US Patent 7348494 Signal layer interconnects

Inner layer traces on a multilayer printed wiring board are exposed to enable direct interconnection with another device such as a printed wiring board. The traces may be exposed by removing at least some of the dielectric substrate material around the traces, or by extending the traces beyond the other layers of the printed wiring board. Corresponding conductors associated with the other device are placed in direct physical contact with the exposed inner layer traces, and may be aligned and secured with guide plates, alignment pins and spring members. Such direct connection mitigates the need for vias, and has more favorable electrical characteristics for high frequency signal transmission.