A KrF Excimer Laser Lithography for Half Micron Devices

Abstract

An excimer laser stepper has been developed for use in 0.5 µm pattern fabrication. The excimer laser stepper is characterized using a 5× monochromatic quartz lens (exposure area: 10×10 mm2) and a new KrF excimer laser whose oscillation spectrum is limited to a narrow band (FWHM=0.008 nm) by using an etalon. A speckle-free pattern exposure with half-micron order was possible using this apparatus. A resolution of 0.4 µm line and space pattern was obtained by single-layer resist process using a commercial deep UV resist, although its pattern profile was poor. A high-aspect ratio of 0.5 µm line and space pattern was obtained by a trilayer resist process. With this apparatus, a high throughput equivalent to that of a conventional g-line stepper can be expected.