KR100268804B1 - Metal wiring formation method of semiconductor device - Google Patents

Abstract

PURPOSE: A method for forming a metal line of a semiconductor device is provided to form a Ti/TiN metal film as a diffusion barrier by using automatic layer epitaxy chemical vapor deposition method. CONSTITUTION: A diffusion barrier of a stacked structure of Ti/TiN formed on a lower portion of a metal line is formed by an automatic layer epitaxy chemical vapor deposition method. A TiCl4 gas is used as a source gas. An H2 gas and an ammonia gas are used as reaction gases. The stacked structure of Ti/TiN is formed by performing an in-situ process in one reaction furnace. The generated byproducts are purged by using an argon gas when forming the stacked structure of Ti/TiN.

Description

Metal wiring formation method of semiconductor device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming metal wirings in semiconductor devices, and more particularly, to a technique of forming a Ti / TiN metal thin film as a diffusion barrier on a semiconductor substrate by ALE CVD (atomic layer epitaxy chemical vapor deposition) method. .

In general, the wiring of a semiconductor device for electrically connecting between devices or between an element and an external circuit is made through a subsequent process by filling a predetermined contact hole and via hole for wiring with a wiring material and forming a wiring layer. Metal wiring is used where resistance is required.

The metal wiring is a physical vapor deposition (Physical) of the diffusion barrier layer of the Ti / TiN laminated structure, and the aluminum alloy containing a small amount of silicon or copper in the aluminum (Al) or both silicon and copper with low resistivity and excellent workability Vapor Deposition, hereinafter referred to as PVD) method. Of course, the Ti / TiN laminated structure may be formed by chemical vapor deposition (hereinafter, referred to as CVD).

However, the Ti / TiN laminates are formed in different reactors, so losses are expected in terms of productivity and throughput. After the Ti deposition, the film quality of the Ti thin film is expected to change when the process atmosphere for forming TiN is changed.

As described above, the metal wiring formation method of the semiconductor device according to the prior art may cause degradation of characteristics such as productivity, film quality and throughput during the formation process of the Ti / TiN laminate structure, which is a diffusion barrier film. And lowering reliability and lowering yield and productivity of the semiconductor device.

Therefore, in order to solve the above problems of the prior art, a method for forming metal wirings of a semiconductor device of a semiconductor device, which can easily form a Ti / TiN stacked structure in one reactor using the ALE CVD method. The purpose is to provide.

In order to achieve the above object, a metal wiring forming method of a semiconductor device according to the present invention,

As a method of forming a metal wiring in a semiconductor device in which a diffusion barrier layer of a Ti / TiN layer structure formed under the metal wiring is formed by the ALE CVD method in the metal wiring formation process of the semiconductor device,

TiCl ₄ gas is fixed with a source gas, and H ₂ and ammonia gas, respectively, are sequentially flowed and a Ti / TiN lamination structure is formed in an in-situ process in one reactor.

And purging the by-products generated during the Ti / TiN laminate structure forming process with argon gas.

Meanwhile, in order to achieve the above object, the winry of the present invention uses TiCl ₄ as a precursor during Ti / TiN deposition, and the reactor is H ₂ gas for Ti and NH _{3 for} TiN. A gas or N ₂ / H ₂ mixed gas is used, and a purge gas is argon (Ar) gas to form a Ti / TiN laminated structure by ALE CVD, but in-situ By depositing sequentially in the reactor of the to improve the film quality.

For reference, the ALE CVD is a method of forming a cyclic-monolayer by supplying a source gas, a purge gas, and a reactor with a cyclic pulse, and adsorption on the surface of the semiconductor substrate. By using the principle of desorption (desorption) can be adjusted to a very thin film thickness of about 10 Å, it is possible to precisely control the composition of the multi-element thin film and to suppress the growth and diffusion of thin film defects.

Hereinafter, although not shown, the present invention will be described in detail.

First, TiCl ₄ source is supplied at a limited flow rate of 10 to 1000 sccm for 0.1 to 60 seconds, and TiCl ₄ is adsorbed onto the substrate having a temperature of about 200 to 700 ° C. Then, argon gas is continuously flowed by 10 to 1000 sccm. A source purge is performed for 0.1 to 120 seconds.

Thereafter, the H ₂ reaction gas was flowed for 10 to 1000 sccm for 0.1 to 60 seconds to adsorb H ₂ onto TiCl ₄ already adsorbed on the semiconductor substrate to cause a reaction as shown in the following formula 1 to form a Ti monolayer ( monolayer).

