Method of programming an improved metal-to-metal via-type antifuse

• US 5,741,720 A
• Filed: 10/04/1995
• Issued: 04/21/1998
• Est. Priority Date: 10/04/1995
• Status: Expired due to Fees

• Current Assignee: Actel Corporation (Microchip Technology Incorporated)
• Original Assignee: Actel Corporation (Microchip Technology Incorporated)
• Inventors: Hawley, Frank W., Eltoukhy, Abdelshafy A., McCollum, John L.
• Primary Examiner(s): Bowers, Jr., Charles L.
• Assistant Examiner(s): GURLEY, LYNNE ANN
• Application Number:
  US08/538,962
• Time in Patent Office: 930 Days
• Field of Search: 437/60, 437/195, 437/922, 257/50, 257/530
• US Class Current: 438/467
• CPC Class Codes: H01L 23/5252 comprising anti-fuses, i.e. connections having their state changed from non-conductive to conductive
• 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 metal-to-metal antifuse disposed between two aluminum metallization layers in a CMOS integrated circuit or similar structure includes an antifuse material layer having an aluminum-free conductive link. The aluminum-free link is formed by forming a first barrier metal layer out of TiN having a first thickness, a second barrier metal layer out of TiN having a second thickness which may be less than said first thickness, the first and second barrier metal layers separating the antifuse material layer from first and second electrodes. The antifuse is programmed by applying a voltage potential capable of programming the antifuse across the electrodes with the more positive side of the potential applied to the electrode adjacent the barrier metal layer having the least thickness. In another aspect of the invention, an antifuse having a first barrier metal layer of a first thickness and a second barrier metal layer of a second thickness may be fabricated wherein the first thickness is less than the second thickness and wherein programming of the antifuse is accomplished by placing the more positive voltage of the programming voltage supply on the electrode of the antifuse adjacent the first barrier metal layer.

Claims

1. A method for forming a programmed antifuse disposed in an integrated circuit, said method comprising the steps of:

forming a lower conductive layer formed of a film of material including aluminum;

forming a lower barrier metal layer disposed over and in electrical contact with said lower conductive layer, said lower barrier metal layer having a first minimum thickness of at least 2000 Å

;

forming an antifuse material layer disposed over and in contact with said lower barrier metal layer;

forming an upper barrier metal layer disposed over and in contact with said antifuse material layer, said upper barrier metal layer having a second minimum thickness, said second minimum thickness being in the range of about 1000 Å

to about 2000 Å

;

forming an upper conductive layer formed of a film of material including aluminum, said film disposed over and in electrical contact with said upper barrier metal layer;

programming the antifuse by forming a substantially aluminum-free conductive link shorting said antifuse material layer by applying a programming signal between said lower conductive layer and said upper conductive layer, a voltage induced on said upper conductive layer referenced to said lower conductive layer being positive.

2. The method according to claim 1, said lower and upper barrier metal layers comprising TiN.

3. A method for forming a programmed antifuse disposed in an integrated circuit, said method comprising the steps of:

forming a lower conductive layer formed of a film of material including aluminum;

forming a lower barrier metal layer disposed over and in electrical contact with said lower conductive layer, said lower barrier metal layer having a first minimum thickness in the range of about 1000 Å

to about 2000 Å

;

forming an antifuse material layer disposed over and in contact with said lower barrier metal layer;

forming an upper barrier metal layer disposed over and in contact with said antifuse material layer, said upper barrier metal layer having a second minimum thickness of at least 2000 Å

; and

forming an upper conductive layer formed of a film of material including aluminum, said film disposed over and in electrical contact with said upper barrier metal layer;

programming the antifuse by forming a substantially aluminum-free conductive link shorting said antifuse material layer by applying a programming signal between said lower conductive layer and said upper conductive layer, a voltage induced on said lower conductive layer referenced to said upper conductive layer being positive.

4. The method according to claim 3, said lower and upper barrier metal layers, comprising TiN.

5. A method for forming a programmed antifuse disposed in an integrated circuit, said method comprising the steps of:

forming a lower conductive layer formed of a film of material including aluminum;

forming a lower barrier metal layer disposed over and in electrical contact with said lower conductive layer, said lower barrier metal layer having a first minimum thickness of at least about 2000 Å

;

forming an antifuse material layer disposed over and in contact with said lower barrier metal layer;

forming an upper barrier metal layer disposed over and in contact with said antifuse material layer, said upper barrier metal layer having a second minimum thickness of at least about 2000 Å

; and

forming an upper conductive layer formed of a film of material including aluminum, said film disposed over and in electrical contact with said upper barrier metal layer,

programming the antifuse by forming a substantially aluminum-free conductive link shorting said antifuse material layer by applying a programming signal between said lower conductive layer and said upper conductive layer, a voltage induced by a first portion of said programming signal on said lower conductive layer referenced to said upper conductive layer being positive and a voltage induced by a second portion of said programming signal on said lower conductive layer referenced to said upper conductive layer being negative.

