A method for bonding two superconducting integrated circuits (“chips”), such that the bonds electrically interconnect the chips. A plurality of indium-coated metallic posts may be deposited on each chip. The indium bumps are aligned and compressed with moderate pressure at a temperature at which the indium is deformable but not molten, forming fully superconducting connections between the two chips when the indium is cooled down to the superconducting state. An anti-diffusion layer may be applied below the indium bumps to block reaction with underlying layers. The method is scalable to a large number of small contacts on the wafer scale, and may be used to manufacture a multi-chip module comprising a plurality of chips on a common carrier. Superconducting classical and quantum computers and superconducting sensor arrays may be packaged.

A method for bonding two superconducting integrated circuits (“chips”), such that the bonds electrically interconnect the chips. A plurality of indium-coated metallic posts may be deposited on each chip. The indium bumps are aligned and compressed with moderate pressure at a temperature at which the indium is deformable but not molten, forming fully superconducting connections between the two chips when the indium is cooled down to the superconducting state. An anti-diffusion layer may be applied below the indium bumps to block reaction with underlying layers. The method is scalable to a large number of small contacts on the wafer scale, and may be used to manufacture a multi-chip module comprising a plurality of chips on a common carrier. Superconducting classical and quantum computers and superconducting sensor arrays may be packaged.

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.

Disclosed are examples of integrated circuit (IC) structures and techniques to fabricate IC structures. Each IC package may include a die (e.g., a flip-chip (FC) die) and one or more die interconnects to electrically couple the die to a substrate. The die interconnect may include a pillar, a wetting barrier on the pillar, and a solder cap on the wetting barrier. The wetting barrier may be wider than the pillar. The die interconnect may also include a low wetting layer formed on the wetting barrier.

Disclosed are examples of integrated circuit (IC) structures and techniques to fabricate IC structures. Each IC package may include a die (e.g., a flip-chip (FC) die) and one or more die interconnects to electrically couple the die to a substrate. The die interconnect may include a pillar, a wetting barrier on the pillar, and a solder cap on the wetting barrier. The wetting barrier may be wider than the pillar. The die interconnect may also include a low wetting layer formed on the wetting barrier.

A method for forming a semiconductor structure includes following operations. A first substrate including a first side, a second side opposite to the first side, and a metallic pad disposed over the first side is received. A dielectric structure including a first trench directly above the metallic pad is formed. A second trench is formed in the dielectric structure and a portion of the first substrate. A sacrificial layer is formed to fill the first trench and the second trench. A third trench is formed directly above the metallic pad. A barrier ring and a bonding structure are formed in the third trench. A bonding layer is disposed to bond the first substrate to a second substrate. A portion of the second side of the first substrate is removed to expose the sacrificial layer. The sacrificial layer is removed by an etchant.

A method for forming a semiconductor structure includes following operations. A first substrate including a first side, a second side opposite to the first side, and a metallic pad disposed over the first side is received. A dielectric structure including a first trench directly above the metallic pad is formed. A second trench is formed in the dielectric structure and a portion of the first substrate. A sacrificial layer is formed to fill the first trench and the second trench. A third trench is formed directly above the metallic pad. A barrier ring and a bonding structure are formed in the third trench. A bonding layer is disposed to bond the first substrate to a second substrate. A portion of the second side of the first substrate is removed to expose the sacrificial layer. The sacrificial layer is removed by an etchant.

Embodiments include semiconductor packages and cooling semiconductor packaging systems. A semiconductor package includes a second die on a package substrate, first dies on the second die, conductive bumps between the first dies and the second die, a cold plate and a manifold over the first dies, second die, and package substrate, and first openings in the manifold. The first openings are fluidly coupled through the conductive bumps. The semiconductor package may include a first fluid path through the first openings of the manifold, where a first fluid flows through the first fluid path. The semiconductor package may further include a second fluid path through second openings of the cold plate, where a second fluid flows through the second fluid path, and where the first and second fluids of the first and second fluid paths cool heat providing surfaces of the first dies, the second die, or the package substrate.

Embodiments include semiconductor packages and cooling semiconductor packaging systems. A semiconductor package includes a second die on a package substrate, first dies on the second die, conductive bumps between the first dies and the second die, a cold plate and a manifold over the first dies, second die, and package substrate, and first openings in the manifold. The first openings are fluidly coupled through the conductive bumps. The semiconductor package may include a first fluid path through the first openings of the manifold, where a first fluid flows through the first fluid path. The semiconductor package may further include a second fluid path through second openings of the cold plate, where a second fluid flows through the second fluid path, and where the first and second fluids of the first and second fluid paths cool heat providing surfaces of the first dies, the second die, or the package substrate.

A method of manufacturing a photodetection device, the method includes preparing a light-receiving element including a first main surface including an arrangement of a plurality of first electrodes, forming a first bump containing In on each of the plurality of first electrodes, preparing a circuit substrate including a second main surface including an arrangement of a plurality of second electrodes, forming a second bump containing In on each of the plurality of second electrodes, forming, at at least one of a surface of the first bump or a surface of the second bump, a first oxide film containing In, placing the first main surface and the second main surface so as to face each other, and placing the first bump and the second bump on top of each other with the first oxide film therebetween.