Electronic devices

Abstract

The present invention provides an electronic device in which, during the manufacturing process of the through electrode, the through hole of the sealing plate is less likely to shrink and cause cracks in the vibrating plate. The electronic device (1) comprises: a first substrate (4) including a first surface (4a), an element (7) disposed on the first surface (4a), and a common terminal (11) connected to the element (7) disposed on the first surface (4a); and a second substrate (3) having a second surface (3a) and a third surface (3b), the second surface (3a) being disposed opposite to the first surface (4a), the second substrate (3) having a first through hole (13) at a position corresponding to the common terminal (11) extending from the second surface (3a) to the third surface (3b), a first through electrode (15) communicating with the common terminal (11) being disposed in the first through hole (13), and a gap (33) being provided in a portion of the first through electrode (15).

Description

Technical Field

[0001] This invention relates to electronic devices. Background Technology

[0002] Previously, electronic devices that arranged piezoelectric elements in a matrix were known. For example, Patent Document 1 discloses an electronic device comprising: a sealing plate having an opening; a vibrating plate that closes the opening; and piezoelectric elements disposed on the vibrating plate, with the piezoelectric elements sandwiched between an upper electrode and a lower electrode.

[0003] Therefore, the vibrating plate and the sealing plate are arranged opposite each other. The sealing plate restricts the range of vibration of the vibrating plate. The frequency of vibration of the vibrating plate is set according to the size of the vibrating plate surrounded by the opening of the sealing plate. The sealing plate is made of a brittle material that does not easily absorb the vibration of the vibrating plate.

[0004] A pair of through electrodes are disposed on a sealing plate. The upper and lower electrodes are respectively connected to the through electrodes. The sealing plate is disposed opposite to a wiring substrate. The wiring substrate has pads. The through electrodes protrude towards the wiring substrate. The pads are in electrical contact with the through electrodes. The upper and lower electrodes are respectively connected to the pads via the through electrodes.

[0005] The through-hole electrode is constructed from a resin-based adhesive containing metal filler. During the formation of the through-hole electrode, a liquid resin-based adhesive containing metal filler is introduced into the through-hole. The liquid resin-based adhesive is heated and dried to solidify. During this process, the solvent contained in the liquid resin-based adhesive evaporates. The resin-based adhesive shrinks in volume during the curing process.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-106183

[0007] Regarding the electronic device in Patent Document 1, during the manufacturing process of the through electrode, there is a potential risk that the through hole of the sealing plate will shrink and cause cracks on the vibration plate when the through electrode shrinks. Summary of the Invention

[0008] The electronic device comprises: a first substrate including a first surface, an element disposed on the first surface, and a first electrode connected to the element disposed on the first surface; and a second substrate having a second surface and a third surface, the second surface being disposed opposite to the first surface, the second substrate having a through hole at a position corresponding to the first electrode extending from the second surface to the third surface, a through electrode communicating with the first electrode being disposed in the through hole, and a gap being disposed in a portion of the through electrode. Attached Figure Description

[0009] Figure 1 This is a simplified exploded perspective view showing the configuration of the electronic devices in the first embodiment.

[0010] Figure 2 It is a schematic side sectional view showing the structure of an electronic device.

[0011] Figure 3 It is a schematic side sectional view showing the structure of an electronic device.

[0012] Figure 4 This is a schematic top view showing the structure of the first substrate.

[0013] Figure 5 This is a schematic side sectional view showing the configuration of the through electrode.

[0014] Figure 6 This is a schematic side sectional view used to illustrate the manufacturing method of the through electrode.

[0015] Figure 7 This is a schematic side sectional view used to illustrate the manufacturing method of the through electrode.

[0016] Figure 8 This is a schematic side sectional view used to illustrate the manufacturing method of the through electrode.

[0017] Figure 9 This is a schematic side sectional view used to illustrate the manufacturing method of the through electrode.

