JP5847661B2 - Substrate position adjusting device, substrate position adjusting method, program, and computer storage medium - Google Patents

Description

  The present invention relates to a position adjusting device for adjusting the position of a substrate, a method for adjusting the position of a substrate using the position adjusting device, a program, and a computer storage medium.

  For example, in the photolithography process in the manufacture of semiconductor devices, for example, a resist coating process for forming a resist film by applying a resist solution on a semiconductor wafer (hereinafter referred to as “wafer”), and selectively exposing the peripheral portion of the resist film Peripheral exposure processing, exposure processing for exposing a predetermined pattern on the resist film exposed at the peripheral portion, development processing for developing the exposed resist film, etc. are sequentially performed to form a predetermined resist pattern on the wafer. The

  When the photolithography process is performed as described above, a plurality of processes are performed on a predetermined position of the wafer. Therefore, a so-called alignment operation is performed as alignment of the wafer so that the processing is performed at the same position of the wafer for each processing.

  In wafer alignment, as disclosed in, for example, Patent Document 1, a mechanism for holding and rotating a wafer is used. Then, after aligning the center position of the wafer with the center position of the mechanism for holding the wafer, the position of the wafer is adjusted by detecting the notch formed in the wafer in the position in the rotation direction of the wafer.

JP 2010-165706 A

  By the way, when the center position of the mechanism for holding the wafer is aligned with the center position of the wafer, for example, as shown in FIG. Irradiation is performed vertically on the outer peripheral edge of the held wafer W. Then, the light irradiated onto the wafer W is detected by the line sensor 203 disposed vertically below the wafer W while rotating the wafer W held on the rotation holding mechanism 202 at a low speed. Specifically, if the center position of the wafer W coincides with the center position of the rotation holding mechanism 200, the end of the light blocked by the outer peripheral edge of the rotating wafer W is always the same as that of the line sensor 203. Detected by position. Therefore, the position adjustment of the wafer W with respect to the rotation holding mechanism 202 is performed so that the position of the light input to the line sensor 203 is always the same.

  However, even if the lens 201 is used, the light from the light source 200 does not become completely parallel light, so an error also occurs in the light input to the line sensor 203. More specifically, there is a deviation between the position of the outer peripheral end of the wafer W in plan view and the position of the end of light blocked by the outer peripheral edge of the wafer W input to the line sensor 203. Therefore, the position of the outer peripheral end portion of the wafer W cannot be accurately grasped, and as a result, there is a limit in alignment accuracy. On the other hand, in order to cope with the recent high definition of semiconductor devices, higher precision alignment is required.

  The present invention has been made in view of such points, and an object of the present invention is to perform substrate alignment with high accuracy.

In order to achieve the above object, the present invention calculates the center position of the substrate by detecting the position of the end portion of the rotating substrate by holding the substrate in the rotation holding mechanism and rotating it, and calculating the calculated position. A position adjustment device that adjusts the position of a substrate based on information on the center position of the substrate , wherein the substrate is provided facing the vertical direction across the outer peripheral edge of the substrate held by the rotation holding mechanism. A light source that emits parallel light, a line sensor that detects light from the light source, and a moving mechanism that relatively moves the line sensor and the substrate held by the rotation holding function along the diameter direction of the substrate; Controlling the movement mechanism so that the line sensor and the substrate move relatively while irradiating the substrate with parallel light from the light source, and the relative movement distance between the line sensor and the substrate, Line sensor Control is performed to obtain a correlation between the relative movement distance and the amount of light movement based on the amount of light movement detected by the line sensor when the substrate is relatively moved. possess a control unit, and a relative movement distance between the substrate and the line sensor, correlation between the movement amount of light detected by the line sensor, relative to the substrate and the line sensor A difference between a distance between the line sensor and the amount of light detected by the line sensor and a relative distance between the line sensor and the substrate, and the control unit is based on the correlation. The correction value for correcting the difference between the relative movement distance between the line sensor and the substrate and the movement amount of the light detected by the line sensor is obtained, and the information on the center position of the substrate corrected by the correction value Based on the rotation holding It is characterized by performing control for matching the center position and the center position of the substrate structure.

  According to the present invention, the correlation between the movement amount of light detected by the line sensor when the line sensor and the substrate are relatively moved and the relative movement distance between the line sensor and the substrate is obtained. For this reason, when the position of the substrate is adjusted, the position of light detected by the line sensor is corrected based on this correlation, thereby enabling position detection with very little error. As a result, the substrate alignment operation can be performed with high accuracy.

