WO2025110419A1 - Method for forming metal thin film - Google Patents

Abstract

In the method for forming a metal thin film, an insulation pattern including a hole is first formed on a substrate. In a method of forming a metal thin film, an insulation pattern including a hole is formed on a substrate. A metal nucleation layer is formed along a top surface, a sidewall, and a bottom surface of the insulation pattern. The surface of the metal nucleation layer is pretreated with a nitrogen-containing deposition inhibiting gas. A metal bulk layer is formed on the pretreated metal nucleation layer. Before the step of forming the metal bulk layer, the pre-treated metal nucleation layer is post-treated with a reactive dose gas to control a deposition rate of the metal bulk layer.

Description

Method for forming a metal thin film

The present invention relates to a method for forming a metal thin film, and more specifically, to a method for forming a metal thin film capable of controlling the growth thickness (incubation thickness) of the metal thin film, thereby forming the thin film without occurrence of defects such as seams or voids in a three-dimensional hole such as a contact plug.

As fine processes are commercialized in the semiconductor industry, high aspect ratio challenge patterns are being utilized. There is an increasing demand for the development of a deposition method for a metal thin film that gap-fills patterns with such high aspect ratios without the occurrence of defects such as seams and voids.

However, since the above challenge patterns vary in diameter, depth, etc., and the optimal growth thickness required for seamless gap-fill differs depending on the shape of the pattern, there is a disadvantage in that various trial and errors are required to secure suitable process conditions for performing seamless gap-fill depending on the shape of the hole, which significantly increases time and cost consumption.

The present invention provides a method for forming a metal thin film capable of improving electrical characteristics.

According to one embodiment of the present invention, a method for forming a metal thin film includes the steps of: preparing a substrate including an insulating pattern defining an opening region; forming a metal nucleation layer along an upper surface, a side wall, and a bottom surface of the insulating pattern on which the opening region is formed; pretreating a surface of the metal nucleation layer with a nitrogen-containing deposition-inhibiting gas; and forming a metal bulk layer on the pretreated metal nucleation layer. Prior to the step of forming the metal bulk layer, the pretreated metal nucleation layer may be post-treated with a reactive dose gas in order to control a deposition rate of the metal bulk layer.

According to another embodiment of the present invention, a method for forming a metal thin film may include the steps of: preparing a substrate including an insulating pattern defining an opening area; forming a metal nucleation layer along a surface of the insulating pattern with the defined opening area; forming a first metal bulk layer on the metal nucleation layer; pretreating the first metal bulk layer with a nitrogen-containing deposition-inhibiting gas; and forming a second metal bulk layer on the pretreated first metal bulk layer. Prior to the step of forming the second metal bulk layer, the pretreated first metal bulk layer may be post-treated with a reactive dose gas in order to control a deposition rate of the second metal bulk layer.

In a method for forming a metal thin film according to an embodiment, a metal nucleation layer or a metal bulk layer is pretreated with a nitrogen-containing deposition-inhibiting gas, and then the pretreated metal nucleation layer or the metal bulk layer is post-treated with a reactive dose gas. This method reduces the deposition delay effect caused by the deposition-inhibiting gas by replacing metal-nitrogen bonds with metal-hydrogen bonds, so that the growth thickness can be easily controlled according to the shape (size and depth) of the hole, enabling easy seamless gap-fill for holes of various shapes.

In addition, in the method for forming a metal thin film according to the embodiment, the growth time (incubation time) of an unnecessary metal bulk layer can be reduced, thereby increasing the unit time production (UPEH).

Figure 1 is a cross-sectional view of a substrate showing a metal film including a typical core.

FIG. 2 is a flow chart for explaining a method for forming a metal thin film according to one embodiment of the present invention.

FIGS. 3A to 3E are cross-sectional views of each step of a process for explaining a method for forming a metal thin film according to one embodiment of the present invention.

FIG. 4 is a flowchart for explaining a method for forming a metal thin film according to one embodiment of the present invention.

FIGS. 5A to 5F are process cross-sectional views showing each step for explaining a method for forming a metal thin film according to one embodiment of the present invention.

FIG. 6 is a cross-sectional view showing an example of a thin film deposition device according to one embodiment of the present invention.

Figure 7 is a graph showing the results of evaluating the change in the thickness of a thin film according to the hydrogen gas supply flow rate of a thin film formed by a method according to one embodiment of the present invention.

In general, in order to gap-fill an opening region having a high aspect ratio formed inside an insulating layer (10), a metal barrier layer (MB) is formed on the inner wall of the opening region, and a metal nucleus formation layer (MN) is formed on the upper portion of the metal barrier layer (MB). Next, a metal bulk layer (B), such as tungsten, is deposited on the upper portion of the metal nucleus formation layer (MN). In the metal thin film forming method as described above, the deposition speed of the metal bulk layer (B) tends to decrease in the depth direction of the opening region from the surface of the insulating layer (10). This occurs due to the difference in the deposition speeds of the metal thin films on the upper and lower portions of the opening region, and since the deposition speed of the metal bulk layer (B) on the upper portion of the opening region is fast, the metal thin film is deposited in an overhang (OV) shape, causing a defect such as a seam on the inside of the opening region (see FIG. 1).

