JPS6148542A - Fiber reinforced copper type composite material - Google Patents

Abstract

PURPOSE:To provide superior thermal and electrical characteristics by combining a copper-base matrix part with a fibrous part consisting essentially of whiskers or short fibers of TiB2 or TiN distributed in all directions and having specified electric conductivity and a specified coefft. of thermal expansion. CONSTITUTION:A fiber reinforced copper type composite material is composed of a fibrous part and a copper-base matrix part filling the gap among the fibers in the fibrous part. The fibrous part consists essensially of whiskers or short fibers of TiB2 or TiN distributed in all directions and having >=4X10<5>S/cm, especially >=10<3>S/cm electric conductivity, <=15X10<-6>/ deg.C, especially <=6X10<-6>/ deg.C coefft. of thermal expansion, and 20-1,000 aspect ratio.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a fiber-reinforced metal in which 411If1 is arranged in a copper-based matrix, and the fiber-reinforced copper can be used as an electrode material such as a supporting electrode of a semiconductor element. This relates to composite materials.

[Prior Art] In recent years, a new material that is a composite of an Il miscellaneous material and a metal matrix has been developed, and applied research is being conducted in various fields. One of these is a copper-carbon fiber composite material that combines carbon fiber and copper. This material makes good use of the low thermal expansion of carbon and the high electrical conductivity and high thermal conductivity of copper, and is used as an electrode material for supporting electrodes of semiconductor devices. In this case, the carbon mat has a low conductivity, so the arrangement method etc. is devised, for example, carbon fiber is used in a net shape, or
There is a method of arranging them in a spiral shape as a woven fabric as seen in No. 8554. FIG. 2 shows a perspective view of the composite material made in this way. This composite material has a structure in which a woven fabric 4 made of carbon fibers is spirally wound around a center #i13, and the space between the carbon fibers is filled with copper as a matrix material. Therefore, in the direction of the center line 3, the effect of copper acts to maintain high electrical conductivity and high thermal conductivity, and in the direction perpendicular to the center line 3, the effect of carbon fiber acts to keep thermal expansion low, and the semiconductor element This is preferable as an electrode.

Another method, as disclosed in Japanese Patent Application Laid-Open No. 57-185942, is to plate carbon fibers with copper, add metal powder having a higher melting point than the matrix, and then sinter the fibers. This method is a preferred method because it yields a copper-carbon fiber composite material that has low thermal expansion and isotropic physical properties such as thermal conductivity and electrical conductivity, and mechanical properties such as strength and hardness.

[Problems to be Solved by the Invention] In recent years, the density of semiconductor devices has increased, and the problem of generated heat has become widespread in various fields. Especially the electrode material!
A material with high electrical conductivity, high thermal conductivity, and a low coefficient of thermal expansion is desired. However, conventional copper-carbon fiber composite materials have the disadvantage that when the carbon fiber content m is increased to lower the coefficient of thermal expansion, the electrical conductivity and thermal conductivity decrease.
Furthermore, when the carbon fiber is made into a woven fabric and has a spiral structure, 411 ft of carbon fiber are laminated, so there is a risk of peeling at the laminated interface due to repeated thermal stress or processing such as cutting. there were. Moreover, in the case of this spiral-shaped structure, various performances are anisotropic, and there are restrictions on the direction in which the composite material is placed during use.

As a result of intensive research in view of the above problems, the present inventor came up with the idea of solving the above problems by devising the material and arrangement of the fiber portion, and completed the present invention. That is, an object of the present invention is to provide a fiber-reinforced copper-based composite material that has high electrical conductivity, high thermal conductivity, a low coefficient of thermal expansion, and isotropic properties.

[Means for solving the problem] The present invention provides a fiber-reinforced copper-based composite material composed of a fiber portion and a copper-based matrix portion that fills the space between the fibers of the fiber portion, in which the fiber portion is mainly made of Ti32. Alternatively, it is composed of TiN whiskers or short fibers, and the fiber portions are distributed non-oriented throughout, and the electrical conductivity is 4X10SS/cm.
and a thermal expansion coefficient of 15X10-6/'C or less.

