KR20210082363A - Apparatus and method for detecting work hole - Google Patents

Abstract

An object of the present invention is to provide a work-hole detection device capable of stably detecting a position of a work-hole of a carrier arranged on a surface plate of a polishing machine. In the work-hole detection device for detecting the position of the work-hole (14) of the carrier (13) disposed on a lower surface plate (12) of the polishing machine (10), the present invention comprises: a laser displacement meter (R) measuring a distance from an object (T); an edge detection unit (33) using the measurement value of the laser displacement meter (R) to detect the position of an edge unit of at least three work-holes (14); and a center calculation unit (34) calculating the center position of the work-hole (14) based on the position of at least three work-holes detected by the edge detection unit (33).

Description

Work hole detection device and work hole detection method {APPARATUS AND METHOD FOR DETECTING WORK HOLE}

The present invention relates to a work-hole detecting apparatus and a work-hole detecting method for detecting the position of a work hole in a carrier holding a wafer to be polished by a polishing machine.

DESCRIPTION OF RELATED ART Conventionally, when grinding|polishing a wafer with a grinder, the work hole detection apparatus which detects the position of the work hole of the carrier which holds a wafer is known (for example, refer patent document 1). In the conventional work hole detection apparatus, image data is acquired by two cameras installed so that a predetermined|prescribed central angle may be achieved. And the center position of a work hole is detected based on the center angle between the position of two points on the edge part of a work hole obtained from this image data, and a camera.

[Patent Document 1] Japanese Patent No. 4492155

However, in the case of using image data when detecting the center position of the work hole, it is considered that the quality of the image data fluctuates due to the influence of the illumination state around the carrier, and therefore the edge portion of the work hole cannot be properly detected. In addition, since image data is used, when the color of the carrier and the polishing surface (polishing pad, etc.) of the surface on which the carrier is arranged are similar, a problem arises that it is difficult to detect the edge portion of the work hole.

The present invention has been made in view of the above problem, and an object of the present invention is to provide a work-hole detecting apparatus and a work-hole detecting method capable of stably detecting a work-hole position of a carrier arranged on a surface plate of a polishing machine.

In order to achieve the above object, the present invention is a workhole detection apparatus for detecting the position of a workhole of a carrier disposed on a surface plate of a polishing machine, a distance measuring unit for measuring the distance to an object, and the measured value of the distance measuring unit An edge detection unit for detecting the position of the edge portion of the work hole at three or more locations using the edge detection unit, and a center calculating unit for calculating the center position of the work hole based on the position of the edge portion at three or more locations detected by the edge detection unit. .

As a result, the work hole position of the carrier arrange|positioned on the surface plate of a grinder can be detected stably, without being influenced by the illumination state around a carrier, the color of a carrier, etc.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view which shows schematically the whole structure of the grinding|polishing system to which the work-hole detection apparatus of Example 1 is applied.
Fig. 2 is a plan view schematically showing the overall configuration of a polishing system to which the work hole detection apparatus of Example 1 is applied.
3 is an explanatory diagram showing the measuring principle of the laser displacement meter.
4 is an explanatory diagram showing various detection positions set at the time of work hole detection, and edge positions to be detected.
Fig. 5 is an explanatory diagram showing various detection positions set at the time of estimating the wafer transfer state and movement trajectories of the laser displacement meter.
6 is a diagram showing measurement values of the laser displacement meter at the time of edge position detection.
Fig. 7A is an explanatory diagram showing the state of the wafer during normal wafer transfer. FIG. 7B is a diagram showing measured values of the laser displacement meter during normal wafer transfer.
Fig. 8(a) is an explanatory view showing the state of the wafer at the time of placing the wafer. FIG. 8(b) is a first view showing the measured values of the laser displacement meter at the time of placing the wafer. FIG. 8(c) is a second diagram showing the measured values of the laser displacement meter at the time of placing the wafer.
Fig. 9A is an explanatory view showing the state of the wafer when the wafer is floating. Fig. 9B is a diagram showing the measured values of the laser displacement meter when the wafer is floating.
Fig. 10 is a flowchart showing a wafer transfer control process executed in the main controller of the first embodiment.
11 is an explanatory diagram showing another example of setting an edge portion detection position.
12A is an explanatory diagram showing a first modified example of the movement trajectory of the laser displacement meter at the time of estimating the wafer conveyance state. Fig. 12B is a diagram showing the detection values of the laser displacement meter at the time of placing the wafer when the height of the wafer top surface is detected along the movement trajectory of the first modification.
13A is an explanatory diagram showing a second modified example of the movement trajectory of the laser displacement meter at the time of estimating the wafer conveyance state. Fig. 13B is a diagram showing the detection value of the laser displacement meter at the time of placing the wafer when the height of the wafer top surface is detected along the movement trajectory of the second modification.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the work-hole detection apparatus and work-hole detection method of this invention is demonstrated based on Example 1 shown in drawing.

(Example 1)

Hereinafter, the structure of the grinding|polishing system 1 to which the workhole detection apparatus of Example 1 is applied is demonstrated based on FIGS.

The polishing system 1 illustrated in FIG. 1 includes a polishing machine 10 , a wafer transfer machine 20 , and a main controller 30 .

