JPH09301796A - Micromachine and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of a stress gradient in a thickness direction in a structural body composed of at least two layers of partial layers and to suppress the occurrence of warpage, etc., in a cantilever, etc., as the structural body by forming at least one of the partial layer of a micromachine having the structural body described above of non-continuous layers including numerous member regions. SOLUTION: At least one layers of the partial layers of the micromachine having the structural body composed of at least two layers of the partial layers are formed of the non-continuous layers including numerous member regions. For example, the structural films of the micromachine are the continuous films 103 of polysilicon embedded with numerous silicon crystallites 102 as the numerous member regions. The formation of such structural films constituting the micromachine is executed by (a) forming a low-temp. oxide film 101 on a silicon substrate 100, (b) depositing the numerous silicon crystallites 102 as the numerous member regions on the film 101 and (c) forming the non-continuous layers consisting of the numerous silicon crystallites 102 as nucleus forming layers and forming the continuos films 103 thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micromachine having a microstructure and a method for manufacturing the same, and more particularly to a film forming technique of a polycrystalline material which constitutes a structure of the micromachine.

[0002]

2. Description of the Related Art FIG. 4 schematically shows a conventional method for manufacturing a micromachine.
This will be described with reference to FIG. For details, see the literature (Theresa A. Core, WKTsang, Steven J. Sherman, "Fabri.
cationTechnology for an Integrated Surface-Microma
chined Sensor ", Solid State Technology, October 1993,
39-47) etc.

(A) An oxide film 201 is formed on the main surface of a silicon substrate 200 by thermal oxidation, and LP-CVD is performed thereon.
Silicon nitride film 202 by (low pressure-chemical vapor deposition)
Is formed, and an LTO (low temperature oxide) film 203 is further formed thereon by CVD. The LTO film 203 is a so-called sacrificial layer (sacrificial etching is performed in the later step (d)).

(B) Dimples 204 are formed by etching to the extent that they do not penetrate the LTO film 203, and the LTO film 203, the silicon nitride film 202, and the oxide film 201 are penetrated in the area where an anchor portion described later is formed. Etching is performed to form the opening 205.

(C) A polysilicon film 206 is formed by LP-CVD and patterned into a desired shape by photolithography and etching.

(D) The LTO film 203 is subjected to sacrificial etching with hydrofluoric acid or the like to obtain a cantilever or the like as a self-standing microstructure 207.

The microstructure 2 formed as described above
Reference numeral 07 denotes a movable portion 208 and an anchor portion 209 for fixing the movable portion 208 to the silicon substrate 200 which is a support base.
It is composed of Dimple 2 of LTO film 203
A bump 210 is formed on the bottom surface of the movable portion 208, and a dimple 211 is formed on the upper surface of the movable portion 208, corresponding to the position 04. The bump 210 has an effect of reducing the contact area when the bottom surface of the movable portion 208 comes into contact with the surface of the silicon substrate 200, and thus reduces the possibility of attachment. Silicon nitride film 202
Acts as an etching stopper during sacrificial etching of the LTO film 203, but reduces the frictional force when the bottom surface of the movable portion 208 rubs against the surface of the silicon substrate 200 to reduce wear, and the movable portion 208. It also has the effect of reducing the possibility that the bottom surface of the substrate will come into contact with the surface of the silicon substrate 200 and adhere.

[0008]

When forming a microstructure such as a cantilever as described above, the distribution of internal stress in the thickness direction, that is, the presence of a stress gradient, causes the beam to warp, which is not preferable. . When forming a doubly supported beam, if the compressive stress is large, it will buckle, and if the tensile stress is large, it will crack.
A slight tensile stress is preferable from the viewpoint of tensioning the beam.

The member constituting the above-mentioned micromechanical structure is the polysilicon film 206 formed by LP-CVD.
Generally, 100% monosilane is used and 0.2-
It is performed under a reduced pressure of 1.0 Torr. Deposition rate is 1
It is from 00 to 200Å / min. The film forming temperature is 600 to
The temperature is limited to 650 ° C., and at a temperature higher than this temperature, a rough film with poor adhesion is deposited and the uniformity is lowered. At temperatures below this, the deposition rate is too slow,
Not practical. However, since such a general polysilicon film has a large compressive stress, the double-supported beam structure is buckled, which makes it difficult to form a micromachine.

