Optimization on Dry-Etching Process for High-Density STT-MRAM

STT-MRAM (Spin-Transfer-Torque Magnetic Random-Access-Memory) with high-density is considered as one of the most promising storage candidates with potential applications. Considering the fabrication process of STT-MRAM, the patterning process has an obvious influence on the density and the quality of the storage cells. In the paper, optimization on the plasma etching process is conducted for the improvement of the pattern density. By the adjustment of the process and the introduction of the amorphous carbon as the sacrificial hard mask, the density of the patterned cells is improved, in which the bottom electrode spacing is optimized. In this way, the etching process is suitable for higher density STT-MRAM integration, while providing an practical approach for the high-density MTJ arrays. The simulation results demonstrate that the density of STT-MRAM can be improved by the proposed etching process. The optimization would be useful for future high-density STT-MRAM fabrication.