The polishing machine 10 is a double-sided polishing apparatus for polishing both front and back surfaces of a thin-plate wafer 2 by an upper platen 11 and a lower platen 12 . Here, the wafer 2 is polished by the polishing pad 11a attached to the upper platen 11 and the polishing pad 12a attached to the lower platen 12 . Further, as shown in FIG. 2 , the wafer 2 is accommodated in the work hole 14 of the carrier 13 disposed on the polishing pad 12a, and is held by the carrier 13 to be polished.

The carrier 13 is a disk-shaped thin plate member thinner than the wafer 2 . The work hole 14 is a hole penetrating the carrier 13 , and is set to have an inner diameter that is slightly larger than the diameter of the wafer 2 . In addition, in the example shown in FIG. 2, although one work hole 14 is formed in the carrier 13, the number of the work holes 14 formed in the carrier 13 can be set arbitrarily.

Further, when the carrier 13 is disposed on the polishing pad 12a, the circumferential direction and position are defined, and the movement trajectory is constantly monitored, for example, by a controller (not shown) of the polishing machine 10 or the like. have. Thereby, the relative positional relationship between the lower surface plate 12 and the carrier 13 can always be grasped|ascertained, and the center position of the work hole 14 can be calculated|required by calculation based on this positional relationship. In addition, the center position of the work hole 14 computed based on the relative positional relationship of the lower surface board 12 and the carrier 13 is hereafter called "teaching position (alpha) (refer FIG. 4)." This teaching position α is defined by the X-Y coordinate system of the wafer transfer machine 20 .

The wafer transfer machine 20 is a robot arm that is driven based on a control command from the main controller 30 to automatically transfer the wafers 2 one by one. The wafer transfer machine 20 includes a transfer head 21 that detachably holds the wafer 2 and an arm 22 that moves the transfer head 21 in horizontal and vertical directions.

The wafer transfer machine 20 holds the wafers 2 taken out from a load port (not shown) in which a plurality of wafers 2 are accommodated by the transfer head 21 prior to the polishing process of the wafers 2 . do. Next, the arm part 22 is moved and the conveyance head 21 is conveyed to the upper position of the predetermined|prescribed work hole 14. As shown in FIG. Then, the wafer 2 is released from the transfer head 21 and placed in the work hole 14 .

In addition, after the wafer 2 is polished, the wafer transfer machine 20 moves the arm 22 to move the transfer head 21 to a position above the predetermined work hole 14 . Subsequently, the wafer 2 is held in the work hole 14 by the transfer head 21 , and the wafer 2 is taken out. Then, the arm 22 is moved to transport the wafer 2 to an unload port (not shown).

Moreover, the laser displacement meter R (distance measuring part) is mounted in the conveyance head 21 of Example 1. FIG. This laser displacement meter R, as shown in FIG. 3, irradiates a laser beam S1 to the target T, and based on the reflected light S2 reflected by the target T to the target T It is a distance sensor that measures the distance (L) of

When this laser displacement meter R drives the arm part 22 and moves the conveyance head 21, it moves integrally with the conveyance head 21. As shown in FIG. In addition, since the wafer transfer machine 20 can be moved while maintaining the height position of the laser displacement meter R constant, the laser displacement meter R can measure the thickness of the carrier 13 . In addition, this laser displacement meter R can measure the distance to the target object T even while it is moving by the wafer transfer machine 20. As shown in FIG. In addition, in order to remove the water|moisture content adhering to the target object T during the measurement of the laser displacement meter R, you may blow air with respect to the target object T.

The main controller 30 outputs a control command to the wafer transfer machine 20 to control the transfer of the wafer 2 by the wafer transfer machine 20, and a laser displacement meter ( Control the movement of R). In addition, the main controller 30 calculates the teaching position α based on the relative positional relationship between the lower surface plate 12 and the carrier 13, and uses the teaching position α to adjust the work hole 14 by using the teaching position α. Three or more positions of the edge portion (four in Example 1) are detected. Here, an "edge part" is an inner peripheral edge part of the work hole 14, and is the boundary of the work hole 14 and the carrier 13. As shown in FIG. And based on the detected position of the edge part, the center position of the work hole 14 is computed. In addition, both the position of the edge part of the work hole 14 and the center position of the work hole 14 are prescribed|regulated by the X-Y coordinate system of the wafer transfer machine 20 . In addition, the main controller 30 estimates the transfer state of the wafer based on the height of the upper surface of the wafer on which the transfer is completed after the wafer 2 is transferred.

That is, the main controller 30 includes the teaching position calculating unit 31 , the detection position setting unit 32 , the edge detecting unit 33 , the center calculating unit 34 , the transfer control unit 35 , the wafer state An estimating unit 36 is provided.

When information on the relative positional relationship between the lower surface plate 12 and the carrier 13 is input, the teaching position calculating unit 31 calculates the teaching position α based on the positional relation information. In addition, the positional relationship information of the lower surface plate 12 and the carrier 13 is input from the controller of the grinding|polishing machine 10, for example. Information on the teaching position α calculated by the teaching position calculating unit 31 is input to the detection position setting unit 32 .

When information of the teaching position α is input from the teaching position calculating unit 31, the detection position setting unit 32 detects various types of detection at the time of detecting the position of the work hole 14 based on the teaching position information. Set the location. In addition, the detection position setting unit 32 determines the center position of the work hole 14 calculated by the center calculating unit 34 after the wafer 2 is conveyed (hereinafter referred to as "actual center position β" (refer to FIG. 5 ). )") is input. Then, based on this actual center position information, various detection positions for estimating the conveyance state of the wafer 2 are set. Here, a "detection position" is a movement target point of the laser displacement meter R. The information of the detection position set by the detection position setting unit 32 is input to the conveyance control unit 35 .

