JPS6050345B2 - Method and device for removing resin burrs from semiconductor devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing resin burrs attached to a lead frame of a semiconductor device and an apparatus using the method.

One of the manufacturing processes for semiconductor devices is a molding process using thermosetting resin.

During this molding, the resin often flows from the position where it is filled and coated to the external lead, resulting in resin burrs after molding. If this burr flows onto the external lead, it will not only significantly impair the solderability of the external lead, but also cause poor electrical contact, corrosion, and oxidation, which will reduce the reliability of the semiconductor device. It has also become a cause of damage.
Conventionally, there have been two methods for combating such resin burrs.

The first method is to modify the lead frame or mold to prevent resin burrs from forming. This method has the disadvantage that it does not fundamentally prevent burr generation due to mold deterioration due to long-term use, limitations in machining accuracy due to enlargement of the mold, or variations in lead frame thickness. Ta. The second method is to remove attached resin burrs using a grindstone, cutter, dry honing, wet honing, brushing, vibration, pressing, coating, ultrasonic waves, pressure, etc. However, dry honing, wet honing, brushing, etc. have disadvantages such as damaging the side walls of the resin-filled coating and significantly impairing solderability. In addition, the method using a rotary grindstone has the drawback that it is difficult to adjust for differences in the amount of wear of the rotary grindstone, and resin burrs may not be removed in some areas or external leads may be excessively removed. Furthermore, with other methods, it was difficult to completely remove resin burrs.
The present invention has been made in order to eliminate the above-mentioned drawbacks, and the present invention has been made to sandwich the external lead portion of a semiconductor device having resin burrs attached thereto between an abrasive grain piece and a pressing body, and to impart relative motion to the external lead portion and the abrasive grain piece. It is an object of the present invention to provide a first invention in which resin burrs are removed using a method of removing resin burrs, and a second invention that utilizes the first invention.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In carrying out the first invention, the following apparatus is used.

That is, as shown schematically in FIG. 1, abrasive grain pieces 2 are fixed to the upper surfaces of a large number of flat grindstones 1 arranged in parallel. A pressing body 3 is fixed to a guide 37 on the upper part of the flat grindstone 1 so as to face the abrasive grain pieces 2. An elastic member 8 such as a spring is inserted into a guide hole (not shown) provided in the guide 3''. The flat grindstone 1 is fixed, the pressing body 3 can move vertically and horizontally, and the pressing force can be adjusted by adjusting the elastic force of the elastic member. In order to remove the resin burr 7 from the outer lead 6 of the lead frame 5 of the semiconductor device 4 to which the resin burr has adhered, the pressing body 3 is raised and the outer lead portion is placed on the grindstone 1. Then, the pressing body 3 is lowered and the pressing force is adjusted to sandwich the external lead portion 6 between the pressing body and the grindstone.

Next, when the pressing body is given horizontal reciprocating motion, the lead frame 5 moves horizontally together with the pressing body, and the tips of the abrasive grain pieces 2 fixed to the upper surface of the grinding wheel 1 become cutting edges and adhere to the external lead part. The plastic burr that has been removed is removed using the principle of cutting action.

At this time, the front of external lead 6. Even if the surface is removed, there is no effect on the semiconductor device. In the above description, the grindstone 1 is fixed, but resin burrs can be removed by giving relative movement to the external lead part, the pressing body, and the abrasive grain pieces. Therefore,
For example, the lead frame 5 and the pressing body 3 may be fixed by moving the grinding wheel 1 horizontally, or a grinding wheel to which abrasive grain pieces are fixed may be used instead of the pressing body 3, and the lead frame is fixed and both grinding wheels facing each other are fixed. It may be moved horizontally, or conversely, the lead frame to which both grindstones are fixed may be moved horizontally. Furthermore, the Z direction, speed of movement, shape, etc. of the grindstone and the pressing body are not limited to those in the above embodiments. Next, an embodiment of the second invention utilizing the first invention will be described in detail with reference to FIG.

In FIG. 2, the same reference numerals are used for parts corresponding to those in FIG. 1. As shown in FIG. 2, the pressing body 3 is fixed to the block 11, and its length corresponds to the width of the lead frame 5.

This block 11 can slide up and down in the groove 15 of the guide 12, and the lowest position is limited by the protrusion 12'' of the guide 12.The upper part of the guide 12 has a screw that can be adjusted. A flat plate 13 to which an adjuster 14 is attached is provided, and the flat plate 13 and the block 11
By inserting a spring 8 between them and rotating an adjuster 14, the elastic force of the spring 8 can be adjusted.
Shafts 16, 16'' are fixed to both ends of the guide 12, and both gate ends of the shafts 16, 16'' are fitted into slide bearings 17 fixed to a bearing holder 18. Further, the guide 12 is formed by an inverted L-shaped connecting plate 21 and a flat plate 13 fixed to the shaft 2' of the air cylinder 20, which constitutes the first drive unit, which is attached to a flat plate 19 horizontally suspended on the bearing holder 18. connected. Further, a crank-shaped connecting plate 22 is fixed to the block 11, and a shaft 23'' of an air cylinder 23 that constitutes a first drive unit attached to the flat plate 19 is loosely inserted into the connecting plate 22. Even if the shaft 23'' rises, the clearance d
The rise of block 11 is delayed accordingly. Air cylinder 2 above
By alternately operating the air cylinders 20 and 23 of the first drive unit constituted by 0 and 23, box feeding movement in the vertical plane can be performed. If a horizontal drive mechanism is provided separately, horizontal movement perpendicular to the box feeding movement can be achieved.