In order to solve this problem, a method of gap-filling the opening region by forming a metal-nitrogen complex on the upper part of the insulating layer (10) above the opening region through deposition-inhibiting gas treatment can be used. When the opening region is treated using the deposition-inhibiting gas, the concentration of the deposition-inhibiting gas is expected to gradually decrease along the depth direction of the opening region. That is, a relatively high concentration of deposition-inhibiting gas is provided to the upper edge part of the opening region. In this state, when a metal film is deposited inside the opening region, the deposition of the metal film is suppressed on the upper part of the opening region, and the deposition of the metal film proceeds relatively smoothly on the lower side of the opening region.

Specifically, a method has been used in which a tungsten nucleation layer (MN) is formed on an aperture area to gap-fill a tungsten thin film on an aperture area, and then a tungsten bulk layer (B) is deposited on the tungsten nucleation layer (MN), in which the tungsten nucleation layer (MN) is treated with a nitrogen-containing deposition inhibitor gas activated by plasma before depositing the tungsten bulk layer (B).

As described above, when the aperture area has a high aspect ratio, the concentration of tungsten-nitrogen bonds formed on the tungsten nucleation layer (MN) becomes uneven as the depth of the aperture area increases, and tungsten deposition is temporarily delayed only at the top portion, so that a tungsten thin film layer grows upward from the bottom portion, thereby preventing the occurrence of defects such as seams. At this time, the degree of tungsten deposition delay due to the deposition-inhibiting gas treatment can be expressed in numerical values such as the growth thickness (incubation thickness) and the growth time (incubation time).

However, since the aperture area has different diameters, depths, etc., the optimal growth thickness required for seamless gapfill is different depending on the shape of the aperture area. In addition, there is a limit to quantitatively controlling the growth thickness by only controlling variables such as the flow rate and treatment time of the deposition-inhibiting gas in the nitrogen-containing deposition-inhibiting gas treatment step, so that in order to perform seamless gapfill depending on the shape of the aperture area, various trial and errors are required to secure suitable process conditions, which may significantly increase time and cost consumption.

Fig. 2 is a flow chart for explaining a method for forming a metal thin film according to one embodiment of the present invention. Figs. 3a to 3e are cross-sectional views of each step of the process for explaining a method for forming a metal thin film according to one embodiment of the present invention.

Referring to FIGS. 2 and 3, a method for forming a metal thin film according to one embodiment includes a step (S110) of providing a substrate (10) including an insulating pattern (11) having an opening region (P); a step (S120) of forming a metal nucleus formation layer (13) on the opening region (P) and the insulating pattern (11); a step (S130) of pretreating the metal nucleus formation layer (13) with a nitrogen-containing deposition-inhibiting gas; a step (S140) of posttreating the pretreated metal nucleus formation layer (13) with a reactive dose gas; and a step (S150) of forming a metal bulk layer (15) on the surface-treated metal nucleus formation layer (13). As an exemplary embodiment, the opening region (P) may have a trench or hole structure.

A method for forming a metal thin film according to one embodiment can be performed using a thin film forming apparatus (200) including a process chamber (210), a substrate mounting portion (220), a gas injection portion (230), and a remote plasma generation portion. The thin film forming apparatus (200) can have various conventional forms used for performing a plasma-enhanced chemical vapor deposition process or an atomic layer deposition process, which will be described in more detail below.

First, the step (S110) of preparing a substrate (10) including an insulating pattern (11) including the opening area (P) may include a step of forming at least one insulating film on top of a bare substrate or a substrate on which circuits are formed.

The substrate (10) may include materials such as silicon, silicon oxide, strained silicon, silicon on insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium, arsenic, glass, sapphire, and any other materials, such as metals, metal nitrides, metal alloys, and other conductive materials. The insulating pattern (11) may include, for example, at least one insulating film, an insulating film including alternately and repeatedly stacked silicon oxide films and silicon nitride films, at least one low-k dielectric film, or an insulating film including at least one high-k dielectric film. In some cases, the insulating pattern (11) may include at least one conductive material therein. The insulating pattern (11) may be pretreated by at least one processing process selected from the group consisting of polishing, etching, reduction, oxidation, hydroxylation, annealing, and baking.

The above insulating film can be patterned by a predetermined etching process to form an opening region (P) within the insulating film, thereby forming an insulating pattern (11). At this time, the insulating film has a sufficiently thick thickness, and the opening region (P) has a sufficiently narrow line width, so that the opening region (P) can satisfy a high aspect ratio.

In addition, a metal barrier layer (12), such as a titanium nitride film (TiN layer), may be formed on the side wall of the opening area (P), that is, the side wall of the insulating pattern (11), but is not limited thereto.

In a method for forming a metal thin film according to one embodiment, the metal thin film means that it includes both a metal nucleation layer (13) and a metal bulk layer (15). The metal thin film may have a structure including a single metal nucleation layer (13) and a single metal bulk layer (15), and may also have a structure including a plurality of metal nucleation layers (13) and a plurality of metal bulk layers (15).

Next, in the step (S120) of forming a metal nucleus formation layer (13), a metal nucleus formation layer (13) is formed on the surface of the insulating pattern (11) and the opening area (P).

In this step, a metal precursor gas and a hydrogen-containing gas can be supplied respectively to form a metal nucleation layer (13) on the bottom surface of the insulating pattern (11) and the opening area (P).

The above metal nucleation layer (13) can be deposited to have a uniform thickness on the bottom surface of the insulating pattern (11) and the opening area (P). The metal nucleation layer (13) can be formed to a thickness of 1 to 20 nm.

