JP6369200B2 - Physical quantity sensor, electronic device and mobile object - Google Patents

Description

  The present invention relates to a physical quantity sensor, an electronic device, and a moving object.

  Conventionally, a physical quantity sensor that detects a physical quantity such as angular velocity and acceleration is known (for example, Patent Document 1).

  The physical quantity sensor described in Patent Document 1 includes a semiconductor substrate, two sensor elements provided on the semiconductor substrate, each having a movable electrode, a fixed electrode provided to face the movable electrode, a movable electrode, and a fixed electrode. A plurality of wirings connected to each other, and a plurality of pads that are electrically connected to the wirings and function as conductive parts that are electrically connected to the outside. Each wiring and each pad is provided on a semiconductor substrate.

  Such a physical quantity sensor is generally used by bonding a sealing member that houses each sensor element to the upper surface of a semiconductor substrate. Thereby, the sensor element can be sealed in the airtight space.

  By the way, in the physical quantity sensor described in Patent Document 1, when each sensor element is sealed by the sealing member as described above, each pad is arranged outside the sealing member in a plan view of the semiconductor substrate, It is necessary to draw out the wiring to the outside of the sealing member.

  In this case, since a part of the pad and the wiring is located outside the sealing member, it is necessary to sufficiently increase the size of the semiconductor substrate. As a result, the entire physical quantity sensor becomes large. Thus, it is difficult to reduce the size of the physical quantity sensor described in Patent Document 1.

Japanese Patent No. 412938

  An object of the present invention is to provide a physical quantity sensor, an electronic device, and a moving body that can be miniaturized.

Such an object is achieved by the present invention described below.
[Application Example 1]
The physical quantity sensor of the present invention includes a support substrate,
A sensor element provided on the support substrate;
A first layer and a second layer having conductivity; and a third layer having an insulating property and positioned between the first layer and the second layer, and the sensor element of the support substrate. A sealing substrate that is bonded to the side surface and seals the sensor element;
A conductive portion provided on the opposite side of the surface to be bonded to the support substrate of the sealing substrate and electrically connected to the sensor element ;
The first layer, the third layer, and the second layer are laminated in this order from the support substrate side,
The sealing substrate has a through hole that penetrates the second layer and the third layer and reaches the first layer,
The conductive portion is disposed in the through hole,
The conductive portion and the first layer are in contact with each other.

  Conventionally, pads as connection terminals between the sensor element and the outside are provided on a support substrate. In this case, it is necessary to dispose the pad and part of the wiring connecting the pad and the sensor element outside the sealing substrate in a plan view of the support substrate. On the other hand, in this invention, the electroconductive part as a connection terminal is provided in the upper surface (opposite side with the sealing substrate) of the sealing substrate. For this reason, it is possible to omit providing a pad on the upper surface of the support substrate and outside the sealing substrate. Therefore, the supporting substrate can be reduced in size accordingly. Therefore, according to the present invention, the entire physical quantity sensor can be reduced in size.

[Application Example 2 ]
In the physical quantity sensor according to the aspect of the invention, it is preferable that the sealing substrate has a concave portion that penetrates the first layer, has the second layer or the third layer as a bottom, and stores the sensor element. .

  Thereby, when forming a recessed part by an etching, a 3rd layer functions as a stop layer at the time of etching a 1st layer. Therefore, the concave portion can be formed with high accuracy.

  After that, by removing the third layer at the bottom of the recess, a recess having the second layer as the bottom can also be formed.

[Application Example 3 ]
In the physical quantity sensor of the present invention, it is preferable that a plurality of the conductive portions are provided.

  Thereby, each conductive part can be electrically connected to the fixed electrode and the movable electrode of the sensor element, for example. Therefore, the electrostatic capacitance between the fixed electrode and the movable electrode can be detected via each conductive part.

[Application Example 4 ]
In the physical quantity sensor of the present invention, it is preferable that the sealing substrate has an insulating portion that insulates the plurality of conductive portions from each other.
Thereby, it can prevent that electrical conduction parts short-circuit.

[Application Example 5 ]
An electronic apparatus according to the present invention includes the physical quantity sensor according to the present invention.
Thereby, an electronic device with high reliability can be obtained.

[Application Example 6 ]
The moving body of the present invention includes the physical quantity sensor of the present invention.
Thereby, a mobile body with high reliability can be obtained.

It is a perspective view which shows 1st Embodiment of the physical quantity sensor 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. FIG. 4 is a partially enlarged view (enlarged sectional view) of FIG. 3. It is the BB sectional view taken on the line in FIG. It is the elements on larger scale (enlarged sectional drawing) of FIG. It is a top view (top view) of the sealing substrate shown in FIG. It is a disassembled perspective view of the sealing substrate shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the physical quantity sensor shown in FIG. 1, (a) is a figure which shows a preparation process, (b) is a figure which shows a 1st etching process, (c) is an embedding process. The figure shown, (d) is a figure which shows a 2nd etching process. It is sectional drawing for demonstrating the physical quantity sensor shown in FIG. 1, Comprising: (a) is a figure which shows a joining process, (b) is a figure which shows an arrangement | positioning process, (c) is a figure which shows a sealing process. It is sectional drawing which shows 2nd Embodiment of the physical quantity sensor of this invention. 1 is a perspective view illustrating a configuration of a mobile (or notebook) personal computer to which an electronic device including a physical quantity sensor of the present invention is applied. It is a perspective view which shows the structure of the mobile telephone (PHS is also included) to which the electronic device provided with the physical quantity sensor of this invention is applied. It is a perspective view which shows the structure of the digital still camera to which the electronic device provided with the physical quantity sensor of this invention is applied. It is a perspective view which shows the structure of the motor vehicle which applied the mobile body provided with the physical quantity sensor of this invention.

