Resources Contact Us Home
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
Graphical user interface for interpreting the results of image analysis
Substrate processing apparatus and display method of substrate processing apparatus
Block copolymer nanoparticle compositions
Social community generated answer system with collaboration constraints
Integrated circuit packaging system with laser hole and method of manufacture thereof
Method and apparatus for belling plastic pipe
  Randomly Featured Patents
Automated dual cooking surface grill and method
Device for cutting any width of wood or other materials
Absorbent article with wetness indicator
Module comprising IC memory stack dedicated to and structurally combined with an IC microprocessor chip
Image forming apparatus
Container neck finish and method and apparatus for forming same and cap for use thereon
Low silver halide radiographic film for dental care
Photoelectrochemical cell
Optical components and production thereof
Continuous metal casting plant with controlled band-tensioning