KR20100026743A - Wafer center detecting device and method - Google Patents

Abstract

The present invention detects and corrects the center of a wafer or a wafer including a notch, which is not an exact circle, and is then transferred into the process chamber. The wafer transfer unit, the first starting point, the second starting point, the first end point, and the second end point are detected. Calculates the moving distance of the wafer detection unit and the wafer transfer unit, and calculates the X and Y coordinates of the start and end points of each wafer, and the first and second start points, the second start point and the first end point, and the first end point and Average point of each X coordinate of the remaining three points except for one point having a large deviation among the points where the vertical line formed at the center of each line connecting the second end point and the second end point and the first start point intersects, and respectively Let the average point of the Y coordinate of be the center of the wafer.

According to the present invention, a wafer center detecting apparatus and method for detecting and correcting the center of a wafer and then transferring the wafer to a predetermined position in the process chamber even if the wafer, which is not an exact circular shape or an error in the wafer diameter, is transferred for the process. Can be provided.

Description

Apparatus for Detecting Wafer Center and Method

The present invention relates to an apparatus for detecting a center of a wafer and a method thereof, and more particularly, to an apparatus for detecting a center of a wafer that detects and corrects a center of a wafer or a wafer including a notch, and to be transferred into a process chamber, and a method of detecting the center of a wafer. It is about a method.

Wafers go through various processes to produce semiconductor chips. In the case of the etching process and the deposition process, such as a wafer cassette containing a plurality of wafers, a process chamber for receiving wafers and carrying out a predetermined process, and a robot for transferring wafers taken out of the wafer cassette to a predetermined position in the process chamber. It has a feed drive.

In the transfer drive unit, it is common to carry out centering on the wafer during transfer in order to take out a wafer which is not accurately accommodated and to accurately seat the wafer at a predetermined position in the process chamber.

In the past, the center of a wafer was calculated using the diameter of a pre-input wafer under the assumption that the wafer was an accurate circle. However, in reality, since the wafer is not an exact circle, the diameter is not constant, there is a problem that an error occurs when calculating the center of the wafer in this way.

In addition, in reality, since the length of the wafer diameter is slightly different, when the actual diameter of the wafer is different from the previously input diameter, the method of calculating the center of the wafer according to the method of calculating the center of the wafer by the diameter of the previously input wafer as described above is performed. There was a problem that an error occurs.

It is an object of the present invention to solve the above problems, even if a wafer that is not an exact circular shape or an error in the wafer diameter is transferred for the process, the center of the wafer is detected and corrected and then transferred to a preset position in the process chamber. An apparatus for detecting a center of a wafer and a method thereof are provided.

In order to achieve the above object, the apparatus for detecting the center of a wafer of the present invention and a method thereof include a wafer transfer unit for transferring a wafer, a first start point, a second start point, a first end point, and a second end point of the wafer transferred by the wafer transfer unit. Calculate the moving distance of the pair of wafer sensing unit and the wafer transfer unit to calculate the X and Y coordinates of the start point and the end point of each wafer, and the center and the second start point of the line connecting the first and second start points. A vertical line formed at the center of the segment connecting the first and second end points and the first end point, and a vertical line formed at the center of the line connecting the first and second end points, respectively. The third point and the second end point and the first starting point at which the vertical lines formed at the center of the line connecting the second point, the first end point and the second end point and the center line of the line connecting the second end point and the first starting point intersect, respectively.Is the average point of each X coordinate of the remaining three points except one point having a large deviation among the fourth points where the vertical lines formed at the center of the line segment and the center line of the line connecting the first and second starting points, respectively, Provided is a wafer center detection apparatus including a control unit such that the average point of each Y coordinate is the center of the wafer.

One side of the wafer transfer part is connected to a first joint part and a second joint part having the same length, and is connected to a driving part that drives the wafer transfer part through a motor, and the other side may include a support part on which the wafer is seated.

The moving distance of the wafer transfer part is a linear length from one end of the first joint part to the other end of the second joint part in a state where the other end of the first joint part and the one end of the second joint part are coupled, and the second joint part is connected at one end of the first joint part. The angle between the straight line to the other end and the first joint part or the second joint part and the length of the first joint part or the second joint part may be calculated by applying the trigonometric function.

