Diamond copper bar heat sink sheet with multilayer structure

Abstract

The utility model discloses a diamond copper bar heat sink sheet with a multilayer structure. The diamond copper bar heat sink sheet comprises a diamond copper core material and a metal coating layer, the bar heat sink sheet is characterized in that the upper and lower surfaces of the bar heat sink sheet in the thickness direction are single-layer metal coating layers prepared from molybdenum alloy or tungsten alloy; the other four side surfaces are multi-layer structure metal coating layers prepared by alternately arranging any one of molybdenum alloy and tungsten alloy and copper; the arrangement direction of each metal layer in the multi-layer structure metal coating layer is the thickness direction of the bar heat sink sheet; the utility model provides a diamond copper bar heat sink sheet with a multilayer structure, which can realize all-metal coating of a diamond copper core material so as to meet the high-precision processing requirement, meanwhile, the heat dissipation effect is better through the structural design of a heat dissipation surface, the thermal expansion coefficient of the obtained heat sink sheet is better matched with that of a laser chip, and the heat sink sheet has good heat dissipation performance. And the application range of the copper-diamond composite material is expanded.

Description

Technical Field

[0001] The utility model belongs to the technical field of heat sink materials, and in particular relates to a diamond copper bar heat sink sheet. Background Art

[0002] At present, the development trend of high-power semiconductor lasers is higher brightness, higher power, and higher reliability laser output. In order to achieve higher power output, the packaging form of semiconductor lasers is a high-density stacked structure, that is, a number of narrow laser bar units are stacked together, and each laser bar unit consists of a bar and tungsten copper sheets on both sides. Studies have shown that as the output power increases, the electro-optical conversion efficiency tends to decrease. This is because when the power output is high, the semiconductor laser will generate a lot of heat. This excess heat cannot be dissipated in time, which will cause the laser performance to decline and the electro-optical conversion efficiency to decrease. With the continuous improvement of the power density of domestic laser pump sources, the stable operation of high-power and high-heat flux devices in the military and civilian fields faces the problem of insufficient heat dissipation capacity. At present, the bar heat sink material on the market is mainly Cu / W material (thermal conductivity <220W / mK), and it is urgent to improve the thermal conductivity of the bar heat sink to enhance heat dissipation. At the same time, for the bar unit, the heat sink needs to have a thermal expansion coefficient close to that of the chip. When the thermal expansion coefficients of the two are very different, the chip will bend slightly, which will directly cause the laser emitted by the chip to be misaligned and the overall light emission of the semiconductor laser array to bend.

[0003] Although the thermal conductivity of diamond / copper composite materials is very high (thermal conductivity>600W / mK) and the thermal expansion coefficient is close to that of bar bars, diamond is the hardest of all materials and difficult to process. The surface roughness after processing is very large and the processing accuracy is low. The gold plating and welding in the subsequent processes cannot meet the use conditions of bar bar heat sinks. Simply coating the diamond copper with a metal layer on the top and bottom, the final processing accuracy still cannot meet the use requirements. Therefore, the diamond copper composite material suitable for bar bar heat sinks must be fully metal-coated and use metal processing technology to achieve high processing accuracy requirements.

[0004] At the same time, the heat dissipation method of the bar heat sink is considered, that is, it relies on longitudinal (thickness direction) conduction heat to remove the heat from the chip. The chip conducts the heat to the diamond copper composite material encapsulated in the inner layer, and then conducts the heat horizontally, and finally dissipates the heat outward through the metal shell layer on the four sides. However, since the metal shell layer is a low thermal conductivity layer compared to the diamond copper composite material, its lateral conduction heat dissipation effect is not ideal, and the heat cannot be quickly removed, thus limiting the use of diamond copper composite materials in high-power density chip heat sinks. Utility Model Content

[0005] In view of the problem that the processing of diamond-copper composite materials is difficult to meet the processing accuracy requirements of bar heat sinks, and the problem that the heat dissipation effect of the metal shell is not good enough, the utility model provides a diamond-copper bar heat sink with a multi-layer structure, which can achieve full metal cladding of the diamond copper core material to meet the high-precision processing requirements. At the same time, the heat dissipation effect is better achieved through the structural design of the heat dissipation surface. The thermal expansion coefficient of the obtained heat sink is more matched with the laser chip, thereby expanding the application range of the copper-diamond composite material.

