FinFET Dummy Gate Planarization via Buffer Oxide Intermediary
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Solution Overview
Problem
The formation of stepped portions during the patterning of dummy gate films in FinFET fabrication leads to improper node separation, affecting the reliability of semiconductor devices.
Innovation Solution
A method involving the formation of a first dummy gate film on a substrate with a buffer oxide film pattern, smoothing it to expose the pattern, and then forming a second dummy gate film, followed by patterning to create a metal gate pattern, which ensures proper node separation and device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dummy gate film is formed on an active fin that projects from the base, then the FinFET structure is created, but stepped portions are formed during dummy gate film formation which preclude proper node separation
Solution Approach 1:
A buffer oxide film pattern is formed on the active fin before forming the dummy gate film. This preliminary structure prevents the formation of stepped portions during subsequent dummy gate film formation, enabling proper node separation while maintaining the FinFET structure.
Solution Approach 2:
The buffer oxide film pattern acts as an intermediary layer between the active fin and the dummy gate film. This intermediate structure eliminates the stepped portion problem by providing a planarized surface for dummy gate film deposition, thereby ensuring proper node separation.
2Adaptability or versatility
If the active fin projects from the base to create FinFET structure, then multi-gate functionality is achieved, but stepped portions form during dummy gate film formation
Solution Approach 1:
The buffer oxide film pattern is formed on the active fin before dummy gate film deposition. This preliminary action maintains the projected active fin structure for multi-gate functionality while preventing stepped portions during subsequent processing.
Solution Approach 2:
The buffer oxide film pattern serves as an intermediary that preserves the active fin's projected structure for multi-gate operation while eliminating stepped portions during dummy gate film formation through planarization.
3Ease of manufacture
If dummy gate film is patterned directly on projected active fin, then fabrication process is simplified, but node separation is compromised
Solution Approach 1:
The buffer oxide film pattern is formed as a preliminary step before dummy gate film deposition. This additional step prevents stepped portions and ensures proper node separation, improving reliability without significantly complicating the fabrication process.
Solution Approach 2:
The buffer oxide film pattern acts as an intermediary layer that maintains ease of manufacture by providing a planarized surface for dummy gate film formation, thereby ensuring proper node separation and device reliability.
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 prevents the formation of stepped portions, enabling accurate node separation and enhancing the reliability of semiconductor devices by maintaining the same height for the upper surfaces of the dummy gate films and buffer oxide films.
Implementation Method 1
The first dummy gate film may be smoothed to expose the buffer oxide film pattern
Data Source
AI summary
In a method for fabricating a semiconductor device, a substrate may be provided that includes: a base, an active fin that projects from an upper surface of the base and is integrally formed with the base, and a buffer oxide film pattern formed on the active fin in contact with the active fin. A first dummy gate film may be formed on the substrate to cover the buffer oxide film pattern and the first dummy gate film may be smoothed to expose the buffer oxide film pattern. A second dummy gate film may be formed on the exposed buffer oxide film pattern and the first dummy gate film.