JP5935332B2 - PHYSICAL QUANTITY SENSOR, MANUFACTURING METHOD FOR PHYSICAL QUANTITY SENSOR, AND ELECTRONIC DEVICE - Google Patents

Description

  The present invention relates to a physical quantity sensor, a method for manufacturing a physical quantity sensor, and an electronic apparatus.

The physical quantity sensor has a fixed electrode that is fixedly arranged and a movable electrode that is opposed to the fixed electrode at a distance and is displaceable, and a capacitance between the fixed electrode and the movable electrode. Based on the above, a physical quantity sensor element that detects physical quantities such as acceleration and angular velocity is known (see, for example, Patent Document 1).
For example, a physical quantity sensor element described in Patent Document 1 includes a substrate, a pair of support members fixed to the substrate, a weight body that includes a movable electrode and can be displaced with respect to the substrate, the weight body, and each support member. And a fixed electrode fixed to the substrate. The substrate is made of a glass substrate, and the support member, weight body, beam member, and fixed electrode are made by etching a single silicon substrate.

In such a physical quantity sensor, a plurality of wirings are formed on a substrate, and each fixed electrode is brought into contact with a predetermined wiring, thereby electrically connecting the wiring and each fixed electrode, and supporting the other wiring with a pillar. It can be considered that the wiring is electrically connected to each movable electrode by bringing the members into contact with each other.
However, each fixed electrode and column member made of a silicon material have a relatively high electrical resistance, and the wiring and each fixed electrode (the same applies to the movable electrode) are electrically connected with a high resistance. Therefore, there is a problem that the characteristics of the physical quantity sensor cannot be stabilized.

JP 2011-169630 A

  An object of the present invention is to provide a physical quantity sensor, a physical quantity sensor manufacturing method, and an electronic apparatus that can exhibit stable device characteristics.

Such an object is achieved by the present invention described below.
The physical quantity sensor of the present invention includes a base substrate,
A movable structure supported above the base substrate and provided with a movable electrode portion,
On the base substrate,
A fixed electrode portion disposed to face the movable electrode portion;
A first wiring electrically connected to the fixed electrode portion;
A second wiring electrically connected to the movable structure,
The movable structure and the fixed electrode portion are provided with an impurity diffusion portion in which impurities are diffused on a joint surface with the base substrate, and are connected to the first wiring and the second wiring through the impurity diffusion portion. It is characterized by.
As a result, the first wiring, the fixed electrode portion, the second wiring, and the movable structure are electrically connected with a low electrical resistance, respectively, so that a physical quantity sensor that can exhibit stable device characteristics is obtained.

In the physical quantity sensor according to the aspect of the invention, it is preferable that the impurity diffusion portion is provided over the entire area of the movable structure and the surface of the fixed electrode portion facing the base substrate.
This eliminates the need for selective formation of the impurity diffusion portion, and facilitates formation of the impurity diffusion portion.
In the physical quantity sensor according to the aspect of the invention, it is preferable that the impurity diffusion portion is provided over the entire surface of the movable structure and the fixed electrode portion on the side opposite to the base substrate.
Thereby, bending of a fixed electrode part and a movable structure can be suppressed.

In the physical quantity sensor according to the aspect of the invention, it is preferable that the impurity diffusion portion is provided in a region that overlaps the base substrate in a plan view among surfaces of the movable structure and the fixed electrode portion that face the base substrate. .
Thereby, the total area of the impurity diffusion part can be suppressed. Moreover, the bending of the fixed electrode portion and the movable structure can be suppressed.

In the physical quantity sensor according to the aspect of the invention, it is preferable that the impurity diffusion portion is provided at a contact portion between the fixed electrode portion and the first wiring and a contact portion between the movable structure and the second wiring.
Thereby, the total area of the impurity diffusion part can be suppressed. Moreover, the bending of the fixed electrode portion and the movable structure can be suppressed.

In the physical quantity sensor according to the aspect of the invention, it is preferable that the movable structure and the fixed electrode portion are formed of a single member.
Thereby, for example, a fixed member and a movable structure can be easily formed by patterning a single member by etching or the like.
In the physical quantity sensor of the present invention, the movable structure and the fixed electrode portion are made of a semiconductor material,
The impurity diffused in the impurity diffusion part is preferably at least one of boron and phosphorus.
Thereby, an impurity diffusion part with low electric resistance can be formed easily.

In the physical quantity sensor of the present invention, the base substrate is made of a material containing alkali metal ions,
It is preferable that the fixed electrode portion and the movable structure are bonded to the base substrate by an anodic bonding method.
Thereby, the bending of a fixed electrode part can be suppressed effectively.
In the physical quantity sensor according to the aspect of the invention, it is preferable that the fixed electrode portion is supported by the base substrate over the entire area facing the base substrate.
Thereby, a fixed electrode part, a movable structure, and a base substrate can be joined firmly.

The physical quantity sensor manufacturing method of the present invention includes a first substrate on which a first wiring and a second wiring are formed, and a second substrate on which an impurity diffusion portion in which impurities are diffused is formed on at least a part of a main surface. A preparation process to prepare;
A bonding step of bringing the impurity diffusion portion into contact with the first wiring and the second wiring and bonding a second substrate to the main surface of the first substrate;
Etching the second substrate to form a movable structure having a movable electrode portion and a fixed electrode portion disposed to face the movable electrode portion.
Thereby, a physical quantity sensor capable of exhibiting stable device characteristics can be easily manufactured.
An electronic apparatus according to the present invention includes the physical quantity sensor according to the present invention.
Thereby, an electronic device having excellent reliability can be obtained.
The physical quantity sensor of the present invention includes a base substrate and a movable structure that is supported above the base substrate and includes a movable electrode portion, and the movable electrode portion is disposed on the base substrate. The movable electrode is provided with a fixed electrode portion disposed opposite to the first wire, a first wire electrically connected to the fixed electrode portion, and a second wire electrically connected to the movable structure. The body and the fixed electrode portion are provided with an impurity diffusion portion in which impurities are diffused on a joint surface with the base substrate, and are connected to the first wiring and the second wiring through the impurity diffusion portion, and the impurity The diffusion portion is provided in a region of the surface of the movable structure and the fixed electrode portion facing the base substrate that overlaps the base substrate in plan view.
The physical quantity sensor of the present invention includes a base substrate and a movable structure that is supported above the base substrate and includes a movable electrode portion, and the movable electrode portion is disposed on the base substrate. The movable electrode is provided with a fixed electrode portion disposed opposite to the first wire, a first wire electrically connected to the fixed electrode portion, and a second wire electrically connected to the movable structure. The body and the fixed electrode portion are provided with an impurity diffusion portion in which impurities are diffused on a joint surface with the base substrate, and are connected to the first wiring and the second wiring through the impurity diffusion portion, and the impurity The diffusion portion is provided at a contact portion between the fixed electrode portion and the first wiring and at a contact portion between the movable structure and the second wiring.
The physical quantity sensor of the present invention includes a base substrate and a movable structure that is supported above the base substrate and includes a movable electrode portion, and the movable electrode portion is disposed on the base substrate. The movable electrode is provided with a fixed electrode portion disposed opposite to the first wire, a first wire electrically connected to the fixed electrode portion, and a second wire electrically connected to the movable structure. The body and the fixed electrode portion are provided with an impurity diffusion portion in which impurities are diffused on a joint surface with the base substrate, and are connected to the first wiring and the second wiring through the impurity diffusion portion, The base substrate is made of a material containing alkali metal ions, and the fixed electrode portion and the movable structure are directly bonded to the base substrate.
The physical quantity sensor of the present invention includes a base substrate and a movable structure that is supported above the base substrate and includes a movable electrode portion, and the movable electrode portion is disposed on the base substrate. The movable electrode is provided with a fixed electrode portion disposed opposite to the first wire, a first wire electrically connected to the fixed electrode portion, and a second wire electrically connected to the movable structure. The body and the fixed electrode portion are provided with an impurity diffusion portion in which impurities are diffused on a joint surface with the base substrate, and are connected to the first wiring and the second wiring through the impurity diffusion portion, The fixed electrode portion is characterized in that the entire area of the surface facing the base substrate is supported by the base substrate.

