Electronic device and method for manufacturing the same

Abstract

To provide an electronic device less likely to cause cracks on a diaphragm due to contraction of through holes in an encapsulation plate, in a process of manufacturing a through electrode.SOLUTION: An electronic device 1 comprises: a first substrate 4 that includes a first surface 4a on which an element 7 and a common terminal 11 connected with the element 7 are arranged; a second substrate 3 that has a second surface 3a and a third surface 3b, the second surface 3a being arranged so as to be opposed to the first surface 4a. The second substrate 3 has a first through hole 13 penetrating through from the second surface 3a to the third surface 3b at a position corresponding to the common terminal 11. A first through electrode 15 conductive to the common terminal 11 is provided in the first through hole 13. A void 33 is provided at a part of the first through electrode 15.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to electronic devices. [Background technology]

[0002] Conventionally, electronic devices in which piezoelectric elements are arranged in a matrix are known. For example, Patent Document 1 discloses an electronic device that includes a sealing plate with an opening, a diaphragm that closes the opening, and a piezoelectric element that is mounted on the diaphragm and has a piezoelectric body sandwiched between an upper electrode and a lower electrode.

[0003] According to this, a diaphragm and a sealing plate are arranged opposite each other. The sealing plate limits the range in which the diaphragm vibrates. The frequency at which the diaphragm vibrates is determined by the size of the diaphragm surrounded by the opening in the sealing plate. A brittle material that does not easily absorb the vibrations of the diaphragm is used for the sealing plate.

[0004] A pair of through electrodes is arranged on the sealing plate. The upper electrode and the lower electrode are each electrically connected to the through electrodes. The sealing plate is arranged opposite the wiring substrate. The wiring substrate has pads. The through electrodes protrude toward the wiring substrate. The pads and the through electrodes are in electrical contact. The upper electrode and the lower electrode are each electrically connected to the pads via the through electrodes.

[0005] The through electrode is made of a resin-based adhesive containing a metal filler. When forming the through electrode, a liquid resin-based adhesive containing a metal filler is poured into the through hole. The liquid resin-based adhesive is heated and dried to solidify. At this time, the solvent contained in the liquid resin-based adhesive volatilizes. During the process of solidifying the resin-based adhesive, the volume of the resin-based adhesive shrinks. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-106183 Summary of the Invention [Problem to be solved by the invention]

[0007] In the electronic device of Patent Document 1, when the through electrode shrinks during the manufacturing process of the through electrode, the through hole in the sealing plate shrinks, which may cause a crack in the diaphragm. [Means for solving the problem]

[0008] The electronic device comprises a first substrate including a first surface on which an element is arranged and a first electrode connected to the element is arranged, and a second substrate having a second surface and a third surface, the second surface being arranged opposite the first surface, the second substrate having a through hole penetrating from the second surface to the third surface at a position corresponding to the first electrode, a through electrode electrically connected to the first electrode being provided in the through hole, and a void being provided in a portion of the through electrode. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic exploded perspective view showing the configuration of an electronic device according to a first embodiment. [Figure 2] FIG. 1 is a schematic cross-sectional side view showing a configuration of an electronic device. [Figure 3] FIG. 1 is a schematic cross-sectional side view showing a configuration of an electronic device. [Figure 4] FIG. 2 is a schematic plan view showing the configuration of a first substrate. [Figure 5] FIG. 2 is a schematic cross-sectional side view showing the configuration of a through electrode. [Figure 6] 5A and 5B are schematic cross-sectional side views for explaining a method for manufacturing a through electrode. [Figure 7] 5A and 5B are schematic cross-sectional side views for explaining a method for manufacturing a through electrode. [Figure 8] 5A and 5B are schematic cross-sectional side views for explaining a method for manufacturing a through electrode. [Figure 9] 5A and 5B are schematic cross-sectional side views for explaining a method for manufacturing a through electrode. [Figure 10] 5A and 5B are schematic cross-sectional side views for explaining a method for manufacturing a through electrode. [Figure 11] 5A and 5B are schematic cross-sectional side views for explaining a method for manufacturing a through electrode. [Figure 12] 5A and 5B are schematic cross-sectional side views for explaining a method for manufacturing a through electrode. [Figure 13] 10A and 10B are diagrams for explaining the relationship between the area ratio of the through electrodes to the through holes and the inter-terminal resistance. DETAILED DESCRIPTION OF THE INVENTION

[0010] First embodiment In this embodiment, a characteristic example of an electronic device and an electronic device manufacturing method for manufacturing the electronic device will be described.

