WO2003044857A1

WO2003044857A1 - Package for electronic component, and piezoelectric vibrating device using the package for electronic component

Info

Publication number: WO2003044857A1
Application number: PCT/JP2002/012088
Authority: WO
Inventors: Minoru Iizuka; Yoshikiyo Ogasawara
Original assignee: Daishinku Corporation
Priority date: 2001-11-19
Filing date: 2002-11-19
Publication date: 2003-05-30
Also published as: JP2003158211A

Abstract

A piezoelectric vibrating device, comprising a ceramic package (1) having an upwardly opening recessed part, a crystal vibrating plate (3) stored in the recessed part of the ceramic package (1), and a metal cover (2) connected to the opening part of the ceramic package (1), wherein a copper layer (22) and a silver solder layer (23) are formed in that order on the lower surface of the metal cover (2), and the metal cover (2) is connected to the ceramic package (1) by seam welding.

Description

Description Electronic component package and piezoelectric vibration device using the electronic component package

The present invention relates to a package for an electronic component used for an electronic device and the like, and a piezoelectric vibration device using the package for the electronic component. Background art

Examples of electronic components that require hermetic sealing include piezoelectric vibrating devices such as quartz oscillators, quartz filters, and quartz oscillators. In each of these devices, a metal thin-film electrode is formed on the surface of the quartz plate, and hermetically sealed to protect the metal thin-film electrode from the outside air.

These piezoelectric vibrator depises are required to have components mounted on the surface, and in this surface mounting, the configuration for hermetically sealing and storing components mounted in a ceramic package tends to increase. Under such circumstances, when using this ceramic package, various techniques have been disclosed as a joining method of the package body and the lid.

As such a technique, Japanese Patent Application Laid-Open No. 2000-236365 discloses a package for storing an electronic element, a metal film layer formed on each of metal lids, and a method for forming these metal film layers into a seam. A technique for hermetically sealing by electric resistance welding such as welding has been disclosed. In such a configuration, the meniscus portion is not required unlike the conventional seam welding using a seal ring (ring-shaped metal frame), so the reliability of hermetic sealing by electric resistance welding is reduced. In addition to this, there is obtained an advantage that the volume ratio of the portion for storing the electronic component to the external size of the package can be increased. These advantages can lead to an increase in the size of the electronic elements to be housed, and an increase in the number of electronic elements that can be housed. For multifunctional electronic components I was able to deal with it, and I was getting the effect.

In conventional seam welding using a seal ring, although the seal ring has the above-mentioned disadvantages, the presence of this seal ring acts to absorb thermal distortion when the welding temperature at the time of hermetic sealing becomes overheated This is effective in that it can prevent package damage due to thermal distortion. Such thermal distortion requires a certain degree of accuracy in its setting management to reduce variations such as current values during welding. In the technique described in Japanese Patent Application Laid-Open No. 2000-236365, instead of a seal ring, a metal braze is used to absorb thermal strain, but such setting management is not sufficient. In some cases, if overheating occurs, thermal strain may not be absorbed sufficiently. Disclosure of the invention

The present invention can sufficiently cope with such an overheating state at the time of welding, buffers thermal distortion, improves the reliability of hermetic sealing, secures a storage space for electronic elements, and enables miniaturization. It is another object of the present invention to provide an electronic component package that can reduce the manufacturing cost and a piezoelectric vibration device using the electronic component package.

In order to achieve the above object, an electronic component package according to the present invention comprises a package base and a first metal layer formed on a main surface of the package base and along the outer periphery thereof. An electronic component comprising: a metal film layer of a first metal film layer; and a metal lid formed corresponding to the first metal film layer and having a second metal film layer formed thereon by fusion bonding with the first metal film layer. A metal package, wherein a metal brazing layer is formed on the second metal film layer, and at least a copper layer is formed between the metal brazing layer and the metal lid.

In this configuration, the package base is provided with a recess for accommodating an electronic element, and has a ridge on the main surface of the package base and on the outer periphery thereof, and a first metal film layer on the upper surface of the ridge. In addition to the above, the metal lid may be provided with a second metal film layer formed corresponding to the first metal film layer and fusion-bonded with the first metal film layer. According to the above configuration, since the metal brazing layer is formed on the metal lid and at least the copper layer is formed between the metal brazing layer and the metal lid, the metal brazing layer is supplied when the metal brazing is melted. Heat distortion due to heat can be absorbed by the copper layer. Due to the buffer function of the copper layer, even when the heat of fusion is heated, excessive stress is not transmitted to a package made of, for example, ceramic. In addition, since the structure in which the copper layer is formed on the metal lid side is the joining of metal materials, the joining can be performed using the ductility or the characteristics of the intermetallic joining, so that the joining is facilitated.

