Yield estimation method for lsi

Abstract

Using data obtained by varying intra-chip variance, a frequency distribution of a yield corresponding to each intra-chip variance is obtained by a statistical timing analysis. The frequency of a ring oscillator loaded into the chip of an LSI is measured for each chip, and the frequency distribution of the ring oscillator is obtained. The convolution between the frequency distribution of a yield corresponding to each intra-chip variance and the frequency distribution of the ring oscillator is performed. By integrating the results the cumulative probability distribution of the yield of the LSI corresponding to each intra-chip variance is obtained. The fit is rendered between the distribution and the yield distribution of the LSI chip of the past lot, an appropriate intra-chip variance value is obtained, the cumulative probability distribution corresponding to the value is similarly calculated, and the result is defined as an estimated distribution of the yield of the LSI chip.