JPH10335675A - Semiconductor micromachine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve measuring accuracy, by providing a spiral first coil on the movable part of a semiconductor micromachine that detects a distance displacement quantity between a substrate and the movable part from the detection value of a detection circuit. SOLUTION: A spiral first coil 18 is provided on a movable part 12. Magnetic field is generated on the first coil 18 by conduction. Repulsive force is generated between a substrate side electrode 111 and a movable part side electrode 121 by the magnetic field and the external magnetic field. Potential difference is applied to the substrate side electrode 111 and the movable part side electrode 121, so as to make the repulsive force equal to the electrostatic attracting force operating between the substrate side electrode 111 and the movable part side electrode 121. As higher potential difference can be applied to both electrodes and the signal current that flows in a detection circuit increases in proportion to the potential difference, the measuring accuracy of a semiconductor micromachine can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an acceleration sensor, an angular velocity sensor,
The present invention relates to a semiconductor micromachine usable as a physical quantity sensor such as a pressure sensor.

[0002]

2. Description of the Related Art Conventionally, a micromachining technology using a semiconductor material such as Si has been developed as a technology for producing minute acceleration sensors, angular velocity sensors, pressure sensors, and the like. According to this technique, it is possible to create the above-described sensor or the like as small as 1 mm or less by combining the techniques for creating a normal semiconductor circuit or the like. As an example of a product created by such a technique, there is a semiconductor micromachine that functions as an acceleration sensor as described below.

As shown in FIGS. 19 to 21, the semiconductor micromachine 9 is disposed so as to face a substrate 11 with a gap 100 provided between the substrate 11 and four needle-like members 13.
The movable part 12 is supported by the movable part 15. The substrate 11 and the movable portion 12 are provided with a substrate side electrode 111 and a movable portion side electrode 121, respectively.

As shown in FIG. 20, the substrate side electrode 111 is electrically connected to an electrode pad 143 via a wiring 144 provided on the substrate 11. On the other hand, as shown in FIGS. 19 and 21, the movable-part-side electrode 121 has a needle-like body 15, a support 159 for supporting the needle-like body 15, and a wiring 14.
2 and is electrically connected to the electrode pad 141. A detection circuit (not shown) is connected to the electrode pads 141 and 143. The detection circuit can detect the capacitance of the gap 100.

[0005] The acceleration detection using the semiconductor micromachine 9 can be performed as follows. First,
A potential difference is applied between the movable part side electrode 121 and the substrate side electrode 111. In this state, when a vertical acceleration is applied to the semiconductor micromachine 9 with respect to the substrate to be measured, the movable portion 12 is displaced. Therefore, the distance between the substrate 11 and the movable portion 12 also changes, and accordingly, the capacitance in the gap portion 100 changes.

The signal current accompanying the change in the capacitance is detected by the detection circuit. As described above, the movable unit 1
2 is detected by the detection circuit, and a detection value corresponding to the acceleration can be obtained here.

[0007] In other angular velocity sensors and pressure sensors, similarly, displacements and vibrations proportional to the angular velocity and pressure are generated in the movable part, and the detection circuit obtains detection values corresponding to these values.

[0008] The movable part in the semiconductor micromachine is manufactured as described below. First, a PSG is formed on the surface of the substrate 11 on which the substrate side electrode 111 and the like are provided in advance.
An etching layer made of (phosphorus glass) or the like is provided, and a semiconductor thin film is formed on the surface of the etching layer. Next, the semiconductor thin film is etched into the shape of the movable part 12 or the needle-like bodies 13 and 15. Thereafter, the etching layer is removed by using a wet process or the like. As described above, the gap 100 between the substrate 11 and the movable part 12 is formed, and the movable part 12 having a desired shape can be obtained.

[0009]

However, the above-mentioned semiconductor micromachine has the following problems. by the way,
The capacitance C between the two electrodes in the semiconductor micromachine is C = ε ₀ S / t, where S is the effective area of the movable part side electrode and the substrate side electrode, and t is the distance between the two electrodes. Ε ₀ is the dielectric constant of vacuum.

