## 3 Setup of the Planar Nanopositioning Machine  
The newly developed planar nanofabrication machine has been specially designed for measurement and fabrication processes on wafer sizes of 4 inches. Figure 1 shows a side view of the machine setup itself. As mentioned, a tip-based measuring system is installed as a measuring tool. This AFM system uses active microcantilevers and has a three-dimensional motion range of 10 um \(\times\) 10 um \(\times\) 5 um due to the piezo scanning unit. These self-actuated and self-sensing microcantilevers are induced to oscillate by a thermomechanical actuator. This actuator consists of different layers with different coefficients of thermal expansion. The deflection readout of the cantilever is realised by a Wheatstone bridge. Scanning speeds of up to 50 um/s have already been demonstrated with this tip-based system [20]. The whole setup is operated in a climate-controlled and vibration-isolated environment. The slider is guided aerostatically on three air bearings from NewWay [21]. The position is measured by differential interferometers (IFM) [22]. The length measuring systems as well as the actuators are arranged in a single plane and at an angle of 120 degrees between each other, as can be seen in Figure 2.  
Aerostatic guide elements were chosen for the demanding nanometre-precise positioning because they provide a number of advantages, such as extremely low friction and low vibration during the movement [21]. These elements are mounted to the machine slider and hover on the planar granite base of the NFM-100 (see Figure 3), supplied with pressurised air by flexible tubing. Because there is no mechanical contact with this type of guidance, stick-slip effects can be eliminated. In addition, these air bearings are characterised by high repeatability [23]. For positioning of the slider, the NFM-100 uses a planar direct drive system. Three actuators based on electromagnetic force generation are used here, which enable a contactless force transfer. Each actuator consists of two fixed coils that act on magnets attached to the slider, i.e., the machine table. The drive forces of the three linear actuators act simultaneously on the slider. The 120\({}^{\circ}\) arrangement allows a resulting force in any direction within the \(x\)-\(y\) plane and additionally a rotation around the \(z\) axis can be generated [24]. Accordingly, this results in a circular range of motion. Three differential plane-mirror interferometers, which offer especially high thermal stability due to their symmetric optical design, are used as length measurement systems [22]. The laser source for these differential interferometers is a stabilised He-Ne laser, which provides a relative frequency stability of 2 \(\times\) 10\({}^{-8}\). The evaluation electronic uses an arctan demodulation technique with a path resolution of 5 pm [25]. By setting up the interferometers with an external reference beam, the measurement systems can be placed at a greater distance from the measurement location without significantly affecting the stability of the measurement [22]. In contrast, disturbances along the direction of measurement can be partially compensated by the differential design and, thus, noise in the length signal caused by air turbulence or vibrations can be cancelled out to a large extent. Figure 1: Side view of working principle of the planar nanopositioning machine and the installed tip-based system. Figure 2: Mechanical and interferometer set-up of the NFM-100. The position of the slider is tracked by three laser-interferometers in a 120\({}^{\circ}\) arrangement. The slider is driven by three linear actuators, which consist of two flat coils and a magnet array each (magnet array not shown here). (Figure leaned on [11]). In the NFM-100, two interferometers are used for length measurement, while the third interferometer is used for angular measurement.