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Use the SA-AFM for scanning life science samples, large samples, routine scanning of technical samples, or for nanotechnology research. The SA-AFM is a complete system and includes everything required for scanning all sizes and shapes of samples. It is easily integrated with all manufacturer’s inverted microscopes.

• Flexible, stand alone design
• Scans any sample size
• Adaptable to inverted microscopes
• Linearized xy piezoelectric scanner
• Accommodates widest range of standard AFM probes
• All standard modes, including vibrating, non-vibrating, and phase
• Direct drive motorized probe approach
• Intuitive LabVIEW-based software for image capture

Using the industry standard light lever force sensor, all standard scanning modes are included with the system. Vibrating mode is used for high resolution and soft samples, while non-vibrating mode can be used for routine scanning. Also included with the system are phase and lateral force modes.

Control software, written in LabVIEW, is simple and intuitive to use. Differing windows walk users through the process: a pre-scan window helps align the AFM probe, a scanning window aids in acquiring images, a force position window measures force distance curves, and finally, a system window assists in altering system parameters.

SA-AFM Measurements

In addition to measuring surface structure, the SA-AFM is ideal for modes measurements. For example these images are of a polymer sample. The top image is the topography image and the bottom image is the phase image, measuring the relative hardness of the polymer sample.

Surface Texture

Polished Surface - 30x30x5 microns

Surface texture on polished and machined surfaces is readily measured with the SA-AFM. With the SA’s flexible stage design, fixtures for holding almost any sample shape can be created. Once measured, the AFM images can be analyzed and standard surface texture parameters such as Ra are readily calculated.

Dimensional

Calibration reference - 40x40x1 micron

Atomic force microscopes are capable of accurately measuring the dimensions of semiconductor and other micro-fabricated devices. Because the SA-AFM accommodates commercially available AFM probes, specialized probes for metrology measurements can be used.

Visualization

Cells - 8x8 microns. Image measured by Dr. Peter Eaton on the TT-AFM

One of the most powerful capabilities of the SA-AFM is the capability to visualize surface structure. Although not easily quantified, the surface texture of this cell structure is readily visualized. Features that may be readily visualized with the SA-AFM range in size from a few nm to a few microns.

SA-AFM stage

High Resolution Z Stage
The direct drive’s Z stage controls motion down to 330 nm, assuring optimal tip approach. Software controls for the Z stage rapidly move the light lever up and down and regulate the automated probe approach.

Light Lever Force Sensor
An industry standard light lever force sensor is utilized in the SA-AFM. The probe holder accommodates the widest range of commercially available AFM probes. The light lever force sensor can make measurements in standard modes, including vibrating, nonvibrating, lateral force, and phase mode.

Video Microscope
The high resolution video microscope has a zoom tube which allows a field of view between 2 X 2 mm and .3 X .3 mm. The video microscope is essential for aligning the light lever laser, locating features for scanning, and facilitating tip approach.

XY Piezo Scanner
For XY scanning, linearized piezo electric ceramics utilize real time feedback control to assure accurate measurements. The multiple modified tripod design (MMTD) of the xy scanner provides scans with minimal background bow.

Probe holder
A modular probe holder is used in the light lever force sensor and held in place with a spring clip. Probes can be replaced in less than two minutes with the probe exchange tool. Additionally, the probe holder’s spring clip can be used to supply voltages to the AFM probe for techniques such as conductive AFM.

ebox

Electronics in the SA-AFM are constructed around industry standard USB data acquisition electronics. The critical functions, such as xy scanning, are optimized with a 24-bit digital to analog converter. With the analog z feedback loop, the highest fidelity scanning is possible. Vibrating mode scanning is possible with both phase and amplitude feedback using the high sensitivity phase detection electronics.

24-bit Scan DAC
Scanning waveforms for generating precision motion in the X-Y axis with the piezo scanners are created with 24 bit DACS driven by a 32 bit micro controller. With 24 bit scanning, the highest resolution AFM images may be measured. Feedback control using the xy strain gauges assures accurate tracking of the probe over the surface.

Phase and Amplitude Detector Circuit
Phase and amplitude in the Ebox are measured with highly stable phase and amplitude chips. The system can be configured to feed back on either phase or amplitude when scanning in vibrating mode.

Signal Accessible
At the rear of the eBox is a 50 pin ribbon cable that gives access to all of the primary electronic signals without having to open the eBox.

Precision analog feedback
Feedback from the light lever force sensor to the Z piezoceramic is made using a precision analog feedback circuit. The position of the probe may be fixed in the vertical direction with a sample-and-hold circuit.

