METHOD FOR ETCHING SILICON SUBSTRATE

PROBLEM TO BE SOLVED: To provide a method for etching a silicon substrate, capable of continuously using an etchant for a long time without replacing it, and forming a texture having low optical reflectance on a surface of the silicon substrate in a stable and inexpensive manner.SOLUTION: A method for etching a silicon substrate for forming unevenness on a surface of the silicon substrate, includes: a pretreatment of supplying a pretreatment liquid containing an additive agent disturbing an etching reaction on the surface of the silicon substrate, and water to the surface of the silicon substrate to allow the additive agent to be deposited on the surface of the silicon substrate; and then an etching treatment of supplying an etchant containing the additive agent, water and an alkaline reagent to the surface of the silicon substrate, to form the unevenness on the surface of the silicon substrate by using wet etching.