JPH11254359A - Member conveyance system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify re-teaching work after re-assembly of a cluster tool and repair of an arm robot and detect operation failure automatically. SOLUTION: This conveyance system is provided with a pair of optical sensors 20 (20a, 20b), 21 (21a, 21b) respectively on the top and bottom and both sides of respective cassette module chambers 13a, 13b, whose optical axes intersect at right angles at a reference point inside the chamber. A member gripping part 17 is formed with a plate of almost the same thickness as the optical axis diameter of the optical sensor 21 (21a, 21b), and a reference position gauging hole 23 is formed at the roughly central position on the top and bottom, whose central point serves as an arm reference point 24. When the point meets a chamber reference point 22, the conditions detected by both optical sensors 20, 21 are read by a computing controller connected to them to recognize that both reference points meet each other. The computing controller computes the location of the arm reference point 24 from an encoder connected to respective driving motors of a robot, and compare with the position of the chamber reference point 22 before variation, thereby detecting an error in the chamber position or operation failure of a robot.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a member transfer system in which a processing member is carried in and out of a chamber by an arm robot in a process of manufacturing a semiconductor wafer or a liquid crystal plate using a cluster tool.

[0002]

2. Description of the Related Art Conventionally, the most common method of forming a circuit in a semiconductor chip manufacturing process is a method of repeatedly performing various processes such as film formation, etching, and impurity diffusion on the surface of a circular flat semiconductor wafer. .

FIG. 5 is a top view of an example of a cluster tool 1 used as an apparatus for performing the above-described wafer surface treatment. In this figure, process chambers 2a to 2d which are partition rooms (hereinafter referred to as chambers) for performing each wafer processing, and two cassette modules for transferring a wafer before processing and a wafer after processing to outside of the cluster tool 1, respectively. Chambers 3a and 3b are installed so as to surround a transfer chamber 5 in which a transfer arm robot 4 is installed at the center.

Here, in the transfer chamber 5 (transfer area) in the cluster tool 1 and the work areas such as the process chambers 2a to 2d, a vacuum state is set for the purpose of preventing contamination (deterioration) of the wafer surface by gas and preventing dust. And
It has a closed structure that is isolated from the outside air. For this reason, the cassette module chambers 3a and 3b for transferring wafers to and from the outside of the cluster tool 1 are set with two gate valves 6a, 6b, 6c and 6d, which are airtight opening and closing mechanisms.

[0005] The transfer arm robot 4 moves in the R direction (for example, arrow R in the figure, which is an expansion and contraction operation of feeding and retracting the inside of each of the process chambers 2a to 2d surrounding the arm robot 4). All the other radial directions are included.), A Z-direction movement (not shown), which is a vertical movement of lifting and placing the semiconductor wafer in each of the chambers 2a to 2d, and a movement between the chambers 2a to 2d. The member gripper 7 at the tip of the arm 9 is moved to an arbitrary position by carrying out a combination of movements in three coordinate directions of a θ-axis rotational movement (arrow θ in the drawing), which is a plane rotational movement for movement, and transports the semiconductor wafer 8. It is possible to do.

Then, the member gripper 7 at the tip of the arm 9 is reached into each of the process chambers 2a to 2d surrounding the periphery of the transfer arm robot 4, and before and after the processing by the up / down operation and the feeding / retracting operation. (Pick-up and place) operation of the semiconductor wafer 8 described above. In addition, the cluster tool 1 having the above configuration can be used for other manufacturing processes other than the semiconductor wafer 8 such as a liquid crystal plate by replacing the member gripping portion 7 at the tip of the arm 9 with an appropriate shape.

A drive motor for driving and controlling the movement of the arm robot 4 in each direction can be controlled with a rotation angle accuracy of, for example, 360 ° / 8192. Further, by using an encoder, the rotational position of each drive motor at that time can be determined. This enables self-detection.

Then, by calculating based on the rotational position of each drive motor, the arm 9 in the cluster tool 1 is operated.
(When the zero point is set in the cluster tool 1 at the initial stage of assembly), and thus the relative movement amount of the arm 9 can be detected.

