Void-Free SiNx Gap Fill via Segmented Deposition
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Solution Overview
Problem
The semiconductor industry faces challenges in forming seamless and void-free gap fill layers in high aspect ratio structures, leading to defects such as voids and seams in gap fill materials, which can cause device performance degradation due to premature sealing during deposition.
Innovation Solution
A multi-step deposition and in-situ treatment process using low Reactive Sticking Coefficient (RSC) molecules and assist gases like ammonia, helium, or nitrogen to form a silicon nitride (SiNx) gap fill layer, ensuring void-free and seamless layers through cycles of chemical vapor deposition and treatment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition processes are used to form gap fill layers, then deposition speed is maintained, but voids and seams form in high aspect ratio structures due to premature sealing
Solution Approach 1:
The deposition process is divided into multiple sequential deposition steps with intermediate treatments between them. Each deposition step deposits a portion of the gap fill layer, and intermediate treatments modify the layer properties to prevent premature sealing. This segmentation allows the process to handle high aspect ratio structures without forming voids and seams while maintaining overall deposition efficiency.
Solution Approach 2:
Intermediate treatments are performed between deposition steps to modify the gap fill layer properties before subsequent deposition continues. These preliminary actions include plasma treatments or chemical treatments that adjust the reactive sticking coefficient, preventing premature sealing and ensuring proper material distribution in high aspect ratio structures before the next deposition phase.
2Manufacturing precision
If deposition parameters are optimized for high aspect ratio structures, then void-free filling is achieved, but deposition time increases significantly
Solution Approach 1:
The process uses periodic cycles of deposition followed by intermediate treatments. Each cycle deposits material and then applies a treatment to modify layer properties. This periodic action maintains uniformity and prevents defects while managing total process time through efficient cycling rather than continuous slow deposition.
Solution Approach 2:
The intermediate treatments are designed to be quick processes that maintain continuous progress toward completing the gap fill layer. Rather than long interruptions, the treatments are optimized to be brief actions that reset the deposition conditions, allowing the useful action of material deposition to continue efficiently across multiple steps.
3Ease of manufacture
If single-step deposition is used, then process simplicity is maintained, but weak seams and voids form in the gap fill layer
Solution Approach 1:
The deposition process is divided into multiple sequential deposition steps with intermediate treatments between them. Each deposition step deposits a portion of the gap fill layer, and intermediate treatments modify the layer properties to prevent premature sealing. This segmentation allows the process to handle high aspect ratio structures without forming voids and seams while maintaining overall deposition efficiency.
Solution Approach 2:
Intermediate treatments are performed between deposition steps to modify the gap fill layer properties before subsequent deposition continues. These preliminary actions include plasma treatments or chemical treatments that adjust the reactive sticking coefficient, preventing premature sealing and ensuring proper material distribution in high aspect ratio structures before the next deposition phase.
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 enhances gap fill performance, eliminates weak seams, allows for controllable thickness, and improves device reliability by forming high-quality, void-free SiNx gap fill layers in both planar and high aspect ratio structures, including FinFETs.
Implementation Method 1
A multi-step deposition and in-situ treatment process using low Reactive Sticking Coefficient (RSC) molecules and assist gases like ammonia, helium, or nitrogen to form a silicon nitride (SiNx) gap fill layer
Implementation Method 2
The deposition process can be followed by an in-situ treatment process where the deposited silicon nitride gap fill layer is exposed to one or more plasma-activated assist gases
Data Source
AI summary
The present disclosure relates to a semiconductor device and a manufacturing method, and more particularly to a semiconductor device having an enhanced gap fill layer in trenches. The present disclosure provides a novel gap fill layer formed using a multi-step deposition and in-situ treatment process. The deposition process can be a flowable chemical vapor deposition (FCVD) utilizing one or more assist gases and molecules of low reactive sticking coefficient (RSC). The treatment process can be an in-situ process after the deposition process and includes exposing the deposited gap fill layer to plasma activated assist gas. The assist gas can be formed of ammonia. The low RSC molecule can be formed of trisilylamin (TSA) or perhydropolysilazane (PHPS).