  The control unit may include a storage unit that stores a correlation between a rotation speed command to the rotation holding mechanism and an actual rotation speed of the rotation holding mechanism.

  The correlation between the rotation command to the rotation holding mechanism and the actual rotation speed of the rotation holding mechanism may be an operation delay time of the actual rotation speed of the rotation holding mechanism with respect to the rotation command to the rotation holding mechanism.

The operation delay time of the actual rotation number of the rotation holding mechanism with respect to the rotation number command to the rotation holding mechanism is determined from the light source in a state in which the measurement substrate having the outer peripheral portion of the substrate formed with irregularities is held by the rotation holding mechanism. Irradiate the measurement substrate with parallel light, then rotate the rotation holding mechanism to detect the uneven shape of the measurement substrate with the line sensor,
Then, the rotation command from the control unit to the rotation holding mechanism may be obtained by comparing the timing at which the line sensor detects the uneven shape of the measurement substrate with the line sensor.

  The unevenness of the measurement substrate may be provided at equal intervals along the circumferential direction, and the uneven shape of the measurement substrate may be detected in a state where the rotation number of the rotation holding mechanism is constant.

  The control unit corrects the rotation command to the rotation holding mechanism with the operation delay time of the actual rotation number of the rotation holding mechanism stored in the storage unit, and rotates the rotation holding mechanism according to the corrected rotation command. May be.

According to another aspect of the present invention, the rotation holding mechanism holds and rotates the substrate, detects the position of the end of the rotating substrate, calculates the center position of the substrate, and calculates the calculated substrate A position adjustment method for adjusting a position of a substrate based on information on a center position, wherein the rotation holding mechanism is held by the rotation holding mechanism while irradiating parallel light from a light source to an outer peripheral edge portion of the substrate. Is detected by the line sensor when the line sensor and the substrate are moved relatively with respect to the line sensor provided facing the light source across the outer peripheral edge of the Find the difference between the amount of light movement and the relative movement distance between the line sensor and the substrate , determine the correlation between the difference and the relative movement distance between the line sensor and the substrate , based on the correlation, before Obtains a correction value for correcting the difference between the relative moving distance and the moving amount of light detected by the line sensor of the line sensor and the substrate, based on the corrected information of the center position of the substrate by the correction value, The center position of the rotation holding mechanism is matched with the center position of the substrate.

  The rotation command to the rotation holding mechanism may be corrected based on the correlation between the rotation command to the rotation holding mechanism and the actual rotation speed of the rotation holding mechanism.

  The correlation between the rotation command to the rotation holding mechanism and the actual rotation speed of the rotation holding mechanism may be an operation delay time of the actual rotation of the rotation holding mechanism with respect to the rotation command to the rotation holding mechanism.

The operation delay time of the actual rotation speed of the rotation holding mechanism with respect to the rotation command to the rotation holding mechanism is measured from the light source in a state in which the measurement holding substrate in which the outer peripheral portion of the substrate is formed uneven by the rotation holding mechanism is held. Irradiate the substrate for parallel light, then rotate the rotation holding mechanism to detect the uneven shape of the measurement substrate with the line sensor,
Then, the rotation command to the rotation holding mechanism may be obtained by comparing the timing at which the line sensor detects the uneven shape of the measurement substrate.

  The unevenness of the measurement substrate may be provided at equal intervals along the circumferential direction, and the uneven shape of the measurement substrate may be detected in a state where the rotation number of the rotation holding mechanism is constant.

According to another aspect of the present invention, there is provided a program that operates on a computer of a control unit that controls the substrate position adjustment device so that the substrate position adjustment method is executed by the substrate position adjustment device. The

  According to another aspect of the present invention, a readable computer storage medium storing the program is provided.

  According to the present invention, substrate alignment can be performed with high accuracy.

It is a top view which shows the outline of a structure of the position adjustment apparatus concerning this Embodiment. It is a longitudinal cross-sectional view which shows the outline of a structure of the position adjustment apparatus concerning this Embodiment. It is a top view which shows the outline of a structure of a conveyance arm. It is explanatory drawing of the detection method of the edge part position of a wafer. It is a flowchart which shows the main processes of wafer position adjustment. It is explanatory drawing which shows the position adjustment method of a wafer. It is explanatory drawing which shows the position adjustment method of a wafer. It is a graph which shows the correlation of the position of a line sensor, and the difference which arises there. It is a graph which shows correlation with rotation instruction | command and the operation delay time of real rotation. It is explanatory drawing which shows the detection method of the edge part using the wafer for a measurement. It is a graph which shows the correlation with the rotation command to a chuck | zipper drive part, and the position of the edge part detected by a line sensor. It is a table | surface which shows the correlation with the position of a line sensor, and the difference which arises there. It is explanatory drawing which shows the position adjustment method of a board | substrate.

