Lithographic Apparatus Maintenance Scheduling to Reduce C-Time
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Solution Overview
Problem
Maintenance actions in lithographic apparatuses cause significant productivity loss due to the need to ramp down and ramp up production, leading to increased C-time, which is not optimally managed by existing strategies.
Innovation Solution
A method to optimize maintenance by determining the number of layers to ramp down and scheduling maintenance actions based on productivity and error metric data, using conversion models and machine learning to predict non-correctable errors, thereby minimizing C-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If maintenance actions are performed on the lithographic apparatus, then component reliability is improved, but productivity is reduced due to ramp-down and ramp-up time
Solution Approach 1:
The patent applies preliminary action by performing maintenance actions during periods when productivity impact is minimized. The system predicts optimal maintenance timing based on component degradation trends and schedules maintenance during ramp-down phases or when fewer layers are being produced, thereby reducing the productivity loss associated with maintenance interruptions.
Solution Approach 2:
The patent implements dynamics by making the maintenance schedule adaptive rather than fixed. The system continuously monitors component performance and adjusts maintenance timing dynamically based on actual degradation rates, allowing flexibility in scheduling maintenance actions to minimize productivity impact while ensuring component reliability.
2Manufacturing precision
If more layers are ramped down before maintenance, then maintenance impact on overlay accuracy is reduced, but productivity loss increases
Solution Approach 1:
The patent applies parameter changes by optimizing the number of layers ramped down as a variable parameter. The system calculates the optimal number of layers to ramp down based on predicted maintenance impact, balancing the need to minimize overlay accuracy degradation with the need to limit productivity loss. This dynamic parameter adjustment allows flexible optimization of the ramp-down strategy.
3Reliability
If maintenance frequency is increased, then component reliability is improved, but total maintenance time and productivity loss increase
Solution Approach 1:
The patent implements feedback by using real-time monitoring of component performance and degradation trends to determine optimal maintenance timing. The system continuously collects data on component condition and adjusts maintenance scheduling based on actual degradation rates, preventing both premature maintenance (which wastes time) and delayed maintenance (which compromises reliability).
Data Source
AI summary
A method of optimizing maintenance of a lithographic apparatus. The method including obtaining productivity data relating to a productivity of a lithographic apparatus and error metric data relating to the effect of a maintenance action on exposure performance. The productivity data and error metric data is used to determine such that a loss of productivity metric is reduced or minimized, one or both of: a number of layers to ramp down in production of integrated circuits prior to the maintenance action on the lithographic apparatus, the layers being lithographically exposed on each of a plurality of substrates using the lithographic apparatus; and/or a maintenance schedule metric relating to the frequency of performance of the maintenance action.