JP2010212323A - METHOD OF FORMING Cu FILM, AND STORAGE MEDIUM - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming a Cu film in which a smooth CVD-Cu film of high quality can be formed with high adhesion to a substrate. <P>SOLUTION: In the method of forming the Cu film, the temperature of a wall part of a chamber 1 is controlled to equal to or higher than a temperature at which the vapor pressure of Cu(hfac)<SB>2</SB>as a by-product produced during film formation becomes equal to the pressure in the chamber 1 and lower than the decomposition temperature of Cu(hfac)TMVS as a film forming material when the Cu film is formed on an Ru film by a CVD method by storing a wafer W having a CVD-Ru film in the chamber 1, and introducing, into the chamber 1, the film forming material made of the Cu(hfac)TMVS as a Cu complex such that the vapor pressure of Cu(hfac)<SB>2</SB>as the by-product is lower than its vapor pressure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a Cu film forming method and a storage medium for forming a Cu film on a substrate such as a semiconductor substrate by CVD.

  Recently, Cu has higher conductivity than Al and better electromigration resistance in response to higher speeds of semiconductor devices, finer wiring patterns, etc. Materials for wiring, Cu plating seed layers, and contact plugs It is attracting attention as.

  As a Cu film forming method, a physical vapor deposition (PVD) method typified by sputtering has been frequently used. However, a defect that the step coverage is poor with the miniaturization of a semiconductor device has become apparent.

Therefore, as a method for forming a Cu film, there is a chemical vapor deposition (CVD) method in which Cu is formed on a substrate by a thermal decomposition reaction of a source gas containing Cu or a reduction reaction of the source gas with a reducing gas. It is being used. A Cu film (CVD-Cu film) formed by such a CVD method has high step coverage (step coverage) and excellent film formability in a long and narrow pattern. The followability is high, and it is suitable for forming a wiring, a Cu plating seed layer, and a contact plug.

  In forming a Cu film by this CVD method, a technology is known in which a Cu complex such as hexafluoroacetylacetonate / trimethylvinylsilane copper (Cu (hfac) TMVS) is used as a film forming material (precursor) and thermally decomposed. (For example, Patent Document 1).

  On the other hand, a technique using a Ru film (CVD-Ru film) by a CVD method is known as a Cu adhesion layer or a barrier metal (Patent Document 2). A CVD-Ru film is suitable for a Cu adhesion layer or a barrier metal because it has high step coverage and high adhesion to a Cu film.

JP 2000-282242 A Japanese Patent Laid-Open No. 10-229084

  However, when a monovalent diketone complex such as Cu (hfac) TMVS described above is used as a film-forming raw material for the CVD-Cu film, the vapor pressure is higher than that of the film-forming raw material during the film formation of the CVD-Cu film. A low by-product is generated, and this by-product is adsorbed on the film formation surface. For this reason, the Ru film surface, which is the film formation surface, has a chemical activity that decreases due to poisoning, which causes inhibition of adsorption of the Cu raw material and a decrease in wettability between the Cu film and the Ru film. As a result, the initial nucleus density of Cu is lowered, the surface properties of the Cu film are deteriorated (roughened surface shape), the quality of the Cu film is lowered, and the adhesion between the Cu film and the Ru film is lowered. . Such a problem often occurs when a film other than the CVD-Ru film is used as the film formation surface.

The present invention has been made in view of such circumstances, and provides a Cu film forming method capable of forming a smooth and high-quality CVD-Cu film with high adhesion to a base. Objective.
It is another object of the present invention to provide a storage medium storing a program for executing such a film forming method.

