JP2000101348A - Package for electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid defects, such as breakage of a ceramic board resulting from a difference between thermal expansion coefficients of both boards and improper operation of electronic components when the mounting of electronic components and circuit components in the package by connecting terminals provided to a bottom face of a ceramic board to a wiring pattern on a glass epoxy made printed circuit board in the package of a structure enclosing a space above the ceramic board including a crystal vibrator or the like, in a state in which the electronic components such as the crystal vibrator and the circuit components are mounted on the ceramic board. SOLUTION: A package for electronic components consists of a flat ceramic board 12 whose one side has a wiring pattern, electronic components 13, 14 mounted on the wiring pattern of the ceramic board 12, and a cap 15 that is made of an organic group board material and configured in a cave shape, and an opening of the cave cap 15 is enclosed by the ceramic board, so that the electronic components are placed in the opening of the cap 15. External terminals 16 for mount are formed to an outer bottom face of the cap 15 and the external terminals are connected electrically to the electronic components via the wiring pattern of the ceramic board and conductors provided to the cap.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a package structure of a surface mount type electronic component. Due to the difference in the coefficient of thermal expansion between the two substrates when connecting the terminals provided on the bottom surface of the ceramic substrate to the wiring pattern on the printed circuit board made of glass epoxy in a package surrounded by a case The present invention relates to an electronic component package that can solve the problem that the ceramic substrate is damaged.

[0002]

2. Description of the Related Art Various electronic component packages for surface mounting have been developed in which electronic components are mounted on a ceramic substrate and a space on the substrate including the electronic components is surrounded and concealed by a case. . FIG. 4 is a cross-sectional view showing a configuration and a mounting state of a surface mount type crystal oscillator as an example of such an electronic component package.
A flat ceramic substrate 2 having a wiring pattern on the surface and terminals for mounting on the bottom surface, a crystal resonator 3 and circuit components 4 mounted on the ceramic substrate 2, a crystal resonator 3 and circuit components 4 It has a metal lid 5 and the like fixed on the ceramic substrate 2 so as to cover it. This crystal oscillator 1
Is mounted by connecting a wiring pattern on a printed circuit board 6 constituting an electrical part of a device in which it is used and a mounting terminal on the bottom surface with solder or the like. The reason why the ceramic substrate 2 is used in the crystal oscillator is that it is possible to provide a printed resistor on the surface of the ceramic, and it is easy to reduce the number of components. However, the ceramic substrate has a disadvantage that it is easily broken. Further, since the printed circuit board 6 on the device side has a large board area, the material thereof is required to have high durability against stress, and therefore a glass epoxy plate is frequently used. However, since the ceramic substrate and the glass epoxy printed circuit board have different coefficients of linear expansion due to thermal change, when the ceramic substrate is soldered on the glass epoxy printed circuit board, as shown in FIG. There is a problem that stress is generated in the ceramic substrate and cracks C are generated in the worst case. Further, even when no damage such as cracks occurs, stress is applied to the crystal resonator via the ceramic substrate that has been distorted due to thermal changes, and the oscillation frequency of the oscillator fluctuates.

[0003]

The problem to be solved by the present invention is that an electronic component such as a crystal unit and a circuit component are mounted on a ceramic substrate and the space on the substrate including the crystal unit is reduced. Due to the difference in the coefficient of thermal expansion between the two substrates when connecting the terminals provided on the bottom surface of the ceramic substrate to the wiring pattern on the printed circuit board made of glass epoxy in a package surrounded by a case Another object of the present invention is to provide a package for an electronic component that can solve the problem that the ceramic substrate is damaged and the electronic component malfunctions.

[0004]