It is a perspective view which shows the physical quantity sensor which concerns on 1st Embodiment of this invention. It is a top view which shows the physical quantity sensor shown in FIG. It is the sectional view on the AA line in FIG. It is the elements on larger scale (partial expanded sectional view) of FIG. It is the BB sectional view taken on the line in FIG. It is the elements on larger scale (partial expanded sectional view) of FIG. It is sectional drawing for demonstrating the manufacturing method of the physical quantity sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the physical quantity sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the physical quantity sensor shown in FIG. It is sectional drawing which shows the physical quantity sensor which concerns on 2nd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the physical quantity sensor shown in FIG. It is sectional drawing which shows the physical quantity sensor which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the physical quantity sensor which concerns on 3rd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the physical quantity sensor shown in FIG. It is sectional drawing which shows the physical quantity sensor which concerns on 4th Embodiment of this invention. It is sectional drawing which shows the physical quantity sensor which concerns on 4th Embodiment of this invention. It is sectional drawing which shows the physical quantity sensor which concerns on 5th Embodiment of this invention. It is sectional drawing which shows the physical quantity sensor which concerns on 5th Embodiment of this invention. It is a schematic diagram which shows an example of the sensor apparatus to which the physical quantity sensor of this invention is applied. It is an electronic device (notebook type personal computer) of the present invention. It is the electronic device (cellular phone) of the present invention. It is an electronic apparatus (digital still camera) of the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Preferred embodiments of a physical quantity sensor, a physical quantity sensor manufacturing method, and an electronic apparatus according to the invention are described below with reference to the accompanying drawings.
<First Embodiment>
First, a first embodiment of the physical quantity sensor of the present invention will be described.
1 is a perspective view showing a physical quantity sensor according to a first embodiment of the present invention, FIG. 2 is a plan view showing the physical quantity sensor shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA in FIG. 4 is a partially enlarged view (partially enlarged sectional view) of FIG. 3, FIG. 5 is a sectional view taken along line BB in FIG. 2, and FIG. 6 is a partially enlarged view (partial enlarged sectional view) of FIG. .

  In the following, for convenience of explanation, the front side of the paper in FIG. 2 is referred to as “up”, the back side of the paper is referred to as “down”, the right side is referred to as “right”, and the left side is referred to as “left”. 1 to 3 show an X axis, a Y axis, and a Z axis as three axes orthogonal to each other. In the following, the direction parallel to the X axis (left-right direction) is the “X-axis direction”, the direction parallel to the Y-axis is “Y-axis direction”, and the direction parallel to the Z-axis (vertical direction) is “Z-axis direction”. " 1 to 3, for convenience of explanation, illustration of an insulating film 9 to be described later and the corresponding film is omitted. In the present embodiment, an example in which the physical quantity sensor is used as a physical quantity sensor element for measuring physical quantities such as acceleration and angular velocity will be described.

[Physical quantity sensor]
A physical quantity sensor 1 shown in FIGS. 1 and 2 includes a base substrate 2 that is an insulating substrate, an element piece (base body) 3 bonded and supported to the base substrate 2, and a conductor that is electrically connected to the element piece 3. The pattern 4 and the lid member 5 provided so as to cover the element piece 3 are included. Hereinafter, each part which comprises the physical quantity sensor 1 is demonstrated in detail sequentially.

(Base substrate)
The base substrate 2 has a function of supporting the element piece 3. The base substrate 2 has a plate shape, and a cavity 21 is provided on the upper surface (one surface). The cavity 21 is formed so as to include a movable portion 33, movable electrode portions 36 and 37, and connecting portions 34 and 35 of an element piece 3 to be described later when the base substrate 2 is viewed in plan view. Have Such a cavity 21 constitutes an escape portion that prevents the movable portion 33, the movable electrode portions 36 and 37, and the coupling portions 34 and 35 of the element piece 3 from contacting the base substrate 2. Thereby, the displacement of the movable part 33 of the element piece 3 can be permitted.
The escape portion may be an opening that penetrates the base substrate 2 in the thickness direction instead of the cavity portion 21 (concave portion). In the present embodiment, the shape of the cavity 21 in plan view is a quadrangle (specifically, a rectangle), but is not limited thereto.

  Further, on the upper surface of the base substrate 2, recesses 22, 23, and 24 are provided along the outer periphery of the cavity 21 described above. The recesses 22, 23 and 24 have a shape corresponding to the conductor pattern 4 in plan view. Specifically, the recess 22 has a shape corresponding to a wiring 41 and an electrode 44 of a conductor pattern 4 described later, and the recess 23 has a shape corresponding to a wiring 42 and an electrode 45 of a conductor pattern 4 described later. 24 has a shape corresponding to the wiring 43 and the electrode 46 of the conductor pattern 4 to be described later.

The depth of the portion of the recess 22 where the electrode 44 is provided is deeper than the portion of the recess 22 where the wiring 41 is provided. Similarly, the depth of the portion of the recess 23 where the electrode 45 is provided is deeper than the portion of the recess 23 where the wiring 42 is provided. The depth of the portion of the recess 24 where the electrode 46 is provided is deeper than the portion of the recess 24 where the wiring 43 is provided.
By increasing the depth of a part of the recesses 22, 23, and 24 in this way, when the substrate 103 before forming the element piece 3 is bonded to the substrate 102 </ b> A at the time of manufacturing the physical quantity sensor 1 described later, It is possible to prevent the substrate 103 from being bonded to the electrodes 44, 45, and 46.

  Specifically, it is preferable to use a high-resistance silicon material or glass material as the constituent material of the base substrate 2. In particular, when the element piece 3 is composed of a silicon material as a main material, an alkali is used. It is preferable to use a glass material containing metal ions (mobile ions) (for example, borosilicate glass such as Pyrex glass (registered trademark)). Thereby, when the element piece 3 is composed of silicon as a main material, the base substrate 2 and the element piece 3 can be anodically bonded.

  Further, it is preferable that the constituent material of the base substrate 2 has as little difference in thermal expansion coefficient as that of the constituent material of the element piece 3. Specifically, the heat between the constituent material of the base substrate 2 and the constituent material of the element piece 3 is preferable. The difference in expansion coefficient is preferably 3 ppm / ° C. or less. As a result, even when the base substrate 2 and the element piece 3 are subjected to a high temperature during bonding, the residual stress between the base substrate 2 and the element piece 3 can be reduced.

(Element piece)
The element piece 3 is composed of a movable structure 3 ′ and fixed electrode portions 38 and 39. The movable structure 3 ′ includes a pair of fixed portions 31 and 32, a movable portion 33 including movable electrode portions 36 and 37, and a pair of connecting portions 34 that connect the fixed portions 31 and 32 and the movable portion 33, 35. The fixed portions 31 and 32, the movable portion 33, the movable electrode portions 36 and 37, and the connecting portions 34 and 35 are integrally formed.

  Such an element piece 3 is formed in the X-axis direction while the movable portion 33 (movable electrode portions 36 and 37) elastically deforms the connecting portions 34 and 35 in accordance with changes in physical quantities such as acceleration and angular velocity. Displace. With such displacement, the size of the gap between the movable electrode portion 36 and the fixed electrode portion 38 and the size of the gap between the movable electrode portion 37 and the fixed electrode portion 39 change. That is, with such a displacement, the capacitance between the movable electrode portion 36 and the fixed electrode portion 38 and the capacitance between the movable electrode portion 37 and the fixed electrode portion 39 are respectively reduced. Change. Therefore, physical quantities such as acceleration and angular velocity can be detected based on these capacitances.

The fixing portions 31 and 32 are respectively bonded to the upper surface of the base substrate 2 described above. Specifically, the fixing portion 31 is bonded to a portion on the −X direction side with respect to the cavity portion 21 on the upper surface of the base substrate 2, and the fixing portion 32 is connected to the cavity portion 21 on the upper surface of the base substrate 2. Are joined to the + X direction side. Further, the fixing portions 31 and 32 are provided so as to straddle the outer peripheral edge of the cavity portion 21 when viewed in plan. The positions and shapes of the fixing portions 31 and 32 are determined according to the positions and shapes of the connecting portions 34 and 35, the conductor pattern 4, and the like, and are not limited to those described above.
A movable portion 33 is provided between the two fixed portions 31 and 32. In the present embodiment, the movable part 33 has a longitudinal shape extending in the X-axis direction. The shape of the movable portion 33 is determined according to the shape, size, etc. of each portion constituting the element piece 3 and is not limited to the above-described one.

  The movable portion 33 is connected to the fixed portion 31 via the connecting portion 34 and is connected to the fixed portion 32 via the connecting portion 35. More specifically, the left end portion of the movable portion 33 is connected to the fixed portion 31 via the connecting portion 34, and the right end portion of the movable portion 33 is connected to the fixed portion 32 via the connecting portion 35. Has been.

