JP3831937B2 - Package for electronic components - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component package that accommodates an electronic component such as a piezoelectric element.
[0002]
[Prior art]
Conventionally, as a surface-mount type piezoelectric device, a piezoelectric element such as a crystal resonator is accommodated inside a container made of an insulating material such as ceramics, and the inside of the container is hermetically sealed using a metal lid. Is generally known.
As shown in FIG. 5, when a lid is joined to the opening frame of the container 62 containing the piezoelectric element x, a metal layer 63 such as tungsten or molybdenum is formed on the upper end surface 62a of the opening frame of the container (metallized). On the other hand, clad lead-tin eutectic solder, gold-tin eutectic solder or the like is attached to the joint surface of the lid 64 with the opening frame of the container as the brazing material 65, and these are attached. By superimposing and heating, both are joined and the inside of the container is hermetically sealed.
However, when a container with a narrow seal path and a lid are joined using solder for brazing as a brazing material, due to fluctuations in the sealing conditions such as temperature and load when the brazing material is heated and melted, voids are trapped in the brazing material. When it generate | occur | produces, there exists a problem of causing the short circuit defect of a piezoelectric element etc. because the joining strength between a container and a cover falls or a brazing material hangs down inside a container.
For this reason, in the invention described in Japanese Patent Application Laid-Open No. 2000-294664, a lower metal layer is formed on the end face of the opening frame of the container, and an upper metal layer having a width narrower than the lower metal layer is provided on the lower metal layer. A solder pool portion is formed between the convex portion formed by the above and the lid. According to this, since the brazing material is stored in the brazing material reservoir portion and does not sag into the accommodation space of the piezoelectric element and has no voids, it prevents the occurrence of short-circuit failure and the bonding area. This increases the joint strength and improves the airtight reliability. Note that the thickness (height) of the metal layer at this time is 30 μm for both the lower layer and the upper layer according to Japanese Patent Laid-Open No. 2000-294664, and shrinkage of about 10% occurs due to firing, so the actual thickness is about 27 μm. It becomes a metal layer.
[0003]
[Problems to be solved by the invention]
By the way, with recent miniaturization of electronic devices, there is a strong demand for miniaturization of mounted parts, and miniaturization of piezoelectric devices is also being promoted. When the entire size is reduced in this way, the width W of the opening frame of the container must be reduced accordingly, as shown in FIG. 5, and particularly when one side L of the container becomes 5 mm or less, The width W of the opening frame of the container must be 0.4 mm or less.
However, if the width W of the opening frame is made as thin as 0.4 mm or less while the height of the metal layer formed on the upper end surface of the opening frame of the container is kept at 30 μm for both upper and lower layers as in the conventional case, poor bonding is likely to occur. Become. That is, when the width W of the opening frame is secured to some extent, as shown in FIG. 6A, the fillet is correctly formed and a reliable joining state is obtained, but the wettability of the solder 20 becomes smaller as the width W becomes narrower. Or the fillet is not properly formed, and the outer solder fillet portion is recessed as shown in FIG. 6B, or the inner solder fillet portion is not as shown in FIG. 6C. It becomes indented, and it is in a state of leaking without keeping the seal.
Such a problem often occurs particularly when the high-temperature solder is melted and bonded by a short heating process using the pulse heat method. As disclosed in JP-A-11-214551, this pulse heat method is a heating method that uses Joule heat that is generated when a pulsed large current is passed through a high resistance material. If pulse heat is applied from the lid side while a load is applied between the two, heat is transferred in the order of the lid → solder → metal layer on the upper end surface of the opening frame, and the solder instantaneously melts, so the container and lid are instantly fixed. It can be made to. For this reason, when it is not desired to damage parts in the container due to heating, this pulse heat method must be adopted, and measures for eliminating the above-described problems are required.
The present invention has been made in view of the above, prevents the brazing material from sagging at the joint between the container and the lid, and does not cause joint failure in the joint caused by downsizing of the package. The object is to provide a package for electronic parts with a high yield rate.
[0004]
In order to solve the above-mentioned problem, the invention according to claim 1 includes: a box-shaped container having an open upper surface for accommodating an electronic component; and a lid that is in close contact with the upper end of the opening frame of the container and seals the inside of the container. In the electronic component package provided, a metal layer is formed on an upper end surface of the opening frame, and the metal layer has a convex portion upward, and the width of the opening frame is set to 0.4 ±. 0.1 mm, the width of the convex portion is 0.15 ± 0.05 mm, the height of the convex portion is 5 to 20 μm, and the lid has a metal surface at least at a portion joined to the opening frame. Then, a brazing material is clad on the metal surface of the lid, the brazing material is joined between the metal layer of the container and the metal surface of the lid, and the metal layer of the container and the metal surface of the lid It is characterized by being joined by a pulse heating type heating method.
