KR20060016269A - Method of forming a metal silicide layer and method of forming a metal wiring of a semiconductor device using the same - Google Patents

Abstract

A method of forming a metal silicide film of a semiconductor device and a method of forming a metal wiring using the same are disclosed. A metal film having a uniform thickness is formed on the insulating film having a contact hole exposing the surface of the substrate. The surface of the metal film is modified with a metal nitride film by performing a plasma nitridation process on the metal film. The substrate is thermally treated to react the metal film on the bottom surface of the contact hole with the substrate to form a metal silicide film. A contact plug and a bit line are formed to fill the contact hole in which the metal silicide layer is formed. When forming the metal wiring to which the method described above is applied, the bit line metal wiring can be easily formed by using the metal silicide layer to improve electrical characteristics and shorten manufacturing time.

Description

Method of forming a metal silicide layer and method of forming a metal wiring of a semiconductor device using the same}

1 is a process chart showing a method of forming a cobalt silicide film in forming a conventional bit line electrode.

2 to 6 are cross-sectional views illustrating a method of forming a cobalt silicide layer and a bit line according to an exemplary embodiment of the present invention.

7 to 9 are cross-sectional views illustrating a method of forming a cobalt silicide layer and a bit line according to another exemplary embodiment of the present invention.

10 to 11 are cross-sectional views illustrating a method of forming a cobalt silicide layer and a bit line according to still another exemplary embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

100 semiconductor substrate 110 gate electrode

120: source / drain 130: interlayer insulating film pattern

140: contact hole 150: metal film

160 metal nitride film 170 metal silicide film

180: contact plug 182: bit line

The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a metal silicide film applied to a bit line forming process electrically connected to a substrate and a method of forming a metal wiring using the same.

In recent years, with the rapid spread of information media such as computers, semiconductor devices are also rapidly developing. In terms of its function, the semiconductor device is required to operate at a high speed and to have a large storage capacity. In response to these demands, the manufacturing technology of the semiconductor device has been developed to improve the degree of integration, reliability, and response speed. Accordingly, the demand for processing technology such as a deposition process for forming a film is also increasing as a major technology for improving the integration degree of the semiconductor device.

Recently, since the semiconductor device has a design rule of 0.11 μm or less, as the size of the pattern formed on the chip becomes smaller and the spacing between the patterns becomes smaller, the ultrafine pattern formed in multiple layers This is required.

By forming the pattern in multiple layers as described above, a contact is required to electrically connect the interlayer patterns. As the degree of integration of the device increases, the contact window size connecting the interlayer patterns decreases. Therefore, when poly-silicon or the like, which has been previously used, is formed at the site where the contact is formed, high contact resistance or sheet resistance is difficult to expect high-speed operation and power consumption problems occur.

For the above reason, a method of forming a metal silicide film, which is a compound of metal and silicon, is applied to active regions in which a contact is formed, that is, a source and a drain region.

The process of forming the silicide film is called a silicidation process. US Pat. No. 6,100,145 (Kepler et al.) Discloses a silicidation process.

In the silicidation process, when a metal material such as titanium (Ti), nickel (Ni), or cobalt (Co) is deposited and heat treated, when a silicon element is present in the underlying film, the metal and the silicon element react to form titanium. It is a process for forming a silicide (titanium silicide), nickel silicide (nikel silicide) or cobalt silicide (cobalt silicide).

1 is a process chart showing a method of forming a cobalt silicide film in forming a conventional bit line.

Referring to FIG. 1, an insulating film is formed on the silicon substrate on which the gate electrode and the source / drain regions are formed to have a thickness of about 2000 μs. Subsequently, the insulating film is patterned to form an insulating film pattern including a contact hole exposing a portion of the source / drain region (step S10).

Subsequently, a cobalt film having a thickness of about 50 GPa and a titanium film or a titanium nitride layer TiN having a thickness of about 50 GPa to 100 GPa are formed on the contact hole and the insulating layer pattern as a capping layer. It is formed sequentially (steps S20 and S30).

Subsequently, after transferring the substrate on which the capping film is formed into the heat treatment chamber, the substrate is subjected to a first heat treatment process at a temperature of about 500 ° C. (step S40). Here, when the first heat treatment process is performed, a silicidation process is performed in which cobalt silicide is formed by chemically reacting silicon of the substrate and cobalt of the capping layer.

