An LED wafer includes LED dies on an LED substrate. The LED wafer and a carrier wafer are joined. The LED wafer that is joined to the carrier wafer is shaped. Wavelength conversion material is applied to the LED wafer that is shaped. Singulation is performed to provide multiple LED dies that are joined to a single carrier die. The multiple LED dies on the single carrier die are connected in series and/or in parallel by interconnection in the LED dies and/or in the single carrier die. The singulated devices may be mounted in an LED fixture to provide high light output per unit area. Related devices and fabrication methods are described.

An LED wafer includes LED dies on an LED substrate. The LED wafer and a carrier wafer are joined. The LED wafer that is joined to the carrier wafer is shaped. Wavelength conversion material is applied to the LED wafer that is shaped. Singulation is performed to provide multiple LED dies that are joined to a single carrier die. The multiple LED dies on the single carrier die are connected in series and/or in parallel by interconnection in the LED dies and/or in the single carrier die. The singulated devices may be mounted in an LED fixture to provide high light output per unit area. Related devices and fabrication methods are described.

Direct copper-copper bonding at low temperatures is achieved by electroplating copper features on a substrate followed by electroplanarizing the copper features. The copper features are electroplated on the substrate under conditions so that nanotwinned copper structures are formed. Electroplanarizing the copper features is performed by anodically biasing the substrate and contacting the copper features with an electrolyte so that copper is electrochemically removed. Such electrochemical removal is performed in a manner so that roughness is reduced in the copper features and substantial coplanarity is achieved among the copper features. Copper features having nanotwinned copper structures, reduced roughness, and better coplanarity enable direct copper-copper bonding at low temperatures.

Embodiments include a mixed hybrid bonding structure comprising a composite dielectric layer, where the composite dielectric layer comprises an organic dielectric material having a plurality of inorganic filler material. One or more conductive substrate interconnect structures are within the composite dielectric layer. A die is on the composite dielectric layer, the die having one or more conductive die interconnect structures within a die dielectric material. The one or more conductive die interconnect structures are directly bonded to the one or more conductive substrate interconnect structures, and the inorganic filler material of the composite dielectric layer is bonded to the die dielectric material.

Embodiments include a mixed hybrid bonding structure comprising a composite dielectric layer, where the composite dielectric layer comprises an organic dielectric material having a plurality of inorganic filler material. One or more conductive substrate interconnect structures are within the composite dielectric layer. A die is on the composite dielectric layer, the die having one or more conductive die interconnect structures within a die dielectric material. The one or more conductive die interconnect structures are directly bonded to the one or more conductive substrate interconnect structures, and the inorganic filler material of the composite dielectric layer is bonded to the die dielectric material.

In an embodiment, a package includes a first package structure including a first integrated circuit die having an active side and a back-side, the active side including die connectors, a second integrated circuit die adjacent the first integrated circuit die, the second integrated circuit die having an active side and a back-side, the active side including die connectors, a routing die including die connectors bonded to the active sides of the first integrated circuit die and the second integrated circuit die, the routing die electrically coupling the first integrated circuit die to the second integrated circuit die, an encapsulant encapsulating the first integrated circuit die, the second integrated circuit die, and the routing die, and a first redistribution structure on and electrically connected to the die connectors of the first integrated circuit die and the second integrated circuit die.

In an embodiment, a quantum device includes a first set of protrusions formed on a substrate and a second set of protrusions formed on a qubit chip. In the embodiment, the quantum device includes a set of bumps formed on an interposer, the set of bumps formed of a material having above a threshold ductility at a room temperature range, wherein a first subset of the set of bumps is configured to cold weld to the first set of protrusions and a second subset of the set of bumps is configured to cold weld to the second set of protrusions.

Microelectronic assemblies, and related devices and methods, are disclosed herein. For example, in some embodiments, a microelectronic assembly may include a photonic receiver; and a die coupled to the photonic receiver by interconnects, wherein the die includes a device layer between a first interconnect layer of the die and a second interconnect layer of the die. In still some embodiments, a microelectronic assembly may include a photonic transmitter; and a die coupled to the photonic transmitter by interconnects, wherein the die includes a device layer between a first interconnect layer of the die and a second interconnect layer of the die.

A multi-chip unit suitable for chip-level packaging may include multiple IC chips that are interconnected through a metal redistribution structure, and that are directly bonded to an integrated heat spreader. Bonding of the integrated heat spreader to the multiple IC chips may be direct so that no thermal interface material (TIM) is needed, resulting in a reduced bond line thickness (BLT) and lower thermal resistance. The integrated heat spreader may further serve as a structural member of the multi-chip unit, allowing a second side of the redistribution structure to be further interconnected to a host by solder interconnects. The redistribution structure may be fabricated on a sacrificial interposer that may facilitate planarizing IC chips of differing thickness prior to bonding the heat spreader. The sacrificial interposer may be removed to expose the RDL for further interconnection to a substrate without the use of through-substrate vias.

A multi-chip unit suitable for chip-level packaging may include multiple IC chips that are interconnected through a metal redistribution structure, and that are directly bonded to an integrated heat spreader. Bonding of the integrated heat spreader to the multiple IC chips may be direct so that no thermal interface material (TIM) is needed, resulting in a reduced bond line thickness (BLT) and lower thermal resistance. The integrated heat spreader may further serve as a structural member of the multi-chip unit, allowing a second side of the redistribution structure to be further interconnected to a host by solder interconnects. The redistribution structure may be fabricated on a sacrificial interposer that may facilitate planarizing IC chips of differing thickness prior to bonding the heat spreader. The sacrificial interposer may be removed to expose the RDL for further interconnection to a substrate without the use of through-substrate vias.