JP6057640B2 - Alignment apparatus, rotation condition adjusting method and apparatus therefor, and substrate processing apparatus - Google Patents

Description

  The present invention relates to an alignment apparatus for aligning a substrate such as a semiconductor wafer or a micromachine device, a rotation condition adjusting method and apparatus therefor, and a substrate processing apparatus.

  In a semiconductor manufacturing line, a plurality of semiconductor wafers are usually housed in each slot of a cassette and supplied to the line in units of cassettes. The cassette containing the semiconductor wafers is set at the correct position in the loader chamber, and the semiconductor wafers are taken out one by one from the cassette by the transfer robot and transferred to a chamber for processing or inspection.

  By the way, the position of the semiconductor wafer stored in the cassette may be shifted in the cassette. In addition, in the process in which the semiconductor wafer is placed on the hand or fork of the transfer robot and transferred to and received from the chamber, the position of the semiconductor wafer relative to the transfer robot hand may be displaced. .

  Conventionally, an alignment device (aligner) has been used to measure the amount of displacement (displacement, eccentricity) of the position of the semiconductor wafer and place the semiconductor wafer on the correct position on the hand of the transfer robot ( Patent Documents 1 to 3).

  The alignment apparatus normally includes a turntable, a drive unit that rotationally drives the turntable, and a substrate position detection unit that detects the position of the semiconductor wafer placed on the turntable. In the conventional alignment apparatus, it is necessary to rotate the semiconductor wafer on the turntable in order to measure the displacement amount of the semiconductor wafer. At that time, it is advantageous to increase the rotational speed and acceleration (rotational acceleration) of the turntable because the time required for measurement can be shortened. However, if the rotational speed or acceleration becomes too large, the semiconductor wafer slips on the turntable and a positional shift occurs.

  Conventionally, as a measure for preventing a semiconductor wafer from slipping, there is known a method of attaching a semiconductor wafer having a high friction coefficient such as an O-ring to a turntable or providing a suction mechanism using a negative pressure (patent) References 1, 2).

JP 2004-47654 A JP 2009-81266 A JP 2007-95881 A

  As described above, measures have been taken to prevent the semiconductor wafer from slipping, but there is a limit to this, and if the rotational speed or acceleration of the turntable is further increased, there is a possibility of slipping. In semiconductor production lines, many types of semiconductor wafers with different shapes, weights, materials, surface roughness, etc. are transported. Depending on the type of semiconductor wafer, the rotational speed and acceleration that limit slipping vary. Come.

  In addition to semiconductor wafers, semiconductor manufacturing lines are used to process micromachine devices with micro structures obtained by processing by MEMS (Micro Electro Mechanical Systems). In this case, the surface is uneven. Because there are holes or holes, the situation and limit of slipping are different from those of semiconductor wafers.

  Therefore, when performing alignment in the alignment apparatus, it is necessary to variously adjust the rotation speed and acceleration according to the substrate to be used. For that purpose, for example, the rotational speed or acceleration must be variously changed to detect the presence or absence of substrate displacement, which is not easy. In particular, in recent years, high-mix low-volume production has been frequently performed, and the number of setup changes has increased, and the work of setting the rotation speed and acceleration every time the type of substrate changes requires a lot of time and labor.

  As a result, the rotational speed and acceleration of the turntable are set to be small so that the substrate does not slip, and therefore the time required for alignment is long.

  The present invention has been made in view of the above-described problems, and in an alignment apparatus that performs alignment of a substrate such as a semiconductor wafer or a micromachine device, it is possible to easily measure and adjust the rotational speed or acceleration so that the substrate does not slip. The purpose is to.

A method according to an embodiment of the present invention includes a rotating table, a driving unit that rotationally drives the rotating table, and a substrate position detecting unit that detects the position of a disk-shaped substrate placed on the rotating table. A rotation condition adjusting method for an apparatus, wherein the substrate position detecting means is arranged along the radial direction and at different angular positions at a peripheral edge of the substrate in order to detect the position of the substrate. Based on the two line sensors that detect the edge positions, and the edge positions detected by the two line sensors, the amount of displacement caused by the displacement of the substrate with respect to the turntable as the turntable rotates. Displacement calculation means for obtaining the two line sensors, the angular positions with respect to the center point of the turntable are shifted from each other by approximately 90 degrees Arranged in condition, moreover, at least one line sensor, the are arranged with a shift by a minute angle α from the one of the axis of the X-axis and Y-axis that defines the XY plane, on the turntable with the substrate is placed, running, and a second step of detecting by the first step and the substrate position detection means the amount of displacement for rotating the turntable by the driving means, it is detected Based on the amount of displacement, a limit speed or limit acceleration that is a rotation speed or acceleration that prevents the substrate from slipping is obtained.

An apparatus according to an embodiment of the present invention includes a turntable, a driving unit that rotationally drives the turntable, and a peripheral edge of the substrate for detecting the position of a disk-like substrate placed on the turntable. Two line sensors which are arranged along the radial direction in the portion and at different angular positions and detect the edge positions, respectively, and the displacement of the substrate based on the edge positions detected by the two line sensors A substrate position detecting means including a displacement calculating means for obtaining a quantity; and a control means for controlling the driving means and the substrate position detecting means, wherein the two line sensors are angled with respect to a center point of the turntable The positions are shifted by approximately 90 degrees from each other, and at least one line sensor has one of the X axis and the Y axis that define the XY plane. It is arranged with a shift by a minute angle α from above.
The control means includes a first means for rotating the turntable by the drive means with the substrate placed on the turntable, and a second means for detecting the displacement amount by the substrate position detection means. Means, a third means for determining whether or not a displacement caused by the displacement of the substrate with respect to the turntable as the turntable rotates exceeds a threshold value; and A fourth means for recording the rotational speed or rotational acceleration of the turntable at or immediately before as the limit speed or the limit acceleration, and when the displacement does not exceed the threshold value And fifth means for controlling to repeat the operation of the first to third means by increasing the set value of the rotational speed or rotational acceleration of the turntable.

  According to the present invention, in the alignment apparatus, it is possible to easily measure and set the rotation speed or acceleration so that the substrate does not slip. As a result, the time required for alignment in the alignment apparatus is reduced, and as a result, the overall processing time in the substrate processing apparatus can be reduced.

It is a top view which shows the outline | summary of the substrate processing apparatus of one Embodiment of this invention. It is a top view which shows the outline | summary of the substrate processing apparatus of the other form of this invention. It is a partial cross section front view which shows one Embodiment of the structure of an alignment apparatus. It is a top view of the alignment apparatus of FIG. It is a figure which shows the relationship between a semiconductor wafer and a sensor. It is a figure for demonstrating the arrangement position of a sensor, and the shift | offset | difference of a board | substrate. It is a figure for demonstrating the shift | offset | difference of the circumferential direction of a board | substrate. It is a figure for demonstrating the relational expression of edge displacement (x, y) and center displacement (X1, Y1). It is a block diagram which shows the example of a structure of the control part of an alignment apparatus. It is a timing diagram which shows the example of the operation state at the time of positioning in the circumferential direction. It is a timing diagram which shows the example of the operation state in the case of the measurement of the limit speed in the stepwise speed increase method. FIG. 12 is an enlarged timing diagram showing a part of FIG. 11. It is a timing diagram which shows the example of the operation state at the time of the measurement of a limit acceleration. It is a timing diagram which shows the example of the operation state in the case of the measurement of the limit speed in the continuous speed increase method. It is a figure which shows the example of the content of the memory which stores a limit speed and a limit acceleration. It is a flowchart which shows the flow of the outline operation | movement of an alignment apparatus. It is a flowchart which shows the flow of adjustment of rotation conditions. It is a flowchart which shows the flow of a preliminary | backup process. It is a flowchart which shows the flow of the measurement of the limit speed | velocity in a step-wise speed increase method. It is a flowchart which shows the flow of a measurement of a limit acceleration. It is a flowchart which shows the flow of the measurement of the limit speed in the continuous speed increase method.

Hereinafter, embodiments of the present invention will be described. In the following embodiment, a substrate processing apparatus 1 that processes a substrate WD will be described. The substrate WD to be processed by the substrate processing apparatus 1 may be a semiconductor wafer, a micromachine device, or another substrate. Also, the material of the substrate WD may be glass, resin, silicon, or other materials. In the following embodiments, the substrate WD has a disk shape, but it can be applied to other shapes such as an oval, a square, a rectangle, and other polygons. It is.
[Configuration of substrate processing equipment]
FIG. 1 is a plan view of a substrate processing apparatus 1 according to an embodiment.

