A semiconductor substrate is first provided. The semiconductor substrate includes a material layer and a patterned photoresist layer disposed on the material layer. Subsequently, a contact etching process is performed on the material layer by utilizing the patterned photoresist layer as an etching mask so to form an etched hole in the material layer. Thereafter, a solvent cleaning process is carried out on the semiconductor substrate by utilizing a cleaning solvent. Next, a water cleaning process is performed on the semiconductor substrate by utilizing deionized water. The temperature of the deionized water is in a range from 30° C. to 99° C.