Lithographic Apparatus Stage Coordination for Throughput
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Solution Overview
Problem
Existing lithographic apparatuses face challenges in improving throughput, imaging quality, yield, and uptime due to complex operations such as stage swapping and substrate exchange, which are time-consuming and do not directly contribute to image quality.
Innovation Solution
A method and apparatus that includes a projection system for patterning a substrate, multiple stages for supporting substrates, and a control system that manages the positions of these stages. The method involves starting a pre-exposure scrum sweep operation after initiating a substrate exchange operation, allowing the third stage with a sensor or cleaning device to move away from under the projection system while the second stage moves into position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If stage swapping and substrate exchange operations are performed sequentially, then operational complexity is reduced, but throughput and productivity decrease
Solution Approach 1:
The patent applies preliminary action by performing the scrum sweep operation in advance before the substrate exchange operation. The third stage moves to the scrum sweep position and performs cleaning or sensing operations while the first and second stages are still in their initial positions, preparing the system for the subsequent substrate exchange without delaying the main exposure process.
Solution Approach 2:
The patent ensures continuity of useful action by overlapping the scrum sweep operation with the substrate exchange operation. While the third stage performs cleaning or sensing, the first stage simultaneously exchanges substrates, and the second stage prepares for exposure. This parallel execution eliminates idle time and maintains continuous productive activity across all stages.
2Manufacturing precision
If the third stage performs sensing and cleaning operations during substrate exchange, then imaging quality and yield improve, but operation time increases
Solution Approach 1:
The scrum sweep operation is performed as a preliminary action before the substrate exchange completes. The third stage moves to the scrum sweep position and executes cleaning or sensing operations on the immersion liquid or stage surfaces in advance, ensuring that these quality-critical operations are completed before the substrate is exposed, thereby guaranteeing imaging quality without extending the overall exposure cycle time.
Solution Approach 2:
The patent implements continuity of useful action by executing the scrum sweep operation in parallel with the substrate exchange operation. The third stage performs cleaning or sensing while the first stage exchanges substrates, meaning that the time required for scrum sweep does not add to the total operation time. Both operations proceed simultaneously, maintaining continuous productive activity and eliminating sequential delays.
3Productivity
If multiple stages operate simultaneously, then productivity increases, but coordination complexity and potential interference increase
Solution Approach 1:
The patent applies segmentation by dividing the lithographic apparatus into three independently controllable stages, each with distinct functions and positions. The first stage handles substrate exchange, the second stage performs exposure, and the third stage executes scrum sweep operations. This spatial and functional segmentation allows simultaneous operation of multiple stages without interference, as each stage operates in its own designated zone with independent motion control.
Solution Approach 2:
The patent uses a centralized control system as an intermediary to coordinate the simultaneous operations of multiple stages. The control system manages the timing, positioning, and motion of the first, second, and third stages, ensuring that they operate in parallel without collision or interference. This intermediary coordination enables high productivity through parallel processing while maintaining system stability and preventing operational conflicts.
Data Source
AI summary
A method of operating a lithographic apparatus that comprises: a projection system configured to provide exposure radiation for patterning a substrate underneath the projection system; a first stage configured to support a first substrate; a second stage configured to support a second substrate; and a third stage accommodating a component that includes at least one of a sensor and a cleaning device; wherein the method comprises starting a pre-exposure scrum sweep operation after starting a substrate exchange operation; wherein during the pre-exposure scrum sweep operation, the third stage moves away from underneath the projection system while the second stage moves to underneath the projection system; wherein during the substrate exchange operation, the first substrate is unloaded from the first stage.