METHOD FOR FORMING TiN THIN FILM

Abstract

According to an exemplary embodiment, a method for forming a barrier layer, which forms the barrier layer on a substrate by generating plasma, includes: spraying an ammonia-containing gas to adsorb onto the substrate; after the spraying of the ammonia-containing gas stops, spraying a purge gas onto the substrate for initial purging; generating plasma using a hydrogen gas; spraying a titanium-containing gas onto the substrate to form a titanium nitride thin film on the substrate; and after the spraying of the titanium-containing gas stops, spraying a purge gas onto the substrate for a second purging, and the method forms a process cycle, sequentially performing spraying of the ammonia-containing gas, initial purging, generating plasma, spraying of the titanium-containing gas, and second purging. According to an exemplary embodiment, the barrier layer made of titanium nitride thin film can be formed at low temperature by atomic layer deposition. Therefore, damage to the substrate or the thin film formed on the substrate due to high temperature can be prevented. Therefore, defects in devices containing the barrier layer can be prevented or the performance of devices containing the barrier layer can be improved. In addition, impurities on the barrier layer can be removed by hydrogen plasma. Therefore, degradation of the device or barrier layer quality caused by impurities can be prevented.

Description

[Technical Field]

[0001] This disclosure relates to a method for forming a barrier layer, and more particularly to a method for forming a barrier layer at low temperature by atomic layer deposition. [Previous Technology]

[0002] Each integrated circuit device, capacitor device, and the like includes a barrier layer formed between the dielectric layer and the conductive layer. Furthermore, the barrier layer is formed from a titanium nitride thin film using an atomic deposition method. Here, the deposition process is performed inside the cavity where the process is carried out or on the substrate to which the titanium nitride thin film is deposited, while maintaining a high temperature of 350°C or above. That is, a titanium nitride thin film can be deposited on the substrate while the inside of the cavity or the substrate is maintained at a high temperature of 350°C or above.

[0003] However, when titanium nitride films are formed at high temperatures, the substrate or the film formed on the substrate may be damaged by heat. In addition, this causes a reduction in the quality or performance of the device.

[0004] [Related Technical Documents]

[0005] [Patent Documents]

[0006] (Patent Document 1) Korean Patent Registration No. 10-0323268 [Summary of the Invention]

[0007] This disclosure provides a method for forming a barrier layer, which forms a barrier layer made of titanium nitride thin film by atomic layer deposition.

[0008] According to an exemplary embodiment, a method for forming a barrier layer by generating plasma to form a barrier layer on a substrate includes: spraying an ammonia-containing gas to adsorb onto the substrate; after the spraying of the ammonia-containing gas stops, spraying a purge gas onto the substrate for initial purging; generating plasma using hydrogen gas; spraying a titanium-containing gas onto the substrate to form a titanium nitride film on the substrate; and after the spraying of the titanium-containing gas stops, spraying a purge gas onto the substrate for a second purging, and the method forms a process cycle, sequentially performing spraying of ammonia-containing gas, initial purging, generating plasma, spraying of titanium-containing gas, and second purging.

[0009] The process cycle can be repeated.

[0010] According to another exemplary embodiment, the method of forming a barrier layer includes: spraying a titanium-containing gas into a processing space where a substrate is disposed; spraying an ammonia-containing gas into the processing space and generating plasma using the ammonia-containing gas; and spraying a hydrogen gas into the processing space and generating plasma using the hydrogen gas to remove impurities on the titanium nitride film.

[0011] The generation of plasma in each titanium nitride deposition and impurity removal may include supplying radio frequency power to a spraying unit for spraying ammonia-containing gas and hydrogen gas into the processing space, and this radio frequency power may be continuously supplied to the spraying unit from the deposition of the titanium nitride film to the removal of impurities.

[0012] The method may further include injecting purge gas into the treatment space between depositing the titanium nitride film and removing impurities.

[0013] Plasma can be generated by applying radio frequency power to the injection unit when the purging gas is injected.

[0014] The method may further include a pretreatment performed before the injection of titanium-containing gas, which may include: injecting ammonia-containing gas into the processing space to adsorb the ammonia-containing gas onto the substrate; injecting a purge gas into the processing space; and generating plasma using hydrogen gas.

