JP2717918B2 - Metal composite parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal composite component used in a semiconductor integrated circuit device, and more particularly to a substrate for mounting a semiconductor element in a package and radiating heat generated by the semiconductor element (hereinafter referred to as a heat radiation substrate). Metal composite parts suitable for use as

[0002]

2. Description of the Related Art Conventionally, as a heat-radiating substrate used in a semiconductor integrated circuit device, it has been required to cope with a heating operation in a fixing step of a semiconductor element and an increase in heat generation due to an increase in density and output of an integrated circuit. What has a high heat dissipation effect is demanded. In addition to the high heat radiation effect, the heat radiation substrate is provided with a semiconductor element material, for example, silicon (S
It is also required that the thermal expansion coefficient of i) and gallium arsenide (GaAs) be matched.

[0003] Generally, as a heat dissipation board used in a high power semiconductor device, there is one described in Japanese Patent Application Laid-Open No. 2-102551. Here, the thermal expansion coefficient of the heat dissipation substrate is determined by using a semiconductor material such as Si forming a semiconductor integrated circuit,
In order to approach the thermal expansion coefficient of a ceramic substrate for mounting semiconductors (such as Al ₂ O ₃ ), a composite material in which molybdenum (Mo) is used as a base material and both sides of the base material are coated with copper (Cu) or a Cu alloy is used. Proposed.

On the other hand, recently, there has been an increasing demand for weight reduction of semiconductor integrated circuit devices. As described above, in a semiconductor integrated circuit device which emphasizes weight reduction, not only a substrate supporting the semiconductor integrated circuit but also a heat dissipation substrate is strongly required to be light, and a large thermal expansion coefficient is required as compared with a semiconductor material. There is also a tendency for the heat radiation substrate to be allowed.

[0005]

In order to meet such a demand, a heat-radiating substrate is made of a material having a relatively low density, that is, a material having a relatively low density.
Although it is necessary to be made of a light material, a low-density material, for example, aluminum (Al) generally has a thermal expansion coefficient that is too high as compared with a semiconductor material such as Si. Is not within the allowable range.

[0006] Even if the heat-dissipating substrate used in the high-power semiconductor device described above is applied to a semiconductor integrated circuit device that requires a reduction in weight, there are problems in terms of weight reduction, thermal expansion coefficient, and adhesion strength. there were.

According to experiments by the present inventors, Al having a thermal expansion coefficient of 23.0 × 10 ⁻⁶ / K or more is required to meet the demand for weight reduction. Although it is unsuitable in terms of surface, if the coefficient of thermal expansion is about ^{10.times.10.sup.-6} / K, a heat dissipation board that can withstand sufficient use is obtained.

An object of the present invention is to provide a metal composite component which can meet the demand for weight reduction and has a sufficient thermal expansion coefficient and thermal conductivity, and a method for producing the same.

[0009]

According to the present invention, there is provided a metal composite component comprising at least one base material and at least one bonding material joined to the base material, wherein the base material is , Molybdenum or an aluminum / silicon alloy, and the bonding material is at least one selected from stainless steel, invar, inconel, and titanium when the base material is molybdenum. If the substrate is an aluminum / silicon alloy, it is at least one selected from copper, aluminum, stainless steel, invar, inconel, and titanium, and the substrate and the composite crimping process or brazing process are joined by a process comprising the thermal expansion coefficient of the entire composite part is 10.0 × 10 ^-6 / greater than K 23.0 × 1 There range smaller than ^-6 / K, and wherein the layer thickness ratio defined by (thickness of layer thickness / the base material of the cladding material) is 3/1 to 9/1 A metal composite part is obtained.

According to the present invention, the thermal expansion coefficient is 1
The metal composite component having a ratio of 3.0 × 10 ⁻⁶ / K to 15.0 × 10 ⁻⁶ / K is obtained.

According to the present invention, there is further provided the metal composite component having a plating layer on a surface of the composite material. According to the present invention, the metal composite component having a plating layer on a boundary surface between the base material and the composite material is obtained.

