JP2014067828A - Method for manufacturing electronic device and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a thin electronic device capable of stably keeping the conduction between an electronic component and an external electrode and easily forming a through electrode, and to provide an electronic device.SOLUTION: A method for manufacturing an electronic device 1 comprises the steps of: filling a hollow D of a base material 10 with an embedding metal 21; mounting an electronic component 50 on the base material 10; hermetically bonding the region covered by a cover material 60 and the base material 10; forming a base 11 and a through electrode 22 by polishing the bonded base material 10; and forming an external electrode 60.

Description

  The present invention relates to a method for manufacturing an electronic device typified by a crystal resonator or a piezoelectric element, and an electronic device.

  Since a crystal resonator is excellent in frequency characteristics, it is frequently used as a device, specifically, one of printed circuit board mounting components. Here, in order to stabilize the characteristics of the crystal resonator, it is necessary to block the influence of outside air. As an example of such a package structure, a “glass-ceramic composite and a flat package type piezoelectric component using the same” described later has been proposed (Patent Document 1).

  In the package described in Patent Document 1, a ceramic resonator piece, which is a material having substantially the same thermal expansion coefficient as that of a quartz resonator piece, is mixed in an electronic device in which a quartz resonator piece is placed in a base and a cap is put on the base. A package is constructed using a thing. However, since this package is a glass-ceramic composite, it is made by single-piece production by placing a crystal resonator piece on one base and covering the cap, so the productivity is extremely low. In addition, this package is difficult to process the glass-ceramic composite, which increases production costs.

  In order to eliminate these drawbacks, a method of manufacturing a package with glass that is easy to process has been proposed. As an example, an “electronic component package” described later is known (Patent Document 2).

  The outline of the electronic component package described in Patent Document 2 will be described with reference to FIG. In the electronic component package, a step (a) of forming a through hole in the base 110, a step (b) of pouring low melting glass into the through hole and fitting the metal pin 120, pushing the metal pin 120 and making the glass plate concave Step (c) for processing, step (d) for forming electrode 130 by printing, step (e) for mounting component 140 such as a crystal resonator on metal pin 120, cap 160 and base 110 via sealing material 150 The electronic device 100 is manufactured through the step (f) of sealing and bonding the components. Here, in the step (c), the metal pin 120 adhered and fixed to the base 110 can be obtained by welding the glass at a heating temperature equal to or higher than the softening point temperature (about 1000 ° C.) of the glass. In step f), confidentiality can be reliably maintained, and the electronic device 100 can be manufactured at low cost.

JP-A-11-302034 JP 2003-209198 A

  However, in the method for manufacturing the electronic device 100 described with reference to FIG. 5, the situation shown in FIG. 6 may occur in the step (c). Here, FIG. 6 is an enlarged view of the metal pin portion in the step (c). That is, as shown in FIG. 6C-1, when the metal pin 120 is short or when the push-in amount is small, the metal pin 120 is wrapped in the low melting point glass 170. For this reason, the situation where the electrical connection of the electrode 130 and metal pin 120 which are formed at a process (d) cannot be ensured may arise. Further, as shown in FIG. 6C-2, even if the metal pin 120 is pushed in as designed, the base 110 is exposed to a temperature equal to or higher than the softening point of the low-melting glass 170. 170 may cover the tip of the metal pin 120. Further, as shown in FIG. 6C-3, the metal pin 120 is exposed to a temperature of about 1000 ° C. As a result, an oxide film 180 grows around the metal pin 120, and the electrode 130 and the electronic component 140 are separated. There may be a situation where conduction is lost. In addition, there is also a demand to provide a low-cost and low-cost requirement for electronic components in recent years (eg, 2012 size, 0.6 mm).

  The present invention is made in view of such circumstances, and an object of the present invention is to provide an electronic device manufacturing method and an electronic device that can stably ensure electrical continuity between an external electrode and an internal component. is there.

In order to solve the above-described problems, the present invention provides the following means.
The method for manufacturing an electronic device according to the present invention includes a step of forming a recess in a glass base material, a step of filling a metal in the recess to form an embedded metal embedded in the recess, and an electron in the base material. The mounting process for mounting the component and electrically connecting the embedded metal and the electronic component, the bonding process for bonding the cover material covering the electronic component to the base material, and the side on which the electronic component is mounted are opposite to the base material A base is formed by polishing from the side, and a polishing step for exposing the embedded metal and an external electrode forming step for forming an external electrode at the exposed lower end of the embedded metal are provided.

Further, the filling step described above is characterized in that a buried metal is formed by performing a via fill plating process.
In the above polishing step, the cover material is polished from the side opposite to the side where the electronic component is accommodated.

