Vibration element, method for adjusting frequency of vibration element, method for manufacturing vibration element, physical quantity sensor, inertial measurement device, electronic device, and moving object

Abstract

The present application provides a vibration element, a frequency adjustment method and a manufacturing method thereof, a physical quantity sensor, an inertial measurement device, an electronic device, and a moving body. The frequency adjustment method of the vibration element is characterized in that the vibration element has a vibration arm having a first main surface and a second main surface in a positive and negative relationship with each other, and the frequency adjustment method of the vibration element has a process of adjusting the resonance frequency of the vibration element by removing a portion of the first main surface side of the vibration arm by irradiating the vibration element with an energy ray, the activation amount of the second main surface side of the vibration arm being activated by the energy ray being smaller than the activation amount of the first main surface side of the vibration arm being activated by the energy ray.

Description

[0001] This application is a divisional application of the invention patent application entitled "Vibration element and frequency adjustment method and manufacturing method thereof, physical quantity sensor, inertial measurement device, electronic device and moving body", filed on March 28, 2019, with application number 201910243170.5. Technical Field

[0002] This invention relates to a method for adjusting the frequency of a vibration element, a method for manufacturing a vibration element, a vibration element, a physical quantity sensor, an inertial measurement device, an electronic device, and a moving body. Background Technology

[0003] Previously, it was known that there were physical quantity detection devices that used vibrating elements such as piezoelectric oscillators and MEMS (Micro Electro Mechanical Systems) oscillators to detect physical quantities such as angular velocity and acceleration.

[0004] As an example of such a physical quantity detection device, Patent Document 1 discloses a vibration-type gyroscope having a piezoelectric vibrator with: a base; a connecting arm extending from the base; a plurality of drive arms extending from the ends of the connecting arm; and a plurality of detection arms extending from the base. When this vibration-type gyroscope is subjected to an angular velocity in a predetermined direction while the drive arms are vibrating in a bending motion, a Coriolis force is applied to the drive arms, which in turn causes the detection arms to vibrate in a bending motion. By detecting the bending vibration of these detection arms, the angular velocity can be detected.

[0005] Furthermore, in the vibration-type gyroscope described in Patent Document 1, a weighting layer made of metal is provided at the end of each drive arm. Moreover, in order to reduce vibration leakage from the drive arm to the base caused by the imbalance of the drive arm's resonant frequency, the mass of the drive arm is adjusted by removing the weighting layer at the end of each drive arm.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2006-105614

[0007] In the mass adjustment of the drive arm described in Patent Document 1, a portion of the weighting layer is removed by irradiating it with a laser, thereby adjusting the mass of the weighting layer. When the weighting layer is irradiated with a laser, the irradiated area is activated, making it prone to the adhesion of foreign matter such as organic matter. As a result, there is a problem that the vibration balance of the adjusted drive arm deviates over time.

[0008] Furthermore, when adjusting the mass of the weighting layer on one main surface of the drive arm, unexpected mass changes sometimes occur in the weighting layer on the other main surface, which is not directly exposed to the laser. Because these mass changes are unexpected, the vibration balance of the vibrating arm deviates over time. Moreover, when the vibration balance deviates, vibration leakage is likely to occur. Summary of the Invention

[0009] This invention was made to solve the above-mentioned problems and can be implemented as the following application examples.

[0010] In the frequency adjustment method of the vibration element in this application example, the vibration element has a base and a vibration arm, the vibration arm extends from the base and has a first main surface and a second main surface that are opposite to each other, and the frequency adjustment method of the vibration element has the following steps: by irradiating the vibration element with an energy line, a portion of the first main surface side of the vibration arm is removed, thereby adjusting the resonant frequency of the vibration element, wherein the activation amount of the second main surface side of the vibration arm activated by the energy line is smaller than the activation amount of the first main surface side of the vibration arm activated by the energy line.

[0011] In the frequency adjustment method of the vibration element in the above application example, the vibration arm has: an arm portion located on the base side; a weighting portion located on the end side of the arm portion; and a frequency adjustment film disposed on the first main surface side of the weighting portion, wherein at least a portion of the frequency adjustment film is irradiated with the energy line.

[0012] In the frequency adjustment method of the vibration element in the above application example, the frequency adjustment film contains a metallic material, and the vibration arm on the second main surface side of the weighting part contains an oxide material.

[0013] In the frequency adjustment method of the vibration element in the above application example, the vibration element has a pair of vibration arms that extend from the base in the same direction as each other.

[0014] In the frequency adjustment method of the vibration element in the above application example, when viewed in a plane from the thickness direction of the base, the area of ​​the region irradiating the energy line to one of the vibration arms is the same as the area of ​​the region irradiating the energy line to the other vibration arm.

[0015] The manufacturing method of the vibration element in this application example includes the frequency adjustment method of the vibration element in the above application example.

[0016] The vibrating element in this application example has:

[0017] base; and

[0018] A vibrating arm, extending from the base, has a first principal surface and a second principal surface that are opposite to each other.

[0019] The activation level of the second principal surface side of the vibrating arm when irradiated with the energy line is smaller than the activation level of the first principal surface side of the vibrating arm when irradiated with the energy line.

[0020] The physical quantity sensor in this application example has:

[0021] The vibrating element in the above application example; and

[0022] The package contains the vibrating element.

[0023] The inertial measurement device in this application example has:

[0024] The physical quantity sensor in the above application example; and

[0025] The circuit is electrically connected to the physical quantity sensor.

[0026] The electronic device in this application example is characterized by having:

[0027] The vibrating element in the above application example; and

[0028] The circuit outputs a drive signal to the vibrating element.

[0029] The moving body in this application example is characterized by having:

[0030] The vibrating element in the above application example; and

[0031] The main body is equipped with a physical quantity sensor having the aforementioned vibration element. Attached Figure Description

[0032] Figure 1 This is a cross-sectional view showing a physical quantity sensor with a vibration element having an embodiment.

[0033] Figure 2 It is a plan view of the vibrating element.

[0034] Figure 3 It is a plan view of the vibrating element, used to explain the operation of the vibrating element.

[0035] Figure 4 yes Figure 3 Sectional view along line A1-A1 in the diagram.

[0036] Figure 5 This is a flowchart illustrating an example of a method for manufacturing a vibrating element.

[0037] Figure 6It is a top view of the vibrating element obtained through the vibrating element forming process.

[0038] Figure 7 It is a bottom view of the vibrating element obtained through the vibrating element forming process.

[0039] Figure 8 This is a top view of the vibrating element in the frequency adjustment process.

[0040] Figure 9 This is a plan view of the vibrating element in the sealing process.

[0041] Figure 10 This is an exploded perspective view showing an embodiment of the inertial measurement device of the present invention.

[0042] Figure 11 yes Figure 10 A three-dimensional view of the substrate of the inertial measurement device shown.

[0043] Figure 12 This is a perspective view illustrating an embodiment of the electronic device of the present invention (mobile personal computer).

[0044] Figure 13 This is a top view illustrating an embodiment of the electronic device (mobile phone) of the present invention.

[0045] Figure 14 This is a perspective view illustrating an embodiment of the electronic device of the present invention (digital still camera).

[0046] Figure 15 This is a perspective view showing an embodiment (automobile) of the mobile body of the present invention.

[0047] Label Explanation

[0048] 1: Vibrating element; 1a: Vibrating element; 4: Vibrating body; 5: Weighted film pattern; 5a: Weighted film pattern; 10: Physical quantity sensor; 11: Package; 12: Support substrate; 13: Wiring pattern; 14: Circuit element; 15: Conductive line; 16: Adhesive; 17: Conductive adhesive; 40: Electrode film pattern; 41: Base; 42: Connecting arm; 43: Connecting arm; 44: Driving vibrating arm; 45: Driving vibrating arm; 46: Driving vibrating arm; 47: Driving vibrating arm; 48: Detection vibrating arm; 49: Detection vibrating arm; 51: Weighted film; 51a: Weighted film; 52: Weighted film; 52a: Weighted film; 53: Weighted film; 53a: Weighted film; 54: Weighted film; 54a 55: Weighting membrane; 56: Weighting membrane; 111: Base; 112: Cover; 113: Joining component; 115: Through hole; 116: Seal; 401: Drive signal electrode; 402: Drive ground electrode; 403: Detection signal electrode; 404: Detection signal electrode; 410: Base body; 440: Arm; 441: Weighting part; 450: Arm; 451: Weighting part; 460: Arm; 461: Weighting part; 470: Arm; 471: Weighting part; 480: Arm; 481: Weighting part; 490: Arm; 491: Weighting part; 511: Recess; 521: Recess; 531: Recess; 541: Recess; 1100: Personal computer; 110 2: Keyboard; 1104: Main body; 1106: Display unit; 1108: Display section; 1200: Mobile phone; 1202: Operation buttons; 1204: Answering port; 1206: Talking port; 1208: Display section; 1300: Digital still camera; 1302: Housing; 1304: Light receiving unit; 1306: Shutter button; 1308: Memory; 1310: Display section; 1500: Automobile; 1501: Vehicle body; 1502: Vehicle body attitude control device; 1503: Wheel; 2000: Inertial measurement unit; 2100: Housing; 2110: Threaded hole; 2200: Connecting component; 2300: Sensor module; 2310: Inner housing; 2311: Recess ; 2312: Opening; 2320: Substrate; 2330: Connector; 2340X: Angular velocity sensor; 2340Y: Angular velocity sensor; 2340Z: Angular velocity sensor; 2350: Accelerometer; 2360: Control IC; 4411: First main surface; 4412: Second main surface; 4511: First main surface; 4512: Second main surface; 4611: First main surface; 4612: Second main surface; 4711: First main surface; 4712: Second main surface; A: Line segment; E: Energy line; M: Matter; S: Space; S51: Region; S52: Region; S53: Region; S54: Region; a: Axis; α: Arrow; β: Arrow; γ: Arrow; ω: Angular velocity. Detailed Implementation

[0049] Hereinafter, preferred embodiments of the vibration element frequency adjustment method, vibration element manufacturing method, vibration element, physical quantity sensor, inertial measurement device, electronic device, and moving body will be described in detail based on the accompanying drawings. Furthermore, to make the parts to be described recognizable, some parts are shown in appropriate enlargements or reductions, and some parts are shown schematically.

