Using a nondestructive in-line system to monitor ultrashallow junctions

摘要

A novel optical metrology technique designed for leading technology nodes can measure junction depth, amorphous layer thickness, and dose. Semiconductor manufacturers face significant process control and metrology challenges as devices reach The International Technology Roadmap for Semiconductors (ITRS) technology nodes of 180 nm and below.1 In addition to the copper damascene processes that have been adopted for the creation of metal interconnects—the control of which was the focus of the first article in this series—newfront-end-of-line (FEOL) processes are being used to form the sensitive extension implants referred to as ultrashallow junctions (USJs). USJs are thin, highly doped regions that connect the channel under a gate to the source and drain regions of the transistor.