6. The method according to claim 5, said lower and upper barrier metal layers comprising TiN.

7. A method of forming a programmed antifuse disposed in an integrated circuit, said method comprising the steps of:

forming a lower electrode formed of a film of material including aluminum;

forming a lower barrier metal layer disposed over and in electrical contact with said lower electrode, said lower barrier metal layer having a first minimum thickness of at least about 2000 Å

;

disposing an antifuse material layer over and in contact with said lower barrier metal layer;

disposing an interdielectric layer over and in contact with said lower barrier metal layer;

forming a via having a sidewall in and through said interdielectric layer exposing a portion of said antifuse material layer;

forming an upper barrier metal layer disposed over said interdielectric layer, in said via, over said portion of said antifuse material layer and adhered to said sidewall of said via, said upper barrier metal layer having a second minimum thickness, said second minimum thickness being in the range of about 1000 Å

to about 2000 Å

;

disposing an upper electrode formed of a film of material including aluminum, said upper electrode disposed over and in electrical contact with said upper barrier metal layer;

programming the antifuse by forming a substantially aluminum-free conductive link shorting said antifuse material layer by applying a programming signal between said lower conductive layer and said upper conductive layer, a voltage induced on said upper conductive layer referenced to said lower conductive layer being positive.

8. The method according to claim 7, lower and upper barrier metal layers comprising TiN.

9. A method of forming a programmed antifuse disposed in an integrated circuit, said method comprising the steps of:

forming a lower electrode formed of a film of material including aluminum;

forming a lower barrier metal layer disposed over and in electrical contact with said lower electrode, said lower barrier metal layer having a first minimum thickness of about 1000 Å

to about 2000 Å

;

disposing an antifuse material layer over and in contact with said lower barrier metal layer;

disposing an interdielectric layer over and in contact with said lower barrier metal layer;

forming a via having a sidewall in and through said interdielectric layer exposing a portion of said antifuse material layer;

forming an upper barrier metal layer disposed over said interdielectric layer, in said via, over said portion of said antifuse material layer and adhered to said sidewall of said via, said upper barrier metal layer having a second minimum thickness, said second minimum thickness being in the range of at least about 2000 Å

;

disposing an upper electrode formed of a film of material including aluminum, said upper electrode disposed over and in electrical contact with said upper barrier metal layer;

programming the antifuse by forming a substantially aluminum-free conductive link shorting said antifuse material layer by applying a programming signal between said lower conductive layer and said upper conductive layer, a voltage induced on said lower conductive layer referenced to said upper conductive layer being positive.

10. The method according to claim 9, said lower and upper barrier metal layers comprising TiN.

11. A method of forming a programmed antifuse disposed in an integrated circuit, said method comprising the steps of:

forming a lower electrode formed of a film of material including aluminum;

forming a lower barrier metal layer disposed over and in electrical contact with said lower electrode, said lower barrier metal layer having a first minimum thickness of at least about 2000 Å

;

disposing an antifuse material layer over and in contact with said lower barrier metal layer;

disposing an interdielectric layer over and in contact with said lower barrier metal layer;

forming a via having a sidewall in and through said interdielectric layer exposing a portion of said antifuse material layer;

forming an upper barrier metal layer disposed over said interdielectric layer, in said via, over said portion of said antifuse material layer and adhered to said sidewall of said via, said upper barrier metal layer having a second minimum thickness, said second minimum thickness being in the range of at least about 2000 Å

;

disposing an upper electrode formed of a film of material including aluminum, said upper electrode disposed over and in electrical contact with said upper barrier metal layer;

programming the antifuse forming a substantially aluminum-free conductive link shorting said antifuse material layer by applying a programming signal between said lower conductive layer and said upper conductive layer, a voltage induced by a first portion of said programming signal on said lower conductive layer referenced to said upper conductive layer being positive and a voltage induced by a second portion of said programming signal on said lower conductive, layer referenced to said upper conductive layer being negative.

12. The method according to claim 11, said lower and upper barrier metal layers comprising TiN.