A silicon nitride film, Damascene Nitride™, is deposited in a plasma-enhanced chemical vapor deposition ͑PECVD͒ chamber with a conical hole faceplate using silane and ammonia as precursors. Fourier transform infrared analysis indicates that Damascene Nitride is similar to a high-density plasma nitride film. Hydrogen forward scattering spectroscopic analysis shows the film's hydrogen content to be 13%, ϳ6% less than other PECVD nitride films, leading to a 20% improvement in etch selectivity to fluorinated silicate glass. Secondary ion mass spectrometric analysis shows that Cu diffusion is Ͻ250 Å in the nitride; a low leakage current (10 Ϫ12 A) is confirmed through bias temperature stress testing. The higher density of Damascene Nitride leads to higher etch selectivity and better Cu barrier properties, allowing a thinner nitride film to be used. Thinner nitride layers, in addition to the lower dielectric constant ͑͒ of Damascene Nitride, leads to a 5-6% reduction in resistance-capacitance delay when Damascene Nitride is used with low-dielectric materials.

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A Pecvd silicon nitride film, Damascene Nitride™, is deposited in a PECVD chamber with a hollow cathode faceplate using silane and ammonia as precursor gases. Various techniques (FTIR, RBS-HFS, SIMS, TDS and BTS) were used to characterize the structure, composition, density and wet etch rate of the film. FTIR analysis indicates that Damascene Nitride is very similar to a high density plasma (HDP) nitride film. HFS analysis shows the film's hydrogen content to be 13%,∼6% less than other PECVD nitride films, leading to a 20% improvement in etch selectivity to FSG. The film wet etch rate is 2 times slower than that of other PECVD nitrides, and the dielectric constant k was measured to be 6.8, which is lower compared to other PECVD nitrides and HDP CVD nitrides where k∼ 7.0 and 7.5, respectively. SIMS analysis shows that Cu diffusion is <250Å in the nitride, and low leakage current (10-10 A) is confirmed through BTS testing. The higher density of Damascene Nitride leads to higher etch selectivity and better Cu barrier properties, allowing a thinner nitride film to be used. Thinner nitride layers, in addition to the lower k of Damascene Nitride, leads to a 5-6% reduction in RC delay when Damascene Nitride is used with low k dielectric materials.

The film properties of two PECVD deposited dielectric copper barrier films have been optimized to improve BEOL device reliability in terms of electromigration. Two critical aspects that affect electromigration are the dielectric barrier film hermeticity and adhesion to copper. We use a method to quantify the barrier film hermeticity and have optimized the hermeticity of the BLOκ™ low-κ dielectric barrier film to be similar to that of silicon nitride. By using FT-IR we find that the film porosity has a much stronger effect than the film stoichiometry on hermeticity. In addition, the interfaces between Damascene Nitride™ with copper, as well as BLOκ with copper have been engineered to improve the interfacial adhesion energy to >10 J/m 2 for both Damascene Nitride and BLOκ.

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