In the world of semiconductor production, things get smaller all the time. The industry's most famous precept is Gordon Moore's 1975 prediction that the number of transistors squeezed onto a single integrated circuit would continue to double every two years.
It may have been a self-fulfilling prophecy, but Moore's law has proved a surprisingly reliable measure of the industry's evolution. That evolution has led to the development of mind-bogglingly complex devices. The main processor for Microsoft's latest Xbox One X games console, for example, incorporates seven billion transistors on a 359-square-milimeter silicon die. That's 19.5 million transistors per square millimeter. Chip manufacturer Intel has developed chips that it says have 100 million transistors per square millimeter.
Building such intricate devices requires mastery of a host of highly sophisticated techniques and technologies, from materials science to statistical process control. But all modern semiconductor manufacturing processes rely on one major process to create precise features at microscopic scale: photolithography.
Photolithography is simple in principle. A silicon wafer is cleaned, treated and coated with a material know as photoresist. Ultraviolet light is then projected via a mask to create a precise pattern of features on the surface of the photoresist. That light causes a chemical change that allows some parts of the photoresist to be dissolved away with a special developer solution. The surface of the wafer is then etched with liquid or plasma to create the desired features.
The practice, of course, is far more complicated. The manufacture of a complete integrated circuit requires multiple photolithographic steps. The patterns etched onto the wafers must be precisely aligned and perfectly formed. And as the features required on modern chips are just a handful of atoms across, the technology necessary to achieve the required accuracy at production volumes is extraordinarily sophisticated.
The majority of the world's semiconductor makers go to one place for photolithography equipment: Netherlands-based ASML. The 35-year-old firm has an estimated 80 percent market share in the segment. "Our machines drive the shrink of feature sizes that enables the growth of the industry," says Yolanda van Norden, Senior Director of Supply Chain Management Logistic Service Operations at the company.
ASML's day-to-day work involves cutting-edge science and engineering research. Some 85 percent of the company's 16,500 employees are graduates and more than half of them are qualified to master's degree level or higher. The company spends EUR1.1 billion a year on R&D — 16 percent of its turnover — and holds more than 10,000 patents worldwide.