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CN-118899287-B - High-voltage power device structure based on flexible interconnection, preparation method and power equipment

CN118899287BCN 118899287 BCN118899287 BCN 118899287BCN-118899287-B

Abstract

The invention discloses a high-voltage power device structure based on flexible interconnection, a preparation method and power equipment, and belongs to the technical field of power semiconductor packaging. The high-voltage power device interconnection structure based on flexible interconnection is of a double-sided packaging structure, the inherent limitations of rigid structure in double-sided interconnection packaging in the prior art are overcome through fusion of the conductive elastic pieces of the middle deformation section and the two fixed sections, the rigid multi-chip interconnection structure in the prior art is converted into a flexible structure, flexible connection of a fixed copper plate and a movable copper plate is achieved, the height difference change caused by processing tolerance of chips, welding layers, metal cushion blocks and the like is compensated through the conductive elastic pieces based on flexible connection, the influence of the upper surface height difference on welding quality during multi-chip interconnection is avoided, and meanwhile through the structural design of the high-voltage power device based on flexible interconnection, the current flowing capacity, the reliability and the thermal stress aging resistance of the high-voltage power device are improved.

Inventors

  • WANG LAILI
  • MA DINGKUN
  • SUN PEIYUAN
  • YUAN TIANSHU
  • LI LEI
  • Ding Peiyang
  • GUO JIACHENG

Assignees

  • 西安交通大学

Dates

Publication Date
20260508
Application Date
20240806

Claims (9)

  1. 1. The high-voltage power device structure based on flexible interconnection is characterized by comprising a silver column (1), a movable copper plate (2), a fixed copper plate (3), a supporting copper column (4), a power terminal (5), a conductive elastic sheet (6), a ceramic substrate (7) and a power semiconductor chip (8); The conductive elastic sheet (6) comprises a deformation section in the middle and fixing sections at two ends, wherein a fixing copper plate (3) is arranged below the fixing section, a power terminal (5) is arranged on the fixing copper plate (3), the power terminal (5) is used for realizing electric connection between a high-voltage power device and an external circuit, a supporting copper column (4) is fixed below the fixing copper plate (3), the lower surface of the supporting copper column (4) is completely attached and fixed on a ceramic substrate (7), the lower part of the deformation section is sequentially fixed on the ceramic substrate (7) through a movable copper plate (2), a silver column (1) and a power semiconductor chip (8), and the deformation section is used for compensating the height difference between the upper surfaces of the interconnection Shi Yinzhu of the power semiconductor chip (8); The silver column (1) is consistent with the supporting copper column (4) in height, the movable copper plate (2) is consistent with the fixed copper plate (3) in height, the deformation section in the middle of the conductive elastic sheet (6) is a convex ripple with an interval, and the interval is consistent with the fixed section of the conductive elastic sheet (6) in height.
  2. 2. A high voltage power device structure based on flexible interconnection according to claim 1, characterized in that the conductive dome (6) is made of spring steel material.
  3. 3. The high-voltage power device structure based on flexible interconnection according to claim 1, wherein the thickness of the conductive spring sheet (6) is 0.2 mm-0.5 mm.
  4. 4. The high-voltage power device structure based on flexible interconnection according to claim 1, wherein the heights of the silver pillars (1) and the supporting copper pillars (4) are 3 mm-5 mm.
  5. 5. The high-voltage power device structure based on flexible interconnection according to claim 1, wherein the thickness of the movable copper plate (2) and the fixed copper plate (3) is 0.5 mm-1 mm.
  6. 6. The method for manufacturing the high-voltage power device structure based on flexible interconnection according to any one of claims 1 to 5, comprising the following steps: The method comprises the steps of firstly, adopting a computer to digitally control precision machining for machining an integrated structure of a fixed copper plate (3), a supporting copper column (4) and a power terminal (5), leveling the supporting copper column (4) to ensure that the heights of the lower surfaces of the supporting copper column (4) are consistent, and fixedly connecting the supporting copper column (4) to a ceramic substrate (7); step two, fixedly connecting the fixed copper plate (3) below a fixed section of the conductive elastic sheet (6), fixedly connecting the movable copper plate (2) below a deformation section of the conductive elastic sheet (6), and realizing flexible connection of the fixed copper plate (3) and the movable copper plate (2) through the conductive elastic sheet (6); and thirdly, fixedly connecting the lower surface of the movable copper plate (2) to the upper surface of the silver column (1), fixedly connecting the lower surface of the silver column (1) to the upper surface of the power semiconductor chip (8), and fixedly connecting the lower surface of the power semiconductor chip (8) to the ceramic substrate (7).
  7. 7. The method for manufacturing the high-voltage power device structure based on the flexible interconnection, which is disclosed by claim 6, is characterized in that the fixed copper plate (3) is fixedly connected below a fixed section of the conductive elastic sheet (6) in a laser welding mode, and the lower part of a deformation section of the conductive elastic sheet (6) is fixedly connected with the movable copper plate (2) in a laser welding mode.
  8. 8. The method for manufacturing a high voltage power device structure based on flexible interconnection according to claim 6, wherein the supporting copper pillars (4) are fixedly welded to the ceramic substrate (7) by tin-based bonding pads.
  9. 9. An electrical device characterized by comprising a high voltage power device structure based on flexible interconnection according to any one of claims 1-5.

