JP2014143558A - Method of manufacturing electronic device, electronic device, and oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an electronic device with a through electrode prevented from corroding, in a short time.SOLUTION: A method of manufacturing an electronic device 1 includes: a through electrode forming step S1 of forming a through electrode 3 in an insulating base substrate 2; an electronic element mounting step S2 of mounting an electronic element 5 on one surface US of the base substrate 2; a lid placing step S3 of joining a lid 6 accommodating the electronic element 5 to the base substrate 2; a conductive film forming step S4 of forming a conductive film 4 on the other surface LS of the base substrate 2 and on an end face M of the through electrode 3 exposed to that surface; an electroplating film forming step S5 of forming an electroplating film 11 on a surface of the conductive film 4 by electroplating; and an external electrode forming step S6 of patterning the electroplating film 11 and the conductive film 4 to form an external electrode 13 on the end face M of the through electrode 3 and around the end face M.

Description

  The present invention relates to an electronic device manufacturing method in which an electronic element such as a crystal resonator is housed in a package, an electronic device, and an oscillator using the electronic device.

  2. Description of the Related Art Conventionally, surface-mounted electronic devices are often used for mobile phones and portable information terminals. Among these, a quartz resonator, a MEMS, a gyro, an acceleration sensor, and the like have a hollow cavity formed inside a package, and an electronic element such as a quartz resonator or MEMS is enclosed in the cavity. A glass material is used as the package. For example, an electronic device is mounted on a base substrate, and a glass lid is bonded thereon by anodic bonding to seal the electronic device. Anodic bonding between glasses has the advantage of being highly airtight and inexpensive.

  FIG. 7 is a cross-sectional view of this type of electronic device (FIG. 1 of Patent Document 1). The electronic device 101 includes a base 110, an electronic component 140 mounted on the base 110, and a cap 150 that houses the electronic component 140 and is joined to the base 110. The base 110 has a through electrode 121 that penetrates in the plate thickness direction, a first metal film 122 that is electrically connected to the through electrode 121, and a circuit pattern 130 that electrically connects the through electrode 121 and the electronic component 140. And the 2nd metal film 123 is formed. An external electrode 160 made of a metal film is formed outside the first metal film 122.

  Here, an iron-nickel alloy is used for the through electrode 121. As the first metal film 122, gold formed by electroless plating is used. Further, a low-melting glass (not shown) is used between the through electrode 121 and the base 110, and the airtightness is improved by heat welding. When a low melting point glass is used for thermal welding to improve the airtightness between the through electrode 121 and the base 110, an oxide film is formed on the end face of the through electrode 121, and the conductivity between the other metal is reduced. Decreases. Therefore, after removing the oxide film formed during the thermal welding of the through electrode 121, the first metal film 122 and the second metal film 123 are formed on the end face of the through electrode 121 to prevent the through electrode 121 from being oxidized. ing.

JP 2011-155506 A

  An iron-nickel alloy is used as the through electrode 121, and a gold thin film is used as the first metal film 122 for preventing oxidation of the through electrode 121. Since there is a large difference in ionization tendency between the iron-nickel alloy and gold, if moisture or the like adheres between the through electrode 121 and the first metal film 122, the through electrode 121 is corroded by the battery effect, and the conductivity is lowered. Cause. In Patent Document 1, a low-melting glass is used between the through electrode 121 and the base 110, and a gold thin film of the first metal film 122 is formed on the end surface of the through electrode 121 by an electroless plating method. Since it is difficult to form a gold thin film by electroless plating on the low-melting glass, the boundary between the through electrode 121 and the first metal film 122 is exposed and corrosion tends to proceed.

  Further, when the first metal film 122 is deposited by the electroless plating method, for example, it takes a long time to form a metal film having a thickness of 1 μm or more, and the mass productivity is low. Even if an electroplating method with a high deposition rate is used instead of the electroless plating method, the through electrodes are formed in an island shape in the insulator, which makes it difficult to conduct each through electrode. Productivity decreases.

  The electronic device manufacturing method of the present invention includes a through electrode forming step of forming a through electrode on an insulating base substrate, an electronic element mounting step of mounting an electronic element on one surface of the base substrate, and the electronic device. A lid installation step for joining a lid to be accommodated to the base substrate; a conductive film formation step for forming a conductive film on the other surface of the base substrate and an end surface of the through electrode exposed on the other surface; An electrolytic plating film forming step of forming an electrolytic plating film on the surface of the conductive film by an electrolytic plating method; and patterning the electrolytic plating film and the conductive film to form external electrodes around the end surfaces of the through electrodes and the end surfaces And forming an external electrode to be formed.

