Plasma Chamber Optical Layout for Active Species Density Sensing
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Solution Overview
Problem
Existing plasma processing technologies face challenges in achieving high integration density and accurate measurement of active species gas density during semiconductor manufacturing, which affects processing performance and product reliability.
Innovation Solution
A plasma processing apparatus and method that includes a housing with a viewing window, reflector, optical source unit, and spectrometer to irradiate and reflect light, allowing for the determination of active species gas density by analyzing incident and reflected light intensities, thereby improving integration density and measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plasma processing apparatus is used for semiconductor manufacturing, then processing performance is improved, but measurement accuracy of active species gas density deteriorates
Solution Approach 1:
The patent introduces an optical intermediary system consisting of a viewing window, optical source, reflector, and spectrometer to indirectly measure active species gas density. The optical source emits light through the viewing window into the plasma region, where the active species gas absorbs specific wavelengths. The reflected light from the reflector carries absorption information that is analyzed by the spectrometer to determine gas density, thereby achieving accurate measurement without direct interference with the plasma processing.
Solution Approach 2:
The patent replaces direct physical or mechanical measurement methods with an optical measurement system. Instead of using probes or sensors that would physically interact with the plasma and potentially disrupt processing, the system uses non-contact optical absorption spectroscopy to measure active species gas density, maintaining both processing performance and measurement accuracy.
2Productivity
If integration density is increased, then manufacturing efficiency is improved, but device complexity increases
Solution Approach 1:
The optical source unit serves multiple functions: it provides light for absorption spectroscopy measurement, enables monitoring of active species gas density in real-time, and allows for process optimization. The reflector both directs light through the plasma region and enables the optical path to be compactly arranged within the apparatus. This multi-functionality reduces the need for separate dedicated components, thereby managing device complexity while supporting high integration density.
Solution Approach 2:
The patent arranges the optical components in a compact configuration using a folded optical path with the reflector positioned at an angle. This allows the measurement system to be integrated into the existing plasma processing apparatus without requiring additional space, thereby supporting high integration density while maintaining functional complexity only where necessary.
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 integration density and enables precise control of active species gas density, leading to improved processing performance and reliability in semiconductor manufacturing.
Implementation Method 1
an optical source unit covering the viewing window, including a collimator and configured to generate incident light irradiating the active species region at a wavelength band ranging from about 900 nm to about 1800 nm through the viewing window
Implementation Method 2
a reflector disposed on an interior of the second side wall, laterally aligned with the viewing window and configured to reflect a portion of the incident light irradiating the active species region to generate reflected light
Implementation Method 3
a spectrometer configured to receive the reflected light from the reflector through the viewing window and the optical source unit, and a controller configured to calculate density of the active species gas within the active species region in relation to a first intensity of the incident light and a second intensity of the reflected light
Data Source
AI summary
A plasma processing apparatus includes; a housing including a first side wall and a second side wall, wherein the housing defines a processing region in which plasma is generated, an optical source unit disposed on the first side wall in alignment with the viewing window, wherein the optical source unit is configured to irradiate the processing region with incident light through the viewing window, a reflector disposed on the second side wall of the housing, wherein the reflector reflects a portion of the incident light irradiating the processing region to generate reflected light, a spectrometer configured to receive the reflected light from the reflector through the viewing window and the optical source unit and a controller configured to determine density of the active species gas within the processing region in relation to the incident light and the reflected light.