Plasma Processing Chamber Coating for Etching Stability
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Solution Overview
Problem
Existing plasma processing technologies face challenges in maintaining consistent etching performance and throughput due to residual metal deposits on the chamber walls, leading to changes in critical dimension (CD) and process reproducibility, especially as the number of wafers processed increases.
Innovation Solution
A plasma processing apparatus and method that involves forming a coating film containing Si or SiO on the chamber walls before processing, followed by an aftertreatment to reduce surface roughness and defects, and a metal cleaning step to eliminate residual metal components, ensuring a stable plasma environment and improved etching performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma cleaning is performed wafer by wafer or lot by lot to remove deposited materials, then cleaning effectiveness is improved, but processing throughput decreases
Solution Approach 1:
The patent applies preliminary action by performing plasma cleaning at the beginning of wafer processing (before actual production wafers are processed) to remove deposited materials and stabilize the chamber environment. This preliminary cleaning establishes a consistent baseline state, eliminating the need for repeated cleaning cycles during production, thereby maintaining both cleaning effectiveness and processing throughput.
2Productivity
If the number of wafers processed increases, then productivity improves, but etching performance consistency deteriorates due to residual metal deposits on chamber walls
Solution Approach 1:
The patent performs preliminary plasma cleaning before processing production wafers to remove residual metal deposits on chamber walls. This preliminary action establishes a stable baseline state, preventing deposited materials from affecting etching performance during subsequent wafer processing, thus maintaining consistency even as productivity increases.
Solution Approach 2:
The patent employs feedback by monitoring critical dimension (CD) values during wafer processing and comparing them against target specifications. When CD drift is detected, the system adjusts processing parameters or triggers additional cleaning cycles, creating a closed-loop control system that maintains etching performance consistency throughout production runs.
3Reliability
If plasma cleaning is performed frequently to maintain chamber cleanliness, then etching performance stability is improved, but processing time increases
Solution Approach 1:
The patent performs comprehensive plasma cleaning at the beginning of processing sequences as a preliminary action, establishing a stable chamber state before production begins. This upfront cleaning reduces the frequency of subsequent cleaning interventions, minimizing time loss while maintaining performance stability throughout production runs.
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 stabilizes the plasma process, reduces particle generation, and enhances the reproducibility and yield of the etching process by maintaining consistent etching performance and throughput.
Implementation Method 1
plasma is formed inside the processing chamber to cover the surface of members inside the processing chamber with a coating film containing a component of Si or SiO
Implementation Method 2
the film structure on the surface of a wafer to be processed is etched by using plasma formed by using the process gas
Data Source
AI summary
In a plasma processing apparatus comprising a processing chamber arranged in a vacuum chamber, a sample stage arranged under the processing chamber and having its top surface on which a wafer to be processed is mounted, a vacuum decompression unit for evacuating the interior of the processing chamber to reduce the pressure therein, and introduction holes arranged above said sample stage to admit process gas into the processing chamber, the wafer having its top surface mounted with a film structure and the film structure being etched by using plasma formed by using the process gas, the film structure is constituted by having a resist film or a mask film, a poly-silicon film and an insulation film laminated in this order from top to bottom on a substrate and before the wafer is mounted on the sample stage and the poly-silicon film underlying the mask film is etched, plasma is formed inside the processing chamber to cover the surface of members inside the processing chamber with a coating film containing a component of Si.