This invention describes a new process for the selective isolation of through holes in the production of a multi-layer printed circuit card which allows for substantially smaller holes through reference layers to be built, leading to substantially better electrical isolation of signal traces on adjacent...http://www.google.com.au/patents/US5863447?utm_source=gb-gplus-sharePatent US5863447 - Method for providing a selective reference layer isolation technique for the production of printed circuit boards
