Preparation method of metal heat-conducting gasket and metal heat-conducting gasket

Abstract

The invention provides a preparation method of a metal heat-conducting gasket and the metal heat-conducting gasket, and the preparation method of the metal heat-conducting gasket comprises the following steps: step 1, alloy preparation: filling 40-70% of indium and 30-60% of tin into a vacuum melting furnace, and preparing an indium-tin alloy; 2, cold rolling, wherein the obtained indium-tin alloy raw material is subjected to acid pickling, rolling, degreasing and annealing treatment, so that the material is formed; step 3, surface treatment: feeding the cold-rolled product into a mold with lines for surface embossing treatment, so that the compressibility of the heat-conducting gasket is improved, and the contact thermal resistance is reduced; and fourthly, die cutting is conducted, specifically, the product subjected to surface treatment is fed into a die cutting machine and cut according to the set size and shape, and the metal heat-conducting gasket is obtained. According to the technical scheme, the technical problems that in the prior art, an indium-based metal heat conduction material is large in contact thermal resistance, low in heat conductivity, complex in preparation process and high in cost are solved.

Description

Technical Field

[0001] This invention relates to the field of thermal interface materials technology, and in particular to a method for preparing a metal thermally conductive pad and the metal thermally conductive pad itself. Background Technology

[0002] With the continuous development of high-performance computing such as AI and big data, the requirements for chip computing power are constantly increasing. In 2022, the power consumption of a single CPU in Intel's fourth-generation server processor exceeded 350W; the power consumption of a single GPU in NVIDIA exceeded 700W. The heat flux density is constantly rising, and the resulting heat dissipation problem has become one of the major challenges hindering the improvement of computing performance.

[0003] Interfacial thermal conduction is a crucial aspect of chip heat dissipation, and the contact thermal resistance it generates can account for more than 50% of the total system thermal resistance. This situation has led to an urgent need for high-performance thermal interface materials. Currently, mainstream thermal interface materials are based on organosilicon compounds, which inherently have low thermal conductivity, generally below 10 W / (m·K). Furthermore, another major problem facing traditional silicon-based thermal interface materials is the volatilization of organic matter after prolonged use, resulting in performance degradation and a short lifespan. These two key issues make interfacial thermal transfer a thorny bottleneck problem, significantly hindering further improvements in the performance of high-performance chips and power devices. However, the intrinsically high thermal conductivity and good stability of metal-based thermal conductive materials can effectively solve these problems.

[0004] In the prior art, patent document CN101022712A proposes a low-melting-point indium-based metal thermal conductive material with high thermal conductivity, but its low melting point poses a risk of leakage and electrical conductivity. Patent document CN109957695A further improves the melting point of indium-based metal thermal conductive materials, but its process is complex and its interface properties are poor. Patent document CN115847947A proposes a multilayer composite indium-based thermal interface material with extremely high thermal conductivity, but its preparation process is cumbersome and the material cost is high, resulting in limited applicability.

[0005] As can be seen from the above, research on indium-based metal thermal pads mainly focuses on improving thermal conductivity and melting point. However, in actual heat conduction paths, the thickness of the metal interface material itself is extremely small, and the reduction in conductive thermal resistance resulting from improved thermal conductivity has little impact on heat dissipation performance. Furthermore, the contact thermal resistance between the two ends of the thermal interface material and the heat source and radiator accounts for a large proportion of the total thermal resistance, and the quality of the contact characteristics significantly affects the performance of the heat dissipation system. Patent document CN114874758A utilizes liquid metal to improve the surface properties of indium-based metals, which can significantly reduce interfacial contact thermal resistance; however, it carries a certain risk of leakage, and metals such as gallium can corrode commonly used aluminum radiators. This solution also has high material costs and complex manufacturing processes.

[0006] As the performance of high-performance chips and power devices continues to improve, the industry's demand for high-performance indium-based thermal interface materials is becoming increasingly urgent. However, as an expensive metal, indium is far more expensive than existing silicon-based thermal interface materials, which limits its widespread application. Summary of the Invention

[0007] This invention provides a method for preparing a metal thermally conductive pad and the metal thermally conductive pad itself, which can solve the technical problems of high contact thermal resistance, low thermal conductivity, complex preparation process, and high cost of indium-based metal thermally conductive materials in the prior art.

