KR20000027475A - Metal wire pattern for semiconductor device and method for forming the same - Google Patents

Abstract

PURPOSE: A metal wire pattern for a semiconductor device and a method for forming the same are provided to improve reliability of the metal wire pattern by covering a periphery of a wire pattern using a polluted nitride titanium presented on a surface of a titanium target. CONSTITUTION: A metal wire pattern for a semiconductor device includes first and second sacrifice layers. The semiconductor device includes a silicon substrate(100) on which a multi-layer having an insulating layer(102), a bonding layer(104), a diffusion barrier(106), a metal conductive layer(110), a metal bonding layer(112) and an anti-reflective layer(114), which are layered in this order. The first sacrifice layer is formed of a thin nitride titanium between the diffusion barrier(106) and the metal conductive layer. The second sacrifice layer is also formed of a thin nitride titanium deposited on a top and side of the multiple-layer. The first and second sacrifice layers are formed of an intermetallic compound(118) enclosing the metal conductive layer together with the metal bonding layer through a heat-treat process.

Description

Metal wiring for semiconductor devices and its manufacturing method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to metal wirings for use in semiconductor devices, and more particularly, to metal wirings for semiconductor devices suitable for suppressing a decrease in wiring reliability due to electromigration and a method of manufacturing the same.

In recent years, the area of semiconductor devices has been gradually reduced as the semiconductor devices have increased in capacity and density and, as a result, metal wirings and their line widths in semiconductor devices have been reduced.

At this time, the resistance of the metal wiring increases as the length of the lead wire becomes longer and the line width of the lead wire becomes thin, and the line width of the metal wire decreases as the device's capacity and high integration increase, resulting in the resistance and current density of the metal wire. By increasing the number, the electromigration phenomenon occurs, causing a problem such as disconnection of the metal wiring. That is, not only the reliability of the metal wiring is lowered, but also it is a great factor for reducing the production yield of the semiconductor device.

Therefore, as part of solving the above-described problems, various methods of forming metal wirings with a composite layer including a diffusion barrier layer made of titanium nitride have been proposed.

3 is a cross-sectional view showing an example of a structure of a metal wiring for a semiconductor device formed by forming a metal wiring as a composite layer according to a conventional method, wherein the conventional metal wiring is formed of an insulating layer 202 stacked on a silicon substrate 200. The bonding layer 204, the diffusion barrier layer 206, the metal conductive layer 208, the metal bonding layer 210, and the anti-reflection film 212 are sequentially stacked on top.

Referring to FIG. 3A, the upper portion of the insulating layer 202 stacked on the silicon substrate 200 may be formed of titanium (Ti) through physical vapor deposition (PVD) or chemical vapor deposition (CVD) by sputtering using a titanium target. The junction layer 204 of about 100-500 mW and the diffusion barrier layer 206 of about 300-1000 mW of titanium nitride (TiN) are sequentially deposited. At this time, the formation of the bonding layer 204 and the diffusion barrier layer 206 by sputtering is performed in the same chamber using a titanium target in consideration of manufacturing cost, manufacturing efficiency, and the like.

Next, a predetermined thickness that targets a metal having good electrical conductivity, for example, a metal such as aluminum (Al) or copper (Cu), through chemical vapor deposition (CVD) by sputtering or the like on top of the diffusion barrier layer 206. As much as for example, several thousand micrometers of vapor deposition, the metal conductive layer 208 is formed.

Subsequently, a metal bonding layer 210 made of titanium and titanium nitride on top of the metal conductive layer 208 are performed by performing the same process in the chamber as the process of forming the bonding layer 204 and the diffusion barrier layer 206 described above. The anti-reflection film 212 is sequentially deposited by a predetermined thickness.

Through the process described above, the bonding layer 204, the diffusion barrier layer 206, the metal conductive layer 208, the metal bonding layer 210, and the anti-reflection film 212 are sequentially stacked on the insulating layer 202. In this state, when the heat treatment process or the subsequent heat process is performed, as shown in FIG. 3B, the bonding layer 204 and the metal are reacted by the reaction of aluminum or copper and titanium and the reaction between aluminum or copper and titanium nitride. An intermetallic compound layer 214 is formed between the conductive layers 208 and between the metal conductive layer 208 and the antireflection film 212, respectively.

Accordingly, in the conventional metal wiring method as described above, the formation structure of the metal wiring is improved through the formation of the above-described intermetallic compound layer, and the intermetallic compound layer is shunted when the intermetallic compound layer is defective due to the formation of voids in the metal wiring. By functioning as a layer, the reliability of metal wiring is improved.

