JP4966899B2 - Thin film forming method and semiconductor device manufacturing method - Google Patents

Description

  The present invention relates to a thin film forming method and a semiconductor device manufacturing method.

  In a semiconductor device, with the progress of miniaturization and multilayering, electromigration (EM) due to an increase in current density becomes serious. A multilayer wiring technique of copper wiring having high EM resistance is indispensable for highly integrating semiconductor devices.

  In the multilayer wiring technology of a semiconductor device, in order to improve the productivity and reliability of metal wiring, a base layer having various functions is generally interposed between the insulating layer and the metal wiring. As the underlayer, for example, a barrier layer that prevents diffusion of metal atoms, an adhesion layer that provides adhesion between the metal wiring and the insulating layer, and a seed layer that promotes film growth of the wiring material are known.

  As the material for the underlayer, tantalum, titanium, tantalum nitride, titanium nitride, or the like is used when aluminum or tungsten is used as the wiring material. In copper wiring multilayer technology, a low dielectric constant film is used as an insulating layer. When these metal materials are applied to the underlying layer, moisture and oxygen contained in the insulating layer diffuse into the underlying layer, making the underlying layer easy. It will oxidize. As a result, the resistance value increases and the adhesion decreases, and the reliability of the semiconductor device is greatly impaired.

Therefore, in the multilayer wiring technology of copper wiring, various proposals related to the material of the underlayer have been conventionally made in order to solve the above problems. In Patent Document 1 and Patent Document 2, a ruthenium (Ru) film or a multilayer film including a Ru film is used as a base layer of a copper wiring. The Ru film can suppress an increase in resistance because the oxide has conductivity, and can be used as a stopper layer of an oxidation source for the copper wiring. Further, by laminating an adhesion layer on this Ru film, the adhesion between the Ru film and the copper wiring can be further improved.
JP 2005-129745 A JP 2006-328526 A

A so-called damascene method or dual-damascene method is used as a method for manufacturing copper wiring. That is, a trench corresponding to the wiring shape is formed in the insulating layer in advance, a base layer is laminated on the inner surface of the trench, and a copper material is buried in the trench covered with the base layer to form a copper wiring. Or trench and via hole (Via-Hole
) Are formed in advance, and a base layer is laminated on the inner surfaces of the trench and the via hole, and a copper material is embedded in the trench and via hole covered by the base layer to simultaneously form a copper wiring and a via plug.

  The lower layer wiring connected to the copper wiring through the base layer is exposed on the inner surface of the trench or via when the base layer is stacked on the trench or the like. The exposed lower wiring is easily oxidized by an oxidation source that is present when the Ru film is formed, and the resistance value between the lower wiring and the copper wiring is greatly increased. In addition, the Ru film can obtain conductivity by its own oxide, but its conductivity is limited and does not correspond to the resistance value of the metal Ru. Patent Document 1 and Patent Document 2 give high step coverage and high adhesion to a copper wiring, but have not been sufficiently studied to reduce resistance via a Ru film.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a thin film forming method and a semiconductor device manufacturing method capable of reducing the resistance of a wiring structure including a ruthenium-containing film. And

  In examining the manufacturing process of the ruthenium-containing film, the present inventor treated the ruthenium-containing film formed of a ruthenium complex represented by a specific general formula in an oxidizing gas atmosphere, and reduced the ruthenium-containing film. It has been found that the resistance value of the ruthenium-containing film is greatly reduced by the treatment exposed to the gas atmosphere.

In order to achieve the above object, the invention described in claim 1 is directed to an object of the general formula (1) (wherein R ¹ represents a linear or branched alkyl group having 1 to 4 carbon atoms. .)) Forming a ruthenium-containing film using the organic ruthenium complex and the first reducing gas, exposing the ruthenium-containing film to an oxidizing gas atmosphere, and further forming the ruthenium-containing film in a first step. And a step of exposing to an atmosphere of a bireducible gas.

According to the first aspect of the present invention, the impurities contained in the ruthenium-containing film can be eliminated by the oxidation treatment applied to the specific ruthenium-containing film, and the ruthenium in the oxidized state can be eliminated by the reduction treatment applied to the ruthenium-containing film. Can be reduced. Therefore, the resistance of the ruthenium-containing film can be reduced.

  Invention of Claim 2 is the thin film formation method of Claim 1, Comprising: The said organic ruthenium complex is bis (2-methoxyxy-6-methyl-3,5-heptanedionate) -1,5 hexadiene ruthenium. The gist is that it is a complex.

According to invention of Claim 2, a ruthenium containing film | membrane can be formed more reliably.
Invention of Claim 3 is the thin film formation method of Claim 1 or 2, Comprising: The process of exposing the ruthenium containing film to the second reduction following the step of exposing the ruthenium containing film to the oxidizing gas atmosphere The gist of the present invention is to perform the step of exposing to a gas atmosphere.

  According to the invention of claim 3, the oxidation treatment of the ruthenium-containing film and the reduction treatment of the ruthenium-containing film can be continuously performed, and the oxidation state of the ruthenium-containing film immediately before performing the reduction treatment. Can be given high reproducibility. As a result, the resistance of the ruthenium-containing film can be reduced more reliably.

  Invention of Claim 4 is a thin film formation method as described in any one of Claims 1-3, Comprising: The process of forming the said ruthenium containing film | membrane, The said ruthenium containing film | membrane is made into the said oxidizing gas. The gist is to repeat the step of exposing to the atmosphere and the step of exposing the ruthenium-containing film to the atmosphere of the second reducing gas.

  According to invention of Claim 4, a low resistance ruthenium containing film | membrane can be laminated | stacked by repeating each process. Therefore, the resistance of the ruthenium-containing film can be reduced regardless of the film thickness.

The invention according to claim 5 is the thin film forming method according to any one of claims 1 to 4, wherein the oxidizing gas atmosphere contains oxygen (O ₂ ). .
According to the fifth aspect of the present invention, the ruthenium-containing film can be exposed to an oxygen atmosphere, and the ruthenium-containing film can be more reliably oxidized.

In a sixth aspect of the present invention, in the thin film forming method according to the fifth aspect, the step of exposing to the oxidizing gas atmosphere includes a partial pressure of oxygen (O ₂ ) of 10 ² Pa to 10 ^6. The gist is that the temperature of the object is set to 20 ° C to 500 ° C.

