Transducer and method for manufacturing transducer

Abstract

The invention provides a transducer and a method for manufacturing the transducer, wherein a gap between a vibration part with a piezoelectric element and the periphery can be properly ensured. A transducer according to one embodiment of the present invention is provided with: a support substrate having a first cavity; a vibration device; and a cover body which has a second cavity and is bonded to the vibration device by means of an adhesive. The vibration device includes a first frame portion and a vibration portion, a portion of the vibration portion is connected to the first frame portion, a portion of the vibration portion other than a portion of the vibration portion connected to the first frame portion is separated from the first frame portion through a slit, the cover includes a second frame portion, the first cavity and the second cavity communicate with each other through the slit, and a convex portion is formed on the first joining surface. A first step recessed from the first joining surface toward a side opposite to the cover body is formed on an inner surface of the first frame portion facing the slit.

Description

Technical Field

[0001] The present disclosure relates to a transducer and a method for manufacturing the transducer. Background Art

[0002] Patent document 1 describes a transducer, which includes: a membrane support portion having a cavity, a cantilever-type vibration membrane, and a piezoelectric element formed on the vibration membrane. In the transducer of Patent document 1, the membrane support portion surrounds the vibration membrane and is connected to one side of the vibration membrane. Gaps are formed between the remaining three sides of the vibration membrane and the membrane support portion.

[0003] [Background Technology Literature]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2021-52305 Summary of the invention

[0006] [summary]

[0007] In the transducer of Patent Document 1, when a driving voltage is applied to the piezoelectric element, the vibrating membrane repeatedly shifts upward and downward alternately. This vibration causes the air around the vibrating membrane to vibrate, and the vibration of the air is output as sound waves. In this case, if the gap between the vibrating membrane and the membrane support portion surrounding the vibrating membrane cannot be properly ensured, the sound characteristics may be affected.

[0008] The present disclosure provides a transducer capable of appropriately ensuring a gap between a vibrating portion having a piezoelectric element and its surroundings, and a method for manufacturing the transducer.

[0009] The transducer of one side of the present disclosure comprises: a supporting substrate having a first cavity; a vibrating device supported by the supporting substrate; and a cover having a second cavity and joined to the vibrating device by an adhesive; and the vibrating device comprises: a first frame portion, which surrounds the first cavity when viewed from the cover and has a first joining surface joined to the cover by the adhesive; and a vibrating portion, which is opposite to the first cavity and has a piezoelectric element; and a portion of the vibrating portion is connected to the first frame portion, and when viewed from the joining direction of the vibrating device and the cover, the vibrating portion The portion except the connection portion with the first frame portion is separated from the first frame portion by a slit that passes through the vibration device along the bonding direction, the cover body has a second frame portion, the second frame portion surrounds the second cavity and includes a second bonding surface bonded to the first bonding surface by the adhesive, the first cavity and the second cavity are connected through the slit, a convex portion protruding toward the second bonding surface is formed on the first bonding surface, and a first step difference is formed on the inner surface of the first frame portion facing the slit, which is recessed from the first bonding surface toward the side opposite to the cover body.

[0010] Another example of a transducer of one side of the present disclosure comprises: a supporting substrate having a first cavity; a vibrating device supported by the supporting substrate; and a cover having a second cavity and bonded to the vibrating device by an adhesive; and the vibrating device comprises: a first frame portion, which surrounds the first cavity when viewed from the cover, and has a first bonding surface bonded to the cover by the adhesive; and a vibrating portion, which faces the first cavity and has a piezoelectric element; and a portion of the vibrating portion is connected to the first frame portion, and when viewed from the bonding direction between the vibrating device and the cover, the vibrating device The portion of the vibration portion other than the connection portion with the first frame portion is separated from the first frame portion by a slit that penetrates the vibration device along the bonding direction, and the cover body has a second frame portion that surrounds the second cavity and includes a second bonding surface that is bonded to the first bonding surface by the adhesive, the first cavity and the second cavity are connected by the slit, a convex portion that protrudes toward the second bonding surface is formed on the first bonding surface, and a step difference that is recessed toward the side opposite to the vibration device is formed on the inner surface of the second bonding surface that faces the second cavity.

[0011] Another example of a transducer of one side of the present disclosure comprises: a supporting substrate having a first cavity; a vibrating device supported by the supporting substrate; and a cover having a second cavity and bonded to the vibrating device by an adhesive; and the vibrating device comprises: a first frame portion, which surrounds the first cavity when viewed from the cover, and has a first bonding surface bonded to the cover by the adhesive; and a vibrating portion, which faces the first cavity and has a piezoelectric element; and a portion of the vibrating portion is connected to the first frame portion, and a portion of the vibrating portion is bonded to the vibrating device from the bonding direction of the cover. When observed in the direction, the portion of the vibration portion other than the connection portion with the first frame portion is separated from the first frame portion by a slit that passes through the vibration device along the bonding direction, and the cover body has a second frame portion, which surrounds the second cavity and includes a second bonding surface that is bonded to the first bonding surface by the adhesive, the first cavity and the second cavity are connected through the slit, and a convex portion that protrudes toward the second bonding surface is formed on the first bonding surface, and when observed from the bonding direction, the size of the second cavity is larger than the size of the first cavity.

[0012] In a method for manufacturing a transducer according to another aspect of the present disclosure, the transducer comprises: a supporting substrate having a first cavity; a vibrating device stacked on the supporting substrate; and a cover having a second cavity and bonded to the vibrating device by an adhesive; and the method for manufacturing the transducer comprises: a laminate manufacturing step of forming a laminate of a first substrate to be the supporting substrate and the vibrating device; a cover manufacturing step of manufacturing the cover; a bonding step of bonding the cover to the vibrating device; and a cavity forming step of forming the first cavity in a first cavity forming area of ​​the first substrate; and the laminate manufacturing step comprises the following steps: forming an intermediate laminate having: a vibration film forming layer stacked on the first substrate; a piezoelectric element arranged above the first cavity forming area in the vibration film forming layer; and an insulating film covering the piezoelectric element and the vibration film forming layer; in the intermediate laminate, in the outer periphery except for the first cavity forming area A groove is formed along the outer periphery from the insulating film side in an area other than a part; a convex portion is formed in the insulating film outside the predetermined area for forming the first cavity; and a through hole is formed through the intermediate laminate body in a part of the bottom surface of the groove, so that the intermediate laminate body is separated into a vibration part including the piezoelectric element and a frame part that is connected to the vibration part and surrounds the vibration part, thereby obtaining the vibration device; and the cover body manufacturing step includes the following steps: a second cavity that is to be connected to the first cavity through the groove and the through hole is formed on the second substrate that is to become the cover body, thereby obtaining the cover body; in the bonding step, the cover body is attached to the surface of the vibrating device where the convex portion is formed in the state where the bonding surface with the vibrating device is coated with an adhesive, thereby bonding the cover body to the vibrating device; in the cavity forming step, a supporting substrate formed with the first cavity is obtained by forming the first cavity on the first substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a top view of the acoustic wave generating device according to the first embodiment.

[0014] Figure 2 It is a bottom view of the acoustic wave generating device according to the first embodiment.

[0015] Figure 3A It is along Figure 1 A cross-sectional view of the acoustic wave generating device taken along line IIIa-IIIa in FIG.

[0016] Figure 3B It is along Figure 1 A cross-sectional view of the acoustic wave generating device taken along line IIIb-IIIb in FIG.

[0017] Figure 4 It is along Figure 1 A cross-sectional view of the acoustic wave generating device taken along line VI-VI in FIG.

[0018] Figure 5 This is an exploded cross-sectional view of the acoustic wave generating device according to the first embodiment.

[0019] Figure 6 yes Figure 1 A top view of a substrate assembly in an acoustic wave generating device is shown.

[0020] Figure 7 It is along Figure 6 A cross-sectional view taken along line VII-VII.

[0021] Figure 8 yes Figure 3A An enlarged view of area A is shown.

[0022] Fig. 9 Observed from the vibration device side Figure 1 FIG. 2 is a diagram showing a cover body of the sound wave generating device shown.

[0023] Fig.10 This is a cross-sectional view showing one step of a manufacturing process of a substrate assembly semi-finished product (laminated body) in an example of a method for manufacturing the acoustic wave generating device according to the first embodiment.

[0024] Fig.11 It means to continue Fig.10 Cross-sectional view of steps performed subsequent to the step shown.

[0025] Fig.12 It means to continue Fig.11 Cross-sectional view of steps performed subsequent to the step shown.

[0026] Fig.13 It means to continue Fig.12 Cross-sectional view of steps performed subsequent to the step shown.

[0027] Fig.14A It means to continue Fig.13 A top view of a step performed subsequent to the step shown.

[0028] Fig. 14B It is along Fig.14A Cross-sectional view along line XIVb-XIVb in FIG.

[0029] Fig.15A It means to continue Fig.14A and Fig. 14B A top view of a step performed subsequent to the step shown.

[0030] Fig. 15B It is along Fig.15ACross-sectional view along line XVb-XVb in FIG.

[0031] Fig.16 This is a cross-sectional view showing one step of a manufacturing process of a lid body in one example of a method for manufacturing the acoustic wave generating device according to the first embodiment.

[0032] Fig.17A It means to continue Fig.16 A top view of a step performed subsequent to the step shown.

[0033] Fig. 17B It is along Fig.17A Cross-sectional view along line XVIIb-XVIIb.

[0034] Fig.18A It means to continue Fig.17A and Fig. 17B A top view of a step performed subsequent to the step shown.

[0035] Fig.18B It is along Fig.18A XVIIIb-XVIIIb cross-sectional view.

[0036] Fig.19 It means to continue Fig.18A and Fig.18B Cross-sectional view of steps performed subsequent to the step shown.

[0037] Fig. 20 It means to continue Fig.19 Cross-sectional view of steps performed subsequent to the step shown.

[0038] Fig.21 It means to continue Fig. 20 Cross-sectional view of steps performed subsequent to the step shown.

[0039] Fig. 22 By implementing Fig.21 A cross-sectional view of a cover body obtained by a step following the step shown.

[0040] Fig.23 The drawings show a step of joining a substrate assembly semi-finished product (laminated body) and a lid body manufactured in an example of the method for manufacturing the acoustic wave generating device according to the first embodiment.

[0041] Fig.24 It is a drawing for explaining a reference example of a method of forming a hole portion in a silicon layer.

[0042] Fig.25 It is a diagram for explaining a method of forming a hole portion in a silicon substrate when a silicon oxide film exists on a silicon layer.

[0043] Fig.26 It is a top view of the acoustic wave generating device according to the second embodiment.

[0044] Fig. 27 It is along Fig.26 A cross-sectional view of the acoustic wave generating device taken along line XXVI-XXVI is shown.

[0045] Fig.28 Observed from the vibration device side Fig.26 FIG. 2 is a diagram showing a cover body of the sound wave generating device shown.

[0046] Fig.29 This is a cross-sectional view showing one step of the manufacturing process of the cover body included in the acoustic wave generating device of the second embodiment.

[0047] Fig.30 It means to continue Fig.29 Cross-sectional view of steps performed subsequent to the step shown.

[0048] Fig.31 It means to continue Fig.30 Cross-sectional view of steps performed subsequent to the step shown.

[0049] Fig.32 It is a top view of the acoustic wave generating device according to the third embodiment.

[0050] Fig.33 It is along Fig.32 A cross-sectional view of the acoustic wave generating device along line XXXIII-XXXIII in FIG.

[0051] Fig.34 It is a top view of the acoustic wave generating device according to the fourth embodiment.

[0052] Fig.35 It is along Fig.34 A cross-sectional view of the acoustic wave generating device taken along line XXXV-XXXV in FIG.

[0053] Fig.36 It is a top view of the sound wave generating device of variation example 1.

[0054] Fig.37 It is along Fig.36 A cross-sectional view of the acoustic wave generating device 1 taken along line XXXVII-XXXVII in FIG.

[0055] Fig.38 It is along Fig.36 A cross-sectional view of the acoustic wave generating device 1 taken along line XXXIII-XXXIII in FIG.

[0056] Fig.39 It is a figure used to illustrate the modification example 2. DETAILED DESCRIPTION

[0057] [Details]

[0058] Hereinafter, the embodiments will be described with reference to the drawings. In the description, the same reference numerals are given to elements having the same elements or the same functions, and repeated descriptions are omitted.

