KR102406275B1 - Apparatus for correcting error of robot arm - Google Patents

Abstract

The present invention relates to an error correcting device for a robot arm, and the robot arm error correcting device according to an embodiment of the present invention is a device for correcting an error caused by repeated movement of the robot arm, and a reflector mounted on the robot arm. a light irradiator for irradiating a plurality of incident lights; a projection unit on which the plurality of incident lights are irradiated to the reflecting plate and the plurality of reflected lights are projected; an error measuring unit for measuring an error according to repeated movement of the robot arm through a positional deviation between the plurality of reflected lights; and an error correcting unit for correcting the error of the robot arm by using the error measured by the error measuring unit.

Description

Apparatus for correcting error of robot arm

The present invention relates to an error correction device for a robot arm. Specifically, the present invention relates to a technique for measuring an error of a robot arm using a laser and correcting an error of the robot arm through the measured error.

In a semiconductor manufacturing process, a photolithography process is a process of forming a desired resist pattern by applying a resist solution to a wafer substrate and exposing and developing using a photomask. This photolithography process includes transferring a wafer substrate through a substrate transfer device to a processing unit (or process chamber) that processes resist solution application, exposure, and development. Therefore, the substrate transfer apparatus needs to accurately set the position of the transfer robot in order to accurately supply wafers to each processing unit.

For example, a semiconductor manufacturing facility such as a spinner system or a scrubber has a plurality of processing units, and a wafer is transferred to the processing unit by a transfer robot. The processing unit performs each process, and the wafer is transferred to the outside by the transfer robot again. At this time, it is very important that the wafer is accurately placed in the set position of the plate in the processing unit. If the wafer is incorrectly placed on the plate in the bake module or the coating module, process errors such as failure to uniformly heat the entire wafer or failure to uniformly apply photoresist may occur.

To this end, a teaching operation is performed to adjust the position of the transfer robot before the process proceeds so that the wafer can be loaded into the correct position of the plate or the spin chuck in the processing unit.

On the other hand, there is a case where the movement position of the transfer robot for loading wafers into each process module deviates from the initially set position due to collision with the input window or plate of the processing unit or wear of the transfer robot while the transfer robot transfers the wafer. often occurs

In this case, by moving the transfer robot differently from the taught position when the transfer robot operates, the wafer may not be picked up accurately and the wafer may be damaged. In addition, as the wafer is damaged, other wafers in the load lock chamber are also damaged, causing lot-unit losses. Furthermore, when an abnormality occurs in the wafer in the buffer chamber, the wafer is removed by opening the buffer chamber, and the transfer robot must be disassembled and inspected.

Therefore, there is a need to accurately measure how much the movement position of the transfer robot deviated from the initially taught position, that is, an error.

Japanese Patent Laid-Open No. 2002-313872

An object of the present invention is to provide a technique for measuring and correcting an error of a robot arm that performs repetitive tasks using a laser.

An apparatus for correcting an error of a robot arm according to an embodiment of the present invention comprises: a light irradiator for irradiating a plurality of incident lights to a reflector mounted on the robot arm; a projection unit on which the plurality of incident lights are irradiated to the reflecting plate and the plurality of reflected lights are projected; an error measuring unit for measuring an error according to repeated movement of the robot arm through a positional deviation between the plurality of reflected lights; and an error correcting unit for correcting the error of the robot arm by using the error measured by the error measuring unit.

In an embodiment, the light irradiator may be disposed on a drive shaft of the robot arm.

In one embodiment, the light irradiation unit includes a plurality of lasers, each of the plurality of lasers may be respectively disposed on a drive shaft of the robot arm.

In one embodiment, the camera unit for measuring a positional deviation between the plurality of reflected light projected on the projection unit may be further included.

In an embodiment, the error measuring unit may measure an error according to the repeated movement of the robot arm through a positional deviation between the plurality of reflected lights measured by the camera unit.

In an embodiment, the error measuring unit may measure a rotation error and a position error according to the repeated movement of the robot arm.

The present invention measures and corrects an error of a robot arm that performs repetitive tasks using a laser.

Accordingly, there is an effect of measuring and correcting the error of the robot arm performing repetitive tasks with a simple configuration.

Accordingly, there is an effect that the time and cost for measuring and correcting the error of the robot arm performing repetitive tasks are significantly reduced.

1 is a block diagram illustrating a conceptual configuration of an error correction device for a robot arm according to an embodiment of the present invention.
2 is a view showing the arrangement state of the robot arm and the error correction device of the robot arm according to an embodiment of the present invention.
3 is a view illustrating an exemplary reflector mounted on a robot arm.
4 is a diagram illustrating a process of measuring an error of the robot arm in the error correction apparatus of the robot arm according to an embodiment of the present invention.
5 is a diagram illustrating a process of measuring an error of a robot arm through a plurality of lasers in an error correction apparatus for a robot arm according to an embodiment of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly defined in particular.