It is to be noted that Mo is used for the base material having a lower thermal expansion coefficient and Al alloy is used for the base material having a higher thermal expansion coefficient. Increasing degrees.

In addition, the above-mentioned composite material is selected from a metal material which is lightweight and has good thermal conductivity. Except for these conditions, it is expected to improve brazing properties and corrosion resistance by applying a plating layer. It is limited to those that can be expected to improve the oxidation resistance and chemical resistance of the composite material itself. The former is Cu, A
l, the latter being stainless steel, invar, inconel,
It is titanium.

Further, as described above, by performing the rolling step after the explosion pressure bonding step, the layer ratio and the outer surface are adjusted to improve the bonding strength and the surface smoothness.

Further, as described above, when the brazing step and the rolling step are performed, the base material and the composite material having the layer thickness ratio designed by the brazing step are joined at 100 to 400 ° C., and then the rolling is performed. The outer surface is thereby adjusted. This facilitates plating or joining with a semiconductor integrated circuit. According to this method, the layer thickness ratio is greatly increased, for example, Cu / Mo = 1/1 to 2
/ 1 can be increased to about Cu / Mo = 3/1 to 9/1. Moreover, when rolling is performed, a high-quality and stable metal composite component (clad material) can be obtained.

Further, if the layer thickness ratio becomes large, there may be a case where even if the layer is heated, the stability at the time of bonding remains uneasy.
In this case, in the brazing step, a proper bonding temperature between the base material and the composite material is lowered, and a thin layer (plating layer) having good wettability is assisted in order to maintain and improve the adhesion. Intermediate as a layer.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A metal composite part according to an embodiment of the present invention will be described below along with its manufacturing process.

Example 1 A substrate material having a thickness of 0.2
Prepare a 1.5mm thick Mo plate and add 1.5mm
Was prepared. Placing a mating material on both sides of the base material, that is, positioning it in a three-layer form of Cu / Mo / Cu,
They were joined by an explosion pressure bonding method.

Next, the joined body was processed to a thickness of 2.0 mm by rolling, and three layers of Cu / Mo / Cu were formed.
The composite material was adjusted to have a layer thickness ratio of 7: 1: 7. In the final rolling step, particularly, cold rolling is performed to reduce the surface roughness to Rmax.2.
μm. The composite material thus joined is heat-treated at 800 ° C. for 30 minutes to remove the distortion.

This composite material is a so-called composite clad material of 94 wt% Cu-Mo. When the thermal characteristics were actually measured, the thermal expansion coefficient was 15.3 × 10 ⁻⁶ / K and the thermal conductivity was 0.80 cal / cm · sec · ° C. Moreover,
The density was 8.95 g / cm ³ .

When the semiconductor integrated circuit is mounted on the heat dissipation substrate, the mounting surface to which the semiconductor element is bonded is set to a value as close as possible to the coefficient of thermal expansion of the semiconductor element (a value having a relatively low coefficient of thermal expansion). On the other hand, there is a case where it is desired to give priority to heat conduction on the heat radiation side opposite to the mounting surface. In this case, the mounting surface is made Mo and the heat radiation surface is made Cu.
A combination of two layers of Cu is suitable. This configuration can also be easily manufactured by explosive pressure bonding. The joining material of this two-layer joining was rolled and finished to obtain good results with a surface roughness of Rmax.5 μm or less.

Example 2 A substrate material having a thickness of 1.0 mm
Prepare Mo plate of thickness 3.50m as material for composite material
m Cu plate was prepared. And 3 of Mo / Cu / Mo
They were positioned so as to form a layer and were joined by an explosion pressure bonding method.

Next, the joined body was processed to a thickness of 5.3 mm by rolling, and three layers of Mo / Cu / Mo were formed.
The composite material was adjusted to have a layer thickness ratio of 1: 3.3: 1. In the final rolling step, cold rolling is performed to reduce the surface roughness to Rmax.
The thickness was 5 μm. The composite material thus joined is heated to 850 ° C.
For 25 minutes to remove distortion.

