WO2010001931A1 - Method for thin-film formation and apparatus for thin-film formation - Google Patents

Method for thin-film formation and apparatus for thin-film formation Download PDF

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Publication number
WO2010001931A1
WO2010001931A1 PCT/JP2009/062052 JP2009062052W WO2010001931A1 WO 2010001931 A1 WO2010001931 A1 WO 2010001931A1 JP 2009062052 W JP2009062052 W JP 2009062052W WO 2010001931 A1 WO2010001931 A1 WO 2010001931A1
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Prior art keywords
gas
titanium
film
forming
titanium nitride
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PCT/JP2009/062052
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French (fr)
Japanese (ja)
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健索 成嶋
英亮 山▲崎▼
正人 小堆
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東京エレクトロン株式会社
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Publication of WO2010001931A1 publication Critical patent/WO2010001931A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
    • H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
    • H01L21/76838—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors
    • H01L21/76877—Filling of holes, grooves or trenches, e.g. vias, with conductive material
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/34—Nitrides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
    • H01L21/283—Deposition of conductive or insulating materials for electrodes conducting electric current
    • H01L21/285—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation
    • H01L21/28506—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers
    • H01L21/28512—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers on semiconductor bodies comprising elements of Group IV of the Periodic System
    • H01L21/28518—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers on semiconductor bodies comprising elements of Group IV of the Periodic System the conductive layers comprising silicides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
    • H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
    • H01L21/76838—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors
    • H01L21/76841—Barrier, adhesion or liner layers
    • H01L21/76843—Barrier, adhesion or liner layers formed in openings in a dielectric
    • H01L21/76846—Layer combinations
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
    • H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
    • H01L21/76838—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors
    • H01L21/76841—Barrier, adhesion or liner layers
    • H01L21/76853—Barrier, adhesion or liner layers characterized by particular after-treatment steps
    • H01L21/76855—After-treatment introducing at least one additional element into the layer
    • H01L21/76856—After-treatment introducing at least one additional element into the layer by treatment in plasmas or gaseous environments, e.g. nitriding a refractory metal liner
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
    • H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
    • H01L21/76838—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors
    • H01L21/76841—Barrier, adhesion or liner layers
    • H01L21/76867—Barrier, adhesion or liner layers characterized by methods of formation other than PVD, CVD or deposition from a liquids

Definitions

  • the present invention relates to a thin film forming method and a film forming apparatus for forming a thin film such as a barrier layer on the surface of a semiconductor wafer such as a silicon substrate.
  • various processes such as a film formation process, an oxidation diffusion process, an etching process, and a modification process are repeatedly performed on a semiconductor wafer made of a silicon substrate or the like.
  • Recent semiconductor devices with higher integration and higher density have a so-called multilayer wiring structure composed of a plurality of wiring layers.
  • the contact hole for electrically connecting the silicon substrate and the wiring layer, or the upper wiring layer and the lower wiring layer are electrically connected.
  • a technique for embedding metal in via holes has become more important.
  • tungsten has a tendency to be buried mainly in a recess such as a contact hole or a via hole by a CVD (Chemical Vapor Deposition) method because of higher embedding performance.
  • CVD Chemical Vapor Deposition
  • FIG. 14 shows a general contact structure in a semiconductor wafer such as a silicon substrate embedded with tungsten.
  • a contact structure for example, first, in the insulating film 2 on the semiconductor wafer W made of a silicon substrate or the like, a region corresponding to the conductive layer 4 containing silicon. Is etched to form a recess 6 such as a hole.
  • the conductive layer 4 serves as an impurity diffusion layer that constitutes a lower wiring layer, a source and a drain of a transistor, and the like.
  • tungsten is buried in the recess 6.
  • the electrical characteristics of the recess 6, etc. the surface of the recess 6 is included prior to the formation of the tungsten film.
  • a titanium film 8 and a titanium nitride film 10 are sequentially formed on the entire wafer surface, and then a tungsten film 12 is formed thereon.
  • each of these film forming steps has been performed by a plurality of processing apparatuses.
  • the inside of the recess 6 is included by a plasma CVD method or the like using, for example, titanium tetrachloride (hereinafter also referred to as “TiCl 4 ”) gas and hydrogen (hereinafter also referred to as “H 2 ”) gas.
  • TiCl 4 titanium tetrachloride
  • H 2 hydrogen
  • the titanium film 8 is formed on the entire surface of the wafer W.
  • silicon in the conductive layer 4 reacts with titanium to form a titanium silicide (TiSix) layer 14.
  • the wafer W is transferred to the second processing apparatus, and the titanium nitride film 10 is formed by thermal CVD using, for example, titanium tetrachloride gas and ammonia (hereinafter also referred to as “NH 3 ”) gas. .
  • the wafer W is transferred to the third processing apparatus, and, for example, both monosilane (SiH 4 ) gas and hydrogen gas or one gas and tungsten hexafluoride (hereinafter also referred to as “WF 6 ”) gas are used.
  • the tungsten film 12 is formed by a thermal CVD method. As a result, tungsten is embedded in the recess 6.
  • the tungsten hexafluoride gas used when forming such a tungsten film 12 contains fluorine (F) having high reactivity with a metal such as titanium, the titanium nitride film 10 is not formed.
  • the titanium film 8 is etched by fluorine. That is, the titanium nitride film 10 formed between the tungsten film 12 and the titanium film 8 functions as a barrier layer that prevents the diffusion of fluorine in the process of forming the tungsten film 12. Is kept in a good state without being invaded by fluorine.
  • a titanium nitride film 10 has been conventionally formed on the titanium film 8.
  • the surface of the titanium film 8 is nitrided by, for example, plasma.
  • a thin titanium nitride layer 16 is formed on the surface (upper layer portion) of the titanium film 8, so that the titanium film 8 is used by the titanium tetrachloride gas used in the next film-forming process of the titanium nitride film 10 by, for example, the thermal CVD method. It is possible to prevent the surface of the substrate from being etched.
  • a method for forming such a titanium / titanium nitride laminated structure is described in, for example, Japanese Patent Application Laid-Open No. 2003-142425 and Japanese Patent Application Publication No. 2002-542399 (WO00 / 63959A1).
  • titanium layer 18 remains on the titanium film 8. Therefore, if the titanium nitride layer 16 and the titanium nitride film 10 of the titanium film 8 do not have sufficient thickness, a part of fluorine passes through the titanium nitride layer 10 and the titanium nitride film 16 and the titanium layer 18 of the titanium film 8. And fragile titanium fluoride (TiFx) may be generated. When titanium fluoride is generated in this way, the adhesion between the titanium nitride film 10 and the tungsten film 12 is deteriorated and may be peeled off from the surface of the wafer W.
  • TiFx fragile titanium fluoride
  • titanium nitride is formed by thermal CVD in the second processing apparatus.
  • this thermal CVD method has a relatively low directivity during film formation. Therefore, as shown in FIG. 14B, not only the bottom in the recess 6 but also the side wall of the recess 6 is formed.
  • the titanium nitride film 10 is isotropically deposited also in a portion corresponding to 6A, and as a result, the inside of the recess 6 becomes too narrow, and the film forming gas is increased in the subsequent tungsten film forming process.
  • the plug resistance could not be sufficiently penetrated into the recess 6 and the amount of embedding of the recess 6 was reduced to increase the plug resistance.
  • the present invention is a film forming technique for forming a thin film laminated structure (which can function as, for example, a barrier layer) in a recess of an object to be processed, which includes two titanium nitride films not including a titanium layer. Is to provide.
  • the present invention is capable of efficiently depositing the titanium nitride film on the bottom of the recess while suppressing the deposition on the sidewall of the recess even when the recess has a small diameter. It also provides membrane technology.
  • the present invention provides a film forming method for forming a thin film on a surface of an object to be processed having a recess formed on the surface, wherein the first titanium nitride film is formed on the surface of the object to be processed including the inner surface of the recess.
  • a titanium film forming step of forming a titanium film on the surface of the object including the inner surface of the recess using a titanium compound gas and a reducing gas, and a titanium film forming step using a nitriding gas Performing a nitriding step of nitriding all of the titanium film formed by the step of forming a titanium nitride film in this order at least once, and forming the first titanium nitride film, And a step of forming a second titanium nitride film by a titanium nitride film deposition step formed by depositing a second titanium nitride film on the titanium nitride film.
  • the step of forming the first titanium nitride film can be executed by alternately repeating the titanium film forming step and the nitriding step a plurality of times.
  • the titanium film forming step and the nitriding step can be performed in the presence of plasma, respectively.
  • a conductive layer containing silicon may be exposed at the bottom of the recess.
  • silicon in the conductive layer reacts with titanium in the titanium film to form a titanium silicide layer.
  • the object to be processed can be set to the first temperature. This first temperature may be in the range of 400-650 ° C.
  • the film thickness of the first titanium nitride film formed in the step of forming the first titanium nitride film can be 15 nm or less.
  • the second titanium nitride film may be deposited in the presence of plasma using a titanium compound gas, a reducing gas, a nitrogen gas, and a plasma stabilizing gas.
  • the predetermined relational expression can be expressed by the following mathematical formula 1 when the flow rate of the titanium compound gas is 20 sccm or less.
  • the lower limit of the flow rate Y 1 of the nitrogen gas is preferably 1 sccm.
  • the flow rate Y 2 and the high-frequency power X 2 can be set so as to satisfy a predetermined relational expression determined depending on the flow rate of gas per unit area of the object to be processed.
  • the predetermined relational expression can be expressed by the following mathematical expression 2 when the flow rate of the titanium compound gas per unit area of the object to be processed is 2.831 ⁇ 10 ⁇ 2 sccm / cm 2 or less.
  • the lower limit of the flow rate Y 2 of nitrogen gas per unit area of the object to be processed is preferably 1.415 ⁇ 10 ⁇ 3 sccm / cm 2 .
  • the relationship between the partial pressure Y 3 of the nitrogen gas and the high-frequency power X 3 per unit area of the object to be processed to generate plasma is determined depending on the partial pressure of the titanium compound gas. It can be set as the partial pressure Y 3 so as to satisfy a predetermined relational expression and the high frequency power X 3.
  • the predetermined relational expression can be expressed by the following mathematical formula 3 when the partial pressure of the titanium compound gas is 2.37 Pa or less. Y 3 ⁇ 28.9 ⁇ 10 1 ⁇ X 3 2 ⁇ 140 ⁇ X 3 + 1.87 ⁇ 10 2 ... (Formula 3)
  • partial lower limit of the pressure Y 3 of the nitrogen gas is preferably 0.12 Pa.
  • the titanium film forming step, the nitriding step, and the titanium nitride film depositing step are performed in the same film forming apparatus, and according to this, the number of film forming apparatuses required is reduced. This can be reduced and can contribute to the reduction of the equipment cost.
  • the titanium compound gas can be titanium tetrachloride gas.
  • the reducing gas can be H 2 gas.
  • tungsten film forming step of forming a tungsten film on the second titanium nitride film and filling the recess.
  • the present invention provides a film forming apparatus for forming a thin film on a surface of an object to be processed in which a recess is formed on the surface, a processing container for accommodating the object to be processed, and the object to be processed in the processing container.
  • a mounting table provided with a lower electrode, a shower head unit that introduces gas into the processing vessel and also serves as an upper electrode, and a gas supply that supplies the necessary gas connected to the shower head unit Means, heating means for heating the object to be processed, an exhaust system for evacuating the inside of the processing container, high-frequency power supply means for supplying high-frequency power to form plasma in the processing container,
  • a film forming apparatus including a control unit that controls the entire apparatus so as to perform a thin film forming method.
  • the present invention provides a processing container that accommodates an object to be processed, a mounting table on which the object to be processed is mounted in the processing container and provided with a lower electrode, a gas that is introduced into the processing container and an upper part shower head part also used as an electrode, gas supply means connected to the shower head part for supplying necessary gas, heating means for heating the object to be processed, and exhaust system for evacuating the inside of the processing vessel
  • a concave portion is formed on the surface using a film forming apparatus comprising: a high-frequency power supply means for supplying high-frequency power to form plasma in the processing container; and a control unit for controlling the entire apparatus.
  • RF power constant RF power
  • FIG. 6 is a graph for explaining the influence of the N 2 gas flow rate, the RF power, and the TiCl 4 gas flow rate on the change in film thickness peak when the second titanium nitride film is formed. It is a graph for explaining the optimum range of the N 2 gas flow rate to the high-frequency power at the time of depositing the second titanium nitride film. It is a graph for explaining the optimum range of the N 2 gas flow rate per unit area of the object with respect to the high frequency power per unit area of the object at the time of depositing the second titanium nitride film. It is a graph for explaining the optimum range of the partial pressure of N 2 gas to the high frequency power per unit area of the object at the time of depositing the second titanium nitride film.
  • RF power is 800 W
  • the film forming apparatus 22 has a processing container 24 made of aluminum or aluminum alloy, the inside of which is substantially cylindrical.
  • a susceptor 26 as a mounting table for horizontally supporting a semiconductor wafer W as an object to be processed is supported by a cylindrical support member 28 provided at the lower center thereof. Is arranged in.
  • the susceptor 26 is made of a ceramic such as aluminum nitride (AlN), and a guide ring 30 for guiding the wafer W is provided on the outer edge thereof.
  • a heater 32 is embedded in the susceptor 26 as a heating means for heating the wafer W, and the heater 32 is heated by the heater power supply 34 to heat the wafer W to a predetermined temperature.
  • a lower electrode 36 is embedded on the heater 32, and the lower electrode 36 is grounded (not shown), for example.
  • the shower head section 40 is provided on the top wall 24A of the processing container 24 via an insulating member 38.
  • the shower head portion 40 is roughly composed of a base member 42 as an upper portion and a shower plate 44 as a lower portion.
  • a heater 46 is embedded in the base member 42, and the heater 46 can be heated to a predetermined temperature by being supplied with power from a heater power supply 48.
  • the shower plate 44 is formed with a number of discharge holes 50 for discharging gas into the processing vessel 24. Each discharge hole 50 communicates with a gas diffusion space 52 formed between the base member 42 and the shower plate 44.
  • a gas introduction port 54 for supplying a processing gas to the gas diffusion space 52 is provided at the center of the base member 42. The gas introduction port 54 is connected to a mixed gas supply line 58 of a gas supply means 56 described later.
  • the gas supply means 56 includes, for example, a titanium tetrachloride gas supply source 60 that supplies titanium tetrachloride gas as a titanium compound gas, and an argon gas supply source 62 that supplies, for example, argon (hereinafter also referred to as “Ar”) gas as a plasma stabilizing gas.
  • a hydrogen gas supply source 64 for supplying hydrogen gas as a reducing gas, an ammonia gas supply source 66 for supplying ammonia gas as a nitrogen compound gas, and a nitrogen gas supply source 68 for supplying nitrogen gas are provided.
  • the titanium tetrachloride gas supply line 60L is connected to the titanium tetrachloride gas supply source 60, the argon gas supply line 62L is connected to the argon gas supply source 62, and the hydrogen gas supply source 64 is supplied with hydrogen.
  • a gas supply line 64L is connected, an ammonia gas supply line 66L is connected to the ammonia gas supply source 66, and a nitrogen gas supply line 68L is connected to the nitrogen gas supply source 68.
  • the gas supply lines 60L to 68L are respectively provided with mass flow controllers (MFC) 60C to 68C and two valves 60V to 68V across the mass flow controllers 60C to 68C.
  • MFC mass flow controllers
  • the ends of the lines 60L to 68L are connected to the gas mixing unit 70.
  • the gas mixing unit 70 has a function of mixing the processing gas and supplying it to the shower head unit 40.
  • the gas inflow side is connected to the gas inflow side via the gas supply lines 60L to 68L as described above.
  • the gas supply sources 60 to 68 are connected to each other, and the shower head unit 40 is connected to the gas outflow side via the mixed gas supply line 58.
  • one kind of gas selected from titanium tetrachloride gas, argon gas, hydrogen gas, ammonia gas and nitrogen gas or a mixed gas of a plurality of gases is introduced into the gas introduction port 54 of the shower head 40 and gas diffusion. It is introduced into the processing container 24 from the plurality of ejection holes 50 via the space 52.
  • the shower head unit 40 is configured as a so-called premix type in which each gas is mixed in advance and supplied into the processing container 24.
  • each gas is independently supplied into the processing container 24. You may make it comprise with what is called a postmix type supplied to.
  • the shower head unit 40 is connected to high frequency power supply means 72 for supplying high frequency power for generating plasma.
  • the high-frequency power supply means 72 has a power supply line 74 connected to the shower head unit 40, and a matching unit 76 and a high-frequency power supply 78 are sequentially interposed in the power supply line 74.
  • a high frequency electric field is generated between the shower head unit 40 also serving as the upper electrode and the lower electrode 36, and is generated in the processing container 24.
  • the supplied gas can be converted into plasma.
  • a circular hole is formed in the center of the bottom wall 24B of the processing container 24, and an exhaust chamber 80 that protrudes downward is provided on the bottom wall 24B so as to cover the hole.
  • An exhaust pipe 82 is connected to the side surface of the exhaust chamber 80, and an exhaust system 84 is connected to the exhaust pipe 82.
  • the exhaust system 84 has a pressure control valve and a vacuum pump (not shown), and performs vacuum exhaust as described above.
  • the susceptor 26 is provided with three wafer support pins 84 (only two are shown) for supporting the wafer W to be moved up and down so that the wafer support pins 84 can be raised and lowered with respect to the surface of the susceptor 26. It is fixed to the plate 86.
  • the wafer support pins 84 are moved up and down via a support plate 86 by a drive mechanism 88 such as an air cylinder.
  • the side wall 24C of the processing container 24 is provided with a loading / unloading port 90 for loading / unloading the wafer W to / from a common transfer chamber (not shown) and a gate valve 92 for opening / closing the loading / unloading port 90. Yes.
  • Control of the overall operation of the film forming apparatus 22 having such a configuration for example, control of starting and stopping the supply of various gases, flow control of each gas, temperature control of the wafer W, pressure control in the processing container 24, etc.
  • this is performed by the control unit 94 formed of a computer.
  • a computer-readable program necessary for this control is described in the storage medium 96.
  • the storage medium 96 includes a flexible disk, CD (Compact Disc), CD-ROM, hard disk, flash memory, DVD, or the like.
  • an unprocessed semiconductor wafer W is transferred into a processing container 24 from a common transfer chamber (not shown) of, for example, a cluster tool processing system via a gate valve 92 and a loading / unloading port 90 opened using a transfer arm. It is brought in.
  • the wafer W is transferred to the wafer support pin 84 side by raising the wafer support pin 84 provided on the susceptor 26, and the wafer support pin 84 is lowered after the transfer arm is moved backward.
  • the wafer W is placed on the susceptor 26.
  • the inside of the processing container 24 is evacuated in advance, and the processing container 24 is sealed by closing the gate valve 92.
  • the insulating layer 2 and the recess 6 are formed in advance on the surface of the semiconductor wafer W. Impurity diffusion such as a lower wiring layer and a source and drain of a transistor is formed at the bottom of the recess 6.
  • the conductive layer 4 serving as a layer is exposed.
  • the heater 32 disposed on the susceptor 26 is driven to raise the temperature of the wafer W on the susceptor 26 to a predetermined temperature and maintain that temperature.
  • necessary gases are flowed from the gas sources 60 to 68 of the gas supply means 56 while controlling the flow rate, and these gases are mixed in the gas mixing unit 70 and then mixed through the mixed gas supply line 58.
  • the gas is introduced into the gas diffusion chamber 52 of the shower head unit 40.
  • the mixed gas introduced into the gas diffusion chamber 52 diffuses in the gas diffusion chamber 52 in the plane direction and is supplied to the processing space S below the numerous discharge holes 50.
  • the high-frequency power supply means 72 is driven to apply high-frequency power between the upper electrode formed of the shower head unit 40 and the lower electrode 36 provided on the susceptor 26, thereby allowing the processing space S to be applied.
  • a plasma mainly composed of Ar gas is generated, and various processes described below are executed.
  • the film forming method of the present invention performed using the film forming apparatus 22 is a step of forming a first titanium nitride film on the surface of a semiconductor wafer that is an object to be processed including the inner surface of the concave portion. All of the titanium film formed by the titanium film forming step using the titanium compound gas and the reducing gas on the surface of the object including the inner surface of the substrate and the titanium film forming step using the nitriding gas. Performing a nitridation step of forming a titanium nitride film by nitriding at least once in this order, and forming a first titanium nitride film on the first titanium nitride film.
  • a step of forming a second titanium nitride film by a titanium nitride film deposition step formed by depositing a titanium nitride film is a step of forming a second titanium nitride film by a titanium nitride film deposition step formed by depositing a titanium nitride film.
  • “formation by deposition” means that the first titanium nitride film is formed by two independent processes (film formation (deposition) process of non-nitrided film and subsequent nitridation process) that can be clearly distinguished from each other.
  • the (second) titanium nitride film is deposited substantially in one step, typically directly by supplying a titanium compound gas and a nitriding gas simultaneously. This means that a titanium nitride film is deposited.
  • step S ⁇ b> 1 a titanium film forming process is performed in which a titanium film 100 is formed on the surface of the wafer W using a titanium compound gas and a reducing gas.
  • TiCl 4 gas is used as the titanium compound gas
  • H 2 gas is used as the reducing gas.
  • This titanium film forming step is performed by, for example, an SFD (Sequential Flow Deposition) method as described later. At this time, titanium is silicided at the boundary between the titanium film 100 and the conductive layer 4 to form a titanium silicide layer 102.
  • SFD Sequential Flow Deposition
  • step S ⁇ b> 2 a nitriding process is performed in which the titanium film 100 is entirely nitrided using a nitriding gas to form a first titanium nitride film 104.
  • a nitriding gas for example, NH 3 gas is used as the nitriding gas.
  • step S3 the titanium film forming process in step S1 and the nitriding process in step S2 are alternately repeated a predetermined number of times.
  • the number of repetitions may be “1” or a plurality of times, but the number of repetitions is zero, both steps S1 and S2 are performed only once (one pass), and the process proceeds to the next step S4. Good.
  • a second titanium nitride film 106 is deposited on the surface of the wafer W including the inner surface of the recess 6.
  • the second titanium nitride film 106 is formed in the presence of plasma using a titanium compound gas, a reducing gas, a nitriding gas, and a plasma stabilizing gas.
  • a barrier layer 108 composed of the first and second titanium nitride films 104 and 106 is formed.
  • a tungsten film forming step for forming the tungsten film 110 on the surface of the wafer W and burying the recess 6 is performed as shown in step S5.
  • ⁇ Titanium film forming process and nitriding process> First, a titanium film forming process and a nitriding process will be described.
