Dark Field counting
We have an application where we are counting defects in a thin film coating. The setup is a dark field measurement with a 20x objective. We are looking for defects that are possibly down to 1um in diameter on a 100mm diameter sample. We have a macro that measures and NxN grid over the part. The trouble is in focusing. The program estimates focus at each location and adjusts the z-axis thru motor control. The trouble is focus may be slightly off and defects are missed or blurry resulting in errors in the data. Is there a method accurately controlling focus thru a script and motor control? We are using an version 7.0 of IPP on WIndows XP.