JP4028808B2 - Electronic component storage package - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component storage package in which an electronic component such as a piezoelectric vibrator or a semiconductor element is hermetically accommodated in a package composed of an insulating base such as ceramics and a metal lid.
[0002]
[Prior art]
Electronic parts such as piezoelectric vibrators and semiconductor elements are housed and used in an electronic part housing package for hermetically housing these electronic parts.
[0003]
In such an electronic component storage package that stores the electronic component in an airtight manner, the most reliable one is made of ceramics such as an aluminum oxide sintered body, and the mounting portion on which the electronic component is mounted on the upper surface An insulating base having a frame-like sealing metallization layer surrounding the mounting portion and having a plurality of metallized wiring conductors to which electrodes of electronic components are electrically connected on the surface and inside, and a metallization for sealing the insulating base Metal frame for sealing made of iron-nickel alloy or iron-nickel-cobalt alloy brazed so as to surround the mounting portion on the layer, and iron directly joined to the metal frame by seam welding -It is of a type composed of a metal lid made of nickel alloy or iron-nickel-cobalt alloy, and this type of electronic component storage package In such a case, an electronic component is mounted on the mounting portion of the insulating base, and the electrode of the electronic component and the metallized wiring conductor are electrically connected via a solder bump, a bonding wire, etc., and then sealed with the insulating base. A metal lid is placed on a metal frame for stopping, and a pair of roller electrodes of a seam welding machine are brought into contact with the outer peripheral edge of the metal lid and rolled, and a large current for welding is provided between the roller electrodes. By flowing seam and directly seam-welding the metal frame body and the metal lid body, the electronic parts are housed in an airtight manner to form an electronic device as a product.
[0004]
However, in this type of electronic component storage package, it is necessary to braze a metal frame for sealing to the metallization layer for sealing as a base metal for seam welding the metal lid to the insulating base, For this reason, the height of the electronic device is increased by the amount of the metal frame, and it has been difficult to reduce the thickness required for a recent electronic device. In addition, there is a problem that the metal frame is expensive.
[0005]
Therefore, in order to solve the above-described problems, the electronic component has an electronic component mounted on the upper surface and a frame-shaped sealing metallization layer surrounding the mounted portion, and the electrode of the electronic component is electrically connected to the surface and the inside. A ceramic insulating base having a plurality of metallized wiring conductors connected to each other and a metal lid having a lower surface coated with a brazing material such as a silver-copper eutectic alloy. Insulation by mounting the electronic component and electrically connecting each electrode of the electronic component to the metallized wiring conductor, and then seam welding the brazing material with the metal lid attached to the lower surface of the sealing metallized layer An electronic component storage package has been proposed in which a base body and a metal lid are joined and an electronic component is hermetically sealed inside.
[0006]
An electronic component storage package in which an electronic component is hermetically accommodated by joining a metal lid to the sealing metallization layer by seam welding via a brazing material such as silver brazing is used for sealing. Since the metallized layer and the metal lid are joined by seam welding via a brazing material, a metal frame as a base metal for welding is not required, and the height can be reduced correspondingly, and it is inexpensive. It is.
[0007]
In the conventional electronic component storage package in which the metal lid having the lower surface coated with the brazing material is joined to the sealing metallization layer of the insulating base through the brazing material by seam welding. The metallizing layer for sealing had a thickness of 10 μm or more, preferably 20 μm or more, and a plating layer such as nickel having a thickness of 5 μm or more, preferably 8 μm or more was deposited on the surface thereof. . This is because the thickness of the metallizing layer for sealing is increased to 10 μm or more and a plating layer of nickel or the like having a thickness of 5 μm or more is deposited on the surface, so that the metal lid is placed on the metallizing layer for sealing via a brazing material. The thermal shock due to the welding current applied to the sealing metallization layer and insulating substrate during seam welding is absorbed and relaxed by the thick sealing metallization layer and nickel plating layer, and the sealing metallization layer and insulating substrate This is based on the idea of preventing the occurrence of cracks.
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-223606
[Patent Document 2]
Japanese Patent Laid-Open No. 2003-31713
[Problems to be solved by the invention]
However, according to the electronic component housing package in which the thickness of the metallization layer for sealing the insulating substrate is 10 μm or more and the nickel plating layer having a thickness of 5 μm or more is deposited thereon as described above, the metallization layer for sealing Because of the large thickness, the electrical resistance of the metallizing layer for sealing becomes low, and therefore, a metal lid with a brazing material applied to the lower surface is seam welded to the metalizing layer for sealing the insulating substrate via the brazing material. When joining, a large amount of current for welding flows through the metallization layer for sealing having a low electrical resistance, and the current flowing through the metal lid is reduced. Therefore, in order to melt the brazing material applied to the metal lid well with the welding current, an extremely large welding current must be applied, and a lot of extra power is consumed. Further, there has been a problem that cracks are likely to occur in the sealing metallized layer and the insulating substrate due to the stress remaining between the insulating substrate and the lid after welding.