For example, when the metal nucleation layer (13) is formed using tungsten, the metal precursor gas may include tungsten fluoride (WF ₆ ). In addition, the hydrogen-containing gas may include at least one of silane (Si _X H _Y ) and borane. Representative examples of the silane include monosilane (SiH ₄ ), disilane (Si ₃ H ₆ ), and trisilane (Si ₃ H ₈ ). Representative examples of the borane include diborane (B ₂ H ₆ ).

In this step, the metal nucleation layer (13) can be formed using atomic layer deposition (ALD), but is not necessarily limited thereto.

More specifically, in this step, a metal precursor gas and a hydrogen-containing gas are respectively supplied, and a metal nucleation layer (13) can be formed by an atomic layer deposition method.

Accordingly, a metal nucleation layer (13) is formed on the opening area (P), and at this time, the thickness of the metal nucleation layer (13) formed on the upper portion of the opening area (P) may be thicker than the thickness of the metal nucleation layer (13) formed on the lower and lower side surfaces of the opening area (P).

Next, in the pretreatment step (S130), the metal nucleation layer (13) is pretreated with a nitrogen-containing deposition inhibitor gas.

The above nitrogen-containing deposition-inhibiting gas reacts with the metal on the surface of the metal nucleation layer (13) to form a metal-nitrogen bond, so that when the metal bulk layer (15) is formed, the nitrogen component prevents the dissociation of the hydrogen component, thereby inducing a deposition delay effect on the upper side where the deposition-inhibiting gas is formed relatively thickly, thereby preventing the formation of a seam due to overhang caused by excessively rapid deposition of the metal thin film on the upper side of the opening area (P).

In this step, considering the mean free path of the nitrogen-containing deposition-inhibiting gas, it is relatively difficult for the deposition-inhibiting gas to reach the lower side wall and lower surface of the opening area (P) from the upper side where the deposition-inhibiting gas is supplied, or even if it does reach, a small amount of the deposition-inhibiting gas is adsorbed, so that the formation of the metal bulk layer (15) is delayed on the upper side of the opening area (P) and the metal bulk layer (15) is deposited upward from the lower side toward the upper side.

The above nitrogen-containing deposition-suppressing gas may include at least one of ammonia (NH ₃ ) gas, amine (NH _X ) gas, nitrogen fluoride (NF ₃ ) gas, and nitrogen (N ₂ ) gas.

In this step, the nitrogen-containing deposition-inhibiting gas may be activated by plasma to form nitrogen radicals, and the process may be performed in a state where plasma is formed so that the formed nitrogen radicals react with the metal nucleation layer (13). To this end, in this step, the metal nucleation layer (13) may be pretreated with the deposition-inhibiting gas using a plasma-enhanced chemical vapor deposition device. The nitrogen radicals may be generated by activating the nitrogen-containing deposition-inhibiting gas using a remote plasma generator, but are not limited thereto.

Next, in the post-processing step (S140), the pre-treated metal nucleation layer (13) is post-processed with a reactive dose gas. As described above, if the pre-processed metal nucleation layer (13) is post-processed with a reactive dose gas before forming the metal bulk layer (15), the deposition speed of the metal bulk layer (15) formed in the step to be described later can be controlled. That is, in this step, by exposing the metal nucleation layer (13) pre-processed with a nitrogen-containing deposition-inhibiting gas to a reactive dose gas for post-processing, the growth speed of the metal thin film, which is delayed when the metal bulk layer (15) is formed due to metal-nitrogen bonding, is alleviated, thereby improving the growth speed of the metal thin film.

The above reactive dose gas may include at least one of a hydrogen-containing gas and a fluorine-containing gas. The above reactive dose gas may replace a metal-nitrogen (M-F) bond formed on the surface of a metal nucleation layer (13) pretreated with the deposition-inhibiting gas with a metal-hydrogen (M-H) bond or induce a nitrogen-fluorine (N-F) bond to remove nitrogen from the metal nucleation layer (13), thereby alleviating the deposition delay effect caused by the deposition-inhibiting gas treatment, thereby increasing the deposition rate of the metal bulk layer (15).

In particular, the reactive dose gas may include at least one of hydrogen (H ₂ ) gas, ammonia (NH ₃ ) gas, silane gas (Si _X H _Y ), diborane (B ₂ H ₆ ) gas, and tungsten fluoride (WF ₆ ) gas.

In this step, the reactive dose gas may be supplied at a flow rate of 1 to 5,000 sccm and the post-processing may be performed under a pressure condition of 1 to 300 Torr. If the flow rate of the reactive dose gas is less than 1 sccm or less than 1 Torr, the deposition delay alleviation effect may be insufficient. If the flow rate of the reactive dose gas exceeds 5,000 sccm or 300 Torr, the deposition delay effect may be reduced, and there is a concern that an overhang may occur when forming the metal bulk layer (15).

In addition, in this step, the post-processing can be performed by supplying the reactive dose gas for 1 to 30 seconds. In this way, by controlling the supply time of the reactive dose gas, the incubation thickness, the incubation time, and the incubation rate can be selectively controlled in various ways according to the shape of the opening area (P).

Next, in the step (S150) of forming a metal bulk layer (15), a metal bulk layer (15) is formed on the metal nucleation layer (13) that has undergone pretreatment and posttreatment.

