JPH0452617B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a pellet mount device used in the manufacturing process of semiconductor devices.

[Technical background of the invention]

In the manufacture of semiconductor devices, a wafer that has undergone wafer processing and testing is separated into individual packages by dicing to form pellets, and the pellets are mounted on a lead frame. A pellet mounting device is used to load the pellets. Circuits formed on wafers do not have good parts at the front, and contain a large proportion of defective parts.In order to efficiently mount good pellets, the following types of pellet mounting equipment have traditionally been used. ing.

The first type is used when the rate of good pellets is not very high. After transferring only good pellets to a container called a tray, the pellets are taken out one by one using a suction nozzle, and the pellet position correction mechanism is used. The position of the pellet is corrected, and the pellet is transferred to a predetermined position on the lead frame and mounted.

The other one is of the type shown in Fig. 1, in which a cassette ring 4 to which pellets 2 from which wafers have been separated is attached via an adhesive sheet 3 is attached to an -Y stage 5
It has a pellet take-out section 1 placed on an upper cassette ring holder 6, and a pellet position correction section 10 for correcting the position and rotational deviation of pellets 2 sucked by a suction nozzle 15.
The pellet take-out section 1 is equipped with a push-up mechanism having an arm 7 that moves a push-up needle 8 up and down from below the cassette ring 4 in order to facilitate the take-out of desired pellets. Pellet position correction unit 10
In the above, correction claws 11a and 11b are used to correct the X-direction positional deviation, Y-direction positional deviation, and rotational deviation of the pellets taken out from the pellet removal section 1.
These correcting claws 11a and 11b sandwich the pellet 2 to correct the position. There are two types of correction claws: one that pinches from four sides, and the other that pinches from two sides, as shown in FIGS. 4 and 5, which simultaneously positions two sides of the pellet and their included angles. The positioned pellet is sucked by another suction nozzle 16, and the lead frame 21
is carried to a predetermined position on the stage 20 that supports the
The pellets are loaded onto the lead frame by the descent of the suction nozzle.

[Problems with background technology]

However, in such a conventional pellet mounting apparatus, the X-Y stage of the pellet take-out section needs to move an amount corresponding to the size of the wafer. In recent years, there has been a trend to increase the size of wafers to improve productivity, and 4-inch (101.6 mm) and 5-inch (127 mm) wafers are becoming the standard. As the wafer becomes larger in this manner, the amount of movement of the X-Y stage also increases, and accordingly, the mechanical section becomes larger, which increases the overall size of the apparatus and is disadvantageous in terms of accuracy.
Therefore, there is a problem in that the equipment cost increases, leading to an increase in product cost.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a pellet mount device in which the overall size of the device does not increase even when the wafer diameter increases.

[Summary of the invention]

In order to achieve the above object, in the pellet mounting device according to the present invention, the X-Y
A rotation mechanism is added to the stage to reduce the movement range of the X-Y stage so that it scans a range divided into multiple parts of the wafer, and a pellet position correction unit is installed to compensate for the amount of rotation of the X-Y stage. A rotation mechanism is added to give rotation to the device, making it possible to downsize the device.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 2 to 5.

FIG. 2 is a front view showing the pellet take-out section 30, and as in the case of FIG.
This cassette ring 33 is attached to the X-Y stage 3 through
4 is attached to the cassette ring holder 35 on top of the cassette ring holder 35. The X-Y stage 34 consists of an X-direction stage 35 driven by a motor 36, a Y-direction stage 37 driven by a motor 38, and a rotation stage 39 driven by a motor 41 via a gear 40. . Since the outer peripheral end surface of the rotary stage 39 is formed with a tooth profile that meshes with a gear 40, the cassette ring holder 35 and the pellets 31 can be rotated by driving the motor 41.

By employing this rotary stage, the pellet removal range can be narrowed. That is, as shown in FIG.
The pellets 31 fixed on the cassette ring 33 placed on the cassette ring 33 are divided into four pellet groups A, 90° each, passing through the center 0 of the pellets.
If B, C, and D are determined, then in order to take out the pellets of this wafer by the suction nozzle 45,
-The range in which the Y stage should move should include only the area A. After the pellet removal in area A is completed, rotate the rotary stage,
As shown in FIG. 5, area B is placed at the extraction position. With such four divisions, the movement range of the X-Y stage can be halved in both the X and Y directions.

In order to facilitate taking out the pellets, a push-up mechanism is provided having an arm 42 for vertically moving a push-up needle 43 from below the cassette ring 33, as in the conventional example.