In the control unit, the size of the angle may be mapped and stored according to the number of motor rotations of the driving unit.

,

,

및

로 산출(여기서, b는 제1관절부 또는 제2관절부의 길이, θ₁은 웨이퍼의 제1시작점이 감지되었을 때의 모터 회전 수에 맵핑 된 사이각, θ₂는 웨이퍼의 제2시작점이 감지되었을 때의 모터 회전 수에 맵핑 된 사이각, θ₃은 웨이퍼의 제1끝점이 감지되었을 때의 모터 회전 수에 맵핑 된 사이각, θ₄는 웨이퍼의 제2끝점이 감지되었을 때의 모터 회전 수에 맵핑 된 사이각)될 수 있다.The length of each straight line from one end of the first joint to the other end of the second joint when a first start point, a second start point, a first end point and a second end point of the wafer are detected a ₁ , a ₂ , a ₃ And a ₄ are each

,

,

And

(Where b is the length of the first joint or the second joint, θ ₁ is the angle between the motor revolutions when the first starting point of the wafer is detected, and θ ₂ is the second starting point of the wafer). The angle θ ₃ mapped to the motor rotational speed when θ ₃ is the angular angle mapped to the motor rotational speed when the first endpoint of the wafer is detected, and θ ₄ is the motor rotational speed when the second endpoint of the wafer is detected. Mapped angles).

The wafer detector may be an optical sensor or a laser sensor.

In addition, the apparatus for detecting the center of a wafer of the present invention and a method thereof for achieving the above object include a first start point, a second start point, In the second and second steps of detecting the first and second endpoints by the wafer detection unit, when the starting point and the end point of the wafer are detected in the second step, the control unit calculates the moving distance of the wafer transfer unit to determine the first starting point, the second starting point, and the second end point. If the X and Y coordinates of the starting point and the end point of the wafer are calculated in the third and third steps of calculating the X and Y coordinates of the first and second endpoints, the segment connecting the first and second starting points. The first point where the vertical line formed at the center of the line connecting the center and the second start point and the first end point of the intersection of the first point, the center of the line connecting the second start point and the first end point, and the line segment connecting the first end point and the second end point, respectively. Number formed in the center The second point where the line intersects, the third point and the second end point and the first point at which the vertical line formed at the center of the line connecting the first end point and the second end point and the vertical line formed at the center of the line segment connecting the second end point and the first starting point, respectively, intersect. The average of each X coordinate of the other three points except for the one with high deviation among the fourth points where the vertical lines formed at the center of the line connecting the starting point and the vertical line formed at the center of the first connecting point and the second starting point respectively cross each other. A method of detecting a center of a wafer is provided, comprising a fourth step of detecting a point and an average point of each Y coordinate as the center of the wafer.

In the third step, the movement distance of the wafer transfer part may include an angle between a straight line from one end of the first joint part connected to one side of the wafer transfer part to the other end of the second joint part and the first joint part or the second joint part or the first joint part or It can be calculated by applying the length of the second joint portion to the trigonometric function.

In the third step, the size of the angle may be pre-mapped and stored in the controller according to the number of motor rotations of the driving unit driving the wafer transfer unit.

,

,

및

로 산출(여기서, b는 제1관절부 또는 제2관절부의 길이, θ₁은 웨이퍼의 제1시작점이 감지되었을 때의 모터 회전 수에 맵핑 된 사이각, θ₂는 웨이퍼의 제2시작점이 감지되었을 때의 모터 회전 수에 맵핑 된 사이각, θ₃은 웨이퍼의 제1끝점이 감지되었을 때의 모터 회전 수에 맵핑 된 사이각, θ₄는 웨이퍼의 제2끝점이 감지되었을 때의 모터 회전 수에 맵핑 된 사이각)될 수 있다.In a third step, the respective linear lengths a ₁ , a ₂ , from _one end of the first joint portion to the other end of the second joint portion when the first start point, the second start point, the first end point and the second end point of the wafer are detected. a ₃ And a ₄ are each

,

,

And

(Where b is the length of the first joint or the second joint, θ ₁ is the angle between the motor revolutions when the first starting point of the wafer is detected, and θ ₂ is the second starting point of the wafer). The angle θ ₃ mapped to the motor rotational speed when θ ₃ is the angular angle mapped to the motor rotational speed when the first endpoint of the wafer is detected, and θ ₄ is the motor rotational speed when the second endpoint of the wafer is detected. Mapped angles).

