Fabrication of Interconnect Structures

A method of an interconnect structure which comprises:

• forming a dual damascene interconnect structure with at least two interconnect lines and at least one via connected to at least one of said at least two interconnect lines embedded in a first dielectric;
• removing the first dielectric from between the at least two interconnect lines to a depth of at least equal to the height of the lines;
• depositing a thin formal passivation dielectric by a supercritical fluid based process or an atomic layer deposition from a tertiary amine based reagent and/or silylating agent to coat the tops and exposed sidewalls of said lines and the bottom of the via between the at least two interconnect lines;
• filling the space between the at least two interconnect lines with a second dielectric with a lower dielectric constant than the first dielectric;
• planarizing the second dielectric by polishing using the conformal dielectric as polish stop layer;
• and optionally capping the top surface of the resulting structure with a third dielectric.

A method for fabricating a damascene or dual damascene interconnect structure which comprises forming a damascene or dual damascene interconnect structure with a least two interconnect lines and wherein the at least two interconnect lines are embedded in a first dielectric;

• and optionally dielectric hard mask spanning the space between said interconnect lines and nominally coplanar with the top surface of said lines and a diffusion barrier cap dielectric on top of the at least two interconnect lines;
• which comprises:
• depositing a first dielectric and optionally the dielectric hard mask using supercritical fluid based processing;
• patterning photoresist layers to form the at least two interconnect line pattern on top;
• transferring the at least two interconnect line pattern into the dielectric using photolithography and reactive ion etching;
• stripping the residual photoresist using plasma ashing;
• repairing any plasma damage to the first dielectric and the optional hard mask using a supercritical fluid based silylation treatment;
• filling the interconnect lines and vias with a conductive liner and a conductive fill material;
• planarizing the conductive liner and conductive fill material using chemical mechanical polishing;
• cleaning the top of said at least two interconnect lines and said optional dielectric hard mask using supercritical fluid based cleaning solutions;
• repairing any incidental damage to the first and/or second dielectric surface by silylation;
• and depositing a diffusion barrier cap dielectric using a supercritical fluid based deposition.