Method of forming a magnetic tunnel junction structure

• US 9,136,463 B2
• Filed: 11/20/2007
• Issued: 09/15/2015
• Est. Priority Date: 11/20/2007
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Li, Xia, Kang, Seung H., Zhu, Xiaochun
• Primary Examiner(s): Abdelaziez, Yasser A
• Application Number:
  US11/943,042
• Publication Number:
  US 20090130779A1
• Time in Patent Office: 2,856 Days
• Field of Search: 257/E21.232, 257/665, 257/587, 438/3, 438/551, 438/671, 438/77, 438/147, 438/736
• US Class Current: 1/1
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/80 Constructional details

Abstract

In a particular embodiment, a method is disclosed that includes forming a magnetic tunnel junction (MTJ) structure including a conductive layer on a substrate. The method also includes depositing a sacrificial layer on the conductive layer before depositing a patterning film layer.

Claims

1. A method comprising:

forming a magnetic tunnel junction (MTJ) structure including a conductive layer on a substrate;

depositing a sacrificial layer on the conductive layer, the sacrificial layer comprising silicon carbon;

depositing an amorphous carbon layer on the sacrificial layer, the sacrificial layer selected to have a chemical structure having substantially no impact on a resolution of a pattern definition with respect to the amorphous carbon layer;

depositing one or more hard mask and photo-resist layers on the amorphous carbon layer deposited on the sacrificial layer, the amorphous carbon layer located between the sacrificial layer and the one or more hard mask and photo-resist layers;

patterning and removing the one or more hard mask and photo-resist layers and the amorphous carbon layer; and

depositing a non-magnetic spacer film on an exposed portion of the sacrificial layer, wherein the sacrificial layer is comprised of the same material as the non-magnetic spacer film.

2. The method of claim 1, further comprising applying at least one pattern definition to the one or more hard mask and photo-resist layers and to the amorphous carbon layer.

3. The method of claim 2, further comprising removing the one or more hard mask and photo-resist layers and the amorphous carbon layer according to the at least one pattern definition.

4. The method of claim 2, further comprising patterning and removing the sacrificial layer.

5. The method of claim 4, further comprising depositing a second conductive layer on the conductive layer after the sacrificial layer is removed.

6. The method of claim 1, wherein the conductive layer comprises titanium (Ti), ruthenium (Ru), or a combination thereof.

7. The method of claim 1, wherein a thickness of the sacrificial layer is selected to have a photo resolution having a range of approximately 10 angstroms to approximately 5000 angstroms.

8. The method of claim 1, further comprising annealing the MTJ structure to define a magnetic orientation of a fixed layer of the MTJ structure to form a MTJ device.

9. A method comprising:

depositing a first electrode on a substrate;

forming a magnetic tunnel junction (MTJ) structure on the first electrode, the MTJ structure including a tunnel barrier layer between two magnetic layers;

depositing a second electrode on the MTJ structure;

depositing a sacrificial cap layer on the second electrode before deposition of an amorphous carbon layer, the sacrificial cap layer to reduce oxidation and erosion of the second electrode during at least one patterning process, the sacrificial cap layer comprising silicon carbon;

depositing the amorphous carbon layer on the sacrificial cap layer, the sacrificial cap layer selected to have a chemical structure having substantially no impact on a resolution of a pattern definition with respect to the amorphous carbon layer;

depositing a hard mask layer and a photo-resist layer on the amorphous carbon layer, the amorphous carbon layer located between the sacrificial cap layer and the hard mask layer;

patterning and removing the hard mask layer, the photo-resist layer, and the amorphous carbon layer; and

depositing a non-magnetic spacer layer over an exposed portion of the sacrificial cap layer, wherein the sacrificial cap layer is comprised of the same material as the non-magnetic spacer layer.

10. The method of claim 9, further comprising performing a magnetic anneal process on the MTJ structure to orient a magnetic field associated with at least one of the two magnetic layers.

