Piezoelectric element unit, method for manufacturing the same, and piezoelectric drive device

Abstract

To provide a technique for suppressing increase in a manufacturing cost and achieving conduction among a plurality of piezoelectric elements.SOLUTION: A piezoelectric element unit includes: a semiconductor substrate having a first main surface, a second main surface, and an end portion connecting the first main surface and the second main surface; a piezoelectric element formed on the first main surface; a first insulating film formed on the piezoelectric element and extending up to on the end portion; a wiring layer formed on the first insulating film and electrically connected to the piezoelectric element; and a second insulating film formed on the second main surface. The first insulating film has a first insulating film end region formed on the end portion. The wiring layer extends up to on the first insulating film has a first insulating film end region and has a wiring layer end region formed on the first insulating film end region. The end portion has an end face crossing the first main surface and a protrusion that protrudes outward from the end face.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a piezoelectric element unit, a piezoelectric driving device, and a method for manufacturing a piezoelectric element unit.

Background Art

[0002] Conventionally, in a device configured by stacking a plurality of semiconductor elements, in order to electrically connect the semiconductor elements to each other, a TSV (Through-silicon via) technique has been used (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when using the TSV technique in the manufacture of a device, the number of manufacturing steps inevitably increases, making it difficult to reduce the manufacturing cost. This problem is common not only to semiconductor elements but also to piezoelectric elements.

Means for Solving the Problems

[0005] According to one aspect of the present disclosure, a piezoelectric element unit is provided. The piezoelectric element unit includes a semiconductor substrate having a first main surface, a second main surface located on the side opposite to the first main surface, and an end portion connecting the first main surface and the second main surface; a piezoelectric element formed on the first main surface; a first insulating film formed on the piezoelectric element and extending up to the end portion; a wiring layer formed on the first insulating film and electrically connected to the piezoelectric element; and a second insulating film formed on the second main surface. The first insulating film has a first insulating film end region formed on the end portion. The wiring layer extends up to the first insulating film end region and has a wiring layer end region formed on the first insulating film end region. The end portion has an end surface intersecting the first main surface, and a protruding portion protruding outward from the end surface between the end surface and the second main surface.

Brief Description of the Drawings

[0006]

Figure 1

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Embodiments for Carrying Out the Invention

[0007] A. First Embodiment: A1. Structure of the Piezoelectric Element Unit: FIG. 1 is a perspective view of the piezoelectric element unit 6. FIG. 2 is a sectional view of the piezoelectric element unit laminate 1006 in which the piezoelectric element units 6 are laminated and the circuit board 4 is joined. In FIG. 1, arrows indicating the X, Y, and Z directions orthogonal to each other are shown. The arrows indicating the X, Y, and Z directions are also appropriately shown in other figures so that the illustrated directions correspond to those in FIG. 1. In the following description, when specifying the direction, the direction indicated by the arrow in each figure is defined as “+” and the opposite direction as “-”, and plus and minus signs are used in combination for direction notation. Note that the schematic diagrams shown after FIG. 1 are diagrams for clearly showing the technical features of the piezoelectric element unit 6 and do not accurately show the dimensions of each part.

[0008] The piezoelectric element unit 6 includes a semiconductor substrate 20, a piezoelectric element 40, a first insulating film 50, a second insulating film 60, a wiring layer 70, and an upper insulating film 80. The semiconductor substrate 20 has a first main surface 21, a second main surface 22 located on the side opposite to the first main surface 21, and an end portion 23 connecting the first main surface 21 and the second main surface 22. As the semiconductor substrate 20, a silicon substrate, a silicon carbide substrate, a compound semiconductor substrate, or the like can be used. In the present embodiment, a silicon substrate is used as the semiconductor substrate 20. The semiconductor substrate 20 includes an oxide film formed on the first main surface 21 and an oxide film formed on the second main surface 22, but the illustration of this oxide film is omitted in FIG. 1. Similarly, the illustration of the oxide film included in the semiconductor substrate 20 is omitted in the figures after FIG. 2. In the following description, the first insulating film 50, the second insulating film 60, each layer constituting the piezoelectric element 40, the wiring layer 70, and the upper insulating film 80 may be collectively referred to as "layers". The stacking direction of the layers on the first main surface 21 is the Z direction.

[0009] The end portion 23 has a first end surface 23a as an end surface intersecting the first main surface 21 and a protruding portion 24. Here, in the present disclosure, "intersecting" includes the case where two surfaces actually intersect and the case where the extended virtual surfaces of the two surfaces intersect. The protruding portion 24 is disposed between the first end surface 23a and the second main surface 22. The protruding portion 24 protrudes outward from the first end surface 23a. The protruding portion 24 includes a second end surface 23b as an upper surface and a third end surface 23c as the tip of the protruding portion 24. The second end surface 23b connects the first end surface 23a and the second end surface 23b. By forming the protruding portion 24, as will be described in detail later, the bonding force of the bonding agent 8 for bonding the circuit board 4 to the piezoelectric element unit 6 can be improved.

[0010] The length of the first end surface 23a in the Z direction is about several tens of μm to several hundreds of μm. In the present embodiment, the thickness of the semiconductor substrate 20 is about 60 μm. Also, the length of the first end surface 23a in the Z direction, the length of the second end surface 23b in the Y direction, and the length of the third end surface 23c in the Z direction are all about 30 μm. Note that the respective lengths from the first end surface 23a to the third end surface 23c are not limited to this.

[0011] In the figures shown after FIG. 1, for the sake of convenience, the plane intersecting the Y direction of each layer is depicted as a plane orthogonal to the first main surface 21, but it does not accurately show the actual shape. For example, in FIG. 1, the first end surface 23a is depicted as intersecting the first main surface 21 at a right angle, but actually, the first end surface 23a is inclined with respect to the Z direction. Specifically, the first end surface 23a is inclined so as to approach the third end surface 23c as it approaches the second main surface 22. Other end surfaces, for example, the end surfaces of the piezoelectric element 40 that intersect the Y direction, are also inclined with respect to the Z direction. Also, in the figures shown after FIG. 1, for the sake of convenience, the surfaces of each layer are depicted as straight lines, but it does not indicate that they are smooth surfaces. For example, as will be described later, scallops are formed on the first end surface 23a.

[0012] The piezoelectric element 40 is formed on the first main surface 21. The piezoelectric element 40 has a first electrode layer 41, a piezoelectric layer 42, and a second electrode layer 43. The first electrode layer 41, the piezoelectric layer 42, and the second electrode layer 43 are laminated on the first main surface 21 in this order. In the present embodiment, the first electrode layer 41 functions as a common electrode to which a common signal is input. The second electrode layer 43 functions as an individual electrode to which a drive signal is input. When a voltage is applied between the first electrode layer 41 and the second electrode layer 43, the piezoelectric element 40 deforms. In the present embodiment, when an alternating voltage is applied between the first electrode layer 41 and the second electrode layer 43, the piezoelectric element unit 6 vibrates.

[0013] The first insulating film 50 is formed on the piezoelectric element 40. In the present embodiment, the thickness of the piezoelectric element 40 is about 1 μm or more and 10 μm or less. The first insulating film 50 extends up to the end portion 23. The first insulating film 50 has a first insulating film end region 50a formed on the end portion 23.