I of the present invention! The fiber material used in the fiber-reinforced copper-based composite material is a material with high electrical conductivity, high thermal conductivity, and low coefficient of thermal expansion, and specifically, a material with electrical conductivity of 1038/am or more,
Thermal conductivity is 0.3w/cm-℃ or higher, thermal expansion coefficient is 6X1
It is necessary to have a property of 0-"/℃ or less. Examples of such materials include Ti, Ti, TiN, Tie, and Si.
Among them, it is desirable to use TiBz or TIN, which has a particularly high vI conductivity. Table 1 shows the characteristic values of TiB2 whiskers, TtN whiskers, and carbon fibers. From this table, the thermal conductivity and thermal expansion coefficient of TiB2 whisker and TAN whisker are carbon III.
It can be seen that although the conductivity is almost the same as that of ll, the conductivity is significantly higher. For this reason, the fiber-reinforced copper-based composite material of the present invention has taiI consisting of at least TlB2 or TtN.
It is preferable to use ll for the first expression. The best performance is obtained when TiB2 or TiN is used alone, but if such performance is not required, other materials such as liC, SiC, Z
A mixture of rC, carbon, etc. can also be used.

A feature of the present invention is that whiskers or short fibers made of the above-mentioned highly conductive material are used as the fibers constituting the fiber portion. The whiskers or short fibers have a diameter of 0.1μ to 1μ and an aspect ratio of 20 to 10.
A value in the range of 00 is desirable. Aspect ratio is 1000
If it is larger, that is, if the length is extremely good compared to the diameter of II miscellaneous, the distribution of m strings is likely to be uneven.
The properties of the obtained m-fiber reinforced copper-based composite material become anisotropic, which is undesirable. On the other hand, when the aspect ratio is smaller than 20, that is, when the length is extremely short compared to the diameter of 4 g, the fibers are not uniformly distributed, but the thermal expansion of the resulting fiber-reinforced copper-based composite material is This is not desirable as there is a problem that the rate does not decrease as much as expected. By using whiskers or short fibers having an aspect ratio within the above range, the distribution becomes uniform and non-oriented, resulting in isotropic performance.
A fiber-reinforced copper-based composite material having the same bending properties and properties when viewed from any direction can be obtained. The whiskers made of the highly conductive material may be manufactured by any of the common whisker manufacturing methods, such as an in-phase method, a liquid phase method, and a gas phase method.

Copper or a copper alloy can be used as a matrix for the fiber-reinforced copper-based composite material of the present invention. This matrix and the above-mentioned W4 sleeve are combined, and the blending ratio can be changed depending on the required performance. That is, as the number of M&fiber parts increases, the coefficient of thermal expansion decreases, which is preferable, but on the other hand, the electrical conductivity and thermal conductivity decrease, and as the number of matrix parts increases, the opposite phenomenon occurs.

Next, a method for producing the m-fiber reinforced copper-based composite material of the present invention will be explained.

A powder metallurgy method and a molten metal forging method can be used as a method for manufacturing the fiber-reinforced copper-based composite material of the present invention. As a powder metallurgy method, for example, copper powder with an appropriate particle size and whiskers such as TiB2 are wet mixed, dried, and then placed in a mold.
There is a method of pressure sintering at ℃ for about 1 hour. Further, when using the molten metal forging method, whiskers such as TiBz are first placed in a mold and pressurized to obtain a preformed body. After that, the preformed body heated to an appropriate temperature was placed in another mold, and the
Molten copper at about 0° C. to 1300° C. is injected and impregnated into the molded body using a plunger or gas pressure at a pressure of 500 ko/cm 2 or more. At this time, care must be taken because if the pressure is lower than 500 kg/Cm2, defects such as shrinkage cavities will remain in the composite material, which will adversely affect the properties.

