JP3216065B2 - Method for manufacturing hollow structure - Google Patents

Abstract

PURPOSE: To make it possible to remove even extremely thin low melting org. matter layers which are sacrificial layers by dry etching by removing part of the low melting org. matter layers between substrates to form hollow parts and using the low melting org. matter layers made to remain as spacers. CONSTITUTION: An Si substrate (100) 1 is subjected to anisotropic etching, by which groove parts 2 are formed and simultaneously, the thin sheet points at the bottoms of these groove parts 2 are formed as vibratable Si membranes 3. Next, Langmuir-Blodgett (LB) films 4 as the low melting org. matter are formed as the spacers on the surfaces formed with the groove parts 2 of the substrate l and Al films which are the metallic membranes 6 are formed thereon. The LB films 4 are then irradiated with the laser beam transmitted through the substrate 1 via a mask in a vacuum atmosphere, by which the LB films 4 are decomposed and evaporated to form gap parts (hollow parts) 5. Then, the gap parts 5 are formable extremely thin if the LB films formable by monomolecule layer each are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a hollow structure, and more particularly to a method for manufacturing a hollow structure having a hollow portion in a part between a plurality of substrates separated by a spacer. >

[0002]

2. Description of the Related Art Conventionally, a hollow structure is generally known as Japanese Patent Publication 5-54.
No. 709, etc., leaving a portion to be a sacrificial layer in advance, further forming a film having a hole on the sacrificial layer, and then flowing an etching liquid through the hole. The sacrificial layer is entirely removed to form a hollow portion.

[0003]

However, in the above-mentioned prior art, the sacrificial layer is etched while the etching liquid is flowing from the hole of the film, so that there are the following problems. That is, (1) Since the etching liquid flows through the holes of the membrane, when the holes are small, surface tension acts to make it difficult for the etching liquid to enter. (2) Since the etching liquid is used for etching the sacrificial layer, the film sticks due to the surface tension of the etching liquid after the etching. (3) Since an etching liquid is used, it is difficult to form a hollow structure by etching a very thin sacrificial layer due to generation of surface tension of the etching liquid. (4) In the same sacrificial layer, it is difficult to divide into two parts: a part that needs to be etched and a part that must not be etched (a part that serves as a bonding layer).

[0004]

The hollow structure of the present invention is manufactured.
The method is to form a first thin film made of a low melting point organic substance on a substrate.
Forming and forming a second thin film on the first thin film
And after forming the second thin film, the substrate is
And irradiates a part of the first thin film with laser light through the first thin film.
Work to form a hollow part by partially removing the film
And the remainder of the first thin film not removed
Is used as a spacer, and the second thin film is hollow on the substrate.
Manufacturing a structure supported across the part
You.

[0005]

In the present application, a plurality of substrates separated by a spacer means a substrate and a substrate via a spacer, a substrate and a laminated film via a spacer, a laminated film and a laminated film via a spacer, and the like. Shall also be included.

[0007]

According to the present invention, a hollow portion is formed by removing a part of the low melting point organic material layer between the substrates, and the remaining low melting point organic material layer is used as a spacer.

The low-melting-point organic material layer may be any material that can be vaporized and evaporated by applying energy. For example, when the hollow portion is thin, it is possible to form a single molecular layer.
The use of the B film makes it possible to control the film at the molecular level.

As a means for applying energy to a part of the low melting point organic layer, for example, a laser beam can be used. As the laser light, a laser light having a wavelength in the range of 0.2 μm to 12 μm can be used. As a laser light source having such a wavelength, a CO ₂ laser, a YAG laser, an excimer laser, or the like can be used.

[0010]

[Example 1]

1, FIGS. 2-5 show a first embodiment of a hollow structure produced by the present invention, FIG. 1 is a perspective view showing the configuration of <br/> hollow structure produced by the present invention Yes, and FIGS.
It is sectional drawing showing the manufacturing method of this invention . 1 to 5, reference numeral 1 denotes a substrate which is a Si substrate (100);
Is a groove of the substrate formed by anisotropically etching the substrate 1, 3 is a groove formed by forming the groove 2 of the substrate 1, and is a Si membrane of the substrate 1, and 4 is a film formed on the substrate 1. LB film (Langmuir-Bed Rojetto film) 5 and the void portion of the was removed by Etchiingu as a sacrificial layer a part of the LB film 4 (hollow portion), the 6 LB
A metal membrane 8 formed on the film 4 by forming an Al (aluminum) film; 8, a mask for forming a gap 5 in the LB film 4; 9, a laser beam for optically etching the LB film 4; A power source for applying an electric field between the metal membrane 6 and the Si membrane 3 of the substrate 1;
Is an electrode provided at the end of the metal membrane 6, and 13 is an electrode 1
A lead wire 15 electrically connects the power supply 1 to the power supply 10 and the substrate 1 to the power supply 10. A lead 15 connects the vibration part (Si membrane) 3 and the vibration part (metal membrane) 6 of the substrate 1 by the power supply 10. This is a sound wave generated from vibration due to electrostatic attraction generated by applying an alternating electric field therebetween.

