Quality of PCB Interconnections Based on Blind Microvias Metallized by Magnetron Sputtering Deposition

The magnetron sputtering deposition process to metallize the high aspect ratio (deep/diameter) blind microvias was used. In this technique it is innovative that magnetron sputtering deposition process can be used with self-sustaining mode. This mode allows to deposit of very clear (without any labour gas particles) electro-conductive layers (Radzimski et al., 1998). Typically, the thickness of deposited layers is about few micrometers and with success it can be used as electro-conductive connections. However, the thickness of connections can be grown in electroplating processes to decrease its resistance. In the paper the results of first trials of electro-conductive base-layers growing are presented. The big advantage of magnetron sputtering deposition technique is possibility of increasing the aspect ratio of micro-connections in PCBs (printed circuit boards) even several times. This technique was used successfully for metallization of high aspect ratio blind microvias. It was proved that investigated process can be useful in HDI (high density interconnections) PCBs manufacturing.