Quarter- and sub-quarter-micron deep UV lithography with chemically amplified positive resist

The resist performance for quarter- and sub-quarter-micron domains using partially t-butoxycarbonylmethylated poly(4-vinylphenol) (BOCM-PVP) as a polymer dissolution inhibitor is reported. This resist contains some additives to improve resolution and process stability. This resist has high resolution, with linearity down to 0.225 mu m L & S at 38 mJ/cm(2) on a KrF excimer laser stepper (NA=0.5, sigma=0.5) with a COG mask. Using a halftone phase shifting mask, 0.175 mu m L & S patterns are resolved with a 1 mu m depth of focus (DOF) on a KrF excimer stepper (NA=O.5, sigma=0.7, 1/2 annular illumination). The line width change vs. PEB temperature (Delta CD/Delta T) is 1.3 nm/degree. The line width shift over time between exposure and PEB is within +/-0.01 mu m even after 1 hr delay in a basic-contamination-free environment (NH3<1 ppb).