The above metal bulk layer (15) may include the same metal component as the metal nucleation layer (13) and may grow on top of the metal nucleation layer (13). At this time, the growth speed and thickness of the metal bulk layer (15) are controlled in the upper region of the opening region (P) that has been pretreated with a nitrogen-containing deposition-inhibiting gas and post-treated with a hydrogen-containing gas, and the deposition speed is controlled in the upper and lower regions of the opening region (P), so that a metal bulk layer (15) that can prevent the occurrence of defects such as seams can be formed.

In this step, the formation of the metal bulk layer (15) can be performed using various conventional methods utilized to form a metal thin film on an insulating pattern (11) by supplying a metal precursor gas and a silicon source gas, respectively.

Specifically, in this step, a metal precursor gas and a hydrogen-containing gas are supplied respectively, and a metal bulk layer (15) that gap-fills the opening area (P) can be formed using any one of an ALD method, a PEALD method, a CVD method, and a PECVD method.

In a method for forming a metal thin film according to one embodiment, the metal nucleation layer (13) and the metal bulk layer (15) can be formed using various conventional metal materials that are used to form a conductive layer on the opening region (P), respectively. Specifically, the metal thin film can be formed using at least one of tungsten (W), cobalt (Cu), ruthenium (Ru), and copper (Cu). To this end, a metal precursor gas including the metal and a hydrogen-containing gas can be supplied when forming the metal nucleation layer (13) and the metal bulk layer (15). In particular, the metal thin film can be formed using tungsten.

Accordingly, the method for forming a metal thin film according to one embodiment can be utilized as a method for forming a gate, a storage node, etc., and can be utilized for manufacturing semiconductor devices such as NAND, DRAM, etc.

In addition, in the method for forming a metal thin film according to one embodiment, only a method of forming a metal thin film by performing the step of forming a metal nucleus formation layer and the step of forming a metal bulk layer once each, or performing the step of forming a metal nucleus formation layer and then forming a metal bulk layer twice is described, but is not limited thereto.

Specifically, in a method for forming a metal thin film according to one embodiment, the steps of forming a metal nucleation layer and forming a metal bulk layer can be alternately performed two or more times, and among these multiple processes, a process of pretreatment with a nitrogen-containing deposition-inhibiting gas and a process of posttreatment with a reactive dose gas can be selectively introduced.

At this time, the step (S120) of forming a metal nucleus formation layer (13) and the step (S150) of forming a metal bulk layer (15) can be alternately performed two or more times, but the step of forming a metal nucleus formation layer (S120) must be performed first, and the step of forming a metal bulk layer (S150) must be performed in the last step.

In addition, when selectively introducing a nitrogen-containing deposition-inhibiting gas pretreatment process and a reactive dose gas posttreatment process during multiple deposition processes, the posttreatment is applied immediately after the pretreatment. For example, ① metal nucleation layer (13) formation, ② nitrogen plasma pretreatment, and ③ reactive gas posttreatment are performed in sequence, and ④ a metal bulk layer (15) is formed.

Meanwhile, Fig. 4 is a process diagram showing a method for forming a metal thin film according to one embodiment. Fig. 5 is a state diagram showing each step of a method for forming a metal thin film according to one embodiment.

Referring to FIGS. 4 and 5, a method for forming a metal thin film according to one embodiment includes a step of preparing an insulating pattern (11) having an opening region (P) formed therein (S210); a step of forming a metal nucleus formation layer (13) on a bottom surface of the opening region (P) and an upper portion of the insulating pattern (11) (S220); a step of forming a first metal bulk layer (15a) on the metal nucleus formation layer (13) (S230); a step of pretreating the first metal bulk layer (15a) with a nitrogen-containing deposition-inhibiting gas (S240); and a step of posttreating the pretreated first metal bulk layer (15a) with a reactive dose gas (S250); and a step of forming a second metal bulk layer (15b) on the posttreated first metal bulk layer (15a) (S260).

The step (S210) of preparing the above-mentioned insulating pattern (11) and the step (S220) of forming the metal nucleus formation layer (13) utilize the same method as described above, so a detailed description thereof will be omitted.

In the step (S230) of forming the first metal bulk layer (15a), the first metal bulk layer (15a) is formed on the metal core formation layer (13).

In this step, the same metal component as the metal nucleation layer (13) may be included and may be grown on top of the metal nucleation layer (13).

In this step, the formation of the first metal bulk layer (15a) can be performed using various conventional methods utilized to form a metal thin film on an insulating pattern (11) by supplying a metal precursor gas and a silicon source gas, respectively.

The first metal bulk layer (15a) is a metal layer formed based on the metal nucleation layer (13) and can be grown to have a thickness of 10 to 30% of the entrance width of the opening area (P). The first metal bulk layer (15a) can be formed by supplying a metal precursor gas and a hydrogen-containing gas, respectively, and using any one of the ALD method, the PEALD method, the CVD method, and the PECVD method.

Next, in the preprocessing step (S240), the first metal bulk layer (15a) can be preprocessed with a nitrogen-containing deposition-suppressing gas.

The above nitrogen-containing deposition-inhibiting gas reacts with the metal on the surface of the first metal bulk layer (15a) to form a metal-nitrogen bond, so that when the second metal bulk layer (15b) is formed, the nitrogen component prevents the dissociation of the hydrogen component, thereby inducing a deposition delay effect on the upper side where the deposition-inhibiting gas is formed relatively thickly, thereby preventing the formation of a seam due to overhang caused by excessively rapid deposition of the metal thin film on the upper side of the opening area (P).

