High-aspect-ratio via-hole filling with aluminum melting by excimer laser irradiation for multilevel interconnection

This letter presents a technique for filling via holes on integrated circuits. The filling is achieved by momentarily melting an aluminum film with an optical pulse from an ArF excimer laser. This technique has been shown to allow excellent via filling without damaging lower levels of interconnect, and is applicable to filling submicrometer-diameter vias having a diameter of 0.6 µm with 0.7 µm depth (aspect ratio ∼1.2). The resulting surface was found to be planarized.