A nanowire bonding interconnect for fine-pitch microelectronics is provided. Vertical nanowires created on conductive pads provide a debris-tolerant bonding layer for making direct metal bonds between opposing pads or vias. Nanowires may be grown from a nanoporous medium with a height between 200-1000 nanometers and a height-to-diameter aspect ratio that enables the nanowires to partially collapse against the opposing conductive pads, creating contact pressure for nanowires to direct-bond to opposing pads. Nanowires may have diameters less than 200 nanometers and spacing less than 1 μm from each other to enable contact or direct-bonding between pads and vias with diameters under 5 μm at very fine pitch. The nanowire bonding interconnects may be used with or without tinning, solders, or adhesives. A nanowire forming technique creates a nanoporous layer on conductive pads, creates nanowires within pores of the nanoporous layer, and removes at least part of the nanoporous layer to reveal a layer of nanowires less than 1 μm in height for direct bonding.

A nanowire bonding interconnect for fine-pitch microelectronics is provided. Vertical nanowires created on conductive pads provide a debris-tolerant bonding layer for making direct metal bonds between opposing pads or vias. Nanowires may be grown from a nanoporous medium with a height between 200-1000 nanometers and a height-to-diameter aspect ratio that enables the nanowires to partially collapse against the opposing conductive pads, creating contact pressure for nanowires to direct-bond to opposing pads. Nanowires may have diameters less than 200 nanometers and spacing less than 1 μm from each other to enable contact or direct-bonding between pads and vias with diameters under 5 μm at very fine pitch. The nanowire bonding interconnects may be used with or without tinning, solders, or adhesives. A nanowire forming technique creates a nanoporous layer on conductive pads, creates nanowires within pores of the nanoporous layer, and removes at least part of the nanoporous layer to reveal a layer of nanowires less than 1 μm in height for direct bonding.

A first bonding unit is provided, which includes a first substrate, a first passivation dielectric layer, and first bonding pads. A second bonding unit is provided, which includes a second substrate, a second passivation dielectric layer, and second bonding pads including bonding pillar structures. Solder material portions are formed on physically exposed surfaces of the first bonding pads. The second bonding unit is attached to the first bonding unit by bonding the at least one of the bonding pillar structures to a respective solder material portion.

A microelectronic assembly includes a first substrate having a surface and a first conductive element and a second substrate having a surface and a second conductive element. The assembly further includes an electrically conductive alloy mass joined to the first and second conductive elements. First and second materials of the alloy mass each have a melting point lower than a melting point of the alloy. A concentration of the first material varies in concentration from a relatively higher amount at a location disposed toward the first conductive element to a relatively lower amount toward the second conductive element, and a concentration of the second material varies in concentration from a relatively higher amount at a location disposed toward the second conductive element to a relatively lower amount toward the first conductive element.

A microelectronic assembly includes a first substrate having a surface and a first conductive element and a second substrate having a surface and a second conductive element. The assembly further includes an electrically conductive alloy mass joined to the first and second conductive elements. First and second materials of the alloy mass each have a melting point lower than a melting point of the alloy. A concentration of the first material varies in concentration from a relatively higher amount at a location disposed toward the first conductive element to a relatively lower amount toward the second conductive element, and a concentration of the second material varies in concentration from a relatively higher amount at a location disposed toward the second conductive element to a relatively lower amount toward the first conductive element.

A pre-soldered circuit carrier includes a carrier having a metal die attach surface, a plated solder region on the metal die attach surface, wherein a maximum thickness of the plated solder region is at most 50 μm, the plated solder region has a lower melting point than the first bond pad, and the plated solder region forms one or more intermetallic phases with the die attach surface at a soldering temperature that is above the melting point of the plated solder region.

Various embodiments of the present application are directed towards a method for forming an integrated chip in which a group III-V device is bonded to a substrate, as well as the resulting integrated chip. In some embodiments, the method includes: forming a chip including an epitaxial stack, a metal structure on the epitaxial stack, and a diffusion layer between the metal structure and the epitaxial stack; bonding the chip to a substrate so the metal structure is between the substrate and the epitaxial stack; and performing an etch into the epitaxial stack to form a mesa structure with sidewalls spaced from sidewalls of the diffusion layer. The metal structure may, for example, be a metal bump patterned before the bonding or may, for example, be a metal layer that is on an etch stop layer and that protrudes through the etch stop layer to the diffusion layer.

A three-dimensional stacking technique performed in a wafer-to-wafer fashion reducing the machine movement in production. The wafers are processed with metallic traces and stacked before dicing into separate die stacks. The traces of each layer of the stacks are interconnected via electroless plating.

A semiconductor element bonding structure capable of strongly bonding a semiconductor element and an object to be bonded and relaxing thermal stress caused by a difference in thermal expansion, by interposing metal particles and Ni between the semiconductor element and the object to be bonded, the metal particles having a lower hardness than Ni and having a micro-sized particle diameter. A plurality of metal particles 5 (aluminum (Al), for example) having a lower hardness than nickel (Ni) and having a micro-sized particle diameter are interposed between a semiconductor chip 3 and a substrate 2 to be bonded to the semiconductor chip 3, and the metal particles 5 are fixedly bonded by the nickel (Ni). Optionally, aluminum (Al) or an aluminum alloy (Al alloy) is used as the metal particles 5, and aluminum (Al) or an aluminum alloy (Al alloy) is used on the surface of the semiconductor chip 3 and/or the surface of the substrate 2.

A method of making a semiconductor including soldering a conductor to an aluminum metallization is disclosed. In one example, the method includes substituting an aluminum oxide layer on the aluminum metallization by a substitute metal oxide layer or a substitute metal alloy oxide layer. Then, substitute metal oxides in the substitute metal oxide layer or the substitute metal alloy oxide layer are at least partly reduced. The conductor is soldered to the aluminum metallization using a solder material.