In this step, considering the mean free path of the nitrogen-containing deposition-inhibiting gas, it is relatively difficult for the deposition-inhibiting gas to reach the lower sidewall and lower surface of the opening area (P) from the upper side where the deposition-inhibiting gas is supplied, or even if it does reach, a small amount of the deposition-inhibiting gas is adsorbed, so that the formation of the second metal bulk layer (15b) is delayed on the upper side of the opening area (P) and the second metal bulk layer (15b) is deposited upward from the lower side toward the upper side.

In this step, the nitrogen-containing deposition-inhibiting gas may be activated by plasma to form nitrogen radicals, and the process may be performed in a state where plasma is formed so that the formed nitrogen radicals react with the first metal bulk layer (15a). To this end, in this step, the first metal bulk layer (15a) may be pretreated with the deposition-inhibiting gas using a plasma-enhanced chemical vapor deposition device. The nitrogen radicals may be generated by activating the nitrogen-containing deposition-inhibiting gas using a remote plasma generator, but are not limited thereto.

The above nitrogen-containing deposition-suppressing gas may include at least one of ammonia (NH ₃ ) gas, amine (NH _X ) gas, nitrogen fluoride (NF ₃ ) gas, and nitrogen (N ₂ ) gas.

Next, in the post-processing step (S250), the pre-processed first metal bulk layer (15a) can be post-processed with a reactive dose gas.

As described above, if the first metal bulk layer (15a) that has been pretreated before forming the second metal bulk layer (15b) is post-treated with a reactive dose gas, the deposition speed of the second metal bulk layer (15b) formed in the step to be described later can be controlled. That is, in this step, by exposing the first metal bulk layer (15a) that has been pre-treated with a nitrogen-containing deposition-inhibiting gas to a reactive dose gas for post-treatment, the growth speed of the metal thin film that is delayed when forming the second metal bulk layer (15b) due to metal-nitrogen bonds is alleviated, thereby improving the growth speed of the metal thin film.

The above reactive dose gas may include at least one of a hydrogen-containing gas and a fluorine-containing gas. The above reactive dose gas may replace a metal-nitrogen (M-F) bond formed on the surface of a metal nucleation layer (13) pretreated with the deposition-inhibiting gas with a metal-hydrogen (M-H) bond or induce a nitrogen-fluorine (N-F) bond to remove nitrogen from the metal nucleation layer (13), thereby alleviating the deposition delay effect caused by the deposition-inhibiting gas treatment, thereby increasing the deposition rate of the metal bulk layer (15).

In particular, the reactive dose gas may include at least one of hydrogen (H ₂ ) gas, ammonia (NH ₃ ) gas, silane gas (Si _X H _Y ), diborane (B ₂ H ₆ ) gas, and tungsten fluoride (WF ₆ ) gas.

In this step, the reactive dose gas may be supplied at a flow rate of 1 to 5,000 sccm and the post-processing may be performed under a pressure condition of 1 to 300 Torr. If the flow rate of the reactive dose gas is less than 1 sccm or less than 1 Torr, the deposition delay alleviation effect may be insufficient. If the flow rate of the reactive dose gas exceeds 5,000 sccm or 300 Torr, the deposition delay effect may be reduced, and there is a concern that an overhang may occur when forming the metal bulk layer (15).

In addition, in this step, the post-processing can be performed by supplying the reactive dose gas for 1 to 30 seconds. In this way, by controlling the supply time of the reactive dose gas, the incubation thickness, the incubation time, and the incubation rate can be selectively controlled in various ways according to the shape of the opening area (P).

Next, in the step (S260) of forming a second metal bulk layer (15b), a second metal bulk layer (15b) is formed on the post-processed first metal bulk layer (15a).

In this step, a second metal bulk layer (15b) can be formed on a first metal bulk layer (15a) that has been post-processed using the same method as the method for forming the first metal bulk layer (15a) described above.

Specifically, the second metal bulk layer (15b) can also be formed by supplying a metal precursor gas and a hydrogen-containing gas, respectively, and using one of the ALD method, the PEALD method, the CVD method, and the PECVD method to gap-fill the opening area (P).

In the method for forming a metal thin film according to the embodiment described above, the metal nucleation layer (13) or the metal bulk layer (15) is pretreated with a nitrogen-containing deposition-inhibiting gas, and then the pretreated metal nucleation layer (13) or the metal bulk layer (15) is post-treated with a reactive dose gas, thereby replacing the metal-nitrogen bond with a metal-hydrogen bond, thereby reducing the deposition delay effect caused by the deposition-inhibiting gas. Accordingly, the growth thickness can be easily controlled according to the shape (size and depth) of the opening area (P), and easy seamless gap-fill is possible for various shapes of opening areas (P).

In addition, in the method for forming a metal thin film according to the embodiment, the growth time (incubation time) of an unnecessary metal bulk layer (15) can be reduced, thereby increasing the unit time production (UPEH).

Meanwhile, a thin film deposition device according to one embodiment can be performed by utilizing various types of conventional PEALD or PECVD devices used to gap-fill an opening area (P) formed in an insulating pattern (11) with a metal thin film.

