Mobile plating system and method

An exemplary mobile plating system is provided for performing a plating process using virtually any known or available deposition technology for coating or plating as substrate. The mobile plating system may include a vacuum chamber positioned in a mobile storage volume, an external vacuum pump, and a control circuitry to control the operation of some or all of the operations of the external vacuum pump. The external vacuum pump is positioned in the mobile storage volume when the mobile plating system is in transit, and is positioned external to the mobile storage volume when the mobile plating system is stationary and in operation. The external vacuum pump may be mounted on a skid, and, in operation, the external vacuum pump couples with the vacuum chamber to assist with producing a desired pressure in the vacuum chamber. The external vacuum pump couples with the vacuum chamber using a flexible piping segment and/or dampening arrangement to reduce and/or eliminate any mechanical vibrations within the vacuum chamber and within the mobile storage volume due to the operation of the external vacuum pump.

 

What is claimed is:

1. A mobile plating system for performing a plating process, the mobile plating system comprising:

a mobile storage volume;

a vacuum chamber positioned in the mobile storage volume, the vacuum chamber having an internal volume large enough to contain a substrate to be plated that is the size of at least one reactor vessel head stud;

an external vacuum pump operable to be positioned within the mobile storage volume when the mobile plating system is in transit, and to operate external the mobile storage volume when the mobile plating system is stationary and in operation, the external vacuum pump operable to assist with producing a desired pressure in the vacuum chamber when the mobile plating system is stationary and in operation, and to couple with the vacuum chamber through a coupling that reduces at least some of the vibrations created by the operation of the external vacuum pump from being transmitted to the vacuum chamber;

a control circuitry operable to control the external vacuum pump;

a support structure operable to be positioned within the vacuum chamber and to support the substrate to be plated; and

a filament operable to hold a depositant within the vacuum chamber in relation to the support structure.

2. The mobile plating system of claim 1, further comprising:

an associated equipment that includes:

a dc power supply operable to generate a desired voltage at the substrate,

an rf transmitter operable to generate an rf signal at a desired power level at the substrate, and

a filament power control module operable to generate a current at a desired level at the filament.

3. The mobile plating system of claim 1, wherein the mobile storage volume is a trailer.

4. The mobile plating system of claim 1, wherein the mobile storage volume is a cargo box.

5. The mobile plating system of claim 4, wherein the cargo box is a SEA/LAND cargo box.

6. The mobile plating system of claim 1, wherein the mobile storage volume is a cargo volume of a truck.

7. The mobile plating system of claim 1, wherein the external vacuum pump is mounted on a skid.

8. The mobile plating system of claim 1, wherein the external vacuum pump is a mechanical pump.

9. The mobile plating system of claim 1, wherein the external vacuum pump is a roughing pump.

10. The mobile plating system of claim 1, wherein the external vacuum pump includes a roughing pump and a foreline pump.

11. The mobile plating system of claim 10, wherein the roughing pump is a mechanical pump that couples with the vacuum chamber using a first flexible piping segment, and the foreline pump is a mechanical pump that couples with the vacuum chamber through a second flexible piping segment.

12. The mobile plating system of claim 1, further comprising:

an internal vacuum pump operable to couple with the vacuum chamber to assist with producing the desired pressure in the vacuum chamber.

13. The mobile plating system of claim 12, wherein the control circuitry is operable to control the internal vacuum pump.

14. The mobile plating system of claim 12, wherein the internal vacuum pump is a diffusion pump.

15. The mobile plating system of claim 12, further comprising:

a cooling system operable to cool the internal vacuum pump.

16. The mobile plating system of claim 2, wherein the control circuitry is operable to control the dc power supply, the rf transmitter, and the filament power control module.

17. The mobile plating system of claim 1, wherein the support structure is operable to rotate the substrate and further comprising:

a motor operable to control the rotation of the support structure, and wherein the control circuitry is operable to control the motor.

18. The mobile plating system of claim 1, wherein the control circuitry is integrated into one control module.

19. A mobile plating system for performing a plating process, the mobile plating system comprising:

a mobile storage volume;

a vacuum chamber positioned in the mobile storage volume, the vacuum chamber having an internal volume large enough to contain a substrate to be plated;

an external vacuum pump operable to be positioned within the mobile storage volume when the mobile plating system is in transit, and to operate external the mobile storage volume when the mobile plating system is stationary and in operation, the external vacuum pump operable to assist with producing a desired pressure in the vacuum chamber when the mobile plating system is stationary and in operation;

a means for coupling the external vacuum pump to the vacuum chamber to reduce at least some of the vibrations created by the operation of the external vacuum pump from being transmitted to the vacuum chamber;

a control circuitry operable to control the external vacuum pump;

a support structure operable to be positioned within the vacuum chamber and to support the substrate to be plated; and

a filament operable to hold a depositant within the vacuum chamber in relation to the support structure.

