A method and apparatus for forming micro-texture on the surface of an IC heat sink

Abstract

The application provides an IC heat sink surface micro-texture forming method and device, and relates to the field of electronic device manufacturing. The application puts aluminum alloy into a stamping die for stamping forming to obtain a workpiece with micro-texture on one side; the workpiece is transferred to a PVD chamber, vacuum is drawn, inert gas is introduced, a sputtering power source is turned on, and a titanium oxide coating and a PTFE-silica coating are sputter deposited on the side with micro-texture in sequence; the sputtering power source is turned off, and the workpiece is discharged, thereby obtaining an IC heat sink; wherein the aluminum alloy contains, in terms of weight percentage, Si 2%-3%, Cu 0.2%-0.4%, Ti 0.05%-0.1%, B 0.1%-0.5%, Sc 0.03%-0.08%, Sr 0.02%-0.05%, unavoidable impurities <0.1%, and the balance is aluminum. The IC heat sink prepared by the application has good heat conduction performance, can accelerate heat transfer, and enhance the heat dissipation effect, and the sputtering functional coating has high bonding strength with the aluminum alloy workpiece and good stability.

Description

Technical Field

[0001] This application relates to the field of electronic device manufacturing, and in particular to a method and apparatus for micro-weaving on the surface of an IC heat sink. Background Technology

[0002] With the advancement of technology, electronic products are gradually becoming lighter, thinner, shorter, and smaller. However, the high heat generated by miniaturized electronic components operating at high speeds often shortens the lifespan of these products. Therefore, solving the heat dissipation problem has always been a top priority for the industry. Heat sinks are a heat dissipation technology for CPUs (Central Processing Units) or GPUs (Graphics Processing Units). They efficiently transfer heat to cooling systems such as heat sinks and fans, significantly enhancing hardware performance and stability, and effectively preventing damage caused by overheating.

[0003] Commonly available vapor chambers are typically made of metals or alloys such as copper, stainless steel, and aluminum. Their coefficients of thermal expansion differ significantly from those of the chip, resulting in poor stability and difficulty in meeting the heat dissipation requirements of high heat flux density chips. Patent CN109715854A discloses the use of silica-derived CNT aerogel in the coating of a vapor chamber, sprayed onto the inner wall of the vapor chamber to enhance heat transfer and dissipation performance. Patent CN209710562U discloses a vapor chamber heat sink that coats several layers of graphene onto the heat dissipation surface of an aluminum alloy substrate, giving it excellent heat dissipation and thermal radiation performance. While coating the surface of a vapor chamber with a functional layer can improve heat dissipation, this method generally requires post-processing, resulting in significant pollution, low production efficiency, poor adhesion between the coating and the substrate, and a tendency for the surface functional layer to crack and peel off.

[0004] Therefore, there is currently a lack of IC heat sinks with good heat dissipation performance and good adhesion between the coating and the substrate. Summary of the Invention

[0005] The purpose of this application is to provide a method and apparatus for micro-weaving on the surface of an IC heat sink, addressing the shortcomings of existing technologies.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0007] On the one hand, a method for microtexturing the surface of an IC heat sink is provided, comprising the following steps:

[0008] S1. The aluminum alloy is placed into a stamping die for stamping to obtain a workpiece with a micro-texture on one side;

[0009] S2. Transfer the workpiece to the physical vapor deposition (PVD) chamber, evacuate, introduce inert gas, turn on the sputtering power supply, and sequentially sputter and deposit a titanium oxide coating and a PTFE-silica coating on the side with microtexture.

[0010] S3. Turn off the sputtering power supply, unload the material, and you will get the product.

[0011] Furthermore, the lower die forming surface of the stamping die has a microtexture, which is formed by micro-nano processing technology such as femtosecond laser, micro-milling or LIGA technology.

[0012] Optionally, the microtexture of the lower mold forming surface of the mold determines the surface structure of the heat exchanger. This application utilizes femtosecond laser, micromilling, or LIGA technology to process the required array of micropits or grooves on the lower mold forming surface of the mold, thereby forming a specific microtexture on the resulting heat exchanger surface, improving heat dissipation performance, and also increasing roughness, thereby enhancing the interfacial adhesion of the functional coating.

[0013] Further, in step S1, the aluminum alloy, by weight percentage, comprises: Si 2%–3%, Cu 0.2%–0.4%, Ti 0.05%–0.1%, B 0.1%–0.5%, Sc 0.03%–0.08%, Sr 0.02%–0.05%, unavoidable impurities <0.1%, and the balance being aluminum.