However, in the conventional metal wiring as described above, the formation of the thick intermetallic compound layer by the reaction between the thick titanium film or the titanium nitride film and the metal conductive layer has a large resistance heat due to the increase in the resistance of the metal wire and the increase in the current density. By this problem, the fundamental problem that leads to a decrease in wiring reliability due to electromigration (a decrease in wiring reliability due to diffusion through grain boundaries in electromigration) cannot be avoided.

In the conventional metal wiring structure, the exposed portions 208a and 208b on the side surfaces of the metal conductive layer 208 provide an interface diffusion path in the electromigration, which is a factor of lowering the reliability of the metal wiring.

Furthermore, in the conventional metal wire fabrication process, when the bonding layer 204 and the diffusion barrier layer 206 are formed by sputtering, they are performed in the same chamber using a titanium target, in which case a diffusion bonding layer made of titanium is used. When depositing 204 and metal bonding layer 210, the surface of the titanium target is contaminated with titanium nitride of a predetermined thickness (eg, about 10-100 GPa).

Thus, when performing a titanium deposition process on a wafer of the next process using such a titanium-contaminated titanium target, pure titanium is not initially deposited but a thin layer of titanium nitride is deposited, followed by pure titanium deposition, e.g. For example, assuming that about 100 microseconds of titanium nitride is contaminated with nitrogen on the surface of a titanium target, and that the target thickness of the titanium layer to be deposited on the wafer is about 500 microns, 100 micros of contaminated titanium nitride is deposited first and then the remaining 400 microns of titanium nitride is deposited. Pure titanium will be deposited. As a result, the contaminated titanium nitride layer greatly increases the contact resistance between titanium and silicon, which is a great factor that significantly lowers the contact efficiency between silicon and titanium.

Therefore, in the conventional method of manufacturing metal wiring, in order to solve the problems described above, a method of removing a contaminated titanium nitride by removing a contaminated titanium nitride on the shutter before installing a separate shutter on the wafer and performing the titanium deposition process. I use it.

However, as described above, the conventional method of removing the contaminated titanium nitride from the titanium target by using the shutter not only has a complicated structure in which a separate shutter is installed on the wafer but also has to separately perform the process of removing the contaminated titanium nitride. As a result, there is still a problem that acts as a factor that lowers the manufacturing cost and efficiency of the semiconductor device.

Accordingly, the present invention is to solve the above problems of the prior art, by using a contaminated titanium nitride on the surface of the titanium target to cover the metal wiring circumference, to improve the wiring reliability of the semiconductor device metal wiring The purpose is to provide.

Another object of the present invention is to form a thin intermetallic compound layer around the metal wiring using contaminated titanium nitride on the surface of the titanium target, thereby suppressing diffusion and interfacial diffusion through grain boundaries in electromigration to prevent degradation of wiring reliability. The present invention provides a method for manufacturing a metal wiring for a semiconductor device.

SUMMARY OF THE INVENTION The present invention has a semiconductor device having a composite layer structure in which a bonding layer, a diffusion barrier layer, a metal conductive layer, a metal bonding layer, and an antireflection film are sequentially stacked on top of an insulating layer on a silicon substrate. A metal wiring, comprising: a first sacrificial layer of thin titanium nitride formed between the diffusion barrier layer and the metal conductive layer; And a second sacrificial layer of thin titanium nitride formed over the upper and side surfaces of the composite layer, wherein the first and second sacrificial layers, together with the metal bonding layer, are subjected to a heat treatment process through the metal conductive layer. The metal wiring for semiconductor devices characterized by being formed of the intermetallic compound layer surrounding the periphery.

According to another aspect of the present invention, there is provided a method of manufacturing a metal wiring composed of a composite layer including a metal conductive layer on top of an insulating layer on a silicon substrate, wherein the junction of titanium is formed on the top of the insulating layer. Sequentially depositing a layer and a diffusion barrier layer of titanium nitride; Depositing a first sacrificial layer of titanium nitride of a thin film contaminated with nitrogen on the diffusion barrier layer; Depositing a metal conductive layer on top of the first sacrificial layer; Sequentially depositing a metal bonding layer made of titanium and an antireflection film made of titanium nitride on the metal conductive layer, and patterning and etching the deposited composite layer to form metal wirings; Depositing a second sacrificial layer of contaminated thin film of titanium nitride over the exposed top surface of the insulating film and the top and side surfaces of the composite layer; Forming an intermetallic compound layer of a thin film surrounding the lower, upper, and side surfaces of the metal conductive layer through a heat treatment process; And removing the second sacrificial layer formed on the exposed insulating layer and on the composite layer.