TECHNICAL FIELD OF THE INVENTION

This invention relates in general to the field of mobile systems and deposition technology for plating and coating materials and more particularly to a mobile plating system and method.

BACKGROUND OF THE INVENTION

Deposition technologies for coating and plating materials and developing engineered surfaces may include any of a variety of deposition technologies. These deposition technologies may include, for example, vacuum deposition or physical vapor deposition ("PVD"), chemical vapor deposition ("CVD"), sputtering, and ion plating. Generally, these deposition technologies may involve the steps of: (a) preparing and cleaning the surface of the target or substrate; (b) establishing a vacuum or desired pressure level at designated operating parameters; and (c) performing the deposition. Such deposition technologies involve large, expensive, and complex systems, equipment, and machinery.

For example, many such deposition technologies require an expensive, bulky, and complex vacuum system to establish and maintain a vacuum at a designated operating pressure. Such a vacuum system may include, generally, a vacuum chamber, mechanical vacuum pumps, which may be used as roughing and foreline vacuum pumps, a secondary vacuum pump, such as a diffusion pump, a cryo pump, and/or a turbo molecular pump, and complex pressure gauges, such as an ion vacuum gauge. These vacuum systems often require complex piping and plumbing configurations that must be free of leaks so that the precise and desired operating pressures and parameters can be maintained and followed. Such complex piping and plumbing is particularly subject to leakage at turns in the pipes or joints where pipes interface due to interface problems and mechanical vibrations caused by the operation of the vacuum pumps.

Some or all of the vacuum pumps, such as a diffusion pump, may also require a large and complex cooling system that, often, uses hundreds or thousands of gallons of water that must be cooled and circulated prior and during the operation of the vacuum pump. This may require a large and bulky water cooling system that includes a large water storage tank and a refrigeration system to cool the water in the large storage tank.

Because deposition technologies involve such large, expensive, and complex systems, equipment, and machinery, such systems must, generally, be permanently installed at a location. When large parts or components, such as those weighing hundreds or thousands of pounds, or when bulky or hard to ship parts or components need to be coated or plated using one of the deposition technologies, about the only option is to permanently install such a system at or near such large or bulky components. This allows such large and bulky components to be moved only a short distance to be coated or plated.

Unfortunately, because this is such an expensive option, it is often cost prohibitive. The high expenses include, not only the cost in procuring the real estate and equipment, and in setting up such complex systems, but in maintaining the equipment and in hiring and employing personnel with the special expertise needed to successfully operate and maintain such systems. Problems also exist in designing a deposition technology system. All such systems require custom design work to meet the particular needs and circumstances of the installation. Turnkey deposition technology systems simply do not exist. As has been illustrated, the design, installation, operation, and maintenance of deposition technology systems are complex and expensive, and, as a result, the coating or plating of large and bulky components using deposition technologies is often not available, even though such large and bulky components may greatly benefit from the significant advantages offered by such deposition technologies.

In some cases, the availability of certain components or parts is so critical that, from either a safety and/or a financial standpoint, the risk of a shipping delay or lost shipment, no matter how small, is too great a risk to take, even if significant advantages could be gained through coating or plating. For example, a reactor vessel head stud that is used in a nuclear power plant is so crucial and unique, that the risk of a shipping delay or lost shipment during a plant outage, such as, for example, during a fuel reload at a nuclear power plant that occurs every couple of years or so, is too great to take. For example, for every day that a nuclear plant is kept off line because of a delay, hundreds of thousands or even millions of dollars may be lost. Thus, certain components or parts are so crucial that they would never be shipped to another location for plating or coating using deposition technologies, in spite of all of the significant advantages that may be realized through such deposition technologies.

SUMMARY OF THE INVENTION

From the foregoing it may be appreciated that a need has arisen for a mobile plating system and method that allows a plating system, including all associated sophisticated equipment and system to be conveniently provided at a user's location or virtually any desired location. In accordance with the present invention, a mobile plating system and method are provided that substantially eliminate one or more of the disadvantages and problems outlined above.