[0011]
As a result of various studies in view of such problems, the present inventor has been designed to accommodate an electronic component in which the metal lid is joined to the metallization layer for sealing the insulating base by seam welding as described above. In the package, the metal lid can be heated effectively by flowing a large amount of welding current through the metal lid assuming that the metallization layer for sealing has a high electric resistance, and hermetic sealing can be performed with a lower welding current. It is possible, and by applying a plating layer of nickel or the like with a thickness equal to or greater than that of the sealing metallization layer, the current flowing through the sealing metallization layer itself is reduced and heat generation of the sealing metallization layer itself is suppressed. Since the thermal stress generated during welding is effectively relieved by a thick plating layer, it was found that cracks are less likely to occur in the metallization layer for sealing and the insulating substrate after welding.
[0012]
The present invention has been devised based on such knowledge, and its purpose is to achieve a lower welding current when a metal lid is joined to a metallization layer for sealing an insulating substrate through a brazing material by seam welding. An object of the present invention is to provide a highly reliable electronic component storage package that can be hermetically sealed and does not cause cracks in the metallization layer for sealing or the insulating substrate.
[0013]
[Means for Solving the Problems]
The electronic component storage package of the present invention includes an insulating base having a mounting portion on which an electronic component is mounted on the upper surface, a sealing metallization layer attached so as to surround the mounting portion, and a brazing material on the lower surface. An electronic component storage package comprising a metal lid bonded to the sealing metallization layer by seam welding to the sealing metallization layer, wherein the sealing metallization layer has a thickness of 4 to It has a thickness of 8 μm, and a nickel layer and a palladium layer sequentially deposited on the surface thereof, and a plating layer having a thickness of 8 to 20 μm is deposited.
[0014]
The electronic component storage package of the present invention is characterized in that the palladium layer has a thickness of 3 μm or less.
[0015]
According to the electronic component storage package of the present invention, the metallization layer for sealing has a thickness as thin as 4 to 8 μm, and comprises a nickel layer and a palladium layer sequentially deposited thereon, and has a thickness. Since the plating layer of 8 to 20 μm is deposited, the electrical resistance of the metallization layer for sealing becomes high, and when the metal lid is seam welded to the metallization layer for sealing via the brazing material, Since a large amount of current flows through the metal lid, it is possible to suppress the heat generation of the sealing metallization layer by reducing the welding current accordingly, and the brazing material between the sealing metallization layer and the metal lid. Can be welded well. In addition, the thermal stress applied to the sealing metallization layer and the insulating base during welding can be satisfactorily absorbed by the plating layer having a thickness of 8 to 20 μm applied to the sealing metallization layer. Further, it is possible to effectively prevent the occurrence of cracks due to thermal stress during welding in the metallizing layer for sealing and the insulating substrate.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, an electronic component storage package according to the present invention will be described with reference to the accompanying drawings.
[0017]
FIG. 1 is a cross-sectional view showing an example of an embodiment of an electronic component storage package according to the present invention, in which 1 is an insulating base, 2 is a metal lid, and 3 is an electronic component. Then, an electronic component 3 such as a piezoelectric vibrator or a semiconductor element is hermetically sealed inside a package composed of the insulating base 1 and the metal lid 2 to provide an electronic device as a product.
[0018]
The insulating base 1 is a support for supporting the electronic component 3 and is made of ceramics such as an aluminum oxide sintered body or an aluminum nitride sintered body, and is used for housing the electronic component 3 in the center of the upper surface thereof. A recess A is provided. The bottom surface of the recess A forms a mounting portion 1a for mounting the electronic component 3, and the electronic component 3 is mounted on the mounting portion 1a.
[0019]
If the insulating substrate 1 is made of, for example, an aluminum oxide sintered body, an appropriate organic binder and solvent are added to and mixed with ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, etc. This is made into a ceramic green sheet by adopting a conventionally known doctor blade method or calender roll method, and after that, the ceramic green sheet is appropriately punched and laminated in a plurality of layers at a high temperature. Manufactured by firing.
