System for correcting aberrations and distortions in EUV lithography
US6897940B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 4, 2003 |
| Grant date | May 24, 2005 |
| Priority date | — |
| Expiry date | Jun 4, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24802
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A system for correcting aberration and distortion in EUV lithography places a reticle on a deformable reticle chuck, and a reticle height sensor is used to measure the surface height of the reticle placed on the deformable reticle chuck. An optical system projects EUV radiation onto the reticle and collects and projects reflected EUV radiation from the reticle through its exit pupil onto a wafer placed on a wafer chuck. A deformable mirror disposed proximal to the exit pupil may also be controlled for this purpose. The deformable reticle chuck and the deformable mirror are controlled such that aberration and distortion of an image of the reticle formed on the wafer by the optical system are corrected based on the height measured by the reticle height sensor. The deformable reticle chuck includes a supporting structure, a deformable membrane disposed above and being comprised of a dielectric layer and a conductive layer, a voltage source connected to the conductive coating on the reticle and the conductive layer to generate an electrostatic attractive force between them, a plurality of actuator rods each connected to a corresponding one of actuators, and a coolant gas inside a chamb…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.