JP3401781B2 - Electronic component package and method of manufacturing electronic component package - Google Patents

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 particularly to a package for electronic parts which requires hermetic sealing.

[0002]

2. Description of the Related Art Crystal-applied products such as a crystal oscillator, a crystal filter, and a crystal oscillator are given as examples of electronic parts requiring hermetic sealing. In each of these, a metal thin film electrode is formed on the surface of the crystal diaphragm, and the metal thin film electrode is hermetically sealed in order to protect the metal thin film electrode from the outside air.

Airtight sealing methods include solder joining, low melting point glass joining, resistance welding and electron beam welding. As an airtight sealing method using resistance welding, a crystal oscillator using an HC-49 / U type base is widely used. This is a structure in which a metal cap is hermetically sealed by resistance welding with a base in which a lead terminal is implanted in a metal shell in a state of being insulated from each other via insulating glass, and an electronic device having a lead terminal such as a crystal unit. It is widely used as a method for hermetically sealing parts.

According to such a joining method by resistance welding, metal-to-metal joining is performed, so that a sealing method having high airtightness can be obtained. However, it is necessary to press-contact the base and the cap at the time of hermetically sealing, and the distortion at the time of press-contact may adversely affect an electronic element such as a crystal diaphragm stored in the package.

Further, as shown in a conventional example of Japanese Patent Application Laid-Open No. 7-326687, a seal ring (metal frame) formed in an opening portion of a ceramic package and a metal lid are provided.
A joining method corresponding to surface mounting for hermetically sealing by seam welding, which is a kind of resistance welding, is also adopted.

The structure required for seam welding will be described with reference to FIG. FIG. 6 is a partially enlarged sectional view of the ceramic package and the metal lid. A seal ring 71 made of Kovar or the like is joined to the upper surface of the opening 70a of the ceramic package 70 by brazing. A metal lid 72 made of Kovar or the like is mounted on the seal ring, and a pair of welding rolls 73 (the other one is not shown) are energized while tracing the outer edge of the metal lid 72 to seal the metal lid and the seal. Had joined the rings. The outer circumference of the metal lid is formed to be slightly smaller than the outer circumference of the seal ring.
Are formed to ensure the joining of the two.

However, as is clear from FIG.
When seam welding is performed, the meniscus portion a of the brazing material is required on the upper surface 70a of the opening, and the above-described step portion b is required. Therefore, the substantial joint portion between the metal lid and the seal ring becomes the joint region c. For example, in the case of a package having a length of 6 mm and a width of 3 mm, the meniscus width a1 is 0.2 mm and the step width b1 is 0.1 mm.
mm, and the width c1 of the joining region is about 0.2 mm. The bonding area of 0.2 mm is substantially the minimum dimension in terms of airtight reliability. That is, in seam welding, the joint area c
In order to obtain the above, it is necessary to form the meniscus portion a and the stepped portion b, and in the case of a microminiaturized electronic component, the electronic element housing area cannot be secured, which is not suitable for miniaturization of the electronic component.

Further, it is necessary to bring the welding tip into contact with the members to be joined at the time of joining, but as each component becomes minute, the welding tips and the like interfere with each other, and it is difficult to reduce the size. There were also problems.

As a means for joining the members to be joined in a non-contact manner, a method of hermetically sealing by electron beam welding or laser beam welding has been considered, as shown in JP-A-8-46075.

However, even in such various beam welding, a jig for positioning and fixing the metal lid on the case is required at the time of welding. It has been difficult for such a jig to cope with miniaturization of each component.

Solder joining has long been used as a method for hermetically sealing a package for electronic parts. For example, Japanese Unexamined Patent Publication No. 52-22493 discloses a structure in which a soft brazing material such as solder is formed on the sealing surface of the lid and sealing is performed. In this publication, solder or the like formed by thermocompression is melted, and solder joining is performed by applying pressure to the lid by mechanical contact with heating. Although not specified in this publication, a jig for positioning the lid is essential in such solder joining, and thermocompression bonding is performed with the jig positioned. As described above, there is a problem in that a jig is required for soldering and it is not possible to cope with miniaturization of each component.

[0012]

As described above, in recent years, there has been a demand for finer electronic components, and even in the field of piezoelectric vibrators, which have been conventionally difficult to miniaturize,
For example, a surface mount type crystal unit having an outer size of 3 mm in length, 2 mm in width and 0.8 mm in height has been devised. Such a crystal unit needs to be adapted to the miniaturization of the crystal diaphragm, and a package for storing the crystal unit needs to be devised, so that the technology used in the past cannot cope with it.

