JPH1172723A - Microoptical element, function element unit and their production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide microoptical elements which may be adjusted in focus. SOLUTION: An optical substrate 12 is formed of polyimide. Plural convex lenses 10 having convex surfaces 10a are two-dimensionally arrayed and formed on one surface of this substrate 12. The rear surface of the optical substrate 12 is a flat surface and on which PZT actuators 17 comprising lower layer metallic films 13, PZT thin films 14 and upper layer metallic films 15 are formed at the points corresponding to the circumferences of the convex surfaces 10 of the convex lenses 10. When voltage is impressed between the lower layer metallic films 13 and the upper layer metallic films 15, distortion arises in the PZT thin films 14. The radius of curvature of the convex lenses 10 is changed by this distortion, by which the focal length or depth of focus of the convex lenses 10 is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a micro optical element, a functional element unit, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Many optical instruments have a focusing mechanism for focusing. The focus adjustment mechanism includes a frame that movably supports the lens, and focus is performed by moving the lens along the frame. There is also a focus adjustment mechanism configured by incorporating a plurality of lenses into a frame. Since a frame and, in some cases, a plurality of lenses are required, an optical device including a focusing mechanism is necessarily required to have a certain size, and it is difficult to reduce the size.

In recent years, using micro-machining technology,
Electronic devices are being miniaturized. One of the methods is miniaturization by three-dimensional arrangement of electronic elements and the like. In this method, optical elements, electronic elements, electronic components, and the like formed on a substrate are three-dimensionally formed on the substrate using a micromanipulator. Compared with an electronic device in which electronic elements and the like are two-dimensionally arranged, a three-dimensionally arranged one can promote further miniaturization.

[0004] However, the operation of the micromanipulator is very difficult and requires time-consuming and careful operation. Furthermore, since a plurality of electronic elements cannot be formed into a three-dimensional structure at the same time, there is a disadvantage that mass productivity is lacking.

As a method of reducing the size of electronic equipment, there is a method of bonding and integrating a plurality of semiconductor wafers on which electronic elements and the like are formed. This method cannot be applied to electronic devices incorporating electronic elements.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a micro optical element having a focus adjusting mechanism.

Another object of the present invention is to provide a method capable of easily assembling a functional device three-dimensionally.

[0008] A micro optical element according to the present invention comprises an optical element having an optically functional surface and a stress generating member, wherein the stress generating member is formed around the optical element.

A lens is an example of the above optical element.
The lens includes a spherical lens, an aspherical lens, a convex lens, a concave lens, and the like, and has a spherical, aspherical, convex, and concave optical functional surface, respectively. Other examples of the above optical elements include:
There are a polarizing element, a deflecting element, and a reflector.

The stress generating member is formed of a piezoelectric material, an electrostrictive material or a magnetostrictive material.

The stress generating member may be formed at a portion corresponding to the periphery of the optically functional surface on the periphery of the optically functional surface of the optical element or on the opposite side.

Preferably, a part of the periphery of the optically functional surface is supported by a support. By deforming the support, the arrangement of the optical elements can be changed.

In one embodiment of the present invention, in the optical element, a concave portion corresponding to an optical functional surface of an optical element to be manufactured is formed on a substrate, and a polyimide is formed on the substrate so as to fill the concave portion. It is manufactured by separating at least the portion filling the recess from the substrate.

A sacrificial layer may be formed on a substrate having a concave portion, and the polyimide film may be formed on the sacrificial layer. For the sacrificial layer, a metal material such as SiO2 or Al is used. By removing only the sacrificial layer by etching, the polyimide on which the optical element is formed can be easily separated from the substrate.

When the stress generating member is a piezoelectric material, the stress generating member is distorted by applying a voltage. This distortion changes the shape of the optically functional surface of the optical element. In the case of an electrostrictive material or a magnetostrictive material, the shape of the optically functional surface is similarly changed by the action of an electric field or a magnetic field. In this manner, the focal length or the focal depth can be changed without moving the optical element (lens) or using a plurality of optical elements, and the size can be reduced. In an optical device having a set lens for focus adjustment, the number of lenses constituting the set lens can be reduced, and the size of the optical device can be further reduced.

According to the method of manufacturing a micro three-dimensional structure according to the present invention, a movable electrode supported by an elastically deformable member is provided on a substrate on which an object to be deformed is deformably supported. A fixed electrode is provided to face the movable electrode, a voltage is applied between the movable electrode and the fixed electrode, and the object is deformed by the movable electrode displaced by this.

According to the present invention, the displacement of the movable electrode caused by applying a voltage between the movable electrode supported by the elastically deformable member and the fixed electrode provided opposite to the movable electrode is controlled by the object. Use to deform things. A movable electrode and a fixed electrode may be provided with an object interposed therebetween. In this case, the movable electrode pushes the object. It is also possible to arrange the movable electrode between the object and the fixed electrode.
In this case, since the movable electrode pulls the object, the movable electrode and the object are connected by some means.

