Silicon carbide heat sink structure
By electroplating a copper layer on a silicon carbide substrate to form a copper-silicon carbide-copper structure, the bottleneck of the existing DBC copper clad process in heat dissipation is solved, high thermal conductivity and high reliability are achieved, and it is suitable for the needs of new semiconductor materials.
Patent Information
- Application Number
- CN202421738903.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Priority Date
- 2024-02-01
- Filing Date
- 2024-07-22
- Publication Date
- 2025-04-25
- Estimated Expiration
- 2034-07-22
AI Technical Summary
The existing DBC copper clad process has thermal conductivity and reliability bottlenecks in terms of heat dissipation, which cannot meet the high thermal conductivity and high reliability requirements of new semiconductor materials.
A silicon carbide substrate is used as a heat sink structure, and a copper-silicon carbide-copper structure is formed by electroplating a copper layer on both sides of it, combining the seed layer and the film process to improve thermal conductivity and reliability.
It achieves high thermal conductivity and high reliability, avoids damage to the material by high temperature, and is suitable for the heat dissipation needs of new semiconductor materials.
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Figure CN222802329U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of heat dissipation of laser chips, and in particular to a silicon carbide heat sink structure and a processing technology thereof. Background Art
[0002] At present, most of the heat dissipation modules of power devices such as IGBT modules, high-power LEDs, and semiconductor laser pump sources in my country's new energy vehicle motor drive inverters use alumina or aluminum nitride DBC (Direct Bonding Copper) copper-clad heat sink heat dissipation solutions. Since the DBC process requires high temperature to sinter the copper foil on the surface of the substrate, and then wet-etch the required circuit pattern. In this process, the high temperature during sintering will reduce the performance of the material. When wet-etching thick copper, the etching solution will excessively corrode the bottom of the copper layer during a long etching process, and the non-vertical copper side will have an adverse effect on heat dissipation. Therefore, the bottlenecks in thermal conductivity and reliability of this method make this heat dissipation solution no longer suitable for new semiconductor materials.
[0003] With the accelerated development and introduction of third-generation semiconductor materials silicon carbide (SiC) and gallium nitride (GaN) chip technology, high power density and miniaturization have prompted the power module's requirements for heat dissipation materials to develop in the direction of high thermal conductivity and high reliability. The existing DBC copper cladding process can no longer meet the heat dissipation requirements, and a new heat sink structure is urgently needed to meet the needs. Utility Model Content
[0004] The present application provides a silicon carbide heat sink structure and a processing technology thereof to solve the technical problem that the existing DBC copper coating process in the background technology cannot meet the heat dissipation requirements.
[0005] In order to solve the above technical problems, a technical solution adopted in the present application is to provide a silicon carbide heat sink structure and a processing technology thereof, wherein the silicon carbide heat sink structure comprises:
[0006] A silicon carbide substrate, a first electroplated copper layer, and a second electroplated copper layer, wherein the first electroplated copper layer is disposed on the reverse side of the silicon carbide substrate, and the second electroplated copper layer is disposed on the front side of the silicon carbide substrate, the thickness of the silicon carbide substrate is greater than the thickness of the first electroplated copper layer and the second electroplated copper layer, the width of the silicon carbide substrate is greater than the width of the first electroplated copper layer and the second electroplated copper layer, the thickness of the first electroplated copper layer is the same as the thickness of the second electroplated copper layer, and the width of the first electroplated copper layer is smaller than the width of the second electroplated copper layer.
[0007] By adopting the above technical solution, the copper layer is electroplated on the surfaces of both sides of the ceramic substrate to form a copper-silicon carbide-copper structure. The ceramic substrate adopts a silicon carbide substrate. Silicon carbide is a third-generation semiconductor material with high temperature resistance, corrosion resistance, high stability and high thermal conductivity. The thermal conductivity of silicon carbide is greater than 390W / mk, which is very close to the thermal conductivity of copper (about 397W / mk), and has a good thermal conductivity effect. The width of the first electroplated copper layer is smaller than that of the second electroplated copper layer. The chip is placed on the edge of the second electroplated copper layer without affecting the scattering of its light, thereby ensuring the power of the chip.
