JPH09190996A - Manufacture of film structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely prevent a film and a substrate or a film and a film from sticking fast, in the case of forming a film on a substrate. SOLUTION: To begin with, a film or a film layer to serve as sacrificed material is made on a substrate. Next, this substrate or the sacrificed material is etched by etchant to form very small space between the film and the film or between the film and the substrate. Then, this etchant is cleaned and removed by cleaning solution. Next, before the above cleaning liquid existing in the very small space dries, the molten sublimate is stuck between the above film and the film or between the film and the substrate. Next, this sublimate is solidified. Then, the above sublimate is sublimed.

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 thin film structure formed by forming a thin film on a substrate.

[0002]

2. Description of the Related Art In recent years, with the development of semiconductor manufacturing technology, microstructures or micromechanical elements of micron order have been obtained by using these technologies.
Among these elements, for example, a self-supporting thin film structure, that is, a structure in which a part of the thin film floats from the substrate and is elastically supported by the substrate is an actuator (driving element), a sensor, a microgripper. (For example, JP-A-5
It is extremely useful as a structure applied to (for example, disclosed in JP-A-253870).

Conventionally, in the case of manufacturing such a thin film structure, after forming a thin film on a substrate and performing desired patterning, the substrate itself or only a sacrificial layer between the substrate and the thin film is etched with an etching solution. Among them, a method of selectively removing by etching is adopted. This etching is finished by immersing the substrate in a cleaning solution such as pure water or isopropyl alcohol, and sufficiently cleaning and removing the etching solution.

Then, the target thin film structure is obtained by lifting the substrate from the cleaning solution and drying it.

[0005]

However, in the conventional method for manufacturing a thin film structure, the etching solution is removed by a cleaning solution after forming a minute gap between the thin film and the substrate or the thin film in the etching solution. Therefore, during drying, due to the surface tension of the cleaning solution existing in the minute gap between the thin film and the substrate or between the thin film and the thin film,
There has been a problem that the thin film and the substrate or the thin film and the thin film adhere to each other.

The present invention has been made in order to solve such a conventional problem, and provides a method of manufacturing a thin film structure capable of easily and surely preventing the thin film and the substrate or the thin film and the thin film from adhering to each other. The purpose is to provide.

[0007]

According to a first aspect of the present invention, there is provided a method of manufacturing a thin film structure, which comprises a step of forming a thin film layer serving as a thin film or a sacrificial material on a substrate, and etching the substrate or the sacrificial material with an etching solution. Forming a minute gap between the thin films or between the thin film and the substrate; cleaning and removing the etching solution with a cleaning solution; and before the cleaning solution present in the minute gap is dried, It has a step of adhering a sublimable substance in a molten state between the thin films or between the thin film and the substrate, a step of solidifying the sublimable substance, and a step of sublimating the sublimable substance And

According to a second aspect of the present invention, there is provided a method of manufacturing a thin film structure, wherein a step of forming a thin film or a thin film layer serving as a sacrificial material on a substrate, and etching the substrate or the sacrificial material with an etching solution, Alternatively, a step of forming a minute gap between the thin film and the substrate, a step of washing and removing the etching solution with a washing solution, and a step of being well familiar with the washing solution and the sublimable substance before the washing solution is dried. A step of depositing a treatment solvent, a step of depositing a molten sublimable substance between the thin film and the thin film or between the thin film and the substrate before the pretreatment solvent present in the minute gap is dried, It is characterized by including a step of solidifying the sublimable substance and a step of sublimating the sublimable substance.

A method of manufacturing a thin film structure according to a third aspect is the method of manufacturing a thin film structure according to the first or second aspect, wherein sublimation of the sublimable substance is performed at atmospheric pressure. A thin film structure manufacturing method according to a fourth aspect is the thin film structure manufacturing method according to the third aspect, wherein the sublimation of the sublimable substance is performed at room temperature. A method for producing a thin film structure according to claim 5 is the method for producing a thin film structure according to any one of claims 1 to 4, wherein the temperature of the sublimable substance in the molten state is 50 ° C or higher and 220 ° C or lower. Is characterized in that.

