EUV Light Generating System Feedforward Control
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Solution Overview
Problem
Existing extreme ultraviolet light generating systems face challenges in maintaining consistent EUV energy output due to shifts in the focusing position of pulsed laser beams caused by thermal deformation of optical elements during burst operations, leading to decreased EUV energy over time.
Innovation Solution
The system employs a combination of actuators and a feedforward control mechanism to adjust and maintain the focusing position of the pulsed laser beam, using control patterns stored in memory to compensate for shifts during burst operations, ensuring stable EUV light generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If burst operations are performed to increase EUV light output, then productivity is improved, but thermal deformation of optical elements causes focusing position shifts that degrade manufacturing precision
Solution Approach 1:
The system performs preliminary actions by storing control patterns in advance that correspond to different burst operation conditions. Before executing a burst operation, the appropriate control pattern is selected and prepared, enabling proactive compensation for thermal deformation effects without real-time measurement delays.
Solution Approach 2:
The system implements feedback control by measuring the actual focusing position during burst operations and comparing it with the target position. Based on this feedback, the actuator adjusts the optical elements to correct focusing position shifts caused by thermal deformation, maintaining manufacturing precision during high-productivity burst operations.
2Stability of the object's composition
If continuous laser beam irradiation is used to maintain plasma generation, then EUV energy consistency is improved, but thermal accumulation causes optical element deformation that reduces reliability
Solution Approach 1:
The system dynamically adjusts the laser beam irradiation parameters and optical element positions during continuous operation. By continuously monitoring focusing position and actively controlling actuators to compensate for thermal deformation, the system maintains EUV energy consistency while adapting to changing thermal conditions, ensuring long-term operational reliability.
3Manufacturing precision
If feedforward control with stored patterns is implemented to compensate focusing shifts, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The system reduces control complexity by performing preliminary action - storing pre-calculated control patterns in memory before operation. These patterns contain the compensation adjustments needed for various burst operation scenarios, eliminating the need for complex real-time calculations and simplifying the control architecture while maintaining high focusing position accuracy.
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 EUV light output by effectively managing shifts in the focusing position, maintaining consistent EUV energy levels throughout burst periods and reducing the impact of thermal deformation on optical elements.
Implementation Method 1
extreme ultraviolet light which is generated by a target turning into plasma by being irradiated with a pulsed laser beam
Data Source
AI summary
An extreme ultraviolet light generating system repetitively outputs extreme ultraviolet light emitted by a target that turns into plasma by being irradiated with a pulsed laser beam. The extreme ultraviolet light generating system may include: a target supply unit that sequentially supplies the target to a plasma generating region set within a chamber, an actuator connected to a laser beam focusing system that focuses the pulsed laser beam output from a laser apparatus that adjusts the focusing position of the pulsed laser beam, an extreme ultraviolet light generation controller that controls the extreme ultraviolet light generating system to output extreme ultraviolet light based on a burst pattern, and an actuator controller that controls the actuator to compensate for shifts of the focusing position of the pulsed laser beam during a burst operation by feedforward control.