  Hereinafter, a wafer W position adjusting apparatus 1 according to an embodiment of the present invention will be described. FIG. 1 is a plan view showing an outline of the configuration of the position adjusting device 1. FIG. 2 is a plan view illustrating the outline of the configuration of the position adjusting device 1.

  The position adjusting device 1 has a housing 10. A shutter 12 that opens and closes the loading / unloading port 11 for the wafer W is provided on a side surface of the housing 10. The wafer W is loaded / unloaded from the loading / unloading port 11 by a transfer arm 60 described later.

  A wafer chuck 20 as a rotation holding mechanism for holding the wafer W is provided inside the housing 10. The wafer chuck 20 includes a holding unit 21 that holds the wafer W and a support shaft 22 that supports the lower surface of the holding unit 21. The holding unit 21 has a horizontal upper surface and is formed in a substantially disk shape that is smaller than the diameter of the wafer W and is horizontal. Further, a suction port (not shown) for sucking the wafer W, for example, is provided on the upper surface of the holding unit 21. The wafer W can be sucked and held on the holding portion 21 by suction from the suction port.

  The support shaft 22 that supports the wafer W is connected to a chuck drive unit 30 provided below the wafer chuck 20. The chuck drive unit 30 can rotate the support shaft 22 in a desired direction at a desired number of rotations based on a command signal from the control unit 100 to be described later, whereby the wafer chuck 20 is rotatable. . Further, the chuck driving unit 30 is attached on a rail 31 provided on the bottom surface in the housing 10. The rail 31 extends along the Y direction in FIG. 1, and the wafer chuck 20 can be moved along the rail 31 by the chuck driving unit 30. That is, the wafer chuck 20 can move between a delivery position P1 for carrying the wafer W in and out of the housing 10 and an alignment position P2 for adjusting the position of the wafer W.

  For example, a light source 40 that irradiates parallel light downward vertically is provided on the lower surface of the ceiling of the housing 10. The light source 40 is disposed at a position where the outer peripheral edge of the wafer W held by the wafer chuck 20 can be irradiated with parallel light at the alignment position P2. The light source 40 includes a light emitting unit 41 such as a lamp and a lens 42 that collimates light from the light emitting unit 41.

  A line sensor 50 that detects light emitted from the light source 40 is provided below the light source 40. The line sensor 50 is disposed at a position facing the light source 40 across the wafer W held by the wafer chuck 20. Therefore, a part of the light emitted from the light source 40 is blocked by the wafer W, and the light not blocked by the wafer W is input to the light receiving portion of the line sensor 50. The line sensor 50 is connected to the control unit 100 described later.

  As shown in FIG. 1, the light receiving portion 51 of the line sensor 50 is provided along the direction in which the rail 31 extends. In other words, the light receiving portion 51 of the line sensor 50 is parallel to the rail 31 in plan view. Therefore, when the chuck driving unit 30 is moved along the rail 31 in a state where light is irradiated from the light source 40 to the wafer W, the light input from the light source 40 and input to the line sensor 50 without being blocked by the wafer W The position of the boundary with the shadowed portion of the wafer W is configured to move in parallel along the length direction of the light receiving portion 51.

  As shown in FIG. 3, the transfer arm 60 described above has a substantially C-shaped arm portion 60 a having a diameter slightly larger than the wafer W, for example. Inside the arm portion 60a, support portions 60b projecting inward and supporting the outer peripheral portion of the wafer W are provided at a plurality of locations, for example, three locations. The transfer arm 60 is configured to be movable back and forth, right and left and up and down by a driving mechanism (not shown), and can transfer the wafer W and the wafer W in the housing 10 from the loading / unloading port 11.

  The above position adjusting device 1 is provided with a control unit 100 as shown in FIG. The control unit 100 is a computer including, for example, a CPU and a memory, and is generated by a program storage unit 101, a calculation unit 102 that performs calculation processing of a signal input to the control unit 100, and a calculation unit 102 as illustrated in FIG. Storage means 103 for storing the received information. The program storage unit stores a program for controlling operations of the chuck driving unit 30 and the transfer arm 60 in the position adjusting apparatus 1. The program storage means 101 is a computer-readable storage medium such as a computer-readable hard disk (HD), flexible disk (FD), compact disk (CD), magnet optical desk (MO), memory card, or the like. May be. Further, the program may be recorded in this storage medium and installed in the control unit 100 from the storage medium.