[0014] Preferably, in the aluminum alloy, the ratio of the total weight of Sr and Sc to the weight of Si satisfies: 0.04 < (Sr + Sc) / Si < 0.06, and the endpoint values ​​of 0.04 and 0.06 cannot be obtained.

[0015] Furthermore, the aluminum alloy is prepared by the following method:

[0016] (1) According to the formula, add pure aluminum into the melting furnace first, and melt at 680-700℃;

[0017] (2) Heat to 720-740℃, add the remaining components, and continue smelting to obtain an alloy liquid;

[0018] (3) Refine with refining agent;

[0019] (4) The temperature of the alloy liquid is controlled at 680-700℃ and poured into the die casting machine for die casting to obtain aluminum alloy.

[0020] Optionally, in step (3), the refining agent is a sodium-free refining agent, and the amount of sodium-free refining agent used is 0.2 to 0.3% of the total weight of the metal in the furnace.

[0021] Optionally, in step (3), the refining temperature is 710-740℃ and the time is 20-30min.

[0022] Currently, most vapor chambers on the market are made of copper. Pure copper and copper alloys have high thermal conductivity, but their cost is also high. Compared to pure copper, aluminum alloys are less expensive, but their thermal conductivity is generally no higher than 200 W / (m·K), limiting the application of aluminum alloy vapor chambers. This application uses an aluminum alloy containing Si, Cu, Ti, B, Sc, and Sr to produce IC vapor chambers, which have high strength, good toughness, and a thermal conductivity higher than 200 W / (m·K). In particular, by adding a certain amount of Sr and Sc to the aluminum alloy and adjusting the ratio of Sr and Sc content to Si, the thermal conductivity of the aluminum alloy can reach over 250 W / (m·K), giving the IC vapor chamber excellent heat dissipation performance. It also increases the adhesion between the aluminum alloy and the surface sputtered coating, enhancing stability. Adding Sr and Sc to aluminum alloys can play a certain role in modification, removing slag from the alloy liquid and further refining the grains, thus playing a certain strengthening role. However, excessive Sr and Sc content can lead to overly fine grains, which in turn reduces thermal conductivity and causes defects in the alloy material during subsequent stamping.

[0023] Further, in step S1, the stamping process is as follows:

[0024] (1) Heat the aluminum alloy to 480-500℃, hold for 0.5-2 hours, and then cool to 50-55℃;

[0025] (2) Preheat the mold to 45-50°C, and then coat the mold surface and the aluminum alloy surface with stamping oil;

[0026] (3) Place the mold into the mold for pre-stamping. The pre-stamping conditions are: temperature 75-85℃, drawing speed 0.15-0.3mm / s, blank holder force 2-3N / mm. 2 After pre-stamping, cool to 50-55℃;

[0027] (4) Perform re-stamping. The re-stamping conditions are: temperature 250-270℃, drawing speed 0.4-0.5mm / s, blank holder force 4-5N / mm. 2 ;

[0028] (5) After the stamping is completed, cool to room temperature and clean to remove the stamping oil from the surface.

[0029] Optionally, the stamping oil comprises the following components by weight: 80-90 parts base oil, 3-5 parts isoparaffin solvent oil, 3-5 parts 1,3,5-cyclohexanetriethanol, 1-3 parts stearoylbenzoyl, 2-5 parts fatty alcohol polyoxyethylene ether, and 0.5-2 parts graphite emulsion.

[0030] Optionally, the base oil is selected from low viscosity base oils, preferably 150N base oil or diisooctyl adipate.

[0031] Optionally, the fatty alcohol carbon chain in the fatty alcohol polyoxyethylene ether is 9-12 and the EO number is 3 or 4.

[0032] Optionally, the isoparaffin solvent oil is known to those skilled in the art and is commercially available.

[0033] The use of stamping oil is beneficial for meeting product and surface precision requirements and protecting equipment. However, conventional stamping oils, under high temperatures, form an oil film on the aluminum alloy surface and within surface pores, which cannot be completely removed, affecting the heat dissipation performance of the heat exchanger. The stamping oil provided in this application has a good corrosion inhibition effect on aluminum alloy stamping. During use, it can be evenly sprayed onto the aluminum alloy surface to form a stable lubricating film, and effectively acts on the contact surface between the stamping die and the workpiece, reducing scratches and wear on the workpiece surface and improving the surface quality of the stamped parts. This stamping oil also has good flushing properties, preventing residues on the workpiece surface from affecting its heat dissipation performance. In addition, this application pre-pressurizes at a low temperature before high-temperature stamping, which can avoid internal defects caused by direct high-temperature stamping, maintain the uniformity of the stamped parts, and avoid cracking and other problems that may occur under long-term high-temperature heat dissipation environments, thus affecting service life.