Subsequently, a cobalt silicide film is formed on the bottom of the contact hole by a silicidation process, and then the capping film and the cobalt film not reacted with the silicidation process are removed by a wet etch process (step S50).

After transferring the substrate subjected to the etching process into the heat treatment chamber, the substrate is subjected to a second heat treatment process at a temperature of about 850 ° C. to reduce the contact resistance of the bit line metal wiring ohmic contact (ohmic) contact) a film is formed (step S60).

In the above-described conventional technique, when the capping film is formed before the first heat treatment process, the substrate is exposed to the air to form a natural oxide film on the cobalt film, and the natural oxide film is formed after the contact resistance of the bit line metal wiring. It acts as a factor to increase. Therefore, there is a need for a new capping film deposition process that prevents natural oxide films on cobalt films.

However, there are two problems when performing the conventional capping film deposition process. First, the throughput of the semiconductor device manufacturing process is reduced by adding a capping film deposition process.

Secondly, the cobalt and capping film deposition processes are typically performed in different chambers, so the pressure and gas atmosphere acting on the substrate is changed during transfer of the substrate between the chambers. Therefore, a cobalt oxide film may be formed on the surface of the cobalt film during the transfer of the substrate or the atmosphere before the capping film is deposited. The cobalt oxide layer may act as a factor of increasing contact resistance.

Accordingly, an object of the present invention is to provide a method of forming a cobalt silicide film having excellent electrical characteristics in a bit line forming process of a semiconductor device through a simple process.

Another object of the present invention is to provide a method for forming a metal wiring in a semiconductor device using the method for forming a cobalt silicide film described above.

Metal silicide film forming method according to an aspect of the present invention for achieving the above object, the step of forming a metal film having a uniform thickness on the insulating film having a contact hole for exposing the surface of the substrate, plasma on the metal film Performing a nitriding process to modify the surface of the metal film into a metal nitride film; and performing a heat treatment process on the substrate to react the metal film on the bottom of the contact hole with the substrate to form a metal silicide film. .

According to another aspect of the present invention, there is provided a method of forming a metal wiring, the method including: forming a metal film having a uniform thickness on an insulating film having a contact hole exposing a surface of a substrate; Performing a nitriding process to modify the surface of the metal film into a metal nitride film; and performing a heat treatment process on the substrate to form a metal silicide film by reacting the metal film on the bottom of the contact hole with the substrate; And forming a contact plug and a bit line filling the contact hole in which the metal silicide layer is formed.

Accordingly, the metal silicide film forming method as described above may form a metal silicide film having a low contact resistance by a simple plasma nitriding process without performing a separate capping film forming process. In addition, by using a metal film including the metal nitride film formed by the plasma nitridation treatment as a barrier film without forming a barrier film necessary for forming a contact plug for filling a contact hole, the manufacturing time of the metal wiring can be significantly shortened.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention.

2 to 6 are cross-sectional views illustrating a method of forming a cobalt silicide layer and a bit line according to an exemplary embodiment of the present invention.

Referring to FIG. 2, first, gate electrodes 110 including gate spacers are formed on a semiconductor substrate 100, and then the source / drain regions 120 are formed by applying the gate electrode 110 as an ion implantation mask. . Subsequently, after forming the interlayer insulating layer covering the gate electrode 110, a chemical mechanical polishing (CMP) process, that is, a planarization process is performed to planarize the top surface of the interlayer insulating layer.

Subsequently, a photoresist pattern having a predetermined shape is formed to pattern the planarized interlayer insulating film. The interlayer insulating layer is etched by applying the formed photoresist pattern as an etch mask to form a contact hole 140 exposing the source / drain regions 120 between the gate electrodes 110. Due to the formation of the contact hole 140, the interlayer insulating layer is formed of the interlayer insulating layer pattern 130.

Referring to FIG. 3, the metal layer 150 for forming the metal silicide layer 170 may be formed on an upper surface of the interlayer insulating layer pattern 130, both side surfaces of the contact hole 140, and a bottom surface of the contact hole 140. Deposited to have a uniform thickness.

Here, the deposition process of the metal film 150 loads the substrate in the cassette of the load lock chamber of the PECVD apparatus, maintains the pressure in the load lock chamber in a vacuum state, and then transfers the substrate through a transfer means such as a robot arm. The deposition process is performed after being placed on the electrostatic chuck in the deposition chamber.