In addition, the method further includes an individualization step of cutting the base and the cover.
The buried metal is copper. Further, the embedded metal is characterized in that it is made of an iron-nickel alloy instead of copper.

  The electronic device of the present invention includes a glass base on which an electronic component is mounted, a cover that is bonded to the base and covers the electronic component, and an external portion that is formed on the base and is opposite to the side on which the electronic component is mounted. The external electrode formed on the side, the electronic component and the external electrode are electrically connected, and the through electrode penetrates the base. The through electrode has a lower end formed on the external side, and the electronic component And an upper end portion formed on the mounting side and having a cross-sectional area larger than that of the lower end portion.

  According to the present invention, when the through electrode is formed, a step of performing via fill plating processing on the depression formed in the base material is used, and a step of inserting / pressing the metal pin is not used. Therefore, in the present invention, it is possible to avoid a situation in which the metal pin is encased in the low melting point glass or an oxide film is formed around the metal pin, so that the electrical continuity between the electronic component and the external electrode is stable. Can be kept.

  As described above, the present invention has an effect that it is possible to provide a method for manufacturing a small and thin electronic device and an electronic device that can stably maintain conduction between the electronic component and the external electrode and can easily form a through electrode. .

It is sectional drawing of the electronic device of embodiment which concerns on this invention. It is a figure which shows the manufacturing process of the electronic device of embodiment which concerns on this invention. It is a figure which shows the example which deform | transformed a part of manufacturing process of the electronic device of embodiment which concerns on this invention. It is a figure which shows the example which changed another part of the manufacturing process of the electronic device of embodiment which concerns on this invention. It is a figure which shows the manufacturing process of a prior art example. It is an expanded sectional view of the metal pin part of a prior art example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view of an electronic device according to the present invention. In the electronic device 1, an electronic component 50 is mounted in a hollow portion surrounded by a glass base 11 and a cover 61 and shielded from the outside air. The electronic component 50 is electrically connected to the external electrode 70 that is a terminal mounted on the substrate via the mounting portion 40, the internal wiring 30, and the through electrode 22. Here, the cover 61 is not limited to glass, and for example, when the electronic device 1 is a MEMS device such as a pressure sensor, a cover made of silicon or the like can be used. The cover 61 can be made of aluminum. The through electrode 22 has an upper end portion 22a on the side where the electronic component 50 is mounted and a lower end portion 22b on the outside air side, and the cross-sectional area of the upper end portion 22a is formed larger than the cross-sectional area of the lower end portion 22b.

  The electronic device 1 shown in FIG. 1 is a crystal resonator on which a tuning-fork type crystal resonator element is mounted as an electronic component 50. In the present invention, the electronic device 1 includes, but is not limited to, a device in which various electronic components that can be mounted on the base 10 such as a piezoelectric element, an AT cut crystal resonator, a semiconductor circuit, and various sensors are mounted.

  The through electrode 22 is made of copper. The through electrode 22 is not limited to copper. For example, an iron-nickel alloy or the like may be used in consideration of the thermal expansion coefficient with the base.

  The internal wiring 30 and the external electrode 70 are each formed of a metal film, and the outermost surface has a layer shape using a noble metal such as gold, silver, or platinum. Here, since the noble metal has a small ionization tendency and has corrosion resistance, it is possible to suppress long-term deterioration of the internal wiring 30 and the external electrode 70, so that the reliability of the electronic device 1 using the present invention is improved. be able to. In addition, as a diffusion preventing layer for preventing metal diffusion, a metal layer such as nickel may be formed under the surface layer formed of a noble metal.

  Moreover, the mounting part 40 which connects the internal wiring 30 and the electronic component 50 can use conductive adhesives, such as a silver paste, for example. In that case, the internal wiring 30 and the electronic component 50 are bonded by baking a conductive adhesive (mounting portion 40) such as a silver paste as a connection portion. However, depending on the configuration of the electronic component 50, the conductive adhesive may not be used as the connection portion. For example, when a gold film (gold film) is formed on the outermost surface of the internal wiring 30, gold bumps (not shown) formed on the electronic component 50 can be used as the mounting portion 40. In that case, the gold bump formed on the electronic component 50 and the gold film of the internal wiring 30 can be bonded together by using a gold-gold bonding or the like instead of the conductive adhesive.

  The external electrode 70 can also be formed of a conductive adhesive such as a silver paste that relieves stress during board mounting. The external electrode 70 may be coated with solder.

(Electronic device manufacturing method)
Next, a method for manufacturing the electronic device 1 according to the present embodiment will be described with reference to FIGS. FIG. 2 is a diagram showing a method of manufacturing an electronic device that is manufactured at the wafer level and finally cut by dicing or the like. The electronic device 1 according to the present embodiment is not limited to this, and may be formed as an individual package from the beginning.

