Methods and apparatus for use with extreme ultraviolet light having contamination protection
| DWPI Title: Contamination protection apparatus for extreme UV (EUV) actinic mask inspection system, has low pressure gas source fluidly coupled to intermediate opening of duct whose lower and upper end openings are maintained at lower pressure |
| Abstract: An apparatus for use with extreme ultraviolet (EUV) light comprising A) a duct having a first end opening, a second end opening and an intermediate opening intermediate the first end opening the second end opening, B) an optical component disposed to receive EUV light from the second end opening or to send light through the second end opening, and C) a source of low pressure gas at a first pressure to flow through the duct, the gas having a high transmission of EUV light, fluidly coupled to the intermediate opening. In addition to or rather than gas flow the apparatus may have A) a low pressure gas with a heat control unit thermally coupled to at least one of the duct and the optical component and/or B) a voltage device to generate voltage between a first portion and a second portion of the duet with a grounded insulative portion therebetween. |
| Use: Contamination protection apparatus for thermophoretic protection and reducing contaminants in extreme UV (EUV) system such as EUV actinic mask inspection system or EUV lithographic system (claimed). |
| Advantage: A larger optical component area is protected from contamination by maintaining a suitable length to width ratio for each duct in the array. Performance of system is enhanced by reducing or eliminating contaminants that are commonly encountered during use of system. The contaminants are reduced in amount or prevented from landing on optical surfaces or other operational surfaces of the systems by sweeping the contaminants from the duct or sweeping the contaminants before entry into the duct. |
| Novelty: The apparatus (100) has a duct (110) comprising an intermediate opening (116) between lower and upper end openings (112,114). An optical component (120) e.g. lens receives EUV light from lower end opening after light passes through upper end opening or sends light to upper end opening through lower end opening. A low pressure gas source (130) providing molecular hydrogen/helium gas at 0.1 atmospheric pressure or less and having high transmission of EUV light, is fluidly coupled to intermediate opening. The two end openings are maintained at pressure lower than 0.1 atmospheric pressure. |
| Filed: 2/10/2014 |
| Application Number: US14176587A |
| Tech ID: SD 12581.1 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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