Hydrogen Plasma Curing of FCVD a-Si Films Without Shrinkage
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Solution Overview
Problem
Conventional methods for curing amorphous silicon layers deposited using flowable chemical vapor deposition (FCVD) processes result in undesirable seams and voids due to low film density and physical softness, requiring additional processing steps and leading to substantial film shrinkage, which affects semiconductor device performance.
Innovation Solution
In-situ plasma treatment of amorphous silicon layers using a substantially silicon-free hydrogen treatment gas in the same processing chamber, with specific power and gas ratio conditions, to reduce hydrogen content and form denser Si—Si bonds, thereby increasing film density and reducing shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional curing methods (UV curing) are used to densify FCVD a-Si films, then film density and hardness are improved, but substantial shrinkage occurs (up to 70% volume shrinkage) and additional processing chambers are required
Solution Approach 1:
The patent combines the deposition and curing processes into a single processing chamber. The FCVD deposition and plasma treatment are performed sequentially in the same chamber without removing the substrate, eliminating the need for additional processing chambers and reducing substrate handling steps.
Solution Approach 2:
The patent uses plasma treatment with controlled parameters (power between 50-500 Watts, pressure between 1-100 mTorr, gas composition) to densify the a-Si film. By adjusting these plasma parameters, the film density is improved while minimizing shrinkage compared to conventional UV curing methods.
2Strength
If conventional curing methods are used, then film hardness is improved, but processing time increases due to chamber transitions and temperature stabilization
Solution Approach 1:
The deposition and curing operations are merged into a single chamber process. The substrate remains in the processing chamber throughout, eliminating transfer time and temperature stabilization requirements between chambers, thus reducing total processing time.
Solution Approach 2:
The plasma treatment is performed immediately after deposition while the substrate is still in the chamber, maintaining continuous processing. This eliminates idle time for chamber transitions and temperature adjustments, keeping the useful action continuous.
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
The plasma treatment method enhances film density, reduces shrinkage, and eliminates seams and voids, resulting in improved semiconductor feature formation and device performance by maintaining the processing within the same chamber, reducing total substrate processing time, and achieving higher film quality with reduced hydrogen content.
Implementation Method 1
forming a treatment plasma of the substantially silicon-free hydrogen treatment gas, and exposing the substrate having the amorphous silicon layer deposited on a surface thereof to the treatment plasma
Implementation Method 2
plasma treating an amorphous silicon layer includes flowing a substantially silicon-free hydrogen treatment gas into a processing volume of a processing chamber
Implementation Method 3
forming a deposition plasma of the processing gas, exposing the surface of the substrate to the deposition plasma, and depositing the amorphous silicon layer on the surface of the substrate
Implementation Method 4
amorphous silicon layer deposited using an FCVD process
Data Source
AI summary
Embodiments herein provide methods of plasma treating an amorphous silicon layer deposited using a flowable chemical vapor deposition (FCVD) process. In one embodiment, a method of processing a substrate includes plasma treating an amorphous silicon layer by flowing a substantially silicon-free hydrogen treatment gas into a processing volume of a processing chamber, the processing volume having the substrate disposed on a substrate support therein, forming a treatment plasma of the substantially silicon-free hydrogen treatment gas, and exposing the substrate having the amorphous silicon layer deposited on a surface thereof to the treatment plasma. Herein, the amorphous silicon layer is deposited using an FCVD process. The FCVD process includes positioning the substrate on the substrate support, flowing a processing gas into the processing volume, forming a deposition plasma of the processing gas, exposing the surface of the substrate to the deposition plasma, and depositing the amorphous silicon layer on the surface of the substrate.