Adaptive off tester screening method based on intrinsic die parametric measurements
AssigneeLSI Logic Corporation
InventorsManu Rehani, Kevin Cota, David Abercrombie, Robert Madge
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Abstract
A method for adaptively providing parametric limits to identify defective die quantizes the die into a plurality of groups according to statistical distributions, such as intrinsic speed in one embodiment. For each quantization level, an intrinsic distribution of the parameter is derived. Adaptive screening limits are then set as a function of the intrinsic distribution. Dies are then screened according to their parametric values with respect to the adaptive limits.
Claims18
A method of determining the disposition of a semiconductor die and controlling the level of stringency used in determining the disposition, the method comprising:
- measuring at least a first parameter for each of a plurality of dies, wherein the at least a first parameter includes at least one of the groups consisting of channel length, oxide thickness, current, and speed for the dies;
- quantizing the plurality of dies into a plurality of groups according to the values of the first measured parameter, the groups based on an upper limit and a lower limit for the first measured parameter;
- determining a statistical distribution for the dies in each of the plurality of groups;
- determining an intrinsic distribution function for the plurality of dies from the statistical distribution;
- setting an adaptive screening limit corresponding to the intrinsic distribution function;
- and
- identifying whether the die falls outside the adaptive screening limit.
Dependencies are inferred from the claim text.