Pattern generator mirror configurations

• US 6,987,599 B2
• Filed: 05/30/2003
• Issued: 01/17/2006
• Est. Priority Date: 03/02/1998
• Status: Expired due to Term

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: Micronic Laser Systems AB (Mycronic AB)
• Inventors: Sandstrom, Torbjorn
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Choi, William
• Application Number:
  US10/449,661
• Publication Number:
  US 20030202233A1
• Time in Patent Office: 963 Days
• Field of Search: 359/223, 359/225, 359/290, 359/291, 359/295, 359/298, 359/281, 359/285, 359/318, 359/392, 345/84, 345/85, 355/67, 355/53, 250/491.1, 250/492.1, 250/492.2, 250/396.R, 348/771, 348/760, 430/311, 430394-396, 430/5, 430/22, 430/30
• US Class Current: 359/290
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/064 by means of optical elements, e.g. lenses, mirrors or prisms
• CPC Class Codes: B23K 26/0648 comprising lenses
• CPC Class Codes: B41J 2/465 using masks, e.g. light-switching masks
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 27/0043 in projection exposure systems, e.g. microlithographic systems
• CPC Class Codes: G02B 27/4205 having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
• CPC Class Codes: G03F 7/2022 Multi-step exposure, e.g. hybrid; backside exposure; blanket exposure, e.g. for image reversal; edge exposure, e.g. for edge bead removal; corrective exposure
• CPC Class Codes: G03F 7/70041 by pulsed sources, e.g. multiplexing, pulse duration, interval control or intensity control
• CPC Class Codes: G03F 7/70283 Mask effects on the imaging process
• CPC Class Codes: G03F 7/70291 Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices
• CPC Class Codes: G03F 7/704 Scanned exposure beam, e.g. raster-, rotary- and vector scanning mask projection exposure involving relative movement of patterned beam and workpiece during imaging G03F7/70358
• CPC Class Codes: G03F 7/70475 Stitching, i.e. connecting image fields to produce a device field, the field occupied by a device such as a memory chip, processor chip, CCD, flat panel display
• CPC Class Codes: G03F 7/70725 control
• CPC Class Codes: G09G 3/2007 Display of intermediate tones
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833
• CPC Class Codes: H04N 1/195 the array comprising a two-dimensional array or a combination of two-dimensional arrays
• CPC Class Codes: H04N 2201/0414 Scanning an image in a series of overlapping zones
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]

Abstract

The present invention relates to an apparatus for creating a pattern on a workpiece sensitive to radiation, such as a photomask a display panel or a microoptical device. The apparatus comprises a source for emitting electromagnetic radiation, a spatial modulator having multitude of modulating elements (pixels), adapted to being illuminated by said radiation, and a projection system creating an image of the modulator on the workpiece. It further comprises an electronic data processing and delivery system receiving a digital description of the pattern to be written, extracting from it a sequence of partial patterns, converting said partial patterns to modulator signals, and feeding said signals to the modulator, a precision mechanical system for moving said workpiece and/or projection system relative to each other and an electronic control system coordinating the movement of the workpiece, the feeding of the signals to the modulator and the intensity of the radiation, so that said pattern is stitched together from the partial images created by the sequence of partial patterns. According to the invention the drive signals can set a modulating element to a number of states larger than two.

Claims

1. A method of spatial intensity light modulation for use in optical projection systems including:

providing a regular grid of separately addressable mirror elements, said mirror element having a pivot action, wherein mirror elements in the grid are arranged so that a first mirror element has an adjacent second mirror element with a substantially different pivot action;

actuating the mirror elements to form a pattern; and

projecting radiation from the mirror elements onto an image plane to reproduce the pattern;

wherein the radiation originates from a single illumination source.

2. The method of claim 1, wherein said grid is a Cartesian grid.

3. The method of claim 1, wherein the grid has rows of pixels and the mirror elements in a row pivot in the same direction, and where mirror elements in adjacent rows pivot in opposite directions.

4. The method of claim 1, wherein the mirror grid is formed on top of an integrated circuit.

5. A method of spatial intensity light modulation for use in optical projection systems including:

providing a regular grid of separately addressable mirror elements, said mirror element having a pivot action, wherein mirror elements in the grid are arranged so that a first mirror element has an adjacent second mirror element with a substantially different pivot action;

actuating the mirror elements to form a pattern;

projecting radiation from the mirror elements onto an image plane to reproduce the pattern; and

wherein the grid is composed of identical groups of four pixels, where each group has pixels pivoting in four different directions, and the vector sum over the directions in each group is zero.

6. A method of spatial intensity light modulation for use in optical projection systems including:

providing a regular grid of separately addressable mirror elements, said mirror element having a pivot action, wherein mirror elements in the grid are arranged so that a first mirror element has an adjacent second mirror element with a substantially different pivot action;

actuating the mirror elements to form a pattern;

projecting radiation from the mirror elements onto an image plane to reproduce the pattern; and

wherein the grid is composed of identical groups of mirror elements, wherein a group has mirror elements with four different pivot actions, and a vector sum of direction vectors for equally actuated mirror elements of the group is essentially zero.

