What is etching in IC manufacturing

microchip abc

We met Hagen Rötz at Infineon Technologies in Dresden. He explained to us how an integrated circuit is created from a silicon wafer (the English name is Integrated Circuit - IC)

Infineon Technologies operates two chip factories in the Saxon capital. When I visit the company, a young man is waiting for me at the entrance: Hagen Rötz is one of the Infineon employees who take care of quality assurance in chip production. To do this, he looks at chips that have just come out of production under the microscope - measures their structures and sends the measurement results back to the production departments. Today, Hagen will show me Infineon and explain how an integrated circuit is made on a tour of the chip factory.

How small are 90 nanometers?

The first stop on the tour is Hagen's laboratory. There he shows me the picture of a chip that he is using a transmission electron microscope (TEM) appraised. On the picture you can see dark gray spheres that form a pattern. The spheres have no sharp outlines - they resemble shadow structures. "These are silicon atoms," says Hagen. 'Wow!' I think. As a person interested in physics, I tried to imagine atoms. It is new to me that there are microscopes that can make atoms visible! But I am even more amazed when Hagen explains the pictures to me. "The picture shows the gate of a transistor," he says. “If you look at an integrated circuit from above, the transistor gates are always the narrowest parts of the entire chip. We produce 90 nanometer wide gates here in Dresden. 90 nanometers correspond to a row of 120 atoms in a silicon crystal. That is why we need microscopes with atomic resolution here. Otherwise we wouldn't be able to inspect the gates of our transistors. "

"Can you imagine how small 90 nanometers are?" Asks Hagen. I shake my head. "Neither can I," says Hagen. “Our engineers occasionally try to make comparisons. For example, they say: 90 nanometers is equal to 1,000th the diameter of a human hair. That is true, but it doesn't really give the idea a boost. 90 nanometers are simply beyond the human imagination. "

"When we talk about integrated circuits, there are many other, almost intangible numbers," says Hagen. “In Dresden, for example, we manufacture microprocessors that control motors. Despite being as small as a fingernail, they contain 300 million transistors! Can you imagine that many transistors? ”“ No, ”I admit. “Neither do I,” Hagen agrees again, “but they are actually on the chip. It is a great engineering challenge to manufacture such a product industrially - that means: many thousands of times, inexpensively and absolutely reliably. This is only possible with the latest nanotechnology processes. We use them here - and that's what makes chip manufacturing so exciting. "