Semiconductor devices and methods to form a contact in a semiconductor device
Semiconductor devices and methods to form a contact of a semiconductor device are disclosed. An example method to form a contact includes forming an insulating layer on a substrate; etching the insulating layer to form a contact hole; depositing a silicon layer on sidewalls and an undersurface of the contact hole; forming a silicon spacer on the sidewalls of the contact hole by etching the silicon layer; transforming the silicon spacer to a silicon nitride spacer; depositing a diffusion barrier on the silicon nitride spacer; and filling the contact hole with tungsten. Because the silicon nitride spacer formed on the sidewalls of the contact hole can serve as a leakage current blocking layer, the yield and the reliability of the semiconductor devices manufactured by this example process are enhanced.
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This patent arises from a divisional application of U.S. application Ser. No. 10/721,978, which was filed on Nov. 25, 2003.
FIELD OF THE DISCLOSUREThis disclosure relates generally to semiconductor devices, and, more particularly, to methods to form a contact of a semiconductor device.
BACKGROUNDAs is well known, the demand for semiconductor devices has been increasing. Various types of contacts, (e.g., contact holes), have been recently developed for semiconductor devices. The contact hole is usually filled with a conductive metal, (e.g., tungsten), to thereby electrically connect a silicon substrate with a wiring board.
An insulating layer is formed on a substrate 1. The insulating layer is then etched to thereby form a contact hole 2. An active region of the substrate 1 is exposed through the contact hole 2. A tungsten diffusion barrier 3, (e.g., a CVD TiN (chemical vapor deposition titanium nitride) layer), is deposited on the sidewalls and an undersurface of the contact hole 2. Thereafter, the contact hole 2 is filled with tungsten by depositing tungsten on the tungsten diffusion barrier 3 to thereby form a tungsten plug 4. Subsequently, an Al line 5 is deposited on the tungsten plug 4.
The above-mentioned deposition of the CVD TiN layer is usually executed by a MOCVD (metal-organic chemical vapor deposition) method. As a result, many impure atoms, (e.g., C, N, O and the like), are left in the CVD TiN layer. Leakage current can flow through these impure atoms. To reduce the leakage current, attributes of the CVD TiN layer may be enhanced by performing an N2/H2 plasma treatment. That is, the impure atoms in the CVD TiN layer can be reduced by the N2/H2 plasma treatment.
However, because of the anisotropic property of the N2/H2 plasma treatment, the sidewalls of the contact hole 2 cannot be treated with the N2/H2 plasma treatment. Since the attributes of the sidewalls of the contact hole 2 are not enhanced by the N2/H2 plasma treatment, the leakage current may flow through the sidewalls. Therefore, the yield and the reliability of the manufactured semiconductor devices are degraded.
BRIEF DESCRIPTION OF THE DRAWINGS
As shown in
Thereafter, as shown in
Thereafter, as shown in
It is also possible that, instead of the NH3 plasma treatment, the SiN spacer 8 can be formed by annealing the SiN spacer 7 through a N2 or NH3 gas atmosphere heat treatment. It is preferable that the rate of N2 or NH3 gas injected into the chamber is about 5˜20 slm and the temperature range in the chamber is about 600˜800° C.
Thereafter, as shown in
As shown in
From the foregoing, persons of ordinary skill in the art will appreciate that example semiconductor devices having a contact hole with a leakage current blocking layer and example methods for forming a contact with a SiN (silicon nitride) layer serving as a leakage current blocking layer deposited on sidewalls of the contact hole have been disclosed.
An example method for forming a contact includes: forming an insulating layer on a substrate; etching the insulating layer to form a contact hole; depositing a silicon layer on sidewalls and an undersurface of the contact hole; forming a silicon spacer on the sidewalls of the contact hole by etching the silicon layer anisotropically in a chamber; transforming the silicon spacer into a silicon nitride spacer by plasma treatment in the chamber; depositing a diffusion barrier on the silicon nitride spacer; and filling the contact hole with tungsten.
An example method for forming a contact includes: forming an insulating layer on a substrate; etching the insulating layer to form a contact hole; depositing a silicon layer on sidewalls and an undersurface of the contact hole; forming a silicon spacer on the sidewalls of the contact hole by etching the silicon layer anisotropically in a chamber; forming a silicon nitride spacer by annealing the silicon spacer through a N2 or NH3 gas atmosphere heat treatment in the chamber; depositing a diffusion barrier on the silicon nitride spacer; and filling the contact hole with tungsten.
Although certain example methods and apparatus have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.
Claims
1. A semiconductor device comprising:
- a silicon substrate;
- an insulating layer formed on the silicon substrate, the insulating layer including a contact hole formed therein;
- a silicon nitride spacer for blocking leakage current on sidewalls of the contact hole;
- a conductive material diffusion barrier layer on the silicon nitride spacer and an undersurface of the contact hole; and
- a conductive metal deposited on the diffusion barrier layer in the contact hole to thereby fill the contact hole.
2. A semiconductor device as defined in claim 1, wherein the silicon nitride spacer is formed by nitrifying a silicon spacer.
3. A semiconductor device as defined in claim 2, wherein the silicon nitride spacer is formed by NH3 plasma treating a silicon spacer.
4. A semiconductor device as defined in claim 2, wherein the silicon nitride spacer is formed by annealing a silicon spacer through a N2 or NH3 gas atmosphere heat treatment.
5. A semiconductor device as defined in claim 1, wherein the conductive material diffusion barrier layer is a CVD TiN layer.
6. A semiconductor device as defined in claim 1, wherein the conductive material diffusion barrier layer has a thickness of at least 25-150 Å.
7. A semiconductor device as defined in claim 1, wherein the silicon nitride spacer has a thickness of about 50-200 Å.
8. A semiconductor device as defined in claim 1, wherein the conductive metal includes tungsten.
Type: Application
Filed: Apr 27, 2005
Publication Date: Aug 25, 2005
Applicant:
Inventors: Byung Jung (Seoul), Bo Seo (Seoul)
Application Number: 11/115,516