EUV Collector Contamination Balancing via Selective Deposition
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Solution Overview
Problem
Extreme ultraviolet lithography (EUV) collector contamination leads to poor pupil uniformity and asymmetry, which cannot be adequately corrected by existing uniformity correction modules, resulting in performance degradation and eventual tool unavailability due to asymmetric contamination.
Innovation Solution
A temperature control module with multiple temperature control elements on the collector is used to identify and balance contamination regions by forming a second contamination region symmetric to the first, thereby compensating for asymmetric contamination and maintaining pupil uniformity through selective deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a uniformity correction module (UNICOM) is used to correct pupil non-uniformities, then illumination uniformity is improved, but asymmetric contamination cannot be adequately corrected and performance degrades over time
Solution Approach 1:
The system performs preliminary contamination balancing by using temperature control elements to create a second contamination region symmetric to the first contamination region before the asymmetric contamination can cause performance degradation. This proactive approach prevents the need for frequent collector replacements and maintains tool performance over extended periods.
Solution Approach 2:
The invention intentionally introduces controlled asymmetry through selective deposition on specific regions of the collector. By creating a second contamination region that is symmetric to the first contamination region, the system transforms the harmful asymmetric contamination into a balanced symmetric pattern that does not degrade pupil uniformity.
2Illumination intensity
If the collector is changed to restore tool performance, then pupil uniformity is restored, but tool unavailability increases and productivity decreases
Solution Approach 1:
The system performs preliminary contamination balancing by using temperature control elements to create a second contamination region symmetric to the first contamination region before the asymmetric contamination can cause performance degradation. This proactive approach prevents the need for frequent collector replacements and maintains tool performance over extended periods.
3Illumination intensity
If temperature control elements are used to create symmetric contamination regions, then collector contamination is balanced and pupil uniformity is maintained, but device complexity increases
Solution Approach 1:
The temperature control module serves multiple functions: it controls the overall temperature of the collector, selectively heats specific regions to control contamination deposition, and maintains tool performance over extended periods. This multi-functionality justifies the added complexity by eliminating the need for separate contamination balancing systems.
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 approach extends the operating life of the EUV source by periodically compensating for contamination build-up, maintaining tool performance and increasing throughput by preventing dead pixels and asymmetry in the beam profile.
Implementation Method 1
balancing collector contamination of a light source by selective deposition
Implementation Method 2
enabling a subset of a plurality of temperature control elements positioned on the collector to cause a second contamination region to be formed on the collector symmetric to the first contamination region
Data Source
AI summary
A method includes identifying a first contamination region of a collector of a light source and enabling a subset of a plurality of temperature control elements positioned on the collector to cause a second contamination region to be formed on the collector symmetric to the first contamination region.