JP2002076097A - Wafer transferring apparatus and method for wafer alignment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer transferring apparatus and a method for wafer alignment with a function for alignment by which a semiconductor wafer is aligned by using a simple mechanism and control at low cost, by saving space and with high efficiency. SOLUTION: The wafer transferring apparatus with the function for alignment comprises a wafer transferring means and a wafer rotating means. The wafer transferring means provides a wafer holding means 13 holding and transferring the wafer 7 and a means 14 for detecting the edge of the wafer 7. The wafer rotating means is provided in the region where the wafer transferring means can place the wafer 7, and holds and rotates the wafer 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for mapping, extracting, and performing in a transfer step of a semiconductor wafer.
It is involved in a series of wafer alignment work processes such as positioning, placing, etc., and in particular, loading a plurality of wafers stored at predetermined intervals in a container or cassette such as SMIF / POD or FOUP at a predetermined position or at a predetermined angle. TECHNICAL FIELD The present invention relates to a wafer transfer apparatus and a wafer alignment method used for performing a wafer transfer step requiring an alignment function for mounting.

[0002]

2. Description of the Related Art As a conventional wafer alignment method, a method disclosed in Japanese Patent No. 2856816 is generally known. Referring to the contents described in the publication, this alignment method includes a robot in which the robot arm can independently move in a radial direction, a rotating direction, and an elevating direction, and a wafer rotating in a wafer mounting area of the robot arm. A support table is provided, and an edge detector for detecting a position of the wafer rotated on the rotary support table is provided. Then, by the operation of the robot arm, the wafer is placed on the rotary support table and rotates on the edge detector. The edge position is detected by an electronic device that determines the amount of center movement to place the reference point on the wafer at a predetermined position to create alignment of the wafer on the rotating support. The robot is operated and the robot arm is operated to move the wafer on the rotating support until the reference point of the wafer is fixed at a predetermined position on the rotating support. To make the center of the wafer coincide with the rotation axis of the rotary support or to reduce the deviation between them,
It is described as possible by repeating the operation.

[0003] An alignment method using a CCD camera and an image processing function is also known. The outer peripheral shape of the wafer on the turntable is photographed by a CCD camera and output to an image processing unit. The image processing unit analyzes the obtained outer shape image and calculates a wafer shape, a deviation amount of the wafer center position, and a position (angle) of the orientation flat or the notch. The turntable is X-
If it is arranged on a stage that can move in the Y direction, it outputs the calculation result to a control unit that controls the stage, moves the turntable, and moves the wafer at a predetermined position and at a predetermined position. It is controlled so that it can be placed on If the rotary table is arranged on a stage that can move only in one direction (for example, the X direction), and is configured to move by a robot in the other direction (for example, the Y direction), The calculation results are output to both the control unit for controlling the table and the control unit for controlling the robot, and the movement is controlled so that the wafer can be placed at a predetermined position at a predetermined position and angle. . In the case of a mechanism in which the tip of the robot arm moves linearly, the operation is repeated until the wafer approaches a predetermined position.

Japanese Patent Application Laid-Open No. 12-31234 discloses a positioning (alignment) device comprising a CCD camera for detecting the position of an orientation flat and a rotating base that sucks and rotates a wafer. It is configured to be movable in the installation direction of the CCD camera, and the positioning device and the vertically movable wafer transfer robot are mounted next to each other on a common movable table. A substrate transfer apparatus is described that has a reduced footprint so that it can be simultaneously moved to and from a processing chamber.

On the other hand, an openable and closed container FOUP (FrontOpening Unified Pod) for 300 mm wafers
And the FOUP opener that opens and closes the container,
The latch mechanism of the FOUP door provided on the front surface of the container is opened, and the FOUP door stores the wafer in the FOUP.
The wafer is removed from the frame, moved horizontally, evacuated, and lowered to enable wafer transfer. In these openers, when the FOUP door is opened, the wafer may adhere to the wafer holding member provided on the door.
A wafer ejection sensor for interlock is provided near the outside of the OUP frame to detect the ejection state of the wafer. Then, when the wafer jump is detected, the opener operation is temporarily stopped, the wafer is returned to the normal position, and then the door opening operation is performed again.

However, the position of the wafer pop-out sensor is provided at a position about 20 mm away from the edge of the wafer at the wafer storage position (normal position) in the FOUP. This means that even if the wafer sticks to the FOUP door and moves with the door in the door opening operation, if the wafer is separated from the door before reaching the detection position of the pop-out sensor, the wafer storage state is It means that it is regarded as normal. That is, even if the detection result of the wafer pop-out sensor is normal, the wafer may actually be displaced in the in-out direction (X direction) by about 20 mm, and may be displaced in the Y direction orthogonal to the X direction. Is the difference between the width between the two wafer storage grooves facing each other in the Y direction and the diameter of the wafer, and the wafer is likely to be shifted from the center by about ± 2 mm.

The mapping means attached to the FOUP opener is disclosed in US Pat.
No. 2,214,483, and Japanese Patent Application Laid-Open No. 11-354609.

[0008] These proposals all point out that the mapping sensor is attached to a door holder for holding and opening the FOUP door.
The latch mechanism of the FOUP door is opened, the door is sucked and held, the door is retracted horizontally, and the sensor is operated so as to descend after checking that the wafer has not jumped out. And
It is proposed that the mapping sensor be configured to detect the stored state of the wafer in order from the top during the lowering operation of the door holder. As a detection sensor, a reflection sensor, a transmission sensor, an imaging unit, and the like have been proposed, but the common one of them is not for detecting a shift amount of the wafer in the X direction, but merely for detecting the presence or absence of the wafer. It only detects the storage state such as tilt and inclination.

If the wafer is to be taken out of the FOUP or the cassette by the transfer device while the wafer is displaced by about 20 mm from the normal position, the shape and size of the wafer holding means in which the amount of displacement is estimated in advance are necessary. Further, the alignment unit needs a detecting means for detecting a wide width which allows the shift amount, and further, in accordance with the shift amount, it is necessary to prevent the wafer from interfering with the constituent members constituting the transfer device. Instead, a large space is required to install the components in such a range.

Japanese Patent No. 2868645 and Japanese Patent Application Laid-Open No. 7-15538 disclose a transmission type sensor for mapping provided at the front end or rear end of a bifurcated wafer holding means.
No. 18, each of which is proposed in
No. 124289 also proposes.

[0011] In these, the transmission type sensor provided at the leading end or the rear end of the wafer holding hand of the robot is moved into the cassette by operating the robot, and the presence or absence of the wafer and the storage state are determined by the relative vertical movement of the cassette and the robot. , But not a wafer position shift.

Japanese Patent No. 2868645, Japanese Patent Application Laid-Open No.
The work to be detected by the transmission type sensor for mapping proposed in JP-A-153818 is a wafer of 200 mm or less housed in a cassette, and when this sensor is applied to a 200 mm SMIF opener using a SMIF box, the position of the sensor becomes normal. Any position (0
mm to several mm or more), and is usually provided at a position of about 2 mm. That is, a wafer with a small positional shift in front, rear, left and right can be an access target, and can be used as a wafer pop-out sensor.

[0013] The one proposed in Japanese Patent Application Laid-Open No. 2000-124289 is intended for a 300 mm FOUP. According to the contents of the publication, a transmission type sensor serving both as a mapping sensor and a seating sensor is provided at the tip of a bifurcated wear holder (hand), and the hand base side (rear end side) is in contact with the wafer edge. A contactable guide and a seating confirmation sensor are provided.

In this apparatus, when the wafer holder accesses the ejected wafer, first, the guide of the wafer holder collides with the wafer and pushes the wafer to a predetermined position. . Then, the transmission type wafer seating confirmation sensor provided at the rear end of the wear holding body confirms the seating of the wafer. That is, when the wafer is slightly displaced, the wafer end face always collides with the hand portion, and the wafer and the cassette groove accommodating the wafer are inevitably rubbed.

[0015] The contact and rubbing may cause not only generation of dust but also damage to the wafer. The degree of cleanliness required for recent FOUP openers and SMIF openers has changed from the conventional class 1 (one piece / cft for 0.1 μm particles) to class 0.1 (one piece / cft for 0.1 μm particles). . Rubbing and contact must be avoided as much as possible, even for a wafer that has jumped out of position, and damage to the wafer must be suppressed.

By the way, FOU for 300 mm wafer
In the case of P, the storage position (height) of the wafer is
Each value differs depending on P, and the variation is large. The cause of the variation is that the dimensions of the FOUP frame change with time. Also, the positioning method of the FOUP is
Three V-shaped long holes are also provided on the bottom surface of the P frame, and these are received by three pins each having an R-shaped tip of the V-shaped inclined surface.
The entire frame is supported by three pins and the FO
Because of the method of positioning the UP, wear of the pins and the V-shaped slope is inevitable, and the dimensions change each time the conveyance is repeated. Further, in addition to the used FOUP, a new FOUP is also supplied. 30 per semiconductor production line
It is said that more than 00 FOUPs will be loaded. Most of the conventional mapping information is information on the detection result of the presence or absence of a wafer or the storage state, and is information on the determination result of whether or not a wafer exists within a preset reference area (height). Was. In this case, if the reference area is narrowed, it is not possible to cope with the variation of each FOUP, and if the reference area is widened, there is a danger that the holding means comes into contact with the wafer when the holding means enters the cassette. I was out.

