A support substrate has first electric contacts in a front face. An electronic component is located above the front face of the support substrate and has second electric contacts facing the first electric contacts of the support substrate. An electric connection structure is interposed between corresponding first and second electric contacts of the support substrate and the electronic component, respectively. Each electric connection structure is formed by: a shim that is made of a first electrically conducting material, and a coating that is made of a second electrically conducting material (different from the first electrically conducting material). The coating surrounds the shim and is in contact with the corresponding first and second electric contacts of the support substrate and the electronic component.

A substrate may be included in an electronic device. The substrate may include a first layer that may include a dielectric material. The first layer may define a substrate surface. The substrate may include a second layer optionally including the dielectric material. The second layer may be coupled to the first layer. A wiring trace may be located in the substrate. A recess may extend through the substrate surface, the first layer, and may extend through the second layer. A substrate interconnect may be located within the recess. The substrate interconnect may be at least partially located below the substrate surface. The substrate interconnect may be in electrical communication with the wiring trace.

A method of forming solder bumps includes preparing a substrate having a surface on which a plurality of electrode pads are formed, forming a resist layer on the substrate, the resist layer having a plurality of openings, each of the openings being aligned with a corresponding electrode pad of the plurality of electrode pads, forming a conductive pillar in each of the openings of the resist layer, forming conductive layers to cover at least side walls of the resist layer in the openings to block gas emanating from the resist layer, filling molten solder in each of the openings in which the conductive layers has been formed and removing the resist layer.

A method of forming solder bumps includes preparing a substrate having a surface on which a plurality of electrode pads are formed, forming a resist layer on the substrate, the resist layer having a plurality of openings, each of the openings being aligned with a corresponding electrode pad of the plurality of electrode pads, forming a conductive pillar in each of the openings of the resist layer, forming conductive layers to cover at least side walls of the resist layer in the openings to block gas emanating from the resist layer, filling molten solder in each of the openings in which the conductive layers has been formed and removing the resist layer.

A printed wiring board includes a main substrate and a rising substrate. A support portion of the rising substrate is inserted into a slit in the main substrate. In a direction in which a plurality of first electrodes are aligned, a width of each of the plurality of first electrodes is larger than a width of each of a plurality of second electrodes, and the width of each of the plurality of second electrodes is arranged to fit within the width of each of the plurality of first electrodes.

A method of forming solder bumps includes preparing a substrate having a surface on which a plurality of electrode pads are formed, forming a resist layer on the substrate, the resist layer having a plurality of openings, each of the openings being aligned with a corresponding electrode pad of the plurality of electrode pads, forming a conductive pillar in each of the openings of the resist layer, forming conductive layers to cover at least side walls of the resist layer in the openings to block gas emanating from the resist layer, filling molten solder in each of the openings in which the conductive layers has been formed and removing the resist layer.

A method of fabricating a circuit board structure is provided. The method includes providing a core substrate; forming an insulation layer on the core substrate; forming a patterned metal layer on the insulation layer, wherein the patterned metal layer includes a wiring layer and a pad; forming a first metal pillar on the pad, wherein the first metal pillar has a top surface; and forming a first solder resist layer on the patterned metal layer and the first metal pillar, wherein the first solder resist layer has a first opening exposing the first metal pillar, and the first opening has a bottom surface, wherein the top surface of the metal pillar is higher than or equal to the bottom surface of the first opening.

A support substrate has first electric contacts in a front face. An electronic component is located above the front face of the support substrate and has second electric contacts facing the first electric contacts of the support substrate. An electric connection structure is interposed between corresponding first and second electric contacts of the support substrate and the electronic component, respectively. Each electric connection structure is formed by: a shim that is made of a first electrically conducting material, and a coating that is made of a second electrically conducting material (different from the first electrically conducting material). The coating surrounds the shim and is in contact with the corresponding first and second electric contacts of the support substrate and the electronic component.

A solder ball according to the present invention contains 0.2 to 2.2% by mass of Zn, and a balance of Sn, and has a spherical diameter of 0.1 to 120 m and a yellowness (b*) in an L*a*b* color system of 2.70 or more and 9.52 or less. An oxide film is formed by performing aging treatment. By producing a solder ball having a yellowness of 2.70 or more and 9.52 or less, it is possible to suppress the growth of a Cu.sub.3Sn layer and/or a CuZn(Sn) layer during joining.

A solder ball includes 0.1% by mass or more and 10% by mass or less of In and a remainder of Sn. The ball has a yellowness (b*) in an L*a*b* color system of 2.8 or more and 15.0 or less and a lightness (L*) of 60 or more and 100 or less. The ball further includes at least one element selected from a group of 0% by mass or more and 4% by mass or less of Ag, 0% by mass or more and 1.0% by mass or less of Cu, 0% to 3% by mass in total of Bi and/or Sb, and 0% to 0.1% by mass in total of an element selected from a group of Ni, Co, Fe, Ge, and P, excluding a solder ball including 3% by mass of Ag, 0.5% by mass of Cu, 0.2% by mass of In and a remainder of Sn.