JP2004219839A - Three-dimensional structure and its manufacturing method, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a three-dimensional structure usable as a comb-tooth actuator which has a simple constitution, can easily be manufactured, has an excellent mechanical strength, and has high electric reliability. <P>SOLUTION: At the flat part of a substrate 10, a mirror 20 and a 1st electrode 31 which is coupled with it are formed. Parts of the substrate 10 are slope parts 12A and 12B bent along a bent part 11 which is incompletely separated, and a 2nd electrode 32 is formed at the slope parts 12A and 12B. The 2nd electrode 32 has a gap 33 perpendicular to the flat part of the substrate 10 with respect to the 1st electrode 31. The substrate 10 is preferably an SOI (silicon on insulator) substrate having an oxide film and a semiconductor thin film formed on the surface of a holding substrate. The bent part 11 preferably has constitution such that a V-shaped groove is formed in the holding substrate by anisotropic etching and at least one of the oxide film and semiconductor film is left. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a three-dimensional structure used in the field of MEMS (Micro Electro Mechanical Systems), a method of manufacturing the same, and an electronic device using the same.
[0002]
[Prior art]
As an example of a three-dimensional structure using MEMS, there is a micromirror (scanning mirror) that deflects a laser beam in electronic devices such as a laser scanner and a barcode reader. The micromirror is manufactured by micromachining of a silicon (Si) substrate. For example, a micromirror using a planar portion of a silicon substrate and a torsion hinge (torsion bar) supporting the micromirror are used. Are formed by anisotropic etching.
[0003]
As an electrode structure for driving such a micromirror, a so-called vertical comb-tooth actuator in which two comb-like electrodes are arranged with a gap in a direction perpendicular to the direction in which the comb teeth extend is known. (For example, see Patent Document 1). FIG. 13 shows an example of a conventional vertical comb actuator. This actuator is composed of a pair of comb-shaped electrodes 112 and 113, and a DC power supply 114 is connected to these electrodes 112 and 113. One electrode 112 is fixed on the silicon substrate 111 side, and the other electrode 113 is connected to a movable body such as a micromirror (not shown). The electrodes 112 and 113 are provided with a gap 115 in a direction perpendicular to the surface of the silicon substrate 111. When a predetermined voltage is applied between the electrodes 112 and 113 by the DC power supply 114, a rotational torque is applied to the support shaft 113 </ b> A of the electrode 113 by the electrostatic force acting between the electrodes 112 and 113, and the electrode 113 is moved in the direction of the arrow 116 ( The micromirror rotates in the same direction as it is displaced clockwise.
[0004]
FIG. 14 shows another configuration of the vertical comb actuator, in which the electrodes 113 are arranged obliquely. In such a configuration example, when a voltage is applied between the electrodes 112 and 113, the electrode 113 is displaced in the direction of the arrow 117, and the rotation angle is larger than in the configuration of FIG. 13 in which the electrodes 112 and 113 are provided in parallel. be able to.
[0005]
As a method of forming an angle on the comb teeth as described above, conventionally, for example, as shown in FIG. 15, a method using the surface tension of a resist is known (for example, Non-Patent Document 1, Non-Patent Document 2 and Non-Patent Document 3). That is, in the example of FIG. 14, the comb teeth 113B of the electrode 113 are cut off from the silicon substrate 111, and a resist 118 is applied to the cut off portion and patterned. Thereafter, when the temperature of the resist 118 is raised to a liquid state, the comb teeth 113B are pulled by the surface tension of the resist 118, and the comb teeth 113B can be angled. The inclination angle of the comb teeth 113B is determined uniquely when a stopper is provided in the structural pattern and the stopper hits the stopper.
[0006]
[Patent Document 1]
JP 2000-147419 A
[Non-patent document 1]
R. R. A. R. Sims (R.R.A.Syms.), Two people, Improving field, accuracy and complexity in surface tension self-assembled MOEMS, "Sensors and Activision, August 2008," Vol.3, No.5, p273-283
[Non-patent document 2]
R. R. A. Sims (RRA Sims), Self-assembled 3-D silicone-scanners with self-assembled electrostatic drives, "IEEE Photonics Technology, IEEE, November 11, 2000, November 11, 2000, November 11, 2000. -1521
[Non-Patent Document 3]
Pamela R. Patterson (Pamela R. Patterson), 5 members, A scanning micromirror with angular comb drive actuation, "The Fifteenth IEEE, International, International, Microelectronics, 200, International Conference on Microphone, International Conference on Microelectronics.