Preferably, the fixed electrode is provided on a substrate different from the substrate on which the object and the movable electrode are provided, and a voltage is applied between the two electrodes in a state where the two substrates are joined. The substrate on which the object and the movable electrode are provided is preferably a semiconductor substrate.

According to the present invention, the object can be deformed only by applying a voltage between the two electrodes, so that the operation is relatively simple. The degree of deformation of the object can be arbitrarily set by controlling the applied voltage, and the deformed object can be kept in a deformed state if necessary.

A method for producing a functional element unit according to the present invention utilizes the above-described method for producing a three-dimensional structure, in which a functional element is provided on a substrate with deformable legs, and the elastic element is provided in proximity to the legs. A movable electrode supported by a deformable member is provided, a fixed electrode is provided to face the movable electrode, and a voltage is applied between the movable electrode and the fixed electrode, whereby the movable electrode is displaced. The object is deformed.

The functional elements include optical elements such as light-emitting elements, light-receiving elements, and lenses, preferably micro-optical elements, micro-electronic elements, and other elements used in optical and electronic equipment.

According to the present invention, the functional element can be brought to an arbitrary posture only by applying a voltage between the movable electrode and the fixed electrode, and batch processing can be performed. Functional element units (for example, micro optical units) can be mass-produced at a time. In addition, since a technique for bonding semiconductor wafers is not used, there is no need to perform high-temperature processing. In the functional element unit manufactured according to the present invention, since the functional elements are arranged three-dimensionally above, below, or inside the substrate (when there is a hole), the size of the entire unit can be reduced.

That is, in the functional element unit according to the present invention, the functional element is supported on the substrate by the deformable leg, the leg is deformed, and a movable electrode for deforming the leg is provided on the leg. They are provided close to each other.

Preferably, the legs are formed of a thermosetting material, and after the legs are deformed, the legs are heated and cured.

By hardening the legs in a deformed state, the displaced posture of the functional element can be maintained.
Preferably, polysilicon is used for the legs. Polysilicon has the property of being cured when heated by being energized.

[0026]

【Example】

(1) Micro optical element FIG. 1 is a cross-sectional view showing a part of an optical substrate having a lens array manufactured using polyimide.

The optical substrate 12 is a plate-like polyimide substrate, and a plurality of convex lenses 10 are formed on one surface thereof and are two-dimensionally arranged. The convex surface 10a of the convex lens 10 is a smooth curved surface. A lens array is formed by the plurality of convex lenses 10. By dividing the optical substrate 12 by, for example, dicing, a single convex lens 10 can be formed. The convex lens 10 is used to collect the diverging or collimated light or to collimate the diverging light.

FIG. 2 shows a manufacturing process of the optical substrate 12 shown in FIG.

A substrate 20 is prepared (FIG. 2A). Silicon is used as the material of the substrate 20. Silicon can be finely processed by micromachining technology.

A concave portion 20 having a shape corresponding to the shape of the convex surface 10a of the convex lens 10 to be formed is formed on one surface of the silicon substrate 20.
a is formed by isotropic etching (FIG. 2B)
). A plurality of two-dimensionally arranged recesses 20a are formed on the silicon substrate 20. By forming a plurality of concave portions 20a on the silicon substrate 20, a plurality of convex lenses 10 can be manufactured at one time.

An SiO2 sacrificial layer 11 is formed on a silicon substrate 20 by thermal oxidation or deposition (FIG. 2C). Si
On the surface of the O2 sacrificial layer 11, a concave portion 11a having a smooth curved surface is formed at a position corresponding to the concave portion 20a. SiO2 sacrificial layer
Reference numeral 11 is used to facilitate separation of the optical substrate 12 to be manufactured from the silicon substrate 20. A metal such as Al may be used as the sacrificial layer.

A polyimide 12 is applied from above the SiO 2 sacrificial layer 11 so as to fill the recesses 11a and is cured (FIG. 2D).
).

After the polyimide 12 is cured, the SiO 2 sacrificial layer 11 is removed by etching, and the optical substrate 12 is separated from the silicon substrate 20. The portion buried in the concave portion 11a becomes the convex lens 10, and the optical substrate 12 on which the plurality of convex lenses 10 are two-dimensionally arranged is completed (FIG. 1).

In FIG. 2B, when forming the recess 20a, the performance (radius of curvature, focal length,
Focal depth, etc.).

FIG. 3 is a sectional view showing a part of an optical substrate having another structure manufactured using polyimide.

In the optical substrate 12A, a concave surface 10b is formed on the opposite side to the convex surface 10a of the convex lens 10A with a smooth curved surface.

