Power Semiconductor Module Recess Adhesion
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Solution Overview
Problem
The existing power semiconductor modules face reliability issues due to weak adhesion between the spray coated film and the sealing resin, caused by thermal stress from the difference in thermal expansion coefficients between the conductor plate and the sealing resin, leading to potential separation of the spray coated film from the resin sealer.
Innovation Solution
A power semiconductor module design that incorporates a recess in the resin sealer, allowing for increased adhesion strength between the spray coated film and the resin sealer, by ensuring the spray coated film is securely bonded to the resin sealer, preventing separation and enhancing module reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a spray coated film is formed on the conductor plate and sealing resin, then heat dissipation capability is improved, but adhesion strength between the spray coated film and sealing resin deteriorates due to thermal stress
Solution Approach 1:
The recess is formed in the sealing resin before the spray coated film is applied. This preliminary structural preparation creates a mechanical interlocking feature that will later enhance adhesion strength when the spray coated film is deposited over the recess, resolving the contradiction between heat dissipation and adhesion.
Solution Approach 2:
The recess introduces a curved or non-planar surface geometry in the sealing resin. This curvature creates a mechanical interlock with the spray coated film, preventing separation under thermal stress while maintaining the heat dissipation function of the ceramic insulation layer.
2Ease of manufacture
If the spray coated film is applied directly on the sealing resin surface, then manufacturing process is simplified, but reliability deteriorates due to film separation under thermal stress
Solution Approach 1:
The recess structure is prepared in advance during the sealing resin formation process, before the spray coating process. This preliminary action ensures that the subsequent spray coated film application will achieve strong adhesion without requiring complex additional processing steps, thus maintaining ease of manufacture while improving reliability.
Solution Approach 2:
The recess creates a porous or cavity-containing structure in the sealing resin that enhances mechanical interlocking with the spray coated film. This structural feature improves reliability by preventing film separation while being compatible with standard manufacturing processes.
3Manufacturing precision
If a flat spray coated film is formed on the sealing resin, then manufacturing precision is maintained, but adhesion strength deteriorates due to weak bonding interface
Solution Approach 1:
The recess introduces a controlled geometric feature (curved or non-planar surface) in the sealing resin that enhances adhesion through mechanical interlocking. The spray coated film is still applied with manufacturing precision, but the recess geometry creates a stronger bonding interface that overcomes the weakness of flat surface adhesion.
Solution Approach 2:
The recess creates a localized structural feature in the sealing resin that specifically enhances adhesion at the interface with the spray coated film. The rest of the sealing resin maintains its original properties, allowing manufacturing precision to be maintained while improving adhesion strength at the critical bonding interface.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The increased adhesion strength between the spray coated film and the resin sealer improves the reliability of the power semiconductor module by preventing separation and maintaining effective heat dissipation characteristics.
Implementation Method 1
Since a ceramic insulation layer has excellent thermal conductivity, the ceramic insulation layer with a heat sink for cooling purposes layered thereon allows a power semiconductor module having an excellent heat dissipation characteristic to be manufactured at low cost.
Implementation Method 2
providing the recess in the resin sealer increases intimate adhesion strength between the spray coated film and the resin sealer and hence prevents the spray coated film from separating from the resin sealer
Data Source
AI summary
An insulation film that strongly adheres to a power semiconductor module having a resin sealer and a conductor plate and has high thermal conductivity is provided.An insulation layer 700 is provided between a power semiconductor module 302 and a heat dissipation portion 307B. The power semiconductor module 302 includes a resin sealer 348, which covers a circumferential side surface of a conductor plate 315, and a plurality of recesses 348D are provided in the resin sealer 348. The insulation layer 700 is formed of a spray coated film 710, an insulation film 720, and a resin layer 730, and the spray coated film 710 is formed on the surface of the resin sealer 348 including recesses 348D to form a seamless flat surface. The planar size of each of the recesses 348D is greater than the planar size of each flat portion 711, which forms the spray coated film 710.