JP2010056565A - Apparatus for forming thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for forming a thin film excellent in productivity and mass productivity capable of stably achieving long-term continuous film formation with a reduced number of particles, while favorably reproducing a film-thickness distribution, a composition distribution and a film-formation rate. <P>SOLUTION: The thin-film manufacturing apparatus is a CVD device configured to introduce a film forming gas into a reaction chamber through a shower head from a top of a reaction chamber that is a reaction space and form a film on a heat substrate. An upper reaction space is formed of a substrate stage that is neither rotated nor lifted, a shower head and a contamination shield in which a concentric gap is formed between the contamination shield and the substrate stage to serve as a gas-exhausting passage, so that an inert gas can flow along the contamination shield from an upper portion of the gas-exhausting passage. A lower space is formed at a secondary side of the gas-exhausting passage. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a thin film production equipment.

  In a conventional thin film manufacturing apparatus, in the case of an apparatus equipped with a substrate stage lifting mechanism, a concentric exhaust port (exhaust path) adjusted in the atmosphere when the substrate stage is pulled into the vacuum during vacuum to play the lifting mechanism. Is out of balance. Therefore, in order to achieve a uniform film thickness distribution on the substrate, an exhaust port of 5 mm or more on one side is required if the film thickness distribution is within ± 3%, and 10 mm or more is required if it is within ± 2% ( For example, see Patent Document 1.) In addition, in an apparatus equipped with this substrate stage elevating mechanism, in order to raise the substrate stage from the substrate transfer position to the film forming position, it is necessary to have a structure in which a large space (for example, 13 L) is provided below the substrate stage during film formation. There wasn't. This lower space is a space for realizing isotropic exhaust, but because of the play of the lifting mechanism, the substrate stage is pulled in the vacuum during vacuum, and the concentric exhaust outlet balance adjusted in the atmosphere is lost. It needed more volume than necessary.

  Conventionally, an apparatus provided with a deposition preventing plate is also known in order to prevent film formation on the inner wall of the vacuum chamber. Such an apparatus has a deposition plate raising / lowering mechanism that raises the deposition plate during film formation and lowers the deposition plate during substrate transfer. Film formation occurred on the inner side of the adhesion-preventing plate constituting the space, becoming a generation source of particles, and shortening the maintenance cycle of the mass production apparatus.

  In the case of an apparatus equipped with this deposition preventive plate, the film forming gas also circulates to the outside of the deposition preventive plate, and film formation occurs little by little on the inner wall of the vacuum chamber. In addition, film formation occurs directly on the inner wall of the vacuum chamber. When the film formed on the inner wall of the vacuum chamber has a certain thickness, the film is peeled off and causes generation of particles.

  In the conventional thin film manufacturing apparatus, when the temperature control of the shower head for introducing the film forming gas into the reaction vessel is performed, it is necessary to adjust the distance between the shower head and the substrate according to the type of the substrate and the raw material. is there. However, since the shower nozzle is used as an operating part (see, for example, Patent Document 2), an unnecessary space in which convection and turbulence are generated around the shower head is provided, which becomes a generation source of particles, and the maintenance cycle of the mass production apparatus is reduced. It is shortened.

  Moreover, in the thin film manufacturing apparatus performing such temperature control, generally, the distance between the surface of the shower head (shower plate) and the substrate is set to 40 mm or less, and the shower head surface is extremely heated by radiation. The method of cooling the shower head by oil circulation is used. However, a structure for sufficiently releasing the heat of the showerhead surface, that is, a structure for sufficiently exchanging heat is not considered, and the temperature of the circulating oil needs to be extremely lowered. In addition, in this case, even if the temperature of the showerhead surface becomes the optimum temperature, the portion other than the showerhead surface becomes low temperature, the raw material is precipitated, and particles are generated.

  In an apparatus that performs the above temperature control, since the strength of aluminum (Al) begins to drop extremely in an environment where the temperature of the heating medium exceeds 120 ° C., the material of the heating medium path must be SUS for safety. Currently. As is well known, SUS has poor thermal conductivity (thermal conductivity: about 240 W / mK for SUS, about 240 W / mK for SUS), and heat transfer is slow. Therefore, in the case of a shower head structure in which the parts of the heating medium path are made of SUS, if the shower head surface is a separate plate-like part, in order to efficiently exchange the heat of the plate, heat exchange between the plate and the heating medium path part A structure in which the area is sufficiently large and the heating medium path is in the vicinity of the plate contact surface is required.

Furthermore, the conventional thin film manufacturing apparatus uses quartz or alumina excellent in heat resistance for the substrate stage member that contacts the heat source. However, since alumina has difficulty in thermal shock characteristics, the occurrence of cracks and the frequency of breakage increase due to the raising and lowering of each substrate, and quartz loses O ₂ in a high temperature reduction reaction atmosphere, and the quartz is lost. Deteriorating and changing the film forming environment of the substrate. These also serve as a generation source of particles. As a result, there is a problem that the maintenance cycle of the apparatus is shortened and stable film formation cannot be performed over a long period of time.

  Furthermore, when venting the inside of an apparatus in a conventional thin film manufacturing apparatus, since the vent is made upward from the lower space, particles generated during film formation occur during the venting and react each time the vent is vented. We needed to clean the room. For example, as described in Japanese Patent Application No. 2003-61391, which is a prior application filed by the present applicant, the number of particles measured on the substrate increases even when the gas is stopped between the substrate processing lots. Therefore, there is a need for a system that can vent the downflow without stopping the gas from the downflow state of the apparatus.

In the conventional apparatus described above, turbulent flow, convection, and thermal convection are not particularly considered with respect to the gas flow, and the film is likely to be peeled off and particles are generated during film formation.
As described above, when cleaning the film formed on the inner wall of the vacuum chamber, etc., if the film cannot be removed efficiently by reaction treatment with plasma or chemical gas, the worker directly removes it using chemicals such as nitric acid. It must be done and is dangerous. Alternatively, as another cleaning method, there is a case where a large-scale operation of removing the vacuum chamber and sending it to a cleaning maker and cleaning there may occur. Therefore, it can be said that such a thin film manufacturing apparatus is not practical as a mass production apparatus on the premise that it can be used safely and efficiently.

