Thermal shock test method for heat dissipation pins attached to DBC and AMB boards

Abstract

The invention discloses a thermal shock test method for heat dissipation pins attached to a DBC (Direct Bonding Copper) and an AMB (Advanced Manufacturing Bonding) board, which comprises the following operation steps: in the DBC board, the heat dissipation pins are directly attached to the back surface of the DBC in an enhanced reaction mode, so that the influence of welding flux can be eliminated; in the AMB board, one of the Ag pass and the Cu pass is used to directly attach the heat dissipation pin to the back surface of the AMB board, so that the heat dissipation function decline can be reduced to the greatest extent; the heat dissipation pin is integrated with the DBC and the AMB, the coefficient of thermal expansion is the same as that of warpage, and the problems of cracks and air holes in a thermal shock reliability test in the prior art can be solved. According to the thermal shock test method for the heat dissipation pins attached to the DBC and the AMB, the heat dissipation pins are directly attached to the back face of the DBC through the Eutective reaction mode of the DBC, the influence of welding flux can be eliminated, the heat dissipation pins of an AMB product are directly attached to the back face of the AMB through Ag paste or Cu paste, and the reduction of the heat dissipation function can be reduced to the maximum extent.

Description

Technical Field

[0001] The invention relates to the technical field of thermal shock testing, and in particular to a thermal shock testing method for heat dissipation pins attached to DBC and AMB boards. Background Art

[0002] The thermal shock test method is a method for conducting thermal shock reliability tests. DCB is a substrate-shaped product manufactured by directly bonding a copper plate with an oxide layer on the surface to an alumina or aluminum nitride substrate at high temperature in a reducing atmosphere. It is widely used in power electronic products. Compared with existing substrate-type products, it has the characteristics of high thermal conductivity, high current capacity, rapid heat dissipation and excellent reliability after thermal cycling. AMB refers to a product that uses a solder paste containing active metal to weld metal on a silicon nitride or aluminum nitride substrate. Compared with DCB, it has high strength and high reliability performance and is mainly used in electric vehicles, railways and new renewable energy fields. The heat dissipation pin is a pin-shaped structure that improves the heat dissipation function and is used to discharge the heat generated by the chip and expand the specific surface area of ​​the heat dissipation plate attached to the back of the DBC / AMB. The heat dissipation pin method of the heat dissipation plate is realized. At present, the heat dissipation plate processed by the mechanical heat dissipation pin is attached to the copper on the back of the DBC / AMB using a separate solder. With the continuous development of science and technology, people have higher and higher requirements for the manufacturing process of the thermal shock test method.

[0003] The existing thermal shock test method has certain drawbacks when used. At present, the way to realize the heat sink of DBC / AMB is to attach the heat sink with heat sink pins to the back of DBC / AMB using solder to improve the heat dissipation function of separate processing. When using this method, the method of preparing the heat sink separately and using solder is applied. At this time, due to the solder used to attach the DBC / AMB and the heat sink, there are problems of reduced heat dissipation capacity and complex process. The resulting relative cost is high; in addition, since the DBC / AMB substrate and the heat sink using solder have a difference in the coefficient of thermal expansion (CTE), cracks are prone to occur during the thermal shock reliability test; in addition, during the welding process, due to the difference in warpage between the heat sink and the DBC / AMB substrate, pores are easily generated between the solders, reducing the heat dissipation performance in the area where the pores are located. For this reason, we propose a thermal shock test method for attaching heat sink pins to DBC and AMB boards. Summary of the invention

[0004] Technical problem solved: In view of the shortcomings of the prior art, the present invention provides a thermal shock testing method for attaching heat dissipation pins to DBC and AMB boards. The DBC board directly attaches the heat dissipation PIN to the back of the DBC through a eutectic reaction, which can eliminate the influence of solder, while the AMB product uses Ag paste or Cu paste to directly attach the heat dissipation PIN to the back of the AMB, which can minimize the decline in heat dissipation function and effectively solve the problems in the background technology.

[0005] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is: a thermal shock test method for DBC and AMB board attached heat dissipation pins, comprising the following steps:

[0006] S1: Prepare DBC board, AMB board, heat sink pin, Ag paste, Cu paste;

[0007] S2: In the DBC board, the heat dissipation pin is directly attached to the back of the DBC through the eutectic reaction method, which can eliminate the influence of solder;

[0008] S3: In the AMB board, using one of Ag paste and Cu paste to directly attach the heat dissipation pin to the back of the AMB can minimize the degradation of the heat dissipation function;

[0009] S4: The integration of heat dissipation pin, DBC and AMB makes the thermal expansion coefficient and warpage the same, and can improve the crack and pore problems in thermal shock reliability test of existing processes;

[0010] S5: The required shape of the heat sink pin is achieved by directly attaching the heat sink pin to the back of the DBC and AMB, and the brazing fixture is designed to use one of the nitrides and carbides that do not react with the heat sink pin during the bonding process.