Next, a manufacturing process until the above-mentioned structure is formed will be described with reference to FIGS. First,
A groove 2 is formed on a substrate 1 made of a (100) Si substrate by anisotropic etching using KOH, and at the same time, a thin membrane portion 3 at the bottom of the groove 2 can vibrate.
(FIG. 2). Next, as shown in FIG.
An LB film 4 is formed to an arbitrary thickness on one surface on the side where
Further, an Al film to be the metal membrane 6 is formed on the LB film 4 (FIG. 4). Then, as shown in FIG. 5, the LB film 4 is decomposed by irradiating the LB film 4 with a laser beam 9 transmitted through the substrate 1 through the mask 8 in a vacuum atmosphere (not shown), and the LB film is evaporated to form a void portion. 5 is formed. Where Si
The gap between the membrane 3 and the metal membrane 6 is LB
It is the same as the film thickness of the film 4, and the smaller the thickness of the LB film 4, the smaller. Therefore, when the LB film 4 is formed to be extremely thin, the gap 5 becomes extremely narrow. Therefore, if a voltage is applied between the metal membrane 6 and the Si substrate membrane 3, the metal membrane 6 and the Si substrate membrane 3 can be attracted to each other by electrostatic attraction with a smaller voltage. Now, as shown in FIG. 1, a power supply 10 for generating an alternating voltage is connected to a metal membrane 6 and a Si membrane 3.
In this case, the metal membrane 6 and the Si membrane 3 vibrate in synchronization with the frequency of the power supply 6, and generate a sound wave 15 as a result.

The LB film 4 used in this experiment was C-22.
(Behenic acid), and 30 layers are laminated. or,
The laser beam 9 uses a CO ₂ laser, and the mask 8 is made of metal. Then, as shown in FIG. 5, the laser beam 9 passes through the hole of the mask 8, but is reflected by the other mask 8 portions.

Now, P
eak to Peak voltage 10V, frequency 10kHz
Was applied, the Si membrane 3 and the metal membrane 6 vibrated with each other to generate a sound wave.

The LB film is a straight-chain saturated fatty acid, but other LB films such as a ferroelectric LB film (for example, a diacetylene-based or benzene derivative) or a polyimide LB film can also be used. . [Embodiment 2] FIGS. 6, 7 to 11 show a second embodiment of the hollow structure of the present invention, and FIG. 6 is a perspective view showing the structure of the hollow structure of the present invention. FIG. 11 is a sectional view showing the manufacturing method.

6 to 11, reference numeral 1 denotes a substrate which is a Si substrate, 2 denotes a groove of the substrate formed by anisotropically etching the substrate 1, and 3 denotes a groove of the substrate 1.
Formed on the substrate 1, and
4 is an LB film formed on the substrate 1 and 5 is an LB film.
A void portion (hollow portion) where a part of the film 4 is removed by etching as a sacrificial layer,
An adhesive intermediate layer formed by deposition of (aluminum),
Reference numeral 7 denotes a pedestal made of glass bonded to the bonding intermediate layer 6 by anodic bonding, 8 denotes a mask for forming the voids 5 in the LB film 4, 9 denotes a laser beam for optically etching the LB film 4, and 10 denotes a laser beam. Adhesive intermediate layer 6 and Si membrane 3 of substrate 1
A high-frequency alternating voltage is generated at which the Si membrane 3 is not deformed by electrostatic attraction, and a change in the gap of the void 5 due to an external pressure acting on the Si membrane 3, that is, a change in capacitance is caused by a current change. A power supply 11 acts as follows, 11 is an electrode of the substrate 1 electrically connected to the Si membrane 3, and 12 is a voltage signal indicating a change in capacitance between the Si membrane and the adhesive intermediate layer 6 acting as an electrode. Is an electrode 11 and a power supply 10, an adhesive intermediate layer 6, an electric resistance 12, and an electric resistance 12.
A lead wire for electrically connecting each of the power supply 10 and the power supply 10, a signal extraction portion 14 from the electric resistance 12,
Reference numeral 16 denotes a pressure wave acting on the Si membrane 3.

Next, a manufacturing process until the above-mentioned structure is formed will be described with reference to FIGS. First, a groove 2 is formed on a substrate 1 made of a (100) Si substrate by anisotropic etching using a KOH solution.
At the same time, the thin portion at the bottom of the groove 2 is made into a vibrable Si membrane 3 (FIG. 7). Next, as shown in FIG. 8, an LB film 4 is formed to an arbitrary thickness on the surface opposite to the side where the groove 2 of the substrate 1 is formed.
1 film is formed (FIG. 9). Then, the adhesive intermediate layer 6 has P
Yrex glass (Corning's trademark, # 7740) is adhered by light irradiation anodic bonding (FIG. 10), and then, in a vacuum atmosphere (not shown) as shown in FIG.
The laser light 9 transmitted through the Si membrane 3 through the LB
By irradiating the film 4, the LB film is decomposed and evaporated to form the voids 5. Here, the gap between the Si membrane 3 and the metal membrane 6 is the same as the thickness of the LB film 4, and becomes smaller as the thickness of the LB film is reduced.
Therefore, when the LB film 4 is formed to be extremely thin, the gap 5 becomes extremely narrow. Therefore, when the pressure wave 16 acts on the Si membrane 3, the rate of change in the distance between the Si membrane 3 and the bonding intermediate layer 6 increases, and as a result, the distance between the Si membrane 3 and the bonding intermediate layer 6 increases. The change amount of the electric capacity becomes large. Now, as shown in FIG. 6, while applying a high frequency from the power source 10 between the Si membrane 3 and the adhesive intermediate layer 6 and simultaneously applying a pressure wave 16 to the Si membrane 3, a voltage change occurs in the signal extracting portion 14. Occurred.