The present invention has been made to solve the above-mentioned problems, and even in a microminiaturized electronic component, the bonding between the ceramic package housing the electronic element and the lid can be performed without using a positioning jig. An object of the present invention is to provide an electronic component package which can be positioned at a predetermined position and can be hermetically sealed surely, and a manufacturing method thereof.

[0014]

The present invention has been made by paying attention to the surface tension of a molten low melting point metal (solder or the like) or glass. The low melting point metal layer or the low melting point glass layer is provided at a predetermined position. It is formed on the surface of the base material, and the self-correction (self-alignment) function of the surface tension is made to function to position and perform airtight bonding.

A package for electronic parts according to claim 1 is
A ceramic base, a metal layer having a melting point higher than that of a low-melting metal or solder formed circumferentially around the main surface of the ceramic base, and a melting point of the low-melting metal or solder formed on the ceramic base. Of the low melting point metal layer or the solder layer bonded to correspond to the high melting point metal layer, and the lid is formed by setting the ambient temperature to the melting temperature of the low melting point metal layer or the solder layer. Melting the low melting point metal layer or the solder layer formed in,
In a package for electronic parts that performs airtight bonding, the width of the low melting point metal layer or the solder layer is formed wider than the width of the low melting point metal or the metal layer having a higher melting point than the solder formed on the ceramic substrate. It is characterized by that.

The low melting point metal layer, the solder layer and the like can be formed by a clad material obtained by a rolling method, or can be formed by various kinds of plating or the like. Since the formation by rolling does not use a binder or the like, gas emission during melting is small, and adverse effects of gas can be avoided, which is preferable.

Taking the case where the melted joint is solder as an example,
The operation and the like according to the present invention will be described. By melting the solder, the mounting position of the lid is self-corrected and positioned and fixed on the basis of the metal layer formed on the ceramic substrate. That is, by making the width of the metal layer approximately equal to that of the solder layer, or by making the width of the metal layer relatively narrow, when the solder is melted, the mounting position of the lid is set based on the metal layer formed on the ceramic substrate. It is self-corrected by surface tension and fixed in position. For example, as shown in FIG. 2, even when the lid 2 is mounted with a shift, the lid is joined at a predetermined position by a slight movement in the arrow X direction due to the surface tension when the solder is melted.

If the width of the metal layer is narrower than the width of the solder layer, that is, if the width A of the metal layer shown in FIGS. 3 and 4 is less than the width B of the solder layer, then the self-correcting action described above is completely eliminated. Even if it does not function, the bonding area (seal path width) can be secured, and therefore the reliability in bonding becomes high. Also, it is necessary to allow for some manufacturing error in the ceramic substrate,
Even when such a manufacturing error occurs, or when a manufacturing error occurs when the solder layer is formed by the rolling method, a manufacturing error occurs in the low melting point glass formation, or the like, the bonding area is the same as above. Since the (seal path width) can be secured, the reliability in joining is increased. If the width of the solder layer is larger than the width of the metal layer, the released gas when the solder is melted is likely to be accumulated inside the package, which is a point to be considered in designing.

As a method of manufacturing the electronic component package as described above, the manufacturing method as set forth in claim 2 can be cited. That is, a ceramic base, a metal layer having a melting point higher than that of a low-melting metal or solder formed of at least one layer circumferentially formed around the main surface of the ceramic base, and a low-melting metal or solder formed on the ceramic base. An electronic component including a low-melting metal layer or a solder layer, which is bonded to a metal layer having a higher melting point, is formed in a circumferential shape, and a lid for performing airtight bonding by melting the low-melting metal layer or the solder layer. A method for manufacturing a package for use, comprising: forming a width of a low melting point metal or solder layer formed on the lid wider than a width of the metal layer; and melting the low melting point metal or solder formed on the ceramic substrate. A step of mounting the lid by associating a low melting point metal layer or a solder layer formed on the lid on the upper surface of a metal layer having a high temperature, and a ceramic on which the lid is mounted. The ambient temperature of the body is set as the melting temperature of the low melting point metal layer or the solder layer, the low melting point metal layer or the solder layer is melted, and the relative position of the lid with respect to the ceramic substrate is set by the surface tension of the molten solder that acts at this time. The process of self-correction, and then
And a step of hardening the low melting point metal layer or the solder layer to hermetically bond the low melting point metal layer or the solder layer, and manufacturing the package for electronic parts.