TiCl ₄ (g) + 2H ₂ (g) = Ti (s) + 4HCl (g) -------- Formula 1

At this time, the total pressure in the reactor maintains about 0.1 to 5 Torr. Thereafter, argon gas is flowed to purge the reactor, by-products and HCl.

The cycle as described above is repeated 5 to 2000 times to form a Ti thickness of about 10 to 500 kPa.

Then, a TiN thin film is deposited on the Ti thin film in this manner, but replaced with ammonia gas (NH ₃ ) instead of H ₂ gas. In this case, TiCl ₄ is again adsorbed on the surface of the already formed Ti thin film, and the ammonia gas adsorbed on the upper portion reacts as in the following formula 2 to form a TiN monolayer. The same cycle is repeated 5 to 2000 times in order to form the TiN thin film with a thickness of about 10 to 600 kPa.

6TiCl ₄ (g) + 8NH ₃ (g) = 6TiN (s) + 24HCl (g) + 8N ₂ (g)-Formula 2

Then, the reactants caused by the reaction of the above formulas 1 and 2, ie by-products HCl, N ₂ are purged.

Here, the TiN thin film forming process may share a gas pipe used in the Ti thin film forming process in order to flow ammonia gas, or may use a separate gas pipe.

In the case of using the separate gas pipe, the reaction gas may be more easily controlled by continuously flowing the H ₂ gas used for depositing the Ti thin film and simultaneously adjusting the ammonia gas flow rate. The reaction principle at this time is as shown in the following third equation.

2TiCl ₄ (g) + 2NH ₃ (g) + H ₂ (g) = 2TiN (s) + 8HCl (g)-Formula 3

On the other hand, the injection method of the source and the reaction gases in the reactor, as in the conventional ALE CVD method flows in parallel to the direction in which the semiconductor substrate is placed. In this case, although there is an advantage of allowing adsorption of gases on the substrate in a short time, there is a problem that the thickness of the thin film is not uniformly deposited because the gases flow only in one direction of the substrate, but the semiconductor substrate is 10 to 500 rpm during thin film deposition. It rotates at a speed that allows the same amount of source and reactant gas to be adsorbed onto the substrate for the same amount of time in all directions of the substrate.

As described above, the metal wiring forming method of the semiconductor device according to the present invention has an effect of easily forming a Ti / TiN laminated structure having a stable film quality to improve the characteristics and reliability of the semiconductor device.

Claims (7)

As a method of forming a metal wiring of a semiconductor device in which a diffusion barrier of a Ti / TiN stacked structure formed under the metal wiring is formed by the ALE CVD method in the process of forming a metal wiring of a semiconductor device, TiCl ₄ gas is fixed to a source gas, H ₂ and ammonia gas, respectively, are sequentially flowed, forming a Ti / TiN layer structure in an in-situ process in one reactor, and purging the by-products generated during the Ti / TiN layer formation process with argon gas. A metal wiring forming method of a semiconductor device comprising the step of. The Ti thin film deposition process according to claim 1, wherein the Ti thin film deposition process maintains the pressure in the reactor at 0.1 to 5 Torr, and flows the H ₂ reaction gas for 10 to 1000 sccm for 0.1 to 60 seconds to adsorb H ₂ onto the TiCl ₄ adsorbed onto the semiconductor substrate. Next, a cycle for purging the reactor gas and by-products with argon gas (cycle) is repeated 5 to 200 times to form a metal wiring of the semiconductor device, characterized in that to form a thickness of 10 ~ 500Å. The TiN thin film deposition process according to claim 1, wherein the TiN thin film deposition process is performed by adsorbing TiCl ₄ on the surface of the Ti thin film, adsorbing ammonia gas on the top thereof, and repeating the cycle 5 to 2000 times to form a thickness of 10 to 600 μs. A metal wiring forming method of a semiconductor device, characterized in that. The TiCl ₄ gas is a precursor of the Ti thin film and the TiN thin film, and has a flow rate of 10 to 1000 sccm for 0.1 to 60 seconds before forming the Ti thin film and the TiN thin film. Metal wiring forming method of a semiconductor device, characterized in that the giving. The method of claim 1, wherein the purge step using argon gas is performed at a flow rate of 10 to 1000 sccm for 0.1 to 120 seconds. The method of claim 1, wherein the ALE CVD is performed by using a temperature of a semiconductor substrate at 200 ° C. to 700 ° C. and a pressure in the reactor at 0.5˜2 Torr. The method according to claim 1 or 6, wherein the ALE CVD is performed by rotating the semiconductor substrate at 10 to 500 rpm.