[0050] 1. Physical quantity sensor

[0051] First, before describing the frequency adjustment method and manufacturing method of the vibration element according to the embodiments, a physical quantity sensor having the vibration element according to the embodiments will be briefly described.

[0052] Figure 1 This is a cross-sectional view showing a physical quantity sensor with a vibration element having an embodiment.

[0053] Figure 1 The physical quantity sensor 10 shown has: a vibration element 1; a package 11 that houses the vibration element 1; a support substrate 12 and a wiring pattern 13 that support the vibration element 1 in the package 11; and a circuit element 14 disposed within the package 11.

[0054] The package 11 includes: a box-shaped base 111 having a recess for housing the vibrating element 1; and a plate-shaped cover 112, which is engaged with the base 111 via a coupling member 113 to close the opening of the recess of the base 111. The space S, which is the enclosed space within the package 11, can be in a depressurized state or a vacuum state, or it can be filled with an inert gas such as nitrogen, helium, or argon. Furthermore, a through hole 115, serving as a sealing hole, is provided at the bottom of the base 111, and the through hole 115 is sealed, for example, by a sealing member 116 formed using various glass or metal materials. Alternatively, a portion of the cover 112 of the package 11 can be concave, and after the cover 112 is engaged with the seam ring, it can be sealed by irradiating the concave portion of the cover with a laser.

[0055] The recess of the base 111 has an upper stepped surface on the opening side, a lower stepped surface on the bottom side, and a middle stepped surface between these surfaces. The material of the base 111 is not particularly limited, but various ceramics such as alumina and various glass materials can be used. Similarly, the material of the cover 112 is not particularly limited, but a material with a coefficient of thermal expansion similar to that of the base 111 is preferred. For example, if the base 111 is made of a ceramic as described above, an alloy such as Kovar is preferred. Furthermore, in this embodiment, a seam ring is used as the joining member 113, but the joining member 113 can also be constructed using, for example, low-melting-point glass, adhesives, etc.

[0056] Multiple connection terminals (not shown) are respectively provided on the upper and middle surfaces of the recess in the base 111. A portion of the multiple connection terminals provided on the middle surface are electrically connected to terminals (not shown) provided on the bottom surface of the base 111 via a wiring layer (not shown) provided on the base 111, and the remaining portion are electrically connected to multiple connection terminals provided on the upper surface via wiring (not shown). These connection terminals are not particularly limited as long as they are conductive, and for example, they can be made of metal coatings, which are formed by stacking Ni (nickel), Au (gold), Ag (silver), Cu (copper), etc., on a base layer of metallized layers such as Cr (chromium) and W (tungsten).

[0057] The circuit element 14 is fixed to the lower stepped surface of the recess in the base 111 by an adhesive 16 or the like. For example, epoxy, silicone, or polyimide adhesives can be used as the adhesive 16. The circuit element 14 has a plurality of terminals (not shown), each of which is electrically connected to a connection terminal provided on the intermediate stepped surface via a conductive line 15. The circuit element 14 includes: a drive circuit for driving the vibration element 1 to vibrate; and a detection circuit for detecting the vibration generated by the vibration element 1 when an angular velocity is applied.

[0058] Furthermore, multiple connection terminals on the upper stepped surface of the recess in the base 111 are connected to the wiring pattern 13 via a conductive adhesive 17. The wiring pattern 13 is bonded to the support substrate 12. As the conductive adhesive 17, for example, conductive adhesives such as epoxy, silicone, or polyimide adhesives mixed with conductive substances such as metal fillers can be used.

[0059] The support substrate 12 has an opening in the center, and a plurality of elongated leads of the wiring pattern 13 extend within the opening. The ends of these leads are connected to the vibrating element 1 via conductive bumps (not shown).

[0060] In addition, in this embodiment, the circuit element 14 is disposed inside the package 11, but the circuit element 14 may also be disposed outside the package 11.

[0061] 2. Vibrating element

[0062] Figure 2 It is a plan view of the vibrating element. Figure 3 It is a plan view of the vibrating element, used to explain the operation of the vibrating element. Figure 4 yes Figure 3 The section view along line A1-A1. Additionally, in... Figure 2 and Figure 3For ease of explanation, the X-axis, Y-axis, and Z-axis are illustrated as three mutually perpendicular axes, with the leading edge of the arrow representing each axis designated as "+" and the base edge as "-". The direction parallel to the X-axis is called the "X-axis direction", the direction parallel to the Y-axis is called the "Y-axis direction", and the direction parallel to the Z-axis is called the "Z-axis direction". The +Z-axis direction side is called "up", and the -Z-axis direction side is called "down". In this embodiment, the X-axis, Y-axis, and Z-axis correspond to the electrical axis, mechanical axis, and optical axis, which are the crystal axes of quartz, respectively.

[0063] Figure 2 and Figure 3 The vibration element 1 shown is a sensor element for detecting the angular velocity ω about the Z-axis. This vibration element 1 has a vibrating body 4 and an electrode film pattern (not shown) and a weighting film pattern 5 formed on the surface of the vibrating body 4. Additionally, in Figure 3 and Figure 4 The diagram of the electrode film pattern is omitted.

[0064] -Vibrating Body-

[0065] The vibrating body 4 extends along the XY plane, which defines the Y-axis (mechanical axis) and X-axis (electric axis) as the crystal axes of the quartz substrate, and is formed into a plate with thickness in the Z-axis (optical axis) direction. That is, the vibrating body 4 is composed of a Z-cut quartz plate. Furthermore, the Z-axis does not necessarily need to be aligned with the thickness direction of the vibrating body 4; from the viewpoint of reducing frequency changes near room temperature due to temperature, it can be slightly tilted relative to the thickness direction. Specifically, a Z-cut quartz plate refers to a quartz plate with a chamfer such that the surface perpendicular to the Z-axis becomes the principal surface after rotating it within a range of 0 degrees to 10 degrees with at least one of the X-axis and Y-axis as its center. Alternatively, the vibrating body 4 can also be made of a non-piezoelectric material such as silicon; in this case, it is sufficient to appropriately provide piezoelectric elements on the vibrating body 4.

[0066] The vibrator 4 in this embodiment has a so-called double-T shape. The vibrator 4 includes: a base body 410; a pair of connecting arms 42 and 43 extending from the base body 410; two driving vibrating arms 44 and 45 extending from the connecting arm 42; two driving vibrating arms 46 and 47 extending from the connecting arm 43; and two detection vibrating arms 48 and 49 extending from the base body 410. Furthermore, the base body 41 is formed by the base body 410 and the pair of connecting arms 42 and 43.

[0067] In addition, the vibrating body 4 is in Figure 2The structure is symmetrical from left to right. In this embodiment, it has: a pair of driving vibration arms 44 and 46, which are parallel to each other and extend in the same direction, i.e., the +Y axis direction, relative to the base 41; and a pair of driving vibration arms 45 and 47, which are parallel to each other and extend in the same direction, i.e., the -Y axis direction, relative to the base 41. That is, in this embodiment, there are two sets of "a pair of vibration arms".

[0068] The base 41 is fixed to the base 111 of the package 11 by means of the support substrate 12 and wiring pattern 13.

[0069] Connecting arms 42 and 43 extend from the base 41 in opposite directions along the X-axis. Alternatively, slots or holes extending along their length direction, i.e., the X-axis, may be provided on the upper and lower surfaces of connecting arms 42 and 43, respectively.

[0070] Driven vibrating arms 44 and 45 extend in opposite directions along the Y-axis from the end of connecting arm 42. Similarly, driven vibrating arms 46 and 47 extend in opposite directions along the Y-axis from the end of connecting arm 43.