[0015] The method may further include adjusting the temperature of each processing space and the support used to support the substrate in the processing space to be greater than or equal to 300°C and less than 350°C.

Implementation Method

[0017] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided instead to make this disclosure thorough and complete, and to fully convey the scope of the invention to those skilled in the art. In the drawings, for clarity, the dimensions and areas of the stacks are exaggerated. Similar reference numerals throughout refer to similar elements.

[0018] An exemplary embodiment relates to a method for forming a barrier layer made of a titanium nitride thin film. Specifically, an exemplary embodiment relates to a method for forming a barrier layer by depositing a titanium nitride thin film at a temperature less than 350°C. More specifically, an exemplary embodiment relates to a method for forming a barrier layer by depositing a titanium nitride thin film using atomic layer deposition (ALD) at a temperature greater than or equal to 300°C and less than 350°C.

[0019] Furthermore, the titanium nitride thin film formed by the method according to the exemplary embodiment can serve as a barrier layer disposed between the dielectric layer and the conductive layer to perform an insulating function. More specifically, the titanium nitride thin film according to the exemplary embodiment can serve as a barrier layer formed between the dielectric layer and the conductive layer in an integrated circuit device or a capacitor device.

[0020] FIG1 is a diagram illustrating a portion of an apparatus including a titanium nitride thin film formed according to the method of an exemplary embodiment. FIG2 is a conceptual diagram for explaining the method of forming a titanium nitride thin film according to the method of an exemplary embodiment. Here, FIG1 is a diagram illustrating a portion of an integrated circuit apparatus including a barrier layer disposed between a dielectric layer and a conductive layer, and illustrating a state in which the barrier layer is made of a titanium nitride thin film formed according to the method of an exemplary embodiment.

[0021] Referring to FIG1, an apparatus including a barrier layer 20 formed by the method according to an exemplary embodiment may include a substrate S, a dielectric layer 10 formed on the substrate S, a barrier layer 20 disposed on the dielectric layer 10 and made of a titanium nitride thin film, and a conductive layer 30 disposed on the barrier layer 20.

[0022] The substrate S may be a semiconductor substrate. Specifically, for example, the substrate may be a silicon wafer, a potassium arsenide wafer, or a silicon-germanium wafer.

[0023] A dielectric layer 10 is disposed on the substrate S. Here, the dielectric layer 10 may be made of a metal oxide. Specifically, the dielectric layer 10 may be formed, for example, of zirconium dioxide, aluminum oxide, titanium dioxide, tantalum dioxide, and hafnium dioxide. Furthermore, the dielectric layer 10 may be formed by atomic layer deposition or chemical vapor deposition.

[0024] The barrier layer 20 can be a stack formed on the dielectric layer 10 and made of a titanium nitride thin film. That is, the barrier layer 20 is formed after the dielectric layer 10 is formed on the substrate S and before the conductive layer 30 is formed, and is a stack made of a titanium nitride thin film. Here, the barrier layer 20 (i.e., the titanium nitride thin film) is formed by an atomic layer deposition method.

[0025] As described above, the titanium nitride thin film is formed between the dielectric layer 10 and the conductive layer 30, and the titanium nitride thin film serves as the barrier layer 20. Therefore, each titanium nitride thin film and the barrier layer can be represented by the same reference numeral "200". That is, the reference numeral "200" represents the titanium nitride thin film and the barrier layer.

[0026] When the barrier layer 20 is formed by atomic layer deposition, plasma is formed when the injection of the reactive gas stops or is completed. That is, when the injection of the reactive gas stops or is completed, plasma is generated using hydrogen.

[0027] Hereinafter, a method for forming a titanium nitride thin film or a barrier layer 20 made of a titanium nitride thin film by atomic layer deposition will be described with reference to FIG2. Herein, in FIG2, the term "on" indicates the feature of injecting gas and generating plasma, and the term "off" indicates the feature of stopping or completing the injection of gas or stopping the generation of plasma or a state in which no plasma is generated.

[0028] Referring to Figure 2, the formation of the titanium nitride thin film may include: injecting a source gas, stopping the injection of the source gas and then injecting a purge gas (initial purge), stopping the injection of the purge gas and then injecting a reaction gas, stopping the injection of the reaction gas and then injecting a purge gas (second purge), and stopping the injection of the purge gas and then forming a hydrogen plasma. Here, a titanium-containing gas can be used as the source gas, a nitrogen-containing gas can be used as the reaction gas, and argon can be used as the purge gas. Here, the titanium-containing gas may include titanium tetrachloride-containing gas, and the reaction gas may include ammonia-containing gas.

