US20150041326A1

US20150041326A1 - Conductive metal enhanced with conductive nanomaterial

Info

Publication number: US20150041326A1
Application number: US13/261,851
Authority: US
Inventors: Randall Reagan Buckner; Kyle Kissell; Howard Scott Horton; Clayton Charles Gallaway
Original assignee: Nanoridge Materials Inc
Current assignee: Nanoridge Materials Inc
Priority date: 2011-11-16
Filing date: 2012-11-15
Publication date: 2015-02-12
Also published as: WO2013072687A3; WO2013072687A2; EP2780494A2

Abstract

Electroplating systems and methods are provided that employ a structure for defining a zone of deposition for co-depositing metal and nanomaterial on a cathode. Materials that may be co-deposited include copper and carbon nanotubes Pulsed power may be employed to produce a more dimensionally uniform and/or more functionally uniform deposit.

Description

FIELD OF THE INVENTION

This invention is directed to electroplating systems and methods for co-depositing conductive material enhanced with conductive nanomaterial; to conductive material produced by such methods; in certain particular aspects, to copper enhanced by electro-deposition with carbon nanotubes; and, in certain particular aspects, to printed circuit boards with circuits made with such carbon-nanotube-enhanced copper.

BACKGROUND TO THE INVENTION

In electroplating processes, an electrode is plated with metal from a solution. Electroplating is an electro-deposition process in which an electric field applied to the solution moves metal ions to a cathode and then coats the cathode. The metal ions can be re-supplied by a consumable anode (a “sacrificial” anode) or an inert anode may be used (a non-consumable or “non-sacrificial” anode) from which metal ions enter the solution in a salt liquid form as the process is on-going. Ions from the solution are reduced by an electrical current and coat a conductive object, e.g. the cathode, with the material, such as a metal.
Certain known electroplating processes are analogous to a galvanic cell acting in reverse. The part to be plated is the cathode of the circuit. A sacrificial anode is made of a metal to be plated on the part. Both components are immersed in a solution called an electrolyte containing one or more dissolved metal salts as well as other ions that permit the flow of electricity. A power supply supplies a direct current, or a pulsed or intermittent current with an overall forward bias, to the anode, oxidizing the metal atoms that comprise it and allowing them to dissolve in the solution. At the cathode, the dissolved metal ions in the electrolyte solution are reduced into a nucleus for rebuilding the metal's crystalline structure at the interface between the solution and the cathode, such that they “plate out” (recrystallize) onto the cathode. The rate at which the anode is dissolved corresponds to the rate at which the cathode is plated via the current flowing through the circuit; as well as some chemical additives (e.g., levelers, brighteners, etc.) administered for controlling inhibition or acceleration of the nucleus and crystal building process. The ions in the electrolyte bath are continuously replenished by the anode.
Electroplating can be used for depositing a layer of material to achieve a desired property (e.g., abrasion and wear resistance, corrosion protection, lubricity, increased electrical conductivity, increased thermal conductivity, aesthetic qualities, etc.) to a surface that otherwise lacks that property. Electroplating can be used to make a part, to build up thickness on undersized parts, and to make circuit boards.
Electroplating processes that use a non-consumable, inert, or non-sacrificial anode are called “electro-winning processes.” In electro-winning, a current is passed from an inert or passivated metal anode through a liquid solution containing the metal ions to be deposited so that the metal is extracted as it is deposited in an electroplating process onto the cathode. In such processes, ions of the metal to be plated are periodically replenished in the bath solution as they are drawn out of it.
