Combining Negative Binomial and Weibull Distributions for Yield and Reliability Prediction

摘要

A KEY PRODUCTIVITY METRIC in semiconductor manufacturing is wafer test yield--the fraction of dies deemed functional following wafer probe testing. Wafer test yield is directly related to semiconductor manufacturing profitability: The higher the yield, the lower the cost of producing a functional chip, and therefore the greater the potential profit. Because wafer test yield is such a critical variable in a product's profit potential, accurate yield projection models are essential to semiconductor manufacturers' economic success. Of course, once a product is shipped to the customer, the product's reliability, or continued functionality, becomes the main concern. In fact, ICs are usually built into larger systems, so an individual component's failure can result in the entire system's failure. Moreover, identifying and repairing a faulty system component is usually a difficult and costly task, so a large portion of a semiconductor manufacturer's customer satisfaction rating depends on product reliability.