[0029] In an exemplary embodiment, the injection of the reactive gas generates plasma. That is, reactive gas plasma is generated because the reactive gas is emitted by applying radio frequency power when the reactive gas is injected.

[0030] Furthermore, hydrogen plasma is generated when the injection of the reactive gas stops or is completed. That is, hydrogen plasma (hydrogen plasma) is generated by injecting hydrogen gas after the injection of the reactive gas is completed and by applying radio frequency power to discharge the hydrogen gas. Here, the generation of hydrogen plasma can be carried out after the reactive gas is injected and the second purging is completed.

[0031] The above-described process of "injecting source gas - injecting purging gas (initial purging) - injecting reactive gas (generating plasma) - injecting purging gas (secondary purging) - generating hydrogen plasma" can form a process cycle for forming titanium nitride thin films. Furthermore, because the above process cycle is repeated multiple times, multiple atomic layer deposition methods are performed. Moreover, by adjusting the number of process cycles, titanium nitride thin films with a target thickness can be formed.

[0032] The process cycle described above, which includes "injecting source gas - injecting purging gas (initial purging) - injecting reactive gas (generating plasma) - injecting purging gas (second purging) - generating hydrogen plasma", involves injecting source gas again after the hydrogen plasma generation is completed. However, the exemplary embodiments are not limited thereto. For example, a purging gas injection (third purging) may be performed additionally after the hydrogen plasma generation. That is, "injecting source gas - injecting purging gas (initial purging) - injecting reactive gas (generating plasma) - injecting purging gas (second purging) - generating hydrogen plasma - injecting purging gas (third purging)" can form a process cycle for forming titanium nitride thin films.

[0033] In the above process cycle, when the source gas is injected, the source gas is adsorbed onto the dielectric layer. Furthermore, when plasma is generated by injecting a reactive gas after the initial purging (blowing out), the reactive gas (containing ammonia) adsorbed on the dielectric layer 10 and the source gas (titanium tetrachloride gas) react to generate a reactant, namely titanium nitride. This reactant accumulates or deposits on the dielectric layer 10, and thus a thin film made of titanium nitride is formed on the dielectric layer 10. That is, a barrier layer 20 made of the titanium nitride thin film is formed on the dielectric layer 10.

[0034] Typically, when forming a titanium nitride thin film using atomic layer deposition, the temperature of the processing space where the deposition process takes place (e.g., inside a cavity or on the substrate S where the titanium nitride thin film is deposited) is maintained at a high temperature of 350°C or higher. In other words, a titanium nitride thin film can only be deposited on the substrate S or the dielectric layer 10 when the cavity or the substrate S is maintained at a high temperature of 350°C or higher. However, when the titanium nitride thin film is formed at a high temperature as described above, the layers (e.g., the dielectric layer 10) formed under the substrate S or the titanium nitride thin film may be damaged by heat. Furthermore, this can cause a deterioration in the quality or performance of the device.

[0035] However, according to an exemplary embodiment, plasma is generated when forming a titanium nitride thin film or when depositing it by atomic layer deposition. That is, plasma is generated by applying radio frequency power during the jetting of reactive gases. The plasma generated during the jetting of reactive gases can improve the reaction efficiency of the source gas and the reactive gas and allow the reactants generated by the reaction between the source gas and the reactive gas to be easily deposited or attached to the substrate S or the dielectric layer 10. Therefore, a titanium nitride thin film can be formed by atomic layer deposition at a low temperature, for example, less than 350°C, inside the cavity or on the substrate. That is, a titanium nitride thin film can be formed at a low temperature, less than 350°C, instead of being formed when the substrate S is heated to a high temperature as in the related art. Therefore, the bottom support layer disposed under the substrate S or the titanium nitride thin film can be prevented from being damaged by high temperature.

