Introduction
The Light Lever AFM (LL-AFM) Scanner is an option for the Pacific Nanotechnology Nano-R™ and Nano-I™ SPM stages. The LL-AFM is ideal for visualizing nano-scale surface features and making mode measurements such as lateral force microscopy or phase imaging. The LL-AFM measures the force between a probe at the end of a microscopic cantilever by monitoring the reflection of a laser beam off the back side of the cantilever.
Several advanced features in the LL-AFM scanner simplify its operation. The LL-AFM uses the patented hollow pivot design which facilitates a direct view of the cantilever with a high resolution video optical microscope making it easy to align the force sensor and locate features for scanning. Further, adjusting the LL-AFM sensor system is easily achieved using controls at the front of the scanner. With the rapid probe exchange mechanism, placing new probes in the scanner is relatively simple.
Several options are available for the LL-AFM including LPM Software for doing nano-scale lithography, electrical probing, and move & scan measurements. With the environmental cell, this tip scanning LL-AFM can be used in many types of environments. Most types of commercially available probes can be used in the LL-AFM Scanner
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XYZ Calibration Sensors
The LL-AFM scanner has calibration sensors in the X, Y, and Z axes. The calibration sensors assure precise and accurate images. Also, sensors make zooming to a feature in an AFM very efficient. As an example, shown here is a case in which a defect was visualized on the surface of a DVD. Zooming in for a higher resolution scan required only one zoom step with the LL-AFM.
With the calibration sensors, making accurate and precise measurements is possible. In the X-Y scan directions, the calibration sensors are used in closed loop to create linear motions. In the Z axis, the calibration sensors are used to directly measure the motion of the probe as it is scanned across a surface.
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Probe Exchange
The LL-AFM Scanner is compatible with the Nano-R™ and Nano-I™ SPM stages. Both of these stages offer simple probe exchange mechanisms that facilitate probe exchange without having to remove the head from the stage.
Both the Nano-R™ and the Nano-I™ stages have rapid release mechanisms that can be unlatched in a matter of seconds. The scanner can then be rotated so that the probe can be exchanged. Typically the probe is mounted on a metal substrate that is held in place with a magnet. Changing probes takes only a minute or two with the PNI LL-AFM Scanner.
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Accessible Adjustments
After a probe is changed in the LL-AFM Scanner, the light lever optics must be adjusted. This process is simplified because the adjustment knobs are at the front of the scanner. Also, the high resolution video optic helps detect the exact location of the laser spot on the cantilever.
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Universal Probe Holder
The LL-AFM Scanner uses a magnetic hold down mechanism for securing the cantilever/probes in the microscope. The probes may be pre-mounted on a metal substrate, or a clip mechanism may be used. When a new mechanism is required, as in the Environmental Cell option, a mounting block is available. To change the probe mount, two screws are removed and the alternative probe holding mechanism is used.
The Universal probe holder on the LL-AFM Scanner is designed so that many types of probe mounts can be used. Shown here is the standard probe holder that is supplied with the LL-AFM Scanner. In this design, the AFM probe/substrate is mounted on a metal plate and the metal plate is held in place with magnets. The probe holder is changed by removing only two screws, illustrated in the photo.
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Optical View
In the LL-AFM or CFM Scanner, a direct optical view of the cantilever is possible. The direct optical view, in combination with a video optical microscope, is useful for aligning the laser onto the cantilever. Also, with the video optical microscope, finding features for scanning is facilitated. The PNI SPM systems have video microscopes that have maximum magnification of 1000X and a resolution of 1.5 μ.
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Applications
The LL-AFM Scanner may be used for a diverse number of applications including imaging nanostructures, polymers, micro/nano fabricated devices, life sciences samples, and industrial samples. Additionally, the LL-AFM can be used for many imaging modes such as LFM and Phase Imaging.
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Red Blood Cells
20 x 20 μ |
Breast Cancer Cells
78 x 78 μ |
PhotoResist Surface
1 x 1 μ |
Patterned PolyPeptides
87 x 87 μ |
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Super Alloy Metal
59 x 59 μ |
Atomic Terraces
1 x 1 μ |
Gold Pattern on Glass
76 x 76 μ |
Polymer Spheres
1.4 x 1.4 μ |
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Laser Texture Bump
16 x 16 μ |
Paper Carbonate / Eucalyptus Fibers
60 x 60 μ |
Vulcanized Rubber Phase
1.3 x 1.3μ |
Vulcanized Rubber
Topography
1.3 x 1.3 μ |
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Abalone Shell
20 x 20 μ |
Carbide Nanoparticles
2.8 x 2.8 μ |
Ni Nanoparticles
2.8 x 2.8 μ |
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