Patent ID: 11922262
Assignee: CHANGXIN MEMORY TECHNOLOGIES, INC.
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 19:
20. The method for inspecting the photomask according to claim 14, wherein:
the plurality of sensor modules measuring the thickness of the photomask comprises:
measuring a distance between one of the plurality of the sensor modules and a robotic arm to obtain a first distance;
moving the photomask by the robotic arm so that the photomask passes through an irradiated area of the thickness measuring device for the photomask, wherein the plurality of sensor modules measures the distance between one of the plurality of sensor modules and a top surface of the photomask, to get a second distance; and
calculating a difference between the first distance and the second distance, wherein the difference is the thickness of the photomask.