[0006] In order to achieve the above purpose, the technical solutions adopted are as follows:

[0007] A multi-layer diamond copper bar heat sink, comprising a diamond copper core material and a metal cladding layer;

[0008] The upper and lower surfaces of the bar heat sink in the thickness direction are single-layer metal coating layers made of molybdenum alloy or tungsten alloy;

[0009] The other four sides are multi-layered metal cladding layers made of any one of molybdenum alloy and tungsten alloy and copper arranged alternately;

[0010] The arrangement direction of each metal layer in the multi-layer metal cladding layer is the thickness direction of the bar heat sink.

[0011] According to the above solution, the thickness of the bar heat sink is 0.3-6 mm, the thickness of the diamond copper core material is 0.1-5 mm, and the thickness of the metal cladding layer is 0.05-0.2 mm.

[0012] According to the above scheme, the number of layers of the multi-layer metal coating layer is 2-15; the thickness of a single layer is 0.05-0.3 mm.

[0013] According to the above scheme, the diamond copper core material is a diamond copper composite material, wherein diamond particles are dispersed phase, copper is continuous phase, and the volume fraction of diamond particles is 40-70%.

[0014] According to the above scheme, a coating is prepared on the surface of the diamond particles, the particle size of the diamond particles is 40-800 μm, and the thickness of the coating is 0.01-0.8 μm.

[0015] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0016] The alloy coating layer on the upper and lower sides of the diamond copper core material is the surface in direct contact with the chip and is the surface with the highest processing precision requirements. The use of a whole metal layer is conducive to achieving a smooth surface, facilitating close fitting with the chip and stable heat dissipation. The metal coating layer on the contact surface with the chip is made of tungsten copper or molybdenum copper, which is a metal layer with uniform composition, and the thermal expansion coefficient matches the chip, which is conducive to stable operation of the chip and improves structural stability.

[0017] The metal coating on the four sides of the diamond copper core is a multilayer structure of tungsten alloy or molybdenum alloy and copper. The thermal conductivity of tungsten alloy and molybdenum alloy is less than 220W / mK, while the thermal conductivity of copper is 397W / mK. The advantages of tungsten alloy and molybdenum alloy are low thermal expansion coefficient: (5-7)×10 -6 / oC, close to the chip, and consistent with the thermal expansion coefficient of the diamond copper core material. In practical applications, the four long sides of the bar are required to be right angles and have high dimensional accuracy. Only by converting the processing of the diamond copper composite material into the processing of metal can the product requirements be met, so the side must be covered with a metal layer. In the selection of the side metal layer, although copper has a high thermal conductivity, if the side is made of pure copper, the thermal expansion coefficient is too large (17.2×10 -6 / oC), it will cause chip failure. If other metals are used for the side metal layer, the thermal conductivity is low, the heat dissipation efficiency is low, and the chip failure will also be caused. The utility model uses a multi-layer metal structure as the side metal coating layer. The chip conducts the heat to the diamond copper composite material encapsulated in the inner layer, and the heat is finally dissipated outward through the metal coating layers on the four sides (the multi-layer structure of copper and tungsten alloy or the multi-layer structure of copper and molybdenum alloy). The copper in the multi-layer structure on the side quickly dissipates the heat, with high heat dissipation efficiency, thereby improving chip stability.

[0018] According to the design of the diamond volume fraction, as well as the composition and thickness of the metal shell, the thermal conductivity and thermal expansion coefficient of the obtained bar heat sink can be quantitatively designed and adjusted within a certain range. The thermal conductivity of the heat sink obtained by this novel method is 400-800W / mK, and the average linear expansion coefficient in the range of 25℃-100℃ is (5-9)×10 -6 / ℃. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 : Schematic diagram of the structure of multi-layer diamond copper bar heat sink.

[0020] Among them, 1-single-layer metal cladding; 2-multi-layer structure metal cladding; 3-diamond copper core material. DETAILED DESCRIPTION

[0021] The following examples further illustrate the technical solution of the present invention, but are not intended to limit the protection scope of the present invention.

[0022] The specific implementation method provides a multi-layer structure diamond copper bar heat sink, referring to the attached Figure 1As shown; it includes a diamond copper core material 1 and a metal cladding layer (1, 2); the upper and lower surfaces in the thickness direction of the bar heat sink are single-layer metal cladding layers 1 made of molybdenum alloy or tungsten alloy; the other four sides are multi-layer structure metal cladding layers 2 made of any one of molybdenum alloy, tungsten alloy and copper arranged alternately; the arrangement direction of each metal layer in the multi-layer structure metal cladding layer 2 is the thickness direction of the bar heat sink.