This composite material has a Cu content of 59.1 wt% -Mo.
Is a so-called composite clad material. When the thermal characteristics were measured, the thermal expansion coefficient was 10.27 × 10 ⁻⁶ / K and the thermal conductivity was 0.70 cal / cm · sec · ° C. Moreover, the density was 9.41 g / cm ³ .

In the second embodiment, basically, the same thermal characteristics as those in the first embodiment are aimed. However, since Mo having a relatively high rigidity is arranged on the outer surface, the assembling is performed. Since Mo has a thermal expansion coefficient close to that of a semiconductor element, it is expected that Mo has a thermal expansion coefficient close to that of a semiconductor element, and thus, it is possible to reduce anxiety of peeling due to a difference in expansion in a direction parallel to a lamination direction of each layer in the composite clad material. In addition, a brazing material such as solder and a plating layer are relatively easily formed, and are excellent in compatibility with these steps.

Example 3 The thickness of the substrate material was 0.1
mm Mo plate is prepared and 3mm thick
Was prepared. The outer surface of Al of the composite material is acid-cleaned, and then the outer surface is coated with a thickness of 5 mm by a general zinc displacement method.
The μm is plated with nickel (Ni). On the other hand, the surface of Mo of the base material is subjected to electrolytic Ni plating to have a thickness of 3 μm.
A Ni layer was formed on m.

Next, 3% by 40% Sn-Pb solder
Brazing (joining) was performed at 00 ° C. to obtain a desired clad composite material of Al / Mo / Al.

When the thermal properties of this composite material were measured, it had a thermal expansion coefficient of 22.4 × 10 ⁻⁶ / K, which was lower than that of Al alone, and a thermal conductivity of 0.55 cal / cm · sec · ° C
And Al had better thermal conductivity than Al alone. Incidentally, the density of this composite material was 2.8 g / cm ³ . That is, it is understood that the metal composite part according to Example 3 has an extremely lightweight and high coefficient of thermal expansion, and is also superior in thermal conductivity to Al.

In addition, when this material is cold-rolled as it is to reduce the total thickness, Al is preferentially worked, so that the Al / Mo ratio can be easily changed within a range where the plating layer does not crack. That is, it is sufficient to join in a relatively thick state, not in a thin material state that is troublesome to handle,
The trouble of the manufacturing process and the defective product rate can be suppressed.

In the case where Cu is to be plated on Mo using a combination material, electrolytic Cu plating may be performed after Ni strike processing.

Example 4 In Example 4, a metal composite part is manufactured in consideration of chemical resistance and oxidation resistance. In this case, stainless steel (for example, SUS304), Inconel, or the like can be used as the joining material. Here, a SUS304 plate material having a thickness of 0.2 mm is prepared. On the other hand, for the base material, Al-
Si alloy (for example, having a thermal expansion coefficient of 1
3.5 × 10 ⁻⁶ / K, thermal conductivity 0.30 cal / cm ·
sec. ° C., density 2.53 g / cm ³ , Hv110, trade name CMSH A40), thickness 1.6
mm plate material was prepared. The substrate was plated with 5 μm-wide wrapped Ni by the same zinc substitution method as in Example 3. Furthermore, as a method similar to the third embodiment, 40% Sn
-Pb solder at 300 ° C (joining), S
US304 / Al-Si alloy (CMSH A40) / SUS30
4 was obtained.

The thermal characteristics include a thermal expansion coefficient of 18.9.
× 10 ⁻⁶ / K, thermal conductivity 0.54 cal / cm · sec
-The temperature and the density are 3.60 g / cm ³ , which is equivalent to that of alumina, and the material is excellent in corrosion resistance and oxidation resistance of the surface layer.

Example 5 As a substrate, a thickness of 0.2 mm
Mo plate is prepared, and pure Al with a thickness of 10 mm is used as a bonding material.
A board was prepared.

