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CN-121816111-B - Packaging method of high-power-density SiC power module

CN121816111BCN 121816111 BCN121816111 BCN 121816111BCN-121816111-B

Abstract

The invention discloses a packaging method of a high-power-density SiC power module, and relates to the field of semiconductor processing. The packaging method of the high-power-density SiC power module provides key components such as a power chip, a first substrate, a second substrate, a plurality of conductive columns, a heat dissipation shell and the like, and the module is assembled and packaged through specific process steps. The packaging method of the high-power density SiC power module constructs a three-dimensional power loop with low parasitic inductance, overcomes the defects of large area and high parasitic parameter of the traditional planar bonding wire packaging loop, expands a heat dissipation path, reduces module thermal resistance, enhances insulation and protection, integrally reduces parasitic inductance in a single process frame in a coordinated manner, improves heat dissipation and improves structural compactness, and provides a reliable packaging solution for realizing the high-power density and high-performance SiC power module.

Inventors

  • BI WANQING
  • LI MINGDA

Assignees

  • 北一半导体科技(广东)有限公司

Dates

Publication Date
20260512
Application Date
20260311

Claims (8)

  1. 1. A method of packaging a high power density SiC power module, the method comprising the steps of: Step S1, providing a power chip (1), a first substrate (2), a second substrate (3), a plurality of conductive columns (4) and a heat dissipation shell (5); Step S2, forming a high heat conductivity connecting layer (21) on the first substrate (2), and fixing the power chip (1) to the first substrate (2) through the high heat conductivity connecting layer (21); Step S3, electrically connecting the upper surface electrode of the power chip (1) to the second substrate (3) by using a conductive clamp; step S4, vertically interconnecting the second substrate (3) and the first substrate (2) through the conductive posts (4) so as to construct a three-dimensional power loop; Step S5, configuring the heat dissipation shell (5) to be in thermal contact with the outer sides of the first substrate (2) and the second substrate (3) respectively so as to form a double-sided heat dissipation structure; S6, filling pouring sealant in an inner space surrounded by the first substrate (2), the second substrate (3), the heat dissipation shell (5) and the power chip (1), Before the step S6, the method further comprises the step of integrating the signal patch panel (7): providing a signal patch panel (7) integrated with a driving circuit and a sensing circuit; -mounting the signal patch panel (7) to a side area of the first substrate (2) or second substrate (3); The control signal output end of the signal adapter plate (7) is connected with the control electrode of the power chip (1) in a short wire connection mode, The signal adapter plate (7) comprises a temperature sensor and/or a current sensor, and the sensing circuit is configured to: the temperature sensing point of the temperature sensor is close to the packaging area of the power chip (1); And connecting the detection end of the current sensor in series in a power loop of the power chip (1), and utilizing the temperature sensor and the current sensor to monitor and control the working state of the module in real time.
  2. 2. The method according to claim 1, wherein in the step S1, the first substrate (2) and the second substrate (3) are both directly bonded copper substrates, and the power chip (1) is a SiC chip.
  3. 3. The method according to claim 2, wherein in the step S2, the high thermal conductivity connecting layer (21) is a nano silver sintered layer, and the step of forming the nano silver sintered layer and fixing the power chip (1) to the first substrate (2) comprises: Coating nano silver paste on a preset position of the first substrate (2); Aligning the back electrode of the power chip (1) on the nano silver paste; Sintering is carried out under the preset temperature and pressure conditions to form mechanical connection and electrical conduction.
  4. 4. The method of packaging a high power density SiC power module according to claim 3, wherein in said step S3, said conductive clip is a preformed copper clip (6), and wherein said step of electrically connecting with said copper clip (6) comprises: Aligning one end of the copper clamp (6) with an upper surface electrode of the power chip (1) and crimping or welding; And aligning and welding the other end of the copper clamp (6) with a corresponding bonding pad on the lower surface of the second substrate (3).
  5. 5. The method according to claim 4, wherein in the step S4, the plurality of conductive pillars (4) are arranged in an array manner in a predetermined interconnection area between the first substrate (2) and the second substrate (3), and the step of vertically interconnecting includes: the two ends of the conductive column (4) are fixedly connected with corresponding through holes or bonding pads on the first substrate (2) and the second substrate (3) in a welding or sintering mode respectively to form a vertical current path; The arrangement positions, the number and the section sizes of the conductive posts (4) are optimally designed according to the parasitic inductance value, the current capacity and the heat dissipation requirement of the three-dimensional power loop, so that the total parasitic inductance of the module is smaller than 1nH.
  6. 6. The method of claim 5, wherein in step S5, the step of forming a double-sided heat dissipation structure comprises: Coating a heat conduction interface material on one side of the first substrate (2) far away from the power chip (1) and one side of the second substrate (3) far away from the copper clamping piece (6) respectively; The lower half part of the heat dissipation shell (5) is tightly attached to the first substrate (2) through the heat conduction interface material, the upper half part of the heat dissipation shell (5) is tightly attached to the second substrate (3) through the heat conduction interface material, and the upper heat dissipation shell (5) and the lower heat dissipation shell (5) are locked through mechanical fasteners.
  7. 7. The method for packaging a high-power-density SiC power module according to claim 1, wherein in step S6, the potting adhesive is a high-temperature silicone potting adhesive or an epoxy resin, and a step-heating curing process is performed after the potting adhesive is filled.
  8. 8. The method according to claim 1, wherein in the step S4, the conductive pillars (4) are made of copper or copper alloy, the diameter of the conductive pillars (4) is in the range of 0.5mm to 2.0mm, the height of the conductive pillars (4) is in the range of 1.0mm to 4.0mm, and the arrangement of the conductive pillars (4) is configured according to electromagnetic field simulation and thermal simulation.

