WO2002007236A1

WO2002007236A1 - Displacement detector and processing system

Info

Publication number: WO2002007236A1
Application number: PCT/JP2001/005318
Authority: WO
Inventors: Masaki Kondo
Original assignee: Tokyo Electron Limited
Priority date: 2000-07-19
Filing date: 2001-06-21
Publication date: 2002-01-24
Also published as: JP2002043394A

Abstract

A displacement detector capable of accurately detecting the presence or absence and the amount of the displacement of a disk-like processed body (W) having an orientation identifying cut-out part (OF) on the peripheral part thereof, comprising three profile detection sensors (36-1 to 36-3, 38-1 to 38-3) disposed so as to detect the position of the peripheral profile of the processed body excluding the orientation identifying cut-out part and a displaced amount calculation part (40) for calculating the amount of displacement between the center position of the processed body and a reference origin based on the values detected by the three profile detection sensors, whereby the presence or absence and the amount of the displacement of the processed body can be provided accurately without being affected by the manufacturing error and thermal telescoping of the processed body.

Description

Description Positional deviation detection device and processing system

The present invention relates to a position shift detecting device for detecting a position shift occurring in the course of conveyance, and a processing system having the position shift detecting device and performing a predetermined process on an object to be processed such as a semiconductor wafer. Background art

Generally, in order to manufacture a semiconductor integrated circuit such as an IC, it is necessary to repeatedly perform various processes such as film formation, oxidative diffusion, etching, and annealing on the surface of a semiconductor wafer such as a silicon substrate. In this case, in order to improve the processing efficiency, a processing chamber for each processing is connected to one common transfer chamber and provided as a so-called class tool tool, and the wafer is transported so as to walk between the processing chambers. However, a series of processes as described above are performed.

FIG. 10 is a schematic configuration diagram showing an example of the conventional processing system as described above. As shown in the figure, the processing system 2 has a plurality of, here three processing chambers 8A to 8C, respectively, which are connected to a common transfer chamber 4 which can be evacuated via gate valves 6A to 6C. It is composed by connecting. In each of the processing chambers 8A to 8C, a mounting table 10A to 10C on which an electrostatic chuck for adsorbing and holding a wafer by, for example, electrostatic force is disposed on the upper surface is provided. The common transfer chamber 4 is connected to two cassette chambers 14A and 14B for accommodating cassettes containing substantially disc-shaped semiconductor wafers via gate valves 12A and 12B. Is done. In the common transfer chamber 4, there is provided a transfer mechanism 16, for example, composed of an articulated arm capable of turning and bending and extending. The transfer mechanism 16 holds the semiconductor wafer W, and transfers the semiconductor wafer W to each other. The paper is transferred between the cassette chambers 14A and 14B and the processing chambers 8A to 8C and between the processing chambers 8A to 8C.

By the way, when receiving the wafer W from the mounting table 10 A to 10 C, the wafer W However, when the charge is insufficient, the wafer may be held up by the transfer mechanism while the wafer is jumped up due to residual charges and a positional shift occurs. Therefore, when the semiconductor wafer W is held and transferred by the transfer mechanism 16, the center of the semiconductor wafer W is allowed to the holding center 18 A at the tip of the arm 18 of the transfer mechanism 16 with high accuracy. It is necessary to transfer the wafer W with almost no misalignment in the condition of matching within the capacity.

For this reason, in the related art, for example, Japanese Patent Application Laid-Open No. H10-2243732, Japanese Patent Application Laid-Open No. H10-2476791, and US Pat. Japanese Patent Application Laid-Open Publication No. H10-210, etc. has proposed a position shift detecting device. As an example of this, for example, a detection device as shown in FIG. 10 will be described. In the common transfer chamber 4, a predetermined interval is provided in the vicinity of the gate valves 6A to 6C of the processing chambers 8A to 8C. A pair of line sensors 20 and 22 are arranged, and when the wafer W passes there, it is temporarily stopped at a predetermined position to detect two edges of the wafer (positions of peripheral contours). Based on the detected value, the degree of displacement of the wafer center at that time from the reference origin is determined.

However, disc-shaped semiconductor wafers have small but inevitable manufacturing errors, so their diameters may vary. The diameter of the semiconductor wafer may be slightly thermally expanded. In such a situation, the conventional detection device using the pair of line sensors 20 and 22 as described above may not be able to sufficiently detect the occurrence of the displacement and the amount of the displacement. For example, when the center of the semiconductor wafer W held by the transfer mechanism 16 is slightly displaced from the reference origin toward the center of the transfer mechanism 16, and the diameter of the semiconductor wafer is a manufacturing error. When it is slightly larger than the reference diameter, it is recognized that there is no displacement in the calculation based on the detection values of the two line sensors 20 and 22 even though the wafer W has a displacement, Alternatively, there has been a problem that the displacement amount is erroneously recognized.

Further, the position shift detecting device disclosed in Japanese Patent Application Laid-Open No. 10-247681 uses three sensors, one of which is a notch (a V-shaped notch). ), The wafer manufacturing error and heat It is difficult to sufficiently respond to fluctuations in the wafer diameter due to expansion and contraction.

