Sintering method and power device

Abstract

The present application provides a sintering method and a power device. The sintering method comprises: coating a connecting material on a sintering surface of a ceramic substrate / heat dissipation substrate of a power device, so as to form a connecting material layer, the connecting material layer comprising multiple independent areas, and the position of each independent area corresponding to the position of at least one chip of the power device; attaching the ceramic substrate / heat dissipation substrate coated with the connecting material layer to the heat dissipation substrate / ceramic substrate, so as to form a component to be sintered; and performing pressure sintering on the part to be sintered, so as to complete connection of the ceramic substrate and the heat dissipation substrate. By means of the present application, not only can the amount of connecting material be reduced, reducing the cost of large-area sintering, but gaps between the independent areas can also be used as volatilization channels for solvent in a drying and sintering process, thereby reducing or preventing the formation of holes and air channels in the connecting material layer during drying and sintering, and improving heat dissipation performance of a sintered connecting layer.

Description

Sintering method and power device Technical Field

[0001] The present application relates to the technical field of power device preparation, and in particular to a sintering method and a power device. Background Art

[0002] As power modules become increasingly integrated and incorporate more and more chips, the area of ​​the copper-clad ceramic substrates within them is increasing. This, in turn, increases the area required for the connection between the power module and the heat sink. For the connection between silicon carbide power modules and heat sinks, a sintering solution can improve the thermal conductivity and strength of the connection layer, effectively maximizing the performance of the silicon carbide chips.

[0003] Since sintering typically uses silver and copper pastes as bonding materials, their current prices are close to or even higher than those of precious metals, resulting in high costs. For power modules, the effective heat dissipation path is primarily located directly below the chip, while areas further away from the chip contribute less to heat dissipation. Therefore, for such large-area sintering, using a coating solution that covers the entire sintering surface results in significant consumption of bonding materials.

[0004] On the other hand, if the coating area covers the entire copper surface of the copper-clad ceramic substrate, the large area of ​​sintered silver paste and sintered copper paste is not conducive to the volatilization of the solvent during the sintering process, which is likely to cause more holes, airways, etc. and affect the heat dissipation performance of the connection layer.

[0005] Therefore, it is necessary to find a solution that can reduce the cost of large-area sintering without affecting the sintering performance.

[0006] Summary of the Invention

[0007] In view of the above-mentioned problems in the prior art, the purpose of this application is to provide a sintering method and a power device, which can reduce the cost of large-area sintering without affecting the sintering performance.

[0008] To achieve the above-mentioned and other related purposes, the present application provides a sintering method for interconnecting a ceramic substrate and a heat dissipation substrate of a power device, wherein the power device includes a plurality of chips. The sintering method comprises:

[0009] Applying a connection material on the sintered surface of the ceramic substrate / the heat dissipation substrate to form a connection material layer, wherein the connection material layer includes a plurality of independent partitions, and the position of each independent partition corresponds to the position of at least one chip of the power device;

[0010] Mounting the ceramic substrate / the heat dissipation substrate coated with the connection material and the heat dissipation substrate / the ceramic substrate to form a to-be-sintered component;

[0011] The to-be-sintered part is subjected to pressure sintering to complete the connection between the ceramic substrate and the heat dissipation substrate.

[0012] In an optional embodiment of the present application, a vertical projection of a chip corresponding to each independent partition on the connection material layer is located within each independent partition.

[0013] In an optional embodiment of the present application, a connection material is coated on the sintering surface of the ceramic substrate / the heat dissipation substrate to form a connection material layer, comprising:

[0014] forming a coating on the sintered surface of the ceramic substrate / the heat dissipation substrate;

[0015] A connection material is applied on the sintered surface of the ceramic substrate / the heat dissipation substrate with the plating layer to form a connection material layer, wherein the plating layer is a silver plating layer, a nickel plating layer, a copper plating layer or a titanium plating layer.

[0016] In an optional embodiment of the present application, a connection material is coated on the sintering surface of the ceramic substrate / the heat dissipation substrate to form a connection material layer, comprising:

[0017] The connection material is coated on the sintering surface of the ceramic substrate / the heat dissipation substrate by adopting a steel screen printing method or a dispensing coating method to form a connection material layer.

