JP6135370B2 - Method for manufacturing functional device, electronic apparatus, and moving object - Google Patents

Description

  The present invention relates to a method for manufacturing a functional device, a functional device, an electronic apparatus, and a moving object.

2. Description of the Related Art Conventionally, as a functional device for detecting physical quantities such as acceleration and angular velocity, a physical quantity sensor having a structure in which an element part having a movable structure is provided on a base substrate and the element part is covered with a lid part having a cavity is known.
For example, in Patent Document 1, a silicon substrate as a base substrate and a glass sealing substrate as a lid are bonded together by an anodic bonding method, and an element portion formed of a vibrating body is included in a cavity included in the lid. A physical quantity sensor is disclosed as a functional device having a provided structure.

JP-A-11-142430

Such a functional device has a structure in which a glass substrate is used as a base substrate, a silicon substrate on which an element portion is formed is anodically bonded, and a lid that covers the formed element portion is anodically bonded. Devices are also being considered.
However, in the functional device having the structure described above, the base substrate generally needs to be bonded twice between the lid portion and the silicon substrate on which the element portion is formed. It is preferable to use an anodic bonding method for these bondings, but every time the number of bondings is increased, there is a problem that the movable elements (sodium ions) contained in the glass substrate as the base substrate are deficient and the bonding power is reduced. It was.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
In the functional device manufacturing method according to this application example, a first substrate having a depressed portion formed on a first surface and a second substrate are prepared, and the first surface side of the first substrate is bonded to the second substrate. A first bonding step, an exposure step of removing the substrate portion including the depressed portion of the first substrate, exposing the bonded surface of the second substrate overlapping the depressed portion in plan view, and placing the third substrate on the bonded surface And a second bonding step of bonding the second substrate and the third substrate in a state where the first substrate is positioned between the second substrate and the third substrate.

According to such a method of manufacturing a functional device, the second substrate is bonded to the first substrate in which the depressed portion is formed on the first surface in the first bonding step. In the exposure process, a part of the substrate including the depression is removed in the exposure process. Furthermore, the third substrate is bonded to the second substrate with the first substrate positioned between the second substrate and the third substrate in the second bonding step. Since the first substrate bonded to the second substrate in the first bonding step is formed with a depressed portion on the first surface to be bonded, the bonding surface of the second substrate and the portion where the depressed portion is formed There is a gap between them. Therefore, the first substrate and the second substrate are not joined at the portion where the depression is formed.
Here, the first surface of the first substrate to be bonded in the first bonding step has a portion facing the bonding region on the bonding surface of the second substrate to which the second substrate and the third substrate are bonded. A depression is formed.
Accordingly, the first substrate and the third substrate that are bonded to the bonding surface of the second substrate are not overlapped and bonded. Therefore, it is possible to bond the second substrate and the first substrate and the second substrate and the third substrate while suppressing a decrease in the bonding force of the bonding surface of the second substrate bonded to the first substrate and the third substrate. it can.

[Application Example 2]
In the functional device manufacturing method according to this application example, a second substrate having a depressed portion formed on a first surface and a first substrate are prepared, and the first substrate is bonded to the first surface of the second substrate. Removing the substrate portion of the first substrate that overlaps the depressed portion of the second substrate in plan view, exposing the depressed portion, and placing the third substrate on the depressed portion, And a second bonding step of bonding the second substrate and the third substrate with the first substrate positioned between the first substrate and the third substrate.

According to such a method for manufacturing a functional device, the first substrate is bonded to the second substrate in which the depressed portion is formed on the first surface in the first bonding step. The first substrate is partially removed from the overlapping portion of the second substrate in the exposure process. Furthermore, the third substrate is bonded to the second substrate with the first substrate positioned between the second substrate and the third substrate in the second bonding step.
Since the second substrate bonded to the first substrate in the first bonding step forms a depression on the first surface to be bonded, the bonding surface of the first substrate and the portion where the depression is formed There is a gap between them. Therefore, the first substrate and the second substrate are not joined at the portion where the depression is formed. Here, on the first surface of the second substrate to be bonded in the first bonding step, the above-described depression is formed in a portion that becomes a bonding region where the second substrate and the third substrate are bonded. Accordingly, the first substrate and the third substrate that are bonded to the second substrate are not overlapped and bonded. Therefore, it is possible to bond the second substrate and the first substrate and the second substrate and the third substrate while suppressing a decrease in the bonding force of the bonding surface of the second substrate bonded to the first substrate and the third substrate. it can.

[Application Example 3]
In the functional device manufacturing method according to the application example, it is preferable that the first bonding step and the second bonding step are bonded using anodic bonding.

  According to such a method of manufacturing a functional device, by using anodic bonding, the first substrate and the second substrate are bonded in the first bonding step, and the second substrate and the third substrate in the second bonding step. Can be firmly bonded by intermolecular bonding.

[Application Example 4]
It is preferable that the manufacturing method of the functional device according to the application example includes an element part forming step of forming the functional device by processing the first substrate after the first bonding step.

  According to such a method of manufacturing a functional device, the first substrate is formed by including an element part forming step of forming the functional device by processing the first substrate after being bonded to the second substrate by the first bonding step. It is possible to prevent the functional device from being damaged when joining. In addition, since the functional device is formed in a state where the first substrate is bonded to the second substrate, the functional device having fine circuit elements can be formed in the element portion forming step.

[Application Example 5]
In the functional device manufacturing method according to the application example, it is preferable that the bonding region of the third substrate in the second substrate is covered with a protective film prior to the element portion forming step.

  According to such a method for manufacturing a functional device, the protective film covering the bonding region of the third substrate in the second substrate is formed prior to the element portion forming step. By forming the protective film, the bonding region bonded to the third substrate can be protected from damage due to the element portion forming step. Therefore, the bonding force between the second substrate and the third substrate bonded in the second bonding step can be increased.

[Application Example 6]
A functional device according to this application example includes a functional element, a base substrate on which the functional element is mounted, and a lid member that is disposed on the functional element and bonded onto the base substrate. A depression is provided on the joint surface with the lid member, and the lid member is joined on the surface of the depression.

According to such a functional device, the functional element is mounted on the base substrate, disposed on the functional element, and the lid member is bonded to the base substrate.
The base substrate bonded to the functional element has a depressed portion on the bonded surface to be bonded. The lid member to be joined to the base substrate is joined to the surface of the depressed portion. Here, since the functional element and the lid member that are bonded to the base substrate are not overlapped and bonded, it is possible to suppress a decrease in bonding force between the base substrate and the base substrate. Further, since the depressed portion is provided in the base substrate, the lid member plate can be bonded without requiring adjustment of the bonding position with high accuracy. Therefore, it is possible to obtain a highly reliable functional device with increased bonding force between the substrates.

[Application Example 7]
The electronic apparatus according to this application example includes a functional device manufactured by any one of the above-described functional device manufacturing methods.

  According to such an electronic device, a decrease in the bonding force between the second substrate, the first substrate, and the third substrate is suppressed, and the functional device with improved reliability is mounted, so that the mounted electronic device Reliability can be increased.

[Application Example 8]
The moving body according to this application example includes a functional device manufactured by any one of the above-described functional device manufacturing methods.

  According to such a movable body, a decrease in the bonding force between the second substrate, the first substrate, and the third substrate is suppressed, and the functional device with improved reliability is mounted. Can improve the reliability.

