Abstract Body

In the semiconductor manufacturing process, there is a robot for moving wafers safely and efficiently. The current situation with this robot is that the moving parts of the robot cause friction and dust which contaminate wafers. Therefore, we have focused on superconductive-assisted machine (SUAM) which makes it possible to levitate wafers and transport them without contact and dust with moving parts. To transport wafers, a stable and sufficient repulsive force and a stable restoring force to withstand lateral movement are required. In our previous work [1][2], SUAM with superconducting tapes performed well as SUAM with superconducting bulks. Therefore, we considered that it is necessary to evaluate the performance of SUAM using superconducting tapes, and it can improve the repulsive force by adding ribs.

 In this study, we used the application, JMAG-Designer 22.1, for the finite element method (FEM) to analyze basic electromagnetic field. We created two different models with 6 sheets in one layer, 72 mm long, 12 mm wide, 2 µm thick, and with the ribs, 65 mm long, 12 mm wide, 2 µm thick. Here, rib, shown in Fig.1(a) inset figure, is the tape structure placed perpendicularly to flat tapes to obtain larger repulsive force. We analyzed 1, 3, and 5 layers which is placed at 12 mm below the 4-pole magnet. Fig. 1(a) shows the calculation of repulsive force and Fig. 1(b) shows the restoring force for two models with 1, 3 and 5 layers of superconducting tapes with ribs and without ribs. Wafers can be levitated with a repulsive force of 5 – 10 N. Since there is no sudden movement, a restoring force of 0.2 N is enough to transport it. From the result, the SUAM can be used to transport wafers because it has sufficient repulsive force and restoring force to withstand lateral movement.

[1] Kinoshita Y, Zhang R, Otabe E S, Suzuki K, Tanaka Y, Nakashima H, Nakasaki T 2020 J. Phys.: Conf. Ser. 1590 012023

[2] Iwasaki S, Kinoshita Y, Ishii H, Otabe E S, Suzuki K, Nakasaki T 2022 J. Phys.: Conf. Ser. 2323 012025

Fig. 1 (a) Repulsive force and (b) Restoring force when the magnetized distance is 12 mm for with ribs and without ribs for 1, 3, and 5 tape layers.