[0011] As a preferred technical solution of the present application, in the steps S1-S5, the copper base plate and the heat sink are deleted, the heat sink is replaced by a heat dissipation pin, and a brazing fixture is designed.

[0012] As a preferred technical solution of the present application, the nitride in the S5 step includes a structure coated with Si3N4, BN, AlN and similar materials, and the carbide includes SiC.

[0013] As a preferred technical solution of the present application, in the step S5, for the DBC board, a fixture material of nitride and carbide that does not react with the heat dissipation pin during the bonding process is used.

[0014] As a preferred technical solution of the present application, in the S5 step, for the AMB board, even if no active metal is used, there is no problem with the attachment of the heat dissipation pins. Therefore, metal materials that do not react with Ag and Cu and are resistant to high temperatures can also be used during brazing.

[0015] As a preferred technical solution of the present application, in the S1-S5 steps, the heat dissipation pin is directly attached to the back of the DBC and AMB products through the DBC and AMB processes, which greatly simplifies the process, improves the problem of reduced heat dissipation function caused by existing solder, and improves the heat dissipation efficiency by more than 15%.

[0016] As a preferred technical solution of the present application, in steps S2 and S3, the heat dissipation pins are directly attached to the back of the DBC board and the AMB board.

[0017] As a preferred technical solution of the present application, the heat dissipation pin is attached to the back of the DBC board by eutectic reaction, and the heat dissipation pin is attached to the back of the AMB board by one of Ag paste and Cu paste.

[0018] Beneficial effects: Compared with the prior art, the present invention provides a thermal shock testing method for DBC and AMB boards attached with heat dissipation pins, which has the following beneficial effects: in this thermal shock testing method for DBC and AMB boards attached with heat dissipation pins, the DBC board directly attaches the heat dissipation pin to the back of the DBC by eutectic reaction, which can eliminate the influence of solder, while the AMB product uses Ag paste or Cu paste to directly attach the heat dissipation pin to the back of the AMB, which can minimize the decline in heat dissipation function; in order to achieve the required shape of the heat dissipation pin by directly attaching the heat dissipation pin to the back of the DBC / AMB, the fixture design as shown in the figure is more important, and during the bonding process, the fixture material that prevents deformation and functional damage of the heat sink is very important. For DBC, the material of the fixture can be nitride (including structures coated with Si3N4 / BN / AlN or similar materials) or carbide (SiC, etc.) that does not react with the heat sink pin during the bonding process; for AMB products, there is no problem with the adhesion of the heat sink pin even if active metals are not used. Therefore, metal materials that do not react with Ag / Cu and are resistant to high temperatures can also be used during brazing. The entire thermal shock test method has a simple structure, is easy to operate, and has a better effect than the traditional method. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a schematic diagram of the overall structure of a thermal shock test method for DBC and AMB board attached heat dissipation pins according to the present invention.

[0020] Figure 2 It is a structural schematic diagram of a brazing fixture in a thermal shock test method for attaching heat dissipation pins to DBC and AMB boards according to the present invention. DETAILED DESCRIPTION

[0021] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0022] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] like Figure 1 , 2 As shown, a thermal shock test method for DBC and AMB board attached heat dissipation pins includes the following steps:

[0025] S1: Prepare DBC board, AMB board, heat sink pin, Ag paste, Cu paste;

[0026] S2: In the DBC board, the heat dissipation pin is directly attached to the back of the DBC through the eutectic reaction method, which can eliminate the influence of solder;

[0027] S3: In the AMB board, using one of Ag paste and Cu paste to directly attach the heat dissipation pin to the back of the AMB can minimize the degradation of the heat dissipation function;

[0028] S4: The integration of heat dissipation pin, DBC and AMB makes the thermal expansion coefficient and warpage the same, and can improve the crack and pore problems in thermal shock reliability test of existing processes;

[0029] S5: The required shape of the heat sink pin is achieved by directly attaching the heat sink pin to the back of the DBC and AMB, and the brazing fixture is designed to use one of the nitrides and carbides that do not react with the heat sink pin during the bonding process.

[0030] The DBC board directly attaches the heat dissipation PIN to the back of the DBC through eutectic reaction, which can eliminate the influence of solder, while the AMB product uses Ag paste or Cu paste to directly attach the heat dissipation PIN to the back of the AMB, which can minimize the decline in heat dissipation function.

[0031] Furthermore, in steps S1-S5, the copper base plate and the heat sink are deleted, the heat sink is replaced by a heat dissipation pin, and a brazing fixture is designed.

[0032] Furthermore, in step S5, the nitride includes a structure coated with Si3N4, BN, AlN and similar materials, and the carbide includes SiC.

[0033] Furthermore, in step S5, for the DBC board, a fixture material of nitride and carbide that does not react with the heat dissipation pin during the bonding process is used.

[0034] Furthermore, in step S5, for the AMB board, even if active metal is not used, there is no problem in the attachment of the heat dissipation pins. Therefore, metal materials that do not react with Ag and Cu and are resistant to high temperatures can also be used during brazing.

