Al has a good point - stylus profilometers are perfectly capable of
measuring step heights around 100nm.  Before you sputter, mask a small
sacrificial area of your wafer with a tiny piece of Kapton tape, sputter,
peel the tape off afterwards and measure the step height.  Just make sure
your tape is vacuum-compatible to avoid contaminating your chamber/film.

Brian C. Stahl
Graduate Student Researcher
UCSB Materials Research Laboratory
brian.stahl@gmail.com / bstahl@mrl.ucsb.edu
Cell: (805) 748-5839
Office: MRL 3117A


On Fri, Feb 13, 2009 at 9:13 AM, Albert Henning wrote:

> Neither ellipsometry nor reflectometry will be able to measure
> thicknesses of metal films in excess of about 50 nm.  Thicknesses beyond
> 50 nm cannot be distinguished optically from a bulk metal.  OTOH, even
> an ancient AlphaStep can work just fine.
>
> Al