[0059] (First embodiment)

[0060] Figure 1 It is a top view of the acoustic wave generating device (transducer) according to the first embodiment. Figure 2 It is a bottom view of the acoustic wave generating device according to the first embodiment. Figure 3A It is along Figure 1 A cross-sectional view of the acoustic wave generating device taken along line IIIa-IIIa in FIG. Figure 3B It is along Figure 1 A cross-sectional view of the acoustic wave generating device taken along line IIIb-IIIb in FIG. Figure 4 It is along Figure 1 A cross-sectional view of the acoustic wave generating device taken along line VI-VI in FIG. Figure 5 This is an exploded cross-sectional view of the acoustic wave generating device according to the first embodiment. Figure 5 Indicated in Figure 3A The acoustic wave generating device is shown in a state where the cover body and the substrate assembly are separated. Figure 6 yes Figure 1 A top view of a substrate assembly in an acoustic wave generating device is shown. Figure 7 It is along Figure 6 A cross-sectional view taken along line VII-VII.

[0061] The sound wave generating device 1 is a device that generates sound waves by vibrating the air through the vibration of a piezoelectric film. Since the sound wave generating device 1 utilizes the vibration of a piezoelectric film, it can also be called a piezoelectric film device. The sound wave generating device 1 can be, for example, a speaker, or an ultrasonic generating device that generates ultrasonic waves. In this case, both the speaker and the ultrasonic generating device vibrate the air and can operate with roughly the same structure, but the frequency domains used are different, namely the audible range and the ultrasonic range. The sound wave generating device 1 is, for example, a MEMS (Micro Electro Mechanical Systems) device that utilizes piezoelectric characteristics. The following describes the sound wave generating device 1 in the form of a speaker.

[0062] like Figure 1 , Figure 2 , Figure 3A , Figure 3B , Figure 4 and Figure 5 As shown, the acoustic wave generating device 1 includes a substrate assembly 2 and a cover 3. The cover 3 is bonded to the substrate assembly 2 by an adhesive 100. The substrate assembly 2 includes a supporting substrate 4 and a vibrating device 6 provided on the supporting substrate 4.

[0063] The support substrate 4 is a quadrilateral (roughly rectangular) when viewed from above. In the following, the long side direction of the roughly rectangular support substrate 4 when viewed from above is set as the X direction, the short side direction is set as the Y direction, and the direction intersecting the X direction and the Y direction (that is, the thickness direction of the support substrate 4) is set as the Z direction for description. The Z direction is also the bonding direction of the vibrator 6 and the cover body 3 of the substrate assembly 2. In the Z direction, the direction in which the vibrator 6 is located relative to the support substrate 4 is set as "up", and the direction in which the support substrate 4 is located relative to the piezoelectric element 10 is set as "down" for description.

[0064] The supporting substrate 4 includes a silicon (Si) substrate 32 and an oxide film 33 formed on the surface of the silicon substrate 32. The thickness of the supporting substrate 4 is about 380 μm.

[0065] The support substrate 4 has a cavity (first cavity) 5 formed by a through hole penetrating in the Z direction. The cavity 5 is a rectangular parallelepiped having a quadrilateral opening 5a on the lower surface (bottom surface) side of the cavity 5 as a bottom surface in a plan view.

[0066] The support substrate 4 is frame-shaped in a plan view. The support substrate 4 includes a first portion 41, a second portion 42, a third portion 43, and a fourth portion 44. The first portion 41 and the third portion 43 extend in the Y direction with the cavity 5 interposed therebetween in the X direction. The second portion 42 and the fourth portion 44 extend in the X direction with the cavity 5 interposed therebetween in the Y direction. That is, the first portion 41, the second portion 42, the third portion 43, and the fourth portion 44 surround the cavity 5.

[0067] The inner surface 411 of the first portion 41, the inner surface 421 of the second portion 42, the inner surface 431 of the third portion 43, and the inner surface 441 of the fourth portion 44 are also side surfaces of the cavity 5. Unless otherwise specified, the inner surfaces 411, 421, 431, and 441 are flat surfaces.

[0068] like Figure 3A , Figure 3B , Figure 4 , Figure 5 and Figure 6 As shown, the vibration device 6 includes: a first frame portion 61 that surrounds the cavity 5 when viewed from the cover body 3; and a cantilever (vibration portion) 62 that faces the cavity 5 when viewed from above. A portion of the cantilever 62 is connected to the first frame portion 61. The portion of the cantilever 62 other than the connection portion with the first frame portion 61 is separated from the first frame portion 61 by a slit 9 that penetrates the vibration device 6 in the Z direction.

[0069] The plan view shape of the first frame portion 61 is the same as that of the supporting substrate 4 . That is, the plan view shape of the first frame portion 61 is a substantially rectangular plan view shape. The first frame portion 61 includes a first portion 611 , a second portion 612 , a third portion 613 , and a fourth portion 614 .

[0070] The first portion 611 is supported by the first portion 41 of the support substrate 4. The first portion 611 is along the Y direction on the first portion 41.

[0071] The second portion 612 is supported by the second portion 42 of the support substrate 4. The second portion 612 is along the X direction on the second portion 42.

[0072] The third portion 613 is supported by the third portion 43 of the support substrate 4. The third portion 613 is along the Y direction on the third portion 43.

[0073] The fourth portion 614 is supported by the fourth portion 44 of the supporting substrate 4. The fourth portion 614 is along the X direction on the fourth portion 44.

[0074] The first frame portion 61 is a portion of the vibrating device 6 that is bonded to the cover 3. The surface of the first frame portion 61 is a bonding surface (first bonding surface) 61a with the cover 3. Figure 6 As shown, on the bonding surface 61 a , a plurality of protrusions 8 are discretely arranged so as to surround the cavity 5 in a plan view.

[0075] exist Figure 6 In the illustrated embodiment, when viewed from the Z direction, the plurality of protrusions 8 arranged in a ring shape so as to surround the cavity 5 surround the cavity 5 in two layers. Specifically, two protrusion rows are arranged in the first portion 41 and the third portion 43 at intervals along the X direction, and the two protrusion rows are composed of a plurality of protrusions 8 arranged discretely along the Y direction. In the second portion 42 and the fourth portion 44, two protrusion rows are arranged in the Y direction at intervals, and the two protrusion rows are composed of a plurality of protrusions 8 arranged discretely along the X direction.

[0076] In the present disclosure, the bonding surface 61a means the surface of the first frame portion 61 when the protrusion 8 is not formed. That is, the plane including the bottom surface of the protrusion 8 is the bonding surface 61a.

[0077] The plurality of protrusions 8 function as spacers between the vibration device 6 and the cover 3. Figure 3A , Figure 3B and Figure 4 As shown, the vibration device 6 and the cover 3 are bonded together by an adhesive 100 disposed in the gap formed by the plurality of protrusions 8 .

[0078] The number and arrangement of the convex portions 8 are not limited to the illustrated forms. The plurality of convex portions 8 may not surround the cavity 5 in two layers, for example, may surround the cavity 5 in a single layer, or may surround the cavity 5 in three or more layers. The convex portions 8 respectively arranged in the first portion 611, the second portion 612, the third portion 613, and the fourth portion 614 may also extend along the respective extending directions of the first portion 611, the second portion 612, the third portion 613, and the fourth portion 614.

[0079] The cantilever 62 has a piezoelectric element 10. The cantilever 62 is configured to be vibrated in the Z direction by the piezoelectric element 10. A portion of the cantilever 62 is connected to the first frame portion 61. When viewed from the Z direction, the portion of the cantilever 62 other than the portion connected to the first frame portion 61 is separated from the first frame portion 61 by the slit 9 that penetrates the vibration device 6 in the Z direction. In the following description, unless otherwise specified, the description is of the form in which the cantilever 62 is connected to the first portion 611 of the first frame portion 61.

[0080] The cantilever 62 is a rectangular shape in a plan view that is substantially similar to the cavity 5. The cantilever 62 has a first edge 621, a second edge 622, a third edge 623, and a fourth edge 624. The first edge 621, the second edge 622, the third edge 623, and the fourth edge 624 constitute the outer periphery of the cantilever 62 in a plan view.

[0081] The first edge 621 is along the Y direction. The first edge 621 is a connection portion with the first portion 611 included in the first frame portion 61 .

[0082] The second edge 622 is along the X direction. The second edge 622 faces the second portion 612 of the first frame portion 61 in a plan view. The second edge 622 is separated from the second portion 612 by the slit 9. The portion of the slit 9 separating the second edge 622 from the second portion 612 is referred to as a first portion 9a.

[0083] The third edge 623 extends along the Y direction. The third edge 623 faces the third portion 613 of the first frame portion 61 in a plan view. The portion of the slit 9 separating the third edge 623 and the third portion 613 is referred to as a second portion 9b.

[0084] The fourth edge 624 is along the X direction. The fourth edge 624 faces the fourth portion 614 of the first frame portion 61 in a plan view. The portion of the slit 9 that separates the third edge 623 from the third portion 613 is referred to as a third portion 9c.

[0085] use Figure 3A , Figure 3B , Figure 4 and Figure 5 , describing the layer structure of the vibration device 6.

[0086] The vibration device 6 has a vibration film forming layer 7. The vibration film forming layer 7 is formed on the supporting substrate 4. The vibration film forming layer 7 is a laminated film in which a silicon layer (active layer including silicon) 34 and a silicon oxide film (silicon oxide layer) 35 are laminated in this order from the supporting substrate 4 side. The film thickness of the silicon layer 34 is, for example, 20 μm. The film thickness of the silicon oxide film 35 is, for example, 1.5 μm.

[0087] In the first embodiment, a first hydrogen barrier film 14A is formed on the vibration film forming layer 7. The first hydrogen barrier film 14A includes, for example, an aluminum oxide (Al2O3) film. An example of the thickness of the first hydrogen barrier film 14A is greater than or equal to 20 nm and less than or equal to 100 nm. The portion of the vibration film forming layer 7 included in the cantilever 62 is referred to as a vibration film 7a.

[0088] The piezoelectric element 10 is disposed on the portion of the first hydrogen barrier film 14A within the cantilever 62. The piezoelectric element 10 includes a lower electrode 11 formed on the first hydrogen barrier film 14A, a piezoelectric film 12 formed on the lower electrode 11, and an upper electrode 13 formed on the piezoelectric film 12.

[0089] The lower electrode 11 and the upper electrode 13 are formed of a conductive metal thin film such as platinum, molybdenum, iridium, titanium, etc. The thickness of the lower electrode 11 is, for example, 200 nm, and the thickness of the upper electrode 13 is, for example, 80 nm.

[0090] The piezoelectric film 12 includes, for example, lead zirconate titanate (PZT). The piezoelectric film 12 may also include a niobium-doped lead zirconate titanate (PNZT) film, a lanthanum-doped lead zirconate titanate (PLZT) film, a strontium barium titanate (BST) film, a strontium bismuth tantalate (SBT) film, a strontium barium niobate (SBN) film, a lithium niobate (LiNbO3) film, a barium titanate (TiBaO3) film, a lanthanum strontium copper oxide (LSCO) film, a potassium dihydrogen phosphate (KDP) film, a potassium tantalum niobate (KTN) film, a magnesium niobate lead titanate (PMN-PT) ceramic film, a zinc niobate lead titanate (PZN-PT) ceramic film, aluminum nitride (AIN), zinc oxide (ZnO), lead titanate (PbTiO3), etc. The film thickness of the piezoelectric film 12 is, for example, 2 μm.

[0091] A second hydrogen barrier film 14B is formed on the first hydrogen barrier film 14A. A portion of the piezoelectric element 10 is formed on the first hydrogen barrier film 14A, and the piezoelectric element 10 is covered by the second hydrogen barrier film 14B. The second hydrogen barrier film 14B includes, for example, an aluminum oxide film. An example of the thickness of the second hydrogen barrier film 14B is greater than or equal to 20 nm and less than or equal to 100 nm. The second hydrogen barrier film 14B is provided to prevent the characteristics of the piezoelectric film 12 from being degraded due to hydrogen reduction.

[0092] An interlayer insulating film 15 is stacked on the second hydrogen barrier film 14B. The interlayer insulating film 15 is composed of, for example, a film (TEOS film) containing tetraethoxysilane (TEOS). The interlayer insulating film 15 may also contain silicon nitride (SiN) or the like. An example of the thickness of the interlayer insulating film 15 is 0.2 μm or more and 1.5 μm or less.

[0093] Hereinafter, the second hydrogen barrier film 14B and the interlayer insulating film 15 may be collectively referred to as an insulating film 20 .

