ROBOT AND SUBSTRATE ORIENTATION EXAMINATION METHOD

A robot that transfers a substrate includes a hand, an arm, a substrate detector, and a substrate orientation examiner. The hand holds and transfers the substrate. The arm is connected to the hand and moves the hand. The substrate detector detects absence or presence of the substrate in a non-contact manner. The substrate orientation examiner examines an orientation of the substrate based on a height detected by the substrate detector at which the substrate is located when it is not held by the hand.

TECHNICAL FIELD

The present disclosure chiefly relates to a robot that transfers substrates, such as semiconductor wafers and printed circuit boards. More particularly, the present disclosure relates to a configuration for detecting an orientation of a substrate to be transferred before holding it.

BACKGROUND ART

Conventionally, there has been a known robot for transferring a substrate that takes out a substrate from a substrate storage apparatus, a substrate processing apparatus, or the like, and transfers it. PTL 1 discloses a wafer transfer apparatus, which is a robot of this type.

The wafer transfer apparatus of PTL 1 includes an orientation detector that detects an orientation of a hand and an actuator. In this wafer transfer apparatus, the orientation of the hand is adjusted by controlling a degree of expansion and contraction of the actuator based on information of the orientation of the hand detected by the orientation detector.

Patent Documents

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

The orientation detector of PTL 1 only detects the orientation of the hand and cannot detect an orientation of a substrate before it is held by the hand. If the orientation of the substrate is not appropriate, the substrate may be damaged during the process of being held by the robot.

The present disclosure is made in view of the situation described above, and its purpose is to accurately detect an orientation of a substrate to be transferred before a robot takes out the substrate and holds it.

Means for Solving the Problems

The problem to be solved by the present disclosure is as described above. The means to solve this problem and the effects thereof will be described below.

A first aspect of the present disclosure provides a robot with a configuration described below. That is, a robot that transfers a substrate includes an arm, a hand, a substrate detector, and a substrate orientation examiner. The hand is installed to the arm and holds and transfers the substrate. The substrate detector detects absence or presence of the substrate in a non-contact manner. The substrate orientation examiner examines an orientation of the substrate based on height information detected by the substrate detector about a height at which the substrate is located when it is not held by the hand.

A second aspect of the present disclosure provides a substrate orientation examination method as follows. That is, in the substrate orientation examination method, a robot that transfers the substrate examines the orientation of the substrate. The robot includes an arm, a hand, and a substrate detector. The hand is installed to the arm and holds and transfers the substrate. The substrate detector detects absence or presence of the substrate in a non-contact manner. The orientation of the substrate is examined based on height information detected by the substrate detector about a height at which the substrate is located when it is not held by the hand.

In these manner, an examination of the orientation of the substrate can be made before it is took out from a substrate storage apparatus or the like. Therefore, when the hand moves, unintended contact between the hand and the substrate that occurs due to an inappropriate orientation of the substrate can be avoided. As a result, the substrate can be prevented from, for example, being damaged.

Effects of the Invention

According to the present disclosure, the orientation of the substrate to be transferred can be accurately detected before the robot takes out the substrate and holds it.

EMBODIMENT FOR CARRYING OUT THE INVENTION

The disclosed embodiments will be described below with reference to the drawings.FIG.1is a perspective view showing an overall configuration of a robot100according to one embodiment of the present disclosure.

The robot100shown inFIG.1is installed, for example, in a plant for the manufacture of a substrate W, such as a semiconductor wafer or a printed circuit board, or in a warehouse for storing the substrate W. The robot100is used to transfer the substrate W between a substrate processing apparatus and a substrate storage apparatus7which is described below. Note, however, that the robot100may also be used, for example, to transfer the substrate W between multiple substrate processing apparatuses that process the substrate W. The substrate W may be any of the following: a raw material for a substrate, a semi-finished product in process, or a finished product. The substrate W is disc-shaped in the present embodiment, but is not limited to this.

The robot100chiefly includes a base1, a robot arm (an arm)2, a robot hand (a hand)3, and a robot controller (a substrate orientation examiner)9.

