| abstract |
A method for preparing a liquid chemical for forming a water-repellant protective film, the liquid chemical having a solvent and an agent for forming a water-repellant protective film, the liquid chemical being for forming a water-repellent protective film at least on surfaces of recessed portions of an uneven pattern of a wafer having the uneven pattern at its surface, the method including: a first refinement step for eliminating the elements (metal impurities) Na, Mg, K, Ca, Mn, Fe, Cu, Li, Al, Cr, Ni, Zn and Ag in a solvent by distilling the solvent or by a particle-eliminating membrane and an ion exchange resin membrane; a mixing step for mixing the solvent after the first refinement step and an agent for forming a water-repellant protective film; and a second refinement step for eliminating particles in a liquid chemical after the mixing step by a particle-eliminating membrane. |