Optical Detection of Dynamic Gas Lock Membrane Rupture in Lithography
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Solution Overview
Problem
Current methods for detecting ruptures in dynamic gas lock (DGL) membranes in lithographic apparatuses are unreliable, especially when the apparatus is idle or being serviced, and rely on costly EUV light-based monitoring, which limits detection to operational states, leading to potential wafer damage and increased machine downtime.
Innovation Solution
The implementation of optical detection methods using a measurement beam and reflection collection optics to continuously monitor DGL membranes for ruptures, allowing for timely replacement and preventing service disruptions, along with the use of infrared cameras for independent monitoring during any apparatus state, including service and idle times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure measurement methods are used to detect membrane rupture, then detection can be performed during operation, but the detection is unreliable and cannot detect ruptures during idle or service states
Solution Approach 1:
The patent replaces mechanical pressure measurement methods with optical detection methods. An optical sensor detects light transmission through the membrane to determine its integrity state, eliminating the need for mechanical pressure measurements and enabling reliable detection across all apparatus states including idle and service conditions.
Solution Approach 2:
The optical detection system serves multiple functions: it detects membrane rupture during operation, during idle states, and during service. The same optical sensor and light source configuration can identify both intact and ruptured membrane states, providing universal detection capability across different operational conditions.
2Reliability
If intensity monitoring at the wafer plane is used to detect membrane rupture, then detection can occur during operation, but frequent calibration measurements are required which are complex and degrade utilization
Solution Approach 1:
The optical detection system uses a light source and sensor positioned to automatically detect membrane integrity without requiring external calibration or intervention. The system continuously monitors light transmission and self-adjusts to maintain accurate detection, eliminating the need for frequent manual calibration measurements and preserving machine utilization.
3Measurement precision
If EUV light-based monitoring is used for end-of-life detection, then monitoring can be performed, but it requires expensive machine time and limits detection to operational states only
Solution Approach 1:
The patent changes the detection parameter from EUV light transmission to visible or infrared light transmission. This parameter change allows detection to occur with non-EUV light sources, enabling monitoring during idle and service states without consuming expensive EUV machine time, while maintaining the ability to detect membrane degradation and rupture.
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 continuous, reliable detection of DGL membrane ruptures and end-of-life monitoring, reducing the risk of wafer damage and machine downtime, while eliminating the need for expensive EUV light-based diagnostics, thus improving operational efficiency and reducing costs.
Implementation Method 1
determining whether any radiation from the measurement beam is reflected from the dynamic gas lock membrane by using reflection collection optics
Implementation Method 2
the use of infrared cameras for independent monitoring during any apparatus state
Data Source
AI summary
Embodiments herein describe methods, devices, and systems for rupture detection and end-of-life monitoring of dynamic gas lock (DGL) membranes and pupil facet mirrors in lithographic apparatuses. A method for detecting rupture of a dynamic gas lock membrane in a lithographic apparatus includes illuminating the dynamic gas lock membrane with a measurement beam using a radiation source, in which the dynamic gas lock membrane is arranged between a wafer and projection optics of the lithography apparatus, and determining whether any radiation from the measurement beam is reflected from the dynamic gas lock membrane by using reflection collection optics, in which the reflection collection optics are arranged above the dynamic gas lock membrane. A rupture in the dynamic gas lock membrane is detected if no radiation is reflected from the dynamic gas lock membrane. If radiation is reflected from the dynamic gas lock membrane, the dynamic gas lock membrane is not ruptured.