[0094] like Figure 6 As shown, an upper wiring 17 and a lower wiring 18 are formed on the interlayer insulating film 15. The lower wiring 18 and the upper wiring 17 are formed of, for example, a metal material containing Al (aluminum). The thickness of the lower wiring 18 and the upper wiring 17 is, for example, 1 μm.

[0095] The upper wiring 17 includes an upper pad portion 17a, a first wiring portion 17b, and a second wiring portion 17c. The upper pad portion 17a is arranged near a corner formed by the first portion 611 and the second portion 612 of the first frame portion 61 in a plan view. The upper pad portion 17a is formed wider than the first wiring portion 17b and the second wiring portion 17c. The first wiring portion 17b is arranged at an end portion of the interlayer insulating film 15 on the side of the first edge portion 621 of the cantilever 62. The first wiring portion 17b extends in the Y direction. The second wiring portion 17c is a portion of the upper wiring 17 that connects the upper pad portion 17a and the first wiring portion 17b.

[0096] A contact hole 19a is formed between the first wiring portion 17b and the upper electrode 13 and continuously penetrates the second hydrogen barrier film 14B and the interlayer insulating film 15 (see Figure 3A , Figure 3B and Figure 5 ). A portion of the first wiring portion 17b enters the contact hole 19a and is connected to the upper electrode 13 in the contact hole 19a. A plurality of contact holes 19a may be formed discretely along the Y direction.

[0097] The lower wiring 18 includes a lower pad portion 18a, a first wiring portion 18b, and a second wiring portion 18c. The lower pad portion 18a is arranged near a corner formed by the first portion 611 and the fourth portion 614 of the first frame portion 61 in a plan view. The lower pad portion 18a is formed wider than the first wiring portion 18b and the second wiring portion 18c. The first wiring portion 18b is arranged at an end portion (rear end portion) on the side of the connection portion between the cantilever 62 and the first frame portion 61 in the interlayer insulating film 15. The first wiring portion 18b extends in the Y direction. The first wiring portion 18b is spaced apart from the first wiring portion 17b in the X direction. The second wiring portion 18c is a portion of the lower wiring 18 that connects the lower pad portion 18a and the first wiring portion 18b.

[0098] A contact hole 19b ( 19b ) is formed between the first wiring portion 18b and the lower electrode 11 and continuously penetrates the second hydrogen barrier film 14B and the interlayer insulating film 15. Figure 3A , Figure 3B and Figure 5 A part of the first wiring portion 18b enters the contact hole 19b and is connected to the lower electrode 11 in the contact hole 19b. A plurality of contact holes 19b may be formed discretely along the Y direction.

[0099] On the interlayer insulating film 15, cores 8a included in the protrusions 8 are formed at positions corresponding to the plurality of protrusions 8. The cores 8a are similar in shape to the protrusions 8 and are smaller than the protrusions 8. The cores 8a are formed of a metal material including aluminum (Al). The thickness of the cores 8a is, for example, 1 μm.

[0100] A passivation film 16 is formed on the interlayer insulating film 15 so as to cover the upper wiring 17, the lower wiring 18, and the plurality of core portions 8a. The passivation film 16 is composed of, for example, a film (TEOS film) containing tetraethoxysilane (TEOS). The passivation film 16 may also contain silicon nitride (SiN) or the like. An example of the thickness of the passivation film 16 is 0.1 μm or more and 1.0 μm or less.

[0101] The passivation film 16 is formed with an upper pad opening 16a that exposes a portion of the upper pad portion 17a and a lower pad opening 16b that exposes a portion of the lower pad portion 18a (see FIG. 1 ). Figure 1 ).

[0102] The plurality of protrusions 8 are formed by covering the plurality of core portions 8 a with the passivation film 16 .

[0103] In the vibration device 6 having the above-described layer structure, the slit (gap) 9 is formed so as to communicate with the cavity 5 by continuously penetrating from the passivation film 16 to the silicon layer 34 .

[0104] The inner surface 615 of the first frame portion 61 facing the slit 9 is formed with a groove extending from the joint surface 61a toward the side opposite to the cover body 3 ( Figure 3A , Figure 3B , Figure 4 and Figure 5 Specifically, Figure 3A and Figure 3B As shown in FIG. 1 , a step S1 is formed on the inner surface 613a of the third portion 613 of the first frame portion 61. Figure 4As shown, a step S1 is formed on the inner surface 612a of the second portion 612 of the first frame portion 61, and a step S1 is formed on the inner surface 614a of the fourth portion 614 of the first frame portion 61. The inner surface 612a faces the first portion 9a of the slit 9 and constitutes a part of the inner surface 615. The inner surface 613a faces the second portion 9b of the slit 9 and constitutes a part of the inner surface 615. The inner surface 614a faces the third portion 9c of the slit 9 and constitutes a part of the inner surface 615.

[0105] On the inner surface 611a (see Figure 6 ), and the regions on both sides of the connection portion with the cantilever 62 in a plan view also have a step difference S1. The region where the step difference S1 is formed in the inner surface 611a of the first portion 611 is the region facing the first portion 9a and the third portion 9c of the slit 9, and constitutes a part of the inner surface 615.

[0106] A step (second step) S2 is formed at a portion of the outer peripheral edge of the cantilever 62 that faces the slit 9 . Specifically, the step S2 is formed at the second edge 622 , the third edge 623 , and the fourth edge 624 .

[0107] The second edge 622 is an edge facing the first portion 9 a of the slit 9 .

[0108] The third edge 623 is an edge facing the second portion 9 b of the slit 9 .

[0109] The fourth edge 624 is an edge facing the third portion 9 c of the slit 9 .

[0110] In the first frame portion 61, a step S1 is formed on the inner surface 615 facing the slit 9, and a step S2 is formed on the portion of the outer periphery of the cantilever 62 facing the slit 9. Therefore, in the first embodiment, the slit 9 has an upper slit portion 91 and a lower slit portion 92 in sequence from the passivation film 16 toward the silicon substrate 32. The width of the lower slit portion 92 is narrower than the width of the upper slit portion 91. An example of the length of the width of the lower slit portion 92 is greater than 1 μm and less than 10 μm. The width of the lower slit portion 92 is a portion that contributes to the sound characteristics of the sound wave generating device 1.

[0111] use Figure 8 , an example of the step difference S1 and the step difference S2 is specifically described. Figure 8 yes Figure 3A The step S1 formed on the inner surfaces 611a, 612a, 613a, and 614a has the same structure. The step S2 formed on the second edge 622, the third edge 623, and the fourth edge 624 has the same structure. Figure 8The step S1 formed on the inner surface 613a (inner surface 615) and the step S2 formed on the third edge 623 are described, and the description of the step S1 formed on the inner surfaces 611a, 612a, 614a and the step S2 formed on the second edge 622 and the fourth edge 624 is omitted.

[0112] like Figure 8 As shown, the step S1 is formed by retreating a predetermined area of ​​the inner surface 613a on the bonding surface 61a side toward the side opposite to the slit 9. Therefore, compared with the case where the step S1 is not formed, the corner formed by the inner surface 613a and the bonding surface 61a also retreats toward the side opposite to the slit 9. The retreat amount d1 is, for example, not less than 1 μm and not more than 5 μm. Figure 8 In the illustrated embodiment, the inner surface 613a is recessed in a region from the bonding surface 61a to the passivation film 16 formed on the silicon oxide film 35. In the first embodiment, the step S1 portion is covered with the passivation film 16.

[0113] The step S2 is formed by retreating a predetermined region on the interlayer insulating film 15 side of the third edge portion 623 toward the side opposite to the slit 9. The retreat amount d2 is, for example, not less than 1 μm and not more than 5 μm. Figure 8 In the illustrated embodiment, the third edge portion 623 is retracted in a region from the surface of the interlayer insulating film 15 to the silicon oxide film 35 in the third edge portion 623 .

[0114] Next, use Figure 1 , Figure 3A , Figure 3B , Figure 4 , Figure 5 , Figure 8 and Fig. 9 The cover body 3 will be described. Fig. 9 1 is a diagram showing the cover 3 viewed from the substrate assembly 2 side. The cover 3 includes a silicon substrate. The cover 3 is disposed on the substrate assembly 2 so as to cover the vibration device 6. The cover 3 is bonded to the first frame portion 61 using an adhesive 100.

[0115] The cover body 3 has a cavity (second cavity) 3a formed by a through hole penetrating in the Z direction. When viewed from the Z direction, the cover body 3 is frame-shaped. That is, the cover body 3 has a second frame portion 30. The second frame portion 30 includes a first portion 301, a second portion 302, a third portion 303, and a fourth portion 304. The first portion 301 and the third portion 303 extend in the Y direction with the cavity 3a therebetween in the X direction. The second portion 302 and the fourth portion 304 extend in the X direction with the cavity 3a therebetween in the Y direction. That is, the first portion 301, the second portion 302, the third portion 303, and the fourth portion 304 surround the cavity 3a.

[0116] The lid body 3 is configured such that the upper and lower pads 17a and 18a are opened above when the lid body 3 is bonded to the substrate assembly 2 so that wiring can be connected to the upper and lower pads 17a and 18a.

[0117] Specifically, the first portion 301 is disposed between the upper pad portion 17a and the lower pad portion 18a in a plan view. The ends of the second portion 302 and the fourth portion 304 on the first portion 301 side are located closer to the third portion 303 side than the upper pad portion 17a and the lower pad portion 18a. In other words, in a plan view, the cover body 3 has a shape in which two corners are removed, and the two corners are formed when the first portion 301 is extended toward both sides of the first portion 301 in the X direction, and the second portion 302 and the fourth portion 304 are extended toward the first portion 301 side along the X direction.

[0118] Hereinafter, for convenience of description, the portion of the cover 3 that opens the upper portion of the upper pad portion 17a is referred to as an opening portion 305a, and the portion that opens the upper portion of the lower pad portion 18a is referred to as an opening portion 305b.

[0119] In the cover body 3, a plurality of recessed portions 306a are formed on the bonding surface (second bonding surface) 306 that is bonded to the first frame portion 61. Fig. 9 As shown, the plurality of recessed portions 306 a are arranged so as to be adjacent to the raised portion 8 when viewed from the Z direction. Fig. 9 The convex portion 8 is shown by a two-dot chain line in the figure to show the arrangement relationship between the concave portion 306a and the convex portion 8. A part of the concave portion 306a may overlap with the convex portion 8. Fig. 9 In the embodiment shown, in the first portion 301 of the cover body 3, a plurality of recessed portion rows are arranged along the extending direction ( Fig. 9 Y direction), and are arranged side by side in a direction orthogonal to the extending direction of the first portion 301 ( Fig. 9 The concave portion row along the extending direction of the first portion 301 is a row formed by a plurality of concave portions 306a arranged discretely along the extending direction of the first portion 301. Fig. 9 In the embodiment shown in FIG. 1 , a plurality of recesses 306a are arranged in the second portion 302, the third portion 303, and the fourth portion 304 as in the case of the first portion 301. The top view shape (shape when viewed from the Z direction) of the recess 306a is Fig. 9 The example shown is a square, but it can also be a rectangle, other polygons, a circle, etc.

[0120] like Fig. 9In the embodiment shown, the concave portion 306a of the concave portion row closest to the cavity 3a in the second portion 302, the third portion 303 and the fourth portion 304 can be connected to form a linear concave portion 306b. The embodiment in which the concave portion 306b is further formed will be described below. The concave portion 306b can also be formed in the first portion 301.

[0121] The recessed portions 306a and 306b are portions for releasing the adhesive 100 used to join the cover body 3 and the first frame portion 61 when the cover body 3 and the first frame portion 61 are joined as described below. Since the adhesive 100 enters between the recessed portions 306a and 306b, it is sufficient to form the recessed portions 306a and 306b with a volume that prevents the adhesive 100 from overflowing to the slit 9 side.

[0122] Next, an example of a method for manufacturing the acoustic wave generating device 1 of the first embodiment is described. The method for manufacturing the acoustic wave generating device 1 includes: a step of manufacturing a substrate assembly semi-finished product (laminated body) 2A (substrate assembly semi-finished product manufacturing step), a step of manufacturing a cover body 3 (cover body manufacturing step), a step of joining the substrate assembly semi-finished product 2A and the cover body 3 (joining step), and a step of forming a mold cavity 5 in the substrate assembly semi-finished product 2A (mold cavity forming step). In the mold cavity forming step (cavity forming step), the substrate assembly semi-finished product 2A is a part for obtaining the substrate assembly 2.

[0123] <Substrate assembly semi-finished product manufacturing steps>

[0124] First, the substrate assembly semi-finished product manufacturing step (laminated body manufacturing step) will be described.

