A novel sub-half micron Al-Cu via plug interconnect using low dielectric constant material as inter-level dielectric

A novel Al-Cu via plug interconnect using low dielectric constant (low-/spl epsiv/) material as inter-level dielectric (ILD) has been demonstrated. The interconnect structure was fabricated by spin-on deposition of the low-/spl epsiv/ ILD and physical vapor deposition (PVD) of the Al-Cu. Excellent local ILD planarization was achieved by a two-step spin-on coating process. The dielectric constant of the low-/spl epsiv/ no is about 2.7, which leads to significant interconnect wiring capacitance reduction. For the first time, completely filled Al-Cu:0.5% plugs with nearly vertical sidewalls were fabricated in organic low-/spl epsiv/ ILD. Excellent via fill was observed with via size down to 0.30 μm. Low via resistance and excellent via reliability have been observed.