Chamber Cleaning Endpoint Detection Using Soak Pressure Changes
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Solution Overview
Problem
Existing substrate processing systems face challenges in accurately determining the end point of a cleaning process to prevent over-etching and extend the lifetime of process chambers and components, while minimizing particle contamination and gas flow disruptions.
Innovation Solution
A method involving a soaking step with pressure measurements within the substrate processing chamber to detect the end point of the cleaning process by monitoring pressure changes due to material layer reactions with the cleaning gas, using components already present in the apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cleaning process is extended to remove all material layers, then particle contamination is reduced, but over-etching damages the process chamber and components
Solution Approach 1:
The system uses real-time pressure monitoring during the soaking step to detect when the material layer has been completely removed. The pressure change signal provides feedback to automatically terminate the cleaning process, preventing over-etching while ensuring complete contamination removal.
2Productivity
If cleaning gas flow rate is increased to improve cleaning efficiency, then material removal speed increases, but chamber pressure stability decreases
Solution Approach 1:
The cleaning process uses periodic cycles of cleaning gas flow followed by soaking steps with closed valves. This periodic action allows high flow rates during cleaning intervals while maintaining pressure stability during soaking intervals when reactions occur and pressure is monitored.
3Measurement precision
If additional end point detection components are installed, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The system uses the existing pressure measurement device already present in the substrate processing apparatus to detect the end point of cleaning. The pressure changes during the soaking step provide self-service detection without requiring additional sensors or measurement equipment.
4Reliability
If the soaking time is extended to ensure complete material removal, then cleaning thoroughness improves, but process duration increases
Solution Approach 1:
Real-time pressure monitoring during the soaking step provides feedback on the completion of material removal. The process terminates automatically when the pressure change signal indicates complete removal, optimizing the soaking time to be long enough for thorough cleaning but short enough to avoid unnecessary delays.
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
Enables reliable end point detection without additional costly components, reducing process duration, and maintaining chamber integrity by preventing over-etching and minimizing contamination.
Implementation Method 1
If a layer of material is present on inner surfaces of the chamber, this material may react with the cleaning gas confined in the chamber during the soaking step
Implementation Method 2
receiving at least two pressure measurements of pressure in the substrate processing chamber while the cleaning gas is contained within the chamber
Data Source
AI summary
A method of determining an end point of a substrate processing chamber cleaning process is disclosed. The method comprises the steps of performing a soaking step comprising containing a cleaning gas within the substrate processing chamber and receiving at least two pressure measurements of pressure in the substrate processing chamber while the cleaning gas is contained within the chamber; and determining whether an end point of the cleaning process has been reached based on the at least two pressure values.