JP2005093901A - Transfer system and transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer system which can transport an object to a stage while keeping a highly aligned state of the object. <P>SOLUTION: The transfer system for transporting an object 1 having a plurality of positional marks comprises a transfer arm 10 having a means 13 for holding the object 1 to rotate and transport the object in its held state, a stage 20 for accepting and holding the object, a detection means for detecting the plurality of positional marks of the object 1 held in the transfer arm and detecting shifts from a reference position and a reference orientation of the object, and a means for controlling the orientation of the object and the position of the stage when the object is accepted at the stage 20 according to the detected shifts so that the stage 20 accepts the object at a predetermined position and orientation and for controlling the object and the stage in such a manner that the object is always held to at least one of the holding means 13 and the stage 20 upon the transfer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a transport system and a transport method for transporting an object such as a wafer, and more particularly to a transport system and a transport method for accurately maintaining and delivering an aligned state after the object is precisely aligned.

  A conveyance system for conveying various objects is widely used. Various transport methods are used depending on the object to be transported. One of them is a chuck mechanism for holding (chucking) an object at the tip of the transport arm. After chucking the object at a predetermined receiving position, the transport arm is A transport system that rotates and transports an object to a stage at a predetermined delivery position is widely used in various manufacturing processes. The present invention relates to a transport system and a transport method using such a transport arm. In particular, in a semiconductor manufacturing apparatus, the transfer arm as described above is often used to transfer a wafer (object), and the stage is required to have very high positional accuracy and azimuth accuracy, and high throughput is required. Therefore, it is required that the conveyance time is short. Here, an explanation will be given by taking a transfer system used in a semiconductor manufacturing apparatus as an example.

  Objects such as wafers and masks transported to the stage are used for various purposes and are subjected to various types of processing. For this purpose, the position and rotational position (orientation) of the transported object are detected. Needs to be adjusted so as to have a desired position and orientation. Therefore, the stage can move at least in the two axial directions of the X axis and the Y axis, and has a rotation mechanism that rotates the mounting surface.

The stage needs to be provided with various functions, and if a rotation mechanism is further provided on the stage, the configuration becomes complicated, resulting in a problem that it is very expensive. Japanese Patent Laid-Open No. 10-64978 discloses that a rotation device is provided separately, an object (measurement object) is placed on the rotation device, the position and orientation of the measurement object are detected, and the orientation is adjusted by rotation. An alignment apparatus is disclosed in which a transfer arm receives a measurement object, adjusts a receiving position of a stage in accordance with the detected position of the measurement object, and receives the measurement object from the transfer arm.
Furthermore, this patent document discloses that a mark on an object to be measured (object) placed on a rotating device is detected to detect the position and orientation of the object to be measured.

  A stage used in a semiconductor manufacturing process is required to have a very precise position and rotational accuracy. Mechanisms with precise rotational accuracy over a wide rotational range are very expensive. Therefore, a combination of a precision rotation mechanism with a very high accuracy but a narrow rotation range and a coarse rotation mechanism with a large rotation range but a relatively low rotation accuracy is performed. Here, if the position and orientation of the object to be conveyed are adjusted in advance and are within a predetermined error range, the coarse motion rotation mechanism can be omitted, and the cost of the stage can be reduced accordingly. Also, if the error in the position and orientation of the object being conveyed is large, the time required to accurately detect and correct the position and orientation of the object will increase, but the position and orientation of the object to be conveyed will be adjusted in advance. If it is within the predetermined error range, the time required for this can be shortened and the throughput can be improved. In any case, it is desirable that the object is conveyed to the stage in an aligned state.

  According to the configuration disclosed in Japanese Patent Laid-Open No. 10-64978, it is possible to transport the object to be measured to the stage in an aligned state, but it is necessary to provide a separate rotating device, and the space is increased accordingly. Therefore, there is a problem that the cost of the entire system becomes high. In order to solve such a problem, Japanese Patent Laid-Open Nos. 2002-270672 and 10-335410 use a multi-axis (three-axis) rotating arm and hold an object (wafer) to be transferred. A configuration is disclosed in which the center position of the wafer and the orientation flat (orientation flat) are detected and delivered while the wafer is aligned.

