Plasma Chamber Cross-Flow Layout for Uniform Wafer Processing
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Solution Overview
Problem
Traditional plasma chambers experience non-uniformity issues due to axisymmetric gas flow causing pressure and concentration gradients, leading to deformation of gas inlet holes and increased costs from frequent showerhead replacements.
Innovation Solution
A plasma treatment chamber with multiphase rotating modulated gas cross-flow using multiple injectors and pump ports along the sidewalls, eliminating the need for showerheads by rotating gas flows across the workpiece to maintain uniformity and prevent plasma non-uniformity.
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 introduces asymmetric gas injection by placing gas inlet holes at specific angular positions (e.g., 0°, 90°, 180°, 270°) around the showerhead periphery instead of uniform radial distribution. This asymmetric arrangement creates controlled gas flow patterns that eliminate pressure gradients and achieve uniform plasma distribution across the wafer surface, resolving the contradiction between simplified gas distribution and processing uniformity
Solution Approach 2:
The system dynamically controls gas flow by independently adjusting the flow rates to each asymmetrically positioned gas inlet hole. This dynamic gas distribution control allows real-time optimization of plasma uniformity across different processing conditions, maintaining processing precision while keeping the overall system relatively simple
2Productivity
If gas inlet holes are positioned close to dense plasma region, then gas injection efficiency is improved, but extraneous plasma forms and non-uniformity changes over time
Solution Approach 1:
The patent applies local quality by creating an extraneous plasma region with different characteristics than the main processing plasma. Gas inlet holes are positioned to inject gas into this separate extraneous plasma zone rather than directly into the dense processing plasma region. This local differentiation allows efficient gas injection while preventing contamination and non-uniformity in the main plasma, maintaining long-term reliability
Solution Approach 2:
The plasma chamber is segmented into distinct regions: the main processing plasma region and a separate extraneous plasma region. Gas injection is directed into the extraneous plasma zone, physically separating the gas delivery function from the main plasma processing zone. This segmentation prevents plasma non-uniformity from developing in the processing region over time while maintaining injection efficiency
3Ease of operation
If showerheads are used with gas inlet holes, then gas distribution is achieved, but hole deformation from ion bombardment requires frequent replacements increasing cost
Solution Approach 1:
The patent extracts the gas injection function from the traditional showerhead structure by positioning gas inlet holes in the chamber wall or support structure rather than in a separate replaceable showerhead component. This extraction eliminates the showerhead as a consumable part, removing the need for frequent replacements while maintaining effective gas distribution through the asymmetric hole arrangement
Solution Approach 2:
By eliminating the showerhead entirely and integrating gas injection directly into the chamber structure, the patent removes the disposable component that required frequent replacement. The integrated design makes the gas distribution system permanent and maintenance-free, converting a consumable component into a lasting structural feature
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 solution achieves improved process uniformity and reduces the need for frequent showerhead replacements, minimizing plasma non-uniformity and maintaining consistent plasma characteristics over time.
Implementation Method 1
A first gas injector along the one or more sidewalls injects a first gas flow in a first direction generally parallel to and across a surface of the workpiece
Implementation Method 2
a first pump port along the one or more sidewalls generally opposite of the first gas injector pumps out the first gas flow
Implementation Method 3
During a plasma etch, deposition or other treatment processes, a workpiece, such as a semiconductor wafer, is inserted to a sealed plasma reactor chamber
Data Source
AI summary
Embodiments disclosed herein include a plasma treatment chamber, comprising one or more sidewalls. A support surface within the one or more sidewalls holds a workpiece. A first gas injector along the one or more sidewalls injects a first gas flow in a first direction generally parallel to and across a surface of the workpiece. A first pump port along the one or more sidewalls generally opposite of the first gas injector pumps out the first gas flow. A second gas injector along the one or more sidewalls injects a second gas flow in a second direction generally parallel to and across the surface of the workpiece. A second pump port along the one or more sidewalls generally opposite of the second gas injector pumps out the second gas flow. The first and second gas flows comprise a process gas mixture and/or an independent gas injection (IGI) mixture.