  Hereinafter, a physical quantity sensor, an electronic apparatus, and a moving body of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

First, the physical quantity sensor of the present invention will be described.
1. Physical quantity sensor <First embodiment>
FIG. 1 is a perspective view showing a first embodiment of a physical quantity sensor of the present invention. FIG. 2 is a plan view showing the physical quantity sensor shown in FIG. 3 is a cross-sectional view taken along line AA in FIG. FIG. 4 is a partially enlarged view (enlarged sectional view) of FIG. 5 is a cross-sectional view taken along line BB in FIG. 6 is a partially enlarged view (enlarged sectional view) of FIG. FIG. 7 is a plan view (top view) of the sealing substrate shown in FIG. FIG. 8 is an exploded perspective view of the sealing substrate shown in 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 and 5 to 7 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”. "

  8 to 10 exaggerate the thickness direction of the physical quantity sensor, which is greatly different from the actual dimensions.

  The physical quantity sensor 1 shown in FIGS. 1 and 7 includes a support substrate 2, an element piece 3 supported on the support substrate 2, a conductor pattern 4, and a sealing provided so as to cover the element piece 3 and the conductor pattern 4. A stop substrate 5, a sealing material 7, and three conductive portions 8 are included.

Hereinafter, each part which comprises the physical quantity sensor 1 is demonstrated in detail sequentially.
(Support substrate)
The support substrate 2 has a function of supporting the element piece 3.

  The support substrate 2 has a plate shape, and a cavity (concave portion) 21 is provided on the upper surface (one surface). The cavity portion 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 support 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 support 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 support substrate 2 in the thickness direction instead of the cavity portion 21. 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 support 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 are provided with wirings 41, 42, and 43 described later at the bottom.

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

  Further, it is preferable that the constituent material of the support 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 support 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 if the support substrate 2 and the element piece 3 are subjected to a high temperature during bonding, the residual stress between the support substrate 2 and the element piece 3 can be reduced.

The melting point or softening point (hereinafter simply referred to as “melting point”) T ₂ of the support substrate 2 is not particularly limited, but is preferably 500 ° C. or higher and 1000 ° C. or lower, for example, 600 ° C. or higher and 900 ° C. or lower. More preferably.

(Element piece)
The element piece 3 includes fixed portions 31 and 32, a movable portion 33, connecting portions 34 and 35, movable electrode portions 36 and 37, and fixed electrode portions 38 and 39.

  Such an element piece 3 has an X-axis direction (+ X) while the movable portion 33 and the movable electrode portions 36 and 37 elastically deform the connecting portions 34 and 35 according to changes in physical quantities such as acceleration and angular velocity. Direction or -X direction).

  The fixing portion 31 is bonded to a portion on the −X direction side (left side in the figure) with respect to the cavity portion 21 on the upper surface of the support substrate 2. The fixing portion 32 is bonded to the cavity portion 21 on the upper surface of the support substrate 2 at a portion on the + X direction side (right side in the drawing). 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.

  A movable portion 33 is provided between the fixed portions 31 and 32. In the present embodiment, the movable part 33 has a longitudinal shape extending in the X-axis direction. 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.

  The coupling parts 34 and 35 couple the movable part 33 to the fixed parts 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.

  The connecting portion 34 is composed of 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 a plurality of times (twice in the present embodiment) in the Y-axis direction.

  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.

  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 support 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.

  As described above, 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 (that is, the Y-axis direction).

  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 joined to the + Y direction side portion with respect to the cavity portion 21 on the upper surface of the support 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.

  Such fixed electrode fingers 382, 384, 386 and 388 and the fixed electrode fingers 381, 383, 385 and 387 are not connected to each other on the support substrate 2 and are isolated in an island shape. Thereby, the electrostatic capacitance between the fixed electrode fingers 382, 384, 386, 388 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. Can be measured separately, and based on the measurement results, the physical quantity can be detected with high accuracy.

  The fixed electrode portion 39 includes a plurality of fixed electrode fingers 391 to 398 arranged in a comb-tooth shape that meshes with the plurality of movable electrode fingers 371 to 375 of the movable electrode portion 37 described above at intervals. The end portions 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 support 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, 392, 393, 394, 395, 396, 397, 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.

  Such fixed electrode fingers 392, 394, 396, and 398 and the fixed electrode fingers 391, 393, 395, and 397 are separated from each other on the support substrate 2 like the fixed electrode portion 38 described above. Thereby, the electrostatic capacitance between the fixed electrode fingers 392, 394, 396, 398 and the movable electrode portion 37, and the electrostatic capacitance between the fixed electrode fingers 391, 393, 395, 397 and the movable electrode portion 37 Can be measured separately, and based on the measurement results, the physical quantity can be detected with high accuracy.

