There are several disadvantages concerning surface image transfer technique for contact hole fabrication in KrF excimer laser lithography utilizing absorbing photoresist SAL601 (Shipley, chemically amplified negative type). A long development time (MF622, Shipley, 10 min) is the first disadvantage, but this can be improved by using concentrated developer (MF312-CD38, Shipley) without loss of focus margin. Pattern transfer thicknesses limited to an oxide layer of less than 0.2 mum is the second disadvantage, but this can be improved to a thickness of 0.8 mum by using more anisotropic etching conditions. Small depth of focus (DOF) is the third and the most critical disadvantage, and this can be improved by employing low numerical aperture (NA) and high or (coherency factor) exposure conditions (NA=0.35, sigma=0.9). Comparison between the DOF characteristics for a 0.4 mum contact hole using SAL601 and a two-dimensional photointensity simulation has resulted in a simple metric to predict the DOF by mask edge intensity loss from perfect focus to defocus. Although the correlation between the loss and the DOF is weak, the loss is approximately 0.025-0.045. The observed DOF results for 0.35 and 0:32 mum contact holes were in the range of the prediction obtained by the metric except NA=0.45 and sigma=0.3 with 0.35 mum contact hole case.