JP2003318299A - Package for containing electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable package for containing an electronic component in which airtight sealing can be carried out efficiently with a lower welding current level and cracking does not take place in the insulating basic body. <P>SOLUTION: The package for containing an electronic component comprises the insulating basic body 1 having a part 1a for mounting an electronic component 3 on the upper surface thereof and a sealing metallization layer 6 applied to surround the mounting part 1a, and a metal cover 2 having a lower surface applied with a solder material 8 and being bonded to the sealing metallization layer 6 through the solder material 8 by seam welding wherein the sealing metallization layer 6 has a thickness of 4-8 μm and a nickel plating layer having a thickness of 8-20 μm is applied to the surface thereof. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component such as a piezoelectric vibrator or a semiconductor element which is hermetically sealed in a package composed of an insulating base such as ceramics and a metal lid. The present invention relates to an electronic component storage package that is to be stored. 2. Description of the Related Art Electronic parts such as piezoelectric vibrators and semiconductor elements are used by being housed in an electronic part housing package for hermetically housing these electronic parts. In such an electronic component storage package for storing electronic components in an airtight manner, the most reliable one is made of ceramics such as an aluminum oxide sintered body, and the electronic component is mounted on the upper surface. An insulating substrate having a plurality of metallized wiring conductors having electrodes and electronic components electrically connected to the surface and the inside thereof, and a frame-like sealing metallization layer surrounding the mounting part and the mounting part;
A metal frame for sealing made of iron-nickel alloy or iron-nickel-cobalt alloy brazed so as to surround the mounting portion on the metallization layer for sealing of the insulating substrate, and a seam on the metal frame This type is composed of an iron-nickel alloy or a metal lid made of iron-nickel-cobalt alloy that is directly joined by welding. In the case of this type of electronic component storage package, an insulating substrate After mounting the electronic component on the mounting part and electrically connecting the electrode of the electronic component and the metallized wiring conductor via solder bumps, bonding wires, etc., the metal frame for sealing brazed to the insulating substrate A metal lid is placed, and a pair of roller electrodes of a seam welding machine are rolled while contacting the outer peripheral edge of the metal lid, and a large current for welding is provided between the roller electrodes. The metal frame and the metal cover member directly flow,
By performing seam welding, electronic components are housed in an airtight manner to form an electronic device as a product. 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. In order to solve the above-mentioned problems, a mounting portion for mounting an electronic component on the upper surface and a frame-shaped sealing metallization layer surrounding the mounting portion are provided. The insulating base made of ceramic having a plurality of metallized wiring conductors to which the electrodes are electrically connected, and a metal lid with a brazing material such as a silver-copper eutectic alloy applied to the lower surface, An electronic component is mounted on the mounting portion and each electrode of the electronic component is electrically connected to the metallized wiring conductor, and then seam welded to the sealing metallized layer through a brazing material having a metal lid attached to the lower surface thereof. Thus, an electronic component storage package has been proposed in which an insulating base and a metal lid are joined and an electronic component is hermetically sealed inside. An electronic component storage package in which an electronic component is hermetically accommodated by joining a metal lid to the sealing metallized layer by seam welding via a brazing material such as silver brazing, Since the metallization layer for sealing 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 accordingly. And inexpensive. [0007] It should be noted that the conventional metal part housing 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. In the package, the metallizing layer for sealing has a thickness of 10 μm or more, preferably 20 μm or more, and the surface has a thickness of 5 μm or more,
Preferably, a nickel plating layer having a thickness of 8 μm or more was applied. This is the thickness of the metallization layer for sealing 10μ
When the metal lid is seam welded to the metallization layer for sealing via the brazing material by depositing a nickel plating layer having a thickness of 5 μm or more on the surface thereof, Based on the idea that thermal shock caused by welding current applied to the insulating substrate is absorbed and relaxed by the thick metallizing layer for sealing and nickel plating layer to prevent cracks in the metallizing layer for sealing and insulating substrate. Is. However, as described above, the thickness of the metallization layer for sealing the insulating substrate is 10 μm.
