CD uniformity improvement for sub 20 nm DRAM process with negative tone development

NTD (Negative Tone Developer) technology with application of developer to ArF immersion is one of the technologies that is well known and widely used for enabling better optical image contrast. For critical layer processes, CD (Critical Dimension) control is more difficult with narrow trench and contact hole pattern. Since it is difficult to obtain better CDU (Critical Dimension Uniformity) once mask and resist set have been fixed, new NTD processes are required to improve it. CXMT (Chang Xin Memory Technologies) has been continuously developing manufacturing processes based on new NTD method for narrow pattern DRAM process with TEL™ (Tokyo Electron Limited). In this paper, we discuss our work for CDU improvement with new process on Global, Inter, and Intra shot CDU as well as the optimization results of chemical consumption.