The concave surface 10b of the convex lens 10A is formed by pressing a stamper having a convex mold surface corresponding to the concave surface 10b before the polyimide is cured, or by removing the cured polyimide by etching.

Convex lens 10 and convex surface 10 of convex lens 10A
It goes without saying that the shape of a and the concave surface 10b of the convex lens 10A may have other shapes.

FIGS. 4A and 4B show the structure of an optical substrate provided with a PZT (lead zirconate titanate) actuator. FIG. 4A is a plan view thereof, and FIG. 4B is a sectional view taken along line IV-IV of FIG. It is sectional drawing. In FIG. 4 (B), the thickness of each component member of the PZT actuator is exaggerated from the actual thickness for the convenience of drawing and for easy understanding. This is the same in other sectional views described later. The same components as those shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

The PZT actuator 17 includes a lower metal film 13, a PZT (lead zirconate titanate) thin film 14, and an upper metal film on the flat surface (the surface opposite to the surface on which the convex surface 10a is formed) of the optical substrate 12. 15 are stacked in this order. The PZT actuator 17 has an annular portion formed in an annular shape and two linear portions formed in a linear shape. The annular portion is formed on the flat surface of the optical substrate 12 at a portion corresponding to the periphery of the convex surface 10a of the convex lens 10. A portion of the annular portion is cut off, and straight portions extend outward from both ends.

The two linear portions of the PZT actuator 17 are used as drive terminals (external connection terminals) of the PZT actuator 17. One of the two linear portions has a lower metal film 13, a PZT thin film 14, and an upper metal film 15.
(The upper metal film 15 in the linear portion is shown as a terminal 15a). In the other linear portion, only the lower metal film 13 (the lower metal film 13 in the linear portion is shown as a terminal 13a) is formed. When a voltage is applied between the lower metal film 13 and the upper metal film 15 through these terminals 13a and 15a, a PZT thin film sandwiched between these metal films 13 and 15 is applied.
Strain (stress) occurs inside 14. As a result, the convex lens 10 is distorted, and its radius of curvature changes. Convex lens 10
When the radius of curvature changes, the focal length or the focal depth of the convex lens 10 changes.

By controlling the distortion generated in the PZT thin film 14 (by controlling the voltage applied to the PZT actuator 17), the focal length of the convex lens 10 or the focal length of the convex lens 10 can be reduced without using a plurality of lenses or moving the lenses themselves. The depth of focus can be adjusted. In an optical device having a set lens for focus adjustment, the number of lenses constituting the set lens can be reduced, so that the size of the optical device can be reduced. The lens performance (radius of curvature,
Even if the focal length, depth of focus, etc.) differ from the designed value due to the aging of the polyimide or due to heating during mounting, fine adjustments can be made after mounting the lens on the optical device. . Therefore, in actual use of the optical device, the same desired lens performance as that designed can be obtained. Although FIG. 4 shows a lens array, it goes without saying that the above applies to a single lens.

FIG. 5 shows a structure in which a supporting portion is attached to a convex lens having the PZT actuator shown in FIG. 4, (A) is a plan view thereof, and (B) is a cross section taken along line VV of (A). FIG. These figures show a state in which three single lenses are arranged, but this is because the description of the manufacturing process shows that three lenses are manufactured at the same time. FIGS. 6 and 7 show steps of manufacturing a convex lens to which the support shown in FIG. 5 is attached. In FIG. 6, (A1), (B1), (C1) and (D1) shown on the left are plan views of the optical substrate, and (A2), (B2), (C2) and
(D2) is a cross-sectional view of the corresponding plan view. Similarly,
In FIG. 7, (A1) and (B1) shown on the left are plan views of the optical substrate, and (A2) and (B2) shown on the right are cross-sectional views of the corresponding plan views.

As in the steps shown in FIGS. 2A to 2C,
A concave portion 20a having a shape corresponding to the convex surface of a convex lens to be produced is formed on a silicon substrate 20, and a SiO2 sacrificial layer 11 having a concave portion 11a is formed thereon (FIGS. 6 (A1) and 6 (A2)). Subsequently, polysilicon 16A is deposited so as to fill the concave portions 11a of the SiO2 sacrificial layer 11 (FIGS. 6 (B1) and 6 (B2)). Thereafter, the polysilicon support portion 16 consisting of the annular portion which is partially missing and the linear portion extending outward from both ends of the annular portion is left, and all the polysilicon 16A in the other region is removed (FIG. 6 (C1)). ), (C2)). The annular portion of the support portion 16 has a concave portion 20a,
It is located at a position corresponding to the periphery of 11a and supports the convex lens 10 to be formed next.

