For most of human history, our inventions and innovations have been at a scale that’s literally easy to grasp. From the largest cathedral to the finest pocket watch, everything that went into our constructions has been something we could see with our own eyes and manipulate with our hands. But in the middle of the 20th century, we started making really, really small stuff: semiconductors. For the first time, we were able to create mechanisms too small to be seen with the naked eye, and too fine to handle with our comparatively huge hands. We needed a way to scale these devices up somewhat to make them useful parts. In short, they needed to be packaged.
We know that the first commercially important integrated circuits were packaged in the now-familiar dual in-line package (DIP), the little black plastic millipedes that would crawl across circuit boards for the next 50 years. As useful and versatile as the DIP was, and for as successful as the package became, its design was anything but obvious. Let’s take a look at the dual in-line package and how it got that way.
Too Many SIgnals
The history of the DIP is shrouded in mystery, which is somewhat unusual for an industry that trumpets innovations far and wide and routinely patents everything. There’s even some doubt as to who the actual inventor or inventors were. The consensus seems to fall on three employees of Fairchild Semiconductor: Don Forbes, Rex Rice, and Bryant “Buck” Rogers, and a credible source, the Computer History Museum, backs up that assertion.
The three are said to have designed the package in 1964, specifically to house new IC dies with ever-increasing numbers of pins needed to support power and signals. Early chips were housed mainly in either TO-5 or TO-18 packages that were more commonly used to package bipolar transistors. The metal cans worked fine for 3-lead devices, but scaling them up to provide more and more connections proved to be limiting. The can could only be made so large, and the radial leads could only be packed so tight. Ten leads were about the practical limit, and that would not support the more complicated chips in the pipeline.
We also know that the Fairchild team’s design is a direct descendant of the ceramic flatpack design that had been developed for the US military as a standard for surface-mount integrated circuits. The package was the brainchild of Yung Tao, a Texas Instruments who devised the ceramic package in 1962. The design of the package was tailored by the military’s need for vibration resistance, a hermetic seal against environmental intrusion, and heat dissipation. The package looks somewhat like a DIP with the leads flattened out into a plane to accommodate surface mounting rather than through-hole mounting.
Leave It to Marketing
We don’t have a lot of literature that reveals the design goals for the DIP, but it’s clear from Fairchild marketing material aimed …read more
Source:: Hackaday