IGBT module power terminal welding positioning assembly and method

Abstract

The present invention discloses an IGBT module power terminal welding positioning assembly and method in the field of IGBT preparation technology, including a terminal position limiter, the terminal position limiter is fixedly placed on a DBC limiter plate, and the terminal position limiter surface is provided with a plurality of hollowed-out grooves for inserting and positioning power terminal groups with welding pieces, and a terminal spacing limiter is provided between the power terminal groups with welding pieces so that the two are kept perpendicular to the terminal position limiter, the DBC limiter plate is placed on a substrate, and the DBC and DBC welding pieces are placed in the DBC limiter plate. The present invention can ensure the reliability of the product and improve the consistency of module terminal welding.

Description

Technical Field

[0001] The invention relates to an IGBT module power terminal welding positioning component and method, belonging to the technical field of IGBT preparation. Background Art

[0002] Insulated Gate Bipolar Transistor (IGBT) is the most advanced power semiconductor device among the third generation power electronic devices. It has the advantages of high frequency, high voltage, and high current. It is a core device in the fields of flexible AC / DC power transmission, new energy generation, and power quality management. It has been widely used in related industries. In IGBT module packaging, the welding of the chip and the direct bonding copper (DBC) liner is usually called primary welding; the welding of the liner subunit composed of the chip and the DBC liner and the copper or composite material substrate is called secondary welding. Primary welding and secondary welding are key processes that affect the quality of module packaging.

[0003] At present, solder paste is usually used for soldering of high-power IGBT module terminals. Whether the terminals are soldered by manual electric soldering iron or solder paste is applied to the bottom of the terminals before soldering, a large amount of flux will be present. The residual flux after welding cleaning will reduce the reliability of the module. For high-reliability high-power IGBT modules, a large amount of flux will remain on the surface of the components and the inner wall of the welding equipment after welding. It is difficult for the cleaning equipment to completely clean the flux on the components. The residual flux will directly affect the long-term reliability of the product. Sheet-shaped solder (solder sheet) will not have flux. After welding, it does not need to be cleaned. On the one hand, it can reduce the cleaning process. On the other hand, it will not pollute the welding cavity after welding, and there will be no flux residue in the welded products, which will not affect the reliability of the product. In addition, the use of electric soldering iron welding or coating of solder paste will cause the amount of solder at the bottom of each module terminal to be different, and it is difficult to ensure the consistency of module terminal welding. The use of solder sheet to wrap the bottom of the terminal before welding can ensure the stability and consistency of the amount of solder at the bottom of the terminal.

[0004] However, when soldering the terminals with solder lugs, there is no adhesion between the terminals, solder lug materials, DBC and substrate. The relative positions are easily changed during the assembly process, resulting in welding failure. The welding quality and welding consistency cannot be guaranteed. Therefore, the method of wrapping the bottom of the terminal with solder lugs and then fixing the terminal with a device is of great significance for ensuring product reliability and improving the consistency of terminal welding. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide an IGBT module power terminal welding positioning assembly and method, which can achieve the effect of ensuring product reliability and improving the consistency of module terminal welding.

[0006] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0007] In the first aspect, the present invention provides an IGBT module power terminal welding positioning assembly, including a terminal position limiter, wherein the terminal position limiter is fixedly placed on a DBC limiter plate, and a plurality of hollow grooves for inserting and positioning power terminal groups with welding tabs are provided on the surface of the terminal position limiter, and a terminal spacing limiter is provided between the power terminal groups with welding tabs so that the two remain perpendicular to the terminal position limiter, the DBC limiter plate is placed on a substrate, and a DBC and a DBC welding tab are placed in the DBC limiter plate.

[0008] Furthermore, two terminal grooves are symmetrically provided on both sides of the hollowed-out groove, and vertical strip protrusions are provided on both edges of the terminal spacing limiter, and the thickness of the vertical strip protrusions matches the depth of the terminal grooves.

[0009] Furthermore, a plurality of positioning holes are provided on the surface of the DBC limiting plate, and the terminal position limiter is fixed in the positioning hole by a positioning pin.

[0010] Furthermore, a round hole is provided on the top of the terminal spacing limiter.

[0011] Furthermore, the dimensions of the terminal spacing limit and the terminal position limit can be customized according to the spacing requirements of the power terminals.

[0012] Furthermore, the number of the hollowed-out grooves is three, and the three hollowed-out grooves are arranged equidistantly and symmetrically on the terminal position limiting surface.

