JP2008270474A - Pre-aligner device, transport system including the same, and semiconductor manufacturing device - Google Patents

Abstract

In a pre-aligner for adjusting the position of a semiconductor wafer, particles generated from the drive unit are prevented from adhering to the wafer. A drive unit for rotating a wafer stage and a machine for storing the drive unit In the pre-aligner apparatus including the frame 21, one end is connected to the wafer stage 27, the other end is connected to the driving unit, and the shaft 24 is rotatably supported on the upper plate of the machine frame 21. The impeller 11 provided on the shaft 24 is provided, and the impeller 11 is provided so that an airflow is generated in a direction away from the wafer stage 27 when the shaft 24 is rotated by the driving unit.
[Selection] Figure 1

Description

  The present invention relates to a pre-aligner that adjusts the position of a semiconductor wafer, and more particularly to a mechanism that prevents particles generated from the drive mechanism from adhering to the wafer.

In semiconductor manufacturing equipment, etc., a pre-aligner device is mainly used in combination with a wafer handling robot, and grips (grips) a wafer transferred from the robot and rotates the wafer to preliminarily make an outer periphery. This is a device that detects notches such as or flats and aligns them in a predetermined angular direction based on this, and determines the center position of the wafer itself (centering). This pre-aligner device is used for wafer handling in a box with a downflow airflow that has passed through a filter, that is, in a locally cleaned case, in a semiconductor manufacturing process that does not like dust in recent semiconductor manufacturing devices. Installed with the robot. A cassette opener (POD opener or FOUP opener) that opens and closes a cassette (such as FOUP) that contains wafers is provided on the side of the case, and this opener allows a clean atmosphere outside the case to enter the case. The cassettes are opened and closed without any change. Then, the wafer handling robot places the wafer in the cassette on the pre-aligner, and transports the aligned wafer to a processing apparatus installed adjacent to the housing. In the processing apparatus, predetermined processing such as CVD, etching, exposure, and the like is performed. Then, the wafer that has been processed by the processing apparatus is again stored in the cassette by the wafer handling robot. A housing that houses such equipment is called a front-end device or a transport system. In addition, a plurality of cassette openers are provided on the side of the case, and a case is also developed in which a wafer handling robot moves wafers while aligning with a pre-aligner between multiple cassettes on the plurality of cassette openers. ing. This housing is a conveying device called a sorter or the like.

Thus, since the pre-aligner carries the wafer into or out of the processing apparatus together with the robot, or transfers the wafer, a frequent operation occurs. If the operation occurs, particles are generated from the drive mechanism, and if it is placed on the wafer, it adversely affects semiconductor manufacturing. The pre-aligner and the robot are configured to exist under a gentle air flow. Due to this air flow, particles generated by a drive mechanism such as a pre-aligner are caused to flow to the lower part of the housing, and the particles are not placed on the wafer.

The configuration of the pre-aligner described above will be described with reference to FIG. 2, FIG. 3, and FIG. 2 to 4 are side sectional views showing a driving mechanism of a conventional pre-aligner. 3 and 4 are cross-sectional views showing a driving mechanism in which particle scattering preventing means described later is provided in the driving mechanism of FIG.
In FIG. 2, reference numeral 21 denotes a pre-aligner machine frame, and reference numeral 22 denotes a drive motor fixed to the machine frame 21. Reference numeral 23 denotes a driving pulley fixed to the rotating shaft of the driving motor 22, and 24 denotes a shaft that is inserted into a bearing (not shown) provided in the machine frame 21 and rotatably supported. The rotational force of the driving pulley 23 is applied to the lower end. A driven pulley 5 that rotates via a timing belt 26 is provided, and a wafer stage 27 for mounting a wafer is provided at the other end (upper end). The wafer stage 27 is provided with a wafer suction device (not shown) for vacuum-sucking the wafer 28 or a wafer gripping means (not shown) for gripping the outer periphery of the wafer 28. When the shaft 24 rotates, the wafer 28 is configured to rotate simultaneously.