A polyimide 12 is applied so as to fill the concave portion 11a and cover the SiO 2 sacrificial layer 11 and the support portion 16 and is cured (FIGS. 6 (D1) and 6 (D2)). After curing of polyimide 12, concave
Remove all the polyimide 12 inside 11a, the inside of the annular portion of the support portion 16 and its upper surface (excluding the outer peripheral edge), and the polyimide on the other portion except for the polyimide on the linear portion of the support portion 16 (FIG. 7 (A1), (A2)). The remaining polyimide becomes the convex lens 10.

The lower metal film 13 is formed on the flat surface of the convex lens 10.
Then, a PZT actuator 17 composed of the PZT thin film 14 and the upper metal film 15 is formed (FIGS. 7B1 and 7B2).

The SiO 2 sacrificial layer 11 is removed by etching. The convex lens 10 having the polyimide portion embedded in the concave portion 11a of the SiO2 sacrificial layer 11 as a lens portion and the periphery of which is sandwiched by the annular portion of the support portion 16 is completed. PZT is provided on the support 16 via a polyimide layer.
The actuator 17 is provided (FIG. 5).

Unless the SiO 2 sacrificial layer 11 is removed, the plurality of convex lenses 10 are kept arranged on the silicon substrate 20 to form a lens array. This configuration is shown in FIG. Only the portion of the silicon substrate 20 corresponding to the convex surface 10a of the convex lens 10 is etched away from the lower surface thereof. The hole removed by etching is indicated by reference numeral 20A. Light passes through this hole 20A.
The convex surface 10a of the convex lens 10 is protected by the silicon substrate 20 and the SiO2 sacrificial layer 11, and handling during transportation and the like is facilitated.

(2) Method for Producing a Micro Three-Dimensional Structure Prior to the description of the micro optical unit (micro optical three dimensional structure) using the above-described micro optical element, a method for preparing a micro three dimensional structure will be described.

FIG. 9 is a perspective view showing a micro three-dimensional structure and an auxiliary structure used in a step of erecting a functional element in the micro three-dimensional structure. FIG. 10 is a sectional view taken along line XX in FIG. Here, the micro three-dimensional structure refers to a structure in which a functional element having some physical function represented by a lens, a light emitting element, a light receiving element, or the like is provided on a substrate by a leg. The functional element and the legs are initially in a lying position, but are raised using the auxiliary structure as described below. In this specification, both the functional element in a lying posture and the functional device in a standing posture are referred to as a micro three-dimensional structure for convenience.

In the micro three-dimensional structure 30 shown in FIGS. 9 and 10, the functional element 44 and the leg 43 are in a lying posture. The micro three-dimensional structure 30 includes a conductive silicon substrate 32.
A hole 32A is formed in the center of the silicon substrate 32 in the vertical direction. The portion of the silicon substrate 32 around the hole 32A is called a frame portion 33. A movable electrode 34 is provided at the center of the upper portion of the hole 32A. The movable electrode 34 is integrally connected to the upper portion of the frame portion 33 by a bar 35 extending in one direction from one side. The frame 33, the movable electrode 34, and the bar 35 can be formed by etching the silicon substrate 32 with high precision.

The bar 35 is formed quite thin. bar
The movable electrode 34 supported on the upper part of the frame part 33 by 35
Is also made thin. The thin bar 35 can be elastically deformed (twisted as will be described later).

On the frame portion 33 of the silicon substrate 32,
Two substantially square insulating films 41 are formed at an interval, and external connection terminals 42 having the same shape as the insulating film 41 are formed on the two insulating films 41, respectively. External connection terminal 42
And the leg 43 are integrally formed, and the leg 43 is an external connection terminal.
It extends from 42 to above the tip of the movable electrode 34 and is connected to each other there. There is a slight gap between the leg 43 and the movable electrode 34. The external connection terminal 42 and the leg 43 are made of polysilicon (electrical resistor), and a current flows through the leg 43 through the external connection terminal 42 as described later.
The functional element 44 has a leg at a position almost directly above the movable electrode 34.
It is attached to 43 tips.

The auxiliary structure 31 is formed of an insulating material such as glass, and has a size corresponding to the size of the silicon substrate 32. At four corners of the auxiliary structure 31 on the side facing the silicon substrate 32, a rectangular columnar support portion 37 is formed. The portion of the auxiliary structure 31 excluding the support portion 37 is made thin.

A fixed electrode 46 having substantially the same size and shape as the movable electrode 34 is provided at a position facing the movable electrode 34 in the thinly formed portion of the auxiliary structure 31. A terminal 46 a extends from a part of the fixed electrode 46 to an end of the auxiliary structure 31. The terminal 46a is connected to a fixed electrode as described below.
Used to apply voltage to 46.

FIGS. 11 (A), 11 (B) and 11 (C) show a process for erecting a functional element in a micro three-dimensional structure.

