Wafer orientation system

Apparatus for determining orientation of a wafer or the like, having a primary flat registration edge, along the wafer circumference, comprising:

• means for supporting a wafer,
• a first set of two rollers spaced apart at a distance less than the dimension of a primary flat registration edge, said two rollers radially inwardly biased against the wafer edge,
• a second set of rollers inwardly biased in a configuration defining circumferential contacts for a wafer circumferential edge within the configuration with said rollers in friction contact with the wafer edge,
• means for rotating the wafer within the configuration of the second set of rollers, and
• means for signalling coincident radial displacement in the same direction of the first set of rollers upon rotation of the wafer, said displacement of the first set of rollers indicating contact with a flat registration edge.

Apparatus for determining orientation of a wafer or the like, having a major flat registration edge along the wafer circumference comprising:

• a dual band conveyor for transporting wafers,
• a vertically movable bed supporting a first set of two rollers at changeable elevations above and below said conveyor, said two rollers spaced apart at a distance less than the dimension of a major flat registration edge, said two rollers radially inwardly biased against the wafer edge,
• a second set of rollers mounted for positioning at changeable elevations above and below said conveyor, said second set of rollers spaced in a configuration at the upper elevation defining a desired position for a wafer circumferential edge within the configuration with said rollers in friction contact with the wafer edge,
• means for rotating the wafer within the configuration of the second set of rollers at the upper elevation, and
• means for signalling coincident radially outward displacement of the first set of rollers upon rotation of the wafer, said outward displacement of the first set of rollers indicating contact with a flat registration edge.