WO 03/048413 A1 (19 pages, FIG. 8) JP-A-9-316644 (Claims, Examples)

An object of the present invention is to solve the problems of the prior art, when the vent film forming chamber, wound up not occur deposits, provides a thin film production equipment capable of suppressing the Shisan There is.

The thin film manufacturing apparatus of the present invention includes a film forming tank having an open top, a lid portion that closes the opening, a film forming gas line connected to the lid portion, and a film forming gas through the film forming gas line. A shower plate that is attached to the back surface of the lid portion to define a predetermined space so that the film forming gas is diffused when supplied, and a substrate stage that is disposed opposite to the shower plate in the film forming tank; A gas exhaust path provided around the substrate stage and capable of isotropic exhaust, and the film forming gas introduced into the film forming chamber through the gas passage portion of the shower plate facing the space is The thin film manufacturing apparatus configured to be guided to a gas exhaust path further includes a vent gas line communicating with the space, and the vent gas can be supplied to the space through the vent gas line, and the substrate stay Than the contour of the projection surface to above the substrate mounting portion, wherein said a gas passage portion is formed inwardly.

In the present invention, the film forming gas line and the vent gas line may be combined.

In the present invention, a slow vent system may be provided in the vent gas line. As a result, the initial venting speed can be reduced so that particles are not generated.

In the present invention, a heating medium circulation path may be formed inside the lid so as to cover the upper side from the side of the space.

The width of the gas exhaust path is desirably 3 mm or more and 15 mm or less. If the thickness is less than 3 mm, a stable film thickness distribution cannot be obtained, and if it exceeds 15 mm, the film formation rate becomes slow, which is not practical.

Distance between the substrate placed on the surface and the substrate stage of the shower plate 10 to 70 mm, and it is preferably Ru is configured to be 10Mm～40mm. Effect of shower holes is less than 10mm appear on the wafer surface (thickening immediately below the shower holes) exceeds 70 mm, thereby giving space to produce a turbulent flow and heat convection.

Substrate stage provided in a thin film manufacturing apparatus of the present invention, the substrate mounting portion of the surface is produced from a material with high thermal conductivity, thermal conductivity than part component substrate stage member mounting substrate in contact with the substrate mounting portion It may be made of a poor material.

According to the thin film production equipment of the present invention, rather than the vent from the deposition tank bottom, because the vent-down flow from the substrate stage above the shower head is made not occur hoisting deposits, inhibit Shisan be able to.

The schematic sectional drawing which shows the apparatus structure of the thin film manufacturing apparatus of this invention. FIG. 2A is a diagram illustrating an arrangement relationship of the components in FIG. 1, and FIG. 2A is a top view illustrating an arrangement relationship of a substrate stage, a stage cover, a gas exhaust path, and a deposition preventing plate, and FIG. Figure. The circuit diagram which shows a general gas source. The circuit diagram which shows the gas source which is one embodiment of this invention. The circuit diagram which shows the gas path | route which is one embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows one Embodiment of the apparatus of this invention, (A) is sectional drawing of the upper part of a vacuum chamber, (B) is the top view of the whole which cut | disconnected the upper part of the vacuum chamber in the predetermined position, And (C) is a top view of the center part which cut | disconnected the upper part of the vacuum chamber in the predetermined position. The graph which shows the relationship between exhaust clearance and film thickness distribution. The graph which shows the relationship between exhaust clearance and the film-forming rate of a substrate center. The graph which shows the relationship of the center temperature of the shower plate with respect to board | substrate temperature. The graph which shows the relationship between shower plate-substrate distance and shower plate center temperature. The graph which shows the temperature distribution of a shower plate. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows one embodiment of this invention, (A) is a schematic sectional drawing which shows arrangement | positioning with a vacuum tank upper cover and a shower plate, (B) is the top view.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing a configuration of a vacuum chamber which is a main part of a thin film manufacturing apparatus according to the present invention.

  A vacuum chamber 1 shown in FIG. 1 has a shower head 3 incorporated in an upper lid 2, and a substrate stage 4 is installed below the shower head 3. The substrate stage 4 is configured to be fixed so as not to rotate or move up and down. However, it may be liftable. A substrate stage cover 5 is preferably attached to the outer peripheral side wall of the substrate stage 4. In the vicinity of the side wall of the substrate stage 4, a deposition plate 6 is arranged with a predetermined interval. The deposition plate is raised by a deposition plate lifter 6a, which is a lifting mechanism, and lowered when the substrate is transported. It is attached so that it can be raised and lowered. The reaction space A at the time of film formation is constituted by such a shower head 3, the substrate stage 4, and the deposition preventing plate 6. A gap formed by the deposition preventing plate 6 and the substrate stage 4 forms a concentric gas exhaust path 7. In this vacuum chamber 1, an inert gas is introduced into the vacuum chamber through an opening 8 provided on the outer periphery of the upper lid 2, and a deposition plate is provided from the upstream side of the gas exhaust path 7 through an inert gas jet port 9. 6 is a structure that flows downstream along the inner wall surface. Thus, the lower space B having a volume larger than that of the reaction space A is directly connected to the gas exhaust path 7 constituted by the deposition preventing plate 6 and the substrate stage 4, and isotropic exhaust is realized. Has been. The pressure control in the vacuum chamber at the time of film formation is configured such that the pressure is fed back from the pressure measuring device 10 attached to the upper lid 2 to the pressure adjusting valve 11, and the pressure can be selected according to the process. .

