An insulating frame structure for press-fit IGBT

Abstract

The present invention provides an insulating frame structure for a press-fit IGBT, which includes an inner groove, an E-pole column, a G-pole column, a guide partition, and an umbrella skirt; the guide partition and the umbrella skirt are respectively located on the lower side and the outer side of the inner groove, and the E-pole column and the G-pole column are both vertically arranged inside the inner groove; the umbrella skirt includes at least two layers of L-shaped umbrella skirt pieces arranged in sequence. The insulating frame structure provided by the present invention is small in size, has strong versatility and stability, is easy to process, and is simple to position. It can effectively solve the insulation matching problem under different high voltage levels and meet the fixed positioning requirements of the multi-chip parallel structure inside the device. The present invention adopts modified plastic open mold injection molding, which can realize batch processing, has high electrical insulation strength, anti-creeping, and excellent mechanical properties. The glue filling port and the exhaust hole are conducive to the injection of silicone gel and the removal of air, reducing the adverse effects of local discharge caused by bubbles and thermal expansion.

Description

Technical Field

[0001] The present invention relates to the technical field of power semiconductors, and in particular to an insulating frame structure for a press-fit type IGBT. Background Art

[0002] Insulated Gate Bipolar Transistors (IGBTs) are key components for automatic control and power conversion due to their advantages, including easy drive control, high switching frequency, low on-state voltage, and high on-state current. They are widely used in converter systems with DC voltages of 600V and above, such as in rail transit, smart grids, aerospace, electric vehicles, and new energy equipment. With the continuous advancement of IGBT chip design and process technology, the continuous innovation of module packaging concepts and materials, and strong market demand, IGBT devices are developing towards higher power density, higher operating frequency, higher operating temperature, and higher reliability. In particular, in the field of flexible direct current transmission, high-voltage and high-power IGBTs have become the main development direction. Currently, in addition to silicon IGBT devices with a maximum voltage level of 6.5kV, silicon carbide devices have a withstand voltage of up to 25kV. The application of such devices in DC transmission converters will greatly reduce the number of series devices and correspondingly improve the reliability of the device.

[0003] To accommodate these series applications, high-voltage IGBTs typically utilize a press-fit package structure. This typically features parallel chips arranged in a specific pattern, with at least one side of the chip's collector (C) and emitter (E) electrodes in pressure contact with a terminal at the same potential. The two electrode terminals are parallel to each other, with the interior filled with an insulating dielectric and secured and sealed with an insulating housing. Compared to another typical package structure, the press-fit type offers lower thermal resistance, fewer parasitic parameters, and higher reliability, making it more suitable for high-voltage, high-power applications.

[0004] The ever-increasing voltage levels and current capacities not only complicate IGBT chip design and manufacturing, but also pose significant challenges to device packaging, such as the need for higher power dissipation, external chip insulation coordination, and the secure positioning of multi-chip parallel configurations. These challenges require the design of an insulating housing or frame. Typically, the insulating housing or frame is constructed of ceramic or resin composite materials. To ensure both clearance and creepage distances, structures similar to insulator ring sheds are added to the design. As voltage levels increase, clearance and creepage distances increase in accordance with regulations. To ensure device versatility, the height should be minimized while still meeting clearance requirements. However, using ring sheds in such cases makes it difficult to meet creepage distance requirements. Furthermore, as the number of high-voltage IGBT chips connected in parallel increases, press-fit chips are prone to misalignment, leading to short-circuit failure. Existing insulating frame structures using ring sheds are bulky, lack versatility and stability, are difficult to manufacture, and are complex to position. This poses insulation coordination issues for different voltage levels. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art such as large size, weak versatility and stability, difficulty in processing, complex positioning, and insulation matching problems under different high voltage levels, the present invention provides an insulation frame structure for a press-fit type IGBT, comprising an inner groove, an E-pole column, a G-pole column, a guide partition and an umbrella skirt; the guide partition and the umbrella skirt are respectively located on the lower side and the outer side of the inner groove, and the E-pole column and the G-pole column are both vertically arranged inside the inner groove; the umbrella skirt comprises at least two layers of L-shaped umbrella skirt pieces arranged in sequence, which are small in size, have strong versatility and stability, are easy to process, and are simple to position. They can effectively solve the insulation matching problems under different high voltage levels and meet the fixed positioning requirements of the multi-chip parallel structure inside the device.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0007] The present invention provides an insulating frame structure for a press-fit type IGBT, comprising an inner groove, an E-pole column, a G-pole column, a guide partition and an umbrella skirt;

