Tunable Ground Planes for Plasma Chamber Uniformity
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Solution Overview
Problem
Conventional plasma processing systems face challenges in achieving uniform etching and deposition due to non-uniformity in plasma distribution, leading to edge effects and reduced device yield, where the periphery of substrates often lacks material deposition or experiences excessive build-up, affecting processing throughput and device integrity.
Innovation Solution
The implementation of a secondary ground plane with a tunable electric field, featuring electrodes with angled surfaces and zoned showerhead assemblies, allows for improved control of plasma distribution by generating axial and radial electric field components within the processing volume, ensuring complete substrate coverage and minimizing edge effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional parallel plate reactor plasma processing is used, then deposition can be achieved, but non-uniform plasma distribution causes edge effects and reduced device yield
Solution Approach 1:
The ground plane is segmented into multiple independently biasable zones (first ground plane portion, second ground plane portion, third ground plane portion) that can be controlled separately. This segmentation allows different regions of the plasma chamber to have different plasma densities, enabling uniform deposition across the substrate by compensating for edge effects through localized control of plasma distribution.
2Manufacturing precision
If conventional plasma distribution control is used, then processing can be maintained, but peripheral substrate regions lack material deposition or experience excessive build-up
Solution Approach 1:
Different zones of the ground plane are assigned different bias voltages to create locally optimized plasma conditions. The first ground plane portion (opposing the substrate) and second ground plane portion (on the showerhead assembly) can be independently biased to control plasma distribution in specific regions, ensuring uniform material deposition across the entire substrate surface.
3Manufacturing precision
If conventional plasma chambers are used, then deposition occurs, but excessive material build-up on periphery requires subsequent polishing that reduces throughput
Solution Approach 1:
The plasma distribution is pre-adjusted during the deposition process itself by applying specific bias voltages to different ground plane zones before deposition begins. This preliminary control of plasma uniformity prevents excessive material build-up on peripheral regions, eliminating the need for subsequent polishing operations and maintaining high processing throughput.
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 solution enhances the uniformity of plasma distribution, reducing edge effects and improving deposition quality across the substrate, thereby increasing device yield and reducing the need for subsequent polishing processes that can damage the substrate.
Implementation Method 1
the one or more electrodes are adapted to generate a tunable electric field inside the processing volume having axial and radial components
Implementation Method 2
Plasma enhanced processes, such as plasma enhanced chemical vapor deposition (PECVD) processes
Data Source
AI summary
An apparatus and method are provided for controlling the intensity and distribution of a plasma discharge in a plasma chamber. In one embodiment, a shaped electrode is embedded in a substrate support to provide an electric field with radial and axial components inside the chamber. In another embodiment, the face plate electrode of the showerhead assembly is divided into zones by isolators, enabling different voltages to be applied to the different zones. Additionally, one or more electrodes may be embedded in the chamber side walls.