T-Shaped FinFET Device With Masking Cap Protection
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Solution Overview
Problem
The semiconductor industry faces challenges in integrating a fin-trim process into the fabrication of FinFET devices as they are scaled down, leading to issues with fin damage and reliability during subsequent etching and cleaning processes.
Innovation Solution
A method involving the formation of a masking cap using a first and second liner layer over the fin structure, which is patterned to remain on the top surface and sidewall, allowing for selective thinning of the fin structure while protecting the top portion, and subsequent etching to create a T-shaped fin profile, enhancing device performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the fin structure is thinned to enhance device performance, then the manufacturing precision and device performance are improved, but the fin structure becomes vulnerable to damage and collapse during subsequent etching and cleaning processes
Solution Approach 1:
A masking cap is formed over the fin structure before the thinning process begins. This preliminary protective action prevents damage to the fin structure during subsequent etching and cleaning processes, allowing the fin to be thinned to enhanced precision without compromising its structural integrity or reliability
Solution Approach 2:
The masking cap serves as an intermediary protective layer between the fin structure and the harmful etching/cleaning processes. It allows the fin to be thinned precisely while the masking cap absorbs the mechanical stress and prevents direct damage to the thinned fin structure
2Reliability
If a masking cap is formed to protect the fin structure during thinning, then the reliability is improved, but the device complexity and fabrication process complexity increase
Solution Approach 1:
The masking cap is segmented into specific regions: a first region that remains over the fin structure during thinning to provide protection, and a second region that is removed to allow access for subsequent gate formation. This segmentation allows selective protection where needed while maintaining process efficiency
Solution Approach 2:
The masking cap is designed as a temporary structure that is discarded after serving its protective function during fin thinning. The selective removal of the second region of the masking cap allows the process to proceed to gate formation without requiring complex removal steps, as the masking cap material is discarded after its protective purpose is fulfilled
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 approach enables the enhancement of device performance by maintaining the top portion of the fin structure intact, preventing damage and collapse during subsequent processes, thereby increasing the reliability and effectiveness of the FinFET device fabrication.
Implementation Method 1
forming a masking cap using a first and second liner layer over the fin structure
Implementation Method 2
forming a masking cap using a first and second liner layer over the fin structure
Implementation Method 3
The masking cap provides a protection of the top portion of the fin structure during the fin structure is thinned
Implementation Method 4
the fin structure is thinned by using the masking cap as an etch mask
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes an isolation feature over a substrate and a fin structure protruding from the substrate and partially surrounded by the isolation feature. The fin structure includes a first portion above the isolation feature and having a first width. The fin structure also includes a second portion extending from a top of the first portion and having a second width greater than the first width, so that the fin structure above the isolation feature has a T-shaped profile. The semiconductor device structure also includes a gate structure covering the first portion and the second portion of the fin structure.