Lithography Optical Component Travel Path Abnormality Localization
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Solution Overview
Problem
Lithography apparatuses face downtime due to abnormalities in the travel path of optical components, such as particles in air gaps or coating faults, which limit the usable movement range and require rapid detection to minimize financial losses.
Innovation Solution
A method involving moving the optical component in at least one degree of freedom and detecting movement or force in another degree of freedom to localize abnormalities, allowing for rapid identification of issues like particles, coating faults, or misalignment by observing different degrees of freedom, thereby reducing outage times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical delimitation with end stop is used to define travel path, then travel path limitation is achieved, but particles in air gap cause premature contact and reduce usable movement range
Solution Approach 1:
The patent performs preliminary detection of abnormalities (particles, coating faults, misalignment) in the air gap before they cause premature contact and travel path restriction. By detecting these issues in advance through force measurements in a second degree of freedom during movement in a first degree of freedom, the system can identify and address problems before they lead to downtime, thus resolving the contradiction between maintaining reliable travel path limitation and avoiding time loss from outages
Solution Approach 2:
The patent implements a feedback mechanism where force sensors continuously monitor the force acting on the optical component in a second degree of freedom during movement in a first degree of freedom. This feedback allows real-time detection of abnormalities such as particles or coating faults that increase force expenditure, enabling the system to identify travel path restrictions before they cause premature contact and downtime
2Length of moving object
If full travel path is used with minimum force expenditure, then movement range is maximized, but particles or coating faults cause premature contact and limit travel path
Solution Approach 1:
The system performs preliminary detection of abnormalities (particles, coating faults, misalignment) by monitoring force in a second degree of freedom before these issues cause premature contact. This allows the full travel path to be utilized safely by identifying and addressing potential problems in advance, thus maximizing movement range while maintaining contact prevention
Solution Approach 2:
The patent uses continuous force feedback in a second degree of freedom during movement in a first degree of freedom to detect abnormalities that would limit travel path. This feedback mechanism enables real-time monitoring to ensure the full travel path can be used without premature contact, resolving the contradiction between maximizing travel path length and ensuring reliable contact prevention
3Loss of time
If abnormality detection is performed rapidly, then outage time is reduced, but complex measurement across multiple degrees of freedom is required
Solution Approach 1:
The patent uses force in a second degree of freedom as an intermediary parameter to detect abnormalities related to movement in a first degree of freedom. Instead of directly monitoring the first degree of freedom for particles or coating faults, the system measures force in the perpendicular second degree of freedom, which responds to these abnormalities. This intermediary measurement approach enables rapid detection without requiring complex direct observation systems
Solution Approach 2:
The patent replaces complex direct detection methods with force measurements. By using force sensors to detect abnormalities (particles, coating faults, misalignment) through their mechanical effect on the optical component, the system achieves rapid detection without requiring complex optical or imaging systems, thus reducing detection time while managing measurement system complexity
Data Source
Figure 1A
Figure 1B
Figure 2~2A
AI summary
What is disclosed is a method for localizing an abnormality (500) in a travel path (x, y) of an optical component (202) in or for a lithography apparatus (100A, 100B) comprising the following steps: a) moving the optical component (202) in at least one first degree of freedom (Fx, Fy), b) detecting a movement (Rz) of the optical component (202) and/or a force (Mz) acting on the optical component (202) in at least one second degree of freedom (FRz) and c) localizing the abnormality (500) as a function of the movement (Rz) detected in step b) and/or the force (Mz) detected in step b).