[0018] In an optional embodiment of the present application, in the step of coating a connection material on the sintering surface of the ceramic substrate / the heat dissipation substrate to form a connection material layer, the coating thickness is between 10 μm and 800 μm.

[0019] In an optional embodiment of the present application, in the step of coating a connection material on the sintering surface of the ceramic substrate / the heat dissipation substrate to form a connection material layer, the connection material is a sintered silver paste or a sintered copper paste.

[0020] In an optional embodiment of the present application, the distance between each independent partition is between 1 mm and 10 mm.

[0021] In an optional embodiment of the present application, the ceramic substrate is a copper-clad ceramic substrate encapsulated in the power module and with a sintered surface exposed, or a copper-clad ceramic substrate not encapsulated in the power module.

[0022] In an optional embodiment of the present application, the boundary of each of the independent partitions avoids the etching grooves on the inner metal layer of the ceramic substrate.

[0023] To achieve the above-mentioned and other related purposes, the present application also provides another sintering method for interconnecting between a ceramic substrate and a heat dissipation substrate of a power device, wherein the power device includes a plurality of chips. The sintering method comprises:

[0024] Applying a connection material to the sintered surfaces of the ceramic substrate and the heat dissipation substrate respectively to form a connection material layer, wherein the connection material layer includes a plurality of independent partitions, each of which corresponds to the position of at least one chip of the power device, the connection material of at least one independent partition being applied to the connection surface of the ceramic substrate, and the connection material of the other independent partitions being applied to the connection surface of the heat dissipation substrate;

[0025] Mounting the ceramic substrate coated with the connection material and the heat dissipation substrate to form a to-be-sintered component;

[0026] The to-be-sintered part is subjected to pressure sintering to complete the connection between the ceramic substrate and the heat dissipation substrate.

[0027] To achieve the above-mentioned purpose and other related purposes, the present application also provides a power device, wherein the ceramic substrate and the heat dissipation substrate of the power device are interconnected using the above-mentioned method.

[0028] The sintering method of the present application is applied to a large-area sintering process. When applying the connecting material between the connecting area between the ceramic substrate and the heat dissipation substrate of the power device, the entire connecting area is first divided into several independent areas for coating to ensure that the area corresponding to each chip of the power device has a connecting material layer to ensure effective heat transfer, and the connecting material is partially coated on the peripheral area below the chip, thereby forming a connecting material layer including multiple independent partitions on the sintering surface of the ceramic substrate and / or the heat dissipation substrate. This not only saves the amount of connecting material and reduces the cost of large-area sintering, but also the intervals between the independent partitions can also serve as solvent volatilization channels during the drying and sintering process, thereby reducing or avoiding the formation of holes and airways in the connecting material layer during drying and sintering, and improving the heat dissipation performance of the connecting layer between the ceramic substrate and the heat dissipation substrate after sintering.

[0029] In the sintering method of the present application, when a connecting material layer including multiple independent partitions is coated on the sintering surface of the ceramic substrate and / or the heat dissipation substrate, the boundaries of each independent partition avoid the etched grooves on the internal metal layer of the ceramic substrate, thereby preventing the ceramic substrate from experiencing stress concentration in the overlapping area due to the overlap of the connecting material layer and the etched grooves on the internal metal layer of the ceramic substrate, thereby preventing the ceramic in the ceramic substrate from cracking and causing insulation failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG1 is a flow chart of a sintering method in one embodiment of the present application.

[0031] FIG2 is a schematic diagram of a coating pattern of a connection material coated on a sintered surface of a ceramic substrate according to the present application.

[0032] FIG3 is a schematic diagram of another coating pattern of the connection material coated on the sintering surface of the ceramic substrate of the present application.

[0033] FIG4 is a schematic diagram of another coating pattern of the connection material coated on the sintering surface of the ceramic substrate of the present application.

[0034] FIG5 is a photograph of a copper-clad ceramic substrate coated with a connecting material layer including two independent partitions.