[0007]
[Problems to be solved by the invention]
As described above, any of the conventional vertical comb actuators can drive a micromirror or the like by applying a voltage, but has the following problems. That is, in the actuator having the configuration in which the electrodes 112 and 113 shown in FIG. 13 are provided in parallel with each other, for example, the electrodes 112 and 113 are formed on two substrates, respectively, and are adhered to each other. And the manufacturing process was complicated.
[0008]
In the actuator having a structure in which the comb teeth 113B are angled using the surface tension of the resist 118 shown in FIG. 15, the comb teeth 113B are completely separated from the substrate 111 and are supported only by the resist 118. Therefore, there was a problem in the strength of the comb teeth 113B. Therefore, if an excessive torque is applied to the resist 118, the comb portion 113B may be broken, and it cannot be applied to a micromirror requiring a large torque. Further, since the resist 118 has fluidity at about 150 ° C., there is a problem that it cannot be used at a high temperature.
[0009]
Further, in the manufacturing process, the resist 118 may enter the gap between the separated comb tooth portion 113B and the substrate 111, but it is difficult to completely remove the resist 118 that has entered the gap. Was. In order to solve this problem, for example, it has been proposed to bury an oxide film in a gap between the comb portion 113B and the substrate 111. However, this has a problem that the manufacturing process is further complicated (for example, Non-Patent Document 3).
[0010]
In addition, the accuracy of the inclination angle of the comb tooth portion 113B is about 0.5 degrees despite its advanced structure. Furthermore, the angle of inclination of the comb teeth 113B is determined at the time of designing the mask, and cannot be changed later. In addition, since the comb teeth portion 113B also serves as an electrode, it is necessary to form a wiring pattern on the resist 118 by sputtering of a conductive material. However, the wiring pattern on the resist 118 has electrical reliability. There is a problem of low.
[0011]
The present invention has been made in view of the above problems, and has as its object to provide a three-dimensional structure which can be easily manufactured, has excellent mechanical strength, and can be used as a highly reliable electric comb actuator. And a method for manufacturing the same, and an electronic device using the same.
[0012]
[Means for Solving the Problems]
The three-dimensional structure according to the present invention uses a substrate having a flat portion, and is formed by connecting a displaceable main body formed on the flat portion of the substrate to the main body on the flat portion of the substrate. A first electrode, a straight bent portion formed on the substrate that is not completely separated, an inclined portion formed by bending a part of the substrate along the bent portion, And a second electrode that is formed so as to have a predetermined interval between the first electrode and the first electrode and that forms a driving unit together with the first electrode.
[0013]
The method for manufacturing a three-dimensional structure according to the present invention is for manufacturing a three-dimensional structure using a substrate having a flat portion, wherein the flat portion of the substrate is connected to a displaceable main body and a main body. Forming a first electrode and a second electrode that is paired with the first electrode and is not connected to the main body; and selectively removing the substrate to form a straight fold that is not completely separated. Forming a slanted portion by bending a part of the substrate along the bent portion, thereby providing a predetermined interval between the second electrode and the first electrode, Forming a drive section including the first electrode and the second electrode.
[0014]
An electronic device according to the present invention includes a three-dimensional structure using a substrate having a flat portion, wherein the three-dimensional structure includes a displaceable main body formed on a flat portion of the substrate, A first electrode formed on the flat portion and connected to the main body, a linear bent portion formed on the substrate that is not completely separated, and a portion of the substrate along the bent portion; A device provided with an inclined portion formed by bending and a second electrode which is formed so as to have a predetermined interval between the first electrode and the inclined portion and forms a driving portion together with the first electrode. It is.
[0015]
In the three-dimensional structure according to the present invention or the electronic device according to the present invention, when a voltage is applied between the first electrode and the second electrode, the first electrode is displaced by an electrostatic force between the two electrodes. Along with the displacement of the first electrode, a mirror having, for example, a reflection film as a main body is displaced, and a relative angle with respect to the incident light changes, thereby deflecting the incident light.
