PHYSICAL QUANTITY SENSOR, INERTIAL MEASUREMENT UNIT, AND METHOD FOR MANUFACTURING PHYSICAL QUANTITY SENSOR

Abstract

To provide a physical quantity sensor that prevents sticking of a movable body due to excessive impact, an inertial measuring device, and a method for manufacturing the physical quantity sensor.SOLUTION: A physical quantity sensor 10 comprises: a substrate 11; a movable body 33 that is fixed to a fixing part 13 provided on the substrate 11 and displaceable in a predetermined direction; movable electrodes 34, 35, 36 that are provided on the movable body 33; stationary electrodes 37, 38, 39 that are provided on the substrate 11 and have a surface composed of metal, an alloy of the metal, or nitride; a lid body 21 that accommodates the movable body 33 together with the substrate 11; and anti-stiction layers 53 that are provided at positions on the substrate 11 or the lid body 21 with which the movable body 33 can be in contact, and are selectively arranged not to be provided on the surfaces of the stationary electrodes 37, 38, 39.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a physical quantity sensor, an inertial measurement unit, and a method for manufacturing a physical quantity sensor. [Background technology]

[0002] In recent years, physical quantity sensors manufactured using MEMS (Micro Electro Mechanical Systems) technology have been developed. For example, Patent Document 1 describes such a physical quantity sensor, which includes a substrate, a movable body arranged on the substrate, having first and second mass parts, and seesaw-like swinging about a rotation axis, and first and second fixed electrodes arranged on the substrate and facing the first and second mass parts, and can detect vertical acceleration based on a change in electrostatic capacitance between the first and second mass parts of the movable body, which have different rotation moments around the rotation axis, and the first and second fixed electrodes arranged at positions facing each other. In addition, this physical quantity sensor has protrusions on the substrate that protrude toward the first and second mass portions to prevent contact between the movable body and the first and second fixed electrodes when the movable body oscillates excessively in a seesaw manner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-24098 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the physical quantity sensor described in Patent Document 1 is subjected to strong external vibrations or impacts, excessive seesaw oscillation causes the movable body to collide with the protrusion, and if the movable body acts as a single rigid body and repeatedly collides with a constant energy, there is a risk that a sticking phenomenon called stiction will occur between the movable body and the protrusion. [Means for solving the problem]

[0005] The physical quantity sensor comprises a substrate, a movable body fixed to a fixed portion provided on the substrate and displaceable in a predetermined direction, a movable electrode provided on the movable body, a fixed electrode provided on the substrate and having a surface made of a metal, an alloy of the metal, or a nitride, a lid that houses the movable body together with the substrate, and an anti-stiction layer selectively disposed at a position on the substrate or the lid that can be contacted by the movable body and not on the surface of the fixed electrode.

[0006] The inertial measurement device includes the above-described physical quantity sensor and a control unit that performs control based on a detection signal output from the physical quantity sensor.

[0007] A manufacturing method for a physical quantity sensor includes the steps of forming, on a substrate, a movable body fixed to a fixed portion provided on the substrate and displaceable in a predetermined direction, a movable electrode provided on the movable body, and a fixed electrode provided on the substrate and having a surface made of a metal, an alloy of the metal, or a nitride; preparing a lid having a through hole; joining the lid to the substrate to accommodate the movable body between the lid and the substrate; forming an anti-stiction layer on surfaces of the lid, the movable body, and the substrate via the through hole; heating the lid, the movable body, and the substrate to remove the anti-stiction layer on the fixed electrode; and blocking the through hole. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view showing a schematic structure of a physical quantity sensor according to a first embodiment. [Diagram 2] Cross-sectional view taken along line AA in FIG. [Diagram 3] FIG. 2 is a plan view showing a schematic structure of a substrate. [Figure 4] FIG. 2 is a diagram illustrating a silane coupling agent. [Diagram 5] FIG. 2 is a diagram illustrating a silane coupling agent. [Figure 6] FIG. 2 is a diagram illustrating a silane coupling agent. [Figure 7] FIG. 4 is a flowchart showing a method for manufacturing the physical quantity sensor according to the first embodiment. [Figure 8] 1A to 1C are cross-sectional views illustrating a method for manufacturing a physical quantity sensor. [Figure 9] 1A to 1C are cross-sectional views illustrating a method for manufacturing a physical quantity sensor. [Figure 10] 1A to 1C are cross-sectional views illustrating a method for manufacturing a physical quantity sensor. [Figure 11] 1A to 1C are cross-sectional views illustrating a method for manufacturing a physical quantity sensor. [Figure 12] 1A to 1C are cross-sectional views illustrating a method for manufacturing a physical quantity sensor. [Figure 13] 1A to 1C are cross-sectional views illustrating a method for manufacturing a physical quantity sensor. [Figure 14] 1A to 1C are cross-sectional views illustrating a method for manufacturing a physical quantity sensor. [Figure 15] 1A to 1C are cross-sectional views illustrating a method for manufacturing a physical quantity sensor. [Figure 16] FIG. 11 is a plan view showing a schematic structure of a physical quantity sensor according to a second embodiment. [Figure 17] 17 is a cross-sectional view taken along line BB in FIG. 16 . [Figure 18] FIG. 2 is a plan view showing a schematic structure of a substrate. [Figure 19] FIG. 11 is a plan view showing a schematic structure of a physical quantity sensor according to a third embodiment. [Figure 20] 20 is a cross-sectional view taken along line CC in FIG. 19 . [Figure 21] FIG. 2 is a plan view showing a schematic structure of a substrate. [Figure 22] FIG. 11 is a cross-sectional view showing a schematic structure of a physical quantity sensor according to a fourth embodiment. [Diagram 23] FIG. 13 is an exploded perspective view showing a schematic configuration of an inertial measurement unit including a physical quantity sensor according to a fifth embodiment. [Figure 24] FIG. 24 is a perspective view of the substrate of FIG. 23 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 1. First embodiment 1.1.Physical Quantity Sensor First, a physical quantity sensor 10 according to a first embodiment will be described with reference to FIGS. 1, 2, and 3, taking an acceleration sensor that detects acceleration in the vertical direction as an example. 1, for convenience of explaining the internal configuration of the physical quantity sensor 10, a state in which the lid 21 is removed is illustrated, and an anti-stiction layer 53 provided inside the physical quantity sensor 10 is omitted. Also, in FIGS. 1, 2, and 3, wiring provided on the substrate 11 is omitted.

[0010] For ease of explanation, the plan views, cross-sectional views, and perspective views below show three mutually orthogonal axes, the X-axis, the Y-axis, and the Z-axis. The direction along the X-axis is called the "X-direction", the direction along the Y-axis is called the "Y-direction", and the direction along the Z-axis is called the "Z-direction". The tip side of the arrow in each axial direction is called the "plus side", the base side is called the "minus side", the plus side of the Z direction is called the "upper", and the minus side of the Z direction is called the "lower". The Z direction is along the vertical direction, and the XY plane is along the horizontal plane.

