Advanced via filling for improved within-unit distribution

Laser drilling of blind micro vias (BMV's) and subsequent copper filling is now the standard manufacturing technique for high density interconnects. To enable the required interconnect density and to provide the surface for reliable solder attachment in IC packaging these copper filled BMV's are used. To maintain the development in circuit miniaturization together with the reduction in overall processing costs as expected by Moore's Law and to meet the demand for ever more filled BMV's on each plated layer, advances in filling processes are required. The filling processes used for a stable production must provide void/inclusion free filling and a minimum of surface plated copper. For the production of the finest lines and spaces for IC substrate technology additives that allow the use of pattern plating in the semi additive process (SAP) to produce structures in the range of 10 μm line and space are available. As the force for miniaturization of consumer electronics continues, even finer lines and spaces are required. Challenges like within-unit distribution become a critical factor for the subsequent processing steps. Modifications in the production process as well as development of new additives show that Moore's Law is still valid.