LOW K DIELECTRIC SURFACE DAMAGE CONTROL

• US 20100173499A1
• Filed: 03/19/2010
• Published: 07/08/2010
• Est. Priority Date: 11/05/2003
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Tao, Hun-Jan, Liang, Mong-Song, Chen, Ryan Chia-Jen
• Granted Patent: US 8,148,270 B2
• Time in Patent Office: Days
• US Class Current: 438/735
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/76802 by forming openings in dielectrics
• CPC Class Codes: H01L 21/76807 for dual damascene structures

Abstract

A method of removing a silicon nitride or a nitride-based bottom etch stop layer in a copper damascene structure by etching the bottom etch stop layer is disclosed, with the method using a high density, high radical concentration plasma containing fluorine and oxygen to minimize back sputtering of copper underlying the bottom etch stop layer and surface roughening of the low-k interlayer dielectric caused by the plasma.

Claims

1. A method of etching a nitride-based bottom etch stop layer in a copper damascene structure comprising:

etching the nitride-based bottom etch stop layer using a high density, high radical concentration plasma containing both fluorine and oxygen, wherein the fluorine and oxygen radical to fluorine and oxygen ion ratio in the plasma is equal to or greater than about 10;

1.

2. A method according to claim 1, wherein the nitride-based bottom etch stop layer is silicon nitride.

3. A method according to claim 1, wherein the nitride-based bottom etch stop layer is oxynitride.

4. A method according to claim 1, wherein the fluorine is provided by at least one of CF₄, CHF₃, SF₆, NF₃, C₂F₆, C₄F₈, CH₂F₂, CH₃F, and C₄F₆.

5. A method according to claim 1, wherein the high density plasma further comprises N₂ and any one of inert gases.

6. A method according to claim 1, wherein the copper damascene structure is a via step.

7. A method according to claim 1, wherein the copper damascene structure is a single damascene structure.

8. A method according to claim 1, wherein the copper damascene structure is a non-intermediate etch stop layer dual damascene.