Gradient heat sink composite material and preparation method thereof

Abstract

The invention discloses a gradient heat sink composite material and a preparation method thereof. The preparation method comprises the following steps: obtaining a framework material assembly with the density changing in a gradient manner; and covering the framework material assembly with a copper sheet, and performing copper infiltration sintering at 1400-1500 DEG C in a hydrogen atmosphere to obtain the gradient heat sink composite material. The gradient heat sink composite material obtained by the invention has the function of being effectively matched with chips with various different thermal expansion coefficients at the same time, and meets the urgent requirements of the high-power and highly-integrated electronic packaging field on efficient heat dissipation materials.

Description

Technical Field

[0001] The present invention relates to the technical field of heat sink materials, in particular to the technical field of multi-component heat sink composite materials. Background Art

[0002] With the improvement of electronic packaging technology and computer supercomputing technology, semiconductor instruments tend to develop towards ultra-miniaturization. The integration requirements of microelectronic integrated devices are getting higher and higher, and the current passing through them is getting larger and larger. The frequency of the current is also increasing, which is accompanied by a significant increase in the heat generation of the device, which poses an unprecedented challenge to the heat dissipation system. At the same time, the power used by electronic components is also continuing to rise, further exacerbating the complexity of the heat dissipation problem. In addition, in microelectronic integrated circuits and high-power rectifier devices, due to the mismatch of thermal expansion coefficients between materials, thermal stress and thermal fatigue problems have become increasingly prominent, which has become the main cause of failure of microelectronic circuits and devices, and has seriously restricted the performance and reliability of electronic equipment.

[0003] At present, the heat sink materials used in the electronic packaging field are mostly single-component, such as Mo70Cu or W80Cu, which can only form a single matching relationship with chips with specific thermal expansion coefficients, and cannot be matched with different types of chips with large differences in thermal expansion coefficients. Therefore, it is impossible to meet the needs of different types of chips for heat dissipation materials at the same time.

[0004] In view of the above technical problems, an intuitive solution is to use a variety of heat sink composite materials together, but this method will undoubtedly increase the size and complexity of microelectronic integrated devices, which is not conducive to the miniaturization and integration of devices. Summary of the invention

[0005] In view of the defects of the prior art, the purpose of the present invention is to propose a new gradient heat sink composite material and a preparation method thereof, which can accurately control the density and ratio of materials with the same composition in the thickness direction to present a gradient distribution, so that the material has the function of effectively matching with multiple chips with different thermal expansion coefficients at the same time, thereby meeting the urgent demand for high-efficiency heat dissipation materials in the field of high-power and highly integrated electronic packaging.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing a gradient heat sink composite material, comprising:

[0008] Obtaining a blank of a skeleton material assembly having a gradient density change;

[0009] Covering a metal sheet on the blank of the skeleton material assembly, and performing infiltration sintering on the metal sheet at 1400-1500° C. in a hydrogen atmosphere to obtain the gradient heat sink composite material;

[0010] Wherein, the skeleton material is selected from one or more of molybdenum, tungsten, silicon carbide, aluminum oxide, zirconium tungstate and silicon, and the metal sheet is selected from one or more of copper, silver, aluminum and magnesium.

[0011] According to some preferred embodiments of the present invention, obtaining the blank of the skeleton material assembly comprises:

[0012] The powder of the skeleton material is grouped according to the density distribution of the skeleton material assembly, one density corresponds to one group, and then the powders are weighed according to the mass requirements corresponding to the density, and pressed into blanks respectively to obtain green compact layers with different densities;

[0013] The green sheets with different densities are stacked in sequence according to the density distribution of the skeleton material assembly to obtain the green sheets of the skeleton material assembly.

[0014] According to some preferred embodiments of the present invention, the thickness of the green compact layers with different densities is 1 to 10 mm, and the thickness can be equal or different, and can be controlled by adjusting the quality of the skeleton material of the green compact layers.

[0015] According to some preferred embodiments of the present invention, the green compact is formed by compression molding using a 50-100 mm×50-100 mm mold.