[0008] The guide baffle and the umbrella skirt are respectively located at the lower side and the outer side of the inner groove, and the E-pole column and the G-pole column are both vertically arranged inside the inner groove;

[0009] The shed comprises at least two layers of L-shaped shed pieces arranged in sequence.

[0010] The number of the shed pieces increases in sequence with the increase of the voltage level.

[0011] The lengths of the L-shaped shed pieces are equal or increase in sequence from the outside to the inside.

[0012] The thickness of the L-shaped shed piece is smaller than the distance between the outer sides of adjacent L-shaped shed pieces.

[0013] The inner groove includes a partition plate at the bottom and baffles located around it;

[0014] The partition plate is provided with a glue filling port and an exhaust hole.

[0015] The glue filling port is circular or oval and is used for filling silicone gel when encapsulating IGBT chips;

[0016] The exhaust holes are provided in multiple and evenly distributed manner and are used to exhaust air when pouring silicone gel.

[0017] The depth of the inner groove is equal to the thickness of the silicone gel.

[0018] One side of the E-pole column is connected to the partition plate, and the other side thereof is at a preset distance from the IGBT chip;

[0019] A hole is provided inside the E-pole column, and the hole is a square hole. The square hole is used to place the E-pole molybdenum sheet and limit the E-pole lead-out end.

[0020] One side of the G-pole column is connected to the partition plate;

[0021] A hole is provided inside the G-pole column, and the hole limits the G-pole lead-out terminal.

[0022] The number of the E-pole columns is equal to the number of IGBT chips;

[0023] The number of the G-pole columns is at least two.

[0024] The guide partition is vertically arranged on the lower side of the partition plate and is provided with a hole;

[0025] The hole is connected to the hole of the E-pole column and the hole of the G-pole column, and is used to guide, position and isolate the E-pole lead-out terminal of the IGBT chip when the E-pole lead-out terminal is pressed into the E-pole column, and is used to guide, position and isolate the G-pole lead-out terminal of the IGBT chip when the G-pole lead-out terminal is pressed into the G-pole column.

[0026] The number of the E-pole lead-out terminals is equal to the number of the E-pole columns, and the number of the G-pole lead-out terminals is equal to the number of the G-pole columns;

[0027] The size of the holes on the guide partition matches the G-pole lead-out terminal and the E-pole lead-out terminal, and the number of the holes is the sum of the number of the E-pole lead-out terminals and the number of the G-pole lead-out terminals.

[0028] The insulating frame structure further includes a supporting groove, which is used to position and support the C-pole molybdenum plate when packaging the IGBT chip.

[0029] The size of the support groove matches the C-pole molybdenum sheet, and the C-pole molybdenum sheet is parallel to the partition plate.

[0030] A groove is provided inside the supporting groove, and the groove is filled with adhesive;

[0031] The adhesive is used to fix the C-pole molybdenum plate and the supporting groove when packaging the IGBT chip.

[0032] The insulating frame structure is made of flame-retardant resin modified plastic by injection molding, and its dimensional deviation is no more than 0.1mm;

[0033] The height of the insulating frame structure is higher than the height required for the electrical clearance of the corresponding voltage level, and the comparative tracking index is greater than or equal to 600.

[0034] Compared with the closest existing technology, the technical solution provided by the present invention has the following beneficial effects:

[0035] The insulating frame structure for a press-fit IGBT provided by the present invention includes an inner groove, an E-pole column, a G-pole column, a guide partition, and an shed. The guide partition and shed are respectively located on the lower side and the outer side of the inner groove, and the E-pole column and the G-pole column are both vertically arranged inside the inner groove. The shed includes at least two layers of L-shaped shed sheets arranged in sequence. It is compact, highly versatile and stable, easy to process, and simple to position. It can effectively solve the insulation coordination problem under different high voltage levels and meet the fixed positioning requirements of the multi-chip parallel structure inside the device.

