Contact Hole Process Printability Beyond 180nm On Binary Mask

This work discusses the extension of conventional method using binary masks in enhancing contact hole resolution. This can be achieved by selection of masks, mask design including choice of optical proximity correction (OPC), exposure tool, illuminator design, and resist design to do imaging process integration. The main goal is to avoid the use of PSM masks. The possible use of the binary mask prior to switching to PSM for smaller contact hole size had been evaluated by using the latest improved photoresist. A few process parameters were evaluated to achieve this objective.