JP2003334798A - Submerged operating microactuator and light switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To speed up operation. <P>SOLUTION: When supplying a voltage between a fixed electrode 25 and a movable electrode 17, the under surface of a connecting part 16 having the movable electrode 17 contacts with the upper surface of an insulating film 46 formed on the fixed electrode 25 by an electrostatic force. When this state is changed to a state of not supplying the voltage between the fixed electrode 25 and the movable electrode 17, the connecting part 16 separates from the upper surface of the insulating film 48. At this time, since a groove 43 is formed on the upper surface of the insulating film 46, the groove 43 becomes a guide passage for introducing peripheral liquid between the under surface of the connecting part 16 and the upper surface of the insulating film 46 for contacting with the under surface so that the peripheral liquid smoothly enters between the surfaces. Thus, the connecting part 16 separates from the insulating film 46 in a short time. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-liquid actuated microactuator and an optical switch using the same.

[0002]

2. Description of the Related Art With the progress of micromachining technology,
The importance of microactuators is increasing in various fields. An example of a field in which the microactuator is used is an optical switch used for optical communication or the like and switching an optical path. As an example of such an optical switch, Japanese Patent Application Laid-Open No. 2001-142
The optical switch disclosed in Japanese Patent Publication No. 008 can be mentioned.

The microactuator includes a fixed part and a movable part which is movable with respect to the fixed part, and the movable part is arranged in a liquid (a liquid-actuated microactuator). There is also. For example, FIG. 8 of Japanese Patent Laid-Open No. 2001-142008.
Discloses an example in which a movable part is arranged in a refractive index adjusting liquid.

Here, the optical switch disclosed in FIG. 8 of Japanese Patent Laid-Open No. 2001-142008 will be described. This optical switch is provided with an optical waveguide substrate in which optical waveguides are formed in a matrix and grooves in which mirrors can advance are formed at intersections thereof, and an actuator substrate in which microactuators and mirrors are formed. The mirror is driven by a microactuator, and when the mirror advances into the groove of the optical waveguide substrate, the light is reflected by the mirror, while when the mirror exits the groove, the light travels straight to switch the optical path. . When the mirror exits the groove, the light in the optical waveguide once enters the groove and exits the optical waveguide. When the light goes out of the waveguide, the groove is filled with a liquid having the same refractive index as the optical waveguide (refractive index adjusting liquid) in order to reduce the loss due to reflection.
Therefore, the microactuator operates in the liquid.

In the microactuator used in the optical switch disclosed in FIG. 8 of Japanese Patent Laid-Open No. 2001-142008, a plate-shaped portion whose one end side is fixed to the actuator substrate is used as the movable portion. .
A mirror is fixed to the tip side of the plate portion. When no driving force is applied, this plate-shaped portion is curved so as to warp toward the side opposite to the substrate, and when the driving force is applied, the entire surface of the plate-shaped portion on the substrate side becomes sticky on the substrate. Abut the surface of.
When the driving force is no longer applied, the plate-shaped portion returns to the curved state by bending toward the side opposite to the substrate due to the spring force (internal stress).

[0006]

As a result of research conducted by the present inventor, it has been found that the above-described conventional submersible microactuator operates very slowly. That is,
It takes a very long time to return from the state in which the entire surface of the plate-shaped portion on the substrate side is in contact with the surface on the substrate to the state in which the plate-shaped portion is warped to the side opposite to the substrate and curved by the spring force of the plate-shaped portion. There was found.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an in-liquid actuating microactuator capable of speeding up the operation and an optical switch using the same.

[0008]

As a result of further research by the present inventor, the cause of the slow operation of the conventional microactuator operating in liquid is that the viscosity of liquid is much larger than that of air. The plates that are in contact with each other when the entire surface of the plate-shaped portion on the substrate side is in contact with the surface on the substrate, and when the plate-shaped portion returns to the curved state on the side opposite to the substrate by the spring force of the plate-shaped portion. It was found that it takes time for the liquid to enter between the substrate-side surface of the plate-like portion and the substrate surface.

The present invention has been made as a result of the investigation of the cause by the present inventor, and the submerged actuating microactuator according to the first aspect of the present invention includes a fixed portion and a movable portion arranged in the liquid. A submersible microactuator capable of being positioned at a first position abutting the fixed part and at a second position distant from the fixed part, wherein the movable part is the first position. And a guide path forming structure for forming a guide path for guiding the surrounding liquid between the contact surfaces of the movable part and the fixed part which tend to separate from each other when moving from the position to the second position. is there.

The submerged actuation microactuator according to a second aspect of the present invention is the microactuator in the first aspect, wherein the guide path forming structure is a region facing the fixed part in the movable part and the movable part in the fixed part. One or more grooves formed in at least one of the facing regions of the section.

A submerged actuated microactuator according to a third aspect of the present invention is the microactuator according to the first aspect, wherein the guide path forming structure is a region of the movable part facing the fixed part and the movable part of the fixed part. One or more protrusions formed in at least one of the regions facing the section.

In a submerged actuated microactuator according to a fourth aspect of the present invention, in the first aspect, the guide path forming structure includes at least one through hole formed in the movable portion.

A submerged actuated microactuator according to a fifth aspect of the present invention comprises a fixed portion and a movable portion arranged in the liquid, wherein the movable portion has a first position in which the movable portion contacts the fixed portion and A submerged actuation microactuator that can be located at a second position away from the fixed part, wherein when the movable part is located at the first position, the movable part has a region facing the fixed part. It is configured such that only a part of them contacts the fixing portion.

The submerged actuated microactuator according to the sixth aspect of the present invention comprises a fixed part and a movable part arranged in the liquid, wherein the movable part is in a first position where it abuts on the fixed part, and An in-liquid actuating microactuator that can be located at a second position distant from the fixed part, wherein at least one of the movable part and the fixed part is present when the movable part is located at the first position. The point is a point-like or linear contact.

A submerged actuated microactuator according to a seventh aspect of the present invention comprises a fixed part and a movable part arranged in the liquid, wherein the movable part contacts the fixed part at a first position and An in-liquid actuated microactuator that can be located at a second position away from the fixed part, wherein the movable part has a curved part that is warped toward the fixed part and has a spring property when not receiving a force. When the movable portion moves from the second position to the first position, the tip portion of the bending portion first comes into contact with the fixed portion.