[0035] FIG6 is an ultrasonic scanning microscope image of the power device after sintering. DETAILED DESCRIPTION

[0036] The following describes the embodiments of the present application through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0037] It should be noted that the diagrams provided in the following embodiments are merely schematic illustrations of the basic concepts of this application. Therefore, the diagrams only show components relevant to this application and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component can be varied arbitrarily, and the component layout can be more complex. The area of ​​each independent partition is larger than the area of ​​the corresponding chip, and each independent partition is located below and around the corresponding chip.

[0038] As shown in Figure 1, the present application proposes a sintering method. The sintering method is applied to the large-area interconnection sintering process between the ceramic substrate and the heat dissipation substrate of the power device. When applying the connecting material between the connecting area between the ceramic substrate and the heat dissipation substrate of the power device, the entire connecting area is first divided into several independent areas for coating to ensure that the area corresponding to each chip of the power device has a connecting material layer to ensure effective heat transfer, and the connecting material is partially coated on the peripheral area below the chip, thereby forming a connecting material layer including multiple independent partitions on the sintering surface of the ceramic substrate and / or the heat dissipation substrate. This not only saves the amount of connecting material and reduces the cost of large-area sintering, but also the intervals between the independent partitions can also serve as a solvent volatilization channel during the drying and sintering process, thereby reducing or avoiding the formation of holes and air channels in the connecting material layer during drying and sintering, and improving the heat dissipation performance of the connecting layer after sintering.

[0039] The power device includes a power module, a heat dissipation substrate, and a connection layer that interconnects the two. The power module is an injection-molded package containing multiple chips, which contain components and connections that implement specific functions, including but not limited to silicon-based chips, silicon carbide-based chips, diodes, bonding wires, copper bridges, lead frames, ceramic substrates, sensors, molding compounds, spacers, and other components and combinations thereof.

[0040] The ceramic substrate can be an AMB (Active Metal Brazing) substrate or a DBC (Direct Bonding Copper) substrate. For example, a copper-clad ceramic substrate has copper metal layers on both sides. The copper metal layer inside the power module is used to connect to the chip and has circuits etched on it. The copper metal layer outside the power module is used to interconnect with the heat sink substrate for heat dissipation.

[0041] The heat dissipation substrate is a substrate that directly contacts the coolant and has heat dissipation capabilities. Its material can be copper or aluminum, for example. This means the heat dissipation substrate can be a copper or aluminum substrate. For example, the heat dissipation substrate can be a liquid-cooled heat sink to dissipate heat from the power module. The liquid-cooled heat sink can be a liquid-cooled heat sink with flaps or a liquid-cooled heat sink with spoilers.

[0042] FIG1 shows a process flow chart of the sintering method of the present application, comprising:

[0043] Step S110, applying a connection material on the sintering surface of the ceramic substrate / the heat dissipation substrate to form a connection material layer, wherein the connection material layer includes a plurality of independent partitions, and the position of each independent partition corresponds to the position of at least one chip of the power device;

[0044] Step S120, mounting the ceramic substrate / the heat dissipation substrate coated with the connection material and the heat dissipation substrate / the ceramic substrate to form a part to be sintered;

[0045] Step S130 , pressurizing and sintering the part to be sintered to complete the connection between the ceramic substrate and the heat dissipation substrate.

[0046] In step S110, when applying the connecting material, it can be applied on the sintered surface of the ceramic substrate, or on the sintered surface of the heat dissipation substrate, or the connecting material can be applied on the sintered surface of the ceramic substrate and the sintered surface of the heat dissipation substrate respectively and then combined to form a final connecting material layer.

[0047] For ease of description, the entire coating process will be described in detail below with reference to FIG. 2 to FIG. 4 , by coating the connection material on the sintering surface 101 of the ceramic substrate 10 .

[0048] The connection material can be applied on the sintering surface 101 of the ceramic substrate 10 by steel screen printing or dispensing to form a connection material layer 20, and the connection material layer 20 includes multiple independent partitions, and the position of each independent partition corresponds to the position of at least one chip of the power device.

