Copper busbar for multi-chip connection within an igbt module

Abstract

The utility model relates to the technical field of semiconductor, specifically relates to copper bar of multi-chip connection, and is used for the copper bar of multi-chip connection in IGBT module, including, chip connection department is connected with the upper surface electrode of multiple IGBT chips on the copper clad ceramic substrate, copper clad ceramic substrate connects the power terminal through the connection, and positioning fixed structure fixes copper bar on the copper clad ceramic substrate, and three-dimensional transition structure is connected between chip connection department, copper clad ceramic substrate connection department and positioning fixed structure, the utility model can significantly reduce the parasitic inductance of power loop, improve the dynamic current sharing performance of multi-chip, and effectively release thermal mechanical stress, thereby improve the switching performance, current-carrying capacity and reliability of module.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor technology, specifically to a copper busbar for multi-chip interconnection. Background Technology

[0002] High-power IGBT modules typically encapsulate multiple IGBT chips and diode chips internally, connecting them in parallel to increase the overall current rating. Traditional internal interconnection technology for these modules primarily uses aluminum wire bonding. However, with advancements in chip technology and the continuous increase in module current density, the limitations of aluminum wire bonding are becoming increasingly apparent: high parasitic inductance, poor current sharing capability, weak resistance to thermal fatigue, and unsuitability for future demands for higher power density and higher reliability. Utility Model Content

[0003] To address the aforementioned problems, the purpose of this invention is to provide a copper busbar for connecting multiple chips within an IGBT module.

[0004] Copper busbars used for multi-chip connections within IGBT modules, including: The chip connection part (11) is connected to the upper surface electrode of a plurality of IGBT chips located on the copper-clad ceramic substrate (2); The copper-clad ceramic substrate connection part (12) is connected to the power terminal (4) through the copper-clad ceramic substrate (2). The positioning and fixing structure (13) fixes the copper busbar on the copper-clad ceramic substrate (2); A three-dimensional transition structure (14) is connected between the chip connection part (11), the copper-clad ceramic substrate connection part (12), and the positioning and fixing structure (13).

[0005] The copper busbar for connecting multiple chips in an IGBT module according to this utility model has a three-dimensional transition structure (14) that bends and extends from both sides of the chip connection part (11) to form a "U"-shaped vertical wall structure.

[0006] The copper busbar for connecting multiple chips in an IGBT module according to the present invention comprises multiple IGBT chips (3) arranged in a matrix and connected in parallel, and the shape of the chip connection part (11) matches the planar arrangement of the multiple IGBT chips.

[0007] The copper busbar for connecting multiple chips in an IGBT module according to this utility model has a solder layer on the lower surface of the chip connection part (11), which is connected to the upper surface electrode of the IGBT chip through the solder layer.

[0008] The copper busbar for connecting multiple chips in an IGBT module described in this utility model, wherein the chip connection part (11), the copper-clad ceramic substrate connection part (12), the positioning and fixing structure (13) and the three-dimensional transition structure (14) are integrally formed structures.

[0009] The copper busbar for connecting multiple chips within an IGBT module according to this utility model has an integrally formed structure of a copper strip with a thickness of 0.3mm to 0.9mm, which is formed by bending or stamping.

[0010] The copper busbar for multi-chip connection in IGBT module described in this utility model is a platform extending upward from the three-dimensional transition structure (14) and connected to the power terminal (4) through the upper copper layer of the copper-clad ceramic substrate (2).

[0011] The copper busbar for connecting multiple chips in an IGBT module described in this utility model has a positioning and fixing structure (13) consisting of two platforms extending downward from the three-dimensional transition structure (14) and fastened to the notch in the upper copper layer of the copper-clad ceramic substrate (2).

[0012] The copper busbar for connecting multiple chips within an IGBT module as described in this utility model includes ten IGBT chips.

[0013] The copper busbar for connecting multiple chips within an IGBT module described in this utility model has a tin-silver solder layer as its solder layer.

