3. Interconnection supports

3.1 Principle

Strictly speaking, an interconnection support is a set of insulated conductive lines that represent a pattern of electrical connections between electronic elements within the same sub-assembly. As a rule, the interconnection support also has a purely mechanical holding role for these elements.

Packages interconnect ever denser integrated circuits (with more and more output pads), via interconnect carriers whose relative density is ever lower. In short, packaging is above all a pitch transformer; indeed, the pitches of a semiconductor's output pads are between 35 and 200 µm, whereas the pad pitches used on a printed circuit board are of the order of several tenths of a millimetre for the most common cases. Furthermore, for obvious cost reasons,...