Data processing: generic control systems or specific application – Specific application – apparatus or process – Article handling
Reexamination Certificate
1999-02-26
2001-05-22
Valenza, Joseph E. (Department: 3651)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Article handling
C901S009000, C414S331140, C414S331180, C414S937000
Reexamination Certificate
active
06236904
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
This invention relates to a substrate conveying system for conveying a substrate such as a semiconductor wafer or a liquid crystal plate, for example. More particularly, the invention is concerned with a substrate conveying system suitably usable in semiconductor manufacturing apparatuses such as a semiconductor exposure apparatuses, for example, for conveying a semiconductor wafer.
With increases in efficiency of semiconductor device manufacture, the size of a wafer to be used in a semiconductor exposure apparatus is being enlarged. As regards wafers to be used in such semiconductor exposure apparatus, the size has increased from conventional 6-inch wafer to 8-inch wafer and then to 12-inch wafer. Also, the size of conveying system for conveying wafers is being enlarged.
In the stream of enlargement in size of the wafer or wafer conveying system, problems such as flexure or distortion of wafer during conveyance have arisen from enlargement of wafer size. More specifically, when a large-size wafer is conveyed by using a conventional conveying system, flexure of the wafer itself may occur which, when the wafer is to be transported to a wafer carrier, for example, may cause interference between the edge of the wafer and the wafer carrier, resulting in breakage of the carrier or wafer. In order to avoid this problem, conventionally, the amount of wafer flexure is predicted and the wafer carrier is shifted vertically beforehand by an offset of an amount corresponding to the flexure of the wafer.
In this procedure, the wafer carrier is shifted vertically beforehand by an amount of offset corresponding to the amount of wafer flexure to thereby prevent interference. However, the wafer flexure is dispersive and, therefore, it is not easy to completely prevent interference between the wafer and the wafer carrier. Such interference may cause damage of the wafer or malfunction of the mechanism, resulting in breakdown of the apparatus. It needs repair work by an operator, which directly leads to a decrease of operation efficiency of the apparatus.
Similar problems may arise in apparatuses using substrates other than semiconductor wafers, such as liquid crystal plates for manufacture of liquid crystal display panels, for example.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a substrate conveying system by which, even if substrates such as semiconductor wafers or liquid crystal plates have dispersive flexure, they can be conveyed properly, by which malfunction of an apparatus or the need of repair work and maintenance load can be reduced, and by which the throughput and productivity of the apparatus can be enlarged.
In accordance with an aspect of the present invention, there is provided a substrate conveying system, comprising: a conveying mechanism for conveying a substrate; a sensor for producing positional information related to the substrate during conveyance of the substrate; and control means for controlling the substrate conveying operation on the basis of the produced information.
The substrate conveying operation may preferably be stopped in accordance with the information.
Said sensor may be serviceable to detect a maximum amount and a minimum amount of flexure of the substrate, and the substrate conveying operation may be stopped when a difference between these amounts becomes larger than a predetermined value.
The substrate conveying operation may be controlled in accordance with the information and data as specified by the operator.
The substrate conveying operation may be controlled in accordance with the information and data supplied from a superior host control means of said substrate conveying system.
Said control means may be operable to adjust relative positional relation between the substrate and substrate transfer means.
Said conveying mechanism may move the substrate in a lateral direction.
The substrate and the substrate transfer means may be relatively moved relative to each other, in a longitudinal direction, in accordance with the information.
The conveying mechanism may move the substrate in a longitudinal direction.
The substrate transfer means may be movable in a longitudinal direction.
The substrate transfer means may comprise a carrier for accommodating plural wafers therein.
The sensor may be disposed adjacent the substrate transfer means.
The sensor may be movable in a longitudinal direction.
The sensor may comprise a line sensor, or an optical sensor.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
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Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Tran Khoi H.
Valenza Joseph E.
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