Japanese Patent Laid-Open No. 10-64978 (overall) JP 2002-270672 A (Overall) JP-A-10-335410 (Overall)

In recent years, along with the need for higher integration of semiconductor integrated circuits, further miniaturization of circuit patterns has been demanded, and further improvements in stage position accuracy and azimuth accuracy have been demanded accordingly. A decrease in throughput and an increase in cost are not acceptable, and further improvements in throughput and cost are required.
As described above, in order to improve the position accuracy and azimuth accuracy of the stage without lowering the throughput and increasing the cost, it is necessary to improve the alignment accuracy of the object at the stage where the object is transported to the stage. is there.

  What is important in improving the alignment accuracy of the object conveyed to the stage is that the alignment accuracy cannot be higher than the rotation accuracy of the conveyance arm including the shaft shake. In the configuration disclosed in the above Japanese Patent Laid-Open No. 2002-270672 and Japanese Patent Laid-Open No. 10-335410, a multi-axis (three-axis) transfer arm is used. There is a problem that it is difficult to obtain high position accuracy and azimuth accuracy because the error of the axis synergistically affects. Therefore, when using a multi-axis transfer arm as disclosed in the above-mentioned patent document, the center and orientation flat of the wafer (object) can be easily detected, but it is difficult to deliver the wafer aligned with sufficiently high accuracy. There is a problem.

  In a wafer exposure apparatus and inspection apparatus, sufficient positioning processing is difficult with the detection accuracy of the center position and orientation flat position of the wafer, and it is necessary to perform positioning processing by detecting a position mark formed on the wafer. Therefore, the configurations disclosed in Japanese Patent Application Laid-Open Nos. 2002-270672 and 10-335410 are configurations for performing alignment with less precision and cannot be used for performing higher-precision alignment.

  On the other hand, in the configuration disclosed in Japanese Patent Laid-Open No. 10-64978, a uniaxial transfer arm is used, and the error due to the transfer arm is very small compared to the case of multi-axis. In this configuration, position marks on the object to be measured are detected to detect misalignment and azimuth misalignment, enabling positioning with much higher accuracy than when detecting the center position and orientation flat of the wafer. is there.

  However, Japanese Patent Laid-Open No. 10-64978 only describes that a measurement object whose orientation is adjusted by a rotating device is transported to a stage using a single-axis transport arm, and describes a specific operation and configuration. Not. In view of the known technology, it is considered that a means for chucking the object to be measured is provided at the tip of the single-axis transport arm, but there is no description about the presence or absence of the chuck mechanism of the rotating device. Further, even if each of the rotating device, the one-axis transport arm, and the stage has a chuck mechanism, the operation of the chuck mechanism at the time of delivery is not described.

  In order to maintain the position and orientation of the detected or corrected object, it is necessary that the object is chucked by any device. When an object is transferred from one device to the other device, if one device releases the chuck and the other device chucks, the object is temporarily not chucked by any device, and the other device When chucking, positional deviation and azimuth deviation occur. Although this deviation is considered not to be so great, it cannot be ignored when performing highly accurate alignment. Even if the object is aligned with high accuracy, if a state occurs in which the object is not chucked at the time of delivery to the stage, a deviation occurs when the stage chucks the object, thereby lowering the alignment accuracy.

As described above, Japanese Patent Application Laid-Open No. 10-64978 does not describe the chuck mechanism and does not describe the operation of the chuck mechanism when delivering the object to be measured. Furthermore, Japanese Patent Application Laid-Open No. 2002-270672 describes that the tip corresponding to the tip of the triaxial transfer arm and the hand corresponding to the stage have a chuck mechanism, but does not describe the operation of the chuck mechanism at the time of wafer delivery. Absent. Furthermore, Japanese Patent Laid-Open No. 10-335410 describes that the tip of the three-axis transfer arm can hold the wafer, but does not describe the chuck mechanism of the measurement table. The operation at the time of delivery of the wafer of the measurement table is not described. Furthermore, Japanese Patent Laid-Open No. 10-335410 does not describe the stage to which the aligned wafer is transferred, and does not describe the delivery of the wafer to the stage.
As described above, none of the above-mentioned patent documents describes a chucking operation when an object is delivered.

  An object of the present invention is to realize a high-throughput and low-cost conveyance system and a conveyance method capable of conveying an object aligned with high accuracy while maintaining a highly accurate alignment state.

  In order to achieve the above object, the transport system and the transport method of the present invention use a rotary transfer arm having a holding means for fixing and holding an object to be transferred, and a plurality of position marks of the object held by the rotary transfer arm. Detecting the deviation from the reference position and the reference azimuth, and controlling the azimuth of the object and the position of the stage according to the detected deviation so that the stage receives the object at the predetermined position and azimuth. At the same time, the object is controlled so that the object is always held by at least one of the holding means of the transfer arm and the stage at the time of delivery.

