JPH02121352A - Sealing of hybrid ic - Google Patents

Abstract

PURPOSE:To make possible a hermetic sealing easily and at a prescribed position by a method wherein a plurality of places are subjected to virtual welding by a spot irradiation using a laser beam, then, a necessary marking is put on the places, and after a vacuum drying treatment is performed, the laser beam is irradiated on the whole peripheries of the places and the places are welded and sealed. CONSTITUTION:A necessary electronic component 2 is mounted and thereafter, a metal cap 4 which is ready-prepared in advance is arranged in such a way that its opening end edge parts 4a are made to come into contact opposedly to a welded ring 3. In this state, a load is desirably applied properly to the cap 4 and the parts, which come into contact opposedly to the ring 3, of the parts 4a of the cap 4 are subjected to spot irradiation with a laser beam at proper intervals to perform temporary weldings 6. After the temporary virtual welding and a temporary virtual fixing are conducted with the spot irradiation using the laser beam, a vacuum drying is performed for one hour or thereabouts at 100 deg.C, for example, and thereafter, the parts, which come into contact opposedly to the ring 3, of the parts 4a of the cap 4 are subjected to laser beam irradiation over their whole peripheries and the parts, which come into contact opposedly to the ring, of the parts 4a are welded and sealed on a whole. Thereby, a sealing of a necessary hybrid IC is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for sealing a hybrid IC, and particularly to an improvement in a method for sealing a weld ring and a metal cap by laser welding.

(Prior Art) Metal cap-sealed hybrid IC circuit elements and devices have been put into practical use for the purpose of downsizing and increasing the reliability of electronic components and circuits. For example, as shown in the longitudinal section in FIG.
An opening edge 4a of a metal cap 4 is brought into contact with a weld ring 3 formed on the predetermined surface so as to mount an electronic component 2 such as an element and surround the electronic component 2,
Hybrid IC devices or circuits formed by laser welding and sealing are known. In addition, in FIG. 2, 5 is a lead terminal connected to the sealed electronic component 2 or the circuit.

By the way, this kind of metal cap sealed hybrid I
The metal cap 4 in the C circuit or device is sealed in the following manner. That is, after mounting the electronic components 2 and subjecting them to vacuum drying at 100° C. for about one hour, the open edge of the metal cap 4 is placed in a weld ring 3 formed to surround the electronic components 2 mounted thereon. 4a facing each other and temporarily fixed with adhesive tape or the like, the contact portion between the weld ring 3 and the opening edge 4a of the metal cap 4 is successively irradiated with a laser beam over the entire circumference. It is welded and sealed. Further, after the welding and sealing, the metal cap is marked with necessary markings and the marks are dried and fixed.

(Problems to be Solved by the Invention) However, in the above sealing method, the following disadvantages are often observed. That is, even if an attempt is made to weld and seal the entire circumference by successively irradiating the laser beam with the entire circumference temporarily fixed with adhesive tape or the like, the weld ring 3, which is the welded part, and the opening of the metal cap 4 will be damaged. A gap may remain between the end edge 4a and airtight sealing is difficult. In other words, since there are generally warps and twists in the weld ring 3, metal cap 4, and its opening edge 4a, temporary fixation using the adhesive tape may cause positional deviation, making it impossible to achieve the desired sealing. In addition, the distortion generated in the metal cap 4 during the sealing process around the entire circumference will be concentrated at the final sealing part, which will easily deteriorate the impact resistance and reduce long-term reliability. There's a problem. Moreover, when temporary fixing methods such as the above-mentioned adhesive tape are used,
Removal of the adhesive tape after the required sealing work is complicated, and there are also disadvantages such as spoiling the appearance. In addition, moisture and dust may enter between the vacuum drying process and the end of sealing, leading to migration, and additional steps such as drying the markings are required, so the mounted IC elements may be affected by diffusion due to heat cycles. There is a disadvantage that the bonding strength between the electrode and the Au wire is reduced.

[Structure of the Invention (Means for Solving the Problems) The present invention has been made in response to the above-mentioned circumstances, and relates to laser welding sealing between the metal cap and the weld ring in the configuration of the hybrid IC. First, we temporarily weld multiple points by spot irradiation with a laser beam, then make the necessary markings if necessary, perform a vacuum drying process, and then irradiate the entire circumference with a laser beam to weld and seal. The main point is to stop

(Function) According to the method of the present invention, the opening edge of a metal cap for sealing and internalizing electronic components mounted on a predetermined ceramic substrate is placed in contact with a pre-formed weld ring, and then The laser beam is irradiated in spots at regular intervals, and multiple points are welded to temporarily fix the parts. Therefore, unlike the case of temporary fixing with adhesive tape or the like, positional displacement is suppressed, and the gap between the surfaces of the welded parts formed by the weld ring and the opening edge of the metal cap is also reduced. Therefore, not only can airtight sealing be easily performed at a predetermined position, but also the distortion that occurs in the metal cap during the subsequent welding process due to laser beam irradiation over the entire circumference can be avoided.
Since it is completely dispersed, impact resistance is also greatly improved.

Furthermore, after the above-mentioned temporary fixing (temporary fixing), a vacuum drying process is performed to seal the entire structure, which prevents the intrusion of moisture and dirt, and also eliminates the need for a separate drying process for markings. becomes.