1 is a cross-sectional view of a metal wiring for a semiconductor device according to a preferred embodiment of the present invention;

2 is a process diagram sequentially showing each process of manufacturing metal wiring for a semiconductor device according to a preferred embodiment of the present invention;

3 is a cross-sectional view showing a structure of a gold wire for a semiconductor device manufactured according to a conventional method.

<Description of the code | symbol about the principal part of drawing>

100 silicon substrate 102 insulating layer

104 bonding layer 106 diffusion barrier layer

110: metal conductive layer 112: metal bonding layer

114: antireflection film 116: diffusion barrier layer

118: intermetallic compound layer

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

First, the technical idea of the present invention is to cover the diffusion path through the side and the increase of the current density caused by the formation of the excess intermetallic compound layer by covering the circumference with a thin intermetallic compound layer so as to cap the metal wiring. Blocking to prevent degradation of the wiring reliability due to electromigration, and also to form a part of the intermetallic compound layer using contaminated titanium nitride on the surface of the titanium target, thereby contaminating nitride using the shutter as in the conventional method. It is to omit the process of removing titanium to increase the manufacturing cost and efficiency of the semiconductor device.

1 is a cross-sectional view of a metal wiring for a semiconductor device according to a preferred embodiment of the present invention.

As shown in the same figure, the metal wiring for semiconductor devices of the present invention includes an insulating layer 102, a bonding layer 104 made of titanium, and a diffusion barrier layer made of titanium nitride on the silicon substrate 100. ), The intermetallic compound layer 118, the metal conductive layer 110 made of aluminum or copper, the intermetallic compound layer 118, and the antireflection film 114 made of titanium nitride are sequentially stacked. In addition, the metal conductive layer 110 made of aluminum (Al) or copper (Cu) has a shape in which the periphery thereof is capped by the intermetallic compound layer 118, that is, the lower, upper and side portions of the metal conductive layer 110 are formed. It is covered with an intermetallic compound layer 118.

At this time, the intermetallic compound layer 118 formed on the upper side of the metal conductive layer 110 is a relatively thick intermetallic compound layer formed by the reaction between aluminum or copper and titanium having a thickness of approximately 100 to 500 kPa during the heat treatment process. The intermetallic compound layer 118 formed on the lower side and side portions of the conductive layer 110 is a relatively thin intermetallic compound layer formed by the reaction between aluminum or copper and titanium nitride having a thickness of approximately 10-100 kPa during the heat treatment process.

That is, in the intermetallic compound layer surrounding the metal conductive layer 110, the intermetallic compound formed on the lower side and the side portion is formed on the surface of the titanium target when titanium nitride is deposited on the titanium through a sputtering process using a titanium target. It is produced by a heat treatment reaction between titanium nitride and aluminum or copper which is deposited using 10 to 100 오염 contaminated titanium nitride, and in the present invention, such a thin intermetallic compound is formed on the lower and side portions of the metal conductive layer 110. By forming in, it is possible to suppress an increase in current density (increase in metal resistance) due to excessive formation of an intermetallic compound layer, and to block a diffusion path through the side surface, thereby effectively preventing a decrease in wiring reliability due to electromigration.

Here, a thin titanium nitride of about 10 to 100 microns used to form the intermetallic compound layer on the lower side of the metal conductive layer 110 is a diffusion barrier layer of titanium nitride on top of the bonding layer 104 made of titanium. A film formed by sputtering a contaminated titanium nitride (i.e., titanium contaminated with nitrogen) formed on the surface of a titanium target (not shown) to form a thickness of approximately 10 to 100 microseconds. A thin titanium nitride of about 10 to 100 microns used to form an intermetallic compound layer on the side of the side portion of 110 is an antireflection film 114 of titanium nitride on top of the metal bonding layer of titanium (112 in FIG. 2). Is formed by sputtering contaminated titanium nitride (i.e., titanium contaminated with nitrogen) formed on the surface of the titanium target (not shown) to form a thickness of approximately 10 to 100 microns.

Therefore, in the metal wiring according to the present invention, a thin intermetallic compound layer is formed to effectively remove contaminated thin titanium nitride on the surface of the titanium target and simultaneously cap the circumference of the metal conductive layer using the thin titanium nitride. By blocking the diffusion path due to the increase of the current density and the side exposure of the metal wiring, it is possible to improve the wiring reliability by the electromigration as well as to improve the process efficiency.

