J. L. Lue, A. Huang, T. Wang, ProMOS Technologies Inc., Hsinchu, Taiwan

Summary: A novel approach has been developed for determining planar profiles of Deep Trench (DT) Capacitors at any particular depths using mechanical polishing instead of FIB milling method for process monitoring, development, and failure analysis. The sample is polished at a small beveled angle and then is inspected in SEM. This method not only provides a quick way for the inspection of DT planar profiles at any depths in detail but also inspects the DTs in a much larger area than has ever been seen before;the variation in the overall DT profile can be examined within one beveled surface. In addition, this technique is simple to use and it is very cost effective because the FIB is not needed.