Wet cleaning stripping of etch residue after trench and via opening formation in dual damascene process
View Patent ↗After trench line pattern openings and via pattern openings are formed in a inter-metal dielectric insulation layer of a semiconductor wafer using trench-first dual damascene process, the wafer is wet cleaned in a single step wet clean process using a novel wet clean solvent composition. The wet clean solvent effectively cleans the dry etch residue from the plasma etching of the dual damascene openings, etches back the TiN hard mask layer along the dual damascene openings and forms a recessed surface at the conductor metal from layer below exposed at the bottom of the via openings of the dual damascene openings.
1. A wet cleaning solvent for cleaning the trench and via openings in a dual damascene structure after the trench and via openings are dry etched, said cleaning solvent consisting essentially of:
at least four of but no more than eight of the propylene glycol monomethyl ether, ethylene glycol, 1,4-butynediol, butyrolactone, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, tetrahydrothiophene-1,1-dioxide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, cyclopentanone, dimethylsulfoxide, ethylenediaminetetraacetic acid, Ethylenebis(oxyethylenenitrilo)tetraacetic acid, EGTA, trans-1,2-Diaminocyclohexane-N,N,N′,N′-tetraacetic acid hydrate, diethylenetriamine-pentaacetic acid, DTPA, 1,4,7,10-tetraazacyclododecane-tetraacetic acid, triethylenetetramine-N,N,N′,N″,N′″,N′″-hexaacetic acid, nitrilotriacetic acid, propionic acid, 1,2,3-Benzotriazole, benzene-1,2,4-tricarboxylic acid, 1,2,4-triazole, 7-methylindole-2-carboxylic acid, thioglycerol, 4-Methylmorpholine N-oxide monohydrate, isonicotinic acid N-oxide, 4-Methoxypyridine-N-oxide hydrate, 3-Hydroxypyridine-N-oxide, pyridine-N-oxide, tetramethyl ammonium hydroxide, tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide, ammonium fluoride, tetrabutylammonium fluoride, and 1,3-dimethyl-2-imidazolidinone,
wherein the wet cleaning solvent comprises less than 500 ppb of each of the following trace elements: Al, Ca, Cr, Cu, Fe, Pb, Li, Mg, Mn, Ni, K, and Na.
2. The wet cleaning solvent of claim 1 , wherein the wet cleaning solvent comprises:
0.01-30 wt. % peroxide;
a pH value of 7-10;
de-ionized water content of less than 15 wt %; and
a viscosity of 5-25 c.p.
3. The wet cleaning solvent of claim 1 , wherein the wet cleaning solvent has the following metal etch rate: TiN 0.5-50 Å/min, Cu 0.5-50 Å/min, Co 0.5-50 Å/min, Copper silicide (Cu 5 Si) 0.5-50 Å/min.