Chemical-Mechanical Planarization of Aluminium Damascene Structures

An aluminium damascene process is applied for the fabrication of buried tri-gate structures which are used as substrates for the investigation of novel channel materials for emerging field-effect transistors. The Al-CMP process with a commercial high performance slurry and post-cleaning system was optimized targeting at minimized dishing and erosion as well as realizing non-contaminated, smooth surfaces without the use of any stop layers. Large crystallites at the surface of the Al structures, so-called hillocks, appear immediately after the CMP-process, but remain stable in size over a long time. First experiments with InAs-nanowires demonstrate the applicability of the tri-gate structures with buried Al. Keywords: Aluminium CMP, Aluminium Damascene Structures, Buried Tri- Gate Structures, Novel Channel Materials, InAs-Nanowires, Hillock Growth