As described above, according to the present invention, even if a wafer, which is not an exact circular shape or an error in the wafer diameter, is transferred for the process, the center of the wafer is detected so that the center of the wafer is detected and corrected and then transferred to a preset position in the process chamber. It is possible to provide an apparatus and a method thereof.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

1 is a perspective view showing a center detection apparatus of a wafer according to an embodiment of the present invention, Figure 2 is a plan view showing a wafer transfer unit and a wafer detection unit according to an embodiment of the present invention.

As shown in FIGS. 1 and 2, a center detection apparatus for a wafer according to an embodiment of the present invention includes a load lock chamber 100, a transfer chamber 300, and a process chamber; 400 and a wafer transfer part 500.

The load lock chamber 100 includes a wafer 600 in which a plurality of wafers 600 on which a predetermined semiconductor device fabrication process is performed is loaded in a wafer cassette (not shown), or in which a predetermined process is completed in the process chamber 400. Is accommodated in a wafer cassette.

A cassette door (not shown) is formed at one side of the load lock chamber 100, and a wafer cassette in which the wafer 600 is accommodated is loaded or unloaded through the cassette door.

In addition, when the wafer cassette in which the wafer 600 is accommodated is loaded, the load lock chamber 100 is in a low vacuum state by a low vacuum pump (not shown).

The process chamber 400 is a process of manufacturing a semiconductor device, such as a dry etching process, chemical vapor deposition process. The process chamber 400 is a process of manufacturing a semiconductor device in a state where high vacuum is formed by the operation of a high vacuum pump.

In addition, in the process chamber 400, the wafer 600 should be seated at the correct position in order to proceed with a predetermined process.

The transfer chamber 300 connects the process chamber 400 and the load lock chamber 100 and provides a buffer space. In general, a plurality of process chambers 400 may be connected to the transfer chamber 300.

In addition, a low vacuum pump for controlling an internal pressure of the transfer chamber 300 is connected to one side of the transfer chamber 300, and a flat zone is formed in the wafer 600 injected into the transfer chamber 300. An alignment process of aligning in one direction based on the reference is performed.

In addition, a wafer transfer unit 500 for transferring the wafer 600 is provided at the inner center of the transfer chamber 300.

The wafer transfer unit 500 may remove the wafer 600 from the load lock chamber 100 and transfer the wafer 600 to the process chamber 400, or transfer the wafer 600 from the process chamber 400 to the load lock chamber 100. The robot arm 510 is provided.

One side of the robot arm 510 is connected to a first joint 511 and a second joint 513 having the same length, and are connected to a driving unit 550 for driving the wafer transfer unit 500 such as rotation or lifting. The other side of the 510 is provided with a support 515 for supporting the wafer 600 to be seated.

Meanwhile, a wafer entrance 200 for transferring the wafer 600 is formed between the load lock chamber 100 and the transfer chamber 300, and the wafer 600 is also provided between the transfer chamber 300 and the process chamber 400. Each door is provided for transport.

Therefore, when the wafer cassette on which the plurality of wafers 600 are loaded is introduced into the load lock chamber 100 through the cassette door, the low vacuum pump is operated to maintain the internal pressure of the load lock chamber 100 in a low vacuum state. Is formed.

 The wafer 600 loaded in the wafer cassette is moved into the transfer chamber 300 in which the low vacuum state is formed while being seated on the wafer transfer part 500.

Then, the wafer 600 in the transfer chamber 300 is moved into the process chamber 400 in which the high vacuum state is formed by the operation of the high vacuum pump.

