Multi-Nozzle Tin Droplet Control for Stable EUV Plasma Generation
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Solution Overview
Problem
The challenge in extreme ultraviolet (EUV) lithography is to synchronize the pulses of high-powered lasers with the movement of tin droplets in laser-produced plasma (LPP) sources to enhance the efficiency and stability of EUV radiation production, which is crucial for advancing semiconductor manufacturing as component sizes decrease.
Innovation Solution
The solution involves a nozzle assembly that generates elongated droplets from multiple small drops, synchronized to arrive at the focal point of the excitation laser pulse, allowing for optimal heating and plasma formation, thereby improving the efficiency and stability of the EUV radiation source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple small drops are aggregated to form elongated droplets, then the energy conversion efficiency and stability of EUV radiation production is improved, but the device complexity increases due to the need for precise synchronization of multiple nozzles and droplet generation
Solution Approach 1:
The system divides the droplet generation into multiple nozzles that each produce small drops, which then aggregate to form elongated droplets. This segmentation allows for better control and synchronization of droplet formation, improving energy conversion efficiency while managing complexity through modular nozzle design
Solution Approach 2:
Multiple small drops from different nozzles are merged to form a single elongated droplet that is then illuminated by the laser pulse. This merging process optimizes the use of laser energy by concentrating it on a larger, more stable droplet structure, improving EUV radiation production efficiency
2Reliability
If the droplet generation is synchronized with laser pulses, then the stability and efficiency of EUV radiation production is enhanced, but the manufacturing precision requirements increase for achieving optimal droplet-laser alignment
Solution Approach 1:
The system generates and positions droplets in advance before the laser pulse arrives, ensuring they are ready at the optimal position for illumination. This preliminary droplet generation and positioning allows for better synchronization and reduces the precision requirements during the actual laser-droplet interaction
Solution Approach 2:
The droplet generation is performed in periodic cycles synchronized with the laser pulse frequency. This periodic action ensures consistent timing and positioning of droplets relative to laser pulses, improving stability while allowing for predictable, repeatable alignment that reduces manufacturing precision challenges
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 energy conversion efficiency and stability of the EUV radiation source, reducing the need for pre-pulse lasers and lowering manufacturing costs, while maintaining high EUV energy production.
Implementation Method 1
a high-power laser pulse is focused on small tin droplets to form highly ionized plasma that emits EUV radiation
Implementation Method 2
the excitation laser heats droplets in the LPP chamber to ionize the droplets to plasma which emits the EUV radiation
Data Source
AI summary
A lithography method in semiconductor fabrication is provided. The method includes generating a plurality of drops of a target material through a plurality of nozzles, adjacent two of the plurality of nozzles having a distance less than a width of a first one of the adjacent two of the plurality of nozzles, wherein the plurality of drops are aggregated to an elongated droplet; generating a laser pulse to convert the elongated droplet into plasma that generates an extreme ultraviolet (EUV) radiation; exposing a semiconductor substrate to the EUV radiation.