[0125] Initially, if Fig.10 As shown in FIG. 1 , a SOI (Silicon On Insulator) substrate is subjected to thermal oxidation treatment (thermal oxidation treatment step). The SOI substrate includes a silicon substrate 32 as a support layer, an oxide film 33 as a BOX layer formed on the surface of the silicon substrate 32, and a silicon layer 34 as an active layer formed on the surface of the oxide film 33. By thermal oxidation treatment, a silicon oxide film 35 is formed on the surface of the silicon layer 34 opposite to the oxide film 33, and a silicon oxide film 31 is formed on the surface of the silicon substrate 32 opposite to the oxide film 33.

[0126] Fig.10 The silicon oxide film 35, silicon substrate 32 and oxide film 33 shown are portions that will become the support substrate 4 by performing a predetermined process in a subsequent step, and the silicon layer 34 and silicon oxide film 35 are portions that constitute the vibration film forming layer 7. Therefore, when the stacked structure of the silicon oxide film 31, silicon substrate 32 and oxide film 33 is referred to as a substrate (first substrate) 401, the silicon oxide film 31, silicon substrate 32 and oxide film 33 are thermally oxidized to form a support substrate 401. Fig.10The SOI substrate having the layer structure shown has a structure in which a vibration film forming layer 7 is stacked on a substrate 401 .

[0127] Next, if Fig.11 As shown in FIG. 1 , the first hydrogen barrier film 14A is formed on the silicon oxide film 35 of the vibration film forming layer 7 (first hydrogen barrier film forming step). Thereafter, the piezoelectric element 10 is formed on the first hydrogen barrier film 14A (piezoelectric element forming step). The piezoelectric element 10 is formed above the cavity forming area (first cavity forming area) 501 of the substrate 401 to be the supporting substrate 4.

[0128] The piezoelectric element 10 is formed, for example, in the following manner. A lower electrode film as a material film of the lower electrode 11, a piezoelectric material film as a material film of the piezoelectric film 12, and an upper electrode film as a material film of the upper electrode 13 are sequentially formed on the first hydrogen barrier film 14A. Next, the upper electrode film, the piezoelectric material film, and the lower electrode film are patterned, for example, in sequence by photolithography and etching, thereby forming the upper electrode 13, the piezoelectric film 12, and the lower electrode 11. In the case where the upper electrode 13, the piezoelectric film 12, and the lower electrode 11 are obtained from the upper electrode film, the piezoelectric material film, and the lower electrode film, the upper electrode film, the piezoelectric material film, and the lower electrode film are processed in such a manner that the upper electrode 13, the piezoelectric film 12, and the lower electrode 11 are located above the predetermined region 501 for cavity formation. Thus, the piezoelectric film 12 and the electrodes (the lower electrode 11 and the upper electrode 13 ) are formed in the region above the cavity formation planned region 501 in the first hydrogen barrier film 14A, thereby forming the piezoelectric element 10 .

[0129] Next, if Fig.12 As shown in FIG. 1 , a second hydrogen barrier film 14B is formed on the silicon oxide film 35 to cover the exposed surface of the silicon oxide film 35 and the exposed surface of the piezoelectric element 10. The second hydrogen barrier film 14B is, for example, an aluminum oxide film. Thereafter, an interlayer insulating film 15 is formed on the entire surface of the second hydrogen barrier film 14B. As described above, the second hydrogen barrier film 14B and the interlayer insulating film 15 are sometimes collectively referred to as an insulating film 20. Therefore, the step of forming the second hydrogen barrier film 14B and the interlayer insulating film 15 can be referred to as an insulating film forming step.

[0130] Through the above-mentioned thermal oxidation treatment step, the first hydrogen barrier film forming step, the piezoelectric element forming step and the insulating film forming step, an intermediate laminate 101 is obtained by laminating a vibration film forming layer (silicon layer 34 and silicon oxide film 35), a first hydrogen barrier film 14A, a piezoelectric element 10 and an insulating film 20 (a second hydrogen barrier film 14B and an interlayer insulating film 15) on a substrate 401 which should become a supporting substrate 4 (intermediate laminate manufacturing step).

[0131] By etching the insulating film 20 (the second hydrogen barrier film 14B and the interlayer insulating film 15) after the intermediate laminate manufacturing step, Fig.13 When the contact holes 19a and 19b are formed, the insulating film 20 and the first hydrogen barrier film 14A are etched to form a groove 911 to be the upper slit portion 91 (groove forming step).

[0132] The groove portion 911 is a portion that is to become the upper slit portion 91 as described above. Therefore, the groove portion 911 is formed in the intermediate laminate 101 in the area where the slit is to be formed. Specifically, when viewed from the Z direction, the groove portion 911 is formed along a portion other than a portion of the outer peripheral edge 501a of the area where the cavity is to be formed 501. When viewed from the Z direction, the portion of the outer peripheral edge 501a of the area where the cavity is to be formed 501, where the groove portion 911 is not formed, is a portion corresponding to the connection portion between the first frame portion 61 and the cantilever 62. The groove portion 911 is formed so as to have the outer peripheral edge 501a of the area where the cavity is to be formed 501a on the inner side of the groove portion 911 when viewed from the Z direction. For example, the groove portion 911 is formed so that when viewed from the Z direction, the outer peripheral edge 501a is located at the center of the groove portion 911 in the width direction.

[0133] Then, if Fig.14A and Fig. 14B As shown, a wiring film as a material film of an upper wiring 17 and a lower wiring 18 is formed on the interlayer insulating film 15 including the contact holes 19a and 19b. The wiring film is patterned by photolithography and etching to form the upper wiring 17 and the lower wiring 18, and a plurality of core portions 8a are formed outside the groove portion 911. The plurality of core portions 8a are formed at the configuration positions of the plurality of protrusions 8. As described above, the core portion 8a is formed by the wiring film, so the core portion 8a can also be called a virtual wiring portion.

[0134] Next, the passivation film 16 is formed on the interlayer insulating film 15 so as to cover the upper wiring 17, the lower wiring 18, and the plurality of core portions 8a. The interlayer insulating film 15 and the passivation film 16 are, for example, TEOS films containing tetraethoxysilane (TEOS).

[0135] As described above, the plurality of core portions 8a are also covered with the passivation film 16, thereby obtaining a plurality of convex portions 8. Therefore, the convex portions 8 are formed by the step of forming the core portions 8a and the step of forming the passivation film 16 (convex portion forming step).

[0136] like Fig.15A and Fig. 15B As shown, an upper pad opening 16a exposing a portion of the upper pad portion 17a and a lower pad opening 16b exposing a portion of the lower pad portion 18a are formed in the passivation film 16 by photolithography and etching.

[0137] Furthermore, by photolithography and etching, the passivation film 16 is removed except for the region covering the upper wiring 17 and the lower wiring 18 in the region above the cavity formation planned region 501 in the passivation film 16 to expose the interlayer insulating film 15. This step may be omitted.

[0138] Furthermore, by photolithography and etching, a through hole 912 penetrating the intermediate laminate body 101 is formed in a part of the bottom surface 911a of the groove portion 911. The through hole 912 is formed so as to further penetrate the oxide film 33.

[0139] Specifically, a through hole 912 is formed that penetrates the vibration film forming layer 7 (silicon oxide film 35 and silicon layer 34) and the oxide film 33 from the bottom surface 911a and reaches the silicon substrate 32. The through hole 912 is a portion that should become the lower slit portion 92. Thus, the through hole 912 is formed in such a manner that the width of the through hole 912 is the same as the width of the lower slit portion 92.

[0140] As described above, the through hole 912 is formed, thereby forming the slit 9. By forming the slit 9, the first frame portion 61 and the cantilever 62 are obtained. In other words, the vibration device 6 having the first frame portion 61 and the cantilever 62 is obtained. As a result, the substrate assembly semi-finished product 2A, which is a laminated body in which the vibration device 6 is laminated on the substrate 401, is obtained.

[0141] The through hole 912 is formed in a portion of the bottom surface 911a of the groove portion 911. Therefore, the width of the groove portion 911 is greater than the width of the through hole 912. Thus, the slit 9 obtained by forming the through hole 912 as described above has an upper slit portion 91 and a lower slit portion 92. As described above, the slit 9 is formed using the groove portion 911 and the through hole 912, so the steps S1 and S2 are also formed in the substrate assembly semi-finished product 2A. Since the through hole 912 is formed after the passivation film 16 is formed, the surface of the step S1 includes the passivation film 16.

[0142] <Cover manufacturing steps>

[0143] Next, the lid manufacturing step will be described. The order of the lid manufacturing step and the substrate assembly semi-finished product manufacturing step is not limited.

[0144] like Fig.16As shown, a substrate (second substrate) 70 which is to become a cover body 3 having a cavity 3a is prepared. The substrate 70 has a silicon substrate 71, a first oxide film 72 formed on the surface of the silicon substrate 71, and a second oxide film 73 formed on the back side (the side opposite to the surface) of the silicon substrate 71. The substrate 70 is formed by subjecting the silicon substrate to thermal oxidation treatment. Specifically, the first oxide film 72 and the second oxide film 73 are formed on the surface and the back side by subjecting the silicon substrate to thermal oxidation treatment. In the silicon substrate subjected to the thermal oxidation treatment, the portion between the first oxide film 72 and the second oxide film 73 is the silicon substrate 71.

[0145] like Fig.17A and Fig. 17B As shown, the first oxide film 72 around the island regions 721a, 721b, and 721c is removed by photolithography and etching so that the island regions 721a, 721b, and 721c remain in the first oxide film 72, thereby forming openings 72a, 72b, and 72c.

[0146] Similarly, by photolithography and etching, the first oxide film 72 around the island regions 731a, 721b, and 721c is removed in a manner that the island regions 731a, 731b, and 731c remain in the second oxide film 73, thereby forming openings 72a, 72b, and 72c.

[0147] The outer periphery of the opening 72a and the opening 73b coincides with the outer periphery 308a of the cavity formation planned region 308 in the substrate 70. The outer periphery of the opening 72b and the opening 73b coincides with the open portion 305a (see Figure 1 ) is consistent with the outer periphery of the area to be formed. The outer periphery of the opening 72c and the opening 73c is consistent with the opening 305b (refer to Figure 1 ) are consistent with the outer periphery of the predetermined area to be formed.

[0148] Next, if Fig.18A and Fig.18B As shown, a through hole 73d1 to be the recessed portion 306a and a through hole 73d2 to be the recessed portion 306b are formed in the second oxide film 73 by photolithography and etching.

[0149] Afterwards, if Fig.19 As shown, a support substrate 82 is bonded to the first oxide film 72 with an interlayer separation layer 81. A resist film 83 is formed on the second oxide film 73. At this time, a part of the resist film 83 is also filled in the through hole 73d.

[0150] Then, if Fig. 20As shown, the silicon substrate 71 is etched using the resist film 83 as a mask, thereby forming a through hole 75 that passes through the silicon substrate 71 from the opening 73a to the opening 72a. Similarly, a through hole (not shown) that passes through the substrate 70 from the opening 73b to the opening 72b and a through hole (not shown) that passes through the silicon substrate 71 from the opening 73c to the opening 72c are formed.

[0151] Then, if Fig.21 As shown, after removing the resist film 83, the silicon substrate 71 is etched using the second oxide film 73 as a mask. Thus, the through holes 73d1 and 73d2 are extended toward the silicon substrate 71, forming the recessed portions 306a and 306b.

[0152] Thereafter, the support substrate 82 and the peeling layer 81 are peeled off from the substrate 70. Since the island region 721a is separated from the surroundings by the through hole 75, the region corresponding to the island region 721a in the silicon substrate 71 is removed together with the support substrate 82. Thus, the cavity 3a is formed in the substrate 70. By peeling off the support substrate 82 from the substrate 70, the region corresponding to the island region 721b and the island region 721c in the silicon substrate 71 is removed together with the support substrate 82. Thus, the opening 305a and the opening 305b are formed. Thereafter, by removing the first oxide film 72 and the second oxide film 73, a cavity 3a is obtained. Fig. 22 The cover 3 is shown.

[0153] <Joining steps>

[0154] In the joining step, Fig.23 As shown, adhesive 100 is applied to the surface (joint surface 306) of the cover 3 where the recesses 306a and 306b are formed, except for the recesses 306a and 306b, to fix the cover 3 to the substrate assembly semi-finished product 2A.

