KR101949694B1 - Heat sink plate - Google Patents

Abstract

The present invention relates to a heat dissipation plate material which can be suitably used for packaging a high output semiconductor device using a compound semiconductor and which has a thermal expansion coefficient equal to or similar to that of a ceramic material so as to allow good bonding even when bonded to a ceramic material such as alumina, To a heat sink material capable of obtaining a high thermal conductivity capable of rapidly discharging a large amount of heat generated in the device to the outside.
The heat sink material according to the present invention has a structure in which two or more kinds of materials are stacked and a first layer, a second layer, a third layer, a fourth layer and a fifth layer are sequentially stacked in the thickness direction of the heat sink material Wherein the second layer and the fourth layer are made of a material having a thermal expansion coefficient smaller than that of the first layer and the fifth layer, the third layer is composed of a first material layer and a second material layer, The material layer has a thermal expansion coefficient different from that of the first material layer and is formed to extend in contact with the second layer and the fourth layer in the thickness direction with a predetermined thickness inside the first material layer, , A partition wall structure in which the first material layer and the second material layer are alternately repeated in a plurality of directions along any one of a direction in which the length of the heat dissipation plate material is short (short axis direction) and a direction in which the length is long .

Description

HEAT SINK PLATE

The present invention relates to a heat sink material, and more particularly, to a heat sink material which can be suitably used for packaging a high-output semiconductor device using a compound semiconductor. Even when bonded to a ceramic material such as alumina (Al ₂ O ₃ ) To a heat sink material having a thermal expansion coefficient that is the same as or similar to that of a ceramic material, and at the same time a high thermal conductivity capable of quickly discharging a large amount of heat generated in a high output device to the outside.

Recently, high power amplification devices using GaN compound semiconductors have been attracting attention as key technologies in information communication and defense fields.

In such high output electronic devices and optical devices, much heat is generated compared with general devices, and a packaging technique capable of efficiently discharging a large amount of generated heat is needed.

At present, a high output semiconductor device utilizing a GaN type compound semiconductor includes a two-layer composite material of W / Cu, a two-phase composite material of Cu and Mo, a three-layer composite material of Cu / Cu-Mo alloy / 6) and a multi-layer composite material of Cu / Mo / Cu / Mo / Cu (see FIG. 7), a metal-based composite plate having relatively good thermal conductivity and low thermal expansion coefficient is used.

However, since the thermal conductivity of the composite sheet in the thickness direction is about 250 W / mK at maximum and it can not realize higher thermal conductivity than that, it is difficult to apply to a device such as a power transistor of several hundred watt class.

On the other hand, a brazing process with a ceramic material such as alumina (Al ₂ O ₃ ) is essential for the process of manufacturing a semiconductor device.

Since the brazing process is performed at a high temperature of about 800 ° C or more, the brazing or fracturing occurs in the brazing process due to the difference in thermal expansion coefficient between the metal composite substrate and the ceramic material. Causing a failure.

Furthermore, in recent years, in order to realize high output and increase production efficiency in manufacture, a plurality of chips are mounted on one heat sink material and the length of the package is getting longer. As the length of the package becomes longer, the length of the heat sink material becomes longer. As a result, the thermal expansion coefficient difference between the heat sink material and the semiconductor device, which is not problematic when mounting one chip, The similarity of the thermal expansion coefficient of the ceramic material becomes more important as a heat sink material used for mounting a plurality of chips.

Korea Patent Publication No. 2015-0133312

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the above-described conventional techniques, and has a low thermal expansion coefficient of 9.0 × 10 ^-6 / K or less in the plane direction (particularly, It is possible to realize a high thermal conductivity of 270 W / mK or more in the thickness direction of the plate material as well as no warping or breakage due to a difference in thermal deformation amount, and in particular, Which can be suitably used for applications in which a heat sink is used.

According to an aspect of the present invention, there is provided a heat sink material having a structure in which two or more kinds of materials are laminated, wherein a first layer, a second layer, a third layer, a fourth layer, Wherein the second layer and the fourth layer are made of a material having a coefficient of thermal expansion lower than that of the first layer and the fifth layer, and the third layer is formed of a first material layer and a second material layer Wherein the second material layer has a thermal expansion coefficient different from that of the first material layer and is formed so as to be in contact with the second and fourth layers in the thickness direction with a predetermined thickness inside the first material layer , A plurality of first material layers and a plurality of second material layers are formed on one surface of the heat dissipation plate material in a direction in which the length of the heat dissipation plate material is short (short axis direction) and a long direction The present invention provides a heat dissipating plate having an alternating barrier rib structure.

