MOPA Laser System for High-Repetition EUV Generation
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Solution Overview
Problem
Current EUV light source apparatuses, particularly those using LPP systems, face challenges in achieving high repetition and high power CO2 pulse lasers, as existing TEA CO2 lasers are unable to realize the required high repetition and high power levels necessary for advanced microfabrication processes.
Innovation Solution
A laser apparatus comprising a MOPA or MOPO system with a semiconductor master oscillator and a molecular gas amplifier, capable of amplifying single- or multiple-longitudinal mode laser light, and a controller for wave shape and pulse output timing control, is used to generate plasma and emit extreme ultraviolet light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If TEA CO2 laser is used for EUV light source, then plasma generation capability is achieved, but high repetition and high power requirements cannot be met
Solution Approach 1:
The laser system is divided into multiple independent modules: master oscillator, preamplifier, and main amplifier stages. Each module operates independently to optimize its specific function, allowing the system to achieve both high power and high repetition rates that cannot be obtained with a single TEA CO2 laser module.
2Power
If high power laser is used to generate plasma, then EUV light output is increased, but control over pulse shape and timing becomes difficult
Solution Approach 1:
The system incorporates feedback control mechanisms where the master oscillator generates precisely timed and shaped pulses that serve as reference signals. The amplification stages maintain temporal and spatial coherence with the master oscillator, enabling precise control over pulse shape and timing even at high power levels through active feedback stabilization.
Solution Approach 2:
The laser system employs dynamic control of pulse parameters through the master oscillator, which can independently adjust pulse width, repetition rate, and temporal profile. This dynamic control capability is maintained through the amplification chain, allowing real-time optimization of pulse characteristics for different plasma generation requirements.
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 configuration enables the generation of high-repetition, high-power EUV light with precise control over pulse shape and timing, enhancing the efficiency and accuracy of microfabrication processes beyond 32 nm scales.
Implementation Method 1
a master oscillator constructed from a semiconductor laser being able to oscillate a single-longitudinal or multiple-longitudinal mode laser light
Implementation Method 2
an amplifier including at least one of a MOPA and a MOPO each of which amplifies a single-longitudinal or multiple-longitudinal mode laser light, an amplifiable agent of the amplifier being a molecular gas
Implementation Method 3
a target material supplied inside a vacuum chamber is excited by irradiation with a laser light and thus be turned into plasma
Implementation Method 4
a target material supplied inside a vacuum chamber is excited by irradiation with a laser light and thus be turned into plasma
Implementation Method 5
luminance can be made extremely high as close to the black-body radiation because plasma density can be made higher
Implementation Method 6
a light with various wavelength components including an EUV light is emitted from the generated plasma
Data Source
AI summary
A laser apparatus comprises an amplifier including at least one of a MOPA and a MOPO each of which amplifies a single-longitudinal or multiple-longitudinal mode laser light, an amplifiable agent of the amplifier being a molecular gas, a master oscillator constructed from a semiconductor laser being able to oscillate a single-longitudinal or multiple-longitudinal mode laser light of which wavelength is within one or more amplification lines of the amplifier; and a controller executing a wave shape control adjusting a pulse shape and/or a pulse output timing of a single-longitudinal or multiple-longitudinal mode laser light outputted from the master oscillator.