Spatial Plasma Monitoring via Multi-Point Optical Spectroscopy
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Solution Overview
Problem
Existing plasma monitoring systems struggle with reliability and precision in determining the state of plasma within a chamber during semiconductor processing, particularly in real-time applications.
Innovation Solution
A plasma monitoring system with a chamber equipped with an optical window, a substrate stage, a light collecting device comprising a body with through holes and light collectors, and a light analysis device using a spectrometer to map the plasma state based on optical spectra, enabling precise and reliable plasma monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a plasma monitoring system uses optical emission spectroscopy to determine species of particles emitted from plasma, then the energy state of plasma can be monitored, but the measurement precision and reliability of plasma state monitoring is insufficient
Solution Approach 1:
The monitoring system divides the plasma space into multiple measurement zones by positioning multiple light collectors at different locations. Each light collector independently monitors plasma state at its specific position, enabling spatially-resolved plasma characterization. This segmentation approach improves measurement precision by capturing local plasma variations that a single monitoring point would miss.
Solution Approach 2:
The system combines multiple light collectors, each capturing light from different plasma regions, into a unified monitoring system. By merging the signals from multiple collectors and analyzing them collectively, the system achieves both high measurement precision for individual plasma zones and reliable overall plasma state assessment, resolving the contradiction between localized precision and global reliability.
2Measurement precision
If multiple light collectors are used to monitor different positions in plasma, then spatial resolution of plasma state is improved, but the device complexity increases
Solution Approach 1:
Each light collector in the system is designed with multi-functionality, serving as both a light gathering element and a spatial positioning marker. The collectors use identical optical components (lenses, fiber optic cables, spectrometers) that can handle multiple wavelengths and plasma conditions, reducing the need for specialized components for each position and thereby limiting overall device complexity while maintaining high spatial resolution.
3Productivity
If real-time plasma monitoring is implemented, then process control capability is improved, but the system requires complex real-time data acquisition and analysis
Solution Approach 1:
The system implements real-time feedback by continuously monitoring plasma state through multiple light collectors and immediately analyzing the spectral data. The control system receives real-time plasma parameter information and can adjust process conditions accordingly. This feedback mechanism enhances process control capability while the automated analysis algorithms keep the data processing complexity manageable.
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
Enhances the reliability and precision of plasma state determination, allowing for intuitive understanding of chamber conditions and optimizing process parameters such as substrate stage height and temperature control.
Implementation Method 1
a reflection mirror configured to reflect at least some of the lights incident through the through hole
Implementation Method 2
an optical fiber configured to transmit the some of the lights reflected from the reflection mirror
Implementation Method 3
a collimator configured to illuminate the portions of the lights transmitted from the optical fiber toward the optical window
Implementation Method 4
a light analysis device including a spectrometer that is configured to obtain optical spectrum from each of the lights irradiated onto the optical window
Data Source
AI summary
A plasma monitoring system includes a chamber with an interior space, the chamber being configured to perform a semiconductor process on a semiconductor substrate using plasma in the interior space, and the chamber including an optical window, a substrate stage within the chamber to support the semiconductor substrate, a light collecting device on the substrate stage, the light collecting device including a body and light collectors, the body having through holes therethrough, and the light collectors being configured to collect light respectively incident on the through holes from the plasma and to transfer the collected lights onto the optical window, and a light analyzer including a spectrometer that is configured to obtain an optical spectrum from each light irradiated onto the optical window, and to map a state of the plasma from the optical spectrum to correspond to positions of the through holes.