Optical system for a microlithographic projection exposure apparatus and microlithographic exposure method

Patent metadata

Field	Value
Publication number	US-9442385-B2
Application number	US-201414297375-A
Country	US
Kind code	B2
Filing date	Jun 5, 2014
Priority date	Jan 12, 2012
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

The invention relates to an optical system for a microlithographic projection exposure apparatus, and to a microlithographic exposure method. An optical system for a microlithographic projection exposure apparatus comprises a polarization-influencing optical arrangement, wherein the polarization-influencing optical arrangement comprises at least one first array of first polarization-influencing elements and a second array of second polarization-influencing elements, wherein the first and second arrays are arranged successively in the light propogation direction, wherein the first and second polarization-influencing elements in each case have a birefringence that is dependent on the presence of an electric field, and wherein the first polarization-influencing elements and the second polarization-influencing elements are transverse Pockels cells.

First claim

The invention claimed is:

1. An optical system, comprising:
a polarization influencing optical arrangement, comprising:
a first array comprising first transverse Pockels cells;
a second array comprising second transverse Pockels cells; and
a plurality of electrodes configured to generate an electric field, wherein:
the first and second arrays are arranged successively in a direction that light propagates through the system during use of the system;
the first transverse Pockels cells have an electric-field dependent birefringence;
the second transverse Pockels cells have an electric-field dependent birefringence;
the electrodes are in each case arranged on mutually opposite sides of the first transverse Pockels cells and of the second transverse Pockels cells;
the electrodes arranged on the first array are oriented at a non-zero angle relative to the electrodes arranged on the second array; and
the optical system is a microlithographic optical system.

2. The optical system of claim 1 , wherein the electrodes are configured as a plurality of electrode pairs, wherein each transverse Pockels cell has at least two corresponding electrode pairs assigned to different pairs of mutually opposite sides of the cell.

3. The optical system of claim 2 , wherein the electrode pairs are configured so that, for each electrode pair, an electrical voltage is applicable to the electrode independently of a different electrode pair.

4. The optical system of claim 1 , wherein fast axes of the birefringence inducible in the first transverse Pockels cells are oriented at a non-zero angle with respect to fast axes of the birefringence that are induceable in the second transverse Pockels cells.

5. The optical system of claim 4 , wherein the angle is 45°±5°.

6. The optical system of claim 1 , wherein the first transverse Pockels cells are in a hexagonal arrangement.

7. The optical system of claim 6 , wherein the second transverse Pockels cells are in a hexagonal arrangement.

8. The optical system of claim 1 , wherein the polarization-influencing optical arrangement is arranged in a pupil plane of the optical system.

9. The optical system of claim 1 , wherein, for each of a multiplicity of channels running through the arrangement, the polarization influencing optical arrangement is configured to produce different polarization rotation angles for linearly polarized light passing through a respective channel, in a manner dependent on whether or not a predefined electrical voltage is present at the transverse Pockels cell situated in the region of the respective channel.

10. The optical system of claim 9 , wherein the polarization rotation angles are in each case an integral multiple of 45°.

11. The optical system of claim 1 , wherein the optical system is configured so that during use of the system, by selectively applying a predefined electrical voltage to the transverse Pockels cells, a constantly linear polarization distribution of light passing through the optical system is converted into a quasi-tangential or quasi-radial polarization distribution.

12. The optical system of claim 1 , further comprising a diffractive optical element.

13. The optical system of claim 1 , further comprising a third array comprising third transverse Pockels cells.

14. The optical system of claim 1 , wherein the optical system is a microlithographic illumination device.

15. The optical system of claim 1 , wherein the electrodes are configured as a plurality of pairs of electrodes, each pair of electrodes being arranged on opposite sides of a corresponding Pockels cell so that, during use of the optical system, the electrode pair generates an electric field across the corresponding Pockels cell.

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

17. A method of using a microlithographic projection exposure apparatus comprising an illumination device and a projection lens, the method comprising:
using the illumination device to illuminate an object in an object field; and
using the projection lens to project an image of the object into an image field,
wherein the illumination device comprises an optical system according to claim 1 .

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Saenger Ingo
• Schlesener Frank

Classifications

• G03F7/70191 Primary

  Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like · CPC title

• G03F7/70566

  Polarisation control · CPC title

• G03F7/70108 Primary

  Off-axis setting using a light-guiding element, e.g. diffractive optical elements [DOEs] or light guides · CPC title