JP2008244420A - Apparatus for forming conductor, method for forming conductor, and method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for forming a conductor, which can improve its controllability when forming a conductor in a fine hole, groove, recess, or the like with a high aspect ratio by the use of a supercritical fluid. <P>SOLUTION: A conductor forming apparatus 1 is composed of a reaction container 2, a supply device 3, a discharge device 4, and the like. A process target having a recess, in which a conductor is to be provided, formed on its surface is housed in the reaction container; and a supercritical fluid dissolved with a metal compound containing a metal as a raw material for the conductor is supplied into the reaction container. A supply device supplies the supercritical fluid to the inside of the reaction container continuously. A discharge device discharges the fluid, which does not contribute to the process of forming the conductor in the recess, to the outside of the reaction container to adjust the amount of the supercritical fluid in the reaction container, and the metal compound dissolved in the supercritical fluid is introduced into the recess in contact with the surface of the process target. The metal compound in the recess is aggregated. Thereby, a metal is deposited and solidified from the metal compound, to form the conductor in the recess. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for providing a conductor in a recess, and in particular, a conductor forming apparatus and a forming method for providing a conductor using a so-called supercritical fluid inside a hole or groove having a fine aspect ratio and a high aspect ratio. The present invention also relates to a method of manufacturing a semiconductor device for providing fine wirings, plugs, electrodes or the like on a semiconductor substrate using these devices or methods.

  In order to form a fine structure such as an integrated circuit or a microelectronic element, fine wiring, plugs, electrodes, or the like must be formed. For this purpose, a step of filling a conductor such as a metal into a minute recess having a high aspect ratio, such as a wiring formation groove, a plug formation hole, or an electrode formation recess, is substantially essential. At present, in such an embedding process, for example, a method of embedding a metal thin film in a recess using, for example, a vapor deposition method, a plating method, a CVD method, or a PVD method is generally used. On the other hand, in recent years, miniaturization and high integration of various electronic devices including semiconductor devices such as LSI have been remarkably advanced. In the near future, it will inevitably be necessary to form a structure with an ultrafine size of 100 nm or less. However, each of the above-described embedding methods has already approached the limit of embedding properties, and it has become clear that it is extremely difficult to embed an ultrafine concave portion of 100 nm or less without a gap.

In order to overcome such problems, recently, a method of embedding a metal thin film in a recess using a so-called supercritical fluid has been proposed. Such a technique is disclosed in Non-Patent Documents 1 and 2, for example. A supercritical fluid generally refers to a high-density fluid that is indistinguishable from gas (gas phase) and liquid (liquid phase). For example, carbon dioxide (CO ₂ ) becomes a supercritical fluid when the pressure is about 7.4 MPa and the temperature is about 31 ° C. or higher. Supercritical fluids have various characteristics such as solvent ability and nano-level permeability. After dissolving the organometallic complex that is the raw material of the metal thin film in such a supercritical fluid, the metal thin film is deposited by, for example, reacting with a gaseous reaction aid as necessary to precipitate the metal. be able to. As a result, the metal thin film can be filled in the microstructure using the permeability and high density of the supercritical fluid. However, the embedding process using the supercritical fluid is generally performed under high pressure as described above. For this reason, the reaction is completed by filling the raw material of the metal thin film in a state in which the raw material of the metal thin film is dissolved in the supercritical fluid in a sealed container containing a member in which the metal thin film is embedded. Processing performed in such a sealed atmosphere is also referred to as batch processing.
Clean Technology 2004.4 Nippon Kogyo Publishing (2004), 55-58 pages Semiconductor FPD World 2004.8, p.44-47

  However, in the batch processing described above, since the container is sealed except for the inflow path of the raw material, the state in the reaction container during the reaction is likely to become unstable, and the metal thin film to be deposited There is a disadvantage that the controllability of the film thickness and film quality is poor. Specifically, in batch processing, it is difficult to control various film formation parameters that contribute to the film formation reaction, such as the temperature, pressure, raw material concentration in the reaction vessel, or the concentration of various additives that assist the film formation reaction. is there. For this reason, in batch processing, it is difficult to set the film thickness and film quality of the metal thin film formed in the reaction vessel to a desired state. In addition, since the volume of the reaction vessel is unchanged, there is a limit in principle for the continuous supply of the raw material into the reaction vessel and the continuous deposition of the metal thin film on the deposition target member. However, there is a drawback that the upper limit is set by itself. Furthermore, when using a solid raw material, there is also a drawback that it is difficult to control the solubility in a supercritical fluid.

  The present invention has been made in order to solve such problems. The object of the present invention is to provide a conductor using a supercritical fluid inside a hole, groove or recess having a fine aspect ratio and a high aspect ratio. An object of the present invention is to provide a conductor forming apparatus and a forming method capable of improving the controllability when it is provided. At the same time, it is an object of the present invention to provide a method for manufacturing a semiconductor device that can improve controllability when a fine wiring, a plug, an electrode, or the like is provided on a semiconductor substrate using such an apparatus or method.

  In order to solve the above problems, an apparatus for forming a conductor according to one embodiment of the present invention includes an object to be processed in which at least one concave portion provided with a conductor is formed on the surface and accommodates the object. A reaction vessel in which a supercritical fluid in which a metal compound containing a metal as a raw material is dissolved is supplied to the inside and the conductor is provided in the recess; and the supercritical fluid is introduced from the outside of the reaction vessel to the inside. And a discharge device that discharges the supercritical fluid that is not subjected to the process from the inside of the reaction vessel to the outside, and the supply device supplies the supercritical fluid to the reaction vessel. The supercritical fluid that is continuously supplied to the inside and not subjected to the process by the discharge device is continuously discharged to the outside of the reaction vessel, whereby the supercritical fluid in the reaction vessel is discharged. While adjusting the amount of the field fluid, the metal compound dissolved in the supercritical fluid is brought into contact with the surface of the object to be treated and introduced into the concave portion, and the metal compound introduced into the concave portion is introduced into the concave portion. The conductor is provided in the recess by agglomerating in the recess to deposit the metal from the metal compound, and further solidifying the metal deposited in the recess.

  In this conductor forming apparatus, a metal compound containing a metal that is a raw material of a conductor provided in a recess formed on the surface of the object to be processed is dissolved in a supercritical fluid and has high fluidity. In contact with the surface of the object to be processed. Thereby, a metal compound can be smoothly flowed on the surface of a to-be-processed object, and can be preferentially introduce | transduced in the recessed part which consists of a structure lowered | hung to the position lower than the surface of a to-be-processed object. In addition, the metal compound dissolved in the supercritical fluid is introduced into the recess sequentially from the bottom to the top without creating a cavity inside even if the recess is fine and the aspect ratio is high due to its fluidity. Is done. Further, the metal compound dissolved in the supercritical fluid flows preferentially from the surface of the object to be processed into the recess regardless of the material on the inner surface of the recess. Thereby, the metal used as the raw material of the conductor is preferentially precipitated and solidified in the recesses to form the conductor regardless of the material of the base. Therefore, according to the conductor forming apparatus according to one aspect of the present invention, the conductor can be efficiently and selectively placed inside a hole, a recess, a groove, or the like that is fine and has a high aspect ratio, regardless of the material of the base. And can be easily provided.

  Further, in this conductor forming apparatus, when the above-described conductor forming process is performed, a supercritical fluid in which a metal compound is dissolved is continuously supplied to the inside of the reaction vessel by the supply device, and the conductor is supplied by the discharge device. The amount of supercritical fluid inside the reaction vessel is adjusted by continuously discharging the supercritical fluid not subjected to the forming process to the outside of the reaction vessel. As a result, while the conductor formation process is in progress, the inside of the reaction vessel can be filled with the supercritical fluid set to a desired state according to the progress of the process. Can be improved.

  In addition, in order to solve the above-described problem, a method for forming a conductor according to another aspect of the present invention provides a material for the conductor toward a target object in which at least one recess is provided on the surface. The supercritical fluid in which the metal compound containing the metal to be dissolved is continuously supplied, and the supercritical fluid not subjected to the process of providing the conductor in the recess is continuously excluded from the periphery of the object to be processed. By adjusting the amount of the supercritical fluid around the object to be processed, the metal compound dissolved in the supercritical fluid is brought into contact with the surface of the object to be processed, and selectively in the recess. The metal compound introduced into the recess is aggregated in the recess to precipitate the metal from the metal compound, and the metal deposited in the recess is solidified in the recess. Provided Kishirube conductors, it is characterized in.

  In this method of forming a conductor, a metal compound containing a metal that is a raw material of a conductor provided in a recess formed on the surface of the object to be processed is dissolved in a supercritical fluid and has high fluidity. In contact with the surface of the object to be processed. Thereby, a metal compound can be smoothly flowed on the surface of a to-be-processed object, and can be preferentially introduce | transduced in the recessed part which consists of a structure lowered | hung to the position lower than the surface of a to-be-processed object. In addition, the metal compound dissolved in the supercritical fluid is introduced into the recess sequentially from the bottom to the top without creating a cavity inside even if the recess is fine and the aspect ratio is high due to its fluidity. Is done. Further, the metal compound dissolved in the supercritical fluid flows preferentially from the surface of the object to be processed into the recess regardless of the material on the inner surface of the recess. Thereby, the metal used as the raw material of the conductor is preferentially precipitated and solidified in the recesses to form the conductor regardless of the material of the base. Therefore, according to the method of forming a conductor according to another aspect of the present invention, the conductor is efficiently and selectively placed inside a hole, a recess, a groove, or the like that is fine and has a high aspect ratio, regardless of the underlying material. And can be provided easily.

  Further, in this conductor formation method, when the above-described conductor formation process is performed, the supercritical fluid in which the metal compound is dissolved is continuously supplied toward the object to be processed and is not subjected to the conductor formation process. By continuously removing the supercritical fluid from the periphery of the object to be processed, the amount of the supercritical fluid around the object to be processed is adjusted. As a result, while the conductor formation process is in progress, the object to be processed can be wrapped with a supercritical fluid set in a desired state according to the progress of the process, thereby improving the controllability of the conductor formation process. Can be made.

  Furthermore, in order to solve the above-described problem, a method of manufacturing a semiconductor device according to still another aspect of the present invention includes providing a conductor on at least one of a substrate body and an insulating film provided above the substrate body. A process of continuously supplying a supercritical fluid in which a metal compound containing a metal serving as a raw material of the conductor is dissolved toward a semiconductor substrate on which at least one recess is formed, and providing the conductor in the recess. The amount of the supercritical fluid around the semiconductor substrate is adjusted by continuously removing the supercritical fluid that is not provided from the periphery of the semiconductor substrate, and the metal compound dissolved in the supercritical fluid is The metal compound is selectively introduced into the recess by being brought into contact with the surface of the semiconductor substrate, and the metal compound introduced into the recess is aggregated in the recess. Et the metal to deposit, the provision of the conductor in the recess by solidifying the metal deposited in the recess, it is characterized in.

  In this method of manufacturing a semiconductor device, a metal including a metal that is a raw material for a conductor provided in a recess formed in at least one of a substrate body of a semiconductor substrate and an insulating film provided above the substrate body The compound is dissolved in a supercritical fluid and brought into contact with the surface of the semiconductor substrate in a state where the compound is rich in fluidity. As a result, the metal compound can flow smoothly on the surface of the semiconductor substrate, and can be preferentially introduced into the concave portion having a structure lowered to a position lower than the surface of the semiconductor substrate. In addition, the metal compound dissolved in the supercritical fluid is introduced into the recess sequentially from the bottom to the top without creating a cavity inside even if the recess is fine and the aspect ratio is high due to its fluidity. Is done. Further, the metal compound dissolved in the supercritical fluid flows preferentially into the recess from the surface of the semiconductor substrate regardless of the material of the inner surface of the recess. Thereby, the metal used as the raw material of the conductor is preferentially precipitated and solidified in the recesses to form the conductor regardless of the material of the base. Therefore, according to the method for manufacturing a semiconductor device according to still another aspect of the present invention, fine wirings, plugs, electrodes, and the like can be provided efficiently and easily.

  Further, in this method of manufacturing a semiconductor device, when performing the above-described conductor formation process, a supercritical fluid in which a metal compound is dissolved is continuously supplied toward the semiconductor substrate and is not subjected to the conductor formation process. The amount of supercritical fluid around the semiconductor substrate is adjusted by continuously removing the critical fluid from the periphery of the semiconductor substrate. Thereby, while the conductor formation process is in progress, the semiconductor substrate can be wrapped with the supercritical fluid set in a desired state according to the progress of the process, thereby improving the controllability of the conductor formation process. be able to.

  According to the metal body forming apparatus according to one aspect of the present invention, when a conductor is provided using a supercritical fluid inside a hole, groove, or recess having a fine and high aspect ratio, the controllability is improved. Can do.

  In addition, according to the method for forming a metal body according to another aspect of the present invention, when a conductor is provided using a supercritical fluid inside a hole, groove, or recess having a fine and high aspect ratio, the controllability is improved. Can be improved.

  Furthermore, according to the method for manufacturing a semiconductor device according to another aspect of the present invention, it is possible to improve controllability when fine wiring, plugs, electrodes, or the like are provided on a semiconductor substrate.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

(First embodiment)
First, a first embodiment according to the present invention will be described with reference to FIGS. In the present embodiment, a technique for preferentially providing a conductor inside a recess having a fine and high aspect ratio using a so-called supercritical fluid, which is a kind of fluid that cannot be distinguished from gas and liquid, will be described. Hereinafter, it demonstrates concretely and in detail.

  First, a conductor forming apparatus 1 according to this embodiment will be described with reference to FIGS.

  As shown in FIG. 1, the conductor forming apparatus 1 is roughly composed of a reaction vessel 2, a supply device 3, a discharge device 4, and the like.

  As shown in FIG. 2, a target object 6 in which a plurality of fine and high aspect ratio concave portions 5 on which a conductor 33 described later is provided is formed on the surface 6 a is accommodated in the reaction vessel 2. The target object 6 is disposed on a target object support part (not shown) provided inside the pressure-resistant reaction vessel 2 in a posture in which each concave portion 5 faces upward. At the same time, a supercritical fluid 8 in which a metal compound 7 containing a metal 32 as a raw material of the conductor 33 is dissolved is supplied from the supply device 3 into the reaction vessel 2. Thereby, the process of providing the conductor 33 in the recess 5 using the supercritical fluid 8 inside the reaction vessel 2 is performed. In the following description, this process is simply referred to as a conductor formation process.

  The supercritical state is generally realized in an environment at a pressure higher than atmospheric pressure. For this reason, as the reaction vessel 2, a pressure vessel having a structure with improved pressure resistance so as to withstand such high pressure is used. The conductor forming process is generally realized in an environment at a temperature higher than room temperature. For this reason, the reaction vessel 2 is a hot wall type vessel with improved heat resistance and heat insulation so as to withstand such high temperatures. Moreover, what is called a tubular furnace type | mold is used for the reaction container 2 so that the inside may be heated uniformly throughout. In addition, although illustration is abbreviate | omitted, the pressure-resistant reaction container 2 is provided with the observation window for observing the inside.

  Further, as indicated by solid line arrows in FIG. 2, the supercritical fluid 8 supplied from the supply device 3 is supplied from the outside to the inside of the pressure-resistant reaction vessel 2 through the supply port 9. At the same time, the supercritical fluid 8 in the pressure-resistant reaction vessel 2 that is not subjected to the conductor formation process passes through a discharge port 10 provided separately from the supply port 9 as shown by a solid line arrow in FIG. Then, the discharge device 4 discharges the inside of the pressure-resistant reaction vessel 2 to the outside. According to such a configuration, the supply of the metal compound 7 and the supercritical fluid 8 into the pressure-resistant reaction vessel 2 and the discharge of the metal compound 7 and the supercritical fluid 8 from the pressure-resistant reaction vessel 2 are connected to the supply device 3 and It can carry out continuously using the discharge device 4.

  The discharge port 10 is preferably provided on the downstream side of the supply port 9 along the flow of the supercritical fluid 8 introduced into the pressure-resistant reaction vessel 2 through the supply port 9. More preferably, as shown in FIG. 2, the discharge port 10 is provided so as to be aligned with the supply port 9 along the flow of the supercritical fluid 8 introduced into the pressure-resistant reaction vessel 2 through the supply port 9. It should be done. More preferably, as shown in FIG. 2, the object to be processed 6 may be disposed at a position not on a straight line connecting the supply port 9 and the discharge port 10. According to such a configuration, there is no possibility that the flow of the supercritical fluid 8 is blocked by the workpiece 6, and the supercritical fluid 8 can smoothly enter and exit the pressure-resistant reaction vessel 2. Thereby, the atmosphere in the reaction vessel 2 can be quickly and easily set to a uniform state as a whole or set to a stable state. As a result, the controllability can be improved when performing the conductor formation process.

  As shown in FIGS. 1 and 2, a first temperature control device 11 for adjusting the internal temperature of the pressure-resistant reaction vessel 2 to a temperature at which the conductor formation process easily proceeds is provided around the pressure-resistant reaction vessel 2. Is provided. As described above, the conductor forming process is generally realized in an environment at a temperature higher than room temperature. For this reason, for example, a mantle heater unit is used for the first temperature control device 11 as a heating device for heating the inside of the pressure-resistant reaction vessel 2. The mantle heater unit 11 includes two heaters: an upper mantle heater 11a that heats the inside of the pressure-resistant reaction vessel 2 from above, and a lower mantle heater 11b that heats the inside of the pressure-resistant reaction vessel 2 from below. The upper mantle heater 11a and the lower mantle heater 11b operate independently of each other and can individually heat the inside of the pressure-resistant reaction vessel 2 from the upper part or the lower part thereof.

  For example, only the upper mantle heater 11a among the upper and lower mantle heaters 11a and 11b is periodically operated at a predetermined interval. Then, the inside of the pressure | voltage resistant reaction container 2 is heated by biasing periodically with the predetermined space | interval from the upper side. Then, the inside of the pressure-resistant reaction vessel 2 is periodically heated to a higher temperature at a predetermined interval than the lower portion, and temperature unevenness occurs inside the pressure-resistant reaction vessel 2. When the internal temperature of the pressure-resistant reaction vessel 2 becomes periodically non-uniform at a predetermined interval, the temperature and pressure of the atmosphere in the pressure-resistant reaction vessel 2 also become non-uniform periodically at a predetermined interval. Then, convection is periodically generated at a predetermined interval in the atmosphere in the pressure resistant reaction vessel 2, and a density difference is periodically generated at a predetermined interval in the upper and lower portions of the atmosphere in the pressure resistant reaction vessel 2. That is, pulse-shaped density fluctuations occur in the atmosphere in the pressure resistant reactor 2. As a result, pulse-like fluctuations can be generated in the density of the supercritical fluid 8 supplied into the pressure resistant reactor 2.