[0049] The ceramic substrate 10 can be a copper-clad ceramic substrate that is encapsulated in the power module and only exposes the metal surface, or it can be a copper-clad ceramic substrate that is not encapsulated in the power module. The ceramic substrate 10 has a sintered surface 101. The sintered surface 101 refers to the metal surface of the copper-clad ceramic substrate 10 that is in direct contact with the connecting material. It can be a bare copper surface, a silver-plated surface, a nickel-plated surface, or a titanium-plated surface, or a surface plated with a combination of copper, silver, nickel, aluminum, titanium, etc. The coating can improve the oxidation resistance, corrosion resistance and sintering processability of the substrate. The coating can be implemented by chemical plating, electroplating, physical vapor deposition, etc., which is not limited here.

[0050] Taking the silver plating layer as an example, due to the chemical stability and high oxidation temperature of silver, a silver plating layer is formed on the sintering surface 101 of the ceramic substrate 10 and / or on the sintering surface 101 of the heat dissipation substrate. During the subsequent sintering process, the silver plating layer can, on the one hand, promote the diffusion connection between the sintered material and the interface, further enhancing the interface connection strength; on the other hand, the silver plating layer can also hinder the oxidation of the copper substrate during the subsequent sintering process and during the high-temperature service of the power device, further ensuring the interface connection strength and preventing the interface oxidation of the product during the sintering process and the high-temperature service process. In addition, by silver plating the ceramic substrate 10 and / or the heat dissipation substrate, after sintering, the reliability between the heat dissipation substrate and the ceramic substrate 10 can be further improved.

[0051] As an example, the thickness of the coating is between 0.05 μm and 2 μm, such as 0.05 μm, 0.1 μm, 0.3 μm, 0.5 μm, 0.7 μm, 0.9 μm, 1 μm, 1.5 μm, 2 μm, etc. For large-area sintering, the metal surface area of ​​the ceramic substrate 10, i.e., the area of ​​the sintering surface 101, is not less than 500 mm. 2 .

[0052] Before applying the connection material layer 20 on the sintered surface 101 of the ceramic substrate 10, if there are contaminants and / or oxides on the sintered surface 101, the sintered surface 101 of the ceramic substrate 10 needs to be pre-treated by cleaning, drying, and other processes to remove the contaminants and / or oxides on its surface, thereby improving the adhesion between the connection material and the sintered surface 101, increasing the connection strength between the connection material and the sintered surface 101, and increasing the reliability of the power device.

[0053] After pre-treating the sintering surface 101 of the ceramic substrate 10, a connecting material layer 20 can be applied to the sintering surface 101 of the ceramic substrate 10 by screen printing or dispensing to form a connecting material layer 20 (serving as a connecting layer). The connecting material can be, for example, a sintering silver paste or a sintering copper paste, which is a mixture of metal particles and an organic solvent.

[0054] When coating the connecting material layer 20 on the sintering surface 101 of the ceramic substrate 10, the number and shape of the independent partitions in the connecting material layer 20 can be reasonably designed according to the position of the chip in the power module to form a coating pattern similar to that shown in Figures 2-4, so that the entire connecting material layer 20 corresponding to each power module is divided into multiple independent partitions according to the position of the chip in the power module, so that the position of each independent partition corresponds to the position of at least one chip of the power device, so that the ceramic substrate 10 of each power device and the heat dissipation substrate can be sintered and interconnected through the connecting material layer 20 with multiple independent partitions. This not only saves the amount of connecting material and reduces the cost of large-area sintering, but also the intervals between the independent partitions of the connecting material layer 20 can also serve as volatilization channels for the solvent during the drying and sintering process, thereby reducing or avoiding the formation of holes and airways in the connecting material layer 20 during subsequent drying and sintering, and improving the heat dissipation performance of the connecting layer after sintering.

[0055] When applying, the coating may be performed once or multiple times. When applying multiple times, the coating direction may be the same direction each time or different directions each time.

[0056] During coating, the outer contour of the connection material layer 20 is smaller than the outer contour of the sintering surface 101 of the ceramic substrate 10 , that is, the connection material is entirely inside the metal surface of the ceramic substrate 10 without overflowing.

