Patent ID: 11959961
Assignee: ORBOTECH LTD.
Field: Measurement (Instruments)
Classification: CPC G  B | IPC B  G

Claim 12:
13. A method comprising:
moving a modulator in a first direction, the modulator being configured to detect defects in electrical circuits;
emitting, by a laser source positioned adjacent to a first side of the modulator, laser light toward a second side of the modulator in a direction parallel to the surface of the modulator and at a first angle relative to the first direction, and the laser light partially overlaps the surface of the modulator;
redirecting, by at least one mirror positioned adjacent to the second side of the modulator opposite the first side, the laser light toward the first side of the modulator at a second angle relative to the first direction;
detecting, by a laser sensor positioned adjacent to the first side of the modulator, a first change in intensity in the laser light received from the laser source when a particle on the surface of the modulator passes through the laser light emitted by the laser source;
detecting, by the laser sensor, a second change in intensity in the laser light received from the laser source redirected by the at least one mirror when the particle on the surface of the modulator passes through the laser light redirected by the at least one mirror; and
determining, by a processor, an X-Y location of the particle based on the first change in intensity and the second change in intensity.