  In the case where a film-forming raw material whose vapor pressure of the by-product is lower than the vapor pressure is used, the present inventors inhibit adsorption of the Cu raw material due to adsorption of the by-product and wettability between the Cu film and the base. The mechanism by which the decrease occurs was examined. As a result, a by-product having a vapor pressure lower than that of the film forming raw material is easily adsorbed on the wall of the processing container, and the by-product component adsorbed on the wall of the processing container is vaporized during film formation. A large amount of by-products are generated in the gas phase inside, and the large amount of by-products are adsorbed on the substrate surface, thereby inhibiting the adsorption of Cu raw material and reducing the wettability between the Cu film and the base. It has been found. As a result of further investigation based on this, the temperature of the wall of the processing container during film formation is higher than the temperature at which the vapor pressure of the by-product is equal to the pressure in the processing container during the film forming process. By controlling the temperature below the decomposition temperature, the adsorption of by-products to the inner wall of the processing vessel is prevented while suppressing the decomposition of the film forming raw material in the processing vessel, and the by-product adsorbed during the film formation is vaporized. The amount of by-products generated in the gas phase by decomposition of the film-forming raw material in the processing vessel can be suppressed, and the adsorption of the Cu raw material due to the by-product adsorbing to the base film on the substrate and The inventors have found that a decrease in wettability between the Cu film and the base is suppressed, and have completed the present invention.

  That is, according to the present invention, a substrate is accommodated in a processing container, and a film forming raw material composed of a Cu complex in which the vapor pressure of a by-product generated during film formation is lower than the vapor pressure is vapor-phased in the processing container. When the Cu film is formed on the substrate by CVD, the temperature of the wall of the processing container is set to a temperature at which the vapor pressure of the by-product becomes equal to the pressure in the processing container during the film forming process. The Cu film forming method is characterized by controlling the temperature below the decomposition temperature of the film forming raw material.

In the present invention, a monovalent β-diketone complex can be used as the Cu complex. Among them, hexafluoroacetylacetonate / trimethylvinylsilane copper (Cu (hfac) TMVS) can be mentioned as a suitable one, and the by-product is hexafluoroacetylacetonate copper (Cu (hfac) ₂ ). . In this case, the temperature of the wall portion of the processing container is preferably 75 ° C. or higher and lower than 100 ° C.

It is preferable to use a substrate having a Ru film formed on the surface by a CVD method, and form a Cu film on the Ru film. As the Ru film, a film formed using Ru ₃ (CO) ₁₂ as a film forming material is suitable. The Ru film can be used as all or part of the diffusion barrier film. In this case, the diffusion prevention film may have a refractory material film as a lower layer of the Ru film. As the refractory material film, a film made of any of Ta, TaN, Ti, W, TiN, WN, and manganese oxide can be used.

  The obtained Cu film may be used as a wiring material or a seed film for Cu plating.

  The present invention is also a storage medium that operates on a computer and stores a program for controlling the film forming apparatus, and the program is stored in the computer so that the film forming method is performed at the time of execution. A storage medium characterized by controlling a film formation apparatus is provided.

  According to the present invention, adsorption of by-products on the substrate surface can be suppressed, so that inhibition of adsorption of Cu raw material and reduction in wettability between the Cu film and the base can be suppressed. For this reason, a smooth and high-quality CVD-Cu film can be formed on the substrate with high adhesion.

1 is a schematic cross-sectional view showing an example of the configuration of a film forming apparatus that performs the Cu film forming method of the present invention. It is sectional drawing which shows the structure of the semiconductor wafer which is a board | substrate with which the film-forming method of Cu film | membrane of this invention is applied. It is a schematic diagram for demonstrating the state in the chamber in the film-forming method of the conventional Cu film | membrane. It is a schematic diagram for demonstrating the state in the chamber in the film-forming method of Cu film | membrane of this invention. It is sectional drawing which shows the state which formed the CVD-Cu film | membrane as a wiring material with respect to the semiconductor wafer of the structure of FIG. It is sectional drawing which shows the state which formed the CVD-Cu film | membrane as a seed film | membrane of Cu plating with respect to the semiconductor wafer of the structure of FIG. FIG. 6 is a cross-sectional view illustrating a state where CMP is performed on the semiconductor wafer having the structure of FIG. 5. It is sectional drawing which shows the state which gave Cu plating with respect to the semiconductor wafer of the structure of FIG. It is sectional drawing which shows the state which performed CMP with respect to the semiconductor wafer of the structure of FIG. It is sectional drawing which shows the other structure of the semiconductor wafer which is a board | substrate with which the film-forming method of Cu film | membrane of this invention is applied. It is a scanning microscope (SEM) photograph which shows Cu film | membrane formed into a film by the method of the Example. It is a scanning microscope (SEM) photograph which shows Cu film | membrane formed into a film by the method of the comparative example.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Configuration of film forming apparatus for carrying out the film forming method of the present invention>
FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a film forming apparatus for carrying out the film forming method of the present invention.
The film forming apparatus 100 includes a substantially cylindrical chamber 1 that is airtightly configured, and a susceptor 2 for horizontally supporting a semiconductor wafer W that is a substrate to be processed is provided at the lower center of the chamber. It arrange | positions in the state supported by the provided cylindrical support member 3. As shown in FIG. The susceptor 2 is made of a ceramic such as AlN. Further, a heater 5 is embedded in the susceptor 2, and a heater power source 6 is connected to the heater 5. On the other hand, a thermocouple 7 is provided in the vicinity of the upper surface of the susceptor 2, and a signal of the thermocouple 7 is transmitted to the heater controller 8. The heater controller 8 transmits a command to the heater power supply 6 in accordance with a signal from the thermocouple 7, and controls the heating of the heater 5 to control the wafer W to a predetermined temperature.