[0014] The wiring layer 70 is formed on the first insulating film 50 and is electrically connected to the piezoelectric element 40. Specifically, the wiring layer 70 is electrically connected to the first electrode layer 41 or the second electrode layer 43. The wiring layer 70 is in contact with the second electrode layer 43 or the first electrode layer 41 through the contact hole 50b formed in the first insulating film 50. The wiring layer 70 extends up to the end region 50a of the first insulating film. The wiring layer 70 has a wiring layer end region 70a formed on the end region 50a of the first insulating film. The wiring layer end region 70a is exposed at the end 23. Thus, as will be described in detail later, it can be electrically connected to the circuit board 4 shown in FIG. 2.

[0015] The second insulating film 60 is formed on the second main surface 22. The second insulating film 60 extends up to the wiring layer end region 70a. The second insulating film 60 has a second insulating film end region 60a formed on the wiring layer end region 70a.

[0016] A2. Manufacturing method of piezoelectric element unit: FIG. 3 is a flowchart of a manufacturing process for realizing the manufacturing method of the piezoelectric element unit 6. FIG. 4 is a diagram for explaining the preparation step S1 to the second groove formation step S5. FIG. 5 is a diagram for explaining the first insulating film formation step S7 to the grinding step S15. FIG. 6 is a diagram for explaining the ashing step S17 to the adhesive removal step S23.

[0017] In the preparation step S1 of FIG. 3, the laminate 1000 is prepared. As shown by "S1" in FIG. 4, the laminate 1000 includes the semiconductor substrate 1020 and the piezoelectric element 40. In this embodiment, the semiconductor substrate 1020 is a silicon wafer. In this embodiment, the case where two piezoelectric elements 40 are formed on the semiconductor substrate 1020 will be exemplified and described.

[0018] The semiconductor substrate 1020 has a first main surface 21 and a second main surface 22 located on the side opposite to the first main surface 21. The semiconductor substrate 1020 includes an oxide film (not shown) formed on the first main surface 21 and an oxide film (not shown) formed on the second main surface 22. The piezoelectric element 40 is formed on the first main surface 21. The piezoelectric element 40 has a first electrode layer 41, a piezoelectric layer 42, and a second electrode layer 43.

[0019] As the material of the first electrode layer 41, any highly conductive material such as Al (aluminum), Ni (nickel), Au (gold), Pt (platinum), Ir (iridium), Cu (copper), etc. can be used. As the film formation method of the first electrode layer 41, for example, a sputtering method, a vacuum evaporation method, etc. can be used.

[0020] As the piezoelectric layer 42, lead zirconate titanate (PZT), barium titanate, lead titanate, potassium niobate, lithium niobate, lithium tantalate, sodium tungstate, zinc oxide, barium strontium titanate (BST), strontium bismuth tantalate (SBT), lead metaniobate, lead zinc niobate, lead scandium niobate, etc. can be used. As the manufacturing method of the piezoelectric layer 42, a sol-gel method, a sputtering method, a method of placing a bulk body, etc. can be used. Among these, the sol-gel method is preferable because a thin piezoelectric layer 42 can be easily formed. The second electrode layer 43 is formed in the same manner as the first electrode layer 41.

[0021] As shown in FIG. 3, in the first groove formation step S3, the first groove 25 is formed. As shown by "S3" in FIG. 4, the first groove 25 is a groove formed on the first main surface 21 of the semiconductor substrate 1020. For the formation of the first groove 25, a Bosch process is used. Specifically, the Bosch process is a method of forming a deep groove with a high aspect ratio by repeating a process of etching by isotropic etching, a process of forming a protective film, and a process of etching by anisotropic etching.

[0022] Since the first groove 25 is formed using a Bosch process, as shown enlarged in "S3" of FIG. 4, scallops with an uneven structure arranged in the Z direction are formed on the side surface of the first groove 25. Note that the side surface of the first groove 25 is the surface that becomes the first end face 23a of the piezoelectric element unit 6 shown in FIG. 1. Since scallops are formed on the side surface of the first groove 25, the adhesion of the film formed on the side surface of the first groove 25 can be improved in subsequent processes.

[0023] Also, since it is formed using a Bosch process, the bottom surface of the first groove 25 has a deep connection part with the side surface of the first groove 25 and the central part is raised. The bottom surface of the first groove 25 curves so that the central part protrudes with respect to the peripheral part, and in the peripheral part, it curves so that the connection part with the side surface of the first groove 25 further recesses. Note that the bottom surface of the first groove 25 is the surface that becomes the second end face 23b of the piezoelectric element unit 6 shown in FIG. 1. The difference in the Z-direction position between the peripheral part of the bottom surface of the first groove 25 and the center of the bottom surface of the first groove 25 is about several micrometers.

[0024] In the second groove forming step S5 of FIG. 3, a second groove 26 is further formed at the bottom of the first groove 25. Note that the side surface of the second groove 26 is the surface that becomes the third end face 23c of the piezoelectric element unit 6 shown in FIG. 1. As shown in "S5" of FIG. 4, the second groove 26 is a groove formed on the bottom surface of the first groove 25. The width of the second groove 26 is set to be smaller than the width of the first groove 25. Thereby, the protruding part 24 shown in FIG. 1 can be formed. The second groove 26 is formed using a Bosch process in the same manner as the first groove 25. Therefore, scallops are formed on the side surface of the second groove 26. Since scallops are formed, the adhesion of the film formed on the side surface of the second groove 26 can be improved in subsequent processes in the same manner as the side surface of the first groove 25.

[0025] As described above, the bottom surface of the first groove 25 curves such that the central portion protrudes with respect to the peripheral portion, and in the peripheral portion, it further curves so as to be recessed. Therefore, as shown by "S5" in FIG. 4, the second end face 23b curves so as to draw a curve from the connection portion 24d between the first end face 23a and the second end face 23b toward the third end face 23c. Specifically, the second end face 23b has a shape that curves so as to be recessed in the Z direction. Thereby, as will be described in detail later, it is possible to make it difficult to peel off the circuit board 4 mounted on the piezoelectric element unit 6.

[0026] In the first insulating film forming step S7 of FIG. 3, the first insulating film 50 is formed. As the material of the first insulating film 50, an organic material or an inorganic material can be used. As the manufacturing method of the first insulating film 50, a CVD (chemical vapor deposition) method, a vacuum evaporation method, a sputtering method, a coating method, etc. can be used. In the present embodiment, TEOS (Tetra-Ethyl-Orso-Silicate) is used as the first insulating film 50. As shown by "S7" in FIG. 5, the first insulating film 50 is formed so as to cover the piezoelectric element 40, the side surface and the bottom surface of the first groove 25 as the first exposed surface of the first groove 25, and the side surface and the bottom surface of the second groove 26 as the second exposed surface of the second groove 26. Thereafter, contact holes are formed in the first insulating film 50 by a patterning technique using photolithography.

[0027] In the wiring layer forming step S9 of FIG. 3, the wiring layer 70 is formed. The wiring layer 70 is formed, for example, in the same manner as the second electrode layer 43. The wiring layer 70 is formed so as to cover the first insulating film 50. Thereafter, by a patterning technique using photolithography, the wiring layer 70 is processed into a plurality of patterns.

[0028] In the upper insulating film forming step S11 of FIG. 3, an upper insulating film 80 is formed on the wiring layer 70. The upper insulating film 80 is formed only in a desired region using photolithography. As a result, as shown at "S11" in FIG. 5, the upper insulating film 80 is formed mainly on the wiring layer 70, which is a region excluding the first groove 25 and the second groove 26. Note that the material and manufacturing method of the upper insulating film 80 are the same as those of the first insulating film 50.

[0029] Note that after the upper insulating film forming step S11, a step of forming a gold plating layer on the surface of the wiring layer 70 may be performed. By forming the gold plating layer, good electrical connection with the circuit board 4 described later can be achieved.

