JP2001156350A - Semiconductor micro actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge the displacement of a movable part (movable element) with a simple structure. SOLUTION: A semiconductor micro actuator 1A is provided with a movable part 8 comprising four flexible regions 2 which displace according to temperature change and thin films 4A formed on the upper surfaces of the flexible regions 2, and frame-like semiconductor substrate 3 supporting the flexible regions 2 sides of the movable part 8. Here, a heat insulating region 7 is provided between the flexible region 2 and the semiconductor substrate 3, while the thin film 4A on the heat insulating region 7 side is substantially thick. In short, the thin film 4A is provided at a part of the upper surface of flexible region 2 positioned on the heat insulating region 7 side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a movable portion having at least one flexible region which is displaced in response to a temperature change and a thin film formed on one surface of the flexible region.
The present invention relates to a semiconductor microactuator comprising: a semiconductor substrate that supports the flexible region side of the movable portion.

[0002]

2. Description of the Related Art A semiconductor substrate, a flexible region which is separated from the semiconductor substrate and is displaced by a change in temperature, and a heat insulating structure composed of a heat insulating region provided therebetween are different from each other. At least 2 having a coefficient of thermal expansion
There is a semiconductor microactuator that combines two materials (bimetal structure), heats that portion, and obtains displacement using the difference in thermal expansion coefficient. This semiconductor microactuator is disclosed in Japanese Unexamined Patent Publication No. Hei 4-506392, "Semiconductor microactuator" and Japanese Patent Laid-Open No. Hei 5-506392.
187574 describes "ultra-small valve".

The semiconductor microactuator described in Japanese Patent Publication No. 4-506392 is as shown in a top view of FIG. 8 and a sectional view of FIG.
00 has a bimetal structure in which an aluminum thin film 104 is formed in part. When a current is applied to the heater 101 formed in the diaphragm 100 made of silicon, heat is generated and the temperature of the diaphragm 100 rises. here,
Since silicon and aluminum have significantly different coefficients of thermal expansion, thermal stress is generated to deflect the diaphragm 100 and cause the movable portion 105 to be displaced. In order to obtain an efficient displacement, a hinge 103 made of a silicon dioxide thin film is provided between the periphery of the diaphragm 100 and the silicon frame 102.
Is provided to prevent heat generated in the diaphragm 100 from escaping to the silicon frame 102.

[0004] However, the semiconductor microactuator having such a structure has the following problems. First, the thermal insulation effect of the hinge structure of the silicon dioxide thin film will be considered. Generally, heat Q escaping from a high temperature portion to the low temperature portion Q (W) = - a _{λ (t 2 -t 1) /} δ · A ( Formula X).

Here, Q is a heat flow (speed of heat transfer), t ₂
−t ₁ is the temperature difference (° C.), δ is the distance from the heat source (cm),
A is a cross section perpendicular to the direction of heat flow (cm ² ), and λ is thermal conductivity (J / cm · s · ° C.).

Therefore, the amount of heat escaping from the diaphragm 100 to the silicon frame 102 is calculated using this relational expression.
The temperature difference between the diaphragm 100 and the silicon frame 102 is set to 15
0 ° C., width of hinge 103 is 30 μm, diaphragm 1
00 has a diameter of 2.5 mm, and the thickness of the hinge 103 is 2 μm.
("Electrically-Activated, Micromachined Diaphr
am Valves '' Technical Digest IEEE Solid-Stat
e Sensor and Actuator Workshop, pp65-69, June
Estimated from 1990), the section A1 perpendicular to the direction of heat flow
A1 = 2.5 mm × π × 2 μm = 0.25 cm × π × 2 × 10 ⁻⁴ cm = 1.57 × 10 ⁻⁴ cm ² , and the thermal conductivity of silicon dioxide λ = 0.084 (W /
cm · ° C.), the heat Q1 that escapes is: Q1 = 0.084 (W / cm · ° C.) × 150 ° C./(30
× 10 ⁻⁴ cm) × 1.57 × 10 ⁻⁴ cm ² = 0.66W = 660 mW. Next, the case where the hinge structure of silicon dioxide is not provided is calculated. When the thickness of the silicon diaphragm 100 is 10 μm and the cross section A2 perpendicular to the direction of the heat flow is calculated, A2 = 2.5 mm × π × 10 μm = 0.25 cm × π × 10 × 10 ⁻⁴ cm = 7.85 × 10 ⁻⁴ cm ² , and the thermal conductivity of silicon λ = 1.48 (W / cm ·
° C), the heat Q2 that escapes is: Q2 = 1.48 (W / cm · ° C) x 150 ° C / (30 x
10 ⁻⁴ cm) × 7.85 × 10 ⁻⁴ cm ² = 58 W Thus, by providing the hinge 103 made of a silicon dioxide thin film, a thermal insulation effect of about 90 times was obtained. As described above, the semiconductor microactuator described in Japanese Patent Publication No. 4-506392 has a structure with higher thermal efficiency than that of the conventional structure. However, in consideration of the current use, further reduction of heat loss is desired. Specifically, this heat release (heat loss) is considered to be power (power consumption) constantly supplied to maintain the diaphragm 100 at a predetermined temperature (for example, 150 ° C.).

Therefore, the power consumption of the semiconductor microactuator described in Japanese Patent Publication No. 4-506392 can be estimated to be several hundred mW (660 mW in calculation). In consideration of this, it is desirable that the power is not more than 100 mW.

In the semiconductor microactuator described in Japanese Patent Application Laid-Open No. 4-506392, the portion of the hinge 103 of the silicon dioxide thin film is as thick as 2 μm. The factor that determines the thickness of the silicon dioxide thin film of the hinge 103 is not clearly described in the specification. However, when the semiconductor microactuator is used for a microvalve or the like, the pressure applied to the movable element is expected to concentrate on the hinge 103, and a film thickness that does not break the pressure is required. Become. However, when the thickness of the hinge 103 is increased, the thermal insulation effect is reduced according to the above-described heat release calculation formula. Therefore, it can be estimated that 2 μm is determined as the thickness of the silicon dioxide thin film having a certain strength and a thermal insulation effect.

Next, the necessity of increasing the thickness of the silicon dioxide thin film of the hinge 103 will be considered. Tokuhyo Hei 4-5063
No. 92, the semiconductor microactuator
As described in the specification, the structure is movable by a bimetal composed of a diaphragm 100 made of silicon and an aluminum thin film 104. However, in order to obtain electrical insulation between the diaphragm 100 and the aluminum thin film 104, silicon dioxide is used. A thin film 106 has been inserted.