[0016] According to some preferred embodiments of the present invention, obtaining the blank of the skeleton material assembly comprises:

[0017] The powder of the framework material is grouped according to the density of the framework material assembly, with one density corresponding to one group, and then weighed respectively according to the mass requirements corresponding to the density to obtain several groups of powder of the framework material with different masses;

[0018] According to the density distribution of the skeleton material assembly, the skeleton material powder having a mass corresponding to the lowest layer density, i.e., the first layer density, is pressed and formed to form a first pressed green sheet layer, thereby obtaining a first green sheet;

[0019] Adding a powder of a skeleton material having a mass corresponding to the density of the second layer of the skeleton material assembly to the first blank, continuing to press and form a second pressed layer, and obtaining a second blank including the first pressed layer and the second pressed layer;

[0020] The above process of adding the skeleton material powder and continuing the pressing and forming is repeated until an integral blank of the skeleton material assembly corresponding to the density distribution of the skeleton material assembly is obtained, namely, the blank of the skeleton material assembly.

[0021] According to some preferred embodiments of the present invention, the thickness of each green compact layer is 1 to 10 mm, and the thicknesses may be equal or unequal, and may be controlled by adjusting the mass of the skeleton material of each green compact layer.

[0022] According to some preferred embodiments of the present invention, each green compact layer is pressed by a 50-100 mm×50-100 mm mold.

[0023] According to some preferred embodiments of the present invention, the holding time of the infiltration sintering is 1 to 3 hours.

[0024] According to some preferred embodiments of the present invention, the skeleton material is selected from molybdenum, the metal sheet is selected from copper sheet, the skeleton material assembly includes a first molybdenum skeleton, a second molybdenum skeleton and a third molybdenum skeleton with a density gradient change, and the mass ratio of the skeleton material assembly to the copper sheet is 1 to 4:1.

[0025] The present invention has the following beneficial effects:

[0026] The preparation method of the present invention combines compacts of different densities and then performs infiltration sintering on the combined body to obtain a heat sink composite material with components in a layered gradient distribution, thereby solving the problem that a single-component heat sink material is not applicable to two or more chips.

[0027] The preparation method of the present invention can achieve the regulation of the thermal expansion coefficient of the composite material on the upper and lower surfaces and in the entire thickness direction by accurately regulating the skeleton density of each laminated blank, so that the obtained heat sink composite material can achieve excellent matching with a variety of chips, significantly improving the applicability and compatibility of the material;

[0028] The gradient heat sink composite material obtained by the present invention is composed of skeleton materials of different densities melt-infiltrated and combined, and the components on the upper and lower surfaces are different, and the component distribution in the thickness direction is also different. Therefore, the thermal expansion coefficients on the upper and lower surfaces are different, and the thermal expansion coefficient in the thickness direction presents a gradient change, which can realize simultaneous matching of chips with multiple different thermal expansion coefficients at different positions on the upper and lower surfaces or in the thickness direction.

[0029] Compared with a single-component heat sink composite material, the gradient heat sink composite material obtained by the present invention has higher thermal conductivity and better heat dissipation performance, and can effectively meet the stringent requirements for heat dissipation capacity in the field of high-power and high-integration electronic packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the preparation process of the single compact preparation method used in Example 1.

[0031] Figure 2This is a schematic diagram of the preparation process of the step-by-step continuous pressing method used in Example 2. DETAILED DESCRIPTION

[0032] The technical scheme of the present invention will be further described below in conjunction with the embodiments and drawings of the present invention. The embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] Example 1

[0034] See attached Figure 1 , a layered Mo80Cu / Mo70Cu / Mo50Cu heat sink composite material was prepared by the following steps:

[0035] (1) Selecting a 80 mm × 60 mm pressing die, adjusting the pressure of the press, 191 g of molybdenum powder, 165 g of molybdenum powder, and 115 g of molybdenum powder were pressed into green compacts with a thickness of 5 mm, respectively, to obtain green compact skeletons of Mo80Cu, Mo70Cu, and Mo50Cu;

[0036] (2) stacking the pressed green skeletons of Mo50Cu, Mo70Cu, and Mo80Cu in sequence from bottom to top to obtain a stacked skeleton;

[0037] (3) A copper sheet weighing 286 g was covered on the upper surface of the stacked skeleton and copper infiltration sintering was performed at 1400 °C for 2 h in a hydrogen atmosphere. Due to the capillary effect, the molten copper penetrated into the molybdenum pressed green sheet skeleton to form a Mo80Cu / Mo70Cu / Mo50Cu layered molybdenum-copper alloy with a gradient composition.

[0038] Example 2

[0039] See attached Figure 2 , a layered Mo50Cu / Mo60Cu / Mo70Cu heat sink composite material was prepared by the following steps.