In particular, due to the progress of miniaturization of semiconductor devices, in the current semiconductor wafer manufacturing, the error of the diameter is only allowed to be about ± 0.2 mm, and the amount of the positional deviation is accurately detected. And it needs to be corrected.

The present invention has been made in view of the above circumstances, and an object of the present invention is to accurately determine the presence / absence of a position shift and the amount of position shift of a target object without being affected by manufacturing errors or thermal expansion and contraction of the target object. It is an object of the present invention to provide a position shift detecting device and a processing system which can be used. Disclosure of the invention

A first feature of the present invention is a position shift detecting device for detecting a position shift of a disk-shaped object to be processed having a direction-recognizing cutout portion in a peripheral portion, wherein the processing target excluding the direction-recognition cutout portion is provided. Three contour detection sensors arranged to detect the position of the peripheral contour of the body, and a reference position between the center position of the object to be processed and a reference origin obtained based on each detection value of the three contour detection sensors. And a shift amount calculating unit for calculating a shift amount between the two. As a result, the three contour detection sensors can detect the peripheral contour of the object to be processed at a position excluding the direction recognition notch such as a notch or an orientation flat. The center position of the object to be processed can be obtained without affecting the manufacturing error of the diameter or the thermal expansion and contraction. As a result, the presence or absence of the position shift and the amount of the position shift can be obtained with high accuracy.

A second feature of the present invention is that the three contour detection sensors are arranged substantially 120 degrees apart from each other in the circumferential direction around the reference origin. According to this, it is possible to further improve the detection accuracy of the displacement amount.

A third feature of the present invention is that an installation position of the contour detection sensor is determined in consideration of a circumferential length of the direction recognition cutout portion and a maximum deviation amount allowed for the object to be processed. That is. Accordingly, even if the maximum displacement allowed for the object to be processed occurs, the positional deviation of the object to be processed can be sufficiently detected without being affected by the notch.

A fourth feature of the present invention is that the contour detection sensor has a light-emitting element that emits inspection light, and a line-shaped light-receiving element that is arranged along a radial direction of the object to be processed. The light receiving element is provided with a slit plate for blocking light entering the end of the linear light receiving element. According to this, the end portion of the strip-shaped inspection light, whose detection characteristics tend to be deteriorated, is blocked by the slit plate, so that it is possible to further improve the detection accuracy of the displacement amount.

According to a fifth feature of the present invention, the deviation amount calculating section obtains coordinates of three wedge portions of the object from the detected values of the three contour position detection sensors, and calculates an arbitrary one of the three points. The center position of the object to be processed is determined from the intersection of the perpendicular bisectors of the line segments connecting the desired two points.

According to a sixth feature of the present invention, the displacement amount detecting device further includes a transport mechanism for transporting the object to be processed, and the displacement amount calculation unit includes a teaching held at a regular position of the transport mechanism. The reference origin is obtained based on the detection values of the three contour position detection sensors when the object to be processed is stopped at the position detection amount. A seventh feature of the present invention is that a plurality of processing chambers for performing a predetermined process on an object to be processed, a common transfer chamber commonly connected to a loading / unloading port of the plurality of processing chambers, A processing mechanism provided inside the chamber and capable of holding and transporting the object to be processed between the processing chambers, and a transport mechanism capable of turning and bending and extending. A standby position for temporarily holding the object to be processed is provided corresponding to the loading / unloading port of at least one of the processing chambers, and a position of a peripheral contour of the object is set corresponding to the standby position. A device for detecting position deviation is provided for detecting the position of a peripheral contour excluding the direction recognition notch of a disc-shaped object having a direction recognition notch in a peripheral portion. Three contours arranged to A displacement calculating unit for calculating a displacement between a center position of the object to be processed and a reference origin obtained based on each detection value of the three contour detection sensors; Control means is provided for obtaining a positional shift amount of the object held by the transport mechanism based on a detection value of the apparatus, and controlling the transport mechanism so as to correct the positional shift.

An eighth feature of the present invention is that a plurality of processing chambers for performing a predetermined process on an object to be processed, a common transfer chamber commonly connected to a loading / unloading port of the plurality of processing chambers, The processing object is provided in a room and held and transported between the processing chambers. In a processing system provided with a transfer mechanism capable of turning and bending and extending, a position detection chamber is connected to the common transfer chamber, and a position of a peripheral contour of the workpiece is set in the position detection chamber. A position shift detecting device for detecting the position shift is provided, and a position shift amount of the object to be processed held by the transport mechanism is obtained based on a detection value of the position shift detecting device, and the position shift is corrected. That is, a control means for controlling the transport mechanism is provided.

A ninth feature of the present invention is that the position shift detecting device detects a position shift of a disk-shaped workpiece having a direction recognition cutout portion in a peripheral portion, and the direction recognition cutout portion includes: Three contour detection sensors arranged to detect the positions of peripheral contours of the object to be removed, and the center position of the object determined based on the detection values of the three contour detection sensors. And a shift amount calculation unit for obtaining a shift amount from the reference origin.

A tenth feature of the present invention is that the displacement detection chamber is provided with support means for temporarily supporting the object to be processed. According to this, the transport mechanism in the common transport chamber can transport another workpiece in a state where the workpiece is held by the support means and is on standby.

