JPH10270718A - Manufacture of semiconductor inertia sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high sensitivity high accuracy semiconductor inertia sensor with the low cost that eliminates the need for sticking of a wafer and laser machining which is suitable for high volume production and is low in parasitic capacitance, and in which easy and strong anode junction is applicable. SOLUTION: An oxide film 20 having an opening 20a is formed on one surface of a silicon wafer 21, and a polysilicon layer 22 is formed on a remaining one surface of the wafer 21 and on the film 20. The layer 22 on the film 20 is selectively etched and removed to form a plurality of polysilicon areas 22a, 22b, 22c separated from each other. A structure 23 including these areas is joined with a glass substrate 10 including a recess 11. The wafer 21 and the layer 22 are etched and removed and then the film 20 is removed, whereby a semiconductor inertia sensor 30 includes fixed electrodes 27, 28 comprising polysilicon joined with the glass substrate 10, and a movable electrode 26 comprising polysilicon floating above the substrate 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor inertial sensor suitable for a capacitance type acceleration sensor, angular velocity sensor, and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as this kind of semiconductor inertial sensor, a resonance angular velocity sensor having a structure of a glass substrate and single crystal silicon has been proposed (M. Hashimoto et al.,
"Silicon Resonant Angular Rate Sensor", Techinica
l Digest of the 12th Sensor Symposium, pp.163-166
(1994)). This sensor has a movable electrode with a tuning fork structure that floats on both sides with a torsion bar. This movable electrode is excited by electromagnetic drive. When the angular velocity acts, a Coriolis force is generated on the movable electrode, and the movable electrode causes torsional vibration around the torsion bar to resonate. The sensor detects an angular velocity that acts due to a change in capacitance between the movable electrode and the detection electrode due to resonance of the movable electrode. When this sensor is manufactured, a structure such as a movable electrode portion is manufactured by etching a single crystal silicon substrate having a thickness of about 200 μm and having a crystal orientation of (110) perpendicular to the substrate surface. In order to vertically etch this relatively thick silicon substrate, anisotropic dry etching using SF ₆ gas is performed, or after drilling a YAG laser at the corner of the base of the torsion bar to the movable electrode portion, ,
Wet etching is performed with KOH or the like. The etched silicon substrate is integrated with the glass substrate by anodic bonding.

As another semiconductor inertial sensor, after a sacrificial layer is patterned on a silicon substrate by etching,
A micro-gyro (K. Tanaka et al., "A
micromachined vibrating gyroscope ", Sensors and A
ctuators A 50, pp. 111-115 (1995)). This microgyro has a structure using a so-called surface micromachining technology. In particular,
Forming a detection electrode by impurity diffusion on a silicon substrate,
After forming and patterning a phosphate glass film serving as a sacrificial layer thereon, a polysilicon film is formed, and a process such as vertical etching is performed to form a structure. Finally, by removing the sacrificial layer by etching, the movable electrode portion is cut off to create a gap with respect to the detection electrode, and the movable electrode is brought into a floating state.

As another semiconductor inertial sensor, a method of manufacturing a vibration type semiconductor element having a structure of a glass substrate and single crystal silicon has been disclosed (JP-A-7-28342).
0). In this manufacturing method, a movable electrode portion and a fixed electrode portion are processed on one of two wafers bonded via an etch stop layer, and the processed wafer is bonded as a bonding surface. After the wafer is anodically bonded to the glass substrate, the unprocessed wafer is removed, and then the etch stop layer is removed. As another semiconductor inertial sensor, a gyroscope composed of a glass substrate and single-crystal silicon has been proposed (J. Bernstein et al., "A Micromachined C
omb-Drive Tuning Fork Rate Gyroscope ", IEEE MEMS ''
93 Proceeding, pp.143-148 (1993)). This gyroscope is a bonding surface between a glass substrate on which a detection electrode is formed, and a single crystal silicon substrate on which a movable electrode, a fixed electrode, and the like are formed by performing high-concentration boron diffusion after etching, and then performing bonding. And then etching is performed to remove portions of the silicon substrate where boron is not diffused.