  In addition, the external electrode forming step is performed after the electronic element mounting step and the lid installation step.

  Further, a metal film forming step of forming a metal film on the surface of the electrolytic plating film is provided after the electrolytic plating film forming step.

  The through electrode is an iron-nickel alloy.

  The electrolytic plating film is a nickel film or a copper film.

  The metal film is a gold thin film.

  The electrolytic plating film has a thickness of 1 μm to 10 μm.

  The electronic element is a crystal vibrating piece.

  An electronic device according to the present invention includes an insulating base substrate on which a plurality of through electrodes are formed, an electronic element mounted on one surface of the base substrate, and the electronic element is accommodated and bonded to the base substrate. An external electrode is formed on an end surface of the through electrode exposed on the other surface of the base substrate, and on the other surface around the end surface, and the external electrode includes a conductive film and the An electrolytic plating film formed by an electrolytic plating method is provided on the conductive film.

  The through electrode is made of an iron-nickel alloy, the conductive film is made of a metal film, and the electrolytic plating film is made of nickel or copper.

  An oscillator according to the present invention includes the electronic device described above and a drive circuit that supplies a drive signal to the electronic device.

  The electronic device manufacturing method of the present invention includes a through electrode forming step of forming a through electrode on an insulating base substrate, an electronic element mounting step of mounting an electronic element on one surface of the base substrate, and housing the electronic device. A lid installation step for joining the lid to the base substrate, a conductive film forming step for forming a conductive film on the other surface of the base substrate, and an end face of the through electrode exposed on the surface, and electroplating on the surface of the conductive film An electrolytic plating film forming step of forming an electrolytic plating film by a method, and an external electrode forming step of patterning the electrolytic plating film and the conductive film to form an external electrode around the end face of the through electrode and the end face. . Thereby, the electronic device which prevented the penetration electrode from corroding can be manufactured in a short time.

It is a cross-sectional schematic diagram of the electronic device which concerns on 1st embodiment of this invention. It is process drawing showing the manufacturing method of the electronic device which concerns on 2nd embodiment of this invention. It is explanatory drawing of the manufacturing process of the electronic device which concerns on 2nd embodiment of this invention. It is explanatory drawing of the manufacturing process of the electronic device which concerns on 2nd embodiment of this invention. It is process drawing showing the manufacturing method of the electronic device which concerns on 3rd embodiment of this invention. It is a top surface schematic diagram of the oscillator concerning a 4th embodiment of the present invention. It is sectional drawing of a conventionally well-known electronic device.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of an electronic device 1 according to the first embodiment of the present invention. The electronic device 1 includes a base substrate 2, a lid body 6 bonded on the base substrate 2, and an electronic element 5 accommodated therein. The base substrate 2 has insulating properties and includes a plurality of through electrodes 3 that penetrate from one surface US to the other surface LS. A wiring electrode 8 is formed on one surface US of the base substrate 2 so as to cover the end face of the through electrode 3, and the electronic element 5 is mounted on the wiring electrode 8 via a metal bump 10. The lid 6 has a recess in the center, and the electronic element 5 is accommodated in the recess and is bonded to one surface US of the base substrate 2 via a bonding material 9. The base substrate 2 further includes an end surface M of the through electrode 3 exposed on the other surface LS of the base substrate 2 and an external electrode 13 formed on the other surface LS around the end surface M. The external electrode 13 has a laminated structure in which the conductive film 4 and the electrolytic plating film 11 formed by an electrolytic plating method are laminated.

  Thus, the end surface M exposed to the other surface LS of the through electrode 3 formed on the base substrate 2 and the other surface LS near the periphery thereof are covered with the conductive film 4 and the electrolytic plating film 11. Therefore, the through electrode 3 does not come into contact with moisture or the like, and corrosion is prevented. Further, since the electrolytic plating film 11 can be simultaneously formed on the end surfaces M of the plurality of through electrodes 3 by electrolytic plating, the film formation time is shortened. A metal thin film for preventing oxidation can be formed on the surface of the electrolytic plating film 11. The metal thin film can be formed so as to cover the surface of the external electrode 13.