The heat radiating plate according to the present invention can have a thermal conductivity of 270 W / mK or more, preferably 300 W / mK or more in the thickness direction of the plate material, and can be suitably used for high output devices.

Heat-radiating plate according to the present invention is the thermal expansion coefficient of the long axis ^{8.0 × 10 -6 / K ~ 9.0} × 10 -6 / difference in thermal expansion coefficient of the high-power element K consisting of a heat sink material and the brazing of ceramic material is larger It is possible to prevent warping or peeling or breakage of the ceramic in the process of performing the brazing process to package two or more devices.

FIG. 1 shows a longitudinal axis direction and a minor axis direction in a thickness direction and a plane direction of the heat radiation plate according to the present invention.
2 schematically shows the structure of a heat radiating plate according to an embodiment of the present invention.
3 is a schematic view illustrating a process of manufacturing a heat radiating plate according to an embodiment of the present invention.
FIG. 4 is an image of a heat radiating plate manufactured according to an embodiment of the present invention, taken along a section in the short axis direction of FIG. 1;
FIG. 5 is an image of a heat radiating plate manufactured according to an embodiment of the present invention, taken along a longitudinal section of FIG. 1; FIG.
6 is a cross-sectional view of a heat sink material having a Cu-CuMo alloy-Cu laminate structure (the thickness of the CuMo alloy layer is 80% of the total thickness) as Comparative Example 1;
7 is a cross-sectional view of a heat sink material having a Cu-Mo-Cu-Mo-Cu laminated structure (Mo layer thickness is 10.5% of the total thickness) as Comparative Example 2;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the following embodiments. Embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art.

The present inventors have found that a heat sink material having a low coefficient of thermal expansion of not more than 9.0 × 10 ^-6 / K in the plane direction (particularly, in the major axis direction) of the plate material and a high thermal conductivity of 270 W / mK or more in the thickness direction of the plate material The present inventors have found that the longitudinal thermal expansion coefficient and the thermal conductivity in the thickness direction of the sheet material can be realized through the heat sink material having the following structure,

Fig. 1 shows the structure of the heat radiating plate according to the present invention and the thickness direction and the plane direction (long axis and short axis) defined in the present invention.

As shown in FIG. 1, the heat sink material according to the present invention has a structure in which a first layer, a second layer, a third layer, a fourth layer and a fifth layer are sequentially laminated in the thickness direction of the plate material, The second layer and the fourth layer are made of a material having a coefficient of thermal expansion smaller than that of the first layer and the fifth layer, the third layer is composed of a first material layer and a second material layer, Wherein the first heat radiating plate member has a thermal expansion coefficient different from that of the material layer and is formed to extend in contact with the second and fourth layers in a thickness direction with a predetermined thickness inside the first material layer, (Short axis direction) and a long direction (long axis direction).

In the heat sink material according to the present invention, the second layer and the fourth layer made of a material having a lower thermal conductivity and a smaller thermal expansion coefficient than the first and fifth layers are disposed, and the thermal conductivity A plurality of second material layers having a low degree of thermal expansion and a small coefficient of thermal expansion are vertically arranged.

This makes it possible to maintain the thermal expansion coefficient of the heat sink material in the major axis direction at a low level and to allow the heat transfer in the thickness direction of the third layer to proceed through the relatively good thermal conductivity layer, , Long axis direction) can be adjusted to be similar to that of the ceramic material, so that even if two or more elements are bonded in the major axis direction, the difference in thermal deformation amount can be minimized, and peeling or breakage of the ceramic can be prevented.

On the other hand, the material layer preferably has a length in the direction of the longer length in the plane direction (the major axis direction) and can take the form of a partition along the direction (minor axis direction) in which the length is shorter in the plane direction.

In the heat sink material, the first layer, the third layer and the fifth layer may be made of a material including Cu. The first layer, the third layer and the fifth layer are preferably made of pure Cu having a Cu content of 99 wt% or more, considering the thermal conductivity characteristics in the thickness direction of the plate material.