  The calculation means 102 performs calculation processing for obtaining a correction value for adjusting the position of the wafer W based on a signal from the line sensor 50 input to the control unit 100 and a control command signal to the chuck driving unit 30. It is. Before describing the arithmetic processing in the arithmetic means 102, the position adjustment of the wafer W will be described first.

  In adjusting the position of the wafer W, as shown in FIG. 4, the wafer W is rotated while being held by the wafer chuck 20, and the light emitted from the light source 40 is detected by the line sensor 50 (step of FIG. 5). S1). At this time, the position of the boundary L between the light input to the line sensor 50 and the portion that is shaded by the outer peripheral end of the rotating wafer W is obtained as the position of the outer peripheral end of the wafer W. When the position of the boundary between the light input to the line sensor 50 and the portion that is shaded by the peripheral edge of the rotating wafer W is always detected at the same position of the line sensor 50, It is determined that the center position matches the center position of the wafer chuck. On the other hand, when the center position is shifted, the position of the boundary L detected by the line sensor 50 changes, for example, in a periodic function having a predetermined amplitude.

  Therefore, in the calculation means 102, the amount of deviation between the center position of the wafer W and the center position of the wafer chuck 20 from the change in the detection position of the boundary L by the line sensor 50, specifically, the center position of the wafer W and the wafer chuck 20 is determined. The straight line distance from the center position of is calculated (step S2 in FIG. 5). At the same time, the shift direction in the XY direction between the center position of the wafer W and the center position of the wafer chuck 20 is calculated. (Step S3 in FIG. 5). Subsequently, based on the calculated shift amount and shift direction, as shown in FIG. 6, for example, the control unit 100 sets the center position of the wafer W on the Y axis with the center of the wafer chuck 20 as the origin. , The wafer chuck 20 is rotated by a predetermined angle θ (step S4 in FIG. 5). Next, as shown in FIG. 7, the wafer W is moved along the X axis by the transfer arm 60 so that the center position of the wafer W is positioned at the center of the wafer chuck 20 (step S5 in FIG. 5). Thereby, the center position of the wafer W is adjusted to the center position of the wafer chuck 20.

  Next, the wafer chuck 20 is rotated in a state where the center positions of the wafer W and the wafer chuck 20 coincide with each other, and the position of the notch portion is detected by the line sensor 20 (step S6 in FIG. 5). Subsequently, the wafer W is rotated by a predetermined angle by the wafer chuck 20 so that the notch is positioned at a predetermined position in the circumferential direction of the wafer W according to a rotation command from the control unit 100 (step S7 in FIG. 5), and the wafer. W alignment work is completed.

  At this time, if the light from the light source 40 is completely parallel light, the center position of the wafer W and the center position of the wafer chuck 20 are completely matched by the above-described operation. However, since the light from the light source 40 is not completely parallel light in practice, it is between the actual position of the end of the wafer W in plan view and the position of the boundary L detected by the line sensor 50. Misalignment exists, resulting in measurement errors.

  Therefore, the calculation means 102 obtains an error caused by the influence of the light source 40 and a correction value for correcting the error. In determining the error, first, parallel light is irradiated from the light source 40 onto the wafer W held on the wafer chuck 20. At this time, the rotation of the wafer chuck 20 is stopped.

  Next, a predetermined distance with respect to the chuck driving unit 30 by the control unit 100, in this embodiment, the horizontal relative distance between the chuck driving unit 30 and the line sensor 50 is, for example, 0.4 mm to 1 mm each. A command signal is output so as to move in steps, and the wafer chuck 20 is moved in the Y direction in FIG. 4 (step T1 in FIG. 5). A change in the position of the boundary L accompanying the movement of the chuck driving unit 30 is detected by the line sensor 50 (step T2 in FIG. 5). At this time, if the light emitted from the light source 40 is completely parallel light, the relative moving distance between the chuck driving unit 30 and the line sensor 50 and the moving amount of the boundary L detected by the line sensor 50 are: The difference is zero because they match completely. However, as described, there is a slight difference between the moving distance of the chuck driving unit 30 and the moving amount of the boundary L detected by the line sensor 50. Even if the difference between the movement distance of the chuck driving unit 30 and the movement amount of the boundary L detected by the line sensor 50 is not zero at a predetermined position of the line sensor 50, This difference may be zero at the position.