[0036] Furthermore, hydrogen plasma is generated when the injection of the reactive gas stops. That is, hydrogen plasma is generated by injecting hydrogen gas and applying radio frequency power to the processing space to discharge hydrogen gas at the end of the injection of the reactive gas. The hydrogen plasma generated at this time can remove impurities. Here, impurities may be, for example, byproducts generated by the reaction between the source gas and the reactive gas. Specifically, impurities may be, for example, chlorine (impurities) generated by the reaction between titanium tetrachloride contained in the source gas and ammonia contained in the reactive gas. In addition, when hydrogen plasma is generated in the processing space, hydrogen gas (H2) reacts with impurities (e.g., chlorine) to form hydrogen chloride gas. In addition, hydrogen chloride gas is discharged to the outside through an exhaust section connected to the reaction space. Here, the plasma generated by the hydrogen gas promotes or accelerates the reaction between hydrogen gas and impurities (e.g., chlorine). Therefore, when hydrogen plasma is generated after the injection of reactive gas, impurities present in the processing space can be effectively removed. Therefore, it can prevent or suppress contamination caused by impurities when forming the titanium nitride thin film (i.e., barrier layer 20) and improve the efficiency of the device.

[0037] A conductive layer 30 is formed on the barrier layer (titanium nitride thin film) 200. Here, the conductive layer 30 can be made of a metal or a metal-containing material. For example, the conductive layer 30 can be made of at least one of copper, gold, silver, titanium, tantalum, cobalt, and platinum. Furthermore, the conductive layer 30 can be formed by atomic layer deposition or chemical vapor deposition.

[0038] The feature that the barrier layer 20 in the integrated circuit device is made of a titanium nitride thin film has been explained above. However, the exemplary embodiments are not limited to integrated circuit devices. For example, the inclusion of a barrier layer 20 made of a titanium nitride thin film can be applied to various devices that require a barrier layer 20, such as capacitor devices that include a barrier layer.

[0039] The method for forming a barrier layer according to the exemplary embodiment has a process cycle of "ejecting source gas - ejecting purging gas (primary purging) - ejecting reactive gas (generating plasma) - ejecting purging gas (secondary purging) - generating hydrogen plasma".

[0040] Here, the process cycle may include a pretreatment performed before the injection of hydrogen gas. Furthermore, the pretreatment may include the injection of reactive gas, the injection of purge gas after stopping the injection of reactive gas, and the generation of hydrogen plasma after stopping the injection of purge gas. Here, the reactive gas may be an ammonia-containing gas. That is, the pretreatment including the injection of reactive gas, the injection of purge gas (initial purging), and the generation of hydrogen plasma can be performed before a process cycle comprising "injection of source gas - injection of purge gas (initial purging) - injection of reactive gas (plasma generation) - injection of purge gas (secondary purging) - generation of hydrogen plasma".

[0041] Furthermore, pretreatment can only be performed before the initial process cycle, but not after the process cycle. That is, the process cycle is performed for the first time when the pretreatment is completed, and when the initial process cycle is completed, the injected source gas is cycled again instead of being pretreated again.

[0042] Figure 3 is a conceptual diagram for explaining a method of forming a titanium nitride thin film according to another exemplary embodiment.

[0043] A method for forming a titanium nitride thin film according to another exemplary embodiment is formed by an atomic layer deposition method and has a different sequence of injecting source gas and reactant gas. That is, as illustrated in FIG3, the method for forming a titanium nitride thin film according to another exemplary embodiment may include injecting reactant gas, injecting purge gas after stopping the injection of reactant gas (initial purge), generating hydrogen plasma after stopping the injection of purge gas, and injecting purge gas after stopping the generation of hydrogen plasma (second purge).

[0044] According to another exemplary embodiment, the generation of plasma can be omitted when the reactive gas is injected. Furthermore, after the injection of the reactive gas and the initial purging, hydrogen gas is injected to generate hydrogen plasma.

[0045] The above-mentioned "jet source gas - jet purging gas (primary purging) - generate hydrogen plasma - jet reaction gas - jet purging gas (secondary purging)" can form a process cycle for forming titanium nitride thin films.

[0046] The source gas, reactant gas, and purge gas may be the same as those described in the exemplary embodiments. That is, a titanium-containing gas may be used as the source gas, a nitrogen-containing gas may be used as the reactant gas, and argon may be used as the purge gas. Here, the titanium-containing gas may include titanium tetrachloride gas, and the reactant gas may include ammonia gas.

