WO2012102292A1

WO2012102292A1 - Method for producing electrostatic capacitance device

Info

Publication number: WO2012102292A1
Application number: PCT/JP2012/051507
Authority: WO
Inventors: 巧田浦; 友洋中谷; 真奥村; 江田　和夫; 後藤　浩嗣; 秀一屋地
Original assignee: パナソニック株式会社
Priority date: 2011-01-27
Filing date: 2012-01-25
Publication date: 2012-08-02
Also published as: JP2012156401A; TW201234013A

Abstract

Penetrating silicon (23a, 23b, 24a, 24b) formed by causing silicon to penetrate in a manner so as to be exposed at both surfaces of an affixed-side substrate (2a) are considered affixed electrodes (20a, 20b, 21a, 21b), a metal film (25) is formed on the outside exposed surface of the penetrating silicon (23a, 23b, 24a, 24b), and a metal film (26) is formed in a manner so as to be separated from metal film (25) at a position other than the outside exposed surface of the penetrating silicon (23a, 23b, 24a, 24b) at the surface of the affixed-side substrate (2a). Also, during positive electrode connection of a mobile body substrate (1) and the affixed-side substrate (2a), using the metal films (25, 26), an electrical potential difference is provided between the affixed-side substrate (2a) and the mobile body substrate (1), while the penetrating silicon (23a, 23b, 24a, 24b) and the mobile body substrate (1) form in the same electrical potential.

Description

Capacitive device manufacturing method

The present invention relates to a method for manufacturing a capacitance type device.

Conventionally, as a capacitive device, the center of the movable electrode is supported by a beam, and the center of gravity on both ends of the movable electrode is asymmetrical with the center supported by the beam as the boundary, so that acceleration is input. There is known one in which a movable electrode is swung when it is applied (see, for example, Patent Document 1).

In Patent Document 1, a movable electrode is formed on a silicon substrate that is a movable substrate, while a fixed electrode that is opposed to the movable electrode is formed on a glass substrate that is a stationary substrate, and both substrates are joined by anodic bonding. .

By the way, when bonding both substrates by anodic bonding, the pressure contact electrode provided on the silicon substrate and the terminal electrode extending from the fixed electrode formed on the glass substrate are crushed and made conductive, thereby fixing the silicon substrate. In general, the electrode is at the same potential.

JP 2010-210419 A

However, as in the above prior art, in the method in which the silicon substrate and the fixed electrode are made to have the same potential by stepping on the electrodes, an oxide film or the like is formed on the joint surface where the stepping is performed, resulting in poor conduction. Could occur. Further, when such a crushing structure is used, there is a possibility that the crushing portion serves as a starting point of stress and stress acts on the structure to affect the device characteristics.

Therefore, an object of the present invention is to obtain a manufacturing method of a capacitance type device that can suppress the influence on the device characteristics.

A first feature of the present invention is an electrostatic comprising: a movable body substrate on which a movable electrode is formed; and a fixed side substrate on which a fixed electrode facing the movable electrode is formed and is anodically bonded to the movable body substrate. A method of manufacturing a capacitive device, wherein a through silicon formed by penetrating silicon so as to be exposed on both surfaces of the fixed side substrate is used as the fixed electrode, and at least the fixed side substrate of the movable substrate is an anode. A portion to be joined is formed of silicon, a first metal film is formed on the outer exposed surface of the through silicon, and the first metal film is formed on the surface of the fixed side substrate at a portion other than the outer exposed surface of the through silicon. A second metal film is formed so as to be separated from the first metal film, and the first metal film and the second metal film are used when anodic bonding the movable substrate and the stationary substrate. The fixed While a potential difference between the substrate and the movable member substrate, and summarized in that said movable body substrate and the through-silicon was set to be the same potential.

The gist of the second feature of the present invention is that the shortest distance between the second metal film and the through silicon is made larger than the thickness of the fixed substrate.

The third feature of the present invention is summarized in that the material of the first metal film and the second metal film is aluminum.