The connecting portions 34 and 35 connect the movable portion 33 to the fixed portions 31 and 32 so as to be displaceable. In the present embodiment, the connecting portions 34 and 35 are configured to be able to displace the movable portion 33 in the X-axis direction (+ X direction or −X direction) as indicated by an arrow a in FIG.
Specifically, the connecting portion 34 includes two beams 341 and 342. Each of the beams 341 and 342 has a shape extending in the X-axis direction while meandering in the Y-axis direction. In other words, each of the beams 341 and 342 has a shape that is folded back a plurality of times (three times in the present embodiment) in the Y-axis direction. Note that the number of times the beams 341 and 342 are folded may be one or two times, or four or more times.

Similarly, the connecting portion 35 is composed of two beams 351 and 352 having a shape extending in the X-axis direction while meandering in the Y-axis direction.
The connecting parts 34 and 35 are not limited to those described above as long as they support the movable part 33 so as to be displaceable with respect to the base substrate 2. You may be comprised with a pair of beam each extended in a Y direction.

Thus, the movable electrode portion 36 is provided on one side (+ Y direction side) in the width direction of the movable portion 33 supported so as to be displaceable in the X-axis direction with respect to the base substrate 2, and the other side (−Y On the direction side, a movable electrode portion 37 is provided.
The movable electrode portion 36 includes a plurality of movable electrode fingers 361 to 365 that protrude in the + Y direction from the movable portion 33 and are arranged in a comb-teeth shape. The movable electrode fingers 361, 362, 363, 364, 365 are arranged in this order from the −X direction side to the + X direction side. Similarly, the movable electrode portion 37 includes a plurality of movable electrode fingers 371 to 375 that protrude from the movable portion 33 in the −Y direction and are arranged in a comb-teeth shape. The movable electrode fingers 371, 372, 373, 374, and 375 are arranged in this order from the −X direction side to the + X direction side.

Thus, the plurality of movable electrode fingers 361 to 365 and the plurality of movable electrode fingers 371 to 375 are provided side by side in the direction in which the movable portion 33 is displaced. Thereby, the electrostatic capacitance between the fixed electrode fingers 382, 384, 386, and 388, which will be described later, and the movable electrode portion 36, and the electrostatic capacitance between the fixed electrode fingers 381, 383, 385, 387 and the movable electrode portion 36 are described. Can be efficiently changed according to the displacement of the movable portion 33. Similarly, capacitance between fixed electrode fingers 392, 394, 396, and 398 and the movable electrode portion 36, which will be described later, and capacitance between fixed electrode fingers 391, 393, 395, and 397 and the movable electrode portion 36, respectively. Can be efficiently changed according to the displacement of the movable portion 33. Therefore, when the physical quantity sensor 1 is used as a physical quantity sensor element, the detection accuracy can be excellent.
Such a movable electrode part 36 is opposed to the fixed electrode part 38 with an interval. Further, the movable electrode portion 37 faces the fixed electrode portion 39 with a space therebetween.

  The fixed electrode unit 38 includes a plurality of fixed electrode fingers 381 to 388 arranged in a comb-like shape that meshes with the plurality of movable electrode fingers 361 to 365 of the movable electrode unit 36 described above at intervals. The end portions of the plurality of fixed electrode fingers 381 to 388 on the side opposite to the movable portion 33 are respectively joined to the + Y direction side portion with respect to the cavity portion 21 on the upper surface of the base substrate 2. The fixed electrode fingers 381 to 388 each have a fixed end as a fixed end and a free end extending in the −Y direction.

  The fixed electrode fingers 381 to 388 are arranged in this order from the −X direction side to the + X direction side. The fixed electrode fingers 381 and 382 make a pair, and the above-mentioned movable electrode fingers 361 and 362 form a pair, and the fixed electrode fingers 383 and 384 make a pair and the movable electrode fingers 362 and 363 form a fixed electrode. The fingers 385 and 386 make a pair, and are provided between the movable electrode fingers 363 and 364, and the fixed electrode fingers 387 and 388 make a pair and face the movable electrode fingers 364 and 365.

  Here, the fixed electrode fingers 382, 384, 386, and 388 are first fixed electrode fingers, respectively, and the fixed electrode fingers 381, 383, 385, and 387 are the first fixed electrode fingers on the base substrate 2, respectively. The second fixed electrode fingers are spaced apart from each other via a gap (gap). As described above, the plurality of fixed electrode fingers 381 to 388 are composed of a plurality of first fixed electrode fingers and a plurality of second fixed electrode fingers arranged alternately. In other words, the first fixed electrode finger is arranged on one side of the movable electrode finger, and the second fixed electrode finger is arranged on the other side.

  The first fixed electrode fingers 382, 384, 386 and 388 and the second fixed electrode fingers 381, 383, 385 and 387 are separated from each other on the base substrate 2. In other words, the first fixed electrode fingers 382, 384, 386, 388 and the second fixed electrode fingers 381, 383, 385, 387 are not connected to each other on the base substrate 2 and are isolated in an island shape. . Thereby, the first fixed electrode fingers 382, 384, 386, 388 and the second fixed electrode fingers 381, 383, 385, 387 can be electrically insulated. Therefore, the capacitance between the first fixed electrode fingers 382, 384, 386 and 388 and the movable electrode portion 36, and between the second fixed electrode fingers 381, 383, 385 and 387 and the movable electrode portion 36. The capacitance can be measured separately, and the physical quantity can be detected with high accuracy based on the measurement results.

  In the present embodiment, the fixed electrode fingers 381 to 388 are separated from each other on the base substrate 2. In other words, the fixed electrode fingers 381 to 388 are not connected to each other on the base substrate 2 and are isolated in an island shape. Accordingly, the lengths of the fixed electrode fingers 381 to 388 in the Y-axis direction can be made uniform. Therefore, it is possible to reduce the size of the fixed electrode fingers 381 to 388 while securing an area necessary for obtaining a sufficient bonding strength of each bonded portion between the fixed electrode fingers 381 to 388 and the base substrate 2. Therefore, the physical quantity sensor 1 can be downsized while the impact resistance of the physical quantity sensor 1 is excellent.

  Similarly, the fixed electrode portion 39 includes a plurality of fixed electrode fingers 391 to 398 arranged in a comb-like shape that meshes with the plurality of movable electrode fingers 371 to 375 of the movable electrode portion 37 described above at intervals. . The ends of the plurality of fixed electrode fingers 391 to 398 on the side opposite to the movable portion 33 are respectively joined to the portion on the −Y direction side with respect to the cavity portion 21 on the upper surface of the base substrate 2. Each fixed electrode finger 391 to 398 has a fixed end as a fixed end and a free end extending in the + Y direction.

  The fixed electrode fingers 391 to 398 are arranged in this order from the −X direction side to the + X direction side. The fixed electrode fingers 391 and 392 make a pair, and the fixed electrode fingers 393 and 394 make a pair between the movable electrode fingers 371 and 372. The fingers 395 and 396 make a pair, and are provided between the movable electrode fingers 373 and 374, and the fixed electrode fingers 397 and 398 make a pair and face the movable electrode fingers 374 and 375.

  Here, the fixed electrode fingers 392, 394, 396, and 398 are first fixed electrode fingers, respectively, and the fixed electrode fingers 391, 393, 395, and 397 are the first fixed electrode fingers on the base substrate 2, respectively. The second fixed electrode fingers are spaced apart from each other via a gap (gap). As described above, the plurality of fixed electrode fingers 391 to 398 are composed of a plurality of first fixed electrode fingers and a plurality of second fixed electrode fingers arranged alternately. In other words, the first fixed electrode finger is arranged on one side of the movable electrode finger, and the second fixed electrode finger is arranged on the other side.

  The first fixed electrode fingers 392, 394, 396, and 398 and the second fixed electrode fingers 391, 393, 395, and 397 are separated from each other on the base substrate 2 like the fixed electrode portion 38 described above. . As a result, the capacitance between the first fixed electrode fingers 392, 394, 396, and 398 and the movable electrode portion 37, and between the second fixed electrode fingers 391, 393, 395, and 397 and the movable electrode portion 37 are obtained. Can be measured separately, and the physical quantity can be detected with high accuracy based on the measurement results.

  In the present embodiment, the plurality of fixed electrode fingers 391 to 398 are separated from each other on the base substrate 2 in the same manner as the fixed electrode portion 38 described above. Accordingly, it is possible to reduce the size of the fixed electrode fingers 391 to 398 while ensuring a sufficient area of each joint between the fixed electrode fingers 391 to 398 and the base substrate 2. Therefore, the physical quantity sensor 1 can be downsized while the impact resistance of the physical quantity sensor 1 is excellent.