[0008] According to one aspect of the present invention, a method for preparing a metal thermally conductive pad is provided, the method comprising: Step 1, alloy preparation: filling a vacuum melting furnace with 40-70% indium and 30-60% tin to prepare an indium-tin alloy; Step 2, cold rolling: subjecting the obtained indium-tin alloy raw material to pickling, rolling, degreasing and annealing to form the material; Step 3, surface treatment: feeding the cold-rolled product into a textured mold for surface embossing to improve the compressibility of the thermally conductive pad and reduce contact thermal resistance; Step 4, die cutting: feeding the surface-treated product into a die-cutting machine to cut according to a set size and shape to obtain a metal thermally conductive pad.

[0009] Furthermore, in step one, indium and tin are loaded in sequence according to their melting points, from low to high.

[0010] Furthermore, in step one, the metal melting temperature is greater than or equal to 300°C, the melting time is greater than or equal to 10 minutes, and the vacuum degree is less than or equal to 10 Pa.

[0011] Furthermore, the thickness of the metal thermal pad after step two is 0.05mm to 1mm.

[0012] Furthermore, the thickness of the metal thermal pad after step three is 0.1mm to 1.5mm.

[0013] Furthermore, in step one, the purity of indium is greater than or equal to 99.99%, and the purity of tin is greater than or equal to 99.99%.

[0014] According to another aspect of the invention, a metal thermal pad is provided, which is made of an indium-tin binary alloy.

[0015] Furthermore, the indium-tin alloy comprises 40-70% indium and 30-60% tin by mass.

[0016] Furthermore, the thermal pad has a melting point greater than 100°C and undergoes no phase change during use.

[0017] Furthermore, the metal thermal pad is prepared using the metal thermal pad preparation method described above.

[0018] The present invention provides a method for preparing a metal thermal pad, which aims to solve the "thermal barrier" problem faced by high heat flux density chips. This method belongs to the field of thermal interface materials. The novel metal thermal pad is made of an indium-tin binary alloy, comprising 40-70% indium and 30-60% tin by mass. The metal thermal pad is prepared by melting the alloy, cold rolling, surface treatment, and die-cutting. The novel metal thermal pad provided by this invention features high performance, low cost, low contact thermal resistance, and excellent stability, meeting the requirements of high-performance chips and power devices. Attached Figure Description

[0019] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0020] Figure 1 This is a typical application scenario of the metal thermally conductive material in the embodiments of the present invention;

[0021] Figure 2 It is the metal thermally conductive pad in Embodiment 1 of the present invention;

[0022] Figure 3 This is the curve showing the relationship between the contact thermal resistance and pressure of the metal thermally conductive pad in Embodiment 1 of the present invention;

[0023] Figure 4 This refers to the melting point test results of the metal thermal pad in Embodiment 1 of the present invention;

[0024] Figure 5 These are the performance stability test results of the metal thermal pad in Embodiment 1 of the present invention at 250°C for 100 hours;

[0025] Figure 6 The results are the performance stability test results of the metal thermal pad in Embodiment 1 of the present invention under 100 thermal shock cycles of 20°C to 150°C.

[0026] The above figures include the following reference numerals:

[0027] 1: Chip heat source; 2: Metal thermal pad; 3: Heat sink. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0031] like Figures 1 to 6 As shown, a specific embodiment of the present invention provides a method for preparing a metal thermally conductive pad, the method comprising: Step 1, alloy preparation: filling a vacuum melting furnace with 40-70% indium and 30-60% tin to prepare an indium-tin alloy; Step 2, cold rolling: subjecting the obtained indium-tin alloy raw material to pickling, rolling, degreasing and annealing to form the material; Step 3, surface treatment: sending the cold-rolled product into a textured mold for surface embossing to improve the compressibility of the thermally conductive pad and reduce contact thermal resistance; Step 4, die cutting: sending the surface-treated product into a die-cutting machine to cut according to the set size and shape to obtain the metal thermally conductive pad.

