A novel Al-reflow process using surface modification by the ECRplasma treatment and its application to the 256 Mbit DRAM

摘要

A novel Al-reflow process with the electron cyclotron resonance(ECR) plasma treatment for the modification of underlayers was developedin a vacuum isolated sputtering equipment. The key feature of thistechnology is the introduction of the in-situ ECR plasma treatment forthe modification of the surface characteristics such as surfacemorphology and stoichiometry of the TiN wetting/barrier layer. Highwettability of the Al film was obtained on the ECR-treated TiN surface,producing a conformal Al film on the sidewall of the contact hole beforethe reflow process. Consequently, complete filling of contact holes withAl was achieved in deep sub-micron contact holes with a high aspectratio. This study has demonstrated that the Al-reflow process can beextended to the process of the devices of 256 Mbit DRAM generation andbeyond