JPH0714908A - Substrate transfer device - Google Patents

Abstract

PURPOSE:To make possible the modification of a transfer in/out position of a substrate by detecting a mechanical error generated in a transfer robot as it is used. CONSTITUTION:A positioning pin 8 for mechanical error detection is raised and provided in a normal substrate transfer in/out position by servo control of a transfer robot. A recessed part 11 is provided to a tip of arms 12A, 12B of the transfer robot 1, and the recessed part 11 is fitted to the positioning pin 8 at a position in proportion to a mechanical error of the transfer robot 1. A mechanical error of the transfer robot 1 is detected based on a deviation amount of the recessed part 11 to the position pin 8, a modification signal of a transfer in/out position is output and the transfer in/out position of a substrate is modified by the detection position modification signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate transfer device,
In particular, the present invention relates to a substrate transfer device that transfers a semiconductor substrate by a transfer robot.

[0002]

2. Description of the Related Art FIG. 5 is a schematic view showing a plasma vapor deposition apparatus which is one of conventional semiconductor manufacturing apparatuses. The outline of the device will be described. The transfer robot 1 on the loader side 13 a takes out one semiconductor substrate (hereinafter referred to as a wafer) 2 from the three carriers 3 and transfers it to the front of the load lock door 5. The load lock door 5 is normally closed, and the load lock door 5 is opened when the transfer robot 1 transfers the wafer to the wafer receiver 6 in the reactor. After the load lock door 5 is opened, the transfer robot 1 enters the reaction furnace side 13b, places the wafer 2 on the wafer receiver 6, and returns to the position shown in FIG. Then, the load lock door 5 is closed and the reaction furnace is evacuated to grow a thin film on the wafer 2 in a plasma state.

After the work in the reaction furnace is completed, the load lock door 5 is opened, and the transfer robot 1 takes out the semiconductor wafer 2 on the reaction furnace side 13b and transfers it to the carrier 3 on the loader side 13a.

Next, the operation of the transfer robot will be described. As shown in FIGS. 6 and 7, the transfer robot 1 is configured to extend and retract the wafer table 4 back and forth by two arms 12A and 12B. Arms 12A and 12B of the transfer robot
Is servo-controlled by three servo motors in the up, down, left and right directions, and the positioning of the carrier and the arm in the reaction furnace is determined by a program. When the wafer 2 is picked up, the left and right control motors of the transfer robot 1 perform left and right alignment, then the up and down control motors perform up and down alignment, and finally the front and rear control motors place the wafer table on the wafer table. Take. The same movement is performed when returning the wafer 2 to the carrier 3.

[0005]

When a wafer is transferred by this conventional apparatus, an accident such that the transfer robot 1 suddenly contacts the wafer receiver 6 occurs about once a month. When a contact accident occurs, the wafer 2 is not placed on the wafer receiver 6, the wafer 2 is broken, and the apparatus may need to be cleaned, resulting in a significant decrease in operating rate.

When analyzing the cause of the accident, it is often because the left and right arms 12A and 12B of the transfer robot 1 are out of balance. The substrate supporting arm is a double arm that moves the wafer table 4 back and forth by two arms 12A and 12B as shown in FIG. When used for a long time, the spring forces of the left and right arms change, and the magnitude of friction of the shaft also changes, so it is considered that the left and right arms 12A and 12B are out of balance. Therefore, even if the computer returns to the original position, the arm is slightly deviated to the left and right during the transfer, and the wafer catches on the wafer receiver 6.

It is an object of the present invention to provide a substrate transfer apparatus which detects a mechanical error caused in a transfer robot during use and corrects the substrate loading / unloading position by the transfer robot based on the detected data. It is in.

[0008]

In order to achieve the above-mentioned object, a substrate transfer apparatus according to the present invention has an error detection mechanism and allows a transfer robot to support a prescribed number of semiconductor substrates.
A substrate transfer device that transfers the substrate by a transfer robot and stops it at a predetermined position, wherein the transfer robot is servo-controlled, and the error detection mechanism is a regular transfer of the substrate by servo control of the transfer robot. The position is used as an initial value, the deviation of the loading / unloading position of the board based on the secular change with respect to the initial value is detected, and the correction signal of the loading / unloading position is output. It represents the mechanical error of the robot.

