Pellicle Condition Monitoring via Infrared Sensor in EUV Lithography
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Solution Overview
Problem
EUV lithographic apparatuses face challenges in detecting pellicle conditions, such as temperature and particle presence, which can lead to substrate damage and reduced throughput due to the lack of effective monitoring and control systems.
Innovation Solution
An apparatus and method utilizing a sensor to measure infrared radiation and temperature profiles of the pellicle, integrated into a lithographic apparatus, allowing for real-time monitoring and control of pellicle conditions, including particle detection and active power control to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pellicle is used in an EUV lithographic apparatus to protect the patterning device, then the patterning device is protected from contamination, but the pellicle itself becomes susceptible to damage from absorbed radiation power and particle impacts
Solution Approach 1:
The system performs preliminary detection of pellicle conditions (temperature, particles) before damage occurs. The sensor continuously monitors the pellicle state and provides early warning signals, enabling preventive action to be taken before the pellicle is damaged, thus maintaining patterning device protection while avoiding pellicle failure
Solution Approach 2:
The system implements feedback control by using a sensor to detect pellicle conditions and providing real-time information about temperature and particle presence. This feedback loop allows the system to adjust operating parameters or alert operators to prevent pellicle damage while maintaining its protective function
2Duration of action of stationary object
If the radiation power is reduced to prevent pellicle damage, then the pellicle lifetime is extended, but the substrate throughput decreases
Solution Approach 1:
By detecting pellicle condition early through temperature and particle monitoring, the system can maintain optimal radiation power levels for extended periods before damage occurs. This preliminary detection allows the system to operate at higher throughput levels safely, only reducing power when actually needed to prevent damage
Solution Approach 2:
The feedback mechanism provides real-time information about pellicle health status, allowing dynamic adjustment of radiation power. The system can maintain high power (high throughput) when the pellicle is healthy and only reduce power when sensors indicate approaching damage thresholds, optimizing both lifetime and productivity
3Measurement precision
If traditional particle detection methods are used, then particle presence can be detected, but the system lacks real-time temperature monitoring and predictive capability for pellicle failure
Solution Approach 1:
The sensor system is designed to perform multiple functions: detecting particles, measuring temperature, and providing predictive information about pellicle failure risk. This multi-functional approach consolidates what would otherwise require separate detection systems, providing comprehensive monitoring without adding significant complexity
Solution Approach 2:
The sensor acts as an intermediary between the pellicle and the control system, translating physical conditions (temperature, particle presence) into actionable information. This intermediary provides a comprehensive view of pellicle state that enables both accurate particle detection and predictive failure analysis
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
Enhances substrate throughput by preventing pellicle damage, allowing for increased power usage while maintaining safety, and reducing the need for additional hardware, enabling immediate feedback on pellicle conditions.
Implementation Method 1
the sensor is configured to measure infrared radiation (IR) associated with the pellicle
Implementation Method 2
The sensor may be configured to measure an IR emission spectrum associated with the pellicle
Data Source
AI summary
An apparatus for determining a condition associated with a pellicle for use in a lithographic apparatus, the apparatus including a sensor, wherein the sensor is configured to measure a property associated with the pellicle, the property being indicative of the pellicle condition.