公开(公告)号：US20240355579A1

公开(公告)日：2024-10-24

申请号：US18138709

申请日：2023-04-24

Applicant: KLA Corporation

Inventor： Yeishin Tung ,  Peter Lin ,  Mi Zhang ,  Chengping Zhang ,  Sameet Shriyan

IPC: H01J37/22 ,  G01B11/14 ,  H01J37/20

CPC classification number: H01J37/226 ,  G01B11/14 ,  H01J37/20

Abstract: A beam of light is directed at a workpiece on a stage. The workpiece is disposed an absolute distance from an electron beam column. The beam of light that is reflected off the workpiece is received at a sensor. Using the beam of light, a nominal distance between the electron beam column and the workpiece on the stage is determined.