  Such an element piece 3 (that is, 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). ) Is formed by etching one silicon substrate described later.

  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. In this embodiment, single crystal silicon, poly A silicon material such as silicon is used.

  The silicon material constituting the element piece 3 is preferably doped with impurities such as phosphorus and boron. Thereby, the electroconductivity of the element piece 3 can be made excellent.

  Further, as described above, the element piece 3 is supported by the support substrate 2 by bonding the fixed portions 31 and 32 and the fixed electrode portions 38 and 39 to the upper surface of the support substrate 2.

  The bonding method between the element piece 3 and the support substrate 2 is not particularly limited, but an anodic bonding method is preferably used. Thereby, the element piece 3 can be firmly joined to the support substrate 2.

(Conductor pattern)
The conductor pattern 4 is provided on the upper surface (surface on the fixed electrode portions 38 and 39 side) of the support substrate 2 described above. The conductor pattern 4 includes a wiring 41, a wiring 42, and a wiring 43.

  The wiring 41 is provided outside the cavity 21 of the support substrate 2 described above, and is formed along the outer periphery of the cavity 21. The end of the wiring 41 on the −X axis side is located in the vicinity of the edge of the support substrate 2 on the −X axis side. Further, the end portion of the wiring 41 on the −X axis side is electrically connected to the sealing substrate 5 through the protrusion 411.

  Such a wiring 41 is electrically connected to the fixed electrode fingers 382, 384, 386, and 388 of the element piece 3 via conductive protrusions 481, respectively, and the fixed electrode fingers 392, 394, 396, 398 is electrically connected to each other through a conductive protrusion 482.

  The wiring 42 is provided along the outer peripheral edge inside the wiring 41 and outside the hollow portion 21 of the support substrate 2. The end of the wiring 42 on the −X axis side is located in the vicinity of the −X axis side edge of the support substrate 2 and on the −Y axis side of one end of the wiring 42. Further, the end of the wiring 41 on the −X axis side is electrically connected to the sealing substrate 5 through the protrusion 421.

  Such a wiring 42 is electrically connected to each fixed electrode finger 381, 383, 385, 387 of the element piece 3 via a conductive protrusion 471, and each fixed electrode finger 391, 393, 395, 397 are electrically connected to each other through a conductive protrusion 472.

  The wiring 43 is drawn from a joint portion with the fixed portion 31 on the support substrate 2. Further, the end of the wiring 43 on the −X axis side is located near the −X axis side edge of the support substrate 2 and on the −Y axis side from one end of the wiring 41. Further, the end portion of the wiring 41 on the −X axis side is electrically connected to the sealing substrate 5 through the protrusion 431.

The constituent materials of the wirings 41 to 43 are not particularly limited as long as they have conductivity, and various electrode materials can be used. For example, ITO (Indium Tin Oxide) and IZO (Indium Zinc Oxide) can be used. ), 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. These can be used alone or in combination of two or more.

  By providing such a conductor pattern 4 on the upper surface of the support substrate 2, the capacitance between the fixed electrode fingers 382, 384, 386 and 388 and the movable electrode portion 36 via the wiring 41 and the fixed electrode The electrostatic capacitance between the fingers 392, 394, 396, 398 and the movable electrode part 37 is measured, and the static electricity between the fixed electrode fingers 381, 383, 385, 387 and the movable electrode part 36 via the wiring 42 is measured. The capacitance and the capacitance between the fixed electrode fingers 391, 393, 395, 397 and the movable electrode portion 37 can be measured. In the present embodiment, the wiring 43 functions as a grounding wiring.

  Note that an insulating film may be provided over the wirings 41 to 43 in portions other than the protrusions 471, 472, 481, and 482.

(Sealing substrate)
As shown in FIGS. 1 and 3 to 8, the sealing substrate 5 has a function of protecting the element piece 3. The sealing substrate 5 has a plate shape, and a recess 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 sealing substrate 5 is joined to the upper surface of the support substrate 2 mentioned above.

  The sealing substrate 5 is an SOI substrate, and as shown in FIGS. 3 to 8, a conductive layer (first layer) 52 and a conductive layer (second layer) 53 having conductivity and insulating properties having insulation properties. Layer (third layer) 54. The conductive layer 52, the insulating layer 54, and the conductive layer 53 are stacked in this order from the bottom.

  The conductive layer 52 is located on the support substrate 2 side and is a portion where the recess 51 is formed. In addition, a rectangular through hole is formed in the conductive layer 52, and one of the through holes is closed by an insulating layer 54 to form a recess 51.

  The conductive layer 52 is in contact with the protrusion 411 of the wiring 41, the protrusion 421 of the wiring 42, and the protrusion 431 of the wiring 43. For this reason, the conductive layer 52 is electrically connected to the element piece 3 through the wirings 41, 42, and 43.

  The conductive layer 52 is thicker than both the conductive layer 53 and the insulating layer 54. Further, the conductive layer 52 has a thickness that can form a recess that allows vibration of the element piece 3. Specifically, the thickness of the conductive layer 52 is preferably 10 μm or more and 100 μm or less, and more preferably 30 μm or more and 80 μm or less.

