Method of etching dielectric layers using a removable hardmask

• US 6,458,516 B1
• Filed: 04/18/2000
• Issued: 10/01/2002
• Est. Priority Date: 12/12/1997
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Ye, Yan, Yuan, Jie, Ionov, Pavel, Zhao, Allen, Yan, Chun, Hsieh, Peter, Ma, Diana
• Primary Examiner(s): Sherry, Michael
• Assistant Examiner(s): PERT, EVAN T
• Application Number:
  US09/551,255
• Time in Patent Office: 896 Days
• Field of Search: 430/318, 430/299, 430/310, 430/311, 430/313, 430/314, 430/322, 430/323, 430/330, 430/317, 430/269, 430/703, 430/694, 438/800
• US Class Current: 430/317
• CPC Class Codes: H01L 21/02115 the material being carbon, e.g. alpha-C, diamond or hydrogen doped carbon
• CPC Class Codes: H01L 21/02118 carbon based polymeric organic or inorganic material, e.g. polyimides, poly cyclobutene or PVC polymers per se C08G, photoresist per se G03F
• CPC Class Codes: H01L 21/0212 the material being fluoro carbon compounds, e.g.(CFx) n, (CHxFy) n or polytetrafluoroethylene
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0274 Photolithographic processes
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/31138 by dry-etching
• CPC Class Codes: H01L 21/31144 using masks
• CPC Class Codes: H01L 21/3127 Layers comprising fluoro (hydro)carbon compounds, e.g. polytetrafluoroethylene
• CPC Class Codes: H01L 21/3146 Carbon layers, e.g. diamond-like layers
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/32136 using plasmas
• CPC Class Codes: H01L 21/32139 using masks

Abstract

A method of patterning a layer of dielectric material having a thickness greater than 1,000 Å, and typically a thickness greater than 5,000 Å. The method is particularly useful for forming a high aspect ratio via or a high aspect ratio contact including self-aligned contact structures, where the aspect ratio is typically greater than 3 and the feature size of the contact is about 0.25 μm or less. In particular, an organic, polymeric-based masking material is used in a plasma etch process for transferring a desired pattern through an underlying layer of dielectric material. The combination of masking material and plasma source gas must provide the necessary high selectivity toward etching of the underlying layer of dielectric material. The selectivity is preferably greater than 3:1, where the etch rate of the dielectric material is at least 3 times greater than the etch rate of the organic, polymeric-based masking material. The dielectric material may be inorganic, for example, silicon oxide; doped silicon oxide; carbon-containing silicon oxide; SOG; BPSG; and similar materials. The dielectric material may be also be organic, where a high temperature organic-based masking material is used for transferring a desired pattern, and the underlying dielectric material is of a chemical and structural composition which is sufficiently different from the masking material that the required selectivity is provided. In any case, the organic, polymeric-based masking material is easily removed from the substrate etch process after completion of etch without damage to underlying device structures.

Claims

1. A method of patterning semiconductor device features comprising the steps of:

(a) patterning a high-temperature inorganic masking material;

(b) transferring said pattern from an inorganic mask created in step (a) through an underlying layer of an organic, polymeric-based masking material;

(c) transferring said pattern from an organic, polymeric-based mask created in step (b) through at least one feature layer underlying said organic, polymeric-based mask, wherein said at least one feature layer comprises a dielectric material having a thickness greater than 1,000 Å

.

2. The method of claim 1, wherein said dielectric material is an inorganic dielectric material.

3. The method of claim 2, wherein said inorganic dielectric material is selected from the group consisting of silicon-comprising materials which also contain atoms of O, C, H, or N.

4. The method of claim 3, wherein said inorganic dielectric material is selected from the group consisting of silicon oxide, doped silicon oxide, silicon oxynitride, carbon-containing silicon oxide, BPSG, FSG, SOG, silicon nitride, silicon carbide, and combinations thereof.