Such an element piece 3 (fixed portions 31, 32, movable portion 33, connecting portions 34, 35, a plurality of fixed electrode fingers 381-388, 391-398 and a plurality of movable electrode fingers 361-365, 371-375) This is formed by etching one substrate 103 described later.
Accordingly, the thicknesses of the fixed portions 31 and 32, the movable portion 33, the connecting portions 34 and 35, the plurality of fixed electrode fingers 381 to 388 and 391 to 398, and the plurality of movable electrode fingers 361 to 365 and 371 to 375 are increased. be able to. Also, these thicknesses can be easily and accurately aligned. For this reason, it is possible to increase the sensitivity of the physical quantity sensor 1 and to improve the impact resistance of the physical quantity sensor 1.

In addition, the constituent material of the element piece 3 is not particularly limited as long as the physical quantity can be detected based on the change in capacitance as described above, but a semiconductor is preferable, and specifically, for example, single crystal silicon It is preferable to use a silicon material such as polysilicon.
That is, the fixed portions 31 and 32, the movable portion 33, the connecting portions 34 and 35, the plurality of fixed electrode fingers 381 to 388 and 391 to 398, and the plurality of movable electrode fingers 361 to 365 and 371 to 375 are mainly made of silicon. It is preferable that it is constituted as a material.

  Silicon can be processed with high precision by etching. Therefore, the element piece 3 is made of silicon as a main material, whereby the dimensional accuracy of the element piece 3 is improved, and as a result, the physical quantity sensor 1 that is a physical quantity sensor element can be highly sensitive. Moreover, since silicon is less fatigued, the durability of the physical quantity sensor 1 can be improved.

  Further, as described above, the element piece 3 is supported by the base substrate 2 by bonding the fixed portions 31 and 32 and the fixed electrode portions 38 and 39 to the upper surface of the base substrate 2. In the present embodiment, the base substrate 2 and the element piece 3 are bonded via an insulating film 9 described later. The bonding method of the element piece 3 (specifically, the fixing portions 31 and 32 and the fixed electrode fingers 381 to 388 and 391 to 398 described above) and the base substrate 2 is not particularly limited, but is an anodic bonding method. Is preferably used. Accordingly, the fixed portions 31 and 32 and the fixed electrode portions 38 and 39 (respective fixed electrode fingers 381 to 388 and 391 to 398) can be firmly bonded to the base substrate 2. Therefore, the impact resistance of the physical quantity sensor 1 can be improved. Further, the fixed portions 31 and 32 and the fixed electrode portions 38 and 39 can be bonded to desired positions on the base substrate 2 with high accuracy. Therefore, it is possible to increase the sensitivity of the physical quantity sensor 1 that is a physical quantity sensor element. In this case, as described above, the element piece 3 is made of silicon as a main material, and the base substrate 2 is made of a glass material containing alkali metal ions.

The configuration of the element piece 3 has been described above. As shown in FIG. 3, impurities diffused in the entire region of the lower surface (joint surface with the base substrate 2) of such element piece 3 (movable structure 3 ′ and fixed electrode portions 38 and 39). A diffusion portion 30 is formed.
For example, when the element piece 3 is made of a silicon material, the impurity diffusion portion 30 can be formed by diffusing impurities such as boron and phosphorus on the lower surface of the element piece 3. By forming such an impurity diffusion portion 30, the conductivity of the element piece 3 can be improved. In particular, by using boron, phosphorus, or the like as described above as an impurity, the impurity diffusion portion 30 can be easily formed, and the conductivity of the element piece 3 can be effectively improved. The method for forming the impurity diffusion portion 30, that is, the method for diffusing the impurity into the element piece 3 is not particularly limited, and for example, a thermal diffusion method, an ion implantation method, or the like can be used.
Further, the diffusion amount (doping amount) of the impurity into the element piece 3 is not particularly limited, but is preferably 1.0 × 10 ²⁰ atoms / cc or more. Thereby, the electrical resistance of the impurity diffusion part 30 can be made smaller.

Such an element piece 3 is electrically connected to the conductor pattern 4 (wirings 41, 42, and 43 described later) through the impurity diffusion portion 30. Therefore, the element piece 3 and the conductor pattern 4 are electrically connected with a relatively low electrical resistance, in other words, with a low electrical resistance compared to the case where the impurity diffusion portion 30 is not formed. The characteristics can be stabilized.
In the present embodiment, as described above, the impurity diffusion portion 30 is formed over the entire lower surface of the element piece 3. Thereby, it is not necessary to selectively form the impurity diffusion portion 30, so that the impurity diffusion portion 30 can be easily formed.

(Conductor pattern)
The conductor pattern 4 is provided on the upper surface of the base substrate 2 described above. As shown in FIG. 2, the conductor pattern 4 includes wirings 41, 42, and 43 and electrodes 44, 45, and 46.
The wiring (first wiring) 41 is provided outside the cavity portion 21 of the base substrate 2 described above, and is formed along the outer periphery of the cavity portion 21. One end of the wiring 41 is connected to the electrode 44 on the outer peripheral portion of the upper surface of the base substrate 2.

  Such wiring 41 is electrically connected to the fixed electrode fingers 382, 384, 386 and 388 and the fixed electrode fingers 392, 394, 396 and 398 which are the first fixed electrode fingers of the element piece 3. As described above, since the impurity diffusion portion 30 is formed on the lower surface of each fixed electrode finger 382, 384, 386, 388, 392, 394, 396, 398, each of these fixed electrode fingers 382, 384, 386, 388, 392, 394, 396, 398 and the wiring 41 are electrically connected with a low electric resistance (contact resistance).

Further, the wiring (first wiring) 42 is provided along the outer peripheral edge inside the wiring 41 described above and outside the hollow portion 21 of the base substrate 2 described above. One end portion of the wiring 42 is connected to the electrode 45 on the outer peripheral portion of the upper surface of the base substrate 2 so as to be arranged at a distance from the electrode 44 described above.
Such a wiring 42 is electrically connected to each fixed electrode finger 381, 383, 385, 387 and each fixed electrode finger 391, 393, 395, 397 which are the second fixed electrode fingers of the element piece 3. As described above, since the impurity diffusion portion 30 is formed on the lower surface of each fixed electrode finger 381, 383, 385, 387, 391, 393, 395, 397, each of these fixed electrode fingers 381, 383, 385, 387, 391, 393, 395, 397 and the wiring 42 are electrically connected with low electrical resistance.

The wiring (second wiring) 43 is provided so as to extend from the joint portion with the fixed portion 31 on the base substrate 2 to the outer peripheral portion of the upper surface of the base substrate 2. The end portion of the wiring 43 opposite to the fixing portion 31 is arranged on the outer peripheral portion of the upper surface of the base substrate 2 (the lid member 5 on the base substrate 2 so as to be arranged at a distance from the electrodes 44 and 45 described above. The electrode 46 is connected to the outer portion of the electrode 46.
Such a wiring 43 is electrically connected to the fixing portion 31 of the element piece 3. As described above, since the impurity diffusion portion 30 is formed on the lower surface of the fixed portion 31, the fixed portion 31 and the wiring 43 are electrically connected with a low electric resistance.

The material of the wirings 41 to 43 is not particularly limited as long as it has conductivity, and various electrode materials can be used. For example, ITO (Indium Tin Oxide), IZO (IZO ( Indium Zinc Oxide), In ₃ O ₃ , SnO ₂ , Sb-containing SnO ₂ , oxides (transparent electrode materials) such as Al-containing ZnO, Au, Pt, Ag, Cu, Al or alloys containing these, etc. One or more of these can be used in combination.

Among these, it is preferable to use a transparent electrode material (particularly ITO) as a constituent material of the wirings 41 to 43. When the wirings 41 and 42 are each made of a transparent electrode material, when the base substrate 2 is a transparent substrate, foreign matter or the like existing on the surface of the base substrate 2 on the fixed electrode portions 38 and 39 side is removed. It can be easily visually recognized from the surface opposite to the fixed electrode portions 38 and 39. Therefore, the physical quantity sensor 1 can be provided more reliably as a highly sensitive physical quantity sensor element.
In addition, the constituent materials of the electrodes 44 to 46 are not particularly limited as long as they have electrical conductivity as in the case of the wirings 41 to 43 described above, and various electrode materials can be used. In the present embodiment, the same material as that of protrusions 471, 472, 481, and 482 described later is used as the constituent material of the electrodes 44 to 46.

  Since the wirings 41 and 42 are provided on the upper surface of the base substrate 2, the electrostatic capacitance between the first fixed electrode fingers 382, 384, 386 and 388 and the movable electrode part 36 via the wiring 41. The electrostatic capacity between the first fixed electrode fingers 392, 394, 396, 398 and the movable electrode portion 37 is measured, and the second fixed electrode fingers 381, 383, 385, 387 and the movable electrode are connected via the wiring 42. It is possible to measure the capacitance between the unit 36 and the capacitance between the second fixed electrode fingers 391, 393, 395, 397 and the movable electrode unit 37.

