JP6582075B2 - Protection inside gas container by ALD coating - Google Patents

Description

  The present invention relates generally to atomic layer deposition (ALD). More specifically, the present invention relates to providing a protective coating by ALD.

Background of the Invention

  Here, useful background information is presented without adhering to any technology representative of the state of the art described herein.

  The Atomic Layer Epitaxy (ALE) method was invented by Dr. Tuomo Suntola in the early 1970s. Another generic term for this method is atomic layer deposition (ALD), which is used today instead of ALE. ALD is a special chemical deposition method by sequentially introducing at least two reactive precursor species into at least one substrate.

A thin film grown by ALD has a high density, no pinholes, and a uniform thickness. For example, in an experiment in which aluminum oxide was grown by thermal ALD from trimethylaluminum (CH ₃ ) ₃ Al, also called TMA, and water, the non-uniformity on the entire surface of the substrate wafer was only about 1%.

  One interesting application of ALD technology is the provision of protective coatings on surfaces.

Abstract

  According to a first exemplary aspect of the present invention, a method for protecting the interior of a gas container is provided. The method includes providing an intake / exhaust manifold including a port assembly attachable to a port of the gas container, and sequentially supplying a reaction gas into the gas container through the port assembly and the port. Sequentially exposing the interior of the gas container to a self-saturated surface reaction and pumping reaction residues from the gas container through the port and the port assembly.

  The gas container may be, for example, a gas container or a gas cylinder. A desired protective coating is formed inside the gas container by the sequential self-saturated surface reaction (by ALD). That is, the inside of the gas container may be coated using ALD so that all surfaces exposed to the reaction gas are finally coated inside the gas container.

  In some embodiments, the method includes attaching the port assembly to the port of the gas container. The port of the gas container may be a gas container opening. The gas container opening may be threaded.

  In some embodiments, the method includes delivering reaction residue and purge gas from the interior of the gas container by a vacuum pump attached to the exhaust side of the intake and exhaust manifold. The vacuum pump may provide one or more of the following effects. That is, the vacuum pump may be used to evacuate the gas container. The vacuum pump may be configured to send reaction residue from the gas container through the port assembly.

  The gas container may be used as a reaction chamber for ALD reaction. That is, in some embodiments, the gas container is used as a reaction vessel that is sealed by the port assembly. As a result, the occurrence of the sequential self-saturated surface reaction is limited within the gas container.

  In some embodiments, the gas container coated on the inner wall forms a hot wall reaction chamber that is heated by an external heater.

  In some embodiments, both gas intake and gas exhaust are performed through the same port or opening of the gas container. In some embodiments, the intake / exhaust manifold connected in an airtight manner to the gas container opens directly to the gas container, and provides an alternate supply of precursors necessary for performing the ALD process and an inert gas. Allows purge of the internal volume of the gas container and removal of the precursor, gaseous reaction products, and purge gas from the gas container.

  In some embodiments, the gas container can be closed (or closed) by the intake and exhaust manifold.

  In some embodiments, the port assembly includes a seal. In some embodiments, the sealing portion is detachable from the gas container opening instead of the gas container sealing valve. The said sealing part has a taper screw depending on embodiment. In some embodiments, the taper screw is configured to mate with a counter screw in the gas container opening. The sealing part may be sealed by turning and screwing into the gas container opening. In some embodiments, a sealing tape such as a Teflon (registered trademark) tape is provided between the threaded gas container opening and the taper screw in order to improve sealing performance. In some embodiments, at least one supply line and exhaust line passes through the seal. In some embodiments, the port assembly includes an attachment portion that is detachable from the sealing portion. The attachment portion may form a (cylindrical) extension of the sealing portion. In some embodiments, when the attachment portion is removed from the sealing portion, the sealing portion can be turned and tightened into the gas container opening. Depending on mounting, the attachment portion may be capable of rotating the sealing portion while the sealing portion is attached to the attachment portion. In some embodiments, at least one supply conduit and exhaust conduit penetrates both the sealing portion and the attachment portion. In some embodiments, the interface between the sealing portion and the attachment portion is sealed when the attachment portion is attached to the sealing portion. In some embodiments, an airtight feedthrough for passing at least one of a supply pipe line and an exhaust pipe line is provided at the end opposite to the mounting portion.