The fusion bonding between the first metal film layer and the second metal film layer is preferably performed by seam welding or beam welding. Seam welding is a well-known technique, and is a type of resistance welding. When a metal lid is energized while pressurizing it, pressure is applied to the package together with thermal distortion due to Joule heat. Also, beam welding is a welding method using, for example, an electron beam or a laser beam, but the thermal distortion is large due to a rapid temperature rise in the beam irradiation area. In such a fusion bonding, mechanical or thermal stress can be reduced by forming a copper layer.

Further, the brazing metal layer and the copper layer may be formed by being clad with a metal lid. Cladding involves forming a brazing filler metal and a copper layer on a metal lid by a rolling method.Since pinda is not used, the release of gas during melting is small, and the adverse effect of gas on the inside of the package is avoided. Further, the metal brazing layer is preferably any one of silver brazing, gold brazing and nickel brazing.

In the present invention, the copper layer is interposed between the metal lid and the metal brazing layer to provide a certain cushioning function.However, it is possible to obtain a more effective buffering function when the copper layer has a predetermined thickness. it can. Specifically, a package base, a first metal film layer composed of a plurality of metal film layers formed on the main surface of the package base and along the outer periphery thereof, and a first metal film layer corresponding to the first metal film layer A package for an electronic component, comprising: a first metal film layer formed on the first metal film layer; and a metal lid on which a clad silver brazing layer formed by fusion welding by seam welding is formed. A clad copper layer is formed between the metal cover and the metal lid, and the copper layer has a thickness of 10 m to 50 m. With a configuration in the range of m, a more effective buffer function can be obtained. If the copper layer is smaller than 10 μπι, the copper buffer layer is too thin to provide a sufficient copper buffer function, so that the allowable current range during seam welding is narrowed and control becomes difficult. When the copper layer is larger than 50 zm, the allowable current range is widened because the copper layer is too thick, but sufficient melting cannot be obtained unless the absolute value of the current is increased. As a result, it becomes difficult to control heat as a whole, and the thickness of the metal lid as a whole hinders a reduction in height. In the present invention, the thickness of the copper layer is more preferably in the range of 20 / m to 40 / im, and the allowable current range can be further widened and the current value can be suppressed.

Next, the grounds for setting the thickness of the copper layer of the present invention to the above-described limited value will be described. Fig. 6 shows the range of current values that allow seam welding when the thickness of the copper layer interposed between the metal lid and the silver brazing layer is changed.

The package used for the experiment was a ceramic package with external dimensions of 4.9 mm on the long side, 3.1 mm on the short side, and 0.75 mm in thickness. The more detailed configuration is the same as the configuration shown in the first embodiment described later. The base (base material) of the metal lid is made of Kovar, and an Eckel layer is formed on the upper surface, that is, the non-bonding surface with the package, and the copper layer and the silver brazing layer are sequentially clad on the lower surface, that is, the bonding surface with the package. Formed. In addition, a metal film layer was formed in the order of a tungsten metallized layer, a nickel layer, and a gold layer on a bank portion of a ceramic base serving as a package base. The thickness of the silver layer was set to Ο ずつ μπι, and the thickness of the copper layer was increased by 10 μm at a time, and the range of current values that allowed seam welding was measured.

As a result, as shown in FIG. 6, in the configuration corresponding to the conventional example in which no copper layer is formed, the current value is relatively low, but the allowable setting range is narrow. By setting the thickness of the copper layer to Ο Ο μπι, the lower limit of the current value is reduced and the allowable setting range is widened, so that a practically favorable bonding environment can be obtained. In the range where the thickness of the copper layer is set to 20 to 40 Aim, the lower limit gradually increases, but the allowable setting range is further expanded. When the thickness of the copper layer is set to 50 μηι, the allowable setting range is wide, but the lower limit of the current value has risen, and there is no practical problem. It can be understood that a current is required to flow. Set the thickness of the copper layer to 60 μπι In this case, the allowable setting range is slightly narrower, and the lower limit of the current value is relatively large. In this case, fine control is required at the time of welding.

Furthermore, we incorporated the thickness of the silver brazing layer into this verification experiment, and conducted a verification experiment on the relationship between them.

