JPH0158658B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for aligning a wafer, and particularly to aligning a plate-shaped body having a notch for alignment on one side.

In the manufacturing process of semiconductor devices, an orientation hole, which is a cutout in a part of the semiconductor wafer, is used to align the surface of the semiconductor wafer on which electrodes are formed. A flat (hereinafter abbreviated as OF) is formed, and this O.
The semiconductor wafer is positioned by bringing F into contact with the reference pin.

However, the conventional reference pin is
Since the method of positioning by bringing the OF into contact has a complicated structure, there is a need for an easier method of positioning.

[Conventional technology]

FIG. 6 is a perspective view showing an example of a conventional method for positioning the OF of a semiconductor wafer using reference pins, which is used, for example, when performing photolithography.

OF part 2 placed on the surface of alignment table 1
A semiconductor wafer 3 (indicated by a dotted line in the figure) having an OF
When the OF part of the semiconductor wafer is detected by the detector 7, the rotation of the rotary motor 6 is automatically stopped by the control device, and the external force f is activated to move the semiconductor wafer to the three positioning pins 4, 5, and 8. Positioning is done by pressing.

Another method is to center the semiconductor wafer, then rotate the semiconductor wafer on an axis made of a vacuum chuck, detect the OF using the detection method described above, and control the rotation. be.

A common drawback of these devices is that they are mechanically complex, and if the alignment table on which the semiconductor wafer is placed is movable, positioning becomes even more difficult.

[Problem that the invention seeks to solve]

The problem with the semiconductor wafer positioning method with the above configuration is that the structure is complex and the positioning accuracy is low, resulting in problems such as reduced efficiency and defective products in the semiconductor wafer manufacturing process. will occur.

[Means for solving problems]

The present invention provides a method for aligning wafers that solves the above-mentioned problems. A wafer having a notch is floated by an air nozzle and conveyed to the rotor, the plate is rotated by the roller to align the notch with the reference plate, and then the rotor and the reference plate are is temporarily removed, and the plate-shaped body suspended by the vacuum chuck is moved slowly by vacuum suction and release from the vacuum intermittently on the alignment table, and the wafer is moved to the position of the reference pin. This can be achieved by a method of positioning plate-like bodies, which is characterized in that the plate-shaped bodies are arranged in the same direction.

[Effect]

In the present invention, an air nozzle installed on an inclined alignment table transports a floating semiconductor wafer to a rotor and a reference plate to bring them into close contact with each other, and then the rotor rotates the semiconductor wafer to remove a notch. In order to align the semiconductor wafer with the reference plate and transfer it from that position to the reference pin position while maintaining the direction of the notch, vacuum suction with a vacuum chuck and vacuum release are performed intermittently. This method is designed to slowly move the semiconductor wafer on an inclined alignment surface to align the semiconductor wafer with the reference pins.

〔Example〕

FIG. 1 is a perspective view for explaining an embodiment of the present invention.

There is an inclined alignment plate 11, and a guide 12 on the surface of which the semiconductor wafer 3 is transported.
There are three reference pins 13, 14, and 15 implanted with which the semiconductor wafer 3 having a thickness of about 0.6 mm is finally positioned by the alignment plate 11.

On the alignment table 11, a plurality of air nozzle holes 16 that eject air with a hole diameter of about 0.5 mm and a pressure of 3 kg/cm ² are arranged in multiple rows at predetermined intervals. It has an inclination of approximately 30 to 45 degrees with respect to the surface.

Also, the diameter is 2 to 3 mm and the vacuum suction pressure is 400 Torr.
A vacuum chuck 17 of approximately the same size is provided approximately at the center of the reference pin.

The rotor 18 has a rotating shaft diameter of about 6 mm, is parallel to the reference pins 13 and 14, and has a parallelism tolerance of 1/1000 mm.The rotor 18 is attached to the same frame 20, and is attached to the same frame 20. is operated by a mechanism 21 that can be raised and lowered.

