In the era of nano devices, patterning technology encounters many challenges, which arise from not only lithography but also plasma etching. Water-immersion lithography (193 nm) is clearly within sight and many lithography technologies, including extreme ultra-violet (EUV) and other methods, are being developed as the next generation lithography technologies. For nano device etching, introduction of very thin photoresist and more complex device structure requires subtle improvement of etching. Also, the adoption of new materials such as high-k dielectric, metal gate, and phase change materials require more improvement in the view point of profile and selectivity. Finally, since the process window is getting narrower, control and monitoring technologies such as advanced process control (APC) and advanced equipment control (AEC) are strongly required. (C) 2007 Elsevier B.V. All rights reserved.