Research Of Double Patterning Technology Based On Optical Proximity Correction

As the VLSI technology scales into deep submicron nodes, critical dimension (CD) becomes increasingly smaller and almost encounters its theoretical limitation of exposure system. This situation causes serious image distortion on wafer after lithography process, namely Optical Proximity Effect(OPE).According to the 2007 edition of International Technology Roadmap for Semiconductors(ITRS), Double Patterning Technology(DPT) is widely accepted as one of the main RET(Resolution Enhancement Technology) candidate for next 45nm node and below in lithography design.DPT is a promising technique that bridges the anticipated technology gap for next nodes by utilizing current tools without changing much. However, Double Patterning Technology has complicated process steps that may prevent it from being applied in production. It faces a variety of challenges, from overlay brought by lithography system, to layout pattern decomposition, optical proximity correction (OPC) as well as verification for decomposition, all of which would definitely impact its product yield and manufacturing turn around time.In this paper, we mainly talk about the interactions between DPT and OPC and propose a new OPC methods based on segment information reuse according to DPT flow and decomposition problem. To widespread deployment of double patterning, decomposition becomes the first major barrier, especially for random logic circuit (2D), which always causes serious pinch, line-end pull back, etc after stitching two masks together. Here, we newly classify Double Patterning decomposition into three categories from OPC division, natural split, re-cuts related split and redesign needed split, back two of which will inevitably influence its followed step-OPC. By analyzing intensity, ripple effect, segment move and dynamic range, we discuss the correlation between layout split and OPC. Also, regarding illumination optimization based on different parameters, the effect on moderate decomposition and aggressive decomposition for layout is discussed and expected.Due to its complex process, Double Patterning does spawn a couple of issues that would need addressing before proceeding into production environment. The most concerned factor is that its complexity and data volume increase dramatically. By analyzing decomposition problems and Optical Proximity Correction (OPC) reuse scheme based on segments, a relationship is set up between changed layout from re-split and previous OPC data, namely fragmentation and offset information. To test this method, experiments are carried out and show that a large amount of runtime is saved while keeping the same satisfied results and the circle in DPT is shortened efficiently.