[0071] In this embodiment, the drive vibration arms 44, 45, 46, and 47 include: arm portions 440, 450, 460, and 470, which are located on the base 41 side; and weight-applying portions 441, 451, 461, and 471, which are located at their ends, i.e., on the side opposite to the base 41, than the arm portions 440, 450, 460, and 470. The width W1 of the weight-applying portions 441, 451, 461, and 471 is wider than the width W2 of the arm portions 440, 450, 460, and 470. Alternatively, grooves or holes extending in their extending direction may be provided on the upper and lower surfaces of the drive vibration arms 44-47, as described later.

[0072] The vibration arms 48 and 49 extend from the base 41 along the Y-axis in opposite directions.

[0073] In this embodiment, the detection vibration arms 48 and 49 include: arm portions 480 and 490, which are located on the base 41 side; and weight-applying portions 481 and 491, which are located at a position closer to the end of the arm portions 480 and 490 (i.e., on the side opposite to the base 41). The width of the weight-applying portions 481 and 491 is wider than the width of the arm portions 480 and 490. Alternatively, grooves or holes extending in their extending direction may be provided on the upper and lower surfaces of the detection vibration arms 48 and 49, respectively.

[0074] -Electrode film pattern-

[0075] like Figure 2As shown, the electrode film pattern 40 disposed on the surface of the vibrator 4 includes: a drive signal electrode 401 and a drive ground electrode 402, which are disposed on the arm portions 440, 450, 460, and 470 of the drive vibration arms 44 to 47; detection signal electrodes 403 and 404 and a detection ground electrode (not shown), which are disposed on the arm portions 480 and 490 of the detection vibration arms 48 and 49; and a plurality of terminals, which are disposed on the base 41 corresponding to these electrodes.

[0076] The drive signal electrode 401 is an electrode used to excite the drive vibration of the drive arms 44-47. The drive signal electrodes 401 are respectively disposed on the upper and lower surfaces of the arm portion 460 (see reference). Figure 2 The arm 470 has two sides (not shown). Similarly, drive signal electrodes 401 are respectively disposed on the upper and lower surfaces of the arm 470 (see reference). Figure 2 ) and the two sides of the arm 450 (not shown).

[0077] On the other hand, the drive ground electrode 402 has a potential (e.g., ground potential) relative to the drive signal electrode 401 as a reference. The drive ground electrode 402 is respectively provided on two sides (not shown) of the arm 460 and the upper and lower surfaces (see reference 401). Figure 2 Similarly, the drive grounding electrodes 402 are respectively disposed on the two sides (not shown) of the arm 470 and the upper and lower surfaces (see reference). Figure 2 ).

[0078] The detection signal electrode 403 is an electrode used to detect the charge generated by the detection vibration when the detection vibration arm 48 is excited. The detection signal electrode 403 is disposed on the upper and lower surfaces of the arm portion 480 (see reference). Figure 2 ).

[0079] On the other hand, the detection ground electrode (not shown) has a potential (e.g., ground potential) relative to the detection signal electrode 403 as a reference. The detection ground electrode is disposed on both sides of the arm 480 (not shown).

[0080] The detection signal electrode 404 is an electrode used to detect the charge generated by the detection vibration when the detection vibration arm 49 is excited. The detection signal electrode 404 is disposed on the upper and lower surfaces of the arm portion 490 (see reference). Figure 2 ).

[0081] On the other hand, the detection ground electrode (not shown) has a potential (e.g., ground potential) relative to the detection signal electrode 404 as a reference. The detection ground electrode is disposed on both sides of the arm 490 (not shown).

[0082] Alternatively, vibration detection can be performed by detecting the differential signal between the detection signal electrode 403 of the vibrating arm 48 and the detection signal electrode 404 of the vibrating arm 49.

[0083] -Weighted film pattern-

[0084] The weighted film pattern 5 is disposed on the portion of the electrode film pattern 40 located at the ends of the driving vibration arms 44, 45, 46, and 47. For example... Figure 3 As shown, the plurality of weight-applying membrane patterns 5 include: weight-applying membranes 51, 52, 53, and 54, which are disposed on weight-applying portions 441, 451, 461, and 471, located at the ends of the driving vibration arms 44, 45, 46, and 47; and weight-applying membranes 55 and 56, which are disposed on weight-applying portions 481 and 491, located at the ends of the detection vibration arms 48 and 49. Additionally, in Figure 3 The diagram of electrode film pattern 40 is omitted in the text.

[0085] The weighting membranes 51-54 have the function of adjusting the resonant frequency of the driving vibration arms 44-47. The weighting membranes 55 and 56 have the function of adjusting the resonant frequency of the detection vibration arms 48 and 49.

[0086] Figure 3 The weighted membranes 51-54 shown indicate the state after the resonant frequencies of the driving vibrating arms 44-47 have been adjusted, as described later. Therefore, as Figure 3 As shown, portions of the weighting films 51 to 54 are removed. Therefore, the weighting portion 441 has a recess 511 formed by removing a portion of the weighting film 51. Furthermore, the weighting portion 451 has a recess 521 formed by removing a portion of the weighting film 52. Furthermore, the weighting portion 461 has a recess 531 formed by removing a portion of the weighting film 53. Furthermore, the weighting portion 471 has a recess 541 formed by removing a portion of the weighting film 54. By removing portions of the weighting films 51 to 54 in this manner, the resonant frequency of the drive vibrating arms 44 to 47 can be appropriately adjusted, and leakage vibration can be eliminated.

[0087] In addition, the recesses 511, 521, 531 and 541 can be formed as needed. When adjusting the resonant frequency, the formation of at least one or all of the recesses can be omitted.

[0088] The constituent materials of these weighting films 51-56 are not particularly limited; for example, metals, inorganic compounds, resins, etc., can be used, but metals or inorganic compounds are preferred. Metals or inorganic compounds can be easily and precisely formed into films using a vapor-phase film deposition method. Furthermore, the weighting films 51-56 composed of metals or inorganic compounds can be efficiently and precisely removed by irradiation with energy lines. Therefore, by forming the weighting film pattern 5 from metals or inorganic compounds, frequency adjustment, which will be described later, can be performed more efficiently and precisely.

[0089] Examples of suitable metallic materials include, for instance, individual metals such as nickel (Ni), gold (Au), platinum (Pt), aluminum (Al), silver (Ag), chromium (Cr), copper (Cu), molybdenum (Mo), niobium (Nb), tungsten (W), iron (Fe), titanium (Ti), cobalt (Co), zinc (Zn), and zirconium (Zr), or alloys containing at least one of these metals. One or more of these metals can be used in combination. From the viewpoint of being able to simultaneously form a driving electrode or a detection electrode, Al, Cr, Fe, Ni, Cu, Ag, Au, Pt, or alloys containing at least one of these metals are preferred.

[0090] Furthermore, examples of inorganic compounds include oxide ceramics such as aluminum oxide, silicon dioxide, titanium dioxide, zirconium oxide, yttrium oxide, and calcium phosphate; nitride ceramics such as silicon nitride, aluminum nitride, titanium nitride, and boron nitride; carbide ceramics such as graphite and tungsten carbide; and ferroelectric materials such as barium titanate, strontium titanate, PZT, PLZT, and PLLZT. Among these, insulating materials such as silicon dioxide (SiO2), titanium dioxide (TiO2), and aluminum oxide (Al2O3) are preferred.

[0091] Specifically, the preferred weighted films 51-56 are, for example, structures obtained by laminating an upper layer containing Au (gold) onto a base layer containing Cr (chromium). This results in excellent fit with the vibrator 4 formed using quartz, and allows for high-precision and efficient adjustment of the resonant frequency.

[0092] Furthermore, the average thickness of each weighted film 51 to 56 is not particularly limited, but for example, it is 10 nm or more and 10,000 nm or less.

[0093] In the vibration element 1 described above, when no angular velocity is applied to the vibration element 1, and an electric field is generated between the drive signal electrode (on which a drive signal has been input) and the drive ground electrode, each drive vibration arm 44-47... Figure 3 The bending vibration, i.e., the driven vibration, occurs in the direction indicated by arrow α. At this time, due to the driving vibration arms 44, 45 and 46, 47... Figure 3The base 41 and the detection vibration arms 48 and 49 vibrate almost symmetrically, so the vibration is almost non-vibrating.

[0094] When this driven vibration is applied, an angular velocity ω about axis a along the Z-axis is applied to the vibrating element 1, exciting the detection vibration (i.e., the vibration of the detection mode). Specifically, this applies to the driving vibration arms 44-47 and the connecting arms 42 and 43. Figure 3 The Coriolis force in the direction indicated by the middle arrow γ excites a new vibration. Simultaneously, the vibrations detected by the vibrating arms 48 and 49 are excited... Figure 3 The vibration is detected in the direction indicated by the middle arrow β to counteract the vibration of the connecting arms 42 and 43. Furthermore, the charge generated in the vibrating arms 48 and 49 by the vibration is obtained from the detection signal electrode as a detection signal, and the angular velocity is calculated based on the detection signal.

[0095] 3. Manufacturing methods for physical quantity sensors

[0096] Next, taking the manufacture of the physical quantity sensor 10 described above as an example, the manufacturing method of the physical quantity sensor including the manufacturing method of the vibration element will be described.

