Title: A precise inspection technique for wafer pre-sawing lines using Affine transformation

Authors: Hyung Tae Kim, Kang Won Lee, Sung-Chul Kim, Hae-Jeong Yang

Addresses: Mechatronics Team, Korea Institute of Industrial Technology, Cheonan, Chungnam, South Korea. ' Mechatronics Team, Korea Institute of Industrial Technology, Cheonan, Chungnam, South Korea. ' AM Technology, Ansan, Kyunggi, South Korea. ' Department of Machine Design, Siheung, Kyunggi, South Korea

Abstract: This study proposes a simple and fast technique for detecting wafer cutting lines using the Affine transformation before sawing. This technique was developed for the purpose of wafer alignment when alignment marks are unavailable. The edges of the pre-sawing lines are complex and there are bright shapes in the sawing lines, so it is difficult to apply the conventional edge finding method. The sawing lines are represented by rectangular windows which are deformed by an Affine transformation. The amount of deformation is determined when the grey level in the window is a global minimum in the image. The global minimum is found by the golden section search. The algorithm was tested using 13 sample images and repeated ten times for each image. The results showed that the processing time was below 1200 ms and the deviation was in the sub-pixel level. We found that the proposed method can be applied to align wafers in the dicing process.

Keywords: wafer dicing; sawing lines; affine transformation; dynamic ROI; wafer cutting lines; wafer alignment; deformation; precise inspection.

DOI: 10.1504/IJCAT.2010.034729

International Journal of Computer Applications in Technology, 2010 Vol.39 No.1/2/3, pp.46 - 52

Published online: 18 Aug 2010 *

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