Semiconductor Stress Liner Structure for Etch Resistance
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Solution Overview
Problem
The existing method for forming a stress liner film in semiconductor devices results in insufficient stress application to the channel region due to low etch resistance and film thickness loss during the etching process of the dummy gate insulating film.
Innovation Solution
A semiconductor device and manufacturing method that incorporate a first stress film with superior etch resistance, formed over the sidewall of the gate electrode, and a second stress film with the same type of stress, applied outside the first stress film, to maintain stress application to the channel region while minimizing film thickness loss during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer stress liner film is used, then the structure is simple, but the etch resistance is insufficient causing film thickness loss during etching
Solution Approach 1:
The stress liner film is divided into multiple layers: a first stress liner film with high etch resistance and a second stress liner film with different stress characteristics. This segmentation allows each layer to perform its specific function - the first layer protects against etching while the second layer provides stress control, resolving the contradiction between structural simplicity and etch resistance.
Solution Approach 2:
The patent uses composite material structure by combining different stress liner film materials with distinct properties. The first stress liner film material is selected for superior etch resistance, while the second layer material provides complementary stress characteristics, creating a composite structure that achieves both protection and functional performance.
2Duration of action of moving object
If the stress liner film is formed early in the process, then stress application is established, but the film undergoes thickness loss during subsequent etching steps
Solution Approach 1:
The first stress liner film is formed early in the manufacturing process before the gate electrode is created. This preliminary action establishes the stress application framework in advance, allowing the stress to be maintained throughout subsequent processing steps while the high etch resistance of the first layer prevents significant thickness loss.
Solution Approach 2:
The first stress liner film with high etch resistance serves as a protective cushion that prevents the underlying second stress liner film from undergoing thickness loss during etching operations. This beforehand cushioning ensures that the stress application is maintained without the detrimental effect of film thinning.
3Ease of manufacture
If a single-layer stress liner film is used, then the manufacturing process is simple, but sufficient stress cannot be applied to the channel region
Solution Approach 1:
The stress liner film is segmented into two functional layers: the first layer provides etch resistance and structural stability, while the second layer is optimized for stress application to the channel region. This segmentation allows each layer to be optimized for its specific purpose, achieving sufficient stress application without overly complicating the manufacturing process.
Solution Approach 2:
Different regions of the stress liner film structure are assigned different qualities - the first layer has high etch resistance for protection, while the second layer has optimized stress characteristics for channel region control. This local quality differentiation allows the structure to simultaneously achieve ease of manufacture and effective stress application.
Data Source
AI summary
A semiconductor device includes: a sidewall insulating film; a gate electrode; source and drain regions; a first stress film; and a second stress film.