Low defect density conformal Ti-Si-N and Ti-X-N foundation barrier films

摘要

The present invention relates to a CVD process of a Ti-Si-N or Ti-BN film, in which one feed gas (preferably TDMAT) is a source of titanium and nitrogen and the other feed gas Is used as the source of silicon or boron. This makes it possible to avoid nucleation of gaseous particulates while providing good conformality. Once the deposition is completed to the required thickness, the silicon / boron feed gas continues to flow for some time after the titanium / nitrogen or titanium / boron source is shut off. This results in a Ti-N film having a Si-rich (Si-rich) or B-rich (B-rich) surface, which is a conformal film and has a low defect density. In a second embodiment one feed gas, such as TDMAT, is thermally decomposed to form a Ti-N layer. Post-deposition anneal is performed in a gas atmosphere supplying silicon or boron to incorporate these materials into the layer. Incorporation of silicon or boron into the layer can minimize the absorption of oxygen into the membrane and can stabilize the membrane. Si-rich or B-rich surfaces are beneficial for the application of improved metallization because they aid in wetting of Al and increasing the adhesion of Cu. Compared with the sputtering method, the present invention provides a method of depositing a film with easier control of step coverage and Si / Ti ratio. Compared to the TDEAT + NH ₃ + SiH ₄ method, the present invention eliminates the gas phase reaction between the Ti source and NH ₃ .