Abstract: Backside contact structures include etch selective materials to facilitate backside contact formation. An integrated circuit structure includes a frontside contact region, a device region below the frontside contact region, and a backside contact region below the device region. The device region includes a transistor. The backside contact region includes a first dielectric material under a source or drain region of the transistor, a second dielectric material laterally adjacent to the first dielectric material and under a gate structure of the transistor. A non-conductive spacer is between the first and second dielectric materials. The first and second dielectric materials are selectively etchable with respect to one another and the spacer. The backside contact region may include an interconnect feature that, for instance, passes through the first dielectric material and contacts a bottom side of the source/drain region, and/or passes through the second dielectric material and contacts the gate structure.

Abstract: Processes of forming an insulated wire into an interlayer dielectric layer (ILD) of a back-end metallization includes thermally treating a metallic barrier precursor under conditions to cause at least one alloying element in the barrier precursor to form a dielectric barrier between the wire and the ILD. The dielectric barrier is therefore a self-forming, self-aligned barrier. Thermal processing is done under conditions to cause the at least one alloying element to migrate from a zone of higher concentration thereof to a zone of lower concentration thereof to further form the dielectric barrier. Various apparatus are made by the process.