JP2000195977A - Package for electronic component and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a package for an electronic component and a manufacture thereof, wherein the reliability in airtighness is maintained satisfactorily and the functions of the electronic component will not deteriorate even is sulyicted to miniaturization. SOLUTION: There are provided a ceramic package 1, having a concave part of which upper part opens, a quartz oscillating board 3 which is an electronic element housed in the package, and a metal lid 2 bonded to the opening of the package. The ceramic package and the metal lid are bonded by first spot resistance welding or laser welding and then by soldering the entire surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package for electronic parts, and more particularly to a package for electronic parts requiring hermetic sealing.

[0002]

2. Description of the Related Art Examples of electronic components requiring hermetic sealing include quartz crystal products such as quartz oscillators, quartz filters and quartz oscillators. Each of them is hermetically sealed in order to form a metal thin film electrode on the surface of a quartz vibrating plate, which is an electronic element, and to protect the metal thin film electrode from the outside air.

[0003] Due to the demand for surface mounting of components, the configuration of these quartz-applied products which are hermetically housed in a ceramic package is increasing. In the case of using such a ceramic package, various joining methods are being studied for joining the package body and the lid. For example, there are various joining methods such as solder joining, low melting point glass joining, resistance welding, and electron beam welding. Recently, a configuration in which a brazing metal is melted and hermetically sealed by a local heating method using high-frequency heating has been studied. High-frequency heating is a technology that has been partly used for a long time, for example, melting solder by high-frequency heating,
An example of hermetic sealing is disclosed in the embodiment of JP-B-57-18372.

A configuration necessary for hermetic sealing by high-frequency heating will be described with reference to FIG. FIG. 3 shows a surface mount type crystal unit 6.
FIG. 4 is a schematic cross-sectional view of a state where the device is installed between high-frequency coils 5. A metallization layer 62 is formed on the upper surface of the bank portion 61 of the ceramic package 60, and a metal plating layer (not shown) of nickel or the like is formed on the upper surface. A metal brazing layer 64 such as silver brazing is formed on the metal lid 63 and is mounted on the bank. In addition, a quartz diaphragm on which an excitation electrode (not shown) is formed is installed inside the package,
After the necessary electrical connection is made, the metal cover is locally heated mainly by virtue of high frequency heating, and hermetically sealed by brazing.

[0005] High-frequency heating is characterized in that thermal heating can be performed at a predetermined temperature in a short time (for example, 1 to 1.5 seconds), so that thermal distortion is extremely small. However, it has been found that when the present invention is applied to sealing of a package as described above, the bonding state and the effect on the electronic elements inside the package change depending on the conditions even within a short time, and variations in quality occur. Then, when the progress of the joining was observed in chronological order, the progress was as shown in FIG. That is, as shown in FIG. 4 (a), in the initial stage of the heating and melting, the silver solder is in a molten state and partially forms the molten pool 64a, but the end of the metal lid is slightly upward. The situation was warped. As is well known, the high-frequency heating method generates heat by eddy currents, and the eddy currents are concentrated not on the metal cross sections but on the surface. That is, a temperature difference occurs between the surface of the object to be heated and the inside thereof, and this is considered to be one of the causes of the warpage.
If the heating is terminated in such a warped state, airtightness may be poor because only partial brazing is performed.

When the heating is further advanced as shown in FIG. 4 (b), the warpage of the end of the metal lid is corrected, and the metal lid is brought into a surface bonding state. When the heating is terminated in this situation, the airtightness is improved. Thereafter, when the heating is further advanced, the high temperature is transmitted to the central portion of the metal lid, and as shown in FIG. 4C, the silver solder formed on the metal lid starts to evaporate. Evaporated silver solder G
May contaminate the inside of the package, such as by adhering to electronic elements. In this case, although the airtightness is maintained well, the characteristics of the electronic element may be deteriorated. For example, when the electronic element is a quartz vibrating plate, frequency fluctuation, occurrence of non-oscillation, and the like may occur.

The state in which the airtightness is good and does not adversely affect the electronic element as shown in FIG. 4B is considerably short in terms of time, and the conditions under which the airtightness is substantially good (mainly the heating time) ) And the condition (mainly the heating time) that adversely affects the electronic element often coincided. Also, the metal brazing material is often formed on the entire surface of the metal lid because of its easiness, and this has resulted in promoting the adverse effect of the extra metal brazing material.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems. Even if the size of the package is reduced, the reliability of hermetic sealing is kept good and the function of the electronic component is reduced. It is an object of the present invention to provide a package for an electronic component and a method for manufacturing the package for an electronic component, which does not need to be performed.