A fourth feature of the present invention is that the anodic bonding of the movable substrate and the fixed substrate is performed at a wafer level, and the film is formed on the outer exposed surface of the penetrating silicon serving as the fixed electrode over the entire wafer surface. The gist is that the metal films 1 are electrically connected to each other by metal wiring.

According to the present invention, a potential difference is provided between the fixed substrate and the movable substrate, and anodic bonding between the movable substrate and the fixed substrate is performed with the through silicon and the movable substrate at the same potential. ing. Therefore, anodic bonding can be performed without using a stepping-down structure. As a result, it is possible to suppress the formation of an oxide film at the bonding portion, resulting in poor conduction, and to suppress the stress from acting on the squashed portion and affecting the device characteristics. it can.

In addition, a metal film is used to provide a potential difference between the fixed-side substrate and the movable substrate, while the through silicon and the movable substrate are set to the same potential. Can be done.

It is a disassembled perspective view which shows the electrostatic capacitance type device concerning one Embodiment of this invention. The movable body board | substrate of the electrostatic capacitance type device shown in FIG. 1 is shown, (a) is a top view of a movable body board | substrate, (b) is a bottom view of a movable body board | substrate. It is typical sectional drawing of the electrostatic capacitance type device shown in FIG. It is a top view of the wafer which shows the middle of manufacture of the electrostatic capacitance type device shown in FIG. It is an enlarged view of the I section in FIG. It is an enlarged view of the II section in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Below, an acceleration sensor is illustrated as an electrostatic capacitance type device. Further, the side of the weight portion on which the movable electrode is formed is defined as the surface side of the silicon substrate. In the following description, the short direction of the silicon substrate is the X direction, the long direction of the silicon substrate is the Y direction and the thickness direction of the silicon substrate is the Z direction.

The acceleration sensor S according to this embodiment includes a silicon substrate 1 as a movable substrate having

movable electrodes

4 and 5, and anodically bonded to the surface of the silicon substrate 1 (upper surface in FIG. 1). An upper fixing plate 2a as a fixed-side substrate on which opposed

fixed electrodes

20a, 20b, 21a and 21b are formed, and a lower fixing plate 2b which is bonded to the back surface (the lower surface in FIG. 1) of the silicon substrate 1 and serves as a closing plate It has. Thus, the acceleration sensor S according to the present embodiment is configured as a sensor chip in which the silicon substrate 1 is sandwiched between the upper fixed plate 2a and the lower fixed plate 2b.

The silicon substrate 1 is formed of a silicon SOI substrate. As shown in FIG. 1, the frame 3 having two

rectangular frames

3a and 3b and a side wall of the

rectangular frames

2a and 3b are spaced from each other. Two

movable electrodes

4 and 5 having a rectangular shape arranged in the

rectangular frames

3a and 3b are provided.

The

movable electrodes

4 and 5 are connected to the side walls of the

rectangular frames

3a and 3b by the pair of

beams

6a and 6b and 7a and 7b at substantially the center of the two opposite sides of each side surface. That is, one movable electrode 4 is swingably supported with respect to the frame 3 by the

beams

6a and 6b, and the other movable electrode 5 is swingably supported with respect to the frame 3 by the

beams

7a and 7b. Yes. In this embodiment, the

beams

6a and 6b and the

beams

7a and 7b are biased to the surface side (upper surface side in FIG. 1) facing the upper fixing plate 2a with respect to the Z direction (thickness direction) of the silicon substrate 1. Are arranged. Further, on the front and back surfaces of the

movable electrodes

4 and 5, the protrusions 41 for preventing the

movable electrodes

4 and 5 from directly colliding with the

fixed electrodes

20a, 20b, 21a and 21b and the

adhesion preventing films

28 and 29 described later. , 51 are projected. A ground electrode 10 is formed on the surface of the frame 3 of the silicon substrate 1.

