KR19990059072A - Method of forming barrier metal layer of semiconductor device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a barrier metal layer of a semiconductor device, wherein after forming a titanium (Ti) layer, the titanium layer is heat treated in a nitride gas atmosphere to form a titanium nitride (TiN) layer on a surface of the titanium layer. The present invention relates to a method of forming a barrier metal layer of a semiconductor device capable of preventing overhang of a titanium nitride layer generated during the deposition process and lowering a contact resistance.

Description

Method of forming barrier metal layer of semiconductor device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a barrier metal layer of a semiconductor device, wherein after forming a titanium (Ti) layer, the titanium layer is heat treated in a nitride gas atmosphere to form a titanium nitride (TiN) layer on a surface of the titanium layer. The present invention relates to a method of forming a barrier metal layer of a semiconductor device capable of preventing overhang of a titanium nitride layer generated during the deposition process and lowering a contact resistance.

In general, as the semiconductor devices are highly integrated, the size of the contact hole is reduced. As a result, it is difficult to satisfactorily fill the contact hole during the metal contact process, and the contact resistance is increased to reduce the electrical characteristics of the device. In order to solve this problem, titanium (Ti) and titanium nitride (TiN) are deposited and heat-treated to form a barrier metal layer having titanium silicide (TiSi 2) at the bottom of the contact hole.

A method of forming a barrier metal layer of a conventional semiconductor device will be described with reference to FIGS. 1A to 1C.

Referring to FIG. 1A, a contact hole 13 is formed by etching selected regions of the interlayer insulating layer 12 formed on the silicon substrate 11. The titanium layer 14 is formed on the interlayer insulating layer 12 including the contact hole 13.

Referring to FIG. 1B, after the titanium nitride layer 15 is formed on the titanium layer 14, the titanium silicide layer 16 is formed on the silicon substrate 11 at the base of the contact hole 13 by heat treatment. ) Is formed.

In the above, the titanium nitride layer 15 has a poor step coverage, so that the overhang 18 is generated in the contact hole 13.

Referring to FIG. 1C, a tungsten layer 17 is formed on the titanium nitride layer 15. Since the tungsten layer 17 has a worse step coverage due to the overhang 18 of the titanium nitride layer 15, key holes 19, etc. are generated in the contact hole 13, thereby increasing the contact resistance.

Accordingly, an object of the present invention is to provide a method for forming a barrier metal layer of a semiconductor device capable of preventing overhang of a titanium nitride layer and lowering a contact resistance.

Barrier metal layer forming method of the present invention for achieving the above object comprises the steps of forming a titanium layer on the contact hole formed substrate; And nitriding the surface of the titanium layer to form a titanium nitride layer by heat treatment in a nitriding atmosphere, and then performing a heat treatment of the barrier metal layer.

1 (a) to 1 (c) are cross-sectional views of a device for explaining a method of forming a barrier metal layer of a conventional semiconductor device.

2 (a) to 2 (c) are cross-sectional views of a device for explaining a method of forming a barrier metal layer of a semiconductor device according to the present invention.

<Description of Signs of Major Parts of Drawings>

11 and 21: silicon substrates 12 and 22: interlayer insulating film

13 and 23: contact holes 14 and 24: titanium layer

15 and 25: titanium nitride layers 16 and 26: titanium silicide layers

17 and 27: tungsten layer 18: overhang

19: keyhole

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 (a) to 2 (c) are cross-sectional views of devices for explaining a method of forming a barrier metal layer of a semiconductor device according to the present invention.

Referring to FIG. 2A, a contact hole 23 is formed by etching a selected region of the interlayer insulating layer 22 formed on the silicon substrate 21. The titanium layer 24 is formed on the interlayer insulating layer 22 including the contact hole 23 by physical vapor deposition (PVD). The titanium layer 24 is formed to the thickness of the existing barrier metal layer (titanium layer / titanium nitride layer).

Referring to FIG. 2 (b), the titanium nitride layer having a thickness of 30 to 500 kPa is formed by nitriding the surface of the titanium layer 24 by performing heat treatment in an NH-based gas atmosphere such as NH ₃ gas and NH ₄ OH gas. 25), the barrier metal layer is heat-treated, thereby forming a barrier metal layer made of a titanium layer 2 and a titanium nitride layer 25, whereby the silicon substrate 21 at the base of the contact hole 23 is formed. Titanium silicide layer 26 is formed on the substrate.

Heat treatment for forming the titanium nitride layer 25 is carried out for 3 to 25 minutes at a temperature of 350 to 650 ℃ and a pressure of 0.2 to 10 Torr while flowing a NH series gas of 100 to 3500 sccm, the barrier metal layer heat treatment is 400 5 to 20 minutes at a temperature of to 700 ℃.

The heat treatment for forming the titanium nitride layer 25 and the heat treatment of the barrier metal layer may be performed at a temperature of 450 to 850 ° C. and a pressure of 0.2 to 10 Torr while flowing a NH series gas of 100 to 3500 sccm.

Referring to FIG. 2C, a tungsten layer 27 is formed on the titanium nitride layer 25.

As described above, the present invention forms a titanium nitride layer, which serves to prevent diffusion in the barrier metal layer, by performing heat treatment in a nitriding atmosphere, so that the tungsten layer is well buried in the contact hole part by preventing overhang and improving film quality. Can fulfill the role of the barrier metal layer, the contact resistance can be improved and the reliability of the device can be improved.

Claims (7)

Forming a titanium layer on a substrate on which contact holes are formed; And Treating the substrate on which the titanium layer is formed in a nitride atmosphere to nitride the surface of the titanium layer to form a titanium nitride layer, and then performing heat treatment on the barrier metal layer formed of the titanium layer and the titanium nitride layer. A method of forming a barrier metal layer of a semiconductor device, characterized in that the. The method of claim 1, The titanium layer is a barrier metal layer forming method of a semiconductor device, characterized in that formed by physical vapor deposition. The method of claim 1, The titanium nitride layer is a barrier metal layer forming method of a semiconductor device, characterized in that formed in a thickness of 30 to 500Å. The method of claim 1, The thermal treatment for forming the titanium nitride layer is performed for 3 to 25 minutes at a temperature of 350 to 650 ℃ and a pressure of 0.2 to 10 Torr while flowing a NH series gas of 100 to 3500 sccm Metal layer formation method. The method of claim 1, The barrier metal layer heat treatment is performed for 5 to 20 minutes at a temperature of 400 to 700 ℃ barrier metal layer forming method of a semiconductor device. The method of claim 1, The barrier metal layer heat treatment is performed at a temperature of 450 to 850 ° C. and a pressure of 0.2 to 10 Torr at a time while flowing an NH series gas of 100 to 3500 sccm. The method of claim 1, The nitride atmosphere is a barrier metal layer forming method of a semiconductor device, characterized in that the NH-based gas atmosphere, such as NH ₃ gas, NH ₄ OH gas.