  • the titanium film forming step and the nitriding step are alternately repeated a plurality of times.
  • a plasma SFD Sequential Flow
  • Deposition a plasma SFD (Sequential Flow) for forming the first titanium nitride film 104 by repeatedly forming the thin titanium film 100 and nitriding the thin titanium film 100 several times. Deposition) method can be used.
  • a titanium film is formed by generating plasma while supplying titanium compound gas, argon gas, and hydrogen gas at the same time to form a thin titanium film 100.
  • the process and the nitriding step of generating plasma while supplying ammonia gas, argon gas and hydrogen gas at the same time and nitriding all of the thin titanium film 100 are defined as one cycle, and this is the first titanium nitride film. Repeat several times until 104 reaches a predetermined film thickness.
  • the process temperature (wafer temperature) is set within the range of 400 to 650 ° C. (first temperature in the claims), more preferably within the range of 400 to 560 ° C., for example, 550 ° C., and the process pressure is set to For example, it is set within a range of 500 to 800 Pa, for example, 667 Pa.
  • P11 gas stabilization
  • titanium tetrachloride gas titanium compound gas
  • hydrogen gas reducing gas
  • argon gas argon gas
  • the flow rate of titanium tetrachloride gas is adjusted to, for example, 12 sccm
  • the flow rate of hydrogen gas is adjusted to, for example, 4000 sccm
  • the flow rate of argon gas is adjusted to, for example, 1600 sccm.
  • the main purpose of this period P11 is to stabilize the processing gas in the processing container 24 prior to the next period P12.
  • the period P11 is set to 0 to 5 seconds, for example.
  • a high frequency power of, for example, 800 W is applied to the shower head portion (upper electrode) 40 while titanium tetrachloride gas, hydrogen gas, and argon gas are continuously supplied from the period P11 at the same flow rate. And plasma is formed. Thereby, the titanium film 100 is deposited. Titanium in the titanium film 100 reacts with silicon at the boundary with the lower conductive layer 4 to be silicided.
  • the period P12 is set to 4 seconds, for example.
  • period P13 hydrogen gas and argon gas are supplied at the same flow rate as in period P12, and these are turned into plasma.
  • the titanium film 100 deposited in the previous period P12 is plasma annealed.
  • the period P13 is set to 5 seconds, for example.
  • This period P14 is a waiting time until the next period P15 is started, and this time is, for example, 1 second.
  • the period P15 all of the titanium film 100 formed by the treatment in the periods P11 to P14 is nitrided to form the very thin first titanium nitride film 104.
  • hydrogen gas, argon gas, and ammonia gas nitrogen compound gas
  • a high frequency power of, for example, 800 W is applied to the shower head (upper electrode) 40 to form plasma again.
  • the flow rate of hydrogen gas is adjusted to 2000 sccm
  • the flow rate of argon gas is adjusted to 1600 sccm, for example
  • the flow rate of ammonia gas is adjusted to 1500 sccm, for example.
  • the period P15 is set to 5 seconds, for example.
  • the plasma is turned off and the supply of ammonia gas is stopped.
  • the hydrogen gas and the argon gas are adjusted to the same flow rate as in the period P15, and the ammonia gas remaining in the processing container 24 is purged with these gases. This prevents the titanium tetrachloride gas supplied into the processing container 24 from being mixed with the residual ammonia gas in the period P11 of the next cycle, and forms a higher quality first titanium nitride film. Can do.
  • the period P16 is set to 2 seconds, for example.
  • Each process in the above periods P11 to P16 is set as one cycle, and the same cycle is repeated until the first titanium nitride film 104 reaches a predetermined film thickness of 1 to 15 nm, for example, 10 nm. In this way, as shown in FIG. 3C, the first titanium nitride 104 having a predetermined thickness is formed.
  • the plasma SFD method is used for film formation, but instead of this, Japanese Patent Application Laid-Open No. 2004-232080 (or US publication US2005233093A1 corresponding thereto) is incorporated herein by reference. 4), that is, a cycle consisting of P12 (titanium film formation) and P13 (plasma annealing) in FIG.
  • a method may be adopted in which a titanium film having a thickness of 10 nm is formed, and thereafter, the entire titanium film is nitrided by plasma by P15 (nitriding treatment) in FIG.
  • a second titanium nitride film 106 is formed.
  • the reason why the second titanium nitride film 106 is formed is that the film thickness of the first titanium nitride film 104 alone is not sufficient in barrier properties against fluorine gas components caused by tungsten hexafluoride used in a subsequent process.
  • the deposition rate of the plasma SFD method is very low, and thus the throughput is greatly reduced. For reasons.
  • the important point in the second titanium nitride film deposition step is to suppress the film formation on the side surface of the recess 6 and to the bottom surface of the recess 6 in order to secure a sufficient amount of tungsten embedded in the recess 6 in a later step. Whether to perform the film formation.
  • the thickness T1 of the side wall in the recess 6 is made as thin as possible, and the thickness T2 of the bottom is made as thick as possible. Necessary. In particular, when the hole diameter of the recess 6 becomes 60 nm or less due to a further miniaturization tendency, control of film formation on the surface in the recess 6 becomes important.
  • the above object is achieved by optimizing the flow rate of N 2 gas in the titanium nitride film deposition step.
  • a titanium compound gas, a reducing gas, a nitrogen gas, and a plasma stabilizing gas are used.
  • a TiCl 4 gas is used as the titanium compound gas
  • an H 2 gas is used as the reducing gas.
  • Ar gas is used as the plasma stabilizing gas.
  • the above four types of gases are simultaneously supplied into the processing vessel 24, and high frequency power is applied to the shower head unit 40 to generate plasma, thereby generating active species of each gas and generating recesses 6 in the wafer W.
  • a second titanium nitride film is formed on the entire wafer surface including the inner surface by plasma CVD.
  • film formation on the sidewall of the recess 6 is suppressed by controlling the flow rate of each gas, particularly the flow rate of N 2 gas, and also controlling the high-frequency power input for plasma formation.
  • the film formation on the bottom of the recess 6 is promoted.
  • a titanium nitride film is deposited also on the upper surface of the insulating layer 2 of the wafer W.
  • the present inventors have found that the film formation state of titanium nitride on the surface in the recess 6 largely depends on the gas flow rates of titanium tetrachloride and N 2 and the high-frequency power to be supplied, and optimize these. I am doing so.
  • plasma treatment particularly plasma CVD treatment is used, and the gas flow rates of titanium tetrachloride and N 2 and the high-frequency power to be input are appropriately controlled, so that the inside of the recess 6
  • the deposition on the bottom surface can be promoted while the deposition on the side surface of the substrate is suppressed.
  • the horizontal axis represents the N 2 gas flow rate
  • the vertical axis represents the film thickness.
  • the TiCl 4 gas is changed from 8 sccm to 20 sccm.
  • the RF power at this time is constant at 800 W (watts).
  • a processing vessel corresponding to a wafer diameter of 300 mm is used, and its volume is 706.5 cm 3 , and this point is the same in each graph described hereinafter.
  • the film thickness peak value is obtained at a certain N 2 gas flow rate.
  • the peak position moves in the left-right direction depending on the TiCl 4 gas flow rate.
  • the peak K1 is when the N 2 gas flow rate is about 100 sccm
  • the peak K2 is when the N 2 gas flow rate is about 200 sccm
  • the TiCl 4 gas flow rate is when peak K3 when the 16sccm the N 2 gas flow rate of about 380Sccm
  • peak K4 when the TiCl 4 gas flow 20sccm the N 2 gas flow rate respectively appear when about 400 sccm.
  • the deposition state in the region on the left side of each of the peaks K1 to K4 at each TiCl 4 gas flow rate is the region on the right side. It was very good compared with. That is, it has been found that in the region on the left side of each of the peaks K1 to K4, the deposition on the bottom surface can be promoted while the deposition on the side surface in the recess 6 is suppressed.
  • FIG. 6 the horizontal axis represents the N 2 gas flow rate
  • the vertical axis represents the film thickness
  • the RF power is varied from 400 W to 1200 W.
  • FIG. 6 (A) is shown a case of 20 sccm
  • FIG 6 (B) shows a case of 12 sccm
  • FIG. 6 (C) shows a case of 6 sccm.
  • the peaks of the curves of the RF powers 400 W, 800 W, and 1200 W in FIG. 6A are M1, M2, and M3, respectively, and the peaks of the curves of the RF powers 400 W, 800 W, and 1200 W in FIG. , N2, and N3, and the peaks of the curves of RF power 400W, 800W, and 1200W in FIG. 6C are O1, O2, and O3, respectively.
  • the horizontal axis represents high frequency power (RF power): X 1
  • the vertical axis represents N 2 gas flow rate: Y 1 .
  • RF power radio frequency power
  • X 1 high frequency power
  • Y 1 the vertical axis represents N 2 gas flow rate: Y 1 .
  • each peak M1 ⁇ M3 in FIG. 6, N1 ⁇ N3, O1 ⁇ O3 is plotted for each flow rate of the TiCl 4 gas, tables in three curves the flow rate different from the TiCl 4 gas Has been.
  • region with the favorable deposition state of the left side from each peak in FIG. 6 becomes an area
  • the flow rate Y 1 of the nitrogen gas, the relationship between the high-frequency power X 1 to be introduced to generate plasma, and the flow rate Y 1 so as to satisfy a predetermined relational expression determined depending on the flow rate of the titanium compound gas the high frequency power X 1 are set.
  • the lower limit of the high frequency power is 200 W, and if the high frequency power becomes smaller than this, it becomes difficult to stably form and maintain the plasma.
  • the lower limit of the flow rate of the TiCl 4 gas is 1 sccm, and if this flow rate is less than 1 sccm, it is substantially difficult to form a titanium nitride film.
  • the flow rate of the TiCl 4 gas is preferably set to 4 sccm or more.
  • the flow rate of the N 2 gas is much larger than that of the TiCl 4 gas, but the lower limit is 1 sccm, which is the same as that of the TiCl 4 gas in consideration of the composition of the deposited TiN film. Considering the film rate, it is preferable to set it to 4 sccm or more.
  • the region below the curve represented by the above formula 1 is the optimum range, and the high frequency power X 1 and the N 2 gas flow rate Y 1 are set so as to fall within this region.
  • TiCl 4 gas flow rate in the area indicated by the number 1 is determined when 12 sccm, and the TiCl 4 gas flow also includes the optimum range determined at the time of 6 sccm, in Equation 1
  • the region shown indicates the optimum range determined when the TiCl 4 gas flow rate is 20 sccm or less.
  • the region below the curve expressed by the above equation 1-2 is the optimum range, and the high frequency power X 1 and the N 2 gas flow rate Y 1 are set so as to fall within this region.
  • the region below the curve represented by the above Formula 1-3 is the optimum range, and the high frequency power X 1 and the N 2 gas flow rate Y 1 are set so as to fall within this region.
  • the high-frequency power X 1 and the N 2 gas flow rate Y 1 are respectively determined so as to correspond to the shaded area in FIG.
  • the process temperature at this time is, for example, in the range of about 400 to 650 ° C., more preferably in the range of about 450 to 550 ° C.
  • the process pressure is in the range of about 500 to 800 Pa, more preferably. Is in the range of about 500 to 700 Pa.
  • the optimum range is determined based on the whole process conditions of the film forming apparatus (the flow rate of TiCl 4 gas flowing as a whole), but the present invention is not limited to this, and the semiconductor that is the object to be processed It may be determined in terms of a value per unit area of the wafer W.
  • FIG. 8 is an explanatory diagram for explaining the optimum range of the N 2 gas flow rate per unit area of the object to be processed with respect to the high frequency power per unit area of the object to be processed when the second titanium nitride film is deposited. .
  • the horizontal axis represents the high-frequency power per unit area of the wafer
  • the vertical axis represents the N 2 gas flow rate per unit area of the wafer. That is, here the flow rate Y 2 per unit area of the object to be processed of the nitrogen gas, the relationship between the high-frequency power X 2 per unit area of the object to be processed to be introduced to form the plasma, the titanium compound
  • the flow rate Y 2 and the high-frequency power X 2 are set so as to satisfy a predetermined relational expression determined depending on the flow rate of the gas per unit area of the object to be processed.
  • the TiCl 4 gas flow rate per unit area of the wafer is 1.699 ⁇ 10 ⁇ 2 sccm / cm 2 (corresponding to 12 sccm) and 0.849 ⁇
  • the optimum range determined at 10 ⁇ 2 sccm / cm 2 (corresponding to 6 sccm) is also included, and the region represented by Formula 2 has a TiCl 4 gas flow rate of 2.831 ⁇ 10 ⁇ 2 sccm per unit area of the wafer. This indicates an optimum range determined when it is less than / cm 2 .
  • the lower limits of the N 2 gas flow rate and the TiCl 4 gas flow rate per unit area of the wafer are 1.415 ⁇ 10 ⁇ 3 sccm / cm 2 (corresponding to 1 sccm), preferably 5.662 ⁇ 10 ⁇ 3. sccm / cm 2 (corresponding to 4 sccm).
  • FIG. 8 shows a value converted into a value per unit area of the semiconductor wafer W
  • the present invention is not limited to this, and each gas may be determined by converting into a partial pressure.
  • FIG. 9 is an explanatory diagram for explaining an optimum range of the partial pressure of N 2 gas with respect to the high frequency power per unit area of the object to be processed when the second titanium nitride film is deposited.
  • the horizontal axis represents the high frequency power per unit area of the wafer
  • the vertical axis represents the N 2 gas partial pressure.
  • the Ar gas flow rate is 1600 sccm
  • the H 2 gas flow rate is 4000 sccm
  • the process pressure is 667 Pa. That is, here the partial pressure Y 3 of the nitrogen gas, the relationship between the high-frequency power X 3 per unit area of the object to be processed to be introduced in order to generate the plasma, depends on the partial pressure of the titanium compound gas and the partial pressure Y 3 so as to satisfy a predetermined relational expression determined Te and the high frequency power X 3 is set.
  • the optimum range determined when the partial pressure of TiCl 4 is 1.43 Pa (corresponding to 12 sccm) and 0.71 Pa (corresponding to 6 sccm) is included in the region represented by Equation 3.
  • the region represented by Equation 3 represents the optimum range determined when the partial pressure of TiCl 4 is 2.37 Pa or less.
  • the lower limit of each partial pressure of N 2 gas and TiCl 4 gas is 0.12 Pa (corresponding to 1 sccm), preferably 0.48 Pa (corresponding to 4 sccm).
  • FIG. 10 is a graph showing the relationship between the N 2 gas flow rate and the film thickness when the RF power is 800 W and the TiCl 4 gas flow rate is 12 sccm.
  • the N 2 gas flow rate is varied from 1 to 1000 sccm in various ways.
  • a second titanium nitride film is deposited. This graph is the same graph as the characteristic when the high-frequency power in FIG. Therefore, the process conditions are as follows: high-frequency power is 800 W, TiCl 4 gas flow rate is 12 sccm, process temperature is 550 ° C., and the diameter of the recess 6 is 60 nm.
  • the film thickness sequentially increases, and when the N 2 gas flow rate is about 300 sccm, the film thickness reaches the peak N2. As the N 2 gas flow rate is further increased, the film thickness gradually decreases.
  • the processing mode corresponding to the region on the right side from the peak N2 without including the peak N2 is referred to as mode 1
  • the processing mode including the peak N2 and corresponding to the region on the left side from the peak N2 is referred to as mode 2.
  • the region of mode 2 is a region where the second titanium nitride film is deposited well as described above.
  • FIG. 11 is an electron micrograph showing the deposition state of the thin film near the bottom of the recess.
  • FIG. 11A shows mode 1 (point A1)
  • FIG. 11B shows mode 2 (point A2).
  • FIG. 11A an enlarged photograph of the vicinity of the bottom surface of the concave portion is shown together with the lower portion of the photograph showing the cross section of the concave portion.
  • the deposition time is 70 sec in mode 1 and 28 sec in mode 2.
  • the thickness of the titanium nitride film (second titanium nitride film) deposited on the bottom surface of the recess is substantially zero although the deposition time is longer than that in mode 2.
  • the bottom coverage (the thickness of the titanium nitride deposited on the bottom surface of the recess with respect to the thickness of the titanium nitride deposited on the upper surface of the insulating layer) was 0%, and an undesirable result was obtained.
  • mode 2 although the deposition time is short, a titanium nitride film (second titanium nitride film) is sufficiently deposited on the bottom surface of the recess and the bottom coverage reaches about 30%, which is preferable. The result was obtained. In this mode 2, it is confirmed that the titanium nitride film is very thin and slightly deposited on the side wall in the recess. From this point, it is confirmed that the deposition state in mode 2 is good. I was able to.
  • second titanium nitride film second titanium nitride film
  • FIG. 12 is a diagram schematically showing the form of the reaction that occurs when the N 2 gas flow rate is high and low when depositing the second titanium nitride film.
  • mode 1 is indicated
  • mode 2 is indicated.
  • the state of the gas entering the recess is schematically shown.
  • TiClx adheres to the surface in the recess 6 of the wafer W as described above, but N *, H *, and NH * are relatively larger than TiClx. Even if H * and NH * ⁇ are consumed in the vicinity of the opening of the recess 6, they remain sufficiently and reach the bottom of the recess 6 sufficiently, and a TiN film is sufficiently deposited on the bottom surface of the recess 6. Will be able to.
  • FIG. 13 is a timing chart showing the supply timing of each gas when forming a tungsten film.
  • the wafer W is transferred to another tungsten film forming apparatus (not shown).
  • the tungsten film is formed in the same manner as the film forming apparatus shown in FIG. 1, and a separately provided thermal CVD apparatus or the like may be used.
  • a separately provided thermal CVD apparatus or the like may be used.
  • the wafer temperature (process temperature) at this time is adjusted to about 250 to 350 ° C., which is lower than the process temperature of about 400 to 450 ° C. in the conventional general thermal CVD process.
  • the process pressure is adjusted to about 100 to 1000 Pa.
  • tungsten hexafluoride gas is supplied into the thermal CVD apparatus.
  • the flow rate of tungsten hexafluoride gas is adjusted to 10 to 30 sccm.
  • argon gas or nitrogen gas is supplied as a carrier gas together with the tungsten hexafluoride gas.
  • the period P21 is set to 0.5 to 5 seconds, for example.
  • period P22 is a waiting time until the next period P23 is started, and this time is, for example, 0.5 to 3.0 seconds. In this period P22, it is preferable to continue supplying argon gas or nitrogen gas as a purge gas into the thermal CVD apparatus.
  • a period P23 monosilane gas is supplied.
  • the flow rate of the monosilane gas is adjusted to 50 to 100 sccm.
  • argon gas or nitrogen gas is supplied as a carrier gas together with the monosilane gas.
  • the period P23 is set to 0.5 to 5 seconds, for example.
  • disilane (Si 2 H 6 ) gas, diborane (B 2 H 6 ) gas, or the like can be used instead of the monosilane gas.
  • period P24 is a waiting time until the period P21 of the next cycle is started, and this time is, for example, 0.5 to 3.0 seconds. In this period P24, it is preferable to continue supplying argon gas or nitrogen gas as a purge gas into the thermal CVD apparatus.
  • An extremely thin tungsten film is formed by executing the processes in the above periods P21 to P24. Then, the processing in the periods P21 to P24 is set as one cycle, and the cycle is repeated until the tungsten film 110 (see FIG. 3E) reaches a predetermined film thickness and the recess 6 is filled with tungsten.
  • the tungsten film 110 is formed by alternately supplying the tungsten hexafluoride gas and the monosilane gas and laminating extremely thin tungsten films. Therefore, the tungsten film 110 with good characteristics can be formed even at a process temperature of 250 to 350 ° C. which is much lower than the process temperature of 400 to 450 ° C. in the conventional general thermal CVD process.
  • the amount of tungsten deposited in one cycle is extremely small as described above. Therefore, if a tungsten film having a thickness of 200 to 300 nm is formed, for example, a considerably long process time is required. As a result, the throughput decreases. Therefore, in order to prevent this reduction in throughput, a second tungsten film forming process capable of obtaining a high film forming rate may be performed after the above SFD tungsten film forming process.
  • the process temperature is raised to about 400 to 450 ° C., and the process pressure is adjusted to about 2000 to 20000 Pa.
  • the monosilane gas as the reducing gas is switched to hydrogen gas, and the hydrogen gas and tungsten hexafluoride gas are supplied simultaneously and continuously together with the carrier gas.
  • the flow rate of the hydrogen gas is set to about 300 to 3000 sccm, for example, and the flow rate of the tungsten hexafluoride gas is adjusted to about 30 to 300 sccm.
  • the tungsten film 110 can be formed at a high film formation rate, for example, 1000 to 5000 ⁇ / min.
  • the thin titanium film 100 is formed by the titanium film forming process, and is nitrided by the nitriding process, whereby the first film having a thickness of, for example, 10 nm is formed.
  • the titanium nitride film 104 is formed.
  • the titanium film 100 before nitriding is thin, all of the titanium film 100 can be securely nitrided without leaving a layer made of titanium.
  • the SFD method since the titanium film formed in each titanium film forming process is extremely thin, the titanium film can be completely nitrided more reliably.
  • the titanium film that may actively react with fluorine contained in the tungsten hexafluoride gas used to form the tungsten film 110 is formed under the first titanium nitride film 104. Therefore, the second titanium nitride film 106 and the tungsten film 110 can be prevented from being peeled off from these base layers.
  • the barrier function can be sufficiently exhibited, As a result, it is possible to prevent diffusion of tungsten hexafluoride used in the tungsten film forming process, which is a subsequent process, due to fluorine.
  • the relationship among the N 2 gas amount, the high frequency power for plasma generation, and the TiCl 4 gas amount is optimized. Even inside a recess (hole), a titanium nitride film can be sufficiently formed on the bottom surface side while suppressing film formation on the side wall in the recess, preventing the inside of the recess from being blocked. can do.
  • a tungsten film can be sufficiently deposited in the concave portion in a subsequent tungsten film forming step, and the contact resistance (plug resistance) and the like can be reduced.
  • the throughput can be improved since the titanium film forming step, the nitriding step, and the titanium nitride film depositing step are continuously performed in the same film forming apparatus, the throughput can be improved.
  • the present invention is not limited to this, and other rare gases such as He may be used.
  • the titanium film forming step, the nitriding step, and the titanium nitride film depositing step are continuously performed in the same film forming apparatus.
  • the present invention is not limited to this, and the titanium nitride film depositing step is performed. May be performed by another film forming apparatus provided separately.
  • the semiconductor wafer includes a silicon substrate and a compound semiconductor substrate such as GaAs, SiC, and GaN.