[0005]

The above-mentioned conventional techniques for manufacturing a sensor have the following disadvantages. In the method of manufacturing the resonance angular velocity sensor described above, the silicon active portion which should be a structure floating with respect to the glass substrate sometimes adheres to the glass substrate due to electrostatic attraction during anodic bonding and does not become a movable electrode. In order to prevent this sticking, the movable electrode and the detection electrode are short-circuited and anodic-bonded in a state where electrostatic force does not work, and then the short-circuited electrodes are separated using a laser. In addition, it is necessary to perform laser-assisted etching after bonding to a glass substrate to form an island-shaped fixed electrode. These laser processes are extremely complicated and unsuitable for mass production of sensors.

[0006] In the micro gyro, since a silicon wafer is used as a substrate, the parasitic capacitance of the sensor is large, and it is difficult to increase sensitivity and accuracy. In the method of manufacturing a vibration-type semiconductor device, the anodic bonding between the glass substrate and the structure composed of the two wafers bonded together via the etch stop layer is performed. There is a problem that the flow is hindered by the etch stop layer, which is an insulating film, and easily affects the bonding process and the bonding state of the substrate.

Further, in the method of manufacturing a gyroscope, since the entire structure is formed by using a portion in which boron is diffused as an etch stop portion, when the etch stop effect is incomplete, the thickness of the movable electrode or the fixed electrode is over-etched. However, there was a problem that the dimensional accuracy was poor.
An object of the present invention is to provide a method of manufacturing a low-cost semiconductor inertial sensor which does not require laser processing and is suitable for mass production. Another object of the present invention is to provide a method of manufacturing a semiconductor inertial sensor with low parasitic capacitance, high sensitivity and high accuracy. Another object of the present invention is to provide a method of manufacturing a semiconductor inertial sensor that can easily perform anodic bonding between a substrate including an etch stop layer and a glass substrate and obtain a strong bonding strength.

It is still another object of the present invention to provide a method for manufacturing a semiconductor inertial sensor having excellent dimensional accuracy.

[0009]

The invention according to claim 1 is
As shown in FIG. 1, a step of forming a recess 11 in a glass substrate 10 and an opening 20 a on one side of a silicon wafer 21.
20 that can be etched without eroding silicon
Forming a polysilicon layer 2 on the remaining one surface of the silicon wafer 21 and the film 20 including the opening 20a.
2 and the film 2 including the opening 20a.
A plurality of polysilicon regions 22a and 22 separated from each other by selectively etching away the polysilicon layer 22 on
b, 22c and the polysilicon region 22
a, 22b, 22c, a film 20, a silicon wafer 21, and a structure 23 composed of a polysilicon layer 22 are placed through the polysilicon region portions 22a, 22c such that the polysilicon region 22b faces the concave portion 11. Glass substrate 1
0, a step of etching and removing the silicon wafer 21 and the polysilicon layer 22 using the film 20 as an etch stop layer, and a step of removing the film 20 to form a pair of fixing members made of polysilicon bonded to the glass substrate 10. Obtaining a semiconductor inertial sensor 30 having electrodes 27 and 28 and a movable electrode 26 made of polysilicon sandwiched between the pair of fixed electrodes 27 and 28 and floating above the glass substrate 10. It is.

As shown in FIG. 4, the invention according to claim 2 includes a step of forming a recess 11 in a glass substrate 10, a step of forming a detection electrode 12 on the bottom surface of the recess 11 of the glass substrate 10, and a step of forming a silicon wafer. Forming an etchable film 20 without erosion of silicon having an opening 20a on one surface of the silicon wafer 21; and forming a polysilicon layer 22 on the remaining one surface of the silicon wafer 21 and the film 20 including the opening 20a.
And a film 20 including an opening 20a.
A plurality of polysilicon regions 22a, 22 separated from each other by selectively etching away the upper polysilicon layer 22.
b, 22c and the polysilicon region 22
a, 22b, 22c, a film 20, a silicon wafer 21, and a structure 23 composed of a polysilicon layer 22 are connected to each other through a part 22a, 22c of the polysilicon region so that a part 22b of the polysilicon region faces the detection electrode 12. Bonding the silicon wafer 21 and the polysilicon layer 22 to the glass substrate 10 by etching using the film 20 as an etch stop layer, and removing the film 20 to face the detection electrode 12 on the glass substrate 10. And obtaining a semiconductor inertial sensor 40 having a movable electrode 26 made of polysilicon.

