Tru-Si Technologies, Inc.

Igor Bagriy

Oleg Siniaguine

Sergey Savastiouk

Alex Berger

The present invention relates to a non-contact holder for substantially planar workpieces, particularly suited for holding thin workpieces without substantial distortion. The present invention includes a cylindrical chuck having a gas inlet orifice positioned at an oblique. The introduction of pressurized gas creates a vortex and vacuum attraction holding a wafer in close proximity to the chuck while the gas exiting from the chuck prevents contact between wafer and chuck. Small diameter chucks located in close proximity help the present invention avoid distortion when processing very thin workpieces. The gas exiting from the chuck of the present invention exits preferentially in a certain angular direction. Chucks are arranged on the wafer holder such that exiting gas is preferentially directed radially towards the periphery of the holder and that exiting gas is directed between adjacent chucks, not directly at another nearby chuck. Chucks on the periphery of the holder are positioned have the gas exiting therefrom towards the periphery of the holder and overlapping the gas flow from immediately adjacent chucks. Chucks on the periphery of the holder are located as close together as feasible. The combination of overlapping gas flow and close proximity creates a gas shield on the boundary of the wafer holder.

Non-contact workpiece holder

To move an article in and out of plasma during plasma processing, the article is rotated by a first drive around a first axis, and the first drive is itself rotated by a second drive, so that the article enters the plasma at different angles for different positions of the first axis. The plasma cross-section at the level at which the plasma contacts the article is such that those points on the article that move at a greater linear velocity (due to being farther from the first axis) move longer distances through the plasma. As a result, the plasma processing time becomes more uniform for different points on the article surface. The direction of rotation of the first and/or second drive changes during processing to improve processing uniformity. The article is allowed to be processed with the plasma only during one-half of each revolution of the second drive. In the other half of each revolution, the processing is substantially prevented by increasing the second drive velocity as the article is carried through the plasma.

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Sunnyvale, CA, United States of America

Igor Bagriy