Dual-Spectrometer Wavelength Control for Narrowed-Line Lasers
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Solution Overview
Problem
Semiconductor exposure apparatuses face challenges in maintaining resolution due to chromatic aberrations caused by wide spectral linewidths of light sources, which are not adequately addressed by existing line narrowing modules.
Innovation Solution
A wavelength measurement apparatus and narrowed-line laser apparatus that utilize a first and second spectrometer with different free spectral ranges to accurately measure and control the center wavelength of pulse laser beams, enabling precise wavelength selection and reduction of chromatic aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single spectrometer with a fixed free spectral range is used for wavelength measurement, then the measurement system is simple, but it cannot accurately measure wavelengths across a wide range while maintaining high precision
Solution Approach 1:
The wavelength measurement system is segmented into two distinct spectrometers: a first spectrometer with a first free spectral range for coarse wavelength measurement, and a second spectrometer with a second free spectral range for fine wavelength measurement. This segmentation allows each spectrometer to operate within its optimized range, achieving high measurement precision across a wide wavelength span without requiring a single complex spectrometer
Solution Approach 2:
The patent adds a dimensional aspect to wavelength measurement by introducing multiple spectrometers with different free spectral ranges operating in parallel. The processor combines measurements from both spectrometers, effectively creating a multi-dimensional measurement space that covers both wide ranges and fine resolutions simultaneously
2Manufacturing precision
If the spectral linewidth of the laser beam is narrowed to reduce chromatic aberrations, then the imaging resolution is improved, but the wavelength selection becomes more sensitive and difficult to control
Solution Approach 1:
The processor uses measurements from both the first and second spectrometers to calculate the center wavelength of the pulse laser beam with high precision. This feedback information is then used to control the actuator that adjusts the wavelength selection, enabling accurate wavelength control despite the sensitivity introduced by line narrowing
Solution Approach 2:
The patent replaces simple mechanical wavelength tuning with a precision control system that uses optical feedback from dual spectrometers. The processor calculates the center wavelength based on interference patterns from both spectrometers and uses this information to precisely control the actuator, substituting rough mechanical adjustment with precision optical measurement and control
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
The solution allows for high-resolution imaging by accurately controlling the wavelength of laser beams, thereby improving the manufacturing process of electronic devices by reducing chromatic aberrations and maintaining imaging performance across varying photoresist film thicknesses.
Implementation Method 1
a first spectrometer having a first free spectral range and configured to generate a first measured waveform from an interference pattern produced by a pulse laser beam
Data Source
AI summary
A wavelength measurement apparatus includes a first spectrometer that has a first free spectral range and generates a first measured waveform from an interference pattern produced by a pulse laser beam, a second spectrometer that has a second free spectral range narrower than the first free spectral range and generates a second measured waveform from the interference pattern produced by the pulse laser beam, and a processor that reads data on a first measurement range of the first spectrometer, sets a second measurement range of the second spectrometer based on the data on the first measurement range, reads data on the second measurement range, and calculates a center wavelength of the pulse laser beam based on the data on the first measurement range and the data on the second measurement range.