The base1is fixed to a floor of a factory or the like. Note, however, that the base1may also be fixed, for example, to a casing of a substrate processing facility equipped with the aforementioned substrate processing apparatus, without limitation. The base1may also be fixed to a moving cart, which is not shown in the drawings, that travels between the substrate processing apparatus (or facility) and the substrate storage apparatus7.

As shown inFIG.1, the robot arm2is installed to the base1with a lifting shaft11that can move in the vertical direction installed between them. The robot arm2can rotate with respect to the lifting shaft11.

The robot arm2includes a horizontal articulated robot arm. The robot arm2includes a first arm21and a second arm22.

The first arm21is comprised of an elongated member extending in a horizontal direction. One end of the first arm21in the lengthwise direction is installed to the upper end of the lifting shaft11. The first arm21is rotatably supported to rotate around the (vertical) axis of the lifting shaft11. The second arm22is installed to the other end of the first arm21in the lengthwise direction.

The second arm22is comprised of an elongated member extending in a horizontal direction. One end of the second arm22in the lengthwise direction is installed to the distal end of the first arm21. The second arm22is rotatably supported to rotate about an (vertical) axis parallel to the lifting shaft11. The robot hand3is installed to the other end of the second arm22in the lengthwise direction.

Each of the lifting shaft11, the first arm21and the second arm22is driven by a suitable actuator, not shown in the drawings. These actuators may be, for example, electric motors.

Arm joints are located between the lifting shaft11and the first arm21, between the first arm21and the second arm22, and between the second arm22and the robot hand3. An encoder, not shown in the drawings, is installed at every arm joint and detects rotational position of each of the first arm21, the second arm22and the robot hand3. Also, at an appropriate location on the robot100, an encoder that detects changes in the position of the first arm21in the height direction (i.e., an amount of lift of the lifting shaft11) is installed.

Based on positional information of the first arm21, the second arm22, or the robot arm3including information about their rotational position or vertical position detected by the corresponding encoder, the robot controller9controls the operation of each of the electronic motors that drives one of the lifting shaft11, the first arm21, the second arm22, and the robot hand3. In the following description, the term “positional information” detected by the encoders shall mean a combination of positional information detected by each encoder that represents the pose of the robot100.

The robot hand3includes a wrist31and a hand body32, as shown inFIG.1.

The wrist31is attached to the distal end of the second arm22with a tilter4installed between them. The wrist31is rotatably supported to rotate about an (vertical) axis parallel to the lifting shaft11. Note, however, that the axis of rotation of the wrist31can be tilted with respect to a line parallel to the lifting shaft11by using the tilter4. The configuration of the tilter4is described in detail below. The wrist31is rotationally driven by a suitable actuator that is not shown in the drawings. This actuator may be, for example, an electric motor. The hand body32is connected to the wrist31. The wrist31and the hand body32may be provided as one integrally formed member.

The hand body32is a member that acts in order to hold the substrate W. The hand body32includes a plate-like member formed in a Y-shape (or a U-shape). One end portion of the hand body32which is not connected to the wrist31(in other words, the distal portion) is split in two. In the following description, each of the bifurcated portions may be referred to as a first finger32aand a second finger32b.

The first finger32aand the second finger32bare formed to be symmetrical with each other. As shown inFIG.4andFIG.5, a suitable distance is formed between the tips of the first finger32aand the second finger32b. This allows the edge of the substrate W to be positioned between the tips of the first finger32aand the second finger32bwithout the robot hand3coming into contact with the substrate W.

More than one guide member33for holding the substrate W is installed both on the distal portion and on the proximal portion of the hand body32of the present embodiment. The guide members33are comprised of, for example, rubber. The guide members33are installed to project upward from the hand body32, which is a plate-like member. For example, as shown inFIG.1, one guide member33is installed on each of the first finger32aand the second finger32b, and two guide members33are installed on the proximal end portion of the hand body32.

As shown inFIG.1, the guide members33contact portions of the bottom surface of the substrate W close to its rim and they hold the substrate W placed on the robot hand3. By contacting the rim of the substrate W from the outside of the substrate W in the radial direction, the guide members33regulate the substrate W placed on the robot hand3so that it does not slide in the horizontal direction.

