Concept and basic technologies for 3-D IC structure

VLSI will be rearching to limit of minimization in 1990´s, and after that, further increase of packing density or a number of transistors in a chip might depend on the vetical integration (3-D IC) technology. The 3-D IC consisting of completely stacked active layers offers the flexibility of the circuit design and ccmposition of various devices. This will lead upto new system design and novel functional device. It will become a big trend for VLSI in the next generation.