  Further, a vacuum exhaust system 12 is connected to the vacuum chamber 1 via a valve 12a so that the pressure in the vacuum chamber can be controlled. Further, between the film forming gas inlet provided in the upper part of the vacuum chamber and the shower head 3, there is a space where the introduced gas spreads and functions as a reaction space. Further, although not shown in the figure, the vacuum chamber 1 is provided with a mixer connected to be separated by a film forming gas pipe in order to supply a film forming gas to the shower head 3 incorporated in the upper lid 2. A vaporization system (vaporizer) connected to the mixer by a raw material gas pipe is provided. In order to keep the vaporized source gas at a temperature at which the vaporized source gas is not liquefied / deposited / formed into a film, such as gas piping from the vaporization system to the vacuum chamber, various valves, mixers, etc., heating means such as a heater or heat exchange A vessel is provided. The piping between the vaporization system and the mixer is provided with a valve V3, and the piping between the vaporization system and the exhaust system is provided with a valve V4, as will be described in detail below with reference to FIG. Thus, the vaporization system, the mixer, and the exhaust system can be shut off. The purpose of this is to prevent substances such as moisture that adversely affect film formation from being released to the atmosphere because the maintenance cycles of the components of the vaporization system, mixer and exhaust system are different. To do. When maintenance is performed with one component open to the atmosphere, the vacuum can be maintained without releasing the other two components to the atmosphere.

  Using the apparatus shown in FIG. 1, a thin film can be manufactured as follows. A film forming gas (a raw material gas used for a chemical reaction, a reaction gas, a mixed gas composed of an inert gas used for controlling partial pressure in the vacuum chamber, or each gas) is introduced from the upper part of the upper lid 2 of the vacuum chamber 1 through its inlet. Then, a film forming gas is sprayed onto the substrate placed on the substrate stage 4 from the shower head 3 to form a film. Excess film forming gas, by-products and the like are isotropically exhausted out of the tank through the gas exhaust path 7. At the time of film formation, an inert gas is introduced into the vacuum chamber 1 through an opening 8 provided on the outer periphery of the upper lid 2, and the protective plate 6 is formed from the upstream side of the exhaust path 7 through an inert gas jet port 9. Flow along the inner wall. Since the lower space B having a volume larger than that of the reaction space A is provided directly connected to the gas exhaust path 7 constituted by the deposition preventing plate 6 and the substrate stage 4, isotropic exhaust is realized. Yes.

  2A is a top view showing the arrangement relationship of the substrate stage, the substrate stage cover, the gas exhaust path, and the deposition preventing plate constituting the vacuum chamber shown in FIG. 1, and FIG. 2B is a sectional view thereof. is there. As shown in FIGS. 2A and 2B, a substrate stage cover 5 is provided on the outer periphery of the substrate stage 4, and a gas exhaust path 7 and a deposition plate 6 are provided on the outer periphery thereof. And the substrate stage are configured such that the size (width) thereof is r. Further, as shown in FIG. 2B, the length of the gas exhaust path in the vertical direction is L.

A gas source (a raw material gas source, a reactive gas source, an inert gas source, etc.) capable of controlling the gas flow rate as shown in FIG. 3 is connected to the primary side of the film forming gas introduction port. Are configured so that a plurality of gases can be discharged from one gas source.
FIG. 4 shows an example of the integrated gas source. The gas source A and the gas source B are connected to lines according to their respective needs. That is, the gas sources A and B are connected to the reaction gas line and the inert gas line via valves and mass flow controllers (MFC1, MFC2, and MFC3), respectively. Further, a vent gas line is connected to the line of the gas source B via a vent V, and the vent V may be a slow vent V.

  In the present invention, the gas path system shown in FIG. 5 is installed between the gas source (FIG. 4) and the film forming gas inlet (FIG. 1). In this system, when a film forming process is performed, a raw material gas source that vaporizes (liquid) raw material by a vaporization system to form a raw material gas and a reactive gas (inert gas and reactive gas) necessary for the process. A gas mixed at an appropriate ratio (hereinafter, abbreviated as “reactive gas”) is supplied from a gas source A to which the respective gases are supplied into the mixer, where they are mixed uniformly. Has been. This mixer has a structure in which a raw material gas and a reaction gas are introduced to face each other, and are uniformly mixed by stirring and diffusing to obtain a film forming gas (Japanese Patent Application No. 13-1990). 369279). This film forming gas is introduced into the reaction tank 1 of FIG. 1 through the film forming gas inlet by opening the valve V 1, and reaches the substrate through the shower head 3. The inert reaction gas is introduced into the tank from the gas source B through the opening 8 on the outer periphery of the upper lid 2 of the vacuum tank 1 by opening the valve V6. Similarly, in the case of venting in a vacuum chamber, vent gas is introduced into the chamber from the film forming gas inlet through the shower head 3 by opening the vent V such as the slow vent V and the valve V5. In addition, all the gas paths (including the mixer) from the heat exchanger in FIG. 5 to the primary side (including the mixer) can be controlled from room temperature to 250 ° C. by heating means such as a heater or heat exchange. Temperature control means such as a vessel is provided. Similarly, all the pipes exiting from the source gas source are provided with the same temperature control means that enables temperature control from room temperature to 250 ° C.

Next, the operation of the gas path shown in FIG. 5 will be described in detail. The mixer is connected to the vaporization system by a pipe provided with a valve V3, and is connected to a gas source (for example, a reactive gas source, a non-reactor) via a valve V5, a heat exchanger, and then a mass flow controller (not shown). It is also connected to an active gas source. The film-forming gas uniformly mixed in the mixer is transferred to the film-forming gas inlet through the pipe provided with the valve V1, and is formed on the substrate stage in the vacuum chamber. Is supplied to the surface of the substrate. In addition to the reaction gas source, an inert gas (for example, N ₂ ) supply system is connected to the reaction gas source, and each supply system is controlled by adjusting a valve element. The gas is transported from the gas source to the mixer through a mass flow controller and a heat exchanger. Examples of the reaction gas include a gas suitable for a raw material gas for producing a target film, for example, H _{2 in} the reduction reaction, NH _{3 in the} nitridation reaction, O _{2 in the} oxidation reaction, and the like. is there. The source gas is a gas obtained by vaporizing a source solution obtained by dissolving an organometallic compound or the like in an organic solvent.

