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In order to implement highly porous PECVD SiOCH films with k = 2.0 in ILD integration, the UV-assisted restoration to remove plasma damages related with dry etch and pore sealing by plasma enhanced ALD (PEALD)-SiN formation to prevent the metal penetration into the film during subsequent metallization process was investigated. Sequential application of the restoration and pore sealing processes was proved to be the best solution enabling successful sealing capability with preserving pristine k-value of the porous SiOCH films.

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A new plasma-enhanced organic monomer-vapour polymerization (plasma polymerization) method has been developed. It was used to make a divinyl siloxane bis-benzocyclobutene (DVS-BCB) polymer film for Cu dual-damascene interconnects that had high thermal stability and a low dielectric constant, k = 2.6. The method consists of the vaporization of organic monomers, transportation of monomers in the gas phase, and polymerization by plasma to make the polymer film. The method eliminates polymer oxidation of DVS-BCB during the polymerization in high vacuum, which improves the film's thermal stability. The thermal stability of plasma-polymerized BCB (p-BCB) exceeded 400˚C because of the higher deposition temperature, and the film had a high resistance to Cu diffusion at 400˚C annealing. The narrow-pitched Cu/BCB damascene lines showed a 35% reduction in line capacitance compared with Cu/SiO 2 ones. The p-BCB is shown to be a strong candidate for Cu/low-k interconnects.

A plasma-enhanced co-polymerization technique was developed for low-k/Cu damascene integration on 300 mm wafers. This technique enables us to control dielectric film properties by introducing organo-siloxane and hydrocarbon into a He-plasma. The growth rate of the low-k film derived from divinyl siloxane–benzocyclobutene (DVS–BCB) as a matrix monomer is increased by adding C2H2 as a deposition acceleration monomer and the Young's modulus was enhanced by adding diisopropenylbenzene (DIPB) or divinylbenzene (DVB) as a reinforcement monomer. Cu damascene interconnects with plasma polymerized low-k films were successfully fabricated on 300 mm wafers.