The present invention is directed to provide an
etching agent for a
semiconductor substrate, which is capable of
etching a
titanium (Ti)-based
metal film or a
tungsten (W)-based
metal film on a
semiconductor substrate and an
etching method using relevant etching agent, and relates to a liquid for preparing the etching agent for a
semiconductor substrate composed of a solution comprising (A)
hydrogen peroxide, (B) a phosphonic acid chelating agent having a hydroxyl group, (C) a basic compound, and (D-1) a
copper anticorrosive and / or (D-2) 0.01 to 3% by weight of two or more kinds of anion species other than phosphonic acid chelating agents having a hydroxyl group, in which anion species have no oxidizing power, an etching method characterized by etching a
titanium (Ti)-based
metal film or a
tungsten (W)-based metal film on a semiconductor substrate using relevant etching agent for a semiconductor substrate, further, a solution comprising (B) a phosphonic acid chelating agent having a hydroxyl group, (C) a basic compound, and (D-1) a
copper anticorrosive and / or (D-2) anion species other than phosphonic acid chelating agents having a hydroxyl group, in which anion species have no oxidizing power.