After the lower surface of the support portion 37 of the auxiliary structure 31 is overlaid and fixed on the frame portion 33 of the silicon substrate 32, the fixed electrode 46 and the movable electrode are passed through the terminal 46a and the silicon substrate 32.
Apply voltage between 34 and. Then, an electrostatic force (electrostatic attraction) is generated between the fixed electrode 46 and the movable electrode 34, and the tip of the movable electrode 34 (the side opposite to the one side supported by the bar 35) is fixed. Attracted to. Movable electrode 34
Is supported on one side by a bar 35 that can be elastically deformed (twisted), so that the tip of the movable electrode 34 stands up.
11 (A)).

Since the distal end of the leg 43 is located above the movable electrode 34, when the distal end of the movable electrode 34 is drawn toward the fixed electrode 46, the leg 43 is pushed upward. The leg 43 formed of highly elastic polysilicon rises while being smooth. The functional element 44 provided at the tip of the leg 43 rises when the leg 43 goes up (FIG. 11B).

In a state where a voltage is applied between the fixed electrode 46 and the movable electrode 34, a current flows from the two external connection terminals 42 on the frame 33 to the leg 43. The polysilicon constituting the leg 43 is heated and hardened by energization. As the leg 43 hardens, the functional element 44 is fixed in an upright posture. When the application of the voltage to the fixed electrode 46 and the movable electrode 34 is stopped, the movable electrode 34 returns to the original position (FIG. 11 (C)).

FIG. 12 is a perspective view showing a micro three-dimensional structure having another structure and an auxiliary structure. FIG. 13 shows XIII-XIII of FIG.
It is a sectional view taken along a line. This micro three-dimensional structure 30A is
As compared with the micro three-dimensional structure 30 shown in FIGS. 10 and 11, the adhesive layer 47 having a hole 47A between the movable electrode 34 and the leg 43 is formed.
Is provided, and a hole 34A is formed in the movable electrode 34. Other structures are the same as those shown in FIGS. 10 and 11. The auxiliary structure 31 is disposed below the micro three-dimensional structure 30A.

In the micro three-dimensional structure 30A, the movable electrode 34
The leg 43 is adhered to the movable electrode 34 by an adhesive layer 47 provided between the movable electrode 34 and the leg 43. The hole 34A formed in the movable electrode 34 is located between the two legs of the leg 43. The hole 47A of the adhesive layer 47 is provided at a position corresponding to the hole 34A.

The auxiliary structure 31 is formed by fixing the fixed electrode 46 to the hole 32A.
The lower surface of the support portion 37 of the auxiliary structure 31 is overlapped and fixed to the lower surface of the frame portion 33 of the silicon substrate 32 so as to be located substantially below the center of the silicon substrate 32.
A voltage is applied between the fixed electrode 46 and the movable electrode 34 through the terminal 46a and the silicon substrate 32. The movable electrode 34 is directed downward by an electrostatic force (electrostatic attraction) acting between the fixed electrode 46 and the movable electrode 34. Since the leg 43 is bonded to the movable electrode 34 by the adhesive layer 47, the leg 43 also bends downward. The functional element 44 attached to the leg 43 is a silicon substrate
Enter inside 32 hole 32A.

In a state where a voltage is applied between the fixed electrode 46 and the movable electrode 34, a current is applied to the leg 43 to harden the polysilicon constituting the leg 43. Finally, fixed electrode 46 and movable electrode
The application of the voltage to 34 is stopped, and the movable electrode 34 is returned to the original position. The leg 43 and the movable part 34 maintain the attitude stored in the hole 32A.

As will be described later in detail, when the functional element 44 is a light emitting element, light is emitted through the space between the holes 47A and 31A and the leg 43. When the functional element 44 is a light receiving element, the hole 47A,
Light that has passed between 31A and the leg 43 can be received.

(3) Micro Optical Unit A micro optical unit manufactured by using the above-described method for manufacturing a micro three-dimensional structure will be described.

FIG. 14 is a cross-sectional view of a micro optical unit (micro optical three-dimensional structure) in which a convex lens on which a PZT actuator is formed is provided on a substrate by a leg.
Since the structure of the micro optical unit 60 shown in FIG. 14 will be clarified by describing the manufacturing process, the manufacturing process will be described with reference to FIGS. Figure 15 to Figure
In FIG. 17, (A1), (B1) and (C1) shown on the left side are plan views of the manufacturing process of the micro optical unit. Shown on the right
(A2), (B2) and (C2) are cross-sectional views of corresponding plan views. Similarly, (A1) shown on the left side in FIG. 18 is a plan view of the manufacturing process of the micro optical unit, and shown on the right side.
(A2) is a sectional view taken along the line XVIII-XVIII of (A1).