  According to the invention described in claim 6, by defining the oxygen partial pressure and the atmospheric temperature, it is possible to give higher reproducibility to the oxidation treatment of the ruthenium-containing film and to suppress the excessive oxidation. it can.

The invention according to claim 7 is the thin film forming method according to any one of claims 1 to 4, wherein the oxidizing gas atmosphere contains water (H ₂ O). To do.
According to the seventh aspect of the present invention, the ruthenium-containing film can be exposed to an atmosphere of water vapor, and the ruthenium-containing film can be more reliably oxidized.

The invention according to claim 8 is the thin film forming method according to claim 7, wherein the step of exposing to the atmosphere of the oxidizing gas has a partial pressure of water (H ₂ O) of 10 ² Pa to 10 ² . ^The gist is to set the temperature of the object to 20 to 500 ° C. at ⁶ Pa.

  According to the eighth aspect of the present invention, higher reproducibility can be given to the oxidation treatment of the ruthenium-containing film by regulating the partial pressure of the water vapor and the water vapor temperature, and the excessive oxidation is suppressed. be able to.

The invention according to claim 9 is the thin film forming method according to any one of claims 1 to 4, wherein the oxidizing gas atmosphere is air.
According to the invention described in claim 9, the ruthenium-containing film can be oxidized in an atmosphere of water vapor, and the resistance reduction of the ruthenium-containing film can be performed using a simpler method.

  The invention according to claim 10 is the thin film forming method according to claim 9, wherein the step of exposing to the oxidizing gas atmosphere sets the atmospheric humidity to 20% to 100%, and the object. The gist of this is that the temperature is 20 ° C to 500 ° C.

  According to the invention described in claim 10, it is possible to give higher reproducibility to the oxidation treatment of the ruthenium-containing film by regulating the humidity and temperature of the atmosphere, and to suppress the excessive oxidation. it can.

  In invention of Claim 11, It is a thin film formation method as described in any one of Claims 1-10, Comprising: Said 2nd reducing gas dissociates and discharge | releases a hydrogen radical and a hydrogen ion. Is the gist.

According to the eleventh aspect of the present invention, the reduction treatment can be more reliably performed on the ruthenium-containing film subjected to the oxidation treatment by the reducing power of hydrogen ions.
In the invention described in claim 12, a thin film forming method according to any one of claims 1 to 11, wherein the first reducing gas, hydrogen (H _2), ammonia (NH _3), The gist is that it is at least one selected from the group consisting of a hydrazine derivative, silane (SiH ₄ ), and disilane (Si ₂ H ₆ ).

  According to the invention of claim 12, the ruthenium-containing film subjected to the oxidation treatment can be exposed to a highly reducing gas atmosphere, and the ruthenium-containing film is more reliably subjected to the reduction treatment. Can do.

  In a thirteenth aspect of the present invention, in the thin film forming method according to the twelfth aspect of the present invention, the hydrazine derivative contains one or two hydrogen atoms of hydrazine, a methyl group, an ethyl group, and a straight chain. Or it makes it a summary to be substituted with a group selected from the group consisting of branched butyl groups.

According to the invention described in claim 13, a simpler configuration can be used as the hydrazine derivative, and the versatility of the present invention can be improved.
In invention of Claim 14, It is a thin film formation method as described in any one of Claims 1-13, Comprising: The process exposed to the atmosphere of said 2nd reducing gas is the said 2nd reducing gas. The gist is to set the atmosphere to 10 ⁻¹ Pa to 10 ⁶ Pa.

According to the invention described in claim 14, higher reproducibility can be given to the reduction treatment of the ruthenium-containing film by the regulation of the pressure of the second reducing gas.
In invention of Claim 15, It is a thin film formation method as described in any one of Claims 1-13, Comprising: The process of forming the said ruthenium containing film | membrane forms the temperature of the said target object in 150 degreeC ~. The gist is to set the temperature to 500 ° C.

  According to the invention described in claim 15, higher reproducibility can be given to the reduction treatment of the ruthenium-containing film by defining the temperature of the second reducing gas.

  As described above, according to the present invention, it is possible to provide a method for forming a thin film and a method for manufacturing a semiconductor device that can reduce the resistance of a wiring structure including a ruthenium-containing film.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. First, a thin film forming apparatus used for the thin film forming method of the present invention will be described.
FIG. 1 is a plan view schematically showing the thin film forming apparatus 10. In FIG. 1, a thin film forming apparatus 10 includes a load lock chamber FL (hereinafter simply referred to as an LL chamber FL), a transfer chamber FT connected to the LL chamber FL, a Ru chamber F1 connected to the transfer chamber FT, It has an oxidation chamber F2 and a reduction chamber F3.

  The LL chamber FL has an internal space that can be decompressed (hereinafter simply referred to as a storage chamber FLa), and carries in and out a plurality of substrates S. The LL chamber FL depressurizes the storage chamber FLa when starting the film formation process of the substrate S, and carries the substrate S into the transfer chamber FT. When the film formation process of the substrate S is completed, the LL chamber FL The air is released to the atmosphere, and the substrate S is carried out of the thin film forming apparatus 10. As the substrate S, for example, a silicon substrate or a glass substrate can be used.

The transfer chamber FT has an internal space that can be decompressed (hereinafter simply referred to as a transfer chamber FTa), and is in a releasably communicating manner with the LL chamber FL, the Ru chamber F1, the oxidation chamber F2, and the reduction chamber F3. Can be formed. The transfer chamber FTa is equipped with a transfer robot RB for transferring the substrate S, and loads the substrate S of the LL chamber FL into the transfer chamber FT when starting the film forming process of the substrate S. The transfer robot RB transfers the substrate S to the Ru chamber F1, subsequently to the oxidation chamber F2, and then to the reduction chamber F3 based on the data related to the transfer path.

  Next, the Ru chamber F1, the oxidation chamber F2, and the reduction chamber F3 will be described below. FIG. 2 is a side sectional view schematically showing the configuration of the Ru chamber F1. Since the oxidation chamber F2 and the reduction chamber F3 are obtained by changing the raw material supply unit SU of the Ru chamber F1, only the changed points of the oxidation chamber F2 and the reduction chamber F3 will be described.

