Plasma View Port Monitoring for Accurate Etch End-Point Detection
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Solution Overview
Problem
Existing substrate processing apparatuses face challenges in accurately measuring plasma conditions due to changes in electron density and reduced transmittance caused by by-products, which affect the precision of etch end-point determination during processes like etching and deposition.
Innovation Solution
A substrate processing apparatus equipped with a view port, reflector, and measurement device that includes units to measure plasma transmittance and electron density, compensating for reduced transmittance and electron density fluctuations, allowing precise measurement of plasma emission intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma is used for substrate processing, then processing capability is improved, but measurement precision deteriorates due to electron density changes and by-product accumulation
Solution Approach 1:
The system implements feedback control by continuously monitoring plasma conditions through optical measurement and automatically adjusting process parameters to compensate for electron density changes and by-product accumulation, thereby maintaining measurement precision throughout the processing operation
Solution Approach 2:
The system changes measurement parameters by selecting specific optical wavelengths and adjusting measurement conditions based on real-time plasma state, allowing accurate measurement across varying electron density conditions and by-product concentrations
2Ease of operation
If view port transmittance is used for measurement, then measurement simplicity is improved, but measurement precision deteriorates due to by-product deposition on view port
Solution Approach 1:
The system uses feedback control to monitor view port transmittance and automatically compensate for by-product deposition effects by adjusting measurement references or triggering cleaning cycles, maintaining measurement accuracy without complex manual intervention
Solution Approach 2:
The system implements self-service through automatic view port cleaning mechanisms that periodically remove by-product deposits, or through self-calibration routines that reference known standards to correct for transmittance changes, eliminating the need for frequent manual maintenance
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 accurate determination of etch end-points by compensating for electron density and transmittance changes, improving the precision of substrate processing methods and semiconductor device manufacturing.
Implementation Method 1
light emitted from the plasma may be measured. For example, plasma emission intensity may be measured
Implementation Method 2
a reflector facing the view port and located on an inner wall of the process chamber
Data Source
AI summary
A substrate processing apparatus includes a process chamber having a process space and a port hole, a view port located within the port hole and coupled to the process chamber, a reflector facing the view port and located on an inner wall of the process chamber, a measurement device connected to the view port and measuring plasma in the process space. The measurement device may include a first measurement unit measuring transmittance of the view port reduced by by-products and a second measurement unit measuring electron density in the plasma.