An eleventh feature of the present invention is that an opening / closing valve that can be opened and closed so as to be able to carry and shut off the common transfer chamber is provided at the entrance of the displacement detection chamber. According to this, it is possible to perform maintenance only in the displacement detection chamber by closing the on-off valve. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic plan view showing a processing system according to the present invention.

FIG. 2 is an enlarged view showing a positional relationship between the contour detection sensor installed at the standby position and the object to be processed.

FIG. 3 is a block diagram showing a control system of the displacement detection device and the transport mechanism.

FIG. 4 is a diagram illustrating an example of the contour detection sensor.

FIG. 5 is a diagram showing a characteristic curve of the contour detection sensor.

FIG. 6 is an explanatory diagram for describing an example of a method of calculating the amount of displacement. FIG. 7 is a schematic plan view showing a processing system according to another embodiment.

FIG. 8 is a cross-sectional view showing the displacement detection chamber.

FIG. 9 is a configuration diagram showing a displacement detection chamber of a processing system according to still another embodiment of the present invention.

FIG. 10 is a schematic configuration diagram showing an example of a conventional processing system. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of a displacement detection apparatus and a processing system according to the present invention will be described in detail with reference to the accompanying drawings.

1 to 6 show a first embodiment. FIG. 1 is a schematic plan view showing a processing system according to the present invention, FIG. 2 is an enlarged view showing a positional relationship between a contour detection sensor installed at a standby position and a workpiece, and FIG. FIG. 4 is a diagram showing an example of a contour detection sensor, FIG. 5 is a diagram showing a characteristic curve of the contour detection sensor, and FIG. 6 is a diagram for explaining an example of a method of calculating a displacement amount. FIG. In these figures, the same parts as those of the conventional processing system described with reference to FIG. -As shown in the figure, the processing system 24 has a substantially hexagonal common transfer chamber 4 which can be evacuated, and the common transfer chamber 4 has gates provided at the entrance and exit respectively. A plurality of processing chambers 8A to 8D are connected via valves 6A to 6D to form a so-called class tool tool device. In each of the processing chambers 8A to 8D, there is provided a mounting table 10A to 10D provided with an electrostatic chuck on its upper surface for adsorbing and holding a semiconductor wafer W as an object to be processed by electrostatic force, for example. . Each of these processing chambers 8A to 8D may be an apparatus for performing any processing on a wafer, such as plasma or thermal CVD film formation, annealing, plasma or plasmaless etching, and oxidation diffusion. A processing chamber for performing processing and the like as needed is provided.

Further, two cassette chambers 14A and 14B for accommodating cassettes accommodating substantially disc-shaped wafers W are connected to the common transfer chamber 4 via gate valves 12A and 12B. ing. At the approximate center of the common transfer chamber 4, a transfer mechanism 16, for example, composed of an articulated arm that can rotate and bend and extend, is provided. At the tip of the arm 18 of the mechanism 16, two claw portions 18 A are provided, and the semiconductor wafer W is held by the claw portions 18 A. The paper is transferred and transferred between the processing chambers 8 to 8D and between the processing chambers 8A to 8D. In this case, it is preferable to hold the wafer W by positioning the center of the wafer W at the holding center 02 located between the two claw portions 18 A at the tip of the arm 18 so that the center of the wafer W is not displaced. . On the side of the cassette chambers 14 A and 14 B in the common transfer chamber 4, a rotary table 26 for holding and rotating a wafer and a line for detecting a positional change in the contour of the peripheral portion of the wafer W at this time are provided. A positioning mechanism 30 including a sensor 28 and the like is provided to perform positioning of the wafer W.

In the common transfer chamber 4, at least one of the processing chambers 8 A to 8 D, in the illustrated example, every other processing chamber 8 A, 8 C in the clockwise direction, a gate port, that is, a gate valve. Standby positions 32A and 32C are provided corresponding to the installation positions of 6A and 6C to temporarily stop the wafer W during transfer and wait. Although the standby positions 32 A and 32 C are shown in the illustrated example by circles of dashed lines of the same size as the wafer for convenience, they are actually only spaces through which the wafer can pass. The common transfer chamber 4 is provided with a misregistration detecting device 34, which is a feature of the present invention, and the misalignment detecting device 34 sets the center position of each of the standby positions 32A and 32C as a reference origin OA. , 0 C, and the amount of deviation of the wafer center from the reference origin OA, 0 C is determined as the amount of positional deviation as described later. More specifically, the position shift detecting device 34 includes three contour detection sensors 36-1, 3-6, 3-3 arranged corresponding to the standby positions 32A, 32C. 38-1 to 38-3, which detect the position of the peripheral contour (peripheral edge) of the wafer W.