[0011] As shown in Figure 1, in electronic device 1, third substrate 2, second substrate 3, first substrate 4, and fourth substrate 5 are stacked in this order in the Z direction. In the Z direction, the fourth substrate 5 side is the Z positive direction, and the third substrate 2 side is the Z negative direction. The direction along the Z positive direction is called first direction 6. First direction 6 is the stacking direction of first substrate 4 and second substrate 3.

[0012] 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 longitudinal directions 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 have the same shape. The third substrate 2 is larger than the second substrate 3, the first substrate 4, and the fourth substrate 5.

[0013] The longitudinal direction of the third substrate 2 is defined as the X direction, and the lateral direction of the third substrate 2 is defined as the Y direction. The X direction, Y direction, and Z direction are perpendicular to each other.

[0014] 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. With this configuration, the elements 7 are piezoelectric elements. By applying an AC voltage to the elements 7, the electronic device 1 can vibrate the first substrate 4 and emit ultrasonic waves. The first substrate 4 is also called a diaphragm.

[0015] There is no particular limitation on the number of elements 7. In this embodiment, for example, the elements 7 are arranged in a 4-row, 4-column array, so the number of elements 7 is 16.

[0016] The fourth substrate 5 has four fourth holes 8 that are long in the X direction. When viewed from the first direction 6, the shape of the fourth holes 8 is a parallelogram. The fourth substrate 5 is formed from a silicon single crystal substrate. The fourth holes 8 are formed by wet etching. The side surfaces of the fourth holes 8 are crystal planes with a slow etching rate. In a silicon single crystal substrate, the crystal planes with a slow etching rate are parallelograms, so the shape of the fourth holes 8 is a parallelogram. The fourth holes 8 penetrate the fourth substrate 5. The fourth holes 8 are arranged in a position opposite the arrangement of the elements 7. The number of fourth holes 8 is not limited to four.

[0017] The second substrate 3 has a second surface 3a and a third surface 3b. The second surface 3a is disposed opposite the first surface 4a of the first substrate 4. The second substrate 3 has four second grooves 9 on the second surface 3a that are long in the Y direction. When viewed from the first direction 6, the second grooves 9 have a parallelogram shape. The second substrate 3 is formed from a silicon single crystal substrate. The second grooves 9 are formed by wet etching. Therefore, the second grooves 9 have a parallelogram shape. The second grooves 9 are disposed in a position opposite the arrangement of the elements 7.

[0018] When viewed from the first direction 6, the element 7 is disposed at the location where the fourth hole 8 and the second groove 9 intersect. Therefore, at the location where the element 7 is disposed, the first substrate 4 can vibrate in the positive Z direction and the negative Z direction.

[0019] The first substrate 4 and the fourth substrate 5 are integrated together. The material of the first substrate 4 is silicon oxide, and the first substrate 4 is formed by oxidizing the fourth substrate 5.

[0020] The first substrate 4 has a first surface 4a provided with a common terminal 11 as a first electrode and a driving terminal 12 as a first electrode. The common terminal 11 and the driving terminal 12 are electrically connected to the element 7.

[0021] The second substrate 3 has a first through hole 13 as a through hole that penetrates from the second surface 3a to the third surface 3b at a position corresponding to the common terminal 11. The second substrate 3 has a second through hole 14 as a through hole that penetrates from the second surface 3a to the third surface 3b at a position corresponding to the drive terminal 12.

[0022] 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 about 1 mm. The width of the first through hole 13 in the X direction is about 350 μm. The thickness of the second substrate 3 is about 400 μm. The size of the second through hole 14 is the same as the size of the first through hole 13.

[0023] A first through electrode 15 serving as a through electrode is provided in the first through hole 13 of the second substrate 3 on the negative Z direction side of the common terminal 11. The first through electrode 15 is electrically connected to the common terminal 11. A second through electrode 16 serving as a through electrode is provided in the second through hole 14 of the second substrate 3 on the negative Z direction side of the drive terminal 12. The second through electrode 16 is electrically connected to the drive terminal 12.