  In the mixer, the appropriately heated reaction gas supplied from the reaction gas source and the raw material gas that is generated by the vaporization system and sent through a pipe maintained at a temperature at which no liquefaction / deposition / film formation is introduced and mixed are introduced and mixed. A film forming gas (reaction gas + raw material gas, etc.) is obtained. This source gas is a gas in which one kind or a plurality of kinds of gases are mixed. The film forming gas thus obtained is introduced into the vacuum chamber through a pipe.

  The pipe between the vaporization system and the mixer and the pipe between the mixer and the film forming gas inlet may be connected by a VCR joint, and the VCR gasket of some of the pipe joints is a simple ring. Instead, it may be a VCR type particle trap where the hole is a particle trap. The joint with this VCR type particle trap is set and maintained at a temperature higher than the temperature at which the source gas is not liquefied / deposited, and does not attach or trap the specific vaporized source elements necessary for the reaction. desirable.

  Valves (V1 and V2) for switching the film forming gas are provided on the secondary side of the mixer 5 in the film forming gas line between the mixer and the vacuum chamber. The downstream sides of the valves V1 and V2 are connected to a vacuum chamber and an exhaust system, respectively. During film formation, valve V1 is opened and valve V2 is closed, and after film formation is completed, valve V2 is opened and valve V1 is closed. During the initial few moments when the raw material gas or the reactive gas is introduced into the mixer, the mixing is not uniform and unstable. Therefore, the valve V1 is closed and the valve V2 is opened, and the mixed gas of the raw material gas and the reactive gas is supplied to the exhaust system. After the mixing is stabilized, the valve V2 is closed and the valve V1 is opened so that the film forming gas can be introduced into the reaction space through the shower head. At the end of film formation, the valve V2 is opened for a moment and the valve V1 is closed, and excess film formation gas that has not been used for the reaction in the mixer is caused to flow to the exhaust system, thereby forming the film formation gas into the reaction space. Is stopped instantaneously and is not introduced into the reaction space.

  Although not shown, the vaporization system includes a raw material supply unit and a vaporization unit. This vaporization system pressurizes and conveys a raw material liquid obtained by dissolving a liquid / solid raw material in an organic solvent with a pressurized gas (for example, an inert gas such as He gas), and sets the flow rate of each of the pumped raw material liquids. It is configured to be controlled by a liquid flow rate controller and carried to the vaporization section. The vaporization unit is configured to efficiently vaporize the raw material liquid whose flow rate is controlled and supply the raw material gas obtained by vaporization to the mixer. In this vaporization section, when there is only one liquid raw material, a single liquid can be mixed, and when there are a plurality of liquid raw materials, a plurality of raw material liquids can be mixed and vaporized. When vaporizing the raw material liquid, not only vaporize the liquid droplets of the raw material liquid, but also apply gas to the liquid droplets, apply physical vibrations, or apply ultrasonic waves to the vaporization part wall surface. It is preferable to introduce vaporization into the vaporization part as finer liquid particles through the nozzle and vaporize it to increase the vaporization efficiency. Inside the vaporization section, heat or liquid such as Al is used so that droplets or liquid particles can be vaporized as much as possible at the place where vaporization should be efficiently performed, and in order to reduce the liquid vaporization load by the particle trap. It is preferable to arrange a vaporizing member made of a material having good conductivity. In addition, inside the vaporization unit, particles based on the residue generated when the raw material liquid is vaporized are not discharged out of the vaporization unit, and a small amount of liquid droplets are not sucked out of the vaporizer by vacuum. In order to be able to vaporize, a particle trap may be provided. In this vaporization member and particle trap, appropriate droplets and fine liquid particles that are in contact with these vaporizers can be properly vaporized, and appropriate vaporizer elements that are necessary for the reaction are not attached or captured. It is preferable that vaporization conditions are maintained at the temperature. This vaporization system has a raw material solvent, and is configured so that the flow rate is controlled by a flow rate controller, introduced into the vaporization unit, and vaporized by the vaporization unit to produce the solvent gas. It may be.

A film forming gas is introduced onto the heated substrate, which is a film forming target, via the shower head 3 and the reaction is started. However, due to an excess film forming gas that has not been used for the reaction or due to the reaction, The produced by-product gas and reactant gas are exhausted by the exhaust system. The shower head 3 incorporated in the upper lid 2 of the vacuum chamber 1 may be provided with a particle trap as a filter for capturing particles present in the film forming gas. The shower head 3 is appropriately heated and maintained at a temperature at which the introduced gas does not liquefy / deposit / film-form. Further, it is desirable that the particle trap is appropriately adjusted to a temperature at which a specific vaporized raw material element necessary for the reaction is not attached and trapped.
Various film forming pressure conditions can be easily accommodated by the pressure adjusting valve provided between the exhaust system and the vacuum chamber.

  In the thin film manufacturing apparatus of the present invention, the distance between the surface of the shower plate and the substrate is fixed, and is configured to be the same distance during film formation and transport, but by selecting a spacer at the stage of assembling the substrate stage. Further, a structure that can be selected from three types of arbitrary distances, for example, 10 mm, 25 mm, and 40 mm, can be used.

  Next, the vacuum tank upper lid and the shower plate in the thin film manufacturing apparatus of the present invention will be described with reference to FIG. In FIG. 6, the same components as those in FIG. 1 are denoted by the same reference numerals. 6A shows a cross-sectional view of the upper portion of the vacuum chamber 1, FIG. 6B shows an overall top view of the upper portion of the vacuum chamber cut at a predetermined position, and FIG. The top view of the center part which cut the upper part of the vacuum chamber in the predetermined position is shown.