In the present embodiment, by using the electrode 44 and the electrode 46, the capacitance between the first fixed electrode fingers 382, 384, 386 and 388 and the movable electrode portion 36 and the first fixed electrode fingers 392, 394 and 396 are used. 398 and the movable electrode part 37 can be measured. Further, by using the electrode 45 and the electrode 46, the capacitance between the second fixed electrode fingers 381, 383, 385, 387 and the movable electrode portion 36 and the second fixed electrode fingers 391, 393, 395, 397 The capacitance between the movable electrode portion 37 can be measured.
In addition, since the wirings 41 and 42 are provided on the upper surface of the base substrate 2, electrical connection to the fixed electrode portions 38 and 39 and positioning thereof are easy. Therefore, the reliability (especially impact resistance and detection accuracy) of the physical quantity sensor 1 can be improved.

  Further, the wiring 41 and the electrode 44 are provided in the recess 22 of the base substrate 2 described above, the wiring 42 and the electrode 45 are provided in the recess 23 of the base substrate 2 described above, and the wiring 43 and the electrode 46 are described above. The base substrate 2 is provided in the recess 24. Thereby, it is possible to prevent the wirings 41 to 43 from protruding from the plate surface of the base substrate 2. Therefore, the fixed electrode fingers 382, 384, 386, 388, 392, 394, 398, and the wiring 41 are secured while ensuring the bonding between the fixed electrode fingers 381 to 388 and 391 to 398 and the base substrate 2. Electrical connection and electrical connection between the fixed electrode fingers 381, 383, 385, 387, 391, 393, 395, 397 and the wiring 42 can be performed. Similarly, the fixed portion 31 and the wiring 43 can be electrically connected while ensuring the bonding between the fixed portion 31 and the base substrate 2.

Here, it is preferable to satisfy the relationship of t <d, where t is the thickness of each of the wirings 41 to 43 and d is the depth of each of the recesses 22 to 24 where the wiring 41 is provided.
In particular, a plurality of conductive protrusions 481 and a plurality of protrusions 482 are provided on the wiring 41. The plurality of protrusions 481 are provided corresponding to the fixed electrode fingers 382, 384, 386, and 388, and the plurality of protrusions 482 are provided corresponding to the fixed electrode fingers 392, 394, 396, and 398. The fixed electrode fingers 382, 384, 386 and 388 and the wiring 41 are electrically connected via the protrusion 481, and the fixed electrode fingers 392, 394, 396 and 398 and the wiring 41 are connected via the protrusion 482. Electrically connected. Thereby, the electrical connection between each fixed electrode finger 382, 384, 386, 388, 392, 394, 396, and 398 and the wiring 41 is prevented while preventing the unintentional electrical connection (short circuit) between the wiring 41 and other parts. Connection can be made.

Similarly, a plurality of conductive protrusions 471 and a plurality of protrusions 472 are provided on the wiring 42. The plurality of protrusions 471 are provided corresponding to the fixed electrode fingers 381, 383, 385, and 387, and the plurality of protrusions 472 are provided corresponding to the fixed electrode fingers 391, 393, 395, and 397. The fixed electrode fingers 381, 383, 385, 387 and the wiring 42 are electrically connected via the protrusion 471, and the fixed electrode fingers 391, 393, 395, 397 and the wiring 42 are connected via the protrusion 472. Electrically connected. This prevents the electrical connection between each of the fixed electrode fingers 381, 383, 385, 387, 391, 393, 395, and 397 and the wiring 42 while preventing the unintentional electrical connection between the wiring 42 and other parts. It can be carried out.
Similarly, a conductive protrusion 50 is provided on the wiring 43. The protrusion 50 is provided corresponding to the fixing portion 31. The fixing portion 31 and the wiring 43 are electrically connected via the protrusion 50. Thereby, the electrical connection between the fixing portion 31 and the wiring 43 can be performed while preventing the unintentional electrical connection between the wiring 43 and other parts.

  The constituent material of the projections 471, 472, 481, 482, 50 is not particularly limited as long as it has conductivity, and various electrode materials can be used. For example, Au, Pt Metals such as simple metals such as Ag, Cu, and Al or alloys containing them are preferably used. By forming the protrusions 471, 472, 481, 482, 50 using such a metal, the contact resistance between the wirings 41, 42, 43 and the fixed electrode portions 38, 39, the fixed portion 31 can be reduced. Can do.

Further, the thicknesses of the wirings 41 to 43 are each t, the depths of the portions of the recesses 22 to 24 where the wiring 41 is provided are d, and the heights of the protrusions 471, 472, 481, and 482 are h. , It is preferable to satisfy the relationship d≈t + h.
An insulating film 9 is provided on the wirings 41 to 43. The insulating film 9 on the protrusions 471, 472, 481, 482, 50 described above is not formed, and the surface of the protrusion is exposed. The insulating film 9 has a function of preventing unintentional electrical connection between the conductor pattern 4 and the element piece 3.

  In the present embodiment, the insulating film 9 is formed over substantially the entire upper surface of the base substrate 2 except for the formation regions of projections 471, 472, 481, 482, 50 and electrodes 44 to 46 described later. The formation region of the insulating film 9 is not limited to this as long as it can cover the wirings 41 to 43. For example, the bonding portion with the element piece 3 on the upper surface of the base substrate 2 or the bonding portion with the lid member 5 is used. The shape may be excluded.

  Moreover, it is preferable to satisfy the relationship of d> t, where t is the thickness of each of the wirings 41 to 43 and d is the depth of each of the recesses 22 to 24 where the wiring 41 is provided. Thereby, for example, as shown in FIG. 4, a gap 221 is formed between the fixed electrode finger 391 and the insulating film 9 on the wiring 41. Although not shown, a gap similar to the gap 221 is also formed between the other fixed electrode fingers and the insulating film 9 on the wirings 41 and 42. Such a gap is similarly formed between the substrate 102 and the substrate 103 in the manufacture of the physical quantity sensor 1 to be described later, and gas generated during anodic bonding can be discharged.

  Further, as shown in FIG. 6, a gap 222 is formed between the lid member 5 and the insulating film 9 on the wiring 43. Although not shown, a gap similar to the gap 222 is also formed between the lid member 5 and the insulating film 9 on the wirings 41 and 42. These gaps can be used to depressurize the inside of the lid member 5 or to fill with an inert gas. Note that these gaps may be closed with an adhesive when the lid member 5 and the base substrate 2 are bonded together with the adhesive.

The constituent material of the insulating film 9 is not particularly limited, and various insulating materials can be used. However, the base substrate 2 is a glass material (particularly, a glass material to which alkali metal ions are added). If configured, silicon dioxide (SiO ₂ ) is preferably used. As a result, unintentional electrical connection as described above is prevented, and the base substrate 2 and the element piece 3 can be connected to each other even if the insulating film 9 is present at the junction with the element piece 3 on the upper surface of the base substrate 2. Can be anodically bonded.

  Moreover, the thickness (average thickness) of the insulating film 9 is not particularly limited, but is preferably about 10 to 1000 nm, and more preferably about 10 to 200 nm. When the insulating film 9 is formed in such a thickness range, the unintentional electrical connection as described above can be prevented. Further, when the base substrate 2 is made of a glass material containing alkali metal ions and the element piece 3 is made of silicon as a main material, an insulating film is formed at a bonding portion with the element piece 3 on the upper surface of the base substrate 2. Even if 9 is present, the base substrate 2 and the element piece 3 can be anodically bonded via the insulating film 9.

(Cover member)
The lid member 5 has a function of protecting the element piece 3 described above.
The lid member 5 has a plate shape, and a concave portion 51 is provided on one surface (lower surface) thereof. The recess 51 is formed to allow displacement of the movable portion 33 and the movable electrode portions 36 and 37 of the element piece 3.
And the part outside the recessed part 51 of the lower surface of the cover member 5 is joined to the upper surface of the base substrate 2 mentioned above. In the present embodiment, the base substrate 2 and the lid member 5 are bonded via the insulating film 9 described above.

The method for bonding the lid member 5 and the base substrate 2 is not particularly limited, and for example, a bonding method using an adhesive, an anodic bonding method, a direct bonding method, or the like can be used.
Further, the constituent material of the lid member 5 is not particularly limited as long as it can exhibit the functions as described above, and for example, a silicon material, a glass material, or the like can be suitably used.

