Deep Trench Isolation Sequence for Leakage Reduction
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Solution Overview
Problem
In semiconductor device manufacturing, performing the Deep Trench Isolation (DTI) process before forming device structures like a source and drain can lead to thermal stress issues, requiring additional processes to mitigate these effects, which complicates the manufacturing process and increases costs.
Innovation Solution
The DTI process is performed immediately after forming a gate electrode or silicide structure, allowing for improved insulation and reducing thermal stress by forming a deep trench with an air gap and sidewall insulating films, which simplifies the manufacturing process and enhances device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the DTI process is performed before forming device structures, then device isolation and reduced current leakage are achieved, but thermal stress issues occur requiring additional processes
Solution Approach 1:
The patent inverts the conventional sequence by performing the DTI process after forming device structures (gate electrode and silicide) instead of before. This reversal eliminates thermal stress issues that would otherwise require additional mitigation processes, while still achieving effective device isolation and current leakage prevention.
2Stability of the object's composition
If additional processes are performed to release thermal stress, then thermal stress effects are reduced, but manufacturing time and cost increase
Solution Approach 1:
By inverting the process sequence to perform DTI after device structure formation, the patent eliminates thermal stress issues at their source, making additional stress relief processes unnecessary and thereby reducing manufacturing time and cost.
Solution Approach 2:
The patent extracts the thermal stress problem from the manufacturing process by changing the sequence, thereby removing the need for separate stress relief processes and their associated time and cost penalties.
3Reliability
If the DTI process is performed before silicide process, then device isolation is achieved, but thermal stress affects the trench structure
Solution Approach 1:
The patent inverts the conventional sequence by performing DTI after silicide process and device structure formation. This ensures the trench structure is not affected by subsequent thermal stress from annealing processes, while still achieving effective device isolation.
Data Source
AI summary
A semiconductor device and a manufacturing method thereof are provided. The semiconductor device includes: a deep trench in a substrate; a sidewall insulating film on a side surface of the deep trench; an interlayer insulating film on the sidewall insulating film; and an air gap in the interlayer insulating film.