Methods for forming three dimensional NAND structures atop a substrate

Patent metadata

Field	Value
Publication number	US-8937021-B2
Application number	US-201414306535-A
Country	US
Kind code	B2
Filing date	Jun 17, 2014
Priority date	Jun 20, 2013
Publication date	Jan 20, 2015
Grant date	Jan 20, 2015

Abstract

In some embodiments, methods for forming a three dimensional NAND structure include providing to a process chamber a substrate having alternating nitride layers and oxide layers or alternating polycrystalline silicon consisting layers and oxide layers formed atop the substrate and a photoresist layer formed atop the alternating layers; etching the photoresist layer to expose at least a portion of the alternating layers; providing a process gas comprising sulfur hexafluoride and oxygen to the process chamber; providing RF power of about 4 kW to about 6 kW to a first inductive RF coil and a second inductive RF coil disposed proximate the process chamber to ignite the process gas to form a plasma, wherein a current flowing through the first inductive RF coil is out of phase with RF current flowing through the second inductive RF coil; and etching through a desired number of the alternating layers to form a feature.

First claim

The invention claimed is:

1. A method of forming a three dimensional NAND structure atop a substrate, comprising:
(a) providing to a process chamber a substrate having alternating nitride layers and oxide layers or alternating polycrystalline silicon consisting layers and oxide layers formed atop the substrate and a photoresist layer formed atop the alternating nitride layers and oxide layers or alternating polycrystalline silicon consisting layers and oxide layers;
(b) etching the photoresist layer to expose at least a portion of the alternating nitride layers and oxide layers or alternating polycrystalline silicon consisting layers and oxide layers;
(c) providing a process gas comprising sulfur hexafluoride (SF 6 ) and oxygen (O 2 ) to the process chamber;
(d) providing an RF power of about 4 kW to about 6 kW to a first inductive RF coil and a second inductive RF coil disposed proximate the process chamber to ignite the process gas to form a plasma, wherein a current flowing through the first inductive RF coil is out of phase with RF current flowing through the second inductive RF coil; and
(e) etching through a desired number of the alternating nitride layers and oxide layers or alternating polycrystalline silicon consisting layers and oxide layers to form a feature.

2. The method of claim 1 , further comprising:
(f) repeating (b)-(e) to form a plurality of adjacent features to at least partially form the NAND structure atop the substrate, wherein a depth of each feature decreases from a first side of the NAND structure to a second side of the NAND structure.

3. The method of claim 2 , wherein the plurality of adjacent features form a NAND staircase structure.

4. The method of claim 1 , wherein a bottom of the feature comprises an exposed portion of an oxide layer of the alternating nitride layers and oxide layers or alternating polycrystalline silicon consisting layers and oxide layers formed atop the substrate.

5. The method of claim 1 , wherein etching the photoresist layer comprises isotropically etching the photoresist to reduce a thickness and a width of the photoresist layer.

6. The method of claim 1 , wherein the process gas further comprises one of nitrogen (N 2 ) gas or helium (He) gas.

7. The method of claim 1 , wherein providing the process gas comprises providing sulfur hexafluoride (SF 6 ) at about 0.5 to about 20% of a total flow of the process gas provided to the process chamber.

8. The method of claim 1 , wherein a phase difference between the first inductive RF coil and the second inductive RF coil is about 180 degrees.

9. The method of claim 1 , wherein providing the process gas comprises providing oxygen (O 2 ) at about 60 to about 99.9% of a total flow of the process gas provided to the process chamber.

10. The method of claim 1 , wherein providing the RF power comprises providing an RF power at about 4.5 kW.

11. The method of claim 1 , wherein the first inductive RF coil and second inductive RF coil are concentrically disposed, wherein the first inductive RF coil is disposed about the second inductive RF coil.

12. The method of claim 1 , further comprising maintaining the process chamber at a pressure of between about 50 to about 90 mTorr while performing (e).

13. A computer readable medium, having instructions stored thereon that, when executed, cause a method of forming a three dimensional negated and or not-and (NAND) structure atop a substrate to be performed, the method comprising:
(a) providing to a process chamber a substrate having alternating nitride layers and oxide layers or alternating polycrystalline silicon consisting layers and oxide layers formed atop the substrate and a photoresist layer formed atop the alternating nitride layers and oxide layers or alternating polycrystalline silicon consisting layers and oxide layers;
(b) etching the photoresist layer to expose at least a portion of the alternating nitride layers and oxide layers or alternating polycrystalline silicon consisting layers and oxide layers;
(c) providing a process gas comprising sulfur hexafluoride (SF 6 ) and oxygen (O 2 ) to the process chamber;
(d) providing an RF power of about 4 kW to about 6 kW to a first inductive RF coil and a second inductive RF coil disposed proximate the process chamber to ignite the process gas to form a plasma, wherein a current flowing through the first inductive RF coil is out of phase with RF current flowing through the second inductive RF coil; and
(e) etching through a desired number of the alternating nitride layers and oxide layers or alternating polycrystalline silicon consisting layers and oxide layers to form a feature.

14. The computer readable medium of claim 13 , further comprising:
(f) repeating (b)-(e) to form a plurality of adjacent features to at least partially form the NAND structure atop the substrate, wherein a depth of each feature decreases from a first side of the NAND structure to a second side of the NAND structure.

15. The computer readable medium of claim 14 , wherein the plurality of adjacent features form a NAND staircase structure.

16. The computer readable medium of claim 13 , wherein a bottom of the feature comprises an exposed portion of an oxide layer of the alternating nitride layers and oxide layers or alternating polycrystalline silicon consisting layers and oxide layers formed atop the substrate.

17. The computer readable medium of claim 13 , wherein etching the photoresist layer comprises isotropically etching the photoresist to reduce a thickness and a width of the photoresist layer.

18. The computer readable medium of claim 13 , wherein a phase difference between the first inductive RF coil and the second inductive RF coil is about 180 degrees.

19. The computer readable medium of claim 13 , wherein providing the process gas comprises providing sulfur hexafluoride (SF 6 ) at about 0.5 to about 20% of a total flow of the process gas.

20. The computer readable medium of claim 13 , wherein providing the process gas comprises providing oxygen (O 2 ) at about 60 to about 99.9% of a total flow of the process gas provided to the process chamber.

Assignees

• Applied Materials Inc

Inventors

• Cho Han Soo
• Kim Sang Wook
• Han Joo Won
• Cho Kee Young
• Khan Anisul H

Classifications

• H10P50/283 Primary

  by chemical means · CPC title

• H01L21/31116 Primary

  Electricity · mapped topic