[0047] As described above, according to another exemplary embodiment, a reactive gas is injected before the injection of the source gas to generate a hydrogen plasma. When a hydrogen plasma is generated after the injection of the reactive gas, the film quality or deposition rate of the titanium nitride film can be improved. That is, when a hydrogen plasma is generated after the injection of the reactive gas, the ionization of the reactive gas can be enhanced. Therefore, the amount of free reactive gas adsorbed on the substrate S can be increased. Therefore, the amount of source gas reacting with the reactive gas adsorbed on the substrate S can be increased. Therefore, the deposition rate and film quality of the titanium nitride film can be improved.

[0048] FIG4 is a schematic diagram illustrating a deposition apparatus for forming a titanium nitride thin film or barrier layer according to an exemplary embodiment.

[0049] The deposition apparatus can deposit thin films by atomic layer deposition. As shown in FIG4, the deposition apparatus may include a chamber 100, a support member 200 mounted in the chamber 100 to support a substrate S, an injection unit 300 disposed facing the support member 200 and injecting process gas (hereinafter referred to as process gas) into the chamber 100, a gas supply unit 400 for supplying process gas to the injection unit 300, a first gas supply pipe 500a and a second gas supply pipe 500b connected to the injection unit 300 with different paths and supplying gas from the gas supply unit 400 to the injection unit 300, and an RF power unit 600 for applying RF power to generate plasma in the chamber 100.

[0050] In addition, the deposition apparatus may include a drive unit 700 for operating the support 200 to raise and rotate at least one of them, and an exhaust unit 800 connected to the chamber 100 to exhaust air from the interior of the chamber 100.

[0051] The chamber 100 may include an internal space on which a thin film is formed on a substrate S mounted within the chamber 100. For example, the internal space may have a rectangular, pentagonal, or hexagonal cross-sectional shape. Alternatively, the internal space of the chamber 100 may have various shapes depending on the shape of the substrate S.

[0052] The support member 200 may be disposed in the chamber 100 to face the spraying unit 300 and to support the substrate S loaded in the chamber 100. A heater 210 may be provided in the support member 200. Therefore, when the heater 210 is in operation, the substrate S disposed on the support member 200 and the interior of the chamber 100 may be heated.

[0053] In addition to the heater 210 provided in the support member 200, an independent heater may be provided outside or inside the chamber 100 as a heating substrate S or a unit inside the chamber 100.

[0054] The spraying unit 300 may include a first plate 310 disposed in the chamber 100 to face the support 200 and having a plurality of holes (hereinafter referred to as holes 311) that are separated from each other and arranged along the extension direction of the support 200, a plurality of nozzles 320 that are at least partially inserted into the plurality of holes 311, and a second plate 330 disposed in the chamber 100 between the first plate 310 and the upper wall.

[0055] In addition, the spraying unit 300 may further include an insulating portion 340 disposed between the first plate 310 and the second plate 330.

[0056] Herein, the first plate 310 can be connected to the radio frequency power unit 600, and the second plate 330 can be grounded. In addition, the insulating part 340 can be used to prevent electrical connection between the first plate 310 and the second plate 330.

[0057] The first plate 310 may have a plate-like shape extending along the extension direction of the support 200. Furthermore, when a plurality of holes 311 are defined in the first plate 310, each injection hole 311 may pass through the first plate 310 in a vertical direction. Additionally, the plurality of holes 311 may be arranged along the extension direction of the support 200 or the first plate 310.

[0058] Each nozzle 320 may have a shape extending in a vertical direction, with a passage for gas passage defined in each nozzle 320, and the upper and lower ends of each nozzle 320 are open. Furthermore, each nozzle 320 has at least a lower portion inserted into a hole 311 defined in the first plate 310 and a upper portion connected to the second plate 330. Therefore, each nozzle 320 may have a shape protruding downward from the second plate 330.

[0059] The nozzle 320 may have an outer diameter smaller than the inner diameter of the hole 311. Furthermore, when the nozzle 320 is inserted into the hole 311, the outer peripheral surface of the nozzle 320 may be separated from the peripheral wall of the hole 311 (i.e., the inner wall of the first plate 310). Therefore, the interior of the hole 311 may be divided into an external space and an internal space for the nozzle 320.

