JP5262946B2 - Electronic devices - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric device improved in connection reliability in electrical connection between a connection electrode of an electronic element layer and an external electrode of a holding member through a through electrode. <P>SOLUTION: This piezoelectric device is composed by joining an electronic element layer having an excitation electrode 26B to a joining object member having external electrodes 44A, 44B by applying a metal brazing material to joining surfaces thereof. In the piezoelectric device, the electronic element layer is formed with recessed parts 28A, 28B on connection electrodes 25A, 25B electrically connected to the excitation electrode 26B; and the joining object member is formed with through electrodes electrically connected to the external electrodes 44A, 44B, and fitting to the recessed parts 28A, 28B by being projected to the joining surface to be electrically connected to the connection electrodes. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

In particular, the present invention has high reliability against thermal shock such as external stress and heat cycle caused by solder reflow, and in electrical connection via a through electrode between the terminal electrode of the intermediate layer and the external terminal of the holding member. The present invention relates to an electronic device that improves connection reliability and a method for manufacturing the same.

As electronic devices, communication devices, and the like are miniaturized, there are piezoelectric devices disclosed in Patent Documents 1 to 4 in which a plurality of substrates are stacked in order to cope with the miniaturization.
As shown in FIG. 13, the piezoelectric oscillator disclosed in Patent Document 1 includes a piezoelectric vibrator 80 having a pair of vibrating electrodes 81 a and 81 b and an insulating support plate 82 joined to both main surfaces of the piezoelectric vibrator 80. And two lead terminals 84a and 84b provided on the bottom surface of the insulating support plate 82 and the thickness direction of the insulating support plate 82 at the time of three-layer bonding via the insulating adhesive 85. The projecting portions 88a and 88b of the lead terminals 84a and 84b and the extraction electrodes 89a and 89b are connected by the conductive members 87a and 87b in the connection holes 86a and 86b formed in the above. Thereby, the lead terminals 84a and 84b and the vibration electrodes 81a and 81b are electrically connected.

  As shown in FIG. 14, the thin crystal resonator disclosed in Patent Document 2 includes a three-layer All Quartz Package laminated by direct bonding using a siloxane bond, and conductive adhesives 91a, such as solder, in the through holes 90a, 90b. 91b is embedded, and the through-holes 90a and 90b are sealed at the same time as connecting to the extraction electrodes 93a and 93b of the crystal piece 92. It is disclosed to form on the side surface and both main surfaces.

  The crystal resonator disclosed in Patent Document 3 is a three-layer All Quartz Package laminated by direct bonding as shown in FIG. As shown in (b), the metal powder 103 is sprayed on the through-hole 102 formed in advance in the sheet-like wafer 101 for the base of the crystal unit 100 formed in a wafer shape, and the metal powder 103 is inserted into the through-hole 102. In addition to filling the gap between the surface of the crystal resonator element 104 and the through-hole 102 while being deposited inside, the metal powder 103 is deposited inside the through-hole 102 so that the crystal resonator element 104 inside the crystal resonator 100 It is disclosed that the electric conduction path 105 is formed by packing and closely contacting the surface of the base sheet-like wafer 101 through the inside of the through hole 102. When the metal powder 103 is sprayed on the through hole 102, the metal powder 103 is melted by frictional heat generated by friction with the inner wall of the through hole 102, filling the gap between the surface of the crystal vibrating element 104 and the through hole 102. Then, the metal powder 103 is closely attached to the inside of the through hole 102 and deposited, and the metal powder 103 is packed from the quartz vibrating element 104 inside the quartz crystal resonator 100 to the surface of the base sheet-like wafer 102 through the inside of the through hole 102. .

  As the metal powder 103, powdery aluminum (Al), copper (Cu), silver (Ag), gold (Au), etc. having a particle diameter of about 10 micrometers can be used, and the size of the through hole 102 is as follows. The diameter is as small as about 20 to 200 micrometers, the external terminal shape is not substantially rectangular, and the through hole 102 as shown in FIG. There is no disclosure.