[0009]

According to a first aspect of the present invention, there is provided an electronic component package comprising: a ceramic base; a metallized layer formed circumferentially around a main surface of the ceramic base; and an upper surface of the metalized layer. A first metal film layer and a second metal film layer formed at least corresponding to the first metal film layer;
An electronic component package comprising: a metal lid on which a metal film layer is formed, wherein at least one of the first metal film layer and the second metal film layer is formed of a brazing metal material; It is characterized in that the multilayered surface of the film layers is joined by spot resistance welding or laser welding at a plurality of locations and also by brazing on the entire surface.

According to the first aspect of the present invention, the warpage of the metal lid, which has occurred in the initial stage of brazing, can be suppressed by spot resistance welding or laser welding formed on the outer peripheral portion of the metal lid. Brazing can be completed at an early stage of heating and melting.

In order to manufacture such a package for an electronic component, a ceramic base, a metallized layer formed circumferentially around a main surface of the ceramic base, and a metallized layer A first metal film layer formed on an upper surface, and a metal lid on which a second metal film layer formed at least corresponding to the first metal film layer is formed, wherein the first metal film A method for manufacturing an electronic component package, wherein at least one of a metal layer and a second metal film layer is formed of a brazing metal material, wherein the first metal layer or the second metal layer corresponds to a metal lid. A step of contacting with a ceramic base, a step of spot-welding or laser-welding a plurality of locations on an outer peripheral portion of the metal lid, and a preliminary joining to the ceramic base; Heated to, or according to the ceramic substrate and the metal cover to hermetically braze contact method.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. 1 and 2, taking a surface mount type crystal unit as an example. FIG. 1 is an internal sectional view showing the present embodiment, and FIG. 2 is a plan view showing a spot resistance welding point sealed with a metal lid. The surface-mount type crystal unit includes a ceramic package 1 having a concave portion with an open top, a crystal plate 3 as an electronic element housed in the package, and a metal lid 2 joined to the opening of the package. Consists of

A ceramic package 1 having a concave shape when viewed in cross section.
Consists of a ceramic base 10 and a circumferential metal layer formed on the embankment 10a around the concave shape. The metal layer includes a metallized layer 11 made of tungsten or the like and a first metal film layer 12 formed on the metallized layer. The metal film layer 12 is in contact with the metallized layer and has a nickel plating layer 12a.
And an ultra-thin gold plating layer 12b formed on the nickel plating layer 12a. It should be noted that even if the gold plating layer 12b is not formed, the bonding property is not significantly affected.
In this embodiment, the thickness of each layer is about 25 to 30 μm for the metallized layer 11 and about 4 to 8 μm for the nickel plating layer 12a.
m, the thickness of the gold plating layer 12b is about 0.5 to 1.0 μm.

Further, electrode pads 13 and 14 are formed on the inner bottom surface of the ceramic package 1, and these electrode pads are electrically connected as extraction electrodes 17 and 18 to the bottom surface outside the package via connecting electrodes 15 and 16. Has been drawn to. A rectangular crystal vibrating plate 3 as an electronic element is mounted between the electrode pads 13 and 14. Although not shown, a pair of excitation electrodes are formed on the front and back surfaces of the quartz vibrating plate 3 and are led out to the electrode pads 13 and 14, respectively, and are conductively bonded by conductive bonding materials S1 and S2.

The metal lid 2 to be hermetically sealed forms a second metal film layer 21 on the entire lower surface of a metal base material 20 such as Kovar. Thereby, the second metal film layer 21 substantially corresponding to the peripheral metal layer 11 is formed.
Of course, the second metal film layer 21 corresponding to only the circumferential metal layer 11 may be formed circumferentially. The second metal film layer 21 is made of, for example, silver brazing, and is formed by, for example, a rolling technique to form a clad silver brazing layer. As described above, by forming the clad, there is an advantage that the release of gas at the time of melting is small and a bad influence on the inside of the package due to the gas can be avoided. To show the specific external dimensions, the external dimensions of the ceramic package are 3.2 mm in height, 2.5 mm in width, and 0.1 mm in height.
The outer dimensions of the lid are 3.1mm in length, 2.4mm in width, and 0.1mm in height (thickness), and the width of each metal film layer is about 0.4mm.
It has become about.