When the acceleration is applied to the substrate in the vertical direction, the change in the distance between the two electrodes is Δt, the change in the capacitance at this time is ΔC, and the potential difference applied between the two electrodes is V. Then, ΔC = C−ε ₀ S / (t + Δt) or ΔC = C−ε ₀ S / (t−Δt). Where t>
> Δt, ΔC is approximately CΔt / t (ie, ε ₀ SΔt / t ² ) or −CΔt / t (ie,
−ε ₀ SΔt / t ² ). At this time, the signal current I flowing through the detection circuit is I = d (ΔCV) / dT (T: time), and the measurement accuracy of the semiconductor micromachine increases as the signal current increases.

Therefore, to increase the measurement accuracy of the semiconductor micromachine, ΔC or V may be increased. Considering that ε ₀ is a constant, the following method can be considered. (1) Increase the effective area S. (2) The distance t between the two electrodes is reduced. (3) Increase Δt. That is, the spring constant of the needle-like body is reduced, or the mass of the movable part is increased, and the displacement of the movable part is increased. (4) Increase the potential difference V.

However, since there is a potential difference between the movable part side electrode and the substrate side electrode, an electrostatic attraction F acts between the movable part and the substrate. The electrostatic attraction F is F = V ² ε ₀ S / (2
t ² ). Therefore, (1), (2),
In the method (4), since the electrostatic attraction F also increases, there is a possibility that a problem that the movable portion and the substrate come into contact with and adhere to each other may occur.

In the method (3), in order to prevent the effective area S from increasing when the mass of the movable portion is increased, the thickness of the movable portion must be increased. However, the movable part is formed of a semiconductor thin film,
It is difficult to increase the thickness. That is, problems such as a decrease in productivity due to an increase in film formation time, an increase in distortion due to internal stress, and difficulty in etching are caused.

Further, by making the spring constant of the needle-shaped body smaller, the movable part swings with a smaller external force. Therefore, there is a possibility that a problem that the movable portion and the substrate come into contact with and adhere to each other due to the electrostatic attraction may occur.

As described above, in the manufacture of the above-mentioned semiconductor micromachine, a wet process is sometimes used. In this case, the movable portion comes into contact with the substrate due to the surface tension of the processing solution and is stuck and does not separate. There is a problem that a sticking phenomenon that occurs occurs. The semiconductor micromachine in which this phenomenon has occurred is a defective product, which has led to a reduction in the manufacturing yield.

Note that the sticking phenomenon may occur in a completed semiconductor micromachine. That is, this is a case where an electrostatic attraction due to static electricity or the like acts between the substrate and the movable portion. Therefore, strict attention was required when handling conventional semiconductor micromachines.

In view of the above problems, the present invention provides a semiconductor micromachine which can be used as a physical quantity sensor such as an acceleration sensor, an angular velocity sensor, a pressure sensor, etc., has a high measurement accuracy, a high production yield rate, and is easy to handle. It is intended to provide.

[0018]

According to a first aspect of the present invention, there is provided a semiconductor device comprising: a substrate; and a movable portion which is disposed to face the substrate with a gap provided therebetween and is supported by a needle-like body. Is provided with a substrate side electrode and a movable part side electrode, respectively, and further has a detection circuit for detecting a capacitance between the substrate side electrode and the movable part side electrode, and a detection value of the detection circuit. In a semiconductor micromachine for detecting a distance displacement amount between the substrate and the movable portion or a displacement amount of the movable portion of the movable portion with respect to the substrate, the movable portion is provided with a spiral first coil. Semiconductor micromachine.

The first coil is formed of a conductive thin film formed on the movable part. The shape is "spiral shape"
It is. This expression includes various spiral shapes such as a circular spiral shape in addition to an angular spiral shape as shown in FIG. 1 described later.

The operation of the present invention will be described below. In the semiconductor micromachine according to the present invention, the movable portion is provided with a spiral first coil. The semiconductor micromachine is magnetized in a direction perpendicular to the substrate, and the semiconductor micromachine is placed in a magnetic field (correctly, in a divergent magnetic field). The first coil generates a magnetic field when energized. This magnetic field produces a repulsive force between the substrate and the movable part. For this reason, it is possible to prevent the movable section from contacting the substrate.

