Selective-area atomic layer deposition using poly(methyl methacrylate) films as mask

Selective-area atomic layer deposition (ALD) was achieved using poly(methyl methacrylate) (PMMA) films as growth inhibiting mask layers. The PMMA films were prepared from PMMA-toluene solution by spin-coating and patterned by UV lithography through a mechanical mask. The patterned PMMA films were tested in several ALD processes, both noble metals and oxides. The tested noble metal processes were iridium, platinum, and ruthenium, and the oxide processes were Al2O3 and TiO2. Al2O3 was deposited using AlCl3 and H,O and trimethylaluminum (TMA) and H2O. TiO2 was deposited using Ti(OMe)(4) and H2O. The growth temperatures were 250-350 degrees C.