Collector for EUV light source

Abstract

The invention discloses a method and a device for removing the fragments from a reflective surface of an EUV collector for an EUV light source. The reflective surface includes a first material; the fragment includes a second material and / or a compound of the second material. The system and the method include a controlled sputtering ion source which comprises a gas including sputtering ion source atoms; and an exciting mechanism for exciting the atoms of the sputtering ion material to an ionized state. The ionized state is selected to a sputtering probability which is distributed around a selected energy peak, has a high sputtering probability to the second material and an extremely low probability to the first material. The exciting machenism includes an RF or microwave induction mechanism. The gas is retained partially according to the pressure of the selected energy peak. The exciting mechanism generates an ion inflow quantity. An atom sputtering density of the second material formed on the surface of a reflector is equal to or over the inflow rate of second material plasma fragment atoms. A sputtering rate is selected with respect to the expected life of the assigned reflective surface. The reflective surface is covered. The light collector includes an elliptical mirror and a fragment screen including a radially extending groove. The first material is molybdenum, the second material is lithium and the ion material is helium. The system has a heater for evaporating the second material from the reflective surface. The exciting mechanism is linked to the reflective surface among the ignition period and the reflective surface has a barrier layer.

Description

[0001] This application is a divisional application of the application with the international application number PCT / US2004 / 010972, the international application date is April 7, 2004, the Chinese national application number is 200480009342.4, and the application title is "light collector for EUV light source". field of invention [0002] This invention relates to the field of generating EUV (soft X-ray) light for applications such as lithographic exposure sources for semiconductor integrated circuits, and in particular to light collectors for such devices. [0003] related application [0004] This application is a continuation-in-part of US Serial No. 10 / 409,254, filed April 8, 2003, the contents of which are incorporated herein by reference. Background of the invention [0005] Applications such as semiconductor integrated circuit fabrication with increasingly smaller critical dimensions require a shift from generation of extreme ultraviolet (DUV) light to generation of e...

AI Technical Summary

Problems solved by technology

Braun also discusses the theoretical practicality of applying Mo / Si / Ag or Mo / Si / Ru triple layers, which theoretically have higher reflectivity, but due to the voids in the Ag layer at the desired thickness and the Mo / Si / Ru The Si / C / Ru multilayer stack has a calculated optimal reflectivity of λ = 13.5nm, its thickness is constrained in the Mo layer to prevent crystallization in the Mo layer, so the Ag example cannot achieve the theoretical reflectivity

However, Braun also found that the Mo / Si / C / Ru multilayer stack did not meet the theoretically calculated reflectivity expectations, perhaps because the surface roughness of the initial deposition of the Mo layer was distributed upward through the stack.

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