Pattern Recognition Software

Rudolph Technologies, a provider of film thickness metrology systems, offers the Zheng pattern recognition software for its SpectraLASER, MetaPULSE and FOCUS FE VII tools. The software cuts the time it takes to recognize alignment patterns while providing significantly more robust pattern recognition, especially on low-contrast CMP and etch wafers. The new pattern recognition software has been successfully installed at several customer sites and is transparent to users. Currently, no differences are seen in creating and running recipes. However, improvements in the ease of training, searching a pattern, and in throughput will be seen.

Improved robustness stems from improved data processing algorithms that enable greater immunity to both color and contrast variations. On some wafers, color and contrast vary from site to site, making it difficult for some pattern recognition systems to reliably recognize the pattern. To overcome this problem, many systems use edge mode pattern recognition, avoiding the color variation altogether. On the most difficult wafers, even this approach can fail when the color change produces large image contrast changes compared with the image where the pattern was trained. Rudolph Technologies's proprietary pattern recognition algorithm uses both color and edge detection as well as advanced noise cancellation algorithms to handle color and contrast variations, giving fewer failures on the most difficult wafers.

<%=company%>, One Rudolph Rd., Flanders, NJ 07836. Tel: 973-691-1300. Fax: 973-691-5480.