Subsequently, the wafer 600 inside the process chamber 400 is loaded into the wafer cassette of the load lock chamber 100 via the transfer chamber 300 by the wafer transfer unit 600 in the reverse order of the operation described above. do.

The transfer chamber 300 includes a slot (not shown) through which the wafer transfer unit 500 enters and exits, and the slot includes a first wafer detector unit for detecting a center position of the wafer 600 seated on the wafer transfer unit 500. 710 and a second wafer detector 720 are provided.

The pair of wafer detectors 710 and 720 are spaced apart at predetermined intervals, and have an optical sensor having a transmitter (not shown) and a receiver (not shown), respectively, in a direction perpendicular to the top surface of the wafer 600. In addition, it is possible to use a variety of known sensors, such as a laser sensor using the amount of reflection of light.

In addition, a control unit (not shown) for controlling a semiconductor manufacturing process, such as the transfer of the wafer 600 between the load lock chamber 100, the transfer chamber 300, and the process chamber 400, and the process within the process chamber 400, is provided. It is provided.

The controller may include a transceiver (not shown) for transmitting a signal, a computing device (not shown) for calculating a predetermined value using a predetermined algorithm, equation, or the like based on various data, signals, and the like, and a wafer. The direction and position of the transfer unit 500 may be controlled.

3 is a flow chart showing a wafer center detection method according to an embodiment of the present invention, Figure 4 is a plan view showing a state of detecting a first starting point of the wafer according to an embodiment of the present invention, Figure 5 is a view of the present invention 6 is a plan view illustrating a state of detecting a second starting point of a wafer according to an embodiment, FIG. 6 is a plan view illustrating a state of detecting a first end point of a wafer according to an embodiment of the present invention, and FIG. 7 illustrates an embodiment of the present invention. 8 is a plan view illustrating a state in which a second end point of a wafer is sensed according to an example, and FIG. 8 is a plan view illustrating a state in which a center of a wafer is designated according to an embodiment of the present invention.

First, while the wafer detectors 710 and 720 are fixed to the slots of the transfer chamber 300, the controller drives the driver 550 so that the wafer transfer unit 500 drives the wafer 600 to the load lock chamber 100. To be taken out to be transferred to the process chamber 400 (step S110).

In the present invention, the wafer 600 may be a wafer that is not an accurate circle by having a curvature on an accurate circle or an outer circumferential surface, and the outer circumferential surface may include a notch. Therefore, the diameter of the wafer 600 may vary depending on the position of the outer circumferential surface of the wafer 600.

As the wafer transfer unit 500 moves forward, the wafer detectors 710 and 720 irradiate light toward an edge of the wafer 600 preset in a direction perpendicular to the upper surface of the wafer 600. As shown in FIG. 4 and FIG. 5, since the wafer 600 has a curvature on the outer circumferential surface, the wafer 600 is not an accurate circular shape, and thus the first starting point R1 is first detected by the first wafer detection unit 710. In operation S120, the second wafer detection unit 720 detects the second starting point R2.

Subsequently, the wafer transfer part 500 is continuously moved forward, and as shown in FIGS. 6 and 7, the first end point R3 including the notch is first detected by the second wafer detection part 720, and the first The second end point R4 is detected by the wafer detector 710 (step S130).

Here, the order of the start point (R1, R2) and the end point (R3, R4) of the wafer 600 detected by the first wafer detector 710 and the second wafer detector 720 is in the form of the wafer 600. Therefore, it may vary.

For example, the wafer detection units 710 and 720 may detect a point including the notch and set the starting point R1 and R2 or the end point R3 and R4.

Thus, according to the shape of the wafer, the first wafer detection unit 710 may first detect the second starting point R2, and the second wafer detection unit 720 may detect the first starting point R1. If the notch is formed toward the first wafer detector 710, the first wafer detector 710 first detects the second end point R4, and the second wafer detector 720 first detects the first end point R4. The end point R3 will be detected.

In the present invention, the first end point R3 is shown to include a notch.