(Example) Hereinafter, with reference to FIG. 1, an example according to the first invention will be described. First, a ceramic substrate 1 is prepared, on which a predetermined circuit pattern and a weld ring 3 are previously provided in a predetermined area on one main surface, and required lead terminals are attached. Electronic components, such as IC elements, chip capacitors, chip resistors, etc., are mounted and mounted on a predetermined area of the circuit pattern forming surface of the ceramic substrate 1. After the required electronic components are mounted in this manner, the metal cap 4 prepared in advance is placed with its mouth edge 4a facing the weld ring 3. In this state, if necessary, apply an appropriate load to the metal cap 4, and spot-irradiate the contact area between the opening edge 4a of the metal cap 4 and the weld ring 3 with a laser beam at an appropriate interval. temporary welding 6 is performed. The temporary welding 6 by spot irradiation with the laser beam is performed as follows. That is, in the case of a rectangular hybrid IC circuit or device as shown in plan in FIG. 1, a first corner part A1 a second corner part B1 a third corner part C5
Welding is performed first at diagonal positions, such as a portion of the fourth corner, and then between these corners, that is, on each side, in sequence.

After temporarily welding and fixing by spot irradiation with the laser beam, vacuum drying is performed at, for example, 100° C. for about an hour, and then the opening edge 4a of the metal cap 4 and the weld ring 3 are bonded together. The required sealing of the hybrid IC is achieved by irradiating the opposing portions with a laser beam over the entire circumference and welding and sealing the opposing portions as a whole.

Next, an embodiment according to the second invention will be described. The basic means and steps are the same as in the case of the first invention, and after arranging the opening edge 4a of the metal cap 4 and the weld ring 3 facing each other, the facing part is placed in the spot of the laser beam. Temporary welding and fixing (temporary welding) is performed by irradiation. After temporary welding and fixing by laser beam spot irradiation, required markings are made at predetermined positions on the four surfaces of the cap, and vacuum drying is performed at, for example, 120° C. for about 1 hour to seal the sealed object and the cap. Dry the marked marks at the same time. After that, a laser beam is irradiated all around the contact area between the opening edge 4a of the metal cap 4 and the weld ring 3, and the contact area is welded and sealed as a whole, thereby improving reliability. This enables high sealing. In other words, the mark is vacuum-dried while temporarily fixed, and the required dehumidification and dust removal are performed, and the mark is quickly dried and fixed. The contact portion with the ring 3 is easily and tightly sealed. Therefore, the sealing performance is improved, and more reliable sealing is achieved.

In addition, although the above example shows the case where the contact area between the opening edge 4a of the metal cap 4 and the weld ring 3, that is, the welded sealing area, is square, it is not limited to the square shape, but may be circular, oval, etc. It can also be applied in the case of Further, the order of spot welding by laser beam irradiation is not necessarily limited to the above example.

[Effects of the Invention] According to the method of the present invention, electronic components such as IC elements mounted and mounted on a ceramic substrate in advance can be easily and airtightly sealed with a metal cap. That is, according to the present invention, the weld ring and the opening edge of the metal cap are
When performing welding and sealing by laser beam irradiation, first spot welding is performed at multiple locations and fixed. Due to this spot welding, even if there is warpage or twisting in the weld ring, metal cap, or the opening edge thereof, there is a certain amount of play or relief, so that -
Welded from time to time.

As described above, the weld ring and the edge of the opening of the metal cap are irradiated with a laser beam in spots, and after being partially welded and fixed, a vacuum drying process is performed to dehumidify, remove dust, etc., and then completely The circumferences are welded and sealed by laser beam irradiation.

During this process of welding and sealing by laser beam irradiation over the entire circumference, the inside of the metal cap (sealed part) is maintained in a clean state, and there is a gap between the weld ring and the metal cap in advance. Due to the reduced state of contact, the required sealing takes place reliably and airtightly. Moreover, since the weld ring and metal cap are already dispersed and welded and fixed at multiple locations, the distortion that occurs in the metal cap during welding over the entire circumference is not concentrated but is dispersed throughout. exhibit a condition.

Therefore, it also maintains excellent thermal shock resistance, maintains and exhibits the required sealing function over a long period of time, and has a no-ibrid I.
This also greatly contributes to improving the reliability of the C device or circuit. Furthermore, even when the cap is marked with the required markings, this is done simultaneously during the vacuum drying process, which reduces thermal cycles and prevents deterioration in bonding strength, thereby improving the reliability of electrical connections.

[Brief explanation of drawings]

'W41 is an explanatory diagram for explaining an embodiment of the method of the present invention, and is a top view showing a state in which the laser beam is spot irradiated and welded and fixed at multiple locations, and Figure 2 is a diagram showing a metal cap sealed hybrid IC. FIG. 3 is a vertical cross-sectional view showing a configuration example. 1...Ceramic substrate 3...Weld ring 4...Metal cap 4a...Opening edge of metal cap 6...Temporary welding (-temporary welding) part Applicant: Toshiba Corporation

Claims (2)

[Claims] (1) IC mounted on a predetermined surface of a ceramic wiring board
A hybrid IC in which an opening edge of a metal cap is brought into contact with a weld ring formed on the predetermined surface so as to surround an electronic component including an element, and is sealed by laser welding.
In the sealing method of the hybrid IC, the weld ring and the opening edge of the metal cap are temporarily welded at a plurality of locations, vacuum dried, and then laser welded over the entire circumference to seal the hybrid IC. Sealing method. (2) IC mounted on a predetermined surface of a ceramic wiring board
A hybrid IC in which an opening edge of a metal cap is brought into contact with a weld ring formed on the predetermined surface so as to surround an electronic component including an element, and is sealed by laser welding.
In the sealing method, the weld ring and the opening edge of the metal cap are fixed and temporarily welded at multiple locations, and then the required markings are made, vacuum drying is performed, and the entire circumference is laser welded to seal. A method for sealing a hybrid IC, characterized by: