Method for validating measurement data

A method comprising:

• with a computer connected to a measurement tool, receiving a design data having design feature, wherein a material feature is formed on a substrate according to the design feature;
• with the measurement tool, performing a measurement on the material feature by applying an electron beam on the material feature and collecting a secondary electron signal from the material feature using a scanning electron microscope (SEM) tool;
• with the computer, executing a simulation using the design feature to generate a simulated secondary electron signal;
• and
• in response to determining that a difference between the collected secondary electron signal and the simulated secondary electron signal exceeds a predetermined value, re-measuring the material feature with the measurement tool.

A system comprising:

• a design database;
• a measurement tool connected to the design database, the measurement tool configured to:
• with a source, generate a source signal on a material feature;
• and
• with a detector, collect a response signal from the material feature to obtain a measurement of the material feature;
• and
• a computer connected to the measurement tool and the design database, wherein the computer is configured to:
• generate a simulated response signal;
• and
• cause the measurement tool to re-measure the material feature in response to determining that a difference between the response signal and the simulated response signal exceeds a predetermined value.