Method and device for generating optical radiation by means of electrically operated pulsed discharges

US9414476B2 · kind B2 · utility

Assignees

• Fraunhofer-Gesellschaft zur förderung der angewandten Forschung e.V. · DE
• Ushio Denki Kabushiki Kaisha · JP

Inventors

• Ralf Pruemmer · Geilenkirchen, DE
• Ralf Conrads · Aachen, DE
• Klaus Bergmann · Heilbronn, DE
• Felix Kuepper · Viersen, DE
• Jeroen Jonkers · Seevetal, DE

Key dates

• Filing date: Jun 12, 2012
• Grant date: Aug 9, 2016
• Expiry date: Jan 16, 2033

Classification

• Technology area (CPC H): Electricity
• CPC primary: H05G2/0088
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

The present invention relates to a method and device for generating optical radiation (18), in particular EUV radiation or soft x-rays, by means of electrically operated discharges. A plasma (15) is ignited in a gaseous medium between at least two electrodes (1, 2), wherein said gaseous medium is produced at least partly from a liquid material (6), which is applied to one or several surface(s) moving in the discharge space and is at least partially evaporated by one or several pulsed energy beam(s) (9). At least two consecutive pulses (16) are applied within a time interval of each electrical discharge onto said surface(s). The delay between and/or the pulse energy of said consecutive pulses is controlled to stabilize the position of an emission center of the plasma (15).