JPH0815284A - Fine structure, its formation, atomic force microscope using the structure, scanning tunnel current microscope and light deflecting apparatus - Google Patents

Abstract

PURPOSE:To lessen the breaking at the time of formation and improve the precision and yeild ratio by sticking two substrates for which etching process is carried out to each other in the sides on which the grooves for a fine structure are formed and etching and removing a part from a substrate plane formed by a first etching. CONSTITUTION:A silicon nitride film 302 is formed as a thin film on a substrate 301 on which a fine structure is to be formed by LPCVD film forming method from dichlorosilane and ammonia gas. Then, a resist mask is formed by a mask aligner apparatus and a part 303 to be etched of the nitride film is removed by reactive ion etching. Next, etching is carried out by a heated aqueous solution of potassium hydroxide to form a frame body part 309. Further, a silicon oxide film is formed on another structure holding substrate 306 by sputtering and a cantilever seat part 307 is formed by ion milling method. Then, the substrates 301 and 306 are stuck mutually. After that, etching is carried out to separate the frame body part 309 and the cantilever part 308 and the frame body part 309 is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a silicon thin plate structure, and more particularly to a method of manufacturing a minute structure applied to a detection probe of AFM or STM.

[0002]

2. Description of the Related Art A silicon microstructure such as a cantilever manufactured by a micromechatronics technique is used for an atomic force microscope (AFM) or a scanning tunneling current microscope (S).
(TM) probe section and a micro-deflector of an optical deflector. In these devices, the microstructure is made of silicon, silicon oxide, or the like.

As a method for producing these microstructures, the following methods can be mentioned. (1) A method of forming a structure part with a thin film, and (2) a method of joining single crystal substrates forming a structure.

Here, a method of forming a microstructure using the methods (1) and (2) will be described.

FIG. 16 shows a method of forming a cantilever using a thin film forming method. First, as shown in FIG. 16A, a sacrifice layer 1602 formed of silicon oxide or the like is formed on a substrate 1601 by a vacuum film formation method, and then,
A cantilever member 1604 such as a polysilicon film is deposited as shown in (b). Next, the cantilever 1603 is removed by etching away the sacrificial layer as shown in (c).
To form.

FIG. 17 shows a method of forming a microstructure using single crystal silicon. As shown in FIG. 17A, a Pyrex glass layer is formed on the first substrate 1701. Next, as shown in (b), the second substrate 1703 is bonded using a method such as an anodic bonding method. Then, as shown in (c), the second substrate 1703 is ground to a desired thickness by using a mechanical polishing method or an etching method. Finally, (d)
As shown in FIG. 5, the unnecessary portion is removed by etching to form a cantilever portion 1704 and a pedestal portion 1705.

[0007]

However, in these methods, the method (1) has a problem that it is difficult to control the stress at the time of film formation, and the microstructure is easily deformed by residual stress. Further, the method (2) has a drawback in that the thickness of the bonded substrate cannot be reduced due to a problem of destruction due to handling at the time of bonding, and when the etching removal method is used, the process time is long and the mass productivity is low. In addition, there is also a problem that other components are affected by etching. Further, even in the method by mechanical polishing, there are problems that breakage and distortion are likely to occur during polishing, and there is a problem of contamination by an abrasive.

Therefore, an object of the present invention is to solve these problems and to provide a method for forming a microstructure in which the destruction at the time of forming the microstructure is significantly reduced and the precision and the yield are improved. .

[0009]

According to the present invention, there is provided a first etching step for removing a part of a substrate from one surface by etching to form a thin plate portion in the substrate, and etching a part of a surface opposite to the etching surface. A second etching step of removing and forming a groove for forming a microstructure in a thin plate forming portion, and a step of joining a substrate subjected to the two etching steps to another substrate on the surface on which the groove for forming a microstructure is formed. A method for forming a microstructure, the method including a step of removing at least a part of the thin plate portion from a substrate surface on which the thin plate portion is formed by the first etching step to separate the thin plate portion from the substrate; Provided are an atomic force microscope, a scanning tunneling current microscope, and a light deflecting device using the microstructure and the microstructure obtained by the method.

That is, in the method of the present invention, by providing the thin plate portion and the frame body portion for holding the thin plate portion, (1)
Deflection caused by residual stress at the time of film formation, (2) It is possible to significantly suppress the destruction of the structure caused by scratches due to handling, and the precision and yield of forming microstructures are dramatically improved. improves. Further, since the etching time after joining can be shortened, mass productivity is improved, and at the same time, the etching liquid has little influence on other constituent materials.