  In FIG. 1, a substrate processing apparatus 1 includes a main body frame 2, a chamber 3, a loader unit 4, a transfer robot 5, an alignment device 6, a control device 7, and the like.

  In the loader unit 4, a cassette CA storing a plurality of substrates WD is accurately positioned and set. Each substrate WD is stored in a slot provided in the cassette CA, and is taken in and out by a hand (fork) 5a of the transfer robot 5.

  For example, a NC robot-controlled multi-axis robot is used as the transfer robot 5, and the substrate WD is lifted by ascending after the hand 5 a at the tip is inserted below the substrate WD. As a result, the substrate WD is placed on the hand 5a, and the substrate WD is moved to a predetermined position by the movement or rotation of the arm.

  That is, for example, the substrate WD in the cassette CA is taken out by the hand 5 a of the transfer robot 5 and set at a predetermined position of the alignment device 6. The alignment device 6 measures (measures) a displacement amount (deviation amount) from a normal position (reference position) of the position where the substrate WD is set, and transmits the measured displacement amount to the transport robot 5. The transfer robot 5 takes out the substrate WD from the alignment device 6 by the hand 5 a at the position where the measured displacement amount is corrected, and sets it at a predetermined position in the chamber 3. Thereby, the substrate WD is set at an accurate position in the chamber 3.

  In the chamber 3, various processes such as CVD, sputtering, etching, or inspection are performed on the substrate WD, and thereafter, the substrate 5 is taken out by the hand 5a and returned to the cassette CA.

  The control device 7 controls the overall operation and process of the substrate processing apparatus 1. The control device 7 includes an operation panel and a display panel for a user to operate, and an interface for exchanging signals or data with other devices or networks.

  Note that the configuration, structure, shape, and the like of the substrate processing apparatus 1 can be various other than those described above. An example is shown in FIG.

In the substrate processing apparatus 1B shown in FIG. 2, a plurality of processing apparatuses KS1 and 2 are installed. Each processing apparatus KS1, 2 is provided with chambers 3B1, 3B2. The transfer robot 5B can run, and takes in and out the substrate WD between the chambers 3B1, 3B2, the alignment apparatus 6, and the cassette CA.
[Structure of alignment device]
Next, the alignment apparatus 6 will be described.

  As shown in FIGS. 3 and 4, the alignment apparatus 6 includes a housing 11, a turntable 12, a motor 13, two line sensors 14 and 15, a spot sensor 16, a control unit 17 (see FIG. 9), and the like.

  The housing 11 is formed in a rectangular parallelepiped shape by a plurality of long mold members 11a, 11b, 11c. In addition, mold materials 11m, 11n, and 11p for attaching members are attached to the floor portion. A bottom plate 112 is attached to the upper surfaces of the mold members 11m and 11n.

  Each of the mold members 11a, 11b,... Is made of an aluminum alloy or the like and has a substantially square cross-sectional outer shape, and a T-shaped groove extending in the longitudinal direction is provided on the surface of each side.

  Brackets 113 are provided at four locations on the outer periphery of the bottom mold members 11i to 11l, and are fixed to the main body frame 2 of the substrate processing apparatus 1 by bolts 114.

  A cover 111 made of a plate material is provided on the outer peripheral surface of the housing 11, but the illustration thereof is omitted except for a part of the cover 111 in the drawing.

  The front cover 111 (not shown) is provided with an opening 112 for transferring the substrate WD by the robot. The opening 112 has such a size that the substrate WD placed in a horizontal state on the hand 5a of the transfer robot 5 can be taken in and out without interfering with the hand 5a.

  The turntable 12 includes a disk-shaped table 121, a rotating shaft 122 that supports the disk-shaped table 121, a bearing that rotatably supports the rotating shaft 122, and the like. A pulley 124 is provided at the lower end portion of the rotating shaft 122, and is driven to rotate via the belt 125 by the output shaft 13 a of the motor 13.

  The surface (upper surface) of the table 121 is finished in a highly accurate surface state so that the substrate WD can be placed with high accuracy. Further, the processing method or material of the surface of the table 121 may be selected according to the type of the substrate WD.

  For the case where the substrate WD can be adsorbed with a negative pressure (vacuum pressure) as in the case where the substrate WD is a semiconductor wafer, a large number of grooves through which air flows are provided on the surface of the table 121. It may be left. In this case, the groove can be constituted by, for example, a large number of concentric grooves and a large number of radially extending grooves for connecting them. Then, holes connected to these grooves may be provided in the center of the disk-shaped table 121 and the rotating shaft 122, and connected to the negative pressure generator via a free coupling and a hose (not shown).

  As the motor 13, a pulse motor, a servo motor or the like is used, and the rotation speed thereof is controlled by the control unit 17 shown in FIG. The motor 13 is provided with a rotation encoder 13b for detecting the rotation speed and the rotation angle position.

  For example, for the A phase and the B phase, the rotary encoder 13b outputs one pulse signal SP every time it rotates a predetermined angle, and outputs N pulse signals SP every time it rotates once. Therefore, Kr × N pulse signals SP are output while the turntable 12, that is, the substrate WD rotates once. Kr is the ratio of the rotational speed of the motor 13 to the rotational speed of the turntable 12. Note that N can be an integer such as 360, 500, 720, or the like.

  The reciprocal 1 / Tsp of the period (time interval) Tsp of the pulse signal SP is proportional to the rotation speed V of the substrate WD, and the rate of change thereof is proportional to the acceleration A of the substrate WD.

  The rotary encoder 13b may be provided on the rotary shaft 122 of the turntable 12 instead of being provided in the motor 13.

  The control unit 17 controls the rotational speed, acceleration (rotational acceleration), rotational angular position (circumferential position), and the like of the motor 13 based on the pulse signal SP output from the rotary encoder 13b. Thereby, the rotation speed V and acceleration (rotation acceleration) A and the rotation angle position of the substrate WD are controlled.

  Note that both the rotational speed V and the acceleration A include positive and negative. That is, “rotational speed V” includes a rotational speed in forward rotation and a rotational speed in reverse rotation, and “acceleration A” includes positive acceleration and negative acceleration (deceleration).

  When the motor 13 is a pulse motor, the rotational speed V, acceleration A, etc. can be controlled by controlling the period, speed, number, etc. of the pulse signals output to the motor 13. .

  The line sensors 14 and 15 have light projecting portions 14a and 15a disposed above and light receiving portions 14b and 15b disposed below, and the brackets 141, 142, 151, and 152 are opposed to each other. Is attached to the housing 11.

  5 to 7 show the positional relationship between the substrate WD and the sensor. FIG. 5 shows an ideal case where the substrate WD is placed at a normal position on the turntable 12. 6 and 7 show an example of an actual arrangement position of the line sensor 14.

  That is, FIG. 6 shows a case where the center position C2 of the substrate WD is deviated from the center position C1 of the turntable 12, which is a normal position. In FIG. 6, the normal position of the substrate WD is indicated by a two-dot chain line, and the actually displaced substrate WD is indicated by a solid line.

  FIG. 7 shows a case where the circumferential position of the substrate WD is deviated from the normal position. In FIG. 7, the center position C2 of the substrate WD coincides with the center position C1 of the turntable 12. However, the rotation angle position, that is, the position of the azimuth display reference NT is only the angle θc with respect to the Y axis where the position is the normal position. There is a gap.

  Further, referring to FIGS. 4 and 9, slit- or strip-shaped laser beams AR1 and AR2 are emitted from light projecting portions 14a and 15a, and light-receiving portions 14b and 15b receive the light. When the substrate WD is placed on the turntable 12, the peripheral portion of the substrate WD is inserted between the light projecting portions 14a and 15a and the light receiving portions 14b and 15b. A part of the light is blocked. Accordingly, the position of the edge EG of the substrate WD is detected based on the output signals S1 and S2 from the light receiving units 14b and 15b.

  The line sensors 14 and 15 are arranged at positions that are approximately 90 degrees apart from each other at the center angle with respect to the center position C1 of the turntable 12 in the plan view shown in FIGS.

