Effect of plasma treatments on a low-k dielectric polymer surface

Abstract

The ongoing transition to lower dimension devices requires the replacement of SiO 2 by a lower-k dielectric insulator. Such materials are porous, introducing the need for sealing against penetration of gaseous and/or liquid species during subsequent processing. In this work, we investigate the effect of different plasma treatments on a porous low-k polymer film. Ion bombardment induces the formation of a dense surface layer capable of sealing the polymer. A competing etching reaction by the plasma gases determines the extent of the densified layer. Structural and chemical changes induced by the plasma treatments can extend into the bulk of the film and irreversibly change its properties. Exposing the plasma treated films to chemical precursors during an atomic layer deposition process is used to test sealing. The sealing behavior is discussed in view of the reactivity of the plasma and the post sealing temperature treatment.

Improved characterization of Fourier transform infrared spectra analysis for post-etched ultra-low-κ SiOCH dielectric using chemometric methods

“…3 This is explained due to smaller dissociation energy for Si-C ͑ϳ447 kJ/ mol͒ compared to Si-O ͑ϳ800 kJ/ mol͒. 4 It was observed that during the carbon depletion dangling bonds occur, 5 which form new Si-O or Si-OH bonds after exposing to the atmosphere. This results in an unfavorable degradation of the dielectric properties, i.e., increasing -value.…”

Electrical Breakdown in Advanced Interconnect Dielectrics

“…Unfortunately, dielectric degradation during certain process steps is a major concern for both LKs (major concern) and porous ULKs (much greater concern) because they are susceptible to damage during the ashing process (in particular, O 2 -based plasmas) to remove photoresist residues [152][153][154][155][156][157][158][159][160][161]. The decomposed Si-CH 3 and C-H bonds [168] can form surface silanol (Si−OH) or Si-H bonds [169] and subsequently enable bulk moisture absorption [170,171]. The decomposed Si-CH 3 and C-H bonds [168] can form surface silanol (Si−OH) or Si-H bonds [169] and subsequently enable bulk moisture absorption [170,171].…”

Characterization of plasma damaged porous ULK SiCOH layers in aspect of changes in the diffusion behavior of solvents and repair-chemicals

“…It is reported that during plasma processes the ULK film is damaged, which is related to the carbon loss 3 . It was observed that during the carbon depletion dangling bonds occur 4 . After exposure to the atmosphere these dangling bonds can form new Si-O or Si-OH bonds.…”