  The conductive layer 53 is thicker than the insulating layer 54. The conductive layer 53 has a thickness that can sufficiently secure the length of through-holes 55a to 55d described later. Specifically, the thickness of the conductive layer 53 is preferably 5 μm or more and 50 μm or less, and more preferably 15 μm or more and 40 μm or less.

  The insulating layer 54 insulates the conductive layer 52 and the conductive layer 53. The insulating layer 54 has a thickness that can insulate the conductive layers 52 and 53. Specifically, the thickness of the insulating layer 54 is preferably 0.1 μm or more and 5 μm or less, and more preferably 0.3 μm or more and 2 μm or less.

The constituent materials of the conductive layers 52 and 54 are not particularly limited as long as they have conductivity. In this embodiment, the conductive layers 52 and 54 are, for example, silicon materials doped with impurities such as phosphorus and boron. It consists of The constituent material of the insulating layer 54 is not particularly limited as long as it has insulating properties. In this embodiment, the insulating layer 54 is made of SiO ₂ .

  The sealing substrate 5 having such a configuration is divided into four regions 5A, 5B, 5C, and 5D that form a rectangle when viewed from the Z-axis direction. The region 5A is a region including the recess 51. Each of the regions 5B to 5D is located on the −X axis side with respect to the region 5A. The regions 5B to 5D are provided in this order from the + Y axis side to the −Y axis direction.

  Further, as shown in FIGS. 7 and 8, in the conductive layers 52 and 54, the insulating portions 6 are embedded in the boundary portions of the regions 5A to 5D, respectively. The insulating portion 6 is embedded over the entire area of the conductive layers 52 and 54 in the thickness direction. Thus, the regions 5A to 5D are partitioned from each other by the insulating portion 6. Therefore, the regions 5A to 5D are in a state of being electrically separated from each other.

  As shown in FIGS. 5 to 7, a through hole 55 a that penetrates the conductive layer 53 and the insulating layer 54 is formed in the region 5 </ b> A. The through hole 55 a communicates with the recess 51.

  The through hole 55a has a circular cross section. The through hole 55 a has a transverse area that gradually decreases toward the insulating layer 54 at least in the conductive layer 53. The ratio D1 / D2 between the diameter D1 of the upper surface opening of the through hole 55a and the lower surface opening D2 of the through hole 55a is preferably 4 to 100, and more preferably 8 to 35. Thereby, as will be described later, the spherical sealing material 7a can be stably disposed in the through hole 55a.

  The diameter D1 of the upper surface opening of the through hole 55a is not particularly limited, but is preferably 200 μm or more and 500 μm or less, and more preferably 250 μm or more and 350 μm or less. On the other hand, the lower surface opening D2 of the through hole 55a is not particularly limited, but is preferably 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 30 μm or less.

  The through hole 55a is filled with a conductive sealing material 7. Thereby, the recessed part 51 is sealed. The constituent material of the sealing material 7 is not particularly limited. For example, a metal material such as an Au—Ge alloy or an Au—Sn alloy, a low melting point glass material, or the like can be used.

  A through hole (concave portion) 55b is formed in the region 5B, a through hole (concave portion) 55c is formed in the region 5C, and a through hole (concave portion) 55d is formed in the region 5D.

  The through holes 55 b to 55 d penetrate the conductive layer 53 and the insulating layer 54 and reach the conductive layer 52. Therefore, it can be said that the through-holes 55b to 55d are configured by a recess having the conductive layer 52 as a bottom. These through holes 55b to 55d are formed in the same shape and dimensions as the above-described through hole 55a.

  As shown in FIGS. 5 to 7, the through holes 55 b to 55 d are provided with conductive portions 8, respectively. Each conductive portion 8 is in contact with the conductive layer 52. As a result, the conductive portion 8 of the through hole 55b is electrically connected to the conductive layer 52 in the region 5B, and the conductive portion 8 of the through hole 55c is electrically connected to the conductive layer 52 in the region 5C. The conductive portion 8 is electrically connected to the conductive layer 52 in the region 5D. Therefore, the conductive portion 8 of the through hole 55b is electrically connected to the wiring 41, the conductive portion 8 of the through hole 55c is electrically connected to the wiring 42, and the conductive portion 8 of the through hole 55d is connected to the wiring 43. Electrically connected.

  In the through hole 55b, the conductive portion 8 is exposed to the upper side through the upper surface opening. In the through hole 55c, the conductive portion 8 is exposed to the upper side through the upper surface opening. In the through hole 55d, the conductive portion 8 is exposed to the upper side through the upper surface opening.

  Further, as described above, since the conductive portions 8 in the regions 5B to 5D are prevented from being short-circuited with each other, the three conductive portions 8 each function as a connection terminal that electrically connects the element piece 3 and the outside. To do.

  Thus, according to the present invention, the conductive portion 8 as a connection terminal can be disposed on the side opposite to the element piece 3 of the sealing substrate 5, that is, on the upper surface. As a result, the wirings 41 to 43 on the support substrate 2 are pulled out to the outside of the sealing substrate 5 and a connection terminal for electrically connecting the element piece 3 and the outside is formed at the end portion. It can be omitted. Therefore, the support substrate 2 can be made smaller (the same size as the sealing substrate 5). As a result, the physical quantity sensor 1 as a whole can be reduced in size.