  Here, in the plane including the substrate WD, that is, the plane along the upper surface of the turntable 12, the center position C1 of the turntable 12 is the origin, the left-right direction in FIG. 4 is the X axis, and the up and down direction is the Y axis. Define

  Now, the line sensors 14 and 15 constantly monitor the displacement x in the X direction and the displacement y in the Y direction of the edge EG of the substrate WD on the XY plane, respectively. That is, the position (edge position) of the edge EG of the substrate WD is measured (detected) by the line sensors 14 and 15 in real time. In other words, the position of the substrate WD is constantly monitored by the line sensors 14 and 15, and when there is a possibility that the substrate WD falls from the turntable 12 or collides with an internal device, the turntable 12 is immediately stopped. Can do.

  In this specification, the edge position of the substrate WD may be expressed as “edge displacement (x, y)”. Further, the displacement of the edge EG of the substrate WD, particularly the displacement of the edge EG from the reference position (regular position) may be expressed as “edge displacement (x, y)”. The edge displacement (x, y) is also measured (detected) in real time.

  Here, the “reference position” is the position of the edge EG when the substrate WD is placed at the correct position on the turntable 12. That is, the ideal “reference position” is the position of the edge EG when the center position C2 of the substrate WD is placed so as to coincide with the center position C1 of the turntable 12, as shown in FIG.

  However, since it is practically difficult to place the substrate WD so that the center position C2 of the substrate WD completely coincides with the center position C1 of the turntable 12, the substrate WD is set on the turntable 12 in this embodiment. When the error between the center position C2 of the substrate WD and the center position C1 of the turntable 12 is within an allowable range, the position of the edge EG of the substrate WD may be used as the “reference position”.

  Since the position of the edge EG and the center position C2 of the substrate WD can be converted to each other, in this specification, the “reference position of the center position C2” corresponding to the “edge EG reference position” is also “ It will be referred to as “reference position”.

  That is, in the present embodiment, since the displacement of the substrate WD accompanying the rotation of the turntable 12 is a control target, the initial position of the substrate WD or its ideal when the displacement amount, that is, the displacement amount D is a problem. The initial position is treated as the “reference position”.

  The line length of the laser beams AR1 and AR2, that is, the length of the laser beams AR1 and AR2 on the XY plane is, for example, about 3 centimeters. For detection of the edge EG of the substrate WD having a diameter of 30 centimeters, the line sensors 14 and 15 are arranged so that, for example, the center positions of the laser beams AR1 and AR2 are located on the circumferential line having a diameter of 30 centimeters. Be placed.

  The line sensors 14 and 15 are arranged in a state in which the angular positions with respect to the center point of the turntable 12 are shifted from each other by approximately 90 degrees. However, as shown in FIGS. It is arranged at an angular position of 90 + α) degrees. Accordingly, one line sensor 15 is disposed on the X axis, and the other one line sensor 14 is disposed at a position shifted from the Y axis.

  The reason why the line sensor 14 is arranged at a position shifted from the Y axis is as follows. That is, as shown in FIG. 5, the substrate WD is usually provided with an azimuth display reference NT such as a notch or an orientation flat at the peripheral portion or the like in order to display the rotation angle position. When the substrate WD is initially placed on the cassette CA or the turntable 12, in order to simplify control, the orientation display reference NT is often placed on the Y axis. Therefore, when the line sensor 14 is arranged on the Y axis, the line sensor 14 often detects the azimuth display reference NT with the substrate WD initially arranged in order to avoid this. This is to avoid this because it takes time for the preliminary processing.

  Therefore, the angle α is set in the range of more than 0 degree and not more than 45 degrees. However, the angle α should be small enough that the line sensor 14 does not detect it when the azimuth display reference NT is on the Y axis. . For example, the angle α is about 3 degrees or 5 degrees. However, it may be about several degrees to a few dozen degrees or 45 degrees or less. 6 and 7 are shown at about 30 degrees for easy understanding.

  Based on the measured edge displacement (x, y), a center displacement (an eccentric amount) that is a displacement of the center position C2 of the substrate WD from the center position C1 of the turntable 12 can be calculated. Next, a relational expression between the edge displacement (x, y) and the center displacement (X1, Y1) will be described.

  FIG. 8 shows various parameters E to K for obtaining the center displacement (X1, Y1) from the edge displacement (x, y). Using these parameters E to K, the relationship between the edge displacement (x, y) and the center displacement (X1, Y1) can be expressed by the following equations (1) and (2). Note that r is the radius of the substrate WD.

X1 = (K × I / H) −J (1)
Y1 = K − [(E−J) × I / H] (2)
That is, in FIG.
E = r−x
F = (r + y) × sin (α)
G = (r + y) × cos (α)
It is. Also,
H = [(E + F) ² + G ² )] ^1/2 / 2 I = (r ² −H ² ) ^1/2
J = [(E + F) / 2] -F
K = G / 2
Can be shown. Also,
K / H = (J + X1) / I (3)
(E−J) / H = (K−Y1) / I (4)
It is.

  The above formulas (1) and (2) are obtained by transforming the formulas (3) and (4). The parameters E, H, I, J, and K shown in equations (1) and (2) can all be obtained from r, x, y, and α.

  In FIG. 8, the X direction and the Y direction are opposite to those in FIGS. However, since this only changes the sign of the parameter, the center displacement (X1, Y1) in FIGS. 6 and 7 can be obtained using equations (1) and (2).

  Thus, the center displacement (X1, Y1) can be obtained by an arithmetic expression such as a trigonometric function. However, it is also possible to use an appropriate conversion table or the like instead of an arithmetic expression.

  The spot sensor 16 is for detecting an orientation display reference NT provided at a predetermined position on the peripheral edge of the substrate WD, and is attached to the mold member 11e by a bracket 161. On the upper surface of the mold member 11p below the spot sensor 16, a mirror 16a that reflects the spot-like laser light AR3 emitted from the spot sensor 16 is provided. The laser beam AR3 emitted from the spot sensor 16 is reflected by the mirror 16a, and the reflected laser beam is received by the spot sensor 16.

  The laser beam AR3 emitted from the spot sensor 16 is normally blocked by the substrate WD and is not received by the spot sensor 16. However, when the azimuth display reference NT is at the position of the spot sensor 16, the laser beam AR3 is not blocked. The sensor 16 outputs an output signal S3 indicating that the orientation display reference NT has been detected. Based on the output signal S3 and the pulse signal SP from the rotary encoder 13b, the rotational angle position (circumferential position) of the substrate WD is obtained.

  When the azimuth display reference NT is a V-shaped notch having a depth of 1 millimeter, the diameter of the laser beam AR3 may be set to a diameter that can detect this notch.

  The line sensors 14 and 15 and the spot sensor 16 are composed of optical system members and electrical system members (such as amplifiers), and these may be provided separately. In that case, the electrical system member may be attached to an appropriate location in the vicinity of the optical system member in the housing 11, for example.

  In addition, an electromagnetic switching valve 18a for switching on / off of negative pressure supplied to the turntable 12, a pressure sensor 18b for detecting negative pressure, and other necessary members are attached to the housing 11 as necessary.

  9, the control unit 17 includes a first control unit 21, a second control unit 22, a motor control unit 23, a position calculation unit 24, a memory 25, and the like. The second control unit 22 includes a circumferential alignment unit 221, a limit condition detection unit 222, a memory 223, and the like.

  The motor control unit 23 has a drive circuit for rotationally driving the motor 13, a counter for counting the pulse signal SP output from the rotary encoder 13b, and a rotational speed V and an acceleration A corresponding to the input command. And a control circuit for controlling the drive circuit.

  In addition, the motor control unit 23 includes a memory that stores various setting values for the rotation speed V and the acceleration A in order to control the rotation speed V and acceleration A of the turntable 12 by controlling the motor 13. These set values are set by a user input operation from the operation unit 32. Further, the set value can be automatically set or automatically changed and set by a program stored in the memory of the motor control unit 23 in advance. According to this, the rotation speed V and acceleration A of the turntable 12 can be automatically set and controlled based on a program stored in advance.

  Based on the output signals S1 to S3 from the line sensors 14 and 15 and the spot sensor 16, the position calculation unit 24 obtains the position of the substrate WD on the XY plane, the position in the circumferential direction, or their displacement or displacement amount. For example, the position calculation unit 24 calculates the position on the XY plane or the center displacement that is the displacement from the edge displacement (x, y) measured by the line sensors 14 and 15 based on the above formulas (1) and (2). An operation for obtaining (X1, Y1) is performed.