[0014] Beneficial effects: This invention can significantly reduce the parasitic inductance of the power circuit, improve the dynamic current sharing performance of multiple chips, and effectively release thermomechanical stress, thereby improving the switching performance, current carrying capacity and reliability of the module. Attached Figure Description

[0015] Figure 1 This is a partial structural schematic diagram of the copper busbar of this utility model; Figure 2 For the present utility model Figure 1 Front view; Figure 3 This is a schematic diagram showing the usage status of the copper busbar used for connecting multiple chips within an IGBT module according to this utility model. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0019] Reference Figures 1 to 3 Copper busbars used for multi-chip connections within IGBT modules, including: The chip connection part 11 is connected to the upper surface electrode of a plurality of IGBT chips located on the copper-clad ceramic substrate 2. The copper-clad ceramic substrate connection part 12 connects to the power terminal 4 via the copper-clad ceramic substrate 2; Positioning and fixing structure 13 fixes the copper busbar onto the copper-clad ceramic substrate 2; A three-dimensional transition structure 14 connects the chip connection part 11, the copper-clad ceramic substrate connection part 12, and the positioning and fixing structure 13.

[0020] This invention can significantly reduce the parasitic inductance of the power circuit, improve the dynamic current sharing performance of multiple chips, and effectively release thermomechanical stress, thereby improving the switching performance, current carrying capacity and reliability of the module.

[0021] The three-dimensional transition structure 14 of this utility model extends from the two sides of the chip connection part 11 to form a "U"-shaped vertical wall structure.

[0022] This invention utilizes a three-dimensional "U"-shaped structure to divide and compress a traditional planar large loop into a compact three-dimensional spatial loop, significantly reducing the area enclosed by the current loop and thus lowering the parasitic inductance of the power loop, resulting in extremely low loop inductance. This helps suppress switching overvoltage, reduce switching losses, and allows for higher switching frequencies.

[0023] The present invention relates to a copper busbar for connecting multiple chips within an IGBT module. Multiple IGBT chips 3 are arranged in a matrix and connected in parallel. The shape of the chip connection part 11 matches the planar arrangement of the multiple IGBT chips.

[0024] The present invention relates to a copper busbar for connecting multiple chips within an IGBT module. A solder layer is provided on the lower surface of the chip connection part 11, and the solder layer is connected to the upper surface electrode of the IGBT chip.

[0025] The chip connection part 11, the copper-clad ceramic substrate connection part 12, the positioning and fixing structure 13 and the three-dimensional transition structure 14 of this utility model are integrally formed.

[0026] The integrated three-dimensional structure of this invention ensures that the current path from the copper-clad ceramic substrate connection part 12 to the chip connection part 11, and then to each chip, has a highly consistent geometric shape and length. This symmetry ensures a high degree of balance in the parasitic inductance of each parallel branch, thereby achieving excellent dynamic current sharing, avoiding current "competition" between chips, and improving the overall robustness and lifespan of the module.

[0027] This invention features optimized thermomechanical reliability, and the integrally formed copper busbar itself possesses excellent mechanical strength. More importantly, the three-dimensional transition structure 14, as a flexible stress relief zone, can effectively absorb and buffer stress caused by thermal expansion coefficient mismatch, preventing stress from being directly transferred to the brittle chip and significantly improving the thermal fatigue resistance of the weld joint.

[0028] The copper busbar of this utility model for connecting multiple chips in an IGBT module has a copper-clad ceramic substrate connection part 12 that is a platform extending upward from the three-dimensional transition structure 14 and is connected to the power terminal 4 through the upper copper layer of the copper-clad ceramic substrate 2.

[0029] The copper busbar of this utility model for connecting multiple chips in an IGBT module has a positioning and fixing structure 13 consisting of two platforms extending downward from the three-dimensional transition structure 14, which are fastened to the notch of the copper layer on the copper-clad ceramic substrate 2.

[0030] As an independent prefabricated component, this utility model allows for pre-applied solder as a whole. The positioning and fixing structure 13 is snapped into the copper-clad ceramic substrate 2, which effectively prevents the copper busbar from shifting during the reflow soldering process. Then, it can be soldered to multiple IGBT chips simultaneously through a single reflow soldering process, simplifying the module packaging process, facilitating automated assembly, and improving production efficiency and consistency.

[0031] One specific embodiment, referring to Figure 3The copper busbar used for multi-chip connection within the IGBT module contains ten parallel IGBT chips. The copper busbar is integrally bent or stamped from a high-conductivity copper strip with a thickness of 0.3mm to 0.9mm, preferably 0.6mm. The chip connection portion 11 consists of ten flat rectangular platforms, the lower surface of which is pre-coated with a solder layer, such as tin-silver solder. The size and position of the platform are designed to simultaneously cover and solder onto the upper surface electrodes of the ten IGBT chips 3 arranged in a rectangular array. The three-dimensional transition structure 14 is a "U"-shaped wall formed by bending vertically upward from both sides of the chip connection portion 11. This wall provides a vertical transition from the chip plane to the upper space of the module.

