Prediction of parametric based on final test fallout using neighborhood analysis
It is desired to decrease time and money devoted to bum-in and to eliminate unnecessary processing of defective integrated circuits. Bum-in is a reliability screen used to isolate poorly performing integrated circuits before they complete testing and are shipped. A method is used to attempt to predict good and failing semiconductor devices at final test at an earlier stage in fabrication. Devices with a passing prediction may qualify for reduced bum-in. This method, neighborhood analysis, uses neighboring die on the semiconductor wafer on which it was made in order to predict whether it will pass or fail at final test, before it reaches bum-in. A correlation is investigated of final test failures against good units to identify whether or not a strong enough trend supports early scrapping of material, or a possible bum-in specification modification.