EUV Light Generation System Laser Irradiation Position Optimization
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Solution Overview
Problem
Current extreme ultraviolet (EUV) light generation systems for semiconductor manufacturing face challenges in maximizing EUV light output due to suboptimal laser irradiation positions, leading to inefficient energy distribution and reduced output energy.
Innovation Solution
The system adjusts the laser irradiation position by shifting the optical path axis of the pulse laser light away from a reference position towards the EUV light concentrating mirror, utilizing EUV sensors to maximize the average radiation energy and employing correction coefficients to optimize the radiation energy distribution, thereby increasing the output energy of the EUV light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the laser irradiation position is set at the reference position (center of target), then the energy distribution is symmetric, but the output energy of EUV light is not maximized
Solution Approach 1:
The patent applies parameter changes by deliberately shifting the laser irradiation position from the reference position (center of target) to an optimized position determined through measurement and calculation. This positional parameter modification enables maximization of EUV light output energy while maintaining acceptable symmetry of energy distribution, directly resolving the contradiction between power output and position accuracy.
2Power
If the laser irradiation position is shifted away from the reference position, then the output energy of EUV light is maximized, but the symmetry of energy distribution deteriorates
Solution Approach 1:
The patent applies local quality by creating an asymmetric energy distribution that is optimized for specific directional output toward the EUV light concentrating mirror. Rather than maintaining uniform symmetry, the system deliberately creates a non-uniform energy distribution pattern that maximizes EUV generation in the desired direction, accepting local asymmetry to achieve global optimization of power output.
3Measurement precision
If multiple EUV sensors are used to measure radiation energy in different directions, then the measurement precision of energy distribution is improved, but the device complexity increases
Solution Approach 1:
The patent applies feedback by using multiple EUV sensors to measure radiation energy in different directions and feeding this information back to determine the optimal laser irradiation position. The measurement results from multiple sensors are processed through calculation and optimization algorithms to identify the position that maximizes average radiation energy, creating a closed-loop system that continuously optimizes performance based on actual measurements.
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 adjustment significantly enhances the output energy of the EUV light, improving the efficiency of the EUV light generation system and ensuring higher energy delivery to the intermediate focal point, which is crucial for semiconductor manufacturing processes.
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 EUV light concentrating mirror configured to reflect EUV light radiated from the first region and concentrate the EUV light to a second region
Data Source
AI summary
An extreme ultraviolet light generation system includes a chamber including a first region; a target supply unit supplying a target to the first region; a laser device outputting pulse laser light; an optical system including an optical element to guide the pulse laser light to the first region; an irradiation position adjustment mechanism adjusting a laser irradiation position with respect to the target; an EUV light concentrating mirror arranged such that the pulse laser light passes outside the EUV light concentrating mirror and is guided to the first region; a plurality of EUV sensors measuring radiation energies of the EUV light radiated from the first region in mutually different radiation directions; and a processor controlling the irradiation position adjustment mechanism as setting a target irradiation position of the pulse laser light to a laser irradiation position away from a reference position in a direction toward the EUV light concentrating mirror.