The configuration of the robot hand3to hold the substrate W is not limited to the configuration described above. The robot hand3may hold the substrate W by, for example, a structure that suctions the top surface or the bottom surface of the substrate W with negative pressure. For example, the robot hand3may be equipped with a known Bernoulli chuck to hold the substrate W in a non-contact manner.

The tilter4is installed to the distal portion of the second arm22(to the end portion opposite to the other end portion connected to the first arm21).

The tilter4includes a bottom plate41and the top plate42as shown inFIG.2. The bottom plate41is fixed to the top surface of the second arm22. The top plate42rotatably supports the wrist31of the robot hand3. A height adjuster5is located between the bottom plate41and the top plate42. The tilter4adjusts the angle and direction of a tilt of the top plate42with respect to the bottom plate41by using this height adjuster5.

The height adjuster5includes, for example, three supports51,52,53arranged at different positions between the bottom plate41and the top plate42as shown inFIG.2. InFIG.3, the supports51,52, and53are drawn as they are positioned in a straight line for convenience of explanation, but in actuality, as shown inFIG.2, they are arranged to form a triangle in a plan view.

Each of the supports51and52includes an externally threaded member56, an internally threaded member57, and a spherical bearing58. The threaded shafts of the externally threaded members56are rotatably supported by the bottom plate41with their axes pointing in a vertical direction. Actuators (for example, electric motors), that are not shown in the drawings, can separately rotate each of these threaded shafts arranged in the two supports,51and52. Each of the internally threaded members57is coupled with the threaded shaft of the corresponding externally threaded member56. When the threaded shaft is rotated, the corresponding internally threaded member57moves in a vertical direction. This movement allows the height at which the supports51and52support the top plate42to be changed. The spherical bearings58are located between the internally threaded members57and the top plate42.

A spherical bearing58is arranged at the support53. The support53does not have such function to change the height of support by using threads.

With the electric motors driven, the supports51and52independently change the height of the top plate42with respect to the bottom plate41. In this manner, the angle and the direction of the tilt of the top plate42with respect to the bottom plate41are changed. As a result, the orientation (the angle and direction of the tilt) of the robot hand3with respect to the second arm22is adjusted. Note that, the configuration of the height adjuster5(and thus the tilter4) is not limited to this configuration described above.

The robot controller9stores results of detection made by the encoders corresponding to the orientation of the robot hand3as information about the orientation of the robot hand3. In this manner, the robot controller9can replicate the orientation of the robot hand3as memorized by controlling the electric motors that drive elements of the robot100(such as the lifting shaft11, the first arm21, the second arm22, and the robot hand3) in order to match results of detection made by the encoders that detect an orientation of the robot hand3to the stored information about the orientation of the robot hand3.

As shown inFIG.1, a mapping sensor (a substrate detector)6is arranged at the distal portion of the hand body32. The mapping sensor6allows a check of the presence or absence of the substrate W (that is, mapping) to be done in a non-contact manner. In the present embodiment, the mapping sensor6is comprised of, for example, a through-beam sensor including a light emitter61and a light receiver62. Without limitation, the mapping sensor6may also be comprised of, for example, a reflective sensor.

As shown inFIG.1and inFIG.4, the light emitter61is installed on the distal portion of the first finger32a. The light receiver62is installed on the distal portion of the second finger32b. The light emitter61emits a detection light toward the light receiver62. The detection light may be, for example, but not limited to, infrared light.

The light receiver62is connected to the robot controller9wirelessly or by wire. The light receiver62outputs an electrical signal to the robot controller9indicating whether or not the detection light is received. When there is no object (for example, the substrate W) between the light emitter61and the light receiver62, the detection light emitted from the light emitter61reaches the light receiver62and the light receiver62outputs an electrical signal indicating that the light is received. When there is an object between the light emitter61and the light receiver62, the detection light emitted from the light emitter61is blocked by the substrate W, and the light receiver62outputs an electrical signal indicating that the light is not received.