Subsequently, in order to detect the center of the wafer 600, the length between the first start point R1 and the second end point R4 and the length between the second start point R2 and the first end point R3 are calculated ( Step S140).

The length between the start points R1 and R2 and the end points R3 and R4 is determined when the moving distance and the end points R3 and R4 of the robot arm 510 when the start points R1 and R2 are respectively detected. It can be calculated as the difference in the moving distance of the robot arm 510.

For example, if the first wafer detection unit 710 detects the first starting point R1, as shown in FIG. 4, the first joint part 511 and the second joint part 513 of the robot arm 510 are detected. The shape can be represented as an isosceles triangle. Here, the length of the base of the isosceles triangle, which is a straight line length a ₁ between one end of the first joint part 511 and the other end of the second joint part 513, may be calculated using a trigonometric function as shown in Equation 1 below.

Here, b is the length of the first joint 511 or the length of the second joint 513, θ ₁ is an angle mapped to the motor (not shown) rotation speed when the first starting point (R1) is detected.

Then, when the robot arm 510 is moved to detect the second starting point R2 in the second wafer detector 720, as shown in FIG. 5, one end of the first joint portion 511 and the second joint portion 513. The straight line length a ₂ between the other ends of) may be represented by an isosceles triangle.

Similarly, the length of the base of the isosceles triangle can be obtained using a trigonometric function as shown in Equation 2.

Here, b is the length of the first joint 511 or the length of the second joint 513, θ ₂ is the angle mapped to the motor speed when the second starting point (R2) is detected.

If the robot arm 510 is moved to detect the first end point R3 by the second wafer detector 720, one end of the first joint part 511 and the second joint part 513 are shown in FIG. 6. The straight line length a ₃ between the other ends of) may be represented by an isosceles triangle.

Similarly, the length of the base of the isosceles triangle can be obtained using a trigonometric function as shown in Equation 3.

Here, b is the length of the first joint 511 or the length of the second joint 513, θ ₃ is the angle mapped to the motor speed when the first end point (R3) is detected.

Then, when the robot arm 510 is moved to detect the second end point R4 by the first wafer detector 710, as shown in FIG. 7, one end of the first joint part 511 and the second joint part 513. The straight line length a ₄ between the other ends of) may be represented by an isosceles triangle.

Similarly, the length of the base of the isosceles triangle can be obtained using a trigonometric function as shown in Equation 4.

Here, b is the length of the first joint 511 or the length of the second joint 513, θ ₄ is the angle mapped to the motor speed when the second end point (R4) is detected.

θ ₁ , θ ₂ , θ _3, and θ ₄ are angles between a straight line from one end of the first joint 511 to the other end of the second joint 513 and the first joint 511 or the second joint 513. The driver 550 calculates the number of rotations of the motor provided in the driver 550 when the wafer detectors 710 and 720 detect the start points R1 and R2 and the end points R3 and R4, respectively. You can find out.

For reference, the motor is provided with an encoder (not shown) which is a device for speed control and position detection of the motor. When the motor rotates, the rotation speed of the motor is calculated by the encoder as a digital value. Calculating the rotational speed of the motor using the encoder is a technique conventionally used in the art, and a detailed description thereof will be omitted.

Therefore, the magnitudes of θ ₁ , θ ₂ , θ _3, and θ ₄ depend on the motor rotational speed after the angle values for the rotational speed of the motor calculated by the encoder are previously determined and stored in the control unit, as shown in Table 1. You can apply angle values.

Revolutions Angle … … 100   55 ° 200   45 ° … … 500   25 ° 600   15 ° … …

For example, if the rotational speed of the motor is calculated to be 100 times through the encoder from the time when the driving unit 550 starts to move the robot arm 510 until the first starting point R1 is detected, θ ₁ is Table 1 shows 55 degrees.

When the driving unit 550 is driven after the first starting point R1 is detected and the rotation speed of the motor when the second starting point R2 is detected is calculated to be 200 times through the encoder, θ ₂ is determined by Table 1. 45 degrees.