  Further, by disposing the conductive portions 8 in the through holes 55b to 55d, the conductive portions serving as connection terminals on the upper surface side of the sealing substrate 5 even though the sealing substrate 5 has the insulating layer 54. Can be exposed.

  The constituent material of the conductive portion 8 is not particularly limited as long as it has conductivity. For example, a metal material such as an Au—Ge alloy or an Au—Sn alloy can be used. In addition, the conductive portion 8 may be the same as or different from the constituent material of the sealing material 7. In the case where the constituent materials of the conductive portion 8 and the sealing material 7 are the same, there is an advantage that they can be melted at the same timing in the sealing step described later.

Next, a method for manufacturing the physical quantity sensor 1 will be described.
9A and 9B are cross-sectional views for explaining a method of manufacturing the physical quantity sensor shown in FIG. 1, wherein FIG. 9A is a diagram showing a preparation process, FIG. 9B is a diagram showing a first etching process, and FIG. FIG. 4 is a diagram showing a burying process, and FIG. 4D is a diagram showing a second etching process. 10A and 10B are cross-sectional views for explaining the physical quantity sensor shown in FIG. 1, in which FIG. 10A is a diagram showing a bonding process, FIG. 10B is a diagram showing an arrangement process, and FIG. 10C is a sealing process. FIG.

  In the following, among the through holes 55a to 55d, the through holes 55a and 55c are representatively illustrated, but the through holes 55b and 55d are similarly processed.

  The manufacturing method includes [1] a preparation step, [2] a first etching step, [3] a second etching step, [4] an embedding step, [5] a bonding step, and [6] arrangement. And [7] a sealing step.

[1] Preparation Step First, a support substrate 2 (not shown) having an element piece 3 provided on the upper surface and an SOI substrate 5 ′ to be a sealing substrate 5 by processing are prepared (see FIG. 9). In addition, since the element piece 3 is formed on the support substrate 2 by a well-known method, description is abbreviate | omitted here.

[2] First Etching Step Next, as shown in FIG. 9B, a recess 51 and a groove 61 in which the insulating portion 6 is embedded are formed in the conductive layer 52 by etching. Along with this, in the conductive layer 53, a through hole 55a 'that becomes the through hole 55a, a through hole 55b' that becomes the through hole 55b, a through hole 55c 'that becomes the through hole 55c, and a through hole that becomes the through hole 55d 55d 'and a groove 62 in which the insulating portion 6 is embedded are formed.

In the above etching, for example, a portion other than the recess 51, the through holes 55a ′ to 55d ′ and the grooves 61 and 62 is formed by using a mask (not shown) such as a resist mask, a metal mask, a SiO ₂ mask, or a SiN mask. Done.

  The etching is performed until the recess 51, the through holes 55a 'to 55d', and the grooves 61 and 62 reach the insulating layer 54, respectively. That is, the recess 51, the through holes 55a 'to 55d', and the grooves 61 and 62 are formed by removing the conductive layers 52 and 53 until the insulating layer 54 is exposed.

  The etching method is not particularly limited. For example, one or two of a physical etching method such as plasma etching, reactive ion etching, beam etching, and optically assisted etching, and a chemical etching method such as wet etching are used. A combination of more than one species can be used.

  Here, the insulating layer 54 functions as an etching stop layer in this step. Thereby, the depth of the recessed part 51, the through-holes 55a-55d, and the groove | channels 61 and 62 can be made into a desired depth. Therefore, the formation accuracy (dimensional accuracy) of the recess 51, the through holes 55a to 55d and the grooves 61 and 62 can be increased.

[3] Second Etching Step Next, as shown in FIG. 9C, the insulating layer 54 at the bottom of the through holes 55a ′ to 55d ′ is removed by etching. Thereby, the through holes 55a to 55d are formed. At this time, in the case where the mask used in the first etching step is formed of the same material (SiO ₂ ) as the insulating layer 54, the removal of the insulating layer 54 can be performed in a lump in this step. Further, considering that the mask is slightly consumed in the first etching step, the thickness of the mask is set to about 1.5 to 2.0 times the thickness of the insulating layer 54, whereby the mask and the insulating layer are formed. 54 can be removed simultaneously or substantially simultaneously. Therefore, [2] the first etching step and [3] the second etching step can be performed smoothly.

The etching method in this step is not particularly limited, and examples thereof include dry etching using CHF ₃ and wet etching using a hydrofluoric acid aqueous solution.

  In this step, the insulating layer 54 at the bottom of the recess 51 may be removed to form the recess 51 having the conductive layer 53 as the bottom.

[4] Embedding Step Next, as shown in FIG. 9 (d), an insulating material such as a silicon oxide film is buried in the grooves 61 and 62 to form the insulating portion 6. Thereby, the regions 5A to 5D are electrically separated from each other. Examples of the burying method include a CVD method and a thermal oxidation method.
The sealing substrate 5 is obtained through the above steps [1] to [4].