In the heat sink material, the second layer and the fourth layer may be made of an alloy including Cu and Mo. At this time, the alloy preferably contains 30 to 60 wt% of Cu and 40 to 70 wt% of Mo. If the Cu content is less than 30 wt%, the coefficient of thermal expansion is too small to be 7 x 10 ^-6 / K or less, A brazing phenomenon occurs in the ceramic direction at the time of brazing, and when it exceeds 60% by weight, the thermal expansion coefficient is too high to be greater than 9 × 10 ^-6 / K to warp in the direction opposite to the ceramic. If the Mo content is less than 40% The thermal expansion coefficient is greater than 9 × 10 ^-6 / K, which causes the ceramic to warp in a direction opposite to that of the ceramic. When it exceeds 70% by weight, the coefficient of thermal expansion is too small, less than 7 × 10 ^-6 / K, This is because a bending phenomenon occurs.

If the thickness of the first layer and the fifth layer is less than 10% of the total thickness in the thickness direction of the heat sink member, the thermal expansion coefficient may be too low to cause warping. If the thickness exceeds 30%, the thermal expansion coefficient is too large It is preferable that the thickness is 10 to 30%, and it is preferable that the first layer and the fifth layer have substantially the same thickness.

When the thickness of the second layer and the fourth layer is less than 5% of the total thickness in the thickness direction of the heat sink member, the thickness of the heat sink member is too thin to cause deformation of the product. If the thickness exceeds 20% It is preferably 5 to 20%.

In the heat dissipation plate material, the second material layer may be made of pure Mo containing at least 99 wt% of Mo to adjust the coefficient of thermal expansion in the major axis direction.

If the sum of the volumes of the plurality of formed second material layers is less than 10% of the total volume of the third layer, it is difficult to maintain the coefficient of thermal expansion in the major axis direction at 8 to 9 × 10 ^-6 / K, It is difficult to maintain the thermal conductivity at 270 W / mK or more because the area where the heat is conducted in the thickness direction of the plate material is reduced, so that it is preferably 10 to 20%.

The thermal conductivity of the heat sink member in the thickness direction may be 270 W / mK or more, preferably 300 W / mK or more, and more preferably 310 W / mK or more.

The thermal expansion coefficient of the heat sink material in the major axis direction may be 8.0 to 9.0 x 10 < ^-6 > / K.

The heat dissipation plate material has a coefficient of thermal expansion in the major axis direction similar to a coefficient of thermal expansion of a material constituting the high output semiconductor, so that the high output semiconductor device can be mounted through two or more brazing processes.

[Example]

In the embodiment of the present invention, a heat sink material having the structure of FIG. 2 is manufactured through the following steps.

The heat sink material having the structure of FIG. 2 preferentially fabricates an intermediate layer composed of the Mo plate material and Cu in FIG. 3, and the manufacturing method thereof is to laminate the Mo plate material and the Cu plate material, A manufacturing process of cutting to a thickness of 40 to 70% of the total thickness of the product having a suitable thickness is carried out.

Thereafter, Cu and Mo, which are the first layer and the five layers, Cu-Mo alloy, which is the fourth layer and the fourth layer, and the third layer prepared through the cutting are arranged in order and then integrated through energization and pressure bonding.

First, the Cu plate material applied as the first layer and the fifth layer is prepared by cutting a plate having a thickness of about 200 mu m, a length of 100 mm, and a width of 100 mm, and a Cu-Mo plate material having a thickness of about 50 mu m applied as the second and fourth layers (Cu 60% by weight - Mo 40% by weight) was cut into sheets of 100 mm long and 100 mm wide and prepared.

Subsequently, the third layer was produced by repeatedly laminating a Cu plate material having a thickness of about 300 탆 and a Mo plate having a thickness of about 50 탆 so that the total thickness was not less than 50 mm and bonding them at a pressure of 40 MPa and a temperature of 950 캜 by electrification- Prepare. The bonded bulk material was cut in a direction perpendicular to the stacking direction of the material by applying a multi-wire saw to prepare a plate-shaped intermediate material having a thickness of about 700 μm.

Thereafter, the first layer, the second layer, the third layer, the fourth layer, and the fifth layer prepared in this order are laminated in this order, and the bonding is progressed through the energized pressure bonding method. In vacuum, the bonding temperature is 950 ° C, To produce a composite plate having the structure shown in Fig.