As shown in FIG. 6, a shower head structure including a portion 13 where gas spreads may be incorporated in the upper lid 2, and the upper lid 2 and the shower head 3 may be integrated. The size of the shower plate 3 is designed to be approximately the same as the area of the ceiling portion of the vacuum chamber 1. By adopting such a structure, as shown in FIG. 6, a large area (contact area) in which the shower plate 3 exchanges heat is secured, and heat exchange can be performed efficiently.
The area of the shower plate 3 is configured to be larger than the ceiling area of the reaction space A surrounded by the shower plate 3, the substrate stage 4 and the deposition preventing plate 5 as shown in FIG. The reaction space (that is, the area where the shower plate receives radiation) is made small, while the area for heat exchange of the shower plate 3 is sufficiently secured.

  The upper lid 2 is made of SUS, and is configured such that temperature control can be performed by an oil circulation path 14 from oil-in to oil-out as shown in FIG. The oil circulation path 14 is configured to sit down in a wide range inside the upper lid, and the screw hole 3a for stopping the shower plate 3 exists in an island shape inside the area filled with oil, so that the oil circulation path becomes wider. Therefore, the temperature of the upper lid 2 can be made uniform and the temperature controllability is improved. Further, most of the oil circulation path 14 is arranged in contact with the surface of the shower plate 3 incorporated in the upper lid 2 so that the heat exchange efficiency can be improved. Therefore, in particular, a structure capable of realizing excellent heat exchange efficiency that can be handled even in an environment where the substrate temperature during film formation is high, the distance between the shower plate and the substrate is short, and the shower plate 3 is heated by intense radiation. It has become. The medium used in this circulation path is not particularly limited as long as it is not oil but is a medium such as a known warm medium having the same action.

The shower plate 3 has a concave shape when viewed from the side, and the gas passage portion preferably has a thickness (generally about 5 mm) that optimizes the conductance of the shower hole.
The heat exchange part of the shower plate 3 and the upper lid 2 is designed to be thick (for example, about 10 mm) for the purpose of increasing the temperature uniformity of the shower plate heat exchange part. The heat exchange efficiency is increased by exchanging heat after spreading.

Hereinafter, standard film formation conditions for producing a PZT film by the MOCVD method are listed, and film formation was performed under these conditions using the apparatus of the present invention.
(Raw material) (Concentration) (Set flow rate)
Pb (dpm) ₂ / THF 0.3mol / L 1.16mL / min
Zr (dmhd) ₄ / THF 0.3mol / L 0.57mL / min
Ti (iPrO) ₂ (dpm) ₂ / THF 0.3mol / L 0.65mL / min
N ₂ (carrier gas) 500sccm
(Reactive gas)
O ₂ 2500sccm
(Inert gas around the gas head)
N ₂ 1500sccm
Film forming pressure: always adjusted to 5 Torr constant by the pressure adjusting valve.
Substrate temperature: 580 ° C
Shower plate-substrate distance: 30 mm

  Using the thin film manufacturing apparatus shown in FIG. 1, on the 8-inch electrode substrate placed on the substrate stage 4, the size of the gas exhaust path 7, that is, the exhaust clearance (r: 3 to 20 mm) and the vertical length ( L: 30, 50, 70, and 90 mm) were changed, and a PZT film was manufactured under the above film forming conditions. The film thickness distribution (%) obtained as a result is shown in FIG. 7 in relation to the exhaust clearance. As is apparent from FIG. 7, by setting the exhaust path size (r) = 3 mm or more and the vertical length (L) 70 mm or more, a good film thickness distribution of 3% or less in the plane can be stably achieved. Obtainable.

  Further, a PZT film was manufactured on the 8-inch electrode substrate under the above film forming conditions by changing the gas exhaust path, that is, the size (r) of the exhaust clearance and the vertical length (L). FIG. 8 shows the relationship between the exhaust clearance and the film formation rate at this time. Since the film thickness distribution varies depending on the conditions, the film formation rate at the center of the substrate is obtained and compared. In a mass production apparatus, the film formation time is desirably 3 min or less in consideration of the throughput. For example, when the target film thickness is 100 nm, a film forming rate of about 35 nm / min or more is required. As is apparent from FIG. 8, the condition for satisfying this film formation rate is that the size (r) of the exhaust path is 3 to 15 mm when the length in the vertical direction (L) is 70 mm or more.

  6 are designed such that R1 = 200 mm, R2 = 370 mm, and R3 = 390 mm, the dimensions of the space (reaction space) in which the gas spreads, the size of the shower plate, and the size of the ceiling of the vacuum chamber. The shower plate 3 has a diameter (R2) that can utilize almost the entire area of the upper lid 2 except the outer peripheral inert gas jet outlet as a heat exchange area. Thereby, the heat exchange area (φR2-φR1) of the upper lid and the shower plate is secured about 2.4 times that of the gas passage portion (φR1 = no heat exchange between the shower plate and the upper lid).

  Further, in the apparatus configuration shown in FIG. 1, a change in the center temperature of the shower plate was confirmed when the substrate temperature was changed without controlling the temperature of the upper lid at a shower plate-substrate distance of 40 mm. The result is shown in FIG. The reaction space is controlled to an inert gas atmosphere of 5 Torr. Among the materials shown in the standard film formation conditions, the raw material is deposited at 200 ° C. or lower and decomposes at 250 ° C. or higher. Therefore, the location where the raw material gas contacts is controlled within the range of 200 ° C. to 250 ° C. There is a need. In the apparatus structure shown in FIG. 1 that suppresses turbulent flow, convection, and thermal convection, as shown in FIG. 9, the temperature of the shower plate facing the substrate at a short distance increases, so the temperature control of the shower plate is essential. It is an item.

  Further, in the apparatus structure shown in FIG. 1, the change in shower plate center temperature when the distance between the shower plate and the substrate is changed under the condition that the inert gas atmosphere, the pressure is 5 Torr, the substrate temperature is 580 ° C., and the temperature of the upper lid is not controlled. confirmed. The result is shown in FIG. As apparent from FIG. 10, the influence of the shower plate-substrate distance on the shower plate temperature is much slower than the substrate temperature. However, if the shower plate-substrate distance is shortened, the shower plate temperature increases ( The temperature rises by about 16 ° C. with a change from 40 mm to 10 mm).

