A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.

A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.

A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.

A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.

A semiconductor package structure includes a semiconductor die surface having a narrower pitch region and a wider pitch region adjacent to the narrower pitch region, a plurality of first type conductive pillars in the narrower pitch region, each of the first type conductive pillars having a copper-copper interface, and a plurality of second type conductive pillars in the wider pitch region, each of the second type conductive pillars having a copper-solder interface. A method for manufacturing the semiconductor package structure described herein is also disclosed.

A semiconductor package structure includes a semiconductor die surface having a narrower pitch region and a wider pitch region adjacent to the narrower pitch region, a plurality of first type conductive pillars in the narrower pitch region, each of the first type conductive pillars having a copper-copper interface, and a plurality of second type conductive pillars in the wider pitch region, each of the second type conductive pillars having a copper-solder interface. A method for manufacturing the semiconductor package structure described herein is also disclosed.

A semiconductor package of a pin-grid-array type includes a bump pad on a first substrate, a metal socket on a second substrate, a core material for reverse reflow on the bump pad, and solder paste or a solder bump forming a solder layer on the core material for reverse reflow. The solder paste or the solder bump is in contact with the bump pad. The core material for reverse reflow and the solder paste or the solder bump bonded to the core material for reverse reflow are used as a pin and detachably attached to the metal socket. The core material for reverse reflow includes a core, a first metal layer directly coated on the core, and a second metal layer directly coated on the first metal layer.

A semiconductor package of a pin-grid-array type includes a bump pad on a first substrate, a metal socket on a second substrate, a core material for reverse reflow on the bump pad, and solder paste or a solder bump forming a solder layer on the core material for reverse reflow. The solder paste or the solder bump is in contact with the bump pad. The core material for reverse reflow and the solder paste or the solder bump bonded to the core material for reverse reflow are used as a pin and detachably attached to the metal socket. The core material for reverse reflow includes a core, a first metal layer directly coated on the core, and a second metal layer directly coated on the first metal layer.

A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.

A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.