Method to define poly dog-bone for word line strapping contact at stitch area in embedded dram process

Abstract

A method for fabricating a dog-bone in a DRAM device, comprising the following steps. A semiconductor structure having an upper silicon layer with STIs formed therein is provided. The semiconductor structure has a LOGIC region and a DRAM region with a stitch region therebetween. A polysilicon layer is formed over the semiconductor structure. A dopant is selectively implanted in the polysilicon region within the DRAM region, and the portion of the stitch region within the DRAM region, to form a doped poly segment, and an undoped poly segment within the LOGIC region, and the portion of the stitch region within the LOGIC region. A hard mask is formed over the doped poly segment and the undoped poly segment and patterned to form at least one patterned first hard mask portion only over the word line doped poly segment within the DRAM region. At least one second mask layer portion is formed over the undoped poly segment within the LOGIC region and at least one third mask layer portion is formed over the doped poly segment in the portion of the stitch region within the DRAM region. The doped poly segment and undoped poly segment are etched to form: undoped poly periphery logic gate portions within the LOGIC region; doped poly dog-bone within the portion of the stitch region within the DRAM region; and doped poly word lines within the DRAM region. The second and third mask layer portions are stripped to expose the undoped poly periphery logic gate portions and the doped poly dog-bone.