  • the film formation target of the film formation method of the present invention is not limited to these substrates, and may be a glass substrate or a ceramic substrate used for a liquid crystal display device.

Abstract

Disclosed is a method for thin-film formation that forms a thin film on a surface of an object (W) to be treated, the surface having a concave (6) formed thereon.  The method comprises a titanium film forming step of forming a first titanium nitride film on a surface of the object including the inner surface of the concave in such a manner that a titanium film (100) is formed on the surface of the object including the inner surface of the concave using a titanium compound gas and a reducing gas, a nitriding step of nitriding the whole titanium film formed in the titanium film forming step using a nitriding gas, a step of performing the above steps in the above order at least once to form a first titanium nitride film (104), and a step of forming a second titanium nitride film (106) by a titanium nitride film depositing step of depositing the second titanium nitride film (106) directly on the first titanium nitride film (104).

Description

薄膜の成膜方法及び成膜装置Thin film forming method and film forming apparatus
　本発明は、シリコン基板等の半導体ウエハの表面に、バリヤ層等の薄膜を形成するための薄膜の成膜方法及び成膜装置に関する。 The present invention relates to a thin film forming method and a film forming apparatus for forming a thin film such as a barrier layer on the surface of a semiconductor wafer such as a silicon substrate.
　一般に、ＩＣ等の半導体デバイスを形成するためには、シリコン基板等よりなる半導体ウエハに対して、成膜処理、酸化拡散処理、エッチング処理、改質処理等の各種の処理が繰り返し施される。 Generally, in order to form a semiconductor device such as an IC, various processes such as a film formation process, an oxidation diffusion process, an etching process, and a modification process are repeatedly performed on a semiconductor wafer made of a silicon substrate or the like.
　高集積化や高密度化が進んだ近年の半導体デバイスは、複数の配線層から成る、いわゆる多層配線構造を有している。このような半導体デバイスにおいては、良好な電気的特性を得るためにも、シリコン基板と配線層とを電気的に接続するためのコンタクトホールや上側配線層と下側配線層とを電気的に接続するためのビアホールに対する金属の埋め込み技術がより重要となってきている。特に近年では、埋め込み性能がより高いなどの理由から、コンタクトホールやビアホール等の凹部には、主としてＣＶＤ（Ｃｈｅｍｉｃａｌ Ｖａｐｏｒ Ｄｅｐｏｓｉｔｉｏｎ）法によってタングステンが埋め込まれる傾向にある。 Recent semiconductor devices with higher integration and higher density have a so-called multilayer wiring structure composed of a plurality of wiring layers. In such a semiconductor device, in order to obtain good electrical characteristics, the contact hole for electrically connecting the silicon substrate and the wiring layer, or the upper wiring layer and the lower wiring layer are electrically connected. In order to achieve this, a technique for embedding metal in via holes has become more important. Particularly in recent years, tungsten has a tendency to be buried mainly in a recess such as a contact hole or a via hole by a CVD (Chemical Vapor Deposition) method because of higher embedding performance.
　上記タングステンが埋め込まれたシリコン基板等の半導体ウエハにおける一般的なコンタクト構造を図１４に示す。図１４（Ａ）に示すように、このようなコンタクト構造を得るためには例えば、まずシリコン基板等よりなる半導体ウエハＷ上の絶縁膜２のうち、シリコンが含まれる導電層４に対応する領域をエッチングしてホール等の凹部６を形成する。この導電層４が下層の配線層やトランジスタのソースやドレイン等を構成する不純物拡散層となる。 FIG. 14 shows a general contact structure in a semiconductor wafer such as a silicon substrate embedded with tungsten. As shown in FIG. 14A, in order to obtain such a contact structure, for example, first, in the insulating film 2 on the semiconductor wafer W made of a silicon substrate or the like, a region corresponding to the conductive layer 4 containing silicon. Is etched to form a recess 6 such as a hole. The conductive layer 4 serves as an impurity diffusion layer that constitutes a lower wiring layer, a source and a drain of a transistor, and the like.
　そして、上記凹部６内にタングステンを埋め込むことになるが、この場合、タングステン膜の密着性や凹部６の電気的特性などを向上させるため、タングステン膜の成膜に先立って凹部６の表面を含むウエハ表面全体に、チタン膜８と窒化チタン膜１０とを順に形成してから、その上にタングステン膜１２を形成する。 Then, tungsten is buried in the recess 6. In this case, in order to improve the adhesion of the tungsten film, the electrical characteristics of the recess 6, etc., the surface of the recess 6 is included prior to the formation of the tungsten film. A titanium film 8 and a titanium nitride film 10 are sequentially formed on the entire wafer surface, and then a tungsten film 12 is formed thereon.
　従来、これらの各成膜工程は、複数の処理装置で行うようになっていた。例えば先ず、第１の処理装置で例えば四塩化チタン（以下「ＴｉＣｌ４」とも称す）ガスと水素（以下「Ｈ２」とも称す）ガスとを用いてプラズマＣＶＤ法等により、凹部６内を含めてウエハＷの表面全体にチタン膜８を形成する。このとき、導電層４の表面には、導電層４中のシリコンとチタンとが反応してチタンシリサイド（ＴｉＳｉｘ）層１４が形成される。 Conventionally, each of these film forming steps has been performed by a plurality of processing apparatuses. For example, first, in the first processing apparatus, the inside of the recess 6 is included by a plasma CVD method or the like using, for example, titanium tetrachloride (hereinafter also referred to as “TiCl 4 ”) gas and hydrogen (hereinafter also referred to as “H 2 ”) gas. Thus, the titanium film 8 is formed on the entire surface of the wafer W. At this time, on the surface of the conductive layer 4, silicon in the conductive layer 4 reacts with titanium to form a titanium silicide (TiSix) layer 14.
　続いて、このウエハＷを第２の処理装置へ搬送して、例えば四塩化チタンガスとアンモニア（以下「ＮＨ３」とも称す）ガスとを用いて熱ＣＶＤ法により、窒化チタン膜１０を形成する。そして、このウエハＷを第３の処理装置へ搬送して、例えばモノシラン（ＳｉＨ４）ガスと水素ガスとの両方又は一方のガスと六フッ化タングステン（以下「ＷＦ６」とも称す）ガスを用いて熱ＣＶＤ法によりタングステン膜１２を形成する。これによって、凹部６内にはタングステンが埋め込まれる。 Subsequently, the wafer W is transferred to the second processing apparatus, and the titanium nitride film 10 is formed by thermal CVD using, for example, titanium tetrachloride gas and ammonia (hereinafter also referred to as “NH 3 ”) gas. . Then, the wafer W is transferred to the third processing apparatus, and, for example, both monosilane (SiH 4 ) gas and hydrogen gas or one gas and tungsten hexafluoride (hereinafter also referred to as “WF 6 ”) gas are used. Then, the tungsten film 12 is formed by a thermal CVD method. As a result, tungsten is embedded in the recess 6.
　このようなタングステン膜１２を形成する際に用いられる六フッ化タングステンガスは、チタンなどの金属と高い反応性を示すフッ素（Ｆ）を含むため、もし窒化チタン膜１０を形成せずに、チタン膜８上に直接的にタングステン膜１２を形成すると、このチタン膜８がフッ素によりエッチングされてしまう。つまり、タングステン膜１２とチタン膜８との間に形成される窒化チタン膜１０は、タングステン膜１２の形成工程におけるフッ素の拡散を防止するバリヤ層として機能するものであり、これによって、チタン膜８はフッ素の侵入を受けることなく良好な状態に保たれる。 Since the tungsten hexafluoride gas used when forming such a tungsten film 12 contains fluorine (F) having high reactivity with a metal such as titanium, the titanium nitride film 10 is not formed. When the tungsten film 12 is formed directly on the film 8, the titanium film 8 is etched by fluorine. That is, the titanium nitride film 10 formed between the tungsten film 12 and the titanium film 8 functions as a barrier layer that prevents the diffusion of fluorine in the process of forming the tungsten film 12. Is kept in a good state without being invaded by fluorine.
　このような理由により、従来、チタン膜８上には窒化チタン膜１０を形成していた。この場合、チタン膜８を形成した後、窒化チタン膜１０を形成する前に、チタン膜８の表面を例えばプラズマにより窒化する処理を行っていた。これにより、チタン膜８表面（上層部）に薄い窒化チタン層１６が形成されるため、次の例えば熱ＣＶＤ法による窒化チタン膜１０の成膜工程で使用される四塩化チタンガスによってチタン膜８の表面がエッチングされてしまうことを防止できる。このようなチタン／窒化チタン積層構造を形成する方法は、例えば、特開２００３－１４２４２５号公報、特表２００２－５４２３９９号公報（ＷＯ００／６３９５９Ａ１）に記載されている。 For this reason, a titanium nitride film 10 has been conventionally formed on the titanium film 8. In this case, after the titanium film 8 is formed and before the titanium nitride film 10 is formed, the surface of the titanium film 8 is nitrided by, for example, plasma. As a result, a thin titanium nitride layer 16 is formed on the surface (upper layer portion) of the titanium film 8, so that the titanium film 8 is used by the titanium tetrachloride gas used in the next film-forming process of the titanium nitride film 10 by, for example, the thermal CVD method. It is possible to prevent the surface of the substrate from being etched. A method for forming such a titanium / titanium nitride laminated structure is described in, for example, Japanese Patent Application Laid-Open No. 2003-142425 and Japanese Patent Application Publication No. 2002-542399 (WO00 / 63959A1).
　しかしながら、従来、チタン膜８の表面のみを窒化するので、チタン膜８にはチタン層１８が残っていた。このため、チタン膜８の窒化チタン層１６及び窒化チタン膜１０に十分な膜厚がなければ、フッ素の一部が窒化チタン層１０及び窒化チタン膜１６を通過してチタン膜８のチタン層１８に達してしまい、脆弱なフッ化チタン（ＴｉＦｘ）が生成される可能性があった。このようにフッ化チタンが生成されると、窒化チタン膜１０とタングステン膜１２は、下地層との密着性が劣化し、ウエハＷの表面から剥離する恐れがある。 However, conventionally, since only the surface of the titanium film 8 is nitrided, the titanium layer 18 remains on the titanium film 8. Therefore, if the titanium nitride layer 16 and the titanium nitride film 10 of the titanium film 8 do not have sufficient thickness, a part of fluorine passes through the titanium nitride layer 10 and the titanium nitride film 16 and the titanium layer 18 of the titanium film 8. And fragile titanium fluoride (TiFx) may be generated. When titanium fluoride is generated in this way, the adhesion between the titanium nitride film 10 and the tungsten film 12 is deteriorated and may be peeled off from the surface of the wafer W.
　また、微細化の要求が最近にあっては更に厳しくなり、上記凹部６の直径である例えばホール径の要求が６０ｎｍ、或いはそれ以下になると、上記第２の処理装置で熱ＣＶＤ法により窒化チタン膜１０を成膜する際、この熱ＣＶＤ法は成膜時の指向性が比較的小さいことから、図１４（Ｂ）に示すように上記凹部６内の底部は勿論のこと、凹部６の側壁６Ａに対応する部分にも比較的厚く窒化チタン膜１０が等方的に堆積してしまい、この結果、凹部６内が狭くなり過ぎて後工程のタングステン成膜工程時において、成膜ガスが上記凹部６内に十分に侵入できず、凹部６の埋め込み量の減少が発生してプラグ抵抗が増加する、といった問題もあった。 Further, recently, the demand for miniaturization becomes more severe, and when the demand for the diameter of the concave portion 6, for example, the hole diameter is 60 nm or less, titanium nitride is formed by thermal CVD in the second processing apparatus. When the film 10 is formed, this thermal CVD method has a relatively low directivity during film formation. Therefore, as shown in FIG. 14B, not only the bottom in the recess 6 but also the side wall of the recess 6 is formed. As a result, the titanium nitride film 10 is isotropically deposited also in a portion corresponding to 6A, and as a result, the inside of the recess 6 becomes too narrow, and the film forming gas is increased in the subsequent tungsten film forming process. There was also a problem in that the plug resistance could not be sufficiently penetrated into the recess 6 and the amount of embedding of the recess 6 was reduced to increase the plug resistance.
　本発明は、全体的には、チタン層を含まない２つの窒化チタン膜からなる薄膜積層構造（これは例えばバリヤ層として機能することができる）を被処理体の凹部内に形成する成膜技術を提供するものである。また本発明は、上記の窒化チタン膜を、被処理体の凹部の径が小さくても、凹部の側壁へ堆積することを抑制しつつ、凹部の底部に効率的に堆積させることが可能な成膜技術をも提供するものである。 In general, the present invention is a film forming technique for forming a thin film laminated structure (which can function as, for example, a barrier layer) in a recess of an object to be processed, which includes two titanium nitride films not including a titanium layer. Is to provide. In addition, the present invention is capable of efficiently depositing the titanium nitride film on the bottom of the recess while suppressing the deposition on the sidewall of the recess even when the recess has a small diameter. It also provides membrane technology.
　すなわち、本発明は、表面に凹部が形成されている被処理体の表面に薄膜を形成する成膜方法において、前記凹部の内面を含む前記被処理体の表面に第１の窒化チタン膜を形成する工程であって、前記凹部の内面を含む前記被処理体の表面にチタン化合物ガスと還元ガスとを用いてチタン膜を形成するチタン膜形成工程と、窒化ガスを用いて前記チタン膜形成工程により形成された前記チタン膜を全て窒化して窒化チタン膜を形成する窒化工程と、をこの順番でそれぞれ少なくとも１回実行することにより第１の窒化チタン膜を形成する工程と、前記第１の窒化チタン膜の上に第２の窒化チタン膜を堆積させることにより形成する窒化チタン膜堆積工程により第２の窒化チタン膜を形成する工程と、を有する薄膜の成膜方法を提供する。 That is, the present invention provides a film forming method for forming a thin film on a surface of an object to be processed having a recess formed on the surface, wherein the first titanium nitride film is formed on the surface of the object to be processed including the inner surface of the recess. A titanium film forming step of forming a titanium film on the surface of the object including the inner surface of the recess using a titanium compound gas and a reducing gas, and a titanium film forming step using a nitriding gas Performing a nitriding step of nitriding all of the titanium film formed by the step of forming a titanium nitride film in this order at least once, and forming the first titanium nitride film, And a step of forming a second titanium nitride film by a titanium nitride film deposition step formed by depositing a second titanium nitride film on the titanium nitride film.
　前記第１の窒化チタン膜を形成する工程は、前記チタン膜形成工程と前記窒化工程とを交互に複数回繰り返すことにより実行することができる。また、前記チタン膜形成工程と前記窒化工程は、それぞれプラズマの存在下で行うことができる。 The step of forming the first titanium nitride film can be executed by alternately repeating the titanium film forming step and the nitriding step a plurality of times. The titanium film forming step and the nitriding step can be performed in the presence of plasma, respectively.
　前記凹部の底部には、シリコンを含む導電層が露出していてもよく、この場合、前記チタン膜形成工程では前記導電層のシリコンと前記チタン膜のチタンとが反応してチタンシリサイド層が形成されるように前記被処理体を第１の温度に設定することができる。この第１の温度は、４００～６５０℃の範囲内とすることができる。 A conductive layer containing silicon may be exposed at the bottom of the recess. In this case, in the titanium film forming step, silicon in the conductive layer reacts with titanium in the titanium film to form a titanium silicide layer. As described above, the object to be processed can be set to the first temperature. This first temperature may be in the range of 400-650 ° C.
　前記第１の窒化チタン膜を形成する工程において形成される前記第１の窒化チタン膜の膜厚は１５ｎｍ以下とすることができる。 The film thickness of the first titanium nitride film formed in the step of forming the first titanium nitride film can be 15 nm or less.
　前記窒化チタン膜堆積工程では、チタン化合物ガスと還元ガスと窒素ガスとプラズマ安定用ガスとを用いてプラズマの存在下で前記第２の窒化チタン膜を堆積させるようにしてもよい。 In the titanium nitride film deposition step, the second titanium nitride film may be deposited in the presence of plasma using a titanium compound gas, a reducing gas, a nitrogen gas, and a plasma stabilizing gas.
　前記窒素ガスの流量Ｙ１と、前記プラズマを生成するために投入する高周波電力Ｘ１との関係が、前記チタン化合物ガスの流量に依存して定まる所定の関係式を満たすように前記流量Ｙ１と前記高周波電力Ｘ１とを設定することができる。
　前記所定の関係式は、前記チタン化合物ガスの流量が２０ｓｃｃｍ以下の時には、下記の数式１とすることができる。
　Ｙ１≦７．６２・１０－４・Ｘ１ ２－２．３７・Ｘ１＋２．０２・１０３
　　　　　　　　　　　　　　　　　　　　　　　　　　　…（数式１）
　この場合、前記窒素ガスの流量Ｙ１の下限は１ｓｃｃｍであることが好ましい。 The flow rate Y 1 of the nitrogen gas, the relationship between the high-frequency power X 1 to be introduced in order to generate the plasma, said to satisfy a predetermined relational expression determined depending on the flow rate of the titanium compound gas flow rate Y 1 it can be set and the high frequency power X 1 and.
The predetermined relational expression can be expressed by the following mathematical formula 1 when the flow rate of the titanium compound gas is 20 sccm or less.
Y 1 ≦ 7.62 · 10 −4 · X 1 2 −2.37 · X 1 + 2.02 · 10 3
... (Formula 1)
In this case, the lower limit of the flow rate Y 1 of the nitrogen gas is preferably 1 sccm.
　また、前記窒素ガスの前記被処理体の単位面積当りの流量Ｙ２と、前記プラズマを形成するために投入する前記被処理体の単位面積当りの高周波電力Ｘ２との関係が、前記チタン化合物ガスの前記被処理体の単位面積当りの流量に依存して定まる所定の関係式を満たすように前記流量Ｙ２と前記高周波電力Ｘ２とを設定することができる。
　前記所定の関係式は、前記チタン化合物ガスの前記被処理体の単位面積当りの流量が２．８３１・１０－２ｓｃｃｍ／ｃｍ２以下の時には、下記の数式２とすることができる。
　Ｙ２≦５．３９・１０－１・Ｘ２ ２－２．３７・Ｘ２＋２．８６…（数式２）
　この場合、前記窒素ガスの前記被処理体の単位面積当りの流量Ｙ２の下限は、１．４１５・１０－３ｓｃｃｍ／ｃｍ２とすることが好ましい。 Further, the flow rate Y 2 per unit area of the object to be processed of the nitrogen gas, the relationship between the high-frequency power X 2 per unit area of the object to be processed to be introduced to form the plasma, the titanium compound The flow rate Y 2 and the high-frequency power X 2 can be set so as to satisfy a predetermined relational expression determined depending on the flow rate of gas per unit area of the object to be processed.
The predetermined relational expression can be expressed by the following mathematical expression 2 when the flow rate of the titanium compound gas per unit area of the object to be processed is 2.831 · 10 −2 sccm / cm 2 or less.
Y 2 ≦ 5.39 · 10 −1 · X 2 2 −2.37 · X 2 +2.86 (Formula 2)
In this case, the lower limit of the flow rate Y 2 of nitrogen gas per unit area of the object to be processed is preferably 1.415 · 10 −3 sccm / cm 2 .
　また、前記窒素ガスの分圧Ｙ３と、プラズマを生成するために投入する前記被処理体の単位面積当りの高周波電力Ｘ３との関係が、前記チタン化合物ガスの分圧に依存して定まる所定の関係式を満たすように前記分圧Ｙ３と前記高周波電力Ｘ３とを設定することができる。
　前記所定の関係式は、チタン化合物ガスの分圧が２．３７Ｐａ以下の時には、下記の数式３とすることができる。
　Ｙ３≦２８．９・１０１・Ｘ３ ２－１４０・Ｘ３＋１．８７・１０２
　　　　　　　　　　　　　　　　　　　　　　　　　　　…（数式３）
　この場合、前記窒素ガスの分圧Ｙ３の下限は、０．１２Ｐａであることが好ましい。 Further, the relationship between the partial pressure Y 3 of the nitrogen gas and the high-frequency power X 3 per unit area of the object to be processed to generate plasma is determined depending on the partial pressure of the titanium compound gas. it can be set as the partial pressure Y 3 so as to satisfy a predetermined relational expression and the high frequency power X 3.
The predetermined relational expression can be expressed by the following mathematical formula 3 when the partial pressure of the titanium compound gas is 2.37 Pa or less.
Y 3 ≦ 28.9 · 10 1 · X 3 2 −140 · X 3 + 1.87 · 10 2
... (Formula 3)
In this case, partial lower limit of the pressure Y 3 of the nitrogen gas is preferably 0.12 Pa.
　前記チタン膜形成工程と前記窒化工程と前記窒化チタン膜堆積工程とは同一の成膜装置内で行われることを特徴とすることが好ましく、これによれば、必要とする成膜装置の台数を減少させることができ、設備コストの削減に寄与することができる。 Preferably, the titanium film forming step, the nitriding step, and the titanium nitride film depositing step are performed in the same film forming apparatus, and according to this, the number of film forming apparatuses required is reduced. This can be reduced and can contribute to the reduction of the equipment cost.
　前記チタン化合物ガスは、四塩化チタンガスとすることができる。 The titanium compound gas can be titanium tetrachloride gas.
　前記還元ガスは、Ｈ２ガスとすることができる。 The reducing gas can be H 2 gas.
　前記第２の窒化チタン膜の上にタングステン膜を形成して前記凹部を埋め込むタングステン膜形成工程をさらに行うことができる。 It is possible to further perform a tungsten film forming step of forming a tungsten film on the second titanium nitride film and filling the recess.
　さらに本発明は、表面に凹部が形成されている被処理体の表面に薄膜を形成する成膜装置において、前記被処理体を収容する処理容器と、前記処理容器内で前記被処理体を載置すると共に下部電極が設けられた載置台と、前記処理容器内へガスを導入すると共に上部電極として兼用されるシャワーヘッド部と、前記シャワーヘッド部に接続されて必要なガスを供給するガス供給手段と、前記被処理体を加熱する加熱手段と、前記処理容器内を真空排気する排気系と、前記処理容器内でプラズマを形成するために高周波電力を供給する高周波電力供給手段と、上記の薄膜の成膜方法を実施するように装置全体を制御する制御部と、を備えた成膜装置を提供する。 Furthermore, the present invention provides a film forming apparatus for forming a thin film on a surface of an object to be processed in which a recess is formed on the surface, a processing container for accommodating the object to be processed, and the object to be processed in the processing container. And a mounting table provided with a lower electrode, a shower head unit that introduces gas into the processing vessel and also serves as an upper electrode, and a gas supply that supplies the necessary gas connected to the shower head unit Means, heating means for heating the object to be processed, an exhaust system for evacuating the inside of the processing container, high-frequency power supply means for supplying high-frequency power to form plasma in the processing container, There is provided a film forming apparatus including a control unit that controls the entire apparatus so as to perform a thin film forming method.
