(Invited) Engineered Combinations of Inorganic ALD/CVD Layers and Monomolecular Organic Films

Capacitance scaling in damascene interconnects is achieved by introducing ultra-porous low dielectric constant  materials. Nevertheless, one of the key issues in the integration of such porous materials is their inability to prevent gaseous penetration, e.g. during the metallization.

Several strategies are being followed to minimize the processing damage to the porous films during etching and ashing. The subsequent important step is to seal the pores at the surface, especially at the sidewalls after the trench and via etching. This is to prevent metal or precursor penetration during the metallization process, especially by advanced conformal deposition techniques such as chemical vapor deposition (CVD) and atomic layer deposition (ALD).

There are several routes to sealing: i) by thin film deposition; ii) by plasma-surface interaction; iii) by surface cross-linking/reconstruction. In this contribution, we report about the achievement of a complete pore sealing by combining a surface treatment of the low-k material together with self-assembled monolayers (SAMs) deposition and a low temperature ALD and CVD processes.  In particular, CVD-based MnSixOy films are serious candidates for sub-25 nm-wide trench and via metallization technology because of their conformal nature and their ability to act as effective Cu diffusion barriers in the range of 1-2 nm thickness.

Self-assembled molecular nanolayers composed of sub-1 nm organic chains and terminated with desired functional groups are attractive for modifying surface properties for a variety of applications, such as lubricants, in nanolithography, corrosion protection and in the crystallization of biominerals. Monolayers can help engineering thin-film interfaces, both as active components in molecular devices, and as passive layers, inhibiting interfacial diffusion, promoting adhesion and toughening brittle nanoporous structures.

In this contribution, we report  about  the interaction between CVD and ALD films and organic thin films. Special attention is paid to selective ALD/CVD growth on functionalized surfaces having modulated surface energies.