[0035] Furthermore, in steps S1-S5, the heat dissipation pin is directly attached to the back of the DBC and AMB products through the DBC and AMB processes, which greatly simplifies the process and can improve the problem of reduced heat dissipation function caused by existing solder and improve the heat dissipation efficiency by more than 15%.

[0036] Furthermore, in steps S2 and S3, the heat dissipation pins are directly attached to the back sides of the DBC board and the AMB board.

[0037] Furthermore, when the heat dissipation pin is attached to the back of the DBC board, a eutectic reaction method is adopted, and when the heat dissipation pin is attached to the back of the AMB board, a structure of Ag paste and Cu paste is adopted.

[0038] Working principle: prepare DBC board, AMB board, heat sink pin, Ag paste, and Cu paste; in the DBC board, the heat sink pin is directly attached to the back of the DBC through eutectic reaction to eliminate the influence of solder; in the AMB board, one of Ag paste and Cu paste is used to directly attach the heat sink pin to the back of the AMB to minimize the decline in heat dissipation function; the integration of the heat sink pin, DBC, and AMB makes the thermal expansion coefficient and warpage the same, and the thermal shock reliability test crack and porosity problems of the existing process can be improved; the heat sink pin is directly attached to the back of the DBC and AMB to achieve the required shape of the heat sink pin, and the brazing fixture is designed so that one of the nitrides and carbides that do not react with the heat sink pin during the bonding process can be used.

[0039] In order to achieve the required shape of the heat sink pin by directly attaching the heat sink pin to the back of the DBC / AMB, the fixture design as shown in the figure is important. During the bonding process, the fixture material is very important to prevent the heat sink from being deformed and damaged. For DBC, the fixture material can be made of nitrides (including structures coated with Si3N4 / BN / AlN or similar materials) or carbides (SiC, etc.) that do not react with the heat sink pin during the bonding process; for AMB products, there is no problem with the attachment of the heat sink pin even if active metals are not used, so metal materials that do not react with Ag / Cu and are resistant to high temperatures can also be used during brazing.

[0040] It should be noted that, in this article, relational terms such as first and second (number one, number two), etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0041] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A thermal shock test method for DBC and AMB board attached heat dissipation pins, characterized in that: The steps include: S1: Prepare DBC board, AMB board, heat sink pin, Ag paste, Cu paste; S2: In the DBC board, the heat dissipation pin is directly attached to the back of the DBC through the eutectic reaction method, which can eliminate the influence of solder; S3: In the AMB board, using one of Ag paste and Cu paste to directly attach the heat dissipation pin to the back of the AMB can minimize the degradation of the heat dissipation function; S4: The integration of heat dissipation pin, DBC and AMB makes the thermal expansion coefficient and warpage the same, and can improve the crack and pore problems in thermal shock reliability test of existing processes; S5: The required shape of the heat sink pin is achieved by directly attaching the heat sink pin to the back of the DBC and AMB, and the brazing fixture is designed to use one of the nitrides and carbides that do not react with the heat sink pin during the bonding process.

2. A thermal shock test method for DBC and AMB board attached heat dissipation pins according to claim 1, characterized in that: In the steps S1-S5, the copper base plate and the heat sink are deleted, the heat sink is replaced by a heat dissipation pin, and a brazing fixture is designed.

3. A thermal shock test method for DBC and AMB board attached heat dissipation pins according to claim 1, characterized in that: The nitride in the S5 step includes a structure coated with Si3N4, BN, AlN and similar materials, and the carbide includes SiC.

4. A thermal shock test method for DBC and AMB board attached heat dissipation pins according to claim 1, characterized in that: In the step S5, for the DBC board, a fixture material of nitride and carbide that does not react with the heat dissipation pin during the bonding process is used.

5. A thermal shock test method for DBC and AMB board attached heat dissipation pins according to claim 1, characterized in that: In the above-mentioned step S5, even if no active metal is used for the AMB board, there is no problem in the attachment of the heat dissipation pins. Therefore, a metal material that does not react with Ag and Cu and is resistant to high temperatures can be used during brazing.

6. A thermal shock test method for DBC and AMB board attached heat dissipation pins according to claim 1, characterized in that: In the S1-S5 steps, the heat dissipation pin is directly attached to the back of the DBC and AMB products through the DBC and AMB processes, which greatly simplifies the process, improves the problem of reduced heat dissipation function caused by existing solder, and improves the heat dissipation efficiency by more than 15%.

7. A thermal shock test method for DBC and AMB board attached heat dissipation pins according to claim 1, characterized in that: In the steps S2 and S3, the heat dissipation pins are directly attached to the back sides of the DBC board and the AMB board.

8. A thermal shock test method for DBC and AMB board attached heat dissipation pins according to claim 7, characterized in that: When the heat dissipation pin is attached to the back of the DBC board, a eutectic reaction method is used. When the heat dissipation pin is attached to the back of the AMB board, a structure selected from Ag paste and Cu paste is used.

Images