  In embodiments in which the gas container is placed in a deposition reactor such as a reaction chamber or a vacuum chamber, sealing by the port assembly prevents coating deposition on the chamber walls. This reduces the need to clean the chamber walls.

  In some embodiments, the gas container is used as a reaction vessel that is sealed by a seal included in the port assembly.

  In some embodiments, the sealing portion includes a taper screw that can be attached to and detached from the port of the gas container instead of a sealing valve.

  In some embodiments, the port assembly includes an attachment portion, the attachment portion can be attached to the sealing portion, and the sealing portion can be turned and fastened to the port of the gas container.

  In some embodiments, the method includes directing an inert purge gas to an intermediate section between the gas container and a surrounding chamber wall and pumping the inert purge gas out of the intermediate space.

  The overpressure generated by introducing the inert purge gas into the intermediate space further improves the sealing effect of the port assembly. In one embodiment, the intermediate space is maintained at a vacuum pressure by a vacuum pump in fluid communication with the intermediate space. By configuring the material flow from the intermediate space through the exhaust conduit to a pump such as the vacuum pump, the precursor material that has entered the intermediate space can be removed.

  The intake / exhaust manifold includes at least one supply pipe and an exhaust pipe. Precursor vapor is released from a discharge point in the gas container of the at least one supply line. The exhaust pipe starts from an exhaust point in the gas container. In some embodiments, the discharge point (ie, gas discharge point) in the gas container is located at a different level than the exhaust point (ie, gas exhaust point). In certain exemplary embodiments, the discharge point is at the lower end (ie, the lower end) of the gas container and the exhaust point is at the upper end (ie, the upper end). In another exemplary embodiment, the discharge point is at the upper end (ie, the upper end) inside the gas container and the exhaust point is at the lower end (ie, the lower end).

  In some embodiments, the intake and exhaust manifold includes one or more supply lines, and the control elements of each supply line are controlled by a control system implemented in a computer.

  In some embodiments, the intake / exhaust manifold includes an ALD reactor supply facility. In some embodiments, the supply facility comprises a supply line and at least the desired precursor and inert gas flow control elements, such as valves, mass flow controllers, etc., and their control systems.

  The control system may be implemented by software such as a laptop computer. That is, in some embodiments, the intake / exhaust manifold includes one or more supply lines, and the control elements of each supply line are controlled by a control system implemented in a computer. Appropriate replaceable precursor sources and inert gas sources may be attached to the supply facility.

  According to a second exemplary aspect of the present invention, an apparatus for protecting a gas container interior is provided. The apparatus is an intake / exhaust manifold including a port assembly attachable to a port of the gas container, and the apparatus sequentially supplies reaction gas into the gas container through the port assembly and the port. An intake / exhaust manifold configured to sequentially expose the interior of the gas container to a self-saturated surface reaction, and a pump configured to pump reaction residues from the gas container through the port and the port assembly. And comprising.

  In some embodiments, the gas discharge point provided by the intake / exhaust manifold is disposed at a different level from the gas exhaust point provided by the intake / exhaust manifold. The different levels here usually mean different heights.

  In some embodiments, the intake and exhaust manifolds include precursor vapor and purge gas supply lines and their control elements. The pump may be attached to an exhaust side of the intake / exhaust manifold. The pump may be a vacuum pump.

  In some embodiments, the intake / exhaust manifold includes a gas container specific port assembly configured to attach the intake / exhaust manifold to the port of the gas container, thereby A fluid communication path is formed between the inside of the gas container. Similarly, a fluid communication path is formed between the inside of the gas container and the pump.

  In some embodiments, the port assembly includes a seal that is attachable to the port of the gas container.

  In some embodiments, the sealing portion has a taper screw.

  In some embodiments, the apparatus includes an inert gas supply line configured to direct an inert purge gas to a chamber surrounding the gas container and to an intermediate space between the gas container and a wall of the surrounding chamber. With.

