Laser Device Dynamic Gas Pressure Control for Energy Stability
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Solution Overview
Problem
Current laser devices for exposure apparatuses face challenges in achieving a wide dynamic range of output energy while maintaining energy stability, as changing the voltage or gas composition often leads to increased variations in laser output energy, making it difficult to meet the required output range from 90 W to 60 W with minimal fluctuations.
Innovation Solution
The implementation of a MOPA or MOPO-type laser device with a seed laser and gas discharge-pumped amplifier stages, coupled with a laser gas control device that adjusts total pressure and a laser power source control device that adjusts pump intensity, allowing for continuous changes in laser output energy by controlling voltage and gas pressure to maintain stability and range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If voltage or gas composition is changed to achieve wide dynamic range of output energy, then output energy range is improved, but energy stability deteriorates with increased variations in laser output energy
Solution Approach 1:
The patent implements dynamic control of gas pressure and pump intensity parameters to adapt the laser system to different output energy requirements. The gas pressure is dynamically adjusted based on the requested energy level, and the pump intensity is modulated in response to feedback from energy detection, enabling the system to maintain optimal performance across a wide dynamic range from 60W to 90W without sacrificing energy stability.
Solution Approach 2:
The patent changes physical parameters (gas pressure and pump intensity) to achieve different output energy levels while maintaining stability. By adjusting gas pressure as a primary parameter and pump intensity as a secondary parameter, the system can transition between different operating points (60W, 75W, 90W) with controlled energy variations, resolving the contradiction between wide range and stability.
2Adaptability or versatility
If gas pressure and pump intensity are adjusted to meet varying exposure process demands, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent employs feedback control mechanisms where detection means measure the actual laser output energy and feed this information back to the control means. The control means then adjusts gas pressure and pump intensity based on this feedback to achieve the requested energy level. This closed-loop feedback system provides adaptability to meet varying exposure demands while managing complexity through automated control rather than manual intervention.
Solution Approach 2:
The control means serves multiple functions: it receives requests from the exposure apparatus, detects actual output energy, calculates appropriate gas pressure and pump intensity settings, and controls both parameters simultaneously. This multi-functional control system reduces overall device complexity by consolidating control operations into a single integrated unit rather than separate control systems for each parameter.
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 configuration enables the laser device to output energy within the range of 90 W to 60 W with minimal variations, ensuring stable operation and flexibility in meeting varying exposure process demands without degrading optical elements or increasing energy consumption.
Implementation Method 1
at least one gas discharge-pumped amplifier stage that receives output light from the seed laser as an input, amplifies the light, and outputs the amplified light
Data Source
AI summary
A laser device for an exposure apparatus may include: a MOPA-type or MOPO-type laser device including a seed laser and at least one gas discharge-pumped amplifier stage that receives output light from the seed laser as an input, amplifies the light, and outputs the amplified light; and at least one of a laser gas control device that at least changes the total pressure of a laser gas in said amplifier stage in accordance with requested energy and a laser power source control device that at least changes pump intensity of discharge electrodes in said amplifier stage in accordance with said requested energy, in a case where the energy of laser output light from said laser device is to be changed discontinuously in response to a request from an exposure apparatus.