Chip stack

The Masonite Wet-Form Process. Masonite Corpor-ation was founded to exploit Mason s patents and still practices the original furnish-preparation process shown schematically in Figure 1. Cooking is accomplished by charging chips into a vertical cylinder outfitted with a slotted plate at the bottom that supports the chip stack. Below the plate is an hydraulically-operated valve that provides passage to the atmosphere. 

Thermally conductive films are used to bond heat dissipating components to heat sinks. Electrically conductive silver-filled epoxy films when used to attach substrates also serve as ground planes and provide RF/EMI shielding. They are also used in the high production automated attachment of leadframes to chips and to bond chips vertically in chip stacks. 

Figure 5.16 Chip stack built up using thermally conductive preform between die layers. ...

Chip stacks. A recent approach to increasing component densities is to connect the die or chip devices vertically as a chip stack instead of assembling them horizontally on a substrate. The silicon chips are first thinned to several mils (2-4 mils), then bonded together. Where the chips are of different sizes, such as an application-specific integrated-circuit (ASIC)... 

Figure 1.15. Cross-section diagrams of chip stacks.

Benkart P, et al. 3D chip stack technology using through-chip interconnects. IEEE Des Test Compnt 2005. 

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