[Method of manufacturing physical quantity sensor]
Next, the manufacturing method of the physical quantity sensor of this invention is demonstrated. In the following, an example of manufacturing the above-described physical quantity sensor 1 will be described.
7-9 is sectional drawing for demonstrating the manufacturing method of the physical quantity sensor 1 shown in FIG. 1, respectively. 7 to 9 each show a cross section corresponding to the cross section taken along the line BB in FIG. Hereinafter, a case where the base substrate 2 is made of a glass material containing alkali metal ions and the element piece 3 is made of silicon will be described as an example.

  The physical quantity sensor 1 is manufactured by preparing a first substrate 102A on which the conductor pattern 4 is formed and a second substrate 103 on which an impurity diffusion portion 30 in which impurities are diffused is formed on at least a part of the main surface. A bonding step of bringing the impurity diffusion portion 30 into contact with the conductor pattern 4 to bond the second substrate 103 to the main surface of the first substrate 102A, and etching the second substrate 103 to move the movable structure 3 ′ and the movable structure 3 ′. And an etching process for forming fixed electrode portions 38 and 39 arranged to face the electrode portions 36 and 37. Details will be described below.

[1] Preparation Step [1-1] Base Substrate Manufacturing Step First, as shown in FIG. 7A, a substrate 102 as a first substrate is prepared. This substrate 102 becomes the base substrate 2 through the steps described later. The substrate 102 is made of a glass material containing an alkali metal.

Next, as shown in FIG. 7B, the upper surface of the substrate 102 is etched to form the cavity 21 and the recesses 22 and 23. At this time, although not shown in FIG. 7B, the recess 24 is also formed by the etching. Thereby, the substrate 102A in which the cavity 21 and the recesses 22 to 24 are formed is obtained.
The method for forming the cavity 21 and the recesses 22 to 24 is not particularly limited. For example, physical etching methods such as plasma etching and beam etching, chemical etching such as reactive ion etching, photo-assisted etching, and wet etching. One or more of the methods can be used in combination. Note that the same method can be used for etching in the following steps.

In the etching as described above, for example, a mask formed by a photolithography method can be preferably used. In addition, the cavity 21 and the recesses 22 to 24 can be formed in order by repeating mask formation, etching, and mask removal a plurality of times. The mask is removed after etching. As a method for removing the mask, for example, when the mask is made of a resist material, a resist stripping solution is used. When the mask is made of a metal material, a metal stripping solution such as a phosphoric acid solution is used. be able to.
In addition, as a mask, you may form the cavity part 21 and the recessed parts 22-24 (a several recessed part from which depth differs) collectively, for example by using a gray scale mask.
Next, as shown in FIG. 7C, the conductor pattern 4 is formed on the upper surface of the substrate 102A. Thereafter, although not shown in FIG. 7C, an insulating film is formed. Here, the insulating film becomes the insulating film 9 after being separated into individual pieces to be described later.

[1-2] Second Substrate Preparation Step First, as shown in FIG. 7D, a substrate 103 as a second substrate is prepared. The substrate 103 becomes the element piece 3 through thinning, patterning, and individualization as will be described later. The substrate 103 is a silicon substrate. Further, the thickness of the substrate 103 is larger than the thickness of the element piece 3. Thereby, the handleability of the substrate 103 can be improved. The thickness of the substrate 103 may be the same as the thickness of the element piece 3. In this case, the thinning process described later may be omitted.
Next, as shown in FIG. 7E, boron (impurities) is diffused throughout the lower surface (one surface) of the substrate 103, and the impurity diffusion portion 30 is formed on the lower surface side of the substrate 103. Examples of the boron diffusion method include a thermal diffusion method and an ion implantation method, but it is preferable to use the thermal diffusion method. Thereby, the impurity diffusion part 30 can be formed easily.

[2] Joining Step First, as shown in FIG. 8A, on the upper surface of the substrate 102A on which the conductor pattern 4 and the insulating film 9 obtained in the step [1-1] described above are formed, the step [1- 2] is placed so that the impurity diffusion portion 30 is located on the substrate 102A side. Next, the substrate 103 is bonded to the substrate 102A by an anodic bonding method. Thereby, the board | substrate 103 and each protrusion 471,472,50 are connected.
Next, the substrate 103 is thinned from the upper surface side to obtain a substrate 103A as shown in FIG. This thinning is performed so that the thickness of the substrate 103A is the same as the thickness of the element piece 3. Further, a method for thinning the substrate 103 is not particularly limited, but for example, a CMP method or a dry polishing method can be preferably used.

[3] Etching Step Next, the element piece 3 is obtained by etching the substrate 103A as shown in FIG. The etching method is not particularly limited, and various etchings as described above can be used.
[4] Lid Arrangement Step Next, as shown in FIG. 9A, the lid member 105 having the recess 51 is joined to the upper surface of the substrate 102A. Thereby, the joined body 101 is obtained in which the substrate 102A and the lid member 105 are joined so as to accommodate the element piece 3. The lid member 105 becomes the lid member 5 after being separated into individual pieces to be described later.

[5] Individualization Step Next, the physical quantity sensor 1 is obtained by dividing the joined body 101 into individual pieces (dicing) as shown in FIG.
According to the manufacturing method of the physical quantity sensor 1 according to the first embodiment described above, it is possible to easily form the element piece 3 having the impurity diffusion portion 30, and therefore to facilitate the manufacture of the physical quantity sensor 1. Can do.

Second Embodiment
Next, a second embodiment of the physical quantity sensor of the present invention will be described.
FIG. 10 is a cross-sectional view showing a physical quantity sensor according to the second embodiment of the present invention, and FIG. 11 is a cross-sectional view for explaining a method of manufacturing the physical quantity sensor shown in FIG. 10 and 11 show cross sections corresponding to the cross section taken along the line AA in FIG.

The physical quantity sensor according to the present embodiment is the same as the physical quantity sensor according to the first embodiment described above except that the configuration (formation position) of the impurity diffusion portion is different.
In the following description, the physical quantity sensor of the second embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted. Moreover, in FIG. 10, the same code | symbol is attached | subjected about the structure similar to 1st Embodiment mentioned above.

(Physical quantity sensor)
In the physical quantity sensor 1A of the present embodiment, the impurity diffusion portion 30 is formed not only on the entire lower surface of the element piece 3 but also on the entire upper surface. Here, when the impurity diffusion part 30 is formed only on the lower surface of the element piece 3 as in the first embodiment, tensile stress is generated in the impurity diffusion part 30 and the element piece 3 is bent in the Z direction. There is. Therefore, as in the present embodiment, by forming the impurity diffusion portions 30 on both the lower surface and the upper surface of the element piece 3, the tensile stress generated in the impurity diffusion portion 30 on the lower surface side and the impurity diffusion portion 30 on the upper surface side. It is possible to cancel the tensile stress generated in the element piece 3 and to effectively prevent the element piece 3 from being bent. As a result, the overlap between the movable electrode portions 36 and 37 and the fixed electrode portions 38 and 39 is eliminated, and the physical quantity sensor 1A can exhibit desired characteristics.

(Manufacturing method of physical quantity sensor)
Next, a manufacturing method of the physical quantity sensor 1A will be described. The manufacturing method of the present embodiment is the same as the manufacturing method of the first embodiment described above except that [2] the bonding process is different. Therefore, below, the description is abbreviate | omitted about only a joining process and another process.

[2] Bonding Step First, as shown in FIG. 11A, the substrate 103 is placed on the upper surface of the substrate 102A on which the conductor pattern 4 and the insulating film 9 are formed, and the impurity diffusion portion 30 is located on the substrate 102A side. Placed on. Next, the substrate 103 is bonded to the substrate 102A by an anodic bonding method. Thereby, the board | substrate 103 and each protrusion 471,472,50 are connected.

Next, the substrate 103 is thinned from the upper surface side to obtain a substrate 103A as shown in FIG. This thinning is performed so that the thickness of the substrate 103A is the same as the thickness of the element piece 3.
Next, boron (impurities) is diffused over the entire upper surface of the substrate 103A, and the impurity diffusion portion 30 is formed on the upper surface side of the substrate 103A. Examples of the boron diffusion method include a thermal diffusion method and an ion implantation method, but it is preferable to use the ion implantation method. Thereby, the impurity diffusion part 30 can be formed easily. Note that, when the thermal diffusion method is used, the substrate 102A may be melted or deformed by heat in the process, and thus the occurrence of such a problem is surely prevented by using the ion implantation method. You can also
Also by the physical quantity sensor 1A according to the second embodiment as described above, the same effects as those of the physical quantity sensor 1 according to the first embodiment described above can be exhibited.

