Reduction of shorts between polysilicon word lines on a 4 Meg DRAM product

A significant reduction in defects in a polysilicon level was achieved by a team of process and diagnostic engineers. This paper will describe the methodology. Electrical measurements on a defect test site were used together with surface particle counter data and automated optical inspection to understand the problems and determine the success of various actions. Improvements were made at the oxidation, polysilicon deposition, anneal, photolithography, and RIE operations.