JP2007192587A - Wiring board for dynamic quantity sensor, manufacturing method of the wiring board for dynamic quantity sensor, and dynamic quantity sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniaturizable dynamic quantity sensor having a simple structure. <P>SOLUTION: A taper-shaped through hole is formed by using a sandblasting technique on a portion where a via hole of a planar upper glass substrate is formed. Then, an electrode pad, a wiring pattern, and a conductive pattern for extracting the electric potential to the inner wall surface of the through hole are formed. Successively, a filling member, having conductivity such as solder or Ag-based brazing material, is filled by heating inside the through hole where the conductive pattern is formed. Then, the upper glass substrate is polished to such a level that the filling member is exposed. An electrode is formed on the polished surface. After performing an anode junction between the upper glass substrate and a movable part structure, a conductive pattern for taking out an electric potential of the movable part structure is formed. A wiring pattern can be suppressed to a minimum, by forming the electrode directly under the via hole in this way, to thereby miniaturize the sensor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mechanical quantity sensor that detects, for example, a mechanical quantity such as acceleration and angular velocity, a wiring board for a mechanical quantity sensor that constitutes the mechanical quantity sensor, and a method for manufacturing a wiring board for a mechanical quantity sensor.

In a wide range of fields such as a camera shake correction device for a video camera, an in-vehicle airbag device, and a posture control device for a robot, a mechanical amount sensor for detecting a mechanical amount acting on an object is used.
One of these mechanical quantity sensors is, for example, a semiconductor sensor formed by processing a semiconductor substrate.
In this semiconductor sensor, a silicon substrate is etched to form a weight portion, which is a mass body, in the central portion. The weight portion is structured to be elastically supported by the frame (fixed portion) by a flexible beam portion.

And when a semiconductor sensor receives external forces, such as acceleration and angular velocity, a stress will act on the weight part which is a movable body. Then, the weight portion is tilted by the action of stress, and its posture changes.
By analyzing the change in the posture of the weight part, the direction and magnitude of the acting external force can be detected.
Such a mechanical quantity sensor requires a plurality of wirings for leading out signals detected inside (inside) the sensor to the outside (outside) of the sensor. These wirings are connected to the inside of the sensor. It is disposed through a through hole penetrating the outside.

In addition, in such a sensor that detects the mechanical quantity based on the posture change of the weight part, in order to reduce the air resistance when the weight part operates and to increase the detection sensitivity (detection accuracy), the inside is more in a vacuum state. It is desirable to be close to
However, when the inside of the sensor is brought close to a vacuum state, it is necessary to hermetically seal the wiring through hole so that the gas does not leak.
Conventionally, a technique for appropriately hermetically sealing a through hole in such a sensor has been proposed in the following patent documents.
JP 2000-186931 A

  In Patent Document 1, a wiring pattern is formed along an inner wall of a tapered communication hole (through hole) provided in a substrate, and the communication hole is closed on the side surface while maintaining conduction with the wiring pattern. There has been proposed a technique for providing a structure disposed in the box.

However, when performing hermetic sealing using the technique described in Patent Document 1 described above, it is necessary to provide an electrically independent structure for each lead-out wiring, that is, for each through hole. It was difficult to make it easier.
Accordingly, the present invention provides a mechanical quantity sensor that can be miniaturized while performing appropriate hermetic sealing, a wiring board for a mechanical quantity sensor that constitutes the mechanical quantity sensor, and a method of manufacturing the wiring board for the mechanical quantity sensor. The purpose is to provide.

