High-Density Mounting Technologies for Printed Circuit Boards in Large-Capacity 3.5-inch HDDs

As a consequence of the increase in data storage capacity on hard disk drives(HDDs), there is a growing need for high-density mounting technologies for printed circuit boards(PCBs) installed in them. In particular, flexible printed circuit boards(FPCs) incorporated in HDDs are facing critical issues including not only severe external restrictions but also the difficulty of mounting preamplifier integrated circuits(ICs) due to the increase in the number of pins and the size of packages. From the standpoints of both quality and productivity in HDD manufacturing, it is therefore necessary to optimize the specifications of FPCs from the conceptual design phase. We have been taking the initiative in developing high-density PCB mounting technologies. We are promoting determination of the specifications of key parts at the initial stage of the design phase and optimization of design in consideration of manufacturing quality, mounting process, and reliability, as well as reliability verification tests. These efforts are making a major contribution to the realization of high-density, high-reliability PCBs suitable. In this report, the process of design and the key technology of high-density mounting have been described.