According to a third aspect of the present invention, as shown in FIG. 5, a step of forming a concave portion 11 in a glass substrate 10, a step of forming a detection electrode 12 on the bottom surface of the concave portion 11 of the glass substrate 10, Forming an etchable film 20 without erosion of silicon having an opening 20a on one surface of the silicon wafer 21; and forming a polysilicon layer 22 on the remaining one surface of the silicon wafer 21 and the film 20 including the opening 20a.
And a film 20 including an opening 20a.
A plurality of polysilicon regions 22a, 22 separated from each other by selectively etching away the upper polysilicon layer 22.
b, 22c and the polysilicon region 22
a, 22b, 22c, a film 20, a silicon wafer 21, and a structure 23 composed of a polysilicon layer 22 are connected to each other through a part 22a, 22c of the polysilicon region so that a part 22b of the polysilicon region faces the detection electrode 12. And bonding the silicon wafer 21 and the polysilicon layer 22 to the glass substrate 10 by using the film 20 as an etch stop layer, and removing the film 20 to form the polysilicon bonded to the glass substrate 10. A step of obtaining a semiconductor inertial sensor 50 having a pair of fixed electrodes 27 and 28 and a movable electrode 26 made of polysilicon sandwiched between the pair of fixed electrodes 27 and 28 and floating on the glass substrate 10 so as to face the detection electrode 12. And a method for manufacturing a semiconductor inertial sensor.

In the manufacturing method according to the first to sixth aspects, since laser processing is not required and suitable for mass production, a semiconductor inertial sensor can be manufactured at low cost. Further, since a glass substrate is used as the substrate, the sensor has low parasitic capacitance. When the structure 23 is bonded to the glass substrate 10, anodic bonding is adopted. However, since the opening 20 a is formed in the film 20, a pulse current generated during anodic bonding is generated by the opening 20 a. Flows easily between the structure 23 and the glass substrate 10 through the glass substrate 10. As a result, stronger anodic bonding can be performed.

In this specification, "a film that can be etched without eroding silicon" means that an etchant that does not corrode silicon when etching the film can be selected. . When this film is used as an etch stop layer, it is possible to etch only silicon with an etchant different from the above etchant. Examples of the film having such properties include an oxide film and a nitride film.

[0014]

Embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1 and 2, a semiconductor inertial sensor 30 according to a first embodiment of the present invention is an acceleration sensor, and includes a fixed electrode 2 fixed on a glass substrate 10.
A movable electrode 26 is provided between 7 and 28. Movable electrode 2
6. The fixed electrodes 27 and 28 are each made of polysilicon, and the opposing portions of the electrodes 26 and 27 and the electrodes 26 and 28 are formed in a comb shape. Movable electrode 26
Is positioned above the glass substrate 10, both ends of which are supported by the beams 31, and floats with respect to the glass substrate 10. The base 31 a of the beam 31 is fixed on the substrate 10. Although not shown, electric wires are individually provided to the beam base 31a and the fixed electrodes 27 and 28. In the semiconductor inertial sensor 30, the movable electrode 26
When an acceleration in a horizontal direction orthogonal to a line connecting the beam base ends 31a and 31a acts as shown by arrows in the figure, the movable electrode 26 vibrates around the beams 31 and 31 as supporting axes. When the distance between the movable electrode 26 and the fixed electrodes 27 and 28 increases or decreases, the capacitance between the movable electrode 26 and the fixed electrodes 27 and 28 changes. The acceleration that acts is obtained from the change in the capacitance.