The configuration of the package and metal lid, etc., to be tested are the same as those described above, but in this experiment, the thickness of the copper layer was set to 30 μm, 50 μππι, and the thickness of the silver solder was set to Two types of 10 m and 15 μπι were set, and samples of these combinations were created. The horizontal axis in FIG. 7 shows the thickness of the copper layer in the upper row and the thickness of the silver brazing layer in the lower row for each of these combinations. The silver solder used here is a kind of silver solder, "B Ag-8". In the results of the verification experiment shown in Fig. 7, when the thickness of the copper layer is 30 μππ and the thickness of the silver brazing layer is changed from 10 im to 15 m, the allowable range is slightly narrowed. Is within the range where there is no practical problem. This shows the same tendency even when the thickness of the copper layer is as thick as 50 μηι, but in this case, since the lower limit is increased, a slight decrease is observed in practical use.

From the above experimental results, it can be understood that the thickness of the copper layer is preferably from 10 / zm to 50 m, and more preferably from 20 / m to 40 μππ. The electronic component package can be applied to a piezoelectric vibration device in which a piezoelectric vibration element or a piezoelectric vibration element and a circuit element for driving the piezoelectric vibration element are housed. Piezoelectric vibrating devices such as quartz vibrators require high airtightness to protect their electrodes, but the electronic component package of the present invention is optimal. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an exploded perspective view of an embodiment of an electronic component package according to the present invention. FIG. 2 is a sectional view taken along line XX in FIG.

FIG. 3 is a schematic cross-sectional view showing the configuration of the metal lid applied to the present embodiment. FIG. 4 is a schematic cross-sectional view showing another configuration of the metal lid applied to the present embodiment. is there.

FIG. 5 is a schematic cross-sectional view showing another configuration of the metal lid applied to the present embodiment.

FIG. 6 is a graph showing verification experiment data of the embodiment of the piezoelectric vibration device of the present invention.

FIG. 7 is another graph showing verification experiment data of the embodiment of the piezoelectric vibration device of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

A first embodiment according to the present invention will be described with reference to FIGS. 1 to 3 by taking a surface-mounted crystal oscillator as an example. FIG. 1 is an exploded perspective view of the present embodiment,

FIG. 2 is a sectional view taken along line X--X in FIG. FIG. 3 is a schematic cross-sectional view showing the configuration of the metal lid applied to the present embodiment.

The surface-mount type crystal unit 10 includes a ceramic package 1 having a concave portion 1 y with an open top, a crystal vibrating plate 3 which is a piezoelectric vibrating plate housed in the concave portion 1 y of the ceramic package 1, and a ceramic package 1. A metal footer 2 joined to the opening of the package 1.

The ceramic package 1 is concave in cross section. A metal layer 11 is formed on the bank 10a around the concave shape. Although not shown in detail, the metal layer 11 includes a metallized layer made of, for example, tungsten or molybdenum, and a metal layer made of nickel, gold, or the like formed on the metallized layer. Castellations C 1, C 2, C 3, and C 4 are formed in the upper and lower squares on the outer peripheral side surface of the ceramic package 1. Metal conductors 14 and 15 are formed below castellations C 1 and C 2, and these metal conductors 14 and 15 are electrically connected to electrode pads described later. In the castellations C 3 and C 4, metal conductors 16 and 17 are formed from the upper end to the lower end. The metal layers 11 and the ground terminals E 3 and E 4 ( (E 3 is not shown).

As shown in FIG. 2, the ceramic package 1 has a rectangular A plate la, a first ceramic frame 1 b having a large center portion and an outer size substantially equal to that of the ceramic package 1, and a second ceramic frame having substantially the same shape as the first ceramic frame 1 b Each of these layers is laminated and integrally fired. The metal layer 11 is formed on the upper surface of the second ceramic frame 1c.

Further, electrode pads 12 and 13 are formed on the inner bottom surface of the ceramic package 1, and these electrode pads are connected via connecting electrodes 12a and 13a (13a is not shown). Deposed terminals E 1 and E 2 (E 2 not shown) are electrically drawn out from the bottom of the package. A rectangular crystal vibrating plate 3 as a piezoelectric vibrating plate is mounted between the electrode pads 12 and 13. A pair of excitation electrodes 3 1, 3 2 (32 not shown) are formed on the front and back surfaces of the quartz vibrating plate 3, and each excitation electrode is led out to an electrode pad 12, 13, respectively. Conductive bonding is performed by a conductive bonding material (not shown). As described above, the present embodiment has a configuration in which the crystal oscillator is led out at one end in the long side direction. The device terminals E 1 and E 2 may be led out to one end in the short side direction of the crystal unit.