[5] Joining Step Next, as shown in FIG. 10A, the sealing substrate 5 obtained above is joined to the support substrate 2 so that the element piece 3 is accommodated in the recess 51. The bonding method between the sealing substrate 5 and the support 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.

[6] Arrangement Step Next, as shown in FIG. 10B, a spherical sealing material 7a to be the sealing material 7 is arranged in the through hole 55a, and the conductive portion 8 and the through holes 55b to 55d are arranged. A spherical conductive portion 8a is disposed. The outer diameters (maximum outer diameters) of the sealing material 7a and the conductive portion 8a are larger than the diameters of the lower surface openings of the through holes 55a to 55d, and are larger than the diameters of the through holes 55a to 55d at the insulating layer 54. small. Accordingly, the sealing material 7a can be disposed in the through hole 55a, and the conductive portion 8 can be disposed in the through holes 55b to 55d (hereinafter, this state is referred to as “arrangement state”).

  Further, as described above, the through holes 55a to 55d are gradually reduced in the conductive layer 53 as the hole diameter goes downward. Thereby, in the arrangement | positioning state, the sealing material 7a will respectively remain in the part corresponded with the hole diameter of the through-hole 55a. Therefore, the sealing material 7a is restricted from moving in the Z-axis direction within the through hole 55a.

  Furthermore, the sealing material 7a stays at a portion that matches the hole diameter of the through hole 55a, so that the sealing material 7a can also be restricted from moving in the XY plane direction. Thereby, the sealing material 7a can be arrange | positioned more stably in the through-hole 55a.

The outer diameter of the sealing material 7a is preferably 100 μm or more and 500 μm or less, and more preferably 150 μm or more and 300 μm or less.
The same applies to the conductive portion 8a.

[7] Sealing step Next, the sealing material 7a and the conductive portion 8 are heated. In the present embodiment, the sealing material 7a and the conductive portion 8 are heated by placing the support substrate 2 and the sealing substrate 5 in a chamber (not shown) and heating the inside of the chamber after the placing step. . The temperature in the chamber is set to be equal to or higher than the melting points of the sealing material 7a and the conductive portion 8, and each sealing material 7a is melted. As a result, in the through-hole 55a, the sealing material 7a that has become liquid by melting (hereinafter, this liquid sealing material 7a is referred to as "sealing material 7b") extends to the inner surface of the through-hole 55a over the entire circumference. In close contact. Therefore, the space inside the recess 51 and the space outside the recess 51 are separated by the sealing material 7b. That is, the recess 51 is hermetically sealed.

The temperature in the chamber in this process is a temperature lower than the melting point T ₅ of the melting point T ₂ and the sealing substrate 5 of the supporting substrate 2. Thereby, the thermal deformation of the support substrate 2 and the sealing substrate 5 in this process can be prevented. Therefore, the physical quantity sensor 1 with high dimensional accuracy can be obtained.

  Here, by using a metal material as the sealing material 7, the sealing material 7 b has a relatively high surface tension and tends to stay in the through hole 55 a. Therefore, the sealing material 7b can be prevented from flowing into the recess 51 from the lower surface opening of the through hole 55a.

Further, the viscosity of the sealing material 7b is preferably high to some extent, specifically, it is preferably 1 × 10 ⁻³ Pa · s or more, and more preferably 3 × 10 ⁻³ Pa · s or more. preferable. Thereby, it can prevent more effectively that the sealing material 7b flows in into the recessed part 51 from the lower surface opening of the through-hole 55a.

  Furthermore, as described above, the opening diameter of the lower surface opening of the through hole 55a is sufficiently small. Thereby, combined with the above, it is possible to more effectively prevent the sealing material 7b from flowing into the recess 51.

  In the through holes 55b to 55d, the conductive portion 8a is melted to form a liquid conductive portion 8b. As a result, the conductive portion 8 b flows down through the through holes 55 b to 55 d and comes into contact with the conductive layer 52. Thereby, the conductive layer 52 and the conductive portion 8b are electrically connected.

  Finally, the sealing material 7b and the conductive portion 8b are solidified by returning them to room temperature, for example. Thereby, while the recessed part 51 is sealed with the sealing material 7, the physical quantity sensor 1 provided with the electroconductive part 8 as a connection terminal on the upper surface of the sealing substrate 5 can be obtained.

Prior to melting the sealing material 7a, the pressure in the chamber may be temporarily set to a vacuum or a reduced pressure, and then an inert gas may be injected into the chamber to return to atmospheric pressure. Thereby, an inert gas flows in into the recessed part 51 via the micro clearance gap between the sealing material 7a and the inner surface of the through-hole 55a. And in this state, the element piece 3 is excellent in long-term stability by sealing the recessed part 51 as mentioned above.
Thus, the physical quantity sensor 1 is obtained through steps [1] to [7].

  Moreover, according to this manufacturing method, the electroconductive part 8 as a connection terminal and the sealing material 7 which seals a recessed part can be formed simultaneously at the same process. Therefore, it is possible to omit separately performing the manufacturing process of the conductive part and the manufacturing process of the sealing part. Therefore, this manufacturing method is excellent in productivity.