The

movable electrodes

4 and 5 are formed thick and have a function as weights. In this embodiment, as shown in FIGS. 2B and 3, one side of a boundary line M (a straight line connecting the centers of the beam 6 a and the beam 6 b in a plan view) M on the back side of the movable electrode 4 (FIG. 2B ) (Lower side) is formed with a recess 11 so that the center of gravity of the movable electrode 4 is shifted to the other side (upper side in FIG. 2B). Similarly, the concave portion 11 is formed on the other side (the upper side of FIG. 2B) opposite to the one side where the concave portion 11 is provided on the movable electrode 4 on the back side of the movable electrode 5. Is shifted to one side (the lower side in FIG. 2B). When acceleration is applied in the X direction or the Z direction, the acceleration applied in the X direction and the Z direction can be detected.

The upper fixed plate 2a is formed of a glass substrate, and is disposed to face the surfaces of the

movable electrodes

4 and 5 with a predetermined interval as shown in FIG. Then,

fixed electrodes

20a and 20b are provided on one side and the other side of the boundary line M on the side of the upper fixed plate 2a facing the one movable electrode 4, respectively. The

fixed electrodes

20a and 20b are arranged to face the surface 4a of one movable electrode 4 with a predetermined interval.

Further, fixed

electrodes

21a and 21b are respectively provided on one side and the other side of the boundary line M on the surface side facing the other movable electrode 5 of the upper fixed plate 2a. It is arranged opposite to the surface of the other movable electrode 5 at a predetermined interval.

Further, as shown in FIG. 1, a through hole 22a is formed at a position facing the ground electrode 10 of the upper fixing plate 2a, and the ground electrode 10 is exposed and wired through the through hole 22a. Thus, the potential of the ground electrode 10, that is, the potential of the

movable electrodes

4 and 5 can be taken out to the outside.

The lower fixed plate 2b is formed of a glass substrate, and is disposed so as to face the back surfaces of both

movable electrodes

4 and 5 with a predetermined interval as shown in FIG. Then, on the surface of the lower fixed plate 2b,

adhesion preventing films

28 and 29 are formed in areas corresponding to the installation areas of the

movable electrodes

4 and 5, respectively (see FIG. 1).

The acceleration sensor S described above is manufactured as follows.

First, as shown in FIG. 3, recesses 32a and 32b for moving the

movable electrodes

4 and 5 are formed on the front side and the back side of the silicon substrate 1 by wet etching, dry etching, or the like. Moreover, both the

movable electrodes

4 and 5 and the recessed part 11 are formed by further etching the back surface side of the silicon substrate 1.

Thereafter, the lower fixing plate 2b is anodically bonded to the back side of the silicon substrate 1, and fixed

electrodes

20a, 20b, 21a, 21b and through holes 22a are formed on the upper fixing plate 2a. Anodically bonded to the surface side of the silicon substrate 1.

In the acceleration sensor S configured as described above, when the acceleration indicated by the arrow k in FIG. 3 is applied, both the

movable electrodes

4 and 5 swing, so that both end sides of the

movable electrodes

4 and 5 and the fixed electrode are moved. The gap d between 20a, 20b, 21a and 21b changes, and the capacitances C1, C2, C3 and C4 between these gaps d change.

The capacitance C at this time is known to be C = ε × S / d (ε: dielectric constant, S: electrode area, d: gap), and the electrostatic capacity increases as the gap d increases from this equation. The capacitance C decreases, and the capacitance C increases as the gap d decreases.

In the present embodiment, the detected capacitances C1, C2, C3, and C4 are sent to an arithmetic circuit constituted by, for example, an ASIC, and the acceleration in the X direction and the acceleration in the Z direction are obtained to indicate the acceleration. Data is output.

By the way, in this embodiment, while arrange | positioning 1st acceleration sensor single-piece | unit Sa provided with one movable electrode 4 and 2nd acceleration sensor single-piece | unit Sb provided with the other movable electrode 5, in the same chip surface, Each acceleration sensor unit Sa, Sb is arranged in a state of being relatively rotated 180 degrees (see FIG. 1). In this way, the first acceleration sensor unit Sa and the second acceleration sensor unit Sb are arranged such that the center of gravity positions of the movable electrode 4 and the movable electrode 5 are opposite to the boundary line M. By doing so, the acceleration in the X direction and the Z direction can be detected. The calculation processing for obtaining the direction and magnitude of the acceleration in the X direction and the Z direction is well known in the art and will not be described.

