When/Where/Will PCB Technology Hit a Plateau?

Within one of the presentations last week at the IPC Technology Interchange in Washington D.C., the question was raised of whether printed circuit board technology will reach a plateau or whether it will continue to keep pace with the technological demands and innovations to come.  Restated, the question could be:  as trace widths get smaller, nanotechnology improves, PCB Assembly and demand for greater performance continues to increase – when/where/will PCB technology hit a plateau?

This is a complex question with a large number of factors.  One focus of the discussion could be on the pure technical limitations which will be reached according to the laws of physics, or you may consider the unlikelihood that we will ever meet a need that PCB’s can’t handle due to the high costs which would surround that new technology.

I hope to hear your input and comments.  Where do you see the technology going and needing to innovate?  How do you see system-in-a-package and 3D Integration being a factor?  I don’t even have all of the appropriate questions surrounding this topic, but I hope that the comments below will be full of electronic assembly insight and discussion.