Effect of in-line electron beam treatment on the electrical performance of Cu/organic low-k damascene interconnects

The interface quality and reliability issues have shown significant importance in Cu/organic low-k damascene integration. In this letter, a post-etch in-line electron beam (E-beam) treatment was used to modify the interface properties of sidewall barrier/organic low-k dielectric without impairing either the film properties or the dielectric constant. X-ray photoelectron spectroscopy (XPS) analysis indicated that oxygen content at the low-k surface, which mostly came from oxygen/moisture intake from ambient during process, was eliminated by E-beam exposure and subsequent rapid thermal annealing. As a result, Cu/organic low-k interconnects exhibited a lower line-to-line leakage current and a higher breakdown strength. The interconnect structures, after this in-line E-beam treatment process, also showed a good reliability performance against thermal stress, with good leakage current characteristics after a 500-h burn-in at 200°C.