At the same time, in the method of the present invention, since the etching amount or polishing amount can be suppressed to a small value,
The amount of etchant consumed and the contamination of the etching apparatus are reduced, and excellent productivity can be achieved. Further, the frame portion can be easily regenerated as a silicon raw material for a polycrystalline solar cell or the like, and has a recycling effect on the raw material surface.

[0012]

EXAMPLES The present invention will be described below in detail based on the examples shown in the drawings, but the present invention is not limited thereto.

(Embodiment 1) FIGS. 1 to 3 show a first embodiment of a method for forming a microstructure according to the present invention. FIG. 1 is a perspective view showing the structure of a cantilever formed by using the microstructure forming method of the present invention, and FIG. 2 is a perspective view showing the structure of a silicon substrate used in the microstructure forming method of the present embodiment. 3A to 3D are process diagrams showing a method for manufacturing a microstructure of the present invention.

1 to 3, 101 is a cantilever portion, 102 is a pedestal portion, 103 is a structure holding substrate portion, 201 is a frame portion, 202 is a thin plate portion, 301 is a microstructure forming substrate, and 302 is nitrided. Silicon film, 303 is etched portion, 304 is (111) crystal plane of silicon, 30
5 is a groove portion, 306 is a structure holding substrate, 307 is a pedestal portion,
308 is a cantilever portion.

In FIG. 1, the cantilever portion 101 is connected to the structure holding substrate 103 via the pedestal portion 102. This cantilever structure can be applied as various minute structure parts such as a drive lever for a detection part of an AFM or STM, an optical deflector, and the like. In the microstructure forming substrate of FIG. 2, the thin plate portion 202 is inside the frame portion 201, and the cantilever portion 101 of FIG. 1 is formed on each thin plate portion 202. At this time, the frame plate portion 101 and the thin plate portion 102 are
It is formed by removing a part of a silicon (100) single crystal substrate by etching. Grooves (not shown) along the microstructure are formed on the back surface of this thin plate portion, the back surface is joined to another substrate, and then etching is performed from the top surface to form the frame portion 101 in the above-mentioned groove portion. The substrate is cut off, and the cantilever portion 101, which is the microstructure shown in FIG. 1, is formed on another substrate.

The manufacturing process, which is the basic part of the method for forming a microstructure of the present invention, will be described in detail below based on the manufacturing process of the cantilever of this embodiment shown in FIG.

In FIG. 3A, the silicon nitride film 30 is formed.
For forming No. 2, the LPCVD film forming method using dichlorosilane and ammonia gas as raw materials was deposited on the microstructure forming substrate 301 to a thickness of 0.2 μm. Next, a resist mask is formed using a mask aligner device, and the nitride film in the etched portion 303 is removed by reactive ion etching. In addition, reactive ion etching is
It was performed using carbon tetrafluoride.

Next, this substrate was etched with a potassium hydroxide aqueous solution heated to about 110 ° C. for a predetermined time to form a frame body portion 309 of FIG. 3B. Here, the (111) crystal plane 304 of silicon appears due to the difference in etching rate depending on the crystal plane of silicon. In this embodiment, the thin plate portion has a thickness of 20 μm.

Although potassium hydroxide is used as the etching solution in this embodiment, an etching solution capable of anisotropically etching silicon such as hydrazine, ammonia and tetramethylammonium hydroxide is used. Good. Further, it is also possible to manufacture it with high thickness accuracy by using a known method such as an electrolytic etching method. Further, isotropic etching using a mixed aqueous solution of hydrofluoric acid and nitric acid can be applied to this embodiment to form the frame portion 201 and the thin plate portion 202 in FIG. next,
As shown in FIG. 3C, a silicon oxide film having a thickness of 3 μm is formed on the structure holding substrate 306 which is another substrate by a sputtering method.
Then, the cantilever pedestal portion 307 was formed using an ion milling method.

Next, as shown in FIG. 3D, the microstructure forming substrate 301 and the structure holding substrate 306 were bonded together. In this case, an epoxy adhesive (not shown) was applied to the joint area by screen printing and bonded.

Next, as shown in FIG. 3E, etching is performed by reactive ion etching from the upper surface in the figure using sulfur hexafluoride to form a fine structure forming substrate 301.
The frame body portion 309 and the cantilever portion 308 were separated, and the frame body portion 309 was removed.