[0016]
In the method for manufacturing a three-dimensional structure according to the present invention, a displaceable main body portion, a first electrode connected to the main body portion, and a pair with the first electrode are formed on the flat portion of the substrate, and are not connected to the main body portion. A second electrode is formed. Next, the substrate is selectively removed to form a straight bend that is not completely separated. After that, a part of the substrate is bent along the bent part to form an inclined part, so that a predetermined perpendicular to the surface of the substrate is provided between the second electrode and the first electrode. Are provided. As a result, a driving unit including the first electrode and the second electrode is formed.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0018]
[First Embodiment]
FIG. 1 shows a configuration of a three-dimensional structure according to the first embodiment of the present invention. This three-dimensional structure is used to deflect laser light emitted from a laser diode (not shown) in electronic equipment such as a laser scanner or a bar code reader. And drive units (actuators) 30A, 30B, 30C, 30D for oscillating the mirror 20.
[0019]
As the substrate 10, for example, a semiconductor substrate having a flat surface such as a silicon substrate is used. This is because, since the silicon substrate generally has no internal stress, even if the mirror 20 is formed using its surface, the mirror 20 does not warp. In particular, silicon dioxide (SiO 2) is formed on the surface of a holding substrate made of a semiconductor such as silicon. ₂ The SOI (Silicon On Insulator) substrate, which has a structure in which an oxide film such as silicon oxide) and a semiconductor thin film such as silicon are stacked in this order, requires much more manufacturing process than forming a three-dimensional structure by micromachining a bulk substrate. It is more preferable because it is simplified.
[0020]
The mirror 20 is formed using a flat surface of the surface of the substrate 10, and a reflective film 21 such as an aluminum (Al) film is formed on the surface. The mirror 20 is separated from the surrounding substrate 10 by, for example, anisotropic etching, and is provided with two torsion hinge portions 22A and 22B provided between two opposing sides of the mirror 20 and the substrate 10. Only supported by the substrate 10.
[0021]
The drive units 30A, 30B, 30C, and 30D include first drive units 30A and 30B that swing the mirror 20 to the upper right in FIG. 1 (hereinafter, referred to as “the other side”) around the torsion hinges 22A and 22B. It comprises second driving units 30C and 30D for swinging the mirror 20 in the opposite direction to the lower left (hereinafter referred to as “front side”). The driving section 30A and the driving section 30C are provided on the same side of the mirror 20 as the torsion hinge section 22A so as to be adjacent to the torsion hinge section 22A. The driving section 30B and the driving section 30D are provided on the same side of the mirror 20 as the torsion hinge section 22B so as to be adjacent to the torsion hinge section 22B.
[0022]
Each of the driving units 30A, 30B, 30C, and 30D has a comb-shaped first electrode 31 and a second electrode 32 that mesh with each other. The first electrode 31 is formed on a flat portion of the substrate 10 and is connected to the mirror 20. The second electrode 32 is formed on an inclined portion of the substrate 10 described later.
[0023]
In the present embodiment, a straight bent portion 11 that is not completely separated is formed on the substrate 10 as described later, and the inclined portions 12A and 12B that are bent at the bent portion 11 and partially inclined. It has become. The second electrode 32 of the first driving unit 30A, 30B is formed on the inclined part 12A, and the second electrode 32 of the second driving part 30C, 30D is formed on the inclined part 12B. The inclined portions 12A and 12B are bent downward with respect to the flat portion of the substrate 10, so that the comb teeth at the tip of the second electrode 32 project above the flat portion of the substrate 10. Thus, an interval 33 in the direction perpendicular to the surface of the substrate 10 is provided between the second electrode 32 and the first electrode 31. The inclined portions 12A and 12B are inclined downward with respect to the flat portion of the substrate 10 and in directions opposite to each other. In the present embodiment, the inclination angles of the inclined portions 12A and 12B are, for example, 1.2 degrees, and the interval 33 is, for example, 15 μm.
[0024]
FIG. 2 is an enlarged view of the driving unit 30A. Here, the substrate 10 is formed by depositing silicon dioxide (SiO 2) on the surface of a holding substrate 13 made of a semiconductor such as silicon. ₂ ), And an SOI substrate having a structure in which a semiconductor thin film 15 such as silicon is laminated in this order. The mirror 20, the first electrode 31, and the second electrode 32 are formed using the semiconductor thin film 15. Note that the first electrode 31 and the second electrode 32 may be formed by selectively adding an impurity such as phosphorus (P) or boron (B) to the semiconductor thin film 15 to impart conductivity. Alternatively, a wiring pattern formed of aluminum or the like on the semiconductor thin film 15 may be used. In this case, the impurity only needs to be added to at least the comb-like portions of the first electrode 31 and the second electrode 32. For example, the impurity is added to the entirety of the first electrode 31 and the second electrode 32. Or it may be added only to a part including a comb-shaped part.