  The Ru chamber F1 is a CVD chamber for forming a ruthenium (Ru) film on the substrate S using a CVD method. In FIG. 2, the Ru chamber F1 is connected to the transfer chamber FT and has a bottomed cylindrical chamber main body 21 that opens at the top, and is disposed on the top of the chamber main body 21 so that the upper opening of the chamber main body 21 can be opened and closed. A chamber lid 22 is provided. The chamber body 21 has an opening closed by the chamber lid 22, thereby forming a space surrounded by the chamber body 21 and the chamber lid 22 (hereinafter simply referred to as a processing space Fa).

  The processing space Fa includes a stage 23 on which the substrate S carried from the transfer chamber FT is placed. The stage 23 is equipped with a heater H connected to a heater power source HG. When the heater H is driven, the substrate S to be placed is adjusted to a predetermined temperature (for example, 20 ° C. to 500 ° C.).

An exhaust unit PU is connected to the right side of the processing space Fa via an exhaust port P0, and a pressure sensor PG1 that detects the pressure of the processing space Fa and outputs a detection result is connected to the left side of the processing space Fa. Has been. The exhaust unit PU is composed of various exhaust devices P such as an exhaust valve V1, a pressure adjustment valve V2, a raw material trap T, a turbo molecular pump, and a dry pump, and the pressure adjustment valve V2 is driven according to the detection result of the pressure sensor PG1. When this is done, the pressure in the processing space Fa is adjusted to a predetermined pressure (for example, 10 ² Pa to 10 ⁵ Pa). Further, each part of the exhaust unit PU excluding the raw material trap T is adjusted to a predetermined temperature (20 ° C. to 250 ° C.) to avoid liquefaction of the raw material SC exhausted from the processing space Fa and maintain the exhaust capability.

  A shower head 24 for introducing gas into the processing space Fa is disposed above the processing space Fa. The shower head 24 is adjusted to a predetermined temperature (20 ° C. to 250 ° C.), and avoids liquefaction of the introduced raw material SC to facilitate the derivation of the raw material SC. The shower head 24 includes a plurality of first supply holes K1 and a plurality of second supply holes K2 that are independent from the first supply holes K1. Each first supply hole K1 is commonly connected to a first port P1 provided on the upper right side of the chamber lid 22, and each second supply hole K2 is a second port provided on the upper left side of the chamber lid 22, respectively. Commonly connected to P2.

The first port P1 is connected to the mass flow controller MFC1 of the reducing gas Gr and a carrier gas (for example, helium (He 2), argon (Ar ₂ ), nitrogen (N ₂ ) via the gas line Lr.
) Etc.) is connected to the mass flow controller MFC2. The first port P1 uniformly supplies the carrier gas over substantially the entire surface of the substrate S through the first supply holes K1 when the mass flow controller MFC2 introduces a predetermined amount of carrier gas. At this time, when the mass flow controller MFC1 introduces a predetermined amount of the reducing gas Gr, the first port P1 allows the reducing gas Gr conveyed to the carrier gas to flow over substantially the entire surface of the substrate S through the first supply holes K1. Supply evenly.

As the reducing gas Gr, a gas that deviates and releases hydrogen radicals or hydrogen ions can be used. The reducing gas Gr is at least one selected from the group consisting of hydrogen (H ₂ ), ammonia (NH ₃ ), hydrazine derivatives, silane (SiH ₄ ), and disilane (Si ₂ H ₆ ). Can be used. Further, as the hydrazine derivative, one in which one or two hydrogen atoms of hydrazine are substituted with a group selected from the group consisting of a methyl group, an ethyl group, and a linear or branched butyl group is used. Can do. When the flow rate of the reducing gas Gr is sufficiently large to enable stable supply, the carrier gas, that is, the configuration without the mass flow controller MFC2 may be used.

  The second port P2 is connected to the raw material supply unit SU via the raw material gas line Ls. The raw material supply unit SU is connected to a raw material tank 25 for storing a raw material SC of a ruthenium-containing film (hereinafter simply referred to as a Ru film), a liquid mass flow controller LMFC connected to the raw material tank 25, and a liquid mass flow controller LMFC. It has a vaporizer IU. The raw material supply unit SU and the raw material gas line Ls are adjusted to a predetermined temperature (20 ° C. to 250 ° C.) to avoid liquefaction of the raw material SC and to smoothly feed the raw material SC.

  As the raw material SC, an organic ruthenium complex, that is, an organic ruthenium complex having a β-diketone having an alkoxyalkylmethyl group represented by the general formula (1) and 1,5-hexadiene as a ligand can be used. Moreover, as the raw material SC, a solution in which the above-described organoruthenium complex is dissolved in various solvents (for example, hexane, octane, toluene, cyclohexane, methylcyclohexane, ethylcyclohexane, tetrahydrofuran, etc.) can be used.

The raw material tank 25 receives pressure of a derived gas (for example, an inert gas such as He, Ar, N ₂ ) and derives the stored raw material SC at a predetermined pressure. The liquid mass flow controller LMFC adjusts the raw material SC derived from the raw material tank 25 to a predetermined supply amount and introduces the raw material SC into the vaporizer IU. The vaporizer IU vaporizes the raw material SC from the liquid mass flow controller LMFC, and is connected to the mass flow controller MFC3 of a carrier gas (for example, an inert gas such as He, Ar, N ₂ ) to supply the raw material SC together with the carrier gas. Derived to the two-port P2. The second port P2 uniformly supplies the raw material SC from the vaporizer IU over substantially the entire surface of the substrate S through the second supply holes K2.

  Thereby, the Ru chamber F1 can supply each of the reducing gas Gr and the raw material SC to the processing space Fa through independent paths, and the reducing gas Gr and the raw material SC are mixed only in the processing space Fa. be able to. As a result, even if the raw material SC has a high reactivity with the reducing gas Gr, the reaction related to the raw material SC can be advanced only in the processing space Fa.

  In the middle of the raw material gas line Ls, a bypass line Lb leading to the raw material trap T is connected. When supplying the raw material SC toward the processing space Fa, the raw material supply unit SU closes the supply valve V3 until the supply amount of the raw material SC is stabilized, and opens the switching valve V4 to supply the raw material SC and the carrier gas. It leads to the raw material trap T through this bypass line Lb. When the supply amount of the raw material SC is stabilized, the raw material supply unit SU closes the switching valve V4 and opens the supply valve V3 to supply the raw material SC and the carrier gas to the processing space Fa. Thereby, the raw material supply unit SU can make the response of the supply and stop of the raw material SC to the processing space Fa steep.

