| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a level sensor which is used to measure the height of a substrate in a lithographic projection device, can be also used for a single-stage immersion lithographic device, has no process dependency, is of high reaction rate, and is of a kind different from a conventional type. <P>SOLUTION: The level sensor includes a transmitter 10 and a receiver 11. The transmitter is configured to transmit a pressure wave 100 to a predetermined position on the surface of a substrate between the substrate W and a projection system PS, and to allow the substrate W to reflect at least a part of the pressure wave. The receiver receives at least a part of the reflected wave. The level sensor is configured to determine the height of the surface in the substrate W based on the pressure wave transmitted and received. The level sensor can be used for immersion process, quickly works and has a scarce process dependency, because the pressure wave is used. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
