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| Author(s): |
José Cândido de Souza Filho
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Escola Politécnica (EP/BC) |
| Defense date: | 2008-07-01 |
| Examining board members: |
Sebastião Gomes dos Santos Filho;
Lucila Helena Deliesposte Cescato;
Newton Cesario Frateschi;
Oswaldo Horikawa;
Mikiya Muramatsu
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| Advisor: | Sebastião Gomes dos Santos Filho |
| Abstract | |
In this work, it is proposed an alternative geometry to detect LASER light scattering to obtain the average size and concentration of particles adhered on silicon wafers with different surface finishing. It was used a theoretical model for light scattering from dieletric particles which were previously deposited onto polished surfaces. This model is based on the analitical scattering theory of suspended particles developed by Gustav Mie26 which was adapted for particles adhered on silicon surfaces28,29. To characterize our Home-Built Equipment, it was used different samples with different surface features: silicon wafers with LATEX spheres of four different diameters (0.1 mm, 0.6 mm, 1.1 mm and 5.0 mm), surface lines with different width, height and inter-spacing, and liquid micro-drops of glicerine with several diameters (500-1800 mm). We have obtained the total intensity of scattered light as a function of the scattering section for each mentioned feature. Also, particle counting and, in some cases, measurements of horizontal assimetry of the particles were done. The light scattering measurements of particles and micro-drops were modeled using the Unbstructed Reflection Model to obtain the scattering sections with the aid of a calculation routine as proposed by Bohren and Huffman. (AU) | |