Selective growth of silicon nitride

• US 9,911,595 B1
• Filed: 03/17/2017
• Issued: 03/06/2018
• Est. Priority Date: 03/17/2017
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Smith, David Charles, Hausmann, Dennis M.
• Primary Examiner(s): McCall Shepard, Sonya D
• Application Number:
  US15/462,695
• Time in Patent Office: 354 Days
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02219 the compound comprising silicon and nitrogen
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/31138 by dry-etching
• CPC Class Codes: H01L 21/32 using masks
• CPC Class Codes: H01L 21/321 After treatment

Abstract

Methods and apparatuses for selectively depositing silicon nitride on silicon surfaces relative to silicon oxide surfaces and selectively depositing silicon nitride on silicon oxide surfaces relative to silicon surfaces are provided herein. Methods involve exposing the substrate to an alkene which is selectively reactive with the silicon surface to block the silicon surface by forming an organic moiety on the silicon surface prior to depositing silicon nitride selectively on silicon oxide surfaces using thermal atomic layer deposition. Methods involve exposing the substrate to an alkylsilylhalide which is selectively reactive with the silicon oxide surface to block the silicon oxide surface by forming an organic moiety on the silicon oxide surface prior to depositing silicon nitride selectively on silicon surfaces using thermal atomic layer deposition.

Claims

1. A method of depositing silicon nitride on a semiconductor substrate, the method comprising:

providing the semiconductor substrate having an exposed silicon oxide surface and an exposed silicon surface;

exposing the semiconductor substrate to a blocking reagent to block one of the exposed silicon oxide surface and the exposed silicon surface by forming an organic moiety on the one of the exposed silicon oxide surface and the exposed silicon surface while the other of the exposed silicon oxide surface and the exposed silicon surface remains unblocked; and

selectively depositing silicon nitride on the other of the exposed silicon oxide surface and the exposed silicon surface by one or more thermal atomic layer deposition cycles, each cycle comprising;

exposing the semiconductor substrate having the blocked and unblocked surfaces to a silicon-containing precursor to adsorb the silicon-containing precursor to the unblocked surface; and

exposing the semiconductor substrate to a nitrogen-containing reactant without igniting a plasma to form silicon nitride selectively on the unblocked surface relative to the blocked surface.

2. The method of claim 1, wherein the blocking reagent is an alkene.

3. The method of claim 1, wherein the blocking reagent is an alkylsilylhalide having a chemical structure

4. The method of claim 1, wherein the exposed silicon oxide surface comprises hydroxyl groups.

5. The method of claim 1, further comprising, after selectively depositing the silicon nitride, removing the organic moiety.

6. The method of claim 5, wherein removing the organic moiety comprises exposing the semiconductor substrate to an inert gas selected from the group consisting of helium and argon and igniting a plasma at a plasma power between about 500 W and about 2000 W.

7. The method of claim 3, further comprising, after selectively depositing the silicon nitride, removing the organic moiety by exposing the semiconductor substrate to a mixture of a fluorine-containing gas and an oxygen-containing gas and igniting a plasma at a plasma power between about 75 W and about 200 W.

8. The method of claim 1, further comprising, prior to exposing the semiconductor substrate to the blocking reagent, exposing the semiconductor substrate to hydrogen to form hydrogenated groups on the exposed silicon surface.

9. The method of claim 1, wherein the silicon-containing precursor is selected from the group consisting of silicon halides and aminosilanes.

10. The method of claim 1, wherein the nitrogen-containing reactant is ammonia, nitrogen, a hydrazine, or a combination thereof.

11. The method of claim 1, wherein the semiconductor substrate resides on a pedestal set to a temperature between about 25°

C. and about 300°

C.

12. The method of claim 1, wherein the semiconductor substrate resides in a chamber set to a chamber pressure between about 10 mTorr and about 10 Torr.

13. The method of claim 1, wherein each thermal atomic layer deposition cycle further comprises purging a chamber housing the semiconductor substrate between exposing the semiconductor substrate to the silicon-containing precursor and exposing the semiconductor substrate to the nitrogen-containing reactant.

14. The method of claim 2, wherein the alkene is 1-octadecene.

15. The method of claim 3, wherein the alkylsilylhalide is octadecyltrichlorosilane.

16. The method of claim 7, wherein the plasma is ignited in a remote plasma generator.

17. The method of claim 7, wherein the plasma is ignited in situ.