Then, as shown in FIG. 3, each of the contour detection sensors 36-1 to 36-3 and 38-1 to 38-3 is connected to a shift amount calculation unit 40 such as a microcomputer. Thus, the above-described position shift detecting device 34 is configured. Thereby, when the wafer W is positioned at each of the standby positions 32A and 32C, the detected values of the contour detection sensors 3.6-1-3-36-3 and 38-1-3-8-3 are obtained. The amount of misalignment between the center position of the wafer and each of the reference origins OA and OC is calculated based on this. Then, as shown in FIG. 3, the shift amount output from the shift amount calculating unit 40 is, for example, a micro value. The control means 42 is input to a control means 42 composed of a computer or the like. The control means 42 controls the drive motor system 43 which is a drive source of the transport mechanism 16 so as to offset the shift amount. It has become.

Contour detection sensor that forms one set of the above three 3 6— :! 36-3 and 38-1-3-3 are arranged in exactly the same arrangement with respect to the corresponding processing chambers 8A and 8C. The contour detection sensors 36-1 to 36-3 provided at the standby position 32A corresponding to 8A will be described with reference to FIG. 2 as an example. In FIG. 2, the standby position 32 A and the peripheral contour of the wafer W are overlapped for convenience, and as shown in the figure, the three contour detection sensors 36-1 to 36-3 have the reference origin OA. Are arranged radially around the center and are spaced apart from each other substantially by 120 degrees in a plane, and also constitute a part of each sensor 36-1 to 36-3, which will be described later. The line-shaped light receiving element, for example, the line sensors 44-1 to 44-3 are arranged toward the reference origin OA so as to be substantially perpendicular to the wafer peripheral contour resting at an appropriate position.

The wafer W is generally provided with a direction-recognition notch for recognizing the direction, for example, in the case of an 8-inch wafer, an orientation flat formed by linearly cutting a part of the wafer. In the case of a 12-inch wafer, a notch is formed in which a part of the wafer is slightly cut out in a V-shape. In the case shown in FIG. 2, the case where the orientation flat OF is formed as the direction recognition notch is shown, and the orientation flat OF is located on the processing chamber 8A side. The important point is that all of the contour detection sensors 36-1 to 36-3 are arranged at positions excluding the portion of the orientation flat OF. In the illustrated example, the contour detection sensor 36-1 is arranged closest to the orientation flat OF. In this case, the deflection angle of the contour detection sensor 36-1 with respect to the direction of the processing chamber 8A is determined by the above-described orientation. It is determined in consideration of the circumferential length of the station flat 0F and the maximum deviation allowed for this wafer. For example, in the case of an 8-inch wafer, this deflection angle is set to be 22 degrees or more, and no matter how the wafer W is displaced within the maximum allowable displacement, the orientation flat OF portion is Contour detection sensor 36-1 (line sensor 4 4-1) The position is not shifted to prevent the occurrence of position error. As a matter of course, in the case of a 12-inch wafer, the notch provided in this is very short compared to the orientation flat 0 F of an 8-inch wafer, so the lower limit of the deflection angle is as follows. However, it becomes very small, for example, about 3 degrees.

Here, since the contour detection sensors 36-1 to 36-3 and 38-1 to 38-3 all have the same structure, the contour detection sensor 36-1 is used as a representative here. To explain.

As shown in FIG. 4, for example, the contour detection sensor 36-1 includes a light emitting element 46-1 supported on a ceiling portion 4 A of the common transfer chamber 4 and a light emitting element 46-1 opposed to the light emitting element 46-1. It mainly comprises the light receiving element, for example, a line sensor 441-1 supported on the bottom 4B, and the light emitting element 461-1 and the line sensor 441-1 for measuring the amount of displacement. The wafer W is positioned between them. Specifically, the light-emitting element 46-1 is attached to an upper surface of a light-transmitting window 53 made of, for example, quartz, which is provided in an opening formed in a ceiling portion 4 A through a sealing member 51 such as an O-ring. In addition, the line sensor 44-1 is provided at the opening formed in the bottom 4B with a sealing member 55 such as an O-ring, for example. Attached to. The light emitting element 46-1 illuminates the strip-shaped inspection light L 1, and is arranged with its length direction facing the reference origin O A (see FIG. 2). The line sensor 44-1, which is opposed to this, is also arranged with its length direction facing the reference origin OA as described above, and the light receiving position of the sensor body 48 that actually detects the inspection light L1, Alternatively, the position of the peripheral contour (edge portion) of the wafer W is detected according to the light shielding position by the wafer W. A slit plate 50 is provided in the vicinity of the line sensor 4411. The slit plate 50 blocks the light at both ends of the strip-shaped inspection light L1 and An elongated slit hole 52 that allows only the light at the center of the strip-shaped inspection light L1 to pass through is formed, so that the detection accuracy can be improved. The improvement of the detection accuracy will be described with reference to FIG.

FIG. 5 shows a characteristic curve of the contour detection sensor. The horizontal axis indicates the actual position of the wafer contour, and the vertical axis indicates the calculated position of the wafer contour. Also, the horizontal axis has a slit The plan view of the plate 50 and the sensor body 48 are shown in correspondence. Also, some of the scale positions in FIG. 5 are shown in FIG.

