The Long Arc of Semiconductor Scaling

Summary

I planned to write a chiplets explainer this week while traveling to and from CadenceLIVE in San Jose… but I got sucked into the broader chiplets backstory while doing research. After all, chiplets are a semiconductor manufacturing and scaling story of sorts!So I’m pivoting. This post shares the fun historical arc of transistor and IC scaling and concludes with the problems chiplets set out to overcome. A future post will pick up where this leaves off, discussing chiplets and their trade-offs.So sit down, relax, and enjoy the show!The story of semiconductor scaling begins with the earliest discrete transistors, connected to make simple circuits like this:A whopping 3-transistor card used in the IBM 1401 computer. This 1401 computer launched in Oct 1959. SourceNotice how this system has three transistors, each residing in its own package.Although quaint by today’s standards, this transistor-based logic was a welcome replacement for big, unwieldy, unreliable vacuum tubes. Check out this vacuum tube logic circuitry found in an IBM 704, a 1950’s digital computer. Note the vacuum tubes on top:6 vacuum tube module for IBM 704 computer. SourceIt’s honestly a bit shocking to me to imagine this vacuum-based computing even worked! As the University of Waterloo museum recounts, This is a vacuum tube module for the IBM 704 system. You can see of a row of 6 vacuum tubes with a mechanical relay in between them. In later iterations the relay was replaced by two more vacuum tubes for a total of eight. The tubes were part of the logic circuitry. IBM sold the 704 computer from 1954 to 1960. It was a 'scientific' computer, intended for complex calculations, and one of the earliest to use core memory. The FORTRAN and LISP programming languages were originally developed for the IBM 704.LISP and FORTRAN could run on this prehistoric thing? That is WILD!These big vacuum tube systems were unwieldy and unreliable, yet AT&T Bell Labs successfully used them in its telephone systems. That said...