Silicon test specimens

This test specimen is made of a 5mm x 5mm square of single crystal silicon. It is photo-etched and the squares repeat every 10?m. The dividing lines are 1.9?m wide.

A broader etching line is written every 500?m, which is useful in light microscopy. This is an excellent test specimen for comparing magnification and assessing any distortion in the image field. It is ideally useful in the context of automated counting systems to check for unsuspected distortions. Where critical measurements must be made the sample can be mounted directly onto the calibration specimen so that an internal calibration is obtained on the micro-graph.