IBM has been actively developing and improving its superconducting chip technology for use in quantum computers. At that time, IBM's most advanced superconducting chip was called the IBM Quantum Hummingbird chip. However, please note that there may have been further advancements or the introduction of newer chips by IBM since then.
The IBM Quantum Hummingbird chip was designed to improve the performance and scalability of IBM's quantum systems. It featured several enhancements compared to its predecessors, including increased connectivity between qubits and improved coherence times. These advancements were aimed at reducing errors and enabling the execution of more complex quantum algorithms.
IBM has been at the forefront of quantum computing research and has made significant contributions to the field. They have developed a series of superconducting chips, each iteration bringing improvements in performance and reliability. To stay up to date with the latest developments from IBM in quantum computing and their superconducting chip technology, I recommend visiting the official IBM Quantum website or referring to their research publications.