Heat dissipation structure, preparation method thereof and IGBT module

Abstract

The present invention relates to the field of semiconductors, and in particular to a heat dissipation structure, a preparation method thereof, and an IGBT module. The preparation method of the heat dissipation structure provided in the present application comprises: obtaining a heat sink to be combined based on a blind groove opened on one side of the heat sink in the thickness direction; stacking and bonding a metal sheet and a ceramic substrate and firing them to metalize the ceramic substrate; patterning the surface of the metal layer in the thickness direction so that the ceramic layer has an exposed surface in the thickness direction, and the metal layer on the exposed surface forms a metal boss that can match the blind groove; installing the metal boss on the substrate to be combined in the blind groove of the heat sink to be combined, and bonding the exposed surface to the surface of the heat sink to be combined to form a combination, and sintering and curing the combination to obtain a heat dissipation structure. The heat dissipation structure prepared by the preparation method of the present application can effectively reduce the number of thermal resistance interface layers, improve the heat dissipation efficiency of the IGBT chip, and significantly reduce the production cost and process complexity.

Description

Technical Field

[0001] The present invention relates to the field of semiconductors, and in particular to a heat dissipation structure, a preparation method thereof and an IGBT module. Background Art

[0002] Metallized ceramic substrates are widely used in IGBT chip packaging to provide mechanical support, electrical interconnection, and insulation and heat dissipation functions for the IGBT chip.

[0003] Traditional IGBT modules (such as Figure 1 As shown in FIG. 1 , the metallized ceramic substrate is composed of a ceramic substrate and a metal layer attached to both sides of the ceramic substrate. The metal layers on both sides of the ceramic substrate are connected to the IGBT chip and the heat sink through the brazing layer, respectively. The metallized ceramic substrate and the heat sink together constitute the heat dissipation structure of the IGBT chip. During operation, the heat emitted by the IGBT chip is mainly dissipated vertically. Since there is a brazing layer between the heat sink and the metallized ceramic substrate, the heat of the IGBT chip needs to pass through at least 6 layers of thermal resistance interface layers (i.e., interfaces of different material layers) to transfer the heat to the heat sink. Since the crystal structures of different materials in the thermal resistance interface layer are quite different, there will be a large number of defects in the interface. In addition, there will be a large number of voids in the metal liquid phase in the thermal resistance interface layer after solidification, and the segregation of components will also be formed, which will cause the heat to be scattered in the thermal resistance interface layer during the transmission process, hindering the transmission of heat.

[0004] In order to improve the heat dissipation efficiency of IGBT chips, the existing technology adopts a high thermal conductivity heat sink or ceramic material to assemble a packaging structure, or adopts a more complex liquid cooling channel structure design in the packaging structure. However, these methods will undoubtedly significantly increase the cost of the product and the complexity of the process, and the improvement of the heat dissipation efficiency of the IGBT chip is relatively limited.

[0005] In view of the above, the present invention is proposed. Summary of the invention

[0006] The present application provides a heat dissipation structure, a preparation method thereof and an IGBT module, aiming to solve the above-mentioned problems or at least alleviate the defects existing in the above-mentioned prior art.

[0007] A first aspect of the present application provides a method for preparing a heat dissipation structure, wherein the heat dissipation structure is used for dissipating heat after an IGBT chip is connected, comprising the following steps:

[0008] A heat sink pre-treatment step is performed to form a blind groove of a preset depth on at least one side of the heat sink along the thickness direction to obtain a heat sink to be combined;

[0009] The metallized ceramic substrate preparation process comprises pre-treating the metal sheet and the ceramic substrate, laminating and firing them to obtain a metallized ceramic substrate having a ceramic layer and a metal layer in a thickness direction;

[0010] The substrate pre-treatment step is to pattern the surface of the metal layer along the thickness direction so that the ceramic layer has an exposed surface along the thickness direction, and the metal layer on the exposed surface forms a metal boss that can match the blind groove, and the surface of the metal boss is subjected to a first surface treatment to obtain a substrate to be bonded;

[0011] In the integration process, the metal boss on the substrate to be combined is installed in the blind groove of the heat sink to be combined, and the exposed surface is bonded to the surface of the heat sink to be combined to form a combination, and the combination is sintered and cured to obtain a heat dissipation structure.

[0012] In some embodiments, the patterning process includes: sequentially performing masking, exposure and development on the surface of the metal layer, so that part of the surface of the metal layer is exposed to the mask along the thickness direction according to a preset path, and then performing full etching on the metal layer exposed to the mask portion, so that the ceramic layer has an exposed surface along the thickness direction, and the metal layer on the exposed surface forms a metal boss that can match the blind groove; performing mask removal on the surface of the metal boss, and obtaining the substrate to be combined after the first surface treatment.

[0013] In some embodiments, the preparation method satisfies any one of the following conditions:

[0014] (1) After the full etching process, a plurality of metal bosses are arranged in an array on the surface of the ceramic layer, and after the mask removal process, the exposed surface of the ceramic layer is cut along the thickness direction to form a line groove, and after the first surface treatment, a splitting process is performed based on the line groove to obtain a plurality of substrates to be bonded;

[0015] (2) When the metal layer is aluminum and the heat sink is copper, the heat sink pre-treatment process further includes performing a second surface treatment on the surface of the blind groove; the second surface treatment includes plating nickel on the surface of the blind groove to form a nickel layer;

[0016] (3) When both the metal layer and the heat sink are made of aluminum, the heat sink pre-treatment process further includes performing a second surface treatment on the surface of the blind groove; the second surface treatment includes removing the oxide layer on the surface of the blind groove, and / or providing a transition film containing aluminum or aluminum alloy on the surface of the blind groove;

[0017] (4) When both the metal layer and the heat sink are copper, the heat sink pre-treatment process further includes performing a second surface treatment on the surface of the blind groove; the second surface treatment includes performing an oxidation treatment on the surface of the blind groove to form a copper oxide layer;

[0018] (5) When the metal layer is copper, the first surface treatment includes oxidizing the surface of the metal boss to form a copper oxide layer;

[0019] (6) When the metal layer is aluminum, the first surface treatment includes removing the oxide layer on the surface of the metal boss and / or providing a transition film containing aluminum or aluminum alloy on the surface of the metal boss;

[0020] (7) When the metal layer is copper, the sintering and curing treatment is carried out under nitrogen protection; or, when the metal layer is aluminum, the sintering and curing treatment is carried out in a vacuum environment.

[0021] In some embodiments, the oxidation treatment includes wet oxidation or dry oxidation; wherein, wet oxidation introduces oxygen elements onto the copper surface through chemical reagents, and dry oxidation forms a copper oxide layer by oxidizing the copper surface in a weak oxygen environment.

