发明名称 |
Tailored reflecting diffractor for EUV lithographic system aberration measurement |
摘要 |
A wavefront measurement system includes a source of electromagnetic radiation. An imaging system directs the electromagnetic radiation at an object plane that it uniformly illuminates. A first grating is positioned in the object plane to condition the radiation entering the input of a projection optic. A projection optical system projects an image of the first grating onto the focal plane. A second grating is positioned at the focal plane that receives a diffracted image of the source to form a shearing interferometer. A CCD detector receives the image of the first grating through the projection optical system and the second grating that forms a fringe pattern if there are aberrations in the projection optical system. Phaseshift readout of fringe pattern can be accomplished by stepping the first grating in a lateral direction and reading each frame with the CCD detector. The first grating includes a plurality of reflecting lines each formed by a plurality of reflecting dots. The first grating has a pitch that is ½ times the magnification of the projection system times the pitch of the second grating for achromatic operation.
|
申请公布号 |
US2004145714(A1) |
申请公布日期 |
2004.07.29 |
申请号 |
US20040753557 |
申请日期 |
2004.01.09 |
申请人 |
ASML HOLDING, N.V. |
发明人 |
POULTNEY SHERMAN K. |
分类号 |
G01J9/02;G02B5/18;G03F7/20;(IPC1-7):G03B27/52 |
主分类号 |
G01J9/02 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|