BEAM ANALYSIS: Onboard excimer laser metrology advances photolithography

摘要

A real-time beam metrology module aboard a 193 nm excimer light source can monitor laser beam parameters such as beam divergence, near-field profiles, polarization, energy density, and beam pointing during wafer exposure, improving immersion lithography process control. Current excimer light sources for semiconductor photolithography are monitored for basic energy, wavelength, and bandwidth parameters needed to image a pattern and expose photoresist on a wafer. However, beam parameters such as pointing and divergence have been characterized and measured with off-line service tools historically. But a real-time beam metrology module aboard Cymer's 193 nm excimer light source can dramatically improve argon fluoride (ArF) immersion lithography quality by optimizing exposure-beam parameters, improving wafer imaging results and long-term wafer performance trends.