Patent ID: 6174452
Filing Date: 2001-01-16
Classification: C03C,C04B,C09K,H01L,Y02E

Abstract:
The M-A-P method of etching a masked metal oxide film on a substrate in which a metal (M) and an etch liquid comprising acid (A) and a reduced metal oxide metal penetration control agent (P) are brought into contact with the sample at room temperature such that the metal oxide is reduced to its metallic form through the action of active (H.sup.o) produced in the reaction of M with A, and in which etching stops when the reduced metal oxide metal becomes impenetrable to H.sup.o, wherein the metal oxide is tin oxide, the metal (M) is zinc and the etch liquid comprises hydrochloric acid (HCl) in a concentration of 0.4-1.0 M H.sup.+ and ferrous chloride (FeCl.sub.2) and/or ferrous sulfate (FeSO.sub.4) in a concentration of 0.3-0.5 M Fe.sup.++.