In-line metrology for atomic resolution local height variation

We demonstrated fully automated in-line atomic force microscopy (AFM) for local height variation monitoring solution. Two use cases, which are local variation of SADP Fin height and oxide recess height in Fin reveal process and that of Cu nail protrusion and Cu pad recess height 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.