The top view which shows typically the functional device which concerns on 1st Embodiment. Sectional drawing which shows the functional device which concerns on 1st Embodiment typically. Explanatory drawing explaining the manufacturing process of the functional device which concerns on 1st Embodiment. Explanatory drawing explaining the manufacturing process of the functional device which concerns on 1st Embodiment. Sectional drawing which shows the functional device which concerns on 2nd Embodiment typically. Explanatory drawing explaining the manufacturing process of the functional device which concerns on 2nd Embodiment. Explanatory drawing explaining the manufacturing process of the functional device which concerns on 2nd Embodiment. Explanatory drawing explaining the manufacturing process of the functional device which concerns on 3rd Embodiment. Explanatory drawing explaining the manufacturing process of the functional device which concerns on 3rd Embodiment. FIG. 3 is a diagram schematically showing a personal computer as an electronic apparatus according to an example. FIG. 3 is a diagram schematically illustrating a mobile phone as an electronic apparatus according to an example. The figure which shows typically the digital still camera as an electronic device which concerns on an Example. The figure which shows typically the motor vehicle as a moving body which concerns on an Example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure shown below, the size and ratio of each component may be described differently from the actual component in order to make each component large enough to be recognized on the drawing. is there.

[First Embodiment]
The functional device according to the first embodiment will be described with reference to FIGS.
FIG. 1 is a plan view schematically showing the functional device according to the first embodiment. FIG. 2 is a cross-sectional view schematically showing a cross section of the functional device at a portion indicated by a line segment AA ′ in FIG. 1. FIG. 3 and FIG. 4 are explanatory views for explaining the manufacturing process of the functional device according to the first embodiment.
For convenience of explanation, the lid is not shown in FIG. In FIGS. 1 and 2, the X axis, the Y axis, and the Z axis are illustrated as three axes orthogonal to each other. Note that the Z axis is an axis indicating the thickness direction in which the substrate and the lid overlap.

[Structure of functional device 1]
The functional device 1 of the present embodiment is formed by processing the element portion 3 as a functional element formed by processing the first substrate, the base substrate 2 as the second substrate, and the third substrate. And a lid portion 5 as a lid member.
As shown in FIGS. 1 and 2, the functional device 1 is provided with a base substrate 2, an element portion 3, and a wiring portion 4 on the base substrate 2. Further, the functional device 1 is provided with a lid portion 5 that covers the element portion 3.

In the functional device 1, the element portion 3 is not particularly limited and can be provided as various active elements or passive elements.
In the functional device 1 of the present embodiment, an example in which an active element is used as an example of the element unit 3 will be described.
The functional device 1 can be used as an inertial sensor, for example. Specifically, it can be used as a physical quantity sensor that detects physical quantities such as acceleration and angular velocity.

[Base substrate 2]
The base substrate 2 is a base material on which the element unit 3 and the wiring unit 4 are provided. The base substrate 2 has a plate shape, and an element portion 3, a wiring portion 4 and the like are provided on the bonding surface 2a.
Further, a groove portion 24 is provided along the wiring portion 4 on the bonding surface 2 a of the base substrate 2.

A cavity 21 is provided in the bonding surface 2 a of the base substrate 2. The hollow portion 21 has a movable weight 33, movable electrode portions 36 and 37, and beam portions 34 and 35 constituting an element portion 3 to be described later when the base substrate 2 is viewed in a plan view from a direction perpendicular to the bonding surface 2a. It is provided so as to contain. The cavity 21 has an inner bottom 21a. Such a cavity portion 21 constitutes a space that suppresses the movable weight 33, the movable electrode portions 36 and 37, and the beam portions 34 and 35 from contacting the base substrate 2, in other words, an escape portion. Thereby, the displacement of the movable weight 33 of the element part 3 can be permitted.
Note that this space may be provided as an opening that penetrates the base substrate 2 in the thickness direction (Z-axis direction) instead of the hollow portion 21 (concave portion). Further, in the present embodiment, the shape of the cavity portion 21 when viewed from above in a direction perpendicular to the bonding surface 2a is a rectangle, but is not limited thereto.

As a material constituting the base substrate 2, an insulating material is preferably used. For example, when a silicon substrate is used as the first substrate as the element unit 3, it is more preferable that the base substrate 2 is made of borosilicate glass.
For example, when borosilicate glass is used as the material constituting the base substrate 2, the functional device 1 can bond the base substrate 2 and the element portion 3 using a silicon substrate by an anodic bonding method. .

  The base substrate 2 is preferably made of a material that can minimize the difference in linear expansion coefficient from the material constituting the element unit 3. For example, by using a borosilicate glass for the base substrate 2 and a silicon substrate for the element portion 3, the difference in linear expansion coefficient between the base substrate 2 and the element portion 3 is reduced, and the base substrate 2 caused by distortion due to thermal expansion Damage to the joint portion with the element portion 3 can be suppressed.

(Element part 3)
The element portion 3 includes fixed portions 31 and 32, a movable weight 33, beam portions 34 and 35, movable electrode portions 36 and 37, and fixed electrode portions 38 and 39.
The element unit 3 has a direction of an arrow a shown in FIG. 1 while the movable weight 33 and the movable electrode units 36 and 37 elastically deform the beam units 34 and 35 according to changes in physical quantities such as acceleration and angular velocity. That is, it is displaced in the X-axis direction (+ X-axis direction or -X-axis direction).

In the element portion 3, the gap between the movable electrode portion 36 and the fixed electrode portion 38 and the gap between the movable electrode portion 37 and the fixed electrode portion 39 change with the displacement described above. In the element unit 3, the magnitudes of the capacitances between the movable electrode unit 36 and the fixed electrode unit 38 and between the movable electrode unit 37 and the fixed electrode unit 39 change with the change in the gap described above. To do.
The functional device 1 can detect physical quantities such as acceleration and angular velocity based on these changes in capacitance.

The element portion 3 is formed by integrally forming fixed portions 31 and 32, a movable weight 33, beam portions 34 and 35, and movable electrode portions 36 and 37.
As shown in FIGS. 1 and 2, the fixing portions 31 and 32 are respectively connected to the joint surface 2 a of the base substrate 2 described above. Specifically, the fixing portion 31 is connected to a portion on the −X axis direction side with respect to the cavity portion 21. The fixed portion 32 is connected to a portion on the + X axis direction side with respect to the cavity portion 21 of the bonding surface 2 a of the base substrate 2. In addition, the fixing portions 31 and 32 are provided so as to straddle the outer peripheral edge 21c of the cavity portion 21 when viewed in a plan view from a direction perpendicular to the bonding surface 2a.

  The positions, shapes, etc. of the fixing portions 31, 32 are determined according to the positions, shapes, etc. of the beam portions 34, 35, the wiring portion 4, etc., and are not limited to those described above.

(Movable weight 33)
The movable weight 33 is provided between the two fixed portions 31 and 32. In the present embodiment, the movable weight 33 has a longitudinal shape extending in the X-axis direction. The shape of the movable weight 33 is determined according to the shape, size, etc. of each part constituting the element unit 3 and is not limited to the above-described one.

The movable weight 33 is connected to the fixed portion 31 via the beam portion 34 and is connected to the fixed portion 32 via the beam portion 35. More specifically, the end portion of the movable weight 33 on the −X axis direction side is coupled to the fixed portion 31 via the beam portion 34, and the + X axis direction end portion of the movable weight 33 is interposed via the beam portion 35. Connected to the fixed portion 32.
The beam portions 34 and 35 are connected to the fixed portions 31 and 32 so that the movable weight 33 can move.

The beam portion 34 includes a plurality of 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. The beam portion 35 is composed of a plurality of beams 351 and 352 having a shape extending in the X-axis direction while meandering in the Y-axis direction, like the beam portion 34.
In the present embodiment, the beam portions 34 and 35 are configured such that the movable weight 33 can be displaced (movable) mainly in the + X axis direction and the −X axis direction indicated by the arrow a in FIG.

