JPH04154146A - Positioning device of circular plate body - Google Patents

Abstract

PURPOSE:To enable a circular plate body to be positioned positively by allowing an outer-periphery part of the circular plate body to be detected with a light- receiving sensor when rotating the circular plate body on a rotary table and allowing the center of the circular plate body to fall on a rotary center of the rotary table based on an amount of eccentricity and a rotary position of the table. CONSTITUTION:A wafer within a wafer cassette 5 is taken out through a loading arm 6a of a take-out device 6, is placed on a rail 9, is placed on a traveling table 10 which is shifted to the wafer take-out position, and is sucked and fixed. The wafer 2 is transported to a rotary table position, a table 15 is lifted, and a rotary body 17 is projected from a space between arms 12 of the table 10 and lifts up the wafer 2. A rotary body 17 allows the wafer 2 to be rotated, a light-receiving line sensor 22 receives light from a light source 18 and detects an outer-periphery part of the wafer 2, and then stores a rotary angle of the rotary body 17 and an amount of eccentricity of the wafer 2 into a counter electric circuit 25. The table 15 is lowered, the wafer 2 is placed on the table 10, and by moving the table 10, the center of the wafer 2 is made to fall on the rotary center of the table 15.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is useful for positioning a wafer at a predetermined position in an analysis device, for example, when performing material analysis of a wafer used in a semiconductor integrated circuit. The present invention relates to a positioning device for a disc body.

(Prior art) With the recent development of computers, analyzers that analyze wafer materials are often directly connected to wafer production lines, and as a result, it has become necessary to keep wafers clean, especially those that do not allow dust or dirt. The reality is that devices are being developed one after another to automatically set wafer samples in analyzers so that they can be measured.

Generally, the material analysis of wafers requires measuring the same location on each wafer, and the wafers must be positioned and set at a predetermined position in an analysis device.

As a conventional wafer positioning device, one shown in FIG. 7 is known. That is, the device includes a mounting table 53 on which one wafer 50 taken out from a wafer cassette 51 in which a plurality of wafers 50 are stored is mounted.
, a stopper 54 provided on the mounting table 53 , and a movable body 57 movable in the radial direction of the wafer 50 via a cylinder 55 .

By moving the movable body 57 and bringing the wafer 50 into contact with the stopper 54, the wafer 50 is positioned at its center or at a predetermined position on the mounting table 53.

(Problem to be Solved by the Invention) However, in the conventional positioning device, when positioning the wafer 50, the outer peripheral edge of the wafer comes into contact with the stopper 54 and the movable body 57. However, there is a risk that chips from the wafer 50 will be generated, which is undesirable for the wafer 50 where dust cannot be tolerated, and furthermore, there is a drawback that the center position of the wafer 50 may be shifted.

Also, when the wafer 50 and the stopper 54 etc. come into contact,
There was also the possibility that contact noise would be generated and become a source of noise.

In view of the above problems, the present invention makes it possible to position a disc body such as a wafer at a predetermined position without the outer peripheral edge of the disc body coming into contact with a stopper or the like, thereby cutting the disc body. It is an object of the present invention to provide a positioning device for a disc body that can prevent the generation of powder, can reliably position a disc body at a predetermined position, and is free from noise.

(Means for solving one problem) The present invention was made in order to solve the above problem,
Its features are a disc body positioning device for positioning a disc body 2 such as a wafer at a predetermined position, and includes a rotary table 15 for rotating the disc body 2, and one side of the disc body 2. a light source 18 disposed on the side and in the radial direction of the disc body 2; and a light source 18 disposed on the disc body 2 in the radial direction of the disc body 2; A light receiving sensor 22 provided on the other side of the rotary table 15 and an eccentricity amount for storing the rotation angle of the rotary table 15 and the eccentricity of the disc body 2 corresponding to the rotation angle and obtained by the signal from the light receiving sensor 22. a counting means 25; a moving table 10 for moving the disk body 2 in the radial direction with respect to the rotary table 15; and a center 01 of the disk body 2 by moving the disk body 2 with the moving table 10. The disk body 2 is stored in the eccentricity counting means 25 so that the rotation center 0 of the rotary table 15 coincides with
A control device 2 that reads the rotation angle of the disk body 2 corresponding to the maximum eccentricity β of and controls the rotation of the rotary table 15.
8 will be provided.

