Automated handling and assembly of customizable AFM-tips

Abstract

Abstract-Today's processes in micro-and nanofabrication include several critical dimension metrology steps to guarantee device performance. Especially in the manufacturing process of novel disruptive photonic devices and nanoelectronic circuit architectures, new 3D acquisition and visualization techniques for metrology are required. Two of the most important parameters are the line width and sidewall roughness of vertical interconnects and nanooptical structures. The measurement of these parameters becomes increasingly challenging as the continuous shrinking of dimensions requires higher lateral resolution. The AFM has become a standard and widely spread instrument for characterizing such nanoscale devices and can be found in most of today's research and development areas. However, the characterization of three dimensional high-aspect ratio and sidewall structures is still a bottleneck. Novel exchangeable and customizable scanning probe tips, so-called NanoBits, can be attached to standard AFM cantilevers offering unprecedented freedom in adapting the shape and size of the tips to the surface topology of the specific application. In order to realize the in-situ exchange of NanoBits within the AFM environment the NanoBits have to be provided in a freestanding way that allows the AFM cantilever to be aligned and connected to the NanoBits. Due to the fact that direct microfabrication of such structures is still challenging, a nanorobotic preassembly of NanoBits cartridges is reasonable. These cartridges are intended to contain several NanoBits with a variety of different tip-shapes.

Design of a micro-cartridge system for the robotic assembly of exchangeable AFM-probe tips

“…The robotic system has six degrees of freedom and consists of a coarse positioning unit from SmarAct and a fine positioning unit of PI, allowing to perform fast sample changes as well as accurate movements with nanometer resolution [5].…”

“…Two different configurations were tested for this task: i) a configuration using a gripper with gripping surfaces tilted against the NanoBits and ii) a configuration where the entire gripper is tilted against the NanoBit (cf. [5]). Both approaches work but the latter provides results, which are much more predictable and reproducible.…”

“…This contribution presents developments and improvements of all mentioned components in regard to recent developments. [5].…”

Ultra-high aspect ratio replaceable AFM tips using deformation-suppressed focused ion beam milling

“…Attachment of the exchangeable tip (the nanobit) onto an AFM cantilever is the final, rather delicate operation. We previously demonstrated mounting and scanning of nanobit tips fabricated by electron beam lithography [27,39]. In this approach a nanobit is detached from the source reservoir and attached to the AFM probe either by mechanical insertion into a slit or by gluing via EBID with carbonaceous material [17].…”