Application of non-parametric statistics of the parametric response for defect diagnosis

This paper presents a method using only the rank of the measurements to separate a part's elevated response to parametric tests from its non-elevated response. The effectiveness of the proposed method is verified on the 130nm ASIC. Good die responses are correlated for same parametric tests at different conditions such as temperature, voltage and or other stress. Nonparametric correlation methods are used to calculate the intra-die correlation. When intra-die correlation is found to be low the elevated vectors that lower correlation are extracted and input to IDDQ-based diagnostic tools. Monte-Carlo simulations are described to obtain confidence bounds of the correlation for good die test response.