[0008] Optionally, the silicon carbide heat sink structure includes a seed layer, which is disposed on the front and back surfaces of the silicon carbide substrate, and the seed layer is respectively disposed between the first electroplated copper layer, the second electroplated copper layer and the silicon carbide substrate.
[0009] By adopting the above technical solution, the seed layers are arranged on both sides of the silicon carbide substrate, so that the first electroplated copper layer and the second electroplated copper layer can be electroplated onto the silicon carbide substrate, playing a role of load-bearing transition.
[0010] Optionally, the seed layer is a titanium-copper or titanium-tungsten alloy-copper metallization layer structure.
[0011] By adopting the above technical solution, the titanium copper or titanium tungsten alloy copper metallization layer is attached to the front and back sides of the silicon carbide substrate, combined with the first electroplated copper layer and the second electroplated copper layer, which facilitates copper plating on the silicon carbide substrate. The titanium tungsten alloy metal mixture has high strength, corrosion resistance and high temperature stability, making the overall structure relatively stable.
[0012] Optionally, the thickness of the silicon carbide substrate is 0.3-0.6 mm, and the thickness of the first electroplated copper layer and the second electroplated copper layer is 0.002-0.09 mm.
[0013] By adopting the above technical solution, the structure of copper-silicon carbide-copper is relatively stable, and its thermal conductivity and corrosion resistance are better.
[0014] Optionally, the thickness of the first electroplated copper layer and the second electroplated copper layer is 0.002-0.09 mm.
[0015] By adopting the above technical solution, the overall structure is relatively stable and the thermal conductivity is better, which is convenient for chip heat dissipation.
[0016] Optionally, a circuit layer is provided on the second electroplated copper layer.
[0017] By adopting the above technical solution, the circuit layer connects the second electroplated copper layer and the chip, so that the chip is electrically connected to the electroplated copper layer.
[0018] The processing technology of silicon carbide heat sink structure includes the following steps:
[0019] Putting the silicon carbide substrate into a magnetron sputtering table, turning on the magnetron sputtering table, and sputtering a layer of metal titanium or titanium-tungsten alloy on one side of the silicon carbide substrate and then sputtering a layer of metal copper as a seed layer. After the sputtering is completed, turning the silicon carbide substrate over, and sputtering a layer of metal titanium or titanium-tungsten alloy on the other side of the silicon carbide substrate and then sputtering a layer of metal copper by the magnetron sputtering table;
[0020] Putting the silicon carbide substrate with the metal layer of titanium copper or titanium tungsten alloy copper sputtered on it into a photolithography machine, turning on the photolithography machine, and performing local exposure processing on the silicon carbide substrate by the photolithography machine, and forming a specified pattern on the surface of the silicon carbide substrate through light shielding and development;
[0021] The silicon carbide substrate is placed in an electrolytic bath filled with electrolyte, and both sides of the silicon carbide substrate are plated with metal copper in the electrolytic bath.
[0022] By adopting the above technical solution, the influence of high temperature on materials and circuit structures is avoided. The thin film and photolithography development technology is used to make the circuit structure on the substrate more refined, with excellent solderability and wire bonding assembly characteristics, which is suitable for precision electronic packaging. The use of electroplated copper will not cause excessive corrosion to the copper layer and is more conducive to heat dissipation.
[0023] Optionally, before placing the silicon carbide substrate into a magnetron sputtering table, turning on the magnetron sputtering table, and sputtering a layer of metal titanium or titanium-tungsten alloy on one side of the silicon carbide substrate and then sputtering a layer of metal copper as a seed layer, and after the sputtering is completed, turning the silicon carbide substrate over, and before the step of sputtering a layer of metal titanium or titanium-tungsten alloy on the other side of the silicon carbide substrate and then sputtering a layer of metal copper, the magnetron sputtering table is turned on and the equipment inspection of the magnetron sputtering table is performed to ensure that the magnetron sputtering table can operate normally.