  In the present embodiment, since the control operation in the control unit 17 is mainly performed on the center displacement (X1, Y1), the position calculation unit is based on the edge displacement (x, y) measured by the line sensors 14, 15. 24 may express the entire process of obtaining the center displacement (X1, Y1) as "measurement (or detection) of the center displacement (X1, Y1) by the line sensors 14, 15".

  Further, as described above, since the edge displacement (x, y) and the center displacement (X1, Y1) can be mutually converted, in the present specification, these are referred to as “displacement C” or “displacement amount”. D ”. Further, the edge displacement (x, y) or the center displacement (X1, Y1) may be expressed as “displacement amount D” particularly when the difference between them and their reference position is a problem.

  Further, “displacement C” and “displacement amount D” include the displacement or displacement amount of the rotation angle position of the substrate WD.

  The function constituted by the line sensors 14 and 15, the spot sensor 16, and the position calculation unit 24 is an example corresponding to the “substrate position detection means” in the present invention.

  The control unit 17 can be realized by a computer including a CPU, a memory, an interface circuit, other peripheral circuits, a hardware circuit, and the like. When the program is executed by the CPU, the first control unit 21 and the second control unit 22 are provided.

  The first control unit 21 performs various known controls for aligning the substrate WD, which is the original function of the alignment apparatus 6.

  For example, the first control unit 21 detects the position of the substrate WD at a different rotation angle position of the substrate WD by rotating the rotation table 12 by the motor 13 while the substrate WD is placed on the rotation table 12. A first displacement amount D1 for the alignment is obtained.

  At that time, the motor control unit 23 controls the rotational speed V and acceleration A of the turntable 12 so as not to exceed the maximum rotational speed Vmax and maximum acceleration Amax stored in the memory 25. Further, the rotational speed V and acceleration A to be set may be modified according to the environmental state at that time.

  The second control unit 22 performs control necessary for setting the maximum rotation speed Vmax and the maximum acceleration Amax of the turntable 12 during alignment in order to realize the rotation condition adjustment method of the present invention.

  For example, the second control unit 22 rotates the turntable 12 at various rotational speeds V or accelerations A different from each other by the motor 13 while the substrate WD is placed on the turntable 12. Accordingly, the second displacement amount D2 caused by the displacement of the substrate WD with respect to the turntable 12 is measured. Then, the rotational speed V or acceleration A when the second displacement amount D2 exceeds the threshold th1 or immediately before is obtained as the limit speed Va or limit acceleration Aa, and this is recorded in the memory 223. Further, the obtained limit speed Va and limit acceleration Aa are displayed on the display device 31.

  Based on the determined limit speed Va and limit acceleration Aa, the maximum rotation speed Vmax and the maximum acceleration Amax for rotation of the turntable 12 when the first control unit 21 determines the first displacement amount D1 are determined. By recording this in the memory 25, the maximum rotation speed Vmax and the maximum acceleration Amax of the turntable 12 are set.

  More specifically, for example, the second control unit 22 performs the first step of rotating the turntable 12 by the motor 13 while the substrate WD is placed on the turntable 12, and the rotation of the turntable 12. The second step of detecting the second displacement amount D2 caused by the displacement of the substrate WD with respect to the turntable 12 by the substrate position detecting means, and whether or not the second displacement amount D2 exceeds the threshold value th1. When the second displacement amount D2 exceeds the threshold value th1, the rotational speed V or acceleration A at or immediately before the third step is determined as the limit speed Va or limit for alignment. When the fourth step obtained as the acceleration Aa and recorded in the memory 223 and the second displacement D2 does not exceed the threshold th1, the set value of the rotational speed V or acceleration A of the turntable 12 is increased. A fifth step of repeating the first to third step Te, to run.

  In the fourth step, as the immediately preceding rotation speed V and acceleration A, the rotation speed V and acceleration A when the second displacement amount D2 does not exceed the threshold th1 may be used.

  For example, the rotation speed V and acceleration A when the fourth step was executed last time (one time before), the rotation speed V and the acceleration A when the fourth step was executed last time (two times before), and the current time Finally, when the rotation speed or acceleration obtained by subtracting the predetermined rotation speed or acceleration from the rotation speed V or acceleration A when the fourth step is executed, or the second displacement amount D2 does not exceed the threshold th1. It is possible to use the rotation speed V and acceleration A of

  Further, when the second displacement amount D2 is measured by continuously rotating the turntable 12, the substrate between the execution of the fourth step last time and the execution of the fourth step this time is performed. WD may have shifted. Therefore, the rotational speed V and acceleration A at any timing or predetermined timing in the meantime can be set to the immediately preceding rotational speed V and acceleration A. In other words, the rotational speed V and the acceleration A at any timing between the timing at which the second displacement amount D2 was measured not to exceed the threshold th1 and the timing at which it was measured to be exceeded, The immediately preceding rotation speed V and acceleration A can be set. In this case, the timing just before the time tg when the second displacement amount D2 exceeds the threshold th1 may be set as the immediately preceding timing, and the time tg may be set by the user.

  Note that the rotation of the turntable 12 may be stopped at an appropriate timing after the limit speed Va or the limit acceleration Aa is recorded in the memory 223 in the fourth step.

  Then, based on the limit speed Va and the limit acceleration Aa, the maximum rotation speed Vmax and the maximum acceleration Amax of the turntable 12 in the alignment device 6 are set. In this case, as a method for obtaining the maximum rotation speed Vmax and the maximum acceleration Amax, the limit speed Va or the limit acceleration Aa is set to the same value, or the limit speed Va or the limit acceleration Aa is multiplied by a predetermined ratio, or the limit A value obtained by subtracting a predetermined value from the speed Va or the limit acceleration Aa, or a value obtained by calculating a function having the limit speed Va or the limit acceleration Aa as a variable, or the maximum rotational speed Vmax corresponding to the limit speed Va or the limit acceleration Aa Alternatively, various methods such as a value read from a table in which the maximum acceleration Amax is recorded can be adopted.

  When alignment is performed by the alignment device 6, the rotational speed V and the acceleration A are set within a range not exceeding the set maximum rotational speed Vmax and maximum acceleration Amax. Such a rotation speed V and acceleration A may be set by the user or may be set automatically.

  When the user sets, it may be set such that setting exceeding the maximum rotation speed Vmax and the maximum acceleration Amax is impossible. In the case of automatic setting, for example, it may be set as a predetermined ratio with respect to the maximum rotation speed Vmax and the maximum acceleration Amax. For example, assuming that the predetermined ratio is 100%, the maximum rotation speed Vmax and the maximum acceleration Amax may be set as the actual rotation speed V and acceleration A of the turntable 12 when performing alignment.

  As will be described later, the second displacement amount D2 is equal to the difference ΔB (= B2−B1) between the detected value B2 and the initial value B1 for the center displacement (X1, Y1). Then, in determining whether or not the second displacement amount D2 exceeds the threshold value th1, for example, for each of X1 and Y1, it is checked whether or not the threshold value th11 or the threshold value th12 is exceeded. In this case, when any one of X1 and Y1 exceeds the threshold value th11 or the threshold value th12, it is determined that the second displacement amount D2 exceeds the threshold value th1.

  Further, in the first step, the turntable 12 is intermittently rotated for every one rotation, and in the second step, the second displacement amount D2 is detected every time one turn of the turntable 12 is completed. Can be done.

  That is, in this case, every time the turntable 12 is rotated once, the second displacement amount D2 is measured, the set value of the rotation speed V or the acceleration A is increased stepwise, and the next turntable 12 is rotated once. The rotation and the measurement of the second displacement amount D2 are performed. This corresponds to the stepwise speed increase method described later.

  In that case, in the first step, every time the turntable 12 is rotated once, the rotation starts from the stop state and increases at the set positive acceleration. After the rotation speed reaches the set value, the setting is made. It is possible to decelerate and stop at the negative acceleration (deceleration).

  Further, in the fifth step, the set value of the acceleration A can be made constant and the set value of the rotation speed V can be increased.

  Further, in the fifth step, the set value of the rotation speed V can be made constant and the set value of the acceleration A can be increased.

  In the first step, the turntable 12 is continuously rotated. In the second step, the second displacement amount D2 is detected at a predetermined time interval. In the fifth step, the rotation speed V is detected. The set value can be increased with a predetermined inclination.

  That is, in this case, the rotational speed V of the turntable 12 is gradually increased, and the second displacement amount D2 is detected at predetermined time intervals in the process. This corresponds to the continuous speed increase method described later.

  In addition, you may perform so that either of the 1st-4th steps above may mutually overlap in time.