In addition, if the rotation speed of the motor when the driving unit 550 is driven to detect the first end point R3 after the second start point R2 is detected is calculated to be 500 times through the encoder, θ ₃ is determined by Table 1 25 degrees.

Similarly, if the rotation speed of the motor when the second end point R4 is detected by driving the driving unit 550 after the first end point R3 is detected is calculated to be 600 times through the encoder, θ ₄ is determined by Table 1 15 degrees.

Thus, when the difference in the length of the base of the isosceles triangle is calculated using Equations 1, 2, 3, and 4, the length between the first start point R1 and the second end point R4 and the second end point R4 are calculated. The length between the two start points R2 and the first end point R3 can be calculated.

For example, as shown in FIG. 8, subtracting the length a ₁ of the isosceles triangle at the first starting point R1 from the length a ₄ of the isosceles triangle at the second endpoint R4 is subtracted. The length L ₁ between the first start point R1 and the second end point R4 is obtained.

Then, subtracting the length a ₂ of the isosceles triangle at the second starting point R2 from the length a ₃ of the isosceles triangle at the first end point R3, the second starting point R2 and the first The length (L ₂ ) between the end points (R3).

In addition, since the first wafer detector 710 and the second wafer detector 720 are fixed, the length between the first wafer detector 710 and the second wafer detector 720 is predetermined. do.

Thus, X coordinates and Y coordinates of the first starting point R1, the second starting point R2, the first end point R3, and the second end point R4 may be known.

For example, the X coordinate of the first starting point R1 first detected by the first wafer detector 710 is '0', between the first wafer detector 710 and the second wafer detector 720. If the length is represented as 'B', the Y coordinate of the first starting point R1 becomes 'a ₁ ', which is the moving distance of the robot arm 510 when the first starting point R1 is detected.

Subsequently, it can be seen that the X coordinate of the second starting point R2 detected by the second wafer detection unit 720 becomes 'B', and the Y coordinate is the robot when the second starting point R2 is detected. The movement distance of the arm 510 is 'a ₂ '.

Subsequently, it can be seen that the X coordinate of the first end point R3 detected by the second wafer detection unit 720 becomes 'B', and the Y coordinate is the robot when the first end point R3 is detected. The movement distance of the arm 510 is 'a ₃ '.

Similarly, the X coordinate of the second end point R4 that is detected by the first wafer detector 710 for the fourth time may be represented as '0', and the Y coordinate may be represented by the robot arm when the second end point R4 is detected. The moving distance of 510 is 'a ₄ '.

As a result, the coordinate of the first starting point R1 is (0, a ₁ ), the coordinate of the second starting point R2 is (B, a ₂ ), and the coordinate of the first end point R3 is (B, a ₃ ). , The coordinates of the second end point R4 are (0, a ₄ ).

Thus, the linear length between the first starting point R1 and the second starting point R2 may be mathematically calculated using the coordinates of the first starting point R1 and the second starting point R2, which is known in the art. It will be apparent to those skilled in the art.

Similarly, the linear length between the first end point R1 and the second end point R2 may be mathematically calculated using the coordinates of the first end point R3 and the second end point R4.

Accordingly, the length between the first start point R1 and the second start point R2, the length between the second start point R2 and the first end point R3, and between the first end point R3 and the second end point R4. The length of and the length between the second end point R4 and the first start point R1 are calculated.

Subsequently, as shown in FIG. 8, a vertical line is formed at the center of the line connecting the first starting point R1 and the second starting point R2 and the center of the line connecting the second starting point R2 and the first end point R3, respectively. Form the point where the vertical line intersects as the first point (P1)

A vertical line is formed at the center of the line segment connecting the second start point R2 and the first end point R3 and at the center of the line segment connecting the first end point R3 and the second end point R4, respectively. Is defined as the second point P2.

In addition, a vertical line is formed at the center of the line connecting the first end point R3 and the second end point R4 and at the center of the line segment connecting the second end point R4 and the first start point R1, respectively, to cross the vertical line. Is defined as the third point P3.

Similarly, a vertical line is formed at the center of the line connecting the second end point R4 and the first starting point R1 and a vertical line at the center of the line connecting the first starting point R1 and the second starting point R2, respectively. Is defined as the fourth point P4 (step S150).