Generally, the position of the wafer contour is detected by converting the amount of light at that time into electricity by photoelectric conversion in accordance with the light receiving position (light shielding position) in the sensor body 48 and obtaining the voltage or current output at that time. As shown in Fig. 5, this characteristic becomes curved at both ends of the sensor body 48, for example, between XI and X2 or between X3 and X4. An error is likely to be included in the contour calculation position. On the other hand, since the characteristic is substantially linear in the central portion (between X 2 and X 3) of the sensor body 48, the accuracy of the calculated position of the wafer contour is very high in this portion. Therefore, in the present embodiment, the slit holes 52 are provided as described above to block the light at both ends of the strip-like inspection light L1, thereby improving the detection accuracy. Become.

Next, the operation of the present embodiment configured as described above will be described.

First, prior to performing the processing, a teaching operation is performed to teach the precise values of the standby positions 32A and 32C, which are the references for detecting the positional deviation, to the control system of the apparatus. In this operation, the electrostatic chucks of the mounting tables 10A and 10C are not used, and they are turned off, and in this state, the appropriate positions on the mounting tables 10A and 10C are used for teaching. The wafer W is placed in a state where the wafers are accurately matched, that is, in a state where there is no displacement. '

Then, the processing mechanism 8 A, 8 C and the common transfer chamber 4 are evacuated and the transfer mechanism 16 is driven to transfer each of the wafers from the mounting tables 10 A, 10 C. Stop at the detection positions, specifically, the corresponding standby positions 32A and 32C, and then each contour detection sensor 36-1 to 36-3 and 38-1 to 38 at this time. — Using the detected value of 3 as the zero reference, determine the reference origins OA and OC at this time. Thereafter, the position deviation amount of the wafer W is detected based on this value. This wafer is held at the normal position of the transfer mechanism. In addition, the reference origins OA and OC can be obtained from design data of the common transfer chamber 4 and the contour detection sensors 36-1 to 36-3, etc., but in this case, the detection accuracy of the displacement amount decreases. .

Next, a general flow of the semiconductor wafer W will be described. Either cassette The unprocessed semiconductor wafer W accommodated in a chamber, for example, 14 A, is rotated and bent by the transfer mechanism 16, so that the claw portion at the tip of the arm 18 is opened via the opened gate valve 12 A. It is held at 18 A and taken into the common transfer chamber 4. Then, by rotating the transfer mechanism 16, the wafer W is placed and held on the rotation table 26 of the positioning mechanism 30. Then, the wafer W is rotated and its edge is detected by the line sensor 28 to determine the position shift of the wafer. Next, when the wafer is held by the arm 18, the position shift is canceled. As a result, the wafer is held by the claw portion 18A in a state where the wafer is properly aligned. This aligned wafer W is directed by the transfer mechanism 16 to a predetermined processing chamber, for example, 8 A. Then, the transfer mechanism 16 is extended and the wafer W is loaded into the processing chamber 8A via the gate valve 6A which is opened, and is placed on the mounting table 1OA, and the electrostatic chuck is suctioned. Fix with force.

As described above, when the transfer of the wafer W is completed, a predetermined process is performed on the wafer W in the processing chamber 8A. When this process is completed, the transfer mechanism is extended, the arm 18 is made to enter the processing chamber 8A via the opened gate valve 6A, and the claw 18A at the end has been processed. Hold the wafer W. Then, the wafer W is taken into the common transfer chamber 4 by contracting the transfer mechanism 16. At this time, if an electrostatic chuck is provided on the mounting table 1OA, this chuck power is turned off and the charge on the wafer W is removed in advance. At this time, when the wafer W is not sufficiently neutralized and the arm 18 holds the wafer W, the wafer W jumps when it is held on the arm 18 with a positional shift. It may be getting bigger. Then, when the transfer mechanism 16 is retracted, the wafer W is temporarily stopped at the standby position 32 A, and the deviation of the center position of the wafer W from the reference origin OA of the standby position 32 A is determined by the contour detection sensor means 3. 6-1-3 c Based on the detected value of 6-3 c. When the next processing is to be performed on this wafer W, the transfer mechanism 16 is turned to transfer this wafer W to the next processing chamber. Orient to 8 B, for example. Then, when the wafer W is unloaded from the processing chamber 8 A, the operation of the transfer mechanism 16, that is, the rotation amount of the wafer W is corrected so as to correct and offset the positional deviation amount of the wafer W obtained at the standby position 32 A. And the amount of bending and elongation R is controlled, and the wafer W is placed at an appropriate position on the mounting table 10B. C Next, when a predetermined process is performed on the wafer W in the processing chamber 8B, the wafer W is taken out by the transfer mechanism 16 and is taken into the common transfer chamber 4. When the wafer W is loaded into the processing chamber 8C for the next processing, the wafer W is temporarily stopped at the standby position 32C immediately before the loading, and is made to stand by. Using the detection sensors 38-1 to 38-3, the amount of displacement of the center position of the wafer W with respect to the reference origin 0C of the standby position 32C is obtained in the same manner as described above. Then, the operation of the transport mechanism 16, that is, the rotation angle 6> and the bending / stretching amount R are controlled so as to correct and offset the position shift amount obtained here, and the wafer is placed at an appropriate position on the mounting table 10 C. W will be placed.

