Control of process-induced damages in self-assembled porous silica/Cu damascene interconnects for 45nm node and beyond

New methods to recover process-induced damages of a self-assembled non-periodic porous silica (k=2.1) film were developed for Cu/low-k damascene interconnects for 45nm technology node and beyond. It is shown that process-induced damages can be suppressed by employing 1,3,5,7-tetra-methylcyclotetrasiloxane (TMCTS) vapor annealing after dry etching, by using a new suppressor for a Cu plating solution, and by post Cu-CMP cleaning with ethanol. Time-dependent dielectric breakdown lifetime of the non-periodic porous silica/Cu damascene was evaluated to be more than 10 years.