An in-liquid actuating microactuator according to an eighth aspect of the present invention is the microactuator in any one of the first to seventh aspects, wherein the movable portion is made of a thin film.

A submerged actuation microactuator according to a ninth aspect of the present invention is the microactuator in any one of the first to eighth aspects, wherein the movable portion constitutes a cantilever.

A submerged actuated microactuator according to a tenth aspect of the present invention is the microactuator according to the ninth aspect, wherein the fixed end of the movable portion is provided with a leg portion having a rising portion rising from the fixed portion. It is fixed against.

An optical switch according to an eleventh aspect of the present invention includes the submerged actuating microactuator according to any one of the first to tenth aspects, and a mirror provided on the movable portion. .

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An in-liquid actuated microactuator and an optical switch according to the present invention will be described below with reference to the drawings.

[First Embodiment]

FIG. 1A is a schematic plan view schematically showing a submersible microactuator 1 and a mirror 2 driven by the microactuator 1 according to the first embodiment of the present invention. For convenience of explanation, as shown in FIG. 1A, an X axis and a Y axis which are orthogonal to each other are defined (see FIG. 8A described later,
The same applies to FIGS. 14 and 17. ). In the X-axis direction, the arrow direction is + X direction and the opposite direction is-.
Call it the X direction. The XY plane is parallel to the surface of the substrate. FIG. 1B shows a fixed electrode 25 provided on the substrate 11.
It is a schematic plan view which shows typically. In FIG. 1B, a part of the outer shape of the connection portion 16 and the beam portions 14 and 15 is also shown by an imaginary line in order to clarify the positional relationship in a plan view.

FIGS. 2 and 3 are each a schematic view of a cross section taken along line X1-X2 in FIG. 1 (a). FIG. 4 and FIG. 5 are each a diagram schematically showing a cross section taken along line Y1-Y2 in FIG. 2 and 4 show a state in which the drive signal is not supplied, and FIGS. 3 and 5 show a state in which the drive signal is supplied.

The microactuator 1 according to this embodiment has a substrate 11 such as a silicon substrate and leg portions 12 and 13.
And two strip-shaped beam portions 1 mainly extending in the X-axis direction
4, 15 and the connecting portions 16 provided at the tips (free ends, ends in the + X direction) of the beam portions 14 and 15 and having a rectangular shape in plan view for mechanically connecting them, the movable electrode 17, And a fixed electrode 25.

The beam portions 14 and 15 are respectively made of SiN on the lower side.
The film 21 and the upper Al film 22 are laminated to form a two-layer thin film. The material and the number of layers of the beam portions 14 and 15 are not limited to this, and for example, another insulating film may be used instead of the SiN film 21, or another conductive film may be used instead of the Al film 22. You may use. In addition, as shown in FIGS. 2 and 4, the beam portions 14 and 15 are warped upward (on the side opposite to the substrate 11) in the state where the drive signal is not supplied.

The connecting portion 16 is formed by the SiN film 21 and the Al film 22 forming the beam portions 14 and 15 extending continuously as they are. The rectangular region of the Al film 22 over almost the entire connection portion 16 serves as the movable electrode 17. Further, the connecting portion 16 has an A as a driven body.
A mirror 2 made of u, Ni or another metal is provided. Although not shown in the drawing, an insulating film is formed between the mirror 2 and the Al film 22 as needed.

As shown in FIGS. 1 to 3, the beam portions 14, 1
The end portion (fixed end) in the −X direction of 5 is separated from the substrate 11 via a wiring pattern 24 (not shown in FIG. 1) made of an Al film formed on an insulating film 23 such as a silicon oxide film on the substrate 11. It is mechanically connected to the substrate 11 via legs 12 and 13 each having a rising portion that rises. In the present embodiment, the leg portions 12 and 13 are formed by the SiN film 21 and the Al film 22 forming the beam portions 14 and 15 extending continuously as they are. The Al film 22 is also used as a wiring that electrically connects the movable electrode 17 to the wiring pattern 24, and the SiN film 2 is formed on the leg portions 12 and 13.
The wiring patterns 24 are electrically connected to each other through the openings formed in 1.

As can be seen from the above description, in the present embodiment, the beam portions 14 and 15 and the connecting portion 16 constitute a cantilever beam as a movable portion as a whole. Further, in the present embodiment, the substrate 11, the insulating film 23, the fixed electrode 25 and the insulating film 26, which will be described later, form a fixed portion. In the present embodiment, mechanically stable support is possible by using the two beam portions 14 and 15, but the number of beam portions may be one or three or more. In addition, in this embodiment, as shown in FIG.
When the plurality of microactuators 1 are arranged two-dimensionally on the substrate 11 as shown in FIG. 7, the arrangement density of the microactuators 5 should be increased. It is like this. However, in the present invention, the number of microactuators 1 mounted on the substrate 11 may be an arbitrary number of 1 or more. FIG. 7 is a schematic plan view schematically showing an arrangement example of the plurality of microactuators 1. In addition, in the present invention, the movable portion is not necessarily limited to the cantilever beam, and for example, a double-supported structure or the like can be adopted.

As shown in FIGS. 1 to 5, on the insulating film 23 on the substrate 11, a fixed electrode 25 made of an Al film is formed in a rectangular region facing the movable electrode 17.
The fixed electrode 25 is covered with an insulating film 26 such as a PSG film that extends over the insulating film 23. Although not shown in the drawing, the Al film forming the fixed electrode 25 also extends as a wiring pattern, and when used together with the wiring pattern 24, a voltage is applied between the fixed electrode 25 and the movable portion 17. , Can be applied as a drive signal. When this voltage is applied, an electrostatic force (driving force) acts between the fixed electrode 25 and the movable electrode 17, which resists the spring force (internal stress) of the beam portions 14 and 15 and is shown in FIGS. It becomes a state.
On the other hand, if this voltage is not applied, the electrostatic force (driving force) does not act between the fixed electrode 25 and the movable electrode 17, and the spring force (internal stress) of the beam portions 14 and 15 causes the electrostatic force (driving force) to occur. Return to the state shown in. A drive circuit that generates this drive signal in response to a control signal from the outside may be mounted on the substrate 11.