Further, if the movable part is in contact with the substrate,
Even in the case of sticking (even when sticking occurs), the magnetic field generated by the first coil can separate them.

For this reason, it is possible to prevent the problem of contact and fixation of the movable part and the substrate which occurs in the method of improving the measurement accuracy of the semiconductor micromachine presented in the above-mentioned prior art. For this reason, the semiconductor micromachine according to the present invention has excellent measurement accuracy.

Further, even when a sticking phenomenon occurs during the manufacturing, the movable portion and the substrate can be separated by energizing the first coil, so that the manufacturing yield can be increased. In addition, the operation for preventing the occurrence of the sticking phenomenon can be eliminated. Therefore, handling of the semiconductor micromachine according to the present invention is easy.

Further, the first coil can be easily manufactured by a semiconductor process for manufacturing the semiconductor micromachine. Therefore, no special process is required,
The semiconductor micromachine can be manufactured at low cost. Also, since the first coil has a spiral shape,
When the movable part vibrates in a direction parallel to the substrate (for example, an angular velocity sensor), the change in the center of gravity of the vibrating movable part is small, and the vibration of the movable part is stabilized. For this reason, deterioration of the characteristics of the semiconductor micromachine can be suppressed.

As described above, according to the present invention, a semiconductor which can be used as a physical quantity sensor such as an acceleration sensor, an angular velocity sensor, a pressure sensor, etc., has a high measurement accuracy, a high production yield rate, and is easy to handle. A micromachine can be provided.

The semiconductor micromachine according to the present invention can be applied to a sensor having a mechanism for detecting some value by using the displacement of a movable portion, in addition to the above-described sensor.

Next, as in the second aspect of the present invention, it is preferable that the first coil is provided on the side opposite to the substrate with respect to the movable section side electrode (see FIG. 2 described later). Thus, it is possible to prevent noise from being mixed into the detected value due to the current supply to the first coil.

Next, it is preferable that the substrate is made of a permanent magnet. Thereby, the repulsive force between the substrate and the movable portion can be further increased. Also, since a magnetic field can be generated without using an external power supply,
Electrode pads for applying a magnetic field, circuits, wiring, and the like can be eliminated, and the structure of the semiconductor micromachine can be simplified.

Next, the magnetic field of the permanent magnet is preferably formed in a direction perpendicular to the substrate. Thereby, the magnitude of the repulsive force between the substrate and the movable part can be maximized.

Next, it is preferable that the substrate is provided with a spiral second coil. Thereby, the repulsive force between the substrate and the movable portion can be further increased. The second coil is made of Si-I
Since the semiconductor micromachine can be manufactured by the C process, the manufacturing process of the semiconductor micromachine can be simplified. Further, the size of the semiconductor micromachine can be reduced.

Next, it is preferable that the second coil is provided on the side opposite to the movable portion with respect to the substrate-side electrode. Thus, it is possible to prevent the noise from being mixed into the detection value due to the energization of the second coil.

Next, it is preferable that the first coil and the second coil are connected in series or in parallel. Thus, a circuit for applying a current to the first coil and the second coil can be shared, and the structure of the semiconductor micromachine can be simplified.

Next, the movable portion is provided with a movable portion side wiring together with the movable portion side electrode, and the first coil is connected to the movable portion side electrode and the movable portion side. It is preferable that the wiring is electrically insulated. This makes it difficult for crosstalk (movement of electric charge) to occur between the first coil and the movable section side electrode and the movable section side wiring, thereby increasing the S / N ratio and increasing the measurement sensitivity.

Next, the second coil and the substrate-side electrode are preferably electrically insulated. In this case as well, the S / S
The measurement ratio can be increased by increasing the N ratio.

Next, according to a tenth aspect of the present invention, based on a magnetic field in a direction perpendicular to the substrate and a signal value obtained from the detection circuit, the variation of the capacitance is suppressed so as to suppress the variation of the capacitance. It is preferable that a first coil current control circuit for controlling a current value flowing through one coil be provided.