  Therefore, the calculation means 102 first calculates the difference between the movement distance of the chuck drive unit 30 and the movement amount of the boundary L detected by the line sensor 50 along the length direction of the line sensor 50 (Y direction in FIG. 1). (Step T3 in FIG. 5). Then, a correlation between this difference and the movement distance of the chuck driving unit 30, in other words, a correlation between the position of the line sensor 50 and the difference generated at that position is obtained (step T4 in FIG. 5).

  Specifically, as shown in FIG. 8, for example, the movement of the boundary L detected by the line sensor 50 with the horizontal axis representing the movement distance of the chuck drive unit 30 replaced with the position of the detection unit 51 of the line sensor 50. The difference in quantity is plotted on the vertical axis, and the correlation is obtained. “Measurement data” in FIG. 7 represents an actual difference calculated by the calculation means 102. The “approximation formula” and “corrected data” will be described next. In this embodiment, for example, as shown in FIG. 4, when the wafer chuck 20 is moved along the line sensor 50, there is a correlation between the movement distance of the wafer chuck 20 and the difference in the movement amount of the boundary L. An example of a trigonometric function will be described.

  When the correlation between the movement distance of the chuck driving unit 30 and the difference in the movement amount of the boundary L is obtained, the computing unit 102 obtains an approximate expression F of “measurement data”. In the present embodiment, the approximate expression F is, for example, a trigonometric function as described above. Next, an inverse function of the approximate expression F is obtained (step T5 in FIG. 5). Then, the product of the inverse function of the approximate expression F and “measurement data” is calculated as “corrected data” after correcting an error caused by the light source 40. In other words, the inverse function of the approximate expression F becomes a correction value for correcting an error caused by the light source 40. Note that information on the inverse function of the approximate expression F generated by the calculation means 102 is stored in the storage means 103.

  Then, the computing means 102 corrects the position of the boundary L detected by the line sensor 50 in step S1 of FIG. 5 based on the inverse function information of the “correction formula” read from the storage means 103, and “corrected data”. Is calculated. As a result, a more accurate position of the boundary L excluding errors due to the light source 40 is detected. Then, in step S2 of FIG. 5, the deviation amount of the center position between the wafer W and the wafer chuck 20 is calculated based on this “corrected data”. As a result, it is possible to grasp a more accurate deviation amount excluding an error caused by the light source 40 and to adjust the position of the wafer W with high accuracy.

  In addition to the correction value of the shift amount between the center position of the wafer W and the center position of the wafer chuck 20, the calculation means 102 also performs calculation processing for correcting the shift in the rotation direction of the wafer W. The correction of the positional deviation in the rotation direction of the wafer W will be described.

  The position adjustment of the rotation direction of the wafer W is performed by rotating the wafer W by the wafer chuck 20, adjusting the position of the notch portion of the wafer W, and arranging the wafer W in a predetermined direction. At this time, the position of the notch portion is determined by rotating the wafer chuck 20 while irradiating light onto the wafer W from the light source 40, and the position of the notch portion detected by the line sensor 50 and the rotation command from the control unit 100 to the wafer chuck 20. It is obtained by checking the signal.

  However, due to the delay in the operation of the motor of the chuck drive unit 30 and the response speed due to the switching circuit device that operates the motor, the actual rotation operation of the wafer chuck 20 is performed from the control unit 100 to the chuck drive unit 30. A delay occurs with respect to the speed command. Specifically, for example, as shown in the graph of FIG. 9, during the rotation, the actual rotation of the motor is delayed with respect to the rotation command, and becomes a stable value after 100 msec. Therefore, even if the position of the notch portion is specified and a control signal is output to the chuck drive unit 30 so as to move the specified notch portion to a position in the predetermined rotation direction, the actual notch position of the wafer W is It does not coincide with the position corresponding to the command from 100. In addition, since the rotation command and the actual rotation do not match, an error occurs in the deviation direction calculated in step S3. Therefore, a correction value for correcting the positional deviation in the rotation direction of the wafer W is obtained by the calculation means 102.

  When obtaining a correction value for correcting the positional deviation in the rotation direction of the wafer W, rectangular uneven edges E are formed at equal intervals along the outer periphery of the wafer W, for example, as shown in FIG. A measurement wafer A is used. In the present embodiment, an example will be described in which a measurement wafer A in which irregularities are alternately formed every 1/8 rotation is used as the edge portion E.