11. The method of claim 10, wherein the photo-resist layer comprises an anti-reflective layer.

12. The method of claim 9, further comprising:

performing a pattern definition process to define at least one pattern onto the photo-resist layer prior to removing the photo-resist layer, the hard mask layer, and the amorphous carbon layer;

selectively removing portions of the photo-resist layer, the hard mask layer, the amorphous carbon layer, the sacrificial cap layer, and the second electrode according to the at least one pattern to expose the portion of the sacrificial layer; and

removing the photo-resist layer, the hard mask layer, and the amorphous carbon layer.

13. The method of claim 12, further comprising:

after depositing the non-magnetic spacer layer, depositing an inter-layer dielectric layer over the non-magnetic spacer layer;

selectively removing a portion of the inter-layer dielectric layer to a level that exposes a portion of the non-magnetic spacer layer; and

performing a Chemical-Mechanical Planarization (CMP) process to selectively remove portions of the inter-layer dielectric layer, the non-magnetic spacer layer, and the sacrificial cap layer to expose the second electrode at a substantially planar surface.

14. The method of claim 13, further comprising depositing a conductive layer onto the substantially planar surface of the second electrode, wherein the conductive layer is coupled to the second electrode.

20. The method of claim 9, wherein a thickness of the sacrificial cap layer is selected to have a photo resolution of approximately 10 angstroms.

21. The method of claim 9, wherein the sacrificial cap layer is configured to reduce corner rounding of the second electrode during at least one patterning process and to reduce exposure of a sidewall of the MTJ structure during the at least one patterning process.

15. A method comprising:

forming a magnetic tunnel junction (MTJ) structure including a tunnel barrier layer between two magnetic layers;

depositing a top electrode on the MTJ structure;

depositing a sacrificial cap layer onto the top electrode before depositing an amorphous carbon layer onto the top electrode, the sacrificial cap layer comprising silicon carbon;

depositing the amorphous carbon layer on the sacrificial cap layer, wherein the sacrificial cap layer is selected to have a chemical structure having substantially no impact on a resolution of a pattern definition with respect to the amorphous carbon layer;

depositing a hard mask layer and a photo-resist layer on the amorphous carbon layer, wherein the amorphous carbon layer is located between the sacrificial cap layer and the hard mask layer;

patterning and removing the hard mask layer, the photo-resist layer, and the amorphous carbon layer; and

depositing a non-magnetic spacer layer over an exposed portion of the sacrificial cap layer, wherein the sacrificial cap layer is comprised of the same material as the non-magnetic spacer layer.

16. The method of claim 15, further comprising:

performing a first photo patterning process to define a pattern in the hard mask layer and the photo-resist layer to pattern the hard mask layer and the photo-resist layer;

selectively removing a portion of the hard mask layer and of the photo-resist layer according to the defined pattern;

removing the photo-resist layer; and

performing a second etching process to transfer a second pattern to the amorphous carbon layer, the sacrificial cap layer, and the top electrode.

17. The method of claim 16, further comprising:

removing the hard mask layer and the amorphous carbon layer; and

defining the second pattern on the MTJ structure using the sacrificial cap layer and the top electrode as a hard mask.

18. The method of claim 17, further comprising selectively removing a portion of the MTJ structure according to the second pattern.

19. The method of claim 18, further comprising:

after depositing the non-magnetic spacer layer, depositing an inter-layer dielectric layer over the non-magnetic spacer layer;

selectively removing a portion of the inter-layer dielectric layer to expose a portion of the non-magnetic spacer layer that is proximate to the sacrificial cap layer;

performing a Chemical Mechanical Planarization (CMP) process to remove a portion of the inter-layer dielectric layer, the non-magnetic spacer layer, and the sacrificial cap layer to define a substantially planar surface and to expose the top electrode at the substantially planar surface; and

depositing a conductive layer over the top electrode.