When the transfer chamber FT carries the substrate S into the processing space Fa, the Ru chamber F1 places the substrate S on the stage 23 and puts the substrate S at a predetermined temperature (for example, 150 ° C. to 500 ° C.) via the heater H. The temperature rises to The Ru chamber F1 starts a thermal decomposition reaction of the raw material SC by heating at 150 ° C. or higher, and avoids thermal damage to lower conductors such as lower wiring by controlling the temperature at 500 ° C. or lower.

The Ru chamber F1 supplies the reducing gas Gr to the processing space Fa through the gas line Lr when the transfer chamber FT carries the substrate S into the processing space Fa, and also controls the pressure of the processing space Fa through the exhaust unit PU. Adjust to 10 ² Pa to 10 ⁵ Pa. The Ru chamber F1 sufficiently exhibits the reducing ability of the reducing gas Gr by the atmosphere containing the reducing gas Gr of 10 ² Pa or more, and avoids an excessive load exerted on the exhaust unit PU by the atmosphere of 10 ⁵ Pa or less. To do.

  The Ru chamber F1 supplies the raw material SC to the processing space Fa through the raw material gas line Ls when the atmosphere of the reducing gas Gr is formed in the processing space Fa, and thermally decomposes the raw material SC in the reducing gas Gr atmosphere. A Ru film is deposited on the substrate S by the reaction. Thereby, even if the surface of the substrate S exposes the lower layer conductor, the Ru chamber F1 can avoid oxidation of the lower layer conductor due to the atmosphere of the reducing gas Gr in the processing space Fa. The lower conductor and the Ru film can be connected without generating an oxide film between the Ru film and the lower conductor.

The oxidation chamber F2 is a chamber having substantially the same configuration as the Ru chamber F1, and is different from the Ru chamber F1 in that it does not include the raw material supply unit SU. Further, the oxidation chamber F2 is an oxidizing gas with respect to the mass flow controller MFC1. It differs in that Gox is supplied. As the oxidizing gas Gox, a gas containing oxygen (O ₂ ) or water (H ₂ O), or the atmosphere can be used.

When the substrate S having the Ru film is carried into the corresponding processing space Fa, the oxidation chamber F2 supplies the oxidizing gas Gox to the processing space Fa through the gas line Lr, and the pressure of the processing space Fa is set to a predetermined pressure ( For example, it adjusts to 10 < ² > Pa-10 < ⁶ > Pa). The oxidation chamber F2 places the substrate S on the stage 23 and adjusts the temperature of the substrate S to a predetermined temperature (for example, 20 ° C. to 500 ° C.) by driving the heater H.

When oxygen (O ₂ ) or water (H ₂ O) is used as the oxidizing gas Gox, the oxidation chamber F2 adjusts the partial pressure of oxygen (O ₂ ) or the partial pressure of water to 10 ² Pa to 10 ⁶ Pa. And the temperature of the board | substrate S is adjusted to 20 to 500 degreeC. Alternatively, the oxidation chamber F2 adjusts the humidity of the atmosphere to 20% to 100% and adjusts the temperature of the substrate S to 20 ° C. to 500 ° C. when the atmosphere is used as the oxidizing gas Gox. As a result, the oxidation chamber F2 sufficiently exhibits the oxidizing ability of the oxidizing gas Gox with respect to the organic matter contained in the Ru film, and suppresses excessive oxidation of Ru.

  The reduction chamber F3 is a chamber having substantially the same configuration as the Ru chamber F1, and is different from the Ru chamber F1 in that it does not include the raw material supply unit SU. The reduction chamber F3 is a chamber having substantially the same configuration as the oxidation chamber F2, and is different from the oxidation chamber F2 in that the reducing gas Gr is supplied to the mass flow controller MFC1. As the reducing gas Gr, a gas species can be used as in the Ru chamber F1.

The reduction chamber F3 supplies the reducing gas Gr to the processing space Fa through the gas line Lr when the substrate S subjected to the oxidation treatment is carried into the corresponding processing space Fa, and sets the pressure of the processing space Fa to a predetermined value. The pressure is adjusted (for example, 10 ⁻¹ Pa to 10 ⁶ Pa). The reduction chamber F3 places the substrate S on the stage 23 and adjusts the temperature of the substrate S to a predetermined temperature (for example, 150 ° C. to 500 ° C.) by driving the heater H.

The reducing chamber F3 sufficiently develops the reducing ability of the reducing gas Gr to the Ru film by the atmosphere containing the reducing gas Gr of 10 ⁻¹ Pa or more and the substrate temperature of 150 ° C. or more. Further, the reduction chamber F3 avoids an excessive load exerted on the exhaust unit PU by an atmosphere of 10 ⁶ Pa or less containing the reducing gas Gr, and by controlling the temperature of 500 ° C. or less, the substrate S, the lower layer wiring, etc. Avoid thermal damage.

In the present embodiment, the oxidation process and the reduction process that are continuous from the Ru film forming process are referred to as post-processing.
Next, an electrical configuration of the semiconductor device thin film forming apparatus 10 will be described below. FIG. 3 is an electric block circuit diagram showing an electrical configuration of the thin film forming apparatus 10.

  In FIG. 3, the control device 30 causes the thin film forming apparatus 10 to perform various processing operations, for example, transfer processing of the substrate S, Ru film formation processing, Ru film oxidation processing, Ru film reduction processing, and the like. It is. The control device 30 includes an input I / F 30A for inputting various signals, an arithmetic unit 30B for executing various arithmetic processes, a storage unit 30C for storing various data and various control programs, Output I / F 30D for outputting the above signal.

In the storage unit 30C, the number of Ru film formation processes is stored as the target film formation number NDp, and the number of post-processes executed for each film formation process is stored as the target post-process number NTp.
An input unit 31A, an LL chamber detection unit 32A, a transfer chamber detection unit 33A, a Ru chamber detection unit 34A, an oxidation chamber detection unit 35A, and a reduction chamber detection unit 36A are connected to the control device 30 via an input I / F 30A. Has been.

  The input unit 31 </ b> A includes various operation switches such as a start switch and a stop switch, and inputs data to be used by the thin film forming apparatus 10 for various processing operations to the control device 30. For example, the input unit 31 </ b> A inputs data related to the substrate S transfer process, the Ru film formation process, the Ru film oxidation process, and the Ru film reduction process to the control device 30.