  Next, oil at 215 ° C. was circulated at a rate of 5 L / min or more through the upper lid of the vacuum chamber having the structure shown in FIG. When the inert gas atmosphere, the pressure was 5 Torr, the substrate temperature was 580 ° C., and the distance between the shower plate and the substrate was 40 mm, the shower plate center temperature was 232 ° C., which was about 160 ° C. lower than before the oil circulation. FIG. 11 shows the temperature distribution in the radial direction from the center of the shower plate at this time. As is apparent from FIG. 11, the temperature distribution of the shower plate is in the range of ± 10 ° C., and the range in which the shower plate temperature passes through the film forming gas that most affects the film formation is φ200 mm (from the center). The temperature distribution with a radius of 100 mm was as good as about ± 5 ° C. Furthermore, the oil circulation temperature was 215 ° C., the upper lid temperature was maintained at 210 ° C. or higher, and no raw material was deposited in the space where the film formation gas for the upper lid was introduced.

  Further, in the structure of FIG. 6, when the distance between the shower plate and the substrate is 10 mm, as shown in FIG. 10, the temperature rise of the highest temperature portion (shower plate center point) on the surface of the shower plate is 16.2 ° C. or less at the maximum. Met. Therefore, even when the distance between the shower plate and the substrate is 10 mm, the shower plate can be maintained in the temperature range of 200 to 250 ° C. Furthermore, the shower plate can be adjusted to the optimum temperature by selecting the circulating oil temperature.

The tightening torque of the shower plate fixing screw (M6 × 24 pieces) 3a shown in FIG. 6 is 5 N · m, and the axial force W of one screw is given by the following equation. Here, F: tightening force, T: tightening torque, d: effective diameter, l: screw lead, μ: friction coefficient.
F = 2T / D
F = W (l + μπd) / (πd−μl)
Dividing the value of W × 24 (number of screws) by the area where the shower plate exchanges heat gives about 28.4 kgf / cm ² . Therefore, the cooling effect as shown in FIG. 11 cannot be expected unless the shower plate is pressed against the heat exchange surface of the upper lid with a force of 28.4 kgf / cm ² or more.

  When film formation is performed using the apparatus of the present invention (FIGS. 1 to 6), film formation with a good in-plane film thickness distribution can be performed with good reproducibility as described above (FIGS. 7 and 8).

  In addition, based on the results shown in FIGS. 9 to 11, in the apparatus configuration of FIG. 1, the structure in which the vacuum tank upper cover and the shower head shown in FIG. 6 are integrated is not used. A shower head structure is incorporated, the surface area of the shower plate is approximately the same as the area of the vacuum chamber ceiling, ensuring the maximum area, and the heat exchange area of the shower plate is 2.4 times or more that of the film forming gas passage. The oil circulation path in the upper lid is placed as close as possible to the surface where the shower plate is fixed to increase the heat exchange efficiency, and the screw hole that fixes the shower plate to the upper lid is processed into an island shape to maximize the oil circulation path. Therefore, if the measure for increasing the heat exchange efficiency is not used, the shower plate surface temperature is 25 in an environment where the distance between the shower head surface and the substrate is 40 mm or less and the substrate temperature is 580 ° C. or more. It can be said that it cannot be lowered below 0 ° C.

  In the structure of FIG. 1, when the distance between the shower plate and the substrate was 40 mm, the reaction space A was 3.6 L and the lower space B was 4.7 L. By eliminating the substrate stage lifting mechanism and fixing the substrate stage, the volume required as the lower space on the secondary side of the concentric isotropic exhaust port is about 1.3 times the reaction space, making the device compact. As described above, when the size of the exhaust path (r) = 3 mm (vertical distance: L = 70 mm or more), the in-plane quality is 3% or less. The film thickness distribution was stable and good reproducibility was obtained.

  In the apparatus structure of FIG. 1, the inert gas supplied into the vacuum chamber 1 from the opening 8 on the outer periphery of the upper lid is first introduced to the outside of the deposition preventing plate 6 and surrounded by the exterior of the deposition preventing plate and the inner wall of the vacuum chamber. Since it has a structure that enters the reaction space A from the jet port 9 after filling the deposition plate outer peripheral space, it is possible to prevent the deposition gas from entering the deposition plate outer peripheral space from the reaction space A, As a result, film formation did not occur on the inner wall of the vacuum chamber, and cleaning of the vacuum chamber became unnecessary.

  In addition, when forming high-ferroelectric films such as PZT, SBT, and BST, if these films crystallize, it is very difficult to remove the films by plasma cleaning or chemical dry cleaning. Therefore, in general, wet chemical cleaning such as nitric acid is used. Therefore, when a film is attached to a part other than a removable part such as an adhesion prevention plate, an operation that is unacceptable at a mass production site, such as “an operator rubs away with nitric acid” occurs. This apparatus has a structure that does not cause these dangerous operations.

FIGS. 12A and 12B schematically show the substrate stage of this example. FIG. 12A is a schematic cross-sectional view showing the arrangement of the vacuum tank upper lid and the shower plate, and FIG. 12B is a top view thereof. 12, the same components as those in FIG. 1 are denoted by the same reference numerals.
A SiC susceptor 16 is disposed on the heat source 15, and a substrate S and a substrate stage member 17 are disposed on the SiC susceptor 16. The substrate stage member 17 is made of Si ₃ N ₄ . The substrate S can be positioned by the substrate stage member 17. The substrate stage facing the shower plate is flat, and the substrate is only convex from the plane. In this way, only the substrate is convex, and a flat substrate stage is used thereafter, so that a film can be formed stably with good reproducibility without generating turbulence and convection near the substrate.