[0017]

As described above, for a wafer that may fly around 20 mm in the cassette,
If the conventional mapping method is used, Patent 2
The edge detection sensor used in the technique of 856816 requires a line sensor having an allowable width of at least 20 mm or more. Therefore, the amount of data to be handled becomes enormous, and high-speed arithmetic processing is required. Although it is possible to calculate the shift amount and angle of the wafer position, the arithmetic processing technology is also complicated and requires a high technology. The line sensor itself is very expensive, but the control unit for processing data at high speed is also quite expensive.

Further, Japanese Patent Application Laid-Open No.
The technology of JP-A-31234 and the like requires a control unit for analyzing and processing a huge amount of image information at high speed, and uses a mechanism for moving a rotary table to a CCD camera unit. It has become expensive.

Further, in the conventional handling method ignoring the protrusion of the wafer, there is no denying that the wafer may be damaged due to contact collision or that the wafer is contaminated by dust generated by rubbing. ,
The disadvantage that the space occupied by the device cannot be narrowed,
The height of the wafer changes each time the cassette is changed, and accessing the wafer based on the preset height has the disadvantage that the possibility of contact collision between the wafer holding means and the wafer stored in the cassette cannot be ruled out. there were.

As described above, the wafer alignment method in the conventional wafer transfer apparatus includes a detection means having a wafer rotation function and a wafer edge detection function for detecting a wafer shift amount and an angle, and a wafer transfer robot. In order to use expensive detection means, expensive analysis means for calculating and processing a huge amount of data obtained from the detection means is required. Also, moving means for moving the rotary table, which is a component of the detecting means, to the imaging unit is required. For this reason, both the control unit and the mechanical unit are complicated and expensive, and an increase in the cost of the entire apparatus has been inevitable. In addition, to achieve a narrow footprint,
Since the method of pushing the protruding wafer by the robot hand is employed, the problem of wafer damage due to dust generation and wafer damage due to contact collision cannot be eliminated.

The present invention solves the above-mentioned problems of the conventional wafer transfer apparatus and wafer alignment method, and corrects the wafer misalignment (center alignment) and adjusts the angle (phase, notch, orientation flat, etc.) of the wafer. The wafer state detection method and the wafer position correction method for performing the alignment are performed at a low cost and in a space-saving manner with a simple mechanism and control, thereby providing a highly efficient wafer alignment method, and in a container or a cassette. Even if the horizontally stored wafer is slightly displaced (about 20 mm), it can respond sufficiently without any special means and can access the wafer according to the storage height of the target wafer. It is an object to provide a transfer device and a wafer alignment method.

[0022]

SUMMARY OF THE INVENTION The present invention relates to a wafer transfer device and a wafer alignment method which solve the above-mentioned problems.
A wafer transfer device with an alignment function for aligning and transferring a semiconductor wafer to a processing device comprises a wafer transfer device and a wafer rotating device, wherein the wafer transfer device includes a wafer holding device for holding and transferring the wafer. ,
A wafer edge detecting unit for detecting an edge of the wafer, wherein the wafer rotating unit is provided in an area where the wafer transfer unit can place a wafer, and holds and rotates the wafer. And a wafer transfer device with an alignment function.

According to the first aspect of the present invention, as described above, the wafer transfer device includes a wafer transfer unit and a wafer rotation unit, and the wafer transfer unit includes:
It is provided with a wafer holding means and a wafer edge detecting means. Further, since the wafer edge detecting means is provided not in the opener but in the wafer transfer means, no space is required, and the footprint is not required. And a wafer transfer device having an alignment function with a narrow width.

According to the second aspect of the present invention, a plurality of wafers are horizontally stored at predetermined intervals in a container or a cassette. . As a result, the wafer transfer operation is streamlined, the wafer holding operation by the wafer holding unit is facilitated, the possibility that the wafer holding unit contacts the wafer and the wafer is damaged is reduced, and the wafer alignment operation is performed. The whole is streamlined.

Further, as described in claim 3, claim 1
Alternatively, according to the second aspect of the present invention, the wafer edge detecting means is composed of an optical transmission type sensor,
The transmission type sensor is provided at the base of the wafer holding portion of the wafer holding means, with its optical axis being substantially horizontal, and detects the edge of the wafer. As a result, when the wafer holding means accesses the wafer to take out the wafer, the transmission type sensor can detect the edge position of the wafer, and the center of the wafer located at a position separated by a radius of the wafer from this position. The existence line Y1 can be accurately detected. This can greatly contribute to simplifying, facilitating, and improving the efficiency of the subsequent wafer alignment work. Further, the transmission type sensor is not affected by the film or color of the wafer surface at all, as compared with the reflection type sensor, so that the edge of the wafer can be detected with high accuracy.

The invention described in claim 4 is:
A wafer alignment method for aligning the wafer using the wafer transfer device with an alignment function according to any one of claims 1 to 3, wherein at least the next step, that is, moving the wafer transfer means is performed. A first wafer edge detecting step of detecting an edge of the wafer by the wafer edge detecting means; and a first wafer edge position information obtained in the first wafer edge detecting step. A first mounting step of correcting and controlling the moving distance of the wafer holding means and mounting the wafer on the wafer rotating means, a first rotating step of rotating the wafer rotating means by a predetermined angle, and the wafer transfer means A second wafer edge detecting step of detecting the edge of the wafer placed on the wafer rotating means by the wafer edge detecting means, and the second wafer edge The movement distance of the wafer holding means is corrected and controlled based on the second wafer edge position information obtained in the unloading step, and the wafer is moved to a predetermined position of the wafer rotating means and re-mounted, or A second mounting / transfer step of transferring the wafer to a processing chamber as it is.

The invention described in claim 4 is configured as described above, so that the wafer transfer means is moved,
First wafer edge position information is obtained by a first wafer edge detection step of detecting the edge of the wafer by the wafer edge detection means, and a first center existence line Y1 of the wafer is obtained based on the first wafer edge position information. By correcting and controlling the moving distance of the wafer holding means based on the position information of the first center existence line Y1, the wafer can be used as the wafer rotating means, and the first center existence line Y1 of the wafer can be obtained. The wafer can be mounted so as to be orthogonal to the rotation axis of the wafer rotating means (first mounting step). Next, the wafer rotating means is rotated by a predetermined angle (for example, 90 °) (first rotation step), and the wafer transfer means is moved toward the wafer whose rotation angle position on the wafer rotating means is different by a predetermined amount. The second wafer edge position information is obtained by a second wafer edge detection step of detecting the edge of the wafer placed on the wafer rotating means by the wafer edge detection means, and the second wafer edge position information is obtained. The position of the second center line Y2 of the wafer at a position rotated by a predetermined angle from the position of the first center line Y1 of the wafer can be calculated based on the position information of the second center line Y2. By correcting and controlling the moving distance of the wafer holding means based on the data, the wafer is moved to a predetermined position of the wafer rotating means,
The wafer can be moved and re-mounted or transferred directly to the processing chamber such that the second center line Y2 of the wafer is orthogonal to the rotation axis of the wafer rotating means (the second mounting / transfer step). ).

By going through these steps,
The center of the wafer and the rotation axis of the wafer rotating means are almost completely coincident with each other, and the deviation of the wafer from the position to be mounted on the wafer rotating means is eliminated. In this way, the centering operation of the wafer can be easily realized by the simple operation principle, and the alignment of the wafer can be surely executed. During this time, the wafer edge detecting means detects the wafer edge twice when the wafer holding means accesses the wafer, and controls the movement of the wafer holding means twice based on the obtained wafer edge position information. , And only a predetermined angular rotation amount control of the wafer rotating means is performed during the first and second movement amount correction control of each wafer holding means, and the structure of a mechanism and a control part for their detection and control. Is simplified, easy and inexpensive, and eliminates the need for complicated and expensive data processing-related line sensors and imaging means that have been indispensable for conventional wafer alignment. The cost of the entire wafer transfer device used can be reduced. Reloading of the wafer on the wafer rotating means in the second mounting / transfer step is not necessarily performed, and the wafer may be directly transferred to the processing chamber.

According to a fifth aspect of the present invention, the first mounting step includes the step of detecting the center line Y1 of the wafer detected in the first wafer edge detecting step. Is a step of placing the wafer on the wafer rotating means so as to be perpendicular to the rotation axis of the wafer rotating means. In the first rotating step, the wafer edge on the center existing line Y1 of the wafer is This is a step of rotating the wafer rotating means until the angle becomes such as to be detected by the edge detecting means. As a result, the rotation angle of the wafer rotation means in the first rotation step is set to 90 °, so that the movement direction of the wafer holding means in the second mounting / transfer step is the movement direction of the wafer holding means in the first mounting step. The operation of reloading the wafer on the wafer rotating means in the second mounting / transfer step is the simplest. This further simplifies and reduces the configuration of the mechanism and control unit for controlling the amount of movement of the wafer holding unit based on the wafer edge position information, and further reduces the cost of the entire wafer transfer device. Can be.

Further, as described in claim 6, claim 4
In the first placing step and the second placing / transferring step, the moving distance of the wafer holding means is determined based on the first wafer edge position information and the second wafer edge position information. In performing the correction control, the position at which the wafer holding means places the wafer on the wafer rotating means is corrected and controlled. As a result, the position where the wafer holding means picks up the wafer can always be a fixed position irrespective of the amount of displacement of the wafer, and a position where the edge of the wafer is to be detected is set in advance, and this position and the actual position are set. The first detected in
The difference between the wafer edge position and the second wafer edge position is determined until the wafer holding unit picks up the wafer, moves the wafer, and mounts the wafer on the wafer rotating unit (re-mounts in the second mounting / transfer process). As the correction amount for correcting the movement amount of the wafer, the position at which the wafer is finally mounted on the wafer rotating means may be corrected and controlled. Thus, the wafer alignment operation can be easily performed.

