Cross-Flow Plasma Chamber for Uniform Multiphase Deposition
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Solution Overview
Problem
Traditional plasma chambers experience non-uniformity issues due to axisymmetric gas flow, leading to pressure and concentration gradients, and extraneous plasma formation at gas inlet holes, which complicates the control of gas flow direction and timing for different phases during plasma etch or deposition processes.
Innovation Solution
A plasma chamber with a rotatable pedestal and cross-flow pumping ring that injects gas parallel to the workpiece surface, using microwave resonators to ignite plasma, allowing for multiphase cyclic deposition by rotating the workpiece between gas flow phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If axisymmetric gas flow is used in traditional plasma chambers, then gas distribution is simplified, but pressure and concentration gradients cause center-to-edge processing non-uniformity
Solution Approach 1:
The patent applies asymmetry by implementing a cross-flow gas distribution system where gas enters through inlet holes in the sidewalls of the plasma chamber and flows horizontally across the wafer surface, rather than using axisymmetric vertical flow. This asymmetric flow pattern eliminates pressure and concentration gradients in the radial direction, achieving uniform processing across the wafer while maintaining system simplicity
2Device complexity
If gas inlet holes are positioned near dense plasma regions, then gas distribution is simplified, but extraneous plasma forms causing non-uniformity that changes over time
Solution Approach 1:
The patent extracts the gas inlet holes from the plasma-facing surface and relocates them to the sidewalls of the plasma chamber. This separation removes the gas distribution system from direct contact with dense plasma regions, preventing extraneous plasma formation and electrode degradation, thereby ensuring stable and reliable processing over time
3Device complexity
If the workpiece is fixed on the pedestal, then positioning is simplified, but a complex system is needed to change gas flow direction and timing for various phases
Solution Approach 1:
The patent inverts the conventional approach by making the pedestal and workpiece rotatable instead of keeping them fixed. The cross-flow gas system remains stationary with inlet holes positioned at specific angular locations. By rotating the workpiece to different angular positions during different phases, the system achieves variable gas flow exposure without requiring complex mechanisms to change gas flow direction, significantly simplifying the overall control system
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 configuration eliminates the need for showerheads, reduces plasma non-uniformity, and simplifies the control of gas flow phases, resulting in improved process uniformity and reduced complexity.
Implementation Method 1
A lid is over the cross-flow pumping ring, the lid having a plurality of microwave resonators to ignite the gas flow and form plasma
Implementation Method 2
microwave resonators to ignite the gas flow and form plasma
Data Source
AI summary
A plasma treatment chamber comprises a chamber body having an opening in a top surface thereof. A rotatable pedestal is within the chamber body having a support surface to hold and rotate a workpiece in a processing region. A cross-flow pumping ring is over the opening in the chamber body to inject a gas flow in a direction generally parallel to and across a surface of the workpiece. A lid is over the cross-flow pumping ring, the lid having a plurality of microwave resonators to ignite the gas flow and form plasma.