KR19980033883A - Metal wiring formation method of semiconductor device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a metal wiring of a semiconductor device, wherein a further titanium film is laminated on a conventional titanium / reactive titanium nitride film, followed by heat treatment using a rapid heat treatment apparatus under ammonia gas or nitrogen atmosphere. Titanium film laminated on the layer is made of a titanium nitride film to compensate for the structural weakness of the existing reactive titanium film to prevent aluminum from diffusing into the junction region and reacting with silicon even during the subsequent heat treatment after the aluminum is deposited, Improve reliability

Description

Metal wiring formation method of a semiconductor device.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal wiring forming method of a semiconductor device, and more particularly, to a diffusion barrier film forming method having a laminated structure of a titanium film, a reactive titanium nitride film and a titanium nitride film as a diffusion barrier film.

In general, when the joining region of the silicon substrate and the aluminum film, which is a metal wiring film, are bonded, the aluminum film reacts with the silicon on the joining region due to a conventional subsequent thermal process, causing the aluminum ions and silicon to interdiffusion. Junction spiking occurs.

Therefore, at present, a diffusion preventing metal film is formed between the bonding region of the silicon substrate and the aluminum film so as to prevent the occurrence of the bonding failure phenomenon. Such a diffusion preventing metal film should not be reactive with aluminum and silicon, and should have excellent high temperature stability and diffusion suppression ability. Usually, TiW and TiN are widely used as a diffusion prevention metal film.

Conventionally, in the metal wiring method of a semiconductor device using a diffusion preventing metal layer, a contact hole is formed on an interlayer insulating film formed on a silicon substrate, a titanium film is deposited on the interlayer insulating film and the contact hole, and then a nitrogen gas atmosphere is used as a rapid heat treatment apparatus. A method of forming a titanium nitride on the upper surface of a titanium film by heat treatment has been proposed.

However, in the heat treatment process for forming the titanium nitride film, the upper part of the titanium film deposited on the junction region reacts with nitrogen to form titanium nitride, and the lower part of the titanium film reacts with silicon in the junction region to form silicide. At this time, since the silicide reaction occurs much faster than the formation rate of the titanium nitride film, there is a problem that it is difficult to control the thickness of the titanium nitride film.

To solve the above problems, a method of forming a diffusion preventing metal film of a conventional semiconductor device is shown in Figs. 1A to 1C.

Referring to FIG. 1A, an impurity is implanted into the silicon substrate 1 to form the junction region 2. The interlayer insulating film 3 is deposited on the silicon substrate 1, and the interlayer insulating film 3 is etched in a conventional manner so that the junction region 2 is exposed to form the contact hole 4.

Referring to FIG. 1B, a titanium film 5 and a titanium nitride film 6 are laminated with a diffusion preventing metal layer on the interlayer insulating film 3 and the junction region 2. The titanium nitride film 6 is usually formed by a reactive sputtering deposition method, which is a method of forming a titanium nitride film 6 by sputter deposition of a Ti target in an Ar + N ₂ atmosphere. This characteristic of the titanium nitride film 6 as a barrier metal is greatly dependent on the chemical equivalent ratio between Ti and N, and the case of 1: 1 is most preferably performed as a barrier metal.

Referring to FIG. 1C, an aluminum film 7 for metal wiring is deposited on the titanium nitride film 6, and then an aluminum film 7, a titanium nitride film 6, and a titanium film 5 are formed by a photolithography process. Etch to form metal wiring.

However, the metal wiring method using the reactive titanium nitride film as the conventional diffusion preventing metal layer is easy to control the thickness and high productivity, while aluminum ion is nitrided because the structure of the reactive sputtered titanium nitride film has a needle-like structure. By passing between the needle-like structures of the titanium film and diffusing to the junction region, there is a problem that can cause a junction failure phenomenon.

Therefore, the present invention forms a laminated structure of a titanium film, a reactive titanium nitride film and a titanium film as a diffusion preventing metal layer, and then rapidly heat-treats to form a titanium silicide in the contact portion with the junction region to compensate for the disadvantage of the diffusion preventing metal layer. An object of the present invention is to provide a method for forming a metal wiring of a semiconductor device capable of forming titanium nitride under the wiring layer to prevent diffusion of ions.

1A to 1C are diagrams for explaining a metal wiring formation method of a semiconductor device according to the prior art.

2A to 2C are diagrams for explaining a method for forming metal wirings in a semiconductor device according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

11 silicon substrate 12 junction region

13 interlayer insulating film 14 contact hole

15: first titanium film 16: reactive titanium nitride film

17: second titanium film 17 ': titanium nitride film

18: titanium silicide 19: aluminum metal film

The above object is to form a junction region by implanting impurities into a silicon substrate; Forming an interlayer insulating film on the silicon substrate; Forming a contact hole by etching the interlayer insulating layer by a photolithography process; Stacking a first titanium film, a reactive titanium nitride film, and a second titanium film on the interlayer insulating film and the contact hole; Heat-treating the laminated film; Depositing an aluminum metal on the titanium nitride film; And forming a metal wiring by etching the aluminum film and the laminated film by a photolithography process.

According to the present invention, after forming a laminated structure of a titanium film, a titanium nitride film and a titanium film as a diffusion preventing metal layer, the laminated film is heated with a rapid heat treatment apparatus at a predetermined temperature to titanium-silicide the titanium film formed on the junction region, thereby Even in the thermal process, it is possible to secure a diffusion preventing metal layer sufficient to prevent the diffusion of aluminum.

