Wafer cleaning apparatus

Details Wafer cleaning apparatus Wafer cleaning apparatus

1999-11-15

2002-02-12

Till, Terrence R. (Department: 1744)

Brushing, scrubbing, and general cleaning

Machines

Wiping

C015S088300

Reexamination Certificate

active

06345404

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to semiconductor processing and more particularly to a an apparatus for cleaning waters.
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 12-inch diameter wafers, it becomes increasingly difficult to remove particulates from the wafers. In particular, water cleaning processes must effectively remove particulates from the larger water 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, an 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 use, a wafer in located vertically in the region between the first and second brushes and rests on the pair of rollers.
The apparatus further includes first and second brush positioners which move the first and second brushes, respectively, from first positions to second positions. In this manner, a wafer can be loaded and the first ad second brushes can be moved to contact surfaces of the wafer.
The first and second brushes are mounted on first ends of first and second shafts. Motors are connected to pulleys on the second ends of the first and second shafts. During use, the motors rotate the first and second shafts in opposite directions thereby rotating the first and second brushes in opposite directions. This forces the wafer into V-grooves in the pair of rollers. The wafer is then rotated by rotating the pair of rollers.
Preferably, the first and second shafts have central cavities formed therein and also have perforations in the regions where the first and second brushes are mounted. In this manner, liquid can be delivered to the first and second brushes though the first and second shafts to flush the first and second brushes from the inside out.
The wafer cleaning apparatus can further include first and send sets of spray nozzles capable of spraying a first liquid towards the wafer between the first and second brushes. The wafer cleaning apparatus can further include third and fourth sets of spray nozzles capable of spraying a second liquid towards the wafer between he first and second brushes. In one embodiment, the first liquid and the second liquid are the same liquid, and the liquid is a surfactant.
Alternatively, the first and second sets of spray nozzles can comprise first nozzles capable of spraying the first liquid and second nozzles capable of spraying the second liquid.
The combination of the scrubbing action on the wafer surfaces by the first and second brushes along with the liquid sprayed on the wafer surfaces from the first and second sets of spray nozzles remove particulates from the wafer surfaces. Since the wafer is oriented vertically, removal of particulates is enhanced since the liquid sprayed on to the wafer surfaces and the particulates trapped therein have a tendency to fall from the wafer surfaces due to gravity. This is particularly advantageous when cleaning larger diameter wafers, such as 8-inch or 12-inch diameter wafers, in which particulates must be removed from a larger surface area.
Further, by orienting the wafer vertically and by scrubbing both wafer surfaces simultaneously, mechanical stress on the wafer is minimized. This is particularly advantageous for larger diameter wafers which have less mechanical strength than smaller diameter wafers.
These and other objects, features and advantages of the present invention will be more readily apparent from the detailed description of the preferred embodiments set forth below taken in conjunction with the accompanying drawings.


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