(Movable electrode portions 36 and 37)
The movable electrode portion 36 extends from the movable weight 33 in the Y-axis direction that intersects the X-axis direction (both directions of arrow a shown in FIG. 2) in which the movable weight 33 changes. A plurality of movable electrode portions 36 are provided side by side so as to protrude from the movable weight 33 in the + Y-axis direction and form a comb shape.
The movable electrode portion 37 extends from the movable weight 33 in the −Y-axis direction that intersects with the X-axis direction (both directions of arrow a shown in FIG. 2) in which the movable weight 33 changes. The movable electrode part 37 protrudes from the movable weight 33 in the −Y-axis direction, and a plurality of movable electrode parts 37 are provided side by side so as to form a comb shape.

  In this way, the plurality of movable electrode portions 36 and the plurality of movable electrode portions 37 are provided side by side in the X-axis direction (the direction of arrow a shown in FIG. 1) in which the movable weight 33 is movable. In other words, the plurality of movable electrode portions 36 and 37 are provided so as to be aligned along the X-axis direction, which is the direction in which the movable weight 33 is displaced, and to extend on both sides in the Y-axis direction intersecting the displacing direction. ing. Thereby, according to the displacement of the movable weight 33, the electrostatic capacitance which arises between the fixed electrode parts 38 and 39 mentioned later and the movable electrode parts 36 and 37 can be changed.

(Fixed electrode portions 38, 39)
The fixed electrode portion 38 has a gap with respect to the movable electrode portion 36 described above, and is provided so as to form a comb tooth shape.
The fixed electrode portion 38 includes a fixed electrode 381 as a first fixed electrode portion and a fixed electrode 382 as a second fixed electrode. The fixed electrodes 381 and 382 are provided with a gap from the movable electrode portion 36, respectively. In addition, when describing with the fixed electrode part 38, it demonstrates as what includes the fixed electrodes 381 and 382.
The fixed electrode portion 39 has a gap with respect to the movable electrode portion 37 and is formed in a meshed comb shape, like the above-described fixed electrode portion 38. The fixed electrode portion 39 includes a fixed electrode 391 as a third fixed electrode portion and a fixed electrode 392 as a fourth fixed electrode. The fixed electrodes 391 and 392 are provided with a gap from the movable electrode portion 37, respectively. In addition, when describing with the fixed electrode part 39, it demonstrates as what includes the fixed electrodes 391 and 392.

  The fixed electrode portion 38 is connected to the wiring portion 4 whose end opposite to the movable weight 33 is extended on the bonding surface 2a. The fixed electrode portion 38 extends in the −Y-axis direction where the movable weight 33 is provided with one end on the side connected to the wiring portion 4 as a fixed end and the opposite side as a free end.

  The fixed electrode portion 39 is connected to the wiring portion 4 whose end opposite to the movable weight 33 is extended on the bonding surface 2a. The fixed electrode portion 39 is extended in the + Y-axis direction where the movable weight 33 is provided with one end on the side connected to the wiring portion 4 as a fixed end and the opposite side as a free end.

(Wiring part 4)
The wiring part 4 is composed of wirings 41, 42, 43 and pad electrodes 44, 45, 46. The wiring part 4 is disposed in a groove part 24 provided on the bonding surface 2 a of the base substrate 2.
One end of each of the wirings 41, 42, and 43 extends toward the fixed portion 31 and the fixed electrode portions 38 and 39, and the other end is connected to the pad electrodes 44, 45, and 46.

The wiring 41 is provided on the bonding surface 2 a of the base substrate 2 and between the outer peripheral edge 2 c of the base substrate 2 and the outer peripheral edge 21 c of the cavity portion 21. Further, a groove 24a is provided along the wiring 41, and the wiring 41 is disposed on the inner bottom surface of the groove 24a.
The wiring 41 is electrically connected to the fixed electrode 381 as the first fixed electrode and the fixed electrode 391 as the third fixed electrode among the plurality of fixed electrode portions 38 and 39. In addition, the wiring part 4 is connected to the pad electrode 44 on the bonding surface 2 a of the base substrate 2 at the other end that is different from the one connected to the fixed electrode parts 38 and 39.

The wiring 42 is provided on the bonding surface 2 a of the base substrate 2 and between the outer peripheral edge 2 c of the base substrate 2 and the outer peripheral edge 21 c of the cavity portion 21. A groove 24b is provided along the wiring 42, and the wiring 42 is disposed on the inner bottom surface of the groove 24b.
The wiring 42 is electrically connected to the fixed electrode 382 as the second fixed electrode and the fixed electrode 392 as the fourth fixed electrode among the plurality of fixed electrode portions 38 and 39. Further, the wiring 42 is connected to the pad electrode 45 on the bonding surface 2 a of the base substrate 2 at the other end different from the one connected to the fixed electrode portions 38 and 39.

  The wiring 43 is provided on the bonding surface 2 a from the fixing portion 31 on the base substrate 2 toward the outer peripheral edge 2 c of the base substrate 2. A groove 24c is provided along the wiring 43, and the wiring 43 is disposed on the inner bottom surface of the groove 24c. The other end of the wiring 43 that is different from the one end connected to the fixing portion 31 is connected to the pad electrode 46 on the bonding surface 2 a of the base substrate 2.

  The material constituting the wiring part 4 is not particularly limited as long as it has conductivity. For example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), Gold (Au), Platinum (Pt), Silver (Ag), Copper (Cu), Aluminum (Al), Titanium (Ti), Tungsten (W) , Chromium (Cr), or an alloy containing these, and one or a combination of these can be used.

(Cover 5)
The lid 5 is provided to protect the element unit 3 described above. The lid 5 is bonded to the bonding surface 2 a of the base substrate 2.
The lid portion 5 is provided with a cavity 52 as a space portion having a concave shape on the surface facing the base substrate 2.

  The cavity 52 is provided so as to contain the element portion 3. Specifically, the movable weight 33 and the movable electrode portions 36 and 37 are provided so as to allow displacement. The depth of the cavity 52 in the direction perpendicular to the bonding surface 2a is larger (deeper) than the thickness of the element portion 3 in the direction. Thereby, the element part 3 can be allowed to move.

The lid 5 is connected to the bonding surface 2a of the base substrate 2 described above, and an anodic bonding (connection) method can be used as the connection method.
As a material constituting the lid portion 5, a material that can be easily processed into a concave shape to be the cavity 52 is suitable. Further, as a material constituting the lid portion 5, it is preferable to use a silicon substrate in the present embodiment in which an anodic bonding method is used for joining the lid portion 5 and the base substrate 2.

[Method for Manufacturing Functional Device 1]
Next, a method for manufacturing the functional device 1 will be described.
3 and 4 are cross-sectional views illustrating the manufacturing process of the functional device 1, and schematically show a cross section of the functional device 1 along the line AA ′ shown in FIG.

The manufacturing method of the functional device 1 includes a base substrate preparation step, a base substrate processing step, and a wiring portion forming step. In addition, the manufacturing method of the functional device 1 includes a first bonding step for bonding the element substrate 103 as the first substrate and the base substrate 2 as the second substrate, and an element for forming the element portion 3 on the element substrate 103. A part forming step, an exposing step of removing a part of the element substrate 103, and a second bonding step of bonding the base substrate 2 and the lid portion 5 as the third substrate.
Here, the description will be made on the assumption that a single functional device 1 is formed, but a plurality of functional devices 1 may be arranged in parallel.

[Base substrate preparation process]
FIG. 3A shows a state in which the base substrate 2 on which the element portion 3 and the wiring portion 4 are formed is prepared.
The base substrate preparation step is a step of preparing the base substrate 2 on which the element portion 3 and the wiring portion 4 are formed and to which the lid portion 5 is bonded.

[Base substrate processing process]
FIG. 3B shows a state where the cavity 21 and the groove 24 are formed on the bonding surface 2 a of the base substrate 2.
The base substrate processing step is a step of forming the cavity portion 21 and the groove portion 24 on the bonding surface 2a.
The cavity portion 21 and the groove portion 24 can be formed by forming a mask pattern (not shown) having an opening in a portion where these are formed on the bonding surface 2a and etching the base substrate 2 by a wet etching method. . In the base substrate processing step, the wet etching method is used as a method of forming the cavity 21 and the groove 24 in the base substrate 2, but the dry etching method may be used without being limited thereto.