  That is, the transport system of the present invention is a transport system that transports an object having a plurality of position marks on the surface, and has a holding means that can rotate about a rotation axis and holds the object. Detecting a plurality of position marks of the object held on the transfer arm; a transfer arm that rotates and conveys the object in a held state; a stage that is movable in at least two axial directions; An object position deviation detecting means for detecting a deviation of the object held by the transfer arm from a reference position and a reference direction, and the object position deviation detection so that the stage receives the object at a predetermined position and direction. The orientation of the object at the time of delivery and the position of the stage are controlled according to the detected deviation of the means, and the object is Always at least one of the stage and lifting means, characterized in that it comprises a control means for controlling so as to maintain.

  According to the present invention, since the deviation from the reference position and the reference azimuth is detected by detecting a plurality of position marks of the object held on the rotary transfer arm, the positional deviation and the azimuth deviation of the object can be detected with high accuracy. Since the stage receives the object at a predetermined position and orientation, the orientation of the object and the position of the stage at the time of delivery are controlled according to the detected deviation, so that the alignment can be performed between the rotary transfer arm and the stage. Further, since the object is controlled so that it is always held by at least one of the holding means of the transfer arm and the stage at the time of delivery, the object aligned with high accuracy can be delivered with the same accuracy.

  In order to achieve high transfer accuracy, it is desirable to use a single-axis rotary arm as the transfer arm. In that case, the rotation position of the single-axis rotary arm is corrected by the detected deviation of the orientation of the object, and the object at the time of delivery is transferred. The azimuth is corrected, and the position of the stage is corrected by an amount obtained by adding the amount of displacement due to the correction of the rotational position of the uniaxial rotating arm to the detected displacement of the object. As a result, the object can be transferred to the stage in an aligned state in which both the positional deviation and the azimuth deviation of the object are corrected using a stage without a single-axis rotating arm and a rotating mechanism.

  FIG. 1 is a diagram for explaining this operation. As shown in the figure, a holding means 13 for fixing and holding an object (wafer or mask) 1 is provided on a tip member 12 of a uniaxial rotating arm 10 that rotates about a shaft 11. In this transport system, the object 1 is held by the holding means 13, the uniaxial rotating arm 10 is rotated and transferred to the stage 20. With the object 1 held, a position mark (not shown) on the object 1 is detected, and deviations ΔX and ΔY from the reference position and deviation Δθ from the reference azimuth of the held object 1 are detected. Then, the uniaxial rotating arm 10 is rotated to a position shifted by Δθ from the normal delivery position. As a result, the orientation of the object 1 with respect to the stage 20 becomes a normal orientation. Then, the object 1 is moved to the normal delivery position by receiving the object 1 by moving the stage 20 from the normal delivery position by adding the deviation caused by shifting the rotational position of the shaft rotary arm 10 by Δθ to ΔX and ΔY. It is held in a predetermined orientation at 20 predetermined positions.

  In order to achieve high transfer accuracy, the transfer arm is required to use a single-axis rotary arm. However, a rotation mechanism that rotates the object by a small amount is provided at the tip of the single-axis rotary arm to detect the orientation of the detected object. The rotational position of the rotating mechanism may be corrected by the amount of deviation to correct the orientation of the object at the time of delivery. In this case, it is necessary to correct the position of the stage by an amount obtained by adding the amount of displacement due to the correction of the rotational position of the rotation mechanism to the detected displacement of the object.

  By providing a rotation mechanism, the conveyance accuracy by the conveyance arm is lower than when only a single-axis rotation arm is used, but the amount of rotation of the rotation mechanism is small, so even with two axes, the decrease in accuracy is small. Since the rotation amount is small, a very high-precision rotation mechanism can be used, so that a decrease in conveyance accuracy can be very small.

In most cases, the position mark on the surface of the object is required to be detected without contact, and in that case, an optical image of the position mark is captured by a photodetector. Further, in order to detect the positional deviation and the azimuth deviation of the object held on the transfer arm with high accuracy, it is desirable to detect the positions of two or more position marks provided away from the object surface. The light detector has a limited field of view, and in order to detect two or more position marks separated by a single light detector, when the object is rotated by the transfer arm, a plurality of position marks are detected by this light. Position it so that it passes through the field of view of the vessel. In this case, the transport arm is temporarily stopped at a position where the position mark falls within the visual field of the photodetector. Further, when such arrangement is difficult, a moving means for moving the photodetector may be provided so that the photodetector is moved so that each position mark falls within the field of view of the photodetector.
Furthermore, a plurality of photodetectors may be provided to detect a plurality of position marks.