Description

Packaging method of high-power-density SiC power module Technical Field The invention relates to the technical field of semiconductor processing, in particular to a packaging method of a high-power-density SiC power module. Background Silicon carbide (SiC) power modules have become a key component of the next generation high efficiency, high frequency power electronic systems by virtue of their excellent properties of the materials themselves. At present, most of mainstream commercial SiC power modules inherit on a packaging structure and adopt a mature plane packaging technology designed for a silicon-based IGBT. The technology generally employs a Direct Bond Copper (DBC) substrate as a carrier, a power die is soldered to the substrate surface by solder, and electrical interconnection of the die upper surface electrode to the substrate or other conductive sites is achieved by means of metal bond wires (e.g., aluminum wires or copper wires). The module generally conducts heat downwards to the radiator through the DBC substrate at the bottom of the chip, and the structure has the advantages of mature process and relatively controllable cost after long-term development. However, with the rapid increase of the switching speed of the SiC device and the use of the high-temperature working scenario, the conventional packaging mode based on the bonding wire and the planar layout has problems in the use process, firstly, the power loop path of the planar layout is longer and the surrounding area is large, and the parasitic inductance led by the bonding wire is matched, so that the overall parasitic inductance parameter of the module is higher, voltage overshoot and electromagnetic oscillation are easily caused in the high-frequency high-speed switching process, the switching loss is increased, the exertion of the optimal switching frequency of the SiC device is limited, meanwhile, the thermal resistance of the single-sided radiating path is larger, the heat dissipation capability and the long-term reliability of the module are unstable, the performance of the SiC chip in the high-temperature scenario cannot be fully utilized, and the two-dimensional expansion layout mode occupies more substrate area, is unfavorable for the further improvement of the power density of the module, the requirements of increasingly stringent system miniaturization and light weight are difficult to meet, and the defects of the prior art are overcome. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a packaging method of a high-power-density SiC power module, which is characterized in that a conductive column is adopted to realize vertical interconnection between a first substrate and a second substrate and is matched with a conductive clamp, so that a three-dimensional power loop with low parasitic inductance is constructed, the defects of large area and high parasitic parameter of a traditional planar bonding wire packaging loop are effectively overcome, meanwhile, a heat dissipation shell is configured to form a double-sided heat dissipation structure by respectively thermally contacting the outer sides of the first substrate and the second substrate, a heat dissipation path is expanded, the thermal resistance of the module is reduced, the filling and the filling of the inner space of the module are realized through a step process, the insulation and the protection are enhanced, the parasitic inductance is cooperatively reduced in a single process frame as a whole, the heat dissipation is improved, and the structural compactness is improved, so that a reliable packaging solution is provided for realizing the high-power-density and high-performance SiC power module. In order to achieve the above purpose, the invention is realized by the following technical scheme that the packaging method of the high-power-density SiC power module comprises the following steps: step S1, providing a power chip, a first substrate, a second substrate, a plurality of conductive columns and a heat dissipation shell; S2, forming a high-heat-conductivity connecting layer on the first substrate, and fixing the power chip on the first substrate through the high-heat-conductivity connecting layer; Step S3, electrically connecting the upper surface electrode of the power chip to the second substrate by utilizing a conductive clamp; s4, vertically interconnecting the second substrate and the first substrate through the conductive posts to construct a three-dimensional power loop; step S5, configuring the heat dissipation shell to be in thermal contact with the outer sides of the first substrate and the second substrate respectively so as to form a double-sided heat dissipation structure; and S6, filling pouring sealant in an inner space surrounded by the first substrate, the second substrate, the heat dissipation shell and the power chip. Preferably, in the step S1, the first substrate and the second substrate are both directly