According to the seventh aspect of the present invention, in the first placing step and the second placing / transferring step, the first wafer edge position information and the second (2) In order to correct and control the moving distance of the wafer holding means based on the wafer edge position information, the position at which the wafer holding means picks up the wafer is corrected and controlled. As a result, the wafer holding means is corrected and controlled so as to always stop at a position moved by a fixed distance from the first and second wafer edge detection points, so that the wafer can be picked up at this position. The wafer can be directly placed on the wafer rotating means at the set position. Thus, the wafer alignment operation can be easily performed.

Further, according to the present invention, the position at which the wafer holding means picks up the wafer stops the movement of the wafer holding means at the time of detecting the wafer edge. Position. As a result,
The wafer holding means is adapted to stop at that position at the time of detecting the first and second wafer edges, to pick up the wafer at this position, and to rotate the wafer at a preset position. Can be placed as is. Thereby, the correction control of the moving distance of the wafer holding means is made unnecessary (the correction amount is zero) at its limit, so that the wafer alignment operation can be more easily executed.

Further, the invention described in claim 9 is a wafer alignment method for aligning the wafer by using the wafer transfer device with alignment function according to claim 1 or 2. At least in the following steps, that is, a first wafer edge detection step in which the wafer transfer means is moved and the wafer edge detection means detects an edge of the wafer, and a first wafer edge detection step. A first mounting step of mounting and controlling the movement distance of the wafer holding means based on the obtained first wafer edge position information to mount the wafer on the wafer rotation means; A first rotation step of rotating the wafer by an angle, and a step of moving the wafer transfer means so that the wafer edge detection means detects an edge of the wafer placed on the wafer rotation means. And wafer edge detection step, the second
The moving distance of the wafer holding means is corrected and controlled based on the second wafer edge position information obtained in the wafer edge detecting step, and the wafer is moved to a predetermined position of the wafer rotating means and remounted. A second mounting step, wherein a notch or orientation flat of the wafer re-mounted on the wafer rotating means is detected by the wafer edge detecting means, and the wafer is positioned at a predetermined position of the wafer rotating means. A wafer alignment method characterized by comprising two rotation steps.

According to the ninth aspect of the present invention, since it is configured as described above, by moving the wafer transfer means,
First wafer edge position information is obtained by a first wafer edge detection step of detecting the edge of the wafer by the wafer edge detection means, and a first center existence line Y1 of the wafer is obtained based on the first wafer edge position information. By correcting and controlling the moving distance of the wafer holding means based on the position information of the first center existence line Y1, the wafer can be used as the wafer rotating means, and the first center existence line Y1 of the wafer can be obtained. The wafer can be mounted so as to be orthogonal to the rotation axis of the wafer rotating means (first mounting step). Next, the wafer rotating means is rotated by a predetermined angle (for example, 90 °) (first rotation step), and the wafer transfer means is moved toward the wafer on the wafer rotating means having a different rotation angle position by a predetermined amount. The second wafer edge position information is obtained by a second wafer edge detection step of detecting the edge of the wafer placed on the wafer rotating means by the wafer edge detection means, and the second wafer edge position information is added to the second wafer edge position information. The position of the second center existence line Y2 of the wafer at a position rotated by a predetermined angle from the position of the first center existence line Y1 of the wafer can be calculated based on the position information of the second center existence line Y2. By correcting and controlling the moving distance of the wafer holding means based on the data, the wafer is moved to a predetermined position of the wafer rotating means,
The wafer can be moved and mounted again so that the second center existence line Y2 of the wafer is orthogonal to the rotation axis of the wafer rotating means (second mounting step). Further, the notch or the orientation flat of the wafer re-mounted on the wafer rotating means is detected by the wafer edge detecting means, and this can be positioned at a predetermined position of the wafer rotating means (second).
Rotation process).

By going through these steps,
The center of the wafer and the rotation axis of the wafer rotating means are almost completely coincident with each other, and the deviation of the wafer from the position to be mounted on the wafer rotating means is eliminated. Further, the notch or orientation flat of the wafer is positioned at a predetermined position of the wafer rotating means, and the phases are adjusted. In this way, the centering operation of the wafer can be easily realized by the simple operation principle, and the alignment of the wafer can be reliably performed together with the centering and the phase alignment of the wafer. During this time, the wafer edge detecting means detects the wafer edge twice when the wafer holding means accesses the wafer, and controls the movement of the wafer holding means twice based on the obtained wafer edge position information. A predetermined angle rotation amount control of the first wafer rotation means during the first and second movement amount correction control of each wafer holding means, and a second rotation of the wafer rotation means for positioning the notch or the orientation flat of the wafer; Only the amount of rotation is controlled, and the structure of the mechanism and control unit for their detection and control is simplified, easy and inexpensive, and complicated and expensive, which has been indispensable for conventional wafer alignment. Since a line sensor and an imaging means with complicated data processing are not required, a wafer alignment method including notch or orientation flat phase adjustment is required. It is possible to reduce the cost of the entire wafer transfer device used to.

In addition, as described in claim 10, claim 9
According to the invention described in (1), the wafer edge detecting means is constituted by an optical distance-limited reflection type sensor. Here, this distance-limited reflective sensor is:
Of course, it can be used to detect the wafer edge,
Since this sensor is also suitable for detecting a notch or orientation flat of a wafer, using this sensor, the first and second wafer edge detection steps for centering the wafer and the second phase for detecting the phase of the notch or orientation flat of the wafer can be performed. All of these detections can be performed in the two-rotation process, and the configuration of the wafer edge detection means used for performing the wafer alignment method including notch or orientation flat phase alignment can be greatly simplified.
The reflection sensor can also be used as a wafer presence confirmation sensor for confirming that the wafer is present on the wafer holding means when the wafer holding means holds the wafer. Of course, the wafer presence confirmation sensor may be provided separately.

[0037] In addition, as described in claim 11, claim 9
Alternatively, by configuring the invention according to claim 10,
The wafer rotating means is driven by a numerically controllable servomotor. As a result, when the notch or orientation flat of the wafer is phase-aligned, if the wafer edge detection means outputs OFF at a position where these are detected and ON at a position where they are not detected, the output becomes O.
Read the position of the encoder provided on the servomotor when changing from N to OFF or from OFF to ON,
By considering the median value between the value near one end of both ends of the notch or orientation flat and the value near the other end as the median value of the notch or orientation flat,
These notches or orientation flats can be easily phase-matched.

Further, according to the twelfth aspect of the present invention, the wafer edge detecting means comprises an optical transmission type sensor, and the transmission type sensor includes an optical transmission type sensor. The axis is substantially vertical, and is provided at the base of the wafer holding portion of the wafer holding means so as to detect the edge of the wafer. Here, since the transmission type sensor arranged in this way is suitable not only for detecting the edge of the wafer but also for detecting the notch or the orientation flat of the wafer, the use of the transmission type sensor enables the center of the wafer to be detected. First and second wafer edge detection processes for alignment, and second second for wafer notch or orientation flat alignment
All of these detections in the rotation step can be performed, and the configuration of the wafer edge detection means used for performing the wafer alignment method including notch or orientation flat alignment can be greatly simplified. In addition, the transmissive sensor is not affected by the film or color on the wafer surface at all, as compared with the reflective sensor, so that highly accurate alignment can be realized. When higher accuracy is required, a transmission type line sensor or the like can be used.

Further, as described in claim 13, claim 9
According to the invention described in (1), the wafer edge detection means comprises an optical transmission sensor, and the transmission sensor has an optical axis substantially horizontal, and It is provided at the tip and detects the edge of the wafer. As a result, the transmission-type sensor can detect the edge of the wafer, and thus, the first and second wafer edge detection steps for centering the wafer can be performed. In this case, the detection accuracy of the wafer edge can be kept high. In addition, the transmission type sensor has its optical axis made substantially horizontal and is provided at the tip of the wafer holding part of the wafer holding means. Compared with the case where the wafer is provided at the base, even if the upper wafer of the wafer to be edge-detected pops out, the wafer to be edge-detected can be lifted and taken out without retreating the wafer holding means, The operation of taking out the wafer can be simplified.

[0040] Also, as described in claim 14, claim 1
According to the third aspect of the invention, the transmission-type sensor is configured to detect at least the edge position of the wafer and the storage height position of the wafer. As a result, even if there is a variation in the storage height position of the wafer in the FOUP or the cassette in which dimensional deviation, distortion, torsion, etc. due to aging have occurred, before the wafer holding means enters the gap between the upper and lower wafers. Further, since the storage height position of the wafer can be accurately grasped, the wafer holding means can access the wafer to be detected at an appropriate height position corresponding to the storage height position of the wafer. Note that such a variation in the storage height position of the wafer may also occur due to warpage or bending of the wafer itself. Further, even if the wafer is slightly protruded, the edge position of the wafer can be grasped with high accuracy, so that the wafer holding means can access the wafer to be detected at an appropriate position corresponding to the edge position of the wafer. Can be stopped. Thus, when the wafer holding unit accesses the wafer to be detected, the wafer and the upper and lower wafers adjacent to the wafer are not damaged.