[0097] Figure 5 This is a flowchart illustrating an example of a method for manufacturing a vibrating element. For example... Figure 5 As shown, the manufacturing method of the physical quantity sensor 10 includes [1] a vibration element forming step (step S1), [2] an mounting step (step S2), [3] a frequency adjustment step (step S3), and [4] a sealing step (step S4). Here, the manufacturing method of the physical quantity sensor 10 includes a frequency adjustment method for the vibration element 1 and a manufacturing method for the vibration element 1. The frequency adjustment method for the vibration element 1 includes at least [3] of the above-described [1] to [4] steps. The manufacturing method for the vibration element 1 includes at least [1] and [3] of the above-described [1] to [4] steps. Hereinafter, each step will be described in turn.

[0098] [1] Vibration element forming process (step S1)

[0099] Figure 6 This is a top view of the vibrating element obtained through the vibrating element forming process. Furthermore, Figure 7 It is a bottom view of the vibrating element obtained through the vibrating element forming process.

[0100] First, formation Figure 6 The vibrating element 1a shown is used as the vibrating element before frequency adjustment. That is, in this process, as... Figure 6As shown, a vibrating element 1a is formed having a weighted film pattern 5a, which has weighted films 55, 56 and weighted films 51a, 52a, 53a, 54a before forming recesses 511, 521, 531, 541.

[0101] Specifically, for example, first, a quartz substrate is prepared as the raw material for the vibrator 4. A photoresist is coated on one side of the quartz substrate and exposed and developed to form a shape corresponding to the vibrator 4, thereby obtaining a photoresist mask (not shown). Next, with the photoresist mask formed, a Cr layer and an Au layer are sequentially formed on two sides of the quartz substrate, for example, by vapor deposition or sputtering. Then, a Ni layer is formed on the Au layer, for example, by plating. Afterward, the photoresist mask is removed, for example, by etching, to obtain the mask.

[0102] Next, the quartz substrate is dry-etched from one side through a mask, for example, by reactive ion etching (RIE) using C4F8 as the etching gas. This forms the vibrator 4. Furthermore, at this stage, the vibrator 4 is connected to other parts of the quartz substrate (i.e., in the "wafer state"). In this wafer state, the vibrator 4 is connected to other parts of the quartz substrate, for example, via a folded portion, where at least one of the width and thickness of the folded portion is small, making it relatively fragile. Moreover, in the wafer state, multiple vibrating elements 1 can be formed simultaneously on the quartz substrate.

[0103] Next, a metal film is uniformly formed on the surface of the vibrator 4 using a film-forming apparatus such as a sputtering device. Then, a photoresist mask is obtained by coating a photoresist and performing exposure and development. Finally, the portion of the metal film exposed from the photoresist mask is removed using an etching solution. Thus, an electrode film pattern is formed.

[0104] Next, a weighted film pattern 5a is formed on the electrode film pattern, for example by mask evaporation.

[0105] Vibrating element 1a is formed as described above.

[0106] Furthermore, after the vibrating element 1a is formed, a detuning frequency adjustment process can be performed as needed to adjust the detuning frequency, which is the difference between the resonant frequencies of the detection vibrating arms 48 and 49 and the resonant frequencies of the driving vibrating arms 44 to 47. In the detuning frequency adjustment process, for example, the resonant frequencies of the detection vibrating arms 48 and 49 and the driving vibrating arms 44 to 47 are measured, and at least a portion of the weighting films 55 and 56 is removed based on the measurement results. Depending on the situation, sometimes a portion of the weighting films 51, 52, 53, and 54 of the driving vibrating arms are also removed. Thus, the resonant frequencies of the detection vibrating arms 48 and 49 or the resonant frequencies of the driving vibrating arms 44 to 47 can be adjusted, thereby adjusting the detuning frequency.

[0107] Furthermore, this process can also be a process for preparing a vibrating element 1a formed by other methods.

[0108] [2] Installation procedure (step S2)

[0109] Next, although not shown, the vibrating element 1a in its wafer state is cut away from the quartz substrate. This is, for example, the process of breaking off the folded portion. Then, the vibrating element 1a is mounted on the base 111 of the aforementioned package 11 (see reference). Figure 1 Additionally, in this process, the cover 112 is not joined to the base 111. Furthermore, in this process, the circuit element 14 is fixed to the lower stepped surface of the recess in the base 111 by the adhesive 16, and the wiring pattern 13 is connected to a plurality of connection terminals provided on the upper stepped surface of the recess in the base 111 by a conductive adhesive 17 (see reference). Figure 1 ).

[0110] [3] Frequency adjustment process (step S3)

[0111] Figure 8 This is a top view of the vibrating element in the frequency adjustment process.

[0112] Next, a portion of the weighted membranes 51a to 54a is removed to adjust the vibration leakage, so that the resonant frequencies of the drive vibration arms 44 to 47 are equal. Here, "vibration leakage" refers to the magnitude of the signal (i.e., deviation or zero-point signal) output from the detection vibration arms 48 and 49 when the drive vibration arms 44 to 47 are driven to vibrate without rotation.

[0113] In this process, firstly, the resonant frequencies of the drive vibrating arms 44-47 are measured. Then, a predetermined amount is removed from at least one of the weighting films 51a-54a, and the resulting change in drive frequency is measured to determine the change in drive frequency relative to the processing amount. Additionally, the resonant frequencies of the drive vibrating arms 44-47 are measured for each of the plurality of vibrating bodies 4, and the change in drive frequency is determined.

[0114] Next, based on the measurement results of the resonant frequency of the driving vibrating arms 44-47 and the change in driving frequency relative to the machining amount, such as Figure 8 As shown, a portion of the weighting films 51a-54a is irradiated with energy line E to remove a portion of the weighting films 51a-54a, so that the resonant frequencies of the driving vibrating arms 44-47 are equal. Thus, as... Figure 3 As shown, recesses 511, 521, 531, and 541 are formed. As a result, the mass of the weighted membranes 51a to 54a is reduced, allowing adjustment of the resonant frequency of the driving vibrating arms 44 to 47.

[0115] For the energy line E, a laser with a pulse width of 1 picosecond or less (e.g., excimer laser, ion beam, etc.) is preferably used. In particular, plasma beams such as FIB (Focused Ion Beam) and IBF (Ion Beam Figuring) are preferred. Furthermore, using FIB enables finer processing with higher precision. Using IBF enables rapid fine processing, thus improving productivity.

[0116] like Figure 8 As shown, the regions S51, S52, S53, and S54 that irradiate the energy line E are, for example, the regions located on the end side of the upper surface of the weighted portions 441, 451, 461, and 471. Furthermore, it is preferable that regions S51 and S53 are linearly symmetrical about the line segment A passing through the center of the base body 410 as an axis of symmetry. Similarly, it is preferable that regions S52 and S54 are linearly symmetrical about the line segment A passing through the center of the base body 410 as an axis of symmetry. Furthermore, it is preferable that regions S51 to S54 have the same shape and the same area when viewed in planar view. The area of ​​regions S51 to S54 when viewed in planar view is, for example, 1 μm. 2 ~20000μm 2 about.

[0117] Furthermore, preferably, the irradiation time, irradiation amount, or output of the energy line E is set for each region S51 to S54 based on the measurement results of the resonant frequency of the driving vibrating arms 44 to 47 and the change in the driving frequency relative to the processing amount. This allows for high-precision matching of the resonant frequencies of the driving vibrating arms 44 to 47. In this embodiment, as an example, the irradiation time, irradiation amount, or output of the energy line E for regions S51 and S52 is set to be greater than that for regions S53 and S54.

[0118] As described above Figure 1The vibration element 1 is shown. In this embodiment, as an example, the depth d1 of the recess 511 of the driving vibration arm 44 is made deeper than the depth d3 of the recess 531 of the driving vibration arm 46 (see reference). Figure 4 Furthermore, although not shown in the figure, as an example, the depth d2 of the recess 521 of the driving vibrating arm 45 is made deeper than the depth d4 of the recess 541 of the driving vibrating arm 47. Additionally, the relationship between depths d1 and d3 and the relationship between depths d2 and d4 can be reversed. As a result, the depths of recesses 511, 521, 531, and 541 can also be the same. Furthermore, as long as the recesses 511, 521, 531, and 541 are provided as needed, it is also possible to have no recesses at all.

[0119] Alternatively, structures to suppress the encirclement of energy lines E can be provided on the drive vibration arms 44, 45, 46, and 47 as needed. Examples of such structures include those protruding from a surface parallel to the Y-axis (the side surface of the weighting parts 441, 451, 461, and 471) and a surface parallel to the X-axis (the outermost surface). By providing such structures, the energy lines E that are intended to encircle can be blocked, suppressing unexpected irradiation by the energy lines E.

[0120] Furthermore, it is also useful to sufficiently reduce the beam size of the energy line E as needed. That is, the energy line E can be focused to a sufficiently small size, or the opening of the mask restricting the irradiation area can be sufficiently reduced. Thus, unexpected irradiation by the energy line E can be suppressed.

