Electrical characterization of low permittivity materials for ULSI inter-metal-insulation

The ever increasing demand for high performance integrated devices results in more and more low dielectric constant materials being proposed to replac e silica for interconnects insulation. We present results concerning two or ganic materials (Flare and SiLK) and one mineral (porous silica). These mat erials present good dielectric characteristics when dry, i.e. they have a v ery low leakage current and a long breakdown time to failure. However, mois ture uptake weakens their characteristics. The leakage current is increased , but generally not in a crucial manner. More critical is the drastic decre ase of the breakdown time to failure. This sensitivity must be taken into a ccount both in wafer encapsulation design and during the process of elimina ting residual moisture before encapsulation of each low-k material layer. ( C) 2000 Elsevier Science Ltd. All rights reserved.