The OF detection device 22 is an optical detection device for finally checking the accurate alignment state of the OF section.

FIG. 2 is a schematic plan view for explaining how the semiconductor wafer 3 is rotated by the rotation of the rotor 18 to align the OF part 2 of the semiconductor wafer 3 with the reference plate 19, and FIG. 3 is a schematic plan view of the air nozzle. In this cross-sectional view, d=about 0.5 mm and α=30 degrees to 45 degrees.

FIG. 4 is a cross-sectional view of the vacuum chuck, where D=
It is 2 to 3 mm.

FIGS. 5a to 5f are schematic sectional views for explaining the functions of the present invention.

In FIG. 5a, an alignment table 11 is placed on the surface of which a semiconductor wafer 3 is placed, and this semiconductor wafer 3 is levitated by the air pressure p as indicated by the arrow ejected from an air nozzle 16, and is normally 0.3 m above the alignment table 11. It levitates to a height of ~0.5mm and moves in the direction of the arrow.

FIG. 5(b) shows that the moved semiconductor wafer is rotated by the frame 20 equipped with the rotor 18 and the reference plate 19, and the OF part is detected and the semiconductor wafer is rotated.
This is a state in which the direction of the OF section has been determined.

FIG. 5c shows that the semiconductor wafer is placed in the vacuum chuck 17.
At the same time, the frame 20 is moved upward as shown by the arrow and removed.

FIG. 5d shows a state in which the vacuum chuck 17 is temporarily released from the vacuum in order to gradually bring the semiconductor wafer, whose direction of the OF part has been determined, closer to the reference pins 13, 14, 15, and the semiconductor wafer is placed on the alignment table. Due to the inclination of the plane and the buoyancy force of the air nozzle, the position of the reference pin is slightly approached.

In FIG. 5e, the semiconductor wafer is once again attracted and fixed by the vacuum pressure P of the vacuum chuck 17.

FIG. 5f shows that the semiconductor wafer whose OF position has been positioned in this way is gradually moved closer to the reference pins 13, 14, 15 by intermittent operation of the vacuum chuck 17, and finally the semiconductor wafer is placed on the alignment table. It is in a state where it is brought into contact with the position of the reference pin.

Through such operations, the semiconductor wafer can be easily and accurately aligned.

〔Effect of the invention〕

As described in detail above, the present invention is a simple device that can easily align a wafer having a notch, which is highly effective.

[Brief explanation of drawings]

FIG. 1 is a perspective view for explaining the alignment of the plate-shaped body of the present invention, FIG. 2 is a schematic plan view of aligning the OF part of the semiconductor wafer with the reference plate, and FIG. 3 is a cross-sectional view of the air nozzle. Figure 4 is a cross-sectional view of the vacuum chuck, Figures 5a to 5f are schematic cross-sectional views for explaining the functions of the present invention, and Figure 6 is the conventional positioning of the OF of a semiconductor wafer and the reference pin. It is a perspective view showing a mechanism for this. In the figure, 3 is a semiconductor wafer, 11 is an alignment plate, 12 is a guide, 13, 14, 15 are reference pins, 16 is an air nozzle hole, 17 is a vacuum chuck, 18 is a rotor, 19 is a reference plate, 20 is a frame, 21 is a mechanism that can be raised and lowered, and 22 is an OF detection device.

Claims (1)

[Claims] 1. On an inclined alignment table equipped with an air nozzle, a vacuum chuck, a rotor, a reference plate, and a reference pin, a wafer having a notch on one side is levitated by the air nozzle and transferred to the rotor, and the plate-like After the body is rotated by the rotor so that the notch matches the reference plate, the rotor and the reference plate are once removed, and the plate-like body, which is suspended by the vacuum chuck, is placed on the alignment table. A method for aligning a wafer, characterized in that the wafer is moved slowly by intermittently performing vacuum suction and vacuum releasing operations, and the wafer is placed at the position of the reference pin.