[0024] By adopting the above technical solution, the magnetron sputtering table is inspected before operation to improve process safety and efficiency, and to prevent malfunctions during operation that affect processing efficiency.
[0025] Optionally, before placing the silicon carbide substrate in a magnetron sputtering table, turning on the magnetron sputtering table, and sputtering a layer of metal titanium or titanium-tungsten alloy on one side of the silicon carbide substrate and then sputtering a layer of metal copper as a seed layer, the silicon carbide substrate is flipped over after the sputtering is completed, and before the magnetron sputtering table sputters a layer of metal titanium or titanium-tungsten alloy on the other side of the silicon carbide substrate and then sputters a layer of metal copper, the surface of the silicon carbide substrate is cleaned to ensure that the surface of the silicon carbide substrate is free of impurities.
[0026] By adopting the above technical solution, impurities can be prevented from being mixed in during magnetron sputtering, which would affect product quality, resulting in the thermal conductivity being affected, and further affecting the heat dissipation efficiency.
[0027] Optionally, after the step of placing the silicon carbide substrate in an electrolytic bath filled with electrolyte and plating metallic copper on both sides of the silicon carbide substrate in the electrolytic bath, the metallic copper on the silicon carbide substrate is ground and polished.
[0028] By adopting the above technical solution, the surfaces of the first electroplated copper layer and the second electroplated copper layer are polished to achieve the required surface quality, so that the surface roughness Ra reaches less than 0.05 microns.
[0029] The beneficial effects of the present application are as follows: the present application provides a silicon carbide heat sink structure and a processing technology thereof; the copper-silicon carbide-copper structure in the silicon carbide heat sink structure has a good thermal conductivity; the width of the first electroplated copper layer is smaller than the width of the second electroplated copper layer; the chip is made at the edge of the second electroplated copper layer without affecting the scattering of its light, thereby ensuring the power of the chip; the structure is simple, will not cause excessive corrosion to the copper layer, and is more conducive to heat dissipation. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:
[0031] Figure 1 is a schematic diagram of the structure of a silicon carbide heat sink provided in an embodiment of the present application;
[0032] Figure 2 It is a processing flow chart of the silicon carbide heat sink structure provided in the embodiment of the present application.
[0033] Description of reference numerals:
[0034] 10. Silicon carbide substrate; 20. First electroplated copper layer; 30. Second electroplated copper layer; 40. Circuit layer. DETAILED DESCRIPTION
[0035] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0036] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement, etc. between the components under a certain specified posture (as shown in the accompanying drawings). If the specified posture changes, the directional indication will also change accordingly.
[0037] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.
[0038] In this embodiment, the silicon carbide heat sink structure adopts the direct copper plating substrate technology DPC (Direct Plating Copper) to electroplate the copper layer on the surface of both sides of the ceramic substrate to form a copper-silicon carbide-copper structure. The ceramic substrate adopts a silicon carbide substrate 10. Silicon carbide is a third-generation semiconductor material with high temperature resistance, corrosion resistance, high stability and high thermal conductivity. Its thermal conductivity is greater than 390W / mk, which is very close to the thermal conductivity of copper (about 397W / mk), and more than twice that of aluminum nitride. The resistivity of insulating silicon carbide is greater than 1*107Ω*cm, and it has excellent insulation. The direct copper plating substrate technology DPC mainly uses surface deposition processes such as evaporation and magnetron sputtering to metallize the substrate surface. After cleaning the surface of the silicon carbide substrate 10, place it in a magnetron sputtering table, sputter a layer of metal titanium or titanium-tungsten alloy on the surface of the silicon carbide substrate 10, and then sputter a layer of metal copper as a seed layer, then complete the pattern production through thin film process photolithography and development, and finally electroplate copper metal to the required thickness and grind and polish the surface to achieve the required surface quality. The DPC process completely avoids the impact of high temperature on materials and circuit structures, and uses thin film and photolithography development technology to make the circuit structure on the substrate more refined. The surface roughness can be Ra0.05 microns, with excellent solderability and wire bonding assembly characteristics, suitable for precision electronic packaging. The DPC process uses electroplated copper, which will not cause excessive corrosion to the copper layer and is more conducive to heat dissipation.