[0011] 1 and 2 can detect acceleration in the Z direction which is the vertical direction of the sensor element 30. Such a physical quantity sensor 10 has a substrate 11, a sensor element 30 arranged on the substrate 11, and a lid 21 bonded to the substrate 11 and covering the sensor element 30.

[0012] As shown in FIG. 1 and FIG. 3, the substrate 11 has an extension in the X-direction and the Y-direction, and a thickness in the Z-direction. In addition, as shown in FIG. 2, the substrate 11 has a recess 14 recessed downward. In a plan view from the Z-direction, the recess 14 contains the sensor element 30 inside and is formed larger than the sensor element 30. The recess 14 functions as a relief portion for swinging the sensor element 30. In addition, the substrate 11 has a fixing portion 13 protruding from an inner bottom surface 15 of the recess 14 toward the sensor element 30, and the sensor element 30 is joined onto the fixing portion 13. This allows the sensor element 30 to be fixed to the substrate 11 in a state where it is spaced from the inner bottom surface 15 of the recess 14.

[0013] Further, a first fixed electrode 37, a second fixed electrode 38, and a third fixed electrode 39 serving as a dummy electrode are disposed on the inner bottom surface 15 of the recess 14. The first fixed electrode 37 and the second fixed electrode 38 have substantially the same area. The first fixed electrode 37 and the second fixed electrode 38 are each connected to a QV amplifier of an external device (not shown), and the capacitance difference therebetween is detected as an electrical signal by a differential detection method. Therefore, it is desirable that the first fixed electrode 37 and the second fixed electrode 38 have the same area.

[0014] Furthermore, the substrate 11 is provided with connection terminals 16 for electrically connecting an external device to the fixed electrodes 37, 38, and 39 on the upper surface 12 in an area where the recess 14 is not provided.

[0015] The substrate 11 is, for example, Na + For example, a glass substrate made of a borosilicate glass such as Pyrex (registered trademark) glass or Tempax (registered trademark) glass can be used. However, the substrate 11 is not particularly limited, and for example, a silicon substrate or a quartz substrate can be used.

[0016] The fixed electrodes 37, 38, 39 have surfaces made of metals such as Au, Pt, Ag, Cu, Al, Ti, alloys containing these metals, or nitrides such as TiN, GaN, ZnN, InN, etc. In particular, metals with low surface tension and surface energy are suitable, and noble metals such as Au, Pt, Pd, Rh, Ir, Ru, Os, Ag, etc. are preferable. For example, Pt has a surface tension of 1.8 mJ / m 2 The contact angle of pure water is about 96°. The contact angles of other precious metals with pure water are, for example, 95° and 105° for Au and Pd, respectively.

[0017] 2, the lid body 21 is formed at a position where the recess 22 recessed upward overlaps with the recess 14 of the substrate 11. The lid body 21 is joined onto the substrate 11 with the sensor element 30 accommodated in the recess 22. The lid body 21 and the substrate 11 form an internal space S for accommodating the sensor element 30 therein.

[0018] The lid 21 is provided with a through hole 25 that communicates the upper surface 24 and the inner bottom surface 23 of the recess 22 in the thickness direction. A metal layer 26 is provided on the side surface of the through hole 25, and the through hole 25 is blocked and sealed by a sealing member 52 that contacts the metal layer 26. The metal layer 26 is provided to increase the adhesion between the through hole 25 and the sealing member 52. The material of the metal layer 26 is preferably a precious metal such as Au, Pt, Pd, Rh, Ir, Ru, Os, Ag, or an alloy containing them. In this embodiment, the sealing member 52 is an AuGe alloy, the metal layer 26 is an Au / Ti laminated film of Ti as an adhesion layer with the through hole 25, and Au to form an alloy with the sealing member 52.

[0019] The internal space S formed by sealing the through-hole 25 with the sealing member 52 is an airtight space, and is preferably filled with an inert gas such as nitrogen, helium, or argon, and is at approximately atmospheric pressure with an operating temperature of about -40°C to 125°C. However, the atmosphere in the internal space S is not particularly limited, and may be, for example, in a reduced pressure state or a pressurized state.

[0020] In this embodiment, the sealing member 52 is melted to seal the through hole 25, but this is not limited to this, and the through hole 25 may be directly melted by a laser without using the sealing member 52 to seal the through hole 25.

[0021] 2 and 3, an anti-stiction layer 53 is provided in the internal space S. The anti-stiction layer 53 is selectively provided at a position in the substrate 11 or the lid 21 where it can come into contact with the movable body 33, and is not selectively provided on the fixed electrodes 37, 38, 39 and the surface of the metal layer 26 provided in the through hole 25. The anti-stiction layer 53 is provided on the inner bottom surface 15 and the inner side wall of the recess 14 provided in the substrate 11, the side wall of the fixed part 13 provided in the substrate 11, and the inner bottom surface 23 and the inner side wall which are the surfaces of the recess 22 provided in the lid 21 on the movable body 33 side. The anti-stiction layer 53 is arranged so as not to be provided on the joint surface with the fixed part 13 of the sensor element 30 and the joint part 50 between the lid 21 and the substrate 11.

[0022] The anti-stiction layer 53 is made of a coupling agent of an organic silicon compound such as an organosilicon compound, and the organosilicon compound is alkylsilane, phenylsilane, phenylalkylsilane, alkoxysilanol, alkylsilanol, phenylsilanol, phenylalkylsilanol, alkoxysiloxane, alkylsiloxane, phenylsiloxane, phenylalkylsiloxane, hexamethyldisilazane, etc. These organic silicon compound coupling agents lower the surface energy, and therefore have the effect of lowering the probability of stiction occurring. For example, when hexamethyldisilane is used, the surface energy is 20 mJ / m 2 or less, which is preferable. At this time, the surface state becomes hydrophobic, and the contact angle with pure water becomes approximately 85° or more. In this embodiment, the anti-stiction layer 53 is formed on all surfaces that may come into contact with the movable body 33, except for the surfaces of the fixed electrodes 37, 38, and 39, so that the adhesive force of the two contacting surfaces can be reduced, and the occurrence of stiction with the movable body 33 can be reduced.

[0023] The reason why the anti-stiction layer 53 is not selectively disposed on the surfaces of the fixed electrodes 37, 38, and 39 is to avoid increasing unnecessary capacitance between the fixed electrodes 37, 38, and 39 and the movable electrodes 34, 35, and 36. The reason why the anti-stiction layer 53 is not selectively disposed on the surface of the metal layer 26 provided in the through-hole 25 is to increase the adhesion between the metal layer 26 and the sealing member 52.