[Wiring section forming process]
FIG. 3C shows a state in which the wiring part 4 is formed on the bonding surface 2 a of the base substrate 2.
The wiring portion forming step is a step of forming the wiring portion 4 (wirings 41, 42, 43) along the groove portions 24 (24a, 24b, 24c) formed on the bonding surface 2a shown in FIG. is there.
The wiring portion 4 is formed by forming a mask pattern (not shown) opened along the groove portion 24 where the wiring portion 4 is formed on the bonding surface 2a, and depositing a conductive material on the bonding surface 2a by sputtering. Can be formed. In the wiring portion forming step, a sputtering method is used as a method of forming the wiring portion 4 on the bonding surface 2a. However, the method is not limited to this, and the conductive material is bonded to the bonding surface by a CVD (chemical vapor deposition) method. It may be deposited on 2a and patterned by patterning the wiring portion 4 using a photolithography method.

[First joining step]
The first bonding step is a step of bonding the element substrate 103 to be the element portion 3 shown in FIG. 3D to the bonding surface 2 a of the base substrate 2.
The first bonding step is a step of bonding the element substrate 103, which is a material for forming the element portion 3 in the element portion forming step described later, on the bonding surface 2a by an anodic bonding method.
Here, as the element substrate 103 of the present embodiment, a substrate on which the depression 113 is formed in advance is used. The depressed portion 113 is provided on the element substrate 103 so as to cover the bonding region 56a on the bonding surface 2a to which the base substrate 2 and the lid portion 5 are bonded by a second bonding step described later. Here, the bonding region 56 a is a portion where the base substrate 2 and the lid portion 5 are bonded, and is a virtual region on the bonding surface 2 a of the base substrate 2.
Further, in the first bonding step, the base substrate 2 and the element substrate 103 are bonded so that the depressed portion 113 covers at least a part of the bonding region 56a when viewed in a plan view from a direction perpendicular to the bonding surface 2a. .
The depression 113 is formed on the element substrate 103 by, for example, forming a mask pattern in which a portion where the depression 113 is formed is formed on the surface bonded to the base substrate 2 and forming the depression 113 by photolithography. Can do.

  In the first bonding step, the base substrate 2 and the element substrate 103 are bonded by an anodic bonding method, and the base substrate 2 using a borosilicate glass containing an alkali metal element (movable element) such as sodium has conductivity. The element substrate 103 using silicon is placed in an inert gas atmosphere (nitrogen or argon) at a high temperature (approximately 300 ° C. to 500 ° C.) or in a vacuum. Further, a high voltage (approximately 400 V to 800 V) is applied between the base substrate 2 and the element substrate 103. As a result, the base substrate 2 and the element substrate 103 are covalently bonded by electrostatic attraction on the bonding surface 2a to be bonded, and are firmly bonded to each other.

More specifically, the base substrate 2 (borosilicate glass) contains an alkali metal element (movable element) such as sodium (Na), and these movable elements (Na ions) are contained in the base substrate 2 (borosilicate glass). ) Can exercise freely. On the other hand, if there is an element defect (missing) in any of SiO ₂ constituting the base substrate 2 (borosilicate glass), it has a charge of SiO 2 ⁻ and is electrically neutral while paired with a movable element. .
When the base substrate 2 having such characteristics is exposed to a high temperature and a negative voltage is applied to the base substrate 2 through the electrode under conditions that allow the movable element to move, the movable element moves to the side where the electrode is provided. In the junction region 56a is a joint surface between the base substrate 2 and the element substrate 103 composed of silicon, SiO the base substrate 2 side (joint surfaces 2a) ^- (a layer Na ions deficient) depletion, the element substrate 103 A layer in which positive charges are collected is formed on the first surface 103a on the side. As a result, an electrostatic attractive force is generated at the interface between the bonding surface 2a of the base substrate 2 and the first surface 103a of the element substrate 103, whereby a covalent bond is generated, and the base substrate 2 and the element substrate 103 are bonded. The

By the way, as described above, a state in which the movable element is deficient occurs at the interface between the bonded surface 2a and the first surface 103a. Therefore, when anodic bonding is performed again on the same bonding surface 2a, there is a possibility that the bonding force is reduced because the movable elements contained in the vicinity of the bonding surface 2a of the base substrate 2 are deficient.
Therefore, in the method for manufacturing the functional device 1 according to the present embodiment, the bonding region 56a on the bonding surface 2a where the base substrate 2 and the lid 5 are bonded in the second bonding process is used as the element substrate 103 in the first bonding process. A depression 113 is provided in the element substrate 103 so as not to be bonded. In the first bonding step, the base substrate 2 and the element substrate 103 provided with the depressed portion 113 are bonded to each other, so that deficiency of Na ions in the bonding region 56a on the bonding surface 2a can be suppressed.
Therefore, when the base substrate 2 and the lid portion 5 are joined in the second joining step described later, Na ions can be moved in the joining region 56a to which they are joined, and the base substrate 2 and the base substrate 2 are joined in the joining region 56a. The lid 5 is covalently bonded by electrostatic attraction and can be firmly bonded.

[Element part formation process / exposure process]
In the element portion forming step, the element substrate 103 is processed, and the fixed portions 31 and 32, the movable weight 33, the beam portions 34 and 35, the movable electrode portions 36 and 37, and the fixed electrode portions 38 and 39 constituting the element portion 3 are formed. It is a process of forming.
The exposure process is a process of removing a part including the depressed portion 113 of the element substrate 103 bonded to the base substrate 2.

FIG. 3E shows a state in which the element substrate 103 is thinned to a thickness necessary for forming the element portion 3.
The element part forming step includes a step of thinning the element substrate 103 shown in FIG.
The element substrate 103 can be thinned by, for example, a CMP (Chemical Mechanical Polishing) method. In the element portion forming step, the CMP method is used as a method for thinning the element substrate 103, but the present invention is not limited to this, and a lapping method or the like may be used. Note that the step of thinning the element substrate 103 may be performed as appropriate depending on the thickness of the element substrate 103 and the thickness of the element portion 3, and is not an essential step.

FIG. 4F shows a state where the element portion 3 is formed. In addition, a part of the element substrate 103 including the depression 113 is removed.
In the element part forming step, the element part 3 is formed by patterning the thinned element substrate 103 as shown in FIG. In the exposure step, patterning for removing a part of the element substrate 103 including the depressed portion 113 is performed simultaneously with the element portion forming step, thereby exposing the bonding region 56a to which the lid portion 5 is bonded.
The element portion 3 is formed by patterning the fixed portions 31 and 32, the movable weight 33, the beam portions 34 and 35, the movable electrode portions 36 and 37, and the fixed electrode portions 38 and 39 on the element substrate 103, for example, dry etching. It can be done using the law. In the element part forming step, the dry etching method is used to form the element part 3, but the element part 3 is not limited to this, and the element part 3 may be formed by patterning using a wet etching method or the like. good.
In the exposure process, the element substrate 103 is removed from the unnecessary part as the element part 3 simultaneously with the formation of the element part 3 in the element part forming process. By removing the element substrate 103, the previously formed depression 113 is also removed. As a result, the bonding region 56a facing the depressed portion 113 that has not been bonded to the element substrate 103 is exposed, and the lid 5 is bonded in a second bonding process described later.

[Second joining step]
FIG. 4G shows a state where the lid 5 is bonded to the base substrate 2.
The second joining step is a step of joining the lid portion 5 having the cavity 52 to the joining surface 2a.
Here, the lid 5 of the present embodiment has a cavity 52 formed in advance. The cavity 52 can be formed on the lid 5 by forming a mask pattern in which a portion where the cavity 52 is to be formed is formed on the surface 5a to be bonded to the base substrate 2, and by photolithography.

