Automated landing method of a scanning probe microscopy system and scanning probe microscopy system using the same
The present disclosure relates to a method of operating an SPM system including a landing procedure. The landing procedure comprises a first landing stage including a first translation over a first actuation distance by a coarse translation means to bring a probe tip held by an SPM head from an initial separation from a substrate to be probed to a second, more proximal, separation as defined by a characteristic transitional response of the probe tip in proximity to the substrate. Following the first stage a second translation is applied, over a second actuation distance by a fine translation means under feedback control to bring the probe tip to a working separation. Prior to applying the first (coarse) actuation distance an initial optical distance is determined which is indicative of the initial separation, using a detector, preferably a mark sensor. The measured initial optical distance is related to a reference distance so as to determine a deviation. The first actuation distance corresponds the reference distance and the deviation. The disclosure also relates to an SPM system and software product arranged to implement the landing method.
1 . A method of operating a scanning probe microscopy (SPM) system comprising a landing procedure comprising:
a first landing stage including: applying a first translation over a first actuation distance by a coarse translation means to bring a probe tip held by an SPM head from an initial separation from a substrate to be probed to a second, more proximal, separation as defined by a characteristic transitional response of the probe tip in proximity to the substrate,
a second landing stage including: applying a second translation, following the first translation, over a second actuation distance by a fine translation means under feedback control to bring the probe tip to a working separation, and
measuring an initial optical distance, indicative of the initial separation, using a detector, and
relating the measured initial optical distance to a reference distance so as to determine a deviation;
wherein, the first actuation distance corresponds the reference distance and the deviation.
2 . The method according to claim 1 , wherein measuring the optical distance using the detector comprises determining a focusing condition of an optical distance sensor provided to the SPM head.
3 . The method according to claim 2 , including a prior calibration routine to determine the reference distance, said routine including:
measuring a reference optical distance associated with the probe tip held by the SPM head positioned at a reference separation from a reference, and
determining the reference distance as defined by a recorded actuation distance required to bring the probe tip from the reference separation to a second, more proximal, reference separation as defined by an observed characteristic transitional response of the probe tip in proximity to the reference.
4 . The method according to claim 1 , including a prior calibration routine to determine the reference distance, said routine including:
measuring a reference optical distance associated with the probe tip held by the SPM head positioned at a reference separation from a reference, and
determining the reference distance as defined by a recorded actuation distance required to bring the probe tip from the reference separation to a second, more proximal, reference separation as defined by an observed characteristic transitional response of the probe tip in proximity to the reference.
5 . The method according to claim 4 , wherein determining the reference distance comprises recording an actuation parameter for the coarse translation means associated to the required actuation distance.
6 . The method according to claim 5 , wherein the calibration routine further includes determining a second reference distance by recording a fine actuation distance required to bring the probe tip from the second, more proximal, reference separation to a working separation from the reference.
7 . The method according to claim 4 , wherein the calibration routine further includes determining a second reference distance by recording a fine actuation distance required to bring the probe tip from the second, more proximal, reference separation to a working separation from the reference.
8 . The method according to claim 1 , wherein the reference distance is defined relative to a fiducial provided to a stage for holding the substrate.
9 . The method according to claim 1 , further comprising a step of recording an optical height map including optical height records for individual ones of a plurality of target measurement areas along the substrate relative to a marker.
10 . The method according to claim 9 , wherein the marker is a fiducial provided to a stage for holding the substrate.
11 . The method according to claim 1 , wherein the SPM system comprises a plurality of individually addressable ones of the SPM head, each individually translatable by corresponding ones of the coarse and fine translation means, and wherein the landing procedure is applied to individual ones of the plurality of SPM heads.
12 . The method according to claim 1 , comprising an intermediate translation between the first and the second translation, said intermediate translation including an intermediate translation by the fine translation means without feedback control, wherein the intermediate translation is provided over a distance that corresponds to a fraction of the second reference distance.
13 . A non-transitory computer-readable medium comprising instructions, which when loaded into a memory of a scanning probe microscopy system, enable a controller of the system to carry out the method of claim 1 .
14 . A scanning probe microscopy (SPM) system comprising an SPM head for probing a substrate to be probed with a probe tip, a controller, and a translation means for adjusting a separation between the probe tip and the substrate,
the translation means communicatively connected to the controller, and including a course translation means for bringing the probe tip from an initial separation from the substrate to a more proximal separation, and a fine translation means for bringing the probe tip to a working separation,
wherein the SPM system is configured for performing a landing procedure including
applying a first translation over a first actuation distance by the coarse translation means to bring a probe tip held by an SPM head from an initial separation from a substrate to be probed to a second, more proximal, separation as defined by a characteristic transitional response of the probe tip in proximity to the substrate, and
applying a second translation, following the first translation, over a second actuation distance by the fine translation means under feedback control to bring the probe tip to a working separation, and
measuring an initial optical distance, indicative of the initial separation, using a detector, and relating the measured initial optical distance to a reference distance so as to determine a deviation;
wherein, the first actuation distance corresponds to a predetermined reference actuation distance associated to the reference distance and the deviation.
15 . The SPM system according to claim 14 , wherein the detector is an optical distance sensor provided to the SPM head configured for determining a focusing condition.
16 . The SPM system according to claim 15 wherein the SPM system comprises a fiducial provided to a stage for holding the substrate.
17 . The SPM system according to claim 14 wherein the SPM system comprises a fiducial provided to a stage for holding the substrate.
18 . The SPM system according to claim 14 , wherein the SPM system is further configured for performing a step of recording an optical height map including optical height records for individual ones of a plurality of target measurement areas along the substrate relative to a marker.
19 . The SPM system according to claim 18 , wherein the marker is a fiducial provided to a stage for holding the substrate.
20 . The SPM system according to claim 14 , comprising a plurality of individually addressable ones of the SPM head.