Manufacturing method for annular magnetic random access memory unit structure

Abstract

The invention provides a manufacturing method for an annular magnetic random access memory (MRAM) unit structure. The manufacturing method comprises the steps of supplying a substrate, successively depositing a lower electrode layer, an MTJ film, an upper electrode layer and a hard mask layer on the substrate; spin-coating a photoresist layer which is sensitive to light strength and is specialized for double developing technology on the hard mask layer; supplying a mask plate which is specially designed for an annular MTJ, and exposing the photoresist layer; performing primary developing on the photoresist layer by a positive aqueous developer, leaving a cylindrical photoresist layer below a portion which is shielded by the mask plate; developing the remained photoresist layer by a negative organic liquid developer, eliminating the part which is next to the center in the cylindrical photoresist layer, leaving the portion which is next to outside, thereby forming a cylindrical photoresist layer; using the photoresist layer as the mask, etching the hard mask layer below the photoresist layer; and using the hard mask layer as the mask, successively etching the upper electrode layer and the MTJ film below the hard mask layer, thereby forming the annular MTJ. According to the manufacturing method, the specially designed mask plate is used and the double developing technology is adopted for realizing manufacture of a small-size annular MRAM unit structure.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular, the invention relates to a manufacturing method of a small-sized annular magnetic random access memory unit structure. Background technique [0002] Magnetic Random Access Memory (MRAM) is considered the most promising candidate for the next generation of Non-Volatile Memory (NVM) due to its high speed, low power consumption, and data retention . But ordinary MRAM has the following defects: [0003] (1) For current commercial MRAM products, the cell size of MRAM is very large and the memory density is relatively low; [0004] (2) Due to the magnetic switching direction, elliptical (solid) products are usually used, while circular (solid) products cannot be applied to in-plane spin-transfer torque magnetic random access memory (in-plane Spin-Transfer Torque MRAM). [0005] Compared with the magnetic tunnel junction (MTJ) of the solid structure (solid block), ...

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Problems solved by technology

[0003] (1) For current commercial MRAM products, the cell size of MRAM is very large and the memory density is relatively low;

[0004] (2) Due to the magnetic switching direction, elliptical (solid) products are usually used, while circular (solid) products cannot be applied to in-plane spin-transfer torque magnetic random access memory (in-plane Spin-Transfer Torque MRAM) in

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