As described above, in this embodiment, the driving is performed by the electrostatic force generated by the driving signal. However,
The present invention may be configured to be driven by another driving force such as a magnetic force or a Lorentz force, or a driving force that is a combination of any two or more kinds.

In this embodiment, when the movable portion is located at the position (first position) shown in FIG. 3 due to the electrostatic force acting between the fixed electrode 25 and the movable electrode 17, the movable portion is fixed. It is configured such that only a part of the area facing the portion contacts the fixing portion. Specifically, in the present embodiment, the leg portions 12 and 13 having the rising portions are adopted, and the fixed electrode 25 and the movable electrode 17 are provided on the tip side of the beam portions 14 and 15 as described above. Since it is arranged at the position, as shown in FIGS. 3 and 5, when the electrostatic force acts between the fixed electrode 25 and the movable electrode 17, the region where the movable portion and the fixed portion contact each other is: A rectangular area (connecting portion 16) on the lower surface of the SiN film 21 facing the movable electrode 17.
(Almost the entire area of the lower surface of the above) and the rectangular area of the upper surface of the insulating film 26 facing the fixed electrode 25, and unlike the conventional microactuator described above, the lower surfaces of the beam portions 14 and 15 are in contact with the fixed portion without sticking. There is nothing to do.

Next, an example of a method of manufacturing the microactuator 1 according to this embodiment will be described with reference to FIG. FIG. 6 is a schematic sectional view schematically showing each step of this manufacturing method, and corresponds to FIG.

First, a silicon oxide film 23 is formed on the upper surface of the silicon substrate 11 by thermal oxidation, an Al film is deposited thereon by vapor deposition or sputtering, and then the Al film is fixed by a photolithographic etching method. 25, the wiring pattern 24 and other wiring patterns are patterned (FIG. 6A). Then, the PSG film 26 is formed on the substrate in this state by the atmospheric pressure CVD method or the like (FIG. 6B).

Next, after forming openings corresponding to the contact portions of the leg portions 12 and 13 in the PSG film 26, a sacrificial layer resist 30 is applied to the entire surface of the substrate, and the resist 30 is applied.
And an opening 30a corresponding to the contact portion of the legs 12 and 13.
Are formed by a photolithographic etching method (FIG. 6).
(C)).

After that, the leg portions 12 and 13 and the beam portions 14 and 15
And the SiN film 21 to be the connection portion 16 is subjected to plasma CV.
After being formed by the D method or the like, patterning is performed by the photolithographic etching method to obtain those shapes. At this time, openings are formed in the contact portions of the leg portions 12 and 13. Next, after depositing the Al film 22 to become the leg portions 12 and 13, the beam portions 14 and 15 and the connection portion 16 by vapor deposition or sputtering, patterning is performed by photolithography etching to form them (FIG. 6 ( d)).

Next, a resist 31 serving as a sacrifice layer is thickly applied over the entire surface of the substrate in the state shown in FIG. 6D (FIG. 6).
(E)). Here, after exposing and developing the resist 31, a region where the mirror 2 is to be grown is formed in the resist 31, and then Au, Ni or another metal to be the mirror 2 is grown by electrolytic plating. Finally, the resists 30 and 31 are removed by the plasma ashing method or the like. This allows
The microactuator 1 according to this embodiment is completed.

As described above, the film 21 and the film 22 are formed by removing the resists 30 and 31 from the beam portion 1.
It is performed under the condition that the films 4 and 15 warp upward due to the stress during the film formation.

When the microactuator 1 according to the present embodiment is used, the space above the substrate 11 is filled with a liquid such as a refractive index adjusting liquid, and the movable portion is liquid, as in a seventh embodiment to be described later. It is placed inside.

According to this embodiment, as described above,
When a voltage is applied between the fixed electrode 25 and the movable electrode 17, the movable portion comes into contact with the fixed portion due to the electrostatic force between the two, and the connecting portion 16 is positioned on the substrate 11 side as shown in FIGS. 3 and 5. Located in. From this state, when no voltage is applied between the fixed electrode 25 and the movable electrode 17, the beam portion 1
Due to the internal stress of 4 and 15, the movable portion is separated from the fixed portion, and the connecting portion 16 is located at a position away from the substrate 11 as shown in FIGS. 2 and 4. When the movable part is about to move from the position shown in FIGS. 3 and 5 to the position shown in FIGS. 2 and 4, the surrounding liquid tries to enter the space between the movable part and the substrate 11.

In the present embodiment, as described above, in the state shown in FIGS. 3 and 5 in which the electrostatic force is applied between the fixed electrode 25 and the movable electrode 17, the movable portion and the fixed portion are separated from each other. The contact area is SiN facing the movable electrode 17.
The rectangular area of the lower surface of the film 21 (almost the entire area of the lower surface of the connection portion 16) and the rectangular area of the upper surface of the insulating film 26 facing the fixed electrode 25 are limited, and unlike the above-described conventional microactuator, the beam portion is provided. The bottom surfaces of 14 and 15 do not come into contact with the fixed parts. Therefore, in FIG.
When the movable part is about to move from the position shown in FIG. 5 to the position shown in FIGS. 2 and 4, the surrounding liquid is more likely to enter the space between the movable part and the substrate 11 than the conventional microactuator. It is done smoothly. Therefore, according to the present embodiment, from the state shown in FIG. 3 and FIG.
Also, the transition to the state shown in FIG. 4 is performed in a shorter time, and the operation speed can be increased.

[Second Embodiment]

FIG. 8A is a schematic plan view schematically showing the submerged actuated microactuator 41 and the mirror 2 driven by the microactuator 41 according to the second embodiment of the present invention. FIG. 8B shows the fixed electrode 25 installed on the substrate 11.
FIG. 6 is a schematic plan view schematically showing a spacer film 42.
In FIG. 8B, a part of the outer shape of the connecting portion 16 and the beam portions 14 and 15 is also shown by an imaginary line in order to clarify the positional relationship in a plan view. 9 and 10 are respectively shown in FIG.
It is a figure which shows typically the cross section along the X3-X4 line in (a). 11 and 12 are each a diagram schematically showing a cross section taken along line Y3-Y4 in FIG. 9 and 11 show a state in which the drive signal is not supplied, FIG.
0 and FIG. 12 show a state in which the drive signal is supplied.

