Laser Apparatus Trigger Signal Synchronization for EUV Generation
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Solution Overview
Problem
Current extreme ultraviolet (EUV) light generating apparatuses face challenges in maintaining synchronized operation of pulsed laser beams with changing repetition frequencies, leading to desynchronization of optical switches and amplifiers, which affects the quality and timing of EUV light output.
Innovation Solution
A laser apparatus with a control unit that adjusts the output timing and pulse width of trigger signals to semiconductor lasers, ensuring that pulsed laser beams pass through optical switches at predetermined frequencies, even when operating conditions change, by using a master repetition frequency and frequency division settings to synchronize the operation of multiple QCLs and optical switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the repetition frequency of EUV light is changed, then the productivity of the EUV light generating apparatus is improved, but the synchronization between laser beams and optical switches deteriorates
Solution Approach 1:
The control unit dynamically adjusts the pulse width of trigger signals based on the repetition frequency. When the repetition frequency changes, the control unit calculates the appropriate pulse width to ensure that optical switches remain synchronized with laser beams, thereby maintaining reliable operation across different productivity levels.
Solution Approach 2:
The system changes the parameter of trigger signal pulse width in response to repetition frequency changes. By adjusting this parameter, the control unit ensures that the timing and duration of optical switch activation remain synchronized with the laser beam pulses, resolving the contradiction between productivity improvement and synchronization maintenance.
2Device complexity
If the pulse width of trigger signals is fixed, then the device complexity is reduced, but the ability to maintain synchronization under varying operating conditions deteriorates
Solution Approach 1:
The control unit automatically adjusts the pulse width of trigger signals based on the repetition frequency without requiring external intervention or complex manual calibration. This self-adjusting mechanism maintains synchronization while keeping the overall device complexity manageable through automated control logic.
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 solution ensures that pulsed laser beams with desired properties are output at desired timings, maintaining synchronization and amplification efficiency even when the repetition frequency of EUV light changes, thereby stabilizing the EUV light generating system.
Implementation Method 1
a semiconductor laser that outputs a laser beam when a trigger signal is input thereto
Implementation Method 2
an optical switch that switches between a state in which the laser beam passes therethrough and a state in which the laser beam does not pass therethrough
Data Source
AI summary
A laser beam having desired properties is output at desired timings. A laser apparatus is a laser apparatus for use with an extreme ultraviolet light generating apparatus that generates extreme ultraviolet light at a repetition frequency which is set in advance, and may be equipped with: a semiconductor laser that outputs a laser beam when a trigger signal is input thereto; an optical switch that switches between a state in which the laser beam passes therethrough and a state in which the laser beam does not pass therethrough, provided along the optical path of the laser beam; and a control unit configured to output the trigger signal to the semiconductor laser at a frequency which is an integer multiple of the repetition frequency, and to control the optical switch such that the laser beam passes therethrough at the repetition frequency.