Dual Damascene: a ULSI wiring technology

Escalating density, performance, and (perhaps most importantly) manufacturing requirements associated with ULSI semiconducting wiring, necessitate a metamorphosis in interconnection technology. To meet these needs, an inlaid fully integrated wiring technology called Dual Damascene has been designed and demonstrated at IBM´s Essex Junction, Vermont, facility. A subset of the technology´s features has been successfully implemented in the manufacture of IBM´s 4-Mb DRAM. The Dual Damascene structure achieved is a planar, monolithic-metal interconnect, comprising a vertical metal stud and horizontal metal interconnect, both embedded in an insulator matrix. The complete Dual Damascene technology features a unique process sequence, chemical-mechanical insulator planarization, stacked photolithographic masks, clustered stud and interconnect etch, concurrent stud and interconnect metal fill, and chemical-mechanical metal etchback