Wafer transfer robot

TLDR: In this article, the authors presented an apparatus for transferring wafers to or from a wafer cassette having a plurality of wafer-receiving slots, wherein the apparatus consisted of a Wafer paddle which was adapted to be inserted into a waf cassette alongside the wafer.

Abstract: In one aspect, the present invention provides an apparatus for transferring wafers to or from a wafer cassette having a plurality of wafer-receiving slots, wherein the apparatus comprises a wafer paddle which is adapted to be inserted into a wafer cassette alongside a wafer. Edge grippers carried by the wafer paddle releasible grip the wafer by its edges. A first capacitive sensor carried by the wafer paddle is oriented in a first direction for sensing information about a wafer in a wafer receiving slot of the wafer cassette. A second capacitive sensor carried by the wafer paddle is oriented in a direction perpendicular to the first direction for sensing additional proximity information about a wafer in a wafer receiving slot of the cassette. A transport mechanism produces movement of the wafer paddle along at least three axes of movement to permit transferring wafers to or from respective wafer receiving slots of the wafer cassette. In a more specific aspect, the transport mechanism produces movement along five axes: relative translational movement along orthogonal x, y and z axes, rotational movement about a rotational axis, and tilting movement of the wafer paddle about a paddle tilt axis.