This paper reports a study to optimize a process of fabricating conductive thin films using the Spray Pyrolysis Deposition Method. We are conducting the research on the multi-layer elements in our product. Two types of signal factors were studied. One type is to assess functionality and the other to assess manufacturability. A unique compounded noise factor was used, which resulted in a good reproducibility of conclusions. A gain of 14 decibels on SN ratio was accomplished. Also it became possible to vary sensitivity by 18 decibels without affecting S/N ratio.