After there is prepared a conductive paste which contains fine copper particles having an average particle diameter of 1 to 100 nm, each of the fine copper particles being coated with an azole compound, coarse copper particles having an average particle diameter of 0.3 to 20 μm, a glycol solvent, such as ethylene glycol, and at least one of a polyvinylpyrrolidone (PVP) resin and a polyvinyl butyral (PVB) resin and wherein the total amount of the fine copper particles and the coarse copper particles is 50 to 90% by weight, the weight ratio of the fine copper particles to the coarse copper particles being in the range of from 1:9 to 5:5, the conductive paste thus prepared is applied on a substrate by screen printing to be preliminary-fired by vacuum drying, and then, fired with light irradiation by irradiating with light having a wavelength of 200 to 800 nm at a pulse period of 500 to 2000 μs and a pulse voltage of 1600 to 3800 V to form a conductive film on the substrate.

Process for producing an electronic subassembly by low-temperature pressure sintering, comprising the following steps: arranging an electronic component on a circuit carrier having a conductor track, connecting the electronic component to the circuit carrier by the low-temperature pressure sintering of a joining material which connects the electronic component to the circuit carrier, characterized in that, to avoid the oxidation of the electronic component or of the conductor track, the low-temperature pressure sintering is carried out in a low-oxygen atmosphere having a relative oxygen content of 0.005 to 0.3%.

Self-sintering conductive inks can be printed and self-sintered with a simple and low-cost process mechanized by exothermic alkali metal and water reaction, with enhanced electrical and thermal performance by liquid metal fusion. Such self-sintering conductive inks may include a gallium-alkali metal component and a water absorbing gel component. After patterning, the self-sintering inks, on reaching a designed trigger temperature (including room temperature), may metallize through a two-step process. Initially the gallium-alkali metal component activates and reacts with water released from the water absorbing gel component. Then the exothermic reaction between the water and the alkali element creates an intense and highly localized heating effect, which liquefies all metallic components in the ink and, on cooling, creates a solid metal trace or interconnect. Post cooling, the metal trace or interconnect cannot be reflowed without a significant temperature increase or other energetic input.

A solution of metal ink is mixed and then printed or dispensed onto the substrate using the dispenser. The film then is dried to eliminate water or solvents. In some cases, a thermal curing step can be introduced subsequent to dispensing the film and prior to the photo-curing step. The substrate and deposited film can be cured using an oven or by placing the substrate on the surface of a heater, such as a hot plate. Following the drying and/or thermal curing step, a laser beam or focused light from the light source is directed onto the surface of the film in a process known as direct writing. The light serves to photo-cure the film such that it has low resistivity.

A method of preparing a conductive pattern on a substrate includes the steps of applying a receiving layer on a substrate, applying a metallic nanoparticle dispersion on the white receiving layer thereby forming a metallic pattern, and sintering the metallic pattern, characterized in that the receiving layer has a roughness Rz between 1 and 75.

Pastes are disclosed that are configured to coat a passage of a substrate. When the paste is sintered, the paste becomes electrically conductive so as to transmit electrical signals from a first end of the passage to a second end of the passage that is opposite the first end of the passage. The metallized paste contains a lead-free glass frit, and has a coefficient of thermal expansion sufficiently matched to the substrate so as to avoid cracking of the sintered paste, the substrate, or both, during sintering.

A power semiconductor substrate comprising an insulating planar base, at least one conductor track and at least one contact area as part of the conductor track, wherein a layer of a metallic material is disposed on the contact area by means of pressure sintering. The associated method comprises the steps of: producing a power semiconductor substrate that includes a planar insulating base, conductor tracks and contact areas; arranging a pasty layer, composed of a metallic material and a solvent, on at least one contact area of the power semiconductor substrate; and applying pressure to the pasty layer.

A biphasic composition comprises a quantity of liquid GaIn and a plurality of solid particles of Ga.sub.2O.sub.3 suspended in the quantity of liquid GaIn, the Ga.sub.2O.sub.3 particles having a median particle size between 8 μm and 25 μm, wherein the volumetric ratio of solid particles of Ga.sub.2O.sub.3 to liquid GaIn is between 0.4 and 0.7. A method of making a biphasic composition of GaIn, a method of making a stretchable circuit board assembly, and a stretchable circuit board assembly are also described.

A circuit board assembly has a circuit board and an electrical component embedded in a cured plastic layer, as well as a heat sink for cooling the component. The component is placed with a first side on a surface of the circuit board facing the heat sink and in electrical contact with the circuit board, and is located in a window in the cured plastic layer. Moreover, the component is materially bonded to a surface of the heat sink facing the circuit board at a second side lying opposite the first side, in particular through soldering or sintering. The plastic layer is injected and cured between the surface of the circuit board and the surface of the heat sink. In the production process, the material is melted by the heat at the same time as the injection, such that the component is materially bonded to the heat sink.

Electrical insulating properties between adjacent copper plates are improved while a defect of a bonded substrate which is caused by concentration of stress to end portions of the copper plates is prevented. A bonded substrate includes a silicon nitride ceramic substrate, a copper plate, and a bonding layer. The copper plate and the bonding layer are disposed on the silicon nitride ceramic substrate. The bonding layer bonds the copper plate to the silicon nitride ceramic substrate. The bonding layer includes: an interplate portion between the silicon nitride ceramic substrate and the copper plate; and a protruding portion protruding from between the silicon nitride ceramic substrate and the copper plate. Exposure of the silicon nitride ceramic substrate is prevented at a position where the protruding portion is disposed.