JPH10156773A - Method of acquiring teaching data for transferring machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten accuracy of teaching data in acquisition of teaching data used to drive a transferring machine by correcting position data, detected by a detecting means, on the basis of the disposed position of the detecting means for detecting the position data showing the position of the transfer machine at the time of transferring substrates. SOLUTION: In teaching operation of a transferring machine 4, the position of a jig is detected by a detecting means 10 in the state of the transferring machine 4 being fixed in a home position, and the obtained position data is stored in a memory 14. In acquisition of this position data, the position data detected by the detecting means 10 is subjected to specified temperature correction processing. In case of low temperature, for instance, sensor output voltage is read as initial data, and then sensor output voltage at specified temperature before actual processing is read. The difference value of these sensor output voltage is computed, and the correction value is obtained using this difference value. The position data stored in the memory 14 is then outputted to a controller 7 to put the transferring machine 4 in action.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for acquiring teaching data for a transfer machine, and more particularly, to a displacement of the teaching data for performing teaching on a transfer machine used in a vertical CVD apparatus, a diffusion apparatus, or the like. The present invention relates to a method for correcting a data error due to a temperature of a sensor.

[0002]

2. Description of the Related Art In a semiconductor manufacturing apparatus such as a CVD apparatus, a large number of wafers are loaded into a boat and loaded into a reaction furnace, and these wafers are subjected to processing such as film formation and annealing. The wafer before the processing and the wafer after the processing are accommodated in a cassette and transported. Therefore, these wafers are transferred and transferred between the boat and the cassettes on the cassette shelf by the transfer machine as the transfer robot.
This transfer machine has, for example, five tweezers, and can transfer five wafers at a time. This transfer machine
The wafer transfer / transfer processing is performed based on the control of the controller. That is, the wafer is scooped up from the cassette by the tweezer, and the transfer machine equipped with the tweezer turns, etc., and drives the tweezer again to load the wafer into the boat. At this time, it is necessary to accurately load the wafer into the loading groove of the boat column. Therefore, prior to the actual transport processing, the operation of the transfer machine including the tweezers is taught.

[0003] The teaching to the transfer machine is performed as follows. That is, before performing the actual process, as a pre-process, an operator places a detection jig (a quartz jig having the same size as the wafer) in the loading groove of the boat. Then, the clearance in the front-back direction, the left-right direction, and the up-down direction in the loading groove of the wafer-shaped jig is adjusted. In this state, the relative position of the jig is detected by the fixed position displacement sensor. This detection is performed by an optical displacement sensor. Specifically, the light from the light emitting element is irradiated on the jig, the reflected light is collected, and the position in each direction is detected. The data indicating each position is stored in the memory as teaching data,
In the actual processing process, the transfer machine is operated based on the stored teaching data. The displacement sensor is fixed to the transfer machine, and the displacement sensor performs the position measurement at the home position of the transfer machine.

[0004]

However, in obtaining such teaching data in the prior art, the temperature of the surroundings is changed by a displacement sensor disposed in the apparatus. However, no measures have been taken for the temperature change. As a result, an error in the jig position measurement has occurred due to a temperature change. Therefore, the teaching data obtained in this way contained errors. This error has an adverse effect on system accuracy. For example, a temperature change between ± 5 ° C. and 10 ° C. has a possibility of exceeding an allowable error on the system. Therefore, when the transfer machine is driven by such teaching data, the teaching accuracy is adversely affected. It is also conceivable to provide a temperature sensor separately and to correct the teaching data acquired by the displacement sensor. However, such a method has a problem that not only addition and change of hardware but also significant change in software is involved.

An object of the present invention is to improve the accuracy of teaching data in acquiring teaching data used for driving a transfer machine. Another object of the present invention is to improve teaching accuracy in an automatic teaching system including a transfer machine. Still another object of the present invention is to provide a method capable of providing hardware and software compatibility with a conventional system.