Among the above two manufacturing methods, it is preferable to use the molten metal forging method to obtain the fiber-reinforced copper-based composite material of the present invention.

The reason for this is that powder metallurgy may leave pores in the composite material without adversely affecting the properties.

[Function] The fiber-reinforced copper-based composite material of the present invention has isotropic properties because the whiskers or short fibers constituting the fiber portion are uniformly distributed throughout and in random directions. In other words, the same results are given no matter which direction each characteristic is measured.

Furthermore, since the whiskers or short fibers are composed of a highly conductive substance, the conductivity remains at a high level even if the content of the whiskers or short fibers is increased to lower the coefficient of thermal expansion.

[Example] This will be explained below using examples.

(Example 1) TiBz whiskers with a diameter of 0.1 to 1μ and a length of 20 to 100μ obtained by a vapor phase method were used as the fiber part, copper was used as the matrix, and the ratio of the fiber part to the matrix part was adjusted to that of the fiber. Content rate is 5vo up to 10vo1% to 4Qvo 1%
Seven types of fiber-reinforced copper-based composite materials were manufactured by the molten metal forging method in increments of 1% to form Example 1.

First, T+B2 whiskers were placed in a mold with m required and pressed with a -axis press to obtain a preform. After that 800-1100
The preform heated to ℃ was placed in another mold and heated to 1200℃.
Molten copper at ~1300'C was injected, copper was impregnated between the fibers at a pressure of 500 kQ/cm2 using a plunger method, and the material was cooled to obtain a rectangular parallelepiped-shaped fiber-reinforced copper-based composite material of 30 mrn x 15 mm x 5 mm. . Obtained w4
A perspective view of the N-reinforced copper-based composite material is shown in Figure 1.

The electrical conductivity, thermal conductivity, and coefficient of thermal expansion of the above seven types of fiber-reinforced copper-based composite materials were measured, and the results are shown in FIGS. 3 and 4. These measurements were performed in each direction of the fiber-reinforced copper-based composite material, and almost the same results were obtained in all directions.

This means that the performance is isotropic, and it can be confirmed that the Ti321JH fibers are almost non-oriented.

(Example 2) Diameter 0.1-1μ and length 20-10 obtained by gas phase method
Example 2 was prepared by manufacturing seven types of 41-fiber-reinforced copper-based composite materials having the same shape as in Example 1 in exactly the same manner as in Example 1 except that TiN whiskers of 0 μm were used. The electrical conductivity, thermal conductivity, and coefficient of thermal expansion of these 41 fiber-reinforced copper-based composite materials were measured in the same manner as in Example 1, and the results are shown in FIGS. 5 and 6. It was confirmed that these fiber-reinforced copper-based composite materials had isotropic properties as in Example 1, and that the TiN fibers were almost non-oriented.

(Conventional Example) Carbon fibers with a diameter of 7 to 8 μm are made into a woven fabric, wound into a spiral shape, placed in a mold, and molten copper at 1200 to 1300°C is injected, using a plunger pressurization method to produce 500 kg/cm2.
Copper was impregnated into the fibers at a pressure of j and cooled to obtain a cylindrical fiber-reinforced copper-based composite material with a diameter of 20 rTl ff+ and a height of 10 mrn. In this conventional fiber-reinforced copper-based composite material, seven types of fiber-reinforced copper-based composite materials were prepared by changing the fiber content from 1Qvo1% to 40vo1% in 5vo1% increments, as in Example 1. manufactured.

The electrical conductivity, thermal conductivity, and coefficient of thermal expansion of the above seven types of conventional fiber-reinforced copper composite materials were measured, and the results are shown in Figures 3 to 3.
It is shown in FIG. Note that the electrical conductivity and thermal conductivity were measured in the height direction of the cylinder, and the thermal expansion coefficient was measured in the diameter direction of the cylinder.