Although it is necessary to use a transfer arm that can control the rotational position with high precision, even in such a case, arm rotation position detection means for detecting the rotation position of the transfer arm is further provided so that each photodetector It is desirable to detect the rotational position of the transfer arm when detecting the position of the position mark, and correct so as to eliminate the influence of the error in the rotational position of the transfer arm. Further, it is desirable to detect a rotational position of the transfer arm when delivering an object to the stage and perform feedback control to eliminate a deviation due to an error in the rotation position of the transfer arm.
In order to detect the rotation position of the transfer arm, a scale indicating the rotation position is provided on the transfer arm, and the scale is detected when the position of the position mark is detected by the photodetector.

  According to the present invention, it is possible to transport an object aligned with high accuracy to a stage with a simple configuration while maintaining a highly accurate alignment state. As a result, the configuration of the stage can be simplified and the cost can be reduced, and since the alignment of the conveyed object is highly accurate, the time required for the alignment operation on the stage can be shortened and the throughput can be improved.

  2 and 3 are views showing the overall configuration of the transport system according to the first embodiment of the present invention, FIG. 2 is a top view, and FIG. 3 is a side sectional view. This transfer system transfers the wafer 1 prepared in the atmospheric pressure to a receiving unit 30 provided in the load lock chamber, changes the load lock chamber from the atmospheric pressure state to the vacuum state, and then transfers the load lock chamber to the load lock chamber. The system opens the gate and transports it from the receiving unit 30 to the stage 20 in the exposure chamber, and is required to hold the wafer 1 in a state of being accurately aligned with the stage 20. In FIG. 2, the solid transfer arm indicates a state where the wafer 1 in the receiving unit 30 is held, and the broken transfer arm indicates a state where the wafer 1 is transferred to the stage 30. The stage 20 can be translated in three axes and rotated around the three axes, but the range of each rotation is narrow, and the wafer to be transferred is aligned with high accuracy so that the orientation is within this range. It is necessary to be. In addition, if alignment is performed with high accuracy, a considerable part of the alignment that has been performed on the conventional stage can be omitted, thereby improving throughput.

  The wafer 1 received by the receiving unit 30 is aligned with a certain degree of accuracy based on the outer diameter and notch (or orientation flat) of the wafer, and is fixed to the receiving unit 30 in the aligned state. As a result, the field of view of the CCD camera for detecting the position mark on the wafer 1 can be narrowed, so that the position mark can be detected with high accuracy, the time required for detecting the position mark can be shortened, and further from the reference orientation of the wafer 1. Since the deviation is small, the rotation range of the arm and the movement range of the stage can be reduced.

  As shown in FIG. 2, the transfer arm 10 has an L shape, and one end is locked to the rotating shaft 11. The rotation axis 11 can control the rotation angle with very high resolution, and the transfer arm 10 can control the rotation position with high accuracy. Further, the rotary shaft 11 can move in the axial direction, and the transfer arm 10 can also move in the vertical direction accordingly. A tip member 12 for holding the circular wafer 1 is provided at the other end of the transfer arm 10, and holding members 13 are provided at three locations of the tip member 12. A scale 15 for detecting the rotational position of the transfer arm with high accuracy is provided on the transfer arm 10.

Reference numeral 41 denotes a TV camera for position mark detection that detects a position mark formed on the wafer 1. When the wafer 1 is held and rotated by the transfer arm 10, two position marks on the wafer 1 are displayed. It is installed at a position that passes through the visual field of the TV camera 41 for position mark detection.
Reference numerals 45 and 46 are scale detection TV cameras for detecting the scale 15, and the scale detection TV camera 45 detects the scale 15 when the position mark detection TV camera 41 detects two position marks. Is installed in the field of view of the TV camera 45 for scale detection, and a scale 15 having a certain length is used so that this is possible.