Initially as nuclei of a desired material, made up of components from the solution, are deposited on a cathode, they are composed in a “zone of nucleation” at the surface of the cathode. This is an area of relatively small dimensions (e.g., widths measured in Angstroms) and control of this area and the control of nucleation present a variety of problems, such as non-uniform formation of a deposited layer, non-uniform distribution of plated material, and interference with the co-deposition of secondary metals (e.g., alloys) or particular additives (e.g., carbon blacks, chlorides, and oxides).
The introduction of electrically conductive material into an electroplating electrolyte bath solution poses additional problems. Further problems are presented when the added electrically-conductive material is nanomaterial. FIG. 1 shows a typical prior art system for depositing metal on a cathode combined with electrically-conducting carbon nanotubes. It presents a schematic of an exemplary electrochemical co-deposition apparatus for forming nanocomposites with a metal and carbon nanotubes. Carbon nanotubes (“CNTs”), a source of metal ions (e.g. metal salt), in an electrolyte solution are provided in a reaction vessel V, which can be made of glass or ceramic. A power supply P with an ammeter and voltmeter is connected between an anode and a cathode. The carbon nanotube metal nanocomposite is shown forming on the cathode. Agitation of the liquid can be provided by a magnetic stirrer separated from the liquid by a spacer, by air sparging, or by the introduction of a shear or ultrasonic mixer either directly into the vessel or with a separate vessel. A reference electrode can be provided to monitor electrochemical activity. The carbon nanotubes can be pretreated with one or more surfactants in the electrolyte of the solution and this can also limit flocculation or agglomeration of the nanotubes out of the solution. Since the metal ions are generally positively charged as well, codeposition on the cathode occurs with metallic ions (such as Cu⁺²) and CNT both electrodepositing at the cathode where they are each electrochemically reduced or adsorbed.
In one known process, the electrolyte solution includes CuSO₄as a metal ion source, H₂SO₄as an electrolyte source, and single-walled carbon nanotubes, “SWNTs,” and other known desired materials. A metal/CNT co-deposition system is disclosed in U.S. Pat. No. 7,651,766.
Such systems present a variety of problems. As shown in FIG. 1, CNTs are supplied into the vessel V indiscriminately en masse and are able to quickly permeate the entire bath solution (hence methods using such systems are referred to herein as “saturation methods”). Non-uniform amounts of CNTs in the bath can result in a non-uniform deposition on a cathode. The CNTs can coalesce, ball-up, compress, condense and clump in undesirable masses. Since the CNTS are electrically conductive, they interfere with the electrochemical reaction between the cathode and the anode and thus they interfere with the movement of ions and with the desired deposition on the cathode. Saturation methods also, by their very nature, require an over-abundance of CNTs, most of which are never deposited on the cathode. This can result in waste, increased cost, and general inefficiency in the production rate. It is also possible in these “saturation methods” that nanotubes agglomerate and clog various parts, such as filters and piping of an electro-deposition tank; and that an undesirable deposition of excess nanotubes occurs on cathode surface(s) in the form of agglomerated nanotubes.
A variety of systems and methods are known for electroplating, for nano-enhancement of materials, for depositing materials, for reinforcing elastomers with carbon nanotubes, and for co-depositing metal with nanotubes; including, but not limited to (and solely by way of example) systems disclosed in these exemplary U.S. patents and applications (not an exhaustive listing): U.S. Pat. Nos. 3,037,923; 6,258,237; 6,280,697; 6,462,935; 7,250,147; 7,252,749; 7,304,103; 7,384,815; 7,455,757; 7,459,137; 7,575,933; 7,605,205; 7,691,359; 7,828,619; 7,781,756; 7,892,517 and 7,850,874; and U.S. patent application Ser. No. 11/437,180 filed May 19, 2006 (U.S. Pat. No. 7,651,766); Ser. No. 12/299,235 filed May 1, 2007 (U.S. Pat. No. 7,832,983); Ser. No. 10/561,712 (US 2007/0259994); and Ser. No. 11/589,305 filed Oct. 30, 2006 (US 2007/0199826)—all of which are incorporated fully herein by reference for all purposes.