[0034] Further, in step S2, the sputtering deposition step is as follows:

[0035] (1) Sputtering titanium oxide coating: the target material is Ti target, the sputtering gas is Ar, the reaction gas is O2, the sputtering power is 200-400W, and the pressure is 0.3-0.5Pa;

[0036] (2) Sputtering PTFE-silica coating: The target material is a silica target or a polytetrafluoroethylene target, and the sputtering gas is pure Ar; the sputtering power is 50-300W and the pressure is 0.3-0.5Pa.

[0037] Optionally, the titanium dioxide coating has a thickness of 100–200 nm; the PTFE-silica coating has a thickness of 150–300 nm.

[0038] Optionally, the sputtering power ratio of the silicon dioxide target to the polytetrafluoroethylene target is (3-5):1.

[0039] This application sputters a titanium oxide coating and a PTFE-silica coating onto an aluminum alloy surface. The titanium oxide coating serves as a transition layer and exhibits excellent adhesion to the aluminum alloy. The PTFE-silica coating also demonstrates strong adhesion to the titanium oxide coating. Therefore, the coatings are firmly bonded to the aluminum alloy and are not easily detached. By controlling the sputtering power ratio of the PTFE target and the silica target, the proportion of silica and polytetrafluoroethylene in the PTFE-silica coating is controlled. This allows for the formation of a uniform coating on the titanium oxide surface, which helps to rapidly release the heat absorbed by the heat spreader, reduces heat accumulation on the heat spreader surface, increases heat dissipation and uniformity, and also enhances the stability of the coating. It prevents cracking during long-term use and extends the service life.

[0040] On the other hand, an apparatus for micro-weaving on the surface of an IC heat sink is provided, comprising: a housing, wherein a stamping mechanism, a PVD sputtering mechanism and a transfer mechanism are provided inside the housing; the housing is provided with a door, which can be opened to place an aluminum alloy onto the stamping mechanism; a control panel is installed on the outer surface of the door, and an intelligent production system is provided in the control panel, which controls the intelligent production system to carry out production.

[0041] Optionally, the stamping mechanism includes a fixed platform, a lifting mechanism, a lower die, and an upper die;

[0042] The lifting mechanism and the lower mold are respectively mounted on a fixed platform, and the upper mold is mounted on the lifting mechanism, with the upper mold located directly above the lower mold.

[0043] The lower mold is configured as a groove structure, the size of the upper mold corresponds to the groove structure, and the upper surface of the lower mold is provided with a micro-woven structure;

[0044] The lifting mechanism includes a fixed frame and a hydraulic cylinder. The fixed frame is fixedly mounted on a fixed platform, and the hydraulic cylinder is mounted on the fixed frame. The movable end of the hydraulic cylinder is fixedly connected to the upper mold.

[0045] In use, the lifting mechanism drives the upper die to move downward. During the downward movement of the upper die, the upper die and the lower die cooperate to stamp and form the workpiece.

[0046] Optionally, the PVD sputtering mechanism includes a PVD chamber, a target material, and an electromagnet assembly. The target material is disposed at the top of the PVD chamber and is used to spray the workpiece to be coated. The electromagnet assembly is rotatably disposed in the PVD chamber and is used to suspend the workpiece to be coated in the chamber and can drive the workpiece to be coated to suspend and rotate.

[0047] The PVD chamber includes a shell and a door connecting the shell. The PVD chamber is opened through the door so that the workpiece to be coated can be placed in the PVD chamber through the opening. After the workpiece to be coated is placed, the opening is closed through the door to meet the conditions for the next step of vacuuming the coating chamber.

[0048] The PVD sputtering mechanism also includes an exhaust pipe connecting the inside and outside of the PVD chamber, and a vacuum pump connecting the exhaust pipe, for creating a near-vacuum environment within the PVD chamber.