Here, when detecting the position of the work hole 14, the height of the carrier 13, which is a reference value for detecting the edge of the work hole 14, the first edge position P11, the second edge position ( P13), the third edge position P15, and the fourth edge position P17 are detected at four positions (see Fig. 4). Therefore, the detection position setting unit 32 includes the reference detection position P10 shown in FIG. 4 , the first edge portion detection position P12 , the second edge portion detection position P14 , and the third edge A negative detection position P16 and a fourth edge portion detection position P18 are set. In addition, the "reference detection position P10" is a movement target point of the laser displacement meter R at the time of detecting the height of the carrier 13. As shown in FIG. "The 1st edge part detection position P12" is a movement target point of the laser displacement meter R at the time of detecting the 1st edge position P11. "The 2nd edge part detection position P14" is a movement target point of the laser displacement meter R at the time of detecting the 2nd edge position P13. "The 3rd edge part detection position P16" is a movement target point of the laser displacement meter R at the time of detecting the 3rd edge position P15. "The 4th edge part detection position P18" is a movement target point of the laser displacement meter R at the time of detecting the 4th edge position P17.

In addition, the first edge portion detection position P12, the second edge portion detection position P14, the third edge portion detection position P16, and the fourth edge portion detection position P18 are , is set at a position where it is possible to surround the teaching position α by a line segment γ that sequentially connects these four positions. That is, the detection position setting unit 32 sets three or more detection positions that can surround the teaching position α when setting the edge portion detection position.

And the reference detection position P10 is set at the position estimated to the board|substrate part of the carrier 13 based on the teaching position (alpha). In addition, the "substrate part of the carrier 13" is a position outside the work hole 14, and is a flat part in which the work hole 14, a dummy hole, etc. are not formed at all. In addition, the 1st edge part detection position P12, the 2nd edge part detection position P14, the 3rd edge part detection position P16, and the 4th edge part detection position P18 are all teaching positions (alpha) here. ), it is set at a position estimated to be inside the work hole 14 .

In addition, when estimating the conveyance state of the wafer 2, in Example 1, the height of the carrier 13 which becomes a reference value at the time of judging the wafer conveyance state, and the height of the upper surface of the wafer 2 after which conveyance is completed are detected. do. Therefore, the detection position setting part 32 sets the reference detection position P20 and the height detection start position P21 shown in FIG. In addition, the "reference detection position P20" is a movement target point of the laser displacement meter R at the time of detecting the height of the carrier 13. As shown in FIG. The "height detection start position P21" is a movement target point of the laser displacement meter R when detecting the upper surface height of the wafer 2 .

Here, the reference detection position P20 is set at a position estimated to be the substrate portion of the carrier 13 based on the actual center position β. Further, the height detection start position P21 is set at a position estimated to be the wafer 2 based on the actual center position β.

When the measurement value of the laser displacement meter R is input, the edge detection unit 33 sets the position of the edge portion of the work hole 14 at three or more locations (the first edge position P11 in the first embodiment) based on the measurement value. to four locations of the fourth edge position P17] are detected. The positional information of the edge portion detected by the edge detection unit 33 is input to the center operation unit 34 .

This edge detection part 33 sets a reference value based on the measurement value obtained by first moving the laser displacement meter R to the reference detection position P10, when detecting an edge part. Here, a value obtained by subtracting a predetermined value from the measured value obtained at the reference detection position P10 is used as a reference value. Then, it is judged whether the measured value obtained while moving the laser displacement meter R from the 1st edge part detection position P12 along a predetermined|prescribed trajectory exceeds a reference value. Then, the first edge position P11 is detected based on the movement amount x of the laser displacement meter R at the time when the measured value exceeds the reference value and the first edge portion detection position P12 (FIG. 6). Reference).

In addition, the edge detection part 33 also moves the laser displacement meter R also about the 2nd edge position P13, the 3rd edge position P15, and the 4th edge position P17, The 1st edge position It is detected in the same way as (P11). That is, the edge detection unit 33 detects the position of the edge portion (first edge position P11, etc.) while moving the laser displacement meter R from the edge portion detection position (first edge portion detection position P12, etc.). This is repeated until three or more positions of the edge portions (such as the first edge position P11) are detected.

In the center calculating part 34, the positional information of the edge part of three or more places (in Example 1, 4 places of the 1st edge position P11 - the 4th edge position P17) is input from the edge detection part 33. As shown in FIG. And based on the positional information of this edge part, the actual center position (beta) is computed. The information of the actual center position β calculated by the center operation unit 34 is input to the conveyance control unit 35 . In addition, the actual center position (β) can be obtained using the position information of the three or more edge portions and a general equation of a circle.

The transfer control unit 35 receives information on various detection positions (such as the reference detection position P10 ) from the detection position setting unit 32 , and, based on the various detection positions, sends the information to the wafer transfer machine 20 . Outputs a control command. Then, in a predetermined sequence and timing, the laser displacement meter R is moved by using various detection positions as movement target points. In addition, after moving the laser displacement meter R to a predetermined detection position (such as the first edge position P11 ), the transfer control unit 35 outputs a control command to the wafer transfer machine 20 in a predetermined direction. to move the laser displacement meter (R).

