Semiconductor Chamber Moisture Detection With Narrow Optical Filters
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Solution Overview
Problem
Semiconductor processing tools experience prolonged downtime and increased maintenance costs due to moisture contamination, which is difficult to detect and remove efficiently, especially at low pressures, using existing techniques like mass spectrometry or infrared absorption, leading to lengthy pump-down procedures.
Innovation Solution
A moisture detection module using narrow bandpass optical filters centered at specific wavelengths, such as 309 nm, coupled with photodiodes to detect moisture content by filtering electromagnetic radiation from a plasma source, allowing for efficient and cost-effective moisture monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mass spectrometer or infrared absorption techniques are used to detect moisture, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and isolates the specific spectral region containing the moisture absorption line (309 nm) using a narrow bandpass optical filter. This extraction approach separates the detection of moisture from the need for complex full-spectrum analysis, allowing simple photodiode detection while maintaining measurement precision for the specific target analyte.
Solution Approach 2:
The patent applies local quality by concentrating detection resources on the specific wavelength region where moisture absorbs (309 nm) rather than analyzing the entire spectrum. The narrow bandpass filter (1-10 nm bandwidth) creates a localized detection window that optimizes sensitivity for moisture while simplifying the overall detection system.
2Ease of operation
If broad spectrum detection is used, then ease of operation is improved, but measurement precision deteriorates due to interference from other spectral lines
Solution Approach 1:
The narrow bandpass optical filter extracts only the specific spectral region containing the moisture absorption line at 309 nm, removing interfering spectral lines from other sources (such as nitrogen at 337 nm). This extraction maintains operational simplicity while achieving high measurement precision by eliminating spectral interference.
3Reliability
If pump down procedures are extended to ensure moisture removal, then reliability is improved, but loss of time increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the 309 nm absorption signal during the pump down process. This real-time feedback allows the system to determine when moisture levels have reached acceptable thresholds, enabling reliable moisture control while minimizing unnecessary extended pump down time and reducing overall downtime.
Solution Approach 2:
The moisture detection system performs preliminary assessment of moisture levels before and during pump down procedures. This preliminary action allows for optimized pump down duration by identifying when moisture removal is sufficient, preventing both premature termination (which would compromise reliability) and excessive extension (which would increase downtime).
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 rapid and accurate moisture detection within semiconductor processing tools, reducing downtime and maintenance costs by simplifying the detection process and minimizing the need for extensive pump-down procedures.
Implementation Method 1
an optical bandpass filter configured to be optically coupled to a light source, where a passband is centered at 309 nm
Implementation Method 2
initiating a plasma in the chamber, and passing electromagnetic radiation through a port in the chamber
Implementation Method 3
detecting the filtered electromagnetic radiation with a photodiode
Data Source
AI summary
Embodiments disclosed herein include a moisture detection module. In an embodiment, the moisture detection module comprises an optical bandpass filter configured to be optically coupled to a light source, where a passband is centered at 309 nm. In an embodiment, the moisture detection module further comprises a detector optically coupled to the optical bandpass filter.