Thomas L. Warner’s scientific contributions

... measured at many scattering angles, 0 * for each detector and a graph plotted that shows the angular distribution o f scatter Analysis o f this graph can give an indication o f surface texture parameters[57] ARS and TIS have been used to detect surface defects on silicon wafers m the semiconductor industry[77][78][79][80] and for inspecting computer disks[81] In conjunctionwith high-speed laser scanning, they provide a quick non-contact form o f inspection for contamination and other defects at an early stage o f semiconductor manufacture, thus improving fabrication yield TIS is generally used for bare silicon wafers and ARS for patterned wafers Defects in these applications consist o f contamination, scratches, pits and polishing defects Hard disk substrates require a certain amount o f roughness as controlled textunng promotes adhesion o f the magnetic layer that stores data In these applications light scattered due to the surface roughness o f the sample is considered background noise Work in this area has focused on reducing the minimum size for defect detection 3 3 3 On-line and Fibre-Optic Methods o f Surface Roughness Measurement Much work has been done in the field o f measuring surface roughness through measurement o f light scattenng Most o f this applies to measuring the roughness o f highly smooth surfaces such as optical parts using ARS and TIS, and has been m the field o f bulk optics The bulk optic configurations o f ARS and TIS are mainly unsuitable for on-line use using fibre-optics ...

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Laser-based fibre-optic sensor for measurement of surface properties