# NPS6D200--A Long Range Nanopositioning Stage with 6D Closed Loop Control
## 5 Conclusions and Outlook  
The developed long-range nanopositioning system NPS6D200 follows a comprehensive design approach that focuses on direct force application in combination with aerostatic guiding and laser interferometer feedback. The analysis of the system's positioning capabilities confirms the design approach and shows that within the operating range of \(\diameter 200\,\mathrm{mm}\times 25\,\mathrm{mm}\) positioning with nanometer stability and sensitivity is attained. The system's main limitation is the lack of active angular positioning within the rotational DOFs and, thus, no possible stage slider inclination. The NPS6D200 positioning system obtains servo errors in the low-nanometer range both in constant setpoint operation and in synchronized multiaxial motion. This is achieved in a large operating range and along with very low heat emission and minimized disturbance introduction into the measurement volume. With this combination, the NPS6D200 is well suited as a positioning platform for nanotechnology research applications that on the one hand require such precise and deterministic position control between tool and substrate up to wafer-size and that on the other hand rely on minimized disturbance entry into the area of interaction. Such applications are for example wafer-based inspection, long-range atomic force microscopy scans, and sub-10 nm nanofabrication techniques, to name but a few. In general the architecture approach is scalable and realisations with larger operating ranges are possible. Regarding the planar operation range, the slider size would increase accordingly and this needs to be addressed by a lightweight design of the slider in order to reduce the moving mass and maintain sufficiently high eigenfrequencies. The vertical movement is based on the lifting modules (LAUs) and the coil-lift functionality and a \begin{table}
\begin{tabular}{l l l l} \hline
**Command** & **RMS Servo Errors** & \
\begin{tabular}{l} **RMS Currents** \\ **(Planar Coils)** \\ \end{tabular} &
\begin{tabular}{l} **RMS Currents** \\ **(Lifting Modules)** \\ \end{tabular} \\ \hline \(\diameter 40\,\mathrm{nm}\times 20\,\mathrm{nm}\) & \(e_{x}=0.71\,\mathrm{nm}\) & \(i_{\mathrm{A}}=6.39\,\mathrm{mA}\) & \(i_{\mathrm{I}}=0.5\,\mathrm{mA}\) \\ \(v=\)7\(\,\mathrm{nm}\,\mathrm{s}^{-1}\) & \(e_{y}=0.88\,\mathrm{nm}\) & \(i_{\mathrm{B}}=27.28\,\mathrm{mA}\) & \(i_{\mathrm{I}}=0.51\,\mathrm{mA}\) \\  & \(e_{z}=0.39\,\mathrm{nm}\) & \(i_{\mathrm{C}}=11.04\,\mathrm{mA}\) & \(i_{\mathrm{I}}=0.46\,\mathrm{mA}\) \\ \hline \(\diameter 40\,\mathrm{\SIUnitSymbolMicro}\times 50\,\mathrm{\SIUnitSymbolMicro}\) & \(e_{x}=2.36\,\mathrm{nm}\) & \(i_{\mathrm{A}}=6.61\,\mathrm{mA}\) & \(i_{\mathrm{I}}=0.5\,\mathrm{mA}\) \\ \(v=\)7\(\,\mathrm{\SIUnitSymbolMicro}\,\mathrm{\SIUnitSymbolMicro}\) & \(e_{y}=2.66\,\mathrm{nm}\) & \(i_{\mathrm{B}}=27.41\,\mathrm{mA}\) & \(i_{\mathrm{I}}=0.51\,\mathrm{mA}\) \\  & \(e_{z}=0.49\,\mathrm{nm}\) & \(i_{\mathrm{C}}=11.29\,\mathrm{mA}\) & \(i_{\mathrm{I}}=0.46\,\mathrm{mA}\) \\ \hline \(\diameter 40\,\mathrm{mm}\times 5\,\mathrm{mm}\) & \(e_{x}=0.93\,\mathrm{nm}\) & \(i_{\mathrm{A}}=50.32\,\mathrm{mA}\) & \(i_{\mathrm{I}}=5.15\,\mathrm{mA}\) \\ \(v=\)7\(\,\mathrm{mm}\,\mathrm{s}^{-1}\) & \(e_{y}=1.66\,\mathrm{nm}\) & \(i_{\mathrm{B}}=74.71\,\mathrm{mA}\) & \(i_{\mathrm{I}}=5.71\,\mathrm{mA}\) \\  & \(e_{z}=0.67\,\mathrm{nm}\) & \(i_{\mathrm{C}}=67.45\,\mathrm{mA}\) & \(i_{\mathrm{I}}=4.56\,\mathrm{mA}\) \\ \hline \end{tabular}
\end{table} 
Table 7: Summarized results of helix trajectory tracking exercises. Figure 13: 3D motion exercise with a \(\diameter 40\,\mathrm{nm}\) helix. \((left)\)—plot of the 3D position signals. \((right)\)— servo error time series in the 6 DOFs during trajectory motion. redesign of both subsystem to a larger vertical stroke is feasible. Based on the achieved performance in 25 mm, a similar positioning performance in sub-10 nm range can be expected also for larger vertical positioning ranges.