[0121] In addition, the surfaces of the recesses 511, 521, 531, and 541 of the vibrating element 1 become exposed dangling bonds by the irradiation of the energy line E, that is, they become chemically activated.

[0122] [4] Sealing process (step S4)

[0123] Next, the cover 112 is joined to the base 111 via the engaging member 113, sealing the recess of the base 111. This encloses the vibrating element 1 within the package 11. The sealing process is performed after the cover 112 is joined, creating a predetermined environment within the package 11, such as a vacuum state.

[0124] The connection between the cover 112 and the base 111 is performed by providing a connecting member 113, such as a seam ring, on the base 111, and after the cover 112 is placed on the connecting member 113, the connecting member 113 is seam welded to the base 111, for example, using a resistance welding machine.

[0125] Figure 9 This is a plan view of the vibrating element in the sealing process.

[0126] In this process, since it is seam welding, gas generated by adhesive 16 or conductive adhesive 17 is produced inside the package 11. For example, if silicone adhesive is used for adhesive 16 or conductive adhesive 17, the interior of the package 11 becomes filled with silicone-containing gas. Here, as described above, the surfaces of recesses 511, 521, 531, and 541 are in a state of exposed dangling bonds, i.e., chemically active. Therefore, the dangling bonds on the surfaces of recesses 511, 521, 531, and 541 are in a state where they can easily chemically combine with various organic substances or moisture contained in the gas generated by adhesive 16 or conductive adhesive 17 (see reference). Figure 9 The reason is that during seam welding, for example, within a short period of time (about a few seconds), the dangling bonds on the surfaces of recesses 511, 521, 531, and 541 bond with the material M.

[0127] Next, the gas generated inside the package 11 during seam welding is discharged through the through-hole 115 within the vacuum chamber (not shown), and then the through-hole 115 is sealed by the sealant 116 (see reference). Figure 1 ).

[0128] It can form a physical quantity sensor 10 as described above.

[0129] Here, because the bonding between the aforementioned material M and the recesses 511, 521, 531, and 541 accumulates over time, the resonant frequency of the driving vibrating arms 44-47 changes over time. In other words, regardless of how the recesses 511, 521, 531, and 541 are formed to adjust the resonant frequency of the driving vibrating arms 44-47, these recesses will cause the bonding of material M. As a result, there is a concern that the vibrational balance of the driving vibrating arms 44-47 may deviate over time.

[0130] To eliminate this concern, as described later, the areas of the recesses 511, 521, 531, and 541 were adjusted relative to each other. That is, it was considered that even assuming substance M is adsorbed in the recesses 511, 521, 531, and 541, the amount of adsorption would not easily deviate from each other. Therefore, deviations in the vibration balance of the driving vibrating arms 44-47 can be suppressed to a certain extent.

[0131] However, although the weighted films 51a, 52a, 53a, and 54a are generally present at the locations irradiated by the energy line E, sometimes the lower surfaces of the weighted portions 441, 451, 461, and 471 may also be unexpectedly irradiated by the energy line E due to encirclement or other reasons. This unexpected irradiation results in the formation of substance M not only on the weighted films 51a, 52a, 53a, and 54a, but also on the lower surfaces of the weighted portions 441, 451, 461, and 471. In this case, because it is difficult to control the irradiation area of ​​the energy line E on the lower surfaces of the weighted portions 441, 451, 461, and 471, it is also difficult to control the amount of substance M formed, and the deviation in the vibration balance of the driving vibrating arms 44-47 may increase over time.

[0132] Therefore, in this embodiment, the activation amount activated by the energy line E is different between the upper surfaces of the weighting films 51a, 52a, 53a, and 54a of the driving vibration arms 44, 45, 46, and 47 of the vibration element 1a and the lower surfaces of the weighting parts 441, 451, 461, and 471.

[0133] Specifically, in this embodiment, the upper surfaces of the weight-bearing membranes 51a, 52a, 53a, and 54a of the driving vibration arms 44, 45, 46, and 47 of the vibration element 1a are designated as "first main surfaces 4411, 4511, 4611, and 4711", and the lower surfaces are designated as "second main surfaces 4412, 4512, 4612, and 4712".

[0134] That is, in this embodiment, such as Figure 6 As shown, weight-applying films 51a, 52a, 53a, and 54a are provided on a portion of the upper surface of the weight-applying portions 441, 451, 461, and 471, respectively, and each of these upper surfaces is a "first main surface 4411, 4511, 4611, and 4711". On the other hand, in this embodiment, as... Figure 7 As shown, the constituent material of the vibrator 4, such as quartz, is exposed on the entire lower surface of the weighting portions 441, 451, 461, and 471. That is, no weighting membrane is provided on the lower surface of the weighting portions 441, 451, 461, and 471. Therefore, in this embodiment, Figure 7 The entire lower surface of the weighted parts 441, 451, 461, and 471 shown is “the second main surface 4412, 4512, 4612, and 4712”.

[0135] Furthermore, the constituent materials of the first principal surfaces 4411, 4511, 4611, 4711 and the second principal surfaces 4412, 4512, 4612, 4712 are different from each other. Then, when these surfaces are irradiated with energy line E, the activation amount of the second principal surfaces 4412, 4512, 4612, 4712 is less than that of the first principal surfaces 4411, 4511, 4611, 4711.

[0136] The activation level, determined by energy line E, is a property that affects the amount of substance M bound. That is, the greater the activation level, the greater the amount of substance M bound. Therefore, the greater the activation level, the easier it is for the vibration equilibrium of the vibrating arms 44-47 to deviate significantly over time. Furthermore, the amount of irradiation by energy line E also affects the amount of substance M bound; the greater the irradiation, the greater the amount of substance M bound.

[0137] Based on this, in this embodiment, the activation amount of the second principal surfaces 4412, 4512, 4612, and 4712 of the lower surfaces of the weighting portions 441, 451, 461, and 471 activated by the energy line E can be smaller than the activation amount of the first principal surfaces 4411, 4511, 4611, and 4711 of the upper surfaces of the weighting films 51a, 52a, 53a, and 54a activated by the energy line E. Therefore, even if the energy line E accidentally irradiates the lower surfaces of the weighting portions 441, 451, 461, and 471, it is less likely to cause the material M to bond with the lower surfaces. In other words, even though the irradiation doses of the energy lines E irradiating the second principal surfaces 4412, 4512, 4612, and 4712 are different, the deviation in the amount of substance M bound per unit irradiation dose in the second principal surfaces 4412, 4512, 4612, and 4712 is suppressed to a small extent because the amount of substance M bound per unit irradiation dose in these surfaces is originally small. Furthermore, the deviation caused by the increase in the amount bound over time is also suppressed to a small extent. Therefore, it is easy to suppress the increase in the vibration balance deviation of the driving vibrating arms 44-47 over time, and the generation of vibration leakage can be suppressed.

[0138] In summary, in the frequency adjustment method of the vibration element of this embodiment, the vibration element 1a has: a base 41; and driving vibration arms 44 to 47, which extend from the base 41 and have first main surfaces 4411, 4511, 4611, 4711 and second main surfaces 4412, 4512, 4612, 4712 that are opposite to each other. The frequency adjustment method of the vibration element has a frequency adjustment step, in which a portion of the upper surface of each of the first main surfaces 4411, 4511, 4611, 4711, i.e., the weighted films 51a, 52a, 53a, 54a, is removed by irradiating the vibration element 1a with an energy line E, thereby forming recesses 511, 521, 531, 541, thereby adjusting the resonant frequency of the vibration element 1a. Furthermore, the activation amount of the second principal surfaces 4412, 4512, 4612, and 4712 of the vibrating element 1a by the energy line E is smaller than the activation amount of the first principal surfaces 4411, 4511, 4611, and 4711 by the energy line E.

[0139] According to this method, since the amount of substance M bonded is suppressed to be significantly different on the second principal surfaces 4412, 4512, 4612, and 4712, even if the energy line E is accidentally irradiated on the second principal surfaces 4412, 4512, 4612, and 4712, it is easy to suppress the deviation of the vibration balance of the driving vibrating arms 44 to 47 over time. As a result, vibration leakage in the vibrating element 1 can be suppressed.

[0140] Furthermore, the vibrating element 1a has: a base 41; and driving vibrating arms 44 to 47, which extend from the base 41 and have first main surfaces 4411, 4511, 4611, 4711 and second main surfaces 4412, 4512, 4612, 4712 that are in opposite directions. The activation amount of the second main surfaces 4412, 4512, 4612, 4712 activated by the energy line E is smaller than the activation amount of the first main surfaces 4411, 4511, 4611, 4711 activated by the energy line E.

[0141] According to such a vibrating element 1a, since the amount of substance M bonded is suppressed to be significantly different on the second principal surfaces 4412, 4512, 4612, and 4712, even if the energy line E is accidentally irradiated on the second principal surfaces 4412, 4512, 4612, and 4712, it is easy to suppress the deviation of the vibration balance of the driving vibrating arms 44 to 47 over time. Therefore, a vibrating element 1 that suppresses vibration leakage can be obtained.

