Patent ID: 7727415

Claim:
A fine treatment agent, which is used for the fine processing of a multilayer film including a tungsten containing film and a silicon compound containing film, comprising hydrogen fluoride, nitric acid, at least one of ammonium fluoride or ammonium chloride, and 0.001 weight percent to 0.1 weight percent of a non-ionic surfactant, wherein an etching rate for said tungsten containing film at 25° C. which is within a range from 0.5 nm/min to 5000 nm/min and an etching rate for said silicon compound containing film at 25° C. which is within a range from 0.5 times to 2 times the etching rate for said tungsten containing film at 25° C., wherein X, Y and Z satisfy the following relational expressions when the content of said hydrogen fluoride is X mol/kg the content of the nitric acid is Y mol/kg and the content of the at least one of ammonium fluoride or ammonium chloride is Z mol/kg, [Formula 1] Z≦ 1.25 Y− 1.75 (1) Z> 1.4 Y− 3 (2) Z≦− 0.973 Y+ 0.108×(100−4 X ) (3) 0.5≦X≦10, Y>0, 0<Z≦6 (4).