FIG. 2 is a diagram showing a manufacturing process of the electronic device according to the present invention.
FIG. 2A is a step of forming a bottomed recess D that does not penetrate the base material 10 in the base material 10 (a recess formation step). The depression D has an opening A that opens upward and a bottom B that is closed inside the base material 10. The recess D is manufactured by sandblasting, laser processing, drilling, hot pressing, or the like. The opening area of the opening A is formed larger than the bottom area of the bottom B.

  FIG. 2B shows a step of applying the via fill plating layer 20 on the surface of the base material 10 where the recess D is present (filling step). In order to apply the plating layer 20, a thin film formed by sputtering or electroless plating may be formed as a base. Via fill plating is often copper, but iron-nickel alloys may be used in consideration of thermal expansion. At this time, as shown in FIG. 3, it may be formed only around the depression D using a resist or the like.

  FIG. 2C is a step of removing the plating layer 20 at a portion protruding from the base material 10. By this removing step, the embedded metal 21 which is a metal filled in the recess D is formed. This step facilitates the formation of the internal wiring 30 and the bonding with the cover material 60 which will be performed later.

  FIG. 2D is a process for forming the internal wiring 30. The internal wiring 30 is formed of a sputtered film using a metal mask. Further, as shown in FIG. 4, the internal wiring integrated type plating layer 20i may be formed by patterning in advance using photolithography or the like and forming the plating layer 20 later. By doing in this way, the removal process of FIG.2 (c) after a filling process can be skipped.

  FIG. 2 (e) is a diagram for explaining an electronic component connection process in which the electronic component 50 is installed and the internal wiring 30 and the electronic component 50 are connected so as to be electrically conducted via the mounting portion 40. Yes (mounting process).

  Here, the mounting part 40 which connects the internal wiring 30 and the electronic component 50 can use conductive adhesives, such as a silver paste, for example. In that case, the internal wiring 30 and the electronic component 50 are bonded by baking a conductive adhesive such as silver paste as a connecting portion. In addition, depending on the configuration of the electronic component 50, the conductive adhesive may not be used as the connection portion. For example, when gold is used for the outermost surface of the internal wiring 30, gold bumps formed on the electronic component 50 can be used as the mounting portion 40. In that case, the gold bump formed on the electronic component 50 and the gold film of the internal wiring 30 can be bonded together by using a gold-gold bonding or the like instead of the conductive adhesive.

  FIG. 2F is a diagram for explaining a process of joining the cover material 60 processed into a concave shape to the base material 10 in order to protect the electronic component 50 mounted on the base material 10 (joining process). In this step, a cavity C that is blocked from outside air is formed by the above-described one surface of the base material 10 and the concave portion of the cover material 60. Thereby, it can arrange | position in the state which sealed the electronic component in the cavity part C. FIG. In addition, the material of the cover member 60 may be appropriately selected from, for example, silicon, glass, aluminum, and the like in consideration of specifications required for the electronic component 50 such as a joining method and a degree of vacuum and cost. For example, when the electronic component 50 is a quartz crystal piece and the frequency is adjusted after the base material 10 and the cover material 60 are joined, it is desirable to select a transparent glass member for the cover 60. . The frequency can be adjusted by removing a part of the electronic component 50 by irradiating the laser from the outside of the cover 60. Moreover, as a joining method of the cover material 60 and the base material 10, adhesion, anodic bonding, gold-gold bonding, etc. can be used, for example.

  FIG. 2G is a step of polishing the base material 10 and the cover material 60 (polishing step). By this polishing, a small and thin electronic component is provided while being manufactured by batch molding of a wafer or the like. At the same time, it can be manufactured at low cost. In this step, the base 11 and the cover 61 are formed, and the through electrode 22 is formed. By polishing the base material 10 from the side opposite to the side where the cavity C exists, the portion of the embedded metal 21 in contact with the bottom B of the recess D is removed, and the through electrode 22 is formed. At this time, the through electrode 22 is formed with an upper end 22a on the cavity C side and a lower end 22b exposed to the outside air side. The cross-sectional area of the upper end portion 22a is formed larger than the cross-sectional area of the lower end portion 22b.

  FIG. 2H is a diagram for explaining a process of forming the external electrode 70 on the through electrode 22 by sputtering (external electrode forming process). By this step, the external electrode 70 comes into close contact with the polished surface of the through electrode 22 polished in the above-described polishing step. Further, by forming the external electrode 70 in a region including the exposed surface of the through electrode 22 when viewed from the direction perpendicular to the through axis of the through electrode 22, the airtightness and waterproofness of the cavity C can be further improved. Can do. Here, the external electrode 70 may be formed by a combination of sputtering, vapor deposition, and photolithography. Solder bumps may be formed in consideration of substrate mounting.