The control unit 17 can exchange signals with the control device 7 and can align the substrate WD in cooperation with the transfer robot 5.
[Explanation of control operation by timing diagram]
Next, the control operation of the second control unit 22 will be described in more detail with reference to FIGS. The control operation of the second control unit 22 includes preliminary processing, circumferential alignment processing (notch alignment processing), and limit condition measurement processing.

First, preliminary processing by the second control unit 22 will be described. The preliminary processing includes notch removal processing and initial placement processing.
[Notch removal treatment in preliminary treatment]
The notch removal process is a process for preventing the orientation display reference NT of the substrate WD placed on the turntable 12 from being applied to the laser beams AR 1 and AR 2 of the line sensors 14 and 15.

  First, the substrate WD to be used is placed on the turntable 12. This may be performed using the transfer robot 5 or may be performed manually by the user. In that case, the substrate WD is placed so as to coincide with the center position of the turntable 12 as much as possible.

  Then, the edge displacement (x, y) is measured by the line sensors 14 and 15. Thereafter, the turntable 12 is rotated by a slight angle β, and the edge displacement (x, y) is measured again by the line sensors 14 and 15.

  When the difference between these two measured edge displacements (x, y) is within an allowable range, it is determined that the laser light AR1, AR2 is not applied with the azimuth display reference NT. The allowable range in this case is, for example, within 0.3 millimeters for each difference between x and y.

  When the difference between the two measured edge displacements (x, y) is outside the allowable range, that is, when the difference between any of x and y exceeds the allowable range, the laser beams AR1 and AR2 are oriented. Since the display standard NT may be applied, in order to avoid this, the turntable 12 is rotated by a predetermined angle β and the edge displacement (x, y) is measured again.

  Note that the angle β may be set to about the center angle corresponding to the maximum circumferential length of the orientation display reference NT. For example, the angle β may be set to about 3 degrees.

  When the edge displacement (x, y) is measured again within the allowable range, the notch removal process is terminated.

Thus, the notch removal process is performed by repeatedly performing the rotation of the angle β and the detection of the edge position. By performing the notch removal process, the subsequent measurement of the edge displacement (x, y) by the line sensors 14 and 15 is accurately performed.
[Initial placement processing in preliminary processing]
Next, initial arrangement processing is performed. The initial placement process is a process for placing the substrate WD at the correct position on the turntable 12 (initial placement). That is, it is determined whether the error between the center position C2 of the substrate WD and the center position C1 of the turntable 12 is within an allowable error range. If it is determined that the error is outside the error range, the substrate WD is disposed. cure.

  First, after the notch removal processing is completed, the edge displacement (x, y) is measured and determined by the line sensors 14 and 15. Here, the displacement in the X direction and the Y direction from the edge position (reference position) when the center position C2 of the substrate WD coincides with the center position C1 of the turntable 12 is obtained as the edge displacement (x, y). It is done. That is, when the substrate WD is placed at the correct position on the turntable 12, the edge displacement (x, y) is 0, that is, x = 0 and y = 0.

  When the edge displacement (x, y) is within the error range, that is, when both x and y are within the error range, the determination of the initial position is good. The error range in this case is, for example, within 0.2 mm for each difference between x and y.

  If the edge displacement (x, y) is outside the error range, that is, if any of x and y is outside the error range, the determination of the initial position is denied and the substrate is determined until the initial position is determined to be good. The rearrangement of the WD and the measurement and determination of the edge displacement (x, y) are repeated. When the substrate WD is rearranged, the notch removal process described above is first performed.

  Note that the edge displacement (x, y) measured at the end of the notch removal processing can be used as the edge displacement (x, y) used for the determination in the initial placement processing.

  Further, for the determination in the initial arrangement process, for example, the turntable 12 may be rotated once, and a plurality of edge displacements (x, y) measured during the rotation may be used. In this case, for example, when all of the plurality of edge displacements (x, y) are within the error range, the initial position may be determined as good. Alternatively, when the maximum difference between the plurality of edge displacements (x, y) is within the error range, the initial position may be determined as good.

  The rearrangement of the substrate WD may be performed using the transfer robot 5 or may be performed manually by the user.

When the determination of the initial position of the substrate WD becomes good, the edge displacement (x, y) at that time or the center displacement (X1, Y1) based on it may be used as the reference position.
[Circumferential alignment processing (notch alignment processing)]
Next, the circumferential direction alignment process by the second control unit 22 will be described. The circumferential alignment process is mainly performed by the control of the circumferential alignment unit 221.

  As shown in FIG. 10, at the time t1, the motor 13 rotates the turntable 12 in the forward direction (for example, in the right direction). The rotational speed V increases with a constant acceleration A, and reaches a constant rotational speed V1 at time t2. When an output signal S3 indicating that the azimuth display reference NT is detected is output from the spot sensor 16 at time t3, the vehicle decelerates at a constant negative acceleration (deceleration) A so as to stop the rotation of the motor 13. At the time t4, the rotation speed V becomes 0, and thereafter, it rotates in the reverse direction (for example, leftward) at the negative rotation speed V. At time t5, a constant low rotational speed V2 is obtained, and at time t6, an output signal S3 indicating that the azimuth display reference NT is detected is output from the spot sensor 16. Thereby, the rotation of the motor 13 is stopped.

  That is, when the azimuth display reference NT is detected at time t3, the substrate WD cannot be stopped instantaneously, and therefore stops after the azimuth display reference NT passes the position of the laser beam AR3 of the spot sensor 16. Between time t4 and time t6, reverse rotation is performed at a low rotational speed V2 at which instantaneous stop is possible, and the turntable 12 stops when the azimuth display reference NT is detected again. As a result, the position of the laser beam AR3 of the spot sensor 16 and the position of the orientation display reference NT coincide with each other, and the rotation angle position (position in the circumferential direction) of the substrate WD is positioned at the origin position.

After aligning the origin of the substrate WD in the circumferential direction in this manner, the substrate WD is rotated in the forward direction from time t7, decelerated so as to stop at a position rotated by a predetermined rotation angle θa from the origin, and at time t8. Stop. As a result, the substrate WD is positioned at a predetermined rotation angle θa in the circumferential direction.
[Limit condition measurement processing]
Next, control for detecting the limit speed Va and limit acceleration Aa by the second control unit 22 will be described. This control is mainly performed by the limit condition detection unit 222.
[Control of detection of limit speed Va]
First, control for detecting the limit speed Va will be described.

  In the control of the detection of the limit speed Va, first, the position of the edge EG of the substrate WD is detected by the line sensors 14 and 15 in the state where the alignment processing in the circumferential direction of the substrate WD is completed. As described above, the position of the edge EG can be detected as an edge displacement (x, y) from the reference position, for example. The detected position (edge displacement) of the edge EG is stored in the memory 223 as the initial value B1.

  In the present embodiment, the center displacement values X1 and Y1 are used as the initial value B1, but the edge displacement values x and y can also be used.

Thereafter, the limit speed Va is detected while increasing the rotation speed V of the turntable 12 (that is, the substrate WD). As described above, the control method for increasing the rotation speed V is stepwise. There are speed increasing methods and continuous speed increasing methods. Each will be described below.
[Stepwise speed increase method]
In the stepwise speed increasing method, the rotation speed V of the turntable 12 is increased stepwise for each round of rotation, and at each turn, the rotation of the turntable 12 and the second displacement amount D2 (this is a difference ΔB). And the second displacement amount D2 is checked whether it exceeds the threshold th.

  That is, in FIGS. 11 and 12, in the first check, at time t11e, the turntable 12 is accelerated at a constant acceleration As set from the stop state, and when the rotation speed V reaches the set value Vcmin, the rotation is continued for a while. It is rotated at a speed V, then decelerated at a constant negative acceleration (−A), and stopped at a position rotated once (360 degrees) (time t12). After the turntable 12 stops, the center displacement (X1, Y1) of the substrate WD is detected, and this is set as a detection value B2. A difference ΔB (= B2−B1) between the detection value B2 and the initial value B1 described above is obtained. The obtained difference ΔB is the second displacement amount D2. It is checked whether or not the difference ΔB (second displacement amount D2) exceeds the threshold value th1. This completes the first check. When the difference ΔB does not exceed the threshold value th1, a second check is performed.

