Resonator device, collection substrate, and method for manufacturing resonator device

Abstract

The present application provides a resonant device capable of inhibiting the propagation of noise through a holding portion, a collection substrate, and a manufacturing method of the resonant device. The resonant device (1) comprises: a MEMS substrate (50) containing a resonator (10) having a vibration portion (110) and a holding portion (140) configured to hold the vibration portion (110); and an upper cover (30) configured to be opposite to the MEMS substrate (50) and sandwiching the resonator (10) in the middle, and containing a connection wire (CW1) electrically connected with the vibration portion (110), the resonator (10) further has a separation groove (145) formed to surround the vibration portion (110) when viewed from above.

Description

Technical Field

[0001] The present invention relates to a resonant device, an aggregate substrate, and a method for manufacturing the resonant device. Background Art

[0002] Conventionally, devices manufactured using, for example, MEMS (Micro Electro Mechanical Systems) technology have become widespread. These devices are manufactured by, for example, forming a plurality of devices on a collective substrate (wafer), then dividing the wafer into individual devices (chips).

[0003] For example, Patent Document 1 discloses a resonant device including a resonator. The resonator is electrically connected to a holding portion, a support arm, and a vibrating portion via a degenerate silicon (Si) substrate or a metal film. In Patent Document 1, a frequency adjustment process is performed using an ion trimming method or the like to adjust the resonant frequency of the vibrating portion while the substrate is still in its assembled state before being divided into individual resonant devices.

[0004] Patent Document 1: International Publication No. 2016 / 174789

[0005] However, in the aggregate substrate disclosed in Patent Document 1, multiple resonant devices are arranged adjacent to each other, with the retaining portions of adjacent resonators conductive. Consequently, noise generated during trimming and other processes can easily propagate through the retaining portions to the vibrating portions of adjacent resonant devices. As a result, when adjusting the resonant frequency of the vibrating portion, for example, the accuracy of the adjustment can be reduced due to the reduced measurement accuracy caused by the propagated noise. Summary of the Invention

[0006] The present invention has been made in view of the above circumstances, and one object of the present invention is to provide a resonant device, an aggregate substrate, and a method for manufacturing the resonant device that can suppress propagation of noise via a holding portion.

[0007] A resonant device according to one aspect of the present invention comprises: a first substrate including a resonator having a vibrating portion and a retaining portion, wherein the retaining portion is configured to retain the vibrating portion; and a second substrate arranged to oppose the first substrate and sandwich the resonator therebetween, and including a first connecting portion electrically connected to the vibrating portion, wherein the resonator further comprises a separation groove formed so as to surround the vibrating portion when viewed from above.

[0008] Another aspect of the present invention relates to an aggregate substrate for manufacturing a resonant device, comprising: a first substrate including a plurality of resonators, each resonator having a vibrating portion and a holding portion, wherein the holding portion is configured to hold the vibrating portion; and a second substrate, arranged to be opposite to the first substrate and sandwiching the plurality of resonators therebetween, and including a plurality of first connecting portions electrically connected to the respective vibrating portions of the plurality of resonators, wherein the plurality of resonators further each have a separation groove, wherein the separation groove is formed to surround the vibrating portion when viewed from above.

[0009] Another aspect of the present invention relates to a method for manufacturing a resonant device, comprising: a process of preparing a first substrate and a second substrate, the first substrate including a plurality of resonators, each resonator having a vibrating portion and a holding portion, the holding portion being configured to hold the vibrating portion, the second substrate being arranged opposite to the first substrate and sandwiching the plurality of resonators therebetween, and including a plurality of first connecting portions electrically connected to the vibrating portions of the respective plurality of resonators; a process of joining the first substrate and the second substrate; and a process of dividing the first substrate and the second substrate along a dividing line for dividing the plurality of resonant devices, the plurality of resonators each further having a separation groove, the separation groove being formed to surround the vibrating portion when viewed from above.

[0010] According to the present invention, propagation of noise via the holding portion can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a perspective view schematically showing the appearance of a resonance device in one embodiment.

[0012] Figure 2 It is briefly shown Figure 1 An exploded perspective view of the structure of the resonant device shown.

[0013] Figure 3 It is briefly shown Figure 2 A top view of the structure of the resonator shown.

[0014] Figure 4 It is briefly shown Figure 1 A cross-sectional view along the X-axis of the stacked structure of the resonant device shown.

[0015] Figure 5 It is conceptually shown Figure 1 A cross-sectional view along the Y-axis of the stacked structure of the resonant device shown.

[0016] Figure 6 It is briefly shown Figures 1 to 5 A top view of the resonator and its surrounding wiring is shown.

[0017] Figure 7 It is briefly shown Figure 6An enlarged cross-sectional view of the stacked structure of the connecting components shown.

[0018] Figure 8 This is an exploded perspective view schematically showing the appearance of an aggregate substrate in one embodiment.

[0019] Figure 9 It is magnified Figure 8 A partial enlarged view of area A is shown.

[0020] Figure 10 This is a flowchart showing a method for manufacturing a resonant device in one embodiment.

[0021] Figure 11 This is a plan view schematically showing a resonator and its surrounding wiring of a resonant device in a modified example of one embodiment.

[0022] Figure 12 It is briefly shown Figure 11 An enlarged cross-sectional view of the stacked structure of the connecting components shown. DETAILED DESCRIPTION

[0023] The following describes an embodiment of the present invention. In the following drawings, identical or similar components are represented by identical or similar reference numerals. The drawings are illustrative only, and the dimensions and shapes of the various components are schematic. The technical scope of the present invention should not be limited to the embodiments.

[0024] Resonance Device

[0025] First, refer to Figure 1 as well as Figure 2 , and describes a brief structure of a resonance device according to one embodiment. Figure 1 It is a perspective view schematically showing the appearance of the resonance device 1 according to one embodiment. Figure 2 It is briefly shown Figure 1 The structure of the resonance device 1 is shown in an exploded perspective view.

[0026] like Figure 1 as well as Figure 2 As shown, the resonator device 1 includes a resonator 10, and a lower cover 20 and an upper cover 30 that form a vibration space in which the resonator 10 vibrates. Specifically, the resonator device 1 is constructed by stacking the lower cover 20, the resonator 10, a bonding portion 60 (described later), and the upper cover 30 in this order. The MEMS substrate 50 (lower cover 20 and resonator 10) of this embodiment corresponds to an example of the "first substrate" of the present invention, and the upper cover 30 of this embodiment corresponds to an example of the "second substrate" of the present invention.

[0027] Hereinafter, the components of the resonant device 1 will be described. In the following description, the side of the resonant device 1 where the upper cover 30 is provided is referred to as the upper side (or front side), and the side where the lower cover 20 is provided is referred to as the lower side (or back side).

[0028] Resonator 10 is a MEMS oscillator manufactured using MEMS technology. Resonator 10 and upper cover 30 are bonded via a bonding portion 60. Furthermore, resonator 10 and lower cover 20 are each formed using a silicon (Si) substrate (hereinafter referred to as a "Si substrate"), and the Si substrates are bonded to each other. Alternatively, resonator 10, lower cover 20, and upper cover 30 can each be formed using an SOI (Silicon On Insulator) substrate, which is a laminate of a silicon layer and a silicon oxide film.

[0029] The upper cover 30 extends along the XY plane into a flat plate shape. A flat rectangular recess 31, for example, is formed on its back surface. The recess 31 is surrounded by sidewalls 33 and forms part of the vibration space within which the resonator 10 vibrates. Alternatively, the upper cover 30 may be flat and lack the recess 31. Furthermore, an air gettering layer for absorbing exhaust gas may be formed on the surface of the recess 31 of the upper cover 30 facing the resonator 10.

[0030] The lower cover 20 includes a bottom plate 22 having a rectangular flat plate shape arranged along the XY plane, and a side wall 23 extending from the peripheral edge of the bottom plate 22 in the Z-axis direction, i.e., the stacking direction of the lower cover 20 and the resonator 10. In the lower cover 20, a recess 21 formed by the surface of the bottom plate 22 and the inner surface of the side wall 23 is formed on the surface facing the resonator 10. The recess 21 forms a portion of the vibration space of the resonator 10. Alternatively, the lower cover 20 may have a flat plate shape without the recess 21. Furthermore, an air absorption layer for absorbing exhaust gas may be formed on the surface of the recess 21 of the lower cover 20 on the resonator 10 side.

[0031] Furthermore, the lower cover 20 includes a protrusion 25 formed on the surface of the bottom plate 22. The detailed structure of the protrusion 25 will be described later.

[0032] The upper cover 30 is bonded to the resonator 10 and the lower cover 20 to hermetically seal the vibration space of the resonator 10 and maintain a vacuum state. The vibration space may be filled with a gas such as an inert gas.

