Probe landing detection
AssigneeFEI Company
InventorYoav Neuman
Life of this patent
Estimating the term…
Abstract
Probe landing is detected by detecting a change in a vibration of the probe in a plane substantially parallel to the work piece surface as the probe is lowered toward the work piece. The vibration may be observed, for example, by acquiring multiple electron microscope images of the probe as it moves and analyzing the images the determine a characteristic, such as the amplitude of the vibration. When the probe contacts the work piece surface, the friction between the probe tip and the work piece surface will change the characteristic of the vibration, which can be detected to indicate that the probe has landed.
Claims19
A method for detection of contact of a probe with a work piece surface, comprising:
- moving the probe towards the work piece surface;
- vibrating the probe to induce periodic oscillations of the probe in a plane substantially parallel to the work piece surface;
- monitoring one or more vibration characteristics of the probe based on multiple images of at least a portion of the probe acquired by coordinating the acquisition of the multiple images with the periodic oscillations of the probe;
- and
- detecting a change, caused by contacting the work piece surface with the probe, in at least one of the vibration characteristics.
A method of detecting contact between a probe and a work piece surface, comprising:
- moving the probe in a direction having a first component normal to the work piece surface and having a second component parallel to the work piece surface, wherein the probe is oscillated periodically parallel to the work piece surface;
- monitoring the motion of the probe in the direction of the second component based on multiple images of at least a portion of the probe acquired by coordinating the acquisition of the multiple images with the periodic oscillations of the probe;
- detecting a change in the motion of the probe in the direction of the second component, caused by the probe contacting the work piece surface;
- and
- terminating the motion of the probe in a direction of the first component.
An apparatus for testing a circuit, comprising:
- a circuit probe assembly including a probe and at least one actuator configured to position the probe;
- a monitoring device configured to monitor the probe;
- a controller configured to control the monitoring device and to control the actuator to move the probe;
- and
- a computer memory storing computer instructions for controlling the monitoring device and the actuator for:
- moving the probe towards a work piece surface;
- vibrating the probe to induce periodic oscillations of the probe in a plane substantially parallel to the work piece surface;
- monitoring the vibration based on multiple images of at least a portion of the probe acquired by coordinating the acquisition of the multiple images with the periodic oscillations of the probe;
- and
- detecting a change in the vibration caused by the probe contacting the work piece surface.
Dependencies are inferred from the claim text.