[0142] Furthermore, as mentioned above, Figure 3The drive vibration arms 44, 45, 46, and 47 shown have: arm portions 440, 450, 460, and 470 located on the side of the base 41; weighting portions 441, 451, 461, and 471 located on the end side of the arm portions 440, 450, 460, and 470, i.e., on the side opposite to the base 41; and weighting membranes 51, 52, 53, and 54, which are examples of frequency adjustment membranes.

[0143] With such driving vibrating arms 44-47, the area of ​​the first main surfaces 4411, 4511, 4611, and 4711, which are provided on the wider weighting sections 441, 451, 461, and 471, can be sufficiently increased. Therefore, the area and mass of the weighting membranes 51, 52, 53, and 54 can also be sufficiently increased, ensuring the adjustment width, adjustment efficiency, and accuracy of the resonant frequency.

[0144] Furthermore, in this embodiment, it is preferable that the first main surfaces 4411, 4511, 4611, and 4711, i.e., the weighting films 51, 52, 53, and 54, contain metallic material. In other words, in this embodiment, it is preferable that the first main surfaces 4411, 4511, 4611, and 4711 are surfaces containing metallic material. Therefore, the constituent materials of the first main surfaces 4411, 4511, 4611, and 4711 have a higher specific gravity, enabling efficient handling of mass changes when irradiated by the energy line E. Furthermore, metallic materials have better processability based on the energy line E. As a result, the resonant frequency of the vibrating element 1a can be adjusted efficiently.

[0145] On the other hand, in this embodiment, it is preferable that the second main surfaces 4412, 4512, 4612, and 4712 contain an oxide material. That is, in this embodiment, it is preferable that the second main surfaces 4412, 4512, 4612, and 4712 are surfaces containing an oxide material. Examples of oxide materials include alumina, silicon oxide (such as quartz), titanium dioxide, zirconium oxide, and yttrium oxide, and one or more of these are used. By using such an oxide material, the activation amount of the second main surfaces 4412, 4512, 4612, and 4712 activated by the energy line E can be suppressed to a particularly small level. Therefore, it is possible to further suppress the significant differences in the amount of substance M bonded to each of the second main surfaces 4412, 4512, 4612, and 4712.

[0146] Furthermore, in this embodiment, since no weighting film is provided on the lower surfaces of the weighting portions 441, 451, 461, and 471, the second main surfaces 4412, 4512, 4612, and 4712 are, for example, surfaces containing a material that constitutes the vibrator 4, such as quartz. Quartz generally has a higher cleanliness than other materials; that is, it is a material with a smaller amount of initially attached substance M, and it also has higher uniformity of cleanliness and smaller deviations in cleanliness based on location. Therefore, for example, situations where the cleanliness of each driving vibrating arm 44, 45, 46, and 47 is greatly different are avoided, and the deterioration of mass balance associated with differences in cleanliness can be avoided. Therefore, the resonant frequency can be adjusted with higher precision.

[0147] Furthermore, "lower activation amount" refers to, firstly, a lower amount of organic matter adhering per unit area in the irradiated region of energy line E. Therefore, it means that the amount of organic matter adhering is lower under the assumption that it occurs under specified conditions. Moreover, it is sufficient that the activation amount of the second main surfaces 4412, 4512, 4612, and 4712 activated by energy line E is lower than the activation amount of the first main surfaces 4411, 4511, 4611, and 4711 activated by energy line E, but preferably 95% or less, more preferably 90% or less, of the activation amount of the first main surfaces.

[0148] Furthermore, the activation level can be evaluated by measuring the amount of organic matter attached, as shown below.

[0149] First, prepare 10 vibrating plates with an area of ​​0.2 mm × 0.2 mm or larger to measure the surface condition of the target area. Measure the carbon content of the target area's surface before exposure to an organic atmosphere using XPS (X-ray Photoelectron Spectroscopy). Then, calculate the average carbon content of the 10 samples. For example, a ULVAC-PHI Quantera II XPS device can be used.

[0150] Next, these vibrating discs and 2 ml of grease placed in a glass dish were sealed in a glass container under atmospheric pressure and exposed to an organic atmosphere at 25°C for 168 hours. Similar to the pre-exposure measurements, the carbon content of the surface area of ​​the exposed samples was measured using XPS, and the average carbon content of 10 samples was calculated. For example, AFE-CA grease manufactured by THK could be used as the grease. The difference in average carbon content of the surface before and after the organic atmosphere exposure was used as an indicator of the activation level.

[0151] Furthermore, the ease of attachment of organic matter is affected by the interatomic bonding forces in the irradiated region of energy line E. Therefore, "lower activation amount" also refers to the fact that the material is composed of a material with relatively strong interatomic bonding forces in the attachment region. Specifically, since the interatomic bonding forces decrease in the order of covalent bonds, ionic bonds, and metallic bonds, for example, if the first principal surfaces 4411, 4511, 4611, and 4711 contain metallic materials and the second principal surfaces 4412, 4512, 4612, and 4712 contain oxide materials, the atoms in the metallic materials are metallic bonds, while the atoms in the oxide materials are covalent bonds. Therefore, it can be said that the activation amount of the second principal surfaces 4412, 4512, 4612, and 4712 activated by energy line E is smaller than that of the first principal surfaces 4411, 4511, 4611, and 4711 activated by energy line E.

[0152] Furthermore, in this case, it is preferable that the molecular weight or atomic mass of the material (e.g., oxide material) contained in the second main surfaces 4412, 4512, 4612, and 4712 is smaller than the atomic mass or molecular weight of the material (e.g., metallic material) contained in the first main surfaces 4411, 4511, 4611, and 4711. This results in a greater difference in activation levels and a more significant effect.

[0153] In addition, the various metal materials mentioned above are examples of such metal materials.

[0154] Furthermore, compared to the first principal surfaces 4411, 4511, 4611, and 4711 containing materials with relatively high activation levels (such as metallic materials), the second principal surfaces 4412, 4512, 4612, and 4712 containing materials with relatively low activation levels (such as oxide materials) tend to have a lower processing rate for the energy line E, i.e., a smaller processing amount per unit time. Therefore, it can be said that the second principal surfaces 4412, 4512, 4612, and 4712 not only have relatively low amounts of organic matter adhering to them, but are also not easy to process themselves. Thus, such second principal surfaces 4412, 4512, 4612, and 4712 can also suppress the decrease in the resonant frequency adjustment accuracy associated with unexpected processing and resulting mass reduction.

[0155] On the other hand, the materials contained in the second main surfaces 4412, 4512, 4612, and 4712, in addition to oxide materials, include nitride materials such as silicon nitride, aluminum nitride, titanium nitride, and boron nitride; carbide materials such as silicon carbide, graphite, and tungsten carbide; ferroelectric materials such as barium titanate, strontium titanate, PZT, PLZT, and PLLZT; and various resin materials. One or more of these materials can be used in combination.

[0156] Furthermore, the aforementioned relationship of activation amounts must be true for at least a portion of the upper surfaces of the weighting portions 441, 451, 461, and 471 and the lower surfaces of the weighting portions 441, 451, 461, and 471.

[0157] Specifically, in Figure 3 In this process, a portion of the upper surface of each of the weight-applying parts 441, 451, 461, and 471 is provided with weight-applying membranes 51, 52, 53, and 54. That is, a portion of the upper surface of each of the weight-applying parts 441, 451, 461, and 471 is the first main surface 4411, 4511, 4611, and 4711.

[0158] In this way, even if the above-mentioned activation amount is in the order of the upper and lower surfaces of the weighted parts 441, 451, 461, and 471, the above-mentioned effect can still be obtained.

[0159] In addition, it is preferable that the first main surfaces 4411, 4511, 4611, and 4711 occupy more than 50% of the area of ​​each upper surface of the weight-bearing parts 441, 451, 461, and 471, and more preferably more than 70%.

[0160] Similarly, it is preferable that the second main surfaces 4412, 4512, 4612, and 4712 occupy more than 50% of the area of ​​each lower surface of the weight-bearing parts 441, 451, 461, and 471, and more preferably more than 70%.

[0161] Furthermore, the vibrator 4 in this embodiment is formed in a so-called double-T shape. Therefore, the vibrating element 1a has a pair of driving vibrating arms 44, 46 and a pair of driving vibrating arms 45, 47 extending from the base 41 in the same direction as each other. Since the shape of such a vibrating element 1a has high symmetry, the resonant frequency can be easily adjusted based on the energy line E, resulting in a vibrating element 1 with less vibration leakage.

[0162] Furthermore, the recesses 511, 521, 531, and 541 can be of any shape, but in this embodiment, their shapes are set such that they have the same area when viewed in a plane from the thickness direction of the base 41. That is, in this embodiment, when viewed in a plane from the thickness direction of the base 41, the area of ​​the region irradiated with energy line E by one driving vibrating arm 44 (i.e., recess 511) is set to be the same as the area of ​​the region irradiated with energy line E by another driving vibrating arm 46 (i.e., recess 531). Similarly, the area of ​​the region irradiated with energy line E by one driving vibrating arm 45 (i.e., recess 521) is set to be the same as the area of ​​the region irradiated with energy line E by another driving vibrating arm 47 (i.e., recess 541). Thus, the amount of substance M bonded to the recesses 511, 521, 531, and 541 can be approximately equal to each other. As a result, after adjusting the resonant frequency of the drive vibration arms 44-47 by forming the recesses 511, 521, 531, and 541, it is possible to suppress the deviation of the vibration balance of the drive vibration arms 44-47 over time.

