Prospects and challenges for the optical inspection of micro- and nano- structures

Abstract

Optical technologies are faced with a bunch of challenges. In this paper, several approaches are discussed which can be helpful to meet these requirements. To them belong robust and single shot technologies, model-based and resolution enhanced approaches, in-line and remote technologies. Optical metrology has shown to be a versatile tool for the solution of many measurement and inspection tasks. The main advantages of optical methods are the non-contact nature, the non-destructive and areal working principle, the fast response, flexible scalability, high sensitivity, resolution and accuracy. Consequently, optical principles are increasingly being considered in many areas where reliable data about the shape, the surface properties, the stress state and the strength of the object under test have to be measured. However, these advantages must be paid with some serious disadvantages that are mainly connected with the unpleasant properties of identification problems and the high sensitivity of optical methods against environmental influences. Several examples are presented where optical metrology can be helpful for the inspection of micro and nano components. The presentation is focused on two topics:

- the discussion of the potential and the limitations of optical inspection technologies and the resulting challenges, and

- the discussion of modern inspection technologies that refer to these challenges.

The given examples relate to both the inspection of MEMS as well semiconductor nanostructures.