Patent ID: 8784950

Claim:
A method for forming a conformal film of aluminum oxide on a patterned underlying layer of a substrate by plasma-enhanced atomic layer deposition (PEALD), said patterned underlying layer being a photoresist or a layer of amorphous carbon, said method comprises: (i) adsorbing a precursor on a surface of the substrate in a reaction space whose pressure is controlled at 50 to 1,333 Pa, said precursor being an aluminum compound containing an Al—C bond and an Al—O—C or Al—N—C bond, said substrate being disposed between electrically conductive flat-plate electrodes, wherein the precursor is at least one aluminum compound selected from the group consisting of Al(C x H y (OC z H a ) 2 and Al(C x H y ) 2 (NC z H a ), wherein x, y, z, and a are integers, said precursor being provided with a carrier gas flowing at a rate of 500 to 4,000 sccm; (ii) providing a reactant gas at a flow rate of 10 to 1,000 sccm and a reaction-assisting gas at a flow rate of 500 to 2,000 sccm over the surface of the substrate, said reactant gas being an oxidizing gas, said reaction-assisting gas being an inert gas; (iii) applying RF power from the electrodes to the reactant gas and the reaction-assisting gas to react the adsorbed precursor with the reactant gas on the surface; and (iv) repeating steps (i) to (iii) to form a conformal film of aluminum oxide on the patterned underlying layer of the substrate, wherein the substrate is kept at a temperature of about 200° C. or lower.