US Patent 7192860 Highly selective silicon oxide etching compositions

Silicon oxide etching solutions containing the product of at least one bifluoride source compound dissolved in a solvent consisting of at least one carboxylic acid, and further comprising from about 0.5 to about 3 percent by solution weight of hydrofluoric acid and from about 1 to about 5 percent by solution weight of water, wherein the total concentration of bifluoride source compound is between about 1.25 and about 5.0 moles per kilogram of solvent. Methods for selectively removing silicon oxides and metal silicates from metal surfaces are also disclosed.