[0006]

According to the first aspect of the present invention, there is provided a transfer machine for transferring a substrate to a substrate loading position of a semiconductor manufacturing apparatus, wherein the substrate is transferred to the substrate loading position by the transfer machine. The position data indicating the position at the time is detected by the detecting means, and the teaching data for the transfer machine for obtaining the teaching data at the time of substrate transfer of the transfer machine based on the position data is obtained. This is a method of acquiring teaching data for a transfer machine, wherein the teaching data is acquired by correcting the position data detected by the detection means based on the temperature of the disposition position.

According to the first aspect of the present invention, when a substrate is mounted on a semiconductor manufacturing apparatus using a transfer machine, position data indicating the position of the transfer machine with respect to the substrate loading position of the semiconductor manufacturing apparatus is detected. Detect by means. Then, the position data is corrected based on the temperature of the position where the detection means is provided. Based on the corrected position data, teaching data indicating the position of the transfer device when the substrate is mounted is acquired.

For example, a semiconductor manufacturing apparatus includes a cassette shelf for holding a cassette, a boat for mounting semiconductor wafers, and a transfer machine (transfer robot) for transferring semiconductor wafers between the cassette and the boat in the room. Shall be.
At this time, a sensor is provided in this room, and the position data at the time of transferring the semiconductor wafer of the transfer machine is detected by the sensor, and the teaching data at the time of transferring the semiconductor wafer of the transfer machine based on the position data is detected. To get. In this case, the position data detected by the sensor is corrected based on the room temperature. Therefore, the acquired teaching data has an accurate temperature-corrected value, and does not hinder the teaching drive of the transfer machine at all, and guarantees an accurate operation.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for obtaining teaching data for a transfer machine according to the present invention will be described below. First, a semiconductor manufacturing apparatus for performing this method will be described with reference to FIGS. As shown in FIG. 1, a semiconductor manufacturing apparatus (for example, a vertical diffusion apparatus, a CVD apparatus, or the like) according to this embodiment is a vertical type in which a large number of semiconductor wafers 1 are loaded in order to perform predetermined processing in a reaction chamber. , A cassette 3 for accommodating a plurality of processed or unprocessed wafers 1, a transfer machine 4 for transferring five wafers 1 by 5 between the boat 2 and the cassette 3, and a transfer machine 4. And a controller 7 for controlling the transfer processing of the wafer 1. The cassette 3 is placed on a cassette shelf 6 provided in a room of the semiconductor manufacturing apparatus. Further, the transfer machine 4 has five tweezers 5 on the upper surface.

In the semiconductor manufacturing apparatus according to this embodiment, a sensor 10 as a detecting means is provided on the front surface of the transfer machine 4 (near the tweezers 5). The position data detected by the sensor 10 is input to an external terminal (PC: PC) 12 via an analog / digital converter 11. The detection means 10 is constituted by a sensor for optically detecting the position of the detection substrate (jig 21), and this detection information is output to the external terminal 12 as position data. Further, the semiconductor manufacturing apparatus is provided with communication control means 13 for controlling communication between the external terminal 12 and the controller 7. An operation command from the external terminal 12 is input to the controller 7 via the communication control means 13, and a status and an encoder value obtained by the controller 7 are input to the external terminal 12. This encoder value is the number of pulses generated by the drive motor of the transfer machine 4, whereby operation control can be performed while detecting the movement distance of the transfer machine 4 (movement distance of the tweezers 5).

The external terminal 12 is provided with a memory 14 (external storage device). The position data input from the detecting means 10 and the encoder value input from the controller 7 are stored in the memory 14. These position data and encoder value are data for controlling the operation of the transfer machine 4. In the transfer process of the wafer 1 in the actual process, the external terminal 12 and the controller 7 operate the transfer device 4 based on the data stored in the memory 14.

In order to obtain the position data, in a teaching operation performed prior to the actual process, a position detecting jig 2 shown in FIG.
1 is used. The jig 21 has a disk portion 21 a having the same shape and the same size as the wafer 1 and a disk portion 21.
and a column-shaped pin 21b erected at the center position of a. The entire jig 21 is made of quartz. By making the jig 21 from the same quartz as the boat 2, the boat 2 is not contaminated during the teaching operation. Further, the semiconductor manufacturing process can be maintained in a clean state.
Further, a cleaning process for maintaining cleanliness can be easily performed by existing equipment.

In the semiconductor manufacturing apparatus having the above-described structure, the teaching operation of the transfer machine is performed as described below, and thereafter, the transfer processing in the actual process is performed. First, in the teaching operation, an operator loads the position detecting jig 21 into the loading groove 8 of the boat 2. The clearance (clearance) between the jig 21 and the left and right boat columns 2a, the jig 21
The clearance (clearance) in the vertical direction with respect to the boat pillar 2a and the clearance (clearance) in the back of the jig 21 with respect to the boat pillar 2a are adjusted to be appropriate intervals. Next, in a state where the transfer machine 4 is fixed at a home position which is a reference position for the operation, the position of the jig 21 loaded on the boat 2 with a predetermined clearance is detected by the detecting means 10 and obtained in this detecting process. The stored position data is stored in the memory 14.

That is, as shown in FIG. 4A, the laser beam R is emitted from the detecting means 10 while rotating in the Y-axis direction (left-right direction). Then, the left and right ends of the pin 21b are detected from the presence or absence of the reflected light, and the bisected position (the center of the jig 21) is detected as the position of the jig 21 in the Y-axis direction. Also, as shown in FIG.
The laser beam R is irradiated while moving up and down in the Z-axis direction (vertical direction). Then, from the presence or absence of the reflected light, the disk portion 2
The edge 1a is detected, and the position is detected as the position of the jig 21 in the Z-axis direction. Further, as shown in FIG. 3C, the detecting means 10 detects the position of the pin 21b (center of the jig 21) in the X-axis direction (front-back direction) based on the reflected light from the pin 21b (ie, the jig). 21) and the transfer device 4).

In the above detection processing, in this embodiment, a light emitting element and a light position detecting element (PSD) are used as the detecting means 10.
Is used in combination with the optical displacement sensor. In particular, detection is performed by a method applying the triangulation method in the X-axis direction. The detection process by the sensor 10 will be described in more detail. Light from a light emitting element such as a light emitting diode or a semiconductor laser is condensed by a light projecting lens and irradiated to a jig 21. Then, a part of the light diffusely reflected from the jig 21 is focused on the light position detecting element through the light receiving lens. Based on the presence or absence of the collected light, the position in the Y-axis direction and the position in the Z-axis direction are detected, and the distance in the X-axis direction is detected based on the spot position of the collected light. That is, a voltage corresponding to the position of the spot where the light position detecting element of the reflected light condensed according to the distance between the sensor 10 and the jig 21 is formed is output. Is detected.

As described above, the sensor 10 as a whole has three functions of detecting the position in the Y-axis direction, the position in the Z-axis direction, and the distance in the X-axis direction. Note that the above detection processing is performed in a state where the transfer machine 4 and the tweezers 5 are installed at the home position. Alternatively, the position of the tweezer 5 can be accurately controlled in the actual process even if the positional relationship between the sensor 10 and the tip of the tweezer 5 is measured in advance and the operation is controlled by the position data obtained by the sensor 10. be able to.

In the acquisition of the position data by the detection processing, a predetermined temperature correction processing is performed on the position data detected by the displacement sensor 10. That is, when the sensor 10 is mounted in the room of the device, the zero point of the sensor 10 may be shifted due to the influence of the temperature change. In other words, the sensor output may fluctuate depending on the temperature. By correcting this deviation, an error from the detected position data can be removed. In addition,
The sensor 10 is of a type in which the output voltage changes linearly with the change in distance from the object to be measured (see FIG. 9).

Specifically, this correction is performed as follows. FIG. 9 is a graph showing a sensor output for explaining this correction. First, for example, when the temperature is low, the sensor output voltage La ₀ (indicating the distance between the sensor 10 and the cassette 3), Lb ₀ (the sensor 10 and the position detecting jig 21 (Indicating the distance from the pin 21b). This La, Lb
Indicates the distance between the transfer machine 4 and the cassette shelf 6 and the distance between the transfer machine 4 and the boat 2, respectively. The measurement by the sensor 10 can be performed in the state shown in FIGS. FIG. 5 shows a case where the transfer machine 4, the cassette 3, and the boat 2 are arranged on a straight line, and FIG. 6 shows a state where the transfer machine 4 is inclined at a predetermined angle with respect to this straight line. 7 shows the measurement of the distance between the transfer machine 4 and the boat 2 when the transfer machine 4 is also on a straight line, and FIG. 8 shows the measurement when the transfer machine 4 is positioned obliquely. The position data can be detected by the sensor 10 in any state of being aligned on a straight line or inclined.

Next, the output voltage L of the sensor 10 at a predetermined temperature before the actual process is used as teaching data.
a ₁ and Lb ₁ are read. This temperature is different from the initial value. The output Lb _{1 in} this case is data including a temperature error. The difference is the ambient temperature of the sensor 10. And L
A correction value Lb ₂ (a value corrected for the temperature error) of b ₁ is obtained.
That is, the difference value (Δ = La ₁ −La ₀ ) of the fixed distance (the distance between the sensor and the cassette, which is not a place to be adjusted by the user and is constant) at each temperature is calculated. Then, the value of Lb ₁ is corrected using this difference Δ to obtain Lb ₁
seek b _2. That is, (Lb ₂ = Lb ₁ + Δ). This Lb ₂ becomes the position data corrected for the temperature error. In this way, it is possible to correct an error due to a temperature change of the displacement sensor 10. This position data becomes teaching data.

Therefore, the position data at which the jig 21 (ie, the wafer 1) can be loaded into the boat 2 in an appropriate state with a predetermined clearance is stored in the memory 14
Is stored in In the actual process thereafter, the position data stored in the memory 14 is output to the controller 7, and the transfer device 4 is operated. Then, the wafer 1 is loaded into the loading groove 8 of the boat 2 with appropriate clearances in the front-rear direction, the left-right direction, and the up-down direction. In this embodiment, the five tweezers 5 of the transfer machine 4 simultaneously carry the wafers 5 one by one and load the wafers 1 into the boat 2 with a predetermined clearance.

[0021]

According to the present invention, the teaching accuracy of the transfer machine can be maintained regardless of the temperature around the sensor. In addition, correction on the system can be performed even when the zero point of the sensor is misaligned due to a temperature change. Furthermore, temperature correction can be performed on the acquired position data without using a new temperature sensor.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a semiconductor manufacturing apparatus according to one embodiment of the present invention.

FIG. 2 is a perspective view showing a position detecting jig according to one embodiment of the present invention.

FIG. 3 is a perspective view showing a state in which a position detecting jig according to one embodiment of the present invention is loaded into a boat.

FIG. 4 is a schematic diagram for explaining a state of acquisition of position data by a sensor in the semiconductor manufacturing apparatus according to one embodiment of the present invention.

FIG. 5 is a schematic diagram for explaining detection of position data by a sensor in the semiconductor manufacturing apparatus according to one embodiment of the present invention.

FIG. 6 is a schematic diagram for explaining detection of position data by a sensor in the semiconductor manufacturing apparatus according to one embodiment of the present invention.

FIG. 7 is a schematic diagram for explaining detection of position data by a sensor in the semiconductor manufacturing apparatus according to one embodiment of the present invention.

FIG. 8 is a schematic diagram for explaining detection of position data by a sensor in the semiconductor manufacturing apparatus according to one embodiment of the present invention.

FIG. 9 is a graph showing a sensor output according to one embodiment of the present invention.

[Explanation of symbols]

 1 semiconductor wafer, 2 boat, 3 cassette, 4 transfer machine, 5 tweezer, 6 cassette shelf, 10 sensor, 21 jig for position detection.

Claims (1)

[Claims] In a transfer machine for transferring a substrate to a substrate loading position of a semiconductor manufacturing apparatus, position data indicating a position of the transfer machine with respect to the substrate loading position at the time of substrate transfer is detected by a detecting means. In the method of acquiring teaching data for a transfer machine for acquiring teaching data at the time of transfer of a substrate by the transfer machine based on the position data, the detecting means detects the temperature based on a temperature of an arrangement position of the detecting means. A method for acquiring teaching data for a transfer machine, wherein the teaching data is acquired by correcting the set position data.