[0024] For example, a silicon substrate can be used as the lid 21. However, the present invention is not limited to this, and for example, a glass substrate or a quartz substrate can be used. The method for bonding the substrate 11 and the lid 21 is not limited to this, and can be appropriately selected depending on the materials of the substrate 11 and the lid 21. For example, anodic bonding, activation bonding in which bonding surfaces activated by plasma irradiation are bonded together, bonding using a bonding material such as glass frit, metal eutectic bonding in which metal films formed on the upper surface of the substrate 11 and the lower surface of the lid 21 are bonded together, and the like can be used.

[0025] The sensor element 30 is formed by etching a conductive silicon substrate doped with impurities such as phosphorus (P), boron (B), or arsenic (As), in particular by vertical processing using the Bosch process, which is a deep etching technique.

[0026] 1, the sensor element 30 has a holding part 31 joined onto the fixed part 13, a movable body 33 disposed opposite the substrate 11 and displaceable in a predetermined direction relative to the holding part 31, and a support beam 32 that connects the holding part 31 and the movable body 33 and extends in the Y direction. When acceleration is applied along the Z direction, the movable body 33 swings around the support beam 32 as a rotation axis J1 while torsionally deforming the support beam 32. In other words, the movable body 33 is configured to be able to swing in a seesaw manner relative to the holding part 31 with the rotation axis J1 as a central axis.

[0027] The movable body 33 has a rectangular shape with its longer sides in the X direction in a plan view from the Z direction. The movable body 33 has a first movable electrode 34 located on the negative side in the X direction with respect to the rotation axis J1, a second movable electrode 35 located on the positive side in the X direction with respect to the rotation axis J1, and a third movable electrode 36 connected to the second movable electrode 35. The first movable electrode 34, the second movable electrode 35, and the third movable electrode 36 are arranged to overlap with a first fixed electrode 37, a second fixed electrode 38, and a third fixed electrode 39 provided on the inner bottom surface 15 of the substrate 11, respectively, in a plan view from the Z direction.

[0028] Moreover, the movable body 33 located on the positive side of the X direction with respect to the rotation axis J1 is configured to be longer in the X direction than the first movable electrode 34, which is the movable body 33 located on the negative side of the X direction with respect to the rotation axis J1, because the second movable electrode 35 and the third movable electrode 36 are connected. Therefore, the movable body 33 located on the positive side of the X direction with respect to the rotation axis J1 has a larger area and a larger mass than the movable body 33 located on the negative side of the X direction with respect to the rotation axis J1 in a plan view, and therefore has a larger rotation moment when acceleration is applied than the movable body 33 located on the negative side of the X direction. Due to this difference in rotation moment, when acceleration is applied, the movable body 33 seesaws around the rotation axis J1. The seesaws mean that when the first movable electrode 34 is displaced on the positive side of the Z direction, the second movable electrode 35 is displaced on the negative side of the Z direction, and conversely, when the first movable electrode 34 is displaced on the negative side of the Z direction, the second movable electrode 35 is displaced on the positive side of the Z direction.

[0029] Moreover, the movable body 33 has an opening between the first movable electrode 34 and the second movable electrode 35, and the holding portion 31 and the support beam 32 are disposed in the opening. By adopting such a shape, the sensor element 30 can be made compact.

[0030] When the physical quantity sensor 10 is driven, a drive signal is applied to the sensor element 30, so that a capacitance Ca is formed between the first movable electrode 34 and the first fixed electrode 37. Similarly, a capacitance Cb is formed between the second movable electrode 35 and the second fixed electrode 38. In a natural state where no acceleration is applied, the capacitances Ca and Cb are approximately equal to each other.

[0031] When acceleration is applied to the physical quantity sensor 10, the movable body 33 seesaws around the rotation axis J1. Due to this seesaw swing of the movable body 33, the gap between the first movable electrode 34 and the first fixed electrode 37 and the gap between the second movable electrode 35 and the second fixed electrode 38 change in opposite phases, and accordingly, the capacitances Ca and Cb change in opposite phases to each other. Therefore, the physical quantity sensor 10 can detect acceleration in the Z direction based on the difference between the capacitance values ​​of the capacitances Ca and Cb.

[0032] Next, the anti-stiction layer 53 used in the physical quantity sensor 10 of this embodiment will be described with reference to FIGS. The organosilicon compound G constituting the anti-stiction layer 53 is generally called a silane coupling agent, and is used when forming a water- and oil-repellent organic thin film on the surface of an inorganic substrate such as glass or metal.

[0033] The chemical structure of a silane coupling agent is Y-Si(OR)3, in which one silicon (Si) atom is bonded to one organic functional group (Y) and three hydrolyzable groups (OR), as shown in Figure 4. When this is hydrolyzed, the OH generated from the hydrolyzable groups (OR) and silicon generate silanol (Si-OH) groups.

[0034] The generated silanol (Si-OH) groups undergo dehydration condensation with the silanol (Si-OH) groups of other silane coupling agents to form chains. As shown in Figure 5, these chains of silanol (Si-OH) groups of the silane coupling agents form hydrogen bonds with the hydroxyl (-OH) groups of the inorganic material and are fixed to the surface of the inorganic material. After that, they undergo dehydration condensation to adhere to the inorganic surface with strong covalent bonds.

[0035] As shown in FIG. 6, the silane coupling agent also adheres to the surface of glass or metal formed on glass by covalent bonds. However, when heated, the silane coupling agent adhered to the glass surface remains adhered, but depending on the type of metal, the silane coupling agent on the metal surface may peel off. Metals from which the silane coupling agent on the surface peels off when heated include metals such as Au, Pt, Ag, Cu, and Al, or alloys containing these metals. Similarly, the silane coupling agent on the surface of nitrides such as TiN, GaN, ZnN, and InN can be easily peeled off when heated. In particular, metals from which the silane coupling agent on the surface peels off easily when heated include precious metals such as Au, Pt, Pd, Rh, Ir, Ru, Os, and Ag. Therefore, in the physical quantity sensor 10 of this embodiment, the anti-stiction layer 53 provided on the surfaces of the fixed electrodes 37, 38, and 39 provided on the substrate 11 and on the surface of the metal layer 26 provided on the lid 21 can be removed by heating before sealing the through-hole 25. Note that, although a silane coupling agent having a silanol (Si-OH) group is used in the anti-stiction layer 53 of this embodiment, any material that can be desorbed from the metal surface may be used, and other materials such as fluorinated silane, fluorinated ether, and fluorinated acrylic may also be used.