In these figures, the same or corresponding elements as those in FIGS. 1 to 5 are designated by the same reference numerals, and their duplicated description will be omitted.

In the first embodiment, the fixed electrode 25
In the state where the electrostatic force is applied between the movable electrode 17 and the movable electrode 17 (see FIGS. 3 and 5), S that faces the movable electrode 17
The rectangular area on the lower surface of the iN film 21 (substantially the entire area of the lower surface of the connecting portion 16) and the rectangular area on the upper surface of the insulating film 26 facing the fixed electrode 25 are in contact with each other. A guide passage forming structure for forming a guide passage for guiding the surrounding liquid between the contact surfaces when returning to the state shown is not provided.

In this embodiment, as such a guide path forming structure, as shown in FIGS. 11 and 12, the connecting portion 16 is formed.
By forming a plurality of grooves 43 in the region on the insulating film 46 facing the region of the lower surface of the above, the operation speed is further increased.

In this embodiment, as shown in FIGS. 9 to 12, an insulating film 46 is formed instead of the insulating film 26 shown in FIGS. 2 to 5, and the spacer film 42 is formed below the fixed electrode 25.
Are formed. Although not shown in the drawing, the insulating film 46 is composed of a two-layer film made of the same material. The spacer film 42 is formed on the insulating film 23 and is covered with a lower layer of the insulating film 46 which extends over the insulating film 23. In the present embodiment, the fixed electrode 25 is formed on the lower layer of the insulating film 46 and is covered with the upper layer of the insulating film 46. The upper layer of the insulating film 46 extends to the lower layer of the insulating film 46.

In this embodiment, the fixed electrode 25 has a structure shown in FIG.
As shown in (b), notches 25a to 25
25d is formed. Notches 25a, 2
5b extends in the -X direction from the + X side of the rectangular shape, and the cutouts 25c and 25d extend in the + X direction from the -X side so as to face the cutouts 25a and 25b, respectively. When the notch is formed from the + X side to the −X side of the rectangular shape, a region that cannot be electrically connected is generated. Therefore, diagonal regions are formed between the notches 25a and 25c and between the notches 25b and 25d. It is left. As shown in FIG. 8B, the shape of the spacer film 42 is almost the same as the shape of the fixed electrode 25, and the size thereof is slightly larger than that of the fixed electrode 25. The shape of the groove 43 formed in the area on the insulating film 46 facing the area of the lower surface of the connection portion 16 in plan view is a copy of the shape of the cutout portions 25 a to 25 d of the fixed electrode 25. As shown in FIGS. 11 and 12, the depth is substantially equivalent to the total film thickness of the fixed electrode 25 and the spacer film 42.

Further, in this embodiment, as shown in FIG. 8A, the movable electrode 17 is also formed with notches 17a to 17d. This is to prevent unnecessary electrostatic force from acting when the substrate 11 is kept at a predetermined potential, but the movable electrode 17 may be left in a rectangular shape without forming a notch.

Here, an example of a method of manufacturing the microactuator 41 according to this embodiment will be described with reference to FIG. FIG. 13 is a schematic sectional view schematically showing each step of this manufacturing method, and corresponds to FIG. 9.

First, a silicon oxide film 23 is formed on the upper surface of the silicon substrate 11 by thermal oxidation, an Al film is deposited thereon by vapor deposition or sputtering, and then the Al film is formed by a photolithographic etching method as a spacer film. 42 and the wiring pattern 24 are patterned (see FIG. 13).
(A)).

Next, on the substrate in the state shown in FIG. 13A, P which will be the lower layer of the insulating film 46 is formed by the atmospheric pressure CVD method or the like.
An SG film is formed. Next, after depositing an Al film on the PSG film by vapor deposition or sputtering, the Al film is patterned into a fixed electrode 25 and a wiring pattern (not shown) for the fixed electrode 25 by photolithographic etching. . Then, a PSG film to be an upper layer of the insulating film 46 is formed by the atmospheric pressure CVD method or the like (FIG. 13).
(B)).

Next, after forming openings corresponding to the contact portions of the leg portions 12 and 13 in the insulating film (two-layer PSG film) 46, a resist 30 serving as a sacrificial layer is applied on the entire surface of the substrate,
Openings 30a corresponding to the contact portions of the leg portions 12 and 13 are formed in the resist 30 by a photolithographic etching method (FIG. 13C).

After that, the leg portions 12 and 13 and the beam portions 14 and 15
And the SiN film 21 to be the connection portion 16 is subjected to plasma CV.
After being formed by the D method or the like, patterning is performed by the photolithographic etching method to obtain those shapes. At this time, openings are formed in the contact portions of the leg portions 12 and 13. Next, after depositing the Al film 22 to become the leg portions 12 and 13, the beam portions 14 and 15, and the connection portion 16 by vapor deposition or sputtering, patterning is performed by photolithography etching to form them (FIG. d)).

Next, a resist 31 serving as a sacrifice layer is thickly applied over the entire surface of the substrate in the state shown in FIG. 13D (FIG. 13).
(E)). Here, after exposing and developing the resist 31, a region where the mirror 2 is to be grown is formed in the resist 31, and then Au, Ni or another metal to be the mirror 2 is grown by electrolytic plating. Finally, the resists 30 and 31 are removed by the plasma ashing method or the like. This allows
The microactuator 41 according to this embodiment is completed.

As described above, the film 21 and the film 22 are formed when the resists 30 and 31 are removed.
It is performed under the condition that the films 4 and 15 warp upward due to the stress during the film formation.

According to the present embodiment, when a voltage is applied between the fixed electrode 25 and the movable electrode 17, an electrostatic force between the fixed electrode 25 and the movable electrode 17 causes the connecting portion 16 to move as shown in FIGS.
The lower surface of the above contacts the upper surface of the insulating film 46 facing the fixed electrode 25 (the shape thereof is a transfer of the above-described shape of the fixed electrode 25). From this state, when no voltage is applied between the fixed electrode 25 and the movable electrode 17,
Due to the internal stress of the beam portions 14 and 15, the state returns to the state shown in FIGS. 9 and 11, and the lower surface of the connection portion 16 separates from the upper surface of the insulating film 46 that was in contact therewith. At this time, the groove 43 described above serves as a guide path for guiding the surrounding liquid between the lower surface of the connecting portion 16 and the upper surface of the insulating film 46 with which the connecting portion 16 is in contact, and the surrounding liquid smoothly enters between them.