[0024] The second substrate 3 has an open hole 17 on the X-positive side of the second groove 9. The open hole 17 penetrates from the second surface 3a to the third surface 3b. The open hole 17 and the second groove 9 are connected by a first communicating groove 18. The four second grooves 9 are connected to one another by a second communicating groove 19.

[0025] The second substrate 3 and the first substrate 4 are adhesively fixed together. The second groove 9 is not sealed because it is connected to the open hole 17, the first communicating groove 18, and the second communicating groove 19. When the first substrate 4 vibrates, the air in the second groove 9 is connected to the outside air, so the pressure inside the second groove 9 does not easily fluctuate. For this reason, the first substrate 4 is prone to vibrating.

[0026] The third substrate 2 is disposed opposite the third surface 3b of the second substrate 3. The third substrate 2 has a common connection terminal 21 as a second electrode at a position corresponding to the first through-hole electrode 15. The common connection terminal 21 is electrically connected to the first through-hole electrode 15. The third substrate 2 has a drive connection terminal 22 as a second electrode at a position corresponding to the second through-hole electrode 16. The drive connection terminal 22 is electrically connected to the second through-hole electrode 16.

[0027] According to this configuration, the common connection terminal 21 is electrically connected to the first through-electrode 15. The drive connection terminal 22 is electrically 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 element 7.

[0028] The third substrate 2 has an external common terminal 23 on the negative X side of the common connection terminal 21. The external common terminal 23 and the common connection terminal 21 are electrically connected by a wiring 24. The third substrate 2 has an external drive terminal 25 on the negative X side of the drive connection terminal 22. The external drive terminal 25 and the drive connection terminal 22 are electrically connected by a wiring 26.

[0029] The wiring 24 and the wiring 26 are covered with a resist 27. The common connection terminal 21, the drive connection terminal 22, the external common terminal 23, and the external drive terminal 25 are exposed without being covered with the resist 27. The common connection terminal 21 is electrically connected to the first through electrode 15. The drive connection terminal 22 is electrically connected to the second through electrode 16.

[0030] At the end of the second substrate 3 on the X-positive side, the corner on the Y-positive side and the corner on the Y-negative side are bonded and fixed to the third substrate 2 with a fixing adhesive 28. At the end of the second substrate 3 on the X-negative side, the peripheries of the first through electrode 15 and the second through electrode 16 are bonded and fixed to the third substrate 2 with the fixing adhesive 28.

[0031] Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. Fig. 3 is a cross-sectional view taken along line BB in Fig. 1. As shown in Figs. 2 and 3, element 7 is disposed at the location where fourth hole 8 and second groove 9 intersect when viewed from first direction 6. Element 7 is disposed on first surface 4a of first substrate 4. Element 7 is composed of drive electrode 7a, piezoelectric film 7b, and common electrode 7c, which are stacked in the negative Z direction from first surface 4a.

[0032] The piezoelectric film 7b is made of, for example, a transition metal oxide having a perovskite structure, specifically, lead zirconate titanate containing Pb, Ti, and Zr.

[0033] The plurality of drive electrodes 7a are electrically connected to drive wiring 29 extending in the X direction. The drive electrodes 7a and the drive wiring 29 are made of the same material. The plurality of common electrodes 7c are electrically connected to common wiring 31 extending in the Y direction. The common electrodes 7c and the common wiring 31 are made of the same material.

[0034] The first substrate 4 and the element 7 form an ultrasonic transducer 32. The 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 and the first substrate 4 vibrates. This causes the ultrasonic transducer 32 to transmit ultrasonic waves in the positive Z direction. If an object is present on the positive Z side of the electronic device 1, the ultrasonic waves are reflected by the object. When the reflected ultrasonic waves pass through the fourth hole 8 in the fourth substrate 5 and reach the ultrasonic transducer 32, the first substrate 4 vibrates in response to the sound pressure of the ultrasonic waves. The vibration of the first substrate 4 deforms the piezoelectric film 7b, generating a potential difference between the drive electrode 7a and the common electrode 7c. As a result, a reception 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.