  In the state irradiated with light from the light source 40, the measurement wafer A is held and rotated by the wafer chuck 20, and the uneven shape is detected by the line sensor 50 (step U1 in FIG. 5). As a result, a step function waveform as shown in FIG. 11 is obtained. Then, the calculation means 102 compares the waveform obtained by the line sensor 50 with the rotation command from the control unit 100. More specifically, as shown in FIG. 11, the waveform obtained by the line sensor 50 and the rotation command from the control unit 100 are plotted on the same time axis. Then, on the control command, the time during which the measurement wafer A should be rotated by 1/8 and the time at which the unevenness is replaced in the waveform obtained by the line sensor 50 are shifted by time Tn (n is an integer). Become. This time Tn is the operation delay time of the wafer chuck 20.

  Subsequently, the measurement wafer A is continuously rotated. Then, the calculation means 102 determines that the rotation speed of the wafer chuck 20 is stable when the values of Tn−1 and Tn become the same, and uses the value of Tn at that time as the operation delay time for correction. Obtained (step U2 in FIG. 5). And this operation | movement delay time is memorize | stored in the memory | storage means 103 as a correction value which correct | amends the rotation command to the chuck | zipper drive part 30 from the control part 100 (process U3 of FIG. 5).

  In step S3 of FIG. 5, the correction value stored in the storage unit 103 in step U3 is read, and the rotation command corrected by the correction value is used, so that a more accurate displacement direction of the wafer W can be calculated. Further, after detecting the position of the notch portion of the wafer W in step S6 in FIG. 5, the correction value stored in the storage means 103 in step U3 is read in step S7, and the rotation command corrected by the correction value is used. Accurate adjustment of the position in the rotation direction is possible.

  The position adjusting apparatus 1 according to the present embodiment is configured as described above. Next, position adjustment performed by the position adjusting apparatus 1 will be described.

  In the position adjustment of the wafer W by the position adjusting device 1, the wafer chuck 20 is first moved to the delivery position P1. Next, the transfer arm 60 holds the wafer chuck 20 on the delivery position P1. Thereafter, the chuck drive unit 30 moves the wafer chuck 20 to the alignment position P2.

  Next, the wafer chuck 20 is rotated by the chuck driving unit 30 while irradiating light from the light source 40. At this time, the line sensor 50 detects the boundary L that is the position of the outer peripheral edge of the wafer W. The computing means 102 obtains “after-correction data” based on the inverse function of the “correction formula” stored in the storage means 103 based on the position information of the wafer W and the notch portion detected by the line sensor 50. Then, based on this “corrected data”, a deviation amount between the center of the wafer W and the center of the wafer chuck 20 is calculated. Further, based on the rotation command corrected by the correction value stored in the storage unit 103, the deviation direction of the wafer W is calculated. Subsequently, the center position of the wafer chuck 20 and the center position of the wafer W are aligned by the transfer arm 60.

  Thereafter, the wafer chuck 20 is rotated in a state where the center positions of the wafer W and the wafer chuck 20 coincide with each other, and the position of the notch portion is detected by the line sensor 20. The calculation means reads the operation delay time stored in the storage means 103 and corrects the rotation command to the chuck drive unit 30 by this operation delay time. Next, the control unit 100 outputs a corrected rotation command to the chuck driving unit 30 and performs alignment of the wafer W in the rotation direction. Thus, the adjustment of the center position of the wafer W and the position in the rotation direction is completed, and a series of alignment operations are completed.

  When the alignment is completed, the chuck drive unit 30 moves the wafer chuck 20 from the alignment position P2 to the delivery position P1. At the delivery position P1, the wafer W is unloaded from the position processing apparatus 1 by the transfer arm 60. Thereafter, the next wafer W is carried into the position processing apparatus 1 and alignment operations are sequentially performed.

  According to the above embodiment, the amount of movement of light detected by the line sensor 50 when the line sensor 50 and the wafer W are relatively moved in the process T3, and the line sensor 50 and the wafer W The difference from the relative movement distance is obtained. In step T4, a correlation between this difference and the position of the line sensor 50, more specifically, a correlation indicating how much difference occurs at which position of the line sensor 50 is obtained. Therefore, when the position of the wafer W is adjusted, the position of the boundary L detected by the line sensor 50 is corrected based on this correlation, so that position detection with very little error can be performed. As a result, the wafer W alignment operation can be performed with high accuracy. Thereby, the yield of the wafers W due to the alignment mismatch can be improved.

