Interconnections in Multilayer PCBs Based on Microvias Metallized by Magnetron Sputtering Deposition
The high advanced miniaturization of electronic components determines designers and producers of PCBs (printed circuit boards) to search the new constructions and technologies of HDI (high density interconnect) PCBs manufacturing. The researches are concentrated on the problems of miniaturization of PCBs interconnections. Many possibilities in this area are created by using microvia technology. The microvias can be made by using several techniques of drilling, but the great problem in this aspect is connected with possibilities of proper and repeatable metallization of microvias. Wide practical techniques of metallization allow to properly metallize of blind microvias which aspect ratio (deep/diameter of microvia) is about 1 or less. In the paper we propose the use of the magnetron sputtering deposition of copper to metallize the high aspect ratio blind microvias. During tests the use of magnetron self-sustaining mode also was investigated. This special mode allow to deposit of thin and very clear (without labour gas particles) electro-conductive layers which can be grown in electroplating processes
Directional copper deposition using dc magnetron self-sputtering
A directional copper deposition process has been developed that uses a dc magnetron source operating in self-sputtering mode. The process is performed at 10−5 Torr range pressure where a “long throw” approach can be utilized without discharge enhancement or mechanical collimation due to a very long mean free path of sputtered species. Magnetron sputtering conditions at which the contact hole filling is promoted and substantially enhanced by the self-sputtering process are illustrated and compared to standard sputtering (i.e., short throw, mTorr pressure) in the presence of argon. The experimental parameters of the new process have been explored by depositing Cu on patterned Si wafers with trenches and contact holes of various aspect ratios.
SR topography of plastically deformed Fe-Si bicrystals - observation in situ and post mortem
SR reflection topography was applied to study the interaction of slip dislocations with the grain boundaries in Fe-4at%Si bicrystals deformed by compression. Three experimental settings with either a white or monochromatic beam were used and the corresponding orientation contrast analysed. Dislocation transmission through the grain boundary was observed in bicrystals with favourable geometry of the slip systems.