In the first aspect of the present invention, the substrate includes a substrate having a through hole, an electrode disposed in a region including the opening region of the through hole in the substrate, and a conductive member electrically connected to the electrode at least in part. The object is achieved by providing sealing means for sealing the through hole.
According to a second aspect of the present invention, in the mechanical quantity sensor wiring board according to the first aspect, the through hole is formed so that an opening area becomes smaller toward the electrode.
According to a third aspect of the present invention, in the mechanical quantity sensor wiring board according to the first or second aspect, the conductive member is a conductive film formed on an inner wall of the through hole.
According to a fourth aspect of the present invention, in the mechanical quantity sensor wiring board according to the first, second, or third aspect, the sealing means includes a conductive filling member.
According to a fifth aspect of the present invention, in the mechanical quantity sensor wiring board according to the fourth aspect, the surface of the substrate on which the electrode is disposed is polished to the extent that the filling member is exposed. To do.
According to a sixth aspect of the present invention, in the mechanical quantity sensor wiring board according to the fourth or fifth aspect, the surface of the substrate on which the electrode is disposed and the exposed surface of the filling member are substantially flush. As described above, the filling member is polished.
According to the seventh aspect of the present invention, the first step of forming the through hole or the recess in the substrate, and the first step of forming a sealing means for sealing the through hole or the recess having a conductive member at least partially. And the third step of forming an electrode on the surface of the substrate so as to cover the through hole or the recess.
According to an eighth aspect of the present invention, in the method for manufacturing a mechanical quantity sensor wiring board according to the seventh aspect, the first step is such that the opening area of the through hole or the concave portion decreases toward the electrode. It is characterized by forming in.
According to a ninth aspect of the present invention, in the method for manufacturing a mechanical quantity sensor wiring board according to the seventh or eighth aspect, the second step includes forming a conductive film on the inner wall of the through hole or the recess. And a fifth step of filling the through hole or the recess with a filling member.
According to a tenth aspect of the present invention, in the method for manufacturing a mechanical quantity sensor wiring board according to the seventh, eighth, or ninth aspect, the second step is to provide conductivity to at least the through hole or the recess. And a third step of polishing the substrate to such an extent that the filling member is exposed, and the third step is performed on the surface of the substrate polished in the sixth step. The electrode is formed so as to cover at least the exposed region of the conductive member.
According to an eleventh aspect of the present invention, in the method of manufacturing a mechanical quantity sensor wiring board according to the tenth aspect, the sixth step includes polishing so that the polishing surface of the conductive member is substantially flush with the substrate surface. It is characterized by doing.
In a twelfth aspect of the present invention, a movable part including a frame having a hollow part, a weight, and a flexible part that supports the weight in the hollow part of the frame, and the movable part are arranged to face the movable part. Based on a change in the posture of the weight detected by the detection means, a detection means for detecting a change in the posture of the weight based on a change in capacitance between the fixed electrode and the movable portion An output means for outputting a mechanical quantity, wherein the frame is fixed to the wiring board for the mechanical quantity sensor according to any one of claims 1 to 6. The fixed electrode is configured by the electrode provided on the mechanical quantity sensor wiring board, thereby achieving the object.
According to a thirteenth aspect of the present invention, in the mechanical quantity sensor according to the twelfth aspect, the hollow portion of the frame is in a vacuum state.
According to a fourteenth aspect of the present invention, in the mechanical quantity sensor according to the twelfth or thirteenth aspect, the frame and the wiring board for the mechanical quantity sensor are fixed by anodic bonding, and the filling member has an anodic bonding temperature. It is characterized by having a higher melting point.

  According to the present invention, the electrode is provided on the surface of the substrate so as to close the through hole, and the sealing means is provided inside the through hole, so that the airtightness of the sensor can be achieved without using a structure that closes the through hole. The electrode signal can be extracted to the outside while holding the sensor, and a through-hole can be provided in the electrode surface, thereby reducing the size of the sensor.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS.
(1) Outline of Embodiment A mechanical quantity such as acceleration or angular velocity acting on an object is detected based on a change in posture of the weight 13 supported by the beam 12.
The beam 12 is composed of a member that can be easily deformed (bent, warped, bent), such as a silicon substrate. The beam 12 is fixed to the frame 11, and a weight 13 is fixed to the center thereof. When a force such as acceleration or angular velocity acts on the weight 13, the posture of the weight 13 changes.
The posture change of the weight 13 is detected based on the amount of change in capacitance between the weight 13 and the fixed electrodes 21 to 24.

The fixed electrodes 21 to 24 are provided on the inner surface of the upper glass substrate 2 for vacuum-sealing the inside of the sensor. The potentials of the fixed electrodes 21 to 24 are in contact with (connected to) the fixed electrodes 21 to 24. Electrically taken out to the outside of the sensor through the formed via holes 41 to 44.
Via holes 41 to 44 that function as electrical wirings for electrically connecting the inside and outside of the sensor are formed by filling a tapered through hole 60 having a conductive film on the inner wall with a conductive member. Is done.
After forming the via holes 41 to 44, that is, after filling the through hole 60 with the conductive member, the electrode formation surface (arrangement surface) on the upper glass substrate 2 is polished to the extent that the filling member 61 is exposed. Applied.
And each electrode is directly formed in the formation site | part of the via holes 41-44 in the grinding | polishing surface 7 of this upper glass substrate 2, ie, the exposed filling member 61, by means, such as vapor deposition.
As described above, the size can be reduced by forming the fixed electrodes 21 to 24 directly below the via holes 41 to 44.

(2) Details of Embodiment In this embodiment, a capacitance detection type angular velocity sensor (hereinafter referred to as an angular velocity sensor) will be described as an example of a mechanical quantity sensor.
The angular velocity sensor according to the present embodiment is a semiconductor sensor formed by processing a semiconductor substrate.
In the present embodiment, a capacitance detection type angular velocity sensor will be described as an example, but the present embodiment is not limited to this. For example, this applies to general mechanical quantity sensors of a capacitance change detection type such as an acceleration sensor and a pressure sensor.

