Heat sink material and preparation method thereof, and electronic packaging material

Abstract

The present invention discloses a heat sink material and its preparation method for electronic packaging materials. The preparation method includes the following steps: sequentially stacking a lower high thermal conductivity material layer, a lower low expansion coefficient material layer, an intermediate material layer, an upper low expansion coefficient material layer, and an upper high thermal conductivity material layer to prepare a prefabricated heat sink material; pressurizing the lower high thermal conductivity material layer and the upper high thermal conductivity material layer, heating the prefabricated heat sink material, and rolling to prepare a heat sink material comprising a lower high thermal conductivity layer, a lower low expansion coefficient layer, an intermediate layer, an upper low expansion coefficient layer, and an upper high thermal conductivity layer. By selecting and matching the materials and thicknesses of the different high thermal conductivity layers and low expansion coefficient layers, and combining an optimized hot pressing method and parameters, a heat sink material with high thermal conductivity and low expansion coefficient is efficiently obtained.

Description

Technical Field

[0001] The present invention relates to the field of electronic packaging materials, and in particular to a heat sink material and a preparation method thereof, as well as an electronic packaging material. Background Art

[0002] As electronic components become increasingly integrated, nanometer-scale line widths and slots allow for more electronic components to be placed on a chip. However, as these components operate, they generate significant heat. Given that chip area cannot be significantly increased, the greater the number of components on a chip, the greater the heat generated per unit area. Heat dissipation has become a major obstacle hindering the electronic component industry. In particular, to meet the demands of Moore's Law, many companies are adopting 3D stacking technology to meet chip application requirements, which in turn increases the demand for heat dissipation from electronic components.

[0003] Microelectronic packaging heat sink materials have two functions: first, they absorb heat emitted by electronic components, and second, they transfer the absorbed heat to a cooler environment, ensuring that components, assemblies, and systems operate at appropriate temperatures. However, traditional microelectronic packaging heat sink materials have limited thermal conductivity (300W / (m·K)), which cannot meet the heat dissipation requirements of higher-power chips. Furthermore, the need for multiple layers of heat sink material to be laminated by hot pressing reduces production efficiency. Summary of the Invention

[0004] Based on this, in order to improve the production efficiency and thermal conductivity of multi-layer heat sink materials, it is necessary to provide a heat sink material and a preparation method thereof, as well as an electronic packaging material.

[0005] In one aspect, the present invention provides a method for preparing a heat sink material, which comprises the following steps:

[0006] S10: stacking a lower high thermal conductivity material layer, a lower low expansion coefficient material layer, an intermediate material layer, an upper low expansion coefficient material layer and an upper high thermal conductivity material layer in sequence, wherein the thickness ratio of the lower high thermal conductivity material layer, the lower low expansion coefficient material layer, the intermediate material layer, the upper low expansion coefficient material layer and the upper high thermal conductivity material layer is (1-2):(1-2):(4-10):(1-2):(1-2), to prepare a prefabricated heat sink material;

[0007] The intermediate material layer includes an intermediate high thermal conductivity material layer and an intermediate low expansion coefficient material layer alternately stacked in sequence, the number of layers of the intermediate high thermal conductivity material layer is n, the number of layers of the intermediate low expansion coefficient material layer is m, n=m+1 and m is an integer from 0 to 3;

[0008] The thermal conductivity of the lower high thermal conductivity material, the middle high thermal conductivity material and the upper high thermal conductivity material is independently 100W / (m·K) to 500W / (m·K), and the expansion coefficient of the lower low expansion coefficient material, the middle low expansion coefficient material and the upper low expansion coefficient material is independently 6.0×10 -6 / K~8.0×10 -6 / K;

[0009] The surface roughness of the lower high thermal conductivity material, the lower low expansion coefficient material, the middle high thermal conductivity material, the middle low expansion coefficient material, the upper low expansion coefficient material and the upper high thermal conductivity material is independently 0.3 μm to 1.6 μm;

[0010] S20: Pressurizing the lower high thermal conductivity material layer and the upper high thermal conductivity material layer, heating the prefabricated heat sink material, and rolling to prepare a heat sink material having a lower high thermal conductivity layer, a lower low expansion coefficient layer, an intermediate layer, an upper low expansion coefficient layer, and an upper high thermal conductivity layer stacked in sequence.