[0049] Optionally, the transfer mechanism includes a base and a robotic arm mounted on the base. The end of the robotic arm is provided with a connecting seat, and a gripper mechanism is connected to the connecting seat. The gripper mechanism includes a driving component fixed to the bottom of the connecting seat. Two clamping plates are symmetrically provided at the bottom of the driving component. When it is necessary to grip an item through the gripper mechanism, the robotic arm drives the connecting seat and the gripper mechanism to move to the corresponding position, and the clamping plates are located on both sides of the item. The moving component moves the two clamping plates inward at the same time to fix the item, so that the item can be transferred to the corresponding position by the robotic arm and the gripper mechanism.

[0050] Compared with the prior art, this application has the following beneficial effects:

[0051] 1. This application first forms a microtexture on the surface of an aluminum alloy using micro-nano technology, then stamps it, and finally sputters a titanium oxide coating and a PTFE-silica composite coating on the surface to prepare an IC heat sink. The IC heat sink has good thermal conductivity, which can accelerate heat transfer and enhance heat dissipation. Moreover, the sputtered functional coating has high adhesion to the aluminum alloy workpiece, good stability, and a small difference in thermal expansion coefficient with the chip, thus meeting the heat dissipation requirements of high heat flux density chips.

[0052] 2. This application uses an aluminum alloy containing Si, Cu, Ti, B, Sc, and Sr to produce IC heat sinks. By adjusting the proportions of each element in the aluminum alloy, the resulting aluminum alloy achieves a thermal conductivity of 200 W / (m·K), which is higher than that of conventional aluminum alloys, resulting in superior heat dissipation performance. Furthermore, it forms a stable bond with titanium dioxide and PTFE-silica composite coatings, improving stability. In addition, this aluminum alloy has good machinability, avoiding defects during subsequent stamping processes, thereby improving the quality of the IC heat sink. During the aluminum alloy stamping process, pre-pressurization at a low temperature followed by high-temperature stamping, combined with the use of stamping oil, reduces damage during stamping, improves the surface quality of the stamped parts, and thus enhances the heat dissipation performance of the IC heat sink.

[0053] 3. The IC heat sink of this application has a titanium oxide coating and a PTFE-silica composite coating sputtered on the surface of an aluminum alloy. The titanium oxide coating serves as a transition layer and has good adhesion to the aluminum alloy. The PTFE-silica coating also has good adhesion to the titanium oxide coating, resulting in strong bonding between the titanium oxide coating, the PTFE-silica composite coating and the aluminum alloy, and making them less prone to peeling off. By controlling the sputtering power of the two targets, the ratio of silica and polytetrafluoroethylene in the PTFE-silica coating can be controlled, which can increase the adhesion of the coating and help to quickly release the heat absorbed by the heat sink, increase heat dissipation, improve heat dissipation uniformity, and make the resulting IC heat sink surface have a small temperature difference, reducing damage to the chip caused by uneven dispersion. On the other hand, its hydrophobicity reduces the adhesion of contaminants, ensures long-term heat dissipation stability, and can also reduce problems such as coating cracking during thermal expansion and contraction. Attached Figure Description

[0054] Figure 1 This is an external structural diagram of the device for forming a micro-woven structure on the surface of an IC heat sink;

[0055] Figure 2 This is a diagram of the internal structure of the device for forming the micro-woven surface of an IC heat sink;

[0056] Figure 3 This is a diagram of the external structure of the PVD sputtering mechanism.

[0057] Explanation of reference numerals in the attached diagrams: Box body-1, Box door-2, Control panel-3;

[0058] Stamping forming mechanism-100, fixed platform-101, lifting mechanism-102, lower die-103, upper die-104, fixed frame-1021, hydraulic cylinder-1022;

[0059] PVD sputtering mechanism-200, PVD chamber-201, target material-202, electromagnet assembly-203, exhaust pipe-204, vacuum pump-205, housing 2011, door 2012;

[0060] Transfer mechanism-300, base-301, robotic arm-302, connecting seat-303, drive component-304, clamping plate-305. Detailed Implementation

[0061] To more clearly illustrate the overall concept of this application, a detailed explanation is provided below with reference to the accompanying drawings.

[0062] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0063] Furthermore, it should be understood in the description of this application that the terms "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0064] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0065] In this application, unless otherwise expressly specified and limited, the "above" or "below" of the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0066] like Figure 1-3 As shown, it includes: a housing 1, inside which are installed a stamping forming mechanism 100, a PVD sputtering mechanism 200 and a transfer mechanism 300; a door 2 is provided on the housing 1, which can be opened to place aluminum alloy workpieces on the stamping forming mechanism 100; a control panel 3 is installed on the outer surface of the door 2, and an intelligent production system is provided in the control panel 3, which controls the intelligent production system to carry out production.