  That is, the input unit 31 </ b> A inputs data related to the transport path (processing order of various processes) of the substrate S to the control device 30. Further, the input unit 31A relates to film forming conditions (for example, the substrate temperature, the flow rate of the reducing gas Gr, the supply amount of the raw material SC, the film forming pressure, the film forming time, etc.) for executing the Ru film forming process Data is input to the control device 30. In addition, the input unit 31 </ b> A inputs data regarding processing conditions (for example, the substrate temperature, the flow rate of the oxidizing gas Gox, the process pressure, the processing time, and the like) for executing the oxidation processing to the control device 30. Further, the input unit 31A inputs data related to processing conditions (for example, the substrate temperature, the flow rate of the reducing gas Gr, the process pressure, the processing time, etc.) for executing the reduction process to the control device 30. Further, the input unit 31A inputs data related to the target film formation number NDp and data related to the target post-processing number NTp.

The control device 30 receives various data input from the input unit 31A, stores it in the storage unit 30C, and executes various processing operations under conditions corresponding to the various data.
The LL chamber detection unit 32 </ b> A detects the state of the LL chamber FL, for example, the actual pressure in the storage chamber FLa, the number of substrates S to be stored, and inputs the detection result to the control device 30. The transfer chamber detection unit 33A detects the state of the transfer chamber FT, for example, the arm position of the transfer robot RB, and inputs the detection result to the control device 30.

  The Ru chamber detector 34A determines the state of the Ru chamber F1, for example, the actual temperature of the corresponding substrate S, the actual pressure of the processing space Fa, the actual flow rate of the reducing gas Gr, the actual supply amount of the raw material SC, the actual processing time, and the like. The detection result is input to the control device 30.

  The oxidation chamber detection unit 35A detects the state of the oxidation chamber F2, for example, the actual temperature of the corresponding substrate S, the actual pressure of the processing space Fa, the actual flow rate of the oxidizing gas Gox, the actual processing time, and the like. Input to the control device 30.

  The reduction chamber detection unit 36A detects the state of the reduction chamber F3, for example, the actual temperature of the corresponding substrate S, the actual pressure of the processing space Fa, the actual flow rate of the reducing gas Gr, the actual processing time, etc. Input to the control device 30.

  An output unit 31B, an LL chamber drive unit 32B, a transfer chamber drive unit 33B, a Ru chamber drive unit 34B, an oxidation chamber drive unit 35B, and a reduction chamber drive unit 36B are connected to the control device 30 via an output I / F 30D. Has been.

The output unit 31B includes various display devices such as a liquid crystal display and outputs various data related to the processing status of the thin film forming apparatus 10.
The control device 30 uses the detection signal from the LL chamber detection unit 32A to output a drive control signal corresponding to the LL chamber drive unit 32B to the LL chamber drive unit 32B. The LL chamber drive unit 32B responds to a drive control signal from the control device 30, and allows the substrate S to be loaded or unloaded by depressurizing or opening the accommodation chamber FLa.

  The control device 30 uses the detection signal from the transfer chamber detection unit 33A and outputs a drive control signal corresponding to the transfer chamber detection unit 33A based on the data related to the processing order input from the input unit 31A. Output to. The transfer chamber driving unit 33B responds to the drive control signal from the control device 30 and transfers the substrate S to the LL chamber FL, the transfer chamber FT, the Ru chamber F1, the oxidation chamber F2, and the reduction chamber F3 according to the Ru film formation program. Transport in order. Further, the transfer chamber driving unit 33B repeats the transfer process of the substrate S by the number of times of the target post-processing number NTp between the oxidation chamber F2 and the reduction chamber F3. Further, the transfer chamber driving unit 33B repeats the transfer process of the substrate S as many times as the target number of film formation NDp between the Ru chamber F1 and the reduction chamber F3.

  The control device 30 uses the detection signal from the Ru chamber detection unit 34A, and outputs a drive control signal corresponding to the Ru chamber drive unit 34B based on the Ru film formation condition input from the input unit 31A to the Ru chamber drive. To the unit 34B. In response to the drive control signal from the control device 30, the Ru chamber drive unit 34B executes the film formation process for the substrate S under the Ru film formation conditions input from the input unit 31A.

  The control device 30 uses the detection signal from the oxidation chamber detection unit 35A and outputs a drive control signal corresponding to the oxidation chamber drive unit 35B to the oxidation chamber drive unit 35B based on the oxidation condition input from the input unit 31A. To do. In response to the drive control signal from the control device 30, the oxidation chamber drive unit 35B executes the oxidation process of the Ru film under the oxidation conditions input from the input unit 31A.

  The control device 30 uses the detection signal from the reduction chamber detection unit 36A, and outputs a drive control signal corresponding to the reduction chamber drive unit 36B to the reduction chamber drive unit 36B based on the reduction condition input from the input unit 31A. To do. In response to the drive control signal from the control device 30, the reduction chamber drive unit 36B executes a reduction process of the Ru film under the reduction condition input from the input unit 31A.

Next, a thin film forming method using the thin film forming apparatus 10 will be described below. FIG. 4 is a flowchart showing a thin film forming method.
First, the control device 30 receives an operation signal for starting a film forming process, and performs the number of post-processing executed (hereinafter simply referred to as the actual post-processing number NTa) and the number of executed film forming processes (hereinafter referred to as the number of film forming processes). Simply, “0” is set to the actual number of film formations NDa) (step S11). Next, the control device 30 inputs the substrate S into the LL chamber FL and receives various data input from the input unit 31A (step S12). Then, the control device 30 detects the state of the LL chamber FL and the state of the transfer chamber FT, and starts the transfer process of the substrate S according to the target post-processing number NTp and the target film formation number NDp from the input unit 31A.

  That is, the control device 30 transports the substrate S of the LL chamber FL to the Ru chamber F1, and forms an atmosphere of the reducing gas Gr in the corresponding processing space Fa based on the film forming conditions from the input unit 31A. Further, the control device 30 drives the heater H of the Ru chamber F1 to raise the temperature of the substrate S, and then supplies the corresponding raw material SC to execute the Ru film forming process. Then, the control device 30 detects the state of the Ru chamber F1 and determines whether or not the Ru film formation process is completed. When the Ru film formation process is completed, the control apparatus 30 sets the actual number of film formation times NDa to “1”. "Is added to update the actual number of film formations NDa (step S13).