According to the electronic component storage package in which a nickel plating layer having a thickness of 5 μm or more is applied thereon, the sealing metallization layer has a large thickness, so that the electrical resistance of the sealing metallization layer is low. Therefore, when a metal lid having a lower surface coated with a brazing material is joined to a sealing metallization layer of an insulating substrate by seam welding via a brazing material, the current for welding is sealed with low electrical resistance. A large amount of current flows through the metallization layer, and the current flowing through the metal lid is reduced. Therefore, in order to melt the brazing material applied to the metal lid satisfactorily with the welding current, an extremely large welding current must be applied, and a lot of extra power is consumed, so that the sealing productivity is high. In addition to being bad, the thermal stress due to such welding current also increases, so if the insulating substrate is thin, cracks occur in the metallization layer for sealing and the insulating substrate due to the stress remaining between the insulating substrate and the lid after welding. It had the problem that it was easy to end up. As a result of various studies in view of the above problems, the present inventor has made an electronic structure in which the metal lid is joined to the sealing metallization layer of the insulating base by seam welding through the brazing material as described above. In the component storage package, the metal lid layer has a high electrical resistance, and a large amount of welding current is passed through the metal lid to effectively heat the metal lid, and the hermetically sealed with a lower welding current. In addition to being able to be performed, by applying a nickel plating layer having a thickness equal to or greater than the thickness 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. At the same time, the thermal stress generated during welding is effectively relieved by the thick nickel plating layer, so cracks are unlikely to occur in the metallization layer for sealing and the insulating substrate after welding. It was discovered the door. The present invention has been devised based on such knowledge, and its purpose is lower when a metal lid is joined to a metallization layer for sealing an insulating substrate by seam welding via a brazing material. An object of the present invention is to provide a highly reliable electronic component storage package that can be hermetically sealed with a welding current and that does not cause cracks in a sealing metallized layer or an insulating substrate. The electronic component storage package of the present invention comprises a mounting portion on which an electronic component is mounted on an upper surface, and a sealing metallization layer deposited so as to surround the mounting portion. In an electronic component storage package, comprising: an insulating base having a brazing material on the lower surface; and a metal lid bonded to the sealing metallization layer via the brazing material by seam welding. The sealing metallization layer has a thickness of 4 to 8 μm, and a nickel plating layer having a thickness of 8 to 20 μm is deposited on the surface thereof. According to the electronic component storage package of the present invention, the sealing metallization layer has a thin thickness of 4 to 8 μm, and a nickel plating layer having a thickness of 8 to 20 μm is deposited thereon. Therefore, the electric resistance of the metallizing layer for sealing becomes high, and when the metal lid is seam welded to the metallizing layer for sealing via the brazing material, a large amount of welding current flows to the metal lid. So, that much,
The welding metallization layer can be prevented from generating a large amount of heat with a small welding current, and the sealing metallization layer and the metal lid can be favorably welded via the brazing material. Further, the thermal stress applied to the sealing metallization layer and the insulating base during welding can be satisfactorily absorbed by the nickel plating layer having a thickness of 8 to 20 μm applied to the sealing metallization layer. As a result, 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. DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an electronic component storage package according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an embodiment of an electronic component storage package according to the present invention. In FIG. 1, 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. The insulating substrate 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. The electronic component 3 is accommodated in the center of the upper surface thereof. It has a recess A to do. 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. 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 powders such as aluminum oxide, silicon oxide, magnesium oxide and calcium oxide. Then, it is made into a mud shape, and this is made into a ceramic green sheet by adopting the conventionally known doctor blade method and calendar roll method, and then,
The ceramic green sheet is manufactured by performing an appropriate punching process, stacking a plurality of sheets, and firing at a high temperature. Further, a metallized wiring layer 4 made of a metal powder sintered body such as tungsten or molybdenum derived from the upper surface of the mounting portion 1a to the lower surface of the insulating substrate 1 is deposited on the insulating substrate 1. The metallized wiring layer 4 functions as a conductive path for electrically leading each electrode of the electronic component 3 to the outside. Normally, the exposed surface is nickel-plated with a thickness of about 1 to 20 μm. And a gold plating layer having a thickness of about 0.1 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. If the metallized wiring layer 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 used as a ceramic green for the insulating substrate 1. The sheet is printed and applied in a predetermined pattern by a conventionally 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 insulating substrate 1. Is done. Further, the outer peripheral portion of the upper surface of the insulating substrate 1 is made of a sintered metal powder such as tungsten or molybdenum,
