US 6,608,307 B1Granted

System and method for accurate positioning of a scanning probe microscope

AssigneeZyvex Corporation

InventorChristof Baur

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Abstract

A system and method provide three-dimensional real time stabilization of the gap between probe tip and sample in a scanning probe microscope (SPM) against creep and drift. Supplemental signals in each axis provide supplemental movement to the probe tip to offset drift. The supplemental signals can be applied simultaneously or sequentially in any combination of axes. Typically the supplemental signals are determined from calculated drift predictions, based on drift measurements inferred from feedback in response to the gap-dependent strength of an interaction between probe and sample. Waveform modulation is coupled into the drive circuitry for each axis, and a waveform-synchronous feedback signal is extracted and processed to measure drift. The waveform modulations can be identical or asynchronous and applied sequentially or simultaneously in any combination of axes. An algorithm performs the process in real time.

Claims23

Dependent claims

In a scanning probe microscope (SPM), a method of stabilization in real time of the gap separating probe tip and sample in at least two intersecting axes, at least one of said at least two intersecting axes being substantially non-parallel to the scan pattern of said SPM, said method providing supplemental movement in said at least two intersecting axes to said probe tip to offset drift motion of said probe tip relative to said sample, said method comprising the steps of:

a. applying a first supplemental signal which provides supplemental movement in a first axis of said at least two intersecting axes to said probe tip in conjunction with a first positioning signal in said first axis of said at least two intersecting axes;
and
b. applying a second supplemental signal which provides supplemental movement in a second axis of said at least two intersecting axes to said probe tip in conjunction with a second positioning signal in said second axis of said at least two intersecting axes;
wherein
said steps of applying a first supplemental signal and applying a second supplemental signal include providing supplemental signals which provide a controlled movement of said probe tip that offsets drift motion of said probe tip relative to said sample in said at least two intersecting axes;
and
wherein said supplemental signals are determined in response to a topographic signal.

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