# US 10,768,531 B1 · System and method of maskless lithography with the use of a curvilinear hologram

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- Number: US 10,768,531 B1
- Document ID: US10768531B1
- Status: Granted
- Kind: B1
- Application number: 16/438,922
- Filed: 2019-06-12
- Granted: 2020-09-08
- Earliest claimed: 2019-06-12
- Applicants: Vadim Rakhovsky; Vitaly Chernik; Mikhail Borisov; Aleksey Shamaev; Dmitry Chelyubeev
- Inventors: Vadim Rakhovsky; Vitaly Chernik; Mikhail Borisov; Aleksey Shamaev; Dmitry Chelyubeev
- Web page: https://patentgrep.com/patent/US10768531B1

## CPC

- G03F 7/70291: {Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices}
- G03F 7/70408: {Interferometric lithography; Holographic lithography; Self-imaging lithography, e.g. utilizing the Talbot effect}
- G03F 7/703: {Non-planar pattern areas or non-planar masks, e.g. curved masks or substrates}
- G03H 1/0866: {Digital holographic imaging, i.e. synthesizing holobjects from holograms}
- G03H 1/0891: {Processes or apparatus adapted to convert digital holographic data into a hologram (G03H1/2294 takes precedence)}
- G03H 1/2286: {Particular reconstruction light (G03H1/24 takes precedence); Beam properties}
- G03H 1/2294: {Addressing the hologram to an active spatial light modulator}
- G03H 2001/0094: {for patterning or machining using the holobject as input light distribution}
- G03H 2222/52: Divergent beam
- G03H 2225/10: Shape or geometry
- G03H 2225/60: Multiple SLMs
- G03H 2240/61: SLM related parameters, e.g. pixel size
- G03H 2270/21: Curved bearing surface
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- G03H: HOLOGRAPHIC PROCESSES OR APPARATUS (holograms, e.g. point holograms, used as ordinary optical elements G02B5/32; producing stereoscopic or other three-dimensional effects G02B30/00; diffraction-grating systems G02B27/44; systems using moiré fringes G02B27/60; optical logic elements G02F3/00; stereo-photography G03B35/00; photosensitive materials or processes for photographic purposes G03C; {stereo-photographic or similar processes G03C9/00}; apparatus for processing exposed photographic materials G03D; analogue computers performing mathematical operations with the aid of optical elements G06E3/00; authentication by radiation, of concealed information carried by holograms or diffraction gratings G06K19/16; holographic storage G11B7/0065, G11C13/04; {stereoscopic or other three dimensional effects in television systems H04N13/00})

## Abstract

A system that contains a semi-ellipsoidal SLM holder supporting a plurality of flat rectangular SLMs, which are placed onto the semi-ellipsoidal surface of the holder in the most surface-covering way. The system contains a coherent light source placed in the first focal point of the ellipsoid. The second focal point of the ellipsoid defines the area in which an image-receiving object is to be placed. All the SLMs are illuminated by a diverging light beam emitted from the coherent light source. In each SLM, the light is subjected to phase-amplitude modulation and is converted into an image-carrying beam, which convergently fells onto the object on which the target image is to be produced. Thus, a pattern is formed on the object by a maskless method in which a plurality of SLMs are combined into a common image-forming holographic unit.

## Claims

### Claim 1

A system of maskless lithography for forming an image on an object with the use of a curvilinear hologram, the system comprising:
a spatial light modulator holder having a concave semi-ellipsoidal surface, a first focal point, and a second focal point;
a plurality of spatial light modulators covering the concave semi-ellipsoidal surface of the spatial light modulator holder, each spatial light modulator converting a light beam falling onto said spatial light modulator into a converging image-carrying beam reflected therefrom onto the object; and
a coherent light source that emits a diverging beam and is located in the first focal point for illuminating all spatial light modulators of said plurality with the diverging beam, the object being located in an area of the second focal point.

### Claim 2 (depends on 1)

The system of claim 1, wherein the coherent light source is a laser light source, the system further comprising a central processing unit.

### Claim 3 (depends on 2)

The system of claim 2, further comprising at least two micro-piezo actuators located between each spatial light modulator and the spatial light modulator holder for controlling a position of each spatial light modulator relative to the semi-ellipsoidal concave surface of the spatial light modulator holder, each micro-piezo actuator having an actuator driver and being connected to the central processing unit via said actuator driver.

### Claim 4 (depends on 3)

The system of claim 3, wherein each spatial light modulator having a spatial light modulator driver and being connected to the central processing unit via the spatial light modulator driver.

### Claim 5 (depends on 4)

The system of claim 4, further comprising an image processor, which is connected to the central processing unit for reproducing a reference image to adjust angular positions of the SLM via the micro-piezo actuators.

### Claim 6 (depends on 2)

The system of claim 2, wherein each spatial light modulator having a spatial light modulator driver and being connected to the central processing unit via the spatial light modulator driver.

### Claim 7 (depends on 2)

The system of claim 2, further comprising an image processor, which is connected to the central processing unit for reproducing a reference image to adjust angular positions of the SLM via the micro-piezo actuators.

### Claim 8

A method of maskless lithography with the use of a curvilinear hologram, the method comprising:
providing a system that contains a concave semi-ellipsoidal spatial light modulator holder having a concave semi-ellipsoidal surface that supports a plurality of flat rectangular spatial light modulators which cover the semi-ellipsoidal surface of the holder and are arranged in side-by-side positions, concave semi-ellipsoidal surface having a first focal point and a second focal point;
placing a coherent light source in the first focal point and an image-receiving object in the area of the second focal point;
illuminating all spatial light modulators with a diverging light beam emitted from the coherent light source;
subjecting the light received by each spatial light modulator to phase-amplitude modulation thus converting the illumination light into an image-carrying beam;
converging the image-carrying beam onto the object, thus producing a target image on the object.

### Claim 9 (depends on 8)

The method of claim 8, further comprising a step of improving a quality of image reproduction by: providing the system with a central processing unit, an image processor, and a reference image; reproducing the reference image on the object; and adjusting positions of the spatial light modulators relative to the concave semi-ellipsoidal surface while comparing the reference image reproduced by the image processor with an image reproduced by the spatial light modulators.