The interaction of silicon wafers with alkaline solutions of octylphenol polyethylene oxide nonionic surfactants of different ethylene oxide chain length has been characterized at 25, 50, and 75 degrees C. Wettability of silicon wafers was improved significantly at higher temperatures. Surfactants with long ethylene oxide chains exhibited less adsorption than surfactants with short ethylene oxide chains, and increase in solution temperature resulted in increased adsorption. Generally, the addition of surfactants to alkaline solution decreased the surface roughness of silicon; however, the degree of reduction of surface roughness was influenced by the length of ethylene oxide chain and conditioning temperature.