Application of Data-Mining to Factor Analysis of Micro-Drilled Hole Quality for Multi-Layer PWBs
Recently, the demand for miniaturization and enhanced performance of printed wiring boards (PWBs) is growing more and more intense with the rapid popularization of information devices. Processing with micro-drills is generally used to make smaller diameter through-holes in PWBs, which are desired for the miniaturization of the equipment. However, the nail heading is one of the problems in the formation of the micro-through-holes. The purpose of this study is to apply a data-mining, which is used to statistically analyze given factors, to the obtained nail heading data of micro-drilled hole walls, and to elucidate the factors that influence the nail heading of the micro-drilled hole walls. The following conclusions were obtained. (1) It was clear that the height of the nail heading was affected by the drill cutting distance of copper foils and the amount of the drill tool wear more than the number of drilling hits or the drill cutting distance of the PWB number of drilled holes. (2) Data-mining was found to be effective to analyze factors which influence on the micro-drilled hole quality in the manufacturing field of PWBs.