  For the base substrate 2, glass, ceramics, plastic, glass epoxy resin, or the like can be used. As the electronic element 5, a piezoelectric vibrating piece, a MEMS, an acceleration sensor, a light emitting element, a light receiving element, and other semiconductor elements can be used. The through electrode 3 can be made of Kovar, Invar, Permalloy, 42 alloy, iron-nickel alloy such as stainless steel, or other metal materials. The electrolytic plating film 11 can be a nickel film, a copper film, or other metal film.

(Second embodiment)
FIG. 2 is a process diagram showing a method for manufacturing an electronic device according to the second embodiment of the present invention. 3 and 4 are explanatory diagrams of each step in the method for manufacturing an electronic device according to the first embodiment of the present invention. The same portions or portions having the same function are denoted by the same reference numerals.

  As shown in FIG. 2, the method for manufacturing an electronic device of the present invention includes a through electrode forming step S1, an electronic element mounting step S2, a lid installation step S3, a conductive film forming step S4, and an electrolytic plating film forming step. S5 and external electrode formation process S6 are provided. In the through electrode forming step S1, the through electrode is formed in the plate thickness direction on the insulating base substrate. In the electronic element mounting step S2, an electronic element is mounted on one surface of the base substrate. In the lid installation step S3, the lid that houses the electronic element is bonded to the base substrate. In the conductive film forming step S4, a conductive film is formed on the other surface of the base substrate and the end face of the through electrode exposed on the other surface. In the electrolytic plating film forming step S5, an electrolytic plating film is formed on the surface of the conductive film by an electrolytic plating method. In the external electrode formation step S6, the electrolytic plating film and the conductive film are patterned to form external electrodes on the end face of the through electrode and around the end face.

  In the manufacturing method of the present invention, the conductive film is formed on the other surface of the base substrate by the conductive film forming step S4 after the through electrode forming step S1 and before the electronic element mounting step S2, and then electrolysis is performed. The plating film forming step S5, then the external electrode forming step S6 is performed, then the electronic element is mounted on one surface of the base substrate in the electronic element mounting step S2, and finally the lid installation step S3 is performed. Also good. Further, after the lid installation step S3 and before the conductive film formation step S4, the other surface of the base substrate 2 is ground or polished to form the end surface of the through electrode and the other surface of the base substrate flush with each other. In addition, a grinding step for removing the oxide film formed on the end face can be added. Thereby, it can prevent that the electroconductivity between a metal film and a penetration electrode falls. This will be specifically described below.

  FIG. 3 (S1) is a schematic cross-sectional view showing a state in which the through electrode 3 is formed on the insulating base substrate 2 in the through electrode forming step S1. As the base substrate 2, for example, an insulating substrate such as a glass substrate, a plastic substrate, or a glass epoxy resin substrate can be used. As the through electrode 3, Kovar, Invar, Permalloy, 42 alloy, iron-nickel alloys such as stainless steel, and other metal materials can be used. If a glass substrate is used as the base substrate 2 and Kovar is used as the through electrode 3, a thermal expansion coefficient can be approximated and a highly reliable package can be configured. Hereinafter, an example in which a glass substrate is used as the base substrate 2 and an iron-nickel alloy is used as the through electrode 3 will be described.

  The base substrate 2 made of glass is softened or melted, and through holes are formed by molding. The through hole is filled with an iron-nickel alloy wire, heated and softened, and the wire and glass are welded. After cooling the glass, both sides are polished and flattened, the end face M of the through electrode 3 is exposed to remove the oxide film, and the end face M and the surface of the base substrate 2 are formed flush with each other. For example, the planarized base substrate 2 has a thickness of 0.2 mm to 1 mm. The through hole of the base substrate 2 can also be formed by a sand blast method or an etching method.

  FIG. 3 (S2) is a schematic cross-sectional view showing a state in which the electronic element 5 is mounted on the base substrate 2 in the electronic element mounting step S2. A metal film is formed on one surface US by vapor deposition, sputtering, or the like, and the metal film is patterned by photolithography and etching to form the wiring electrode 8. The wiring electrode 8 may be formed by a printing method in addition to a vapor deposition method or a sputtering method. Next, the electronic element 5 is installed on the base substrate 2 by surface mounting via the metal bumps 10. Instead of surface mounting, the electronic element 5 may be bonded to the surface of the base substrate 2 with an adhesive or the like, and the wiring electrode 8 and the electronic element 5 may be electrically connected by wire bonding. When the electronic element 5 is a piezoelectric vibrating piece, the piezoelectric vibrating piece can be cantilevered on one surface US of the base substrate 2.

