Power Semiconductor Terminal Intermediate Portion Moisture Barrier
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Solution Overview
Problem
Power semiconductor devices face reliability issues due to moisture absorption by the sealing material when in contact with cooling water, leading to potential precipitation at the interface between the semiconductor element and resin, and increased heat generation and electric resistance with larger terminal protrusions.
Innovation Solution
The power semiconductor device features a metal first and second base on either side of the semiconductor element, with a sealing material between them, and an intermediate portion on the second terminal that increases distance away from the semiconductor element, preventing cooling water contact with the sealing material and enhancing cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the sealing material is in contact with cooling water to cool the semiconductor element, then cooling performance is improved, but the sealing material absorbs moisture leading to reduced reliability
Solution Approach 1:
The patent introduces an intermediary structure (the specifically configured second terminal with intermediate portion) that acts as a barrier between the cooling water and the sealing material. This intermediate portion prevents direct contact between the sealing material and cooling water, thereby preventing moisture absorption while still allowing heat dissipation to occur through the terminal structure.
Solution Approach 2:
The second terminal is segmented into different portions including the intermediate portion that serves a protective function. By dividing the terminal structure into functional segments, the patent enables one portion to provide cooling while another portion (the intermediate portion) provides protection against moisture ingress to the sealing material.
2Reliability
If the second terminal protrudes further to increase creepage distance for safety, then insulation performance is improved, but heat dissipation performance deteriorates
Solution Approach 1:
The patent applies local quality by giving different portions of the second terminal different functions: one portion is optimized for electrical insulation (providing adequate creepage distance), while another portion (the intermediate portion) is optimized for heat dissipation. This localized functional differentiation allows the terminal to simultaneously achieve both insulation performance and heat dissipation performance without compromising either.
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 configuration improves the reliability and cooling performance of the power semiconductor device by preventing moisture absorption, maintaining excellent insulation, and securing adequate creepage and space distances, while allowing for effective application of large currents without exceeding the glass transition temperature of the sealing material.
Implementation Method 1
the resin absorbs moisture up to a saturated state, so that the cooling water diffused to a minute peeling portion at the interface between the semiconductor element and the resin is precipitated
Implementation Method 2
a highly efficient cooling system using water cooling is employed for miniaturization and weight reduction
Implementation Method 3
securing adequate creepage and space distances
Data Source
AI summary
An object of the invention is to improve the reliability of a power semiconductor device. The power semiconductor device according to the invention includes a semiconductor element, a first terminal and a second terminal that transmit current to the semiconductor element, a first base and a second base that are disposed to face each other while interposing a part of the first terminal, a part of the second terminal, and the semiconductor element between the first base and the second base, and a sealing material that is provided in a space between the first base and the second base. The second terminal includes an intermediate portion formed in such a way that a distance from the first terminal increases along a direction away from the semiconductor element. The intermediate portion is provided between the first base and the second base and in the sealing material.