Data processing: generic control systems or specific application – Specific application – apparatus or process – Article handling
Reexamination Certificate
2001-04-25
2003-01-21
Tran, Khoi H. (Department: 3651)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Article handling
C700S218000, C700S037000, C700S250000, C700S254000, C700S258000, C318S568130, C318S568210, C414S805000, C414S806000, C414S936000, C901S003000, C901S005000
Reexamination Certificate
active
06510365
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method for positioning a conveying mechanism for conveying semiconductor wafers or the like, in particular to a method for quickly positioning a conveying system.
BACKGROUND OF THE INVENTION
In general, a system for manufacturing semiconductor devices includes combined various processing chambers. A conveying mechanism is provided between two of the chambers and/or between one of the chambers and a cassette for containing many semiconductor wafers, in order to convey the wafers automatically. The conveying mechanism has a conveying arm that is able to expand, contract, rotate and move vertically. The conveying arm is adapted to move horizontally to a predetermined convey-position in order to convey a wafer to a predetermined position.
In the case, it has to be avoided that the conveying arm interferes or collides with another element while the conveying arm is moving. In addition, the conveying arm has to appropriately receive a wafer that has been placed on a predetermined position, convey the wafer to an objective position and pass the wafer to an appropriate position precisely.
Thus, a “teaching operation” is performed. By the teaching operation, important positions such as a position in a moving path of the conveying arm to pass the wafer can be memorized as position coordinates in a controlling unit such as a computer that controls operations of the conveying arm.
SUMMARY OF THE INVENTION
The teaching operation is performed for almost all of positional relationships involved with receiving and passing of a wafer, such as a positional relationship between the conveying arm and a cassette container, a vertical positional relationship between the arm and the cassette for taking the wafer and a positional relationship between a stage of a load-lock chamber and the arm. Then, respective positional coordinates can be memorized. Each of driving systems incorporates an encoder or the like for determining a driving position thereof.
In detail, at first, a position in a moving path of the conveying arm is set as an absolute standard. Then, position coordinates are calculated from designed values with respect to positions in the entire system for which teaching operations should be performed. The calculated position coordinates are inputted into and memorized in the controlling unit as provisional position coordinates. In the case, the respective provisional position coordinates are inputted allowing for such a predetermined margin that the conveying arm does not collide with another element.
Next, the conveying arm is operated based on the respective provisional position coordinates. When the conveying arm reaches a vicinity of the teaching standard position, a control mode is switched into a manual mode. Then, for example in a state wherein a fork of the conveying arm and the wafer are in contact with each other, an operator performs a manual operation to make a center position of the fork coincide with a center position of the wafer while the operator watches the state from a lateral side with his or her naked eyes. After the centers coincide with each other, the coordinates are memorized in the controlling unit as accurate and appropriate position coordinates. The conventional teaching operation is performed according to the above steps. The teaching operations are performed manually and with operator's naked eyes for each of the teaching standard positions.
In the above conventional positioning method, the conveying arm is delicately positioned by made to rotate, expand and/or contract. Thus, there is a problem that the positioning needs very long time.
In addition, because of personal difference between the operators performing the teaching operations, accuracy of the positioning may be uneven. Furthermore, in a case wherein the fork and/or the arm is repaired or replaced, the above steps of positioning operation by teaching have to be repeated again, which may cause very long time loss.
This invention is intended to solve the above problems. The object of this invention is to provide a method for positioning a conveying system that can precisely and efficiently position a teaching standard position.
The invention is a method for positioning a conveying system including; a conveying arm having: a conveying arm body that is able to contract, expand, rotate and move vertically, and a holding portion provided at a tip portion of the conveying arm body for holding an object to be conveyed, a moving mechanism for causing the conveying arm to move, at least one container stage disposed in a moving area of the holding portion for placing a cassette container that can contain a plurality of objects to be conveyed in a tier-like manner, a direction-position positioning unit having: a rotation standard stage disposed in the moving area of the holding portion, and a position and posture detector for detecting an eccentric volume and an eccentric direction of the object to be conveyed placed on the rotation standard stage, and a controlling unit that can control entire operations, wherein the holding portion is positioned with respect to a standard position,
the method comprising; a step of inputting respective provisional position coordinates of an orienter teaching standard position that is a predetermined position on the rotation standard stage and a container teaching standard position that is a predetermined position in the cassette container placed on the container stage, into the controlling unit in advance, a step of conveying and placing an object to be conveyed precisely positioned with respect to and held by the holding portion onto the rotation standard stage, according to a control based on the provisional position coordinates of the orienter teaching standard position, a step of detecting an eccentric volume and an eccentric direction of the object to be conveyed placed on the rotation standard stage by the position and posture detector, a step of making appropriate position coordinates by amending the provisional position coordinates of the orienter teaching standard position based on the detected eccentric volume and the detected eccentric direction, a step of conveying and placing an object to be conveyed precisely positioned with respect to the container teaching standard position onto the rotation standard stage, according to a control based on the provisional position coordinates of the container teaching standard position, a step of detecting an eccentric volume and an eccentric direction of the object to be conveyed placed on the rotation standard stage by the position and posture detector, and a step of making appropriate position coordinates by amending the provisional position coordinates of the container teaching standard position based on the detected eccentric volume and the detected eccentric direction.
According to the feature, correct appropriate position coordinates can be obtained, by conveying an object to be conveyed manually precisely positioned with respect to and held by the holding portion of the conveying arm to the direction-position positioning unit or by taking an object to be conveyed manually precisely positioned with respect to each of the teaching standard positions by the conveying arm and conveying the object to the direction-position positioning unit by the conveying arm, and by detecting an eccentric volume and an eccentric direction of the object.
In a real operation, the controlling unit causes the conveying arm to move based on the appropriate position coordinates. Thus, the conveying arm can be positioned quickly and precisely without consuming long time like a conventional positioning. In addition, there is no personal difference in the positioning operation, that is, precise positioning can be always achieved not dependently on ability of the operator.
It is preferable that: the moving mechanism has a guide rail on which the conveying arm can slide, and the provisional position coordinates include an X-coordinate along the guide rail, an R-coordinate being a contraction or exp
Ishizawa Shigeru
Kawano Takashi
Nishinakayama Yasuhiko
Osawa Tetsu
Saeki Hiroaki
Smith , Gambrell & Russell, LLP
Tokyo Electron Limited
Tran Khoi H.
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