Method of manufacturing spatial light modulator and electronic device employing it
First Claim
1. A method of fabricating a spatial light modulator, comprising the steps of:
- (a) forming a conductive silicon mirror substrate having;
a plurality of micromirrors arranged in one of a line and matrix;
at least one torsion bar coupling said micromirrors in one direction;
and reflective layers formed at least on one surface of said micromirrors;
(b) forming an electrode substrate having;
a depression in a central region;
a rim around the periphery thereof;
sets of electrodes having conducting layers disposed within said depression in positions corresponding to said micromirrors, and driving said micromirrors in an inclining manner by means of a coulomb force; and
pillars projecting from said depression in positions corresponding to an interval between two of said micromirrors adjacent in said one direction; and
(c) positioning at least intermediate portions of said at least one torsion bar on said silicon mirror substrate opposite to said pillars of said electrode substrate, and bonding said silicon mirror substrate to said electrode substrate.
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Abstract
A spatial light modulator is constructed from a conductive silicon mirror substrate and a glass electrode substrate including sodium, anode-bonded together. The silicon mirror substrate has micromirrors arranged in a matrix, torsion bars coupling these micromirrors in the x-direction, and a frame coupled to both ends of the torsion bars. A glass electrode substrate has a central depression, a rim around the periphery thereof, pillars projecting from within the depression, and electrodes and wiring driving micromirrors formed within the depression in an inclining manner. Both ends of the torsion bars are bonded to the rim of the frame portion, and intermediate portions of the torsion bars are bonded to the pillars. Both ends of the torsion bars are cut away from the frame portion during dicing.
24 Citations
42 Claims
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1. A method of fabricating a spatial light modulator, comprising the steps of:
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(a) forming a conductive silicon mirror substrate having;
a plurality of micromirrors arranged in one of a line and matrix;
at least one torsion bar coupling said micromirrors in one direction;
and reflective layers formed at least on one surface of said micromirrors;
(b) forming an electrode substrate having;
a depression in a central region;
a rim around the periphery thereof;
sets of electrodes having conducting layers disposed within said depression in positions corresponding to said micromirrors, and driving said micromirrors in an inclining manner by means of a coulomb force; and
pillars projecting from said depression in positions corresponding to an interval between two of said micromirrors adjacent in said one direction; and
(c) positioning at least intermediate portions of said at least one torsion bar on said silicon mirror substrate opposite to said pillars of said electrode substrate, and bonding said silicon mirror substrate to said electrode substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of fabricating a spatial light modulator having a plurality of micromirrors arranged in one of a line and matrix comprising the steps of:
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(a) forming an electrode substrate having;
a depression in a central region;
a rim around the periphery thereof;
a sets of electrodes having conducting layers disposed within said depression in positions corresponding to said micromirrors, and driving said micromirrors in an inclining manner by means of a coulomb force; and
pillars projecting from said depression in positions corresponding to an interval between two of said micromirrors adjacent in said one direction;
(b) bonding a silicon substrate having a doped layer doped with impurities on one surface thereof to said electrode substrate so that at least said pillars of said electrode substrate are opposite to said doped layer;
(c) etching and removing said silicon substrate so that leaving said doped layer is left;
(d) forming a reflective layer on a surface of said doped layer; and
(e) etching said doped layer and said reflective layer to form a silicon mirror substrate from said doped layer and reflective layer, said etching step having the steps of;
forming said plurality of micromirrors in positions opposite said sets of electrodes, and forming at least one torsion bar coupled with said micromirrors in said one direction, said at least one torsion bar being bonded to said pillars at positions between two of said micromirrors adjacent in said one direction and to one of said rim and pillers at both ends. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A spatial light modulator having a conductive silicon mirror substrate doped with impurities and an electrode substrate are bonded integrally wherein said silicon mirror substrate, comprises:
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a plurality of micromirrors arranged in one of a line and matrix and having reflective layers formed on one surface; and
a torsion bar coupling said micromirrors in one direction;
at least one said electrode substrate comprises;
a depression in a central region thereof;
a rim around the periphery thereof;
sets of electrodes formed within said depression in positions corresponding to said micromirrors and driving said micromirrors in an inclining manner by means of a coulomb force; and
pillars projecting from said depression in positions corresponding to an interval between two of said micromirrors adjacent in said one direction; and
whereinat least intermediate portions of said at least one torsion bar on said silicon mirror substrate are opposite said pillars of said electrode substrate, and said silicon mirror substrate and said electrode substrate are bonded. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A spatial light modulator, comprising:
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a glass substrate on which at least one conductive torsion bar coupling a plurality of conductive micromirrors in one direction is supported by pillars, and on which a conductive frame portion fixing both ends of said at least one torsion bar is formed; and
a circuit substrate on which a plurality of pairs of electrodes opposite each of said micromirrors and a circuit element energizing said plurality of pairs of electrodes are formed;
and wherein said frame portion of said glass substrate and said circuit substrate are bonded. - View Dependent Claims (33, 34, 35)
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36. A method of fabricating a spatial light modulator, comprising the steps of:
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(a) forming on a glass substrate a depression in a central region thereof, a rim surrounding said depression, and pillars formed to project from said depression;
(b) diffusing impurities into one surface of a silicon substrate to a predetermined depth;
(c) further diffusing impurities into a predetermined portion of said one surface of said silicon substrate to a predetermined depth to form an impurity diffusion surface;
(d) forming an optically reflective film on said impurity diffusion surface of said silicon substrate;
(e) bonding said impurity diffusion surface and said rim of said glass substrate, to form a silicon-glass bonded substrate;
(f) wet-etching said silicon-glass bonded substrate to make said silicon substrate into a thin film;
(g) dry-etching said silicon substrate of said thin film to form a plurality of micromirrors, a torsion bar coupling and supporting the same, and a frame portion fixing both ends of said torsion bar; and
(h) bonding to said frame portion of said silicon-glass bonded substrate a silicon circuit substrate provided with a plurality of pairs of electrodes for driving said plurality of micromirrors, and circuit elements applying a drive voltage to said electrodes. - View Dependent Claims (37, 38, 39)
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40. A method of fabricating a spatial light modulator comprising the steps of:
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(a) forming a first resist pattern on a glass substrate to form pillars in a central region thereof and a first rim on the periphery thereof;
(b) forming a first metal film on said glass substrate and said first resist pattern;
(c) forming on said first metal film a second resist pattern to form micromirrors and a torsion bar;
(d) etching said first metal film using said second resist pattern;
(e) removing said second resist pattern;
(f) forming a third resist pattern in a region excluding a surface of said first rim;
(g) forming a second metal film on said first rim and said third resist pattern;
(h) forming a fourth resist pattern on said second metal film and in position opposite said first rim;
(i) etching said second metal film using said fourth resist pattern, and extending said first rim to form a second rim;
(j) removing said first, third, and fourth resist patterns; and
(k) bonding a silicon circuit substrate provided with circuit elements for driving said micromirrors and said second rim of said glass substrate. - View Dependent Claims (41, 42)
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Specification