Next, the operation of the conventional pre-aligner driving mechanism will be described.
The wafer 28 that requires alignment is mounted on the wafer stage 27 by a wafer transfer device (wafer handling robot) (not shown). The mounted wafer 28 is fixed on the wafer stage 27 so as not to be displaced by a wafer suction device (not shown) or a wafer gripping means (not shown) for gripping the outer periphery of the wafer. When an operation command is given to the motor 22 from a pre-aligner control device (not shown) and the motor 22 rotates, the rotational force of the motor 22 is transmitted to the shaft 24 via the drive pulley 23, the belt 26 and the driven pulley 25. When the shaft 24 rotates, the wafer stage 27 rotates, and the wafer 28 mounted on the wafer stage 27 rotates. When the wafer 28 rotates by a predetermined amount, the sensor 29 detects the position of the outer peripheral portion of the wafer 28, the amount of deviation of the center position of the wafer 28 from the reference axis, and a notch or an oriental flat (oriental flat) provided on the outer peripheral portion of the wafer 28. The position of is detected. Information on the detected center position shift amount and notch position of the wafer 28 is transmitted to a pre-aligner control device (not shown). The pre-aligner control device processes the above-mentioned information and notifies the deviation amount to a control device of a wafer transfer device (not shown). The pre-aligner controller rotates the motor 22 and moves the notch of the wafer 28 to a predetermined position. A control device of the wafer transfer device (not shown) instructs the transfer device to operate the drive mechanism of the transfer device, so that the center position of the wafer 28 coincides with the reference axis of the hand of the transfer device, and the transfer device removes the wafer 28 from the wafer. Operate to receive from stage 27. At this time, before the wafer transfer device (not shown) receives the wafer 28 from the wafer stage 27, a wafer suction device (not shown) provided so as not to shift the mounting position on the wafer stage 27, or to hold the outer periphery of the wafer. The wafer gripping means (not shown) is unlocked (not gripped). The wafer alignment operation is performed by the above means.
In some cases, the control device of the pre-aligner device and the control device of the wafer transfer device are integrally configured. In addition, when the gripping means provided on the wafer stage 27 is configured to grip the wafer 28 and simultaneously align the center position thereof, the wafer transfer device performs only the operation of transferring the wafer 28 to the pre-aligner.

However, according to the conventional pre-aligner as shown in FIG. 2, particles generated from driving units such as the motor 22, the belt 26, and the driven pulley 25 are scattered from the gap 13 between the machine frame 21 and the shaft 24 when the wafer 28 is rotated. In some cases, it may adhere to the wafer 28.
Therefore, in order to prevent particles scattered from the drive unit via the gap 13 from adhering to the wafer 28, the fan 30 shown in FIG. A structure that uses a structure or a magnetic fluid seal 41 shown in FIG. 4 to prevent particles from scattering outside the machine casing 21 has been adopted. The fan 30 is provided to discharge the gas inside the machine casing 21 toward the lower surface of the machine casing 21, and the magnetic fluid seal 41 is fixed to the upper surface of the machine casing 21 and provided concentrically with the shaft 24. This is a known seal. That is, conventionally, particle scattering is prevented by means of particle scattering prevention means such as these fans and magnetic fluid seals.
However, the fan 30 and the magnetic fluid seal 41 are generally expensive, which increases the cost of the product, and increases the assembly man-hours and hinders the degree of freedom in arranging the parts of the drive unit.
In addition, the fan 30 always needs electric power, and it is necessary to arrange electric wiring therefor.
Therefore, the present invention has been made in view of such problems, and it is possible to prevent adhesion of particles to the wafer, reduce the number of parts, and realize high reliability, compactness, and low price. The aim is to provide an aligner.

In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 is a wafer stage on which a semiconductor wafer is mounted, a drive unit that rotates the wafer stage, a machine frame that houses the drive unit, and an outer peripheral portion of the semiconductor wafer that is rotated by the drive unit. A pre-aligner device for rotating the semiconductor wafer to a desired position in accordance with information on the outer peripheral portion detected by the sensor, one end of which is connected to the wafer stage and the other end is A shaft connected to the drive unit and rotatably supported by an upper plate of the machine frame; and an impeller provided on the shaft inside the machine frame, the shaft being rotated by the drive unit A pre-aligner device, wherein the impeller is provided so that an airflow is generated in a direction away from the wafer stage when It was.
According to a second aspect of the present invention, the impeller is provided on the shaft so as to be positioned between the drive unit and a position immediately below a gap between the upper plate of the machine frame and the shaft. 2. The pre-aligner according to claim 1, wherein the pre-aligner is provided so as to generate the airflow toward the lower part inside the machine frame while taking in the gas in the upper part of the upper plate from the gap. .
According to a third aspect of the present invention, the drive unit includes: a motor fixed to the machine casing; a drive pulley provided on a rotation shaft of the motor; a driven pulley connected to the other end of the shaft; A pulley wound around the drive pulley and the driven pulley, and the impeller is at least above the driven pulley and has a rotation diameter equal to or greater than the diameter of the passive pulley. The pre-aligner according to claim 2, wherein the pre-aligner is provided.
According to a fourth aspect of the present invention, in the pre-aligner apparatus according to the first aspect, at least a portion of the lower surface of the machine casing corresponding to the lower side of the shaft is made of a punching metal capable of discharging the airflow. did.
According to a fifth aspect of the present invention, the machine frame is configured such that a side surface of the upper plate and the machine frame is hermetically sealed in addition to a gap at a location where the shaft is rotatably supported on the upper plate of the machine frame. The pre-aligner device according to claim 1 is provided.
According to a sixth aspect of the present invention, the pre-aligner device according to the first aspect, a robot for transporting the semiconductor wafer, the robot and the pre-aligner device are accommodated, and a filter is provided on the upper portion to provide a clean air flow. A wafer transfer system comprising a local clean housing for downflowing to a robot and the pre-aligner device.
A seventh aspect of the present invention provides a semiconductor manufacturing apparatus including the wafer transfer system according to the sixth aspect.