FIG. 1 is a perspective view showing a schematic structure of an angular velocity sensor according to the present embodiment.
In FIG. 1, in order to express the structure of the angular velocity sensor in an easy-to-understand manner, the structure of each layer is shown separately, but in actuality, each layer is configured in a stacked state.
The angular velocity sensor according to the present embodiment is a semiconductor sensor element formed by processing a semiconductor substrate. The processing of the semiconductor substrate can be performed using MEMS (micro electro mechanical system) technology.

As shown in FIG. 1, the angular velocity sensor has a three-layer structure in which a movable part structure 1 is sandwiched from above and below by an upper glass substrate 2 and a lower glass substrate 3.
The same direction as the stacking direction of the layers in the substrate constituting the angular velocity sensor is defined as the vertical direction, that is, the z-axis (direction). The axes orthogonal to the z-axis and orthogonal to each other are defined as an x-axis (direction) and a y-axis (direction). That is, the x axis, the y axis, and the z axis are three axes that are orthogonal to each other.

FIG. 2A shows a plan view of the movable part structure 1 as viewed from the upper glass substrate 2 side.
As shown in the drawing, in the movable part structure 1, a frame 11, a beam 12, and a weight 13 are formed by etching a silicon substrate.
The frame 11 is a fixed part provided on the peripheral edge of the movable part structure 1 so as to surround the weight 13, and constitutes the framework of the movable part structure 1.
The beams 12 are four strip-shaped thin members extending in the cross direction in the radial direction (in the direction of the frame 11) from the center of the weight 13, and have flexibility.

The weight 13 is composed of a prismatic weight portion 130 located at the center, and prismatic weight portions 131 to 134 that are arranged in a balanced manner at the four corners of the weight portion 130. The weight portions 130 to 134 are integrally formed as a continuous solid.
The weight 13 is a mass body fixed to the frame 11 by four beams 12. The weight 13 can be vibrated or twisted by the force applied from the outside by the action of the beam 12. The weight 13 has conductivity, and its upper surface functions as a movable electrode.

FIG. 2B shows a plan view of the upper glass substrate 2 viewed from the outside (upper side in FIG. 1).
In FIG. 2B, a portion where the upper glass substrate 2 is provided on the outer surface (side opposite to the movable portion structure 1) is indicated by a solid line, and the inner surface of the upper glass substrate 2 (movable portion). A portion provided on the surface facing the structure 1 is indicated by a broken line.
As shown in FIG. 2B, on the inner surface of the upper glass substrate 2, a drive electrode extending in a cross direction along the x-axis and the y-axis with the weight portion 130 as a center at a portion facing the weight portion 130. 20 is provided.
Further, the upper glass substrate 2 has a fixed electrode 21 facing the weight 131, a fixed electrode 22 facing the weight 132, and a fixed electrode 23 facing the weight 133 and the weight 134 facing the weight 133. The fixed electrode 24 is provided in the site | part to perform.

The drive electrode 20 is an electrode for driving the weight 13 to vibrate using an electrostatic force.
The fixed electrodes 21 to 24 are electrodes for detecting an angular velocity acting around the first detection axis (x axis) or the second detection axis (y axis).
In the angular velocity sensor according to the present embodiment, the posture change (displacement) of the weight 13 is detected (measured) based on the change in capacitance between the fixed electrodes 21 to 24 and the movable electrode (weight 13). . The angular velocity acting on the weight 13 is derived based on the detection result (measurement result) of the posture change of the weight.

As shown in FIG. 2B, the upper glass substrate 2 is provided with a via hole 40 for applying the potential of the drive electrode 20 from the outside of the angular velocity sensor.
Similarly, via holes 41 to 44 for taking out the potentials (detection signals) of the fixed electrodes 21 to 24 to the outside of the angular velocity sensor are provided.
The via holes 40 to 44 are provided in a region on the inner side of the bonding region with the frame 11 of the movable part structure 1 in the upper glass substrate 2.
In the angular velocity sensor according to the present embodiment, via holes 40 to 44 are arranged at the center positions of the drive electrode 20 or the fixed electrodes 21 to 24 to which potential is applied (or extracted).
However, the arrangement site of the via holes 40 to 44 is not limited to this, and at least the end portions (openings) of the via holes 40 to 44 are covered (closed) by the drive electrode 20 or the fixed electrodes 21 to 24. What is necessary is just to be arrange | positioned in the possible site | part.

