WO2005036635A1

WO2005036635A1 - Teaching tool for semiconductor wafer carrying robot

Info

Publication number: WO2005036635A1
Application number: PCT/JP2004/015060
Authority: WO
Inventors: Masaru Adachi; Mitsunori Kawabe
Original assignee: Kabushiki Kaisha Yaskawa Denki
Priority date: 2003-10-14
Filing date: 2004-10-13
Publication date: 2005-04-21
Also published as: JP4501102B2; JP2005123261A

Abstract

A teaching tool (11) enabling an increase in accuracy for estimating the position of a wafer, the accurate positioning thereof even in a device of such type that supports the wafer by a pin, and the self-collection thereof by the robot. The teaching tool (11) teaches the position of the wafer to the robot by putting the wafer on a wafer loading part and detecting a detected part by a light transmission type sensor installed on the hand (5) of the robot. The teaching tool comprises a large disk part (12) having the same outer diameter as that of the wafer, a small circular pin (22) positioned co-axial with the large disk part (12), and an arch-shaped member (26) positioned co-axial with the large disk part (12). The teaching tool is formed such that a distance between the center of the large disk part (12) and the outer circular part of the arch-shaped member (26) is equal to a distance between the optical axis (10) of the sensor and the center (29) of the wafer loading part of the hand (5).

Description

Teaching tool for semiconductor wafer transfer port pot

Technical field

The present invention relates to a teaching jig for teaching a position of a semiconductor wafer to a semiconductor wafer transport robot.

Background art

[0002] Conventionally, in a teaching operation of a semiconductor wafer transfer robot, an operator visually looks at a transfer target wafer, confirms a position of the transfer target wafer, and guides the robot to the wafer, similarly to a general industrial robot. I was However, it is sometimes difficult or impossible to visually observe a wafer inside a processing apparatus or the like from the outside. Therefore, a teaching jig having the same dimensions as the actual wafer is placed on a processing device or the like instead of the wafer, and the position of the teaching jig is detected by a sensor provided in the end effector of the robot, and the position is determined by the robot. A so-called auto-teaching method and device for teaching has been proposed! Puru.

[0003] The inventor of the present invention has previously proposed in Patent Document 1 a method of sensing a teaching jig using a hand having two transmitted light sensors. In this method, the hand approaches the small disk provided on the teaching jig from different directions, and the result is applied to the teaching position of the robot, that is, the cylindrical coordinate system (R-θ-Z ), R value, Θ value, and Z value are calculated. Here, the R value indicates the teaching value of the robot arm in the extension and contraction direction, the Θ value indicates the teaching value of the robot in the rotation direction, and the Z value indicates the teaching value of the robot in the vertical direction.

Patent Document 1: International Publication No. WO03Z22534

Disclosure of the invention

Problems to be solved by the invention

[0004] In the apparatus disclosed in Patent Document 1, the direction in which the hand approaches the teaching jig and the posture of the hand when the teaching jig is detected by the sensor are determined when the robot actually transports the wafer or the like. Therefore, the accuracy of estimating the teaching position automatically calculated by sensing cannot be satisfied unless the relative movement accuracy of the robot is guaranteed. Also, inside a narrow processing unit, there was a problem that it was not possible to change the direction and approach the hand to the small disk! /, And! /.

In addition, since the teaching jig has the same diameter as the wafer, it can be easily positioned by pressing it into a slot in a station such as a cassette. A force that supports the wafer with three pins, or a wafer mounting position with a drop-in shape However, there is a problem that it is difficult to position the teaching jig in a station that has a tolerance and a station that receives a wafer on a cylindrical support such as a bria liner.

In addition, since the work of removing the teaching jig from the station force is performed manually after the end of the automatic teaching, there has been another problem that in the case of a processing device or the like, it takes time to open the station lid or the like.

The present invention has been made in view of such a problem, and improves the accuracy of estimating the position of the teaching jig and accurately positions the teaching jig even in a device that supports a wafer with pins. It is another object of the present invention to provide a teaching jig capable of automatically collecting the teaching jig by the robot itself.