[0033] Next, refer to Figure 3 A brief structure of a resonator in a resonance device according to one embodiment will be described. Figure 3 It is briefly shown Figure 2 A top view of the structure of the resonator 10 is shown.

[0034] like Figure 3As shown, the resonator 10 is a MEMS vibrator manufactured using MEMS technology. Figure 3 The resonator 10 vibrates in the XY plane of the orthogonal coordinate system with the out-of-plane bending vibration mode as the main vibration (hereinafter also referred to as the "main mode"). In addition, the resonator 10 is not limited to the resonator using the out-of-plane bending vibration mode. The resonator of the resonator device 1 may also be a resonator using the extended vibration mode, the thickness longitudinal vibration mode, the Lamb wave vibration mode, the in-plane bending vibration mode, or the surface wave vibration mode. These vibrators are used in, for example, timing devices, RF filters, duplexers, ultrasonic transducers, gyroscope sensors, acceleration sensors, etc. In addition, they can also be used for piezoelectric mirrors with actuator functions, piezoelectric gyroscopes, piezoelectric microphones with pressure sensor functions, ultrasonic vibration sensors, etc. Furthermore, they can also be used for electrostatic MEMS elements, electromagnetically driven MEMS elements, and piezoresistive MEMS elements.

[0035] The resonator 10 includes a vibrating portion 110 , a holding portion 140 , and a supporting arm portion 150 .

[0036] The vibration part 110 has a Figure 3 The outline of the rectangle extending from the XY plane in the orthogonal coordinate system of FIG. The vibration part 110 is arranged inside the holding part 140, and a space is formed between the vibration part 110 and the holding part 140 at a predetermined interval. Figure 3 In the example shown, the vibration unit 110 includes an excitation unit 120 composed of four vibration arms 121A to 121D (hereinafter collectively referred to as "vibration arms 121") and a base 130. The number of vibration arms is not limited to four and can be set to any number, for example, one or more. In this embodiment, the excitation unit 120 and the base 130 are integrally formed.

[0037] Vibrating arms 121A, 121B, 121C, and 121D extend in the Y-axis direction and are arranged in this order in parallel at predetermined intervals in the X-axis direction. One end of vibrating arm 121A is a fixed end connected to a front end 131A of a base 130, described later, and the other end of vibrating arm 121A is an open end disposed away from the front end 131A of the base 130. Vibrating arm 121A includes a mass addition portion 122A formed on the open end side and an arm portion 123A extending from the fixed end and connected to the mass addition portion 122A. Similarly, vibrating arms 121B, 121C, and 121D also include mass addition portions 122B, 122C, and 122D and arm portions 123B, 123C, and 123D, respectively. Furthermore, arm portions 123A to 123D each have a width of approximately 30 μm in the X-axis direction and a length of approximately 400 μm in the Y-axis direction, for example.

[0038] In the excitation unit 120 of this embodiment, two vibration arms 121A and 121D are arranged on the outside in the X-axis direction, and two vibration arms 121B and 121C are arranged on the inside. The width of the gap (hereinafter referred to as the "release width") W1 formed between the arm portions 123B and 123C of the two inner vibration arms 121B and 121C is set to be larger than the release width W2 between the arm portions 123A and 123B of the adjacent vibration arms 121A and 121B in the X-axis direction, and the release width W2 between the arm portions 123D and 123C of the adjacent vibration arms 121D and 121C in the X-axis direction. The release width W1 is, for example, approximately 25 μm, and the release width W2 is, for example, approximately 10 μm. By setting the release width W1 larger than the release width W2, the vibration characteristics and durability of the vibration unit 110 are improved. Furthermore, in order to reduce the size of the resonance device 1 , the open width W1 may be set smaller than the open width W2 , or may be set at equal intervals.

[0039] The mass-adding portions 122A to 122D each have mass-adding films 125A to 125D on their respective surfaces. Therefore, the weight per unit length (hereinafter, simply referred to as "weight") of each of the mass-adding portions 122A to 122D is greater than the weight of each of the arm portions 123A to 123D. This allows the vibration portion 110 to be miniaturized and the vibration characteristics to be improved. Furthermore, the mass-adding films 125A to 125D each not only increase the weight of the tip portion of the vibration arms 121A to 121D but also function as so-called frequency-adjusting films, adjusting the resonant frequency of the vibration arms 121A to 121D by shaving off a portion of the film.

[0040] In this embodiment, the width of each of the mass-adding portions 122A to 122D along the X-axis is, for example, approximately 49 μm, which is greater than the width of each of the arm portions 123A to 123D along the X-axis. This further increases the weight of each of the mass-adding portions 122A to 122D. To minimize the size of the resonator 10, the width of each of the mass-adding portions 122A to 122D along the X-axis is preferably at least 1.5 times the width of each of the arm portions 123A to 123D along the X-axis. However, as long as the weight of each of the mass-adding portions 122A to 122D is greater than the weight of each of the arm portions 123A to 123D, the width of each of the mass-adding portions 122A to 122D along the X-axis is not limited to that of this embodiment. The width of each of the mass addition portions 122A to 122D along the X-axis direction may be equal to or smaller than the width of each of the arm portions 123A to 123D along the X-axis direction.

[0041] When viewing the resonator 10 from above (hereinafter simply referred to as "viewed from above"), the mass-adding portions 122A to 122D are each roughly rectangular, with curved corners, such as a so-called R-shape. Similarly, the arms 123A to 123D are each roughly rectangular, with an R-shape near the fixed end connected to the base 130 and near the connection portion with each of the mass-adding portions 122A to 122D. However, the shapes of the mass-adding portions 122A to 122D and the arms 123A to 123D are not limited to those in the present embodiment. For example, the shapes of the mass-adding portions 122A to 122D may each be roughly trapezoidal or L-shaped. Furthermore, the shapes of the arms 123A to 123D may each be roughly trapezoidal. The mass-adding portions 122A to 122D and the arms 123A to 123D may each be formed as a bottomed groove with an opening on either the front or back side, or as a hole with an opening on both the front and back sides. The groove and hole may be spaced apart from the side surface connecting the front and back sides, or may have an opening on the side surface.

[0042] In a plan view, base 130 includes a front end 131A, a rear end 131B, a left end 131C, and a right end 131D. As described above, the fixed ends of the vibrating arms 121A to 121D are connected to front end 131A. Support arm 151 of support arm unit 150 (described later) is connected to rear end 131B.

[0043] The front end 131A, rear end 131B, left end 131C, and right end 131D are each a portion of the outer edge of the base 130. Specifically, the front end 131A and rear end 131B are ends extending in the X-axis direction, and the front end 131A and rear end 131B are disposed opposite each other. The left end 131C and right end 131D are ends extending in the Y-axis direction, and the left end 131C and right end 131D are disposed opposite each other. The ends of the left end 131C are connected to one end of the front end 131A and one end of the rear end 131B, respectively. The ends of the right end 131D are connected to the other end of the front end 131A and the other end of the rear end 131B, respectively.

[0044] In a top view, the base 130 has a generally rectangular shape with the front end 131A and the rear end 131B as long sides and the left end 131C and the right end 131D as short sides. The base 130 is formed to be generally plane-symmetrical with respect to an imaginary plane defined along the perpendicular bisector of each of the front end 131A and the rear end 131B, that is, the center line CL1 in the X-axis direction. In other words, the base 130 can be said to be generally line-symmetrical about the center line CL1. The shape of the base 130 is not limited to Figure 3While the rectangular shape shown, other shapes that are substantially line-symmetrical about centerline CL1 may also be used. For example, base 130 may be shaped like a trapezoid, with one of front end 131A and rear end 131B being longer than the other. Furthermore, at least one of front end 131A, rear end 131B, left end 131C, and right end 131D may be curved or bent.

[0045] Furthermore, the imaginary plane corresponds to the plane of symmetry of the entire vibrating portion 110, and the center line CL1 corresponds to the center line of the entire vibrating portion 110 in the X-axis direction. Therefore, the center line CL1 also passes through the X-axis centers of the vibrating arms 121A to 121D and is located between the vibrating arms 121B and 121C. Specifically, each of the adjacent vibrating arms 121A and 121B is formed symmetrically with each of the adjacent vibrating arms 121D and 121C across the center line CL1.

[0046] In the base 130, the longest distance in the Y-axis direction between the front end 131A and the rear end 131B, that is, the base length, is, for example, about 20 μm. In addition, the longest distance in the X-axis direction between the left end 131C and the right end 131D, that is, the base width, is, for example, about 180 μm. Figure 3 In the example shown, the base length corresponds to the length of the left end portion 131C or the right end portion 131D, and the base width corresponds to the length of the front end portion 131A or the rear end portion 131B.