[0036] The thickness of the anti-stiction layer 53 is preferably 0.1 nm to 10.0 nm inclusive. If the thickness is less than 0.1 nm, the adhesive force between the two contacting surfaces cannot be sufficiently reduced, and if the thickness is more than 10.0 nm, the deposition time is long and removal from the metal surface by heating becomes difficult.

[0037] In the physical quantity sensor 10 of this embodiment, the anti-stiction layer 53 is selectively disposed at a position on the substrate 11 or the lid 21 where the movable body 33 can come into contact, and not on the surfaces of the fixed electrodes 37, 38, and 39, thereby reducing the occurrence of stiction due to contact between the substrate 11 or the lid 21 and the movable body 33.

[0038] In addition, since the anti-stiction layer 53 is not disposed on the surfaces of the fixed electrodes 37, 38, 39 made of precious metals such as Au, Pt, Pd, Rh, Ir, Ru, Os, and Ag provided on the substrate 11, no unnecessary capacitance is generated between the movable electrodes 34, 35, 36 of the movable body 33 and the fixed electrodes 37, 38, 39. Therefore, it is possible to reduce the deterioration of the detection accuracy of the acceleration. On the other hand, it is possible to completely cover all the surfaces of the recess 22, the recess 14, and the sensor element 30 with the anti-stiction layer 53 having low surface energy and the fixed electrodes 37, 38, 39 made of metals having low surface tension and surface energy. In other words, it is possible to completely surround the sensor element 30 and the space around it with a hydrophobic material. Therefore, it is possible to reduce the stiction phenomenon caused by repeated collisions with a certain energy.

[0039] 1.2. Manufacturing method of physical quantity sensor Next, a method for manufacturing the physical quantity sensor 10 of this embodiment will be described with reference to FIGS. As shown in FIG. 7, the manufacturing method for the physical quantity sensor 10 of this embodiment includes a substrate preparation step, a sensor element substrate bonding step, a sensor element formation step, a lid preparation step, a lid bonding step, an anti-stiction layer formation step, an anti-stiction layer removal step, and a sealing step.

[0040] 1.2.1.Substrate preparation process First, in step S101, a flat glass containing, for example, alkali metal ions is prepared, and a recess 14 and a fixing portion 13 are formed on the glass by photolithography and etching. After that, a film of a precious metal such as Au, Pt, Pd, Rh, Ir, Ru, Os, Ag, etc. is formed on the inner bottom surface 15 of the recess 14 and the upper surface 12 of the substrate 11 by a sputtering method, and fixed electrodes 37, 38, 39 and wiring (not shown) are formed on the inner bottom surface 15 of the recess 14 by photolithography and etching, and a connection terminal 16 and wiring (not shown) are formed on the upper surface 12 of the substrate 11. However, in the case of Pt, patterning may be performed by lift-off technology. This completes the preparation of the substrate 11 as shown in FIG. 8.

[0041] 1.2.2. Sensor element substrate bonding process 8, a sensor element substrate 55 made of silicon is bonded onto the fixing portion 13 of the substrate 11 by, for example, anodic bonding. A recess 56 is formed in the sensor element substrate 55 so that the connection terminal 16 and the sensor element substrate 55 do not interfere with each other.

[0042] 1.2.3.Sensor element formation process In step S103, as shown in FIG. 9, the sensor element substrate 55 is thinned, and then vertically processed by the Bosch process, which is a deep etching technique, to form the sensor element 30 having the movable body 33 on which the movable electrodes 34, 35, and 36 are formed.

[0043] 1.2.4. Lid preparation process In step S104, a flat silicon substrate is prepared, and a recess 22 and a through hole 25 are formed in the silicon substrate by photolithography and etching. Then, a film of a precious metal such as Au, Pt, Pd, Rh, Ir, Ru, Os, Ag, etc. is formed on the side surface of the through hole 25 and the upper surface 24 of the lid 21 by sputtering, and a metal layer 26 is formed on the side surface of the through hole 25 and a part of the upper surface 24 of the lid 21 by photolithography and etching. This completes the preparation of the lid 21 as shown in Fig. 10. By forming the through hole 25 in the lid 21 in advance, excess gas generated in the lid bonding process described later can be efficiently discharged.

[0044] 1.2.5. Lid joining process In step S105, as shown in FIG. 10, the lid 21 is placed on the substrate 11 so that the inner bottom surface 15 of the recess 14 of the substrate 11 faces the inner bottom surface 23 of the recess 22 of the lid 21, and the recess 14 of the substrate 11 overlaps the recess 22 of the lid 21, and the substrate 11 and the lid 21 are bonded, for example, by anodic bonding. By this process, the sensor element 30 having the movable body 33 is accommodated between the substrate 11 and the lid 21. The bonding between the substrate 11 and the lid 21 may be performed by low-melting glass frit bonding, metal eutectic bonding, direct bonding, etc., other than anodic bonding, as long as it has a strength that does not peel off when diced. However, in this bonding process, desorbed gas generated from the substrate 11, the lid 21, or a bonding material not shown can be efficiently discharged from the through hole 25.

[0045] 1.2.6.Anti-stiction layer formation process In step S106, as shown in FIG. 11, the organosilicon compound G in a gaseous state is inserted through the through hole 25 into the internal space S formed by the recess 14 of the substrate 11 and the recess 22 of the lid 21. By inserting the organosilicon compound G in a gaseous state into the internal space S, as shown in FIG. 12, an anti-stiction layer 53 is formed on the inner bottom surface 15 and inner side wall of the recess 14 provided in the substrate 11, the side wall of the fixed part 13 provided in the substrate 11, the surfaces of the fixed electrodes 37, 38, and 39 provided in the substrate 11, the inner bottom surface 23 and inner side wall of the recess 22 provided in the lid 21, and the surface of the movable body 33 except for the joint surface with the fixed part 13 of the sensor element 30, as shown in FIG. 12. The anti-stiction layer 53 is also formed on the surface of the metal layer 26 provided in the through hole 25. The anti-stiction layer 53 is provided after the lid 21 and the substrate 11 are joined, and is not disposed at the joint 50 between the lid 21 and the substrate 11. In this embodiment, as the organosilicon compound G, hexamethyldisilazane was used.

[0046] 1.2.7. Anti-stiction layer removal process In step S107, for example, the anti-stiction layer 53 is formed in a thermostatic bath or the like, and the substrate 11 to which the movable body 33 and the lid body 21 are joined is placed and heated, so that only the anti-stiction layer 53 attached to the surfaces of the fixed electrodes 37, 38, 39 and the metal layer 26 can be selectively removed, as shown in Fig. 13. At this time, the organosilicon compound G attached to the outer periphery of the lid body 21 other than the internal space S is exposed to the outside air and is desorbed and sublimated.

