JP2762424B2 - Connection structure of electronic components and crystal oscillator using the structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure for electronic components, and more particularly to a connection structure for electrically and mechanically connecting components such as a crystal oscillator.

[0002]

2. Description of the Related Art As is well known, conventionally, when electrically connecting components constituting an electronic component, or mounting an electronic component on a printed wiring board and performing electrical connection, a conductive material such as solder or silver powder is used. The bonding has been performed using a conductive adhesive mixed with an insulating resin such as an epoxy resin.

[0003]

In most cases, a heat cycle test and an aging test are performed to secure or confirm the reliability of electronic components. The heat cycle test refers to the ambient environment temperature of an electronic component, for example, −40 ° C. → 25 ° C. for 3 minutes → 100 ° C. for 30 minutes → 25 ° C.
For 3 minutes → −40 ° C. for 30 minutes is repeated several hundred times. However, in the case of conductive bonding materials using epoxy resin, the conductive material becomes unstable due to cracks in the bonding material and peeling of the bonding surface with each part during such a cycle. was there. Such a phenomenon is manifested, for example, in a crystal oscillator described later as a decrease in output voltage due to an increase in resistance value, which may significantly reduce the reliability of electronic components.

[0004] In recent years, in the flow of automation of assembly of electronic devices, re-flow soldering has often been used to electrically and mechanically join electronic components to a printed wiring board. What is reflow soldering?
This is a method in which an appropriate amount of solder is supplied in advance to a joint portion, and the solder is melted by an external heat source to perform soldering. Inside the reflow furnace that supplies the heat source, the solder is heated to a temperature at which the solder can be melted. In such a case, if solder is used for bonding inside the electronic component, this solder melts,
Or, it may be softened, causing a short circuit accident or the like.

The present invention has been made to solve the above problems, and provides a connection structure of electronic parts which is resistant to aging or thermal fluctuation and is suitable for reflow soldering, and a crystal oscillator using the structure. It is intended to do so.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a structure for electrically and mechanically connecting components constituting an electronic component, wherein the connection for performing the electrical and mechanical connection is provided. The material is sandwiched between the parts to be joined. In the sandwiched state, the region of the low-melting-point metal is located at the center and mainly electrically connects the two components, and the region of the insulating joining material is the region of the low-melting-point metal. In this configuration, the mechanical bonding is performed by surrounding the region, and the heating is performed in the sandwiched state, so that the electro-mechanical bonding is advanced.
A base on which the lead terminals are implanted; a printed wiring board mounted on the upper surface of the base via a bonding material;
An electronic component mounted and installed on the upper surface of the printed wiring board, a quartz vibrating element plate also mounted via a support on the upper surface of the printed wiring board, and a cap for hermetically sealing, In the joining state, the region of the low-melting-point metal that mainly performs the electrical connection is at the center in the joining state, and the region of the insulating joining material that performs the mechanical joining surrounds the region of the low-melting-point metal. A crystal oscillator may be characterized in that electrical and mechanical bonding is advanced by performing heating in a sandwiched state. In such a crystal oscillator, a similar bonding configuration may be adopted for the electrical and mechanical connection of electronic components installed on a printed wiring board.

[0007]

A bonding material is sandwiched between components to be joined. In this sandwiched state, a region of a low-melting-point metal such as solder for mainly electrical connection and a region of an insulating resin for mechanical connection are formed. And the region of the low melting point metal is located in the center, and the surrounding area is made of insulating resin.Even if the volume changes due to the aging of the resin, the electrical connection is Since it is kept, there is no conduction failure between connected parts. Further, since the low melting point metal such as solder is located at the center, even if this solder is softened by heat, it is blocked by the surrounding insulating resin and does not flow out to the surroundings. Further, as will be described in Examples described later, heating to the low melting point metal and the insulating resin can be performed in one continuous step. Furthermore, the low-melting point metal, for example, solder, is in a state of being surrounded by an insulating resin, and is in contact with each of the components at the top and bottom. Electromechanical bonding proceeds in a state where it is difficult to contact, oxidation of the low-melting-point metal at the time of bonding is reduced, and a decrease in wettability is reduced. Therefore, the electrical joining property of the solder can be improved, and joining without using flux becomes possible.