Thus, since the displacement of the movable portion can be suppressed, the range of detectable physical quantities can be widened. Further, it is possible to use a region under which the variation of the capacitance with respect to the displacement of the movable portion is closer to a proportional relationship, and it is possible to obtain a semiconductor micromachine having excellent linearity of the detected value. It should be noted that superior linearity means that the deviation of the proportional relationship between the change in the measured physical quantity and the output is small.

Next, according to the eleventh aspect of the present invention, based on the signal value obtained from the detection circuit, the current value flowing through the first coil and the second coil so as to suppress the fluctuation of the capacitance. It is preferable to provide a first coil current control circuit and a second coil current control circuit for controlling the current.

Thus, the magnitude of the magnetic field generated by the first coil and the magnitude of the magnetic field generated by the second coil can be adjusted, and the magnitude of the repulsive force between the substrate and the movable portion can be adjusted. . Thus, since the displacement of the movable section can be suppressed, the displacement of the movable section with respect to the change of the measurement target can be reduced. Therefore, the range of detectable physical quantities can be widened. In addition, a change in capacitance with respect to the displacement of the movable portion is inversely proportional to the distance between the electrodes. However, by suppressing the displacement, a semiconductor micromachine with high linearity capable of operating in a region where the nonlinearity of the capacitance change is small is obtained. be able to.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment A semiconductor micromachine according to an embodiment of the present invention will be described with reference to FIGS. Note that the semiconductor micromachine according to the present example is used as an acceleration sensor.

As shown in FIGS. 1 to 3, the semiconductor micromachine 1 of this embodiment includes a substrate 11 and a gap 10 between the substrate 11 and the substrate 11.
0, and four needle-like bodies 13, 1
The movable part 12 is supported by the movable parts 5 and 16. The substrate 11 and the movable part 12 are provided with a substrate-side electrode 111 and a movable-part-side electrode 121, respectively. Further, a detection circuit for detecting the capacitance between the substrate side electrode 111 and the movable portion side electrode 121 is provided. The movable portion 12 is provided with a spiral first coil 18.

The details will be described below. As shown in FIG. 2, the surface of the substrate 11 is covered with an insulating film 110,
The substrate side electrode 111 and the wiring 14 are provided on the surface of the insulating film 110.
2, 144 and an etching layer 113 are provided. The above-mentioned etching layer 113 has electrode pads 141, 143, 14
5 are provided, and a part of the wirings 142 and 144 pass through the lower portion of the etching layer 113 to the electrode pads 141 and 1.
43 is connected to the lower part. The etching layer 113 is made of an insulating film 1 made of PSG (phosphor glass), SiO ₂ or the like.
It is preferable to use a material which has a high selectivity to 10 and is easily etched.

As shown in FIG. 2, the substrate side electrode 111 is formed integrally with the wiring 144. Therefore, the substrate-side electrode 111, the wiring 144, and the electrode pad 143 are in an electrically conductive state.

The movable part 12 has four needles 13, 1
5 and 16 support the substrate 11. The two needles 13 have a role of only supporting the movable part 12. On the other hand, the needle 15 supports the movable portion 12 and also has a role as a wiring. A wire 182 is provided on the surface of the needle-like body 16. The etching layer 113 is a portion that remains when the needles 13, 15, 16 and the movable portion 12 are formed (see Embodiment 2).

As shown in FIG. 1 and FIG.
Is the movable portion side electrode 12 covered on the upper surface with the insulating film 120
1. On the surface of the insulating film 120, a first coil 18 made of a spiral thin film is provided. The insulating film 120 below the central portion 180 of the first coil 18 is provided with a through hole 122 in which the first coil 18 and the movable portion side electrode 12 are formed.
1 and electrical continuity are secured.

The first coil 18 is provided on a surface of the movable portion 12 that does not face the substrate 11. That is, the first coil 18 is provided on the side opposite to the substrate 11 with respect to the movable section side electrode 121.

The movable portion side electrode 121 is connected to the needle 1
5, through the support portion 159 of the needle-like body 15 and the wiring 142 provided below the support portion 159, the electrode pad 14
1 electrically. On the other hand, the first coil 1
8, the conduction between the through hole 122 and the central portion 180 is established.
The end 181 is the needle 16 and the support 1 of the needle 16.
It is electrically connected to the electrode pad 145 via a wiring 182 provided on the surface of the 69. The detection circuit 52 is connected to the electrode pads 141 and 143. A power supply 51 is connected to the electrode pads 141 and 145 (see FIG. 4).

