Differential etch rate control of layers deposited by chemical vapor deposition

• US 7,988,875 B2
• Filed: 02/07/2008
• Issued: 08/02/2011
• Est. Priority Date: 02/08/2007
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Furuta, Gaku, Choi, Soo Young
• Primary Examiner(s): Vinh; Lan
• Assistant Examiner(s): Angadi; Maki A
• Application Number:
  US12/027,964
• Publication Number:
  US 20080190886A1
• Time in Patent Office: 1,272 Days
• Field of Search: 216/80, 216/2, 216/39, 216/46, 216/67, 438/791, 438/792, 118/724
• US Class Current: 216/80
• CPC Class Codes: C03C 17/34 with at least two coatings having different compositions C03C17/44 takes precedence
• CPC Class Codes: C03C 2218/33 by etching
• CPC Class Codes: C23C 16/308 Oxynitrides
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/31116 by dry-etching

Abstract

A method and apparatus is provided for controlling the etch profile of a multilayer layer stack by depositing a first and second material layer with differential etch rates in the same or different processing chamber. In one embodiment of the invention, a process for etching substrate material is provided including depositing a first silicon-containing material layer having a first etch rate on the substrate surface from a nitrogen-containing precursor at a first flow rate and a silicon-containing precursor, depositing a second silicon-containing material layer having a second etch rate different than the first etch rate on the first silicon-containing material layer from the nitrogen-containing precursor at a second flow rate different than the first flow rate and the silicon-containing precursor, etching the first silicon-containing material layer and the second silicon-containing material layer, and forming a taper etch profile in the first silicon-containing material layer and the second silicon-containing material layer.

Claims

1. A method for processing a substrate, comprising:

depositing a first silicon-containing material layer having a first etch rate on the substrate surface from a silicon-containing precursor and a nitrogen-containing precursor, the nitrogen-containing precursor introduced into a processing chamber at a first flow rate;

depositing a second silicon-containing material layer having a second etch rate different than the first etch rate on the first silicon-containing material layer from the silicon-containing precursor and the nitrogen-containing precursor, the nitrogen-containing precursor having a second flow rate different than the first flow rate;

etching the first silicon-containing material layer and the second silicon-containing material layer; and

forming a taper etch profile in the first silicon-containing material layer and the second silicon-containing material layer.

2. The method of claim 1, wherein the first flow rate is greater than the second flow rate, the first etch rate is greater than the second etch rate, and the taper etch profile tapers from the substrate surface towards the second silicon-containing material layer.

3. The method of claim 2, wherein the taper etch profile forms an angle less than 90 degrees with the substrate surface from the etched sidewalls of the first silicon-containing material layer to the etched sidewalls of the second silicon-containing material layer.

4. The method of claim 1, wherein the first flow rate is less than the second flow rate, the first etch rate is less than the second etch rate and the taper etch profile tapers from the second silicon-containing material layer towards the substrate surface.

5. The method of claim 4, wherein the taper etch profile forms an angle less than 90 degrees with the substrate surface from the etched sidewalls of the second silicon-containing material layer to the etched sidewalls of the first silicon-containing material layer.

6. The method of claim 1, wherein the first silicon-containing material layer and the second silicon-containing material layer comprise silicon oxide.

7. The method of claim 6, wherein the first etch rate is a wet etch rate between about 2000 Å

/min and about 3000 Å

/min and the second etch rate is a wet etch rate less than about 2000 Å

/min.

8. The method of claim 7, wherein the nitrogen-containing precursor comprises nitrous oxide (N₂O).

9. The method of claim 1, wherein the first silicon-containing material layer and the second silicon-containing material layer comprise silicon nitride.

10. The method of claim 9, wherein etching of the dual material layer is performed by wet etch and wherein the first etch rate is a wet etch rate between about 300 Å

/min and about 500 Å

/min and the second etch rate is a wet etch rate less than about 300 Å

/min.