[0030] In the support substrate bonding step S13 of FIG. 3, the semiconductor substrate 1020 and the support substrate 1040 are bonded using an adhesive 1030. Specifically, as shown at "S13" in FIG. 5, the support substrate 1040 disposed to face the first main surface 21 and the laminate 1000 are bonded via the adhesive 1030.

[0031] As the support substrate 1040, a substrate having light transmissibility or ultraviolet transmissibility is used. In the present embodiment, a glass substrate is used as the support substrate 1040. As the adhesive 1030, a photo-curable liquid adhesive or an ultraviolet-curable liquid adhesive is used. Light for curing the adhesive 1030 is irradiated from the support substrate 1040 side with the adhesive 1030 filled between the support substrate 1040 and the laminate 1000. As a result, the light transmitted through the support substrate 1040 irradiates the adhesive 1030, and the support substrate 1040 and the laminate 1000 are bonded. By using a liquid adhesive as the adhesive 1030, the adhesive 1030 is filled around the piezoelectric element 40 and inside the first groove 25 and the second groove 26. Therefore, the laminate 1000 and the support substrate 1040 are integrated, and the rigidity can be increased.

[0032] In the grinding process S15 of FIG. 3, the second main surface 22 of the semiconductor substrate 1020 is ground until the second groove 26 is penetrated. As shown in "S15" of FIG. 5, when the grinding process S15 is performed, the second groove 26 penetrates and becomes a through hole. Further, the first insulating film 50 and the wiring layer 70 formed on the side surface of the second groove 26 and the adhesive 1030 filled inside the second groove 26 are exposed on the second main surface 22 side. The exposed end surface of the wiring layer 70 is referred to as a wiring end surface 70b. By grinding the semiconductor substrate 1020 thinner, the piezoelectric element unit 6 can be deformed more easily. Since the laminate 1000 is supported by the support substrate 1040, the semiconductor substrate 1020 can be ground while suppressing the occurrence of chipping, cracking, etc. on the semiconductor substrate 1020.

[0033] In the ashing process S17 of FIG. 3, ashing treatment is performed on the second main surface 22 of the laminate 1000 as a processing surface. As a result, as shown in "S17" of FIG. 6, a part of the adhesive 1030 exposed in the grinding process is removed, and the exposed surface of the adhesive 1030 retreats. As a result, as shown in an enlarged view in FIG. 6, a part of the surface of the wiring layer 70 covered with the adhesive 1030 and in contact with the adhesive 1030 can be exposed. As the ashing treatment, for example, O 2 ashing, plasma treatment, or the like can be used.

[0034] In the etching process S19 of FIG. 3, the second main surface 22 is etched as a processing surface to retreat the wiring end surface 70b. As shown in "S19" of FIG. 6, the wiring end surface 70b retreats to before the exposed surface of the adhesive 1030. By the etching process S19, the metal material attached to the second main surface 22 can be removed. Therefore, a decrease in the insulation of the semiconductor substrate 1020 can be prevented. As the etching treatment, for example, a wet etching method or a dry etching method can be used.

[0035] In the second insulating film forming step S21 of FIG. 3, the second insulating film 60 is formed so as to cover the second main surface 22 and the wiring end face 70b. The material and manufacturing method of the second insulating film 60 are the same as those of the first insulating film 50. As shown in "S21" of FIG. 6, the second insulating film 60 is also formed to cover the exposed surface of the adhesive 1030 and the exposed end face of the first insulating film 50.

[0036] In the adhesive removing step S23 of FIG. 3, the adhesive 1030 is removed. Specifically, by attaching a tape to the second main surface 22, the semiconductor substrate 1020 is fixed and the laser light is irradiated from the support substrate 1040 side, so that the adhesive 1030 is peeled off from the laminate 1000. Along with this, the second insulating film 60 formed on the adhesive 1030 is separated from the second insulating film 60 formed on the second main surface 22. As shown in "S23" of FIG. 6, by removing the support substrate 1040 and the adhesive 1030 from the laminate 1000, the piezoelectric element unit 6 is obtained.

[0037] As described above, the side surface of the first groove 25 is the first end face 23a of the piezoelectric element unit 6. The bottom surface of the first groove 25 is the second end face 23b of the piezoelectric element unit 6. The side surface of the second groove 26 is the third end face 23c of the piezoelectric element unit 6. On the first end face 23a of the piezoelectric element unit 6, a scallop in which uneven structures are arranged in the direction from the first main surface 21 toward the second main surface 22 is formed along with the formation of the first groove 25. The second end face 23b of the piezoelectric element unit 6 is curved so as to draw a curve from the connection part 24d between the first end face 23a and the protrusion 24 toward the third end face 23c. Further, the wiring end face 70b is the end face in the direction from the first main surface 21 to the second main surface 22 of the piezoelectric element unit 6. By performing the etching step S19, the wiring end face 70b of the piezoelectric element unit 6 retreats more than the second main surface 22.

[0038] In the manufacturing process, for example, in the grinding process S15, the semiconductor substrate 20 is subjected to an external force. Therefore, the shape of the protruding portion 24 is preferably a shape that does not cause cracks or fractures due to the external force received. Specifically, it is preferable that the length of the second end face 23b and the length of the third end face 23c are approximately the same.

[0039] As shown in FIG. 2, the piezoelectric element unit laminate 1006 includes two piezoelectric element units 6. The two piezoelectric element units 6 are laminated such that the respective piezoelectric elements 40 face each other. The two piezoelectric element units 6 are adhered by an adhesive 5. A substrate wiring 4a is formed on the circuit board 4. The circuit board 4 is disposed along the third end face 23c of the piezoelectric element unit 6, and the substrate wiring 4a is electrically connected to the wiring layer 70 via a bonding agent 8.

[0040] Since the protruding portion 24 is formed at the end portion 23, the contact area with the bonding agent 8 can be increased as compared with the case where the protruding portion 24 is not formed. Therefore, the bonding force between the piezoelectric element unit 6 and the circuit board 4 can be improved. Further, as shown by "S5" in FIG. 4, the second end face 23b is curved so as to be recessed in the Z direction. Therefore, when an external force is applied to the circuit board 4 shown in FIG. 2 in a direction away from the piezoelectric element unit 6, the curved second end face 23b serves as a resistance to the external force. Therefore, it is possible to make it difficult for the circuit board 4 to be peeled off from the piezoelectric element unit 6.

[0041] According to the first embodiment described above, the piezoelectric element unit 6 includes a semiconductor substrate 20, a piezoelectric element 40, a first insulating film 50, and a wiring layer 70. The semiconductor substrate 20 has a first main surface 21, a second main surface 22, and an end portion 23. The first insulating film 50 has a first insulating film end region 50a formed on the end portion 23. The wiring layer 70 has a wiring layer end region 70a formed on the first insulating film end region 50a. Since the wiring layer end region 70a is formed on the first insulating film end region 50a, when the piezoelectric element units 6 are stacked, the wiring layer end region 70a and the circuit board 4 can be electrically connected. Therefore, when a plurality of piezoelectric element units 6 are stacked, each of the plurality of piezoelectric element units 6 can be electrically connected via the wiring layer end region 70a. Since the wiring layer end region 70a is formed in the wiring layer forming step S9, it is possible to suppress an increase in manufacturing cost and realize electrical connection with each of the plurality of piezoelectric element units 6. Further, a protruding portion 24 is formed on the end portion 23. Therefore, when the circuit board 4 is disposed on the end portion 23 and the end portion 23 and the circuit board 4 are joined using the joining agent 8, the joining agent 8 can be brought into close contact with the second end surface 23b and the first end surface 23a constituting the protruding portion 24. Since the contact area between the joining agent 8 and the end portion 23 can be increased to improve the adhesion strength, the circuit board 4 mounted on the piezoelectric element unit 6 can be made difficult to peel off.