The wafer state estimating unit 36 receives the measured value of the laser displacement meter R after the wafer 2 is transferred, and estimates the transfer state of the transferred wafer 2 based on the measured value. In addition, the conveyance state information estimated by the wafer state estimation part 36 may be input to the controller of the grinding|polishing machine 10 etc., for example, and the operator of the grinding|polishing system 1 may be notified.

When estimating the transfer state of the wafer, the wafer state estimating unit 36 is configured to first move the laser displacement meter R to the reference detection position P20 based on a measurement value obtained in a reference range (upper limit threshold and lower threshold) is set. Then, the laser displacement meter R is moved to the height detection start position P21, and from this height detection start position P21, a predetermined trajectory (here, annular trajectory 3 along the peripheral edge of the wafer 2) )], it is determined whether or not the measured value (the height of the upper surface of the wafer) obtained while moving along the direction exceeds the reference range.

For example, as shown in FIG. 7A , when the wafer 2 is normally placed in the work hole 14 , the measured value obtained while the laser displacement meter R moves along the annular trajectory 3 . is within the reference range (refer to Fig. 7(b)). That is, when it is determined that the measured value falls within the reference range, the wafer state estimating unit 36 estimates that the wafer 2 is normally placed.

In contrast, as shown in FIG. 8A , when the wafer 2 is placed on the edge of the work hole 14 , the laser displacement meter R is measured while moving along the annular trajectory 3 . On the way, the measured value exceeds the reference range (see Fig. 8(b)). In addition, depending on the relationship between the setting position of the height detection start position P21 and the mounting position of the wafer 2, the measured value shown in FIG. 8(c) is obtained, but even in this case, the laser displacement meter R During the measurement while moving along the annular trajectory 3, the measured value exceeds the reference range. In addition, as shown in Fig. 9(a), even when the wafer 2 is placed in the work hole 14, even if it is floating from the polishing pad 12a under the influence of slurry or water, the laser displacement meter ( During the measurement while R) moves along the annular trajectory 3, the measured value exceeds the reference range (see Fig. 9(b)). Therefore, when it is determined that the measured value exceeding the reference range is obtained, the wafer state estimating unit 36 estimates that the wafer 2 is not normally placed.

Hereinafter, each step of the wafer transfer control process executed by the main controller 30 of the first embodiment will be described based on the flowchart shown in FIG. 10 . In addition, this wafer conveyance control process is repeatedly performed until the wafer 2 is arrange|positioned in the workholes 14 of all the carriers 13 on the polishing pad 12a.

In step S1, it is determined whether or not the transfer of the wafer 2 is to be started. In the case of 'yes' (transfer start), the process proceeds to step S2. In the case of 'no' (no return), step S1 is repeated. In addition, the conveyance start determination is performed by the conveyance control part 35, for example.

In step S2 (first step), following the determination of the start of conveyance in step S1 , the teaching position calculation unit 31 calculates the teaching position, and the detection position setting unit 32 calculates the teaching position α ) is read, and the process proceeds to step S3.

In step S3 (first step), following the reading of the teaching position information in step S2, the detection position setting unit 32 detects the position of the work hole 14 based on the teaching position information. Various detection positions (reference detection position P10, first edge portion detection position P12, second edge portion detection position P14, third edge portion detection position P16, fourth edge portion detection position P18 )], and the process proceeds to step S4.

In step S4 (first step), following the setting of the detection position in step S3, a control command is output from the transfer control unit 35 to the wafer transfer machine 20, and the reference detection position P10 set in step S3 is The laser displacement meter R is moved by using as a movement target point, and the process proceeds to step S5.

In step S5 (first step), following the movement of the laser displacement meter R in step S4, the distance to the reference detection position P10 is measured by the laser displacement meter R, and the process proceeds to step S6. Here, since the reference detection position P10 is set at the position estimated by the board|substrate part of the carrier 13, the carrier height is detected. And based on this carrier height, the reference value at the time of detecting the edge part of the work hole 14 is set.

In step S6 (first step), following the detection of the carrier height in step S5, a control command is output from the transfer control unit 35 to the wafer transfer machine 20, and the first edge portion detection position set in step S3 The laser displacement meter R is moved using (P12) as the movement target point, and the process proceeds to step S7.

In step S7 (first step), following the movement of the laser displacement meter R in step S6, while moving the laser displacement meter R in a predetermined direction, the carrier 13 present below by the laser displacement meter R ) or the distance to the polishing pad 12a is measured. Then, based on the measured value obtained at this time and the reference value set from the carrier height detected in step S5 , the edge detection unit 33 detects the first edge position P11 , and the process proceeds to step S8 .

In step S8 (first step), following the detection of the first edge position P11 in step S7, a control command is output from the transfer control unit 35 to the wafer transfer machine 20, and the first edge position P11 set in step S3 is outputted. 2 Using the edge portion detection position P14 as the movement target point, the laser displacement meter R is moved, and the process proceeds to step S9.

In step S9 (first step), following the movement of the laser displacement meter R in step S8, while moving the laser displacement meter R in a predetermined direction, the carrier 13 present below by the laser displacement meter R ) or the distance to the polishing pad 12a is measured. Then, based on the measured value obtained at this time and the reference value set in step S5 , the edge detection unit 33 detects the second edge position P13 , and the process proceeds to step S10 .

