A Study on the Bromine-induced Corrosion/Defects in Wafer Fabrication

: For the semiconductor manufacturing processes, metal corrosion by halogen elements (e.g. fluorine, chlorine, and bromine) is always a critical issue. For the aluminum back-end-of-processes, these halogen elements tend to form aluminum halide defects on the surface of aluminum pads or aluminum metal wires, which can directly lead to the failure and reliability issues of the devices. While there have been some reports on the analysis and mechanisms of fluorine and chlorine pollution and their aluminum halide defects, there is a lack of research on the analysis and mechanism studies of bromine (Br) contamination and its associated aluminum bromide defects. In this work, we conducted the comprehensive study on Br-induced Al metal corrosion using Auger electron spectroscopy, scanning electron microscope and energy dispersive spectroscopy (SEM and EDS. Our study indicated that the Br-induced defects primarily consist of aluminum tribromide (AlBr3) and aluminum oxobromide (AlXBrYOZ), which are formed through a series of physical and chemical reactions. We propose a chain chemical reaction mechanism that is closely linked to the chemical corrosion processes induced by bromine.