Optical methods produce integrated-circuit features as small as 0.08 microns

Optical methods produce integrated-circuit features as small as 0.08 microns

A research grou¥led by Grant Willson of the University of Texas at Austin (Austin, TX) has obtained integrated-circuit feature sizes as small as 0.08 µm using optical lithographic techniques. Current standard production feature sizes are 0.35 µm, although some advanced-fabrication plants are producing features of 0.25 µm and testing production of 0.18-µm features. Feature sizes smaller than 100 nm were expected to take u¥to a decade to develo¥(see Laser Focus World, July 1997, p. 82) and to require technologies other than optical. At 80 nm, circuit lines are about 320 atoms wide and could potentially lead to chips that are 10 to 100 times faster than today.

To make the tiny features, the grou¥developed a new photoresist--an amorphous polyolefin with polymers specifically designed to interact with 193-nm light. Placed on a 0.2-mm square, the new photoresist was illuminated in an experimental deep-ultraviolet stepper from Integrated Solutions (Tewksbury, MA) that incorporated a next-generation argon fluoride excimer laser emitting at 193 nm from Cymer (San Diego, CA). Features were generated using an etched-quart¥phase-shift photomask produced by Dupont Photomasks (Round Rock, TX). The research is sponsored by the Semiconductor Research Council (Research Triangle Park, NC) and Sematech (Austin, TX).