A NOVEL SUBHALF MICRON AL-CU VIA PLUG INTERCONNECT USING LOW DIELECTRIC-CONSTANT MATERIAL AS INTER-LEVEL DIELECTRIC

A novel AI-Cu via plug interconnect using low dielectric constant (low -epsilon) material as inter-level dielectric (ILD) has been demonstrat ed, The interconnect structure was fabricated by spin-on deposition of the low-epsilon ILD and physical vapor deposition (PVD) of the AI-Cu, Excellent local no planarization was achieved by a two-step spin-on c oating process. The dielectric constant of the low-epsilon ILD is abou t 2.7, which leads to significant interconnect wiring capacitance redu ction. For the first time, completely filled Al-Cu:0.5% plugs with nea rly vertical sidewalls were fabricated in organic low-epsilon no. Exce llent via fill was observed with via size down to 0.30 mu m. Low via r esistance and excellent via reliability have been observed.