Perpendicular magnetic random-access memory (MRAM) formation by direct self-assembly method

摘要

Some embodiments of the present disclosure relate to a method that achieves a substantially uniform pattern of magnetic random access memory (MRAM) cells with a minimum dimension below the lower resolution limit of some optical lithography techniques. A copolymer solution comprising first and second polymer species is spin-coated over a heterostructure which resides over a surface of a substrate. The heterostructure comprises first and second ferromagnetic layers which are separated by an insulating layer. The copolymer solution is subjected to self-assembly into a phase-separated material comprising a pattern of micro-domains of the second polymer species within a polymer matrix comprising the first polymer species. The first polymer species is then removed, leaving a pattern of micro-domains of the second polymer species. A pattern of magnetic memory cells within the heterostructure is formed by etching through the heterostructure while utilizing the pattern of micro-domains as a hardmask.

主权项

1. A method of forming a magnetic memory cell, comprising:
forming a heterostructure over a layer of dielectric material disposed over a substrate, wherein the heterostructure comprises first and second ferromagnetic layers which are separated by an insulating layer; forming a pattern of polymer pillars over the heterostructure, wherein a pillar comprises a cylindrical shape; etching through the heterostructure by utilizing the pattern of polymer pillars as a hardmask, thereby forming a pattern of magnetic memory cells within the heterostructure; depositing a sidewall material over the etched heterostructure; and etching the sidewall material to remove portions of the sidewall material horizontally-disposed on a surface of the first ferromagnetic layer or the second ferromagnetic layer, while leaving portions of the sidewall material vertically-disposed adjacent to sidewalls of the first ferromagnetic layer or the second ferromagnetic layer and the insulating layer substantially intact.