半导体质量控制中的非正态工序能力指数计算模型

分析了目前几种主要的非正态工序能力指数计算模型,指出其适用范围和不足之处.根据数据的均值、标准偏差、偏度和峰度四个变量能够体现分布特性,结合切比雪夫-埃尔米特多项式,提出了新的非正态工序能力指数计算模型,该模型能克服数据偏差大时对计算结果的不良影响,并且其代数计算公式可以简化计算.实例分析结果准确有效.

Model of Non-Normal Process Capability Indices to Semiconductor Quality Control

It is necessary to compute the process capability index (PCI) of non-normal data when considering the level of semiconductor processes.Several main PCIs that have already been presented are analyzed,and their advantages and disadvantages are presented.Based on Chebyshev-Hermite polynomials,a model for computing non-normal PCIs is then given when regarding the fact that these four moments,i.e.mean,standard deviation,skewness,and kurtosis,are suitable to approximately characterize the data distribution properties,which is effective when data deviation is large.Finally,an example is given for proving the relational model.