Semiconductor Lead Structure for Substrate Thermal Stress Relief
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Solution Overview
Problem
Semiconductor devices with leads fixed to insulating substrates face thermal stress issues due to differences in linear expansion coefficients, leading to potential cracking from concentrated thermal stress.
Innovation Solution
A semiconductor device design where the substrate's dimension in one direction is larger than in another, with a lead having a first region overlapping a semiconductor element and a second region separated from it, where the second region's thickness is smaller, alleviating thermal strain by dissipating it along the second direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the metal pattern is fixed to the insulating substrate using a bonding layer such as solder, then the metal pattern is securely attached to the substrate, but thermal stress concentration occurs at the interface due to difference in linear expansion coefficients, potentially causing cracks on the substrate
Solution Approach 1:
The lead is designed with varying thickness along its length, creating local quality differences. The first region has a first thickness while the second region has a second thickness different from the first, allowing different portions of the lead to handle thermal expansion differently and reducing stress concentration at the substrate interface
Solution Approach 2:
The lead is segmented into multiple regions with different thicknesses. This segmentation allows the lead to accommodate thermal expansion in a distributed manner rather than concentrating stress at a single location, thereby reducing the risk of substrate cracking
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 reduces thermal stress concentration on the substrate, enhancing bonding strength and preventing dislocation of semiconductor elements by distributing thermal expansion and contraction effectively.
Implementation Method 1
thermal strain occurs on the interface between the insulating substrate and the metal pattern due to a difference of linear expansion coefficients of the insulating substrate and the metal pattern
Data Source
AI summary
A semiconductor device, includes: a substrate having an obverse surface facing in a thickness direction; a first lead having a loading surface facing a side same as a side the obverse surface faces as to the thickness direction and being fixed on the obverse surface; and a first semiconductor element arranged on the loading surface. A dimension of the substrate in a first direction orthogonal to the thickness direction is larger than a dimension of the substrate in a second direction orthogonal to the thickness direction and the first direction. The first lead includes a first region overlapped with the first semiconductor element as viewed in the thickness direction and a second region separated from the first semiconductor element as viewed in the thickness direction, and at least a part of the second region extends along the second direction.