According to an aspect of the present invention, a mobile plating system for performing a plating process is provided. The mobile plating system includes a vacuum chamber positioned in a mobile storage volume, an external vacuum pump, and a control circuitry to control the operation of some or, in other embodiments, all of the operations of the external vacuum pump. The external vacuum pump is positioned in the mobile storage volume when the mobile plating system is in transit, and is positioned external to the mobile storage volume when the mobile plating system is stationary and in operation. The external vacuum pump may be mounted on a skid, and, in operation, the external vacuum pump couples with the vacuum chamber to assist with producing a desired pressure in the vacuum chamber. The external vacuum pump couples with the vacuum chamber using a flexible piping segment and/or dampening arrangement to reduce and/or eliminate any mechanical vibrations caused by the operation of the external vacuum pump. The vacuum chamber has an internal volume large enough to contain a substrate to be plated that is the size of at least one reactor vessel head stud. This provides a large enough volume to plate substrates or parts that are either large or small.

The present invention provides a profusion of technical advantages that include the capability to locate sophisticated deposition technologies, systems, equipment, and machinery for coating and plating at virtually any desired location, which substantially increases the availability of such important technology.

Another technical advantage of the present invention includes the capability to make coating or plating from deposition technologies available for large and bulky components and parts that cannot be shipped or cannot be easily shipped without having to incur the significant expense of designing, operating, and maintaining a complex system using deposition technology.

Yet another technical advantage of the present invention includes the capability to coat or plate mission critical components, such as reactor vessel head studs used at nuclear power plants. Because the present invention allows deposition technologies to be brought to the customer, unacceptable risks due to possible shipping delays or lost shipments are eliminated.

Another technical advantage of the present invention includes the capability to reduce or eliminate shipping costs, even for smaller components and parts or non-mission critical parts, and eliminate the need to incur the substantial expense and cost of designing, operating, and maintaining a complex system using deposition technology. This significantly reduces overall costs.

Still yet another technical advantage of the present invention includes the capability to operate noisy mechanical vacuum pumps, such as mechanical roughing and foreline pumps, external to the mobile chamber resulting in reduced mechanical vibrations and increased operational reliability of the mobile plating system.

Still yet another technical advantage includes the capability to use sophisticated cooling system, such as a water cooling system, within a mobile storage volume of the mobile plating system.

Yet another technical advantage includes the capability to use sophisticated deposition technology without producing or leaving behind any harmful waste byproducts. This is significant.

Other technical advantages are readily apparent to one skilled in the art from the following figures, description, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts, in which:

FIG. 1 is a schematic diagram that illustrates a system for plasma plating that can be used to plate materials, according to an embodiment of the present invention;

FIG. 2 is a top view of a vacuum chamber of a system for plasma plating that illustrates one embodiment of a platform implemented as a turntable;

FIG. 3 is a side view that illustrates the formation and dispersion of a plasma around a filament to plasma plate a substrate according to an embodiment of the present invention;

FIG. 4 is a sectional view that illustrates a deposition layer that includes a base layer, a transition layer, and a working layer;

FIG. 5 is a flowchart that illustrates a method for plasma plating according to an embodiment of the present invention;

FIG. 6 is a flowchart that illustrates a method for backsputtering using the system of the present invention, according to an embodiment of the present invention;

FIG. 7 is a top view of a mobile plating system according to one embodiment of the present invention;

FIG. 8 is a side view of a connection of an external vacuum pump to a vacuum chamber of the mobile plating system; and

FIG. 9 is a flowchart that illustrates a method for using a mobile plating system according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

It should be understood at the outset that although an exemplary implementation of the present invention is illustrated below, the present invention may be implemented using any number of techniques, whether currently known or in existence. The present invention should in no way be limited to the exemplary implementations, drawings, and techniques illustrated below, including the exemplary design and implementation illustrated and described herein.

Initially, a system and method for plasma plating is described in detail below in connection with FIGS. 1-6 to illustrate a type of deposition technology that may be used with the mobile plating system and method. Although it should be understood that the present invention is in now way limited to the exemplary plating or deposition technology illustrated and discussed in connection with FIGS. 1-6, and that the present invention may be used with virtually any known or available plating or deposition technique. Finally, an embodiment of the mobile plating system and method are described in detail in connection with FIGS. 7-9 that implements, as an example, the plasma plating system type of deposition technology detailed previously in connection with FIGS. 1-6.

FIG. 1 is a schematic diagram that illustrates a system 10 for plasma plating that can be used to plate any of a variety of materials, according to an embodiment of the present invention. The system 10 includes various equipment used to support the plasma plating of a substrate 12 within a vacuum chamber 14. Once appropriate operating parameters and conditions are achieved, a depositant provided in a filament 16 and a filament 18 may be evaporated or vaporized to form a plasma. The plasma will contain, generally, positively charged ions from the depositant and will be attracted to the substrate 12 where they will form a deposition layer. The plasma may be thought of as a cloud of ions that surround or are located near the substrate 12. The plasma will generally develop a dark region, near the closest surface of the substrate 12 from the filament 16 and the filament 18, that provides acceleration of the positive ions to the substrate 12.