To solve this problem, Guckel et al., LP-CV
A method of depositing an amorphous silicon film by D and then heat treating is proposed (H. Guckel, JJ Sniegowsk
i and TTChristenson, "Fabrication of Micromechani
cal Devices from Polysilicon Films with Smooth Sur
faces ", Sensors and Actuators, 20 (1989) 117-122). By this method, not only a film with reduced compressive stress but also a film with tensile stress can be formed by heat treatment conditions.
It is an excellent film forming method for a member that constitutes a structure of a micromachine. However, since the amorphous silicon film is formed at a temperature slightly lower than the film formation temperature of polycrystalline silicon of 580 ° C., the film formation rate is extremely slow at 50 Å / min,
There is a problem that it is difficult to form a thick film. For example, when a film is formed to have a thickness of 10 μm, it is a trial calculation that it takes 33 hours and 20 minutes to form only the film, and the productivity is low and not practical. The parameters such as the temperature at which the target amorphous silicon can be deposited and the deposition rate are highly device-dependent, and were 20 Å / min at 560 ° C. in the device of the present inventors. It is estimated that the time required for film formation only for the film formation is 83 hours and 20 minutes, and the productivity is far from reality.

On the other hand, Kirsten et al. Have proposed a method of forming a polysilicon film by an epitaxial device (M. Kirsten, B. Wenk, F. Ericson, JA Schweitz, W. Riethm.
uller, P. Lange, "Deposition of thick doped polysilic
on films with low stress in an epitaxial reacter f
or surface micromachining applications ", Thin Solid
Films 259 (1995) 181-187). In this method, 100
A nucleation layer of 0Å polysilicon is formed, and a polysilicon film is formed on the nucleation layer by using an epitaxial device at a high temperature of 1000 ° C. At this time, a film having a slight tensile stress can be obtained if the film forming condition by the epitaxial device is a reduced pressure condition, and a film having a slight compressive stress can be obtained if the film formation condition is a normal pressure condition.
For example, when trying to form a film with a thickness of 10 μm, the film forming rates are 0.55 μm / min and 0.75 μm / min, respectively.
Since it is min, it is 18 minutes 10 seconds and 13 minutes 20 seconds. Even if the film formation time of the nucleation layer of polysilicon is added, the time required for film formation does not take 40 minutes, so the productivity is extremely high. However, since the member forming the structure of the micromachine is composed of two kinds of films having different stresses, there is a problem that the beam is warped in the case of a cantilever structure, particularly in the case of a long cantilever structure. .

The present invention has been made by paying attention to such a conventional problem, and suppresses the occurrence of a stress gradient in the thickness direction of the structure, and warps the cantilever or the like as the structure. It is an object of the present invention to provide a micromachine capable of suppressing the occurrence of such problems.

It is another object of the present invention to provide a micromachine manufacturing method capable of manufacturing a micromachine having the above structure at a practical cost even when the film thickness of the structure is large. To aim.

[0014]

In order to solve the above problems, the invention of a micromachine according to claim 1 provides a micromachine having a structure composed of at least two partial layers, wherein The gist is that at least one layer is a discontinuous layer including innumerable member regions. With this configuration,
The structure does not have a laminated structure of continuous films having different stresses, and the occurrence of stress gradient in the thickness direction is suppressed.

A second aspect of the present invention provides a micromachine according to the first aspect, wherein at least one of the partial layers is a continuous film made of polycrystalline silicon. With this structure, the structure suppresses the generation of stress gradient in the thickness direction due to the combination of the continuous film and the discontinuous layer. Therefore, a single film generally has a large internal stress, but film formability and processability are high. It is possible to use a polycrystalline silicon film that is excellent in cost and is advantageous in terms of cost as a continuous film.

A third aspect of the present invention provides a micromachine according to the first aspect, wherein the member region of the discontinuous layer is made of silicon. With this configuration, the member region of the non-continuous layer is made of silicon crystallite, polycrystalline silicon, or amorphous silicon, so that the non-continuous layer serves as a nucleation layer, and a continuous film such as a polycrystalline silicon film is appropriately formed thereon. Is deposited on. After the film formation, the discontinuous layer made of silicon has a structure in which it is embedded in a continuous film of polycrystalline silicon or the like, and the generation of a stress gradient in the thickness direction is suppressed.

