| Popis: |
The paper provides new insights into Silicon wafer measurements in context of technological problems of developing a sophisticated measurement technique, which harnesses helium atom beam as a probe. Nano-resolution imaging techniques such as scanning tunnelling microscopy (STM) and atomic force microscopy (AFM) are well-know in surface science. A scanning helium atom microscope, where a focused beam of low energy, neutral helium atoms is used as an imaging probe is a new concept creating non-destructive and non-invasive surface investigation tool in science and industry. This paper is focused on measurements of flatness and thickness of the wafer, which is used as a deflecting mirror of the helium beam. Two -optics based- measurement techniques are presented: scanning confocal system and the Fizeau interferometer. The latter is applied as a quick reference device placed close to the production line whereas the former offers high accuracy flatness and thickness maps of the wafers. |