The Mo plate was coated with 2 μm of Ni by electrolytic Ni plating, and heat-treated at 800 ° C. in a hydrogen stream to sufficiently improve the density strength of Mo / Ni. Al plate is
By the same zinc substitution method as in Example 3, Ni was wrapped and plated at 2 μm.

After this was superposed to form a three-layered structure of Mo / Al / Mo, a working rate of about 60% in terms of total thickness was applied by hot rolling at a heating temperature of 400 ° C. As a result, a clad composite material having a Mo part of 0.18 mm and an Al part of 4 mm was obtained.

The composite material thus obtained has a coefficient of thermal expansion of 13.2 × 10 ⁻⁶ / K and a thermal conductivity of 0.24 cal / c.
m · sec · ° C. and density 3.0 g / cm ³ .
Further, in this composite material, Mo is located in the first layer on the surface and sandwiches the base material, so that it can be applied to a composite material requiring high strength.

Further, even if Al is not plated, Mo is coated with the strong Ni of the present example as required, and then joined by removing the oxide layer of the Al surface layer by explosion pressure bonding and finishing by rolling. By applying the same, it is possible to obtain a composite material having a three-layer configuration equivalent to that of the above-described embodiment.

It was also confirmed that the clad composite materials according to the above-described embodiments all achieved a desired level of adhesion strength at the bonding interface, and could be used as a substrate having stable performance.

In this way, by taking into account the substantial weight reduction and thermal characteristics of the heat dissipation substrate, it is incorporated into a package as a clad metal composite component, and satisfies different specifications depending on each design situation in the market. Things can now be obtained.

In the metal composite component according to the present invention described above, in addition to the heat dissipation board for the ceramic package, the peripheral components such as the lead frame have a high thermal expansion, and the thermal compatibility with the material is emphasized. It can be applied to members that need to respond to joining where importance is placed on weight especially as the use of plastic packages progresses. This is useful in designing a package.

[0041]

As described above, the metal composite part according to the present invention can meet the demand for weight reduction and has sufficient characteristics in terms of thermal expansion coefficient and thermal conductivity.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication location H01L 23/373 (72) Inventor Tadashi Arikawa 2nd Iwase Koshimachi, Toyama City, Toyama Pref. Tokyo Tungsten Co., Ltd. Inside the Toyama Works (72) Inventor Yasuhiro Ujimoto 5447 Oji Yamaji, Chikushino-shi, Fukuoka Asahi Kasei Kogyo Co., Ltd. (72) Inventor Satoshi Kobayashi 1-1, Uchisaiwai-cho, Chiyoda-ku, Tokyo Asahi Kasei Kogyo Co., Ltd. (56) References JP-A-1-118435 (JP, A) JP-A-63-261863 (JP, A) JP-A-2-187285 (JP, A) JP-A-64-36440 (JP, A)

Claims (4)

(57) [Claims] 1. A metal composite component comprising at least one substrate and at least one bonding material joined to the substrate, wherein the substrate comprises molybdenum and an aluminum / silicon alloy. When the base material is molybdenum , the bonding material is a stainless steel.
Steel, Invar, Inconel, and titanium.
At least one kind of base material, wherein the base material is aluminum /
In the case of silicon alloy, copper, aluminum, stainless steel
Steel, Invar, Inconel, and titanium.
The base material and the composite material are joined by a process including an explosion pressure bonding process or a brazing process, and the thermal expansion coefficient of the entire composite component is 10.0.
The layer thickness ratio is greater than × 10 ⁻⁶ / K and less than 23.0 × 10 ⁻⁶ / K , and the layer thickness ratio defined by (layer thickness of the composite material / layer thickness of the base material) A metal composite part having a ratio of 3/1 to 9/1. 2. The thermal expansion coefficient is 13.0 × 10 ⁻⁶ / K.
2. The metal composite part according to claim 1, wherein the ratio is 15.0 × 10 ⁻⁶ / K. 3. 3. The metal composite component according to claim 1, wherein a plating layer is provided on a surface of the composite material. 4. A plating layer is provided on a boundary surface between the base material and the bonding material in contact with the base material.
A metal composite part according to any one of the above.