The micromechanical invention according to claim 4 is composed of a partial layer formed by laminating at least a continuous film and a discontinuous layer including innumerable member regions so as to suppress the generation of a stress gradient in the thickness direction. The gist is to have a structure that is With this configuration, substantially the same operation as the operation of the invention described in claim 1 can be obtained.

According to a fifth aspect of the present invention, there is provided a method for producing a micromachine having a structure having at least two partial layers, the method including the following steps. Use as a summary. (A) A first step of forming a discontinuous nucleation layer, and (b) a second step of forming a continuous film on the nucleation layer. With this configuration, by using the discontinuous layer as the nucleation layer, even if the continuous film is thick, it is possible to reliably form the film in a practical time and suppress the occurrence of stress gradient in the thickness direction. A structure with is formed.

The invention of a method for manufacturing a micromachine according to claim 6 is the method for manufacturing a micromachine according to claim 5, wherein
The gist is that the first step is a step of depositing members in an island shape. With this configuration, the number of manufacturing steps is small,
The discontinuous nucleation layer can be formed by a simple method that does not require the addition of a mask.

The invention of a method for manufacturing a micromachine according to claim 7 is the method for manufacturing a micromachine according to claim 5,
The gist is that the first step is formed by including the following steps. (A) a step of forming a continuous layer, (b) a step of processing the continuous layer into a discontinuous layer. With this configuration, I
It is possible to form a discontinuous nucleation layer by a standard process as a manufacturing process of C and the like.

The invention of a method for manufacturing a micromachine according to claim 8 is the method for manufacturing a micromachine according to claim 7,
The gist of the continuous layer is a polycrystalline silicon film, and the step of processing the continuous layer into a discontinuous layer includes the following steps. (A) a step of oxidizing the surface part of the polycrystalline silicon film to form an oxide film at a grain boundary part of the polycrystalline silicon film thicker than other parts; (b) etching back the oxide film A step of leaving an oxide film only on the grain boundary portion,
(C) a step of selectively etching the polycrystalline silicon film by using the oxide film of the grain boundary portion as a mask, (d) a discontinuous layer of polycrystalline silicon which is discretized by removing the oxide film of the grain boundary portion And the process. With this configuration, the step of forming the discontinuous nucleation layer can be performed without using a photomask even when finely processing to a grain size of polycrystalline silicon, for example, submicron. Become.

[0022]

According to the micromachine of the first aspect, at least one of the partial layers in the structure composed of at least two partial layers is a discontinuous layer including innumerable member regions. In the body, the occurrence of a stress gradient in the thickness direction can be suppressed, so that the cantilever as a structure can be prevented from warping or the like.

According to the micromachine of the second aspect, since at least one of the partial layers is a continuous film made of polycrystalline silicon, the structure has a film forming property even when the film thickness is large. The workability is excellent, and the cost can be reduced.

According to the micromachine of claim 3, since the member region of the discontinuous layer is made of silicon,
The discontinuous layer serves as a nucleation layer, and a continuous film such as a polycrystalline silicon film can be appropriately formed thereon. After film formation,
The discontinuous layer made of silicon has a structure in which it is embedded in a continuous film of polycrystalline silicon or the like, and the occurrence of a stress gradient in the thickness direction is suppressed, and the same effect as the effect of the invention according to claim 1 is obtained. To be

According to a fourth aspect of the micromachine, at least a continuous film and a discontinuous layer including innumerable member regions are laminated to form a partial layer so as to suppress the occurrence of a stress gradient in the thickness direction. Since the structure described above is provided, the same effects as the effects of the invention according to claim 1 can be obtained.

According to the method of manufacturing a micromachine according to claim 5, in the method of manufacturing a micromachine having a structure composed of at least two partial layers, (a) a discontinuous nucleation layer is formed. Since the first step and (b) the second step of forming a continuous film on the nucleation layer is formed, the discontinuous layer is used as the nucleation layer. Even if the film is thick, it can be reliably formed in a practical time, and a micromachine having a structure in which the occurrence of stress gradient in the thickness direction is suppressed, Even if it is thick, it can be provided at a practical cost.

According to the micromachine manufacturing method of the sixth aspect, since the first step is a step of depositing members in an island shape, discontinuous nucleation is performed by a simple method without the need for adding a mask. Layers can be formed and manufacturing costs can be kept low.