In this example, the size of the cantilevers was 200 μm × 40 μm, and 54 cantilevers were simultaneously formed in a 4-inch silicon wafer. In this example, the amount of warp of the cantilever is 1 μm.
Below, it was extremely small. (Embodiment 2) FIGS. 4 to 7 are views showing a second embodiment of the method for forming a microstructure according to the present invention. FIG. 4 is a structural diagram of a detection probe portion of a torsion type atomic force microscope (AFM) manufactured by applying the microstructure forming method of this embodiment,
FIG. 5 is a process diagram showing the manufacturing process of this embodiment, FIG. 6 is a plan view of the probe-forming mold material, and FIG. 7 is a cross-sectional view of the probe-forming mold material of FIG.

4 and 5, 401 is a lever portion, 402 is a hinge portion, 403 is a probe portion, 404 is a detection upper electrode lead portion, 405 is a contact electrode portion, 40
Reference numeral 6 is a contact portion, 407 is a pedestal portion, 408 is a detection lower electrode portion, and 409 is an electrostatic displacement detection circuit portion.

The structure and driving method of the detection probe of the atomic force microscope (AFM) formed in this embodiment will be described below.

In the AFM detection probe of FIG. 4, when the probe scans the detection sample surface with a scanning mechanism (not shown), the probe portion 403 is vertically displaced according to the unevenness of the sample surface. At this time, the lever portion 401 rotates about the center of the hinge portion 402 due to the twist of the hinge portion 402, and the distance between the upper electrode portion (not shown) formed on the back surface of the lever and the lower electrode portion 408 changes. To do. By detecting the amount of capacitance change at this time by the detection circuit 409, detection is performed as an uneven signal.

Next, the method for forming a microstructure of the present invention will be described in more detail with reference to the manufacturing process diagram of the AFM probe shown in FIG.

In FIG. 5, 501 is a fine structure forming substrate, 502 is a silicon nitride film, 503 is an etching portion,
504 is a (111) crystal plane of silicon, 505 is a groove,
Reference numeral 506 is an upper electrode for bonding and its lead portion, 507 is an upper electrode for detection and its lead part which are also partially used as the upper electrode for bonding, 508 is a detection circuit side substrate, 509 is a lower electrode for detection and 510 is a wire for joining. Lower electrode 511 is a pedestal portion, 51
Reference numeral 2 is a sacrifice layer, 513 is a contact portion, 514 is a probe connecting portion, and 515 is a probe portion.

In FIG. 5A, the silicon nitride film 50 is formed.
For formation of No. 2, the LPCVD film forming method using dichlorosilane and ammonia gas as raw materials was used to deposit 0.2 μm in thickness on the microstructure formation substrate 501 as in Example 1. Thereafter, as in the case of Example 1, a resist mask was formed using a mask aligner device, and the nitride film in the etched portion 503 was removed by the reactive ion etching method. In this example, reactive ion etching was performed using carbon tetrafluoride, and anisotropic etching was performed using tetramethylammonium hydroxide heated to 90 ° C. As in Example 1, (111) crystal plane 5 of silicon
04 appears due to the difference in etching rate depending on the crystal plane of silicon. In this example, the thin plate portion had a thickness of 15 μm.

Next, after the silicon nitride film on the back surface is entirely removed by reactive ion etching, the resist is used as a mask to carry out reactive ion etching using sulfur hexafluoride gas along the shape of the lever portion 401. Groove 507
Are simultaneously formed using aluminum vapor deposition and lift-off method. Here, FIG. 5C shows the detection circuit side substrate 508 on which an AFM detection circuit (not shown) is formed. The detection lower electrode 509 and the bonding lower electrode 510 were formed by vapor deposition of aluminum using the lift-off method.

Next, a low melting point glass film containing lead is formed to a thickness of 3 μm by a sputtering method, a lever pedestal portion 511 is formed by an ion milling method, and finally, a sputtering method is performed by using zinc oxide. And the etching method, the sacrificial layer 51
Formed 2.

FIG. 5D shows a microstructure forming substrate 501.
FIG. 6 is a diagram illustrating a state of joining the AFM detection circuit side substrate 508 and the AFM detection circuit side substrate 508. After aligning both substrates with the alignment marker, the bonding lower electrode 510 is the positive electrode and the bonding upper electrode 50.
By applying a DC voltage of 100 V for 5 minutes in an atmosphere of 100 ° C. with 7 as a negative electrode, the two substrates 501 and 5
08 was joined at the lever pedestal portion 511.