[0057] During coating, the coating thickness, i.e., the thickness of the connecting material layer 20, should be appropriately selected based on actual needs. It should not be too thick or too thin. Too thin a thickness can easily lead to breakage and delamination, making it difficult to form an effective connection. Too thick a thickness can make it difficult to control the thickness of the final connecting layer, the amount of solvent volatilization, and increase thermal resistance. For example, the coating thickness ranges from 10μm to 800μm, such as 10μm, 30μm, 60μm, 90μm, 120μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, and 800μm.

[0058] When forming a connecting material layer 20 comprising multiple independent partitions on the sintered surface 101 of the ceramic substrate 10, it is necessary to take into account the circuit design within the copper-clad ceramic substrate 10, that is, the etched grooves on the internal metal layer of the copper-clad ceramic substrate 10. The boundaries of each independent partition should avoid the etched grooves on the internal metal layer of the ceramic substrate 10 as much as possible. This can prevent the connection material layer 20 from overlapping with the etched grooves on the internal metal layer of the ceramic substrate 10, causing stress concentration in the overlapping area of ​​the ceramic substrate 10, thereby causing ceramic cracking and insulation failure in the ceramic substrate 10. Of course, the boundaries of each independent partition can also partially overlap with the etched grooves on the internal metal layer of the ceramic substrate 10. The overlap length is not limited here and can be defined in combination with theoretical simulation calculations or experiments, as long as it meets the functional requirements of the product.

[0059] It should be noted that the method of coating the connection material on the sintered surface of the heat dissipation substrate is the same as the method of coating the connection material on the sintered surface 101 of the ceramic substrate 10 , so it will not be described in detail here.

[0060] In step S120 and step S130, the connecting material layer 20 can be dried first, and then the ceramic substrate 10 coated with the connecting material is mounted on the heat dissipation substrate to form a sintered part; the sintered part is placed in a sintering device for sintering, so that the solvent in the connecting material is further volatilized and the metal particles undergo atomic diffusion, and finally the connecting material is mechanically connected to the heat dissipation substrate and the ceramic substrate 10 at the same time, thereby forming a reliable system connection layer between the heat dissipation substrate and the ceramic substrate 10.

[0061] The sintering parameters are as follows: the sintering temperature is between 180°C and 260°C, for example, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, and 260°C; the sintering time is between 5 min and 20 min, for example, 5 min, 10 min, 15 min, and 20 min; and the sintering pressure is between 6 MPa and 25 MPa, for example, 6 MPa, 8 MPa, 10 MPa, 12 MPa, 15 MPa, 20 MPa, and 25 MPa.

[0062] It should be noted that the sintering temperature is crucial during the sintering process. Too high a temperature can damage components within the power module (chips, bonding wires, molding compound, etc.), while too low a temperature can prevent the connection materials from forming an effective connection.

[0063] It should be noted that when the sintered part is pressurized and sintered to complete the connection between the ceramic substrate 10 and the heat dissipation substrate, a fixed target sintering pressure can be used, or the target sintering pressure can be reached by gradually increasing the pressure. After sintering is completed, the sintering pressure can be released by gradually reducing the pressure. The pressurization rate is 0.05MPa / s-1.5MPa / s, for example, 0.05MPa / s, 0.1MPa / s, 0.3MPa / s, 0.5MPa / s, 0.8MPa / s, 1.0MPa / s, 1.2MPa / s, 1.5MPa / s, and the depressurization rate is 0.05MPa / s-1.5MPa / s, for example, 0.05MPa / s, 0.1MPa / s, 0.3MPa / s, 0.5MPa / s, 0.8MPa / s, 1.0MPa / s, 1.2MPa / s, 1.5MPa / s.

[0064] The use of pressure sintering can not only enhance the density of the sintered connecting material layer 20 and the connection strength between the heat dissipation substrate and the ceramic substrate 10, but also prevent the heat dissipation substrate and the ceramic substrate 10 from warping during the sintering process, so that the sintering method of the present application can be applied to large-area reliable interconnection between the ceramic substrate 10 and the heat dissipation substrate.

