A method for wet etching of Si3N4 in semiconductor device

摘要

PURPOSE: Provided is a wet etching method for silicon nitride film of semiconductor device, which can reduce washing time and the amount of pure water required for washing, as well as improve a yield of the device. CONSTITUTION: The method comprises the steps of (i) inspiring solution mixture solution of ethyl ether and SF6 with CH3F, CF4 gases to saturate the solution with CH3F, CF4 gases, (ii) irradiating the saturated solution with UV to form a radical, and (iii) etching a silicon nitride film on wafer by using a radical reaction solvent comprising radicals of CH3F, CF4 and SF6 gases, in the solution. The reaction temperature at the step(iii) is -20-20 deg.C. The method further comprises the step of (iv) washing the silicon nitride film with pure water, after the step(iii).