Structure and Method to Form Phase Change Memory Cell with Self-Align Top Electrode Contact

• US 20200136043A1
• Filed: 10/26/2018
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: OK, Injo, Na, Myung-Hee, Saulnier, Nicole, Pranatharthiharan, Balasubramanian
• Granted Patent: US 10,833,267 B2
• Time in Patent Office: Days
• CPC Class Codes: H10B 63/30 comprising selection components having three or more electrodes, e.g. transistors
• CPC Class Codes: H10B 63/80 Arrangements comprising multiple bistable or multi-stable switching components of the same type on a plane parallel to the substrate, e.g. cross-point arrays
• CPC Class Codes: H10N 70/063 by etching of pre-deposited switching material layers, e.g. lithography
• CPC Class Codes: H10N 70/231 based on solid-state phase change, e.g. between amorphous and crystalline phases, Ovshinsky effect
• CPC Class Codes: H10N 70/841 Electrodes
• CPC Class Codes: H10N 70/883 Oxides or nitrides

Abstract

A self-align metal contact for a phase control memory (PCM) element is provided that mitigates unwanted residual tantalum nitride (TaN) particles that would otherwise remain after patterning a TaN surface using an RIE process.

Claims

1. A method of forming a self-align contact for a phase change memory element, comprising steps of:

forming a bottom element on a landing pad of a phase change memory element;

forming a via that extends through a first layer of material that overlays the bottom element and extends through a second layer of material that overlays the first layer;

depositing a third layer of material over the second layer of material and within the via;

performing a chemical mechanical polish operation to remove the third layer of material that overlays the second layer of material;

forming a recess in the third layer of material within the via;

depositing a top electrode metal material over the second layer of material and within the recess;

performing a second chemical mechanical polish operation to remove the top electrode metal that overlays the second layer of material;

depositing a capping material over the second layer of material and the top electrode metal within the recess;

depositing another layer of the second layer of material over the capping material;

patterning the capping material and the another layer to form a metal via that extends to the top electrode metal within the recess;

depositing a conductive material over the another layer and the metal via; and

performing a third chemical mechanical polish operation to remove the conductive material that overlays the another layer in order to form the self-align contact.

2. The method of claim 1, wherein reactive ion etching is used when patterning the capping material and the another layer.

3. The method of claim 1, wherein the bottom element is formed from a TaN material or a TiN material.

4. The method of claim 2, wherein the bottom element further comprises NBLOK to form a bi-layer in the bottom element.

5. The method of claim 1, wherein the first layer of material is formed from NBLOK, and the second layer of material is formed from tetraethoxysilane (TEOS).

6. The method of claim 1, wherein the third layer of material is formed from GeSbTe.

7. The method of claim 1, wherein the capping material is formed from NBLOK.

8. The method of claim 1, wherein the conductive material is formed from one of copper (Cu) or tungsten (W).

9. A method of forming a self-align contact for a phase change memory element, comprising steps of:

forming a phase change memory element in a substrate; and

forming a self-align metal contact for the phase change memory element using a reactive ion etching process.

10. The method of claim 9, further comprising:

patterning a layer of material using the reactive ion etching process to form a recess within a via extending above the phase change memory element.

11. The method of claim 10, further comprising:

filling the via with a second material using a chemical metal polish process.

12. The method of claim 11, wherein the self-align metal contact is formed above the second material in the via.

13. The method of claim 11, wherein the material is GeSbTe and the second material is tantalum nitride (TaN).

14. A memory array comprising a plurality of phase change memory elements, wherein at least one of the phase change memory elements comprises:

a bottom element coupled to a landing pad of the phase change memory element;

a GeSbTe portion coupled to the bottom element;

a top electrode metal coupled to the GeSbTe portion; and

a self-aligned metal contact coupled to the top electrode metal.

15. The phase change memory element of claim 14, wherein the bottom element is formed from a TaN material or a TiN material.

16. The phase change memory element of claim 15, wherein the bottom element further comprises an NBLOK material to form a bi-layer in the bottom element.

17. The phase change memory element of claim 14, wherein the top electrode metal is formed from a TaN material or a TiN material.

18. The phase change memory element of claim 14, wherein the self-aligned metal contact is formed from one of copper (Cu) or tungsten (W).

19. The memory array of claim 14, wherein the GeSbTe portion is formed in a via extending above the bottom element.

20. The memory element of claim 19, wherein the via is coated with a metal liner.