Substrate material for mounting a semiconductor device, substrate for mounting a semiconductor device, semiconductor device, and method of producing the same

Inactive Publication Date: 2005-02-03
SUMITOMO ELECTRIC IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

A substrate having higher reliability can be formed by coating the surface of the material of the present invention with a plating layer, chromate film, or oxide film, or by forming on the surface thereof a layer of a metal having a Young's modulus of 15,000

Problems solved by technology

However, because of their low rigidity, the plastics are apt to deform when used in combination with materials having a high specific gravity, such as Cu—W alloys and Cu—Mo alloys, and this limits the use of these alloys as substrate materials in combination with plastic packages.
These techniques also have difficulties in application to substrate materials made of a Cu—W alloy or a Cu—Mo alloy, because the use of such heavy substrate materials may flatten the solder balls excessively.
In addition, the use of substrate materials made of these alloys is disadvantageous in cost because tungsten and molybdenum are relatively expensive metals.
However, these semiconductor substrate materials have the same problem as the Cu—W alloys or the like because Cu also has a density as high as 8.9 g/cm3.
However, substrate materials made of aluminum have problems that they can be used in only limited applications because aluminum has a thermal expansion coefficient as high as 23.5×10−6/° C., and that the substrates are apt to warp or deform because of their low rigidity.
However, there are increasing cases where the semiconductor substrate materials used in combination with plastic packages, having a poor thermal conductivity, are required to have a thermal conductivity of 180 W/m·K or higher when heat dissipation from the whole package is taken in account.
First, the casting method has a drawback that the deviation of composition which is caused during cooling is difficult to avoid.
This is because since the Al—SiC alloy produced by the casting method necessarily has a higher aluminum concentration in the surface part, the difference in silicon carbide concentration between the central and surface parts exceeds 1% by weight, making it impossible to obtain a material having a homogeneous composition.
It is also difficult to completely eliminate voids.
Although the pressure casting method is effective in eliminating most voids, the concentration of aluminum around the surface tends to be high due to the pressure applied.
It is hence difficult in the pressure casting method to reduce the difference in silicon carbide concentration between the central and surface parts to 1% by weight or smaller.
On the other hand, the impregnation method in which a preform of silicon carbide is impregnated with molten aluminum has a drawback that aluminum should be infiltrated in

Method used

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  • Substrate material for mounting a semiconductor device, substrate for mounting a semiconductor device, semiconductor device, and method of producing the same
  • Substrate material for mounting a semiconductor device, substrate for mounting a semiconductor device, semiconductor device, and method of producing the same
  • Substrate material for mounting a semiconductor device, substrate for mounting a semiconductor device, semiconductor device, and method of producing the same

Examples

Experimental program
Comparison scheme
Effect test

example 1

An aluminum powder having an average particle diameter of 25 μm was mixed in various proportions with a silicon carbide powder consisting of a mixture of α-crystals and β-crystals and having an average particle diameter of 50 μm to prepare sample powders 1 to 9 respectively having silicon carbide contents of 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, and 75% by weight. These sample powders each was homogenized with a kneader for 1 hour to obtain aluminum / silicon carbide starting powders.

The starting powders obtained were compacted at a pressure of 7 t / cm2 to obtain tablet test pieces having a diameter of 20 mm and a height of 30 mm. These compacts were sintered at 700° C. for 2 hours in a nitrogen atmosphere having a nitrogen concentration of 99% by volume or higher. As a results, aluminum / silicon carbide composite alloy sinters were obtained which retained the original shape of the compacted test pieces.

However, the alloy of sample 9 was not dense and had voids in a surface layer ...

example 2

An aluminum powder having an average particle diameter of 25 μm was mixed in a weight ratio of 1:1 with a silicon carbide powder consisting of a mixture of α-crystals and β-crystals and having an average particle diameter of 50 μm. This mixture was homogenized with a kneader for 1 hour to obtain an aluminum / silicon carbide starting powder. The starting powder obtained was compacted at a pressure of 7 t / cm2 to obtain tablet test pieces having a diameter of 20 mm and a height of 30 mm. These compacts were sintered in a nitrogen, hydrogen, or argon atmosphere under the conditions shown in Table 2. As a result, aluminum / silicon carbide composite alloy sinters were obtained which retained the original shape of the compacted test pieces.

