IGBT Extraction Electrode Design for Heat Cycle Life
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Solution Overview
Problem
The reduction in size of IGBT chips, combined with the limitations of aluminum wire connections, restricts chip size and impairs heat dissipation, making it difficult to meet high heat cycle life requirements in inverter circuits.
Innovation Solution
A semiconductor device design featuring power semiconductor elements with divided connection electrodes and extraction electrodes that eliminate the need for aluminum wires, allowing for independent electrical connections and improved heat dissipation by using a metal plate and soldering connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If aluminum wire is used to connect the IGBT chip to external electrodes, then electrical connection is achieved, but the chip size is limited by the wire diameter and heat dissipation is impaired
Solution Approach 1:
The patent extracts the aluminum wire connection from the system and replaces it with a solder-based extraction electrode structure. The extraction electrode extends from the rear surface of the substrate to the front surface, providing both electrical connection and heat dissipation pathways without being constrained by wire diameter limitations.
Solution Approach 2:
The patent transitions from a top-only connection approach to a three-dimensional connection structure where the extraction electrode extends through the substrate thickness. This vertical dimension allows the chip size to be reduced independently of the connection structure footprint on the chip surface.
2Temperature
If aluminum wire is connected directly to the chip from above, then electrical connection is established, but heat dissipation to the upper portion is reduced
Solution Approach 1:
The connection structure is segmented into multiple functional parts: the extraction electrode extending through the substrate, the solder layer providing thermal and electrical connection, and the external electrode. This segmentation allows heat dissipation to occur through multiple pathways rather than relying solely on the aluminum wire.
Solution Approach 2:
The solder acts as an intermediary material between the extraction electrode and the external electrode, providing both thermal and electrical connection. This intermediary enables efficient heat transfer from the chip through the substrate to the external electrode while maintaining electrical connectivity.
3Area of stationary object
If the contact area with aluminum wire is reduced, then chip size can be reduced, but heat cycle life becomes insufficient
Solution Approach 1:
The patent changes the connection parameters by using solder instead of aluminum wire, allowing for a larger effective contact area between the extraction electrode and the chip. This increased contact area improves heat cycle life while enabling smaller chip dimensions.
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
This design enables chip size reduction without being limited by wire diameter, enhances manufacturing efficiency, and improves heat dissipation by allowing for uniform solder thickness and centralized temperature monitoring.
Implementation Method 1
improves heat dissipation by allowing for uniform solder thickness
Data Source
AI summary
First and second connection electrodes are formed separately to be opposed to each other on an emitter electrode of an IGBT. Other first and second connection electrodes are formed separately to be opposed to each other on an anode electrode of a diode. A first electrode interconnection part extends from one side portion of an extraction electrode and is bent inwardly. A second electrode interconnection part extends from the other side portion to be opposed to the first electrode interconnection part. The first and second electrode interconnection parts located to face the IGBT are soldered only to the first and second connection electrodes, respectively. Similarly, the first and second electrode interconnection parts located to be opposed to the diode are soldered only to the other first and second connection electrodes, respectively.