When the predetermined processing is completed in the processing chamber 8C and the wafer W is transferred from the processing chamber 8C to the processing chamber 8D, the wafer W is transferred by the transfer mechanism 16 to the processing chamber 8C. When the wafer W is taken out from the wafer W, the wafer W is temporarily stopped at the standby position 32 C, and the positional deviation amount of the wafer W is obtained. Then, the operation of the transport mechanism 16 is controlled so as to compensate for and offset the amount of displacement, and this is mounted on the mounting table 10D in the processing chamber 8D. The relationship at this time is the same as when the wafer W is transferred from the processing chamber 8A to the processing chamber 8B.

In this way, when the processing of the wafer W is completely completed, the completely processed wafer W is stored in, for example, a cassette in the other cassette chamber 12B. As described above, before the wafer W is loaded into each of the processing chambers 8A to 8D, the positional deviation amount is always obtained by the positioning mechanism 30 or the positional deviation detecting device 34 of the present invention. Although the description has been given of the case where the wafer taken out of the processing chamber is returned to the cassette as it is, the positional deviation amount of the wafer may be detected by the positional deviation detecting device 34, and the deviation amount may be corrected and returned to the cassette. Good. This operation is the same in the device example described later.

Next, the detection and correction of the displacement amount will be described with reference to FIGS.

As shown in FIG. 3, the contour detection sensors 36-1 to 36-3 and 38-1 to 38-3 are arranged corresponding to the standby positions 32 A and 32 C, respectively. For example, as shown in FIG. 4, for example, there is a light emitting element 461-1 and a line sensor 441-1. The coordinates (detected value) of the edge portion at that time on the line sensor 44-1 can be specified based on the position of the peripheral contour (edge portion) of the wafer W.

Then, by inputting the detection values of the respective contour detection sensors 36-1 to 36-3 or 38-1 to 38-3 to the shift amount detection unit 40, each standby position 3 2A Or the reference deviation at 32 C between the reference origin 〇A or OC and the center of the wafer is determined. Then, referring to the amount of displacement, the control means 42 outputs a command signal to the drive motor system 43 so as to correct and offset the above-described displacement, and the rotation angle 0 and the bending / stretching of the transport mechanism 16 are controlled. Control the quantity R.

Here, an example of a calculation method for obtaining the above-mentioned positional deviation amount will be described with reference to FIG. 6 taking the standby position 32A as an example. Here, the reference origin OA is set as the coordinate origin, the coordinate of the actual center WO of the wafer W is set as (X, Y), and the coordinates of each detected value of each contour detection sensor 36-1-3-1-6-3 are set as coordinates. And (x1, y1), (x2, y2) and (x3, y3).

In such a figure, the intersection of two line segments that vertically bisects each line segment connecting any two sets of points among the three points of each of the above detected values is the coordinates (Χ, Υ) Therefore, X and Υ can be expressed as the following formulas 1 and 2. Note that the reference origins OA and 〇C can be obtained by the same method.

X ( ₂ — Λ) ¾¾—) + fe— ² )} — (· ½—) fy ₃ ² —) + fe -4)} ...

2fc -bu iX ₂ -y-κ -bu iXy ₃ -yj}

Y fe - ^ bl - (2 - 2)} - - x i) b yi) + -)}

)) (2)

2 {fe- ^x i ₂ -j-, bu ₂ -¾X _3- .

Therefore, the line segment 56 connecting the origin (0, 0) and the coordinates (X, Y) is the amount of misalignment of the misaligned wafer with respect to the properly positioned wafer.

Then, as described above, the control means 42 controls the drive motor system 43 so as to offset the displacement amount 56.

Here, in the present embodiment, three contour detection sensors 36-1 to 36-3 are arranged at one standby position, for example, 32 A, and all of these sensors 36-1 to 36-3 are arranged. It is located out of the direction recognition notch, for example, the position of the orientation flat OF, so it is possible not only to accurately detect the displacement of the wafer W, but also to vary the wafer diameter due to, for example, manufacturing errors. , Or even if the wafer diameter is slightly expanded or contracted due to residual heat during heat treatment, the center position of the wafer W is accurately determined without affecting these factors, and the amount of displacement is calculated. Can be determined appropriately.

To explain this point in more detail, for example, when the center of the wafer is detected using two line sensors 20 and 22 as in the conventional apparatus shown in FIG. 10, the wafer diameter is slightly larger than the reference. In the case where the center is slightly displaced in the direction orthogonal to the arrangement direction of the sensors 20 and 22, the wafers of the appropriate size are provided to both line sensors 20 and 22 without displacement. In some cases, the same detection value is output as when it is installed, and in this case, it may be erroneously determined that there is no displacement.

On the other hand, in the case of the device of the present invention, the orientation flat OF section Since the position detection is performed at three points of the wafer contour excluding the part, if the position is misaligned as described above, it can be recognized properly and accurately. In addition, since the position shift amount is detected by using the contour detection sensors 36-1 to 36-3 and 38-1 to 38-3 fixed at a predetermined position in the common transfer chamber 4, the wafer is moved. There is no need to rotate and detect, and the amount of displacement can be detected in a short time.

Further, it is not necessary to arrange three displacement detection devices, for example, 36-1 to 36-3 at an interval of 120 degrees from each other, but in particular, as in the present embodiment, the three displacement detection devices, For example, 3 6— :! 3-6-3 are placed on the plane so as to be separated from each other by approximately 120 degrees, so that even if the position of the wafer W is displaced in any direction, the detection error can be reduced. In this case, the detection accuracy can be greatly improved.