[0035] By measuring the time from when the electronic device 1 transmits the ultrasonic wave until when it receives it, the distance between the electronic device 1 and the object can be measured.

[0036] 4 is a view of the first substrate 4 viewed from the second substrate 3 side. As shown in FIG. 4, four drive wires 29 extending in the X direction are arranged on the first surface 4a. The drive wires 29 are integrated on the negative X direction side and electrically connected to the drive terminals 12. Four common wires 31 extending in the Y direction are arranged on the first surface 4a. The common wires 31 are integrated on the negative Y direction side and electrically connected to the common terminals 11.

[0037] Fig. 5 is a cross-sectional view taken along line CC in Fig. 1. As shown in Fig. 5, 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.

[0038] The third substrate 2 is disposed opposite the third surface 3b of the second substrate 3. The third substrate 2 has a common connection terminal 21 that is electrically connected to the first through electrode 15. The third substrate 2 has a drive connection terminal 22 that is electrically connected to the second through electrode 16.

[0039] According to this configuration, the common connection terminal 21 is electrically connected to the first through-electrode 15. The drive connection terminal 22 is electrically 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 element 7.

[0040] 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 made of a resin containing a silver filler. The resin is obtained by heating and solidifying a resin-based adhesive. Examples of the resin-based adhesive that can be used include epoxy resin, urethane resin, and silicone resin-based adhesives.

[0041] In the process of forming first through electrode 15, the adhesive poured into first through hole 13 is heated and dried. In the process of forming second through electrode 16, the adhesive poured into second through hole 14 is heated and dried. Each adhesive shrinks and hardens.

[0042] A void 33 is provided in a part of the first through electrode 15 and the second through electrode 16. With this configuration, even if the material of the first through electrode 15 and the second through electrode 16 shrinks when the first through electrode 15 and the second through electrode 16 are formed, the void 33 expands. Therefore, the stress that shrinks the first through hole 13 and the second through hole 14 is reduced, and therefore the shrinkage of the first through hole 13 and the second through hole 14 is reduced. As a result, the occurrence of cracks in the first substrate 4 can be reduced.

[0043] The ratio of the volume of the voids 33 to the volume of the first through hole 13 is 1% or more and 50% or less. According to this configuration, since the ratio of the volume of the voids 33 to the volume of the first through hole 13 is 1% or more, even if the material of the first through electrode 15 shrinks when forming the first through hole 13, shrinkage of the first through hole 13 is reduced. Since the ratio of the volume of the voids 33 to the volume of the first through hole 13 is 50% or less, the electrical resistance of the first through electrode 15 can be reduced. Furthermore, poor conductivity due to disconnection of the first through electrode 15 can be suppressed.

[0044] Similarly, the ratio of the volume of the voids 33 to the volume of the second through hole 14 is 1% or more and 50% or less. Therefore, even if the material of the second through electrode 16 shrinks, the shrinkage of the second through hole 14 is reduced. The electrical resistance of the second through electrode 16 can be reduced. Furthermore, poor conductivity due to disconnection of the second through electrode 16 can be suppressed.

[0045] The length of second through hole 14 in first direction 6 is defined as first through hole length 34. The length of gap 33 in second through hole 14 in first direction 6 is defined as first gap length 35. The ratio of first gap length 35 to first through hole length 34 is 25% or more and 95% or less.

[0046] According to this configuration, the ratio of the length of the void 33 in the first direction 6 to the length of the second through hole 14 in the first direction 6 is 25% or more, so even if the material of the second through electrode 16 shrinks when forming the second through hole 16, shrinkage of the second through hole 14 is reduced. Since the ratio of the length of the void 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 electrical resistance of the second through electrode 16 can be reduced. Furthermore, poor conductivity due to disconnection of the second through electrode 16 can be suppressed.

[0047] Similarly, the ratio of the length of the void 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 is reduced. The electrical resistance of the first through electrode 15 can be reduced. Furthermore, poor conductivity due to disconnection of the first through electrode 15 can be suppressed.