In the second bonding step, the top surface 54a of the lid portion 5 provided with the cavity 52 and the bonding region 56a on the bonding surface 2a overlap when viewed in a plan view from the direction perpendicular to the bonding surface 2a. The base substrate 2 and the lid portion 5 are joined.
In the second bonding step, the base substrate 2 and the lid 5 are bonded using an anodic bonding method. The base substrate 2 and the lid 5 are joined by the anodic bonding method, similarly to the anodic joining of the base substrate 2 and the element substrate 103 in the first joining step, the lid 5 made of the base substrate 2 and the silicon substrate. Are placed in a high-temperature inert gas atmosphere or in a vacuum. Furthermore, anodic bonding between the base substrate 2 and the lid portion 5 is performed by applying a high voltage between the base substrate 2 and the lid portion 5 so that a covalent bond is formed on the bonding region 56a.

In the second bonding step, since the bonding region 56a on the bonding surface 2a of the base substrate 2 is not in contact (bonding) with the element substrate 103 in the first bonding step described above, the lack of Na ions in the bonding region 56a. Has not occurred.
Therefore, when the base substrate 2 and the lid portion 5 are joined in the second joining step, Na ions can be moved in the joining region 56a where they are joined, and the base substrate 2 and the lid portion 5 are joined in the joining region 56a. Thus, a covalent bond is generated by electrostatic attraction, and strong bonding can be achieved.

According to the first embodiment described above, the following effects can be obtained.
According to such a manufacturing method of the functional device 1, the base substrate 2 is bonded to the element substrate 103 in the first bonding step, and is bonded to the lid portion 5 in the second bonding step.
In the element substrate 103 to be bonded to the base substrate 2 in the first bonding step, the depressed portion 113 is formed on the first surface 103a to be bonded. Therefore, the bonded surface 2a of the base substrate 2 and the depressed portion 113 are formed. There is a gap between the element substrate 103 formed. Therefore, the base substrate 2 and the element substrate 103 are not joined at the portion where the depressed portion 113 is formed.
The lid 5 having the cavity 52 to be joined in the second joining process is joined to the base substrate 2 so that the element part 3 formed by the element part forming process is included in the cavity 52.
Here, in the first surface 103a of the element substrate 103 to be bonded in the first bonding step, a depressed portion 113 is formed at a portion facing the bonding region 56a where the base substrate 2 and the lid portion 5 are bonded. .
Thereby, the lid 5 and the element substrate 103 bonded to the bonding surface 2a of the base substrate 2 are not bonded redundantly. Further, deficiency of Na ions included in the base substrate 2 bonded to the lid 5 and the element substrate 103 is suppressed.
Therefore, in such a method for manufacturing the functional device 1, even when the base substrate 2 and the element substrate 103, and the base substrate 2 and the lid portion 5 are joined in a plurality of steps, a decrease in joining force is suppressed. It can be firmly bonded by an anodic bonding method. Further, such a manufacturing method of the functional device 1 is firmly bonded by forming the depressed portion 113 in a part of the element substrate 103 facing the bonding region 56a where the base substrate 2 and the lid 5 are bonded. The Further, by forming the depressed portion 113 in the element substrate 103 facing the bonding region 56a where the base substrate 2 and the lid portion 5 are bonded to each other, it is possible to more firmly bond the air tightly in the cavity 52 of the lid portion 5. The functional device 1 that can suppress the oxidation (deterioration) of the included element part 3 can be manufactured. In addition, it is possible to obtain the functional device 1 that increases the bonding force between the substrates and suppresses the deterioration of the element unit 3.

[Second Embodiment]
A functional device according to the second embodiment will be described with reference to FIGS.
FIG. 5 is a cross-sectional view schematically showing a functional device according to the second embodiment. FIG. 5 schematically shows a cross section of a functional device equivalent to the portion indicated by line segment AA ′ in FIG. 1. FIG. 6 and FIG. 7 are explanatory diagrams for explaining the manufacturing process of the functional device according to the second embodiment. In FIG. 5, an X axis, a Y axis, and a Z axis are illustrated as three axes orthogonal to each other, and the Z axis is an axis that indicates a thickness direction in which the substrate and the lid portion overlap each other.

The functional device 1 a according to the second embodiment is bonded to the first surface of the base substrate 2 in the bonding region 56 a where the base substrate 2 and the lid 5 are connected to the functional device 1 described in the first embodiment. The difference is that a depression 26 is provided on the surface 2a. That is, the inner bottom surface (surface) of the depressed portion 26 becomes the bonding region 56a.
Since other configurations are substantially the same as those of the functional device 1 described in the first embodiment, the same reference numerals and numerals are given to the same configurations, and description thereof is partially omitted, and the functional device 1a will be described. .

[Structure of Functional Device 1a]
The functional device 1a of the present embodiment can be used as a physical quantity sensor that detects physical quantities such as acceleration and angular velocity, similarly to the functional device 1 described in the first embodiment.
As shown in FIG. 5, the functional device 1 a includes a base substrate 2, an element unit 3, and a wiring unit 4 on the base substrate 2. The functional device 1 a is provided with a lid 5 that covers the element unit 3.

(Base substrate 2)
In the functional device 1 a, a depression 26 is provided on the bonding surface 2 a of the base substrate 2. The depression 26 is provided so as to overlap with a bonding region 56a where the base substrate 2 and the lid 5 are bonded when viewed in a plan view from a direction perpendicular to the bonding surface 2a. The depressed portion 26 has a bottomed groove shape, and is provided along a joining region 56a where the base substrate 2 and the lid portion 5 are joined. That is, the inner bottom surface of the depressed portion 26 becomes the bonding region 56a.

  Since the configuration of the other functional device 1a is the same as that of the functional device 1 described in the first embodiment, the description thereof is omitted.

[Method of Manufacturing Functional Device 1a]
A method for manufacturing the functional device 1a will be described.
6 and 7 are cross-sectional views illustrating the manufacturing process of the functional device 1a, and schematically show the same cross section as the functional device 1 along the line AA ′ shown in FIG.

  Similar to the functional device 1 described in the first embodiment, the method for manufacturing the functional device 1a according to the present embodiment includes a substrate preparation step, a base substrate processing step, and a wiring portion forming step. In addition, the manufacturing method of the functional device 1a includes a first bonding step of bonding the element substrate 103 as the first substrate and the base substrate 2 as the second substrate, and element portion formation for forming the element portion 3 on the element substrate 103. A step, an exposure step of removing a part of the element substrate 103, and a second bonding step of bonding the base substrate 2 and the lid portion 5 as the third substrate.

The manufacturing method of the functional device 1a of the present embodiment is different from the manufacturing method of the functional device 1 described in the first embodiment in that a depressed portion 26 is formed on the bonding surface 2a of the base substrate 2 in the base substrate processing step. Is different. Other configurations and the like are substantially the same as those of the functional device 1 described in the first embodiment. Therefore, the same configurations are denoted by the same reference numerals and reference numerals, and description thereof is partially omitted.
In addition, although it demonstrates on the assumption that the single functional device 1a is formed here, you may manufacture by arranging the several functional device 1a in parallel.

[Base substrate preparation process]
FIG. 6A shows a state in which the base substrate 2 on which the element portion 3 and the wiring portion 4 are formed is prepared.
The base substrate preparation step is a step of preparing the base substrate 2 on which the element portion 3, the wiring portion 4, and the like are formed and the lid portion 5 is joined as in the first embodiment.