Here, in this embodiment, a potential difference is provided between the upper fixed plate (fixed side substrate) 2a and the silicon substrate (movable body substrate) 1, and the through

silicones

23a, 23b, 24a, 24b and the silicon substrate (movable body) are provided. With the substrate 1 being at the same potential, anodic bonding between the silicon substrate (movable substrate) 1 and the upper fixed plate (fixed side substrate) 2a is performed.

Specifically, anodic bonding between the silicon substrate 1 and the upper fixing plate 2a is performed as follows.

First, as shown in FIG. 1 and FIG. 3, the portion corresponding to the

movable electrodes

4, 5 in a plan view of the upper fixed plate 2 a, that is, the portion where the above-described

fixed electrodes

20 a, 20 b, 21 a, 21 b are arranged, A plurality of through

silicones

23a, 23b, 24a, 24b are formed by penetrating silicon so as to be exposed on both the front and back surfaces of the upper fixing plate 2a. Then, the back surfaces of the through

silicones

23a, 23b, 24a and 24b are fixed

electrodes

20a, 20b, 21a and 21b.

Such a glass-embedded silicon substrate is formed by, for example, forming a depression on the surface of a flat silicon substrate, superimposing the surface on which the depression of the silicon substrate is formed on the flat glass substrate, and heating the glass substrate to After a part of the substrate is embedded in the recess, the glass substrate can be re-solidified, and the front and back surfaces of the flat substrate can be polished to remove silicon.

Then, at least a portion of the silicon substrate 1 to be anodically bonded to the upper fixing plate 2a is formed of silicon.

In the present embodiment, both-surface peripheral portions of the silicon substrate 1 are anodically bonded to the peripheral portions of the upper fixing plate 2a and the lower fixing plate 2b, respectively. In this embodiment, an SOI substrate in which a buried insulating layer 1a made of SiO2 is interposed between a silicon active layer 1b made of Si and a support substrate 1c made of Si is used as the silicon substrate 1.

As described above, by using the SOI substrate as the silicon substrate 1, at least the portion to be anodically bonded to the upper fixing plate 2a of the silicon substrate 1 is formed of silicon.

Then, an aluminum film 25 as a first metal film is formed on the outer exposed surfaces of the penetrating

silicons

23a, 23b, 24a, 24b, and the outer peripheral edge of the upper fixing plate 2a (the penetration on the surface of the upper fixing plate 2a). An aluminum film 26 as a second metal film is formed on the

silicon

23 a, 23 b, 24 a, 24 b other than the outer exposed surface so as to be separated from the aluminum film 25. In this way, the aluminum film 25 and the aluminum film 26 are formed so as not to contact each other, thereby preventing the aluminum film 25 and the aluminum film 26 from being short-circuited.

The through

silicones

23a, 23b, 24a, and 24b are grounded through the aluminum film 25 and the metal wiring w2, and the peripheral portion of the silicon substrate 1 is grounded through the metal wiring w3. 24a, 24b and the silicon substrate 1 are set to the same potential.

Then, a voltage is applied to the joint portion (peripheral portion) of the upper fixed plate 2a with the silicon substrate 1 via the aluminum film 26 and the metal wiring w1, and the upper fixed plate (fixed side substrate) 2a and the silicon substrate (movable body). By providing a potential difference between the silicon substrate (movable substrate) 1 and the upper portion of the silicon substrate (movable substrate) 1 and the silicon substrate (movable substrate) 1 at the same potential. Anodic bonding with the fixed plate (fixed side substrate) 2a is performed.

That is, in this embodiment, when the silicon substrate (movable substrate) 1 and the upper fixed plate (fixed side substrate) 2a are anodically bonded, the aluminum films (first and second metal films) 25 and 26 are used. In addition, a potential difference is provided between the upper fixed plate (fixed side substrate) 2a and the silicon substrate (movable substrate) 1, and the through

silicones

23a, 23b, 24a, 24b and the silicon substrate (movable substrate) 1 are the same. The electric potential is set.

