| 摘要 |
PURPOSE:To increase freedom in design, by laminating a plurality of semiconductor chips so that their surfaces face to each other, performing the signal transmission between the chips by light signals between the surface, thereby reducing the area of a light receiving signal, implementing high integration, and potentially isolating the chips. CONSTITUTION:A first chip 1 is mounted on a package 8. A second chip 4 is mounted on the chip 1 with a face down. Bumps 3 and 5 are welded and both chips are wired for current conduction. Then a pad 2 at the peripheral part of the first chip 1 and an inner lead 9, which is formed on the package 8, are bonded by a wire 7. The inner lead 9 is connected to an outer lead 10. The transmission and exchange of signals between the chip are performed by light by using a light emitting element 12 and a light receiving element 13. The first chip 1 constitutes a low speed part and a power source circuit. The second chip 4 constitutes a high speed part. The chip 4 sends and receives the signals to and from the first chip 1 by light. Thus, two chips can be formed by the area for one chip. The area for signal transmission means between the chips can be made smaller than the pad or bumps. The potential between the chips can be freely selected. |