Further, by constituting the invention according to claim 13 or claim 14 as described in claim 15, the transmission type sensor has a mapping function for mapping a stored state of a wafer. . As a result, the transmission-type sensor can detect not only the edge position of the wafer, the storage height position, the gap between the upper and lower wafers, but also the state of the presence or absence of the wafer, and comprehensively determine the storage state of the wafer. You will be able to grasp it. This allows
A wafer alignment method capable of performing not only wafer alignment but also wafer mapping can be realized.

In addition, as described in claim 16, claim 9
According to the invention described in (1), the wafer edge detecting means comprises an optical transmission sensor, and the transmission sensor has an optical axis substantially horizontal, and A wafer presence detection unit is provided at the tip end, and is configured to detect an edge of the wafer, and further detects wafer presence, and the wafer presence detection unit includes:
An optical reflection sensor is provided at the base of the wafer holding section of the wafer holding means, and detects the vicinity of the edge of the wafer. As a result, the transmissive sensor can be used to detect the edge of the wafer and the reflective sensor can be used to detect the presence of the wafer and the notch or orientation flat of the wafer, thereby providing the centering of the wafer. First and second wafer edge detection steps,
These detections can be performed in the second rotation step for confirming the presence of the wafer and for aligning the notch or orientation flat of the wafer. In this case, since the transmission sensor detects the wafer edge, the detection accuracy of the wafer edge can be maintained at a high level. In addition, the transmission type sensor has its optical axis made substantially horizontal and is provided at the tip of the wafer holding part of the wafer holding means. Compared with the case where the wafer is provided at the base, even if the upper wafer of the wafer to be edge-detected pops out, the wafer to be edge-detected can be lifted and taken out without retreating the wafer holding means, The operation of taking out the wafer can be simplified.

According to a seventeenth aspect of the present invention, there is provided a wafer alignment method for aligning the wafer using the wafer transfer device with the alignment function according to the first or second aspect, At least the next step, ie, lowering the wafer holding means near the edge of the wafer, mapping the wafer by the wafer edge detection means, and detecting the height position of the wafer In the height direction of the wafer detected in the wafer height direction position detection step, and horizontally moving the wafer holding means in the forward direction at the wafer height direction position detected in the wafer height direction position detection step. A wafer edge detecting step of detecting an edge of the wafer, the wafer holding means is lowered to avoid interference with the wafer, And moved horizontally back forward direction,
A wafer holding target position stopping step of stopping at a lower wafer holding target position of the wafer based on the wafer edge position information obtained in the wafer edge detecting step, and raising the wafer holding unit to hold the wafer. Means for holding the wafer and then retreating the wafer so as to transfer the wafer to the wafer rotating means or the processing chamber.

According to the seventeenth aspect of the present invention, as described above, the wafer holding means can execute the operations necessary for wafer alignment and wafer transfer in a short time through the shortest distance. Can be.

Further, by configuring the invention according to claim 17 as described in claim 18, the wafer edge detecting means comprises an optical transmission type sensor, and the transmission type sensor includes an optical transmission type sensor. The axis is made substantially horizontal, and is provided at the tip of the wafer holding portion of the wafer holding means to detect the edge of the wafer and to map the wafer. As a result, the detection of the edge of the wafer and the mapping of the wafer can be performed with high accuracy by the transmission type sensor and efficiently with one operation by lowering the wafer holding means.

Further, the invention described in claim 19 is the wafer transfer device with the alignment function according to claim 1 or 2, wherein the wafer transfer means moves the wafer holding means substantially horizontally. A horizontal linear movement mechanism for moving the horizontal linear movement mechanism in a substantially linear manner, a lifting mechanism for raising and lowering the horizontal linear movement mechanism, and a turning mechanism for rotating the horizontal linear movement mechanism. The horizontal linear movement mechanism, the lifting mechanism and Each of the turning mechanisms is driven by a motor that can be numerically controlled, and the wafer rotating means has a suction means for holding the wafer, and is provided on a movement locus of the wafer holding means by the horizontal linear movement mechanism. The wafer transfer means and the wafer rotating means are arranged within the radius of rotation of the wafer holding means. A wafer transfer device with an alignment function, wherein the wafer transfer device has a front end provided on a carrier and provided in a controlled space for transferring the wafer between an opener and a processing chamber. Device.

According to the nineteenth aspect of the present invention, as described above, the wafer rotating means is positioned within the rotation radius of the wafer holding means on the movement locus of the wafer holding means by the horizontal linear movement mechanism. Thus, the wafer transfer device with the alignment function can be arranged in a smaller area. In addition, the wafer transfer means and the wafer rotation means
It is arranged on a carrier moving in orbit and can transfer wafers while performing wafer alignment between one or more SMIF openers or FOUP openers and the processing chamber, so that the front of a narrower footprint can be obtained. End can be realized.

[0048]

Next, an embodiment (Embodiment 1) of the invention described in claims 1 to 6 and 19 of the present application shown in FIGS. 1 to 5 will be described. FIG. 1 is a diagram showing a layout of the entire wafer processing equipment in which the wafer transfer device according to the first embodiment is used, FIG. 2 is a plan view showing a positional shift state of the wafer stored in the FOUP, and FIG. FIG. 4 is a side sectional view, FIG. 4 is a plan view illustrating a state in which a wafer holding unit enters the FOUP, and an optical axis of a transmission sensor provided on the wafer holding unit detects a wafer edge, and FIG. 4 is a partial side view of FIG.

As shown in FIG. 1, a wafer processing facility 1 in which a wafer transfer device 10 according to the first embodiment is used.
Is a wafer processing apparatus 3 in which a front end 2 is elongated in the center and a plurality of wafer processing chambers (not shown) are arranged on one side of the front end 2 and a plurality of FOUP openers are provided on the other side. Wafer supply unit 4 in which 5 are juxtaposed
, Respectively. Although not shown in detail, the FOUP opener 5 has an F
OUP6 (see FIGS. 2 to 4) is mounted, and FOU
When P opener 5 opens the door of FOUP 6, FOU
A plurality of semiconductor wafers 7 horizontally stored at predetermined intervals in P6 are taken out one by one by a wafer holding means (robot arm) 13, which will be described later, of the wafer transfer device 10,
The wafer is aligned in a predetermined posture (position, angle) and transferred to a wafer processing chamber where a predetermined process is scheduled. Therefore, the wafer transfer device 10 is configured as a wafer transfer device with a wafer alignment function.

The wafer transfer device 10 comprises a wafer transfer means 11 composed of a robot and a wafer rotation means (rotary table) 12.
Consists of The wafer transfer means 11 includes a wafer holding means 13 for holding and transferring the wafer 7 and a wafer edge detection means 14 comprising an optical transmission type sensor for detecting the edge of the wafer 7 (FIG. FIG. 5). The wafer holding means 13 includes a first arm 13a, a second arm 13b, and a hand portion 13c corresponding to a third arm. The hand unit 13c forms a wafer holding unit that actually holds the wafer 7. As shown in FIGS. 4 and 5, the wafer edge detecting means 14 has an optical axis 14a substantially horizontal, and has a bottom portion of a front U-shaped open portion of the hand portion 13c (hereinafter, this portion). Is referred to as “the base of the wafer holding unit (hand unit 13 c) of the wafer holding unit 13”) to detect the edge of the wafer 7.

Although not shown in detail, the wafer transfer means 11 includes a horizontal linear moving mechanism for moving the wafer holding means 13 substantially horizontally and substantially linearly in order to give the wafer holding means 13 a three-dimensional movement. A lifting mechanism for raising and lowering the horizontal linear moving mechanism, and a turning mechanism for rotating the horizontal linear moving mechanism. The horizontal linear moving mechanism, the lifting mechanism and the turning mechanism are motors each capable of numerical control. Being driven. Hand part 13c of wafer holding means 13
Moves linearly in the radial direction through the rotation of the first arm 13a and the second arm 13b by the action of the horizontal linear movement mechanism. Then, facing the open FOUP 6,
The wafer 7 moves forward and backward, takes out the wafer 7 in the FOUP 6, and returns the processed wafer 7 to the original position.

The wafer rotating means 12 is provided in an area A of the wafer transfer means 11 where the wafer can be placed, and has suction means (not shown) for holding the wafer 7. It is configured to rotate while being sucked and held on the mounting surface, where the final alignment work of the wafer 7 is performed. The area A is defined as an area within the radius of rotation of the wafer holding means 13 on the movement trajectory of the wafer holding means 13 by the horizontal linear movement mechanism described above.

The wafer transfer means 11 and the wafer rotating means 12 constituting the wafer transfer apparatus 10 constitute the front end 2, and are not shown in detail but on a numerically controllable carrier moving on a track 15. FO
It travels integrally between the UP opener 5 and the processing chamber. The front end 2 transfers the wafer 7
A controlled space is maintained.

