The current disclosure describes techniques of protecting a metal interconnect structure from being damaged by subsequent chemical mechanical polishing processes used for forming other metal structures over the metal interconnect structure. The metal interconnect structure is receded to form a recess between the metal interconnect structure and the surrounding dielectric layer. A metal cap structure is formed within the recess. An upper portion of the dielectric layer is strained to include a tensile stress which expands the dielectric layer against the metal cap structure to reduce or eliminate a gap in the interface between the metal cap structure and the dielectric layer.

A method for forming a FinFET device structure and method for forming the same is provided. The method includes forming an isolation structure over a substrate and forming a first dielectric layer over the isolation structure. The method includes forming a gate structure in the first dielectric layer and forming a deep trench through the first dielectric layer and the isolation structure. The method also includes forming an S/D trench in the first dielectric layer and filling a metal material in the deep trench and the S/D trench to form a deep contact structure and the S/D contact structure. A bottom surface of the S/D contact structure is higher than a bottom surface of the deep contact structure.

An integrated circuit includes a plurality of transistors and an interlevel dielectric layer formed over the transistors. The interlevel dielectric layer includes a first region and a second region with a higher dielectric constant than the first region. The difference in dielectric constant is produced by curing the first region shielding the second region from the curing. Metal signal lines are formed in the first region. Metal-on-metal capacitors are formed in the second region.

In an embodiment, a device includes: a gate structure on a channel region of a substrate; a gate mask on the gate structure, the gate mask including a first dielectric material and an impurity, a concentration of the impurity in the gate mask decreasing in a direction extending from an upper region of the gate mask to a lower region of the gate mask; a gate spacer on sidewalls of the gate mask and the gate structure, the gate spacer including the first dielectric material and the impurity, a concentration of the impurity in the gate spacer decreasing in a direction extending from an upper region of the gate spacer to a lower region of the gate spacer; and a source/drain region adjoining the gate spacer and the channel region.

A semiconductor structure and a method for forming a semiconductor structure are provided. In some embodiments, a method is provided. The method includes following operations. A sacrificial gate structure is formed over a fin structure. The sacrificial gate structure includes a sacrificial gate layer and a sacrificial dielectric layer. The sacrificial gate layer is removed to form a gate trench exposing the sacrificial dielectric layer. A doped region is formed in the fi structure covered by the sacrificial dielectric layer. The sacrificial dielectric layer, a portion of the doped region and a portion of the fin structure are removed from the gate trench. An interfacial layer is formed over the fin structure in the gate trench.

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.

Small sized and closely pitched features can be formed by patterning a layer to have holes therein and then expanding the layer so that the holes shrink. If the expansion is sufficient to pinch off the respective holes, multiple holes can be formed from one larger hole. Holes smaller and of closer pitch than practical or possible may be obtained in this way. One process for expanding the layer includes implanting a dopant species having a larger average atomic spacing than does the material of the layer.

An interconnection structure, along with methods of forming such, are described. The structure includes a dielectric layer, a first conductive feature disposed in the dielectric layer, and a conductive layer disposed over the dielectric layer. The conductive layer includes a first portion and a second portion adj acent the first portion, and the second portion of the conductive layer is disposed over the first conductive feature. The structure further includes a first barrier layer in contact with the first portion of the conductive layer, a second barrier layer in contact with the second portion of the conductive layer, and a support layer in contact with the first and second barrier layers. An air gap is located between the first and second barrier layers, and the dielectric layer and the support layer are exposed to the air gap.

A semiconductor device includes a first dielectric layer disposed over a substrate and a conductive feature, a doped dielectric layer disposed over the first dielectric layer, a first metal portion disposed in the first dielectric layer and in contact with the conductive feature, and a doped metal portion disposed over the first metal portion. The first metal portion and the doped metal portion include a same noble metal material. The doped dielectric layer and the doped metal portion include same dopants. The dopants are bonded to the noble metal material.

A method according to the present disclosure includes receiving a workpiece including a gate structure, a first source/drain (S/D) feature, a second S/D feature, a first dielectric layer over the gate structure, the first S/D feature, the second S/D feature, a first S/D contact over the first S/D feature, a second S/D contact over the second S/D feature, a first etch stop layer (ESL) over the first dielectric layer, and a second dielectric layer over the first ESL, forming a S/D contact via through the second dielectric layer and the first ESL to couple to the first S/D contact, forming a gate contact opening through the second dielectric layer, the first ESL, and the first dielectric layer to expose the gate structure, and forming a common rail opening adjoining the gate contact opening to expose the second S/D contact, and forming a common rail contact in the common rail opening.