Variable Gain High Voltage Piezo Drivers
An improved signal to noise ratio as well as extremely small scan ranges are possible with the variable gain high voltage piezo drivers.

Software

Software for acquiring images is designed with the industry standard LabVIEW programming visual interface instrument design environment. Functions such as setting scanning parameters, probe approach, frequency tuning and real time image display are all standard, and included with the product. If special enhancements are needed, LabVIEW’s programming environment facilitates rapid software development. LabVIEW standards ensure that the SA-AFM can be combined with any other instrument using LabVIEW VI.

Image Analysis Software

Included with the SA-AFM is the Gwyddion open source SPM image analysis software. This complete image analysis package has all of the software functions necessary to process, analyze and display SPM images.

• Visualization: false color representation with different types of mapping
• Shaded, logarithmic, gradient- and edge-detected, local contrast representation, Canny lines
• OpenGL 3D data display: false color or material representation
• Easily editable color maps and OpenGL materials
• Basic operations: rotation, flipping, inversion, data arithmetic, crop, re-sampling
• Leveling: plane leveling, profiles leveling, three-point leveling, facet leveling, polynomial background removal, leveling along user-defined lines
• Value reading, distance and angle measurement
• Profiles: profile extraction, measuring distances in profile graph, profile export
• Filtering: mean, median, conservative denoise, Kuwahara, minimum, maximum, checker pattern removal
• General convolution filter with user-defined kernel
• Statistical functions: Ra, RMS, projected and surface area, inclination, histograms, 1D and 2D correlation functions, PSDF, 1D and 2D angular distributions, Minkowski functionals, facet orientation analysis
• Statistical quantities calculated from area under arbitrary mask
• Row/column statistical quantities plots
• ISO roughness parameter evaluation
• Grains: threshold marking and un-marking, watershed marking
• Grain statistics: overall and distributions of size, height, area, volume, boundary length, bounding dimensions
• Integral transforms: 2D FFT, 2D continuous wavelet transform (CWT), 2D discrete wavelet transform (DWT), wavelet anisotropy detection
• Fractal dimension analysis
• Data correction: spot remove, outlier marking, scar marking, several line correction methods (median, modus)
• Removal of data under arbitrary mask using Laplace or fractal interpolation
• Automatic xy plane rotation correction
• Arbitrary polynomial deformation on xy plane
• 1D and 2D FFT filtering
• Fast scan axis drift correction
• Mask editing: adding, removing or intersecting with rectangles and ellipses, inversion, extraction, expansion, shrinking
• Simple graph function fitting, critical dimension determination
• Force-distance curve fitting
• Axes scale calibration
• Merging and immersion of images
• Tip modeling, blind estimation, dilation and erosion

Video Microscope

A video optical microscope in an AFM serves three functions: aligning the laser onto the cantilever in the light lever of the AFM, locating surface features for scanning, and facilitating probe approach. The SA-AFM includes a high performance video optical microscope along with a 3 mega pixel CCD camera, light source, microscope stand, and Windows software for displaying images.

	The video microscope is used to locate surface features for scanning. The vibrating mode probe cantilever shown here is 125 microns long. The sample is a reference for conductive mode AFM which has several electrodes that come together in the center.
	Laser alignment is greatly facilitated with the video optical microscope. With a resolution of 1.5 it is possible to directly visualize the position of a laser spot on the cantilever. The video optical microscope is also used to increase the rate of probe approach. It is possible to estimate the distance between a sample and probe by focusing first on the sample and then on the probe.

Probe Holder/Exchange

The SA-AFM utilizes a unique probe holder/exchange mechanism. Probes are held in place with a spring device that mates with a probe exchange tool. This combination makes changing probes fast and easy on the SA-AFM.

MODES

Standard with every SA-AFM are nonvibrating (NV) mode and vibrating (V) modes for creating topography scans. Additional modes included with the product are lateral force imaging and phase mode imaging. Any scanning mode that can be implemented with a light lever AFM is possible with the SA-AFM.

With the window above the resonance frequency of a cantilever is readily measured. Additionally, the phase characteristics of the probe-sample interaction may be captured.

SPECIFICATIONS

Video Microscope

Computer

• Industry Standard Computer & Monitor (laptop available upon request)
• Windows 7
• AFMWorkshop LabVIEW .exe installed

Stage

Back and side view of the SA-AFM stage without the AFM/video microscope. The feet at the bottom may be removed if the stage is rigidly mounted to a surface.

* Z Noise performance depends greatly on the environment in which the SA-AFM is used. Best Z noise performance is obtained in a vibration free environment.

** Every effort is made to present accurate specifications; however, due to circumstances out of the AFM Workshop’s control, specifications are subject to change.