The TV camera 46 for scale detection is used when the transfer arm 10 transfers the wafer 1 to the stage 20, that is, when the wafer, the transfer arm and the scale are positioned as indicated by 1 ', 10' and 15 'in the drawing. Are installed in the field of view of the TV camera 46 for scale detection.
As shown in FIG. 3, the above three TV cameras are provided outside the load lock chamber and detect the scale through an observation window (not shown) provided in the load lock chamber casing 5. It is configured.
In addition, a control unit configured by a computer that performs control of each unit and performs detection processing and correction calculation of a position mark and a scale is provided. Since the configuration for this is widely known, detailed description thereof is omitted here.

FIG. 4 is a diagram for explaining the shape of the tip member 12, the holding member 13, the stage 20 and the receiving portion 30, and the operation when delivering the wafer. As shown in FIG. 4A, the tip member 12 has a shape corresponding to half of the circular wafer 1, and holding members 13 are provided at three locations. Here, the holding member 13 uses an electrostatic chuck for use in a vacuum state, but a vacuum suction mechanism can also be used as long as it is a transfer system used in atmospheric pressure.
Although the stage 20 and the receiving unit 30 are actually different in shape, the structures for the wafer transfer operation are basically the same, and are shown in common. As shown in FIG. 4B, a portion 24 on the right side of the upper surface of the stage 20 and the receiving unit 30 is cut out at a portion 24 outside the radius slightly smaller than the radius of the wafer 1. The holding member 13 contacts the lower surface of the wafer 1 at the notched portion 24. An electrostatic chuck is provided in the circular portion 22 having a radius slightly smaller than the cut-out portion.

  When the holding member 13 receives the wafer 1 electrostatically chucked by the receiving unit 30, as shown in FIG. 4C, the transfer arm is rotated to the right side, and the tip member 12 is positioned on the right side of the wafer 1. Then, even if it is lowered, the holding member 13 moves to a position where it does not come into contact with the wafer, and the holding member 13 is lowered to a position once below the wafer. Thereafter, after the transfer arm is rotated to the left as shown in FIG. 4A, the transfer arm 10 is raised and stopped at a position where the holding member 13 contacts the lower surface of the wafer 1. Then, the electrostatic chuck of the holding member 13 is activated to chuck the wafer 1 on the holding member 13, and then the electrostatic chuck of the receiving unit 30 is released. Thereafter, the holding member 13 is raised to a position where it does not come into contact with the receiving portion 30 even if the transport arm 10 is rotated.

  When the wafer 1 held on the holding member 13 is transferred to the stage 20, the transfer arm is rotated to the transfer position and lowered until the wafer 1 contacts the stage 20. Then, after the electrostatic chuck of the stage 20 is operated to chuck the wafer 1 on the stage 20, the electrostatic chuck of the holding member 13 is released. Thereafter, the transfer arm is lowered slightly so that the holding member 13 does not contact the back surface of the wafer 1, and then the transfer arm is rotated in the reverse direction. This is the operation at the time of wafer transfer.

FIG. 6 is a flowchart for explaining the operation even when the wafer 1 held by the receiving unit 30 is transferred to the stage 20 in the first embodiment, and FIG. 6 is a diagram showing a state change during the operation.
In step 101, the wafer 1 held by the receiving unit 30 is held on the holding member 13 of the transfer arm 10 by the procedure described with reference to FIG. FIG. 6A shows a state in which the transfer arm 10 has received the wafer 1.
In step 102, the transfer arm 10 is rotated to a position where the first position mark provided on the wafer 1 falls within the field of view of the position mark detection TV camera 41. FIG. 6B shows this state, and the scale 15 is within the field of view of the TV camera 45 for scale detection as shown.

In step 103, the position of the first position mark in the camera coordinates of the position mark detection TV camera 41 is detected. This detection is performed using a known image processing technique.
Further, in step 104, the scale detection TV camera 45 detects the scale 15, detects the scale 15 in the camera coordinates of the scale detection TV camera 45, and obtains the angle of the transfer arm.

  The position of the first position mark in the camera coordinates of the detected position mark detection TV camera 41 is coordinate-converted to calculate the position of the first position mark in the global coordinates of the transport system. As described above, the rotation angle of the rotary shaft 11 can be controlled with very high resolution, but in order to further reduce the influence of the error, correction is made here at the position of the scale 15 detected by the TV camera 45 for scale detection. I do. However, if the rotational position accuracy of the rotary shaft 11 is sufficient, correction using the position of the scale 15 detected by the scale detection TV camera 45 is not necessary.