  When the density of the supercritical fluid 8 fluctuates, the solubility of the metal compound 7 as a solute that dissolves in the supercritical fluid 8 as a solvent increases. Therefore, the concentration of the metal compound 7 in the pressure-resistant reaction vessel 2 is substantially increased without increasing the supply amount of the metal compound 7 from the supply device 3 by periodically operating only the upper mantle heater 5a at a predetermined interval. Can be increased. As a result, the controllability can be improved when performing the conductor formation process. As a result, wasteful consumption of the metal compound 7 can be suppressed to save raw materials, energy and cost, and an environment-friendly process can be realized. Of course, such a phenomenon can be realized by intermittently operating not only the upper mantle heater 11a but also the lower mantle heater 11b. Alternatively, the same phenomenon can be realized by alternately and intermittently operating the upper and lower mantle heaters 11a and 11b. That is, by operating each of the upper and lower mantle heaters 11a and 11b individually and intermittently, the atmosphere in the pressure resistant reaction vessel 2 is partially non-uniform periodically at a predetermined interval, and the pressure resistant reaction is performed. Pulsed density fluctuations can be generated in the atmosphere in the container 2.

  On the other hand, when the upper and lower mantle heaters 11a and 11b are operated together, the atmosphere in the pressure-resistant reaction vessel 2 is heated uniformly from the upper and lower sides, so that heating unevenness hardly occurs. That is, when the upper and lower mantle heaters 11a and 11b are operated together, the atmosphere in the pressure-resistant reaction vessel 2 is heated evenly as a whole, so that there is almost no pulse fluctuation in the density. Further, by operating both the upper and lower mantle heaters 11a and 11b together, the temperature and pressure of the atmosphere in the pressure resistant reactor 2 can be stabilized and held at a predetermined value as a whole.

  As shown in FIG. 1, the supply device 3 includes a supercritical fluid supply device 12, a raw material supply device 13, a reaction accelerator supply device 14, and the like. The supercritical fluid supply device 12, the raw material supply device 13, and the reaction accelerator supply device 14 can operate independently of each other.

The supercritical fluid supply device 12 includes a supercritical fluid storage device 15, a liquefaction device 16, and a supercritical fluid delivery device 17. The supercritical fluid supply device 12 is provided at the most upstream part in the flow (flow path) of the supercritical fluid 8 of the conductor forming device 1 from the supply device 3 through the pressure-resistant reaction vessel 2 to the discharge device 4. Yes. The supercritical fluid supply device 12 supplies the raw material of the supercritical fluid 8 toward the pressure resistant reactor 2. Here, carbon dioxide (CO ₂ ) is used as a raw material for the supercritical fluid 8. Carbon dioxide is a kind of fluid that is indistinguishable from gas phase (gas) and liquid phase (liquid) and has both properties of gas phase and liquid phase in an atmosphere of about 31 ° C. and about 7.4 MPa. It becomes the super critical fluid (Super Critical Fluid) 8 which is. The supercritical fluid 8 made of carbon dioxide generally has the following characteristics. First, it has a high density close to that of a liquid and a strong dissolving power, and acts as a solvent. Second, it has high diffusivity and low viscosity close to the state of gas. Third, the surface tension is substantially zero. Fourth, the critical pressure and critical temperature when changing from a gas or liquid state to a supercritical state are low, and the phase can be easily changed to a supercritical fluid state. Fifth, it has solvent ability. Sixth, it has nano-level permeability. Seventh, carbon dioxide is stable, inexpensive and low-cost, highly recyclable, and has less impact on the environment than fluorine.

Carbon dioxide is stored in a substantially liquid state in a siphon cylinder 15 as a supercritical fluid storage device. The carbon dioxide taken out from the cylinder 15 is first cooled by a cooling device 16 as a liquefying device and is almost completely liquefied. Thereafter, the liquefied carbon dioxide is pressurized by a supercritical fluid delivery pump 17 as a supercritical fluid delivery device and sent toward the pressure resistant reaction vessel 2. Here, a high pressure pump is used as the supercritical fluid delivery pump 17 to increase the pressure of liquid carbon dioxide to, for example, about 10 MPa. According to the supercritical fluid supply device 12 having such a configuration, the supercritical fluid 8 made of carbon dioxide can be continuously supplied toward the pressure resistant reactor 2. In the following description, carbon dioxide in a supercritical state is referred to as a supercritical CO ₂ fluid (CO ₂ (SC)) 8, and is referred to as liquid carbon dioxide (CO ₂ (liq)) or gaseous dioxide. Differentiated from carbon (CO ₂ (gas)).

As shown in FIG. 1, the raw material supply device 13 includes a raw material storage device 18, a raw material delivery device 19, and a raw material delivery valve 20. The raw material supply device 13 is connected to the flow path of the supercritical CO ₂ fluid 8 of the conductor forming device 1 upstream from the pressure-resistant reaction vessel 2 and downstream from the supercritical fluid supply device 12. The raw material supply device 13 supplies the metal compound 7 containing the metal 32 that is the raw material of the conductor 33 by dissolving it in the supercritical CO ₂ fluid 8. As will be described later, in this embodiment, the conductor 33 is formed using copper (Cu). Therefore, here, the metal compound 7 containing copper is used as the metal compound 7. Specifically, diisobutyryl methanate copper (Cu (C ₇ H ₁₅ O ₂ ) ₂ ; Cu (divm) ₂ ), which is a kind of solid organometallic complex (precursor), is used. The diisobutyryl methanate copper 7 is stored in a precursor reservoir 18 as a raw material storage device. More specifically, as shown in FIG. 3, diisobutyryl methanate copper 7 is dissolved as a solute in auxiliary solvent 21 that facilitates dissolving diisobutyryl methanate copper 7 in supercritical CO ₂ fluid 8. It is stored in the precursor reservoir 18 in such a state. Here, acetone (CH ₃ COCH ₃ ), which is a kind of organic solvent, is used as the auxiliary solvent 21.

  Here, the reason for selecting acetone as the auxiliary solvent 21 will be described with reference to FIGS. 4 to 6 are graphs showing the results of experiments conducted by the present inventors. First, FIG. 4 is a graph showing the results of measuring the amount of diisobutyryl methanate copper 7 dissolved in 1 ml of various solvents. According to the graph shown in FIG. 4, it can be seen that the amount of diisobutyryl methanate copper 7 dissolved is increased by cyclohexane jumping out. Next, acetone and hexane are high. Next, FIG. 5 is a graph showing the film thickness of the Cu film for each of various solvents when the Cu film is formed by the batch processing described in the background art. According to the graph shown in FIG. 5, it is understood that the thickest Cu film can be obtained when acetone is used as an auxiliary solvent. FIG. 6 is a graph showing the (1 1 1) / (2 0 0) relative intensity ratio of the Cu film for each of the various solvents when the Cu film is formed by batch processing. According to the graph shown in FIG. 6, it can be seen that a Cu film having the highest (1 1 1) / (2 0 0) relative intensity ratio can be obtained when acetone is used as an auxiliary solvent. In contrast, when cyclohexane is used as the auxiliary solvent, it can be seen that the (1 1 1) / (2 0 0) relative intensity ratio of the Cu film is the lowest. It is generally known that the higher the (1 1 1) / (2 0 0) relative intensity ratio, the higher the reliability as a metal thin film used in an electronic device such as a semiconductor device.

The inventors comprehensively judged the results shown in the graphs of FIGS. 4 to 6 and selected acetone as the auxiliary solvent 21 suitable for the diisobutyryl methanate copper 7. In addition, although specific and detailed description accompanied with illustration is abbreviate | omitted, according to the result of the additional experiment which the present inventors performed further, when acetone is used as the auxiliary solvent 21, it is other than acetone, such as hexane and cyclohexane. It was also found that the film formation rate can be increased and the crystallinity can be improved as compared with the case where a substance is used as the auxiliary solvent 21. Acetone is less expensive than hexane, cyclohexane, or the like. Therefore, by using acetone as the auxiliary solvent 21, the throughput speed of the conductor forming process and the quality and reliability of the conductor 33 formed by the conductor forming process can be improved and the conductor forming process is applied. Cost can be reduced or suppressed. However, according to the results of additional experiments conducted by the present inventors, when 10% or more of acetone is mixed in the supercritical CO ₂ fluid 8 per unit amount, the supercritical CO ₂ fluid 8 is composed of CO ₂ and acetone. It was also confirmed that it separated into two phases and was not a homogeneous phase. Therefore, the present inventors have determined that the ratio of acetone mixed in the supercritical CO ₂ fluid 8 per unit amount is less than 10%.

The diisobutyryl methanate copper 7 stored in the precursor reservoir 18 is first dissolved in acetone 21 by a raw material delivery pump 19 as a raw material delivery device as shown by a solid line arrow in FIG. In the state, it is taken out from the precursor reservoir 18. Next, as shown in FIG. 1, by opening the raw material delivery valve 20, the diisobutyryl methanate copper 7 and acetone 21 taken out from the precursor reservoir 18 are sent from the supercritical fluid supply device 12. Supplied into the CO ₂ fluid 8. That is, the diisobutyryl methanate copper 7 is further dissolved in the supercritical CO ₂ fluid 8 while being dissolved in the acetone 21. Thereby, the diisobutyryl methanate copper 7 containing the copper 32 used as the raw material of the conductor 33 is supplied with the supercritical CO ₂ fluid 8 toward the inside of the pressure resistant reactor 2. According to the raw material supply device 13 having such a configuration, the diisobutyryl methanate copper 7 dissolved in the acetone 21 can be continuously supplied into the supercritical CO ₂ fluid 8. As a result, according to the raw material supply device 13, diisobutyryl methanate copper 7 dissolved in acetone 21 in the flow path (line) of the supercritical CO ₂ fluid 8 of the conductor forming device 1 including the pressure resistant reactor 2. Can be supplied continuously. Note that the raw material supply device 13 including the precursor reservoir 18, the raw material delivery pump 19, and the raw material delivery valve 20 is also referred to as a raw material addition unit.

Further, the supply device 3 supplies diisobutyryl into the supercritical CO ₂ fluid 8 by the raw material supply device 13 while supplying the supercritical CO ₂ fluid 8 into the pressure-resistant reaction vessel 2 by the supercritical fluid supply device 12. The supply of the methanate copper 7 can be stopped. Accordingly, supplying the supercritical CO ₂ fluid 8 diisobutyryl methanate copper 7 instead of the supercritical CO ₂ fluid 8 diisobutyryl methanate copper 7 is dissolved is not dissolved in the pressure-resistant reaction container 2 Can do. For this purpose, the material supply device 13 does not need to stop both the material delivery pump 19 and the material delivery valve 20. It is sufficient for the material supply device 13 to stop either the material delivery pump 19 or the material delivery valve 20. For example, the supercritical CO ₂ fluid 8 not containing diisobutyryl methanate copper 7 is supplied into the pressure-resistant reaction vessel 2 by stopping the operation of the raw material delivery pump 19 or completely closing the raw material delivery valve 20. be able to. Eventually, the amount and concentration of diisobutyryl methanate copper 7 or copper 32 in the pressure-resistant reaction vessel 2 are adjusted by adjusting the output and operating rate of the raw material delivery pump 19 or by adjusting the opening of the raw material delivery valve 20. Can be appropriately set to an appropriate state.

As shown in FIG. 1, the reaction accelerator supply device 14 includes a reaction accelerator storage device 22 and a mixing device (mixing unit) 23. The reaction accelerator supply device 14 is connected to the flow path of the supercritical CO ₂ fluid 8 of the conductor forming device 1 upstream from the raw material supply device 13 and downstream from the supercritical fluid supply device 12. Yes. Although not shown in FIG. 1, the reaction accelerator supply device 14 supplies a reaction accelerator 31 that promotes precipitation of the metal 32 from the metal compound 7 into the supercritical fluid 8. In this embodiment, the reaction accelerator supply device 14 supplies a reaction accelerator 31 that promotes the precipitation of copper 32 from the diisobutyryl methanate copper 7 into the supercritical CO ₂ fluid 8. Here, hydrogen (H ₂ ) 31 is used as such a reaction accelerator. The hydrogen 31 has an action of reducing and precipitating the copper 32 contained in the diisobutyryl methanate copper 7 dissolved in the supercritical CO ₂ fluid 8.

The hydrogen 31 is also expected to have an action (entrainer effect) for increasing the saturation solubility of the diisobutyryl methanate copper 7 in the supercritical CO ₂ fluid 8. If hydrogen 31 has the entrainer effect, by incorporating hydrogen 31 in the supercritical CO ₂ fluid 8, as compared with the case where in the supercritical CO ₂ fluid 8 not to mix the hydrogen 31, Jiisobuchiri Rumethanate copper 7 can be excessively dissolved in the supercritical CO ₂ fluid 8. The copper 32 contained in the diisobutyryl methanate copper 7 excessively dissolved in the supercritical CO ₂ fluid 8 is likely to precipitate at least during the course of the conductor formation process. Therefore, by mixing the hydrogen 31 into the supercritical CO ₂ fluid 8, it can be expected that the time required for the step of filling the recesses 5 with the copper 32 can be shortened. That is, the effect of increasing the throughput speed of the conductor forming process can be expected.

As shown in FIG. 1, the hydrogen 31 is stored in a siphon cylinder 22 as a reaction accelerator storage device. The hydrogen 31 taken out from the cylinder 22 is a mixing unit provided at the connection between the reaction accelerator supply device 14 and the flow path of the supercritical CO ₂ fluid 8 from the supercritical fluid supply device 12 toward the pressure resistant reactor 2. 23 is mixed into the supercritical CO ₂ fluid 8. According to the reaction accelerator supply device 14 having such a configuration, the hydrogen 31 can be continuously injected into the supercritical CO ₂ fluid 8. As a result, according to the reaction accelerator supply device 14, the hydrogen 31 can be continuously injected into the flow path (line) of the supercritical CO ₂ fluid 8 of the conductor forming device 1 including the pressure resistant reactor 2. it can.

Further, as described above, the reaction accelerator supply device 14 is connected to the flow path of the supercritical CO ₂ fluid 8 on the upstream side of the raw material supply device 13. Therefore, hydrogen 31 prior to diisobutyryl methanate copper 7 dissolved in acetone 21 is dissolved in the supercritical CO ₂ fluid 8, it is incorporated in the supercritical CO ₂ fluid 8. The amount and concentration of hydrogen 31 in the supercritical CO ₂ fluid 8, suitably by adjusting the mixing ratio of hydrogen 31 for the supercritical CO ₂ fluid 8 in the mixing unit 23 can be set to a proper state. As a result, by adjusting the amount and concentration of hydrogen 31 in the supercritical CO ₂ fluid 8 with the mixing unit 23, the solubility of the diisobutyryl methanate copper 7 in the supercritical CO ₂ fluid 8 is appropriately adjusted to an appropriate state. Can be set. For example, by completely closing the mixing unit 23, the injection of the hydrogen 31 into the supercritical CO ₂ fluid 8 is stopped. Thereby, the solubility of the diisobutyryl methanate copper 7 in the supercritical CO ₂ fluid 8 can be reduced. At the same time, the supercritical CO ₂ fluid 8 not containing hydrogen 31 can be supplied into the pressure resistant reactor 2.

Further, as shown in FIG. 1, in the flow path of the supercritical CO ₂ fluid 8 of the conductor forming device 1, a supercritical fluid delivery valve is located upstream of the raw material supply device 13 and downstream of the mixing unit 23. 24 is provided. By opening the supercritical fluid delivery valve 24 can be supplied toward the supercritical CO ₂ fluid 8 supercritical CO ₂ fluid 8 or hydrogen 31 is injected into the pressure-resistant reaction container 2. Further, by adjusting the opening degree of the supercritical fluid delivery valve 24, the supply amount of the supercritical CO ₂ fluid 8 into which the supercritical CO ₂ fluid 8 or hydrogen 31 has been injected into the pressure-resistant reaction vessel 2 is appropriately set appropriately. Can be set to state. As a result, as described above, not only by adjusting the raw material delivery pump 19 and the raw material delivery valve 20 included in the raw material supply device 13 but also by adjusting the opening degree of the supercritical fluid delivery valve 24, The concentration of tyrylmethanate copper 7 or copper 32 can be appropriately set to an appropriate state.

As shown in FIG. 1, the discharge device 4 includes a pressure gauge 25, a pressure adjustment valve 26, a pressure adjustment device 27, and a separator 28. The discharge device 4 is provided in the most downstream portion on the downstream side of the pressure resistant reactor 2 in the flow path of the supercritical CO ₂ fluid 8 of the conductor forming device 1. The discharge device 4 discharges the supercritical CO ₂ fluid 8 and the like not subjected to the conductor formation process from the inside of the pressure resistant reactor 2 to the outside. Specifically, the back pressure valve 26 as a pressure control valve is opened and a back pressure regulator (Back Pressure Regulator: BPR) 27 as a pressure regulator is operated. Thereby, the pressure of the flow path downstream from the pressure resistant reaction container 2 in the flow path of the supercritical CO ₂ fluid 8 of the conductor forming apparatus 1 is set lower than the internal pressure of the pressure resistant reaction container 2. As a result, the supercritical CO ₂ fluid 8 that is not subjected to the conductor forming process in the pressure resistant reactor 2 is discharged from the inside of the pressure resistant reactor 2 to the outside. At this time, the pressure in the flow path downstream from the pressure-resistant reaction vessel 2 is set so that it can be automatically maintained in an appropriate state by the back pressure valve 26 and the back pressure adjusting device 27 while being monitored by a pressure gauge (pressure sensor) 25. It is preferable.