[0060] Within the internal space of the aperture 311, the internal space of the nozzle 320 serves as a passage for the gas supplied by the first gas supply pipe 500a to move and be ejected. Furthermore, within the internal space of the aperture 311, the external space of the nozzle 320 serves as a passage for the gas supplied by the second gas supply pipe 500b to move and be ejected. Therefore, hereinafter, the passage in the nozzle 320 is referred to as the first path 360a, and the external space of the nozzle 320 within the aperture 311 is referred to as the second path 360b.

[0061] The second plate 330 may have a top surface separate from the upper wall in the chamber 100 and a bottom surface separate from the first plate 310. Therefore, the empty space may be defined between the second plate 330 and the first plate 310 and between the second plate 330 and the upper wall in the chamber 100.

[0062] Herein, the upper space of the second plate 330 can be a space for the gas supplied by the first gas supply pipe 500a to diffuse and move, and is in communication with the upper openings of these nozzles 320 (hereinafter referred to as diffusion space 350). In other words, diffusion space 350 is connected to these first paths 360a. Therefore, the gas through the first gas supply pipe 500a can diffuse along the extension direction of the second plate 330 from the diffusion space 350, and then be injected downward through the plurality of first paths 360a.

[0063] Furthermore, a deep hole (gun drill) through which the gas moves can be defined in the second plate 330, and the deep hole can be connected to the second gas supply pipe 500b and communicate with the second path 360b. Therefore, the gas supplied by the second gas supply unit 500 can be injected into the substrate S through the deep hole and the second path 360b of the second plate 330.

[0064] The gas supply unit 400 provides the gas required for depositing a thin film in the atomic layer deposition method. The gas supply unit 400 may include: a source gas reservoir 410 for storing source gas, a reaction gas reservoir 420 for storing reaction gas that reacts with the source gas, a purge gas reservoir 430 for storing purge gas, a hydrogen gas reservoir 440 for storing hydrogen gas, a first transfer pipe 450a for connecting the source gas reservoir 410 to a first gas supply pipe 500a, and a second transfer pipe 450b for connecting a second gas supply pipe 500b to each of the reaction gas reservoir 420, the purge gas reservoir 430, and the hydrogen gas reservoir 440.

[0065] In addition, the gas supply unit 400 may include a connecting pipe 460 for connecting the second delivery pipe 450b to each of the reaction gas reservoir 420, the purging gas reservoir 430 and the hydrogen gas reservoir 440, and valves installed on each of the first delivery pipes 450a and the plurality of connecting pipes 460.

[0066] Hereinafter, a method for forming a barrier layer made of titanium nitride thin film according to an exemplary embodiment will be described with reference to FIGS. 1, 2 and 4. Here, a method for forming a barrier layer on a dielectric layer will be described by way of example.

[0067] First, the support member 200 is heated by operating the heater 210 provided in the support member 200. Here, the heater 210 is operated so that the support member 200 or the substrate S provided on the support member 200 has a temperature greater than or equal to 300°C and less than 350°C.

[0068] Thereafter, the substrate S on which the dielectric layer 10 is formed is loaded in the chamber 100 and disposed on the support member 200. Thereafter, when the substrate S disposed on the support member 200 has a target process temperature of 300°C, a barrier layer 20 made of titanium nitride thin film is formed on the dielectric layer 10.

[0069] Here, the barrier layer 20 is formed using an atomic layer deposition (ALD) method. Furthermore, the ALD method is performed in the following sequence: jetting a source gas, jetting a purge gas (initial purging), jetting a reactive gas, jetting a purge gas (secondary purging), and generating a hydrogen plasma, with the plasma generated during the jetting of the reactive gas. That is, the process cycle for forming the barrier layer 20 using the ALD method can be "jetting source gas - jetting purge gas (initial purging) - jetting reactive gas (generating plasma) - jetting purge gas (secondary purging) - generating hydrogen plasma". Furthermore, the process cycle is repeated multiple times to form a barrier layer 20 with a target thickness.

[0070] The following describes a method for injecting gas into the chamber 100 using the injection unit 300 and the gas supply unit 400 to form the barrier layer 20.

