JP4182765B2 - Robot automatic teaching apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic teaching apparatus and method for transferring a substrate such as a semiconductor wafer by a robot.
[0002]
[Prior art]
Japanese Unexamined Patent Application Publication No. 11-254359 is disclosed as a conventional example for the purpose of simplifying re-teaching work after repair of an arm robot. FIG. 6 is a perspective view showing a state where a sensor and a robot arm built in a cassette module chamber of a conventional example are about to reach.
In FIG. 6, a pair of optical sensors 200a, 200b and 201a, 201b are installed on the upper and lower surfaces and both side surfaces of the cassette module chamber 100, respectively, and their optical axes are orthogonal to each other at a reference point 202 inside the chamber. The member gripping portion 101 of the robot arm 102 is formed of a flat plate having a thickness substantially the same as the optical axis diameter of the optical sensors 201a and 201b, and a reference position measuring hole 203 is vertically drilled at a substantially central position. Becomes the arm reference point 204. When the arm reference point 204 coincides with the chamber reference point 202, the detection state of the two optical sensors 200 and 201 connected to the arithmetic and control unit (not shown) is read to recognize the coincidence of the reference points 202 and 204. .
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-254359
[Problems to be solved by the invention]
However, this conventional example has a problem that it is difficult to obtain the mounting accuracy of the optical sensors 200 and 201 and the detection accuracy of the optical sensors 200 and 201 is poor. Moreover, it is necessary to process the cassette module chamber 100 and the robot arm 102, and there is a problem that there is a restriction in the design thereof.
Accordingly, a first object of the present invention is to provide an automatic robot teaching apparatus capable of teaching a reference position in three dimensions with high accuracy.
Another object of the present invention is to provide an automatic robot teaching method in which re-teaching is greatly simplified by automatically detecting a certain reference position at the time of robot arm re-teaching.
[0005]
[Means for Solving the Problems]
In order to achieve the first object, a first invention of the present application is an automatic teaching apparatus for a robot that transports a substrate to a semiconductor manufacturing apparatus by a robot arm, which is substantially the same shape as the substrate to be transported, and is in the X direction. And a dummy substrate provided with slits separated in two dimensions in the Y direction at predetermined positions, an X direction detection sensor for outputting position signals corresponding to the X direction slit and the Y direction slit on the dummy substrate, and the Y direction A sensor board provided with a detection sensor and a Z direction detection sensor that outputs a position signal in the Z direction that is perpendicular to the two dimensions in the X and Y directions, and each of the detection sensors in the X, Y, and Z directions And a signal processing device that outputs an absolute position signal from the detected signal.
In the first aspect of the present invention, the reference position in the X, Y, and Z directions can be accurately obtained simply by placing the sensor board at the reference position and bringing the robot arm holding the dummy substrate to a predetermined position on the sensor board. It can be detected.
[0006]
According to a second invention of the present application for achieving the second object, in a robot automatic teaching method for transporting a substrate to a semiconductor manufacturing apparatus by a robot arm, the substrate is substantially the same shape as the substrate to be transported, and is in the X direction. And a dummy substrate provided with slits separated in two dimensions in the Y direction at predetermined positions, an X direction detection sensor for outputting position signals corresponding to the X direction slit and the Y direction slit on the dummy substrate, and the Y direction A sensor board provided with a detection sensor and a Z direction detection sensor that outputs a position signal in the Z direction that is perpendicular to the two dimensions of the X and Y directions, and each of the detection sensors in the X, Y, and Z directions A signal processing device that outputs an absolute position signal from the detection signal of the sensor, the sensor board is disposed at a reference position, and the dummy substrate is mounted on the robot arm. The dummy board is moved to a position where the 3D position can be detected facing the sensor board, the robot arm is taught using one point of the 3D position signal as a reference position, and re-teaching is performed. At this time, the dummy substrate is mounted on the hand of the robot arm, the dummy substrate is moved to a position where the three-dimensional position can be detected facing the sensor board, and the taught one reference position is automatically set. It is an automatic teaching method of a robot characterized by detecting automatically.
In the second aspect of the invention, by teaching one point as the reference position, the reference position at the time of re-teaching can be automatically detected.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram showing an embodiment of the present invention. In FIG. 1, 10 is a sensor board provided with sensors for outputting position detection signals in the X direction, Y direction, and Z direction, 20 is a dummy substrate provided with X direction and Y direction detection slits, 30 is an X direction, A sensor signal processing apparatus that receives output signals from the respective sensors in the Y and Z directions and detects a three-dimensional absolute position signal, 40 is a transfer robot that transfers a substrate such as a wafer, 41 is a robot arm, and 42 is a wafer. Forks for mounting substrates such as 43, cassettes for storing substrates such as wafers, 44 pre-alignment devices for detecting the center of gravity, notches, orientation flats of wafers, etc. 50 for robot control devices, 51 for managing system operations The host CPU 52 is an operating device for manually inputting the robot operation.
