Daniel Jasper

NanoLab: A nanorobotic system for automated pick-and-place handling and characterization of CNTs

Carbon nanotubes (CNTs) are one of the most promising materials for nanoelectronic applications. Before bringing CNTs into large-scale production, a reliable nanorobotic system for automated handling and characterization as well as prototyping of CNT-based components is essential. This paper presents the NanoLab setup, a nanorobotic system that combines specially developed key components such as electrothermal microgrippers and mobile microrobots inside a scanning electron microscope. The working principle and fabrication of mobile microrobots and electrothermal microgripper as well as their interaction and integration is described. Furthermore, the NanoLab is used to explore novel key strategies such as automated locating of CNTs for pick-and-place handling and methods for electrical characterization of CNTs. The results have been achieved within the framework of a European research project where the scientific knowledge will be transfered into an industrial system that will be commercially available for potential customers.

Line Scan-Based High-Speed Position Tracking Inside the SEM

Efficient visual servoing using scanning electron microscope feedback is a key challenge for high-throughput nanomanipulation. A novel position tracking approach bypasses image acquisition using dedicated line scans to detect the movement of a nanoobject or reference pattern. With a custom scan generator, update rates over 1 kHz are achieved and objects are tracked with an accuracy up to 10 nm over long travel ranges. Integrated into a microrobotic control infrastructure, the tracking approach facilitates high-speed closed-loop position and trajectory control. Evaluation measurements demonstrate the closed-loop positioning of a nanohandling robot in a few tens of milliseconds paving the way for industrial applications.

Automated high-speed nanopositioning inside scanning electron microscopes

This paper describes a new, automated positioning system that uses the scanning electron microscope as a fast, high-resolution sensor system. With two line scans and low computational overhead, the exact position of a reference pattern is determined. Using a customized external scan generator and scanning algorithm, the bottleneck of image acquisition is bypassed and the position tracking system can reach update rates of 1 kHz. Using imaged-based object recognition algorithms for automated tracking-initialization and a tight integration into the control infrastructure of mobile nanohandling robots, fully automated nanopositioning is possible. A positioning accuracy below 10 nm is achieved in a tungsten cathode-based microscope and positioning operations along well-defined trajectories are completed in a few tens of microseconds.

Automated nanorobotic handling of bio- and nano-materials

Automated handling on the nanoscale is a crucial challenge for commercialization of bio- and nano-technologies. This paper describes current implementations towards two fields of application: Micro-nano integration for NEMS prototyping, and biosensor development. (1) The integration of nanomaterials into micro-systems can improve the properties of such systems and enable novel innovative solutions. Using nanorobotic systems operating inside the vacuum chamber of a scanning electron microscope is a promising approach. Nanorobotic strategies for the microgripper-based handling with focus on automation are presented. A fully automated handling sequence demonstrates the micro-nano integration of prototypic nanotube-enhanced atomic force microscope probes. (2) Nanorobotic systems employing an atomic force microscope are a promising approach for the handling of nanoscopic biomaterials. Methods for the handling of DNA to design bio-nano chips and to solve packaging problems on the nanoscale are presented. Additionally, an AFM-based approach for the structuring of biomaterials is presented.

High-speed position tracking for nanohandling inside scanning electron microscopes

This paper describes a new position tracking system that uses the scanning electron microscope as a fast, high-resolution sensor system. The position tracking system works similar to an optical encoder using a specially structured pattern as scale. Thus, with low computational overhead, an accuracy below 10nm is achieved in a tungsten cathode-based microscope. The tracking system is virtually immune to changes in contrast, brightness, magnification and, to a certain extend, to defocusing. With a customized, external scan generator and scanning algorithm, the bottleneck of image acquisition can be bypassed and the position tracking system can reach update rates of more than 1 kHz. Furthermore, measurements can be conducted over long working ranges of up to 200µm without losing precision.

Automated handling and assembly of customizable AFM-tips

Todays 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 todays 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.

Development, Control and Evaluation of a Mobile Platform for Microrobots

Abstract This paper describes the development, control and evaluation of a mobile platform for microrobots. The platform uses laser-structured piezoceramic plates equipped with ruby hemispheres in order to continuously rotate three steel spheres using the stick-slip effect. The spheres roll on the working surface and can thus move the platform in two translational and one rotational degrees of freedom. This indirect stick-slip actuation does not stress the working surface and can even operate on surfaces that are not perfectly flat. The exact geometry of the actuators is analyzed and an open-loop control approach is derived. As there are 27 piezo segments moving nine ruby hemispheres and three steel spheres, both the amplification hardware and the software algorithms need to be carefully designed. A prototype was built and evaluated to prove the concept. Basic data about the platforms properties such as step length, resolution and actuation speed was gathered. The results are very promising as the platform can move with nm-resolution and with velocities of up to 10mm/s.

Towards automated AFM-based nanomanipulation in a combined nanorobotic AFM/HRSEM/FIB system

In this paper, the semi-automated AFM-based nanomanipulation of silica spheres with a radius of 550 nm is presented. A combined AFM/HRSEM/FIB system is used to facilitate the SEM vision-based pick-and-place handling with haptic feedback. Object recognition and tracking algorithms are described supporting the automated localization of micro-and nanospheres. Automated alignment of source and target sample positions is realized to support fast exchange of different substrates and to speed up the pick-and-place procedure. The integration of a haptic feedback device allows for intuitive AFM-based nanomanipulation with force feedback. The silica spheres are assembled into 2×2 μm arrays for applications in infrared spectroscopy.

Hardware-based, Trajectory-Controlled Visual Servoing of Mobile Microrobots

Abstract Visual servoing based on camera or microscopic feedback has become a widely acknowledged technique for the positioning of robots. With a hardware-based image processing and tracking architecture, classic timing downsides such as low update rates, latency and jitter can be bypassed making visual servoing efficient. Applying this tracking to mobile nanohandling robots, a compact high-performance micro- and nanopositioning system is realized. Trajectory control becomes feasible due to the deterministic timing behavior of the position tracking as well as the reliable open-loop control of the robots. Measurement results demonstrate the excellent characteristics of the CMOS camera-based tracking system, the mobile nanohandling robots and the trajectory-controlled positioning. Although initially aimed at coarse positioning, the system achieves accuracies below 1 ±m.

Laser-Based Structuring of Piezoceramics for Mobile Microrobots

This paper describes the laser-based structuring of piezoceramic actuators used in a mobile microrobot. The actuator has to meet several requirements. Firstly, the achieved positioning accuracy of the mobile platform should be in the single nanometer range. This leads to the use of piezoelectric ceramics, which support this demand. Secondly, as the robot needs to have up to three degrees of freedom (DoF), a complex actuator design is necessary. Thirdly, a small size of the actuator is advantageous in terms of microrobotics. Conventional structuring especially in three dimensions is challenging, due to the refractory properties of piezoceramics and the danger of short circuits or overheating. The presented laser fabrication process uses an Nd-YAG laser and a developed algorithm to structure special actuators. The successful application in a mobile microrobot proves the concept.