[0047] The holding portion 140 is configured to hold the vibrating portion 110. More specifically, the holding portion 140 is configured to enable vibration of the vibrating arms 121A to 121D. Specifically, the holding portion 140 is formed to be plane-symmetrical with respect to an imaginary plane defined along the center line CL1. The holding portion 140 has a rectangular frame shape when viewed from above and is arranged to surround the vibrating portion 110 along the XY plane. This frame shape of the holding portion 140 when viewed from above makes it easy to implement the holding portion 140 surrounding the vibrating portion 110.

[0048] The holding portion 140 is not limited to a frame shape and can be disposed around at least a portion of the vibrating portion 110 . For example, the holding portion 140 can be disposed around the vibrating portion 110 to such an extent that it can hold the vibrating portion 110 and can be bonded to the upper cover 30 and the lower cover 20 .

[0049] In this embodiment, the holding portion 140 includes integrally formed frames 141A to 141D. Figure 3As shown, frame 141A is opposed to the open ends of vibration arms 121A to 121D, with its longitudinal direction parallel to the X-axis. Frame 141B is opposed to rear end 131B of base 130, with its longitudinal direction parallel to the X-axis. Frame 141C is opposed to left end 131C of base 130 and vibration arm 121A, with its longitudinal direction parallel to the Y-axis, and is connected at both ends to one end of frame 141A and 141B, respectively. Frame 141D is opposed to right end 131D of base 130 and vibration arm 121D, with its longitudinal direction parallel to the Y-axis, and is connected at both ends to the other ends of frame 141A and 141B, respectively. Frame 141A and frame 141B are opposed to each other in the Y-axis direction with vibration unit 110 interposed therebetween. The frame body 141C and the frame body 141D face each other in the X-axis direction with the vibration unit 110 interposed therebetween.

[0050] The support arm 150 is disposed inside the retaining portion 140 and connects the base 130 and the retaining portion 140. The support arm 150 is not line-symmetrical about the centerline CL1, that is, it is asymmetrical. Specifically, when viewed from above, the support arm 150 includes a single support arm 151. The support arm 151 includes a rear support arm 152.

[0051] The rear support arm 152 extends from the holding portion 140 between the rear end portion 131B of the base 130 and the holding portion 140. Specifically, one end (the left end, or the end on the frame 141C side) of the rear support arm 152 is connected to the frame 141C and extends toward the frame 141D in the X-axis direction. In other words, one end of the support arm 151 is connected to the holding portion 140. Furthermore, the rear support arm 152 bends in the Y-axis direction at the center of the base 130 in the X-axis direction, extends from there along the center line CL1, and is connected to the rear end portion 131B of the base 130. In other words, the other end of the support arm 151 is connected to the rear end portion 131B of the base 130.

[0052] The protrusion 25 protrudes from the recess 21 of the lower cover 20 into the vibration space. When viewed from above, the protrusion 25 is arranged between the arm 123B of the vibration arm 121B and the arm 123C of the vibration arm 121C. The protrusion 25 extends in parallel with the arm 123B and 123C in the Y-axis direction, forming a prism shape. The length of the protrusion 25 in the Y-axis direction is about 240 μm, and the length in the X-axis direction is about 15 μm. In addition, the number of protrusions 25 is not limited to one, and can also be two or more. In this way, by arranging the protrusion 25 between the vibration arm 121B and the vibration arm 121C and protruding from the bottom plate 22 of the recess 21, the rigidity of the lower cover 20 can be improved, and the deflection of the resonator 10 formed on the lower cover 20 and the warping of the lower cover 20 can be suppressed.

[0053] The separation groove 145 is configured to surround the vibrating portion 110 in a plan view. More specifically, the separation groove 145 is configured to surround the vibrating portion 110 and the supporting arm portion 150 disposed inside the holding portion 140. Specifically, the separation groove 145 is a groove extending from the front surface to the back surface of the resonator 10, formed in a predetermined region of the holding portion 140, and having a generally rectangular frame shape in a plan view.

[0054] Next, refer to Figure 4 as well as Figure 5 , and describes the stacked structure and operation of a resonance device according to one embodiment. Figure 4 It is briefly shown Figure 1 FIG. 1 is a cross-sectional view of the stacked structure of the resonator device 1 along the X-axis. Figure 5 It is conceptually shown Figure 1 FIG. 1 is a cross-sectional view of the stacked structure of the resonator device 1 along the Y axis.

[0055] like Figure 4 as well as Figure 5 As shown, in the resonator device 1, the holding portion 140 of the resonator 10 is joined to the side wall 23 of the lower cover 20, and the holding portion 140 of the resonator 10 is further joined to the side wall 33 of the upper cover 30. In this way, the resonator 10 is held between the lower cover 20 and the upper cover 30, and a vibration space is formed by the lower cover 20, the upper cover 30, and the holding portion 140 of the resonator 10 for the vibration portion 110.

[0056] The vibrating portion 110, holding portion 140, and supporting arm portion 150 of the resonator 10 are integrally formed using the same process. In the resonator 10, a metal film E1 is laminated on a Si substrate F2, an example of a substrate. Furthermore, a piezoelectric film F3 is laminated on the metal film E1 to cover the metal film E1, and a metal film E2 is laminated on the piezoelectric film F3. A protective film F5 is laminated on the metal film E2 to cover the metal film E2. In the mass-adding portions 122A to 122D, the mass-adding films 125A to 125D are laminated on the protective film F5, respectively. The outer shapes of the vibrating portion 110, holding portion 140, and supporting arm portion 150 are formed by removing and patterning the laminate composed of the Si substrate F2, metal film E1, piezoelectric film F3, metal film E2, protective film F5, and the like, using, for example, dry etching.

[0057] The Si substrate F2 is formed, for example, from a degenerate n-type silicon (Si) semiconductor with a thickness of approximately 6 μm. It may contain n-type dopants such as phosphorus (P), arsenic (As), and antimony (Sb). The resistance of the degenerate silicon (Si) used in the Si substrate F2 is, for example, less than 1.6 mΩ·cm, and more preferably less than 1.2 mΩ·cm. Furthermore, a silicon oxide layer F21, such as SiO2, is formed on the lower surface of the Si substrate F2 as an example of a temperature characteristic compensation layer. This improves the temperature characteristics.

[0058] In this embodiment, the silicon oxide layer F21 is a layer that has the function of reducing the temperature coefficient of the frequency, or the rate of change per unit temperature, of the vibration unit 110 when the temperature compensation layer is formed on the Si substrate F2, at least at room temperature, compared to a case where the silicon oxide layer F21 is not formed on the Si substrate F2. The inclusion of the silicon oxide layer F21 in the vibration unit 110 can, for example, reduce temperature-related changes in the resonant frequency of the stacked structure formed by the Si substrate F2, the metal films E1 and E2, the piezoelectric film F3, and the silicon oxide layer F21. The silicon oxide layer can be formed on the upper surface of the Si substrate F2, or on both the upper and lower surfaces of the Si substrate F2.

[0059] The silicon oxide layer F21 of the mass adding portions 122A to 122D is preferably formed with a uniform thickness. The term "uniform thickness" means that the thickness of the silicon oxide layer F21 has a thickness within ±20% of the average value.

[0060] The metal films E1 and E2 each include an excitation electrode for exciting the vibration arms 121A to 121D and an extraction electrode for electrically connecting the excitation electrode to an external power supply. The portions of the metal films E1 and E2 that function as excitation electrodes are opposed to each other in the arm portions 123A to 123D of the vibration arms 121A to 121D, with the piezoelectric film F3 interposed therebetween. The portions of the metal films E1 and E2 that function as extraction electrodes are led out from the base 130 to the retaining portion 140, for example, via the support arm portion 150. The metal film E1 is electrically continuous throughout the entire resonator 10. The metal film E2 is electrically separated in the portion formed in the vibration arms 121A and 121D and the portion formed in the vibration arms 121B and 121C. The portion of the metal film E1 that functions as an excitation electrode is also referred to as a lower electrode. The portion of the metal film E2 that functions as an excitation electrode is also referred to as an upper electrode.

[0061] The thickness of the metal films E1 and E2 is, for example, approximately 0.1 μm to 0.2 μm. After forming, the metal films E1 and E2 are patterned into excitation electrodes, extraction electrodes, and the like by etching or other removal processes. The metal films E1 and E2 are formed, for example, from a metal material having a body-centered cubic crystal structure. Specifically, the metal films E1 and E2 are formed using Mo (molybdenum), tungsten (W), or the like. Thus, by using a metal having a body-centered cubic crystal structure as the main component, the metal films E1 and E2 can easily be formed into metal films E1 and E2 suitable for the lower and upper electrodes of the resonator 10.

