined amount of solid Al is contained in a carbon sheet container, and a separately prepared 100 × 100 × 30 mm preform (the manufacturing method is the same as the above 200 × 200 × 30 mm preform) is placed under this container Except for this, a SiC / Si—Al composite material was obtained in the same manner as in Example 1 described above. However, in Example 2, the mass ratio of solid Al to solid Si was set to 25% by mass: 75% by mass. In the obtained SiC / Si—Al composite material, formation of aluminum carbide was not observed, and the thermal expansion coefficient was 5.1 × 10 ⁻⁶ / ° C. as in Example 1. In Example 2, since the preform was produced by the same method as in Example 1, the filling rate of SiC in the SiC / Si-Al composite material according to Example 2 was also 50% by volume.

(Example 3)
The SiC powder having an average particle diameter of 12 μm was used, and the SiC / SiC powder was obtained in the same manner as in Example 1 except that the mass ratio of solid Al to solid Si was 0.5 mass%: 99.5 mass%. A Si-Al composite material was produced. The thermal expansion coefficient was 2.7 × 10 ⁻⁶ / ° C., and the SiC filling rate was 40%.

(Comparative example)
A SiC / Si-Al composite material was produced in the same manner as in Example 1 except that solid Al was not placed in a carbon sheet-made container but was brought into contact with the preform together with solid Si and placed in the furnace. . However, in the SiC / Si-Al composite material according to this comparative example, generation of aluminum carbide was observed by X-ray diffraction.

  The present invention is suitable as a package material for housing a semiconductor chip or a heat dissipation material.

The figure which shows typically the manufacturing process of the SiC / Si-Al composite material which concerns on this invention. The figure which shows the another furnace arrangement | positioning aspect of the material for manufacturing the SiC / Si-Al composite material which concerns on this invention.

Explanation of symbols

10; Preform 10a; SiC / Si composite 11; Container (molten Al impermeable)
11a; container (molten Al permeability)
12; Solid Al
12a; Molten Al
13; Solid Si
13a; Molten Si
14; Outer frame container 15; Preform

Claims (3)

A method for producing a metal-ceramic composite material in which one or both of SiC powder and SiC fiber are dispersed in a Si-Al alloy matrix,
Providing a preform including any one or both of SiC powder and SiC fiber, and one or both of an organic binder and a carbon material;
Storing solid Al in a container that is impermeable to molten Al and permeable by reacting with molten Si, and placing the container, the preform, and solid Si in a furnace;
Heating the inside of the furnace to a temperature exceeding the melting point of Si,
In the heating step, molten Si generated by melting the solid Si is infiltrated into the preform to obtain a SiC / Si composite material, and then the molten Si is infiltrated into the container to melt the container with Al. By allowing the molten Al formed by melting the solid Al in the container to flow out of the container, the molten Al is interdiffused with the molten Si in the SiC / Si composite material. A method for producing a metal-ceramic composite material.   The said container containing solid Al is installed on the preform different from a product containing a SiC powder and / or both of a SiC fiber, and an organic binder. A method for producing a metal-ceramic composite material. Either or both of the filling rate of SiC and the Al content in the Si—Al alloy so that the thermal expansion coefficient is 2.7 × 10 ⁻⁶ / ° C. or more and 17.4 × 10 ⁻⁶ / ° C. or less. It adjusts, The manufacturing method of the metal-ceramics composite material of Claim 1 or Claim 2 characterized by the above-mentioned.

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