Next, a method of forming the metal wiring of the present invention having the structure as described above will be described in detail with reference to FIG.

Referring to FIG. 2A, titanium (Ti) may be formed by physical vapor deposition (PVD) or chemical vapor deposition (CVD) by reactive sputtering using a titanium target on the insulating layer 102 stacked on the silicon substrate 100. A deposition layer 104 of about 100 to 500 mW and a diffusion barrier layer 106 of about 300 to 1000 mW of titanium nitride (TiN) are sequentially deposited. At this time, the formation of the bonding layer 104 and the diffusion barrier layer 106 by reactive sputtering is performed in an argon gas atmosphere and an argon and nitrogen gas atmosphere in the same chamber using a titanium target (not shown).

On the other hand, when the deposition process of the diffusion barrier layer 106 is completed, the surface of the titanium target is contaminated with nitrogen of about 10-100 kPa, and sputtering with argon gas only without nitrogen gas is performed, thereby performing approximately 10-100 kPa. A first sacrificial layer 108 of thin titanium nitride is deposited on top of the diffusion barrier layer 106. Thus, titanium nitride on the contaminated titanium target surface is completely removed during the deposition process of the diffusion barrier layer 106.

Next, as shown in FIG. 2B, a metal having good electrical conductivity, such as aluminum (Al) or copper (Cu), through chemical vapor deposition (CVD) by sputtering or the like on top of the first sacrificial layer 108. The metal conductive layer 110 is formed by depositing a metal such as a predetermined thickness (for example, about several thousand micrometers).

Subsequently, by performing the same process in the same chamber as the above-described process of forming the bonding layer 104 and the diffusion barrier layer 106, as shown in FIG. 2C, titanium on top of the metal conductive layer 110, The metal bonding layer 112 and the anti-reflection film 114 made of titanium nitride are sequentially deposited to a predetermined thickness, and then a dry etching process is performed to form a metal wiring made of a composite layer. That is, in FIG. 2A to FIG. 2C, the composite layers are sequentially formed in the form of the patterned metal wirings, but substantially after lamination of the composite layers is completed (that is, after the antireflection film 114 is deposited). The dry etching process is performed to form patterned metal lines as shown in FIG. 2C.

On the other hand, when the patterned metal wiring with the composite layer is completed as mentioned above, the surface of the titanium target is contaminated with nitrogen at about 10-100 kPa, which is not filled with nitrogen gas as shown in FIG. 2D. Sputtering only with argon gas in the state to extend the second sacrificial layer 116 of thin titanium nitride of approximately 10 to 100 microns over the exposed side of the insulating layer 102 and the side and top of the composite wiring. Deposit. Therefore, titanium nitride on the surface of the contaminated titanium target during the deposition process of the antireflection film 114 is removed.

Then, a heat treatment process is performed to form an intermetallic compound layer 118 that wraps around the metal conductive layer 110, that is, the lower, upper and side portions of the metal conductive layer 110, as shown in FIG. 2E. An intermetallic compound layer 118 is formed surrounding the metal.

Here, the intermetallic compound layer 118 formed on the upper side of the metal conductive layer 110 is a relatively thick intermetallic compound layer formed by reaction between aluminum or copper and titanium having a thickness of about 100 to 500 kPa in the heat treatment process, The intermetallic compound layer 118 formed on the lower side and side portions of the metal conductive layer 110 is a relatively thin intermetallic compound layer formed by the reaction between aluminum or copper and thin titanium nitride having a thickness of approximately 10-100 kPa during the heat treatment process. to be.

On the other hand, when the metal conductive layer 110 is aluminum, the heat treatment step of forming the intermetallic compound layer 118 is approximately 30 at a temperature of approximately 350-450 캜 in a heat treatment furnace of hydrogen (or nitrogen, nitrogen / hydrogen) atmosphere. It can be carried out by maintaining about 60 or 10-30 seconds in the temperature range of approximately 350-450 ℃ using Rapid Thermal Annealing (RTA).

On the other hand, when the metal conductive layer 110 is copper, the heat treatment process for forming the intermetallic compound layer 118 has a high melting point of copper compared to aluminum, so that the aluminum in the temperature range of about 600 to 700 ℃, The same can be done with.