By utilizing the above-described detection unit, calculation unit, and data storage unit, the movement of the arm 9 is actually performed by an artificial operation at the time of initial setting at the time of assembling the cluster tool 1, thereby enabling each process to be performed. Chamber 2
The coordinates of the moving points or the moving amounts between successive points and the moving order between the moving points a to d and the cassette module chambers 3a and 3b or between the process chambers 2a to d and the cassette module chambers 3a and 3b are stored. This operation is called a teaching operation (teaching). (The movement point taught in the following is referred to as a teaching point.) This teaching operation is performed on the transfer arm robot 4 installed in the working area in the cluster tool 1 in a vacuum state as described above. The method is performed by remote control using a remote controller or the like while visually confirming the operation. The teaching work requires a large number of points and a large number of operation steps, and requires high-precision teaching, requiring considerable labor.

[0010]

Conventionally, when a hand or a robot itself is replaced due to damage in a semiconductor transfer device, a teaching operation has to be performed again in order to reset a teaching point.

Further, since the robot or the like is carried out in a detached state at the time of shipment from the factory, an error (deviation) occurs in the position of the teaching point stored up to that time due to the high-precision teaching work at the time of carrying in and reassembling. Therefore, it was necessary to redo the teaching work to correct the error. Further, even if the arm robot is repaired or parts are replaced during operation, an error in the teaching point occurs, so that the teaching operation has to be performed again each time. From the beginning, the above re-teaching operation teaches all the teaching points at once, each time requiring a great deal of labor and time.

Since high precision is required for the operation of the transfer arm, it is important to detect the operation abnormality of the mechanical part including the arm drive mechanism with high precision. There is no other way but to determine the abnormality, and it has been difficult to detect an operation error caused by slight deformation or wear due to aging.

Further, when the drive shaft of the robot penetrates the partition wall of the chamber, the position of the arm may change depending on the vacuum or the atmospheric pressure in the chamber. May not be usable.

In view of the above problems, the present invention makes it possible to simplify the re-teaching operation after repairing / replacing parts of an arm robot, and further, it is possible to carry out these operations from a position separated by a vacuum partition. It is another object of the present invention to provide a member transfer system that enables automatic detection of an operation error of an arm robot with high accuracy.

[0015]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems, and is constituted as follows. First, the present invention is applied to a member transfer system in which a processing member is transferred between chambers installed around a transfer area by an arm robot in a cluster tool used in a manufacturing process of a semiconductor wafer or a liquid crystal plate or the like.

The present invention provides an arm reference point set on the arm of the arm robot, arm reference point position measuring means for measuring the position of the arm reference point in a coordinate system on which the arm robot operates, and an arm reference point. A reference point coincidence detecting means for detecting that the point coincides with a chamber reference point set in the chamber; and an arm reference point position measuring means when the chamber reference point coincides with the arm reference point. A calculation control unit that controls the arm robot based on the coordinate position of the arm reference point.

Thus, a teaching point error occurring before and after reassembly of the cluster tool or before and after repair and replacement of parts of the arm robot is detected at the time when two reference points physically match in each chamber. Since the calculation can be performed using the change difference value of the arm reference point position, it is possible to automatically correct all the teaching points collectively, and further, the change difference value of the arm reference point position is periodically detected during normal operation. By doing so, it is possible to easily and accurately check the operation abnormality of the arm robot.

Further, for example, as described in claim 2, the control of the arm robot performed by the arithmetic and control unit is configured to correct a position error of the chamber reference point at the time of readjustment. As a result, it is possible to easily and simply correct the errors of a large number of teaching point positions generated in the above-described chamber units for all the teaching points.

Further, for example, as described in claim 3, the control of the arm robot performed by the arithmetic control unit is configured to detect an abnormal state during normal operation.
This makes it possible to easily and accurately diagnose the operation abnormality during the normal operation described above.

Further, for example, the arm reference point position measuring means includes an encoder for detecting a rotational position of a drive motor of the arm, and a coordinate system of the arm reference point based on an output signal of the encoder. And a calculation unit for calculating the position in. As a result, it is possible to detect by high-precision and high-speed electrical processing while being able to be configured with a small number of components.