  Similarly, in Patent Document 4, in a three-layer All Quartz Package laminated by direct bonding, as shown in FIG. 15C, a sheet-like wafer for a base of a crystal unit 100 in which metal foil fine particles are formed in a wafer shape 101 is irradiated with a laser beam 110 emitted from the laser irradiation device 108 onto a metal foil 109 disposed between the laser irradiation device 108 and the through hole 102 of the base sheet-like wafer 101. The metal foil fine particles 111 are deposited in the through-hole 102, and the gap between the surface of the crystal resonator element 104 and the through-hole 102 is filled with the metal foil fine particles 111, and then the metal foil fine particles 111 are filled. Foil fine particles are deposited inside the through-hole 102, and pass through the inside of the through-hole 102 from the crystal resonator element 104 inside the crystal unit 100. A method for forming an electrical conduction path is disclosed in which metal foil fine particles 111 are deposited up to the surface of the base sheet-like wafer 101 to form an electrical conduction path 107.

JP 2001-102900 A JP 2000-269775 A JP 2008-113378 A JP 2008-167302 A

  However, Patent Document 1 has a laminated structure in which an insulating support plate 82 and a protective plate 83 are bonded to both main surfaces of a piezoelectric vibrator 80 via an insulating adhesive 85, and the conductive member 87 has lead electrodes 89 a and 89 b. Since the vibration electrode 81 and the lead terminal 84 are electrically connected by contacting with each other, there is a problem that connection reliability is poor against the influence of external stress and thermal shock.

  Further, in Patent Documents 2 to 4, there are originally gaps (voids) between the through holes and the routing electrodes, and the brazing material (metal fine particles) has a large contact area due to the surface tension. As a result, the brazing material does not reach the lead electrode, and as a result, there is a problem that electrical connection between the brazing material in the through hole and the lead electrode may not be secured.

Accordingly, the present invention has been made in view of the above-described problems of the prior art, and has high reliability against external stress caused by solder reflow, thermal shock such as heat cycle, and the like, and terminal electrodes and holding members of the intermediate layer It is an object of the present invention to provide an electronic device having improved connection reliability in electrical connection between the external terminal and a through electrode, and a method for manufacturing the same.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
An electronic device according to an embodiment of the present invention includes an electronic element layer including a connection electrode, an external electrode, and a joining surface of the electronic element layer and a metal brazing material in a state of overlapping with the connection electrode The electronic element layer has a recess on the surface of the bonded member on the connection electrode, and the bonded member overlaps the connection electrode. An electrode that fits into the recess at a position that is electrically connected to the external electrode and the connection electrode, and the member to be joined is connected to the external electrode at a position that overlaps the connection electrode The electrode having an electrically connected wiring pattern and fitted in the recess is a bump disposed on the wiring pattern.
In an electronic device according to another embodiment of the present invention, the electrode fitted in the recess is tapered from the joining surface side with the electronic element layer toward the back surface of the member to be joined. It is characterized by that.
An electronic device according to another embodiment of the present invention is characterized in that the concave portion has a tapered shape whose diameter decreases from the opening toward the bottom surface.
[Application Example 1] An electronic element layer having a connection electrode and an external electrode, and being fixed to the joint surface of the electronic element layer and a metal brazing material in a state of being overlapped with the connection electrode A member to be joined, and the electronic element layer has a recess in the connection electrode on the surface of the member to be joined, and the member to be joined is fitted in the recess at a position overlapping the connection electrode. An electronic device comprising: an electrode that electrically connects the external electrode and the connection electrode.

According to this, when the bonding of the electronic element layer and the workpieces, by mating the tip of the recess and the electrodes, since the connection electrodes and the external electrodes can be electrically connected, Ya external stress by solder reflow It has high reliability against thermal shock such as heat cycle, and can improve the reliability of electrical connection.

Application Example 2 The electronic device according to Application Example 1, wherein the electrode fitted in the recess is formed by melting a metal ball.
According to this, when the metal ball is dropped into the sealing hole, the metal ball can be fixed by the recess located on the bottom surface of the sealing hole. Therefore, the metal ball does not roll inside the sealing hole, and the irradiation positioning of the metal ball by laser irradiation can be easily performed.

