Magnetic Memory Cell Electrode Structure for Etching Stop Control

The patent applies a multi-layer electrode structure where the third electrode is formed before the magnetoresistance effect element and selector layers. This preliminary electrode serves as a protective layer and etching stopper during subsequent ion beam etching processes, preventing damage to underlying selector material layers while enabling precise etching of upper layers.

The patent introduces intermediate electrode layers (second and third electrodes) between the substrate and the magnetoresistance effect elements. These intermediary layers act as protective barriers during etching processes, allowing precise etching of the magnetoresistance effect elements while preventing ion beam damage to the selector material layers below.

The patent divides the electrode structure into multiple segmented layers (third electrode, second electrode, first electrode, and fourth electrode) with distinct functions. Each layer serves specific purposes: the third electrode as etching stopper, the second electrode as intermediate layer, the first electrode as bottom electrode, and the fourth electrode as top electrode. This segmentation enables precise control over etching processes and reliable cell separation.

The patent assigns different materials and properties to different electrode layers based on their specific functional requirements. The third electrode uses materials with appropriate etching resistance properties to serve as etching stopper, while other layers are optimized for their respective functions. This local quality differentiation enables precise etching control without compromising overall device performance.