Next, a method of manufacturing the semiconductor inertial sensor 30 according to the first embodiment of the present invention will be described. As shown in FIG. 1, first, a concave portion 11 is formed in a glass substrate 10 by etching with an etchant such as hydrofluoric acid. On the other hand, a film 20 that can be etched without eroding silicon is formed on both surfaces of the silicon wafer 21. The film 20 may be an oxide film formed by thermally oxidizing a wafer, or SiH ₂ Cl ₂ or SiH ₄ and N by chemical vapor deposition (CVD).
For example, a silicon nitride film formed using H ₃ gas may be used. After the oxide film 20 is formed on both surfaces of the wafer, one of the films 20 is removed to expose one surface of the silicon wafer 21 and the remaining film 20 is selectively removed by patterning to form an opening 20a. These openings 20a are formed in portions where fixed electrodes 27 and 28 and a beam base end 31a to be described later are to be formed.

Although not shown, an oxide film may be formed on only one surface of the wafer and then this oxide film may be selectively removed by patterning to form an opening, or an oxide film may be formed on both surfaces of the wafer. After removing one of the membranes,
Subsequently, the remaining film may be selectively removed by patterning to form an opening. The method for forming these openings is the same for the semiconductor inertial sensor 40 according to the second embodiment and the semiconductor inertial sensor 50 according to the third embodiment described later.

A polysilicon layer 22 is formed on the exposed surface of the silicon wafer 21 and the film 20 including the opening 20a by the CVD method. An Al film 24 is formed on the surface of the polysilicon layer 22 on the film 20 by sputtering or the like, and after patterning, anisotropic dry etching at a low temperature using SF ₆ gas is performed. As a result, the polysilicon layer 22 is selectively etched away using the film 20 as an etch stop layer, and a polysilicon region 22b corresponding to a movable electrode 26 described later is formed on the film 20, and on both sides of the polysilicon region 22b. Polysilicon regions 22a and 22c corresponding to fixed electrodes 27 and 28 to be described later are formed on film 20 including opening 20a with a slight gap. After removing the Al film 24, the polysilicon region 2 is removed.
2a, 22b, 22c, film 20, silicon wafer 21
Then, the structure 23 made of the polysilicon layer 22 is anodically bonded to the glass substrate 10 via the polysilicon regions 22a and 22c so that the polysilicon region 22b faces the concave portion 11. Thereafter, the silicon wafer 21 and the polysilicon layer 22 thereon constituting the structure 23 are removed by performing wet etching with an etchant such as KOH or dry etching with an etchant such as SF ₆ using the film 20 as an etch stop layer. . If over-etching occurs during this etching process, grooves corresponding to the openings 20a are formed in the polysilicon regions 22a and 22c. Subsequently, wet etching with an etchant such as hydrofluoric acid or CF
Dry etching is performed with an etchant such as ₄ to remove the film 20 by etching. As a result, a semiconductor inertial sensor 30 is obtained in which the movable electrode 26 made of polysilicon is sandwiched between the pair of fixed electrodes 27 and 28 made of polysilicon and floats above the recess 11.

FIGS. 3 and 4 show a semiconductor inertial sensor 40 according to a second embodiment. The semiconductor inertial sensor 40 is an acceleration sensor, and includes a movable electrode 26 between a frame 29 fixed on a glass substrate 10 having a detection electrode 12 formed on the surface.
Having. The movable electrode 26 and the frame body 29 are each made of polysilicon, and the electrodes 26 are housed in the window frame-shaped frame body 29 at intervals. The movable electrode 26 is located above the detection electrode 12, both ends of which are supported by beams 31, and floats with respect to the glass substrate 10. The base end 31 a of the beam 31 is located in the recess 29 a of the frame 29 and is fixed on the substrate 10. Although not shown, the beam base end 3
Electrical wiring is individually made to the 1a and the detection electrode 12.
In this semiconductor inertial sensor 40, beam base ends 31a and 31a are
When a vertical acceleration perpendicular to the line connecting is applied, the movable electrode 26 vibrates around the beams 31 and 31 as a supporting axis.
The distance between the movable electrode 26 and the detection electrode 12 increases,
When the width is reduced, the capacitance between the movable electrode 26 and the detection electrode 12 changes. The acceleration that acts is obtained from the change in the capacitance.