[Base substrate processing process]
FIG. 6B shows a state where the cavity portion 21, the groove portion 24, and the depressed portion 26 are formed on the bonding surface 2 a of the base substrate 2.
The base substrate processing step is a step of forming the hollow portion 21, the groove portion 24, and the depressed portion 26 in the bonding surface 2a shown in FIG.
The cavity portion 21, the groove portion 24, and the depressed portion 26 are formed by forming a mask pattern (not shown) having an opening in a portion where these are formed on the bonding surface 2a, and etching the base substrate 2 by a wet etching method. Can be formed. In the base substrate processing step, the wet etching method is used as a method for forming the cavity portion 21, the groove portion 24, and the depressed portion 26, but the dry etching method may be used without being limited thereto.

[Wiring section forming process]
FIG. 6C shows a state in which the wiring part 4 is formed on the bonding surface 2 a of the base substrate 2.
The wiring portion forming step is a step of forming the wiring portion 4 (wirings 41, 42, 43) along the groove portions 24 (24a, 24b, 24c) formed on the joint surface 2a shown in FIG. is there.
Since the wiring part forming step is the same as the wiring part forming step in the functional device 1 described in the first embodiment, the description thereof is omitted.

[First joining step]
The first bonding step is a step of bonding the element substrate 103 to be the element portion 3 to the bonding surface 2a of the base substrate 2 as shown in FIG.
The first bonding step is a step of bonding the element substrate 103, which is a material for forming the element portion 3 in the element portion forming step described later, on the bonding surface 2a by an anodic bonding method.
In the first bonding step, when the bonding surface 2 a of the base substrate 2 and the first surface 103 a of the element substrate 103 are bonded, a space is formed between the bonding region 56 a serving as the inner bottom surface of the depressed portion 26 and the element substrate 103. And the bonding region 56a does not contact the element substrate 103.
Therefore, the first bonding step suppresses deficiency of Na ions (movable elements) in the bonding region 56a on the bonding surface 2a due to bonding of the element substrate 103 and the base substrate 2 provided with the depression 26. can do.
Here, the bonding region 56a is a portion where the base substrate 2 and the lid portion 5 are bonded, and is a virtual region that is provided on the inner bottom surface of the depressed portion 26 provided on the bonding surface 2a.

  In the method for manufacturing the functional device 1 described in the first embodiment, the depression 113 is formed in the element substrate 103 in advance. However, the formation is not essential in the functional device 1a of the present embodiment. For example, when the element substrate 103 on which the depressed portion 113 is formed is bonded in the first bonding step, the depressed portion is obtained when the base substrate 2 and the element substrate 103 are viewed in a plan view from a direction perpendicular to the bonding surface 2a. 26 and the depressed portion 113 are joined.

[Element part formation process / exposure process]
In the element portion forming step, the element substrate 103 is processed, and the fixed portions 31 and 32, the movable weight 33, the beam portions 34 and 35, the movable electrode portions 36 and 37, and the fixed electrode portions 38 and 39 constituting the element portion 3 are formed. It is a process of forming. The exposure process is a process of removing a part of the element substrate 103 bonded to the base substrate 2.
FIG. 6E shows a state in which the element substrate 103 is thinned to a thickness necessary for forming the element portion 3. The element portion forming step includes a step of thinning the element substrate 103 shown in FIG. Note that the element substrate 103 may be thinned as necessary.
FIG. 7F shows a state where the element portion 3 is formed. The element portion forming step includes a step of forming the element portion 3 by patterning the thinned element substrate 103 as shown in FIG. Further, a part of the element substrate 103 is removed so that the depressed portion 26 is exposed.
In the exposure process, the element substrate 103 is removed from the unnecessary part as the element part 3 simultaneously with the formation of the element part 3 in the element part forming process. By removing the element substrate 103, the depressed portion 26 that has been formed on the bonding surface 2a of the base substrate 2 first appears. As a result, the bonding region 56a that becomes the inner bottom surface of the depressed portion 26 that has not been bonded to the element substrate 103 is exposed, and the lid portion 5 is bonded in a second bonding step described later.
Since the other element part formation process and the exposure process are the same as the manufacturing method similar to the element part formation process in the functional device 1 described in the first embodiment, a part of the description is omitted.

[Second joining step]
FIG. 7G shows a state where the lid 5 is bonded to the base substrate 2.
The second joining step is a step of joining the lid portion 5 having the cavity 52 to the joining surface 2a.
The second bonding step includes a top surface 54a of the lid portion 5 and a bonding region 56a that is an inner bottom surface of the depressed portion 26 provided on the bonding surface 2a when viewed in a plan view from a direction perpendicular to the bonding surface 2a. The lid 5 and the base substrate 2 are joined so that and overlap.

In the second bonding step, the base substrate 2 and the lid 5 are bonded using an anodic bonding method.
In the second bonding step, the bonding region 56 a that is the inner bottom surface of the depressed portion 26 is not in contact (bonded) with the element substrate 103 in the first bonding step described above. Therefore, the deficiency of the movable element (Na ion) in the region does not occur.
Therefore, when the base substrate 2 and the lid portion 5 are joined in the second joining step, Na ions can be moved in the joining region 56a where they are joined, and the base substrate 2 and the lid portion are joined in the joining region 56a. 5 can be bonded to each other by electrostatic attraction.

  Since the other configuration and manufacturing method of the functional device 1a are the same as the configuration and manufacturing method of the functional device 1 described above in the first embodiment, the description thereof is omitted.

According to the second embodiment described above, the following effects can be obtained.
According to such a manufacturing method of the functional device 1a, the base substrate 2 is bonded to the element substrate 103 in the first bonding step, and is bonded to the lid portion 5 in the second bonding step.
In the base substrate 2 to be bonded to the element substrate 103 in the first bonding step, the depressed portion 26 is formed on the bonded surface 2a to be bonded. Therefore, the depressed portion is formed on the bonded surface 2a of the element substrate 103 and the base substrate 2. There is a gap between the portion where 113 is formed. Therefore, the base substrate 2 and the element substrate 103 are not joined at the portion where the depressed portion 26 is formed.
The lid 5 having the cavity 52 to be joined in the second joining process is joined to the base substrate 2 so that the element part 3 formed by the element part forming process is included in the cavity 52.
Here, a depression 26 is formed on the bonding surface 2a of the base substrate 2 bonded in the first bonding step so as to overlap with a bonding region 56a where the base substrate 2 and the lid 5 are bonded.
Thereby, the lid 5 and the element substrate 103 bonded to the bonding surface 2a of the base substrate 2 are not bonded redundantly. Further, deficiency of Na ions (movable elements) included in the base substrate 2 bonded to the lid 5 and the element substrate 103 is suppressed.
Therefore, in such a method for manufacturing the functional device 1a, even when the base substrate 2 and the element substrate 103, and the base substrate 2 and the lid 5 are joined in a plurality of steps, a reduction in joining force is suppressed. It can be firmly bonded by an anodic bonding method. Further, since it is not necessary to provide the depressed portion 113 in the element substrate 103 in a separate process, the production efficiency can be improved. In addition, since the base substrate 2 and the lid 5 are firmly bonded to each other in the method for manufacturing the functional device 1a, the functional device 1a that can suppress the oxidation of the element unit 3 included in the cavity 52 is provided. Can be manufactured.

[Third Embodiment]
A method for manufacturing a functional device according to the third embodiment will be described with reference to FIGS.
FIG. 8 and FIG. 9 are explanatory diagrams for explaining the manufacturing process of the functional device according to the third embodiment. 8 and 9 schematically show a cross section of a functional device equivalent to the portion indicated by line segment AA ′ in FIG. 1.

The functional device 1b according to the third embodiment is similar in structure to the functional device 1 described in the first embodiment, except that the manufacturing method includes a step of forming a protective film 70 that covers the bonding region 56a. .
Since other configurations are substantially the same as those of the functional device 1 described in the first embodiment, the same components are denoted by the same reference numerals and numerals, and description thereof is partially omitted, and the functional device 1b will be described. .

