Selective tungsten removal

• US 10,256,112 B1
• Filed: 12/08/2017
• Issued: 04/09/2019
• Est. Priority Date: 12/08/2017
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Wang, Xikun, Ingle, Nitin
• Primary Examiner(s): Culbert, Roberts P
• Application Number:
  US15/835,731
• Time in Patent Office: 487 Days
• Field of Search: 216719
• CPC Class Codes: C23C 16/01 on temporary substrates, e.g. substrates subsequently removed by etching
• CPC Class Codes: C23C 28/00 Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
• CPC Class Codes: C23C 28/04 only coatings of inorganic non-metallic material
• CPC Class Codes: C23C 28/042 including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides
• CPC Class Codes: C23C 28/30 Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
• CPC Class Codes: H01L 21/02175 characterised by the metal H01L21/02197 takes precedence
• CPC Class Codes: H01L 21/28556 by chemical means, e.g. CVD, LPCVD, PECVD, laser CVD H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/31122 of layers not containing Si, e.g. PZT, Al2O3
• CPC Class Codes: H01L 21/32136 using plasmas
• CPC Class Codes: H01L 21/76865 Selective removal of parts of the layer H01L21/76844 takes precedence
• CPC Class Codes: H01L 2924/01074 Tungsten [W]

Abstract

Exemplary methods for removing tungsten-containing material may include flowing a chlorine-containing precursor into a processing region of a semiconductor processing chamber. The methods may also include flowing methane into the processing region of the semiconductor processing chamber. The methods may include forming a plasma from the chlorine-containing precursor and the methane to produce plasma effluents. The methods may also include contacting a substrate with the plasma effluents. The substrate may include an exposed region of a tungsten-containing material. The plasma effluents may produce an oxychloride of tungsten. The methods may also include recessing the exposed region of the tungsten-containing material.

Claims

1. An etching method comprising:

flowing a chlorine-containing precursor into a processing region of a semiconductor processing chamber;

flowing methane into the processing region of the semiconductor processing chamber;

forming a plasma from the chlorine-containing precursor and the methane to produce plasma effluents;

contacting a substrate with the plasma effluents, wherein the substrate comprises an exposed region of a tungsten-containing material, and wherein the plasma effluents produce an oxychloride of tungsten; and

recessing the exposed region of the tungsten-containing material.

2. The etching method of claim 1, wherein the tungsten-containing material comprises at least one of tungsten oxide or tungsten metal.

3. The etching method of claim 1, wherein the etching method removes the tungsten-containing material at a rate of at least about 200 Å

per minute.

4. The etching method of claim 3, wherein the etching method removes the tungsten-containing material at a rate of at least about 400 Å

per minute.

5. The etching method of claim 1, wherein the substrate further comprises an exposed region of a silicon-containing material, and wherein the etching method has a selectivity of the tungsten-containing material to the silicon-containing material greater than or about 100:

1.

6. The etching method of claim 5, wherein the silicon-containing material defines a trench within which at least a portion of the tungsten-containing material is disposed, the trench having an aspect ratio of about 10:

1 or greater, and wherein the etching method completely removes at least the portion of the tungsten-containing material disposed within the trench.

7. The etching method of claim 1, wherein a temperature of the substrate is maintained between about 200°

C. and about 400°

C. during the etching method.

8. The etching method of claim 7, wherein the temperature of the substrate is maintained at about 250°

C. during the etching method.

9. The etching method of claim 1, wherein a plasma power of the plasma formed from the chlorine-containing precursor and the methane is at least about 5 W.

10. The etching method of claim 1, wherein a plasma power of the plasma formed from the chlorine-containing precursor and the methane is less than or about 250 W.

11. The etching method of claim 1, wherein a pressure within the semiconductor processing chamber is maintained below or about 3 Torr.

12. The etching method of claim 1, wherein the etching method is repeated for at least two cycles.

13. The etching method of claim 12, wherein each of the at least two cycles lasts less than or about 30 seconds.

14. The etching method of claim 1, wherein a flow rate of the methane is below or about 30 sccm.

15. The etching method of claim 1, wherein the chlorine-containing precursor comprises diatomic chlorine.

16. The etching method of claim 15, wherein a flow rate of the diatomic chlorine is about 120 sccm.

17. An etching method comprising:

flowing a chlorine-containing precursor into a processing region of a semiconductor processing chamber;

flowing a hydrocarbon precursor into the processing region of the semiconductor processing chamber;

forming a plasma from the chlorine-containing precursor and the hydrocarbon precursor to produce plasma effluents;

contacting a substrate with the plasma effluents, wherein the substrate comprises a first region of a tungsten-containing material and a second region of a first silicon-containing material, and wherein the substrate further comprises a metal nitride liner interposed between a third region of the tungsten-containing material and a fourth region of a second silicon-containing material;

selectively etching the first region of the tungsten-containing material relative to the second region of the first silicon-containing material; and

selectively etching the metal nitride liner relative to the first and the second silicon-containing material.

18. The etching method of claim 17, wherein the plasma effluents produce an oxychloride of tungsten.

19. An etching method comprising:

flowing diatomic chlorine at less than or about 250 sccm into a processing region of a semiconductor processing chamber;

flowing methane at less than or about 50 sccm into the processing region of the semiconductor processing chamber;

forming a plasma from the diatomic chlorine and the methane at a plasma power of between about 10 W and about 250 W to produce plasma effluents;

contacting a substrate with the plasma effluents, wherein the substrate comprises an exposed region of a tungsten-containing material and an exposed region of a silicon-containing material;

etching the exposed region of the tungsten-containing material at a rate of at least about 400 Å

per minute, wherein the etching method has a selectivity of the tungsten-containing material to the silicon-containing material greater than 100;

1;

wherein a temperature of the substrate is maintained at about 250°

C. during the etching of the exposed region of the tungsten-containing material; and

wherein a pressure of the semiconductor processing chamber is maintained at or below about 10 Torr during the etching of the exposed region of the tungsten-containing material.