In an embodiment, a method includes: stacking a plurality of first dies to form a device stack; revealing testing pads of a topmost die of the device stack; testing the device stack using the testing pads of the topmost die; and after testing the device stack, forming bonding pads in the topmost die, the bonding pads being different from the testing pads.

A pillar structure, and a method of forming, for a substrate is provided. The pillar structure may have one or more tiers, where each tier may have a conical shape or a spherical shape. In an embodiment, the pillar structure is used in a bump-on-trace (BOT) configuration. The pillar structures may have circular shape or an elongated shape in a plan view. The substrate may be coupled to another substrate. In an embodiment, the another substrate may have raised conductive traces onto which the pillar structure may be coupled.

A package comprising a substrate and an integrated device coupled to the substrate through a plurality of pillar interconnects and a plurality of solder interconnects. The plurality of pillar interconnects includes a first pillar interconnect comprising a first cavity. The plurality of solder interconnects comprises a first solder interconnect located in the first cavity of the first pillar interconnect. A planar cross section that extends through the first cavity of the first pillar interconnect may comprise an O shape. The first pillar interconnect comprises a first pillar interconnect portion comprising a first width; and a second pillar interconnect portion comprising a second width that is different than the first width.

An amplifier IC mounted on a multilayer board includes input, output, and common terminals. The multilayer board includes common, input, and output terminals on board side. These terminals are connected to the corresponding terminals on device side via bumps. On the lower surface of the multilayer board, a lower surface common terminal is arranged at a location overlapping the common terminal in plan view. First, second, and third via conductors are sequentially arranged toward the lower surface common terminal from the common terminal. An input via conductor is connected to the input terminal on board side. In plan view, the area of the first common via conductor is larger than any one of the areas of the second and third common via conductors and the input via conductor. In plan view, the area of bump of the common terminal is larger than the area of bump of the input terminal.

A superconductor thermal filter is disclosed that includes a normal metal layer having a first side, an insulating layer overlying the first side of the normal metal layer, and a multilayer superconductor structure having a first side overlying a side of the insulating layer opposite the side that overlies the normal metal layer. The multilayer superconductor structure is comprised of a plurality of superconductor layers with each superconductor layer having a smaller superconducting energy band gap than the preceding superconductor as the superconductor layers extend away from the normal metal layer. The thermal filter further includes a normal metal layer quasiparticle trap having a first side and a second side with the first side being disposed on a second side of the multilayer superconductor. A bias voltage is applied between the normal metal layer and the normal metal layer quasiparticle trap to remove hot electrons from the normal metal layer.

An embodiment is a structure comprising a substrate, a first die, and a second die. The substrate has a first surface. The first die is attached to the first surface of the substrate by first electrical connectors. The second die is attached to the first surface of the substrate by second electrical connectors. A size of one of the second electrical connectors is smaller than a size of one of the first electrical connectors.

Direct copper-copper bonding at low temperatures is achieved by electroplating copper features on a substrate followed by electroplanarizing the copper features. The copper features are electroplated on the substrate under conditions so that nanotwinned copper structures are formed. Electroplanarizing the copper features is performed by anodically biasing the substrate and contacting the copper features with an electrolyte so that copper is electrochemically removed. Such electrochemical removal is performed in a manner so that roughness is reduced in the copper features and substantial coplanarity is achieved among the copper features. Copper features having nanotwinned copper structures, reduced roughness, and better coplanarity enable direct copper-copper bonding at low temperatures.

A method for forming the conductive layer includes: providing a first conductive film and a solution with a conductive material; coating a surface of the first conductive film with the solution, before performing the coating, a temperature of the first conductive film being lower than an evaporation temperature or a sublimation temperature of the solution; and in a process step of performing the coating or after performing the coating, heating the first conductive film, such that the temperature of the first conductive film is higher than or equal to the evaporation temperature or the sublimation temperature of the solution, and forming a second conductive film covering the surface of the first conductive film, wherein the second conductive film including the conductive material.

A bonded body includes: a first base body including a first wiring, a first electrode made of an electroplating film and including a first surface having a first region covering a periphery of an end portion of the first wiring and a second region covering the end portion of the first wiring, and a first passivation layer made of an insulating material and covering a periphery of the first electrode; a second base body including a second electrode; and solder disposed between the first region of the first electrode and the second electrode.

The connection method between at least two elements (E1, E2) corresponding to a printed circuit (4) and to an electronic component (5), comprises a step of forming a plurality of pad-type stacks (2) of bosses (3), the stacks (2) of bosses (3) being formed on a face (10) of a first (E1) of the elements (E1, E2), the stacks (2) of bosses (3) each comprising the same given number of bosses (3), said method also comprising a step of depositing a brazing product (7) on this first element (E1) provided with stacks (2) of bosses (3), a step of arranging the second (E2) of the elements (E1, E2) on the first element (E1), and a step of remelting the assembly thus formed, in order to obtain an electronic device (1). This method makes it possible to produce a precise and flexible raising of surface mounted electronic components.