[Method for Manufacturing Functional Device 1b]
A method for manufacturing the functional device 1b will be described.
8 and 9 are cross-sectional views for explaining a manufacturing process of the functional device 1b, and schematically show a cross section similar to that of the functional device 1 along the line AA ′ shown in FIG.

The manufacturing method of the functional device 1b according to the present embodiment includes a substrate preparation step, a base substrate processing step, a protective film formation step, and a wiring portion formation step. In addition, the manufacturing method of the functional device 1b includes a first bonding step of bonding the element substrate 103 as the first substrate and the base substrate 2 as the second substrate, an element portion forming step, the base substrate 2 and the first substrate A second joining step for joining the lid portion 5 as the three substrates.
In the present embodiment, description will be made on the assumption that a single functional device 1b is formed. However, a plurality of functional devices 1b may be arranged in parallel.

[Base substrate preparation process]
FIG. 8A shows a state in which the base substrate 2 on which the element portion 3 and the wiring portion 4 are formed is prepared.
The base substrate preparation step is a step of preparing the base substrate 2 on which the element portion 3, the wiring portion 4, and the like are formed and the lid portion 5 is joined as in the first embodiment.

[Base substrate processing process]
FIG. 8B shows a state where the cavity 21 and the groove 24 are formed on the bonding surface 2 a of the base substrate 2.
The base substrate processing step is a step of forming the cavity portion 21 and the groove portion 24 in the joint surface 2a shown in FIG. Since the base substrate processing step is the same as the base substrate processing step in the functional device 1 described in the first embodiment, the description thereof is omitted.

[Wiring part forming step and protective film forming step]
FIG. 8C shows a state in which the wiring portion 4 and the protective film 70 are formed on the bonding surface 2 a of the base substrate 2.

The wiring portion forming step is a step of forming the wiring portion 4 (wiring 41, 42, 43) along the groove portion 24 (24a, 24b, 24c) formed on the bonding surface 2a shown in FIG. is there.
The wiring part forming step is the same as the method for manufacturing the functional device 1 described in the first embodiment, and a description thereof will be omitted.

The protective film forming step is a step of forming the protective film 70 on the bonding surface 2a shown in FIG.
The protective film forming step is a step of forming a protective film 70 that covers the bonding region 56a where the base substrate 2 and the lid portion 5 are bonded in a second bonding step described later.
The protective film 70 is formed on the bonding surface 2a by forming a mask pattern (not shown) having an opening in the portion where the protective film 70 is formed, and depositing a film forming material on the bonding surface 2a by a CVD (chemical vapor deposition) method. Can be formed. The material for forming the protective film 70 is not particularly limited, but it is sufficient that the base substrate 2 (bonding surface 2a) can be protected from the dry etching process used for patterning the element substrate 103 in the element portion forming process described later. . The protective film 70 of the present embodiment is preferably formed as a DLC (diamond-like carbon) film, for example. The DLC film has excellent seizure resistance and chemical stability, and can protect the bonding surface 2a in the bonding region 56a from damage such as dry etching in the first bonding process and the element part forming process described later. Moreover, the protective film 70 can be used as the material as long as it is resistant to the etching of the element substrate 103 formed of a silicon substrate in an element portion forming process described later. Examples thereof include a metal (chromium, gold, nickel, platinum, etc.) film, an oxide (silicon oxide, aluminum oxide) film, and a nitride film.
In the wiring portion forming step, the CVD method is used as a method of forming the wiring portion 4 on the bonding surface 2a. However, the method is not limited to this, and the wiring portion forming step may be formed by a vacuum evaporation method or a sputtering method.

[First joining step]
The first bonding step is a step of bonding the element substrate 103 to be the element portion 3 to the bonding surface 2a of the base substrate 2 as shown in FIG.
The first substrate bonding step is a step of bonding the element substrate 103, which is a material for forming the element portion 3 in the element portion forming step described later, on the bonding surface 2a by an anodic bonding method.
Here, as the element substrate 103 of the present embodiment, a substrate on which the depressed portion 113 is formed in advance is used as in the functional device 1 described in the first embodiment.
The depressed portion 113 is provided on the element substrate 103 so as to cover the bonding region 56a and the protective film 70 on the bonding surface 2a where the base substrate 2 and the lid portion 5 are bonded by a second bonding step described later. Further, in the first bonding step, the base substrate 2 and the element substrate 103 are bonded to each other when the protective film 70 and at least a part of the bonding region 56a are depressed when seen in a plan view from the direction perpendicular to the bonding surface 2a. This is performed so that the portion 113 is covered.

[Element part formation process / exposure process]
In the element portion forming step, the element substrate 103 is processed, and the fixed portions 31 and 32, the movable weight 33, the beam portions 34 and 35, the movable electrode portions 36 and 37, and the fixed electrode portions 38 and 39 constituting the element portion 3 are formed. It is a process of forming. The exposure process is a process of removing a part of the element substrate 103 bonded to the base substrate 2.
FIG. 8E shows a state where the element substrate 103 is thinned to a thickness necessary for forming the element portion 3. The method for manufacturing the functional device 1b according to the present embodiment includes a step of thinning the element substrate 103 as necessary, similarly to the method for manufacturing the functional device 1 according to the first embodiment.
FIG. 9F shows a state in which the element portion 3 is formed. In addition, a part of the element substrate 103 is removed and the bonding region 56a where the protective film 70 is formed is exposed.
The element portion forming step includes a step of forming the element portion 3 by patterning the thinned element substrate 103 as shown in FIG.
The element portion 3 is formed by patterning the fixed portions 31 and 32, the movable weight 33, the beam portions 34 and 35, the movable electrode portions 36 and 37, and the fixed electrode portions 38 and 39 on the element substrate 103, for example, dry etching. It can be done using the law.
In the method for manufacturing the functional device 1b, since the protective film 70 is formed so as to cover the bonding region 56a, the bonding surface 2a (bonding region 56a) is protected from damage due to dry etching in the element portion forming process, and will be described later. Adhesiveness of the joint surface between the base substrate 2 and the lid 5 performed in the second joining step can be enhanced.

In the element portion forming step, the element substrate 103 is patterned to form the element portion 3 and the element substrate 103 overlapping the bonding region 56a is removed, and then the protective film 70 formed in the protective film forming step is peeled off. The method for removing the protective film 70 is not particularly limited. For example, a wet etching method using an etchant having etching resistance with respect to the base substrate 2 and the element portion 3 can be used.
By removing the protective film 70, the bonding surface 2a that is the bonding region 56a protected by the protective film 70 appears.

[Second joining step]
FIG. 9G shows a state where the lid 5 is bonded to the base substrate 2.
The second joining step is a step of joining the lid portion 5 having the cavity 52 to the joining surface 2a.
Here, as the lid portion 5 of the present embodiment, one having a cavity 52 formed in advance on the surface 5a to be joined to the base substrate 2 is used.
In the second bonding step, the top surface 54a of the lid portion 5 provided with the cavity 52 and the bonding region 56a on the bonding surface 2a overlap when viewed in a plane from the direction perpendicular to the bonding surface 2a. This is a step of joining the base substrate 2 and the lid 5.
In the second bonding step, the base substrate 2 and the lid 5 are bonded using an anodic bonding method. In the second bonding step, since the depression 113 is formed in the element substrate 103 in the first bonding step described above and the protective film 70 covering the bonding region 56a is formed, the bonding region 56a is connected to the element substrate 103. It is not abutted (joined). Therefore, the deficiency of Na ions (movable elements) in the bonding region 56a does not occur in the first bonding step.
Therefore, when the base substrate 2 and the lid portion 5 are bonded in the second bonding step, Na ions (movable elements) can be moved in the bonding region 56a to which these are bonded, and the base substrate can be moved in the bonding region 56a. 2 and the lid 5 are covalently bonded by electrostatic attraction and can be firmly bonded.