[0013] Furthermore, the power terminal group with welding tabs includes two power terminals with welding tabs, the power terminal group with welding tabs includes a power terminal whose bottom wraps around the bottom of the terminal welding tab, and the width of the terminal welding tab is less than 0.5 mm of the power terminal width.

[0014] In a second aspect, the present invention provides a method for welding and positioning power terminals of an IGBT module, comprising:

[0015] Place the DBC limit plate on the base plate;

[0016] Based on the placement position of the DBC limit plate, place the DBC welding piece and DBC in the DBC limit plate in sequence;

[0017] Fix the terminal position limiter to the corresponding positioning hole on the DBC limiter plate through the positioning pin;

[0018] According to the direction of the terminal position limit, place the power terminal group with welding piece into the hollowed-out groove of the terminal position limit;

[0019] Place the terminal spacing stop between the two power terminals with solder tabs in each cutout.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention can fix the welding piece and DBC in the area where the substrate is welded, and fix the terminal in the corresponding position on the DBC. The present invention reduces the cleaning process after welding, simplifies the production process, improves the production efficiency, and also avoids the risk caused by the unclean cleaning of the soldering flux. Terminal position limits and terminal spacing limits of different sizes can be designed according to the terminal size, welding position and the gap between the terminals. DBC limit plate tooling of different sizes can be designed according to substrates and DBCs of different sizes to achieve welding of products of different sizes. The present invention is suitable for mass production of products. The solder piece prefabrication and terminal welding device provide a standardized process flow. The solder layer of the DBC and the substrate and the solder layer of the terminal and the DBC are uniform, which improves the reliability of the product, avoids the contamination of the soldering flux to the equipment, and improves the life of the welding equipment and the stability of the product welding. During operation, only a terminal wrapped with a uniform prefabricated solder piece is needed, and the terminal is fixed by the terminal welding device when welding the terminal, so as to ensure the consistency of the terminal welding, reduce the scrap caused by human factors, and have higher stability, and improve the quality and reliability of the module. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of a terminal with a bottom-wrapped solder piece provided in an embodiment of the present invention;

[0023] Figure 2 A schematic diagram of terminal position limiting provided by an embodiment of the present invention;

[0024] Figure 3 A schematic diagram of the terminal spacing limit provided in an embodiment of the present invention;

[0025] Figure 4 A schematic diagram of a substrate provided in an embodiment of the present invention after a DBC soldering sheet, a DBC and a DBC limiting plate are placed on the substrate;

[0026] Figure 5 The embodiment of the present invention provides Figure 4 Schematic diagram after placing the terminal position limit on the basis;

[0027] Figure 6 The embodiment of the present invention provides Figure 5 Schematic diagram after placing power terminals and terminal spacing limits on the basis;

[0028] Figure 7 An exploded schematic diagram of an overall assembly provided in an embodiment of the present invention.

[0029] In the figure: 1. Power terminal; 2. Terminal soldering piece; 3. Terminal spacing limit; 4. Power terminal with soldering piece; 5. Terminal position limit; 6. DBC limit plate; 7. DBC; 8. DBC soldering piece; 9. Substrate. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0031] Example:

[0032] An IGBT module power terminal welding positioning component, such as Figure 1 As shown, the power terminal 1 with the terminal welding piece 2 wrapped at the bottom is combined into a power terminal 4 with welding piece, which can be prepared in advance as the raw materials for the welding process. The width of the terminal welding piece 2 can be adjusted according to the width of the bottom of the power terminal 1. The width of the terminal welding piece 2 should be slightly smaller than the width of the power terminal 1, generally about 0.5mm smaller than the width of the power terminal 1, and the length is preferably enough to wrap around the bottom of the terminal.

[0033] like Figure 2 As shown, the terminal spacing limiter 3 is used to ensure the gap between the two power terminals 1 and the verticality of the power terminals 1 after welding. The thickness of this device can ensure the minimum gap between the two power terminals 1, reducing the inconsistency of the power terminals 1 after welding caused by manual assembly. In addition, a round hole is made on the top of this device for easy removal, which improves the efficiency of assembly.

