Backside ESD Diode Integration Without Substrate Penetration
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Solution Overview
Problem
Existing semiconductor devices face challenges in integrating electrostatic discharge (ESD) diodes and transistors efficiently, particularly due to the need for substrate penetration for backside contact integration, which complicates the integration scheme and introduces parasitic effects.
Innovation Solution
A semiconductor device is designed with a diode and a logic device, featuring backside contacts that directly integrate with the base silicon material without a residual substrate, allowing for tighter integration and reduced parasitic effects by eliminating the need for substrate etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substrate penetration is used for backside contact integration, then electrical connection is achieved, but device complexity and parasitic effects increase
Solution Approach 1:
The patent transitions from vertical substrate penetration to horizontal direct contact at the base silicon surface. Backside contacts are formed by removing sacrificial placeholders and creating direct contact with the base silicon material, eliminating the need to etch through the entire substrate thickness. This dimensional change from depth-oriented to surface-oriented integration reduces process complexity and parasitic effects.
2Ease of manufacture
If substrate etching is performed for backside contact, then contact integration is achieved, but manufacturing complexity increases
Solution Approach 1:
Sacrificial placeholder structures are formed during the initial fabrication process before final device assembly. These placeholders occupy the positions where backside contacts will eventually be formed. By preparing these placeholders in advance and removing them only at the final stage, the patent avoids complex mid-process substrate etching operations and simplifies the manufacturing flow.
Solution Approach 2:
Sacrificial placeholder structures serve as intermediary elements that facilitate backside contact formation. These placeholders are temporarily introduced during fabrication, protect the base silicon surface during processing, and are removed only when ready for final contact formation. This intermediary approach eliminates the need for direct substrate etching and simplifies manufacturing.
3Strength
If residual substrate is kept for backside contact, then structural support is maintained, but parasitic effects increase
Solution Approach 1:
The patent extracts and removes the residual substrate material that would otherwise remain between the backside contacts and the base silicon. By completely removing sacrificial placeholders and forming direct contacts with the base silicon surface, the patent eliminates parasitic substrate effects while maintaining structural integrity through the placeholder framework during fabrication.
Data Source
AI summary
A semiconductor device includes a diode, the diode includes a first frontside contact over a first source/drain region, a first backside contact, and a first placeholder connected to a bottom surface of the first source/drain region.