[0008]
FIG. 2A illustrates the sensor board 10 in detail. In FIG. 2A, 11 is an X direction detection sensor, 12 is a Y direction detection sensor, and 13 is a Z direction detection sensor. The X direction detection sensor 11 and the Y direction detection sensor 12 may be analog output signals of A phase and B phase that are 90 ° out of phase, and the detection method may be optical or magnetic. The Z direction detection sensor 13 may be an analog output or a digital output, but in this embodiment, a light reflection type analog output sensor is used.
FIG. 2B illustrates the dummy substrate 20 in detail. In FIG. 2B, 21 is an X direction detection slit, and 22 is a Y direction detection slit. In the case of the optical type, the X direction detection slit 21 and the Y direction detection slit 22 are formed by depositing a material having a high reflectance such as aluminum deposition. In the case of a magnetic type, a slit formed by magnetizing a magnet in a slit shape or a magnetic steel plate by machining or etching may be used. The X-direction and Y-direction detection slits 21 and 22 can detect a two-dimensional absolute position by forming approximately one period. By setting the outer size of the dummy substrate 20 to be the same size as the substrate to be transferred, it becomes easy to match the central axis of the substrate to be transferred with the central axis of the dummy substrate 20.
[0009]
The positional relationship between the X direction and Y direction detection sensors 11 and 12 provided on the sensor board 10 and the X direction and Y direction detection slits 21 and 22 provided on the dummy substrate 20 is determined by mounting the substrate on the fork 42. reference position O ₁ from the X-direction detecting sensor position A1 of the sensor board 10 to the substrate central axis 60 when (X1, Y1), Y-direction detecting sensor position A2 (X2, Y2), and the reference position O of the dummy substrate 20 ₂ from X-direction detection slit position A1 ′ (X1 ′, Y1 ′) and Y-direction detection slit position A2 ′ (X2 ′, Y2 ′) are positioned so that A1 = A1 ′ and A2 = A2 ′. Set. The Z direction detection sensor position is not specified for the X and Y directions. For the Z direction, the distance from the predetermined slits of the X direction and Y direction detection sensors 11 and 12 is the detection range of the Z direction detection sensor. To be.
[0010]
FIG. 3 is a diagram for explaining the signal processing of the sensor signal processing device 30 for the output signals from the X direction, Y direction, and Z direction detection sensors. In FIG. 3, A and B phase output signals from the X direction detection sensor 11 are amplified by amplifiers 31a and 31b, converted into digital signals by an A / D converter 32a, and converted into absolute values by an absolute value signal generation processor 33. The Similarly, the A and B phase output signals from the Y direction detection sensor 12 are amplified by the amplifiers 31c and 31d, converted into a digital signal by the A / D converter 32b, and converted into an absolute value by the absolute value signal generation processor 33. The output signal from the Z direction detection sensor 13 is converted into a digital signal by the A / D converter 32 c and converted into an absolute value by the absolute value signal generation processor 33.
[0011]
The principle of generating an absolute position based on sensor outputs from the X direction and Y direction detection sensors 11 and 12 will be described with reference to FIG. Since the X and Y directions are based on the same principle, only the X direction will be described. The output signal from the X direction detection sensor 11 is configured to output a B phase signal, which is a substantially sine wave signal that is 90 degrees out of phase with the A phase, which is a substantially sine wave signal, for only one cycle. The relationship between the A-phase and B-phase sensor output voltages V _a and V _b and the position X is expressed by the following equation.
V _a = sinX
V _b = cosX
From these output signals, the position X can be obtained using the following equation.
X = tan ⁻¹ (V _a / V _b )
[0012]
Since each detection sensor outputs only a signal for one period of the slit, an absolute position within one period of the slit is output. Further, the slits are arranged for several cycles, and a sensor capable of detecting the number of slits among the number of slits is arranged outside, and the absolute position and the number of the slit within one cycle of the slit are arranged. The absolute position for several slit periods may be detected by combining signals that detect whether a slit is detected. Since the resolution of the absolute position is determined by the number of divisions of the A / D converter 32, a high-resolution absolute position signal can be obtained by increasing the number of divisions of the A / D converter 32.
Next, a method for teaching the robot arm using the sensor board 10 and the dummy substrate 20 will be described. FIG. 5 shows a flowchart of the teaching method.
[0013]
The first teaching method will be described below.
Step S100: The sensor board 10 is arranged at a predetermined position.
Step S110: The center position of the dummy substrate 20 is measured by the pre-alignment device 44. If the center position of the substrate is always determined when the substrate is mounted on the fork 42, this operation is not necessary.
