Pattern generator

• US 7,009,753 B2
• Filed: 02/12/2004
• Issued: 03/07/2006
• 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 C
• Application Number:
  US10/776,192
• Publication Number:
  US 20040165170A1
• Time in Patent Office: 754 Days
• Field of Search: 359/223, 359/290, 359/291, 359/295, 359/298, 250/396.R, 250/491.1, 250/492.2, 430/5, 430/22, 430/30, 430/311, 430394-396, 355/52, 355/53, 355/55, 355/67, 355/69, 355/401, 355/402
• US Class Current: 359/291
• 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 may include a source for emitting light flashes, a spatial modulator having modulating elements (pixels), adapted to being illuminated by the radiation, and a projection system creating an image of the modulator on the workpiece. It may further include an electronic data processing and delivery system receiving a digital description of the pattern to be written, converting the pattern to modulator signals, and feeding the signals to the modulator. An electronic control system may be provided to control a trigger signal to compensate for flash-to-flash time jitter in the light source.

Claims

1. An apparatus for creating a pattern on a workpiece sensitive to light radiation, comprising:

a light source for emitting light flashes in the wavelength range from EUV to IR,

a spatial light modulator (SLM) having a multitude of modulating elements (pixels), adapted to be illuminated by said radiation,

a projection system creating an image of the modulator on the workpiece,

an electronic data processing and delivery system receiving a digital description of the pattern to be written, converting said pattern to modulator signals, and feeding said signals to the modulator,

a precision mechanical system for positioning said workpiece and/or projection system relative to each other, and

an electronic control system controlling the position of the workpiece, the feeding of the signals to the modulator and the intensity of the radiation, so that said pattern is printed on the workpiece,

wherein said electronic control system is further arranged to control a trigger signal to the light source for emitting the light flashes so that a trigger signal timing is varied to compensate for flash-to-flash time jitter in said light source, and at least partially correct for pattern placement errors.

2. The apparatus of claim 1, wherein the electronic control system is arranged to control a time offset of the trigger signal.

3. The apparatus of claim 2, wherein the offset value is estimated based on a measured delay between a trigger signal and a resulting exposure for at least one of the latest exposures.

4. The apparatus of claim 1, whereby the light source is a laser.

5. The apparatus of claim 1, where the pattern is formed in photoresist, photopolymer or photographic emulsion.

6. A method for creating a pattern on a workpiece sensitive to light radiation, comprising:

emitting light flashes in the wavelength range from EUV to IR,

modulating the emitted light with a spatial light modulator (SLM) having a multitude of modulating elements (pixels),

projecting an image of the modulator on the workpiece, and

controlling the emitted radiation, the modulator and the positioning of the workpiece in relation to the projected image, based on a digital description of the pattern to be written, so that said pattern is printed on the workpiece,

wherein controlling the emitted radiation involves controlling a trigger signal for emitting the light flashes so that a trigger signal timing is varied to compensate for flash-to-flash time jitter, and at least partially correct for pattern placement errors.

7. The method of claim 6, wherein a time offset of the trigger signal is controlled.

8. The method of claim 7, wherein the offset value is estimated based on a measured delay between a trigger signal and a resulting exposure for at least one of the latest exposures.

9. An apparatus for creating a pattern on a workpiece sensitive to light radiation, comprising:

a light source for emitting light flashes in the wavelength range from EUV to IR,

a spatial light modulator (SLM) having a multitude of individually controllable modulating elements (pixels), adapted to be illuminated by said radiation,

a projection system for creating an image of the modulator on the workpiece, and

an electronic control system controlling the position of the image created on the workpiece, the modulation elements of the modulator and the intensity of the radiation, in accordance with an intended pattern to be printed,

wherein said electronic control system is further arranged to control a trigger signal to the light source for emitting the light flashes so that a trigger signal timing is varied to compensate for flash-to-flash time jitter in said light source, and at least partially correct for pattern placement errors.

10. The apparatus of claim 9, wherein the electronic control system is arranged to control a time offset of the trigger signal.

11. The apparatus of claim 10, wherein the offset value is estimated based on a measured delay between a trigger signal and a resulting exposure for at least one of the latest exposures.

12. The apparatus of claim 9, whereby the light source is a laser.

13. The apparatus of claim 9, where the pattern is formed in photoresist, photopolymer or photographic emulsion.

14. An apparatus for creating a pattern on a photosensitive workpiece, comprising:

a light source for emitting light flashes in the wavelength range from EUV to IR,

a projection system for directing the emitted light to the workpiece, and

a control system arranged to control a trigger signal to the light source for emitting the light flashes,

wherein a trigger signal timing is varied to compensate for flash-to-flash time jitter in said light source, and at least partially correct for pattern placement errors.

15. The apparatus of claim 14, wherein the electronic control system is arranged to control a time offset of the trigger signal.

16. The apparatus of claim 15, wherein the offset value is estimated based on a measured delay between a trigger signal and a resulting exposure for at least one of the latest exposures.

17. A method for creating a pattern on a workpiece sensitive to light radiation, comprising:

emitting light flashes in the wavelength range from EUV to IR,

projecting the emitted light on the workpiece, and

controlling a trigger signal for emitting the light flashes so that a trigger signal timing is varied to compensate for flash-to-flash time jitter, and at least partially correct for pattern placement errors.

18. The method of claim 17, wherein a time offset of the trigger signal is controlled.

19. The method of claim 18, wherein the offset value is estimated based on a measured delay between a trigger signal and a resulting exposure for at least one of the latest exposures.

20. An apparatus for creating a pattern on a photosensitive workpiece, comprising:

a light source for emitting light flashes in the wavelength range from EUV to IR,

a projection system for directing the emitted light to the workpiece, and

a control system arranged to control a trigger signal to the light source for emitting the light flashes,

wherein, during scanning, the control system measures a delay between a previous trigger signal and a resulting exposure to determine a timing of a subsequent trigger signal, and at least partially correct for pattern placement errors.

21. The apparatus of claim 20, wherein the electronic control system is arranged to control a time offset of the subsequent trigger signal.

22. A method for creating a pattern on a workpiece sensitive to light radiation, comprising:

emitting light flashes in the wavelength range from EUV to IR,

projecting the emitted light on the workpiece, and

during scanning, measuring a delay between a previous trigger signal and a resulting exposure to determine a timing for a subsequent trigger signal, and at least partially correct for pattern placement errors.

23. The method of claim 22, wherein a time offset of the subsequent trigger signal is controlled.