When a plurality of spaces for placing the substrate W are arranged at suitable intervals in the vertical direction in the substrate storage apparatus7, the robot controller9moves the robot hand3in the vertical direction across these spaces for placing, keeping the distal end of the robot hand3close to these spaces (mapping operation). At this time, the robot hand3is placed at such a position in a plan view that, when the substrate W is placed in the said space, the robot hand3is out of contact with the substrate W and the mapping sensor6can detect the substrate W. Based on the time-series data output from the mapping sensor6while the robot hand3is moved in the vertical direction, the presence or absence of the substrate W at each space for placing can be determined.

However, it is not limited to the above configuration. For example, when the robot hand3is moved in the vertical direction, the presence or absence of the substrate W may be determined corresponding to the positional information detected by the encoders, based on the output form the mapping sensor6corresponding to each position of the robot hand3. In this case, the information about the presence or absence of the substrate W obtained from the output of the mapping sensor6and the positional information detected by the encoders are associated with each other.

As long as the light receiver62can detect the light emitted from the light emitter61, the light emitter61and the light receiver62may be located any places of the robot hand3. For example, the light emitter61may be built into the first finger32aand the light receiver62may be built into the second finger32b.

As shown inFIG.1, the robot controller9is arranged separately from the base1. Note, however, that the robot controller9may be arranged inside the base1. The robot controller9is configured as a known computer and includes a processing unit, such as a microcontroller, a CPU, a MPU, a PLC, a DSP, an ASIC or a FPGA, a memory unit, such as a ROM, a RAM or a HDD, and a communication unit that can communicate with an external apparatus. The memory unit stores a program to be executed by the processing unit, various thresholds, data on the shape of the substrate W to be transferred, such as thickness and size, or the like. The communication unit is configured to transmit results of the detection made by various sensors (for example, the mapping sensor6and the encoders) to the external apparatus and to receive the information about the substrate W or the like from the external apparatus.

The examination of the orientation of the substrate W by the robot100of the present embodiment will be described in detail below with reference to the drawings fromFIG.4toFIG.6. The following description will be with reference to an example wherein an orientation of the substrate W stored in the substrate storage apparatus7is detected. In the following description, some configurations may be omitted in the drawings in order to illustrate each configuration of portions in a comprehensible way.

The substrate storage apparatus7shown inFIG.4is used to store the substrates W. In the substrate storage apparatus7, a plurality of substrates (for example, 100 or more substrates) are placed at regular intervals in the vertical direction (i.e., the heightwise direction of the substrate storage apparatus7) and stored.

In the substrate storage apparatus7, the substrates W are usually stored in horizontal poses. However, for some reason, such as deformation of a shelf or presence of a foreign substance, sometimes the substrate W is stored in the substrate storage apparatus7, having a non-horizontal orientation. The robot100of the present embodiment can examine the orientation of the substrate W (i.e., a tilt of the substrate W with respect to a horizontal plane or to the robot hand3) before taking the substrate W out from the substrate storage apparatus7and transferring it.

Although the substrate W can tilt three-dimensionally, in the present embodiment, a tilt of the substrate W with respect to a horizontal plane observed with a line of sight along the direction in which the robot hand3is inserted into the substrate storage apparatus7(hereinafter, this direction is referred to as the hand insertion direction) is examined. In other words, the target to be examined is a tilt of the substrate W in the roll direction with respect to the hand insertion direction.

Specifically, as shown inFIG.4, the robot controller9moves the robot hand3so that a portion of the substrate W to be examined is positioned between the first finger32aand the second finger32b, keeping the hand body32horizontal. At this time, the detection light emitted from the mapping sensor6is directed so as to be parallel to the suitable orientation of the substrate W.

Then, the robot controller9moves the lifting shaft11in the vertical direction to move the robot hand3in the vertical direction keeping it horizontal. As a result, a vertical scan is accomplished by the mapping sensor6. For example, as shown inFIG.5, the robot hand3moves from below to above or from above to below the substrate W. It is preferable to keep a speed of the movement of the robot hand3constant at this time in terms of ease of calculation of a detected thickness TH1which is described below.