[0022] In some embodiments, in the process of preparing the metallized ceramic substrate, the pretreatment includes:

[0023] When the metal sheet is copper, the metal sheet is cleaned and oxidized, and the ceramic substrate is cleaned and / or surface-modified; or, when the metal sheet is aluminum, the metal sheet and the ceramic substrate are cleaned separately, and a transition metal or non-metallic film is formed on the surface of the cleaned metal sheet or ceramic substrate.

[0024] In some embodiments, the preparation method satisfies at least one of the following conditions:

[0025] A. In the heat sink pre-treatment process, the preset depth is less than or equal to the thickness of the metal layer;

[0026] B. In the heat sink pre-treatment process, blind grooves of preset depth are respectively opened on both sides of the heat sink to be combined along the thickness direction, and the blind grooves on both sides of the heat sink to be combined are aligned along the thickness direction;

[0027] C. In the integration process, the assembly is installed in a positioning mold for sintering and curing;

[0028] D. The integration process also includes vertically symmetrically cutting the heat sink along the thickness direction based on the assembly after sintering and curing to obtain a heat dissipation structure;

[0029] F. The raw material of the metal sheet is a single metal or an alloy obtained by combining multiple metals; optionally, the metal sheet includes at least one metal element selected from copper, aluminum or nickel;

[0030] G. The ceramic substrate includes any one of a ceramic alumina ceramic substrate, an aluminum nitride ceramic substrate, a zirconia toughened alumina ceramic substrate, a silicon nitride ceramic substrate or a silicon carbide ceramic substrate.

[0031] In some embodiments, the integration process also includes opening a plurality of through holes arranged vertically at intervals along the thickness direction on the thickness surface of the heat sink based on the assembly after sintering and curing treatment, and vertically symmetrically cutting the heat sink along the thickness direction to form a fan-wing structure on the surface of the heat sink.

[0032] In some embodiments, the positioning mold includes a shell, the shell is formed with a receiving groove, and at least one supporting groove is formed at the bottom of the receiving groove, the supporting groove is used to accommodate and support the metal boss on the side of the assembly facing away from the heat sink, and the receiving groove is used to accommodate the assembly and support the heat sink; wherein the inner surface of the shell is sprayed with inorganic isolation powder; the shell is made of silicon carbide or silicon nitride.

[0033] The second aspect of the present application provides a heat dissipation structure, which is prepared by the preparation method as described above, and the heat dissipation structure includes a metallized ceramic substrate and a heat sink; the metallized ceramic substrate includes a ceramic layer and a metal layer bonded to the surface of the ceramic layer, and the metal layer is used to bond and connect the IGBT chip along the thickness direction; the heat sink is bonded and connected to the side of the ceramic layer facing away from the metal layer and is integrated into one.

[0034] The third aspect of the present application provides an IGBT module, comprising the above heat dissipation structure, a soldering layer and an IGBT chip, wherein two sides of the soldering layer along the thickness direction are respectively connected to the metal layer surfaces of the IGBT chip and the heat dissipation structure.

[0035] Compared with the prior art, the heat dissipation structure, preparation method thereof and IGBT module provided in the present application have at least the following beneficial effects:

[0036] The present application optimizes the design of the preparation method of the heat dissipation structure. In the heat sink pre-treatment process, a blind groove of a preset depth is opened on at least one side of the heat sink along the thickness direction, so as to facilitate matching with the metal boss on the subsequent metallized ceramic substrate and provide a precise docking and bonding surface; in the metallized ceramic substrate preparation process, the metal sheet and the ceramic substrate are pre-treated separately to ensure that the two are tightly combined after firing to form a metallized ceramic substrate with a ceramic layer and a metal layer; in the substrate pre-treatment process, a metal boss that can match the blind groove is formed on the exposed surface of the ceramic layer by patterning based on the metal layer, and the patterning process can accurately control the shape of the metal boss The degree of fit is appropriate to facilitate the precise docking between the metal boss and the blind groove. The first surface treatment on the surface of the metal boss can enhance the bonding strength between the metal boss and the blind groove. In the integration process, the metal boss on the substrate to be combined is installed in the blind groove of the heat sink to be combined, so that the exposed surface and the surface of the heat sink are bonded to form a combination to achieve precise docking and preliminary bonding between the metallized ceramic substrate and the heat sink. The combination is then sintered and cured to fuse the metal boss into the blind groove. In the resulting heat dissipation structure, the ceramic layer is directly bonded to the surface of the heat sink, and there is no excess metal layer and brazing layer between the ceramic layer and the heat sink. The heat dissipation structure has high heat dissipation efficiency and overall stability.

[0037] Therefore, through the matching installation and sintering and curing treatment of the metal boss and the blind groove, there is no extra metal layer and brazing layer between the ceramic layer and the heat sink of the heat dissipation structure, and the surface of the ceramic layer is directly bonded to the surface of the heat sink, which effectively reduces the number of thermal resistance interface layers, reduces the scattering and obstruction in the heat transfer process, and enables heat to be more efficiently transferred from the IGBT chip to the heat sink, thereby improving the heat dissipation efficiency; compared with traditional processes, the preparation method provided in the present application starts from the nature of heat obstruction, so that the at least 6 layers of thermal resistance interface layers that the heat of the IGBT chip needs to pass through to transfer to the heat sink are reduced to 4 layers, and the heat dissipation efficiency of the IGBT chip can be effectively improved without the use of high thermal conductivity materials or complex liquid cooling channel designs, thereby significantly reducing production costs and process complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 It is a structural schematic diagram of an IGBT module in the prior art;

[0040] Figure 2 A flow chart of a metallized ceramic substrate preparation process and a substrate pre-treatment process provided as an example in an embodiment of the present application;

[0041] Figure 3 A flow chart of a heat sink pre-treatment process exemplarily provided in an embodiment of the present application;

[0042] Figure 4 A flowchart of an integrated process provided as an example of an embodiment of the present application;

[0043] Figure 5 A flowchart of an integrated process provided as an example for another embodiment of the present application;

[0044] Figure 6 A schematic diagram of the positioning mold and the assembly provided as an example in the embodiment of the present application when they are matched;

[0045] Figure 7 A schematic diagram of the structure of an IGBT module exemplarily provided in an embodiment of the present application.

[0046] Reference numerals:

[0047] 100. Heat dissipation structure;

[0048] 10. Heat sink; 11. Blind slot; 12. Through hole; 13. Fan-fin structure;

[0049] 20. Ceramic layer; 21. Ceramic substrate; 22. Exposed surface;

[0050] 30. metal layer; 31. metal sheet; 32. metal boss;

[0051] 200, brazing layer;

[0052] 300, IGBT chip;

[0053] 400, positioning mold; 410, housing; 411, receiving groove; 412, supporting groove;

[0054] 1000, IGBT module;

[0055] 1. Mask; 2. Oxide layer; 3. Substrate to be bonded; 4. Heat sink to be bonded; 5. Assembly. DETAILED DESCRIPTION

[0056] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0057] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0058] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0059] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0060] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0061] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0062] The term "heat sink 10" in this application refers to an object that can efficiently absorb, conduct and dissipate heat, and its temperature will not change significantly due to the amount of heat energy absorbed. The heat sink 10 conducts heat from a heat source (such as electronic components, chips, etc.) to a larger heat dissipation area through its high thermal conductivity material (such as copper, aluminum, etc.), thereby achieving heat dissipation.