[0034] like Figure 3 As shown, the terminal position limit 5 is used to fix the position of the power terminal 1; this device is fixed to the positioning hole reserved on the DBC limit plate 6 by a positioning pin, and the three hollowed-out grooves on the surface are used to determine the relative position of the power terminal 1, ensuring that the position of the power terminal 1 on the DBC is relatively fixed after each welding is completed. It should be noted that two terminal grooves are symmetrically opened on both sides of the hollowed-out groove on the terminal position limit 5, and vertical strip protrusions are provided on both edges of the terminal spacing limit 3, and the thickness of the vertical strip protrusions here matches the depth of the terminal groove. When the terminal spacing limit 3 is inserted into the hollowed-out groove on the terminal position limit 5, the two power terminals 1 are respectively located on both sides of the terminal spacing limit 3, and at the same time are located in the two asymmetrical terminal grooves on both sides of the hollowed-out groove, and the other two terminal grooves without the power terminals 1 are offset against the vertical strip protrusions, thereby ensuring the overall stability between the terminal position limit 5 and the terminal spacing limit 3.

[0035] The specific implementation method is as follows: Figure 4 As shown, first place the DBC limit plate 6 on the substrate 9, and place the DBC welding piece 8 and DBC 7 according to the position of the DBC limit plate 6. Figure 5 As shown, the terminal position limiter 5 is then fixed to the corresponding positioning hole on the DBC limiter plate 6 through its positioning pin, so as to ensure that the position of the power terminal on the DBC is relatively fixed after welding. Figure 6 As shown, then according to the direction of the terminal position limiter 5, the power terminal 4 with the welding piece is placed in the hollowed-out groove of the terminal position limiter 5, and finally the terminal spacing limiter 3 is placed between the two power terminals 1 to ensure the positioning and fixation during the assembly and welding process. Figure 7 As shown, after assembling according to the above steps, the whole is placed in a vacuum welding furnace for welding. After the welding is completed and the IGBT module and the welding device are cooled, the terminal spacing limiter 3, the terminal position limiter 5 and the DBC limiter plate 6 are taken out in sequence. In addition, the terminal spacing limiter 3 and the terminal position limiter 5 can be flexibly modified in size according to the design requirements of the spacing between the two power terminals 1 of the module, avoiding the inapplicability of this method due to changes in the module design.

[0036] The present invention provides a method for improving the terminal welding consistency of a high-power IGBT module, which not only ensures the consistency of the solder amount at the bottom of the power terminal, but also ensures the consistency of the welding position of the power terminal in the module, reduces the scrap rate of module welding, and improves product quality and reliability. The method can be used for both manual placement operations and machine recognition placement operations, can be adapted to automated production lines, reduces interference from human factors, and improves the consistency and reliability of the module.

[0037] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An IGBT module power terminal welding positioning assembly, characterized in that: It includes a terminal position limiter, the terminal position limiter is fixedly placed on a DBC limiter plate, and the terminal position limiter surface is provided with a plurality of hollowed-out grooves for inserting and positioning a power terminal group with welding tabs, the power terminal group with welding tabs includes two power terminals with welding tabs, the power terminal group with welding tabs includes a power terminal whose bottom wraps around the bottom of the terminal welding tab, and the width of the terminal welding tab is less than 0.5mm of the power terminal width; a terminal spacing limiter is provided between the two power terminals with welding tabs to keep the two terminals perpendicular to the terminal position limiter, the DBC limiter plate is placed on a substrate, and the DBC and DBC welding tabs are placed in the DBC limiter plate; Two terminal grooves are symmetrically provided on both sides of the hollowed-out groove, and vertical strip protrusions are provided on both edges of the terminal spacing limiter, and the thickness of the vertical strip protrusions matches the depth of the terminal grooves.

2. The IGBT module power terminal welding positioning assembly according to claim 1, characterized in that: A plurality of positioning holes are provided on the surface of the DBC limiting plate, and the terminal position limiter is fixed in the positioning hole by a positioning pin.

3. The IGBT module power terminal welding positioning assembly according to claim 1, characterized in that: A round hole is provided on the top of the terminal spacing limiter.

4. The IGBT module power terminal welding positioning assembly according to claim 1, characterized in that: The dimensions of the terminal spacing limit and the terminal position limit are customized according to the spacing requirements of the power terminals.

5. The IGBT module power terminal welding positioning assembly according to claim 1, characterized in that: The number of the hollowed-out grooves is three, and the three hollowed-out grooves are located on the terminal position limiting surface and are symmetrically arranged with equal distances.

6. A method for welding and positioning power terminals of an IGBT module, characterized in that: include: Place the DBC limit plate on the base plate; Based on the placement position of the DBC limit plate, place the DBC welding piece and DBC in the DBC limit plate in sequence; Fix the terminal position limiter to the corresponding positioning hole on the DBC limiter plate through the positioning pin; According to the direction of the terminal position limit, place the power terminal group with welding piece into the hollowed-out groove of the terminal position limit; Place the terminal spacing stop between the two power terminals with solder tabs in each cutout.

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