Method of dicing a semiconductor wafer using a protective film formed by coating a mixture of water-soluble resin and organic solvent

A method for manufacturing an element chip, comprising:

• a preparation step of preparing a substrate, the substrate having a first surface and a second surface opposite to the first surface, and including a plurality of element regions and dividing regions defining the element regions, the substrate being held on a holding sheet on the second surface side;
• a protective film formation step of spray coating, to the first surface of the substrate, a mixture containing a water-soluble resin and an organic solvent having a higher vapor pressure than water to form a coating film of the mixture, and drying the coating film at a temperature of 50° C. or less, to form a protective film containing the water-soluble resin;
• a laser grooving step of irradiating, with laser light, portions of the protective film that cover the dividing regions, to remove the portions covering the dividing regions, and expose the first surface of the substrate in the dividing regions;
• a dicing step of dicing the substrate into a plurality of element chips by plasma etching the substrate from the first surface to the second surface in the dividing regions in a state in which the element regions are covered by the protective film;
• and
• a removal step of removing the portions of the protective film that cover the element regions,
• wherein the mixture has a solid component ratio of 200 g/L or more, and
• droplets of the sprayed mixture have an average particle size of 12 μm or less.