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, “comprises” and/or “comprising” does not exclude the presence or addition of one or more other components in addition to the stated components.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

1 is a block diagram illustrating a conceptual configuration of an error correction device for a robot arm according to an embodiment of the present invention. At this time, the robot arm 1 refers to a robot that performs repetitive tasks in a semiconductor manufacturing process, etc., and the present invention relates to a technology for correcting an error caused by the position of the robot arm 1 being shifted while performing repetitive tasks. will be.

Referring to FIG. 1 , an error correction apparatus 100 for a robot arm according to an embodiment of the present invention includes a light irradiator 110 , a projection unit 120 , a camera unit 130 , an error measurement unit 140 , and an error. A correction unit 150 is included.

The light irradiation unit 110 irradiates a plurality of incident lights to the reflector 2 mounted on the robot arm 1 . The projection unit 120 is the plurality of incident light is irradiated to the reflecting plate 2, the reflected plurality of reflected light is projected. The camera unit 130 measures a positional deviation between the plurality of reflected lights projected on the projection unit 120 . The error measuring unit 140 measures an error according to the repeated movement of the robot arm 1 through the positional deviation between the plurality of reflected lights. The error correcting unit 150 corrects the error of the robot arm 1 by using the error measured by the error measuring unit 140 .

Hereinafter, the configuration of the error correction apparatus 100 of the robot arm according to an embodiment of the present invention will be described in detail.

2 is a view showing the arrangement state of the robot arm and the error correction device of the robot arm according to an embodiment of the present invention.

Referring to FIG. 2 , the robot arm 1 as a target for which the error correction apparatus 100 of the robot arm according to an embodiment of the present invention corrects an error may be identified. The robot arm 1 refers to a robot that performs repetitive tasks in a semiconductor manufacturing process or the like. The robot arm 1 is equipped with a reflector 2 on one side.

The light irradiator 110 is disposed on the drive shaft of the robot arm 1 and irradiates a plurality of incident lights to the reflector 2 . Specifically, the plurality of incident lights emitted from the light irradiation unit 110 are irradiated to the reflecting plate 2 through the projection unit 120 . The plurality of incident lights irradiated to the reflective plate 2 are reflected in a predetermined direction by the reflective plate 2 , respectively. In this case, the light irradiation unit 110 is disposed so that a plurality of reflected light reflected from the reflecting plate 2 is incident on the projection unit 120 .

The projection unit 120 is disposed so that the plurality of reflected lights reflected from the reflecting plate 2 are projected to a reference position. The reference position means a position where the plurality of reflected lights are projected when there is no error because the position of the robot arm 1 is not shifted. Accordingly, when an error occurs because the position of the robot arm 1 is shifted, the plurality of reflected lights are projected to a position different from the reference position. That is, when an error of the robot arm 1 occurs, a positional deviation occurs between the plurality of reflected lights on the projection unit 120 .

The camera unit 130 measures a positional deviation between the plurality of reflected lights projected on the projection unit 120 . Specifically, the camera unit 130 includes the reflected light projected to a position different from the reference position among the plurality of reflected lights projected to the projection unit 120 through the image captured by the projection unit 120 and the reflected light projected to the reference position. Measure the positional deviation between reflected light.

The error measuring unit 140 measures an error according to the repeated movement of the robot arm 1 through the position deviation measured by the camera unit 130 . This will be described later with reference to FIG. 4 .

The error correcting unit 150 corrects the error of the robot arm 1 by using the error measured by the error measuring unit 140 . Specifically, the error correcting unit 150 returns the position of the robot arm 1 to the position before the error occurred by using the error measured by the error measuring unit 140 . For example, as a result of measurement by the error measuring unit 140, when the robot arm 1 is misaligned by 5 mm in the +x-axis direction, the error correcting unit 150 sets the position of the robot arm 1 in the -x-axis direction. The error of the robot arm (1) can be corrected by returning it by 5 mm.

3 is a view illustrating an exemplary reflector mounted on a robot arm.

Referring to FIG. 3 , it can be seen that the reflective plate 2 mounted on the robot arm 1 is formed in a cylindrical shape. At this time, when the reflective mirror 3 of the reflective plate 2 is formed in a sphere shape, the light incident to the center of the reflective mirror 3 is directly reflected in the incident direction regardless of the incident angle.

Therefore, when the light irradiator 110 is arranged so that the light irradiated from the light irradiator 110 is incident on the center of the reflective mirror 3, if there is no error in the robot arm 1, the light irradiated from the light irradiator 110 is It is reflected from the center of the reflection mirror 3 and is projected to the reference position of the projection unit 120 . However, when an error occurs in the robot arm 1 , the light irradiated from the light irradiator 110 is reflected at a point other than the center of the reflective mirror 3 and is projected to a position different from the reference position among the projection unit 120 . do.

