EUV Droplet Timing Control for Precise Laser Irradiation
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Solution Overview
Problem
Existing EUV light generation apparatuses face challenges in achieving precise control over the generation and delivery of droplet targets for efficient EUV light production, leading to inefficiencies in semiconductor manufacturing processes.
Innovation Solution
The apparatus includes a target supply unit with a vibrating element to generate droplet targets, a target passage detection device, a delay circuit, and a processor that controls the interval between droplet targets and sets delay times for optimal EUV light generation, integrating image data to specify the most emphasized droplet target position for precise EUV light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If regular intervals between droplet targets are used, then the control is simpler, but the EUV light generation efficiency is reduced due to overlapping plasma regions
Solution Approach 1:
The patent applies asymmetry by using irregular intervals between droplet targets instead of regular intervals. This asymmetric timing pattern prevents plasma regions from overlapping while maintaining simple control logic through automated processing, thereby improving EUV light generation efficiency without significantly increasing control complexity
Solution Approach 2:
The patent uses periodic action by generating droplet targets at regular intervals from the droplet generator, then applying irregular intervals through selection and filtering processes. This periodic generation combined with selective irregular spacing optimizes plasma separation while maintaining system simplicity
2Manufacturing precision
If delay time is not accurately controlled, then the system operation is simpler, but the irradiation position deviates from the droplet target
Solution Approach 1:
The patent implements feedback by detecting droplet target passage with a detection device and using this information to dynamically adjust the delay time for laser irradiation. This feedback mechanism ensures accurate irradiation positioning while automating the timing control process, thereby improving precision without requiring complex manual timing adjustments
Solution Approach 2:
The patent applies preliminary action by pre-calculating and setting the delay time based on detected droplet passage timing before the actual irradiation occurs. This preliminary timing adjustment ensures that the laser irradiation is precisely synchronized with droplet target arrival, improving manufacturing precision while simplifying real-time control complexity
3Measurement precision
If multiple image data are integrated, then the droplet target position is more accurately specified, but the processing time increases
Solution Approach 1:
The patent applies partial action by integrating only a selected number of image data frames rather than processing all available images. This selective integration achieves sufficient droplet target position detection accuracy while limiting processing time, thereby improving measurement precision without excessive time loss
Solution Approach 2:
The patent extracts and processes only the essential image data containing droplet target information, separating relevant data from unnecessary frames. This extraction approach improves position detection accuracy by focusing on critical information while reducing overall processing time by excluding redundant data
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 precision and efficiency of EUV light generation, improving the accuracy of semiconductor manufacturing by ensuring consistent and controlled droplet target delivery and emission timing.
Implementation Method 1
a vibrating element configured to apply vibration to the target substance to be output from the tank to generate a droplet target of the target substance
Implementation Method 2
a laser device configured to generate extreme ultraviolet light by irradiating, with light, the droplet target
Implementation Method 3
generate extreme ultraviolet light by irradiating, with light, the droplet target
Data Source
AI summary
An extreme ultraviolet light generation apparatus includes a target supply unit, a target passage detection device, a delay circuit, a laser device, a target image capturing device, and a processor. Here, the processor controls the vibrating element to provide irregular intervals between droplet targets adjacent to each other; generates integrated image data by integrating plural pieces of image data imaged at different times; specifies a position, in the integrated image data, of the droplet target most emphasized in the integrated image data; and sets a delay time based on a distance from a position of the most emphasized droplet target to a second detection position.