Methods and apparatus for transient protection of a sensitive surface of a substrate are described. Methods that facilitate transient protection of a sensitive surface of substrate include depositing a sacrificial capping layer on a sensitive surface of the substrate after a processing operation. The capping layer deposition and the prior processing operation occur under vacuum. In some embodiments, for example, the capping layer deposition and the prior processing operation occur in different modules of a tool connected by a vacuum transfer chamber. In other embodiments, the capping layer deposition and the prior processing operation occur in the same module Methods that facilitate transient protection of a sensitive surface of substrate include removing the capping layer from the sensitive surface of the substrate prior to a subsequent processing operation. The removal is performed without damaging the sensitive surface or underlying layers of the semiconductor substrate.

A metal interconnect structure is doped with zinc, indium, or gallium using top-down doping processes to improve diffusion barrier properties with minimal impact on line resistance. Dopant is introduced prior to metallization or after metallization. Dopant may be introduced by chemical vapor deposition on a liner layer at an elevated temperature prior to metallization, by chemical vapor deposition on a metal feature at an elevated temperature after metallization, or by electroless deposition on a copper feature after metallization. Application of elevated temperatures causes the metal interconnect structure to be doped and form a self-formed barrier layer or strengthen an existing diffusion barrier layer.

A method includes forming a first conductive feature in a first dielectric layer, forming a first metal cap over and contacting the first conductive feature, forming an etch stop layer over the first dielectric layer and the first metal cap, forming a second dielectric layer over the etch stop layer; and etching the second dielectric layer and the etch stop layer to form an opening. The first conductive feature is exposed to the opening. The method further includes selectively depositing a second metal cap at a bottom of the opening, forming an inhibitor film at the bottom of the opening and on the second metal cap, selectively depositing a conductive barrier in the opening, removing the inhibitor film, and filling remaining portions of the opening with a conductive material to form a second conductive feature.

A semiconductor device structure, along with methods of forming such, are described. The semiconductor device structure includes a device, a first dielectric material disposed over the device, and an opening is formed in the first dielectric material. The semiconductor device structure further includes a conductive structure disposed in the opening, and the conductive structure includes a first sidewall. The semiconductor device structure further includes a surrounding structure disposed in the opening, and the surrounding structure surrounds the first sidewall of the conductive structure. The surrounding structure includes a first spacer layer and a second spacer layer adjacent the first spacer layer. The first spacer layer is separated from the second spacer layer by an air gap.

Implementations of low-resistance copper interconnects and manufacturing techniques for forming the low-resistance copper interconnects described herein may achieve low contact resistance and low sheet resistance by decreasing tantalum nitride (TaN) liner/film thickness (or eliminating the use of tantalum nitride as a copper diffusion barrier) and using ruthenium (Ru) and/or zinc silicon oxide (ZnSiO.sub.x) as a copper diffusion barrier, among other examples. The low contact resistance and low sheet resistance of the copper interconnects described herein may increase the electrical performance of an electronic device including such copper interconnects by decreasing the resistance/capacitance (RC) time constants of the electronic device and increasing signal propagation speeds across the electronic device, among other examples.

Various embodiments of the present disclosure are directed towards an integrated circuit (IC) in which cavities separate wires of an interconnect structure. For example, a conductive feature overlies a substrate, and an intermetal dielectric (IMD) layer overlies the conductive feature. A first wire and a second wire neighbor in the IMD layer and respectively have a first sidewall and a second sidewall that face each other while being separated from each other by the IMD layer. Further, the first wire overlies and borders the conductive feature. A first cavity and a second cavity further separate the first and second sidewalls from each other. The first cavity separates the first sidewall from the IMD layer, and the second cavity separates the second sidewall from the IMD layer. The cavities reduce parasitic capacitance between the first and second wires and hence resistance-capacitance (RC) delay that degrades IC performance.

A semiconductor structure includes a fin structure formed over a substrate. The structure also includes a gate structure formed across the fin structure. The structure also includes source/drain epitaxial structures formed on opposite sides of the gate structure. The structure also includes an inter-layer dielectric (ILD) structure formed over the gate structure. The structure also includes a contact blocking structure formed through the ILD structure over the source/drain epitaxial structure. A lower portion of the contact blocking structure is surrounded by an air gap, and the air gap is covered by a portion of the ILD structure.