Micro object handling under SEM by vision-based automatic control

Abstract

There is a great demand for the highly accurate and reliable arrangement of micro objects smaller than 100 p in order to construct micro devices. Since micro objects tend to adhere to other objects by electrostatic force, it is possible to pick them up easily by contact with a needle tip instead of grasping by tweezers. On the other hand, it is difficult to place them on a substrate. To solve this problem, we have proposed a handling method by controlling the contact face area, i.e. picking up the object by contact with the center of the tool-tip plane, and placing it by contact with the edge and also inclining the tool. However, it is difficult to execute this operation by manual control, because it requires delicate movement by the manipulator, in order not to break the object or flip it away. In this study, we automate this pick-andplace operation by visual and force control. Moreover, to arrange micro objects with high accuracy and reliability, all necessary functions such as calibration, object search, and positioning are integrated, and an automatic handling system is constructed. We successfully demonstrated a completely automatic arrangement of several micro objects of 30 pn in diameter under SEM monitoring.

Contact detection for nanomanipulation in a scanning electron microscope

“…Earlier methods of obtaining depth information involved mounting optical microscopes to the side of the SEM sample chamber [34]. In this configuration, XY-positioning information is provided by SEM imaging while Z-positioning feedback is provided by the optical microscope, however, the need for additional hardware and the small depth of focus in optical microscopy complicates the nanomanipulation process.…”

Recent advances in nanorobotic manipulation inside scanning electron microscopes

“…A number of nanorobotic manipulation systems have been constructed for operation inside an SEM since the 1990s 8,13,22 . Hatamura and Tomomasa pioneered the development of a nanomanipulation system inside an SEM [23][24][25] . The system consisted of two manipulators, a controllable base, a customized force sensor, joy sticks, and an optical microscope, which enabled haptic and position control.…”

“…The system consisted of two manipulators, a controllable base, a customized force sensor, joy sticks, and an optical microscope, which enabled haptic and position control. Automated pick-and-place of 30 μm spheres inside an SEM was demonstrated 24 . The system was only capable of manipulating relatively large micrometer-sized objects and was not capable of performing complex assembly tasks owing to the mechanical wobbling of the manipulators and relatively large end-effectors.…”

Effect of alignment angle on the alignment accuracy of a miniature rotation robot for microscopy imaging

“…Also samples are likely to move out of microscope's field of view (FOV) during rotation. The second method is to install multiple microscopy cameras simultaneously, such as assembling an optical microscope, installing a miniature chargable-coupled device (CCD) camera on the lateral side of the SEM chamber, 14,15 and integrating three optical microscopes together. 16,17 Nevertheless, vision from other directions is still not available, and it is difficult to keep samples on good focus for all the microscopic cameras at high magnification.…”