PECVD flowable dielectric gap fill

• US 8,557,712 B1
• Filed: 12/15/2008
• Issued: 10/15/2013
• Est. Priority Date: 12/15/2008
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Antonelli, George Andrew, Van Schravendijk, Bart
• Primary Examiner(s): Maldonado, Julio J
• Assistant Examiner(s): SHOOK, DANIEL P
• Application Number:
  US12/334,726
• Time in Patent Office: 1,765 Days
• Field of Search: 257E2126-E21263, 427/489, 427/579, 438/761, 438/780, 438/781, 438/789
• US Class Current: 438/761
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/30 Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
• CPC Class Codes: C23C 16/509 using internal electrodes
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• 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 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264
• CPC Class Codes: H01L 21/76825 by exposing the layer to particle radiation, e.g. ion implantation, irradiation with UV light or electrons etc. plasma treatment H01L21/76826
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76828 thermal treatment
• CPC Class Codes: H01L 21/76837 Filling up the space between adjacent conductive structures; Gap-filling properties of dielectrics
• CPC Class Codes: H01L 23/5329 Insulating materials
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

New methods of filling gaps with dielectric material are provided. The methods involve plasma-enhanced chemical vapor deposition (PECVD) of a flowable polymerized film in a gap, followed by an in-situ treatment to convert the film to a dielectric material. According to various embodiments, the in-situ treatment may be a purely thermal or plasma treatment process. Unlike conventional PECVD processes of solid material, which deposit film in a conformal process, the deposition results in bottom-up fill of the gap. In certain embodiments, a deposition-in situ treatment-deposition-in situ treatment process is performed to form dielectric layers in the gap. The sequence is repeated as necessary for bottom up fill of the gap. Also in certain embodiments, an ex-situ post-treatment process is performed after gap fill is completed. The processes are applicable to frontend and backend gapfill.

Claims

1. A method of filling gaps on a substrate with dielectric material comprising:

placing the substrate in a reaction chamber;

introducing a process gas comprising a silicon-containing compound and an oxidant into the reaction chamber, wherein the oxidant is selected from oxygen (O₂) and ozone (O₃);

exposing the substrate to a plasma generated from the process gas under conditions, including a substrate temperature of between about 60°

C. and 100°

C., such that the silicon-containing compound and the oxidant plasma species react and condense such that an amorphous flowable organo-silicon polymer film is thereby deposited to partially fill the gaps via a substantially-high frequency-only HF capacitatively-coupled plasma-assisted reaction;

converting the flowable film to a dielectric material via an in-situ treatment process; and

repeating the exposure and conversion operations at least once to fill the gaps.

2. The method of claim 1 further comprising transferring the substrate to a cure chamber and performing an ex-situ treatment process.

3. The method of claim 2 wherein the in-situ and ex-situ treatment processes remove substantially all of the carbon from the as-deposited flowable organosilicon film.

4. The method of claim 2 wherein the ex-situ treatment process comprises an ultraviolet thermal processing operation at a substrate temperature of at least about 400°

C.

5. The method of claim 2 wherein the ex-situ treatment process comprises an thermal processing operation at a substrate temperature of at least about 700°

C.

6. The method of claim 1 wherein silicon-containing compound is an organo-silane or an organo-siloxane.

7. The method of claim 1 wherein at least one gap has an aspect ratio of at least bout 10:

1.

8. The method of claim 1 wherein at least one gap has an aspect ratio of at least about 15:

1.

9. The method of claim 1 wherein the in-situ treatment process comprises exposing the film to an inert plasma, wherein the inert plasma is generated only from inert gases.

10. The method of claim 9 wherein the in-situ treatment process comprises exposing the film to an oxidizing plasma.

11. The method of claim 1 wherein the in-situ treatment process removes at least some of the carbon from the flowable organosilicon film.

12. The method of claim 1 wherein exposing the substrate to the process gas under conditions such that a flowable organo-silicon polymer film is deposited to partially fill the gaps via a capacitatively-coupled plasma-assisted reaction comprises pulsing the RF frequency.

13. The method of claim 1 wherein the deposited film in the gap comprises interfaces between sequentially deposited layers in the gap.

14. The method of claim 13 wherein the film in each gap comprises at least four interfaces.

15. The method of claim 1 wherein the dielectric constant of the film is between about 2.7 and 3.0.

16. The method of claim 1 wherein the ratio of S—

CH_x peaks to the Si—

O peak is approximately 4% of the as-deposited flowable organosilicon polymer.

17. The method of claim 1 wherein the ratio of S—

CH₃ peak to the Si—

O peak is approximately 7% of the as-deposited flowable organosilicon polymer.

18. The method of claim 1 further comprising pre-treating the substrate prior to depositing of the flowable film.

19. A method of filling gaps on a substrate with dielectric material comprising:

introducing a process gas comprising a silicon-containing compound and an oxidant into the reaction chamber containing the substrate;

exposing the substrate in an exposure operation to a plasma generated from the process gas under conditions such that an amorphous flowable organo-silicon polymer film is deposited to partially fill the gaps via a plasma-assisted reaction; and

exposing the flowable organo-silicon polymer film in a treatment operation to an in-situ inert plasma, wherein the inert plasma is generated only from inert gases;

repeating the exposure and treatment operations at least once to fill the gaps.

20. The method of claim 19 wherein the inert plasma is a He plasma.

21. A method of filling gaps on a substrate with dielectric material comprising:

introducing a process gas comprising a silicon-containing compound and an oxidant into a reaction chamber housing the substrate, wherein the oxidant is selected from oxygen (O₂) and ozone (O₃);

exposing the substrate to a plasma generated from the process gas under conditions such that the silicon-containing compound and the oxidant plasma species react and condense such that an amorphous flowable organo-silicon polymer film is thereby deposited to partially fill the gaps via a substantially-high frequency-only HF plasma-assisted reaction.