Application Example 3] The electrode that is fitted in the recess, through the bonded members facing the recess, Application Example 1, which is a convex electrode that protrudes into the concave side The electronic device according to.
When the electronic element layer and the member to be bonded are bonded, the connection electrode and the external electrode can be electrically connected by fitting the tip of the electrode into the recess. Thereby, the reliability of electrical connection can be improved.

Application Example 4 The member to be joined has a wiring pattern electrically connected to the external electrode at a position overlapping the connection electrode, and the electrode fitted in the recess is electronic device according to application example 1, which is a bump disposed on Sharing, ABS line pattern.
When the electronic element layer and the member to be bonded are bonded, the connection electrode and the external electrode can be electrically connected by fitting the tip of the bump into the recess. Further, it is possible to prevent the electrode from falling off from the bonded member when the bump and the recess are fitted.

Application Example 5] The electrode that is fitted in the recess, applications wherein the a Te over path shape toward the rear surface of the members to be bonded from the bonding surface of the electronic element layer The electronic device according to any one of 1 to 4.
According to this, it is possible to prevent the electrode from dropping from the member to be joined when the electrode and the recess are fitted.

Application Example 6 The electronic device according to any one of Application Examples 3 to 5, wherein the concave portion has a tapered shape with a diameter decreasing from the opening toward the bottom surface.
According to this, since the contact area between the recess and the electrode can be increased, the electrical resistivity is lowered. Therefore, the CI value can be improved.

Application Example 7 An electronic element layer including a connection electrode having a recess, and an external electrode and a member to be bonded that is bonded to a bonding surface of the electronic element layer . a method of manufacturing an electronic device, wherein the forming the electrode protruding to the bonding surface side of the material to be joined, the said recess of the electronic element layer, by fitting the electrodes the projecting, the said electronic device layer to be A method for manufacturing an electronic device, wherein the bonding member includes a step of forming a laminate.

According to this, when the electronic element layer and the member to be joined are joined, the connection electrode and the external electrode can be electrically connected by fitting the tip of the electrode into the recess, so that the reliability of electrical connection It is possible to manufacture an electronic device with improved resistance.

It is the disassembled perspective view which looked at the piezoelectric vibrator of Example 1 which is one example of the electronic device concerning the present invention from the slanting upper part of the 1st substrate. It is the disassembled perspective view seen from the slanting lower part of the 2nd board | substrate of the piezoelectric vibrator of Example 1 which is one Example of the electronic device which concerns on this invention. 2 is a cross-sectional view of the piezoelectric vibrator of Example 1. FIG. It is a manufacturing-process figure of a 1st board | substrate. It is a manufacturing-process figure of a 2nd board | substrate. It is a manufacturing process figure of a vibrating body board. 6 is a manufacturing process diagram of a through electrode of the piezoelectric vibrator of Example 1. FIG. 6 is a cross-sectional view of a piezoelectric vibrator of Example 2. FIG. 6 is a manufacturing process diagram of a second substrate of Example 2. FIG. It is the elements on larger scale of the joining process of a penetration electrode and a recessed part. 6 is a cross-sectional view of a piezoelectric vibrator of Example 3. FIG. FIG. 12 is a manufacturing process diagram for the second substrate of Example 3. It is explanatory drawing of the conventional piezoelectric oscillator. It is explanatory drawing of the conventional thin crystal oscillator. It is explanatory drawing of the conventional crystal oscillator.

Embodiments of an electronic device and a manufacturing method thereof according to the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is an exploded perspective view of a piezoelectric vibrator according to a first embodiment, which is an embodiment of an electronic device according to the present invention, viewed obliquely from above a first substrate. FIG. 2 is an exploded perspective view of the piezoelectric vibrator as viewed from obliquely below the second substrate. FIG. 3 is a cross-sectional view of the piezoelectric vibrator of the first embodiment. 1 to 3 all show a piezoelectric vibrator excluding a through electrode.

