Senior Associate Professor Yukihide Kohira(*1) of the University of Aizu presented the results of collaborative research with the University of Aizu, Tokyo Institute of Technology, and Kioxia Corporation at International Society for Optical Engineering (SPIE) Photomask Technology (*2) in October, 2023 (*3). These findings were featured in Nikkei xTECH (*4) on April 3, 2024.

 In lithography, one of semiconductor manufacturing processes, the optimization of mask pattern shapes is crucial for producing finer semiconductors. The study developed a new optimization method that uses an Ising machine to simulate a quantum annealing computer, one of the implementations of quantum computers, on classical computers. This approach facilitates the creation of mask patterns with high tolerance against process variation.

Lithography process

Mask optimization

(*1) KOHIRA Yukihide Senior Associate Professor

(*2) SPIE Photomask Technology

(*3) Published paper
Yukihide Kohira, Haruki Nakayama, Naoki Nonaka, Tomomi Matsui, Atsushi Takahashi, Chikaaki Kodama, "A formulation of mask optimization into QUBO model for Ising machines", In Proc. SPIE 12751, Photomask Technology, 127511D, 2023. (doi: 10.1117/12.2687615).

(*4) article in NIKKEI xTECH (in Japanese)
Kioxia and others discover that Ising machines thrive in mask optimization