An example of the metal film 150 for forming the metal silicide film 170 may be a tungsten metal film or a cobalt metal film. In particular, a cobalt metal film is preferable. The cobalt metal film may be formed by applying methods consisting of CVD, PVD, and ALD. The cobalt metal film may have a thickness of 10 kPa to 500 kPa, but a thickness of about 100 kPa is preferable.

Referring to FIG. 4, the surface of the metal film 150 is modified to the metal nitride film 160 by performing a plasma nitridation process on the metal film 150. The thickness of the metal nitride film 160 modified from the metal film 150 is preferably about 25 mm.

When the metal film 150 is a cobalt film, the surface of the cobalt film is modified with a cobalt nitride film (CoN) by performing the plasma nitridation process, thereby forming a cobalt / cobalt nitride film (Co / CoN) from the cobalt film. The bilayer of is formed.

Specifically, the plasma nitriding treatment is performed in a state of maintaining a vacuum degree of 10 mtorr to 30 mtorr. Then, the semiconductor substrate 100 is in the range of room temperature to 900 ℃, nitrogen (50 ~ 5000sccm) atmosphere gas and argon (50 ~ 5000sccm) gas is injected, while applying an RF or DC source power of 100W to 1200W 5 The process is carried out for a time from seconds to 300 seconds. In this case, the plasma nitridation treatment is selected from a gas containing nitrogen selected from NH ₃ , N ₂ O and NO, a gas containing oxygen selected from O ₂ , O ₃ and H ₂ O, and a gas containing halogen element. One gas or a mixture of these gases is used as the atmosphere gas.

In this case, the plasma nitridation process is performed in situ after the deposition of the metal film 150 in a vacuum state, so that an oxide film is not integrally formed on the metal film 150. Therefore, the metal silicide layer 170 formed in a subsequent process may form a stable ohmic contact having a low contact resistance.

Referring to FIG. 5, a heat treatment process is performed in a deposition chamber having a temperature at which a silicidation reaction occurs, such that the metal film 150 on the bottom surface of the contact hole 140 reacts with the silicon of the substrate 100 to react with the metal silicide. The film 170 is formed. In this case, the heat treatment is a rapid thermal processing (RTP) method, it is preferably carried out for 30 seconds at a temperature of 460 ℃ to 900 ℃.

When the metal film 150 is a cobalt film, the metal silicide film 170 formed on the bottom surface of the contact hole 140 by a silicide reaction may be cobalt silicide film (CoSi) or according to a temperature at which the heat treatment process is performed. It may be formed of a cobalt dissilicide layer (CoSi ₂ ). Specifically, a cobalt silicide film (CoSi) is formed at the heat treatment temperature of 460 ° C to 600 ° C, and a cobalt dissilicide film (CoSi ₂ ) is formed at 600 ° C to 900 ° C.

In general, as the metal silicide having the ohmic contact in the bit line wiring process, cobalt dissilicide (CoSi ₂ ) having a small contact resistance is preferable. However, even though cobalt silicide (CoSi) is formed in the heat treatment process, there are a plurality of semiconductor processes having a condition in which cobalt silicide is phase transformed into cobalt dissilicide (CoSi ₂ ). Silicide (CoSi) may be formed.

The plasma nitridation process and the heat treatment process may be performed in situ in the same chamber. In addition, by performing the plasma nitridation process at a high temperature, the plasma nitridation process and the heat treatment process may be performed simultaneously. At this time, the plasma treatment is preferably performed between 460 ℃ to 900 ℃.

Accordingly, in the method of forming the metal silicide film, unlike the prior art, the metal silicide film may be formed by only at least one heat treatment step without performing the two-step heat treatment process, thereby effectively reducing the manufacturing time.

Referring to FIG. 6, a contact plug 180 and a bit line 182 may be formed in the contact hole 140 and the interlayer insulating layer pattern 130 on which the metal nitride layer 160 and the metal silicide layer 170 are formed. A conductive material layer (not shown) for forming is formed. The top surface of the conductive material layer is planarized to form the bit line 182. The conductive material layer may be made of tungsten, aluminum, titanium nitride (TiN) or tantalum nitride (TaN) material. In particular, tungsten is preferred.