[0065] During the sintering process, the sintering atmosphere is selected based on the material of the sintering surface 101 and the connecting material. For example, if the sintering surface 101 is silver-plated, nickel-plated, or titanium-plated, and the connecting material is sintered silver paste, the sintering atmosphere can be vacuum, nitrogen, or air. For example, if the sintering surface 101 is a bare copper surface or sintered copper paste, the sintering atmosphere can be vacuum or nitrogen to prevent oxidation of the bare copper surface or copper paste.

[0066] During the cooling process to room temperature after sintering, the cooling atmosphere should also be selected based on the material of the sintering surface 101 and the connecting material. For example, if the sintering surface 101 is silver-plated, nickel-plated, or titanium-plated, and the connecting material is sintered silver paste, the cooling atmosphere can be nitrogen or air. For example, if the sintering surface 101 is a bare copper surface or sintered copper paste, the sintering atmosphere can be nitrogen to prevent oxidation of the bare copper surface or copper paste.

[0067] It should be noted that, in an optional embodiment, in order to improve the sintering efficiency and sintering quality, before sintering, the to-be-sintered part may be preheated in a sintering atmosphere; then, the preheated part may be pressurized and sintered to complete the connection between the ceramic substrate 10 and the heat dissipation substrate.

[0068] It should be noted that, in addition to coating a sintered material layer on the heat dissipation substrate or the ceramic substrate 10, sintered materials can also be coated on the heat dissipation substrate or the ceramic substrate 10 separately and then combined. Specifically, a connection material can be coated on the sintering surface 101 of the ceramic substrate 10 and the heat dissipation substrate respectively to form a connection material layer 20, the connection material layer 20 includes a plurality of independent partitions, the position of each independent partition corresponds to the position of at least one chip of the power device, the connection material of at least one independent partition is coated on the connection surface of the ceramic substrate 10, and the connection material of the other independent partitions is coated on the connection surface of the heat dissipation substrate; the ceramic substrate 10 coated with the connection material and the heat dissipation substrate are mounted to form a to-be-sintered part; the to-be-sintered part is pressurized and sintered to complete the connection between the ceramic substrate 10 and the heat dissipation substrate. Taking the two rectangular independent partitions shown in FIG2 as an example, the connection material of one rectangular independent partition is coated on the connection surface of the ceramic substrate 10, and the connection material of the other independent partition is coated on the connection surface of the heat dissipation substrate.

[0069] Several specific examples of the coating scheme of this application are given below.

[0070] Example 1: Using a coating pattern similar to that shown in Figure 2, the exposed metal surface of the copper-clad ceramic substrate (AMB) on an injection-molded power module measures 40mm by 50mm. The surface is silver-plated to a thickness of 0.8μm. Sintered silver paste is applied using a stencil printing method, with two passes in opposite directions. The stencil is 600μm thick. The printed shapes are two rectangles, measuring 39mm by 14mm, spaced 10mm apart, and symmetrically centered relative to the AMB.

[0071] Example 2: Using a coating pattern similar to that shown in Figure 3, a sintered copper paste was applied to a heat sink substrate using a dot coating method. The coating thickness was 300 μm. The coating pattern was four rectangular shapes, measuring 20 mm by 18 mm, with a spacing of 5 mm in the length direction and 2 mm in the width direction. The sintered copper paste was symmetrically centered relative to the heat sink substrate. The heat sink substrate was made of copper and silver-plated to a thickness of 3 μm.

[0072] Example 3: Using a coating pattern similar to that shown in Figure 4, the copper-clad ceramic substrate (AMB) was coated directly. The exposed metal surface of the AMB was 40 mm by 50 mm and silver-plated to a thickness of 0.5 μm. Sintered silver was applied using a stencil by printing, with a single pass and a 100 μm thickness. The printed pattern consisted of multiple irregular shapes.

[0073] Taking Example 1 as an example, Figure 5 shows a photo of two rectangular independent partitions coated on a silver-plated copper-clad ceramic substrate. After coating, the surface of the sintered silver paste is smooth and there is no missing or missing print. After sintering, ultrasonic scanning inspection shows that the sintered silver paste has no defects such as delamination, cracking, and air channels. Compared with the method of coating the entire area according to the size of 39mm*49mm, the amount of connecting material used is reduced by 43%, greatly reducing the cost.