[0040] (1) Select a 70 mm × 50 mm pressing die, and adjust the pressure of the press to press 90 g of molybdenum powder into a 3 mm thick green compact, corresponding to a Mo70Cu green compact skeleton;

[0041] (2) Add 61 g of molybdenum powder to the Mo70Cu green compact skeleton, and then adjust the pressure of the press to press the added 61 g of molybdenum powder into a 3 mm thick green compact, i.e., a Mo60Cu green compact skeleton;

[0042] (3) Add 51 g of molybdenum powder to the Mo60Cu green compact skeleton, and then adjust the pressure of the press to press the added 51 g of molybdenum powder into a 3 mm thick green compact, i.e., a Mo50Cu green compact skeleton;

[0043] (4) The entire billet is demolded, and a copper sheet with a mass of 157 g is covered on the surface of the billet. The billet is copper-infiltrated and sintered at 1400°C for 2 h in a hydrogen atmosphere to form a Mo50Cu / Mo60Cu / Mo70Cu layered molybdenum-copper alloy with a gradient composition.

[0044] It should be noted that the above is only a preferred embodiment of the present invention, which should not limit the protection scope of the technical solution of the present invention. Any modification of the technical solution recorded in the above embodiments and equivalent replacement of technical features by ordinary technicians in the field within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a gradient heat sink composite material, characterized in that: It includes: Obtaining a blank of a skeleton material assembly having a gradient density change; Covering a metal sheet on the blank of the skeleton material assembly, and performing infiltration sintering on the metal sheet at 1400-1500° C. in a hydrogen atmosphere to obtain the gradient heat sink composite material; Wherein, the skeleton material is selected from one or more of molybdenum, tungsten, silicon carbide, aluminum oxide, zirconium tungstate and silicon, and the metal sheet is selected from one or more of copper, silver, aluminum and magnesium.

2. The preparation method according to claim 1, characterized in that: The blank of the skeleton material assembly is obtained by: The powder of the skeleton material is grouped according to the density distribution of the skeleton material assembly, one density corresponds to one group, and then the powders are weighed according to the mass requirements corresponding to the density, and pressed into blanks respectively to obtain green compact layers with different densities; The green sheets with different densities are stacked in sequence according to the density distribution of the skeleton material assembly to obtain the green sheets of the skeleton material assembly.

3. The preparation method according to claim 2, characterized in that: The thickness of the green compact layers with different densities is 1 to 10 mm.

4. The preparation method according to claim 2, characterized in that: The compact is pressed and formed by a 50-100mm×50-100mm mold.

5. The preparation method according to claim 1, characterized in that: The blank of the skeleton material assembly is obtained by: The powder of the framework material is grouped according to the density of the framework material assembly, with one density corresponding to one group, and then weighed respectively according to the mass requirements corresponding to the density to obtain several groups of powder of the framework material with different masses; According to the density distribution of the skeleton material assembly, the skeleton material powder having a mass corresponding to the lowest layer density, i.e., the first layer density, is pressed and formed to form a first pressed green sheet layer, thereby obtaining a first green sheet; Adding a powder of a skeleton material having a mass corresponding to the density of the second layer of the skeleton material assembly to the first blank, continuing to press and form a second pressed layer, and obtaining a second blank including the first pressed layer and the second pressed layer; The above process of adding the skeleton material powder and continuing the pressing and forming is repeated until an integral blank of the skeleton material assembly corresponding to the density distribution of the skeleton material assembly is obtained, namely, the blank of the skeleton material assembly.

6. The preparation method according to claim 5, characterized in that: in, The thickness of each green compact layer is 1 to 10 mm.

7. The preparation method according to claim 5, characterized in that: in, Each green sheet layer is pressed and formed by a 50-100mm×50-100mm die.

8. The preparation method according to claim 1, characterized in that: The heat preservation time of the infiltration sintering is 1 to 3 hours.

9. The preparation method according to claim 1, characterized in that: The skeleton material is selected from molybdenum, the metal sheet is selected from copper sheet, the skeleton material assembly includes a first molybdenum skeleton, a second molybdenum skeleton and a third molybdenum skeleton with gradient density, and the mass ratio of the skeleton material assembly to the copper sheet is 1 to 4:

1.

10. The gradient heat sink composite material prepared by the preparation method according to any one of claims 1 to 9.

Images