JPS6220343A - Wafer positioning device - Google Patents

Abstract

PURPOSE:To detect the periphery of a wafer by other photosensor even if an orifice is directed to one photosensor sensing field by disposing two photosensors even in one detecting direction at wider angle than the angle (approx. 40 deg.) of the orifice. CONSTITUTION:Four photosensors made of light emitting units 7a-10b and photoreceptors 7b-10b are provided around a wafer chuck 2. The four photosensors generate outputs proportional to the area of a wafer in the detecting range (1mmphi) in such a manner that two are disposed at a holding angle of thetas=45 deg. at x-axis as a center and the other two are disposed at a holding angle of thetas=45 deg. at y-axis as a center. The outputs of the photosensors are transmitted to controllers 11, 14 having selectors 12, 15 and servo amplifiers 13, 16. Accordingly, the rotating center of a wafer 1 can be positioned at the prescribed position irrespective of the direction of the orifice without rotating the wafer 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a wafer positioning apparatus, and particularly to a wafer positioning apparatus suitable for a manufacturing apparatus for highly integrated semiconductor integrated circuits.

[Background of the invention]

Semiconductor integrated circuits such as LSIs are fabricated on a disk-shaped substrate called a wafer, which has a cutout (this is called an orientation flat, hereinafter abbreviated as an orientation flat). In semiconductor integrated circuit manufacturing equipment such as wafer exposure equipment (wafer exposure equipment), it is first necessary to position the wafer with reference to its outer circumference.
A device described in Publication No. B2 that mechanically contacts the outer periphery of the wafer (detects the orientation flat 12) and positions the wafer was used.
There is a high possibility that wafer chips or foreign matter will occur, and this is one of the major causes of low yields, especially in highly integrated 18i13 semi-IPJ integrated circuits. On the other hand, Tokukai Akira.

The outer periphery of a wafer as shown in Japanese Patent No. 57-j80141.

5-row wafer positioning device for non-contact positioning.

was devised. According to this device, the wafer outer circumference.

Since the position of the evaporator is optically detected and the evaporator is moved and positioned based on the result, the problem of reduced yield due to the occurrence of foreign matter can be solved. However, with this wafer positioning device, it is necessary to rotate the wafer 5 in order to detect the orientation of the orientation flat, and it takes time to position the wafer.

did. Further, this rotation of the wafer is unavoidable when it is necessary to position the center of the wafer regardless of the orientation of the orientation flat. .

[Objective of the Invention] 10. The object of the present invention is to provide a wafer positioning device that is capable of positioning the wafer at a constant position without rotating the wafer, without contacting the outer periphery of the wafer and regardless of the orientation of the orientation flat. It is about providing.

[Summary of the invention] 15 If the orientation flat is thrown, Uni-No works from two directions.

It is located without contacting the outer periphery by detecting the position.

It is possible to decide. The present invention performs one detection.

Two 7-way sensors (detection means) for each direction.

An angle wider than the angle of the orientation flat (approximately 40°). .

By arranging the two photosensors, even if the orientation flat part faces the field of view of the sensor, the other photosensor can detect the circumferential part of the flat.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described using FIGS. 1 to 6.

This embodiment includes a wafer chuck 2, an Xy stage''6, a transfer arm 6, and photo sensors 7a, b to 10a, b'.
and control circuits 11 and 14. Yo10
To explain in more detail, Unino Chuck 2 is actually capable of vacuum suctioning Unino 1, and
It is fixed on the xy stage 3, and the servo amplifier 1
3.16 and motors 4 and 5, the position in the xy plane can be controlled. Further 1-transport arm 6
can be raised, lowered and swung.

Its tip is capable of vacuum suctioning the wafer 1.

The structure is as follows. On top of that, Unino Chan.

Around the rear 2 are light emitters 7a to 10a and a light receiver.

There are 7 4WA sensors consisting of 7b to 10b.

・ 3 ・ I am. These four photosensors have a detection range ゛(φ1
output proportional to the area of the wafer within am).

is generated, and the angle θ5-45 is centered on the y-axis.
Two pieces at an angle of °, also centered on the y-axis.

The remaining 2@ are placed at an angle of θ5-45°. The output of this photosensor is the selection circuit.

