EUV Light Source Control for Higher Laser-to-EUV Conversion
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Solution Overview
Problem
Existing EUV light generation systems face challenges in efficiently generating and controlling EUV energy output for semiconductor manufacturing, particularly in achieving high EUV energy ratios relative to laser energy, which is crucial for microfabrication at 10 nm or less.
Innovation Solution
The system incorporates a prepulse laser device, a main pulse laser device, actuators for independent laser position adjustment, an EUV sensor, a laser energy sensor, a target sensor, and a controller to optimize the ratio of EUV energy to laser energy by adjusting the irradiation positions based on diffusion target characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the irradiation position of the main pulse laser light is adjusted to maximize EUV energy output, then the EUV energy to laser energy ratio increases, but the system complexity increases due to the need for independent position control
Solution Approach 1:
The system divides the laser position control into two independent segments: the first actuator controls the prepulse laser position while the second actuator controls the main pulse laser position. This segmentation allows independent optimization of each laser's irradiation position on the diffusion target, enabling maximization of EUV energy output without requiring complex coupled control mechanisms.
Solution Approach 2:
The system implements dynamic, independent adjustment of laser irradiation positions through two separate actuators. The second actuator specifically enables real-time optimization of the main pulse laser position relative to the diffusion target based on feedback from EUV energy measurements, allowing the system to adapt and maximize EUV output dynamically while maintaining manageable complexity through modular control architecture.
2Manufacturing precision
If independent actuators are used to adjust laser positions, then the control precision over EUV energy generation improves, but the device complexity increases
Solution Approach 1:
The system applies local quality control by dedicating specific actuators to specific functions: the first actuator optimizes the prepulse laser position while the second actuator optimizes the main pulse laser position. This localized control approach enables precise adjustment of each laser's irradiation point on the diffusion target, improving overall control precision while keeping each control module relatively simple and independent.
Solution Approach 2:
The system implements feedback control where EUV energy measurements are used to adjust the laser positions. The controller receives EUV energy data and uses it to optimize the irradiation positions of both lasers through their respective actuators. This feedback mechanism improves control precision by continuously adapting to actual EUV generation conditions while maintaining device simplicity through established feedback control methodologies.
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 enhances the efficiency and control of EUV energy generation, improving the precision and effectiveness of semiconductor manufacturing processes.
Implementation Method 1
a prepulse laser device configured to output prepulse laser light to be radiated to a target supplied into a chamber
Implementation Method 2
a main pulse laser device configured to output main pulse laser light to be radiated to a diffusion target generated by the radiation of the prepulse laser light
Implementation Method 3
a laser produced plasma (LPP) type apparatus using plasma generated by irradiating a target substance with laser light
Implementation Method 4
an EUV sensor configured to detect EUV energy of EUV light generated by the diffusion target being irradiated with the main pulse laser light
Data Source
AI summary
An EUV light generation system includes a prepulse laser device outputting prepulse laser light to be radiated to a target supplied into a chamber; a main pulse laser device outputting main pulse laser light to be radiated to a diffusion target generated by the radiation of the prepulse laser light; a first actuator adjusting an irradiation position of the prepulse laser light; a second actuator adjusting an irradiation position of the main pulse laser light; an EUV sensor detecting EUV energy; a laser energy sensor detecting laser energy of the main pulse laser light; a target sensor imaging the diffusion target; and a controller controlling, after controlling the first actuator based on a characteristic value of the diffusion target calculated from an image of the diffusion target, the second actuator so that a ratio of the EUV energy to the laser energy detected by the laser energy sensor becomes large.