Optical image forming method and device, image forming apparatus and aligner for lithography

• US 6,288,830 B1
• Filed: 05/12/1999
• Issued: 09/11/2001
• Est. Priority Date: 05/13/1998
• Status: Expired due to Fees

• Current Assignee: Ricoh Microelectronics Co. Ltd. (Ricoh Company Limited)
• Original Assignee: Ricoh Microelectronics Co. Ltd. (Ricoh Company Limited)
• Inventors: Kinoshita, Makoto
• Primary Examiner(s): Lester, Evelyn A
• Application Number:
  US09/310,131
• Time in Patent Office: 853 Days
• Field of Search: 359/202, 359/212, 359/223, 359/224, 359/260-292, 359/295, 359/298, 359/205, 359/846, 359/849, 359/850, 359/867, 355/67
• US Class Current: 359/292
• CPC Class Codes: B41J 2/465 using masks, e.g. light-switching masks
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• 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

Abstract

An optical image forming method and device, an image forming apparatus, and an aligner for lithography, capable of forming a light image at a high pixel density and enhancing the intensity of irradiated light to each pixel by effectively utilizing reflected light from respective mirrors of a spatial light modulator. The optical image forming device has a light source, a DMD including a plurality of mirrors, each capable of independently controlling the inclination of a reflecting surface thereof for reflecting light from the light source, wherein reflected light from the DMD is irradiated to an object moving in one direction relative to the reflected light to form a light image on the object. The respective mirrors of the DMD are arranged such that reflected light images therefrom are aligned on the object in a direction orthogonal to the direction of the relative movement, with a pitch smaller than the pitch p of the mirrors. A controller controls the inclination of the reflecting surface of each of the mirrors. A microlens including a plurality of lenses converges reflected light from corresponding mirrors of the DMD onto the object.

Claims

1. An optical image forming method for forming a light image on an object, comprising the steps of:

irradiating light from a light source to a spatial light modulator including a plurality of mirrors arranged in an array of mirror rows and mirror columns, with a pitch p for the mirror columns, each of said mirrors capable of independently controlling the inclination of a reflecting surface thereof;

irradiating reflected light from said spatial light modulator to an object which moves in a first direction relative to said reflected light;

arranging said respective mirrors of said spatial light modulator to reflect light therefrom; and

converging said reflected light from plural of said respective mirrors in one column of said spatial light modulator onto one pixel of said object such that reflected light images from said mirrors of said spatial light modulator are aligned on said object in a second direction orthogonal to the first direction of the relative movement of said object with a pitch smaller than the pitch p of said mirrors.

2. An optical image forming device for forming a light image on an object, said device comprising:

a light source;

a spatial light modulator including a plurality of mirrors arranged in an array of mirror rows and mirror columns, with a pitch p for the mirror columns, each of said mirrors capable of independently controlling the inclination of a reflecting surface thereof for reflecting light modulator is irradiated to an object which moves in a first direction relative to said reflected light;

a controller which controls the inclination of the reflecting surface of each of said mirrors; and

a plurality of lenses each for converging reflected light from a corresponding mirror plural of said mirrors in one column of said spatial light modulator onto one pixel of said object such that reflected light images from said mirrors of said spatial light modulator are aligned on said object in a second direction orthogonal to the first direction of the relative movement of said object with a pitch smaller than the pitch p of said mirrors.

3. An optical image forming device according to claim 2, wherein:

said spatial light modulator includes n mirror rows arranged in the direction of the relative movement, each of said mirror rows including m mirrors arranged with the pitch p in the direction orthogonal to the direction of the relative movement, said mirror rows being arranged with an offset in the direction orthogonal to the direction of the relative movement; and

said controller controls the inclination of the reflecting surface of each of said mirrors, such that reflected light images from said respective mirrors are aligned in the direction orthogonal to the direction of the relative movement.

4. An optical image forming device according to claim 2, wherein:

said spatial light modulator includes n mirror rows arranged in the direction orthogonal to a longitudinal direction of said spatial light modulator, each of said mirror rows including m mirrors arranged with the pitch p in the longitudinal direction, to form an array of (n×

m) mirrors which constitute said spatial light modulator;

the longitudinal direction of said spatial light modulator is inclined with respect to the direction orthogonal to the direction of the relative movement, so as to sequentially shift the position at which a reflected light image reflected off an i^th mirror, wherein i varies 1 to m, in each of said mirror rows is formed in the direction orthogonal to the direction of the relative movement; and

said controller controls the inclination of the reflecting surface of each of said mirrors such that reflected light images from said respective mirrors are aligned in the direction orthogonal to the direction of the relative movement.

5. An image forming apparatus, comprising:

a latent image forming mechanism which irradiates a light image to a uniformly charged image carrier to form a latent image;

a developing mechanism which develops the latent image on said image carrier to form an actual image; and

a transfer mechanism which transfers the actual image on said image carrier onto a transfer material,

an optical image forming device which comprises a light source;

a spatial light modulator including a plurality of mirrors arranged in an array of mirror rows and mirror columns, with a pitch p for the mirror columns, each of said mirrors capable of independently controlling the inclination of a reflecting surface thereof for reflecting light from said light source, wherein reflected light from said spatial light modulator is irradiated to an object which moves in a first direction relative to said reflected light;

a controller which controls the inclination of the reflecting surface of each of said mirrors; and

a plurality of lenses each for converging reflected light from a corresponding plural of said mirrors in one column of said spatial light modulator onto one pixel of said object such that reflected light images from said mirrors of said spatial light modulator are aligned on said object in a second direction orthogonal to the first direction of the relative movement of said object with a pitch smaller than the pitch p of said mirrors.

6. An aligner for lithography for irradiating a light image to a substrate having a photoresist layer formed on a surface thereof, said aligner comprising an optical image forming device which comprises:

a light source;

a spatial light modulator including a plurality of mirrors arranged in an array of mirror rows and mirror columns, with a pitch p for the mirror columns, each of said mirrors capable of independently controlling the inclination of a reflecting surface thereof for reflecting light from said light source, wherein reflected light from said spatial light modulator is irradiated to an object which moves in a first direction relative to said reflected light;

a controller which controls the inclination of the reflecting surface of each of said mirrors; and

a plurality of lenses each for converging reflected light from a corresponding plural of said mirrors in one column of said spatial light modulator onto one pixel of said object such that reflected light images from said mirrors of said spatial light modulator are aligned on said object in a second direction orthogonal to the first direction of the relative movement of said object with a pitch smaller than the pitch p of said mirrors.