Step S120: The dummy substrate 20 is mounted on the fork 42. At this time, the dummy substrate 20 and the substrate that is normally transported are mounted so that the center positions thereof are the same.
Step S130: The fork 42 is moved using the operating device 52 so that the dummy substrate 20 and the sensor board 10 face each other, and is moved to a range where a three-dimensional position can be detected.
Step S140: The Z direction is moved so that the distance between the dummy board 20 and the sensor board 10 determined in advance by the Z direction detection sensor 13 is the same.
Step S150: XY direction absolute position is detected.
Step S160: It is determined whether or not it is re-teaching. Here, since it is the first, the process proceeds to step S170.
Step S170: A point having the detected three-dimensional position is set as a teaching reference point, and this reference point is stored in the host CPU 51.
Step S180: Teaching the robot arm using the operating device 52 with the reference point as the reference position.
Step S190: The teaching point is stored in the host CPU.
Step S200: End of the first teaching.
[0014]
Further, the re-teaching method will be described.
Steps S100 to S150 are the same as the first teaching method. However, since the determination in step S160 is re-teaching, the process proceeds to step S210.
Step S210: The difference between the reference point stored in advance in the host CPU 51 and the current position is obtained.
Step S220: End of re-teaching.
Since the deviation from the reference point can be grasped from the obtained difference, all the points taught first are known, and thus the re-teaching is completed.
With the configuration and means described above, when teaching the robot arm, the reference point can be determined by the three-dimensional position, so that the re-teaching can be simplified.
[0015]
【The invention's effect】
As described above, according to the present invention, the reference position in the X, Y, and Z directions can be obtained simply by placing the sensor board at the reference position and bringing the robot arm holding the dummy substrate to a predetermined position on the sensor board. Can be detected with high accuracy. As a result, there is an effect that the robot arm is not required to be processed and the design of the robot arm is not restricted.
In addition, by teaching one point as a reference position at the time of initial teaching, a dummy substrate can be placed within the three-dimensional position detection range including the initial teaching reference position at the time of re-teaching by replacing the robot. Since it is only necessary to move the mounted robot arm, the re-teaching time can be greatly reduced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of the present invention.
2A is a detailed view of a sensor board according to an embodiment of the present invention, and FIG. 2B is a detailed view of a dummy substrate according to the embodiment of the present invention.
FIG. 3 is a block diagram of the sensor signal processing apparatus according to the embodiment of the present invention.
FIG. 4 is a diagram showing a sensor output signal waveform according to the embodiment of the present invention.
FIG. 5 is a flowchart of a robot arm teaching method according to an embodiment of the present invention.
FIG. 6 is a perspective view of a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Sensor board 11 X direction detection sensor 12 Y direction detection sensor 13 Z direction detection sensor 20 Dummy board 21 X direction detection slit 22 Y direction detection slit 30 Sensor signal processing device 40 Transfer robot 41 Robot arm 42 Fork 44 Pre-alignment device 50 Robot Control device 51 Host CPU
52 Operating device

Claims (2)

In an automatic teaching apparatus for a robot that transports a substrate to a semiconductor manufacturing apparatus by a robot arm,
A dummy substrate having a shape approximately the same as that of the substrate to be transported, and provided with slits separated in two dimensions in the X direction and the Y direction at predetermined positions;
An X-direction detection sensor and a Y-direction detection sensor that output position signals corresponding to the X-direction slit and the Y-direction slit on the dummy substrate, and a Z-direction perpendicular to the two dimensions of the X and Y directions. A sensor board provided with a Z-direction detection sensor for outputting a position signal;
An automatic teaching device for a robot, comprising: a signal processing device that outputs an absolute position signal from detection signals of the detection sensors in the X, Y, and Z directions. In an automatic teaching method of a robot that transports a substrate to a semiconductor manufacturing apparatus by a robot arm,
A dummy substrate having a shape approximately the same as that of the substrate to be transported, and provided with slits separated in two dimensions in the X direction and the Y direction at predetermined positions;
An X direction detection sensor and a Y direction detection sensor that output position signals corresponding to the X direction slit and the Y direction slit on the dummy substrate, and a Z direction that is perpendicular to the two dimensions of the X and Y directions. A sensor board provided with a Z-direction detection sensor for outputting a position signal;
A signal processing device that outputs an absolute position signal from detection signals of the detection sensors in the X direction, Y direction, and Z direction,
The sensor board is arranged at a reference position, the dummy board is mounted on the hand of the robot arm, and the dummy board is moved to a position where the three-dimensional position can be detected facing the sensor board. Teaching the robot arm using one point with a signal as a reference position,
Further, at the time of re-teaching, the dummy substrate is mounted on the hand of the robot arm, the dummy substrate is moved to a position where the three-dimensional position can be detected facing the sensor board, and the taught one point An automatic teaching method for a robot, wherein a reference position is automatically detected.

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