  When the Ru film formation process is completed, the controller 30 transfers the substrate S in the Ru chamber F1 to the oxidation chamber F2. The control device 30 forms an atmosphere of the oxidizing gas Gox in the corresponding processing space Fa based on the oxidation condition from the input unit 31A, and raises the temperature of the substrate S for a predetermined processing time to perform the oxidation treatment of the Ru film. It is executed (step s14).

  The control device 30 detects the state of the oxidation chamber F2 to determine whether or not the oxidation process is completed. When the oxidation process of the Ru film is completed, the substrate S in the oxidation chamber F2 is transferred to the reduction chamber F3. Based on the reduction condition from the input unit 31A, the control device 30 forms an atmosphere of the reducing gas Gr in the corresponding processing space Fa, raises the temperature of the substrate S for a predetermined processing time, and performs the reduction process of the Ru film. Let it run. Then, the control device 30 detects the state of the reduction chamber F3 to determine whether or not the reduction process of the Ru film is finished. When the reduction process of the Ru film is finished, “1” is set to the actual post-processing number NTa. In addition, the actual post-processing count NTa is updated (step S15).

  When updating the actual post-processing number NTa, the control device 30 determines whether or not the actual post-processing number NTa has reached the target post-processing number NTp, and until the actual post-processing number NTa reaches the target post-processing number NTp. Then, the oxidation process and the reduction process are repeatedly executed (NO in step S16).

  When the actual post-processing number NTa reaches the target post-processing number NTp, the control device 30 determines whether or not the actual film-forming number NDa has reached the target film-forming number NDp. The film formation process and the post-process are repeatedly executed until the number of times NDp is reached (NO in step S17).

Then, when the actual number of film formation NDa reaches the target number of film formation NDp, the control device 30 transfers the corresponding substrate S from the reduction chamber F3 to the LL chamber FL.
Thereafter, similarly, the control device 30 executes the post-processing of the target post-processing number NTp and the film-forming processing of the target film-forming number NDp for each of all the substrates S, and thereby the Ru film having a predetermined film thickness. To form. Then, when the controller 30 detects the state of the LL chamber FL and forms Ru films on all the substrates S, the controller 30 opens the LL chamber FL to the atmosphere and carries out all the substrates S to the outside.

(Example: Embeddability)
Next, the embedding property of the Ru film formed using the thin film forming apparatus 10 will be described below with reference to examples. FIG. 5 is a TEM (Transmission Electron Microscope) cross-sectional image showing the embedding property of the Ru film.

  First, a silicon substrate is used as the substrate S, and an insulating layer 41 having a thickness of 480 nm is formed on the substrate S. The insulating layer 41 has a hole diameter of 80 nm and an aspect ratio (hole depth / hole diameter) of 5.8. Hole VH (concave portion) was formed. Next, the Ru film 42 was formed on the surface of the insulating layer 41 using the following Ru film formation conditions, Ru film oxidation conditions, and Ru film reduction conditions, and an example was obtained.

(Ru film formation conditions)
Raw material SC: 0.5 (mol / L) bis (2-methoxyxy-6-methyl-3,5-heptanedionato) -1,5 hexadiene ruthenium complex using n-octane as a solvent. 0.2 (g / min)
・ Reducing gas Gr: flow rate of hydrogen and reducing gas Gr: 3 (L / min)
-Substrate temperature: 270 (° C)
-Film formation pressure: 2500 (Pa)
・ Deposition time: 720 (seconds)
-Target number of film formation NDp: 1
(Ru film oxidation conditions)
・ Oxidizing gas: 30% humidity atmosphere ・ Processing pressure: 1 atm ・ Processing temperature: 20 (℃)
・ Processing time: 300 (seconds)
(Reduction conditions for Ru film)
・ Reducing gas: Hydrogen ・ Processing pressure: 3500 (Pa)
・ Processing temperature: 310 (℃)
・ Processing time: 600 (seconds)
-Target post-processing number NTp: 1
In FIG. 5, it can be seen that the Ru film 42 is shown in a dark color region and is formed substantially uniformly with a film thickness of about 20 nm over the upper portion of the insulating layer 41 and the entire inner wall of the hole VH. Thus, according to the Ru film forming process, the oxidizing process, and the reducing process, even if the base is the insulating layer 41, the Ru film 42 having high film thickness uniformity and high step coverage can be obtained. I understand that.

(Example: resistivity)
Next, the resistivity of the Ru film formed using the thin film forming apparatus 10 will be described below with reference to examples. FIG. 6 is a diagram showing the resistivity of the Ru film.

  First, a silicon substrate is used as the substrate S, an insulating layer 41 having a film thickness of 100 nm is formed on the substrate S, and the following Ru film formation conditions, Ru film oxidation conditions, and Ru film reduction conditions are set. Using this, a Ru film 42 was formed on the surface of the insulating layer 41 to obtain an example.

(Ru film formation conditions)
Raw material SC: 0.5 (mol / L) bis (2-methoxyxy-6-methyl-3,5-heptanedionato) -1,5 hexadiene ruthenium complex using n-octane as a solvent. 0.2 (g / min)
・ Reducing gas Gr: flow rate of hydrogen and reducing gas Gr: 3 (L / min)
-Substrate temperature: 310 (° C)
-Film formation pressure: 3500 (Pa)
・ Deposition time: 140 (seconds)
-Target number of film formation NDp: 1
(Ru film oxidation conditions)
・ Oxidizing gas: 30% humidity atmosphere ・ Processing pressure: 1 atm ・ Processing temperature: 20 (℃)
・ Processing time: 300 (seconds)
(Reduction conditions for Ru film)
・ Reducing gas: Hydrogen ・ Processing pressure: 3500 (Pa)
・ Processing temperature: 310 (℃)
・ Processing time: 0 to 1800 (seconds)
-Target post-processing number NTp: 1
In addition, a comparative example was obtained by changing to a condition in which the oxidation treatment of the Ru film was not performed and the other conditions were the same as in the example. And the resistance value of each Ru film | membrane of an Example and a comparative example was measured. The resistance values of the example and the comparative example are shown in FIG.

In the example of FIG. 6, when the processing time of the reduction process is 0 (seconds), the resistance value is about 6 × 10 ³ (μΩ · cm), which is substantially the same value as the comparative example. . In the example, when the processing time of the reduction process is 300 (seconds) and 600 (seconds), the resistance value decreases to about 2 × 10 ² (μΩ · cm), which is one digit higher than that of the comparative example. It can be seen that the resistance value is also low. As a result, it is understood that the resistance value of the Ru film can be reduced by the post-processing (oxidation process + reduction process) applied to the Ru film.

