CO2 Laser Amplifier Cleaning for Long-Term EUV Power Stability
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Solution Overview
Problem
Existing EUV lithography systems face significant energy decay in laser power over time, leading to increased maintenance costs and reduced efficiency, as the CO2 lasers used in these systems suffer from long-term power loss and contamination issues that affect the generation of EUV light.
Innovation Solution
Implementing a hydrogen-doped gas cleaning process to remove contamination layers, such as silicon dioxide, from the catalyst surfaces within the laser power amplifiers, which extends the lifespan of the CO2 lasers and maintains EUV generation efficiency by periodically cleaning the surfaces during both online and offline operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If CO2 lasers are used to generate EUV light in lithography systems, then EUV light generation is achieved, but long-term energy decay of 10% per year or more occurs
Solution Approach 1:
The patent applies preliminary action by introducing a hydrogen-doped gas cleaning process that proactively removes contamination layers (such as silicon dioxide) from catalyst surfaces before they can cause significant laser power degradation. This preventive maintenance approach extends laser lifespan by addressing contamination issues before they lead to the 10% per year energy decay problem
Solution Approach 2:
The patent implements self-service through an automated cleaning system that periodically purges the laser amplifier chamber with hydrogen-doped gas to remove build-ups on catalyst surfaces. This self-maintaining mechanism reduces the need for manual intervention and extends operational life without requiring external service personnel
2Productivity
If laser power amplifiers operate continuously for extended periods, then production efficiency is maintained, but contamination builds up on catalyst surfaces causing power loss
Solution Approach 1:
The patent applies periodic action by implementing scheduled cleaning cycles where the laser amplifier chamber is purged with hydrogen-doped gas at predetermined intervals during operation. This periodic maintenance removes contamination accumulations before they significantly impact laser power stability, allowing continuous operation while maintaining reliability
Solution Approach 2:
The patent ensures continuity of useful action by designing the cleaning process to occur during non-critical periods or with minimal disruption to laser operation. The hydrogen-doped gas purge removes contamination without requiring extended downtime, maintaining production efficiency while preventing power loss
3Reliability
If replacement or repair of lasers is performed to address power decay, then laser performance is restored, but time-consuming and expensive maintenance is required
Solution Approach 1:
The patent implements self-service through an automated cleaning system that periodically purges the laser amplifier chamber with hydrogen-doped gas to remove contamination. This self-maintaining mechanism restores laser performance without requiring manual disassembly, part replacement, or expensive service interventions
Solution Approach 2:
The patent applies discarding and recovering by removing accumulated contamination (such as silicon dioxide layers) from catalyst surfaces through hydrogen-doped gas purification. This process recovers laser performance by eliminating the degraded material without requiring disposal or replacement of entire laser components
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 effectively stabilizes the EUV light output, reducing the energy decay rate and maintaining production efficiency by continuously removing build-ups, thus extending the useful life of the EUV lithography systems and preventing significant power losses.
Implementation Method 1
The mixing gas reacts with and removes the build-up by generating gaseous by-products
Implementation Method 2
a high-power laser beam, as generated by a carbon dioxide (CO2) laser
Implementation Method 3
By focusing a high-power laser beam... onto small fuel droplet targets in order to transition it into a highly-ionized LPP
Implementation Method 4
EUV lithography employs a laser-produced plasma (LPP), which emits EUV light
Implementation Method 5
This plasma emits EUV light with a peak maximum emission of about 13.5 nm or smaller
Data Source
AI summary
An apparatus for manufacturing semiconductors includes a power amplifier to power a laser, a catalyst disposed in the power amplifier, an inlet port, and an exhaust port. The inlet port introduces a mixing gas to an interior of the power amplifier during a cleaning operation so that the mixing gas contacts a surface of the catalyst having a build-up thereon. The mixing gas reacts with and removes the build-up by generating gaseous by-products. The exhaust port removes the gaseous by-products from the power amplifier.