A circular hole 1 b is formed in the top wall 1 a of the chamber 1, and a shower head 10 is fitted so as to protrude into the chamber 1 therefrom. The shower head 10 is for discharging a film forming gas supplied from a gas supply mechanism 30 to be described later into the chamber 1, and is generated by thermal decomposition as a film forming raw material gas on the upper part thereof. First introduction in which a Cu complex in which the vapor pressure of the by-product is lower than the vapor pressure, for example, hexafluoroacetylacetonate-trimethylvinylsilane copper (Cu (hfac) TMVS), which is a monovalent β-diketone complex, is introduced. A passage 11 and a second introduction passage 12 through which dilution gas is introduced into the chamber 1 are provided. Ar gas or H ₂ gas is used as the dilution gas.

Inside the shower head 10, spaces 13 and 14 are provided in two upper and lower stages. A first introduction path 11 is connected to the upper space 13, and a first gas discharge path 15 extends from the space 13 to the bottom surface of the shower head 10. A second introduction path 12 is connected to the lower space 14, and a second gas discharge path 16 extends from the space 14 to the bottom surface of the shower head 10. That is, the shower head 10 is configured so that the Cu complex gas and the dilution gas as film forming materials are independently discharged from the discharge paths 15 and 16.

  An exhaust chamber 21 that protrudes downward is provided on the bottom wall of the chamber 1. An exhaust pipe 22 is connected to the side surface of the exhaust chamber 21, and an exhaust device 23 having a vacuum pump, a pressure control valve, and the like is connected to the exhaust pipe 22. By operating the exhaust device 23, the inside of the chamber 1 can be depressurized to a predetermined degree of vacuum.

  On the side wall of the chamber 1, a loading / unloading port 24 for loading / unloading the wafer W to / from a wafer transfer chamber (not shown) and a gate valve G for opening / closing the loading / unloading port 24 are provided.

  The gas supply mechanism 30 forms a Cu complex, for example, Cu (hfac) TMVS, which is a liquid monovalent β-diketone complex, in which the vapor pressure of a by-product generated by thermal decomposition is lower than the vapor pressure. It has the film-forming raw material tank 31 stored as a raw material. Other monovalent β-diketones such as Cu (hfac) MHY, Cu (hfac) ATMS, Cu (hfac) DMDVS, Cu (hfac) TMMOVS, Cu (hfac) COD, etc. are used as the Cu complex constituting the film forming raw material. Complexes can be used. When the monovalent Cu complex to be used is solid at room temperature, it can be stored in the film forming raw material tank 31 in a state dissolved in a solvent.