In the alignment, an infrared camera was used, and the alignment was performed by using markers made of a metal material formed on the bonding surfaces of the two substrates.

Next, etching is performed by reactive ion etching from the upper surface in the figure using sulfur hexafluoride to form the frame portion of the microstructure forming substrate 501, the lever portion 401, the hinge portion 402, and the pedestal portion 407. After the formed portion is separated, the frame body portion is mechanically removed to obtain a state as shown in FIG.

Next, as shown in FIG. 5 (f), a contact portion 513 is formed by an aluminum lift-off method to connect the detection upper electrode portion 506 and the bonding lower electrode portion 510 and the probe connection portion 514. Was formed by the gold lift-off method, and then the probe portion 515 was connected. After this, the sacrificial layer 512
Was removed by etching to complete the AFM probe. A mixed solution of hydrogen peroxide water and ammonia water was used for etching the sacrificial layer 512, and the etching solution was replaced with dichlorobenzene at 80 ° C. to prevent sticking of the lever portion to the substrate portion 508. After returning to room temperature, a freeze-drying method was used in which the solution was kept under vacuum to remove dichlorobenzene.

The probe portion 515 was formed by transferring a gold probe formed of a mold material. This method will be described with reference to FIGS. 6 and 7.

In FIGS. 6 and 7, 601 indicates a single crystal silicon (100) substrate, and 602 indicates a groove for forming a probe.

6 and 7, the groove portion 602 for forming the probe portion 515 is formed by anisotropic etching of the above-mentioned silicon single crystal. The probe portion 515 was formed by a vapor deposition method with a thickness of 1 μm of gold using the lift-off method.
The probe portion 515 was formed by transferring the probe by pressing the probe portion 515 onto the connecting portion 514 formed by depositing 0.1 μm of gold using chromium formed on the lever as an undercoat layer.

In the probe size of this embodiment, the lever portion 401 is 200 μm × 100 μm, and the hinge portion 402 is
Is 50 μm × 15 μm and the thickness is 1 μm.
It has a resonant frequency at Hz. The amount of warp of the lever portion was 2 μm or less, and the difference in the amount of warp between the levers formed at the same time was not detected.

In this example, the connection of the substrates was made by anodic bonding between aluminum and lead-containing glass.
Anodic bonding method between silicon and alkali-containing glass, epoxy adhesive, photosensitive adhesive, paste-like low melting point metal is formed in the connection portion by a method such as screen printing, and ultraviolet rays are used as necessary. Method of connecting by irradiation and temperature control, method of forming low melting point metal at the connection part using vacuum forming method and joining by heat treatment, connection by applying metal pressure shown in description of forming probe It is possible to apply other joining methods such as a method.

Further, in the AFM of this embodiment, the detection is carried out electrostatically, but the displacement of the probe can be carried out by another method such as an optical tip method. In that case, an electrode for detection is not required, and the probe configuration is simplified. Further, if necessary, it is possible to improve the detection sensitivity by forming a high reflectance member such as a metal in the light irradiation portion.

Further, the structure formed by the manufacturing method of this embodiment is a minute probe such as a detection probe for a scanning tunneling microscope (STM), a writing / reproducing probe for a memory system utilizing writing and detection by a probe. It can be widely applied as a method for manufacturing a structure.

(Embodiment 3) FIGS. 8 to 9 show a third embodiment of the method for forming a microstructure according to the present invention. FIG. 8 shows an example of a structure forming substrate used in this embodiment. FIG. 9 is a diagram showing a part, and FIG. 9 is a manufacturing process diagram of this embodiment.

This embodiment is an AFM having the same structure as that of the second embodiment.
A method of producing a detection probe using silicon oxide as a main constituent material will be described.

In FIGS. 8 and 9, 801 is a silicon single crystal bonding side substrate portion, 802 is a frame body portion, 803 is a thin plate portion, 804 is a silicon oxide portion formed by thermal oxidation, and 9
Reference numeral 01 is a silicon portion in a silicon substrate, 902 is a driving upper electrode portion, 903 is a crimping portion, 904 is a groove portion, 905 is a driving side substrate, 906 is a lever pedestal portion, 907 is a driving lower electrode, and 908 is a connecting portion. Reference numeral 909 is an extraction electrode portion, and 910.
Is a sacrifice layer portion, 911 is a resist, and 912 is a probe portion.