The filament 16 and the filament 18 reside within the vacuum chamber 14 along with a platform 20, which supports the substrate 12. A drive assembly 22 is shown coupled between a drive motor 24 and a main shaft of the platform 20 within the vacuum chamber 14. In the embodiment shown in FIG. 1, the platform 20 is provided as a turntable that rotates within the vacuum chamber 14. The drive assembly 22 mechanically links the rotational motion of the drive motor 24 with the main shaft of the platform 20 to impart rotation to the platform 20. The rotation of the main shaft of the platform 20 is enhanced through various support bearings such as a base plate bearing 28 and a platform bearing 30.

As is illustrated, the vacuum chamber 14 resides or is sealed on a base plate 32. The vacuum chamber 14 may be provided using virtually any material that provides the appropriate mechanical characteristics to withstand an internal vacuum and an external pressure, such as atmospheric pressure. For example, the vacuum chamber 14 may be provided as a metal chamber or as a glass bell. In an alternative embodiment, the base plate 32 serves as the platform 20 to support the substrate 12. The base plate 32 may be thought of as part of the vacuum chamber 14.

The base plate 32 also provides mechanical support for the system 10 while allowing various devices to feed through from its bottom surface to its top surface within the vacuum chamber 14. For example, the filament 16 and the filament 18 receive power from a filament power control module 34. It should be noted that although two filament power control modules 34 are shown in FIG. 1, preferably, these two modules are implemented as one module. In order to provide power to the filament 16 and the filament 18, electrical leads must feed through the base plate 32 as illustrated in FIG. 1. Similarly, the drive motor 24 must also penetrate or feed through the base plate 32 to provide mechanical action to the drive assembly 22 so that the platform 20 may be rotated. The electrical feed through 26, described more fully below, also feeds through the base plate 32 and provides an electrical conductive path between the platform 20 and various signal generators, also described more fully below. In a preferred embodiment, the electrical feed through 26 is provided as a commutator that contacts the bottom surface of the platform 20, in the embodiment where the platform 20 is implemented as a turntable. The electrical feed through 26 may be implemented as a commutator and may be implemented as a metal brush which can contact the bottom surface of the platform 20 and maintain an electrical contact even if the platform 20 rotates.

The filament power control module 34 provides an electric current to the filament 16 and the filament 18. In one embodiment, the filament power control module 34 can provide current to the filament 16 for a particular duration, and then provide current to the filament 18 during a second duration. Depending upon how the filaments are configured, the filament power control module 34 may provide current to both the filament 16 and the filament 18 at the same time or during separate intervals. This flexibility allows more than one particular depositant material to be plasma plated onto the substrate 12 at different times. The filament power control module 34 preferably provides alternating current to the filaments, but may provide a current using any known method of generating current. In a preferred embodiment, the filament power control module 34 provides current at an amplitude or magnitude that is sufficient to generate enough heat in the filament 16 to evaporate or vaporize the depositant provided therein.

In order to ensure even heating of the depositant, which will be provided at or in the filament 16 or the filament 18, the current provided by the filament control module 34 will preferably be provided using incremental staging so that a more even heat distribution will occur in the depositant that is being melted within the vacuum chamber 14.

In a preferred embodiment, the platform 20 is implemented as a turntable and rotates using the mechanical linkage as described above. A speed control module 36, as shown in FIG. 1, may be provided to control the speed of the rotation of the platform 20. Preferably, the rotation of the platform 20 occurs at a rate from five revolutions per minutes to 30 revolutions per minute. It is believed that an optimal rotational rate of the platform 20 for plasma plating is provided at a rotational rate of 12 revolutions per minute to 15 revolutions per minute. The advantages of rotating the platform 20 are that the substrate 12 can be more evenly plated or coated. This is especially true when multiple substrates are provided on the surface of the platform 20. This allows each one of the multiple substrates to be similarly positioned, on average, within the vacuum chamber 14 during the plasma plating process.

In other embodiments, the platform 20 may be provided at virtually any desired angle or inclination. For example, the platform 20 may be provided as a flat surface, a horizontal surface, a vertical surface, an inclined surface, a curved surface, a curvilinear surface, a helical surface, or as part of the vacuum chamber such as a support structure provided within the vacuum chamber. As mentioned previously, the platform 20 may be stationary or rotate. In an alternative embodiment, the platform 20 includes rollers that may be used to rotate one or more substrates.

