Dual-RF Plasma Deposition Layout for Edge Film Uniformity
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Solution Overview
Problem
The challenge in semiconductor deposition processes is achieving uniformity of deposited layers, particularly at the edges of substrates, which affects device yield and efficiency, as existing methods often result in non-uniformities and defects due to the hollow cathode effect and sputtering when using low frequency (LF) RF power with high frequency (HF) power.
Innovation Solution
Applying LF RF power to the pedestal instead of the showerhead, combined with conditioning the chamber with dielectric layers like silicon oxide and silicon nitride, to improve film properties and reduce defects, while using both HF and LF RF power simultaneously to enhance material uniformity and ion bombardment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If low frequency RF power is applied to the showerhead with high frequency power, then ion bombardment and material deposition occur, but the hollow cathode effect causes non-uniformity and defects at substrate edges
Solution Approach 1:
The patent extracts the low frequency RF power application from the showerhead and relocates it to the pedestal. This separation removes the source of the hollow cathode effect from the deposition region while maintaining the beneficial ion bombardment effects at the substrate level, thereby eliminating non-uniformity and defects at substrate edges.
Solution Approach 2:
The patent introduces dielectric layers (silicon oxide and silicon nitride) as intermediary conditioning layers on the chamber walls. These layers act as mediators that modify the plasma environment and reduce the harmful hollow cathode effect, leading to improved film uniformity and reduced defects when low frequency RF is applied.
2Productivity
If low frequency RF power is applied to enhance ion bombardment, then material deposition occurs, but sputtering increases causing defects on substrates
Solution Approach 1:
The patent extracts low frequency RF power application from the showerhead where it causes sputtering, and relocates it to the pedestal where it provides beneficial ion bombardment without excessive sputtering. This spatial separation allows productive deposition while minimizing harmful material ejection and defect formation.
3Power
If low frequency RF power is applied at the showerhead, then plasma generation occurs, but non-uniformity at substrate edges increases
Solution Approach 1:
The patent extracts low frequency RF power application from the showerhead region and applies it instead to the pedestal. This relocation maintains effective plasma generation for deposition while eliminating the edge non-uniformity problem caused by hollow cathode formation in the showerhead apertures.
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 results in improved uniformity and reduced defects, with smaller grain sizes and smoother surfaces, effectively addressing the edge uniformity issues and increasing the yield of functional devices by minimizing the hollow cathode effect and sputtering.
Implementation Method 1
forming a plasma of the mixture within the processing region
Implementation Method 2
Applying low frequency (LF) radio frequency (RF) power along with high frequency (HF) RF power
Implementation Method 3
depositing the material on a substrate disposed on the pedestal
Implementation Method 4
enhance material uniformity and ion bombardment
Data Source
AI summary
A plasma processing system is described. The system may include a showerhead. The system may further include a first RF generator in electrical communication with the showerhead. The first RF generator may be configured to deliver a first voltage at a first frequency to the showerhead. Additionally, the system may include a second RF generator in electrical communication with a pedestal. The second RF generator may be configured to deliver a second voltage at a second frequency to the pedestal. The second frequency may be less than the first frequency. The system may also include a terminator in electrical communication with the showerhead. The terminator may provide a path to ground for the second voltage. Methods of depositing material using the plasma processing system are described. A method of seasoning a chamber by depositing silicon oxide and silicon nitride on the wall of the chamber is also described.