  In step 105, the transfer arm 10 is rotated to a position where the second position mark provided on the wafer 1 falls within the field of view of the TV camera 41 for position mark detection. FIG. 6C shows this state, and the scale 15 is within the field of view of the TV camera 45 for scale detection as shown. Since the scale 15 needs to enter the field of view of the TV camera 45 for scale detection in both the states (B) and (C) of FIG. 6, the scale 15 has a length as illustrated.

In step 106, the position mark detection TV camera 41 detects the position of the second position mark. In step 107, the scale detection TV camera 45 detects the scale 15 and detects the angle of the transfer arm.
As described above, the positions of the first and second position marks and the angle of the transport arm when they are detected are detected.

  In step 108, based on these detection values, deviations ΔX and ΔY from the reference position of the wafer 1 held on the transfer arm and deviation Δθ from the reference direction are calculated, and the method described in FIG. 1 is used. , Δθ is a correction value of the rotation angle of the transfer arm when the wafer 1 is transferred to the stage 20, and further, a position shift amount obtained by correcting the rotation angle of the transfer arm by Δθ is added to ΔX and ΔY, and at the transfer position. A correction value for the position of the stage 20 is calculated.

In step 109, the stage 20 and the transfer arm 10 are moved from the standard delivery position to the delivery position corrected by the above correction value. FIG. 6D shows this state.
If the rotational position accuracy of the rotating shaft 11 is sufficient, it is possible to proceed to step 111 and transfer the wafer 1 to the stage 20 as it is, but here, in step 110, the TV camera 46 for scale detection uses the scale 15 And the feedback control is performed so that the rotation angle of the delivery position corrected by the transfer arm 10 is performed, and the rotation position of the transfer arm 10 is accurately controlled.
In step 111, the wafer 1 is delivered to the stage 20 using the method described in FIG.

  As described above, since the transfer system of the first embodiment detects a plurality of position marks provided on the wafer held by the transfer arm, it is possible to detect wafer positional deviation and azimuth deviation with high accuracy. When the wafer is transferred from the transfer arm to the stage, the wafer is transferred while being held on either the transfer arm or the stage, and the rotation position of the transfer arm and the position of the stage are corrected by the detected positional deviation and azimuth deviation. Since it is delivered, the detected deviation can be accurately corrected and delivered. Further, since the transfer arm is a single-axis rotary arm, it is possible to control the rotational position with high accuracy and to perform correction by reading the scale, so that high-accuracy conveyance is possible. As a result, the time required for correcting the position and orientation of the wafer on the stage after receiving the wafer can be shortened, and the above processing in the transfer system may be performed while the processing using the stage is being performed. Throughput in processing using is improved.

  In addition, since the transfer system of the first embodiment uses a uniaxial rotary transfer arm, the cost is low, the stage rotation mechanism can be simply configured, and there is no need to provide a separate wafer rotation device. The whole can be made low-cost.

  FIG. 7 is a view showing the structure of the tip member 12 of the transfer arm 10 according to the second embodiment of the present invention. Other parts of the transport system of the second embodiment are the same as those of the first embodiment. As shown in FIG. 7, the tip member 12 is rotatably locked to a shaft 51 provided on the transport arm 10. A piezo element 53 is provided between a portion 14 of the tip member 12 and a member 52 provided on the transfer arm 10, and the tip member 12 rotates a small amount around the shaft 51 by driving the piezo element 53. . Since the rotation mechanism of the tip member 12 uses the piezo element 53, the rotation range is very small, but the rotation accuracy can be very high.

  The operation when the wafer is transferred from the receiving unit 30 to the stage 20 in the transfer system of the second embodiment is similar to the operation of the first embodiment described with reference to FIG. 5, and only steps 108 and 109 are different. In the transfer system of the second embodiment, after performing the operations from Step 101 to Step 107, the tip member 12 is rotated by the wafer orientation deviation Δθ detected by the rotation mechanism. Then, a correction amount of the delivery position of the stage is calculated by adding a deviation caused by rotating the tip member 12 by Δθ to the detected ΔX and ΔY. Then, the stage is moved to the delivery position corrected by the correction amount, and the transfer arm is rotated by feedback control so as to reach the reference rotation position, and then the wafer is delivered.

  In the first embodiment, the first and second position marks are set so as to sequentially pass through the field of view of the TV camera 41 for position mark detection when the transport arm is rotated. It is also possible to detect simultaneously with a TV camera for detection. The third embodiment of the present invention uses two position mark detection TV cameras. Other configurations in the third embodiment are the same as those in the first embodiment.