[0025]
Between the first electrode 31 and the second electrode 32, there is provided a voltage applying unit 34 for giving a potential difference between the two. The voltage applying unit 34 drives the mirror 20 together with the first electrode 31 by an electrostatic force acting between the first electrode 31 and the second electrode 32.
[0026]
The bent portion 11 has a configuration in which the oxide film 14 and the semiconductor thin film 15 are left by selectively removing the holding substrate 13 by anisotropic etching to form an inverted V-shaped groove 11A. I have. A resist 16 is injected and fixed in the groove 11A in order to maintain a desired bending angle.
[0027]
Further, the bent portion 11 forms a groove 11B in the semiconductor thin film 15 to reduce the film thickness, and also provides a through hole 11C penetrating the semiconductor thin film 15 and the oxide film 14, thereby facilitating the bending of the substrate 10. Is preferred. The depth of the groove 11B, the size and the number of the through holes 11C, and the like can be determined according to the thickness of the semiconductor thin film 15.
[0028]
This three-dimensional structure can be manufactured, for example, as follows. FIGS. 3 to 6 show cross sections along the line III-III in FIG.
[0029]
First, as shown in FIG. 3A, as a substrate 10, an oxide film having a thickness of, for example, about 0.5 μm to 1 μm is formed on a surface of a holding substrate 13 having a thickness of, for example, 300 μm made of silicon. An SOI substrate having a structure in which a semiconductor thin film 15 made of silicon and having a thickness of, for example, 10 μm is stacked in this order is prepared.
[0030]
Next, as shown in FIG. 3B, using a mask (not shown) manufactured in advance, for example, RIE (Reactive Ion Etching) using ICP (Inductively Coupled Plasma). Then, a pattern of the mirror 20, the first electrode 31 (see FIG. 1), and the second electrode 32 (see FIG. 1) is formed on the semiconductor thin film 15. At this time, the through hole 11C of the bent portion 11 is also formed in the semiconductor thin film 15 at the same time. The through-hole 11 </ b> C is formed so as to reach the surface of the oxide film 14.
[0031]
The first electrode 31 and the second electrode 32 may be formed by selectively adding an impurity such as phosphorus or boron to the semiconductor thin film 15 to impart conductivity, or a mirror may be formed in a subsequent step. A wiring pattern of aluminum or the like may be formed on the semiconductor thin film 15 at the same time when the reflection film 21 is formed on the semiconductor film 20.
[0032]
Subsequently, as shown in FIG. 3C, a groove 11B of the bent portion 11 is formed in the semiconductor thin film 15 by RIE using, for example, ICP, using another mask that has been formed in advance. The thickness of the semiconductor thin film 15 in the portion 11 is reduced.
[0033]
Next, as shown in FIG. 4A, a thermal oxide film 41 having a thickness of, for example, 400 nm is formed on both surfaces of the substrate 10.
[0034]
Subsequently, as shown in FIG. 4B, the thermal oxide film 41 formed on the holding substrate 13 side of the substrate 10 is formed by using, for example, photolithography and buffered hydrogen fluoride (Buffered Hydrogen Fluoride; BHF). Patterning is performed by etching. Thus, a thermal oxide film mask 42 for wet anisotropic etching of the holding substrate 13 is formed.
[0035]
Next, as shown in FIG. 4C, using this thermal oxide film mask 42, wet anisotropic etching is performed using, for example, tetramethylammonium hydroxide (TMAH). As a result, an inverted V-shaped groove 11A is formed, and the bent portion 11 having the grooves 11A and 11B and the through hole 11C is formed. Further, the region of the holding substrate 13 corresponding to the mirror 20 is also removed.
[0036]
Subsequently, as shown in FIG. 5A, a resist 16 is injected into the groove 11A and baked at, for example, 150 ° C.
[0037]
Next, as shown in FIG. 5B, the thermal oxide film 41 and the thermal oxide film mask 42 are removed by etching using, for example, a 49% concentration hydrogen fluoride (HF) solution. At this time, the oxide film 14 (buried oxide film) sandwiched between the holding substrate 13 and the semiconductor thin film 15 remains, but the exposed oxide film 14 (surface oxide film) becomes the thermal oxide film 41 and the thermal oxide film mask 42. Removed with. Thereby, the mirror 20 is separated from the substrate 10 except for the twist hinge portion 22. Further, the oxide film 14 inside the through hole 11C is also removed, so that the through hole 11C reaches the surface of the holding substrate 13 through the semiconductor thin film 15 and the oxide film 14. Therefore, the bent portion 11 is not completely separated, and is partially connected by the semiconductor thin film 15 and the oxide film 14. After the etching is completed, the hydrofluoric acid is removed by washing, for example, carbon dioxide (CO 2). ₂ 2.) Critical drying is performed by applying pressure in an atmosphere.