In this case, the metal nitride layer 160 may prevent the material of the contact plug 180 filling the contact hole 140 from being diffused to the adjacent interlayer insulating layer as well as the function of the anti-oxidation layer of the metal layer 150 described above. It also has the function of a barrier film. Therefore, unlike the conventional technology, since a separate barrier film deposition process is not required, the manufacturing time of the semiconductor device may be further shortened.

The conductive material layer is patterned to form the contact plug 180 and the bit line 182. Specifically, the contact plug 180 and the bit line 182 are formed by performing an anisotropic etching process using a photoresist pattern on the conductive material layer and using the photoresist pattern as an etching mask.                     

Although not shown, after forming the contact plug 180 and the bit line 182, a silicon nitride film for removing the photoresist pattern and forming a bit line spacer on the bit line 182 is formed to have a predetermined thickness. Form to have. Subsequently, the bit back structure including the nitride film spacer is completed by performing an etch back process on the silicon nitride film.

7 to 9 are cross-sectional views illustrating a method of forming a cobalt silicide layer and a bit line according to another exemplary embodiment of the present invention.

First, a gate electrode 110, a source / drain region 120, an interlayer insulating layer pattern 130, a contact hole 140, a metal layer (not shown), a metal nitride layer (not shown), and a metal silicide are formed on a semiconductor substrate. A film 210 is formed. The elements as described above may be formed in the same manner as the parts previously described with reference to FIGS. 2 to 5, and thus, further detailed description thereof will be omitted.

Referring to FIG. 7, the metal film and the metal nitride film which are not involved in the formation of the metal silicide film 210 are removed by performing a wet etching process, and a second heat treatment process is performed on the substrate 100 to form the metal. The silicide layer 210 is stabilized.

Specifically, the substrate 100 is immersed in the etchant for a predetermined time to remove the metal film and the metal nitride film except for the metal silicide film 210 existing on the bottom surface of the contact hole 140 of the interlayer insulating film pattern 130. Subsequently, a cleaning process for removing the etching liquid present in the substrate 100 from which the metal film and the metal nitride film are removed, and a drying process for drying the substrate 100 are performed. In addition, after the substrate 100 having the etching process is transferred into the heat treatment chamber, a second heat treatment process is performed on the substrate 100 to stabilize the metal silicide layer 210. Here, the heat treatment is performed by RTP method, 30 seconds at a temperature of about 850 ℃.

In particular, when the metal silicide layer 210 is a cobalt silicide layer (CoSi), the metal silicide layer stabilized by the second heat treatment process is formed of cobalt dissilicide (CoSi ₂ ).

Referring to FIG. 8, the barrier layer 220 is deposited to have a thickness of about 100 μs on the contact hole 140 and the interlayer dielectric layer pattern 130 on which the metal silicide layer 210 is formed. The barrier film 220 is a prevention film for preventing the metal material constituting the contact plug 230 from penetrating into the adjacent interlayer insulating film.

Examples of the barrier film 220 include titanium, titanium nitride, or titanium / titanium nitride film (Ti / TiN). In particular, a titanium / titanium nitride film is preferable. In addition, the formation of the barrier film 220 may be a process of additionally applying a heat treatment effect to the metal silicide film 210, and thus the second heat treatment process may be omitted. That is, while forming the barrier layer 220, the metal silicide layer 210 may be stabilized at the same time.

Referring to FIG. 9, a bit line is formed on the contact plug 230 filling the barrier hole 220 and the metal silicide layer 210, and the interlayer insulating layer pattern 130. A conductive material layer (not shown) for forming 240 is simultaneously formed. The top surface of the conductive material layer is planarized to form the bit line 240. The conductive material layer may include tungsten, aluminum, titanium nitride (TiN) or tantalum nitride (TaN). In particular, tungsten is preferred.

Subsequently, the bit line structure may be completed by patterning the conductive material layer to form a bit line 240 and forming a bit line spacer (not shown) on the side of the bit line 240. Detailed description thereof will be omitted since it is the same as the method of forming the bit line according to the above-described embodiment with reference to FIGS. 2 to 6.

This embodiment is similar to the bit line forming process according to the prior art, but after forming the metal film without forming a capping film separately from a material different from the metal film, by performing a plasma nitridation process in a vacuum state is maintained, A predetermined oxide film is prevented from being formed on the metal film before capping film deposition. Therefore, if the bit line is manufactured according to the present embodiment, the contact resistance can be easily lowered compared with the prior art.

