Lithographic Apparatus Post-Exposure Bake Integration
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Solution Overview
Problem
The combination of a lithographic apparatus and a processing system often operates at suboptimal efficiency due to variations in timing between exposure and post-exposure bake steps, leading to inconsistencies in critical dimension (CD) and reliability issues, particularly because the slowest component in the cluster determines the throughput, and the handling complexity in the track module affects the overall performance.
Innovation Solution
Integrating a post-exposure bake device within the lithographic apparatus to subject substrates to a predefined temperature cycle, allowing for independent and asynchronous execution of pattern transfer and temperature processing, thereby maintaining consistent critical dimension and improving reliability by minimizing timing variations and optimizing the use of resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a track module combines coat, post exposure bake, and develop processes, then handling complexity increases, but throughput is determined by the slowest step
Solution Approach 1:
The patent segments the processing system by separating the lithographic apparatus from the track module. The lithographic apparatus performs only exposure, while the track module performs coat, post-exposure bake, and develop processes independently. This segmentation allows each module to operate at its own optimal speed without being constrained by the slowest step in a combined system.
Solution Approach 2:
The patent introduces a buffer substrate between the lithographic apparatus and track module, adding a spatial dimension to the process flow. This buffer allows asynchronous operation where the lithographic apparatus can complete exposure on one substrate while the track module processes previous substrates, effectively decoupling the throughput of different modules.
2Manufacturing precision
If post-exposure bake is performed in a separate track module, then timing variation between exposure and bake increases, but device utilization decreases
Solution Approach 1:
The patent implements preliminary action by having the track module prepare substrates (coat, pre-bake) in advance and stage them in a buffer before exposure. This allows the lithographic apparatus to receive ready-to-expose substrates continuously, maintaining tight timing control for post-exposure bake while keeping both modules highly utilized.
Solution Approach 2:
The buffer substrate acts as an intermediary between the lithographic apparatus and track module. It decouples the timing between exposure and post-exposure bake, allowing the lithographic apparatus to maintain consistent exposure-to-bake timing while the track module operates independently, thereby improving both critical dimension stability and device utilization.
3Adaptability or versatility
If lithographic apparatus operates event-driven, then exposure timing varies, but integration with fixed-frequency track module reduces efficiency
Solution Approach 1:
The patent makes the system dynamic by introducing a buffer that can accommodate variable exposure timing. The buffer allows the lithographic apparatus to operate event-driven with varying exposure times while the track module maintains its fixed-frequency operation, as substrates can be staged and transferred at appropriate intervals without constraining either module's operational flexibility.
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
This integration enhances the efficiency and reliability of the substrate processing facility by ensuring consistent critical dimension stability and maximizing the usage of the most expensive components, reducing the impact of failures in lower-value processing modules, and allowing for flexible tuning of production line performance.
Implementation Method 1
the post-exposure bake device configured to subject the substrate to a predefined temperature cycle
Data Source
AI summary
A lithographic apparatus configured to transfer a pattern from a patterning device onto a substrate includes an integrated post-exposure bake device, the post-exposure bake device configured to subject the substrate to a predefined temperature cycle. A post-exposure bake step of the substrate (a temperature cycle) is executed within a predetermined time period after the transfer of the pattern. The lithographic apparatus may be combined with a processing system having one or more processing modules. More efficient use may be made of the combination, allowing flexibility for a device manufacturing method.