Future application of e-beam repair tool beyond 3X generation

Currently, repair technology is one of the key factors in mask making process regarding TAT reduction and yield level enhancement. Since its commercial release EB repair tool has been commonly used for production line and contributed to high quality repair. But it is not guaranteed whether those conventional machines can keep up with future pattern reduction trend or not. In 2Xnm generation node some advanced exposure techniques seem to be adopted and that will inevitably require higher specification of repair machine. A simple lithography simulation predicts 5nm of indispensable repair accuracy for 2Xnm generation pattern. This number implies the necessity of upper class machine. Generally, the error budget of EB repair tool is composed of three to four components, stated another way mechanical stability, electrical (charging) uniformity, process stability, and graphical quality including software ability. If errors from those components are reduced, overall repair accuracy could be better. A suggestion which can improve those errors was issued last year from tool vender including new machine concept. We have conducted several kind of experiment in order to confirm the performance of new machine. In this paper, we will report the result of experiment and consider which part can effectively contribute to repair accuracy. And we have also evaluated its practical utility value for 2Xnm node by verifying actual application of some 3Xnm production masks.