A method of manufacturing a thin film structure according to claim 6 is the method of manufacturing a thin film structure according to any one of claims 1 to 5, wherein the sublimable substance is naphthalene or paradichlorobenzene. And Claim 7
7. The method for producing a thin film structure according to any one of claims 1 to 6, wherein the pretreatment solvent is isopropyl alcohol, methanol, ethanol, butanol, acetone, ether or cyclohexanol. It is characterized by comprising one substance selected from the following or a mixed solution thereof.

(Operation) In the method of manufacturing a thin film structure according to the first aspect, first, a thin film or a thin film layer serving as a sacrificial material is formed on a substrate. Next, the substrate or the sacrificial material is etched with an etching solution to form a minute gap between the thin films or between the thin film and the substrate.

After that, the etching solution is washed away by the cleaning solution. Next, before the cleaning solution existing in the minute gap is dried, a sublimable substance in a molten state is attached to the minute gap between the thin films or between the thin film and the substrate.

After the sublimable substance is solidified, it is sublimated as it is to obtain a predetermined thin film structure. In the method of manufacturing the thin film structure according to the second aspect, first, a thin film or a thin film layer serving as a sacrificial material is formed on the substrate. Next, the substrate or the sacrificial material is etched with an etching solution to form a minute gap between the thin films or between the thin film and the substrate.

After that, the etching solution is washed away by the cleaning solution. Next, before the cleaning solution existing in the minute gap is dried, a pretreatment solvent that is well compatible with the cleaning solution and the sublimable substance is replaced with the cleaning solution and deposited. After this, before the pretreatment solvent present in the minute gap is dried,
A sublimable substance in a molten state is attached to a minute gap between the thin films or between the thin films and the substrate.

After the sublimable substance is solidified, it is sublimated as it is to obtain a predetermined thin film structure. In the thin film structure manufacturing method of the third aspect, sublimation of the sublimable substance is performed at atmospheric pressure. In the thin film structure manufacturing method of the fourth aspect, sublimation of the sublimable substance is performed at room temperature (for example, a temperature of 10 ° C. or higher and 40 ° C. or lower).

In the method of manufacturing a thin film structure according to a fifth aspect, the temperature of the sublimable substance in a molten state is set to 50 ° C. or higher and 220 ° C. or lower. In the method of manufacturing a thin film structure according to claim 6, naphthalene or paradichlorobenzene having a relatively low melting point is used as the sublimable substance. In the method for manufacturing a thin film structure according to claim 7, the pretreatment solvent is selected from isopropyl alcohol, methanol, ethanol, butanol, acetone, ether or cyclohexanol.
Substances or mixtures thereof are used.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a flexible microgripper (Jpn.J.Appl.Phys.vol.33 pp210) manufactured according to the first embodiment of the method for manufacturing a thin film structure of the present invention.
7-2112 1994).

This flexible micro gripper is
A pair of finger portions 13 and 15 made of a silicon nitride film are formed so as to project from both surfaces of the support 11 made of silicon (Si). And a pair of finger parts 1
A minute gap 17 is formed between 3 and 15. A thin film coil 19 made of gold is formed on the finger portions 13 and 15.

The thin film coil 19 is connected to electrodes 21 made of gold and formed on both surfaces of the support 11. A holding protrusion 23 is formed at the tip of each of the finger portions 13 and 15. The flexible micro gripper described above
It is manufactured as described below by the first embodiment of the method for manufacturing a thin film structure of the present invention.

First, as shown in FIGS. 2A and 2B, a 0.7-μm thick silicon nitride film 27 is formed by LPCVD on the entire surface of both sides of the silicon substrate 25. Next, the silicon nitride film 27 is applied to the finger portion 1
3 and the support 11 are patterned. After that, the thin film coil 19 and the electrode 21 made of gold are formed by the lift-off method.

