A semiconductor structure and a method for forming a semiconductor structure are provided. A sacrificial gate layer is removed to form a gate trench exposing a sacrificial dielectric layer. An ion implantation is performed to a portion of a substrate covered by the sacrificial dielectric layer in the gate trench. The sacrificial dielectric layer is removed to expose the substrate from the gate trench. An interfacial layer is formed over the substrate in the gate trench. A metal gate structure is formed over the interfacial layer in the gate trench.

A method includes forming a semiconductor fin extruding from a substrate; forming a sacrificial capping layer on sidewalls of the semiconductor fin; forming first and second dielectric fins sandwiching the semiconductor fin; forming a sacrificial gate stack over the semiconductor fin, the sacrificial capping layer, and the first and second dielectric fins; forming gate spacers on sidewalls of the sacrificial gate stack; removing the sacrificial gate stack to form a gate trench, wherein the gate trench exposes the semiconductor fin, the sacrificial capping layer, and the first and second dielectric fins; removing the sacrificial capping layer from the gate trench, thereby exposing the sidewalls of the semiconductor fin; and forming a metal gate stack in the gate trench engaging the semiconductor fin.

The present disclosure provides a method of fabricating a semiconductor structure in accordance with some embodiments. The method includes receiving a substrate having an active region and an isolation region; forming gate stacks on the substrate that extends from the active region to the isolation region; forming an inner gate spacer and an outer gate spacer on sidewalls of the gate stacks; forming an interlevel dielectric (ILD) layer on the substrate; forming a mask layer over the substrate that exposes a portion of the ILD layer and a portion of the outer gate spacer; selectively etching the exposed portion of the outer gate spacer, resulting in an air gap between the inner gate spacer and the ILD layer; and performing an ion implantation process on the exposed portion of the ILD layer to seal the air gap.

A method of forming a semiconductor device includes: forming a gate structure over a fin that protrudes above a substrate; forming source/drain regions over the fin on opposing sides of the gate structure; forming a first dielectric layer and a second dielectric layer successively over the source/drain regions; performing a first etching process to form an opening in the first dielectric layer and in the second dielectric layer, where the opening exposes an underlying electrically conductive feature; after performing the first etching process, performing a second etching process to enlarge a lower portion of the opening proximate to the substrate; and forming a contact plug in the opening after the second etching process.

An interfacial layer is provided that binds a hydrophilic interlayer dielectric to a hydrophobic gap-filling dielectric. The hydrophobic gap-filling dielectric extends over and fill gaps between devices in an array of devices disposed between two metal interconnect layers over a semiconductor substrate and is the product of a flowable CVD process. The interfacial layer provides a hydrophilic upper surface to which the interlayer dielectric adheres. Optionally, the interfacial layer is also the product of a flowable CVD process. Alternatively, the interfacial layer may be silicon nitride or another dielectric that is hydrophilic. The interfacial layer may have a wafer contact angle (WCA) intermediate between a WCA of the hydrophobic dielectric and a WCA of the interlayer dielectric.

A method includes forming a metallic feature, forming an etch stop layer over the metallic feature, implanting the metallic feature with a dopant, forming a dielectric layer over the etch stop layer, performing a first etching process to etch the dielectric layer and the etch stop layer to form a first opening, performing a second etching process to etch the metallic feature and to form a second opening in the metallic feature, wherein the second opening is joined with the first opening, and filling the first opening and the second opening with a metallic material to form a contact plug.

A semiconductor device structure includes a first conductive layer disposed over a semiconductor substrate, and a second conductive layer disposed over the first conductive layer. The semiconductor device structure also includes a first conductive plug disposed between and electrically connecting the first conductive layer and the second conductive layer. The first conductive plug includes copper. The semiconductor device structure further includes a first lining layer surrounding the first conductive plug. The first lining layer includes manganese.

A semiconductor device includes: a sidewall insulating film; a gate electrode; source and drain regions; a first stress film; and a second stress film.

A semiconductor device includes a gate structure on a substrate, an offset spacer adjacent to the gate structure, a main spacer around the offset spacer, a source/drain region adjacent to two sides of the main spacer, a contact etch stop layer (CESL) adjacent to the main spacer, and an interlayer dielectric (ILD) layer around the CESL. Preferably, a dielectric constant of the offset spacer is higher than a dielectric constant of the main spacer.

A method for forming a semiconductor structure includes forming a gate structure on a substrate; depositing a first dielectric layer over the gate structure; depositing a second dielectric layer over the first dielectric layer and having a different density than the first dielectric layer; performing a first etching process on the first and second dielectric layers to form a trench; performing a second etching process on the first and second dielectric layers to modify the trench; filling a conductive material in the modified trench.