Substrate transferring device
A method for operating a substrate transferring device that includes a substrate container holding at least two substrates stacked vertically, a hand having two fingers, a manipulator, and a controller. A mapping device detects a vertical position of a higher substrate, and a substrate detector measures a distance to a principal surface of the substrate. The controller moves the hand to a position below the detected vertical position and then advances the hand to pick up the higher substrate. During forward movement, the substrate detector acquires at least three consecutive, linearly aligned distance measurements along a front-and-rear direction. Based on a relationship among the measurements, the controller determines whether the principal surface of the higher substrate is warped. If warpage is detected, the controller predicts a possibility of collision between the hand and the substrate and withdraws the hand to avoid collision.
1 . A method for operating a substrate transferring device, the substrate transferring device comprising:
a substrate container configured to hold at least two substrates stacked vertically;
a hand configured to hold one of the at least two substrates, the hand having two fingers;
a manipulator to which the hand is attached;
a controller configured to operate the manipulator in order to move the hand;
a substrate detector provided on at least one finger of the hand and comprising a light-emitter configured to continuously emit a light to a principal surface of the substrate and a light-receiver configured to receive the light reflected by the principal surface of the substrate, the substrate detector configured to determine a distance from the substrate detector to the principal surface;
a mapping device configured on at least one finger of the hand and comprising a light-emitter configured to emit light horizontally, and a light-sensor configured to receive the light from the light emitter, the mapping device configured to output positional information to the controller to indicate a vertical position of a substrate located in the substrate container;
the method being performed in a state in which a higher substrate is positioned above a lower substrate in the substrate container, the method comprising using the controller to:
(i) first, control the manipulator to move the hand to a predetermined distance h 1 below a vertical position of the higher substrate detected by the mapping device in order to carry the higher substrate,
(ii) second, control the manipulator to move the hand forward to a position to pick up the higher substrate, and
(iii) third, while the manipulator is moving the hand forward, the substrate detector measures the distance from the hand to the principal surface of the higher substrate at positions linearly continuing in a front-and-rear direction to take at least three consecutive and linearly aligned measurements: ha 5 , ha 6 , ha 7 ;
(iv) fourth, determine that the principal surface of the higher substrate is warped if ha 5 >ha 6 and ha 6 <ha 7 ;
wherein if the controller determines that the principal surface of the higher substrate is warped, the controller predicts based on the subsequent measurements from the substrate detector whether the hand may collide with the higher substrate, and the controller controls the manipulator to withdraw the hand as a result of the controller predicting that collision is possible because the principal surface of the higher substrate is warped.
2 . The method for operating the substrate transferring device according to the claim 1 , wherein the substrate transferring device further comprising a light-emitter emitting upwardly the light and the light-receiver receiving downwardly.
3 . The method for operating the substrate transferring device according to the claim 1 , wherein if the controller determines that the distance to the principal surface is less than a predetermined limit, the hand is moved away from the principal surface so that the distance to the principal surface is at least the predetermined limit.
4 . A method for operating a substrate transferring device, the substrate transferring device comprising:
a substrate container configured to hold at least two substrates stacked vertically;
a hand configured to hold one of the at least two substrates, the hand having two fingers;
a manipulator to which the hand is attached;
a controller configured to operate the manipulator in order to move the hand;
a substrate detector provided on at least one finger of the hand and configured to detect whether a principal surface of the substrate is warped by taking measurements of a distance from the substrate detector to the principal surface;
a mapping device configured on at least one finger of the hand and comprising a light-emitter configured to emit light horizontally, and a light-sensor configured to receive the light from the light emitter, the mapping device configured to output positional information to the controller to indicate a vertical position of a substrate located in the substrate container; and
the method being performed in a state in which a higher substrate is positioned above a lower substrate in the substrate container, the method comprising using the controller to:
(i) first control the manipulator to move the hand to a predetermined distance h 1 below a vertical position of the higher substrate detected by the mapping device in order to carry the higher substrate,
(ii) second, control the manipulator to move the hand forward to a position to pick up the higher substrate, and
(iii) third, while the manipulator is moving the hand forward, the substrate detector is configured to measure the distance from the hand to the principal surface of the higher substrate at positions linearly continuing in a front-and-rear direction to take at least three consecutive and linearly aligned measurements: ha 5 , ha 6 , ha 7 ;
(iv) fourth, determine that the principal surface of the higher substrate is warped if ha 5 >ha 6 and ha 6 <ha 7 ;
wherein if the controller determines that the distance to the principal surface of the higher substrate is warped, the controller predicts based on the subsequent measurements from the substrate detector whether the hand may collide with the higher substrate, and the manipulator is configured to withdraw the hand as a result of predicting that collision is possible because the principal surface of the higher substrate is warped.
5 . The method for operating the substrate transferring device according to claim 4 , wherein
the substrate detector comprising a light-emitter to emit a light to the principal surface of the substrate and a light-receiver to receive the light reflected by the principal surface of the substrate.
6 . The method for operating the substrate transferring device according to the claim 4 , wherein the substrate transferring device further comprising a light-emitter emitting upwardly the light and the light-receiver receiving downwardly.
7 . The method for operating the substrate transferring device according to the claim 4 , wherein if the controller determines that the distance to the principal surface is less than a predetermined limit, the hand is moved away from the principal surface so that the distance to the principal surface is at least the predetermined limit.