High density memory module

摘要

A memory module is built up from a power distribution assembly in the form of plates forming a capacitor of low inductance and a flexible circuit substrate. The circuit substrate is populated with precisely positioned contact pads for the power, read, write and address lines of memory chips that contact the substrate. Memory chips are fixed to heat spreaders and loaded into a chip holder which positions the chips for contact with the contact pads on the substrate. The substrate contact pads are plated to form dendritic crystals of palladium and the memory chips are provided with solder balls on the contact pads of the memory chip. The solder balls are held in contact with the contact pads by the compressive forces of clamping a heat sink over the heat spreaders for testing, and the assembly may be readily disassembled to replace any defective memory. The compression connection of the chips to the substrate may be relied on or the solder balls may be reflowed to establish permanent solder connections.