According to the method of manufacturing a micromachine of claim 7, the first step is (a) a step of forming a continuous layer,
(B) Since the continuous layer is formed by including each step of processing into a discontinuous layer, the discontinuous nucleation layer can be formed by a standard process as a manufacturing process of IC and the like. This eliminates the need for special process development and condition setting,
Development costs can be kept low.

According to the micromachine manufacturing method of the present invention, the continuous layer is a polycrystalline silicon film, and the step of processing the continuous layer into a discontinuous layer includes (a) a surface of the polycrystalline silicon film. Part of the polycrystalline silicon film is oxidized to form an oxide film in the grain boundary part of the polycrystalline silicon film thicker than other parts, (b) the oxide film is etched back to leave the oxide film only in the grain boundary part. A step of (c) selectively etching the polycrystalline silicon film using the oxide film of the grain boundary portion as a mask; and (d) removing the oxide film of the grain boundary portion from non-discrete polycrystalline silicon. Since the step of forming a continuous layer is performed by including each step, the step of forming a non-continuous nucleation layer is a case where fine processing is performed to a grain size of polycrystalline silicon, for example, submicron. Even without a photomask Tree, it is possible to reduce the capital expenditures without the need for a high price exposure apparatus with a high degree of accuracy.

[0030]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a first embodiment of the present invention. Here, only the method for forming the structural film that constitutes the micromachine will be described.

(A) An LTO film 101 having a thickness of 1 μm is formed on the main surface of the silicon substrate 100 by a method such as thermal oxidation.

(B) Innumerable island-shaped silicon crystallites 102 are deposited on the LTO film 101. As deposition conditions,
At 1000 ° C., the hydrogen chloride gas partial pressure and the silane gas partial pressure were 7.2 × 10 ⁻³ bar and 7.3 × 10 ⁻⁴ bar, respectively.
Is supplied for 10 seconds, the silicon crystallites 102 having a diameter of 1000 to several thousand Å have an areal density of about 104 to 103 / c.
It is formed into a micro island shape with m ² (details are described in Japanese Patent Application No. 63-74755).

(C) A discontinuous layer composed of innumerable silicon crystallites 102 was used as a nucleation layer, and dichlorsilane was used thereon with an epitaxial growth apparatus at 1080 ° C.
Then, a polysilicon film 103 having a thickness of 10 μm is formed.
The deposition rate was 0.35 μm / min, and the film formation time was about 29 minutes. The formed polysilicon film 103 is
The stress was so low that it was difficult to evaluate by laser Raman spectroscopy or X-ray diffraction. The micromechanical structure film according to the present embodiment has innumerable silicon crystallites 10 as innumerable member regions.
2 is a continuous polysilicon film 103 in which
There was no stress gradient, and there was no warpage even when a cantilever was formed.

According to the method of forming a structure film constituting the micromachine of the present embodiment, the structure film having a stress gradient suppressed as described above can be used in a practical period of time even if the film thickness is large. It is possible to form a film by the method described above, and therefore, it is possible to obtain a common effect in each of the embodiments that a micromachine having a thick structure film can be provided at a practical cost. In addition to this common effect, it is a simple method that requires a small number of manufacturing steps and does not require the addition of a mask. Therefore, a unique effect that the manufacturing cost can be kept low can be obtained.

A second embodiment of the present invention will be described with reference to FIG. Here, as in the first embodiment, only the method for forming the structural film that constitutes the micromachine will be described.

(A) An LTO film 101 having a thickness of 1 μm is formed on the main surface of the silicon substrate 100 by a method such as thermal oxidation.

(B) LP-CVD is performed on the LTO film 101.
With the apparatus, a polysilicon film 110 having a thickness of 1000Å is formed as a continuous layer at 620 ° C. Deposition rate is 60Å
/ Min, and the film formation time was about 17 minutes.

(C) The polysilicon film 110 is patterned into a 1 μm square island-shaped polysilicon film 110a to form a discontinuous layer.

(D) The island-shaped polysilicon film 110a is used as a nucleation layer, and the nucleation layer is formed thereon by an epitaxial growth apparatus.
Using dichlorsilane, the thickness is 10 μm at 1080 ° C.
Then, a polysilicon film 111 is formed. Deposition rate is 0.3
It was 5 μm / min and the film formation time was about 29 minutes.
The formed polysilicon film 111 had low stress so that it was difficult to evaluate by laser Raman spectroscopy or X-ray diffractometry, as in the first embodiment. The structure film of the micromachine according to the present embodiment is a polysilicon continuous film 111 in which an innumerable 1 μm square island-shaped polysilicon film 110a as an innumerable member region is embedded, and has no stress gradient and has a cantilever structure. It did not warp when it was formed.