[0067] Optionally, the stamping forming mechanism 100 includes a fixed platform 101, a lifting mechanism 102, a lower die 103, and an upper die 104; the lifting mechanism 102 and the lower die 103 are respectively disposed on the fixed platform 101, the upper die 104 is disposed on the lifting mechanism 102, and the upper die 104 is located directly above the lower die 103.

[0068] The lower mold 103 is configured with a groove structure, and the upper mold 104 has dimensions corresponding to the groove structure. The upper surface of the lower mold 103 is provided with a micro-textured structure for processing workpieces with micro-textured surfaces.

[0069] The lifting mechanism 102 includes a fixed frame 1021 and a hydraulic cylinder 1022. The fixed frame 1021 is fixedly mounted on the fixed platform 101, and the hydraulic cylinder 1022 is mounted on the fixed frame 1021. The movable end of the hydraulic cylinder 1022 is fixedly connected to the upper mold 104.

[0070] In use, the lifting mechanism 102 drives the upper die 104 to move downward. During the downward movement of the upper die 104, the upper die 104 and the lower die 103 cooperate to achieve stamping and forming of the workpiece.

[0071] Optionally, the PVD sputtering mechanism 200 includes a PVD chamber 201, a target material 202, and an electromagnet assembly 203. The target material 202 is located at the top of the PVD chamber 201 and is used to spray the workpiece to be coated. The electromagnet assembly 203 is rotatably located inside the PVD chamber 201 and is used to suspend the workpiece to be coated inside the chamber and can drive the workpiece to be coated to rotate. The target material 202 can be a single target or a double target.

[0072] The PVD sputtering mechanism 200 also includes a housing 2011 and a door 2012 connected to the housing 2011. The PVD chamber 201 is opened through the door 2012 to place the workpiece to be coated into the PVD chamber 201. After the workpiece to be coated is placed, the opening is closed through the door to meet the conditions for the next step of vacuuming the coating chamber.

[0073] The PVD sputtering mechanism 200 also includes an exhaust pipe 204 connecting the inside and outside of the PVD chamber 201, and a vacuum pump 205 connecting the exhaust pipe 204, for achieving a near-vacuum environment inside the PVD chamber 201.

[0074] Optionally, the transfer mechanism 300 includes a base 301 and a robotic arm 302 disposed on the base. The end of the robotic arm 302 is provided with a connecting seat 303, and a gripper mechanism is connected through the connecting seat 303. The gripper mechanism includes a driving member 304 fixed to the bottom of the connecting seat 303, and two clamping plates 305 are symmetrically provided at the bottom of the driving member 304.

[0075] When gripping a workpiece, the robotic arm 302 drives the connecting seat 303 and the gripper mechanism to move to the corresponding position, and the clamping plate 305 is positioned on both sides of the workpiece. The driving component 304 causes the two clamping plates 305 to move inward simultaneously to fix the item, so that the robotic arm 302 and the gripper mechanism can transfer the item to the corresponding position.

[0076] The present application will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of this application are obtained through conventional commercial means.

[0077] Example 1

[0078] A method for fabricating microtextures on the surface of an IC heat sink includes the following steps:

[0079] S1. The aluminum alloy is placed into a stamping die for stamping to obtain a workpiece with a micro-textured surface. The stamping steps are as follows: the aluminum alloy is heated to 480℃ and held for 2 hours, then cooled to 50℃; the die is preheated to 45℃, and stamping oil is applied to the die surface and the aluminum alloy surface; the workpiece is placed into the die for pre-stamping under the following conditions: temperature 75℃, drawing rate 0.15mm / s, blank holder force 2N / mm. 2 After pre-stamping, cool to 50℃; then perform re-stamping under the following conditions: temperature 250℃, drawing rate 0.4mm / s, blank holder force 4N / mm. 2 After stamping, cool to room temperature and clean to remove surface stamping oil; the stamping oil contains the following components by weight percentage: diisooctyl adipate 80%, isoparaffin solvent oil 5%, 1,3,5-cyclohexanetriethanol 5%, stearoyl benzoyl 3%, fatty alcohol polyoxyethylene ether (carbon chain 9, EO number 3) 5%, graphite emulsion 2%;