The via holes 40 to 44 are formed along a tapered through hole having an opening area having a smaller diameter from the outside to the inside of the upper glass substrate 2, that is, toward the electrode arrangement surface, and along the inner wall of the through hole. And a conductive filling member filled into the through hole from above the conductive film.
The filling member is made of a highly airtight metal member such as solder or Ag (silver) brazing material, and the melting point thereof is preferably higher than the temperature during anodic bonding.
Further, it is preferable to use a member having higher airtightness (excellent) as the filling member.
The conductive film is preferably composed of a metal film made of a material with good familiarity (wetting properties) of the filling member.
Further, by forming the through hole in a tapered shape, it becomes easy to form a metal film using vacuum deposition from above or sputtering from above.

Further, the upper glass substrate 2 is provided with a via hole 45 for taking out the potential of the movable part structure 1 to the outside of the angular velocity sensor.
Note that the end portions of the via holes 40 to 44 are electrically connected to electrode pads 50 to 54 provided on the periphery of the upper glass substrate 2 through wiring patterns, respectively.
These electrode pads 51 to 54 are connected to a C / V conversion circuit in a signal processing unit (control unit) (not shown).
The upper glass substrate 2 in the angular velocity sensor according to the present embodiment functions as a wiring substrate for taking out an internal signal of the sensor to the outside.

FIG. 3A is a view showing a cross section of the angular velocity sensor in the AA ′ portion shown in FIG.
As shown in the figure, a movable gap 14 for moving the weight 13 is formed between the upper surface of the beam 12 and the weight 13 (the surface facing the upper glass substrate 2) and the upper glass substrate 2. . The upper glass substrate 2 is joined so as to seal the movable gap 14.
A weight is also provided between the lower surface of the beam 12 (the surface facing the lower glass substrate 3) and the bottom surface of the weight 13, that is, the lower surface (the surface facing the lower glass substrate 3) and the lower glass substrate 3, and also at the periphery of the weight 13. A movable gap 15 for making 13 movable is formed. The lower glass substrate 3 is bonded so as to seal the movable gap 15.
Note that the movable gaps 14 and 15 are closer to a vacuum. Thus, by making the inside of the sensor in a vacuum state, the air resistance when the weight 13 operates can be reduced, and the detection sensitivity (detection accuracy) of the angular velocity sensor can be improved.

When forming the frame 11, the beam 12, and the weight 13 of the movable part structure 1, a D-RIE (Deep-Reactive Ion Etching) technique for performing a deep trench etching using a plasma on a silicon substrate is used. And do it.
In the angular velocity sensor according to the present embodiment, the movable part structure 1 is formed using a silicon substrate, but the forming member of the movable part structure 1 is not limited to this. For example, an SOI (silicon on insulator) substrate in which an oxide film is embedded in an intermediate layer of a silicon substrate may be used.
In this case, since the intermediate oxide film layer functions as an etching blocking layer (stop layer) in the etching process when the beam 12 and the weight 13 are processed, the processing accuracy in the thickness direction can be improved.
The upper glass substrate 2 and the lower glass substrate 3 are fixed substrates joined so as to seal the movable part structure 1. The upper glass substrate 2 and the lower glass substrate 3 are bonded to each other by anodic bonding in the frame 11 of the movable part structure 1.

Next, the operation of the angular velocity sensor configured as described above will be described.
As shown in FIG. 1, the angular velocity sensor according to the present embodiment causes the weight 13 to primarily vibrate in the vertical direction (z-axis direction), and generates a Coriolis force on the weight 13 that performs this vibration motion. A method of detecting an angular velocity applied around the first detection axis (x axis) and the second detection axis (y axis) is used.
Specifically, an AC voltage is applied between the drive electrode 20 and the movable electrode (weight 13), and the weight 13 is vibrated in the vertical direction (z-axis direction) using the action of electrostatic force acting between these electrodes.

The frequency of the alternating voltage applied to cause the weight 13 to vibrate up and down, that is, the vibration frequency of the weight 13 is set to a resonance frequency f of about 3 kHz at which the weight 13 resonates and vibrates, for example. Thus, a large displacement amount of the weight 13 can be obtained by vibrating the weight 13 at the resonance frequency f.
When an angular velocity Ω is applied around the mass 13 oscillating at a velocity v, a Coriolis force of “F = 2 mvΩ” is generated at the center of the mass 13 in a direction perpendicular to the movement direction of the mass 13. .
When this Coriolis force F is generated, the weight 13 is twisted and the posture of the weight 13 changes. That is, the weight 13 is inclined with respect to a plane perpendicular to the vibration direction of the weight 13. By detecting changes in the posture of the weight 13 (inclination and twist amount), the direction and magnitude of the acting angular velocity are detected.