In addition, the back pressure valve 26 and the back pressure adjusting device 27 include the supercritical fluid delivery pump 17, the material delivery pump 19, the material delivery valve 20, and the supercritical fluid delivery valve 24 described above, as well as the supercritical CO of the conductor forming device 1. _It has the role of controlling the pressure of the entire flow path of the _two fluids 8 to an appropriate value at any time. In particular, the back pressure valve 26 and the back pressure adjusting device 27, together with the supercritical fluid delivery pump 17, the material delivery pump 19, the material delivery valve 20, and the supercritical fluid delivery valve 24, are in progress during the conductor formation process. The pressure inside the pressure-resistant reaction container 2 has a role of adjusting and holding the pressure appropriately in accordance with the progress of the conductor formation process. Further, the back pressure valve 26, the back pressure adjusting device 27, the supercritical fluid delivery pump 17, the raw material delivery pump 19, the raw material delivery valve 20, and the supercritical fluid delivery valve 24 are respectively adjusted, and the conductor formation process proceeds. Needless to say, the pressure in the pressure-resistant reaction vessel 2 can be kept stable at a predetermined value during the period. By these, a conductor formation process can be advanced appropriately.

Further, the back pressure valve 26 and the back pressure adjustment device 27 can cause pulse-like density fluctuations in the atmosphere in the pressure resistant reactor 2 as in the case of the upper and lower mantle heaters 11a and 11b. For example, the pressure sensor 25 monitors the pressure in the downstream flow path from the pressure-resistant reaction container 2 so that the pressure in the pressure-resistant reaction container 2 is in the range of about ± 10% and periodically rises and falls at a predetermined interval. At the same time, the back pressure valve 26 and the back pressure adjusting device 27 are operated. Then, the pressure of the atmosphere inside the pressure-resistant reaction vessel 2 is also in the range of about ± 10% and periodically rises and falls at a predetermined interval, so that the density of the atmosphere in the pressure-resistant reaction vessel 2 is about ± 10%. And periodically non-uniform at predetermined intervals. That is, a pulse-like fluctuation can be generated in the density of the atmosphere in the pressure resistant reactor 2. Specifically, pulse-like fluctuations can be generated in the density of the supercritical CO ₂ fluid 8 containing diisobutyryl methanate copper 7, acetone 21, and hydrogen 31 supplied into the pressure resistant reactor 2.

  As a result, the concentration of the diisobutyryl methanate copper 7 in the pressure resistant reactor 2 can be substantially increased without increasing the supply amount of the metal compound 7 from the supply device 3, or the controllability of the conductor forming process can be increased. It can be improved. At the same time, wasteful consumption of the diisobutyryl methanate copper 7 can be suppressed to save raw materials, energy and costs, and to realize an environment-friendly process. It should be noted that not only the back pressure valve 26 and the back pressure adjusting device 27 but also the supercritical fluid delivery pump 17 and the supercritical fluid delivery valve 24 are operated, so that the atmosphere in the pressure resistant reaction vessel 2 has a pulse-like density fluctuation. Of course, it can be generated.

The supercritical CO ₂ fluid 8 and the like discharged from the pressure-resistant reaction vessel 2 are sent to a separator (separator) 28 provided downstream of the back pressure adjusting device 27. In the separator 28, unreacted diisobutyryl methanate copper 7 that has not contributed to the conductor forming process contained in the supercritical CO ₂ fluid 8 is recovered. By measuring the concentration of the diisobutyryl methanate copper 7 recovered by the separator 28, the usage rate of the raw material in the conductor forming process using the conductor forming apparatus 1 can be obtained as described later.

Further, as shown in FIG. 1, in the flow path of the supercritical CO ₂ fluid 8 of the conductor forming device 1, it is dissolved in the supercritical CO ₂ fluid 8 between the supply device 3 and the pressure-resistant reaction vessel 2. A concentration detector 29 for detecting the concentration of the diisobutyryl methanate copper 7 is further provided. More specifically, a concentration detection apparatus for optically detecting the concentration of diisobutyryl methanate copper 7 in the supercritical CO ₂ fluid 8 before being subjected to the conductor formation process in the pressure resistant reactor 2. An absorbance analyzer (VIS) 29 is provided between the raw material delivery valve 20 and the supercritical fluid delivery valve 24 and the pressure-resistant reaction vessel 2. The absorbance analyzer 29 can in-line analyze the concentration of diisobutyryl methanate copper 7 in the supercritical CO ₂ fluid 8 prior to being used in the conductor formation process. The concentration of diisobutyryl methanate copper 7 in the supercritical CO ₂ fluid 8 measured by the absorbance analyzer 29 and the diisobutyryl methanate copper in the supercritical CO ₂ fluid 8 measured by the separator 28 described above. By determining the difference from the concentration of 7, the usage rate of the raw material in the conductor forming process using the conductor forming apparatus 1 can be determined.

Further, as shown in FIG. 1, the flow path of the supercritical CO ₂ fluid 8 from the connection portion between the supercritical fluid supply device 12 and the reaction accelerator supply device 14 to the pressure resistant reactor 2 is a second temperature control device. 30 is provided inside. The second temperature adjusting device 30 is installed to adjust the temperature of carbon dioxide, which is a raw material of the supercritical CO ₂ fluid 8, to a temperature that can maintain the supercritical state. As described above, carbon dioxide becomes supercritical at about 31 ° C. Therefore, here, the thermostat 30 that can stably hold the temperature of carbon dioxide at a predetermined temperature is used as the second temperature control device. Specifically, the temperature of carbon dioxide flowing inside the thermostatic chamber 30 is maintained at about 40 ° C. As shown in FIG. 1, a mixing unit 23, a supercritical fluid delivery valve 24, a raw material delivery valve 20, an absorbance analysis among the flow paths of the supercritical CO ₂ fluid 8 of the conductor forming apparatus 1 are disposed inside the thermostatic chamber 30. The device 29 and the pressure resistant reactor 2 are accommodated.

  Next, a method for forming a conductor according to this embodiment will be described with reference to FIGS. 2, 3, 7A to 7D, and FIG. Specifically, the conductor forming method of the present embodiment is the interior of a plurality of fine and high aspect ratio recesses 5 formed on the surface layer portion of the object 6 using the conductor forming apparatus 1 described above. In this method, the conductor 33 is preferentially provided.

First, as shown in FIG. 2, a silicon wafer 6 as an object to be processed is placed inside the pressure resistant reactor 2. Subsequently, the cooling device 16, the supercritical fluid delivery pump 17, the mixing unit 23, the supercritical fluid delivery valve 24, the raw material delivery pump 19, and the raw material delivery valve 20 of the supply device 3 provided in the conductor forming apparatus 1 are operated. Thereby, the supercritical CO ₂ fluid 8 and hydrogen 31 are supplied toward the inside of the pressure resistant reactor 11 in which the silicon wafer 6 is accommodated. At the same time, as shown in FIG. 3, diisobutyryl methanate copper 7 dissolved in acetone 21 is dissolved in supercritical CO ₂ fluid 8 mixed with hydrogen 31 and supplied toward the inside of the pressure resistant reactor 11. To do. Subsequently, the pressure adjusting valve 26 and the pressure adjusting device 27 of the discharge device 4 included in the conductor forming device 1 are operated, and the upper and lower mantle heaters 11a and 11b and the thermostat 30 are operated. Thereby, the pressure and temperature in the pressure | voltage resistant reaction container 2 are set and maintained to the value which a conductor formation process can progress appropriately.

As shown in FIG. 7 (a), at least part of the diisobutyryl methanate copper 7a in the liquid phase is further converted into molecular diisobutyryl methanate copper 7b in the supercritical CO ₂ fluid 8. It becomes easier to dissolve. Further, as described above, in the present embodiment, hydrogen 31 is contained in the supercritical CO ₂ fluid 8 so that the copper 32 is easily deposited from the diisobutyryl methanate copper 7 when the conductor formation process is in progress. Is added to dissolve the diisobutyrylmethanate copper 7 in the supercritical CO ₂ fluid 8 until it becomes supersaturated. According to this method, the diisobutyrylmethanate copper 7 (into the supercritical CO ₂ fluid 8 is introduced into the supercritical CO ₂ fluid 8 by introducing the hydrogen 31 without introducing excess diisobutyrylmethanate copper 7 into the pressure resistant reactor 2. The solubility of 7a, 7b) can be increased.

The supercritical CO ₂ fluid 8 is a very stable object from the viewpoint of chemical reaction. Therefore, in the state where the diisobutyryl methanate copper 7b is supersaturated with respect to the supercritical CO ₂ fluid 8, the molecular diisobutyryl methanate copper 7b and the supercritical CO ₂ fluid 8 are in phase with each other. It coexists in the atmosphere in the pressure resistant reactor 2 in the separated two-phase separated state. That is, there is almost no possibility that the molecular diisobutyryl methanate copper 7b and the supercritical CO ₂ fluid 8 undergo a chemical reaction with each other and deteriorate. In addition, since the supercritical CO ₂ fluid 8 has a high diffusibility equivalent to that of gas, the molecular diisobutyryl methanate copper 7b is dissolved almost uniformly in the supercritical CO ₂ fluid 8 evenly. ing.

First, as shown in FIG. 7A, a silicon wafer 6 as a foreign object in an atmosphere in which molecular diisobutyryl methanate copper 7b, supercritical CO ₂ fluid 8, acetone 21, and hydrogen 31 coexist. Is present, the molecular diisobutyryl methanate copper 7b is attracted toward the silicon wafer 6 by affinity. The molecular diisobutyryl methanate copper 7b contacts the surface 6a of the silicon wafer 6 and is adsorbed or adhered. However, since the molecular diisobutyryl methanate copper 7b is dissolved in the supercritical CO ₂ fluid 8 whose surface tension is almost zero, the fluidity of the diisobutyryl methanate copper 7b is in a high density state with very high fluidity. Yes. For this reason, the molecular diisobutyryl methanate copper 7b adsorbed or adhered to the surface 6a of the silicon wafer 6 flows smoothly along the surface 6a of the silicon wafer 6 as shown in FIG. It is introduced in a self-aligning manner and selectively into each of the recesses 5 having a structure dug down from the surface 6a of the silicon wafer 6 and formed at a low position. That is, the molecular diisobutyryl methanate copper 7 b adsorbed or adhered to the surface 6 a of the silicon wafer 6 is preferentially introduced into each recess 15.

Next, as shown in FIG. 7 (b), when molecular diisobutyryl methanate copper 7b enters each recess 5, the density of the atmosphere in the pressure resistant reactor 2 is increased in the vicinity of the surface 6a of the silicon wafer 6. Fluctuation occurs. As a result, the density of the supercritical CO ₂ fluid 8 fluctuates. Specifically, the atmosphere in the pressure resistant reactor 2 and the density of the supercritical CO ₂ fluid 8 are high in the upper part of the pressure resistant reactor 2 and low in the lower part. Then, the plurality of molecular diisobutyryl methanate coppers 7b dissolved in a supersaturated state in the supercritical CO ₂ fluid 8 are attracted to each other and aggregate by capillary action. As a result, liquid diisobutyryl methanate copper 7 a is deposited in each recess 5.

Next, as shown in FIG. 7 (c), the liquid diisobutyryl methanate copper 7 a deposited in each recess 5 is formed so that the inside of each recess 5 is located above the bottom from the bottom in the same manner as a general liquid. We will meet gradually toward the future. As described above, since the supercritical CO ₂ fluid 8 has a high density, the molecular diisobutyryl methanate copper 7 b dissolved in the supercritical CO ₂ fluid 8 is disposed inside each recess 5. It is possible to enter with almost no gap. Therefore, the inside of each recess 5 is filled with liquid diisobutyryl methanate copper 7a sequentially without gaps from the bottom to the top.

The liquid diisobutyryl methanate copper 7a deposited in each recess 5 reacts with the hydrogen 31 and is reduced. Thereby, the copper 32 which is the main component of the conductor 33 is decomposed from the liquid diisobutyryl methanate copper 7a and deposited in each recess 5. Therefore, in this conductor formation process, the inside of each recess 5 is filled with the liquid diisobutyryl methanate copper 7a without gaps sequentially from the bottom to the top, In this case, the copper 32 is sequentially deposited without any gap from the bottom to the top. In such a precipitation reaction of copper 32, hydrogen 31 functions as a reducing agent for diisobutyryl methanate copper 7a. The copper 32 deposited in each recess 5 is sequentially deposited from the bottom to the top in each recess 5 by capillary aggregation. Copper 32 is deposited in each recess 5 until the inside of each recess 5 is filled with copper 32 with almost no gap. Note that, when hydrogen 31 is consumed in such a reduction precipitation reaction of copper 32 with hydrogen 31, the solubility of diisobutyryl methanate copper 7b in the supercritical CO ₂ fluid 8 decreases, so that the aggregation of copper 32 occurs. Progress more and more.

In this embodiment, the supercritical CO ₂ fluid 8 and the diisobutyryl methanate copper 7 and the like are continuously supplied into the pressure-resistant reaction vessel 2 by the supply device 3 while such a conductor formation process is in progress. At the same time, the supercritical CO ₂ fluid 8 and the diisobutyryl methanate copper 7 and the like not subjected to the conductor forming process are continuously discharged out of the pressure resistant reactor 2 by the discharge device 4. As a result, the amount of supercritical CO ₂ fluid 8 and diisobutyryl methanate copper 7 in the pressure resistant reactor 2 is adjusted to appropriate values as needed according to the progress of the conductor formation process. The process can proceed in a proper state. For example, while the conductor formation process is in progress, the supply amount of supercritical CO ₂ fluid 8 and diisobutyryl methanate copper 7 and the like inside the pressure-resistant reaction vessel 2 by the supply device 3 and the conductor by the discharge device 4 The amount of supercritical CO ₂ fluid 8 and diisobutyryl methanate copper 7 that are not subjected to the formation process is continuously adjusted to the outside of the pressure resistant reactor 2. As a result, the pressure in the pressure-resistant reaction vessel 2, the amount of supercritical CO ₂ fluid 8, the amount and concentration of diisobutyryl methanate copper 7 are set to predetermined values so that the conductor formation process proceeds in an appropriate state. Can stabilize.

Further, by adjusting the supply amount of hydrogen 31 into the supercritical CO ₂ fluid 8 by the reaction accelerator supply device 14 and the discharge amount of the supercritical CO ₂ fluid 8 from the pressure-resistant reaction vessel 2 by the discharge device 4, The concentration of hydrogen 31 in the pressure resistant reactor 2 can be stabilized at a predetermined value. Of course, this also allows the conductor formation process to proceed in an appropriate state. Furthermore, the temperature in the supercritical CO ₂ fluid 8 and the pressure-resistant reaction vessel 2 flowing through the flow path of the conductive system device 1 is adjusted to an appropriate value at any time by the upper and lower mantle heaters 11a and 11b and the thermostat 30. As a matter of course, the conductor forming process can be performed in an appropriate state.

Then, as shown in FIG. 7D, the Cu thin film 33 is deposited until the thin film (Cu thin film) 33 made of copper 32 overflows on the surface 6a of the silicon wafer 6 from the inside of each recess 5, and then supplied. The cooling device 16, supercritical fluid delivery pump 17, mixing unit 23, supercritical fluid delivery valve 24, raw material delivery pump 19, and raw material delivery valve 20 of the apparatus 3 are stopped, and supercritical CO into the pressure-resistant reaction vessel 2 is stopped. _2. Supply of fluid 8, hydrogen 31, diisobutyryl methanate copper 7, and acetone 21 is stopped. Subsequently, the supercritical CO ₂ fluid 8, hydrogen 31, diisobutyryl methanate copper 7, and acetone 21 that have not contributed to the conductor formation process remaining in the pressure-resistant reaction vessel 2 are pressure-reacted by the discharge device 4. After confirming that the discharge from the container 2 has been completed, the pressure adjustment valve 26 and the pressure adjustment device 27 of the discharge device 4 are stopped. Further, the upper and lower mantle heaters 11a and 11b and the thermostat 30 are stopped. Thereby, the conductor formation process of this embodiment is complete | finished. 7A to 7D are enlarged cross-sectional views showing the vicinity of each recess 5 formed in the silicon wafer 6 in order to easily understand the conductor formation process in the pressure resistant reactor 2. FIG.

  As a result, as shown in FIG. 8, a thin film 33 made of a simple substance of Cu as a conductor is formed inside and near the openings of the plurality of fine and high aspect ratio concave portions 5 formed in the surface layer portion of the silicon wafer 6. Is preferentially provided. And the inside of each recessed part 5 is filled with the Cu thin film 33 without a substantially gap, without forming a depletion (void).

As shown in FIG. 1, in the above-described conductor forming apparatus 1, the absorbance analyzer 29 is directly connected to the pressure resistant reaction container 2, but the present invention is not limited to this. For example, as shown in FIG. 9, supercritical CO ₂ from the fluid 8 diisobutyryl methanate copper 7 while suppressing the reaction of precipitation diisobutyryl methanate copper 7 resistant reaction supercritical CO ₂ fluid 8 was dissolved You may connect the reaction suppression part 34 introduce | transduced in the inside of the container 2 to the upstream of the pressure | voltage resistant reaction container 2 immediately. As such a reaction suppression unit 34, for example, as shown in FIG. 9, a supercritical CO ₂ fluid 8 in which diisobutyryl methanate copper 7 is dissolved can be introduced into the pressure resistant reactor 2 while stirring. A tubular path formed in a spiral shape may be used. At the same time, on the outside of the reaction suppression unit 34, the internal temperature of the reaction suppression unit 34 is adjusted to a temperature at which the precipitation reaction of the diisobutyryl methanate copper 7 from the supercritical CO ₂ fluid 8 can be suppressed. It is more preferable to provide the third temperature adjusting device 35. Similarly to the first temperature control device 11 provided in the pressure-resistant reaction vessel 2 described above, the third temperature control device 35 is also of a vertically divided type so that the reaction suppression unit 34 can be heated uniformly from its surroundings. Mantle heaters 35a and 35b may be used.

According to experiments conducted by the present inventors, by heating the temperature of the supercritical CO ₂ fluid 8 etc. flowing in the reaction suppression unit 34 to a temperature lower than the internal temperature of the pressure resistant reactor 2, diisobutyryl meta It was found that the supercritical CO ₂ fluid 8 in which the nat copper 7 was uniformly dissolved could be introduced into the pressure resistant reactor 2. For example, it is assumed that the internal temperature of the pressure resistant reactor 2 when the conductor forming process is performed is set to about 280 ° C. In this case, the temperature of the supercritical CO ₂ fluid 8 and the like flowing through the reaction suppression unit 34 is set to about 200 ° C. or less. More preferably, the temperature of the supercritical CO ₂ fluid 8 and the like flowing in the reaction suppression unit 34 is set to about 150 ° C. Thus, the supercritical CO ₂ fluid 8 in which the diisobutyryl methanate copper 7 is uniformly dissolved is suppressed inside the pressure-resistant reaction vessel 2 while suppressing the reaction of the diisobutyryl methanate copper 7 being precipitated from the supercritical CO ₂ fluid 8. It was found that can be introduced.