When the hermetic sealing is performed, the metal cover 2 and the respective metal layers of the ceramic package are positioned and overlapped, and the outermost peripheral portion of the metal cover is first subjected to spot resistance welding. 1 in FIG. 1 is a part of the spot resistance welding machine,
41 is a welding tip. In the present embodiment, the welding points 20a are performed at a total of eight points, but the welding points are required to be small enough to suppress the warpage of the metal lid in the next brazing. In addition, spot resistance welding can reduce the tip of the welding tip, so even if a positioning jig is used, there is no problem such as interference with the jig, and it should be applied to small electronic component packages. Becomes possible.

In addition, spot welding or linear welding may be performed using laser welding instead of the spot resistance welding.

Next, in the high frequency coil of the high frequency heating device,
The pre-bonded electronic component package is installed, and high-frequency heating is performed. Since the heating part is preferably limited to the metal lid part, it is installed so that high frequency is locally transmitted to the part as in the conventional example. By performing spot welding or the like, warpage of the metal lid, which has conventionally occurred in the initial stage of heating and melting, is suppressed. At the time of brazing, hermetic joining with the molten metal brazing material is performed from the initial stage of heating and melting. As a result, the time zone suitable for the joining is substantially extended, and a favorable airtight electronic component package can be obtained without adversely affecting the stored electronic elements.

Examination of appropriate bonding conditions using the ceramic package and the metal lid having the above-described configuration revealed that
Under the conditions of a frequency of 2 MHz and an output of 700 W, a package for electronic components in a good airtight junction state was obtained with a conduction time of 1 second.

The first metal film layer and the second metal film layer are not limited to the materials exemplified in the above embodiments, but may be soft solder such as solder. Of course, it is necessary to adjust the heating time and the like according to the melting point of the brazing metal used.

Although an example of a crystal oscillator has been described as an example of an electronic component, it is of course applicable to other piezoelectric oscillation devices such as a crystal oscillator and a crystal filter, and also to other airtight electronic components. .

[0022]

According to the present invention, warpage of the metal lid which has occurred in the initial stage of heat melting is suppressed by spot welding or laser welding, and the airtight joining by the molten metal brazing material is heated during brazing. It is performed from the initial stage of melting. As a result, the time zone suitable for the joining is substantially extended, and a favorable airtight electronic component package can be obtained without adversely affecting the stored electronic elements. Therefore, even if the package is miniaturized, it is possible to obtain a package for an electronic component in which the reliability of hermetic sealing is maintained well and the functions such as the electrical characteristics of the electronic component are not reduced.

[Brief description of the drawings]

FIG. 1 is an internal cross-sectional view according to a first embodiment.

FIG. 2 is a plan view according to the first embodiment.

FIG. 3 is a diagram showing a conventional example.

FIG. 4 is a diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic package 10 Ceramic base 11 Metallization layer 12 1st metal film layer 2 Metal cover 21 2nd metal film layer 3 Quartz crystal board (electronic element)

Claims (2)

[Claims] 1. A ceramic substrate, a metallized layer formed circumferentially around a main surface of the ceramic substrate, a first metal film layer formed on an upper surface of the metallized layer, and the first metal film An electronic component package comprising: a metal cover on which a second metal film layer formed at least corresponding to a layer is formed, wherein at least one of the first metal film layer and the second metal film layer is provided. An electronic component package formed of a brazing metal material, and wherein the superposed surfaces of both metal film layers are joined by spot resistance welding or laser welding at a plurality of locations and brazing the entire surface. 2. A ceramic substrate, a metallized layer formed circumferentially around a main surface of the ceramic substrate, a first metal film layer formed on an upper surface of the metallized layer, and the first metal film A metal lid on which a second metal film layer formed at least corresponding to the layer is formed, wherein at least one of the first metal film layer and the second metal film layer is formed of a brazing metal material. A step of contacting a metal cover and a ceramic base in a state where the first metal layer or the second metal layer corresponds, and spotting a plurality of locations on an outer peripheral portion of the metal cover. Welding or laser welding and preliminarily joining to the ceramic base; and then, locally heating the metal lid portion by a high-frequency heating method to air-tightly braze the ceramic base and the metal lid. Manufacturing method of electronic component package.