Recent Trend and Future Prospect on Printed Wiring Boards

Personal digital assistants (PDA), such as cellular phones, personal computers and car navigation systems, supporting the ubiquitous society, is expected to be the smart phones which have above mentioned all functions and evolve to ultimate wearable PDAs. High density LSI packaging technologies have been realized the superior performance and function of communication electronics products and printed wiring boards have played very important role to meet these requirements. Here, after brief introduction of the history and the categories, the technologies and the recent trend for the printed wiring boards are introduced, especially focusing on the thermosetting polymer materials. As the future prospect, we pay attention to the automotive electronics field, concretely the power device packaging technologies. High heat resistant and low thermal expansion resins such as polyaromatic epoxy resins, benzoxazine resins and cyanate resins for power semiconductor module are developed. Power semiconductor devices are key devices for carbon dioxide reduction technology. As another approach, the effective use of biomass resources as industrial materials plays an important role. Lignin is a plant biomass and is classified as a polyphenol and investigated a suitable alternative to fossil-fuel-derived phenol resins for use in the thermosetting epoxy resins.