JP3200857B2 - Manufacturing method of micromachine - Google Patents

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 micromachine having a sliding portion such as a rotor.

[0002]

2. Description of the Related Art Recently, attention has been paid to formation of minute mechanisms called micromachines or micromechanics.

[0003] For example, "Electronic Journal" (J. IEEE Japan)
An) Vol. 110, No. 4 (Heisei 2), pp. 289-296, describes micromechatronics, a technology for manufacturing micro-mechanical systems that form mechanical parts and electrostatic motors on the order of μm using IC manufacturing processes. The description has been made. In addition, Monthly Semiconductor W
orld, 1990 No. 8 on pages 60-62, S
A micromachine technology such as an electrostatic motor using an integrated circuit manufacturing process such as an i-wafer process is described. Also, NIKKEI ELECTRONICS
In the August 21, 1989 issue (Nikkei McGraw-Hill),
Special attention is given to silicon micromachines such as silicon actuators such as silicon motors.

FIG. 25 to FIG. 30 show a process of manufacturing a rotating portion of a micromachine, for example, an electrostatic Si motor.

That is, as shown in FIG. 25, first, a polycrystalline silicon film 2 is deposited on a silicon substrate 1 by a CVD method. Next, as shown in FIG. 26, the polycrystalline silicon axis 2a serving as the rotor axis is patterned using lithography technology. Next, as shown in FIG.
An O ₂ thin film 3 is deposited by a CVD method. Then, FIG.
As shown in FIG. 8, a polycrystalline silicon film 4 is deposited on the SiO ₂ thin film 3 so as to have the same thickness as the desired rotor.
Next, as shown in FIG. 29, the polycrystalline silicon film 4 is patterned by lithography to form a rotating rotor 4A. Then, as shown in FIG. 30, the SiO ₂ thin film 3 is selectively (wet) etched with, for example, diluted hydrofluoric acid to separate the rotating rotor 4A from the polycrystalline silicon shaft 2a and rotate the rotating rotor 4A. I do.

As described in the above documents,
The ultra-small mechanism described above is a very remarkable technology, and its importance is expected to become extremely large in the future.

[0007]

However, there are still many problems to be solved in the formation of such a minute micromachine.

For example, in the case where a mechanism of several μm to several hundred μm is to be formed by applying the LSI manufacturing technology by the Si micromachining technology, if it is so small, there is actually no good bearing. For this reason, the problem that friction is large, energy loss is increased, and the problem of seizure or breakage cannot be solved, and the response speed also decreases.

That is, with respect to bearings and bearings, which are sliding portions of the micromachine, friction occurs between the rotating rotor 4A and the polycrystalline silicon shaft 3 as shown in FIG. 31, for example, and the above-mentioned problem cannot be avoided. .

Further, even if a micromachine with a rotor having a small friction is to be formed, it is required to form the micromachine with a fine structure of the order of μm to several hundreds of μm and to surely exhibit a mechanical action. Processing and forming are not easy.

The present invention has been made in consideration of such conventional problems, and has high durability of a sliding portion.
Moreover, a micromachine capable of smooth sliding is obtained.

[0012]

Accordingly, the present invention provides a method of manufacturing a micromachine using silicon, comprising the steps of forming a columnar silicon axis on a silicon substrate, and forming a diamond on the entire surface of the silicon substrate and the silicon axis. forming a film to form a round <br/> rolling rotor of polysilicon around the silicon shaft by depositing an insulating film on the diamond film, and the removed the insulating film A method of solving the problem includes a step of separating the silicon shaft and the rotating rotor to make the rotor rotatable.

[0013]

By using a high melting point metal or carbon for the sliding portion, the abrasion resistance is enhanced and the sliding can be smoothly performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a micromachine according to the present invention will be described based on an embodiment shown in the drawings, applied to an electrostatic motor having a rotating rotor as a sliding portion.

(First Embodiment) FIGS. 1 to 6 are sectional views showing respective manufacturing steps of a first embodiment of the present invention.

