59 In 2025, the number of transistors in a commercially available microprocessor was over 100 billion. Do you know what other devices contain microchips? Wafers are generally 0.1 inches thick discs and their diameter ranges from 4 to 8 inches. An inch is 2.54 centimetres. MICROCHIPS Every microprocessor inside an electronic device is made up of microchips. These are very small integrated circuits that can contain billions of transistors on a tiny silicon chip . Microchips are designed to collect and store data and to transmit it in a fast and easy way. They are used in GPS systems, credit cards, ID cards, and for the identification of pets . The making of a microchip Making a microchip is a complex manufacturing process that requires great precision. Microchips are built using silicon, which is made out of sand. Silicon must be chemically treated to reach 99.999% purity to eliminate all the impurities that could cause damage. The silicon is then melted and shaped into ingots. dice: dadi to encase: racchiudere etching: incisione ingot: lingotto pattern: modello to slice: affettare smooth: liscio tiny: minuscolo The ingots are sliced into very small and thin wafers , which are polished to become as smooth as mirrors. Some layers are added to the wafer to build circuits on them, and they are covered by a solution called photoresist that reacts to light. Through a process called photolithography, the layers are exposed to ultraviolet light to imprint the pattern of the microchip onto each of them. After the etching through photolithography, the chip is polished, and the silicon components are treated (or doped) with chemicals in order to add or modify their electrical properties. The wafers are then cut into dice and packaged. In the packaging stage, microchips are placed in a protective case which provides the electrical wiring and connections that allow the microchip to be connected to the device it has been produced for. The microchips are tested and encased to protect them from damage. The microchips are then ready to be distributed and used. FRONT-END PROCESSING Cleaning Creating oxide layer Photolithography Etching BACK-END PROCESSING Dicing Chip assembly 134 ELECTRONICS AND ELECTROTECHNOLOGY Packaging Operation test Adding ions