Further, the error detecting mechanism has a positioning pin and a concave portion, and the positioning pin is provided upright at a regular substrate loading / unloading position by servo control of the transfer robot, and the concave portion is The positioning pin is externally mounted on the positioning robot, is provided at the tip of the substrate supporting arm of the transfer robot so as to face the positioning pin, and engages with the positioning pin at a position proportional to the mechanical error of the transfer robot.

Further, the error detecting mechanism has a pair of a light emitting portion and a light receiving portion, and one of the light emitting portion and the light receiving portion is fixedly provided at a regular substrate loading / unloading position by servo control of the transfer robot, The other is provided in the transfer robot, and the light emitting unit is
The light emitting unit emits light, and the light receiving unit receives the light amount proportional to the mechanical error of the transport robot from the light emitting unit.

[0011]

Operation: The normal substrate carry-in / carry-out position under servo control of the carrier robot is used as an initial value, a shift in the carry-in / carry-out position of the substrate due to secular change with respect to the initial value is detected, and the substrate is carried by the carrier robot based on the detected data Correct the loading / unloading position of.

The shift of the loading / unloading position of the substrate due to the secular change occurs due to the mechanical error of the transport robot due to use.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing Embodiment 1 of the present invention, and FIG. 3 is a view showing an error detection mechanism used in Embodiment 1 of the present invention.

FIG. 1 shows a plasma vapor phase growth apparatus. The apparatus is divided into a loader door (housing portion) 13a and a reactor side (processing portion) 13b by a load lock door 5, and a loader side 13a. A carrier 3 is installed inside, and the wafer 2 is loaded and unloaded by the transfer robot 1 between the loader side 13a and the reaction furnace side 13b. This structure is the same as the conventional one.

The present invention has an error detection mechanism. The error detection mechanism is designed to set a normal substrate loading / unloading position under servo control of the transport robot 1 as an initial value, and detect a deviation of the substrate loading / unloading position due to secular change with respect to the initial value. 28 and the recessed portion 11. The deviation of the loading / unloading position of the substrate due to the secular change occurs based on a mechanical error of the transfer robot 1. The mechanical error of the transfer robot 1 is caused by the left and right arms 12
It is caused by changes in the force of springs A and 12B, friction of the shaft, and the like.

As shown in FIGS. 1 and 3, a positioning pin 8 is provided.
Are planted upright at a proper substrate loading / unloading position under the servo control of the transport robot 1. The recessed portion 11 is to be installed on the positioning pin 8 and is engraved on the wafer receiver 6 provided at the tip of the substrate supporting arms 12a and 12B of the transfer robot 1 so as to face the positioning pin 8 and to face the transfer robot 1. The positioning pin 8 is engaged at a position proportional to the mechanical error of the.

The operation of this embodiment will be described. First, the transfer robot 1 has a wafer 2 stored in a carrier 3.
Take it out and move it to the front of the reactor. Before inserting the wafer 2 into the reaction furnace, the positioning pins 8 installed on the load lock door 5 perform positioning once to make fine adjustments in the vertical and horizontal directions. The wafer 2 can be placed in the reaction furnace without contact with the wafer.

A positioning method using the positioning pin 8 will be described with reference to FIG. The tip of the wafer table 4 is a recessed portion 11 which is equivalent to one pin. At the time of positioning, the transfer robot 1 moves forward until the positioning pin 8 enters the recess 11. The positioning pin 8 enters the concave portion 11,
When it contacts the wafer table, an electric signal flows, and it is judged that the device has contacted, and it stops. Next, the left and right motors move the transfer robot to the left and right, and the side walls 11a and 11a at both ends of the recessed portion 11 are moved.
When the pin 8 comes into contact with, the left and right positions are determined and the center position is detected.

When the transport robot is moved up and down by the up and down motor and the recess 11 is separated from the positioning pin 8, no current flows. Then, the position when the positioning pin 8 is separated is determined and the position in the vertical direction is detected. In this way, the mechanical error of the transfer robot 1 due to use is detected, and the detection data is added to correct the substrate loading / unloading position by servo control of the transfer robot. As a result, wafer cracks due to contact accidents can be eliminated, and the operating rate is improved from 40% to 60%.

(Second Embodiment) FIGS. 2 and 4 are views showing a second embodiment of the present invention. In the above embodiment, since the positioning is performed at the time of putting in and out, the throughput is deteriorated,
In this embodiment, the throughput is improved.