[0018] Figure 10 This is a schematic side sectional view used to illustrate the manufacturing method of the through electrode.

[0019] Figure 11 This is a schematic side sectional view used to illustrate the manufacturing method of the through electrode.

[0020] Figure 12 This is a schematic side sectional view used to illustrate the manufacturing method of the through electrode.

[0021] Figure 13 This is a diagram used to illustrate the relationship between the area ratio of the through electrode to the through hole and the resistance between terminals.

[0022] Explanation of reference numerals in the attached figures

[0023] 1. Electronic device; 2. Third substrate; 3. Second substrate; 3a. Second surface; 3b. Third surface; 4. First substrate; 4a. First surface; 6. First direction; 7. Component; 11. Common terminal as first electrode; 12. Driving terminal as first electrode; 13. First through hole as through hole; 14. Second through hole as through hole; 15. First through electrode as through electrode; 16. Second through electrode as through electrode; 21. Common connection terminal as second electrode; 22. Driving connection terminal as second electrode; 33. Gap; 36. Second direction. Detailed Implementation

[0024] First Implementation Method

[0025] In this embodiment, characteristic examples of an electronic device and an electronic device manufacturing method for manufacturing the electronic device will be described.

[0026] like Figure 1 As shown, in electronic device 1, the third substrate 2, the second substrate 3, the first substrate 4, and the fourth substrate 5 are stacked sequentially in the Z direction. In the Z direction, the side of the fourth substrate 5 is designated as the positive Z direction, and the side of the third substrate 2 is designated as the negative Z direction. The direction along the positive Z direction is designated as the first direction 6. The first direction 6 is the stacking direction of the first substrate 4 and the second substrate 3.

[0027] When viewed from the first direction 6, the third substrate 2, the second substrate 3, the first substrate 4, and the fourth substrate 5 are rectangular. The long sides of the third substrate 2, the second substrate 3, the first substrate 4, and the fourth substrate 5 are in the same direction. The second substrate 3, the first substrate 4, and the fourth substrate 5 are of the same shape. The third substrate 2 is larger than the second substrate 3, the first substrate 4, and the fourth substrate 5.

[0028] The long side direction of the third substrate 2 is defined as the X direction. The short side direction of the third substrate 2 is defined as the Y direction. The X, Y, and Z directions are orthogonal to each other.

[0029] The first substrate 4 includes a first surface 4a on the side facing the second substrate 3. Elements 7 are arranged in a matrix on the first surface 4a. The elements 7 are piezoelectric elements. According to this configuration, the elements 7 are piezoelectric elements. By applying an alternating voltage to the elements 7, the electronic device 1 can cause the first substrate 4 to vibrate and emit ultrasonic waves. The first substrate 4 is also referred to as a vibrating plate.

[0030] The number of elements 7 is not particularly limited. In this embodiment, for example, since the elements 7 are arranged in a 4x4 grid, the number of elements 7 is 16.

[0031] The fourth substrate 5 has four fourth holes 8 that extend in the X direction. When viewed from the first direction 6, the shape of the fourth hole 8 is a parallelogram. The fourth substrate 5 is formed from a single-crystal silicon substrate. The fourth holes 8 are formed by a wet etching method. The side surfaces of the fourth holes 8 become crystalline surfaces with slow etching rates. In a single-crystal silicon substrate, since crystalline surfaces with slow etching rates are parallelograms, the shape of the fourth hole 8 is a parallelogram. The fourth holes 8 penetrate the fourth substrate 5. The fourth holes 8 are disposed at locations opposite to the arrangement of the components 7. It should be noted that the number of fourth holes 8 is not limited to four.

[0032] The second substrate 3 has a second surface 3a and a third surface 3b. The second surface 3a is disposed opposite to the first surface 4a of the first substrate 4. The second substrate 3 has four second grooves 9 that are elongated in the Y direction on the second surface 3a. When viewed from the first direction 6, the shape of the second grooves 9 is a parallelogram. The second substrate 3 is formed from a silicon single crystal substrate. The second grooves 9 are formed by a wet etching method. Therefore, the shape of the second grooves 9 is a parallelogram. The second grooves 9 are disposed at the positions opposite to the arrangement of the components 7.