A pressure-feed gas pipe 32 for supplying a pressure-feed gas such as He gas is inserted into the film-forming raw material tank 31 from above, and a valve 33 is interposed in the pressure-feed gas pipe 32. In addition, a raw material delivery pipe 34 is inserted from above into the deposition raw material in the deposition raw material tank 31, and a vaporizer 37 is connected to the other end of the raw material delivery pipe 34. A valve 35 and a liquid mass flow controller 36 are interposed in the raw material delivery pipe 34. Then, by introducing the pressurized gas into the film forming raw material tank 31 through the pressure supplying gas pipe 32, the Cu complex, for example, Cu (hfac) TMVS in the film forming raw material tank 31 is supplied to the vaporizer 37 in a liquid state. The The liquid supply amount at this time is controlled by the liquid mass flow controller 36. The vaporizer 37 is connected to a carrier gas pipe 38 for supplying Ar or H ₂ or the like as a carrier gas. The carrier gas pipe 38 is provided with two valves 40 sandwiching the mass flow controller 39 and the mass flow controller 39. The vaporizer 37 is connected to a film forming material gas supply pipe 41 that supplies the vaporized Cu complex toward the shower head 10. A film forming source gas supply pipe 41 is provided with a valve 42, and the other end is connected to the first introduction path 11 of the shower head 10. Then, the Cu complex vaporized by the vaporizer 37 is carried by the carrier gas, sent to the film forming raw material gas supply pipe 41, and supplied from the first introduction path 11 into the shower head 10. A heater 43 for preventing condensation of the film forming raw material gas is provided in a portion to the vaporizer 37, the film forming raw material gas supply pipe 41 and the valve 40 on the downstream side of the carrier gas pipe. The heater 43 is supplied with power from a heater power source (not shown), and the temperature is controlled by a controller (not shown).

A dilution gas supply pipe 44 that supplies dilution gas is connected to the second introduction path 12 of the shower head 10. A valve 45 is interposed in the dilution gas supply pipe 44. Then, Ar gas or H ₂ gas is supplied as dilution gas from the second introduction path 12 into the shower head via the dilution gas supply pipe 44.

  A heater 46 is provided on the wall of the chamber 1, and a heater power supply 47 is connected to the heater 46. On the other hand, a thermocouple 48 is embedded in the wall portion of the chamber 1, and a signal of the thermocouple 48 is transmitted to the heater controller 49. Then, the heater controller 49 sends a command to the heater power supply 47 in accordance with the signal from the thermocouple 48, controls the heating of the heater 46, changes the temperature of the inner wall of the chamber 1, and the vapor pressure of the byproduct is during the film forming process. The temperature is controlled to a temperature equal to or higher than the pressure in the chamber 1 and higher than the vapor pressure temperature of the by-product in the chamber 1 during the film forming process and lower than the decomposition temperature of the film forming raw material.

  The film forming apparatus 100 includes a control unit 50, and the control unit 50 controls various components such as the heater power source 6, the exhaust device 23, the mass flow controllers 36 and 39, the valves 33, 35, 40, 42, and 45. Temperature control of the susceptor 2 through the heater controller 8, temperature control of the inner wall of the chamber 1 through the heater controller 49, and the like are performed. The control unit 50 includes a process controller 51 including a microprocessor (computer), a user interface 52, and a storage unit 53. Each component of the film forming apparatus 100 is electrically connected to the process controller 51 and controlled. The user interface 52 is connected to the process controller 51, and a keyboard on which an operator inputs commands to manage each component of the film forming apparatus 100, and operating status of each component of the film forming apparatus 100. It consists of a display etc. that visualizes and displays. The storage unit 53 is also connected to the process controller 51, and the storage unit 53 corresponds to a control program for realizing various processes executed by the film forming apparatus 100 under the control of the process controller 51 and processing conditions. A control program for causing each component of the film forming apparatus 100 to execute a predetermined process, that is, a process recipe, various databases, and the like are stored. The processing recipe is stored in a storage medium (not shown) in the storage unit 53. The storage medium may be a fixed medium such as a hard disk or a portable medium such as a CDROM, DVD, or flash memory. Moreover, you may make it transmit a recipe suitably from another apparatus via a dedicated line, for example.

  Then, if necessary, a predetermined processing recipe is called from the storage unit 53 by an instruction from the user interface 52 and executed by the process controller 51, so that the film forming apparatus 100 can control the process controller 51. Desired processing is performed.

<Method for Forming Cu Film According to Embodiment of the Present Invention>
Next, the Cu film forming method of the present embodiment using the film forming apparatus configured as described above will be described.

  Here, a case will be described as an example where Cu (hfac) TMVS is used as a film forming raw material in which the vapor pressure of a by-product generated during film formation is lower than the vapor pressure.

