EUV Chamber Mirror Cleaning With Variable Hydrogen Etching Flow
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Solution Overview
Problem
Existing EUV light generation systems face challenges in effectively removing tin deposits from the reflection surface of the EUV light concentrating mirror while minimizing the risk of hydrogen blistering, which can degrade the reflectance and power of the EUV light output.
Innovation Solution
The EUV light generation chamber device incorporates a first etching gas supply unit with a variable flow velocity control and a second etching gas supply unit, along with an optical path switching mechanism, to manage the etching gas flow and minimize exposure time on the mirror surface, thereby balancing etching efficiency with blistering prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If etching gas flow velocity is increased to remove tin deposits from the reflection surface, then cleaning efficiency is improved, but hydrogen blistering risk increases
Solution Approach 1:
The etching gas supply system uses variable flow velocity control, switching between high flow velocity (for efficient tin deposit removal) and low flow velocity (for preventing hydrogen blistering) based on real-time reflectance monitoring. This dynamic adjustment resolves the contradiction by adapting the flow velocity to the current cleaning stage and mirror surface condition.
Solution Approach 2:
The system incorporates a reflectance monitoring mechanism that continuously measures the reflection surface quality and provides feedback to the control unit. Based on this feedback, the control unit adjusts the etching gas flow velocity appropriately, thereby resolving the contradiction between cleaning efficiency and blistering prevention through closed-loop control.
2Object-affected harmful factors
If etching gas flow velocity is decreased to prevent hydrogen blistering, then blistering risk is reduced, but tin deposit removal efficiency decreases
Solution Approach 1:
The etching process uses periodic action by alternating between high flow velocity phases (for effective tin deposit removal) and low flow velocity phases (for blistering prevention). The control unit switches between these phases based on monitoring data, resolving the contradiction by applying different flow velocities at appropriate times during the cleaning cycle.
Solution Approach 2:
The system dynamically adjusts etching gas flow velocity based on real-time reflectance monitoring and cleaning progress. This dynamic control enables the system to optimize the balance between tin deposit removal efficiency and hydrogen blistering prevention, rather than using a fixed flow velocity.
3Manufacturing precision
If prolonged etching gas exposure is applied to remove tin deposits, then cleaning thoroughness is improved, but hydrogen blistering occurs
Solution Approach 1:
The reflectance monitoring system provides real-time feedback on the cleaning progress and mirror surface condition. The control unit uses this feedback to determine when to adjust or stop the etching gas flow, ensuring thorough cleaning while preventing hydrogen blistering through timely intervention.
Solution Approach 2:
The system performs preliminary assessment of the mirror surface condition through reflectance monitoring before applying prolonged etching gas exposure. This preliminary action enables the control unit to adjust the etching gas flow velocity and exposure duration appropriately, achieving thorough cleaning while preventing blistering.
4Productivity
If high flow velocity etching gas is continuously supplied, then tin deposit removal speed is improved, but reflectance degradation occurs due to blistering
Solution Approach 1:
The etching gas supply system dynamically adjusts flow velocity based on real-time reflectance monitoring and cleaning progress. This dynamic control enables high-speed tin deposit removal while maintaining reflectance stability by reducing flow velocity when blistering risk is detected.
Solution Approach 2:
The system incorporates a closed-loop feedback mechanism where reflectance monitoring data is continuously fed back to the control unit, which adjusts the etching gas flow velocity accordingly. This feedback control resolves the contradiction by optimizing the balance between removal speed and reflectance stability.
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 maintains the reflectance and power of the EUV light output by efficiently removing tin deposits while reducing the risk of hydrogen blistering, ensuring stable EUV light generation.
Implementation Method 1
a laser produced plasma (LPP) type apparatus using plasma generated by irradiating a target substance with laser light has been developed
Implementation Method 2
an extreme ultraviolet light concentrating mirror arranged in the internal space and including a reflection surface which reflects the extreme ultraviolet light
Implementation Method 3
a first etching gas supply unit configured to supply an etching gas containing a hydrogen gas to the reflection surface
Data Source
AI summary
An extreme ultraviolet light generation chamber device includes a chamber generating, at an internal space thereof, extreme ultraviolet light by irradiating a droplet target of tin with laser light to turn the droplet target into plasma; a target supply unit supplying the droplet target into the internal space; an extreme ultraviolet light concentrating mirror arranged in the internal space and including a reflection surface which reflects the extreme ultraviolet light; a first etching gas supply unit supplying an etching gas containing a hydrogen gas to the reflection surface having a flow velocity at the reflection surface variable; a data generation unit generating data reflecting reflectance of the extreme ultraviolet concentrating mirror; and a processor controlling the first etching gas supply unit to decrease the flow velocity when the data indicates that an amount of decrease in the reflectance is equal to or more than a reference value.