[0011] In one embodiment, one or more of the following conditions are met:

[0012] (1) The lower high thermal conductivity material, the middle high thermal conductivity material, and the upper high thermal conductivity material are each independently selected from one or more of copper, aluminum, and silver;

[0013] (2) The lower low expansion coefficient material, the middle low expansion coefficient material, and the upper low expansion coefficient material are each independently selected from one or more of molybdenum, molybdenum-copper alloy, and tungsten-copper alloy;

[0014] (3) The thickness of the heat sink material is 0.5 mm to 3 mm.

[0015] In one embodiment, the middle low expansion coefficient material and the upper low expansion coefficient material meet one or more of the following conditions:

[0016] (1) The composition of the molybdenum-copper alloy, in terms of weight percentage, comprises 60% to 80% molybdenum and 20% to 40% copper;

[0017] (2) The composition of the tungsten-copper alloy includes 50% to 70% tungsten and 30% to 50% copper in weight percentage.

[0018] In one embodiment, one or more of the following conditions are met:

[0019] (1) m is 0, and the prefabricated heat sink material includes the lower high thermal conductivity material layer, the lower low expansion coefficient material layer, the middle high thermal conductivity material layer, the upper low expansion coefficient layer material, and the upper high thermal conductivity material layer in a thickness ratio of (1-2):(1-2):(4-6):(1-2):(1-2);

[0020] (2) m is an integer from 1 to 3, and the prefabricated heat sink material includes the lower high thermal conductivity material layer, the lower low expansion coefficient material layer, the middle high thermal conductivity material layer, the middle low expansion coefficient material layer, the upper low expansion coefficient material layer and the upper high thermal conductivity material layer with a thickness ratio of (1 to 2):(1 to 2):(3 to 7):(1 to 2):(1 to 2):(1 to 2).

[0021] In one embodiment, in step S20 , a pressure of 180 MPa to 220 MPa is applied to the lower high thermal conductivity layer and the upper high thermal conductivity layer.

[0022] In one embodiment, the heating conditions include: a heating time of 60 minutes to 120 minutes, and a heating temperature of 800° C. to 900° C.

[0023] In one embodiment, the rolling conditions include: a rolling pressure of 50 tons to 70 tons, and a rolling reduction of 40% to 60%.

[0024] In one embodiment, before step S10, the lower high thermal conductivity material layer, the lower low expansion coefficient material layer, the intermediate material layer, the upper low expansion coefficient material layer and the upper high thermal conductivity material layer are subjected to surface roughening, cleaning and drying.

[0025] Furthermore, the present invention also provides a heat sink material prepared according to the above preparation method.

[0026] Furthermore, the present invention also provides an electronic packaging material, comprising the above-mentioned heat sink material.

[0027] The above-mentioned heat sink material achieves atomic mutual penetration at the interface between different material layers by limiting the surface roughness of different high thermal conductivity layers and low expansion coefficient layers, and selects and matches the thickness, and further cooperates with optimized hot pressing methods and parameters to achieve atomic-level bonding, thereby efficiently obtaining a heat sink material with high thermal conductivity and low expansion coefficient in the high temperature zone. The above-mentioned heat sink material meets the requirement that the tube shell does not deform during brazing (silver-copper welding) at 800°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a structural diagram of a five-layer heat sink material;

[0029] Figure 2This is a structural diagram of a seven-layer heat sink material;

[0030] Figure 3 (a) is the side view and (b) is the top view of the simulation model used in thermal simulation.

[0031] Figure 4 Figure 1 shows the thermal simulation results. (a) is for the traditional CPC141, (b) is for the traditional CPC232, and (c) is provided in Example 1.