A silicon substrate 32 is prepared, and recesses 32a and 32b are formed at two places on the upper surface by etching. Recess
32a is formed so as to leave a portion to become the movable electrode 34 on the upper surface of the silicon substrate 32, and to leave a portion to become the bar 35 by the concave portions 32a and 32b (FIGS. 15A1 and 15B1). ).

In the center of the upper surface of the silicon substrate 32,
a and an SiO ₂ sacrificial layer so as to completely cover the
51 is formed by thermal oxidation or deposition. The peripheral portions of the concave portions 32a and 32b are filled with a SiO ₂ sacrificial layer,
On the surface of the SiO ₂ sacrificial layer 51, a recess 51a remains at a position corresponding to the center of the recess 32a, and a recess 51b remains at a position corresponding to the center of the recess 32b (FIGS. 15 (B1) and (B2)).

Further, on the SiO ₂ sacrificial layer 51, a concave portion 51a,
Polysilicon 52 is deposited to fill 51b (FIG. 15 (C
1), (C2)).

The polysilicon 52 is isotropically etched at a position corresponding to the concave portion 51a so as to form a concave portion 52a having a smooth curved surface (FIG. 16 (A1), (A)).
2)).

An SiO ₂ sacrificial layer 53 is formed so as to cover the polysilicon 52 (FIGS. 16 (B1) and (B2)). SiO ₂ sacrificial layer 53
Covers the peripheral side surfaces of the SiO ₂ sacrificial layer 51 and the polysilicon 52.
On the surface of the SiO ₂ sacrificial layer 53, a concave portion 53a having a smooth curved surface remains at a position corresponding to the concave portion 52a. The convex lens to be manufactured has a convex surface having a shape corresponding to the concave portion 53a.

The silicon substrate 32 is placed on the SiO ₂ sacrificial layer 53.
A polysilicon support layer 54 is formed over the substrate (FIG. 16
(C1), (C2)). The polysilicon support layer 54 is formed by patterning and depositing polysilicon, and has an annular portion 54A surrounding the recess 53a and partially missing, and an annular portion 54A.
And leg portions 54B extending from both ends. Legs
54B extends over the substrate 32. The portion provided on the substrate 32 is indicated by 54C. Portion 54C is an insulating layer on substrate 32
It is provided through 58. The polysilicon support layer 54
It is used to support the periphery of the convex lens to be manufactured and to maintain the posture of the convex lens (heated and hardened by passing an electric current). The portion 54C formed on the substrate 32 is also used as a terminal used to pass a current.

The recess 53a is filled and the polysilicon support layer 54
A polyimide 55 is formed by patterning and deposition along the inside (FIG. 17 (A1), (A2)). Polyimide 55
Is formed on the substrate 32, extending further outward from the polysilicon support layer. The portion of the polyimide 55 filling the concave portion 53a becomes the convex lens 55A. The polyimide portion formed on the leg portion 54B of the polysilicon support layer 54 is
In B, the polyimide portion formed on the substrate 32 is indicated by 55C.

The outer periphery of the convex lens 55A and the polyimide portion 55
A PZT actuator 17 composed of a lower metal film 13, a PZT thin film 14, and an upper metal film 15 is formed on B, 55C (FIG.
17 (B1), (B2)). 4, 5 and 8, only the lower metal film 13 is laminated on one of the two polyimide portions 55B and 55C.

After the above steps, two etchings are performed. The first etching is for shaving the central portion of the silicon substrate 32 from the lower surface to a position below the SiO ₂ sacrificial layer 51 (FIGS. 17 (C1), (C2)). A concave portion 32B is formed in the silicon substrate 32. The recess 32B is formed in a rectangular portion including the recesses 32a and 32b.

The Si exposed by the first etching
The _second etching is further performed from the lower surfaces of the O ₂ sacrificial layer 51, the movable electrode 34, and the bar 35 to remove the SiO ₂ sacrificial layer 51, the polysilicon 52, and the SiO ₂ sacrificial layer 53 (FIG. 18A
1), (A2)). Holes communicating vertically in the silicon substrate 32
32A is available. The convex lens 55A is supported by the substrate 32 above the hole 32A by the polysilicon support layer 54, and the micro optical unit (micro optical three-dimensional structure) 60 in which the PZT actuator 17 is provided on the polysilicon support layer 54 is completed.

As shown in FIG. 19, the glass substrate 31 provided with the fixed electrode 46 is placed on the silicon substrate 32, and the lower surface of the support portion 37 of the glass substrate 31 is placed on the frame portion of the silicon substrate 32.
Anodized and superimposed on 33.

As shown in FIG. 20, the fixed electrode 46 and the movable electrode
When a voltage is applied to the silicon substrate 32, the tip of the movable electrode 34 is attracted to the fixed electrode 46, and the polysilicon support layer 54 and the convex lens 55A stand on the silicon substrate 32. In this state, when a current flows from the polysilicon portion 54C on the substrate 32 to the polysilicon support layer 54, the polysilicon support layer 54 is heated and hardened. The convex lens 55A is fixed on the silicon substrate 32 by the polysilicon support layer 54 in an upright posture.