Therefore, according to the present embodiment, the transition from the state shown in FIGS. 10 and 12 to the state shown in FIGS. 9 and 11 is much shorter than that in the first embodiment. Therefore, the operation speed can be further increased.

When the extending direction of the groove 43 is set to the X-axis direction (the extending direction of the beam portions 14 and 15) as in the present embodiment, the connection portion 16 is more separated from the upper surface of the insulating film 46. It is a short time, which is preferable. However, the groove 43
The direction of is not limited to this direction. Further, the number of grooves 43 and the like are not limited. In the present embodiment, as described above, the cutout portions 25a of the fixed electrode 25,
The region between 25c and the region between the cutouts 25b and 25d are slanted, and since this shape is transferred to the shape of the groove 43, compared with the case where the region between them is extended in the Y-axis direction. Accordingly, the liquid can be more smoothly introduced, and the connection portion 16 can be separated from the upper surface of the insulating film 46 in a shorter time, which is preferable.

Further, in this embodiment, the spacer film 42 is used.
Is formed, the depth of the groove 43 is increased by the film thickness of the spacer film 42. When the depth of the groove 43 is increased in this way, the liquid can be guided more smoothly, which is preferable. Although the present embodiment is an example in which only one layer of the spacer film 42 is inserted, for example, if two or more spacer films are inserted between the fixed electrode 25 and the insulating film 23, the groove 4 can be formed.
The depth of 3 can be made deeper. However, the spacer film 42 does not necessarily have to be formed. in this case,
For example, the manufacturing process basically the same as the manufacturing process of the first embodiment described above may be adopted, and the patterning of the fixed electrode 25 may be performed in the shape shown in FIG. 8B.

Although the groove 43 is formed on the fixed portion side in this embodiment, it is on the movable portion side (that is, the connecting portion 1).
You may form a groove | channel in the lower surface (6). Also in this case, the same effect as this embodiment can be obtained.

By the way, also in the first embodiment, the resistance of the liquid in the liquid increases in proportion to the area of the electrode. Therefore, if the electrode area is reduced, the resistance of the liquid is reduced and high-speed operation is possible. It will be possible. However, if the electrode area is reduced,
The applied voltage required to overcome the internal stress of the beam portions 14 and 15 and clamp the fixed electrode 25 and the movable electrode 17 is inversely proportional to the area of the electrode, and thus requires a high voltage. To increase the applied voltage, it is necessary to increase the breakdown voltage,
There is also a problem that the drive circuit becomes large. On the other hand, in the present embodiment, since the electrode area does not have to be made so small, the problem of increase in applied voltage does not occur. This point is the same for each embodiment described later.

[Third Embodiment]

FIG. 14 is a schematic plan view schematically showing a submersible microactuator 51 and a mirror 2 driven by the microactuator 51 according to a third embodiment of the present invention.
15 and 16 are schematic views each showing a cross section taken along line X5-X6 in FIG. FIG. 15 shows a state where the drive signal is not supplied, and FIG. 16 shows a state where the drive signal is supplied. In these figures, FIG.
Elements that are the same as or correspond to the elements in FIG. 5 are assigned the same reference numerals, and duplicate descriptions thereof are omitted.

The present embodiment is different from the first embodiment in that the tip of the connecting portion 16 is provided with a bending portion 52 which is bent downward (to the side of the substrate 11) in a state where no force is applied and which has a spring property. It is only the point provided.

The curved portion 52 has a shape extending in a strip shape in the + X direction from the tip of the connecting portion 16 in a plan view, and is a two-layer thin film in which a lower Al film 53 and an upper SiN film are laminated. As shown in FIG. 15, it is configured to bend downward without being subjected to a force. The upper SiN film forming the curved portion 52 is formed by continuously extending the SiN film 21 of the connection portion 16 as it is. When a voltage is applied between the fixed electrode 25 and the movable electrode 17, the curved portion moves when the movable portion moves from the position shown in FIG. 15 apart from the substrate 11 to the position shown in FIG. 16 on the substrate 11 side. The tip portion of 52 is first brought into contact with the fixing portion (the insulating film 26 in the present embodiment). In the present embodiment, after the tip portion of the bending portion 52 first comes into contact with the fixing portion, the bending portion 52 bends so as to reduce the degree of bending, whereby the bending portion 5
Due to the spring force generated in step 2, the movable part is stopped in a state where there is a gap between the lower surface of the connecting portion 16 and the upper surface of the insulating film 26 as shown in FIG. In this state, the movable portion is provided only at the tip portion of the bending portion 52.
The lines are in contact with each other and extend in a direction perpendicular to the paper surface.

The microactuator 51 according to this embodiment can be manufactured by a manufacturing method in which a part of the manufacturing method shown in FIG. 6 is modified as follows. That is, after the step shown in FIG.
After the Al film to be the I film 53 is deposited by vapor deposition or sputtering, the Al film 53 is patterned by photolithography. Next, FIG. 6 (d)
The subsequent steps may be performed. However, when the SiN film 21 is patterned, the curved portion 53 is left.

According to the present embodiment, as shown in FIG. 16, between the lower surface of the connecting portion 16 and the upper surface of the insulating film 26, the movable electrode 17 is attracted to the fixed electrode 25 by electrostatic force. There is a gap. When the voltage is not applied between the fixed electrode 25 and the movable electrode 17 from the state shown in FIG. 16, the movable portion moves away from the substrate 11 and the state shown in FIG.
When returning to the state shown in (4), the gap serves as a passage for the surrounding liquid, and the surrounding liquid smoothly enters between the lower surface of the connecting portion 16 and the upper surface of the insulating film 26. The tip of the curved portion 53 only linearly contacts the insulating film 26,
Since the entire curved portion 53 is not in contact with the upper surface of the insulating film 26, the liquid smoothly enters under the curved portion 53.

When no voltage is applied between the fixed electrode 25 and the movable electrode 17 in the state shown in FIG. 16, at the beginning, not only the spring force of the beam portions 14 and 15 but also the spring force of the bending portion 53. The force also moves the movable part upward. Therefore, as compared with the first embodiment, the movable portion is separated from the substrate 11 by a large force.

