High-speed printed circuit board available

Fujitsu Research Institute, Fujitsu Interconnect Technology (FICT), and Fujitsu have jointly developed a printed circuit board that can simultaneously realize 5Gbit/sec high-speed transmission and a 4000-pin GBA package. Mainly for mobile phone base stations and next-generation servers. With an overall size of approximately 600mm x 600mm, it is a large-size multilayer printed circuit board that can be stacked in more than 20 layers. The FICT will begin sampling in June 2004 and will supply it in volume in December of the same year. The sales target for 2005 is set at 2 billion yen (about 154 million yuan).
According to the assumption, the circuit board used for the base station equipment will have a transmission speed of 5 Gbit/s in 2005, and the number of pins on the circuit board will reach 4,000 (with an interval of 0.8 mm). Moreover, "Transmission Loss at 5 Gbit/s speed must be controlled at -8 dB or more" (Mitada Taibo, Principal Researcher, Institute of Materials and Environmental Technology, Fujitsu Research Institute). In the past, it was not enough to achieve a transmission loss of -8 dB or more by changing the interlayer insulation material alone, and since it was impossible to increase the density after thick wiring, new measures must be taken.
Fujitsu Research Institute adopted the high-speed transmission layer in the middle layer of the circuit board, and the surface of the circuit board took on the role of a high-density layer, achieving high speed and high density at the same time. High-speed layers and high-density layers are pre-made in production, and they are finally glued together. Compared with the laminating method, the production cycle can be reduced by half, and since only qualified products can be stacked, the yield can be improved. In addition, the accuracy of the module is improved by measuring the transmission loss of the actual wiring, so the design and trial production only need half of the original time.