[0155] (Mold cavity forming step)

[0156] In the cavity forming step, the silicon oxide film 31 and the silicon substrate 32 of the substrate assembly semi-finished product 2A are ground to thin the silicon substrate 32. Thereafter, a resist mask (not shown) corresponding to the region where the cavity is to be formed is formed on the lower surface of the silicon substrate 32, and the silicon substrate 32 is etched from the lower surface. Thus, the cavity 5 is formed. As a result, the acoustic wave generating device 1 having the supporting substrate 4, the vibrating device 6 and the cover body 3 is obtained (see Figure 1 , Figure 2 , Figure 3A , Figure 3B , Figure 4 and Figure 5 ).

[0157] The cavity forming step may be performed by bonding the support substrate to the cover 3. In this case, after the cavity 5 is formed, the support substrate is peeled off, thereby obtaining the acoustic wave generating device 1.

[0158] The acoustic wave generating device 1 of the first embodiment includes: a supporting substrate 4 having a cavity 5; a vibrating device 6 supported by the supporting substrate; and a cover 3 having a cavity 3a and joined to the vibrating device 6 by an adhesive 100. The vibrating device 6 includes: a first frame portion 61 surrounding the cavity 5 when viewed from the cover 3 and having a joining surface 61a joined to the cover 3 by an adhesive 100; and a cantilever (vibrating portion) 62 facing the cavity 5 and having a piezoelectric element 10. A first edge portion 621 as a part of the cantilever 62 is connected to the first frame portion 61. When viewed from the joining direction (corresponding to the Z direction) of the vibrating device 6 and the cover 3, the portion of the cantilever 62 other than the connecting portion (the first edge portion 621) between the cantilever 62 and the first frame portion 61 is separated from the first frame portion 61 by a slit 9 penetrating the vibrating device 6 in the joining direction. The cover body 3 has a second frame portion 30, which surrounds the cavity 3a and includes a bonding surface 306 bonded to the bonding surface 306 by an adhesive 100. The mold cavity 5 and the cavity 3a are connected through the slit 9. A convex portion 8 protruding toward the bonding surface 306 is formed on the bonding surface 61a. The inner surface 615 of the first frame portion 61 facing the slit 9 is formed with a step S1 recessed from the bonding surface 61a toward the side opposite to the cover body 3.

[0159] As described above, in the sound wave generating device 1, the cantilever 62 disposed opposite to the cavity 5 is connected to the first frame portion 61 at the first edge 621. The second edge 622, the third edge 623 and the fourth edge 624 of the cantilever 62 are separated from the first frame portion 61 by the slit 9. That is, in the cantilever 62, the connection portion between the first edge 621 and the first frame portion 61 is a fixed end, and the end opposite to the fixed end in the X direction is a free end. The cantilever 62 has the piezoelectric element 10, so in the vibration device 6, by applying a driving voltage to the piezoelectric element 10, vibration is generated in the Z direction. This vibration causes the air to vibrate, so that sound waves are generated.

[0160] In the acoustic wave generating device 1, the cover 3 is joined to the substrate assembly 2 including the vibrating device 6. The cover 3 is formed with a cavity 3a which communicates with the cavity 5 via a slit 9. Since the cavity 3a is formed, the vibration of the cantilever 62 is not hindered even if the cover 3 is joined to the substrate assembly 2. Figure 3A As shown, when the cavity 3 a is formed so as to penetrate the cover body 3 , a region corresponding to the cavity 3 a is opened in the surface (upper surface) of the cover body 3 opposite to the bonding surface 306 .

[0161] Thus, in the sound wave generating device 1 including the cover body 3 , the sound generated by the vibration of the cantilever 62 is radiated to the outside through the opening 5 a on the lower surface side of the cavity 5 and the cavity 3 a .

[0162] In the acoustic wave generating device 1, air leakage is prevented by bonding the cover 3 to the substrate assembly 2, thereby improving the acoustic characteristics of the acoustic wave generating device 1. Since the cover 3 is provided, the vibration device 6 is protected. Furthermore, since the cover 3 is provided, the rigidity of the chip is improved.

[0163] The cover 3 is bonded to the substrate assembly 2 (specifically, the vibration device 6) by the adhesive 100. As described in the example of the method for manufacturing the sound wave generating device 1, when the cover 3 is bonded to the substrate assembly 2, the cover 3 is attached to the vibration device 6 in a state where the adhesive 100 is applied to the bonding surface 306 of the cover 3. In this case, for example, the closer the distance between the bonding surface 306 and the bonding surface 61a is, the more adhesive 100 overflows from the bonding portion between the bonding surface 306 and the bonding surface 61a. In the sound wave generating device 1 that generates sound by vibration of the cantilever 62, it is desirable that the width of the slit 9 is small from the viewpoint of preventing sound leakage and the characteristics of the bass range. Therefore, if the amount of adhesive 100 overflowing to the slit 9 side is large, the adhesive 100 and the cantilever 62 may interfere with each other.

[0164] The convex portion 8 is formed on the bonding surface 61a of the vibration device 6 of the first embodiment. The convex portion 8 functions as a spacer that defines the distance between the bonding surface 61a and the bonding surface 306 of the cover body 3, or as a stopper that prevents the bonding surface 306 from approaching the bonding surface 61a beyond a certain distance when the cover body 3 is bonded to the substrate assembly 2. In this case, the distance between the bonding surface 61a and the bonding surface 306 is longer than the distance in the case where the convex portion 8 is not formed. Therefore, more adhesive 100 can be present between the bonding surface 61a and the bonding surface 306, so the amount of adhesive 100 overflowing to the slit 9 side can be reduced.

[0165] Furthermore, in the region facing the slit 9 in the inner surface 615 (specifically, the inner surfaces 611a, 612a, 613a, and 614a) of the first frame portion 61 of the vibrating element 6, a step S1 is formed which is recessed downward (toward the supporting substrate 4) from the bonding surface 61a. At the corner portion between the step S1 and the bonding surface 61a (the inner edge portion of the bonding surface 61a), the surface tension of the adhesive 100 is used to suppress the bonding. Figure 8 The adhesive 100 shown overflows to the slit 9. In other words, the step S1 defines a stop position for the adhesive 100 toward the slit 9. Furthermore, even if a portion of the adhesive 100 flows into the step S1, the adhesive 100 can be stopped at the bottom (or lower portion) of the step S1.

[0166] Therefore, in the sound wave generating device 1 having the vibrating device 6 formed with the convex portion 8 and the step S1, the adhesive 100 is not easy to overflow to the slit 9 side. Therefore, the gap between the first frame portion 61 and the cantilever 62 separated by the slit 9 can be properly ensured. Therefore, the adhesive 100 can be prevented from interfering with the cantilever 62. Since the overflow of the adhesive 100 to the slit 9 side is suppressed, the width of the slit 9 can also be made narrower. As a result, sound leakage can be further prevented, and the improvement of the bass range characteristics is also achieved.

[0167] An example of a method for manufacturing the acoustic wave generating device 1 of the first embodiment includes: a substrate assembly semi-finished product manufacturing step (laminated body manufacturing step) of manufacturing a laminated body of a substrate 401 to be a supporting substrate 4 and a vibrating device 6, that is, a substrate assembly semi-finished product 2A; a cover body manufacturing step of manufacturing a cover body 3; a bonding step of bonding the cover body 3 to the vibrating device 6; and a cavity forming step (cavity forming step) of forming a cavity 5 in a cavity forming area 501 of the substrate 401. The substrate assembly semi-finished product manufacturing step includes the following steps: forming an intermediate laminated body 101 having a vibration film forming layer 7, a piezoelectric element 10, and an insulating film 20, wherein the vibration film forming layer 7 is laminated on the substrate 401, the piezoelectric element 10 is provided above the cavity forming area 501 in the vibration film forming layer 7, and the insulating film 20 covers the piezoelectric element 10 and the vibration film forming layer 7; in the intermediate laminated body 101, a portion of the outer periphery 501a of the cavity forming area 501 is formed with a dielectric film 20; The vibrating device 6 is obtained by forming a groove 911 from the insulating film 20 side along the outer peripheral edge 501a in the region outside the cavity forming area 501 in the insulating film 20, forming a convex portion 8 outside the cavity forming area 501 in the insulating film 20, and forming a through hole 912 penetrating the intermediate laminate 101 in a part of the bottom surface 911a of the groove 911, thereby separating the intermediate laminate 101 into a cantilever (vibration portion) 62 including the piezoelectric element 10 and a first frame portion 61 connected to a part of the cantilever 62 and surrounding the cantilever 62. The cover manufacturing step includes the following steps: the cover 3 is obtained by forming a cavity 3a to be connected to the cavity 5 through the groove 911 and the through hole 912 in the substrate 70 to be the cover 3. In the bonding step, the cover body 3 is attached to the surface (bonding surface 61a) of the vibrating device 6 on which the protrusion 8 is formed, while the bonding surface 306 of the cover body 3 and the vibrating device 6 is coated with the adhesive 100, thereby bonding the cover body 3 to the vibrating device 6. In the cavity forming step, the cavity 5 is formed on the substrate 401, thereby obtaining the support substrate 4 having the cavity 5 formed therein.

[0168] In one example of the method for manufacturing the acoustic wave generating device 1 , the acoustic wave generating device 1 having the above-mentioned effects is obtained.

[0169] In the acoustic wave generating device 1 according to one embodiment, Figure 3A , Figure 3B , Figure 4 , Figure 5 and Fig. 9 As shown, the cover 3 may have a recess 306a. In this case, a portion of the adhesive 100 may enter the recess 306a. Therefore, when the cover 3 is bonded to the substrate assembly 2 (specifically, the vibration device 6) in a state where the bonding surface 306 is coated with the adhesive 100, the recess 306a functions as a portion for releasing a portion of the adhesive 100. As a result, the adhesive 100 is less likely to overflow into the slit 9. When viewed from the Z direction, in a form in which the recess 306b is formed near the slit 9 (or near the cavity 3a) in the bonding surface 306, it is easier to prevent the adhesive 100 that is squeezed into the slit 9 due to the proximity of the bonding surface 306 and the convex portion 8 from overflowing into the slit 9.

[0170] In the acoustic wave generating device 1 and the method for manufacturing the same, a silicon oxide layer may be formed on an active layer containing silicon. Fig.10 The thermal oxidation process shown in the figure is an SOI substrate having a silicon oxide film 35 on a silicon layer 34. When the silicon layer 34 of the embodiment is used as an active layer containing silicon and the silicon oxide film 35 is used as a silicon oxide layer, the effect of forming a silicon oxide layer on the active layer containing silicon will be described.

[0171] In the acoustic wave generating device 1 having a silicon oxide film 35 on a silicon layer 34, as Figure 3A , Figure 3B , Figure 4 , Figure 5 As shown, the slit 9 penetrates the silicon oxide film 35 and the silicon layer 34 and communicates with the mold cavity 5. In order to improve the sound characteristics (especially the characteristics of the bass range), the width of the slit 9 can be narrower. In the form where the silicon oxide film 35 is provided on the silicon layer 34, it is easier to control the width of the slit 9 (specifically, the lower slit portion 92) than in the case where the silicon oxide film 35 does not exist on the silicon layer 34. Fig.24 and Fig.25 To illustrate this point. Fig.24 It is a drawing for explaining a reference example of a method of forming a hole portion in a silicon layer. Fig.25 1 is a diagram for explaining a method for forming a hole in a silicon layer when a silicon oxide layer exists on the silicon layer. Fig.24 and Fig.25 In the example, it is shown that by using Fig.24 and Fig.25 The method described below is a state in which the hole H1 is formed.

[0172] First, explain how Fig.24As shown in FIG. 1 , an example (reference example) of a method for forming a hole H in a silicon layer 34 when there is no silicon oxide film 35 on the silicon layer 34. In this case, a hole H ( Fig.24 In order to expose the hole forming region 34a corresponding to the hole H (shown by the dotted line), a resist film R is formed on the silicon layer 34 as shown by the dotted line. The silicon layer 34 is etched using the resist film R as a mask. In this case, during the etching process, as shown by the solid line, a portion of the resist film R as a mask is also removed. As a result, a hole H (hole shown by the solid line) wider than the desired hole H shown by the dotted line is formed.

[0173] Next, explain how Fig.25 FIG. 1 is an example of a method for forming the hole H in the silicon layer 34 and the silicon oxide film 35 when the silicon oxide film 35 is deposited on the silicon layer 34 . Fig.25 The hole forming region is also referred to as a hole forming region 34a.