A frame-shaped sealing metallization layer 6 having a width of about 0.4 mm and a thickness of 4 to 8 μm is formed so as to surround the mounting portion 1 a. This sealing metallization layer 6 is composed of an insulating substrate 1
It functions as a base metal for bonding the metal lid 2 to the surface, and a nickel plating layer having a thickness of about 8 to 20 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are applied to the exposed surface. . And the metal cover body 2 is joined on it by the seam welding through the brazing material 8. FIG. If the sealing metallization layer 6 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 used for the insulating substrate 1. A conventionally known screen printing method is applied to the ceramic green sheet in advance so as to be printed and applied in a predetermined thickness and pattern, and this is fired together with the ceramic green sheet for the insulating base 1, thereby mounting the mounting portion 1a on the upper surface of the insulating base 1. It is deposited so as to surround it. 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. A brazing filler metal 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. Is joined to the metallization layer 6 for soldering via the brazing material 8, thereby the insulating substrate 1
The electronic component 3 is hermetically sealed between the two. Such a metal lid 2 is obtained 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 thereof and rolling it. The composite metal plate having a large area in which a brazing material is pressure-bonded to the lower surface of the iron-nickel-cobalt alloy plate is obtained, and the composite metal plate is punched into a predetermined shape by a punching die. In the electronic component storage package of the present invention, the thickness of the sealing metallization layer 6 is 4 to 8 μm.
The thickness of the nickel plating layer deposited on the surface of the sealing metallization layer 6 is 8-2.
This is important because it is 0 μm. The sealing metallization layer 6 is formed with a thickness of 4 to 8 μm, and a nickel plating layer having a thickness of 8 to 20 μm is deposited thereon, so that the nickel plating layer is deposited thereon. As a result, when the metal lid 2 is welded to the sealing metallization layer 6 through the brazing material 8 by seam welding, a large current is applied to the metal lid 2 side. Therefore, 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 8 deposited on the metal lid 2 can be melted well by the welding current and sealed. The metallized layer 6 and the metal lid 2 can be bonded well. The sealing metallization layer 6 has a thickness of 4 μm.
If it is less than m, it tends to be difficult to firmly attach the sealing metallization layer 6 to the insulating substrate 1.
When the thickness exceeds μm, the electrical resistance of the metallizing layer 6 for sealing becomes low, and the metal lid 2 is welded to the metallizing layer 6 for sealing by seam welding through the brazing material 8. The current flowing to the side 2 is reduced, and it is difficult to melt the brazing material 8 deposited on the metal lid 2 satisfactorily with a small welding current. Therefore, the thickness of the metallizing layer 6 for sealing is specified in the range of 4 to 8 μm. Further, 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 gradually thinned to the middle of the rounded portion. If it is made to extend, it can prevent effectively that the metallizing layer 6 for sealing peels from the insulating base | substrate 1. FIG. 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. The metal paste for forming the metallizing layer 6 for sealing is a metallizing layer for sealing which is as thin as 4 to 8 μm when the average particle size of the metal powder contained therein is 1 μm or less. 6 can be densely and firmly attached to the upper surface of the insulating substrate 1. 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. According to the electronic component storage package of the present invention, since the nickel plating layer deposited on the surface of the sealing metallization layer 6 has a thickness of 8 to 20 μm,
When the metal lid 2 is welded to the sealing metallization layer 6 via the brazing material 8 by seam welding, the sealing metallization layer 6
The thermal stress applied to the insulating substrate 1 can be satisfactorily absorbed and relaxed by the nickel plating layer deposited on the sealing metallization layer 6, and as a result, the metal lid 2 is attached to the sealing metallization layer 6. It is possible to effectively prevent the occurrence of cracks in the sealing metallized layer 6 and the insulating base 1 when welding by seam welding through the brazing material 8 and after welding. When the nickel plating layer deposited on the sealing metallization layer 6 is less than 8 μm, the metal lid 2 is welded to the sealing metallization layer 6 via the brazing material 8 by seam welding. In addition, 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. On the other hand, if the thickness exceeds 20 μm, the nickel plating layer having such a large thickness There is a tendency that cracks and peeling are likely to occur in the sealing metallized layer 6 due to the stress generated when the film is applied. Therefore,
The thickness of the nickel plating layer deposited on the sealing metallization layer 6 is specified in the range of 8 to 20 μm. Thus, according to the electronic component storage package of the present invention, the electronic component 3 is mounted on the mounting portion 1a of the insulating base 1, and the metal lid 2 is mounted on the metallizing layer 6 for sealing.