In step S10 (first step), following the detection of the second edge position P13 in step S9, a control command is output from the transfer control unit 35 to the wafer transfer machine 20, and the second edge position P13 set in step S3 is output. 3 Using the edge portion detection position P16 as the movement target point, the laser displacement meter R is moved, and the process proceeds to step S11.

In step S11 (first step), following the movement of the laser displacement meter R in step S10, while moving the laser displacement meter R in a predetermined direction, the carrier 13 present below by the laser displacement meter R ) or the distance to the polishing pad 12a is measured. Then, based on the measured value obtained at this time and the reference value set in step S5 , the edge detection unit 33 detects the third edge position P15 , and the process proceeds to step S12 .

In step S12 (first step), following the detection of the third edge position P15 in step S11, a control command is output from the transfer control unit 35 to the wafer transfer machine 20, and the first set in step S3 4 Using the edge portion detection position P18 as the movement target point, the laser displacement meter R is moved, and the process proceeds to step S13.

In step S13 (first step), following the movement of the laser displacement meter R in step S12, while moving the laser displacement meter R in a predetermined direction, the carrier 13 present below by the laser displacement meter R ) or the distance to the polishing pad 12a is measured. Then, based on the measured value obtained at this time and the reference value set in step S5 , the edge detection unit 33 detects the fourth edge position P17 , and the process proceeds to step S14 .

In step S14 (second step), following the detection of the fourth edge position P17 in step S13, the first edge position P11, the second edge position P13, the third edge position P15, 4 Based on the edge position P17, the center calculating section 34 calculates the actual center position β, and the flow advances to step S15.

In step S15 , following the calculation of the actual center position β in step S14 , a control command is output from the transfer control unit 35 to the wafer transfer machine 20 to transfer the wafer 2 into the work hole 14 . and proceeds to step S16. At this time, the conveyance control part 35 calculates|requires the difference (deviation amount) of the teaching position (alpha) calculated by the teaching position calculating part 31, and the actual center position (beta) calculated by the center calculating part 34. As shown in FIG. Then, with respect to the teaching position α, the calculated difference (deviation amount) is corrected to set the target position. Then, by outputting a control command for matching the center position of the wafer 2 held by the transfer head 21 to the target position, the arm unit 22 so that the wafer 2 is placed at the center of the work hole 14 . ) to control

In step S16 (third step), following the transfer of the wafer 2 in step S15 , a control command is output from the transfer control unit 35 to the wafer transfer machine 20 , and the transfer is completed on the upper surface of the wafer 2 . The height is detected, and the process proceeds to step S17.

Here, before detecting the upper surface height of the wafer 2 , first, the detection position setting unit 32 sets the reference detection position P20 and the height detection start position P21 based on the actual center position β. to set Then, the conveyance control part 35 moves the laser displacement meter R to the reference detection position P20, and the laser displacement meter R measures the distance to the reference detection position P20. Further, the wafer state estimating unit 36 sets the reference ranges (the upper limit threshold value and the lower limit threshold value) based on the measured values obtained at this time. Then, the conveyance control part 35 moves the laser displacement meter R to the height detection start position P21. Then, the laser displacement meter R detects the upper surface height of the wafer 2 while moving along a preset annular trajectory 3 from the height detection start position P21.

In step S17 (fourth step), following the detection of the upper surface height of the wafer 2 in step S16, the upper surface height of the wafer 2 detected in step S16 and the distance to the reference detection position P20 set Based on the reference range, the wafer state estimating unit 36 estimates the transfer state of the wafer 2, and proceeds to the end.

Hereinafter, the "workhole position detection action" of the workhole detection apparatus and workhole detection method of Example 1 is demonstrated.

In order to polish the wafer 2 in the polishing system 1 of Example 1, the wafer 2 is automatically transferred onto the lower platen 12 of the polishing machine 10 using the wafer transfer machine 20 . do. Here, the polishing pad 12a is previously attached to the lower surface plate 12, and the carrier 13 which has the work hole 14 is arrange|positioned thereon. That is, the wafer transfer machine 20 needs to transfer the wafer 2 in the determined posture in the determined work hole 14 .

On the other hand, as for the carrier 13, the circumferential direction and position at the time of arrange|positioning on the polishing pad 12a are prescribed|regulated, and a movement trajectory is constantly monitored. Therefore, the relative positional relationship between the lower surface plate 12 and the carrier 13 is always grasped, and the center position of the work hole 14 is also calculated|required as the teaching position (alpha). However, due to the backlash of the sun gear or internal gear of the grinding machine 10, the backlash of the carrier, and the increase in backlash due to wear, the actual center position of the work hole 14 is deviated from the teaching position α. There are cases. Therefore, when the wafer 2 is conveyed with the teaching position α as the target position, there may be cases in which the wafer 2 cannot be conveyed properly.

Therefore, in the wafer transfer machine 20 of the first embodiment, in order to recognize the position of the work hole 14 in which the wafer 2 is to be placed, the laser displacement meter R is used before the wafer 2 is placed. The position of the edge portion of the work hole 14 in more than one place is detected, and the actual center position β defined by the XY coordinate system of the wafer transfer machine 20 is calculated. Then, the wafer 2 is placed by correcting the difference between the actual center position β and the previously obtained teaching position α.

That is, when the transfer control unit 35 of the main controller 30 executes step S1 of the flowchart shown in FIG. 10 and determines that the transfer of the wafer 2 is to be started, step S2 is executed. In this way, the teaching position calculating unit 31 calculates the teaching position α, and the detection position setting unit 32 reads the information of the teaching position α calculated by the teaching position calculating unit 31 .

