JPS5896754A - Airtightly sealed package - Google Patents

Abstract

PURPOSE:To mount IC chips in high density by a method wherein the outside circumferential shape of a welding ring to be provided on a wiring substrate having a special external form of circle, ellipse, etc., is formed in a polygon having sides facing each other in parallel and being other than a square or a rectangle. CONSTITUTION:The external form of an Al2O3 ceramic wiring substrate 6-1 is a circle, and the welding ring 6-4 for airtightly sealing having the equal coefficient of thermal expansion is soldered with silver solder 6-5 to the circumferential part. When the external form of the welding ring 6-4 is formed in a regular octagon, for example, the area possible to mount can be secured effectively, and the IC chips can be mounted in high density. The substrate having the equal coefficient of thermal expansion is positioned to the sealing ring, and the whole is sealed airtightly to complete.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical field to which the invention pertains The present invention is directed to mounting at least one chip component such as an IC chip on a wiring board made of alumina ceramic or the like, and attaching a base such as a cap to the wiring board made of alumina ceramic or the like. This relates to the structure of a hermetically sealed package that is attached to the top of the package and hermetically seals the entire package.0 Conventional technology and its problemsIn recent years, the demand for smaller, lighter, and more reliable electronic devices has increased significantly. A so-called multi-chip packaging technology is being developed in which at least one electronic functional element such as an IC is mounted in the form of a chip on a high-density multilayer wiring board made of alumina ceramic or the like, and the whole is hermetically sealed. Conventional methods for hermetically sealing such packages include molding with epoxy or plastic, but these are not considered to be very desirable from a reliability standpoint; Methods such as soldering or using low-melting glass are being developed, but if even higher reliability is required, hermetically sealed packages using welding are being developed. In this case, conventionally, as shown in FIG.
A square or rectangular ring-shaped conductor pattern 1-3 is formed around the conductor pattern 1-2 on which a chip component such as an IC chip on the top 1 is mounted, and the square or rectangular ring-shaped conductor pattern 1 As shown in FIG. 2, the periphery of the wiring board 1-1 made of copper or Fe-Ni 42 alloy, which has approximately the same coefficient of thermal expansion as the wiring board 1-1 made of alumina ceramic, etc. It has a width smaller than the conductor pattern width of the IE square or rectangular ring-shaped conductor pattern l-3, and has a width of 0.
Weld link 2-4, which is a square or rectangular (b) ring-shaped metal base for welding with a thickness ranging from 1 to a number.
The weld ring 3-4 (2-4) is attached to the wiring board 3-4 made of alumina ceramic or the like by, for example, forming the weld ring 3-4 (2-4) with an etching or cutting die and fixing it with an adhesive 3-5 such as Ag wax. It was formed on 1. FIG. 3 shows a sectional view thereof. 4(a) or (
b) A cap having a square or rectangular external shape made of Kovar or Fe-Ni42 alloy, etc., which has a coefficient of thermal expansion approximately equal to that of the well link 3-4 and the wiring board 3-1 made of alumina ceramic, etc., having a cross-sectional shape such as b). By aligning the periphery of the base 4-6-2 or 4-6-b such as a cap with the periphery of the weld link 5-4 as shown in FIG. Welding is performed by pressing the opposing electrodes 5-7 against opposing peripheries of the iE square or rectangle and moving the stage of the welding device on which the wiring board 5-1 is mounted straight ahead.
By doing so, the entire package was hermetically sealed.

However, with this method, there is no problem if the outer shape of the package is square or rectangular, but if the base body such as the casing on which the package is mounted is square or rectangular, there is no problem. The inner periphery of the base body must be formed into a circular or elliptical shape, and at least one or more chip components 5-8 such as ICs must be mounted thereon. When the link 2-4 is formed, for example, if the outer periphery of the wiring board 1-1 is circular, the weld ring becomes a square-shaped weld ring inscribed therein, so it is difficult to mount the chip component 5-8 such as an IC. A considerable area of dead space exists on the wiring board 1-1, which in turn impedes high-density mounting.