  The device comprising the intake / exhaust manifold may be mobile so that it can be moved to meet user needs. In some embodiments, the intake / exhaust manifold includes a separate intake manifold and exhaust manifold, and both manifolds can be connected to the gas container port at the same time, and operate in cooperation in a protection method inside the gas container. Designed to.

  Thus far, various embodiments have been illustrated that do not constrain the present invention. Each of the above embodiments is used only to illustrate selected aspects or steps utilized to implement the present invention. Some embodiments may have been presented only by reference to certain exemplary aspects of the invention. It should be understood that the corresponding embodiments are applicable to other exemplary aspects. These embodiments may be arbitrarily and appropriately combined.

  The present invention will now be described by way of example only with reference to the accompanying drawings.

FIG. 3 is a schematic diagram illustrating an apparatus and use of the apparatus to protect the interior of a gas container, according to one exemplary embodiment. FIG. 6 illustrates another supply configuration according to certain exemplary embodiments. FIG. 6 illustrates yet another exemplary embodiment. FIG. 6 illustrates a sealing configuration according to certain exemplary embodiments. FIG. 3 illustrates a method according to an exemplary embodiment.

Detailed explanation

  In the following description, an atomic layer deposition (ALD) technique is used as an example. The basics of ALD growth mechanisms are known to those skilled in the art. As mentioned in the introductory part of this patent application, ALD is a special chemical deposition method by sequentially introducing at least two reactive precursor species onto at least one substrate. By exposing at least one substrate to a precursor pulse that is time-divided in a reaction vessel, material is deposited on the surface of the substrate by sequential self-saturated surface reactions. In the context of the present application, the at least one substrate comprises the interior (inner surface) of a gas container, such as a gas container. Also, in the context of this application, the term ALD includes any applicable ALD-based technology and equivalent or closely related technology. An example of this is a molecular layer deposition (MLD) technique.

  A basic ALD deposition cycle consists of four consecutive steps: Pulse A, Purge A, Pulse B, and Purge B. Pulse A is composed of the first precursor vapor and pulse B is composed of the second precursor vapor. Inert gases and vacuum pumps are commonly used to purge gaseous reaction byproducts and residual reactant molecules from the reaction space during purge A and purge B periods. One deposition sequence includes at least one deposition cycle. The deposition cycle is repeated until the deposition sequence produces a thin film or film of the desired thickness. The deposition cycle can also be made more complex. For example, a deposition cycle can include three or more reactant vapor pulses, each separated by a purge step. All of these deposition cycles form a timed deposition sequence that is controlled by a logic unit or microprocessor.

  In certain exemplary embodiments described below, methods and apparatus are provided for protecting the interior of a gas container (such as a gas cylinder or gas container) with a protective coating. This gas container is a pressure vessel. The gas container itself forms a reaction chamber (ie, reaction space), generally there is no separate substrate, and the surface inside the gas container forms the substrate (where the substrate means the material to be processed) ). All these surfaces can be coated by ALD treatment. In the ALD process, the precursor vapor is sequentially supplied into the gas container through the intake / exhaust manifold. The reaction residue is pumped out from the gas container through the exhaust side of the intake / exhaust manifold. The gas container may optionally be heated before and / or during the ALD process by a heater placed around the gas container.

  FIG. 1 is a diagram illustrating a method and associated apparatus in a particular exemplary embodiment. An apparatus used for protecting the inside of the gas container 10 includes an intake / exhaust manifold 20. This device may be a mobile device. The mobile device may be moved as appropriate close to the gas container to be protected, if necessary.

  The intake / exhaust manifold 20 is configured to be removably attached to the gas container port 11. FIG. 1 shows an intake / exhaust manifold 20 attached to a gas container port 11 by a port assembly 24. The port assembly 24 may be a gas container specific part. The port assembly includes a sealing structure (not shown) that seals the interface between the gas container port 11 and the port assembly 24. In one exemplary embodiment, the port assembly comprises a seal (not shown). This seal is clamped to its opposite surface in the gas container port 11.