Application Example FIG. 21 shows an optical switching unit in which a micro optical unit having a convex lens having a PZT actuator shown in FIG. 14 and a micro optical unit having a light receiving element are integrally formed using the same substrate. It is sectional drawing. Fig. 14
The same reference numerals are given to the same components as those described in (1), and redundant description is avoided.

The optical switching unit 80 includes a substrate 32, on which two holes 32A and 32C are formed. Above one hole 32A, a convex lens 55A supported by a polysilicon support layer 54 is provided in an upright posture. That is, the polysilicon support layer 54 is
When a current is applied in a state where a voltage is applied between A and the fixed electrode 46A, it is raised and fixed in its posture.

On the other hand, a movable electrode 34B is formed above the hole 32C.
It is provided in. Above the movable electrode 34B, the auxiliary structure 31 is provided with a fixed electrode 46B. Light receiving element
The standing and prone position of 71 is controlled by the voltage applied between the movable electrode 34B and the fixed electrode 46B.

When a voltage is applied between the fixed electrode 46B and the movable electrode 34B, the movable electrode 34B is attracted to the fixed electrode 46B, and the light receiving element 71 stands on the silicon substrate 32. The light emitted from the light emitting element (not shown) is condensed or collimated by the convex lens 55A and enters the light receiving element 71.
At this time, the optical switch is on.

When the application of the voltage between the fixed electrode 46B and the movable electrode 34B is stopped, the movable electrode 34B returns to the original position, and the light receiving element 71 returns to the lying posture. The light from the convex lens 55A does not enter the light receiving element 71. The light switch turns off.

FIG. 22 is a sectional view showing another example of the optical switching unit. The same components as those shown in FIG. 21 are denoted by the same reference numerals, and redundant description will be omitted.

In the optical switching unit 90, the auxiliary structure 31 is disposed below the silicon substrate 32.
The convex lens 55A is fixed in an inverted state by applying a voltage between the movable electrode 34A and the fixed electrode 46A and energizing the polyimide support layer 44. The position of the light receiving element 71 is controlled according to the application and stoppage of the voltage between the movable electrode 34B and the fixed electrode 46B.

Light passing holes 32D and 32E communicating the hole 32A with the outside and the hole 32A with the hole 32C are formed in the portion of the silicon substrate 32 through which light passes. Light emitting element (not shown)
The light emitted from the lens passes through the light passage hole 32B and is projected to the convex lens 55.
A is incident on A. The light collected or collimated by the convex lens 55A enters the light receiving element 71 through the light passage hole 32E. The optical switching controls the position of the light receiving element 71 (movable electrode 71) as in the optical switching unit 80 shown in FIG.
Controls the voltage applied between 34B and fixed electrode 46B)
Achieved by:

Functional elements such as a convex lens, a light emitting element, and a light receiving element are vertically erected on a silicon substrate 32.
Alternatively, it goes without saying that it can be fixed not only vertically in a hole formed in the silicon substrate 32 but also in a posture oriented at an arbitrary angle. By adjusting the magnitude of the voltage applied between the fixed electrode and the movable electrode or the timing at which a current flows through the polysilicon, the functional element can be fixed in a posture facing an arbitrary angle. If a piezoresistive element is formed on the legs (polysilicon 54, polyimide 55 or PZT actuator 17), the angle of the functional element rising or the silicon substrate 32 may be changed based on the change in the resistance value output from the piezoresistive element. The angle stored in the hole can be detected. The posture of the functional element can be controlled based on the change in the resistance value of the piezoresistive element. The piezoresistive element may be formed on the bar 35. By detecting the torsion of the bar 35, the angle of the functional element standing or the angle stored in the hole of the silicon substrate 32 is detected.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a part of an optical substrate manufactured using polyimide.

2 (A), (B), (C) and (D) are cross-sectional views showing steps of manufacturing the optical substrate shown in FIG.

FIG. 3 is a cross-sectional view showing an optical substrate having another structure manufactured using polyimide.

4A is a plan view showing the structure of an optical substrate having a PZT actuator, and FIG. 4B is a sectional view taken along line IV-IV of FIG.

5A is a plan view showing a structure in which a supporting portion is attached to a convex lens provided with a PZT actuator, and FIG. 5B is a plan view of FIG.
It is sectional drawing which follows a VV line.

FIGS. 6 (A1), (B1), (C1) and (D1) are plan views showing steps of manufacturing the convex lens shown in FIG. 5, and FIGS.
(2) and (D2) are (A1), (B1), (C1) and (D1), respectively.
It is a sectional view taken along the lines VIA-VIA, VIB-VIB, VIC-VIC and VID-VID.