According to a second aspect of the present invention, there is provided an electronic component package comprising: a box-shaped container having an open upper surface for accommodating an electronic component; and a lid that is in close contact with the upper end of the opening frame of the container and seals the inside of the container. In this case, a metal layer is formed on the upper end surface of the opening frame, and the metal layer has a convex portion on the upper side, and the width of the opening frame is set to 0.4 ± 0.1 mm. The width of the portion is 0.15 ± 0.05 mm, the height of the convex portion is 10 to 15 μm, the lid has a metal surface at least at a portion joined to the opening frame, and the metal surface of the lid And brazing the brazing material, joining the metal layer of the container and the metal surface of the lid with the brazing material, and a pulse heat system between the metal layer of the container and the metal surface of the lid It is characterized by being joined by the heating method.
According to a third aspect of the present invention, there is provided an electronic component package comprising: a box-shaped container having an open upper surface for accommodating an electronic component; and a lid that is in close contact with the upper end of the opening frame of the container and seals the inside of the container. In this case, a first metal layer is provided on the upper end surface of the opening frame, and a second metal layer is provided in the center in the width direction on the first metal layer. 0.4 ± 0.1 mm, the width of the second metal layer is 0.15 ± 0.05 mm, the height of the second metal layer is 5 to 20 μm, and the lid includes at least the opening frame. A metal surface at a portion to be joined, and brazing a brazing material on the metal surface of the lid, joining the metal layer of the container and the metal surface of the lid with the brazing material, The metal layer of the container and the metal surface of the lid are joined by a pulse heat type heating method.
According to a fourth aspect of the present invention, there is provided an electronic component package comprising: a box-shaped container having an open upper surface for accommodating an electronic component; and a lid that is in close contact with the upper end of the opening frame of the container and seals the inside of the container. In this case, a first metal layer is provided on the upper end surface of the opening frame, and a second metal layer is provided in the center in the width direction on the first metal layer. 0.4 ± 0.1 mm, the width of the second metal layer is 0.15 ± 0.05 mm, the height of the second metal layer is 10 to 15 μm, and the lid includes at least the opening frame. A metal surface at a portion to be joined, and brazing a brazing material on the metal surface of the lid, joining the metal layer of the container and the metal surface of the lid with the brazing material, The metal layer of the container and the metal surface of the lid are joined by a pulse heat type heating method.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a side cross-sectional view showing a structure of an electronic component package used in a one-end fixed surface mount piezoelectric device according to a first embodiment.
The surface-mount type piezoelectric device includes a crystal resonator X as an electronic component and an electronic component package (hereinafter referred to as a package) 1 that accommodates the crystal resonator X. The package 1 includes a box-shaped container 2 having an open upper surface that accommodates the crystal unit X, and a lid member 3 that hermetically seals the accommodating space 12 in the container 2. The container 2 is made of alumina, and includes a plate member 4 constituting a bottom portion and a frame member 5 provided on the plate member 4 so as to be laminated to constitute a trunk portion. Metal layers 10 and 11 as joint portions are provided on the end portion of the frame member 5 on the side not integrally coupled with the plate member 4, that is, the upper end surface 5 a of the opening frame of the container 2. An insulating film 6 is provided between the plate member 4 and the frame member 5, and a part of the insulating film 6 is exposed inside the container 2.
Of the exposed insulating film 6, a pair of fixed electrodes 7 are provided on the surface of one insulating film 6 corresponding to one end Xa of the crystal resonator X, and the other corresponding to the other end Xb of the crystal resonator X. The insulating film 6 is located below the free end of the crystal unit X. The other insulating film 6 acts as a pillow member that absorbs vibration, impact, etc. of the crystal resonator X by limiting the displacement of the free end of the crystal resonator X.
The fixed electrode 7 is electrically connected to a lead electrode (not shown) formed on the crystal unit X by a conductive adhesive 8 or the like, holds the crystal unit X in a cantilever state, and is attached to the back surface of the plate member 4. The connection electrode 9 for mounting on the provided printed circuit board or the like is in an electrically conductive state.
The metal layers 10 and 11 are joined to the lid 3 by a brazing material 20, and the lid 3 hermetically seals the accommodation space 12. The metal layers 10 and 11 are made of a metal material such as tungsten or molybdenum. The lower metal layer 10 is formed on the entire upper end surface of the frame member 5, and the metal layer 11 is formed with a width smaller than that of the metal layer 10 at the center of the upper surface in the width direction. The metal layer 10 and the metal layer 11 form a convex portion. Nickel plating or gold plating is applied to the surface of the two metal layers.
