Apparatus for generating partially coherent radiation
The effective coherence of an undulator beamline can be tailored to projection lithography requirements by using a simple single moving element and a simple stationary low-cost spherical mirror. The invention is particularly suited for use in an illuminator device for an optical image processing system requiring partially coherent illumination. The illuminator includes: (i) source of coherent or partially coherent radiation which has an intrinsic coherence that is higher than the desired coherence; (ii) a reflective surface that receives incident radiation from said source; (iii) means for moving the reflective surface through a desired range of angles in two dimensions wherein the rate of the motion is fast relative to integration time of said image processing system; and (iv) a condenser optic that re-images the moving reflective surface to the entrance plane of said image processing system, thereby, making the illumination spot in said entrance plane essentially stationary.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC03-76SF00098
- Assignee:
- EUV LLC (Santa Clara, CA)
- Patent Number(s):
- 6,798,494
- Application Number:
- 09/944,391
- OSTI ID:
- 1175058
- Country of Publication:
- United States
- Language:
- English
Characterization of the accuracy of EUV phase-shifting point diffraction interferometry
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conference | June 1998 |
Modification of the coherence of undulator radiation
|
journal | February 1995 |
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Apparatus and method for generating partially coherent illumination for photolithography
Apparatus and method for generating partially coherent illumination for photolithography