EUVL mask repair: expanding options with nanomachining

Evaluation of multilayer defect repair viability and protection techniques for extreme ultraviolet masks

“…Figure 1 shows repair and treatment processes for sample creation. In order to follow the way of improving wafer print quality, 13 an electron beam (EB) repair tool was used to widen the absorber pattern at first and then a nanomachining repair tool was used to excavate various amounts of multilayer. The dimension of absorber repair defined as D is targeted 60 nm in lateral direction.…”

“…The dimension of multilayer repair, defined as Z is from 35 to 70 nm in depth, follows previous work. 13 After applying the repair process to the pattern, three kinds of protective layer treatments were performed in order to protect the exposed multilayer from degradation due to cleans.…”

“…Micromachining was introduced to address multilayer defects and attempts to correct for the phase effect by judicious removal of multilayer material. [13][14][15] Despite promising results from prior studies, considerations for HVM and lifetime durability of micromachined repair sites have remained largely unexplored. In particular, exposed multilayer sidewalls have been shown to significantly degrade after several mask cleans.…”