EUV Target Supply Device Droplet Interval Control
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Solution Overview
Problem
EUV light generation systems face issues with faulty coalesced droplets and satellites, leading to decreased EUV light energy and potential laser device damage due to irregular droplet intervals and distances, which affect the stability and efficiency of the EUV light generation process.
Innovation Solution
A target supply device with a control unit that measures passage time intervals and inter-droplet distances, adjusts the duty value of the electric signal driving the piezoelectric element, and regulates the operation to maintain proper droplet intervals and distances, preventing faulty coalesced droplets and satellites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the excitation element operates with a fixed duty value, then the operation is simple, but the droplet interval becomes unstable leading to faulty coalesced droplets and satellites
Solution Approach 1:
The control unit measures the actual droplet interval using the droplet detection unit and adjusts the duty value of the excitation element based on this measurement. This closed-loop feedback mechanism ensures stable droplet intervals while preventing faulty coalesced droplets and satellites, resolving the contradiction between reliability and simplicity.
Solution Approach 2:
The system dynamically changes the duty value parameter of the excitation element based on measured droplet intervals. By adjusting this key parameter in real-time, the system maintains optimal droplet formation conditions without requiring complex mechanical modifications, balancing reliability improvement with minimal added complexity.
2Use of energy by moving object
If the duty value is not adjusted, then the control is simple, but EUV light energy decreases due to faulty droplets
Solution Approach 1:
The control unit uses feedback from the droplet detection unit to monitor droplet intervals and automatically adjusts the duty value to prevent faulty droplet formation. This ensures consistent EUV light energy output without requiring manual intervention or complex operational procedures, maintaining ease of operation while improving energy efficiency.
Solution Approach 2:
The system performs self-adjustment by automatically measuring droplet intervals and modifying the excitation element's duty value without external intervention. This self-service capability maintains high EUV light energy while keeping the operation simple, as the system corrects itself without user involvement.
3Reliability
If droplet intervals are not regulated, then the system operates simply, but laser device damage may occur
Solution Approach 1:
The system takes preliminary action by continuously monitoring droplet intervals and adjusting the duty value before faulty droplets can form and potentially damage the laser device. This preventive approach ensures laser device safety without requiring complex emergency response mechanisms, as the problem is addressed before it occurs.
Solution Approach 2:
The droplet detection unit provides continuous feedback on droplet intervals to the control unit, which adjusts the excitation element's duty value to prevent conditions that could lead to laser device damage. This feedback loop ensures device safety with minimal added complexity, as the monitoring and adjustment are integrated into the existing system.
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
The solution ensures stable EUV light generation by suppressing the formation of faulty coalesced droplets and satellites, maintaining high EUV light energy and preventing laser device damage, thereby improving the overall efficiency and reliability of the EUV light generation system.
Implementation Method 1
an excitation element configured to vibrate the target substance to be output from the nozzle to thereby generate a droplet of the target substance
Implementation Method 2
a droplet detection unit configured to detect the droplet output from the nozzle
Data Source
AI summary
A target supply device may include a nozzle configured to output a liquid target substance contained in a tank, an excitation element, a droplet detection unit configured to detect a droplet output from the nozzle, a passage time interval measurement unit configured to measure a passage time interval of droplets, and a control unit. The control unit may be configured to set a proper range of the passage time interval, change the duty value of the electric signal to be input to the excitation element, store the passage time interval measurement values of the droplets generated with respect to a plurality of duty values and variation thereof in association with the duty values, and determine an operation duty value based on the variation from among the duty values with which the passage time interval measurement values are within the proper range, among the duty values.