Highly accurate cell projection mask for applications to sub-130 nm patterning

In this article, we introduce the constraints of cell projection mask (CPM) design for application to sub-0.13 mu m patterning and the modified fabric ation technology for the highly accurate CPM. First, we investigated the co nstraints of CPM design such as Coulomb interaction and proximity effect. E specially, in order to reduce beam blur effect, we applied mask bias and op timized shot size that could be obtained by calculated space margin and exp eriment. Second, we made highly accurate CPM using modified fabrication tec hnology, which included deep trench etching process with oxide barrier, the stacked protection layer, and effective cleaning process. The minimum feat ure size achievable in this technology is 1 mu m, corresponding to 0.04 mu m on a wafer due to 1/25 reduction ratio of cell projection e-beam lithogra phy system. Using CPM made by above process, we successfully defined 0.08 m u m lines-and-spaces and 0.1 mu m contact hole patterns with a standard dev iation of 0.005 mu m. In addition, we also compared the lithographic perfor mance of the CPM samples with 20- and 10-mu m-thick diaphragms. According t o our results, thin CPM has more advantages than a thick one in view point of fabrication and low electron transmittance of sidewall. (C) 1999 America n Vacuum Society. [S0734-211X(99)13106-8].