  The intake / exhaust manifold 20 includes an ALD reactor supply facility 70. The supply facility 70 includes necessary supply pipelines and their control elements. A first precursor vapor supply line 41, a second precursor supply line 42, and a purge gas supply line 43 are attached to the port assembly 24 shown in FIG. The first precursor supply line 41 is the first precursor source 21, the second precursor supply line 42 is the second precursor source 22, and the purge gas supply line 43 is the purge / inert gas source. 23 is the starting point. The supply lines 41 to 43 extend from the corresponding sources 21 to 23 to the inside of the gas container 10 through the port assembly 24 and the gas container port 11, respectively. The supply lines 41 to 43 terminate at their respective discharge points. The exhaust pipe line 32 starts from an exhaust point inside the gas container. The emission point should be located at a different level than the exhaust point in order to effectively obtain uniform deposition. In the embodiment shown in FIG. 1, the discharge points of the supply pipelines 41 to 43 are at the lower end of the gas container 10, and the exhaust point is at the upper end.

  The supply line control element includes a flow rate control element and a timing control element. A first precursor supply valve 61 and a mass (or volume) flow controller 51 in the first precursor supply line 41 control the timing and flow rate of the first precursor pulse. Similarly, a second precursor supply valve 62 and mass (or volume) flow controller 52 in the second precursor supply line 42 controls the timing and flow rate of the second precursor pulse. Further, the purge gas supply valve 63 and the mass (or volume) flow rate controller 53 control the timing and flow rate of the purge gas.

  In the embodiment shown in FIG. 1, the operation of the supply facility 70 is controlled by a control system. FIG. 1 shows a control connection 72 between a supply facility 70 and a control system 71. The control system 71 may be implemented by software such as a laptop computer, for example.

  In some embodiments, the ALD process inside the gas container is performed at a vacuum pressure. The intake / exhaust manifold 20 includes a vacuum pump 33. In some embodiments, the vacuum pump 33 is disposed at the end of the exhaust line 32 provided by the intake / exhaust manifold 20. The vacuum pump 33 can optionally be controlled by the control system 71 via an optional electrical connection 73 (between the control system 71 and the vacuum pump 33). In some embodiments, the gas container is heated by an external heater (not shown).

  During operation, the inside of the gas container 10 is evacuated by the vacuum pump 33. The precursor vapors of the first precursor and the second precursor are sequentially discharged from the discharge points of the first and second precursor supply lines 41 and 42 into the gas container, respectively. In the purge step, the inert purge gas is discharged from the discharge point of the purge gas supply line 43 into the gas container. Arrows 15 indicate the flow direction in the gas container from the respective discharge points of the precursor vapor and purge gas to the exhaust point (through which it is pumped to the exhaust line 32). By repeating the deposition cycle as necessary, a protective coating having a desired thickness is obtained on the inner surface of the gas container.

  Still referring to FIG. 1, it should be noted that in other embodiments, the configuration of the intake and exhaust manifold 20 may be different. Instead of separate supply lines, at least some of the plurality of supply lines may be shared. The type of valve may be different and the position of the flow control element may be different. For example, a three-way valve may be used in place of the two-way valve to immediately reflect the change in the supply pipeline route. The precursor source and purge gas are selected according to the mounting and desired coating. The gas container 10 may be heated from the outside of the gas container 10 by an optional heater 16. The heater may be a helical coil heater provided around the gas container 10. The operation of the heater can optionally be controlled via a connection by the control system 71.

  Coatings that can be applied depending on the application include, for example, metal oxides such as aluminum oxide, titanium oxide, tantalum oxide, tungsten carbide, and combinations thereof, but the coating is not limited to these materials.

  2A and 2B show two alternative embodiments for the arrangement of supply and exhaust lines within the gas container 10. The gas container 10 has an inner wall shaped so that the low-pressure gas can move freely.

  FIG. 2A corresponds to the configuration shown in FIG. That is, the supply pipelines 41 to 43 and the exhaust pipeline 32 extend through the gas container port 11. The supply lines 41 to 43 terminate at their respective discharge points. The exhaust pipe line 32 starts from an exhaust point. The discharge points of the supply pipes 41 to 43 are at the lower end of the gas container 10 and the exhaust point is at the upper end. The direction of gas flow is indicated by arrows 15.

