Method for neutral beam processing based on gas cluster ion beam technology and articles produced thereby

A photoresistless method of forming a patterned hard mask on a surface of a substrate comprising the steps of:

• providing a reduced pressure chamber;
• forming a gas cluster ion beam comprising gas cluster ions comprising carbon atoms within the reduced pressure chamber;
• accelerating the gas cluster ions to form an accelerated gas cluster ion beam along a beam path within the reduced pressure chamber;
• promoting fragmentation and/or dissociation of at least a portion of the accelerated gas cluster ions along the beam path;
• removing charged particles from the beam path to form an accelerated neutral beam along the beam path in the reduced pressure chamber;
• introducing a patterned template and the substrate into the reduced pressure chamber;
• holding the substrate in the beam path;
• treating a portion of a surface of the substrate by irradiating it through openings in the patterned template with the accelerated neutral beam to form a hardened and/or densified carbon-containing patterned layer on the irradiated portion of the surface by implanting carbon atoms into the irradiated portion of the surface;
• separating the template from the substrate;
• first etching the surface having the carbon-containing patterned layer to preferentially remove material in non-carbon-containing parts of the surface, forming one or more trench(es) and one or more plateau(s);
• forming a hard mask layer over the plateau(s) and trench(es);
• planarizing the hard mask layer to remove it from the plateau(s), but not the trench(es);
• and
• optionally, second etching the surface, using the hard mask layer as a mask to remove substrate material.