In order to solve the above-mentioned problems, a first aspect of the present invention relates to a flat ceramic substrate having a wiring pattern on one side, and an electronic component mounted on the wiring pattern of the ceramic substrate. A package made of an organic substrate material, which is formed in a concave shape, wherein the opening is closed by a ceramic substrate so that the electronic component is located in the opening of the concave cap. An external terminal for mounting is formed on the outer bottom surface of the cap, and the electronic component and the external terminal are electrically connected via a wiring pattern of the ceramic substrate and a conductor provided on the cap side. And The invention of claim 2 is
A flat ceramic substrate having a wiring pattern on one side, an electronic component mounted on the wiring pattern of the ceramic substrate, and an annular surrounding wall made of an organic substrate material,
An electronic component package having one opening closed by a ceramic substrate so that the electronic component is positioned within the opening of the annular surrounding wall, wherein external terminals for mounting are formed on an end surface of the other opening of the surrounding wall. The electronic component and the external terminal are electrically connected via a wiring pattern of the ceramic substrate and a conductor on the surrounding wall side.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. FIG. 1 is a cross-sectional view showing the structure of an electronic component package according to an embodiment of the present invention. This package 11 is, for example, a crystal oscillator and has a flat ceramic substrate 12 having a wiring pattern (not shown) on the lower surface.
And a crystal oscillator 13 and a circuit component 14 as electronic components mounted on the wiring pattern of the ceramic substrate, and a cap 15 made of glass epoxy and formed in a concave shape. Further, the opening 15a is closed by the ceramic substrate 12 so that the electronic components 13 and 14 are located in the opening 15a of the concave cap 15. External terminals 1 for mounting are provided on the outer bottom surface of the cap 15.
6 are formed, and the electronic components 13 and 14 are interposed via the wiring pattern of the ceramic substrate 12 and the wiring pattern on the cap 15 side.
And the external terminal 16 are electrically connected. The cap 15 is formed in a concave shape by forming a concave portion 17 on one side, and a pad 18a is formed by printing on the end surface of the side wall 15b.
And a conductor 18b for connecting to the inside extends through the thickness of the side wall 15b. On the ceramic substrate 12 side, a wiring pattern (not shown) connected to the pad 18a on the cap 15 side is arranged. When the opening 15a of the cap 15 is closed by the ceramic substrate 12, the ceramic pattern is formed via the pad 18a and the conductor 18b. Electrical connection between the wiring patterns (electronic components 13 and 14) on the substrate side and the external terminals 16 is ensured. Cap 15 is attached to ceramic substrate 12
When fixing on top, the pad 18a on the end face of the cap 15
And the wiring pattern on the ceramic substrate 12 may be connected using a conductive adhesive or solder. When solder is used, solder having a melting point higher than that of cream solder used when the present package 11 is reflow-mounted on the printed board 20 on the device side, for example, high-temperature solder may be used.

When the package 11 having the above configuration is mounted on the printed circuit board 20 on the device side, the external terminals 16 are mounted on the wiring pattern 21 on the printed circuit board 20 on the device side by reflow mounting. Should be done. The printed board 20 is generally made of glass epoxy of the same material as the cap 15. Electronic component package 11 having the above configuration
In the state where is mounted on the printed board 20, when a thermal change occurs, the printed board 20 and the bottom portion of the cap 15 expand and contract with the same expansion coefficient as shown in the schematic diagram of FIG. There is no danger of the breakage occurring.
Further, a side wall 15b is interposed between the bottom of the cap 15 and the ceramic substrate 12, and the stress generated when the bottom of the cap expands in the direction of the arrow is absorbed by the side wall 15b being bent as shown in the figure. Since the stress is relaxed, the distortion generated in the ceramic substrate 12 is reduced, and damage such as cracks does not occur, and malfunction of electronic components such as a crystal oscillator due to heat change does not occur.

FIG. 3 shows another embodiment of the present invention.
The electronic component package 11 of this embodiment differs from that of FIG. 1 in that an annular surrounding wall is used instead of the concave cap. The package 11 is, for example, a crystal oscillator, and has a flat ceramic substrate 12 having a wiring pattern (not shown) on a lower surface, a crystal resonator 13 and circuit components 14 mounted on the wiring pattern of the ceramic substrate.
(Electronic component) and an annular surrounding wall 25 made of glass epoxy
And consisting of Further, it has a configuration in which the opening 25a is closed by the ceramic substrate 12 so that the electronic components 13 and 14 are located in one opening 25a of the annular surrounding wall 25. Further, an external terminal 16 for mounting the bottom surface on the other opening 25b side of the surrounding wall 25 is formed, and the electronic components 13 and 14 and the external terminal 16 are connected to each other via the wiring pattern of the ceramic substrate 12 and the wiring pattern on the surrounding wall side. Are electrically connected.