  In the second check, at the time t12e, the rotation speed V is accelerated from the state of 0 at the same constant acceleration As as in the first time, and when the rotation speed V reaches the set value (Vcmin + ΔV), the rotation speed V is rotated for a while. Thereafter, the vehicle is decelerated at the same negative acceleration (−A) as in the first time, and stops at a position rotated once (time t13). After the turntable 12 stops, the position of the edge EG of the substrate WD is detected, and this is set as a detection value B2. A difference ΔB between the detected value B2 and the initial value B1, that is, a second displacement amount D2 is obtained. It is checked whether the difference ΔB does not exceed the threshold value th1. This completes the second check. When the difference ΔB does not exceed the threshold value th1, the third, fourth,.

  In the n-th check, the rotation speed V is set to [Vcmin + (n−1) · ΔV], and the turntable 12 is similarly rotated once to obtain the difference ΔB. The difference ΔB exceeds the threshold th1. Check for any.

  Then, when the set value [Vcmin + (n−1) · ΔV] of the rotation speed V reaches the maximum rotation speed Vcmax, the process ends.

  When the difference ΔB exceeds the threshold th1 in the n-th check, the (n−1) -th rotation speed V that is the previous time or the previous time is set as the limit speed Va, and this is stored in the memory 223. Record. When the difference ΔB exceeds the threshold value th1, the subsequent check is not performed.

  In this way, the set value of the rotational speed V is increased stepwise from the minimum rotational speed Vcmin to the maximum rotational speed Vcmax by a slight rotational speed (increase in rotational speed V) ΔV each time, and measurement is performed each time. It is checked whether or not the difference ΔB obtained by the above does not exceed the threshold value th1. During this time, the set value of the acceleration A for each time is set to a constant set value As. The set value As may be a low value that does not cause the substrate WD to shift.

It should be noted that any of the following methods (1) and (2) may be adopted in checking whether the difference ΔB exceeds the threshold th1.
(1) X1 and Y1 of the measured center displacement are independently used as the difference ΔB, and X1 and Y1 are individually compared with the respective threshold values th1x and th1y and checked. In this case, for example, when the threshold value th1x or th1y is exceeded for either X1 or Y1, it may be determined that the difference ΔB has exceeded the threshold value th1.
(2) The movement distance (straight line distance) of the center position C2 of the substrate WD is obtained based on the measured center displacements X1 and Y1, and the obtained movement distance is used as the difference ΔB. In this case, the difference ΔB, which is the movement distance, may be checked by comparing it with the threshold value th1.

  The minimum rotation speed Vcmin and the maximum rotation speed Vcmax can be set by the user operating the operation unit 32. At that time, the range may be set in consideration of the range in which the rotation of the motor 13 can be controlled and the range of the rotational speed V at which the substrate WD is likely to be displaced.

  The increment ΔV of the rotation speed V for each time can be set by the user in the same manner. Further, it is possible to increase the amount of increase ΔV having the same size every time, but it is also possible to add the amount of increase ΔV having a different size every time.

  For example, an increment ΔV of a predetermined ratio with respect to the previous rotational speed V, that is, a value obtained by multiplying the previous rotational speed V by a predetermined ratio Kv (V × Kv) for each time may be used as the increment ΔV. Is possible. In this case, the rotational speed V is increased by a predetermined ratio Kv each time. For example, it can be increased by 5 percent or 10 percent.

  As the rotational speed V increases, the time required for one rotation of the turntable 12 is shortened. Therefore, the time required for one turn of the turntable 12 is shorter in the second check than in the first check. The third check is shorter than the check.

  As described above, when the user operates the operation unit 32, it is possible to set a constant value or set a predetermined ratio Kv as the increment ΔV of the rotation speed V each time. Further, as described above, the increment ΔV of the rotational speed V or the rotational speed V itself can be automatically set by a program stored in advance.

Note that the number N of pulse signals SP in one rotation is the same regardless of how the rotation speed V and acceleration A are set. That is, by controlling the rotation speed V and the acceleration A, the generation interval and distribution with respect to the time axis of the N pulse signals SP for one rotation are controlled.
[Control of detection of limit acceleration Aa]
Next, detection control of the limit acceleration Aa will be described.

  In the control for detecting the limit acceleration Aa, in the control for detecting the limit speed Va described above, the rotation speed V is set to a constant rotation speed Vs, and the acceleration A is increased step by step for each round rotation.

  That is, in FIG. 13, in the first check, at time t22e, the turntable 12 starts rotating from the stopped state with the initially set acceleration Acmin, and after reaching the set rotation speed Vs, the same magnitude is obtained. The vehicle is decelerated with a negative acceleration (-Acmin) and stops at a position where it has rotated once (time t22). After the turntable 12 is stopped, the center displacement (X1, Y1) of the substrate WD is detected as in the case of detecting the limit speed Va, and this is set as a detection value B2. A difference ΔB (= B2−B1) between the detection value B2 and the initial value B1 is obtained, and it is checked whether or not the obtained difference ΔB exceeds the threshold value th1.

  In the second check, at time t22e, from the state where the rotational speed V is 0, the value (Acmin + ΔA) obtained by adding the increase ΔA to the first acceleration Acmin is set as the acceleration A setting value, and rotation is started. Thereafter, after reaching the set rotational speed Vs, the vehicle is decelerated at the same negative acceleration [− (Acmin + ΔA)] and stops at a position where it has rotated once (time t23). After the turntable 12 stops, as in the first time, the center displacement (X1, Y1) of the substrate WD is detected, and this is set as a detection value B2. A difference ΔB (= B2−B1) between the detection value B2 and the initial value B1 is obtained, and it is checked whether or not the obtained difference ΔB exceeds the threshold value th1. When the difference ΔB does not exceed the threshold value th1, the third, fourth,.

  In the n-th check, the set value of the acceleration A is set to [Acmin + (n−1) · ΔA], and the turntable 12 is similarly rotated once to obtain the difference ΔB, and the difference ΔB does not exceed the threshold th1. Check whether or not.

  Then, when the set value [Acmin + (n−1) · ΔA] of the acceleration A reaches the maximum acceleration Acmax, the process ends.

  In the n-th check, when the difference ΔB exceeds the threshold th1, the (n−1) -th acceleration A that time or immediately before is set as the limit acceleration Aa, and this is recorded in the memory 223. To do. When the difference ΔB exceeds the threshold value th1, the subsequent check is not performed.

  As the acceleration A increases, the time required for one rotation of the turntable 12 is shortened. Therefore, the time required for one rotation of the turntable 12 is shorter in the second check than in the first check. The third check is shorter than the check.

  As described above, the set value of the acceleration A is gradually increased from the minimum acceleration Acmin to the maximum acceleration Acmax by a small amount of acceleration (an increase in the acceleration A) ΔA step by step, and the difference obtained by each measurement. It is checked whether or not ΔB exceeds the threshold value th1. During this time, the set value of the rotational speed V for each time is set to a constant set value Vs. The set value Vs may be set to a low value that does not cause the substrate WD to shift.

  Note that the minimum acceleration Acmin and the maximum acceleration Acmax are set by the user in consideration of, for example, the range in which the rotation of the motor 13 can be controlled and the range of the acceleration A in which the substrate WD is likely to be displaced.

  The increase ΔA of the acceleration A for each time can be similarly set by the user. Further, it is possible to add and increase an increase ΔA of the same size every time, to add an increase ΔV of a different size every time, or to increase by a predetermined ratio Ka every time. is there. Further, the increase ΔA of the acceleration A or the acceleration A itself can be automatically set by a program stored in advance.

  As described above, the limit speed Va and the limit acceleration Aa can be detected.

  Further, when the limit speed Va or the limit acceleration Aa is detected, the set values As and Vs of the respective acceleration A or the rotation speed V are variously changed, and the limit speeds for the different acceleration Aa or the rotation speed Vs which are set differently. Va and limit acceleration Aa may be detected.

  For example, in the control of the detection of the limit speed Va, it is possible to obtain the optimum combination of the limit speed Va and the limit acceleration Aa by detecting the limit speed Va for various different accelerations As.

On the contrary, in the detection control of the limit acceleration Aa, the optimum combination of the limit speed Va and the limit acceleration Aa can be similarly detected by detecting the limit acceleration Aa for various different rotation speeds Vs. It is possible to ask.
[Continuous speed increase method]
In the continuous speed increasing method, the rotational speed V of the turntable 12 is gradually increased gradually at a predetermined inclination (acceleration), the second displacement amount D2 is detected at a predetermined time interval therebetween, and the second It is checked whether or not the displacement amount D2 does not exceed the threshold value th.

