Multiprobe blob test in lieu of 100% probe test

摘要

A method of predicting the effect of blob test in GSP sample testing is disclosed. The method includes extracting failure density maps from sample test results, where the density of any failed cell is expressed as the number of adjacent failing sample cells; determining the existence of local concentration of bad chips (blobs) as the occurrence of a detection density value above a threshold which can be adjusted to control the sensitivity of blob detection; determining the extent of such identified blobs as the occurrence of adjacent cells with density values above an inclusion threshold, which can be adjusted to control the sensitivity of blob extent determination; calculating a residual sample yield YNB for the areas outside blob regions using the total sample cell count NS, the passing cell count NG, and the count of cells in blobs NB by equation:and re-evaluating the decision of whether 100% probe test is required or if the cost savings can still be realized by performing only blob test.