[0163] Furthermore, the area of ​​the recesses 511, 521, 531, and 541 when viewed from a plane is not particularly limited, but for example, it is 1 μm. 2 ~20000μm 2 about.

[0164] Furthermore, multiple recesses may be formed in the drive vibration arms 44-47 respectively. In this case, it is also preferable that the sum of the areas of the recesses in each of the drive vibration arms 44-47 is the same.

[0165] Furthermore, in this specification, "identical" and "equal" mean practically identical or equal, referring to errors including mechanical design and setup. Therefore, "identical" and "equal" refer to cases where the difference between objects is within ±5%.

[0166] Furthermore, the areas of the recesses 511, 521, 531, and 541 when viewed in a plane do not necessarily need to be the same; they can also be different from each other.

[0167] Furthermore, recesses 511 and 531 can be formed at any position on the weighting films 51 and 53, but in this embodiment, their positions in the X-axis direction are set at positions that are linearly symmetrical about a line segment A passing through the center of the base 41 and parallel to the Y-axis. Similarly, recesses 521 and 541 are set at positions that are linearly symmetrical about a line segment A. In this embodiment, recesses 511, 521, 531, and 541 are located at the end sides of the weighting portions 441, 451, 461, and 471 in the Y-axis direction. This allows for efficient and high-precision adjustment of the resonant frequencies of the drive vibrating arms 44-47, which require minute adjustments.

[0168] Furthermore, regarding the depths of recesses 511, 521, 531, and 541, in this embodiment, at least one of the recesses 511, 521, 531, and 541 has a different depth than the other recesses. Therefore, while keeping the area of ​​the recesses 511, 521, 531, and 541 almost constant when viewed in a plane from the thickness direction of the base 41, their volumes can be made different from each other. In other words, while keeping the amount of substance M bonded to the recesses 511, 521, 531, and 541 almost constant, the masses of the weighting films 51, 52, 53, and 54 can be made different from each other, allowing adjustment of the resonant frequency of the driving vibrating arms 44-47. Therefore, after the resonant frequency of the driving vibration arms 44-47 is adjusted by forming the recesses 511, 521, 531, and 541, even if the recesses 511, 521, 531, and 541 are combined with the material M, it is not easy to cause an imbalance in the amount of combination. Therefore, it is possible to suppress the deviation of the vibration balance of the driving vibration arms 44-47 over time.

[0169] In addition, the depths d1 to d4 of the recesses 511, 521, 531, and 541 are approximately 1 nm to 2000 nm, respectively.

[0170] Furthermore, by changing the depth without altering the area of ​​the recesses 511, 521, 531, and 541 during planar observation, the amount of movement of the energy line E during scanning, i.e., the scan amount, can be minimized. This allows for easy and efficient frequency adjustment.

[0171] Furthermore, as a result of the resonant frequency adjustment, the depths of the recesses 511, 521, 531, and 541 can also be the same.

[0172] Furthermore, as described above, it is preferable that the pair of drive vibration arms 44 and 46 are parallel to each other when viewed in a plane. Similarly, it is preferable that the pair of drive vibration arms 45 and 47 are parallel to each other when viewed in a plane. As a result, the resonant frequencies of the drive vibration arms 44 to 47, which require fine adjustments, can be adjusted efficiently and with high precision.

[0173] Furthermore, as described above, the pair of drive vibration arms 44 and 46 are parallel to each other and extend to the same side relative to the base 41 when viewed in a planar view. Similarly, the pair of drive vibration arms 45 and 47 are parallel to each other and extend to the same side relative to the base 41 when viewed in a planar view.

[0174] According to such a vibration element 1 or vibration element 1a, deformation of the base 41, which is accompanied by bending vibrations that alternately approach and move away from each other in the XY plane, and bending vibrations that alternately approach and move away from each other from each other in the same direction, can be suppressed, thereby further suppressing vibration leakage from the base 41 to the outside. Furthermore, by using the adjustment method of this embodiment on such a vibration element 1 or vibration element 1a, vibration leakage caused by the deviation of the vibration balance of the driving vibration arms 44-47 over time is reduced. Therefore, a vibration element 1 with high precision and high stability can be achieved.

[0175] Additionally, in this specification, "parallel" refers to the allowable error during manufacturing.

[0176] As explained above, the manufacturing method of the vibration element 1 includes a frequency adjustment method for the vibration element 1a. Therefore, it is possible to obtain a vibration element 1 that reduces vibration leakage caused by the deviation of the vibration balance of the drive vibration arms 44-47 over time.

[0177] Furthermore, the physical quantity sensor 10 has a vibration element 1 and a package 11 housing the vibration element 1. As a result, a physical quantity sensor 10 with high precision and high stability can be realized.

[0178] 4. Inertial Measurement Unit

[0179] Figure 10 This is an exploded perspective view showing an embodiment of the inertial measurement device of the present invention. Figure 11 yes Figure 10 A three-dimensional view of the substrate of the inertial measurement device shown.

[0180] Figure 10 The inertial measurement unit 2000 (IMU) shown is a so-called 6-axis motion sensor, which is used, for example, to install on moving bodies (i.e., the objects being measured) such as cars and robots, to detect the posture and behavior (i.e., the amount of inertial motion) of the moving body.

[0181] The inertial measurement device 2000 has a housing 2100, a coupling member 2200, and a sensor module 2300, which is fitted inside the housing 2100 with the coupling member 2200 in between.

[0182] The outer casing 2100 is box-shaped, and threaded holes 2110 are provided at two opposite corners of the outer casing 2100. The threaded holes 2110 are used to thread the measuring object.

[0183] The sensor module 2300 has an inner shell 2310 and a substrate 2320. The inner shell 2310 is housed inside the outer shell 2100 while supporting the substrate 2320. Here, the inner shell 2310 is joined to the outer shell 2100 by an adhesive or the like via a joining member 2200 (e.g., a rubber gasket). The inner shell 2310 has a recess 2311, which functions as a storage space for components mounted on the substrate 2320; and an opening 2312, which exposes a connector 2330 provided on the substrate 2320 to the outside. The substrate 2320 is, for example, a multilayer wiring substrate, and is joined to the inner shell 2310 by an adhesive or the like.

[0184] like Figure 11 As shown, a connector 2330, angular velocity sensors 2340X, 2340Y, and 2340Z, an acceleration sensor 2350, and a control IC 2360 are mounted on the substrate 2320.

[0185] Connector 2330 is used for electrical connection with an external device (not shown) to transmit and receive electrical signals such as power and measurement data between the external device and the inertial measurement unit 2000.

[0186] Angular velocity sensor 2340X detects the angular velocity about the X-axis, angular velocity sensor 2340Y detects the angular velocity about the Y-axis, and angular velocity sensor 2340Z detects the angular velocity about the Z-axis. Here, angular velocity sensors 2340X, 2340Y, and 2340Z are the physical quantity sensors 10 mentioned above. Furthermore, accelerometer 2350 is, for example, an accelerometer formed using MEMS technology, detecting acceleration along each of the X, Y, and Z axes.

[0187] The control IC 2360 is a Micro Controller Unit (MCU) that integrates a storage unit including non-volatile memory, an A / D converter, etc., and controls various parts of the inertial measurement device 2000. The storage unit contains programs that define the order and content for detecting acceleration and angular velocity, programs for digitizing the detection data and importing it into grouped data, and supplementary data.

[0188] As described above, the inertial measurement device 2000 includes: physical quantity sensors 10 containing vibration elements 1, such as angular velocity sensors 2340X, 2340Y, and 2340Z; and a control IC 2360, which is a circuit electrically connected to the physical quantity sensors 10. With such an inertial measurement device 2000, the excellent sensor characteristics of the physical quantity sensors 10 can be utilized to improve the characteristics of the inertial measurement device 2000, such as measurement accuracy.

[0189] 5. Electronic equipment

[0190] Figure 12 This is a perspective view showing a mobile personal computer as an embodiment of the electronic device of the present invention.

[0191] In this figure, the personal computer 1100 consists of a main body 1104 with a keyboard 1102 and a display unit 1106 with a display unit 1108. The display unit 1106 is rotatably supported on the main body 1104 via a hinge structure. This personal computer 1100 incorporates an inertial measurement device 2000 that includes the aforementioned vibration element 1.

[0192] Figure 13 This is a top view showing a mobile phone as an embodiment of the electronic device of the present invention.

[0193] In this figure, the mobile phone 1200 has an antenna (not shown), multiple operation buttons 1202, a receiver 1204, and a call port 1206. A display unit 1208 is arranged between the operation buttons 1202 and the receiver 1204. This mobile phone 1200 incorporates an inertial measurement device 2000, including the aforementioned vibration element 1.