Next, a wafer alignment method for aligning the wafer 7 by centering the wafer 7 (eliminating the center shift) using the wafer transfer device 10 having the alignment function having the above-described configuration. The reason why such a wafer alignment method can be adopted is as follows. For example, in a furnace (furnace) heat treatment process for a 300 mm sheet type, FOUP
The accuracy of transferring the wafer 7 stored in the (or cassette) 6 to the furnace is not limited as long as the mounting accuracy at the center of the wafer is about ± 2 mm, regardless of the position and angle of the notch. The wafer 7 taken out of the FOUP 6 is stored again in the FOUP 6 after the heat treatment. The accuracy at that time is
It is sufficient if it is ± 1 mm or less. Therefore, FOUP6
The wafer holding means 13 for transferring the internal storage wafer 7 includes:
It enters the FOUP 6 while maintaining an appropriate distance from the wafer 7, and detects the edge of the wafer 7 during the approach operation.
Detect at 14. Note that the wafer edge detecting means 14 is
It is arranged to detect the edge position most protruding from P6. The displacement of the storage wafer 7 in the entry direction (X direction) of the wafer holding means 13 is within 20 mm, and the displacement in the Y direction orthogonal to the entry direction is about ± 2 mm, and ± 2 mm.
Since the error when the influence of the positional displacement in the front and rear Y directions is replaced in the X direction is about 0.01 mm, it is approximately on a straight line 150 mm forward from the position where the edge in the X direction is detected (center existence line Y1). It can be seen that the center of the wafer exists within a width of about ± 2 mm. As a result, even if the following wafer alignment method is employed, there is no particular problem in the mounting accuracy of the wafer center position.

This wafer alignment method includes at least the following steps. That is, first, as shown in FIGS. 4 and 5, the wafer holding means 13 of the wafer transfer means 11 is moved to access the wafer 7 at a predetermined height position. Then, the hand portion 13c is made to enter the lower portion of the wafer 7, and the edge of the wafer 7 is detected by the wafer edge detecting means 14 comprising a transmission type sensor provided at the base thereof (first wafer edge detecting step). . By this step, the center existence line Y1 where the center of the wafer 7 exists is located at a position separated by the radius of the wafer 7 from the position where the optical axis 14a of the transmission sensor 14 detects the edge of the wafer 7. I understand.

Next, the wafer edge position detected in the first wafer edge detection step is stored as position information on the robot side, and the movement of the wafer holding means 13 is performed based on the first wafer edge position information. The distance is corrected and controlled so that the wafer 7 is finally mounted on the wafer rotating means 12 so that the first center line Y1 of the wafer 7 is orthogonal to the rotation axis of the wafer rotating means 12. (First mounting step). Here, "perpendicular to the rotation axis" means through the rotation axis,
It means that it is orthogonal to this. In practice, a position where a wafer edge is to be detected is set in advance on the wafer holding means 13, and the difference between this position and the actually detected first wafer edge position is determined by the wafer holding means 13. Picks up the wafer 7, moves it, and uses it as a correction amount for correcting the movement amount until it is mounted on the wafer rotating means 12.
Is controlled so that the position at which the wafer is placed on the wafer rotating means 12 does not deviate from the center. In this way, the position where the wafer holding means 13 picks up the wafer 7 is
Irrespective of the amount of displacement of the wafer 7, it can be always at a fixed position, and the wafer alignment operation can be easily performed.

Next, the wafer rotating means 12 is turned at a predetermined angle (9
0 °) (first rotation step). This is the wafer 7
And rotating the wafer rotating means 12 until the wafer edge on the line of the center existence line Y1 is detected by the wafer edge detection means 14. Preparations are made for the wafer edge detection means 14 to detect the edge. Then, the wafer transfer means 13 is moved, and the new wafer edge of the wafer 7 placed on the wafer rotating means 12 is moved by the wafer edge detection means 14 in the same manner as in the first wafer edge detection step. Detect (second
Wafer edge detection step). By this process, transmission type sensor
From the position where the 14 optical axes 14a detect the wafer edge, the wafer 7
It can be seen that there is a center existence line Y2 where the center of the wafer 7 exists at a position separated by a distance of a radius of.

Finally, the wafer edge position detected in the second wafer edge detection step is stored as position information on the robot side, and the movement of the wafer holding means 13 is performed based on the second wafer edge position information. Correcting and controlling the distance, the wafer 7 is finally moved to a predetermined position of the wafer rotating means 12 so that the second center existence line Y2 of the wafer 7 is orthogonal to the rotation axis of the wafer rotating means 12. Then, it is mounted again (second mounting step). Actually, a position where the wafer edge is to be detected is set in advance on the wafer holding means 13, and the difference between this position and the actually detected second wafer edge position is determined by the wafer holding means 13. Is used as a correction amount for correcting the movement amount until the wafer 7 is picked up, moved, and re-mounted on the wafer rotating means 12, and finally the wafer 7 is moved to the wafer rotating means 12 and re-mounted. Is corrected and controlled so that the center shift does not occur. In this way, the position where the wafer holding means 13 picks up the wafer 7 is
Irrespective of the amount of displacement of the wafer 7, it can be always at a fixed position, and the wafer alignment operation can be easily performed. The wafer rotating means 12 for the wafer 7 described above.
The re-mounting of the wafer 7 need not always be performed, and the wafer 7 may be transferred to the processing chamber as it is. The reason is that the movement of the wafer holding means 13 based on the second wafer edge position information is controlled to be corrected by the wafer holding means 13.
This is because the wafer 7 can be correctly held at the same position.

The wafer alignment method according to the first embodiment has the following effects by performing the above steps. First, the center of the wafer and the rotation axis of the wafer rotating means 12 are almost completely matched, and the deviation amount of the wafer 7 from the position to be mounted on the wafer rotating means 12 is eliminated. In this way, the centering operation of the wafer 7 can be easily realized based on the simple operation principle, and the alignment of the wafer 7 can be surely executed. During this time, the wafer holding means 13
Detection of the wafer edge twice by the wafer edge detection means 14 at the time of the access operation to the wafer 7, and the wafer holding means based on the obtained wafer edge position information twice.
The movement amount correction control of the wafer rotation means 12 and the rotation angle control of the wafer rotation means 12 during the first and second movement amount correction control of each wafer holding means 13 are only performed. -The structure of the control mechanism and control unit is simplified, easy and inexpensive, and the line sensors and imaging means with complicated and expensive data processing that have been indispensable for conventional wafer alignment Since it becomes unnecessary, it is possible to reduce the cost of the entire wafer transfer apparatus used for performing the wafer alignment method.

Further, since the rotation angle of the wafer rotation means 12 in the first rotation step is 90 °, the second mounting
The moving direction of the wafer holding means 13 in the transfer step is the first direction.
The moving direction of the wafer holding means 13 in the mounting step may be the same as that in the second mounting / transferring step.
The operation of reloading the wafer on the wafer rotating means 12 is most simplified. This further simplifies and reduces the configuration of the mechanism and the control unit for controlling the movement amount of the wafer holding unit 13 based on the wafer edge position information, thereby reducing the cost and further reducing the overall cost of the wafer transfer device 10. Can be planned.

Further, the position where the wafer holding means 13 picks up the wafer 7 can always be a fixed position irrespective of the amount of displacement of the wafer 7, and the position where the wafer edge is to be detected is set in advance. The wafer holding means 13 picks up the wafer, moves it, and places it on the wafer rotation means 12 (second position). The difference between this position and the actually detected first wafer edge position and second wafer edge position. In the mounting / transfer process, the amount of movement until re-mounting is used as a correction amount for correcting
The position where the wafer 7 is finally placed on the wafer rotating means 12 may be properly corrected and controlled so that there is no center shift. Thus, the wafer alignment operation can be easily performed.

Further, since the wafer transfer device 10 used in the wafer processing equipment 1 according to the first embodiment is configured as described above, the following effects can be obtained. The wafer rotation unit 12 is disposed within the rotation radius of the wafer holding unit 13 on the movement trajectory of the wafer holding unit 13 by the horizontal linear movement mechanism, and the wafer transfer device 10 with the alignment function can be arranged in a smaller area. Will be possible. Further, the wafer transfer means 11 and the wafer rotation means 12 are arranged on a carrier moving on a track, and execute wafer alignment between one or more SMIF openers 5 or FOUP openers 5 and the processing chamber. Wafer 7
Therefore, the front end 2 having a smaller footprint can be realized.

Next, an embodiment (Embodiment 2) of the invention described in claim 7 of the present application will be described. Embodiment 2
In the wafer alignment method using the wafer transfer device 10 with an alignment function in the above, in the first mounting step and the second mounting / transfer step, based on the first wafer edge position information and the second wafer edge position information, In order to correct and control the moving distance of the wafer holding means 13, the position where the wafer holding means 13 picks up the wafer 7 is controlled to be corrected. As a result, the wafer holding means 13 is corrected and controlled so as to always stop at a position moved a fixed distance from the first and second wafer edge detection points, so that the wafer 7 can be picked up at this position. Then, the wafer 7 is moved to move the wafer 7 at a preset position.
It can be placed correctly on 12 without any center shift. Thus, similarly to the first embodiment, the wafer alignment operation can be easily performed. In other respects, there is no difference from the wafer alignment method in the first embodiment, and a detailed description will be omitted.

Next, an embodiment (Embodiment 3) of the invention described in claim 8 of the present application will be described. Embodiment 3
In the wafer alignment method using the wafer transfer device 10 with the alignment function in the above, the wafer holding means
The position where the pick-up 13 picks up the wafer 7 is a position where the movement of the wafer holding means 13 is stopped at the time of detecting the wafer edge.
As a result, the wafer holding means 13 is caused to stop at that position at the time of detecting the first and second wafer edges, so that the wafer 7 can be picked up at this position, and at a preset position. Wafer rotating means
It can be placed correctly on 12 without any center shift. As a result, the correction control of the moving distance of the wafer holding means 13 is made unnecessary (the correction amount is zero) at its limit, so that the wafer alignment work is further performed as compared with the wafer alignment method in the first and second embodiments. Can be easily implemented. In other respects, there is no difference from the wafer alignment method in the first and second embodiments, and a detailed description thereof will be omitted.