Further, in the semiconductor micromachine 1 according to the present embodiment, the movable-part-side electrode 121, the needle-shaped body 13, 1
5, 16, the first coil is made of n-type polycrystalline Si. Further, the insulating films 110 and 120 are made of a Si nitride film.
The substrate 11 is made of single crystal Si.

The first coil 18 is made of p-type polycrystalline S
i, p-type and n-type amorphous Si, gold, platinum, V, Nb, T
A conductor that is difficult to be etched, such as a, W, Mo, molybdenum silicide, or tungsten silicide, can be used. Further, the insulating film can be formed of a Si oxide film, an Al nitride film, an Al oxide film, or the like. Further, the movable portion 12 is n-type or p-type Si, Ge, C, Si _x
Ge _1-x, SiC, may be composed of Si _x Ge _y C consisting of _1-xy polycrystalline thin film or amorphous film.

Further, a pn junction, ni
The movable portion side electrode 12 is formed so that a junction and a pi junction are formed.
1. The material of the first coil 18 can also be selected. In this case, the process can be simplified, and the cost can be reduced. The same can be said for the inside of the substrate 11. The semiconductor micromachine 1 is provided with a coil or a permanent magnet outside in order to apply an external magnetic field described later.

Next, detection of acceleration by the semiconductor micromachine 1 will be described. An external magnetic field is applied in a direction perpendicular to the substrate 11. Further, a current is supplied from the power supply 51 to the first coil 18 so that a repulsive force acts between the substrate 11 and the movable portion 12. The movable section side electrode 121 is grounded via an electrode pad 141. The substrate-side electrode 111 is maintained at a constant potential via the electrode pad 143. Thereby, the movable portion side electrode 12
1 and the substrate side electrode 111 are applied with a potential difference.

The potential of the substrate-side electrode 111 is controlled by controlling the current flowing through the first coil 18 via the electrode pad 145, so that the substrate-side electrode 111 and the movable part-side electrode 121 are controlled.
And the electrostatic attraction acting between the substrate side electrode 111 and the movable part side electrode 121 are made equal.

When an acceleration to be measured is applied to the semiconductor micromachine 1 in this state, the distance between the substrate 11 and the movable section 12 changes in proportion to the magnitude of the acceleration.

As shown in the above-mentioned prior art, assuming that a change in distance is Δt, a change in capacitance is ΔC, and a potential difference between both electrodes is V, ΔC is approximately CΔt / t (ie, ε
₀ SΔt / t ² ) or −CΔt / t (ie, −ε ₀
SΔt / t ² ). The signal current I flowing through the detection circuit 52 is I = ΔCV. The acceleration can be measured by the detection circuit 52 detecting the signal current.

Next, the operation and effect of this embodiment will be described. In the semiconductor micromachine 1 according to this example,
The movable portion 12 is provided with a spiral first coil 18. A magnetic field is generated in the first coil 18 by energization. Due to this magnetic field and the external magnetic field, a repulsive force is generated between the substrate side electrode 111 and the movable section side electrode 121. Then, the substrate side electrode 111 and the movable part side electrode 121 are so adjusted that the repulsive force and the electrostatic attractive force acting between the substrate side electrode 111 and the movable part side electrode 121 become equal.
Is applied with a potential difference.

For this reason, a higher potential difference can be applied between the electrodes 121 and 111 in the micromachine of the present embodiment than in the case where there is no repulsive force. Since the signal current I flowing through the detection circuit 52 also increases in proportion to the potential difference (I = d (ΔCV) / dT),
The measurement accuracy of the semiconductor micromachine 1 also increases.

It should be noted that the substrate 11 of the semiconductor micromachine 1 according to the present embodiment may be formed of a permanent magnet magnetized in a direction perpendicular to the substrate 11. In this case, since no external magnetic field is required, the semiconductor micromachine 1 can be made more compact.