[0033] When viewed from the first direction 6, the element 7 is disposed at the location where the fourth hole 8 intersects with the second groove 9. Therefore, at the location where the element 7 is disposed, the first substrate 4 can vibrate in both the positive and negative Z directions.

[0034] The first substrate 4 and the fourth substrate 5 are integral. The first substrate 4 is made of silicon oxide and is formed by oxidizing the fourth substrate 5.

[0035] The first substrate 4 has a common terminal 11 serving as a first electrode and a drive terminal 12 serving as a first electrode on its first surface 4a. The common terminal 11 and the drive terminal 12 are electrically connected to the component 7.

[0036] The second substrate 3 has a first through hole 13, which extends from the second surface 3a to the third surface 3b, at a position corresponding to the common terminal 11. The second substrate 3 also has a second through hole 14, which extends from the second surface 3a to the third surface 3b, at a position corresponding to the drive terminal 12.

[0037] The size of the first through-hole 13 is not particularly limited. In this embodiment, for example, the length of the long side of the first through-hole 13 is approximately 1 mm. The width of the first through-hole 13 in the X direction is approximately 350 μm. The thickness of the second substrate 3 is approximately 400 μm. The size of the second through-hole 14 is the same as the size of the first through-hole 13.

[0038] In the first through-hole 13 of the second substrate 3, a first through-electrode 15 is provided as a through-electrode on the Z-negative direction side of the common terminal 11. The first through-electrode 15 is conductive to the common terminal 11. In the second through-hole 14 of the second substrate 3, a second through-electrode 16 is provided as a through-electrode on the Z-negative direction side of the drive terminal 12. The second through-electrode 16 is conductive to the drive terminal 12.

[0039] The second substrate 3 has an opening 17 on the positive X-direction side of the second groove 9. The opening 17 extends from the second surface 3a to the third surface 3b. The opening 17 and the second groove 9 are connected by a first connecting groove 18. The four second grooves 9 are connected to each other by second connecting grooves 19.

[0040] The second substrate 3 is bonded and fixed to the first substrate 4. The second groove 9 is not sealed because it is connected to the open hole 17, the first connecting groove 18, and the second connecting groove 19. When the first substrate 4 vibrates, the air inside the second groove 9 is connected to the outside air, so the pressure inside the second groove 9 does not easily fluctuate. Therefore, the first substrate 4 becomes more susceptible to vibration.

[0041] The third substrate 2 and the third surface 3b of the second substrate 3 are disposed opposite each other. The third substrate 2 has a common connection terminal 21 serving as a second electrode at a position corresponding to the first through electrode 15. The common connection terminal 21 is conductive to the first through electrode 15. The third substrate 2 has a drive connection terminal 22 serving as a second electrode at a position corresponding to the second through electrode 16. The drive connection terminal 22 is conductive to the second through electrode 16.

[0042] According to this configuration, the common connection terminal 21 is connected to the first through electrode 15. The drive connection terminal 22 is connected to the second through electrode 16. Therefore, by supplying power to the common connection terminal 21 and the drive connection terminal 22, power can be supplied to the component 7.

[0043] The third substrate 2 has an external common terminal 23 on the X-negative direction side of the common connection terminal 21. The external common terminal 23 and the common connection terminal 21 are electrically connected via wiring 24. The third substrate 2 has an external drive terminal 25 on the X-negative direction side of the drive connection terminal 22. The external drive terminal 25 and the drive connection terminal 22 are electrically connected via wiring 26.

[0044] Wiring 24 and wiring 26 are covered by resist 27. Common connection terminal 21, drive connection terminal 22, external common terminal 23, and external drive terminal 25 are exposed and not covered by resist 27. Common connection terminal 21 is conductive to the first through electrode 15. Drive connection terminal 22 is conductive to the second through electrode 16.