FIGS. 4 and 5 show microscope images of the front and side surfaces of the actually produced composite plate. It is confirmed that the Cu-Mo alloy layer and the Mo layer are formed in the Cu layer in the shape as shown in FIG.

As described above, in the embodiment of the present invention, the respective plates constituting the composite plate are stacked and then energized and pressed. However, the present invention is not limited to the method of stacking various types of plate materials such as a plate made of powder by sintering method or various deposition methods May be used.

Table 1 below shows thermal conductivity and thermal expansion coefficient of the heat sink member according to the embodiment of the present invention and Comparative Example 1 and Comparative Example 2 having the conventional laminate structure.

In the case of Comparative Example 1, the Cu / Cu-Mo alloy / Cu three-layered structure shown in Fig. 6 has a three-layer laminated structure, and the upper and lower Cu layers have a thickness of 20% The thickness is 80% of the total thickness.

In the case of Comparative Example 2, the five layers of the Cu / Mo / Cu / Mo / Cu laminated structure shown in FIG. 7 were formed, and the thickness of the upper and lower Cu layers was about 40% The thickness of the layer is about 45% of the total thickness, and the thickness of the Mo layer is about 15% of the total thickness.

Plane direction (long axis direction)
Coefficient of thermal expansion
(× 10 ^-6 / K) Thickness direction of plate material
Thermal conductivity
(W / mK) Comparative Example 1 8.0 220 Comparative Example 2 7.0 230 Example 8.2 316

As shown in Table 1, the coefficient of thermal expansion of the heat sink material according to the embodiment of the present invention is 8.2 × 10 ^-6 / K in the major axis direction, and is not different from the coefficient of thermal expansion of the ceramic material constituting the high- The problem of warping or peeling does not occur when two or more elements are mounted and the thermal conductivity in the thickness direction of the plate material is 316 W / mK, which is significantly improved as compared with Comparative Example 1 and Comparative Example 2, And the heat conductivity is such that it can be used for heat treatment.

In other words, the heat sink material according to the embodiment of the present invention improves the thermal conductivity in the thickness direction of the plate material, and at the same time, the coefficient of thermal expansion in the plane direction (the long axis direction) does not decrease to such a degree that the bonding property with the semiconductor device It was implemented.

Claims (11)

A heat sink material having a structure in which two or more materials are laminated,
The first layer, the second layer, the third layer, the fourth layer and the fifth layer are sequentially stacked in the thickness direction of the heat sink member,
Wherein the second layer and the fourth layer are made of a material having a smaller coefficient of thermal expansion than the first layer and the fifth layer,
Wherein the third layer comprises a first material layer and a second material layer,
The second material layer has a thermal expansion coefficient different from that of the first material layer and is formed to extend in contact with the second and fourth layers in the thickness direction with a predetermined thickness inside the first material layer, The first material layer and the second material layer are repeated in a plurality of alternating directions along any one of a direction in which the length direction of the heat dissipation plate material is short (short axis direction) and a long direction (long axis direction) A heat radiating plate having a partition wall structure. The method according to claim 1,
Wherein the first material layer and the second material layer form a barrier rib structure along the minor axis when viewed in cross section. The method according to claim 1,
Wherein the first layer and the fifth layer are made of a material containing Cu. The method according to claim 1,
Wherein the second layer and the fourth layer are made of an alloy including Cu and Mo. The method according to claim 1,
Wherein the first material layer is made of a material containing Cu and the second material layer is made of a material containing Mo. The method according to claim 1,
Wherein the thickness of the first layer and the fifth layer in the thickness direction of the heat sink member is 10 to 30% of the total thickness. The method according to claim 1,
Wherein the thickness of the second layer and the fourth layer in the thickness direction of the heat sink member is 5 to 20% of the total thickness. The method according to claim 1,
Wherein the volume of the second material layer comprises 10 to 20% of the total volume of the third layer. The method according to claim 1,
Wherein the heat conductivity in the thickness direction is 270 W / mK or more. The method according to claim 1,
And a coefficient of thermal expansion in a direction of a relatively long length in the plane direction of the heat sink material is 7.0 to 9.0 × 10 ^-6 / K. The method according to claim 1,
Wherein said element is packaged in parallel in two or more of high power semiconductor elements.

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