Abstract: Structures for a waveguide escalator, as well as methods of forming such structures. The structure comprises a first waveguide core on a substrate, a second waveguide core, and a back-end-of-line stack including a third waveguide core disposed between the first waveguide core and the second waveguide core. The third waveguide core comprises a layer stack that includes a first layer, a second layer, and a third layer between the first layer and the second layer. The first layer and the second layer comprise a first dielectric material with a first refractive index, and the third layer comprises a second dielectric material with a second refractive index that is less than the first refractive index.

Abstract: A structure including a barrier-free metal via over a substrate and in a dielectric layer. The structure further includes a barrier-free metal wire in the dielectric layer and over the barrier-free metal via and coupled to at least an exposed portion of the barrier-free metal via. The barrier-free metal via and the barrier-free metal wire each include a non-copper conductor. By using non-copper conductors in the structure, the structure is substantially without liners and has improved performance without creating or increasing parasitic capacitance.

Abstract: A method for hybrid bonding a first semiconductor substrate to a second semiconductor substrate includes forming a first plurality of metal pads on a face of the first substrate, forming a second plurality of metal pads on a face of the second substrate, selectively forming a first dielectric layer over a first insulating material of the first substrate, selectively forming a second dielectric layer over a second insulating material of the second substrate, placing the face of the first substrate against the face of the second substrate so that the first dielectric layer contacts the second dielectric layer, and heating the first substrate and the second substrate to bond the first plurality of metal pads to the second plurality of metal pads. The first and second dielectric layers may be formed by an area selective deposition process.

Abstract: Structures and methods implement an enlarged multilayer nitride waveguide. The structure may include an inter-level dielectric (ILD) layer over a substrate. A first enlarged multilayer nitride waveguide is positioned in the ILD layer in a region of the substrate. A second multilayer nitride waveguide may also be provided in the ILD layer. A lower cladding layer defines a lower surface of the nitride waveguide(s). The lower cladding layer has a lower refractive index than the nitride waveguide(s). Additional lower refractive index cladding layers can be provided on the upper surface and/or sidewalls of the nitride waveguide(s). The enlarged nitride waveguide may be implemented with other conventional silicon and nitride waveguides.

Abstract: A structure includes a through semiconductor via (TSV) in a semiconductor substrate. The structure also includes a cavity including a first cavity portion in the semiconductor substrate and surrounding a middle section of the TSV and in direct contact with the TSV. The cavity also includes a plurality of second cavity portions in the semiconductor substrate and surrounding an upper section of the TSV. The semiconductor substrate is between adjacent second cavity portions, creating a bridge portion that provides structural support. The cavity reduces parasitic capacitance.

Abstract: Embodiments of the disclosure provide a multi-substrate coupling for photonic integrated circuits (PICs). Structures of the disclosure may include a first substrate having a first surface. The first surface includes a groove therein. A second substrate has a second surface coupled to the first surface. The second substrate includes a cavity substantially aligned with the groove of the first surface, and a photonic integrated circuit (PIC) structure horizontally distal to the cavity.

Abstract: Structures including an optical phase shifter and methods of forming a structure including an optical phase shifter. The structure comprises an optical phase shifter including a waveguide core having a first branch and a second branch laterally spaced from the first branch. The structure further comprises a thermoelectric device including a first plurality of pillars and a second plurality of pillars that alternate with the first plurality of pillars in a series circuit. The first plurality of pillars and the second plurality of pillars disposed adjacent to the first branch of the waveguide core, the first plurality of pillars comprises an n-type semiconductor material, and the second plurality of pillars comprises a p-type semiconductor material.

Abstract: Structures for an edge coupler and methods of forming a structure for an edge coupler. The structure comprises a substrate, a dielectric layer over the substrate, and a waveguide core over the substrate. The structure further comprises an airgap that extends at least partially through the dielectric layer and that surrounds a plurality of sides of a portion of the waveguide core.

Abstract: Structures and methods implement an enlarged multilayer nitride waveguide. The structure may include an inter-level dielectric (ILD) layer over a substrate. A first enlarged multilayer nitride waveguide is positioned in the ILD layer in a region of the substrate. A second multilayer nitride waveguide may also be provided in the ILD layer. A lower cladding layer defines a lower surface of the nitride waveguide(s). The lower cladding layer has a lower refractive index than the nitride waveguide(s). Additional lower refractive index cladding layers can be provided on the upper surface and/or sidewalls of the nitride waveguide(s). The enlarged nitride waveguide may be implemented with other conventional silicon and nitride waveguides.

Abstract: Methods of self-aligned multiple patterning. A hardmask is deposited over an interlayer dielectric layer. A mandrel is formed over the hardmask. A block mask is formed that covers a first lengthwise section of the mandrel and that exposes second and third lengthwise sections of the mandrel. After forming the block mask, the second and third lengthwise sections of the mandrel are removed to define a pattern including respective first and second mandrel lines that are separated from each other by the first lengthwise section of the mandrel. The first mandrel line and the second mandrel line expose respective portions of the hardmask, and the first lengthwise section of the mandrel line covers another portion of the hardmask. The pattern is transferred to the hardmask with an etching process, and subsequently transferred to the interlayer dielectric layer with another etching process.