Further, as shown in FIG. 4, the detection circuit 52 and the power supply 5 of the semiconductor micromachine 1 according to the present embodiment.
For example, a first coil current control circuit 53 that performs feedback control of the power supply 51 according to the value of the signal current detected by the detection circuit 52 may be provided. When the value of the signal current in the detection circuit 52 increases or decreases, the first coil current control circuit 53 increases or decreases the current flowing through the first coil 18 so as to cancel out the increase or decrease in the signal current, and the first coil current control circuit 53 and the substrate side electrode 111 It has a function of increasing or decreasing the repulsive force acting between the movable portion side electrode 121 and the movable portion side electrode 121.

Embodiment 2 This embodiment is, as shown in FIGS. 5 to 18, a semiconductor micromachine having a movable portion provided with a first coil and a substrate provided with a second coil. As shown in FIGS. 5 to 7, the surface of the substrate 11 of the semiconductor micromachine 2 is covered with an insulating film 110.
A spiral second coil 22 is formed on the surface of the insulating film 110.
Is provided. The second coil 22 is composed of insulating films 211 and 211.
At 12, it is insulated from the substrate side electrode 111. Also,
As described later, the second coil 22 is connected to the electrode pads 247 and 249 by wiring 23 while ensuring electrical continuity.

As shown in FIG. 16, a detection circuit 52 is connected to the electrode pads 141 and 143.
A power supply 54 is connected to the electrode pads 247 and 249, and the power supply 54 supplies a current to the second coil 22.
A power supply 51 is connected to the electrode pad 145,
From this, an electric current is applied to the first coil 18 so that the movable portion side electrode 1
A voltage is applied to 21. A first coil current control circuit 53 is provided between the detection circuit 52 and the power supply 51. Others are the same as the first embodiment.

Next, a method of manufacturing the semiconductor micromachine 2 according to the present embodiment will be described. First, the substrate 11 is prepared. Next, an insulating film 110 is formed on the surface of the substrate 11. Next, as shown in FIG. 8, a wiring 23 is formed on the surface of the insulating film 110. Then, as shown in FIG.
An insulating film 211 is formed, and ends 231 and 231 of the wiring 23 are formed.
A through hole is formed in the insulating film 211 so that 32 is exposed.

Next, as shown in FIG.
The second coil 22, wirings 246, 248, and pads 240 are formed on the surface of the eleventh embodiment. At this time, the center part 220 of the second coil 22 is formed at a position overlapping the end part 232. That is, in the center portion 220, the wiring 23
And the second coil 22 conducts. The wiring 24
6 at the position overlapping the end 232 of the wiring 23,
The wiring 248 is provided integrally with the second coil 22. A pad 240 is formed at an end of the wiring 246 and the wiring 248.

Next, as shown in FIG.
And a through hole is formed such that a part of the pad 240 is exposed. Next, as shown in FIG. 12, electrode pads 141, 143,
247, 249, the substrate-side electrode 111, the wiring 144, the pad 150, and the wiring 142 are formed.

The pad 150 is provided for electrically connecting the needle 15 and the electrode pad 141 via the supporting portion 159 of the needle 15. The electrode pads 247 and 249 are provided on the pad 240 while ensuring electrical continuity.

Next, as shown in FIG. 13, an etching layer 26 is provided. However, the electrode pads 141, 143,
247, 249 and a part of the pad 150 are exposed, and the portions of the needles 13, 16 where the support portions 139, 169 are to be formed are etched so that the insulating film 212 is exposed. 160 are provided. afterwards,
The etching layer 26 and the electrode pads 141, 143,
247, 249, etc.
A film is provided, and an insulating film 120 is further provided on the surface. Further, a through hole 122 is provided in the insulating film 120.

Next, as shown in FIG.
Reference numeral 20 denotes a first coil 18, a wiring 182, and an electrode pad 145.
Is provided. At this time, the central portion 180 of the first coil 18 is electrically connected to the n-type polycrystalline Si film through the through hole 122. Next, the movable part 12, the needle-like body 16
The insulating film 120 other than the portion to be formed is removed by etching. Further, the movable part 12, the needle-like bodies 13, 15, 16, the wiring 182, the electrode pads 141, 247, 193, 24
The n-type polycrystalline Si film other than the portion that becomes 9,145 is removed by etching. Thus, as shown in FIG. 15, all the electrode pads 141, 143, 145, 24
7,249 are exposed outside.

