Edge grip aligner with buffering capabilities

#1. Field of the Invention

#The present invention relates to semiconductor wafer handling and processing equipment, and in particular, to an edge grip device for reading an OCR mark on the wafer, wherein the device includes a buffer mechanism that allows a high throughput of wafers through the device.

#2. Description of the Related Art

#The present invention will now be described with reference to the drawings in which:

#FIG. 1 is a top perspective view of an aligner according to the present invention;

#FIG. 2 is a front side perspective view of an aligner according to the present invention with the housing and buffer support stand covers removed;

#The present invention will now be described with reference to FIGS. 1-7 which in preferred embodiments relates to an edge grip aligner with buffering capabilities. The aligner according to the present invention may be seated within a workpiece tool, such as for example a process tool, sorter or metrology tool. Alternatively, the aligner may be provided as a standalone unit. It is understood that the aligner according to the present invention may be configured to operate with various workpieces, and workpieces of various sizes.

#Referring to FIGS. 1-7, there is shown an edge grip aligner 100 according to the present invention including a chuck base 102, chuck arms 104, buffer support stand 134 and buffer arms 106a and 106b. Referring to FIGS. 2 and 3, the chuck base 102 is defined by a cylindrical housing 108 that encloses and protects the components within the chuck base (the housing is partially omitted from FIGS. 2 and 3 to show the internal components). The chuck base 102 further includes a top plate 110 mating with and affixed to a top portion of the housing 108. Top plate 110 includes a central hole 112 through which a mast 114 extends as explained hereinafter.

#The mast is mounted to a linear drive 118 for translating the mast 114 linearly along the Z-axis. In particular, linear drive 118 includes a carriage 120 through which the mast 114 is rotationally mounted, a lead screw 122 for vertically translating the carriage 120, and a motor 123 for rotating the lead screw 122. Additionally, a rail 124 is affixed to an interior surface of the housing, and the carriage is in turn translationally affixed to the rail 124. In a preferred embodiment, the linear drive motor is preferably comprised of a brushless multiple pole motor. Brushed motors are however contemplated in alternative embodiments. Referring to FIG. 2, torque from the motor 123 is transmitted to the lead screw via a pulley 125 on the lead screw, a pulley 127 on the output shaft of motor 123 and a belt 129 wrapped around the pulleys. It is understood that other torque transmission mechanisms may be used to transmit torque from the motor to the lead screw in alternative embodiments, including meshing gears and including a lead screw extending down into the motor, where is mounts directly to the armature of the motor. The motor further includes an encoder (not shown) for closed loop servo control of the motor rotation. In a preferred embodiment, the linear drive 118 is capable of translating the mast along the Z-axis approximately 1-2 inches, although it is understood the Z-axis stroke may be lesser or greater than that in alternative embodiments.