  Thus, by providing the reaction suppression unit 34 and the upper and lower mantle heaters 35a and 35b immediately upstream of the pressure resistant reaction vessel 2, the amount of diisobutyryl methanate copper 7 introduced into the pressure resistant reaction vessel 2 can be increased. The concentration can be controlled with higher accuracy. As a result, the conductor forming process can be controlled with higher accuracy, and the fine and high aspect ratio recesses 5 can be filled with the Cu thin film 33 more efficiently.

As described above, in the first embodiment, the same solubility as liquid, high diffusibility equivalent to gas, surface tension close to zero, high density, nano-level permeability, and chemically In a stable supercritical CO ₂ fluid 8, diisobutyryl methanate copper 7 as a raw material for the Cu thin film 33 embedded in each recess 5 is dissolved. Thereby, even if the diisobutyryl methanate copper 7 (7a, 7b) has the shape which the opening width of the some recessed part 15 has the fineness of 100 nm or less, and a high aspect ratio of about 10-15, for example. , The inside can be filled with almost no gap. Further, the diisobutyryl methanate copper (7a, 7b) is dug down below the surface 6a of the silicon wafer 6 regardless of the material (chemical nature) of the inner surface of each recess 5 serving as the base of the Cu thin film 33. It flows into each of the recesses 5 having the above structure in a self-aligning manner and selectively. That is, the metal which is the main component of the conductor can preferentially fill the recesses 5 using the structure or physical shape of the base, regardless of the material of the base. A method for forming a conductor utilizing such a principle (a method for depositing a conductor thin film) is also referred to as a shape-sensitive deposition method.

  The inside of each recess 5 is filled with diisobutyryl methanate copper 7 (7a, 7b) sequentially from the bottom to the top (opening) with almost no gap. At the same time, from the diisobutyryl methanate copper 7 (7a, 7b) preferentially filled in the recesses 5 with almost no gap, the diisobutyryl methanate copper 7 ( Cu32 is precipitated from 7a, 7b). By this. Each recess 5 is filled with the Cu thin film 33 sequentially from the bottom to the top. As a result, even if the recess 5 is fine and has a high aspect ratio, it is efficiently and selectively embedded by the Cu thin film 33 without any gaps, regardless of the underlying material. As described above, a film formation method (deposition method) in which each recess 5 is sequentially filled or filled from the bottom to the top is also referred to as a bottom-up film formation method (bottom-up deposition method). it can.

  In addition, the method for forming a conductor according to this embodiment that combines a supercritical fluid and a shape-sensitive deposition method is less likely to contain impurities as compared to the CVD method. In addition, since the method of forming a conductor according to the present embodiment is a much higher density process than the PVD method or the CVD method, a complicatedly shaped recess 15 having a high aspect ratio can be embedded easily and complicatedly. It is possible to create a simple-shaped part at a higher speed. In other words, the method for forming a conductor according to the present embodiment has a higher throughput than the PVD method or the CVD method. For example, in the PVD method or the CVD method, a conductor film is formed not only on the recess but also on the entire surface of the layer where the recess is formed. On the other hand, the conductor forming method of the present embodiment can selectively form a conductor film only inside or near the recess 15, so that the raw material is smaller than that of the PVD method or the CVD method. In addition to being wasted, it is possible to omit processes such as the overall CMP process. That is, the method for forming a conductor according to the present embodiment has higher production efficiency than the PVD method or the CVD method.

  In addition, in the metal organic chemical vapor deposition method using a liquid source, the liquid source is chemically unstable and the process margin is small, whereas in the method of forming a conductor according to this embodiment, the source is chemically stable. Large process margin. At the same time, the method for forming a conductor according to the present embodiment has a wide deposition temperature process margin because the ruthenium thin film 21 can be formed at a lower temperature than the PVD method or the CVD method. That is, the process temperature dependency can be relaxed in the method for forming a conductor according to the present embodiment. Furthermore, the method of forming a conductor according to the present embodiment has a high recovery rate of expensive and rare raw materials as compared with the PVD method and the CVD method, and can be easily reused. As described above, the method for forming a conductor according to the present embodiment is more energy efficient than the PVD method and the CVD method, and thus has high process efficiency and is friendly to the environment. Furthermore, according to the method for forming a conductor of the present embodiment, the steps can be omitted or the amount of raw material used can be suppressed or reduced as compared with the PVD method and the CVD method. Compared to the CVD method, the manufacturing cost can be easily suppressed or reduced.

  Heretofore, several techniques for using a supercritical fluid as a CVD carrier gas and techniques for using a supercritical fluid as a solvent for a sol-gel film forming method have been proposed. However, unlike the present embodiment, these techniques cannot obtain a conductive thin film in the supercritical fluid itself. On the other hand, in this embodiment, since the thin film 33 of the conductor 32 can be obtained in the supercritical fluid itself as described above, the supercritical fluid is formed when the thin film 33 of the conductor 32 is formed. There is no need for an extra step such as removal. Therefore, also in this respect, it can be said that the formation method of the conductor is high in production efficiency.

  Further, in the batch-type conductor forming method using the above-described sealed reaction vessel, solid diisobutyryl methanate copper is directly dissolved in the supercritical fluid in the reaction vessel. Solid diisobutyryl methanate copper has a low vapor pressure and is difficult to dissolve in a solvent. For this reason, even if the supercritical fluid has a high solvent ability, the diisobutyryl methanate copper may remain undissolved. That is, in the method in which solid diisobutyryl methanate copper is directly dissolved in the supercritical fluid, it is difficult to accurately control the concentration of diisobutyryl methanate copper in the supercritical fluid. As a result, it was difficult to improve the usage rate of diisobutyryl methanate copper, and it was difficult to achieve raw material saving and cost reduction.

In addition, as a technique for overcoming the disadvantages caused by using such solid raw materials, a technique using liquid raw materials has also been proposed. For example, instead of solid diisobutyrylmethanate copper 7, liquid raw materials such as liquid hexafluoroacetylacetonate copper (Cu (C ₅ HF ₆ O ₂ ) TMVS; Cu (hfac) TMVS) are used. A technique for directly dissolving in a supercritical fluid has also been proposed. However, liquid raw materials are generally low in stability and difficult to handle. In particular, hexafluoroacetylacetonate copper contains fluorine, and there is a concern about environmental effects such as fluorine contamination.

On the other hand, in this embodiment, diisobutyryl methanate copper 7 is dissolved in the supercritical CO ₂ fluid 8 and introduced into the pressure resistant reactor 2 in a substantially liquid state. At this time, the diisobutyryl methanate copper 7 is dissolved in the acetone 21 in advance before the diisobutyryl methanate copper 7 is dissolved in the supercritical CO ₂ fluid 8. As described above, solid diisobutyryl methanate copper 7 has a small vapor pressure, difficult to dissolve in solvent, but readily soluble in the supercritical CO ₂ fluid 8 by using an auxiliary solvent such as acetone 21 Can be made. Simultaneously, the diisobutyryl methanate copper 7 prior to dissolving in the supercritical CO ₂ fluid 8, hydrogen 31 to facilitate dissolving the diisobutyryl methanate copper 7 in the supercritical CO ₂ fluid 8 pre It is dissolved in the supercritical CO ₂ fluid 8. Then, the diisobutyryl methanate copper 7 dissolved in the acetone 21 is dissolved in the supercritical CO ₂ fluid 8 in which hydrogen is dissolved, and then introduced into the pressure resistant reactor 2.

According to such a method, the solid diisobutyryl methanate copper 7 can be dissolved in the supercritical CO ₂ fluid 8. As a result, the originally solid diisobutyryl methanate copper 7 can be introduced into the pressure resistant reactor 2 in a substantially liquid state.

In this embodiment, the diisobutyryl methanate copper 7 and the supercritical CO ₂ fluid 8 as described above are supplied into the pressure resistant reactor 2 and the diisobutyryl methanate copper from the pressure resistant reactor 2 is used. 7 and the discharge of the supercritical CO ₂ fluid 8 are continuously performed in parallel during at least the conductor forming process in which the Cu thin film 33 is embedded in each recess 5. Further, the supply amount of the diisobutyryl methanate copper 7 and the supercritical CO ₂ fluid 8 into the pressure resistant reactor 2, and the diisobutyryl methanate copper 7 and the supercritical CO ₂ fluid 8 from the inside of the pressure resistant reactor 2. The amount of discharge is adjusted to an appropriate size at any time according to the embedding state during the conductor forming process.

  According to such a method, the diisobutyryl methanate copper 7, hydrogen 31 and the like can be continuously flowed into and out of the pressure-resistant reaction vessel 2 while the conductor formation process is performed. . That is, while the conductor formation process is performed, diisobutyryl methanate copper 7, hydrogen 31 and the like can be quantitatively and continuously supplied into the pressure resistant reactor 2. Specifically, the temperature, pressure, concentration and amount of diisobutyryl methanate copper 7, concentration and amount of hydrogen 31, and the like, which are film formation parameters of the conductive thin film 33, are accurately measured as needed. The conductor formation process can proceed in an appropriate state by controlling. Moreover, according to this embodiment, the diisobutyryl methanate copper 7 used as the raw material of the conductor 33 can be continuously supplied into the pressure resistant reactor 2. For this reason, the conductor formation process of this embodiment of the flow method (distribution method) is different from the conventional batch method (sealing method) in which the conductor formation process ends when the raw material in the reaction vessel is used up. There is virtually no limitation on the thickness of the conductive thin film 33.

  As a result, according to the present embodiment, the conductor thin film 33 having a desired film thickness is formed in each recess 5 of the silicon wafer 6 by controlling the conductor formation process with high accuracy and proceeding in an appropriate state. The diisobutyryl methanate copper 7 used in this embodiment is a fluorine-free metal compound until it can be embedded more quickly and easily. For this reason, unlike hexafluoroacetylacetonate copper and the like, there is almost no concern about environmental influences such as fluorine contamination.

Further, the conductor forming apparatus 1 and the conductor forming method according to the present embodiment have the following effects in addition to the various features described above. For example, since the flow path of the supercritical CO ₂ fluid 8 of the conductor forming apparatus 1 is closed from the supply apparatus 3 to the discharge apparatus 4, there is almost no possibility that impurities are mixed in the flow path. For this reason, there is almost no possibility that the quality of the silicon wafer 6 in which the Cu thin film 33 is embedded in each recess 5 is deteriorated by the conductor forming process. Diisobutyrylmethanate copper 7 has a higher decomposition temperature and lower vapor pressure than general CVD raw materials such as hexafluoroacetylacetonate copper. Not used. In contrast, in this embodiment, diisobutyryl methanate copper 7 can be used. That is, in this embodiment, since a raw material not used in the chemical vapor deposition method such as a solid organic metal raw material such as a CVD method can be used, the degree of freedom of the raw material is larger than that in the CVD method. Further, in this embodiment, the raw material density is 10 ⁴ to 10 ⁶ times as high as that of a conventional thin film forming method such as a CVD method. For this reason, micro electronic mechanical systems (MEMS) and nano electronic mechanical systems (NEMS) have high aspect ratios, complex structures, and extremely fine machines and components. Can be created quickly and easily. That is, this embodiment can be applied to the manufacture of machines and parts of various sizes, and is a highly scalable process.

According to another experiment conducted by the present inventors, when another supercritical fluid such as argon (Ar) having no solvent ability is used instead of carbon dioxide, continuous Cu as in this embodiment is used. Instead of the thin film 33, only a granular deposit with many impurities could be obtained. According to the inventors' consideration on this result, it is assumed that the supercritical CO ₂ fluid 8 positively contributes to the film formation process, such as reduction of impurities in the Cu thin film 33 deposited in each recess 5. Is done. Also in this respect, it can be seen that the conductor forming process of this embodiment is completely different in principle from a simple high-pressure CVD method or the like.

(Second Embodiment)
Next, a second embodiment according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same part as 1st Embodiment mentioned above, and those detailed description is abbreviate | omitted. In the present embodiment, a case where a Cu thin film 33 made of Cu32 as a conductor is provided in each recess 5 of the silicon wafer 6 will be described more specifically.

First, as shown in FIG. 10, a silicon wafer 6 used in this embodiment is specifically a silicon dioxide film (SiO ₂ film) 42 as an insulating film on a silicon layer (Si layer) 41 as a substrate body. Based on the configuration provided with A plurality of fine recesses 5 having a high aspect ratio are formed in the silicon dioxide film 42. Each recess 5 has a width of about 100 nm and a depth of about 500 nm. That is, the aspect ratio of each recess 5 is about 5.

  Prior to providing the Cu thin film 33 in each recess 5, a titanium nitride (TiN) thin film 43 is entirely formed on the surface of the silicon dioxide film 42 including the inner surface of each recess 5 by, for example, the CVD method. Coat on.

  Further, as the metal compound containing Cu as a raw material of the Cu thin film 33, diisobutyryl methanate copper 7 is used as in the first embodiment. Moreover, the pressure (total pressure) of the atmosphere in the pressure resistant reactor 2 is set to about 8.0 MPa. At the same time, the temperature of the atmosphere in the pressure resistant reactor 2 is set to about 280 ° C. The addition pressure of hydrogen 31 is set to about 0.3 MPa. Furthermore, the processing time for forming (depositing) the Cu thin film 33 was set to about 15 minutes. Under such conditions, the conductor forming method using the conductor forming apparatus 1 described in the first embodiment is executed. As a result, as shown in FIG. 10, the Cu thin film 33 could be selectively deposited inside and above some of the recesses 5.

  As described above, according to the second embodiment, the inside of each recess 5 can be preferentially embedded by the bottom-up film formation method (bottom-up deposition method) using the Cu thin film 33. Further, the Cu thin film 33 having the shape as shown in FIG. 10 can never be obtained by the CVD method or the PVD method, as can be easily understood by those skilled in the art.

(Third embodiment)
Next, a third embodiment according to the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the same part as each 1st and 2nd embodiment mentioned above, and those detailed description is abbreviate | omitted. In the present embodiment, the case where a thin film 33 made of Cu32 as a conductor is provided in each recess 5 of the silicon wafer 6 will be described more specifically.

First, in this embodiment, a silicon wafer 6 having the same configuration as that of the second embodiment described above is used. Moreover, as a metal compound containing Cu32 which is a raw material of the Cu thin film 33, diisobutyryl methanate copper 7 is used as in the first embodiment. The supply concentration of diisobutyryl methanate copper 7 into the pressure resistant reactor 2 is set to about 8.83 × 10 ⁻⁵ mol%. Moreover, the pressure (total pressure) of the atmosphere in the pressure resistant reactor 2 is set to about 8.0 MPa. At the same time, the temperature of the atmosphere in the pressure resistant reactor 2 is set to about 280 ° C. Further, the addition pressure of hydrogen 31 is set to about 0.3 MPa, and the concentration of hydrogen 31 in the pressure resistant reactor 2 is set to about 1.2 mol%. Under such conditions, the conductor forming method using the conductor forming apparatus 1 described in the first embodiment was executed. However, the conductor forming process was executed by setting the time for depositing the Cu thin film 33 in two ways of about 60 minutes and about 90 minutes.

  FIGS. 11A and 11B show the results of the conductor formation process when the deposition time of the Cu thin film 33 is set to about 60 minutes. In addition, FIG.11 (b) is sectional drawing which expands and shows each recessed part 5 vicinity of Fig.11 (a). As can be seen from FIGS. 11A and 11B, it can be seen that the inside of each recess 5 is buried by the Cu thin film 33. Further, the Cu thin film 33 overflowing to the outside of each recess 5 is formed so as to cover the entire surface 6a of the silicon dioxide film 42 (silicon wafer 6).

  12A and 12B show the results of the conductor forming process when the deposition time of the Cu thin film 33 is set to about 90 minutes. FIG. 12B is an enlarged cross-sectional view showing the vicinity of each concave portion 5 in FIG. As is apparent from FIGS. 12A and 12B, the inside of each recess 5 is embedded with the Cu thin film 33 in the same manner as when the deposition time of the Cu thin film 33 is set to about 60 minutes. I understand that. Further, the Cu thin film 33 overflowing to the outside of each recess 5 is formed so as to cover the entire surface 6a of the silicon dioxide film 42 (silicon wafer 6). Further, the Cu thin film 33 on the silicon dioxide film 42 is thicker by the amount of about 30 minutes longer than the case where the deposition time of the Cu thin film 33 is set to about 60 minutes.

  Next, the results of experiments conducted by the present inventors will be described with reference to FIGS. 13 to 17 for the film formation characteristics (deposition characteristics) of the Cu thin film 33 by the above-described conductor formation process. However, in order to clarify the change in the film thickness of the Cu thin film 33 due to the difference in the deposition time, the deposition time of the Cu thin film 33 was set to two types of about 60 minutes and about 120 minutes. Further, when the deposition time was set to about 60 minutes, the film forming temperature was set to about 240 ° C. On the other hand, the film forming temperature when the deposition time was set to about 120 minutes was set to about 240 ° C. as in the case described above.

First, as shown in FIG. 13, the inventors cut the silicon wafer 6 on which the Cu thin film 33 was deposited by the above-described conductor forming process into a strip shape of about 10 mm × 40 mm. At this time, the silicon wafer 6 was cut so that the longitudinal direction of the strip-shaped silicon wafer 6 was along the flow direction of the supercritical CO ₂ fluid 8 indicated by the solid arrow in FIG. Then, the film thickness distribution of the Cu thin film 33 on the silicon wafer 6 cut into the strip shape was examined. Specifically, the Cu thin film 33 on the silicon wafer 6 is shaved at a plurality of positions indicated by solid lines in FIG. 13 from the upstream side to the downstream side along the flow direction of the supercritical CO ₂ fluid 8, The film thickness was measured using a step gauge. At this time, the interval between each position indicated by a solid line in FIG. 13 was set to about 5 mm. At the same time, the cross section of the Cu thin film 33 on the silicon wafer 6 was observed by SEM at the position indicated by the broken line in FIG. 13 from the upstream side to the downstream side along the flow direction of the supercritical CO ₂ fluid 8. The result is shown in FIG.

