JP2815689B2 - High-strength heat-radiating structural member for packaged semiconductor devices - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-radiating structural member such as a heat sink material or a substrate material in a package type semiconductor device, which is made of a high-strength Mo-based sintered alloy. It is.

[Conventional technology]

In general, as shown in a vertical sectional view of FIG. 1, a package type semiconductor device is provided with a large number of external leads 2 arranged in a lattice pattern on an upper surface of an alumina ceramic frame 1 so as to face upward. Formed on the bottom surface of the frame 1
Through a metallizing layer 5 formed by sintering powder or the like and a plating layer 6 such as a Ni plating layer further formed on the metallizing layer, the substrate material 3 on which the plating layer 6 is formed PGA having a structure in which a semiconductor element 4 is mounted on the upper surface of a substrate material 1 by brazing using a braze or the like.
(Pin grid array) As shown in the vertical sectional view in FIG. 2, a plurality of external leads 2 are horizontally arranged along the outer periphery of the alumina ceramic frame 1 to form a package. 1, the substrate material 3 is brazed through the metallizing layer 5 and the plating layer 6 in the same manner as in the apparatus of FIG. 1, and the heat sink material 7 on which the semiconductor element 4 is mounted is also interposed through the surface plating layer 6. A flat package type having a structure brazed on the upper surface of the substrate material 3 and, as shown in the vertical sectional view of FIG. 3, external leads are provided along the outer periphery of the bottomed alumina ceramic frame 1. 2, a heatsink material 7 on which the semiconductor element 4 is mounted via a metallizing layer 5 and a plating layer 6 is brazed on the bottom surface of the frame 1; In addition, the first to third In the apparatus described above, reference numeral 11 denotes a sealing cap, which is formed by cutting a part of the side wall of the metal frame 8 as shown in a plan view in FIG. 4 and a longitudinal sectional view in FIG. An alumina ceramic terminal 9 having a connection circuit 10 is provided in the recess 8a, and a substrate material 3 is provided on the bottom surface of the frame 8 through a metallizing layer 5 and a plating layer 6 such as a Ni plating layer. The external lead 2 is connected to the connection circuit 10 exposed to the outside of the connection circuit of the terminal 9 in an airtight manner, and the upper surface of the terminal 9 is sealed with a cap 11 for sealing. A metal package type in which a metal seal ring 12 is brazed, and further, as shown in a vertical sectional view in FIG. 6, made of a metal such as iron or Kovar (Fe-Ni-Co alloy). External lead 2 penetrated through base 13 to base 13 Then, a heat sink material 7 on which the semiconductor element 4 is mounted is brazed on the upper surface of the central portion of the base 13 via the plating layer 6, and the whole of A glass terminal package type having a structure hermetically surrounded by a cap 11 is known.

In these various package type semiconductor devices, the heat generated by the semiconductor element 4 is efficiently radiated to the outside through the substrate material 3 and the heat sink material 7 on which the semiconductor element 4 is mounted. Semiconductor element 4 by stress
Etc. are not damaged.

In addition, heat dissipation is required as a substrate material or heat sink material which is a heat dissipation structure member of these semiconductor devices.
In addition, since a low coefficient of thermal expansion is required for the purpose of preventing peeling, 1 to 30% by weight (hereinafter,% indicates% by weight) in a porous Mo sintered body as described in JP-B-63-27860. It is also well known that a material formed by infiltrating Cu) is used.

[Problems to be solved by the invention]

However, with the recent increase in the degree of integration of semiconductor devices, substrate materials and heat sink materials, which are heat dissipating structural members of semiconductor devices, are also required to be reduced in weight and thickness. There is a strong demand for the development of heat-radiating structural members having strength, but the heat-radiating structural members made of many other materials, including the above-mentioned conventional heat-radiating structural members, all have insufficient strength. At present, it is not possible to satisfy the demands of the above.

[Means for Solving the Problems] Accordingly, the present inventors have conducted research to develop a heat-radiating structural member of a semiconductor device having high strength from the above-described viewpoints. , Ni: 2 to 12%, Fe: 1.5 to 8%, and, if necessary, W: 2 to 12%, with the balance being Mo and having the composition of Mo and inevitable impurities. When composed of a sintered alloy, the resulting heat-radiating structural member has a heat-radiating property because it is made of an alloy, and has a thermal expansion coefficient of 3.5 to 4 × 10 ^-6 / ° C. Thermal expansion coefficient of As element: 5-6 × 10 ^-6 / ° C. Thermal expansion coefficient of alumina ceramic constituting frame, etc .: about 7 × 10 ^-6 /
It has a thermal expansion coefficient of 4.5 to 8.2 × 10 ^-6 / ° C, which is equivalent to ° C, so there is no occurrence of peeling or breakage between these structural members, and it is made of a porous Mo sintered body impregnated with Cu. Approximately 80 kg / m in tensile strength, higher than the above conventional heat dissipation structural members
The research results show that the material has a high strength of m ² or more and can be made thinner and lighter.

The present invention has been made based on the above research results, and the reason why the component composition of the Mo-based sintered alloy constituting the heat dissipation structural member is limited as described above will be described below.

