Manufacturing system error detection
Method for detecting malfunction in photolithographic fabrication track Patent #: 6051348
ApplicationNo. 09/346632 filed on 07/01/1999
US Classes:438/14, WITH MEASURING OR TESTING382/144, Mask inspection (e.g., semiconductor photomask)382/145, Inspection of semiconductor device or printed circuit board382/149, Fault or defect detection382/151, Alignment, registration, or position determination430/30INCLUDING CONTROL FEATURE RESPONSIVE TO A TEST OR MEASUREMENT
ExaminersPrimary: Niebling, John F.
Assistant: Luk, Olivia
Attorney, Agent or Firm
International ClassH01L 23/544 (20060101)
AbstractAn adjustment error in a photolithographic stepping printer is detected by applying photoresist to a semiconductor wafer, and exposing the wafer to substantially identical light images in multiple locations using a stepping printer. The light images are defined by an optical reticle and include a plurality of lines or other features that are spaced from each other at approximately the resolution limit of the printer. Developer (16) is applied to the wafer to produce visible images corresponding to the light images. The visible images function as diffraction gratings which reflect light from the wafer. The visible images are inspected optoelectronically or manually. An adjustment error is determined to exist if the visible images appear substantially identical but are uneven or otherwise abnormal.