  Further, here, a Cu film (CVD-Cu film) is formed by the CVD method on the Ru film (CVD-Ru film) formed by the CVD method. For example, as illustrated in FIG. 2, an interlayer insulating film 105 is formed via a cap insulating film 104 on a lower wiring insulating layer 103 where a lower Cu wiring layer 101 is formed via a CVD-Ru film 102. An upper wiring insulating layer 107 is formed thereon via a hard mask layer 106, and penetrates the hard mask layer 106, the interlayer insulating film 105, and the cap insulating film 104, and reaches the lower Cu wiring layer 101. A trench 109 which is a wiring groove is formed in the upper wiring insulating layer 107, and a CVD-Ru film is formed as a barrier layer (diffusion prevention layer) on the inner wall of the via hole 108 and the trench 109 and on the upper wiring insulating layer 107. A CVD-Cu film is formed on the wafer W on which 110 is formed.

The CVD-Ru film is preferably formed using Ru ₃ (CO) ₁₂ as a film forming material. Thereby, since high purity CVD-Ru can be obtained, a clean and strong interface between Cu and Ru can be formed. The apparatus for forming the CVD-Ru film is the same as the apparatus of FIG. 1 except that steam generated by heating Ru ₃ (CO) ₁₂ that is solid at room temperature is supplied. Can be used.

When forming the Cu film, first, the gate valve G is opened, the wafer W having the above-described configuration is introduced into the chamber 1 by a transfer device (not shown), and placed on the susceptor 2. Next, the inside of the chamber 1 is evacuated by the exhaust device 23 so that the pressure in the chamber 1 is 1.33 to 266.6 Pa (10 mTorr to 2 Torr), the susceptor 2 is heated to 150 to 200 ° C. by the heater 5, and the carrier gas pipe 38, the vaporizer 37, the film forming raw material gas pipe 41, and the shower head 10 are used to supply a carrier gas into the chamber 1 at a flow rate of 100 to 1500 mL / min (sccm), and about 0 to 1500 mL / min (sccm). The dilution gas is introduced into the chamber 1 through the dilution gas supply pipe 44 and the shower head 10 for stabilization.

  When stabilization is performed for a predetermined time and the conditions are stabilized, liquid Cu (hfac) TMVS is vaporized by a vaporizer 37 at 50 to 70 ° C. in the chamber 1 while the carrier gas and the dilution gas are supplied. Then, Cu film formation is started. The flow rate at this time is about 100 to 500 mg / min as a liquid.

Cu (hfac) TMVS which is a film forming raw material is decomposed by the reaction shown in the following formula (1) on the wafer W which is a substrate to be processed heated by the heater 5 of the susceptor 2, and a Cu film is formed on the Ru film. Is deposited.
2Cu (hfac) TMVS → Cu + Cu (hfac) ₂ + 2TMVS (1)

By the way, Cu (hfac) ₂ generated as a by-product at this time has a lower vapor pressure than Cu (hfac) TMVS which is a film forming raw material. Therefore, when the temperature of the chamber 1 is low, it is easily adsorbed on the inner wall of the chamber 1. When film formation is performed with Cu (hfac) ₂ adsorbed on the inner wall of the chamber 1, the Cu (hfac) ₂ vaporized from the inner wall of the chamber 1 enters the gas phase in the chamber 1 as shown in FIG. 3. Will exist. Further, a part of Cu (hfac) TMVS supplied at the time of film formation is also decomposed in the gas phase to generate Cu (hfac) ₂ . For this reason, a large amount of Cu (hfac) ₂ exists in the gas phase in the chamber 1, and Cu (hfac) ₂ is adsorbed on the surface of the CVD-Ru film 110.

When Cu (hfac) ₂ is adsorbed on the surface of the CVD-Ru film 110 in this way, the chemical activity of the Ru film surface decreases due to poisoning, and the adsorption inhibition of Cu (hfac) TMVS and the Cu film and the Ru film. A decrease in wettability occurs. As a result, the initial nucleus density of Cu is lowered, the surface properties of the Cu film are deteriorated (roughened surface shape), the quality of the Cu film is lowered, and the adhesion between the Cu film and the Ru film is lowered. .