This SiC susceptor 16 has good thermal conductivity, and can transmit heat from the heat source 15 to the substrate S uniformly. Furthermore, since SiC does not easily change over time due to oxidation, such a configuration is suitable for a high-temperature process in which oxygen is used as a reaction gas and the substrate has a high temperature of 500 ° C. or higher.
Since the SiC susceptor 16 is directly above the heat source 15, it is exposed to a higher temperature than the substrate S. Therefore, when the film is exposed to the film forming gas, a film is deposited on the surface at a high speed. For this reason, in the present invention, in order to minimize the area where the surface of the SiC susceptor 16 contacts the film forming gas, it is preferable to arrange the substrate stage cover 5 which is a substrate stage member that covers the SiC susceptor.

The substrate stage member 17 is concentric with the susceptor and has a central portion that is slightly larger in diameter than the substrate diameter so that the substrate S can be positioned. The substrate stage member 17 is made of Si ₃ N ₄ with low thermal conductivity and good thermal shock characteristics, takes away the heat of the SiC susceptor 16, minimizes the action of breaking the soaking of the SiC susceptor, and It is considered not to break even in a rapid heating cycle of the heat source 15 (a cycle in which the temperature of the substrate is raised from room temperature to a film forming temperature in a short time). As described above, the SiC susceptor provided on the heat source to uniformly heat the substrate and the substrate stage member made of the Si ₃ N ₄ member having low thermal conductivity and good resistance to thermal cycle and oxygen gas are used. Thus, it is possible to configure a thin film manufacturing apparatus having a substrate stage in which the frequency of component damage is low and the generation of particles is low.

Although quartz was used for the substrate stage member in the development process of this apparatus, the contact portion with the SiC susceptor becomes high temperature, reacts with Pb and oxygen contained in the film forming gas, and Pb diffusion phenomenon into quartz or quartz O ₂ loss and loss-of-sight phenomenon occurred, and the characteristics changed. Also, erosion was noticeable in the nitric acid cleaning of parts.
In addition, Al ₂ O ₃ was used as the substrate stage member in the development process of this apparatus, but microcracks due to a rapid thermal cycle occurred at the contact portion with the SiC susceptor, and the substrate stage member was damaged. Moreover, the micro crack became a generation source of particles.

The substrate stage member made of Si ₃ N ₄ is required to process several thousand substrates / month in a mass production apparatus, and the members constituting the reaction space are subjected to acid cleaning by regular maintenance. It is selected taking into consideration that repeated resistance is required.
In the structure of the substrate stage, only the substrate is convex, and the flat substrate stage is used thereafter, so that a film can be formed stably with good reproducibility without generating turbulence and convection in the vicinity of the substrate.

  According to the present invention, in addition to the above, a gas exhaust path is configured by the cylindrical inner wall of the cylindrical vacuum chamber without unevenness and the outer side of the cylindrical substrate stage, or a substrate stage member having a shape other than the cylindrical shape is used. In this case, as a result, a gas exhaust path is constituted by the substrate stage member and the inner wall of the vacuum chamber so as to serve as a cylindrical substrate stage. By adjusting the gap and length of the gas exhaust path and forming an exhaust space at least 1.3 times the reaction space on the secondary side of the exhaust path, isotropic exhaust is realized, and a good film thickness distribution, A membrane rate can be obtained.

  In addition, a cylindrical or other shape reaction space is partitioned by a cylindrical tube having no irregularities to form a cylindrical reaction space, and a gas exhaust path is constituted by the cylindrical tube and the cylindrical substrate stage, Alternatively, a substrate stage member having a shape other than a cylindrical shape is used, and as a result, the substrate stage member serves as a cylindrical substrate stage, and a gas exhaust path is configured by the substrate stage and the inner wall of the vacuum chamber. The isotropic exhaust is realized by adjusting the gap and length of the gas and by constructing an exhaust space of 1.3 or more with respect to the reaction space on the secondary side of the exhaust path, and providing a good film thickness distribution and film formation rate. Obtainable.

In addition, by incorporating a shower head structure in the upper lid of the vacuum chamber, and taking advantage of the fact that the upper lid has the largest area as the ceiling of the vacuum chamber, take the maximum route for circulating the heating medium in the upper lid, and the shower plate on the upper lid The shower plate has almost the same area as the ceiling of the vacuum chamber, and the area of the heat exchange part between the shower plate and the top lid is 2.4 times the gas passage area of the shower plate, By pressing the shower plate against the upper lid with a force of 28.4 kgf / cm ² or more, the surface temperature distribution of the shower plate can be controlled to ± 10 ° C. or less even when the distance between the shower plate and the substrate is 40 mm or less. Can do. The same effect can be obtained even if the upper lid and the shower plate have a shape other than the disk.

Further, by connecting the vent gas line not only to the film forming gas line but also to the shower head, it is possible to prevent the particles from being rolled up during the venting and to prevent the particles from being scattered in the vacuum chamber.
Furthermore, by using a SiC susceptor provided on a heat source to uniformly heat the substrate, and a substrate stage member made of a Si ₃ N ₄ member having low thermal conductivity and good resistance to thermal cycling and oxygen gas. Thus, a thin film manufacturing apparatus having a substrate stage with a low frequency of component breakage and less particle generation can be configured.

  Furthermore, by combining the above application examples, the rectifying action that suppresses turbulence, convection, and thermal convection in the vacuum chamber and thus in the reaction space is maximized, and the film quality and film thickness distribution of the thin film generated on the substrate can be reduced. Thin film manufacturing equipment that can improve the film thickness distribution, film composition distribution, and film formation rate, improve and stabilize film formation, reduce film formation dust, reduce film formation inside the vacuum chamber, and achieve stable film formation. Can be established.

As described above, the present invention relates to a thin film manufacturing apparatus and a thin film manufacturing method capable of stably forming a thin film having a stable film quality and film performance over a long period with little or no generation of particles. Is. This apparatus and method can be used effectively when, for example, a metal oxide film or the like is manufactured in the electric / electronic field.
This apparatus is very effective as a mass production apparatus that requires low dust and good reproducibility in the industry. In addition, it is very effective especially in the CVD process using thermal energy.

