A structured routing architecture and its design methodology suitable for high-throughput electron beam direct writing with character projection

To improve throughput of Electron Beam Direct Writing (EBDW) with Character Projection (CP) method, we propose a structured routing architecture (SRA) where VIA placement and wire-track interchange is restricted so as to reduce possible layout patterns in VIA and metal layers. CP exposure is accelerated by the increased figure numbers of VIAs and metal segments in each CP character due to the reduced character variations. We demonstrate a design flow that enables routing on the interconnect layer with the limited flexibility using a commercial routing tool and a few own programs. We also present a methodology to design character stencils with improved area efficiency by character superposition. Our experimental results proved the architecture's feasibility in achieving the target EBDW performance in 14nm technologies.