| 摘要 |
A caliper atomic force microscope (AFM) comprises two AFM probes (each comprised of an oscillator and an attached tip) that operate on a sample in a coordinated manner. The coordinated operation of the AFM probes may be spatially or temporally coordinated. The result of the coordinated operation may be an image of the sample or a dimensional measurement of an unknown sample. The probes of the caliper AFM may be tilted, or the tips may be tilted at a non-orthogonal angle with respect to the probes, so as to enable the tips to access vertical sample surfaces or to enable the tips to touch each other. The tip shapes may include conical, boot-shaped, cylindrical, or spherical and materials from which the tips are fabricated may include silicon or carbon nanotubes. The oscillators may be beveled to allow the tips to operate in close proximity or in contact without interference of the oscillators. The disclosure of the present invention is discussed in terms of an atomic force (van der Waalls) interaction. Other interaction forces are contemplated, such as electrostatic force, magnetic force, and tunneling current. The caliper AFM may be calibrated with the help of a sample with known dimensions or by touching the probe tips. The tip-to-tip calibration enables absolute measurements without the need for a reference artifact, and it enables in-line calibration that may be performed during the measurement process.
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