FIG. 3B is a diagram showing a state in which the posture of the weight 13 has changed.
For example, when the angular velocity acts around the second detection axis (y-axis) of the weight 13 to generate Coriolis force and the posture of the weight 13 is inclined with respect to the x-axis as shown in FIG. The distance between the electrode and the movable electrode (weight 13) changes.
Specifically, the distance between the fixed electrode 22 and the movable electrode is reduced, while the distance between the fixed electrode 23 and the movable electrode is increased.
Such a change in the distance between the electrodes appears as a change in the capacitance between the electrodes, and the posture change of the weight 13 can be detected based on the change in the capacitance.

A change in the distance between the electrodes, that is, a change in the capacitance between the electrodes is electrically detected using a C / V (capacitance / voltage) conversion circuit in a signal processing unit (control unit) (not shown).
The generated Coriolis force F is detected based on the detected change in the posture of the weight 13 (inclination direction, degree of inclination, etc.). Then, the angular velocity Ω is calculated (derived) based on the detected Coriolis force F. That is, the signal processing unit converts the amount of change in the posture of the weight 13 into an angular velocity.
Here, the case where the angular velocity acts around the second detection axis (y axis) of the weight 13 has been described, but the case where the angular velocity acts around the first detection axis (x axis) of the weight 13 is similarly fixed. The acting angular velocity can be measured by detecting the posture change of the weight 13 based on the change in the distance between the electrode and the movable electrode.

Now, in order to appropriately ensure the detection sensitivity of the angular velocity sensor configured as described above, the configuration of each electrode including the movable gap 14 is an important factor.
In order to improve the detection sensitivity, it is necessary to make the capacitance of each electrode as large as possible. That is, it is desirable that the distance between the electrodes be as small as possible or the area of the electrodes be increased.
However, since the sensor is required to be miniaturized, there is a limit to the expansion of the electrode area. In an actual sensor, for example, the sensitivity is ensured by setting the distance between the electrodes to about 5 μm.
As shown in FIG. 3, in the angular velocity sensor according to the present embodiment, the lower surfaces of the via holes 40 to 44 are also preferably disposed more flatly because each of them serves as a detection electrode or driving electrode arrangement region.
This is because when the bottom surface of the via holes 40 to 44 is concave with respect to the glass substrate 2, the capacitance at that portion is reduced, and when the via holes 40 to 44 are convex, This is because the movable gap 14 at that portion cannot be sufficiently secured and a sufficient drive amount may not be obtained.

Next, a method for manufacturing the angular velocity sensor according to the present embodiment configured as described above will be described.
FIG. 4 is a diagram showing the procedure of the method of manufacturing the angular velocity sensor according to the present embodiment.
FIG. 4 shows a cross section of the angular velocity sensor at the AA ′ portion shown in FIG.
First, a plate-like upper glass substrate 2 as shown in FIG. 4A is prepared (formed).
Then, as shown in FIG. 4B, a tapered through hole (through hole) 60 is formed in a portion of the upper glass substrate 2 where the via holes 40 to 45 are to be formed.
The through hole 60 is formed by using a technique such as sandblasting so that the opening area becomes smaller in diameter from the outer side to the inner side of the upper glass substrate 2, that is, toward the electrode placement surface.
Sand blasting is a technique in which an abrasive (sand) is blown onto a surface of glass or the like together with compressed air.
When manufacturing the angular velocity sensor according to the present embodiment, an etching process is performed by covering the surface of the upper glass substrate 2 with a protective film (mask) from which a portion for forming the through hole 60 is removed.

Next, as shown in FIG. 4C, among the plurality of through holes 60 formed, through holes 60 excluding a portion where the via hole 45 for extracting the potential of the movable part structure 1 to the outside is formed, that is, via holes. Conductive patterns 55, which are conductive films for extracting electric potential, are formed on the inner wall surface of the through-hole 60 in the portion forming 40 to 44 and the outer surface of the upper glass substrate 2 (on the side surface opposite to the movable part structure 1). It is formed by means such as vacuum deposition.
At the same time, the electrode pads 50 to 54 and the wiring pattern connecting the via holes 40 to 44 and the electrode pads 50 to 54 are formed.
Note that the conductive pattern 55, the electrode pads 50 to 54, and the wiring pattern, that is, the conductive film, are formed using a metal of a material adapted to familiarity (wetability) with the filling member 61 described later.
For example, when solder is used for the filling member 61, the conductive film is formed of Cr / Au (chrome / gold). When an Ag (silver) brazing material is used for the filling member 61, the conductive film is formed of Ni (nickel) or the like.