Further, a notch 3 is formed in the disc body 2, and a calculation process is performed to correct the eccentricity of the notch 3 portion of the disc body 2 to the eccentricity of the disc body 2 without the notch 3. A device 27 is provided, and the center 01 of the disc body 2 is set on the rotary table 15 based on the eccentricity calculated and corrected by the calculation processing device 27.
The rotation angle of the notch 3 portion stored by the eccentricity counting means 25 is adjusted so that the notch 3 of the disc body 2 is located at a predetermined position in the circumferential direction of the disc body 2. It is also possible to configure the rotary table 15 to be rotationally controlled by reading the .

Furthermore, it is preferable that the light receiving sensor 22 be constructed from a solid-state image sensor.

(Function) In the disc body positioning device configured as described above,
When the disc body 2 placed on the rotary table 15 rotates, the light receiving sensor 22 receives light from the light source 18, the outer peripheral edge of the disc body 2 is detected, and the light is determined by the signal of the light receiving sensor 22. The eccentricity of the disc body 2 and the rotation angle of the rotary table 15 are stored in the eccentricity counting means 25.

The control device 28 reads the maximum eccentricity l stored in the eccentricity counting means 25 and the rotation angle of the rotary table 15 at that time, and controls the rotation of the rotary table 15 to a predetermined rotation angle. After the rotation of the rotary table 15 is controlled, the moving table 10 moves the disc body 2 to align the center 01 of the disc body 2 with the rotation center O of the rotary table 15.

In addition, if an arithmetic processing unit 27 is provided, the arithmetic processing unit 27 calculates and corrects the eccentricity of the notch 3 portion of the disc body 2 to the eccentricity when there is no notch 3, and The center of rotation 01 of the disc body 2 is determined based on the eccentricity corrected by calculation.
can be made to coincide with the rotation center 0 of the rotary table 15.

Then, the control means reads the rotation angle of the notch 3 stored in the eccentricity counting means 25, and rotates the rotary table 15 so that the notch 3 is located at a predetermined position in the circumferential direction of the disc body. It is possible to rotate the disk body 2 by a predetermined angle with respect to the cutout 3 portion as a reference.

(Example) Embodiments of the present invention will be described with reference to the drawings.

1 to 6 show examples in which the present invention is applied to an analysis device 1 for analyzing the material of a wafer 2 as a disc body,
The analyzer 1 includes a wafer cassette 5 in which a plurality of wafers 2 are stored in a manner that can be taken out and taken out, and a wafer cassette 5.
A wafer take-out device 6 capable of taking out a single wafer 2 from a wafer 2; a positioning device 7 for positioning the wafer 2 at a predetermined position; It is composed of an analysis section 8 that analyzes the material by irradiating measurement light and measuring the wavelength reflected at that time. Note that similar cutouts 3 are formed in each wafer 2 so that the orientation thereof can be seen.

The positioning device 7 moves the wafer take-out device 6 and the analysis section 8 along a rail 9 laid horizontally on the machine stand 1a.
The table 10 is provided with a movable table 10 that can freely move back and forth between the table body 1 and stop at a predetermined position.
1 and a pair of 7-arm portions 12 extending from the main body 11 in a direction opposite to the wafer cassette 5 at a distance from each other.

The movable table 10 is provided on its upper surface so that the wafer 2 can be fixed thereon by suction.

Reference numeral 15 denotes a rotary table for rotating the wafer 2 transferred by the moving table 10, and is provided between the wafer cassette 5 and the measurement light irradiation section 12 of the analysis section 8. The rotary table 15 is provided to be movable up and down with respect to the movable table 10, and includes a table body 16 having a built-in driving means such as a stepping motor, and a rotatable disk body located above the table body 16. It consists of 17.

