Optical Spectrum Monitoring for Single-Wafer Wet Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current technologies in single wafer processing lack a comprehensive monitoring system to track the status of substrate processing, including the state of the processing solution and the substrate surface, beyond measuring specific components or film thickness.
Innovation Solution
A substrate processing status monitoring device that includes a light projecting unit, a light receiving unit, a photometry unit for simultaneous wavelength dispersion and intensity measurement, and an operation unit that generates an optical spectrum by comparing it with a reference spectrum or past spectra to detect changes in substrate processing status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only specific components in the processing solution are measured (e.g., H2O abundance in IPA), then measurement precision for that specific component is improved, but comprehensive monitoring of the entire substrate processing status is lost
Solution Approach 1:
The optical spectrum monitoring system is designed to perform multiple functions simultaneously: it measures specific component concentrations (e.g., H2O in IPA) while also monitoring overall processing status, film thickness changes, and surface state. This universal monitoring approach replaces multiple specialized measurement systems with one comprehensive optical system that captures all processing information through spectral analysis.
Solution Approach 2:
The system transitions from one-dimensional measurement (single wavelength absorbance for specific components) to multi-dimensional measurement (full optical spectrum across multiple wavelengths). By analyzing the entire spectral range, the system simultaneously extracts information about different processing parameters, including component concentrations, film thickness, and surface characteristics, thereby preventing information loss.
2Measurement precision
If film thickness is measured during dry etching using optical spectrum, then etching endpoint detection is improved, but monitoring of wet processing status is not achieved
Solution Approach 1:
The optical monitoring system is configured to work with both wet and dry processing methods. During wet processing, it measures the optical spectrum of light passing through the processing solution to monitor solution state and substrate surface condition. During dry etching, it measures reflected light spectrum to detect film thickness and etching endpoint. This universal design allows the same system to adapt to different processing types without requiring separate measurement systems.
Solution Approach 2:
The system dynamically adjusts its measurement mode based on the processing type. For wet processing, it optimizes for transmission spectroscopy to monitor solution properties; for dry etching, it switches to reflection spectroscopy for film thickness measurement. This dynamic adaptability ensures high versatility across different substrate processing methods while maintaining measurement precision for each specific application.
3Loss of information
If comprehensive optical spectrum monitoring is implemented, then overall processing status detection is improved, but device complexity increases compared to simple component measurement
Solution Approach 1:
The system introduces an optical spectrum as an intermediary that carries comprehensive processing information. Instead of using multiple separate sensors for different parameters, a single optical measurement captures the full spectrum, which then serves as a mediator containing all necessary information about processing status, component concentrations, and surface conditions. This intermediary approach simplifies the physical device while maintaining comprehensive monitoring capability.
Solution Approach 2:
The system extracts specific processing information from the comprehensive optical spectrum through spectral analysis. Rather than requiring separate measurement systems for each parameter, the system takes out individual pieces of information (component concentration, film thickness, surface state) from the full spectral data by analyzing specific wavelength regions and spectral features. This extraction approach reduces device complexity while preserving comprehensive monitoring capability.
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 comprehensive monitoring of substrate processing status, allowing for real-time detection of processing abnormalities and condition feedback, thereby improving processing control and efficiency.
Implementation Method 1
a light receiving unit that receives light that has passed through the processing solution
Implementation Method 2
a photometry unit that simultaneously disperses light received by the light receiving unit into a plurality of wavelengths and simultaneously measures light intensities of the plurality of wavelengths
Implementation Method 3
generating an optical spectrum from the light intensities of the plurality of wavelengths measured by the photometry unit
Data Source
AI summary
A substrate processing status monitoring device (20) for monitoring a status of substrate processing performed by supplying a processing solution (S) onto a substrate (W) that is rotating, the substrate processing status monitoring device (20) including a light projecting unit (22) that irradiates the substrate with light, a light receiving unit (22) that receives light that has passed through the processing solution, a photometry unit (23) that simultaneously disperses light received by the light receiving unit into a plurality of wavelengths and simultaneously measures light intensities of the plurality of wavelengths, and an operation unit (24) that detects a change in the status of the substrate processing by generating an optical spectrum from the light intensities of the plurality of wavelengths measured by the photometry unit and comparing the optical spectrum with a reference spectrum or the optical spectrum of past previously generated during the substrate processing.