  FIG. 8 is a diagram showing the arrangement of the transfer arm, the position mark detection TV camera, and the like in the transfer system of the third embodiment of the present invention. As shown by broken lines in the figure, when the first and second position mark detecting TV cameras 41 and 42 are rotated by the transfer arm 10, the first and second position marks on the wafer 1 are the first and second position marks. It arrange | positions so that it may enter into the visual field of 2nd position mark detection TV cameras 41 and 42 simultaneously. At this time, the scale 15 enters the field of view of the TV camera 45 for scale detection. Then, the positions of the first and second position marks are detected at the same time, and at the same time, the scale 15 is detected and the rotation position of the transfer arm 10 is detected. That is, in the third embodiment, steps 105 to 107 of the first embodiment are executed simultaneously with steps 102 to 104. Since the scale detection TV camera 45 only needs to detect the scale 15 at this time, the scale 15 need not be as large as the first embodiment.

  FIG. 9 is a diagram showing the arrangement of the transfer arm, the position mark detection TV camera, and the like in the transfer system of the fourth embodiment of the present invention. In the transport system of the fourth embodiment, instead of providing two position mark detection TV cameras in the third embodiment, the position mark detection TV camera 41 is replaced with the second position mark detection TV camera 42 of FIG. A moving mechanism 43 that moves to the position 41 ′ is provided, and the first position mark is detected by the TV camera 41 for position mark detection at the position indicated by the reference numeral 41, and then moved to the position 41 ′ by the moving mechanism 43. Detect position marks. Others are the same as the third embodiment.

Although the embodiments of the present invention have been described above, it goes without saying that various modifications are possible. For example, in the above-described embodiment, an example in which a wafer is transferred is shown, but the present invention can be applied to any object such as a reticle or a mask.
In the above embodiment, the back surface of the wafer is electrostatically chucked by the holding member. However, for example, a mechanism that clamps and holds the edge of the wafer can be used.

  As described above, according to the present invention, it is possible to align an object with high accuracy and transport it to the stage while maintaining the aligned state, thereby shortening the alignment time on the stage. As a result, the throughput of the entire apparatus in which this transport system is used can be improved.

In the conveyance system and method of this invention, it is a figure explaining the principle which correct | amends and delivers a position and an azimuth | direction. It is a top view which shows the whole structure of the conveyance system of 1st Example of this invention. 1 is a side sectional view showing an overall configuration of a transport system according to a first embodiment of the present invention. It is a figure which shows the structure of the front-end | tip member and holding member of a conveyance arm of the conveyance system of 1st Example, and a stage or a receiving part. It is a flowchart which shows the conveyance operation in 1st Example. It is a figure explaining conveyance operation in the 1st example. It is a figure which shows the front-end | tip member of the conveyance arm of 2nd Example of this invention. It is a figure which shows arrangement | positioning of the conveyance arm of 3rd Example of this invention, a position mark, and the TV camera for scale detection. It is a figure which shows arrangement | positioning of the conveyance arm of 4th Example of this invention, a position mark, and the TV camera for scale detection.

Explanation of symbols

1 ... wafer (object)
DESCRIPTION OF SYMBOLS 10 ... Transfer arm 11 ... Rotary shaft 12 ... End member 13 ... Holding member 20 ... Stage 30 ... Receiving part

Claims (14)

