White Light Interferometry a production worthy technique for measuring surface roughness on semiconductor wafers

 

Roy T. Blunt

 

IQE (Europe) Ltd., Cypress Drive, St. Mellons, Cardiff, CF3 0EG, UK.

e-mail: rblunt@iqep.com Tel:+44 (0) 2920 839400

 

Keywords: Surface roughness, White light interferometry, Coherence correlation interferometry

 


Abstract

Reproducible, quantitative, and rapid surface roughness measurements would be valuable in many aspects of semiconductor and optical technology e.g. routine assessment of polished substrates and of epitaxial layers. However, such measurements are rarely made probably because most measurement techniques available have serious disadvantages in a production environment. In this work we have used white light interferometry to measure a range of semiconductor surfaces. This technique offers many advantages in terms of measurement speed, ease of use, reproducibility and freedom from damage or contamination. The fundamentals of the technique are described and results obtained on a wide range of semiconductor surfaces discussed. Results are shown to be comparable to those obtained by AFM and to show excellent long term reproducibility and stability.

 

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