Further, as described in claim 3, a ceramic substrate, and a first low-melting-point glass layer or an alumina coating layer which is formed circumferentially around the main surface of the ceramic substrate,
A second low-melting-point glass layer bonded to correspond to the first low-melting-point glass layer or the alumina coating layer, and a lid formed in a circumferential shape, and the first and second low-melting-point glasses are provided at ambient temperatures. A package for an electronic component that performs airtight bonding by setting a layer melting temperature, wherein a width of the second low melting point glass layer is formed to be wider than a width of the first low melting point glass layer or the alumina coat layer. It may be configured as

With this configuration, the same modifications and effects as in the case of using the low melting point metal or the solder joint according to claim 1 can be obtained as described above, and the emission gas is generated as compared with the solder or the like. Since the number is small, it does not adversely affect the electronic elements housed inside the package.

As a manufacturing method using a low melting point glass,
A ceramic substrate, a first low melting point glass layer or an alumina coating layer formed circumferentially around a main surface of the ceramic substrate, and the first low melting point glass layer or an alumina coating, as set forth in claim 4. A method for manufacturing an electronic component package, comprising: a second low-melting point glass layer, which is joined to correspond to a layer, is formed in a circumferential shape, and a lid for performing airtight bonding by melting the low-melting point glass layer. Forming the width of the second low melting point glass layer wider than the width of the first low melting point glass layer or alumina coat layer;
The step of mounting the lid on the upper surface of the first low melting point glass layer or the alumina coating layer in correspondence with the second low melting point glass layer, and the ambient temperature of the ceramic substrate on which the lid is mounted are set to the first And the melting temperature of the second low-melting glass layer, the first and second low-melting glass layers are melted, and the relative position of the lid with respect to the ceramic substrate is self-corrected by the surface tension of the molten glass acting at this time. And a step of subsequently lowering the ambient temperature to cure the first and second low-melting-point glass layers to perform airtight bonding, and a method of manufacturing an electronic component package. You can

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. 1, 2, 3 and 4 by taking a surface mount type crystal resonator as an example. 1 is an internal cross-sectional view showing the present embodiment, FIG. 2 is a view showing an example in which a lid is slightly moved by a self-correcting action, FIG. 3 is a plan view of a ceramic package, and FIG. 4 is a rear plan view of the lid. is there. The basic structure is as shown in FIG. 1, and a concave ceramic package 1 having an opening at the top, a crystal vibrating plate 3 which is an electronic element housed in the package, and an opening portion of the package are joined. And a lid 2 made of metal.

Ceramic package 1 having a concave shape in cross section
Consists of a ceramic substrate 10 and a circumferential metal layer 11 formed in the opening around the concave shape. The metal layer 11 includes a metallized layer 11a made of tungsten or the like, a lower plated layer 11b made of nickel or the like formed on the metallized layer, and an upper plated layer 11c made of gold or the like formed on the lower plated layer. Consists of. In this embodiment, the thickness of each layer is 18 to 20 μm for the metallized layer 11, 6 μm for the lower plating 12, and 1 μm for the upper plated layer 13.

Electrode pads 12 and 13 are formed on the inner bottom surface of the ceramic package 1, and these electrode pads are electrically connected to the bottom surface outside the package as lead electrodes 16 and 17 via the connecting electrodes 14 and 15. Have been pulled out. A rectangular crystal diaphragm 3 which is an electronic element is mounted between the electrode pads 12 and 13. Although not shown, a pair of excitation electrodes are formed on the front and back surfaces of the crystal diaphragm 3, which are led out to the electrode pads 12 and 13, respectively, and conductively bonded by the conductive bonding materials S1 and S2.

As shown in FIGS. 3 and 4, the lid 2 for hermetically sealing has a circumferential solder layer 21 corresponding to the circumferential metal layer 11 formed on the lower surface of a metal base material 20 such as Kovar. There is.
The lid 2 may use a ceramic plate instead of a metal material. The solder layer 21 is formed by, for example, a rolling method, but a plating method or the like may be used.
In this embodiment, the width of the metal layer 11 is equal to the width of the solder layer 1
The width of 2 is set wide. More specifically, the outer dimensions of the ceramic package are 3.2 mm in length, 2.5 mm in width, 0.7 mm in height, and the outer dimensions of the lid are 3.1 mm in length and 2.4 m in width.
m, height (thickness) 0.1 mm, width of metal layer 0.5 mm, width of solder layer 0.7 mm, and solder layer extends 0.2 mm inside the package.

