JPH0778896A - Hermetic sealing of semiconductor module - Google Patents

Abstract

PURPOSE:To improve the wettability of a eutectic alloy, to ensure an airtightness in a package and at the same time, to contrive a miniaturization of the package and moreover, to make it possible to seal a semiconductor module in a short time by a method wherein when the package is made to bond on a cap, the package or the cap is made to scribe. CONSTITUTION:A cap 3 is transferred in a jig 5 placed on a heater 7, then, an annularly formed Au-Sn eutectic alloy 4 is transferred on the cap 3 and moreover, a package 2 with a semiconductor module 1 built in the interior thereof is transferred on the alloy 4. With the package 2 pressed by a collet 6, the heater 7 is energized vibrations are given by an ultrasonic vibration device 8 mounted to the collet 6 and the package 2 or the cap 3 is made to scribe. Moreover, a gap is held between a recess formed in the jig 5 and the package 2 for giving the scribing. Thereby, an impurity generated by the incompleteness of the junction surface between the package and the cap is removed and the wettability of the package 4 can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for hermetically sealing a semiconductor module including an integrated circuit (IC), a field effect transistor (FET) and the like.

[0002]

2. Description of the Related Art As electronic devices are required to have a large scale and a high speed, as a countermeasure, a large number of small parts are mounted on a substrate and a circuit having a high speed is shielded for each function. There is. FIG. 2 is a side view showing a conventional method for hermetically sealing the above semiconductor module. A eutectic alloy 4 such as Au-Sn or Au-Si is formed on the joint surface between the metal or ceramic package 2 containing the semiconductor module 1 and its cap 3.
Is placed on the jig 5 and a weight 9 is placed on the package 2 to apply pressure. This is put in a furnace to melt the eutectic alloy 4, or the jig 5 is heated by applying a current to a heater (not shown) to bond the package 2 and the cap 3 to each other, and the hermetic sealing method is performed.

[0003]

According to such a conventional method, when the joint surface between the package 2 and the cap 3 is not flat, the eutectic alloy 4 becomes less compatible with the joint surface and partially There was a problem in that an oxide film was formed on the surface and it adhered, but the airtightness could not be secured. In addition, we considered thinning the wall thickness of the package in response to the demand for miniaturization of the package, but the airtightness is likely to be incomplete, and if the heating time is increased to secure the airtightness, the semiconductor module deteriorates. There was a limit. Therefore, an object of the present invention is to provide a method for hermetically sealing a semiconductor module that solves the above problems.

[0004]

A method for hermetically sealing a semiconductor module according to the present invention is such that a eutectic alloy is inserted into a joint surface between a package containing a semiconductor module and a cap, and the eutectic alloy It is characterized in that the package or the cap is scrubbed at the time of bonding by heating to a temperature higher than the melting point. In the above method, it is preferable to perform scrubbing with an ultrasonic vibration device and to perform heating at 300 ° C. or lower and within 10 seconds.

[0005]

According to the above method, the method of hermetically sealing a semiconductor module according to the present invention scrubs the package or the cap when adhering the package and the cap, so that the eutectic alloy is oxidized due to the imperfections of the joint surface. Since the film (SnO ₂ etc.) and other impurities are removed and the wettability of the eutectic alloy is improved, airtightness can be secured. Further, since the airtightness can be ensured even if the wall thickness of the package is reduced, the package can be downsized.
Furthermore, since sealing can be performed in a short time, heat deterioration of the semiconductor module can be suppressed and reliability is improved.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description. FIG. 1 is a side view showing the configuration of the present embodiment, in which a cap is conveyed into a jig 5 installed on a heater 7, and then the cap 3
A eutectic alloy 4 made of Au—Sn formed in a ring shape on the top of the eutectic alloy 4, and a package 2 having the semiconductor module 1 therein is conveyed on the eutectic alloy 4. These parts are adsorbed and carried by a collet 6 having a through hole 6-1 in the center.

Next, the collet 6 was able to pressurize the package 2 and at the same time heat the heater 7 to 300 ° C., and vibrate it by the ultrasonic vibrating device 8 attached to the collet 6 to bond it in 10 seconds. Conventionally, when the sealing is incomplete, the semiconductor module may be deteriorated due to repeated bonding and heating for a long time, but the method of the present invention enables sealing in a short time, thus improving module reliability. did. The scrub can also give a vibration by rotating the shaft of a disc mounted eccentrically with a small motor. The recess of the jig 5 and the package 2 to give the scrub
There should be a gap between them. When the joint portion of the package sealed by the above method was inspected with a microscope and a soft X-ray transmission apparatus, it was confirmed that there were no bubbles and that the package was completely sealed.

[0008]

As described above, in the method for hermetically sealing a semiconductor module according to the present invention, when the package and the cap are bonded together, the package or the cap is scrubbed, so that the eutectic alloy produced by the imperfections of the joint surface is formed. Since the oxide film (SnO ₂ etc.) and other impurities are removed and the wettability of the eutectic alloy is improved, airtightness can be secured. Further, since the airtightness can be ensured even if the wall thickness of the package is reduced, the package can be downsized. Furthermore, since sealing can be performed in a short time, heat deterioration of the semiconductor module can be suppressed and reliability is improved.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration of an embodiment according to the present invention.

FIG. 2 is a side view showing a conventional configuration.

[Explanation of symbols]

 1: Semiconductor Module 2: Package 3: Cap 4: Eutectic Alloy 5: Jig 6: Collet 6-1: Through Hole 7: Heater 8: Ultrasonic Vibration Device 9: Weight

Claims (3)

[Claims] 1. When a eutectic alloy is inserted in a joint surface between a package containing a semiconductor module and a cap and the pressure is applied to the eutectic alloy to heat it to a temperature equal to or higher than the melting point of the eutectic alloy for bonding, the package or the cap is attached. A method for hermetically sealing a semiconductor module, which comprises scrubbing. 2. The method for hermetically sealing a semiconductor module according to claim 1, wherein scrubbing is performed by an ultrasonic vibration device. 3. The method for hermetically sealing a semiconductor module according to claim 1, wherein the heating condition is 300 ° C. or lower and 10 seconds or less.