Specifically, a thin film deposition device (200) according to one embodiment may include a process chamber (210) defining a processing space (210a). An insulating film mounting portion (220) supporting an insulating pattern (11) in which an opening area (P) is formed is installed inside the process chamber (210). The insulating film mounting portion (220) may include a heater (not shown) for heating the substrate (10).

A gas injection unit (230) may be installed on the ceiling of the above processing space (210a) to supply a metal precursor gas, a hydrogen-containing gas, a nitrogen-containing deposition-inhibiting gas, and a reactive dose gas to the processing space (210a), respectively. The gas injection unit (230) may include a showerhead having a plurality of injection holes formed therein for respectively injecting the metal precursor gas, the hydrogen-containing gas, the nitrogen-containing deposition-inhibiting gas, and the reactive dose gas toward the insulating film settling unit (220).

In addition, the insulating film mounting portion (220) may include a stage (221) on which the substrate (10) on which the insulating pattern (11) is formed is mounted, and a hollow support portion (222). The hollow support portion (222) may be located at the central bottom of the stage (221) and may support the stage (221). The hollow support portion (222) may have a passage (242) in the center.

The above thin film deposition device (200) supplies a nitrogen-containing deposition-inhibiting gas to a remote plasma generating unit (not shown), and nitrogen radicals (N) activated by the plasma can be adsorbed on the surface of the metal nucleation layer (13) or the first metal bulk layer (15a). At this time, the insulating 10) dl has a structure in which a high aspect ratio opening region (P) is formed. Accordingly, the nitrogen radicals (N*) are mostly adsorbed on the opening region (P) located relatively close to the gas injection unit (230) or on the upper and side walls of the metal barrier film. On the other hand, considering its mean free path, the nitrogen-containing deposition-inhibiting gas is difficult to reach the lower side wall of the opening region (P) located relatively far from the gas injection unit (230) and the upper part of the semi-bulk layer (130), or even if it reaches, a small amount of the nitrogen-containing deposition-inhibiting gas may be adsorbed.

Meanwhile, the thin film deposition device (200) according to one embodiment may further include an edge gas path (240). The edge gas path (240) may be provided inside the insulating film mounting portion (220). The edge gas path (240) may be communicated with the passage (242) located inside the hollow support portion (222). In the present embodiment, argon (Ar) gas may be used as the deposition prevention gas, and hereinafter, the deposition prevention gas in the present embodiment may be described as an edge gas.

In order to support the substrate (10), an edge ring (250) may be further provided on the upper edge of the insulating film mounting portion (220). The edge ring (250) is spaced apart from the stage (221) by a predetermined distance so that the edge gas can be delivered to the upper portion of the substrate (10). The unexplained symbol D1 of FIG. 6 may indicate a door for loading or unloading a substrate (10) on which an insulating pattern (11) including the opening area (P) is formed.

A thin film deposition device (200) according to one embodiment can supply an edge gas through the gas delivery passage (242) when supplying a deposition-inhibiting gas activated by plasma. The edge gas can be supplied for the purpose of preventing nitrogen radicals included in the deposition-inhibiting gas activated by plasma during pretreatment from penetrating between the substrate (10) and the substrate mounting portion (220). Furthermore, the edge gas can be provided in the metal nucleus formation layer (13) formation step and the metal bulk layer (15) formation step to prevent a metal thin film from being unevenly deposited on the lower surface of the substrate (10).

In addition, although not shown, the thin film deposition device may include a remote plasma generator equipped with a plasma power source. The remote plasma generator applies plasma power to activate a nitrogen-containing deposition-inhibiting gas by plasma to form and supply nitrogen radicals.

Hereinafter, the present invention will be described in more detail by way of examples.

The presented examples are only specific examples of the present invention and are not intended to limit the technical scope of the present invention.

<Example 1>

First, an insulating film having a titanium nitride film formed in an aperture region and an upper portion of the aperture region was prepared. Next, tungsten fluoride (WF ₆ ) gas and monosilane (SiH ₄ ) gas were respectively supplied, and a first tungsten nucleation layer was deposited in the aperture region and the upper portion of the insulating film by an atomic layer deposition method.

Next, tungsten fluoride (WF ₆ ) gas and monosilane (SiH ₄ ) gas were supplied respectively, and a first tungsten bulk layer was deposited on top of the first tungsten nucleation layer by a PECVD method.

Next, a second tungsten nucleation layer was deposited on the first tungsten bulk layer under the same deposition conditions as the first tungsten nucleation layer.

Then, ammonia gas was supplied as a deposition-suppressing gas and inductively coupled plasma was formed to form nitrogen radicals, which were used to pretreat the second tungsten nucleation layer.

In addition, the second tungsten nucleation layer, which was pretreated by supplying hydrogen gas as a reactive dose gas, was post-treated. At this time, the hydrogen gas was supplied at a flow rate of 500 sccm for 10 seconds to perform the post-treatment process.

Thereafter, a tungsten bulk layer (B) was formed on the post-processed second tungsten nucleation layer to form a tungsten thin film (NBNTDB) that gap-fills the opening area. The notation of the tungsten thin film (NBNTDB) indicates the state in which nucleation layer formation (N), bulk layer formation (B), nitrogen pretreatment, and reactive dose gas supply (T) were performed, respectively.

<Example 2>

A tungsten thin film (NBNTDB) was formed on the aperture area in the same manner as in Example 1, except that hydrogen gas was supplied at a flow rate of 1,500 sccm for 10 seconds for post-processing.