[0032] Description of reference numerals:

[0033] 10: Heat sink material, 101: Upper high thermal conductivity layer, 102: Upper low expansion coefficient layer, 103: Middle layer, 1031: First middle high thermal conductivity layer, 1032: Middle low expansion coefficient layer, 1033: Second middle high thermal conductivity layer, 104: Lower high thermal conductivity layer, 105: Lower low expansion coefficient layer, 201: Top cover, 202: Lead frame, 203: Heat sink material, 204: Solder, 205: Radiator, 206: Chip. DETAILED DESCRIPTION

[0034] The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided for the purpose of providing a more thorough and comprehensive understanding of the disclosure of the present invention. Of course, they are merely illustrative and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or arrangements discussed.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of the present invention, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0036] Unless otherwise indicated, all percentages, fractions, and ratios are calculated based on the total weight of the compositions of the present invention. Unless otherwise indicated, all masses pertaining to listed ingredients are given as active ingredients and therefore do not include solvents or by-products that may be present in commercially available materials. The term "mass percentage content" may be expressed herein using the symbol "%.

[0037] As used herein, "comprises," "includes," "contains," "has," "has" or other variations are intended to encompass non-exclusive inclusions, and no distinction is made between these terms. The term "comprising" means that other steps and ingredients that do not affect the end result may be added. The term "comprising" also encompasses the terms "consisting of" and "consisting essentially of." The compositions and methods / methods of the present invention comprise, consist of, and consist essentially of the essential elements and limitations described herein, as well as any additional or optional ingredients, components, steps, or limitations described herein. No distinction is made between the terms "efficacy," "performance," "effect," and "efficacy" herein.

[0038] The terms "preferably," "more preferably," and the like, used herein refer to embodiments of the present invention that may provide certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the present invention.

[0039] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are understood to include any and all subranges subsumed therein.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] The present invention provides a method for preparing a heat sink material, comprising the following steps:

[0042] Step S10: stacking a lower high thermal conductivity material layer, a lower low expansion coefficient material layer, an intermediate material layer, an upper low expansion coefficient material layer and an upper high thermal conductivity material layer in sequence, wherein the thickness ratio of the lower high thermal conductivity material layer, the lower low expansion coefficient material layer, the intermediate material layer, the upper low expansion coefficient material layer and the upper high thermal conductivity material layer is (1-2):(1-2):(4-10):(1-2):(1-2), to prepare a prefabricated heat sink material;

[0043] The intermediate material layer includes an intermediate high thermal conductivity material layer and an intermediate low expansion coefficient material layer alternately stacked in sequence, the number of intermediate high thermal conductivity material layers is n, the number of intermediate low expansion coefficient material layers is m, n=m+1 and m is an integer from 0 to 3;

[0044] The thermal conductivity of the lower high thermal conductivity material, the middle high thermal conductivity material and the upper high thermal conductivity material are each independently 100W / (m·K) to 500W / (m·K), and the expansion coefficient of the lower low expansion coefficient material, the middle low expansion coefficient material and the upper low expansion coefficient material are each independently 6.0x10 -6 / K~8.0x10 -6 / K,

[0045] The surface roughness of the lower high thermal conductivity material, the lower low expansion coefficient material, the middle high thermal conductivity material, the middle low expansion coefficient material, the upper low expansion coefficient material and the upper high thermal conductivity material is each independently greater than 0.3 μm.

[0046] Step S20: Pressurizing the lower high thermal conductivity material layer and the upper high thermal conductivity material layer, heating the prefabricated heat sink material, and rolling to prepare a heat sink material having a lower high thermal conductivity layer, a lower low expansion coefficient layer, an intermediate layer, an upper low expansion coefficient layer, and an upper high thermal conductivity layer stacked in sequence.

[0047] In a specific example, m is 0, and the prefabricated heat sink material includes a lower high thermal conductivity material layer, a lower low expansion coefficient material layer, an intermediate high thermal conductivity material layer, an upper low expansion coefficient material layer, and an upper high thermal conductivity material layer in a thickness ratio of (1-2):(1-2):(4-6):(1-2):(1-2). Furthermore, the prefabricated heat sink material includes a lower high thermal conductivity material layer, a lower low expansion coefficient material layer, an intermediate high thermal conductivity material layer, an upper low expansion coefficient material layer, and an upper high thermal conductivity material layer in a thickness ratio of 1:(1-2):(2-6):(1-2):1.

[0048] In a specific example, m is an integer from 1 to 3, and the prefabricated heat sink material includes a lower high thermal conductivity material layer, a lower low expansion coefficient material layer, a middle high thermal conductivity material layer, a middle low expansion coefficient material layer, an upper low expansion coefficient material layer, and an upper high thermal conductivity material layer with a thickness ratio of 1:(1-2):(3-7):(1-2):(1-2):1.