[0038]
Subsequently, as shown in FIG. 6A, a bending jig 43 having two angled flat surfaces 43A and 43B is prepared in advance, and the substrate 10 is placed on the bending jig 43. Then, the temperature is raised to, for example, 150 ° C. to soften the resist 16 again.
[0039]
Next, as shown in FIG. 6B, the substrate 10 is bent at the bent portion 11 along the planes 43A and 43B of the bending jig 43 to form inclined portions 12A and 12B. After that, the entire substrate 10 is cooled and fixed, for example, by returning to normal temperature. The angle at which the substrate 10 can be bent can be arbitrarily adjusted by changing the angle formed by the planes 43A and 43B of the bending jig 43.
[0040]
Subsequently, the reflection film 21 is formed by evaporating an aluminum film using, for example, a shadow mask. At this time, a wiring pattern or an electrode pad may be simultaneously formed on the first electrode 31 and the second electrode 32 as necessary. The reflection film 21 and the electrode pads are formed by depositing gold (Au) or aluminum during the process, that is, before the mirror 20 is separated from the substrate 10 except for the torsion hinge 22, for example. And may be formed by patterning. Thus, the three-dimensional structure shown in FIG. 1 is completed.
[0041]
In this three-dimensional structure, for example, when a predetermined voltage is applied between the first electrode 31 and the second electrode 32 by the voltage applying unit 34 in the driving units 30A and 30B, the first electrode 31 is turned on. It is displaced by being attracted to the second electrode 32 and rotating toward the near side (see the arrow A in FIG. 2), and the mirror 20 rotates toward the near side with the displacement of the first electrode 31. Further, for example, in the driving units 30C and 30D, when a predetermined voltage is applied between the first electrode 31 and the second electrode 32 by the voltage applying unit 34, the first electrode 31 is changed to the second electrode 32. As the first electrode 31 is displaced by the rotation of the first electrode 31, the mirror 20 is rotated to the other side. As a result, the angle of the mirror 20 relative to the incident light changes, and the incident light is deflected. In this three-dimensional structure, the substrate 10 is bent at the bent portion 11 that is not completely separated to form the inclined portions 12A and 12B, and the second electrodes 32 are formed on the inclined portions 12A and 12B. Since the interval 33 is provided between the first electrode 31 and the second electrode 32, the tensile strength of the bent portion 11 is improved as compared with the conventional configuration in which the comb teeth are bonded to the substrate with a resist. I do. Further, since the bent portion 11 is not completely separated, it is possible to apply a voltage to the electrodes 31 and 32 via the bent portion 11 or the wiring pattern formed thereon, and it is possible to apply a voltage on the resist as in the conventional case. The electrical reliability is higher than the configuration in which a wiring pattern is formed on the substrate.
[0042]
FIG. 7 is a characteristic curve showing the relationship between the voltage applied between the first electrode 31 and the second electrode 32 and the rotation angles of the first electrode 31 and the mirror 20. The rotation angle of the mirror 20 according to the configuration of the present embodiment is a maximum of 3.2 degrees. Note that the characteristic curve of the rotation angle shows non-linearity, and it can be seen that the mirror 20 is driven by the electrostatic force between the electrodes.
[0043]
As described above, in the present embodiment, the substrate 10 is bent at the bent portion 11 that is not completely separated to form the inclined portions 12A and 12B, and the second electrode 32 is formed at the inclined portions 12A and 12B. Thus, since the space 33 is provided between the first electrode 31 and the second electrode 32, a complicated structure such as bonding of substrates is not required, and a three-dimensional structure having excellent mechanical strength and high electric reliability is provided. The structure can be realized with a simple configuration and manufacturing process. Further, the accuracy of the angle at which the substrate 10 can be bent can be increased to about 0.2 degrees as compared with the conventional case, and the yield can be improved.
