Method of forming a pattern using ion beams of bilateral symmetry, a method of forming a magnetic memory device using the same, and an ion beam apparatus generating ion beams of bilateral symmetry

Patent metadata

Field	Value
Publication number	US-9627610-B2
Application number	US-201514919723-A
Country	US
Kind code	B2
Filing date	Oct 21, 2015
Priority date	Nov 25, 2014
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

A pattern-forming method includes providing a first ion beam at a first incidence angle and a second ion beam at a second incidence angle to a surface of an etch target layer formed on a substrate. Patterns are formed by patterning the etch target layer using the first and second ion beams. The first ion beam and the second ion beam are substantially symmetrical to each other with respect to a normal line that is perpendicular to a top surface of the substrate. Each of the first and second incidence angles is greater than 0 degrees and smaller than an angle obtained by subtracting a predetermined angle from 90 degrees.

First claim

What is claimed is:

1. A method of forming a pattern in an etch target layer formed on a substrate, the method comprising:
radiating a first ion beam to a surface of the etch target layer at a first incidence angle and a second ion beam to the surface of the etch target layer at a second incidence angle; and
forming patterns by patterning the etch target layer using the first and second ion beams,
wherein the first ion beam and the second ion beam are substantially symmetrical to each other with respect to a normal line that is substantially perpendicular to a top surface of the substrate,
wherein each of the first and second incidence angles is greater than 0 degrees, measured with respect to the normal line, and smaller than an angle obtained by subtracting a magnitude of a first angle (α) from 90 degrees, and
wherein the magnitude of the first angle (α) is defined by the equation
α=arctan (B/A), where “A” denotes a distance between adjacent patterns, and “B” denotes a height of the patterns.

2. The method of claim 1 , wherein forming the patterns comprises: etching the etch target layer using the first and second ion beams to form a trench in the etch target layer, and
wherein each of the first and second incidence angles is greater than a second angle at which an etch rate at a bottom surface of the trench is twice an etch rate at a sidewall of the trench.

3. The method of claim 1 , wherein the etch target layer includes at least one magnetic layer.

4. The method of claim 1 , wherein the first ion beam and the second ion beam are radiated to one region of the surface of the etch target layer at substantially the same time, and
wherein the one region is a region of a range corresponding to the distance between the patterns.

5. The method of claim 4 , wherein each of the patterns has a first sidewall and a second sidewall arranged opposite to each other,
wherein the first sidewall of one pattern in a pair of adjacent patterns faces the second sidewall of the other pattern in the pair of adjacent patterns,
wherein the etch target layer is etched by the first ion beam to form the first sidewall, and
wherein the etch target layer is etched by the second ion beam to form the second sidewall.

6. The method of claim 4 , wherein a magnitude of the first incidence angle is substantially equal to a magnitude of the second incidence angle.

7. A method of forming a magnetic memory device, the method comprising:
providing a first ion beam at a first incidence angle and a second ion beam at a second incidence angle to a surface of a magnetic tunnel junction layer formed on a substrate; and
forming magnetic tunnel junction patterns by patterning the magnetic tunnel junction layer using the first ion beam and the second ion beam,
wherein the first ion beam and the second ion beam are substantially symmetrically arranged with respect to a normal line that is perpendicular to a top surface of the substrate,
wherein each of the first and second incidence angles measured with respect to the normal line is greater than 0 degrees and smaller than an angle obtained by subtracting a magnitude of a first angle (α) from 90 degrees, and
wherein the magnitude of the first angle (α) is defined by the equation α=arctan (B/A)
where “α” denotes the first angle, “A” denotes a distance between adjacent magnetic tunnel junction patterns, and “B” denotes a height of the magnetic tunnel junction patterns.

8. The method of claim 7 , wherein forming the magnetic tunnel junction patterns comprises: etching the magnetic tunnel junction layer using the first and second ion beams to form a trench in the magnetic tunnel junction layer, and
wherein each of the first and second incidence angles is greater than a second angle at which an etch rate at a bottom surface of the trench is twice an etch rate at a sidewall of the trench during etching.

9. The method of claim 7 , wherein the magnetic tunnel junction layer comprises: a first magnetic layer; a tunnel barrier layer; and a second magnetic layer sequentially stacked on the substrate, and
wherein forming the magnetic tunnel junction patterns comprises: sequentially etching the second magnetic layer, the tunnel barrier layer, and the first magnetic layer using the first ion beam and the second ion beam.

10. The method of claim 9 , wherein each of the first and second magnetic layers has a magnetization direction that is substantially perpendicular to an interface between the second magnetic layer and the tunnel barrier layer.

11. The method of claim 9 , wherein each of the first and second magnetic layers has a magnetization direction that is substantially parallel to an interface between the second magnetic layer and the tunnel barrier layer.

12. The method of claim 7 , wherein the first ion beam and the second ion beam are provided to one region of the surface of the magnetic tunnel junction layer at substantially the same time, and
wherein the one region is a region of a range corresponding to the distance between adjacent magnetic tunnel junction patterns.

13. The method of claim 12 , wherein each of the magnetic tunnel junction patterns has a first sidewall and a second sidewall arranged opposite to each other,
wherein the first sidewall of a magnetic tunnel junction pattern in an adjacent pair faces the second sidewall of the other magnetic tunnel junction pattern in the adjacent pair,
wherein the magnetic tunnel junction layer is etched by the first ion beam to form the first sidewall, and
wherein the magnetic tunnel junction layer is etched by the second ion beam to form the second sidewall.

14. The method of claim 12 , wherein the first incidence angle is substantially equal to the second incidence angle.

15. A method of forming a magnetic memory device, the method comprising:
generating plasma over a surface of a magnetic tunnel junction layer formed on a substrate, wherein a sheath region is defined between the plasma and the surface of the magnetic tunnel junction layer, and wherein a number of electrons of the sheath region is less than a number of electrons of the plasma;
providing insulators between the plasma and the surface of the magnetic tunnel junction layer to change a shape of a boundary between the plasma and the sheath region;
radiating a first ion beam to the surface of the magnetic tunnel junction layer at a first incidence angle and a second ion beam to the surface of the magnetic tunnel junction at a second incidence angle, wherein the first ion beam and the second ion beam each intersect the boundary between the plasma and the sheath region so as to be radiated to the surface of the magnetic tunnel junction layer through gap regions between the insulators; and
forming magnetic tunnel junction patterns by patterning the magnetic tunnel junction layer using the first ion beam and the second ion beam,
wherein the first ion beam and the second ion beam are provided substantially symmetrically to each other with respect to a normal line that is perpendicular to a top surface of the substrate,
wherein each of the first and second incidence angles, measured with respect to the normal line, is greater than 0 degrees and smaller than an angle obtained by subtracting a first angle (α) from 90 degrees, with respect to the normal, and
wherein the first angle (α) is defined by the equation

α=arctan (B/A), where “A” denotes a distance between adjacent magnetic tunnel junction patterns, and “B” denotes a height of the magnetic tunnel junction patterns.

16. The method of claim 15 , wherein forming the magnetic tunnel junction pat

Assignees

• Park Jongchul
• Kwon Hyungjoon
• Samsung Electronics Co Ltd

Inventors

• Park Jongchul
• Kwon Hyungjoon

Classifications

• H10P50/242 Primary

  of Group IV materials · CPC title

• H01J37/32623

  Mechanical discharge control means · CPC title

• H01L43/12 Primary

  Electricity · mapped topic

• H01J37/32422

  Arrangement for selecting ions or species in the plasma · CPC title

• H01J37/32357 Primary

  Generation remote from the workpiece, e.g. down-stream · CPC title