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.

Methods for attachment and devices produced using such methods are disclosed. In certain examples, the method comprises disposing a capped nanomaterial on a substrate, disposing a die on the disposed capped nanomaterial, drying the disposed capped nanomaterial and the disposed die, and sintering the dried disposed die and the dried capped nanomaterial at a temperature of 300° C. or less to attach the die to the substrate. Devices produced using the methods are also described.

Methods for attachment and devices produced using such methods are disclosed. In certain examples, the method comprises disposing a capped nanomaterial on a substrate, disposing a die on the disposed capped nanomaterial, drying the disposed capped nanomaterial and the disposed die, and sintering the dried disposed die and the dried capped nanomaterial at a temperature of 300° C. or less to attach the die to the substrate. Devices produced using the methods are also described.

In a method for connecting components during production of power electronics modules or assemblies, surfaces of the components have a metallic surface layer upon supply, or are furnished therewith, wherein the layer has a surface that is smooth enough to allow direct bonding or is smoothed to obtain a surface that is smooth enough to allow direct bonding. The surface layers of the surfaces that are to be connected are then pressed against each other with a pressure of at least 5 MPa at elevated temperature, so that they are joined to each other, forming a single layer. The method enables simple, rapid connection of even relatively large contact surfaces, which satisfies the high requirements of power electronics modules.

An integrated circuit device wafer includes a silicon wafer substrate and a back side metallization structure. The back side metallization structure includes a first adhesion layer on the back side of the substrate, a first metal later over the first adhesion layer, a second metal layer over the first metal layer, and a second adhesion layer over the second metal layer. The first includes at least one of: silicon nitride and silicon dioxide. The first metal layer includes titanium. The second metal layer includes nickel. The second adhesion layer includes at least one of: silver, gold, and tin. An indium preform is placed between the second adhesion layer and the lid and the indium preform is reflowed.

In an embodiment, a device includes: a bottom integrated circuit die having a first front side and a first back side; a top integrated circuit die having a second front side and a second back side, the second back side being bonded to the first front side, the top integrated circuit die being free from through substrate vias (TSVs); a dielectric layer surrounding the top integrated circuit die, the dielectric layer being disposed on the first front side, the dielectric layer and the bottom integrated circuit die being laterally coterminous; and a through via extending through the dielectric layer, the through via being electrically coupled to the bottom integrated circuit die, surfaces of the through via, the dielectric layer, and the top integrated circuit die being planar.

In an embodiment, a device includes: a bottom integrated circuit die having a first front side and a first back side; a top integrated circuit die having a second front side and a second back side, the second back side being bonded to the first front side, the top integrated circuit die being free from through substrate vias (TSVs); a dielectric layer surrounding the top integrated circuit die, the dielectric layer being disposed on the first front side, the dielectric layer and the bottom integrated circuit die being laterally coterminous; and a through via extending through the dielectric layer, the through via being electrically coupled to the bottom integrated circuit die, surfaces of the through via, the dielectric layer, and the top integrated circuit die being planar.

In an embodiment, a device includes: a bottom integrated circuit die having a first front side and a first back side; a top integrated circuit die having a second front side and a second back side, the second back side being bonded to the first front side, the top integrated circuit die being free from through substrate vias (TSVs); a dielectric layer surrounding the top integrated circuit die, the dielectric layer being disposed on the first front side, the dielectric layer and the bottom integrated circuit die being laterally coterminous; and a through via extending through the dielectric layer, the through via being electrically coupled to the bottom integrated circuit die, surfaces of the through via, the dielectric layer, and the top integrated circuit die being planar.

In an embodiment, a device includes: a bottom integrated circuit die having a first front side and a first back side; a top integrated circuit die having a second front side and a second back side, the second back side being bonded to the first front side, the top integrated circuit die being free from through substrate vias (TSVs); a dielectric layer surrounding the top integrated circuit die, the dielectric layer being disposed on the first front side, the dielectric layer and the bottom integrated circuit die being laterally coterminous; and a through via extending through the dielectric layer, the through via being electrically coupled to the bottom integrated circuit die, surfaces of the through via, the dielectric layer, and the top integrated circuit die being planar.