EUV Laser Gain Control via Plasma Feedback
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Solution Overview
Problem
The instability of laser beam output in extreme ultraviolet (EUV) light generation affects the reliability of exposure processes in semiconductor manufacturing, leading to inconsistent pattern formation in downsized semiconductor devices.
Innovation Solution
A method involving plasma generation in an amplifying tube using a gas as a gain medium, with real-time detection and feedback control to maintain the virtual laser gain within a target range, ensuring consistent EUV light production for semiconductor device manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser beam output is used to generate EUV light, then EUV exposure can be performed, but the unstable output causes deterioration of exposure process reliability
Solution Approach 1:
The patent implements a feedback control system that detects the actual laser gain using a power meter and spectrometer, compares it with a target range, and adjusts plasma generation parameters accordingly. This closed-loop feedback mechanism stabilizes the laser beam output by continuously correcting deviations, thereby improving exposure process reliability without sacrificing EUV generation capability.
Solution Approach 2:
The patent changes physical parameters of the plasma state (such as gas composition, pressure, and power input) to optimize and stabilize laser gain. By adjusting these parameters within a target range and maintaining them through feedback control, the system achieves stable laser beam output while maintaining effective EUV light generation.
2Stability of the object's composition
If plasma state is controlled to maintain virtual laser gain within target range, then laser beam output consistency is improved, but measurement and control complexity increases
Solution Approach 1:
The patent introduces intermediate measurement devices (power meter and spectrometer) that indirectly detect plasma state by measuring laser beam characteristics. These intermediaries translate complex plasma parameters into measurable quantities, enabling control without direct plasma measurement and reducing overall system complexity while maintaining output consistency.
Solution Approach 2:
The patent replaces direct mechanical or physical plasma control with optical measurement and electronic feedback control. By using light-based detection (power meter and spectrometer) and electronic parameter adjustment, the system achieves precise plasma state control without complex mechanical intervention mechanisms.
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 stability and consistency of the laser beam output, improving the reliability of the EUV exposure process and subsequent semiconductor device manufacturing by eliminating errors due to aging measuring devices and maintaining optimal plasma states.
Implementation Method 1
generating plasma in an amplifying tube by using gas as a gain medium
Implementation Method 2
generating plasma by applying RF power to an electrode in the amplifying tube supplied with the mixed gas
Implementation Method 3
generating EUV light by reacting droplets with a laser beam output from the amplifying tube
Data Source
AI summary
A method of manufacturing a semiconductor includes generating plasma in an amplifying tube using gas as a gain medium; detecting a state of the plasma generated in the amplifying tube; determining a virtual laser gain based on the detected state of the plasma; controlling the state of the plasma such that the virtual laser gain is within a target range; and manufacturing the semiconductor device including performing an exposure process on a substrate using a laser beam output from the amplifying tube adjusted to have the virtual laser gain within the target range.