[0042] Further, scallops are formed on the first end surface 23a. Therefore, the surface area of the first end surface 23a is increased, and the adhesion of the first insulating film 50, which is a layer formed on the first end surface 23a, can be improved. Further, the second end surface 23b is curved so as to draw a curve from the connecting portion 24d toward the third end surface 23c. Therefore, when an external force is applied to the circuit board 4 in a direction away from the end portion 23, the curved second end surface 23b resists the external force, so that the circuit board 4 can be made difficult to peel off.

[0043] Further, the piezoelectric element unit 6 includes a second insulating film 60 formed on the second main surface 22. The second insulating film 60 extends up to the wiring layer end region 70a and has a second insulating film end region 60a formed on the wiring layer end region 70a. Therefore, it is possible to make it difficult for current leakage to occur between the semiconductor substrate 20 and the wiring layer 70.

[0044] Further, the wiring layer end region 70a has a wiring end surface 70b. The wiring end surface 70b recedes from the second main surface 22 in the direction from the second main surface 22 toward the first main surface 21. Therefore, when the corner formed by the second main surface 22 and the end 23 of the semiconductor substrate 20 is damaged, it is possible to make it difficult for the wiring layer end region 70a to be exposed. Therefore, it is possible to make it difficult for current leakage to occur between the semiconductor substrate 20 and the wiring layer 70.

[0045] Also, the manufacturing method of the piezoelectric element unit 6 includes a preparation step S1, a first groove formation step S3, a second groove formation step S5, a first insulating film formation step S7, a wiring layer formation step S9, a support substrate adhesion step S13, a grinding step S15, an etching step S19, a second insulating film formation step S21, and an adhesive removal step S23. Thereby, it is possible to manufacture the piezoelectric element unit 6 having a first end surface 23a intersecting the first main surface 21 and a protruding portion 24 protruding outward from the first end surface 23a between the first end surface 23a and the second main surface 22.

[0046] B. Second Embodiment: B1. Schematic Configuration of Piezoelectric Driving Device: FIG. 7 is an explanatory diagram showing the configuration of the piezoelectric driving device 1 according to the second embodiment. FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 7. FIG. 9 is a plan view showing the schematic configuration of the piezoelectric element unit 206. The main difference between the piezoelectric element unit 206 of the present embodiment and the piezoelectric element unit 6 of the first embodiment is the planar shape viewed from the Z direction. The same components and the same steps as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions are omitted as appropriate.

[0047] As shown in Fig. 7, the piezoelectric drive device 1 includes a rotor 2 as a driven body and a vibration actuator 3. The rotor 2 has a disk shape with a central axis O and is rotatable about the central axis O. The piezoelectric drive device 1 rotates the rotor 2 around the central axis O by the vibration of the vibration actuator 3.

[0048] The vibration actuator 3 includes two piezoelectric element units 206, a first substrate 12, a second substrate 14, a contact portion 16, and a spacer 18. The two piezoelectric element units 206 are stacked to form a piezoelectric element unit stack 1206. The contact portion 16 is disposed at the tip of the piezoelectric element unit stack 1206 close to the rotor 2. The contact portion 16 is disposed at a position where it can contact the outer peripheral surface 2a of the rotor 2 when the piezoelectric element unit 206 is deformed.

[0049] As shown in Fig. 8, the first substrate 12 and the second substrate 14 are disposed to face each other in the Z direction with the piezoelectric element unit stack 1206 interposed therebetween. In the present embodiment, silicon substrates are used as the first substrate 12 and the second substrate 14. As shown in Fig. 7, the first substrate 12 includes a first substrate first portion 12a extending in the Y direction, a first substrate second portion 12b disposed side by side with the first substrate first portion 12a, and two leaf spring portions 12c. The leaf spring portions 12c are portions in which a plurality of generally Y-direction elongated portions connecting the first substrate first portion 12a and the first substrate second portion 12b are arranged in the X direction. The first substrate 12 and the second substrate 14 are attached such that the leaf spring portions 12c generate a biasing force in the direction in which the contact portion 16 is pressed against the rotor 2. Two through holes 12d penetrating in the thickness direction are formed in the first substrate first portion 12a. The second substrate 14 has the same shape as the first substrate 12.

[0050] The shape of the piezoelectric element unit 206 as viewed in plan from the Z direction substantially coincides with the outer shape of the semiconductor substrate 220 included in the piezoelectric element unit 206. As shown in FIG. 9, the semiconductor substrate 220 includes a U-shaped first semiconductor substrate portion 220a, a second semiconductor substrate portion 220b, and two connection portions 220c. The second semiconductor substrate portion 220b is disposed inside the first semiconductor substrate portion 220a. The two connection portions 220c are disposed to face each other in the Y direction with the second semiconductor substrate portion 220b interposed therebetween. The connection portion 220c connects the first semiconductor substrate portion 220a and the second semiconductor substrate portion 220b.

[0051] Here, among the piezoelectric element unit 206, the laminated structure formed on the second semiconductor substrate portion 220b is referred to as a vibrating portion 19. The vibrating portion 19 includes a plurality of piezoelectric elements 40 and vibrates when an alternating voltage is applied to the plurality of piezoelectric elements 40.

[0052] As shown in FIG. 7, the shape of the spacer 18 as viewed in plan is substantially the same as the shape of the first substrate portion 12a of the first substrate 12 as viewed in plan. As shown in FIG. 8, the spacer 18 has substantially the same thickness as the piezoelectric element unit laminate 1206. A through hole penetrating in the thickness direction is formed in the spacer 18 at a position overlapping the through hole 12d of the first substrate 12.

[0053] The spacer 18 is disposed so as to overlap the first substrate portion 12a of the first substrate 12 in the Z direction. The piezoelectric element unit laminate 1206 is disposed so as to overlap the second substrate portion 12b of the first substrate 12 in the Z direction. With the first substrate 12 and the second substrate 14 facing each other in the Z direction with the piezoelectric element unit laminate 1206 and the spacer 18 interposed therebetween, a fastening member (not shown) is inserted through the through hole 12d, and the vibration actuator 3 is fixed to a housing (not shown).

[0054] As shown in FIG. 9, seven piezoelectric element structures 240 are formed in the second semiconductor substrate portion 220b of the semiconductor substrate 220. The piezoelectric element structure 240 is configured by laminating two piezoelectric elements 40. Here, in order to distinguish the seven piezoelectric element structures 240, each of the seven piezoelectric element structures 240 is referred to as a piezoelectric element structure 240A, a piezoelectric element structure 240B, a piezoelectric element structure 240C, a piezoelectric element structure 240D, a piezoelectric element structure 240E, a piezoelectric element structure 240F, and a piezoelectric element structure 240G. When the seven piezoelectric element structures 240 are not distinguished, they are simply referred to as piezoelectric element structures 240. The piezoelectric element structures 240A to 240F are used to deform the vibrating portion 19. The piezoelectric element structure 240G is used to detect the degree of deformation of the vibrating portion 19.

