Inspection apparatus and method

A non-transitory computer-readable medium having instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to at least:

• obtain multiple images of a pattern generated by receipt by a level sensor of an inspection system of a plurality of beamlets that reflect off a substrate, wherein each image is formed by a different beamlet and supports measurement of a deviation value of the substrate from a different target height;
• and
• determine a first deviation value of the substrate from a first target height based on a first image of the images that supports measurement of the deviation value of the substrate from the first target height and a second deviation value of the substrate from a second target height different from the first target height based on a second image of the images that supports measurement of the deviation value of the substrate from the second target height.

An inspection apparatus comprising:

• multiple radiation reflecting components, wherein each radiation reflecting component is associated with one beamlet of a plurality of beamlets, is configured to provide a respective beamlet on a the substrate, and is configured to support a different target height for a substrate by enabling detection of a height or a levelness of the substrate based on the associated beamlet reflecting off the substrate;
• and
• a non-transitory computer-readable medium having instructions therein, the instructions, when executed by one or more processors, configured to cause the one or more processors to at least determine a first height or first deviation value from a target height using a first radiation reflecting component of the multiple radiation reflecting components but not a second radiation reflecting component of the multiple radiation reflecting components and determine a second height or second deviation value from a target height using the second radiation reflecting component of the multiple radiation reflecting components but not the first radiation reflecting component of the multiple radiation reflecting components.