[0047] 1.2.8. Sealing process In step S108, as shown in FIG. 14, sealing member 52 is placed in through hole 25, and then laser light L is irradiated onto sealing member 52 to melt sealing member 52, thereby closing and sealing through hole 25, as shown in FIG. 15.

[0048] In the manufacturing method of the physical quantity sensor 10 of this embodiment, after bonding the sensor element 30 and the lid 21 to the substrate 11, a coupling agent of an organic silicon compound G is inserted through the through hole 25 to form an anti-stiction layer 53 on the surface of the movable body 33, the surface of the inner bottom surface 15 of the recess 14 provided in the substrate 11, and the surface of the inner bottom surface 23 of the recess 22 provided in the lid 21, so that it is possible to reduce the occurrence of stiction caused by contact between the substrate 11 or the lid 21 and the movable body 33. That is, the sensor element 30 and the outer peripheral space covering it can all be surrounded by a hydrophobic material. Therefore, it is possible to reduce the stiction phenomenon caused by repeated collisions with a certain energy.

[0049] In addition, before sealing the through-hole 25, the anti-stiction layer 53 formed on the surface of the fixed electrodes 37, 38, 39 made of a precious metal such as Au, Pt, Pd, Rh, Ir, Ru, Os, Ag, etc., provided on the substrate 11 is removed by heating, so that no unnecessary capacitance is generated between the movable electrodes 34, 35, 36 of the movable body 33 and the fixed electrodes 37, 38, 39. This makes it possible to reduce deterioration in the detection accuracy of acceleration.

[0050] 2. Second embodiment Next, a physical quantity sensor 10a according to a second embodiment will be described with reference to Fig. 16, Fig. 17, and Fig. 18. For convenience of description, Fig. 16 illustrates a state in which the lid 21 is removed, and omits the illustration of the anti-stiction layer 53 provided inside the physical quantity sensor 10a. Also, in Fig. 16, Fig. 17, and Fig. 18, the illustration of wiring provided on the substrate 11a is omitted.

[0051] The physical quantity sensor 10a of this embodiment is similar to the physical quantity sensor 10 of the first embodiment, except that the structure of the fixing part 13a provided on the substrate 11a and the structure of the sensor element 30a are different from those of the physical quantity sensor 10 of the first embodiment. Note that the following description will focus on the differences from the first embodiment described above, and descriptions of similar points will be omitted.

[0052] 16 and 18, the substrate 11a of the physical quantity sensor 10a has an extension in the X direction and the Y direction, and a thickness in the Z direction. As shown in FIG. 17, the substrate 11a has a recess 14 that is recessed downward, and has three fixing parts 13a that protrude from an inner bottom surface 15 of the recess 14 toward the sensor element 30a, and the sensor element 30a is joined onto the fixing parts 13a. In addition, a fixed electrode 47 that surrounds the three fixing parts 13a is disposed on the inner bottom surface 15 of the recess 14 of the substrate 11a at a position that overlaps with the sensor element 30a in a plan view from the Z direction.

[0053] The substrate 11a is joined to a lid 21 having a recess 22, inside which an internal space S for accommodating the sensor element 30a is formed.

[0054] 16, the sensor element 30a has three holding parts 41 aligned in the X direction and respectively joined onto three fixing parts 13a provided on the substrate 11a, and two connecting parts 42 aligned in the Y direction with the holding parts 41 in between, and the three holding parts 41 are disposed between the two connecting parts 42, and the central holding part 41 is connected to the connecting part 42. In addition, the distance between the connecting part 42 located on the positive side of the Y direction and the holding parts 41 is longer than the distance between the connecting part 42 located on the negative side of the Y direction and the holding parts 41.

[0055] The two connecting parts 42 are connected to a movable body 43 that surrounds the two connecting parts 42 and the three holding parts 41 on the side opposite to the holding part 41 side. The movable body 43 has a plurality of movable electrodes 44 that extend respectively on the positive and negative sides of the X direction between the connecting part 42 located on the positive side of the Y direction and the holding part 41. Note that the connecting part 42 is elastically deformable in the Y direction like a spring, so that the movable body 43 is displaceable in the Y direction.

[0056] The two holding parts 41 located on the positive and negative sides in the X direction of the central holding part 41 each have a fixed beam 45 extending diagonally in the Y direction, and a plurality of fixed electrodes 46 extending respectively to the positive and negative sides in the X direction from the fixed beam 45. The plurality of fixed electrodes 46 are disposed on the positive or negative side in the Y direction of the movable electrode 44, and are arranged in a comb shape that meshes with the corresponding movable electrode 44 at intervals.

[0057] When acceleration in the Y direction is applied to such a sensor element 30a, the movable body 43 is displaced in the Y direction based on the magnitude of the acceleration. This displacement causes a change in the capacitance value of the electrostatic capacitance between the movable electrode 44 and the fixed electrode 46. Therefore, the physical quantity sensor 10a can detect acceleration in the Y direction based on the difference in the capacitance value of the electrostatic capacitance. Note that by arranging the physical quantity sensor 10a or the sensor element 30a in a state rotated 90° in a plan view, it is possible to detect acceleration in the X direction.

[0058] The physical quantity sensor 10a of this embodiment is composed of a substrate 11a and a lid 21, and in the internal space S accommodating the sensor element 30a, as shown in Figs. 17 and 18, an anti-stiction layer 53 is provided on the inner bottom surface 15 and inner side wall of the recess 14 provided in the substrate 11a, the side wall of the fixed part 13a provided in the substrate 11a, the inner bottom surface 23 and inner side wall which are the surfaces of the recess 22 provided in the lid 21 on the movable body 43 side, and the surface excluding the joint surface with the fixed part 13a of the sensor element 30a. However, the anti-stiction layer 53 is not selectively provided on the surface of the fixed electrode 47. Moreover, the anti-stiction layer 53 is not provided on the joint part 50a between the substrate 11a and the lid 21.

[0059] With this configuration, it is possible to reduce stiction caused by contact between the movable body 43 and the lid body 21 due to excessive acceleration in the Y direction or impact from the Z direction. In addition, since the anti-stiction layer 53 is provided on the surface of the movable electrode 44 and the surface of the fixed electrode 46, it is possible to reduce stiction between the movable electrode 44 and the fixed electrode 46 due to excessive acceleration in the Y direction.

[0060] 3. Third embodiment Next, a physical quantity sensor 10b according to a third embodiment will be described with reference to Fig. 19, Fig. 20, and Fig. 21. For convenience of description, Fig. 19 illustrates a state in which the lid body 21 is removed, and omits the illustration of the anti-stiction layer 53 provided inside the physical quantity sensor 10b. Also, in Fig. 19, Fig. 20, and Fig. 21, the illustration of wiring provided on the substrate 11b is omitted.

