JPS6250227B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seam weld device, and more particularly to a seam weld device used for sealing an envelope covering a circuit element in the manufacture of semiconductor devices, semiconductor integrated circuit devices (ICs), and the like.

As is well known, semiconductor devices are sensitive to the effects of the outside world, so semiconductor devices are covered with an envelope (also called a package) to improve airtightness and prevent deterioration of the characteristics of the semiconductor device. By the way, as one of the sealing techniques, a rectangular cap is superimposed on the envelope body, and electrodes made of rollers are moved while contacting and energizing two corresponding parallel edges of the cap, and the cap is connected to the envelope body. At the same time, after welding on two sides is completed, welding is carried out while moving the electrodes to the other two parallel sides while contacting and energizing them. A so-called parallel roller seam welding method is known.

However, this welding method requires two welding operations and also requires the cap to be rotated 90 degrees after the first welding operation, resulting in low workability. In addition, in order to improve work efficiency, two welding devices are prepared, and one welding device is used to connect two parallel caps.
There is also a method of welding one side and then using the other welding device to weld the other two parallel sides of the cap, but this increases equipment costs and does not improve work efficiency as much as expected.

In addition, in this parallel roller seam welding, current flows at the same time as the electrode contacts the cap edge.
It is necessary that the current be turned off as soon as the electrode leaves the cap edge. That is, if a current flows before the electrode contacts the cap edge or after the electrode leaves the cap edge, a discharge phenomenon will occur between the electrode and the cap edge, causing discoloration of the corners of the cap and discoloration. A good product is produced. Also, if the time from when the electrode contacts the cap edge until the current flows, or if the current is cut off before the electrode comes off from the cap edge, there will be parts that are not welded, resulting in a product with poor airtightness. is created.

Therefore, an object of the present invention is to provide a seam welding device that does not cause sealing defects or appearance defects.

Another object of the present invention is to provide a seam welding device that requires short welding time.

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

FIG. 1 shows an embodiment of the seam welding device of the present invention. As shown in the figure, there is shown a table 3 on which an envelope body 1 and a cap 2 to which semiconductor elements and the like are attached are placed. This table 3 is rotated by a motor 4. On the other hand, a pair of opposing electrodes 5 and 6 are arranged above the table 3. A rack 10 is provided on the horizontal portion 9 of the support arms 7, 8 of these electrodes 5, 6. Pinions 11 that mesh with this rack 10 are attached to rotating shafts of control motors 12 and 13, respectively. Therefore, the pair of electrodes approaches or retreats toward the center of the table. Furthermore, although the table 3 rotates at a constant speed, the rotational speed of the control motors 12 and 13 for moving and adjusting the electrodes 5 and 6 is determined by the rectangular shape of the cap 2 placed on the table 3, that is, the rectangular shape. Determined by short side, long side, etc. In other words, as shown in Fig. 2, the electrodes 5 and 6 only move on the X-axis, and as the cap 2 rotates in the direction of the arrow, the coordinates around the cap 2 that intersect with the X-axis change every moment. do. Therefore, always electrodes 5, 6
The control motors 12 and 13 are controlled so that the cap 2 contacts the periphery of the cap 2.

Next, we will explain the sealing (welding) method using such a seam welding device.
At the same time, the rectangular cap 2 is superimposed on the envelope body 1 and fixed so as not to move. Incidentally, a rectangular frame portion on the upper surface of the envelope main body 1 and the cap 2 (not shown) are formed of a conductive material. Thereafter, a pair of electrodes 5 and 6 are brought into contact with the long sides of the cap 2, for example, as shown in FIG. Then, by applying a voltage between these electrodes 5 and 6 after contact, the contact portions of the cap 2 and the envelope body 1 are heated by resistance and welded together.
Further, while applying a voltage, the table 3 is rotated half a turn (180 degrees) to weld the entire circumference of the cap 2 and the envelope body 1. When the sealing is completed, the current is turned off, and then the electrodes 5 and 6 are separated from the cap 2. In reality, after contacting the electrode with the cap, the cap is rotated until it reaches a certain rotational position, then a current is applied, and the cap is rotated from this position.
It is energized only for 180 degrees + α. Then, after turning off the current, remove the electrode from the cap.

According to such an embodiment, reliable sealing can be achieved simply by once setting the electrode on the cap and rotating the cap. Therefore, the sealing time can be shortened compared to the conventional method, and work efficiency can be improved.

Further, in this embodiment, no voltage is applied when the electrode is not in contact with the cap. For this reason,
No discharge occurs between the cap and the electrode. Therefore, discoloration defects due to discharge as in the conventional case do not occur.

Furthermore, in this embodiment, the current is applied to cap 2.
Since this is done while rotating by 180 degrees + α, there is no unwelded part like in the conventional method.

Note that the present invention is not limited to the above embodiments. For example, in order to perform uniform welding around the entire circumference of the cap, if welding conditions at each part of the cap wire of the electrode, in other words, a means of keeping the contact movement speed of the electrode with respect to the cap constant, are adopted,
It is possible to achieve reliable sealing and shorten the work time (speed up). That is, when the table is rotated at a constant speed, the contact time between the electrode and each part of the cap line differs. Under the conditions that each part of the cap can be reliably welded, the contact time of the electrodes may be too long depending on the location. However, in the case where the contact time of the electrodes at each part is constant, the maximum speed at which bonding can be ensured may be used as a reference, so that the working time can be further shortened. Further, the rotation of the table can be controlled by inputting the lengths of the long sides and short sides of the cap, the shape of the electrodes, etc. to a microprocessor, automatically processing the calculations, and controlling the motor 4 with the output thereof.

Furthermore, it goes without saying that the present invention can be applied to things other than manufacturing semiconductor devices.

As described above, according to the seam welding device of the present invention, a rectangular cap can be easily sealed to the envelope main body in a short time, so that the efficiency of the sealing work can be improved.

Furthermore, according to the present invention, welding can be started from any location on the cap, and there is no need to securely position the electrode at the corner of the cap unlike in the past, so the operation is simple and the discharge It has many effects such as no discoloration defects or unwelded defects caused by the welding process.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a seam welding device according to an embodiment of the present invention, and FIG. 2 is an explanatory plan view showing the relationship between electrodes and caps in the device of FIG. 1. 1... Envelope body, 2... Cap, 3... Table, 4... Motor, 5, 6... Electrode, 7, 8
... Support arm, 9 ... Horizontal part, 10 ... Rack, 11 ... Pinion, 12, 13 ... Control motor.

Claims (1)

[Claims] 1 A method comprising: a pair of electrodes; means for bringing both electrodes into contact with a workpiece; means for rotating the electrodes or the workpiece; and means for changing the distance between the electrodes along with the rotation. seam welding equipment.