Further, the reference point coincidence detecting means is provided in a vertical direction of the chamber and detects a horizontal coincidence between the arm reference point and the chamber reference point. And vertical position detecting means installed on the side of the chamber for detecting a vertical coincidence between the arm reference point and the chamber reference point. As a result, it is possible to detect by high-precision and high-speed optical processing while being able to specifically configure with a small number of components.

Further, for example, a reference point horizontal position measurement hole penetrating in the vertical direction so as to pass through the arm reference point is formed in the arm, and the horizontal position detection means measures the reference point horizontal position. The arm is constituted by a flat plate located on the same horizontal plane as the arm reference point, and the reference point vertical position detecting means detects that the arm is located at the same height. It consists of an optical sensor. Thereby, a member presence / absence detection sensor for detecting the number of members placed on the member placement cassettes conventionally installed in each cassette module chamber of the cluster tool, and a member flyout detection for detecting the protrusion of the placement from the cassette Since it can be configured using sensors, there is no need to provide two new sensors, and there is a specific means that can recognize the spatial coincidence between the arm reference point and the chamber reference point with high accuracy and high speed with a simple configuration. realizable.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is a top view of an example of a cluster tool 11 provided with a member transport system according to the present invention.

In this figure, a member transfer arm robot 14 is installed at the center of a transfer chamber 15 having a hexagonal shape. Around the transfer chamber 15, in particular, in the upper four sides in the figure, a process chamber
Gate valves 2a to 2d are provided on two lower sides in the figure, and cassette module chambers 13a and 13b for carrying processing members in and out of the cluster tool 11 are gate valves 16a and 16b which are airtight opening and closing mechanisms. The arm robot 14 is installed so as to radially surround the transfer chamber 15 and the arm robot 14 installed at the center thereof.

The cassette module chamber 13a,
In b, similar gate valves 16c and 16d are installed outside the cluster tool 11. Next, FIG. 2 shows one cassette module chamber 13 in the configuration of the present invention.
FIG. 4 is a perspective view showing a state in which an arm 19 of the arm robot 14 enters the inside of a and b, with a part of cassette module chambers 13a and 13b having a substantially rectangular parallelepiped shape omitted.

Then, the cassette module chamber 13
The optical sensors (upper and lower surfaces 20a) each including a pair of a light emitter and a light receiver on opposite sides and upper and lower surfaces of the arms 19a and 19b with respect to the arm 19 intrusion direction (arrow A in the figure).
a, 20b and side surfaces 21a, 21b).
An optical axis formed by a pair of optical sensors facing each other is installed so as to be perpendicular to both surfaces to which they are attached.

The plane including the horizontal optical axis intersects the upper and lower optical axes. And cassette module chambers 13a, b
All the teaching points set as the movement target points of the arm 19 therein are set at the intersection points as absolute reference points (hereinafter referred to as chamber reference points 22). And this 2
The paired optical sensors 20a, b, 21a, b are connected to an arithmetic and control unit 28 (see FIG. 3) composed of a computer or the like, and detect the passage or blocking of the optical axis of each of the optical sensors 20a, b, 21a, b. I do.

In the construction of the one arm 19, the transport member 1
The member gripper 17 for directly transporting the cassette 8 includes an optical sensor 21 installed on the side of the cassette module chambers 13a and 13b.
A reference position measuring hole formed of a flat plate having a thickness substantially matching the diameter of the optical axes a and b and serving as a reference point for detecting the position of the member holding portion 17 at a substantially central position of the entire member holding portion 17. 2
A hole 3 having a diameter substantially the same as the optical axis of the optical sensors 20a and 20b is formed through the upper and lower surfaces of the flat plate. That is, one point at an intermediate position between the upper and lower surfaces of the flat plate on the central axis of the reference position measurement hole 23 is a position reference point of the member gripper 17 (hereinafter referred to as an arm reference point 24).
). Each chamber 12a-d and 13a, b
The teaching points set inside are all arm reference points 2
4 is set as the movement target point.