[0063] The term "blind groove 11" in this application refers to a groove structure opened on the surface of the material and does not penetrate the entire thickness of the material. The blind groove 11 does not penetrate the entire thickness of the material, that is, it has a certain depth inside the material but does not reach the other side of the material.

[0064] The term "patterning process" in this application refers to a process of processing the surface of a material into a pattern with a specific shape, size, arrangement, etc., which may include a combination of multiple process steps such as masking 1, exposure, development, etching, deposition and laser cutting.

[0065] The term "full etching treatment" in this application refers to the use of chemical solutions or physical energy (such as plasma, laser, etc.) to corrode the target area on the surface of the metal layer 30. After the corrosion treatment, the metal layer 30 in the target area is completely removed, so that the ceramic layer 20 can be exposed through the target area.

[0066] The term "mask 1" in the present application refers to a protective film covering the surface of a material, which is used to protect or isolate a specific area to prevent the specific area from being affected by the outside or participating in the processing process.

[0067] As mentioned above, Figure 1 It is a structural schematic diagram of an IGBT module 1000 in the prior art. The metallized ceramic substrate is composed of a ceramic substrate 21 and a metal layer 30 adhered to both sides of the ceramic substrate 21. The metal layers 30 on both sides of the ceramic substrate 21 are respectively connected to the IGBT chip 300 and the heat sink 10 through the brazing layer 200. The metallized ceramic substrate and the heat sink 10 together constitute the heat dissipation structure 100 of the IGBT chip 300. Due to the brazing layer 200 between the heat sink 10 and the metallized ceramic substrate, the heat of the IGBT chip 300 needs to pass through at least 6 layers of thermal resistance interface layers to be transferred to the heat sink 10, and the heat dissipation efficiency is poor.

[0068] In this regard, the general inventive concept of the embodiment of the present application is to optimize the design of the heat dissipation structure 100 and the preparation method thereof. In the preparation method of the heat dissipation structure 100, a design based on matching the metal boss 32 on the metallized ceramic substrate with the blind groove 11 on the heat sink 10 is adopted to achieve precise docking between the two and a firm combination of sintering and curing treatment. In the obtained heat dissipation structure 100, the ceramic layer 20 can directly conduct heat to the heat sink 10, thereby reducing the number of thermal resistance interface layers, reducing the scattering and obstruction of heat during the transmission process, and significantly improving the heat dissipation efficiency of the IGBT chip 300 while avoiding an increase in production cost and process complexity.

[0069] Based on the above general inventive concept, Figure 2-7 As shown, the embodiment of the present application provides a method for preparing a heat dissipation structure 100, the heat dissipation structure 100 is used for dissipating heat after the IGBT chip 300 is connected, and includes the following steps:

[0070] The heat sink 10 is pre-treated by forming a blind groove 11 with a preset depth on at least one side of the heat sink 10 along the thickness direction, thereby obtaining a heat sink 4 to be combined;

[0071] The metallized ceramic substrate preparation step is to pre-treat the metal sheet 31 and the ceramic substrate 21, stack them, and then sinter them to obtain a metallized ceramic substrate having a ceramic layer 20 and a metal layer 30 along the thickness direction;

[0072] In the substrate pre-treatment step, a patterning treatment is performed on the surface of the metal layer 30 along the thickness direction, so that the ceramic layer 20 has an exposed surface 22 along the thickness direction, and the metal layer 30 on the exposed surface 22 forms a metal boss 32 that can match the blind groove 11, and a first surface treatment is performed on the surface of the metal boss 32 to obtain a substrate 3 to be bonded;

[0073] In the integration process, the metal boss 32 on the substrate 3 to be combined is installed in the blind groove 11 of the heat sink 4 to be combined, and the exposed surface 22 is attached to the surface of the heat sink 4 to be combined to form a combination 5, and the combination 5 is sintered and cured to obtain the heat dissipation structure 100.

[0074] Understandable, reference Figure 3 As shown, in the pre-treatment process of the heat sink 10 of the embodiment of the present application, the heat sink 10 can be a plate-shaped piece, and a blind groove 11 of a preset depth is opened on at least one side of the heat sink 10 along the thickness direction. The depth of the blind groove 11 is adapted to the thickness of the metal layer 30 on the ceramic layer 20 to ensure that after the subsequent metal boss 32 is installed in the blind groove 11, the exposed surface 22 of the ceramic layer 20 can fit tightly with the surface of the heat sink 10.

[0075] The specific processing method of the blind groove 11 in this embodiment can be physical, chemical, mechanical processing and other conventional means, wherein the chemical means can etch the blind groove 11 through chemical liquid, and the mechanical processing includes but is not limited to CNC (computer numerical control) and conventional material forming means.

[0076] Continue to refer Figure 2 In the preparation process of the metallized ceramic substrate of the present embodiment, the metal sheet 31 and the ceramic substrate 21 are pre-treated respectively, which can promote the metal sheet 31 and the ceramic substrate 21 to be tightly combined after being stacked and fired, so as to obtain a metallized ceramic substrate having a ceramic layer 20 and a metal layer 30 along the thickness direction; further in the substrate pre-treatment process, the metal layer 30 of the metallized ceramic substrate is subjected to patterning treatments such as masking 1, exposure, development and etching, which can remove part of the metal layer 30 on the surface of the ceramic layer 20, so that the ceramic layer 20 is exposed to the metal layer 30 along the thickness direction (i.e., an exposed surface 22 is formed), and the metal layer 30 forms a metal boss 32 that can match the blind groove 11, and then the surface of the metal boss 32 is subjected to a first surface treatment, so that after the subsequent assembly 5 is sintered and solidified, the metal boss 32 of the substrate 3 to be combined with the blind groove 11 can be tightly combined and integrated.

[0077] refer to Figure 4 As shown, in the integration process, the metal boss 32 on the substrate 3 to be combined is installed in the blind groove 11 of the heat sink 4 to be combined, the surface of the metal boss 32 is in contact with and fits with the surface of the blind groove 11, and the exposed surface 22 of the ceramic layer 20 is fit with the surface of the heat sink 10 to form a combination 5, so as to achieve precise docking and preliminary bonding between the metallized ceramic substrate and the heat sink 10, and then through sintering and curing treatment, the contact surface between the metal boss 32 and the blind groove 11 is metallurgically bonded to form an integrated structure, thereby obtaining the heat dissipation structure 100.