[0074] To sum up, the sintering method of the present application is applied to a large-area sintering process. When applying the connecting material between the connecting area between the ceramic substrate of the power device and the heat dissipation substrate, the entire connecting area is first divided into several independent areas for coating to ensure that there is a connecting material layer in the area corresponding to each chip of the power device to ensure effective heat transfer, and the connecting material is partially coated on the peripheral area below the chip, thereby forming a connecting material layer including multiple independent partitions on the sintering surface of the ceramic substrate and / or the heat dissipation substrate. This not only saves the amount of connecting material and reduces the cost of large-area sintering, but also the intervals between the independent partitions can also serve as solvent volatilization channels during the drying and sintering process, thereby reducing or avoiding the formation of holes and airways in the connecting material layer during drying and sintering, and improving the heat dissipation performance of the connecting layer between the ceramic substrate and the heat dissipation substrate after sintering.

[0075] In the sintering method of the present application, when a connecting material layer including multiple independent partitions is coated on the sintering surface of the ceramic substrate and / or the heat dissipation substrate, the boundaries of each independent partition avoid the etched grooves on the internal metal layer of the ceramic substrate, thereby preventing the ceramic substrate from experiencing stress concentration in the overlapping area due to the overlap of the connecting material layer and the etched grooves on the internal metal layer of the ceramic substrate, thereby preventing the ceramic in the ceramic substrate from cracking and causing insulation failure.

[0076] In the description herein, many specific details are provided, such as examples of components and / or methods, to provide a complete understanding of the embodiments of the present application. However, those skilled in the art will recognize that embodiments of the present application can be practiced without one or more specific details or by other devices, systems, assemblies, methods, components, materials, parts, etc. In other cases, well-known structures, materials, or operations are not specifically shown or described in detail to avoid blurring the aspects of the embodiments of the present application.

[0077] Reference throughout this specification to "one embodiment," "an embodiment," or "a specific embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application, and not necessarily in all embodiments. Thus, various appearances of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any specific embodiment of the present application may be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the invention described and illustrated herein are possible in light of the teachings herein and are considered part of the spirit and scope of the present application.

[0078] It should also be understood that one or more of the elements shown in the figures may also be implemented in a more separate or more integrated manner, or even removed because they are inoperable in certain circumstances or provided because they may be useful depending on the application.

[0079] In addition, unless otherwise expressly indicated, any marking arrows in the drawings should be regarded as illustrative only and not limiting. Furthermore, unless otherwise indicated, the term "or" as used herein is generally intended to mean "and / or." Where a term is unclear in providing separation or combination capabilities, the combination of components or steps will also be considered as indicated.

[0080] As used in the description herein and throughout the claims that follow, “a,” “an,” and “the” include plural references unless otherwise indicated. Likewise, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless otherwise indicated.

[0081] The above description of the embodiments shown in the present application (including the content described in the abstract of the specification) is not intended to be an exhaustive list or to limit the present application to the precise form disclosed herein. Although the specific embodiments of the present application and the examples of the present application are described herein for illustrative purposes only, as those skilled in the art will recognize and understand, various equivalent modifications are possible within the spirit and scope of the present application. As noted, these modifications can be made to the present application according to the above description of the embodiments described in the present application, and these modifications will be within the spirit and scope of the present application.

[0082] This paper generally describes the system and method as details that help to understand the application. In addition, various specific details have been given to provide an overall understanding of the embodiments of the present application. However, those skilled in the relevant art will recognize that the embodiments of the present application can be put into practice without one or more specific details, or can be put into practice using other devices, systems, accessories, methods, components, materials, parts, etc. In other cases, known structures, materials and / or operations are not particularly shown or described in detail to avoid confusion in various aspects of the embodiments of the present application.