[0071] First, a source gas is injected into the chamber 100. For this purpose, titanium tetrachloride-containing gas stored in the source gas reservoir 410 is supplied to the first delivery pipe 450a. The source gas is introduced into the diffusion space 350 in the injection unit 300 through the first delivery pipe 450a and the first gas supply pipe 500a. Furthermore, the source gas diffuses in the diffusion space 350 and is then injected onto the substrate S through these nozzles 320 (i.e., these first paths 360a).

[0072] The injection of the source gas will stop after a preset time. Furthermore, after the injection of the source gas stops or is completed, purge gas will be supplied from the purge gas storage tank 430 and injected into the chamber 100 (initial purging). Here, the purge gas supplied from the purge gas storage tank 430 can pass through the connecting pipe 460, the second transmission pipe 450b, and the second gas transmission pipe 500b, and then be injected downwards through the second path 360b.

[0073] Subsequently, a reactive gas (e.g., ammonia-containing gas) is supplied from the reactive gas storage tank 420 and injected into the chamber 100. Here, the reactive gas and the purging gas can be injected into the chamber 100 through the same path. That is, the reactive gas can be injected downward through the connecting pipe 460, the second transmission pipe 450b, and the second gas transmission pipe 500b, and then through the second path 360b. When the reactive gas is injected, a reaction can occur between the reactive gas and the source gas adsorbed on the dielectric layer 10 to generate a reactant (i.e., a titanium nitride compound). Furthermore, this reactant accumulates or deposits on the dielectric layer 10, and thus forms a titanium nitride thin film on the substrate S.

[0074] When the reactive gas is injected into the chamber 100, the radio frequency power unit 600 is activated to apply radio frequency power to the first plate 310. As a result, plasma generated from the reactive gas is produced.

[0075] The plasma generated during the injection of the reactive gas can enhance the reaction efficiency between the source gas and the reactive gas, and allow the reactants generated by the reaction between the source gas and the reactive gas to be easily deposited or attached to the dielectric layer 10. In other words, although the substrate S or the interior of the chamber 100 heated by the heater 210 has a temperature of less than 350°C, the reaction between the reactive gas and the source gas can be easily carried out by the plasma generated during the injection of the reactive gas. Therefore, the titanium nitride film can be formed inside the chamber 100 or at a low temperature (e.g., less than 350°C) of the substrate S by atomic layer deposition. That is, the titanium nitride film can be formed at a low temperature of less than 350°C, rather than at a high temperature as in the related art. Therefore, the lower support layer placed under the substrate S or the titanium nitride film can be prevented from being damaged by high temperature.

[0076] After a preset time, the injection of the reaction gas will stop. Furthermore, when the injection of the reaction gas stops or is completed, purge gas is supplied from the purge gas reservoir 430 and injected into the chamber 100 (second purge). Here, the reactants generated from the reaction between the source gas and the reaction gas can be discharged outside the chamber 100 by the second purge.

[0077] When the second purging is completed, hydrogen gas is injected into chamber 100. Here, the hydrogen gas and the purging gas can be injected into chamber 100 through the same path. That is, the hydrogen gas can be injected downward through connecting pipe 460, second delivery pipe 450b and second gas delivery pipe 500b, and then through second path 360b. When the hydrogen gas is injected, the radio frequency power unit 600 is operated to apply radio frequency power to the first plate 310. As a result, plasma (i.e., hydrogen plasma) generated by the hydrogen gas is generated in chamber 100.

[0078] The hydrogen plasma generated at this time can remove residual impurities in the chamber 100. For example, chlorine (an impurity), a byproduct of the reaction between titanium tetrachloride contained in the source gas and ammonia contained in the reaction gas and remaining in the chamber 100 or on the titanium nitride film, reacts with hydrogen to produce hydrogen chloride. Here, the plasma generated by the hydrogen gas accelerates the reaction between hydrogen and chlorine. In addition, the hydrogen chloride gas is discharged through the exhaust portion connected to the chamber. Therefore, contamination caused by impurities during the formation of the titanium nitride film (i.e., the barrier layer 20) can be prevented or suppressed, and the efficiency of the device can be improved.

[0079] The process cycle described above, "injecting source gas - injecting purging gas (initial purging) - injecting reactive gas (generating plasma) - injecting purging gas (second purging) - generating hydrogen plasma," can be repeated multiple times. Furthermore, the number of times the process cycle is executed can be determined based on the target thickness. Additionally, injecting purging gas (third purging) can be added between generating hydrogen plasma and injecting source gas.