Means for solving the problem

In order to solve the above-described problem, the present invention is a teaching jig for teaching a position of a transfer target wafer to a robot for transferring a semiconductor wafer, and mounts the wafer in place of the transfer target wafer. Teaching the robot to teach the robot the position of the wafer by placing it on a location and detecting the detected part provided on the teaching jig by a transmitted light type sensor provided on the hand of the robot. A jig, a large disk portion having the same outer diameter as the wafer, a small circular pin having a common central axis with the large disk portion, and an arch-shaped object having a common central axis with the large disk portion; Teaching teaching so that the distance from the center of the large disk portion to the outer circle portion of the arch-shaped object is equal to the optical axis force of the sensor to the center of the wafer mounting portion of the hand. It constitutes a tool. Further, a groove is provided on the back surface of the teaching jig to be fitted with a wafer support pin of the processing apparatus. Further, the teaching jig is configured so that it can be gripped by the hand in the same manner as the object to be transported.

The invention's effect According to the present invention, since the teaching jig can be detected by the sensor on the hand in the same posture as the posture on which the robot places the wafer, accurate teaching can be performed even when the relative movement accuracy of the robot is poor. There is an effect that can be. In addition, since the small circular pin having a small diameter is used as the detection target, there is an effect that the teaching jig can be detected in a posture close to the posture at the time of actual carrying in and out without largely changing the posture of the hand. In addition, since an arch-shaped object having the same central axis as the teaching jig is used as the detection target, there is no problem even if the direction of the rotation direction when the teaching jig is set is shifted by a predetermined angle. There is an effect that the installation of the jig is easy. In addition, since there is a groove on the back surface of the teaching jig so that the teaching jig fits into the shape of the wafer installation surface of the station, there is an effect that it is easy to correctly install the teaching jig. In addition, since the robot can be actually grasped by the hand of the robot, the teaching jigs installed at a plurality of stations can be recovered by the robot itself after the end of the automatic teaching, and the teaching time can be shortened.

Brief Description of Drawings

FIG. 1 is a plan view of a robot used for implementing the present invention.

FIG. 2 is a plan view of a robot used for implementing the present invention.

FIG. 3 is a side view of a robot used for implementing the present invention.

FIG. 4 is an explanatory diagram of a transmitted light sensor used for implementing the present invention.

FIG. 5 is an explanatory diagram of a teaching jig showing a first embodiment of the present invention.

FIG. 6 is an explanatory view of a teaching jig showing a second embodiment of the present invention.

FIG. 7 is an explanatory view of a teaching jig showing a third embodiment of the present invention.

FIG. 8 is an explanatory view of a teaching jig showing a fourth embodiment of the present invention.

FIG. 9 is an explanatory view of a sensor jig used for carrying out the present invention.

FIG. 10 is an explanatory diagram of a wafer position teaching method according to the present invention.

FIG. 11 is an explanatory diagram of a wafer position teaching method according to the present invention.

FIG. 12 is an explanatory diagram of a wafer position teaching method according to the present invention.

FIG. 13 is an explanatory diagram of a wafer position teaching method according to the present invention.

FIG. 14 is a flowchart showing a wafer position teaching method according to the present invention.

Explanation of reference numerals [0008] 1 robot, 2 columns, 3 1st arm, 4 2nd arm, 5 wafer gripper, 6 transmitted light sensor, 7 robot rotation center, 8 light emitting section, 9 light receiving section, 10 optical axis, 11 teaching Jig, 12 large disc, 13 sensor jig, 14 sensor mount plate, 15 positioning hole, 16 notch for sensing, 17 second transmitted light sensor, 18 optical axis, 19 sensor cable, 20 positioning pin, 21 Sensor cable connector, 22 Small circular pin, 23 Teaching jig, 24 Teaching jig, 25 Teaching jig, 26 Arch shape part, 27 Fitting groove, 28 Fitting groove, 29 Wafer center point