The piezoelectric vibrator 10 according to the present invention includes a vibrating body substrate 20, a first substrate 30, and a second substrate 40.
The vibrating body substrate 20 serving as an electronic element layer includes a vibrating body 21 and a frame body 22 that surrounds the vibrating body 21 with a predetermined distance from the outer periphery of the vibrating body 21. The vibrating body 21 and the frame body 22 are integrally formed via connecting portions 23A and 23B. Note that the vibrating body 21 of the present embodiment is formed thinner than the frame body 22, and the connecting portions 23A and 23B are formed in a tapered shape. A projecting portion 24 is formed on the frame located diagonally to the connecting portion 23A. A pair of connection electrodes 25 </ b> A and 25 </ b> B are formed on the back surface (second substrate 40 side) of the connecting portion 23 </ b> A and the protruding portion 24.

  The connection electrodes 25A and 25B have recesses 28A and 28B formed in the center. The recesses 28A and 28B are recessed from the surface of the connection electrodes 25A and 25B, and are formed in a tapered shape (circular shape) that decreases in diameter from the opening toward the bottom surface. The recess 28 is formed with a metal layer having a multilayer structure in which a Cr layer is used as a base on the inner wall surface when a connection electrode 25 described later is formed, and an Au layer is laminated thereon. Thus, the inner wall surface of the recess 28 is electrically connected to the connection electrodes 25A and 25B.

  A pair of excitation electrodes 26 </ b> A and 26 </ b> B are formed on the front and back surfaces of the vibrating body 21 so as to face each other. The excitation electrodes 26A and 26B are electrically connected to connection electrodes 25A and 25B formed diagonally on the back surface of the vibrator substrate 20 through the routing electrodes 27A and 27B, respectively.

  The vibrator substrate 20 according to the embodiment will be described by using a flat AT-cut quartz substrate as an example, but the vibrator substrate 20 may be made of lithium tantalate, lithium niobate, lead zirconate titanate, etc. in addition to quartz. It is possible to apply a piezoelectric material, a semiconductor material such as a silicon semiconductor, or other insulator materials.

  For the first and second substrates 30 and 40 to be bonded members, quartz, glass, or a ceramic substrate can be used as a material. The first and second substrates 30 and 40 are preferably made of the same material as that of the vibrator substrate 20 in order to avoid thermal distortion and internal stress due to a difference in thermal expansion coefficient.

  The first substrate 30 is a flat substrate that covers the upper surface of the vibrating body substrate 20. The second substrate 40 is a flat substrate that supports the lower surface of the vibrator substrate 20. In the second substrate 40, sealing holes 42 </ b> A and 42 </ b> B are formed at positions facing the connection electrodes 25 </ b> A and 25 formed on the lower surface of the vibrator substrate 20. In the sealing holes 42A and 42B, a metal layer having a multilayer structure in which a Cr layer is used as a base on the inner wall surface and an Au layer is laminated thereon is formed. External electrodes 44 </ b> A and 44 </ b> B are formed on the lower surface of the second substrate 40. The external electrodes 44A and 44B are electrodes used to electrically connect the piezoelectric vibrator 10 to an external device. The sealing holes 42 </ b> A and 42 </ b> B are formed in a tapered shape (circular shape) having a large diameter from the joint surface with the vibrator substrate 20 toward the external electrode 44 side. In the sealing holes 42A and 42B, the eutectic metal balls 70 are dropped and melted to be electrically connected to the connection electrodes 25A and 25B.

  The first bonding portion 50 is a eutectic alloy layer formed between the vibrating body substrate 20 and the first substrate 30. The second joint 60 is a layer of a eutectic alloy that is the same quality as the first joint 50 formed between the vibrating body substrate 20 and the second substrate 40.