According to the first aspect of the present invention, the impeller is attached to the rotating shaft to which the wafer mounting portion (wafer stage) is attached, so that the impeller rotates in synchronization with the rotation of the wafer. Since the surrounding air is made to flow in the direction opposite to the wafer (in the direction away from the wafer), there is an effect that particles generated from the drive unit of the rotating shaft are not attached to the wafer. Therefore, it is possible to prevent particles from adhering to the wafer without providing an electric fan for negative pressure inside the machine frame and a magnetic fluid seal for preventing particles from scattering outside the machine frame. Therefore, a low-cost and compact configuration can be achieved.
According to the second aspect of the present invention, the particles of the drive unit can be moved away from the wafer while taking in the gas at the upper part of the machine frame upper plate, so that the flow of airflow from the top to the bottom is not hindered, and the effect Particles can be moved away.
According to the third aspect of the present invention, the particles can be effectively moved away from the wafer with respect to the operation of the driven pulley that is closest to the wafer and in which particles are likely to adhere to the wafer.
In the fourth aspect of the present invention, since the lower portion of the machine frame is formed with at least a punching metal on the lower surface of the machine frame, the airflow generated by the impeller is discharged below the pre-aligner device while being rectified by the punching metal. The particles can be reliably moved away from the wafer. Further, if at least a portion corresponding to the lower part of the shaft is formed by punching metal, the above-described effects can be obtained while ensuring the rigidity as the machine frame.
According to the fifth aspect of the invention, since the upper plate and the side surface of the machine frame are sealed except for the gap necessary for the rotation of the shaft, the particles moved away by the air current are prevented from adhering to the wafer again.
According to a sixth aspect of the present invention, if the pre-aligner according to the first aspect is installed in a locally clean case having a downflow, at least the pre-aligner apparatus prevents particles from adhering to the wafer, and a highly clean wafer transfer system. Can be configured.
Since the invention described in claim 7 is a semiconductor manufacturing apparatus that transfers a wafer using the wafer transfer system described in claim 6, it is difficult for particles to adhere to the wafer, and the apparatus can improve the yield in semiconductor manufacturing. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

A specific embodiment of the present invention will be described below with reference to FIG.
FIG. 1 is a side sectional view showing a drive mechanism for a pre-aligner embodying the present invention. The same mechanisms as those in the prior art are given the same numbers as in FIG.
21 is a machine frame of a pre-aligner and has a box shape. A drive motor 22 is fixed inside the machine casing 21. 23 is a drive pulley fixed to the rotation shaft of the drive motor 22; 24 is a shaft that is rotatably supported by a bearing (not shown) provided on the upper plate of the machine frame 21 and penetrates into the machine frame 21; A driven pulley 25 that rotates the rotational force of the drive pulley 23 via a timing belt 26 is provided at the lower end, and a wafer stage 27 for mounting a wafer 28 is provided at the other end. The wafer stage 27 is provided with a wafer suction device (not shown) for vacuum-sucking the wafer 28 or a wafer gripping means (not shown) for gripping the outer periphery of the wafer 28. When the shaft 24 rotates, the wafer 28 is configured to rotate simultaneously. A sensor 29 detects the shape of the outer peripheral portion of the rotating wafer 28.