Further, as shown in FIGS. 4 and 5, a slit plate 50 is provided near the line sensor, for example, 441-1 to block light at both ends of the strip-shaped inspection light L1 having poor characteristics. Therefore, the detection accuracy can be further improved. Further, in the above embodiment, in FIG. 1, of the processing chambers 88 to 8D, the standby positions 32A, 32C and one set of three of the processing chambers Contour detection sensor 3 6—;! However, the present invention is not limited to this, and one set of three contour detection sensors corresponding to at least one of the four processing chambers is provided. May be provided.

Also, the case where the processing path of the semiconductor wafer is sequentially processed in the clockwise direction in each of the processing chambers 8A to 8D has been described as an example, but this is merely an example.

Further, in the above embodiment, the contour detection sensors 36-1 to 36-3 and 38-; 3 to 8-3, but this is not a limitation, and a displacement detection chamber that performs displacement inspection is connected instead of some of the processing chambers 8A to 8D. You may make it. FIG. 7 is a schematic plan view showing a processing system according to such another embodiment, and FIG. 8 is a cross-sectional view showing the displacement detection chamber.

As shown in FIG. 7, here, instead of the processing chamber 8D in FIG. 1, for example, a misalignment detection chamber 60 made of aluminum is transferred via a gate valve 6D serving as an on-off valve. Connected to room 4. Note that, without providing the gate valve 6D, the inside of the common transfer chamber 4 and the inside of the misregistration detection chamber 60 may be always in communication. Then, a standby position 32E of the wafer W is set in the displacement detection chamber 60, and here, for example, the contour detection sensors 36-1 to 36-6-3 are provided at the standby position 32A. A contour detection sensor 39-1 to 39-3 having exactly the same configuration as that described above is provided. In FIG. 7, the same components as those shown in FIG. 4 are denoted by the same reference numerals. For example, each of the contour detection sensors 39-1 to 39-3 is a light emitting element 46-6. 1-4-6-3, line sensor 44-1-4-4-13 and each have a slit plate (not shown). In this case, besides the positioning mechanism 30, no other contour detection sensors 36-1-3-1-6-3 and 38-1-38-3 are provided in the common transfer chamber 4. You may. In this embodiment, except for the case where the alignment is performed by the alignment mechanism 30, for example, immediately before the wafer is loaded into each of the processing chambers 8 B and 8 C, the wafer is transferred into the displacement detection chamber 60. The wafer W may be loaded by the mechanism 16 and temporarily stopped, and the amount of displacement of the wafer W may be detected.

In the case of this embodiment, the wafer transfer speed is slightly reduced, but the same operation and effect as those of the above-described apparatus example can be exhibited. If the gate valve 6D is provided, the gate valve 6D, which is an open / close valve, is closed so that communication between the common transfer chamber 4 and the displacement detection chamber 60 is cut off. This maintenance work can be performed by opening the inside of the displacement detection chamber 60 to the atmosphere without opening the chamber 4 to the atmosphere. In this case, an N ₂ supply system and a vacuum exhaust system are independently provided for the displacement detection chamber 60.

Further, as shown in FIG. 9, a support means 70 for temporarily supporting the semiconductor wafer W carried therein may be provided in the displacement detection chamber 60 shown in FIG. The support means 70 has three support pins 72 made of, for example, quartz, which support the back surface of the wafer W. The three support pins 72 are commonly connected to an elevating port 74. The lifting rod 74 is extended downward by penetrating a rod hole 76 provided in the bottom 6 OA of the displacement detection chamber 60 by connecting the lifting rod 74 with the lifting drive mechanism 78. It can be moved up and down. Then, an elongate and contractible metal bellows is provided between the bottom 6OA and the elevating drive mechanism 78 so as to cover the periphery of the elevating rod 74. The lifting rod 74 and the support pin 72 can be moved up and down while maintaining the airtightness of the displacement detection chamber 60.

In this case, while the wafer W is supported on the support pins 72 of the support means 70, the amount of displacement of the wafer W can be detected. At this time, the transfer mechanism 16 (see FIG. 7) Can transfer other semiconductor wafers, and accordingly, the transfer efficiency can be improved and the transfer speed can be increased.

As shown in FIGS. 8 and 9, when the displacement detection chamber 60 is provided, the displacement detection device provided therein may be, for example, the position detection device of the present invention described with reference to FIGS. The present invention is not limited to the displacement detecting device, and for example, a conventional displacement detecting device as shown in FIG. 10 may be provided.

Further, in the above-described embodiment, a case has been described in which a position shift is detected when a wafer taken out of one processing chamber is processed in another processing chamber. However, in some cases, wafers taken out of a cassette are processed in one processing chamber and then only returned to the cassette without passing through another processing chamber. Such a device may not be provided with a position shift detecting device. In such an apparatus, when the processing procedure is changed to perform the continuous processing described later in the embodiment, the position detection chamber 60 is replaced with an empty boat in the common transfer chamber 4 of the existing processing system. By connecting to and adding to the above, the same effect as in the above embodiment can be easily obtained.

