Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
Method and apparatus for determining the center and orientation of a wafer-like object










Image Number 3 for United States Patent #5822213.

A device and method for determining the center and orientation of a circular workpiece such as a semiconductor wafer. A laser diode projects a sheet of light onto a linear array of charge coupled devices which measures light intensity as a semiconductor wafer is rotated with its outer periphery intersected by the sheet of light. From a plot of light intensity data versus position at the wafer edge, a derivative of such plot can be calculated to locate an orientation notch or flat in the edge of the wafer. Also, from the plot of light intensity versus edge position it is possible to locate the center of the wafer relative to a rotation axis of a spindle on which the wafer is supported.








 
 
  Recently Added Patents
Substituted thiophene pentamers
Method for editing a media clip in a mobile terminal device, a terminal device utilizing the method and program means for implementing the method
Flash drive
Compositions and methods for concentrating and depleting microorganisms
Low drop-out regulator providing constant current and maximum voltage limit
Repeating frame battery with joining of cell tabs via welded-on male and female slip-fit connectors
Cineole
  Randomly Featured Patents
Annular solid immersion lenses and methods of making them
Baby seat
Skateboard shelf
Pyroelectric infrared sensor with different sized effective light receiving electrode areas and a method of manufacturing a dual pyroelectric element used therein
Knife hilt
Pallet and pallet runner of corrugated cardboard
Method and equipment for conditioning low-metal plastic scrap
Toy platform
Calorimeter
Power steering device for parking