Method of selective coverage of high aspect ratio structures with a conformal film

• US 7,625,820 B1
• Filed: 06/21/2006
• Issued: 12/01/2009
• Est. Priority Date: 06/21/2006
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Papasouliotis, George D., Mui, Collin, Buretea, Mihai
• Primary Examiner(s): Ghyka; Alexander G
• Assistant Examiner(s): Nikmanesh; Seahvosh J
• Application Number:
  US11/473,372
• Time in Patent Office: 1,259 Days
• Field of Search: 438/597, 438/618, 438/681, 438/674, 438/677, 257/E21.553
• US Class Current: 438/677
• CPC Class Codes: C23C 14/046 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: H01L 21/02123 the material containing silicon
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02214 the compound comprising silicon and oxygen
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• 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 21/02312 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/31604 Deposition from a gas or vapour H01L21/31691, H01L21/31695 take precedence
• 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 21/76837 Filling up the space between adjacent conductive structures; Gap-filling properties of dielectrics

Abstract

Methods for forming thin dielectric films by selectively depositing a conformal film of dielectric material on a high aspect ratio structure have uses in semiconductor processing and other applications. A method for forming a dielectric film involves providing in a deposition reaction chamber a substrate having a gap on the surface. The gap has a top opening and a surface area comprising a bottom and sidewalls running from the top to the bottom. A conformal silicon oxide-based dielectric film is selectively deposited in the gap by first preferentially applying a film formation catalyst or a catalyst precursor on a portion representing less than all of the gap surface area. The substrate surface is then exposed to a silicon-containing precursor gas such that a silicon oxide-based dielectric film layer is preferentially formed on the portion of the gap surface area. The preferential application of the catalyst or catalyst precursor may occur either at the top of the gap, for example to form a sacrificial mask, or at the bottom of the gap to create a seamless and void-free gap fill.

Claims

1. A method for forming a dielectric film, the method comprising:

a) providing in a deposition reaction chamber a substrate having a gap on a surface, the gap having a top opening and a surface area comprising a bottom and sidewalls running from the top to the bottom;

b) selectively depositing a conformal silicon oxide-based dielectric film in the gap by;

i. preferentially applying a film formation catalyst or a catalyst precursor on a portion representing less than all of the gap surface area, wherein the portion of the gap surface area where the preferential application of the catalyst or catalyst precursor occurs comprises the bottom of the gap,

ii. selectively inhibiting film growth at the top of the gap with an agent, and

iii. exposing the substrate surface to a silicon-containing precursor gas such that a silicon oxide-based dielectric film layer is preferentially formed on said portion of the gap surface area.

2. The method of claim 1, wherein the agent increases the rate of cross-linking or termination in the growth process of the silica film.

3. The method of claim 2, wherein the agent is selected from the group consisting of H₂O, NH₃, HCl and metal compounds of the general formula MX₄ or M(OR)_a(OR′

)_b(OR″

)_c(OH)_d where M═

Si, Ge, Sn, PB, Ti, or Zr and X═

H or halogen and a+b+c+d=4;

a, b, c, d=0, 1, 2, 3 or 4.

4. A method for forming a dielectric film, the method comprising:

a) providing in a deposition reaction chamber a substrate having a gap on a surface, the gap having a top opening and a surface area comprising a bottom and sidewalls running from the top to the bottom;

b) selectively depositing a conformal silicon oxide-based dielectric film in the gap by;

i. preferentially applying a film formation catalyst or a catalyst precursor on a portion representing less than all of the gap surface area, wherein the portion of the gap surface area where the preferential application of the catalyst or catalyst precursor occurs comprises the bottom of the gap,

ii. selectively deactivating the catalyst or catalyst precursor at the top of the gap with an agent, and

iii. exposing the substrate surface to a silicon-containing precursor gas such that a silicon oxide-based dielectric film layer is preferentially formed on said portion of the gap surface area.

5. The method of claim 4, wherein the agent comprises plasma or intense light exposure.

6. The method of claim 4, wherein the agent comprises a replacement ligand set such that the catalyst is transformed into a less active species by reaction with the replacement ligand.

7. The method of claim 6, wherein the catalyst is TMA and a highly active Al—

CH₃ moiety on TMA is replaced by an amido group following exposure of surface-bound TMA to an a species a selected from the group consisting of ammonia, amines, mineral acids (HCl, HBr, HNO₃, H₂SO₄), and organic acids including carboxylic, phosphonic or sulphonic.

8. The method of claim 6, wherein the replacement ligand set process comprises the reaction scheme:

9. A method for forming a dielectric film, the method comprising:

a) providing in a deposition reaction chamber a substrate having a gap on a surface, the gap having a top opening and a surface area comprising a bottom and sidewalls running from the top to the bottom;

b) selectively depositing a conformal silicon oxide-based dielectric film in the gap by;

i. preferentially applying a film formation catalyst or a catalyst precursor on a portion representing less than all of the gap surface area, wherein the portion of the gap surface area where the preferential application of the catalyst or catalyst precursor occurs comprises the bottom of the gap, wherein a more active catalyst or catalyst precursor is applied at the bottom of the gap and a less active catalyst is applied at the top of the gap, and

ii. exposing the substrate surface to a silicon-containing precursor gas such that a silicon oxide-based dielectric film layer is preferentially formed on said portion of the gap surface area.