[0062] In this embodiment, an example is shown in which the resonator 10 includes a metal film E1, but the present invention is not limited to this. Preferably, the Si substrate F2 included in the resonator 10 is not simple silicon (Si), but rather a low-resistance degenerate silicon substrate (hereinafter referred to as a "degenerate silicon substrate"). Thus, the resonator 10 omits the metal film E1, and the degenerate silicon substrate itself can also serve the role of the metal film E1, such as the role of the lower electrode. Therefore, in the collective substrate 100 described later, by sharing the degenerate silicon substrate in adjacent resonator devices, multiple resonator devices can be easily energized simultaneously via the degenerate silicon substrates, i.e., the lower electrodes, of the multiple resonators 10.

[0063] The piezoelectric film F3 is a thin film formed from a type of piezoelectric material that converts electrical energy into mechanical energy. The piezoelectric film F3 expands and contracts in the Y-axis direction, which is the in-plane direction of the XY plane, in response to the electric field generated by the metal films E1 and E2. This expansion and contraction of the piezoelectric film F3 causes the vibrating arms 121A to 121D to move their open ends toward the bottom plate 22 of the lower cover 20 and the bottom plate 32 of the upper cover 30, respectively. This causes the resonator 10 to vibrate in an out-of-plane bending vibration mode.

[0064] The thickness of the piezoelectric film F3 is, for example, about 1 μm, but can also be about 0.2 μm to 2 μm. The piezoelectric film F3 is formed of a material having a crystal structure having a wurtzite hexagonal crystal structure, and can be composed mainly of nitrides or oxides such as aluminum nitride (AlN), scandium aluminum nitride (ScAlN), zinc oxide (ZnO), gallium nitride (GaN), and indium nitride (InN). In addition, scandium aluminum nitride is obtained by replacing part of the aluminum in aluminum nitride with scandium, and scandium can also be replaced with two elements such as magnesium (Mg) and niobium (Nb), or magnesium (Mg) and zirconium (Zr). In this way, the piezoelectric film F3 is composed mainly of a piezoelectric body having a wurtzite hexagonal crystal structure, so that a piezoelectric film F3 suitable for the resonator 10 can be easily realized.

[0065] The protective film F5 protects the metal film E2 from oxidation. Furthermore, as long as the protective film F5 is provided on the upper cover 30 side, it need not be exposed relative to the bottom plate 32 of the upper cover 30. For example, a parasitic capacitance reduction film that reduces the capacitance of the wiring formed in the resonator 10 may be formed to cover the protective film F5. The protective film F5 is formed of, for example, piezoelectric films such as aluminum nitride (AlN), scandium aluminum nitride (ScAlN), zinc oxide (ZnO), gallium nitride (GaN), and indium nitride (InN), as well as insulating films such as silicon nitride (SiN), silicon oxide (SiO2), aluminum oxide (Al2O3), and tantalum pentoxide (Ta2O5). The thickness of the protective film F5 is formed to a length that is less than half the thickness of the piezoelectric film F3, and in this embodiment, is, for example, approximately 0.2 μm. A more preferred thickness of the protective film F5 is approximately one-quarter the thickness of the piezoelectric film F3. Furthermore, when the protective film F5 is formed of a piezoelectric material such as aluminum nitride (AlN), it is preferable to use a piezoelectric material having the same orientation as that of the piezoelectric film F3.

[0066] It is preferable that the protective film F5 of the mass-added portions 122A to 122D be formed with a uniform thickness. The term "uniform thickness" means that the variation in the thickness of the protective film F5 is within ±20% of the average value of the thickness.

[0067] The mass-adding films 125A to 125D constitute the surface of the upper cover 30 side of each of the mass-adding parts 122A to 122D, and correspond to the frequency-adjusting films of each of the vibration arms 121A to 121D. The frequency of the resonator 10 is adjusted by trimming to remove a portion of each of the mass-adding films 125A to 125D. From the perspective of frequency adjustment efficiency, the mass-adding films 125A to 125D are preferably formed of a material having a faster mass reduction rate by etching than that of the protective film F5. The mass reduction rate is represented by the product of the etching rate and the density. The etching rate is the thickness removed per unit time. If the relationship between the mass reduction rates of the protective film F5 and the mass-adding films 125A to 125D is as described above, the relationship between the etching rates is arbitrary. In addition, from the perspective of effectively increasing the weight of the mass-adding parts 122A to 122D, the mass-adding films 125A to 125D are preferably formed of a material with a higher specific gravity. For these reasons, the mass additional films 125A to 125D are formed of a metal material such as molybdenum (Mo), tungsten (W), gold (Au), platinum (Pt), nickel (Ni), aluminum (Al), or titanium (Ti).

[0068] A portion of the upper surface of each of the mass addition films 125A to 125D is removed by trimming during the frequency adjustment process. The trimming of the mass addition films 125A to 125D can be performed, for example, by dry etching using an argon (Ar) ion beam. Since the ion beam can irradiate a wide area, the processing efficiency is excellent. However, since the mass addition films 125A to 125D have an electric charge, there is a possibility that the mass addition films 125A to 125D will be charged. In order to prevent the Coulomb interaction caused by the charging of the mass addition films 125A to 125D, which may cause the vibration orbits of the vibration arms 121A to 121D to change and deteriorate the vibration characteristics of the resonator 10, it is preferable that the mass addition films 125A to 125D be grounded.

[0069] An internal terminal T1' and connecting wires CW2 and CW3 are formed on the protective film F5 of the holding portion 140. The internal terminal T1' is electrically connected to the metal film E1 through through-holes formed in the piezoelectric film F3 and the protective film F5. If the resonator 10 does not include the metal film E1, the internal terminal T1' is electrically connected to the Si substrate F2, which also serves as the metal film E1, through the through-holes.

[0070] The connection wiring CW2 is routed as described below and electrically connected to the portion of the metal film E2 formed in the vibrating arms 121A and 121D. The connection wiring CW3 is routed as described below and electrically connected to the portion of the metal film E2 formed in the vibrating arms 121B and 121C. The internal terminal T1' and the connection wirings CW2 and CW3 are formed of a metal material such as aluminum (Al), germanium (Ge), gold (Au), or tin (Sn).

[0071] The bottom plate 22 and sidewalls 23 of the lower cover 20 are integrally formed from a Si substrate P10. The Si substrate P10 is formed from non-degenerate silicon, and its resistivity is, for example, 10 Ω·cm or more. The Si substrate P10 is exposed inside the recess 21 of the lower cover 20. A silicon oxide layer F21 is formed on the upper surface of the protrusion 25. However, from the perspective of suppressing the charging of the protrusion 25, the Si substrate P10 having a lower resistivity than the silicon oxide layer F21 may be exposed on the upper surface of the protrusion 25, or a conductive layer may be formed.

[0072] The thickness of the lower cover 20 defined in the Z-axis direction is approximately 150 μm, and the depth of the recessed portion 21 defined similarly is approximately 50 μm.

[0073] The bottom plate 32 and side walls 33 of the upper cover 30 are integrally formed from a Si substrate Q10. The surface, back surface, and inner side surfaces of the through-holes of the upper cover 30 are preferably covered with an insulating oxide film Q11, such as a silicon oxide film. The insulating oxide film Q11 is formed on the surface of the Si substrate Q10, for example, by oxidation of the Si substrate Q10 or chemical vapor deposition (CVD). The Si substrate Q10 is exposed inside the recess 31 of the upper cover 30. Furthermore, an air-gettering layer may be formed on the surface of the recess 31 of the upper cover 30 that faces the resonator 10. The air-gettering layer is formed, for example, of titanium (Ti), and absorbs exhaust gases released from the joint 60 described later, thereby suppressing a decrease in the vacuum level of the vibration space. The gettering layer may be formed on the surface of the recess 21 of the lower cover 20 facing the resonator 10 , or may be formed on the surfaces of both the recess 21 of the lower cover 20 and the recess 31 of the upper cover 30 facing the resonator 10 .

[0074] The thickness of the upper cover 30 defined in the Z-axis direction is approximately 150 μm, and the depth of the recessed portion 31 defined similarly is approximately 50 μm.

[0075] External terminals T1, T2, and T3 are formed on the upper surface of the upper cover 30 (the surface opposite to the surface facing the resonator 10). The external terminal T1 is a mounting terminal for grounding the metal film E1 of the resonator 10. The external terminal T2 is a mounting terminal for electrically connecting the metal film E2 of the vibration arms 121A and 121D of the resonator 10 to an external power supply. The external terminal T3 is a mounting terminal for electrically connecting the metal film E2 of the vibration arms 121B and 121C of the resonator 10 to an external power supply. The external terminals T1, T2, and T3 are formed, for example, by plating a metallization layer (base layer) made of chromium (Cr), tungsten (W), or nickel (Ni) with nickel (Ni), gold (Au), silver (Ag), Cu (copper), or the like. In addition, dummy terminals electrically insulated from the resonator 10 may be formed on the upper surface of the upper cover 30 for the purpose of adjusting parasitic capacitance or balancing mechanical strength.