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

Example 1

FIG. 1, FIG. 2 and FIG. 3 are explanatory views of a robot used for carrying out the present invention. FIG. 1 and FIG. 2 are plan views, and FIG. 3 is a side view. In the figure, 1 is a horizontal articulated robot for transferring semiconductor wafers, and W is a semiconductor wafer to be transferred by the robot 1. The robot 1 has a first arm 3 that rotates in a horizontal plane around a robot rotation center axis 7 of a column-shaped support portion 2 that can move up and down, and a first arm 3 that is rotatably mounted in a horizontal plane at the tip of the first arm 3. 2 includes an arm 4 and a wafer gripper 5 that is attached to the tip of the second arm 4 so as to be pivotable in a horizontal plane. The wafer gripper 5 is a Y-shaped hand on which the semiconductor wafer W is placed, and has a set of first transmitted light sensors 6 at the tip of the Y-shape.

As shown in FIGS. 1 to 3, the robot 1 moves the first arm 3 to the column 2 while maintaining the relative angles of the first arm 3, the second arm 4, and the wafer holding section 5. Rotate around the central axis 7 Θ Axis operation (rotation), the first arm 3, the second arm 4, and the wafer gripper 5 are rotated at a constant speed ratio, so that the wafer gripper 5 is supported by the support 2 It has three degrees of freedom: an R-axis operation (expansion / contraction) for expanding and contracting in the radial direction, and a Z-axis operation (elevation) for elevating and lowering the column 2. Here, the Θ-axis has a positive direction in the counterclockwise direction (see FIG. 1), and the R-axis has a positive direction in which the wafer gripper 5 is moved away from the column 2, that is, the direction in which the arm is extended (see FIG. 2). For the Z axis, the direction in which the column 2 is raised is plus (see FIG. 3).

FIG. 4 is an explanatory diagram of the transmitted light sensor 6. In the figure, reference numeral 8 denotes a light emitting unit attached to one end of a Y-shaped wafer gripping unit 5, and 9 denotes a light emitting unit 8 at the other end so as to face the light emitting unit 8. This is a light receiving unit attached to the device. The light emitting section 8 and the light receiving section 9 constitute a first transmitted light sensor 6. Reference numeral 10 denotes an optical axis directed from the light emitting unit 8 to the light receiving unit 9, and the first transmitted light sensor 6 can detect an object blocking the optical axis 10.

FIG. 5 is an explanatory view of a wafer gripper and a teaching jig showing the first embodiment of the present invention, (a) is a plan view of the wafer gripper, and (b) and (c) show the teachings. It is the top view and side view of a jig. In the figure, reference numeral 12 denotes a large disc portion of the teaching jig 11, and a diameter D of the large disc portion 12 is the same as that of the actual wafer. 22 is a small circular pin and 26 is an arch-shaped part. A position where the distance L1 from the center of the large disk portion 12 to the outer periphery of the arched portion 26 is the same as the distance L2 from the wafer center point 29 to the optical axis 10 when the wafer is gripped by the wafer gripper 5. Place arched part 26 on Since the teaching jig 11 has exactly the same outer diameter as the actual semiconductor wafer, the teaching jig 11 is correctly positioned by a positioning guide of a storage container or the like. Also, since the center of the circular arc on the outer periphery of the arch-shaped portion 26 of the teaching jig 12 and the large disc portion 12 coincide with each other and have the same radius, the rotation direction when the teaching jig 12 is installed may be slightly different. Deviations are allowed. In the present embodiment, the step 1 is about 123 mm, and the length of the outer peripheral arc of the arch-shaped portion 26 is designed to be about 55 mm, which corresponds to an angle of about 25 degrees. Therefore, the installation allowable angle in the rotation direction is about ± 12 degrees.

Example 2

FIG. 6 is an explanatory diagram of a teaching jig showing a second embodiment of the present invention. (A) is a plan view and (b) is a side view. The teaching jig 23 is characterized in that the diameter D of the large disc portion 12 is slightly larger than the diameter of the actual wafer. This is a type in which a recess with a diameter larger than the wafer is provided on the station side and the wafer is supported by dropping the wafer into the recess. The teaching is performed by adjusting the diameter of the teaching jig 23 to the diameter of the drop. It is intended to correctly set the jig 23. Actually, in a semiconductor wafer processing apparatus, a station called a load lock, which connects a front end portion and a process portion, is often a recessed type station.