  That is, as shown in FIG. 14, the set value of the rotational speed V of the turntable 12 (substrate WD) is continuously increased from the minimum rotational speed Vcmin to the maximum rotational speed Vcmax. In this case, “continuous” does not necessarily have to be strictly continuous. For example, in digital control, it is stepwise from the microscopic viewpoint, but this is also included in the “continuous” here.

  In the meantime, the second displacement amount D2 is detected at predetermined time intervals. That is, when the rotation is stopped or when the rotation is the minimum rotation speed Vcmin, the center displacement (X1, Y1) of the substrate WD is detected and set as the initial value B1. Then, the center displacement (X1, Y1) is detected at a predetermined time interval to obtain a detection value B2. Every time the detection value B2 is detected, a difference ΔB (= B2−B1) between the detection value B2 and the initial value B1 is obtained. The obtained difference ΔB is the second displacement amount D2. It is checked whether or not the difference ΔB exceeds the threshold value th1. When the threshold value th1 is exceeded, the immediately preceding rotational speed V is set as the limit speed Va, and this is recorded in the memory 223.

  When the maximum rotational speed Vcmax is reached without exceeding the threshold value th1, the process ends.

Note that a preset time interval may be used as the time interval (predetermined time interval) for detecting the second displacement amount D2. Alternatively, the second displacement amount D2 may be detected every time the turntable 12 rotates by a predetermined angle using the pulse signal SP output from the rotary encoder 13b.
[Limit condition table]
When the limit speed Va and the limit acceleration Aa are obtained as described in FIGS. 11 to 14, the limit speed Va and the limit acceleration Aa together with the identification code SB of the substrate WD that has been checked are shown in FIG. Recorded in the table TB1.

  That is, such rotation condition adjustment by the second control unit 22 is performed on a plurality of substrates WD having different types and lot numbers, and the limit speed Va and the limit acceleration Aa obtained as a result of each adjustment are obtained from the substrate WD. The identification code SB for identifying the type and lot number is recorded in the limit condition table TB1.

  FIG. 15 shows an example of the limit condition table TB1. The limit condition table TB1 is stored in the memory 223.

  As described above, the critical speeds Va1, 2, 3... And the critical accelerations Aa1, 2, 3,... Record in the limit condition table TB1.

When the control for alignment is performed by the first control unit 21, the limit speed Va and the limit acceleration Aa for the substrate WD to be aligned are read from the limit condition table TB1, and the read limit speed Va is read. The maximum rotation speed Vmax and the maximum acceleration Amax are obtained based on the limit acceleration Aa and set in the memory 25.
[Effects of this embodiment]
In this way, when the first control unit 21 obtains the first displacement amount D1 for alignment, the optimum rotational speed V and acceleration A that do not cause the substrate WD to slip are easily measured in a short time. Will be set.

  Therefore, according to the alignment apparatus 6 of the present embodiment, the time required for the control for alignment can be significantly reduced. For example, the alignment apparatus 6 according to the present embodiment has conventionally required about one hour or several hours for adjustment for obtaining the rotational speed V and acceleration A so as not to slip for one substrate WD. It is possible to carry out in a few minutes to a few minutes.

  In particular, if only the limit speed Va is detected, adjustment can be performed in a short time of about several seconds by using the continuous speed increasing method described above. Actually, when the substrate WD is set on the turntable 12, the center positions C1 and C2 hardly coincide with each other. Therefore, the position of the substrate WD is often shifted due to the centrifugal force caused by the rotation. Therefore, it is practically useful to set the acceleration A as an appropriate set value As and obtain the limit speed Va by the continuous speed increasing method.

In addition, since the optimum rotation speed V and acceleration A of the turntable 12 can be set when performing alignment, the time required for alignment can be minimized.
[Modification of this embodiment]
In the embodiment described above, the detection of the critical speed Va and the critical acceleration Aa may be performed immediately before the alignment of the substrate WD, or may be performed in advance at the time when the substrate WD is provided. The table TB1 may be created in advance.

  In the various controls described above, when the position of the azimuth display reference NT is known by performing detection by the spot sensor 16, the above-described notch removal process can be omitted.

  In the present embodiment, since the two line sensors 14 and 15 are used, the substrate WD is used when the laser beams AR1 and AR2 of these line sensors 14 and 15 are not on the position of the orientation display reference NT. The edge displacement (x, y) and the center displacement (X1, Y1) can be detected without rotating. Therefore, when the substrate WD is rotated, the edge displacement (x, y) and the center displacement (X1, Y1) of the substrate WD are detected in real time with respect to the instantaneous rotational speed V during rotation. be able to.

  Accordingly, instead of detecting the center displacement (X1, Y1) for every one rotation as described in FIG. 14, the rotation speed V or its set value is continuously changed while rotating the turntable 12. It is possible to detect the second displacement amount D2 in real time for each predetermined appropriate rotation angle.

  When the limit speed Va and the limit acceleration Aa are recorded in the limit condition table TB1, the edge displacement (x, y) or the center displacement (X1, Y1) at that time may also be recorded in the limit condition table TB1. .

Further, a plurality of different threshold values th1, 2, 3,... Are set, and a limit speed Va or a limit acceleration Aa or the like when each threshold value th is exceeded is obtained and stored in the limit condition table TB1. It may be recorded. In this way, when the control for alignment is performed, the rotational speed V and acceleration A of the turntable 12 can be set more finely.
[Explanation of control operation by flowchart]
Next, the control operation by the control unit 17 will be described with reference to the flowcharts shown in FIGS. 19 and 20 are examples of the stepwise speed increasing method, and FIG. 21 is an example of the continuous speed increasing method.

  In FIG. 16, first, the adjustment of the rotation condition for alignment, that is, the detection of the limit speed Va and the limit speed Va, and the setting of the maximum rotation speed Vmax and the maximum acceleration Amax based on it are performed (# 1). A displacement amount for alignment is measured (# 2).

  In FIG. 17, in the adjustment of the rotation conditions, preliminary processing is performed (# 11), alignment of the substrate WD in the circumferential direction is performed, and positioning is performed at a predetermined rotation angle θa (# 12). Then, the limit speed Va is detected (# 13), the limit acceleration Aa is detected (# 14), and these are set as rotation conditions (# 15).

  In FIG. 18, in the preliminary process, first, the substrate WD is set on the turntable 12 (# 21). The displacement of the substrate WD is measured (detected) (# 22), the turntable 12 is rotated by a predetermined angle β (# 23), and the displacement of the substrate WD is measured again (# 24). The rotation of the angle β and the measurement of the displacement are repeated until the difference between the two displacements measured twice is within the allowable range (No in # 25).

  When the difference in displacement is within the allowable range (Yes in # 25), the displacement amount at that time is measured (# 26), and it is determined whether the displacement amount is within the error range (# 27). If the displacement exceeds the error range (No in # 27), after the user or the transfer robot 5 resets the substrate WD (# 28), Step # 22 and subsequent steps are executed again.

  If the displacement amount is within the error range (Yes in # 27), the process returns.

  In FIG. 19, in detecting the limit speed, first, the acceleration As is set (# 31), the initial value of the rotation speed V is set (# 32), and the turntable 12 is rotated (# 33). The substrate WD is rotated by the rotation of the turntable 12, and the second displacement amount D2 caused by the displacement of the substrate WD with respect to the turntable 12 is measured (# 34). The second displacement amount D2 is compared with the threshold value th1, and it is determined whether or not the second displacement amount D2 exceeds the threshold value th1 (# 35).

  If the second displacement amount D2 exceeds the threshold th1 (Yes in # 35), the rotational speed V of the turntable 12 at that time or the rotational speed V immediately before it is obtained as the limit speed Va and stored in the memory 223. Recording is performed, and the rotation of the turntable 12 is stopped (# 36). In step # 36, the limit speed Va and the second displacement amount D2 may be displayed on the display device 31.

  When the second displacement amount D2 does not exceed the threshold value th1 (No in # 35), the set value of the rotational speed V of the turntable 12 is increased (# 37), and Steps # 33 to 35 are repeated. At this time, if the set value of the rotational speed V becomes equal to or higher than the maximum rotational speed Vcmax (Yes in # 38), the process is terminated after proceeding to Step # 36.

  If the answer is YES in step # 38, the display device 31 may display that the maximum rotational speed Vcmax has been reached and the rotation of the turntable 12 may be stopped without proceeding to step # 36. .

