Manufacturing Process Optimization of Polycrystaline Aluminum and Aluminum Alloy on SiO2/Si

Abstract

Chlorine-based plasma of BCl3/CCl4 etc. was applied to dry-etch PVD sputtered 1.2µm aluminum alloy with Al-Si-Cu 98%-1%-1%. AZ-1500 resist acted as the etching mask for Al. XRD of alloy with annealing temperature of 300°C, 400°C on TEOS oxide and 20°C, 400°C on silicon, was reported. Etching away Al with bigger grain at the scribe lines, improved the dicing and decreased the cracking. Applying the chemical onto the developed i-line chemical amplified resist further decreased the optical CD to 0.15µm with the reticle CD 0.35µm. Newly obtained mask has the resist thickness of 2-5 µm with the slope of 89°. Oxygen plasma cleaning was applied. Optimized electromigration after high-temperature-annealing with bigger grain decreased both short circuitry (Hilllocks) for Ohmic contact and broken circuitry (Void) for interconnect.