Power module welding tool

Abstract

The invention discloses a power module welding tool, and belongs to the field of semiconductor devices. Comprising a tool body for positioning a welding material and a lining plate on a base plate, a plurality of inserting grooves are formed in the side edge, close to limiting grooves, of the tool body, limiting blocks used for abutting against the lining plate are inserted into the inserting grooves, and height limiting grooves used for limiting the edge of a welding layer from tilting are formed in the bottoms of the limiting blocks. The lining plate comprises an upper copper layer, a middle ceramic layer and a lower copper layer which are sequentially stacked. And the height of the height limiting groove is the sum of the thicknesses of the welding material, the middle ceramic layer and the lower copper layer. One side, close to the outer side of the tool main body, of the slot is longer than the opposite side of the slot, so that the limiting block can be better mounted in the slot. The limiting blocks are matched with the insertion grooves in shape so as to limit the upwarp height of the edge of the lining plate in the vertical direction. The power module welding tool provided by the invention can achieve the effect of improving the thickness consistency of the lower welding layer of the lining plate.

Description

Technical Field

[0001] The invention relates to a semiconductor device, in particular to a power module welding tool. Background Art

[0002] Modular packaging is a common packaging method for high-current power devices. Power semiconductor module packaging technology includes material selection, structural design, process design, etc. Welded power modules are a commonly used packaging structure, usually using multiple liner plates welded to a copper substrate.

[0003] Figure 1 The overall structure diagram of the existing power module welding tooling is shown below. Before welding, the welding materials and the liner are placed in the limit frame of the welding tooling. The welding tooling can limit the horizontal movement of the liner during the welding process, ensuring that the liner can be fixed on the module copper substrate within a certain position accuracy during the welding process, thereby ensuring the assemblability of subsequent processes. However, in order to ensure good contact between the finished module substrate and the heat sink, the module substrate needs to be set to a certain pre-bending arc. As a result, during the welding process, due to the effects of gravity and the viscosity of the welding material, the existing welding tooling cannot limit the vertical movement of the liner during the welding process, which will result in poor consistency in the thickness of the solder layer under the liner, affecting the long-term reliable application of the module. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a power module welding tooling which improves the consistency of the thickness of the weld layer under the liner.

[0005] Technical solution: The power module welding tooling described in the present invention includes a tooling main body for positioning the welding material and the lining plate on the substrate. The interior of the tooling main body is hollowed out to form a limiting groove for placing the welding material and the lining plate. The tooling main body is provided with a positioning piece assembled with the substrate. The side of the tooling main body close to the limiting groove is provided with a plurality of slots, and limiting blocks for pressing the lining plate are inserted into the slots. The bottom of the limiting block is provided with a height limiting groove for limiting the warping of the edge of the welding layer.

[0006] Preferably, the limit block includes a first limit block with a longer frame arranged on the tooling body near the limit groove and a second limit block with a shorter frame arranged on the tooling body near the limit groove, and a protrusion for positioning and installing welding materials and lining plates is provided at the bottom of the first limit block.

[0007] Preferably, the lining plate comprises an upper copper layer, a middle ceramic layer and a lower copper layer which are stacked in sequence.

[0008] Preferably, the height of the height-limiting groove is the sum of the thicknesses of the welding material, the middle ceramic layer and the lower copper layer.

[0009] Preferably, the limit blocks and slots correspond to each other one by one, and four of them are provided, respectively located on the four sides of the tooling body.

[0010] Preferably, the welding material is one of SnAg3Cu0.5 welding sheet, SnAg3Cu0.5 solder paste, SnSb5 welding sheet or SnSb5 solder paste, and more preferably SnAg3Cu0.5 welding sheet.

[0011] Preferably, a side of the slot close to the outer side of the tooling body is longer than the opposite side.

[0012] Preferably, the shapes of the limiting block and the slot match each other.

[0013] Preferably, the density of the limit block is ≥7g / cm 3 .

[0014] Preferably, the material of the limit block is one of tungsten-copper alloy, copper, gold or tungsten, and more preferably tungsten-copper alloy.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) by adding a vertical limit block to the main body of the welding tooling, the vertical lift height of the edge of the liner is limited, thereby improving the consistency of the thickness of the weld layer under the liner; (2) the use of the power module welding tooling is not affected by the pre-bending of the substrate, and the feasibility is strong; (3) the service life of the power module welding tooling is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall appearance of a power module welding tool in the prior art;

[0017] Figure 2 An exploded view of the welding tooling of the present invention;

[0018] Figure 3 It is an assembly drawing of the welding tooling of the present invention;

[0019] Figure 4 for Figure 3 Side view of

[0020] Figure 5 for Figure 4 A partial enlarged view of area A. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described below in conjunction with embodiments.

[0022] like Figure 2-5As shown, the power module welding tooling described in the present invention includes a tooling body 4 for positioning the welding material 2 and the lining plate 3 on the substrate 1, the interior of the tooling body 4 is hollowed out to form a limiting groove 43 for placing the welding material 2 and the lining plate 3, and the tooling body 4 is provided with four slots 42 on the four sides close to the limiting groove 43, and limiting blocks for pressing the lining plate 3 are inserted into the slots, and a limited height groove 44 is provided at the bottom of the limiting block.