7. A spatial intensity light modulator for use in an optical projection system that projects radiation from mirror elements onto an image plane to reproduce a pattern, including:

a regular grid of separately addressable mirror elements, said mirror element having a pivot action, wherein mirror elements in the grid are arranged so that a first mirror element has an adjacent second mirror element with a substantially different pivot action; and

a single radiation source, optically coupled to project radiation onto the mirror elements.

8. The device of claim 7, wherein said grid is a Cartesian grid.

9. A spatial intensity light modulator for use in an optical projection system that projects radiation from mirror elements onto an image plane to reproduce a pattern, including:

a regular grid of separately addressable mirror elements, said mirror element having a pivot action, wherein mirror elements in the grid are arranged so that a first mirror element has an adjacent second mirror element with a substantially different pivot action; and

wherein the grid is composed of identical groups of four pixels, where each group has pixels pivoting in four different directions, and the vectors sum over the directions in each group is zero.

10. A spatial intensity light modulator for use in an optical projection system that projects radiation from mirror elements onto an image plane to reproduce a pattern, including:

a regular grid of separately addressable mirror elements, said mirror element having a pivot action, wherein mirror elements in the grid are arranged so that a first mirror element has an adjacent second mirror element with a substantially different pivot action; and

wherein the grid is composed of identical groups of mirror elements, wherein a group has mirror elements with four different pivot actions, and a vector sum of direction vectors for equally actuated mirror elements of the group is essentially zero.

11. A method of spatial intensity light modulation for use in optical projection systems comprising the steps of:

providing a regular grid of separately addressable mirror elements, said mirror element having a pivot action, wherein mirror elements in the grid are arranged so that a vector sum of direction vectors for a group of equally actuated adjacent mirror elements is essentially zero;

actuating the mirror elements to form a pattern; and

projecting radiation from the mirror elements onto an image plane to reproduce the pattern.

12. The method of claim 11, wherein said grid is a Cartesian grid.

13. The method of claim 11, wherein the mirror elements are deformed by application of an analog voltage.

14. The method of claim 11, wherein said group has the size two by two pixels.

15. The method of claim 11, wherein the grid has rows of pixels and the mirror elements in a row pivot in the same direction, and where mirror elements in adjacent rows pivot in opposite directions.

16. The method of claim 11, wherein the grid is composed of identical groups of four pixels, where each group has pixels tilting in four different directions, and the vector sum over the directions in each group is zero.

17. The method of claim 11, wherein the grid is composed of identical groups of four pixels, where each group has pixels pivoting in four different directions, and the vector sum over the directions in each group is zero.

18. The method of claim 11, wherein the mirror grid is formed on top of an integrated circuit.

19. The method of claim 11, wherein said group includes three nearest neighbor mirror elements.

20. A spatial intensity light modulator for use in an optical projection system that projects radiation from mirror elements onto an image plane to reproduce a pattern, including:

a regular grid of separately addressable mirror elements, said mirror element having a pivot action, wherein mirror elements in the grid are arranged so that a vector sum of direction vectors for a group of equally actuated adjacent mirror elements is essentially zero.

21. A method of spatial intensity light modulation for use in optical projection systems including:

providing a regular grid of separately addressable mirror elements, said mirror element having a pivot action, wherein mirror elements in the grid are arranged so that;

a first mirror element has an adjacent second mirror element with a substantially different pivot action; and

a vector sum of direction vectors for a group of equally actuated adjacent mirror elements is essentially zero;

actuating the mirror elements to form a pattern; and

projecting radiation from the mirror elements onto an image plane to reproduce the pattern.

22. The method of claim 21, wherein said grid is a Cartesian grid.

23. The method of claim 21, wherein the mirror elements are deformed by application of an analog voltage.

24. The method of claim 21, wherein said group has the size two by two pixels.

25. The method of claim 21, wherein the grid has rows of pixels and the mirror elements in a row pivot in the same direction, and where mirror elements in adjacent rows pivot in opposite directions.

26. The method of claim 21, wherein the grid is composed of identical groups of four pixels, where each group has pixels tilting in four different directions, and the vector sum over the directions in each group is zero.

27. The method of claim 21, wherein the grid is composed of identical groups of four pixels, where each group has pixels pivoting in four different directions, and the vector sum over the directions in each group is zero.

28. The method of claim 21, wherein the mirror grid is formed on top of an integrated circuit.

29. The method of claim 21, wherein said group includes three nearest neighbor mirror elements.

30. A spatial intensity light modulator for use in an optical projection system that projects radiation from mirror elements onto an image plane to reproduce a pattern, including:

regular grid of separately addressable mirror elements, said mirror element having a pivot action, wherein mirror elements in the grid are arranged so that;

a first mirror element has an adjacent second mirror element with a substantially different pivot action; and

a vector sum of direction vectors for a group of equally actuated adjacent mirror elements is essentially zero.