A Navajo weaving of an integrated circuit: the 555 timer

Summary

The noted Diné (Navajo) weaver Marilou Schultz recently completed an intricate weaving composed of thick white lines on a black background, punctuated with reddish-orange diamonds. Although this striking rug may appear abstract, it shows the internal circuitry of a tiny silicon chip known as the 555 timer. This chip has hundreds of applications in everything from a sound generator to a windshield wiper controller. At one point, the 555 was the world's best-selling integrated circuit with billions sold. But how did the chip get turned into a rug? The 555 chip is constructed from a tiny flake of silicon with a layer of metallic wiring on top. In the rug, this wiring is visible as the thick white lines, while the silicon forms the black background. One conspicuous feature of the rug is the reddish-orange diamonds around the perimeter. These correspond to the connections between the silicon chip and its eight pins. Tiny golden bond wires—thinner than a human hair—are attached to the square bond pads to provide these connections. The circuitry of the 555 chip contains 25 transistors, silicon devices that can switch on and off. The rug is dominated by three large transistors, the filled squares with a 王 pattern inside, while the remaining transistors are represented by small dots. The weaving was inspired by a photo of the 555 timer die taken by Antoine Bercovici (Siliconinsider); I suggested this photo to Schultz as a possible subject for a rug. The diagram below compares the weaving (left) with the die photo (right). As you can see, the weaving closely follows the actual chip, but there are a few artistic differences. For instance, two of the bond pads have been removed, the circuitry at the top has been simplified, and the part number at the bottom has been removed. A comparison of the rug (left) and the original photograph (right). Dark-field image of the 555 timer is courtesy of Antoine Bercovici. Antoine took the die photo with a dark field microscope, a special typ...