(Method for manufacturing semiconductor device)
Next, a method for manufacturing a semiconductor device using the thin film forming method will be described below. FIG. 6 is a cross-sectional view of a principal part showing the semiconductor device.

  In FIG. 7, a semiconductor device 50 is, for example, a memory device including various RAMs and various ROMs, a logic device including an MPU or general-purpose logic, or the like. A plurality of thin film transistors Tr are formed on the substrate S of the semiconductor device 50, and a gate electrode 51 is provided in each of the plurality of thin film transistors Tr. Each gate electrode 51 is an electrode containing Ru as a main component, and is formed by the Ru film formation process using the Ru chamber F1, the oxidation process using the oxidation chamber F2, and the reduction process using the reduction chamber F3. . As a result, the thin film transistor Tr can reduce the resistance of the gate electrode 51 and improve the reliability thereof.

A capacitor 52 is connected to the diffusion layer LD of the thin film transistor Tr via a contact plug Pc. The capacitor 52 includes an upper electrode 52a, a lower electrode 52b, and a capacitor insulating layer 52c sandwiched between the upper electrode 52a and the lower electrode 52b. The upper electrode 52a and the lower electrode 52b are electrodes containing Ru as a main component, and are formed by the Ru film formation process, the oxidation process, and the reduction process, respectively. As the capacitor insulating layer 52c, for example, a ferroelectric such as (Ba, Sr) TiO ₂ or Pb (Zr, Ti) O ₃ can be used. As a result, the capacitor 52 can reduce the contact resistance between the lower electrode 52b and the contact plug Pc and the contact resistance between the capacitor insulating layer 52c and the upper electrode 52a, thereby improving the reliability. Can be made.

A wiring 53 is connected to the diffusion layer LD of the thin film transistor Tr via a contact plug Pc. The wiring 53 includes a base layer 53a connected to the contact plug Pc and a wiring layer 53b filling the inside of the base layer 53a. The underlayer 53a is a layer containing Ru as a main component, and is formed by the Ru film deposition process, oxidation process, and reduction process. As a result, the wiring 53 can be reduced in resistance and improved in reliability.

According to the said embodiment, there exist the following effects.
(1) In the above embodiment, the thin film forming apparatus 10 conveys the Ru film formed in the Ru chamber F1 to the oxidation chamber F2, exposes the Ru film to the atmosphere of the oxidizing gas Gox, and oxidizes the Ru film. Apply. Further, the thin film forming apparatus 10 transports the oxidized Ru film to the reduction chamber F3, exposes the Ru film to the atmosphere of the reducing gas Gr, and performs the reduction process on the Ru film. Therefore, the resistance of the Ru film can be reduced, and the reliability of the semiconductor device 50 including the Ru film can be improved.

  (2) In the above embodiment, the thin film forming apparatus 10 repeats the Ru film oxidation process and the Ru film reduction process by the target post-processing number NTp. In addition, the thin film forming apparatus 10 repeats the Ru film formation process and the Ru film post-process by the target number of film formation NDp. Therefore, a Ru film having a low resistance value can be laminated by repeating each process. Therefore, the resistance of the Ru film can be reduced regardless of the film thickness.

  (3) In the above embodiment, in the oxidation process, the partial pressure of the oxidizing gas Gox and the range of the substrate temperature are defined. Thereby, higher reproducibility can be given to the oxidation treatment of the Ru film, and excessive oxidation can be suppressed. Further, in the oxidation treatment of the Ru film, the load on the exhaust unit PU can be reduced, and thermal and mechanical damage to the substrate S can be avoided.

  (4) In the above embodiment, in the reduction process, the partial pressure of the reducing gas Gr and the range of the substrate temperature are defined. Thereby, higher reproducibility can be given to the reduction treatment of the Ru film. Further, in the reduction process of the Ru film, the load on the exhaust unit PU can be reduced, and thermal and mechanical damage to the substrate S can be avoided.

  (5) In the above embodiment, the thin film forming apparatus 10 includes an organoruthenium complex in an atmosphere of the reducing gas Gr, that is, a β-diketone having an alkoxyalkylmethyl group represented by the general formula (1) and 1,5-hexadiene. An Ru film is formed by thermal decomposition of the ruthenium complex. Therefore, oxidation of the underlayer can be avoided in the Ru film formation process, and as a result, the resistance of the stacked film including the Ru film can be reduced.

In addition, you may change the said embodiment into the following aspects.
In the above embodiment, the thin film forming apparatus 10 includes the oxidation chamber F2 for performing the oxidation process, and includes the oxidation chamber detection unit 35A and the oxidation chamber driving unit 35B. Further, the thin film forming apparatus 10 is equipped with a reduction chamber F3 for performing a reduction process, and includes a reduction chamber detection unit 36A and a reduction chamber drive unit 36B. For example, the thin film forming apparatus 10 has a configuration in which the oxidation chamber F2 or the reduction chamber F3 is not mounted, and the oxidation chamber detection unit 35A and the oxidation chamber drive unit 35B or the reduction chamber detection unit 36A and The reduction chamber driving unit 36B may not be included.

  That is, the thin film forming apparatus 10 is configured only by the Ru chamber F1, and is configured to be able to supply the oxidizing gas Gox and the reducing gas Gr to the Ru chamber F1. The Ru chamber F1 may be configured to perform Ru film formation processing, oxidation processing, and reduction processing.

Further, the Ru film formed in the Ru chamber F1 is transferred to the LL chamber FL, and the Ru film
The structure may be such that the oxidation treatment is performed by releasing the film to the atmosphere.
In the above embodiment, the Ru chamber F1 guides the raw material SC and the reducing gas Gr to the processing space Fa through independent paths. Not limited to this, when mixing of the raw material SC and the reducing gas Gr is allowed in the region excluding the processing space Fa, for example, when the reactivity between the raw material SC and the reducing gas Gr is low, the Ru chamber F1 may configure the first port P1 and the second port P2 as one common port. Further, the first supply hole K1 and the second supply hole K2 may be configured as supply holes that communicate with each other, and the reducing gas Gr may be used as a carrier gas for the mass flow controller MFC3.

