Power Semiconductor Conductor Recesses for Solder Fatigue Relief
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Solution Overview
Problem
In power semiconductor devices, the connecting material between the conductor plate and insulating substrate experiences significant strain due to repeated heating and cooling cycles, leading to concerns about fatigue fracture, especially with high operating voltages and large temperature rises.
Innovation Solution
The design incorporates recesses in the peripheral portions of the conductors connected to the insulating substrate, increasing the thickness of the connecting material in these areas to reduce strain and prevent fatigue fracture, while maintaining efficient heat dissipation through the use of high thermal conductivity materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the connecting material connects the conductor plate and the insulating substrate with a large area, then the electrical connection is improved, but the strain of the connecting material becomes large leading to fatigue fracture
Solution Approach 1:
The patent applies local quality by creating a recess in the conductor plate at the peripheral portion where the connecting material is applied. This recess increases the thickness of the connecting material specifically at the peripheral portion where strain is highest, while maintaining a thinner profile in the central area. This localized thickening strengthens the connecting material where it is most needed to resist fatigue fracture from thermal cycling, without unnecessarily increasing the overall connection area or compromising electrical performance.
2Power
If the power semiconductor device operates at high voltage, then the power conversion capability is improved, but the temperature rise and strain on connecting material increases
Solution Approach 1:
The recess structure creates local quality differentiation in the connecting material thickness. The increased thickness at the peripheral portion provides better thermal management at the boundaries where heat accumulation is most severe during high-power operation. This localized structural enhancement helps dissipate heat more effectively at critical stress points without requiring a complete redesign of the entire connection structure.
Solution Approach 2:
The recess is designed in advance to provide cushioning against the anticipated thermal and mechanical stresses that will occur during high-power operation. By pre-positioning the recess structure, the design anticipates the thermal cycling and strain that will occur during normal operation, creating a built-in buffer zone that absorbs these stresses before they can cause fatigue fracture.
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 effectively reduces solder strain, preventing fatigue fracture and enhancing the reliability of power semiconductor devices by managing thermal resistance and maintaining efficient heat dissipation.
Implementation Method 1
the connecting material that connects the conductor plate and the insulating substrate has a large amount of temperature rise
Implementation Method 2
when the power semiconductor element repeatedly generates heat (when the power semiconductor device repeatedly operates and stops), the connecting material is repeatedly applied with a large strain
Data Source
AI summary
A power semiconductor device includes an insulating substrate on which a first conductor layer is arranged on one surface, a first conductor that is connected to the first conductor layer via a first connecting material, and a semiconductor element that is connected to the first conductor via a first connecting material. When viewed from a direction perpendicular to an electrode surface of the semiconductor element, the first conductor includes a peripheral portion formed larger than the semiconductor element. A first recess is formed in the peripheral portion so that a thickness of the first connecting material becomes thicker than other portions.