The operation of the transfer robot 1 is the same, but before the transfer robot 1 enters the wafer receiver 6 in the reaction furnace, the wafer base 4 of the transfer robot 1 and the optical sensor 7 installed in the reaction furnace are used. Fine adjustments are made on the top, bottom, left, and right to set it to the specified position. The optical sensor 7 includes a pair of a light irradiation device 14 as a light emitting unit and a light receiving unit. Here, the optical sensor 7 will be described.

A light irradiation device 14 for irradiating light is attached to the transfer robot 1, and a sensor for detecting light is attached to the wafer receiver 6. As shown in FIG. 4, the detection sensor 10 is provided with a slit 9 having a hole as a light receiving portion on the front side. The slit 9 has the largest hole in the center, and the smaller holes line up toward the periphery. When the light is emitted, the light passes through the hole of the slit 9 and the detection sensor 1
It corresponds to 0. At this time, the light hitting the slit does not reach the detection sensor 10. The detection sensor 10 generates an electric current according to the amount of light that reaches it, and when a certain amount of electric current is secured (when light enters a large hole in the middle), the transfer robot 1
Determines that it has been set to the specified position and stops. The transfer robot 1 repeats the fine adjustment of the position until it can secure a certain amount of current, and moves in a direction in which more current can be secured.

As a result, the transfer robot 1 can correct the position accurately even if the stop position is displaced due to a mechanical error. As described above, according to the present embodiment, the positional deviation of the transfer robot 1 can be brought to a predetermined position by detecting and correcting the vertical and horizontal directions of the transfer robot. As a result, the contact accident of the transfer robot 1 was eliminated, the throughput was improved, and the operating rate of the apparatus for one month was increased from 40% to 70%.

Although the present invention shows an example of transportation of the plasma vapor phase growth apparatus, the present invention can be applied to other vacuum system apparatuses.

[0026]

As described above, according to the present invention, the normal substrate loading / unloading position under the servo control of the transfer robot is used as an initial value, and a deviation due to a mechanical error of the transfer robot with respect to the initial value is detected and detected. Since the loading / unloading position of the substrate is corrected based on the data, it is possible to solve the accident that the substrate supporting arm of the transfer robot is brought into contact with the wafer receiver to damage the wafer.

Further, by using the optical sensor as the error detecting mechanism, the error can be detected without contact, and the operation rate of the apparatus can be improved without temporarily stopping the apparatus when correcting the position.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of the present invention.

3A is a plan view showing an error detection mechanism used in Embodiment 1 of the present invention, and FIG. 3B is a side view of the same.

FIG. 4 is a diagram showing an error detection mechanism used in a second embodiment of the present invention.

FIG. 5 is a configuration diagram showing a conventional vapor phase growth apparatus.

FIG. 6 is a plan view showing a conventional transfer robot.

FIG. 7 is a side view showing a conventional transfer robot.

[Explanation of symbols]

 1 Transfer Robot 2 Semiconductor Substrate (Wafer) 3 Carrier 4 Wafer Stand 5 Load Lock Door 6 Wafer Receiver 7 Optical Sensor 8 Positioning Pin 9 Slit 10 Sensing Sensor 11 Recess 12A, 12B Arm 14 Light Irradiator

Claims (3)

[Claims] 1. A substrate transfer device having an error detection mechanism, supporting a prescribed number of semiconductor substrates by a transfer robot, transferring the substrates by the transfer robot, and stopping the substrates at a predetermined position. The error detection mechanism sets the normal board loading / unloading position by servo control of the transfer robot as an initial value, detects the deviation of the board loading / unloading position based on the secular change with respect to the initial value, and carries out the unloading. A substrate transfer apparatus, which outputs a correction signal of an in / out position, and the correction signal of the in / out position represents a mechanical error of a transfer robot during use. 2. The error detecting mechanism has a positioning pin and a recess, and the positioning pin is provided upright at a regular substrate loading / unloading position under servo control of the transfer robot, and the recess is It is to be mounted on the positioning pin, is provided at the tip of the substrate supporting arm of the transfer robot so as to face the positioning pin, and engages with the positioning pin at a position proportional to the mechanical error of the transfer robot. The substrate transfer apparatus according to claim 1, which is characterized in that. 3. The error detection mechanism has a pair of a light emitting portion and a light receiving portion, and one of the light emitting portion and the light receiving portion is fixedly provided at a regular substrate loading / unloading position under servo control of a transfer robot, The other is provided in the transfer robot, the light emitting unit emits light, and the light receiving unit receives the light amount proportional to the mechanical error of the transfer robot from the light emitting unit. The substrate transfer device according to claim 1.