(A) Ni and Fe These components combine with each other during sintering to form a liquid phase at 1430 ° C at the lowest temperature, thereby improving sinterability, thereby improving strength and elongation. It has the effect of increasing the density to a theoretical density ratio of 99.5% or more. However, if the content is less than 2% of Ni and less than 1.5% of Fe, respectively, the amount of liquid phase generated is insufficient, so the above effect is desired. When the contents exceed Ni: 12% and Fe: 8%, respectively, the coefficient of thermal expansion increases sharply, and it may peel off from the mating member or break it. Therefore, the content was determined to be Ni: 2 to 12% and Fe: 1.5 to 8%.

(B) WW component has an effect of further improving strength and elongation in the state of coexistence with Ni and Fe, so that it is contained as necessary, but even if its content is less than 2%, Even if the content exceeds 12%, a desired effect cannot be obtained in the above-mentioned action, so the content is set to 2 to 12%.

〔Example〕

Next, the structural member of the present invention will be specifically described with reference to examples.

As raw material powders, W powder, Ni powder, Fe powder, and Mo powder each having an average particle diameter in the range of 1 to 6 μm are prepared, and these raw material powders are blended in the blending composition shown in Table 1, After wet mixing in a ball mill for 72 hours, 1 ton / c
Pressing into a green compact with a pressure of m ²
By sintering at a predetermined temperature in the range of 1350 to 1400 ° C., it has substantially the same component composition as the blended composition, and a plane: 2
Structural member 1 of the present invention having dimensions of 5 mm x 25 mm and thickness of 1 mm
9 and comparative structural members 1 and 2 were manufactured.

The comparative structural members 1 and 2 both contain Ni and Fe, which are constituent components of the Mo-based sintered alloy. The amounts (marked with * in Table 1) are outside the scope of the invention.

Also, for comparison purposes, the average particle size as a raw material powder: 4.3μ
Using a Mo powder having a m of 3 m, three types of green compacts with different porosity were formed by changing the pressing pressure, and these green compacts were sintered at a temperature of 1400 ° C. A porous Mo sintered body having the porosity shown is formed and then
By performing Cu infiltration, conventional structural members 1 to 3 having the same dimensions of 25 mm × 25 mm in plane and 1 mm in thickness were manufactured.

Next, regarding the various structural members obtained as a result,
The theoretical density ratio, coefficient of thermal expansion (20 to 800 ° C.), tensile strength, elongation, and Vickers hardness (load: 10 kg) were measured. The measurement results are shown in Table 1.

[Effects of the Invention] From the results shown in Table 1, the structural members 1 to 9 of the present invention are shown.
All have a thermal expansion coefficient equivalent to that of the conventional structural members 1 to 3, and have a higher theoretical density ratio than this, and furthermore, it is clear that they show much higher tensile strength and elongation, and Ni And Comparative Example 1 in which the content of Fe and Fe is out of the range of the present invention, the desired high strength and high elongation cannot be obtained, and the content of Ni and Fe is high outside the range of the present invention. In No. 2, the coefficient of thermal expansion is increased.

As described above, the heat-radiating structural member of the present invention has a low coefficient of thermal expansion equivalent to that of a semiconductor element or various ceramic members constituting a semiconductor device. damage without having to also have a high strength and high elongation, the value tensile strength of about 80 kg / mm ² or more and to 8% or more in elongation, this is Ya substrate material is a heat radiation structural member The heat sink material and the like can be made thinner and lighter, and have industrially useful characteristics such as being able to sufficiently cope with high integration of semiconductor devices.

[Brief description of the drawings]

1 to 6 are views showing the structure of various package type semiconductor devices, wherein FIGS. 1 to 3 and FIGS.
FIG. 4 is a plan view of the device shown in FIG. 3 ... substrate material, 4 ... semiconductor element, 7 ... heat sink material.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takaharu Miyamoto Nagano Prefecture, Nagano City, Oita Kurita-sha Toshida 711 Shinko Electric Industry Co., Ltd. (72) Inventor Miyagawa Fumio Miyagawa, Nagano-shi, Nagano City, Oita Kurita-sha, 711 Toshida Shinko Inside Electric Industry Co., Ltd. (72) Inventor Toru Kono 1-297 Kitabukuro-cho, Omiya City, Saitama Prefecture Mitsubishi Metal Corporation Central Research Laboratory (58) Field surveyed (Int. Cl. ⁶ , DB name) C22C 27/04 102 H01L 23/14 H01L 23/36

Claims (2)

(57) [Claims] 1. A package comprising a Mo-based sintered alloy containing Ni: 2 to 12% and Fe: 1.5 to 8%, the balance being Mo (hereinafter referred to as "weight%") comprising Mo and unavoidable impurities. High-strength heat-radiating structural member for semiconductor devices. 2. A composition containing Ni: 2 to 12% and Fe: 1.5 to 8%, and W: 2 to 12%, with the balance being Mo and unavoidable impurities (hereinafter referred to as% by weight). High-strength heat-dissipating structural member of a packaged semiconductor device composed of a Mo-based sintered alloy having