Next generation micro/nano metrology equipment

Lead Division
Metrology, Division 5

Other Divisions Participating
Polymer processing, Division 4
Metals, Division 7

Summary
Micro/Nano-metrology is facing big challenges that need to be addressed by the scientific community.

The 4M metrology division has performed an analysis of existing micro-measurement systems available in the partners´ laboratories. It found that no instrument manufacturer specifies the instrument response on high aspect ratio micro features, one of the most important aspects to verify in micro manufacturing. Many other challenges are also related to the dimensional measurement of micro features (see e.g. L. Mattsson, “Metrology of micro-components – a real challenge for the future”, in the Proceedings of the 5th International Seminar on Intelligent Computation in Manufacturing Engineering (CIRP ISME ’06), 25 – 28 July 2006, Ischia, Italy pp 547 - 552)

Thanks to the development of 3D-structured metal moulds produced by X-ray LIGA techniques in the Polymer and Metal divisions, the possibility of testing the response of optical surface profilers and coordinate measuring machines has been possible. In addition to this, this Cross Divisional project will analyze the measurement routines and results by round robin tests of simpler 3D-micro structures.

Figures (a) and (b) on the right demonstrate the difficulties optical microscope based measuring systems face when being used for characterizing deep and narrow micro-features in surfaces. They are optical microscope images of X-ray LIGA manufactured 3D-structures in nickel, having height variations of almost 200 micrometer.

In figure [a] the focus is on the bright Ni top surface. The dark areas should be 190 micrometer deep “canals” with widths ranging from 75 micrometer (left horizontal bar) to 5 micrometer.

In figure [b] we focus at the bottom of the “canals” we get a very poor image, and we can just barely discriminate some details from the central part of the 75 micrometer wide “canal.” The narrower ones can not be analyzed using this optical microscope.

This is the problem that image analyzing software in optical profiling instruments faces when applied to deep micro-features. In the best case the software will say No – when no obvious image can be formed from the bottom surface. In the worst case it will just report erroneous results. This cross divisional project will therefore determine the measurable aspect ratio limits for different types of instrument. It will also be the platform for evaluating the next generation of metrology equipment aimed at providing more precise 3D-micro metrology.

Instrument manufacturers and others interested in analyzing and verifying their instrument performance of deep and narrow micro-features are welcome to contact project leader Lars Mattsson

Status of this cross-divisional project
The final report is available to 'Partners Only' in the filestore.