EUV Target Supply Dual Threshold Satellite Detection
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Solution Overview
Problem
Current extreme ultraviolet (EUV) light generation devices face challenges in detecting satellites, which cause contamination and reduce EUV output due to the lack of a separate detection threshold for satellites, leading to improper laser beam irradiation and decreased performance.
Innovation Solution
A target supply device with a control unit that sets two detection thresholds, allowing for the detection of satellites and calculation of an evaluation parameter to adjust the piezoelectric duty value, ensuring accurate droplet generation and minimizing satellite generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single detection threshold is used for droplet detection, then the system is simple to operate, but satellites cannot be detected causing contamination and reduced EUV output
Solution Approach 1:
The single detection threshold is segmented into two distinct thresholds: a first detection threshold for detecting droplets and a second detection threshold (with smaller absolute value from base line) for detecting satellites. This segmentation allows the system to differentiate between droplets and satellites based on their distinct signal characteristics, enabling satellite detection without complicating the overall system architecture.
Solution Approach 2:
Different detection thresholds are applied to different detection needs: the first detection threshold is optimized for droplet detection to ensure proper laser irradiation, while the second detection threshold is specifically tuned for satellite detection to identify contamination sources. This local quality approach allows each threshold to be optimized for its specific function.
2Reliability
If satellites are not detected, then the system operates continuously without interruption, but EUV optical energy is lost and laser apparatus may be damaged
Solution Approach 1:
The system implements feedback by continuously monitoring droplet and satellite signals through the dual threshold detection mechanism. When satellites are detected via the second detection threshold, the control unit receives feedback information and adjusts the piezoelectric duty value to optimize droplet generation. This feedback loop enables real-time protection of the laser apparatus while maintaining continuous operation.
Solution Approach 2:
The system performs preliminary detection of satellites before they can cause damage to the laser apparatus. By using the second detection threshold to identify satellites in advance, the control unit can adjust parameters proactively, preventing potential damage before it occurs and ensuring continuous productive operation.
3Object-generated harmful factors
If the piezoelectric duty value is adjusted to reduce satellites, then satellite generation is minimized, but droplet generation may be affected
Solution Approach 1:
The piezoelectric duty value is dynamically adjusted based on real-time satellite detection results. The control unit modifies the duty value in response to satellite signals detected by the second threshold, optimizing droplet generation quality while minimizing satellite formation. This dynamic adjustment allows the system to adapt to changing conditions and maintain optimal performance.
Solution Approach 2:
The system changes the piezoelectric duty parameter in response to satellite detection. By adjusting this critical parameter based on feedback from the second detection threshold, the control unit optimizes the balance between droplet generation quality and satellite minimization, preventing harmful effects while maintaining manufacturing precision.
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 enables effective satellite detection without affecting the light emission trigger, allowing for continuous droplet laser beam irradiation, reducing EUV optical energy loss and preventing laser apparatus damage.
Implementation Method 1
a vibration element driven upon receiving of an electric signal that is a square wave, the vibration element being configured to generate a droplet of the target substance by vibrating the target substance to be output from the nozzle
Implementation Method 2
a laser beam with which the droplet is to be irradiated
Implementation Method 3
in which plasma is generated; and a target supply device configured to supply a target as a generation source of the plasma into the chamber
Implementation Method 4
extreme ultraviolet light generation device configured to generate extreme ultraviolet (EUV) light
Data Source
AI summary
A target supply device according to an aspect of the present disclosure includes a vibration element configured to generate a droplet by vibrating a target substance to be output from a nozzle 80, a droplet detection unit configured to detect the droplet, and a control unit 70. A first detection threshold and a second detection threshold to be compared with a detection signal from the droplet detection unit are set to the control unit 70. The first detection threshold is used to generate a light emission trigger for a laser beam. The second detection threshold has a smaller absolute value from a base line of the detection signal than the first detection threshold. The control unit 70 calculates an evaluation parameter for a satellite based on the detection signal and the second detection threshold, and determines a duty value of an electric signal suitable for operation of the vibration element based on the evaluation parameter.