Diamond-based composite heat sink

Abstract

The utility model provides a diamond-based composite heat sink. The diamond-based composite heat sink comprises a diamond layer, a transition layer and a carbon material-metal composite layer which are sequentially stacked and connected together, the transition layer is chromium, tungsten, titanium or molybdenum; and the carbon material-metal composite layer is diamond copper, diamond silver or graphite aluminum. According to the utility model, the diamond and the carbon material-metal composite material are compounded together to form the composite heat sink, and when in use, the diamond is connected with the radiator through the carbon material-metal composite material, thereby solving the problem that the coefficient of thermal expansion of the diamond is not matched with that of thermal expansion of the radiator, optimizing the overall heat dissipation performance of the heat sink, simplifying the subsequent packaging process, and improving the production efficiency. And the product reliability is improved. In addition, the diamond is directly connected with the carbon material-metal composite material through the transition layer, the binding force between the diamond and the carbon material-metal composite material can be improved, and the stability of the structure is guaranteed.

Description

Technical Field

[0001] The utility model relates to a diamond / carbon material-metal composite heat sink, belonging to the technical field of electronic packaging. Background Art

[0002] The heat dissipation problem has become one of the biggest problems affecting the working efficiency, reliability and service life of semiconductor power devices such as power semiconductors, laser diodes, high-power LEDs, and supercomputer chips. Due to its excellent heat dissipation performance, diamond has received extensive attention as a new generation of high-performance heat dissipation material. However, there are still the following problems when diamond is directly used as a heat sink: First, there is a large mismatch between the thermal expansion coefficient of diamond and traditional heat sinks (aluminum, copper), and there is a large stress when directly welding with the heat sink, which has an adverse impact on the chip packaging and quality reliability; Second, the production cost of large-size diamond is relatively high, which restricts its application scenarios. Content of the Utility Model

[0003] The purpose of the utility model is to provide a diamond-based composite heat sink to solve the problems such as high production cost and mismatch of thermal expansion coefficient with the heat sink existing in the diamond-based heat sink.

[0004] The utility model is realized through the following technical solutions:

[0005] A diamond-based composite heat sink includes a diamond layer, a transition layer and a carbon material-metal composite layer which are stacked and connected together in sequence; the transition layer is chromium, tungsten, titanium or molybdenum; the carbon material-metal composite layer is diamond copper, diamond silver or graphite aluminum.

[0006] Preferably, the diamond layer is single-crystal diamond or polycrystalline diamond.

[0007] Preferably, the thickness of the diamond layer is 0.1 - 3 mm.

[0008] Preferably, the thickness of the transition layer is 0.1 - 5 microns.

[0009] Preferably, the total thickness of the composite heat sink is 0.3 - 5 mm.

[0010] Preferably, a groove is formed on one surface of the carbon material-metal composite layer, and the transition layer and the diamond layer are sequentially arranged on the bottom surface of the groove.

[0011] Preferably, one surface of the carbon material-metal composite layer is a plane, and the transition layer and the diamond layer are sequentially arranged on the plane.

[0012] Preferably, the diamond layer, the transition layer and the carbon material-metal composite layer are connected together by a hot pressing connection method.

[0013] Compared with the prior art, the utility model has the following beneficial effects:

[0014] In the utility model, diamond is combined with a carbon material-metal composite material to form a composite heat sink. During use, the diamond is connected to the radiator through the carbon material-metal composite material, thereby solving the problem of mismatched thermal expansion coefficients with the radiator, optimizing the overall heat dissipation performance of the heat sink, simplifying the subsequent packaging process, and thus improving the product reliability. And after being combined with the carbon material-metal composite material, the size of the diamond can be greatly reduced, thereby solving the problem of high production cost existing in the diamond-based heat sink. Compared with the heat sink formed by the carbon material-metal composite material itself, the diamond sheet directly connected to the chip has higher heat dissipation performance and more matched thermal expansion coefficient, and is more suitable for high-power heating scenarios. In addition, the diamond and the carbon material-metal composite material are directly connected through a transition layer, which can improve the bonding force between the diamond and the carbon material-metal composite material and ensure the structural stability. The utility model provides a new technical solution for further simplifying the packaging structure and process, improving the heat dissipation capacity of semiconductor devices, and thus enhancing the reliability and quality stability.

[0015] Further, the thickness of the transition layer is only 0.1 to 5 microns, which can ensure the structural stability without affecting the heat dissipation effect.