Therefore, in this embodiment, by heating the walls of the chamber 1 by the heater 46, the inner wall temperature T _W of the chamber 1, the temperature the vapor pressure of the by-products is equal to the pressure in the chamber 1 of the film forming process T The temperature is controlled to be _V or higher. However, if the temperature of the inner wall of the chamber 1 is Cu (hfac) TMVS decomposition temperature _{T D} above, Cu (hfac) TMVS ends up decomposing by the inner wall of the chamber 1 at the time of film formation, Cu MakuNaru of the wafer W surface The amount contributing to the membrane reaction is reduced. For this reason, the temperature of the inner wall of the chamber 1 is controlled to be lower than the decomposition temperature of Cu (hfac) TMVS. In other words, the _{T V ≦ T W <T D} .

Specifically, since the Cu _{(hfac) 2} is the pressure during film formation was vaporized at 75 ℃, Cu (hfac) TMVS decomposes at 100 ° C., a temperature _{T W} of the walls of the chamber 1,
75 ≦ T _W (° C.) <100
And

As a result, as shown in FIG. 4, the adsorption of Cu (hfac) ₂ to the inner wall of the chamber 1 is prevented while suppressing the decomposition of Cu (hfac) TMVS in the chamber 1, and the Cu ( hfac) ₂ is vaporized or Cu (hfac) TMVS is decomposed in the chamber 1 to suppress the amount of Cu (hfac) ₂ generated in the gas phase. For this reason, adsorption inhibition of Cu (hfac) TMVS and decrease in wettability between the Cu film and the Ru film due to adsorption of Cu (hfac) ₂ to the CVD-Ru film 110 are suppressed. Therefore, a smooth and high-quality CVD-Cu film can be formed on the CVD-Ru film 110 with high adhesion.

  At this time, a CVD-Cu film can be used as a wiring material, or can be used as a seed layer for Cu plating. When the CVD-Cu film is used as the wiring material, as shown in FIG. 5, the CVD-Cu film 111 is formed until all the via holes 108 and the trench 109 are filled, and all the wiring and plugs are formed in the CVD-Cu film 111. Form with. When used as a Cu plating seed film, a CVD-Cu film 111 is thinly formed on the surface of the CVD-Ru film 110 as shown in FIG.

Then, after forming the Cu film in this way, a purge process is performed. In the purge process, after the supply of Cu (hfac) TMVS is stopped, the vacuum pump of the exhaust device 23 is turned off, and the inside of the chamber 1 is purged by flowing the carrier gas into the chamber 1 as a purge gas. In this case, it is preferable to supply the carrier gas intermittently from the viewpoint of purging the inside of the chamber 1 as quickly as possible.

  After the purge process is completed, the gate valve G is opened, and the wafer W is unloaded through the loading / unloading port 24 by a transfer device (not shown). Thus, a series of steps for one wafer W is completed.

  When all the wirings and plugs are formed of the CVD-Cu film 111 as shown in FIG. 5, CMP (Chemical Mechanical Polishing) is then performed to remove excess Cu portions, and as shown in FIG. The film 107 and the CVD-Cu film 111 are flush with each other. When the CVD-Cu film 111 is thinly formed as a Cu plating seed film as shown in FIG. 6, the Cu plating 112 is then formed as shown in FIG. Then, CMP (Chemical Mechanical Polishing) is performed to remove an excessive Cu portion so that the wiring insulating film 107 and the Cu plating layer 112 are flush with each other as shown in FIG.

  In the above example, a single layer of the CVD-Ru film 110 is used as the barrier layer (diffusion prevention layer). However, as shown in FIG. 10, the upper CVD-Ru film 110 and the high layer as the lower layer are used. A laminated structure with the melting point material film 113 may be used. In this case, any of Ta, TaN, Ti, W, TiN, WN, manganese oxide, etc. can be used as the lower layer.

<Example>
Next, examples of the present invention will be described in comparison with comparative examples.
Here, a SiO ₂ film having a thickness of 100 nm is formed on a Si substrate, and a barrier layer made of a Ti film having a thickness of 2 nm and a CVD-Ru film having a thickness of 2 nm formed thereon by sputtering is formed. A Cu film was formed by the apparatus shown in FIG. 1 using Cu (hfac) TMVS as a film forming material as a substrate. While using Cu (hfac) TMVS as a film forming material and supplying it at a flow rate of 255 mg / min, H ₂ gas is supplied as a carrier gas at a flow rate of 400 mL / min (sccm), and the pressure in the chamber 1 is set to 13.3 Pa ( 0.1 Torr) was introduced into the chamber 1 at a susceptor temperature of 240 ° C., and the Cu film was formed at a temperature of the wall portion of the chamber 1 of 80 ° C. in the example and 60 ° C. in the comparative example. The surface states of the Cu films formed by Examples and Comparative Examples are shown by scanning microscope (SEM) photographs of FIGS. 11 and 12, respectively. As shown in these figures, in the comparative example of FIG. 12, the nuclei are sparse and the nuclear density is low, but in the example of FIG. 11, the nuclei are dense and the nuclear density is high. From this result, it was confirmed that the nuclear density in forming the Cu film can be increased by the present invention.