  Moreover, according to this manufacturing method, since the sealing substrate 5 is manufactured using the SOI substrate as a base material, the insulating layer 54 functions as an etching stop layer. Thereby, the conductive layers 52 and 54 can be removed by etching to a desired depth. Therefore, the physical quantity sensor 1 can be obtained with high dimensional accuracy.

Second Embodiment
Next, a second embodiment of the physical quantity sensor of the present invention will be described.

FIG. 11 is a cross-sectional view showing a second embodiment of the physical quantity sensor of the present invention.
Hereinafter, the second embodiment of the physical quantity sensor will be described with reference to this drawing. However, the difference from the above-described embodiment will be mainly described, and the description of the same matters will be omitted.

  The second embodiment is substantially the same as the first embodiment except that the configuration of the sealing substrate is different.

  As illustrated in FIG. 11, in the physical quantity sensor 1 </ b> A, the sealing substrate 5 </ b> E has a two-layer structure including a conductive layer 56 and an insulating layer 57. The conductive layer 56 and the insulating layer 57 are laminated in this order from the support substrate 2 side. As a result, the insulating layer 56 is exposed on the entire upper surface, and the upper surface of the sealing substrate 5E can be prevented from being unintentionally electrically connected to the outside.

In the conductive layer 56, a recess 51 is formed as in the first embodiment.
Through holes 55 a to 55 d are formed in the insulating layer 57. Further, the insulating layer 57 serves as a part of the wall portion of the internal space in which the element piece 3 is accommodated. For this reason, the thickness of the insulating layer 57 is preferably a thickness having sufficient mechanical strength. Specifically, the thickness of the insulating layer 57 is preferably 5 μm or more and 150 μm or less, and more preferably 10 μm or more and 50 μm or less. The thickness of the conductive layer 56 is approximately the same as the thickness of the conductive layer 52 in the first embodiment.

  The material constituting the conductive layer 56 is not particularly limited as long as it has conductivity, and the same constituent material as that of the conductive layer 52 in the first embodiment can be used.

  The material constituting the insulating layer 57 is not particularly limited as long as it has insulating properties, and the same constituent materials as those of the insulating layer 54 in the first embodiment, various glass materials, various ceramic materials, and the like are used. be able to.

  Moreover, when the insulating layer 57 is comprised with the material which has a light transmittance among these materials, the element piece 3 in the recessed part 51 can be visually recognized. Therefore, it can be confirmed whether the element piece 3 is a defective product.

  According to such a physical quantity sensor 1 </ b> A, it is possible to omit forming the groove 62 of the conductive layer 53 and embedding the insulating portion 6 in the groove 62 in the first embodiment. Therefore, the manufacturing process of the physical quantity sensor 1A is simplified accordingly.

  Furthermore, the insulating layer 57 functions as a stop layer for etching when the conductive layer 56 is processed by etching. Thereby, the depth of the recessed part 51 and the groove | channel 62 can be made into a desired depth. Therefore, the formation accuracy (dimensional accuracy) of the recess 51 and the groove 62 can be increased.

2. Electronic Device Next, an electronic device to which the physical quantity sensor 1 is applied will be described in detail with reference to FIGS.

  FIG. 12 is a perspective view illustrating a configuration of a mobile (or notebook) personal computer to which an electronic device including the physical quantity sensor of the present invention is applied. In this figure, a personal computer 1100 includes a main body portion 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display portion 1108. The display unit 1106 is rotated with respect to the main body portion 1104 via a hinge structure portion. It is supported movably. Such a personal computer 1100 incorporates a physical quantity sensor 1 that functions as angular velocity detection means.

  FIG. 13 is a perspective view illustrating a configuration of a mobile phone (including PHS) to which an electronic device including the physical quantity sensor of the present invention is applied. In this figure, a cellular phone 1200 includes a plurality of operation buttons 1202, an earpiece 1204, and a mouthpiece 1206, and a display unit 1208 is disposed between the operation buttons 1202 and the earpiece 1204. Such a cellular phone 1200 incorporates a physical quantity sensor 1 that functions as angular velocity detection means.

  FIG. 14 is a perspective view showing a configuration of a digital still camera to which an electronic device including the physical quantity sensor 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 perform display based on an imaging signal from the CCD. The display unit 1310 displays a subject as an electronic image. Function as.

  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 that functions as angular velocity detection means.

  In addition to the personal computer (mobile personal computer) shown in FIG. 12, the mobile phone shown in FIG. 13, and the digital still camera shown in FIG. Inkjet printers), laptop personal computers, televisions, video cameras, video tape recorders, car navigation devices, pagers, electronic notebooks (including those with communication functions), electronic dictionaries, calculators, electronic game devices, word processors, workstations, televisions Telephone, 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 Type (e.g., vehicle, Sky machine, gauges of a ship), can be applied to a flight simulator or the like.

3. Next, a moving body to which the physical quantity sensor of the present invention is applied will be described in detail with reference to FIG.

