公开(公告)号：US20190017816A1

公开(公告)日：2019-01-17

申请号：US16061471

申请日：2016-11-28

Applicant: ASML NETHERLANDS B.V.

Inventor： Antonius Johannes Maria NELLISSEN ,  Jacob Roger HAARTSEN ,  Krassimir Todorov KRASTEV

IPC: G01B13/22 ,  G03F7/20

Abstract: A height measurement apparatus comprising an array of differential pressure sensors, each differential pressure sensor comprising a reference outlet and a measurement outlet, the reference outlet being a predetermined distance from a reference surface, and each differential pressure sensor further comprising an inlet configured to provide pressurized gas for the reference outlet and the measurement outlet. A flexible membrane is positioned such that a reference side of the flexible membrane is in fluid communication with the reference outlet and a measurement side of the flexible membrane is in fluid communication with the measurement outlet. The flexible membrane is configured to move when a pressure change occurs at the measurement outlet and a detector is configured to monitor the movement of the flexible membrane.