Needless to say, the wafer alignment can be realized by appropriately combining the moving distance correcting methods of the three wafer holding means 13 in the first to third embodiments described above.

Next, an embodiment (Embodiment 4) of the invention described in claims 9 to 11 of the present application shown in FIGS. 6 to 9 will be described. FIG. 6 shows FOUP6
The wafer holding means 13 of the wafer transfer device 10 used for performing the wafer alignment method according to the fourth embodiment enters thereinto, and the light of the optical distance-limited reflection type sensor 16 provided on the wafer holding means 13 is provided. FIG. 7 is a plan view illustrating a state where the shaft 16a has detected the wafer edge, FIG. 7 is a side sectional view of FIG.
9 is a perspective view illustrating a state in which the optical axis 16a of the reflective sensor 16 detects the notch 17, and FIG. 9 is a perspective view illustrating a state in which the optical axis 16a of the reflective sensor 16 detects the orientation flat 18. is there.

In order to position the notch 17 or the orientation flat 18 of the wafer 7, first, the center position of the wafer 7 substantially coincides with the rotation axis of the wafer rotation means 12. As described in the first to third embodiments, in the first wafer edge detecting step and the first placing step, the wafer center existing line Y1 is placed so as to pass through the axis of the wafer rotating means 12. Next, in a first rotation step, the wafer rotation means
Step 12 rotates the wafer 7 by 90 degrees. Next, the second
In the wafer edge detecting step and the second placing step, the wafer 7 is placed on the wafer rotating means 12 again. Through these steps,
The center of the wafer 7 can be substantially coincident with the rotation axis of the wafer rotating means 12.

In the fourth embodiment, in addition to the above-described wafer alignment (centering) in the first to third embodiments, the notch 17 of the wafer 7 or the phase adjustment of the orientation flat 18 (second rotation step) ) Is performed. That is, the notch 17 or the orientation flat 18 of the wafer 7 re-mounted on the wafer rotating means 12 by the second mounting / transfer process in the first to third embodiments is detected by the wafer edge detecting means 14 and is determined by a predetermined value. The rotation of the wafer rotating means 12 is controlled so as to be at the angle shown in FIG. Thus, the wafer 7 is positioned at a predetermined position of the wafer rotating means 12. Through this additional step, both centering and phase matching of the wafer 7 are completed. The wafer 7 positioned and phase-matched in this manner is picked up by the wafer holding means 13 of the wafer transfer device 10 and transferred to a predetermined position.

First, a method of aligning a notched wafer according to the fourth embodiment will be described. As shown in FIGS. 6 to 8, an optical distance-limited reflection type sensor 16 is used as the notch alignment sensor. By operating the wafer holding means 13, the sensor 16 is moved to a position where the sensor 16 can detect the notch 17 of the wafer 7 when the wafer rotating means 12 rotates. The center of the notch 17 is the sensor
The position can be easily determined as an intermediate position between the position data of the wafer rotating unit 12 at which the detection of the notch 17 has been started and the position data of the wafer rotating unit 12 at which the detection has been completed (see FIG. 8).

When the reflection type sensor 16 for notch sensing is used for the wafer edge detection means 14, the first and second wafer edge detection steps and the second rotation step for notch alignment are all performed in one step.
This can be done with a number of sensors (see FIG. 6). Further, it can be used as a presence confirmation sensor for confirming the presence state of the wafer 7 placed on the wafer holding means 13 (see FIG. 7). Thus, the distance-limited reflection type sensor 16
In the case where only one of them is used, the sensor 16 may be provided at a position where the wafer 7 can be detected on a line passing through the center of the wafer center existence line Y1 and orthogonal thereto (see FIG. 6).

Next, an alignment method for a wafer with an orientation flat according to the fourth embodiment will be described. Also in this alignment method, one optical distance limited reflection type sensor 16 described in the notch alignment is used. Wafer rotating means
Until the second mounting process, in which the center of the wafer is centered on the rotation axis of 12,
This is the same as the content described above. After the second mounting step, the sensor 16 is operated by operating the wafer holding means 13 to move the sensor 16 near both ends of the orientation flat 18 of the wafer 7 mounted and rotated on the wafer rotating means 12 as shown in FIG. Is moved to a position where it can be sensed, that is, OFF at the orientation flat position, and to a position where it becomes an ON region where the wafer 7 is detected otherwise, and waits.

Then, for example, a servo motor or the like is used as a drive source of the wafer rotating means 12 to change from ON to OFF or O
The position of the encoder provided in the wafer rotating means 12 at the time of sensor output when the signal changes from FF to ON is read.
The angle (phase) can be adjusted by considering the intermediate value of the values near both ends of the orientation flat 18 as the median value of the orientation flat 18. Also in this case, the reflection type sensor 16 is connected to the wafer edge detecting means 14.
, The first and second wafer edge detection steps and the second rotation step of aligning the orientation flat can all be performed by one sensor. Furthermore, it can be used as a presence confirmation sensor for confirming the presence state of the wafer 7 placed on the wafer holding means 13. That is, by providing one of the reflection type sensors 16 in the wafer holding means 13, not only the center alignment of the wafer 7 but also the phase alignment of the notch 17 or the orientation flat 18 can be easily performed. It can also be used as a presence confirmation sensor when held by the means 13.

As described above, in the fourth embodiment, in addition to the wafer alignment (center alignment), the notch 17 of the wafer 7 or the phase alignment of the orientation flat 18 (second
Since the rotation step) is also performed, the detection and control for wafer alignment is performed by detecting the wafer edge twice by the wafer edge detecting means 14 during the access operation of the wafer holding means 13 to the wafer 7. A predetermined angle of the first wafer rotating means 12 between the first and second movement amount correction control of the wafer holding means 13 based on the information on the wafer edge position to be obtained. (90 °) Only the rotation amount control and the second rotation amount control of the wafer rotating means 12 for positioning the notch 17 or the orientation flat 18 of the wafer 7 are performed. The configuration of the control unit is simplified,
It is easy and inexpensive, and eliminates the need for complicated and expensive data processing line sensors and imaging means that have been indispensable for conventional wafer alignment.
Alternatively, it is possible to reduce the cost of the entire wafer transfer apparatus 10 used for performing the wafer alignment method including the phase alignment of the orientation flat 18.

Next, an embodiment (Embodiment 5) of the invention described in claim 12 of the present application shown in FIGS. 10 to 12 will be described. FIG. 10 shows an optical transmission type sensor 19 provided in the wafer holding unit 13 when the wafer holding unit 13 of the wafer transfer device 10 used for performing the wafer alignment method in the fifth embodiment enters the FOUP 6.
FIG. 11 is a side sectional view for explaining a state in which the optical axis 19a of the sensor 19 detects the edge of the wafer 7, and FIG.
19a detects the edge of the wafer 7, the wafer holding means 13
FIG.
2 is the notch of the wafer 7 when the optical axis 19a of the transmission type sensor 19 is
FIG. 9 is a perspective view illustrating a state in which a signal 17 is detected.

In the wafer alignment method according to the fifth embodiment, as shown in FIGS. 10 to 12, the wafer edge detection means 14 is an optical transmission type sensor 19.
The transmission type sensor 19 is provided at the base of the wafer holding section of the wafer holding means 13 with its optical axis 19a substantially vertical, and detects the edge of the wafer 7.

When the sensor 19 is arranged in this manner, after the above-described first wafer edge detection, the wafer holding means 13 needs to be moved backward to a position where it does not interfere with the wafer 7 located above the target wafer 7. . Assuming that the wafer holding means 13 is retracted by a certain distance from the first wafer edge detection position, the wafer holding means 13 is retracted, raised, and moved by a predetermined distance to complete the first mounting step. After that, the above-described steps are sequentially performed, and alignment work such as notch phase alignment and orientation flat alignment (not shown) is performed in the second rotation step.

When the reflection type sensor is used, the retreating operation is not always required, and the presence sensor of the wafer holding means 13 can be used as well. However, when the transmission type sensor 19 is used, the film or color on the wafer surface can be reduced. Is not affected at all, and high-precision alignment can be realized as compared with the reflection type sensor. For the transmission type sensor 19, an optical axis 19a having a small optical axis 19a, preferably having a size of 0.2 mmφ or less is used. When higher accuracy is required, a transmission type line sensor or the like may be provided.

Next, an embodiment (Embodiment 6) of the invention described in claims 13 to 16 of the present application shown in FIGS. 13 to 18 will be described. FIG. 13 shows a position at which the wafer holding means 13 of the wafer transfer device 10 used to carry out the wafer alignment method in the sixth embodiment accesses the target wafer 7 in order to detect the storage height position of the target wafer 7. Wafer 7
FIG. 14 is a plan view for explaining that the target wafer 7 has a shape that does not come into contact with the target wafer 7. FIG. 15 is a sectional side view for explaining the detection of the storage height position including the upper and lower wafers 7, 7, and FIG. FIG. 16 is a side sectional view of FIG. 15, and FIG. 17 is a plan view showing a state in which the means 13 detects a wafer edge. FIG. 18 is a cross-sectional side view of FIG. 17, showing a state where the vehicle 7 has entered the space and the presence confirmation sensor provided in the wafer holding means 13 confirms the presence of the wafer 7.