Subsequently, as shown in FIG. 4D, a via hole 45 is formed inside the through hole 60 in which the conductive pattern 55 (conductive film) is formed, that is, the potential of the movable part structure 1 is drawn to the outside. A filling member 61 having conductivity is filled in the through hole 60 excluding the portion.
As the filling member 61, for example, solder, an Ag (silver) brazing material, or the like is used.
The filling member 61 is filled by, for example, disposing (temporarily fixing) a paste-like or ball-like material inside the through-hole 60 and then melting it by performing a heat treatment, so that the conductive pattern 55 ( This is done by blending with a conductive film.
Here, the conductive pattern 55 in the through hole 60 functions as a member for ensuring the familiarity (wetting property) of the filling member 61.

Next, as shown in FIG. 4E, the inner surface of the upper glass substrate 2 (the surface facing the movable part structure 1) is polished to a level (about) at which the filling member 61 is exposed.
Here, the polishing process is performed so that the polishing surface 7 which is the surface of the upper glass substrate 2 and the filling member 61, that is, the inner surface of the upper glass substrate 2 (the surface facing the movable part structure 1) is flat. .
Here, the upper glass substrate 2 is polished by mechanical polishing (lapping) using a polishing liquid containing an abrasive having a fine particle diameter.
Here, the filling member 61 is described so as not to protrude from the lower surface of the glass substrate 2, but is not limited to such a state. For example, the filling member 61 may be protruded from the lower surface of the glass substrate 2 and flattened so as to have the same height as the lower surface of the glass substrate 2 by a polishing process.

After the polishing treatment, as shown in FIG. 4 (f), the drive electrode 20 and the fixed electrodes 21 to 24 are formed on the polishing surface 7 of the upper glass substrate 2.
The drive electrode 20 and the fixed electrodes 21 to 24 are formed by evaporating (stacking) a metal film such as Al (aluminum) or Cr / Ni (chromium / nickel) on the polishing surface 7 of the upper glass substrate. Yes.
Thus, in the angular velocity sensor according to the present embodiment, the drive electrode 20 and the fixed electrodes 21 to 24 are directly and directly deposited on the filling member 61 in the via holes 40 to 44 after the polishing process.

Therefore, conduction between the drive electrode 20 and the fixed electrodes 21 to 24 and the via holes 40 to 44 (conduction pattern 55) can be appropriately (accurately), so that trouble such as conduction failure (contact failure) is generated. Can be suppressed. Thereby, the reliability of the angular velocity sensor can be improved.
Further, by directly connecting the drive electrode 20 and the fixed electrodes 21 to 24 to the via holes 40 to 44, it is possible to omit connection patterns and connection structures between the electrodes and the via holes 40 to 44 that have been conventionally used. Therefore, the angular velocity sensor can be downsized.

Next, as shown in FIG. 4G, the upper glass substrate 2 and the movable part structure 1 formed by etching the silicon substrate are joined.
Specifically, the opposing surface (polishing surface 7) of the movable part structure 1 in the upper glass substrate 2 and the end face of the frame 11 in the movable part structure 1 are anodically bonded.
At this time, anodic bonding is performed so that the opening of the through hole 60 for forming the via hole 45 is completely closed by the end face of the frame 11.
The anodic bonding is a bonding method in which a cathode voltage is applied to the glass substrate (upper glass substrate 2, lower glass substrate 3) side and bonding is performed using electrostatic attraction between glass and silicon.
In addition, the joining method of a glass substrate and the movable part structure 1 is not limited to anodic bonding. For example, eutectic bonding in which metals are laminated on the bonding surface and bonded may be used.

After the upper glass substrate 2 and the movable part structure 1 are joined, as shown in FIG. 4 (h), the inner surface of the through hole 60 for forming the via hole 45, the frame 11 seen through the opening of the through hole 60. A conductive pattern 56 for taking out the potential of the movable part structure 1 is formed on the exposed surface and the outer surface of the upper glass substrate 2 (side surface opposite to the movable part structure 1).
The conductive pattern 56 is made of a conductive film formed continuously on the inner wall surface of the through hole 60, the exposed surface of the frame 11, and the outer surface of the upper glass substrate 2.
The conductive pattern 56 functions as a conductive electrode for the weight 13.
The via hole 45 is completely closed by the end face of the frame 11, so that no gas leaks from the via hole 45. Therefore, it is not necessary to provide a filling member in the through hole 60 of the via hole 45.

Further, although not shown, the angular velocity sensor shown in FIG. 1 is further obtained by anodic bonding the facing surface of the movable part structure 1 in the lower glass substrate 3 and the end face of the frame 11 in the movable part structure 1. Complete.
When the lower glass substrate 3 and the movable part structure 1 are bonded, the inside of the angular velocity sensor (movable gaps 14 and 15) is sealed by anodic bonding so as to be in a vacuum state.
The lower glass substrate 3 may be bonded in advance before the upper glass substrate 2 and the movable part structure 1 are bonded. In this case, the inside of the angular velocity sensor is vacuum-sealed at the stage of FIG.

