Measurement and characterization of small defects on large areas are time consuming but can be accelerated using high speed cameras and GPGPUs (general purpose graphic processing units). A height map of a filter glass with a 50 mm diameter scanned with a spatial sampling of 1 μm must present the data of more than 1000 single scans or 2.5 billion measuring points on a screen. Stitching processes of such data amount exceed the capacity of actual available metrology software packages even while operating on high end PCs. Resampling processes may result in a loss of information about surface roughness and small defects. Batch processing of the single scans is possible but make the interpretation of measuring results complicate and time consuming. Task specific data processing strategies overcome the given limitations. Disturbing residual stitching errors in overlapping zones are avoided and small scratches can still be observed in 3d maps of the complete sample. This simplifies the localization and provide information for preventive measures. Similar but adapted processing strategies are available to visualize local fluctuations of the surface textures. Test was done using the optical profiler smartWLI firebolt. The sensor operates on the measuring principal CSI - coherence scanning (white-light) interferometry and uses a 1.3 MP camera with 935 fps / full resolution. Data are processed in real time using a CUDA programmable NVIDIA graphic board which provides a calculation power of up to 82.6 FP32-TFLOPs. Thus, resulting in acquisition performance of up to approximately 1 single scan per second.
Nanopositioning and nanomeasuring machines (NPM machines) developed at the Ilmenau University of Technology
allow the measurement of micro- and nanostructures with nanometer precision in a measurement volume of
25 mm × 25 mm × 5 mm (NMM-1) or 200 mm × 200 mm × 25 mm (NPMM-200). Various visual, tactile or atomic force
sensors can all be used to measure specimens. Atomic force sensors have emerged as a powerful tool in nanotechnology.
Large-scale AFM measurements are very time-consuming and in fact in a practical sense they are impossible over
millimeter ranges due to low scanning speeds. A cascaded multi-sensor system can be used to implement a multi-scale
measurement and testing strategy for nanopositioning and nanomeasuring machines. This approach involves capturing an
overview image at the limit of optical resolution and automatically scanning the measured data for interesting test areas
that are suitable for a higher-resolution measurement. These “fields of interest” can subsequently be measured in the
same NPM machine using individual AFM sensor scans.
The results involve extremely large data sets that cannot be handled by off-the-shelf software. Quickly navigating within
terabyte-sized data files requires preprocessing to be done on the measured data to calculate intermediate images based on the principle of a visualization pyramid. This pyramid includes the measured data of the entire volume, prepared in the form of discrete measurement volumes (spatial tiles or cubes) with certain edge lengths at specific zoom levels. The functionality of the closed process chain is demonstrated using a blob analysis for automatically selecting regions of interest on the specimen. As expected, processing large amounts of data places particularly high demands on both computing power and the software architecture.
Due to the development and progress in micro- and nanotechnology the range of measuring tasks is becoming ever more
varied and multifaceted. Decreasing structure widths in combination with large area measurements or complex 3D-micro-
and nanostructures with high aspect ratios not only on flat but also on curved surfaces are some of these
measurement challenges. In order to solve the problems arising within this application spectrum a multi-sensor platform
based on a laser focus probe was developed. This platform is integrated in the Nanopositioning and Nanomeasuring
Machine developed mainly at the Institute of Process Measurement and Sensor Technology at the Ilmenau University of
Technology with a measuring range of 25 mm x 25 mm x 5 mm and subnanometre resolution.
The paper focuses on the utilization of nanopositioning and nanomeasuring machines as a three dimensional coordinate
measuring machine by means of the international harmonized communication protocol Inspection plus plus for
Dimensional Measurement Equipment (abbreviated I++DME). I++DME was designed 1999 to enable the
interoperability of different measuring hardware, like coordinate measuring machines, form tester, camshaft or
crankshaft measuring machines, with a priori unknown third party controlling and analyzing software.
Our recent work was focused on the implementation of a modular, standard conform command interpreter server for the
Inspection plus plus protocol. This communication protocol enables the application of I++DME compliant graphical
controlling software, which is easy to operate and less error prone than the currently used textural programming via
MathWorks MATLab.
The function and architecture of the I++DME command interpreter is discussed and the principle of operation is
demonstrated by means of an example controlling a nanopositioning and nanomeasuring machine with Hexagon
Metrology's controlling and analyzing software QUINDOS 7 via the I++DME command interpreter server.
KEYWORDS: Point spread functions, Deconvolution, Scanning probe microscopy, Microscopy, Convolution, Microscopes, Data modeling, Chemical elements, Image processing, Analytical research
The Kelvin Probe Force Microscopy (KPFM) is a method to detect the surface potential of micro- and nanostructured
samples using a common Scanning Probe Microscope (SPM). The electrostatic force has a very long
range compared to other surface forces. By using SPM systems the KPFM measurements are performed in the
noncontact region at surface distances greater than 10 nm. In contrast to topography measurement, the measured
data is blurred. The KPFM signal can be described as a convolution of an effective surface potential and a
microscope intrinsic point spread function, which allows the restoration of the measured data by deconvolution.
This paper deals with methods to deconvolute the measured KPFM data with the objective to increase the
lateral resolution. An analytical and a practical way of obtaining the point spread function of the microscope
was compared. In contrast to other papers a modern DoF-restricted deconvolution algorithm is applied to the
measured data. The new method was demonstrated on a nanoscale test stripe pattern for lateral resolution and
calibration of length scales (BAM-L200) made by German Federal Istitute for Materials Research and Testing.
This article presents white light interferometry as a new application for the nanopositioning and nanomeasuring machine
(NPMM). The NPMM was developed under the leadership of the Institute of Process Measurement and Sensor
Technology at the Technische Universität Ilmenau (Germany) and allows highly exact dimensional and traceable
positioning with a resolution of 0.1 nm within a volume of 25 mm x 25 mm x 5 mm.
An application of white light interferometry was developed on the basis of these features which can utilize the device's
very high precision and large effective range, which enables the stitching of partitioned results without overlapping
measurements and expensive matching methods.
In order to extract height data from the interferograms, a robust, precise and fast method using matched filters in the
frequency domain has been put into practice. The filter templates are calculated according to a model function or are
directly sampled from the light source power spectrum, which has been previously analyzed once. Thus, light sources
with different spectral forms can be used.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.