^4fInnovative Radical Oxidation Nitridation by Damage-Free RLSA Plasma for Sub-100nm Nodes

摘要

^7fIn leading edge device fabrication beyond the 90nm technology node, it is important to reduce the gate oxide thickness as the equivalent oxide thickness (EOT) scales down to 1.4nm. To solve the issues for thinner EOT gate oxidation, plasma nitridation treatment is expected to replace the existing gate stack formation. Low electron temperature and high density plasma generated by the radical line slot antenna (RLSA) is developed on Trias SPA by Tokyo Electron Limited and is becoming a leading solution for customers considering nitridation. In this paper, the RLSA plasma was investigated for preparation of thin gate oxide stack formation. Since RLSA creates low damage in the Si substrate, no post nitridation anneal is necessary to meet thin gate stack specification. For an advanced transistor gate of EOT=9.5A it was successfully demonstrated that gate oxide leakage current reduced by 1/4. Ion current gain was also improved from that of non nitrided gate oxide. Furthermore, the RLSA was successfully demonstrated for the Flash memory tunnel oxide formation, poly/metal gate side wall re-oxidation, corner oxidation of shallow trench isolation, high-K gate treatment, and DRAM capacitor treatment.