CPL mask technology for sub-100-nm contact hole imaging

Contact patterning for the 65nm device generation will be an exceedingly difficult task. The 2001 SIA roadmap lists the targeted contact size as 90nm with +/-10% CD control requirements of +/- 9nm1. Defectivity levels must also be below one failure per billion contacts for acceptable device yield. Difficulties in contact patterning are driven by the low depth of focus of isolated contacts and/or the high mask error factor (MEF) for dense contact arrays (in combination with expected reticle CD errors). Traditional contact lithography methods are not able to mitigate both these difficulties simultaneously. Inlaid metal trench patterning for the 65nm generation has similar lithographic difficulties though not to the extreme degree as contacts. We have investigated the use of CPL mask technology for ArF contact hole imaging for sub-100nm contact imaging. The author's activities have been focused on the design, fabrication and integration of imaging technology. In this paper the author's emphasis will be on issues related to pattern layout, mask fabrication and image processing.