The graph plotted with black triangles in FIG. 14 shows the film thickness distribution of the Cu thin film 33 on the silicon wafer 6 when the deposition time is about 120 minutes. Moreover, the graph plotted by the black square in FIG. 14 shows the film thickness distribution of the Cu thin film 33 on the silicon wafer 6 when the deposition time is about 60 minutes. On the other hand, the graph plotted with black circles in FIG. 14 shows solid hexafluoroacetylacetonate copper (Cu (C ₅ HF ₆ O ₂ ) ₂ ; Cu (hfac) ₂ as a raw material for the Cu thin film. ) Is dissolved in the supercritical CO ₂ fluid 8 to show a film thickness distribution when a Cu thin film is formed. The film formation process using this hexafluoroacetylacetonate copper was performed by setting the film formation temperature to about 300 ° C. and the film formation time to about 30 minutes.

As is apparent from the three graphs shown in FIG. 14, only when hexafluoroacetylacetonate copper is used as the raw material for the Cu thin film, from the upstream side to the downstream side along the flow direction of the supercritical CO ₂ fluid 8. The tendency for the film thickness of Cu thin film to become thin appeared as it went to. On the other hand, when the solid diisobutyryl methanate copper 7 dissolved in acetone 21 is used as the raw material for the Cu thin film 33, it is downstream from the upstream side along the direction of the flow of the supercritical CO ₂ fluid 8. There was a tendency that the film thickness of the Cu thin film 33 became thicker toward the side. When solid diisobutyryl methanate copper 7 dissolved in acetone 21 is used as a raw material for the Cu thin film 33, the deposition time is about 120 minutes as compared with the case where the deposition time is about 60 minutes. It can be seen that the film thickness of the Cu thin film 33 is thicker on the entire surface of the silicon wafer 6. That is, when solid diisobutyryl methanate copper 7 dissolved in acetone 21 is used as a raw material for the Cu thin film 33, it can be seen that there is a proportional relationship in which the film thickness increases as the deposition time increases. .

  According to research conducted by the present inventors, such a phenomenon is caused when a solid diisobutyryl methanate copper 7 dissolved in acetone 21 is used as a raw material for the Cu thin film 33 and a conductor forming process is performed. It was found that the main reason is that the concentration distribution of the diisobutyryl methanate copper 7 is biased in the pressure-resistant reaction vessel 2 during this time. If this mechanism is illustrated in a simplified and easy-to-understand manner, it can be expressed as shown in FIG.

FIG. 15 is a graph showing the concentration gradient of diisobutyryl methanate copper 7 in the pressure resistant reactor 2 during the conductor formation process along the flow direction of the supercritical CO ₂ fluid 8. It is. According to the graph shown in FIG. 15, the concentration of diisobutyryl methanate copper 7 in the pressure resistant reactor 2 during the conductor forming process is maximized on the supply port 9 side of the pressure resistant reactor 2. It turns out that it becomes small as it goes to the discharge port 10 side of the pressure | voltage resistant reaction container 2. FIG. This is because the diisobutyryl methanate copper 7 is formed in order from the upstream side to the downstream side along the flow of the supercritical CO ₂ fluid 8 in the pressure resistant reactor 2 during the conductor formation process. This is thought to be due to consumption. That is, it is considered that each recess 5 formed in the silicon wafer 6 is filled with the Cu thin film 33 in order from the upstream side to the downstream side along the flow of the supercritical CO ₂ fluid 8.

However, during the conductor formation process, the diisobutyryl methanate copper 7 is flowed from the upstream side to the downstream side along the flow of the supercritical CO ₂ fluid 8. For this reason, as the supercritical CO ₂ fluid 8 flows from the downstream side toward the upstream side, the Cu thin film 33 is less likely to be deposited on the outside of each recess 5. That is, the Cu thin film 33 becomes difficult to deposit on the surface 6 a of the silicon wafer 6 as it goes from the downstream side to the upstream side of the flow of the supercritical CO ₂ fluid 8. The diisobutyryl methanate copper 7 that flows from the upstream side to the downstream side along the flow of the supercritical CO ₂ fluid 8 easily adheres to the downstream surface of the silicon wafer 6. As a result, the Cu thin film 33 is deposited thicker from the upstream side (supply port 9 side) to the downstream side (discharge port 10 side) along the flow direction of the supercritical CO ₂ fluid 8. Such a mechanism agrees well with the tendency of each graph shown in FIGS.

Therefore, according to experiments conducted by the present inventors, when performing the conductor formation process of the present embodiment, the uppermost stream along the direction of the flow of the supercritical CO ₂ fluid 8 in the pressure resistant reactor 2 is shown. It can be seen that the concentration and amount of the diisobutyryl methanate copper 7 supplied into the pressure-resistant reaction vessel 2 may be set so that the inside of the concave portion 5 located in the portion can be filled with almost no gap. According to such a setting, not only the recess 5 located in the most upstream part along the flow direction of the supercritical CO ₂ fluid 8 but also all the recesses 5 formed in the silicon wafer 6 are formed in the Cu thin film. 33 can be filled with almost no gap.

Next, the raw material usage rate of the conductor forming process in the experiment conducted by the present inventors will be described. Specifically, as described in the first embodiment, the concentration of diisobutyryl methanate copper 7 in the supercritical CO ₂ fluid 8 before being subjected to the conductor formation process is measured by the absorbance analyzer 29. . At the same time, the concentration of diisobutyryl methanate copper 7 in the supercritical CO ₂ fluid 8 after being subjected to the conductor formation process is measured by the separator 28. And the density | concentration difference of these diisobutyryl methanate copper 7 is calculated | required. Thereby, the usage rate of the diisobutyryl methanate copper 7 in the conductor forming process using the conductor forming apparatus 1 is obtained. According to the measurement results performed by the present inventors, it was found that the usage rate of diisobutyryl methanate copper 7 in the conductor forming process using the conductor forming apparatus 1 was about 90% or more. This is a high value in each stage as compared with general film forming processes such as CVD and PVD. That is, the conductor forming process using the conductor forming apparatus 1 is very efficient and can save raw materials.

Further, in FIG. 16, the concentration of diisobutyryl methanate copper 7 in the supercritical CO ₂ fluid 8, which has been subjected and before being subjected to the conductor forming process, shown respectively using photographs. A test tube 45 on the left side in FIG. 16 is a test tube in which a solution 46 of diisobutyryl methanate copper 7 before being subjected to the conductor forming process is put. On the other hand, the test tube 47 on the right side in FIG. 16 is a test tube in which a solution 48 of diisobutyryl methanate copper 7 after being subjected to the conductor forming process is put. In the photograph shown in FIG. 16, in each of the test tubes 45 and 47, a reagent having a deep blue color is placed as the concentration of the diisobutyryl methanate copper 7 in the respective solutions 46 and 48 increases.

  As is apparent from the photograph shown in FIG. 16, the solution 46 of diisobutyryl methanate copper 7 placed in the test tube 45 is dark in color. As a result, the solution 46 of the diisobutyryl methanate copper 7 before being subjected to the conductor forming process has a high concentration of diisobutyryl methanate copper 7 and the diisobutyryl methanate copper 7 is hardly consumed. I understand. As a result, it can be seen that the diisobutyryl methanate copper 7 is almost unreacted and chemically stable before being subjected to the conductor formation process. On the other hand, the solution 48 of diisobutyryl methanate copper 7 put in the test tube 47 has a light color and is almost colorless and transparent. As a result, the solution 48 of the diisobutyryl methanate copper 7 after being subjected to the conductor formation process has a low concentration of diisobutyryl methanate copper 7 and the diisobutyryl methanate copper 7 is almost consumed. I understand. That is, according to the photograph shown in FIG. 16, the usage rate of the diisobutyryl methanate copper 7 in the conductor forming process using the conductor forming apparatus 1 is extremely high, and almost all of the diisobutyryl methanate copper 7 has a withstand voltage. It turns out that it is consumed by the conductor formation process in the reaction container 2. FIG.

Furthermore, the present inventors also calculated the change in enthalpy when various additives were added to the supercritical CO ₂ fluid 8. The calculation results are shown in FIG. The graph shown in FIG. 17, the additive does not contain supercritical CO ₂ fluid 8, supercritical CO ₂ fluid 8 Acetone 21 is added, and ethanol supercritical CO ₂ fluid 8 that is added each pressure reaction vessel The result of having measured about the change of the enthalpy at the time of flowing in in 2 is shown. According to the graph shown in FIG. 17, when executing the conductor forming process, when acetone was added 21 in the supercritical CO ₂ fluid 8, compared with the supercritical CO ₂ fluid 8 additive does not contain It can be seen that about 1,27 times the amount of heat is required.

According to research conducted by the present inventors, it is considered that such a rapid change in enthalpy may be related to the film thickness distribution of the Cu thin film 33 shown in FIG. Specifically, when the supercritical CO ₂ fluid 8 to which acetone 21 is added is used, the temperature in the vicinity of the supply port 9 rapidly decreases when the supercritical CO ₂ fluid 8 flows into the pressure resistant reactor 2. Thereby, the Cu thin film deposition reaction in the vicinity of the supply port 9 in the pressure-resistant reaction vessel 2 becomes dull. As a result, the film thickness of the Cu thin film 33 is thin near the supply port 9 and thick near the discharge port 10. That is, as described above, the thickness of the Cu thin film 33 increases from the upstream side to the downstream side of the flow of the supercritical CO ₂ fluid 8.

  As described above, according to the third embodiment, the same effects as those of the second embodiment described above can be obtained. In addition, according to the present embodiment, not only can each recessed portion 5 formed in the silicon wafer 6 be selectively filled with the Cu thin film 33, but also the silicon wafer 6 can be formed in the same manner as in a normal CVD method or PVD method. The Cu thin film 33 can be deposited on the entire surface 6a.

(Fourth embodiment)
Next, a fourth embodiment according to the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the same part as each 1st-3rd embodiment mentioned above, and those detailed description is abbreviate | omitted. In this embodiment, unlike each of the first to third embodiments, the supercritical CO ₂ fluid or the like is preheated to a predetermined temperature prior to introduction into the reaction vessel. Thereby, it is intended to obtain a better embedded state and film formation result. This will be specifically described below.

  First, FIG. 18 shows a simplified main part of the conductor forming apparatus 101 according to the present embodiment. In the conductor forming apparatus 101 of this embodiment, unlike the conductor forming apparatus 1 of the first embodiment, the substance introduced into the pressure resistant reaction container 2 is introduced into the pressure resistant reaction container 2. A preheating device (preheat system, preheat unit) 102 that is preliminarily heated to a predetermined temperature is connected immediately upstream of the pressure-resistant reaction vessel 2. In addition, although illustration is abbreviate | omitted in FIG. 18, of course, the preheat system 102 is connected to the downstream rather than the supply apparatus 3. FIG. The preheating system 102 includes a preheating chamber (preheating chamber) 103, a fourth temperature adjusting device 104, and the like.

A supercritical CO ₂ fluid 8, a reaction accelerator (H ₂ ) 31, a precursor (diisobutyryl methanate) 7, an organic solvent (acetone) 21, and the like are supplied from the supply device 3 into the preheat chamber 103. . In the following description, each substance supplied from the supply device 3 into the preheat chamber 103 is simply abbreviated as a supercritical CO ₂ fluid 8 unless otherwise specified. The supercritical CO ₂ fluid 8 is preheated (preheated) in the preheat chamber 103 and then introduced into the pressure resistant reactor 2.

Specifically, the fourth temperature adjustment device 104 is an upper portion capable of independently heating the inside of the preheat chamber 103 from above or below, similarly to the first and third temperature adjustment devices 11 and 35 described above. The mantle heater unit 104 includes two heaters, a mantle heater 104a and a lower mantle heater 104b. The temperature in the preheat chamber 103 is heated by the mantle heater unit 104 to be raised to a predetermined temperature. However, the upper limit of the temperature in the preheat chamber 103 is set to a value lower than the temperature in the pressure-resistant reaction container 2 when the conductor formation process is performed. For example, the temperature of the supercritical CO ₂ fluid 8 in the preheat chamber 103 is preheated by the mantle heater unit 104 and is raised to a predetermined temperature of about 180 ° C. or less.

  Next, two types of experiments conducted by the present inventors using the conductor forming apparatus 101 will be described with reference to FIGS. One is an experiment for measuring the internal temperature of the pressure-resistant reaction vessel 2, and the other is an experiment for forming a Cu thin film.

First, an experiment for measuring the internal temperature of the pressure resistant reactor 2 will be described with reference to FIGS. 18 and 19. In conducting this experiment, conditions were set as described below. First, as supercritical CO ₂ fluid 8 is supplied to the preheat chamber 103, the flow rate of acetone 21 to be mixed acetone 21 added non supercritical CO ₂ fluid, and the supercritical CO ₂ fluid about 10 supercritical CO ₂ fluid set in vol%, using two types of supercritical CO ₂ fluid. Secondly, the external temperature of the pressure resistant reactor 2 is set to about 250 ° C. using a thermostat 30 (not shown). Third, the volume ratio between the pressure resistant reactor 2 and the preheat chamber 103 is set to about 1: 3. Under such settings, the inside of the preheat chamber 103 was heated using the upper and lower mantle heaters 104a and 104b, and the internal temperature (preheat temperature) of the preheat chamber 103 was changed from about 50 to about 180 ° C. Then, as shown in FIG. 18, the internal temperature of the pressure-resistant reaction vessel 2 supplied with the supercritical CO ₂ fluid 8 heated in the preheat chamber 103 is set to 2 near the inlet (supply port) 9 and near the center. Measurements were taken by thermocouple 105 at the points. The results are shown as a graph in FIG.

According to the graph shown in FIG. 19, it can be seen that when the preheat temperature reaches about 150 ° C., there is almost no difference in internal temperature at two locations near the inlet 9 and near the center of the pressure resistant reactor 2. In addition, it can be seen that such a phenomenon does not depend on the presence or absence of acetone 21 in the supercritical CO ₂ fluid 8.

  Next, an experiment for forming a Cu thin film will be described with reference to FIGS. Specifically, in this Cu thin film deposition experiment, five processing conditions (I), (II), (III), (IV), and (V) were set as shown in FIG. A conductor forming process similar to that of the first embodiment described above was performed using the conductor forming apparatus 101. The results are shown at the bottom of FIG. 20 and are shown in graphs in FIGS. 21 (a) and 21 (b). In the table shown in FIG. 20, the processing temperature refers to the internal temperature of the pressure-resistant reaction container 2 when conducting the conductor formation process, and the standard deviation refers to the variation in the thickness of the deposited Cu thin film. In addition, both the two graphs shown in FIG. 21A show the film formation results when the preheating is not performed, and the three graphs shown in FIG. 21B each form the film formation when the preheating is performed. Results are shown.

According to the table shown in FIG. 20, when preheating is not performed, it can be seen that the higher the processing temperature, the greater the variation in the thickness of the Cu thin film formed on the silicon wafer. Further, according to the graph shown in FIG. 21 (a), when preheating is not performed, silicon is gradually moved from the vicinity of the inlet 9 of the pressure resistant reactor 2 toward the center and the vicinity of the outlet (discharge port) 10. It can be seen that the Cu thin film formed on the wafer is thicker. That is, it can be seen that the Cu thin film tends to deposit thicker from the upstream side toward the downstream side along the flow direction of the supercritical CO ₂ fluid 8. It can also be seen that the tendency is more prominent as the processing temperature is higher. Furthermore, it can also be seen that the higher the processing temperature, the thicker the Cu thin film.

On the other hand, according to the table shown in FIG. 20, when preheating is performed, the film thickness variation of the Cu thin film formed on the silicon wafer is not necessarily proportional to the processing temperature. I understand. It can also be seen that when preheating is performed, the variation in the film thickness of the Cu thin film can be suppressed to less than about 1/10 at the maximum, compared with the case where preheating is not performed. For example, when the processing temperature is set to about 240 ° C., it can be seen that the variation in the thickness of the Cu thin film can be suppressed to about 1/7. Further, according to the graph shown in FIG. 21B, when preheating is performed, the film thickness of the Cu thin film formed on the silicon wafer is from the vicinity of the inlet 9 to the center and the outlet of the pressure resistant reactor 2. It can be seen that the size is substantially the same over 10 and is made much more uniform than when no preheating was performed. That is, it can be seen that the Cu thin film tends to deposit with a substantially uniform film thickness regardless of the position of the flow of the supercritical CO ₂ fluid 8. However, even when preheating is performed, it can be seen that the Cu thin film becomes thicker as the processing temperature is higher, as in the case where preheating is not performed.

  Next, FIGS. 22A, 22B, and 22C show on the silicon wafer 6 under the processing conditions (II) among the processing conditions (I) to (V) in the table shown in FIG. The SEM photograph of the result of forming the Cu thin film 33 is shown. More specifically, FIG. 22A shows an SEM photograph of a cross section of the silicon wafer 6 near the entrance 9 of the pressure resistant reactor 2 and the Cu thin film 33 formed thereon. FIG. 22B shows an SEM photograph of a cross section of the silicon wafer 6 and the Cu thin film 33 formed thereon in the vicinity of the central portion of the pressure resistant reactor 2. Further, FIG. 22C shows a SEM photograph of a cross section of the silicon wafer 6 and the Cu thin film 33 formed thereon in the vicinity of the outlet 10 of the pressure resistant reactor 2. The silicon wafer 6 used in this experiment has the same structure as the silicon wafer 6 described in the second embodiment.

  As is clear from the SEM photographs shown in FIGS. 22A, 22B, and 22C, the Cu thin film 33 is formed on the silicon wafer in the vicinity of the inlet 9, the center, and the outlet 10 of the pressure resistant reactor 2. 6 is formed on the entire surface 6a of the film 6. Moreover, the inside of each recessed part 5 formed in the silicon wafer 6 is filled with the Cu thin film 33, and it turns out that the embedding property is favorable. However, regardless of the position on the surface 6 a of the silicon wafer 6, many particulate Cu deposits 106 made of abnormally grown Cu 32 are observed on the surface of the Cu thin film 33. Moreover, although the Cu thin film 33 is formed as a continuous film on the entire surface 6a of the silicon wafer 6, many irregularities are observed on the surface. As described above, when the Cu thin film 33 is formed under the processing condition (II) that does not involve preheating, the film quality is not necessarily formed as a good quality as a whole.