Each sinter was examined for density, thermal conductivity, thermal expansion coefficient, nitrogen content, oxygen content, aluminum carbide content, and the ratio of the peak intensity for aluminum carbide (012) to that for aluminum (200) both determi...

example 3

Some of the aluminum / silicon carbide composite alloy sinters obtained as sample 6 in Example 1 were repressed at a pressure of 7 t / cm2 in a nitrogen atmosphere (sample 6-1). Part of the repressed sinters were sintered again at 700° C. for 2 hours in a nitrogen atmosphere (sample 6-2).

These sinter samples were examined for density, thermal conductivity, thermal expansion coefficient, nitrogen content, oxygen content, aluminum carbide content, and the ratio of the peak intensity for aluminum carbide (012) to that for aluminum (200) both determined by X-ray analysis with CuKα line, in the same manner as in Example 1. The results obtained are shown in Table 3. It is understood from Table 3 that repressing and resintering were effective in heightening the density and improving the thermal conductivity.

TABLE 3ThermalSinteringThermalexpansionNitrogenOxygenAl4C3Al4C3conditionsDensityconductivitycoefficientcontentcontentcontent(012) / Sample(° C. × h)(g / cm3)(W / m × K)(×10−6 ° C.)(wt %)(wt ...

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Abstract

To provide a substrate material made of an aluminum/silicon carbide composite alloy which has a thermal conductivity of 100 W/m×K or higher and a thermal expansion coefficient of 20×10−6/° C. or lower and is lightweight and compositionally homogeneous. A substrate material made of an aluminum/silicon carbide composite ally which comprises Al—SiC alloy composition parts and non alloy composition part and dispersed therein from 10 to 70% by weight silicon carbide particles, and in which the fluctuations of silicon carbide concentration in the Al—SiC alloy composition parts therein are within 1% by weight. The substrate material is produced by sintering a compact of an aluminum/silicon carbide starting powder at a temperature not lower than 600° C. in a non-oxidizing atmosphere.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate material for use as, e.g., a heat sink material in a semiconductor device, and also to a substrate, a semiconductor device, and method of producing the same. 2. Discription of the Prior Art With the recent remarkable increases of the processing rate of semiconductor device and the degree of integration in semiconductor device, the heat generated by semiconductor elements has come to produce influences that are not negligible. As a result, substrate materials for mounting semiconductor devices have come to be required to have a high thermal conductivity for efficiently removing the heat generated by semiconductor elements. Substrate materials are further required not to be deformed by a thermal stress at the interface between the substrate materials and other device members used in combination therewith. Hence, substrate materials are required not to have a large difference in ther...

Claims

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Application Information

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IPC IPC(8): B22F3/24C22C1/05C22C1/10C22C21/00C22C32/00C25D17/16H01L21/48H01L23/14H01L23/15
CPCC22C32/0063Y10T428/24975H01L23/15H01L2224/16H01L2224/32188H01L2224/48247H01L2224/73253H01L2924/01012H01L2924/01025H01L2924/01046H01L2924/01078H01L2924/01079H01L2924/09701H01L2924/15153H01L2924/15165H01L2924/1517H01L2924/15311H01L2924/15312H01L2924/1532H01L2924/16152H01L2924/16195H01L24/48H01L2924/01019H01L2924/01322H01L21/4807Y10T428/26Y10T428/252Y10T428/25H01L2224/73265H01L2224/32245H01L2224/73204H01L2224/48091H01L2224/32225H01L2224/16225H01L2924/00H01L2924/00014H01L2924/12042H01L2924/181Y10T428/31678H01L2224/45099H01L2224/05599H01L2224/85399H01L2224/45015H01L2924/207
InventorYAMAGATA, SHINICHIABE, YUGAKUIMAMURA, MAKOTOFUKUI, AKIRATAKANO, YOSHISHIGETAKIKAWA, TAKATOSHIHIROSE, YOSHIYUKI
OwnerSUMITOMO ELECTRIC IND LTD