AUTOMATED OPTICAL INSPECTION AND TEST OF ACTIVE-MATRIX LIQUID-CRYSTAL ARRAYS

Active matrix liquid-crystal displays (AMLCDs) are enjoying rapid market growth. But yields remain a major concern, and few AMLCD manufacturers are profitably producing these displays. One inspection technique, automated optical inspection (AOI), uses image processing methods to find defects in various patterned layers. AOI was originally created to find defects in photomasks, but it has been adopted for production of semiconductor wafers, printed circuit boards, multichip modules, and most recently, flat panel displays.