[0048] Among the directions perpendicular to the first direction 6, the longitudinal direction of the first through hole 13 and the second through hole 14 is defined as a second direction 36. The second direction 36 corresponds to the Y direction. The length of the second through hole 14 in the second direction 36 is defined as a 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 a second gap length 38. The ratio of the second gap length 38 to the second through hole length 37 is 10% or more and 60% or less.

[0049] According to this configuration, the ratio of the length of the void 33 in the second direction 36 to the length of the second through hole 14 in the second direction 36 is 10% or more, so even if the material of the second through electrode 16 shrinks when forming the second through hole 16, shrinkage of the second through hole 14 is reduced. Since the ratio of the length of the void 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 electrical resistance of the second through electrode 16 can be reduced. Furthermore, poor conductivity due to disconnection of the second through electrode 16 can be suppressed.

[0050] Similarly, the ratio of the length of the void 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 is reduced. The electrical resistance of the first through electrode 15 can be reduced. Furthermore, poor conductivity due to disconnection of the first through electrode 15 can be suppressed.

[0051] Next, a method for manufacturing the first through electrode 15 and the second through electrode 16 will be described. As shown in Fig. 6, a second substrate 3, a first substrate 4, and a fourth substrate 5 are prepared. The first substrate 4 is formed by oxidizing one surface of the fourth substrate 5.

[0052] The first substrate 4 is formed with a drive electrode 7a, drive wiring 29, piezoelectric film 7b, common electrode 7c, common wiring 31, common terminal 11, and drive terminal 12. These elements are formed using a film formation method such as sputtering, photolithography, dry etching, etc. The fourth hole 8 in the fourth substrate 5 is formed using a photolithography method, wet etching, etc. The second groove 9, first through hole 13, second through hole 14, open hole 17, first communicating groove 18, and second communicating groove 19 in the second substrate 3 are formed using a photolithography method, wet etching, etc. Next, the second substrate 3 is adhesively fixed to the first substrate 4.

[0053] The first through electrode 15 and the second through electrode 16 are formed by stencil printing. Stencil printing is a leak printing method similar to silk screening. A stencil 39 is placed on the third surface 3b of the second substrate 3. The stencil 39 has holes 39a having the same shapes as the first through holes 13 and the second through holes 14. The formation of the first through electrode 15 and the second through electrode 16 is not particularly limited. For example, the first through electrode 15 and the second through electrode 16 may be formed using a dispenser. In this case, the void 33 can also be formed.

[0054] Paste 41 is placed on the stencil 39 on the Y negative side. The paste 41 is a paste-like resin adhesive containing silver filler. The paste 41 contains a solvent and is fluid. The paste 41 is sandwiched between a squeegee 42 and the stencil 39. The squeegee 42 is a plate that is long in the X positive direction. The Y positive direction is defined as a first sliding direction 43. With the squeegee 42 on the Y negative side in contact with the stencil 39, the squeegee 42 is slid in the first sliding direction 43. The paste 41 is pushed by the squeegee 42 and moves in the first sliding direction 43.

[0055] As shown in FIG. 7, when the squeegee 42 passes through the first through hole 13, part of the paste 41 passes through the hole 39a and enters the first through hole 13. Part of the paste 41 moves along the first wall 13a, which is the wall of the first through hole 13 on the Y-positive side, to the common terminal 11. Part of the paste 41 that reaches the common terminal 11 moves along the common terminal 11 in the Y-negative direction. The paste 41 that moves in the Y-negative direction along the common terminal 11 does not reach the second wall 13b, which is the wall of the first through hole 13 on the Y-negative side. By adjusting the viscosity of the paste 41, it is possible to prevent the paste 41 from reaching the second wall 13b.

[0056] The wall on the Y-positive side of second through hole 14 is referred to as third wall 14a. The wall on the Y-negative side of second through hole 14 is referred to as fourth wall 14b. In second through hole 14, part of paste 41 also moves along third wall 14a to drive terminal 12. Part of paste 41 that reaches drive terminal 12 moves in the Y-negative direction along drive terminal 12. Paste 41 moving in the Y-negative direction along drive terminal 12 does not reach fourth wall 14b.