[0045] At the end of the second substrate 3 on the positive X-direction side, the corners on the positive Y-direction side and the corners on the negative Y-direction side are bonded and fixed to the third substrate 2 by a fixing adhesive 28. At the end of the second substrate 3 on the negative X-direction side, the first through electrode 15 and the second through electrode 16 are bonded and fixed to the third substrate 2 by a fixing adhesive 28.

[0046] Figure 2 It is to observe along Figure 1 A cross-sectional view of line AA. Figure 3 It is to observe along Figure 1 A cross-sectional view of the BB line. (See diagram.) Figure 2 as well as Figure 3As shown, element 7 is disposed at the location where the fourth hole 8 intersects with the second groove 9 when viewed from the first direction 6. Element 7 is disposed on the first surface 4a of the first substrate 4. Element 7 is composed of a driving electrode 7a, a piezoelectric film 7b, and a common electrode 7c, which are arranged overlappingly from the first surface 4a in the negative Z direction.

[0047] The piezoelectric film 7b is formed, for example, using a transition metal oxide with a perovskite structure. Specifically, the piezoelectric film 7b is formed using lead zirconate titanate containing Pb, Ti, and Zr.

[0048] Multiple driving electrodes 7a are connected to a driving wiring 29 extending along the X direction. The driving electrodes 7a and the driving wiring 29 are made of the same material. Multiple common electrodes 7c are connected to a common wiring 31 extending along the Y direction. The common electrodes 7c and the common wiring 31 are made of the same material.

[0049] An ultrasonic transducer 32 is constructed from a first substrate 4 and an element 7. A common electrode 7c is maintained at a predetermined reference potential. When a drive pulse signal is input to the drive electrode 7a, the element 7 deforms, causing the first substrate 4 to vibrate. This causes the ultrasonic transducer 32 to transmit ultrasonic waves in the positive Z direction. When an object is present in the positive Z direction of the electronic device 1, the ultrasonic waves are reflected by the object. When the reflected ultrasonic waves reach the ultrasonic transducer 32 through the fourth hole 8 of the fourth substrate 5, the first substrate 4 vibrates in response to the sound pressure of the ultrasonic waves. The piezoelectric film 7b deforms due to the vibration of the first substrate 4, creating a potential difference between the drive electrode 7a and the common electrode 7c. Therefore, a received signal corresponding to the sound pressure of the received ultrasonic waves is output from the drive electrode 7a of the ultrasonic transducer 32. In other words, ultrasonic waves are detected.

[0050] By measuring the time from when electronic device 1 sends out ultrasonic waves to when it receives ultrasonic waves, the distance between electronic device 1 and an object can be measured.

[0051] Figure 4 This is a view of the first substrate 4 as seen from the side of the second substrate 3. (See diagram below.) Figure 4 As shown, four drive wires 29 extending along the X direction are arranged on the first surface 4a. Each drive wire 29 is electrically connected to the drive terminal 12 on the negative X-direction side. Four common wires 31 extending along the Y direction are arranged on the first surface 4a. Each common wire 31 is electrically connected to the common terminal 11 on the negative Y-direction side.

[0052] Figure 5 It is to observe along Figure 1 A cross-sectional view of the CC line. (See diagram below.) Figure 5 As shown, the first through electrode 15 electrically connects the common terminal 11 and the common connection terminal 21. The second through electrode 16 electrically connects the drive terminal 12 and the drive connection terminal 22.

[0053] The third substrate 2 is disposed opposite to the third surface 3b of the second substrate 3. The third substrate 2 has a common connection terminal 21 that is connected to the first through electrode 15. The third substrate 2 has a drive connection terminal 22 that is connected to the second through electrode 16.

