Abstract

The semiconductor community is currently intensively searching for the best light source for 1 Gbit DRAM lithography. A reliable high repetition rate laser source at 213 nm may become an excellent choice for deep UV lithography. Although the ArF excimer laser is the front-runner to be the 1 Gbit lithography light source, materials and coating reliability problems at 193 nm are slowing optical system development. Besides rapid degradation of MgF₂ windows on the ArF laser, recent results indicating that fused silica degradation at ArF wavelengths to be four to eight times greater than degradation at 213 nm [1] cast doubt on the ultimate suitability of the ArF excimer laser as the next source for microlithography. Therefore, demonstration of watt level lithography sources at 213 nm based on fifth harmonic generation of a high-repetition-rate diode-pumped pulsed Neodymium laser has become an pressing issue.

© 1995 Optical Society of America