Lighting system of a microlithographic projection exposure system and method for operating such a lighting system

Patent metadata

Field	Value
Publication number	US-2016349624-A1
Application number	US-201615236725-A
Country	US
Kind code	A1
Filing date	Aug 15, 2016
Priority date	Feb 19, 2014
Publication date	Dec 1, 2016
Grant date	—

Abstract

An illumination system of a microlithographic projection exposure apparatus includes a light source operated in a pulsed fashion and an array of optical elements which are digitally switchable between two switching positions. The array may be produced using MEMS technology.

First claim

What is claimed is:

1 . An illumination system, comprising:
an array of optical elements which are digitally switchable between two switching positions; and a control device configured to drive the optical elements so that during use of the illumination system the switching position of the optical elements: a) changes between two successive pulses of light generated by a light source; and b) is unchanged when the light source generates light pulses, wherein the illumination system is a microlithography illumination system.

2 . The illumination system of claim 1 , further comprising the light source configured to generate the pulses of light.

3 . The illumination system of claim 1 , wherein the control device is configured to drive the optical elements so that during use of the illumination system the switching position of at least one optical element is identical during two or more successive pulses of light generated by the light source.

4 . The illumination system of claim 3 , wherein:
the control device is configured to drive the optical elements so that during use of the optical system the switching position changes 2·n times between the two or more successive pulses of light generated by the light source; and n is an integer having a value of at least one.

5 . The illumination system of claim 1 , wherein the control device is configured to drive the optical elements so that during use of the illumination system:
the switching position of a first optical element is identical during a first number of successive pulses of light generated by the light source; the switching position of a first optical element is identical during a second number of successive pulses of light generated by the light source; the first number of successive pulses is greater than one; the second number of successive pulses is greater than one; and the first number is different from the second number.

6 . The illumination system of claim 5 , wherein the illumination system is configured to illuminate a mask during use of the illumination system.

7 . The illumination system of claim 6 , wherein the control device is configured to drive the optical elements so that during use of the optical system the switching position changes 2·n times between the two or more successive pulses of light generated by the light source, and n is an integer having a value of at least one.

8 . The illumination system of claim 5 , wherein the control device is configured to drive the optical elements so that during use of the optical system the switching position changes 2·n times between the two or more successive pulses of light generated by the light source, and n is an integer having a value of at least one.

9 . The illumination system of claim 1 , further comprising a lens in a path of the light pulses generated by the light source between the array and a target surface, wherein the lens is configured to image the array onto the target surface during use of the illumination system.

10 . The illumination system of claim 1 , wherein:
a first light source which is the light source configured to generate the pulses of light; the illumination system comprises a second light source configured to generate further pulses of light that are offset temporally with respect to the pulses of light generated by the first light source; in a first switching position of the optical elements, the array couples light pulses generated by the first light source into a common beam path of the illumination system; and in a second switching position of the optical elements, the array couples light pulses generated by the second light source into a common beam path of the illumination system.

11 . An apparatus, comprising:
an illumination system according to claim 1 ; and a projection lens, wherein the apparatus is a microlithographic projection exposure apparatus.

12 . A method of operating a microlithographic projection exposure apparatus comprising an illumination system and a projection lens, the method comprising:
using the illumination system to illuminate a pattern of a mask; and using the projection lens to image at least some of the illuminated pattern of the mask onto a light sensitive material, wherein the illumination system is an illumination system according to claim 1 .

13 . A method for operating an illumination system comprising an array of optical elements which are digitally switchable between two switching positions, the method comprising:
changing the switching position of the optical elements only between two successive pulses of light generated by a light source.

14 . The method of claim 13 , wherein the switching position of the optical elements is not changed during the pulses of light.

15 . The method of claim 13 , wherein the switching position of at least one of the optical elements is identical during two or more successive pulses of light.

16 . The method of claim 15 , wherein the number of light pulses during which the switching position is identical, during the illumination of a mask, is different for different optical elements.

17 . The method of claim 16 , wherein the switching position changes 2·n times between the two or more successive light pulses, and n is an integer having a value of at least one.

18 . The method of claim 15 , wherein the switching position changes 2 19 n times between the two or more successive light pulses, and n is an integer having a value of at least one.

19 . The method of claim 13 , wherein:
a first light source generates the pulses of light; a second light source generates further pulses of light that are offset temporally with respect to the pulses of light generated by the first light source; in a first switching position of the optical elements, the array couples light pulses generated by the first light source into a common beam path of the illumination system; and in a second switching position of the optical elements, the array couples light pulses generated by the second light source into a common beam path of the illumination system.

20 . The method of claim 13 , further comprising:
using the illumination system to illuminate a pattern of a mask; and using a projection lens to image at least some of the illuminated pattern of the mask onto a light sensitive material.

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Deguenther Markus
• Davydenko Vladimir
• Korb Thomas
• Eisenmenger Johannes

Classifications

• G03F7/70041 Primary

  by pulsed sources, e.g. multiplexing, pulse duration, interval control or intensity control · CPC title

• G03F7/70116

  Off-axis setting using a programmable means, e.g. liquid crystal display [LCD], digital micromirror device [DMD] or pupil facets · CPC title

• G03F7/7005

  by multiple sources, e.g. light-emitting diodes [LED] or light source arrays (addressable array sources specially adapted to produce patterns without a mask G03F7/70391) · CPC title

• G03F7/70058 Primary

  Mask illumination systems · CPC title

• G03F7/70075

  Homogenization of illumination intensity in the mask plane by using an integrator, e.g. fly's eye lens, facet mirror or glass rod, by using a diffusing optical element or by beam deflection · CPC title