[0016] Further, a groove is formed on one surface of the carbon material-metal composite layer, and the transition layer and the diamond layer are sequentially arranged on the bottom surface of the groove, thereby forming an embedded structure. Compared with the non-embedded structure, the embedded structure improves the long-term use stability of the product by laterally wrapping the diamond.

[0017] Further, the diamond layer and the carbon material-metal composite layer are connected together in a non-welding manner, which can overcome the problems of extended heat dissipation path, complex packaging structure and process, low yield, and high packaging cost caused by using solder as the connection layer. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 Schematic diagram of non-embedded connection between the carbon material-metal composite layer and the diamond layer.

[0020] Figure 2 Schematic diagram of embedded connection between the carbon material-metal composite layer and the diamond layer. Detailed implementation manners

[0021] The following describes the implementation manners of the present utility model through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present utility model from the content disclosed in this specification. The present utility model can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present utility model.

[0022] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0023] The technical solution adopted by the present utility model is to compound diamond and carbon material-metal into a whole as a packaging heat sink.

[0024] The composite heat sink described in the present utility model includes a diamond layer 1, a transition layer 2, and a carbon material-metal composite layer 3 that are sequentially laminated and connected together; the transition layer 2 is one of chromium, tungsten, titanium, and molybdenum. The carbon material-metal composite layer 3 is a composite layer of a high thermal conductivity carbon material and a metal. The high thermal conductivity carbon material is diamond, graphite, or carbon fiber, and the metal is copper, silver, or aluminum. The carbon material-metal composite layer 3 is specifically diamond copper, diamond silver, or graphite aluminum.

[0025] The diamond copper, diamond silver, or graphite aluminum adopted in the present utility model are all obtained according to the existing technology.

[0026] The diamond layer 1 is single-crystal diamond or polycrystalline diamond, with a thickness of 0.1 to 3 mm and a thermal conductivity of 1000 to 2500 W / mK. The thickness of the transition layer 2 is 0.1 to 5 microns. The single-crystal diamond or polycrystalline diamond are all obtained according to the existing technology.

[0027] The total thickness of the composite heat sink described in the present utility model is 0.3 to 5 mm, and the thermal conductivity is 300 to 1000 W / mK.

[0028] A groove is formed on one surface of the carbon material-metal composite layer 3, and the transition layer 2 and the diamond layer 1 are sequentially arranged on the bottom surface of the groove, thereby forming an embedded structure.

[0029] Of course, it can also be a non-embedded structure, that is, one surface of the carbon material-metal composite layer 3 is a plane, and the transition layer 2 and the diamond layer 1 are sequentially arranged on the plane.

[0030] Example 1

[0031] The composite heat sink described in this embodiment includes a diamond layer 1, a transition layer 2, and a carbon material-metal composite layer 3 that are sequentially laminated and connected together; the transition layer 2 is a chromium layer with a thickness of 1 micron; the carbon material-metal composite layer 3 is diamond copper with a thickness of 500 microns; the diamond layer 1 is single-crystal diamond with a thickness of 200 microns. The surface of the carbon material-metal composite layer 3 is flat, and the transition layer 2 and the diamond layer 1 are sequentially arranged on the flat surface to form a non-embedded structure, as Figure 1 shown.

[0032] The preparation method of the composite heat sink described in this embodiment is as follows: A 1-micron-thick chromium layer is sputtered on the surface of a 200-micron-thick single-crystal diamond wafer with a thermal conductivity of 2000 W / mK by PVD. The single-crystal diamond wafer and diamond copper are pressed together by hot pressing (the side of the single-crystal diamond wafer with the chromium layer contacts the diamond copper). Among them, the thickness of the diamond copper is 500 microns and the thermal conductivity is 600 W / mK. The pressed sample is ground and polished to obtain a heat sink with a thickness of 690 microns. After testing, the equivalent thermal conductivity of this diamond / diamond copper composite heat sink is 950 W / mK.

[0033] Example 2

[0034] Different from Example 1, the connection method between the carbon material-metal composite layer 3 and the diamond layer 1 is embedded. The surface of the carbon material-metal composite layer 3 has a groove, and the transition layer 2 and the diamond layer 1 are sequentially arranged on the bottom surface of the groove to form an embedded structure, as Figure 2 shown.