According to the method of forming the structure film that constitutes the micromachine of the present embodiment, in addition to the common effects described in the first embodiment, a standard manufacturing process for ICs and LSIs is further provided. Since it is composed of only such processes, there is no need to develop a special process or condition setting, so that the unique effect that the development cost can be kept low can be obtained.

A third embodiment of the present invention will be described with reference to FIG. Here, similarly to the first and second embodiments, only the method of forming the structural film that constitutes the micromachine will be described.

(A) An LTO film 101 having a thickness of 1 μm is formed on the main surface of the silicon substrate 100 by a method such as thermal oxidation.

(B) LP-CVD is performed on the LTO film 101.
With the apparatus, a 3000 Å thick polysilicon film 120 is formed as a continuous layer at 620 ° C. Deposition rate is 60Å
/ Min, and the film formation time was about 50 minutes. 121
Is a grain boundary.

(C) The polysilicon film 120 is thermally oxidized,
An oxide film 122 having a thickness of 1000Å is formed. Grain boundary 121
Since the thermal oxidation rate is high, the oxide film 122 at the grain boundary portion is formed thick.

(D) The oxide film 122 is etched back by 1000Å. 122a is an oxide film left only at the grain boundary portion.

(E) Oxide film 122a remaining only at the grain boundary portion
When the polysilicon film 120 is trench-etched by using as a mask, polysilicon 120a which is discrete to the grain size of the polysilicon film 120 is obtained.

(F) The oxide film 122a remaining only on the grain boundary portion at the top of the polysilicon 120a is dissolved and removed with dilute hydrofluoric acid to form a discontinuous layer of the polysilicon 120a.

(G) Polysilicon 120a, which is discretized to have a grain size, is used as a nucleation layer, and dichlorosilane is used on the nucleation layer by an epitaxial growth apparatus at 1080 ° C.
Then, a polysilicon film 123 having a thickness of 10 μm is formed.
The deposition rate was 0.35 μm / min, and the film formation time was about 29 minutes. The formed polysilicon film 123 is
Similar to the first and second embodiments, the stress was so low that it was difficult to evaluate by laser Raman spectroscopy or X-ray diffraction. The structure film of the micromachine according to the present embodiment is formed of the polysilicon 120a which is discretely divided into particles each having an infinite number of member regions.
Was a continuous film 123 of polysilicon in which was embedded, there was no stress gradient, and even if a cantilever was formed, it did not warp.

According to the method of forming the structure film which constitutes the micromachine of the present embodiment, in addition to the common effects described in the first embodiment, the grain size of polysilicon, for example, submicron. Even if it is a minute process, it can be performed without using a photomask. Therefore, there is no need for a high-precision and high-priced exposure device, and there is a unique effect that the capital investment can be kept low. To be

In the above description of the first to third embodiments, specific examples have been used for explanation, but the present invention is not limited to these words and drawings. An example will be described below.

As the gas species for forming the polysilicon films 103, 111, 123, dichlorosilane has been described as an example, but the invention is not limited to this, and monosilane or trichlorosilane may be used. The apparatus is not limited to the epitaxial growth apparatus, and either normal pressure or reduced pressure may be used. The film forming temperature is not limited to 1000 ° C., and may be sufficiently higher than the film forming temperature (600 to 650 ° C.) of polysilicon by LP-CVD.
The temperature is actually 800 to 1200 ° C. due to a device problem and the like. The film thickness is not limited to 10 μm and may be a thinner film or a thicker film. Since it is necessary to pattern by a method such as trench etching, it is practically 30 μm due to the problem of the capability of the etching equipment.
It is a degree. 10 if there is a better patterning method
The thickness may be increased to 0 μm or 200 μm.

As the so-called sacrifice layer, the LTO film has been described as an example, but the present invention is not limited to this, and various oxide films such as a thermal oxide film and a PSG (phosphorus glass) film can be used. In some cases, an insulating film such as a silicon nitride film or a metal such as platinum may be used. in this case,
Hot phosphoric acid, aqua regia, or the like may be used as a chemical for sacrificial etching the sacrificial layer.