The first bonding portion 50 and the second bonding portion 60 are formed of a bonding metal layer in order to form an Au—In eutectic alloy using a liquid phase diffusion bonding method (hereinafter referred to as TLP (Transient Liquid Phase) bonding). As an Au layer constituting metal metallization, at least one of the joint portions has a laminated structure in which an In layer serving as a brazing material is laminated on the surface of the Au layer. An Au-In eutectic alloy is formed by heating In at approximately 156 degrees or more, which is the melting point of In, causing In to melt and diffusing the In into Au to cause a eutectic reaction. Can do. The eutectic point of the Au—In eutectic alloy formed at this time is about 280 degrees.
In addition, in the said 1st junction part 50 and the 2nd junction part 60 joined by the said TLP joining, what is necessary is just a joining performed by not only Au-In joining but crystal alpha-beta transition temperature 573 degrees C or less, and insert metal In addition, Sn or SnIn and the bonding metal layer may be Cu. Further, the bonding metal layer may be directly formed of eutectic metal such as Au-20Sn (melting point: 280 degrees), Au-12Ge (melting point: 375 degrees), Au-6Si (melting point: 370 degrees).

  Next, a method for manufacturing a piezoelectric vibrator having the above configuration will be described. FIG. 4 is a manufacturing process diagram of the first substrate. FIG. 5 is a manufacturing process diagram of the second substrate. FIG. 6 is a manufacturing process diagram of the vibrator substrate. FIG. 7 is a manufacturing process diagram of the through electrode of the piezoelectric vibrator of the first embodiment.

  In the first substrate 30 shown in FIG. 4A, a frame-shaped first bonding portion 50 made of an Au—In eutectic alloy is formed on the bonding surface with the vibrating body substrate 20 on the quartz substrate. First, in order to improve the adhesion of the Au layer 32, as shown in FIG. 4B, an adhesion layer 31 made of a Cr or Ti film having high adhesion to the quartz substrate is formed on the substrate 30, and then the bonding metal. The Au layer 32 is formed by vapor deposition, sputtering, plating, or the like. Here, in order to prevent diffusion between the adhesion layer 31 and the bonding metal layer, a Pt or Pd film is formed between the adhesion layer 31 and the bonding metal layer as a diffusion prevention layer to improve bonding reliability. be able to. Finally, an In layer 33 of low melting point metal is formed on the surface of the Au layer 32 formed on the second substrate 30.

  In the second substrate 40 shown in FIG. 5A, the sealing holes 42A and 42B are formed by using a photolithography technique and an etching technique or a sand blasting technique (FIG. 5B). In addition, a base Cr layer is formed on the inner wall surfaces of the formed sealing holes 42A and 42B, and an Au layer 43 is formed on the upper layer by vapor deposition or sputtering (FIG. 5C). Further, as shown in FIG. 5D, a second bonding portion 60 made of an Au—In eutectic alloy is formed on the bonding surface with the vibrating body substrate 20. First, in order to improve the adhesion of the Au layer 42, an adhesion layer 46 made of a Cr or Ti film having high adhesion to the quartz substrate is formed on the second substrate 40, and thereafter, Cr or Ti having high adhesion to Au is formed. An Au layer 47 is formed on the adhesion layer 46 made of a film by vapor deposition or sputtering. Here, in order to prevent diffusion between the adhesion layer 46 and the bonding metal layer, a Pt or Pd film is formed as an anti-diffusion layer between the adhesion layer 46 and the bonding metal layer to improve bonding reliability. be able to. Finally, an In layer 48 of low melting point metal is formed on the surface of the Au layer 47 formed on the substrate.

  In the vibrating body substrate 20 shown in FIG. 6A, a vibrating body having a reverse mesa structure and recesses 28A and 28B are formed by using a photolithography technique and an etching technique or a sandblasting technique (FIG. 6B). Further, the outer shape of the vibrating body 21 is formed by using a photolithography technique and an etching technique or a sand blasting method (FIG. 6C). The recess 28 may be formed at the same time as the outer shape of the vibrating body 21 is formed. Next, the excitation electrode 26, the routing electrode 27, the connection electrode 25, and the Au layer 29 of the Au—In eutectic alloy are integrally formed by vapor deposition or sputtering (FIG. 6D). Then, frequency adjustment is performed on the formed excitation electrode 26A while monitoring by reducing the metal layer by ion etching or adding mass by vapor deposition (FIG. 6E).

