The Effects of Plasma Treatments and Subsequent Atomic Layer Deposition on the Pore Structure of a k = 2.0 Low-k Material

摘要

In order to improve the characteristics of future integrated circuits, low dielectric constant (low-k) materials are employed. In this paper we describe in detail the characteristics of k = 2.0, SICOH films treated by capacitively coupled Ar/N_2 and Ar/H_2 plasmas, which were applied in order to modify the top surface of the film. New insights were obtained about the porous structure of the pristine and the plasma treated films: analyses indicated that the investigated plasma treatments reduced the pore size in the top ten nm of the films, while partial carbon depletion was found down to a few tens of nm inside the film. For the integration of metal barriers deposited by Atomic Layer Deposition in interconnect technologies, precursor penetration into the porous low-k dielectric should be avoided. We investigated precursor penetration in the pores during TaN Atomic Layer Deposition on the pristine and the plasma treated porous low-k firms. Detailed analyses showed that the plasma induced modifications resulted in a local growth enhancement and pore sealing during the first cycles of the atomic layer deposition process.