In the case of hermetically sealing, the lid 2 and the metal layer of the ceramic package 1 are superposed on each other and the ambient temperature is melted to the solder melting temperature and melted. More specifically, the solder is melted by passing through a reflow oven set to the melting temperature of the formed solder. Due to this melting, the mounting position of the lid is positioned by self-correction with reference to the metal layer formed on the ceramic substrate. As described above, even when the lid 2 is displaced and mounted as shown in FIG. 2, for example, when the solder is melted, the lid is slightly moved in the direction of the arrow X and the lid is positioned at a predetermined position. Fixed.

Another example of the embodiment according to the present invention will be described with reference to FIG. 5, taking a surface mount type crystal resonator as an example. In this example, airtight bonding is performed using low melting point glass.
The basic structure is similar to the structure shown in the above-described embodiment, and a concave ceramic package 4 having an open top, a crystal diaphragm 6 as an electronic element housed in the package, and a package The lid 5 is joined to the opening of the.

Ceramic package 4 which is concave in cross section
Is composed of a ceramic substrate 40 and a peripheral low-melting-point glass layer 41 formed in an opening around the concave shape. In addition, electrode pads 42, 4 are provided on the inner bottom surface of the ceramic package 4.
3 (43 is not shown) are formed, and these electrode pads are electrically led out as lead-out electrodes 45 and 46 to the bottom surface outside the package through the connecting electrode 44 and the like. A rectangular crystal vibrating plate 6, which is an electronic element, is mounted between the electrode pads 42 and 43, and one end in the longitudinal direction is cantilevered. Although not shown, a pair of excitation electrodes are formed on the front and back surfaces of the crystal vibrating plate 6 and are drawn out to the electrode pads 42 and 43 side, respectively, and the conductive bonding material S1 is formed.
Are electrically conductively joined together.

The lid 5 for hermetically sealing the peripheral low melting point glass layer 41 on the lower surface of a ceramic plate made of alumina or the like.
A peripheral low-melting-point glass layer 51 corresponding to is formed.
In this embodiment, the width of the low melting point glass layer 51 is set larger than the width of the low melting point glass layer 41.

When airtight sealing is performed, the low melting point glass layers are superposed and the ambient temperature is set to the low melting point glass melting temperature to melt them. More specifically, the low melting glass is melted by passing through a reflow furnace set to the melting temperature of the formed low melting glass layer. By this melting, the mounting position of the lid is positioned by self-correcting.

Instead of the low melting point glass layer 41 formed on the package side, an alumina coat layer narrower than the low melting point glass layer 51 may be used.

Although the present invention exemplifies the surface mount type crystal unit, the present invention may be applied to a package for a piezoelectric filter or a piezoelectric oscillator, and may be applied to other electronic parts requiring hermetic sealing. You may apply.

[0034]

According to the present invention, the mounting position of the lid is self-corrected and positioned and fixed by the melted joint. Therefore, the airtight joining can be performed without the need for a positioning jig for joining, which is required in the conventional airtight joining method.
Therefore, it is possible to achieve good airtight bonding even in an extremely small package for electronic components. In addition, since it is possible to perform airtight bonding without making mechanical contact with individual packages, it is possible to perform airtight sealing of a large number of electronic components at once and obtain airtight bonding with excellent productivity. You can

According to the first aspect, since the solder is formed by the rolling method, the gas emission at the time of melting the solder is small, and the adverse effect on the electronic element inside the package can be minimized. Therefore, the reliability of the electronic component is improved such that the change with time as the electronic component is stabilized.

According to the third aspect, since the low melting point glass is used for the joint portion, there are advantages that the released gas at the time of joining is small and the reliability of the electronic component is improved, such as a stable change over time as the electronic component. Have

According to the second and the fourth aspects, the ambient temperature is set to the melting temperature of the solder or the low melting point glass, and the melting of the solder layer or the low melting point glass layer formed on the lid is promoted, whereby the relative tension of the lid is caused by the surface tension. Since the position is self-corrected, efficient manufacturing can be performed.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a movement state of a lid according to the first embodiment.

FIG. 3 is a plan view of a ceramic package.

FIG. 4 is a plan view seen from the back surface of the lid.

FIG. 5 is an internal cross-sectional view showing another embodiment.