[0078] As a result, the surface of the ceramic layer 20 is directly bonded to the surface of the heat sink 10, and there is no redundant metal layer 30 and brazing layer 200 between the ceramic layer 20 of the heat dissipation structure 100 and the heat sink 10, which effectively reduces the number of thermal resistance interface layers, reduces scattering and obstruction in the heat transfer process, and enables heat to be more efficiently transferred from the IGBT chip 300 to the heat sink 10, thereby significantly improving the heat dissipation efficiency and significantly reducing the production cost and process complexity.

[0079] It should be noted that the heat sink 10 in the embodiment of the present application can be made of a metal material such as copper or aluminum that has a high thermal conductivity and is easy to process.

[0080] In addition, the metallized ceramic substrate obtained by the metallized ceramic substrate preparation process in the embodiment of the present application can be any one of a direct copper-bonded ceramic substrate 21 (Direct Bonded Copper, DBC), a direct aluminum-bonded ceramic substrate 21 (Direct Bonded Aluminum, DBA), and an active metal brazing substrate (Active Metal Brazing, AMB).

[0081] It should be understood that, based on different production requirements, in the pre-treatment process of the heat sink 10 in the embodiment of the present application, the blind groove 11 can be opened on a single side of the heat sink 10 along the thickness direction, or on both sides of the heat sink 10 along the thickness direction; at the same time, any surface of the heat sink 4 to be combined along the thickness direction can have one blind groove 11, or can have multiple blind grooves 11.

[0082] In addition, based on different production requirements, in the preparation process of the metallized ceramic substrate in the embodiment of the present application, the metal sheet 31 can be one or two. When there is one metal sheet 31, the metal sheet 31 is laminated on one side of the ceramic substrate 21 along the thickness direction, and the obtained metallized ceramic substrate has only a single metal layer 30; when there are two metal sheets 31, the metal sheets 31 are laminated on both sides of the ceramic substrate 21 along the thickness direction, and the ceramic substrate 21 is laminated between the two metal sheets 31 (such as Figure 2 As shown in FIG. 1 ), the obtained metallized ceramic substrate has two metal layers 30, and the ceramic layer 20 is located between the two metal layers 30 along the thickness direction. When there are two metal sheets 31, the two metal sheets 31 can be made of the same material (for example, both are copper) or different materials (for example, one metal sheet 31 is copper and the other metal sheet 31 is aluminum).

[0083] In some embodiments, the patterning process includes: sequentially performing mask 1 treatment, exposure treatment and development treatment on the surface of the metal layer 30, so that part of the surface of the metal layer 30 is exposed to the mask 1 along the thickness direction according to a preset path, and then the metal layer 30 exposed to the mask 1 is fully etched to make the ceramic layer 20 have an exposed surface 22 along the thickness direction, and the metal layer 30 on the exposed surface 22 forms a metal boss 32 that can match the blind groove 11; the surface of the metal boss 32 is demasked 1, and the substrate 3 to be combined is obtained after the first surface treatment.

[0084] The patterning process in this embodiment determines the shape and position of the metal boss 32 on the metallized ceramic substrate, thereby affecting the matching degree with the blind groove 11 on the heat sink 10. In the patterning process of this embodiment, the surface of the metal layer 30 is sequentially subjected to mask 1 treatment, exposure treatment and development treatment. The mask 1 treatment is to attach a layer of mask 1 to the surface of the metal layer 30. The function of this mask 1 is to protect the graphic surface part of the metal layer 30 so that it will not be corroded in the subsequent full etching process. The pattern and size of the mask 1 can be determined according to the design of the blind groove 11 to ensure that the metal boss 32 can accurately match the blind groove 11. When the metal layer 30 with the mask 1 is exposed, the pattern is projected onto the mask 1 through a specific exposure device, and the exposed part of the mask 1 will undergo chemical changes. In the development process, a developer is used to remove the easily soluble part of the mask 1 after exposure, so that the metal layer 30 can be exposed along a preset path. The metal layer 30 on the preset path is the part that is subsequently fully etched.

[0085] By fully etching the metal layer 30 exposed to the mask 1, the etching solution will corrode the part of the metal layer 30 not protected by the mask 1, while the metal layer 30 under the mask 1 is retained. In this way, a metal boss 32 matching the shape of the blind groove 11 is formed on the metal layer 30, and the corresponding surface (i.e., the exposed surface 22) is exposed on the ceramic layer 20.

[0086] After the metal boss 32 is formed on the ceramic layer 20, the surface of the metal boss 32 can be demasked 1 using chemical solvents or physical methods, such as peeling or wiping, to ensure that the surface of the metal boss 32 is clean and there is no residue of the mask 1; then the surface of the metal boss 32 is subjected to a first surface treatment to enable the metal boss 32 to be tightly combined with the blind groove 11 of the substrate 3 to be bonded and integrated after the subsequent sintering and curing treatment of the assembly 5.

[0087] refer to Figure 2In some embodiments, in order to obtain a plurality of substrates 3 to be combined with metal bosses 32, after full etching treatment, a plurality of metal bosses 32 are arranged in an array on the surface of the ceramic layer 20, and after mask removal 1 treatment, the exposed surface 22 of the ceramic layer 20 is cut along the thickness direction, and a line groove is formed on the exposed surface 22 of the ceramic layer 20, and after the first surface treatment, a splitting treatment is performed based on the line groove to obtain a plurality of substrates 3 to be combined.

[0088] It can be understood that the cutting process is performed on the exposed surface 22 of the ceramic layer 20, and the purpose is to split the overall structure into multiple independent units along the preset cutting grooves. These grooves are usually determined according to the array layout of the metal bosses 32 to ensure that each unit contains at least one metal boss 32. The cutting process of the exposed surface 22 of the ceramic layer 20 can be achieved by laser cutting, mechanical cutting or other high-precision cutting techniques; in addition, the splitting process is performed on the basis of the grooves formed by the cutting process, and the purpose is to completely separate the overall structure along the cutting position into multiple independent substrates 3 to be combined. The splitting process can be achieved by mechanical splitting or thermal splitting. After the splitting process, each substrate 3 to be combined has a complete metal boss 32 and a portion of the ceramic layer 20 connected thereto. Multiple substrates 3 to be combined with metal bosses 32 can be respectively installed in blind grooves 11 at different positions of the heat sink 10 to improve production efficiency.

[0089] When the metallized ceramic substrate in this embodiment is a directly-bonded aluminum ceramic substrate 21 (DBA), the metal boss 32 is made of aluminum. When a copper heat sink 10 is used to match the directly-bonded aluminum ceramic substrate 21, in order to achieve integrated molding of the metal layer 30 and the heat sink 10, in some embodiments, when the metal layer 30 is aluminum and the heat sink 10 is copper, the pre-treatment process of the heat sink 10 also includes performing a second surface treatment on the surface of the blind groove 11, and the second surface treatment includes nickel plating the surface of the blind groove 11 to form a nickel layer.

