EUV Lithography Shroud and Gas Flow Debris Management
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Solution Overview
Problem
The collector in laser-produced plasma (LPP) EUV radiation sources in extreme ultraviolet lithography systems is prone to contamination due to debris deposition, leading to reduced reflectivity and increased complexity in manufacturing, which affects the overall efficiency and longevity of the system.
Innovation Solution
Integration of a gas flow mechanism with the collector, including a gas supply module and exhaust system, to chemically react with debris and remove it, combined with a shroud and shutter cover design to stabilize metallic droplet trajectories and shield against shock waves, thereby reducing contamination and maintaining the collector's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a collector is used in LPP EUV radiation sources to collect and reflect EUV light, then EUV conversion efficiency is improved, but the collector becomes prone to contamination from debris deposition, reducing its reflectivity and usable lifetime
Solution Approach 1:
The patent extracts and removes debris particles from the system before they can contaminate the collector. A debris removal system is implemented that actively captures and eliminates particles in the vicinity of the collector, preventing deposition on the collector surface and maintaining its reflectivity over time.
Solution Approach 2:
The patent introduces an intermediary debris removal system between the plasma generation region and the collector. This intermediary system acts as a protective mediator that intercepts debris particles and prevents them from reaching the collector, thereby preserving collector performance without affecting the EUV light collection function.
2Productivity
If the collector is exposed to debris from metallic droplet vaporization, then EUV light generation is maintained, but contamination accumulates on the collector surface, increasing manufacturing complexity and reducing system longevity
Solution Approach 1:
The patent applies preliminary action by implementing a debris removal system that proactively eliminates particles before they can contaminate the collector. This preventive approach avoids the need for complex manufacturing processes to create contamination-resistant collectors and reduces maintenance requirements, thereby simplifying the overall system while maintaining productivity.
3Power
If metallic droplets are directed at high velocity to ensure precise targeting for EUV generation, then EUV conversion efficiency is improved, but shock waves and debris generation increase, affecting system stability
Solution Approach 1:
The patent converts the harmful shock waves and debris generated by high-velocity droplet impact into manageable conditions. By implementing a debris removal system and optimizing the droplet delivery mechanism, the system harnesses the high-velocity impact for efficient EUV generation while simultaneously managing the associated harmful effects, transforming a problematic situation into a controlled and beneficial process.
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
The solution effectively reduces debris deposition on the collector, enhancing its usable lifetime and maintaining the EUV conversion efficiency and lithography throughput by preventing contamination and maintaining precise droplet targeting for EUV light generation.
Implementation Method 1
a gas flow mechanism with the collector, including a gas supply module and exhaust system, to chemically react with debris and remove it
Implementation Method 2
a shroud and shutter cover design to stabilize metallic droplet trajectories and shield against shock waves
Implementation Method 3
a laser beam is emitted to encounter the metallic droplet to generate an EUV light
Implementation Method 4
a laser beam is emitted to encounter the metallic droplet to generate an EUV light
Data Source
AI summary
An extreme ultraviolet (EUV) lithography method includes causing a first metallic droplet to move along a shroud and through an aperture of the shroud at a first velocity, and adjusting an open area of the aperture of the shroud. After adjusting the open area of the aperture of the shroud, a second metallic droplet is caused to move along the shroud and through the aperture of the shroud at a second velocity, in which the second velocity is different from the first velocity.