Interconnect structure with a cap layer on an IMD layer and a method of formation thereof

摘要

An interconnect structure comprises a first level metal wiring line patterned on a semiconductor substrate, an inter-metal dielectric (IMD) layer formed on the metal wiring line, a contact plug passing through the IMD layer and electrically connected to the top of the first level metal wiring line, and a second level metal wiring line patterned on the IMD layer and electrically connected to the top of the contact plug. A cap layer is sandwiched between the top of the IMD layer and the bottom of the second level metal wiring line.