The brazing material 20 is made of sealing solder such as gold-tin solder, and the lid 3 is made of a metal material such as Kovar or 42 alloy. When the lid 3 is joined to the container 2, a brazing material reservoir 21 is formed in the gap between the metal layer 10 and the lid 3.
In the electronic component package having the above-described structure, the brazing material 20 is stored in the brazing material reservoir portion 21 and does not sag into the accommodation space 12, and has no voids. For this reason, it is possible to prevent occurrence of short-circuit failure, increase the bonding area, increase the bonding strength between the package 2 and the lid member 3, and improve the airtight reliability.
[0006]
FIG. 2 is an enlarged cross-sectional view showing the configuration of the joint. When the outer width of the package 1, that is, the width of one side of the container 2 is 5 mm or less, the width W of the frame member 5 is preferably 0.4 mm. To ensure a certain amount of internal volume while reducing the size of the package, it is necessary to reduce the frame width of the container. However, if the thickness is too small, the frame wall will crack and airtightness will not be maintained, causing a problem in strength. . In consideration of this, the width W of the frame member 5 is suitably about 0.4 mm, and the width of the metal layer 10 provided on the upper end surface of the frame member 5 is accordingly about 0.4 mm.
The thickness of the sealing solder 20 clad on the lid 3 is 30 μm. If it is thinner than this, the number of rolling operations during processing increases, resulting in high costs. On the other hand, if it is thicker than this, the amount of solder increases, which is expensive. Accordingly, a material having a thickness of 30 μm is standard regardless of the size of the lid 3 in view of cost.
The width w of the upper metal layer 11 provided at the center in the width direction on the metal layer 10 is set to about 0.15 mm, and the height h is set to 5 to 20 μm. When the convex portion made of the metal layers 10 and 11 having such dimensions and the lid member 3 are joined by the brazing material 20, the fillet is correctly formed, the joining state is good, and the seal path is narrow. However, the bonding strength is also maintained, and the lid member 3 hermetically seals the housing space 12.
[0007]
FIG. 3 is a graph showing a non-defective product ratio with respect to a change in the height of the upper metal layer 11 (hereinafter referred to as a protrusion). It shows how the joining state of the container 1 and the lid 2 changes depending on the change in the height of the protrusion. In the experiment, the number of samples was 31, and gold-tin solder was used as a brazing material, and the sample was heated at a heating temperature of 320 ° C. for about 2 seconds by a pulse heat method. Further, the non-defective product was judged by visually observing the state of the fillet, observing the cross section of the joint with a magnifying glass, and confirming the sealing performance by a leak test. The width W of the frame member 5 is 0.4 mm, and the width w of the protrusion is 0.15 mm.
According to this, when the height h of the protrusion is in the range of 5 to 20 μm, the yield rate is 95% or more, and particularly when the height of the protrusion is 10 to 15 μm, the yield rate is 100%. . However, when the height of the protrusion was 0 μm (no protrusion), the yield rate was 81%, and when the height of the protrusion was 28 μm, the yield rate was 74%. Even when the width W of the frame member 5 is changed to 0.4 ± 0.1 mm, the same result as described above is obtained, and the same is true when the protrusion width is 0.15 ± 0.05 mm. Become.
This is because if the protrusions are high, heat is not easily transmitted to the entire metal layers 10 and 11, and it is considered that solder wetting is poor, resulting in poor bonding. Conversely, if the protrusions are low, the accumulation of solder is reduced. It is considered that the amount of solder is insufficient, which causes bonding failure, and the above results can be said to indicate that the optimum conditions for protrusions that can solve both problems were experimentally obtained.
As described above, when the width W of the frame member 5, in other words, the width W of the upper end surface of the opening frame of the container 2 is 0.4 mm ± 0.1 mm, the width of the protrusion made of the metal layer 11 is 0.15. If the height of the projection is set to ± 0.05 mm and the height of the protrusion is set to 5 to 20 μm, a leak defect is generated as compared with the case where the height of the metal layer formed on the upper end surface of the conventional container opening frame is set to 30 μm on both upper and lower layers. Can be prevented, the bonding strength between the package 2 and the lid member 3 can be increased, and the yield rate is extremely increased. Therefore, the airtight reliability can be improved with a simple configuration, particularly in a small package having a narrow seal path.
