The stochastic nature of the IC fabrication process and the resulting difficulties in the process control are described. The multivariated statistical analysis （MSA） software package and its fundamental principles are presented. The data generated from 100 sets of test and for 23 parameters are analyzed with this MSA package. It shows that the MSA package is a powerful tool for analyzing the process data in IC production line. The relations between the process parameters and the device or circuit parameters from a great quantity of test data can be rapidly and accurately found out

and the key problems in fabrication process as well. It helps the technologists to make dicision on the optimization of fabrication process.