Increase of etch resistance of deep ultraviolet photoresist by implantation

Ion implantation causes damage to photoresist and brings about the formatio n of a carbonized layer on the surface of the resist. The relationship betw een the extent of damage and the etch resistance of the resist was investig ated. Four ion species, namely, Si, P, As, and BF2 were used. Heavier ions and higher implant energies generally increase the extent of damage and the density of the carbonized layer. Compared to a fresh resist, the formation of a dense carbonized layer increases the etch resistance whereas the form ation of a porous carbonized layer decreases the etch resistance. (C) 1999 American Vacuum Society. [S0734-2101(99)05004-6].