Ultra-fine conductor technology

The ever more progressive miniaturisation of electronic assemblies is increasingly determining the development of circuit board technology. The structure and connection technologies being deployed in assembly production are characterised by the increasing utilisation of µBGA (Micro Ball Grid Arrays), FC (Flip Chip) and CSP (Chip Scale Packages) elements. These place heightened demands both on the circuit board structures of the circuit substrate and on the connection technologies.

This is where the future technologies besides structures of line/space less than 50/50 µm will also increasingly necessitate redistribution solutions with staggered and stacked micro-via technologies. KSG Leiterplatten GmbH is meeting this challenge through the continuous development of existing technologies within the scope of development projects and drawing on its plant and material suppliers.

An example here is the results in the BMBF (Federal Ministry of Education and Research) research project on “bonding procedures and process techniques for ultra-fine pitch assemblies (ProUFP for short)” in which KSG Leiterplatten GmbH successfully demonstrated the structuring of conductive patterns in the fine pitch range of less than 50 µm with optimised conductive pattern-creating processes by using standard materials. The introduction of the Cu filling technology for layouts which necessitate the insertion of stacked micro-vias took place within the scope of an internal technology project.

Schliff 1

Micrograph section 50 µm geometries in the end state


Photoresist resolution


An example of circuit board solutions based on assembly miniaturisation: redistribution with stacked micro-vias over 4 levels