At this time, as shown in FIG. 3, the aluminum film (spaced apart from the aluminum film 25 as the first metal film in a portion other than the outer exposed surface of the through

silicon vias

23a, 23b, 24a, 24b on the surface of the upper fixing plate 2a). It is preferable that the shortest distance a between the second metal film 26 formed in this way and the penetrating

silicons

23a, 23b, 24a, 24b is larger than the thickness b of the upper fixing plate 2a (a> b). is there.

Since an interface between glass and silicon is generated at the junction between the upper fixing plate 2a and the silicon substrate 1 and the through portions of the through

silicones

23a, 23b, 24a, and 24b, when a <b, the upper fixing plate When a voltage is applied to the aluminum film 26 of 2a, a bonding reaction is likely to occur at the through portions of the through

silicones

23a, 23b, 24a, and 24b that are close to each other. However, if a> b, it is possible to suppress a bonding reaction from occurring in the through portions of the through

silicones

23a, 23b, 24a, and 24b, and to actively join the upper fixing plate 2a and the silicon substrate 1. It becomes possible to cause a bonding reaction at the part.

Further, in this embodiment, a plurality of through silicons (four in this embodiment) serving as fixed electrodes are provided, and an aluminum film (a plurality of through silicons formed on each through

silicon

23a, 23b, 24a, 24b) is provided. The first metal film 25 formed on the outer exposed surface is electrically connected to each other by metal wiring (metal wiring 27 and metal wiring w2) (see FIG. 6).

As described above, in the present embodiment, a plurality of aluminum films 25 are electrically connected to each other by the metal wiring (metal wiring 27 and metal wiring w2), so that the silicon substrate (movable body substrate) is obtained at the wafer level as shown in FIG. ) 1 and the upper fixing plate (fixed side substrate) 2a are anodic bonded.

Hereinafter, anodic bonding at the wafer level will be described.

First, by processing one wafer W by etching or the like, a plurality of

movable electrodes

4 and 5 are formed so that the above-described acceleration sensor S is formed when the wafer W is divided.

Next, the glass substrate (the member that becomes the upper fixing plate 2a when divided) is embedded in the through

silicones

23a, 23b, 24a, in which the through

silicons

23a, 23b, 24a, 24b to be the fixed

electrodes

20a, 20b, 21a, 21b are embedded. 24b face the

movable electrodes

4 and 5.

Next, an aluminum film (first metal film formed on the outer exposed surface of the plurality of through silicon) 25 is formed on the surface of the glass substrate. At this time, a metal wiring 27 is provided between the aluminum films 25 of the adjacent through

silicones

23a and 23b and between the aluminum films 25 of the adjacent through

silicones

24a and 24b. . Further, the plurality of aluminum films 25 are electrically connected to each other by the metal wiring (metal wiring 27 and metal wiring w2), and are electrically connected to the ground electrode Wa disposed on a part of the outer periphery of the wafer W via the metal wiring w2. Yes. That is, the aluminum films (first metal films) 25 formed on the outer exposed surfaces of the through

silicon vias

23a, 23b, 24a, and 24b that become the

fixed electrodes

20a, 20b, 21a, and 21b over the entire surface of the wafer W are metal wirings. They are electrically connected to each other by (metal wiring 27 and metal wiring w2).

Further, an aluminum film is formed on the surface of the glass substrate so as to be separated from the aluminum film 25 as the first metal film in a portion other than the outer exposed surface of the through

silicones

23a, 23b, 24a, 24b on the surface of the upper fixing plate 2a. 26) (corresponding to the second metal film formed). The aluminum film 26 is formed on a portion that becomes the peripheral edge of the acceleration sensor S when it is divided on the surface of the glass substrate. The aluminum film 26 is electrically connected to the voltage application electrode Wb disposed so as to surround the outer periphery of the wafer W through the metal wiring w1.

The aluminum film 25, the aluminum film 26, the metal wiring 27, the metal wiring w1, and the metal wiring w2 may be formed at the same time, or any one of them may be formed first.

Further, as described above, the silicon substrate 1 is grounded through the metal wiring w3.