[0049] Preferably, m is an integer from 0 to 1. It can be understood that m is 0 or 1.

[0050] In a specific example, the thickness of the heat sink material is 0.5 mm to 3 mm. It is understandable that the thickness of the heat sink material can be, but is not limited to, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, or 3 mm.

[0051] In a specific example, the lower high thermal conductivity material, the middle high thermal conductivity material, and the upper high thermal conductivity material are each independently selected from one or more of copper, aluminum, and silver.

[0052] In a specific example, the lower low expansion coefficient material, the middle low expansion coefficient material, and the upper low expansion coefficient material are each independently selected from one or more of molybdenum, molybdenum-copper alloy, and tungsten-copper alloy.

[0053] Furthermore, the composition of the molybdenum-copper alloy includes, by weight, 60% to 80% molybdenum and 20% to 40% copper. It is understood that the molybdenum-copper alloy may be, but is not limited to, 60% molybdenum and 40% copper, 65% molybdenum and 35% copper, 70% molybdenum and 30% copper, 75% molybdenum and 25% copper, or 80% molybdenum and 20% copper.

[0054] Furthermore, the composition of the tungsten copper alloy includes 50% to 70% tungsten and 30% to 50% copper by weight. It is understood that the tungsten copper alloy may be, but is not limited to, composed of 50% tungsten and 50% copper by weight, or 55% tungsten and 45% copper, or 60% tungsten and 40% copper, or 65% tungsten and 35% copper, or 70% tungsten and 30% copper by weight.

[0055] In a specific example, a pressure of 180 MPa to 220 MPa is applied to the lower high thermal conductivity material layer and the upper high thermal conductivity material layer.

[0056] It can be understood that the above pressure can be but is not limited to 180 MPa, 190 MPa, 200 MPa, 210 MPa or 220 MPa.

[0057] In a specific example, the heating conditions include: a heating time of 60 minutes to 120 minutes.

[0058] Furthermore, the heating time may be, but is not limited to, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes or 120 minutes.

[0059] In a specific example, the heating conditions include: a heating temperature of 800°C to 900°C.

[0060] Furthermore, the heating temperature may be, but is not limited to, 800°C, 810°C, 820°C, 830°C, 840°C, 850°C, 860°C, 870°C, 880°C, 890°C or 900°C.

[0061] Furthermore, the heating process is carried out in an inert gas atmosphere.

[0062] In a specific example, the rolling conditions include: a rolling pressure of 50 tons to 70 tons, and a rolling reduction of 40% to 60%.

[0063] Further, the rolling pressure may be, but is not limited to, 50 tons, 55 tons, 60 tons, 65 tons or 70 tons.

[0064] Furthermore, the rolling reduction may be, but is not limited to, 40%, 45%, 50%, 55% or 60%.

[0065] It can be understood that the above-mentioned rolling further includes an annealing step, and the annealing conditions include a temperature of 750° C. to 900° C. and an annealing time of 2 hours to 5 hours.

[0066] Furthermore, the annealing temperature may be, but is not limited to, 750°C, 800°C, 850°C or 900°C.

[0067] Furthermore, the annealing time may not be limited to 2 hours, 3 hours, 4 hours or 5 hours.

[0068] In a specific example, before step S10, the lower high thermal conductivity material layer, the lower low expansion coefficient material layer, the intermediate material layer, the upper low expansion coefficient material layer and the upper high thermal conductivity material layer are subjected to surface roughening, cleaning and drying steps.

[0069] In a specific example, the surface roughening conditions include using 100# to 200# glass sand and a pressure of 1kg to 2kg.

[0070] Furthermore, surface roughening can achieve the removal of the oxide layer on the surface of the material layer, and the surface roughening method can be, but is not limited to, sandblasting and grinding.

[0071] It can be understood that the cleaning solution can be but is not limited to water.

[0072] In a specific example, when m is 0, such as Figure 1 The heat sink material 10 shown in FIG. 1 has a five-layer structure, and the middle material layer 103 is the middle high thermal conductivity layer. When m is 1, as shown in FIG. Figure 2 The heat sink material 10 shown has a seven-layer structure, and the middle material layer 103 includes a first middle high thermal conductivity layer 1031 , a middle low expansion coefficient layer 1032 and a second middle high thermal conductivity layer 1033 .

