Use of difunctional silylation agents for enhanced repair of post plasma damaged porous low k dielectrics

Abstract

The use of silylation as a technique to restore hydrophobicity in plasma damaged porous organosilicate based films for low dielectric constant (k) applications has gained popularity in recent years. However, most of the published work in this field has focused on the use of Hexamethyldisilazane (HMDS) as a silylation agent and, to date, there has been no systematic study published which evaluates the efficiency of either alternate silylation agents or the role of the medium in which silylation is performed. In this work, it will be shown that by studying the effect of the functionality, size, and effectiveness of the leaving group, it is possible to identify silylation agents that are more effective than HMDS. In particular, it will be shown that the use of difunctional silylation agents with more effective leaving groups leads to more effective silylation. It will also be shown that lowering the surface tension of the silylation medium leads to more effective silylation. Finally, it will be shown that the use of difunctional silylation agents in a patterned interconnect structure with porous organosilicate low k films leads to lower capacitance and leakage than HMDS, suggesting better recovery of hydrophobicity through the damaged regions of the film. © 2006 Materials Research Society.