　さらに本発明は、被処理体を収容する処理容器と、前記処理容器内で前記被処理体を載置すると共に下部電極が設けられた載置台と、前記処理容器内へガスを導入すると共に上部電極として兼用されるシャワーヘッド部と、前記シャワーヘッド部に接続されて必要なガスを供給するガス供給手段と、前記被処理体を加熱する加熱手段と、前記処理容器内を真空排気する排気系と、前記処理容器内でプラズマを形成するために高周波電力を供給する高周波電力供給手段と、装置全体を制御する制御部と、を備えた成膜装置を用いて表面に凹部が形成されている被処理体の表面に薄膜を形成するに際して、上記の薄膜の成膜方法を実施するように装置全体を制御するコンピュータに読み取り可能なプログラムを記憶する記憶媒体を提供する。 Furthermore, the present invention provides a processing container that accommodates an object to be processed, a mounting table on which the object to be processed is mounted in the processing container and provided with a lower electrode, a gas that is introduced into the processing container and an upper part Shower head part also used as an electrode, gas supply means connected to the shower head part for supplying necessary gas, heating means for heating the object to be processed, and exhaust system for evacuating the inside of the processing vessel A concave portion is formed on the surface using a film forming apparatus comprising: a high-frequency power supply means for supplying high-frequency power to form plasma in the processing container; and a control unit for controlling the entire apparatus. When a thin film is formed on the surface of an object to be processed, a storage medium for storing a computer-readable program for controlling the entire apparatus so as to carry out the above-described thin film forming method is provided.
本発明に係る成膜装置の一例を示す断面構成図である。It is a section lineblock diagram showing an example of a film deposition system concerning the present invention. 本発明の成膜方法の一例を示すフローチャートである。It is a flowchart which shows an example of the film-forming method of this invention. 本発明方法により被処理体の表面に形成される薄膜の状態を説明するための説明図である。It is explanatory drawing for demonstrating the state of the thin film formed on the surface of a to-be-processed object by this invention method. 第１の窒化チタン膜の形成時の各ガスの供給状態を示すタイミングチャートである。It is a timing chart which shows the supply state of each gas at the time of formation of the 1st titanium nitride film. 第２の窒化チタン膜を堆積する場合においてＲＦ電力（高周波電力）を一定にした時のＮ２ガス流量とＴｉＣｌ４ガス流量との関係を説明するグラフである。Is a graph illustrating the relationship between the N 2 gas flow rate and the TiCl 4 gas flow rate when the constant RF power (RF power) in the case of depositing a second titanium nitride film. 第２の窒化チタン膜を形成する場合においてＮ２ガス流量とＲＦ電力とＴｉＣｌ４ガス流量とが膜厚のピークの変動に与える影響を説明するためのグラフである。6 is a graph for explaining the influence of the N 2 gas flow rate, the RF power, and the TiCl 4 gas flow rate on the change in film thickness peak when the second titanium nitride film is formed. 第２の窒化チタン膜を堆積する時の高周波電力に対するＮ２ガス流量の最適な範囲を説明するためのグラフである。It is a graph for explaining the optimum range of the N 2 gas flow rate to the high-frequency power at the time of depositing the second titanium nitride film. 第２の窒化チタン膜を堆積する時の被処理体の単位面積当りの高周波電力に対する被処理体の単位面積当りのＮ２ガス流量の最適な範囲を説明するためのグラフである。It is a graph for explaining the optimum range of the N 2 gas flow rate per unit area of the object with respect to the high frequency power per unit area of the object at the time of depositing the second titanium nitride film. 第２の窒化チタン膜を堆積する時の被処理体の単位面積当りの高周波電力に対するＮ２ガスの分圧の最適な範囲を説明するためのグラフである。It is a graph for explaining the optimum range of the partial pressure of N 2 gas to the high frequency power per unit area of the object at the time of depositing the second titanium nitride film. ＲＦ電力が８００Ｗ、ＴｉＣｌ４ガス流量が１２ｓｃｃｍの時のＮ２ガス流量と膜厚との関係を取り出して示したグラフである。RF power is 800 W, is a graph showing the TiCl 4 gas flow takes out the relationship between the N 2 gas flow rate and the film thickness when the 12 sccm. 凹部の底面近傍における薄膜の堆積状態を示す電子顕微鏡写真である。It is an electron micrograph which shows the deposition state of the thin film in the bottom face vicinity of a recessed part. 第２の窒化チタン膜を堆積する時のＮ２ガス流量が多い場合と少ない場合に生ずる反応の形態を模式的に示す図である。It is a diagram schematically showing the form of the reaction which occurs when small and when N 2 gas flow rate is high at the time of depositing the second titanium nitride film. タングステン膜を成膜する時の各ガスの供給のタイミングを示すタイミングチャートである。It is a timing chart which shows the timing of supply of each gas at the time of forming a tungsten film. 半導体ウエハにおける一般的なコンタクト構造を示す図である。It is a figure which shows the general contact structure in a semiconductor wafer.
　以下に、本発明に係る薄膜の成膜方法及び成膜装置の好適な一実施形態を添付図面に基づいて詳述する。ここでは同一の成膜装置内でチタン膜形成工程と窒化工程と窒化チタン膜形成工程を実施する場合について説明する。 Hereinafter, a preferred embodiment of a thin film forming method and film forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings. Here, a case where the titanium film forming process, the nitriding process, and the titanium nitride film forming process are performed in the same film forming apparatus will be described.
　図１に示すように、この成膜装置２２は、略内部が円筒体状になされたアルミニウム、或いはアルミニウム合金製の処理容器２４を有している。この処理容器２４の中には、被処理体としての半導体ウエハＷを水平に支持するための載置台としてのサセプタ２６が、その中央下部に設けられた円筒状の支持部材２８により支持された状態で配置されている。このサセプタ２６は窒化アルミニウム（ＡｌＮ）等のセラミックスからなり、その外縁部にはウエハＷをガイドするためのガイドリング３０が設けられている。 As shown in FIG. 1, the film forming apparatus 22 has a processing container 24 made of aluminum or aluminum alloy, the inside of which is substantially cylindrical. In this processing container 24, a susceptor 26 as a mounting table for horizontally supporting a semiconductor wafer W as an object to be processed is supported by a cylindrical support member 28 provided at the lower center thereof. Is arranged in. The susceptor 26 is made of a ceramic such as aluminum nitride (AlN), and a guide ring 30 for guiding the wafer W is provided on the outer edge thereof.
　また、サセプタ２６にはウエハＷを加熱する加熱手段としてヒータ３２が埋め込まれており、このヒータ３２はヒータ電源３４から給電されることによりウエハＷを所定の温度に加熱する。サセプタ２６には、下部電極３６がヒータ３２の上に埋設されており、この下部電極３６は例えば接地（図示せず）されている。 In addition, a heater 32 is embedded in the susceptor 26 as a heating means for heating the wafer W, and the heater 32 is heated by the heater power supply 34 to heat the wafer W to a predetermined temperature. In the susceptor 26, a lower electrode 36 is embedded on the heater 32, and the lower electrode 36 is grounded (not shown), for example.
　処理容器２４の天壁２４Ａには、絶縁部材３８を介してシャワーヘッド部４０が設けられている。このシャワーヘッド部４０は、大きく分けると上部分であるベース部材４２と下部分であるシャワープレート４４から構成されている。 The shower head section 40 is provided on the top wall 24A of the processing container 24 via an insulating member 38. The shower head portion 40 is roughly composed of a base member 42 as an upper portion and a shower plate 44 as a lower portion.
　ベース部材４２には、ヒータ４６が埋設されており、このヒータ４６はヒータ電源４８から給電されることにより、シャワーヘッド部４０を所定温度に加熱することが可能となっている。 A heater 46 is embedded in the base member 42, and the heater 46 can be heated to a predetermined temperature by being supplied with power from a heater power supply 48.
　シャワープレート４４には処理容器２４内にガスを吐出する多数の吐出孔５０が形成されている。各吐出孔５０は、ベース部材４２とシャワープレート４４の間に形成されるガス拡散空間５２に連通している。ベース部材４２の中央部には処理ガスをガス拡散空間５２に供給するためのガス導入ポート５４が設けられている。ガス導入ポート５４は、後述するガス供給手段５６の混合ガス供給ライン５８に接続されている。 The shower plate 44 is formed with a number of discharge holes 50 for discharging gas into the processing vessel 24. Each discharge hole 50 communicates with a gas diffusion space 52 formed between the base member 42 and the shower plate 44. A gas introduction port 54 for supplying a processing gas to the gas diffusion space 52 is provided at the center of the base member 42. The gas introduction port 54 is connected to a mixed gas supply line 58 of a gas supply means 56 described later.
　ガス供給手段５６は、チタン化合物ガスとして例えば四塩化チタンガスを供給する四塩化チタンガス供給源６０、プラズマ安定用ガスとして例えばアルゴン（以下「Ａｒ」とも称す）ガスを供給するアルゴンガス供給源６２、還元ガスとして例えば水素ガスを供給する水素ガス供給源６４、窒素化合物ガスとして例えばアンモニアガスを供給するアンモニアガス供給源６６及び窒素ガスを供給する窒素ガス供給源６８を有している。 The gas supply means 56 includes, for example, a titanium tetrachloride gas supply source 60 that supplies titanium tetrachloride gas as a titanium compound gas, and an argon gas supply source 62 that supplies, for example, argon (hereinafter also referred to as “Ar”) gas as a plasma stabilizing gas. For example, a hydrogen gas supply source 64 for supplying hydrogen gas as a reducing gas, an ammonia gas supply source 66 for supplying ammonia gas as a nitrogen compound gas, and a nitrogen gas supply source 68 for supplying nitrogen gas are provided.
　そして、四塩化チタンガス供給源６０には四塩化チタンガス供給ライン６０Ｌが接続されており、アルゴンガス供給源６２にはアルゴンガス供給ライン６２Ｌが接続されており、水素ガス供給源６４には水素ガス供給ライン６４Ｌが接続されており、アンモニアガス供給源６６にはアンモニアガス供給ライン６６Ｌが接続されており、窒素ガス供給源６８には窒素ガス供給ライン６８Ｌが接続されている。各ガス供給ライン６０Ｌ～６８Ｌにはそれぞれマスフローコントローラ（ＭＦＣ）６０Ｃ～６８Ｃ及びこのマスフローコントローラ６０Ｃ～６８Ｃを挟んで２つのバルブ６０Ｖ～６８Ｖが設けられている。 The titanium tetrachloride gas supply line 60L is connected to the titanium tetrachloride gas supply source 60, the argon gas supply line 62L is connected to the argon gas supply source 62, and the hydrogen gas supply source 64 is supplied with hydrogen. A gas supply line 64L is connected, an ammonia gas supply line 66L is connected to the ammonia gas supply source 66, and a nitrogen gas supply line 68L is connected to the nitrogen gas supply source 68. The gas supply lines 60L to 68L are respectively provided with mass flow controllers (MFC) 60C to 68C and two valves 60V to 68V across the mass flow controllers 60C to 68C.
　そして、上記各ライン６０Ｌ～６８Ｌの先端はガス混合部７０に接続されている。このガス混合部７０は、上記の処理ガスを混合してシャワーヘッド部４０に供給する機能を有するものであり、そのガス流入側には、上記したように各ガス供給ライン６０Ｌ～６８Ｌを介して各ガス供給源６０～６８が接続されており、そのガス流出側には混合ガス供給ライン５８を介してシャワーヘッド部４０が接続されている。 The ends of the lines 60L to 68L are connected to the gas mixing unit 70. The gas mixing unit 70 has a function of mixing the processing gas and supplying it to the shower head unit 40. The gas inflow side is connected to the gas inflow side via the gas supply lines 60L to 68L as described above. The gas supply sources 60 to 68 are connected to each other, and the shower head unit 40 is connected to the gas outflow side via the mixed gas supply line 58.
　プロセス時には、四塩化チタンガス、アルゴンガス、水素ガス、アンモニアガス及び窒素ガスの中から選択された一種類のガスまたは複数のガスの混合ガスが、シャワーヘッド部４０のガス導入ポート５４とガス拡散空間５２を経由して、複数の吐出孔５０から処理容器２４内に導入される。 At the time of the process, one kind of gas selected from titanium tetrachloride gas, argon gas, hydrogen gas, ammonia gas and nitrogen gas or a mixed gas of a plurality of gases is introduced into the gas introduction port 54 of the shower head 40 and gas diffusion. It is introduced into the processing container 24 from the plurality of ejection holes 50 via the space 52.
　このように本実施形態にかかるシャワーヘッド部４０は、各ガスを予め混合して処理容器２４内に供給する、いわゆるプリミックスタイプで構成されているが、各ガスを独立して処理容器２４内に供給する、いわゆるポストミックスタイプで構成するようにしてもよい。 As described above, the shower head unit 40 according to the present embodiment is configured as a so-called premix type in which each gas is mixed in advance and supplied into the processing container 24. However, each gas is independently supplied into the processing container 24. You may make it comprise with what is called a postmix type supplied to.
　シャワーヘッド部４０には、プラズマ発生用の高周波電力を供給する高周波電力供給手段７２が接続されている。この高周波電力供給手段７２は、シャワーヘッド部４０に接続された給電ライン７４を有し、この給電ライン７４には整合器７６及び高周波電源７８が順次介設されており、成膜等の際にこの高周波電源７８からシャワーヘッド部４０に、例えば４５０ｋＨｚの高周波電力を供給することにより、上部電極として兼用されるシャワーヘッド部４０と下部電極３６との間に高周波電界が生じ、処理容器２４内に供給されたガスをプラズマ化し得るようになっている。 The shower head unit 40 is connected to high frequency power supply means 72 for supplying high frequency power for generating plasma. The high-frequency power supply means 72 has a power supply line 74 connected to the shower head unit 40, and a matching unit 76 and a high-frequency power supply 78 are sequentially interposed in the power supply line 74. By supplying high frequency power of, for example, 450 kHz from the high frequency power supply 78 to the shower head unit 40, a high frequency electric field is generated between the shower head unit 40 also serving as the upper electrode and the lower electrode 36, and is generated in the processing container 24. The supplied gas can be converted into plasma.
　また、処理容器２４の底壁２４Ｂの中央部には円形の穴が形成されており、底壁２４Ｂにはこの穴を覆うように下方に向けて突出する排気室８０が設けられている。排気室８０の側面には排気管８２が接続されており、この排気管８２には排気系８４が接続されている。そしてこの排気系８４を作動させることにより処理容器２４内を所定の真空度まで減圧することができる。この排気系８４は図示しない圧力調整弁や真空ポンプを有しており、上述のように真空排気を行う。 In addition, a circular hole is formed in the center of the bottom wall 24B of the processing container 24, and an exhaust chamber 80 that protrudes downward is provided on the bottom wall 24B so as to cover the hole. An exhaust pipe 82 is connected to the side surface of the exhaust chamber 80, and an exhaust system 84 is connected to the exhaust pipe 82. By operating the exhaust system 84, the inside of the processing container 24 can be depressurized to a predetermined degree of vacuum. The exhaust system 84 has a pressure control valve and a vacuum pump (not shown), and performs vacuum exhaust as described above.
　またサセプタ２６には、ウエハＷを支持して昇降させるための３本（２本のみ図示）のウエハ支持ピン８４がサセプタ２６の表面に対して出没可能に設けられ、これらウエハ支持ピン８４は支持板８６に固定されている。そして、ウエハ支持ピン８４は、エアシリンダ等の駆動機構８８により支持板８６を介して昇降される。 The susceptor 26 is provided with three wafer support pins 84 (only two are shown) for supporting the wafer W to be moved up and down so that the wafer support pins 84 can be raised and lowered with respect to the surface of the susceptor 26. It is fixed to the plate 86. The wafer support pins 84 are moved up and down via a support plate 86 by a drive mechanism 88 such as an air cylinder.
　また処理容器２４の側壁２４Ｃには、共通搬送室（図示せず）との間でウエハＷの搬入出を行うための搬入出口９０と、この搬入出口９０を開閉するゲートバルブ９２が設けられている。 The side wall 24C of the processing container 24 is provided with a loading / unloading port 90 for loading / unloading the wafer W to / from a common transfer chamber (not shown) and a gate valve 92 for opening / closing the loading / unloading port 90. Yes.
　このような構成を有する成膜装置２２の全体の動作の制御、例えば各種ガスの供給開始と停止の制御、各ガスの流量制御、ウエハＷの温度制御、処理容器２４内の圧力制御等は、例えばコンピュータよりなる制御部９４によって行われる。この制御に必要なコンピュータに読み取り可能なプログラムは記憶媒体９６に記載されている。この記憶媒体９６は、フレキシブルディスク、ＣＤ（Ｃｏｍｐａｃｔ Ｄｉｓｃ）、ＣＤ－ＲＯＭ、ハードディスク、フラッシュメモリ或いはＤＶＤ等よりなる。 Control of the overall operation of the film forming apparatus 22 having such a configuration, for example, control of starting and stopping the supply of various gases, flow control of each gas, temperature control of the wafer W, pressure control in the processing container 24, etc. For example, this is performed by the control unit 94 formed of a computer. A computer-readable program necessary for this control is described in the storage medium 96. The storage medium 96 includes a flexible disk, CD (Compact Disc), CD-ROM, hard disk, flash memory, DVD, or the like.
　次に、以上のように構成された成膜装置２２を用いて行われる本発明の成膜方法について説明する。まず、未処理の半導体ウエハＷは、図示しない例えばクラスタツール化された処理システムの共通搬送室より、搬送アームを用いて開放されたゲートバルブ９２及び搬入出口９０を介して、処理容器２４内へ搬入される。このウエハＷは、サセプタ２６に設けたウエハ支持ピン８４を上昇させることにより、このウエハ支持ピン８４側に受け渡され、上記搬送アームを後退させた後に上記ウエハ支持ピン８４を降下させることによって上記ウエハＷはサセプタ２６上に載置されることになる。 Next, the film forming method of the present invention performed using the film forming apparatus 22 configured as described above will be described. First, an unprocessed semiconductor wafer W is transferred into a processing container 24 from a common transfer chamber (not shown) of, for example, a cluster tool processing system via a gate valve 92 and a loading / unloading port 90 opened using a transfer arm. It is brought in. The wafer W is transferred to the wafer support pin 84 side by raising the wafer support pin 84 provided on the susceptor 26, and the wafer support pin 84 is lowered after the transfer arm is moved backward. The wafer W is placed on the susceptor 26.
　この処理容器２４内は予め真空引きされており、上記ゲートバルブ９２を閉じることによって処理容器２４内を密閉する。上記半導体ウエハＷの表面には、図１４において説明したように、絶縁層２や凹部６が予め形成されており、その凹部６の底部に下層の配線層やトランジスタのソースやドレイン等の不純物拡散層となる導電層４が露出している。 The inside of the processing container 24 is evacuated in advance, and the processing container 24 is sealed by closing the gate valve 92. As described with reference to FIG. 14, the insulating layer 2 and the recess 6 are formed in advance on the surface of the semiconductor wafer W. Impurity diffusion such as a lower wiring layer and a source and drain of a transistor is formed at the bottom of the recess 6. The conductive layer 4 serving as a layer is exposed.
　そして、サセプタ２６に配置したヒータ３２を駆動してサセプタ２６上のウエハＷを所定の温度に昇温してその温度を維持する。これと同時に、ガス供給手段５６の各ガス源６０～６８より必要な各ガスを流量制御しつつそれぞれ流し、これらの各ガスをガス混合部７０にて混合した後に混合ガス供給ライン５８を介してシャワーヘッド部４０のガス拡散室５２へ導入する。このガス拡散室５２内へ導入された混合ガスは、このガス拡散室５２内を平面方向へ拡散して多数の吐出孔５０より下方の処理空間Ｓに供給されることになる。 Then, the heater 32 disposed on the susceptor 26 is driven to raise the temperature of the wafer W on the susceptor 26 to a predetermined temperature and maintain that temperature. At the same time, necessary gases are flowed from the gas sources 60 to 68 of the gas supply means 56 while controlling the flow rate, and these gases are mixed in the gas mixing unit 70 and then mixed through the mixed gas supply line 58. The gas is introduced into the gas diffusion chamber 52 of the shower head unit 40. The mixed gas introduced into the gas diffusion chamber 52 diffuses in the gas diffusion chamber 52 in the plane direction and is supplied to the processing space S below the numerous discharge holes 50.
　また、このガス供給と同時に、高周波電力供給手段７２を駆動してシャワーヘッド部４０よりなる上部電極とサセプタ２６に設けた下部電極３６との間に高周波電力を印加し、これにより処理空間ＳにＡｒガスを主体とするプラズマを発生させ、以下に説明する各種の処理を実行することになる。 Simultaneously with this gas supply, the high-frequency power supply means 72 is driven to apply high-frequency power between the upper electrode formed of the shower head unit 40 and the lower electrode 36 provided on the susceptor 26, thereby allowing the processing space S to be applied. A plasma mainly composed of Ar gas is generated, and various processes described below are executed.
　まず、上記成膜装置２２を用いて行われる本発明の成膜方法は、凹部の内面を含む被処理体である半導体ウエハの表面に第１の窒化チタン膜を形成する工程であって、凹部の内面を含む前記被処理体の表面にチタン化合物ガスと還元ガスとを用いてチタン膜を形成するチタン膜形成工程と、窒化ガスを用いて前記チタン膜形成工程により形成されたチタン膜を全て窒化して窒化チタン膜を形成する窒化工程と、をこの順番でそれぞれ少なくとも１回ずつ実行することにより第１の窒化チタン膜を形成する工程と、第１の窒化チタン膜の上に第２の窒化チタン膜を堆積させることにより形成する窒化チタン膜堆積工程により第２の窒化チタン膜を形成する工程と、を含んでいる。ここで「堆積させることにより形成」とは、明確に区別できる独立した２工程（窒化されていない膜の成膜（堆積）工程およびその後の窒化工程）により第１の窒化チタン膜を形成するのとは対照的に、実質的に１工程により（第２の）窒化チタン膜を堆積させることを意味しており、典型的には、チタン化合物ガスと窒化性ガスとを同時に供給することにより直接的に窒化チタン膜を堆積させることを意味している。 First, the film forming method of the present invention performed using the film forming apparatus 22 is a step of forming a first titanium nitride film on the surface of a semiconductor wafer that is an object to be processed including the inner surface of the concave portion. All of the titanium film formed by the titanium film forming step using the titanium compound gas and the reducing gas on the surface of the object including the inner surface of the substrate and the titanium film forming step using the nitriding gas. Performing a nitridation step of forming a titanium nitride film by nitriding at least once in this order, and forming a first titanium nitride film on the first titanium nitride film. And a step of forming a second titanium nitride film by a titanium nitride film deposition step formed by depositing a titanium nitride film. Here, “formation by deposition” means that the first titanium nitride film is formed by two independent processes (film formation (deposition) process of non-nitrided film and subsequent nitridation process) that can be clearly distinguished from each other. In contrast, it means that the (second) titanium nitride film is deposited substantially in one step, typically directly by supplying a titanium compound gas and a nitriding gas simultaneously. This means that a titanium nitride film is deposited.