[0076] Through-electrodes V1, V2, and V3 are formed within the sidewall 33 of the upper cover 30. Through-electrode V1 electrically connects the external terminal T1 and the internal terminal T1' via a connection wiring CW1, described later. Furthermore, through-electrode V2 electrically connects the external terminal T2 and the connection wiring CW2, and through-electrode V3 electrically connects the external terminal T3 and the connection wiring CW3. Through-electrodes V1, V2, and V3 are formed by filling through-holes that penetrate the sidewall 33 of the upper cover 30 in the Z-axis direction with a conductive material. Examples of the conductive material used are polysilicon (Poly-Si), copper (Cu), gold (Au), and the like.

[0077] The connection wiring CW1 is formed on the surface of the side wall 33 of the upper cover 30 that faces the resonator 10. The connection wiring CW1 connects the through-electrode V1 and the internal terminal T1'. As described above, the internal terminal T1' is electrically connected to the metal film E1 of the resonator 10, so that the vibrating portion 110 (the excitation portion 120 and the base 130) of the resonator 10 can be energized via the connection wiring CW1. Therefore, during an inspection process, for example, the vibration characteristics of the resonator 10 can be measured from outside the upper cover 30 via the external terminal T1, the through-electrode V1, and the connection wiring CW1. Furthermore, the connection wiring CW1 of this embodiment corresponds to an example of the "first connection portion" of the present invention.

[0078] A joint 60 is formed between the sidewall 33 of the upper cover 30 and the retaining portion 140. The upper cover 30 and the MEMS substrate 50 (the lower cover 20 and the resonator 10) are joined together via this joint 60. The joint 60 is formed in a closed loop shape surrounding the vibrating portion 110 in the XY plane, thereby airtightly sealing the vibration space of the resonator 10 in a vacuum state.

[0079] The bonding portion 60 is conductive and is formed, for example, from a metal film formed by sequentially stacking an aluminum (Al) film, a germanium (Ge) film, and an aluminum (Al) film and eutectic bonding. Alternatively, the bonding portion 60 may be formed from a combination of films appropriately selected from gold (Au), tin (Sn), copper (Cu), titanium (Ti), silicon (Si), and the like. Furthermore, to improve adhesion, the bonding portion 60 may include a metal compound such as titanium nitride (TiN) or tantalum nitride (TaN) between the films.

[0080] Furthermore, the connection wiring CW1 extends to the outer periphery of the lower surface of the upper cover 30 , and the joint portion 60 and the connection wiring CW1 are electrically connected.

[0081] On the upper surface of the MEMS substrate 50 (lower cover 20 and resonator 10), the bonding portion 60 is disposed at a predetermined distance, for example, approximately 20 μm, from the outer edge. This prevents product defects in the resonator device 1, such as protrusions (burrs) and edge collapse, that might otherwise occur if the bonding portion 60 were not spaced at the predetermined distance.

[0082] In the holder 140, a separation groove 145 is formed, extending from the protective film F5 formed on the surface to the silicon oxide layer F21 on the lower surface of the Si substrate F2. As described above, the separation groove 145 is formed so as to surround the vibrating portion 110 when viewed from above. Therefore, the separation groove 145 separates the outside of the resonator 10 from the vibrating portion 110, and the conductive path from the outside of the resonator 10 to the vibrating portion 110 via the holder 140 is cut off before bonding. This can suppress the propagation of noise to the vibrating portion 110 via the holder 140, allowing, for example, the resonant frequency to be adjusted with high accuracy during frequency adjustment.

[0083] In this embodiment, external terminal T1 is grounded, and alternating voltages of opposite phases are applied to external terminals T2 and T3. Consequently, the electric field formed on the piezoelectric film F3 of the vibrating arms 121A and 121D and the electric field formed on the piezoelectric film F3 of the vibrating arms 121B and 121C are in opposite phases. Consequently, the outer vibrating arms 121A and 121D and the inner vibrating arms 121B and 121C displace in opposite directions.

[0084] For example, Figure 4 As shown, when the mass addition portions 122A, 122D and arm portions 123A, 123D of the vibration arms 121A, 121D, respectively, displace toward the inner surface of the upper cover 30, the mass addition portions 122B, 122C and arm portions 123B, 123C of the vibration arms 121B, 121C, respectively, displace toward the inner surface of the lower cover 20. Although not shown in the figure, conversely, when the mass addition portions 122A, 122D and arm portions 123A, 123D of the vibration arms 121A, 121D, respectively, displace toward the inner surface of the lower cover 20, the mass addition portions 122B, 122C and arm portions 123B, 123C of the vibration arms 121B, 121C, respectively, displace toward the inner surface of the upper cover 30. As a result, at least two of the four vibration arms 121A to 121D bend out-of-plane with different phases.

[0085] Thus, between adjacent vibration arms 121A and 121B, vibration arms 121A and 121B vibrate in opposite vertical directions about a central axis r1 extending in the Y-axis direction. Furthermore, between adjacent vibration arms 121C and 121D, vibration arms 121C and 121D vibrate in opposite vertical directions about a central axis r2 extending in the Y-axis direction. This generates torsional moments in opposite directions about central axes r1 and r2, causing flexural vibration in the vibration portion 110. The maximum amplitude of vibration arms 121A to 121D is approximately 50 μm, and the amplitude during normal operation is approximately 10 μm.

[0086] Next, refer to Figure 6 A resonator and its surrounding wiring in a resonant device according to one embodiment will be described. Figure 6 It is briefly shown Figures 1 to 5 The diagram shows a top view of the resonator 10 and its surrounding wiring.

[0087] like Figure 6 As shown, internal terminals T1', T2', and T3' are formed on the protective film F5 of the resonator 10 in the region inside the separation groove 145. As described above, the internal terminal T1' is electrically connected to the connection wiring CW1 formed on the upper cover 30, and is also electrically connected to the metal film E1 embedded in the resonator 10 via a through-hole.

[0088] The internal terminal T2' is a terminal for electrically connecting the through-electrode V2 formed on the upper cover 30 and the connection wiring CW2 formed on the resonator 10. The connection wiring CW2 extends from the internal terminal T2' and is routed, electrically connecting to the metal film E2 formed on the arm portion 123B of the vibrating arm 121B and the metal film E2 formed on the arm portion 123C of the vibrating arm 121C. The internal terminal T3' is a terminal for electrically connecting the through-electrode V3 formed on the upper cover 30 and the connection wiring CW3 formed on the resonator 10. The connection wiring CW3 extends from the internal terminal T3' and is routed, electrically connecting to the metal film E2 formed on the arm portion 123A of the vibrating arm 121A and the metal film E2 formed on the arm portion 123D of the vibrating arm 121D.

[0089] The internal terminals T2 ′, T3 ′ and the connection wirings CW2 , CW3 are formed of a metal material such as aluminum (Al), germanium (Ge), gold (Au), or tin (Sn), similarly to the internal terminal T1 ′ and the connection wiring CW1 .

[0090] The annular joint 60 formed on the resonator 10 includes a connecting member 65. In other words, the connecting member 65 is integrally formed with the joint 60 and electrically connected to the joint 60. The connecting member 65 is formed, for example, at each of the four corners of the joint 60, extending to the outer edge of the resonator 10 when viewed from above. This allows electrical conduction between the vibrating portions 110 of the plurality of resonator devices 1 in the aggregate substrate 100 (described later) via the joint 60 and the connecting member 65. Therefore, during an inspection process, for example, the vibration characteristics of the plurality of resonators 10 can be measured simultaneously via the connection wiring CW1, the joint 60, and the connecting member 65, thereby improving the productivity of the resonator devices 1.

[0091] In this embodiment, the example in which the connecting member 65 is electrically connected to the corner of the joint 60 is shown, but the present invention is not limited to this. The connecting member 65 may be connected to the long side or short side of the substantially rectangular joint 60 in plan view and extend to the outer edge of the resonator 10. The number of connecting members 65 is not limited to four; at least one connection member is sufficient.

[0092] The separation groove 145 formed so as to surround the vibration part 110 in a plan view is arranged in a region between the outer edge of the resonator 10 and the vibration part 110. This can easily suppress the propagation of noise from the outer edge of the resonator 10 to the vibration part 110.