<Third Embodiment>
Next, a third embodiment of the physical quantity sensor of the present invention will be described.
12 and 13 are cross-sectional views showing a physical quantity sensor according to the third embodiment of the present invention, and FIG. 14 is a cross-sectional view for explaining a method of manufacturing the physical quantity sensor shown in FIG. 12 and 14 show a cross section corresponding to the cross section taken along the line AA in FIG. 2, and FIG. 13 shows a cross section corresponding to the cross section taken along the line BB in FIG.

The physical quantity sensor according to the present embodiment is the same as the physical quantity sensor according to the first embodiment described above except that the configuration (formation position) of the impurity diffusion portion is different.
In the following description, the physical quantity sensor of the third embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted. 12 and 13, the same reference numerals are given to the same configurations as those of the first embodiment described above.

(Physical quantity sensor)
As shown in FIGS. 12 and 13, in the physical quantity sensor 1 </ b> B of the present embodiment, an impurity diffusion portion 30 is formed in a region overlapping the base substrate 2 on the lower surface of the element piece 3. Specifically, the impurity diffusion portion 30 is formed on the lower surface of the base end portion of each of the fixed electrode fingers 381 to 388 and 391 to 398 and the lower surface of the fixed portion 31.

  By forming the impurity diffusion part 30 in such a region, the formation region (total area) of the impurity diffusion part 30 is suppressed to be small, and the occurrence of the bending of the element piece 3 as described in the second embodiment is prevented. The fixed electrode fingers 382, 384, 386, 388, 392, 394, 396, 398 and the wiring 41, the fixed electrode fingers 381, 383, 385, 387, 391, 393, 395 can be effectively suppressed. 397 and the wiring 42, and the fixing portion 31 and the wiring 43 can be reliably electrically connected via the impurity diffusion portion 30. As a result, the physical quantity sensor 1B can exhibit desired characteristics and stabilize the characteristics.

(Manufacturing method of physical quantity sensor)
Next, a manufacturing method of the physical quantity sensor 1B will be described. The manufacturing method of the present embodiment is the same as the manufacturing method of the first embodiment described above except that [1-2] second substrate preparation process is different. Therefore, in the following description, only the second substrate preparation process is described, and the description of the other processes is omitted.

[1-2] Second Substrate Preparation Step First, as shown in FIG. 14A, a substrate 103 as a second substrate is prepared. The substrate 103 becomes the element piece 3 through thinning, patterning, and individualization as will be described later. The thickness of the substrate 103 is thicker than the thickness of the element piece 3.

Next, as shown in FIG. 14B, the lower surface of the substrate 103, which overlaps with the base substrate 2 in a subsequent bonding step, in other words, the fixed electrode fingers 381 to 388 and 391 to 398. Boron (impurities) is diffused into the region to be the base end portion and the region to be the fixing portion 31, and the impurity diffusion portion 30 is selectively formed on the lower surface side of the substrate 103.
The physical quantity sensor 1B according to the third embodiment as described above can also exhibit the same effects as those of the physical quantity sensor 1 according to the first embodiment described above.

<Fourth embodiment>
Next, a fourth embodiment of the physical quantity sensor of the present invention will be described.
15 and 16 are cross-sectional views showing a physical quantity sensor according to the fourth embodiment of the present invention, respectively. 15 shows a cross section corresponding to FIG. 4, and FIG. 16 shows a cross section corresponding to FIG.

The physical quantity sensor according to the present embodiment is the same as the physical quantity sensor according to the first embodiment described above except that the configuration (formation position) of the impurity diffusion portion is different.
In the following description, the physical quantity sensor according to the fourth embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted. In FIG. 15, the same reference numerals are given to the same configurations as those of the first embodiment described above.

(Physical quantity sensor)
As shown in FIGS. 15 and 16, in the physical quantity sensor 1 </ b> C of the present embodiment, regions (wirings 41, 42, 43) that overlap with the protrusions 471, 472, 481, 482, 50 on the lower surface of the element piece 3. The impurity diffusion portion 30 is formed at the contact portion). Specifically, the impurity diffusion part 30 is formed on a part of the lower surface of the base end part of each of the fixed electrode fingers 381 to 388 and 391 to 398 and a part of the lower surface of the fixed part 31.

  By forming the impurity diffusion portion 30 in such a region, the formation region (total area) of the impurity diffusion portion 30 is further reduced, and the occurrence of the bending of the element piece 3 as described in the second embodiment is prevented. The fixed electrode fingers 382, 384, 386, 388, 392, 394, 396, 398 and the wiring 41, the fixed electrode fingers 381, 383, 385, 387, 391, 393, 395 can be effectively suppressed. 397 and the wiring 42, and the fixing portion 31 and the wiring 43 can be reliably electrically connected via the impurity diffusion portion 30. As a result, the physical quantity sensor 1 </ b> C can exhibit desired characteristics and stabilize characteristics.

Note that, according to the configuration of the present embodiment, the positioning accuracy of the formation region of the impurity diffusion portion 30 is required to be higher than that of the third embodiment described above, but the formation region of the impurity diffusion portion 30 is more than that of the third embodiment. Therefore, the effect can be exhibited more significantly than in the third embodiment.
Also by the physical quantity sensor 1C according to the fourth embodiment as described above, the same effects as those of the physical quantity sensor 1 according to the first embodiment described above can be exhibited.

<Fifth Embodiment>
Next, a fifth embodiment of the physical quantity sensor of the invention will be described.
17 and 18 are sectional views showing a physical quantity sensor according to the fifth embodiment of the present invention. 17 shows a cross section corresponding to the cross section taken along line AA in FIG. 2, and FIG. 18 shows a cross section corresponding to the cross section taken along line BB in FIG.

The physical quantity sensor according to the present embodiment is the same as the physical quantity sensor according to the first embodiment described above except that the configuration (shape) of the base substrate 2 is different.
In the following description, the physical quantity sensor of the fifth embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted. In FIGS. 17 and 18, the same reference numerals are given to the same configurations as those of the first embodiment described above.

(Physical quantity sensor)
As shown in FIGS. 17 and 18, in the physical quantity sensor 1D of the present embodiment, the distal ends of the fixed electrode fingers 381 to 388 and 391 to 398 are not free ends, and the entire region is supported by the base substrate 2D ( Have been joined). That is, the base substrate 2D has protrusions 29D that protrude into the cavity 21 and have shapes corresponding to the fixed electrode fingers 381 to 388 and 391 to 398. The protrusions 29D and the corresponding fixed electrode fingers It is joined.

Thereby, for example, it is possible to effectively prevent the bending of the fixed electrode fingers 381 to 388 and 391 to 398 due to the tensile stress generated in the impurity diffusion portion 30 as described in the second embodiment. it can. As a result, the physical quantity sensor 1D can exhibit desired characteristics and stabilize the characteristics. Further, by being supported by the base substrate 2D, the strength of the fixed electrode fingers 381 to 388 and 391 to 398 is reinforced, and the physical quantity sensor 1D having more excellent durability is obtained.
Also by the physical quantity sensor 1D according to the fifth embodiment as described above, the same effects as those of the physical quantity sensor 1 according to the first embodiment described above can be exhibited.

(Sensor device)
Next, an example of a sensor device to which the physical quantity sensor of the present invention is applied will be described with reference to FIG.
A sensor device 200 illustrated in FIG. 19 includes the physical quantity sensor 1 described above and an electronic component 201 that is electrically connected to the physical quantity sensor 1.
The electronic component 201 is, for example, an integrated circuit element (IC) and has a function of driving the physical quantity sensor 1. By forming an angular velocity detection circuit or an acceleration detection circuit in the electronic component 201, the sensor device 200 can be configured as a gyro sensor or an acceleration sensor.

Note that FIG. 19 illustrates the case where the sensor device 200 includes one physical quantity sensor 1, but the sensor apparatus 200 may include a plurality of physical quantity sensors 1. The sensor device 200 may include the physical quantity sensor 1 and a physical quantity sensor having a configuration different from that of the physical quantity sensor 1.
Since such a sensor device 200 includes the physical quantity sensor 1 having excellent sensitivity and impact resistance, the sensor device 200 has excellent reliability.

(Electronics)
Next, the electronic apparatus of the present invention will be described.
FIG. 20 is a perspective view showing a configuration of a mobile (or notebook) personal computer to which the electronic apparatus of the present invention is applied.
In this figure, a personal computer 1100 includes a main body 1104 having a keyboard 1102 and a display unit 1106. The display unit 1106 is supported by the main body 1104 via a hinge structure so as to be rotatable. Yes.
Such a personal computer 1100 incorporates a physical quantity sensor 1.