According to the third embodiment described above, the following effects can be obtained.
According to such a manufacturing method of the functional device 1b, the protective film 70 covering the bonding region 56a where the base substrate 2 and the lid portion 5 are bonded is formed prior to the element portion forming step. By forming the protective film 70, the bonding region 56a can be protected from damage caused by, for example, dry etching used in the element portion forming process.
Therefore, the joining force between the base substrate 2 and the lid part 5 joined in the second joining step can be further increased. Therefore, in such a method for manufacturing the functional device 1b, since the base substrate 2 and the lid portion 5 are firmly bonded, the functional device 1b that can suppress oxidation of the element portion 3 included in the cavity 52 is provided. Can be manufactured.

(Example)
With reference to FIG. 10 to FIG. 12, an example to which any one of the functional device 1 and the functional devices 1 a and 1 b according to the embodiment of the present invention (hereinafter collectively referred to as the functional device 1) is applied. While explaining.

[Electronics]
First, an electronic apparatus to which the functional device 1 according to an embodiment of the present invention is applied will be described with reference to FIGS.

  FIG. 10 is a perspective view schematically illustrating a configuration of a laptop (or mobile) personal computer as an electronic apparatus including the functional device according to the embodiment of the invention. In this figure, a laptop personal computer 1100 includes a main body portion 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display portion 1008. The display unit 1106 has a hinge structure portion with respect to the main body portion 1104. It is supported so that rotation is possible. Such a laptop personal computer 1100 incorporates a functional device 1 that functions as an acceleration sensor or the like for detecting acceleration applied to the laptop personal computer 1100 and displaying the acceleration on the display unit 1106. Has been. Such a functional device 1 can improve the reliability by increasing the bonding strength between the base substrate 2 and the lid portion 5 and increasing the airtightness in the cavity 52 in which the element portion 3 is accommodated. Therefore, a highly reliable laptop personal computer 1100 can be obtained.

  FIG. 11 is a perspective view schematically illustrating a configuration of a mobile phone (including PHS) as an electronic apparatus including the functional device according to the embodiment of the invention. In this figure, a cellular phone 1200 includes a plurality of operation buttons 1202, a earpiece 1204, and a mouthpiece 1206, and a display portion 1208 is disposed between the operation buttons 1202 and the earpiece 1204. Such a mobile phone 1200 incorporates a functional device 1 that functions as an acceleration sensor or the like for detecting an acceleration applied to the mobile phone 1200 and assisting the operation of the mobile phone 1200. Such a functional device 1 increases the bonding strength between the base substrate 2 and the lid 5 and increases the airtightness in the cavity 52 in which the element 3 is accommodated, thereby suppressing the oxidation of the element 3 and improving the reliability. Can be increased. Therefore, a highly reliable mobile phone 1200 can be obtained.

FIG. 12 is a perspective view schematically illustrating a configuration of a digital still camera as an electronic apparatus including the functional device according to the embodiment of the present invention. 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 image sensor such as a CCD (Charge Coupled Device). An imaging signal (image signal) is generated.
A display unit 1308 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 1308 displays an object as an electronic image. Functions as a viewfinder. 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 1308 and presses the shutter button 1306, the CCD image pickup signal at that time is transferred and stored in the memory 1310. 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 drawing, a liquid crystal display 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 1310 is output to the liquid crystal display 1430 or the personal computer 1440 by a predetermined operation. In such a digital still camera 1300, in order to operate a function for protecting the digital still camera 1300 from the fall, a functional device 1 that functions as an acceleration sensor that detects acceleration due to the fall is built in. Such a functional device 1 increases the bonding strength between the base substrate 2 and the lid 5 and increases the airtightness in the cavity 52 in which the element 3 is accommodated, thereby suppressing the oxidation of the element 3 and improving the reliability. Can be increased. Therefore, a highly reliable digital still camera 1300 can be obtained.

  The functional device 1 according to an embodiment of the present invention includes, for example, an inkjet in addition to the laptop personal computer (mobile personal computer) in FIG. 10, the mobile phone in FIG. 11, and the digital still camera in FIG. Dispenser (eg inkjet printer), 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 (E.g., vehicle, aircraft, ship instrumentation), It can be applied to electronic devices of the light simulator such.

[Moving object]
FIG. 13 is a perspective view schematically showing an automobile as an example of a moving body. In the automobile 1500, the functional device 1 that functions as an acceleration sensor is mounted on various control units. For example, as shown in the figure, an automobile 1500 as a moving body includes an electronic control unit (ECU) 1508 that includes a functional device 1 that detects the acceleration of the automobile 1500 and controls the output of the engine. Is mounted on the vehicle body 1507. By detecting the acceleration and controlling the engine to an appropriate output corresponding to the posture of the vehicle body 1507, an automobile 1500 as an efficient moving body with reduced consumption of fuel and the like can be obtained.
In addition, the functional device 1 can be widely applied to a vehicle body posture control unit, an anti-lock brake system (ABS), an air bag, and a tire pressure monitoring system (TPMS).
Such a functional device 1 increases the bonding strength between the base substrate 2 and the lid 5 and increases the airtightness in the cavity 52 in which the element 3 is accommodated, thereby suppressing the oxidation of the element 3 and improving the reliability. Can be increased. Therefore, the mobile object 1500 with high reliability can be obtained.

DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Functional device, 2 ... Base substrate, 2a ... Bonding surface, 3 ... Element part, 4 ... Wiring part, 5 ... Cover part, 5a ... Surface to be joined, 21 ... Hollow part, 24 ... Groove part, 26 ... Depressed part, 31, 32 ... Fixed part, 33 ... Movable weight, 34, 35 ... Beam part, 36, 37 ... Movable electrode part, 38, 39 ... Fixed electrode part, 41, 42, 43 ... Wiring, 44, 45, 46 ... pad electrode, 52 ... cavity, 54a ... top surface, 56a ... bonding region, 70 ... protective film, 103 ... element substrate, 103a ... first surface, 113 ... depression, 341, 342 ... beam, 381, 382, 391, 392 ... fixed electrode, 1100 ... laptop personal computer, 1200 ... mobile phone, 1300 ... digital still camera, 1500 ... automobile.

Claims (7)

Preparing a first substrate having a depression on the first surface and a second substrate;
A first bonding step of bonding the first surface side of the first substrate to the second substrate;
An exposure step of removing a substrate portion including the depressed portion of the first substrate and exposing a bonding surface of the second substrate overlapping the depressed portion in plan view;
A third substrate is placed on the bonding surface, and the second substrate and the third substrate are bonded with the first substrate positioned between the second substrate and the third substrate. A method for manufacturing a functional device, comprising two bonding steps. Preparing a second substrate having a depression on the first surface and a first substrate;
A first bonding step of bonding the first substrate to the first surface of the second substrate;
An exposing step of removing the substrate portion of the first substrate that overlaps the recessed portion of the second substrate in plan view, and exposing the recessed portion;
A third substrate is placed on the depressed portion, and the second substrate and the third substrate are joined in a state where the first substrate is positioned between the second substrate and the third substrate. A method for manufacturing a functional device, comprising two bonding steps. In the manufacturing method of the functional device of Claim 1 or 2,
The method of manufacturing a functional device, wherein the first bonding step and the second bonding step are bonded using anodic bonding. In the manufacturing method of the functional device as described in any one of Claims 1 thru | or 3,
A method of manufacturing a functional device, comprising: an element part forming step of processing the first substrate to form a functional device after the first bonding step. In the manufacturing method of the functional device of Claim 4,
Prior to the element portion forming step, the bonding area of the third substrate in the second substrate is covered with a protective film.   An electronic apparatus comprising a functional device manufactured by the method for manufacturing a functional device according to any one of claims 1 to 5.   A moving body on which a functional device manufactured by the method for manufacturing a functional device according to any one of claims 1 to 5 is mounted.

Images