In FIG. 8, the frame body portion 802 and the thin plate portion 80
3 was formed as follows. First, the silicon oxide layer 802 was formed by thermal oxidation. The thermal oxidation was performed by holding the silicon substrate 801 at 1150 ° C. in a hydrogen-oxygen mixed atmosphere for a whole day and night.

Next, the silicon oxide layer in the etched portion is removed by using the photolithography method and the etching method using hydrofluoric acid. Next, etching was performed from one side of the silicon substrate 801 using a jig (not shown) to form a thin plate portion 803 on the silicon single crystal substrate. As the etching solution for the silicon substrate 801, potassium hydroxide was used as in Example 1.

Next, a method of manufacturing an AFM having the same structure as that of the second embodiment will be described in detail with reference to FIG.

FIG. 9A shows the silicon substrate 801 of FIG.
It is the figure which looked at from the cross section. Here, the thickness of the lower silicon oxide layer 804 is 10 μm.

FIG. 9B shows a state in which a groove portion 904 for cutting off, a driving electrode 902, and a pressure bonding portion 903 are formed. The groove portion 904 was formed to a depth of 4 μm by reactive etching using carbon tetrafluoride. Further, the driving upper electrode 902 and the pressure-bonding portion 903 have a thickness of 0.05 .mu.m with gold as a base and gold with a thickness of 0. It was formed by continuously sputtering 3 μm. The left and right crimp portions 903 are connected to the driving upper electrode 902 and the chip portion (not shown), respectively.

FIG. 9C shows the driving side substrate 905,
After forming the lever pedestal portion 906 made of silicon oxide to a thickness of 2 μm by the sputtering method, the driving lower electrode 90 is formed.
7, a connection portion 908, a lead electrode portion 909 are formed, and then a sacrifice layer 910 made of resist is formed. The lower electrode portion 907 for driving, the connecting portion 908, and the lead electrode portion 909 are made of chromium as a base and have a thickness of 0.05 μm.
m and gold were continuously sputtered for 1 μm.

FIG. 9D shows a state in which the structure forming substrate is pressure-bonded to the driving substrate 905. The pressure bonding at this time was performed by applying a force of about 1 kgf per 4 inch wafer. After that, the frame body portion was removed by the same method as in Example 1.

FIG. 9E is a diagram showing a method of forming the probe portion 912. A resist 911 is formed so that the probe forming portion has an inverse tapered shape, and the substrate is inclined with respect to the vapor deposition source. The probe part 912 was formed by rotating in this state.

FIG. 9F shows a state in which the sacrificial layer 912 and the resist 911 for forming the probe are removed. The resist was removed by an ashing method using oxygen plasma.

Further, in the present embodiment, it is possible to use a workable glass such as PEG3 photosensitive glass (manufactured by HOYA Co., Ltd.) as the structure forming substrate. In that case, the thin plate portion forming pattern is irradiated with ultraviolet rays, the mask material is removed, development is performed by heat treatment at about 600 ° C., and then, the unexposed portion is exposed by irradiation with ultraviolet rays. After that, etching is performed from one side with a 10% hydrofluoric acid solution using a jig (not shown) to form a structure forming substrate. Thereafter, by using the same steps as described above, it was possible to form the lever without warping.

(Embodiment 4) FIGS. 10 to 12 show a fourth embodiment of the method for producing a microstructure according to the present invention.
FIG. 10 is a microstructure manufactured using a silicon single crystal substrate, FIG. 11 is a diagram showing a manufacturing process of the microstructure, and FIG. 12 is a multi-type optical deflection of a projection display device with the microstructure. The example used as a container is shown.

10 to 12, 1001 to 10
Reference numeral 04 is a cantilever, 1005 is a pedestal portion, 1006 is a lower electrode portion, 1007 is an upper electrode portion, 1008 is an upper electrode lead portion, 1009 is a driving side substrate, 1101 is a silicon substrate, 1102 is a mask portion, 1103 is a groove portion, 1104 is A frame portion, 1105 is a thin plate portion, and 1106 to 1109 are cantilever portions.

In FIG. 10, by applying a voltage between the lower electrode 1006 and the upper electrode 1007, the cantilevers 1001 to 1004 are displaced according to their respective thicknesses. At that time, as the applied voltage is increased, the cantilever deforms in order from the smallest thickness 1001 until it hits the lower electrode. Therefore, it is possible to change the displacement angle of the lever by controlling the applied voltage.