Description

High-voltage power device structure based on flexible interconnection, preparation method and power equipment Technical Field The invention relates to the technical field of power semiconductor packaging, in particular to a high-voltage power device structure based on flexible interconnection, a preparation method and power equipment. Background With the rapid leap of power electronics technology, there is an increasing need for power conversion systems with high power density, excellent efficiency and constantly reliable reliability. Silicon carbide (SiC), a bright star as a third generation semiconductor material, is gradually becoming a core force for promoting the revolution by virtue of its excellent physical and chemical properties. Under the extreme working condition of high voltage and high frequency, the parallel connection technology of the silicon carbide power chip is like a strong east wind, the current carrying capacity of the module is greatly improved, and the severe requirements of high-power conversion and transmission are accurately met. The technology not only endows the system with unprecedented flexibility, but also builds an irrevocable defense line for the reliability and usability of the system through a built-in redundancy design. High voltage high frequency power devices, particularly advanced materials devices represented by silicon carbide, are gradually exhibiting immeasurable application potential in a plurality of key fields of industrial manufacturing, energy conversion, transportation, etc., due to their excellent voltage resistance, low on-state loss, excellent heat resistance and heat conduction efficiency, and remarkable switching speed. In the application scenario of pursuing high power output, the multi-chip parallel current spreading technology of the silicon carbide power module is particularly important, and the traditional packaging interconnection structure is worry about coping with the requirement, and is mainly limited by the challenges of limited current carrying capacity and insulating performance, high-precision processing requirements and tolerance compensation problems. Conventional packaging schemes, whether of single-sided or double-sided design, have significant limitations. Although the single-sided structure is concise, the bonding wires are relied on to realize electric connection, so that the capacity of current transmission is limited, and design complexity and operation risk are increased due to the existence of parasitic inductance and the defect of insulating property. The double-sided structure comprises two ceramic substrates, a power semiconductor chip is welded on a lower ceramic substrate, a metal cushion block is welded on the upper surface of the chip, and then the upper ceramic substrate is welded with the upper surface of the metal cushion block. However, in the existing double-sided interconnection structure, since the upper and lower ceramic substrates are rigid structures, it is difficult to compensate for height differences caused by machining tolerances of chips, welding layers, metal cushion blocks and the like, so that parallel packaging of a plurality of chips is difficult to realize, and meanwhile, in the running process of a device, the chips generate heat to generate thermal expansion, and the rigid connection structure cannot release thermal stress caused by chip temperature rise. Therefore, how to provide a dual-sided packaging structure of a high-voltage power device based on flexible interconnection, to improve the current capacity and reliability of the high-voltage power semiconductor device, has become a technical problem to be overcome by those skilled in the art. Disclosure of Invention The invention aims to provide a high-voltage power device structure based on flexible interconnection, a preparation method and power equipment, which are used for overcoming the inherent limitation of a rigid structure in double-sided interconnection packaging in the prior art, and solving the problems that the height difference change caused by processing tolerances of a chip, a welding layer, a metal cushion block and the like is difficult to compensate and the thermal stress generated in the working process of the chip is effectively relieved. The invention solves the technical problems by the following technical proposal: a high-voltage power device structure based on flexible interconnection comprises silver columns, movable copper plates, fixed copper plates, supporting copper columns, power terminals, conductive spring plates, ceramic substrates and power semiconductor chips; the conductive elastic sheet comprises a deformation section in the middle and fixing sections at two ends, wherein a fixing copper plate is arranged below the fixing sections, a power terminal is arranged on the fixing copper plate and used for realizing electric connection between a high-voltage power device and an external circuit, a supporting copper