Making a qubit, the physical device that implements the smallest unit of information in quantum computers, is no simple task. Several types exist, including superconductors, ion traps, and neutral atoms or ions embedded in macromolecules. Not all are equally complex, but they all present significant challenges in production and manipulation. Ideally, the goal is to manufacture qubits on a large scale to enable the development of quantum machines equipped with many more qubits than currently available.
The first step toward this goal was taken by Intel and QuTech, a research institute affiliated with the Technical University of Delft in the Netherlands. At the end of March 2024, they announced the successful industrial production of the first qubit using existing semiconductor manufacturing processes and technology.
Now, however, it is the IMEC (Interuniversity Microelectronics Center), the leading European laboratory in the development of new integration and nanotechnology, that has achieved a significant milestone. They have successfully manufactured a qubit using extreme ultraviolet (EUV) lithography alongside high aperture (High-NA) equipment from ASML, which represents the most advanced integrated circuit manufacturing technology available today.
Caressing the Dream of Industrial Manufacturing of Qubits
IMEC’s main laboratory is located in Leuven, Belgium, and they have worked closely with ASML for over four decades. This collaboration has granted them access to cutting-edge lithography tools from the Dutch company. The qubit produced using ASML’s High-NA equipment is a silicon quantum dot spin type, which is particularly appealing as these types of qubits are seen as the most promising candidates for industrial scaling. According to IMEC, these qubits are often referred to as “the qubits of industry.”
IMEC has shown that the manufacturing of these qubits is largely compatible with the production of CMOS chips.
The pivotal news is IMEC’s confirmation that the manufacturing of these qubits is significantly compatible with the production of integrated circuits using CMOS technology (Complementary Metal-Oxide-Semiconductor). This innovation allows for the potential to manufacture qubits in conventional semiconductor plants. Notably, CMOS technology serves as the foundation for virtually all modern chips.
Sofie Beyne, the project’s director at IMEC, suggests that, “We can leverage decades of semiconductor innovation and repurpose the entire silicon scale-up ecosystem, taking quantum devices beyond laboratory experiments into large-scale, fabricable systems.” Experts believe that the development of machines with millions of qubits will pave the way for error correction technology, often regarded as the holy grail of quantum computing.
Generalizing, silicon quantum dot spin qubits confine an electron within a silicon nanostructure, utilizing the spin state of the trapped electron to store quantum information. This architecture requires that distances between different gates be minimized to reduce environmental noise and minimize errors. Importantly, IMEC has successfully manufactured a network of qubits with spaces of just 6 nm. This nanoscale allows for the theoretical integration of millions of qubits on a single chip.
Image | IMEC
More information | IMEC
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