  FIG. 15 is a perspective view showing a configuration of an automobile to which a moving body including a physical quantity sensor of the present invention is applied. The automobile 1500 has a built-in physical quantity sensor 1 that functions as an angular velocity detection means, and the physical quantity sensor 1 can detect the posture of the vehicle body 1501. A signal from the physical quantity sensor 1 is supplied to the vehicle body posture control device 1502, and the vehicle body posture control device 1502 detects the posture of the vehicle body 1501 based on the signal, and controls the stiffness of the suspension according to the detection result. The brakes of the individual wheels 1503 can be controlled. In addition, such posture control can be used by a biped robot or a radio control helicopter. As described above, the physical quantity sensor 1 is incorporated in realizing the posture control of various moving objects.

  As mentioned above, although the physical quantity sensor of the present invention has been described with respect to the illustrated embodiment, the present invention is not limited to this, and each part constituting the filling device has an arbitrary configuration that can exhibit the same function. Can be substituted. Moreover, arbitrary components may be added.

  In addition, the physical quantity sensor of the present invention may be a combination of any two or more configurations (features) of the above embodiments.

  In each of the above embodiments, one or two recesses are provided. However, the present invention is not limited to this, and three or more recesses are formed, and a sensor element is provided in each recess. You may arrange.

  Further, in each of the above embodiments, the through hole penetrates the second layer and the third layer, but the present invention is not limited to this, and penetrates the first layer, the second layer, and the third layer. May be. In this case, the conductive portion is provided in contact with the wiring on the support substrate.

  In each of the above embodiments, an insulating film may be formed on the inner surface of the through hole.

DESCRIPTION OF SYMBOLS 1 ... Physical quantity sensor 1A ... Physical quantity sensor 2 ... Support substrate 21 ... Cavity part 22 ... Concave part 23 ... Concave part 24 ... Concave part 3 ... Element piece 31 ... Fixed part 32 ... Fixed part 33 ... Movable part 34 ... connecting part 341 ... beam 342 ... beam 35 ... connecting part 351 ... beam 352 ... beam 36 ... movable electrode part 361 ... movable electrode finger 362 ... movable electrode finger 363 ... movable Electrode finger 364... Movable electrode finger 365... Movable electrode finger 37... Movable electrode portion 371... Movable electrode finger 372. 38... Fixed electrode portion 381... Fixed electrode finger 382... Fixed electrode finger 383... Fixed electrode finger 384... Fixed electrode finger 385... Fixed electrode finger 386. ... Fixed electrode finger 39 ... Fixed electrode 391... Fixed electrode finger 392... Fixed electrode finger 393... Fixed electrode finger 394... Fixed electrode finger 395... Fixed electrode finger 396. ... Conductor pattern 41 ... Wiring 411 ... Protrusion 42 ... Wiring 421 ... Protrusion 43 ... Wiring 431 ... Protrusion 471 ... Protrusion 472 ... Protrusion 481 ... Protrusion 482 ... Protrusion 5, 5E ... Sealing substrate 5 '... SOI substrate 5A ... area 5B ... area 5C ... area 5D ... area 51 ... concave portion 52 ... conductive layer 53 ... conductive layer 54 ... insulating layer 55a ... through hole 55a' ... Through-hole 55b …… Through hole 55b ′ …… Through hole 55c …… Through hole 55c ′ …… Through hole 55d …… Through hole 55d ′ …… Through hole 56 …… Conductive layer 57 …… Insulating layer 6 …… Insulating part 61... Groove 62... Groove 7... Sealing material 7a. 7b: Sealing material 8: Conductive portion 8a: Conductive portion 8b ... Conductive portion 1100 ... Personal computer 1102 ... Keyboard 1104 ... Main body 1106 ... Display unit 1108 ... Display unit 1200 ... Cellular phone 1202 ... Operation button 1204 ... Earpiece 1206 ... Mouthpiece 1208 ... Display 1300 ... Digital still camera 1302 ... Case 1304 ... Light receiving unit 1306 ... Shutter button 1308 ... Memory 1310 ... Display 1312 …… Video signal output terminal 1314 …… Input / output terminal 1430 …… TV monitor 1440 …… Personal computer 1500 …… Automobile 1501 …… Body 1502 …… Body attitude control device 1503 …… Wheel

Claims (6)

A support substrate;
A sensor element provided on the support substrate;
A first layer and a second layer having conductivity; and a third layer having an insulating property and positioned between the first layer and the second layer, and the sensor element of the support substrate. A sealing substrate that is bonded to the side surface and seals the sensor element;
A conductive portion provided on the opposite side of the surface to be bonded to the support substrate of the sealing substrate and electrically connected to the sensor element ;
The first layer, the third layer, and the second layer are laminated in this order from the support substrate side,
The sealing substrate has a through hole that penetrates the second layer and the third layer and reaches the first layer,
The conductive portion is disposed in the through hole,
The physical quantity sensor, wherein the conductive portion and the first layer are in contact with each other. 2. The physical quantity sensor according to claim 1 , wherein the sealing substrate penetrates through the first layer, has the second layer or the third layer as a bottom, and has a concave portion that houses the sensor element. The physical quantity sensor according to claim 1 , wherein a plurality of the conductive parts are provided. The physical quantity sensor according to claim 3 , wherein the sealing substrate has an insulating portion that insulates the plurality of conductive portions from each other. An electronic apparatus comprising: a physical quantity sensor according to any one of claims 1 to 4. Mobile, characterized in that it comprises a physical quantity sensor according to any one of claims 1 to 4.

Images