By joining the brazing material through the brazing material 8 by seam welding, a highly reliable electronic component storage package that does not cause disconnection in the metallized wiring conductor 4 or cracks in the insulating base 1 is provided. be able to. It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. [Experimental Example] The width is 2.20 mm at the center of the upper surface and the length is 4.
On the outer periphery of the upper surface of an insulating substrate made of a square box-shaped alumina ceramic having a rectangular recess of 00 mm and a depth of 0.30 mm, a width of 3.20 mm, a length of 5.00 mm, and a thickness of 0.55 mm 1 to 11 μm of a rectangular frame-shaped sealing metallization layer made of tungsten metallization having a width of 0.50 mm and surrounding the recess and extending to the outer peripheral edge
In addition, a nickel plating layer having a thickness of 5 to 23 μm and a gold plating layer having a thickness of 0.3 μm were deposited on the metallizing layer for sealing, and 10 samples for each experiment were applied. Obtained. The width is 2.90m
m, an iron-nickel-cobalt alloy having a length of 4.70 mm and a thickness of 0.10 mm.
A metal lid with a brazing material made of a silver-copper eutectic alloy of μm was prepared. Next, a metal lid is placed on the metallization layer for sealing of each sample with the brazing material facing down, and a pair of roller electrodes of the seam welding apparatus is placed between the outer peripheral edges of the metal lid facing each other from above. A welding current of 230 A was applied between the roller electrodes while contacted while applying a load of 200 g and moved at a speed of 10 mm / sec to seam weld the metallized layer for sealing and the metal frame through a brazing material. . Next, after each sample to which the metal lid was welded was allowed to stand at room temperature for one month, each sample was observed with a microscope to check for the presence of cracks in the sealing metallized layer and the insulating substrate. The results are shown in Table 1. Note that samples Nos. 1, 2, 6, 7, 11, 12, and 13 in Table 1 are samples for comparison outside the scope of the present invention. [Table 1] As can be seen from Table 1, although Samples 1, 2, 6, 7, and 12 for comparison show cracks after being left for one month, Samples 3, 4, 5, 8, 9, 10
Then, no crack was generated. Further, although no cracks were observed in the samples 11 and 13 for comparison, the brazing material did not melt well at the welding current of 230 A, and the brazing material was insufficiently melted. As described above, according to the electronic component storage package of the present invention, the thickness of the sealing metallized layer is as thin as 4 to 8 μm, and the thickness thereof is further increased. Since the 8-20 μm nickel plating layer was deposited, the electrical 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. Further, the thermal stress applied to the sealing metallization layer and the insulating base during welding can be satisfactorily absorbed by the nickel plating layer having a thickness of 8 to 20 μm applied to the sealing metallization layer. As a result, 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. 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. [Explanation of Symbols] 1... Insulating substrate 1 a... Mount 2. Metal lid 3. Electronic component 4. ..Metalizing layer 8 for sealing

Claims (1)

What is claimed is: 1. An insulating substrate having a mounting portion on which an electronic component is mounted on an upper surface, a sealing metallization layer deposited so as to surround the mounting portion, and a brazing material on the lower surface. In the electronic component storage package which is attached and is composed of a metal lid which is joined to the sealing metallized layer by seam welding via the brazing material, the sealing metallized layer has a thickness of 4 A package for storing electronic parts, characterized in that a nickel plating layer having a thickness of 8 to 20 μm is deposited on the surface thereof.