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
Magnetron Sputtering Technology for Microvias Metallization
The increased demand of miniaturized and much more functional electronic devices inspire producers of PCBs (Printed Circuit Boards) to search the new constructions and technologies of manufacturing. Searching for new solutions due to high miniaturization of electronic components is concentrated on increasing density of electronic packaging and using multilayer PCBs. The interconnections between conductive layers are realized by holes with diameter less than 150 μm (microvias). The technologies of metallization of microvias are elaborated (e.g. electroplating), but only in case when aspect ratio is not higher than 1. In the paper we propose metallization of microvias with much more higher aspect ratio. The technological steps which enables metallization of that microvias are as follow: forming of microvias in FR-4 material by Nd:YAG laser drill machine, self-sustained sputtering process, and grown onto the sputtered copper layer. The purpose of our research is to find a combination of magnetron sputter deposition process parameters which guarantee achieving reliable microvia connections.
Investigating the Optical properties of cd1-xznxs thin films deposited by the Dip Technique
A Thesis submitted to the Department of Physics, Kwame Nkrumah University of Science and Technology, in partial fulfillment of the requirement for the degree of 
Master of Science (Solid State Physics)