The disk rotating body 17 can move up and down between 7 and 12 of the movable table 1o, and when raised, it moves up and down the upper surface of the movable table 10 so that the wafer 2 placed on the movable table 1o can be separated from the movable table 1o. (See Figure 3 for more prominent)
, is located below the arm portion 12 to allow movement of the moving table 1o when descending (see Fig. 2).
. Further, the disc rotating body 17 is provided on its upper surface so that the wafer 2 can be fixed thereon by suction.

Reference numeral 18 denotes a plurality of light sources located above the wafer 2 and arranged in a straight line in the radial direction.
- provided in the frame 21.

22 is a plurality of CCDs arranged in the same direction as the light source 18;
The light-receiving line sensor is composed of a type solid-state image pickup device or the like, and the above-mentioned attachment is provided on the lower part 23 of the body 20 located below the wafer 2. The light receiving line sensor 22 is connected to the light source 1.
The position of the outer peripheral edge of the wafer 2 can be detected by receiving the light from the wafer 8.

The light receiving line sensor 22 is connected to an eccentricity counting electronic circuit (eccentricity counting means) 25, and when the wafer 2 is rotated on the disk rotating body 17, the eccentricity counting electronic circuit 25 The rotation angle of the plate rotating body 17 and the eccentricity of the wafer 2 corresponding to the rotation angle and obtained from the signal from the light receiving line sensor 22 (the eccentricity of the wafer 2 with respect to the rotation center 0 of the disc rotating body 17) are stored. It is something to keep.

27 is an arithmetic processing unit that reads the rotation angle of the disc body stored in the eccentricity counting electronic circuit 25 and the eccentricity of the disc body with respect to the rotation angle, and cuts out the measured eccentricity in the disc body. This is to correct the calculation to the correct eccentricity amount (hereinafter referred to as corrected eccentricity amount) in the case where there is not 3.

Reference numeral 28 denotes a control device, and the control device 28 reads the maximum eccentricity l of the corrected eccentricity calculated and corrected by the arithmetic processing device 27 and the rotation angle of the disk rotating body 17 at that time, and controls the wafer 2. By moving the moving table 1o, the rotation of the rotating disc 17 is controlled and moved based on the read rotation angle so that the center 01 of the wafer 2 coincides with the rotation center 0 of the rotating disc 17. The table 10 is moved by a distance corresponding to the maximum eccentricity l of the wafer 2.

Further, the wafer 2 is placed between its center 01 and the disk rotating body 17.
When the wafer 2 is rotated in a state where it coincides with the rotation center O, the eccentricity counting electronic circuit 25 stores the rotation angle of the disk rotating body 17 in which the 3 notches of the wafer 2 are located. and,
The control device 28 is a disc rotating body 1 having three notches.
7 is read, the direction in which the notch 3 is located is set as a reference T1, and the rotary table 15 is rotated at a predetermined angle relative to the reference so that the notch 3 is located at a predetermined position in the circumferential direction of the wafer. do.

Next, a case will be described in which material analysis of the wafer 2 is performed using the above-mentioned apparatus.

First, the wafer 2 in the wafer cassette 5 is taken out via the loading 7-me 6a of the wafer take-out device 6, and placed above the rail 9! let

At this time, the moving table 10 has been moved toward the wafer take-out device 6, and the wafer 2 is placed on the moving table 10 and fixed by suction.

Next, when the wafer 2 is transferred to the position of the rotary table 15 by the movable table 10, the rotary table 15 is raised, and the disk rotating body 17 is transferred to the arm 1 of the movable table 10.
The wafer 2 is suddenly lifted up from between the two (see FIG. 3). After that, the wafer 2 is rotated by the disk rotating body 17, or when the wafer 2 is rotated, the light receiving line sensor 22 receives the light from the light source 18.
The outer peripheral edge of the wafer 2 is detected, and the rotation angle of the disk rotating body 17 and the eccentricity of the wafer 2 relative to the rotation angle are sequentially stored in the eccentricity counting electronic circuit 25.

After the wafer 2 has been rotated one or more revolutions, the arithmetic processing unit 25 reads the rotation angle of the wafer 2 and the amount of eccentricity with respect to the rotation angle (see FIG. 4).

