OPTICALLY ENHANCED-LINE LITHOGRAPHY FOR 0.3-MU-M RANDOM LOGIC APPLICATIONS

A conventional lithographic illumination system with binary masks does not provide the processing latitude needed to meet the critical dimen sion (CD) specifications for 0.30-mu m random-logic poly gates. The us e of a high numerical-aperture stepper and a resist process with botto m antireflection coating combined with annular illumination and an att enuated phase-shifting mask resulted in enlarged individual process wi ndows. The overlapping combined lithography window, however, was narro wer than the conventional illumination system. The incorporation of op tical proximity correction (OPC) improved these windows and across-chi p linewidth uniformity. This optically enhanced i-line process with OP C effectively printed 0.30-mu m circuits with CD variations of less th an +/-10%.