  FIG. 3 (S3) is a schematic cross-sectional view illustrating a state in which the lid body 6 is bonded to one surface US of the base substrate 2 in the lid body setting step S3. The same material as the base substrate 2, for example, a glass material can be used as the lid 6. The lid body 6 has a depression at the center, and a bonding material 9 is formed in advance on the upper end surface of the depression. As the bonding material 9, for example, a conductive film such as an aluminum film, a chromium film, or a silicon film, or a composite layer thereof is formed by a vapor deposition method, a sputtering method, or the like. Then, the electronic element 5 is accommodated in the central depression, and the base substrate 2 and the lid 6 are joined by anodic bonding. If the surroundings are evacuated at the time of bonding, the inside of the package in which the electronic element 5 is stored can be evacuated. For example, when a crystal vibrating piece is used as the electronic element 5, air resistance to physical vibration of the crystal vibrating piece can be eliminated by maintaining the inside of the package in a vacuum. Note that the glass substrate 2 and the lid 6 can be joined together by metal-to-metal joining or an adhesive in addition to anodic joining.

  FIG. 3 (S4) is a schematic cross-sectional view showing a state in which the conductive film 4 is formed on the other surface LS of the base substrate 2 in the conductive film formation step S4. The other surface LS of the base substrate 2 is polished or washed to remove the oxide film on the end face M. Next, a metal conductive film 4 is deposited on the other surface LS to a thickness of 0.05 μm to 0.5 μm by vapor deposition or sputtering. The conductive film 4 is deposited across the end faces M of the plurality of through electrodes 3. For example, a nickel film or a copper film is formed as the conductive film 4. Thereby, the other surface LS is converted into a conductive surface, and the plurality of through electrodes 3 are electrically connected. The conductive film 4 can use another metal film in addition to the nickel film. In this case, a material having good adhesion to the end face M and the base substrate 2 is selected. Further, it is desirable to select a material having a small difference in ionization tendency with respect to the metal film formed on the conductive film 4.

FIG. 3 (S5) is a schematic cross-sectional view showing a state in which the electrolytic plating film 11 is formed on the upper surface of the conductive film 4 in the electrolytic plating film forming step S5. An electrolytic plating film 11 is formed on the upper surface of the conductive film 4 by electrolytic plating. Since the conductive film 4 is formed across the plurality of end surfaces M, the electrolytic plating film 11 can be formed on the upper surfaces of all the end surfaces M by one electrolytic plating. A nickel film is deposited as the electrolytic plating film 11. Since the electrolytic plating method is used, the deposition rate is high, and a nickel film having a thickness of 1 μm to 10 μm can be formed in a short time. In addition to the nickel film, a copper film or other metal film can be formed.
FIG. 4 is a diagram for explaining the external electrode formation step S6. FIG. 4 (S6-1) is a schematic cross-sectional view showing a state in which the mask 12 is installed on the surface of the electrolytic plating film 11. As shown in FIG. A photosensitive resin film made of a resist is applied or pasted on the surface of the electrolytic plating film 11, and exposure / development is performed to form a mask 12 in the external electrode formation region. Instead of forming the mask 12 from the photosensitive resin film, the mask 12 may be formed by a printing method.

  4 (S6-2) and (S6-3) show the state where the etching process is performed to remove the electrolytic plating film 11 and the conductive film 4 in the region other than the mask 12, and the state where the mask 12 is removed thereafter. It is a cross-sectional schematic diagram to represent. As shown in FIG. 4 (S6-2), the electrolytic plating film 11 and the conductive film 4 are formed from regions other than the pattern of the mask 12 by a wet etching method using an acid or an alkali solution or a dry etching method using a reactive gas. Remove. Thereafter, as shown in FIG. 4 (S6-3), the mask 12 is removed and the external electrode 13 is formed. In addition, in order to prevent the surface and side surfaces of the electrolytic plating film 11 and the conductive film 4 from being oxidized and to ensure conductivity, gold is removed by electroless plating after the mask 12 is removed or before the mask 12 is installed. A film having a small ionization tendency, such as silver or platinum, can be formed.

