TIN ETCHING AND ITS EFFECTS ON TUNGSTEN ETCHING IN SF6 AR HELICON PLASMA/

Etching characteristics of TiN film have been investigated in SF6/Ar h elicon plasma. The etch rate of TiN film increases with increasing sou rce power, bias power and temperature, exhibits a maximum at a moderat e pressure as a function of pressure. A possible mechanism of titanium fluoride formation is proposed based on the results of optical emissi on spectroscopy (OES). In order to determine the effect of titanium fl uorides on tungsten etching, the loading effect in tungsten etchback i s investigated as a function of source power, bias power and temperatu re. Using secondary ion mass spectrometry (SIMS), the relative concent rations of titanium fluorides redeposited on tungsten are measured by varying the bias power and temperature. The loading effect is reduced by enhancing the redeposition of titanium fluorides on a tungsten plug with increasing source and bias power. The loading effect is also ret arded by lowering the temperature.