Multiple directional scans of test structures on srmiconductor integrated circuits

A method of inspecting a sample, comprising:

• a. in a first direction, scanning a first portion of the sample with an incident charged particle beam and detecting a portion of charged particles emitted from the sample in response to the incident charged particle beam;
• b. determining a general location of a defect based on the detected charged particles from the first direction scan, wherein the general location corresponds to a second portion of the sample which is outside the first direction scan;
• c. in a second direction, scanning the second portion of the sample with an incident charged particle beam and detecting a portion of charged particles emitted from the sample in response to the incident charged particle beam, the second direction being at an angle to the first direction;
• and
• d. determining a specific location of a defect based on the detected charged particles from the second direction scan, wherein the specific location corresponds to a third portion of the sample which is contained within the second portion of the sample.