ENHANCING THE ANALYSIS OF VARIANCE (ANOVA) TECHNIQUE WITH GRAPHICAL ANALYSIS AND ITS APPLICATION TO WAFER PROCESSING EQUIPMENT

One of the critical steps required to improve the overall quality of a wafer manufacturing operation is a reduction in the variability of th e individual processing operations. As a result, there is an increasin g need to quantify the capabilities of semiconductor manufacturing equ ipment. The goal should be to design a consistent method of monitoring equipment performance that samples the major sources of variation tha t can impact the process output. This paper discusses a statistical me thod that utilizes multi vari analysis and the analysis of variance to achieve this goal. The data presented is taken from a commercially av ailable silicon epitaxial reactor and FTIR film measurement tool, but the technique is generic and applicable to other wafer processing oper ations. The analysis method is presented along with some examples of t he application of the calculated standard deviation and process variat ion. In addition to determining the performance of a piece of equipmen t over time, this method of analysis can be used to specify and qualif y equipment. As an extension of this analysis it is possible to determ ine the contribution of the measurement system to the observed variabi lity in the process output.