Next, through the anisotropic etching (RIE) process, part of the unnecessary titanium nitride is removed, that is, the titanium nitride and the anti-reflection film 114 on the exposed insulating layer 102 in the second sacrificial film 116 of thin titanium nitride. By removing the titanium nitride on the phase, the metal wiring for the semiconductor device according to the present invention having the laminated structure as shown in FIG. 2 f is completed, that is, the thin intermetallic compound layer 118 surrounds the metal conductive layer 110. The metal wiring of the laminated structure which has a is completed.

As described above, according to the present invention, a thin intermetallic compound layer is coated around the metal wire to cap the metal wire, thereby suppressing an increase in current density due to excessive formation of the intermetallic compound layer and in terms of the metal wire. By blocking the diffusion path, the wiring reliability can be improved by increasing the resistance to electromigration.

In addition, according to the method of manufacturing the metal wiring of the present invention, since it does not require periodic cleaning or installation of a shutter due to contamination of the titanium target, it is possible to reduce manufacturing costs and to prevent the formation of fine particles due to contamination of the titanium target. It can improve manufacturing efficiency.

Claims (10)

In a metal wiring for a semiconductor device having a composite layer structure in which a bonding layer, a diffusion barrier layer, a metal conductive layer, a metal bonding layer, and an antireflection film are sequentially stacked on top of an insulating layer on a silicon substrate, The metal wiring is: A first sacrificial layer of thin titanium nitride formed between the diffusion barrier layer and the metal conductive layer; And A second sacrificial layer of thin titanium nitride formed over the top and side surfaces of the composite layer, And the first and second sacrificial layers are formed of an intermetallic compound layer surrounding the circumference of the metal conductive layer through a heat treatment process together with the metal bonding layer. The method of claim 1, wherein the first and second sacrificial layers are formed by sputtering contaminated titanium nitride formed on the surface of the titanium target when the diffusion barrier layer and the anti-reflection film are respectively deposited. Metal wiring for semiconductor devices. The metal wiring for a semiconductor device according to claim 1 or 2, wherein the first and second sacrificial layers each have a thickness range of 10 to 100 GPa. In the method for manufacturing a metal wiring of a composite layer comprising a metal conductive layer on top of an insulating layer on a silicon substrate, Sequentially depositing a junction layer made of titanium and a diffusion barrier layer made of titanium nitride on the insulating layer; Depositing a first sacrificial layer of titanium nitride of a thin film contaminated with nitrogen on the diffusion barrier layer; Depositing a metal conductive layer on top of the first sacrificial layer; Sequentially depositing a metal bonding layer made of titanium and an antireflection film made of titanium nitride on the metal conductive layer, and patterning and etching the deposited composite layer to form metal wirings; Depositing a second sacrificial layer of contaminated thin film of titanium nitride over the exposed top surface of the insulating film and the top and side surfaces of the composite layer; Forming an intermetallic compound layer of a thin film surrounding the lower, upper, and side surfaces of the metal conductive layer through a heat treatment process; And And removing the second sacrificial layer formed on the exposed insulating layer and on the composite layer. The method of manufacturing a metal wiring for a semiconductor device according to claim 4, wherein the deposition of the metal bonding layer and the antireflection film is performed sequentially in the same chamber using a titanium target. The method of claim 4, wherein when the metal conductive layer is aluminum, the heat treatment process for forming the intermetallic compound layer is performed in a temperature range of 350 to 450 ° C. through a heat treatment furnace in a hydrogen, nitrogen, or nitrogen / hydrogen atmosphere. The metal wiring manufacturing method for semiconductor devices characterized by the above-mentioned. The method of claim 4, wherein when the metal conductive layer is aluminum, the heat treatment process for forming the intermetallic compound layer is performed at a temperature range of 350 to 450 ° C. using rapid thermal annealing (RTA). The metal wiring manufacturing method for semiconductor devices. The method of claim 4, wherein when the metal conductive layer is copper, the heat treatment process for forming the intermetallic compound layer is performed at a temperature range of 600 to 700 ° C. through a heat treatment furnace in a hydrogen, nitrogen, or nitrogen / hydrogen atmosphere. The metal wiring manufacturing method for semiconductor devices characterized by the above-mentioned. The method of claim 4, wherein when the metal conductive layer is copper, the heat treatment process for forming the intermetallic compound layer is performed at a temperature range of 600 to 700 ° C. using rapid thermal annealing (RTA). The metal wiring manufacturing method for semiconductor devices. The method of claim 4, wherein the second sacrificial layer formed on the exposed insulating layer and on the composite layer is removed by anisotropic etching.