A method of attaching a semiconductor chip to a lead frame, including A) providing a semiconductor chip, B) applying a solder metal layer sequence on the semiconductor chip, C) providing a lead frame, D) applying a metallization layer sequence on the lead frame, E) applying the semiconductor chip on the lead frame via the solder metal layer sequence and the metallization layer sequence, and F) heating the arrangement produced under E) to attach the semiconductor chip to the lead frame, wherein the solder metal layer sequence includes a first metallic layer including an indium-tin alloy, a barrier layer arranged above the first metallic layer, and a second metallic layer including gold arranged between the barrier layer and the semiconductor chip.

A method of forming a bonding assembly that includes positioning a plurality of polymer spheres against an opal structure and placing a substrate against a second major surface of the opal structure. The opal structure includes the first major surface and the second major surface with a plurality of voids defined therebetween. The plurality of polymer spheres encapsulates a solder material disposed therein and contacts the first major surface of the opal structure. The method includes depositing a material within the voids of the opal structure and removing the opal structure to form an inverse opal structure between the first and second major surfaces. The method further includes removing the plurality of polymer spheres to expose the solder material encapsulated therein and placing a semiconductor device onto the inverse opal structure in contact with the solder material.

A method of manufacturing a semiconductor device which includes a plurality of members including a semiconductor element is provided. The method may include disposing one surface of a first member which is one of the plurality of members and one surface of a second member which is another one of the plurality of members opposite to each other with a tin-based (Sn-based) solder material interposed therebetween, and bonding the first member and the second member by melting and solidifying the Sn-based solder material. At least the one surface of the first member may be constituted of a nickel-based (Ni-based) metal, and at least the one surface of the second member may he constituted of copper (Cu).

A method of forming a chip assembly may include forming a plurality of cavities in a carrier; The method may further include arranging a die attach liquid in each of the cavities; arranging a plurality of chips on the die attach liquid, each chip comprising a rear side metallization and a rear side interconnect material disposed over the rear side metallization, wherein the rear side interconnect material faces the carrier; evaporating the die attach liquid; and after the evaporating the die attach liquid, fixing the plurality of chips to the carrier.

A method of forming a chip assembly may include forming a plurality of cavities in a carrier; The method may further include arranging a die attach liquid in each of the cavities; arranging a plurality of chips on the die attach liquid, each chip comprising a rear side metallization and a rear side interconnect material disposed over the rear side metallization, wherein the rear side interconnect material faces the carrier; evaporating the die attach liquid; and after the evaporating the die attach liquid, fixing the plurality of chips to the carrier.

Methods for forming bonded assemblies using metal inverse opal and cap structures are disclosed. In one embodiment, a method for forming a bonded assembly includes positioning a substrate against a polymer support that is porous, depositing a metal onto and within the polymer support, disposing a cap layer to the polymer support opposite of the substrate to form a bottom electrode, and removing the polymer support from between the substrate and the cap layer to form a metal inverse opal structure disposed therebetween.

Encapsulated stress mitigation layers and assemblies having the same are disclosed. An assembly that includes a first substrate, a second substrate, an encapsulating layer disposed between the first and second substrates, and a stress mitigation layer disposed in the encapsulating layer such that the stress mitigation layer is encapsulated within the encapsulating layer. The stress mitigation layer has a lower melting temperature relative to a higher melting temperature of the encapsulating layer. The assembly includes an intermetallic compound layer disposed between the first substrate and the encapsulating layer such that the encapsulating layer is separated from the first substrate by the intermetallic compound layer. The stress mitigation layer melts into a liquid when the assembly operates at a temperature above the low melting temperature of the stress mitigation layer and the encapsulating layer maintains the liquid of the stress mitigation layer within the assembly.

An inventive composition and process for formation of a conductive bonding film are disclosed. The invention combines adhesive bonding sheet technologies (e.g. die attach films, or DAFs) with the electrical and thermal conductivity performance of transient liquid phase sintered paste compositions. The invention films are characterized by high bulk thermal and electrical conductivity within the film as well as low and stable thermal and electrical resistance at the interfaces between the inventive film and metallized adherends.

A method of attaching a semiconductor chip on a lead frame includes A) providing a semiconductor chip, B) applying a solder metal layer sequence to the semiconductor chip, wherein the solder metal layer sequence includes a first metallic layer including indium or an indium-tin alloy, C) providing a lead frame, D) applying a metallization layer sequence to the lead frame, wherein the metallization layer sequence includes a fourth layer including indium and/or tin arranged above the lead frame and a third layer including gold arranged above the fourth layer, E) forming an intermetallic intermediate layer including gold and indium, gold and tin or gold, tin and indium, G) applying the semiconductor chip to the lead frame via the solder metal layer sequence and the intermetallic intermediate layer, and H) heating the arrangement produced in G) to attach the semiconductor chip to the lead frame.

An assembly that includes a first substrate, a second substrate, and a stress mitigation layer disposed between the first and the second substrates. The stress mitigation layer is directly bonded onto the second substrate, and the second substrate is separated from the intermetallic compound layer by the stress mitigation layer. The stress mitigation layer has a high purity of at least 99% aluminum such that the stress mitigation layer reduces thermomechanical stresses on the first and second substrates. The assembly further includes an intermetallic compound layer disposed between the first substrate and the stress mitigation layer such that the stress mitigation layer is separated from the first substrate by the intermetallic compound layer.