Apparatus for inspecting a circuit pattern drawn on a photomask used in manufacturing large scale integrated circuits Patent #: 4559603
ApplicationNo. 06/786620 filed on 10/11/1985
US Classes:356/237.3, Detection of object or particle on surface716/21Pattern exposure
ExaminersPrimary: LaRoche, Eugene R.
Assistant: Pascal, Robert
Attorney, Agent or Firm
International ClassesG01N 21/88 (20060101)
G01N 21/94 (20060101)
AbstractA method and apparatus for particle detection and position correlation that fuses separate detections of the same particle on adjacent scan lines into one. A first scan line on a surface is scanned with a laser beam and the scattered light detected. The detection generates address and amplitude data for each particle which is stored. The second line scanned also generates data which is stored in a buffer. Particle data between scan lines is compared. Data for new particles is stored, data for previous particles no longer detected being sent to computer storage, and data for the same particle being compared and only the one with larger amplitude being kept. The results in computer storage may be displayed as a wafer with those pixels lit which have particles.