JPH03214643A - Vacuum suction jig - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a jig for manufacturing semiconductor devices, and is particularly effective when applied to a vacuum suction jig for attaching a semiconductor element to a support substrate using a conductive adhesive or the like. It is related to technology.

[Conventional technology]

Generally, when assembling a semiconductor device, after a semiconductor element is vacuum-adsorbed and held using a Guibonda vacuum suction jig (hereinafter referred to as a collet), solder is applied to a support substrate such as a tab formed on a lead frame, and Au-Si eutectic, etc. It can be attached using Ag paste or the like.

Among semiconductor devices, power transistors and power I
For relatively high-output products such as C and (・), it absorbs the stress caused by the difference in thermal expansion coefficient between the support substrate and the Pellenoto, which is caused by lower prices and temperature changes in the semiconductor element (hereinafter referred to as Pellenoto). For this purpose, solder, for example, is often used as a conductive adhesive.Such a recess has a structure in which a concave portion is formed on the side that comes into contact with the pellet, and the contact is made around the periphery of the pellet.

Documents showing such collets include "Integrated Circuit Technology" by Seiichi Denda, Published by Kogyo Kenkyukai, 1968, pp. 143-144, and "Industrial Technology Library 24, Bonding Technology" by Juichi Asaka, published by Nikkan Kogyo Shimbun. Showa 45
There are 76 negatives from the annual 75 self.

[Problem to be solved by the invention]

In a normal semiconductor device, since the amount of solder is small, 1/t as described above may be used, but when the present inventor attempts to use a high-output type semiconductor device with a conventional structure, it is difficult to use solder. The thickness of the solder is as thin as several microns, so when the number of switching increases in high-output devices, stress is generated that cannot be absorbed by the thickness of conventional solder, which can lead to defects such as berent cracks. Ta.

The inventors of the present invention have discovered that defects such as cracks in high-output semiconductor devices can be prevented by eliminating the above-mentioned problems and making the thickness between the supporting substrate and the pellet 40 μm or more.

However, such semiconductor devices require a larger amount of solder than conventional ones, so in order to form semiconductor devices with a thick solder layer on a lead frame made of copper or other materials,
A large amount of solder formed into a cube is placed on the lead frame,
When the bellet 1, which is held by a collector, is pressed against a tab that serves as a support substrate so as to sandwich the solder, the solder is squeezed out from the center of each of the four sides of the bellet, and the solder is removed due to surface tension. It was found that there was a problem in that the solder rose almost vertically, and as a result, the solder adhered to the collet, making it necessary to remove the solder from the adhered collet, making it unsuitable for mass production.

In addition, if the collet becomes contaminated with solder, it becomes impossible to completely remove the solder, and residual solder adheres to the collet using the collet, causing a short circuit on the collet (Problem 5). There was also.

Furthermore, in order to prevent such swelling, the lead frame is plated with solder etc. in advance.
There are methods to improve wettability with solder (1. To prevent solder from swelling, but plating makes semiconductor devices expensive. Also, when plating solder, etc., use a conductive adhesive. Considering the case where silver paste or the like is used, this cannot be said to be an optimal solution.

SUMMARY OF THE INVENTION An object of the present invention is to provide a collet suitable for mass production of semiconductor devices that has a sufficiently thick solder layer to prevent the occurrence of defects as described above.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

That is, in a collet that vacuum-chucks a rectangular pellet, the pellet and the collet 4 facing the pellet are
This is a collet with grooves provided on the outside of the central part of the sides so as to make contact near the four corners of the pellet.

[Effect]

According to the collet described above, by pressing the pellet against the support substrate, the adhesive protruding from the center of the four sides of the pellet does not adhere to the jig, so the collet is suitable for mass production without staining the pellet. Obtainable.

〔Example〕

Figure 1 is a side view of the vacuum jig of the present invention, Figure 2 is its front view, Figure 3 is its XX sectional view, and Figures 4 and 5 are shown in Figures 1 to 3. FIG. 3 is a side cross-sectional view for explaining a case in which the collet is manufactured using the same collet. FIG. 6 is a perspective view showing the case where a pellet is attracted by the collet shown in FIGS. 1 to 3, and FIGS. 7 and 8 are characteristics of a semiconductor device manufactured using the collet of the present invention. FIG.

The explanation will be given below with reference to the drawings.

In this embodiment, the collets of the present invention as shown in FIGS. 1 to 3 are used.