The surrounding wall 25 is an annular wall made of glass epoxy, and a pad 26 is formed by printing on the upper end surface thereof, and a conductor 27 is formed in the surrounding wall 25 so as to electrically connect the pad 26 and the external terminal 16. Are arranged through. When the surrounding wall 25 is brought into contact with the ceramic substrate 12, a wiring pattern is formed on the substrate surface with which the pad 26 comes into contact. Siege wall 2
5 is fixed on the ceramic substrate 12, the surrounding wall 2
The pads 26 on the five end faces and the wiring pattern on the ceramic substrate 12 may be connected using a conductive adhesive or solder. When using solder, the printed board 2 on the equipment side
A solder having a higher melting point than the cream solder used when the package 11 is reflow-mounted on the substrate 0, for example, a high-temperature solder may be used. When the package 11 having the above configuration is mounted on the printed board 20 on the device side, reflow mounting is performed with the external terminals 16 placed on the wiring pattern 21 on the printed board 20 on the device side. good. The printed board 20 is made of glass epoxy of the same material as the surrounding wall 25. When the electronic component package 11 having the above configuration is mounted on the printed board 20 and a thermal change occurs, the printed board 20 and the surrounding wall 25 expand and contract at the same expansion rate. While there is no risk of damage such as cracks, most of the stress from the printed board 20 is absorbed and reduced by the deformation of the surrounding wall 25, so that the strain generated in the ceramic substrate 12 is reduced,
The occurrence of damages such as cracks and malfunctions of electronic components such as crystal oscillators due to thermal changes do not occur.
The present invention is not limited to the crystal oscillator, but can be generally applied to an electronic component package for surface mounting having a structure in which the electronic component is surrounded by a case or the like while the electronic component is mounted on a ceramic substrate. In addition, as a material for forming the cap, not only glass epoxy but also a material using another organic resin such as glass polyimide may be formed into a concave or annular shape.

[0009]

As described above, according to the present invention, the space on the substrate including the crystal unit and the like is surrounded by the case with the electronic parts and the circuit parts such as the crystal unit mounted on the ceramic substrate. When mounting by connecting the external terminals provided on the bottom surface of the ceramic substrate to the wiring pattern on the glass epoxy printed circuit board in the package of the structure, the ceramic expansion due to the difference in thermal expansion coefficient between the two substrates It is possible to solve the problems that the substrate is damaged or that the electronic component malfunctions. That is, in the invention of claim 1, a glass epoxy cap is used in place of the metal case used in the conventional electronic component package, and the glass case is connected via an external mounting terminal provided on the outer bottom surface of the cap. Since the electronic component package was mounted on the epoxy side printed board,
Mechanical strain applied from the equipment side printed board due to thermal change is not directly applied to the ceramic substrate, and deformation of the cap absorbs and relaxes distortion, so that large stress is not applied to the ceramic substrate,
Problems such as breakage of the ceramic substrate and malfunction of electronic components are eliminated. In the invention according to claim 2,
Using an annular surrounding wall made of glass epoxy instead of the cap of claim 1, bonding the surrounding wall to a ceramic substrate,
An external terminal provided on the end surface of the surrounding wall was used to mount the device on a glass epoxy device-side printed board. Therefore, the hard and easily breakable ceramic substrate and the glass epoxy printed board are not directly connected to each other, and the stress due to expansion and contraction of the printed board is absorbed and reduced by the glass epoxy surrounding wall interposed therebetween. Therefore, problems such as breakage of the ceramic substrate and malfunction of electronic components are eliminated.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of a package of an electronic component according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a state in which a stress due to a thermal change is applied to the mounted package of FIG. 1;

FIG. 3 is a configuration explanatory view of a package of an electronic component according to another embodiment of the present invention.

FIG. 4 is a diagram for explaining a configuration of a conventional example and a defect.

[Explanation of symbols]

Reference Signs List 11 package, 12 ceramic substrate, 13 crystal oscillator, 14 circuit component, 15 cap, 15a opening, 15b side wall, 16 external terminal, 17 recess, 1
8a pad, 18a conductor, 20 printed board, 21
Wiring pattern, 25 surrounding wall, 26 pads, 27
conductor.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H03H 9/10 H03H 9/10

Claims (2)

[Claims] 1. A flat ceramic substrate having a wiring pattern on one surface, an electronic component mounted on the wiring pattern of the ceramic substrate, and a cap made of an organic substrate material and formed in a concave shape. A package for an electronic component, the opening of which is closed by a ceramic substrate so that the electronic component is located within the opening of the concave cap, wherein external terminals for mounting are formed on the outer bottom surface of the cap. An electronic component package, wherein an electronic component and the external terminal are electrically connected to each other via a wiring pattern of a ceramic substrate and a conductor provided on a cap side. 2. An annular enclosure comprising a flat ceramic substrate having a wiring pattern on one side, an electronic component mounted on the wiring pattern of the ceramic substrate, and an annular enclosure wall made of an organic substrate material. An electronic component package in which one opening is closed by a ceramic substrate so that the electronic component is located in the opening of the wall, and an external terminal for mounting is formed on an end surface of the other opening of the surrounding wall, and the ceramic An electronic component package, wherein an electronic component and the external terminal are electrically connected to each other via a wiring pattern of a substrate and a conductor on the side of the surrounding wall.