As described above, according to the present embodiment, the effect that both the liquid smoothly enters and the movable portion moves away from the substrate 11 with a large force are combined, and the first Compared with the embodiment described above, the transition from the state shown in FIG. 16 to the state shown in FIG. 15 is performed in a significantly shorter time, and the operation speed can be further increased.

By the way, when the force acting between the fixed electrode 25 and the movable electrode 17 is set to a considerably large value, the spring force of the bending portion 53 is resisted and the connection is made in the same manner as in the first embodiment. The lower surface of the portion 16 comes into contact with the upper surface of the insulating film 26. In this case, the liquid entry as described above is the same as that in the first embodiment, but the movable part is separated from the substrate 11 by a large force corresponding to the spring force of the bending part 53. After all, as compared with the first embodiment, the transition from the state shown in FIG. 16 to the state shown in FIG. 15 is performed in a remarkably short time, and the operation speed can be further increased.

A plurality of microactuators 51
When the substrates are arranged two-dimensionally on the substrate 11, it is not necessary to widen the arrangement pitch due to the curved portion 53, and the same high arrangement density as in the case of FIG. 7 can be secured.

[Fourth Embodiment]

FIG. 17 is a schematic plan view schematically showing an in-liquid actuating microactuator 61 and a mirror 2 driven by the same according to a fourth embodiment of the present invention.
In FIG. 17, elements that are the same as or correspond to the elements in FIGS. 14 to 16 are assigned the same reference numerals, and overlapping descriptions thereof are omitted.

The present embodiment is different from the third embodiment in that the curved portion 52 is removed and two curved portions 52a and 52b corresponding to the curved portion 52 are arranged on both sides of the connecting portion 16. It is only the point. The curved portion 52a has a lower A
The I film 53a and the upper SiN film are laminated to form a two-layer thin film, and are curved toward the substrate 11 from the base end side to the tip end side. Similarly, the curved portion 52b also includes the lower Al film 5
3b and an upper SiN film are laminated to form a two-layer thin film, which is curved toward the substrate 11 from the base end side to the tip end side. The SiN film on the upper side of the curved portions 52a and 52b is formed by continuously extending the SiN film 21 of the connecting portion 16.

Also according to this embodiment, the same advantages as those of the third embodiment can be obtained.

[Fifth Embodiment]

18 and 19 are schematic sectional views schematically showing a submerged actuated microactuator 71 and a mirror 2 driven by the microactuator 71 according to a fifth embodiment of the present invention, and FIGS. It corresponds to each. Figure 1
8 shows a state in which the drive signal is not supplied, and FIG. 19 shows a state in which the drive signal is supplied. FIG. 20 is a schematic plan view showing only the protrusion 72 and the fixed electrode 25. In these figures, the same or corresponding elements as those in FIGS. 1 to 5 are designated by the same reference numerals, and the duplicated description thereof will be omitted.

The difference of this embodiment from the first embodiment is that the insulating film 26 facing the lower surface of the connecting portion 16 is provided as the guide path forming structure described in connection with the second embodiment. The point is that the projection 72 is formed on the upper surface of the. In the present embodiment, the four protrusions 72 are arranged at the positions corresponding to the vicinity of the four corners of the connecting portion 16, but the number and position thereof are not limited to this.

The microactuator 71 according to this embodiment can be manufactured by a manufacturing method in which a part of the manufacturing method shown in FIG. 6 is modified as follows. That is, after the step shown in FIG. 6B, a SiN film to be the protrusion 72 is formed by plasma CVD or the like,
The projections 7 are patterned by the photolithography etching method.
The shape is 2. Next, the steps after FIG. 6C may be performed.

According to this embodiment, when a voltage is applied between the fixed electrode 25 and the movable electrode 17, the lower surface of the connecting portion 16 is projected by the projection 72 due to the electrostatic force between the two. Contacting the upper surface of the insulating film 26 and the lower surface of the connecting portion 16
There is a gap between it and the top surface of. Therefore, the movable portion comes into point contact with the fixed portion. From this state,
When the voltage is not applied between the fixed electrode 25 and the movable electrode 17, the internal stress of the beam portions 14 and 15 returns the state to that shown in FIG. 18, and the lower surface of the connection portion 16 from the substrate 11 side. Come away. At this time, the gap serves as a passage for the surrounding liquid, the surrounding liquid smoothly enters between the lower surface of the connecting portion 16 and the upper surface of the insulating film 26, and the protrusion 72 and the lower surface of the connecting portion 16 are separated from each other. Liquid smoothly enters between the contact surfaces.

Therefore, according to the present embodiment, as compared with the first embodiment, the state shown in FIG.
The transition to the state shown in 8 is performed in a remarkably short time, and the operation speed can be further increased.

Although the projection 72 is formed on the fixed portion side in the present embodiment, the projection may be formed on the movable portion side (that is, the lower surface of the connecting portion 16). Also in this case, the same effect as this embodiment can be obtained.

[Sixth Embodiment]

FIG. 21 is a schematic plan view schematically showing an in-liquid actuating microactuator 81 and a mirror 2 driven by the same according to the sixth embodiment of the present invention.
22 and 23 are each a diagram schematically showing a cross section taken along line Y5-Y6 in FIG. 22 shows a state in which the drive signal is not supplied, and FIG. 23 shows a state in which the drive signal is supplied. In these figures, FIG.
Elements that are the same as or correspond to the elements in FIG. 5 are assigned the same reference numerals, and duplicate descriptions thereof are omitted.

The difference of this embodiment from the first embodiment is that the through hole 82 is formed in the connecting portion 16 as the guide path forming structure described in relation to the second embodiment. It is only the point. The number and position of the through holes 82 are not limited to the illustrated example.

The microactuator 81 according to this embodiment can be manufactured by a manufacturing method in which a part of the manufacturing method shown in FIG. 6 is modified as follows. That is, in the step shown in FIG. 6D, the SiN film 21
The opening corresponding to the through hole 82 may be formed during the patterning of the above, and the opening corresponding to the through hole 82 may be formed during the patterning of the Al film 22.

