Surface tension of substrates and layers used in semiconductor technology (e.g., Si, SiO2, Si3N4, AlCu, and WTi) as well as surface tension of materials of photolithography as resists and developers were determined by contact angle measurements. Resists and developers could be divided into two groups with polar and nonpolar behavior, respectively. The pretreatment of the substrates (cleaning, dehydration, and exposure to humidity) influences the surface tension. It was found that surface modification by primers, for example, hexamethyldisilazane and trimethylsilydiethylamine provides stable and reproducible surface tension. To reduce defect density of resist structures, a general optimization approach of surface tension was derived and successfully applied, using Si and AlCu as substrates in a typical photolithographic process. The results show a good adhesion of resist will be achieved if the work of adhesion is greater than 5 dyn/cm. A suggestion is given of process window of the contact angle is given for certain combinations of types of resist and developer.