A 3D semiconductor device, the device including: a first single crystal layer including a plurality of first transistors and at least two metal layers; a plurality of logic gates including the at least two metal layers interconnecting the plurality of first transistors; a plurality of second transistors disposed atop the at least two metal layers; a plurality of third transistors disposed atop the second transistors; a top metal layer disposed atop the third transistors; and a memory array including word-lines, where the memory array includes at least two rows by two columns of memory mini arrays, where each of the mini arrays includes at least four rows by four columns of memory cells, where each of the memory cells includes at least one of the second transistors or at least one of the third transistors, and where at least one of the second transistors include a metal gate.

A 3D semiconductor device, the device including: a first level including a first single crystal layer and first single crystal transistors; a first metal layer; a second metal layer disposed atop the first metal layer; second transistors disposed atop of the second metal layer; third transistors disposed atop of the second transistors, where at least one of the third transistors includes at least one replacement gate, being processed to replace a non-metal gate material with a metal based gate, and where a distance from at least one of the third transistors to at least one of the second transistors is less than 1 micron.

A method for producing a 3D memory device, the method including: providing a first level including a first single crystal layer; forming first alignment marks and control circuits in and on the first level, where the control circuits include first single crystal transistors, where the control circuits include at least two metal layers; forming at least one second level disposed on top of the first level; performing a first etch step within the second level; forming at least one third level disposed on top of the at least one second level; performing a second etch step within the third level; and performing additional processing steps to form a plurality of first memory cells within the second level and a plurality of second memory cells within the third level, where the first memory cells include second transistors, and where the second memory cells include third transistors.

A 3D semiconductor device, the device including: a first level including a first single crystal layer, the first level including first transistors, where the first transistors each include a single crystal channel; first metal layers interconnecting at least the first transistors; and a second level including a second single crystal layer, the second level including second transistors, where the second level overlays the first level, where the second level is bonded to the first level, where the bonded includes oxide to oxide bonds, where the second level includes an array of memory cells, and where each of the memory cells includes at least one recessed-channel-array-transistor (RCAT).

A method is provided. The method includes forming an interconnect structure electrically connected to a semiconductor device; forming a tantalum-based barrier layer over the interconnect structure; oxidizing the tantalum-based barrier layer to form a tantalum oxide over the tantalum-based barrier layer; and forming a metal layer over the tantalum oxide.

A method is provided. The method includes forming an interconnect structure electrically connected to a semiconductor device; forming a tantalum-based barrier layer over the interconnect structure; oxidizing the tantalum-based barrier layer to form a tantalum oxide over the tantalum-based barrier layer; and forming a metal layer over the tantalum oxide.

A method of fabricating an under-bump metallurgy (UBM) structure that is free of gold processing includes forming a titanium layer on top of a far back of line (FBEOL) of a semiconductor. A first copper layer is formed on top of the titanium layer. A photoresist (PR) layer is formed on top of the first copper layer between traces of the FBEOL to provide a cavity to the FBEOL traces. A top copper layer is formed on top of the first copper layer. A protective surface layer (PSL) is formed on top of the top copper layer.

A method for producing a 3D memory device, including: providing a first level including a single crystal layer and control circuits, the control circuits include a plurality of first single crystal transistors; forming at least one second level disposed above the first level; processing to form a plurality of second transistors, where the processing includes forming a plurality of memory cells, each of the plurality of memory cells includes at least one of the plurality of second transistors, where the control circuits control the plurality of memory cells, where at least one of the plurality of memory cells is at least partially atop a portion of the control circuits, where processing the control circuits accounts for a thermal budget associated with processing of the second transistors by adjusting annealing of the first transistors accordingly; processing to replace gate material of at least one of the plurality of second transistors.

A 3D semiconductor device, the device comprising: a first level comprising a first single crystal layer, said first level comprising first transistors, wherein each of said first transistors comprises a single crystal channel; first metal layers interconnecting at least said first transistors; a second metal layer overlaying said first metal layers; and a second level comprising a second single crystal layer, said second level comprising second transistors, wherein said second level overlays said first level, wherein at least one of said second transistors comprises a gate all around structure, wherein said second level is directly bonded to said first level, and wherein said bonded comprises direct oxide to oxide bonds.

A pillar bump structure, and a method for forming the same includes forming, on a semiconductor substrate, a blanket liner followed by a seed layer including a noble metal. A first photoresist layer is formed directly above the seed layer followed by the formation of a first plurality of openings within the photoresist layer. A first conductive material is deposited within each of the first plurality of openings to form first pillar bumps. The first photoresist layer is removed from the semiconductor structure followed by removal of portions of the seed layer extending outward from the first pillar bumps, a portion of the seed layer remains underneath the first pillar bumps.