FIG. 21 is a perspective view showing a configuration of a mobile phone (including PHS) to which the electronic apparatus of the invention is applied.
In this figure, a cellular phone 1200 includes an antenna (not shown), a plurality of operation buttons 1202, an earpiece 1204, and a mouthpiece 1206, and a display unit is disposed between the operation buttons 1202 and the earpiece 1204. Has been.
Such a cellular phone 1200 incorporates a physical quantity sensor 1.

FIG. 22 is a perspective view showing the configuration of a digital still camera to which the electronic apparatus of the present invention is applied. In this figure, connection with an external device is also simply shown.
Here, an ordinary camera sensitizes a silver halide photographic film with a light image of a subject, whereas a digital still camera 1300 photoelectrically converts a light image of a subject with an imaging device such as a CCD (Charge Coupled Device). An imaging signal (image signal) is generated.

A display unit is provided on the back of a case (body) 1302 in the digital still camera 1300, and is configured to display based on an imaging signal from the CCD. The display unit is a finder that displays an object as an electronic image. Function.
A light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided on the front side (the back side in the drawing) of the case 1302.
When the photographer confirms the subject image displayed on the display unit and presses the shutter button 1306, the CCD image pickup signal at that time is transferred and stored in the memory 1308.

In the digital still camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side surface of the case 1302. As shown in the figure, a television monitor 1430 is connected to the video signal output terminal 1312 and a personal computer 1440 is connected to the input / output terminal 1314 for data communication as necessary. Further, the imaging signal stored in the memory 1308 is output to the television monitor 1430 or the personal computer 1440 by a predetermined operation.
Such a digital still camera 1300 incorporates a physical quantity sensor 1.
Such an electronic device includes the physical quantity sensor 1 excellent in high sensitivity and impact resistance, and thus has excellent reliability.

  In addition to the personal computer (mobile personal computer) in FIG. 20, the mobile phone in FIG. 21, and the digital still camera in FIG. 22, the electronic apparatus of the present invention includes, for example, an ink jet type ejection device (for example, an ink jet printer), Laptop personal computer, TV, video camera, video tape recorder, car navigation device, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic game device, word processor, workstation, video phone, crime prevention TV monitor, electronic binoculars, POS terminal, medical equipment (for example, electronic thermometer, blood pressure monitor, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic endoscope), fish detector, various measuring devices, instruments (for example, Vehicle, aircraft, ship instrumentation), fly It can be applied to a simulator or the like.

The physical quantity sensor, the method for manufacturing the physical quantity sensor, and the electronic device of the present invention have been described based on the illustrated embodiments, but the present invention is not limited to these.
For example, if the fixed electrode part is separated on the base substrate from at least one fixed electrode finger of the plurality of fixed electrode fingers arranged in a comb-tooth shape on the base substrate, the above-described embodiment It is not limited to.

Further, the number, arrangement, size, and the like of the plurality of fixed electrode fingers of the fixed electrode portion and the plurality of movable electrode fingers of the movable electrode portion provided so as to mesh with the fixed electrode fingers are not limited to the above-described embodiments. .
Further, the movable part may be configured to be displaced in the Y-axis direction, or the movable part may be configured to be rotated around an axis parallel to the X-axis. In this case, the physical quantity may be detected based on the change in capacitance due to the change in the facing area between the movable electrode finger and the fixed electrode finger.

  1, 1A, 1B, 1C, 1D ... Physical quantity sensor 2, 2D ... Base substrate 3 ... Element piece 3 '... Movable structure 4 ... Conductor pattern 5 ... Lid member 21 ... Hollow part 22 ... Recess 221 ... Clearance 222 ... Clearance 23 ... Recess 24 ... Recess 29D ... Projection 30 ... Impurity diffusion part 31 ... Fixed part 32 ... Fixed part 33 ... Movable part 34 ... Connection part 341 342 ... Beam 35 ... Connection part 351, 352 ... Beam 36 ... Movable electrode part 361-365 ... Movable electrode finger 37 ... Movable electrode part 371-375 ... Movable electrode finger 38 ... Fixed electrode part 381 ... 388 Electrode 45 ... Electrode 45 ... Electrode 46 ... Electrode 471 ... Projection Electrode 45 ... Electrode 46 ... Electrode 471 ... Electrode 471 ... Electrode 45 ... Electrode 45 ... Electrode 46 ... Electrode 471 ... Projection 472 ... Protrusion 481 ... Protrusion 482 ... Protrusion 50 ... Protrusion 51 ... Recess 9 ... Insulating film 101 ... Bonded body 102 ... Substrate 102A ... Substrate 103 ... Substrate 103A ... Substrate 105 ... Lid Components 200 ... Sensor device 201 ... Electronic parts 1100 ... Personal computer 1102 ... Keyboard 1104 ... Main body 1106 ... Display unit 1200 ... Mobile phone 1202 ... Operation buttons 1204 ... Earpiece 1206 ... Transmission 1300 Digital still camera 1302 Case 1304 Light receiving unit 1306 Shutter button 1308 Memory 1312 Video signal output terminal 1314 Input / output terminal 1430 Television monitor 1440 Personal computer

Claims (10)

A base substrate;
A movable structure supported above the base substrate and provided with a movable electrode portion,
On the base substrate,
A fixed electrode portion disposed to face the movable electrode portion;
A first wiring electrically connected to the fixed electrode portion;
A second wiring electrically connected to the movable structure,
The movable structure and the fixed electrode portion are provided with an impurity diffusion portion in which impurities are diffused on a joint surface with the base substrate, and are connected to the first wiring and the second wiring through the impurity diffusion portion. ,
The physical quantity sensor , wherein the impurity diffusion portion is provided in a region of the surface of the movable structure and the fixed electrode portion facing the base substrate that overlaps the base substrate in plan view . A base substrate;
A movable structure supported above the base substrate and provided with a movable electrode portion,
On the base substrate,
A fixed electrode portion disposed to face the movable electrode portion;
A first wiring electrically connected to the fixed electrode portion;
A second wiring electrically connected to the movable structure,
The movable structure and the fixed electrode portion are provided with an impurity diffusion portion in which impurities are diffused on a joint surface with the base substrate, and are connected to the first wiring and the second wiring through the impurity diffusion portion. ,
The physical quantity sensor , wherein the impurity diffusion portion is provided at a contact portion between the fixed electrode portion and the first wiring and a contact portion between the movable structure and the second wiring . A base substrate;
A movable structure supported above the base substrate and provided with a movable electrode portion,
On the base substrate,
A fixed electrode portion disposed to face the movable electrode portion;
A first wiring electrically connected to the fixed electrode portion;
A second wiring electrically connected to the movable structure,
The movable structure and the fixed electrode portion are provided with an impurity diffusion portion in which impurities are diffused on a joint surface with the base substrate, and are connected to the first wiring and the second wiring through the impurity diffusion portion. And
The base substrate is made of a material containing alkali metal ions,
The physical quantity sensor, wherein the fixed electrode portion and the movable structure are directly bonded to the base substrate . A base substrate;
A movable structure supported above the base substrate and provided with a movable electrode portion,
On the base substrate,
A fixed electrode portion disposed to face the movable electrode portion;
A first wiring electrically connected to the fixed electrode portion;
A second wiring electrically connected to the movable structure,
The movable structure and the fixed electrode portion are provided with an impurity diffusion portion in which impurities are diffused on a joint surface with the base substrate, and are connected to the first wiring and the second wiring through the impurity diffusion portion. And
In the physical quantity sensor , the fixed electrode portion is supported by the base substrate over the entire area facing the base substrate . 5. The physical quantity sensor according to claim 1, wherein the impurity diffusion portion is provided over the entire surface of the movable structure and the fixed electrode portion facing the base substrate. 6.   The physical quantity sensor according to claim 5, wherein the impurity diffusion portion is provided on the entire area of the movable structure and the surface of the fixed electrode portion opposite to the base substrate. The physical quantity sensor according to any one of claims 1 to 6 , wherein the movable structure and the fixed electrode portion are formed of a single member. The movable structure and the fixed electrode portion are made of a semiconductor material,
Impurity diffused in the impurity diffusion section, boron, physical quantity sensor according to any one of claims 1 at least is one of the phosphorus 7. A preparatory step of preparing a first substrate on which the first wiring and the second wiring are formed, and a second substrate on which an impurity diffusion portion in which impurities are diffused is formed on at least a part of the main surface;
A bonding step of bringing the impurity diffusion portion into contact with the first wiring and the second wiring and bonding a second substrate to the main surface of the first substrate;
Etching the second substrate to form a movable structure having a movable electrode portion and a fixed electrode portion disposed opposite to the movable electrode portion, and a physical quantity sensor comprising: Manufacturing method. An electronic apparatus comprising the physical quantity sensor according to any one of claims 1 to 8.

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