The resist-core spacer patterning process for fabrication of 2xnm node semiconductor devices

The spacer patterning process is one of the strongest double patterning technology candidates for fabricating 2xnm node semiconductor devices by ultra-low-k1 lithography. However, a severe problem exists with this process, it has an excessive number of steps, including resist patterning, core film etching, spacer film deposition, spacer film etchback, core film removal, and hard mask patterning steps. We devised a simpler process in which a resist pattern is directly used as the core film pattern and the spacer film is a low-temperature-deposited oxide film that can be fabricated around the resist pattern without damaging the resist material. Thus, this new process, which we call "resist-core" spacer patterning, has significantly fewer patterning steps. When we used the new process to fabricate 2xnm node semiconductor devices with an ArF immersion scanner, two key issues arose. The first issue regarding the controllability of the resist pattern profile, which can directly affect the spacer film pattern profile, was addressed by applying various resist patterning conditions such as resist materials, illumination conditions, and bottom anti-reflecting materials. The second issue, regarding the resist slimming method was addressed by evaluating two alternative techniques, wet slimming and dry slimming.