We have to develop three-dimensional packaging. We have to be able to pack several layers of chips on top of one another and interconnect them. That is being studied, but progress is very slow. The biggest barrier is in the minds of researchers. They are not thinking of new technologies from the manufacturing point of view, and they should.
Many basic problems exist for new manufacturing technology.
If a new device is invented and the technology to manufacture it does not exist, we cannot use it in the marketplace. For example, single-electron transistors have already been demonstrated, but no one knows how to integrate those devices and access information from them. Many basic problems have to be solved in order to utilize single-electron transistors. For example, at NEC we are working on a telephone that can automatically interpret language. So still we have to push.