Whole field curvature and residual stress determination of silicon wafers by reflectometry
Ng, Chi Seng
Asundi, Anand Krishna
Date of Issue2011
Proceedings of SPIE - Instrumentation, Metrology, and Standards for Nanomanufacturing, Optics, and Semiconductors V
School of Mechanical and Aerospace Engineering
Reflectometry, a simple whole-field curvature measurement system using a novel computer aided phase shift reflection grating method has been improved to certain extend. The similar system was developed from our earlier works on Computer Aided MoirÃ© Methods and Novel Techniques in Reflection MoirÃ©, Experimental Mechanics (1994) in which novel structured light approach was shown for surface slope and curvature measurement. This method uses similar technology but coupled with a novel phase shift system to accurately measure surface profile, slope and curvature. In our previous paper, "Stress Measurement of thin wafer using Reflection Grating Method", the surface curvature and residual stresses were evaluated using the versatility of the proposed system.. The curvature of wafers due to the deposition of backside metallization was evaluated and compared with a commercially stress measurement system from KLA-Tencor. In this paper, some aspects of the work are extended. Our proposed system is calibrated using a reference flat mirror and spherical mirror certified by Zygo Corporation. The mirrors together with the camera calibration toolbox allow the system to acquire measurement accuracy that is demanded by semiconductor industry. Finally, the results obtained from Reflectometry are compared and contrast with results from KLA Tencor System.
© 2011 Society of Photo-optical Instrumentation Engineers (SPIE). This paper was published in Proceedings of SPIE - Instrumentation, Metrology, and Standards for Nanomanufacturing, Optics, and Semiconductors V and is made available as an electronic reprint (preprint) with permission of Society of Photo-optical Instrumentation Engineers (SPIE). The published version is available at: [http://dx.doi.org/10.1117/12.894396]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.