No abstract

This article presents a novel method to provide whole Deep Trench (DT) profile inspection. Bevel angle top-down polishing is used on pre-rotated substrates instead of traditional cross-section cleaving. This method can feedback the precise DT profile shape at specific depths to the production line for process tuning and troubleshooting.

A novel method has been developed to reveal the entire three dimensional (3D) deep trench (DT) capacitors for inspection in DRAM, especially NO capacitor dielectrics, ASG residues at corners, morphology etc., for process evaluation and failure analysis. It offers an alternative to conventional cross-section polishing, top down polishing or FIB milling methods. A DRAM chip was ground and polished down to a certain level from the chip backside. An etching solution was then applied to enhance the DTs appearance. 3D DTs can be inspected in scanning electron microscopy (SEM). The entire DTs or specific DT also can be lifted out for detailed investigation in transmission electron microscopy (TEM). The innovation of this technique is to provide a quick 3D observation in SEM, and much more flexibility to an entire DT inspection in TEM, which were not presented before.