　これを図２及び図３も参照して説明すると、まず、半導体ウエハＷの表面には図３（Ａ）に示すように、ＳｉＯ２等よりなる層間絶縁層等の絶縁層２に凹部６が前工程で予め形成されており、この凹部６の底部にＳｉを含む導電層４が露出している。そして、ステップＳ１に示すように、このウエハＷの表面にチタン化合物ガスと還元ガスとを用いてチタン膜１００を形成するチタン膜形成工程を行う。上記チタン化合物ガスとしては例えばＴｉＣｌ４ガスを用い、還元ガスとしては例えばＨ２ガスを用いる。 To explain this with reference also to FIG. 2 and FIG. 3, first, as the surface of the semiconductor wafer W shown in FIG. 3 (A), the recess 6 in the insulating layer 2 of the interlayer insulating layer and the like made of SiO 2 or the like is It is formed in advance in the previous step, and the conductive layer 4 containing Si is exposed at the bottom of the recess 6. Then, as shown in step S <b> 1, a titanium film forming process is performed in which a titanium film 100 is formed on the surface of the wafer W using a titanium compound gas and a reducing gas. For example, TiCl 4 gas is used as the titanium compound gas, and H 2 gas is used as the reducing gas.
　このチタン膜形成工程は、後述するように例えばＳＦＤ（Ｓｅｑｕｅｎｔｉａｌ Ｆｌｏｗ Ｄｅｐｏｓｉｔｉｏｎ）法により行われる。また、この際、チタン膜１００と導電層４との境界部分ではチタンがシリサイド化してチタンシリサイド層１０２が形成される。 This titanium film forming step is performed by, for example, an SFD (Sequential Flow Deposition) method as described later. At this time, titanium is silicided at the boundary between the titanium film 100 and the conductive layer 4 to form a titanium silicide layer 102.
　次に、ステップＳ２に示すように、窒化ガスを用いて上記チタン膜１００を全て窒化して第１の窒化チタン膜１０４を形成する窒化工程を行う。上記窒化ガスとしては例えばＮＨ３ガスを用いる。 Next, as shown in step S <b> 2, a nitriding process is performed in which the titanium film 100 is entirely nitrided using a nitriding gas to form a first titanium nitride film 104. For example, NH 3 gas is used as the nitriding gas.
　そして、ステップＳ３に示すように、上記ステップＳ１のチタン膜成膜工程とステップＳ２の窒化工程とを交互に所定の回数だけ繰り返す。この場合、繰り返し回数は「１」、或いは複数回でもよいが、繰り返し回数がゼロで、両ステップＳ１、Ｓ２を共に１回のみ行って（ワンパス）、次のステップＳ４へ移行するようにしてもよい。 Then, as shown in step S3, the titanium film forming process in step S1 and the nitriding process in step S2 are alternately repeated a predetermined number of times. In this case, the number of repetitions may be “1” or a plurality of times, but the number of repetitions is zero, both steps S1 and S2 are performed only once (one pass), and the process proceeds to the next step S4. Good.
　次に、ステップＳ４に示すように、凹部６の内面を含むウエハＷの表面に第２の窒化チタン膜１０６を堆積させる。ここでは、後述するように、チタン化合物ガスと還元ガスと窒化ガスとプラズマ安定用ガスとを用いてプラズマの存在下で上記第２の窒化チタン膜１０６が形成される。これにより、上記第１と第２の窒化チタン膜１０４、１０６で構成されるバリヤ層１０８が形成されることになる。 Next, as shown in step S 4, a second titanium nitride film 106 is deposited on the surface of the wafer W including the inner surface of the recess 6. Here, as will be described later, the second titanium nitride film 106 is formed in the presence of plasma using a titanium compound gas, a reducing gas, a nitriding gas, and a plasma stabilizing gas. As a result, a barrier layer 108 composed of the first and second titanium nitride films 104 and 106 is formed.
　このように、バリヤ層１０８を形成したならば、次にステップＳ５に示すように、ウエハＷの表面にタングステン膜１１０を形成して上記凹部６を埋め込むタングステン膜形成工程を行うことになる。 When the barrier layer 108 is formed in this way, a tungsten film forming step for forming the tungsten film 110 on the surface of the wafer W and burying the recess 6 is performed as shown in step S5.
　次に、上記各工程について詳しく説明する。
＜チタン膜形成工程と窒化工程＞
　まず、チタン膜形成工程と窒化工程について説明する。ここでは図４に示すように、チタン膜形成工程と窒化工程とを交互に複数回繰り返し行う。すなわち、第１の窒化チタン膜１０４を形成するためには、薄いチタン膜１００を形成してこれを窒化する工程を何度か繰り返して第１の窒化チタン膜１０４を形成するプラズマＳＦＤ（Ｓｅｑｕｅｎｔｉａｌ Ｆｌｏｗ Ｄｅｐｏｓｉｔｉｏｎ）法を用いることができる。 Next, the above steps will be described in detail.
<Titanium film forming process and nitriding process>
First, a titanium film forming process and a nitriding process will be described. Here, as shown in FIG. 4, the titanium film forming step and the nitriding step are alternately repeated a plurality of times. In other words, in order to form the first titanium nitride film 104, a plasma SFD (Sequential Flow) for forming the first titanium nitride film 104 by repeatedly forming the thin titanium film 100 and nitriding the thin titanium film 100 several times. Deposition) method can be used.
　このプラズマＳＦＤ法による第１の窒化チタン膜１０４の形成処理では、例えばチタン化合物ガスとアルゴンガスと水素ガスを同時期に供給しつつプラズマを生成して、薄いチタン膜１００を形成するチタン膜形成工程と、アンモニアガスとアルゴンガスと水素ガスを同時期に供給しつつプラズマを生成して、その薄いチタン膜１００の全てを窒化する窒化工程とを１サイクルとして、これを第１の窒化チタン膜１０４が所定の膜厚に達するまで複数回繰り返す。 In the formation process of the first titanium nitride film 104 by the plasma SFD method, for example, a titanium film is formed by generating plasma while supplying titanium compound gas, argon gas, and hydrogen gas at the same time to form a thin titanium film 100. The process and the nitriding step of generating plasma while supplying ammonia gas, argon gas and hydrogen gas at the same time and nitriding all of the thin titanium film 100 are defined as one cycle, and this is the first titanium nitride film. Repeat several times until 104 reaches a predetermined film thickness.
　具体的には、プロセス温度（ウエハ温度）を４００～６５０℃の範囲内（請求項における第１の温度）、より好ましくは４００～５６０℃の範囲内、例えば５５０℃に設定し、プロセス圧力を例えば５００～８００Ｐａの範囲内、例えば６６７Ｐａに設定する。そして、期間Ｐ１１（ガス安定化）にて、四塩化チタンガス（チタン化合物ガス）と水素ガス（還元ガス）とアルゴンガスを供給する。このとき、四塩化チタンガスの流量を例えば１２ｓｃｃｍに調整し、水素ガスの流量を例えば４０００ｓｃｃｍに調整し、アルゴンガスの流量を例えば１６００ｓｃｃｍに調整する。なお、この期間Ｐ１１の主な目的は、次の期間Ｐ１２に先立って処理容器２４内の処理ガスを安定化させることにある。期間Ｐ１１の時間は例えば０～５秒とする。 Specifically, the process temperature (wafer temperature) is set within the range of 400 to 650 ° C. (first temperature in the claims), more preferably within the range of 400 to 560 ° C., for example, 550 ° C., and the process pressure is set to For example, it is set within a range of 500 to 800 Pa, for example, 667 Pa. Then, during a period P11 (gas stabilization), titanium tetrachloride gas (titanium compound gas), hydrogen gas (reducing gas), and argon gas are supplied. At this time, the flow rate of titanium tetrachloride gas is adjusted to, for example, 12 sccm, the flow rate of hydrogen gas is adjusted to, for example, 4000 sccm, and the flow rate of argon gas is adjusted to, for example, 1600 sccm. The main purpose of this period P11 is to stabilize the processing gas in the processing container 24 prior to the next period P12. The period P11 is set to 0 to 5 seconds, for example.
　次に、期間Ｐ１２にて、四塩化チタンガス、水素ガス、およびアルゴンガスを、期間Ｐ１１から同じ流量で継続して供給したまま、シャワーヘッド部（上部電極）４０に例えば８００Ｗの高周波電力を印加してプラズマを形成する。これによって、チタン膜１００が堆積する。このチタン膜１００のチタンは、下層の導電層４との境界部分でシリコンと反応してシリサイド化する。期間Ｐ１２の時間は例えば４秒とする。 Next, in period P12, a high frequency power of, for example, 800 W is applied to the shower head portion (upper electrode) 40 while titanium tetrachloride gas, hydrogen gas, and argon gas are continuously supplied from the period P11 at the same flow rate. And plasma is formed. Thereby, the titanium film 100 is deposited. Titanium in the titanium film 100 reacts with silicon at the boundary with the lower conductive layer 4 to be silicided. The period P12 is set to 4 seconds, for example.
　続いて、期間Ｐ１２の状態から四塩化チタンガスの供給を停止して期間Ｐ１３へ移行する。この期間Ｐ１３では、水素ガスとアルゴンガスを期間Ｐ１２と同じ流量で供給し、これらをプラズマ化する。これによって、先の期間Ｐ１２にて堆積したチタン膜１００がプラズマアニールされる。期間Ｐ１３の時間は例えば５秒とする。 Subsequently, the supply of titanium tetrachloride gas is stopped from the state of period P12, and the process proceeds to period P13. In this period P13, hydrogen gas and argon gas are supplied at the same flow rate as in period P12, and these are turned into plasma. As a result, the titanium film 100 deposited in the previous period P12 is plasma annealed. The period P13 is set to 5 seconds, for example.
　次いで、期間Ｐ１３の状態からプラズマを消して期間Ｐ１４に移行する。この期間Ｐ１４は、次の期間Ｐ１５が開始されるまでの待ち時間であり、この時間は例えば１秒とする。以上の期間Ｐ１１～Ｐ１４の処理を実行することで、極めて薄いチタン膜１００が形成される。なお，期間Ｐ１１～Ｐ１４では、アルゴンガスを導入しないようにしてもよい。 Next, the plasma is extinguished from the state of the period P13 and the process proceeds to the period P14. This period P14 is a waiting time until the next period P15 is started, and this time is, for example, 1 second. By executing the processes in the above periods P11 to P14, an extremely thin titanium film 100 is formed. Note that argon gas may not be introduced during the periods P11 to P14.
　次に、期間Ｐ１５にて、期間Ｐ１１～Ｐ１４の処理によって形成されたチタン膜１００を全て窒化し、極めて薄い第１の窒化チタン膜１０４を形成する。ここでは、水素ガス、アルゴンガス、およびアンモニアガス（窒素化合物ガス）を供給するとともに、シャワーヘッド部（上部電極）４０に例えば８００Ｗの高周波電力を印加してプラズマを再び形成する。このとき水素ガスの流量を例えば２０００ｓｃｃｍに調整し、アルゴンガスの流量を例えば１６００ｓｃｃｍに調整し、アンモニアガスの流量を例えば１５００ｓｃｃｍに調整する。期間Ｐ１５の時間は例えば５秒とする。 Next, in the period P15, all of the titanium film 100 formed by the treatment in the periods P11 to P14 is nitrided to form the very thin first titanium nitride film 104. Here, hydrogen gas, argon gas, and ammonia gas (nitrogen compound gas) are supplied, and a high frequency power of, for example, 800 W is applied to the shower head (upper electrode) 40 to form plasma again. At this time, the flow rate of hydrogen gas is adjusted to 2000 sccm, the flow rate of argon gas is adjusted to 1600 sccm, for example, and the flow rate of ammonia gas is adjusted to 1500 sccm, for example. The period P15 is set to 5 seconds, for example.
　次の期間Ｐ１６ではプラズマを消すとともに、アンモニアガスの供給を止める。水素ガスとアルゴンガスについては、期間Ｐ１５のときと同じ流量に調整し、これらのガスによって処理容器２４内に残留しているアンモニアガスをパージする。これによって、次のサイクルの期間Ｐ１１において、処理容器２４内に供給される四塩化チタンガスが残留アンモニアガスと混合してしまうことが防止され、より良質な第１の窒化チタン膜を形成することができる。この期間Ｐ１６の時間は例えば２秒とする。 In the next period P16, the plasma is turned off and the supply of ammonia gas is stopped. The hydrogen gas and the argon gas are adjusted to the same flow rate as in the period P15, and the ammonia gas remaining in the processing container 24 is purged with these gases. This prevents the titanium tetrachloride gas supplied into the processing container 24 from being mixed with the residual ammonia gas in the period P11 of the next cycle, and forms a higher quality first titanium nitride film. Can do. The period P16 is set to 2 seconds, for example.
　以上の期間Ｐ１１～Ｐ１６の各処理を１サイクルとして、第１の窒化チタン膜１０４が所定の膜厚１～１５ｎｍの範囲内、例えば１０ｎｍに達するまで同サイクルを繰り返す。このようにして、図３（Ｃ）に示すように、所定の厚さの第１の窒化チタン１０４が形成される。尚、ここでは成膜のためにプラズマＳＦＤ法を用いたが、これに替えて、特開２００４－２３２０８０号公報（若しくはこれに対応する米国公開公報ＵＳ２００５２３３０９３Ａ１（その内容は参照により本明細書に組み込まれたものとする））に示されているようなプラズマＣＶＤ法を用いて、すなわち図４におけるＰ１２（チタン膜成膜）とＰ１３（プラズマアニール）からなるサイクルを１回あるいは複数回繰り返し、例えば１０ｎｍの膜厚のチタン膜を形成し、この後に図４におけるＰ１５（窒化処理）によりこのチタン膜の全てをプラズマによって窒化する方法を採用してもよい。 Each process in the above periods P11 to P16 is set as one cycle, and the same cycle is repeated until the first titanium nitride film 104 reaches a predetermined film thickness of 1 to 15 nm, for example, 10 nm. In this way, as shown in FIG. 3C, the first titanium nitride 104 having a predetermined thickness is formed. In this case, the plasma SFD method is used for film formation, but instead of this, Japanese Patent Application Laid-Open No. 2004-232080 (or US publication US2005233093A1 corresponding thereto) is incorporated herein by reference. 4), that is, a cycle consisting of P12 (titanium film formation) and P13 (plasma annealing) in FIG. 4 is repeated once or a plurality of times, for example, A method may be adopted in which a titanium film having a thickness of 10 nm is formed, and thereafter, the entire titanium film is nitrided by plasma by P15 (nitriding treatment) in FIG.
　＜窒化チタン膜堆積工程＞
　次に、図３（Ｄ）に示すように第２の窒化チタン膜１０６を形成する。この第２の窒化チタン膜１０６を形成する理由は、上記第１の窒化チタン膜１０４の膜厚だけでは、後工程で用いる六フッ化タングステンに起因するフッ素ガス成分に対するバリヤ性が不十分であり、また、プラズマＳＦＤ法でバリヤ性が十分な膜厚まで第１の窒化チタン膜を形成するにはこのプラズマＳＦＤ法の成膜レートが非常に小さいので、スループットが大幅に低下してしまう、といった理由からである。 <Titanium nitride film deposition process>
Next, as shown in FIG. 3D, a second titanium nitride film 106 is formed. The reason why the second titanium nitride film 106 is formed is that the film thickness of the first titanium nitride film 104 alone is not sufficient in barrier properties against fluorine gas components caused by tungsten hexafluoride used in a subsequent process. In addition, in order to form the first titanium nitride film with a sufficient barrier property by the plasma SFD method, the deposition rate of the plasma SFD method is very low, and thus the throughput is greatly reduced. For reasons.
　この第２の窒化チタン膜堆積工程で重要な点は、後工程で凹部６に対するタングステンの埋め込み量を十分に確保するために、いかに凹部６の側面に対する成膜を抑制しつつ凹部６の底面への成膜を行うか、という点である。換言すれば、図３（Ｄ）において、凹部６内の第２の窒化チタン膜１０６に関して、凹部６内の側壁の厚さＴ１はできるだけ薄くし、且つ底面の厚さＴ２はできるだけ厚くすることが必要となる。特に、更なる微細化傾向により、凹部６の穴径が６０ｎｍ以下になると、凹部６内の表面への成膜のコントロールが重要となる。 The important point in the second titanium nitride film deposition step is to suppress the film formation on the side surface of the recess 6 and to the bottom surface of the recess 6 in order to secure a sufficient amount of tungsten embedded in the recess 6 in a later step. Whether to perform the film formation. In other words, in FIG. 3D, regarding the second titanium nitride film 106 in the recess 6, the thickness T1 of the side wall in the recess 6 is made as thin as possible, and the thickness T2 of the bottom is made as thick as possible. Necessary. In particular, when the hole diameter of the recess 6 becomes 60 nm or less due to a further miniaturization tendency, control of film formation on the surface in the recess 6 becomes important.
　本発明では、この窒化チタン膜堆積工程におけるＮ２ガスの流量を最適化させることにより、上記目的を達成しようとするものである。具体的には、ここではチタン化合物ガスと還元ガスと窒素ガスとプラズマ安定用ガスとを用いており、チタン化合物ガスとしては例えばＴｉＣｌ４ガスを用い、還元ガスとしては例えばＨ２ガスを用い、プラズマ安定用ガスとしては例えばＡｒガスを用いている。そして、上記４種類のガスを同時に処理容器２４内へ供給すると共に、高周波電力をシャワーヘッド部４０に印加してプラズマを発生させ、これによって各ガスの活性種を発生させてウエハＷの凹部６内の表面を含むウエハ表面全体に第２の窒化チタン膜をプラズマＣＶＤ処理によって形成する。 In the present invention, the above object is achieved by optimizing the flow rate of N 2 gas in the titanium nitride film deposition step. Specifically, here, a titanium compound gas, a reducing gas, a nitrogen gas, and a plasma stabilizing gas are used. For example, a TiCl 4 gas is used as the titanium compound gas, and an H 2 gas is used as the reducing gas. For example, Ar gas is used as the plasma stabilizing gas. Then, the above four types of gases are simultaneously supplied into the processing vessel 24, and high frequency power is applied to the shower head unit 40 to generate plasma, thereby generating active species of each gas and generating recesses 6 in the wafer W. A second titanium nitride film is formed on the entire wafer surface including the inner surface by plasma CVD.
　この場合、各ガスの流量、特にＮ２ガスの流量を最適化するように制御し、且つプラズマ形成用の投入する高周波電力等も制御することにより、凹部６の側壁への成膜を抑制しつつ凹部６の底部への成膜を促進させる。尚、この場合、ウエハＷの絶縁層２の上面にも窒化チタン膜が堆積するのは勿論である。 In this case, film formation on the sidewall of the recess 6 is suppressed by controlling the flow rate of each gas, particularly the flow rate of N 2 gas, and also controlling the high-frequency power input for plasma formation. The film formation on the bottom of the recess 6 is promoted. In this case, of course, a titanium nitride film is deposited also on the upper surface of the insulating layer 2 of the wafer W.
　本発明者等は、凹部６内の表面に対する窒化チタンの成膜状態は、主に四塩化チタンとＮ２の各ガス流量及び投入する高周波電力に大きく依存することを見い出し、これらを最適化するようにしている。言い換えれば、第２の窒化チタン膜を堆積させるにあたって、プラズマ処理、とりわけプラズマＣＶＤ処理を用い、四塩化チタンとＮ２の各ガス流量及び投入する高周波電力を適切にコントロールすることにより、凹部６内の側面への堆積を抑制しつつ底面への堆積を促進させることができるのである。 The present inventors have found that the film formation state of titanium nitride on the surface in the recess 6 largely depends on the gas flow rates of titanium tetrachloride and N 2 and the high-frequency power to be supplied, and optimize these. I am doing so. In other words, when depositing the second titanium nitride film, plasma treatment, particularly plasma CVD treatment is used, and the gas flow rates of titanium tetrachloride and N 2 and the high-frequency power to be input are appropriately controlled, so that the inside of the recess 6 The deposition on the bottom surface can be promoted while the deposition on the side surface of the substrate is suppressed.
　まず、図５を参照して第２の窒化チタン膜を堆積する場合において、高周波電力（ＲＦ電力）を一定にした時のＮ２ガス流量とＴｉＣｌ４ガス流量との関係を説明する。図５において、横軸にはＮ２ガス流量をとり、縦軸には膜厚をとっている。そして、ＴｉＣｌ４ガスは８ｓｃｃｍ～２０ｓｃｃｍまで変化させている。この時のＲＦ電力は８００Ｗ（ワット）で一定である。また、ここではウエハ直径が３００ｍｍに対応する処理容器を用いており、この容積は７０６．５ｃｍ３であり、この点はこれ以降に説明する各グラフにおいても同じである。 First, the relationship between the N 2 gas flow rate and the TiCl 4 gas flow rate when the high frequency power (RF power) is made constant when the second titanium nitride film is deposited will be described with reference to FIG. In FIG. 5, the horizontal axis represents the N 2 gas flow rate, and the vertical axis represents the film thickness. The TiCl 4 gas is changed from 8 sccm to 20 sccm. The RF power at this time is constant at 800 W (watts). Further, here, a processing vessel corresponding to a wafer diameter of 300 mm is used, and its volume is 706.5 cm 3 , and this point is the same in each graph described hereinafter.