[0054] According to this configuration, the common connection terminal 21 is connected to the first through electrode 15. The drive connection terminal 22 is connected to the second through electrode 16. Therefore, by supplying power to the common connection terminal 21 and the drive connection terminal 22, power can be supplied to the component 7.

[0055] The first through electrode 15 and the second through electrode 16 are made of a conductive adhesive. Specifically, the first through electrode 15 and the second through electrode 16 are resins containing silver filler. The resin is a resin obtained by heating and curing a resin-based adhesive. As a resin-based adhesive, for example, epoxy resin, polyurethane resin, or silicone resin-based adhesive can be used.

[0056] During the formation of the first through electrode 15, the adhesive applied to the first through hole 13 is heated and dried. During the formation of the second through electrode 16, the adhesive applied to the second through hole 14 is heated and dried. Each adhesive shrinks and solidifies.

[0057] A gap 33 is provided in a portion of the first through electrode 15 and the second through electrode 16. According to this configuration, even if the materials of the first through electrode 15 and the second through electrode 16 shrink during their formation, the gap 33 will expand. Therefore, the stress causing the first through hole 13 and the second through hole 14 to shrink is reduced, thus reducing the shrinkage of the first through hole 13 and the second through hole 14. As a result, the occurrence of cracks on the first substrate 4 can be reduced.

[0058] The volume of the void 33 accounts for more than 1% and less than 50% of the volume of the first through-hole 13. According to this configuration, since the volume of the void 33 accounts for more than 1% of the volume of the first through-hole 13, even if the material of the first through-hole 15 shrinks during its formation, the shrinkage of the first through-hole 13 is reduced. Since the volume of the void 33 accounts for less than 50% of the volume of the first through-hole 13, the resistance of the first through-hole 15 can be reduced. Furthermore, poor conductivity caused by a break in the first through-hole 15 can be suppressed.

[0059] Similarly, the volume of the void 33 accounts for more than 1% and less than 50% of the volume of the second through hole 14. Therefore, even if the material of the second through electrode 16 shrinks, the shrinkage of the second through hole 14 will be reduced. The resistance of the second through electrode 16 can be reduced. Furthermore, poor conductivity caused by the breakage of the second through electrode 16 can be suppressed.

[0060] The length of the second through hole 14 in the first direction 6 is set as the length of the first through hole 34. The length of the gap 33 in the second through hole 14 in the first direction 6 is set as the length of the first gap 35.

[0061] The ratio of the length of the first gap 35 to the length of the first through hole 34 is more than 25% and less than 95%.

[0062] According to this configuration, since the ratio of the length of the gap 33 in the first direction 6 to the length of the second through hole 14 in the first direction 6 is 25% or more, the shrinkage of the second through hole 14 is reduced even when the material of the second through electrode 16 shrinks during its formation. Since the ratio of the length of the gap 33 in the first direction 6 to the length of the second through hole 14 in the first direction 6 is 95% or less, the resistance of the second through electrode 16 can be reduced. Furthermore, poor conductivity caused by a break in the second through electrode 16 can be suppressed.

[0063] Similarly, the ratio of the length of the gap 33 in the first direction 6 to the length of the first through hole 13 in the first direction 6 is 25% or more and 95% or less. Therefore, even if the material of the first through electrode 15 shrinks, the shrinkage of the first through hole 13 will be reduced. The resistance of the first through electrode 15 can be reduced. Furthermore, poor conductivity caused by the breakage of the first through electrode 15 can be suppressed.

[0064] The long side direction of the first through hole 13 and the second through hole 14 in the direction orthogonal to the first direction 6 is defined as the second direction 36. The second direction 36 is equivalent to the Y direction. The length of the second through hole 14 in the second direction 36 is defined as the second through hole length 37. The length of the gap 33 in the second through hole 14 in the second direction 36 is defined as the second gap length 38. The ratio of the second gap length 38 to the second through hole length 37 is more than 10% and less than 60%.