A transport system for transporting an object having a plurality of position marks on a surface,
A transfer arm that is rotatable about a rotation axis, has holding means for holding the object, and rotates and conveys the object while holding the object;
A stage that is movable in at least two axes and receives and holds the object;
Object position deviation detecting means for detecting the plurality of position marks of the object held by the transfer arm and detecting deviations from the reference position and reference direction of the object held by the transfer arm;
The azimuth of the object and the position of the stage at the time of delivery are controlled according to the deviation detected by the object position deviation detection means so that the stage receives the object at a predetermined position and azimuth. A transport system comprising: control means for controlling an object to be always held by at least one of the holding means and the stage of the transport arm. The transfer arm is a uniaxial rotating arm,
The control means corrects the orientation of the object at the time of delivery by correcting the rotational position of the one-axis rotary arm by the amount of deviation of the orientation of the object detected by the object position deviation detection means. 2. The transport system according to claim 1, wherein control is performed so as to correct the position of the stage by an amount obtained by adding a positional shift amount by correcting the rotational position of the one-axis rotary arm to the positional shift of the object detected by the shift detection unit. . The transfer arm is composed of a uniaxial rotating arm and a rotating mechanism that rotates a small amount of the held object provided at the tip of the uniaxial rotating arm,
The control means corrects the orientation of the object at the time of delivery by correcting the rotational position of the rotation mechanism by an amount of deviation of the orientation of the object detected by the object position deviation detection means, and the object position deviation The transport system according to claim 1, wherein the position of the stage is controlled to be corrected by an amount obtained by adding a positional shift amount obtained by correcting the rotational position of the rotating mechanism to the positional shift of the object detected by the detection unit. The object position deviation detecting means is a photodetector that captures an optical image of the plurality of position marks on the surface of the object, and the plurality of position marks are detected by the light when the object is rotated by the transport arm. It is arranged to pass through the detection range of the instrument,
The transport system according to claim 1, wherein the photodetector detects the position of each position mark in a state where the transport arm is rotated so that each position mark is positioned within a detection range of the photodetector. The object position deviation detection means is a plurality of photodetectors that capture optical images of the plurality of position marks on the surface of the object,
The plurality of photodetectors are arranged such that when the object is rotated by the transfer arm, the plurality of position marks pass through detection ranges of the corresponding plurality of photodetectors,
The transport system according to claim 1, wherein each photodetector detects the position of each position mark when each position mark passes through a detection range of the photodetector. The object position deviation detecting means includes a photodetector that captures an optical image of the plurality of position marks on the surface of the object, and a moving means that moves the photodetector.
The transport system according to claim 1, wherein the photodetector detects a position of each position mark when each position mark is within a detection range of the photodetector. Arm rotation position detection means for detecting the rotation position of the transfer arm when the light detector detects the position of each position mark;
The object position deviation detection means is based on the positions of the plurality of position marks detected by the photodetector and the rotation position of the transfer arm detected by the arm rotation position detection means from the reference position and reference direction of the object. The conveyance system according to any one of claims 3 to 6, wherein a deviation is detected. Another arm rotation position detecting means for detecting the rotation position of the transfer arm in the vicinity where the transfer arm is positioned when the object is delivered to the stage;
8. The feedback control according to claim 7, wherein the control unit feedback-controls the rotation position of the transfer arm when the object is delivered to the stage from the rotation position of the transfer arm detected by the another arm rotation position detection unit. Conveying system.   The arm rotation position detection means includes a scale indicating a rotation position provided on the transfer arm, and a rotation position detector arranged to detect the scale when the light detector detects the position of each position mark. A transport system according to claim 7 or 8. A method for conveying an object having a plurality of position marks on a surface,
In a state where the object is held on the transfer arm, the plurality of position marks are detected, and a deviation from a reference position and a reference direction of the object held on the transfer arm is detected,
Correcting the orientation of the object and the position of the stage according to the detected deviation so that the stage receives the object at a predetermined position and orientation when delivering the object to the stage;
Transferring the object so that the object is always held by at least one of the transfer arm and the stage. The transfer arm is a uniaxial rotating arm,
By correcting the rotational position of the one-axis rotary arm by the detected deviation of the orientation of the object, the orientation of the object at the time of delivery is corrected,
The transport method according to claim 10, wherein the position of the stage is corrected by an amount obtained by adding a positional shift amount obtained by correcting the rotational position of the one-axis rotary arm to the detected positional shift of the object. The transfer arm is composed of a uniaxial rotating arm and a rotating mechanism that rotates a small amount of the held object provided at the tip of the uniaxial rotating arm,
By correcting the rotation position of the rotation mechanism by the detected deviation of the orientation of the object, the orientation of the object at the time of delivery is corrected,
The transport method according to claim 10, wherein the position of the stage is corrected by an amount obtained by adding a positional shift amount obtained by correcting the rotational position of the rotating mechanism to the detected positional shift of the object. When detecting the position of the plurality of position marks, further detecting the rotational position of the transfer arm,
The transport method according to claim 11 or 12, wherein a deviation from a reference position and a reference direction of the object is detected from the detected positions of the plurality of position marks and the rotation position of the transport arm. Further detecting the rotational position of the transfer arm in the vicinity where the transfer arm is located when delivering the object to the stage,
The transfer method according to claim 13, wherein the rotation position of the transfer arm when the object is transferred to the stage is corrected by feedback control from the rotation position of the transfer arm when the transfer is performed.

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