[0090] It can be understood that due to the large differences in physical and chemical properties between aluminum and copper, direct bonding may lead to interface instability and reduced heat conduction efficiency. Through the second surface treatment, nickel is electroplated or chemically plated on the surface of the blind groove 11 to form a nickel layer. Nickel, as a transition metal, has physical and chemical properties between those of aluminum and copper, which can effectively enhance the bonding force between aluminum and copper, making the metal layer 30 and the heat sink 10 more stable after integrated molding.

[0091] In some embodiments, when an aluminum heat sink 10 is used to match a directly aluminum-coated ceramic substrate 21, the metal layer 30 and the heat sink 10 are both aluminum, and the pre-treatment process of the heat sink 10 also includes performing a second surface treatment on the surface of the blind groove 11, and the second surface treatment includes removing the oxide layer on the surface of the blind groove 11, and / or setting a transition film containing aluminum or aluminum alloy on the surface of the blind groove 11 (not shown).

[0092] Since the surface of the aluminum heat sink 10 is oxidized in the air to form an aluminum oxide layer, by removing the oxide layer, the pure aluminum surface of the heat sink 10 can be exposed, so as to improve the bonding quality with the metal boss 32. Then, according to the subsequent process requirements, it is selected whether to form a layer of aluminum or aluminum alloy transition film at the position of the blind groove 11 to improve wettability and reduce interface energy, so as to promote the tight bonding between the aluminum heat sink 10 and the aluminum metal boss 32 after sintering and curing treatment. In some embodiments, aluminum or aluminum alloy (such as Al-Si alloy) solder or welding sheet can also be directly arranged on the surface of the blind groove 11 after removing the oxide layer, which can improve the wettability of the aluminum metal boss 32 and the aluminum heat sink 10 when they are combined after sintering and curing treatment, so as to promote the integrated molding of the two.

[0093] In some embodiments, when the metallized ceramic substrate is a direct-bonded copper ceramic substrate 21 (DBC), the metal boss 32 is made of copper. When a copper heat sink 10 is used to match the direct-bonded copper ceramic substrate 21, the metal layer 30 and the heat sink 10 are both made of copper. The pre-treatment process of the heat sink 10 also includes performing a second surface treatment on the surface of the blind groove 11. The second surface treatment includes oxidizing the surface of the blind groove 11 to form a copper oxide layer, so as to facilitate the metallurgical bonding with the copper metal boss 32 during the sintering and curing process, thereby promoting the integrated molding of the metallized ceramic substrate and the heat sink 10.

[0094] In some embodiments, when the metallized ceramic substrate is a direct copper-clad ceramic substrate 21, the metal layer 30 is copper, and the first surface treatment includes oxidizing the surface of the metal boss 32 to form a copper oxide layer 2, so as to facilitate the metallurgical bonding with the blind groove 11 during the sintering and curing process, thereby promoting the integrated molding of the metallized ceramic substrate and the heat sink 10.

[0095] In some embodiments, when the metallized ceramic substrate is a directly aluminum-coated ceramic substrate 21, the metal layer 30 is aluminum, and the first surface treatment includes removing the oxide layer on the surface of the metal boss 32, and / or providing a transition film containing aluminum or an aluminum alloy on the surface of the metal boss 32; the metal boss 32 formed by the aluminum metal layer 30 is oxidized in the air to form an aluminum oxide layer on the surface, and by removing the oxide layer, a pure aluminum surface can be exposed, so as to improve the bonding quality with the heat sink 10, and then, according to the subsequent process requirements, it is selected whether to form a layer of aluminum or an aluminum alloy transition film on the surface of the metal boss 32 to improve wettability and reduce interface energy, so as to promote the tight bonding between the aluminum metal boss 32 and the heat sink 10 after sintering and curing.

[0096] In some embodiments, when the metallized ceramic substrate is a direct copper-clad ceramic substrate 21, the metal layer 30 is copper, and the sintering and curing treatment is carried out under nitrogen protection. Nitrogen is an inert gas that can effectively prevent copper from reacting with oxygen in the air at high temperatures, thereby avoiding oxidation and corrosion. For example, the assembly 5 can be placed in a continuous furnace (tunnel furnace) protected by nitrogen for sintering and curing; or, when the metallized ceramic substrate is a direct aluminum-clad ceramic substrate 21, the metal layer 30 is aluminum. Since aluminum easily reacts with oxygen at high temperatures to form aluminum oxide, the sintering and curing treatment is usually carried out in a vacuum environment. The vacuum environment can effectively remove oxygen and other impurities in the air. For example, the assembly 5 can be placed in a vacuum furnace for sintering and curing.

[0097] In some embodiments, when the blind groove 11 and / or the metal boss 32 are copper, an oxidation treatment is required on the surface, and the oxidation treatment includes wet oxidation or dry oxidation; wherein, the wet oxidation introduces oxygen elements to the copper surface through chemical reagents, and the dry oxidation forms a copper oxide layer 2 by oxidizing the copper surface in a weak oxygen environment, so as to facilitate the close bonding between the blind groove 11 and the metal boss 32 during sintering and solidification.

[0098] In some embodiments, in the preparation process of the metallized ceramic substrate, the pretreatment includes: when the metal sheet 31 is copper, cleaning and oxidizing the metal sheet 31, and cleaning and / or surface modifying the ceramic substrate 21; or, when the metal sheet 31 is aluminum, cleaning the metal sheet 31 and the ceramic substrate 21 respectively, and forming a transition metal or non-metallic film on the surface of the cleaned metal sheet 31 or the ceramic substrate 21.

[0099] It can be understood that for the prepared metallized ceramic substrate which is a direct copper-clad ceramic substrate 21, the metal sheet 31 is copper. In order to promote the close bonding between the metal sheet 31 and the ceramic substrate 21, the metal sheet 31 is cleaned to remove impurities such as oil, dust, etc. on the surface of the metal sheet 31, and the surface of the metal sheet 31 is further oxidized to form a copper oxide layer to facilitate enhancing the bonding force between copper and the ceramic substrate 21 to ensure the close bonding between the metal sheet 31 and the ceramic substrate 21; at the same time, the ceramic substrate 21 is cleaned to remove impurities and pollutants on the surface. If necessary, the ceramic substrate 21 can also be surface-modified, such as nickel plating or other transition metals to improve the wetting properties and improve its bonding ability with the metal sheet 31.

[0100] In addition, when the metal sheet 31 is aluminum, the metal sheet 31 and the ceramic substrate 21 are cleaned separately to remove impurities such as oil and dust on the surface, and a layer of transition metal or non-metallic film is formed on the surface of the cleaned metal sheet 31 or the ceramic substrate 21. The transition metal film (such as nickel, chromium, etc.) or non-metallic film (such as silicon dioxide, aluminum oxide, etc.) can serve as a "bridge" between aluminum and the ceramic substrate 21 to improve the wettability and bonding between them.