  Next, FIGS. 23A, 23B, and 23C show on the silicon wafer 6 under the processing conditions (V) among the processing conditions (I) to (V) in the table shown in FIG. The SEM photograph of the result of forming the Cu thin film 33 is shown. More specifically, FIG. 23A shows an SEM photograph of a cross section of the silicon wafer 6 and the Cu thin film 33 formed thereon in the vicinity of the inlet 9 of the pressure resistant reactor 2. FIG. 23B shows an SEM photograph of a cross section of the silicon wafer 6 and the Cu thin film 33 formed thereon in the vicinity of the central portion of the pressure resistant reactor 2. Further, FIG. 23C shows an SEM photograph of a cross section of the silicon wafer 6 in the vicinity of the outlet 10 of the pressure resistant reactor 2 and the Cu thin film 33 formed thereon.

  As is apparent from the SEM photographs shown in FIGS. 23A, 23B, and 23C, when the Cu thin film 33 is formed under the processing conditions (V) in the table shown in FIG. Similar to the case where the Cu thin film 33 is formed under the processing conditions, the Cu thin film 33 is entirely formed on the surface 6 a of the silicon wafer 6 in the vicinity of the entrance 9, the center, and the exit 10 of the pressure resistant reactor 2. It is formed into a film. Similarly to the case where the Cu thin film 33 is formed under the processing condition (II), the inside of each recess 5 formed in the silicon wafer 6 is filled with the Cu thin film 33, and the embedding property is also good. I understand. However, when the Cu thin film 33 is formed under the processing condition (V), unlike the case where the Cu thin film 33 is formed under the processing condition (II), regardless of the position on the surface 6a of the silicon wafer 6, The particulate Cu deposit 106 made of abnormally grown Cu 32 is hardly observed on the surface of the Cu thin film 33. Further, almost no irregularities are observed on the surface of the Cu thin film 33. Thus, when the Cu thin film 33 is formed under the processing condition (V) with preheating, compared to the case where the Cu thin film 33 is formed under the processing condition (II) without preheating, It can be seen that the Cu thin film 33 with improved film quality can be formed.

As described above, according to the fourth embodiment, the same effects as those of the first to third embodiments described above can be obtained. In addition, prior to the introduction of the supercritical CO ₂ fluid 8 to which acetone 21 has been added into the pressure-resistant reaction vessel 2, preheating is performed in advance to increase the reaction rate by performing preliminary reduction of copper. Thereby, the tendency for the Cu thin film 33 to be deposited thicker from the upstream side to the downstream side along the flow direction of the supercritical CO ₂ fluid 8 can be improved. As a result, regardless of the position in the pressure resistant reactor 2, the Cu thin film 33 having a uniform and substantially uniform film thickness can be formed almost entirely on the surface 6 a of the silicon wafer 6.

  Further, when the preheating system 102 is used as a reaction promoting medium, effects such as thermal reaction promotion and intermediate reactant generation can be obtained simply by performing preheating. These effects are obtained by preliminarily depositing a metal serving as a catalyst material such as platinum (Pt), palladium (Pd), nickel (Ni), or copper (Cu) in advance in the preheating chamber 103 before performing preheating. It becomes more prominent when it is provided inside. In this case, although not shown in the drawing, these metals are formed into, for example, a plate shape or a wire shape and disposed inside the preheat chamber 103, vapor deposited on the inner wall surface of the preheat chamber 103, or the preheat chamber 103. It may be placed on or suspended on a support made of a porous body or the like provided inside.

  Further, the preheating system 102 of the present embodiment may be used in combination with the reaction suppression unit 34 described in the first embodiment. In this case, the preheating system 102 may be provided between the reaction suppressing unit 34 and the pressure resistant reaction container 2. According to such a configuration, the function of the reaction suppressing unit 34 and the function of the preheat system 102 can be exhibited without contradicting each other.

Note that the preheating described above does not necessarily have to be heated to around the temperature at which the conductor forming process is performed. The critical point at which acetone 21 becomes supercritical is a temperature of about 235 ° C. and a pressure of about 4.76 MPa. Therefore, the heating when using a supercritical CO ₂ fluid 8 Acetone 21 is added, so far in advance about 235 ° C. The supercritical CO ₂ fluid 8 Acetone 21 is added prior to entering the pressure-resistant reaction container 2 It is sufficient that the pressure reaches about 4.76 MPa.

(Fifth embodiment)
Next, a fifth embodiment according to the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the same part as each 1st-4th embodiment mentioned above, and those detailed description is abbreviate | omitted. In the present embodiment, unlike the first to fourth embodiments, a case will be described in which the recesses 5 of the silicon wafer 6 are embedded using a thin film made of ruthenium (Ru) instead of the Cu thin film 33.

  First, here, a silicon wafer 6 having substantially the same configuration as that of the silicon wafer 6 used in the second and third embodiments described above is used. However, unlike the silicon wafer 6 used in each of the second and third embodiments, the TiN thin film 43 is not provided on the inner surface of each recess 5 and the surface of the silicon dioxide film 42. Only the Au thin film 44 is entirely coated on the inner surface of each recess 5 and the surface of the silicon dioxide film 42. Each recess 5 is formed in the silicon dioxide film 42. The dimensions of each recess 5 are such that the bottom width is about 130 nm, the opening width is about 200 nm, and the depth is about 2 μm. That is, the aspect ratio of each recess 5 is about 10-15. The above-described flow-type conductor forming process is performed on the silicon wafer 6 having such a configuration.

Here, cyclopentadienyl ruthenium (Ru (C ₅ H ₅ ) ₂ ; RuCp ₂ ), which is the same organometallic complex as diisobutyryl methanate copper 7, is used as a raw material for the Ru thin film. Then, the concentration of cyclopentadienyl ruthenium 18 in the supercritical CO ₂ fluid 8 is set to about 25 mg / cc, and the addition pressure of hydrogen 19 is set to about 1.0 MPa. Moreover, the pressure (total pressure) of the atmosphere in the pressure resistant reactor 2 is set to about 12 MPa. Moreover, the temperature in the pressure | voltage resistant reaction container 2 at the time of performing a conductor formation process is set to about 250 degreeC. Then, the processing time of the conductor forming process is set to about 15 minutes. Under these conditions, the present inventors performed the above-described conductor formation process. The results are shown in FIGS. 24 and 25 using SEM photographs. 25 is an enlarged cross-sectional view showing the vicinity of each recess 5 in FIG.

  As shown in FIGS. 24 and 25, mushroom-shaped Ru thin films (ruthenium islands) 51 could be selectively formed along the concave portions 5 on the Au thin film 44 constituting the surface 6 a of the silicon wafer 6. It was confirmed. Moreover, as shown in FIG. 24, it was confirmed that the inside of each recessed part 5 was able to be filled almost without gap from the bottom part to the upper part similarly to 3rd Embodiment mentioned above.

  As described above, according to the fifth embodiment, even if Ru is used instead of Cu, the same effects as those of the first to fourth embodiments described above can be obtained.

(Sixth embodiment)
Next, a sixth embodiment according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same part as each 1st-5th embodiment mentioned above, and those detailed description is abbreviate | omitted. In the present embodiment, a technique for manufacturing a semiconductor device using the conductor forming method described in the first embodiment will be described. Specifically, the buried electrode of the trench capacitor is formed using the above-described conductor forming method.

As shown in FIG. 26, the silicon wafer 6 used in the present embodiment has a substrate body constituted by a P-type silicon layer (Si layer) 22. The surface layer portion of the P-type silicon layer 22 is a P well 61. Then, a fine recess portion (trench) 62 having a high aspect ratio is formed inside the P well 61 which is also a surface layer portion of the silicon wafer 6. An n-type impurity is introduced into the surface layer portion inside the trench 62 by ion implantation or the like, and becomes the cathode 63 of the trench capacitor 68. Further, a silicon oxide film (SiO ₂ film) 64 serving as a capacitive insulating film is provided inside the trench 62 so as to cover the surface of the cathode 63. Further, in the surface layer portion of the silicon wafer 6, an element isolation region 65 and an n ⁺ -type impurity diffusion region 66 that becomes a source region or a drain region of a transistor (not shown) are formed.

  After the silicon wafer 6 having such a structure is accommodated in the pressure resistant reactor 2, the conductor forming method described in the first embodiment is executed. At this time, when the conductor provided in the trench 62 is formed of Cu, any one of the processing conditions in the second to fourth embodiments described above may be employed. Further, when the conductor provided in the trench 62 is formed of Ru, the processing conditions of the fifth embodiment described above may be employed. Here, the trench 62 is filled with the Ru thin film 67. As a result, the Ru thin film 67 serving as the buried electrode of the trench capacitor 68 can be formed selectively and in the vicinity of the opening of the trench 62 having a fine and high aspect ratio and with almost no gap. After the film formation process of the Ru thin film 67 is completed, the silicon wafer 6 is taken out from the inside of the pressure resistant reactor 2, and the Ru thin film 67 is formed into a desired embedded electrode shape by an etching process or the like. Thus, a plate electrode 67 as a buried electrode formed in a desired shape using a Ru thin film is provided on the surface layer portion of the silicon wafer 6. As a result, a trench capacitor 68 including a cathode 63, a capacitive insulating film 64, and a plate electrode 67 is provided on the surface layer portion of the silicon wafer 6.

  Thereafter, on the surface 6a of the silicon wafer 6 provided with the trench capacitor 68, the word 69, the bit line 70, the contact plug 71 for obtaining conduction between the bit line 70 and the impurity diffusion region 66 by a known technique, and An interlayer insulating film 72 or the like may be provided. Note that, like the plate electrode 67, the contact plug 71 may be formed by the conductor forming method described in the first embodiment. Through the steps so far, the semiconductor device 73 having the structure shown in FIG. 26 is obtained.

  As explained above, according to the sixth embodiment, the same effects as those of the first to fifth embodiments described above can be obtained. Also, the trench capacitor 68 including the plate electrode 67 having a three-dimensional and complicated shape can be efficiently and easily formed. As a result, the semiconductor device 73 including the trench capacitor 68 can be manufactured efficiently and easily. Such a semiconductor device 73 can be manufactured at low cost because the production efficiency is good and the manufacturing process can be simplified.

(Seventh embodiment)
Next, a seventh embodiment according to the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the same part as each 1st-6th embodiment mentioned above, and those detailed description is abbreviate | omitted. In the present embodiment as well, as in the sixth embodiment described above, a technique for manufacturing a semiconductor device using the conductor forming method described in the first embodiment will be described. However, in the present embodiment, unlike the sixth embodiment, the multilayer wiring structure is formed using the above-described conductor forming method.

  First, as shown in FIG. 27A, a case will be described in which a multilayer wiring structure including an upper layer wiring having a so-called single damascene structure in which wirings and plugs are formed separately is formed.

  First, the first interlayer insulating film 42a is provided on the substrate body 41 of the silicon wafer 6 by a well-known CVD method. Subsequently, a lower layer wiring forming recess 81 for providing a first layer wiring 83 serving as a lower layer wiring is formed in the first layer interlayer insulating film 42a by a known etching process or the like. Subsequently, the lower layer wiring barrier metal film 82 and the lower layer wiring Cu film 83 are embedded in the lower layer wiring forming recess 81 by a known CVD method, CMP method or the like. As a result, a first-layer wiring 83 serving as a lower-layer wiring is provided in the first-layer interlayer insulating film 42a.

  Subsequently, an interlayer insulating film 42b on the lower layer side of the second interlayer insulating film is provided on the first interlayer insulating film 42a provided with the lower Cu wiring 83 by a well-known CVD method. Subsequently, a via hole 84 for providing a via plug 86 for obtaining electrical continuity between the lower layer Cu wiring 83 and the upper layer wiring 99 is formed in the second layer lower interlayer insulating film 42b by a known etching process or the like. . Subsequently, a via plug barrier metal film 85 is formed on the surface of the second lower interlayer insulating film 42 b including the inner surface of the via hole 84 by a known CVD method or the like.

  Subsequently, the silicon wafer 6 provided with the barrier metal film 85 is accommodated in the pressure resistant reactor 2. Thereafter, the conductor forming method described in the first embodiment is executed. At this time, when the via plug 86 is formed of Cu, any of the processing conditions of the second to fourth embodiments described above may be employed. As a result, a Cu film 86 serving as a via plug can be formed selectively inside and around the opening of the fine and high aspect ratio via hole 84 and with almost no gap. After the Cu film 86 is formed, the silicon wafer 6 is taken out of the pressure-resistant reaction vessel 2 and the Cu film 86 and the barrier metal film 85 are embedded in the via hole 84 by a known CMP process or the like. As a result, the Cu via plug 86 is provided in the second-layer lower interlayer insulating film 42b.

  Subsequently, an interlayer insulating film 42c on the upper layer side of the second interlayer insulating film is provided on the second lower interlayer insulating film 42b provided with the Cu via plug 86 by a well-known CVD method. . Subsequently, an upper-layer wiring formation recess 87 for providing the upper-layer wiring 89 is formed in the second-layer upper interlayer insulating film 42c by a known etching process or the like. Subsequently, an upper-layer wiring barrier metal film 88 is formed on the surface of the second-layer upper-layer-side interlayer insulating film 42c including the inner surface of the upper-layer wiring forming recess 87 by a known CVD method or the like.

  Subsequently, the silicon wafer 6 provided with the barrier metal film 88 is accommodated again in the pressure resistant reactor 2. Thereafter, the conductor forming method described in the first embodiment is executed. At this time, when the upper layer wiring 89 is formed of Cu, as in the case where the Cu via plug 86 is formed, any one of the processing conditions of the second to fourth embodiments described above may be employed. good. As a result, the Cu film 89 serving as the upper layer wiring can be formed selectively inside the fine upper layer wiring forming recess 87 and in the vicinity of the opening thereof with almost no gap. After the formation of the Cu film 89 is completed, the silicon wafer 6 is taken out from the inside of the pressure resistant reactor 2 again, and the Cu film 89 and the barrier metal film 88 are formed in the upper wiring formation recess 87 by a known CMP process or the like. Embed in. As a result, the second-layer wiring 89 formed separately from the Cu via plug 86 is provided in the second-layer upper interlayer insulating film 42c. That is, the upper layer Cu wiring 89 having a so-called single damascene structure is provided in the second layer upper interlayer insulating film 42c.

  Through the steps so far, as shown in FIG. 27A, the upper Cu wiring 89 and the lower Cu wiring 83 having a single damascene structure are made conductive through the barrier metal films 85 and 88 and the Cu via plug 86. A semiconductor device 90 having an upper and lower two-layer wiring structure is obtained.

  Next, as shown in FIG. 27B, a case will be described in which a multilayer wiring structure including an upper layer wiring having a so-called dual damascene structure in which wiring and a plug are integrally formed is described.

  First, the lower layer Cu wiring 83 is provided in the first-layer interlayer insulating film 42a by the same process as that for manufacturing the semiconductor device 90 described above.

  Subsequently, a second-layer interlayer insulating film 42d is provided on the first-layer interlayer insulating film 83a provided with the lower layer Cu wiring 83 by a well-known CVD method. Subsequently, a recess 91 for forming an upper layer wiring for providing an upper layer wiring and a via hole 92 for providing a via plug for obtaining conduction between the upper layer wiring and the lower layer Cu wiring 83 are formed in the second layer by a known etching process or the like. In the interlayer insulating film 42d of the eye, they are integrally formed in communication with each other. Subsequently, an upper wiring barrier metal film 93 is formed on the surface of the second-layer interlayer insulating film 42d including the inner surface of the via hole 92 by a known CVD method or the like.

  Subsequently, the silicon wafer 6 provided with the barrier metal film 93 is accommodated in the pressure resistant reactor 2. Thereafter, the method for selectively forming a conductor described in the first embodiment is executed. At this time, in the case where the upper layer wiring and the via plug are formed of Cu, as in the case of manufacturing the semiconductor device 90 described above, if any one of the processing conditions of the second to fourth embodiments is employed. good. As a result, the via plug 92 and the upper layer can be selectively formed in the fine and high aspect ratio via hole 92 and the upper layer wiring forming recess 91 and around the opening of the upper layer wiring forming recess 91 with almost no gap. A Cu film to be a wiring can be formed. After the Cu film formation process is completed, the silicon wafer 6 is taken out of the pressure-resistant reaction vessel 2 and the Cu film and the barrier metal film 93 are removed from the via hole 92 and the upper wiring formation recess 91 by a known CMP process or the like. Embed inside. Thus, the second layer wiring 95 formed integrally with the Cu via plug 94 is provided in the second layer interlayer insulating film 42d. That is, the upper layer Cu wiring 95 having a so-called dual damascene structure is provided in the second-layer interlayer insulating film 42d.

  As shown in FIG. 27B, the upper and lower Cu wirings 95 and the lower Cu wiring 83 having a dual damascene structure are electrically connected through the barrier metal film 93 and the Cu via plug 94 as shown in FIG. A semiconductor device 96 having a multilayer wiring structure of layers is obtained.

  Next, as shown in FIG. 28, the case where conductors are collectively provided in a plurality of recesses 5 having at least one of shape, depth, width, and aspect ratio different from each other will be described.

  First, the interlayer insulating film 42 is provided on the substrate body 41 of the silicon wafer 6 by a well-known CVD method by the same process as that for manufacturing the semiconductor devices 90 and 96 described above. Subsequently, the first to fourth wiring forming recesses 5a, 5b, 5c, 5d for providing the first to fourth wirings 97a, 97b, 97c, 97d are formed in the interlayer insulating film 42 by a known etching process or the like. Formed at multiple locations inside. As shown in FIG. 28, the second wiring formation recess 5b has the same depth as the first wiring formation recess 5a, but is wider than the first wiring formation recess 5a and has an aspect ratio. The ratio is getting smaller. The third wiring formation recess 5c has the same width as the first wiring formation recess 5a, but is deeper and has a higher aspect ratio than the first wiring formation recess 5a. ing. Further, the fourth wiring forming recess 5b is shallower than the first wiring forming recess 5a, and the width of both the opening and the bottom is larger than that of the first wiring forming recess 5a. The aspect ratio is small. The first to third wiring forming recesses 5a, 5b, and 5c are rectangular in cross section, whereas the fourth wiring forming recess 5b has an opening in cross section. Has a trapezoidal shape that is upside down compared to the bottom.