[0080] Furthermore, as described above, the plasma is generated during the injection of the reactant gas and the injection of the hydrogen gas, and no plasma is generated during the second purging. However, exemplary embodiments are not limited thereto. For example, plasma can be generated during the second purging using a purge gas (i.e., argon (Ar)). In other words, radio frequency power can be continuously applied from the injection of the reactant gas to the injection of the hydrogen gas. Therefore, plasma can be continuously generated during the injection of the reactant gas, the injection of the purge gas (second purging), and the generation of hydrogen plasma.

[0081] When a titanium nitride barrier layer 20 with a target thickness is formed, a conductive layer 30 is formed on the barrier layer 20. Here, the conductive layer 30 can be formed by atomic layer deposition or chemical vapor deposition, and is made of one of copper, gold, silver, titanium, tantalum, cobalt and platinum or a material containing at least one of the above.

[0082] According to an exemplary embodiment, a titanium nitride thin film (i.e., titanium nitride barrier layer 20) can be formed at a low temperature of less than 350°C. Therefore, damage to the substrate or underlying layer where the titanium nitride thin film is formed can be prevented. Furthermore, impurities on the barrier layer can be removed by generating hydrogen plasma, thereby improving the quality of the barrier layer or the device.

[0083] According to an exemplary embodiment, a barrier layer made of titanium nitride thin film can be formed at low temperature by atomic layer deposition. Therefore, damage to the substrate or the thin film formed on the substrate due to high temperature can be prevented. Therefore, defects in the device including the barrier layer can be prevented or the performance of the device including the barrier layer can be improved.

[0084] Furthermore, impurities on the barrier layer can be removed by generating hydrogen plasma. Therefore, the deterioration of the device or barrier layer quality caused by impurities can be prevented.

[0085] Although exemplary embodiments have been described, it should be understood that the present invention should not be limited to these embodiments, and those skilled in the art can make various changes and modifications within the spirit and scope of the following claims. [Simplified Explanation of the Diagram]

[0016] Exemplary embodiments can be understood in more detail through the following description in conjunction with the accompanying drawings, in which: FIG1 is a diagram illustrating a portion of an apparatus comprising a titanium nitride thin film formed according to the method of an exemplary embodiment. FIG2 is a conceptual diagram for explaining the method of forming a titanium nitride thin film according to the method of an exemplary embodiment. FIG3 is a conceptual diagram for explaining the method of forming a titanium nitride thin film according to another exemplary embodiment. FIG4 is a schematic diagram illustrating a deposition apparatus for forming a titanium nitride thin film or barrier layer according to an exemplary embodiment.

Claims

1. A method for forming a titanium nitride thin film on a substrate disposed inside a chamber, the method comprising: injecting a titanium-containing gas into the chamber using an injection unit; and injecting an ammonia-containing gas into the chamber using the injection unit; wherein, In the ammonia-containing gas injection, a plasma is generated using the ammonia-containing gas. The method further includes a pretreatment performed before the titanium-containing gas injection, wherein the pretreatment includes: injecting the ammonia-containing gas into a processing space to adsorb the ammonia-containing gas onto the substrate; injecting a purge gas into the processing space; and generating a plasma using hydrogen. The injection unit includes: a first plate having a plurality of holes separated from each other and disposed inside the chamber; a second plate being mounted between an upper wall inside the chamber and the first plate; and a plurality of nozzles, each at least partially inserted into the holes to protrude to a lower side of the second plate.

2. The method as described in request item 1, wherein, In the generation of the plasma, radio frequency power is applied to the first plate to generate the plasma in the chamber.

3. The method of claim 1 further includes generating a plasma using hydrogen after the injection of the ammonia-containing gas has stopped.

4. The method of claim 3 further comprises injecting a purge gas between the injection of the ammonia-containing gas and the generation of the plasma using hydrogen.

5. The method of claim 1 further comprises injecting a purging gas between the injection of the titanium-containing gas and the injection of the ammonia-containing gas.

6. The method of any one of claims 1 to 5 further comprises adjusting the temperature inside the chamber and the temperature of a support member supporting the substrate inside the chamber to be greater than or equal to about 300°C and less than about 350°C.

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