In the semiconductor manufacturing process, the silicon dioxide thin film 106 and the silicon dioxide thin film of the hinge 103 are formed at the same time, and it is desirable that these film thicknesses are the same. However, the diaphragm 100 and the aluminum thin film 1
When the thickness of the silicon dioxide thin film 106 inserted between the layers 04 becomes as large as 2 μm, it can be expected that the bimetal characteristic as a driving source is deteriorated. Literature ("Electric
ally-Activated, Micromachined Diaphram Valves "
Technical Digest IEEE Solid-State Sensor a
nd Actuator Workshop, pp. 65-69, June 1990), the thickness of the aluminum thin film 104 is 5 to 6 μm. Then, if a silicon dioxide thin film 106 having a thickness of 2 μm is inserted between the diaphragm 100 and the aluminum thin film 104, the diaphragm 1 at the time of heating can be obtained.
It can be easily presumed that it becomes a factor that hinders the deflection of 00.

In the semiconductor manufacturing process, a silicon dioxide thin film is usually formed at a high temperature of about 1000 ° C. Therefore, in consideration of the thermal expansion coefficient of silicon and silicon dioxide, the silicon diaphragm 100-silicon dioxide thin film 10
It is considered that a considerable internal stress is generated between 6.
This internal stress increases as the thickness of the silicon dioxide thin film 106 increases, which causes a reduction in bimetal characteristics. Considering the above points, the silicon dioxide thin film 106 between the diaphragm 100 and the aluminum thin film 104 is as thin as possible (2 × 10 ⁻⁸ m (200
Å)), and the silicon dioxide film of the hinge 103 must be somewhat thick (2 μm). However, forming such a thin film of silicon dioxide requires a very complicated semiconductor manufacturing process.
The specification of 506392 does not mention the production method.

As an improvement, US Pat. 5,27
1,597 discloses another hinge structure. This is not the silicon dioxide thin film structure as described above, but the silicon dioxide thin film between the hinge portion and the diaphragm-aluminum thin film has the same thickness. In this method, in order to make the silicon dioxide thin film in the hinge part thinner and to compensate for the decrease in strength of the hinge part caused by this, a part of the diaphragm and the silicon frame is used in addition to the hinge, and a part of the silicon of the diaphragm is used. It is not designed to reduce the power consumption of the actuator.

As described above, many problems still remain in the thermal insulation structure of the semiconductor microactuator.

The microminiature valve described in Japanese Patent Application Laid-Open No. Hei 5-187574 also combines at least two materials having different coefficients of thermal expansion, heats the portion, and obtains a displacement by utilizing the difference between the coefficients of thermal expansion. Semiconductor microactuators are used. The thermal insulation structure of this microactuator is performed by providing a torsion bar type suspension. This structure minimizes heat loss to the silicon frame by both reducing the cross section perpendicular to the heat flow and increasing the path length through which the heat flow passes. However, since this torsion bar type suspension structure is formed of silicon, it is considered that a sufficient thermal insulation effect cannot be obtained as considered in the calculation of heat escape.

This is described in the document "SILICON MICROVALVES FOR
GAS FLOW CONTROL '' The 8th International Conference
on Solid-State Sensor and Actuators, Stockholm, Swe
Den, 1995, pp. 276-279, can be estimated from the microvalve performance comparison table. In this document, Japanese Translation of PCT Publication No. 4-5
Japanese Patent Application Laid-Open No. 5-18775
No. 74 discloses a bicycle valve relating to an “ultra-small valve”, and the latter has a pressure resistance of 6 times and a flow rate range of 10 times that of the former, but consumes about 2 times.
The thermal resistance is about 1/3.

As described above, the microminiature valve described in Japanese Patent Application Laid-Open No. 5-187574 is a microactuator that can generate a large force by a torsion bar type suspension structure made of silicon. It does not meet the needs of small and portable devices.

[0017]

In consideration of the above circumstances, a semiconductor microactuator having a high thermal insulation efficiency and a simple manufacturing process has been separately proposed by the present applicant (Japanese Patent Application No. 11-304729). reference). This semiconductor microactuator is made of a resin material such as polyimide or fluorinated resin, which has high thermal insulation (about 80 times that of silicon dioxide), is easily processed in a liquid state, and has a desired thickness by a semiconductor manufacturing process such as spin coating. The present invention focuses on the feature that a thin film (several μm to several tens μm) can be easily obtained. Hereinafter, the semiconductor microactuator will be described.

FIG. 10 is a partially broken perspective view showing the structure of the semiconductor microactuator, FIG. 11 (a) is a sectional view, and FIG. 11 (b) is a top view.

As shown in the figure, the semiconductor microactuator 1 is joined to a semiconductor substrate 3 made of silicon or the like, which is a hollow and substantially rectangular frame, at four points inside the semiconductor substrate 3 via a heat insulating region 7. And a movable portion 8 separated from the semiconductor substrate 3. This movable part 8
Is a rectangular piece that extends outwardly from each of the four sides of the opening on the upper surface of the central movable element 5 formed in a hollow truncated pyramid shape in which the upper surface is opened in a square shape and the width decreases downward. The flexible region 2 has a substantially cross shape with the movable element 5 interposed therebetween.

The heat insulating region 7 between the semiconductor substrate 3 and the flexible region 2 is filled with a heat insulating material such as a fluorinated resin or polyimide at substantially the same thickness as the flexible region 2. A heating means 6 for heating the flexible region 2 made of impurity diffusion resistance or the like is provided on the surface of the flexible region 2, and the flexible region 2 is provided thereon with an aluminum thin film or a nickel thin film. A thin film 4 having a different coefficient of thermal expansion from that of the silicon constituting the flexible region 2 is provided. here,
The semiconductor substrate 3, the flexible region 2, and the heat insulating region 7 therebetween form a heat insulating structure.

Here, in order to explain the operation of this semiconductor microactuator, as a specific example, as shown in the sectional view of FIG.
m, the thickness is 20 μm, and its constituent material is polyimide (trade name “Photo Nice”, hereinafter referred to as polyimide)
Let us consider the case where is used. Further, the length of the flexible region 2 shown in FIG.
The length of the flexible region 2 is 800 μm, and the width of the flexible region 2 (in the direction parallel to the heat insulating region 7) is 600 μm.

When the heat Q3 escaping from the flexible region 2 to the semiconductor substrate 3 through the heat insulating region 7 is calculated, it follows the formula X shown in the conventional example. Here, the section A3 perpendicular to the direction of the heat flow of the escaped heat Q3 is A3 = (thickness of polyimide) × (width of flexible region) = 20 μm × 600 μm = 1.2 × 10 ⁻⁴ cm. The thermal conductivity of polyimide is 1.17 × 10
⁻³ (W / cm ° C.) and the distance δ from the heat source, that is, the distance between the flexible region 2 and the semiconductor substrate 3 is 30 μm.
The heat Q3 escaping from the flexible region 2 heated to 150 ° C. to the semiconductor substrate 3 is Q3 = 1.17 × 10 ⁻³ (W / cm · ° C.) × (150 ° C.)
/ (30 × 10 ⁻⁴ cm)) × 1.2 × 10 ⁻⁴ (cm ² ) = 4.2 × 10 ⁻³ (W) = 4.2 (mW) As described above, since the movable portion 8 has four flexible regions, the total amount of heat is 16.8 mW. This indicates that the temperature of the flexible region 2 can be maintained at 150 ° C. by inputting the input power of 16.8 mW to the heating means 6, and the power consumption is reduced to 1/40 of that of the conventional example of 660 mW. it can.