When a portion of the substrate W passes between the first finger32aand the second finger32bof the robot hand3, the light emitted from the light emitter61is blocked by the substrate W. As a result, the output signal of the light receiver62changes, for example, as shown in the graphs inFIG.5.

The robot controller9calculates an interrupted time t0during which the light emitted from the light emitter61is interrupted by the substrate W while the robot hand3is moved in the vertical direction by analyzing time-series data which is based on the output of the light receiver62. The interrupted time t0can be referred to as a time of detection for which the mapping sensor6detects the presence of the substrate W. The robot controller9calculates a distance in which the robot hand3moves in the vertical direction during the calculated interrupted time t0and determine it as a detected thickness TH1of the substrate W to be examined. The detected thickness TH1corresponds to the difference between the maximum value and the minimum value of the heights at which the presence of the substrate W is detected (height information).

As shown inFIG.6, when the substrate W is placed horizontally with respect to the robot hand3, a distance in which the robot hand3moves during the light emitted from the light emitter61is interrupted equals an actual thickness TH of the substrate W. On the other hand, when the substrate W is tilted with respect to the robot hand3, a distance in which the robot hand3moves during the light emitted from the light emitter61is interrupted exceeds the actual thickness TH of the substrate W.

The robot controller9compares the detected thickness TH1of the substrate W calculated as described above with the actual thickness TH of the substrate W memorized by the memory unit and determines whether the substrate W to be examined is tilted or not using the above-described theory.

There are various method for the determination. For example, the determination may be made by comparing the difference between the detected thickness TH1and the actual thickness TH of the substrate W to be examined with the predetermined threshold. In this case, the robot controller9determines that the substrate W to be examined is tilted when the difference between them exceeds the threshold.

The actual thickness TH of the substrate W may be calculated in advance based on data, such as a design data and a manufacturing data of the substrate W. Also, an average thickness obtained by measuring more than one substrate W may be used as the actual thickness TH. The robot controller9receives the actual thickness TH obtained as described above from an external apparatus via the communication unit in advance and stores it in the memory unit.

When it is determined that the substrate W is tilted, the robot controller9performs appropriate control. Examples of the control may include excluding the substrate W concerned from targets to be transferred or stopping its operation. In this manner, the robot hand3does not insert itself into a space in the substrate storage apparatus7which corresponds to the substrate W that has an inappropriate orientation so that the substrate W and the robot hand3do not come into contact with each other and the substrate W is prevented from, for example, being damaged.

When a plurality of substrates W are arranged vertically, orientations of the substrates W may be examined with a single vertical movement of the robot hand3. It is preferable to obtain time-series data output by the mapping sensor6which is used to determine the presence or absence of the substrate W and to examine an orientation of the substrate W with a single vertical movement of the robot hand3in terms of reducing cycle time.

As described above, the robot100of the present embodiment is used to transfer the substrate W. The robot100includes the robot arm2, the robot hand3, the mapping sensor6, and the robot controller9. The robot hand3is installed to the robot arm2and holds and transfers the substrate W. The mapping sensor6detects the presence or absence of the substrate W in a non-contact manner. The robot controller9examines an orientation of the substrate W based on a height detected by the mapping sensor6at which the substrate W is located when it is not held by the robot hand3.

This allows an examination of the orientation of the substrate W to be made before the substrate W is taken out from an apparatus, such as the substrate storage apparatus7. Therefore, unintended contact between the robot hand3and the substrate W due to an inappropriate orientation of the substrate W is prevented from occurring while the robot hand3is moving. As a result, the substrate W is prevented from, for example, being damaged.

In the robot100of the present embodiment, the mapping sensor6is installed to the robot hand3. The robot controller9determines the maximum value and the minimum value of heights at which the presence of the substrate W is detected based on the output from the mapping sensor6while the robot hand3is vertically moved. The robot controller9examines the orientation of the substrate W based on the detected thickness TH1, which is the difference between the maximum value and the minimum value, and the actual thickness TH of the substrate W.