According to the present embodiment, when a voltage is applied between the fixed electrode 25 and the movable electrode 17, an electrostatic force between the two causes the lower surface of the connecting portion 16 to be an insulating film, as shown in FIG. Contact the upper surface of 26. From this state, the fixed electrode 2
When no voltage is applied between the movable electrode 17 and the movable electrode 17, the internal stress of the beam portions 14 and 15 returns to the state shown in FIG. 22, and the lower surface of the connection portion 16 is in contact with the insulating film. Away from the top surface of 26. At this time, the above-described through hole 82 serves as a guide path for guiding the surrounding liquid between the lower surface of the connecting portion 16 and the upper surface of the insulating film 26 which is in contact therewith, and the surrounding liquid smoothly enters between them. .

Therefore, according to the present embodiment, as compared with the first embodiment, the state shown in FIG.
The transition to the state shown in 2 is performed in a remarkably short time, and the operation speed can be further increased.

[Seventh Embodiment]

24 and 25 are schematic cross-sectional views each schematically showing an optical switch according to the seventh embodiment of the present invention. FIG. 24 shows a state where the drive signal is not supplied, and FIG. 25 shows a state where the drive signal is supplied. 24 and 25, the structure of the microactuator 1 is greatly simplified. Figure 2
6 is a schematic perspective view schematically showing the optical waveguide substrate 90 in FIGS. 24 and 25.

The optical switch according to the present embodiment includes a submerged actuating microactuator 1 shown in FIGS. 1 to 5 according to the first embodiment and a mirror 2 mounted thereon.
And an optical waveguide substrate 90.

In the present embodiment, the optical waveguide substrate 90 is
As shown in FIG. 26, it has four optical waveguides 91 to 94 that propagate the light to be switched. Optical waveguide substrate 90
Has a groove 96 having a width of, for example, about several tens of μm at the center,
6, the end faces 91a, 92a of the optical waveguides 91 to 94,
93b and 94b are exposed. End face 91a and end face 9
As shown in FIGS. 24 and 25, the distance between the mirror 2 and the end surface 93b and the distance between the end surface 93b and the end surface 94b are designed to be covered by the reflecting surface of the mirror 2.

As shown in FIGS. 24 and 25, the optical waveguide substrate 90 is installed on the substrate 11 of the microactuator 1, and the space between the waveguide substrate 90 and the substrate 11 and the groove 96 communicating with the space are provided. In the space of the
2 is enclosed. The substrate 11 and the optical waveguide substrate 9
The zero is aligned so that the mirror 2 can be inserted into the groove 96.

Fixed electrode 25 of microactuator 1
In a state in which a voltage is applied between the movable electrode 17 and the movable electrode 17 (not shown in FIGS. 24 and 25), as shown in FIG. 25, the mirror 2 causes the end faces 93b, 94 of the optical waveguides 93, 94.
It is located below b. Therefore, for example, the optical waveguide 93
When the light is incident from the end face 93a of the optical waveguide 93, the light propagating through the optical waveguide 93 is emitted from the end face 93b, is incident on the end face 92a of the optical waveguide 92 which is opposite to the light, propagates through the optical waveguide 92 and is emitted from the end face 92b. It Further, for example, when light is incident from the end face 91b of the optical waveguide 91, the light propagating through the optical waveguide 91 is emitted from the end face 91a, enters the end face 94b of the optical waveguide 94 which is opposite to the light, and propagates through the optical waveguide 94. Then, the light is emitted from the end surface 94a.

On the other hand, when no voltage is applied between the fixed electrode 25 and the movable electrode 17 of the microactuator 1, as shown in FIG.
It is located so as to cover the end surfaces 93b, 94b of the 3, 94.
Therefore, for example, when light is incident from the end surface 93a of the optical waveguide 93, the light propagating through the optical waveguide 93 is converted into the end surface 93b.
From the optical waveguide 94, is reflected by the mirror 2, enters the end surface 94 b of the optical waveguide 94, propagates through the optical waveguide 94,
It is emitted from a. In addition, for example, when light is incident from the end face 91b of the optical waveguide 91, the light propagating in the optical waveguide 91 is emitted from the end face 91a, reflected by the mirror 2, and then incident on the end face 92a of the optical waveguide 92 to guide light. Waveguide 92
And is emitted from the end face 92b.

According to the present embodiment, since the microactuator 1 according to the first embodiment is used, it is possible to speed up the above-mentioned optical path switching operation.

In the present embodiment, the microactuator 1 may be replaced with any of the microactuators 41, 51, 61, 71, 81 according to the second to sixth embodiments. In that case, it is possible to further speed up the optical path switching operation.

The present embodiment is an example in which the optical waveguide substrate 90 has one intersection of optical waveguides, and accordingly, there is one mirror 2 and one microactuator. However, for example, by forming the optical waveguides in a two-dimensional matrix on the optical waveguide substrate 90, the intersections of the optical waveguides are arranged in a two-dimensional matrix, and a plurality of microactuators are arranged on the substrate 11 accordingly. The mirrors 2 arranged in a dimensional manner and located at each intersection of the optical waveguides may be driven by individual microactuators.

Although the respective embodiments of the present invention and the modifications thereof have been described above, the present invention is not limited to these embodiments and modifications. For example, the submerged microactuator according to the present invention can be used in various applications other than optical switches.

[0100]

As described above, according to the present invention,
It is possible to provide an in-liquid actuated microactuator capable of speeding up the operation.

Further, according to the present invention, it is possible to provide an optical switch capable of speeding up the optical path switching operation.

[Brief description of drawings]

FIG. 1 (a) is a schematic plan view schematically showing a submersible microactuator and a mirror driven by the microactuator according to the first embodiment of the present invention, and FIG. 1 (b) is provided on a substrate. It is a schematic plan view which shows typically the fixed electrode thus obtained.

FIG. 2 FIG. 1 in a state in which a drive signal is not supplied.
It is a figure which shows typically the cross section along the X1-X2 line in (a).

FIG. 3 is a diagram in which a drive signal is being supplied.
It is a figure which shows typically the cross section along the X1-X2 line in (a).

FIG. 4 FIG. 1 in a state in which a drive signal is not supplied.
It is a figure which shows typically the cross section along the Y1-Y2 line in (a).

FIG. 5 FIG. 1 in a state where a drive signal is supplied.
It is a figure which shows typically the cross section along the Y1-Y2 line in (a).

FIG. 6 is a schematic cross-sectional view schematically showing each step of the method for manufacturing the microactuator shown in FIGS.

