Described examples include methods of fabricating conductive and resistive structures by direct-write variable impedance patterning using nanoparticle-based metallization layers or chemical reaction-based deposition. In some examples, a low conductivity nanoparticle material is deposited over a surface. The nanoparticle material is selectively illuminated at different applied energy levels via illumination source power adjustments and/or scan rate adjustments for selective patterned sintering to create conductive circuit structures as well as resistive circuit structures including gradient resistive circuit structures having an electrical resistivity profile that varies along the structure length. Further examples include methods in which a non-conductive reactant layer is deposited or patterned, and a second solution is deposited in varying amounts using an additive deposition for reaction with the reactant layer to form controllably conductive structures.

A method of manufacturing a printed wiring assembly PWA on a substrate, includes the following steps: receiving assembly data associated with said PWA; dispensing, onto said substrate, and in accordance with the assembly data, a conductive ink; curing the dispensed conductive ink; reducing, by plasma treatment, the cured conductive ink; depositing a solder material on top of at least a portion of the reduced conductive ink; picking and placing, in accordance with the assembly data, one or more components on the deposited solder material; and performing reflow soldering, by heating, of the deposited solder material, the one or more placed components, and the reduced conductive ink, forming an intermetallic compound therebetween.

A temperature sensor can include a resistor, a first electrical contact at a first end of the resistor, a second electrical contact at a second end of the resistor, and a resistance measuring device. The resistor can be formed of a matrix of sintered elemental transition metal particles interlocked with a matrix of fused thermoplastic polymer particles. The resistance measuring device can be connected to the first electrical contact and the second electrical contact to measure a resistance of the resistor.

The present invention relates to methods of treating metal surfaces to enhance adhesion or binding to substrates, and devices formed thereby. In some embodiments of the present invention, methods of achieving improved bonding strength without roughening the topography of a metal surface are provided. The metal surface obtained by this method provides strong bonding to resin layers. The bonding interface between the treated metal and the resin layer exhibits resistance to heat, moisture, and chemicals involved in post-lamination process steps, and therefore can suitably be used in the production of PCB's. Methods according to some embodiments of the present invention are especially useful in the fabrication of high density multilayer PCB's, in particular for PCB's having circuits with line/spacing of equal to and less than 10 microns. Methods according to other embodiments of the present invention are particularly useful in the coating of metal surfaces in a wide variety of applications.

A product article is prepared from a precursor article that has a substrate and a photosensitive thin film or a photosensitive thin film pattern on a supporting side. The product article have an electrically-conductive silver metal-containing film or thin film patterns, each of which contains electrically-conductive metallicsilver obtained by reduction of silver ions in the precursor article, an -oxy carboxylate, an oxime compound, and a photosensitizer that can either reduce reducible silver ions or oxidize the -oxy carboxylate.

A precursor article has a substrate and a photosensitive thin film or a photosensitive thin film pattern on a supporting side. The photosensitive thin film and each photosensitive thin film patterns comprises a non-hydroxylic-solvent soluble silver complex that is represented by the following formula (I):
(Ag.sup.+).sub.a(L).sub.b(P).sub.c (I)
wherein L represents an -oxy carboxylate; P represents a 5- or 6-membered N-heteroaromatic compound; a is 1 or 2; b is 1 or 2; and c is 1, 2, 3, or 4, provided that when a is 1, b is 1, and when a is 2, b is 2. A photosensitizer that can either reduce the reducible silver ion or oxidize the -oxy carboxylate having a reduction potential can also be present. Such precursor articles can be irradiated with UV-visible radiation to reduce the silver ions to provide electrically-conductive metallic silver in thin films or thin film patterns in product articles or devices.

A one-step react-on-demand (RoD) method for fabricating flexible circuits with ultra-low sheet resistance, enhanced safety and durability. With the special functionalized substrate, a real-time three-dimensional synthesize of silver plates in micro scale was triggered on-demand right beneath the tip in the water-swelled PVA coating, forming a three-dimensional metal-polymer (3DMP) hybrid structure of 7 m with one single stroke. The as-fabricated silver traces show an enhanced durability and ultralow sheet resistance down to 4 m/sq which is by far the lowest sheet resistance reported in literatures achieved by direct writing. Meanwhile, PVA seal small particles inside the film, adding additional safety to this technology. Since neither nanomaterials nor a harsh fabrication environment are required, the proposed method remains low-cost, user friendly and accessible to end-users. the RoD approach can be extended to various printing systems, offering a particle-free, sintering-free solution for high resolution, high speed production of flexible electronics.

Provided is a novel printing process for fabricating metallic, conductive and transparent ultra-thin nanowires and patterns including same on a substrate. The process includes two different controllable steps, each designed to achieving a useful and efficient pattern.

Provided is a method for fabricating a strain-pressure complex sensor and a sensor fabricated thereby. This method includes coating a fabric with a graphene oxide; reducing the graphene oxide coated with the fabric to form a graphene; disposing carbon nanotubes on the fabric coated with the graphene; and connecting an electrode to the fabric.

There is provided a roughened copper foil which can significantly improve adhesion to an insulating resin and reliability (e.g., hygroscopic heat resistance). The roughened copper foil of the present invention has at least one roughened surface having fine irregularities composed of acicular crystals, wherein the entire surface of the acicular crystals is composed of a mixed phase of Cu metal and Cu.sub.2O.