Plasma Chamber Dry Cleaning with Shifted Dummy Wafer Coverage
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Solution Overview
Problem
Existing dry cleaning methods for plasma processing apparatuses face inefficiencies in removing deposits from shadow regions due to blocking by dummy wafers, leading to reduced sputtering efficiency and potential damage to the stage when wafer-less methods are used.
Innovation Solution
A method involving the use of multiple dummy substrates positioned strategically relative to the stage to expose shadow regions for dry cleaning, either by shifting the dummy wafers or using smaller diameter dummy wafers to ensure thorough removal of deposits from the plasma processing apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dummy wafer is placed on the stage during dry cleaning, then the stage is protected from damage, but shadow regions behind the dummy wafer cannot be cleaned effectively due to blocking
Solution Approach 1:
The cleaning process is divided into multiple segments: first cleaning the exposed regions, then repositioning the dummy wafer to clean previously shadowed regions. This segmentation allows comprehensive cleaning without requiring the dummy wafer to be removed, thus protecting the stage while achieving complete coverage.
Solution Approach 2:
The dummy wafer is made dynamic by repositioning it to different locations on the stage during the cleaning process. This allows regions that were previously in shadow to become exposed to the plasma, enabling complete cleaning coverage while maintaining stage protection throughout the process.
2Manufacturing precision
If wafer-less dry cleaning is performed without a dummy wafer, then shadow regions are exposed for cleaning, but the stage may be damaged by direct plasma exposure
Solution Approach 1:
The dummy wafer is placed on the stage before the dry cleaning process begins, establishing protective coverage in advance. This preliminary action allows the cleaning plasma to be generated without direct exposure to the stage, preventing damage while enabling subsequent repositioning to clean shadow regions.
Solution Approach 2:
The dummy wafer serves as an intermediary that mediates between the cleaning plasma and the stage. It protects the stage from direct plasma exposure while still allowing the plasma to clean surfaces when strategically repositioned, thus enabling complete cleaning without stage damage.
3Manufacturing precision
If the dummy wafer is repositioned multiple times during cleaning, then complete coverage including shadow regions is achieved, but the cleaning process time increases
Solution Approach 1:
The dummy wafer remains on the stage throughout the entire cleaning process, continuously providing protection while enabling cleaning. By repositioning rather than removing and replacing, the process maintains continuity, reducing idle time and achieving complete coverage efficiently.
Solution Approach 2:
The cleaning process uses periodic repositioning of the dummy wafer at strategically determined intervals. This periodic action ensures that all regions including shadow areas receive appropriate cleaning exposure while minimizing the total time the process takes to complete.
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 effectively removes deposits from previously inaccessible shadow regions, improving product yield and extending the operational time of the plasma processing apparatus by ensuring comprehensive cleaning without damaging the stage.
Implementation Method 1
performing a first dry cleaning process inside the chamber
Implementation Method 2
reduced sputtering efficiency
Data Source
AI summary
A method of cleaning a plasma processing apparatus includes: disposing a first dummy substrate at a first position with respect to a stage inside a chamber and performing a first dry cleaning process inside the chamber; and disposing a second dummy substrate at a second position with respect to the stage inside the chamber and performing a second dry cleaning process inside the chamber, wherein each of a center of the first position and a center of the second position is located at a different position from a center of the stage in a plan view, and wherein the first position and the second position are different from each other in a plan view.