The effect of defect clustering on yield of active-matrix LC-TV displays

Active matrix LC-TV (liquid-crystal television) displays are extremely sensitive to random defects arising during processing. These can cause electrical shorts or opens giving defective pixels or line defects. In seeking to model the yield of LC-TV displays, it is necessary to consider not only the overall defect density but also the spatial distribution of defects. It is shown that the degree to which defects are clustered can be modeled effectively using a Gamma distribution and that this provides in most cases a more accurate prediction of yield than when a nonclustered defect distribution is assumed. This situation is analogous to that experienced in the manufacture of integrated circuits, except that for LC displays additional information in the form of the number of pixel defects is available and can be used to determine the degree of clustering.<>