[0065] According to this configuration, since the ratio of the length of the gap 33 in the second direction 36 to the length of the second through hole 14 in the second direction 36 is 10% or more, the shrinkage of the second through hole 14 is reduced even when the material of the second through electrode 16 shrinks during its formation. Since the ratio of the length of the gap 33 in the second direction 36 to the length of the second through hole 14 in the second direction 36 is 60% or less, the resistance of the second through electrode 16 can be reduced. Furthermore, poor conductivity caused by a break in the second through electrode 16 can be suppressed.

[0066] Similarly, the ratio of the length of the gap 33 in the second direction 36 to the length of the first through hole 13 in the second direction 36 is 10% or more and 60% or less. Therefore, even if the material of the first through electrode 15 shrinks, the shrinkage of the first through hole 13 will be reduced. The resistance of the first through electrode 15 can be reduced. Furthermore, poor conductivity caused by the breakage of the first through electrode 15 can be suppressed.

[0067] Next, the manufacturing methods of the first through electrode 15 and the second through electrode 16 will be described. Figure 6 As shown, a second substrate 3, a first substrate 4, and a fourth substrate 5 are prepared. The first substrate 4 is formed by oxidizing one side of the fourth substrate 5.

[0068] A driving electrode 7a, driving wiring 29, piezoelectric film 7b, common electrode 7c, common wiring 31, common terminal 11, and driving terminal 12 are formed on the first substrate 4. These elements are formed using film deposition methods such as sputtering, photolithography, and dry etching. The fourth hole 8 of the fourth substrate 5 is formed using photolithography and wet etching. The second trench 9, first through hole 13, second through hole 14, open hole 17, first connecting trench 18, and second connecting trench 19 of the second substrate 3 are formed using photolithography and wet etching. Next, the second substrate 3 is bonded and fixed to the first substrate 4.

[0069] The first through electrode 15 and the second through electrode 16 are formed using a stencil printing method. The stencil printing method is a stencil printing method similar to screen printing. A stencil 39 is overlapped and disposed on the third surface 3b of the second substrate 3. The stencil 39 has holes 39a of the same shape as the first through hole 13 and the second through hole 14. It should be noted that the formation of the first through electrode 15 and the second through electrode 16 is not particularly limited. For example, a distributor can also be used to form the first through electrode 15 and the second through electrode 16. In this case, a gap 33 can also be formed.

[0070] Slurry 41 is placed on the template 39 on the negative Y-direction side. Slurry 41 is a paste-like resin-based adhesive containing silver filler. Slurry 41 contains solvent and has fluidity. Slurry 41 is sandwiched between a scraper 42 and the template 39. Scraper 42 is a plate that is long in the positive X-direction. The positive Y-direction is set as the first sliding direction 43. With the scraper 42 on the negative Y-direction side in contact with the template 39, the scraper 42 slides in the first sliding direction 43. Slurry 41 is scraped and pressed by the scraper 42 and moves in the first sliding direction 43.

[0071] like Figure 7 As shown, when the scraper 42 passes through the first through hole 13, a portion of the slurry 41 enters the first through hole 13 through hole 39a. A portion of the slurry 41 moves along the wall of the first through hole 13 on the positive Y-direction side, i.e., the first wall 13a, to the common terminal 11. A portion of the slurry 41 that reaches the common terminal 11 moves along the common terminal 11 in the negative Y-direction. The slurry 41 that moves along the common terminal 11 in the negative Y-direction does not reach the wall of the first through hole 13 on the negative Y-direction side, i.e., the second wall 13b. By adjusting the viscosity of the slurry 41, it is possible to prevent the slurry 41 from reaching the second wall 13b.

[0072] The wall on the positive Y-direction side of the second through hole 14 is designated as the third wall 14a. The wall on the negative Y-direction side of the second through hole 14 is designated as the fourth wall 14b. A portion of the slurry 41 in the second through hole 14 moves along the third wall 14a to the drive terminal 12. A portion of the slurry 41 that reaches the drive terminal 12 moves along the drive terminal 12 in the negative Y-direction. The portion of the slurry 41 that moves along the drive terminal 12 in the negative Y-direction does not reach the fourth wall 14b.