The LB film used in the present invention is C-20 (arachidic acid), and is a laminate of 30 layers. or,
The laser beam 9 uses a CO ₂ laser, and the mask 8 is made of metal. In addition, the same effect as described above also occurs when the YAG laser light and the excimer laser light are used instead of the CO ₂ laser light.

The same effect as described above was obtained when a vapor deposition film of parylene was used instead of the LB film.
Therefore, the present invention does not change even when a vapor-deposited organic material such as parylene is formed and an evaporable organic material is used in addition to the LB film.

[0019]

As described above, according to the present invention,
A hollow structure having a thin hollow portion can be provided by removing a part of the low-melting-point organic material layer between the substrates to form a hollow portion and using the remaining low-melting-point organic material layer as a spacer. Even when the thickness of the low-melting organic layer serving as a sacrifice layer is extremely small, the sacrifice layer can be decomposed and then evaporated and disappeared, that is, the sacrifice layer can be removed by dry etching.

When a laminated LB film having a thickness of a single molecule, that is, a film thickness controllable on the order of the atomic length is used as the low-melting-point organic material layer, a gap (hollow portion) between substrates, for example, The gap generated between the substrate and the metal film can be controlled on the order of Angstrom length. When an ultra-thin LB film is used, a hollow structure having an ultra-thin space at any position can be manufactured. As a result, in a micro machine using electrostatic attraction, it is easy to manufacture a device that can be driven at a low voltage, and it is also possible to manufacture a device using a capacitance that changes due to minute displacement. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a sound wave generator embodying the present invention.

FIG. 2 is a manufacturing process diagram of the sound wave generator of FIG.

FIG. 3 is a manufacturing process diagram of the sound wave generator of FIG. 1;

FIG. 4 is a manufacturing process diagram of the sound wave generator of FIG. 1;

FIG. 5 is a manufacturing process diagram of the sound wave generator of FIG. 1;

FIG. 6 is a schematic diagram of a sound pressure sensor embodying the present invention.

FIG. 7 is a manufacturing process diagram of the sound pressure sensor of FIG. 6;

FIG. 8 is a manufacturing process diagram of the sound pressure sensor of FIG. 6;

FIG. 9 is a manufacturing process diagram of the sound pressure sensor of FIG. 6;

FIG. 10 is a manufacturing process diagram of the sound pressure sensor of FIG. 6;

FIG. 11 is a manufacturing process diagram of the sound pressure sensor of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Groove of substrate 3 Si membrane 4 LB film 5 Air gap 6 Metal membrane or adhesive intermediate layer 7 Pedestal 8 Mask 9 Laser beam 10 Power supply 11 Electrode 12 Electrical resistance 13 Lead wire 14 Signal extraction section 15 Sound wave 16 Pressure wave

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI H04R 31/00 G10K 9/12 101C (58) Field surveyed (Int.Cl. ⁷ , DB name) G10K 9/122 B05D 1 / 20 B23K 26/00 G01L 9/04 101 H01L 29/84 H04R 31/00

Claims (6)

(57) [Claims] A first thin film made of a low-melting organic material on a substrate;
Forming a film, and forming a second thin film on the first thin film.
Forming, and after forming the second thin film, the substrate
A part of the first thin film is irradiated with laser light through the plate,
To form a hollow part by partially removing the thin film of
And removing the first thin film that has not been removed.
The second thin film is formed on the substrate by using the remaining portion as a spacer.
It is characterized by manufacturing a structure supported by a hollow part.
A method for producing a hollow structure. 2. The method according to claim 1, further comprising :
Providing a groove in the portion of the substrate to be irradiated with laser light
The method for producing a hollow structure according to claim 1, comprising: 3. The method according to claim 1, wherein the first thin film is a Langmuir block.
3. The hollow structure according to claim 1, comprising a jet membrane.
Manufacturing method. Wherein said Langmuir-Bed Rojetto film,
4. The hollow structure according to claim 3, formed from a linear saturated fatty acid.
How to make the body. Wavelength of claim 5 wherein said laser beam, 0.2Myuemu～1
5. The method according to claim 1, wherein the thickness is in a range of 2 μm.
Manufacturing method of the above-mentioned hollow structure. Wherein said laser beam is one emitted CO ₂ laser, YAG laser, from any of the excimer laser
A hollow structure according to any one of claims 1 to 5.
Construction method.