5. The method of claim 1, wherein said dielectric material is an organic dielectric material.

6. The method of claim 5, wherein said organic dielectric material is selected from the group consisting of Poly(arylene)ethers, Poly(arylene)ether oxazoles, Parylene-N, Polyimides, Polynaphthalene-N, Polyphenyl-Quinoxalines, Polybenzoxazoles, Polyindane, Polynorborene, Polystyrene, Polyphenyleneoxide, Polyethylene, Polypropylene, divinylsiloxane bis-benzocyclobutene (BCB) α

C, α

FC, and combinations thereof.

7. The method of claim 6, wherein said organic dielectric material is a low k dielectric material selected from the group consisting of Poly(arylene)ethers, Poly(arylene)ether oxazoles, Parylene-N, Polyimides, Polynaphthalene-N, Polyphenyl-Quinoxalines, Polybenzoxazoles, Polyindane, Polynorborene, Polyphenyleneoxide, α

C, α

FC, and combinations thereof.

8. The method of claim 1, including an additional step subsequent to step (c):

(d) removing residual organic, polymeric-based masking layer material from a surface of said underlying feature layer.

9. The method of claim 1, including an additional step following step (b), said step comprising:

(b-2) removing any portion of said high-temperature inorganic masking material which remains after step (b).

10. The method of claim 1, wherein said step (b) transfer through said organic polymeric-based masking material is achieved using an anisotropic plasma etch.

11. The method of claim 1, wherein said step (c) pattern transfer is achieved using an anisotropic plasma etch.

12. The method of claim 1, wherein the ratio of the etch rate of said dielectric material to the etch rate of said organic, polymeric-based masking layer is at least 3:

1.

13. A method of patterning semiconductor device features comprising the steps of:

(a) patterning a layer of high-temperature imagable organo-silicon-based material;

(b) transferring a pattern from said patterned high-temperature organo-silicon-based layer created in step (a) through a layer of a high temperature organic-based masking material;

(c) transferring a pattern from said patterned high temperature organic-based masking material layer created in step (b) through at least one feature layer underlying said patterned high temperature organic-based material, wherein said at least one feature layer comprises a dielectric material having a thickness greater than 1,000 Å

.

14. The method of claim 13, wherein said high temperature organic-based masking material is a CVD deposited α

-C or α

-FC film.

15. The method of claim 14, wherein said CVD deposited α

-C or α

-FC film is formed from a starting material selected from the group consisting of CH₄, C₂H₂, CF₄, C₂F₆, C₄F₈, NF₃, and combinations thereof.

16. The method of claim 13, wherein said dielectric material is an inorganic dielectric material.

17. The method of claim 16, wherein said inorganic dielectric material is selected from the group consisting of silicon-comprising materials which also contain O, C, H, or N.

18. The method of claim 17, wherein said inorganic dielectric material is selected from the group consisting of silicon oxide, doped silicon oxide, silicon oxynitride, carbon-containing silicon oxide, BPSG, FSG, SOG, silicon nitride, silicon carbide, and combinations thereof.

19. The method of claim 13, wherein said dielectric material is an organic dielectric material.

20. The method of claim 14, wherein said dielectric material is an organic dielectric material.

21. The method of claim 20, wherein said organic dielectric material is selected from the group consisting of Poly(arylene)ethers, Poly(arylene)ether oxazoles, Parylene-N, Polyimides, Polynaphthalene-N, Polyphenyl-Quinoxalines, Polybenzoxazoles, Polyindane, Polynorborene, Polystyrene, Polyphenyleneoxide, Polyethylene, Polypropylene, divinylsiloxane bis-benzocyclobutene (BCB) and combinations thereof.

22. The method of claim 13, wherein residual high-temperature organic-based masking layer material present after step (b) is removed using plasma etching.

23. The method of claim 13, wherein residual high-temperature organic-based masking layer material present after step( b) is removed using a combination of enhanced physical bombardment with a chemically reactive ion component.