InterChip Systems, Inc. - 3 Case Studies

 

InterChip has conducted three case studies on 3D MCM technologies using Thomson's MCM-V technology [12], which uses `Direct laser write traces on epoxy cube face' for vertical interconnections as discussed in section . In these cases, chips are aligned with one another, then molded into rectangular blocks, and interconnected with traces along the sides of the 3D MCM. The three case studies are:

1. Large Main Memory: This is a 256 Mbyte memory with error correction that resides on 6 boards along with four processor nodes, network functions, and other circuitry. For risk and economy reasons, TSOP memory chips were used instead of bare dice. The 3D design implementation of the main memory was achieved by using five 3D MCM DRAM banks, and each MCM contains 7 memory chips.
2. Intelligent Artillery Shells: This system was implemented using 3D MCM technonology that uses bare die to add intelligence to munitions such as 155 mm howitzer shells, submunitions, and small rockets. The electronic requirements for this application are:
   • to function (albeit briefly) after the shell's impact;
   • to be able to withstand high acceleration, both positive and negative, to 100,000 g's;
   • good electrical contacts at all times;
   • minimise the size;
   • easy to both install and replace.
   The electronic system for the artillery shell is designed to have a cylindrical shape that fits inside a cavity. One side of the cylinder is flattened to provide a surface for electrical connections via pressure contacts where the chips are arranged parallel to the axis of the cylinder.
3. Security Device: The 3D MCM technology was used in the design of an electronic module that adds a security function to a variety of products such as cars, car radios, televisions, and computers. The modules were designed using a bare dice stacking approach. The modules, when activated remotely, deactivate stolen items and report their locations to aid the retrieval of stolen property. The module contains 3 sections, each implemented in a custom integrated circuit. These sections are:
   • A communications function; essentially a stripped down pager or cellular phone.
   • A security identification unit to authorise product deactivation and location reporting.
   • A unit location function.

   The main requirements of the module are:

   • Minimum size
   • Low cost
   • High frequency operation
   • Electrical shielding
   • Protection against disassembly and/or reverse engineering