[0023] Specifically, the molybdenum content in the molybdenum alloy is 50-90%, and the tungsten content in the tungsten alloy is 50-90%. The thermal conductivity of tungsten alloy and molybdenum alloy is less than 220W / mK, while the thermal conductivity of copper is 397W / mK. The advantages of tungsten alloy and molybdenum alloy are low thermal expansion coefficient: (5-7)×10 -6 / oC, which is close to the chip and consistent with the thermal expansion coefficient of the diamond copper core material.

[0024] The diamond copper core is wrapped in a metal cladding layer. The multi-layer metal cladding layer around it is a molybdenum alloy or tungsten alloy and copper alternately distributed, that is, a layer of alloy and a layer of copper are staggered. The single-layer metal cladding layer on the top and bottom is a whole piece of tungsten alloy or molybdenum alloy. The metal cladding layers on the top and bottom are used to protect the diamond copper core material inside and prevent the diamond particles from being exposed. The multi-layer metal cladding design around it can achieve rapid heat dissipation and improve chip stability. The whole alloy design on the top and bottom can meet high-precision processing requirements and directly fit the chip. If all the sides are made of pure copper, the thermal expansion coefficient will be too large (17.2×10 -6 / oC), will cause chip failure. If other metals are used on all sides, the thermal conductivity is low, which will also cause chip failure. The new type uses a multi-layer metal coating layer on the heat dissipation surface to overcome the above problems.

[0025] Specifically, the diamond copper core material is a diamond copper composite material, wherein diamond particles are dispersed phase, copper is continuous phase, and the volume fraction of diamond is 40-70%. A coating is prepared on the surface of the diamond particles, the original particle size of the diamond particles is 40-800 μm, and the coating thickness is 0.01-0.8 μm. The presence of the diamond particle coating helps to improve the wettability of the metal phase and the diamond particles and increase the bonding strength.

[0026] Specifically, the thickness of the bar heat sink is 0.3-6 mm, the thickness of the diamond copper core material is 0.1-5 mm, the thickness of the metal cladding layer is 0.05-0.2 mm, the number of layers of the multi-layer structure metal cladding layer is 2-15 layers, and the thickness of a single layer is 0.05-0.3 mm.

[0027] By designing the diamond volume fraction, alloy composition and thickness, the heat sink obtained can replace the use of tungsten copper in the bar heat sink, with low density, which is conducive to weight reduction. At the same time, the thermal conductivity is 400-800W / mK, and the average linear expansion coefficient in the range of 25℃-100℃ is (5-9)×10 -6 / ℃. It expands the application scope of copper diamond composite materials.

Claims

1. A multi-layer diamond copper bar heat sink, comprising a diamond copper core material and a metal cladding layer; characterized in that The upper and lower surfaces in the thickness direction of the bar heat sink are single-layer metal coatings made of molybdenum alloy or tungsten alloy; the other four sides are multi-layer metal coatings made of any one of molybdenum alloy, tungsten alloy and copper arranged alternately; the arrangement direction of each metal layer in the multi-layer metal coating is the thickness direction of the bar heat sink.

2. The multi-layer diamond copper bar heat sink as claimed in claim 1, characterized in that The thickness of the bar heat sink is 0.3-6 mm, the thickness of the diamond copper core material is 0.1-5 mm, and the thickness of the metal cladding layer is 0.05-0.2 mm.

3. The multi-layer diamond copper bar heat sink as claimed in claim 1, characterized in that The number of layers of the multi-layer metal cladding layer is 2-15; the thickness of a single layer is 0.05-0.3 mm.

4. The multi-layer diamond copper bar heat sink as claimed in claim 1, characterized in that The diamond copper core material is a diamond copper composite material, wherein diamond particles are dispersed phase, copper is continuous phase, and the volume fraction of diamond particles is 40-70%.

5. The multi-layer diamond copper bar heat sink as claimed in claim 4, characterized in that The surface of the diamond particles is prepared with a coating, the particle size of the diamond particles is 40-800 μm, and the thickness of the coating is 0.01-0.8 μm.

Images