Next, a method of manufacturing the semiconductor inertial sensor 40 according to the second embodiment of the present invention will be described. As shown in FIG. 4, first, a concave portion 11 is formed on a glass substrate 10 by etching with an etchant such as hydrofluoric acid, and Au, Pt, C is formed on the bottom surface of the concave portion 11 by sputtering, vacuum deposition, or the like.
The detection electrode 12 made of a thin film of a metal selected from u or the like is formed. On the other hand, the oxide film 20 is formed on both surfaces of the silicon wafer 21 in the same manner as in the manufacturing method of the first embodiment. The opening 20a is formed by removing one of the films 20 to expose one surface of the silicon wafer 21 and selectively removing the remaining film 20 by patterning. These openings 20a are provided with a frame 29 and a beam base end 3 which will be described later.
1a is formed at a portion to be formed. Silicon wafer 2
1 on the film 20 including the exposed surface and the opening 20a.
The polysilicon layers 22 are respectively formed by the VD method.
An Al film 24 is formed on the surface of the polysilicon layer 22 on the film 20 by sputtering or the like, and is patterned.
Perform anisotropic dry etching at a low temperature using F ₆ gas. As a result, the polysilicon layer 22 is selectively etched away using the film 20 as an etch stop layer, and a polysilicon region 22b corresponding to a movable electrode 26 described later is formed on the film 20, and on both sides of the polysilicon region 22b. Polysilicon regions 22a and 22c corresponding to frames 29, 29 described later are formed on film 20 including openings 20a with a slight gap. After removing the Al film 24,
The structure 23 composed of the polysilicon regions 22a, 22b, 22c, the film 20, the silicon wafer 21, and the polysilicon layer 22 is used as a part of the polysilicon region 22b to detect the detection electrode 1.
2 is anodically bonded to the glass substrate 10 through portions 22a and 22c of the polysilicon region. Thereafter, the silicon wafer 21 constituting the structure 23 and the polysilicon layer 22 thereon are etched away in the same manner as in the first embodiment, using the film 20 as an etch stop layer. If over-etching occurs during this etching process, grooves corresponding to the openings 20a are formed in the polysilicon regions 22a and 22c. Subsequently, the film 20 is etched away in the same manner as in the first embodiment. As a result, frames 29 and 29 made of polysilicon bonded to the glass substrate 10 and a movable electrode 26 made of polysilicon sandwiched between the frames 29 and 29 and floating opposite to the detection electrode 12 were formed. A semiconductor inertial sensor 40 is obtained.

FIGS. 5 and 6 show a semiconductor inertial sensor 50 according to a third embodiment. The semiconductor inertial sensor 50 is an angular velocity sensor, and includes a pair of movable electrodes 26 having a tuning fork structure between fixed electrodes 27 and 28 fixed on the glass substrate 10.
26. Movable electrode 26, fixed electrodes 27 and 28
Are made of polysilicon, and the electrodes 26 and 2
7 and the opposing portions of the electrode 26 and the electrode 28 are formed in a comb shape. The movable electrodes 26, 26 have a U-shaped beam 3.
Both ends are supported by 1 and 31 and float with respect to the glass substrate 10. The base 31 a of the beam 31 is fixed on the substrate 10. Concave portion 11 of silicon substrate 10
Is formed with a detection electrode 12. Although not shown, electric wires are individually provided to the beam base 31a, the fixed electrodes 27 and 28, and the detection electrode 12, and an alternating voltage is applied to the fixed electrodes 27 and 28 so that the movable electrode is excited by electrostatic force. Has become. In the semiconductor inertial sensor 50, when an angular velocity acts on the movable electrodes 26, 26 around a line connecting the beam base ends 31a, 31a, the movable electrodes 26, 26
26 generates a Coriolis force, causing torsional vibration around this center line and resonating. The angular velocity acting due to the change in the capacitance between the movable electrode 26 and the detection electrode 12 at the time of the resonance is detected.