In the wafer transfer means 11 of the wafer transfer apparatus 10 used for carrying out the wafer alignment method according to the sixth embodiment, the wafer edge detecting means 14 comprises an optical transmission sensor 20. The sensor 20 is provided at the tip of the wafer holding portion of the wafer holding means 13 with its optical axis 20a substantially horizontal, and detects the edge position of the wafer 7 and the storage height position of the wafer 7. Further, a mapping function for mapping the storage state of the wafer 7 is provided. The front end portion of the wafer holding portion of the wafer holding means 13 is cut off in an L-shape in plan view on the opposite inner surface side,
The shape is such that it does not contact the protruding wafer 7 (see the L-shaped cut-out portion 23 in FIGS. 13, 15, and 17).

Further, the wafer transfer means 11
Wafer presence detecting means for detecting the presence of the wafer, and the wafer presence detecting means comprises an optical reflection sensor 21.
The reflection sensor 21 is provided at the base of the wafer holding section of the wafer holding means 13 to detect the vicinity of the edge of the wafer 7.

Since the wafer alignment method of the sixth embodiment is performed using the wafer transfer device 10 configured as described above, the following effects can be obtained. The transmission sensor 20 can be used to detect the edge of the wafer 7, and the reflection sensor 21 can be used to detect the presence of the wafer 7 and the notch 17 or the orientation flat 18 of the wafer 7, whereby the wafer 7 can be detected. Performing the first and second wafer edge detection steps for centering, confirming the presence of the wafer 7, and performing these detections in a second rotation step for aligning the notch 17 or orientation flat 18 of the wafer 7 Can be. In this case, since the transmission sensor 20 detects the wafer edge, the detection accuracy of the wafer edge can be kept high. In the transmission sensor 20,
Although the wafer presence confirmation function as an interlock function when the wafer holding means 13 holds and moves the wafer 7 cannot be used, the reflection type sensor 21 can also use this function.

The transmission type sensor 20 has its optical axis 20a substantially horizontal and is provided at the tip of the wafer holding portion of the wafer holding means 13, so that its optical axis 20a is substantially vertical and The wafer holding means 13 is retracted even if the upper wafer 7 of the wafer 7 whose edge is to be detected is protruding, as compared with the case where the wafer is provided at the base of the wafer holding portion of the holding means 13 (Embodiment 5). In addition, the wafer 7 to be detected can be lifted and taken out, and the work of taking out the wafer 7 can be simplified.

Further, since the transmission type sensor 20 detects the edge position of the wafer 7 and the storage height position of the wafer 7, the FO in which the dimensional deviation, distortion, twist, etc. due to the aging change occur.
Even if the storage height position of the wafer 7 varies in the UP 6 or the cassette, the storage height position of the wafer 7 can be accurately grasped before the wafer holding means 13 enters the gap between the upper and lower wafers 7. Therefore, the wafer holding unit 13 can access the detection target wafer 7 at an appropriate height position corresponding to the storage height position of the wafer 7. Generally, in the case of a 300 mm FOUP, the gap between the upper and lower wafers 7 is about 9 mm. In addition to distortion and torsion of FOUP6 and wear of positioning reference part, FOUP6
6. Considering the variation during molding, as well as the warpage and bending of the wafer 7 itself, the height of the tip of the wafer 7 on the side where the wafer holding means 13 enters may vary by about ± 2 mm. In addition, the amount of variation increases with time. Then, the wafer holding means 13 is used for the upper and lower wafers 7, 7
As described above, it is important to detect the storage height of the wafer 7 and to set the access height of the wafer holding means 13 to an appropriate height before entering the gap between them, as described above. When the storage height information is received as mapping information from another mapping mechanism provided in advance, the operation of the transmission sensor 20 as described above is not required.

Further, even if the wafer 7 slightly protrudes, the edge position of the wafer 7 can be grasped with high accuracy by the transmission type sensor 20. The wafer holding means 13 can be stopped by accessing the wafer 7 to be detected. Thus, when the wafer holding means 13 accesses the wafer 7 to be detected, the wafer 7 and the upper and lower wafers 7 adjacent to the wafer 7 are not damaged.

Further, since the transmission type sensor 20 has a mapping function for mapping the storage state of the wafer 7, the transmission type sensor 20 is provided with the edge position of the wafer 7, the storage height position, and the upper and lower wafers. It is possible to detect not only the gap between 7, 7 but also the state such as the presence / absence of the wafer 7, so that the storage state of the wafer can be comprehensively understood. This allows not only wafer alignment,
A wafer alignment method that can also perform wafer mapping can be realized.

Next, an embodiment (Embodiment 7) of the invention described in claims 17 and 18 of the present application shown in FIGS. 19 and 20 will be described. FIG. 19 shows that the wafer holding unit 13 of the wafer transfer apparatus 10 used for carrying out the wafer alignment method in the seventh embodiment is
FIG. 20 is a side view for explaining a process of mapping a plurality of aligned wafers 7 in P. FIG. It is a side view explaining the process of.

The wafer transfer device 10 with an alignment function used for carrying out the wafer alignment method according to the seventh embodiment has substantially the same structure as the wafer transfer device 10 according to the first embodiment. Then, in addition to the point where the wafer edge detection means 14 is provided at the tip of the wafer holding portion of the wafer holding means 13 and the edge of the wafer 7, the wafer edge detection means 14 is also configured to perform mapping of the wafer 7. Are different. That is, the wafer edge detecting means 14 in the seventh embodiment is composed of an optical transmission type sensor 22, the optical axis of which is substantially horizontal, and the wafer holding section 13 of the wafer holding means 13. The edge of the wafer 7 is detected, and the mapping of the wafer 7 is performed.

The wafer alignment method according to the seventh embodiment, which is performed using such a wafer transfer device 10 having an alignment function, includes at least the following steps. First, the wafer holding means 13 is lowered in the vicinity of the edge of the wafer 7, and the wafer 7 is mapped by the transmission type sensor 22 serving as the wafer edge detection means 14, whereby the height position of the wafer 7 is determined. Detect (wafer height direction position detection step). Next, the wafer holding means 13 is horizontally moved in the forward direction at the height position of the wafer 7 detected in the wafer height direction position detection step, and the transmission type sensor is moved.
At 22, the edge of the wafer 7 is detected (wafer edge detection step). Next, the wafer holding means 13 is lowered to avoid interference with the wafer 7, and then horizontally moved again in the forward direction, and the wafer holding means 13 is moved based on the wafer edge position information obtained in the wafer edge detection step. The wafer is stopped at the wafer holding target position below 7 (wafer holding target position stopping step). Finally, the wafer holding means 13 is raised and the wafer holding means 13
Picks up the wafer 7, holds it, and then retreats it, and transfers the wafer 7 to the wafer rotating means 12 or the processing chamber (wafer holding / transfer step).

Since the wafer alignment method according to the seventh embodiment is configured as described above, when the wafer holding means 13 accesses the target wafer 7, the wafer 7 and the upper and lower wafers 7 adjacent to the wafer 7 7
The operation required for wafer alignment and wafer transfer can be executed in a short time through the shortest distance without damaging the wafer. In addition, the transmission type sensor 22
Can detect and map the edge of the wafer 7 with high accuracy,
In addition, the operation can be performed efficiently with one operation by the downward movement of the wafer holding means 13.

[Brief description of the drawings]

FIG. 1 is a diagram showing a layout of an entire wafer processing facility using a wafer transfer apparatus according to an embodiment (Embodiment 1) of the invention described in claims 1 to 6 and 19 of the present application; .

FIG. 2 is a plan view showing a state in which a wafer contained in a FOUP is misaligned.

FIG. 3 is a side sectional view of FIG. 2;

FIG. 4 is a plan view illustrating a state in which a wafer holding unit enters the FOUP and an optical axis of a transmission sensor provided in the wafer holding unit detects a wafer edge;

FIG. 5 is a partial side view of FIG. 4;

FIG. 6 is a schematic view showing a wafer transfer device used in carrying out a wafer alignment method according to an embodiment (Embodiment 4) of the present invention described in claims 9 to 11; FIG. 9 is a plan view illustrating a state where an optical axis of an optical distance-limited reflection type sensor provided on a wafer holding unit detects a wafer edge.

FIG. 7 is a side sectional view of FIG. 6;

FIG. 8 is a perspective view illustrating a state where the optical axis of the reflection type sensor detects a notch.

FIG. 9 is a perspective view illustrating a state where the optical axis of the reflection type sensor detects an orientation flat.

FIG. 10 is a perspective view of a wafer transfer apparatus according to an embodiment (Embodiment 5) of the present invention;
FIG. 7 is a side cross-sectional view illustrating a state in which the optical axis of an optical transmission sensor provided in the wafer holding unit enters the P and detects an edge of the wafer.

FIG. 11 illustrates a state in which, after the optical axis of the transmission sensor detects the edge of the wafer in FIG. 10, the wafer holding means has receded outside the interference area of another wafer to pick up the wafer and has risen. FIG.

FIG. 12 is a perspective view illustrating a state in which the optical axis of the transmission sensor detects a notch in the wafer.

FIG. 13 is a plan view of a wafer transfer device used in carrying out a wafer alignment method according to an embodiment (Embodiment 6) of the invention described in claims 13 to 16 of the present invention; FIG. 9 is a plan view showing a position where the target wafer is accessed to detect the position, and explaining that the target wafer is formed so as not to contact the protruding wafer.