[0061] A physical quantity sensor 10b of this embodiment is similar to the physical quantity sensor 10 of the first embodiment, except that the structures of fixed parts 101, 102, and 103 provided on a substrate 11b and the structure of a sensor element 30b are different and the sensor element 30b is an angular velocity sensor element that detects an angular velocity around the Z axis. Note that the following description will focus on the differences from the first embodiment described above, and a description of similar points will be omitted.

[0062] 19 and 21, the substrate 11b of the physical quantity sensor 10b has an extension in the X-direction and the Y-direction, and a thickness in the Z-direction. As shown in FIG. 20, the substrate 11b has a recess 14 recessed downward, and has a plurality of fixed parts 101, 102, and 103 protruding from an inner bottom surface 15 of the recess 14 toward the sensor element 30b, and the sensor element 30b is joined onto the fixed parts 101, 102, and 103. In addition, a fixed electrode 160 surrounding the fixed parts 101, 102, and 103 is disposed on the inner bottom surface 15 of the recess 14 of the substrate 11b at a position overlapping with the sensor element 30b in a plan view from the Z direction.

[0063] The substrate 11b is joined to a lid 21 having a recess 22, and an internal space S for accommodating the sensor element 30b is formed inside the lid 21. The internal space S is maintained in a vacuum state.

[0064] As shown in FIG. 19, the sensor element 30b includes a movable body 104, a driving fixed electrode 130, a detection fixed electrode 140, and a holding portion 150.

[0065] The movable body 104 is supported by a holding portion 150 fixed on a fixed portion 103 provided on the substrate 11b, and is disposed at a distance from the substrate 11b. The movable body 104 has a first movable body 106 and a second movable body 108. The first movable body 106 and the second movable body 108 are connected to each other along the X-axis.

[0066] The first movable body 106 and the second movable body 108 have shapes that are symmetrical with respect to a boundary line T1 between them. The boundary line T1 is a straight line along the Y axis. The configuration of the first movable body 106 will be described, and a description of the configuration of the second movable body 108 will be omitted.

[0067] The first movable body 106 has a driving section 110 and a detection section 120. The driving section 110 has a driving support section 112, a driving spring section 114, and a driving movable electrode 116.

[0068] The drive support part 112 has, for example, a frame-like shape, and the detection part 120 is disposed inside the drive support part 112. The drive support part 112 is composed of a first extension part 112a extending in the X direction and a second extension part 112b extending in the Y direction.

[0069] The driving spring portion 114 is disposed on the outside of the driving support portion 112. One end of the driving spring portion 114 is connected to the vicinity of a corner of the driving support portion 112. The corner of the driving support portion 112 is a connection portion between the first extension portion 112a and the second extension portion 112b. The other end of the driving spring portion 114 is connected to the holding portion 150.

[0070] The first movable body 106 is provided with four drive spring portions 114. The first movable body 106 is supported by four holding portions 150.

[0071] The driving spring portion 114 has a shape that extends in the X direction while reciprocating in the Y direction. The multiple driving spring portions 114 are provided symmetrically with respect to a virtual line (not shown) along the X axis that passes through the center of the driving support portion 112, and a virtual line (not shown) along the Y axis that passes through the center of the driving support portion 112. By giving the driving spring portion 114 the shape described above, the driving spring portion 114 is prevented from being deformed in the Y direction and the Z direction, and the driving spring portion 114 can be smoothly expanded and contracted in the X direction, which is the vibration direction of the driving portion 110. Then, the driving support portion 112 can be vibrated in the X direction in accordance with the expansion and contraction of the driving spring portion 114.

[0072] The movable electrode for driving 116 is disposed outside the support portion for driving 112 and is connected to the first extending portion 112 a of the support portion for driving 112 .

[0073] The driving fixed electrode 130 is disposed outside the driving support portion 112. A part of the driving fixed electrode 130 is fixed on the fixed portion 101 provided on the substrate 11b. A plurality of driving fixed electrodes 130 are provided and disposed opposite the driving movable electrode 116. The driving fixed electrode 130 has a comb-like shape. The driving movable electrode 116 has a protrusion 116a that can be inserted between the comb teeth of the driving fixed electrode 130. By reducing the distance between the driving fixed electrode 130 and the protrusion 116a, the electrostatic force acting between the driving fixed electrode 130 and the driving movable electrode 116 can be increased.

[0074] When a voltage is applied to the driving fixed electrode 130 and the driving movable electrode 116, an electrostatic force can be generated between the driving fixed electrode 130 and the driving movable electrode 116. This causes the driving spring portion 114 to expand and contract in the X direction, and the driving support portion 112 of the driving portion 110 can be vibrated in the X direction.

[0075] The detection unit 120 is connected to the driving unit 110. In the illustrated example, the detection unit 120 is disposed inside the driving support unit 112. The detection unit 120 has a detection support unit 122, a detection spring unit 124, and a detection movable electrode 126.

[0076] The detection support portion 122 has, for example, a frame-like shape. In the illustrated example, the detection support portion 122 is configured by a third extension portion 122a extending in the X direction and a fourth extension portion 122b extending in the Y direction.

[0077] The detection spring portion 124 is disposed outside the detection support portion 122. The detection spring portion 124 connects the detection support portion 122 and the drive support portion 112. More specifically, one end of the detection spring portion 124 is connected to the vicinity of a corner of the detection support portion 122. The corner of the detection support portion 122 is a connection portion between the third extension portion 122a and the fourth extension portion 122b. The other end of the detection spring portion 124 is connected to the first extension portion 112a of the drive support portion 112.

[0078] The detection spring portion 124 has a shape that reciprocates in the X direction and extends in the Y direction. In the illustrated example, four detection spring portions 124 are provided in the first movable body 106. The detection spring portions 124 are provided symmetrically with respect to a virtual line (not shown) along the X axis passing through the center of the detection support portion 122 and a virtual line (not shown) along the Y axis passing through the center of the detection support portion 122. By forming the detection spring portion 124 in the above-described shape, it is possible to suppress the detection spring portion 124 from being deformed in the X direction and the Z direction, and to allow the detection spring portion 124 to smoothly expand and contract in the Y direction, which is the vibration direction of the detection portion 120. Then, the detection support portion 122 of the detection portion 120 can be vibrated in the Y direction in accordance with the expansion and contraction of the detection spring portion 124.

[0079] The detection movable electrode 126 is arranged on the inner side of the detection support portion 122 and connected to the detection support portion 122. In the illustrated example, the detection movable electrode 126 extends in the X direction and is connected to two fourth extension portions 122b of the detection support portion 122.

[0080] The detection fixed electrode 140 is disposed inside the detection support portion 122. A part of the detection fixed electrode 140 is fixed on a fixing portion 102 provided on the substrate 11b. In the illustrated example, a plurality of detection fixed electrodes 140 are provided and are disposed opposite each other with the detection movable electrode 126 interposed therebetween.