  Subsequently, the silicon wafer 6 on which the first to fourth wiring forming recesses 5a, 5b, 5c, 5d are formed is accommodated in the pressure resistant reactor 2. Thereafter, the method for selectively forming a conductor described in the first embodiment is executed. At this time, when the first to fourth wirings 97a, 97b, 97c, and 97d are formed of Cu, each of the second to fourth embodiments is performed in the same manner as in the case of manufacturing the semiconductor devices 90 and 96 described above. Any one of the processing conditions may be adopted. Accordingly, the inside of the plurality of recesses 5a, 5b, 5c, and 5d having at least one of shape, depth, width, and aspect ratio different from each other and around the opening thereof are selectively and almost The Cu film 97 can be formed in a lump without creating a gap. After the film formation process of the Cu film 97 is completed, the silicon wafer 6 is taken out from the inside of the pressure resistant reactor 2, and the Cu film and the barrier metal film 93 are formed in the recesses 5a, 5b, 5c, 5d by a known CMP process or the like. Embed inside.

  By the steps so far, as shown in FIG. 28, first to fourth wirings 97a, 97b, 97c, and 97d having at least one of shape, depth, width, and aspect ratio different from each other are provided. A semiconductor device 98 is obtained.

  As described above, according to the seventh embodiment, the same effects as those of the first to sixth embodiments described above can be obtained. That is, the semiconductor devices 90 and 96 having a fine multilayer wiring structure having a size of 100 nm or less can be obtained. In addition, the conductors 97 can be collectively provided in the plurality of fine recesses 5 having at least one of shape, depth, width, and aspect ratio different from each other. Therefore, according to this embodiment, it is possible to efficiently and easily manufacture the semiconductor devices 90, 96, and 98 having a fine and complicated shape at the nano-size level. Of course, like the upper layer Cu wirings 89 and 95 and the Cu via plugs 86 and 94, the lower layer Cu wiring 83 may be formed by the conductor forming method described in the first embodiment.

(Eighth embodiment)
Next, an eighth embodiment according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same part as each 1st-7th embodiment mentioned above, and those detailed description is abbreviate | omitted. This embodiment is the same as the first embodiment except that the posture of the object to be processed disposed inside the reaction vessel is different from the first embodiment described above. The following is a brief description.

As shown in FIG. 29, in this embodiment, the substrate 6 as the object to be processed is disposed inside the pressure resistant reaction container 2 with the surface 6a facing downward. At this time, more preferably, the surface 6a of the substrate 6 is directed vertically downward. Thereby, even when the mixture composed of the auxiliary solvent 21 and the supercritical CO ₂ fluid 8 is separated by gravity, the supercritical fluid can be preferentially brought into contact with the surface 6 a of the substrate 6 and the inner surfaces of the respective recesses 5. Hereinafter, the features of the face down method will be described more specifically and in detail.

  In general, since a supercritical fluid is a compressible high-density fluid, it has a feature that thermal convection is likely to occur. For this reason, when the supercritical fluid in the pressure-resistant reaction container 2 is heated, for example, the indoor layer heated by heating rises from the bottom to the top, and the thermal layer of the supercritical fluid is in the pressure-resistant reaction container 2. It will exist above. At the same time, the supercritical fluid mainly flows along the vertical direction from the bottom to the top of the pressure-resistant reaction vessel 2, so that uncontrollable oscillation and turbulence are reduced, and the conductor formation process is stabilized. To do. Accordingly, the supercritical fluid in the pressure-resistant reaction container 2 is placed by placing the substrate 6 above the inside of the pressure-resistant reaction container 2 with the surface 6a serving as a deposition surface on which the conductor 33 is deposited facing downward (vertically downward). When heated, the heating layer of the supercritical fluid preferentially contacts the surface (deposition surface) 6a of the substrate 6 and each of the recesses 5 in a stable and uniform manner, so that the heating efficiency of the substrate 6 is improved. As a result, since the precipitation reaction of the conductor 33 occurs efficiently and stably, it is possible to provide the conductor 33 more efficiently and stably inside each recess 5 and on the deposition surface (surface) 6a. it can.

  Moreover, since the supercritical fluid is a high-density fluid as described above, the raw material concentration is high. For this reason, there exists a possibility that the reaction which generate | occur | produces a particle | grain (particle) may progress by the fluctuation of the subtle density in a conductor formation process. If particles are generated during the conductor formation process, the quality of the conductor 33 is likely to deteriorate. In order to prevent such a risk, it is preferable to place the substrate 6 in the pressure resistant reactor 2 with the deposition surface 6a facing downward. By disposing the substrate 6 in such a posture, even when particles are generated, there is almost no possibility that the particles will accumulate on the deposition surface 6a or inside each recess 5. As a result, it is possible to form a homogeneous and higher-quality conductor 33 on the deposition surface 6a or inside each recess 5.

As described above, according to the eighth embodiment, the same effects as those of the first to seventh embodiments described above can be obtained. In particular, when the auxiliary solvent 21 and the supercritical CO ₂ fluid 8 are mixed and used, the substrate 6 is subjected to a pressure reaction with the surface 6a on which the concave portions 5 are formed facing downward as in this embodiment. By disposing inside the container 2, the conductor 33 can be formed more efficiently inside each recess 5.

In the present embodiment, similarly to the first embodiment described above, it is preferable that the substrate 6 is disposed at a position that does not ride on a straight line connecting the supply port 9 and the discharge port 10. In the first embodiment, as described above, the substrate 6 is disposed inside the pressure-resistant reaction container 2 with the surface 6a on which the concave portions 5 are formed facing upward, so that the substrate 6 has the surface 6a disposed on the supply port. It is preferable to be positioned below the straight line connecting 9 and the discharge port 10. As a result, the metal compound serving as a raw material for the conductor 33 without blocking the flow of the supercritical fluid 8 inside the pressure-resistant reaction vessel 2 and sufficiently securing the volume of the space above the surface 6 a of the substrate 6. 7, auxiliary solvent 21, supercritical CO ₂ fluid 8, and the like can be efficiently supplied to the surface 6 a of the substrate 6 and the inner surface of each recess 5.

On the other hand, in the present embodiment, as described above, the substrate 6 is disposed inside the pressure-resistant reaction container 2 with the surface 6a on which the recesses 5 are formed facing downward. 6a is preferably positioned above the straight line connecting supply port 9 and discharge port 10. Thereby, as in the first embodiment, the volume of the space below the surface 6a of the substrate 6 is sufficiently secured without blocking the flow of the supercritical fluid 8 inside the pressure-resistant reaction vessel 2, and conductive. The metal compound 7, the auxiliary solvent 21, the supercritical CO ₂ fluid 8, and the like that are the raw materials of the body 33 can be efficiently supplied to the surface 6 a of the substrate 6 and the inner surfaces of the recesses 5.

  Note that the conductor forming apparatus, the conductor forming method, and the semiconductor device manufacturing method according to the present invention are not limited to the first to eighth embodiments described above. Without departing from the spirit of the present invention, a part of the configuration or manufacturing process can be changed to various settings, or various settings can be appropriately combined and used. .

  For example, in each of the first to fourth embodiments, the most expected Cu thin film 33 is formed as a conductor provided in each recess 5. In the fifth embodiment, a ruthenium thin film 51 that is considered as a so-called glue film is formed as a conductor provided in each recess 5. In each of the sixth and seventh embodiments, the Cu thin films 67, 86, 89, 94, 95, and 97a are used as conductors provided in the recesses 62, 84, 87, 94, 91, and 5a to 5d. A 97d film was formed. However, the conductor provided in each of the recesses 5, 62, 84, 87, 94, 91, 5a to 5d is not necessarily limited to the Ru thin film 51 or the Cu thin films 67, 86, 89, 94, 95, and 97a to 97d. Not. The conductor provided in each of the recesses 5, 62, 84, 87, 94, 91, 5a to 5d may be, for example, a conductor whose main component is a metal belonging to a platinum group other than ruthenium. Specifically, according to the process of selectively forming a conductor according to the present invention, the conductive material mainly composed of platinum (Pt), palladium (Pd), iridium (Ir), rhodium (Rh), or osmium (Os). A body can also be provided in each recess 5, 62, 84, 87, 94, 91, 5a-5d.

The organic metal complex containing Cu 32 (precursor) is diisobutyryl methanate copper described above _{(Cu (C 7 H 15 O} 2) 2; Cu (dibm) 2) 7 is not limited to. In addition to diisobutyrylmethanate copper 7, examples of the organometallic complex containing Cu32 include hexafluoroacetylacetonate copper (Cu (C ₅ HF ₆ O ₂ ) ₂ ; Cu (hfac) ₂ ), Cu ⁺² ( Hexafluoroacetylacetonate) ₂ , Cu ⁺² (acetylacetonate) ₂ , Cu ⁺² (2,2,6,6-tetramethyl-3,5-heptanedione) _{2 and the} like can be used. Even if these organometallic complexes are used, the same effects as those of the first to fourth, sixth, and seventh embodiments can be obtained. Similarly, the organometallic complex containing ruthenium is not limited to the above-described cyclopentadienyl ruthenium (Ru (C ₅ H ₅ ) ₂ ; RuCp ₂ ). As the organometallic complex containing ruthenium, in addition to cyclopentadienylruthenium, for example, organic Ru compounds such as RuCpMe, Ru (C ₅ HF ₆ O ₂ ) ₂ ; Ru (C ₁₁ H ₁₉ O ₂ ) ₃ , and oxygen-containing compounds A Ru complex or the like can be used. Even if these organometallic complexes are used, the same effect as that of the fifth embodiment can be obtained. Moreover, the metal compound (organometallic complex) containing the metal which is the main component of these conductors does not necessarily need to be in a solid phase (solid state) before processing. The phase (state) before the treatment of the metal compound containing the metal as the main component of the conductor may be a liquid phase (liquid).

  Moreover, the conductor provided in each recessed part 5,62,84,87,94,91,5a-5d is not necessarily limited to the metal single-piece | unit which consists of single metals, such as ruthenium and copper. For example, the conductor provided in each of the recesses 5, 62, 84, 87, 94, 91, 5a to 5d may be an alloy made of two or more kinds of metals. The conductor provided in each recess 15 only needs to contain at least one metal and have conductivity. For example, in the method for selectively forming a conductor according to the present invention, an organometallic complex as a metal compound containing copper and an organometallic complex as a metal compound containing aluminum are dissolved in carbon dioxide as a supercritical fluid. In this way, an alloy of copper and aluminum can be provided in each recess 15.

The raw material for the supercritical fluid is not necessarily limited to carbon dioxide. Examples of other supercritical fluid materials include ethane (C ₂ H ₆ ), dinitrogen monoxide (N ₂ O), butane (C ₃ H ₈ ), ammonia (NH ₃ ), and hexane (C ₆ H ₁₄ ). , Methanol (CH ₃ OH), ethanol (C ₂ H ₅ OH), water (H ₂ O), and the like. Among these materials, ethane (C ₂ H ₆ ) has a critical temperature at which it becomes a supercritical fluid is about 32 ° C., and a critical pressure is about 4.9 MPa. In addition, dinitrogen monoxide (N ₂ O) has a critical temperature of about 36 ° C., which becomes a supercritical fluid, and a critical pressure of about 7.2 MPa. That is, ethane (C ₂ H ₆ ) and dinitrogen monoxide (N ₂ O) are materials that are as easy to handle as carbon dioxide.

Further, the amount of the diisobutyryl methanate copper 7 dissolved in the supercritical CO ₂ fluid 8 may not be the supersaturated state described above. Depending on the desired deposition rate of Cu32, the amount of diisobutyrylmethanate copper 7a dissolved in the supercritical CO ₂ fluid 8 may be set to a subsaturated state or a saturated state.

Further, it is not always necessary to mix hydrogen 31 which is a substance that promotes the precipitation of Cu 32 into the supercritical CO ₂ fluid 8. Instead of mixing hydrogen 31 into the supercritical CO ₂ fluid 8, as explained in the first embodiment, by changing at least one of the temperature and pressure of the atmosphere in the pressure resistant reactor 2 to make it non-uniform. The density of the supercritical CO ₂ fluid 8 may be fluctuated. Also by such a method, the density of the supercritical CO ₂ fluid 8 can be made non-uniform to cause density fluctuation, and the precipitation of Cu 32 from the diisobutyryl methanate copper 7a can be promoted. Alternatively, it may be used in combination with incorporation of hydrogen 31 to such a method and the supercritical CO ₂ fluid 8 in.

Further, it is not always necessary to mix the hydrogen 31 into the supercritical CO ₂ fluid 8 before dissolving the diisobutyryl methanate copper 7 dissolved in the acetone 21 in the supercritical CO ₂ fluid 8. Incorporation of hydrogen 31 into the supercritical CO ₂ fluid 8, for example, to dissolve the diisobutyryl methanate copper 7 dissolved in acetone 21 simultaneously and to dissolve in the supercritical CO ₂ fluid 8 or acetone 21 diisobutyrate It may be performed after dissolving the tyrylmethanate copper 7 in the supercritical CO ₂ fluid 8.

  Further, the application example of the conductor forming method according to the present invention is not limited to the semiconductor device manufacturing method described in the sixth and seventh embodiments. Other application examples of the method for selectively forming a conductor according to the present invention include, for example, a method for manufacturing a high-density magnetic recording medium (nanodot magnetic recording medium), a nonlinear optical element, or the like. Alternatively, in the method of selectively forming a conductor according to the present invention, in a step of forming a fine wiring inside a fine semiconductor element such as a CMOS, a seed film made of a conductor serving as a basis of the wiring is formed with a fine and high aspect ratio. Of course, the present invention can also be applied to a process of forming in a recess such as a hole or groove.

  Furthermore, although detailed and detailed description accompanying the illustration is omitted, according to experiments conducted by the present inventors, each of the second to fifth elements can be obtained by using the method for selectively forming a conductor according to the present invention. It has been found that a conductor can be selectively provided not only in a recess having a width of about 100 nm as in the embodiment but also in an extremely fine recess having a width of about 10 nm or less. That is, according to the method for selectively forming a conductor according to the present invention, it is virtually impossible to bury the inside without a gap by a conventional CVD method or PVD method, etc., inside an extremely fine and high aspect ratio recess. However, it has been found that the conductor can be embedded efficiently and easily without a gap. That is, it has been found that the method for selectively forming a conductor according to the present invention can be sufficiently applied to manufacturing processes of various elements and devices that require a conductor having a finer and more complicated structure and shape in the future.

