Testing process capability for one-sided specification limit with application to the voltage level translator

摘要

Process capability indices C_(PU) and C_(PL) have been widely used in the microelectronics manufacturing industry as capability measures for processes with one-sided specification limits. In this paper, the theory of statistical hypothesis testing is implemented for normal processes, using the uniformly minimum variance unbiased estimators of C_(PU) and C_(PL). Efficient SAS computer programs are provided to calculate the critical values and the p-values required for making decisions. Useful critical values for some commonly used capability requirements are tabulated. Based on the test a simple but practical step-by-step procedure is developed for in-plant applications. An example on the voltage level translator manufacturing process is given to illustrate how the proposed procedure may be applied to test whether the process meets the preset capability requirement.