Front‐End Processes

In the flow of semiconductor device fabrication the first two phases are defined as front-end processing and the last two phases are defined as back-end processing. This chapter presents the steps of front-end process: cleaning, oxidation, doping, deposition and etching. Wet cleanings are used to reduce metallic and organic contamination before high-temperature steps and thin films deposition, to remove particles from the wafer surface, and to remove sacrificial thin film layers and photoresist. Silicon oxidation is still widely used in advanced IC manufacturing. The chapter reviews some of the main approaches to reduce and control junction depth, increase dopant activation, and increase doping control in nonplanar structures. Methods of depositing thin films for IC manufacturing are usually separated into three major categories: chemical vapor deposition (CVD), physical vapor deposition (PVD), and spin coating. Wet etching has been for a long time the main material removal system in the semiconductor industry.