| 摘要 |
PURPOSE:To conduct high speed and high quality sampling by binary codes for a picture signal obtained by scanning on a semiconductor pellet surface wherein thresholds are provided and counted to automatically detect inferior marks of pellets and the dimension of the areas. CONSTITUTION:A wafer cassette 2 is set on a base and photoelectric conversion 52, 56 is made for an image by illumination 36. The base is driven by a signal 62 for positioning 63. A binary codes 53, 54 are applied to a signal 52 to set different thresholds respectively. And a test mask is established 55 by a joy stick 56 and a monitor 57 to perform over and short judgement 60, 59 of pellet areas and inferior mark detection 58. A pick-up 48 is driven 61 based on the judgement to eliminate inferiority. In this composition, high speed and high quality sampling work will be performed continuously for many hours. |