  On the other hand, in the preferred embodiment shown in FIG. 2B, the exhaust line starts from the lower end of the gas container 10, and the discharge points of the supply lines 41 to 43 are at the upper end. The supply lines 41 to 43 and the exhaust line 32 extend through the gas container port 11. The supply lines 41 to 43 terminate at their respective discharge points. The exhaust pipe line 32 starts from an exhaust point. The direction of gas flow is indicated by arrows 15.

  FIG. 3 is a diagram illustrating a method and apparatus for protecting a gas container interior, according to another exemplary embodiment. This embodiment basically corresponds to the embodiment shown in FIG. 1, but discloses certain additional features.

  FIG. 3 shows a pressure vessel such as a chamber 30 surrounding the gas container 10. The chamber 30 may be, for example, a vacuum chamber or an ALD reaction chamber that is generally used in the field of ALD. The gas container 10 is loaded into the chamber 30 from the loading hatch 31 or the like, and is attached to the port assembly 24 by the port 11. The supply pipelines 41 to 43 are passed into the chamber 30 through a feedthrough 36 provided on the wall of the chamber 30. The exhaust pipe line 32 is passed to the outside of the chamber 30 through a feedthrough 46 provided on the wall of the chamber 30. The positions of the feedthroughs 36 and 46 vary depending on the implementation. Feedthroughs 36 and 46 may be implemented by a single feedthrough. Feedthroughs 36 and 46 are sealed.

  The basic operation relating to the deposition of the protective film in the gas container 10 is the same as that described with reference to FIG.

  The embodiment shown in FIG. 3 optionally includes a purge gas supply conduit 44. Via this conduit 44, an inert purge gas is led (released) into the intermediate space 40 between the gas container 10 and the wall of the surrounding chamber 30. The purge gas flows to the conduit 44 along the branch pipe 43a branched from the purge gas supply pipe 43, for example.

  The intermediate space 40 is exhausted by the vacuum pump 33 through an exhaust conduit 45 provided on the opposite side of the intermediate space 40. The exhaust pump 33 is in fluid communication with the intermediate space 40 via an exhaust conduit 47 extending from the exhaust conduit 45 to the exhaust pump 33. The exhaust lines 32 and 47 may join at any point on the path to the exhaust pump 33.

  By the pumping, a flow is generated in the intermediate space 40, and the precursor material that has entered the intermediate space 40 is guided to the exhaust pipe 47. The overpressure generated by introducing the inert purge gas into the intermediate space 40 further improves the sealing effect of the port assembly 24. An arrow 35 indicates the flow direction in the intermediate space 40.

  FIG. 4A is a diagram illustrating a sealing configuration according to one exemplary embodiment. The gas container 410 includes a gas container port 411. Here, the gas container port 411 is an opening of the gas container. The intake / exhaust manifold includes a port assembly that includes a seal 424. The sealing part can be attached to and detached from the gas container opening 411 instead of the gas container sealing valve, for example, by turning. For this reason, the sealing part 424 is a taper screw part. The taper screw of the sealing portion is configured to be fitted with an opposing screw (not shown) in the gas container opening 411 and tightened into the gas container opening 411 for sealing. As described above, the sealing portion 424 seals the gas container opening by, for example, turning and screwing into the gas container opening.

  In some embodiments, as shown in FIG. 4B, a Teflon tape or the like is provided around the taper screw between the threaded gas container opening 411 and the taper screw to improve sealability. The sealing tape 425 is provided. FIG. 4B is an enlarged view of the particular part shown in FIG. 4A.

