EUV lithography system for semiconductor manufacturing

A microchip consists of a large number of tiny components. Semiconductor materials form the basis for electronic components. Semiconductors are substances such as silicon, which conduct electrical current very poorly in their normal state. Only when they are heated, irradiated with light, or foreign atoms are introduced does their conductivity increase.

Pure silicon is extracted from quartzite and has advantageous material properties for semiconductor production. A nearly perfect single crystal rod is drawn from molten silicon. This is cut into thin slices (wafers). A thin insulating layer and an additional light-sensitive layer are applied to the wafer. The electronic components beneath its surface are created by specifically introducing other atoms into the wafer. Vapor-deposited conductor tracks connect these elements to each other.

EUV (extreme ultraviolet) light is used to project circuits onto the wafer through a mask. EUV lithography systems are used in semiconductor manufacturing to project extremely fine structures onto wafers. The system uses ultra-short wavelength light. This allows transistors to be manufactured that are significantly smaller than those produced using older processes.

Together with our technology partner Starrag, we have successfully manufactured a highly complex component for an EUV lithography system on a Heckert T45. A lithography system consists of thousands of high-precision aluminum and stainless steel components. The manufacturing requirements are extremely high, as the components are used in a vacuum chamber. 

The requirements for vacuum tightness, purity, precision, and stability make EUV systems so demanding. Only the best machining solutions meet the standards of microchip production.

Various Pokolm premium tools were used in the manufacture of the component for the EUV lithography system. 

The Mirroworx® face milling cutter stands for high surface quality. It was specially developed for the production of absolutely smooth and flat surfaces. Under optimal conditions, mirror-smooth surfaces with surface qualities of Rz < 0.2 µm can be achieved in a short machining time. An additional advantage for the EUV lithography system is that Mirroworx® seals the component surface during machining due to the pressure generated. Mirroworx® thus enabled flawless surfaces to be achieved, which are easy to keep clean thanks to their mirror finish and are vacuum-tight. 

The vibration-damping version of Mirroworx® was used to further improve the surface quality. In addition to its positive impact on surface quality, this variant is gentle on the machine. It reduces spindle wear and prevents tool breakage. 

A solid carbide end mill was used on thin walls. The new “benchmark for thin walls” enables excellent surfaces and accuracies with unmatched performance in the finishing of structural components made of aluminum.

A transistor is a tiny electronic component that acts as a switch or amplifier for electrical signals. It's basically made of semiconductor material that can control the flow of current depending on the voltage applied. Billions of these transistors form the basis of modern microprocessors and memory chips. Thanks to these tiny transistors, computers and smartphones today are super powerful and energy efficient at the same time.

Foreign atoms are introduced into the wafer to adjust its conductivity. The targeted contamination of semiconductors with foreign atoms is called doping. Foreign atoms that have more or fewer outer electrons than the crystal lattice are introduced. The free electron is mobile in the semiconductor, allowing electrical charge to be transported. 

To connect conductor tracks and transistors, metal layers and insulation layers are applied alternately in subsequent steps. The steps of lithography, doping, and layering are repeated dozens of times until the entire chip structure is complete. Finally, the wafer is cut into individual chips, tested, and installed in a housing so that it can later be used in devices.