BEOL integration of highly damage -resistant porous ultra low-k material using direct CMP and via-first process

Abstract

We have demonstrated porous ultra low-K (ULK)/Cu interconnect integration using via first integration scheme and a direct ULK CMP process. The key features of the damage-resistant porous ULK material were novel material chemistry, a higher carbon concentration (15.4 atm%) and an improved pore structure. These improved features of the new ULK material enabled superior process-induced dielectric material damage during patterning etch, resist strip, and ULK direct CMP. Interconnect structures fabricated using the conventional ULK material showed high short leakage currents and open failures due to moisture uptake. The integrated structures of the new, robust porous ULK material exhibited good electrical properties. The target capacitance values have been achieved for future porous ULK/Cu interconnects. © 2006 IEEE.