FIG. 3 is a block diagram of a member transport system according to the present invention. In this figure, drive motors 26 _R , 26 for driving respective joints corresponding to respective coordinates R, θ, Z are shown.
encoders 27 _R connected to θ and 26 _Z respectively, 2
7θ, 27 _Z rotation movement amount is outputted by, is input to the arithmetic and control unit 28 which further output is described above, the drive motors 26 _R, theta, the rotational position of the _Z, the arm reference point 24 in turn conveying areas The position is calculated by R,
It is detected by three coordinate values of θ and Z.

The operation of the member transport system according to the present invention will be described below. The principle of the position correction function of the present invention is as follows.
Within d and 13a and 13b, the relative position relationship between the teaching points (including the chamber reference point 22) does not change, and the transfer arm robot 14 and the transfer arm robot 14 whose installation positions have changed due to replacement or repair of parts. Process chambers 12a-d
It is assumed that the error is caused by a change in the relative positional relationship between the cassette modules or between the cassette module chambers 13a and 13b.

Under the premise of this error, the error that occurs after the repair or replacement of the parts of the arm robot 14 is caused in all the teaching points inside the chambers 12a to 12d, 13a and 13b in the R direction, around the θ axis, and in the Z direction. (Vertical direction) coordinate components occur in the same amount. That is, each chamber 12a-
The errors of the teaching points in d, 13a, and b are all the same, and an error applicable to all the teaching points can be obtained by detecting only an error of one of the chamber reference points 22 as a position reference point of the teaching points as a sample value. It has been detected.

By using this error for position correction, it is not necessary to re-teach all the teaching points in the cluster tool 11 and it is necessary to perform the teaching once only.
Error correction of most teaching points within 1 is possible.

Here, the error detection process will be described with reference to the flowchart of FIG. First, the arm 19 is moved so that the arm reference point 24 and the chamber reference point 22 coincide with each other by manual remote control using a remote controller or the like as in the teaching operation at the time of the initial assembly (S1). At the time of the operation of matching these two reference points, first, the error between the two reference points is usually only in millimeters.
By using colored light such as red for the optical axes of 0a, b, 21a, and b, the corresponding positions of the optical axes on the arm 19 can be visually checked, and the two position reference points can be easily matched. It becomes possible.

The operation of matching the common points can be performed by an automatic sequence in which the operation of the robot arm and the detection of the optical sensor output are combined. Here, when the two position reference points coincide with each other, the optical sensors 21a and 21b installed horizontally on the side surfaces inside the cassette module chambers 13a and 13b are turned off because the optical axis is shielded by the thickness of the member holding portion 17. Then, the optical sensors 20a and 20b vertically installed on the upper and lower surfaces inside the cassette module chambers 13a and 13b pass through the reference position measuring holes 23 which are vertically drilled in the flat plate of the member holding portion 17 (S2). It is turned on (S3). Thus, both sensors 20a, b, 21a, b
When the conditions (1) and (2) match, the arithmetic and control unit 28 recognizes that the two position reference points match with high accuracy (S4).

As an operation to match the reference point with high precision, for example, the robot arm is finely moved in the R, θ, and Z directions, and in each axis operation, light transmission from the optical axis to light blocking or light blocking to light transmission is performed. The change point is regarded as an edge, and the midpoint of each edge is obtained.

In this coincidence state, the arithmetic and control unit 28 controls the encoder 2 installed on the arm robot 14.
7 _R, theta, a drive motor 26 for driving each joint of the arm robot 14 from the output of the _{Z R,} theta, to detect the rotational position of the _Z (S5), the arithmetic and control unit 28 is a new position of the arm base point 24 It is calculated as the chamber reference point P ₁ (R ₁ , θ ₁ , Z ₁ ) (S6). Then, the difference value from the position P ₀ (R ₀ , θ ₀ , Z ₀ ) of the chamber reference point, which was stored before being changed by repair / part replacement or reassembly, dP
(DR, dθ, dZ) [dR = R ₁ −R ₀ , dθ = θ ₁
−θ ₀ , dZ = Z ₁ −Z ₀ ] is a correction value that can be used when the teaching point is reset (S7).

