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.

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.

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.

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.

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.

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.

A method for soldering a die obtained using the semiconductor technique with a leadframe, comprising the steps of providing a leadframe, which has at least one surface made at least partially of copper; providing a die, which has at least one surface coated with a metal layer; applying to the surface a solder alloy comprising at least 40 wt % of tin or at least 50% of indium or at least 50% of gallium, without lead, and heating the alloy to a temperature of at least 380 C. to form a drop of solder alloy; providing a die, which has at least one surface coated with a metal layer; and setting the metal layer in contact with the drop of solder alloy to form the soldered connection with the leadframe. Moreover, a device obtained with said method is provided.

A method for soldering a die obtained using the semiconductor technique with a leadframe, comprising the steps of providing a leadframe, which has at least one surface made at least partially of copper; providing a die, which has at least one surface coated with a metal layer; applying to the surface a solder alloy comprising at least 40 wt % of tin or at least 50% of indium or at least 50% of gallium, without lead, and heating the alloy to a temperature of at least 380 C. to form a drop of solder alloy; providing a die, which has at least one surface coated with a metal layer; and setting the metal layer in contact with the drop of solder alloy to form the soldered connection with the leadframe. Moreover, a device obtained with said method is provided.

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.

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.