[0039] like Figure 1As shown, the present application provides a silicon carbide heat sink structure and a processing technology thereof, wherein the silicon carbide heat sink structure comprises a silicon carbide substrate 10, a first electroplated copper layer 20, and a second electroplated copper layer 30, wherein the first electroplated copper layer 20 is disposed on the reverse side of the silicon carbide substrate 10, and the second electroplated copper layer 30 is disposed on the front side of the silicon carbide substrate 10, the thickness of the silicon carbide substrate 10 is greater than the thickness of the first electroplated copper layer 20 and the second electroplated copper layer 30, the width of the silicon carbide substrate 10 is greater than the width of the first electroplated copper layer 20 and the second electroplated copper layer 30, the thickness of the first electroplated copper layer 20 is the same as the thickness of the second electroplated copper layer 30, and the width of the first electroplated copper layer 20 is smaller than the width of the second electroplated copper layer 30.
[0040] The copper layer is electroplated on the surfaces of both sides of the ceramic substrate to form a copper-silicon carbide-copper structure. The ceramic substrate adopts a silicon carbide substrate 10. Silicon carbide is a third-generation semiconductor material with high temperature resistance, corrosion resistance, high stability and high thermal conductivity. The thermal conductivity of silicon carbide is greater than 390W / mk, which is very close to the thermal conductivity of copper (about 397W / mk), and has a good thermal conductivity effect. The width of the first electroplated copper layer 20 is smaller than that of the second electroplated copper layer 30. The chip is placed on the edge of the second electroplated copper layer 30 without affecting the scattering of its light, thereby ensuring the power of the chip.
[0041] In this embodiment, the silicon carbide heat sink structure includes a seed layer, which is arranged on the front and back sides of the silicon carbide substrate 10. The seed layers are respectively arranged between the first electroplated copper layer 20, the second electroplated copper layer 30 and the silicon carbide substrate 10. The seed layers are arranged on both sides of the silicon carbide substrate 10 so that the first electroplated copper layer 20 and the second electroplated copper layer 30 can be electroplated onto the silicon carbide substrate 10, playing a role of load-bearing transition. The seed layer is a titanium-copper or titanium-tungsten alloy copper metallization layer, which is attached to the front and back sides of the silicon carbide substrate 10 and combined with the first electroplated copper layer 20 and the second electroplated copper layer 30 to facilitate copper plating on the silicon carbide substrate 10. Titanium or titanium-tungsten has high strength, corrosion resistance and high temperature stability, making the overall structure relatively stable.
[0042] The thickness of the silicon carbide substrate 10 is 0.3-0.6 mm, the thickness of the first electroplated copper layer 20 and the second electroplated copper layer 30 is 0.005~0.09 mm, the copper-silicon carbide-copper structure is relatively stable, and its thermal conductivity is good and its corrosion resistance is good. In this embodiment, the thickness of the first electroplated copper layer 20 and the second electroplated copper layer 30 is 0.005~0.09 mm, and its overall structure is relatively stable and has good thermal conductivity, which is convenient for chip heat dissipation. A circuit layer 40 is provided on the second electroplated copper layer 30, and the circuit layer 40 connects the second electroplated copper layer 30 and the chip, so that the chip is electrically connected to the electroplated copper layer.