FIG. 6 is a diagram showing a conventional example.

[Explanation of symbols]

1,4 ceramic package 10, 40 Ceramic substrate 11,41 Metal layer 11a metallized layer 11b Lower plating layer 11c Upper plating layer 2,5 lid 20 Metal base material 21 Solder layer 3, 6 Crystal diaphragm (electronic component element)

Continuation of front page (56) Reference JP-A-9-246415 (JP, A) JP-A-1-278959 (JP, A) JP-A-3-116760 (JP, A) JP-A-9-260998 (JP , A) JP-A-5-226492 (JP, A) JP-A-6-140866 (JP, A) JP-A-6-196577 (JP, A) JP-A-8-46075 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H03H 3/02 H03H 9/02 H03H 9/10 H01L 23/02

Claims (4)

(57) [Claims] 1. A low melting point metal or a metal layer having a melting point higher than that of a solder, which is composed of a ceramic substrate and at least one layer formed circumferentially around a main surface of the ceramic substrate, and a low melting point formed on the ceramic substrate. Metal or solder
A low melting point metal layer or a solder layer joined to correspond to a metal layer having a higher melting point and a lid formed in a circumferential shape, and by setting the ambient temperature to the melting temperature of the low melting point metal layer or the solder layer, A package for an electronic component that performs airtight bonding by melting the low melting point metal layer or the solder layer formed on the lid
A chromatography di, width of the low melting point metal layer or the solder layer the ceramic
Higher melting point than low melting point metal or solder formed on the substrate
Electronic component package, characterized in that it is wider than the width of the metal layer are. 2. A ceramic substrate, a low melting point metal or a high melting point metal layer of solder consisting of at least one layer formed on the principal surface around the ceramic base circumferentially, said cell
Melting from low melting point metal or solder formed on the Lamic substrate
For an electronic component comprising a low melting point metal layer or a solder layer to be joined corresponding to a metal layer having a high point formed in a circumferential shape, and a lid for hermetically joining by melting the low melting point metal layer or the solder layer A method of manufacturing a package, comprising: forming a low melting point metal or solder layer formed on the lid to have a width wider than that of the metal layer ; and a low melting point metal or solder formed on the ceramic substrate.
A step of mounting the lid on the upper surface of a metal layer having a higher melting point by associating a low melting point metal layer or a solder layer formed on the lid, the ambient temperature of the ceramic substrate on which the lid is mounted being set to the low melting point metal; The melting temperature of the layer or the solder layer, the low melting point metal layer or the solder layer is melted, and the relative position of the lid with respect to the ceramic substrate is self-corrected by the surface tension of the molten solder acting at this time; A method for manufacturing an electronic component package, comprising the steps of lowering an ambient temperature and curing a low melting point metal layer or a solder layer formed on the lid to perform airtight bonding. 3. A ceramic base, and a first peripherally formed peripheral surface of the ceramic base.
Of the low melting point glass layer or the alumina coating layer, and a lid having a second low melting point glass layer bonded to correspond to the first low melting point glass layer or the alumina coating layer in a circumferential shape. A package for an electronic component, which performs airtight bonding by setting a temperature to a melting temperature of the first and second low melting point glass layers, wherein a width of the second low melting point glass layer is the first low melting point glass layer. Alternatively, the electronic component package is formed wider than the width of the alumina coat layer . 4. A ceramic substrate, a first low melting point glass layer or an alumina coating layer formed circumferentially around the main surface of the ceramic substrate, and the first low melting point glass layer or the alumina coating layer. A method for manufacturing an electronic component package, comprising: a second low-melting-point glass layer to be joined in a circumferential shape; and a lid for performing airtight bonding by melting the low-melting-point glass layer. Forming a width of the second low-melting-point glass layer wider than that of the first low-melting-point glass layer or the alumina coat layer ; and forming the second low-melting glass layer on the upper surface of the first low-melting-point glass layer or the alumina coat layer. The step of mounting the lid in correspondence with the melting point glass layer, and the ambient temperature of the ceramic substrate on which the lid is mounted
The melting temperature of the first and second low-melting glass layers is set to melt the first and second low-melting glass layers, and the relative position of the lid with respect to the ceramic substrate is determined by the surface tension of the molten glass that acts at this time. A method of manufacturing a package for electronic parts, comprising: a step of self-correcting; and a step of subsequently lowering the ambient temperature to cure the first and second low melting point glass layers to perform airtight bonding.