In-situ OES Calibrator Using Reference Light Source
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Solution Overview
Problem
Current optical emission spectroscopy (OES) calibration methods require disassembly from the plasma chamber, leading to prolonged calibration times and potential contamination, as they necessitate transferring the OES to a separate calibration apparatus.
Innovation Solution
A calibrator integrated with the plasma chamber, featuring a detachable cover with a reference light source, mirror, diffuser, and controller, allows for in-situ calibration by comparing the spectrum of a reference light with actual light during plasma processes, eliminating the need for OES disassembly and transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the OES is disassembled from the plasma chamber for calibration, then the calibration can be performed with a reference light source, but the calibration time becomes long and the OES may be contaminated during transfer
Solution Approach 1:
The patent combines the reference light source and calibration components directly into the plasma chamber ceiling, merging the calibration function with the existing plasma processing environment. This eliminates the need to disassemble and transfer the OES to a separate calibration apparatus, thereby reducing calibration time while maintaining calibration accuracy through in-situ spectral comparison.
Solution Approach 2:
The patent introduces a diffuser as an intermediary component between the reference light source and the OES. The diffuser uniformizes the reference light before it reaches the OES, ensuring accurate calibration without requiring physical transfer of the OES, thus solving both the time loss and contamination issues while maintaining measurement precision.
2Measurement precision
If the OES is disassembled from the plasma chamber for calibration, then the calibration can be performed, but the OES may be contaminated during the transfer
Solution Approach 1:
The patent merges the calibration function into the plasma chamber itself by installing the reference light source and necessary optical components (mirror, diffuser) directly in the chamber ceiling. This integration allows calibration to be performed in-situ without disassembling or transferring the OES, thereby completely eliminating the contamination risk associated with physical transfer while maintaining calibration accuracy.
Solution Approach 2:
The plasma chamber is designed to perform its own calibration function by incorporating the reference light source and calibration optics within its structure. The chamber becomes self-sufficient for calibration purposes, eliminating the need for external calibration apparatus and the associated contamination risks of transferring the OES between different environments.
3Productivity
If the reference light is irradiated directly to the OES, then the calibration can be performed, but the light path may not be properly controlled
Solution Approach 1:
The patent segments the optical path into distinct functional zones: a reference light source region, a mirror for directional reflection, a diffuser for uniformization, and the OES detection region. This segmentation allows each component to perform its specific function efficiently, controlling the light path without excessive complexity while maintaining calibration efficiency through optimized optical design.
Solution Approach 2:
The patent uses a mirror and diffuser as intermediary components to control the light path between the reference light source and the OES. The mirror directs the light at a 45-degree angle, and the diffuser uniformizes it before reaching the OES. These intermediaries provide precise optical path control without requiring complex mechanical adjustments, balancing productivity with manageable device complexity.
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
This solution significantly reduces calibration time and prevents contamination by enabling OES calibration within the plasma chamber, ensuring accurate and efficient plasma state diagnosis without disassembling the OES.
Implementation Method 1
a reference light source configured to irradiate a reference light to the OES through the plasma chamber
Implementation Method 2
a mirror slanted with respect to a vertical direction, the mirror configured to reflect the reference light incident to the plasma chamber in the vertical direction toward a viewport
Implementation Method 3
a diffuser configured to diffuse the reference light reflected from the mirror
Implementation Method 4
a collimator configured to induce the reference light diffused by the diffuser in a horizontal direction
Implementation Method 5
a lens configured to concentrate the reference light diffused by the diffuser
Implementation Method 6
a controller configured to calibrate the OES by comparing a spectrum of the reference light incident to the OES with a spectrum of an actual light incident to the OES during a plasma process
Data Source
AI summary
A calibrator of an OES may include a cover, a reference light source and a controller. The cover may be detachably combined with a ceiling of a plasma chamber of a plasma processing apparatus. The reference light source may be installed at the cover to irradiate a reference light to the OES through an inner space of the plasma chamber. The controller may compare a spectrum of the reference light inputted into the OES with a spectrum of an actual light inputted into the OES during a plasma process in the plasma chamber to calibrate the OES. Thus, the OES may be calibrated without disassembling of the OES from the plasma chamber to decrease a time for calibrating the OES.