Post porosity plasma protection: Scaling of efficiency with porosity

Abstract

Increasing the porosity of oxycarbosilane dielectrics is a key approach to lower the interconnect signal delay and thus enable manufacturing of lower power consumption and higher performance microprocessors. However, this path leads to excessive dielectric process damage as the industry adapts procedures developed for dense and microporous insulators to mesoporous materials. Currently ultralow dielectric constant (k) materials cannot be integrated at the most aggressive pitch. Here, it is reported that the post porosity plasma protection enables the mitigation of process damage across a wide range of porosity regimes. The exponential increase in plasma damage with porosity when going from microporous k = 2.4 to mesoporous k = 1.8 is shown. Using the same range of materials, the strategy allows a reduction in process damage to a constant minimal level on both blanket wafers and patterned structures. The results demonstrate how the strategy can enable the extendibility of current materials and processes to future technology nodes. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.