In-situ Optical Chamber Sensor with Reflector for Quantitative OES
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Solution Overview
Problem
Current optical emission spectroscopy (OES) systems in semiconductor manufacturing provide only qualitative measurements, unable to perform precise quantitative analysis of processing parameters such as etch rate, limiting the ability to ensure uniform processing across substrates.
Innovation Solution
An optical sensor system with a reflector surface exposed to the processing environment, allowing for quantitative measurements by using a reference signal to account for optical path losses and correlating electromagnetic radiation absorption with material composition and thickness, enabling in-situ monitoring of chamber conditions and processing parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If OES is implemented with a window to prevent deposition, then qualitative analysis capability is improved, but quantitative measurement precision deteriorates due to inability to account for optical path losses
Solution Approach 1:
A reflector is introduced as an intermediary element within the chamber that reflects electromagnetic radiation back through the optical path. This allows the system to measure both the forward and return paths, enabling calculation and compensation of optical losses that occur during substrate processing. The reflector serves as a mediator that provides reference information about the optical path conditions without interfering with the primary measurement objective.
2Stability of the object's composition
If the optical path is kept closed to prevent deposition, then measurement stability is improved, but the ability to monitor chamber surface conditions deteriorates
Solution Approach 1:
The reflector acts as an intermediary that exposes a controlled surface to the chamber environment while maintaining the optical path's closed structure. This surface can be monitored for deposition and condition changes, providing information about chamber surface conditions without requiring the optical path itself to be open or vulnerable to contamination.
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, quantitative measurement of plasma emission spectra, allowing for precise determination of processing parameters and chamber uniformity, and detecting abnormalities, thereby improving process control and consistency across different chambers.
Implementation Method 1
reflecting the electromagnetic radiation back along the optical path with the reflector
Implementation Method 2
sensing electromagnetic radiation emitted in the processing chamber that travels along the optical path with the sensor
Data Source
AI summary
Embodiments disclosed herein include optical sensor systems and methods of using such systems. In an embodiment, the optical sensor system comprises a housing and an optical path through the housing. In an embodiment, the optical path comprises a first end and a second end. In an embodiment a reflector is at the first end of the optical path, and a lens is between the reflector and the second end of the optical path. In an embodiment, the optical sensor further comprises an opening through the housing between the lens and the reflector.