Wear-Insensitive Sidewall Microprobe With Long-Term Stable Performance for Scanning Probe Microscopy Lithography

In this paper, a wear-insensitive sidewall microprobe with long-term stable performance is proposed. The proposed microprobe helps to reduce probe-tip wear and improve patterning stability in scanning probe microscopy lithography. The microprobe tip with a uniform cuboid-shape consists of a microscale mechanical contact and two nanoscale electrical contacts formed on the sidewall of the mechanical contact. The microscale mechanical contact reduces tip wear by dispersing the force applied to the tip, while the nanoscale electrical contact enables the sketching of nanoscale features. The uniform shape of the probe tip enables the probe to maintain its stable performance, even when it is mechanically worn. A prototype of the proposed microprobe with an 80-μm long mechanical line contact and a 30-nm long electrical line contact is fabricated using microelectromechanical systems techniques. The patterning stability of the fabricated microprobe in local anodic oxidation (LAO) lithography is investigated in terms of the change in the dimensions of the drawn lines and the shape of the probe tip before and after a 2-m scan. The results of the LAO lithography show that the fabricated microprobe could maintain a stable patterning performance after 2-m scan, which is an improvement of several thousand times over a conventional probe.