EUV Light Generation Feedback Control for Stable Energy Output
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Solution Overview
Problem
Existing EUV light generation systems face challenges in stabilizing the energy output of extreme ultraviolet light, leading to unstable EUV light generation due to variations in energy levels exceeding allowable thresholds, despite efforts to minimize deviation.
Innovation Solution
The EUV light generation system incorporates a processor that adjusts the optical modulator based on multiple index values, including deviation and variation of EUV light energy, to determine a control gain in PID control, ensuring both deviation and variation are within allowable ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If PID control is applied to adjust the optical modulator, then the EUV light energy stability is improved, but the control system complexity increases due to the need for multiple index values and control gain determination
Solution Approach 1:
The system implements feedback control by continuously monitoring EUV light energy output and adjusting the optical modulator accordingly. The processor receives output from the EUV energy sensor and uses this feedback to modify the optical modulator settings, creating a closed-loop control system that maintains energy stability within allowable ranges.
Solution Approach 2:
The control system performs self-adjustment by automatically determining control gains based on acquired index values without requiring external manual calibration. The processor autonomously processes the index values, calculates appropriate control gains, and adjusts the optical modulator parameters to maintain optimal EUV light energy stability.
2Measurement precision
If multiple index values are acquired for control gain determination, then the control precision is improved, but the measurement and detection difficulty increases
Solution Approach 1:
The control process is segmented into distinct measurement phases, where different index values are acquired at different stages or under different conditions. This segmentation allows the system to collect comprehensive data for control gain determination while organizing the complex measurement process into manageable, systematic steps that reduce overall detection difficulty.
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 stabilizes the EUV light generation by optimizing control gain, maintaining energy output within specified limits, thereby enhancing system stability and efficiency.
Implementation Method 1
a laser produced plasma (LPP) type apparatus using plasma generated by irradiating a target substance with laser light
Data Source
AI summary
Provided is a control method of an extreme ultraviolet light generation system. The extreme ultraviolet light generation system includes a target supply unit configured to supply a target, a laser device configured to irradiate the target with laser light, an EUV energy sensor configured to detect an energy of extreme ultraviolet light generated by the target being irradiated with the laser light, an optical adjuster configured to adjust an energy of the laser light, and a processor configured to adjust the optical adjuster by PID control based on output of the EUV energy sensor. The processor acquires a first index value for the output of the EUV energy sensor and a second index value different from the first index value and determines a control gain in the PID control based on the first and second index values.