(Modification)
Next, a modified example of the method for manufacturing the angular velocity sensor described above will be described.
In this modification, a method of forming the via holes 40 to 45 by forming the recesses 70 in the upper glass substrate 2 instead of forming the through holes 60 in the upper glass substrate 2 shown in FIG. .
FIG. 5 is a diagram showing a procedure of a modified example of the manufacturing method of the angular velocity sensor according to the present embodiment. FIG. 5 shows a cross section of the angular velocity sensor taken along the line AA ′ shown in FIG.
Here, parts that are the same as those in the method for manufacturing the angular velocity sensor shown in FIG. 4 described above are assigned the same reference numerals, and detailed descriptions thereof are omitted.
First, a plate-like upper glass substrate 2 as shown in FIG.
Then, as shown in FIG. 5 (b), a tapered recess 70 is formed in a portion of the upper glass substrate 2 where the via holes 40 to 45 are to be formed.
The recess 70 is formed using a technique such as sandblasting so that the opening area becomes smaller in diameter from the outside of the upper glass substrate 2 toward the bottom, that is, toward the electrode placement surface.

Next, as shown in FIG. 5 (c), of the plurality of formed recesses 70, the recesses 70 excluding a part for forming the via hole 45 for drawing out the potential of the movable part structure 1 to the outside, that is, the via holes 40- A conductive pattern 55 ′, which is a conductive film for extracting a potential, is formed on the inner wall surface, the bottom surface, and the outer surface of the upper glass substrate 2 (side surface opposite to the movable portion structure 1).
At the same time, the electrode pads 50 to 54 and the wiring pattern connecting the via holes 40 to 44 and the electrode pads 50 to 54 are formed.
The conductive pattern 55 ′ is made of a conductive film formed continuously on the inner wall surface of the recess 70, the bottom surface of the recess 70, and the outer surface of the upper glass substrate 2.
Note that the conductive pattern 55 ′, the electrode pads 50 to 54, and the wiring pattern, that is, the conductive film are formed using a metal material suitable for the familiarity (wetting property) with the filling member 61.

Subsequently, as shown in FIG. 5D, a via hole 45 is formed in the recess 70 where the conductive pattern 55 ′ (conductive film) is formed, that is, the potential of the movable part structure 1 is drawn to the outside. A filling member 61 having conductivity is filled in the inside of the recess 70 excluding the portion.
As the filling member 61, for example, solder, an Ag (silver) brazing material, or the like is used.
Next, as shown in FIG. 5E, the inner surface of the upper glass substrate 2 (the surface facing the movable part structure 1) is polished to a level (about) at which the filling member 61 is exposed.
That is, the upper glass substrate 2 is polished to at least the bottom of the recess 70 to expose the filling member 61.
Here, the polishing process is performed so that the polishing surface 7 which is the surface of the upper glass substrate 2 and the filling member 61, that is, the inner surface of the upper glass substrate 2 (the surface facing the movable part structure 1) is flat. .

In addition, after the grinding | polishing process of the upper glass substrate 2, the process similar to the process mentioned above shown to FIG.4 (f)-(h) is performed, and an angular velocity sensor is formed.
According to the modified example, when the via holes 40 to 44 are formed, the recess 70 is provided so that the conductive pattern 55 ′ can also be provided on the bottom surface of the recess 70, so the familiarity of the filling member 61 in the recess 70 ( Wettability) can be improved.
Thereby, since the filling member 61 can be filled without providing a gap (space) inside the concave portion 70, it is possible to appropriately perform electrode formation after the polishing process.
Further, since the recess 70 can be formed in a shorter time than the through hole 60, the manufacturing time can be shortened and the cost can be reduced.

According to the present embodiment, the drive electrode 20 and the fixed electrodes 21 to 24 are directly connected to the via holes 40 to 44, that is, the drive electrode 20 and the fixed electrodes 21 to 24 are directly below the via holes 40 to 44. By forming the wiring pattern, the mounting area of the wiring pattern can be minimized, and the angular velocity sensor can be downsized.
According to the present embodiment, before the drive electrode 20 and the fixed electrodes 21 to 24 are formed, each electrode disposition surface (the surface facing the movable part structure 1 in the upper glass substrate 2) is polished, Conductivity between the electrode and the via holes 40 to 44 (conduction pattern 55) can be appropriately taken, and occurrence of poor conduction can be suppressed.
Further, since the angular velocity sensor can be configured with a simple structure, the cost can be reduced.