<Example 3>

A tungsten thin film (NBNTDB) was formed on the aperture area in the same manner as in Example 1, except that hydrogen gas was supplied at a flow rate of 3,000 sccm for 10 seconds for post-treatment.

<Example 4>

A tungsten thin film (NBNTDB) was formed on the aperture area in the same manner as in Example 1, except that post-treatment was performed by supplying tungsten hexafluoride gas as a reactive dose gas at a flow rate of 400 sccm for 10 seconds.

<Comparative Example 1>

A first tungsten nucleation layer (N) was formed on the opening region and the upper portion of the insulating film, and a first tungsten bulk layer (B) was formed on the first tungsten nucleation layer. Then, a second tungsten nucleation layer (N) was formed on the first tungsten bulk layer, and a second tungsten bulk layer (B) was formed on the second tungsten nucleation layer. In addition, a third tungsten nucleation layer (N) was formed on the second tungsten bulk layer, and a third tungsten bulk layer (B) was formed on the third tungsten nucleation layer. In addition, a fourth tungsten nucleation layer (N) was formed on the third tungsten bulk layer.

Next, a deposition-inhibiting gas was supplied onto the fourth tungsten nucleus formation layer to pretreat (T) the fourth tungsten nucleus formation layer. Thereafter, a tungsten bulk layer (B) was formed on the pretreated fourth tungsten nucleus formation layer to form a tungsten thin film (NBNBNBNTB) that gap-fills the opening area.

<Comparative Example 2>

A first tungsten nucleation layer (N) was formed on the aperture region and the upper portion of the insulating film, and a first tungsten bulk layer (B) was formed on the first tungsten nucleation layer. Then, a second tungsten nucleation layer (N) was formed on the first tungsten bulk layer, and hydrogen gas was supplied as a reactive dose gas so that only a post-treatment (D) of the second tungsten nucleation layer was performed without a pre-treatment. At this time, the hydrogen gas was supplied at a flow rate of 500 sccm for 10 seconds to perform the post-treatment process. Thereafter, a tungsten bulk layer was formed on the post-treated second tungsten nucleation layer, thereby forming a tungsten thin film (NBNDB) that gap-fills the aperture region.

<Comparative Example 3>

A tungsten thin film (NBNDB) was formed on the aperture area in the same manner as in Comparative Example 2, except that hydrogen gas was supplied at a flow rate of 1,500 sccm for 10 seconds each for post-processing (D).

<Comparative Example 4>

A tungsten thin film (NBNDB) was formed on the aperture area in the same manner as in Comparative Example 2, except that hydrogen gas was supplied at a flow rate of 3,000 sccm for 10 seconds each for post-processing (D).

<Comparative Example 5>

A tungsten thin film (NBNTB) was formed on the aperture area in the same manner as in Example 1, except that pretreatment (T) was performed with a deposition-inhibiting gas and post-treatment (D) of the tungsten nucleation layer with hydrogen gas, a reactive dose gas, was not performed.

<Comparative Example 6>

A first tungsten nucleation layer (N) was formed on the opening region and the upper portion of the insulating film, and a first tungsten bulk layer (B) was formed on the first tungsten nucleation layer. Then, a second tungsten nucleation layer (N) was formed on the first tungsten bulk layer, and a second tungsten bulk layer (B) was formed on the second tungsten nucleation layer, thereby forming a tungsten thin film (NBNB) gap-filling the opening region.

<Experimental example>

(1) Evaluation of membrane properties

The influence of post-processing conditions on film quality during thin film formation was evaluated by methods according to examples and comparative examples, and the results are shown in Table 1 and Fig. 2, respectively.

Post-processing conditions thickness Thickness range Surface resistance Surface resistance
Uniformity Growth thickness Comparative Example 1 - 4071.3 459.2 0.254 4.1 - Comparative Example 2 H2 500 sccm, 10 seconds 4083.2 164.4 0.253 3.9 - Comparative Example 3 H2 1500 sccm, 10 seconds 4094.7 160.1 0.251 3.8 - Comparative Example 4 H2 3000sccm, 10 seconds 4093.3 166.0 0.251 3.7 - Comparative Example 5 - 2657.2 279.6 0.454 3.4 1414.1 Example 1 H2 500 sccm, 10 seconds 2837.0 276.5 0.425 5.7 1246.0 Example 2 H2 1500 sccm, 10 seconds 3194.3 304.7 0.366 6.5 900.4 Example 3 H2 3000sccm, 10 seconds 3311.7 258.6 0,351 5.6 781.5

As shown in Table 1, the process of post-treating with a reactive dose gas does not affect the results of the conventional deposition process that is not pre-treated with a deposition-suppressing gas (Comparative Examples 1 to 4), but it was determined that it can be utilized as a step for optimizing the growth thickness in cases where pre-treating with a deposition-suppressing gas is performed (Examples 1 to 3). In particular, it was determined that the growth thickness of the tungsten bulk layer was greatly affected by the flow rate of the post-treatment gas compared to Comparative Example 5, and that the growth thickness can be controlled by the flow rate of the reactive dose gas.

In addition, it was confirmed that the surface resistance characteristics were improved by post-treatment compared to the tungsten thin film of Comparative Example 5 pre-treated with a deposition-inhibiting gas, and it was confirmed that the electrical characteristics for the deposition-inhibiting gas pre-treatment could be improved through such post-treatment.