[0043] like Figure 2As shown, the present application provides a processing technology for a silicon carbide heat sink structure, and the processing technology for a silicon carbide heat sink structure includes the following steps:
[0044] S1: placing the silicon carbide substrate 10 into a magnetron sputtering table, turning on the magnetron sputtering table, and sputtering a layer of metal titanium or titanium-tungsten alloy on one side of the silicon carbide substrate 10 and then sputtering a layer of metal copper as a seed layer. After the sputtering is completed, the silicon carbide substrate 10 is turned over, and the magnetron sputtering table sputters a layer of metal titanium or titanium-tungsten alloy on the other side of the silicon carbide substrate 10 and then sputters a layer of metal copper.
[0045] S2: Place the silicon carbide substrate 10 sputtered with the metal titanium tungsten alloy into a photolithography machine, turn on the photolithography machine, and perform local exposure processing on the silicon carbide substrate 10 by the photolithography machine. Through light shielding and development, a specified pattern is formed on the surface of the silicon carbide substrate 10.
[0046] S3: placing the silicon carbide substrate 10 into an electrolytic bath filled with electrolyte, and both sides of the silicon carbide substrate 10 are plated with metallic copper in the electrolytic bath.
[0047] The direct copper plating substrate technology DPC (Direct Plating Copper) is used to avoid the impact of high temperature on materials and circuit structures. The thin film and photolithography development technology is used to make the circuit structure on the substrate more refined. It has excellent solderability and wire bonding assembly characteristics, which is suitable for precision electronic packaging. The use of electroplated copper will not cause excessive corrosion to the copper layer and is more conducive to heat dissipation.
[0048] Tungsten steel is an alloy material that uses tungsten to replace part of the carbon element in steel. It has the advantages of high hardness, high toughness, wear resistance, and corrosion resistance. It is widely used in cutting, mining tools, and other fields. Titanium alloy is composed of titanium, aluminum, vanadium and other elements. It has the characteristics of low density, high strength, corrosion resistance, and good high temperature stability. It can be used in aerospace, automotive, medical and other fields.
[0049] The fusion of tungsten steel and titanium alloy can bring out the respective advantages of both to form a new material with the following advantages: High strength: Tungsten steel and titanium alloy have high strength respectively. After fusion, the strength of the new material is higher and it can be used in heavy-duty tools, aerospace, etc. Corrosion resistance: Tungsten steel is more difficult to react with chemical substances, while titanium alloy has good corrosion resistance. After fusion, the new material has stronger corrosion resistance and can be used in chemical industry, marine equipment and other fields. High temperature stability: Both tungsten steel and titanium alloy have high temperature stability. After fusion, the new material can be used for the manufacture of parts in high temperature environment. Lightweight: Due to the low density of titanium alloy, the new material after fusion is lightweight and can be used in aerospace, automobile and other fields.
[0050] The silicon carbide substrate 10 is placed in a magnetron sputtering table, the magnetron sputtering table is turned on, and the magnetron sputtering table sputters a layer of metal titanium or titanium-tungsten alloy on one side of the silicon carbide substrate 10 and then sputters a layer of metal copper as a seed layer. After the sputtering is completed, the silicon carbide substrate 10 is turned over, and before the magnetron sputtering table sputters a layer of metal titanium or titanium-tungsten alloy on the other side of the silicon carbide substrate 10 and then sputters a layer of metal copper, the magnetron sputtering table is turned on and the equipment inspection of the magnetron sputtering table is performed to ensure that the magnetron sputtering table can operate normally. The equipment inspection of the magnetron sputtering table is performed before operation to improve process safety and efficiency and prevent malfunctions during operation that affect processing efficiency.