  If the difference between the amount of movement of the light detected by the line sensor 50 and the relative movement distance between the line sensor 50 and the wafer W is obtained and this difference is excessive, the line sensor 50 or the light source 40, it is assumed that some trouble has occurred. Therefore, according to the present invention, by evaluating the magnitude of this difference, it is possible to check whether or not the position adjusting device 1 is defective, leading to an improvement in reliability.

  Further, in the above embodiment, since the operation delay time in the rotation direction of the chuck drive unit 30 is obtained in Step U1 to Step U3, not only the wafer center position but also the rotation direction position adjustment is extremely highly accurate. It can be carried out.

  In the above embodiment, the “correction formula” used for position adjustment of the center position is obtained as an approximate formula of “measurement data”. However, the calculation method of the “correction formula” is not limited to the example of the present embodiment. . For example, instead of graphing the difference between the movement amount of the boundary L and the movement distance of the chuck drive unit 30 obtained in step T3, the difference may be obtained as a matrix as shown in FIG. In such a case, the shift amount corresponding to the position of the boundary L detected in step S1 is read from the matrix. Then, the amount of deviation between the center position of the wafer W and the center position of the wafer chuck 20 is calculated in step S2 by subtracting this deviation amount from the boundary L position detected in step S1 as the actual boundary L position. Even in this case, it is possible to detect the end position of the wafer W with less error, and as a result, the alignment operation of the wafer W can be performed with high accuracy.

  In the above embodiment, in steps T1 to T3, the wafer W is moved with respect to the line sensor 50 to calculate the deviation amount of the boundary L. However, if the line sensor 50 and the wafer W move relative to each other. Alternatively, the position of the wafer W may be fixed, and the line sensor 50 may be moved relative to the wafer W.

  In the above embodiment, the light source 40 is disposed above the wafer W and the line sensor 50 is disposed below the wafer W. However, the light source 40 and the line sensor 50 are configured such that light from the light source 40 is transmitted by the wafer W. For example, the light source 40 may be disposed below the wafer W and the line sensor 50 may be disposed above the wafer W as long as the position of the boundary L generated by being blocked can be grasped.

  Further, in the above embodiment, the measurement wafer A having a rectangular uneven edge portion E is used, but the shape of the measurement wafer A is not limited to the present embodiment. If the line sensor 50 can detect the position change of the edge of the wafer W, that is, the position of the wafer W in the rotation direction, it may be triangular unevenness and can be arbitrarily set. Note that the number of the uneven edge portions E can be set arbitrarily.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood. The present invention is not limited to this example and can take various forms. The present invention can be applied to scenes that require wafer alignment, for example, a bonding apparatus that bonds wafers, in addition to photolithography. Further, the present invention can also be applied to a case where the substrate is another substrate such as an FPD (flat panel display) other than a wafer or a mask reticle for a photomask.

DESCRIPTION OF SYMBOLS 1 Position adjustment apparatus 10 Housing | casing 20 Wafer chuck 30 Chuck drive part 40 Light source 50 Line sensor 60 Transfer arm 100 Control part 101 Program storage means 102 Calculation means 103 Storage means A Measurement wafer E Edge part L Boundary P1 Delivery position P2 Alignment position W wafer

Claims (13)