Although only the method of forming the structure film constituting the micromachine has been described, the polysilicon films 103 and 11 are described.
It goes without saying that other steps such as flattening the surface by a method such as polishing may be added after depositing 1,123. The structure film is also a polysilicon film 103, 111,
Although only 123 has been described as an example, other structural films may be added. The structural material is not limited to polysilicon, and for example, polysilicon may be silicided or, in some cases, other semiconductor material such as gallium arsenide.

In the first embodiment, an example of depositing an infinite number of island-shaped silicon crystallites as the nucleation layer under the above described conditions has been described, but the present invention is not limited to this. However, it is sufficient if the conditions are island-like and innumerable silicon crystallites can be deposited. As the deposition method, vapor deposition or sputtering may be used instead of LP-CVD. The material is not limited to silicon crystallites, and may be any discontinuous material layer that acts as a nucleation layer for depositing the polysilicon film in the step of FIG. 1C.

In the second embodiment, an example in which the polysilicon film as the nucleation layer is patterned into islands has been described. However, the remaining portion of the polysilicon film 110 is island-shaped, and the portion to be removed is island-shaped. It may be a shape. In this case, the polysilicon film 110 is patterned in a net shape (the sectional views are the same). The patterned nucleation layer is not limited to polysilicon, but may be amorphous silicon or any material layer that acts as a nucleation layer for depositing a polysilicon film. As the deposition method, vapor deposition or sputtering may be used instead of LP-CVD. The film thickness is not limited, either.

In the third embodiment, an example in which an oxide film is left only at the grain boundary portion of the polysilicon film and the polysilicon film is processed into an island shape using the oxide film as a mask has been described, but the present invention is not limited to this. However, grain boundary etching in which only grain boundaries are rapidly etched may be used, and any method capable of processing a discontinuous nucleation layer may be used. As for the deposition method, in addition to LP-CVD,
Vapor deposition or sputtering may be used. The film thickness is not limited, either.

[Brief description of drawings]

FIG. 1 is a process drawing showing a first embodiment of a method for manufacturing a micromachine according to the present invention.

FIG. 2 is a process drawing showing a second embodiment of the present invention.

FIG. 3 is a process chart showing a third embodiment of the present invention.

FIG. 4 is a process diagram showing a conventional method for manufacturing a micromachine.

[Explanation of symbols]

101 LTO film 102 Silicon crystallites 103, 111, 123 forming a discontinuous layer Polysilicon film (continuous film) 110, 120 Polysilicon film as a continuous layer 110a Island-like polysilicon film forming a discontinuous layer 120a Discontinuous Discretized polysilicon forming layers

Claims (8)

[Claims] 1. A micromachine having a structure composed of at least two partial layers, wherein at least one of the partial layers is a discontinuous layer including innumerable member regions. 2. The micromachine according to claim 1, wherein at least one of the partial layers is a continuous film made of polycrystalline silicon. 3. The micromachine according to claim 1, wherein the member region of the discontinuous layer is made of silicon. 4. A structure comprising at least a continuous film and a partial layer formed by laminating a discontinuous layer including innumerable member regions so as to suppress the occurrence of a stress gradient in the thickness direction. And a micromachine. 5. A method for manufacturing a micromachine having a structure composed of at least two partial layers, which is formed by including the following steps. (A) a first step of forming a discontinuous nucleation layer, (b) a second step of forming a continuous film on the nucleation layer. 6. The method of manufacturing a micromachine according to claim 5, wherein the first step is a step of depositing members in an island shape. 7. The method of manufacturing a micromachine according to claim 5, wherein the first step is formed by including the following steps. (A) a step of forming a continuous layer, (b) a step of processing the continuous layer into a discontinuous layer. 8. The method for manufacturing a micromachine according to claim 7, wherein the continuous layer is a polycrystalline silicon film, and the step of processing the continuous layer into a discontinuous layer includes the following steps. A method for manufacturing a micromachine characterized by the above. (A) a step of oxidizing the surface part of the polycrystalline silicon film to form an oxide film at a grain boundary part of the polycrystalline silicon film thicker than other parts; (b) etching back the oxide film Leaving an oxide film only on the grain boundary portion, (c) selectively etching the polycrystalline silicon film using the oxide film on the grain boundary portion as a mask, (d) removing the oxide film on the grain boundary portion A step of forming a discontinuous layer made of discretized polycrystalline silicon.