The first point P1, the second point P2, the third point P3, and the fourth point P4 may be represented by X coordinates and Y coordinates, respectively, and the first point P1 and the second point P2. One of the points P2, the third point P3, and the fourth point P4 having a large deviation due to a notch or the like is excluded without being used to detect the reference center O of the wafer 600.

Accordingly, in the present invention, as shown in FIG. 8, the deviation is greater than the other three points among the first point P1, the second point P2, the third point P3, and the fourth point P4. The second point P2 is excluded to designate the reference center O of the wafer 600.

Thus, as a result, three points of the first point P1, the third point P3, and the fourth point P4 remain, and the average value of each X coordinate of each of the three points and the average value of each Y coordinate are The reference center O, which is the center of the wafer 600, is detected (step S160).

9 is a plan view illustrating a state of correcting a center position of a wafer according to an embodiment of the present invention.

As shown in FIG. 9, when the wafer 600 for processing is transferred to the process chamber 400, the reference center O of the wafer 600 is calculated by the method according to the present invention, and the target center C and Calculate the difference.

If there is no difference between the target center C and the reference center O of the wafer 600, the controller determines that the wafer 600 is correctly loaded and seated on the wafer transfer unit 500, and then proceeds with the process.

However, when it is determined that the position of the wafer 600 is shifted due to the difference between the target center C and the reference center O of the wafer 600, the controller moves the wafer transfer part 500 finely, so that the wafer 600 is moved. Correct the center of reference (O) to be located at the target center (C).

Accordingly, the center detection process and the transfer process of the wafer 600 are completed, and the wafer transfer unit 500 repeats the same process with respect to the next wafer 600.

In the above description, the present invention has been described with reference to preferred embodiments, but the present invention is not necessarily limited thereto, and a person having ordinary skill in the art to which the present invention pertains does not depart from the technical spirit of the present invention. It will be readily appreciated that various substitutions, modifications and variations can be made.

1 is a perspective view showing an apparatus for detecting a center of a wafer according to an embodiment of the present invention;

2 is a plan view showing a wafer transfer unit and a wafer detection unit according to an embodiment of the present invention;

3 is a flow chart showing a wafer center detection method according to an embodiment of the present invention;

4 is a plan view illustrating a state where a first starting point of a wafer is detected according to an embodiment of the present invention;

5 is a plan view illustrating a state where a second starting point of a wafer is detected according to an embodiment of the present invention;

6 is a plan view illustrating a state in which a first endpoint of a wafer is detected according to an embodiment of the present invention;

7 is a plan view illustrating a state where a second end point of a wafer is detected according to an embodiment of the present invention;

8 is a plan view showing a state in which a center of a wafer is designated according to an embodiment of the present invention;

9 is a plan view showing a state of correcting the center position of the wafer according to an embodiment of the present invention.

Claims (10)

A wafer transfer unit for transferring a wafer; A pair of wafer detectors detecting a first start point, a second start point, a first end point, and a second end point of the wafer transferred by the wafer transfer unit; And The moving distance of the wafer transfer unit is calculated to calculate the X and Y coordinates of the start and end points of each wafer, and the center of the line connecting the first start point and the second start point and the center of the line connecting the second start point and the first end point. A first point at which vertical lines respectively formed at the second point intersect, a second point at which a vertical line formed at the center of a line connecting the second starting point and the first end point and a vertical line formed at the center of the line connecting the first end point and the second end point, respectively The center of the line connecting the second end point, the third point where the vertical line formed at the center of the line connecting the second end point and the first starting point intersect, and the center and the first starting point of the line connecting the second end point and the first starting point, The average point of each X coordinate and the average point of each Y coordinate of the remaining three points except for one point having a large deviation among the fourth points where the vertical lines formed at the center of the line connecting the second starting point intersect each other Of A controller for such that the Center detection apparatus of the wafer comprising a. The method of claim 1, One side of the wafer transfer part is connected to a first joint part and a second joint part having the same length, and connected to a driving part for driving the wafer transfer part through a motor, and the other side includes a support part on which the wafer is mounted. Device. The method of claim 2, wherein the moving distance of the wafer transfer unit, In a state in which the other end of the first joint part and the one end of the second joint part are coupled, the straight length from one end of the first joint part to the other end of the second joint part, and the straight line and the second end of the first joint part from the other end of the second joint part. An apparatus for detecting a center of a wafer, which is calculated by applying the angle between the one joint part or the second joint part and the length of the first joint part or the second joint part to the trigonometric function. The method of claim 3, wherein the control unit, The center detection apparatus of the wafer, characterized in that the size of the angle is mapped and stored according to the number of motor rotation of the drive unit. The method of claim 3, The length of each straight line from one end of the first joint to the other end of the second joint when a first start point, a second start point, a first end point and a second end point of the wafer are detected a ₁ , a ₂ , a ₃ And a ₄ are each