In the present invention, the impeller 11 is provided on the shaft 24. The impeller 11 rotates at the same time as the shaft 24 rotates, and the angle of the impeller is adjusted so that an airflow is generated in a direction opposite to the position of the wafer 28, that is, an airflow is generated toward the lower surface of the machine casing 21. It is set. No power is supplied to the impeller 11, thereby preventing the impeller 11 from rotating by itself. The impeller 11 is provided so as to be almost directly below the gap 13 between the shaft 24 and the upper surface of the machine casing 21, and so as to be positioned above the driven pulley 25. In this embodiment, the impeller 11 has a rotational diameter that is the same as or slightly larger than the diameter of the driven pulley 25.
Furthermore, in the present invention, the lower surface of the machine casing 21 is made of the punching metal 12. The punching metal 12 is a plate formed by punching holes (holes) with a diameter of several millimeters in a metal plate or the like with a punching press die. In this invention, it manufactures with metal plates, such as a steel plate, a stainless steel plate, and an aluminum plate. The hole in the punching metal 12 penetrates into the machine casing 21. In FIG. 1, the punching metal 12 is provided on the entire lower surface of the machine casing 21. Moreover, the hole of the punching metal 12 has a hole diameter and a hole arrangement density so that particles once jetted to the outside of the lower surface of the machine frame 21 by the air flow created by the impeller 11 do not enter the machine frame 21 again. Is set.

Next, the operation of the pre-aligner driving mechanism of the present invention will be described.
The wafer 28 requiring alignment is mounted on the wafer stage 27 by a transfer device (wafer handling robot) (not shown). The mounted wafer 28 is fixed on the wafer stage 27 so as not to be displaced by a wafer suction device (not shown) or a wafer gripping means (not shown) for gripping the outer periphery of the wafer. When an operation command is given to the motor 22 from a pre-aligner control device (not shown) and the motor 22 rotates, the rotational force of the motor 22 is transmitted to the shaft 24 via the drive pulley 23, the belt 26 and the driven pulley 25. Is done. Then, the wafer stage 27 rotates and the wafer 28 mounted on the wafer stage 27 rotates.

At this time (when the shaft 24 rotates), the impeller 11 rotates at the same time, and an air flow in the direction opposite to the wafer stage 27 (the direction away from the wafer stage 27) is generated around the shaft 24 while taking in external gas from the gap 13. The flow of this air current is shown by dotted arrows in FIG. This air flow becomes a gentle laminar flow, whereby particles generated from the driving unit such as the motor 22, the belt 26, the driving pulley 23, and the driven pulley 25 are guided to the lower surface of the machine frame 21, and these are scattered from the gap 13. Thus, reaching the wafer 28 is prevented. In consideration of this action, it is preferable that the driving unit is arranged densely in the lower part of the impeller 11. Further, the upper surface and the side surface of the machine frame 21 are formed so that there is no gap other than the gap 13 so that particles are not scattered from other than the gap 13.
Then, the induced particles are discharged from the hole of the punching metal 12 provided on the lower surface of the machine casing 21. As explained above, the pre-aligner is usually placed in a locally clean housing, placed inside a clean airflow that passes through the filter and flows from heaven to the ground, and therefore from the hole in the punching metal 12. The discharged particles are directly guided to the lower part of the pre-aligner. Therefore, particles discharged from the punching metal 12 do not adhere to the wafer 28 on the wafer stage 27 again. Even if it is not in a locally clean housing, a normal semiconductor manufacturing factory is constructed so that a certain amount of clean airflow flows from heaven to the ground (downflow). The pre-aligner of the present invention can maintain the above effects. Further, it is conceivable to make an appropriate hole on the lower surface of the machine frame 21 only in a necessary portion (for example, only a portion below the impeller 11) without using the punching metal 12, but it is constant like the punching metal. When a plate with holes arranged at regular intervals is used on the lower surface of the machine frame 21, the discharged air flow is rectified by the holes of the punching metal 11 and becomes a laminar flow, so the flow of downflow in the local clean housing Is less likely to disturb the particles, and the risk of particles adhering to the wafer is also reduced.

When the wafer 28 rotates by a predetermined amount, the sensor 29 detects the position of the outer peripheral portion of the wafer 28, the amount of deviation of the center position of the wafer 28 from the reference axis, and the notch or oriental flat ( The position of the orientation flat) is detected. Information on the detected center position shift amount and notch position of the wafer 28 is transmitted to a pre-aligner control device (not shown). The pre-aligner control device processes the above-mentioned information and notifies the deviation amount to a control device of a wafer transfer device (not shown). The pre-aligner controller rotates the motor 22 and moves the notch of the wafer 28 to a predetermined position. Also at this time, the impeller 31 rotates and generates airflow in the direction opposite to the wafer mounting portion around the shaft 24, thereby preventing particles generated from the motor 22, belt 26, and other driving portions from reaching the wafer. To do.
Then, the control device of the wafer transfer device (not shown) instructs the transfer device to operate the drive mechanism of the transfer device, so that the center position of the wafer 28 coincides with the reference axis of the hand of the transfer device, and the transfer device becomes the wafer 28. Is received from the wafer stage 27. At this time, before the wafer transfer device (not shown) receives the wafer 28 from the wafer stage 27, a wafer suction device (not shown) provided so as not to shift the mounting position on the wafer stage 27, or to hold the outer periphery of the wafer. The wafer gripping means (not shown) is unlocked (not gripped). The wafer alignment operation is performed by the above means.