The metal cover 2 for hermetically sealing the ceramic package 1 has a structure in which a metal film layer is formed on the upper and lower surfaces of a metal base material 20 such as Kovar. A nickel layer 21 is formed on the upper surface of the metal cover 2, that is, on the non-bonded surface, by plating or the like, and a copper layer 22 and a silver brazing layer 23 are formed on the lower surface of the metal cover 2, that is, on the ceramic package 1 side. It is formed. The copper layer 22 and the silver brazing layer 23 are formed by, for example, a rolling technique and are clad. By forming a clad, there is an advantage that the gas is not released at the time of melting, and a bad influence on the inside of the package due to the gas can be avoided.

The joining of the metal film layers of the metal cover 2 and the ceramic package 1 is performed, for example, using the same method as seam welding. That is, in a state where the first metal film layer 11 and the second metal film layer (silver brazing layer 23) are superimposed and positioned, the ridge of the metal lid is energized by the welding roller 1 of the parallel seam welding machine while energizing. Press and run (not shown). As a result, mainly the silver solder of the metal lid is melted and hermetic bonding is performed. Before seam welding, which is the main welding, the ceramic package 1 and the metal lid 2 are spot-melted. If temporary welding is performed by contact, positioning can be performed reliably. Alternatively, the hermetic sealing may be performed by a technique such as laser beam welding.

The configuration of the metal film layer formed on the metal lid is not limited to the present embodiment. For example, as shown in FIG. 4, a metal film layer composed of a copper layer 22 and a silver brazing layer 23 is formed only on the lower surface of Copearl 20 as a metal base material, that is, only on the ceramic package side, and the metal film is formed on the upper surface. A configuration in which no layer is formed may be employed.

Further, as shown in FIG. 5, nickel layers 21 and 24 are formed by plating on the upper and lower surfaces of Kovar 20, which is a metal base material, respectively, and the nickel layer 24 is further formed on the lower surface. A configuration in which a metal film layer composed of the copper layer 22 and the silver brazing layer 23 is formed in this order may be used. Further, the copper layer and the silver brazing layer or the silver brazing layer may be formed only in a region corresponding to the first metal film layer formed on the ceramic package 1.

In addition, in the configuration as a piezoelectric vibration device, a structure in which a piezoelectric vibration plate is mounted in a ceramic package is used.A circuit for driving the piezoelectric vibration plate includes an IC, a resistor, and the like, which constitute an oscillation circuit. A configuration in which the above circuit elements are integrally housed may be adopted. In the case of the latter configuration, it is necessary to provide a metal film wiring for electrically connecting each circuit element on the ceramic package side. Industrial applicability

As described above, the electronic component package according to the present invention can be made more compact while securing the storage space for the electronic element, has high hermetic sealing reliability, and can reduce the manufacturing cost. This is useful for piezoelectric vibration devices using electronic component packages.

Claims

The scope of the claims

1. A package base, a first metal film layer including a plurality of metal film layers formed on the main surface of the package base and along the outer periphery thereof, and formed corresponding to the first metal film layer. An electronic component package comprising: a first metal film layer and a metal lid on which a second metal film layer to be melt-bonded is formed, wherein a metal brazing layer is formed on the second metal film layer. An electronic component package, wherein at least a copper layer is formed between the metal brazing layer and the metal lid.

2. The package base is provided with a recess for accommodating an electronic element. The package base has a bank on the main surface and on the outer periphery thereof, and a first metal film layer is formed on the top of the bank. And a second metal film layer formed on the metal lid corresponding to the first metal film layer and melt-bonded to the first metal film layer. The electronic component package according to claim 1.

3. The electronic component package according to claim 1, wherein the fusion bonding is performed by seam welding or beam welding.

4. The electronic component package according to claim 1, wherein the metal brazing layer and the copper layer are formed by being clad on the metal lid.

5. The optical filter according to claim 1, wherein the metal brazing layer is one of silver brazing, gold brazing and nickel brazing.

6. A package base, a first metal film layer formed of a plurality of metal film layers formed on the main surface of the package base and along the outer periphery thereof, and a first metal film layer formed corresponding to the first metal film layer. An electronic component package comprising: a first metal film layer; and a metal lid on which a clad silver brazing layer that is melt-bonded by seam welding is formed, wherein a gap between the silver brazing layer and the metal lid is provided. A package for electronic components, wherein a clad copper layer is formed, and the copper layer has a thickness in a range of 10 to 50 μπι.

7. A piezoelectric vibrating element or a piezoelectric vibrating element and a piezoelectric vibrating element for driving the piezoelectric vibrating element inside the package for an electronic component according to any one of claims 1 to 6. Piezoelectric Vibration Depth ₍