12.15 and a control circuit 11.14 consisting of a servo amplifier 13.16. Next, the operation of this embodiment will be explained. .

First, the wafer 1 is transferred from an external transfer path (not shown) onto the Unino chuck 2 by the transfer arm 6.

and vacuum suction. In this state, servo amplifier 1
3. The target value of I6 is the output value when 50% of the photosensor detection field of view is blocked by the wafer 1.

Then, the control system 11.14 is activated. Selection circuit 121
15 is the light receiver 7b8b1 or 9b, respectively.
10b.

Output the highest output value of 13.16 to the servo amplifier.

introduce. Therefore, the photosensor detects the field of view.

Of course, if the orientation flat is located elsewhere.

As shown in FIG. 2, the photosensor detects the image. .

4. Even if the orientation flat faces one of the fields (8a), the control circuit 14 can move the xy stage 3 and position the wafer 1 at a predetermined position by the output of the other field (7a). In addition, the angle θof of the orientation flat part is about 40°, which is 5 smaller than the angle θ5=45° of the photosensor, and 2
Orifting multiple photosensors at the same time.

It does not detect any hidden parts. (Figure 3) Therefore,
According to this embodiment, the rotation center of the wafer 1 is 0 without rotating the wafer 1 and regardless of the orientation of the orientation flat.
It is possible to position 10 in a fixed position.

Next, another example will be explained using FIG.

I will explain. The present example differs from the above-mentioned example in that ・6 (
vA photosensors 21 to 26 and four selection circuits 28-
The difference is that it includes a control circuit 27 consisting of P-31, two differential amplifiers 32 and 33, and a conversion circuit 1534.

Ru. The operation of this embodiment is as follows: First, the photosensors 22 and 23
．． 25, 26 and selection circuits 28, 30, differential amplifier 3
To 2.

It is tilted 30'' counterclockwise from the y-axis in Figure 3.

The deviation of the wafer 17 in the direction (Ll) is determined. Similarly.

, No. 1 Sen-v21.22, 24.25 and the selection circuit 29゜Lo1, the bias of Unino\17 in the L-su direction is determined on the differential Anzo shoulder.・Second 11. The deviation of the vertical axis in the V2 direction is converted by the conversion circuit 4 into the amount of movement of the xy stage 18 (I7), and the wafer 17 is positioned at a predetermined position.

Furthermore, an example of the doo: :t71S is shown in FIG. 5. In this embodiment, eight
59 to 46 and one feeding control circuit 46.

Its operation is self-evident.
10 In addition, in all of the above-mentioned actual Mu examples, the -1 skin was positioned, and after that, the conveyance system was held at 1-, and during that time, the .

With empty suction, it is possible to place the workpiece on the Uchino chuck without any eccentricity. Furthermore, the 1° control system includes, in addition to the above-mentioned blogging and control control circuits, the microphone "1'7" computer.

This is also possible with a 1t control system that can perform comparative delay processing.

ru.

〔Effect of the invention〕

+-According to the invention, the wafer can be rotated without contacting the outer periphery of the wafer and regardless of the orientation of the orientation flat.
1: ＜Positioning is possible, so there is a loss of 1
This has the effect of suppressing the occurrence of defects and deviations, reducing the yield of integrated circuit elements, and also has the effect of speeding up the positioning time.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the structure of one embodiment of the present invention;
The figure also shows the wafer positioning state. FIG. 3 is a plan view showing another 10 states of wafer positioning, FIG. 4 is a plan view showing another embodiment, and FIG. 5 is a plan view showing another embodiment. This is a +f7- view.

Claims (1)

[Claims] 1. A wafer positioning device comprising a feeding mechanism that can move the wafer in at least two directions, a transport mechanism that loads and transports the wafer, and a mechanism that allows at least one of the wafer chuck and the transport mechanism to move up and down. A detection means for detecting the position of the wafer outer circumference within a certain range without contacting the surface and outer circumference is arranged such that a pair of two detection means in one direction form a predetermined angle with respect to the center of the wafer. and a control system for controlling the feeding mechanism by the output of the detecting means, further provided with pairs of the detecting means in at least two directions so that the total number of detecting means is four or more. A wafer positioning device characterized by being provided with.