Abstract: Surface planarization for storage cells of magnetic random access memory (MRAM) is investigated by atomic force microscope (AFM) and scan electron microscope (SEM).AFM images indicate that the surface of Al films deposited by magnetron consists of many particles with size of tens of nanometers.The roughness of surface depicted with root mean square (RMS) is more than 10nm.The roughness of surface is improved after the film of refractory metal Ti or Ta deposited on Al film.Under the conditions of small pressure and low rotate speed,the roughness of surface (the value of RMS) reaches less than 1nm by applying chemical mechanical planarization (CMP).SEM images show that the surface of the whole chip can be planarized greatly by coating photoresist on surface.The photoresist is removed by reactive ion etch under the same etch rate to photoresist and oxide.

Key words: MRAM,  planarization, roughness, RMS