Next, the strength of the heat insulating region 7 made of polyimide will be considered. A model of a doubly supported beam structure fixed at both ends shown in FIG. When a load W is applied from below to the center of the beam as shown in FIG.
The shear force and moment force of the beam are shown in FIG.
The result is as shown in FIG. The heat insulating region 7 is shown in FIG.
In FIG. 7A, it is located between the fixed ends 25, 26 at both ends and the beam 27. Therefore, for example, a force applied to the beam 27 when a load W of 1 g is applied to the center of the beam 27 (corresponding to a case where a pressure of 46.7 kPa is applied to the orifice 500 μm in the case of a microvalve) is obtained.

The shear force F applied to the beam is as follows: F = W / 2 = 1.0 × 10 ⁻³ (kgf) /2=0.5×10 ⁻³ (kgf) = 4.9 × 10 ⁻³ (N) And the maximum shear stress Fmax applied to the beam is as follows: Fmax = F / S (S is the cross-sectional area of the beam). Here, beam width b = 600 μm, beam thickness h =
If it is 20 μm, the sectional area S is S = bh = 600 × 10 ⁻⁴ × 20 × 10 ⁻⁴ = 1.2 × 10 ⁻⁴ cm ² . Therefore, the maximum shear stress Fma applied to the beam 27
x is: Fmax = 0.50 × 10 ⁻³ (kgf) /1.2×10 ⁻⁴ (cm ² ) = 4.16 (kgf / cm ² ) = 4.16 × 0.098 (MPa) = 0 .41 (MPa). Next, the maximum stress σmax applied to the beam is determined.
The maximum stress σmax is represented by σmax = Mmax / Z. At this time, Mmax is the maximum moment, and Z is the section modulus. As shown in FIG. 13C, the maximum moment Mmax is Mmax = WL / 8 (L is the length of the beam is 800 μm). Therefore, the maximum moment Mmax is as follows: Mmax = WL / 8 = 1.0 × 10 ^{− 3} (kgf) × 800 × 10 ⁻⁴ (cm) /8=1.0×10 ⁻⁵ (kgf · cm) = 9.8 × 10 ⁻⁵ (N · cm) Moreover, the section modulus Z becomes ^{Z = bh 2/6 = 1} /6 × 600 × 10 -4 × (20 × 10 -4) 2 = 4.0 × 10 -8 (cm 3). Therefore, the maximum stress σmax due to the moment is σmax = Mmax / Z = 1.0 × 10 ⁻⁵ (kgf · cm) /4.0×10 ⁻⁸ (cm ³ ) = 250 (kgf / cm ² ) = 24.5 (MPa). Here, the dimensions of the beam are set to 600
μm and a length of 800 μm.

Since the breaking strength of polyimide is about 30 MPa, a semiconductor microactuator that can withstand a load of about 1 g in the above-mentioned heat insulating region 7 can be realized. Further, the strength of the heat insulating region 7 can be increased. Although not described here, the same effect can be expected with a fluorinated resin.

Here, an example of a method of forming the heat insulating region 7 shown in FIG. 12 will be described with reference to FIG. First, FIG.
As shown in FIG. 3A, a portion corresponding to the heat insulating region on the surface of the semiconductor substrate 17 is etched with KOH or the like to form a groove 1.
5 is formed. Thereafter, as shown in FIG. 14B, a polyimide thin film 16 is spin-coated with a coater or the like to form a groove 15.
Is formed so as to fill the space. Next, as shown in FIG. 14 (c), patterning is performed so that the polyimide thin film 16 is completely removed from the portion where the groove 15 is completely filled by a semiconductor photolithography process or the like, and the other portion is removed. The organic solvent or the like contained in the polyimide is evaporated and solidified. Next, as shown in FIG. 14D, the back surface of the semiconductor substrate 17 is etched by KOH or the like. At this time, 28 is a semiconductor substrate to be a frame portion, and 29 is a flexible region. Through these steps, the heat insulating region 7 shown in FIG. 12 is formed.

As described above, the heat insulating region 7 is made of a resin material such as polyimide or fluorinated resin, which has a high heat insulating property (about 80 times that of silicon dioxide). By making good use of the property that a thin film having a desired thickness (several μm to several tens μm) can be easily obtained by a semiconductor manufacturing process, the heat insulating region 7 between the flexible region 2 and the semiconductor substrate 3 can be easily formed. Since the heat insulating structure is formed within the thickness of the flexible region 2, a heat insulating structure having a higher heat insulating effect and a higher strength than the conventional example can be easily realized by using a semiconductor manufacturing process. Further, as described above, by making the heat insulating region 7 substantially the same thickness as the flexible region 2, the semiconductor substrate 3 and the flexible region 2 are formed.
And the strength of the joint can be increased.

Here, the semiconductor microactuator 1
Will be described. When electric power is applied to the heating means 6, the temperature of the flexible region 2 rises. Since the thin film 4 having a thermal expansion coefficient different from that of the flexible region 2 is formed on the upper portion of the flexible region 2, thermal stress is generated due to a difference in thermal expansion between the two. For example, when a metal thin film of aluminum, nickel, or the like is formed as the thin film 4, the flexible region 2 is bent downward in the figure because the thermal expansion coefficient is larger than that of the silicon constituting the flexible region 2. . Since the movable element 5 is connected to the flexible region 2, the movable element 5 receives the thermal stress of the flexible region 2 and is displaced downward with respect to the semiconductor substrate 3.

In the semiconductor microactuator 1, the central movable element 5 and the four flexible regions 2 around the central movable element 5 form a cross-shaped beam, and the displacement of the movable element 5 is not relative to the semiconductor substrate 3. Rotational displacement results, and a large force can be generated with good displacement control accuracy. Further, the manufacturing process is simple with the above-described configuration, and the device can be driven with high thermal insulation and small size and low power consumption. In addition, since the flexible region 2 is provided with the heating means 6 made of a diffusion resistance or the like for heating the flexible region 2, the semiconductor microactuator 1 can be downsized.

Next, the semiconductor substrate 3 and the flexible region 2
Another example of the heat insulating structure constituted by the heat insulating region 7 will be described. As shown in FIGS. 15A and 15B, the heat insulating structure of the present example includes a semiconductor substrate 3 and a flexible region 2.
The point in which a heat insulating region 10 having a thickness substantially equal to the thickness of the flexible region 2 is formed within the thickness between them is the same as that of FIG. 12, but this heat insulating region 10 has a fluorinated resin or Thermal insulating material region 1 made of a thermal insulating material such as polyimide
1 and a reinforcing region 12 made of a thin film harder than the material forming the heat insulating region 11 such as silicon dioxide below. FIG. 15A is a sectional view, and FIG.
FIG. 16B is a top view, and FIG.
It is Y 'sectional drawing.

