JPS6295836A - Mounting device for semiconductor element - Google Patents

Abstract

PURPOSE:To prevent bubbles from being discharged along with a bonding agent to be discharged by the deaerating action of ultrasonic wave by a method wherein a means to give ultrasonic vibrations to a cylindrical container to house the bonding agent, which is a material to be discharged, is adopted. CONSTITUTION:One end of a cylindrical container 1 is provided with a discharge hole 2 with a small diameter and the other end is provided with a pressure transfer hole 4 for transferring pressure to press a bonding agent 3 to be injected with air pressure. At that time, the container is annexed with an ultrasonic vibration part 6 connected with an ultrasonic generator 5. Whereupon, bubbles being included in an epoxy silver paste rises to the upper part of the cylindrical part and disappear or cease to exist in the vicinity of the discharge hole 2. Accordingly, the inclusion of the bubbles in the bonding agent to be discharged is almost eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a mounting device used when mounting a semiconductor element on a lead frame using an adhesive.

[Technical background of the invention]

Conventionally, in the assembly process of semiconductor devices, a method has been commonly adopted in which after mounting on a lead frame, the electrodes of the semiconductor device and the leads of this lead frame are electrically connected using thin metal wires using thermocompression bonding. A method using a gold-silicon eutectic and a method using an adhesive such as silver paste have also been adopted.

As for the types of adhesives, adhesives such as epoxy silver paste, which contain a relatively large amount of solvent, and non-solvent types, which have a high viscosity, are known.

When applying such an adhesive to a so-called mounter, a syringe, which is a mounting device shown in FIG. 2, is used. This syringe (10) has an outer diameter of 13 mm
At one end of the cylindrical container (11) with an inner diameter of 0.8 mm
Install a hole (12) and inject adhesive (13) at the other end.
It has a structure in which a pressure transmission hole (14) is installed to pressurize.

As mentioned above, the adhesive to be injected is epoxy silver paste with a viscosity of 200 to 300c/p, or solvent-free adhesive with a viscosity of about 500c/p, but the pressure transmission hole of the syringe (14) For epoxy silver paste, an air pressure of about 2 kg/ci is applied for a certain period of time to discharge the epoxy silver paste, which is the material to be discharged.

This pressurizing time depends on the characteristics of the mounting device, but for this epoxy silver paste, it is about 1 m5ec/piece.

[Problems with background technology]

If air bubbles (14) are mixed in the adhesive injected into the syringe, a problem arises in that the amount of the adhesive to be dropped onto the bed portion of the lead frame becomes uneven. This is because, as mentioned above, air pressure is only applied to the adhesive for a certain period of time, and when these air bubbles pass through the discharge hole with a small diameter, they affect the amount of adhesive. Semiconductor devices that are assembled as they are are not only unpopular with society, but also have the disadvantage of lowering their reliability. [Object of the Invention] The present invention provides a novel semiconductor device mounting device that eliminates the above-mentioned difficulties.

[Summary of the Invention] In order to achieve the above object, the present invention employs means for applying ultrasonic vibration to a cylindrical container containing an adhesive, which is a material to be discharged, to prevent bubbles from being discharged together with the adhesive to be discharged. This is prevented by the degassing effect of ultrasonic waves, thereby improving the reliability of semiconductor devices.

[Embodiments of the invention]

The present invention will be explained in detail with reference to FIG.

One end of the cylindrical container (1) with an outer diameter of about 13) has an inner diameter of 0.8
A discharge hole (2) with a small diameter of mm is provided, and a pressure transmission hole (4) is provided at the other end to transmit pressure to press the adhesive (3) to be injected by air pressure.

As this adhesive, one having a viscosity of 200 to 300 c.p, such as epoxy silver paste, or a viscosity of 1500 c.p, such as a solvent-free adhesive, can be used. In addition, this cylindrical container is equipped with an ultrasonic vibrator (5) connected to an ultrasonic generator (5).
) is attached to the outer wall of the cylindrical body of the discharge hole (4) from a position approximately half the volume of the adhesive material. By installing this ultrasonic vibrating part, the air bubbles mixed in the epoxy silver paste will rise to the top of the cylindrical vessel and disappear, or they will no longer exist near the discharge hole (2).
Therefore, the mixing of air bubbles into the discharged adhesive is almost eliminated.

Adhesives that have a relatively large amount of solvent mixed in as mentioned above tend to have air bubbles, and solvent-free adhesives have a characteristic that it is difficult for air bubbles to escape. Most of the contamination has been eliminated.

〔Effect of the invention〕

In this way, the mounting device according to the present invention prevents air bubbles from being mixed in with the adhesive supplied to the bed portion of the lead frame, so the amount of adhesive discharged is constant, and the bond between the semiconductor element and the bed portion maintains a constant strength. becomes possible.

That is, it is possible to prevent deterioration in product quality caused by excess or deficiency in discharge amount, and to improve reliability.

This point is clear from the materials below.

As described above, the present invention has improved the defective rate by about one order of magnitude compared to the conventional example, and its effectiveness is clear. Therefore, not only the mounting operation can be automated extremely smoothly, but also high viscosity adhesives, which are difficult to remove air bubbles from, can be used.

[Brief explanation of drawings]

FIG. 1 is a sectional view schematically showing a mounting device according to the present invention, and FIG. 2 is a sectional view of a conventional device.

Claims (1)

[Claims] A discharge hole with a smaller diameter is provided at one end of the cylinder, and a pressure applying mechanism is arranged at the other end, and ultrasonic waves are applied to the cylinder from a position approximately half the volume of the material to be discharged to be injected to a position between the discharge holes. A mounting device for a semiconductor device, characterized in that a vibrating part can be mounted.