[0174] In this case, in the laminate of the silicon layer 34 and the silicon oxide film 35, a resist film R is formed on the silicon oxide film 35 as shown by the dotted line so that the hole forming region 34a corresponding to the hole H to be formed is exposed. The silicon oxide film 35 and the silicon layer 34 are continuously etched using the resist film R as a mask. In this case, during the etching process, as shown by the solid line, a portion of the resist film R as a mask is also removed. However, since the silicon oxide film 35 has a higher selectivity than the resist film R, the desired hole H is formed in the silicon oxide film 35 before a portion of the resist film R is etched. In this way, when the desired hole H is formed in the silicon oxide film 35, the silicon oxide film 35 functions as a mask for etching the silicon layer 34. As a result, a hole H closer to the desired hole H is formed.

[0175] As described above, in the acoustic wave generating device 1, since the overflow of the adhesive 100 is suppressed, the slit width can be narrowed. In the form of the acoustic wave generating device 1 having the silicon oxide film 35 laminated on the silicon layer 34, Fig.25 As described above, the slit 9 (specifically, the lower slit portion 92) can be formed in a shape close to a desired shape. That is, even a slit 9 with a narrower width can be formed with high precision, so that the sound characteristics can be improved.

[0176] (Second embodiment)

[0177] Fig.26 It is a top view of the acoustic wave generating device (transducer) according to the second embodiment. Fig. 27 It is along Fig.26 A cross-sectional view of the acoustic wave generating device along line XXVII-XXVII in FIG. Fig.28This is a diagram of the cover body 3A according to the second embodiment as viewed from the substrate assembly side.

[0178] The acoustic wave generating device 1A of the second embodiment includes a substrate assembly 2 and a cover body 3A. The acoustic wave generating device 1A is different from the acoustic wave generating device 1A of the first embodiment in that the cover body 3 is replaced with a cover body 3A. The structure of the substrate assembly 2 included in the acoustic wave generating device 1A of the second embodiment is the same as the substrate assembly 2 described in the first embodiment. Therefore, the description of the substrate assembly 2 is omitted.

[0179] The main difference between the cover 3A and the cover 3 of the first embodiment is that a step (second step) S3 is formed on the inner surface facing the cavity 3a. The cover 3A will be described with this point as the center. Fig. 9 ) is described in detail, but a recess 306b may be formed in the cover body 3A.

[0180] The cover 3A has a cavity 3a. The cover 3A has a first portion 301, a second portion 302, a third portion 303, and a fourth portion 304 surrounding the cavity 3a. The arrangement relationship of the first portion 301, the second portion 302, the third portion 303, and the fourth portion 304 is the same as that of the first embodiment.

[0181] The inner surface 301a of the first part 301, the inner surface 302a of the second part 302, the inner surface 303a of the third part 303, and the inner surface 304a of the fourth part 304 are inner surfaces facing the cavity 3a and are also the side surfaces of the cavity 3a. The step S3 is formed on the inner surfaces 301a, 302a, 303a, and 304a. The step S3 of the inner surfaces 301a, 302a, 303a, and 304a has the same structure. Fig. 27 As shown, the step S3 of the inner surface 303a is taken as an example to illustrate the step S3.

[0182] like Fig. 27 As shown, the step S3 is formed to be recessed from the bonding surface 306 toward the side opposite to the substrate assembly 2 in the inner surface 303a. Therefore, a predetermined area (a formation area of ​​the step S3) from the bonding surface 306 in the inner surface 303a is retreated toward the side opposite to the cavity 3a (outside). The retreat amount d3 (refer to Fig.28 ) may be the same as the setback amount d1 of the inner surface 613a.

[0183] like Fig.28 As shown in FIG. 1 , a plurality of recesses 306a are formed on the joint surface 306 of the cover body 3A. Fig.28 In the example, the use of Fig. 9 Although the case where there is one recessed portion row is described above, a plurality of recessed portion rows may be formed.

[0184] An example of a method for manufacturing the acoustic wave generating device 1A having the cover 3A is the same as the method for manufacturing the acoustic wave generating device 1 described in the first embodiment except for the cover manufacturing step. Therefore, the cover manufacturing step will be described, and descriptions of other steps will be omitted.

[0185] The cover manufacturing steps of the second embodiment are also the same as those of the first embodiment. Fig. 14B As shown in the figure, a substrate 70 to be a cover body 3 having a cavity 3a is prepared. The substrate 70 includes a silicon substrate 71, a first oxide film 72 formed on the surface of the silicon substrate 71, and a second oxide film 73 formed on the back surface (the surface opposite to the surface) of the silicon substrate 71. In the processing of the substrate 70 described below, aspects related to the formation of the openings 305a and 305b are the same as those in the first embodiment, so the description is appropriately omitted.

[0186] Next, if Fig.29 As shown, the first oxide film 72 around the island region 721a is removed by photolithography and etching so that the island region 721a remains in the first oxide film 72, thereby forming an opening 72a. The second oxide film 73 around the island region 731a is removed by photolithography and etching so that the island region 731a remains in the second oxide film 73, thereby forming an opening 73a. In the second embodiment, the opening 72a is formed so that the outer periphery of the opening 72a coincides with the outer periphery 308a of the cavity formation area 308 in the substrate 70, and the opening 73a is formed so that the outer periphery of the opening 73a is located outside the outer periphery 308a. The opening 73a is formed so that the offset amount between the outer periphery of the opening 73a and the outer periphery 308a of the cavity formation area 308 is the retreat amount d3 of the step difference S3.

[0187] Next, similarly to the case of the first embodiment, a through hole 73 d 1 to be the concave portion 306 a is formed in the second oxide film 73 by photolithography and etching.

[0188] Afterwards, if Fig.30 As shown, the dielectric peeling layer 81 is bonded to the support substrate 82 on the first oxide film 72. The anti-etching film 83 is formed on the second oxide film 73. At this time, a part of the anti-etching film 83 is also filled in the through hole 73d. In the second embodiment, the anti-etching film 83 is formed in a manner covering the outer periphery of the opening 73a. More specifically, the anti-etching film 83 is formed in a manner filling the gap between the outer periphery of the opening 73a and the outer periphery 308a. Next, the silicon substrate 71 is etched using the anti-etching film 83 as a mask, thereby, as shown in FIG. Fig.31 As shown, a through hole 75 is formed which penetrates the silicon substrate 71 from the opening 73a to the opening 72b.

[0189] Next, after removing the resist film 83, the silicon substrate 71 is etched using the second oxide film 73 as a mask. As a result, the through hole 75 is extended toward the silicon substrate 71, and the recessed portion 306a is formed.

[0190] Next, the support substrate 82 and the peeling layer 81 are peeled off from the substrate 70. The island region 731a is separated from the surroundings by the through hole 75, so the region corresponding to the island region 731a in the silicon substrate 71 is removed together with the support substrate 82. Thus, the cavity 3a is formed in the substrate 70. At this stage, the openings 305a and 305b are also formed as in the case of the first embodiment. As a result, Figure 26 to Figure 28 The cover 3A is shown.

[0191] The bonding step and the cavity forming step described in the first embodiment are performed using the lid body 3A manufactured as described above and the substrate assembly semi-finished product 2A described in the first embodiment. As a result, the acoustic wave generating device 1A including the lid body 3A is obtained.

[0192] The acoustic wave generating device 1A has the same configuration as the acoustic wave generating device 1 except for the step S3, so the acoustic wave generating device 1A has the same effects as the acoustic wave generating device 1. The same applies to the method for manufacturing the acoustic wave generating device 1A.

[0193] In the acoustic wave generating device 1A, the cover 3A has a step S3. Therefore, when the cover 3A coated with the adhesive 100 is joined to the vibrating device 6, the adhesive 100 along the joint surface 306 of the cover 3A toward the slit 9 side can be released to the step S3. As a result, it is possible to suppress the adhesive 100 from overflowing to the slit 9 side.

[0194] In the embodiment where the vibrating element 6 having the step S1 and the cover 3A having the step S3 are bonded together by the adhesive 100 , measures are taken to prevent the adhesive 100 from overflowing from both the vibrating element 6 and the cover 3A, so that the adhesive 100 is less likely to overflow toward the slit 9 .

[0195] (Third embodiment)

[0196] Fig.32 It is a top view of the acoustic wave generating device (transducer) according to the third embodiment. Fig.33 It is along Fig.32 A cross-sectional view of the acoustic wave generating device along line XXXIII-XXXIII in FIG.

[0197] The acoustic wave generating device 1B of the third embodiment includes a substrate assembly 2B and a lid 3A. The lid 3A is the same as the lid 3A described in the second embodiment. Therefore, the description of the lid 3A is omitted.

[0198] The main difference between the substrate assembly 2B and the substrate assembly 2 is that the substrate assembly 2B does not have the step differences S1 and S2. That is, the substrate assembly 2B includes: a support substrate 4 having a cavity 5, and a vibration device 6A. The main difference between the structure of the vibration device 6A and the structure of the vibration device 6 is that: the slit 9 in the inner surface (inner surfaces 611a, 612a, 613a, 614a) of the first frame portion 61 does not have the step difference S1; and the second edge 622, the third edge 623 and the fourth edge 624 in the outer periphery of the cantilever 62 do not have the step difference S2; otherwise, the structure is the same as that of the vibration device 6.

[0199] Since the steps S1 and S2 are not formed, the width of the slit 9 is uniform in the extending direction (Z direction) of the slit 9 .

[0200] The acoustic wave generating device 1B is manufactured, for example, in the following manner.

[0201] The formation and use of the laminated body manufacturing steps described in the first embodiment are omitted. Fig.13 The steps of the groove portion 911 are described, and in using Fig. 14B In the step of forming the through hole 912 described above, the through hole 912 is formed in a manner penetrating from the passivation film 16 to the silicon oxide film 35, thereby obtaining the slit 9, thereby manufacturing the substrate assembly semi-finished product 2A for the acoustic wave generating device 1B. Furthermore, the cover body 3A is manufactured in the same manner as in the second embodiment. In this way, the bonding step and the cavity forming step described in the first embodiment are performed on the manufactured substrate assembly semi-finished product 2A and the cover body 3A, thereby manufacturing the acoustic wave generating device 1C.

[0202] In the sound wave generating device 1B, the vibrating device 6A has the convex portion 8, so as described in the first embodiment, the adhesive 100 toward the slit 9 is not easy to overflow. Furthermore, the cover body 3A provided in the sound wave generating device 1C has a step S3. Therefore, as described in the second embodiment, the adhesive 100 overflowing toward the slit 9 is suppressed by the step S3. Therefore, in the sound wave generating device 1B including the vibrating device 6A formed with the convex portion 8 and the cover body 3A having the step S3, the adhesive 100 is not easy to overflow toward the slit 9 side. Therefore, the adhesive 100 can be prevented from interfering with the cantilever 62. Since the adhesive overflowing toward the slit 9 side is suppressed, the width of the slit 9 can also be made narrower. As a result, sound leakage can be further prevented, and improvement of the bass characteristics is also achieved.

[0203] In the acoustic wave generating device 1B, the lid 3A may be formed with a recessed portion 306a. The effects of forming the recessed portion 306a are the same as those of the first embodiment.

[0204] (Fourth embodiment)

[0205] Fig.34 It is a top view of the sound wave generating device (transducer) according to the fourth embodiment. Fig.35 It is along Fig.34 A cross-sectional view of the acoustic wave generating device taken along line XXXV-XXXV in FIG.

[0206] The acoustic wave generating device 1C of the fourth embodiment includes a substrate assembly 2B and a cover body 3B. The substrate assembly 2B is the same as the substrate assembly 2B described in the third embodiment. Therefore, the description of the substrate assembly 2B is omitted.

[0207] The lid body 3B is different from the lid body 3A of the second embodiment (or the third embodiment) in that the size of the cavity 3a is larger than the cavity 5 when viewed from the Z direction. The lid body 3B will be described focusing on this difference.

[0208] The cover 3B includes a first portion 301 surrounding the cavity 3a, a second portion 302, a third portion 303, and a fourth portion 304. The arrangement relationship of the first portion 301, the second portion 302, the third portion 303, and the fourth portion 304 is the same as that of the first embodiment.

[0209] The inner surface 301a of the first portion 301, the inner surface 302a of the second portion 302, the inner surface 303a of the third portion 303, and the inner surface 304a of the fourth portion 304 are inner surfaces facing the cavity 3a and are also side surfaces of the cavity 3a.