As shown in FIG. 16, the specific thickness of the heat insulating region 10 is 20 μm as a whole, the heat insulating material region 11 is 19 μm, and the reinforcing region 12 is 1 μm. Then, as shown in FIG. 15A, the length in the horizontal direction of the heat insulating region 10, ie, the direction from the semiconductor substrate 3 to the flexible region 2, is 30 μm, and the length in the YY ′ direction, ie, the depth direction is It is 600 μm. Here, the strength of the heat insulating region 10 when polyimide is used as the material forming the heat insulating material region 11 and silicon dioxide is used as the material forming the reinforcing region 12 is shown in FIG.
The calculation is performed under the same conditions as in the calculation of the strength of the heat insulating region 7 in.

Assuming that the Young's modulus of each constituent material of the heat insulating region 10 is Ei and the sectional area of the cross section shown in FIG. 16 of each region is Ai, the distance from the bottom surface to the neutral axis is given by the following equation.

[0033]

(Equation 1)

The values obtained for the silicon dioxide constituting the reinforcing region 12 are as follows.

[0035]

(Equation 2)

The values of the polyimide constituting the heat insulating material region 11 are obtained as follows.

[0037]

(Equation 3)

Here, when the distance ηa to the neutral axis is obtained using the above values, the following is obtained.

[0039]

(Equation 4)

Next, the second moments Is and If about the neutral axis of silicon dioxide and polyimide are obtained as follows.

[0041]

(Equation 5)

Here, ηi = η−ηa, that is, ηi indicates the distance from the neutral axis. As described with reference to FIG. 13, when a load of 1 g is applied to the center of the beam having both ends fixed, the maximum moment Mmax applied to the beam is as follows: Mmax = 1.00 × 10 ⁻⁵ (kgf · cm) = 9. 8 × 1.00 × 10 ⁻⁵ × 10 ⁻² (N · m) Calculation of the maximum bending stress σsmax of silicon dioxide is as follows.

[0043]

(Equation 6)

Here, Ii is each of the above second moments Is,
If is shown. Also, the maximum bending stress σ of polyimide
Calculation of fmax is as follows.

[0045]

(Equation 7)

Therefore, the stress applied to the heat insulating material region 11 made of polyimide is about 比 べ as compared with the example shown in FIG. This is apparently equivalent to doubling the intensity. In FIG. 15, the reinforcing region 12 is provided below the heat insulating material region 11, but the same effect can be obtained even in the upper region. Further, when provided on both the upper and lower sides, an effect twice as high as when provided on each of the lower part and the upper part can be obtained.

As described above, the heat insulating region 1 shown in FIG.
An example of a method of forming 0 will be described with reference to FIG. First, FIG.
As shown in FIG. 7A, a portion of the surface of the semiconductor substrate 18 corresponding to the heat insulating region is etched with KOH or the like to form a groove 19. Thereafter, as shown in FIG. 17B, a silicon dioxide thin film 21 is formed on the surface of the semiconductor substrate 18 by thermal oxidation or the like. Except for the surface portion of the groove 19, the silicon dioxide thin film 21 is removed by etching or the like.

Next, as shown in FIG. 17C, a polyimide thin film 22 is spin-coated with a coater or the like to form the groove 19 completely. Further, as shown in FIG. 17D, patterning is performed so that the polyimide thin film 22 in a portion that completely fills the groove 19 by a photolithography process of a semiconductor is left, and other portions are removed, and heated to about 400 ° C. The organic solvent or the like contained in the polyimide is evaporated and solidified. Next, as shown in FIG. 17E, the semiconductor substrate 18 is etched from the back surface with KOH or the like. At this time, 23 is a semiconductor substrate, and 24 is a flexible region. Through these steps, the heat insulating region 10 shown in FIG. 15 is formed.

Next, still another example of the heat insulating structure will be described. In this example, as shown in FIGS. 18 (a) and 18 (b),
Within the thickness between the flexible region 2 separated from the semiconductor substrate 3 and the semiconductor substrate 3, a heat insulating region 20 having substantially the same thickness as the flexible region 2 is formed. In this example, as shown in the top view of FIG. 18B, each of the semiconductor substrate 3 and the flexible region 2 protrudes outside the flexible region 2 in the BB ′ direction and inside the flexible region 2, The semiconductor substrate 3 is formed in a comb blade shape having three comb blades so as to protrude, and a heat insulating region 20 is provided therebetween. B- in FIG.
As shown in FIG. 19, which is a cross-sectional view taken along the line B ′, the flexible region 2, the semiconductor substrate 3, and the heat insulating region 20 are mixed in the direction BB ′. Here, the heat insulating region 20 is made of a fluorinated resin, polyimide, or the like.

In order to calculate the strength of the heat insulating region 20, as a specific example, as shown in FIGS. 18A and 18B, the thickness of the heat insulating region 20 is set to 20 μm, and the thickness in the direction perpendicular to the BB ′ direction. The width is 30 μm. Further, as shown in FIG. 19, the B-
The width in the B ′ direction is 180 μm, and the BB ′ of the heat insulating region 20 is
The width in the direction is 30 μm. The material of the heat insulating region 20 is polyimide, and the semiconductor substrate 3 and the flexible region 2 are made of silicon. For comparison, FIG.
The strength of the heat insulating region 20 is calculated under the same conditions as in the strength calculation of 2.

In the case of a combination structure of silicon and polyimide as shown in FIG. 19, the Young's modulus of the silicon is E _si , the Young's modulus of the polyimide is E _Ph , the second moment of area of the silicon part is I _Si , and the cross section of the polyimide part is two. Assuming that the next moment is I _Ph , the moment M _Si applied to the silicon portion and the moment applied to the polyimide portion are M _Ph , the following relational expression is obtained.

[0052]

(Equation 8)

Therefore, the moment M _{Si of the} silicon part and the moment M _Ph of the polyimide part are represented by:

[0054]

(Equation 9)

Is represented by Therefore, the moment M _max applied to the heat insulating structure is

[0056]

(Equation 10)

Is as follows.

The moment M _{Ph of the} polyimide part is

[0059]

[Equation 11]

Is as follows. Similarly, the moment M _{Si of the} silicon portion is as follows.

[0061]

(Equation 12)

Here, respective values relating to the silicon portion and the polyimide portion are calculated. Young's modulus of silicon E _Si = 0.19
× 10 ¹² (N / m ² ) = 1.9 × 10 ¹² (dyne / c
m ² )

[0063]

(Equation 13)

Therefore, E _Si · I _Si = 1.93 × 10
⁶ (kgf / cm ² ) × 3.6 × 10 ⁻¹¹ (cm ⁴ ) = 6.
94 × 10 ⁻⁵ (kgf · cm ² ) = 6.8 × 10 ⁻⁴ N ·
cm ² . The Young's modulus E _{Ph of} polyimide is 500MP
a

[0065]

[Equation 14]

Therefore, E _Ph · I _Ph = 5.10 × 10
³ (kgf / cm ² ) × 4 × 10 ⁻¹² (cm ⁴ ) = 2.04
× 10 ⁻⁸ (kgf · cm ² ) = 2.00 × 10 ⁻⁷ (N ·
cm ² ).

