Trench isolation process to deposit a trench fill oxide prior to sidewall liner oxidation growth

• US 6,387,764 B1
• Filed: 03/31/2000
• Issued: 05/14/2002
• Est. Priority Date: 04/02/1999
• Status: Expired due to Fees

• Current Assignee: Avid Technology Incorporated
• Original Assignee: Silicon Valley Group Thermal Systems LLC (ASML Holding NV)
• Inventors: Rao, Vivek, Kapkin, Kerem, Curtis, Todd O.
• Primary Examiner(s): Niebling, John F.
• Assistant Examiner(s): JONES, JOSETTA I
• Application Number:
  US09/541,395
• Time in Patent Office: 774 Days
• Field of Search: 438/404, 438/424, 438/296
• US Class Current: 438/296
• 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 21/76229 Concurrent filling of a plurality of trenches having a different trench shape or dimension, e.g. rectangular and V-shaped trenches, wide and narrow trenches, shallow and deep trenches

Abstract

This invention relates generally to a method of trench isolation used in the fabrication of semiconductor devices, wafers and the like. More specifically, the present invention related to a method of trench isolation using chemical vapor deposition (CVD) with TEOS and ozone to deposit a trench fill oxide prior to growing a thermal oxide layer or liner on sidewalls of the trench. The method provides void-free as-deposited dielectric CVD films into gaps or trenches with non-vertical, vertical and or re-entrant profiles.

Claims

1. A trench isolation method characterized in that a trench fill oxide layer is deposited on a substrate having trenches with sidewalls by chemical vapor deposition (CVD) using a silicon containing gas and ozone, said trench fill oxide layer is deposited prior to growth of a thermal oxide on the sidewalls of the trench, and where said trench fill oxide layer is deposited to form either a selective or non-selective oxide layer on the substrate.

2. The method of claim 1 wherein said method is carried out at a pressure in the range of about 200 Torr to 1200 Torr.

3. The method of claim 1 wherein said trench fill oxide layer includes etched silicon trenches with a top layer of hydrophilic material such as Si₃N₄ or thermal oxide.

4. The method of claim 1 wherein the substrate includes a semiconductor structure entirely over-coated with Si₃N₄.

5. The method of claim 1 wherein the substrate includes a semiconductor structure entirely over-coated with polysilicon epitaxial layer.

6. The method of claim 1 wherein said trench fill oxide is substantially planar.

7. A method of forming a film on the surface of a semiconductor substrate having one or more trench isolation structures with sidewalls formed thereon, comprising the steps of:

depositing an oxide film by chemical vapor deposition (CVD) using ozone and a silicon containing reactant atop the trench structures and sidewalls, and after said depositing step;

growing a thermal oxide layer on the surface of the sidewalls; and

where said depositing step is carried out to deposit either a selective or non-selective oxide film on the surface of the substrate.

8. The method of claim 7 further comprising the step of:

removing any native or chemical oxide from the sidewalls prior to said growing step.

9. The method of claim 7 wherein said growing step is carried out by annealing at a temperature in the range of about 700 to 1200°

C., for a period of time in the range of about 30 seconds to 300 minutes.

10. The method of claim 9 wherein the annealing occurs in either an oxygen or steam environment.

11. The method of claim 7 wherein said depositing step is carried out at a temperature in the range of about 300 to 600°

C., and at a pressure in the range of about 200 Torr to 1200 Torr.

12. The method of claim 7 wherein the film formed on the surface of the substrate is substantially planar.

13. The method of claim 7 wherein said depositing step is carried out with ozone and TEOS having an ozone to TEOS ratio in the range of approximately 5 to 200.

14. The method of claim 7 wherein said depositing step is carried out at a temperature in the range of approximately 350 to 450°

C., to deposit the selective oxide film on the surface of the substrate.

15. The method of claim 7 wherein said growing step is carried out in a single wafer furnace.

16. The method of claim 7 wherein said growing step is carried out in a RTP system.

17. A method of forming a film on the surface of a semiconductor substrate having one or more trench isolation structures with sidewalls formed thereon, comprising the steps of:

depositing an oxide film by chemical vapor deposition (CVD) using ozone and a silicon containing reactant atop the trench structures and sidewalls where said depositing step is carried out to deposit either a selective or non-selective oxide film on the surface of the substrate, and after said depositing step;

growing a thermal oxide layer on the surface of the sidewalls; and

densifying said oxide film deposited in the trench structure, wherein said growth of said thermal oxide layer on the surface of the sidewall and said densification of said oxide film deposited in the trench structure are performed simultaneously.