[0008]

Next, the present invention will be described with reference to the drawings, taking a crystal oscillator as an example. 1 is an exploded perspective view showing an embodiment of the present invention, FIG. 2 is a side sectional view in a state where a cap is covered in FIG. 1, and FIG. 3 is a partially enlarged view of FIG. The quartz resonator blank 1 is formed of an AT-cut quartz plate, and is cut into a rectangular shape. Excitation electrodes 11 (the back surface is not shown) are provided on the front and back surfaces by means such as vapor deposition. The printed wiring board 2 is provided with through holes 21 and 22 in the vicinity of both ends in the longitudinal direction thereof. Supports 31 and 32 for the quartz vibrating plate are provided on the upper surface so as to face each other. The component 33 is mounted on the printed wiring board 2 via the bonding material 4. The bonding material 4 is formed of a low melting point metal solder 41 at the center and an insulating resin 42 such as an epoxy resin at the periphery thereof. High-temperature solder or lead to which silver or the like is added as the low melting point metal can be given. This joining can be performed by the following manufacturing examples. First, the insulating resin 42 is placed at a predetermined position on the printed wiring board 2.
Is applied, and a sheet-shaped solder 41 is placed at the center. Then, while applying a certain pressure, first, the parts to be joined are first electrically connected to each other by melting the solder, and then the surrounding insulating resin is cured while maintaining a predetermined temperature. The base 5 is provided with three terminals, of which the lead terminals 51, 53 penetrate electrically and independently through the insulating material 54, 55 such as glass to the upper surface of the base, and the remaining ground. The terminal 52 is connected to a metal part of the base 5. A bonding material 6 composed of a solder 61 and an insulating bonding material 62 is applied to the upper surface of the base, and the printed wiring board 2 is mounted on the base and heat-bonded while applying a constant pressure. The crystal vibrating element plate 1 on which the excitation electrodes are formed is mounted on the supports 31 and 32 of the printed wiring board, and is covered with a metal cap 7 to complete the crystal oscillator. The joining using the two joining materials 4 and 6 may be performed at the same time without any problem. Note that the present invention is not limited to the crystal oscillator, and is applied to a configuration in which a bonding material is sandwiched between components to be joined in various electronic components, and in this sandwiched state, electromechanical joining is performed. it can.

[0009]

According to the present invention, the joining material is sandwiched between the parts to be joined, and in this sandwiched state, the region of the low melting point metal such as solder which mainly performs the electrical connection and the mechanical connection are formed. And the region of the low melting point metal is located in the central part, and the periphery of the region is made of the insulating resin. However, since the electrical connection is maintained, there is no conduction failure between the connected components. Further, since the low melting point metal such as solder is located at the center, even if this solder is softened by heat, it is blocked by the surrounding insulating resin and does not flow out to the surroundings. Therefore, a short circuit accident with other electronic parts and the like is unlikely to occur, and a connection structure of electronic parts suitable for reflow soldering can be provided. In a crystal oscillator using such a connection structure, the output due to an increase in resistance value can be provided. A highly reliable crystal oscillator without a voltage drop can be provided.

Further, since heating to the low melting point metal and the insulating resin can be performed in one continuous step, the number of manufacturing steps can be reduced. Furthermore, since the low-melting point metal, for example, solder is in contact with each component in a state of being surrounded by the insulating resin, oxidation at the time of joining is reduced, and the electrical joining property of the solder can be improved, Bonding without using flux becomes possible. Therefore, conventionally, after the bonding, cleaning is performed to remove the flux, but this cleaning operation can be omitted.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a crystal oscillator according to the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is a partially enlarged view of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Quartz crystal base plate 2 Printed wiring board 33 Electronic component 4, 6 Joining material 41, 61 Solder (low melting point metal) 42, 62 Insulating resin 5 Base 7 Cap

Claims (3)

(57) [Claims] 1. A structure for electrically and mechanically connecting components constituting an electronic component, wherein a bonding material for performing the electromechanical connection is sandwiched between the components to be joined, and is in the sandwiched state. In the configuration, the region of the low-melting-point metal is located at the center and mainly performs electrical connection between the two components, and the region of the insulating bonding material surrounds the region of the low-melting-point metal and performs mechanical bonding. A connection structure for electronic components, wherein electrical and mechanical bonding is advanced by heating in a heated state. 2. A base on which lead terminals are implanted, a printed wiring board mounted on the upper surface of the base via a bonding material, and an electronic component mounted on the upper surface of the printed wiring board. A low-melting-point metal, which mainly comprises an electrical connection in a bonded state, comprising a quartz-crystal vibrating plate mounted on a top surface of a printed wiring board via a support and a cap for hermetic sealing. Region is at the center, the region of the insulating bonding material that performs the mechanical bonding is configured to surround the region of the low melting point metal, and by performing heating in the sandwiched state, the electrical mechanical bonding is performed. A crystal oscillator characterized by being advanced. 3. A base on which lead terminals are implanted, a printed wiring board mounted on an upper surface of the base via a bonding material, and an electronic component mounted on the upper surface of the printed wiring board via a bonding material. And a quartz vibrating plate mounted on the upper surface of the printed wiring board via a support, and a cap for hermetic sealing. Each of the bonding materials is mainly electrically connected in the bonded state. The region of the low-melting-point metal that performs the mechanical bonding is located at the center, and the region of the insulating bonding material that performs the mechanical bonding surrounds the region of the low-melting-point metal. By performing heating in the sandwiched state, electric Crystal oscillator characterized by promoting mechanical-mechanical bonding.