[0036] The present invention is suitable for packaging IGBT chips at different voltage levels, especially for packaging in high-voltage environments, and can achieve support, fixation and electrical insulation of the IGBT chip and other internal and external structures;

[0037] The insulating frame structure provided in this application provides sufficient electrical clearance and creepage distance, can meet the electrical insulation coordination requirements under high voltage levels, and can be flexibly adjusted in size to meet the packaging requirements of devices of different specifications;

[0038] The present invention adopts flame retardant resin modified plastics for mold injection molding, which can realize batch processing, has high electrical insulation strength, anti-creeping and excellent mechanical properties;

[0039] During the packaging process, the present invention performs corresponding fixation or positioning for the connection of different components, including fixation of the IGBT chip and the C-pole molybdenum sheet, positioning of the E-pole molybdenum sheet and the E-pole lead-out terminal, and silicone gel potting fixation and limitation, etc., to ensure that all parts are accurately assembled and reliably connected, with simple positioning, reduced packaging difficulty, and improved packaging quality.

[0040] The shed, made up of multiple layers of L-shaped shed sheets, meets the long creepage distance requirements without significantly increasing the overall dimensions.

[0041] The glue injection port and the exhaust hole provided in the present invention are conducive to injecting silicone gel and removing air, thereby reducing the adverse effects of local discharge caused by bubbles and thermal expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 3D diagram of an insulating frame structure for a press-fit IGBT according to an embodiment of the present invention;

[0043] Figure 2 is a cross-sectional view of an insulating frame structure for a press-fit type IGBT in an embodiment of the present invention;

[0044] Figure 3 1 is a top view of an insulating frame structure for a press-fit IGBT in an embodiment of the present invention;

[0045] Figure 4 Schematic diagram of an insulating frame structure package for a press-fit IGBT in an embodiment of the present invention;

[0046] In the figure, 1-insulating frame structure, 2-support groove, 3-inner groove, 31-partition plate, 32-exhaust hole, 33-baffle, 4-E pole column, 5-G pole column, 6-umbrella skirt, 7-glue filling port, 8-guide partition, 9-C pole molybdenum plate, 10-IGBT chip, 11-E pole molybdenum sheet, 12-G pole lead end, 13-E pole lead end, 14-silicone gel. DETAILED DESCRIPTION

[0047] The present invention will be described in further detail below with reference to the accompanying drawings.

[0048] The embodiment of the present invention provides an insulating frame structure for a press-fit type IGBT, such as Figure 1-3 As shown, the insulating frame structure 1 includes an inner groove 3, an E-pole column 4, a G-pole column 5, a guide partition 8 and an umbrella skirt 6;

[0049] The guide baffle 8 and the umbrella skirt 6 are respectively located at the lower side and the outer side of the inner groove 3, and the E-pole column 4 and the G-pole column 5 are both vertically arranged inside the inner groove 3;

[0050] The shed 6 comprises at least two layers of L-shaped shed sheets arranged in sequence.

[0051] The number of shed segments increases with increasing voltage level. In this embodiment of the present invention, three layers of L-shaped shed segments are provided. The L-shaped shed segments are of equal length or increase in length from the outside to the inside. The thickness of the L-shaped shed segments is less than the spacing between the outer sides of adjacent L-shaped shed segments.

[0052] The inner groove 3 includes a partition plate 31 at the bottom and baffles 33 around the periphery;

[0053] The partition plate 31 is provided with a glue injection port 7 and an exhaust hole 32, which is conducive to injecting the silicone gel 14 and removing air, thereby reducing the adverse effects of partial discharge caused by bubbles and thermal expansion.

