Diamond-like carbon hardmask for MRAM

Patent metadata

Field	Value
Publication number	US-10840441-B2
Application number	US-201816131989-A
Country	US
Kind code	B2
Filing date	Sep 14, 2018
Priority date	Sep 14, 2018
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

Techniques for MRAM patterning using a diamond-like carbon hardmask are provided. In one aspect, a method of forming an MRAM device includes: forming an MRAM stack on a substrate; depositing a metal hardmask layer on the MRAM stack; depositing a diamond-like carbon layer on the metal hardmask layer; forming a patterned resist on the diamond-like carbon layer; patterning the diamond-like carbon layer using the patterned resist to form a diamond-like carbon pillar; patterning the metal hardmask layer using the diamond-like carbon pillar to form a patterned metal hardmask; and patterning the MRAM stack into an MRAM pillar using the patterned metal hardmask to form the MRAM device. An MRAM device is also provided.

First claim

What is claimed is:

1. A method of forming a magnetoresistive random access memory (MRAM) device, the method comprising the steps of:
forming an MRAM stack on a substrate, wherein the MRAM stack directly contacts at least a portion of the substrate;
depositing a metal hardmask layer directly on the MRAM stack;
depositing a diamond-like carbon layer directly on the metal hardmask layer;
incorporating at least one metal during deposition of the diamond-like carbon layer such that the diamond-like carbon layer is electrically conductive;
forming a patterned resist on the diamond-like carbon layer;
patterning the diamond-like carbon layer using the patterned resist to form a diamond-like carbon pillar;
patterning the metal hardmask layer using the diamond-like carbon pillar to form a patterned metal hardmask; and
patterning the MRAM stack into an MRAM pillar using the patterned metal hardmask to form the MRAM device.

2. The method of claim 1 , further comprising the step of:
fully removing the diamond-like carbon pillar after patterning the MRAM stack.

3. The method of claim 1 , wherein the substrate contains a metal landing pad, the method further comprising the step of:
forming the MRAM stack on the substrate over the metal landing pad.

4. The method of claim 1 , wherein the MRAM stack comprises a magnetic tunnel junction (MTJ) element.

5. The method of claim 4 , wherein the MTJ element comprises:
a first magnetic metal layer;
a tunnel barrier disposed on the first magnetic metal layer; and
a second magnetic metal layer disposed on the tunnel barrier.

6. The method of claim 1 , wherein the metal hardmask layer comprises tantalum nitride, titanium nitride, tungsten, and combinations thereof.

7. The method of claim 1 , wherein the diamond-like carbon material comprises amorphous carbon.

8. The method of claim 7 , wherein the diamond-like carbon material comprises from about 10 atomic percent hydrogen to about 50 atomic percent hydrogen and ranges therebetween.

9. The method of claim 7 , wherein the diamond-like carbon material comprises less than about 1 atomic percent hydrogen.

10. The method of claim 1 , wherein the diamond-like carbon material is deposited to a thickness of from about 100 Å to about 300 Å and ranges therebetween.

11. The method of claim 1 , wherein the at least one metal is selected from the group consisting of: copper, titanium, and combinations thereof.

Assignees

• IBM

Inventors

• Annunziata Anthony
• Marchack Nathan P
• O'Sullivan Eugene
• Kothandaraman Chandrasekharan

Classifications

• H10P76/4085

  characterised by the processes involved to create the masks · CPC title

• H10P76/4083

  characterised by their behaviours during the lithography processes, e.g. soluble masks or redeposited masks · CPC title

• H10P76/405

  characterised by their composition, e.g. multilayer masks · CPC title

• H10P14/6902

  composed of carbon, e.g. alpha-C, diamond or hydrogen doped carbon · CPC title

• H01L43/02

  Electricity · mapped topic