Hiroshi Suganuma

Deep-UV lithography using continuous-wave 266-nm radiation from an all solid state frequency quadrupled Nd:YAG laser

A new lithography technique using continuous wave (CW) 266 nm radiation from an all solid state frequency quadrupled Nd:YAG laser is described and demonstrated. This laser has proved to be a highly efficient and promising deep UV light source in fabrication of 0.25 micron design rule device. Furthermore, we obtained 0.2 micron L/S pattern with phase shift mask. Speckle free images are obtained with rotating diffuser. The performance and potential of this new laser as a light source of microlithography are discussed and compared with KrF excimer laser theoretically and experimentally.

Efficient all-solid state 213-nm laser source for microlithography

We describe a 0.4W average power at maximum, frequency-quintupled Q-switched Nd:YAG laser at a repetition rate of 7 kHz, which is a potential light source for next generation microlithography. Calculated results for the conversion efficiencies considering pump depletion will be discussed. Our results allow to foresee further scaling up 213 nm power up to the 1W level by increasing the fundamental power.

Progress in all-solid-state deep-ultraviolet coherent light sources

High power deep ultraviolet (UV) radiation has attracted much attention in areas such as photo-lithography, micro fabrication, material processing and ultra high density optical disk mastering. We report progress in improving the quality of Czochralski-grown (beta) -BaB2O4 (BBO) which is essential for generating high average output power in the deep ultraviolet regime. We obtained 1.5 W of cw 266 nm output using an external resonant doubler, 1.3 W of 213 nm output from a flashlamp pumped Q-switched Nd:YAG laser and more than 0.4 W of 213 nm radiation from a commercial 6 W diode-pumped high repetition rate Q-switched Nd:YAG laser using our melt-grown BBO crystals for the nonlinear frequency conversion. Using the cw 266 nm output speckle-free 0.25 micrometers photolithography and micro-fabrication was demonstrated.