Next, referring to FIG. 11, the cantilever 1
A method of manufacturing 001 to 1004 and the pedestal portion 1005 will be described.

FIG. 11 shows a method of forming a structure in the AA ′ cross section of FIG. 10, and FIG. 11A shows the single crystal silicon substrate 1101 to the thin plate portion 1105 using the same method as in the first embodiment.
A state in which the groove 1103 is formed is shown. Here, the groove portion 1103 was formed by using the same method as in the first embodiment.
A resist was used as the etching mask portion 1102. FIGS. 11B and 11C are views for explaining the step of forming a thickness change in the cantilevers 1106 to 1109, in which resist patterning is performed for each area where the thickness is changed, and an etching portion is formed separately, and dry etching is performed. By repeating the etching, microstructures having different thicknesses are formed. FIG. 11D shows a state in which the pedestal portion 1005 is also formed by the same method.

Next, a glass layer (not shown) functioning as an insulating layer and a bonding layer was deposited to a thickness of 0.2 μm on the lower surface of FIG. 11 (d) by a sputtering method.

Next, a sacrificial layer (not shown) made of a resist is formed on the lower electrode portion 1006 in FIG.
01, and subsequently the extraction electrode portion 1008 made of aluminum is formed.

Next, the extraction electrode portion 1008 was bonded to the glass layer (not shown) formed on the pedestal portion 1005 and the extraction electrode portion 1008 by an anodic bonding method using the positive electrode and the silicon substrate 1101 as the negative electrode. Thereafter, the microstructure portion was cut off from the thin plate portion 1105 by the reactive ion etching method using carbon tetrafluoride. Finally, the upper electrode portion 1007 functioning as a light reflecting layer was formed of aluminum by sputtering and etching, and then the resist was removed by oxygen plasma ashing to form a microstructure.

The cantilevers 1106-1109 have a length of 50 μm, a width of 8 μm, and a thickness of 0.
4 μm, 0.6 μm, 0.8 μm, and 1.0 μm, and from the upper surface of the cantilevers 1106-1109 to the lower electrode 100.
The distance to 6 was 5 μm.

Also, in this embodiment, the thin plate portion 1105
After forming the microstructure forming groove 1103 first, the microstructure forming groove 1103 is formed. After the microstructure forming groove 1103 is formed in the silicon substrate 1101, the thin plate portion 1105 is formed by thinning by etching from one side. It is also possible.

The upper electrode portion 1 of the optical deflector manufactured in this example.
When a voltage was applied between 007 and the lower electrode part 1006, displacement of the cantilever was observed with a microscope. When the amount of reflected light was measured using parallel light, it was 80% at 25V, 55% at 65V, and 3 at 30V compared to when no voltage was applied.
It became 0% and 5% at 100V.

FIG. 12 shows the microstructure shown in FIG.
FIG. 12 is a diagram showing a state of being formed into a three-dimensional array and used as an image forming mirror of a projection display device.
Reference numeral 01 is a minute structure portion, 1202 is an upper electrode portion, 1203 is a lead electrode portion, 1204 is a lower electrode portion, 1205 is a driving side substrate, 1206 is incident light, and 1207 is reflected light.

In this structure, the microstructured elements 1201 were formed in an array of 300.times.200 and were driven in a matrix by a rectangular wave of 0 to 100 V, and a projected image with good gradation was obtained.

(Embodiment 5) FIGS. 13 to 15 show a fifth embodiment of the method for producing a microstructure according to the present invention.
FIG. 13 is a diagram showing a microstructure manufactured using a silicon single crystal substrate, FIG. 14 is a manufacturing process diagram of the microstructure, and FIG. 15 is a multi-deflector of the projection type display device for the microstructure. It is a figure of an example of what was used as.

13 to 15, reference numerals 1301 to 130
Reference numeral 4 is a hinge portion, 1305 is a pedestal portion, 1307 is an upper electrode drawing portion, 1308 is a driving side substrate, 1309 is a lever portion having a light reflecting function, 1401 is a thin plate portion, 1402 is a mask portion, 1403 is a groove portion, 1404 and 1405. Indicates a hinge part.

In FIG. 13, by applying a voltage between a lower electrode (not shown) formed in the driving side substrate 1308 and an upper electrode (not shown) formed on the light reflecting portion 1309, The lever portion 1309 is connected to the hinge portion 1
It is displaced according to the thickness and width of 301 to 1304. At that time, as the applied voltage is increased, the lever portion is rotationally driven in order from 1301 having a small thickness and width until it hits the lower electrode. Therefore, by controlling the applied voltage, the displacement angle of the lever can be changed and the amount of reflected light can be controlled.