  That is, the thin film forming method is not limited with respect to the supply path of the raw material SC and the reducing gas Gr, and may be configured to thermally decompose the raw material SC under the processing space Fa in a reducing atmosphere.

  In the above embodiment, the Ru film reduction process is performed following the Ru film oxidation process. However, the present invention is not limited to this, and heat treatment or the like for heating the Ru film between the Ru film oxidation process and the reduction process. The structure which performs another process may be sufficient.

  In the above embodiment, the raw material supply unit SU derives the raw material SC of the raw material tank 25 by pressurizing the derived gas, and supplies the gas of the raw material SC to the processing space Fa by vaporization of the vaporizer IU. For example, the raw material supply unit SU uses a so-called bubbling method in which a carrier gas is introduced into the raw material SC of the raw material tank 25 and a mixed gas of the carrier gas and the raw material SC is supplied to the processing space Fa. It may be.

  In the above embodiment, the Ru film is formed using the organic ruthenium complex and the reducing gas Gr. However, the present invention is not limited to this, and the Ru film may be formed without using the reducing gas Gr. Furthermore, the Ru film may be formed using a raw material different from the organic ruthenium complex.

The reducing gas Gr of the above embodiment is one that releases hydrogen radicals or hydrogen ions by separation, or hydrogen (H ₂ ), ammonia (NH ₃ ), hydrazine derivatives, silane (SiH ₄ ), disilane (Si ₂ H ₆ ) is embodied in at least one selected from the group consisting of. The reducing gas Gr is not limited to this, and any reducing gas may be used as long as it exhibits reducing ability to the raw material SC or reducing ability to the Ru film after the oxidation treatment.

  In the above embodiment, oxygen, water, or air is used as the oxidizing gas. However, the present invention is not limited to this, and a mixed gas of these may be used, and an oxidizing ability is expressed with respect to organic substances contained in the Ru film. Anything to do.

  In the above embodiment, the pressure and temperature during Ru film formation, the pressure and temperature during oxidation, and the pressure and temperature during reduction may be appropriately changed according to the film characteristics of the Ru film. That is, this thin film forming method includes a step of forming a Ru film on an object, a step of exposing the Ru film to an oxidizing gas atmosphere, and a step of exposing the Ru film to a reducing gas atmosphere. If it is good.

The top view which shows a thin film forming apparatus typically. The schematic sectional drawing which shows the structure of Ru chamber. The electric block circuit diagram which shows the electric constitution of a thin film forming apparatus. The flowchart which shows a thin film formation method. A TEM cross-sectional image showing the embedding property of a Ru film. The figure which shows the resistivity of Ru film | membrane. FIG. 6 is a cross-sectional view of a main part showing a semiconductor device.

Explanation of symbols

Fa ... processing space, Gr ... reducing gas, Gox ... oxidizing gas, S ... substrate, SU ... raw material supply unit, 42 ... ruthenium film, 50 ... semiconductor device.

Claims (15)

An organic ruthenium complex represented by the general formula (1) (wherein R ¹ represents a linear or branched alkyl group having 1 to 4 carbon atoms) and a first reducing gas are added to the object. Using the step of forming a ruthenium-containing film,
Exposing the ruthenium-containing film to an oxidizing gas atmosphere;
And a step of exposing the ruthenium-containing film to an atmosphere of a second reducing gas.
The thin film forming method according to claim 1,
The organic ruthenium complex is a bis (2-methoxyxy-6-methyl-3,5-heptanedionato) -1,5 hexadiene ruthenium complex. The thin film forming method according to claim 1 or 2,
Following the step of exposing the ruthenium-containing film to the oxidizing gas atmosphere, performing a step of exposing the ruthenium-containing film to the second reducing gas atmosphere;
A method for forming a thin film. A thin film forming method according to any one of claims 1 to 3,
Repeating the steps of forming the ruthenium-containing film, exposing the ruthenium-containing film to the oxidizing gas atmosphere, and exposing the ruthenium-containing film to the second reducing gas atmosphere;
A method for forming a thin film. A thin film forming method according to any one of claims 1 to 4,
The atmosphere of the oxidizing gas contains oxygen (O ₂ );
A method for forming a thin film. The thin film forming method according to claim 5,
The step of exposing to the oxidizing gas atmosphere includes:
The partial pressure of oxygen (O ₂ ) is 10 ² Pa to 10 ⁶ Pa,
The temperature of the object is 20 ° C to 500 ° C,
A method for forming a thin film. A thin film forming method according to any one of claims 1 to 4,
The atmosphere of the oxidizing gas contains water (H ₂ O);
A method for forming a thin film. The thin film forming method according to claim 7,
The step of exposing to the oxidizing gas atmosphere includes:
The partial pressure of water (H ₂ O) is 10 ² Pa to 10 ⁶ Pa,
The temperature of the object is 20 ° C to 500 ° C,
A method for forming a thin film. A thin film forming method according to any one of claims 1 to 4,
The atmosphere of the oxidizing gas is air,
A method for forming a thin film. The thin film forming method according to claim 9,
The step of exposing to the oxidizing gas atmosphere includes:
The atmospheric humidity is 20% to 100%,
The temperature of the object is 20 ° C to 500 ° C,
A method for forming a thin film. A thin film forming method according to any one of claims 1 to 10,
The second reducing gas dissociates to release hydrogen radicals and hydrogen ions;
A method for forming a thin film. A thin film forming method according to any one of claims 1 to 10,
The second reducing gas is at least one selected from the group consisting of hydrogen (H ₂ ), ammonia (NH ₃ ), a hydrazine derivative, silane (SiH ₄ ), and disilane (Si ₂ H ₆ ). thing,
A method for forming a thin film. The thin film forming method according to claim 12,
The hydrazine derivative is obtained by substituting one or two hydrogen atoms of hydrazine with a group selected from the group consisting of a methyl group, an ethyl group, and a linear or branched butyl group,
A method for forming a thin film. A thin film forming method according to any one of claims 1 to 13,
The step of exposing to the second reducing gas atmosphere includes:
Setting the atmosphere of the second reducing gas to 10 ⁻¹ Pa to 10 ⁶ Pa;
A method for forming a thin film. A thin film forming method according to any one of claims 1 to 14,
The step of forming the ruthenium-containing film includes
Setting the temperature of the object to 150 ° C. to 500 ° C.,
A method for forming a thin film.