[0032] This method provides a way to prepare a metal thermal pad, aiming to solve the "thermal barrier" problem faced by high heat flux density chips. Belonging to the field of thermal interface materials, the novel metal thermal pad is made of an indium-tin binary alloy, comprising 40-70% indium and 30-60% tin by mass. The metal thermal pad is prepared through alloy melting, cold rolling, surface treatment, and die cutting. The novel metal thermal pad provided by this invention features high performance, low cost, low contact thermal resistance, and excellent stability, meeting the requirements of high-performance chips and power devices. Therefore, compared with existing technologies, the method for preparing the metal thermal pad provided by this invention uses binary alloy technology to efficiently adjust and optimize the thermal properties of the thermal pad, and further prepares a uniform pattern on the surface of the metal pad through mold lamination. This significantly reduces the contact thermal resistance and usage cost of the metal pad. Specifically:

[0033] (1) The metal thermally conductive pad provided by this invention has excellent contact characteristics, with an interfacial contact thermal resistance of less than 0.2 cm under typical clamping force (40 psi). 2 (2) The thermal conductivity of the metal thermal pad provided by the present invention is greater than 50 W / (m·K), which is significantly improved compared with pure indium thermal pads; (3) The metal thermal pad provided by the present invention is made of indium-tin binary alloy, and the cost of tin is only one-tenth of that of indium, which can greatly reduce the material cost; (4) The metal thermal pad provided by the present invention has stable performance, no performance degradation during use, and no corrosion to common metals; (5) The metal thermal pad provided by the present invention has a melting point of not less than 100℃ and no phase change during use.

[0034] Furthermore, in step one, indium and tin are loaded in sequence according to their melting points, from low to high.

[0035] To ensure the quality of the metal gasket, in step one, the metal melting temperature is greater than or equal to 300°C, the melting time is greater than or equal to 10 minutes, and the vacuum degree is less than or equal to 10 Pa. The purity of indium is greater than or equal to 99.99%, and the purity of tin is greater than or equal to 99.99%.

[0036] Furthermore, the thickness of the metal thermal pad after step two is 0.05mm to 1mm. The thickness of the metal thermal pad after step three is 0.1mm to 1.5mm.

[0037] According to another aspect of the invention, a metal thermal pad is provided, which is made of an indium-tin binary alloy.

[0038] This configuration provides a novel metal thermal pad. The metal thermal pad provided by this invention features high performance, low cost, low contact thermal resistance, and excellent stability, meeting the requirements of high-performance chips and power devices.

[0039] Furthermore, the indium-tin alloy comprises 40–70% indium and 30–60% tin by mass. With this configuration, the cost of metallic tin is only one-tenth that of indium, significantly reducing material costs.

[0040] In this invention, the thermal pad has a melting point greater than 100°C and undergoes no phase change during use.

[0041] Furthermore, in this invention, the metal thermal pad is prepared using the metal thermal pad preparation method described above.

[0042] To gain a further understanding of the present invention, the following description is provided. Figures 1 to 6 The preparation method of the metal thermally conductive pad and the metal thermally conductive pad provided by the present invention will be described in detail.

[0043] like Figures 1 to 6 As shown, the present invention provides an indium-tin alloy thermally conductive interface material to solve the problems of high contact thermal resistance, low thermal conductivity, complex preparation process, and high cost of existing indium-based metal thermally conductive materials.

[0044] Metal thermal pads are made of indium-tin binary alloy. The cost of tin is only one-tenth that of indium, which can greatly reduce material costs.

[0045] Indium-tin alloys consist of 40-70% indium and 30-60% tin by mass.

[0046] The thermal pad has a melting point greater than 100℃, and there is no risk of phase change leakage during use.

[0047] The method for preparing the metal thermally conductive pad provided by the present invention includes the following steps: (1) Alloy preparation: Indium-tin alloy is prepared by filling a vacuum melting furnace with a certain mass fraction; (2) Cold rolling: The obtained indium-tin alloy raw material is subjected to pickling, rolling, degreasing, annealing and other treatments to form the material; (3) Surface treatment: The above-mentioned cold-rolled product is sent to a mold with texture for surface embossing treatment to improve the compressibility of the thermally conductive pad and reduce the contact thermal resistance; (4) Die cutting: The above-mentioned surface-treated product is sent to a die cutting machine and cut according to a suitable size and shape to obtain the metal thermally conductive pad.

[0048] The purity of indium and tin in step (1) should be no less than 99.99%.

[0049] In step (1), indium and tin should be filled in order of increasing melting point according to the metal.

[0050] In step (1), the metal melting temperature is not lower than 300℃, the melting time is not less than 10 minutes, and the vacuum degree is not greater than 10Pa.

[0051] The thickness of the metal thermal pad after step (2) is 0.05mm to 1mm.

[0052] The thickness of the metal thermal pad after step (3) is 0.1mm to 1.5mm.