Further, these electrode pads 141, 14
A metal layer is provided on the surface of 3,145,247,249. However, at this stage, the movable part 12 and the substrate 11 have not been separated yet.

Next, the portions other than the needles 13, 15, 16 and the vicinity thereof are protected by resist, and the needles 13, 15, 16 are protected.
The gap between the movable portion 12 and the substrate 11 is separated by etching while leaving portions 15 and 16 to form a gap portion 100. Further, the resist is removed. From the above,
As shown in FIG. 5, a semiconductor micromachine 2 according to this example was obtained.

In the semiconductor micromachine 2 of this embodiment, the first coil 18 is provided on the movable part 12 and the second coil 22 is provided on the substrate 11. Then, the first coil 18 and the second coil 22 are energized respectively, and both the coils 18 and 22 are turned on.
Generates a repulsive force between the movable part side electrode 121 and the substrate side electrode 111. Therefore, an external magnetic field is not required, and the size of the semiconductor micromachine can be reduced. Further, since there is no need to configure the substrate with permanent magnets, it is possible to manufacture by a normal semiconductor process. For this reason, the cost for the manufacturing equipment is reduced.
Others have the same operation and effects as the first embodiment.

In the semiconductor micromachine 2 of this embodiment, a conductive layer sandwiched by an insulating layer between the substrate-side electrode 111 and the second coil 22 can be inserted to maintain the conductive layer at a constant potential. . Thereby, the second coil 22
And the capacitance between the substrate side electrode 111 can be reduced,
The noise level of the signal can be reduced.

Further, in the semiconductor micromachine 2 of this embodiment, the first coil 18 and the second coil 22 can be connected in series or in parallel. As a result, the magnetic field control circuit can be unified, and the circuit can be simplified.

As shown in FIG. 17, in the semiconductor micromachine 2 of this embodiment, the electrode pads 141, 1
43, a detection circuit 52 is connected to the electrode pad 247,
The power supply 54 is connected to the power supply 249, the power supply 51 is connected to the electrode pad 145, and the detection circuit 52 is connected to the power supply 5.
4, a second coil current control circuit 55 may be provided.

Thus, the value of the current flowing through the second coil 22 can be controlled according to the magnitude of the signal current of the detection circuit 52, and can be used as a servo mechanism.
Thereby, the linearity can be improved and the dynamic range can be expanded.

As shown in FIG. 18, in the semiconductor micromachine 2 of this embodiment, the electrode pads 141, 1
43, a detection circuit 52 is connected to the electrode pad 247,
The power supply 54 is connected to the power supply 249, the power supply 51 is connected to the electrode pad 145, the first coil current control circuit 53 is provided between the detection circuit 52 and the power supply 51, and the detection circuit 52 and the power supply 54 are connected to the power supply 51. Between the second coil current control circuit 5
5 may be provided.

Also in this case, the value of the current flowing through the first coil 18 and the second coil 22 can be controlled according to the magnitude of the signal current of the detection circuit 52, and can be used as a servo mechanism. In addition, the linearity can be improved, and the dynamic range can be expanded.

According to the present invention, there is provided a semiconductor micromachine which can be used as a physical quantity sensor such as an acceleration sensor, an angular velocity sensor, a pressure sensor, etc., has a high measurement accuracy, a high production yield rate, and is easy to handle. can do.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view of a semiconductor micromachine used as an acceleration sensor according to a first embodiment;

FIG. 2 is an explanatory cross-sectional view of the semiconductor micromachine taken along the line AA according to the first embodiment;

FIG. 3 is an explanatory cross-sectional view of the semiconductor micromachine according to the first embodiment, taken along the line BB;

FIG. 4 is an explanatory diagram of a first coil current control circuit of the semiconductor micromachine according to the first embodiment.

FIG. 5 is an explanatory plan view of a semiconductor micromachine provided with a second coil on a substrate according to a second embodiment;

FIG. 6 is an explanatory cross-sectional view of a semiconductor micromachine according to a second embodiment, taken along the line AA.