Next, the sample is immersed in an aqueous solution of potassium hydroxide (KOH), and unnecessary silicon portions of the silicon substrate 25 are removed by etching to obtain a sample as shown in (c).

After that, the sample is washed with pure water, the potassium hydroxide aqueous solution is removed, and the etching is stopped.
Next, before the pure water is dried, the sample is immersed in isopropyl alcohol, and the pure water present in the minute gap 17 between the pair of finger portions 13 and 15 is replaced with isopropyl alcohol.

After this, the sample is taken out of isopropyl alcohol and immersed in a molten naphthalene solution before being dried. The naphthalene solution is heated to a temperature slightly higher than the melting point of 80 ° C. to be in a molten state. Next, when the naphthalene solution adheres to the details of the sample, the sample is pulled up into the air at room temperature and atmospheric pressure to rapidly solidify the naphthalene.

The room temperature here means a normal room atmosphere temperature of, for example, 10 ° C. or higher and 40 ° C. or lower, and the atmospheric pressure means a pressure of about 1 atm. After that, the naphthalene adhering to the sample is removed by sublimation in air at room temperature and atmospheric pressure, and a flexible microgripper as shown in FIG. 1 is manufactured. The above steps are summarized as shown in FIG.

In the method of manufacturing the thin film structure described above, before the isopropyl alcohol existing in the minute gap 17 between the pair of finger portions 13 and 15 is dried, the molten state is maintained between the pair of finger portions 13 and 15. Since the naphthalene is adhered and the adhered naphthalene is solidified and sublimated as it is, it is possible to easily and surely prevent the pair of finger portions 13 and 15 from adhering to each other.

That is, when the pair of fingers 13 and 15 are formed in the etching solution as in the conventional case, the etching solution is removed by the cleaning solution and the cleaning solution is dried as it is, so that the space between the pair of fingers 13 and 15 is removed. Due to the surface tension of the cleaning solution present in the minute gap 17, the pair of finger portions 13 and 15 adhere to each other during drying. However, in the above-described manufacturing method, the pair of finger portions 13 and 15 are melted between the pair of finger portions 13 and 15. The naphthalene in the state is attached to remove the cleaning solution, and the attached naphthalene is allowed to coagulate and sublime as it is.
It is possible to easily and surely prevent the 3, 15 from coming into close contact with each other.

In the method of manufacturing the thin film structure described above, after the etching solution is washed away with pure water and before the pure water present in the minute gap 17 between the pair of finger portions 13 and 15 is dried, Pure water is replaced with pure water and isopropyl alcohol which is well compatible with sublimable substances to be adhered. After that, before the isopropyl alcohol present in the minute gaps 17 is dried, it is replaced with isopropyl alcohol to remove the naphthalene in a molten state. Since they are attached, naphthalene can be attached to the minute gaps 17 of the thin film structure quickly and reliably.

Further, in the above-mentioned method for manufacturing a thin film structure, since the sublimation of naphthalene is carried out at atmospheric pressure, the naphthalene can be sublimated easily and surely without forming a special pressure atmosphere. . Further, in the above-described manufacturing method, since the sublimation of naphthalene is performed at room temperature at room temperature, it is possible to easily and reliably sublimate naphthalene without forming a special temperature atmosphere.

Further, in the above-described manufacturing method, since naphthalene is melted at a relatively low temperature of about 80 ° C., naphthalene can be easily melted. Further, in the above-described method for manufacturing a thin film structure, since the sublimable substance is naphthalene having a relatively low melting point, the molten sublimable substance can be easily formed in the minute gap 17 between the pair of finger portions 13 and 15. ， It can be surely attached.

FIG. 4 shows a thin film structure manufactured by the second embodiment of the method for manufacturing a thin film structure of the present invention. In this thin film structure, a cantilever 31 made of polycrystalline silicon is provided on one surface of a support 29 made of silicon (Si).
And a doubly supported beam.

