JPS5917849B2 - How to recycle semiconductor devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for remanufacturing a semiconductor device equipped with a beam lead integrated circuit.

Recently, with the increase in the density of semiconductor devices, many devices have a plurality of beam lead integrated circuits mounted on the same substrate.

FIG. 1 and FIG. 2 show an outline of such a semiconductor device,
1 is a beam lead integrated circuit; 2 is a plurality of beam leads protruding from the periphery of the front side; 3 is a substrate made of ceramic or other material; and a conductive pattern 4 is coated on the substrate to form a desired circuit. It is worn. As is well known, Beam Lead 2 has the advantages of being chemically stable, soft and easy to bond.
Those mainly based on u) are used. 5. A large number of integrated circuits 1 are mounted on the substrate 3, and the conductive pattern 4 of the mounting portion has the same pattern as the beam lead protrusion pattern from the integrated circuits 1.

Therefore, when installing, place the integrated circuit 1 face down, that is, with the surface side of the integrated circuit 10 on which circuit elements are formed facing down, and align the beam lead 2 with the conductive pattern 4 to complete the positioning of all beam leads with the conductive pattern. However, by performing bonding, for example, by thermocompression in such a state, all the beam leads can be simultaneously attached to the conductive pattern 15, and thus the integrated circuit 1 can be attached to the substrate 3. As described above, if a semiconductor device with a large number of integrated circuits mounted on the same substrate is incorporated into a computer and some of the integrated circuits become malfunctioning for some reason, it will naturally be replaced. However, in this case, if the entire semiconductor device containing a large number of integrated circuits is replaced,
As the cost increases, it is necessary to remove the defective integrated circuit and replace it with a new good integrated circuit.

For this replacement, the beam leads of the defective integrated circuit that has been bonded can be completely cut off using a cutter 5, for example, as shown in Figure 3, the integrated circuit can be removed, and a new integrated circuit can be bonded to that part. However, the remaining portion 2a of the cut off beam lead is attached to the conductive pattern part from which the defective integrated circuit has been removed, as shown in FIG.
If this is not removed, beam lead bonding of the new integrated circuit cannot be performed reliably as desired. When attempting to remove the remaining portion of the beam lead again using a cutter, the beam lead is mostly made of gold (Au) and is soft, so some of the remaining parts of the beam lead stuck to the conductive pattern may form whiskers when cut with the cutter. There is a risk of short circuits occurring between the lines.

The present invention proposes an effective and appropriate method for removing the beam lead remaining on this conductive pattern. The present invention relates to a method for remanufacturing a semiconductor device in which a plurality of integrated circuits are mounted on a common substrate on which a conductive pattern is formed by bonding their beam leads to the conductive pattern. The remaining part of the beam lead stuck to the conductive pattern is removed from the conductive pattern using a vibrating cutter, and a good integrated circuit is attached to the remaining part by beam lead bonding. Next, this will be explained in detail with reference to an embodiment. Fig. 5 shows an embodiment of the present invention, in which 2a is the remainder of the beam lead as described above, 3 is a substrate, and 4 is a conductive pattern. It is.

Reference numeral 6 denotes a fixing table, which is equipped with a vacuum chuck 6a, and the substrate 3 is fixed to the fixing table 6 by this vacuum chuck 6a.

The fixed base 6 can move on the base 9 in the horizontal direction in the drawing. Reference numeral 7 denotes an ultrasonic vibrating device, which includes a vertical adjustment mechanism (not shown) and a vibrating mechanism 8. The vibrating mechanism 8 includes a vibrator 8a and a coil 8b that receives an ultrasonic signal and vibrates the vibrator.

A cutter 5 is attached to the tip of the vibrator 8a. Next, the operation of this device will be explained.

First, the board 3 from which the defective integrated circuit has been removed is placed on the fixing table 6, and the board is suctioned and fixed to the fixing table by the vacuum chuck 6a, and the remaining lead piece 2 to be scraped off by moving the fixing table 6.
A plurality of end faces of a can be brought into contact with the cutter 5. The cutter 5 descends vertically from the tip of the vibrator 8a, and its tip position can be adjusted accurately by operating a fine adjustment screw (not shown) of the vertical adjustment mechanism of the ultrasonic vibrator 7. Therefore, the cutter 5 is set at a height such that its tip is in contact with the conductive pattern 4 or faces the conductive pattern 4 with a small distance therebetween. In this state, the coil 8b is energized to ultrasonically vibrate the vibrator 8a and the cutter 5, and the fixed base 6 is moved in the direction of the ultrasonic vibrator 7. As a result, a plurality of beam lead remaining portions 2a are removed from the end face by the cutter 5.
It is pressed into contact with the body and removed by ultrasonic vibration. The number of remaining beam leads to be simultaneously removed by the cutter 5 is determined according to the width of the cutter 1, so it can be appropriately selected by changing the width of the cutter.

After repeating the same operation as above to remove the remaining beam leads on all four sides, place a new good integrated circuit in the position of the removed defective integrated circuit, align the beam lead with the conductive pattern, and then bond by thermocompression, etc. Bonding and complete the exchange. In this way, according to the present invention, the remaining portion of the beam lead can be removed without damaging the conductive pattern on the substrate, a good integrated circuit can be installed in the position of the defective integrated circuit, and a failed semiconductor device can be regenerated any number of times.

This method is simple because it only applies vibration to the cutter, and it does not cause the remaining beam lead to stretch partially and cause a short circuit between the terminals, as would be the case if the beam lead was simply cut with the cutter without applying vibration. There is no need to worry, and the remaining beam lead can be reliably removed to perform reliable repair. Instead of cutting off the remaining part of the beam lead with a cutter applied with ultrasonic vibrations: By making the cutter blade part flat and pressing it against the remaining part of the beam lead from above and applying ultrasonic vibrations, the beam can be removed. The remainder of the lead may be flattened. In this case, the beam lead of the good integrated circuit can be bonded to the conductive pattern via the flattened remaining beam lead of the defective integrated circuit, and the damaged semiconductor device can also be regenerated. Further, the vibration applied to the cutter does not necessarily have to be ultrasonic vibration, as long as the frequency is considerably high, a similar effect can be obtained.

[Brief explanation of the drawing]

1 and 2 are a plan view and a cross-sectional view showing a part of a semiconductor device equipped with a large number of integrated circuits, FIGS. 3 and 4 are cross-sectional views illustrating the process of removing defective integrated circuits, and FIG.
The figure is an explanatory diagram of an embodiment of the present invention. 1: integrated circuit, 2: beam lead, 2a: remainder of beam lead, 3: substrate, 4: conductive pattern, 5: cutter, -
6: Fixed base, 6a: Vacuum chuck, 7: Ultrasonic vibration, 8
: Vibration mechanism, 8a: Vibrator, 8b: Coil, 9: Base.

Claims (1)

[Claims] 1. In a semiconductor device remanufacturing method in which a plurality of integrated circuits are mounted on a common substrate on which a conductive pattern is formed by bonding their beam leads to the conductive pattern, a defective integrated circuit is attached to the common substrate. The beam lead is cut and removed from the conductive pattern, the remaining beam lead stuck to the conductive pattern is removed from the conductive pattern using a vibrated cutter, and a good integrated circuit is attached to the trace by beam lead bonding. Method for recycling semiconductor devices. 2. The method for regenerating a semiconductor device according to claim 1, wherein the vibration applied to the cutter is an ultrasonic vibration.