Plasma Uniformity via Multi-Point RF Coupling
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Solution Overview
Problem
Plasma processing chambers face challenges in achieving uniformity of thin film deposition and etching due to asymmetries in reactor configuration and the inability to connect radio-frequency power feeds at optimal locations, leading to non-uniform electric fields and plasma distribution.
Innovation Solution
The solution involves coupling a single radio-frequency power source to multiple points on the discharge electrode of the plasma processing chamber, with strategic positioning and power distribution, including the use of phase differences between coupling points, to compensate for non-uniformity patterns and enhance film uniformity without altering conventional process parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single radio-frequency power feed is connected at the center point of the discharge electrode, then a radially uniform electric field can be generated, but the connection point is inaccessible due to other external chamber components
Solution Approach 1:
The invention divides the single power feed connection into multiple separate connection points on the discharge electrode. Instead of requiring one centralized connection at the inaccessible center point, the system uses multiple connection points distributed around the electrode periphery, each accessible from outside the chamber. This segmentation allows the electric field to be constructed from multiple accessible sources, resolving the contradiction between achieving uniform field distribution and physical accessibility of connection points.
2Ease of operation
If the radio-frequency power feed is positioned on the discharge electrode at a point besides the geometric center, then accessibility is improved, but the electric field becomes non-symmetric and plasma distribution becomes non-uniform
Solution Approach 1:
The invention intentionally introduces controlled asymmetry through multiple discrete connection points positioned at specific locations around the discharge electrode periphery. Rather than attempting to maintain perfect radial symmetry from a single off-center point, the system uses an asymmetric arrangement of multiple power feeds that collectively generate a more uniform overall electric field distribution. This resolves the contradiction by transforming the problem from single-point asymmetric connection to multi-point distributed connection.
Solution Approach 2:
The invention combines multiple non-uniform electric field contributions from individually positioned power feeds into a composite uniform electric field. Each connection point generates its own electric field pattern, but when combined through proper power distribution and phasing, these individual non-uniform fields merge to create an overall uniform field distribution across the plasma processing region, thereby achieving both accessibility and uniformity.
3Manufacturing precision
If multiple radio-frequency power feeds are used to compensate for non-uniformity patterns, then film uniformity is improved, but the system complexity increases
Solution Approach 1:
The invention utilizes parameter changes in the form of relative phase shifts between multiple radio-frequency power feeds to achieve uniform film deposition. By adjusting the phase relationship between power feeds at different connection points, the system can compensate for chamber asymmetries and non-uniformity patterns without requiring complex hardware modifications. This parameter-based control approach resolves the contradiction by providing a flexible, software-controlled method to achieve uniformity while maintaining relatively simple hardware architecture.
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 significantly improves the uniformity of thin film deposition and etching by generating a more symmetrical electric field and plasma distribution, addressing the inherent asymmetries in the chamber configuration and enhancing the robustness of the plasma processing process.
Implementation Method 1
A single radio-frequency (RF) power source is coupled to multiple points on the discharge electrode of the plasma processing chamber
Implementation Method 2
Plasma processing, such as plasma-enhanced chemical vapor deposition (PECVD), is generally employed to deposit thin films on substrates
Data Source
AI summary
A system for modifying the uniformity pattern of a thin film deposited in a plasma processing chamber includes a single radio-frequency (RF) power source that is coupled to multiple points on the discharge electrode of the plasma processing chamber. Positioning of the multiple coupling points, a power distribution between the multiple coupling points, or a combination of both are selected to at least partially compensate for a consistent non-uniformity pattern of thin films produced by the chamber. The power distribution between the multiple coupling points may be produced by an appropriate RF phase difference between the RF power applied at each of the multiple coupling points.