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Top cover 3 Shower head 4 Substrate stage 5 Substrate stage cover 6 Adhering plate 6a Adhering plate lifter 7 Gas exhaust passage 8 Opening 9 Inert gas outlet 13 Gas spread part 14 Oil circulation path 16 Susceptor 17 Substrate Stage member A Reaction space B Lower space r Size of gas exhaust path L Vertical length of gas exhaust path

Claims (25)

A thin film that is a CVD device that forms a film by a chemical reaction on a substrate heated by a substrate stage by introducing a film forming gas into the reaction chamber through a shower head from the upper part of the reaction chamber, which is a reaction space of a vacuum chamber capable of controlling vacuum. In the manufacturing apparatus, the upper reaction space is configured by a substrate stage that does not rotate or move up and down, a shower head, and a deposition plate, and a concentric gap formed by the deposition plate and the substrate stage is provided as a gas exhaust path. An apparatus for producing a thin film, characterized in that an inert gas flows along a deposition plate from above a gas exhaust path, and a lower space is provided on the secondary side of the gas exhaust path. The thin film manufacturing apparatus according to claim 1, wherein a width of the gas exhaust path is 3 mm or more and 15 mm or less. A thin film manufacturing apparatus and a thin film manufacturing method, wherein the volume of the lower space is 1.3 times or more the volume of the reaction space. The said adhesion prevention board is equipped with the mechanism which can be raised / lowered at the time of board | substrate conveyance, and can be moved up and down at the time of film-forming, and can raise and lower so that a reaction space can be comprised. The thin film manufacturing apparatus according to claim 1. The shower head has a structure in which the shower head is incorporated in the upper lid of the vacuum tank, and the upper lid is temperature-controllable so that the temperature of the shower head can be controlled in accordance with film forming conditions. The thin film manufacturing apparatus according to any one of 4. The thin film manufacturing apparatus according to claim 1, wherein an outer side of the reaction space partitioned by the deposition preventing plate is configured to be filled with an inert gas during film formation. A vent line for introducing a vent gas into the vacuum chamber is provided through a shower head provided in the upper lid of the vacuum chamber so as to face the substrate stage on which the substrate is placed. Item 7. The thin film manufacturing apparatus according to any one of Items 1 to 6. 8. The thin film manufacturing apparatus according to claim 7, wherein the vent line shares a film forming gas line connected to a shower head. The thin film manufacturing apparatus according to claim 7, wherein a slow vent system is provided in the vent line. The thin film manufacturing apparatus according to any one of claims 1 to 9, wherein a distance between a surface of the shower head and a substrate placed on a substrate stage is 10 mm to 70 mm. The thin film manufacturing apparatus according to any one of claims 1 to 11, wherein an inner diameter of the vacuum chamber is larger than a diameter of a shower head surface, and a diameter of the shower head surface is larger than an inner diameter of a reaction space. The thin film manufacturing apparatus according to claim 11, wherein a difference between the inner diameter of the vacuum chamber and the diameter of the surface of the shower head is within 20 mm. The said shower head surface is comprised with the disk shaped shower plate, and the heat exchange means is provided in the contact surface of a vacuum tank upper cover and a shower plate, The one in any one of Claims 1-12 characterized by the above-mentioned. Thin film manufacturing equipment. 14. The thin film manufacturing apparatus according to claim 13, wherein the temperature control of the shower plate is performed by heat exchange with the upper lid of the vacuum chamber. The thin film manufacturing apparatus according to claim 13 or 14, wherein an area of a heat exchange part of the shower plate is 2.4 times or more of an area of a film forming gas passage part. The thin film manufacturing apparatus according to any one of claims 13 to 15, wherein the shower plate is pressed against the upper lid of the vacuum chamber with a force of 28.4 kgf / cm ² or more per unit area under atmospheric pressure. . The thin film manufacturing apparatus according to any one of claims 13 to 16, wherein the film forming gas passage portion of the shower plate has a thickness of 5 mm or less. The thin film manufacturing apparatus according to any one of claims 13 to 17, wherein a thickness of a heat exchange portion between the shower plate and a vacuum tank upper lid is larger than a thickness of a film forming gas passage portion. The thin film manufacturing apparatus according to any one of claims 1 to 18, further comprising means capable of controlling the temperature in the vacuum chamber in a range of room temperature to 250 ° C. A hole communicating with the shower plate and the upper lid of the vacuum chamber is provided, and a pressure measuring device is connected to the hole so that the pressure during film formation can be measured. The thin film manufacturing apparatus according to any one of 19. In the substrate stage, the substrate mounting portion on the surface thereof is made of a material having good thermal conductivity, and the substrate stage member in contact with the thermally conductive susceptor is made of a material having lower thermal conductivity than the substrate mounting portion. The thin film manufacturing apparatus according to claim 1, wherein the apparatus is a thin film manufacturing apparatus. The thin film manufacturing apparatus according to claim 21, wherein the susceptor is made of SiC, and the substrate stage member is made of Si ₃ N ₄ . An arbitrary flow rate of deposition gas controlled by a gas flow rate controller is introduced into a reaction space consisting of a substrate stage that does not rotate or move up and down, a shower head, and a deposition plate, via a shower head built into the upper lid of the vacuum chamber. And a substrate placed in a reaction space controlled to an arbitrary film formation pressure by a pressure adjusting valve, which is formed by a chemical reaction on a substrate heated by a substrate stage, and an excess film formation gas and A method for producing a thin film, characterized in that a reaction by-product gas is exhausted as an exhaust gas by an exhaust system to produce a thin film on a substrate. 24. The thin film manufacturing method according to claim 23, wherein an inert gas is allowed to flow from the upstream side to the downstream side of the gas exhaust path, which is a gap formed by the deposition preventing plate and the substrate stage, during the film formation. . The thin film manufacturing method according to claim 23 or 24, wherein the thin film manufacturing method is performed using the apparatus according to any one of claims 1 to 22.

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