[0020]
Further, a metallized wiring conductor 4 made of a metal powder sintered body such as tungsten or molybdenum led out from the upper surface of the mounting portion 1 a to the lower surface of the insulating substrate 1 is deposited on the insulating substrate 1.
[0021]
The metallized wiring conductor 4 functions as a conductive path for electrically connecting each electrode of the electronic component 3 to the outside. Normally, a nickel plating layer having a thickness of about 1 to 20 μm and 0 on the exposed surface. And a gold plating layer having a thickness of about 1 to 3 μm. And the electrode of the electronic component 3 is electrically connected to, for example, the conductive adhesive 5 at a portion led out to the upper surface of the mounting portion 1a, and the portion led out to the bottom surface of the insulating base 1 is an external electric circuit It is electrically connected to the wiring conductor of the substrate via, for example, solder.
[0022]
If the metallized wiring conductor 4 is made of, for example, a tungsten powder sintered body, a tungsten paste obtained by adding and mixing an appropriate organic binder and solvent to the tungsten powder is conventionally used as a ceramic green sheet for the insulating substrate 1. A predetermined pattern is printed and applied by a well-known screen printing method, and this is baked together with the ceramic green sheet for the insulating substrate 1 to form a predetermined pattern from the upper surface to the lower surface of the mounting portion 1a of the insulating substrate 1.
[0023]
Further, on the outer peripheral portion of the upper surface of the insulating substrate 1, a frame-shaped sealing metallization layer 6 made of a metal powder sintered body such as tungsten or molybdenum and having a width of about 0.4 mm and a thickness of 4 to 8 μm is mounted. It is formed so as to surround 1a.
[0024]
This sealing metallization layer 6 functions as a base metal for joining the metal lid 2 to the insulating substrate 1, and on the exposed surface, as shown in FIG. 3, a nickel layer 9 and a palladium layer 10 are used. The plating layer 11 having a thickness of 8 to 20 μm is applied. And the metal cover body 2 is joined on it by the seam welding through the brazing material 8. FIG.
[0025]
If the metallizing layer 6 for sealing is made of, for example, a tungsten powder sintered body, a tungsten paste obtained by adding and mixing an appropriate organic binder and solvent to the tungsten powder is a ceramic green sheet for the insulating substrate 1. In this case, a screen printing method known in the prior art is used, and a predetermined thickness and pattern are preliminarily printed and applied, and this is fired together with a ceramic green sheet for the insulating substrate 1 so as to surround the mounting portion 1a on the upper surface of the insulating substrate 1. Is formed.
[0026]
On the other hand, the metal lid 2 is a flat plate made of an iron-nickel alloy plate or an iron-nickel-cobalt alloy plate and having a thickness of about 0.1 mm. The material 8 is applied to a thickness of about 10 to 20 μm. Then, as shown in a sectional view in FIG. 2, the metal lid 2 is placed on the sealing metallization layer 6 with the brazing material 8 sandwiched between them, and seam welders are placed on the opposing outer peripheral edges of the metal lid 2. The insulating substrate 1 is sealed by rolling while bringing the pair of roller electrodes R into contact with each other, passing a current for welding between the roller electrodes R, and melting a part of the brazing material 8 by heat generated by the current. The electronic component 3 is hermetically sealed with the insulating base 1 by being bonded to the metallization layer 6 for soldering via the brazing material 8.
[0027]
Such a metal lid 2 is formed by rolling an iron-nickel alloy plate or an iron-nickel-cobalt alloy plate with a brazing material foil such as silver-copper brazing on the lower surface of the iron-nickel alloy plate or iron-nickel-cobalt alloy plate. -A composite metal plate having a large area in which a brazing material is pressure-bonded to the lower surface of the cobalt alloy plate is obtained, and the composite metal plate is punched into a predetermined shape by a punching die.
[0028]
In the electronic component storage package of the present invention, the thickness of the sealing metallization layer 6 is as thin as 4 to 8 μm, and the plating layer 11 deposited on the surface of the sealing metallization layer 6 is provided. It consists of a nickel layer 9 and a palladium layer 10 which are sequentially deposited, and has a thickness of 8 to 20 μm, which is important. The thickness of the metallizing layer 6 for sealing is as thin as 4 to 8 μm, and a plating layer 11 consisting of a nickel layer 9 and a palladium layer 10 and having a thickness of 8 to 20 μm is deposited thereon. The electric resistance of the sealing metallization layer 6 to which the layer 11 is applied can be increased, and as a result, the metal lid 2 is welded to the sealing metallization layer 6 through the brazing material 8 by seam welding. In this case, since a large current flows to the metal lid 2 side, the welding current can be reduced by that amount to prevent the sealing metallization layer 6 from generating a large amount of heat and the brazing material applied to the metal lid 2. 8 can be melted satisfactorily by a welding current, and the metallizing layer 6 for sealing and the metal lid 2 can be joined well.
