Methods for etching a structure for MRAM applications

Patent metadata

Field	Value
Publication number	US-11145808-B2
Application number	US-201916681351-A
Country	US
Kind code	B2
Filing date	Nov 12, 2019
Priority date	Nov 12, 2019
Publication date	Oct 12, 2021
Grant date	Oct 12, 2021

Abstract

Embodiments of the disclosure provide methods and apparatus for fabricating magnetic tunnel junction (MTJ) structures on a substrate for MRAM applications. In one embodiment, a method for forming a magnetic tunnel junction (MTJ) device structure includes performing a patterning process by an ion beam etching process in a processing chamber to pattern a film stack disposed on a substrate, wherein the film stack comprises a reference layer, a tunneling barrier layer and a free layer disposed on the tunneling barrier, and determining an end point for the patterning process.

First claim

What is claimed is:

1. A method for forming a magnetic tunnel junction (MTJ) device structure, comprising:
performing a first patterning process by an ion beam etching process in a processing chamber to pattern a film stack disposed on a substrate, wherein the film stack comprises a reference layer, a tunneling barrier layer and a free layer, wherein the film stack is disposed on a spin-orbit-torque SOT layer; and
determining an end point for the first patterning process before etching the free layer.

2. The method of claim 1 , further comprising:
forming a spacer layer covering sidewalls of the patterned film stack wherein the spacer layer stops prior to the SOT layer.

3. The method of claim 2 , wherein the spacer layer is a dielectric layer.

4. The method of claim 1 , wherein determining the end point further comprising:
receiving a signal from an ion beam generated during the ion beam etching process by an end point detector disposed in the processing chamber.

5. The method of claim 4 , wherein the end point detector is an optical emission spectroscopy and/or a secondary-ion mass spectrometry (SIMS).

6. The method of claim 4 , wherein the signal comprises an element released from the free layer.

7. The method of claim 2 , further comprising:
patterning the spacer layer;
performing an oxidation process on the substrate; and
forming a passivation layer covering the spacer layer.

8. The method of claim 7 , wherein the performing the oxidation process further comprises:
oxidizing the free layer exposed on the substrate.

9. The method of claim 2 , further comprising:
performing a second patterning process by the ion beam etching process in a processing chamber to pattern the free layer.

10. The method of claim 1 , wherein performing the patterning process further comprises:
determining the end point when the free layer is exposed.

11. The method of claim 9 , wherein determining the endpoint further comprises:
determining the endpoint when the SOT layer is exposed.

12. The method of claim 11 , wherein the determining the endpoint further comprising:
terminating the patterning process when a Mg element is traced when the SOT layer is fabricated from MgO.

13. The method of claim 1 , wherein the determining the endpoint further comprising:
terminating the patterning process when a Co, Fe, or B element is traced when the free layer is fabricated from CoFeB containing material.

14. The method of claim 7 , wherein the passivation layer is a dielectric layer.

15. A method for forming a magnetic tunnel junction (MTJ) device structure, comprising:
patterning a film stack disposed on a substrate by an ion beam etching process in a processing chamber, wherein the film stack comprises a reference layer, a tunneling barrier layer and a free layer disposed on the tunneling barrier; and
determining an end point by an end point detector of the processing chamber.

16. The method of claim 15 , wherein the end point is determined when the free layer is exposed.

17. The method of claim 15 , wherein the film stack further comprises a SOT layer disposed on the substrate under the free layer.

18. The method of claim 17 , wherein the end point is determined when the SOT layer is exposed.

19. A method for forming a magnetic tunnel junction (MTJ) device structure, comprising:
patterning a film stack disposed on a substrate by an ion beam etching process in a processing chamber, wherein the film stack comprises a reference layer, a tunneling barrier layer and a free layer disposed on the tunneling barrier;
determining an end point by an optical emission spectroscopy in the processing chamber; and
forming a passivation layer on the patterned film stack.

Assignees

• Applied Materials Inc

Inventors

• Kim Jong Mun
• Yu Minrui
• Park Chando
• Ling Mang-Mang
• Ahn Jaesoo
• Ying Chentsau Chris
• Nemani Srinivas D
• Pakala Mahendra
• Yieh Ellie Y

Classifications

• H10N50/85

  Materials of the active region · CPC title

• H01L43/10

  Electricity · mapped topic

• H01L27/222

  Electricity · mapped topic

• H01L43/12 Primary

  Electricity · mapped topic

• H01L43/02

  Electricity · mapped topic