[0101] In some embodiments, in the pre-treatment process of the heat sink 10, the preset depth is less than or equal to the thickness of the metal layer 30. The preset depth refers to the depth of the blind groove 11 and the thickness of the metal boss 32. The preset depth is less than or equal to the thickness of the metal layer 30, which is conducive to the metal boss 32 formed by the metal layer 30 being installed in the blind groove 11, so that the exposed surface 22 of the ceramic layer 20 can fit tightly with the surface of the heat sink 10.

[0102] In some embodiments, in the pre-treatment process of the heat sink 10, blind grooves 11 of a preset depth are respectively opened on both sides of the heat sink 4 to be combined along the thickness direction, and the blind grooves 11 on both sides of the heat sink 4 to be combined are aligned along the thickness direction; for example, referring to Figure 3 As shown, two blind grooves 11 are respectively provided on both sides of the heat sink 4 to be combined, and each blind groove 11 on the upper and lower sides is symmetrical along the thickness direction, so as to improve the stability during sintering and curing treatment.

[0103] In some embodiments, the integration process further includes vertically symmetrically cutting the heat sink 10 along the thickness direction based on the assembly 5 after sintering and curing, so as to obtain two sub-heat dissipation structures 100, so as to improve production efficiency.

[0104] In some embodiments, the raw material of the metal sheet 31 is a single metal or an alloy obtained by combining multiple metals; optionally, the metal sheet 31 includes at least one metal element selected from copper, aluminum or nickel.

[0105] In some embodiments, the ceramic substrate 21 includes an alumina ceramic substrate. (Al2O3) , aluminum nitride ceramic substrate (AlN), zirconia toughened alumina ceramic substrate (ZTA), silicon nitride ceramic substrate (Si3N4) , any one of silicon carbide ceramic substrates (SiC).

[0106] In some embodiments, reference Figure 6 As shown, in the integration process, the assembly 5 is installed in the positioning mold 400 for sintering and curing treatment. The positioning mold 400 provides an accurate positioning reference and support structure for the assembly 5. During the sintering and curing process, the assembly 5 can be stably placed in the positioning mold 400 and supported by the positioning mold 400 to prevent the heat sink 10 from deforming. At the same time, quality problems caused by position movement or shape changes are avoided, thereby improving product reliability.

[0107] In some embodiments, the integration process also includes, based on the assembly 5 after sintering and curing treatment, opening a plurality of through holes 12 arranged vertically at intervals along the thickness direction on the thickness surface of the heat sink 10, and dividing the heat sink 10 vertically symmetrically along the thickness direction to obtain two heat dissipation structures 100, and a fan-fin structure 13 is formed on the side of the heat sink 10 of each heat dissipation structure 100 away from the ceramic substrate 21, and the fan-fin structure 13 is a groove arranged vertically at intervals along the thickness direction, thereby greatly increasing the heat dissipation area of ​​the heat sink 10, so as to further improve the heat dissipation efficiency of the IGBT chip 300.

[0108] In a specific embodiment, the positioning mold 400 includes a shell 410, the shell 410 is formed with a receiving groove 411, and at least one supporting groove 412 is formed at the bottom of the receiving groove 411, the supporting groove 412 is used to accommodate and support the metal boss 32 on the side of the assembly 5 facing away from the heat sink 10, and the receiving groove 411 is used to accommodate the assembly 5 and support the heat sink 10; wherein, the inner surface of the shell 410 is sprayed with inorganic isolation powder, and the inorganic isolation powder does not undergo any chemical reaction with the metal and the mold to prevent the heat dissipation structure 100 and the mold from sticking together during demolding.

[0109] Furthermore, the shell 410 is made of a material with small heat capacity, high thermal conductivity, no oxygen absorption, and no reaction with metal and ceramic at high temperature. For example, the shell 410 is made of silicon carbide or silicon nitride.

[0110] It should be understood that the positioning mold 400 used in the present application can be flexibly designed according to the shape of the assembly 5 for the purpose of supporting and stabilizing the assembly 5, and its structure is not limited to that illustrated in this embodiment.

[0111] refer to Figure 7 Another embodiment of the present application provides a heat dissipation structure 100, which is manufactured by the above-mentioned manufacturing method. The heat dissipation structure 100 includes a metallized ceramic substrate and a heat sink 10; the metallized ceramic substrate includes a ceramic layer 20 and a metal layer 30 bonded to the surface of the ceramic layer 20, and the metal layer 30 is used to bond and connect an IGBT chip 300 along the thickness direction; the heat sink 10 is bonded and connected to a side of the ceramic layer 20 away from the metal layer 30 and is formed as an integrated whole.

[0112] It should be noted that the metallized ceramic substrate originally has two metal layers 30. In the heat dissipation structure 100 of this embodiment, one of the metal layers 30 of the metallized ceramic substrate is sintered and solidified with the blind groove 11 of the heat sink 10, so that the heat sink 10 and the side of the ceramic layer 20 away from the metal layer 30 are bonded and connected and integrated, and the other metal layer 30 can be used to bond and connect the IGBT chip 300 along the thickness direction. Compared with the traditional technology, the heat dissipation structure 100 provided in the embodiment of the present application has fewer thermal resistance interface layers and has higher heat dissipation efficiency and overall stability.

[0113] Continue to refer Figure 7 As shown, another embodiment of the present application provides an IGBT module 1000, including the above heat dissipation structure 100, a soldering layer 200 and an IGBT chip 300, wherein the two sides of the soldering layer 200 along the thickness direction are respectively connected to the surface of the IGBT chip 300 and the metal layer 30 of the heat dissipation structure 100.

[0114] At this point, in the IGBT module 1000 provided in the embodiment of the present application, when the IGBT chip 300 conducts heat along the thickness direction, the heat only needs to pass through the brazing layer 200, the metal layer 30, and the ceramic layer 20 to reach the heat sink 10. The number of thermal resistance interface layers of the heat dissipation structure 100 is smaller, which effectively suppresses the heat of the IGBT chip 300 from being hindered by scattering of the thermal resistance interface layers, and significantly improves the heat dissipation performance of the IGBT chip 300.

[0115] The following examples describe the disclosure of the present application in more detail, and these examples are merely illustrative, as it will be apparent to those skilled in the art that various modifications and variations are made within the scope of the disclosure of the present application. Unless otherwise stated, all reagents and raw materials used in the examples are commercially available or synthesized according to conventional methods, and the instruments used in the examples are commercially available.

