Reliability limitations to the scaling of porous low-k dielectrics

Abstract

We show that processes used to fabricate advanced porous dielectrics can exhibit reliability approaching the intrinsic capability of the material. Combining this with simulations of failure distributions as a function of porosity and line edge roughness we demonstrate that failure times due to electrical breakdown rapidly decrease below k=2.3. The rapid failure time decrease is due to the statistical nature of increasing porosity (decreasing k), which leads to a shortening of the percolation path for dielectric breakdown. Continued scaling will require greater understanding of the breakdown impact on circuits as well as materials innovations to improve robustness.