  In this way, the conductive film 4 is formed across the end surfaces M of the plurality of through electrodes 3, and then, the electrolytic plating film 11 is formed on the surface of the conductive film 4 by the electrolytic plating method. Since the electroplating film 11 is completely sealed by the conductive film 4 and the electroplating film 11, and the electroplating film 11 is formed at a high speed, corrosion of the through electrode 3 is prevented and the highly reliable electronic device 1 is manufactured in a short time. Can do.

(Third embodiment)
FIG. 5 is a process diagram showing a method for manufacturing an electronic device according to the third embodiment of the present invention. This is a specific example of manufacturing an electronic device including a piezoelectric vibrator on which a piezoelectric vibrating piece is mounted as an electronic element. The present embodiment is a manufacturing method in which a glass wafer on which a large number of depressions are formed and a glass wafer on which a large number of electronic elements are mounted are overlapped and bonded to form a large number of electronic devices 1 simultaneously. The same steps are denoted by the same reference numerals.

  The electronic element mounted on the base substrate is a piezoelectric vibrating piece made of a crystal resonator or the like. The lid forming step S20 will be described. A plate-like glass wafer made of soda-lime glass is prepared. First, in the polishing, cleaning, and etching step S21, the glass wafer is polished to a predetermined thickness, and after cleaning, an etching process is performed to remove the outermost work-affected layer. Next, in the dent forming step S22, a dent is formed in the center of the region where each electronic device is formed by hot press molding. Next, in the polishing step S23, the upper end surface around the recess is polished into a flat mirror surface. Next, in the bonding material deposition step S24, a bonding material made of, for example, aluminum is deposited to a thickness of 50 nm to 150 nm on the surface of the lid body where the depression is formed by sputtering or vapor deposition. Next, in the pattern forming step S25, the bonding material is removed from the surface other than the upper end surface around the recess by photolithography and etching. In this way, a lid made of a glass wafer is formed.

  The piezoelectric vibrating piece creating step S30 will be described. The quartz crystal is sliced at a predetermined angle to form a quartz wafer, and then the quartz wafer is ground and polished to a constant thickness. Next, the work-affected layer of the quartz wafer is removed by etching. Next, metal films are deposited on both surfaces of the quartz wafer, the metal film is patterned by photolithography and etching, and processed into excitation electrodes, wiring electrodes, and mount electrodes having a predetermined shape. Next, the quartz wafer is processed into the outer shape of the piezoelectric vibrating piece by photolithography and etching or dicing.

  The base substrate forming step S40 will be described. A plate-like glass wafer made of soda-lime glass is prepared. First, in the polishing, cleaning and etching step S41, the glass wafer is polished to a predetermined thickness, and after cleaning, an etching process is performed to remove the outermost work-affected layer. Next, in the through electrode forming step S1, a through hole is formed in the thickness direction of the glass wafer by grinding with a hot press mold, or after setting a mask on the surface and etching or sandblasting. Next, a through electrode made of an iron-nickel alloy is embedded in the through hole. Next, in the grinding step S42, both end portions of the through electrode and both surfaces of the glass wafer are polished and flattened to expose the end surface of the through electrode. Next, in a wiring electrode forming step S43, a metal film is deposited on one surface of the base substrate by sputtering or vapor deposition, and patterned by photolithography and etching to form wiring electrodes.

  Next, in the electronic element mounting step S2, the piezoelectric vibrating piece is mounted on one surface of the base substrate. At the time of mounting, a conductive adhesive or a metal bump is placed on the wiring electrode of the base substrate, and a mount electrode of the piezoelectric vibrating piece is bonded thereon to fix the piezoelectric vibrating piece in a cantilever manner on the base substrate. Thus, the through electrode and the excitation electrode of the piezoelectric vibrating piece are electrically connected. Thus, a base substrate made of a glass wafer on which a large number of piezoelectric vibrating pieces are mounted is formed.

  Next, in the overlaying step S11, the lid is placed on the base substrate so that the piezoelectric vibrating piece is accommodated in each recess of the lid, and is pressed from above and below. Next, in the lid installation step S3, the base substrate and the lid are heated to a temperature of 200 ° C. or higher, and a voltage of several hundred volts is applied using the lid bonding material as the anode and the base substrate as the cathode. The base substrate and the lid body are joined via each other. When joining, the surroundings are kept in a vacuum.

  Next, in the conductive film forming step S4, a conductive film made of nickel is deposited on the other surface of the base substrate by vapor deposition or sputtering. Thereby, the other surface of the base substrate becomes conductive. Next, in the electrolytic plating film forming step S5, an electrolytic plating film made of a nickel film is formed on the surface of the conductive film by electrolytic plating to a thickness of 1 μm to 10 μm. In addition to the nickel film, a copper film can be formed as the conductive film and the electrolytic plating film.