First, in this embodiment, as shown in FIG. 1, a polycrystalline silicon film 2 is deposited on a silicon substrate 1 by a CVD method and then patterned by a lithography method to form a columnar polycrystalline silicon shaft 2a. To form

[0017] Next, as shown in FIG. 2, SiO ₂ on the entire surface
A thin film 3 is deposited by a CVD method. Further, as shown in FIG. 3, a polycrystalline silicon film 4 is formed on the SiO ₂ thin film 3.
Is deposited to a desired thickness by a CVD method, and then, as shown in FIG. 4, the polycrystalline silicon film 4 is patterned by a lithography method to form a rotating rotor 4A.

Next, as shown in FIG. 5, the rotating rotor 4A formed of polycrystalline silicon is replaced with tungsten by using a Si reduction method. In this case, the following reaction is caused by using tungsten hexafluoride (WF ₆ ).

2WF ₆ + 3Si → 2W + 3SiF ₄ ↑ Then, as shown in FIG. 6, the SiO ₂ thin film 3 is selectively etched with dilute hydrofluoric acid to form a polycrystalline silicon shaft 2a and a tungsten rotor 4A. Is separated, and the rotating rotor 4A becomes rotatable.

Since the rotating rotor 4A is made of tungsten in this way, its durability can be more than doubled as compared with the conventional rotating rotor made of polycrystalline silicon.

Second Embodiment FIGS. 7 to 12 show a second embodiment of the present invention.

In this embodiment, the steps shown in FIGS. 7 to 10 are the same as those in the first embodiment. Next to FIG.
As shown in 1, is selectively removed by dilute hydrofluoric acid SiO ₂ film 3, then, polycrystalline silicon exposed result
A tungsten film 5 is formed on the shaft 2a and the surface of the rotating rotor (polycrystalline silicon) 4A (FIG. 12). In this case, if the CVD selective tungsten method is performed, a tungsten film 5 is formed on the exposed surface of the polycrystalline silicon.

In the method of manufacturing a micromachine according to the present embodiment, since the tungsten film 5 can be formed on the polycrystalline silicon shaft 2a and the rotating rotor 4A, the durability such as wear resistance and impact resistance of both can be obtained. Can be dramatically improved.

(Third Embodiment) FIGS. 13 to 18 are process sectional views showing a third embodiment of the present invention.

In this embodiment, first, a polycrystalline silicon shaft 2a is formed on a silicon substrate 1 as shown in FIG. After that, microwave C
Using a VD device, for example, a microwave output of 300 W
Then, about 0.5% of methane (CH ₄ ) is diluted with hydrogen (H ₂ ) gas, and the diamond thin film 6 is formed to a thickness of about 0.05 μm on the entire surface under the conditions of a gas pressure of 30 Torr and a substrate temperature of 800 ° C. (FIG. 14).

Further, as shown in FIG. 15, after depositing an SiO ₂ thin film 3 on the diamond thin film 6 by a CVD method, as shown in FIG. 16, polycrystalline silicon for forming a rotating rotor is formed. The film 4 is formed.

Next, as shown in FIG. 17, the polycrystalline silicon film 4 is patterned by lithography to form a rotating rotor 4A. Then, as shown in FIG. 18, by performing wet etching using diluted hydrofluoric acid or the like, the SiO ₂ thin film 3 is selectively removed, and the rotating rotor 4A is made rotatable.

In this embodiment, the polycrystalline silicon shaft 2
Since a is coated with the diamond thin film 6, the durability of the shaft can be significantly improved.

[0029] In the present embodiment, the polycrystalline silicon film 2a has a structure covering with a diamond thin film 6,
Sufficient durability can be obtained even with a structure coated with another carbon, for example, graphite-based carbon.

In the structure shown in FIG. 18, a tungsten film may be formed on the surface of the rotary rotor 4A in the same manner as in the second embodiment.

(Fourth Embodiment) FIGS. 19 to 24 show a fourth embodiment of the present invention.

First, in the present invention, FIGS.
As shown in FIG. 5, as in the conventional example, after the rotary rotor 4A is formed so as to be fitted to the polycrystalline silicon shaft 2a in a separated state, for example, a compound represented by (CH ₃ ) Si (OH) ₂ is lubricated. The material 7 is heated to about 100 ° C. to be in a liquid state, and is rotationally applied to the surface of the polycrystalline silicon shaft 2a and the surface of the rotary rotor 4A using a rotary coater as shown in FIG.

In this embodiment, by adopting such a structure, the sliding portion, that is, the rotation of the rotary rotor 4A and the polycrystalline silicon shaft 2a can be smoothly rotated, and the durability can be improved. .