Then, the minute gaps 35 and 3 are provided between the cantilever 31 and the support 29, and between the cantilever 33 and the support 29.
7 are formed. The above-mentioned thin film structure is manufactured as described below by the second embodiment of the method for manufacturing a thin film structure of the present invention. First, as shown in FIG. 5A, a silicon oxide film to be the sacrificial layer 41 is formed on one surface of the silicon substrate 39 by sputtering and patterned.

Next, a polycrystalline silicon film 43 is formed on the outer side of the sacrificial layer 41 by the CVD method, and is patterned so that the shapes of the cantilever beam 31 and the cantilever beam 33 are obtained. After that, the sample is immersed in an aqueous solution of hydrofluoric acid (HF), the sacrificial layer 41 is removed by etching, and (c)
A sample as shown in is obtained.

After that, the sample is washed with pure water, the hydrofluoric acid aqueous solution is removed, and the etching is stopped. Next, the sample is immersed in isopropyl alcohol. After that, the sample is taken out from isopropyl alcohol and immersed in a molten naphthalene solution before being dried.

The naphthalene solution has a melting point of 80 ° C.
It is heated to a slightly higher temperature and is in a molten state.
Next, when the naphthalene solution adheres to the details of the sample, the sample is pulled up into the air at room temperature and atmospheric pressure to rapidly solidify the naphthalene. After that, the naphthalene adhering to the sample is removed by sublimation in air at room temperature and atmospheric pressure, and the cantilever beam 31 and the cantilever beam 3 as shown in FIG.
A thin film structure having 3 is produced.

In the method of manufacturing the thin film structure described above, the cantilever 31 is formed before the isopropyl alcohol existing in the minute gap 35 between the cantilever 31 and the support 29 is dried.
Since the naphthalene in a molten state is attached to the minute gap 35 between the support 29 and the support 29, the attached naphthalene is solidified and sublimated as it is, so that the cantilever 31 and the support 29 can be easily attached to each other. It can be surely prevented.

6 and 7 show a micro-electrostatic motor manufactured by the third embodiment of the method for manufacturing a thin film structure of the present invention. With this micro electrostatic motor,
A silicon nitride layer 47 is formed on one surface of a cylindrical support body 45 made of silicon (Si). The shape of the support body 45 is not limited to the cylindrical shape.

The bearing portion 4 is provided at the center of the silicon nitride layer 47.
A bearing 53, which is composed of 9 and a bearing support 51, is formed so as to project. The bearing portion 49 and the bearing support portion 51 are made of polycrystalline silicon. A rotor 55 made of polycrystalline silicon is rotatably supported on the bearing 49.

Then, the rotor 55 and the silicon nitride layer 4
A minute gap 57 is formed between the first and second electrodes. Rotor 5
On the outside of 5, a stator 59 made of polycrystalline silicon
Are formed. An aluminum electrode 61 is formed on the upper surface of the stator 59.

The above-described micro-electrostatic motor is manufactured as described below according to the third embodiment of the method for manufacturing a thin film structure of the present invention. First, as shown in FIG. 8A, a silicon nitride layer 47 is formed on one surface of the silicon substrate 63 for the purpose of electrical isolation.

Next, silicon phosphide glass (Phosphosilicate-Glass) to be the first sacrificial layer 65 is deposited and patterned by the LPCVD method. Next, as shown in (b), polycrystalline silicon 67 is deposited on the outer side of the first sacrificial layer 65 by the LPCVD method to form a rotor 55 that serves as a rotor, and a stator 59 that surrounds the rotor 55.
It is patterned so that the shape of the bearing support portion 51 is obtained.

Thereafter, as shown in FIG. 3C, a silicon phosphide glass serving as the second sacrificial layer 69 is deposited and patterned by the LPCVD method. Next, as shown in (d), the polycrystalline silicon 71 is formed outside the second sacrificial layer 69.
Are deposited by the LPCVD method and are patterned so that the shape of the bearing 49 is obtained.

After that, the sample was immersed in an aqueous solution of hydrofluoric acid,
First and second sacrificial layers 6 made of silicon phosphide glass
5,69 are removed by etching to obtain a sample as shown in (e). After that, the sample is washed with pure water, the hydrofluoric acid aqueous solution is removed, and etching is stopped.