Next, the mounting body and the second drive section will be described. On the mounting body 25, a grindstone 1 having abrasive grain pieces 2 fixed to its upper surface is mounted.

A shaft 27 of a linear bearing 28 is locked to both ends of the mounting body 25 via a flat plate 27''.The linear bearing 28 is fixed with a bracket 29. A rack 30 is fixed to the lower surface of the rack 30, and a pinion 31 that meshes with the rack 30 is provided below the rack 30.This pinion 31 is connected via a belt 32 to a small gear 34 fixed to the shaft of a motor 33. Furthermore, the shaft 1 is located on the lower side of the mounting body 25 near the center.
An air cylinder 10 having a shaft 1 is provided with a horizontal play corresponding to the shaft hole of the air cylinder.

As a result, by alternately operating the motor 33 and the air cylinder 10, it is possible to cause the mounting body to move in a box-feeding motion. Next, the operation of the apparatus configured as described above will be described. A semiconductor device is supplied to the mounting body 25 by a rotor (not shown) in the previous process.

After being supplied, the air cylinder 23 is
operates to raise the block 11. Simultaneously with this operation of the air cylinder 23, the air cylinder 10 operates to raise the mounting body 25, and when the lifting is completed, a signal is issued, the motor 33 is operated, the mounting body 25 is horizontally moved, and stopped at a predetermined position. The mounting body 25 is lowered by the air cylinder 10, and the external lead portion of the semiconductor device is loosely fitted onto the abrasive grain piece 2 on the way.
Next, the air cylinder 23 is operated to lower the block 11 and press the external lead portion 6 into contact. Subsequently, the air cylinder 20 is operated to give horizontal movement to the block 11 to remove resin burrs attached to the lower surface of the external lead portion. At this time, the block 11 and the semiconductor device 26 move together, but in order to ensure this movement, the lead frame 5 may be held down by a guide using a claw or the like. Next, when the above horizontal movement is completed, air cylinder 2
3 is operated to raise the block 11, the motor 33 is operated to transfer the semiconductor device to a device having the same structure as described above, and the resin burr on the other surface of the external lead portion is removed.

In this way, the resin burr attached to the external lead portion is completely removed. In addition, when removing resin burrs,
If the semiconductor device is fixed, a piece of abrasive grain is fixed to the block 11 in the same way as the grindstone 1, and the block and mounting body are given horizontal movement at the same time, the resin burrs on the surface of the external lead part should be removed at the same time. I can do it.

In the first and second inventions, the semiconductor device from which the resin burrs have been removed is passed through a cleaning device and a static electricity removal device, which will be provided next.

First, as shown in FIG. 3, the cleaning device has one end fitted with a radial bearing (not shown) and the other end fitted with a radial bearing and a gear (not shown) at positions facing both sides of the external lead part. A rotating brush 35 fixed to a fitted shaft 36 is provided. The distance between the shafts 36 is equal to the toothing distance of the rotating brush, and by applying rotation of the motor to either one of the two shafts, the brush rotates and cleans the burr dust attached to the external lead portion. Next, the static electricity eliminator can be one configured to ground the lead frame, or a static electricity eliminator manufactured by Scientific Enterprises, Inc., USA, which removes static electricity by blowing air. It should be noted that the second invention is not limited to the above embodiment, and for example, a motor may be used instead of the air cylinder, and the horizontally moving object may be either a grindstone or a semiconductor device. It may be both, or it may be both.

Further, the relative motion between the grindstone and the semiconductor device does not need to be a reciprocating motion, and the semiconductor device may be passed between the two grindstones. As explained above, according to the present invention, since resin burrs can be removed from the base of the resin-filled coating, solderability is significantly improved, and costs can be reduced by reducing the number of soldering steps.

Furthermore, since poor electrical contact, corrosion, and oxidation are eliminated, the reliability of the semiconductor device is improved. Furthermore, compared to other devices, it is possible to provide a simple and inexpensive device that requires less adjustment.

[Brief explanation of the drawing]

FIG. 1 is a schematic route map for explaining the first invention;
The figure is a sectional view showing an embodiment of the second invention, and FIG. 3 is a schematic diagram of the cleaning device. 1...Whetstone, 2...Abrasive grain piece, 3...
... Pressing body, 6 ... External lead part, 7 ... Resin burr, 10, 20, 23 ... Air cylinder, 11
...Block, 25 ... Placement body, 26
・・・・・・Semiconductor device.

Claims (1)

[Claims] 1. When removing resin burrs from the external lead portion of a semiconductor device to which the resin burr has adhered, the external lead portion of the semiconductor device to which the resin burr has adhered is held between abrasive grain pieces and a pressing body. A method for removing resin burrs from a semiconductor device, characterized in that resin burrs are removed by applying relative motion to the external lead portion, the pressing body, and the abrasive grain pieces. 2. A pressing body that can adjust the contact pressure, a first drive unit that gives horizontal and vertical movement to this pressing body, a mounting body provided with abrasive grain pieces installed opposite to the pressing body, and this mounting body. 1. A device for removing resin burrs attached to a lead frame of a semiconductor device, comprising: a second drive section for imparting horizontal and vertical motion to a mounting body.