  Next, the vibration substrate 20 and the first and second substrates 30 and 40 are bonded by TLP bonding. Specifically, a laminated body is formed by overlapping the bonding surfaces of the substrates. Then, by heating and pressing at a temperature equal to or higher than the melting point of the In layer (about 156 degrees), for example, about 200 degrees, the In layer between the Au layers is melted and the eutectic reaction is caused by diffusing In into the Au layer. Then, Au—In which is a eutectic alloy is formed.

Then, the through hole of the piezoelectric vibrator 10 is sealed. Specifically, as shown in FIG. 7A, eutectic metal balls 70 made of Au—Ge or the like are dropped into the sealing holes 42 </ b> A and 42 </ b> B of the second substrate 40 in a vacuum sealing or an inert gas atmosphere, for example. At this time, the eutectic metal ball 70 is fixed on the recess 28 and does not roll in the sealing holes 42A and 42B. Next, the eutectic metal balls 70 in the sealing holes 42A and 42B are irradiated with a laser to be locally heated and melted. As shown in FIG. 7B, the melted eutectic machine metal ball 70 forms a through electrode in the recess 28 and the sealing hole 42 and is electrically connected to the connection electrode 25. Since the eutectic metal ball 70 melts instantaneously, the Au—In eutectic alloy does not spread around the electrode 27 and the excitation electrode 26 and does not affect the oscillation frequency.
Further, external electrodes 44A and 44B are formed on the outer surface of the second substrate 40 by vapor deposition or sputtering so as to include sealing holes 42A and 42B (so as to be electrically connected to the sealing holes 42). ing.

  According to the piezoelectric vibrator of Example 1 as described above, the eutectic metal ball is melted to be a through electrode, and the connection electrode and the external electrode are electrically connected by fitting the recess and the tip of the through electrode. Therefore, it has high reliability against external stress due to solder reflow and thermal shock such as heat cycle, and the reliability of electrical connection can be improved.

  Next, an embodiment of the piezoelectric vibrator of Example 2 will be described below. FIG. 8 is an explanatory diagram of the piezoelectric vibrator 10a according to the second embodiment. As shown in FIG. 8A, the difference in configuration between the piezoelectric vibrator 10a of the second embodiment and the piezoelectric vibrator 10 of the first embodiment is a through electrode 49 of the second substrate 400. The first substrate 10 and the electronic element layer 20 are the same as those in the first embodiment, and detailed description thereof is omitted. As shown in FIG. 8B, the second substrate 400 is formed with a through electrode 49 that penetrates a conductive material.

  A method for manufacturing the second substrate 400 of Example 2 will be described below. FIG. 9 is an explanatory diagram of the manufacturing process of the second substrate of the second embodiment. As shown in FIG. 9B, the second substrate 400 shown in FIG. 9A has through holes 45A and 45B formed using a photolithography technique and an etching technique or a sand blasting technique. The through hole 45 is formed in a tapered shape (circular shape) having a diameter that decreases from the joint surface toward the back surface.

  Then, an underlying Cr layer is formed on the inner wall surfaces of the formed through holes 45A and 45B, and an Au layer is formed thereon by vapor deposition or sputtering (FIG. 9C). The conductive material 41 to be the through electrode 49 is press-fitted and embedded in the through holes 45A and 45B. Since the bonding surface of the through electrode 49 formed by embedding the conductive material 41 is slightly convex, the bonding surface is polished flat. Thereafter, the external electrodes 44A and 44B are formed by vapor deposition or sputtering (FIG. 9E). Next, only the one surface on the bonding surface side of the second substrate 400 is thinly formed by an etching technique, and the bonding surface of the through electrode 49 protrudes from the surface of the second substrate 400 (FIG. 9F). Next, as shown in FIG. 9G, a base adhesion layer 46 is formed on the upper surface of the through electrode 49 and the bonding surface of the second substrate 400, and an Au layer 47 is formed thereon by vapor deposition or sputtering. Further, a low melting point metal In layer 48 is formed on the surface of the Au layer 47 formed on the substrate (FIG. 9 (h)).