Next, the sample is immersed in isopropyl alcohol. After that, the sample is taken out from isopropyl alcohol and immersed in a molten naphthalene solution before being dried. The naphthalene solution has a melting point of 8
It is heated to a temperature slightly higher than 0 ° C and is in a molten state.

Next, when the naphthalene solution adheres to the details of the sample, the sample is pulled up into the air at room temperature and atmospheric pressure to rapidly solidify the naphthalene. After that, the naphthalene adhering to the sample is removed by sublimation in air at room temperature and atmospheric pressure, and a micro electrostatic motor as shown in FIG. 6 is manufactured.

In the method of manufacturing a thin film structure described above, before the isopropyl alcohol existing in the minute gap 57 between the rotor 55 and the silicon nitride layer 47 is dried, the minute amount between the rotor 55 and the silicon nitride layer 47 is reduced. Molten naphthalene is attached to the gap 57, and the attached naphthalene is solidified and sublimated as it is.
It is possible to easily and surely prevent the silicon nitride layer 47 and the silicon nitride layer 47 from coming into close contact with each other.

In the embodiment described above, an example in which naphthalene is used as the sublimable substance has been described. However, the present invention is not limited to this embodiment, and the sublimable substance may be, for example, A substance as shown in can be used.

[Table 1] Among these sublimable substances, naphthalene and paradichlorobenzene have a relatively low melting point, and thus are easy to handle and have good adhesion to the minute gaps 17, 35 and 57.

Further, in the above-mentioned embodiment, an example in which pure water and isopropyl alcohol which is well compatible with the sublimable substance are used as the pretreatment solvent has been described, but the present invention is not limited to this embodiment. Not, for example,
Methanol, which is familiar to pure water and sublimable substances,
One substance selected from ethanol, butanol, acetone, ether, cyclohexanol or a mixture thereof may be used.

Furthermore, in the above-described embodiment, an example in which pure water is used as the cleaning solution has been described, but the present invention is not limited to this embodiment, and for example, an aqueous solution containing a surfactant or alcohol. Alternatively, alcohol may be used. When an alcohol such as isopropyl alcohol is used as the cleaning solution, the alcohol serves as both the cleaning solution and the pretreatment solvent, so that the sublimable substance can be directly attached without using a separate pretreatment solvent. .

[0049]

As described above, in the method of manufacturing a thin film structure according to the first aspect, before the cleaning solution existing in the minute gap between the thin films or between the thin films and the substrate is dried,
Since a sublimable substance in a molten state is attached to the minute gap and the attached sublimable substance is solidified and sublimated as it is, it is easy to adhere the thin film to the substrate or the thin film to the thin film.
It can be surely prevented.

The same effect as in claim 1 can be obtained in the method of manufacturing a thin film structure according to claim 2, but in the method of manufacturing a thin film structure according to claim 2, the etching solution is washed and removed by a cleaning solution. After that, before the cleaning solution existing in the minute gap between the thin film and the thin film or between the thin film and the substrate dries, the cleaning solution and the pretreatment solvent that is well compatible with the sublimable substance are replaced by the cleaning solution and attached. After that, before the pretreatment solvent existing in the minute gap is dried, the sublimable substance in the molten state is attached to the pretreatment solvent by replacing it with the pretreatment solvent, so that the sublimable substance is adhered to the minute gap of the thin film structure. fast,
Can be reliably attached.

In the method of manufacturing a thin film structure according to the third aspect of the invention, since the sublimation substance is sublimated at atmospheric pressure, the sublimation substance can be easily formed without forming a special pressure atmosphere.
It can surely sublime. In the method for manufacturing a thin film structure according to claim 4, since the sublimation substance is sublimated at room temperature, the sublimation substance can be easily and surely sublimated without forming a special temperature atmosphere. .