[0054] The glue pouring port 7 is used to pour silicone gel 14 when packaging the IGBT chip 10. It is circular or elliptical. In this embodiment, the glue pouring port 7 is elliptical. After pouring the silicone gel 14, the depth of the inner groove 3 is equal to the thickness of the silicone gel 14.

[0055] There are multiple and evenly distributed exhaust holes 32 for exhausting air when pouring silicone gel 14. In this embodiment, there are 12 exhaust holes 32 in total, 4 of which are evenly arranged in the middle position of the partition plate 31, and the remaining 8 are evenly arranged on the two long sides of the partition plate 31, that is, there are 4 exhaust holes 32 on each long side.

[0056] One side of the E-pole column 4 is connected to the partition plate 31 , and the other side thereof is at a preset distance from the IGBT chip 10 ;

[0057] The hole set inside the E-pole column 4 is a square hole, which is used to place the E-pole molybdenum sheet 11 and limit the E-pole lead-out terminal 13 to prevent the E-pole molybdenum sheet 11 from pressing against the G-pole terminal of the IGBT and causing short circuit failure.

[0058] One side of the G-pole column 5 is connected to the partition plate 31 , and a hole provided inside the G-pole column 5 limits the G-pole lead-out terminal 12 .

[0059] The number of the E-pole columns 4 , the number of the E-pole lead-out terminals 13 and the number of the IGBT chips 10 are all equal.

[0060] The number of G-pole terminals 12 is equal to the number of G-pole columns 5. There are at least two G-pole columns 5, and the embodiment of the present invention is provided with two G-pole columns. A guide baffle 8 is vertically disposed below the partition plate 31. The holes in the guide baffle 8 communicate with the holes in the E-pole columns 4 and the holes in the G-pole columns 5. The guide baffle 8 is used to guide, position, and isolate the E-pole terminals 13 of the IGBT chip 10 when they are pressed into the E-pole columns 4. It is also used to guide, position, and isolate the G-pole terminals 12 of the IGBT chip 10 when they are pressed into the G-pole columns 5.

[0061] The size of the holes provided on the guide partition 8 matches the G-pole lead-out terminal 12 and the E-pole lead-out terminal 13 , and the number of the holes provided on the guide partition 8 is the sum of the number of the E-pole lead-out terminals 13 and the number of the G-pole lead-out terminals 12 .

[0062] The insulating frame structure 1 provided in this embodiment of the present invention also includes a support groove 2, which is used to position and support the C-pole molybdenum plate 9 when packaging the IGBT chip 10. Its size matches the C-pole molybdenum sheet 9, and the C-pole molybdenum sheet 9 is parallel to the partition plate 31. A 0.5 mm groove is provided inside the support groove 2, which is filled with an adhesive. The adhesive is used to secure the C-pole molybdenum plate 9 to the support groove 2 when packaging the IGBT chip 10.

[0063] The insulating frame structure 1 is injection-molded using flame-retardant resin modified plastic, and its dimensional deviation is no more than 0.1 mm; and the height of the insulating frame structure 1 is higher than the height required for the electrical clearance of the corresponding voltage level, and the comparative tracking index CTI is greater than or equal to 600.

[0064] An example of packaging the insulating frame structure provided by the embodiment of the present invention is as follows: Figure 4 As shown, during packaging, a whole C-pole molybdenum plate 9 and a plurality of IGBT chips 10 (the number of IGBT chips is determined by the internal current, the larger the current, the more IGBT chips are required) are installed in the support groove 2, and the E-pole molybdenum sheets 11 corresponding to the number of IGBT chips 10 are placed in the E-pole column 4, the G-pole lead-out terminal 12 of the IGBT chip 10 is pressed into the G-pole column 5, and the E-pole lead-out terminal 13 is pressed into the E-pole column 4. After completing the above assembly, a certain pressure is applied to the whole, and silicone gel 14 is poured into the glue filling port 7 to realize the packaging of the press-fit type IGBT.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Ordinary technicians in the relevant field can still modify or replace the specific implementation methods of the present invention with equivalents by referring to the above embodiments. Any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are within the scope of protection of the claims of the present invention to be approved.