[0073] like Figure 8 As shown, the result is that slurry 41 is dispensed into the first through hole 13 and the second through hole 14. Slurry 41 is disposed biased towards the positive Y-direction side of the first through hole 13 and the second through hole 14. At the common terminal 11 and the drive terminal 12, slurry 41 is also disposed biased towards the positive Y-direction side. The slurry 41 disposed into the first through hole 13 and the second through hole 14 by the scraper 42 moving in the first sliding direction 43 is designated as the first slurry 41a.

[0074] like Figure 9 As shown, the negative Y direction is defined as the second sliding direction 44. The second sliding direction 44 is the opposite direction to the first sliding direction 43. When the scraper 42 on the positive Y direction side is in contact with the mold 39, the scraper 42 slides in the second sliding direction 44. The slurry 41 is scraped and pressed by the scraper 42 and moves in the second sliding direction 44.

[0075] like Figure 10As shown, when the scraper 42 passes through the second through hole 14, a portion of the slurry 41 enters the second through hole 14 through hole 39a. The slurry 41 disposed in the second through hole 14 by the scraper 42 moving in the second sliding direction 44 is designated as the second slurry 41b. A portion of the second slurry 41b moves along the fourth wall 14b toward the drive terminal 12. Since the first slurry 41a already exists on the drive terminal 12, the second slurry 41b that reaches the first slurry 41a moves along the first slurry 41a in the positive Y direction. The second slurry 41b moving along the fourth wall 14b toward the drive terminal 12 does not reach the drive terminal 12. By adjusting the viscosity of the slurry 41, it is possible to prevent the second slurry 41b from reaching the drive terminal 12.

[0076] As the scraper 42 passes through the first through hole 13, a portion of the slurry 41 enters the first through hole 13 through hole 39a. A portion of the slurry 41 moves along the second wall 13b toward the common terminal 11. Since the first slurry 41a already exists on the common terminal 11, the portion of the slurry 41 that reaches the first slurry 41a moves in the positive Y direction along the first slurry 41a. The portion of the slurry 41 that moves along the second wall 13b toward the common terminal 11 does not reach the common terminal 11.

[0077] like Figure 11 As shown, slurry 41 is dispensed into the first through hole 13 and the second through hole 14. In the first through hole 13, a gap 33 is formed at the intersection of the second wall 13b and the common terminal 11. In the second through hole 14, a gap 33 is formed at the intersection of the fourth wall 14b and the drive terminal 12. The gap 33 is provided as part of the slurry 41 that forms part of the first through electrode 15 and the second through electrode 16. The gap 33 is a sealed space. Air is filled in the gap 33. The air within the gap 33 cannot move outside the first through hole 13 and the second through hole 14.

[0078] It should be noted that in this embodiment, the first sliding direction 43 is the positive Y direction, and the second sliding direction 44 is the negative Y direction. In this case, a gap 33 is formed on the negative Y direction side of the first through hole 13 and the second through hole 14. Alternatively, the first sliding direction 43 can be the negative Y direction, and the second sliding direction 44 can be the positive Y direction. In this case, a gap 33 is formed in the first through hole 13 at the location where the first wall 13a intersects with the common terminal 11. Similarly, a gap 33 is formed in the second through hole 14 at the location where the third wall 14a intersects with the drive terminal 12.

[0079] like Figure 12As shown, the template 39 is removed from the second substrate 3. The slurry 41 in the first through-hole 13 and the second through-hole 14 is heated and dried. As a result, in the first through-hole 13, the slurry 41 solidifies to form the first through-electrode 15. In the second through-hole 14, the slurry 41 solidifies to form the second through-electrode 16. A portion of the first through-electrode 15 and the second through-electrode 16 has a void 33. At this time, due to the vaporization of the solvent contained in the slurry 41, the slurry 41 shrinks. The volume of the first through-electrode 15 and the second through-electrode 16 is smaller than the volume of the slurry 41.

