Selective etching of unreacted nickel after salicidation

Details Selective etching of unreacted nickel after salicidation Selective etching of unreacted nickel after salicidation

2000-06-21

2001-05-01

Quach, T. N. (Department: 2814)

Semiconductor device manufacturing: process

Coating with electrically or thermally conductive material

Insulated gate formation

C438S655000, C438S683000, C438S721000

Reexamination Certificate

active

06225202

ABSTRACT:

BACKGROUND OF THE INVENTION
(1) Field of the Invention
The invention relates to the fabrication of integrated circuit devices, and more particularly, to a method of removing unwanted nickel or cobalt in the fabrication of integrated circuits.
(2) Description of the Prior Art
In the fabrication of integrated circuits, metal silicides are often formed through a rapid thermal annealing (RTA) process. Metals such as titanium, cobalt, and nickel are typically used in salicidation. After RTA, the unreacted metal is typically removed by wet chemicals. For example, SC-1 (Standard Clean-1 comprising ammonium hydroxide, hydrogen peroxide, and de-ionized water) may be used to remove titanium, SC-2 (Standard Clean-2 comprising hydrochloric acid, hydrogen peroxide, and de-ionized water) and a mixture of sulfuric acid, hydrogen peroxide, and water (SPM) may be used to remove cobalt and nickel. Nitric acid and SPM are also used for the stripping (rework) of cobalt and nickel on bare silicon wafers. The drawbacks of using wet chemicals include the expensiveness of high purity chemicals, disposal costs, and the corrosive nature of the chemicals.
U.S. Pat. No. 4,659,426 to Fuller et al teaches using a carbonyl source for etching a metal, metal silicide, or polysilicon. U.S. Pat. No. 5,358,601 to Cathey shows the etching of a polycide using CO
2
and a halogen-containing gas. U.S. Pat. No. 5,259,923 to Hori et al etches the polysilicon layer of a polycide using carbon monoxide. U.S. Pat. No. 5,091,050 to Fujino et al etches aluminum and a transition metal using carbon monoxide.
SUMMARY OF THE INVENTION
A principal object of the present invention is to provide an effective and very manufacturable method of removing unreacted metal after salicidation using dry etching.
A further object of the invention is to provide a method of removing unwanted metal using carbon monoxide dry stripping.
Yet another object is to provide a method of removing unreacted nickel or cobalt after salicidation using carbon monoxide dry stripping.
Yet another object is to provide a method of removing unwanted nickel or cobalt using carbon monoxide dry stripping.
In accordance with the objects of the invention a method for removing unwanted nickel or cobalt using carbon monoxide dry stripping in the manufacture of an integrated circuit is achieved. A nickel or cobalt layer on a substrate is exposed to a plasma containing carbon monoxide gas wherein the carbon monoxide gas reacts with the metal thereby removing the metal from the substrate.
Also in accordance with the objects of the invention a method for removing unreacted nickel or cobalt after salicidation using carbon monoxide dry stripping is achieved. Shallow trench isolation regions are formed in a semiconductor substrate surrounding and electrically isolating an active area from other active areas. A gate electrode and associated source and drain regions are formed in the active area wherein dielectric spacers are formed on sidewalls of the gate electrode. A nickel or cobalt layer is deposited over the gate electrode and associated source and drain regions. The semiconductor substrate is annealed whereby the nickel or cobalt layer overlying the gate electrode and said source and drain regions is transformed into a nickel or cobalt silicide layer and wherein the nickel or cobalt layer overlying the dielectric spacers and the shallow trench isolation regions is unreacted. The unreacted nickel or cobalt layer is exposed to a plasma containing carbon monoxide gas wherein the carbon monoxide gas reacts with the unreacted nickel or cobalt thereby removing the unreacted nickel or cobalt from the substrate to complete salicidation of the integrated circuit device.


REFERENCES:
patent: 4659426 (1987-04-01), Fuller et al.
patent: 5091050 (1992-02-01), Fujino et al.
patent: 5259923 (1993-11-01), Hori et al.
patent: 5358601 (1994-10-01), Cathey
patent: 10-150044 (1998-06-01), None

Affiliated with

Also associated with

Rating

Selective etching of unreacted nickel after salicidation does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Selective etching of unreacted nickel after salicidation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Selective etching of unreacted nickel after salicidation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2551896