  Next, in the external electrode forming step S6, a photosensitive resin film is applied or attached to the surface of the electrolytic plating film, and exposure / development is performed to form a mask in the external electrode formation region. Further, a mask may be formed by a printing method instead of the photosensitive resin film mask. Next, the electrolytic plating film and the conductive film are removed from regions other than the mask by wet etching or dry etching. Next, the external electrode is formed by removing the mask. Note that a gold thin film may be formed on the surface of the electrolytic plating film or the conductive film by an electroless plating method in order to prevent oxidization of the surface and side surfaces of the electrolytic plating film and the conductive film and to ensure conductivity.

  Next, in the cutting step S12, a scribe line is provided on the surface of the joined body, and the cutting blade is pressed to cleave, or is divided using a dicing blade or a dicing saw, and the individual electronic devices 1 are obtained. Next, in the electrical characteristic inspection step S13, the resonance frequency, resonance resistance value, and the like of the electronic device 1 are measured and inspected.

(Fourth embodiment)
FIG. 6 is a schematic top view of an oscillator 40 according to the fourth embodiment of the present invention. The electronic device 1 described in the first embodiment or the electronic device 1 manufactured by the manufacturing method described in the second or third embodiment is incorporated. As shown in FIG. 6, the oscillator 40 includes a substrate 43, the electronic device 1 installed on the substrate, an integrated circuit 41, and an electronic component 42. The electronic device 1 generates a signal having a constant frequency based on a drive signal applied to the external electrode, and the integrated circuit 41 and the electronic component 42 process the signal having the constant frequency supplied from the electronic device 1 to generate a clock signal. And so on. Since the electronic device 1 according to the present invention can be formed with high reliability and a small size, the entire oscillator 40 can be configured compactly.

DESCRIPTION OF SYMBOLS 1 Electronic device 2 Base substrate 3 Through-electrode 4 Conductive film 5 Electronic element 6 Lid 8 Wiring electrode 9 Joining material 10 Metal bump 11 Electroplating film 12 Mask 13 External electrode US One surface, LS The other surface LS, M End surface

Claims (11)

A through electrode forming step of forming a through electrode on an insulating base substrate;
An electronic element mounting step of mounting an electronic element on one surface of the base substrate;
A lid installation step for joining a lid for housing the electronic element to the base substrate;
A conductive film forming step of forming a conductive film on the other surface of the base substrate and an end surface of the through electrode exposed on the other surface;
An electrolytic plating film forming step of forming an electrolytic plating film on the surface of the conductive film by an electrolytic plating method;
An external electrode forming step of patterning the electrolytic plating film and the conductive film to form an external electrode around the end face of the through electrode and the end face.   The manufacturing method of the electronic device of Claim 1 which performs the said external electrode formation process after the said electronic element mounting process and a cover body installation process.   The method for manufacturing an electronic device according to claim 1, further comprising a metal film forming step of forming a metal film on a surface of the electrolytic plating film after the electrolytic plating film forming step.   The method of manufacturing an electronic device according to claim 1, wherein the through electrode is an iron-nickel alloy.   The method of manufacturing an electronic device according to claim 1, wherein the electrolytic plating film is a nickel film or a copper film.   The method of manufacturing an electronic device according to claim 3, wherein the metal film is a gold thin film.   The method of manufacturing an electronic device according to claim 1, wherein the electrolytic plating film has a thickness of 1 μm to 10 μm.   The method of manufacturing an electronic device according to claim 1, wherein the electronic element is a crystal vibrating piece. An insulating base substrate on which a plurality of through electrodes are formed;
An electronic device mounted on one surface of the base substrate;
A lid that houses the electronic element and is joined to the base substrate,
An external electrode is formed on the end surface of the through electrode exposed on the other surface of the base substrate and on the other surface around the end surface,
The external electrode is an electronic device having a conductive film and an electrolytic plating film formed on the conductive film by an electrolytic plating method.   The electronic device according to claim 9, wherein the through electrode is made of an iron-nickel alloy, the conductive film is made of a metal film, and the electrolytic plating film is made of nickel or copper. An electronic device according to claim 9,
An oscillator comprising: a drive circuit that supplies a drive signal to the electronic device.

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