Next, referring to FIG. 14, the lever portion 130 will be described.
9, hinge portions 1301 to 1304 and pedestal portion 1305
The manufacturing method of will be described.

FIG. 14 shows a method of forming a structure in the AA ′ section of FIG. 13, and FIG. 14A shows a state in which a thin plate portion 1401 is formed from a single crystal silicon substrate by using the same method as in Example 1. Show. The groove 1403 was also formed using the same method as in Example 1. Aluminum was used as the etching mask portion 1402. 14
(B) and (c) show cantilevers 1405 to 140.
8A and 8B are views for explaining the step of forming a thickness change in FIG. 8, in which resist patterning and aluminum etching are performed for each area where the thickness is changed, and dry etching is repeated to form microstructures having different thicknesses. . FIG. 14D shows the final shape. As in Example 4, a glass layer (not shown) that functions as an insulating layer and a bonding layer on the lower surface of FIG.
Is formed to have a thickness of 0.5 μm. Further, other steps were formed by using the same method as in Example 4.

The length of the hinge portions 1405 to 1408 is 8 μm, the width and the thickness are the same, and the smaller one is 3 μm.
m, 4 μm, 5 μm, and 6 μm. Also, the lever portion 1
The size of 309 is 30 μm in length and 10 μm in width, and the distance from the upper surface of the lever portion 1309 to the lower electrode 1306 is 1
It was 5 μm.

When a voltage was applied between the upper electrode (not shown) and the lower electrode 1306 manufactured in this example, the displacement of the lever portion was observed with a microscope. When the amount of reflected light was measured using parallel light, it was 80% at 20V, 55% at 30V, and 30% at 40V compared to when no voltage was applied.
%, 5% at 80V.

FIG. 15 shows the microstructure shown in FIG.
FIG. 15 is a diagram showing a state of being formed into a three-dimensional array and used as an image forming mirror of a projection display device.
Reference numeral 01 is a light reflecting portion, 1502 is a lever portion, 1503 is an upper electrode drawing portion, 1504 is a lower electrode portion, 1505 is a driving side substrate, 1506 is incident light, and 1507 is reflected light. In this structure, the microstructure element 1001 is 640 × 480.
When they were formed into an array and were subjected to matrix driving with a rectangular wave of 0 to 100 V, a projected image with good gradation was obtained.

[0076]

As described above, by providing the thin plate portion for forming the structure and the frame body portion for holding the thin plate portion, the bending due to the residual stress during film formation and the scratches due to the handling are provided. It is possible to significantly suppress the breakage of the structure intervening with, and it is possible to dramatically improve the precision and the yield of the formation of the microstructure.

Further, in the element in which the minute structures are formed in an array, the distribution of the warp amount between the respective minute structures can be remarkably suppressed, so that the element performance can be greatly improved.

Furthermore, since the etching amount or polishing amount is smaller than that of the conventional bonding method,
The amount of etchant consumed and the contamination of the etching device are reduced, and the productivity is improved. Further, the frame portion is easy to recycle as a silicon raw material.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a cantilever structure of Example 1.

FIG. 2 is a schematic perspective view of a silicon substrate of Example 1.

FIG. 3 is a process drawing showing a manufacturing process of the cantilever structure of FIG.

FIG. 4 is a structural diagram of an AFM detection probe unit according to a second embodiment.

5A to 5C are process drawings showing a manufacturing process of the probe unit of FIG.

6 is a plan view of a probe forming mold material of the probe of FIG. 4;

7 is a cross-sectional view taken along the line A-A ′ of FIG.

FIG. 8 is a schematic perspective view of a part of a structure forming substrate used in a third embodiment.

FIG. 9 is a process drawing showing a process of manufacturing a microstructure of Example 3;

FIG. 10 is a schematic perspective view of a microstructure manufactured using a silicon single crystal substrate of Example 4.

FIG. 11 is a process chart showing a manufacturing process of the microstructure shown in FIG. 10;

12 is a schematic cross-sectional view of a multi-mirror of a projection type display device using the microstructure of FIG.

FIG. 13 is a schematic perspective view of a microstructure manufactured in Example 5 using a silicon single crystal substrate.

FIG. 14 is a process diagram showing a manufacturing process of the microstructure shown in FIG.