Next, a method of manufacturing the semiconductor inertial sensor 50 according to the third embodiment of the present invention will be described. As shown in FIG. 5, a concave portion 11 is first formed on a glass substrate 10 by etching with an etchant such as hydrofluoric acid, and Au, Pt, and C are formed on the bottom surface of the concave portion 11 by sputtering, vacuum deposition, or the like.
The detection electrode 12 made of a thin film of a metal selected from u or the like is formed. On the other hand, the oxide film 20 is formed on both surfaces of the silicon wafer 21 in the same manner as in the manufacturing method of the first embodiment. The opening 20a is formed by removing one of the films 20 to expose one surface of the silicon wafer 21 and selectively removing the remaining film 20 by patterning. These openings 20a are formed in portions where fixed electrodes 27 and 28 and a beam base end 31a to be described later are to be formed. Film 2 including exposed surface of silicon wafer 21 and opening 20a
The polysilicon layers 22 are formed on the layers 0 by the CVD method. An Al film 24 is formed on the surface of the polysilicon layer 22 on the film 20 by sputtering or the like, and after patterning, anisotropic dry etching at a low temperature using SF ₆ gas is performed. As a result, the polysilicon layer 22 is selectively etched away using the film 20 as an etch stop layer, and a polysilicon region 22b corresponding to a movable electrode 26 to be described later is formed on the film 20.
A fixed electrode 2 to be described later is provided with a slight gap on both sides of 2b.
Polysilicon regions 22a and 22c corresponding to 7, 28
Is formed on the film 20 including the opening 20a. Al film 2
4 are removed, the polysilicon regions 22a, 22b, 2
2c, a structure 23 composed of a film 20, a silicon wafer 21 and a polysilicon layer 22 is formed as a part 2 of a polysilicon region.
2b is anodically bonded to the glass substrate 10 via portions 22a and 22c of the polysilicon region such that the electrode 2b faces the detection electrode 12. Thereafter, the silicon wafer 21 constituting the structure 23 and the polysilicon layer 22 thereon are etched away in the same manner as in the first embodiment, using the film 20 as an etch stop layer. If over-etching occurs during this etching process, the polysilicon regions 22a and 22a
A groove corresponding to the opening 20a is formed in 2c. Subsequently, the film 20 is etched away in the same manner as in the first embodiment. Thereby, the movable electrode 26 made of polysilicon is formed.
Is formed between a pair of fixed electrodes 27 and 28 made of polysilicon, and a movable electrode 26 made of polysilicon floating opposite to the detection electrode 12.
0 is obtained.

[0022]

As described above, unlike the conventional method of manufacturing a semiconductor inertial sensor by laser processing of a wafer, according to the present invention, laser processing is not required and a low-cost semiconductor inertial sensor suitable for mass production is manufactured. can do.
Since a structure including a movable electrode, a fixed electrode or a frame is bonded to a glass substrate while being supported by a silicon wafer and a polysilicon layer having a desired thickness, a sticking phenomenon as in the related art occurs. This does not occur, and the movable electrode can be provided at a predetermined gap with respect to the detection electrode and the glass substrate. In addition, a strong anodic bonding can be easily performed by having a structure that does not hinder the flow of the pulse current generated at the time of anodic bonding between the glass substrate and the wafer.

Further, by using a glass substrate instead of a silicon substrate, in a sensor that performs detection using electrostatic capacitance, the parasitic capacitance of the element is reduced, and a highly sensitive and accurate semiconductor inertial sensor can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a semiconductor inertial sensor according to a first embodiment of the present invention, corresponding to a main part of line AA in FIG. 2, and a manufacturing process thereof.

FIG. 2 is an external perspective view of the semiconductor inertial sensor according to the first embodiment of the present invention.

FIG. 3 is an external perspective view of a semiconductor inertial sensor according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a semiconductor inertial sensor according to a second embodiment of the present invention corresponding to a main part of line BB in FIG. 3 and a manufacturing process thereof.

