CONTEXT

The invention concerns novel copper or silver complexes and their use for gas-phase chemical deposition of metal copper or silver almost free of impurities. Many precursors are known in the prior art for developing films consisting of pure copper. The most promising precursors are coordination complexes of copper in the (+1) oxidation state stabilized by means of a ligand, in which the copper is coordinated with a b-diketonate containing fluorine atoms.

Studies carried out on these precursors show that their molecular structure is decisive for the reproducible production of good quality films.

Now, in certain cases, in particular when the copper film is deposited on barrier such as TiN, Ta or TaN as required by the technology, even though the copper film contains only a very small amount of fluorine, this fluorine diffuses and become concentrated at the interface between the copper and the barrier.

The consequence of this is:

-          A break in the electrical conductivity between the baste transistor and the copper film, which increases overall, the resistivity of the contact, due to the insulating nature of the fluorine-rich film.

-          Insufficient adhesion of the copper film on the barrier film.

However, there remains a need for a copper or a silver complex for the reproducible production of electronic circuits based on thin copper or silver films for filling vertical interconnections and lines without fault and with low resistivity and a good thermal stability in the long term. Also, there remains a need for a precursor which is completely free of fluorine atoms, while at the same time being volatile and sufficiently stable to be exploited.