Optical metrology: From the laboratory to the real world

Abstract

Optical metrology has shown to be a versatile tool for the solution of many inspection problems. The main advantages of optical methods are the noncontact nature, the non-destructive and fieldwise working principle, the fast response, high sensitivity, resolution and accuracy. Consequently, optical principles are increasingly being considered in all steps of the evolution of modern products. However, the step out of the laboratory into the harsh environment of the factory floor was and is a big challenge for optical metrology. The advantages mentioned above must be paid often with strict requirements concerning the measurement conditions and the object under test. For instance, the request for interferometric precision in general needs an environment where high stability is guaranteed. If this cannot be satisfied to a great extent special measures have to be taken or compromises have to be accepted. But the rapid technological development of the components that are used for creating modern optical measurement systems, the unrestrained growth of the computing power and the implementation of new measurement and inspection strategies give cause for optimism and show that the high potential of optical metrology is far from being fully utilized. In this article current challenges to optical metrology are discussed and new technical improvements that help to overcome existing restrictions are treated. On example of selected applications the progress in bringing optical metrology to the real world is shown.