  For joining the vibrating body substrate 20 and the first and second substrates 30 and 400, first, the joining surfaces of the vibrating body substrate 20 and the first and second substrates 30 and 400 are overlapped to form a laminated body. FIG. 10 is a partially enlarged view of the joining process of the through electrode 49 and the recess 28. As shown in FIG. 10A, since the bottom surface area of the recess 28 is smaller (or substantially the same) than the tip area of the through electrode 49, positioning (alignment work) is facilitated. When the second substrate 400 and the vibrating body substrate 20 are laminated, the tip of the through electrode 49 comes into contact with the bottom surface of the recess 28, and when further pressed, the tip of the through electrode 49 is crushed by the bottom surface of the recess 28. The tip of the flange is fitted into a flange shape.

  After the lamination, heating and pressing are performed at a temperature equal to or higher than the melting point (about 156 degrees) of the In layer, for example, about 200 degrees. As a result, the In layer between the Au layers of the first or second substrate 30 and 400 and the vibrator substrate 20 is melted to cause In to diffuse into the Au layer, thereby causing a eutectic reaction. -In is formed.

  According to the piezoelectric vibrator of the second embodiment, when the electronic element layer and the member to be joined are joined, the connection electrode and the external electrode are electrically connected by fitting the tip of the through electrode into the recess. Can do. Thereby, the reliability of electrical connection can be improved. Moreover, since the contact area of a recessed part and a penetration electrode can be enlarged, an electrical resistivity falls. Therefore, the CI value can be improved.

  Next, an embodiment of the piezoelectric vibrator of Example 3 will be described below. FIG. 11 is a cross-sectional view of the piezoelectric vibrator 10b according to the third embodiment. As shown in FIG. 11A, the difference in configuration between the piezoelectric vibrator 10b of the third embodiment and the piezoelectric vibrator 10 of the first embodiment is a through electrode of the second substrate 410. The first substrate 30 and the electronic element layer 20 are the same as those in the first embodiment, and detailed description thereof is omitted. As shown in FIG. 11B, the second substrate 410 has bumps 54A and 54b formed on the wiring pattern on the bonding surface as through electrodes.

  A method for manufacturing the second substrate 410 of Example 3 will be described below. FIG. 12 is an explanatory diagram of the manufacturing process of the second substrate of the third embodiment. In the second substrate 410 shown in FIG. 12A, through holes 45A and 45B are formed by using a photolithography technique and an etching technique or a sand blasting technique as shown in FIG. 12B. The through holes 45 </ b> A and 45 </ b> B are formed in a tapered shape (circular shape) having a diameter that decreases from the joint surface toward the external electrode side.

  Then, an underlying Cr layer is formed on the inner wall surfaces of the formed through-holes 45A and 45B, and an Au layer is formed thereon by vapor deposition or sputtering (FIG. 12C). The conductive material 41 is press-fitted and embedded in the through holes 45A and 45B. Thereafter, external electrodes 44A and 44B are formed on the back surface by vapor deposition or sputtering (FIG. 12E). A wiring pattern 52 is formed on the bonding surface. One end of the wiring pattern 52 is formed so as to cover the upper surface of the conductive material 41, and the other end is formed by vapor deposition or sputtering so as to face the recess. Bumps 54A and 54B made of Au or the like are formed on the wiring patterns 52A and 52B at positions facing the recesses (FIG. 12 (f)). Next, as shown in FIG. 12G, an adhesion layer 46 made of a base Cr or Ti film is deposited on the tips (bonding surfaces) of the bumps 54A and 54B and the bonding surface of the second substrate, and an Au layer 47 is deposited thereon. Or it forms by the sputtering method etc. A low melting point metal In layer 48 is formed on the surface of the Au layer 47 formed on the substrate (FIG. 12 (h)).

