Gate Layer Gapfill in High Aspect Ratio Trenches
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Solution Overview
Problem
The semiconductor industry faces challenges in depositing films in high aspect ratio trenches without forming seams or voids, which can lead to fin bending and defects in FinFET devices during the fabrication of semiconductor devices.
Innovation Solution
A cyclic deposition-etching process is employed, followed by an anneal process to cause material reflow, and subsequent crystalline film deposition and annealing to densify the film, reducing or eliminating voids and seams in the trenches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a film is deposited in high aspect ratio trenches using conventional methods, then the trenches can be filled, but seams and voids form in the deposited film
Solution Approach 1:
The deposition process is divided into multiple cycles of depositing a first portion, annealing to cause lateral flow, and depositing a second portion. This segmentation allows each layer to be properly formed and densified before the next is added, preventing void formation while maintaining film quality in high aspect ratio trenches
Solution Approach 2:
The first portion of the film is deposited and annealed to cause lateral flow along the trench walls before the second portion is deposited. This preliminary action ensures proper film formation and densification in the trench regions, preventing voids and seams in the final film structure
2Productivity
If conventional deposition is used in high aspect ratio trenches, then deposition can be completed, but fin bending occurs due to voids and seams
Solution Approach 1:
The deposition is segmented into multiple cycles with intermediate annealing steps. Each cycle deposits a portion and allows lateral flow to densify the film before the next deposition, preventing void formation that would cause fin bending while maintaining overall deposition efficiency
Solution Approach 2:
The process parameters are changed by introducing annealing temperature and duration control between deposition cycles. This allows the film to undergo lateral flow and densification at controlled conditions, preventing fin bending while maintaining deposition productivity
3Manufacturing precision
If cyclic deposition-etching is performed, then film coverage is improved, but the process complexity increases
Solution Approach 1:
The deposition and annealing operations are merged into integrated process cycles. The lateral flow during annealing automatically improves film coverage and densification without requiring additional etching or deposition steps, reducing overall process complexity while maintaining precision
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 method effectively fills high aspect ratio trenches without seams or voids, reducing fin bending and minimizing defects in the semiconductor device structure.
Implementation Method 1
an anneal process can be performed on the deposited layer to cause the material of the film or layer to reflow
Implementation Method 2
cause the material of the film or layer to reflow
Implementation Method 3
a crystalline film or layer (e.g., polycrystalline) can be deposited, and another anneal process can be performed
Implementation Method 4
another anneal process can be performed. The reflow process, the deposition of the crystalline film or layer, and the anneal process can reduce or eliminate voids or seams
Data Source
AI summary
Embodiments disclosed herein relate generally to forming a gate layer in high aspect ratio trenches using a cyclic deposition-etch process. In an embodiment, a method for semiconductor processing is provided. The method includes performing a cyclic deposition-etch process to form a conformal film over a bottom surface and along sidewall surfaces of a feature on a substrate. The method includes reflowing the conformal film. The method includes forming a cap layer on the reflowed film. The method includes depositing a crystalline film on the cap layer. The method includes crystallizing the reflowed film and the cap layer after depositing the crystalline film.