Method for fabricating a thick copper line and copper inductor resulting therefrom

• US 7,776,705 B2
• Filed: 09/06/2006
• Issued: 08/17/2010
• Est. Priority Date: 09/06/2006
• Status: Active Grant

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Oladeji, Isaiah O., Cuthbertson, Alan
• Primary Examiner(s): Richards; N Drew
• Assistant Examiner(s): Withers; Grant S
• Application Number:
  US11/470,552
• Publication Number:
  US 20080057658A1
• Time in Patent Office: 1,441 Days
• Field of Search: 438/238, 438/381, 257/531
• US Class Current: 438/381
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence
• CPC Class Codes: H01L 21/76885 By forming conductive members before deposition of protective insulating material, e.g. pillars, studs
• CPC Class Codes: H01L 23/5227 Inductive arrangements or effects of, or between, wiring layers other inductive arrangements H01L23/645
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 28/10 Inductors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method of forming one or more inductors on a substrate is disclosed. The method includes forming a first dielectric material over the substrate, forming a trench in the first dielectric material, and substantially filling the trench with copper to form the one or more inductors. The first dielectric material is removed and a second dielectric material is formed over the copper. The second dielectric material is removed from an uppermost portion of the copper, thus leaving a portion of the second dielectric material on the sidewalls of the copper.

Claims

1. A method of forming one or more inductors on a substrate, the method comprising:

forming a plurality of integrated circuits on the substrate;

forming a metal layer over the plurality of integrated circuits;

forming a passivation layer over the metal layer and the plurality of integrated circuits;

forming a plurality of openings in the passivation layer thereby exposing a portion of the metal layer;

forming a copper barrier layer over the passivation layer and the plurality of passivation layer openings;

forming a photoresist layer over the copper barrier layer;

anisotropically etching the photoresist layer to form at least one trench;

substantially filling the at least one trench with a copper material to form a copper layer having at least one inductor portion, each inductor portion having an uppermost portion;

removing the photoresist layer;

annealing the copper layer;

forming a dielectric material over the copper layer;

removing horizontal sections of the dielectric material including the dielectric material from the uppermost portion of each inductor portion of the copper layer thus leaving a vertical portion of the dielectric material on sidewalk of each inductor portion; and

etching through portions of the copper barrier layer contained within the plurality of passivation layer openings to expose the metal layer.

2. The method of claim 1 further comprising forming a copper seed layer over the copper barrier layer prior to the step of substantially filling the at least one trench with the copper material.

3. The method of claim 1 wherein the dielectric layer is silicon nitride.

4. The method of claim 1 wherein the at least one trench is formed in a spiral pattern.

5. The method of claim 1 wherein the at least one trench is formed in a serpentine pattern.

6. The method of claim 1, wherein the copper layer is annealed at a temperature of between about 150°

C. and about 200°

C. in a nitrogen/hydrogen ambient.

7. A method of forming one or more inductors on a substrate, the method comprising:

forming a photoresist layer over the substrate;

anisotropically etching the photoresist layer to form a trench;

substantially filling the trench with a copper material;

removing the photoresist layer;

annealing the copper material;

forming a thin silicon nitride layer, wherein the silicon nitride layer ranges from 100 angstroms to 500 angstroms in thickness over the copper material; and

removing horizontal sections of the thin silicon nitride layer to expose an uppermost portion of the copper material and thus to leave vertical portions of the thin silicon nitride layer on sidewalk of the copper material, the vertical portions having a thickness within a range from 100 to 500 angstroms.

8. A method of forming one or more inductors on a substrate, the method comprising:

forming a photoresist layer over the substrate;

anisotropically etching the photoresist layer to form at least one trench in the photoresist layer;

substantially filling the at least one trench with a copper material to form a copper layer having at least one inductor portion, each inductor portion having an uppermost portion;

removing the photoresist layer;

annealing the copper layer;

forming a dielectric material over the copper layer;

removing horizontal sections of the dielectric material including removing the dielectric material from the uppermost portion of each inductor portion of the copper layer thus leaving vertical portions of the dielectric material sidewalls of each inductor portion

forming a Ruthenium-based seedless layer on the substrate before forming the photoresist layer, the Ruthenium-based seedless layer to form a copper barrier layer;

wherein the photoresist layer is formed over the Ruthenium-based seedless layer; and

wherein substantially filling the at least one trench comprises electroplating the Ruthenium-based seedless layer to grow copper layers within the at least one trench.

9. The method of claim 8, wherein the copper layer is annealed at a temperature of between about 150°

C. and about 200°

C. in a nitrogen/hydrogen ambient.

10. The method of claim 8 wherein the at least one trench is formed by patterning and etching the photoresist layer.

11. The method of claim 8 wherein the dielectric material is silicon nitride.

12. The method of claim 8 wherein the at least one trench is formed in a spiral pattern.

13. The method of claim 8 wherein the at least one trench is formed in a serpentine pattern.

14. A method of forming one or more inductors on a substrate, the method comprising:

forming a photoresist layer over the substrate;

anisotropically etching the photoresist layer to form at least one trench in the photoresist layer;

substantially filling the at least one trench with a copper material to form a copper layer having at least one inductor portion, each inductor having an uppermost portion;

removing the photoresist layer;

annealing the copper layer;

forming a dielectric material over the copper layer;

removing horizontal sections of the dielectric material including removing the dielectric material from the uppermost portion of each inductor portion of the copper layer thus leaving vertical portions of the dielectric material sidewalls of each inductor portion

forming a copper barrier layer on the substrate before forming the photoresist layer;

forming a copper seed layer having a thickness from 400 angstroms to 2000 angstroms on the substrate;

wherein the photoresist layer is formed on the copper seed layer; and

wherein substantially filling the at least one trench comprises electroplating the copper seed layer to grow copper layers within the at least one trench.