　図５のグラフから明らかなように、ＴｉＣｌ４ガス流量を固定してＮ２ガス流量を変化させると、あるＮ２ガス流量において膜厚ピーク値をとる。ピークの位置はＴｉＣｌ４ガス流量に依存して左右方向へ移動している。例えばＴｉＣｌ４ガス流量が８ｓｃｃｍの時のピークＫ１はＮ２ガス流量が１００ｓｃｃｍ程度の時、ＴｉＣｌ４ガス流量が１２ｓｃｃｍの時のピークＫ２はＮ２ガス流量が２００ｓｃｃｍ程度の時、ＴｉＣｌ４ガス流量が１６ｓｃｃｍの時のピークＫ３はＮ２ガス流量が３８０ｓｃｃｍ程度の時、ＴｉＣｌ４ガス流量が２０ｓｃｃｍの時のピークＫ４はＮ２ガス流量が４００ｓｃｃｍ程度の時にそれぞれ現れる。 As is clear from the graph of FIG. 5, when the N 2 gas flow rate is changed while the TiCl 4 gas flow rate is fixed, the film thickness peak value is obtained at a certain N 2 gas flow rate. The peak position moves in the left-right direction depending on the TiCl 4 gas flow rate. For example, when the TiCl 4 gas flow rate is 8 sccm, the peak K1 is when the N 2 gas flow rate is about 100 sccm, and when the TiCl 4 gas flow rate is 12 sccm, the peak K2 is when the N 2 gas flow rate is about 200 sccm, and the TiCl 4 gas flow rate is when peak K3 when the 16sccm the N 2 gas flow rate of about 380Sccm, peak K4 when the TiCl 4 gas flow 20sccm the N 2 gas flow rate respectively appear when about 400 sccm.
　ここで、ウエハの凹部６内の表面の膜厚状態を電子顕微鏡写真で確認したところ、各ＴｉＣｌ４ガス流量におけるピークＫ１～Ｋ４よりもそれぞれの左側の領域の堆積状態が、それぞれの右側の領域と比較して非常に良好であった。すなわち、各ピークＫ１～Ｋ４よりもそれぞれの左側の領域では、凹部６内の側面への堆積を抑制しつつ底面への堆積を促進させることができることが判った。 Here, when the film thickness state of the surface in the recess 6 of the wafer was confirmed by an electron micrograph, the deposition state in the region on the left side of each of the peaks K1 to K4 at each TiCl 4 gas flow rate is the region on the right side. It was very good compared with. That is, it has been found that in the region on the left side of each of the peaks K1 to K4, the deposition on the bottom surface can be promoted while the deposition on the side surface in the recess 6 is suppressed.
　次に、図６を参照して第２の窒化チタン膜を堆積する場合において、Ｎ２ガス流量とＲＦ電力とＴｉＣｌ４ガス流量とが膜厚のピークの変動に与える影響について説明する。図６において、横軸はＮ２ガス流量をとり、縦軸に膜厚をとっており、ＲＦ電力は４００Ｗ～１２００Ｗまで変化させている。また、ＴｉＣｌ４ガスの流量に関して、図６（Ａ）は２０ｓｃｃｍの場合を示し、図６（Ｂ）は１２ｓｃｃｍの場合を示し、図６（Ｃ）は６ｓｃｃｍの場合を示している。 Next, the influence of the N 2 gas flow rate, the RF power, and the TiCl 4 gas flow rate on the fluctuation of the film thickness peak when the second titanium nitride film is deposited will be described with reference to FIG. In FIG. 6, the horizontal axis represents the N 2 gas flow rate, the vertical axis represents the film thickness, and the RF power is varied from 400 W to 1200 W. Further, with respect to the flow rate of TiCl 4 gas FIG. 6 (A) is shown a case of 20 sccm, FIG 6 (B) shows a case of 12 sccm, FIG. 6 (C) shows a case of 6 sccm.
　ここで図６（Ａ）におけるＲＦ電力４００Ｗ、８００Ｗ、１２００Ｗの各曲線のピークをそれぞれＭ１、Ｍ２、Ｍ３とし、図６（Ｂ）におけるＲＦ電力４００Ｗ、８００Ｗ、１２００Ｗの各曲線のピークをそれぞれＮ１、Ｎ２、Ｎ３とし、図６（Ｃ）におけるＲＦ電力４００Ｗ、８００Ｗ、１２００Ｗの各曲線のピークをそれぞれＯ１、Ｏ２、Ｏ３とする。 Here, the peaks of the curves of the RF powers 400 W, 800 W, and 1200 W in FIG. 6A are M1, M2, and M3, respectively, and the peaks of the curves of the RF powers 400 W, 800 W, and 1200 W in FIG. , N2, and N3, and the peaks of the curves of RF power 400W, 800W, and 1200W in FIG. 6C are O1, O2, and O3, respectively.
　この図６から明らかなように、ＴｉＣｌ４ガスの流量が一定の場合には、膜厚のピークは、ＲＦ電力が小さい程、右側へシフトしている。従って、ＴｉＣｌ４ガスの流量が一定の場合には、ＲＦ電力が小さい程、膜厚のピークはＮ２ガス流量が多い方向へシフトしており、ＲＦ電力が大きい程、膜厚のピークはＮ２ ガス流量が少ない方向へシフトしている。この点は、図６（Ａ）～図６（Ｃ）の各グラフにおいて共通である。そして、ＴｉＣｌ４ガスの流量が少なくなる程、各グラフのピークは左側へシフトしていることが判る（図６（Ｃ）参照）。 As is apparent from FIG. 6, when the flow rate of TiCl 4 gas is constant, the peak of the film thickness shifts to the right side as the RF power decreases. Therefore, when the flow rate of TiCl 4 gas is constant, the peak of the film thickness shifts in a direction where the N 2 gas flow rate increases as the RF power decreases, and the peak of the film thickness increases as the RF power increases. The gas flow is shifting in the direction of less. This point is common to the graphs of FIGS. 6A to 6C. It can be seen that the peak of each graph shifts to the left side as the flow rate of TiCl 4 gas decreases (see FIG. 6C).
　ここでウエハの凹部６内の表面の膜厚状態を電子顕微鏡で確認したところ、図６（Ａ）～図６（Ｃ）の各グラフの各ＴｉＣｌ４ガス流量において、ピークＭ１～Ｍ３、Ｎ１～Ｎ３、Ｏ１～Ｏ３よりも左側の領域における堆積状態が、右側の領域と比較して非常に良好であった。この点は、図５の場合と同様である。そして、上記図６における各ピークを連ねることによって形成される曲線のグラフを求めたので、その結果を図７に示す。この図７により第２の窒化チタン膜を堆積する時の高周波電力に対するＮ２ガス流量の最適な範囲を説明することができる。 Here, when the film thickness state of the surface in the concave portion 6 of the wafer was confirmed with an electron microscope, peaks M1 to M3 and N1 to N1 at each TiCl 4 gas flow rate in each graph of FIGS. 6 (A) to 6 (C). The deposition state in the region on the left side of N3 and O1 to O3 was very good as compared with the region on the right side. This is the same as in the case of FIG. And since the graph of the curve formed by connecting each peak in the said FIG. 6 was calculated | required, the result is shown in FIG. FIG. 7 can explain the optimum range of the N 2 gas flow rate with respect to the high-frequency power when depositing the second titanium nitride film.
　図７において、横軸には高周波電力（ＲＦ電力）：Ｘ１をとっており、縦軸にはＮ２ガス流量：Ｙ１をとっている。図７に示すように、図６中の各ピークＭ１～Ｍ３、Ｎ１～Ｎ３、Ｏ１～Ｏ３がＴｉＣｌ４ガスの流量毎にプロットされており、ＴｉＣｌ４ガスの流量が異なる３本の曲線で表されている。そして、図６中の各ピークよりも左側の堆積状態の良好な領域が図７中で表される各曲線の下方の領域となる。すなわち、窒素ガスの流量Ｙ１と、プラズマを生成するために投入する高周波電力Ｘ１との関係が、チタン化合物ガスの流量に依存して定まる所定の関係式を満たすように上記流量Ｙ１と上記高周波電力Ｘ１とが設定されている。 In FIG. 7, the horizontal axis represents high frequency power (RF power): X 1 , and the vertical axis represents N 2 gas flow rate: Y 1 . As shown in FIG. 7, each peak M1 ~ M3 in FIG. 6, N1 ~ N3, O1 ~ O3 is plotted for each flow rate of the TiCl 4 gas, tables in three curves the flow rate different from the TiCl 4 gas Has been. And the area | region with the favorable deposition state of the left side from each peak in FIG. 6 becomes an area | region under each curve represented in FIG. That is, the flow rate Y 1 of the nitrogen gas, the relationship between the high-frequency power X 1 to be introduced to generate plasma, and the flow rate Y 1 so as to satisfy a predetermined relational expression determined depending on the flow rate of the titanium compound gas the high frequency power X 1 are set.
　ここで高周波電力の下限は２００Ｗであり、これよりも高周波電力が小さくなると、プラズマを安定的に形成して維持することが困難になってしまう。また、ＴｉＣｌ４ガスの流量の下限は１ｓｃｃｍであり、この流量が１ｓｃｃｍよりも少なくなると、実質的に窒化チタン膜の成膜が困難になってしまう。特に、実質的な成膜レートを考慮した場合、このＴｉＣｌ４ガスの流量は、４ｓｃｃｍ以上に設定するのが好ましい。また、Ｎ２ガスの流量は上記ＴｉＣｌ４ガスよりも遥かに多量に流すが、その下限は堆積されるＴｉＮ膜の組成を考慮するとＴｉＣｌ４ガスと同じ１ｓｃｃｍであり、この場合も実質的な成膜レートを考慮した場合、４ｓｃｃｍ以上に設定するのが好ましい。 Here, the lower limit of the high frequency power is 200 W, and if the high frequency power becomes smaller than this, it becomes difficult to stably form and maintain the plasma. In addition, the lower limit of the flow rate of the TiCl 4 gas is 1 sccm, and if this flow rate is less than 1 sccm, it is substantially difficult to form a titanium nitride film. In particular, when considering a substantial film forming rate, the flow rate of the TiCl 4 gas is preferably set to 4 sccm or more. The flow rate of the N 2 gas is much larger than that of the TiCl 4 gas, but the lower limit is 1 sccm, which is the same as that of the TiCl 4 gas in consideration of the composition of the deposited TiN film. Considering the film rate, it is preferable to set it to 4 sccm or more.
　そして、上記ＴｉＣｌ４ガス流量が２０ｓｃｃｍの時に定まる窒素ガスの流量Ｙ１と、高周波電力Ｘ１との関係式は以下の数式１のようになり、この数式１を満たすように上記流量Ｙ１と高周波電力Ｘ１とが設定される。
Ｙ１≦７．６２・１０－４・Ｘ１ ２－２．３７・Ｘ１＋２．０２・１０３
　　　　　　　　　　　　　　　　　　　　　　　　　　　…（数式１） Then, the TiCl 4 gas flow rate and flow rate Y 1 of nitrogen gas determined at the time of 20 sccm, a relational expression between the high-frequency power X 1 is as shown in Equation 1 below, and the flow rate Y 1 so as to satisfy this formula 1 a high frequency power X 1 is set.
Y1 ≦ 7.62 · 10 −4 · X 1 2 −2.37 · X 1 + 2.02 · 10 3
... (Formula 1)
　実際的には、上記数式１で表される曲線の下方の領域が最適範囲であり、この領域内に納まるように上記高周波電力Ｘ１とＮ２ガス流量Ｙ１とが設定される。そして図７から明らかなように、数１で示される領域内にＴｉＣｌ４ガス流量が１２ｓｃｃｍの時に定まる最適範囲、及びＴｉＣｌ４ガス流量が６ｓｃｃｍの時に定まる最適範囲も含まれることとなり、数式１で示される領域は、ＴｉＣｌ４ガス流量が２０ｓｃｃｍ以下の時に定まる最適範囲を示していることになる。 Actually, the region below the curve represented by the above formula 1 is the optimum range, and the high frequency power X 1 and the N 2 gas flow rate Y 1 are set so as to fall within this region. And as evident from FIG. 7, will be best range TiCl 4 gas flow rate in the area indicated by the number 1 is determined when 12 sccm, and the TiCl 4 gas flow also includes the optimum range determined at the time of 6 sccm, in Equation 1 The region shown indicates the optimum range determined when the TiCl 4 gas flow rate is 20 sccm or less.
　また、上記ＴｉＣｌ４ガス流量が１２ｓｃｃｍの時に定まる窒素ガスの流量Ｙ１と、高周波電力Ｘ１との関係式は以下の数１－２のようになり、この数式１－２を満たすように上記流量Ｙ１と高周波電力Ｘ１とが設定される。
　Ｙ１≦３．１３・１０－４・Ｘ１ ２－１．１３・Ｘ１＋１０３
　　　　　　　　　　　　　　　　　　　　　　　　　…（数式１－２） The relational expression between the flow rate Y 1 of nitrogen gas determined when the TiCl 4 gas flow rate is 12 sccm and the high-frequency power X 1 is expressed by the following formula 1-2, and the above formula 1-2 is satisfied so as to satisfy the formula 1-2. a flow Y 1 and the high-frequency power X 1 is set.
Y1 ≦ 3.13 · 10 −4 · X 1 2 −1.13 · X 1 +10 3
... (Formula 1-2)
　実際的には、上記数式１－２で表される曲線の下方の領域が最適範囲であり、この領域内に納まるように上記高周波電力Ｘ１とＮ２ガス流量Ｙ１とが設定される。 Actually, the region below the curve expressed by the above equation 1-2 is the optimum range, and the high frequency power X 1 and the N 2 gas flow rate Y 1 are set so as to fall within this region.
　また、上記ＴｉＣｌ４ガス流量が６ｓｃｃｍの時に定まる窒素ガスの流量Ｙ１と、高周波電力Ｘ１との関係式は以下の数式１－３のようになり、この数式１－３を満たすように上記流量Ｙ１と高周波電力Ｘ１とが設定される。
　Ｙ１≦３．１３・１０－４・Ｘ１ ２－８．７５・１０－１・Ｘ１＋６・１０２
　　　　　　　　　　　　　　　　　　　　　　　　　…（数式１－３） Further, the relational expression between the flow rate Y 1 of nitrogen gas determined when the TiCl 4 gas flow rate is 6 sccm and the high frequency power X 1 is expressed by the following formula 1-3, and the above formula 1-3 is satisfied so as to satisfy the formula 1-3. a flow Y 1 and the high-frequency power X 1 is set.
Y 1 ≦ 3.13 · 10 −4 · X 1 2 −8.75 · 10 −1 · X 1 + 6 · 10 2
... (Formula 1-3)
　実際的には、上記数式１－３で表される曲線の下方の領域が最適範囲であり、この領域内に納まるように上記高周波電力Ｘ１とＮ２ガス流量Ｙ１とが設定される。 Actually, the region below the curve represented by the above Formula 1-3 is the optimum range, and the high frequency power X 1 and the N 2 gas flow rate Y 1 are set so as to fall within this region.
　ここでは３本の曲線を一例として示したが、実際にはＴｉＣｌ４ガスの例えば流量毎に多数の上述したような曲線が実験的に予め定まっており、プロセス条件の際に上記ＴｉＣｌ４ガス流量が定まったならば、当該ＴｉＣｌ４ガス流量に対応する曲線（関係式）が図７に示すように予め定まっているので、その曲線よりも下方の流域の範囲に適合するように上記高周波電力Ｘ１やＮ２ガス流量Ｙ１をそれぞれ定めることになる。これにより、ＴｉＣｌ４ガスの任意の設定値に対応できることになる。 Is described as an example the three curves here, actually includes a number of curves as described above previously determined experimentally for each example the flow rate of TiCl 4 gas, the TiCl 4 gas flow rate during the process conditions Is determined, a curve (relational expression) corresponding to the TiCl 4 gas flow rate is determined in advance as shown in FIG. 7, so that the high-frequency power X is adjusted so as to fit the range of the basin below the curve. 1 and N 2 gas flow rate Y 1 are respectively determined. As a result, any set value of the TiCl 4 gas can be handled.
　例えばＴｉＣｌ４ガスの流量を２０ｓｃｃｍに設定した場合には、図７中の斜線で示された領域に対応するように上記高周波電力Ｘ１やＮ２ガス流量Ｙ１をそれぞれ定めることになる。このように高周波電力Ｘ１やＮ２ガス流量Ｙ１を定めることにより、第２のチタン窒化膜１０６の堆積状態を良好にすることができる。尚、この時のプロセス温度は例えば４００～６５０℃程度の範囲内であり、より好ましくは４５０～５５０℃程度の範囲内であり、またプロセス圧力は５００～８００Ｐａ程度の範囲内であり、より好ましくは５００～７００Ｐａ程度の範囲内である。 For example, when the flow rate of TiCl 4 gas is set to 20 sccm, the high-frequency power X 1 and the N 2 gas flow rate Y 1 are respectively determined so as to correspond to the shaded area in FIG. Thus, by determining the high frequency power X 1 and the N 2 gas flow rate Y 1 , the deposition state of the second titanium nitride film 106 can be improved. The process temperature at this time is, for example, in the range of about 400 to 650 ° C., more preferably in the range of about 450 to 550 ° C., and the process pressure is in the range of about 500 to 800 Pa, more preferably. Is in the range of about 500 to 700 Pa.
　また、図７に示す場合では、最適な範囲を成膜装置のプロセス条件の全体（全体として流れるＴｉＣｌ４ガスの流量）を基準として定めたが、これに限定されず、被処理体である半導体ウエハＷの単位面積当りの値に換算して定めるようにしてもよい。図８は第２の窒化チタン膜を堆積する時の被処理体の単位面積当りの高周波電力に対する被処理体の単位面積当りのＮ２ガス流量の最適な範囲を説明するための説明図である。 In the case shown in FIG. 7, the optimum range is determined based on the whole process conditions of the film forming apparatus (the flow rate of TiCl 4 gas flowing as a whole), but the present invention is not limited to this, and the semiconductor that is the object to be processed It may be determined in terms of a value per unit area of the wafer W. FIG. 8 is an explanatory diagram for explaining the optimum range of the N 2 gas flow rate per unit area of the object to be processed with respect to the high frequency power per unit area of the object to be processed when the second titanium nitride film is deposited. .
　図８において横軸にはウエハの単位面積当りの高周波電力をとり、縦軸にはウエハ単位面積当りのＮ２ガス流量をとっている。すなわち、ここでは窒素ガスの上記被処理体の単位面積当りの流量Ｙ２と、プラズマを形成するために投入する上記被処理体の単位面積当りの高周波電力Ｘ２との関係が、上記チタン化合物ガスの上記被処理体の単位面積当りの流量に依存して定まる所定の関係式を満たすように上記流量Ｙ２と上記高周波電力Ｘ２とが設定されている。 In FIG. 8, the horizontal axis represents the high-frequency power per unit area of the wafer, and the vertical axis represents the N 2 gas flow rate per unit area of the wafer. That is, here the flow rate Y 2 per unit area of the object to be processed of the nitrogen gas, the relationship between the high-frequency power X 2 per unit area of the object to be processed to be introduced to form the plasma, the titanium compound The flow rate Y 2 and the high-frequency power X 2 are set so as to satisfy a predetermined relational expression determined depending on the flow rate of the gas per unit area of the object to be processed.
　まず、ウエハの単位面積当りのＴｉＣｌ４ガス流量が２．８３１・１０－２ｓｃｃｍ／ｃｍ２ （２０ｓｃｃｍ対応）の時に定まる関係式は以下の数式２のようになる。
Ｙ２≦５．３９・１０－１・Ｘ２ ２－２．３７・Ｘ２＋２．８６ …（数式２） First, a relational expression determined when the TiCl 4 gas flow rate per unit area of the wafer 2.831 · 10 -2 sccm / cm 2 (20sccm corresponding) is represented by the following Equation 2.
Y 2 ≦ 5.39 · 10 −1 · X 2 2 −2.37 · X 2 +2.86 (Formula 2)
そして図８から明らかなように、数式２で示される領域内に、ウエハの単位面積当りのＴｉＣｌ４ガス流量が１．６９９・１０－２ｓｃｃｍ／ｃｍ２ （１２ｓｃｃｍに対応）および０．８４９・１０－２ｓｃｃｍ／ｃｍ２ （６ｓｃｃｍに対応）の時に定まる最適範囲も含まれることとなり、数式２で示される領域は、ウエハの単位面積当りのＴｉＣｌ４ガス流量が２．８３１・１０－２ｓｃｃｍ／ｃｍ２以下の時に定まる最適範囲を示していることになる。 As is clear from FIG. 8, the TiCl 4 gas flow rate per unit area of the wafer is 1.699 · 10 −2 sccm / cm 2 (corresponding to 12 sccm) and 0.849 · The optimum range determined at 10 −2 sccm / cm 2 (corresponding to 6 sccm) is also included, and the region represented by Formula 2 has a TiCl 4 gas flow rate of 2.831 · 10 −2 sccm per unit area of the wafer. This indicates an optimum range determined when it is less than / cm 2 .
　また、ウエハの単位面積当りのＴｉＣｌ４ガス流量が１．６９９・１０－２ｓｃｃｍ／ｃｍ２（１２ｓｃｃｍ対応）の時に定まる関係式は以下の数式２－２のようになる。
　Ｙ２≦２．２１・１０－１・Ｘ２ ２－１．１３・Ｘ２＋１．４２
　　　　　　　　　　　　　　　　　　　　　　　　　…（数式２－２） Further, a relational expression determined when the TiCl 4 gas flow rate per unit area of the wafer is 1.699 · 10 −2 sccm / cm 2 (corresponding to 12 sccm) is represented by the following Expression 2-2.
Y 2 ≦ 2.21 · 10 −1 · X 2 2 −1.13 · X 2 +1.42
(Formula 2-2)
　また、ウエハの単位面積当りのＴｉＣｌ４ガス流量が０．８４９・１０－２ｓｃｃｍ／ｃｍ２ （６ｓｃｃｍに対応）の時に定まる関係式は以下の数式２－３のようになる。
　Ｙ２≦２．２１・１０－１・Ｘ２ ２－８．７６・１０－１Ｘ２＋０．８４９
　　　　　　　　　　　　　　　　　　　　　　　　　…（数式２－３） Further, the relational expression determined when the TiCl 4 gas flow rate per unit area of the wafer is 0.849 · 10 −2 sccm / cm 2 (corresponding to 6 sccm) is expressed by the following Expression 2-3.
Y 2 ≦ 2.21 · 10 −1 · X 2 2 −8.76 · 10 −1 X 2 +0.849
... (Formula 2-3)
　この時にウエハの単位面積当りのＮ２ガス流量及びＴｉＣｌ４ガス流量の下限は、それぞれ１．４１５・１０－３ｓｃｃｍ／ｃｍ２ （１ｓｃｃｍに対応）であり、好ましくは５．６６２・１０－３ｓｃｃｍ／ｃｍ２（４ｓｃｃｍに対応）である。 At this time, the lower limits of the N 2 gas flow rate and the TiCl 4 gas flow rate per unit area of the wafer are 1.415 · 10 −3 sccm / cm 2 (corresponding to 1 sccm), preferably 5.662 · 10 −3. sccm / cm 2 (corresponding to 4 sccm).
