Jethro_uk wrote:
On Mon, 22 Feb 2021 20:39:03 +0000, Andrew wrote:

http://www.cpushack.com/2021/02/21/t...-the-birth-of-
overclocking-part-1/

A mixture of pictures and text Brian

Whatever happened to Sinclairs idea of intelligent fault-tolerant wafers
that simply blew the links to duff dies and worked as entire assemblies
of chips ?

Chips have long been fault tolerant - parts get configured based on what
works and what doesn't, and one design is sold as multiple SKUs at different
price points based on functionality and measured performance.

It's easier to manipulate chips rather than wafers though, and they're more
compact. Flash memory chips like micro SD cards are a stack of maybe 32
dice wired together. That's equivalent to a wafer, but you get to throw
away the terrible ones.

Even with all this, keeping everything in a wafer means you're still
susceptible to major faults eg if somewhere on the wafer is a power supply
short you can't just set a configuration bit to disable it.

These days silicon is used like a PCB, and chips are made from a substate of
silicon with wiring and multiple dies (from different fabs/processes) bonded
on top.

The main place we still use wafer scale chips is solar cells, where we
aren't too fussy about minor defects and area counts most of all.

Theo