[0083] Thus, although the present application has been described herein with reference to specific embodiments thereof, freedom of modification, various changes and substitutions are also within the foregoing disclosure, and it should be understood that in some cases, some features of the present application will be adopted without the corresponding use of other features without departing from the scope and spirit of the claimed invention. Therefore, many modifications can be made to adapt a particular environment or material to the true scope and spirit of the present application. The present application is not intended to be limited to the specific terminology used in the claims below and / or the specific embodiments disclosed as the best mode contemplated for carrying out the present application, but the present application will include any and all embodiments and equivalents falling within the scope of the appended claims. Therefore, the scope of the present application will be determined solely by the appended claims.

Claims

1. A sintering method, applied to the interconnection between a ceramic substrate and a heat dissipation substrate of a power device, wherein the power device comprises a plurality of chips, characterized in that: The sintering method comprises: Applying a connection material on the sintering surface of the ceramic substrate / the heat dissipation substrate to form a connection material layer, wherein the connection material layer includes a plurality of independent partitions, and the position of each of the independent partitions corresponds to the position of at least one chip of the power device; Mounting the ceramic substrate / the heat dissipation substrate coated with the connection material and the heat dissipation substrate / the ceramic substrate to form a to-be-sintered part; The sintered part is subjected to pressure sintering to complete the connection between the ceramic substrate and the heat dissipation substrate.

2. The sintering method according to claim 1, characterized in that: The vertical projections of the chips corresponding to the independent partitions on the connection material layer are located within the independent partitions.

3. The sintering method according to claim 1, characterized in that: Applying a connection material on the sintering surface of the ceramic substrate / the heat dissipation substrate to form a connection material layer includes: forming a coating on the sintered surface of the ceramic substrate / the heat dissipation substrate; A connection material is coated on the sintered surface of the ceramic substrate / the heat dissipation substrate on which the plating layer is formed to form a connection material layer, wherein the plating layer is a silver plating layer, a nickel plating layer, a copper plating layer or a titanium plating layer.

4. The sintering method according to claim 1, characterized in that: Applying a connection material on the sintering surface of the ceramic substrate / the heat dissipation substrate to form a connection material layer includes: The connection material is coated on the sintering surface of the ceramic substrate / the heat dissipation substrate by using a steel screen printing method or a dispensing coating method to form a connection material layer.

5. The sintering method according to claim 1, characterized in that: In the step of coating the connection material on the sintering surface of the ceramic substrate / the heat dissipation substrate to form a connection material layer, the coating thickness is between 10 μm and 800 μm.

6. The sintering method according to claim 1, characterized in that: In the step of coating a connection material on the sintering surface of the ceramic substrate / the heat dissipation substrate to form a connection material layer, the connection material is a sintered silver paste or a sintered copper paste.

7. The sintering method according to claim 1, characterized in that: The distance between each independent partition is between 1mm-10mm.

8. The sintering method according to claim 1, characterized in that: The ceramic substrate is a copper-clad ceramic substrate that is packaged in the power module and has a sintered surface exposed, or a copper-clad ceramic substrate that is not packaged in the power module.

9. The sintering method according to any one of claims 1 to 8, characterized in that: The boundary of each independent partition avoids the etching groove on the inner metal layer of the ceramic substrate.

10. A sintering method, applied to the interconnection between a ceramic substrate and a heat dissipation substrate of a power device, wherein the power device comprises a plurality of chips, characterized in that: The sintering method comprises: Coating a connection material on the sintered surfaces of the ceramic substrate and the heat dissipation substrate respectively to form a connection material layer, wherein the connection material layer includes a plurality of independent partitions, and the position of each independent partition corresponds to the position of at least one chip of the power device, and the connection material of at least one independent partition is coated on the connection surface of the ceramic substrate, and the connection materials of other independent partitions are coated on the connection surface of the heat dissipation substrate; Mounting the ceramic substrate coated with the connection material and the heat dissipation substrate to form a to-be-sintered component; The sintered part is subjected to pressure sintering to complete the connection between the ceramic substrate and the heat dissipation substrate.

11. A power device, characterized in that: The ceramic substrate and the heat dissipation substrate of the power device are interconnected by using the method described in any one of claims 1-10.

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