The platform 20, in a preferred embodiment, provides or includes an electrically conductive path to provide a path between the electrical feed through 26 and the substrate 12. In one embodiment, platform 20 is provided as a metal or electrically conductive material such that an electrically conductive path is provided at any location on the platform 20 between the electrical feed through 26 and the substrate 12. In such as a case, an insulator 21, will be positioned between the platform 20 and the shaft that rotates the platform 20 to provide electrical isolation. In another embodiment, the platform 20 includes electrically conductive material at certain locations on its top surface that electrically coupled to certain locations on the bottom surface. In this manner, the substrate 12 can be placed at an appropriate location on the top side of the platform 20 while the electrical feed through 26 may be positioned or placed at an appropriate location on the bottom side of the platform 20. In this manner, the substrate 12 is electrically coupled to the electrical feed through 26.

The electrical feed through 26 provides a dc signal and a radio frequency signal to the platform 20 and the substrate 12. The desired operational parameters associated with each of these signals are described more fully below. Preferably, the dc signal is generated by a dc power supply 66 at a negative voltage and the radio frequency signal is generated by an rf transmitter 64 at a desired power level. The two signals are then preferably mixed at a dc/rf mixer 68 and provided to the electrical feed through 26 through an rf balancing network 70, which provides signal balancing by minimizing the standing wave reflected power. The rf balancing network 70 is preferably controlled through a manual control.

In an alternative embodiment, the platform 20 is eliminated, including all of the supporting hardware, structures, and equipment, such as, for example, the drive motor 24, and the drive assembly 22. In such a case the substrate 12 is electrically coupled to the electrical feed through 26.

The remaining equipment and components of the system 10 of FIG. 1 are used to create, maintain, and control the desired vacuum condition within the vacuum chamber 14. This is achieved through the use of a vacuum system. The vacuum system includes a roughing pump 46 and a roughing valve 48 that is used to initially pull down the pressure in the vacuum chamber 14. The vacuum system also includes a foreline pump 40, a foreline valve 44, a diffusion pump 42, and a main valve 50. The foreline valve 44 is opened so that the foreline pump 40 can began to function. After the diffusion pump 42 is warmed or heated to an appropriate level, the main valve 50 is opened, after the roughing pump 46 has been shut in by closing the roughing valve 48. This allows the diffusion pump 42 to further reduce the pressure in the vacuum chamber 14 below a desired level.

A gas 60, such as argon, may then be introduced into the vacuum chamber 14 at a desired rate to raise the pressure in the vacuum chamber 14 to a desired pressure or to within a range of pressures. A gas control valve controls the rate of the flow of the gas 60 into the vacuum chamber 14 through the base plate 32.

Once all of the operating parameters and conditions are established, as will be described more fully below in connection with FIGS. 5 and 6 according to the teachings of the present invention, plasma plating occurs in system 10. The substrate 12 may be plasma plated with a deposited layer, which may include one or more layers such as a base layer, a transitional layer, and a working layer, through the formation of a plasma within the vacuum chamber 14. The plasma will preferably include positively charged depositant ions from the evaporated or vaporized depositant along with positively charged ions from the gas 60 that has been introduced within the vacuum chamber 14. It is believed, that the presence of the gas ions, such as argon ions, within the plasma and ultimately as part of the depositant layer, will not significantly or substantially degrade the properties of the depositant layer. The introduction of the gas into the vacuum chamber 14 is also useful in controlling the desired pressure within the vacuum chamber 14 so that a plasma may be generated according to the teachings of the present invention. In an alternative embodiment, the plasma plating process is achieved in a gasless environment such that the pressure within the vacuum chamber 14 is created and sufficiently maintained through a vacuum system.

The generation of the plasma within the vacuum chamber 14 is believed to be the result of various contributing factors such as thermionic effect from the heating of the depositant within the filaments, such as the filament 16 and the filament 18, and the application of the dc signal and the radio frequency signal at desired voltage and power levels, respectively.

The vacuum system of the system 10 may include any of a variety of vacuum systems such as a diffusion pump, a foreline pump, a roughing pump, a cryro pump, a turbo pump, and any other pump operable or capable of achieving pressures within the vacuum chamber 14 according to the teachings of the present invention.

As described above, the vacuum system includes the roughing pump 46 and the diffusion pump 42, which is used with the foreline pump 40. The roughing pump 46 couples to the vacuum chamber 14 through the roughing valve 48. When the roughing valve 48 is open, the roughing pump 46 may be used to initia