[0044]
In addition, especially in a bar code reader application, for example, when narrowing a laser beam to about 200 μm at a distance of about 80 mm, the light emitting unit and the mirror need to have a size of 0.63 mm or more due to the diffraction limit. In order to further narrow the beam, a larger mirror is required. Therefore, in consideration of the range of the mirror surface when the alignment and the angle are provided, the size of the mirror is required to be 1 mm level, but in the present embodiment, sufficient mechanical strength to drive such a large mirror 20 is required. It is possible to realize a three-dimensional structure having
[0045]
In particular, since the substrate 10 has a structure in which the oxide film 14 and the semiconductor thin film 15 are laminated on the surface of the holding substrate 13 in this order, the manufacturing process is more difficult than forming a three-dimensional structure by micromachining a bulk substrate. Can be greatly simplified.
[0046]
Particularly, since the groove 11B and the through hole 11C are provided in the semiconductor thin film 15, the bent portion 11 can be further easily bent.
[0047]
Further, when the substrate 10 is bent at the bending portion 11, the substrate 10 is made to follow the bending jig 43 having two angled flat surfaces 43A and 43B. It can be arbitrarily adjusted by changing the angle between the flat surfaces 43A and 43B.
[0048]
[Second embodiment]
FIG. 8 shows a method for manufacturing a three-dimensional structure according to the second embodiment of the present invention. In the present embodiment, the thickness of the inclined portions 12A and 12B is reduced by providing a concave portion on the back surface of the substrate 10 so that the substrate 10 can be bent on a flat support table. This eliminates the need to bend the substrate 10 using the bending jig 43.
[0049]
First, as shown in FIG. 8A, the first embodiment is performed except that the thickness of the inclined portions 12A and 12B is reduced by forming a concave portion 13A on the back surface of the holding substrate 13. As in the case of FIG. 5B, the mirror 20, the first electrode 31 (see FIG. 1), the second electrode 32 (see FIG. 1), and the bent portion 11 are formed on the substrate 10. The recess 13A of the holding substrate 13 can be formed by, for example, anisotropic etching. Further, as the order of the steps, the steps of FIGS. 3 to 5 may be performed after forming the concave portion 13A of the holding substrate 13 first, as in the first embodiment. Alternatively, the recess 13A may be formed in the holding substrate 13 after performing the steps of FIGS. 3 to 5 of the first embodiment.
[0050]
Next, as shown in FIG. 8B, the substrate 10 is placed on a flat support table 51, and an end 11D of the thinned portion facing the bent portion 11 is pushed in the direction of arrow 52, The substrate 10 is bent at the bent portion 11 until the end portion 11D contacts the support table 51 to form inclined portions 12A and 12B. As a result, an interval 33 (see FIG. 1) is formed between the first electrode 31 and the second electrode 32. The angle at which the substrate 10 is bent can be arbitrarily adjusted by the depth D of the recess 13A.
[0051]
As described above, according to the present embodiment, the concave portions are provided on the back surface of the substrate 10 to reduce the thickness of the inclined portions 12A and 12B, so that the substrate 10 can be bent on a flat support base. In addition, the bending jig 43 becomes unnecessary. The angle at which the substrate 10 is bent can be arbitrarily adjusted by the depth D of the recess 13A.
[0052]
As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above embodiment, and can be variously modified. For example, the dimensions of each part, the material of the substrate, the film thickness, the process conditions, and the like can be changed without departing from the gist of the present invention. For example, instead of TMAH, potassium hydroxide (KOH), hydrazine, ethylenediamine-pyrocatechol-water (EPW) and the like can be used.
[0053]
Further, in the above embodiment, the resist 16 which is softened at, for example, about 150 ° C. is injected into the groove 11A, but a metal such as a low melting point solder may be used instead of the resist 16. Furthermore, if a material that melts at a higher temperature than the resist 16 or the low melting point solder, for example, a metal such as a high melting point solder is used, it can be adapted for use in a higher temperature environment.
[0054]
Further, in the above-described embodiment, the configuration of the bent portion 11 has been specifically described. However, by changing the configuration of the bent portion 11 according to the thickness of the semiconductor thin film 15, the ease of bending of the bent portion 11 is improved. Can be adjusted. For example, as shown in FIG. 9, only the groove 11B may be provided in the semiconductor thin film 15 and the through hole 11C may not be provided. Alternatively, as shown in FIG. 10, for example, when the thickness of the semiconductor thin film 15 is small, only the through hole 11C may be provided and the groove 11B may not be provided. Conversely, as shown in FIG. 11, when the thickness of the semiconductor thin film 15 is large, a narrower groove 11E may be provided on the bottom surface of the groove 11B.
