EUV Light Generation System Pulse Width Optimization
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Solution Overview
Problem
Current extreme ultraviolet (EUV) light generation systems face challenges in achieving high power and efficiency, particularly in the EUV light generation system, where the conversion efficiency (CE) needs to be improved to meet the demands of miniaturized semiconductor processing.
Innovation Solution
The EUV light generation system employs a laser system that emits first prepulse, second prepulse, and main pulse laser light in a specific sequence, with the second prepulse laser light having a longer pulse time width than the main pulse laser light, and a processor controls the irradiation timing to optimize the conversion efficiency by extending the pulse time width of the second prepulse laser light using an optical pulse stretcher, thereby improving the generation of EUV light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the pulse time width of the second prepulse laser light is extended using an optical pulse stretcher, then the conversion efficiency of EUV light generation is improved, but the device complexity increases
Solution Approach 1:
An optical pulse stretcher is introduced as an intermediary device in the laser light path to extend the pulse time width of the second prepulse laser light. This mediator component enables the conversion efficiency improvement by creating a temporal separation between the second prepulse and main pulse, while isolating the complexity of pulse width control from the core EUV generation process
Solution Approach 2:
The pulse time width parameter of the second prepulse laser light is changed from a shorter duration to an extended duration using the optical pulse stretcher. This parameter modification allows the plasma to be pre-heated and prepared in a controlled manner, improving the conversion efficiency of EUV light generation when the main pulse arrives
2Productivity
If multiple prepulse lasers are used in sequence, then the EUV light generation efficiency is improved, but the device complexity increases
Solution Approach 1:
The laser irradiation process is segmented into three distinct stages: first prepulse, second prepulse, and main pulse. Each stage serves a specific function in preparing and exciting the target material to optimize EUV light generation. This segmentation allows for precise control of plasma formation dynamics, improving overall generation efficiency
Solution Approach 2:
The first and second prepulse lasers perform preliminary actions on the target material before the main pulse arrives. The first prepulse initiates plasma formation, while the second prepulse with extended pulse width further prepares the plasma state. These preliminary actions create optimal conditions for the main pulse to generate high-efficiency EUV light
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 enhances the conversion efficiency of the EUV light generation system, allowing for higher power and more efficient EUV light production, which is crucial for advanced semiconductor manufacturing processes.
Implementation Method 1
a laser produced plasma (LPP) type apparatus using plasma generated by irradiating a target substance with pulse laser light
Data Source
AI summary
An extreme ultraviolet light generation system may include a laser system emitting first prepulse laser light, second prepulse laser light, and main pulse laser light in this order; a chamber including at least one window for introducing, into the chamber, the first prepulse laser light, the second prepulse laser light, and the main pulse laser light; a target supply unit supplying a target to a predetermined region in the chamber; and a processor controlling the laser system to irradiate the target with the first prepulse laser light, irradiate the target, having been irradiated with the first prepulse laser light, with the second prepulse laser light having a pulse time width longer than a pulse time width of the main pulse laser light, and irradiate the target, having been irradiated with the second prepulse laser light, with the main pulse laser light temporally separated from the second prepulse laser light.