Reactive ion etching of tantalum in silicon tetrachloride

A precise patterning of metal structures plays an essential role in the development of feasible metal-based devices. By examining the etching conditions under which a layer of material is properly etched, the etching process can be further optimised and hence controlled. This work reports on the reactive ion etching (RIE) of micrometric films of tantalum (Ta) using silicon tetrachloride (SiCl4)/Argon (Ar) plasmas. The etching characteristics have been studied with respect to SiCl4/Ar ratio, plasma power and chamber pressure. It has been found that increasing the flow rate of SiCl4 or plasma power leads to an increase in the etching rate. Moreover, the observations suggest that it is ineffective to increase the flow rate of Ar to more than 30 sccm and the plasma pressure to more than 100 mTorr. The work implemented here represents an important step for the development of tantalum-based structures that can be used in a wide range of devices.