[0055] The piezoelectric element structures 240A to 240F are arranged in a matrix. Specifically, the piezoelectric element structure 240A, the piezoelectric element structure 240C, and the piezoelectric element structure 240E are arranged at substantially equal intervals along the Y direction in this order. The piezoelectric element structure 240B, the piezoelectric element structure 240D, and the piezoelectric element structure 240F are arranged at substantially equal intervals along the Y direction in this order. The piezoelectric element structure 240A and the piezoelectric element structure 240B are arranged along the X direction. The piezoelectric element structure 240C and the piezoelectric element structure 240D are arranged along the X direction. The piezoelectric element structure 240E and the piezoelectric element structure 240F are arranged along the X direction. The piezoelectric element structure 240G is arranged between the piezoelectric element structure 240C and the piezoelectric element structure 240D.

[0056] The piezoelectric element structure 240G is arranged substantially at the center of the piezoelectric body arrangement range Rp that includes and contacts the piezoelectric element structures 240A to 240F. Further, the piezoelectric element structure 240G is arranged such that its position in the X direction coincides with the position of the connection portion 220c in the X direction.

[0057] FIG. 10 is a plan view showing the pattern of the wiring layer 70 in the present embodiment. In FIG. 10, for convenience, the pattern of the wiring layer 70 is shown hatched. The wiring layer 70 is processed in the manufacturing process so that seven wirings from wiring 270A to wiring 270G are formed. Wiring 270A is electrically connected to a second electrode 92 (to be described later) of the piezoelectric element structure 240E. Wiring 270B is electrically connected to the second electrode 92 of the piezoelectric element structure 240G. Wiring 270C is electrically connected to the second electrode 92 of the piezoelectric element structure 240F. Wiring 270D is electrically connected to a first electrode 91 (to be described later) of the piezoelectric element structure 240. Wiring 270E is electrically connected to the second electrode 92 of the piezoelectric element structure 240B. Wiring 270F is electrically connected to the second electrode 92 of the piezoelectric element structure 240C and the second electrode 92 of the piezoelectric element structure 240D. Wiring 270G is electrically connected to the second electrode 92 of the piezoelectric element structure 240A. The wirings 270A to 270G are electrically connected to the first electrode 91 or the second electrode 92 through contact holes formed in the first insulating film 50.

[0058] The wirings 270A to 270G are routed to the -X-axis direction ends of the connection portion 220c and the first part 220a of the semiconductor substrate.

[0059] B2. Cross-sectional structure of the piezoelectric element unit: FIG. 11 is a cross-sectional view taken along line XI-XI of FIG. 9. FIG. 12 is a cross-sectional view taken along line XII-XII of FIG. 10. FIG. 13 is a cross-sectional view taken along line XIII-XIIII of FIG. 9.

[0060] As shown in FIG. 11, the piezoelectric element unit laminate 1206 includes two stacked piezoelectric element units 206. Similar to the first embodiment, a piezoelectric element 40 having a first electrode layer 41, a piezoelectric layer 42, and a second electrode layer 43 is formed on the semiconductor substrate 220 of the piezoelectric element unit 206. A first insulating film 50 is formed on the piezoelectric element 40. The two piezoelectric element units 206 are stacked such that their respective first insulating films 50 face each other. The two piezoelectric element units 206 are adhered by an adhesive 5.

[0061] As shown in FIG. 9, the shape of the first electrode layer 41 in plan view is generally rectangular and covers the piezoelectric body arrangement range Rp.

[0062] The second electrode layer 43 is formed separately in the regions of each of the seven piezoelectric element structures 240 from the piezoelectric element structure 240A to the piezoelectric element structure 240G.

[0063] Note that the piezoelectric element 40 is a region where the first electrode layer 41, the piezoelectric body layer 42, and the second electrode layer 43 overlap in plan view. Here, the region of the first electrode layer 41 that constitutes the piezoelectric element 40 is referred to as the first electrode 91. The region of the second electrode layer 43 that constitutes the piezoelectric element 40 is referred to as the second electrode 92.

[0064] As shown in FIGS. 12 and 13, the wiring layer 70 is formed on the first insulating film 50. As shown in FIG. 13, also in this embodiment, the end portion 23 includes a first end face 23a and a protruding portion 24. Since the layer structure of the piezoelectric element unit 206 is the same as the layer structure of the piezoelectric element unit 6 of the first embodiment, a detailed description thereof will be omitted.

[0065] Note that, as shown in FIG. 13, a piezoelectric element structure 45 having the same layer structure as the piezoelectric element 40 is formed in the first part 220a of the semiconductor substrate. The piezoelectric element structure 45 is configured by laminating a first electrode layer 41, a piezoelectric body layer 42, and a second electrode layer 43 in this order. However, unlike the piezoelectric element 40, it does not contribute to the deformation of the piezoelectric element unit 206. Specifically, a voltage is not applied between the first electrode layer 41 of the piezoelectric element structure 45 and the second electrode layer 43 of the piezoelectric element structure 45. By forming the piezoelectric element structure 45, the distance between the two semiconductor substrates 220 arranged to face each other can be made equal to that of the second part 220b of the semiconductor substrate. Thereby, the structure of the piezoelectric element unit laminate 1206 can be stabilized.

[0066] B3. Manufacturing Method of Vibration Actuator FIG. 14 is a flowchart of a manufacturing process for realizing a method of manufacturing the vibration actuator 3. In the manufacturing process S31 of the piezoelectric unit in FIG. 14, the piezoelectric element unit 206 is manufactured. Since the manufacturing process S31 of the piezoelectric element unit is the same as the manufacturing process of the piezoelectric element unit in the first embodiment shown in FIG. 3, the description thereof is omitted.

[0067] In the lamination process S33 of FIG. 14, two piezoelectric element units 206 are laminated. The two piezoelectric element units 206 are laminated such that the respective piezoelectric elements 40 face each other. The two piezoelectric element units 206 are adhered by an adhesive 5. Since the upper insulating film 80 is formed on the wiring layer 70, even when a gap is formed in the adhesive 5, it is possible to suppress current leakage between any two of the wirings from the wiring 270A to the wiring 270F.

[0068] In the circuit board bonding process S35, the circuit board 4 is bonded to the two laminated piezoelectric element units 206. In the present embodiment, the circuit board 4 shown in FIG. 13 is an FPC (Flexible Printed Circuits). A board wiring 4a is formed on the circuit board 4. The circuit board 4 is arranged along the end portion 23 of the piezoelectric element unit 6, and the two laminated piezoelectric element units 206 and the circuit board 4 are bonded by a bonding agent 8. Thereby, the board wiring 4a is electrically connected to the exposed wiring layer end region 70a of the wiring layer 70. As the bonding agent 8, a conductive metal such as solder, brazing material, or metal paste, an anisotropic conductive material such as anisotropic conductive paste or anisotropic conductive sheet can be used. Among these, the bonding agent 8 is preferably a conductive metal or an anisotropic conductive material because it enables efficient electrical connection at a relatively low temperature and has a small contact resistance. Similar to the first embodiment, since the protruding portion 24 is formed at the end portion 23 of the semiconductor substrate 220, the surface area of the end portion 23 functioning as the bonding surface can be increased. Therefore, the circuit board 4 can be made difficult to peel off.

[0069] B4. Driving method of the piezoelectric driving device: FIG. 15 is an explanatory diagram showing the electrical configuration of the vibration actuator 3. FIG. 16 is a diagram showing the waveforms of the drive signal and the detection signal input to the piezoelectric element unit 206. The vibration actuator 3 further includes a control unit 7. The control unit 7 uses the circuit board 4 to input drive signals Sig1 to Sig3 to the piezoelectric element unit 206. Also, a detection signal Sigd output from the piezoelectric element structure 240G is input to the control unit 7.

[0070] The control unit 7 is configured as a computer including a processor and a memory. Note that the control unit 7 may be configured by a dedicated circuit such as an ASIC (Application Specific Integrated Circuit).

