Printability of quartz defects in a production Cr-less mask process

Chromeless PSM photomasks have been successfully applied to a production memory application. This 248-nm application has allowed an extremely aggressive, dense design to be successfully deployed without changing wavelength. This was achieved with an advanced resolution enhancement technique, a chromeless phase-shifting mask, to provide a more cost-effective total lithographic solution. The key to this technology is a mask that delivers high wafer-die yields, while delivering resolution at low k1. Therefore, the mask must have zero printing defects. In order to understand printing defects, many types of potential defects were analyzed and correlated back to the mask locations using both a 248-nm AIMs tool and SEM images. These defects were also correlated to a 257-nm KLA 576 tool using die-to-die inspection runs. This paper will examine chromeless mask phase-defect printing effects by using inspection capture at the key manufacturing steps (post-Cr etch, post-Qz Etch, and post-Cr removal). These defects will then be tracked through processes using SEM, AIMs, RAVE repair, and post-repair AIMs.