　また図８では半導体ウエハＷの単位面積当りの値に換算して示しているが、これに限定されず、各ガスを分圧に換算して定めるようにしてもよい。図９は第２の窒化チタン膜を堆積する時の被処理体の単位面積当りの高周波電力に対するＮ２ガスの分圧の最適な範囲を説明するための説明図である。 Further, although FIG. 8 shows a value converted into a value per unit area of the semiconductor wafer W, the present invention is not limited to this, and each gas may be determined by converting into a partial pressure. FIG. 9 is an explanatory diagram for explaining an optimum range of the partial pressure of N 2 gas with respect to the high frequency power per unit area of the object to be processed when the second titanium nitride film is deposited.
　図９において横軸にはウエハ単位面積当りの高周波電力をとり、縦軸にはＮ２ガス分圧をとっている。尚、Ａｒガス流量は１６００ｓｃｃｍ、Ｈ２ガス流量は４０００ｓｃｃｍ、プロセス圧力は６６７Ｐａである。すなわち、ここでは上記窒素ガスの分圧Ｙ３と、プラズマを生成するために投入する上記被処理体の単位面積当りの高周波電力Ｘ３との関係が、上記チタン化合物ガスの分圧に依存して定まる所定の関係式を満たすように上記分圧Ｙ３と上記高周波電力Ｘ３とが設定されている。 In FIG. 9, the horizontal axis represents the high frequency power per unit area of the wafer, and the vertical axis represents the N 2 gas partial pressure. The Ar gas flow rate is 1600 sccm, the H 2 gas flow rate is 4000 sccm, and the process pressure is 667 Pa. That is, here the partial pressure Y 3 of the nitrogen gas, the relationship between the high-frequency power X 3 per unit area of the object to be processed to be introduced in order to generate the plasma, depends on the partial pressure of the titanium compound gas and the partial pressure Y 3 so as to satisfy a predetermined relational expression determined Te and the high frequency power X 3 is set.
　まず、ＴｉＣｌ４の分圧が２．３７Ｐａ（２０ｓｃｃｍに対応）の時に定まる関係式は、以下の数式３のようになる。
　Ｙ３≦２８．９・Ｘ３ ２－１４０・Ｘ３＋１８７…（数式３） First, the relational expression determined when the partial pressure of TiCl 4 is 2.37 Pa (corresponding to 20 sccm) is as shown in the following Expression 3.
Y 3 ≦ 28.9 · X 3 2 −140 · X 3 +187 (Formula 3)
　そして図９から明らかなように、数３で示される領域内にＴｉＣｌ４の分圧が１．４３Ｐａ（１２ｓｃｃｍに対応）および０．７１Ｐａ（６ｓｃｃｍに対応）の時に定まる最適範囲も含まれることとなり、数３で示される領域は、ＴｉＣｌ４の分圧が２．３７Ｐａ以下の時に定まる最適範囲を示していることになる。 As is apparent from FIG. 9, the optimum range determined when the partial pressure of TiCl 4 is 1.43 Pa (corresponding to 12 sccm) and 0.71 Pa (corresponding to 6 sccm) is included in the region represented by Equation 3. The region represented by Equation 3 represents the optimum range determined when the partial pressure of TiCl 4 is 2.37 Pa or less.
　また、ＴｉＣｌ４の分圧が１．４３Ｐａ（１２ｓｃｃｍに対応）の時に定まる関係式は、以下の数式３－２のようになる。
　Ｙ３≦１３．１・Ｘ３ ２－７６．３Ｘ３＋１０３…（数式３－２） Further, the relational expression determined when the partial pressure of TiCl 4 is 1.43 Pa (corresponding to 12 sccm) is expressed by the following mathematical expression 3-2.
Y 3 ≦ 13.1 · X 3 2 -76.3X 3 +103 (Formula 3-2)
　また、ＴｉＣｌ４の分圧が０．７１Ｐａ（６ｓｃｃｍ対応）の時に定まる関係式は、以下の数式３－３のようになる。
　Ｙ３≦１６．４・Ｘ３ ２－６７．１・Ｘ３＋６６．６…（数式３－３） Further, the relational expression determined when the partial pressure of TiCl 4 is 0.71 Pa (corresponding to 6 sccm) is expressed by the following Expression 3-3.
Y 3 ≦ 16.4 · X 3 2 −67.1 · X 3 +66.6 (Formula 3-3)
　この時にＮ２ガス及びＴｉＣｌ４ガスの各分圧の下限はそれぞれ０．１２Ｐａ（１ｓｃｃｍに対応）であり、好ましくは０．４８Ｐａ（４ｓｃｃｍに対応）である。 At this time, the lower limit of each partial pressure of N 2 gas and TiCl 4 gas is 0.12 Pa (corresponding to 1 sccm), preferably 0.48 Pa (corresponding to 4 sccm).
　［第２の窒化チタン膜の堆積状態の評価］
　ここで、本発明方法を用いて第２の窒化チタン膜を実際に成膜した時の凹部の底面近傍における薄膜の堆積状態を検査したので、その評価結果について説明する。図１０はＲＦ電力が８００Ｗ、ＴｉＣｌ４ガス流量が１２ｓｃｃｍの時のＮ２ガス流量と膜厚との関係を取り出して示したグラフであり、ここではＮ２ガス流量を１～１０００ｓｃｃｍまで種々変化させて第２の窒化チタン膜を堆積している。このグラフは図６（Ｂ）中の高周波電力が８００Ｗの時の特性と同じグラフである。従って、そのプロセス条件は、高周波電力が８００Ｗ、ＴｉＣｌ４ガス流量が１２ｓｃｃｍ、プロセス温度が５５０℃、凹部６の直径が６０ｎｍである。 [Evaluation of deposition state of second titanium nitride film]
Here, the deposited state of the thin film in the vicinity of the bottom surface of the recess when the second titanium nitride film was actually formed using the method of the present invention was examined, and the evaluation result will be described. FIG. 10 is a graph showing the relationship between the N 2 gas flow rate and the film thickness when the RF power is 800 W and the TiCl 4 gas flow rate is 12 sccm. Here, the N 2 gas flow rate is varied from 1 to 1000 sccm in various ways. A second titanium nitride film is deposited. This graph is the same graph as the characteristic when the high-frequency power in FIG. Therefore, the process conditions are as follows: high-frequency power is 800 W, TiCl 4 gas flow rate is 12 sccm, process temperature is 550 ° C., and the diameter of the recess 6 is 60 nm.
　図１０に示すように、Ｎ２ガス流量を１ｓｃｃｍから増加すると、膜厚は順次増加して行き、そして、Ｎ２ガス流量が３００ｓｃｃｍ程度のところで膜厚はピークＮ２となる。更にＮ２ガス流量を増加して行くと、今度は膜厚は次第に減少して行く。ここで上記ピークＮ２を含まないでこのピークＮ２から右側の領域に対応する処理モードをモード１と称し、ピークＮ２を含んでこのピークＮ２から左側の領域に対応する処理モードをモード２と称す。上記モード２の領域は先に説明していたように第２の窒化チタン膜の堆積状態が良好になる領域である。 As shown in FIG. 10, when the N 2 gas flow rate is increased from 1 sccm, the film thickness sequentially increases, and when the N 2 gas flow rate is about 300 sccm, the film thickness reaches the peak N2. As the N 2 gas flow rate is further increased, the film thickness gradually decreases. Here, the processing mode corresponding to the region on the right side from the peak N2 without including the peak N2 is referred to as mode 1, and the processing mode including the peak N2 and corresponding to the region on the left side from the peak N2 is referred to as mode 2. The region of mode 2 is a region where the second titanium nitride film is deposited well as described above.
　そして、モード１の領域を代表してポイントＡ１（Ｎ２流量 ＝１０００ｓｃｃｍ）の部分と、モード２の領域を代表してポイントＡ２（Ｎ２流量 ＝１００ｓｃｃｍ）の部分の堆積状態をそれぞれ調べたので、その結果を図１１に示す。 Then, the deposition state of the point A1 (N 2 flow rate = 1000 sccm) portion representing the mode 1 region and the point A2 (N 2 flow rate = 100 sccm) portion representing the mode 2 region was examined. The results are shown in FIG.
　図１１は凹部の底面近傍における薄膜の堆積状態を示す電子顕微鏡写真である。ここで図１１（Ａ）はモード１（ポイントＡ１）を示し、図１１（Ｂ）はモード２（ポイントＡ２）を示す。図１１において凹部の断面を示す写真の下部に、凹部の底面付近の拡大写真を併せて示している。堆積時間に関しては、モード１の場合は７０ｓｅｃであり、モード２の場合は２８ｓｅｃである。この結果、モード１の場合はモード２の場合よりも堆積時間が長いにもかかわらず、凹部の底面に堆積している窒化チタン膜（第２の窒化チタン膜）の厚さは略ゼロであるので、ボトムカバレジ（絶縁層の上面に堆積する窒化チタン膜厚に対する凹部底面に堆積する窒化チタン膜厚）は０％であり、好ましくない結果が得られた。 FIG. 11 is an electron micrograph showing the deposition state of the thin film near the bottom of the recess. Here, FIG. 11A shows mode 1 (point A1), and FIG. 11B shows mode 2 (point A2). In FIG. 11, an enlarged photograph of the vicinity of the bottom surface of the concave portion is shown together with the lower portion of the photograph showing the cross section of the concave portion. The deposition time is 70 sec in mode 1 and 28 sec in mode 2. As a result, in the case of mode 1, the thickness of the titanium nitride film (second titanium nitride film) deposited on the bottom surface of the recess is substantially zero although the deposition time is longer than that in mode 2. Therefore, the bottom coverage (the thickness of the titanium nitride deposited on the bottom surface of the recess with respect to the thickness of the titanium nitride deposited on the upper surface of the insulating layer) was 0%, and an undesirable result was obtained.
　これに対して、モード２の場合は、堆積時間が短いにもかかわらず、凹部底面に十分に窒化チタン膜（第２の窒化チタン膜）が堆積してボトムカバレジも３０％程度に達し、好ましい結果を得ることができた。また、このモード２の場合には凹部内の側壁には非常に薄く僅かに窒化チタン膜が堆積している程度であり、この点からもモード２における堆積状態は良好であることを確認することができた。 On the other hand, in the case of mode 2, although the deposition time is short, a titanium nitride film (second titanium nitride film) is sufficiently deposited on the bottom surface of the recess and the bottom coverage reaches about 30%, which is preferable. The result was obtained. In this mode 2, it is confirmed that the titanium nitride film is very thin and slightly deposited on the side wall in the recess. From this point, it is confirmed that the deposition state in mode 2 is good. I was able to.
　次に、上記モード１と堆積状態が良好になるモード２の時に生ずる反応形態の相異を模式的に説明する。図１２は第２の窒化チタン膜を堆積する時のＮ２ガス流量が多い場合と少ない場合に生ずる反応の形態を模式的に示す図である。ここでＮ２ガス流量が多い場合はモード１を示し、Ｎ２ガス流量が少ない場合はモード２を示している。また図１２中の右側には、凹部内に侵入するガスの状態が模式的に併記されている。 Next, the difference in the reaction form occurring in the mode 1 and the mode 2 in which the deposition state is good will be schematically described. FIG. 12 is a diagram schematically showing the form of the reaction that occurs when the N 2 gas flow rate is high and low when depositing the second titanium nitride film. Here, when the N 2 gas flow rate is high, mode 1 is indicated, and when the N 2 gas flow rate is low, mode 2 is indicated. Further, on the right side in FIG. 12, the state of the gas entering the recess is schematically shown.
　図１２（Ａ）に示すように、モード１の場合は、供給されるＮ２ガスが多いことから、このＮ２ガスと還元ガスとして供給されているＨ２ガスとがプラズマにより活性化されて両者が反応して活性種であるＨ*、Ｎ*、ＮＨ* （＊は活性種 を示す）が多量に発生し、このＨ*、Ｎ*、ＮＨ* がウエハ表面に吸着すること になる。そして、このウエハ表面上に吸着したＨ*、Ｎ*、ＮＨ* にＴｉＣｌ４をプラズマにより分解することにより発生したＴｉＣｌｘ（Ｘ：１～３）が反応してこれを還元し、この結果、ＨＣｌが発生すると共に、ウエハ表面にＴｉＮ膜が堆積することになる。 As shown in FIG. 12A, in the case of mode 1, since a large amount of N 2 gas is supplied, the N 2 gas and H 2 gas supplied as a reducing gas are activated by plasma. Both react to generate a large amount of active species H *, N *, NH * (* indicates the active species), and this H *, N *, NH * is adsorbed on the wafer surface. Then, TiClx (X: 1 to 3) generated by the decomposition of TiCl 4 by plasma reacts with H *, N *, NH * adsorbed on the wafer surface to reduce it, and as a result, HCl And a TiN film is deposited on the wafer surface.
　このような反応形態において、ウエハＷの凹部６内の表面には上述のように活性種であるＮＨ*が付着しているが、上記ＴｉＣｌｘは凹部６の開口付近で多く消費されてしまい、凹部６の底部まで十分に届かない状態が生ずる。この結果、モード１の場合には凹部６内の底面にはＴｉＮ膜が十分に堆積しない状態が生ずる。 In such a reaction mode, NH * which is an active species adheres to the surface in the recess 6 of the wafer W as described above. However, the TiClx is consumed in the vicinity of the opening of the recess 6, and the recess A situation occurs where the bottom of 6 is not fully reached. As a result, in the case of mode 1, a state in which the TiN film is not sufficiently deposited on the bottom surface in the recess 6 occurs.
　これに対して、図１２（Ｂ）に示すように、モード２の場合は、供給されるＮ２ガスが少ないことから、ＴｉＣｌ４をプラズマにより分解することにより発生したＴｉＣｌｘ（Ｘ：１～３）がモード１の場合に比べて多くなり、このＴｉＣｌｘがウエハ表面に吸着することになる。そして、このウエハ表面に吸着したＴｉＣｌｘは、Ｎ２及びＨ２をプラズマにより活性化させることにより発生したＮ* 、Ｈ* 、ＮＨ* と反応してこれを還元し、この結果、ＨＣｌが発生すると共に、ウエハ表面にＴｉＮ膜が堆積することになる。 In contrast, as shown in FIG. 12B, in the case of mode 2, since the supplied N 2 gas is small, TiClx (X: 1 to 3) generated by decomposing TiCl 4 by plasma is used. ) Is larger than that in mode 1, and this TiClx is adsorbed on the wafer surface. The TiClx adsorbed on the wafer surface reacts with N *, H *, NH * generated by activating N 2 and H 2 with plasma to reduce it, and as a result, HCl is generated. At the same time, a TiN film is deposited on the wafer surface.
　このような反応形態において、ウエハＷの凹部６内の表面には上述のようにＴｉＣｌｘが付着しているが、Ｎ* 、Ｈ* 、ＮＨ* はＴｉＣｌｘよりも相対的に多いので、Ｎ*、Ｈ* 、ＮＨ* は凹部６の開口付近で消費されても十分に残存していることになって凹部６の底部まで十分に届き、この凹部６の底面上にＴｉＮ膜を十分に堆積させることができることになる。 In such a reaction mode, TiClx adheres to the surface in the recess 6 of the wafer W as described above, but N *, H *, and NH * are relatively larger than TiClx. Even if H * and NH * 十分 are consumed in the vicinity of the opening of the recess 6, they remain sufficiently and reach the bottom of the recess 6 sufficiently, and a TiN film is sufficiently deposited on the bottom surface of the recess 6. Will be able to.
　＜タングステン膜成膜工程＞
　次に、タングステン膜成膜工程について説明する。上述のように第１の窒化チタン膜１０４と第２の窒化チタン膜１０６とを形成することによりバリヤ層１０８を形成したならば、次に、凹部６を埋め込むためのタングステン膜を形成する。図１３はタングステン膜を成膜する時の各ガスの供給のタイミングを示すタイミングチャートである。 <Tungsten film formation process>
Next, the tungsten film forming process will be described. If the barrier layer 108 is formed by forming the first titanium nitride film 104 and the second titanium nitride film 106 as described above, then a tungsten film for filling the recess 6 is formed. FIG. 13 is a timing chart showing the supply timing of each gas when forming a tungsten film.
　このタングステン膜を形成するには、上記ウエハＷを図示しない別のタングステン用の成膜装置へ移載する。このタングステン膜を成膜するには図１に示す成膜装置と同様で、別途設けた熱ＣＶＤ装置等を用いればよい。ここではタングステン含有ガスと還元ガスであるモノシランガスと交互に繰り返し供給して成膜を行うＳＦＤ法を用いるのが好ましい。 In order to form this tungsten film, the wafer W is transferred to another tungsten film forming apparatus (not shown). The tungsten film is formed in the same manner as the film forming apparatus shown in FIG. 1, and a separately provided thermal CVD apparatus or the like may be used. Here, it is preferable to use the SFD method in which a tungsten-containing gas and a monosilane gas as a reducing gas are alternately supplied repeatedly to form a film.
　ただし、このときのウエハ温度（プロセス温度）については、従来の一般的な熱ＣＶＤ処理におけるプロセス温度４００～４５０℃程度よりも低い２５０～３５０℃程度に調整する。また、プロセス圧力については、１００～１０００Ｐａ程度に調整する。そして、期間Ｐ２１にて、熱ＣＶＤ装置内に六フッ化タングステンガスを供給する。このとき、六フッ化タングステンガスの流量を１０～３０ｓｃｃｍに調整する。また、この期間Ｐ２１では、上記六フッ化タングステンガスとともにアルゴンガスまたは窒素ガスをキャリアガスとして供給する。期間Ｐ２１の時間は例えば０．５～５秒とする。 However, the wafer temperature (process temperature) at this time is adjusted to about 250 to 350 ° C., which is lower than the process temperature of about 400 to 450 ° C. in the conventional general thermal CVD process. The process pressure is adjusted to about 100 to 1000 Pa. Then, in the period P21, tungsten hexafluoride gas is supplied into the thermal CVD apparatus. At this time, the flow rate of tungsten hexafluoride gas is adjusted to 10 to 30 sccm. In this period P21, argon gas or nitrogen gas is supplied as a carrier gas together with the tungsten hexafluoride gas. The period P21 is set to 0.5 to 5 seconds, for example.
　次に、期間Ｐ２１の状態から六フッ化タングステンガスの供給を停止して期間Ｐ２２に移行する。この期間Ｐ２２は、次の期間Ｐ２３が開始されるまでの待ち時間であり、この時間は例えば０．５～３．０秒とする。この期間Ｐ２２では、熱ＣＶＤ装置内に、アルゴンガスまたは窒素ガスをパージガスとして供給し続けることが好ましい。 Next, the supply of tungsten hexafluoride gas is stopped from the state of period P21, and the process proceeds to period P22. This period P22 is a waiting time until the next period P23 is started, and this time is, for example, 0.5 to 3.0 seconds. In this period P22, it is preferable to continue supplying argon gas or nitrogen gas as a purge gas into the thermal CVD apparatus.
　続いて、期間Ｐ２３にて、モノシランガスを供給する。このとき、モノシランガスの流量を５０～１００ｓｃｃｍに調整する。また，この期間Ｐ２３では、上記モノシランガスとともにアルゴンガスまたは窒素ガスをキャリアガスとして供給する。期間Ｐ２３の時間は例えば０．５～５秒とする。なお、還元ガスとしては、このモノシランガスに代えて、ジシラン（Ｓｉ２Ｈ６）ガス、ジボラン（Ｂ２Ｈ６）ガスなどを用いることができる。 Subsequently, in a period P23, monosilane gas is supplied. At this time, the flow rate of the monosilane gas is adjusted to 50 to 100 sccm. In this period P23, argon gas or nitrogen gas is supplied as a carrier gas together with the monosilane gas. The period P23 is set to 0.5 to 5 seconds, for example. As the reducing gas, disilane (Si 2 H 6 ) gas, diborane (B 2 H 6 ) gas, or the like can be used instead of the monosilane gas.
　次いで、期間Ｐ２３の状態からモノシランガスの供給を停止して期間Ｐ２４に移行する。この期間Ｐ２４は、次のサイクルの期間Ｐ２１が開始されるまでの待ち時間であり、この時間は例えば０．５～３．０秒とする。この期間Ｐ２４では、熱ＣＶＤ装置内に、アルゴンガスまたは窒素ガスをパージガスとして供給し続けることが好ましい。 Next, the supply of monosilane gas is stopped from the state of period P23, and the process proceeds to period P24. This period P24 is a waiting time until the period P21 of the next cycle is started, and this time is, for example, 0.5 to 3.0 seconds. In this period P24, it is preferable to continue supplying argon gas or nitrogen gas as a purge gas into the thermal CVD apparatus.
　以上の期間Ｐ２１～Ｐ２４の処理を実行することで、極めて薄いタングステン膜が形成される。そして，期間Ｐ２１～Ｐ２４の処理を１サイクルとして、タングステン膜１１０（図３（Ｅ）参照）が所定の膜厚に達し、凹部６内がタングステンで埋められるまで同サイクルを繰り返す。 An extremely thin tungsten film is formed by executing the processes in the above periods P21 to P24. Then, the processing in the periods P21 to P24 is set as one cycle, and the cycle is repeated until the tungsten film 110 (see FIG. 3E) reaches a predetermined film thickness and the recess 6 is filled with tungsten.
　このように、本実施形態にかかるＳＦＤタングステン膜形成処理によれば、六フッ化タングステンガスとモノシランガスを交互に繰り返し供給して、極めて薄いタングステン膜を積層させるようにしてタングステン膜１１０を形成する。したがって、従来の一般的な熱ＣＶＤ処理時のプロセス温度４００～４５０℃よりも遥かに低い２５０～３５０℃であっても、特性の良好なタングステン膜１１０を形成することができる。 As described above, according to the SFD tungsten film forming process according to the present embodiment, the tungsten film 110 is formed by alternately supplying the tungsten hexafluoride gas and the monosilane gas and laminating extremely thin tungsten films. Therefore, the tungsten film 110 with good characteristics can be formed even at a process temperature of 250 to 350 ° C. which is much lower than the process temperature of 400 to 450 ° C. in the conventional general thermal CVD process.
　ところで、ＳＦＤタングステン膜形成処理によれば、上述のように１サイクルで堆積するタングステンの量は極めて少ないため、例えば２００～３００ｎｍの厚さのタングステン膜を形成しようとすると、かなり長いプロセス時間が必要となり、スループットが低下してしまう。そこで、このスループット低下を防止するために、上記のＳＦＤタングステン膜形成処理の後に、高い成膜レートが得られる第２のタングステン膜形成処理を行うようにしてもよい。 By the way, according to the SFD tungsten film forming process, the amount of tungsten deposited in one cycle is extremely small as described above. Therefore, if a tungsten film having a thickness of 200 to 300 nm is formed, for example, a considerably long process time is required. As a result, the throughput decreases. Therefore, in order to prevent this reduction in throughput, a second tungsten film forming process capable of obtaining a high film forming rate may be performed after the above SFD tungsten film forming process.