[0029]
In this case, since the nickel layer 9 is firmly bonded to both the sealing metallization layer 6 and the palladium layer 10, the plating layer 11 is firmly attached to the sealing metallization layer 6. be able to. Further, since the oxidation corrosion of the nickel layer 9 can be effectively prevented by the palladium layer 10, the reliability of the joining between the sealing metallized layer 6 and the metal lid 2 by welding is made more excellent. You can also.
[0030]
In addition, the palladium forming the palladium layer 10 has a higher electrical resistance than nickel (electrical resistivity (20 ° C., nickel: about 6.9 μΩ · cm, palladium: about 10.8 μΩ · cm). When the metal lid 2 is welded to the metallized layer 6 by seam welding via the brazing material 8, a large current can be surely passed to the metal lid 2 side, and the metallized layer 6 for sealing and the metal lid 2 can be joined very well.
[0031]
If the thickness of the sealing metallization layer 6 is less than 4 μm, it tends to be difficult to firmly adhere the sealing metallization layer 6 to the insulating substrate 1. When the metallization layer 6 has a low electrical resistance and the metal lid 2 is welded to the sealing metallization layer 6 via the brazing material 8 by seam welding, the current flowing to the metal lid 2 side is small. Therefore, with a small welding current, it tends to be difficult to melt the brazing material 8 attached to the metal lid 2 well. Therefore, the thickness of the metallizing layer 6 for sealing is specified in the range of 4 to 8 μm.
[0032]
Further, a roundness having a radius of about 5 to 50 μm is formed from the upper surface of the insulating substrate 1 to the outer peripheral side surface, and the outer peripheral edge of the sealing metallization layer 6 is extended so as to be gradually thinned to the middle of the rounded portion. Accordingly, it is possible to effectively prevent the sealing metallization layer 6 from being peeled off from the insulating substrate 1. Accordingly, a roundness having a radius of about 5 to 50 μm is formed from the upper surface to the outer peripheral side surface of the insulating substrate 1, and the outer peripheral edge of the sealing metallization layer 6 is extended so as to become gradually thinner to the middle of the rounded portion. It is preferable to keep it.
[0033]
Moreover, the metal paste for forming the metallizing layer 6 for sealing insulates the metallizing layer 6 having a thin thickness of 4 to 8 μm when the average particle diameter of the metal powder contained therein is 1 μm or less. The upper surface of the substrate 1 can be densely and firmly attached. Accordingly, the metal paste for the metallizing layer 6 for sealing preferably has an average particle size of the metal powder contained therein of 1 μm or less.
[0034]
Moreover, according to the electronic component storage package of the present invention, the plating layer 11 composed of the nickel layer 9 and the palladium layer 10 and having a thickness of 8 to 20 μm is deposited on the surface of the sealing metallization layer 6. Thus, when the metal lid 2 is welded to the sealing metallization layer 6 through the brazing material 8 by seam welding, the thermal stress applied to the sealing metallization layer 6 and the insulating substrate 1 is changed to the sealing metallization layer 6. 6 can be satisfactorily absorbed and relaxed by the plating layer 11 deposited on the metal plate 6. As a result, when the metal lid 2 is welded to the sealing metallized layer 6 through the brazing material 8 by seam welding and after welding. It is possible to effectively prevent cracks from occurring in the sealing metallization layer 6 and the insulating substrate 1.
[0035]
In this case, palladium forming the palladium layer 10 has lower elasticity than nickel (nickel with Young's modulus: about 2 × 10 ¹¹ N / m ² , palladium: about 1.1 × 10 ¹¹ N / m ² ). Therefore, the absorption relaxation of the thermal stress by the plating layer 11 can be made more effective.
[0036]
When the plating layer 11 made of the nickel layer 9 and the palladium layer 10 deposited on the sealing metallization layer 6 has a thickness of less than 8 μm, the metal lid 2 is brazed to the sealing metallization layer 6. When welding by seam welding through the material 8, there is a greater risk that the thermal stress applied to the sealing metallization layer 6 and the insulating substrate 1 cannot be satisfactorily absorbed and relaxed, and on the other hand, it exceeds 20 μm. In addition, cracks and peeling are likely to occur in the sealing metallized layer 6 due to stress generated when the thick plating layer 11 is formed by sequentially depositing the nickel layer 9 and the palladium layer 10. Tend to be. Therefore, the thickness of the plating layer 11 applied to the sealing metallization layer 6 is specified in the range of 8 to 20 μm.