In the method for manufacturing a thin film structure according to the fifth aspect, since the temperature of the sublimable substance in a molten state is set to 50 ° C. or higher and 220 ° C. or lower, the sublimable substance can be easily and surely held at a relatively low temperature. It can be melted. In the method of manufacturing a thin film structure according to claim 6, since naphthalene or paradichlorobenzene having a relatively low melting point is used as the sublimable substance, a sublimable substance in a molten state can be easily formed between the thin film and the substrate. Can be reliably attached.

In the method for manufacturing a thin film structure according to claim 7, as the pretreatment solvent, one substance selected from isopropyl alcohol, methanol, ethanol, butanol, acetone, ether or cyclohexanol or a mixed solution thereof is used. Thus, the replacement of the cleaning solution such as pure water with the pretreatment solvent, and the replacement of the pretreatment solvent with the sublimable substance can be performed quickly and reliably.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a flexible microgripper manufactured according to a first embodiment of a method for manufacturing a thin film structure of the present invention.

FIG. 2 is an explanatory view showing a method of manufacturing the flexible micro gripper of FIG.

3A to 3C are process diagrams briefly showing a manufacturing process of the flexible micro gripper of FIG.

FIG. 4 is a perspective view showing a thin film structure having a cantilever and a cantilever manufactured by a second embodiment of the method of manufacturing a thin film structure of the present invention.

FIG. 5 is an explanatory view showing a method of manufacturing the flexible micro gripper of FIG.

FIG. 6 is a perspective view showing a micro electrostatic motor manufactured by a third embodiment of the method for manufacturing a thin film structure of the present invention.

FIG. 7 is a sectional view taken along the line − in FIG.

FIG. 8 is an explanatory diagram showing a method of manufacturing the micro electrostatic motor of FIG.

[Explanation of symbols]

 11, 29 Supporting body 13, 15 Finger part 17, 35, 57 Micro gap 31 Cantilever 41 Sacrificial layer 47 Silicon nitride layer 55 Rotor 65 First sacrificial layer 69 Second sacrificial layer

Claims (7)

[Claims] 1. A step of forming a thin film or a thin film layer serving as a sacrificial material on a substrate, and etching the substrate or the sacrificial material with an etching solution to form a minute gap between the thin films or between the thin film and the substrate. And a step of cleaning and removing the etching solution with a cleaning solution, and a molten state between the thin film and the thin film or between the thin film and the substrate before the cleaning solution existing in the minute gap is dried. And a step of solidifying the sublimable substance, and a step of sublimating the sublimable substance, the method for producing a thin film structure. 2. A step of forming a thin film or a thin film layer serving as a sacrificial material on a substrate, and etching the substrate or the sacrificial material with an etching solution to form a minute gap between the thin films or between the thin film and the substrate. A step of forming, a step of washing and removing the etching solution with a washing solution, a step of adhering a good pretreatment solvent to the washing solution and the sublimable substance before the washing solution is dried, and the minute A step of attaching a molten sublimable substance between the thin film and the thin film or between the thin film and the substrate before the pretreatment solvent present in the gap is dried, and a step of solidifying the sublimable substance, And a step of sublimating the sublimable substance. 3. The method of manufacturing a thin film structure according to claim 1, wherein the sublimation of the sublimable substance is performed under atmospheric pressure. 4. The method of manufacturing a thin film structure according to claim 3, wherein the sublimation of the sublimable substance is performed at room temperature. 5. The method of manufacturing a thin film structure according to claim 1, wherein the temperature of the sublimable substance in the molten state is 50 ° C. or higher.
A method for producing a thin film structure, which is 0 ° C. or lower. 6. The method of manufacturing a thin film structure according to claim 1, wherein the sublimable substance is naphthalene or paradichlorobenzene. 7. The method of manufacturing a thin film structure according to claim 1, wherein the pretreatment solvent is selected from isopropyl alcohol, methanol, ethanol, butanol, acetone, ether or cyclohexanol. 1. A method of manufacturing a thin film structure, comprising the substance 1 or a mixed solution thereof.