[0071] As described above, a ground voltage, which is a common voltage, is applied to each first electrode 91 of the piezoelectric element structures 240A to 240G. The drive signal Sig1 is applied to each second electrode layer 43 of the piezoelectric element structures 240A and 240F. The drive signal Sig2 is applied to each second electrode layer 43 of the piezoelectric element structures 240C and 240D. The drive signal Sig3 is applied to each second electrode layer 43 of the piezoelectric element structures 240E and 240B.

[0072] As shown in FIG. 16, the drive signals Sig1 to Sig3 are AC voltages having the same frequency as each other. The drive signal Sig1 is shifted by 1 / 2π, which is a desired phase difference determined by the drive conditions, with respect to the drive signal Sig2. The drive signal Sig3 is phase-shifted by π with respect to the drive signal Sig1.

[0073] FIG. 17 is a diagram for explaining the deformation state of the piezoelectric element unit 206. When drive signals Sig1 to Sig3 are input to the piezoelectric element unit 206, the piezoelectric element unit 206 expands and contracts in the X direction and bends in an S shape in the Y direction while vibrating. Then, the contact portion 16 makes an elliptical motion that rotates counterclockwise along an elliptical orbit as indicated by arrow A1. As a result, the rotor 2 rotates in the direction of arrow B1. Note that a gap is formed between the second semiconductor substrate portion 220b in which the vibrating portion 19 is formed and the first semiconductor substrate portion 220a. Therefore, even when the second semiconductor substrate portion 220b is deformed, contact between the first semiconductor substrate portion 220a and the second semiconductor substrate portion 220b is prevented.

[0074] In the elliptical motion of the contact portion 16 indicated by arrow A1, from point A1a to point A1b, the contact portion 16 abuts on the outer peripheral surface 2a of the rotor 2 and sends the rotor 2 in the direction of arrow B1, and from point A1b to point A1a, the contact portion 16 is separated from the outer peripheral surface 2a of the rotor 2. Therefore, from point A1b to point A1a, rotation of the rotor 2 in the direction opposite to arrow B1 is suppressed.

[0075] In contrast to the above, when the drive signal Sig3 is input to the second electrodes 92 of the piezoelectric element structures 240A and 240F, and the drive signal Sig1 is input to the second electrodes 92 of the piezoelectric element structures 240E and 240B, the contact portion 16 performs an elliptical motion that rotates the rotor 2 in the direction of arrow B2 shown in FIG. 7.

[0076] The control unit 7 adjusts the drive signals Sig1 to Sig3 using the detection signal Sigd output from the piezoelectric element structure 240G. Since the piezoelectric element structure 240G is the piezoelectric element 40, a voltage is output due to the deformation of the piezoelectric element structure 240G. That is, the piezoelectric element structure 240G outputs a detection signal Sigd that reflects the vibration of the vibrating portion 19. As described above, since the piezoelectric element structure 240G is arranged at the center of the piezoelectric body arrangement range Rp, the piezoelectric element structure 240G mainly outputs a detection signal Sigd that reflects the expansion and contraction vibration in the X direction.

[0077] According to the second embodiment described above, the same effects as those of the first embodiment are achieved. That is, a protruding portion 24 is formed at the end portion 23 of the piezoelectric element unit 206. Therefore, when the circuit board 4 is disposed at the end portion 23 and the end portion 23 and the circuit board 4 are joined using the bonding agent 8, the contact area between the bonding agent 8 and the end portion 23 can be increased, and the adhesion strength can be improved. Therefore, the circuit board 4 mounted on the piezoelectric element unit 206 can be made difficult to peel off. Further, since scallops are formed on the first end surface 23a, the bonding force with the first insulating film 50 formed on the first end surface 23a can be improved. Further, since the second end surface 23b is curved so as to draw a curve from the connection portion 24d toward the third end surface 23c, when the circuit board 4 is mounted on the end portion 23, the circuit board 4 can be made difficult to peel off. Further, since the second insulating film 60 has the second insulating film end region 60a formed on the wiring layer end region 70a, current leakage between the semiconductor substrate 1020 and the wiring layer 70 can be made difficult to occur. Further, since the wiring end surface 70b recedes from the second main surface 22, even when the corner of the semiconductor substrate 220 is damaged, current leakage between the semiconductor substrate 220 and the wiring layer 70 can be made difficult to occur.

[0078] Further, the piezoelectric driving device 1 includes a piezoelectric element unit 206, a contact portion 16, and a rotor 2. Therefore, it is possible to provide the piezoelectric driving device 1 using the piezoelectric element unit 206 in which an increase in manufacturing cost is suppressed. Further, the piezoelectric driving device 1 includes a plurality of stacked piezoelectric element units 206. Therefore, it is possible to provide the piezoelectric driving device 1 having a higher output than the case where one piezoelectric element unit 206 is provided.

[0079] Also, as shown in FIG. 13, when one of the two piezoelectric element units 206 is referred to as the first piezoelectric element unit 206 and the other piezoelectric element unit 206 is referred to as the second piezoelectric element unit 206, the piezoelectric element 40 of the first piezoelectric element unit 206 faces the piezoelectric element 40 of the second piezoelectric element unit 206. Thereby, the protruding portion 24 can form a recessed portion recessed with respect to the third end face 23c. Therefore, when the bonding agent 8 is supplied, it is possible to easily hold the bonding agent at the end portion 23 of the plurality of stacked piezoelectric element units 206. Therefore, an electrical connection can be made well between the plurality of piezoelectric element units 206 and the circuit board 4.

[0080] Also, the circuit board 4 is arranged along the end portion 23, and the board wiring 4a is electrically connected to the wiring layer 70. Thereby, a drive signal can be input to the piezoelectric element unit 206 using the circuit board 4.

[0081] C. Third Embodiment: FIG. 18 is an explanatory diagram showing a robot 3000 according to the third embodiment. The robot 3000 shown in FIG. 18 can perform operations such as feeding, removing, transporting, and assembling precision instruments and components constituting the same. The robot 3000 includes a control unit (not shown). The control unit is configured as a computer including a processor and a memory. The operations of the joints 3130 and the like, which will be described later, of the robot 3000 are controlled by the control unit.

[0082] The robot 3000 is a six-axis robot and includes a base 3110 fixed to the floor or ceiling, a plurality of arms 3120 rotatably connected to the base 3110, and a plurality of joints 3130. A piezoelectric drive device 1 is mounted as a power source on some or all of the joints 3130, and the target arm 3120 rotates by driving the piezoelectric drive device 1.

[0083] A hand connection part is provided on the tip arm 3120, and a moving stage 3200 is mounted on the hand connection part. The moving stage 3200 includes a base 3210 connected to the hand connection part, a first stage 3220, a second stage 3230, a first stage moving mechanism 3240, and a second stage moving mechanism 3250. The first stage 3220 moves in a first direction U with respect to the base 3210. The second stage 3230 moves in a second direction V orthogonal to the first direction U with respect to the first stage 3220. The first stage moving mechanism 3240 moves the first stage 3220 in the first direction U with respect to the base 3210. The second stage moving mechanism 3250 moves the second stage 3230 in the second direction V with respect to the first stage 3220.

[0084] One or both of the first stage moving mechanism 3240 and the second stage moving mechanism 3250 are equipped with a piezoelectric driving device 1 as its power source, and the target first stage 3220 or second stage 3230 is moved by driving the piezoelectric driving device 1.