In this state, a voltage is applied to the joint portion (peripheral portion) of the upper fixed plate 2a with the silicon substrate 1 via the voltage application electrode Wb, and the upper fixed plate (fixed side substrate) 2a and the silicon substrate (movable substrate). ) By providing a potential difference with respect to 1, anodic bonding can be performed in a lump with the through

silicones

23 a, 23 b, 24 a, 24 b and the silicon substrate (movable substrate) 1 at the same potential.

That is, anodic bonding of the silicon substrate (movable body substrate) 1 and the upper fixed plate (fixed side substrate) 2a is achieved by connecting a plurality of aluminum films 25 to each other through metal wiring (metal wiring 27 and metal wiring w2). It can be done at the wafer level.

In the present embodiment, the voltage value applied to the aluminum film 26 from the voltage application electrode Wb is exemplified as -600 V. However, the voltage value can be appropriately set according to the conditions for anodic bonding. It is.

Since the lower fixed plate 2b is a portion where no fixed electrode or movable electrode is provided, anodic bonding between the silicon substrate 1 and the lower fixed plate 2b can be performed by a conventional method. Anodic bonding may be performed by the same method.

Then, of the

aluminum films

25 and 26, the metal wirings w1, w2, and w3 and the metal wiring 27, the portions left on the surface are patterned to remove the other portions.

Originally, the

aluminum films

25, 26, the metal wirings w 1, w 2, w 3 and the metal wiring 27 are removed after anodic bonding. However, in this embodiment, the aluminum film 25 is left and the wire that will be implemented later is used. It is used as a bonding pad.

Then, after anodic bonding at the wafer level, a plurality of acceleration sensors S are manufactured by dividing into individual chips.

In addition, by using the remaining aluminum film 25 as a wire bonding pad, the potentials of the fixed

electrodes

20a and 20b and the fixed

electrodes

21a and 21b can be extracted to the outside.

As described above, in this embodiment, a potential difference is provided between the upper fixed plate (fixed side substrate) 2a and the silicon substrate (movable body substrate) 1, and the through

silicones

23a, 23b, 24a, 24b and the silicon substrate are provided. The anodic bonding of the silicon substrate (movable substrate) 1 and the upper fixed plate (fixed side substrate) 2a is performed with the (movable substrate) 1 at the same potential. Therefore, anodic bonding can be performed without using a stepping-down structure. As a result, it is possible to suppress the formation of an oxide film at the bonding portion, resulting in poor conduction, and to suppress the stress from acting on the squashed portion and affecting the device characteristics. it can.

As described above, according to the present embodiment, it is possible to obtain an acceleration sensor (capacitive device) S capable of suppressing the influence on the device characteristics.

In addition, a potential difference is provided between the upper fixed plate (fixed side substrate) 2a and the silicon substrate (movable substrate) 1 using the aluminum films (first and second metal films) 25 and 26, while penetrating silicon. Since 23a, 23b, 24a, 24b and the silicon substrate (movable body substrate) 1 are set to the same potential, it is possible to more reliably apply the voltage and make the same potential. In addition, film formation and patterning can be easily performed by a method suitable for a MEMS device such as sputtering or vapor deposition.

At this time, if aluminum is used as the material of the first and second metal films, the cost can be reduced because the material is inexpensive. Such patterning by the

aluminum films

25 and 26 has an advantage that it is easy to process because both wet etching and dry etching techniques have been established. In particular, it is more effective to use aluminum when forming a minute MEMS device pattern of about several μm.

Further, according to the present embodiment, the aluminum film 26, that is, the aluminum film 25 as the first metal film on the surface of the upper fixing plate 2a other than the outer exposed surface of the through

silicones

23a, 23b, 24a, 24b, The shortest distance a between the second metal film formed so as to be separated from the penetrating

silicons

23a, 23b, 24a, and 24b is set larger than the thickness b of the upper fixing plate 2a.

Therefore, when a voltage is applied to the aluminum film 26 of the upper fixing plate 2a, it is possible to suppress the occurrence of a bonding reaction in the through portions of the through

silicones

23a, 23b, 24a, and 24b. It becomes possible to cause a bonding reaction at the bonding portion with the silicon substrate 1. That is, it is possible to cause a bonding reaction more reliably at a portion where the silicon substrate 1 and the upper fixing plate 2a are to be bonded.