  The two supply lines 441 and 443 and the exhaust line 432 shown in FIGS. 4A and 4B are configured similarly to the preferred embodiment of FIG. 2B. That is, the gas release point is very close to the gas container opening and the exhaust point is at the opposite end (ie, the lower end) of the gas container. The supply line and the exhaust line pass through the sealing portion 424 and extend into the gas container 410. In some embodiments, the port assembly further includes a mounting portion 426 that is detachable from the sealing portion. The mounting portion 426 forms a (cylindrical) extension of the sealing portion 424. Depending on the embodiment, when the attachment portion 426 is removed from the sealing portion 424, the sealing portion 424 can be turned and tightened into the gas container opening portion 411. Depending on the mounting, the attachment portion 426 may be capable of rotating the sealing portion 424 while the sealing portion 424 is attached to the attachment portion 426. The supply pipelines 441 and 443 and the exhaust pipeline 432 pass through both the sealing portion 424 and the attachment portion 426. The interface between the sealing portion 424 and the attachment portion 426 is sealed when the attachment portion 426 is attached to the sealing portion 424. In some embodiments, at least one of supply lines 441 and 443 and an exhaust line 432 is provided at the end of the attachment 426 opposite the end on the seal side (as shown at the top of FIG. 4A). An airtight feedthrough is provided for threading. Airtight feedthrough here basically means a feedthrough that allows gas to pass only through the conduit between the interior of a part and the exterior of the attachment 426. Similarly, an airtight interface allows gas to pass only through the interface from a component on the first side of the interface (eg, mounting portion 426) to a component on the second side (eg, sealing portion 424). It means the interface that can.

  In the embodiment in which the attachment portion is omitted, the feedthrough is preferably provided at the (upper) end of the sealing portion 424.

  For the general operation of the embodiment shown in FIGS. 4A and 4B, reference is also made to the embodiment shown in FIGS.

  FIG. 5 is a diagram illustrating a method according to one exemplary embodiment. In step 81, the intake / exhaust manifold is attached to the gas container. In step 82, ALD processing is executed. ALD processing involves sequentially exposing the interior of a gas container to a self-saturated surface reaction and pumping the reaction residue from the gas container. Finally, in step 83, the intake / exhaust manifold is removed from the gas container.

  Some of the technical effects of one or more of the exemplary embodiments disclosed herein are listed below, which do not limit the scope and interpretation of each claim. One technical effect is to protect the interior of the gas container with a conformal protective coating. Another technical effect is to coat only the inside of the gas container and not the outside. Yet another technical advantage is that the need to clean the surrounding chamber is reduced.

  It should be noted that some of the functions or method steps described above may be performed in a different order and / or simultaneously. Furthermore, one or more of the functions or method steps described above may be optional or combined.

The foregoing has provided a complete and useful description of the best mode for carrying out the invention, presently devised by the inventors, using non-limiting examples of specific implementations and embodiments of the invention. . However, it should be understood by those skilled in the art that the present invention is not limited to the details of the above-described embodiments, and can be implemented in other embodiments using equivalent means without departing from the features of the present invention. Is clear.

  Furthermore, some of the features of the above-described embodiments of the present invention may be effectively used without using other features as well. Accordingly, the above description is merely illustrative of the principles of the invention and is not to be construed as limiting the invention. Accordingly, the scope of the invention is limited only by the appended claims.

Claims (4)

A method for protecting the interior of a gas container,
Pumping through the gas container opening so that the interior of the gas container is evacuated;
Sequentially exposing the interior of the gas container to a self-saturated surface reaction by sequentially supplying the reaction gas into the gas container through the gas container opening;
Pumping the reaction residue from the gas container through the gas container opening;
Including
Providing an intermediate space between the gas container and the wall of the surrounding chamber;
Generating an overpressure by introducing an inert purge gas into the intermediate space ;
Further comprising, methods. The method of claim 1 , comprising vacuuming the intermediate space by pumping the inert purge gas from the intermediate space. An apparatus for protecting the interior of a gas container according to the method of claim 1 or 2, comprising:
Means for sequentially exposing the interior of the gas container to a self-saturated surface reaction by sequentially supplying the reaction gas into the gas container through the gas container opening;
Means for pumping through the gas container opening so that the interior of the gas container is evacuated, and pumping reaction residues from the gas container through the gas container opening;
With
Further comprising a chamber surrounding the gas container, and an inert gas supply pipe adapted to the intermediate space leads to inert purge gas between the gas container and the surrounding chamber walls, devices.   4. The apparatus of claim 3, further comprising means for vacuuming the intermediate space by pumping out the inert purge gas from the intermediate space.