<Other applications of the present invention>
The present invention can be variously modified without being limited to the above embodiment. For example, in the above embodiment, the case where Cu (hfac) TMVS is used as the Cu complex whose vapor pressure of the by-product generated by thermal decomposition is lower than the vapor pressure is shown, but the present invention is not limited to this. is not. Further, although the case where a CVD-Ru film is used as a base for film formation is shown, the present invention is not limited to this.

  In the above embodiment, the liquid Cu complex is pumped and supplied to the vaporizer, and vaporized by the vaporizer. However, the present invention is not limited to this, and other methods such as vaporizing by bubbling or the like and supplying the other methods are available. You may vaporize with.

  Further, the film forming apparatus is not limited to the one in the above embodiment, and various apparatuses such as a mechanism provided with a plasma forming mechanism for promoting the decomposition of the film forming source gas can be used.

  Furthermore, the structure of the substrate to be processed is not limited to that shown in FIGS. Furthermore, although the case where the semiconductor wafer was used as a to-be-processed substrate was demonstrated, not only this but another board | substrate, such as a flat panel display (FPD) board | substrate, may be sufficient.

DESCRIPTION OF SYMBOLS 1; Chamber 2; Susceptor 3; Support member 5; Heater 10; Shower head 23; Exhaust device 30; Gas supply mechanism 31; Film formation raw material tank 34; Raw material delivery pipe 37; Film source gas supply pipe 46; heater 47; heater power supply 48; thermocouple 49; heater controller 50; control unit 51; process controller 52; user interface 53; storage unit (storage medium)
W: Semiconductor wafer

Claims (12)

  A substrate is accommodated in a processing container, and a film forming material composed of a Cu complex in which the vapor pressure of a by-product generated during film formation is lower than the vapor pressure is introduced into the processing container in a gas phase state. When forming a Cu film on a substrate by a CVD method, the temperature of the wall of the processing container is equal to or higher than the temperature at which the vapor pressure of the by-product is equal to the pressure in the processing container during the film forming process. A method for forming a Cu film, wherein the temperature is controlled to be lower than the decomposition temperature.   The Cu film forming method according to claim 1, wherein the Cu complex is a monovalent β-diketone complex. The Cu complex is hexafluoroacetylacetonate / trimethylvinylsilane copper (Cu (hfac) TMVS), and the by-product is hexafluoroacetylacetonate copper (Cu (hfac) ₂ ). The method for forming a Cu film according to claim 2.   The method of forming a Cu film according to claim 3, wherein the temperature of the wall portion of the processing container is 75 ° C or higher and lower than 100 ° C.   5. The method according to claim 1, wherein a substrate having a Ru film formed on the surface by a CVD method is used, and a Cu film is formed on the Ru film. A method for forming a Cu film according to the description. The Cu film forming method according to claim 5, wherein the Ru film is formed using Ru ₃ (CO) ₁₂ as a film forming material.   The Cu film forming method according to claim 5, wherein the Ru film is used as all or part of a diffusion preventing film.   8. The method of forming a Cu film according to claim 7, wherein the diffusion preventing film has a refractory material film as a lower layer of the Ru film.   9. The method of forming a Cu film according to claim 8, wherein the refractory material film is made of any one of Ta, TaN, Ti, W, TiN, WN, and manganese oxide.   The Cu film forming method according to any one of claims 1 to 9, wherein the obtained Cu film is used as a wiring material.   The method for forming a Cu film according to claim 1, wherein the obtained Cu film is used as a seed film for Cu plating.   A storage medium that operates on a computer and stores a program for controlling a film forming apparatus, wherein the program performs the film forming method according to any one of claims 1 to 11 at the time of execution. And a computer that controls the film forming apparatus.