Abstract: Small, closely spaced deposits of solder materials may be formed with high volumetric accuracy and uniformity of shape by depositing a layer of conductive material over surfaces of a dielectric layer having apertures or recesses (e.g. blind apertures) and conductors and/or pads exposed by those apertures or recesses, masking regions of the conductive material with a further patterned dielectric layer, electroplating solder materials onto regions of the conductive material exposed by the mask, removing the mask and portions of the conductive material by selective etching and reflowing solder away from at least a portion of the surfaces of the apertured dielectric layer. Uniformity of electroplating within blind apertures is enhanced by a combination of fluid jet sparging and cathode agitation. Excess conductor material in the resulting solder deposit can be avoided by replacing conductor material with a constituent component of a solder material in an immersion bath prior to electroplating.

Abstract: A printed circuit board or card for direct chip attachment that includes at least one power core, at least one signal plane that is adjacent to the power core, and plated through holes for electrical connection is provided. In addition, a layer of dielectric material is adjacent the power core and a circuitized conductive layer is adjacent the dielectric material, followed by a layer of photosensitive dielectric material adjacent the conductive layer. Photodeveloped blind vias for subsequent connection to the power core and drilled blind vias for subsequent connection to the signal plane are provided. Also provided is process for fabricating the printed circuit board or card for direct chip attachment.

Abstract: Process is described for applying large quantities of solder to small areas, such as the lands in a high density card, to which it is intended to surface mount electronic devices or directly attach circuitized chips. The land area is temporarily extended by depositing a relatively thin layer of metal beyond the perimeter of the land, wave soldering to deposit excess solder on the extended land region, and reflow, whereby the thin layer of metal dissolves into the solder, causing the solder to retract to the dimensions of the original land. Because the volume of solder is increased, the strength and reliability of the solder joint is greatly improved.

Abstract: The effectiveness of a palladium-tin catalyst for subsequent plating thereon is determined by employing cyclic voltammetry.