The semiconductor manufacturing industry is vast, complex, dynamic, and on the very edge of technological innovation. It is the facilitator of our modern digital world, from smartphones to MRI machines, cookers to space shuttles, everything these days is powered by semiconductor chips, the brain of every circuit board. The demand is high, very high, and to keep up with this, companies, such as Samsung, TSMC, Onsemi and Texas Instruments, produce over 1 trillion semiconductor chips each year, that’s enough for every person on the planet to receive 150 chips each, every 365 days! With such high demand and vast quantities produced, there is a strict requirement for absolute precision and efficiency from the manufacturing process, and this procedure isn’t simple in the slightest.
A chip is made up of a silicon base containing billions of transistors, electronic switches, and a vast network of nanowires within an insulator substrate. To manufacture these, a contaminant-free environment is essential as even a single dust particle can ruin an entire batch. Production takes place in factory-sized clean rooms and follows a multi-step process that begins with a polished silicon wafer sliced from a pure silicon ingot. Wafers are moved from machine to machine for each step of the process via an automated overhead transport system, to prevent contamination. In the first stage, a layer of non-conducting silicon dioxide is applied as an insulator, followed by a light-sensitive photoresist solution. UV light is passed through a stencil and miniaturised by lenses, which hardens the exposed photoresist, allowing the unexposed area to be washed away leaving a microscopic mask of the stencil, in a process called photolithography. The underlying exposed silicon dioxide is then etched away by hot gases, the mask is removed and a metal layer, usually copper or aluminium, is applied to fill the gaps. This is planned back to the SO2 level leaving nano tracks of metal. This process is repeated 80 times over 12 weeks for an 80-layer chip. Finally, the wafer is laser-cut into individual chips, which are tested using ATE machines, to determine their computational capabilities and application.
Learn more about this process here.