From FIG. 4 and FIG. 6, it can be said that the thermal expansion coefficients of Example 1 and Example 2 are slightly higher than that of the conventional example, and that there is no difference in practical use and that they have almost the same characteristics.

From FIG. 3 and FIG. 5, it can be seen that in terms of electrical conductivity and thermal conductivity, Examples 1 and 2 are clearly superior in electrical conductivity and thermal conductivity to the conventional example. By the way, as shown in Table 1, TiBz or 1-
Although the iN whisker has a smaller thermal conductivity than carbon fiber, the thermal conductivity of the fiber-reinforced copper-based composite material is lower than that of the conventional example in both Examples 1 and 2.
Table 3 (Thermal expansion coefficient: 9.bx 10-'/"G) This is thought to be due to the fact that

Next, from Figures 4 and 6, the coefficient of thermal expansion is 8.0X10-6/
℃ and 9.5X10-6/℃, the content of M&O in the example and the conventional example was determined, and the results of determining the electrical conductivity and thermal conductivity of each from FIG. 3 and FIG. Shown in Tables 2 and 3.

It is clear from the table above that the fiber-reinforced copper-based composite material of the example of the present invention has considerably higher electrical conductivity and thermal conductivity than the conventional fiber-reinforced copper-based composite material when the coefficient of thermal expansion is the same. ing. In addition, if we determine the case where the thermal expansion coefficient is lowered to 9.5X10-6/"C or 68.0X10-6/"C, the second
From Table and Table 3, the decrease in electrical conductivity and thermal conductivity was in Example 5.
Compared to ~9% in the conventional example, it is considerably more popular at 12~20%. That is, the present invention provides a tM fiber-reinforced copper-based composite material that has higher electrical conductivity, higher thermal conductivity, and a lower coefficient of thermal expansion than conventional materials.

[Effects of the Invention] When the fiber-reinforced copper-based composite material of the present invention is used for electrodes of semiconductor devices, etc., heat dissipates quickly and thermal expansion is small.
Since it is highly conductive, it has excellent thermal and electrical performance as well as excellent durability. Furthermore, M & navy blue are evenly distributed,
In addition, since the direction of the fibers is random and non-oriented, there is no problem of peeling on the laminated surface as in the conventional case even during processing such as repeated hot bathing or cutting.

[Brief explanation of drawings]

FIG. 1 is a conceptual perspective view of a fiber-reinforced copper-based composite material of the present invention, and FIG. 2 is a conceptual perspective view of a fiber-reinforced copper-based composite material manufactured by a conventional method. Figure 3, Figure 4,
5 and 6 are diagrams showing the characteristics of fiber-reinforced copper-based composite materials according to the embodiment of the present invention and conventional examples. Figures 4 and 6 are diagrams showing the relationship between the coefficient of thermal expansion and the 8M content. 1... TiBz whisker 2... Copper 3... Center line 4... Woven fabric

Claims (3)

[Claims] (1) In a fiber-reinforced copper-based composite material composed of a fiber part and a copper-based matrix part that fills between the fibers of the fiber part, the fiber part mainly consists of whiskers or short fibers of TiB_2 or TiN, and Fiber reinforcement characterized in that the fiber portion is distributed non-oriented throughout, and has an electrical conductivity of 4 x 10^5 S/cm or more and a thermal expansion coefficient of 15 x 10^-^6/°C or less. Copper-based composite material. (2) The fiber part has an electrical conductivity of 10^3S/cm or more, a thermal conductivity of 0.3w/cm・℃ or more, and a thermal expansion coefficient of 6×10
The fiber-reinforced copper-based composite material according to claim 1, characterized in that the temperature is ^-^6/°C or less. (3) The fiber-reinforced copper-based composite material according to claim 2, wherein the fiber portion has an aspect ratio in the range of 20 to 1000.