Further, in the case of a wiring board having a circular external shape, it is possible to form the weld ring into a circular shape having a slightly smaller outer periphery than the outer periphery of the wiring board, but in this case, the wiring board 5-1 of the welding device is The stage, which had one additional support, had to be modified so that it could rotate, which required a great deal of cost and effort. In addition, in the case of a circular shape, it is possible to deal with it by modifying the stage that supports and fixes the wiring board of the welding device so that it can rotate, but in the case of a shape that is oval in various shapes, there is nothing that can be done. Purpose of the Invention The present invention has been made in consideration of these circumstances,
The purpose is to mount at least one chip component such as an IC on a wiring board made of alumina ceramic or other material that has a special external shape other than a square or rectangle, such as a circular or oval shape. The object of the present invention is to provide an airtight package that can efficiently secure a mounting area, be densely mounted, and hermetically seal the entire package.

Embodiment of the Invention An embodiment of the present invention will be described below with reference to the drawings. Figure 6 ((a) top view, (b) M UfJ diagram) is
This is an example in which the wiring board 6-1 made of alumina ceramic or the like has a circular outer shape, and 6-4 shows the outer shape structure of the weld ring according to the present invention. In this case, the shape is a regular octagon, but by forming the opposing electrode 5-
It is possible to efficiently mount a large number of chip components on the wiring board 6-1 having a circular external shape and hermetically seal the whole without modifying the welding device having a stage that moves in a straight line. It has become possible to provide a hermetically sealed package. 6-5 shows an adhesive such as silver solder for supporting and fixing the weld ring 6-4 on top of the wiring board 6-. Figure 7 shows another embodiment of the present invention, in which 7-1 shows a wiring board with a rectangular outer shape, and 7-9 shows how to attach it to a base such as a casing. The through holes 7-9 are present in the four corners of the rectangular wiring board 7-1. 7-4 shows a weld ring outer shape structure according to the present invention in which opposing outer peripheries have parallel quadrangular shapes. 7-5 indicates an adhesive such as silver solder for supporting and fixing the weld link 7-4 on the wiring board 7-1.

Effects of the Invention By adopting the present invention, a welding device having a stage for supporting and fixing a wiring board that is oppositely polarized and moving in a straight line can be efficiently welded to a wiring board that has a special outer shape other than a square or rectangle without any modification. It has become possible to provide a hermetically sealed package that can mount a large number of chip components at a high density and hermetically seal the entire package with high reliability.

[Brief explanation of the drawing]

1 to 5 are diagrams explaining a conventional example, FIG. 6 is a diagram showing one embodiment of the present invention, and FIG. 7 is a diagram showing another embodiment according to the present invention. 1-1.1-1.5-1.6-1.7-1... Wiring board of alumina ceramic etc., 2-4.3-4.5-4.6-4.7-4... Weld ring. 4-6-a, 4-6-b, 5-6・Substrate such as cap, 3-5, 5-5, 6-5, 7-5・
・Adhesive layer between weld link such as silver solder and wiring board, 5-8 ・Chip components such as IC, 5-7. Opposing electrodes of welding equipment, 1-2. Conductive pattern for mounting chip components. , 1-3 ・Conductive butter for mounting weld ring 7,■-9...Package input/output terminals are installed with conductive pattern Patent attorney Nori Chika
Kensuke (and 1 other person) c12cv″ll ← Law 213- Measurement method

Claims (1)

[Claims] (1) At least one chip component, which is an electronic functional element, is mounted on the wiring board. A weld ring for airtight sealing having a coefficient of thermal expansion approximately equal to that of the wiring board is attached to the peripheral portion of the wiring board using an adhesive, and a weld ring having a coefficient of thermal expansion approximately equal to that of the wiring board and the weld ring is mounted on the weld ring. In a hermetically sealed package in which the periphery of the base is aligned with the periphery of the weld ring and the whole is hermetically sealed, the shape of the outer periphery of the weld ring is opposite to each other in a shape other than square or rectangular. A hermetically sealed package characterized by a polygonal shape with parallel outer peripheries.