[0085] Also, an inkjet head 3300 is mounted on the second stage 3230. The robot 3000 performs a printing operation on the object Q by discharging ink from the inkjet head 3300. As described above, the moving stage 3200 is interposed between the robot 3000 and the inkjet head 3300. Therefore, for example, the inkjet head 3300 can be moved by the moving stage 3200 with the robot 3000 stopped. Thereby, a stable printing operation can be performed.

[0086] As described above, the moving stage 3200 of the present embodiment includes a base 3210, a first stage 3220 and a second stage 3230 as stages that move with respect to the base 3210, and a piezoelectric driving device 1.

[0087] According to the third embodiment described above, it is possible to provide a moving stage 3200 and a robot 3000 including a piezoelectric driving device 1 including a piezoelectric element unit 206 in which an increase in manufacturing cost is suppressed.

[0088] D. Other Embodiments: (D1) FIG. 19 is a diagram for explaining another embodiment of the piezoelectric driving device 1. In the piezoelectric driving device 1 of the second embodiment, two piezoelectric element units 206 are stacked. In contrast, the piezoelectric driving device according to another embodiment shown in FIG. 19 is configured by further stacking a plurality of two stacked piezoelectric element units 206. By increasing the number of piezoelectric element units 206, the output of the piezoelectric driving device can be increased. When the number of piezoelectric element units 206 is 8 or more, it is preferable because deformation of the piezoelectric element unit 206 can be suppressed and unnecessary vibration can be suppressed.

[0089] (D2) At the end 23 of the semiconductor substrate 220 of the piezoelectric element unit 206 of the first embodiment, one protruding portion 24 is formed. The number of protruding portions 24 is not limited to 1, and two or more protruding portions 24 may be formed. That is, the end 23 may further include a protruding portion protruding outward from the third end face 23c.

[0090] (D3) The second end face 23b of the piezoelectric element unit 6 of the first embodiment is curved so as to be recessed in the Z direction. As another embodiment, the second end face 23b may be curved so as to protrude in the Z direction. Regardless of its shape, the second end face 23b can resist an external force applied in a direction away from the end 23 to the mounted circuit board 4 by being curved.

[0091] (D4) In the second embodiment described above, the piezoelectric drive device 1 has one vibration actuator 3. As another embodiment, the piezoelectric drive device 1 may have a plurality of vibration actuators 3 arranged at intervals in the circumferential direction of the rotor 2. Further, the vibration actuator 3 may be in contact with a surface orthogonal to the central axis O of the rotor 2 instead of the outer peripheral surface 2a of the rotor 2. Further, the driven body is not limited to a rotating body such as the rotor 2, and may be, for example, a slider that moves linearly.

[0092] (D5) The device mounted on the second stage 3230 of the robot 3000 in the third embodiment described above is the inkjet head 3300, but it is not limited thereto. Other end effectors can be mounted on the second stage 3230 according to the work content of the robot. Further, in the third embodiment described above, the piezoelectric drive device 1 is applied to the robot 3000. The application examples of the piezoelectric drive device 1 are not limited to robots. For example, it can be applied to the drive mechanism of a paper feed roller of a printing device.

[0093] E. Other forms: The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the gist thereof. For example, the technical features of the embodiments corresponding to the technical features in each of the forms described below can be appropriately replaced or combined in order to solve some or all of the above-described problems or to achieve some or all of the above-described effects. Further, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

[0094] (1) According to the first aspect of the present disclosure, a piezoelectric element unit is provided. This piezoelectric element unit includes a semiconductor substrate having a first main surface, a second main surface located on the opposite side of the first main surface, and an end portion connecting the first main surface and the second main surface, a piezoelectric element formed on the first main surface, a first insulating film formed on the piezoelectric element and extending up to the end portion, a wiring layer formed on the first insulating film and electrically connected to the piezoelectric element, and a second insulating film formed on the second main surface. The first insulating film has a first insulating film end region formed on the end portion, the wiring layer extends up to the first insulating film end region and has a wiring layer end region formed on the first insulating film end region. The end portion has an end surface intersecting the first main surface and a protruding portion protruding outward from the end surface between the end surface and the second main surface. According to this aspect, since the wiring layer end region is formed on the first insulating film end region, when piezoelectric element units are stacked, the wiring layer end region can be electrically connected to a circuit board. Therefore, when a plurality of piezoelectric element units are stacked, each of the plurality of piezoelectric element units can be electrically connected via the wiring layer end region. Since the wiring layer end region is formed in the wiring layer forming process, an increase in manufacturing cost can be suppressed and electrical connection with each of the plurality of piezoelectric element units can be realized. Further, a protruding portion is formed at the end portion. Therefore, when a circuit board is disposed at the end portion and the end portion and the circuit board are joined using an adhesive, the adhesive can be brought into close contact with the surface constituting the protruding portion and the end surface. Since the contact area between the adhesive and the end portion can be increased and the adhesion strength can be improved, the circuit board mounted on the piezoelectric element unit can be made difficult to peel off.

[0095] (2) In the piezoelectric element unit of the above aspect, scallops in which uneven structures are arranged in the direction from the first main surface toward the second main surface may be formed on the end surface. According to this aspect, the scallops can increase the contact area between the first insulating film formed on the end surface and the end surface, so that the bonding strength between the end surface and the first insulating film can be improved.

[0096] (3) In the piezoelectric element unit of the above-described embodiment, the protruding portion may have an upper surface connecting the end surface and the tip of the protruding portion, and the upper surface may be curved so as to draw a curve from the connection portion between the end surface and the protruding portion toward the tip. According to this embodiment, when a circuit board is mounted on the end portion, even when an external force is applied to the circuit board in a direction away from the end portion, the curved upper surface resists the external force, so that the circuit board can be made difficult to peel off.

[0097] (4) According to the second embodiment of the present disclosure, a piezoelectric driving device is provided. This piezoelectric driving device may include a contact portion that performs elliptical motion due to the vibration of the piezoelectric element, and a driven body that is driven by the contact portion. According to this embodiment, it is possible to provide a piezoelectric driving device using a piezoelectric element unit in which an increase in manufacturing cost is suppressed.

[0098] (5) In the piezoelectric driving device of the above-described embodiment, the second insulating film may extend up to the wiring layer end region and may have a second insulating film end region formed on the wiring layer end region. According to this embodiment, the end of the wiring layer end region in the direction from the first main surface to the second main surface can be covered with the second insulating film. Therefore, it is possible to make it difficult for leakage to occur between the semiconductor substrate and the wiring layer.

[0099] (6) In the piezoelectric driving device of the above-described embodiment, the wiring layer end region has a wiring end surface that is an end surface in the direction from the first main surface to the second main surface, and the wiring end surface may recede from the second main surface in the direction from the second main surface to the first main surface. According to this embodiment, when the corner formed by the second main surface and the end portion of the semiconductor substrate is damaged, it is possible to make it difficult to expose the wiring layer end region. Therefore, it is possible to make it difficult for leakage to occur between the semiconductor substrate and the wiring layer.

[0100] (7) In the piezoelectric driving device of the above-described embodiment, a plurality of the piezoelectric element units may be provided, and the plurality of piezoelectric element units may be stacked. According to this embodiment, it is possible to provide a piezoelectric driving device with a higher output than in the case of providing one piezoelectric element unit.

[0101] (8) In the piezoelectric drive device of the above-described embodiment, the plurality of piezoelectric element units include a first piezoelectric element unit and a second piezoelectric element unit laminated on the first piezoelectric element unit, and the piezoelectric element of the first piezoelectric element unit may face the piezoelectric element of the second piezoelectric element unit. According to this embodiment, a recessed portion that is recessed with respect to each end face of the first piezoelectric element unit and the second piezoelectric element unit can be formed by the protruding portion of the first piezoelectric element unit and the protruding portion of the second piezoelectric element unit. Therefore, when the bonding agent is supplied, it is possible to easily hold the bonding agent at the end portions of the plurality of laminated piezoelectric element units. Therefore, an electrical connection can be satisfactorily made between the plurality of piezoelectric element units and the circuit board.

