The effects of process conditions and substrate on copper MOCVD using liquid injection of (hfac)Cu(vtmos)

Copper MOCVD (metalorganic chemical vapor deposition) using liquid injectio n for effective delivery of the (hfac)Cu(vtmos) [1,1,1,5,5,5-hexafluoro-2,4 -pentadionato(vinyltrimethoxysilane) copper(I)] precursor has been performe d to clarify growth behavior of copper films onto TiN, <100> Si, and Si3N4 substrates. Especially, we have studied the influences of process condition s and the substrate on growth rates, impurities, microstructures, and elect rical characteristics of copper films. As the reactor pressure was increase d, the growth rate was governed by a pick-up rate of (hfac)Cu(vtmos) in the vaporizer. The apparent activation energy for copper growth over the surfa ce-reaction controlled regime from 155 degreesC to 225 degreesC was in the range 12.7-32.5 kcal/mol depending upon the substrate type. It revealed tha t H-2 addition at. 225 degreesC substrate temperature brought about a maxim um increase of about 25% in the growth rate compared to pure Ar as the carr ier gas. At moderate deposition temperatures, the degree of a <111> preferr ed orientation for the deposit was higher on the sequence of <Cu/Si<Cu/TiN< Cu/Si3N4. The relative impurity content within the deposit was in the range 1.1 to 1.8 at.%. The electrical resistivity for the Cu films on TiN illust rated three regions of the variation according to the substrate temperature , so the deposit at 165<degrees>C had the optimum resistivity value. Howeve r, the coarsened microstructures of Cu on TiN prepared above 275 degreesC g ave rise to higher electrical resistivities compared to those on Si and Si3 N4 substrates.