300MM wiring enabling 28Gbps transmission on LCP board (PALAP)

Recent cloud computing communication strongly requires an order of magnitude higher bandwidth. For example, the maximum rate prescribed for SerDes and Interlaken is 28Gbps. This trend can be observed in new enterprise servers or enterprise routers. Boards and cards for enterprise devices are often relatively large, e.g., 300mm × 500mm, with more than 60 layers. Fine pitch wiring of over 300mm length is therefore needed in each layer. We have developed an LCP board with 28Gbps bandwidth along with a 300mm wiring length, 100um width and 380um pitch, to be described in detail. The board can be produced using DENSO's PALAP process, which is useful for high-density solutions involving more than 100 layers.