　この第２のタングステン膜形成処理では、例えば、プロセス温度を４００～４５０℃程度まで上昇させ、プロセス圧力を２０００～２００００Ｐａ程度に調整する。また、還元ガスとしてのモノシランガスを水素ガスに切り換え、キャリアガスとともにこの水素ガスと六フッ化タングステンガスとを同時にかつ連続的に供給する。このとき、水素ガスの流量を例えば３００～３０００ｓｃｃｍ程度とし、六フッ化タングステンガスの流量を３０～３００ｓｃｃｍ程度に調整する。このようなプロセスレシピを用いることによって、高い成膜レート、例えば１０００～５０００Å／ｍｉｎでタングステン膜１１０を形成することができる。 In the second tungsten film forming process, for example, the process temperature is raised to about 400 to 450 ° C., and the process pressure is adjusted to about 2000 to 20000 Pa. Further, the monosilane gas as the reducing gas is switched to hydrogen gas, and the hydrogen gas and tungsten hexafluoride gas are supplied simultaneously and continuously together with the carrier gas. At this time, the flow rate of the hydrogen gas is set to about 300 to 3000 sccm, for example, and the flow rate of the tungsten hexafluoride gas is adjusted to about 30 to 300 sccm. By using such a process recipe, the tungsten film 110 can be formed at a high film formation rate, for example, 1000 to 5000 Å / min.
　以上のように、本実施形態にかかる成膜処理によれば、チタン膜成膜工程によって、薄いチタン膜１００を形成し、これを窒化工程にて窒化することによって例えば１０ｎｍの厚さの第１の窒化チタン膜１０４を形成する。このとき、窒化前のチタン膜１００が薄いために、チタンからなる層を残すことなくそのすべてを確実に窒化することができる。とりわけＳＦＤ法を用いた場合には、各チタン膜成膜工程において形成されるチタン膜が極薄であるため、より確実にチタン膜を完全に窒化することができる。このように、本実施形態によれば、タングステン膜１１０を形成するために用いられる六フッ化タングステンガスに含まれるフッ素と活発に反応するおそれのあるチタン膜が第１の窒化チタン膜１０４の下に存在しなくなるため、第２の窒化チタン膜１０６とタングステン膜１１０がこれらの下地層から剥離することを防止することができる。 As described above, according to the film forming process according to the present embodiment, the thin titanium film 100 is formed by the titanium film forming process, and is nitrided by the nitriding process, whereby the first film having a thickness of, for example, 10 nm is formed. The titanium nitride film 104 is formed. At this time, since the titanium film 100 before nitriding is thin, all of the titanium film 100 can be securely nitrided without leaving a layer made of titanium. In particular, when the SFD method is used, since the titanium film formed in each titanium film forming process is extremely thin, the titanium film can be completely nitrided more reliably. As described above, according to this embodiment, the titanium film that may actively react with fluorine contained in the tungsten hexafluoride gas used to form the tungsten film 110 is formed under the first titanium nitride film 104. Therefore, the second titanium nitride film 106 and the tungsten film 110 can be prevented from being peeled off from these base layers.
　更に、本実施形態では、窒化チタン膜堆積工程にて上記第１の窒化チタン膜１０４上に第２の窒化チタン膜１０６を形成するようにしたので、バリヤ機能を十分に発揮することができ、この結果、この後工程であるタングステン膜形成工程で用いられる六フッ化タングステンのフッ素による拡散を防止することができる。 Further, in the present embodiment, since the second titanium nitride film 106 is formed on the first titanium nitride film 104 in the titanium nitride film deposition step, the barrier function can be sufficiently exhibited, As a result, it is possible to prevent diffusion of tungsten hexafluoride used in the tungsten film forming process, which is a subsequent process, due to fluorine.
　またこの第２の窒化チタン膜１０６を堆積する際、Ｎ２ガス量とプラズマ発生用の高周波電力とＴｉＣｌ４ガス量との関係を最適化するようにしたので、例えば直径が６０ｎｍ以下の微細な凹部（ホール）内であっても、その凹部内の側壁への成膜を抑制しつつ、底面側には十分に窒化チタン膜を成膜することができ、凹部内が閉塞されることを防止することができる。 Further, when the second titanium nitride film 106 is deposited, the relationship among the N 2 gas amount, the high frequency power for plasma generation, and the TiCl 4 gas amount is optimized. Even inside a recess (hole), a titanium nitride film can be sufficiently formed on the bottom surface side while suppressing film formation on the side wall in the recess, preventing the inside of the recess from being blocked. can do.
　このため、後工程のタングステン膜形成工程で上記凹部内に十分にタングステン膜を堆積させることができ、このコンタクト抵抗（プラグ抵抗）等を小さくすることができる。上記実施形態では、チタン膜成膜工程と窒化工程と窒化チタン膜堆積工程とを同一の成膜装置内で連続的に行うようにしたので、スループットを向上させることができる。 For this reason, a tungsten film can be sufficiently deposited in the concave portion in a subsequent tungsten film forming step, and the contact resistance (plug resistance) and the like can be reduced. In the above embodiment, since the titanium film forming step, the nitriding step, and the titanium nitride film depositing step are continuously performed in the same film forming apparatus, the throughput can be improved.
　尚、上記実施形態では、プラズマ安定用ガスとしてＡｒガスを用いたが、これに限定されず、Ｈｅ等の他の希ガスを用いてもよい。また、上記実施形態では、チタン膜成膜工程と窒化工程と窒化チタン膜堆積工程とを同一の成膜装置内で連続的に行うようにしたが、これに限定されず、窒化チタン膜堆積工程を別途設けた別の成膜装置で行うようにしてもよい。 In the above embodiment, Ar gas is used as the plasma stabilizing gas. However, the present invention is not limited to this, and other rare gases such as He may be used. In the above embodiment, the titanium film forming step, the nitriding step, and the titanium nitride film depositing step are continuously performed in the same film forming apparatus. However, the present invention is not limited to this, and the titanium nitride film depositing step is performed. May be performed by another film forming apparatus provided separately.
　また、ここでは被処理体として半導体ウエハを例にとって説明したが、この半導体ウエハにはシリコン基板やＧａＡｓ、ＳｉＣ、ＧａＮなどの化合物半導体基板も含まれる。更には、本発明の成膜方法の成膜対象は、これらの基板に限定されず、液晶表示装置に用いるガラス基板やセラミック基板等であってもよい。 Although the semiconductor wafer is described as an example of the object to be processed here, the semiconductor wafer includes a silicon substrate and a compound semiconductor substrate such as GaAs, SiC, and GaN. Furthermore, the film formation target of the film formation method of the present invention is not limited to these substrates, and may be a glass substrate or a ceramic substrate used for a liquid crystal display device.

Claims (22)

  1. 　表面に凹部が形成されている被処理体の表面に薄膜を形成する成膜方法において、
    　前記凹部の内面を含む前記被処理体の表面に第１の窒化チタン膜を形成する工程であって、前記凹部の内面を含む前記被処理体の表面にチタン化合物ガスと還元ガスとを用いてチタン膜を形成するチタン膜形成工程と、窒化ガスを用いて前記チタン膜形成工程により形成された前記チタン膜を全て窒化して窒化チタン膜を形成する窒化工程と、をこの順番でそれぞれ少なくとも１回ずつ実行することにより第１の窒化チタン膜を形成する工程と、
    　前記第１の窒化チタン膜の上に第２の窒化チタン膜を堆積させることにより形成する窒化チタン膜堆積工程により第２の窒化チタン膜を形成する工程と、
    を有することを特徴とする薄膜の成膜方法。     In a film forming method for forming a thin film on the surface of an object to be processed in which a recess is formed on the surface,
    Forming a first titanium nitride film on the surface of the object to be processed including the inner surface of the recess, using a titanium compound gas and a reducing gas on the surface of the object to be processed including the inner surface of the recess; A titanium film forming step for forming a titanium film, and a nitriding step for nitriding all of the titanium film formed by the titanium film forming step using a nitriding gas to form a titanium nitride film in this order at least 1 each. Forming a first titanium nitride film by performing each time, and
    Forming a second titanium nitride film by a titanium nitride film deposition step formed by depositing a second titanium nitride film on the first titanium nitride film;
    A method for forming a thin film, comprising:
  2. 　前記第１の窒化チタン膜を形成する工程は、前記チタン膜形成工程と前記窒化工程とを交互に複数回繰り返すことにより実行されることを特徴とする請求項１記載の薄膜の成膜方法。 The method of forming a thin film according to claim 1, wherein the step of forming the first titanium nitride film is executed by alternately repeating the titanium film forming step and the nitriding step a plurality of times.
  3. 　前記チタン膜形成工程と前記窒化工程は、それぞれプラズマの存在下で行われることを特徴とする請求項１記載の薄膜の成膜方法。 The thin film forming method according to claim 1, wherein the titanium film forming step and the nitriding step are each performed in the presence of plasma.
  4. 　前記凹部の底部には、シリコンを含む導電層が露出しており、前記チタン膜形成工程では前記導電層のシリコンと前記チタン膜のチタンとが反応してチタンシリサイド層が形成されるように前記被処理体を第１の温度に設定することを特徴とする請求項１記載の薄膜の成膜方法。 A conductive layer containing silicon is exposed at the bottom of the recess, and the titanium silicide layer is formed in the titanium film forming step so that silicon in the conductive layer reacts with titanium in the titanium film. 2. The thin film forming method according to claim 1, wherein the object to be processed is set to a first temperature.
  5. 　前記第１の温度は４００～６５０℃の範囲内であることを特徴とする請求項４記載の薄膜の成膜方法。 The method of forming a thin film according to claim 4, wherein the first temperature is in the range of 400 to 650 ° C.
  6. 　前記第１の窒化チタン膜を形成する工程にて形成される前記第１の窒化チタン膜の膜厚は１５ｎｍ以下であることを特徴とする請求項１記載の薄膜の成膜方法。 2. The method of forming a thin film according to claim 1, wherein the thickness of the first titanium nitride film formed in the step of forming the first titanium nitride film is 15 nm or less.
  7. 　前記窒化チタン膜堆積工程では、チタン化合物ガスと還元ガスと窒素ガスとプラズマ安定用ガスとを用いてプラズマの存在下で前記第２の窒化チタン膜を堆積させるようにしたことを特徴とする請求項１記載の薄膜の成膜方法。 The titanium nitride film deposition step is characterized in that the second titanium nitride film is deposited in the presence of plasma using a titanium compound gas, a reducing gas, a nitrogen gas, and a plasma stabilizing gas. Item 2. A method for forming a thin film according to Item 1.
  8. 　前記窒化チタン膜堆積工程では、前記窒素ガスの流量Ｙ１と、前記プラズマを生成するために投入する高周波電力Ｘ１との関係が、前記チタン化合物ガスの流量に依存して定まる所定の関係式を満たすように前記流量Ｙ１と前記高周波電力Ｘ１とが設定されていることを特徴とする請求項７記載の薄膜の成膜方法。 Wherein the titanium nitride film deposition process, the flow rate Y 1 of the nitrogen gas, the relationship between the high-frequency power X 1 to be introduced in order to generate the plasma, a predetermined relational expression determined depending on the flow rate of the titanium compound gas The thin film deposition method according to claim 7, wherein the flow rate Y 1 and the high-frequency power X 1 are set so as to satisfy
  9. 　前記所定の関係式は、前記チタン化合物ガスの流量が２０ｓｃｃｍ以下の時には、下記の数式１であることを特徴とする請求項８記載の薄膜の成膜方法。
    　Ｙ１≦７．６２・１０－４・Ｘ１ ２－２．３７・Ｘ１＋２．０２・１０３
    　　　　　　　　　　　　　　　　　　　　　　　　　　　…（数式１）     9. The thin film deposition method according to claim 8, wherein the predetermined relational expression is the following mathematical formula 1 when the flow rate of the titanium compound gas is 20 sccm or less.
    Y 1 ≦ 7.62 · 10 −4 · X 1 2 −2.37 · X 1 + 2.02 · 10 3
    ... (Formula 1)
  10. 　前記窒素ガスの流量Ｙ１の下限は１ｓｃｃｍであることを特徴とする請求項９記載の薄膜の成膜方法。 Thin film forming method according to claim 9, wherein the lower limit of the flow rate Y 1 of said nitrogen gas is 1 sccm.
  11. 　前記窒化チタン膜堆積工程では、前記窒素ガスの前記被処理体の単位面積当りの流量Ｙ２と、前記プラズマを形成するために投入する前記被処理体の単位面積当りの高周波電力Ｘ２との関係が、前記チタン化合物ガスの前記被処理体の単位面積当りの流量に依存して定まる所定の関係式を満たすように前記流量Ｙ２と前記高周波電力Ｘ２とが設定されていることを特徴とする請求項７記載の薄膜の成膜方法。 In the titanium nitride film deposition step, a flow rate Y 2 of the nitrogen gas per unit area of the object to be processed and a high-frequency power X 2 per unit area of the object to be processed to form the plasma characterized in that the relationship is the said flow Y 2 so as to satisfy a predetermined relational expression determined the titanium compound gas, depending on the flow rate per unit area of the specimen and the high frequency power X 2 is set The method for forming a thin film according to claim 7.
  12. 　前記所定の関係式は、前記チタン化合物ガスの前記被処理体の単位面積当りの流量が２．８３１・１０－２ｓｃｃｍ／ｃｍ２以下の時には、下記の数式２であることを特徴とする請求項１１記載の薄膜の成膜方法。
    　Ｙ２ ≦５．３９・１０－１・Ｘ２ ２ －２．３７・Ｘ２ ＋２．８６ 
    　　　　　　　　　　　　　　　　　　　　　　　　　　　…（数式２）     The predetermined relational expression is the following mathematical expression 2 when the flow rate of the titanium compound gas per unit area of the object to be processed is 2.831 · 10 −2 sccm / cm 2 or less. Item 12. A method for forming a thin film according to Item 11.
    Y 2 ≦ 5.39 · 10 −1 · X 2 2 −2.37 · X 2 +2.86
    ... (Formula 2)
  13. 　前記窒素ガスの前記被処理体の単位面積当りの流量Ｙ２の下限は、１．４１５・１０－３ｓｃｃｍ／ｃｍ２ であることを特徴とする請求項１２記載の薄膜の成膜方法。 13. The method of forming a thin film according to claim 12, wherein the lower limit of the flow rate Y2 of the nitrogen gas per unit area of the object is 1.415 · 10 −3 sccm / cm 2 .
  14. 　前記窒化チタン膜堆積工程では、前記窒素ガスの分圧Ｙ３と、プラズマを生成するために投入する前記被処理体の単位面積当りの高周波電力Ｘ３との関係が、前記チタン化合物ガスの分圧に依存して定まる所定の関係式を満たすように前記分圧Ｙ３と前記高周波電力Ｘ３とが設定されていることを特徴とする請求項７記載の薄膜の成膜方法。 In the titanium nitride film depositing step, a partial pressure Y 3 of the nitrogen gas, the relationship between the high-frequency power X 3 per unit area of the object to be processed to be introduced to generate plasma, min of the titanium compound gas the partial pressure Y 3 and the RF power X 3 and film formation method of a thin film according to claim 7, characterized in that it is set so as to satisfy a predetermined relational expression determined depending on pressure.
  15. 　前記所定の関係式は、チタン化合物ガスの分圧が２．３７Ｐａ以下の時には、下記の数式３であることを特徴とする請求項１４記載の薄膜の成膜方法。
    　Ｙ３ ≦２８．９・Ｘ３ ２ －１４０・Ｘ３ ＋１．８７・１０２ …（数式３）     15. The method of forming a thin film according to claim 14, wherein the predetermined relational expression is the following mathematical formula 3 when the partial pressure of the titanium compound gas is 2.37 Pa or less.
    Y 3 ≦ 28.9 · X 3 2 −140 · X 3 + 1.87 · 10 2 (Formula 3)
  16. 　前記窒素ガスの分圧Ｙ３の下限は、０．１２Ｐａであることを特徴とする請求項１５記載の薄膜の成膜方法。 Partial lower limit of the pressure Y 3 of the nitrogen gas, thin film forming method according to claim 15, wherein it is 0.12 Pa.
  17. 　前記チタン膜形成工程と前記窒化工程と前記窒化チタン膜堆積工程とは同一の成膜装置内で行われることを特徴とする請求項１乃至１６のいずれか一項に記載の薄膜の成膜方法。 The thin film forming method according to claim 1, wherein the titanium film forming step, the nitriding step, and the titanium nitride film depositing step are performed in the same film forming apparatus. .
  18. 　前記チタン化合物ガスは、四塩化チタンガスであることを特徴とする請求項１記載の薄膜の成膜方法。 2. The method for forming a thin film according to claim 1, wherein the titanium compound gas is titanium tetrachloride gas.
  19. 　前記還元ガスは、水素ガスであることを特徴とする請求項１記載の薄膜の成膜方法。 2. The method of forming a thin film according to claim 1, wherein the reducing gas is hydrogen gas.
  20. 　前記第２の窒化チタン膜の上に、タングステン膜を形成して前記凹部を埋め込むタングステン膜形成工程をさらに有することを特徴とする請求項１記載の薄膜の成膜方法。 The method of forming a thin film according to claim 1, further comprising a tungsten film forming step of forming a tungsten film on the second titanium nitride film and filling the recess.
  21. 　表面に凹部が形成されている被処理体の表面に薄膜を形成する成膜装置において、前記被処理体を収容する処理容器と、前記処理容器内で前記被処理体を載置すると共に下部電極が設けられた載置台と、前記処理容器内へガスを導入すると共に上部電極として兼用されるシャワーヘッド部と、前記シャワーヘッド部に接続されて必要なガスを供給するガス供給手段と、前記被処理体を加熱する加熱手段と、前記処理容器内を真空排気する排気系と、前記処理容器内でプラズマを形成するために高周波電力を供給する高周波電力供給手段と、請求項１乃至２０のいずれか一項に記載の薄膜の成膜方法を実施するために装置全体を制御する制御部と、を備えたことを特徴とする成膜装置。 In a film forming apparatus for forming a thin film on a surface of an object to be processed, the surface of which is formed with a recess, a processing container that houses the object to be processed, and a lower electrode on which the object to be processed is placed in the processing container , A shower head unit that introduces gas into the processing vessel and also serves as an upper electrode, a gas supply unit that is connected to the shower head unit and supplies necessary gas, and The heating means for heating the processing body, the exhaust system for evacuating the inside of the processing container, the high-frequency power supply means for supplying high-frequency power to form plasma in the processing container, and any one of claims 1 to 20 A film forming apparatus comprising: a control unit that controls the entire apparatus in order to implement the thin film forming method according to claim 1.
  22. 　被処理体を収容する処理容器と、前記処理容器内で前記被処理体を載置すると共に下部電極が設けられた載置台と、前記処理容器内へガスを導入すると共に上部電極として兼用されるシャワーヘッド部と、前記シャワーヘッド部に接続されて必要なガスを供給するガス供給手段と、前記被処理体を加熱する加熱手段と、前記処理容器内を真空排気する排気系と、前記処理容器内でプラズマを形成するために高周波電力を供給する高周波電力供給手段と、装置全体を制御する制御部とを備えた成膜装置を用いて表面に凹部が形成されている被処理体の表面に薄膜を形成するに際して、請求項１乃至２０のいずれか一項に記載の薄膜の成膜方法を実施するように装置全体を制御するコンピュータに読み取り可能なプログラムを記憶することを特徴とする記憶媒体。 A processing container that accommodates an object to be processed, a mounting table on which the object to be processed is mounted in the processing container and provided with a lower electrode, and a gas is introduced into the processing container and is also used as an upper electrode A shower head unit, a gas supply unit connected to the shower head unit for supplying necessary gas, a heating unit for heating the object to be processed, an exhaust system for evacuating the inside of the processing vessel, and the processing vessel A high-frequency power supply means for supplying high-frequency power to form plasma in the inside and a film forming apparatus provided with a control unit for controlling the entire apparatus. When the thin film is formed, a computer-readable program is stored in the computer that controls the entire apparatus so as to carry out the thin film forming method according to any one of claims 1 to 20. And the storage medium.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020013828A (en) * 2018-07-13 2020-01-23 富士電機株式会社 Semiconductor device and manufacturing method

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5537197B2 (en) * 2010-03-12 2014-07-02 ルネサスエレクトロニクス株式会社 Manufacturing method of semiconductor device
US8937022B2 (en) * 2010-11-29 2015-01-20 Hitachi Kokusai Electric Inc. Method of manufacturing semiconductor device, substrate processing method and substrate processing apparatus
JP6800004B2 (en) * 2016-02-01 2020-12-16 東京エレクトロン株式会社 Method of forming a silicon nitride film
JP6733516B2 (en) 2016-11-21 2020-08-05 東京エレクトロン株式会社 Method of manufacturing semiconductor device
CN110265354B (en) * 2018-03-12 2022-07-05 长鑫存储技术有限公司 Preparation method of tungsten plug

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09246212A (en) * 1996-03-07 1997-09-19 Sony Corp Formation of barrier layer and semiconductor device with barrier layer formed thereby
JPH10209079A (en) * 1997-01-23 1998-08-07 Nec Corp Manufacture of semiconductor device
JPH11256335A (en) * 1998-03-06 1999-09-21 Sony Corp Chemical vapor phase growing method of metal nitride film and production of electronic device using that
JP2001210713A (en) * 2000-01-24 2001-08-03 Tokyo Electron Ltd Etching method, filling method, and method of forming wiring layer
JP2008112803A (en) * 2006-10-30 2008-05-15 Tokyo Electron Ltd Film forming method, and substrate processing apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09246212A (en) * 1996-03-07 1997-09-19 Sony Corp Formation of barrier layer and semiconductor device with barrier layer formed thereby
JPH10209079A (en) * 1997-01-23 1998-08-07 Nec Corp Manufacture of semiconductor device
JPH11256335A (en) * 1998-03-06 1999-09-21 Sony Corp Chemical vapor phase growing method of metal nitride film and production of electronic device using that
JP2001210713A (en) * 2000-01-24 2001-08-03 Tokyo Electron Ltd Etching method, filling method, and method of forming wiring layer
JP2008112803A (en) * 2006-10-30 2008-05-15 Tokyo Electron Ltd Film forming method, and substrate processing apparatus

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020013828A (en) * 2018-07-13 2020-01-23 富士電機株式会社 Semiconductor device and manufacturing method
JP7283036B2 (en) 2018-07-13 2023-05-30 富士電機株式会社 Semiconductor device and manufacturing method

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