The present invention relates to a method for manufacturing composite solder balls that are metallized on the surface and calibrated, these balls comprising a core consisting of a spherical support particle of diameter Do made of expanded polystyrene and having an intergranular porosity of at least 50%, and a shell covering said support particle and formed by a plurality of metallic surface layers. The present invention also relates to balls that can be obtained by the method according to the invention, as well as to the use thereof for the assembly of electronic boards.

A package base includes a package base body and a bonding metal layer provided in a frame shape or a ring shape in plan view on the package base body, wherein the bonding metal layer contains a Ti—Ag—Cu-containing alloy and a metal belonging to Group 6 in the periodic table.

Disclosed herein are embodiments of lead-free (Pb-free) or lead-bearing solder column devices that can include an inner core, an outer sleeve surrounding a portion of the inner core, at least one space along a length of the outer sleeve, and a second layer including a solder material coupled with a portion of the inner core within the at least one space. The inner core can be configured to support the solder column so as to prevent a collapse of the solder column at temperatures above a liquidus temperature of the outer sleeve's solder material and the second layer's solder material. The column serves as a heat-sink to conduct excessive heat away from a heat generating semiconductor chip. Moreover, the compliant solder column absorbs strain and mechanical stress caused by a difference in the coefficient of thermal expansion (CTE) connecting the semiconductor chip to a printed circuit board (PCB).

The present invention relates to a method for manufacturing composite solder balls that are metallized on the surface and calibrated, these balls comprising a core consisting of a spherical support particle of diameter D.sub.0 made of expanded polystyrene and having an intergranular porosity of at least 50%, and a shell covering said support particle and formed by a plurality of metallic surface layers. The present invention also relates to balls that can be obtained by the method according to the invention, as well as to the use thereof for the assembly of electronic boards.