[0053] Example 1

[0054] This embodiment relates to a metal thermally conductive pad and its preparation method. In this embodiment, the indium-tin alloy has a mass percentage content of 51% indium and 49% tin. The preparation process includes: loading the indium and tin metals in the above proportions into a vacuum melting furnace, setting the melting temperature to 350℃ and the melting time to be no less than 10 minutes, and removing the metals after they have completely melted into a sealed container for cooling; first, the obtained indium-tin alloy raw material is pickled with 10% dilute hydrochloric acid to ensure the surface cleanliness of the cold-rolled product; then, the indium-tin alloy is rolled, with a compression rate of no more than 50% for each roll, until the target thickness is reached; then, the metal surface is degreased with aviation kerosene to remove the lubricating grease adhering to the rolled material during rolling, so as to avoid contaminating the material surface during annealing; annealing is performed at 90℃ for 3 minutes to eliminate the work hardening generated during cold deformation, so as to restore the plasticity of the material and reduce the deformation resistance of the metal; the above-mentioned cold-rolled metal thermal conductive pads are fed into a steel mesh mold with a hole diameter of 200 micrometers and a hole spacing of 1mm for surface embossing treatment; after die cutting, the metal thermal conductive pads are obtained.

[0055] In this embodiment, the indium metal has a purity of 99.995%, and the tin metal has a purity of 99.99%. The thickness of the metal thermal pad after rolling is 0.1 mm, and the thickness of the metal thermal pad after surface treatment is 0.2 mm.

[0056] Tests showed that the metal thermal pad in this embodiment had a contact thermal resistance of only 0.16 cm²·K / W at 40 psi, a thermal conductivity of 53.5 W / (m·K), and a melting point of 108°C, while also exhibiting good performance stability.

[0057] In summary, this invention provides a novel method for preparing a metal thermal pad and the metal thermal pad itself, aiming to solve the "thermal barrier" problem faced by high heat flux density chips, belonging to the field of thermal interface materials. The novel metal thermal pad is made of an indium-tin binary alloy, comprising 40-70% indium and 30-60% tin by mass. The metal thermal pad is prepared through alloy melting, cold rolling, surface treatment, and die cutting. The novel metal thermal pad provided by this invention features high performance, low cost, low contact thermal resistance, and excellent stability, meeting the requirements of high-performance chips and power devices.

[0058] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0059] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a metal thermally conductive pad, characterized in that, The method for preparing the metal thermal pad includes: Step 1, Alloy preparation: Indium-tin alloy is prepared by loading 40-70% indium and 30-60% tin into a vacuum melting furnace. Step 2, cold rolling: The obtained indium-tin alloy raw material is pickled, rolled, degreased and annealed to form the material; Step 3, Surface treatment: The cold-rolled product is sent into a textured mold for surface embossing to improve the compressibility of the thermal pad and reduce contact thermal resistance. Step 4, Die-cutting: The surface-treated product is fed into a die-cutting machine and cut according to the set size and shape to obtain a metal thermal pad.

2. The method for preparing the metal thermal pad according to claim 1, characterized in that, In step one, indium and tin are filled in order of increasing melting point.

3. The method for preparing the metal thermally conductive pad according to claim 1, characterized in that, In step one, the metal melting temperature is greater than or equal to 300°C, the melting time is greater than or equal to 10 minutes, and the vacuum degree is less than or equal to 10 Pa.

4. The method for preparing the metal thermal pad according to claim 1, characterized in that, The thickness of the metal thermal pad after step two is 0.05mm to 1mm.

5. The method for preparing the metal thermally conductive pad according to claim 1, characterized in that, The thickness of the metal thermal pad after step three is 0.1mm to 1.5mm.

6. The method for preparing the metal thermally conductive pad according to claim 1, characterized in that, In step one, the purity of indium is greater than or equal to 99.99%, and the purity of tin is greater than or equal to 99.99%.

7. A metal thermally conductive pad, characterized in that, The metal thermal pad is made of an indium-tin binary alloy.

8. The metal thermal pad according to claim 7, characterized in that, The indium-tin alloy comprises 40-70% indium and 30-60% tin by mass.

9. The metal thermal pad according to claim 8, characterized in that, The thermal pad has a melting point greater than 100°C and undergoes no phase change during use.

10. The metal thermally conductive pad according to claim 9, characterized in that, The metal thermal pad is prepared using the method for preparing a metal thermal pad as described in any one of claims 1 to 6.

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