15 is a schematic cross-sectional view of a multi-mirror of a projection display device using the microstructure of FIG.

FIG. 16 is a process drawing showing an example of a conventional method for producing a microstructure (cantilever).

FIG. 17 is a process drawing showing another example of a conventional method for producing a microstructure (cantilever).

[Explanation of symbols]

101 cantilever part 102 pedestal part 103 structure holding substrate part 201 frame part 202 thin plate part 301 microstructure forming substrate 302 silicon nitride film 303 etching part 304 silicon (111) crystal face 305 groove part 306 structure holding substrate 307 pedestal part 308 cantilever part 309 frame part 401 lever part 402 hinge part 403 probe part 404 detection upper electrode lead part 405 contact electrode part 406 contact part 407 pedestal part 408 detection lower electrode part 409 electrostatic displacement detection circuit part 501 microstructure Body-forming substrate 502 Silicon nitride film 503 Etched portion 504 Silicon (111) crystal plane 505 Groove portion 506 Bonding upper electrode and its lead portion 507 Detection upper electrode partially used as a bonding upper electrode and its lead portion 508 Inspection Substrate on the output circuit side 509 Lower electrode for detection 510 Lower electrode for joining 511 Base part 512 Sacrificial layer 513 Contact part 514 Probe connection part 515 Probe part 601 Single crystal silicon (100) substrate 602 Probe formation groove 801 Silicon single crystal Bonding side substrate part 802 Frame part 803 Thin plate part 804 Silicon oxide part 901 (by thermal oxidation) Silicon part 902 Driving upper electrode part 903 Crimping part 904 Groove part 905 Driving side substrate 906 Lever base part 907 Driving bottom electrode 908 Connection part 909 Extraction electrode part 910 Sacrificial layer part 911 Resist 912 Probe part 1001 to 1004 Cantilever 1005 Pedestal part 1006 Lower electrode part 1007 Upper electrode part 1008 Upper electrode extraction part 1009 Driving side substrate 1101 Frame part 1102 Mask part 1103 Groove part 1104 Frame part 11 5 Thin plate part 1106 to 1109 Cantilever part 1110 Etching part 1201 Microstructure part 1202 Upper electrode part 1203 Upper electrode extraction part 1204 Lower electrode part 1205 Driving side substrate 1206 Incident light 1207 Reflected light 1301 to 1304 Hinge part 1305 Pedestal part 1307 Upper electrode Drawer 1308 Driving side substrate 1309 Lever part having light reflecting function 1401 Thin plate part 1402 Mask part 1403 Groove part 1404 Hinge part 1405 Hinge part 1501 Light reflecting part 1502 Lever part 1503 Upper electrode drawing part 1504 Lower electrode part 1505 Driving side substrate 1506 Incident Light 1507 Reflected light 1601 First substrate 1602 Sacrificial layer 1603 Cantilever portion 1604 Cantilever member 1702 Pyrex glass layer 1703 Second substrate 1704 Cantilever part 1705 Pedestal part

Claims (10)

[Claims] 1. A first etching step of removing a part of a substrate from one surface by etching to form a thin plate portion in the substrate, and a part of a surface opposite to the etching surface is removed by etching to form a microstructure. A second etching step of forming a groove in the thin plate forming portion, a step of joining the substrate subjected to the two etching steps to another substrate at the surface on which the groove for the microstructure is formed,
A method for forming a microstructure, comprising the step of removing at least a part of a thin plate portion from a substrate by etching at least a part of the thin plate portion from the surface of the substrate on which the thin plate portion has been formed by the first etching step. 2. The method according to claim 1, wherein at least a part of the substrate is made of silicon single crystal. 3. The method of claim 1 wherein at least a portion of the substrate comprises photosensitive glass. 4. The method according to claim 1, wherein at least a part of the thin plate portion is made of silicon oxide. 5. The method according to claim 1, wherein the bonding of the two substrates is anodic bonding. 6. The method according to claim 1, wherein the joining of the two substrates is a crimping of a metallic material surface. 7. A microstructure formed by the method according to claim 1. 8. An atomic force microscope in which a microstructure formed by the method according to any one of claims 1 to 6 is incorporated in a detection probe section. 9. A scanning tunneling current microscope in which a microstructure formed by the method according to claim 1 is incorporated in a probe unit. 10. An optical deflecting device in which a microstructure formed by the method according to claim 1 is incorporated in a microdeflector.