11. The method of claim 9, wherein the nitrogen-containing precursor comprises ammonia gas (NH₃).

12. The method of claim 1, wherein the nitrogen-containing precursor comprises a mixture of nitrogen (N₂) gas and hydrogen (H₂) gas with the second flow rate of the nitrogen gas less than the first flow rate of the nitrogen gas and wherein the hydrogen gas increases and has a first flow rate of zero and a second flow rate of hydrogen gas greater than the first flow rate of hydrogen gas.

13. The method of claim 1, wherein the first silicon-containing material layer comprises silicon oxide and the second silicon-containing material layer comprises silicon nitride.

14. The method of claim 13, wherein the selectivity of the first etch rate versus the second etch rate is about 10:

1 to about 20;

1.

15. The method of claim 1, wherein the depositing a first silicon-containing material layer and depositing a second silicon-containing material layer are performed in a continuous manner in the same processing chamber.

16. The method of claim 15, wherein the second flow rate of the nitrogen-containing precursor increases or decreases continuously from the first flow rate.

17. The method of claim 1, wherein the dual material layer is deposited on a substrate for fabricating a device selected from the group consisting of surface-conduction electron-emitter display (SED), liquid crystal display (LCD), plasma display panels (PDP), field emission display (FED), and organic light emitting diode (OLED).

18. A method for processing a substrate, comprising:

depositing a first silicon-containing material layer having a first etch rate on the substrate surface from a silicon-containing precursor and a nitrogen-containing precursor, the nitrogen-containing precursor introduced into a processing chamber at a first flow rate;

adjusting the flow rate of the of the nitrogen-containing precursor to a second flow rate different than the first flow rate;

depositing in situ a second silicon-containing material layer having a second etch rate different than the first etch rate;

etching the first silicon-containing material layer and the second silicon-containing material layer; and

forming an etch profile in the first silicon-containing material layer and the second silicon-containing material layer, the etch profile forming an etch angle less than 90°

with the substrate surface from the etched sidewalls of the first silicon-containing material layer to the etched sidewalls of the second silicon-containing material layer.

19. The method of claim 18, wherein the first silicon-containing material layer and the second silicon-containing material layer comprise silicon oxide, silicon nitride, or combinations thereof.

20. The method of claim 18, wherein the nitrogen-containing precursor comprises a gas selected from the group consisting of nitrous oxide (N₂O), ammonium gas (NH₃), nitrogen gas (N₂), and combinations thereof.

21. The method of claim 20, wherein the processing gas further comprises hydrogen gas.

22. The method of claim 18, wherein the dual material layer is deposited on a substrate for fabricating a device selected from the group consisting of surface-conduction electron-emitter display (SED), liquid crystal display (LCD), plasma display panels (PDP), field emission display (FED), and organic light emitting diode (OLED).

23. A method for processing a substrate, comprising:

depositing a first silicon-containing material layer having a first etch rate on the substrate surface from a first nitrogen-containing precursor and a silicon-containing precursor;

depositing a second silicon-containing material layer having a second etch rate different than the first etch rate on the first silicon-containing material layer from a second nitrogen-containing precursor and the silicon-containing precursor;

etching the first silicon-containing material layer and the second silicon-containing material layer; and

forming an etch profile in the first silicon-containing material layer and the second silicon-containing material layer, the etch profile forming an etch angle less than 90°

with the substrate surface from the etched sidewalls of the first silicon-containing material layer to the etched sidewalls of the second silicon-containing material layer.

24. The method of claim 23, wherein one of either the first nitrogen-containing precursor or the second nitrogen-containing precursor comprises nitrogen oxide (N₂O) and the remaining first nitrogen-containing precursor or second nitrogen-containing precursor comprises a gas selected from the group consisting of ammonium gas (NH₃), nitrogen gas (N₂), and combinations thereof.

25. The method of claim 23, wherein the depositing a first silicon-containing material layer and depositing a second silicon-containing material layer are performed in a continuous manner in the same processing chamber.