[0073] Furthermore, the present invention also provides a heat sink material 10, which is prepared according to the above preparation method.

[0074] Furthermore, the present invention also provides an electronic packaging material, comprising the above-mentioned heat sink material 10 .

[0075] The above-mentioned heat sink material achieves atomic mutual penetration at the interface between different material layers by limiting the surface roughness of different high thermal conductivity layers and low expansion coefficient layers, and selects and matches the thickness, and further cooperates with optimized hot pressing methods and parameters to achieve atomic-level bonding, thereby efficiently obtaining a heat sink material with high thermal conductivity and low expansion coefficient in the high temperature zone. The above-mentioned heat sink material meets the requirement that the tube shell does not deform during brazing (silver-copper welding) at 800°C.

[0076] The heat sink material and its preparation method of the present invention are further described in detail below with reference to specific examples. Unless otherwise specified, the raw materials used in the following examples are all commercially available products.

[0077] Example 1

[0078] (1) Prepare a 1.0 mm thick heat sink material with 5 layers. The high thermal conductivity layer is made of oxygen-free copper and the low expansion coefficient layer is made of molybdenum copper. Molybdenum copper consists of 70% molybdenum and 30% copper by mass. Its thermal conductivity is 352w / (m*k) and its thermal expansion coefficient is 7.0x10 -6 / / K

[0079] (2) Two pieces of 0.15 mm oxygen-free copper, one piece of 0.90 mm oxygen-free copper, and two pieces of 0.15 mm molybdenum copper were cleaned in a pure water environment using an ultrasonic cleaner and then dried using an air shear dryer;

[0080] (3) Then, 0.15 mm oxygen-free copper, 0.15 mm molybdenum copper, 0.90 mm oxygen-free copper, 0.15 mm molybdenum copper, and 0.15 mm oxygen-free copper are stacked in sequence and placed in a customized high-temperature and high-pressure resistant fixture;

[0081] (4) The fixture is then placed in a custom-made heating furnace, inert gas is introduced, and a pressure of 200 MPa is evenly applied to both sides of the fixture. The heating temperature is 850°C and the heating time is 60 minutes.

[0082] (5) After heating, the blank was rolled to the required thickness of 1 mm, wherein the rolling conditions included a rolling pressure of 60 tons and a reduction of 40%, followed by annealing at 850°C for 3 hours.

[0083] Example 2

[0084] (1) Prepare a 0.8 mm thick heat sink material with 5 layers. The high thermal conductivity layer material is oxygen-free copper, and the low expansion coefficient layer material is tungsten copper. Tungsten copper is composed of 60% tungsten and 40% copper by mass. Its thermal conductivity is 353w / (m*k) and the thermal expansion coefficient is 7.53x10 -6 / K

[0085] (2) Two pieces of 0.2 mm oxygen-free copper, one piece of 0.4 mm oxygen-free copper, and two pieces of 0.2 mm tungsten copper were cleaned in a pure water environment using an ultrasonic cleaner and then dried using an air shear dryer;

[0086] (3) Then, 0.2 mm oxygen-free copper, 0.2 mm tungsten copper, 0.4 mm oxygen-free copper, 0.2 mm tungsten copper, and 0.2 mm oxygen-free copper are stacked in sequence and placed in a customized high-temperature and high-pressure resistant fixture;

[0087] (4) The fixture is then placed in a custom-made heating furnace, inert gas is introduced, and a pressure of 180 MPa is evenly applied to both sides of the fixture. The heating temperature is 880°C and the heating time is 80 minutes.

[0088] (5) After heating, the blank was rolled to the required thickness of 0.8 mm, wherein the rolling conditions included a rolling pressure of 70 tons and a reduction of 50%, followed by annealing at 880° C. for 4 hours.

