Speaker
Description
A concept for a magnetic annealing oven for applications in the fabrication of MRAM and other GMR, TMR effect devices is investigated. With the oven, it is possible to anneal 20 to 50 wafers with a diameter of 200-300 mm at temperatures up to 450°C in a magnetic field of 1 T or more. The magnetic field in this study is created by HTS coils made up of THEVA, SuperOx, Sumitomo and Shanghai Superconducting tapes in Helmholtz and Maxwell coil configurations that allow high magnetic fields at the wafer position with a high uniformity of the field in direction and magnitude. This study includes the literature research about magnetic annealing requirements for MRAMs and other GMR effect devices, known concepts for generating high and uniform magnetic fields in a large volume, and technologies to build high-temperature superconducting coils for this purpose. Later, a setup of a FEM-model to simulate the magnetic field in mentioned coil arrangements for the given purpose is proposed and then a parameter variation is carried out to optimize the coil arrangement to achieve the best field uniformity for magnetic fields of 1 T at the wafers while minimizing the total cost for the coil. Major targets are to maintain minimal wire consumption and the operation at the highest possible temperature