Abstract: In an exemplary method, a first layer is formed on a substrate. First overlay marks are formed in a first zone of the first layer. A non-transparent layer is formed on top of the first layer. At least a portion of the non-transparent layer is removed from an area above the first zone of the first layer. This provides optical access to the first overlay marks. A second layer is formed on top of the non-transparent layer. Second overlay marks are formed in a second zone of the second layer. Position information is obtained from each of the first overlay marks and the second overlay marks.

Abstract: Methods of self-aligned multiple patterning. First and second mandrels are formed over a hardmask, and a conformal spacer layer is deposited over the first mandrel, the second mandrel, and the hardmask between the first mandrel and the second mandrel. A planarizing layer is patterned to form first and second trenches that expose first and second lengthwise portions of the conformal spacer layer respectively between the first and second mandrels. After patterning the planarizing layer, the first and second lengthwise portions of the conformal spacer layer are removed with an etching process to expose respective portions of the hardmask along a non-mandrel line. A third lengthwise portion of the conformal spacer layer is masked during the etching process by a portion of the planarizing layer and defines a non-mandrel etch mask.

Abstract: A method of fabricating interconnects in a semiconductor device is provided, which includes forming an interconnect layer having a conductive line and depositing a first aluminum-containing layer over the interconnect layer. A dielectric layer is deposited over the first aluminum-containing layer, followed by a second aluminum-containing layer deposited over the dielectric layer. A via opening is formed in the second aluminum-containing layer through to the conductive line, wherein the via opening has chamferless sidewalls.

Abstract: A method of fabricating interconnects in a semiconductor device is provided, which includes forming an interconnect layer having a conductive line and depositing a first aluminum-containing layer over the interconnect layer. A dielectric layer is deposited over the first aluminum-containing layer, followed by a second aluminum-containing layer deposited over the dielectric layer. A via opening is formed in the second aluminum-containing layer through to the conductive line, wherein the via opening has chamferless sidewalls.

Abstract: Methods of fabricating an interconnect structure. A hardmask is deposited over an interlayer dielectric layer, and a block mask is formed that covers an area on the hardmask. A sacrificial layer is formed over the block mask and the hardmask, and the sacrificial layer is patterned to form a mandrel that extends across the block mask.

Abstract: Methods of self-aligned multiple patterning. First and second mandrels are formed over a hardmask, and a conformal spacer layer is deposited over the first mandrel, the second mandrel, and the hardmask between the first mandrel and the second mandrel. A planarizing layer is patterned to form first and second trenches that expose first and second lengthwise portions of the conformal spacer layer respectively between the first and second mandrels. After patterning the planarizing layer, the first and second lengthwise portions of the conformal spacer layer are removed with an etching process to expose respective portions of the hardmask along a non-mandrel line. A third lengthwise portion of the conformal spacer layer is masked during the etching process by a portion of the planarizing layer and defines a non-mandrel etch mask.

Abstract: Methods of self-aligned multiple patterning. A hardmask is deposited over an interlayer dielectric layer. A mandrel is formed over the hardmask. A block mask is formed that covers a first lengthwise section of the mandrel and that exposes second and third lengthwise sections of the mandrel. After forming the block mask, the second and third lengthwise sections of the mandrel are removed to define a pattern including respective first and second mandrel lines that are separated from each other by the first lengthwise section of the mandrel. The first mandrel line and the second mandrel line expose respective portions of the hardmask, and the first lengthwise section of the mandrel line covers another portion of the hardmask. The pattern is transferred to the hardmask with an etching process, and subsequently transferred to the interlayer dielectric layer with another etching process.

Abstract: In an exemplary method, a first layer is formed on a substrate. First overlay marks are formed in a first zone of the first layer. A non-transparent layer is formed on top of the first layer. At least a portion of the non-transparent layer is removed from an area above the first zone of the first layer. This provides optical access to the first overlay marks. A second layer is formed on top of the non-transparent layer. Second overlay marks are formed in a second zone of the second layer. Position information is obtained from each of the first overlay marks and the second overlay marks.

Abstract: In an exemplary method, a first layer is formed on a substrate. First overlay marks are formed in a first zone of the first layer. A non-transparent layer is formed on top of the first layer. At least a portion of the non-transparent layer is removed from an area above the first zone of the first layer. This provides optical access to the first overlay marks. A second layer is formed on top of the non-transparent layer. Second overlay marks are formed in a second zone of the second layer. Position information is obtained from each of the first overlay marks and the second overlay marks.

Abstract: Methods of fabricating an interconnect structure. A hardmask is deposited over an interlayer dielectric layer, and a block mask is formed that covers an area on the hardmask. A sacrificial layer is formed over the block mask and the hardmask, and the sacrificial layer is patterned to form a mandrel that extends across the block mask.