10 and 11 are cross-sectional views illustrating a method of forming a cobalt silicide layer and a bit line according to still another exemplary embodiment of the present invention.

First, a gate electrode 110, a source / drain region 120, an interlayer insulating film pattern 130, a contact hole 140, a metal film 310, a metal nitride film 320, and a metal silicide film ( 330 and a conductive material layer (not shown). The elements as described above may be formed in the same manner as the parts previously described with reference to FIGS. 2 to 6, and thus, further detailed description thereof will be omitted.

Referring to FIG. 10, the metal layer 310, the metal nitride layer 320, and the conductive material layer on the interlayer insulating layer 130 may be planarized to expose the upper portion of the interlayer insulating layer pattern 130. The contact plug 340 is formed in the contact hole 140 by partially removing the contact plug 140. The planarization process is performed using an etch back process or a CMP process.

A second barrier layer 350 is formed on the exposed interlayer insulating layer pattern 130 and the contact plug 340 to have a uniform thickness. The second barrier film 350 is a still film for the CMP process used in the bit line 360 forming process. Here, the second barrier film 350 may use one of titanium, titanium nitride, and titanium / titanium nitride films. In particular, it is preferable to use a titanium / titanium nitride film.

A second conductive material layer (not shown) is formed on the second barrier layer 350 to form the bit line 360 electrically connected to the contact plug 340. The second conductive material layer may use one of tungsten, aluminum, titanium nitride, or tantalum nitride. In particular, the second conductive material layer is preferably formed of the same material as the contact plug 340.

The second conductive material layer is patterned to form a bit line 360 electrically connected to the contact plug 340. Subsequently, the bit line structure is completed by forming bit line spacers on the side surfaces of the bit line 360. The elements as described above may be formed in the same manner as the previously described parts in the above embodiment, and thus further detailed description thereof will be omitted.

As described above, when forming a metal silicide film for forming an ohmic contact in a metal wiring manufacturing process of a semiconductor device, a high temperature plasma nitridation treatment is performed on the surface of the metal film without performing a separate capping film process and a two-step heat treatment process. By doing this, the metal silicide film formation time can be significantly shortened, and the contact resistance of the metal wiring can be easily lowered. Therefore, there is an effect that can stably form a semiconductor device requiring a fine pattern.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

Claims (7)

Forming a metal film having a uniform thickness on the insulating film having a contact hole exposing a surface of the substrate; Performing a plasma nitridation process on the metal film to modify the surface of the metal film into a metal nitride film; And And performing a heat treatment process on the substrate to react the metal film on the bottom surface of the contact hole with the substrate to form a metal silicide film. The method of claim 1, wherein the plasma nitridation process and the heat treatment process are performed in situ. The method of claim 1, wherein the plasma nitridation process and the heat treatment process are performed at the same time. Forming a metal film having a uniform thickness on the insulating film having a contact hole exposing a surface of the substrate; Performing a plasma nitridation process on the metal film to modify the surface of the metal film into a metal nitride film; Performing a heat treatment process on the substrate to form a metal silicide layer by reacting the metal film on the bottom surface of the contact hole with the substrate; And And forming a contact plug and a bit line to fill the contact hole in which the metal silicide layer is formed. The method of claim 4, wherein after forming the metal silicide film, Removing the metal film and the metal nitride film not involved in forming the metal silicide film; Performing a second heat treatment process on the substrate to stabilize the metal silicide layer on a bottom surface of the contact hole; And And forming a barrier film on the inner surface of the contact hole and the stabilized metal silicide film. The method of claim 4, wherein the forming of the bit line comprises: Forming a conductive material layer on the metal nitride layer to fill the contact hole in which the metal silicide layer is formed; And Patterning the conductive material layer to form the bit line. The method of claim 4, wherein the forming of the bit line comprises: Forming a first conductive material layer on the metal nitride layer, the first conductive material layer filling the contact hole in which the metal silicide layer is formed; Forming a contact plug in the contact hole by removing the metal film, the metal nitride film, and the first conductive material layer on the insulating film to expose an upper surface of the insulating film; Forming a second barrier film on the exposed insulating film and the contact plug; Forming a second conductive material layer on the second barrier film; And Patterning the second layer of conductive material to form the bit line electrically connected to the contact plug.

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