Although the embodiments have been described above, the present invention is not limited to these embodiments, and various design changes are possible.

For example, in the above embodiment, the present invention has been described by applying the present invention to an electrostatic motor having a rotating rotor. In addition, for example, a micromachine having a rotating rotor as a rotor used in a pump, or another sliding machine may be used. It is of course possible to apply the present invention to a micromachine having a section.

[0036]

As is apparent from the above description, according to the method of manufacturing a micromachine according to the present invention, the insulating film is removed.
At the time of departure, the rotating rotor of polycrystalline silicon is etched
The dimensional accuracy is increased, and the durability such as the wear resistance of the sliding portion of the micromachine is significantly improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a manufacturing process of a first embodiment of the present invention.

FIG. 2 is a sectional view showing a manufacturing process of the first embodiment of the present invention.

FIG. 3 is a sectional view showing the manufacturing process of the first embodiment of the present invention.

FIG. 4 is a sectional view showing the manufacturing process of the first embodiment of the present invention.

FIG. 5 is a sectional view showing the manufacturing process of the first embodiment of the present invention.

FIG. 6 is a sectional view showing the manufacturing process of the first embodiment of the present invention.

FIG. 7 is a sectional view showing a manufacturing process according to a second embodiment of the present invention.

FIG. 8 is a sectional view showing a manufacturing process according to a second embodiment of the present invention.

FIG. 9 is a sectional view showing a manufacturing process according to the second embodiment of the present invention.

FIG. 10 is a sectional view showing a manufacturing process according to the second embodiment of the present invention.

FIG. 11 is a sectional view showing a manufacturing process according to a second embodiment of the present invention.

FIG. 12 is a sectional view showing a manufacturing process according to the second embodiment of the present invention.

FIG. 13 is a sectional view showing a manufacturing process according to a third embodiment of the present invention.

FIG. 14 is a sectional view showing a manufacturing process according to a third embodiment of the present invention.

FIG. 15 is a sectional view showing a manufacturing process according to a third embodiment of the present invention.

FIG. 16 is a sectional view showing a manufacturing process according to a third embodiment of the present invention.

FIG. 17 is a sectional view showing a manufacturing step according to a third embodiment of the present invention.

FIG. 18 is a sectional view showing a manufacturing process according to a third embodiment of the present invention.

FIG. 19 is a sectional view showing a manufacturing step according to a fourth embodiment of the present invention.

FIG. 20 is a sectional view showing the manufacturing process of the fourth embodiment of the present invention.

FIG. 21 is a sectional view showing a manufacturing step according to a fourth embodiment of the present invention.

FIG. 22 is a sectional view showing a manufacturing step according to a fourth embodiment of the present invention.

FIG. 23 is a sectional view showing the manufacturing process of the fourth embodiment of the present invention.

FIG. 24 is a sectional view showing a manufacturing step according to a fourth embodiment of the present invention.

FIG. 25 is a sectional view showing a manufacturing process of a conventional example.

FIG. 26 is a cross-sectional view showing a manufacturing process of a conventional example.

FIG. 27 is a sectional view showing a manufacturing process of a conventional example.

FIG. 28 is a sectional view showing a manufacturing process of a conventional example.

FIG. 29 is a cross-sectional view showing a manufacturing process of a conventional example.

FIG. 30 is a sectional view showing a manufacturing process of a conventional example.

FIG. 31 is a perspective view showing a state of a rotating rotor of the micro machine.

[Explanation of symbols]

1 ... silicon substrate, 2 ... polycrystalline silicon, 2a ... polycrystalline silicon shaft, 3 ... SiO ₂ thin film, 4 ... polycrystalline silicon film, 4A ... rotating rotor, 5 ... tungsten film, 6 ... diamond thin film, 7 ... lubricant .

Claims (1)

(57) [Claims] 1. A method of manufacturing a micromachine using silicon, comprising: forming a cylindrical silicon axis on a silicon substrate; and forming a diamond film on the entire surface of the silicon substrate and the silicon axis. Depositing an insulating film on the diamond film to form a rotating rotor made of polycrystalline silicon around the silicon axis, and removing the insulating film to separate the silicon shaft and the rotating rotor. A method for manufacturing a micromachine, comprising: a step of making a rotor rotatable.