In the angular velocity sensor according to the present embodiment, the sensor is sealed by filling the via holes 40 to 44 with the conductive filling member 61. However, the sealing method is not limited to this. Absent.
For example, a non-conductive member such as a resin may be filled. However, in this case, it is configured so that electrical contact between each electrode and the conductive film inside the via holes 40 to 44 can be reliably obtained.
In addition, when filling a non-conductive member, a connection line penetrating the via holes 40 to 44 may be separately provided, and an electrical contact between the connection line and each electrode may be ensured. Note that when the connection line is provided, the conductive film in the via holes 41 to 44 can be deleted.

It is the perspective view which showed schematic structure of the angular velocity sensor which concerns on this Embodiment. (A) shows the top view which looked at the movable part structure from the upper glass substrate side, (b) shows the top view which looked at the upper glass substrate from the outer side. (A) is the figure which showed the cross section of the angular velocity sensor in the A-A 'part shown to Fig.2 (a), (b) is the figure which showed the state from which the attitude | position of the weight changed. It is the figure which showed the procedure of the manufacturing method of the angular velocity sensor which concerns on this Embodiment. It is the figure which showed the procedure of the modification of the manufacturing method of the angular velocity sensor which concerns on this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Movable part structure 2 Upper glass substrate 3 Lower glass substrate 7 Polishing surface 11 Frame 12 Beam 13 Weight 14 Movable gap 15 Movable gap 20 Drive electrode 21-24 Fixed electrode 40-45 Via hole 50-54 Electrode pad 55, 56 Conduction pattern 60 Through hole 61 Filling member 70 Recess 130-134 Weight

Claims (14)

A substrate having a through hole;
An electrode disposed in a region including an opening region of the through hole in the substrate;
A sealing member that at least partially includes a conductive member that is electrically connected to the electrode, and seals the through hole;
A wiring board for a mechanical quantity sensor, comprising:   2. The wiring board for a mechanical quantity sensor according to claim 1, wherein the through hole is formed so that an opening area becomes smaller toward the electrode.   3. The mechanical quantity sensor wiring board according to claim 1, wherein the conductive member is a conductive film formed on an inner wall of the through hole.   4. The mechanical quantity sensor wiring board according to claim 1, wherein the sealing means includes a conductive filling member.   5. The wiring board for a mechanical quantity sensor according to claim 4, wherein a surface of the substrate on which the electrode is disposed is polished to such an extent that the filling member is exposed.   The filling member is polished so that a surface of the substrate on which the electrode is disposed and an exposed surface of the filling member are substantially flush with each other. Wiring board for mechanical quantity sensor. A first step of forming a through hole or recess in the substrate;
A second step of forming a sealing means having a conductive member at least in part and sealing the through hole or the recess;
A third step of forming an electrode on the surface of the substrate so as to cover the through hole or the recess;
A method of manufacturing a wiring board for a mechanical quantity sensor, comprising:   The method of manufacturing a wiring board for a mechanical quantity sensor according to claim 7, wherein the first step forms the through hole or the recess so that an opening area becomes smaller toward the electrode. The second step includes
A fourth step of forming a conductive film on the inner wall of the through hole or the recess;
A fifth step of filling the through hole or the recess with a filling member;
The method for manufacturing a wiring board for a mechanical quantity sensor according to claim 7 or 8, characterized by comprising: In the second step, at least the through hole or the concave portion is filled with a conductive filling member,
And a sixth step of polishing the substrate to such an extent that the filling member is exposed.
In the third step, an electrode is formed on the surface of the substrate polished in the sixth step so as to cover at least the exposed region of the filling member. The manufacturing method of the wiring board for mechanical quantity sensors of Claim 9.   The method of manufacturing a wiring board for a mechanical quantity sensor according to claim 10, wherein the sixth step comprises polishing so that a polishing surface of the conductive member is substantially flush with the substrate surface. A frame having a hollow portion;
A movable part composed of a weight and a flexible part that supports the weight in the hollow part of the frame;
A fixed electrode disposed to face the movable part;
Detecting means for detecting a change in the posture of the weight based on a change in capacitance between the fixed electrode and the movable part;
Output means for outputting a mechanical quantity based on a change in the posture of the weight detected by the detection means;
A mechanical quantity sensor comprising:
The frame is fixed to the wiring board for a mechanical quantity sensor according to any one of claims 1 to 6,
The fixed electrode is constituted by the electrode provided on the wiring board for the mechanical quantity sensor.   The mechanical quantity sensor according to claim 12, wherein the hollow portion of the frame is in a vacuum state. The frame and the mechanical quantity sensor wiring board are fixed using anodic bonding,
The mechanical quantity sensor according to claim 12, wherein the filling member has a melting point higher than an anodic bonding temperature.

Images