In addition, it was confirmed that the incubation thickness can be quantitatively controlled by controlling the post-processing conditions including the flow rate of the reactive gas and the dose time.

Post-processing conditions thickness Thickness range Surface resistance Surface resistance
Uniformity Growth thickness Comparative Example 6 - 3719.7 144.2 0.301 2.6 - Comparative Example 5 - 2051.7 433.3 0.637 7.1 1668.0 Example 3 H2 3000sccm, 10 seconds 2702.3 330.3 0.456 6.8 1017.4 Example 2 H2 400 sccm, 10 seconds 2217.6 383.3 0.571 6.0 1502.1

As shown in Table 2, the effect of controlling the incubation thickness by supplying hydrogen gas and fluorine gas was confirmed. In particular, it was confirmed that the effect was universal and was not limited to a specific gas.

(2) Evaluation of the effect of hydrogen gas supply flow rate on growth thickness

The effect of the supply flow rate of hydrogen gas on the growth thickness of the tungsten bulk layer during the formation of a tungsten thin film was evaluated, and the results are shown in Fig. 7.

As shown in Fig. 7, it was confirmed that as the supply flow rate of hydrogen gas increased, the growth rate of the tungsten bulk layer was affected and the thickness gradually decreased. Based on this fact, it was judged that the deposition rate of the metal thin film inhibited with a nitrogen-containing deposition-inhibiting gas could be alleviated by the supply of the reactive dose gas, and that the growth rate (incubation rate), time (incubation time), and thickness (incubation thickness) of the metal bulk layer could be controlled by controlling the supply flow rate of the reactive dose gas.

By utilizing a technique of pretreating a metal nucleation layer or a metal bulk layer with a nitrogen-containing deposition suppressing gas and then posttreating the pretreated metal nucleation layer or the metal bulk layer with a reactive dose gas, a conductive material without a core can be embedded within an open area.

Claims (12)

A step of preparing a substrate including an insulating pattern defining an opening area; A step of forming a metal nucleation layer along the upper, side walls and bottom surface of the insulating pattern in which the opening region is formed; A step of pretreating the surface of the above metal nucleation layer with a nitrogen-containing deposition-inhibiting gas; and A step of forming a metal bulk layer on the above-mentioned pretreated metal nucleation layer; A method for forming a metal thin film, comprising a step of post-treating the pretreated metal nucleation layer with a reactive dose gas to control the deposition rate of the metal bulk layer prior to the step of forming the metal bulk layer. In the first paragraph, A method for forming a metal thin film, characterized in that the metal nucleation layer and the metal bulk layer each use at least one of tungsten (W), cobalt (Cu), ruthenium (Ru), and copper (Cu). In the first paragraph, A method for forming a metal thin film, wherein the above opening area is at least one of a trench and a hole. In the first paragraph, A method for forming a metal thin film, wherein the nitrogen-containing deposition-inhibiting gas includes at least one of ammonia (NH ₃ ) gas, amine (NH _X ) gas, nitrogen fluoride (NF ₃ ) gas, and nitrogen (N ₂ ) gas. In the first paragraph, A method for forming a metal thin film, characterized in that the reactive dose gas comprises at least one of a hydrogen-containing gas and a fluorine-containing gas. In the first paragraph, A method for forming a metal thin film, characterized in that the reactive dose gas includes at least one of hydrogen (H ₂ ) gas, ammonia (NH ₃ ) gas, silane (Si _X H _Y ) gas, and tungsten fluoride (WF ₆ ) gas. In the first paragraph, The step of supplying the above reactive dose gas is: A method for forming a metal thin film, characterized in that the reactive dose gas is supplied at a flow rate of 1 to 5,000 sccm and is performed under pressure conditions of 1 to 300 Torr. In the first paragraph, The step of supplying the above reactive dose gas is: A method for forming a metal thin film, characterized in that the method is performed by supplying the above reactive dose gas for 1 to 30 seconds. In the first paragraph, The step of forming the above metal nucleation layer is: A method for forming a metal thin film, characterized by supplying a metal precursor gas and a hydrogen-containing gas, respectively, and burying the metal nucleation layer inside the opening region by an atomic layer deposition (ALD) method. In the first paragraph, The step of forming the above metal bulk layer is: A method for forming a metal thin film, characterized in that a metal precursor gas and a hydrogen-containing gas are respectively supplied, and the metal bulk layer is formed using any one of a chemical vapor deposition method, a plasma-enhanced chemical vapor deposition method, an atomic layer deposition method, and a plasma-enhanced atomic layer deposition method. A step of preparing a substrate including an insulating pattern defining an opening area; A step of forming a metal nucleation layer along the surface of the insulating pattern with a limited opening area; A step of forming a first metal bulk layer on the above metal nucleation layer; A step of pretreating the first metal bulk layer with a nitrogen-containing deposition-suppressing gas; and A step of forming a second metal bulk layer on the first metal bulk layer that has been pretreated; including: A method for forming a metal thin film, comprising a step of post-treating the first metal bulk layer, which has been pretreated, with a reactive dose gas to control the deposition rate of the second metal bulk layer prior to the step of forming the second metal bulk layer. In Article 11, The step of forming the first metal bulk layer comprises: A method for forming a metal thin film, characterized in that the first metal bulk layer is formed to have a thickness of 10 to 30% of the entrance width of the hole.

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