[0093] More specifically, when viewed from above, the separation groove 145 is arranged along the inner circumference of the joint 60. This makes it possible to easily form the separation groove 145 that separates the exterior of the resonator 10 from the vibrating portion 110 and cuts off the conductive path from the exterior of the resonator 10 to the vibrating portion 110 via the holding portion 140.

[0094] Next, refer to Figure 7 A description will be given of a stacked structure of connecting members in a resonance device according to one embodiment. Figure 7 It is briefly shown Figure 6 An enlarged cross-sectional view of the stacked structure of the connecting member 65 is shown.

[0095] like Figure 7 As shown, the joint 60 extends from the resonator 10 (MEMS substrate 50 ) side to the upper cover 30 side and includes, for example, a first metal layer 61 , a second metal layer 62 , and a third metal layer 63 .

[0096] The first metal layer 61 is, for example, a metal layer mainly composed of aluminum (Al), and the material of the first metal layer 61 is aluminum (Al), aluminum-copper alloy (AlCu alloy), or aluminum-silicon-copper alloy (AlSiCu alloy). The second metal layer 62 is, for example, a metal layer of germanium (Ge). Figure 7 In the example shown, the first metal layer 61 and the second metal layer 62 are described as separate layers, but in reality, their interface forms a eutectic bond. Specifically, the first metal layer 61 and the second metal layer 62 are composed of a eutectic alloy of metals primarily composed of aluminum (Al) and germanium (Ge). The third metal layer 63 is, for example, a metal layer primarily composed of aluminum (Al). The material of the third metal layer 63 is aluminum (Al), an aluminum-copper alloy (AlCu alloy), or an aluminum-silicon-copper alloy (AlSiCu alloy).

[0097] The connecting member 65 is formed integrally with the bonding portion 60. That is, the connecting member 65 is configured to include a first metal layer 61, a second metal layer 62, and a third metal layer 63, similarly to the bonding portion 60.

[0098] The connecting member 65 is formed on the surface of the MEMS substrate 50 (the lower cover 20 and the resonator 10) facing the upper cover 30 (at Figure 7 Furthermore, the connecting member 65 is formed on the surface of the upper cover 30 that faces the MEMS substrate 50 (the lower cover 20 and the resonator 10) (the surface of the upper cover 30 that faces the MEMS substrate 50). Figure 7 The connecting members 65 extend from the middle and lower surfaces to the outer edges. Thus, in the aggregate substrate 100 described later, by connecting adjacent connecting members 65, the spaces between the plurality of resonant devices 1 can be sealed. Consequently, it is possible to prevent a chemical solution, etc., from intruding into the gaps between the resonant devices 1 in the aggregate substrate 100.

[0099] <Collection substrate>

[0100] Next, refer to Figure 8 as well as Figure 9 A brief structure of an aggregate substrate according to one embodiment will be described. Figure 8 This is an exploded perspective view schematically showing the appearance of the assembly substrate 100 in one embodiment. Figure 9 It is magnified Figure 8 A partial enlarged view of area A is shown.

[0101] The collective substrate 100 of this embodiment is a substrate for manufacturing the above-mentioned resonant device 1. Figure 8 As shown, the collective substrate 100 includes an upper substrate 13 and a lower substrate 14. The upper substrate 13 and the lower substrate 14 each have a circular shape when viewed from above. The lower substrate 14 includes a plurality of resonators 10. As described above, the Si substrate F2 having the plurality of resonators 10 may also be a degenerate silicon substrate. The upper substrate 13 is configured so that its lower surface is opposite to the lower substrate 14 and the plurality of resonators 10 are sandwiched therebetween. In addition, the lower substrate 14 of this embodiment is equivalent to an example of the "first substrate" of the present invention, and the upper substrate 13 of this embodiment is equivalent to an example of the "second substrate" of the present invention.

[0102] like Figure 9 As shown, a plurality of devices DE and a plurality of joints 60 are formed on the upper surface of the lower substrate 14. Each device DE corresponds to the main part of the above-mentioned resonator 10, such as the vibrating part 110 and the supporting arm part 150 arranged on the inner side of the separation groove 145. Each joint 60 is provided in the region of the holding part 140 of the resonator 10. In addition, each joint 60 includes a connecting part 65 at each corner of the rectangle. The group of devices DE and joints 60 are arranged in an array on the entire upper surface of the lower substrate 14. Specifically, in the row direction ( Figure 9 Along the Y axis) and the column direction ( Figure 9 A plurality of such groups are arranged at prescribed intervals in the direction along the X-axis.

[0103] Figure 9 The dividing lines LN1 and LN2 shown are lines, also called scribe lines, for dividing the assembly substrate 100 , i.e., the upper substrate 13 and the lower substrate 14 , into a plurality of resonator devices 1 by cutting or the like. The width of the dividing lines LN1 and LN2 is, for example, 5 μm to 20 μm.

[0104] Each connecting member 65 extends beyond the dividing lines LN1 and LN2. That is, the connecting member 65 of a particular joint 60 is connected to the connecting members 65 of adjacent joints 60 whose corners face each other. As a result, the joints 60 are electrically connected to each other via the connecting members 65.

[0105] <Method for manufacturing MEMS devices>

[0106] Next, a method for manufacturing a resonance device according to one embodiment will be described. Figure 10 This is a flowchart showing a method for manufacturing the resonance device 1 according to one embodiment.

[0107] like Figure 10 As shown, first, the upper substrate 13 corresponding to the upper cover 30 of the resonance device 1 is prepared ( S301 ).

[0108] The upper substrate 13 is formed using a Si substrate. Specifically, the upper substrate 13 is formed by Figure 4 A Si substrate Q10 having a predetermined thickness is formed as shown. The front and back surfaces (the surface facing the resonator 10) of the Si substrate Q10, as well as the side surfaces of the through electrodes V1, V2, and V3, are covered with an insulating oxide film Q11. The insulating oxide film Q11 is formed on the surface of the Si substrate Q10 by, for example, oxidation of the surface of the Si substrate Q10 or chemical vapor deposition (CVD).

[0109] A plurality of external terminals T1, T2, and T3 are formed on the upper surface of the upper substrate 13. The external terminals T1, T2, and T3 are formed by plating a metallization layer (base layer) made of, for example, chromium (Cr), tungsten (W), or nickel (Ni) with nickel (Ni), gold (Au), silver (Ag), or copper (Cu).

[0110] in addition, Figure 4 The through electrodes V2, V3 and Figure 5 The through-electrode V1 shown is formed by filling a conductive material in a through-hole formed in the upper substrate 13. The conductive material used for filling is, for example, impurity-doped polysilicon (Poly-Si), copper (Cu), gold (Au), or impurity-doped single crystal silicon.

[0111] On the other hand, a connection wiring CW1 electrically connected to the bonding portion 60 is formed on the lower surface of the upper substrate 13. The connection wiring CW1 is formed on the lower surface of the upper substrate 13 by patterning a metal material such as aluminum (Al), germanium (Ge), gold (Au), or tin (Sn).

[0112] Next, the lower substrate 14 corresponding to the MEMS substrate 50 (the resonator 10 and the lower cover 20 ) of the resonator device 1 is prepared ( S302 ).

[0113] The lower substrate 14 is formed by bonding Si substrates to each other. Alternatively, the lower substrate 14 may be formed using an SOI substrate. Figure 4As shown, the lower substrate 14 includes a Si substrate P10 and a Si substrate F2.

[0114] The metal film E1, the piezoelectric film F3, the metal film E2 and the protective film F5 are stacked on the upper surface of the Si substrate F2. The mass addition films 125A to 125D are stacked on the protective film F5 and along the Figure 9 The joints 60 are formed at predetermined intervals along the dividing lines LN1 and LN2 shown. The joints 60 include connecting members 65 that connect adjacent joints 60. The outer shapes of the vibrating portion 110, the holding portion 140, the supporting arm portion 150, and the separation groove 145 of the resonator 10 are formed by removing and patterning the laminated body using, for example, dry etching.

[0115] In addition, on the protective film F5, in addition to the bonding portion 60, Figure 6 The internal terminals T1', T2', T3' and the connecting wires CW2, CW3 shown are made of the same metal as the bonding portion 60, thereby simplifying the manufacturing process.

[0116] In this embodiment, an example is shown in which the joint 60, the internal terminals T1', T2', T3', and the connecting wirings CW2 and CW3 are formed on the upper surface of the lower substrate 14, but the present invention is not limited to this. For example, at least one of the joint 60, the internal terminals T1', T2', T3', and the connecting wirings CW2 and CW3 may be formed on the lower surface of the upper substrate 13. In addition, when the joint 60 is composed of multiple materials, a portion of the material of the joint 60, such as germanium (Ge), may be formed on the lower surface of the upper substrate 13, and the remaining material of the joint 60, such as aluminum (Al), may be formed on the upper surface of the lower substrate 14. Similarly, when the internal terminals T1', T2', T3' and the connecting wirings CW2, CW3 are composed of multiple materials, a portion of the material of the internal terminals T1', T2', T3' and the connecting wirings CW2, CW3 can be formed on the lower surface side of the upper substrate 13, and the remaining material of the internal terminals T1', T2', T3' and the connecting wirings CW2, CW3 can be formed on the upper surface side of the lower substrate 14.