[0081] The number and shapes of the detection movable electrodes 126 and the detection fixed electrodes 140 are not particularly limited as long as a change in the electrostatic capacitance between the detection movable electrodes 126 and the detection fixed electrodes 140 can be detected.

[0082] Next, the operation of the sensor element 30b that detects the angular velocity around the Z axis will be described. When a voltage is applied to the driving fixed electrode 130 and the driving movable electrode 116, an electrostatic force can be generated between the driving fixed electrode 130 and the driving movable electrode 116. This allows the driving spring portion 114 to expand and contract in the X direction, and the driving portion 110 to vibrate in the X direction. Since the detection portion 120 is connected to the driving portion 110, the detection portion 120 also vibrates in the X direction in association with the vibration of the driving portion 110. Furthermore, the first movable body 106 and the second movable body 108 vibrate in the X direction in opposite phases to each other and at a predetermined frequency.

[0083] When an angular velocity ω about the Z axis is applied to the sensor element 30b in a state in which the first movable body 106 and the second movable body 108 are vibrating in the X direction in opposite phases to each other, the Coriolis force acts, and the detection unit 120 is displaced in the Y direction. For example, when the detection unit 120 of the first movable body 106 is displaced in the positive Y direction, the detection unit 120 of the second movable body 108 is displaced in the negative Y direction. That is, the detection unit 120 of the first movable body 106 and the detection unit 120 of the second movable body 108 are displaced in opposite directions to each other due to the Coriolis force. The detection unit 120 of the first movable body 106 and the detection unit 120 of the second movable body 108 repeat this operation while receiving the Coriolis force.

[0084] As the detection unit 120 is displaced in the Y direction, the distance between the detection movable electrode 126 and the detection fixed electrode 140 changes, and the electrostatic capacitance between the detection movable electrode 126 and the detection fixed electrode 140 changes. In the sensor element 30b, by applying a voltage to the detection movable electrode 126 and the detection fixed electrode 140, the amount of change in the electrostatic capacitance between the detection movable electrode 126 and the detection fixed electrode 140 can be detected and the angular velocity around the Z axis can be obtained.

[0085] The physical quantity sensor 10b of this embodiment is composed of a substrate 11b and a lid 21, and in the internal space S accommodating the sensor element 30b, as shown in Figs. 20 and 21, an anti-stiction layer 53 is provided on the inner bottom surface 15 and inner side wall of the recess 14 provided in the substrate 11b, the side walls of the fixed parts 101, 102, and 103 provided in the substrate 11b, the inner bottom surface 23 and inner side wall which are the surfaces of the recess 22 provided in the lid 21 on the movable body 43 side, and the surfaces of the sensor element 30b except the bonding surfaces with the fixed parts 101, 102, and 103, as shown in Figs. 20 and 21. However, the anti-stiction layer 53 is not selectively provided on the surface of the fixed electrode 160. Also, the anti-stiction layer 53 is not provided on the bonding part 50b between the substrate 11b and the lid 21.

[0086] With this configuration, it is possible to reduce stiction caused by contact between the movable body 104 and the lid body 21 due to an excessive angular velocity around the Z axis and impacts from the X, Y, and Z directions. In addition, since the anti-stiction layer 53 is provided on the surfaces of the driving movable electrode 116, the detection movable electrode 126, the driving fixed electrode 130, and the detection fixed electrode 140, it is possible to reduce stiction between the driving movable electrode 116 and the driving fixed electrode 130 and between the detection movable electrode 126 and the detection fixed electrode 140 due to impacts from the X and Y directions.

[0087] 4. Fourth embodiment Next, a physical quantity sensor 10c according to a fourth embodiment will be described with reference to Fig. 22. Note that in Fig. 22, wiring provided on the substrate 11c and the fixed substrate 201 is omitted from illustration.

[0088] A physical quantity sensor 10c of this embodiment is similar to the physical quantity sensor 10 of the first embodiment except that a substrate 11c and a lid body 21c have different structures and have two sensor elements 30c1 and 30c2 compared to the physical quantity sensor 10 of the first embodiment. Note that the following description will focus on the differences from the first embodiment described above, and descriptions of similar points will be omitted.

[0089] As shown in FIG. 22, the physical quantity sensor 10c has a flat substrate 11c, a fixed substrate 201 having two through-holes 220, an element substrate 202 on which a sensor element 30c1 for detecting acceleration and a sensor element 30c2 for detecting angular velocity are formed, and a lid body 21c joined with a glass frit 51.

[0090] The substrate 11c is a silicon substrate, and two fixed electrodes 210 made of a precious metal such as Au, Pt, Pd, Rh, Ir, Ru, Os, or Ag are disposed at positions facing the two sensor elements 30c1 and 30c2, respectively, at the positions of the two through-holes 220 of the fixed substrate 201. In addition, the fixed substrate 201 made of a glass material containing alkali metal ions is bonded onto the substrate 11c by anodic bonding or the like.

[0091] The fixed substrate 201 has through-holes 220 arranged at a position facing the movable body 301 of the sensor element 30c1 and at a position facing the movable body 302 of the sensor element 30c2. In addition, an element substrate 202 made of a silicon substrate on which the two sensor elements 30c1 and 30c2 are formed is bonded onto the fixed substrate 201 by anodic bonding or the like.

[0092] The holders 303 of the sensor elements 30c1 and 30c2 of the element substrate 202 and a frame 304 surrounding the two sensor elements 30c1 and 30c2 are joined to the fixed substrate 201. The frame 304 surrounding the two sensor elements 30c1 and 30c2 is joined to the lid 21c by a glass frit 51.

[0093] Therefore, by stacking and joining the substrate 11c, the fixed substrate 201, the element substrate 202, and the cover 21c, an internal space S1 accommodating the sensor element 30c1 and an internal space S2 accommodating the sensor element 30c2 can be formed. The internal space S1 of the sensor element 30c1 is sealed in an atmospheric pressure atmosphere, more specifically, 10,000 to 120,000 Pa, and the internal space S2 of the sensor element 30c2 is sealed in a vacuum atmosphere, more specifically, 0.1 to 10 Pa. That is, the internal pressures of the internal spaces S1 and S2 are different.

[0094] The lid 21c has two through holes 25 communicating with the internal space S1 and the internal space S2, respectively, at positions facing the two sensor elements 30c1 and 30c2. A metal layer 26 made of a precious metal such as Au, Pt, Pd, Rh, Ir, Ru, Os, or Ag is provided on the side surface of the through hole 25, and the through hole 25 is closed and sealed by a sealing member 52 in contact with the metal layer 26.

