Selective-Area Atomic Layer Deposition Using Poly(methyl methacrylate) Films as Mask Layers

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 Al 2 O 3 and TiO 2 . Al 2 O 3 was deposited using AlCl 3 and H 2 O and trimethylaluminum (TMA) and H 2 O. TiO 2 was deposited using Ti(OMe) 4 and H 2 O. The growth temperatures were 250−350 °C.