A method for manufacturing a printed wiring board includes forming a conductor layer including first and second pads on an insulating layer, forming a dry film resist layer on the insulating and conductor layers, forming first and second openings exposing the first and second pads, applying first metal plating to form first and second base plating layers on the first and second pads, applying second metal plating to form a first top plating layer of a first post and portion of a second top plating layer of a second bump post, applying the second metal plating further to form second portion of the second top layer of the second post, removing the dry film resist layer, forming a solder resist layer to cover the first and second posts, and thinning the solder resist layer over entire surface to position the first and second top layers outside the solder resist layer.

A printed wiring board includes a base insulating layer, a conductor layer formed on the base insulating layer and including conductor pads, an underlayer formed on one of the conductor pads of the conductor layer and including a metal different from a metal of the conductor layer, a solder resist layer formed on the base insulating layer such that the solder resist layer is covering the conductor layer and has openings exposing the conductor pads, respectively, and a bump formed directly on a first conductor pad of the conductor pads and including a base plating layer formed in a first opening of the openings and a top plating layer formed on the base plating layer such that a metal of the base plating layer is same as the metal of the conductor layer.

A solder ball assembly can include a first spring element having a first shape and formed from a first elastic electrically conductive material. The solder ball assembly can also include a second spring element having a second shape and formed from a second elastic electrically conductive material. The second spring element is mechanically attached to the first spring element to form a spring assembly. The solder ball can be configured to enclose the spring assembly.

A state detecting device which can be applied even in a severe environment. The state detecting device includes a chargeable all-solid-state battery, a piezoelectric element which supplies charging power to the all-solid-state battery, and an integrated circuit including various sensors which operate with electric power supplied from the all-solid-state battery. The all-solid-state battery, the piezoelectric element, and the integrated circuit are mounted on one surface of a flexible substrate. The flexible substrate is attached to a flexible object which is either an object to be measured or constitutes at least part of an inner surface of a space to be measured.

Methods for refurbishing a circuitry device are disclosed. The methods described herein include applying a first flux to solder contacts connecting a first member of a circuitry device to a second member of the circuitry device; performing a first setting process on the circuitry device with the first flux; applying a second flux to the solder contacts of the circuitry device; performing a second setting process on the circuitry device; and reflowing the solder contacts.

Applying a solderable surface to conductive ink may include partially curing a conductive ink trace; applying, to the partially cured conductive ink trace, a conductive paste comprising conductive particles; and curing the partially cured conductive ink trace and the conductive paste.

A tin or tin alloy plating solution includes: (A) a soluble salt containing at least a stannous salt; (B) an acid selected from an organic acid and an inorganic acid or a salt thereof; (C) a phenyl-based surfactant formed of polyoxyethylene bisphenol ether represented by the General Formula (1); and (D) a leveling agent,

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here, in the Formula (1), X is C.sub.aH.sub.2a (a is 1 or 3) and m is 2 to 12.

A flux includes a rosin resin, an activator, a thixotropic agent, and a solvent. The solvent includes 30% by mass or more and 60% by mass or less monovalent alcohol with respect to a total mass amount of the flux. The monovalent alcohol has 18 or more and 24 or less of carbon atoms in one molecule.

A stackable via package includes a substrate having an upper surface and a trace on the upper surface, the trace including a terminal. A solder ball is on the terminal. The solder ball has a solder ball diameter A and a solder ball height D. A via aperture is formed in a package body enclosing the solder ball to expose the solder ball. The via aperture includes a via bottom having a via bottom diameter B and a via bottom height C from the upper surface of the substrate, where A<B and 0=<C<D. The shape of the via aperture prevents solder deformation of the solder column formed from the solder ball as well as prevents solder bridging between adjacent solder columns.

Apparatus and methods are provided for flexible and stretchable circuits. In an example, a method can include forming a first flexible conductor on a substrate, the first flexible conductor including a first conductive trace surrounded on three sides by a first dielectric, and forming a second flexible conductor on top of the first flexible conductor, the first flexible conductor located between the second flexible conductor and the substrate, the second flexible conductor including a second conductive trace surrounded by a second dielectric.