Textiles: weaving – Miscellaneous – Loom cleaning
Reexamination Certificate
1998-07-09
2001-05-15
Till, Terrence R. (Department: 1744)
Textiles: weaving
Miscellaneous
Loom cleaning
C134S006000, C015S088300, C015S102000
Reexamination Certificate
active
06230753
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to semiconductor processing and more particularly to a method and apparatus for cleaning wafers.
BACKGROUND OF THE INVENTION
Semiconductor manufacturing processes demand wafers, typically silicon wafers, which are substantially particulate free. As the semiconductor industry moves towards processing larger diameter wafers, for example 300 millimeter (mm) diameter wafers, it becomes increasingly difficult to remove particulates from the wafers. In particular, wafer cleaning processes must effectively remove particulates from the larger wafer surface area associated with the larger diameter wafers. Further, wafer cleaning processes must clean the wafers without exerting undue force on the wafers since larger diameter wafers have less mechanical strength than smaller diameter wafers.
SUMMARY OF THE INVENTION
In accordance with the present invention, a method and apparatus for cleaning a wafer oriented vertically is provided. In one embodiment, the apparatus includes a first brush and a second brush located horizontally from the first brush. The first brush and the second brush define a region between the brushes. Located vertically below the region defined by the first and second brushes, is a pair of rollers. During loading, a wafer is located vertically in the region between the first and second brushes and on the pair of rollers by a robotic arm.
The apparatus further includes a finger tip located vertically above the region defined by the first and second brushes. After the wafer is placed on the pair of rollers by the robotic arm, the finger tip is moved to contact an edge of the wafer and thus hold the wafer in the load/unload position. The robotic arm is then withdrawn from the apparatus.
The first and second brushes are then moved to contact the first and second wafer surfaces, i.e. are closed. The finger tip is then moved away from the edge of the wafer to release the wafer. The first brush, the second brush and wafer are then rotated while rinsing with a liquid to clean the wafer. After cleaning, the finger tip is again moved to contact the wafer edge and thus hold the wafer. The first and second brushes are then moved back away from the wafer, i.e. are opened. The robotic arm is again inserted into the apparatus to engage the wafer. The finger tip is then moved away from the edge of the wafer to release the wafer and the wafer is removed from the apparatus by the robotic arm.
In an alternative embodiment, instead of moving the finger tip away from the edge of the wafer to release the wafer and allow the wafer to rotate, the finger tip can be a V-grooved roller which is capable of rotating. In accordance with this alternative embodiment, the finger tip can remain in contact with the edge of the wafer while the wafer is rotated and cleaned.
In either embodiment, to reliably hold the wafer during loading/unloading, the pair of rollers and the finger tip have V-grooves and the wafer is securely held in the apexes of these V-grooves. Of importance, the wafer is held by the pair of roller and the finger tip at the precise load/unload position at which the robotic arm has been programmed to engage/disengage the wafer. Accordingly, the wafer is reliably and repeatedly engaged by the robotic arm reducing the average cycle time and manufacturing cost associated with wafer processing. Further, the apparatus is well suited for use with robotic arms having double or single armed end-effectors or edge grippers.
The apparatus may also clean the wafer edge in addition to the first and second surfaces of the wafer. In accordance with this embodiment, the finger tip can be a wafer scrubbing pad. By holding the wafer scrubbing pad against the wafer edge while the wafer is rotated during cleaning, the wafer scrubbing pad scrubs the wafer edge while the first and second brushes scrub the first and second wafer surfaces. In this manner, particulate removal from the wafer may be enhanced.
These and other objects, features and advantages of the present invention will be more readily apparent from the detailed description set forth below taken in conjunction with the accompanying drawings.
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Jones Oliver David
Vail Jim
Lam Research Corporation
Martine Penilla & Kim LLP
Till Terrence R.
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