[0035] The preparation method of the composite heat sink described in this embodiment is as follows: A 200-micron-deep groove is formed on the top of the diamond copper by laser processing, and the single-crystal diamond wafer is embedded in the groove (the side of the single-crystal diamond wafer with the chromium layer contacts the bottom surface of the groove), and then hot pressing is performed to form the target part. After testing, the equivalent thermal conductivity of this diamond / diamond copper composite heat sink is 900 W / mK.

[0036] Example 3

[0037] The composite heat sink described in this embodiment includes a diamond layer 1, a transition layer 2, and a carbon material-metal composite layer 3 that are sequentially laminated and connected together; the transition layer 2 is a titanium layer with a thickness of 1 micron; the carbon material-metal composite layer 3 is diamond silver with a thickness of 500 microns; the diamond layer 1 is single-crystal diamond with a thickness of 300 microns. The surface of the carbon material-metal composite layer 3 is flat, and the transition layer 2 and the diamond layer 1 are sequentially arranged on the flat surface to form a non-embedded structure, as Figure 1 shown.

[0038] The preparation method of the composite heat sink in this embodiment is as follows: A 1-μm-thick titanium layer is sputtered on the surface of a single-crystal diamond sheet with a thickness of 300 μm and a thermal conductivity of 2000 W / mK by PVD. The single-crystal diamond sheet and diamond silver are pressed together by hot pressing (the side of the single-crystal diamond sheet with the titanium layer contacts the diamond silver). Among them, the thickness of the diamond silver is 500 μm and the thermal conductivity is 700 W / mK. The pressed sample is ground and polished to obtain a heat sink with a thickness of 690 μm. After testing, the equivalent thermal conductivity of the diamond / diamond silver composite heat sink is 1050 W / mK.

[0039] Example 4

[0040] The composite heat sink described in this embodiment includes a diamond layer 1, a transition layer 2, and a carbon material-metal composite layer 3 that are sequentially stacked and connected together; the transition layer 2 is a titanium layer with a thickness of 1 μm; the carbon material-metal composite layer 3 is graphite aluminum with a thickness of 2 mm; the diamond layer 1 is polycrystalline diamond with a thickness of 300 μm. The surface of the carbon material-metal composite layer 3 is flat, and the transition layer 2 and the diamond layer 1 are sequentially arranged on the plane to form a non-embedded structure, as Figure 1 shown.

[0041] A 1-μm-thick titanium layer is sputtered on the surface of a polycrystalline diamond sheet with a thickness of 300 μm and a thermal conductivity of 1400 W / mK by PVD. The polycrystalline diamond sheet and graphite aluminum are pressed together by hot pressing (the side of the single-crystal diamond sheet with the titanium layer contacts the graphite aluminum). Among them, the thickness of the graphite aluminum is 2 mm and the thermal conductivity is 500 W / mK. The pressed sample is ground and polished to obtain a heat sink with a thickness of 2.2 mm. After testing, the equivalent thermal conductivity of the diamond / graphite aluminum composite heat sink is 550 W / mK.

[0042] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A diamond-based composite heat sink, characterized in that: The invention comprises a diamond layer (1), a transition layer (2) and a carbon material-metal composite layer (3) which are sequentially stacked and connected together; the transition layer (2) is chromium, tungsten, titanium or molybdenum; and the carbon material-metal composite layer (3) is diamond copper, diamond silver or graphite aluminum.

2. The diamond-based composite heat sink according to claim 1, characterized in that: The diamond layer (1) is single crystal diamond or polycrystalline diamond.

3. The diamond-based composite heat sink according to claim 1, characterized in that: The thickness of the diamond layer (1) is 0.1-3 mm.

4. The diamond-based composite heat sink according to claim 1, characterized in that: The thickness of the transition layer (2) is 0.1 to 5 micrometers.

5. The diamond-based composite heat sink according to claim 1, characterized in that: The total thickness of the composite heat sink is 0.3-5 mm.

6. The diamond-based composite heat sink according to claim 1, characterized in that: A groove is provided on one surface of the carbon material-metal composite layer (3), and the transition layer (2) and the diamond layer (1) are arranged in sequence on the bottom surface of the groove.

7. The diamond-based composite heat sink according to claim 1, characterized in that: One surface of the carbon material-metal composite layer (3) is a plane, and the transition layer (2) and the diamond layer (1) are sequentially arranged on the plane.

8. The diamond-based composite heat sink according to claim 1, characterized in that: The diamond layer (1), the transition layer (2) and the carbon material-metal composite layer (3) are connected together by means of thermal compression bonding.

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