[0057] 8, as a result, paste 41 is poured into first through hole 13 and second through hole 14. Paste 41 is arranged biased toward the Y positive side of first through hole 13 and second through hole 14. Paste 41 is also arranged biased toward the Y positive side of common terminal 11 and drive terminal 12. By squeegee 42 moving in first sliding direction 43, paste 41 arranged in first through hole 13 and second through hole 14 becomes first paste 41a.

[0058] As shown in Figure 9, the negative Y direction is defined as a second sliding direction 44. The second sliding direction 44 is the opposite direction to the first sliding direction 43. The squeegee 42 on the positive Y direction side is slid in the second sliding direction 44 while in contact with the stencil 39. The paste 41 is pushed by the squeegee 42 and moves in the second sliding direction 44.

[0059] As shown in FIG. 10 , when the squeegee 42 passes through the second through hole 14, a portion of the paste 41 passes through the hole 39a and enters the second through hole 14. The paste 41 disposed in the second through hole 14 by the squeegee 42 moving in the second sliding direction 44 is referred to as the second paste 41b. A portion of the second paste 41b moves along the fourth wall 14b toward the drive terminal 12. Because the first paste 41a is already present on the drive terminal 12, the second paste 41b that reaches the first paste 41a moves along the first paste 41a in the positive Y direction. The second paste 41b that moves along the fourth wall 14b toward the drive terminal 12 does not reach the drive terminal 12. Adjusting the viscosity of the paste 41 makes it possible to prevent the second paste 41b from reaching the drive terminal 12.

[0060] When the squeegee 42 passes through the first through hole 13, part of the paste 41 passes through the hole 39a and enters the first through hole 13. Part of the paste 41 moves along the second wall 13b toward the common terminal 11. Because the first paste 41a is already present on the common terminal 11, the paste 41 that reaches the first paste 41a moves in the positive Y direction along the first paste 41a. The paste 41 that moves along the second wall 13b toward the common terminal 11 does not reach the common terminal 11.

[0061] As shown in FIG. 11 , paste 41 is poured into the first through hole 13 and the second through hole 14. A gap 33 is formed in the first through hole 13 at the location where the second wall 13b intersects with the common terminal 11. A gap 33 is formed in the second through hole 14 at the location where the fourth wall 14b intersects with the drive terminal 12. The gap 33 is provided in a portion of the paste 41 that will become the first through electrode 15 and the second through electrode 16. The gap 33 is an enclosed space. Air is filled into the gap 33. The air in the gap 33 cannot move out of the first through hole 13 and the second through hole 14.

[0062] In this embodiment, the first sliding direction 43 is the Y-positive direction, and the second sliding direction 44 is the Y-negative direction. In this case, a gap 33 is formed on the Y-negative side of the first through hole 13 and the second through hole 14. The first sliding direction 43 may be the Y-negative direction, and the second sliding direction 44 may be the Y-positive direction. In this case, the gap 33 is formed in the first through hole 13 at a location where the first wall 13a and the common terminal 11 intersect. The gap 33 is formed in the second through hole 14 at a location where the third wall 14a and the drive terminal 12 intersect.

[0063] As shown in FIG. 12, the stencil 39 is removed from the second substrate 3. The paste 41 in the first through hole 13 and the second through hole 14 is heated and dried. As a result, the paste 41 in the first through hole 13 solidifies to become the first through electrode 15. The paste 41 in the second through hole 14 solidifies to become the second through electrode 16. A gap 33 is formed in a part of the first through electrode 15 and the second through electrode 16. At this time, the solvent contained in the paste 41 evaporates, causing the paste 41 to shrink. The volumes of the first through electrode 15 and the second through electrode 16 become smaller than the volume of the paste 41.

[0064] Even if the paste 41 shrinks when the first through electrode 15 and the second through electrode 16 are formed, the voids 33 expand. Therefore, the stress that shrinks the first through hole 13 and the second through hole 14 is reduced, and therefore the shrinkage of the first through hole 13 and the second through hole 14 is reduced.

[0065] According to this configuration, paste 41, which is a resin paste containing silver filler, is poured into first through hole 13 and second through hole 14. By volatilizing the solvent of paste 41, voids 33 can be formed in parts of first through electrode 15 and second through electrode 16. More specifically, by pouring paste 41 into first through hole 13 and second through hole 14 in multiple batches, voids 33 can be formed in parts of first through electrode 15 and second through electrode 16.