[0037]
Further, when the thickness of the palladium layer 10 exceeds 3 μm, the residual stress in the layer becomes large, and when a thermal stress is applied during seam welding, the palladium layer 10 is formed in the palladium layer 10 or between the palladium layer 10 and the nickel layer 9. There is a possibility that mechanical destruction such as cracks may occur inside the plating layer 11 such as the interface, and the reliability of joining by welding of the metal lid 2 tends to deteriorate. Accordingly, it is preferable that the palladium layer 10 has a thickness of 3 μm or less. Further, when the thickness of the palladium layer 10 is set to 1 μm or more, the palladium layer 10 can effectively prevent the oxidative corrosion of the nickel layer 9, and the reliability as an electronic component storage package is further improved. can do. Therefore, it is more preferable that the palladium layer 10 has a thickness of 1 μm to 3 μm.
[0038]
Further, the plating layer 11 composed of the nickel layer 9 and the palladium layer 10 is oxidized and corroded when a gold plating layer (not shown) having a thickness of about 0.1 to 3 μm is deposited on the surface thereof. Can be more effectively prevented, and the reliability of the metal lid 2 can be made even better by welding. Therefore, the plating layer 11 is preferably coated with a gold plating layer on the surface thereof in a range of 0.1 to 3 μm. The gold plating layer is preferably arranged so that the crystal orientation in the X-ray diffraction is aligned with the (111) plane as much as possible. In this case, it is possible to further effectively prevent the oxidative corrosion of the plating layer 11 by increasing the atomic density of gold on the surface.
[0039]
Thus, according to the electronic component storage package of the present invention, the electronic component 3 is mounted on the mounting portion 1 a of the insulating base 1, and the metal lid 2 is seam welded to the sealing metallized layer 6 via the brazing material 8. By joining together, it is possible to provide a highly reliable electronic component storage package that does not cause disconnection in the metallized wiring conductor 4 or cracks in the insulating substrate 1.
[0040]
In addition, this invention is not limited to an example of the above-mentioned embodiment, and it cannot be overemphasized that a various change is possible if it is a range which does not deviate from the summary of this invention.
[0041]
【The invention's effect】
According to the electronic component storage package of the present invention, the sealing metallization layer has a thickness as thin as 4 to 8 μm, and is composed of a nickel layer and a palladium layer sequentially deposited thereon, and has a thickness. Since the plating layer of 8 to 20 μm was deposited, the electric resistance of the metallizing layer for sealing becomes high, and when the metal lid is seam welded to the metalizing layer for sealing via a brazing material, welding is performed. Since a large amount of current flows through the metal lid, it is possible to suppress the heat generation of the sealing metallization layer by reducing the welding current, and the brazing material between the sealing metallization layer and the metal lid. Can be welded well. In addition, a plating layer having a thickness of 8 to 20 μm composed of a nickel layer and a palladium layer, in which thermal stress applied to the sealing metallization layer and the insulating base during welding is applied to the sealing metallization layer, is better. As a result, it is possible to effectively prevent cracks due to thermal stress during welding on the metallization layer for sealing and the insulating substrate. Therefore, it is possible to provide an electronic component storage package that is excellent in the productivity of sealing work and has high airtight reliability.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of an electronic component storage package according to the present invention.
2 is a cross-sectional view showing a method of joining the insulating base 1 and the metal lid 2 of the electronic component storage package shown in FIG. 1 through a brazing material 8 by seam welding.
3 is an enlarged cross-sectional view of a main part of the electronic component storage package shown in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Insulation base | substrate 1a ... Mounting part 2 ... Metal lid 3 ... Electronic component 4 ... Metallized wiring conductor 6 ... For sealing Metallized layer 8 ... brazing material 9 ... nickel layer 10 ... palladium layer 11 ... plated layer

Claims (2)

An insulating base having a mounting portion on which an electronic component is mounted on the upper surface, a sealing metallization layer attached so as to surround the mounting portion, and a brazing material on the lower surface. In an electronic component storage package comprising a metal lid joined to a layer by seam welding via the brazing material,
The metallizing layer for sealing has a thickness of 4 to 8 μm, and is composed of a nickel layer and a palladium layer sequentially deposited on the surface, and a plating layer having a thickness of 8 to 20 μm is deposited. A package for storing electronic components. The electronic component storage package according to claim 1, wherein the palladium layer has a thickness of 3 μm or less.

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