FIG. 5 is a sectional view showing a semiconductor inertial sensor according to a third embodiment of the present invention, corresponding to a main part of line CC in FIG. 6, and a manufacturing process thereof;

FIG. 6 is an external perspective view of a semiconductor inertial sensor according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Glass substrate 11 Concave part 12 Detection electrode 20 Film 20a Opening 21 Silicon wafer 22 Polysilicon layer 22a, 22b, 22c Polysilicon area 23 Structure 26 Movable electrode 27, 28 A pair of fixed electrode 30, 40, 50 Semiconductor inertial sensor

Claims (3)

[Claims] 1. A step of forming a concave portion (11) in a glass substrate (10), and forming a film (20) that can be etched without eroding silicon having an opening (20a) on one surface of a silicon wafer (21). Forming, and the other side of the silicon wafer (21) and the opening
Forming a polysilicon layer (22) on the film (20) including (20a); and a polysilicon layer on the film (20) including the opening (20a).
Forming a plurality of polysilicon regions (22a, 22b, 22c) separated from each other by selectively removing (22) by etching, the polysilicon regions (22a, 22b, 22c), the film (20), A structure (23) comprising the silicon wafer (21) and the polysilicon layer (22) is partially (22b) of the polysilicon region.
Bonding to the glass substrate (10) via a part (22a, 22c) of the polysilicon region so as to face the concave portion (11), and the silicon wafer (21) and the polysilicon layer (22). A) etching the film (20) as an etch stop layer, and removing the film (20), thereby removing the glass substrate (10).
A pair of fixed electrodes (27, 2
8) and a step of obtaining a semiconductor inertial sensor (30) having a movable electrode (26) made of polysilicon sandwiched between the pair of fixed electrodes (27, 28) and floating above the glass substrate (10). A method for manufacturing a semiconductor inertial sensor including: 2. A step of forming a concave portion (11) in a glass substrate (10); a step of forming a detection electrode (12) on a bottom surface of the concave portion (11) of the glass substrate (10); Forming a film (20) that can be etched without eroding silicon having an opening (20a) on one surface of the silicon wafer (21), and the remaining one surface of the silicon wafer (21) and the opening
Forming a polysilicon layer (22) on the film (20) including (20a); and a polysilicon layer on the film (20) including the opening (20a).
Forming a plurality of polysilicon regions (22a, 22b, 22c) separated from each other by selectively removing (22) by etching, the polysilicon regions (22a, 22b, 22c), the film (20), A structure (23) comprising the silicon wafer (21) and the polysilicon layer (22) is partially (22b) of the polysilicon region.
Bonding to the glass substrate (10) via a part (22a, 22c) of the polysilicon region so as to face the detection electrode (12), and the silicon wafer (21) and the polysilicon layer ( 22) etching the film (20) using the film (20) as an etch stop layer, and by removing the film (20), the glass substrate (10)
Obtaining a semiconductor inertial sensor (40) having a movable electrode (26) made of polysilicon floating above the detection electrode (12). A step of forming a concave portion (11) in the glass substrate (10); a step of forming a detection electrode (12) on the bottom surface of the concave portion (11) of the glass substrate (10); Forming a film (20) that can be etched without eroding silicon having an opening (20a) on one surface of the silicon wafer (21), and the remaining one surface of the silicon wafer (21) and the opening
Forming a polysilicon layer (22) on the film (20) including (20a); and a polysilicon layer on the film (20) including the opening (20a).
Forming a plurality of polysilicon regions (22a, 22b, 22c) separated from each other by selectively removing (22) by etching, the polysilicon regions (22a, 22b, 22c), the film (20), A structure (23) comprising the silicon wafer (21) and the polysilicon layer (22) is partially (22b) of the polysilicon region.
Bonding to the glass substrate (10) via a part (22a, 22c) of the polysilicon region so as to face the detection electrode (12), and the silicon wafer (21) and the polysilicon layer ( 22) etching the film (20) using the film (20) as an etch stop layer, and by removing the film (20), the glass substrate (10)
A pair of fixed electrodes (27, 2
8) and a movable electrode (26) made of polysilicon sandwiched between the pair of fixed electrodes (27, 28) and floating on the glass substrate (10) in opposition to the detection electrode (12). Obtaining a sensor (50).