Microlithography Optical Path Acoustic Monitoring for Pattern Errors
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Solution Overview
Problem
High-precision pattern generators and inspection devices are susceptible to acoustic disturbances that bypass mechanical vibration isolation, causing systematic deviations in printed patterns, which existing sensors fail to detect accurately.
Innovation Solution
Implementing an acoustic sensor near the optical path to record and associate acoustic signals with pattern positions, enabling monitoring of interaction quality based on these signals to identify and map potential errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical vibration isolation is used to protect high-precision pattern generators, then manufacturing precision is improved, but acoustic disturbances can still bypass the isolation and cause systematic deviations
Solution Approach 1:
An acoustic sensor is introduced as an intermediary detection device between the acoustic environment and the pattern generator. The sensor detects acoustic disturbances that bypass mechanical isolation, allowing these harmful factors to be identified and addressed without compromising the mechanical vibration isolation already in place.
Solution Approach 2:
The patent replaces mechanical vibration sensing with acoustic field sensing. Instead of relying solely on mechanical sensors to detect vibrations, an acoustic sensor is used to detect acoustic disturbances that mechanically isolated systems cannot block, providing a complementary detection approach.
2Measurement precision
If traditional mechanical sensors are used to detect vibrations, then mechanical movement is measured, but acoustic disturbances that bypass isolation remain undetected
Solution Approach 1:
The acoustic sensor serves as an intermediary detection mechanism that complements traditional mechanical sensors. It detects acoustic disturbances that mechanical sensors cannot perceive, thereby improving the reliability of error detection without compromising measurement precision.
Solution Approach 2:
The patent changes the detection parameter from mechanical movement to acoustic field disturbances. By measuring acoustic parameters (sound pressure, frequency) instead of or in addition to mechanical parameters, the system can detect disturbances that bypass mechanical isolation and improve overall detection reliability.
3Reliability
If acoustic sensors are added to detect disturbances, then quality monitoring is improved, but device complexity increases
Solution Approach 1:
The acoustic sensor system is designed to serve multiple functions: detecting acoustic disturbances, mapping their spatial distribution, and providing feedback for quality monitoring. This multi-functionality improves reliability without proportionally increasing complexity, as a single sensor type performs multiple diagnostic roles.
Solution Approach 2:
The system creates an acoustic field copy or representation through the sensor, allowing virtual analysis of disturbances without physically interfering with the pattern generation process. This copying approach enables monitoring while maintaining system simplicity.
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
Detects and maps acoustic disturbances that affect sensitive components, allowing for precise identification and correction of errors such as mura, enhancing pattern quality and enabling predictive maintenance.
Implementation Method 1
Acoustic signals are recorded in vicinity of the optical path during the interaction
Data Source
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Figure 2A~2B
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AI summary
A method for quality monitoring in microlithography devices comprises interacting (S10) with a two-dimensional pattern on a target by exposing the target for electromagnetic radiation. The exposing is performed using optical components defining an optical path. Acoustic signals are recorded (S11) in vicinity of the optical path during the interaction. The recorded acoustic signals are associated (S20) to positions of the two-dimensional pattern where the interaction with the pattern was performed when respective acoustic signals were recorded. A quality of the interaction with the two-dimensional pattern is monitored (S30) based on the associated acoustic signals and pattern positions. A microlithography device monitorable by the method is also disclosed.