Semiconductor Module Press-Fit Extraction Pin Bonding
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Solution Overview
Problem
Power semiconductor modules face challenges in increasing rated current and withstand voltage while maintaining a compact size, due to stress and insulation issues related to sealing materials and voids within the module, as well as difficulties in bonding external terminal pins to busbars in recessed structures.
Innovation Solution
A semiconductor module design featuring a multilayer board with a semiconductor device, extraction pins with a press-fit connection to a wiring board, and a CuSnNi alloy layer for reliable bonding, allowing for easy connection and enhanced mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a caseless/baseless structure with sealing material is used, then the module can be compact and have good insulating property, but stress from sealing material and deterioration due to voids make it difficult to increase capacity
Solution Approach 1:
The module is divided into multiple independent units, each with its own sealing and structural integrity. This allows the overall system to achieve large capacity through parallel connection while each unit maintains reliable insulation and mechanical stability.
Solution Approach 2:
The invention uses composite construction combining resin material for sealing with additional structural components (case and base) to create a hybrid structure that leverages the advantages of both materials: the resin provides insulation and stress distribution, while the case and base provide mechanical strength and void elimination.
2Reliability
If multiple small modules are connected with busbar to achieve large capacity, then current capacity increases, but long insulation distance required for high withstand voltage makes it difficult to downsize the entire module
Solution Approach 1:
Multiple semiconductor units are integrated into a single sealed module housing with shared case and base structures. The busbar connections are embedded within the sealed environment, allowing electrical connection while maintaining insulation. This merging reduces the overall size compared to separate modules while maintaining high current capacity through parallel connection of multiple units.
3Reliability
If external terminal pins are bonded to busbar in recessed structure, then connection is achieved, but difficulties in inserting soldering iron or letting laser light into recess make bonding difficult
Solution Approach 1:
The bonding surfaces are prepared in advance with appropriate materials and geometries (flat surfaces on case and base) that facilitate easy bonding operations. The external terminal pins are positioned and pre-aligned during assembly before final bonding, eliminating the need for difficult post-assembly bonding in recessed areas.
Solution Approach 2:
The case and base structures serve as intermediary bonding surfaces between the external terminal pins and the internal busbar connections. These intermediaries provide accessible, flat bonding surfaces that are easy to manufacture and bond, while still achieving the required electrical and mechanical connections to the recessed terminal pins.
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 solution enables reliable and efficient connection of extraction pins to a wiring board, improving the mechanical strength and reducing stress concentrations, thereby enabling higher rated currents and compact module designs without insulation distance limitations.
Implementation Method 1
A bonded portion between the base materials of the press-fit and the hole portion of the wiring board includes a CuSnNi alloy layer
Data Source
AI summary
Provided are a semiconductor module capable of easily connecting extraction pin with a wiring board and having reliable connections, and a method for manufacturing the same. A semiconductor module includes: a multilayer board having a semiconductor device mounted thereon, the multilayer board electrically connecting to the semiconductor device; an extraction pin electrically connecting to one of the semiconductor device and the multilayer board; and a wiring board bonded to the extraction pin for electrical connection. The extraction pin has a press-fit. The wiring board has a hole portion bonded with the press-fit of the extraction pin. The base materials of the press-fit of the extraction pin and the hole portion of the wiring board are copper (Cu). A bonded portion between the base materials of press-fit and the corresponding hole portion of the wiring board includes a CuSnNi alloy layer.