,

,

And

Where b is the length of the first or second joint, θ ₁ is the angle between the motor rotations when the first starting point of the wafer is detected, and θ ₂ is the second starting point of the wafer. The angle θ ₃ mapped to the motor rotational speed when θ ₃ is the angular angle mapped to the motor rotational speed when the first endpoint of the wafer is detected, and θ ₄ is the motor rotational speed when the second endpoint of the wafer is detected. Center detection device of the wafer, characterized in that the (mapped angle). The method of claim 1, wherein the wafer detection unit, An apparatus for detecting a center of a wafer, which is an optical sensor or a laser sensor. A first step in which the wafer transfer unit draws and transfers the wafer; A second step of detecting a first starting point, a second starting point, a first end point, and a second end point of the wafer transferred in the first step by the wafer detector; When the start point and the end point of the wafer are sensed in the second step, the control unit calculates the moving distance of the wafer transfer unit to calculate X coordinates and Y coordinates of each of the first start point, the second start point, the first end point, and the second end point. Step 3; And When the X and Y coordinates of the start point and the end point of the wafer are calculated in the third step, the vertical lines formed at the center of the line connecting the first start point and the second start point and the center of the line connecting the second start point and the first end point respectively cross each other. Connecting the first point, the second starting point and the first end point, and the center line of the line connecting the first and second end points, respectively, the second point intersecting the second point, the first end point and the second end point 3rd point where the vertical line formed at the center of the line connecting the center and the second end point and the first starting point intersect, and the line connecting the center of the line connecting the second end point and the first starting point, and the first starting point and the second starting point, respectively. An average point of each X coordinate and an average point of each Y coordinate of the remaining three points are detected as the center of the wafer except for one point having a large deviation among the fourth points where the vertical lines respectively formed at the center of the intersection cross each other. 4th step Center detection method of the wafer comprising a. The method of claim 7, wherein in the third step, The movement distance of the wafer transfer part may be defined as an angle between a straight line from one end of the first joint part connected to one side of the wafer transfer part to the other end of the second joint part and the first joint part or the second joint part, and the length of the first joint part or the second joint part. A center detection method of a wafer, which is calculated by applying to a trigonometric function. The method of claim 8, wherein in the third step, The magnitude of the angle is pre-mapped according to the number of motor rotations of the drive unit for driving the wafer transfer unit is stored in the control unit, characterized in that the wafer. The method of claim 8, wherein in the third step, The length of each straight line a ₁ , a ₂ , a ₃ from one end of the first joint portion to the other end of the second joint portion when the first start point, the second start point, the first end point and the second end point of the wafer are detected. And a ₄ are each

,

,

And

(Where b is the length of the first joint or the second joint, θ ₁ is the angle between the motor revolutions when the first starting point of the wafer is detected, and θ ₂ is the second starting point of the wafer). The angle θ ₃ mapped to the motor rotational speed when θ ₃ is the angular angle mapped to the motor rotational speed when the first endpoint of the wafer is detected, and θ ₄ is the motor rotational speed when the second endpoint of the wafer is detected. Method of detecting the center of the wafer, characterized in that the (mapped angle).

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