Novel Method to Address Wafer Surface Condition

Abstract

Minimal wafer loss is the goal of companies particularly in the cut throat semi-conductor industry. Unwanted moisture on the wafer surface at front end of the line can lead to defects in subsequent process steps. Typically, wafer surface exposed to moisture such as high humidity conditions can lead to wafer surface contamination. The moisture effect is addressed at a step which is after the initial processing steps thus minimizing the addition of any new steps affecting cycle time and cost of additional processing. Pre-clean, pad oxide and pad nitride are the typical initial steps of most of the technology nodes in semiconductor industry. Most of the work is done on wafer surface prior to introduction in the production line. This project focuses on addressing it at pad nitride step after the wafer is already processed in pre clean and pad oxide. Initially paper looks at the failure mode on incoming wafer surface, then methodology to eliminate or mitigate the incoming impact and finally optimize the step conditions for minimal impact.