Characterization of a PECVD W_XN Process Using N_2, H_2, and WF_6

摘要

A novel plasma-enhanced chemical vapor deposition (PECVD) Tungsten Nitride (W_XN) process was developed on an Applied Materials Centura~(TM) WxZ chamber. Nitrogen (N_2), Hydrogen (H_2), and Tungsten Hexafluoride (WF_6) are the active components for this PECVD process. Si substrate encroachment by WF_6 can be suppressed by a N_2/H_2 plasma pretreatment before W_xN deposition. Resistivity of W_xN film decreases as H_2/WF_6 ratio increases and deposition temperature rises. A metrology technique using ellipsometry was used to measure the index of refraction and absorption coefficient to quantify W_xN thickness and stoichiometry. Depending on W to N ratio and process conditions, the index of refraction, n, at 433 nm was measured between 3.26 and 3.68 and the absorption coefficient between 2.14 and 3.14. The resistivity of WxN with x=0.7-2.2 was measured between 1850 and 240 #mu##ation, the arcing temperature can be estimated. The copper metallization process is next generation semiconductor technoogy. Tantalum is good material to be the diffusion barrier layer. The structureational) IC Seminar November 5, 1998 TaipeiCPen1998TNInvestigation of Whisker Growth on