  In joining the vibrating body substrate 20 and the first and second substrates 30 and 410, first, the joining surfaces of the vibrating body substrate 20 and the first and second substrates 30 and 410 are overlapped to form a laminated body. Since the bottom surface area of the recess 28 is formed smaller (or substantially the same) as the tip end area of the bump 54 serving as a through electrode, positioning is easy. When the second substrate 410 and the vibrating body substrate 20 are laminated, the tip of the bump 54 comes into contact with the bottom surface of the recess 28, and further pressing continues the tip of the bump 54 of the recess 28 like the through electrode 49 shown in FIG. The bumps 54 are crushed by the bottom surface, and the ends of the bumps 54 are fitted into a flange shape.

  After the lamination, heating and pressing are performed at a temperature equal to or higher than the melting point (about 156 degrees) of the In layer, for example, about 200 degrees. As a result, the In layer between the Au layer of the first or second substrate and the diaphragm is melted, causing In to diffuse into the Au layer, thereby causing a eutectic reaction and forming Au-In as a eutectic alloy. The

  According to the piezoelectric vibrator of the third embodiment, when the electronic element layer and the member to be joined are joined, the connection electrode and the external electrode are electrically connected by fitting the tip of the through electrode into the recess. Can do. Thereby, the reliability of electrical connection can be improved. Further, it is possible to prevent the through electrode from falling off the member to be joined when the bump and the recess are fitted.

  As described above, the electronic device according to the present invention has been described using a piezoelectric vibrator having a three-layer structure in which the upper and lower surfaces of the vibrator substrate 20 are sandwiched between the first substrate 30 and the second substrate 40, respectively. In addition, the present invention can be applied to SAW vibrators, pressure sensors, and the like.

10, 10a, 10b ......... Piezoelectric vibrator, 20, 200 ......... Vibrating body substrate, 21 ......... Vibrating body, 22 ......... Frame body, 23 ......... Connecting portion, 24 ......... Protruding portion, 25... Connection electrode, 26... Excitation electrode, 27... Leading electrode, 28... Recess, 29... Au layer, 30. ......... Au layer, 33 ......... In layer, 40, 400, 410 ......... second substrate, 41 ......... conductive material, 42 ......... sealing hole, 44 ......... external electrode, 45 ... ...... Through hole 46... Adhesion layer 47... Au layer 48... In layer 49... Through electrode 50... First junction 52. ......... Bump, 60 ......... Second joint, 70 ......... Eutectic metal ball, 80 ......... Piezoelectric vibrator, 81 ......... Vibrating electrode, 82 ......... Insulation Support plate 83... Protection plate 84... Lead terminal 85... Insulating adhesive 86... Connection hole 87 87 Conductive member 88 Projecting portion 89. ... Extraction electrode, 90 ......... Through hole, 91 ... Conductive adhesive, 92 ......... Crystal piece, 93 ...... Extraction electrode, 94 ...... Mounting electrode, 100 ... Crystal oscillator, 101 ......... Sheet-like wafer for base, 102 ......... Through hole, 103 ......... Metal powder, 104 ...... Quartz vibrating element, 105 ...... Electrical conduction path, 107 ...... Electrical conduction path, 108 ... Laser irradiation device, 109 ... Metal foil, 111 Metal foil particles.

Claims (3)

An electronic element layer comprising a connection electrode;
An external electrode, and a member to be bonded that is fixed via a metal brazing material and a bonding surface of the electronic element layer in a state of overlapping with the connection electrode,
The electronic element layer has a concave portion on the surface to be bonded to the connection electrode,
The member to be joined includes an electrode that fits into the concave portion at a position overlapping the connection electrode, and electrically connects the external electrode and the connection electrode ;
The member to be joined has a wiring pattern electrically connected to the external electrode at a position overlapping the connection electrode,
The electronic device , wherein the electrode fitted in the recess is a bump disposed on the wiring pattern . 2. The electronic device according to claim 1 , wherein the electrode fitted in the concave portion is tapered from the side of the joint surface with the electronic element layer toward the back surface of the member to be joined . The electronic device according to claim 1, wherein the concave portion has a tapered shape having a small diameter from the opening toward the bottom surface .