[0116] Example 1

[0117] preparation Al2O3-DBC / Cu Heat dissipation structure 100:

[0118] (1) Pre-treatment process of the heat sink 10: a total of 4 blind grooves 11 are machined on both sides of the copper heat sink 10 to obtain the heat sink 4 to be combined; the specification of the blind groove 11 is: 55*24*0.25 (mm), and the blind grooves 11 on both sides of the heat sink 4 to be combined are symmetrical along the thickness direction;

[0119] (2) Preparation process of metallized ceramic substrate: After two copper sheets and an alumina ceramic substrate 21 are ultrasonically cleaned, the copper sheet is oxidized; the specifications of the copper sheet are 138*184*0.30 (mm), and the specifications of the alumina ceramic substrate 21 are 138*190*0.635 (mm); further, two copper metal sheets 31 are stacked on the surface of the alumina ceramic substrate 21 along the thickness direction and fired to obtain a metallized ceramic substrate having a ceramic layer 20 and two metal layers 30 along the thickness direction;

[0120] (3) Substrate pre-treatment process: After the metallized ceramic substrate is subjected to masking 1 treatment, exposure treatment, development treatment, and full etching treatment in sequence, the surface of the metal layer 30 is etched into a pattern of 55*24 (mm), and a metal boss 32 arranged in a matrix of 5 rows and 3 columns is obtained on the ceramic layer 20, and then the photosensitive film on the surface of the metal boss 32 is removed; further, the surface of the metal boss 32 on one side of the ceramic layer 20 is subjected to secondary oxidation treatment, and the exposed surface 22 of the ceramic layer 20 is cut along the thickness direction to form a wire groove, and then based on the wire groove, it is split into multiple sub-substrates 3 to be combined.

[0121] (4) Integration process: The metal bosses 32 of the four sub-substrates 3 to be bonded are installed in the four blind grooves 11 of the heat sink 4 to be bonded through secondary oxidation, so that the exposed surface 22 of the ceramic layer 20 is bonded to the surface of the heat sink 4 to form a composite body 5. The composite body 5 is placed in a tunnel furnace protected by nitrogen for sintering and curing. Subsequently, the heat sink 10 is cut vertically and symmetrically along the thickness direction by wire cutting to obtain the following: Figure 4 The two shown Al2O3-DBC / Cu Heat dissipation structure 100 .

[0122] Example 2

[0123] Preparation of AlN-DBA / Al heat dissipation structure 100:

[0124] (1) Pre-treatment process of the heat sink 10: a total of 4 blind grooves 11 are machined on both sides of the aluminum heat sink 10, the oxide film on the surface of the blind grooves 11 of the aluminum heat sink 10 is removed, and an aluminum alloy welding sheet (Al-Si alloy) is placed at the bottom of the blind grooves 11 of the aluminum heat sink 10 to obtain the heat sink 4 to be combined; the specifications of the blind grooves 11 are: 60.4*26.8*0.15 (mm), the specifications of the welding sheet are 59.4*25.8*0.05 (mm), and the blind grooves 11 on both sides of the heat sink 4 to be combined are symmetrical along the thickness direction;

[0125] (2) Preparation process of metallized ceramic substrate: After ultrasonic cleaning of two aluminum sheets and aluminum nitride ceramic substrate 21, nickel is plated on the surface of aluminum nitride ceramic substrate 21 to form a transition film; the specifications of the aluminum sheets are 134*184*0.30 (mm), and the specifications of the aluminum nitride ceramic substrate 21 are 138*190*0.635 (mm); further, two aluminum metal sheets 31 are stacked on the surface of aluminum nitride ceramic substrate 21 along the thickness direction and fired to obtain a metallized ceramic substrate having a ceramic layer 20 and two metal layers 30 along the thickness direction;

[0126] (3) Substrate pre-treatment process: After the metallized ceramic substrate is subjected to masking 1 treatment, exposure treatment, development treatment, and full etching treatment in sequence, the surface of the metal layer 30 is etched into a pattern with a size of 60.4*26.8 (mm), and a metal boss 32 arranged in a matrix of 6 rows and 2 columns is obtained on the ceramic layer 20, and then the photosensitive film on the surface of the metal boss 32 is removed; further, the oxide film on the surface of the metal boss 32 on one side of the ceramic layer 20 is removed, and the exposed surface 22 of the ceramic layer 20 is cut along the thickness direction to form a wire groove, and then based on the wire groove, it is split into multiple sub-substrates 3 to be combined.

[0127] (4) Integration process: The four sub-substrates 3 to be combined are installed in the four blind grooves 11 of the heat sink 4 to be combined by removing the metal bosses 32 of the oxide film, so that the exposed surface 22 of the ceramic layer 20 is bonded to the surface of the heat sink 4 to be combined to form a combination 5. The combination 5 is placed in a vacuum furnace for sintering and curing treatment, and then the heat sink 10 is cut vertically symmetrically along the thickness direction by wire cutting to obtain two AlN-DBA / Al heat dissipation structures 100.

[0128] Example 3

[0129] Preparation of ZTA-ACC / Al heat dissipation structure 100:

[0130] (1) Pre-treatment process of the heat sink 10: a total of two blind grooves 11 are machined on both sides of the aluminum heat sink 10, the oxide film on the surface of the blind groove 11 of the aluminum heat sink 10 is removed, and an aluminum alloy welding sheet (Al-Si alloy) is placed at the bottom of the blind groove 11 of the aluminum heat sink 10 to obtain the heat sink 4 to be combined; the specifications of the blind groove 11 are: 25.5*56.5*0.25 (mm), the specifications of the welding sheet are 24.5*55.5*0.05 (mm), and the blind grooves 11 on both sides of the heat sink 4 to be combined are symmetrical along the thickness direction;

[0131] (2) Preparation process of metallized ceramic substrate: After ultrasonic cleaning of the aluminum sheet, copper sheet and zirconia toughened alumina ceramic substrate 21, the surface of the copper sheet is oxidized and the surface of the aluminum sheet is deoxidized; the specifications of the copper sheet and the aluminum sheet are both 134*184*0.30 (mm), and the specifications of the aluminum nitride ceramic substrate 21 are 138*190*0.635 (mm); further, the aluminum sheet and the copper sheet are respectively stacked on the surface of the zirconia toughened alumina ceramic substrate 21 along the thickness direction and fired to obtain a metallized ceramic substrate having a ceramic layer 20 and two metal layers 30 along the thickness direction;

[0132] (3) Substrate pre-treatment process: After the metallized ceramic substrate is subjected to masking 1 treatment, exposure treatment, development treatment, and full etching treatment in sequence, the surface of the metal layer 30 is etched into a pattern with a size of 25.5*56.5 (mm), and a metal boss 32 arranged in a matrix of 3 rows and 5 columns is obtained on the ceramic layer 20, and then the photosensitive film on the surface of the metal boss 32 is removed; further, the oxide film on the surface of the metal boss 32 on both sides of the ceramic layer 20 is removed, and the exposed surface 22 of the ceramic layer 20 is cut along the thickness direction to form a wire groove, and then based on the wire groove, it is split into multiple sub-substrates 3 to be combined.

[0133] (4) Integration process: The two sub-substrates 3 to be combined are installed in the two blind grooves 11 of the heat sink 4 to be combined through the metal bosses 32 with the oxide film removed, so that the exposed surface 22 of the ceramic layer 20 is bonded to the surface of the heat sink 4 to be combined to form a combination 5, and the combination 5 is placed in a vacuum furnace for sintering and curing treatment. Subsequently, a plurality of through holes 12 arranged vertically at intervals along the thickness direction are opened on the thickness surface of the heat sink 10 by wire cutting, and the heat sink 10 is cut vertically symmetrically along the thickness direction to obtain the following. Figure 5 The two heat sinks 10 shown have a ZTA-ACC / Al heat dissipation structure 100 with a fan-fin structure 13 .

