Line Sensor Deterioration Evaluation for Semiconductor Exposure
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Solution Overview
Problem
Line sensors in semiconductor exposure apparatuses deteriorate over time, leading to decreased sensor sensitivity and inaccurate measurements, necessitating a method to evaluate their deterioration state for timely replacement.
Innovation Solution
A deterioration evaluation method using a line sensor that detects interference fringes from pulse laser light, calculates an evaluation value based on light intensity, and determines the sensor's state by integrating count values or light amount integration values, allowing for targeted replacement of deteriorated sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a line sensor is used to detect interference fringes of pulse laser light, then wavelength and spectral line width measurements can be performed, but the sensor deteriorates over time leading to decreased sensitivity and inaccurate measurements
Solution Approach 1:
The patent applies preliminary action by evaluating the deterioration state of the line sensor before it completely fails. The processor calculates deterioration evaluation values based on signal values from sensor channels and compares them against threshold values to determine deterioration states in advance, allowing for timely replacement before measurement accuracy is severely compromised.
Solution Approach 2:
The patent implements feedback by continuously monitoring the signal values from the line sensor and calculating deterioration evaluation values that provide information about the sensor's current state. This feedback mechanism allows the system to track sensor performance degradation over time and trigger replacement when thresholds are exceeded.
2Measurement precision
If the line sensor is replaced before deterioration, then measurement accuracy is maintained, but replacement frequency increases leading to economic loss
Solution Approach 1:
The patent enables preliminary replacement decisions by evaluating sensor deterioration states before complete failure occurs. The deterioration evaluation value calculation allows operators to determine the optimal replacement timing, replacing sensors only when necessary based on actual deterioration conditions rather than using fixed replacement cycles.
Solution Approach 2:
The patent changes the parameter for replacement decision from fixed time-based or usage-based cycles to a dynamic threshold-based system. The deterioration evaluation value is compared against threshold values that can be adjusted, allowing optimization of replacement timing to balance measurement accuracy maintenance with economic efficiency.
3Measurement precision
If all sensor channels are replaced uniformly, then measurement accuracy is restored, but replacement cost increases without targeting actual deteriorated channels
Solution Approach 1:
The patent segments the line sensor into multiple sensor channels, each with its own deterioration evaluation. The processor calculates deterioration evaluation values for individual sensor channels or groups of channels, allowing targeted replacement of only the deteriorated portions rather than replacing the entire sensor array uniformly.
Solution Approach 2:
The patent applies local quality by evaluating and managing the deterioration state of specific sensor channels or groups of channels individually. The system identifies which specific channels have exceeded deterioration thresholds and targets replacement to those local areas, optimizing resource allocation and reducing unnecessary replacement costs.
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 the detection of specific sensor channel deterioration, facilitating timely replacement and maintaining accurate wavelength and spectral line width measurements, thereby improving measurement precision and reducing economic losses.
Implementation Method 1
detecting an interference fringe of pulse laser light using the line sensor
Implementation Method 2
calculating, based on a signal value obtained from each of a plurality of sensor channels included in a sensor channel range being at least a part of the line sensor in accordance with light intensity of the interference fringe
Data Source
AI summary
A deterioration evaluation method of a line sensor includes detecting an interference fringe of pulse laser light using the line sensor; calculating, based on a signal value obtained from each of a plurality of sensor channels included in a sensor channel range being at least a part of the line sensor in accordance with light intensity of the interference fringe, an evaluation value which is an index of deterioration for each of the sensor channels or each group of the sensor channels, and storing the evaluation value in a storage device; and determining a deterioration state of the line sensor based on the evaluation value.