[0080] S2. Transfer the workpiece to the PVD chamber, evacuate, introduce inert gas, turn on the sputtering power supply, and sputter-deposit a Ti / PTFE-silica composite coating on the side with microtexture, as follows:

[0081] Sputtered titanium oxide coating: The target material is Ti target, the sputtering gas is Ar, the reactive gas is O2, the sputtering power is 200W, the pressure is 0.3Pa, and the thickness is 100nm;

[0082] Sputtering PTFE-silica coating: The target materials are silica target and polytetrafluoroethylene target. The sputtering power of the silica target is 250W and the sputtering power of the polytetrafluoroethylene target is 50W; the pressure is 0.3Pa and the thickness is 300nm.

[0083] S3. Turn off the sputtering power supply, unload the material, and you will get the product.

[0084] The aluminum alloy is prepared by the following method:

[0085] (1) The aluminum alloy contains, by weight percentage: Si 2%, Cu 0.4%, Ti 0.1%, B 0.5%, Sc 0.02%, Sr 0.03%, unavoidable impurities <0.1%, and the balance is aluminum;

[0086] (2) According to the formula, pure aluminum is first added to the melting furnace and smelted at 680°C. After the melting is completed, the temperature is raised to 720°C, the remaining components are added, and the melting is continued to obtain the alloy liquid. Sodium-free refining agent is added (the amount of sodium-free refining agent is 0.2% of the total weight of the metal in the furnace), and it is refined at 710°C for 30 minutes. The temperature of the alloy liquid is controlled at 680°C, and it is poured into the die casting machine for die casting to obtain the aluminum alloy.

[0087] Example 2

[0088] A method for fabricating microtextures on the surface of an IC heat sink includes the following steps:

[0089] S1. The aluminum alloy is placed into a stamping die for stamping to obtain a workpiece with a micro-textured surface. The stamping steps are as follows: the aluminum alloy is heated to 500℃ and held for 2 hours, then cooled to 55℃; the die is preheated to 50℃, and then stamping oil is applied to the die surface and the aluminum alloy surface; the workpiece is placed into the die for pre-stamping under the following conditions: temperature 85℃, drawing rate 0.3mm / s, blank holder force 3N / mm. 2 After pre-stamping, cool to 55℃; then perform re-stamping under the following conditions: temperature 270℃, drawing rate 0.5mm / s, blank holder force 5N / mm. 2 After stamping, cool to room temperature and clean to remove surface stamping oil. The stamping oil contains the following components by weight percentage: 90% diisooctyl adipate, 3% isoparaffin solvent oil, 3% 1,3,5-cyclohexanetriethanol, 1% stearoyl benzoyl, 2.5% fatty alcohol polyoxyethylene ether (carbon chain 12, EO number 4), and 0.5% graphite emulsion.

[0090] S2. Transfer the workpiece to the PVD chamber, evacuate, introduce inert gas, turn on the sputtering power supply, and sputter-deposit a Ti / PTFE-silica composite coating on the side with microtexture, as follows:

[0091] Sputtered titanium oxide coating: The target material is Ti target, the sputtering gas is Ar, the reactive gas is O2, the sputtering power is 400W, the pressure is 0.5Pa, and the thickness is 200nm;

[0092] Sputtering PTFE-silica coating: The target materials are silica target and polytetrafluoroethylene target. The sputtering power of the silica target is 300W and the sputtering power of the polytetrafluoroethylene target is 100W. The pressure is 0.5Pa and the thickness is 150nm.

[0093] S3. Turn off the sputtering power supply, unload the material, and you will get the product.

[0094] The aluminum alloy is prepared by the following method:

[0095] (1) The aluminum alloy contains, by weight percentage: Si 3%, Cu 0.2%, Ti 0.05%, B 0.1%, Sc 0.08%, Sr 0.05%, unavoidable impurities <0.1%, and the balance is aluminum;

[0096] (2) According to the formula, pure aluminum is first added to the melting furnace and smelted at 680°C. After the melting is completed, the temperature is raised to 720°C, the remaining components are added, and the melting is continued to obtain the alloy liquid. Sodium-free refining agent is added (the amount of sodium-free refining agent is 0.2% of the total weight of the metal in the furnace), and it is refined at 710°C for 30 minutes. The temperature of the alloy liquid is controlled at 680°C, and it is poured into the die casting machine for die casting to obtain the aluminum alloy.