In the resetting work accompanying the repair or replacement of parts of the arm robot 14, all the chambers 12a to 12a
Since the relative positional relationship between d, 13a, and b has not changed, the position error of the arm robot 14 itself with respect to the entire cluster tool 11 can be detected only by detecting an error in only one chamber.

On the other hand, it is also possible to diagnose the abnormality of the mechanical part of the arm robot 14 by performing the above-described correction value detection work periodically during normal operation and detecting a large change in dP. Further, the data relating to the magnitude and the change process of the dP can also be used as reference materials for estimating and diagnosing an abnormal part.

In this case, the operation of matching the two reference positions is as follows.
By incorporating and executing the automatic sequence, an effective diagnostic method is provided. When the transfer arm robot 14 operates two or more arms, for example, a dual arm type, the reference position adjustment work for detecting the correction value and performing the abnormality diagnosis needs to be performed for each arm. There is.

Each cassette module chamber 13
Two pairs of optical sensors 20a, b, 21 installed inside a, b
The components a and b can be configured by using (shared) a member presence / absence detection sensor and a member protrusion sensor installed in each cassette module chamber 3a, b of the conventional cluster tool 1.

Here, the member presence / absence detection sensors are provided on both sides of each cassette module chamber 13a, b so as to detect the number of members placed on the member placement cassettes installed in each cassette module chamber 13a, b of the cluster tool 11. The member ejection sensors are installed on the upper and lower surfaces of each of the cassette module chambers 13a and 13b so as to detect the ejection of the attachment from the member attachment cassette. Since the optical axis is emitted and the passage / interception is detected, it can be used also as the detecting means of the arm reference point 24 in the present invention, and thereby the overall configuration of each of the cassette module chambers 13a and 13b is reduced. Simplification can be achieved.

Each of the chambers 12a-d and 13a, b
The set position of the chamber reference point 22 set inside and the set position of the arm reference point 24 set on the arm 19 need not be limited to substantially the center as described above. If they can be matched, they can be set at other positions. For example, the arm reference point 24 is set on the left side of the tip of the member
May be set to the lower left side inside the chambers 12a to 12d and 13a and 13b.

As a means for detecting the position of the arm reference point 24, other than detecting the passage / blocking of the optical axis, it is also possible to detect the reflection on the flat surface of the member holding portion 17. In this case, instead of drilling the reference position measurement hole 23 at the same horizontal plane position as the arm reference point 24 on the member holding part 17, a mirror for reflecting the optical axis is attached with a diameter substantially equal to the optical axis. Reference point 24 and chamber reference point 22
In order to sufficiently receive the light reflected by the mirror in a state where the horizontal positions of the mirrors coincide with each other, a light-emitting device and a light-receiving device, which are a set of optical sensors, are provided in a chamber facing the mirror mounting surface on the flat plate of the member holding portion 17. It becomes the structure juxtaposed on the inner surface. According to this configuration, the detection reaction of the optical sensor is indicated only at the position (mirror) of the arm reference point 24 on the flat plate of the member holding portion 17, and it is possible to prevent an erroneous reaction such as when the optical axis passes out of the outer contour of the arm 19. . In addition, this configuration can be applied to the side surface of the chamber for detecting the height position of the arm reference point 24 when the member gripper 17 has a sufficient thickness in the vertical direction.

The sensor used as the means for detecting the position of the arm reference point 24 is not limited to the above-mentioned optical sensor. For example, a microprojection formed on the arm 19 and a microswitch provided inside each of the cassette module chambers 13a and 13b can be used. It is also possible to configure with.

In addition, a magnetic sensor or the like can be applied. or,
The present invention is applicable not only to the cluster tool but also to other devices using an arm robot. Of course, it is not limited to transportation,
For example, it may be applied to a processing robot or the like.

It is not always necessary to use a sensor for detecting a conventional cassette, and a sensor may be provided separately.
The sensor is not limited to the cassette module chamber, and may be provided in, for example, a process chamber. Alternatively, it may be provided in the member transfer chamber.

The detection direction of the sensor is up and down as in the embodiment,
The direction is not limited to the horizontal direction, and may be another direction. However, it is necessary to be perpendicular and parallel to the robot's arm expansion and contraction surface.

