Mask repair using layout-based pattern copy for the 65 nm node and beyond

To overcome several drawbacks of the standard pattern copy procedure used to create the repair shape(s) for a particular defect site, we have developed and implemented a layout based pattern copy method (a.k.a. "database pattern copy"). In general, pattern copy derives the repair structure by comparing a high resolution image of the defective area with the same image of a non-defective area. The repair shape is generated as the difference of these two images, and adjusted for processing purposes. As opposed to the conventional pattern copy method, which derives the reference using information taken from the mask under repair, the new method uses reference information from the original mask design file. As a result, it reduces the CD error of the repair, simplifies the repair process work flow, and greatly reduces the potential of operator error. We present the new method along with experimental results taken from programmed defect repair on our MeRiT MG (TM) production tool.