Enhanced Chemical Vapor-deposited Copper Thin Films On Self-assembled Monolayers And Related Simulations

Copper has lower resistivity and higher resistance to electromigration and stress migration compared with aluminum alloys. To fabricate the high performance interconnects with low RC delay, the integration of low resistivity metal wiring and low κ inter-metal dielectric is crucial for next generation ultra large-scale integrated circuit technology. To implement copper into a metal line via interconnects, the dual damascene process is required because copper is difficult to etch. In considering methods to deposit copper, Metal-Organic Chemical Vapor deposition (MOCVD) processes have several advantages such as the ability to achieve good conformality and the possibility of selective deposition.This research was based on a MOCVD system, which was designed, built previously. Cu^(Ⅱ)(hfac)₂ was used as precursor, and hydrogen as carrier gas and reactant. Chemical vapor deposited copper thin films on silicon substrate and 2- (di- phenyl- phosphino) ethyl- tri-ethoxy- silane (PHOS) self-assembled monolayers (SAMs). It can be concluded like these:Annealing by nitrogen is the best process that can improve electromigration and benefit the roughness of copper thin films on silicon substrate. Moreover, annealing by nitrogen is beneficial to the adhesion of thin films. Thus, annealing by nitrogen is an ideal post process. Copper thin films can be improved on PHOS SAMs. It can decrease the activated energy of reaction, increase depotion rate. Meantime, it is effective in preventing Cu atoms drift into the oxide layer. In a word, the SAMs containing alkyphosphine can be effective copper atoms diffusion barrier.Further more, a chemical vapor deposited copper thin films on Cu (100) surface model, which was based on kinetic lattice Monte Carlo (KLMC), has been built, and do some related simulations. It can be found that there is litter relation between activated sites ratio and roughness. But the roughness decreased by the increasing temperature, while the number of remained precursor molecules decreased, after reach a critcal temperature, the roughness and the number of molecules keep unalterable.