METHOD OF FORMING A SEMICONDUCTOR DEVICE WITH AIR GAPS FOR LOW CAPACITANCE INTERCONNECTS

• US 20190311947A1
• Filed: 04/09/2019
• Published: 10/10/2019
• Est. Priority Date: 04/09/2018
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Tapily, Kandabara, Tsunomura, Takaaki
• Granted Patent: US 11,251,077 B2
• Time in Patent Office: Days
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/402 Silicon dioxide
• CPC Class Codes: C23C 16/45534 Use of auxiliary reactants other than used for contributing to the composition of the main film, e.g. catalysts, activators or scavengers
• CPC Class Codes: C23C 16/4554 Plasma being used non-continuously in between ALD reactions C23C16/56 takes precedence
• CPC Class Codes: C23C 16/45553 characterized by the use of precursors specially adapted for ALD
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02186 the material containing titanium, e.g. TiO2
• CPC Class Codes: H01L 21/02216 the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• 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 21/764 Air gaps H01L21/76264 takes precedence
• CPC Class Codes: H01L 21/7682 the dielectric comprising air gaps
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material

Abstract

A method of fabricating air gaps in advanced semiconductor devices for low capacitance interconnects. The method includes exposing a substrate to a gas pulse sequence to deposit a material that forms an air gap between raised features.

Claims

1. A substrate processing method, comprising:

providing a substrate containing raised features with top areas and sidewalls, and bottom areas between the raised features; and

exposing the substrate to a gas pulse sequence to deposit a material that forms an air gap between the raised features, wherein the gas pulse sequence includes, in any order;

a) sequentially first, exposing the substrate to a first precursor gas to non-conformally form a first precursor layer on the top areas and on the upper parts of the sidewalls, but not on the lower parts of the sidewalls and the bottom areas, and second, exposing the substrate to a second precursor gas that reacts with the first precursor layer to form a first layer of the material on the substrate, and

b) sequentially first, exposing the substrate to the first precursor gas to conformally form a second precursor layer on the top areas, on the sidewalls, and on the bottom areas, and second, exposing the substrate to the second precursor gas that reacts with the second precursor layer to form a second layer of the material on the substrate.

2. The method of claim 1, further comprising

repeating steps a), b), or a) and b), at least once until the air gap is formed.

3. The method of claim 1, wherein the first precursor gas contains a metal-containing precursor.

4. The method of claim 1, wherein the first precursor contains aluminum, titanium, or a combination thereof.

5. The method of claim 3, wherein the precursor layers are selected from the group consisting of Al, Al₂O₃, AlN, AlON, an Al-containing precursor, Al-alloys, CuAl, TiAlN, TaAlN, Ti, TiAlC, TiO₂, TiON, TiN, a Ti-containing precursor, Ti-alloys, and combinations thereof.

6. The method of claim 1, wherein the first and second layers of the material contain SiO₂.

7. The method of claim 1, wherein the second precursor gas includes a silanol gas.

8. The method of claim 7, wherein the silanol gas is selected from the group consisting of tris(tert-pentoxy) silanol, tris(tert-butoxy) silanol, and bis(tert-butoxy)(isopropoxy) silanol.

9. The method of claim 1, wherein first precursor contains AlMe₃ and the second precursor contains tris(tert-pentoxy) silanol.

10. The method of claim 1, wherein the exposing the substrate to the second precursor gas includes:

in the absence of any oxidizing and hydrolyzing agent, exposing the substrate at a substrate temperature of approximately 150°

C. or less, to a process gas containing a silanol.

11. A substrate processing method, comprising:

providing a substrate containing raised features with top areas and sidewalls, and bottom areas between the raised features; and

exposing the substrate to a gas pulse sequence to deposit a material that forms an air gap between the raised features, wherein the gas pulse sequence includes, in any order;

a) sequentially first, exposing the substrate to a first precursor gas to conformally form a first precursor layer on the top areas, on the sidewalls, and on the bottom areas, second, exposing the substrate to a plasma-excited halogen-containing gas to deactivate or at least partially remove the first precursor layer in the top areas and the bottom areas, and third, exposing the substrate to the second precursor gas that reacts with the precursor layer to form a first layer of the material on the sidewalls, and

b) sequentially first, exposing the substrate to the first precursor gas to conformally form a second precursor layer on the top areas, on the sidewalls, and on the bottom areas, and second, exposing the substrate to the second precursor gas that reacts with the second precursor layer form a second layer of the material on the substrate.

12. The method of claim 11, further comprising

repeating steps a), b), or a) and b), at least once until the air gap is formed.

13. The method of claim 11, wherein the first precursor gas contains a metal-containing precursor.

14. The method of claim 11, wherein the first precursor contains aluminum, titanium, or a combination thereof.

15. The method of claim 14, wherein the precursor layers are selected from the group consisting of Al, Al₂O₃, AlN, AlON, an Al-containing precursor, Al-alloys, CuAl, TiAlN, TaAlN, Ti, TiAlC, TiO₂, TiON, TiN, a Ti-containing precursor, Ti-alloys, and combinations thereof.

16. The method of claim 11, wherein the first and second layers of the material contain SiO₂.

17. The method of claim 11, wherein the second precursor gas includes a silanol gas.

18. The method of claim 17, wherein the silanol gas is selected from the group consisting of tris(tert-pentoxy) silanol, tris(tert-butoxy) silanol, and bis(tert-butoxy)(isopropoxy) silanol.

19. The method of claim 11, wherein the exposing the substrate to the second precursor gas includes:

in the absence of any oxidizing and hydrolyzing agent, exposing the substrate at a substrate temperature of approximately 150°

C. or less, to a process gas containing a silanol.

20. The method of claim 11, wherein the plasma-excited halogen-containing gas includes Cl₂, BCl₃, CCl₄, HCl, HBr, or TiCl₄, or a combination thereof.