  In the flowchart of FIG. 19, steps # 33, 34, 35, 36, and 37 are examples corresponding to steps 1, 2, 3, 4, and 5 of the present invention.

  In FIG. 20, in detecting the limit acceleration, first, the rotational speed Vs is set (# 41), the initial value of the acceleration A is set (# 42), and the turntable 12 is rotated (# 43). The substrate WD is rotated by the rotation of the turntable 12, and the second displacement amount D2 caused by the displacement of the substrate WD with respect to the turntable 12 is measured (# 44). The second displacement amount D2 is compared with the threshold value th1, and it is determined whether or not the second displacement amount D2 exceeds the threshold value th1 (# 45).

  When the second displacement D2 exceeds the threshold th1 (Yes in # 45), the acceleration A of the turntable 12 at that time or the acceleration A immediately before it is obtained as the limit acceleration Aa and recorded in the memory 223. Then, the rotation of the turntable 12 is stopped (# 46). The limit acceleration Aa may be displayed on the display device 31.

  When the second displacement amount D2 does not exceed the threshold th1 (No in # 45), the set value of the acceleration A of the turntable 12 is increased (# 47), and Steps # 43 to 45 are repeated. At this time, if the set value of the acceleration A becomes equal to or greater than the maximum acceleration Acmax (Yes in # 48), the process is terminated after proceeding to Step # 46.

  In addition, when it becomes YES in step # 48, it may display on the display apparatus 31 that it became more than the maximum acceleration Acmax, without shifting to step # 46, and rotation of the turntable 12 may be stopped.

  In the flowchart of FIG. 20, steps # 43, 44, 45, 46, and 47 are examples corresponding to steps 1, 2, 3, 4, and 5 of the present invention.

  In FIG. 21, in the limit speed detection of another embodiment, the initial value B1 of the displacement of the set substrate WD is acquired (# 51). The substrate WD is rotated by a predetermined angle (# 52), and the displacement after rotation is acquired as the detection value B2 (# 53).

  The detected value B2 and the initial value B1 are compared to determine the difference ΔB (second displacement D2) (# 54), and it is checked whether or not the difference ΔB exceeds the threshold th1 (# 54). # 55).

  When the difference ΔB exceeds the threshold value th1 (Yes in # 55), the rotational speed V at that time or the rotational speed V immediately before it is set as the limit speed Va, which is stored in the memory 223, and is displayed on the display device 31. (# 56) and the rotation of the turntable 12 is stopped (# 57).

  If the difference ΔB does not exceed the threshold th1 in step # 55, the set value of the rotational speed V is increased (# 58), and the process returns to step # 52. At this time, if the set value of the rotational speed V becomes equal to or higher than the maximum rotational speed Vcmax (Yes in # 59), the process is terminated after proceeding to Step # 56.

  In the embodiment described above, the configuration, structure, arrangement, control content, etc. of each part of the transfer robot 5, the alignment device 6, the control device 7, and the substrate processing apparatus 1 are various other than those described above. Is possible.

  In the embodiment described above, the structure and shape of the housing 11, the configuration for rotationally driving the turntable 12, the types and attachment methods of the line sensors 14 and 15 and the spot sensor 16, the first control unit 21 and the second control. The details of the control of the unit 22, the configuration, the structure, the shape, the number, the arrangement, the circuit, the control timing or the order of the whole or each part of the alignment apparatus 6 can be appropriately changed in accordance with the gist of the present invention.

  For example, in the embodiment described above, two line sensors 14, 15 are used, but three or more line sensors may be used.

DESCRIPTION OF SYMBOLS 1 Substrate processing apparatus 6 Alignment apparatus 11 Housing 12 Turntable 13 Motor (drive means)
14,15 Line sensor (Substrate position detection means)
16 Spot sensor (substrate position detection means)
17 control part 21 1st control part 22 2nd control part 23 motor control part (driving means)
24 Position calculation unit (substrate position detection means, displacement calculation means)
25 Memory 221 Circumferential alignment unit 222 Limit condition detection unit 223 Memory WD Substrate V Rotation speed A Acceleration Vmax Maximum rotation speed Amax Maximum acceleration Va Limit speed Aa Limit acceleration D Displacement amount D2 Second displacement amount

Claims (7)

A rotation condition adjusting method for an alignment apparatus comprising a turntable, a drive means for rotating the turntable, and a substrate position detection means for detecting the position of a disk-shaped substrate placed on the turntable. ,
The substrate position detecting means includes
Two line sensors, which are arranged along the radial direction and at different angular positions at the peripheral edge of the substrate to detect the position of the substrate, respectively, and detect the edge positions thereof;
Displacement calculating means for obtaining a displacement amount caused by a displacement of the substrate with respect to the turntable with the rotation of the turntable based on the edge position detected by the two line sensors;
The two line sensors are arranged in a state in which the angular positions with respect to the center point of the turntable are shifted from each other by approximately 90 degrees, and at least one line sensor has X and Y axes defining the XY plane. It is arranged in a state shifted by a minute angle α from any axis,
A first step of rotating the turntable by the driving means in a state where the substrate is placed on the turntable;
Performing the second step of detecting the amount of displacement by the substrate position detecting means,
Based on the detected displacement amount, a limit speed or limit acceleration that is a rotation speed or acceleration that prevents the substrate from slipping is obtained.
A rotation condition adjusting method for an alignment apparatus characterized by the above. A third step of determining whether the detected displacement exceeds a threshold value;
A fourth step of recording the rotational speed or rotational acceleration of the turntable at or immediately before the displacement amount exceeds a threshold value as a limiting speed or a limiting acceleration;
When the amount of displacement does not exceed a threshold value, the fifth step of repeating the first to third steps by increasing the set value of the rotational speed or rotational acceleration of the turntable is executed. Item 2. A rotation condition adjusting method for an alignment apparatus according to Item 1. Based on the limit speed or the limit acceleration, the maximum rotation speed or maximum rotation acceleration of the turntable at the time of execution of alignment in the alignment device is set,
A rotation condition adjusting method for the alignment apparatus according to claim 1. A turntable,
Drive means for rotationally driving the turntable;
In order to detect the position of the disk-shaped substrate placed on the turntable, the edge positions of the disc-shaped substrate are respectively arranged along the radial direction and at different angular positions on the peripheral edge of the substrate. Substrate position detecting means including two line sensors, and a displacement calculating means for obtaining a displacement amount of the substrate based on the edge position detected by the two line sensors;
Control means for controlling the driving means and the substrate position detecting means,
The two line sensors are arranged in a state in which the angular positions with respect to the center point of the turntable are shifted from each other by approximately 90 degrees, and at least one line sensor has X and Y axes defining the XY plane. It is arranged in a state shifted by a minute angle α from any axis,
The control means includes
A first means for rotating the turntable by the driving means in a state where the substrate is placed on the turntable;
Second means for detecting the amount of displacement by the substrate position detecting means;
A third means for determining whether or not the amount of displacement caused by the displacement of the substrate with respect to the turntable as the turntable rotates exceeds a threshold value;
A fourth means for recording, as the limit speed or the limit acceleration, a rotation speed or rotation acceleration of the turntable at or immediately before the displacement amount exceeds a threshold value;
Fifth means for controlling to repeat the operations of the first to third means by increasing a set value of the rotational speed or rotational acceleration of the turntable when the displacement does not exceed a threshold value; Having
An alignment apparatus characterized by that. The substrate position detection means includes a spot sensor that detects an azimuth display reference provided on the substrate to detect a rotation angle position of the substrate,
The control means includes seventh means for aligning the substrate in the circumferential direction before starting the operations of the first means and the second means,
The seventh means includes
After the spot sensor detects the orientation display reference of the substrate placed on the turntable, the circumferential alignment is performed by rotating the substrate from the state by a predetermined rotation angle θa. Do,
The alignment apparatus according to claim 4 . The control means performs eighth processing for preliminarily removing the position of the azimuth display reference from the positions of the two line sensors before performing the circumferential alignment by the seventh means. Have
The eighth means includes
The edge position is detected by the two line sensors, the edge position is detected again by the two line sensors after the turntable is rotated by a small angle β,
The preliminary processing is performed by repeatedly performing the rotation of the minute angle β and the detection of the edge position until the difference between the detected edge positions is within an allowable range.
The alignment apparatus according to claim 5 . The substrate processing apparatus in which the alignment device is provided according to any one of claims 4 to 6.

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