Here, the moment MPh applied to the polyimide portion is as follows.

[0068]

(Equation 15)

Here, M _Ph = 2.93 × 10 ⁻⁹ (kgf
Cm) = 2.87 × 10 ⁻⁸ (N · cm).

Similarly, the moment M _Si applied to the silicon portion is as follows.

[0071]

(Equation 16)

Here, M _Si = 9.999 × 10 ⁻⁶ (kgf
Cm) = 9.79 × 10 ⁻⁵ (N · cm).

Therefore, the maximum stress σ applied to the polyimide part
_Ph is as follows.

[0074]

[Equation 17]

Here, Za is a section modulus. Further, the maximum stress σSi applied to the silicon portion is obtained as follows.

[0076]

(Equation 18)

Here, Zb is a section modulus.

Therefore, the stress applied to the heat insulating region made of polyimide is about 1/30 as compared with the example shown in FIG.
It becomes 0. This is apparently equivalent to a 300-fold increase in strength. FIG. 18 illustrates a case where the semiconductor substrate 3 and the flexible region 2 form three comb blades, but the present invention is not limited to this. At least two or more comb blade structures are used. By doing so, a similar effect can be obtained.

In the semiconductor microactuator shown in FIGS. 10 to 12, the flexible region 2 and the movable element 5
Are integrated so that the movable element 5 is connected to the flexible region 2. However, as shown in FIG. 20, the movable element 5a is separated from the flexible region 2a, and the movable element 5a is A configuration may be adopted in which a heat insulating region 7b filled with a resin such as polyimide is formed between the region 2a and the region 2a. The point that the heat insulating region 7a is formed between the semiconductor substrate 3a and the flexible region 2a is the same as in FIGS.

The semiconductor substrate 3a has the movable element 5
a, the flexible region 2a has a larger heat capacity than the semiconductor substrate 3a.
Even in the structure in which the heat insulating region 7a is provided between the flexible region 2a and the heat insulating region 7a, the movable element 5a is separated from the flexible region 2a to reduce the heat insulating region 7b. With this structure, the thermal insulation is further enhanced, and the flexible region 2a and the thin film 4a can be effectively heated by the diffusion resistor 6a serving as a heating unit. Therefore, power consumption can be reduced.

Referring to FIG. A protective thin film 9 is provided on each upper surface of the semiconductor substrate 3a, the flexible region 2a, and the movable element 5a.
b, and a protective thin film 9a is provided on a part of the upper surface thereof. The flexible region 2a is provided on the surface of the flexible region 2a.
Resistance 6a as heating means (heater) for heating
One end is connected to the diffusion resistor 6a, and the heat insulating region 7 is formed on the protective thin film 9a on the flexible region 2a.
a through the lower surface of the protective thin film 9 on the upper part of the semiconductor substrate 3a.
An aluminum wiring 13a connected to, for example, an electrode pad (not shown) provided on a is formed.

A thin film 4a having a different coefficient of thermal expansion from that of the silicon constituting the flexible region 2a is provided on the upper surface of the protective thin film 9a on the flexible region 2a.
When electric power is applied to the diffusion resistor 6a through the gate, the temperature of the diffusion resistor 6a rises, and the silicon of the flexible region 2 and the thin film 4a
A thermal stress is generated due to the difference in thermal expansion of the movable element 5a, and the flexible region 2a is displaced, and the movable element 5a is displaced.

FIG. 21 schematically shows the state of formation of the aluminum wiring 13a, from the upper part of the flexible region 2a to the side of the heat insulating region 7a and the lower surface which is one end surface of the flexible region 2a in the thickness direction. The portion 7P is formed over the upper portion of the semiconductor substrate 3a via the side portion. In FIG. 21, illustration of the protective thin film is omitted.

A manufacturing process of the semiconductor microactuator configured as shown in FIG. 20 will be described with reference to FIGS.

First, a silicon oxide film 80a is formed on both surfaces of a single crystal silicon substrate 80 by thermal oxidation or the like, and a photoresist patterned into a predetermined shape is used as a mask.
The opening 80b is formed by etching the silicon oxide film 80a provided on the back surface of the single crystal silicon substrate 80.
Is formed, and the photoresist is removed by plasma ashing or the like. A gap 80c is formed by etching the formed opening 80b with a potassium hydroxide aqueous solution (hereinafter, referred to as a KOH aqueous solution) or the like (FIG. 22).
(A)). At this time, in addition to the KOH aqueous solution, TMAH (tetramethyl ammonium hydroxide solution), humanrazine aqueous solution, or the like may be used. The same applies to the KOH aqueous solution described below.

Next, after the entire surface of the silicon oxide film 80a is removed, boron or the like is deposited and thermally diffused, and a diffusion resistor 6 serving as a heater is formed on the surface of the single crystal silicon substrate 80.
a is formed. Subsequently, a silicon oxide film 81b is formed on both surfaces of the single crystal silicon substrate 80 by thermal oxidation or the like, and a silicon nitride film 81a is formed on each silicon oxide film 81b by low-pressure CVD (FIG. 22B). .

Using the photoresist patterned in a predetermined shape as a mask, the silicon oxide film 81b and the silicon nitride film 81a are etched to form an opening 82, and the photoresist is removed by plasma ashing or the like (FIG. 22 (c)).

Next, the opening 8 of the single crystal silicon substrate 80
The movable element 5a and the flexible region 2a are formed by etching 2 with a KOH aqueous solution or the like. At this time, in order to obtain the desired thickness of the movable element 5a and the thickness of the flexible region 2a, a time difference may be provided between the start of etching from each surface of the single crystal silicon substrate 80. Thereafter, the single crystal silicon substrate 80 is etched to form the heat insulating region 7.
A groove 83a, 83b for forming a, 7b is formed. The grooves 83a and 83b are for embedding an organic material such as polyimide in a later step, and have a bottom thickness of 10 μm.
Etching is performed to a thickness of about m (FIG. 22).
(D)).

Subsequently, the movable element 5a, the flexible region 2
The surface of the substrate etched to form a is oxidized to form a protective film 84 for plating the substrate (FIG. 22E).

Then, aluminum is formed on the upper surface of the single crystal silicon substrate 80 by sputtering or EB vapor deposition to form an aluminum wiring 13a serving as an electric wiring connected to the diffusion resistor 6a (FIG. 23A).

Next, an organic substance 85 such as polyimide is buried in the grooves 83a and 83b (FIG. 23B). In this manner, a structure in which the aluminum wiring 13a is formed on the lower surface of the organic substance 85 is obtained. Here, an organic material such as polyimide 8
5 is formed only in a predetermined portion using a semiconductor lithography process.

Then, a metal pattern of a predetermined shape is formed by plating or the like on the silicon nitride film 81a over the flexible region 2a.
(Protective thin film 9a in FIG. 20) to form thin film 4a (FIG. 23 (c)). Thereby, the flexible region 2a and the thin film 4a
Thus, a bimetal structure as a driving source of the semiconductor microactuator is obtained.