[0102] (9) The piezoelectric drive device of the above-described embodiment further includes a circuit board on which substrate wiring is formed, the circuit board is arranged along the end portion, and the substrate wiring may be electrically connected to the wiring layer. According to this embodiment, a drive signal can be input to the piezoelectric element unit using the circuit board.

[0103] (10) According to the first aspect of the present disclosure, a method for manufacturing a piezoelectric element unit is provided. A preparation step of preparing a laminate including a semiconductor substrate having a first main surface, a second main surface located on the side opposite to the first main surface, and an end portion connecting the first main surface and the second main surface, and a piezoelectric element formed on the first main surface; a first groove forming step of forming a first groove on the first main surface of the semiconductor substrate; a second groove forming step of forming a second groove on the bottom surface of the first groove; a first insulating film forming step of forming a first insulating film covering the piezoelectric element, a first exposed surface of the first groove, and a second exposed surface of the second groove; a wiring layer forming step of forming a wiring layer covering the first insulating film; a support substrate adhesion step of disposing a support substrate so as to face the first main surface and adhering the laminate and the support substrate via an adhesive; a grinding step of grinding the second main surface to penetrate the second groove; an etching step of etching the second main surface as a processing surface to retreat a wiring end surface of the wiring layer exposed on the second main surface side by the grinding step; a second insulating film forming step of forming a second insulating film so as to cover the second main surface and the wiring end surface; and an adhesive removing step of removing the adhesive may be provided. According to this aspect, a piezoelectric element unit having, at an end portion, an end surface intersecting the first main surface and, between the end surface and the second main surface, a protruding portion protruding outward from the end surface can be manufactured.

Description of Reference Numerals

[0104] 1…Piezoelectric drive device, 2…Rotator, 2a…Outer peripheral surface, 3…Vibration actuator, 4…Circuit board, 4a…Board wiring, 5…Adhesive, 6,206…Piezoelectric element unit, 7…Control unit, 8…Bonding agent, 12…First substrate, 12a…First part of the first substrate, 12b…Second part of the first substrate, 12c…Leaf spring part, 12d…Through hole, 14…Second substrate, 16…Contact part, 18…Intermediate seat, 19…Vibration part, 20,220,1020…Semiconductor substrate, 21…First main surface, 22…Second main surface, 23…End part, 23a…First end face, 23b…Second end face, 23c…Third end face, 24…Protrusion, 24d…Connection part, 25…First groove, 26…Second groove, 40…Piezoelectric element, 41…First electrode layer, 42…Piezoelectric body layer, 43…Second electrode layer, 45…Piezoelectric element structure, 50…First insulating film, 50a…End region of the first insulating film, 60…Second insulating film, 60a…End region of the second insulating film, 70…Wiring layer, 70a…End region of the wiring layer, 70b…Wiring end face, 80…Upper insulating film, 91…First electrode, 92…Second electrode, 220a…First part of the semiconductor substrate, 220b…Second part of the semiconductor substrate, 220c…Connection part, 240,240A~240G…Piezoelectric element structure body, 270A~270G…Wiring, 1000…Laminate, 1006,1206…Piezoelectric element unit laminate, 1030…Adhesive, 1040…Support substrate, 3000…Robot, 3110…Base, 3120…Arm, 3130…Joint, 3200…Moving stage, 3210…Base part, 3220…First stage, 3230…Second stage, 3240…First stage moving mechanism, 3250…Second stage moving mechanism, 3300…Inkjet head, Q…Object, Rp…Piezoelectric body arrangement range, Sig1~Sig3…Drive signal, Sigd…Detection signal

Claims

1. A piezoelectric element unit, comprising: a semiconductor substrate having a first main surface, a second main surface located on the side opposite to the first main surface, and an end portion connecting the first main surface and the second main surface; a piezoelectric element formed on the first main surface; a first insulating film formed on the piezoelectric element and extending up to the end portion, the first insulating film; a wiring layer formed on the first insulating film and electrically connected to the piezoelectric element; a second insulating film formed on the second main surface; the first insulating film having a first insulating film end region formed on the end portion; the wiring layer extending up to the first insulating film end region and having a wiring layer end region formed on the first insulating film end region; the end portion having an end surface intersecting the first main surface and a protruding portion protruding outward from the end surface between the end surface and the second main surface, the piezoelectric element unit.

2. The piezoelectric element unit according to claim 1, wherein scallops in which an uneven structure is arranged in a direction from the first main surface toward the second main surface are formed on the end surface, the piezoelectric element unit.

3. The piezoelectric element unit according to claim 1 or 2, wherein the protruding portion has an upper surface connecting the end surface and a tip of the protruding portion, and the upper surface is curved so as to draw a curve from a connection portion between the end surface and the protruding portion toward the tip, the piezoelectric element unit.

4. The piezoelectric element unit according to claim 1, a contact portion that performs elliptical motion due to vibration of the piezoelectric element, and a driven body driven by the contact portion, the piezoelectric driving device.

5. The piezoelectric driving device according to claim 4, wherein the second insulating film extends up to the wiring layer end region and has a second insulating film end region formed on the wiring layer end region, the piezoelectric driving device.

6. The piezoelectric driving device according to claim 5, wherein the wiring layer end region has a wiring end surface that is an end surface in a direction from the first main surface toward the second main surface, and the wiring end surface retreats from the second main surface in a direction from the second main surface toward the first main surface, the piezoelectric driving device.

7. The piezoelectric driving device according to any one of claims 4 to 6, wherein a plurality of the piezoelectric element units are provided, and the plurality of piezoelectric element units are stacked, the piezoelectric driving device.

8. The piezoelectric driving device according to claim 7, The plurality of piezoelectric element units include a first piezoelectric element unit and a second piezoelectric element unit laminated on the first piezoelectric element unit. The piezoelectric element of the first piezoelectric element unit faces the piezoelectric element of the second piezoelectric element unit, which is a piezoelectric driving device.

9. A piezoelectric driving device according to claim 4, further comprising a circuit board on which a board wiring is formed, wherein the circuit board is arranged along the end portion, and the board wiring is electrically connected to the wiring layer, which is a piezoelectric driving device.

10. A preparation step of preparing a laminate including a semiconductor substrate having a first main surface, a second main surface located on the opposite side of the first main surface, and an end portion connecting the first main surface and the second main surface, and a piezoelectric element formed on the first main surface; a first groove forming step of forming a first groove in the first main surface of the semiconductor substrate; a second groove forming step of forming a second groove in the bottom surface of the first groove; a first insulating film forming step of forming a first insulating film covering the piezoelectric element, a first exposed surface of the first groove, and a second exposed surface of the second groove; a wiring layer forming step of forming a wiring layer covering the first insulating film; a support substrate adhesion step of arranging a support substrate so as to face the first main surface and adhering the laminate and the support substrate via an adhesive; a grinding step of grinding the second main surface to penetrate the second groove; an etching step of etching the second main surface as a processing surface to retreat a wiring end surface of the wiring layer exposed on the second main surface side by the grinding step; a second insulating film forming step of forming a second insulating film so as to cover the second main surface and the wiring end surface; and an adhesive removing step of removing the adhesive, which is a method for manufacturing a piezoelectric element unit.

Images