[0134] The technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification, as long as there is no contradiction in such combination. Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application, rather than to limit it; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A method for preparing a heat dissipation structure, characterized in that: The heat dissipation structure is used to dissipate heat after the IGBT chip is connected, and includes the following steps: A heat sink pre-treatment step is performed to form a blind groove of a preset depth on at least one side of the heat sink along the thickness direction to obtain a heat sink to be combined; The metallized ceramic substrate preparation process comprises pre-treating the metal sheet and the ceramic substrate, laminating and firing them to obtain a metallized ceramic substrate having a ceramic layer and a metal layer in a thickness direction; A substrate pre-treatment step is to pattern the surface of the metal layer along the thickness direction so that the ceramic layer has an exposed surface along the thickness direction, and the metal layer on the exposed surface forms a metal boss that can match the blind groove, and the surface of the metal boss is subjected to a first surface treatment to obtain a substrate to be bonded; In the integration process, the metal boss on the substrate to be combined is installed in the blind groove of the heat sink to be combined, and the exposed surface is directly attached to the surface of the heat sink to be combined to form a combination, and the combination is sintered and cured to obtain a heat dissipation structure.

2. The preparation method according to claim 1, characterized in that: The patterning process includes: The surface of the metal layer is sequentially subjected to masking, exposure and development, so that a portion of the surface of the metal layer is exposed to the mask along the thickness direction according to a preset path, and then the metal layer exposed to the mask is fully etched, so that the ceramic layer has an exposed surface along the thickness direction, and the metal layer on the exposed surface forms a metal boss that can match the blind groove; The surface of the metal boss is subjected to a mask removal process, and a substrate to be bonded is obtained after a first surface treatment.

3. The preparation method according to claim 2, characterized in that: The preparation method satisfies any one of the following conditions: (1) After the full etching process, a plurality of the metal bosses are arranged in an array on the surface of the ceramic layer, and after the mask removal process, the exposed surface of the ceramic layer is cut along the thickness direction to form a line groove, and after the first surface treatment, a splitting process is performed based on the line groove to obtain a plurality of substrates to be combined; (2) When the metal layer is aluminum and the heat sink is copper, the heat sink pre-treatment step further includes performing a second surface treatment on the surface of the blind groove; the second surface treatment includes plating nickel on the surface of the blind groove to form a nickel layer; (3) When the metal layer and the heat sink are both made of aluminum, the heat sink pre-treatment step further includes performing a second surface treatment on the surface of the blind groove; the second surface treatment includes removing the oxide layer on the surface of the blind groove and / or providing a transition film containing aluminum or aluminum alloy on the surface of the blind groove; (4) When the metal layer and the heat sink are both copper, the heat sink pre-treatment step further includes performing a second surface treatment on the surface of the blind groove; the second surface treatment includes performing an oxidation treatment on the surface of the blind groove to form a copper oxide layer; (5) When the metal layer is copper, the first surface treatment includes oxidizing the surface of the metal boss to form a copper oxide layer; (6) When the metal layer is aluminum, the first surface treatment includes removing the oxide layer on the surface of the metal boss and / or providing a transition film containing aluminum or aluminum alloy on the surface of the metal boss; (7) When the metal layer is copper, the sintering and curing treatment is performed under nitrogen protection; or when the metal layer is aluminum, the sintering and curing treatment is performed in a vacuum environment.

4. The preparation method according to claim 3, characterized in that: The oxidation treatment includes wet oxidation or dry oxidation; wherein the wet oxidation introduces oxygen elements on the copper surface through chemical reagents, and the dry oxidation forms a copper oxide layer by oxidizing the copper surface in a weak oxygen environment.

5. The preparation method according to claim 1, characterized in that: In the metallized ceramic substrate preparation process, the pretreatment includes: When the metal sheet is copper, the metal sheet is cleaned and oxidized, and the ceramic substrate is cleaned and / or surface-modified; or, When the metal sheet is aluminum, after the metal sheet and the ceramic substrate are cleaned respectively, a transition metal or non-metal film is formed on the surface of the cleaned metal sheet or the ceramic substrate.

6. The preparation method according to claim 1, characterized in that: The preparation method satisfies at least one of the following conditions: A. In the heat sink pre-treatment process, the preset depth is less than or equal to the thickness of the metal layer; B. In the heat sink pretreatment process, blind grooves of preset depth are respectively opened on both sides of the heat sink to be combined along the thickness direction, and the blind grooves on both sides of the heat sink to be combined are aligned along the thickness direction; C. In the integration process, the assembly is installed in a positioning mold for sintering and curing; D. The integration process further includes vertically symmetrically cutting the heat sink along the thickness direction based on the assembly after sintering and curing to obtain a heat dissipation structure; F. The raw material of the metal sheet is a single metal or an alloy obtained by combining multiple metals; the metal sheet includes at least one metal element selected from copper, aluminum or nickel; G. The ceramic substrate includes any one of an aluminum oxide ceramic substrate, an aluminum nitride ceramic substrate, a silicon nitride ceramic substrate or a silicon carbide ceramic substrate.

7. The preparation method according to claim 1, characterized in that: The integration process also includes opening a plurality of through holes arranged vertically at intervals along the thickness direction on the thickness surface of the heat sink based on the assembly after sintering and curing treatment, and vertically symmetrically cutting the heat sink along the thickness direction to form a fan-wing structure on the surface of the heat sink.

8. The preparation method according to claim 6, characterized in that: The positioning mold comprises a shell, the shell is formed with a receiving groove, the bottom of the receiving groove is formed with at least one supporting groove, the supporting groove is used to accommodate and support the metal boss on the side of the assembly away from the heat sink, and the receiving groove is used to accommodate the assembly and support the heat sink; Wherein, the inner surface of the shell is sprayed with inorganic isolation powder; and the shell is made of silicon carbide or silicon nitride.

9. A heat dissipation structure, characterized in that: The heat dissipation structure is prepared by the preparation method according to any one of claims 1 to 8, wherein the heat dissipation structure comprises a metallized ceramic substrate and a heat sink; The metallized ceramic substrate comprises a ceramic layer and a metal layer bonded to the surface of the ceramic layer, wherein the metal layer is used to bond and connect the IGBT chip along the thickness direction; The heat sink is directly bonded and connected to a side of the ceramic layer away from the metal layer and is integrally formed.

10. An IGBT module, characterized in that: It comprises the heat dissipation structure as claimed in claim 9, a soldering layer and an IGBT chip, wherein two sides of the soldering layer along the thickness direction are respectively connected to the IGBT chip and the metal layer surface of the heat dissipation structure.

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