EUV Light Generation System Frequency Control
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Solution Overview
Problem
Current extreme ultraviolet (EUV) light generation systems face challenges in maintaining consistent EUV emission efficiency and energy parameters, leading to unsuitable EUV light for advanced semiconductor processing, particularly at 32 nm or less, due to deterioration of EUV collector mirrors and fluctuations in irradiation frequency and pulse energy.
Innovation Solution
The system controls the irradiation frequency of pulse laser light to suppress changes in the energy per unit time of EUV light reflected by the EUV light concentrating mirror, using a processor to adjust the frequency based on measured energy parameters, thereby stabilizing EUV light characteristics and extending the life of the EUV collector mirror.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the irradiation frequency of pulse laser light is increased to maintain EUV light energy output, then the EUV light energy per unit time is maintained, but the deterioration of EUV collector mirror accelerates
Solution Approach 1:
The control device monitors the actual EUV light energy parameter in real-time and adjusts the irradiation frequency of pulse laser light based on this feedback. When the EUV light energy decreases due to mirror deterioration, the system automatically increases the irradiation frequency to compensate and maintain stable output energy, thereby resolving the contradiction between maintaining power output and extending mirror lifespan.
Solution Approach 2:
The system dynamically adjusts the irradiation frequency of pulse laser light based on the actual condition of the EUV collector mirror and the measured EUV light energy. This dynamic control allows the system to optimize the balance between maintaining sufficient EUV light output and reducing the cumulative damage to the mirror, thereby extending its operational life while maintaining required power levels.
2Reliability
If the irradiation frequency of pulse laser light is decreased to extend EUV collector mirror lifespan, then the mirror deterioration is reduced, but the EUV light energy per unit time becomes unstable
Solution Approach 1:
The control device uses real-time feedback from EUV light energy measurements to adjust the irradiation frequency. When the frequency is reduced to extend mirror life, the feedback mechanism detects the resulting energy drop and automatically increases the frequency to compensate, ensuring stable EUV light output while still allowing for reduced cumulative damage compared to constant high-frequency operation.
3Power
If the pulse energy of laser light is increased to compensate for EUV emission efficiency decrease, then the EUV light energy is maintained, but the cumulative damage to EUV collector mirror increases
Solution Approach 1:
The system dynamically adjusts the irradiation frequency of pulse laser light in response to decreasing EUV emission efficiency. Instead of increasing pulse energy which would cause cumulative damage, the system increases the frequency of lower-energy pulses to maintain total EUV light output, thereby distributing the thermal and mechanical stress on the mirror and extending its lifespan while maintaining required power levels.
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 stable EUV light characteristics, ensuring consistent energy parameters and extending the EUV collector mirror's lifespan, thus supporting advanced semiconductor processing requirements by controlling irradiation frequency to stabilize EUV light generation.
Implementation Method 1
a laser produced plasma (LPP) type apparatus using plasma generated by irradiating a target substance with pulse laser light
Implementation Method 2
an EUV light concentrating mirror configured to reflect and concentrate extreme ultraviolet light generated by irradiating a target with the pulse laser light
Data Source
AI summary
An extreme ultraviolet light generation system may include a laser device configured to emit pulse laser light, an EUV light concentrating mirror configured to reflect and concentrate extreme ultraviolet light generated by irradiating a target with the pulse laser light, and a processor configured to receive a first energy parameter of the extreme ultraviolet light and control an irradiation frequency of the pulse laser light with which the target is irradiated so that change in a second energy parameter related to energy per unit time of the extreme ultraviolet light reflected by the EUV light concentrating mirror is suppressed.