Next, the flexible region 2a is etched from the back surface of the flexible region 2a by RIE or the like so that the flexible region 2a is
0 (semiconductor substrate 3 in FIG. 20) and movable element 5a (FIG. 23D). This allows
The movable element 5a, the flexible region 2a, and the semiconductor substrate 3a are thermally insulated from each other, and have thermal insulation regions 7a and 7b provided therebetween.

Thus, the semiconductor microactuator 87 is manufactured, and the semiconductor microactuator 8 is manufactured.
The semiconductor microvalve using the semiconductor microactuator as shown in FIG. 24 is manufactured by bonding the glass substrate 7 and a glass substrate 88 formed in a predetermined mold by anodic bonding or the like. After that, the diaphragm portion other than the flexible region 2a is etched by RIE or the like. (Not shown) FIG.
The aluminum wiring 13a at 0 is provided on the lower surface of the heat insulating region 7a as shown in FIG. 21. However, as shown in FIG. It may be provided inside the heat insulating region 7a.

In order to form the aluminum wiring 13b in this manner, after the step of forming the protective film 84 shown in FIG. 22E, the groove 83a formed in the step of FIG.
In the step of embedding the organic substance 85 such as polyimide shown in FIG.
The step of forming the aluminum wiring shown in FIG.
The groove 83a may be filled by the filling step shown in FIG. The other steps are as shown in FIGS. 22 and 23, and thus the description thereof is omitted.

Since the aluminum wiring 13b is formed inside the heat insulating region 7a as described above, the aluminum wiring 13b has an effect of protecting aluminum in a later etching step and the like, and a highly reliable wiring structure can be realized.

In the above wiring structure, an aluminum wiring 13c may be provided on the upper surface of heat insulating region 7a as shown in FIG.

In order to form the aluminum wiring 13c as described above, after the step of forming the protective film 84 shown in FIG. 22E, the groove 83a formed in the step of FIG.
The polyimide may be buried in the step of burying the organic substance 85 such as polyimide shown in FIG. 23B, and then the aluminum wiring may be formed on the upper surface of the polyimide in the step of forming the aluminum wiring shown in FIG. The other steps are as shown in FIGS. 22 and 23, and thus the description thereof is omitted.

As described above, since the aluminum wiring 13c is formed on the upper surface of the heat insulating region 7a, that is, the flexible region 2a, the heat insulating region 7a, and the semiconductor substrate 3a are formed on the same surface. As compared with the case where the aluminum wiring is provided inside or on the lower surface of the heat insulating region 7a,
The step of the aluminum wiring is reduced, and there is an effect of preventing disconnection of the aluminum wiring.

Next, another semiconductor microactuator will be described with reference to the perspective view of FIG. The semiconductor microactuator 41 includes a semiconductor substrate 43 serving as a frame made of silicon or the like, and a heat insulating region 47 inside the semiconductor substrate 43.
And a movable part 48 separated from the semiconductor substrate 43 joined through the substrate. The movable portion 48 is provided with a hollow movable element 45 protruding downward at one end.
And a square-shaped flexible region 42 formed in connection with the movable element 45.

A heat insulating region 47 having the same thickness as that of the flexible region 42 is provided within the thickness between the semiconductor substrate 43 and the end of the flexible region 42 where the movable element 45 is not provided. . The flexible region 42 has a cantilever structure with the semiconductor substrate 43 as a fixed end. This heat insulating region 47 is made of a fluorinated resin, polyimide or the like. A heating means 46 made of impurity diffusion resistance or the like is provided on the surface of the flexible region 42, and a thin film 44 having a thermal expansion coefficient different from that of silicon, such as an aluminum thin film or a nickel thin film, is formed above the flexible region 42. ing. In addition, an electrode pad 49 of the heating means 46 is provided on the surface of the semiconductor substrate 43. Here, the semiconductor substrate 43, the flexible region 42, and the heat insulating region 47 form a heat insulating structure.

The operation of the semiconductor microactuator 41 thus configured will be described. When power is applied to the heating means 46, the temperature of the flexible region 42 increases. Since a thin film 44 having a different thermal expansion coefficient from that of the flexible region 42 is formed above the flexible region 42, thermal stress is generated in the flexible region 42 due to the difference in the thermal expansion coefficient. For example, when the thin film 44 is a metal thin film of aluminum, nickel, or the like, the flexible region 42 is bent downward in FIG.

Therefore, the movable element 45 connected to the flexible region 42 receives the thermal stress of the flexible region 42 and is displaced downward with respect to the semiconductor substrate 43. The displacement in this case includes rotation in the vertical direction with respect to the semiconductor substrate 43. By forming the flexible region 42 in a cantilever structure in this manner, the flexibility of the flexible region 42 can be increased, the bending of the flexible region 42 during heating increases, and the displacement of the movable element 45 increases. Great power is obtained. Here, the heat insulating structure is shown in FIG.
2, any of those shown in FIGS. 15 and 18 may be used, and a semiconductor microactuator having the same effect as that of the above-described heat insulating structure can be obtained.

An object of the present invention is to provide a semiconductor microactuator capable of increasing the displacement of a movable part (a movable element thereof) in addition to the high thermal insulation efficiency and a simple manufacturing process obtained in this way. .

[0105]

According to a first aspect of the present invention, there is provided a semiconductor microactuator having at least one flexible region which is displaced in response to a temperature change and one of the flexible regions. A movable portion having a thin film formed on a surface thereof; and a semiconductor substrate supporting a flexible region side of the movable portion, wherein a heat insulating region is provided between the flexible region and the semiconductor substrate. The thickness of the thin film on the side of the heat insulating region is increased.

In this configuration, there is a difference in the amount of displacement due to thermal expansion between the heat insulating region side and the opposite side in the flexible region. (The movable element thereof) can be increased in displacement.

In the semiconductor microactuator according to the first aspect, the thin film may be provided only on the side of the heat insulating region. Even with this structure, it is possible to increase the displacement of the movable part.

Further, in the semiconductor microactuator according to the first aspect, the thin film may have a structure in which the thin film is formed in a step shape so as to be thicker on the side of the heat insulating region. Even with this structure, it is possible to increase the displacement of the movable part.

Further, in the semiconductor microactuator according to the present invention, the thin film may be formed so as to gradually increase in thickness as approaching the heat insulating region side. Even with this structure, it is possible to increase the displacement of the movable part.

[0110]

FIG. 1 is a sectional view of a semiconductor microactuator according to a first embodiment of the present invention. FIG. 1 shows a cross section corresponding to FIG.