[0089] Example 3

[0090] (1) Prepare a 7-layer 2.0 mm thick heat sink material. The high thermal conductivity layer material is oxygen-free copper, and the low expansion coefficient layer material is molybdenum copper. Molybdenum copper is composed of 70% molybdenum and 30% copper by mass. Its thermal conductivity is 360w / (m*k) and the thermal expansion coefficient is 7.0x10 -6 / / K

[0091] (2) Two pieces of 0.3 mm oxygen-free copper, two pieces of 1.2 mm oxygen-free copper, and three pieces of 0.3 mm molybdenum copper were cleaned in a pure water environment using an ultrasonic cleaner and then dried using an air shear dryer;

[0092] (3) Then, 0.3 mm oxygen-free copper, 0.3 mm molybdenum copper, 1.2 mm oxygen-free copper, 0.3 mm molybdenum copper, 1.2 mm oxygen-free copper, 0.3 mm molybdenum copper, and 0.3 mm oxygen-free copper are stacked in sequence and placed in a customized high-temperature and high-pressure resistant fixture;

[0093] (4) The fixture is then placed in a custom-made heating furnace, inert gas is introduced, and a pressure of 220 MPa is evenly applied to both sides of the fixture. The heating temperature is 880°C and the heating time is 80 minutes.

[0094] (5) After heating, the blank was rolled to the required thickness of 2 mm, wherein the rolling conditions included a rolling pressure of 50 tons and a reduction of 40%, followed by annealing at 880°C for 4 hours.

[0095] Example 1 Example 2 Example 3 Number of layers 5 5 7 Thickness ratio 1:1:6:1:1 1:1:2:1:1 1:1:4:1:4:1:1 High thermal conductivity layer material Mo70Cu30 W60Cu40 Mo70Cu30 Low expansion coefficient materials oxygen-free copper oxygen-free copper oxygen-free copper Pressurization 200MPa 180MPa 220MPa Heating temperature 850℃ 880℃ 880℃ Heating time 60min 80 minutes 80 minutes Annealing temperature 850℃ 880℃ 880℃ Annealing time 3 hours 4 hours 4 hours Rolling conditions 60 tons, 40% reduction 70 tons, 50% reduction 50 tons, 40% reduction Heat sink material thickness 1.0mm 0.8mm 2.0mm

[0096] Detection method:

[0097] 1. Thermal conductivity test

[0098] Test instrument: NETZSCH LFA467- Thermal Conductivity Tester

[0099] Test principle: ASTM E 1461: Flash method for thermal diffusivity

[0100] The test results are shown in the following table:

[0101] Example 1 Example 2 Example 3 Test temperature 25℃ 25℃ 25℃ Thermal diffusivity mm2s 103 102 104 Specific heat capacity J / g*K 0.376 0.369 0.381 <![CDATA[Density g / cm 3 > 9.11 9.21 9.11 Thermal conductivity W / (m·K) 352.81208 353.44296 360.97464

[0102] 2. Brazing flatness test

[0103] Test method: Ceramic shell silver copper brazing process (temperature 800 degrees Celsius)

[0104] Inspection equipment: KEYENCE VR-5000 3D profile measuring instrument

[0105] The test results are shown in the following table:

[0106] Example 1 Example 2 Example 3 Flatness <25μm <h2 style=";text-align:left;direction:ltr"><25um<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"><25um<h2 style=";text-align:left;direction:ltr">

[0107] 3. Thermal simulation

[0108] 1) Using simulation software, refer to the actual packaging form and establish a simulation model such as Figure 3 shown.

[0109] 2) Under the same test conditions, using the thermal flow field cloud map, compare the different models of mainstream heat sinks on the market (CPC141 and CPC232), the heat transfer is as follows Figure 4 The heat flow field density is shown in the following table.

[0110]

[0111] The simulation results show that the heat sink material provided by the present invention has a wider heat distribution in the heat flow field cloud diagram compared to traditional flanges, resulting in a reduction in the amount of heat per unit cross-sectional area. The numerical value represents the lowest maximum value of the heat flow field density, indicating that the increase in the thermal conductivity of the flange is conducive to more uniform heat transfer downward, avoiding the formation of a "hot spot" in a certain area, avoiding affecting the heat distribution of adjacent chips and causing chip performance degradation.

