Ultrafast Dynamics and Rearrangement of the EUV Photoacid Generator Phenyl Triflate

Area of Science:

• Photochemistry
• Chemical Dynamics
• Materials Science

Background:

• Extreme UV photolithography is essential for semiconductor fabrication.
• Photoacid generators (PAGs) are critical for enhancing lithography processes.
• Understanding PAG behavior under high-energy conditions is vital for process optimization.

Purpose of the Study:

• To investigate the ultrafast dissociative dynamics of phenyl triflate, a common PAG.
• To elucidate the molecular rearrangement and fragmentation pathways of phenyl triflate cations.
• To correlate experimental observations with theoretical calculations.

Main Methods:

• Time-resolved spectroscopy to probe dissociative ionization.
• Measurement of dynamics over the first 5 picoseconds.
• Electronic structure calculations for radical cations.

Main Results:

• Observed dissociative ionization of phenyl triflate cation, including SO2 release and formation of phenyl trifluoromethyl ether cation.
• Detected vibrational coherence linked to a torsional mode of the cation.
• Experimental findings align well with theoretical electronic structure calculations.

Conclusions:

• Phenyl triflate undergoes specific molecular rearrangements and dissociations under ionizing conditions.
• Vibrational coherence provides insights into cation dynamics.
• The study offers valuable data for understanding PAG behavior in industrial applications.