Note that not only gold-tin solder, but also a brazing material having a melting point of 250 ° C. or higher, even when joining by a short heating process using a pulse heat method, the structure of the joint as described above is used. If so, the fillet is correctly formed, and a reliable joining state can be achieved without damaging the components in the container due to heating.
[0008]
FIG. 4 is an enlarged cross-sectional view illustrating a configuration of a joint portion of the electronic component package according to the second embodiment. In addition, the same code | symbol is attached | subjected to the component substantially the same as 1st Embodiment.
In the second embodiment, a stepped portion 51 is formed at the upper end portion of the frame member 5, and the stepped portion 51 is formed and the metal layer 40 is provided on the upper end surface. The surface of the metal layer 40 is plated with nickel or gold or both. When the lid 3 is joined to the container 2, the brazing material reservoir portion 21 is formed in the gap between the metal layer 40 and the lid 3.
The step portion 51 is formed by processing a plurality of ceramic green sheets to be the frame member 50 using a punching die or a punching machine so that the outer shape of the upper green sheet is smaller than the outer shape of the lower green sheet. After being laminated, it can be easily formed by firing and integrating.
The width W of the frame member 5 is about 0.4 mm, the width w of the upper portion of the metal layer 40 formed at the end of the step portion 51 is about 0.15 mm, and the height h is set to 5 to 20 μm. To do. In the case where the step portion 51 and the convex portion formed of the metal layer 40 and the lid member 3 are joined by the brazing material 20 with such dimensions, the fillet is correctly formed and the joining state is good, and the narrow seal path However, the bonding strength is also maintained, and the lid member 3 hermetically seals the housing space 12.
As described above, in the second embodiment, when the width W of the frame member 5, in other words, the width W of the upper end surface of the opening frame of the container 2 is 0.4 mm ± 0.1 mm, If the width of the protrusion made of the metal layer to be formed is set to 0.15 ± 0.05 mm and the height of the protrusion is set to 5 to 20 μm, it is possible to prevent the occurrence of a leak defect as in the first embodiment. The bonding strength with the lid member 3 can be increased, and the yield rate is extremely increased.
[0009]
In the above-described embodiments, gold-tin solder is used as the brazing material. However, the present invention is not limited to this, and any solder that has a melting point of 250 ° C. or higher can be applied.
In the above-described embodiments, the housing space 12 is hermetically sealed by the metal lid member 3. However, in the present invention, the ceramic lid in which the conductive paste is printed and fired at the place to be the sealing portion. The housing space may be hermetically sealed by the member.
In the above-described embodiments, the present invention is applied to an alumina package. However, the present invention is not limited to alumina, but is applied to a package made of ceramic such as aluminum nitride, mullite, glass, or other insulating materials. May be.
Further, in the above-described embodiments, the present invention is applied to the single-end fixed surface mount type piezoelectric device, but it is needless to say that the present invention can be applied to both end fixed type surface mount type piezoelectric devices.
In the above-described embodiments, the surface-mounted crystal resonator is described as an example of the piezoelectric element. However, the present invention is not limited to this, and lithium tantalate, lithium niobate, lithium tetraborate or The present invention can also be applied to a resonator or a filter using a piezoelectric vibrator, a surface acoustic wave element, or the like made of piezoelectric ceramic.
Further, in the above-described plurality of embodiments, the case where the piezoelectric element is accommodated alone in the package has been described as an example. However, the present invention is not limited to this, and the oscillation of an IC or the like together with the piezoelectric element is included in the package. You may apply to electronic components, such as an oscillator comprised with the circuit, or electronic components, such as a semiconductor element and a chip capacitor.
[0010]
【The invention's effect】
As described above, according to the present invention, an electronic component comprising a box-shaped container having an open upper surface for accommodating an electronic component, and a lid that tightly contacts the upper end of the opening frame of the container and seals the inside of the container. And a container having a first metal layer formed on an upper end surface of the opening frame of the container and a second metal layer provided at a center in the width direction on the first metal layer, Since the width of the opening frame is 0.4 ± 0.1 mm, the width of the second metal layer is 0.15 ± 0.05 mm, and the height is 5 to 20 μm, the first and second When the convex part made of a metal layer and the lid are joined with a brazing material, the lid hermetically seals the accommodation space, the fillet is correctly formed, the joined state is good, and the seal path is narrow However, the bonding strength is maintained and the yield rate is 95% or more. It can be. Further, even when a gold-tin solder having a melting point of 250 ° C. or higher is used as a brazing material and bonding is performed by a short heating process using a pulse heat method, the fillet is formed as long as the structure of the bonding portion is as described above. It is correctly formed, and it can be in a surely joined state without damaging the components in the container by heating.