[0210] As described above, when viewed from the Z direction, the size of the cavity 3a is larger than that of the cavity 5. This point is explained from the perspective of the configuration relationship between the inner surfaces 301a, 302a, 303a, 304a (corresponding to the side surfaces of the cavity 3a) when viewed from the Z direction and the inner surfaces 411, 421, 431, 441 of the support substrate 4 corresponding to the side surfaces of the cavity 5. The description of the configuration relationship is based on the state observed from the Z direction.

[0211] The inner surface 301a is retreated outward relative to the inner surface 411. The inner surface 301b is retreated outward relative to the inner surface 421. The inner surface 301c is retreated outward relative to the inner surface 431. The inner surface 301d is retreated outward relative to the inner surface 441. The retreat amount d4 (refer to Fig.34 ) is 1 μm or more and 10 μm or less. The retreat amounts of the inner surfaces 301a, 301b, 301c, and 301d relative to the corresponding inner surfaces 411, 421, 431, and 441 may be the same or different.

[0212] The cover body 3B is manufactured by the following method, that is, in the cover body manufacturing step of the second embodiment, the cavity formation area is formed larger than the cavity formation area 501. The cover body 3B manufactured in this way and the substrate assembly semi-finished product 2A manufactured in the manner described in the third embodiment are subjected to the bonding step and the cavity formation step described in the first embodiment, thereby manufacturing the acoustic wave generating device 1C.

[0213] In the acoustic wave generating device 1C, the vibrating device 6C has the convex portion 8, so as described in the first embodiment, the adhesive 100 toward the slit 9 is not easy to overflow. Furthermore, the cavity 3a of the cover 3A provided in the acoustic wave generating device 1C is larger than the mold cavity 5. In this case, Fig.35 As shown, even if the adhesive 100 toward the cavity 3a side is released along the inner surface 303a toward the side opposite to the bonding surface 306, the size of the cavity 3a is close to the size of the mold cavity 5 in consideration of the thickness of the adhesive 100 attached to the inner surface 303a. Therefore, the adhesive 100 attached to the inner surface 303a can be prevented from interfering with the cantilever 62. Here, the adhesive 100 attached to the inner surface 303a is described as an example, but the same is true for the inner surfaces 301a, 302a, and 304a. As a result, sound leakage can be prevented, and at least the characteristics of the bass range can be maintained.

[0214] Although the embodiments and variations of the present disclosure have been described above, the present invention is not limited to the exemplified embodiments. The present invention is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0215] (Variation 1)

[0216] For example, in the above-described embodiment, the acoustic wave generating device 1 is described as including one vibrating device 6, but the configuration of the acoustic wave generating device is not limited thereto. The acoustic wave generating device may include a plurality of (for example, a pair of) vibrating devices.

[0217] Fig.36 1 is a top view of the acoustic wave generating device 1D according to the first variation. Fig.37 It is along Fig.36 A cross-sectional view of the acoustic wave generating device 1D taken along line XXXVII-XXXVII in FIG. Fig.38 It is along Fig.36 A cross-sectional view of the acoustic wave generating device 1 taken along line XXXIII-XXXIII in FIG.

[0218] like Figure 36 to Figure 38As shown, the sound wave generating device 1D includes two (a pair of) vibrating devices 6, 6. Similar to the vibrating device 6 connected to the first portion 611 in the first embodiment, the sound wave generating device 1D corresponds to a form in which the vibrating device 6 is connected to the third portion 613 of the first frame portion 61 of the first embodiment. Fig.36 and Fig.37 6, the portions corresponding to the first portion 611 and the third portion 613 of the first embodiment are referred to as the first A portion 611A and the first B portion 611B. The pair of vibrating elements 6, 6 are arranged so that their free ends face each other. The free ends of the pair of vibrating elements 6, 6 are regarded as a part of the slit 9.

[0219] The acoustic wave generating device 1D is the same as the acoustic wave generating device 1 of the first embodiment except for the above-mentioned aspects. In particular, Fig.38 As shown in FIG. 1 , the configurations of the second portion 612 and the fourth portion 614 are the same as those of the first embodiment. Thus, the acoustic wave generating device 1D has the same operational effects as the acoustic wave generating device 1 .

[0220] (Variation 2)

[0221] like Fig.39 The convex portion 8A shown may be formed on the joint surface 61a in a hexagonal shape. Fig.39 613 is a diagram for explaining variation 2, and is a diagram in which a part of the third portion 613 is enlarged. Among the plurality of convex portions 8A, the plurality of convex portion rows along the extension direction of the third portion 613 may be arranged side by side in a direction orthogonal to the extension direction of the third portion 613. Fig.39 As shown, one of the two convex portion rows adjacent to each other in a direction orthogonal to the extending direction of the third portion 613 may be offset relative to the other convex portion row in the extending direction of the third portion 613. The convex portion row is formed by a plurality of convex portions 8A discretely arranged in the extending direction of the third portion 613.

[0222] Fig.39 , a variation example of the recessed portion formed on the bonding surface 306 of the cover body 3 is also illustrated. Fig.39 The recessed portion 306c shown in the example is formed on the joint surface 306 of the cover body 3 as described above, but in order to explain the arrangement relationship with the protruding portion 8A, Fig.39 The concave portion 306c is shown by a double-dotted line in FIG. Fig.39 As shown, the plan view shape of the recessed portion 306c may be a hexagon. When viewed from the Z direction, the plurality of recessed portions 306c may be formed adjacent to the convex portion 8A, but a portion of the plurality of recessed portions 306a may be formed so as to cover the convex portion 8A.

[0223] A convex portion 8B extending in the extending direction of the third portion 613 may be formed near the inner surface 613a of the third portion 613. When viewed from the Z direction, the concave portion 306c partially overlapping the convex portion 8B may have a partially cut-away hexagonal shape.

[0224] use Fig.39 , the variation examples of the convex portion formed in the third part 613 and the concave portion formed in the third part 303 in the cover body 3 are described, but the same deformation of the convex portion can also be applied to the convex portions formed in the first part 611, the second part 612 and the fourth part 614, and the same deformation of the concave portion can also be applied to the concave portions formed in the first part 301, the second part 302 and the fourth part 304 of the cover body 3.

[0225] Modifications other than the above-described Modifications 1 and 2 are also possible. For example, the cover body may not have a recessed portion for releasing the adhesive.

[0226] For example, the application examples of the transducer are not limited to sound wave generating devices (speakers or ultrasonic wave generating devices), and may be various other transducers, or MEMS mirrors or inkjet heads, for example.

[0227] One or more elements of one embodiment described above may be combined with one or more elements of another embodiment.

[0228] As described above, according to the transducer and the method for manufacturing the transducer, it is possible to appropriately ensure a gap between the vibrating portion having the piezoelectric element and the surroundings. Various embodiments of the present disclosure can be defined as follows.

[0229] (Note 1, first embodiment, second embodiment, Figure 3A , Figure 3B , Figure 8 , Fig. 27 )

[0230] A transducer having:

[0231] A supporting substrate 4 having a first cavity 5;

[0232] a vibration device 6 supported by the support substrate 4; and

[0233] The cover 3 has a second cavity 3a and is bonded to the vibration device 6 by an adhesive; and

[0234] The vibration device 6 has:

[0235] The first frame portion 61 surrounds the first cavity 5 when viewed from the cover body 3 and has a first bonding surface 61 a bonded to the cover body 3 via the adhesive 100; and

[0236] The vibration part 62 faces the first cavity 5 and has a piezoelectric element 10; and

[0237] A part of the vibration part 62 is connected to the first frame part 61.

[0238] When viewed from the joining direction of the vibrating element 6 and the cover body 3, the portion of the vibrating portion 62 other than the connection portion with the first frame portion 61 is separated from the first frame portion 61 by the slit 9 penetrating the vibrating element 6 along the joining direction.

[0239] The cover body 3 has a second frame portion 30 that surrounds the second cavity 3a and includes a second bonding surface 306 bonded to the first bonding surface 61a by the adhesive 100.

[0240] The first cavity 5 and the second cavity 3a are connected through the slit 9.

[0241] The first joint surface 61a is provided with a protrusion 8 protruding toward the second joint surface 306.

[0242] A first step S1 that is recessed from the first joint surface 61 a toward the side opposite to the cover body 3 is formed on the inner surface 615 of the first frame portion 61 that faces the slit 9 .

[0243] (Note 2, Second Implementation Method, Fig. 27 and Fig.28 )

[0244] A transducer as described in Note 1, wherein

[0245] A second step S3 recessed toward the side opposite to the vibrator element 6 is formed on the inner surfaces 301 a , 302 a , 303 a , and 304 a of the second bonding surface 306 that face the second cavity 3 a .

[0246] (Supplementary Note 3, 1st to 3rd Embodiments, Figure 3A , Figure 3B , Fig. 27 , Fig.35 )

[0247] A transducer as described in Note 1 or 2, wherein

[0248] A plurality of recessed portions 306 a are formed on the second joining surface 306 .

[0249] (Note 4, 1st to 3rd embodiments, Figure 3A , Figure 3B , Fig. 27 , Fig.35)

[0250] A transducer as described in any one of Notes 1 to 3, wherein

[0251] The vibration device 6 has:

[0252] an active layer 32, which is laminated on the support substrate 4 and comprises silicon; and

[0253] The silicon oxide layer 33 is deposited on the side of the active layer 32 opposite to the supporting substrate.

[0254] (Note 5, Implementation Method 3, Fig.32 and Fig.33 )

[0255] A transducer having:

[0256] A supporting substrate 4 having a first cavity 5;

[0257] A vibration device 6A supported by the support substrate 4; and

[0258] The cover 3A has a second cavity 3a and is bonded to the vibration device 6A via an adhesive 100; and

[0259] The vibration device 6A has:

[0260] The first frame portion 61 surrounds the first cavity 5 when viewed from the cover body 3A, and has a first bonding surface 61a bonded to the cover body 3A by the adhesive 100; and

[0261] The vibration part 62 faces the first cavity 5 and has a piezoelectric element 10; and

[0262] A part of the vibration part 62 is connected to the first frame part 61.

[0263] When viewed from the joining direction of the vibrating element 6A and the cover body 3A, the portion of the vibrating portion 62 other than the connection portion with the first frame portion 61 is separated from the first frame portion 61 by the slit 9 penetrating the vibrating element 6A along the joining direction.

[0264] The cover 3A has a second frame portion 30 that surrounds the second cavity 3a and includes a second bonding surface 306 bonded to the first bonding surface 61a by the adhesive 100.

[0265] The first cavity 5 and the second cavity 3a are connected through the slit 9.

[0266] The first joint surface 61a is provided with a protrusion 8 protruding toward the second joint surface 306.

[0267] Inner surfaces 301 a , 302 a , 303 a , and 304 a of the second bonding surface 306 facing the second cavity 3 a are formed with a step S3 that is recessed toward the side opposite to the vibrator element 6A.

[0268] (Note 6, 4th embodiment, Fig.34 , Fig.35 )

[0269] A transducer having:

[0270] A supporting substrate 4 having a first cavity 5;

[0271] A vibration device 6A supported by the support substrate 4; and

[0272] The cover 3B has a second cavity 3a and is bonded to the vibration device 6A by an adhesive 100; and

[0273] The vibration device 6A has:

[0274] The first frame portion 61 surrounds the first cavity 5 when viewed from the cover body 3B, and has a first bonding surface 61a bonded to the cover body 3B via the adhesive 100; and

[0275] The vibration part 62 faces the first cavity 5 and has a piezoelectric element 10; and

[0276] A part of the vibration part 62 is connected to the first frame part 61.

[0277] When viewed from the joining direction of the vibrating element 6A and the cover body 3B, the portion of the vibrating portion 62 other than the connection portion with the first frame portion 61 is separated from the first frame portion 61 by the slit 9 penetrating the vibrating element 6A along the joining direction.

[0278] The cover 3B has a second frame portion 30 that surrounds the second cavity 3a and includes a second bonding surface 306 bonded to the first bonding surface 61a by the adhesive 100.

[0279] The first cavity 5 and the second cavity 3a are connected through the slit 9.

[0280] The first joint surface 61a is provided with a protrusion 8 protruding toward the second joint surface 306.

[0281] When viewed from the joining direction, the size of the second cavity 3 a is larger than the size of the first cavity 5 .