Example 3

FIG. 7 is an explanatory view of a teaching jig showing a third embodiment of the present invention, wherein (a) is a plan view of the surface,

(b) is a plan view of the back surface, and (c) is a side view. The diameter D of this teaching jig 24 is It has the same diameter, a fitting groove 27 is formed on the back side to fit the support pin on the station side, and the teaching jig 24 is fitted on the support pin, so that the teaching jig 24 is correctly installed. It is intended. In fact, there are many stations in a semiconductor wafer processing apparatus that hold a wafer with three support pins.

Example 4

FIG. 8 is an explanatory view of a teaching jig showing a fourth embodiment of the present invention, wherein (a) is a plan view of the surface,

(b) is a plan view of the back surface, and (c) is a side view. The diameter D of the teaching jig 25 is the same as the diameter of the actual wafer, and a circular fitting groove 28 having the same central axis of the large disk portion 12 is formed on the back side to support the station side. It is intended that the teaching jig 25 be correctly installed by aligning the fitting groove 28 of the teaching jig 25 with the base (cylindrical). In fact, in many semiconductor wafer processing apparatuses, a device called a briar liner that detects the notch direction of a wafer or the like is designed to hold the wafer on a cylindrical pedestal.

FIG. 9 is an explanatory diagram of a sensor jig used for implementing the present invention. The sensor jig 13 includes a sensor mount plate 14, a second transmitted light sensor 17, and a sensor cable 19. The sensor mount plate 14 is a flat plate in which a part of a circular plate is cut out in a V-shape, and has four positioning holes 15. The positioning hole 15 is a guide hole that fits with a positioning pin 20 of the wafer gripping portion 5 described later to accurately position the sensor jig 13 on the wafer gripping portion 5. The V-shaped notch described above is a notch 16 for sensing, and when the sensor jig 13 is attached to the wafer gripper 5, the optical axis 10 of the first transmitted light sensor 6 of the wafer gripper 5 and the sensor mount Notches for avoiding interference of the plate 14 and for avoiding interference between a small circular pin of a teaching jig described later and the sensor mount plate 14. Reference numeral 17 denotes a second transmitted light sensor, which is fixed to the center of the sensor mount plate 14. Reference numeral 18 denotes an optical axis of the second transmitted light sensor 17. The second transmitted light sensor has a substantially U shape, and the width of the opening, that is, the length of the optical axis 18 is about 13 mm. Since the second transmitted light sensor 17 is fixed to the center of the sensor mount plate 14, when the sensor jig 13 is mounted on the robot hand, the second transmitted light sensor 17 is positioned substantially at the center of the semiconductor wafer mounting portion of the robot hand. 2 The transmitted light sensor 17 is located. Reference numeral 19 denotes a sensor cable for transmitting the signal of the second transmitted light sensor 17 to a robot controller (not shown). Next, a wafer position teaching method using these teaching jigs will be described. 10 to 13 are explanatory views of the wafer position teaching method according to the present invention, wherein (a) is a plan view and (b) is a side view. The figure shows a state where the sensor jig 13 is attached to the robot wafer gripper 5 and is brought close to the teaching jig 11. The positioning pin 20 is a guide pin that fits into a positioning hole (not shown in the figure) of the sensor mount plate 14 to correctly position the sensor jig 13 on the robot wafer gripper 5. The sensor cable connector 21 is a connector for connecting the sensor cable 19.

