EUV Controller Pulse Intensity Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current laser produced plasma (LPP) EUV systems experience oscillations in EUV energy generation due to unstable plasma conditions, which are not effectively addressed by fixed pulse width settings, leading to inefficiencies in EUV output power.
Innovation Solution
Implementing an EUV energy detector and controller system that measures EUV energy generated by a first laser pulse, compares it to an expected amount, and adjusts the intensity of subsequent laser pulses using a gain factor to stabilize the plasma, while maintaining constant pulse width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed pulse width is used for the main laser pulse, then the system structure is simple and easy to operate, but oscillation in EUV energy generation occurs due to unstable plasma conditions
Solution Approach 1:
The system dynamically adjusts the intensity of the main laser pulse based on real-time plasma stability feedback. The controller modifies the main pulse intensity relative to the pre-pulse intensity according to plasma conditions, transitioning from a static fixed pulse width approach to a dynamic intensity modulation approach that adapts to changing plasma states.
Solution Approach 2:
The system implements a feedback control mechanism where the controller monitors plasma stability and adjusts the main pulse intensity accordingly. The controller receives information about plasma conditions and modifies the main pulse intensity to maintain optimal plasma stability, creating a closed-loop control system that continuously adapts to maintain reliable EUV energy generation.
2Power
If the intensity of the main laser pulse is increased to improve EUV output power, then EUV energy generation increases, but plasma instability and oscillation worsen
Solution Approach 1:
The system employs dynamic intensity modulation where the main pulse intensity is continuously adjusted based on real-time plasma stability feedback. This allows the system to optimize EUV output power by increasing intensity when plasma conditions are favorable while reducing intensity when instability is detected, achieving high power output with maintained plasma stability.
Solution Approach 2:
The system changes the intensity parameter of the main laser pulse dynamically based on plasma conditions. By modulating the main pulse intensity relative to the pre-pulse intensity according to real-time plasma stability measurements, the system optimizes EUV energy generation while preventing plasma instability and oscillation.
3Reliability
If pulse width variation or timing modulation is used to reduce oscillation, then plasma stability improves, but device complexity increases
Solution Approach 1:
The system changes the intensity parameter of the laser pulses to control plasma stability. By modulating the main pulse intensity based on plasma feedback, the system achieves effective oscillation reduction through a straightforward intensity control mechanism rather than complex pulse width or timing modulation systems.
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 stabilizes the plasma, leading to more consistent and efficient EUV energy generation by counteracting forces within the plasma chamber, thereby improving the realization of expected EUV energy output.
Implementation Method 1
converting a material into a plasma state that has one or more elements, e.g., xenon, lithium, tin, indium, antimony, tellurium, aluminum, etc., with one or more emission line(s) in the EUV range. In one such method, often termed laser produced plasma ('LPP'), the required plasma can be produced by irradiating a target material, such as a droplet, stream or cluster of material having the desired line-emitting element, with a laser beam at an irradiation site.
Implementation Method 2
measuring, by an extreme ultraviolet (EUV) energy detector, an amount of EUV energy generated in a plasma chamber of a laser produced plasma (LPP) EUV system
Data Source
AI summary
In a laser produced plasma (LPP) extreme ultraviolet (EUV) system, a plasma created from droplets irradiated by a laser pulse can become destabilized. The instability of the plasma can reduce the amount of EUV energy generated over time. While other systems seek to stabilize the plasma by varying a pulse width of the laser pulses, the systems and methods described herein stabilize the plasma by varying an intensity of the laser pulses. The intensity of the laser pulses is varied based on a comparison of the amount of EUV energy generated from current pulse to an expected amount of EUV energy. The intensity of the laser pulses can be varied on a pulse-by-pulse basis by an EUV controller that instructs a pulse actuator.