Chemical vapor deposition of copper metal using copper(hexafluoroacetylacetonate)(2) alcohol adducts.

摘要

A series of alcohol adducts of Cu(hfac)2 (Cu(hfac)2·ROH, where hfac- = hexafluoroacetylacetonate and ROH = C1, C2, C3, C4 alcohols) were synthesized as precursors for CVD of Cu metal. The low melting points of some Cu(hfac)2·ROH adducts allowed them to be used as liquid precursors at the common precursor evaporation temperature (ca. 80°C). Metallic Cu films were obtained using most of these compounds as precursors under either H2 or N2 mixed with the corresponding alcohol vapor. The details of each CVD reaction were studied by IR analysis of byproducts and electrical and thickness measurements on the resulting films. A reaction scheme is proposed in which the alcohol acts as a reducing agent in the deposition of the Cu film.; Cu(hfac)2·i-PrOH was identified as the most effective precursor for Cu CVD. An average growth rate of 1.3 +/- 0.5 mum/hr was obtained for the films deposited using CU(hfac)2· i-PrOH + i-PrOH(g) + N2. This growth rate is almost three times greater than that using Cu(hfac) 2 + H2 (the best Cu(II) precursor previously known), under similar deposition conditions.; CVD experiments were also performed using Cu(hfac)2· i-PrOH + i-PrOH(g) + (N2 or H2) on TiN or Pd-treated TiN surfaces. No continuous Cu films were deposited on either of these surfaces under N2, but films were obtained under H2. The Cu films showed faster and more uniform growth on PVD TiN than on CVD TiN substrates. The addition of i-PrOH increased the growth rate of Cu films on PVD TiN surfaces under H2 (from 0.26 +/- 0.04 mum/hr to 0.8 +/- 0.3 mum/hr). The films deposited with i-PrOH also showed improved adhesion to the PVD TiN surface, as compared with those obtained in the absence of the alcohol. Pre-treatment of TiN surface using Pd also led to somewhat improved film adhesion. However, the films deposited on such pre-treated substrates showed a higher resistivity than those deposited on clean TiN. Appropriate cleaning of the substrate was also critical for the deposition of good Cu films using Cu(hfac) 2·i-PrOH + i-PrOH( g) + H2 on PVD TiN substrates.