The optical axis 10 of the first transmitted light type sensor 6 fixed to the robot wafer gripper 5 is orthogonal to the length axis of the robot wafer gripper 5, but is fixed to a sensor jig. The optical axis 18 of the second transmitted light sensor 17 is mounted parallel to the length axis. That is, the optical axis 10 and the optical axis 18 are orthogonal. As described above, the teaching jig 11 has an arch-shaped portion 26 having a central axis common to the small circular pin 22 and the large disk portion 12 at the center of the large disk portion 12 having the same diameter as the actual semiconductor wafer. The large disk portion 12 can be placed at a place where a semiconductor wafer is placed, such as a storage container. The diameter of the small circular pin 22 is about 3 mm. The size of this diameter is determined so as to have a sufficient margin for the width of the opening of the second transmitted light sensor 17 of 13 mm. The length of the arc of the outer periphery of the arch-shaped portion 26 is about 55 mm. This length is determined so that there is enough room for the width of the opening of the sensor mount plate 14 to be 126 mm. Since the relative positions of the large disk portion 12 and the small circular pin 22 are measured in advance, the position of the large disk portion 12 can be known by knowing the position of the small circular pin 22. The thickness of the large disk portion 12 is about 2 mm, and the force of the actual semiconductor wafer is larger than 0.7 mm. This force is determined by the constraint on strength. Needless to say, it is better to be the same.

FIG. 14 is a flowchart showing a position teaching method according to the present invention. Hereinafter, this position notification method will be described step by step.

(Step 1) The sensor jig 13 is mounted on the wafer gripper 5 of the robot. At this time, use the positioning pin hole 15 and the positioning pin 20 to mount both positions accurately. Also connect sensor cable 19 to connector 21.

(Step 2) Check the displacement of the teaching jig 11 or the teaching jigs 23, 24, 25 by half It is placed on the place where the conductor wafer is placed. The selection of the teaching jig shall be selected according to the shape of the wafer installation surface on the station side. In the present embodiment, the teaching jig 11 will be described below. Since the large disk portion 12 of the teaching jig 11 has exactly the same outer diameter as the actual semiconductor wafer, the teaching jig 11 is correctly positioned by a positioning guide of a storage container or the like.

(Step 3) As shown in FIG. 11, the wafer gripper 5 is moved below the large disk part 12 by the operation of the operator.

(Step 4) The wafer gripper 5 is lifted, the lower surface of the large disc 12 is detected by the first transmitted light sensor 6, and the coordinate value Z on the Z axis of the robot at that time is recorded. In addition, the wafer gripper 5

1

Then, the upper surface of the large disk portion 12 is detected by the first transmitted light sensor 6, and the coordinate value Z of the Z axis of the robot at that time is recorded.

2

(Step 5) The wafer gripper 5 is moved onto the large disc 12. In other words, the height is set so that the first transmitted light sensor 6 can detect the small circular pin 22 when the wafer gripper 5 is advanced (here, the advance refers to the + direction of the R axis).

(Step 6) While the first transmitted light sensor 6 does not detect the small circular pin 22, the wafer gripper 5 is retracted to the position.

(Step 7) Operate the Θ axis to change the direction of the wafer gripper 5, and then operate the R axis to move the wafer gripper 5 forward and slowly approach the small circular pin 22, Record the coordinates of the Θ axis and the R axis when the first transmitted light sensor 6 first detects the small circular pin 22 (that is, when the optical axis 10 contacts the circumference of the small circular pin 22).

(Step 8) Steps 6 and 7 are repeated to bring the wafer gripper 5 closer to the small circular pin 22 with a different directional force, and the Θ axis when the optical axis 10 contacts the circumference of the small circular pin 22 The center position (0, Rs) of the small circle pin 22 is obtained and recorded by solving multiple least-squares methods of these values.

s

(Step 9) Based on the position of the small circular pin 22 obtained in Step 8, the 0-axis and the R-axis are operated to move the wafer gripper 5 to the position shown in FIG. Since the dimensions of the sensor mount plate 14, its notch 16 for sensing, and the second transmitted light sensor 17 have been measured in advance, the interference with the small circular pin 22 and the arch-shaped portion 26 is avoided, as shown in FIG. Hold the wafer to the position shown Part 5 can be moved.