[0055]
In addition, in the above-described embodiment, the case where both the oxide film 14 and the semiconductor thin film 15 are left in the bent portion 11 has been described. However, only the semiconductor thin film 15 may be left. As shown in FIG. 12, only the oxide film 14 may be left. However, since the semiconductor thin film 15 made of silicon is more resistant to bending than the oxide film 14 made of silicon dioxide, it is preferable that the semiconductor thin film 15 remains.
[0056]
Further, in the above embodiment, an optical deflector having a galvano mirror driven by electrostatic force as the mirror 20 has been described as an example. However, the present invention relates to an optical deflector using a polygon mirror (rotating polygon mirror). Is also applicable.
[0057]
In addition, in the above embodiment, the case where the three-dimensional structure of the present invention is applied to an optical deflector in an electronic device such as a laser scanner or a bar code reader has been described as an example. Compact barcode reader, beam scanner, laser printer, optical switch, projector, beam scanner for laser show, display, two-dimensional barcode reader, distance sensor, laser sonar, confocal microscope, laser microscope, optical prototyping, laser processing machine , PtoP (peer-to-peer) optical communication, optical communication, and other electronic devices.
[0058]
【The invention's effect】
As described above, according to the three-dimensional structure according to any one of claims 1 to 11, and the electronic device according to claim 14 or claim 15, the third device formed on the flat portion of the substrate. One electrode, a bent portion formed on the substrate that is not completely separated, an inclined portion formed by bending the substrate at the bent portion, and a first electrode between the inclined portion and the first electrode. And a second electrode formed so as to have a predetermined interval, so that a complicated structure such as bonding of substrates is not required, and a three-dimensional structure having excellent mechanical strength and high electrical reliability is provided. , Can be realized with a simple configuration and a manufacturing process. Further, the accuracy of the angle at which the substrate can be bent can be increased, and the yield can be improved.
[0059]
In addition, a large mirror is required especially in a barcode reader application. According to the present invention, a three-dimensional structure having sufficient mechanical strength capable of driving such a large mirror is realized. Becomes possible.
[0060]
In particular, according to the three-dimensional structure of the sixth aspect, since the substrate has a structure in which an oxide film and a semiconductor thin film are laminated on the surface of the holding substrate in this order, the three-dimensional structure is formed by micromachining the bulk substrate. The manufacturing process can be significantly simplified as compared to forming the structure.
[0061]
Further, in particular, according to the three-dimensional structure according to claim 8, since the bent portion has at least one of the groove and the through hole in the semiconductor thin film, the bent portion can be further easily bent. it can.
[0062]
In addition, in particular, according to the three-dimensional structure according to claim 11, since the thickness of the inclined portion is reduced by providing the concave portion on the back surface of the substrate, the substrate is bent on a flat support base. Can be. The angle at which the substrate is bent can be arbitrarily adjusted depending on how thin the thickness is.
[0063]
According to the method for manufacturing a three-dimensional structure according to the twelfth or thirteenth aspect, the substrate is bent along the bent part that is not completely separated to form the inclined part, so that the second electrode and the two-dimensional structure can be formed. Since a predetermined space is provided between the first electrode and the first electrode, a space perpendicular to the surface of the substrate can be formed between the second electrode and the first electrode by a simple process. it can. In addition, the mechanical strength and electrical reliability of the electrode can be improved.
[0064]
In particular, according to the three-dimensional structure manufacturing method of the thirteenth aspect, in the step of bending the substrate at the bending part, the substrate is bent along the jig having two angled flat surfaces. The angle can be adjusted arbitrarily by changing the angle between the two planes of the jig.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating an example of a configuration of a three-dimensional structure according to a first embodiment of the present invention.
FIG. 2 is an enlarged perspective view showing one of the driving units shown in FIG.
FIG. 3 is a cross-sectional view showing a method of manufacturing the three-dimensional structure shown in FIG. 1 in the order of steps.
FIG. 4 is a cross-sectional view for explaining a step that follows the step of FIG.
FIG. 5 is a cross-sectional view for describing a step that follows the step of FIG.
FIG. 6 is a cross-sectional view for describing a step that follows the step of FIG.
FIG. 7 is a characteristic curve showing a relationship between a voltage applied between electrodes shown in FIG. 1 and a rotation angle of a mirror.
FIG. 8 is a sectional view illustrating a method for manufacturing a three-dimensional structure according to the second embodiment of the present invention.