The substrate is held and rotated by the rotation holding mechanism, the center position of the substrate is calculated by detecting the position of the end of the rotating substrate, and the position of the substrate is calculated based on the calculated information on the center position of the substrate. A position adjusting device for adjusting,
A light source for irradiating the substrate with parallel light and a line sensor for detecting the light from the light source, which are provided facing each other in the vertical direction across the outer peripheral edge of the substrate held by the rotation holding mechanism;
A moving mechanism for relatively moving the line sensor and the substrate held by the rotation holding function along the diameter direction of the substrate;
The moving mechanism is controlled so that the line sensor and the substrate move relatively while irradiating the substrate with parallel light from the light source, the relative moving distance between the line sensor and the substrate, and the line Control for obtaining a correlation between the relative movement distance and the amount of light movement based on the amount of light movement detected by the line sensor when the sensor and the substrate are relatively moved. have a, and a control unit that performs,
The correlation between the relative movement distance between the line sensor and the substrate and the amount of light detected by the line sensor is the relationship between the relative movement distance between the line sensor and the substrate and the line sensor. It is a correlation between the difference between the detected movement amount of light and the relative movement distance between the line sensor and the substrate,
The control unit obtains a correction value for correcting a difference between a relative movement distance between the line sensor and the substrate and a movement amount of light detected by the line sensor based on the correlation, and the correction value A position adjustment apparatus that performs control to match the center position of the rotation holding mechanism with the center position of the substrate based on the information on the center position of the substrate corrected by the above . 2. The position adjustment of the substrate according to claim 1 , wherein the control unit includes a storage unit that stores a correlation between a rotation speed command to the rotation holding mechanism and an actual rotation speed of the rotation holding mechanism. apparatus. The correlation between the rotation command to the rotation holding mechanism and the actual rotation speed of the rotation holding mechanism is an operation delay time of the actual rotation speed of the rotation holding mechanism with respect to the rotation command to the rotation holding mechanism. The apparatus for adjusting a position of a substrate according to claim 2 . The operation delay time of the actual rotation number of the rotation holding mechanism with respect to the rotation number command to the rotation holding mechanism is determined from the light source in a state in which the measurement substrate having the outer peripheral portion of the substrate formed with irregularities is held by the rotation holding mechanism. Irradiate the measurement substrate with parallel light, then rotate the rotation holding mechanism to detect the uneven shape of the measurement substrate with the line sensor,
Then a rotation command to said rotary holding mechanism from the control unit, characterized in that it is calculated by comparing the timing of detecting the irregular shape of the measurement substrate in said line sensor, according to claim 3 Board position adjustment device. The unevenness of the measurement substrate is provided at equal intervals along the circumferential direction, and the uneven shape of the measurement substrate is detected in a state where the rotation number of the rotation holding mechanism is constant. Item 5. The substrate position adjusting apparatus according to Item 4 . The control unit corrects the rotation command to the rotation holding mechanism with the operation delay time of the actual rotation speed of the rotation holding mechanism stored in the storage unit,
6. The substrate position adjusting apparatus according to claim 4 , wherein the rotation holding mechanism is rotated by the corrected rotation command. The substrate is held and rotated by the rotation holding mechanism, the center position of the substrate is calculated by detecting the position of the end of the rotating substrate, and the position of the substrate is calculated based on the calculated information on the center position of the substrate. A position adjustment method for performing adjustment,
While irradiating parallel light from the light source to the outer peripheral edge of the substrate, the rotation holding mechanism is applied to the line sensor provided facing the light source across the outer peripheral edge of the substrate held by the rotation holding mechanism. Move relatively,
Obtaining the difference between the amount of light detected by the line sensor when the line sensor and the substrate are relatively moved , and the relative movement distance between the line sensor and the substrate ;
Obtaining a correlation between the difference and a relative movement distance between the line sensor and the substrate ;
Based on the correlation, a correction value for correcting a difference between a relative movement distance between the line sensor and the substrate and a movement amount of light detected by the line sensor is obtained,
A substrate position adjustment method , wherein the center position of the rotation holding mechanism and the center position of the substrate are made to coincide with each other based on the information on the center position of the substrate corrected by the correction value . 8. The substrate according to claim 7 , wherein the rotation command to the rotation holding mechanism is corrected based on the correlation between the rotation command to the rotation holding mechanism and the actual rotation speed of the rotation holding mechanism. Position adjustment method. The correlation between the rotation command to the rotation holding mechanism and the actual rotation speed of the rotation holding mechanism is an operation delay time of the actual rotation of the rotation holding mechanism with respect to the rotation command to the rotation holding mechanism, The substrate position adjusting method according to claim 8 . The operation delay time of the actual rotation speed of the rotation holding mechanism with respect to the rotation command to the rotation holding mechanism is measured from the light source in a state in which the measurement holding substrate in which the outer peripheral portion of the substrate is formed uneven by the rotation holding mechanism is held. Irradiate the substrate for parallel light, then rotate the rotation holding mechanism to detect the uneven shape of the measurement substrate with the line sensor,
The position adjustment of the substrate according to claim 9 , wherein the position adjustment is obtained by comparing a rotation command to the rotation holding mechanism and a timing at which the line sensor detects the uneven shape of the measurement substrate. Method. The unevenness of the measurement substrate is provided at equal intervals along the circumferential direction, and the uneven shape of the measurement substrate is detected in a state where the rotation number of the rotation holding mechanism is constant. Item 11. The method for adjusting the position of a substrate according to Item 10 . A program that operates on a computer of a control unit that controls the substrate position adjustment device so that the substrate position adjustment device according to any one of claims 7 to 11 is executed by the substrate position adjustment device. A readable computer storage medium storing the program according to claim 12 .

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