(Step 10) By operating the Θ axis, the optical axis 18 of the second transmitted light sensor 17 is slowly brought close to the small circular pin 22, and the second transmitted light sensor 17 first moves the small circular pin 22 The coordinate value の of the Θ axis at the time of detection (that is, the optical axis 18 contacts the right side surface of the small circular pin 22) is recorded. Then the second

1

When the transmitted light sensor 17 stops detecting the small circular pin 22 (that is, when the optical axis 18 is separated from the left side surface of the small circular pin 22), the 値 axis coordinate value Θ is recorded. (0 + 0) Estimating the Z2 を axis

2 1 2

Update as value 0.

S

(Step 11) The Θ axis is operated at Θ stored in step 10. Next, as shown in Figure 13.

S

Then, the wafer gripper 5 is retracted to a position where the first transmitted light sensor 6 detects the arch-shaped portion 26. By operating the R-axis, the optical axis 10 of the first transmitted light sensor 6 is slowly moved away from the arched portion 26, and the first transmitted light sensor 6 no longer detects the arched portion 26 (i.e., Record the coordinate value Rt of the R axis when the axis 10 is also apart from the outer peripheral force of the arched portion 26).

(Step 12) The estimated position of the small circle pin 22 is calculated from Z and Z stored in Step 4 (Z + Z).

1 2 1 2 Z

Let 2 be the estimated value for the Z axis, use Rt found in step 11 as the estimated value for the R axis, and save Θ stored in step 10 as the estimated value for the Θ axis. Relative position of small circle pin 22 and large disk part 12

S

Since the positional relationship is measured in advance, if the position is shifted by this positional relationship,

Then, the position of the semiconductor wafer placed on the large disk portion 12, that is, the storage container or the like is determined, and this value is stored in the controller as the teaching position of the corresponding station.

(Step 13) If there are a plurality of teaching stations, steps 2-12 are repeated. In addition, if the teaching jigs are prepared for the number of stations and the teaching jigs are installed in all the stations in step 2, the steps 3-12 need only be repeated.

(Step 14) The sensor jig 13 is removed from the wafer gripper 5 of the robot.

(Step 15) Since the teaching position of each station has been determined in Step 12, the robot automatically collects all the teaching jigs based on the information in the same manner as when a normal wafer is transferred. . For example, the recovery means that the teaching jigs are transported to different slots of the cassette station without interfering with each other, and the teaching jigs stored in the cassette are stored in the cassette station. It is to take out ingredients all at once. If the operations from step 3 to step 15 are programmed in advance, the teaching of the position of the semiconductor wafer can be performed automatically without depending on the operation of the operator. However, it also includes operations that require some manpower, such as the operations in steps 3 and 14. In step 3, instead of manual operation, if the teaching position from the device drawing is input to the controller in advance, the starting point of step 3 is automatically determined for the value, and the robot arm is automatically moved to that position It is also possible to make it.

The derivation of (Θ, Rs) by the method of least squares in step 8 was performed by the inventor of the present application.

S

It was disclosed in detail in Contribution 1, so it was helpful! / ,.

Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is useful as a teaching jig for teaching a position of a semiconductor wafer to a semiconductor wafer transport robot.

Claims

The scope of the claims

[1] A teaching jig for teaching a position of a transfer target wafer to a robot for transferring a semiconductor wafer, wherein the teaching jig is placed at a place where the wafer is placed instead of the transfer target wafer. In a teaching jig for teaching the robot the position of the wafer by detecting a detected portion provided on the jig by a transmitted light type sensor provided on the hand of the robot,

A large disk portion having the same outer diameter as the wafer, a small circular pin having a central axis common to the large disk portion, and an arch-shaped object having a central axis common to the large disk portion; A center force of the large disc portion, a distance to the outer circle portion of the arch-shaped object, and an optical axis force of the sensor; and a distance to a center of the wafer mounting portion of the hand. Utensils.

2. The teaching jig according to claim 1, wherein the teaching jig has a groove on a rear surface thereof for fitting with a wafer support pin of a processing apparatus.

[3] The teaching jig according to claim 1, wherein the teaching jig can be gripped by the hand in the same manner as the transfer target.