FIG. 7 is a schematic plan view schematically showing an arrangement example of a plurality of microactuators.

FIG. 8 (a) is a schematic plan view schematically showing an in-liquid actuated microactuator and a mirror driven by the same according to a second embodiment of the present invention, and FIG. 8 (b) is provided on a substrate. It is a schematic plan view which shows typically the fixed electrode and spacer film which were obtained.

FIG. 9 is a diagram illustrating a state in which a drive signal is not supplied.
It is a figure which shows typically the cross section along the X3-X4 line in (a).

FIG. 10 FIG. 8 in a state where a drive signal is supplied.
It is a figure which shows typically the cross section along the X3-X4 line in (a).

FIG. 11 is a diagram schematically showing a cross section taken along line Y3-Y4 in FIG. 8A in a state where a drive signal is not supplied.

FIG. 12 FIG. 8 in a state where a drive signal is supplied.
It is a figure which shows typically the cross section along the Y3-Y4 line in (a).

FIG. 13 is a schematic cross-sectional view schematically showing each step of the method for manufacturing the microactuator shown in FIGS. 8 to 12.

FIG. 14 is a schematic plan view schematically showing an in-liquid actuated microactuator and a mirror driven by the same according to a third embodiment of the present invention.

FIG. 15 is a diagram schematically showing a cross section taken along line X5-X6 in FIG. 14 in a state where a drive signal is not supplied.

FIG. 16 FIG. 1 in a state where a drive signal is supplied.
It is a figure which shows typically the cross section along the X5-X6 line in FIG.

FIG. 17 is a schematic plan view schematically showing an in-liquid actuated microactuator and a mirror driven by the same according to a fourth embodiment of the present invention.

FIG. 18 shows a state in which a drive signal is not supplied,
It is a schematic sectional drawing which shows typically the submerged actuation microactuator and the mirror driven by this by the 5th Embodiment of this invention.

FIG. 19 is a schematic cross-sectional view schematically showing an in-liquid actuated microactuator and a mirror driven by the same according to a fifth embodiment of the present invention in a state where a drive signal is supplied.

FIG. 20 is a plan view showing only the protrusion and the fixed electrode in FIGS. 18 and 19;

FIG. 21 is a schematic plan view schematically showing an in-liquid actuated microactuator and a mirror driven by the same according to a sixth embodiment of the present invention.

22 is a diagram schematically showing a cross section taken along line Y5-Y6 in FIG. 21 in a state where a drive signal is not supplied.

FIG. 23 is a diagram showing a state in which a drive signal is supplied.
It is a figure which shows typically the cross section along the Y5-Y6 line in 1.

FIG. 24 is a view showing a state in which a drive signal is not supplied,
It is a schematic sectional drawing which shows typically the optical switch by the 7th Embodiment of this invention.

FIG. 25 is a schematic sectional view schematically showing an optical switch according to a seventh embodiment of the present invention in a state where a drive signal is supplied.

FIG. 26 is a schematic perspective view schematically showing the optical waveguide substrate in FIGS. 24 and 25.

[Explanation of symbols]

1, 41, 51, 61, 71, 81 Submersible microactuator 2 Mirror 11 Substrate 12, 13 Leg part 14, 15 Beam part 16 Connection part 17 Movable electrode 25 Fixed electrode 42 Spacer film 43 Groove 52, 52a, 52b Curved Part 72 Protrusion 82 Through hole 90 Optical waveguide substrate 91 to 94 Optical waveguide 96 Groove 102 Refractive index adjusting liquid

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Junji Suzuki             Marunouchi 3 2-3 No. 3 shares, Chiyoda-ku, Tokyo             Ceremony company Nikon headquarters F-term (reference) 2H041 AA11 AB13 AB14 AC06 AZ05                       AZ08

Claims (11)

[Claims] 1. A fixed part and a movable part arranged in the liquid, wherein the movable part is located at a first position in contact with the fixed part and at a second position separated from the fixed part. An in-liquid actuating microactuator to be obtained, wherein a liquid surrounding the space between the contact surfaces of the movable part and the fixed part, which move away from each other when the movable part moves from the first position to the second position. An in-liquid actuating microactuator having a guide path forming structure for forming a guide path for guiding a liquid. 2. The guide path forming structure is one or more formed in at least one of a facing area of the movable portion facing the fixed portion and a facing area of the fixed portion facing the movable portion. The submersible microactuator according to claim 1, further comprising a groove. 3. The guide path forming structure includes one or more protrusions formed in at least one of a region of the movable portion facing the fixed portion and a region of the fixed portion facing the movable portion. 1. Including
The submersible microactuator described. 4. The submersible microactuator according to claim 1, wherein the guide path forming structure includes one or more through holes formed in the movable portion. 5. A fixed part and a movable part disposed in the liquid, wherein the movable part is located at a first position in contact with the fixed part and a second position separated from the fixed part. An in-liquid actuating microactuator to be obtained, wherein when the movable part is located at the first position, only a part of a region of the movable part facing the fixed part contacts the fixed part. And a submerged actuated microactuator. 6. A fixed part and a movable part arranged in the liquid, wherein the movable part is located at a first position in contact with the fixed part and at a second position separated from the fixed part. A liquid actuated microactuator to be obtained, wherein when the movable part is located at the first position, the movable part and the fixed part are in point-like or linear contact at one or more points. Characterized in-liquid actuated microactuator. 7. A fixed part and a movable part arranged in the liquid, wherein the movable part is located at a first position in contact with the fixed part and at a second position separated from the fixed part. An in-liquid actuating microactuator to be obtained, wherein the movable part has a curved part that is warped toward the fixed part side and has a spring property when not receiving a force, and the movable part moves from the second position to the first position. The submerged actuated microactuator, wherein the distal end portion of the bending portion first comes into contact with the fixed portion when moving to the position 1. 8. The submerged actuated microactuator according to claim 1, wherein the movable portion is made of a thin film. 9. The submersible microactuator according to claim 1, wherein the movable portion forms a cantilever. 10. The in-liquid actuation micro according to claim 9, wherein the fixed end of the movable portion is fixed to the fixed portion via a leg portion having a rising portion rising from the fixed portion. Actuator. 11. An optical switch comprising the submerged actuation microactuator according to claim 1 and a mirror provided on the movable portion.