[0117] In addition, in this embodiment, an example is shown in which the upper substrate 13 is prepared in step S301 and the lower substrate 14 is prepared in step S302, but the present invention is not limited to this. For example, the order may be reversed, and the upper substrate 13 may be prepared after the lower substrate 14 is prepared, or the preparation of the upper substrate 13 and the preparation of the lower substrate 14 may be performed in parallel.

[0118] Next, the upper substrate 13 prepared in step S301 and the lower substrate 14 prepared in step S302 are bonded together ( S303 ).

[0119] Specifically, the lower surface of the upper substrate 13 and the upper surface of the lower substrate 14 are eutectic-bonded via the bonding portion 60. For example, Figure 5 As shown, the positions of the upper substrate 13 and the lower substrate 14 are aligned so that the connection wiring CW1 formed on the upper substrate 13 and the internal terminal T1' formed on the lower substrate 14 are in contact. After the alignment, the upper substrate 13 and the lower substrate 14 are clamped by a heater or the like, and a heating treatment for eutectic bonding is performed. The temperature in the heating treatment for eutectic bonding is above the eutectic temperature, for example, above 424°C, and the heating time is, for example, about 10 minutes to about 20 minutes. During heating, the upper substrate 13 and the lower substrate 14 are pressed under a pressure of, for example, about 5 MPa to about 25 MPa. In this way, the bonding portion 60 eutectically bonds the lower surface of the upper substrate 13 and the upper surface of the lower substrate 14.

[0120] Next, the upper substrate 13 and the lower substrate 14 are divided along the dividing lines LN1 and LN2 ( S304 ).

[0121] The upper substrate 13 and the lower substrate 14 may be cut by cutting the upper substrate 13 and the lower substrate 14 with a dicing saw, or by using a stealth dicing technique in which a laser is focused to form a modified layer inside the substrate.

[0122] In step S304 , the upper substrate 13 and the lower substrate 14 are divided along dividing lines LN1 and LN2 , thereby being singulated (chipped) into individual resonant devices 1 each including an upper cover 30 and a MEMS substrate 50 (a lower cover 20 and a resonator 10 ).

[0123] As described above, the connecting members 65 extending beyond the dividing lines LN1 and LN2 are cut along with the division of the upper substrate 13 and the lower substrate 14. As a result, the connecting members 65 extend to the outer edge of the resonator 10 of each resonator device 1.

[0124] Next, a modification of the above-mentioned embodiment will be described. Figures 1 to 10 The same or similar structures are marked with the same or similar reference numerals, and their descriptions are appropriately omitted. In addition, the same effects brought about by the same structures are not mentioned one by one.

[0125] (Variation)

[0126] Figure 11This is a plan view schematically showing a resonator 10A and its surrounding wiring of a resonator device 1A in a modified example of one embodiment. Figure 12 It is briefly shown Figure 11 FIG. 2 is an enlarged cross-sectional view of the stacked structure of the connecting member 65A shown.

[0127] like Figure 11 As shown, the resonator 10A of the resonator device 1A has a separation slot 145A. The separation slot 145A and Figure 6 The separation groove 145 shown in the figure also has a substantially rectangular frame shape in a plan view and is formed so as to surround the vibration part 110 of the resonator 10A. On the other hand, the separation groove 145A is formed in the holding part 140 and is aligned with the support part 140. Figure 6 The separating groove 145 shown is arranged in a different region. That is, in a plan view, the separating groove 145A is arranged along the outer periphery of the joint 60. This makes it possible to easily form the separating groove 145A that separates the outside of the resonator 10A from the vibrating portion 110 and cuts off the conductive path from the outside of the resonator 10A to the vibrating portion 110 via the holding portion 140.

[0128] The joint 60 of the resonator device 1A is formed in a ring shape on the resonator 10A and includes a connecting member 65A. The connecting member 65A is connected to Figure 6 The illustrated connecting member 65 is similarly formed at each of the four corners of the joint 60 .

[0129] On the other hand, Figure 12 As shown in FIG. 1 , the connecting member 65A is formed integrally with the second metal layer 62 and the third metal layer 63 of the joint 60. Figure 7 The illustrated connecting member 65 is different and does not include the first metal layer 61 .

[0130] The resonator 10A has a separation groove 145A formed in the region between the joint 60 and the outer edge. Therefore, the connection member 65A is formed on the surface of the upper cover 30 facing the MEMS substrate 50 (lower cover 20 and resonator 10) (at Figure 12 middle and lower surface) extending to the outer edge.

[0131] The above describes an exemplary embodiment of the present invention. In a resonant device according to one embodiment, there is an upper cover, which is configured to be opposite to the MEMS substrate (lower cover and resonator) and sandwich the resonator in the middle, and includes a connection wiring electrically connected to the vibration part. As a result, the vibration part (excitation part and base part) of the resonator can be energized via the connection wiring. Therefore, for example, in the inspection process, the vibration characteristics of the resonator can be measured from the outside of the upper cover via the external terminal, the through electrode and the connection wiring. In addition, the resonator also has a separation groove formed to surround the vibration part when viewed from above. Thus, the outside of the resonator and the vibration part are separated by the separation groove, and the conductive path from the outside of the resonator to the vibration part via the holding part is cut off before joining. Therefore, the propagation of noise to the vibration part via the holding part can be suppressed, for example, the resonant frequency can be adjusted with higher accuracy during frequency adjustment.

[0132] The resonant device further comprises: a joint portion that joins the upper cover and the MEMS substrate (the lower cover and the resonator) to seal the vibration space of the resonator, the joint portion being conductive and electrically connected to the connection wiring; and a connecting member that is electrically connected to the joint portion and extends to the outer edge of the resonator when viewed from above. Thus, in the assembled substrate, the vibrating portions of the multiple resonant devices can be electrically connected via the joint portion and the connecting member. Therefore, for example, during an inspection process, the vibration characteristics of multiple resonators can be measured simultaneously via the connection wiring, the joint portion, and the connecting member, thereby improving the productivity of the resonant device.

[0133] Furthermore, in the aforementioned resonant device, the connecting member extends to the outer edge of both the surface of the MEMS substrate (lower cover and resonator) facing the upper cover and the surface of the upper cover facing the MEMS substrate (lower cover and resonator). This allows the spaces between the multiple resonant devices in the aggregate substrate to be sealed by connecting adjacent connecting members. This prevents the intrusion of chemicals, etc., into the gaps between the resonant devices in the aggregate substrate.

[0134] Furthermore, in the resonator device described above, the separation groove is disposed on the outer periphery of the joint portion in a plan view. This facilitates the formation of the separation groove, which separates the vibrating portion from the exterior of the resonator and cuts off the conductive path from the exterior of the resonator to the vibrating portion via the retaining portion.

[0135] In the resonator device described above, the separation groove is disposed on the inner periphery of the joint portion when viewed from above. This facilitates the formation of the separation groove, which separates the vibrating portion from the exterior of the resonator and cuts off the conductive path from the exterior of the resonator to the vibrating portion via the retaining portion.

[0136] In the above-described resonator device, the separation groove is disposed between the outer edge of the resonator and the vibrating portion in a plan view, thereby easily suppressing the propagation of noise from the outer edge of the resonator to the vibrating portion.

[0137] Furthermore, in the aforementioned resonant device, the resonator 10 further includes a degenerate silicon substrate. This eliminates the need for a metal film in the resonator, allowing the degenerate silicon substrate itself to serve as a metal film, for example, as a lower electrode. Therefore, by sharing the degenerate silicon substrate in adjacent resonant devices in the assembly substrate, multiple resonant devices can be easily energized simultaneously via their degenerate silicon substrates, i.e., their lower electrodes.

[0138] In addition, in an aggregate substrate according to one embodiment, an upper substrate is provided, which is arranged to be opposite to the lower substrate and sandwich a plurality of resonators therebetween, and includes a plurality of connection wirings electrically connected to the vibration parts of each of the plurality of resonators. Thus, the vibration parts (excitation parts and base parts) of the resonators can be energized via the connection wirings. Therefore, for example, in an inspection process, the vibration characteristics of the resonators can be measured from the outside of the upper substrate via external terminals, through electrodes, and connection wirings. In addition, each of the plurality of resonators also has a separation groove formed to surround the vibration part when viewed from above. Thus, the outside of the resonator and the vibration part are separated by the separation groove, and the conductive path from the outside of the resonator to the vibration part via the retaining part is cut off before joining. Therefore, the propagation of noise to the vibration part via the retaining part can be suppressed, and for example, the resonant frequency can be adjusted with higher accuracy during frequency adjustment.

