Intense plasma discharge source at 13.5 nm for extreme-ultraviolet lithography

Area of Science:

• Atomic Physics
• Plasma Physics
• Optics

Background:

• Extreme-ultraviolet (EUV) light sources are crucial for advanced lithography.
• Laser-produced plasma (LPP) sources are currently dominant but have limitations in efficiency.
• Developing efficient and narrow-band EUV sources is an ongoing research challenge.

Purpose of the Study:

• To investigate the potential of a fast capillary discharge to generate EUV emission.
• To characterize the output energy, spectral properties, and efficiency of the Li(2+) Lyman-? transition.
• To compare the performance of this source with existing LPP sources for lithography applications.

Main Methods:

• Utilized a lithium hydride capillary for a fast capillary discharge.
• Excited the Li(2+) Lyman-? transition to produce 13.5 nm emission.
• Measured emission energy, spot size, and spectral bandwidth.
• Calculated wallplug efficiency.

Main Results:

• Achieved an emission of 6 mJ/pulse at 13.5 nm.
• 75% of the energy was concentrated within a 0.6 mm spot size.
• The emission exhibited a narrow bandwidth, suitable for Mo:Si multilayer mirrors.
• Demonstrated a wallplug efficiency of 0.1%, nearly an order of magnitude higher than LPP.

Conclusions:

• Fast capillary discharge is a promising method for generating efficient EUV light.
• The characterized emission is comparable to LPP sources for extreme-ultraviolet lithography.
• This technique offers a more efficient alternative for future lithography imaging systems.