This paper presents the high-aspect-ratio pattern fabrication method for KrF excimer laser lithography. The alkaline surface treatment of a resist before exposure can enhance the contrast of a conventional naphthoquinone-diazide-based deep UV positive resist. It has been found that the improvement depends upon the structure of the resist. High-aspect-ratio sub-half-micron patterns of the deep UV resist with an easy azo-coupling reaction were successfully attained using this simple method without compromising sensitivity.