The block diagram which simplifies and shows the formation apparatus of the conductor which concerns on 1st Embodiment. Sectional drawing which simplifies and shows the inside of the reaction container with which the formation apparatus of the conductor shown in FIG. 1 is provided. Sectional drawing which simplifies and shows the inside of the raw material supply apparatus with which the formation apparatus of the conductor shown in FIG. 1 is provided. The figure which shows the selection conditions of the auxiliary solvent which concerns on 1st Embodiment as a graph. The figure which shows the selection conditions of the auxiliary solvent which concerns on 1st Embodiment as a graph. The figure which shows the selection conditions of the auxiliary solvent which concerns on 1st Embodiment as a graph. Sectional drawing which shows the formation method of the conductor which concerns on 1st Embodiment. Sectional drawing which shows the formation method of the conductor which concerns on 1st Embodiment. Sectional drawing which simplifies and shows the modification of the formation apparatus of the conductor shown in FIG. Sectional drawing which shows the structure of the conductor vicinity which consists of Cu formed by the formation method of the conductor concerning 2nd Embodiment using a SEM photograph. Sectional drawing which shows the structure of the conductor vicinity which consists of Cu formed by the formation method of the conductor concerning 3rd Embodiment using a SEM photograph. Sectional drawing which shows the structure of the conductor vicinity which consists of Cu formed by the formation method of the conductor concerning 3rd Embodiment using a SEM photograph. The figure which shows how to investigate the film thickness of the conductor which consists of Cu formed by the formation method of the conductor which concerns on 3rd Embodiment. The figure which shows the film thickness of the conductor which consists of Cu investigated by the method shown in FIG. The figure which simplifies and shows the density | concentration distribution of the raw material of the conductor in the reaction container in the formation method of the conductor which concerns on 3rd Embodiment as a graph. The figure which shows the consumption state of the raw material of each conductor before implementation of the formation method of the conductor which concerns on 3rd Embodiment, and after implementation with a photograph. The figure which shows the magnitude | size of the enthalpy at the time of a supercritical fluid flowing in in the reaction container in the formation method of the conductor which concerns on 3rd Embodiment according to the presence or absence of an auxiliary solvent, and the kind of auxiliary solvent as a graph. The figure which simplifies and shows a part of conductor formation apparatus which concerns on 4th Embodiment. The figure which shows the relationship between the temperature in the preheat chamber of the conductor formation apparatus shown in FIG. 18 and the temperature in reaction container in a graph. The processing conditions when forming a conductor by the method for forming a conductor according to the fourth embodiment and the processing conditions when forming the conductor by a method for forming a conductor according to a comparative example with respect to the fourth embodiment are combined. The figure shown as a table. The figure which shows the relationship between the distance from the entrance of the reaction container at the time of forming Cu film | membrane on each process condition described in the table | surface shown in FIG. 20 is a cross-sectional view showing a film formation state in a predetermined place in the reaction vessel when a Cu film is formed under the process condition (II) among the process conditions described in the table shown in FIG. Figure. 20 is a cross-sectional view showing a film formation state in a predetermined place in the reaction vessel when a Cu film is formed under the process condition (V) among the process conditions described in the table shown in FIG. Figure. The perspective view which shows the structure of the conductor vicinity which consists of Ru formed by the formation method of the conductor which concerns on 5th Embodiment using a SEM photograph. FIG. 25 is a cross-sectional view showing an enlarged structure in the vicinity of a conductor made of Ru shown in FIG. 24 using an SEM photograph. Sectional drawing which shows the manufacturing method of the semiconductor device which concerns on 6th Embodiment. Sectional drawing which shows the manufacturing method of the semiconductor device which concerns on 7th Embodiment. Sectional drawing which shows the manufacturing method of the semiconductor device which concerns on 7th Embodiment. Sectional drawing which shows the formation method of the conductor which concerns on 8th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 ... Conductor formation apparatus, 2 ... Pressure-resistant reaction container, 3 ... Supply apparatus, 4 ... Discharge apparatus, 5, 5a, 5b, 5c, 5d ... Recessed part provided with a conductor, 6 ... Silicon wafer (to-be-processed) body), 6a ... silicon wafer surface (surface of the object), 7 ... diisobutyryl methanate copper _{(Cu (C 7 H 15 O} 2) 2; Cu (dibm) 2, fluorine-free metal compound), 7a: Liquid diisobutyryl methanate copper (Cu (C ₇ H ₁₅ O ₂ ) ₂ ; Cu (divm) ₂ , metal compound), 7b: Molecular diisobutyryl methanate copper (Cu (C ₇ H) ₁₅ O ₂ ) ₂ ; Cu (divm ₂ , metal compound), 8... Supercritical CO ₂ fluid (supercritical fluid using carbon dioxide as a raw material), 11... Mantle heater (first temperature control device), 11 a. Upper mantle heater (first temperature control device) 11b: lower mantle heater (first temperature control device), 12: supercritical fluid supply device, 13 ... raw material supply device, 14 ... reaction accelerator supply device, 15 ... siphon cylinder for supercritical fluid (supercritical fluid storage) Device, supercritical fluid supply device), 16 ... cooling device (liquefaction device, supercritical fluid supply device), 17 ... supercritical fluid delivery pump (supercritical fluid delivery device, supercritical fluid supply device), 18 ... precursor reservoir ( raw material storage device, a raw material supply device), 19 ... raw material delivery pump (feed delivery device, a raw material supply device), 20 ... raw material delivery valve (material supply device), 21 ... acetone (CH ₃ COCH _3, cosolvent), 22 ... Siphon cylinder for reaction accelerator (reaction accelerator storage device, reaction accelerator supply device), 23 ... mixing unit (mixing device, reaction accelerator supply device), 25 ... pressure sensor (pressure) Force meter, discharge device), 26 ... back pressure valve (pressure adjustment valve, discharge device), 27 ... back pressure regulator (BPR, pressure adjustment device), 28 ... separator (separator), 29 ... absorbance analysis Apparatus (VIS, concentration detection apparatus), 30 ... constant temperature bath (second temperature control apparatus), 31 ... hydrogen (H ₂ , reaction accelerator), 32 ... Cu (copper, metal used as a raw material for the conductor), 33 ... Cu thin film (conductor), 34 ... Tubular path (reaction suppression part) formed in a spiral shape, 35 ... Mantle heater (third temperature control device), 35a ... Upper mantle heater (third temperature control device) , 35b ... lower mantle heater (third temperature regulating device), 41 ... silicon layer (silicon substrate main body), 42 ... SiO ₂ film (silicon dioxide film, an insulating film provided above the substrate body), 42a ... first 1st interlayer insulation film (substrate Insulating film provided above the main body), 42b... Interlayer insulating film on the lower side of the second layer (insulating film provided above the substrate body), 42c... Interlayer insulating film on the upper layer side of the second layer ( Insulating film provided above the substrate body), 42d ... Interlayer insulating film (insulating film provided above the substrate body), 43 ... TiN thin film (separate from the conductor forming the inner surface of the recess) Other conductors), 44... Au thin film (other conductors separate from the conductor forming the inner surface of the recess), 51... Ru thin film (ruthenium thin film, conductor), 61... P well (Surface layer portion of substrate body), 62... Trench (recessed portion for providing a conductor formed on the substrate body), 67... Plate electrode (Ru thin film, trench capacitor embedded electrode), 68. (Insulation provided above the board body ), 73, 90, 96, 98... Semiconductor device, 82, 85, 88, 93... Barrier metal film (another conductor different from the conductor forming the inner surface of the recess), 84, 92. Via holes (recesses for providing a conductor formed in an insulating film provided above the substrate body), 86, 94... Via plugs (conductors), 87, 91... Upper layer wiring formation recesses (above the substrate body) (Recesses for providing a conductor formed in the provided insulating film), 89, 95... Upper layer Cu wiring, 97... Cu thin film (conductor), 97a... First wiring (Cu thin film, conductor), 97b. 2 wiring (Cu thin film, conductor), 97c ... 3rd wiring (Cu thin film, conductor), 97d ... 4th wiring (Cu thin film, conductor), 102 ... Preheating device (preheating system, preheating unit) ), 103 ... Preheating chamber (Purihi DOO chamber), 104 ... mantle heater (fourth temperature regulating device), 104a ... upper mantle heater (fourth temperature regulating device), 104b ... lower mantle heater (fourth temperature regulation device)

Claims (55)

An object to be processed in which at least one concave portion provided with a conductor is formed on the surface is accommodated in the inside, and a supercritical fluid in which a metal compound containing a metal that is a raw material of the conductor is dissolved is supplied to the inside. A reaction vessel in which a process of providing the conductor in the recess is performed;
A supply device for supplying the supercritical fluid from the outside to the inside of the reaction vessel;
A discharge device for discharging the supercritical fluid not subjected to the process from the inside of the reaction vessel to the outside;
And continuously supplying the supercritical fluid to the inside of the reaction vessel by the supply device and continuously supplying the supercritical fluid not subjected to the process by the discharge device to the outside of the reaction vessel. While adjusting the amount of the supercritical fluid in the reaction vessel by discharging, the metal compound dissolved in the supercritical fluid is brought into contact with the surface of the object to be treated and introduced into the recess, The metal compound introduced into the recess is aggregated in the recess to precipitate the metal from the metal compound, and the metal deposited in the recess is solidified to provide the conductor in the recess. An electrical conductor forming apparatus.   By adjusting the supply amount of the supercritical fluid to the inside of the reaction vessel by the supply device and the discharge amount of the supercritical fluid from the inside of the reaction vessel by the discharge device, the supercritical fluid in the reaction vessel is adjusted. 2. The conductor forming apparatus according to claim 1, wherein the amount of the critical fluid is stabilized.   The metal in the reaction vessel is adjusted by adjusting the supply amount of the supercritical fluid to the inside of the reaction vessel by the supply device and the discharge amount of the supercritical fluid from the inside of the reaction vessel by the discharge device. 3. The conductor forming apparatus according to claim 1, wherein the concentration of the compound is stabilized.   By adjusting the supply amount of the supercritical fluid to the inside of the reaction vessel by the supply device and the discharge amount of the supercritical fluid from the inside of the reaction vessel by the discharge device, the pressure in the reaction vessel is adjusted. It stabilizes, The formation apparatus of the conductor of any one of Claims 1-3 characterized by the above-mentioned.   The supply device includes a supercritical fluid supply device that supplies at least the raw material of the supercritical fluid toward the reaction vessel, and a raw material supply device that supplies the metal compound dissolved in the supercritical fluid. The conductor forming apparatus according to any one of claims 1 to 4, wherein the conductor is formed.   The supply device stops supply of the metal compound into the supercritical fluid by the raw material supply device while supplying the raw material of the supercritical fluid into the reaction vessel by the supercritical fluid supply device. The superconducting fluid in which the metal compound is not dissolved can be supplied into the reaction vessel instead of the supercritical fluid in which the metal compound is dissolved. Forming equipment.   The said supercritical fluid supply apparatus supplies the liquid carbon dioxide toward the said reaction container as a raw material of the said supercritical fluid, The formation apparatus of the conductor of Claim 5 or 6 characterized by the above-mentioned.   The said raw material supply apparatus melt | dissolves and supplies a solid organometallic complex as the said metal compound in the said supercritical fluid, The conductor of any one of Claims 5-7 characterized by the above-mentioned. Forming equipment.   The said raw material supply apparatus melt | dissolves and supplies the solid organometallic complex containing copper as the said solid organometallic complex in the said supercritical fluid, The formation apparatus of the conductor of Claim 8 characterized by the above-mentioned.   The said raw material supply apparatus dissolves and supplies diisobutyryl methanate copper in the said supercritical fluid as a solid organometallic complex containing the said copper, The formation apparatus of the conductor of Claim 9 characterized by the above-mentioned. .   The said raw material supply apparatus supplies the fluorine-free metal compound as the said metal compound in the said supercritical fluid, The formation apparatus of the conductor of any one of Claims 5-10 characterized by the above-mentioned.   The raw material supply device holds the solid metal compound dissolved in an auxiliary solvent that facilitates dissolution in the supercritical fluid, and the metal compound dissolved in the auxiliary solvent in the supercritical fluid. It supplies, The formation apparatus of the conductor of any one of Claims 5-11 characterized by the above-mentioned.   The raw material supply device holds the diisobutyrylmethanate copper dissolved in acetone as an auxiliary solvent as the solid metal compound and the diisobutyrylmethanate copper dissolved in the acetone as a supercritical fluid. The conductor forming apparatus according to claim 12, wherein the conductor is supplied into carbon dioxide in the form of a gas.   The said supply apparatus is further equipped with the reaction promoter supply apparatus which supplies the reaction promoter which accelerates | stimulates precipitation of the said metal from the said metal compound in the said supercritical fluid. The conductor forming apparatus according to any one of the above.   The reaction accelerator supply device is connected to the flow path upstream of the raw material supply apparatus in the supercritical fluid flow path from the supercritical fluid supply apparatus to the reaction vessel, and the raw material supply apparatus 15. The conductor forming apparatus according to claim 14, wherein the reaction accelerator is supplied into the supercritical fluid prior to supplying the metal compound into the supercritical fluid.   By adjusting the supply amount of the reaction accelerator into the supercritical fluid by the reaction accelerator supply device and the discharge amount of the supercritical fluid from the inside of the reaction vessel by the discharge device, The conductor forming apparatus according to claim 14, wherein the concentration of the reaction accelerator is stabilized.   The said reaction accelerator supply apparatus supplies hydrogen in the said supercritical fluid as said reaction accelerator, The formation apparatus of the conductor of any one of Claims 14-16 characterized by the above-mentioned.   18. A concentration detector for detecting a concentration of the metal compound dissolved in the supercritical fluid is further provided between the supply device and the reaction vessel. The conductor forming apparatus according to claim 1.   19. The conductor forming apparatus according to claim 18, wherein the concentration detection device is an absorbance analyzer.   The first temperature adjusting device for adjusting the internal temperature of the reaction vessel to a temperature at which the process can easily proceed is further provided outside the reaction vessel. The conductor forming apparatus according to any one of the above.   The flow path of the supercritical fluid from the connection between the supercritical fluid supply device and the reaction accelerator supply device to the reaction vessel is such that the temperature of the raw material of the supercritical fluid is the state of the supercritical fluid. The conductor forming apparatus according to any one of claims 5 to 20, wherein the conductor forming apparatus is provided inside a second temperature adjusting device that adjusts to a temperature that can be maintained.   The said 2nd temperature control apparatus is a thermostat which hold | maintains stably the internal temperature to the temperature which the raw material of the said supercritical fluid can exist in the state of a supercritical fluid. Conductor forming apparatus.   Between the supply device and the reaction vessel, a reaction in which the supercritical fluid in which the metal compound is dissolved is introduced into the reaction vessel while suppressing a reaction in which the metal compound is precipitated from the supercritical fluid. The conductor forming apparatus according to claim 1, further comprising a suppressing portion.   The third temperature adjusting device for adjusting the internal temperature of the reaction suppressing unit to a temperature at which the precipitation reaction is suppressed is further provided outside the reaction suppressing unit. The conductor forming apparatus according to 1.   A preheating device is further provided between the supply device and the reaction vessel to preheat the supercritical fluid to a predetermined temperature before introducing the supercritical fluid into the reaction vessel. The conductor forming apparatus according to any one of claims 1 to 24.   The preheating device includes a preheating chamber into which the supercritical fluid is introduced and a fourth temperature control device that heats the supercritical fluid introduced into the preheating chamber. 25. The conductor forming apparatus according to 25.   The discharge device includes a pressure adjusting device that sets a pressure of a flow channel downstream from the reaction vessel among flow channels of the supercritical fluid from the supply device to the discharge device to be lower than an internal pressure of the reaction vessel. 27. The conductor forming apparatus according to any one of claims 1 to 26, comprising: A supercritical fluid in which a metal compound containing a metal as a raw material for the conductor is dissolved is continuously supplied toward an object to be processed in which at least one recess is provided on the surface. By continuously excluding the supercritical fluid not subjected to the process of providing the conductor from the periphery of the object to be processed, the amount of the supercritical fluid around the object to be processed is adjusted,
The metal compound dissolved in the supercritical fluid is brought into contact with the surface of the object to be treated and selectively introduced into the recess, and the metal compound introduced into the recess is aggregated in the recess. And depositing the metal from the metal compound,
Providing the conductor in the recess by solidifying the metal deposited in the recess,
A method for forming a conductor.   The amount of the supercritical fluid around the object to be processed is stabilized by adjusting the supply amount of the supercritical fluid to the object to be processed and the amount of exclusion of the supercritical fluid from the periphery of the object to be processed. The method for forming a conductor according to claim 28, wherein:   By adjusting the supply amount of the supercritical fluid to the object to be processed and the amount of exclusion of the supercritical fluid from the periphery of the object to be processed, the concentration of the metal compound around the object to be processed is stabilized. 30. The method of forming a conductor according to claim 28 or 29.   Adjusting the supply amount of the supercritical fluid to the object to be processed and the amount of exclusion of the supercritical fluid from the periphery of the object to be processed, thereby stabilizing the pressure around the object to be processed; The method of forming a conductor according to any one of claims 28 to 30.   In place of the supercritical fluid in which the metal compound is dissolved, a supercritical fluid in which the metal compound is not dissolved is supplied toward the object to be processed, thereby reducing the concentration of the metal compound around the object to be processed. It adjusts, The formation method of the conductor of any one of Claims 28-31 characterized by the above-mentioned.   The method for forming a conductor according to any one of claims 28 to 32, wherein carbon dioxide is used as a raw material of the supercritical fluid.   34. The method of forming a conductor according to any one of claims 28 to 33, wherein a solid organometallic complex is supplied as the metal compound into the supercritical fluid.   35. The method of forming a conductor according to claim 34, wherein a solid organometallic complex containing copper is supplied into the supercritical fluid as the solid organometallic complex.   36. The method of forming a conductor according to claim 35, wherein diisobutyryl methanate copper is supplied into the supercritical fluid as a solid organometallic complex containing copper.   37. The method of forming a conductor according to any one of claims 28 to 36, wherein a fluorine-free metal compound is supplied as the metal compound into the supercritical fluid.   A solid metal compound is used as the metal compound, and the solid metal compound is dissolved in an auxiliary solvent that facilitates dissolution in the supercritical fluid, and then the solid metal compound dissolved in the auxiliary solvent is The method for forming a conductor according to any one of claims 28 to 37, wherein the conductor is supplied into a supercritical fluid.   Diisobutyryl methanate copper is used as the solid metal compound, and the diisobutyryl methanate copper is dissolved in acetone as a co-solvent, and then the diisobutyryl methanate copper dissolved in the acetone is used in excess. The method for forming a conductor according to claim 38, wherein the conductor is supplied into carbon dioxide in a critical fluid state.   40. The method of forming a conductor according to any one of claims 28 to 39, further comprising supplying a reaction accelerator for promoting precipitation of the metal from the metal compound into the supercritical fluid. .   41. The method of forming a conductor according to claim 40, wherein the metal accelerator is supplied into the supercritical fluid after the reaction accelerator is supplied into the supercritical fluid.   By adjusting the supply amount of the reaction accelerator into the supercritical fluid and the exclusion amount of the supercritical fluid from the periphery of the object to be processed, the concentration of the reaction accelerator around the object to be processed is adjusted. The method of forming a conductor according to claim 40 or 41, wherein the method is stabilized.   43. The method of forming a conductor according to any one of claims 40 to 42, wherein hydrogen is supplied into the supercritical fluid as the reaction accelerator.   44. The method of forming a conductor according to any one of claims 28 to 43, wherein the temperature of the object to be processed and its surroundings are adjusted to a temperature at which the process can easily proceed.   45. The method according to claim 28, wherein the temperature of the raw material of the supercritical fluid is adjusted toward a temperature at which the raw material can exist in a supercritical fluid state, and is supplied toward the object to be processed. The method for forming a conductor according to item.   46. The reaction of precipitating the metal compound from the supercritical fluid is suppressed until the supercritical fluid reaches the periphery of the object to be processed. The method for forming a conductor according to item.   The method of forming a conductor according to claim 46, wherein the temperature of the supercritical fluid is adjusted to a temperature at which the precipitation reaction is suppressed until the supercritical fluid reaches the periphery of the object to be processed. .   The method for forming a conductor according to any one of claims 28 to 47, wherein the supercritical fluid is heated to a predetermined temperature in advance before the supercritical fluid is introduced into the reaction vessel.   49. The method of forming a conductor according to claim 48, wherein the predetermined temperature is set to be equal to or lower than a processing temperature when the conductor is provided in the recess inside the reaction vessel.   The conductive material according to any one of claims 28 to 49, wherein the object to be processed is disposed inside the reaction container in a posture in which a surface on which the concave portion is formed is directed downward. Body formation method.   In the flow of the supercritical fluid flowing around the object to be processed, the pressure on the downstream side of the object to be processed is made smaller than the pressure on the upstream side of the object to be processed. 51. The method for forming a conductor according to claim 28, wherein the supercritical fluid is excluded from the surroundings.   52. The conductor according to any one of claims 28 to 51, wherein the conductors are collectively provided in the plurality of recesses having at least one of shape, depth, width, and aspect ratio different from each other. The method for forming a conductor according to item. A metal including a metal that is a raw material of the conductor toward a semiconductor substrate in which at least one concave portion in which a conductor is provided is formed on at least one surface of the substrate body and an insulating film provided above the substrate body By continuously supplying a supercritical fluid in which a compound is dissolved, and continuously excluding the supercritical fluid not subjected to the process of providing the conductor in the recess from the periphery of the semiconductor substrate, the semiconductor substrate Adjusting the amount of the supercritical fluid around
The metal compound dissolved in the supercritical fluid is brought into contact with the surface of the semiconductor substrate and selectively introduced into the recess, and the metal compound introduced into the recess is aggregated in the recess. Depositing the metal from the metal compound;
Providing the conductor in the recess by solidifying the metal deposited in the recess,
A method for manufacturing a semiconductor device.   54. The manufacturing method of a semiconductor device according to claim 53, wherein the conductor is provided in the recess formed in a surface layer portion of the substrate body to form a buried electrode of a trench capacitor in the surface layer portion of the substrate body. Method.   54. The semiconductor device according to claim 53, wherein at least one of a wiring and a plug is formed in the insulating film by providing the conductor in the recess formed in the insulating film provided above the substrate body. 54. A method of manufacturing a semiconductor device according to 54.

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