FIG. 9 is a perspective view illustrating another configuration example of the bent portion illustrated in FIG.
FIG. 10 is a perspective view illustrating still another configuration example of the bent portion illustrated in FIG.
FIG. 11 is a perspective view illustrating still another configuration example of the bent portion illustrated in FIG.
FIG. 12 is a perspective view illustrating still another configuration example of the bent portion illustrated in FIG.
FIG. 13 is a plan view and a front view illustrating a configuration example of a conventional vertical comb actuator.
FIG. 14 is a plan view and a front view illustrating another configuration example of the conventional vertical comb tooth actuator.
FIG. 15 is a perspective view for explaining a conventional method for forming an angle on a comb-shaped electrode.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... board | substrate, 11 ... bent part, 12A, 12B ... inclined part, 13 ... holding board, 13A ... recessed part, 14 ... oxide film, 15 ... semiconductor thin film, 16 ... resist, 20 ... mirror, 21 ... reflection film, 30A , 30B, 30C, 30D: drive unit, 31: first electrode, 32: second electrode, 33: interval, 34: voltage application unit

Claims (15)

A three-dimensional structure using a substrate having a flat portion,
A displaceable main body formed on a flat portion of the substrate,
A first electrode formed on the flat portion of the substrate so as to be connected to the body portion;
A straight bent portion that is not completely separated from the substrate,
An inclined portion formed by bending a part of the substrate along the bent portion,
A three-dimensional structure, comprising: a second electrode that is formed on the inclined portion so as to have a predetermined interval between the first electrode and the first electrode, and that forms a driving unit together with the first electrode. body. The three-dimensional structure according to claim 1, wherein the first electrode and the second electrode have a comb-like shape that meshes with each other. A voltage applying means for applying a potential difference between the first electrode and the second electrode, wherein the main body is driven together with the first electrode by an electrostatic force generated between the electrodes. Item 3. The three-dimensional structure according to Item 1. The three-dimensional structure according to claim 1, wherein the main body is a mirror having a reflective film. The drive unit includes a first drive unit that rotationally drives the main body unit in one direction, and a second drive unit that rotationally drives the main body unit in a direction opposite to the direction, and swings the mirror. The three-dimensional structure according to claim 4, wherein the three-dimensional structure is moved. The three-dimensional structure according to claim 1, wherein the substrate has a structure in which an oxide film and a semiconductor thin film are laminated on a surface of a holding substrate in this order. The three-dimensional structure according to claim 6, wherein the bent portion has a configuration in which at least one of the oxide film and the semiconductor thin film is left by selectively removing the holding substrate. The three-dimensional structure according to claim 7, wherein the semiconductor thin film forming the bent portion has at least one of a groove and a through hole. The three-dimensional structure according to claim 6, wherein the first electrode and the second electrode are provided on the semiconductor thin film. 7. The three-dimensional structure according to claim 6, wherein a mirror having a reflection film as the main body is provided on the semiconductor thin film. The inclined portion has a thickness reduced by providing a concave portion on the back surface of the substrate, and a part of the substrate is formed until the end of the inclined portion facing the bent portion contacts the support base. The three-dimensional structure according to claim 1, wherein the three-dimensional structure is bent at a bent portion. A method for manufacturing a three-dimensional structure using a substrate having a flat portion,
Forming a displaceable main body, a first electrode connected to the main body, and a second electrode paired with the first electrode and not connected to the main body on a flat portion of the substrate; When,
Selectively removing the substrate, forming a straight bend that is not completely separated,
A predetermined interval is provided between the second electrode and the first electrode by bending a part of the substrate along the bent portion to form an inclined portion; Forming a driving section comprising a first electrode and a second electrode. 13. The method of manufacturing a three-dimensional structure according to claim 12, wherein, in the step of bending the substrate at the bending portion, the substrate is made to follow a jig having two angled flat surfaces. An electronic device including a three-dimensional structure using a substrate having a flat portion,
The three-dimensional structure,
A displaceable main body formed on a flat portion of the substrate,
A first electrode formed on the flat portion of the substrate so as to be connected to the body portion;
A straight bent portion that is not completely separated from the substrate,
An inclined portion formed by bending a part of the substrate along the bent portion,
An electronic device, comprising: a second electrode that is formed on the inclined portion so as to have a predetermined distance between the first electrode and the first electrode and that forms a driving unit together with the first electrode. The electronic device according to claim 14, wherein the main body is a mirror having a reflective film.

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