EUV: How the Next Generation of Chips is Made

Many times you may have read that a chip manufacturing node is defined as “n” nm EUV, but what do these acronyms mean? How is an EUV node different from a non-EUV node? What limitations and advantages do these processes have? Are all the processes of the future going to be EUV?

Chip manufacturers such as Intel, TSMC, Samsung, UMC, etc., are continuously developing new processes that allow them to create chips with a greater number of transistors, EUV lithography being one of the technologies they have adopted to achieve their objectives and the one that is being talked about a lot in recent times.


What do we understand as EUV lithography?


When we talk that a lithographic process is EUV, which means Extreme UltraViolet and therefore it would be translated as Extreme Ultraviolet Lithography, we are referring to the way in which the design of the chips is printed on the wafer at that manufacturing node.

To understand what are the principles of EUV manufacturing nodes we have to introduce the equation formulated by Ernst Abbe, one of the fathers of modern optics, which served to reveal the resolution of a microscope and is expressed as follows way:

d = (λ / 2 * n * sin æ)

Where d is the minimum resolvable distance between two lines, λ is the wavelength, n is the reflective index of the last lens of the microscope , and æ is the open angle of the light cone on the side of the object.

Today what is used in optical lithography is a variation of Abbe’s formula, and it is the one used in chip printing.

CD = k 1 * ((λ / N * A)

In which k 1 is the process factor and is what measures the manufacturing capabilities and NA is the numerical aperture and describes the aperture of the cone of the light beam when it hits the wafer.

Evolución Lambda

When we talk about an EUV lithography, what we mean is that it changes the value of λ at 13.5 nm wavelength, and since the 80’s it has been one of the factors to create increasingly smaller transistors and thus be able to continue the Moore’s Law.

Limitations for implementing extreme ultraviolet lithography

Fabrica de chips

The problem with EUV is that the wavelength used is so short that the light beam is absorbed by most materials and this means that factories have to make the following changes:

  • They have to carry out the production of the wafers in machinery that works under an absolute vacuum.
  • They have to make sure that the photomask is a perfect mirror.

Fotomáscara EUV

A photomask is an opaque plate with holes or transparencies, which allow light to shine through a defined pattern. They are commonly used in photolithography and in the production of integrated circuits (integrated circuits or “chips”) in particular. Think of these as templates like those used by graffiti artists where they cover the parts of the wall that they do not want to be affected by the spray they are using, only that in the case of photomasks they are used for printing chips on a wafer .

Máquina EUV

All this means that, although the manufacturing process using EUV is the future of chip production because it allows the creation of new manufacturing nodes that will in turn allow the creation of chips with a greater number of transistors, its implementation it is extremely expensive and requires special machinery that very few companies in the world can afford.