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
Tandem electric machine arrangement
Visual universal decryption apparatus and methods
Gaze tracking password input method and device utilizing the same
Method, system and computer program product for managing funds in custodial deposit accounts
Voltage regulators with improved wake-up response
Method and apparatus for focusing electrical stimulation in the brain during electro-convulsive therapy
Hard disk drives having different rotational speeds
  Randomly Featured Patents
Emulation suspension mode with frame controlled resource access
Apparel with reduced drag coefficient
Verification support apparatus, verification support method, and computer product
Lighter
Lenticular printing
Relevance clause for computed relevance messaging
Plunger system and method
Polishing composition
Ring applicator with an endoscope
Method of sending CTI messages in a communication system