Robust ultra-low k interconnect structures using bridge-then-metallization fabrication sequence

• Main Authors: PURUSHOTHAMAN, SAMPATH, SAENGER, KATHERINE L, COLBURN, MATTHEW E, HUANG, ELBERT E, NITTA, SATYANARAYANA V
• Format: Patent
• Language: English
• Published: 01.11.2006
• Edition: 7
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

A method for fabricating low k and ultra-low k multiplayer interconnect structures on a substrate includes: a set of interconnects separated laterally by air gaps; forming a support layer in the via level of a dual damascene structure that is only under the metal line; removing a sacrificial dielectric through a perforated bridge layer that connects the top surfaces of the interconnects laterally; performing multilevel extraction of a sacrificial layer; sealing the bridge in a controlled manner; and decreasing the effective dielectric constant of a membrane by perforating it using sub-optical lithography patterning techniques.