Optimization of the Deposition Process Parameters of DC Magnetron Sputtering to Achieve Desired Deposition Rate Using Design of Experiment Method

In a DC magnetron sputtering system, the deposition rate is significantly affected by the sputtering power and working pressure, and the precise nature of this dependence varies from machine to machine. An understanding of the effect of sputtering parameters on the deposition rate is required before undertaking further studies. To do so, we have carried out a design of experiments study on the optimization of deposition process parameters using a Taguchi design methodology. Taking an example of silver (Ag) deposited on silicon (100) substrates using the DC magnetron sputtering method, we use a Taguchi L9 design to reduce the experimental design space from 27 to 9 combinations. The attributes of the Ag thin films were quantified with respect to surface roughness (Ra), thickness (t), and sheet resistance (R-s). The objectives of this study are 3-fold: establishing the effect of sputtering process parameters, namely the power and working pressure, on the deposition rate for the system under consideration; optimizing the sputtering process parameters within the chosen design space to ensure the formation of smooth conductive films using Taguchi analysis and response surface models; and analyzing the effect of annealing on the thin film characteristics. We found that the deposition rate increases with increasing the sputtering power. The highest deposition rate for the maximum power considered (25 W) was achieved at an intermediate working pressure of 6.1 x10(-3) mbar. The lowest deposition rate was obtained for the minimum power (5 W) and the highest working pressure (8.5 x 10(- 3) mbar) considered. For the given substrate-material system, we also found that the critical thickness below which the deposited films are non-conductive was 16 nm, which agrees with the existing literature.