FIG. 3 is a sectional view showing the details of the pellet position correcting unit 50 which is a part of the pellet mounting device according to the present invention. Correcting claws 53a and 53b for pellet positioning are adapted to slide, and the positional deviation of the pellet 31 placed on the pellet table 54 can be corrected. This pellet table 54 has a vacuum hole 55 at its center, is rotatably supported on the support plate 51 via a bearing 56, and is connected to a timing pulley 58 and a vacuum source (not shown) at the bottom thereof. It has a joint 57 for this purpose. The timing pulley 58 is connected by a timing belt 61 to a timing pulley 60 which is connected to a motor 59 attached to the support plate 51. Thereby, the pellet table 54 can be rotated in accordance with the rotation of the motor 59. This amount of rotation is equal to the angle through which the rotary table was rotated in FIG. That is, a signal proportional to the amount of rotation of the rotation stage 39 is extracted, and a control device (not shown) controls the pellet 31.
After the pellets are placed on the pellet stand, the motor 59 of the pellet position correction section 50 is given reverse rotation to compensate for the amount of rotation of the rotary stage 39. As a result, the pellet position can be corrected in the same manner as usual without being affected by the amount of rotation of the rotary stage.

To explain the operation of the pellet mount apparatus as described above, first, the cassette ring 33 is positioned so that the center of the wafer and the center of the rotation stage coincide. If the wafer is divided into four parts, the X-Y stage moves in the X and Y directions each time a pellet is taken out so that the tip position of the suction nozzle 45 scans the position A in FIG. At the same take-out position, the suction nozzle 45 descends to adsorb the pellet, pulls it up and transfers it to the pellet position correction section 50, and descends to adsorb the pellet onto the pellet stand 54. Note that when taking out the pellets, the pellet pushing up needle pushes up the pellets from below, making it easy to take out the pellets.

The pellet table 54 that has attracted the pellets is rotated by the rotation amount of the rotation stage 39 via the timing pulley 60, timing belt 61, and timing pulley 58 due to the rotation of the motor 59 which receives a signal corresponding to the rotation amount of the rotation stage 39 from the control device. Rotate in the opposite direction by the angle of . For example, when taking out pellets in area B with the rotary stage rotated 90 degrees with respect to the reference position as shown in FIG. Normalize the situation. Similarly, when the rotation stage is rotated 180 degrees to take out pellets in area C, the pellet table 54 is rotated 180 degrees in the opposite direction.
When the rotary stage is rotated 270 degrees to take out pellets in area D, the pellet table 54 may be rotated 270 degrees in the opposite direction.

After correcting the rotational position of the pellet table, the correction claw 53a
and 53b move to perform accurate positioning, and after the positioning is completed, it is carried onto the lead frame by another suction nozzle 46.

In the above embodiments, the pellet take-out area is set to 1/4 of the wafer, and the rotation stage and pellet table are rotated and reversed by an integral multiple of 90 degrees, but the pellet extraction area is not limited to this, and any arbitrary It is possible to divide into multiple areas. However, even if the stage is divided into four or more parts, the amount of movement of the X-Y stage does not decrease much, so the case of dividing into four parts has the greatest effect.

Furthermore, the rotational drive of the rotation stage and pellet table is not limited to the method of the embodiment.
Any rotational drive method can be employed.

Furthermore, in order to compensate for the amount of rotation of the rotary stage in the pellet extraction section, it is possible to rotate the rotary stage in the opposite direction by the same angle as in the example, or to rotate the rotary stage in the same direction by (360° - α) with the rotation angle of α being α. You can also rotate it.

〔Effect of the invention〕

According to the pellet mounting device according to the present invention as described above, the cassette ring on which separated pellets are placed in the pellet take-out section is rotated by angles divided into equal angles including the center of the wafer; X within the range of multiple divisions
It is equipped with an X-Y stage that can move in both the X-Y direction and the Y-direction, and the pellet position correction section is equipped with a rotation mechanism that reversely rotates the pellet by the amount of rotation of the rotation stage when taking out the pellet.
The range of movement of the stage can be reduced, and therefore the overall size of the equipment can be reduced even when large-diameter wafers are used, thereby suppressing increases in equipment costs and ultimately reducing product costs. can.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an outline of a conventional pellet mount device, Fig. 2 is a front view showing a pellet take-out section in a pellet mount device according to the present invention, and Fig. 3 shows the structure of a pellet position correction section. The partially sectional view shown, and FIGS. 4 and 5 are plan views showing pellet removal in the pellet removal section. 30... Pellet removal section, 31... Pellet,
33... Cassette ring, 34... X-Y stage, 39... Rotating stage, 36, 38, 41,
59...Motor, 50...Pellet position correction unit,
54...Pellet stand, 58, 60...Timing pulley, 61...Timing belt.

Claims (1)

[Claims] 1. A pellet take-out section that sequentially takes out pellets separated from wafers by dicing from a cassette ring in which they are placed and transfers them using a suction nozzle;
A pellet mounting device comprising a pellet position correction section that corrects the position of the transferred pellets, and a mount section that transfers the pellets whose position has been corrected using another suction nozzle and mounts them at a predetermined position on the lead frame, The section includes a rotation stage that rotates the cassette ring at each angle divided into a plurality of equal angles including the center of the wafer, and an X-Y stage that is movable in the X direction and the Y direction within the range of the plurality of divisions. A pellet mounting device, characterized in that the pellet position correction section includes a rotation mechanism that applies a rotation to the pellet to compensate for the amount of rotation of the rotation stage when the pellet is taken out.