This allows an easy and accurate examination of the orientation of the substrate W with a simple configuration.

The robot100of the present embodiment is also equipped with the tilter4that tilts an orientation of the robot hand3in a desired direction.

This allows an orientation of the mapping sensor6, which serves as a basis for an examination of the orientation of the substrate W, to be adjusted with a great flexibility.

Next, a first variation of the embodiment described above will be explained below.FIG.7is a plan view illustrating an examination of a tilt of the substrate W in the first variation. In the description of the present variation, the same or similar components as that of the above-described embodiment may be marked with the same references in the drawings and the description thereof may be omitted.

The robot100of the present variation includes a rangefinder6xin addition to the mapping sensor6. The rangefinder6xand the mapping sensor6are comprised in the substrate detector. The rangefinder6xdetects a tilt of the substrate W with respect to a horizontal plane observed with a line of sight along the direction perpendicular to the hand insertion direction. In other words, the target to be examined by the rangefinder6xis a tilt of the substrate W in the pitch direction with respect to the hand insertion direction. In the present embodiment, results of the detection made by the rangefinder6xcorrespond to height information.

The rangefinder6xincludes, for example, a laser displacement meter or an ultrasonic distance sensor. The rangefinder6xis, as shown inFIG.7, for example, installed on the top surface of the second finger32bof the hand body32. The rangefinder6xdetects a vertical distance between the rangefinder6xitself and the bottom surface of the substrate W in a non-contact manner. The rangefinder6xis connected to the robot controller9wirelessly or by wire, and transmits data of the distance to the substrate W measured at the measurement position to the robot controller9.

The robot controller9inserts the robot hand3below the substrate W supported in the substrate storage apparatus7. In this manner, the rangefinder6xfaces the substrate W vertically. Note that the guide member33does not hold the substrate W at this time. By moving the robot hand3horizontally along the hand insertion direction, the robot controller9measures distances between the rangefinder6xand the substrate W to be examined at least at two points.

The robot controller9determines whether the substrate W is tilted with respect to a horizontal plane based on the difference of heights of the substrate W measured by the rangefinder6x.

When the substrate W is absent, the rangefinder6xmeasures an abnormal value. Therefore, the rangefinder6xcan be considered as a sensor that can substantially detect the presence or absence of the substrate W.

In the above-described embodiment, the mapping sensor6examines a tilt of the substrate W in the roll direction as observed with a line of sight along the hand insertion direction. In addition, in the present variation, the rangefinder6xexamines a tilt of the substrate W in the pitch direction. Thus, in the present variation, the tilt of the substrate W can be examined three-dimensionally.

As described above, in the robot100of the present variation, the rangefinder6xis installed to the hand body32in order to measure a vertical distance to the substrate W. The robot controller9examines an orientation of the substrate W based on each of the distances measured by the rangefinder6xat multiple points of the substrate W.

This allows an easy and accurate examination of the orientation of the substrate W with a simple configuration.

Next, a second variation of the above-described embodiment will be explained below.FIG.8is a plan view conceptually illustrating an examination of a tilt of the substrate W in the second variation. In the description of the present variation, the same or similar components as that of the above-described embodiment may be marked with the same references in the drawings and the description thereof may be omitted.

The robot100of the present variation includes only the mapping sensor6as the substrate detector. In other words, the robot100does not include the rangefinder6x.

As illustrated by the solid line inFIG.8, the robot100of the present variation obtains the detected thickness TH1by performing the same measurement as in the above-described embodiment, with the orientation of the detection light of the mapping sensor6in a plan view varied at each time. The tilt can be determined by comparing the detected thickness TH1with the actual thickness TH in the same way as described above. The choice of orientations of the detection light is not limited to the example shown inFIG.8. It can be changed variously.

In the present variation, the tilt of the substrate W can be three-dimensionally examined by using two detected thicknesses TH1.

Next, a third variation of the above-described embodiment will be explained below.FIG.9is a drawing conceptually illustrating an orientation of a detection axis of the mapping sensor6being changed in order to detect a tilt of the substrate W in the third variation. In the description of the present variation, the same or similar components as that of the above-described embodiment may be marked with the same references in the drawings and the description thereof may be omitted.

