Maskless patterned etching of silicon dioxide by inkjet printing

A method of directly patterning silicon dioxide layers without the use of a mask is described. The method uses an inkjet device for the patterned deposition of a solution containing fluoride ions onto an acidic water-soluble polymer layer formed over the silicon dioxide. The deposited solution reacts with the polymer layer, at the locations where it is deposited, to form an active etchant that etches the silicon dioxide under the polymer layer to form a pattern of openings in the dielectric layer. The resulting patterned silicon dioxide layer can be used to facilitate local diffusions and metal contacts to the underlying silicon, or to enable etching of the underlying silicon. The method requires small amounts of chemicals and produces significantly less hazardous chemical waste than existing immersion etching methods.