The amount of eccentricity of the wafer 2 becomes smaller at the cutout portion 3, as shown in the figure.

Next, for a certain rotation angle of the disk rotating body 17 stored in the eccentricity counting electronic circuit 25 and the rotation angle, 180
° Add the phase-shifted eccentricity and divide by 2 to find the average value,
This average value is compared with a lower reference value calculated and set in advance for the case without the notch 3. In this case, the two parts are the part with the notch 3 and the part with a phase shift of 1800 degrees.
There are some areas that deviate from below the standard value (see Figure 4).

Furthermore, by doubling one deviation amount a (see Figure 4) and adding that deviation amount a to the already measured eccentricity, the corrected eccentricity in the case without a notch can be obtained (see Figure 4). (See mouth).

In addition, if the other deviation amount a is doubled (see Figure 4), the eccentricity of the part without the notch 3 is multiplied by the deviation amount 2.
When a is added, the eccentricity does not become the correct corrected eccentricity, as shown in FIG.

To determine whether or not the amount of eccentricity is corrected, measure whether there are three or more peaks or valleys in the trajectory of the amount of eccentricity per one rotation of the wafer, and if there are three or more, , other deviation amounts are doubled and added to the eccentricity amount at the same rotation angle.

Next, based on the corrected eccentricity shown in FIG. 4A, the maximum eccentricity 1 and the rotation angle of the disc rotating body 17 at that time are determined.

Then, as shown in FIG. 5, the direction B in which the wafer 2 is moved is
is parallel to the moving direction A of the moving table 10,
The rotation of the rotary table 15 on which the wafer 2 is placed is controlled based on the obtained rotation angle. rotary table 1
After the rotation control in step 5, the rotary table 15 is lowered and the wafer 2 is placed on the moving table 10.

After that, the moving table 10 is moved by a distance corresponding to the maximum eccentricity l of the wafer 2, and the center 01 of the wafer 2 is moved.
The center of rotation 0 of the rotary table 15 can be precisely aligned with the rotation center 0 of the rotary table 15.

After aligning the center 01 of the wafer 2 with the rotation center 0 of the rotary table 15 in this way, the wafer 2 is moved a predetermined distance toward the analysis section 8 by the moving table 10, and the center of the wafer 2 is irradiated with far infrared rays. The material is then analyzed.

After the analysis of the center 01 of the wafer 2 is completed, if you wish to further measure a location other than the center 01 of the wafer 2, move the moving table 10 back a predetermined distance to the rotary table 15 again, and move the wafer 2 through the rotary table 15. While rotating, the position of the outer peripheral edge of the wafer 2 is measured using the light source 18 and the light receiving line sensor 22.

At this time, since the center 01 of the wafer 2 and the rotation center 0 of the disk rotating body 17 coincide, the wafer 2 does not become eccentric, and only the notch 3 portion is shifted as described above.

The rotation angle of the disc rotating body 17 at the start of this shift and the rotation angle at the end are divided and compared, and the ratio T1 is set as the center of the two angles or the direction where the notch is located, and the notch is The wafer 2 is rotated by a predetermined angle α with respect to the reference T1 so that the wafer 2 is located at a predetermined position in the circumferential direction of the wafer 2.

After the wafer 2 is indexed to the predetermined angle α position in this way, the wafer 2 is moved to the analysis section 8 again, and the predetermined position P
(See Figure 6). Note that the measurement location on the wafer 2 can be arbitrarily set by determining the rotation angle of the wafer 2 as appropriate.

After measuring the wafer 2, the wafer 2 is transferred to the wafer take-out device 6, the measured wafer 2 is stored in the wafer cassette 5, and the next wafer 2 to be measured is taken out and the same analysis is performed. It is.

In the above embodiment, the notch 3 is provided at one location on the wafer 2. However, the notch 3 is not limited to one location, but may be provided in a plurality of locations. Even if the wafer 2 (disk body) is a disk body other than the wafer 2 without the wafer 2, it is possible to position the wafer 2 (disk body) in the same way. Note that when measuring a disc body without the notch 3, it is not necessary to correct the eccentricity of the disc body to the correct corrected eccentricity as described above.

