New MCM composed of D/L base substrate, high-density-wiring CSP and 3-D Memory Modules : Special issue on high-density packaging technology

An RISC (Reduced Instruction Set Computer) module, which contains secondary cache memories and is called an MCM (Multichip Module) for use in a high-performance workstation, has been developed. The design consists of a D/L (Deposited Organic Thin Film on Laminate) base substrate, a glass-ceramic-based organic-thin-film multilayer build-up CSP (Chip Size Package), and glass-ceramic Three-Dimensional Memory Modules (3DM). The characteristics of this newly developed MCM are as follows. The D/L base substrate has 179 I/O (Input/Output) pins and signal lines of 25-μm width and 50-μm pitch. The CSP carrier signal lines are as fine as those of the D/L, and the CSP carrier features 525 I/O pads and 80-μm diameter chip bonding pads with 108-μm pitch. The 3DM is roughly the same size as a conventional single chip package; with the stacking of ten memory chips in the space of four 3DMs, the area required is roughly only that of four single chip packages.