Effective repair to ultra-low-k dielectric material (k∼2.0) by hexamethyldisilazane treatment

Abstract

In situ real-time monitoring of profile evolution during plasma etching of mesoporous low-dielectric-constant SiO 2Patterning of fluorine-, hydrogen-, and carbon-containing SiO 2 -like low dielectric constant materials in highdensity fluorocarbon plasmas: Comparison with SiO 2 O 2 plasma ashing is commonly used to remove photoresist. The effect of O 2 plasma ashing on the porous organosilicate glass (CH 3 SiO 1.5 ) n , one of the spin-on materials, is investigated. O 2 plasma can oxidize the methyl groups in porous organosilicate glass ͑POSG͒, which leads to the formation of Si-OH groups. The hydrophilic Si-OH groups will induce moisture uptake so that electrical degradation will occur in POSG film. Pure hexamethyldisilazane ͑HMDS͒ vapor ͑100% HMDS͒ can react with the Si-OH groups in POSG film. It converts hydrophilic Si-OH groups into hydrophobic Si-O-Si(CH 3 ) 3 groups against moisture uptake. The leakage current density decreases by a factor of 2-3 and the dielectric constant decreases from 3.62 to 2.4 when O 2 plasma-damaged POSG undergoes HMDS treatment at 80°C for 15 min. Therefore, HMDS treatment is the effective technique to repair the electrical degradation to POSG film during photoresist stripping processing.

Prospects for dielectric constant reduction in integrated circuits interconnects

“…As a consequence, the material's hydrophobicity is recovered and the moisture uptake is avoided. [28] The main limitation of this approach is the steric hindrance of the large silylation molecules that react first on the outer surface and prevent the diffusion of the silylation agents inside the pores. [29] As a consequence, even if the surface hydrophobicity is locally recovered, it is much more difficult to repair the inner pores that are also partially hydrophilic.…”

Low‐kMaterials: Recent Advances

“…The second process utilizes reactive silylating agents to convert hydrophilic Si-OH groups into hydrophobic derivatives [113][114][115][116][117][118][119]. This reaction is best accomplished with highly reactive chlorosilanes, but the corrosive nature of the by-product HCl and the potential to introduce chloride ions makes them poor candidates.…”

Erosion rate variations during XPS sputter depth profiling of nanoporous films

“…Treatment with HMDS has been evaluated as a method to restore film hydrophobicity following plasma treatment. 5 The HMDS reacts with silanol groups according to 2Si-O-H C CH 3 3 -Si-NH-Si-CH 3 3 ! 2Si-O-Si-CH 3 3 C NH 3 1…”