EXAMPLE

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

Referring to FIG. 2A, the junction region 12 is formed on the silicon substrate 11, the interlayer insulating layer 13 is deposited on the entire surface of the silicon substrate 11, and the interlayer insulating layer 13 is etched through a photolithography process. As a result, a contact hole 14 for connecting the metal wiring to be formed in the subsequent step and the junction region 12 is formed.

At this time, a natural oxide film is formed on the contact region 12 in the contact hole 14 during the formation of the contact hole, and dry cleaning is performed with NF ₃ to remove the natural oxide film.

Referring to FIG. 2B, the first titanium film 15, the reactive titanium nitride film 16, and the second titanium film 17 are sequentially stacked on the interlayer insulating film 13 and the contact hole 14 using sputtering equipment. do.

Referring to FIG. 2C, the semiconductor device formed by the above-described process may be heat treated at 600 ° C. to 700 ° C. with ammonia gas atmosphere or a rapid heat treatment apparatus of nitrogen gas atmosphere, or plasma treated with a plasma apparatus in an ammonia atmosphere. At this time, the portion of the first titanium film 15 under the reactive titanium nitride film 16 that is connected to the junction region 12 reacts with silicon in the junction region 12 to be deformed into titanium silicide 19 so as to have a contact resistance. The first titanium film 15 on the sidewall of the contact hole and the interlayer insulating film 13 is not deformed and is present as a titanium film.

The second titanium film 17 on the reactive titanium nitride film 16 is deformed into a thermal titanium nitride film 17 'by reacting with ammonia gas to form a thicker diffusion preventing metal layer. The thermal titanium nitride film 17 'serves to prevent aluminum from diffusing the titanium nitride film 16 into the bonding region 12 through the reactive titanium nitride film 16 having a needle-like structure.

Next, an aluminum metal film 19 is deposited on the titanium nitride film 17 ', and the aluminum metal film 19, the thermal titanium nitride film 17', the titanium nitride film 16, and the like are subjected to a photolithography process. The titanium silicide film 18 is etched to form metal wiring of the semiconductor device.

Meanwhile, a tungsten plug may be formed in the contact hole 14 before the aluminum metal film 19 is deposited. That is, after the tungsten film is deposited on the entire surface of the substrate to fill the contact hole, an etch back process or a chemical mechanical polishing process is performed until the titanium nitride film 17 'is exposed to form a tungsten plug, and the process is performed. It may also be carried out to form a metal wiring.

As described above, the metal wiring forming method of the semiconductor device according to the present invention is formed on the junction region by rapid thermal treatment of ammonia gas atmosphere after forming a laminated structure of a titanium film, a titanium nitride film and a titanium film as a diffusion preventing metal layer. The titanium film is titanium silicided to reduce contact resistance, and the second titanium film is transformed into a titanium nitride film to prevent diffusion of aluminum through the reactive titanium nitride film, thereby improving the characteristics and reliability of the semiconductor device.

Claims (14)

Implanting impurities into the silicon substrate to form a junction region; Forming an interlayer insulating film on the silicon substrate; Forming a contact hole by etching the interlayer insulating layer by a photolithography process; Stacking a first titanium film, a reactive titanium nitride film, and a second titanium film on the interlayer insulating film and the contact hole; Heat-treating the laminated film; Depositing an aluminum metal on the titanium nitride film; And forming a metal wiring by etching the aluminum film and the laminated film by a photolithography process. 2. The method of claim 1, further comprising removing the native oxide film formed on the surface of the junction region after the contact hole forming step and before the lamination film forming step. _{3. The} method for forming a metal wiring of a semiconductor device according to claim 2, wherein said natural oxide film is removed by dry cleaning with NF3. The method of claim 1, wherein the heat treatment is performed at a temperature of 600 ° C. to 700 ° C. with a rapid heat treatment apparatus of an ammonia gas atmosphere. The method of claim 1, wherein the heat treatment process is performed by a rapid heat treatment apparatus in a nitrogen atmosphere. The method of claim 1, wherein the heat treatment step is plasma-processed with a plasma apparatus in an ammonia gas atmosphere. 2. The method of claim 1, further comprising the step of forming a tungsten plug to fill the contact hole before the deposition of the aluminum metal. 8. The method of claim 7, wherein the tungsten plug is formed by depositing a tungsten thin film on the entire surface of the substrate and then performing an etch back process. 8. The method of claim 7, wherein the tungsten plug is formed by depositing a tungsten thin film on the entire surface of the substrate and then performing a chemical mechanical polishing process. A semiconductor substrate having a junction region formed therein, an interlayer insulating film having a contact hole over the junction region, a metal silicide formed in the junction region in the contact hole, a diffusion preventing metal layer formed on the sidewalls and the interlayer insulating film of the contact hole, and a metal silicide And a metal nitride film having a laminated structure formed on the diffusion preventing metal layer and a wiring metal film formed on the metal nitride film. The metal wiring of a semiconductor device according to claim 10, wherein said metal silicide is titanium silicide. The metal wiring of a semiconductor device according to claim 10, wherein said diffusion preventing metal layer is titanium. The metal wiring of the semiconductor device according to claim 10, wherein the metal nitride film has a laminated structure of a titanium nitride film and a reactive titanium nitride film. The metal wiring of a semiconductor device according to claim 10, wherein the wiring metal is aluminum.