Techniques for detecting probe landing in integrated circuit testing systems

One or more non-transitory machine-readable storage media storing instructions that, when executed by a machine, cause the machine to perform operations comprising:

• dithering a probe in a plane substantially parallel with a surface using a periodic motion having a dither frequency;
• directing a beam of charged particles toward a region of the probe;
• generating detector data describing the periodic motion of the probe based at least in part on an interaction between the beam of charged particles and the region of the probe;
• displacing the probe toward the surface;
• and detecting a contact between the probe and the surface using the detector data,
• wherein generating the detector data comprises generating filtered data using a lock-in amplifier tuned to the dither frequency, and wherein detecting the contact corresponds to an attenuation of an output of the lock-in amplifier at the dither frequency.

A system for testing integrated circuit components, the system comprising:

• a probe;
• a charged particle beam system;
• a detector, oriented toward the probe and configured to detect particles generated by interaction of charged particles and the probe;
• control circuitry, operably coupled to the probe, the charged particle beam system, and the detector, and configured to actuate the probe;
• and one or more non-transitory machine-readable storage media storing instructions that, when executed by the system, cause the system to perform operations comprising:
• dithering the probe in a plane substantially parallel with a surface using a periodic motion having a dither frequency at about a resonance frequency of the probe;
• directing a beam of the charged particles toward a region of the probe;
• generating detector data describing the periodic motion of the probe based at least in part on an interaction between the beam of charged particles and the region of the probe;
• displacing the probe toward the surface;
• and detecting a contact between the probe and the surface using the detector data,
• wherein generating the detector data comprises generating filtered data using a lock-in amplifier tuned to the dither frequency, and wherein detecting the contact corresponds to an attenuation of an output of the lock-in amplifier at the dither frequency.