Pattern generator using EUV

• US 6,687,041 B1
• Filed: 08/31/2000
• Issued: 02/03/2004
• Est. Priority Date: 03/02/1998
• Status: Expired due to Term

• Current Assignee: ASML Netherlands BV (ASML Holding NV), Robert Bosch GmbH
• Original Assignee: Micronic Laser Systems AB (Mycronic AB)
• Inventors: Sandstrom, Torbjorn
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): TRA, TUYEN Q
• Application Number:
  US09/623,270
• Time in Patent Office: 1,251 Days
• Field of Search: 359/290, 359/291, 359/295, 359/298, 359/223, 250/492.1, 250/492.2, 250/491.1, 250/396.R, 430/5, 430/394, 430/395, 430/396, 355/67, 355/53
• 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 with extremely high resolution on a workpiece, such as a pattern on a semiconductor chip. The apparatus comprises a source for emitting electromagnetic radiation in the EUV wavelength range, a spatial modulator (SLM) having a multitude of pixels, 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, and a precision mechanical system for moving said workpiece and/or projection system relative to each other. It further comprises 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.

Claims

1. An apparatus for creating a pattern with extremely high resolution on a workpiece, such as a pattern on a semiconductor chip with 50 nm wide lines, comprising:

a source for emitting electromagnetic radiation in the EUV wavelength range,

a spatial modulator having a multitude of modulating elements (pixels), adapted to being 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, extracting from the digital description 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.

2. An apparatus according to claim 1 where the spatial light modulator is reflective.

3. An apparatus according to claim 1 where the spatial light modulator has multivalued pixels.

4. An apparatus according to claim 1, where an optical path is built with reflecting optics.

5. An apparatus according to claim 1 further comprising a imaging lens, wherein the imaging lens has a ring-shaped field and the spatial light modulator has a ring-shaped aperture.

6. An apparatus according to claim 1, where an optical path is evacuated.

7. An apparatus according to claim 1 where the spatial light modulator works by diffraction.

8. An apparatus according to claim 1, where the spatial light modulator is a solid plate of piezoelectric material with a reflecting front surface which deforms in response to electric addressing voltages, thereby creating a wavefront modulation.

9. An apparatus according to claim 8, where the spatial light modulator is connected to an active semiconductor chip.

10. An apparatus according to claim 1, where the radiation has an oblique angle at the spatial light modulator.