In some cases, the control device of the pre-aligner device and the control device of the wafer transfer device are integrally configured. In addition, when the gripping means provided on the wafer stage 27 is configured to grip the wafer 28 and simultaneously align the center position thereof, the wafer transfer device performs only the operation of transferring the wafer 28 to the pre-aligner.
Further, a pre-aligner having a structure in which a driving mechanism for correcting the deviation of the center position of the wafer 28 from the reference axis is provided inside the machine frame 21, that is, the wafer conveyance device (wafer handling robot) corrects the deviation. However, even if it is a pre-aligner having a mechanism for driving and correcting the wafer stage 27 and the shaft 24 in the horizontal plane direction, the impeller 31 that rotates in synchronization with the shaft 24 may be provided.

As described above, according to the pre-aligner of the present invention, when the impeller is attached to the rotation shaft (shaft) to which the wafer stage is attached and the wafer stage is rotated, the impeller is also rotated in synchronization with the rotation shaft. Since the surrounding air is configured to flow in the opposite direction to the wafer, there is an effect that particles generated from the drive mechanism of the rotating shaft are not attached to the wafer. Further, since the particles are discharged to the lower surface of the pre-aligner using the punching metal, the particles can be discharged without disturbing the downflow in the local clean.
Further, even with a pre-aligner having means for moving the wafer in the horizontal plane direction, the present invention can be easily applied to prevent particles.

Side sectional view showing a drive mechanism of a pre-aligner embodying the present invention Side sectional view showing a conventional pre-aligner drive mechanism FIG. 2 is a side sectional view showing a drive mechanism in which particle scattering prevention means is provided in the drive mechanism of FIG. FIG. 2 is a side sectional view showing a drive mechanism in which particle scattering prevention means is provided in the drive mechanism of FIG.

Explanation of symbols

11: Impeller 12: Punching metal 13: Gap 21: Pre-aligner frame 22: Drive motor 23: Drive pulley 24: Shaft 25: Driven pulley 26: Timing belt 27: Wafer stage 28: Wafer 29: Sensor 30: Fan 41: Magnetic fluid seal

Claims (7)

A wafer stage on which a semiconductor wafer is mounted; a drive unit that rotates the wafer stage; a machine frame that houses the drive unit; and a sensor that detects an outer peripheral portion of the semiconductor wafer rotated by the drive unit. In the pre-aligner device for rotating the semiconductor wafer to a desired position according to the information of the outer peripheral portion detected by the sensor,
One end connected to the wafer stage, the other end connected to the drive unit, and a shaft rotatably supported on the upper plate of the machine frame, and an impeller provided on the shaft inside the machine frame With
The pre-aligner apparatus, wherein the impeller is provided so that an airflow is generated in a direction away from the wafer stage when the shaft is rotated by the driving unit.   The impeller is provided on the shaft so as to be positioned between the drive plate and a position directly below the gap between the upper plate of the machine frame and the shaft, and when the shaft is rotated by the drive portion, the gap 2. The pre-aligner according to claim 1, wherein the pre-aligner is provided so as to generate the airflow toward a lower portion inside the machine frame while taking in the gas in the upper part of the upper plate from the top.   The drive unit includes: a motor fixed to the machine casing; a drive pulley provided on a rotation shaft of the motor; a driven pulley connected to the other end of the shaft; and the drive pulley and the driven pulley. 2. The wound belt, wherein the impeller is at least above the driven pulley and has a rotation diameter equal to or greater than the diameter of the passive pulley. The pre-aligner according to 2.   2. The pre-aligner device according to claim 1, wherein at least a portion of the lower surface of the machine casing corresponding to the lower side of the shaft is made of a punching metal capable of discharging the airflow.   The machine frame is configured such that side surfaces of the upper plate and the machine frame are hermetically sealed, except for a gap at a location where the shaft is rotatably supported on the upper plate of the machine frame. The pre-aligner apparatus according to 1. A pre-aligner device according to claim 1;
A robot for transporting the semiconductor wafer;
A wafer comprising: a local clean housing that accommodates the robot and the pre-aligner device and is provided with a filter on an upper portion thereof to allow a clean airflow to flow down to the robot and the pre-aligner device. Conveying system.   A semiconductor manufacturing apparatus comprising the wafer transfer system according to claim 6.

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