Lead Frame Bonding for Press-Fit Terminal Reliability
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Solution Overview
Problem
Industrial semiconductor apparatuses for power face challenges with increased package size and manufacturing costs due to the use of cases, and existing designs are prone to damage during press-fitting and require additional components, which affect reliability.
Innovation Solution
A semiconductor apparatus with a lead frame bonded to a base plate, covered by mold resin with terminal insertion holes, allowing press-fit terminals to be inserted without damaging the mold resin or semiconductor devices, and eliminating the need for additional components like cylindrical external terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lead frame is bonded onto the semiconductor device, then the electrical connection is achieved, but the distance in the height direction between the lead pattern and the heat sink increases, causing damage such as cracks when the press-fit terminal is inserted
Solution Approach 1:
Instead of bonding the lead frame onto the semiconductor device (conventional approach), the invention inverts the bonding relationship by bonding the semiconductor device onto the lead frame. This inversion allows the lead frame to serve as the base structure that extends directly to the heat sink, reducing the height distance and preventing cracks during press-fit terminal insertion while maintaining electrical connection functionality
2Ease of operation
If a case type module is used for press-fitting, then external connection is achieved, but the package size increases and manufacturing cost increases
Solution Approach 1:
The invention merges the functions of the case and the lead frame by integrating the press-fitting structure directly into the lead frame itself. The lead frame is designed to extend outward and provide the press-fit terminal insertion capability, eliminating the need for a separate case structure. This consolidation achieves press-fitting functionality while significantly reducing package size and manufacturing cost
3Ease of operation
If a cylindrical external terminal intercommunication portion is added, then press-fit terminal insertion is enabled, but the semiconductor apparatus increases in size
Solution Approach 1:
The invention extracts the terminal insertion function from a separate cylindrical external terminal intercommunication portion and integrates it directly into the lead frame structure. The lead frame itself is configured with appropriate openings and extensions to receive and secure the press-fit terminal, eliminating the need for additional cylindrical components and reducing overall apparatus size
Data Source
AI summary
A semiconductor apparatus according to the invention of the present application includes a base plate, a lead frame having a first surface and a second surface being a surface opposite to the first surface, the second surface being bonded to an upper surface of the base plate, a semiconductor device provided on the first surface of the lead frame, and a mold resin covering the upper surface of the base plate, the lead frame, and the semiconductor device, wherein the mold resin is provided with a terminal insertion hole that extends from the surface of the mold resin to the lead frame and in which a press-fit terminal is inserted, and the lead frame is provided with an opening portion which intercommunicates with the terminal insertion hole and into which the press-fit terminal is press-fitted.