FIG. 14 illustrates that the wafer holding unit detects the storage height position including the wafers above and below the target wafer in order to confirm the storage height position of the target wafer and the gap between the wafer vertically adjacent thereto. It is a sectional side view explaining.

FIG. 15 is a plan view showing a state in which the wafer holding unit is retracted in accordance with the storage height position of the target wafer, and the wafer holding unit 13 detects a wafer edge.

FIG. 16 is a side sectional view of FIG.

FIG. 17 is a plan view showing a state in which the wafer holding means has entered between the target wafer and the wafer located therebelow, and the presence check sensor provided on the wafer holding means has checked the presence of the wafer; It is.

FIG. 18 is a side sectional view of FIG. 17;

FIG. 19 is a perspective view of a wafer transfer device used in carrying out a wafer alignment method according to an embodiment (Embodiment 7) of the invention described in claims 17 and 18 of the present invention; It is a side view explaining the process of performing mapping of a plurality of wafers.

FIG. 20 is a side view illustrating a process in which a wafer holding unit accesses a target wafer, detects a wafer edge, and picks up the target wafer 7;

[Description of Signs] 1 ... Wafer processing equipment, 2 ... Front end, 3 ... Wafer processing apparatus, 4 ... Wafer supply unit, 5 ... FOUP opener,
6 FOUP, 7 semiconductor wafer, 10 wafer transfer device, 11 wafer transfer means, 12 wafer rotation means (rotary table), 13 wafer holding means (robot arm), 13
a ... first arm, 13b ... second arm, 13c ... hand part (third arm), 14 ... wafer edge detecting means (transmission sensor, reflection sensor), 14a ... optical axis, 15 ... track, 16 ... Reflection type sensor, 16a ... optical axis, 17 ... notch, 18 ... orientation flat, 19
… Transmissive sensor, 19a… Optical axis, 20… Transmissive sensor, 20a
... Optical axis, 21 ... Reflective sensor, 22 ... Transmissive sensor, 23 ... L
Character cutout, A: area, Y1: first center existence line.

Claims (19)

[Claims] 1. A wafer transfer device with an alignment function for aligning a semiconductor wafer and transferring it to a processing device comprises a wafer transfer means and a wafer rotation means, wherein the wafer transfer means holds and transfers the wafer. A wafer holding means, and a wafer edge detecting means for detecting an edge of the wafer, wherein the wafer rotating means is provided in an area where the wafer transfer means can place a wafer, and And a wafer transfer device with an alignment function. 2. The wafer transfer device with an alignment function according to claim 1, wherein a plurality of the wafers are horizontally stored at predetermined intervals in a container or a cassette. 3. The wafer edge detecting means comprises an optical transmission type sensor, and the transmission type sensor has an optical axis substantially horizontal and is provided at a base of a wafer holding portion of the wafer holding means. 3. The wafer transfer device with an alignment function according to claim 1, wherein an edge of the wafer is detected. 4. A wafer alignment method for aligning the wafer using the wafer transfer device with an alignment function according to claim 1, wherein at least the following steps are performed: A first wafer edge detecting step in which the wafer transfer means is moved and the wafer edge detecting means detects an edge of the wafer; a first wafer edge position obtained in the first wafer edge detecting step A first mounting step of correcting and controlling a moving distance of the wafer holding means based on the information, and mounting the wafer on the wafer rotating means; a first rotating step of rotating the wafer rotating means by a predetermined angle; A second wafer edge detecting step of moving the wafer transfer means and detecting the edge of the wafer placed on the wafer rotating means by the wafer edge detecting means; The moving distance of the wafer holding means is corrected and controlled based on the second wafer edge position information obtained in the second wafer edge detecting step, and the wafer is moved to a predetermined position of the wafer rotating means and re-moved. A second mounting / transfer step of mounting or transferring directly to the processing chamber. 5. The first mounting step is such that a center existence line Y1 of the wafer detected in the first wafer edge detection step is orthogonal to a rotation axis of the wafer rotation means.
The first rotating step is such that the wafer edge on the center existing line Y1 of the wafer is detected by the wafer edge detecting means. 5. The method according to claim 4, further comprising the step of rotating the wafer rotating means. 6. The first mounting step and the second mounting step.
In the transfer step, the wafer holding unit rotates the wafer by the wafer rotating unit to correct and control the moving distance of the wafer holding unit based on the first wafer edge position information and the second wafer edge position information. 5. The wafer alignment method according to claim 4, wherein the position of the wafer is corrected and controlled. 7. The first mounting step and the second mounting step.
In the transfer step, the position at which the wafer holding unit picks up the wafer is corrected to control the correction of the moving distance of the wafer holding unit based on the first wafer edge position information and the second wafer edge position information. 5. The wafer alignment method according to claim 4, wherein the control is performed. 8. The wafer alignment method according to claim 7, wherein the position where the wafer holding unit picks up the wafer is a position where the movement of the wafer holding unit is stopped at the time of detecting a wafer edge. . 9. A wafer alignment method for aligning the wafer using the wafer transfer device with an alignment function according to claim 1 or 2, wherein at least the following step, that is, the wafer transfer means In the first wafer edge detecting step of detecting the edge of the wafer by the wafer edge detecting means, and based on the first wafer edge position information obtained in the first wafer edge detecting step. A first mounting step of correcting and controlling a moving distance of the wafer holding means to mount the wafer on the wafer rotating means, a first rotating step of rotating the wafer rotating means by a predetermined angle, A second wafer edge detection step of moving the transfer means and detecting the edge of the wafer placed on the wafer rotating means by the wafer edge detection means; The movement distance of the wafer holding means is corrected and controlled based on the second wafer edge position information obtained in the edge detection step, and the wafer is moved to a predetermined position of the wafer rotating means and remounted. A second mounting step, wherein a notch or an orientation flat of the wafer re-mounted on the wafer rotating means is detected by the wafer edge detecting means, and this is positioned at a predetermined position of the wafer rotating means. And a rotating step. 10. The wafer alignment method according to claim 9, wherein said wafer edge detecting means comprises an optical distance-limited reflection type sensor. 11. The wafer alignment method according to claim 9, wherein said wafer rotating means is driven by a servomotor capable of numerical control. 12. The wafer edge detection means comprises an optical transmission type sensor, and the transmission type sensor is provided at a base of a wafer holding portion of the wafer holding means, with an optical axis thereof being substantially vertical. 10. The wafer alignment method according to claim 9, wherein an edge of the wafer is detected. 13. The wafer edge detecting means comprises an optical transmission type sensor, and the transmission type sensor has an optical axis substantially horizontal, and is provided at a tip end of a wafer holding portion of the wafer holding means. 10. The wafer alignment method according to claim 9, wherein an edge of the wafer is detected. 14. The wafer alignment method according to claim 13, wherein the transmission sensor detects at least an edge position of the wafer and a storage height position of the wafer. 15. The apparatus according to claim 13, wherein the transmission type sensor has a mapping function for mapping a storage state of the wafer.
5. The wafer alignment method according to 4. 16. The wafer edge detecting means comprises an optical transmission type sensor, wherein the transmission type sensor has an optical axis substantially horizontal, and is provided at a tip end of a wafer holding portion of the wafer holding means. A wafer presence detecting means for detecting an edge of the wafer, further comprising a wafer presence detecting means for detecting the presence of the wafer, wherein the wafer presence detecting means comprises an optical reflection type sensor. 10. The wafer alignment method according to claim 9, wherein the reflection sensor is provided at a base of a wafer holding unit of the wafer holding unit, and detects a vicinity of an edge of the wafer. 11. . 17. A wafer alignment method for aligning the wafer using the wafer transfer device with the alignment function according to claim 1 or 2, wherein at least the following step, that is, the wafer holding means A wafer height direction position detecting step of lowering the vicinity of the end of the wafer, mapping the wafer by the wafer edge detecting means, and detecting a height direction position of the wafer; In the forward direction at the height position of the wafer detected in the wafer height direction position detection step, and detecting the edge of the wafer by the wafer edge detection means And lowering the wafer holding means to avoid interference with the wafer, and then horizontally moving again in the forward direction, A wafer holding target position stopping step of stopping at a lower wafer holding target position of the wafer based on the wafer edge position information obtained in the wafer edge detecting step; Holding the wafer and then retracting the wafer to transfer the wafer to the wafer rotating means or the processing chamber. 18. The wafer edge detecting means comprises an optical transmission type sensor, wherein the transmission type sensor has an optical axis substantially horizontal, and is provided at a tip end of a wafer holding portion of the wafer holding means. 18. The wafer alignment method according to claim 17, wherein an edge of the wafer is detected and mapping of the wafer is performed. 19. The wafer transfer device with an alignment function according to claim 1, wherein the wafer transfer means includes a horizontal linear movement mechanism configured to move the wafer holding means substantially horizontally and substantially linearly. An elevation mechanism for elevating and lowering the horizontal linear movement mechanism, and a turning mechanism for turning the horizontal linear movement mechanism. Being driven, the wafer rotating means having a suction means for holding the wafer, and being arranged within a rotation radius of the wafer holding means on a movement locus of the wafer holding means by the horizontal linear movement mechanism. The wafer transfer means and the wafer rotation means are provided on a numerically controllable carrier moving on a track, and an opener and It alignment function with the wafer transfer device according to claim being the front-end structure section that is provided controlled space for transferring the wafer between the physical room.