Claims

1. An insulating frame structure for a press-fit IGBT, characterized in that: It includes inner groove, E-pole column, G-pole column, guide partition and umbrella skirt; The guide baffle and the umbrella skirt are respectively located at the lower side and the outer side of the inner groove, and the E-pole column and the G-pole column are both vertically arranged inside the inner groove. The inner groove includes a partition plate at the bottom and baffles located around it. The shed comprises at least two layers of L-shaped shed sheets arranged in sequence; The number of the shed pieces increases in sequence with the increase of the voltage level; The lengths of the L-shaped shed pieces are equal or increase in order from the outside to the inside; One side of the E-pole column is connected to the partition plate, and the other side thereof is at a preset distance from the IGBT chip; The E-pole column is provided with a hole inside to limit the E-pole lead-out terminal; A hole is provided inside the G-pole column, and the hole limits the G-pole lead-out terminal.

2. The insulating frame structure for a press-fit IGBT according to claim 1, wherein: The thickness of the L-shaped shed piece is smaller than the spacing between adjacent L-shaped shed pieces.

3. The insulating frame structure for a press-fit type IGBT according to claim 1, wherein: The partition plate is provided with a glue filling port and an exhaust hole.

4. The insulating frame structure for a press-fit type IGBT according to claim 3, characterized in that: The glue filling port is circular or oval and is used for filling silicone gel when encapsulating the IGBT chip; The exhaust holes are provided in multiple and evenly distributed manner and are used to exhaust air when pouring silicone gel.

5. The insulating frame structure for a press-fit type IGBT according to claim 3, characterized in that: The depth of the inner groove is equal to the thickness of the silicone gel.

6. The insulating frame structure for a press-fit type IGBT according to claim 2, wherein: The hole of the E-pole column is a square hole, and the square hole is used to place the E-pole molybdenum sheet.

7. The insulating frame structure for a press-fit type IGBT according to claim 2, wherein: One side of the G-pole column is connected to the partition plate.

8. The insulating frame structure for a press-fit type IGBT according to claim 1, wherein: The number of the E-pole columns is equal to the number of IGBT chips; The number of the G-pole columns is at least two.

9. The insulating frame structure for a press-fit IGBT according to claim 2, wherein: The guide partition is vertically arranged on the lower side of the partition plate and is provided with a hole; The hole is connected to the hole of the E-pole column and the hole of the G-pole column, and is used to guide, position and isolate the E-pole lead-out terminal of the IGBT chip when the E-pole lead-out terminal is pressed into the E-pole column, and is used to guide, position and isolate the G-pole lead-out terminal of the IGBT chip when the G-pole lead-out terminal is pressed into the G-pole column.

10. The insulating frame structure for a press-fit type IGBT according to claim 9, characterized in that: The number of the E-pole lead-out terminals is equal to the number of the E-pole columns, and the number of the G-pole lead-out terminals is equal to the number of the G-pole columns; The size of the holes on the guide partition matches the G-pole lead-out terminal and the E-pole lead-out terminal, and the number of the holes is the sum of the number of the E-pole lead-out terminals and the number of the G-pole lead-out terminals.

11. The insulating frame structure for a press-fit IGBT according to claim 2, wherein: The insulating frame structure further includes a support groove, which is used to position and support the C-pole molybdenum plate when packaging the IGBT chip; The size of the support groove matches the C-pole molybdenum sheet, and the C-pole molybdenum sheet is parallel to the partition plate.

12. The insulating frame structure for a press-fit type IGBT according to claim 11, characterized in that: A groove is provided inside the supporting groove, and the groove is filled with adhesive; The adhesive is used to fix the C-pole molybdenum plate and the supporting groove when packaging the IGBT chip.

13. The insulating frame structure for a press-fit IGBT according to claim 1, wherein: The insulating frame structure is made of flame-retardant resin modified plastic by injection molding, and its dimensional deviation is no more than 0.1mm; The height of the insulating frame structure is higher than the height required for the electrical clearance of the corresponding voltage level, and the comparative tracking index is greater than or equal to 600.

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