Abstract: A method and arrangement for lifting lowering and centering a substrate on a surface employs lift pins have conical tips. A capture range is provided by the conical tips to capture and center misaligned wafers. One or more of the pins are inclined in certain embodiments to enhance the alignment capability of the lift pins. The inclined lift pins, when retracting into a support member at an angle, move a supported substrate horizontally into proper alignment.

Abstract: An apparatus for polishing a first side of a semiconductor wafer down to a desired level includes a polishing platen having a polishing surface. The polishing platen has a light egress opening defined therein. The apparatus also includes a wafer carrier which is configured to engage the wafer by a second side of the wafer and apply pressure to the wafer in order to press the wafer against the polishing surface of the polishing platen, wherein the wafer carrier has a light-ingress opening defined therein. The apparatus further includes an infrared light source unit positioned such that light signals generated by the infrared light source unit are directed out the light egress opening and into the wafer. The apparatus yet further includes a light receiving unit positioned such that the light signals generated by the infrared light source unit emanate out of the wafer and are received with the light receiving unit.