FIGS. 7 (A1) and (B1) are plan views showing steps of manufacturing the convex lens shown in FIG. 5, and FIGS.
It is sectional drawing along the VIIA-VIIA line and VIIB-VIIB line of (1) and (B1).

8A is a plan view of a lens array having a structure in which a supporting portion is attached to a convex lens having a PZT actuator, and FIG. 8B is a sectional view taken along line VIII-VIII of FIG. 8A.

FIG. 9 is a perspective view showing a micro three-dimensional structure and an auxiliary structure used in a step of erecting a functional element.

FIG. 10 is a sectional view taken along line XX of FIG. 9;

FIGS. 11A, 11B and 11C are cross-sectional views showing steps of erecting a functional element in a micro three-dimensional structure.

FIG. 12 is a perspective view showing a micro three-dimensional structure having another configuration and an auxiliary structure used in a step of erecting a functional element.

FIG. 13 is a sectional view taken along line XIII-XIII of FIG. 12;

FIG. 14 is a sectional view of a micro optical unit including a convex lens on which a PZT actuator is formed.

FIGS. 15 (A1), (B1) and (C1) are plan views showing steps of manufacturing a micro optical unit including a convex lens on which a PZT actuator is formed, and FIGS. 15 (A2), (B2) and (C2).
Are the XVA-XVA lines and (XVB-XV) of (A1), (B1) and (C1), respectively.
It is a sectional view taken along line B and XVC-XVC.

FIGS. 16 (A), (B1), and (C1) are plan views showing steps of fabricating a micro optical unit including a convex lens on which a PZT actuator is formed, and FIGS. 16 (A), (B2), and (C).
2) are the XVIA-XVIA lines and XV of (A1), (B1) and (C1), respectively.
It is a sectional view taken along line IB-XBIB and line XVIC-XVIC.

FIGS. 17 (A), (B1) and (C1) are plan views showing steps of manufacturing a micro optical unit including a convex lens on which a PZT actuator is formed, and FIGS. (A2), (B2) and (C2)
Are the XVIIA-XVIIA lines and (XV) of (A1), (B1) and (C1), respectively.
It is sectional drawing along the IIB-XBIIB line and the XVIIC-XVIIC line.

FIG. 18 (A1) is a plan view showing a step of manufacturing a micro optical unit including a convex lens on which a PZT actuator is formed, and FIG. 18 (A2) is a sectional view taken along line XVIII-XVIII of (A1).

FIG. 19 is a cross-sectional view illustrating a step of manufacturing a micro optical unit including a convex lens on which a PZT actuator is formed.

FIG. 20 is a cross-sectional view showing a step of manufacturing a micro optical unit including a convex lens on which a PZT actuator is formed.

FIG. 21 is a sectional view of a micro optical unit constituting a switching mechanism.

FIG. 22 is a cross-sectional view showing another example of the micro optical unit constituting the switching mechanism.

[Explanation of symbols]

10,10A lens 11,51,53 SiO ₂ sacrificial layer 12,12A optical substrate 13 lower metal film 14 PZT thin film 15 upper-layer metallic film 30 micro three-dimensional structure 31 auxiliary structure 32 silicon substrate 33 frame portion 34,34A movable electrode 35 Bar 41 Insulation film 42 External connection terminal 43 Leg 46 Fixed electrode

Claims (6)

[Claims] 1. A micro-optical element comprising: an optical element having an optically functional surface; and a stress generating member, wherein the stress generating member is formed around the optical element. 2. A concave portion corresponding to an optical function surface of an optical element to be produced is formed on a substrate, polyimide is formed on the substrate so as to fill the concave portion, and at least a portion of the polyimide which fills the concave portion. A method for producing an optical element, wherein the optical element is separated from the substrate. 3. A substrate on which an object to be deformed is deformably supported is provided with a movable electrode supported by an elastically deformable member in proximity to the object, and fixed to face the movable electrode. A method for producing a micro three-dimensional structure, comprising: providing an electrode; applying a voltage between the movable electrode and the fixed electrode; and deforming the object by the movable electrode displaced by the electrode. 4. A functional element is provided on a substrate by a deformable leg, a movable electrode supported by an elastically deformable member is provided near the leg, and a fixed electrode is provided to face the movable electrode. A method for producing a functional element unit, wherein a voltage is applied between the movable electrode and the fixed electrode, and the leg is deformed by the movable electrode displaced by the voltage. 5. The method according to claim 4, wherein the leg is formed of a thermosetting material, and after the leg is deformed, the leg is heated and cured. 6. A functional element is supported on a substrate by a deformable leg, the leg is deformed, and a movable electrode for deforming the leg is provided near the leg. Functional element unit.