Further, according to the present embodiment, the anodic bonding of the silicon substrate (movable substrate) 1 and the upper fixed plate (fixed side substrate) 2a is performed at the wafer level, and the fixed electrode 20a, The aluminum films (first metal films) 25 formed on the outer exposed surfaces of the penetrating

silicons

23a, 23b, 24a, 24b to be 20b, 21a, 21b are mutually connected by metal wiring (metal wiring 27 and metal wiring w2). Conducted. In this way, by performing anodic bonding of a plurality of acceleration sensors S collectively on the wafer, it is possible to further improve the productivity of the acceleration sensor S that can suppress the influence on the device characteristics. Can do.

In addition, the acceleration sensor S according to the present embodiment has an aluminum film (when the silicon substrate 1 and the upper fixing plate 2a are anodically bonded, the through

silicones

23a, 23b, 24a, 24b and the silicon substrate 1 are set to the same potential. For this purpose, a metal film 25 is formed on the outer exposed surface of the through

silicon vias

23a, 23b, 24a, 24b. That is, the aluminum film 25 formed for the same potential of the through

silicones

23a, 23b, 24a, 24b and the silicon substrate (movable substrate) 1 can be used as a wire bonding pad.

As a result, there is no need to form a metal film or the like again for wire bonding, the patterning or etching process can be omitted, and the process can be simplified.

If aluminum is used as the material of the metal film, film formation and patterning can be easily performed by a method suitable for a MEMS device such as sputtering or vapor deposition, and cost reduction can be achieved because the material is inexpensive. it can.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various modifications can be made.

For example, in the above-described embodiment, an acceleration sensor that detects acceleration in two directions of the X direction and the Z direction has been exemplified. However, one of the weight portions is arranged by being rotated 90 degrees in the XY plane, and the Y direction is added. An acceleration sensor that detects acceleration in three directions may be used.

In the above embodiment, the acceleration sensor is exemplified as the capacitive device. However, the present invention is not limited to this and can be applied to other capacitive devices.

In the above embodiment, the ground electrode is exposed to the outside through the through hole and wired so that the potential of the ground electrode (potential of the movable electrode) can be taken out to the outside. Through silicon may be formed, and the potential of the ground electrode (potential of the movable electrode) may be taken out from the through silicon. This facilitates the manufacture of the glass-embedded silicon substrate.

Also, movable electrodes, fixed electrodes, and other detailed specifications (shape, size, layout, etc.) can be changed as appropriate.

According to the present invention, it is possible to obtain a method for manufacturing a capacitance device that can suppress the influence on device characteristics.

Claims

A method of manufacturing a capacitive device, comprising: a movable substrate on which a movable electrode is formed; and a fixed substrate on which a fixed electrode facing the movable electrode is formed and is anodically bonded to the movable substrate. ,
A through silicon formed by penetrating silicon so as to be exposed on both surfaces of the fixed side substrate is used as the fixed electrode, and at least a portion of the movable substrate that is anodically bonded to the fixed side substrate is formed of silicon,
A first metal film is formed on the outer exposed surface of the through silicon, and the first metal film is spaced apart from the first metal film at a portion other than the outer exposed surface of the through silicon on the surface of the fixed substrate. 2 metal films are formed,
When anodically bonding the movable substrate and the fixed substrate, a potential difference is provided between the fixed substrate and the movable substrate using the first metal film and the second metal film. A method of manufacturing a capacitance type device, wherein the through silicon and the movable substrate have the same potential.
2. The method of manufacturing a capacitive device according to claim 1, wherein the shortest distance between the second metal film and the penetrating silicon is larger than the thickness of the fixed substrate.
3. The method of manufacturing a capacitive device according to claim 1, wherein the material of the first metal film and the second metal film is aluminum.
The anodic bonding of the movable substrate and the fixed substrate is performed at a wafer level,
The first metal film formed on the outer exposed surface of the through silicon serving as the fixed electrode over the entire surface of the wafer is electrically connected to each other by a metal wiring. 2. A method for manufacturing a capacitance type device according to item 1.