TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: (I) comprises: (a), where the nitrogen of -CHYa-CHYbYc forms part of a pyridinium or imidazolium ring system; at least one tetraalkylammonium fluoride salt; at least one (a) comprising ethyltrimethylammonium fluoride, diethyldimethylammonium fluoride, triethylmethyl ammonium fluoride, tetraethylammonium fluoride, butylethylmethyl isopropyl ammonium fluoride, tetraisopropyl ammonium fluoride, tetra-n-butylammonium fluoride, tetra-sec-butylammonium fluoride, tetrapentyl ammonium fluoride, octyltrimethylammonium fluoride, phenyl triethyl ammonium fluoride, triphenyl ethyl ammonium fluoride, phenyl ethyldimethyl ammonium fluoride, 1,1-dimethyl-pyrrolidinium fluoride, 6-azonia-spiro(5.5)undecane fluoride, 1-ethyl-1-methyl-azetidinium fluoride, 1,2-dimethyl-3-azonia-spiro(2.2)pentane fluoride, 1-ethyl-pyridinium fluoride, 1-isopropyl-3-methyl-3H-imidazol-1-ium fluoride, 1-methyl-1-azonia-bicyclo(2.2.2)octane fluoride, 1,4-dimethyl-1,4-diazoniabicyclo(2.2.2)octane difluoride, 1,1,4,4-tetramethylpiperazinediium difluoride, or N1,N2-diethyl-N1-(2-(ethyldimethylammonio)ethyl)-N1,N2,N2-trimethylethane-1,2-diaminium trifluoride; at least one (a) in a concentration of 20-80 wt%; at least an alcohol besides of water as solvent and optionally surface tension controlling agents; a solvent comprising water, methanol, ethanol, n-propanol, iso-propanol, n-butanol, tert-butanol, iso-butanol, sec-butanol, ethylene glycol, propylene glycol, mono- and polyhydric alcohols having higher carbon number, acetone, methyl ethyl ketone and/or methyl n-amyl ketone; and an etchant. Preferred Components: (a) comprises at least one alkyl group being an ethyl or butyl group or a larger hydrocarbon group having up to 8C. Preferred Method: (I) is a printable hot melt material composed of pure salts, and which are fluidized by heating. The etchant is activated at 50-300 degrees C, preferably 70-300 degrees C, and which is printable at a temperature of room temperature to 150 degrees C. The method comprises: contactless application of (I) by printing or coating, where (I) is heated to a temperature of room temperature to 100 degrees C, preferably room temperature to up to 70 degrees C; and heating the applied (I) to 70-300 degrees C to generate or activate the active etchant and etching the exposed surface areas of functional layers. (I) is heated to a temperature of room temperature to 70 degrees C and applied by spin or dip coating, drop casting, curtain or slot dye coating, screen or flexo printing, gravure or ink jet aerosol jet printing, offset printing, micro contact printing, electrohydrodynamic dispensing, roller or spray coating, ultrasonic spray coating, pipe jetting, laser transfer printing, or pad or off-set printing. The heated (I) is applied to etch functional layers or layer stacks consisting of silicon oxide, silicon nitride, silicon oxy nitrides, aluminum oxide, titanium oxide or amorphous silicon. EXAMPLE - Typical composition comprised of tetraethylammonium fluoride (62.5%) in deionized water.