In-line Atomic Resolution Local Nanotopography Variation Metrology for CMP Process

We demonstrated fully automated in-line atomic force microscopy (AFM) as local nanotopography variation metrology for CMP process control. Two use cases, which are Fin CMP process in SADP Fin process and Cu pad CMP process in wafer-to-wafer hybrid bonding process were evaluated in order to evaluate in-line AFM capability as a metrology solution for process development and in-line process monitoring. In-line AFM provides not only visual information of nanotopography, which could lead to quick decision making, but also to quantitative information of local height variation where other metrology solutions could not have provided. In-line AFM could provide many advantages, which are nondestructive measurement, sub-nanometer accuracy and long term reliability. Those advantages help learning cycle and process quality to enhance. Keywords: In-line metrology, Atomic force microscopy, Nanotopography, Local variation, Logic, FinFET, 3D interconnect, Wafer-to-wafer hybrid bonding, High density carbon tip, Process control