Motorola Defense Division classified large-format chip bonding

Early-1990s DoD program at Motorola making 1–2 inch chips with integrated functions to circumvent the gigahertz signal-distance limit. Tom uses it to illustrate the cost of staying in a small-chip regime once parasitic delays become limiting.

Except it didn't keep going up. Back in the early '90s, the defense department made some 2-inch chips that were 1 to 2 inches on a side, where they were integrating everything all on one chip to beat this time limitation of the gigahertz, because it still takes time, you've got parasitic capacitances. You can't go 3 GHz from one corner of this board to the other corner. If you're going to be operating at 3 GHz, you've got to do everything in a very small area. The classified military chips at the time were manufactured at Motorola, who had a facility that was about 10% of their business, and all they did was make classified military electronics, special chips for the military.

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Classified counterexample to the 1 cm limit: in the mid-90s DoD made 1- to 2-inch chips because they needed short interconnect distances for speed. Tom uses this to mark the limit of what strain energy permits.

That's not to say that back in the mid-90s the Defense Department didn't make chips that were an inch or two on a side — but this was all super-classified military stuff, where the interconnect distance had to be small enough to get the speeds they wanted. As they've downsized the chips, that technology has gone away. They don't need to do that. But these were some of the things that Motorola's defense division was doing for the Department of Defense — really pushing well beyond the limits in terms of dimensions you can bond.