The semiconductor microactuator 1A shown in FIG. 1 has four flexible regions 2 which are displaced in response to a change in temperature and a thin film 4A formed on each upper surface of these flexible regions 2.
And a frame-shaped semiconductor substrate 3 supporting each flexible region 2 side of the movable region 8. A heat insulating region is provided between each flexible region 2 and the semiconductor substrate 3. 7 are provided, and the thickness of the thin film 4A on each heat insulating region 7 side is increased. However, as for other specific structures, it goes without saying that the same structure as that of the semiconductor microactuator described in Japanese Patent Application No. 11-304729 described above is employed according to various usage forms.

Here, the thin film 4A is provided on a part of the upper surface of the flexible region 2 located on the side of the heat insulating region 7, and is different from the thin film 4 provided on almost the entire upper surface of the flexible region 2 shown in FIG. . In this manner, the thin film 4A substantially on each heat insulating region 7 side
When the thickness of the thin film 4A is increased, a difference occurs in a displacement amount due to thermal expansion between the heat insulating region 7 side and the opposite side, so that only the portion where the thin film 4A is in contact does not protrude upward. The displacement can be increased.

FIG. 2 is a diagram showing a difference in displacement of the movable element 5 generated between the semiconductor microactuators 1A and 1 when the thin films 4A and 4 have the same volume. However, FIG. 2 shows a simulation result using the finite element method. From FIG. 2, when the thin films 4A and 4 have the same volume,
It can be seen that the displacement amount of the movable element 5 is larger in the semiconductor microactuator 1A having the thin film 4A provided on a part of the upper surface of the flexible region 2 located on the heat insulating region 7 side.

As described above, since the range of the displacement of the movable element 5 and the force received from the movable element 5 is widened, it is possible to meet various requests that require a larger displacement of the movable element 5 or a larger force from the movable element 5. Will be able to

In the first embodiment, the thin film provided on a part of the upper surface of the flexible region located on the side of the heat insulating region is applied to the semiconductor microactuator 1 shown in FIG. 10, but is not limited to this. Instead, a thin film provided on a part of the upper surface of the flexible region located on the heat insulating region side may be applied to the semiconductor microactuator 41 shown in FIG. FIG. 3 shows an example of this configuration. The semiconductor microactuator 41A shown in the figure includes a movable region 48 having a flexible region 42 displaced in accordance with a temperature change and a thin film 44A formed on the upper surface of the flexible region 42; Frame-shaped semiconductor substrate 4 supporting flexible region 42 side
3, a heat insulating region 47 is provided between the flexible region 42 and the semiconductor substrate 43, and the thin film 44 on the heat insulating region 47 side is provided.
A is made thicker. That is, as shown in FIG.
By providing the thin film 44A on a part of the upper surface of the flexible region 42 located on the side of the heat insulating region 47, the movable element 45
Can be increased vertically. The thin film 44
According to A, the length of the heating means 46 in the left-right direction may be changed to be equal to or less than the length of the joint surface between the flexible region 42 and the thin film 44A.

FIG. 4 is a sectional view of a semiconductor microactuator according to a second embodiment of the present invention. However, FIG.
Shows a cross section corresponding to FIG.

The semiconductor microactuator 1B shown in FIG. 4 has four flexible regions 2 which are displaced in response to a change in temperature and a thin film 4B formed on each upper surface of these flexible regions 2.
And a frame-shaped semiconductor substrate 3 supporting each flexible region 2 side of the movable region 8. A heat insulating region is provided between each flexible region 2 and the semiconductor substrate 3. 7 are provided, and the thickness of the thin film 4B on the side of each heat insulating region 7 is increased.

Here, the thin film 4B is formed in a three-layered step shape so that the heat insulating region 7 becomes thicker, and the thin film 4B is provided with a uniform thickness over substantially the entire upper surface of the flexible region 2 shown in FIG. Different. Thus, the thin film 4 on each heat insulating region 7 side
When the thickness of B is increased, the amount of displacement due to thermal expansion is different between the heat insulating region 7 side and the opposite side, so that only the portion where the thin film 4B is in contact is not displaced upwardly. The vertical displacement can be increased.

As a result, the range of the displacement of the movable element 5 and the force received from the movable element 5 is widened, so that various requests that require a larger displacement of the movable element 5 or a larger force from the movable element 5 can be satisfied. Will be able to Further, processing for increasing the thickness is easy.

In the second embodiment, the semiconductor microactuator 1 shown in FIG. 10 employs a three-layered stepwise thin film so that the heat insulating region side becomes thicker. However, the present invention is not limited to this. Instead of the semiconductor microactuator 41 shown in FIG. 27, a three-layered thin film formed in a stepwise manner so that the heat insulating region side is thicker may be applied. FIG. 5 shows an example of this configuration. The semiconductor micro-actuator 41B shown in this figure has a movable region 48 having a flexible region 42 displaced in accordance with a temperature change and a thin film 44B formed on the upper surface of the flexible region 42; Frame-shaped semiconductor substrate 4 supporting flexible region 42 side
3, a heat insulating region 47 is provided between the flexible region 42 and the semiconductor substrate 43, and the thin film 44 on the heat insulating region 47 side is provided.
B is made thicker. That is, as shown in FIG.
If the three-layered thin film 44B is formed on the upper surface of the flexible region 42 so that the thickness of the heat insulating region 47 is increased, the vertical displacement of the movable element 45 can be increased as described above.

FIG. 6 is a sectional view of a semiconductor microactuator according to the third embodiment of the present invention. However, FIG.
Shows a cross section corresponding to FIG.

The semiconductor microactuator 1C shown in FIG. 6 has four flexible regions 2 which are displaced in response to a change in temperature and a thin film 4C formed on each upper surface of these flexible regions 2.
And a frame-shaped semiconductor substrate 3 supporting each flexible region 2 side of the movable region 8. A heat insulating region is provided between each flexible region 2 and the semiconductor substrate 3. 7 are provided, and the thickness of the thin film 4C on each side of the heat insulating region 7 is increased.

Here, the thin film 4C is formed so as to gradually increase in thickness as approaching the heat insulating region 7, and is different from the thin film 4 provided with a uniform thickness on almost the entire upper surface of the flexible region 2 shown in FIG. I do. As described above, when the thickness of the thin film 4C on the side of each heat insulating region 7 is increased, a difference occurs in the amount of displacement due to thermal expansion between the side of the heat insulating region 7 and the opposite side. It is no longer displaced convexly, and the vertical displacement of the movable element 5 can be increased.

As a result, the range of the displacement of the movable element 5 and the force received from the movable element 5 is widened, so that various requests that require a larger displacement of the movable element 5 or a larger force from the movable element 5 can be satisfied. Will be able to In addition, when the movement of the movable element 5 is large, the possibility that the thin film 4C peels off from the movable element 5 side is reduced.