Further, the present invention provides an electronic component package comprising a box-shaped container having an upper surface that opens an electronic component, and a lid that is in close contact with the upper end of the opening frame of the container and seals the inside of the container. A first metal layer formed on an upper end surface of the opening frame, and a second metal layer provided in the center in the width direction on the first metal layer, the width of the opening frame of the container 0.4 ± 0.1 mm, the width of the second metal layer is 0.15 ± 0.05 mm, and the height thereof is 10 to 15 μm. A result that the yield rate is 100% can be obtained.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing a structure of an electronic component package according to a first embodiment.
FIG. 2 is an enlarged cross-sectional view illustrating a configuration of a joint portion.
FIG. 3 is a graph showing a non-defective rate of a package with respect to a change in the height of a metal layer 11 (protrusions).
FIG. 4 is an enlarged cross-sectional view illustrating a configuration of a joint portion in an electronic component package according to a second embodiment.
FIG. 5 is a view showing the structure of a conventional electronic component required package.
FIG. 6 is a view showing a fillet formation state in a conventional package.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Package for electronic components, 2 container, 3 lid | cover, 4 board member, 5 frame member, 6 insulating film, 7 fixed electrode, 8 conductive adhesive, 9 connection electrode, 10, 11 metal layer (joining part), 12 accommodation Space, 20, 30 Brazing material, 21, 31 Brazing material reservoir part, 40 Metal layer (joining part), 51 Step part

Claims (4)

In an electronic component package comprising a box-shaped container having an open upper surface for accommodating an electronic component, and a lid that is in close contact with the upper end of the opening frame of the container and seals the inside of the container.
A metal layer is formed on the upper end surface of the opening frame, and the metal layer has a convex portion on the upper side,
The width of the opening frame is 0.4 ± 0.1 mm,
The width of the convex portion is 0.15 ± 0.05 mm,
The height of the convex portion is 5 to 20 μm,
The lid has a metal surface at least at a portion joined to the opening frame,
Brazing a brazing material on the metal surface of the lid, and joining the metal layer of the container and the metal surface of the lid with the brazing material,
A package for electronic parts, wherein a metal layer of the container and a metal surface of the lid are joined by a heating method of a pulse heat system. In an electronic component package comprising a box-shaped container having an open upper surface for accommodating an electronic component, and a lid that is in close contact with the upper end of the opening frame of the container and seals the inside of the container.
A metal layer is formed on the upper end surface of the opening frame, and the metal layer has a convex portion on the upper side,
The width of the opening frame is 0.4 ± 0.1 mm,
The width of the convex portion is 0.15 ± 0.05 mm,
The height of the convex part is 10 to 15 μm,
The lid has a metal surface at least at a portion joined to the opening frame,
Brazing a brazing material on the metal surface of the lid, and joining the metal layer of the container and the metal surface of the lid with the brazing material,
A package for electronic parts, wherein a metal layer of the container and a metal surface of the lid are joined by a heating method of a pulse heat system. In an electronic component package comprising a box-shaped container having an open upper surface for accommodating an electronic component, and a lid that is in close contact with the upper end of the opening frame of the container and seals the inside of the container.
A first metal layer is provided on the upper end surface of the opening frame, and a second metal layer is provided at the center in the width direction on the first metal layer,
The width of the opening frame is 0.4 ± 0.1 mm,
The width of the second metal layer is 0.15 ± 0.05 mm,
The height of the second metal layer is 5 to 20 μm,
The lid has a metal surface at least at a portion joined to the opening frame,
Brazing a brazing material on the metal surface of the lid, and joining the metal layer of the container and the metal surface of the lid with the brazing material,
A package for electronic parts, wherein a metal layer of the container and a metal surface of the lid are joined by a heating method of a pulse heat system. In an electronic component package comprising a box-shaped container having an open upper surface for accommodating an electronic component, and a lid that is in close contact with the upper end of the opening frame of the container and seals the inside of the container.
A first metal layer is provided on the upper end surface of the opening frame, and a second metal layer is provided at the center in the width direction on the first metal layer,
The width of the opening frame is 0.4 ± 0.1 mm,
The width of the second metal layer is 0.15 ± 0.05 mm,
The height of the second metal layer is 10 to 15 μm,
The lid has a metal surface at least at a portion joined to the opening frame,
Brazing a brazing material on the metal surface of the lid, and joining the metal layer of the container and the metal surface of the lid with the brazing material,
A package for electronic parts, wherein a metal layer of the container and a metal surface of the lid are joined by a heating method of a pulse heat system.

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