Further, the means for aligning the center of the wafer with the center of rotation of the rotating disk body and the means for indexing the wafer to a predetermined rotational position are not limited to those of the above embodiments, and may be freely changed in design. .

(Effects of the Invention) Since the present invention is configured as described above, unlike the conventional art, the center of the wafer can be positioned at a predetermined position without the outer peripheral edge of the wafer coming into contact with a stopper or the like. .

As a result, it is possible to prevent wafer chips from being generated when positioning the center of the wafer, and the wafer can be reliably positioned at a predetermined position without shifting the center of the wafer due to the generation of chips. becomes.

Moreover, since the wafer does not come into contact with a stopper or the like during positioning, the contact noise generated at that time is completely eliminated and does not become a source of noise, and its practical value is great.

Further, a processing unit is provided which calculates and corrects the eccentricity of the notch part of the disc body to the eccentricity of the disc body without the notch, and reads the rotation angle of the notch part to control the rotary table. When configured to control rotation, it becomes possible not only to position the center of the wafer, but also to accurately determine the state in which the wafer is rotated by a predetermined angle using the notch as a base. It is ideal for wafer material analysis equipment that measures predetermined locations on wafers.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view of the present invention, FIG. 2 is a cross-sectional view showing the rotary table in a lowered state, and FIG. 3 is a cross-sectional view showing the rotary table in an elevated state. FIG. 4 shows an explanatory diagram for calculating and correcting the amount of eccentricity of a wafer having a notch, (a) is a diagram showing the measured amount of eccentricity, and (b) is a diagram showing a certain rotation angle and the 180 degrees from the rotation angle.
Diagram showing the average value of the eccentricity of the degree 1 with a phase shift, (c)
(d) is a diagram showing the deviation of one side of the eccentricity of the notch part.
(e) is a diagram showing the deviation of the other eccentricity of the notch portion; (f) is a diagram showing the incorrectly corrected eccentricity. FIG. 5 is an explanatory diagram when the center of the disk body is aligned with the rotation center of the rotary table, and FIG. 6 is a diagram showing a state in which the wafer is rotated by a predetermined angle. FIG. 7 is a perspective view showing a conventional example.

Claims (1)

[Scope of Claims] 1. A disc body positioning device for positioning a disc body 2 such as a wafer at a predetermined position, which comprises: a rotary table 15 for rotating the disc body 2; and a rotary table 15 for rotating the disc body 2; A light source 18 is arranged on one side of the disc body 2 and in the radial direction of the disc body 2, and a light source 18 is provided to detect the outer peripheral edge position of the disc body 2 by receiving light from the light source 18 when the disc body 2 rotates. The light receiving sensor 22 provided on the other side of the disc body 2, the rotation angle of the rotary table 15, and the eccentricity of the disc body 2 corresponding to the rotation angle and obtained from the signal from the light receiving sensor 22 are stored. a moving table 10 for moving the disc body 2 in the radial direction with respect to the rotary table 15; The rotation angle of the disc body 2 corresponding to the maximum eccentricity l of the disc body 2 stored in the eccentricity counting means 25 is read so that the center 01 of the disc body 2 coincides with the rotation center O of the rotary table 15,
A disc body positioning device characterized in that a control device 28 for rotationally controlling the rotary table 15 is provided. 2 A notch 3 is formed in the disc body 2, and an arithmetic processing device that calculates and corrects the eccentricity of the notch 3 portion of the disc body 2 to the eccentricity of the disc body 2 without the notch 3. 27 is provided, and the center 01 of the disc body 2 is aligned with the rotation center O of the rotary table 15 based on the eccentricity calculated and corrected by the arithmetic processing unit 27, so that the notch 3 of the disc body 2 is circular. It is configured to control the rotation of the rotary table 15 by reading the rotation angle of the three notches stored by the eccentricity counting means 25 so that the rotary table 15 is positioned at a predetermined position in the circumferential direction of the plate. The disk body positioning device according to claim 1, characterized in that: 3. The disk body positioning device according to claim 1 or 2, wherein the light receiving sensor 22 is composed of a solid-state image sensor.