[0023] The width of the stopper is wider than the slot 42 .

[0024] The limit blocks include a first limit block 45 with a longer frame arranged on the tooling body 4 near the limit groove 43 and a second limit block 46 with a shorter frame arranged on the tooling body 4 near the limit groove 43. A protrusion for positioning and installing the welding material 2 and the lining plate 3 is provided at the bottom of the first limit block 45.

[0025] The liner 3 comprises an upper copper layer 31 , a middle ceramic layer 32 and a lower copper layer 33 which are stacked in sequence.

[0026] The height of the height limiting groove 44 is the sum of the thicknesses of the welding material 2, the middle ceramic layer 32 and the lower copper layer 33, so as to limit the warping of the ceramic edge during the welding process and ensure that the thickness of the solder is uniform everywhere.

[0027] The size of the limiting groove 43 is slightly larger than the welding material 2 and the lining plate 3 to ensure that the welding material 2 and the lining plate 3 can be placed in the limiting groove 43 .

[0028] Positioning pins assembled with the base plate 1 are provided at the four corners of the tool body 4 and matched with the four mounting holes on the base plate.

[0029] The number of the limit blocks and the slots 42 correspond to each other, and their shapes match each other to limit the warping height of the edge of the lining plate 3 in the vertical direction.

[0030] The welding material 2 is SnAg3Cu0.5 welding sheet.

[0031] The length of one side of the slot 42 close to the outer side of the tool body 4 is longer than the opposite side thereof so that the limiting block 41 can be better installed therein.

[0032] The material of the substrate 1 is copper, and the material of the limit block is tungsten-copper alloy.

[0033] The use method and working principle of the power module welding tooling described in the present invention are as follows:

[0034] (1) Place the substrate 1 horizontally on the assembly operating table;

[0035] (2) placing the tool body 4 on the copper substrate 1, and fixing the tool body 4 and the copper substrate 1 together using the positioning pieces provided on the tool body 4 and the copper substrate 1;

[0036] (3) placing the welding material 2 on the substrate 1 so that it is located in the limiting groove 43 and maintaining a certain gap so that the tooling can be easily removed after the welding process is completed;

[0037] (4) placing the lining plate 3 on the welding material 2 and restricting it in the limiting groove 43 of the tooling body 1;

[0038] (5) four limit blocks are placed in the slots 42 of the tooling body 1, so that the protrusions at the bottom of the first limit block 45 can position and install the welding material 2 and the lining plate 3. Since the limit blocks have a large density, the welding material 2 and the lining plate 3 can be kept within a certain vertical position range, thereby limiting the vertical warping height of the edge of the lining plate, thereby improving the consistency of the thickness of the welding layer under the lining plate;

[0039] (6) The assembled substrate assembly (including the copper substrate 1, the welding material 2 and the lining plate 3) and the welding tool are placed in a vacuum reflow soldering furnace for welding.

Claims

1. A power module welding tool, comprising a tool body (4) for positioning a welding material (2) and a liner (3) on a substrate (1), wherein the interior of the tool body (4) is hollowed out to form a limiting groove (43) for placing the welding material (2) and the liner (3), and a positioning piece assembled with the substrate (1) is provided on the tool body (4), characterized in that: The tool body (4) is provided with a plurality of slots (42) on the side near the limiting groove (43), into which limiting blocks for pressing the lining plate (3) are inserted, and a height limiting groove (44) for limiting the edge of the welding layer from rising is provided at the bottom of the limiting block.

2. The power module welding tool according to claim 1, characterized in that: The limit block comprises a first limit block (45) with a longer frame arranged on the tool body (4) near the limit groove (43) and a second limit block (46) with a shorter frame arranged on the tool body (4) near the limit groove (43), and a protrusion for positioning and installing the welding material (2) and the lining plate (3) is provided at the bottom of the first limit block (45).

3. The power module welding tool according to claim 1, characterized in that: The lining plate (3) comprises an upper copper layer (31), a middle ceramic layer (32) and a lower copper layer (33) which are stacked in sequence.

4. The power module welding tool according to claim 3, characterized in that: The height of the height-limiting groove (44) is the sum of the thicknesses of the welding material (2), the middle ceramic layer (32) and the lower copper layer (33).

5. The power module welding tool according to claim 1, characterized in that: The limit blocks and slots (42) are each provided in four numbers and are respectively located on the four sides of the tooling body (4).

6. The power module welding tool according to claim 1, characterized in that: The welding material (2) is one of SnAg3Cu0.5 welding sheet, SnAg3Cu0.5 welding paste, SnSb5 welding sheet or SnSb5 welding paste.

7. The power module welding tool according to claim 1, characterized in that: The length of one side of the slot (42) close to the outer side of the tooling body (4) is longer than the opposite side.

8. The power module welding tool according to claim 1, characterized in that: The shapes of the limiting block and the slot (42) match each other.

9. The power module welding tool according to claim 1, characterized in that: The density of the limit block is ≥7g / cm 3 .

10. The power module welding tool according to claim 1, characterized in that: The material of the limit block is one of tungsten-copper alloy, copper, gold or tungsten.

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