Endpoint Detection for Photolithography Mask Repair

摘要

A method includes scanning a lithography mask with a repair process, and measuring back-scattered electron signals of back-scattered electrons generated from the scanning. An endpoint is determined from the back-scattered electron signals. A stop point is calculated from the endpoint. The step of scanning is stopped when the calculated stop point is reached.

主权项

1. A method comprising:
scanning a lithography mask using an electron beam to repair the lithography mask, wherein the scanning is performed in an environment comprising a process gas, and wherein the process gas reacts with the lithography mask when stimulated by the electron beam; measuring back-scattered electron signals of back-scattered electrons generated from the scanning; determining an endpoint from the back-scattered electron signals; calculating a stop point from the endpoint; and stopping the step of scanning when the stop point is reached.