Reflective Radical Density Scanning in Plasma Process Chambers
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Solution Overview
Problem
Existing radical spatial density measurement methods in plasma chambers are limited by minimum pulse periods of several seconds due to transient gas distribution stabilization, leading to poor spatial resolution and requiring process interruption for installation, which is not suitable for mass production.
Innovation Solution
An apparatus and method using a single port external light source and a moving wall within the process chamber to measure radical spatial density via reflective optical absorption spectroscopy, allowing continuous scanning without process interruption and improving spatial resolution through light path reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single port external light source with moving wall is used for measurement, then spatial resolution is improved and continuous measurement is enabled, but device complexity increases
Solution Approach 1:
The patent employs a moving wall that can be dynamically positioned within the process chamber to different locations for measurement. This dynamic component allows the system to scan multiple spatial positions sequentially, achieving high spatial resolution without requiring multiple fixed measurement ports or complex multi-point simultaneous measurement systems. The moving wall transforms a potentially complex multi-point measurement device into a simpler sequential measurement system.
Solution Approach 2:
The patent introduces a moving wall as an intermediary element between the external light source and the plasma chamber interior. This moving wall serves as a reflector that can be positioned at different locations to measure radical density at various spatial points. The intermediary moving wall enables the external light source to probe different regions of the chamber without requiring the light source itself to be moved or multiplied, thus improving spatial resolution while controlling device complexity.
2Measurement precision
If gas distribution stabilization time is waited for measurement, then measurement accuracy is improved, but productivity decreases due to process interruption
Solution Approach 1:
The patent performs measurement actions during the transient phase of gas distribution, rather than waiting for complete stabilization. By measuring during the transient phase itself and using appropriate data processing methods, the system obtains useful measurement information without requiring the full stabilization time, thus maintaining measurement accuracy while improving productivity by eliminating process interruptions.
Solution Approach 2:
The patent enables continuous measurement during the plasma etching process by using a moving wall that can quickly position and measure at different locations without requiring the process to stop. The external light source continuously probes the plasma through the moving wall's reflection, maintaining continuous useful measurement action throughout the process rather than interrupting for discrete measurements, thereby preserving both accuracy and productivity.
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 continuous measurement of radical spatial density with enhanced spatial resolution and facility operation without process interruption, suitable for mass-produced plasma etching processes.
Implementation Method 1
a collimator disposed in the viewport of the process chamber and configured to transmit light received from the light source to the moving wall and receive light reflected from the moving wall
Implementation Method 2
a spectrometer configured to receive the reflected light from the collimator, and measure radical spatial density based on analyzing an absorption amount of a spectrum of the received light
Data Source
AI summary
Provided is an apparatus configured to measure radical spatial density distribution including a process chamber including a viewport, a driving device configured to move a moving wall inside the process chamber, a light source configured to generate light, a collimator disposed in the viewport of the process chamber and configured to transmit light received from the light source to the moving wall and receive light reflected from the moving wall, and a spectrometer configured to receive the reflected light from the collimator, and measure radical spatial density based on analyzing an absorption amount of a spectrum of the received light.