[0112] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0113] The embodiments described above only express several implementation methods of the present invention, which are convenient for understanding the technical solutions of the present invention in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several variations and improvements can be made, which all fall within the scope of protection of the present invention. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided by the present invention are all within the scope of protection of the claims attached to the present invention. Therefore, the scope of protection of the patent of the present invention shall be based on the content of the attached claims, and the description and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing a heat sink material, characterized in that: The following steps are involved: S10: stacking a lower high thermal conductivity material layer, a lower low expansion coefficient material layer, an intermediate material layer, an upper low expansion coefficient material layer and an upper high thermal conductivity material layer in sequence, wherein the thickness ratio of the lower high thermal conductivity material layer, the lower low expansion coefficient material layer, the intermediate material layer, the upper low expansion coefficient material layer and the upper high thermal conductivity material layer is (1-2):(1-2):(4-10):(1-2):(1-2), to prepare a prefabricated heat sink material; The intermediate material layer includes an intermediate high thermal conductivity material layer and an intermediate low expansion coefficient material layer alternately stacked in sequence, the number of layers of the intermediate high thermal conductivity material layer is n, the number of layers of the intermediate low expansion coefficient material layer is m, n=m+1 and m is an integer from 0 to 3; The lower high thermal conductivity material, the middle high thermal conductivity material and the upper high thermal conductivity material are copper, and the expansion coefficients of the lower low expansion coefficient material, the middle low expansion coefficient material and the upper low expansion coefficient material are each independently 6.0×10 -6 / K~8.0×10 -6 / K, the lower low expansion coefficient material, the middle low expansion coefficient material and the upper low expansion coefficient material are each independently selected from a molybdenum-copper alloy or a tungsten-copper alloy, the composition of the tungsten-copper alloy, by weight percentage, includes 50% to 70% of tungsten and 30% to 50% of copper, and the composition of the molybdenum-copper alloy, by weight percentage, includes 60% to 80% of molybdenum and 20% to 40% of copper; The surface roughness of the lower high thermal conductivity material, the lower low expansion coefficient material, the middle high thermal conductivity material, the middle low expansion coefficient material, the upper low expansion coefficient material and the upper high thermal conductivity material is independently 0.3 μm to 1.6 μm; S20: Pressurizing the lower high thermal conductivity material layer and the upper high thermal conductivity material layer, heating the prefabricated heat sink material, and rolling to prepare a heat sink material having a lower high thermal conductivity layer, a lower low expansion coefficient layer, an intermediate layer, an upper low expansion coefficient layer, and an upper high thermal conductivity layer stacked in sequence.

2. The preparation method according to claim 1, wherein The thickness of the heat sink material is 0.5 mm to 3 mm.

3. The preparation method according to claim 1, wherein m is 0, and the prefabricated heat sink material includes the lower high thermal conductivity material layer, the lower low expansion coefficient material layer, the middle high thermal conductivity material layer, the upper low expansion coefficient material layer and the upper high thermal conductivity material layer with a thickness ratio of (1~2):(1~2):(4~6):(1~2):(1~2).

4. The preparation method according to claim 1, wherein m is an integer from 1 to 3, and the prefabricated heat sink material includes the lower high thermal conductivity material layer, the lower low expansion coefficient material layer, the middle high thermal conductivity material layer, the middle low expansion coefficient material layer, the upper low expansion coefficient material layer and the upper high thermal conductivity material layer with a thickness ratio of (1 to 2):(1 to 2):(3 to 7):(1 to 2):(1 to 2):(1 to 2).

5. The preparation method according to claim 1, wherein In step S20 , a pressure of 180 MPa to 220 MPa is applied to the lower high thermal conductivity layer and the upper high thermal conductivity layer.

6. The preparation method according to claim 1, wherein The heating conditions include: a heating time of 60 minutes to 120 minutes and a heating temperature of 800° C. to 900° C.

7. The preparation method according to claim 1, wherein The rolling conditions include: a rolling pressure of 50 tons to 70 tons, and a rolling reduction of 40% to 60%.

8. The preparation method according to any one of claims 1 to 7, characterized in that Before step S10 , the lower high thermal conductivity material layer, the lower low expansion coefficient material layer, the intermediate material layer, the upper low expansion coefficient material layer and the upper high thermal conductivity material layer are subjected to surface roughening, cleaning and drying.

9. A heat sink material, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 8.

10. An electronic packaging material, characterized in that: The heat sink material according to claim 9 is included.

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