  FIG. 2I is a diagram for explaining a process of dividing the package into pieces (individualization process). That is, the step suggested by FIG. 2I is a step of forming a plurality of electronic devices on one base 10 and then separating the electronic devices into individual pieces. The joining surface between the base 11 and the cover 61 is cut so as to have a cutting width smaller than the joining width. In this process, depending on the material of the cover 60. Although the method of dividing into pieces by cutting varies, as an example, the electronic device can be divided into pieces by dicing or laser cutting. Thereby, the electronic device which concerns on this invention can be manufactured collectively, and the shortening of the manufacturing time and process in mass production of an electronic device, and cost reduction can be achieved.

  As described above, according to the method for manufacturing an electronic device according to the present embodiment, when the through electrode 22 is formed, the recess D is opened after the bottomed recess D formed in the base material 10 is subjected to the via fill plating process. It is formed by using a polishing process from the opposite side of the surface, and does not use a process of inserting / pressing a metal pin. For this reason, in the electronic device, it is possible to avoid a situation in which the metal pin is encased in the low melting point glass or an oxide film is formed around the metal pin, so that electrical conduction between the electronic component 50 and the external electrode 70 is achieved. Can be kept stable.

  Therefore, the present invention can be said to be a method for manufacturing an electronic device that can stably maintain conduction between the electronic component and the external electrode and can easily form a through electrode.

  Moreover, according to the method for manufacturing an electronic device according to the present embodiment, the plating layer 20 is formed of a conductive material made of a copper material or an alloy material such as an iron-nickel alloy. That is, when a copper material is used for the plating layer 20, a through electrode having a low resistance value can be produced. When an alloy is used for the plating layer 20, the hardness of the plating layer 20 can be changed, so that the strength of the through electrode can be appropriately changed. Furthermore, when an iron-nickel alloy is used as the alloy, the through electrode can be brought close to the thermal expansion coefficient of the base 10, and thus a more stable electronic device can be manufactured.

  The electronic device of the present invention includes, for example, an oscillator or a clock using the electronic device of the present invention as an oscillator, a portable information device including the electronic device of the present invention in a timekeeping unit, and an electronic device of the present invention as a radio wave such as time information. Can be used for an electronic device such as a radio timepiece provided in the receiver.

DESCRIPTION OF SYMBOLS 1 Electronic device 10 Base material which formed the hollow 11 Base 20 Plating layer 21 Metal with which the hollow was filled (embedded metal)
22 Through-electrode 30 Internal wiring 40 Mounting part 50 Electronic component 60 Cover material before polishing 61 Cover 70 External electrode 100 Electronic device 110 Base 120 Metal pin 130 Electrode 140 Electronic component 150 Sealant 160 Cap 170 Low melting point glass 180 Oxide film

Claims (7)

A dent forming step for forming a dent in a glass base material;
A filling step of forming a buried metal embedded in the depression by filling the depression with metal;
Mounting an electronic component on the base material, and electrically connecting the embedded metal and the electronic component;
A joining step of joining a cover material covering the electronic component to the base material;
Polishing the base material from the side opposite to the side on which the electronic component is mounted to form a base and exposing the embedded metal;
Forming an external electrode on the exposed lower end of the embedded metal; and
The manufacturing method of the electronic device characterized by the above-mentioned. In the manufacturing method of the electronic device of Claim 1,
In the filling step, the buried metal is formed by performing a via fill plating process. In the manufacturing method of the electronic device of Claim 2,
In the polishing step, the cover is formed by polishing the cover material from the side opposite to the side where the electronic component is accommodated. In the manufacturing method of the electronic device according to claim 3,
The method of manufacturing an electronic device, further comprising a singulation step of cutting the base and the cover. In the manufacturing method of the electronic device as described in any one of Claim 1 to 4,
The method of manufacturing an electronic device, wherein the embedded metal is copper. In the manufacturing method of the electronic device as described in any one of Claim 1 to 4,
The method of manufacturing an electronic device, wherein the embedded metal is made of an iron-nickel alloy. A glass base on which electronic components are mounted;
A cover joined to the base and covering the electronic component;
An external electrode formed on the base and formed on an external side opposite to the side on which the electronic component is mounted;
Electrically connecting the electronic component and the external electrode, and having a through electrode penetrating the base,
The through electrode includes a lower end portion formed on the outer side and an upper end portion formed on the side on which the electronic component is mounted and having a cross-sectional area larger than the cross-sectional area of the lower end portion. Electronic devices.

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