[0095] Except for the surfaces of the fixed electrode 210, the metal layer 26, and the sealing member 52 in the internal space S1 and the internal space S2, an anti-stiction layer 53 is provided on the surfaces of the substrate 11c, the fixed substrate 201, the element substrate 202, and the lid body 21c that contact the internal space S1 and the internal space S2.

[0096] With this configuration, it is possible to reduce stiction caused by contact between the movable bodies 301, 302 and the lid body 21c and between the movable bodies 301, 302 and the holding portion 303 in the event of excessive acceleration or angular velocity, or impacts from the X, Y, and Z directions.

[0097] 5. Fifth embodiment Next, an inertial measurement unit 2000 including the physical quantity sensors 10 to 10c according to the fifth embodiment will be described with reference to Fig. 23 and Fig. 24. In the following description, a configuration to which the physical quantity sensor 10 is applied will be described as an example.

[0098] 23 is a device that detects inertial momentum such as the attitude and behavior of a moving body such as an automobile or a robot. The inertial measurement unit 2000 functions as a so-called six-axis motion sensor that includes an acceleration sensor that detects accelerations Ax, Ay, and Az in directions along three axes, and an angular velocity sensor that detects angular velocities ωx, ωy, and ωz about the three axes.

[0099] The inertial measurement unit 2000 is a rectangular parallelepiped with a substantially square planar shape. Moreover, screw holes 2110 are formed as fixing parts near two vertices located in the diagonal direction of the square. The inertial measurement unit 2000 can be fixed to a mounting surface of a mounting body such as an automobile by passing two screws through the two screw holes 2110. Note that by selecting parts and modifying the design, it is possible to reduce the size to a size that can be mounted on a smartphone or digital camera, for example.

[0100] The inertial measurement device 2000 has an outer case 2100, a joint member 2200, and a sensor module 2300, and is configured such that the sensor module 2300 is inserted inside the outer case 2100 with the joint member 2200 interposed therebetween. The sensor module 2300 also has an inner case 2310 and a substrate 2320.

[0101] The external shape of outer case 2100 is a rectangular parallelepiped with a substantially square planar shape, similar to the overall shape of inertial measurement unit 2000, and screw holes 2110 are formed near each of two vertices located diagonally in the square. Outer case 2100 is also box-shaped, and contains sensor module 2300 therein.

[0102] The inner case 2310 is a member that supports the substrate 2320, and is shaped to fit inside the outer case 2100. The inner case 2310 is formed with a recess 2311 for preventing contact with the substrate 2320 and an opening 2312 for exposing a connector 2330, which will be described later. The inner case 2310 is joined to the outer case 2100 via a joining member 2200. The substrate 2320 is joined to the bottom surface of the inner case 2310 via an adhesive.

[0103] 24, a connector 2330, an angular velocity sensor 2340z that detects an angular velocity around the Z axis, an acceleration sensor unit 2350 that detects acceleration in the directions of the X axis, the Y axis, and the Z axis, and the like are mounted on the substrate 2320. In addition, an angular velocity sensor 2340x that detects an angular velocity around the X axis and an angular velocity sensor 2340y that detects an angular velocity around the Y axis are mounted on the side surface of the substrate 2320.

[0104] The acceleration sensor unit 2350 includes at least the physical quantity sensor 10 for measuring the acceleration in the Z direction described above, and can detect acceleration in one axis direction, or in two or three axes directions as necessary. The angular velocity sensors 2340x, 2340y, and 2340z are not particularly limited, and for example, a vibration gyro sensor using the Coriolis force can be used.

[0105] In addition, a control IC 2360 is mounted on the lower surface of the substrate 2320. The control IC 2360, which serves as a control unit that performs control based on the detection signal output from the physical quantity sensor 10, is an MCU (Micro Controller Unit), and has a built-in storage unit including a non-volatile memory, an A / D converter, and the like, and controls each unit of the inertial measurement unit 2000. The storage unit stores a program that specifies the order and content for detecting acceleration and angular velocity, a program that digitizes the detection data and incorporates it into packet data, associated data, and the like. Note that a plurality of other electronic components are also mounted on the substrate 2320.

[0106] Since such an inertial measurement unit 2000 uses an acceleration sensor unit 2350 including a physical quantity sensor 10, an inertial measurement unit 2000 that has excellent shock resistance and high reliability can be obtained. [Explanation of symbols]

[0107] 10, 10a, 10b, 10c...physical quantity sensor, 11...substrate, 12...upper surface, 13...fixed portion, 14...recess, 15...inner bottom surface, 16...connection terminal, 21...cover, 22...recess, 23...inner bottom surface, 24...upper surface, 25...through hole, 26...metal layer, 30...sensor element, 31...holding portion, 32...support beam, 33...movable body, 34...first movable electrode, 35...second movable electrode, 36...third movable electrode, 37...first fixed electrode, 38...second fixed electrode, 39...third fixed electrode, 50...joint, 52...sealing member, 53...anti-stiction layer, 55...substrate for sensor element, 56...recess, 2000...inertial measurement unit, G...organic silicon compound, J1...rotating axis, L...laser light, S...internal space.

Claims

1. A substrate; a movable body fixed to a fixing portion provided on the substrate and displaceable in a predetermined direction; A movable electrode provided on the movable body; A fixed electrode having a surface made of a metal, an alloy of the metal, or a nitride is provided on the substrate. With poles, a cover that houses the movable body together with the substrate; An anti-stiction layer; a metal layer provided on a side surface of a through hole penetrating the lid in a thickness direction; a sealing member that is in contact with the metal layer and closes the through hole; Equipped with The anti-stiction layer is provided on a surface of the cover body on the movable body side, and the fixed and between the metal layer and the sealing member. , which are located Physical quantity sensor.

2. The anti-stiction layer is not provided at the joint between the lid and the substrate. are located in The physical quantity sensor according to claim 1 .

3. a movable body fixed to a fixing portion provided on a substrate and displaceable in a predetermined direction; a movable electrode provided on the movable body; and a metal, an alloy of the metal, or forming a fixed electrode having a surface made of a nitride; preparing a lid having a through hole; a step of joining the lid body to the substrate and housing the movable body between the lid body and the substrate; With Anti-sticking is applied to the surfaces of the lid, the movable body, and the substrate through the through hole. forming a coating layer; The lid, the movable body, and the substrate are heated to remove the anti-sticking agent from the fixed electrode. removing the coating layer; blocking the through hole; having A method for manufacturing a physical quantity sensor.

4. The metal is a noble metal. The method for manufacturing the physical quantity sensor according to claim 3 .

5. The step of preparing the lid further includes a step of forming a metal layer on a side surface of the through hole. Have The method for manufacturing the physical quantity sensor according to claim 3 or 4.

6. The metal layer is a noble metal. A method for manufacturing the physical quantity sensor according to claim 5 .

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