Abstract: [Problem] To provide a method for preparing a protective film-forming liquid chemical, in a method for producing a wafer having at its surface an uneven pattern and containing silicon element at least at a part of the uneven pattern. The liquid chemical forms a water-repellent protective film on the uneven pattern of the wafer and improves a cleaning step which tends to induce a pattern collapse, and particularly provides a good persistence (pot life) of the improving effect. [Solution] A method for preparing a liquid chemical for forming a water-repellent protective film, the liquid chemical being for forming a water-repellent protective film at the time of cleaning the wafer at least on surfaces of recessed portions of the uneven pattern, the liquid chemical containing a nonaqueous organic solvent, a silylation agent, and an acid or base.

Abstract: The present invention provides a pressure feed container capable of ensuring the cleanliness of a liquid such as a protective film-forming liquid chemical or a protective film-forming liquid chemical kit for preparing the liquid chemical even after long-term storage, and also capable of suppressing electrostatic charge in the liquid. The present invention provides a pressure feed container configured to store a protective film-forming liquid chemical or a protective film-forming liquid chemical kit that is mixed into the protective film-forming liquid chemical, and to transfer a liquid upon application of pressure to the inside of the container, the protective film-forming liquid chemical being for forming a water-repellent protective film on at least surfaces of recessed portions of an uneven pattern formed on a surface of a wafer containing a silicon element at least at a part of the uneven pattern.

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.

Abstract: Disclosed herein is a method for preparing a liquid chemical for forming a water-repellent protective film, the liquid chemical being for forming the water-repellent protective film at the time of cleaning a wafer having at its surface an uneven pattern and containing silicon element at least at a part of the uneven pattern at least on surfaces of recessed portions of the uneven pattern, the liquid chemical containing a nonaqueous organic solvent, a silylation agent, and an acid or a base. The method includes (i) adjusting a water content of the nonaqueous organic solvent to 200 mass ppm or less by dehydration; and (ii) mixing the nonaqueous organic solvent, the silylation agent, and the acid or the base after the adjusting step.