[0097] Example 3

[0098] The difference from Example 1 is that the aluminum alloy, by weight percentage, contains: 2% Si, 0.4% Cu, 0.1% Ti, 0.5% B, 0.06% Sc, 0.05% Sr, unavoidable impurities <0.1%, and the balance is aluminum; that is, the difference from Example 1 is that the weight ratio of (Sr+Sc) to Si in the aluminum alloy is 0.055.

[0099] Example 4

[0100] The difference from Example 2 is that the stamping oil in the stamping process contains the following components by weight percentage: 90 parts diisooctyl adipate, 3 parts isoalkane solvent oil, 8 parts 1,3,5-cyclohexanetriethanol, 5 parts stearoyl benzoyl, 2.5 parts fatty alcohol polyoxyethylene ether, and 0.5 parts graphite emulsion.

[0101] Example 5

[0102] The difference from Example 2 is that 1,3,5-cyclohexanetriethanol was not added to the stamping oil.

[0103] Example 6

[0104] The difference from Example 2 is that stearoyl benzoyl was not added to the stamping oil.

[0105] Example 7

[0106] The difference from Example 2 is that there is no pre-stamping step in the stamping process.

[0107] Example 8

[0108] The difference from Example 2 is that in the sputtering of the PTFE-silica coating, the sputtering power of the silica target is 300W and the sputtering power of the polytetrafluoroethylene target is 50W, that is, the sputtering power ratio of the silica target to the polytetrafluoroethylene target is 6:1.

[0109] Example 9

[0110] The difference from Example 2 is that in the PTFE-silica coating, the sputtering power of the silica target is 100W and the sputtering power of the polytetrafluoroethylene target is 100W, that is, the sputtering power ratio of the silica target to the polytetrafluoroethylene target is 1:1.

[0111] Comparative Example 1

[0112] The difference from Example 2 is that the aluminum alloy, by weight percentage, contains: Si 5%, Cu 0.05%, Ti 0.15%, B 0.8%, Sc 0.1%, Sr 0.08%, unavoidable impurities <0.1%, and the balance is aluminum; the preparation method of the aluminum alloy remains unchanged.

[0113] Comparative Example 2

[0114] The difference from Example 2 is that Sc was not added to the aluminum alloy, while the contents of the other components remained unchanged; the preparation method of the aluminum alloy remained unchanged.

[0115] Comparative Example 3

[0116] The difference from Example 2 is that Sr was not added to the aluminum alloy, while the contents of the other components remained unchanged; the preparation method of the aluminum alloy remained unchanged.

[0117] Test Example 1

[0118] The thermal conductivity, compressive strength, and elongation after fracture of the aluminum alloys prepared in the above embodiments and comparative examples were tested. Thermal conductivity was tested using the flash test method (GB / T22588-2008), and compressive strength and elongation after fracture were tested according to GB / T228.1-2021.

[0119] The test results are shown in Table 1 below. It can be seen that the aluminum alloy provided in this application has high yield strength and elongation, good stamping performance, high thermal conductivity, and high heat transfer efficiency, which can be used for the heat dissipation requirements of high heat flux density chips.

[0120] Table 1. Properties of Aluminum Alloys

[0121]

[0122] Test Example 2

[0123] Test the heat dissipation performance of IC heat sink

[0124] The IC heat sinks and stainless steel substrates of the same size from the above embodiments and comparative examples were used as samples and placed on a heating plate. The temperature of the heating plate was controlled at 100°C and equilibrated for 30 minutes. The surface temperatures of the stainless steel substrate and the IC heat sink were tested. During the test, five points were selected for temperature measurement of each sample, and the average value and standard deviation were calculated to evaluate its heat dissipation performance.

[0125] The results are shown in Table 2. It can be seen that, compared to stainless steel, the IC heat sinks prepared in the embodiments of this application have good heat dissipation performance and good heat dissipation uniformity, especially the IC heat sinks prepared in Examples 2 and 3, which have the best heat dissipation performance. It can also be seen that the heat dissipation performance of Comparative Examples 1-3 is significantly different from that of Example 2, indicating that the scientific ratio of elements in the aluminum alloy helps to improve the heat dissipation performance of the heat sink. The heat dissipation performance of Example 1 is also lower than that of Examples 2 and 3, which shows that when the ratio of Sc, Sr, and Si in the aluminum alloy is within a certain range, the aluminum alloy can obtain the optimal thermal conductivity, thereby giving the heat sink better heat dissipation performance.