[0066] 13, the area ratio on the horizontal axis indicates the ratio of the area of ​​the first through electrode 15 to the area of ​​the first through hole 13 when viewed from the first direction 6. The inter-terminal resistance on the vertical axis indicates the electrical resistance between the common terminal 11 and the common connection terminal 21.

[0067] If the inter-terminal resistance is 1 ohm or less, 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.

[0068] When the ratio of the volume of the void 33 to the volume of the first through hole 13 is 50% or less, the ratio of the area of ​​the first through electrode 15 to the area of ​​the first through hole 13 is greater than 3%, so the inter-terminal resistance between the common terminal 11 and the common connection terminal 21 is 1 ohm or less. Therefore, the first through electrode 15 can be used without any problems.

[0069] 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 60% or less, the ratio of the area of ​​the first through electrode 15 to the area of ​​the first through hole 13 is greater than 3%, so the inter-terminal resistance between the common terminal 11 and the common connection terminal 21 is 1 ohm or less. Therefore, the first through electrode 15 can be used without any problems.

[0070] Second embodiment In the first embodiment, the element 7 was a piezoelectric element. Alternatively, the element 7 may be a pressure detection element or an inertial detection element. In this case, the through electrode may also have a structure including a gap 33. This can suppress problems caused by shrinkage of the through electrode. [Explanation of symbols]

[0071] 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...element, 11...common terminal as first electrode, 12...drive 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...drive connection terminal as second electrode, 33...gap, 36...second direction.

Claims

1. a first substrate having a first surface on which elements are arranged and first electrodes connected to the elements are arranged; 、 a second substrate having a second surface and a third surface, the second surface being disposed opposite the first surface; Equipped with The second substrate has a through hole extending from the second surface to the third surface at a position corresponding to the first electrode. It has a through hole through which a through electrode electrically connected to the first electrode is provided in the through hole; a gap filled with air is provided in a portion of the through electrode; The gap is surrounded by the through electrode, the first electrode, and the second substrate.

1. An electronic device comprising:

2. 10. The electronic device of claim 1, The ratio of the volume of the voids to the volume of the through holes is 1% or more and 50% or less. Electronic devices that are characteristic of

3. 10. The electronic device of claim 1, When the stacking direction of the first substrate and the second substrate is defined as a first direction, the first a ratio of the length of the void in the first direction to the length in the first direction is 25% or more and 95% or less; An electronic device comprising:

4. 4. The electronic device of claim 3, When a direction perpendicular to the first direction is defined as a second direction, the length of the through hole in the second direction is The ratio of the length of the void in the second direction to the total length of the void is 10% or more and 60% or less. Electronic device.

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

6. The electronic device according to any one of claims 1 to 5, The electronic device is characterized in that the through electrode is made of a resin containing a silver filler.

7. The electronic device according to any one of claims 1 to 6, a third substrate having a second electrode electrically connected to the through electrode and disposed opposite the third surface; An electronic device comprising:

8. 8. The electronic device of claim 7, the second substrate is adhesively fixed to the third substrate by a first fixing adhesive; The through electrode is bonded and fixed to the third substrate by a second fixing adhesive. An electronic device.

9. 9. The electronic device of claim 8, A direction perpendicular to the first direction is defined as a stacking direction of the first substrate and the second substrate. Let be the second direction, The second substrate is bonded to the third substrate at an end in the second direction by the first fixing adhesive. It is fastened and The through electrode is fixed at the end opposite to the second direction by the second fixing adhesive. An electronic device characterized by being adhesively fixed to three substrates.

10. a first substrate having a first surface on which elements are arranged and first electrodes connected to the elements are arranged; a second substrate having a second surface and a third surface, the second surface being disposed opposite the first surface; and The second substrate has a through hole extending from the second surface to the third surface at a position corresponding to the first electrode. forming a through hole through which the adhesively fixing the second substrate to the first substrate; filling the through holes with paste; and drying the paste filled in the through holes. By filling the through-hole with the paste, the paste, the first electrode, and A gap filled with air is formed between the second substrate and the first substrate. A method for manufacturing electronic devices.

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