Then, the detection position setting unit 32 executes step S3, and based on the teaching position information, various detection positions (reference detection position P10, first detection position P10) when detecting the position of the work hole 14 . 1 edge part detection position P12, 2nd edge part detection position P14, 3rd edge part detection position P16, 4th edge part detection position P18] are set.

Here, the first edge portion detection position P12, the second edge portion detection position P14, the third edge portion detection position P16, and the fourth edge portion detection position P18 connect these four positions. It is set at a position where it is possible to surround the teaching position α by the line segment γ. In addition, the reference detection position P10 is set at the position estimated to be the board|substrate part of the carrier 13 based on the teaching position (alpha).

When the detection position is set by the detection position setting unit 32, steps S4 and S5 are executed, and the conveyance control unit 35 moves the laser displacement meter R using the reference detection position P10 as the movement target point. and the distance to the reference detection position P10 is measured by the laser displacement meter R. Here, the reference detection position P10 is a position where the work hole 14 of the carrier 13 is not present. Therefore, the laser displacement meter R can detect the height of the carrier 13 .

When the carrier height is detected, steps S6 and S7 are executed. That is, the conveyance control part 35 makes the 1st edge part detection position P12 a movement target point, and moves the laser displacement meter R. The laser displacement meter R measures the distance to the object (the carrier 13 or the polishing pad 12a) while moving from the first edge portion detection position P12. The edge detection part 33 compares the measured value obtained at this time with the reference value calculated|required from the carrier height detected previously, and detects the 1st edge position P11.

When the first edge position P11 is detected, steps S8 and S9 are executed. That is, the conveyance control part 35 makes the 2nd edge part detection position P14 a movement target point, and moves the laser displacement meter R. The laser displacement meter R measures the distance to the object (the carrier 13 or the polishing pad 12a) while moving from the second edge portion detection position P14. The edge detection part 33 compares the measured value obtained at this time with the reference value calculated|required from the previously detected carrier height, and detects the 2nd edge position P13.

When the second edge position P13 is detected, steps S10 and S11 are executed. That is, the conveyance control part 35 makes the 3rd edge part detection position P16 a movement target point, and moves the laser displacement meter R. The laser displacement meter R measures the distance to the object (the carrier 13 or the polishing pad 12a) while moving from the third edge portion detection position P16. The edge detection part 33 compares the measured value obtained at this time with the reference value calculated|required from the previously detected carrier height, and detects the 3rd edge position P15.

When the third edge position P15 is detected, steps S12 and S13 are executed. That is, the conveyance control part 35 makes the 4th edge part detection position P18 as a movement target point, and moves the laser displacement meter R. The laser displacement meter R measures the distance to the object (the carrier 13 or the polishing pad 12a) while moving from the fourth edge portion detection position P18. The edge detection part 33 compares the measured value obtained at this time with the reference value calculated|required from the previously detected carrier height, and detects the 4th edge position P17.

When four edge positions (first edge position P11, second edge position P13, third edge position P15, fourth edge position P17, hereinafter the same) are detected, step S14 is executed and , The center calculating unit 34 calculates the actual center position β using the information on the four edge positions and the equation of the circle.

Then, when the actual center position β is calculated, the conveyance control unit 35 executes step S15. That is, the conveyance control unit 35 obtains the difference (deviation amount) between the teaching position α and the actual center position β, corrects the teaching position α according to this difference (deviation amount), and sets the target position A control command for matching the center position of the wafer 2 is outputted to the , and the wafer 2 is placed at the center of the work hole 14 .

As described above, in Example 1, the actual center position β is detected based on the information on the positions of the edge portions at four locations, but the positions of the four edge portions are determined by a laser displacement meter that measures the distance to the object T. It is detected based on the measured value obtained by measuring the distance to the object T while moving (R). Therefore, the position of the edge part of the work hole 14 can be detected, without being influenced by the illumination state around a detection apparatus, the color of the carrier 13, etc.

Thereby, the position of the work hole 14 of the carrier 13 arrange|positioned on the lower surface plate 12 of the grinder 10 can be detected stably. And since the position of the work hole 14 can be grasped|ascertained stably, it becomes possible to arrange|position the wafer 2 precisely in the determined attitude|position at the determined position.

In addition, the distance to the target object T is measured by the laser displacement meter R which measures this distance by the reflected light of a laser beam. Therefore, since the distance can be measured without contacting the carrier 13 or the polishing pad 12a, it can measure with high precision, moving the distance L to the object T. Thereby, the position of the edge part of the work hole 14 can be detected with high precision.

Further, in the first embodiment, this laser displacement meter R is mounted on the transfer head 21 of the wafer transfer machine 20 that transfers the wafer 2 . Therefore, the laser displacement meter R can be moved using the wafer transfer machine 20 that moves to the vicinity of the work hole 14 , and a mechanism for moving the laser displacement meter R is not separately provided, but is positioned at an appropriate position. By moving the laser displacement meter R, the position of the edge portion of the work hole 14 can be detected with high accuracy.

