Semiconductor Substrate With Thickened Peripheral Region
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Solution Overview
Problem
Semiconductor devices with thin substrates face challenges in maintaining chip strength while reducing on-state resistance, as thinner substrates are more susceptible to cracking and damage during manufacturing and handling due to increased stress and shear forces.
Innovation Solution
A semiconductor device design featuring a thin first semiconductor layer and a semiconductor substrate with a thicker peripheral region, where the first and second metal films are strategically positioned to reduce stress differences and enhance overall strength, combined with a manufacturing method that includes etching and metal film formation to achieve a conductor portion with reduced thickness and increased strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the semiconductor substrate is reduced to minimize on-state resistance, then the on-state resistance decreases, but the chip strength and susceptibility to cracking increases
Solution Approach 1:
The semiconductor substrate is designed with non-uniform thickness: a thin inner region (10 microns or less) for low on-state resistance, and a thicker peripheral region for strength and crack prevention. This local differentiation allows each region to fulfill its specific functional requirement.
Solution Approach 2:
The substrate thickness is segmented into two distinct regions: an inner region with reduced thickness for electrical performance and a peripheral region with greater thickness for mechanical strength. The metal films are also segmented to cover only specific areas rather than the entire substrate surface.
2Reliability
If the thickness of the semiconductor substrate is reduced, then the on-state resistance decreases, but the susceptibility to damage during manufacturing and handling increases
Solution Approach 1:
The thicker peripheral region specifically addresses the harmful factor of substrate damage during handling, while the thin inner region maintains low on-state resistance. The peripheral acts as a protective frame that absorbs mechanical stress without affecting the electrical performance of the central region.
3Reliability
If metal films are applied to cover the entire substrate surface, then electrical connectivity is improved, but stress concentration and cracking risk increase
Solution Approach 1:
Metal films are applied selectively only to the inner region of the substrate where electrical connectivity is needed, rather than covering the entire surface including the peripheral region. This localized application reduces overall stress in the structure while maintaining necessary electrical connections.
Solution Approach 2:
The metal film coverage is extracted from the peripheral region, removing the source of stress concentration in areas where metal coverage is not electrically necessary. This leaves the peripheral region free of metal-induced stress while the inner region retains full metal coverage for conductivity.
Data Source
AI summary
A semiconductor device includes a first semiconductor layer having a first surface and a second surface. A first metal film is disposed on the first surface. An outer portion of the first surface beyond an outer periphery of the first metal film is left uncovered by the first metal film. A semiconductor substrate has an inner region of a first thickness and a peripheral region of a second thickness, greater than the first thickness. A portion of the first semiconductor layer is between the inner region and the first metal layer. The peripheral region of the semiconductor substrate is below the outer portion of the first surface of the first semiconductor layer. A second metal film is below the inner region of the semiconductor substrate and adjacent to the peripheral region of the semiconductor substrate.