[0139] The aforementioned aggregate substrate further comprises: a plurality of joints, each of which joins the lower substrate and the upper substrate to seal the vibration space of the resonator; the plurality of joints being conductive and electrically connected to each of the plurality of connection wirings; and a connecting member electrically connected to each of the plurality of joints and extending beyond the dividing line used to separate the plurality of resonant devices when viewed from above. Thus, in the aggregate substrate, the vibrating portions of the plurality of resonant devices can be electrically connected via the joints and the connecting member. Therefore, for example, during an inspection process, the vibration characteristics of the plurality of resonators can be measured simultaneously via the connection wirings, joints, and connecting member, thereby improving the productivity of the resonant devices.

[0140] Furthermore, in the aforementioned aggregate substrate, the connecting member extends beyond the dividing line on both the surface of the lower substrate facing the upper substrate and the surface of the upper substrate facing the lower substrate. This allows adjacent connecting members to be connected in aggregate substrate 100, sealing the spaces between the multiple resonant devices. This prevents the intrusion of chemicals and the like into the gaps between the resonant devices in the aggregate substrate.

[0141] Furthermore, in the aforementioned collective substrate, the multiple resonators further comprise a degenerate silicon substrate. This eliminates the need for a metal film in the resonators, allowing the degenerate silicon substrate itself to serve as a metal film, such as a lower electrode. Consequently, by sharing the degenerate silicon substrate between adjacent resonator devices in the collective substrate, multiple resonator devices can be easily energized simultaneously via the degenerate silicon substrates, i.e., the lower electrodes, of the multiple resonators.

[0142] In addition, a method for manufacturing a resonant device according to one embodiment includes preparing a lower substrate and an upper substrate. The lower substrate includes a plurality of resonators, each of which has a vibrating portion and a retaining portion configured to retain the vibrating portion. The upper substrate is positioned opposite the lower substrate, sandwiching the plurality of resonators therebetween, and includes a plurality of connection wirings electrically connected to the vibrating portions of each of the plurality of resonators. This allows the vibrating portions (excitation portion and base portion) of the resonators to be energized via the connection wirings. Therefore, for example, during an inspection process, the vibration characteristics of the resonators can be measured from the outside of the upper substrate via the external terminals, through-electrodes, and connection wirings. Furthermore, each of the plurality of resonators further includes a separation groove formed to surround the vibrating portion when viewed from above. The separation groove separates the vibrating portion from the outside of the resonator, and the conductive path from the outside of the resonator to the vibrating portion via the retaining portion is cut off before bonding. This can suppress the propagation of noise to the vibrating portion via the retaining portion, enabling, for example, high-precision adjustment of the resonant frequency during frequency adjustment.

[0143] In addition, the embodiment described above is for easy understanding of the content of the present invention, and is not for limiting the content of the present invention. The present invention can be changed / improved without departing from its purport, and its equivalents are also included in the present invention. That is, as long as those skilled in the art have the features of the present invention by appropriately applying design changes to the structure obtained by the embodiment and / or modification, it is also included in the scope of the present invention. For example, the various elements and their configuration, materials, conditions, shapes, sizes, etc. possessed by the embodiment and / or modification are not limited to the content shown in the examples and can be appropriately changed. In addition, the embodiment and modification are illustrative, and of course, partial replacement or combination of the structures shown in different embodiments and / or modifications can be carried out, and these structures are included in the scope of the present invention as long as they include the features of the present invention.

[0144] Description of Reference Numerals

[0145] 1, 1A…resonant device; 10, 10A…resonator; 13…upper substrate; 14…lower substrate; 20…lower cover; 21…recess; 22…bottom plate; 23…side wall; 25…protrusion; 30…upper cover; 31…recess; 32…bottom plate; 33…side wall; 50…MEMS substrate; 60…joint portion; 61…first metal layer; 62…second metal layer; 63…third metal layer; 65, 65A…connecting member 100…collective substrate; 110…vibration portion; 120…excitation portion; 121, 121A, 121B, 121C, 121D…vibration arm; 122A, 122B, 122C, 122D…mass addition portion; 123A, 123B, 123C, 123D…arm portion; 125A, 125B, 125C, 125D…mass addition film; 130…base portion; 131A…front end portion; 131 B…rear end; 131C…left end; 131D…right end; 140…holding portion; 141A, 141B, 141C, 141D…frame; 145, 145A…separation slot; 150…support arm; 151…support arm; 152…support rear arm; CL1…center line; CW1, CW2, CW3…connecting wiring; DE…device; E1, E2…metal film; F2…Si substrate; F3…pressing Electrical film; F5…protective film; F21…silicon oxide layer; LN1, LN2…dividing line; P10…Si substrate; Q10…Si substrate; Q11…insulating oxide film; r1, r2…center axis; S301, S302, S303, S304…process; T1, T2, T3…external terminal; T1', T2', T3'…internal terminal; V1, V2, V3…through electrode; W1, W2…release width.

Claims

1. A resonant device comprising: The first substrate includes a resonator having a vibrating portion and a holding portion, wherein: The holding portion is configured to hold the vibration portion; and The second substrate is arranged to face the first substrate with the resonator interposed therebetween and includes a first connection portion electrically connected to the vibration portion. The resonator further includes a separation groove formed so as to surround the vibration portion and the support arm portion in a plan view.

2. The resonant device according to claim 1, wherein Also features: a joint portion for joining the first substrate and the second substrate to seal the vibration space of the resonator, the joint portion being conductive and electrically connected to the first connecting portion; as well as The second connection portion is electrically connected to the bonding portion and extends to the outer edge of the resonator in a plan view.

3. The resonant device according to claim 2, wherein The second connection portion extends to an outer edge of a surface of the first substrate facing the second substrate and a surface of the second substrate facing the first substrate.

4. The resonant device according to claim 2, wherein The separation groove is arranged on the outer periphery of the joining portion in a plan view.

5. The resonant device according to claim 3, wherein The separation groove is arranged on the outer periphery of the joining portion in a plan view.

6. The resonant device according to claim 2, wherein The separation groove is arranged on the inner periphery of the joining portion in a plan view.

7. The resonant device according to claim 3, wherein The separation groove is arranged on the inner periphery of the joining portion in a plan view.

8. The resonant device according to any one of claims 1 to 7, wherein: The separation groove is arranged between the outer edge of the resonator and the vibrating portion in a plan view.

9. The resonant device according to any one of claims 1 to 7, wherein: The resonator further includes a degenerate silicon substrate.

10. The resonant device according to claim 8, wherein The resonator further includes a degenerate silicon substrate.

11. A collective substrate for manufacturing a resonant device, comprising: The first substrate includes a plurality of resonators, each of which has a vibrating portion and a holding portion, wherein: The holding portion is configured to hold the vibration portion; and The second substrate is arranged to face the first substrate with the plurality of resonators sandwiched therebetween, and includes a plurality of first connection portions electrically connected to the vibration portions of the respective resonators. Each of the plurality of resonators further includes a separation groove formed so as to surround the vibration portion and the support arm portion in a plan view.

12. The collective substrate according to claim 11, wherein: Also features: a plurality of joint portions, each of which joins the first substrate and the second substrate to seal the vibration space of the resonator, and having conductivity and electrically connected to each of the plurality of first connecting portions; as well as The second connection portion is electrically connected to each of the plurality of connection portions and extends beyond a dividing line for dividing the resonant device into a plurality of resonant devices in a plan view.

13. The collective substrate according to claim 12, wherein: The second connection portion extends beyond the dividing line on a surface of the first substrate facing the second substrate and a surface of the second substrate facing the first substrate.

14. The collective substrate according to any one of claims 11 to 13, wherein: The plurality of resonators further include a degenerate silicon substrate.

15. A method for manufacturing a resonant device, comprising: The step of preparing a first substrate and a second substrate, wherein the first substrate includes a plurality of resonators, each resonator having a vibrating portion and a holding portion configured to hold the vibrating portion, and the second substrate is arranged to face the first substrate with the plurality of resonators sandwiched therebetween, and includes a plurality of first connecting portions electrically connected to the vibrating portions of each of the plurality of resonators; a step of bonding the first substrate and the second substrate; and a step of dividing the first substrate and the second substrate along a dividing line for dividing the first substrate and the second substrate into a plurality of the resonant devices; Each of the plurality of resonators further includes a separation groove formed so as to surround the vibration portion and the support arm portion in a plan view.

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