Further, in the first embodiment, the relative positional relationship between the lower surface plate 12 and the carrier 13 is monitored, and the teaching position calculating unit 31 determines the relative positional relationship between the lower surface plate 12 and the carrier 13 by the teaching position calculation unit 31 . Based on this, the teaching position α is calculated. Thereby, the detection position setting part 32 can set various detection positions at the time of detecting the position of the work hole 14 based on the teaching position (alpha). That is, the position of the edge portion of the work hole 14 can be detected based on the teaching position α. For this reason, it is not necessary to move the laser displacement meter R unnecessarily, and the position detection of the edge part of the work hole 14 in a short time becomes possible.

In addition, the edge portion detection positions (first edge portion detection position P12, second edge portion detection position P14, third edge portion detection position P16, fourth edge The sub-detection position P18, hereinafter the same] is set at a position where the teaching position α can be surrounded by the line segment γ connecting these four positions.

That is, when detecting the position of the edge portion of the work hole 14 , the detection position setting unit 32 sets three or more edge portion detection positions that can surround the teaching position α. And the edge detection part 33 repeats detecting the position of the edge part of the work hole 14 while moving the laser displacement meter R from each edge part detection position, The position of the edge part of the work hole 14 is 3 Detect multiple abnormalities. For this reason, the position of the edge portion of the work hole 14 detected by the edge detection unit 33 becomes a position surrounding the teaching position α, as shown in FIG. 4 , and the edge of the work hole 14 is It is possible to improve the arithmetic precision at the time of calculating the actual center position β based on the negative position.

Furthermore, in Example 1, the positions of the edge portions at four locations are detected. Therefore, when calculating the actual center position β, it is possible to establish four calculation expressions, for example, compared with the case where the position of the edge portion of the work hole 14 is detected at three locations, the calculation precision can be improved. .

Hereinafter, the "wafer conveyance state estimating action" of the workhole detection apparatus and workhole detection method of the first embodiment will be described.

In the polishing system 1 of Example 1, when the wafer 2 is conveyed, step S16 in the flowchart shown in FIG. 10 is executed to set the upper surface height of the wafer 2 . That is, first, the detection position setting unit 32 sets the reference detection position P20 and the height detection start position P21 based on the actual center position β. Then, the transfer control unit 35 drives the wafer transfer machine 20 to move the laser displacement meter R to the reference detection position P20, and measures the distance to the reference detection position P20. Here, the reference detection position P20 is a position estimated by the substrate part of the carrier 13 . Therefore, the laser displacement meter R can detect the height of the carrier 13 . In addition, at this time, the wafer state estimating unit 36 sets a reference range for estimating the transfer state of the wafer 2 based on the carrier height. Then, the transfer control unit 35 drives the wafer transfer machine 20 to move the laser displacement meter R from the height detection start position P21 along the annular trajectory 3 . The laser displacement meter R measures the distance to the wafer 2 while moving, and detects the upper surface height of the wafer 2 .

When the upper surface height of the wafer 2 is detected by the laser displacement meter R, step S17 is executed, and the wafer state estimating unit 36 calculates the detected upper surface height of the wafer 2 and the preset reference range. By comparison, the conveyance state of the wafer 2 is estimated.

As described above, in the first embodiment, the wafer state estimation unit 36 for estimating the transfer state of the wafer 2 based on the upper surface height of the transferred wafer 2 measured by the laser displacement meter R is provided. are doing

As a result, when the wafer 2 is placed on the edge of the work hole 14 (see Fig. 8(a)) or when the wafer 2 is floating from the polishing pad 12a (see Fig. 9((a)) a) etc.], when it is estimated that the wafer 2 is not disposed at the determined position and in the determined posture, this transfer information is notified to the operator of the polishing system 1 , so that the transfer of the wafer 2 is completed. The position and posture can be corrected, and the polishing process of the wafer 2 can be stopped. That is, it is possible to prevent the wafer 2 from being polished at the determined position and not arranged in the determined posture.

As mentioned above, although the work-hole detection apparatus and work-hole detection method of this invention have been demonstrated based on Example 1, about a specific structure, it is not limited to this Example, The summary of invention according to each claim of a claim As long as it does not deviate from the above, changes or additions in design are permitted.

In Example 1, an example is shown in which the edge detection position is set at a position where the teaching position α can be surrounded by the line segment γ that sequentially connects the four edge detection positions. I never do that. Since it is enough to detect the position of the edge portion of the work hole 14 at three or more locations, as shown in FIG. 11, three or more edge detection positions [shown in FIG. 11] are located at positions that do not surround the teaching position α. In the example, the first edge part detection position P12', the second edge part detection position P14', the third edge part detection position P16', the fourth edge part detection position P18'] are set. good. That is, the edge portion detection position can be set arbitrarily.

In addition, in Example 1, although the example was shown in which all the edge part detection positions were set to the position estimated to be inside the work hole 14 based on the teaching position (alpha), it is not limited to this. You may set the edge part detection position outside the work hole 14 (a position estimated to be the board|substrate part of the carrier 13). In addition, when measuring while setting the edge part detection position to the position inside the work hole 14 and moving the laser displacement meter R from the inside of the work hole 14 toward the outside, the movement of the laser displacement meter R By spraying air on the carrier 13 in accordance with this, moisture adhering to the edge portion of the work hole 14 is easily removed, and generation of measurement errors can be suppressed.

In addition, the measurement value obtained by moving the laser displacement meter R from an arbitrary position in an arbitrary direction without providing the teaching position calculating part 31 or the detection position setting part 32 and setting an edge part detection position. may be used to detect the position of the edge portion of the work hole 14 .

