Trends in Three-Dimensional Integration

VLSI will be reaching to the limit of minimization in the 1990s, and after that, further increase of packing density or functions night depend on the vertical integration technology and wafer scale integration. The 3-D ICs consisting of completely stacked active layers offers the flexibility of circuit design and composition of various devices. Three-dimensional (3-D) integration is expected to provide several advantages, such as 1) parallel processing, 2) high-speed operation, 3) high packing density, and 4) multifunctional operation. This will lead upto new system design and the novel functional device. It will become a big trend for VLSI in the next generation.