Semiconductor Device Step Structure Joining Component
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Solution Overview
Problem
In power semiconductor devices, thermal stresses at the interface of materials with different linear thermal expansion coefficients lead to stress concentration on the joining component, which can cause increased electrical and thermal resistance when attempting to absorb and dissipate this stress by thickening the joining component, compromising device performance.
Innovation Solution
A semiconductor device design featuring a metal connector with a step structure, where the second portion of the joining component is thicker than the first portion, allowing for stress relief without increasing the overall thickness, thereby maintaining low electrical and thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the joining component is increased to absorb and dissipate stress, then the reliability of the joint is improved, but the electrical resistance and thermal resistance of the joining component increase
Solution Approach 1:
The joining component is designed with non-uniform thickness, featuring a first thickness in the stress concentration region and a second thickness (greater than the first) in the end surface region. This local variation in thickness allows stress absorption where needed while minimizing thermal resistance in the main conduction path.
Solution Approach 2:
The solution transitions from a uniform one-dimensional thickness to a two-dimensional thickness distribution across the joining component. By varying thickness in the planar direction rather than uniformly increasing it, the design achieves stress relief without proportionally increasing thermal resistance.
2Reliability
If the thickness of the joining component is increased to absorb and dissipate stress, then the reliability of the joint is improved, but the electrical resistance of the joining component increases
Solution Approach 1:
The joining component features localized thickness variation, with increased thickness only in specific regions (end surfaces and side surfaces) where stress concentration occurs, while maintaining thinner sections in areas where electrical conduction is prioritized.
Solution Approach 2:
The joining component is effectively segmented into regions of different thicknesses, with the thicker portions positioned strategically at stress-prone areas and thinner portions at conduction-critical areas, optimizing both mechanical and electrical performance.
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 effectively reduces the risk of crack or peeling in the joining component while maintaining low electrical and thermal resistance, enhancing the reliability and strength of the joint between the semiconductor chip and the metal connector.
Implementation Method 1
Due to thermal stresses in reliability evaluations of semiconductor devices (e.g., reflow evaluation and temperature cycle test), stress generally occurs at an interface of materials having a different linear thermal expansion coefficients
Implementation Method 2
the thickness of the joining component between the semiconductor chip and the connector also becomes thicker, thereby causing not only an increase in the thermal resistance
Implementation Method 3
the thickness of the joining component between the semiconductor chip and the connector also becomes thicker, thereby causing not only an increase in the thermal resistance but also an increase in electrical resistance
Data Source
AI summary
A semiconductor device includes metal connector plate having a first lower surface, facing an electrode of a semiconductor chip, a first end surface, a second end surface, and a second lower surface connecting the first end surface and the second end surface. In a first direction parallel to the semiconductor chip, an end surface of the electrode is located between the positions of the first end surface and the second end surface. A distance from the second lower surface to the electrode is greater than a distance from the first lower surface to the electrode. A joining component has a first portion between the first lower surface and the electrode and a second portion between the second lower surface and the electrode.