4 is a diagram illustrating a process of measuring an error of the robot arm in the error correction apparatus of the robot arm according to an embodiment of the present invention. At this time, FIG. 4 is illustrated on the assumption that an error occurs in the robot arm 1 . On the other hand, the error generated in the robot arm 1 includes a position error and a rotation error.

In FIG. 4 , the distance from the rotation axis of the robot arm 1 to the grip of the robot arm 1 is d, the distance from the grip of the robot arm 1 to the projection unit 120 is d', and the projection unit 120 is When a' is the positional error between the projected plurality of reflected lights, a is the positional error of the robot arm 1, and Φ is the rotational error of the robot arm 1, the positional error of the robot arm 1 is expressed by the following equation equal to 1.

In addition, the rotation error of the robot arm 1 is as shown in Equation 2 below.

For example, when d = 0.5 m, d' = 1 m, and a' = 0.01 m, the position error of the robot arm 1 measured by the error measuring unit 140 a = 3.3 mm, the robot arm 1 The rotation error of Φ = 0.38°.

At this time, when the reference position is a0' and some of the plurality of reflected lights are projected on a1', the error direction of the robot arm 1 is from a0' to a1'.

5 is a diagram illustrating a process of measuring an error of a robot arm through a plurality of lasers in an error correction apparatus of a robot arm according to an embodiment of the present invention.

Referring to FIG. 5 , the light irradiation unit 110 includes a plurality of lasers 111 , 112 , and 113 , and the projection unit 120 includes a plurality of projection plates 121 , 122 and 123 to the robot arm 1 . ), it can be seen that they are respectively arranged on the drive shaft. Specifically, when the driving axis of the robot arm 1 is the x-axis, the y-axis, and the z-axis, the plurality of lasers 111 , 112 , 113 and the plurality of projection plates 121 , 122 , 123 of the robot arm 1 are It is arranged on each of the x-axis, y-axis, and z-axis, which are the driving axes.

As shown in FIG. 5 , a plurality of lasers 111 , 112 , 113 and a plurality of projection plates 121 , 122 , 123 are disposed on the driving shaft of the robot arm 1 , respectively, and an error caused by the repeated movement of the robot arm 1 . In the case of measuring , the accuracy and reliability of error measurement may be improved.

Those of ordinary skill in the art to which the present invention pertains will understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential features thereof. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention. do.

1: Robot arm
2: reflector
100: error correction device of the robot arm
110: light irradiation unit
120: projection unit
130: camera unit
140: error measuring unit
150: error correction unit

Claims (6)

An apparatus for correcting an error caused by repeated movement of a robot arm, the apparatus comprising:
a light irradiator for irradiating a plurality of incident lights to the reflector mounted on the robot arm;
a projection unit on which the plurality of incident lights are irradiated to the reflecting plate and projecting the reflected plurality of reflected lights;
a camera unit for photographing the projection unit on which the plurality of reflected lights are projected, and measuring a positional deviation between the plurality of reflected lights with reference to an image generated by photographing the projection unit;
an error measuring unit measuring an error according to repeated movement of the robot arm through a positional deviation between a plurality of reflected lights measured by the camera unit; and
An error correction unit for correcting the error of the robot arm by using the error measured by the error measuring unit,
The camera unit checks the positional deviation between the reference position included in the projection unit and the reflected light projected on the projection unit through the image, and measures the positional deviation between the plurality of reflected lights with reference to the confirmed result,
The reference position is an error correction device for a robot arm, which means a position at which the plurality of reflected lights are projected when there is no error because the position of the robot arm is not shifted. According to claim 1,
The light irradiator is an error correcting device for a robot arm disposed on a drive shaft of the robot arm. 3. The method of claim 2,
The light irradiation unit includes a plurality of lasers,
Each of the plurality of lasers is an error correction device for a robot arm that is respectively disposed on a drive shaft of the robot arm. According to claim 1,
The error measuring unit measures the position error of the robot arm, and satisfies Equation 1 below,
[Equation 1]
a = a'd(d+d')
In Equation 1, a denotes a position error of the robot arm, a' denotes a positional deviation between the plurality of reflected lights projected on the projection unit, and d denotes a grip of the robot arm on the rotation axis of the robot arm. means a distance to, and d' is a distance from the grip of the robot arm to the projection unit. The method of claim 1,
The error measuring unit measures the rotation error error of the robot arm, and satisfies Equation 2 below,
[Equation 2]
Φ = tan ^-1 a'(d+d')
In Equation 2, Φ denotes a rotation error of the robot arm, a' denotes a positional deviation between the plurality of reflected lights projected on the projection unit, and d denotes a grip of the robot arm on the rotation axis of the robot arm. means a distance to, and d' is a distance from the grip of the robot arm to the projection unit. According to claim 1,
The error measuring unit is an error correction device for a robot arm that measures a rotation error and a position error according to the repeated movement of the robot arm.

Images