The expansion and contraction surface of the arm is not limited to a horizontal plane, but may be changed as appropriate depending on the application. In that case, the installation position of the sensor,
Alternatively, the detection direction is changed accordingly. The number of chambers for both the process and the cassette module is not limited to the embodiment but can be changed as appropriate. In that case, of course, the shape of the member transfer chamber is not hexagonal.

The location where the sensor is provided is not limited to a single chamber, but may be provided at a plurality of locations.

[0050]

As described above, according to the present invention, in a cluster tool used in a manufacturing process of a semiconductor wafer or a liquid crystal plate, a member transfer system for transferring a processing member between chambers by an arm robot is provided. The repair and replacement of parts cause errors in the positional relationship between the parts, so it is necessary to re-teach all of the many arm teaching points. Can be corrected, and the simplicity of handling of the cluster tool is greatly improved.

Further, it is possible to diagnose the operation abnormality of the mechanical part of the arm robot with high accuracy by periodically detecting the position error in the chamber unit during the normal operation. Therefore, it is possible to improve the operation efficiency and, consequently, the production efficiency by quickly responding to the failure of the cluster tool.

[Brief description of the drawings]

FIG. 1 is a top view of an example of a cluster tool according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state where an arm is about to reach the inside of a cassette module chamber of the cluster tool according to the embodiment of the present invention, with a part of the chamber omitted;

FIG. 3 is a block diagram of a member transport system of the present invention.

FIG. 4 is a flowchart illustrating an error detection process of an arm reference point position according to the present invention.

FIG. 5 is a top view showing an example of a conventionally used cluster tool.

[Explanation of symbols]

Reference Signs List 11 cluster tool 12a, b, c, d process chamber 13a, b cassette module chamber 14 transfer arm robot 15 transfer chamber 16a, b, c, d gate valve 17 member gripper 18 transfer member (semiconductor wafer) 19 (arm robot ) Arm 20 a, b Vertical light sensor 21 a, b Left / right light sensor 22 Chamber reference point 23 Reference position measurement hole 24 Arm reference point 25 Arm robot revolution axis 26 _R , θ, _Z drive motor 27 _R , θ, _Z encoder 28 Arithmetic control unit A Arm entry direction in chamber

Claims (6)

[Claims] 1. A member transfer system for carrying a processing member into and out of a chamber installed around the member by an arm robot. An arm reference point set on an arm of the arm robot and a coordinate system operated by the arm robot Arm reference point position measuring means for measuring the position of the arm reference point, reference point coincidence detecting means for detecting that the arm reference point matches a chamber reference point set in the chamber, and the chamber reference A calculation control unit for controlling the arm robot based on the coordinate position of the arm reference point obtained by the arm reference point position measuring means when the point and the arm reference point coincide with each other. Transport system. 2. The member transport system according to claim 1, wherein the control of the arm robot performed by the arithmetic and control unit is a correction of a position error of the chamber reference point at the time of readjustment. 3. The member transport system according to claim 1, wherein the control of the arm robot performed by the arithmetic and control unit is detection of an abnormal state during normal operation. 4. The arm reference point position measuring means includes an encoder for detecting a rotation position of a drive motor of the arm, and a calculation unit for calculating a position of the arm reference point based on an output signal of the encoder. The member conveying system according to any one of claims 1 to 3, wherein the member conveying system is performed. 5. The reference point coincidence detecting means is provided in a vertical direction of the chamber, and detects horizontal position coincidence between the arm reference point and the chamber reference point. 4. The member conveying system according to claim 1, further comprising a vertical position detecting unit installed in the first position detecting unit to detect a vertical coincidence between the arm reference point and the chamber reference point. 6. A reference point horizontal position measurement hole penetrating in the vertical direction so as to pass through the arm reference point is drilled in the arm, and the horizontal position detecting means detects the reference point horizontal position measurement hole with an optical sensor. The arm is constituted by a flat plate located on the same horizontal plane as the arm reference point, and the vertical position detecting means is constituted by an optical sensor for detecting that the arm is located at the same height. The member conveying system according to claim 5, wherein: