With the rapid evolution of microelectronics and nanofabrication technologies, the critical feature sizes of large-scale integrated circuits continue to move toward the nanoscale. There is a strong need to improve the quality and efficiency of integrated circuit inspection, but it remains a great challenge to provides both rapid imaging and circuit node-level high-resolution images simultaneously using a conventional microscope.

A research team led by Lianqing Liu from the Shenyang Institute of Automation (SIA) of the Chinese Academy of Science (CAS) proposed a nondestructive, high-throughput, multiscale correlation imaging method that combines AFM with microlens-based scanning optical microscopy.

Liu's team coupled the microlens with an AFM probe and depositing a scanning tip on the microlens surface facing the sample, microlens-based optical imaging and AFM can be combined and the AFM force feedback mechanism can enable accurate control of the spatial position of the microlens during scanning and imaging. Three imaging modes are realized: fast and high-throughput scanning optical imaging with microlens, AFM imaging of surface fine structure, and microlens-AFM simultaneous imaging.

Experimental results verified that the introduction of a microlens improves the imaging resolution of the conventional AFM optical system with a 3–4× increase in imaging magnification, effectively bridging the resolution gap between traditional optical imaging and AFM. The imaging throughput is improved ~8× compared to a commercial AFM. High-throughput and high-resolution correlative AFM and scanning superlens microscopy achieves cross-scale rapid imaging with micron to nanometer resolution and improves the efficiency of AFM-based large-scale imaging and detection.

Their study was published online in Advanced Science on February 28.