The present invention provides methods for fabricating integrated circuit
structures for use in semiconductor wafer fabrication techniques. A Cu
diffusion barrier/Cu seed sandwich layer is deposited on a substrate. A
first sacrificial layer, deposited on the sandwich layer, is developed to
form a cavity. A first Cu layer is selectively deposited on the sandwich
layer inside the cavity. A second sacrificial layer is deposited on the
first sacrificial layer and on the first Cu layer. A cavity is formed in
the second sacrificial layer, exposing at least a portion of the first Cu
layer. A second Cu layer is selectively deposited in the second
sacrificial layer cavity including the exposed portion of the first Cu
layer. The combination of the first and second Cu layers forms a Cu
component. Subsequently, the first and second sacrificial layers are
removed resulting in a Cu component that is free standing on the sandwich
layer, such that the top and sides of the component are exposed. Sandwich
layer portions extending from the Cu component are removed from the
substrate, thereby forming an exposed sandwich layer edge between the
surface of the Cu component and the substrate. A Cu diffusion barrier
layer is deposited on the Cu component and on the exposed edge of the
sandwich layer, resulting in a Cu barrier layer encapsulated component.
The encapsulated component is encased in a dielectric layer. Similarly,
Cu components of the present invention are fabricated by means of
selective electroless Cu deposition in a sacrificial layer cavity having
a metal layer that is formed by selective electroless deposition of a
metal on a sensitizer layer. Examples of Cu components and encapsulated
Cu components of the present invention include vertical interconnects and
inverted damascene structures.