Wide-Bandgap Semiconductor Module Edge Buffering Against Thermal Stress

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Solution Overview

Problem

Wide-bandgap semiconductor elements, such as SiC and GaN, experience stress concentration at their edge parts due to thermal expansion differences with sealing resins, leading to peeling and cracking issues.

Innovation Solution

A buffer member with a thickness of at least 50 μm is applied to cover the edge parts of the semiconductor elements, made from materials like polyimide or polyamide-imide, to alleviate thermal stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a wider buffer member is used to cover the edge part, then stress concentration is reduced, but manufacturing precision becomes more difficult to control

Engineering Contradiction:

Improvestress resistanceVSAvoidbuffer member thickness control

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The invention specifies a minimum thickness parameter of 50 μm for the buffer member, transforming the design from a qualitative concept to a quantitative specification. This parameter change ensures sufficient stress distribution area while providing a clear manufacturing target, resolving the contradiction between stress resistance and manufacturing precision by establishing a definitive threshold value.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the buffer member thickness is increased to reduce stress concentration, then reliability improves, but device complexity increases

Engineering Contradiction:

Improvepeeling and cracking preventionVSAvoidbuffer member structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention applies the buffer member specifically at the edge part of the semiconductor element where stress concentration occurs, rather than uniformly across the entire element. This local application approach improves reliability at the critical stress point while minimizing the overall added complexity and material usage.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The buffer member acts as an intermediary layer between the semiconductor element and the sealing resin, mediating the thermal stress transmission. This intermediate structure absorbs and distributes stress, preventing direct stress transfer that would cause peeling and cracking, thereby improving reliability without significantly increasing device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 buffer member effectively reduces stress concentration, preventing peeling and cracking at the adhesive interface between the semiconductor element and the sealing resin.

Implementation Method 1

Due to heat generated while the semiconductor element is operating, thermal stress occurs between the semiconductor element and the sealing resin. As the difference in coefficient of thermal expansion between the semiconductor element and the sealing resin increases, the occurring thermal stress increases.

Methodology Applied

Scientific EffectThermal stress: Thermal Expansion

Data Source

PatentUS12512378B2Semiconductor module and semiconductor module manufacturing method

Publication Date: 2025.12.30 FUJI ELECTRIC CO LTD

AI summary

A semiconductor module includes a semiconductor element made of a wide-bandgap semiconductor, the semiconductor element having an upper surface with an edge, a buffer member that covers the edge of the upper surface of the semiconductor element, and a sealing resin that seals the semiconductor element and the buffer member. The buffer member has a thickness equal to or larger than 50 μm.