[0051] The silicon carbide substrate 10 is placed in a magnetron sputtering table, which is turned on. The magnetron sputtering table sputters a layer of metal titanium or titanium-tungsten alloy on one side of the silicon carbide substrate 10 and then sputters a layer of metal copper as a seed layer. After the sputtering is completed, the silicon carbide substrate 10 is turned over. Before the magnetron sputtering table sputters a layer of metal titanium or titanium-tungsten alloy on the other side of the silicon carbide substrate 10 and then sputters a layer of metal copper, the surface of the silicon carbide substrate 10 is cleaned to ensure that there are no impurities on the surface of the silicon carbide substrate, to prevent impurities from being mixed in it during magnetron sputtering, which affects the product quality, resulting in the thermal conductivity being affected, and then affecting the heat dissipation efficiency.
[0052] In this embodiment, after the step of placing the silicon carbide substrate 10 in an electrolytic bath filled with an electrolyte and plating metallic copper on both sides of the silicon carbide substrate 10 in the electrolytic bath, the metallic copper on the silicon carbide substrate 10 is ground and polished, and the surfaces of the first electroplated copper layer 20 and the second electroplated copper layer 30 are polished to achieve the required surface quality, so that the surface roughness reaches Ra less than 0.05 microns.
[0053] In summary, it is easy for those skilled in the art to understand that the present application provides a silicon carbide heat sink structure and a processing technology thereof. The copper-silicon carbide-copper structure in the silicon carbide heat sink structure has a good thermal conductivity. The width of the first electroplated copper layer 20 is smaller than the width of the second electroplated copper layer 30. The chip is made at the edge of the second electroplated copper layer 30 without affecting the scattering of its light, thereby ensuring the power of the chip. The structure is simple and will not cause excessive corrosion to the copper layer, which is more conducive to heat dissipation. The direct copper plating substrate technology DPC (Direct Plating Copper) is used to avoid the influence of high temperature on the material and circuit structure. The thin film and photolithography development technology is used to make the circuit structure on the substrate more refined, with excellent solderability and wire bonding assembly characteristics, which is suitable for precision electronic packaging. The use of copper electroplating will not cause excessive corrosion to the copper layer, which is more conducive to heat dissipation.
[0054] The above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the implementation methods of the present application. For those of ordinary skill in the art, other different forms of changes or modifications can also be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims
1. A silicon carbide heat sink structure, characterized in that: The silicon carbide heat sink structure comprises a silicon carbide substrate (10), a first electroplated copper layer (20), and a second electroplated copper layer (30); the first electroplated copper layer (20) is arranged on the back surface of the silicon carbide substrate (10), and the second electroplated copper layer (30) is arranged on the front surface of the silicon carbide substrate (10); the thickness of the silicon carbide substrate (10) is greater than the thickness of the first electroplated copper layer (20) and the second electroplated copper layer (30); the width of the silicon carbide substrate (10) is greater than the width of the first electroplated copper layer (20) and the second electroplated copper layer (30); the thickness of the first electroplated copper layer (20) is the same as the thickness of the second electroplated copper layer (30), and the width of the first electroplated copper layer (20) is smaller than the width of the second electroplated copper layer (30).
2. The silicon carbide heat sink structure according to claim 1, characterized in that: The silicon carbide heat sink structure comprises a seed layer, the seed layer is arranged on the front side and the back side of the silicon carbide substrate (10), and the seed layer is respectively arranged between the first electroplated copper layer (20), the second electroplated copper layer (30) and the silicon carbide substrate (10).
3. The silicon carbide heat sink structure according to claim 2, characterized in that: The seed layer is a titanium-tungsten alloy metal mixture.
4. The silicon carbide heat sink structure according to claim 1, characterized in that: The thickness of the silicon carbide substrate (10) is 0.3-0.6 millimeters, and the thickness of the first electroplated copper layer (20) and the second electroplated copper layer (30) is 0.002-0.09 millimeters.
5. The silicon carbide heat sink structure according to claim 4, characterized in that: The thickness of the first electroplated copper layer (20) and the second electroplated copper layer (30) is 0.002-0.09 millimeters.
6. The silicon carbide heat sink structure according to claim 1, characterized in that: A circuit layer (40) is provided on the second electroplated copper layer (30).