In the third embodiment, the semiconductor microactuator 1 shown in FIG. 10 is applied with a thin film which is formed so as to gradually increase in thickness as approaching the heat insulating region. However, the present invention is not limited to this. 27 may be applied to the semiconductor micro-actuator 41 shown in FIG. FIG. 7 shows an example of this configuration. The semiconductor microactuator 41C shown in this figure has a movable region 48 having a flexible region 42 displaced in accordance with a temperature change and a thin film 44C formed on the upper surface of the flexible region 42.
And a frame-shaped semiconductor substrate 43 supporting the movable region 48 on the flexible region 42 side. A heat insulating region 47 is provided between the flexible region 42 and the semiconductor substrate 43, and the heat insulating region 4
The thickness of the thin film 44C on the seventh side is increased. That is, FIG.
As shown in FIG. 7, a thin film 44C formed in a shape that gradually becomes thicker as approaching the heat insulating region 47 side is
If provided on the upper surface, the vertical displacement of the movable element 45 can be increased as described above.

[0126]

As is apparent from the above description, according to the first aspect of the present invention, at least one flexible region which is displaced in accordance with a temperature change and is formed on one surface of the flexible region. A movable portion having a thin film, and a semiconductor substrate supporting the flexible region side of the movable portion, a heat insulating region is provided between the flexible region and the semiconductor substrate,
Since the thickness of the thin film on the side of the heat insulating region is increased, the displacement of (the movable element of) the movable portion can be increased.

According to the second aspect of the present invention, in the semiconductor microactuator according to the first aspect, the thin film is provided only on the side of the heat insulating region. Even in this structure, the displacement of the movable portion is increased. Becomes possible.

According to the third aspect of the present invention, in the semiconductor microactuator according to the first aspect, the thin film is formed in a step-like shape so that the thickness of the heat insulating region is increased. The displacement of the part can be increased.

According to the fourth aspect of the present invention, in the semiconductor microactuator according to the first aspect, the thin film is formed in a shape that gradually becomes thicker as approaching the heat insulating region side. Thus, the displacement of the movable part can be increased.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor microactuator according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a difference in displacement of a movable element.

3 is a sectional view of another semiconductor microactuator to which the thin film of FIG. 1 is applied.

FIG. 4 is a sectional view of a semiconductor microactuator according to a second embodiment of the present invention.

FIG. 5 is a sectional view of another semiconductor microactuator to which the thin film of FIG. 4 is applied.

FIG. 6 is a sectional view of a semiconductor microactuator according to a third embodiment of the present invention.

FIG. 7 is a sectional view of another semiconductor microactuator to which the thin film of FIG. 5 is applied.

FIG. 8 is a top view showing the structure of a conventional semiconductor microactuator.

FIG. 9 is a cross-sectional view showing a structure of a conventional semiconductor microactuator.

FIG. 10 is a partially broken perspective view showing the structure of a semiconductor microactuator described in Japanese Patent Application No. 11-304729.

FIGS. 11A and 11B are a cross-sectional view and a top view, respectively, of the semiconductor microactuator of FIG.

FIG. 12 is a sectional view showing the structure of the heat insulating structure shown in FIGS. 10 and 11;

FIG. 13 shows a structural model used to determine the strength of the heat insulating structure shown in FIGS. 10 and 12,
(A) is a schematic diagram, (b) is a distribution diagram of a shearing force, and (c) is a distribution diagram of a moment.

14 (a) to (d) are all FIGS. 10 and 11
FIG. 7 is a cross-sectional view showing a manufacturing process of the heat insulating structure shown in FIG.

15A and 15B show the structure of another heat insulating structure described in Japanese Patent Application No. 11-304729, wherein FIG. 15A is a cross-sectional view and FIG. 15B is a top view.

FIG. 16 is a cross-sectional view of the heat insulating structure shown in FIG.
It is sectional drawing cut | disconnected by.

17 (a) to 17 (e) are cross-sectional views showing the steps of manufacturing the heat insulating structure shown in FIG.

18 shows the structure of still another heat insulating structure described in Japanese Patent Application No. 11-304729, in which (a) is a cross-sectional view and (b) is a top view.

FIG. 19 is a cross-sectional view of the heat insulating structure shown in FIG.
It is sectional drawing cut | disconnected by.

FIG. 20 is a sectional view showing another structure of the semiconductor microactuator described in Japanese Patent Application No. 11-304729.

FIG. 21 is a sectional view showing a structure of an aluminum wiring in the semiconductor microactuator according to the embodiment.

FIGS. 22A to 22E are cross-sectional views illustrating a method for manufacturing the semiconductor microactuator according to the first embodiment. FIGS.

FIGS. 23A to 23D are views showing a method for manufacturing the semiconductor microactuator according to the embodiment, and FIGS. 23A to 23D are cross-sectional views.

FIG. 24 is a sectional view showing a structure of a semiconductor microvalve using the semiconductor microactuator according to the embodiment.

FIG. 25 is a sectional view showing another structure of the aluminum wiring in the semiconductor microactuator described in Japanese Patent Application No. 11-304729.

FIG. 26 is a sectional view showing still another structure of the aluminum wiring in the semiconductor microactuator described in Japanese Patent Application No. 11-304729.

FIG. 27 is a partially broken perspective view showing the structure of a semiconductor microactuator described in Japanese Patent Application No. 11-304729.

[Explanation of symbols]

Reference Signs List 1A, 1B, 1C semiconductor microactuator 2 flexible region 3 semiconductor substrate 4A, 4B, 4C thin film 7 heat insulating region 8 movable portion 41A, 41B, 41C semiconductor microactuator 42 flexible region 43 semiconductor substrate 44a, 44B, 44C thin film 47 Thermal insulation area 48 Moving parts

[Procedure amendment]

[Submission Date] January 11, 2000 (2000.1.1)
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Explanation of sign

[Correction method] Change

[Correction contents]

[Description of symbols] 1A, 1B, 1C semiconductor microactuator 2 flexible area 3 semiconductor substrate 4A, 4B, 4C thin film 7 heat insulating region 8 movable portion 41A, 41B, 41C semiconductor microactuator 42 flexible area 43 a semiconductor substrate 44 A , 44B, 44C Thin film 47 Thermal insulation area 48 Movable part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kimiaki Saito 1048 Kadoma Kadoma, Osaka Pref.Matsushita Electric Works, Ltd. 72) Inventor Yoshiaki Tomonari 1048 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works Co., Ltd. No. 1048, Kadoma, Kadoma, Kadoma, Matsushita Electric Works Co., Ltd. (72) Inventor Masayu Kamakura 1048, Kadoma, Kadoma, Kadoma, Osaka Pref. No. Matsushita Electric Works Co., Ltd.

Claims (4)

[Claims] At least one member that is displaced in response to a temperature change
A movable portion having two flexible regions and a thin film formed on one surface of the flexible region; and a semiconductor substrate supporting the flexible region side of the movable portion. A semiconductor microactuator comprising: a heat insulating region provided between the semiconductor substrate and the semiconductor substrate; 2. The semiconductor microactuator according to claim 1, wherein the thin film is provided only on the heat insulating region side. 3. The semiconductor microactuator according to claim 1, wherein the thin film is formed in a step shape so that the thickness of the heat insulating region is increased. 4. The semiconductor microactuator according to claim 1, wherein the thin film is formed to have a thickness that gradually increases as approaching the heat insulating region side.