JPS58218136A - Die collet for semiconductor device - Google Patents

Abstract

PURPOSE:To facilitate to mount a die of a size larger than conventional ones by the collet of the same size as conventional die collets by notching the corner sections of a die chuck section in the die collet used in a die bonding process. CONSTITUTION:The die 2 is adsorbed through decompression and held in the die absorbing section 11a by a decompression introducing path 1b in the collet 11. The collet 11 takes an octagonal columnar type obtained by notching the corner sections of a square columnar type in size such as 0.5-1.0mm. or less. That is, notch surfaces 11b, 11b... are formed through notching, but notch length may be slightly larger than the depth of the cavity of a lead frame. The shapes of the notch surfaces do not necessarily take planes, and it is of course that they are notched in curved surfaces and the collet may take a shape close to a column. The trouble of air leakage in case of decompression adsorption by notching is solved by increasing the speed of exhaust of decompression by approximately 10%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improved structure of a die collet used in a semiconductor device mounting process.

[Technical background of the invention]

In recent years, semiconductor device manufacturing technology has shown particularly remarkable development. This is due to the results of ultra-fine processing technology typified by 64KRAM, and although the degree of integration of semiconductor elements (dies) formed using these technologies is extremely high, the chip size has increased in proportion to the number of pins. Often. However, there is a tendency for packages for mounting and protecting dies to become smaller and smaller in order to increase packaging density on substrates. There is a strong demand for the miniaturization of this ξ cage, especially in the width direction, and in 1974, the suitable size of 0.6 mil became available in the market as 0.5 mil, 0.4 mil, and 0.3 mil. The demands are becoming increasingly strict.

Conventionally, a semiconductor device has been formed by bonding a die to an island of a lead frame, and then connecting its electrodes to the leads of the lead frame by wire bonding, followed by transfer molding with epoxy resin. Next, a method for bonding the die to the lead frame will be described in detail.

In the method of bonding a die to a lead frame with, for example, solder, the lead frame is heated in advance to 200 to 450°C (depending on the type of solder and adhesive), and solder is placed in the center of the island. Next 1
The die (2) is inserted into the vacuum introduction path (1b) in the die adsorption part (1a) of the collet (1) shown in Figs. 1 to 3 (Figs. 1 and 2 show the die adsorption part of the collet). ), the solder is vacuum-adsorbed and held, transported onto the solder, pressed into contact with the solder, and then scrubbed and bonded. Thereafter, as described above, the semiconductor device is formed through wire bonding and molding.

[Problems with background technology]

The conventional technique of tilting has the following problems.

As shown in FIG. 4, the island (3a) of the lead frame (3) is surrounded by inner leads (3b).

(3b) A cavity (depth t) is formed in a region connecting the inner ends of... (3b). However, from the viewpoint of bonding performance, reliability, and processing surface, the inner lead has four corners (4a) to (4d) of the cavity formed at each inner end of the inner lead of 0.5 to 0.5.
0.8 rrm RK is about to be rounded. Therefore, the collet (1) for mounting (scrubbing) the die (2) on the eyelend (3a) at the bottom of this cavity is 4
It is a prismatic type, and considering the margin for scrubbing the collet on the mount, the positioning accuracy, etc., the size of an example of the die adsorption part (1a) (of the collet) shown in Figure 5 is 4.54 m @ X 8. .Die that can be bonded between 20 (
For 2), the limit is 3.35ii x 5°61 fights. However, if the island in the lead frame is placed on the same plane as the inner lead, wire bonding performance and reliability will be affected, so it may be necessary to change the size of the package or use a package made of other expensive materials. There were problems such as the need to

[Purpose of the invention]

The present invention provides a collet shape that can be bonded to a lead frame with a die of a larger size than previously available.

[Summary of the invention]

The die collet for semiconductor devices according to the present invention is characterized in that the die collet used in the die bonding process in noodle making of semiconductor devices has a corner portion of the die chuck portion cut out.

[Embodiment 5 of the Invention A die collection of one embodiment is shown in FIGS. 6 to 8. In the figure, aυ is the collet and its die adsorption part (ll
The die (2) is held in a) by being adsorbed under reduced pressure by the reduced pressure introduction path (1b). Here, the collet aυ has a rectangular prism-shaped corner with an example of 0.5 to 1. , Q am has an octagonal prism shape with a notch below. In other words, the notched surfaces (llb), (llb), . . . are essential parts of the present invention, and the notch length may be slightly larger than the depth of the cavity of the lead frame. Next, the shape of the cutout surface is not necessarily limited to a flat surface, and it goes without saying that the collet may be cut into a curved surface so that the collet has a shape close to a cylinder. Incidentally, the problem of near leakage in vacuum adsorption through the notch can be solved by increasing the vacuum pumping speed by about 10 inches.

Next, although the present invention has been described with respect to the lead frame of the above embodiment, it can be similarly applied to a ceramic package having a cavity. In addition, when the die is square, the notch shape is shown as an example in which the cutout is made at 45 degrees on the diagonal line of the collet according to the die size, but the shape is not limited to this.If the die is rectangular, the die size 2 due to the cage
The angle may be suitably selected within the range of about 8° to 45°.

〔Effect of the invention〕

According to this invention, there is a remarkable effect that a die of a larger size than conventionally can be mounted using a collet of the same size as conventionally. That is, an explanation will be given with reference to FIG. 9, which shows one embodiment of a collet having the dimensions of the conventional example described with reference to FIG. 5 in the section on problems in the background art. In this case, the dimensions of the die that can be supported and mounted are 3.74 x 7
．． 10 m, which has the very remarkable advantage of being about 20% larger in area. Further, FIG. 10 shows the correlation between the package size and the die size that can be assembled into the package, in comparison with the conventional example. In the figure, (5) is conventional, (B) is 1
Examples are shown below. This also results in an increase of approximately 7% on each side of the square.

[Brief explanation of the drawing]

Figures 1 to 3 show a conventional collet, Figure 1 is a perspective view, Figure 2 is a front view, Figure 3 is a sectional view taken along line xX' in Figure 2, and Figure 4 is a lead frame. FIG. 5 is a front view showing the conventional relationship between the cavity of the lead frame, the collet, and the die, and FIGS. 6 to 8 show the collet of one embodiment, and Fig. 6 is a perspective view, Fig. 7 is a front view, Fig. 8 is a sectional view taken along the line YY' in Fig. 7, and Fig. 9 shows the relationship between the cavity of the lead frame, the collet, and the die in one embodiment. Front view, No. 10
The figure is a diagram showing the correlation between package size and die size. 2 Die 11 Collet 11a (of the collet) Die suction part 11b (of the collet) Notch surface agent Patent attorney Inoue-O No. I Fig. 2 Fig. 3: ゛: Fig. 4 Fig. 5 Fig. 6 Fig. 6 7 Figure 8

Claims (1)

[Claims] A die collet for semiconductor devices, characterized in that the rectangular die collet used in the die bonding process in the manufacture of semiconductor devices has a corner portion of a die chuck portion cut out.