Further, in Example 1, an example of estimating the conveyance state of the wafer 2 based on the measurement value obtained by moving the laser displacement meter R along the annular trajectory 3 along the peripheral edge of the wafer 2 is shown. It was. However, since the height of the transferred wafer 2 can be detected at a plurality of positions, the present invention is not limited thereto.

For example, as shown in (a) of FIG. 12, the laser displacement meter R along two straight trajectories (first trajectory 4, second trajectory 5) orthogonal to the actual center position β. You may estimate the conveyance state of the wafer 2 based on the measured value obtained by moving. At this time, as shown in FIG. 12B , even if the measured value obtained by moving the laser displacement meter R along the second trajectory 5 is a constant value, the laser displacement gauge R along the first trajectory 4 When the measured value obtained by moving ) exceeds the upper limit threshold, the wafer state estimating unit 36 determines that a measured value exceeding the reference range has been obtained, and indicates that the wafer 2 is not normally placed. estimate

In addition, as shown in Fig. 13 (a), the laser displacement meter ( ) is positioned above the arbitrary six measurement points ( 6a , 6b , 6c , 6d , 6e , 6f ) in the vicinity of the peripheral edge of the wafer 2 . R) may be moved, and the conveyance state of the wafer 2 may be estimated based on the height position of the wafer 2 at each of the measurement points 6a to 6f. At this time, as shown in (b) of FIG. 13 , when any one of the six measurement points 6a to 6f exceeds the reference range, the wafer state estimating unit 36 determines that the wafer 2 is normally disposed. presumed not to be

Further, in Example 1, an example of using a laser displacement meter R for measuring a distance by means of a reflected light S2 of a laser beam as a distance measuring unit for measuring the distance to the object T is shown, but it is not limited to this does not For example, a distance measuring device or the like may be used in which a stretching measuring rod is extended to the object T, and the distance is measured by the length of the rod.

Moreover, in Example 1, although the example of conveying the wafer 2 to one work hole 14 formed in the carrier 13 was shown, the several work hole 14 may be formed in the carrier 13. . In this case, for example, the actual center positions of the plurality of work holes 14 may be sequentially detected one by one, and the wafers 2 may be sequentially placed in the work holes 14 for which the actual center positions are detected.

In addition, the detection of the actual center position β of the work hole 14 may be performed in a state in which the wafer 2 is held by the transfer head 21 or in a state in which the wafer 2 is not held. also good In the case of detecting the actual center position β while holding the wafer 2 , it is not necessary to drive the arm 22 to hold the wafer 2 after the detection of the actual center position β. . Therefore, it is possible to suppress an increase in the transfer time of the wafer 2 .

1: Polishing system 2: Wafer
10: grinding machine 11: table plate
12: lower class 13: carrier
14: work hole 20: wafer transfer machine
21: transfer head 22: arm part
30: main controller 31: teaching position calculation unit
32: detection position setting unit 33: edge detection unit
34: center operation unit 35: conveyance control unit
36: Wafer state estimation unit R: Laser displacement meter (distance measurement unit)
α: Teaching position β: Actual center position

Claims (10)

In the work hole detection apparatus for detecting the position of the work hole of the carrier arranged on the surface plate of the grinder,
a distance measuring unit for measuring the distance to the object;
an edge detection unit for detecting three or more positions of the edge portion of the work hole by using the measured value of the distance measurement unit;
Based on the positions of the three or more edge portions detected by the edge detection unit, a center calculating unit for calculating the center position of the work hole
Workhole detection device comprising a. According to claim 1,
The distance measuring unit is a workhole detection device, characterized in that the laser displacement meter for measuring the distance by the reflected light of the laser beam. According to claim 1,
Based on the relative positions of the surface plate and the carrier, a teaching position calculating unit for calculating the center position of the work hole
Workhole detection device comprising a. 3. The method of claim 2,
Based on the relative positions of the surface plate and the carrier, a teaching position calculating unit for calculating the center position of the work hole
A workhole detection device comprising a. 5. The method according to any one of claims 1 to 4,
A wafer state estimating unit for estimating the transfer state of the wafer based on the upper surface height of the transferred wafer measured by the distance measuring unit
Workhole detection device comprising a. 5. The method according to any one of claims 1 to 4,
The distance measuring unit is mounted on a wafer transporter that transports a wafer into the workhole. 6. The method of claim 5,
The distance measuring unit is mounted on a wafer transporter that transports a wafer into the workhole. In the work hole detection method for detecting the position of the work hole of the carrier disposed on the surface plate of the polishing machine,
A first step of detecting three or more positions of the edge portion of the work hole based on the measured value obtained by measuring the distance to the object while moving the distance measuring unit;
A second step of calculating the center position of the work hole based on the position of the edge portion at three or more places
Workhole detection method comprising a. 9. The method of claim 8,
In the first step, when detecting the position of the edge portion, three or more edge portion detection positions capable of enclosing the center position of the work hole calculated from the relative positions of the surface plate and the carrier are set, and the edge portion A workhole detection method, characterized in that the position of the edge portion is detected at three or more locations while the distance measurement portion is moved from the detection position. 10. The method according to claim 8 or 9,
a third step of detecting the height of the top surface of the transferred wafer using the distance measuring unit after the transfer of the wafer;
A fourth step of estimating a conveyance state of the wafer based on the upper surface height of the wafer
Workhole detection method comprising a.

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