The recess 2 of the collet 1 is provided with a hole 3 approximately in the center thereof for discharging air in order to create a negative pressure in the recess 2.

The recess 2 is formed in the shape of a pyramid, and has the large portion 3 at its deepest portion.

A groove 4 is provided on the outside of the central portion of the four sides of the smooth collet 1. The length of one side of the outermost portion of the collet 1 forming the concave portion 2 is approximately equal to the length of one side of the pellet to be sucked.

Next, manufacturing of a semiconductor device using a collet will be explained.

First, a lead frame 8 made of copper is prepared.

Next, solder foil 7 is placed on the portion of lead frame 8 where pellet 6 is to be attached. This solder foil 7 may have any shape, but it is preferable to have a cubic K shape when determining the positional relationship. The solder foil 7 is placed in a positional relationship corresponding to approximately the center of the rectangular bullet 6 when the bullet 6 is attached.

Thereafter, the solder foil 7 is heated and kept in a molten state.

The above-mentioned collet 1 holds the pellet 6 by vacuum suction. This collet l has a groove on the outside of the part facing the center of each side of the semiconductor element, so it is configured so that it contacts the pellet near the four corners, and the length of the collet excluding the grooves is 1 is formed to have the same length as one side of the target pellet, and the periphery of the groove is very close to the target pellet 6, so that the entire surface of the semiconductor element can be protected.

Thereafter, the pellet 6 held by the collet 1 is conveyed to a tab serving as a support substrate of the pellet 6, and the molten solder foil 7 is sandwiched and pressed against the tab to be attached to the support substrate. At this time, the solder 7a protrudes upward from approximately the center of the four sides of the collet, but since the groove 4 is formed, the solder 7a does not adhere to the collet 1.

Once the pellet 6 is pressed by the collet 1, it is separated by stopping the evacuation from the collet 1. At this time, the thickness of the pellet 6 increases due to the surface tension of the solder 7 compared to when the pellet 6 is pressed.

As a result of studies conducted by the present inventors, it has been found that this final thickness can be controlled by adjusting the amount of solder. According to the present inventor, by setting the thickness to 40 μm or more, good effects on the characteristics of the semiconductor element were obtained.

After the semiconductor element is attached in this manner, wire bonding and resin sealing steps, and further cutting of the lead frame, etc., are performed to obtain a semiconductor device with a thick solder layer.

Incidentally, as shown in FIGS. 7 and 8, a highly reliable semiconductor device could be obtained by using the vacuum suction jig of the present invention.

Although the present invention has been described above based on Example K by the present inventor, the present invention is not limited to the above-mentioned Examples.

For example, the shape of the vacuum suction jig may be any shape as long as it has a shape that matches the shape of the target semiconductor element and contacts the four corners. Further, as the conductive adhesive for the semiconductor device using the vacuum suction jig of the present invention, silver paste or other materials may be used. Furthermore, any lead frame can be used, and the collet length 1 excluding the groove part was formed to be almost the same as one side of the target pellet, but it may be made larger as long as the solder does not come into contact with it. You can also make it smaller.

〔Effect of the invention〕

Among the effects obtained by the present invention, typical effects are as follows.

Since a vacuum suction jig that contacts the semiconductor element at four corners is used, it is possible to obtain a collet without adhesion of adhesive even when a large amount of conductive adhesive is used. Furthermore, since there is no adhesive, a collet suitable for mass production can be provided.

[Brief explanation of drawings]

Fig. 1 is a side view of the vacuum suction jig of the present invention, Fig. 2 is a front view thereof, Fig. 3 is a sectional view taken along the line xx' of the vacuum suction jig shown in Fig. 2, and Fig. 4. FIG. 5 is a side cross-sectional view for explaining the case of attaching a pellet using the vacuum suction jig of the present invention, and FIG. 6 is a perspective view showing the case of suctioning a semiconductor element using the vacuum suction jig of the present invention. 7 and 8 are diagrams showing the characteristics of a semiconductor device manufactured using the vacuum suction jig of the present invention.

Claims (1)

[Scope of Claims] 1. A vacuum suction jig for vacuum suctioning a rectangular semiconductor element, characterized in that the semiconductor element contacts only near four corners of the semiconductor element. 2. A vacuum suction jig for vacuum suctioning a rectangular semiconductor element, characterized in that a groove is formed on the outside of a portion facing the center of each side of the semiconductor element.