In each of the above embodiments, a semiconductor wafer has been described as an example of an object to be processed. However, the present invention is not limited to this as long as it has a substantially disk shape. For example, the present invention can be applied to an LCD substrate and a glass substrate. Of course.

Claims

The scope of the claims

1. A device for detecting a displacement of a disk-shaped object having a direction recognition notch in a peripheral portion,

Three contour detection sensors arranged to detect the position of the peripheral contour of the object to be processed excluding the direction recognition cutout portion;

A shift amount calculating unit for calculating a shift amount between a center position of the object to be processed and a reference origin obtained based on each detection value of the three contour detection sensors;

A position shift detecting device comprising:

2. The position according to claim 1, wherein the three contour detection sensors are arranged substantially 120 degrees apart from each other in a circumferential direction around the reference origin. Deviation detection device.

3. The installation position of the contour detection sensor is determined in consideration of the circumferential length of the direction recognition notch and the maximum deviation allowed for the object to be processed. The positional deviation detecting device according to claim 1.

4. The contour detection sensor includes a light emitting element that emits inspection light, and a linear light receiving element arranged along a radial direction of the object to be processed, and the light receiving element includes the linear light receiving element. 2. The position shift detecting device according to claim 1, further comprising a slit plate for blocking light entering the end of said light receiving element.

5. The shift amount calculation unit obtains coordinates of the three wedge portions of the object to be processed from each detection value of the three contour position detection sensors, and connects any two of the three points. 2. The position shift detecting device according to claim 1, wherein a center position of the object to be processed is obtained from an intersection of vertical bisectors of each line segment.

6. The displacement amount detecting device further includes a transport mechanism for transporting the workpiece. Prepared,

The shift amount calculating unit is configured to determine the reference origin based on the detection values of the three contour position detection sensors when the teaching target held at the regular position of the transport mechanism is stopped at the position shift amount detection position. 2. The position shift detecting device according to claim 1, wherein

7. A plurality of processing chambers for performing predetermined processing on the object to be processed,

A common transfer chamber commonly connected to the loading / unloading ports of the plurality of processing chambers,

A transfer mechanism provided in the common transfer chamber and capable of turning and bending and stretching to hold and transfer the object to be processed between the processing chambers;

In the processing system having

In the common transfer chamber, a standby position for temporarily waiting the object to be processed is provided in correspondence with a loading / unloading port of at least one of the processing chambers,

A displacement detection device for detecting a position of a peripheral contour of the object to be processed is provided in correspondence with the standby position;

This displacement detection device comprises three contour detection sensors arranged to detect the position of the peripheral contour excluding the direction recognition notch of a disc-shaped workpiece having a direction recognition notch in the periphery. And a shift amount calculating unit that calculates a shift amount between a center position of the object to be processed and a reference origin obtained based on each detection value of the three contour detection sensors,

A control unit is provided for obtaining a displacement amount of the workpiece held by the transport mechanism based on a detection value of the displacement detection device, and controlling the transport mechanism so as to correct the displacement. Processing system characterized in that:

8. The process according to claim 7, wherein the three contour detection sensors are arranged substantially 120 degrees apart from each other in a circumferential direction around the reference origin. system.

9. The installation position of the contour detection sensor is in the circumferential direction of the direction recognition notch. 8. The processing system according to claim 7, wherein the length is determined in consideration of a length of the object and a maximum deviation amount allowed for the object.

10. The contour detection sensor has a light emitting element that emits inspection light, and a linear light receiving element that is arranged along a radial direction of the object to be processed. 8. The processing system according to claim 7, wherein a slit plate for blocking light that enters the end of said light receiving element is provided.

11. The shift amount calculation unit obtains coordinates of three wedge portions of the object from the respective detection values of the three contour position detection sensors, and connects each line of any two of the three points. 8. The processing system according to claim 7, wherein a center position of the object to be processed is obtained from an intersection of a minute perpendicular bisector.

12. The displacement amount calculation unit is configured to perform the teaching based on the detection values of the three contour position detection sensors when the teaching target held at the regular position of the transport mechanism is stopped at the standby position. 8. The processing system according to claim 7, wherein the reference origin is obtained.

13. A plurality of processing chambers for performing predetermined processing on the object to be processed, and a common transfer chamber commonly connected to the loading / unloading ports of the plurality of processing chambers.

A transfer mechanism that can rotate and bend and extend to hold and transfer the object to be processed between the processing chambers provided in the common transfer chamber;

In the processing system provided with

The common transfer chamber is provided with a misalignment detection chamber connected thereto,

A displacement detection device for detecting a position of a peripheral contour of the object to be processed is provided in the displacement detection chamber,

14. The position shift detecting device detects a position shift of a disk-shaped object to be processed having a direction recognition notch in a peripheral portion,

14. The processing system according to claim 13, further comprising:

15. The processing system according to claim 13, wherein the displacement detection chamber is provided with support means for temporarily supporting the object to be processed.

16. An opening / closing valve which is openable and closable so as to be able to communicate with and block the common transfer chamber at an entrance of the displacement detection chamber. The processing system as described.