[0194] Figure 14 This is a perspective view showing a digital still camera as an embodiment of the electronic device of the present invention.

[0195] exist Figure 14 In this digital still camera 1300, a display unit 1310 is provided on the back of the housing 1302, configured to display the image signal from the CCD. The display unit 1310 functions as a viewfinder that displays the subject as an electronic image. Furthermore, a light-receiving unit 1304, including an imaging optical system such as an optical lens or a CCD, is provided on the front side of the housing 1302 (i.e., the back side in the figure). When the photographer confirms the image of the subject displayed on the display unit 1310 and presses the shutter button 1306, the image signal from the CCD at that time point is transmitted to the memory 1308 and stored. This digital still camera 1300 incorporates an inertial measurement unit 2000, including the aforementioned vibration element 1, and the measurement results of this inertial measurement unit 2000 are used, for example, for image stabilization.

[0196] The electronic device described above has a vibration element 1. With such an electronic device, the superior characteristics of the vibration element 1 can be utilized to improve the characteristics (e.g., reliability) of the electronic device.

[0197] In addition, the electronic device of the present invention, besides Figure 12 Personal computers Figure 13 mobile phones, Figure 14Besides digital still cameras, applications include smartphones, tablets, watches including smartwatches, inkjet printers, wearable devices such as HMDs (head-mounted displays), laptops, televisions, cameras, video recorders, car navigation systems, pagers, electronic notebooks with communication functions, electronic dictionaries, calculators, video game devices, word processors, workstations, video phones, anti-theft television monitors, electronic binoculars, POS terminals, medical devices (such as electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasound diagnostic devices, and electronic endoscopes), fish detectors, various measuring devices, measuring instruments (such as measuring instruments for vehicles, airplanes, and ships), base stations for portable terminals, and flight simulators.

[0198] 6. Moving objects

[0199] Figure 15 This is a perspective view showing a car as an embodiment of the mobile body of the present invention.

[0200] exist Figure 15 The automobile 1500 shown has an inertial measurement unit 2000 built into it, which includes the aforementioned vibration element 1. For example, the inertial measurement unit 2000 can detect the posture of the vehicle body 1501. The detection signal from the inertial measurement unit 2000 is provided to the vehicle posture control unit 1502. The vehicle posture control unit 1502 can detect the posture of the vehicle body 1501 based on the signal, and control the stiffness of the suspension and the braking of each wheel 1503 accordingly.

[0201] Furthermore, this type of posture control can be used in bipedal walking robots or radio-controlled helicopters such as drones. As mentioned above, an inertial measurement unit 2000 is assembled to achieve posture control of various moving bodies.

[0202] As described above, the automobile 1500, as a moving body, has a vibration element 1. According to such an automobile 1500, the excellent characteristics of the vibration element 1 can be utilized to improve the characteristics (e.g., reliability) of the automobile 1500.

[0203] The frequency adjustment method, manufacturing method, vibration element, physical quantity sensor, inertial measurement device, electronic device, and moving body of the present invention have been described above with reference to the illustrated embodiments. However, the present invention is not limited thereto, and the structure of each part can be replaced with any structure having the same function. Furthermore, other arbitrary structures can be added to the present invention.

[0204] Furthermore, in the above embodiment, the vibrating element has a weight-applying portion, but it may also not have a weight-applying portion. That is, the width of the region on the end side of the driving vibrating arm may be the same as the width of the region on the base side (i.e., the arm portion as well). In this case, it is sufficient to consider the region of the driving vibrating arm 30% from the end (i.e., 30% of the total length of the driving vibrating arm) as the weight-applying portion, and the magnitude relationship of the activation amount described above must be established between the first main surface and the second main surface.

[0205] Furthermore, the vibrating element has two sets of driving vibrating arms that are parallel to each other when viewed in a plane and extend to the same side relative to the base, but the pair of driving vibrating arms can also be one set.

[0206] Furthermore, in the above embodiments, the vibrating element is formed in a so-called double-T shape, but it is not limited to this. For example, it can also be in various forms such as H-shape, double-leg tuning fork, triple-leg tuning fork, orthogonal shape, prism shape, etc.

[0207] Furthermore, as the constituent material of the aforementioned vibrator, for example, piezoelectric materials other than quartz, such as lithium tantalate, lithium niobate, or piezoelectric ceramics, can also be used.

[0208] The entire disclosure of Japanese Patent Application No. 2018-065214, filed on March 29, 2018, is hereby clearly incorporated by reference.

Claims

1. A vibrating element, characterized in that, The vibrating element includes: A vibrating body includes a base and a vibrating arm, the vibrating arm including a first main surface and a second main surface that are opposite to each other, and including an arm extending from the base and a weight-applying part extending from the arm. Electrode film pattern disposed on the surface of the vibrator; and The weight-applying film pattern is disposed on the first main surface side of the weight-applying part. The activation amount on the second main surface of the weighting part is smaller than the activation amount on the first main surface of the weighting part after a portion of the weighting film pattern has been removed.

2. The vibration element according to claim 1, characterized in that, The activation amount on the second main surface side is the activation amount generated when irradiated by the energy line. The activation amount on the first main surface side is the activation amount generated when irradiated by an energy line.

3. The vibration element according to claim 2, characterized in that, The electrode film pattern is disposed on the first main surface and the arm portion of the weight-applying part. The weighting film pattern is disposed on the electrode film pattern disposed on the first main surface.

4. The vibration element according to claim 3, characterized in that, The vibrator is made of any one of the following materials: silicon oxide, lithium tantalate, lithium niobate, aluminum oxide, titanium oxide, zirconium oxide, yttrium oxide, silicon nitride, aluminum nitride, titanium nitride, boron nitride, silicon carbide, graphite, tungsten carbide, barium titanate, strontium titanate, PZT, PLZT, and PLLZT.

5. The vibration element according to claim 4, characterized in that, The material of the vibrating body is exposed on the second main surface of the weight-bearing part.

6. The vibration element according to claim 5, characterized in that, The material of the weighted film pattern is any one of Ni, Au, Pt, Al, Ag, Cr, Cu, Mo, Nb, W, Fe, Ti, Co, Zn, Zr, and alloys containing them.

7. The vibration element according to claim 6, characterized in that, The vibrating body is made of quartz. The material of the weighted film pattern is Au.

8. The vibration element according to claim 7, characterized in that, The arm portion is composed of a pair of arms extending from the base in the same direction to each other. The weight-applying section is composed of a pair of weight-applying sections extending from the pair of arms respectively.

9. The vibration element according to claim 8, characterized in that, When viewed in a plane from the thickness direction of the base, The area of ​​the region of one of the weight-bearing parts irradiated by the energy line is the same as the area of ​​the region of the other weight-bearing part irradiated by the energy line.

10. A physical quantity sensor, characterized in that, This physical quantity sensor includes: The vibrating element as claimed in claim 9; and The package contains the vibrating element.

11. An inertial measurement device, characterized in that, The inertial measurement device includes: The physical quantity sensor according to claim 10; and The circuit is electrically connected to the physical quantity sensor.

12. An electronic device, characterized in that, The electronic device includes: The vibrating element as claimed in claim 9; and The circuit outputs a drive signal to the vibrating element.

13. A mobile body, characterized in that, The mobile body includes: The vibrating element as claimed in claim 9; and The main body is equipped with a physical quantity sensor including the vibration element.

14. A method for adjusting the frequency of a vibrating element, characterized in that, The frequency adjustment method for the vibration element includes the following steps: Prepare a quartz substrate; The quartz substrate is etched to form a vibrating body, wherein the vibrating body includes a base and a vibrating arm, the vibrating arm includes a first main surface and a second main surface that are opposite to each other, and includes an arm extending from the base and a weighting portion extending from the arm. An electrode film pattern is formed on the surface of the vibrator, and a weighting film pattern is formed on the first main surface side of the weighting part, thereby forming a vibrating element in a wafer state; The vibrating element in the wafer state is cut into single vibrating elements; The monolithic vibrating element is mounted in a package; and By irradiating the weighted film pattern with energy lines to remove a portion of the pattern, the resonant frequency of the vibrating element is adjusted. The activation amount of the second main surface side of the weighting part activated by the energy line is smaller than the activation amount of the first main surface side of the weighting part activated by the energy line.

15. The frequency adjustment method for a vibrating element according to claim 14, characterized in that, The electrode film pattern is formed on the first main surface and the arm portion of the weighting part. The weighting film pattern is formed on the electrode film pattern disposed on the first main surface.

16. The frequency adjustment method for a vibrating element according to claim 15, characterized in that, In the process of forming the vibrating element in the wafer state, On the second main surface of the weighted part, the quartz is exposed.

17. The frequency adjustment method for a vibrating element according to claim 16, characterized in that, The material of the weighted film pattern is any one of Ni, Au, Pt, Al, Ag, Cr, Cu, Mo, Nb, W, Fe, Ti, Co, Zn, Zr, and alloys containing them.

18. A method for manufacturing a vibrating element, characterized in that, The method for manufacturing the vibrating element includes the frequency adjustment method for the vibrating element as described in any one of claims 14 to 17.

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