[0282] (Note 7, First Implementation Method, Figure 10 to Figure 23 )

[0283] A method for manufacturing a transducer, the transducer comprising: a support substrate 4 having a first cavity 5; a vibrating element 6 laminated on the support substrate 4; and a cover 3 having a second cavity 3a and bonded to the vibrating element 6 by an adhesive; and the method for manufacturing the transducer comprises:

[0284] a laminate manufacturing step of forming a laminate 2A of the first substrate 401 to be the supporting substrate 4 and the vibration device 6;

[0285] A cover body manufacturing step, manufacturing the cover body 3;

[0286] a bonding step of bonding the cover 3 to the vibration device 6; and

[0287] a cavity forming step of forming a first cavity 5 in a first cavity forming predetermined region 501 of the first substrate 401; and

[0288] The laminate manufacturing step comprises the following steps:

[0289] An intermediate laminate 101 is formed, wherein the intermediate laminate 101 comprises: a vibration film forming layer 7 laminated on the first substrate 401; a piezoelectric element 10 disposed above the first cavity forming area 501 in the vibration film forming layer 7; and an insulating film 20 covering the piezoelectric element 10 and the vibration film forming layer 7;

[0290] In the intermediate laminate 101, a groove 911 is formed along the outer peripheral edge 501a from the insulating film 20 side in a region other than a portion of the outer peripheral edge 501a of the first cavity forming region 501;

[0291] In the insulating film 20 , a convex portion 8 is formed outside the first cavity forming area 501 ; and

[0292] The through hole 912 penetrating the intermediate laminate 101 is formed in a part of the bottom surface 911a of the groove 911, so that the intermediate laminate 101 is separated into a vibration part 62 including the piezoelectric element 10 and a frame part 61 connected to the vibration part 62 and surrounding the vibration part 62, thereby obtaining the vibration device 6; and

[0293] The cover manufacturing step includes the following steps: forming a second cavity 3a which is to be communicated with the first cavity 5 through the groove 911 and the through hole 912 on the second substrate 70 which is to be the cover 3, thereby obtaining the cover 3;

[0294] In the bonding step, the cover body 3 is attached to the surface of the vibrating device 6 on which the protrusion 8 is formed, while the bonding surface 306 of the cover body 3 and the vibrating device 6 is coated with the adhesive 100, thereby bonding the cover body 3 to the vibrating device 6;

[0295] In the cavity forming step, the first cavity 5 is formed on the first substrate 401 , thereby obtaining the supporting substrate 4 having the first cavity 5 formed therein.

[0296] (Note 8, First Implementation Method, Fig.10 )

[0297] A method for manufacturing a transducer according to Note 7, wherein

[0298] The vibration film forming layer 7 has:

[0299] an active layer 32, which is laminated on the support substrate 4 and comprises silicon; and

[0300] The silicon oxide layer 33 is formed on the side of the active layer 32 opposite to the supporting substrate 4 .

[0301] [Explanation of Symbols]

[0302] 1,1A,1B,1C,1D: Sound wave generating device (transducer)

[0303] 2,2B: Substrate assembly

[0304] 2A: Substrate assembly semi-finished product

[0305] 3,3A,3B: Cover

[0306] 3a: Cavity (Second Cavity)

[0307] 4: Support substrate

[0308] 5: Mold cavity (first cavity)

[0309] 5a: Opening

[0310] 6,6A,6C: Vibration devices

[0311] 7: Vibration membrane forming layer

[0312] 7a: Vibrating membrane

[0313] 8:convex part

[0314] 8a: Core

[0315] 9: Slit

[0316] 9a: Part 1

[0317] 9b: Part 2

[0318] 9c: Part 3

[0319] 10: Piezoelectric element

[0320] 11: Lower electrode

[0321] 12: Piezoelectric film

[0322] 13: Upper electrode

[0323] 14A: 1st hydrogen barrier film

[0324] 14B: Second hydrogen barrier film

[0325] 15: Interlayer insulation film

[0326] 16: Passivation film

[0327] 16a: Upper pad opening

[0328] 16b: Lower pad opening

[0329] 17: Upper wiring

[0330] 17a: Upper pad

[0331] 17b: 1st wiring section

[0332] 17c: Second wiring section

[0333] 18: Lower wiring

[0334] 18a: Lower pad

[0335] 18b: 1st wiring section

[0336] 18c: Second wiring section

[0337] 19a: Contact hole

[0338] 19b: Contact hole

[0339] 20: Insulation film

[0340] 30a: Groove

[0341] 31: Silicon oxide film

[0342] 32: Silicon substrate

[0343] 33: Oxide film (silicon oxide layer)

[0344] 34: Silicon layer

[0345] 34a: hole forming area

[0346] 35: Silicon oxide film

[0347] 41:Part 1

[0348] 42: Part 2

[0349] 43: Part 3

[0350] 44:Part 4

[0351] 61: 1st frame

[0352] 62: Cantilever (vibration part)

[0353] 70: Substrate (second substrate)

[0354] 71: Silicon substrate

[0355] 72: 1st oxide film

[0356] 72a: Opening

[0357] 72b: Opening

[0358] 72c: Opening

[0359] 73a: Opening

[0360] 73: Second oxide film

[0361] 73b: Opening

[0362] 73c: Opening

[0363] 73d:Through hole

[0364] 75:Through hole

[0365] 81: Peeling layer

[0366] 82: Support substrate

[0367] 83: Anti-corrosion film

[0368] 91: Upper slit

[0369] 92: Lower slit part

[0370] 100: Adhesive

[0371] 101: Intermediate layer

[0372] 301: Part 1

[0373] 301a: Inner surface

[0374] 301b: Inner surface

[0375] 301c: Inner surface

[0376] 301d:Inner surface

[0377] 302: Part 2

[0378] 302a: Inner surface

[0379] 303: Part 3

[0380] 303a: Inner surface

[0381] 304: Part 4

[0382] 304a: Inner surface

[0383] 305a: Opening

[0384] 305b: Opening

[0385] 306: Joint surface

[0386] 306a: groove

[0387] 306a1: 1st groove

[0388] 306a2: Second groove

[0389] 308: Cavity forms a predetermined area

[0390] 308a: outer periphery

[0391] 401: Substrate (first substrate)

[0392] 411: Inner surface

[0393] 421: Inner surface

[0394] 431: Inner surface

[0395] 441: Inner surface

[0396] 501: cavity forming predetermined region (first cavity forming predetermined region)

[0397] 501a: Outer periphery

[0398] 611: Part 1

[0399] 611A: Section 1A

[0400] 611B: Part 1B

[0401] 612: Part 2

[0402] 613: Part 3

[0403] 614: Part 4

[0404] 61a: Joint surface

[0405] 621: The first edge

[0406] 622: The second edge

[0407] 623: The third edge

[0408] 624: The 4th Edge

[0409] 611a: Inner surface

[0410] 612a: Inner surface

[0411] 613a: Inner surface

[0412] 614a:Inner surface

[0413] 615: Inner surface

[0414] 721a: Island area

[0415] 721b: Island area

[0416] 721c: Island area

[0417] 731a: Island area

[0418] 731b: Island area

[0419] 731c: Island area

[0420] 911: Groove

[0421] 911a: Bottom

[0422] 912:Through hole

[0423] A: Area

[0424] S1: Step Difference

[0425] S2: Step Difference

[0426] S3: Step Difference

[0427] d1: Retreat amount

[0428] d2: Retreat amount

[0429] d3: Retreat amount

[0430] d4: Retreat amount

[0431] H: Hole

[0432] H1: Hole

[0433] R: Anti-corrosion film

[0434] W1: Width

[0435] W2: width.

Claims

1. A transducer having: A supporting substrate having a first cavity; a vibration device supported by the support substrate; and The cover has a second cavity and is bonded to the vibration device by an adhesive; and The vibration device has: a first frame portion, which surrounds the first cavity when viewed from the cover body and has a first joining surface joined to the cover body by the adhesive; and a vibrating portion facing the first cavity and having a piezoelectric element; and A part of the vibration part is connected to the first frame part, When viewed from the joining direction between the vibration device and the cover body, the portion of the vibration portion other than the connection portion with the first frame portion is separated from the first frame portion by a slit penetrating the vibration device along the joining direction. The cover has a second frame portion that surrounds the second cavity and includes a second bonding surface bonded to the first bonding surface by the adhesive. The first cavity and the second cavity are connected through the slit, A convex portion protruding toward the second joining surface is formed on the first joining surface, A first step is formed on an inner surface of the first frame portion that faces the slit and is recessed from the first joining surface toward a side opposite to the cover body.

2. The transducer according to claim 1, wherein A second step that is recessed toward a side opposite to the vibration element is formed on an inner surface of the second bonding surface that faces the second cavity.

3. The transducer according to claim 1 or 2, wherein A plurality of recessed portions are formed on the second joining surface.

4. The transducer according to any one of claims 1 to 3, wherein The vibration device has: an active layer, laminated on the support substrate and comprising silicon; and The silicon oxide layer is stacked on the side of the active layer opposite to the supporting substrate.

5. A transducer comprising: A supporting substrate having a first cavity; a vibration device supported by the support substrate; and The cover has a second cavity and is bonded to the vibration device by an adhesive; and The vibration device has: a first frame portion, which surrounds the first cavity when viewed from the cover body and has a first joining surface joined to the cover body by the adhesive; and a vibrating portion facing the first cavity and having a piezoelectric element; and A part of the vibration part is connected to the first frame part, When viewed from the joining direction between the vibration device and the cover body, the portion of the vibration portion other than the connection portion with the first frame portion is separated from the first frame portion by a slit penetrating the vibration device along the joining direction. The cover has a second frame portion that surrounds the second cavity and includes a second bonding surface bonded to the first bonding surface by the adhesive. The first cavity and the second cavity are connected through the slit, A convex portion protruding toward the second joining surface is formed on the first joining surface, The inner surface of the second bonding surface facing the second cavity is formed with a step recessed toward a side opposite to the vibration element.

6. A transducer comprising: A supporting substrate having a first cavity; a vibration device supported by the support substrate; and The cover has a second cavity and is bonded to the vibration device by an adhesive; and The vibration device has: a first frame portion, which surrounds the first cavity when viewed from the cover body and has a first joining surface joined to the cover body by the adhesive; and a vibrating portion facing the first cavity and having a piezoelectric element; and A part of the vibration part is connected to the first frame part, When viewed from the joining direction between the vibration device and the cover body, the portion of the vibration portion other than the connection portion with the first frame portion is separated from the first frame portion by a slit penetrating the vibration device along the joining direction. The cover has a second frame portion that surrounds the second cavity and includes a second bonding surface bonded to the first bonding surface by the adhesive. The first cavity and the second cavity are connected through the slit, A convex portion protruding toward the second joining surface is formed on the first joining surface, When viewed from the joining direction, a size of the second cavity is larger than a size of the first cavity.

7. A method for manufacturing a transducer, the transducer comprising: a support substrate having a first cavity; a vibration device laminated on the support substrate; and a cover having a second cavity and bonded to the vibration device by an adhesive; and the method for manufacturing the transducer comprises: a laminate manufacturing step of forming a laminate of a first substrate to be the supporting substrate and the vibration device; A cover manufacturing step, manufacturing the cover; A bonding step of bonding the cover body to the vibration device; as well as a cavity forming step of forming a first cavity in a first cavity formation predetermined region of the first substrate; and The laminate manufacturing step comprises the following steps: forming an intermediate laminated body, the intermediate laminated body comprising: a vibration film forming layer laminated on the first substrate; and a piezoelectric element disposed above the first cavity forming predetermined region in the vibration film forming layer; as well as an insulating film covering the piezoelectric element and the vibration film forming layer; In the intermediate laminate, a groove is formed along the outer periphery from the insulating film side in a region other than a portion of the outer periphery of the region where the first cavity is to be formed; forming a convex portion in the insulating film outside the first cavity formation planned region; as well as The vibrating device is obtained by forming a through hole penetrating the intermediate laminate body in a portion of the bottom surface of the groove portion, so as to separate the intermediate laminate body into a vibrating portion including the piezoelectric element and a frame portion that is partially connected to the vibrating portion and surrounds the vibrating portion; and The cover manufacturing step includes the following steps: forming a second cavity that is to be communicated with the first cavity through the groove and the through hole on a second substrate that is to be the cover, thereby obtaining the cover; In the bonding step, the cover body is attached to the surface of the vibrating device on which the convex portion is formed, while an adhesive is applied to the bonding surface of the cover body with the vibrating device, thereby bonding the cover body to the vibrating device; In the cavity forming step, the first cavity is formed in the first substrate, thereby obtaining a supporting substrate having the first cavity formed therein.

8. The method for manufacturing a transducer according to claim 7, wherein The vibration film forming layer has: an active layer, laminated on the support substrate and comprising silicon; and A silicon oxide layer is formed on a side of the active layer opposite to the supporting substrate.

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