In the present variation, as shown inFIG.9, the robot controller9obtains the detected thickness TH1multiple times with the direction and magnitude of a tilt of the detection light of the mapping sensor6suitably varied at each time. Specifically, the robot controller9tilts the orientation of the detection light of the mapping sensor6in the roll direction by suitably tilting the robot hand3with respect to a horizontal plane. Then, the robot controller9moves the robot hand3up and down to obtain the detected thickness TH1corresponding to a titled orientation of the robot hand3.

After obtaining the multiple detected thicknesses TH1in this manner, the robot controller9determines an angular degree of a tilt of the detection light corresponding to one of the detected thicknesses TH1that is closest in value to the actual thickness TH. This angular degree of the tilt corresponds to a tilt angle θ of the substrate W in the roll direction. The tilt angle θ can be used as an indicator of how much the orientation of the substrate W deviates from the orientation that it should have.

As described above, in the robot100of the present variation, the robot controller9obtains the tilt angle θ that indicates the magnitude of the tilt of the substrate W, by making an examination while changing the orientation of the robot hand3by the tilter4.

This allows an orientation of the substrate W to be specifically detected.

While the preferred embodiment and the variations of the present disclosure have been described above, the configurations described above may be modified as follows, for example.

The detected thickness TH1may be determined based on results of detection made by the encoders (that is, positional information detected by the encoders) at times when the mapping sensor6starts outputting data indicating that no light is received and when it finishes outputting, instead of based on a vertical distance the robot hand3moves while the mapping sensor6is outputting data indicating that no light is received. In this case, the positional information detected by the encoders corresponds to the height information. In a case where the presence or absence of the substrate W is detected by the robot hand3moving up and down with its orientation maintained, the detected thickness TH1may be calculated by using results of the detection made only by the encoder that detects a positional change of the first arm21in the height direction (that is, the distance that the lifting shaft11moves).

The robot100may hold an object, such as a tray carrying the substrate W, instead of directly holding the substrate W to transfer.

The hand body32of the robot hand3may be integrally formed with the top plate42of the tilter4.

The tilter4may be arranged between the base1and the lifting shaft11, or between the lifting shaft11and the first arm21, or between the first arm21and the second arm22.

In the embodiment shown inFIG.5andFIG.6, the tilt angle θ of the substrate W may be calculated by somehow determining positions in a plan view at which the light emitter61and the light receiver62are located with respect to the substrate W. This calculation can be easily made by performing a geometric calculation based on the detected thickness TH1. The same applies to the variations shown inFIG.7andFIG.8.

In the first variation shown inFIG.7, the mapping sensor6may be omitted. In this case, the tilt of the substrate W in the pitch direction can still be examined by the rangefinder6xthat horizontally scans the substrate W along the hand insertion direction. Also, to examine the tilt of the substrate W, the rangefinder6xmay measure heights of three points on the substrate W that form a triangular shape in a plan view, with the robot hand3horizontally moved. In this case, the tilt of the substrate W can be three-dimensionally examined by using only the rangefinder6x.

In the robot hand3of the first variation, more than one rangefinder6xmay be arranged at different locations.

The orientation of the substrate W may be examined by an apparatus other than the robot controller9.

The functionality of the elements disclosed herein may be implemented using circuitry or processing circuitry which includes general purpose processors, special purpose processors, integrated circuits, ASICs (“Application Specific Integrated Circuits”), conventional circuitry and/or combinations thereof which are configured or programmed to perform the disclosed functionality. Processors are considered processing circuitry or circuitry as they include transistors and other circuitry therein. The processor may be a programmed processor which executes a program stored in a memory. In the disclosure, the circuitry, units, or means are hardware that carry out or are programmed to perform the recited functionality. The hardware may be any hardware disclosed herein or otherwise known which is programmed or configured to carry out the recited functionality. When the hardware is a processor which may be considered a type of circuitry, the circuitry, means, or units are a combination of hardware and software, the software being used to configure the hardware and/or processor.