Semiconductor yield models using contagious distributions and their limiting forms

In order to set up a semiconductor yield model, one should consider defect density variations not only among chips but also within a chip. In this paper, we propose semiconductor yield models based on the contagious distributions reflecting the variations. These models incorporate the probability that a defect becomes fatal. We also consider various limiting forms of a proposed contagious distribution by taking extreme values of the related parameters. A simplified form of the proposed yield formula based on the limiting distribution is derived and its performance is compared with others using computer simulation. The proposed three yield models are shown in a simulation study to outperform alternative models based on the existing ideas.