Using a Laser Beam to Fabricate Patterns in Polysilicon Films
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
An excimer laser (ArF - 193 nm) beam 10 is directed onto portions of a polysilicon film 14 through a standard mask 12. The laser beam irradiation is carried out in a slightly oxidizing environment. In the exposed area 18 (Fig. 1) a porous silicon-rich oxide film will be formed as a result. The porous region is then etched away by a wet or dry etch process, since the etch rate for the porous region is 30 - 40 times that of the regions not exposed by the laser beam. The resulting opening 18A (Fig. 2) in the polysilicon is realized without the use of photoresist processing.