Chemical oxide removal of plasma damaged SiCOH low k dielectrics

• US 8,106,485 B2
• Filed: 03/07/2008
• Issued: 01/31/2012
• Est. Priority Date: 04/20/2006
• Status: Expired due to Fees

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: International Business Machines Corporation
• Inventors: America, William G., Johnston, Steven H., Messenger, Brian W.
• Primary Examiner(s): Smith, Zandra
• Assistant Examiner(s): JOY, JEREMY J
• Application Number:
  US12/044,245
• Publication Number:
  US 20080224273A1
• Time in Patent Office: 1,425 Days
• Field of Search: 257/622, 257/E23.002, 257/E21.577, 257/E21.579, 438/675
• US Class Current: 257/622
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/312 Organic layers, e.g. photoresist H01L21/3105, H01L21/32 take precedence; photoresists per se G03C
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors

Abstract

A structure and method for removing damages of a dual damascene structure after plasma etching. The method includes the use of sublimation processes to deposit reactive material onto the damaged regions and conditions to achieve a controlled removal of the damaged region. Furthermore a semiconductor structure includes a dual damascene structure that has been treated by the method.

Claims

1. A semiconductor device comprising:

a plasma etched damascene structure comprising a trench having sidewalls formed in an interlevel dielectric film;

a barrier layer comprising Si₃N₄ formed on a silicon wafer; and

a photoresist layer formed on the interlevel dielectric film;

wherein the sidewalls are devoid of plasma-induced damage,

the interlevel dielectric film is formed on the barrier layer, and

the sidewalls are recessed from the photoresist by an amount equal to a trimming dimension associated with a removed damaged portion, whereby damage to the sidewalls of the plasma etched damascene structure is removed by;

depositing a controlled amount of gaseous hydrofluoric acid and ammonia gas onto the sidewalls of the dual damascene structure;

forming volatile reaction products from a chemical reaction between the plasma induced damages and the deposited mixture of ammonia gas and gaseous hydrofluoric acid; and

removing the volatile reaction products.

2. The semiconductor device according to claim 1, wherein the interlevel dielectric film comprises low k material having a dielectric constant of 3.9 or less.

3. The semiconductor device according to claim 1, wherein the damage is removed by trimming the sidewalls between 1 and 25 nm.

4. The semiconductor device of claim 1, wherein the interlevel dielectric film comprises organic siloxanes.

5. The semiconductor device of claim 1, wherein the volatile reaction products are removed with a vacuum.

6. The semiconductor device of claim 1, wherein the volatile reaction products are removed with a non-reactive flushing gas.

7. The semiconductor device of claim 1, wherein the volatile reaction products are removed with a vacuum or a non-reactive flushing gas.

8. The semiconductor device of claim 1, wherein the trench extends through the barrier layer to the silicon wafer.

9. The semiconductor device according to claim 1, wherein the sidewalls are recessed from the photoresist by approximately 1 to 25 nm.

11. The semiconductor device according to claim 1, wherein sidewalls of the barrier layer are recessed from the photoresist.

12. The semiconductor device according to claim 11, wherein both the sidewalls formed in the interlevel dielectric film and the sidewalls of the barrier layer are recessed from the photoresist by approximately 1 to 25 nm.

13. The semiconductor device according to claim 11, wherein a portion of the photoresist overhangs both the sidewalls formed in the interlevel dielectric film and the sidewalls of the barrier layer.

14. The semiconductor device according to claim 1, wherein:

the interlevel dielectric film is directly on the barrier layer;

the trench extends through the barrier layer to the silicon wafer;

the sidewalls of the barrier layer are recessed from the photoresist by an amount equal to the trimming dimension associated with the removed damaged portion;

the sidewalls formed in the interlevel dielectric film and the sidewalls of the barrier layer are aligned; and

the interlevel dielectric film comprises organic siloxanes.

10. A semiconductor device comprising:

a plasma etched dual damascene structure comprising a trench having sidewalls formed in an interlevel dielectric film; and

a photoresist layer formed on the interlevel dielectric film;

wherein the sidewalls are devoid of plasma-induced damage, and

the sidewalls are recessed from the photoresist, whereby damage to the sidewalls of the plasma etched dual damascene structure is removed by;

depositing a controlled amount of gaseous hydrofluoric acid and ammonia gas onto the sidewalls of the dual damascene structure;

forming volatile reaction products from a chemical reaction between the plasma induced damages and the deposited mixture of ammonia gas and gaseous hydrofluoric acid; and

removing the volatile reaction products,

wherein the recessed sidewalls result in a portion of the photoresist forming an overhang; and

the recessed sidewalls are recessed from the photoresist by an amount equal to a trimming dimension associated with a removed damaged portion.

15. A semiconductor device comprising:

a plasma etched damascene structure comprising a trench having sidewalls formed in an interlevel dielectric film;

a photoresist layer formed on the interlevel dielectric film; and

a barrier layer on a silicon wafer,

wherein the sidewalls are devoid of plasma-induced damage,

the sidewalls are recessed from the photoresist,

the interlevel dielectric film is on and contacting the barrier layer;

the trench extends through the barrier layer to the silicon wafer;

both the sidewalls formed in the interlevel dielectric film and sidewalls of the barrier layer are recessed from the photoresist by an amount equal to a trimming dimension associated with a removed damaged portion;

the sidewalls formed in the interlevel dielectric film and the sidewalls of the barrier layer are aligned;

the interlevel dielectric film comprises organic siloxanes;

the barrier layer comprises nitride; and

damage to the sidewalls of the plasma etched damascene structure is removed by;

depositing a controlled amount of gaseous hydrofluoric acid and ammonia gas onto the sidewalls of the dual damascene structure;

forming volatile reaction products from a chemical reaction between the plasma induced damages and the deposited mixture of ammonia gas and gaseous hydrofluoric acid; and

removing the volatile reaction products.

16. A semiconductor device comprising:

a damascene structure comprising a trench having sidewalls formed in an interlevel dielectric film;

a barrier layer comprising nitride on a silicon wafer; and

a photoresist layer on the interlevel dielectric film;

wherein the sidewalls are devoid of plasma-induced damage,

the interlevel dielectric film is on the barrier layer, and

the sidewalls are recessed from the photoresist by an amount equal to a trimming dimension associated with a removed damaged portion.