[0126] Table 2. Results of heat dissipation performance test

[0127]

[0128] Test Example 3

[0129] The contact angle and coating adhesion of the IC heat sink surface were tested. The contact angle was tested using a contact angle measuring instrument, and the adhesion was tested using the cross-cut test method in GB / T 9286-2021 to determine the coating peeling rate.

[0130] The test results are shown in Table 3 below.

[0131] Table 3. Coating adhesion test results

[0132]

[0133] Tests showed that the contact angles of the IC heat sinks provided in this application were all above 120°, indicating good surface hydrophobicity. As shown in the table, the coating peeling rate of the IC heat sinks obtained in Examples 1-3 was <5%, indicating good adhesion and stability between the coating and the aluminum alloy.

[0134] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, this application is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope of this application should be within the protection scope of this application.

Claims

1. A method for fabricating microtextured structures on the surface of an IC heat sink, characterized in that, Includes the following steps: S1. The aluminum alloy is placed into a stamping die for stamping to obtain a workpiece with a micro-texture on one side; S2. Transfer the workpiece to the PVD chamber, evacuate, introduce inert gas, turn on the sputtering power supply, and sequentially sputter and deposit a titanium oxide coating and a PTFE-silica coating on the side with microtexture. S3. Turn off the sputtering power supply, unload the material, and you will get the product. The aluminum alloy, by weight percentage, contains: Si 2%–3%, Cu 0.2%–0.4%, Ti 0.05%–0.1%, B 0.1%–0.5%, Sc 0.03%–0.08%, Sr 0.02%–0.05%, unavoidable impurities <0.1%, and the balance is aluminum; the weight ratio of the total weight of Sr and Sc to the weight of Si satisfies: 0.04 < (Sr + Sc) / Si < 0.06; The stamping process is as follows: (1) Heat the aluminum alloy to 480-500℃, hold for 0.5-2 hours, and then cool to 50-55℃; (2) Preheat the mold to 45-50°C, and then coat the mold surface and the aluminum alloy surface with stamping oil; (3) The aluminum alloy is placed into the mold for pre-stamping. The pre-stamping conditions are: temperature 75-85℃, drawing speed 0.15-0.3mm / s, blank holder force 2-3N / mm. 2 After pre-stamping, cool to 50-55℃; (4) Perform re-stamping. The re-stamping conditions are: temperature 250-270℃, drawing speed 0.4-0.5mm / s, blank holder force 4-5N / mm. 2 ; (5) After the stamping is completed, cool to room temperature and clean to remove the stamping oil from the surface; The stamping oil used in the stamping process contains the following components by weight: 80-90 parts base oil, 3-5 parts isoparaffin solvent oil, 3-5 parts 1,3,5-cyclohexanetriethanol, 1-3 parts stearoylbenzoyl, 2-5 parts fatty alcohol polyoxyethylene ether, and 0.5-2 parts graphite emulsion.

2. The method for fabricating a microwoven surface on an IC heat sink according to claim 1, characterized in that, The aluminum alloy is prepared by the following method: (1) According to the formula, add pure aluminum into the melting furnace first, and melt at 680-700℃; (2) Heat to 720-740℃, add the remaining components, and continue smelting to obtain an alloy liquid; (3) Refine with refining agent; (4) The temperature of the alloy liquid is controlled at 680-700℃ and poured into the die casting machine for die casting to obtain aluminum alloy.

3. The method for forming a microwoven surface on an IC heat sink according to claim 1, characterized in that, The sputtering deposition step is as follows: (1) Sputtering titanium oxide coating: the target material is Ti target, the sputtering gas is Ar, the reaction gas is O2, the sputtering power is 200-400W, and the pressure is 0.3-0.5Pa; (2) Sputtering PTFE-silica coating: The target material is a silica target or a polytetrafluoroethylene target, and the sputtering gas is pure Ar; the sputtering power is 50-300W and the pressure is 0.3-0.5Pa.

4. The method for forming a microwoven surface on an IC heat sink according to claim 3, characterized in that, The thickness of the titanium dioxide coating is 100–200 nm; the thickness of the PTFE-silica coating is 150–300 nm.

5. The method for forming a microwoven surface on an IC heat sink according to claim 3, characterized in that, The sputtering power ratio of the silica target to the polytetrafluoroethylene target is (3-5):1.

Images