FIG. 7 is an explanatory cross-sectional view of the semiconductor micromachine according to the second embodiment, taken along the line BB.

FIG. 8 is an explanatory diagram according to a second embodiment, in which wiring is provided on a substrate.

FIG. 9 is an explanatory diagram according to a second embodiment in which an insulating film is formed.

FIG. 10 is an explanatory diagram according to a second embodiment, in which a second coil and a wiring are provided.

FIG. 11 is an explanatory view illustrating an insulating film according to the second embodiment.

FIG. 12 is an explanatory diagram according to a second embodiment, in which a substrate-side electrode and a wiring are provided.

FIG. 13 is an explanatory view showing an example in which an etching layer is formed according to the second embodiment.

FIG. 14 is an explanatory view according to the second embodiment, in which a first coil and a wiring are provided.

FIG. 15 is an explanatory view showing a movable portion and a needle-like body according to the second embodiment.

FIG. 16 is an explanatory diagram of a first coil current control circuit of the semiconductor micromachine according to the second embodiment.

FIG. 17 is an explanatory diagram of a second coil current control circuit of the semiconductor micromachine according to the second embodiment.

FIG. 18 is an explanatory diagram of a first coil current control circuit and a second coil current control circuit of the semiconductor micromachine according to the second embodiment.

FIG. 19 is an explanatory plan view of a semiconductor micromachine according to a conventional technique.

FIG. 20 is an explanatory cross-sectional view of a semiconductor micromachine taken along line EE according to a conventional technique.

FIG. 21 is an explanatory cross-sectional view of a semiconductor micromachine taken along line FF according to a conventional technique.

[Explanation of symbols]

 1. . . Semiconductor micromachine, 100. . . Gap portion, 11. . . Substrate, 111. . . 11. substrate-side electrode; . . Movable part, 121. . . Movable part side electrode, 18. . . First coil, 13, 15, 16. . . Needles, 22. . . Second coil, 52. . . Detection circuit, 53. . . First coil current control circuit, 55. . . Second coil current control circuit,

Claims (11)

[Claims] 1. A substrate and a movable part which is disposed opposite to the substrate with a gap provided therebetween and supported by a needle-like body, and wherein the substrate and the movable part have a substrate-side electrode and a movable part, respectively. And a detection circuit for detecting a capacitance between the substrate-side electrode and the movable-part-side electrode. The detection circuit detects the capacitance between the substrate-side electrode and the movable-part-side electrode. A semiconductor micromachine for detecting a distance displacement amount of the movable portion of the movable portion with respect to the substrate or a movable portion provided with a spiral first coil in the movable portion. 2. The semiconductor micromachine according to claim 1, wherein the first coil is provided on a side opposite to the substrate with respect to the movable portion side electrode. 3. The semiconductor micromachine according to claim 1, wherein said substrate is made of a permanent magnet. 4. The semiconductor micromachine according to claim 3, wherein the magnetic field of the permanent magnet is formed in a direction perpendicular to the substrate. 5. The semiconductor micromachine according to claim 1, wherein the substrate is provided with a spiral second coil. 6. The semiconductor micromachine according to claim 5, wherein the second coil is provided on a side opposite to the movable portion with respect to the substrate-side electrode. 7. The semiconductor micromachine according to claim 5, wherein the first coil and the second coil are connected in series or in parallel. 8. The method according to claim 1, wherein:
The movable part is provided with a movable part side wiring together with the movable part side electrode, and the first coil is electrically insulated from the movable part side electrode and the movable part side wiring. Semiconductor micromachine. 9. The method according to claim 5, wherein
A semiconductor micromachine wherein the second coil and the substrate-side electrode are electrically insulated. 10. The first coil according to claim 1, wherein the first coil is configured to suppress a change in the capacitance based on a magnetic field in a direction perpendicular to the substrate and a signal value obtained from the detection circuit. A semiconductor micromachine comprising: a first coil current control circuit for controlling a flowing current value. 11. The first coil and the second coil according to claim 5, wherein a change in the capacitance is suppressed based on a signal value obtained from the detection circuit. A semiconductor micromachine comprising a first coil current control circuit and a second coil current control circuit for controlling a current value.