[0080] Even when the slurry 41 shrinks during the formation of the first through-hole 15 and the second through-hole 16, the voids 33 expand. As a result, the stress that causes the first through-hole 13 and the second through-hole 14 to shrink is reduced, thus reducing the shrinkage of the first through-hole 13 and the second through-hole 14.

[0081] According to this configuration, a resin slurry 41 containing silver filler is applied to the first through-hole 13 and the second through-hole 14. Through solvent evaporation of the slurry 41, voids 33 can be formed in a portion of the first through-electrode 15 and the second through-electrode 16. Specifically, by applying the slurry 41 to the first through-hole 13 and the second through-hole 14 multiple times, voids 33 can be formed in a portion of the first through-electrode 15 and the second through-electrode 16.

[0082] exist Figure 13 In the diagram, the horizontal axis represents the area ratio of the first through electrode 15 to the area of ​​the first through hole 13 when viewed from the first direction 6. The vertical axis represents the inter-terminal resistance between the common terminal 11 and the common connection terminal 21.

[0083] If the resistance between terminals is less than 1 ohm, the first through electrode 15 can be used without any problems. In this case, the area ratio of the first through electrode 15 is 3% or more.

[0084] When the volume of the gap 33 accounts for less than 50% of the volume of the first through hole 13, the ratio of the area of ​​the first through electrode 15 to the area of ​​the first through hole 13 is greater than 3%, and therefore the inter-terminal resistance between the common terminal 11 and the common connection terminal 21 is less than 1 ohm. Thus, the first through electrode 15 can be used without problems.

[0085] When the ratio of the length of the gap 33 in the second direction 36 to the length of the first through hole 13 in the second direction 36 is less than 60%, the ratio of the area of ​​the first through electrode 15 to the area of ​​the first through hole 13 is greater than 3%, and therefore the inter-terminal resistance between the common terminal 11 and the common connection terminal 21 is less than 1 ohm. Therefore, the first through electrode 15 can be used without problems.

[0086] Second Implementation Method

[0087] In the first embodiment described above, element 7 is a piezoelectric element. Alternatively, element 7 can also be a pressure sensing element or an inertial sensing element. Similarly, the through electrode can also have a structure including the gap 33. This can suppress adverse conditions when the through electrode contracts.

Claims

1. An electronic device, characterized in that, have: A first substrate includes a first surface, an element disposed on the first surface, and a first electrode connected to the element disposed on the first surface; as well as The second substrate has a second surface and a third surface, wherein the second surface is disposed opposite to the first surface. The second substrate has a through hole at a position corresponding to the first electrode, extending from the second surface to the third surface. A through electrode, which is in communication with the first electrode, is provided in the through hole. A portion of the through electrode has an air-filled void. The gap is surrounded by the through electrode, the first electrode, and the second substrate.

2. The electronic device according to claim 1, characterized in that, The volume of the void accounts for more than 1% and less than 50% of the volume of the through hole.

3. The electronic device according to claim 1, characterized in that, When the stacking direction of the first substrate and the second substrate is set as the first direction, the ratio of the length of the gap in the first direction to the length of the through hole in the first direction is more than 25% and less than 95%.

4. The electronic device according to claim 3, characterized in that, When the direction orthogonal to the first direction is set as the second direction, the ratio of the length of the gap in the second direction to the length of the through hole in the second direction is more than 10% and less than 60%.

5. The electronic device according to any one of claims 1 to 4, characterized in that, The element is a piezoelectric element.

6. The electronic device according to claim 1, characterized in that, The through electrode is a resin containing silver filler.

7. The electronic device according to claim 1, characterized in that, The electronic device includes a third substrate having a second electrode that is connected to the through electrode and is disposed opposite to the third surface.

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