[0032] The copper-clad ceramic substrate connection portion 12 is a platform extending downward from the three-dimensional transition structure 14, and is connected to the power terminal 4 through the copper layer of the copper-clad ceramic substrate 2. The positioning and fixing structure 13 consists of two platforms extending downward from the three-dimensional transition structure 14, which are snapped into the notches at the copper layer of the copper-clad ceramic substrate 2 to ensure the positioning and fixing requirements of the copper busbar.

[0033] During module packaging, the copper busbar is precisely positioned onto ten IGBT chips 3 using a pre-applied solder layer, and then reflow soldered together with the copper-clad ceramic substrate 2 and the IGBT chips 3. After soldering, the chip connection portion 11 is firmly connected to the electrodes of all ten chips. Current flows out from the chip 3, converges through the chip connection portion 11 which serves as the main connection platform, flows upward through the three-dimensional transition structure 14, and finally flows to the copper-clad ceramic substrate 2 through the copper-clad ceramic substrate connection portion 12. The entire path forms a compact, low-inductance three-dimensional loop.

[0034] The description and accompanying drawings provide typical embodiments of specific structures for specific implementations. Other modifications are possible based on the spirit of this invention. Although the above-described preferred embodiments are presented, they are not intended to be limiting.

[0035] For those skilled in the art, various changes and modifications will undoubtedly be apparent after reading the above description. Therefore, the appended claims should be considered as covering all changes and modifications that encompass the true intent and scope of this utility model. Any and all equivalent scope and content within the scope of the claims should be considered as still falling within the intent and scope of this utility model.

Claims

1. A copper busbar for connecting multiple chips within an IGBT module, characterized in that, include, The chip connection part (11) is connected to the upper surface electrode of a plurality of IGBT chips located on the copper-clad ceramic substrate (2); The copper-clad ceramic substrate connection part (12) is connected to the power terminal (4) through the copper-clad ceramic substrate (2). The positioning and fixing structure (13) fixes the copper busbar on the copper-clad ceramic substrate (2); A three-dimensional transition structure (14) is connected between the chip connection part (11), the copper-clad ceramic substrate connection part (12), and the positioning and fixing structure (13).

2. The copper busbar for multi-chip connection within an IGBT module according to claim 1, characterized in that, The three-dimensional transition structure (14) bends and extends from both sides of the chip connection part (11) to form a "U" shaped vertical wall structure.

3. The copper busbar for multi-chip connection within an IGBT module according to claim 1, characterized in that, Multiple IGBT chips (3) are arranged in a matrix and connected in parallel, and the shape of the chip connection part (11) matches the planar arrangement of the multiple IGBT chips.

4. The copper busbar for multi-chip connection within an IGBT module according to claim 1, characterized in that, A solder layer is provided on the lower surface of the chip connection part (11), and the solder layer is connected to the upper surface electrode of the IGBT chip.

5. The copper busbar for multi-chip connection within an IGBT module according to claim 1, characterized in that, The chip connection part (11), the copper-clad ceramic substrate connection part (12), the positioning and fixing structure (13) and the three-dimensional transition structure (14) are integrally formed structures.

6. The copper busbar for multi-chip connection within an IGBT module according to claim 5, characterized in that, The integrally formed structure is a copper strip with a thickness of 0.3 mm to 0.9 mm, which is formed by bending or stamping.

7. The copper busbar for multi-chip connection within an IGBT module according to claim 2, characterized in that, The copper-clad ceramic substrate connection part (12) is a platform extending upward from the three-dimensional transition structure (14) and is connected to the power terminal (4) through the copper layer of the copper-clad ceramic substrate (2).

8. The copper busbar for multi-chip connection within an IGBT module according to claim 1, characterized in that, The positioning and fixing structure (13) consists of two platforms extending downward from the three-dimensional transition structure (14), which are fastened to the notch of the copper layer of the copper-clad ceramic substrate (2).

9. The copper busbar for multi-chip connection within an IGBT module according to claim 1, characterized in that, It includes ten IGBT chips.

10. The copper busbar for multi-chip connection within an IGBT module according to claim 4, characterized in that, The solder layer is a tin-silver solder layer.

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