BRIEF SUMMARY OF THE INVENTION

The present invention, in certain aspects, discloses electroplating systems for co-depositing metal and nanomaterials on a cathode; methods for using such systems; and objects made by such methods. These systems and methods using them can use sacrificial or non-sacrificial anodes. In certain aspects the nanomaterial: is electrically conductive; is carbon nanomaterial; and, in one particular aspect; is carbon nanotubes. Such co-deposits made with systems according to the present invention with methods according to the present invention can produce a product with enhanced electrical conductivity, enhanced thermal conductivity, enhanced strength, and/or enhanced hardness. The methods can be electro-winning methods or they can employ sacrificial anode(s).
In certain systems according to the present invention in which nanomaterial is added for co-deposition with a metal, a structure is used in an electroplating vessel to define a deposition zone adjacent a cathode thereby inhibiting the complete saturation with the nanomaterial of an entire plating bath in the vessel. In one particular aspect, copper with carbon nanotubes are co-deposited on a cathode in a multi-step process in which in a first step nanotube-enhanced copper is deposited; in a second step, copper alone is deposited; and in a third step again nanotube-enhanced copper is deposited. In one aspect, copper alone is deposited and then nano-enhanced copper according to the present invention is deposited.
In one aspect, the nanomaterial to be added is introduced into a space between the structure and the cathode. In another aspect, a pump system is provided that is directed to the defined deposition zone between the cathode and the structure. Another pump system may be used for the other space in the vessel. In one particular aspect, the structure is permeable to the bath solution, but not to the nanomaterial, further inhibiting the flow of the nanomaterial out from the zone of deposition.
In one aspect, the structure for defining the deposition zone is a body or plate spaced-apart from the cathode. In another embodiment, the structure is an open container that encloses the cathode on both side and, optionally, also at the bottom, while solution flow is permitted to and around the cathode. In another embodiment, the structure includes a frame from which nanomaterial flows from a plurality of orifices or nozzles toward the cathode and a permeable member is positioned over an opening of the frame through which electrolyte solution is flowable between the anode and the cathode, but which is impermeable to the nanomaterial.
In certain embodiments of systems according to the present invention two (or three, or more) anodes are used and material is deposited on both sides of a cathode or on only one side. Deposition can be done on multiple cathodes simultaneously. In one aspect, one or two structures are used to define a deposition zone or zones adjacent the cathode.
Any suitable desired object or thing may be made with systems according to the present invention, including, but not limited to, circuit boards, wires, electrical conductors, electrical connectors, solid plates, cylinders, tubes, bars, and components overcoated with a thin layer of silver or gold to enhance electrical connection between surfaces. Circuit boards may be made which have electrically conductive material on one or both sides; e.g., but not limited to, boards between 0.001 inch and 0.250 inch thick.
In certain aspects, methods according to the present invention include the pulsing, by control of a dual-acting power supply, of an electric field in an electroplating vessel to “knock off” or average high and low density areas, non-uniform deposit nodes and spikes on a cathode in or near a zone of nucleation so that a more uniform coating or layer is deposited. Uniform coatings are desirable from both a production standpoint and from a performance standpoint. In production, “high spots” of a coating can have a higher current density and therefore can be more attractive to the plating process, causing additional undesired plating to build up on high spots creating a non-uniform surface or burning. This can render an object unusable. A non-uniform coating can result in undesirable performance differences over an area of an object. For example, a circuit board with a non-uniform coating can have significant undesirable variations in performance and in heat production, conductance, and dissipation.
The metals that can be deposited by systems and methods according to the present invention include, but are not limited to: any metal that can be deposited electrochemically or electrostatically; and copper, silver, gold, aluminum, platinum, palladium, tin, titanium; iron, chromium, molybdenum, cobalt, nickel and zinc. The nanomaterials that can be deposited by systems and methods according to the present invention include, but are not limited to, carbon nanotubes (single-walled; double-walled; multi-walled); carbon fibrils; buckyballs; C60 buckyballs; and fullerenes responsive to an electric field so as to allow participation in an electroplating mechanism. In certain particular embodiments of systems and methods according to the present invention, the metal is copper and the nanomaterial is carbon nanotubes so that a nanotube-enhanced electrically conductive material is deposited. This nanotube enhancement can improve electrical conductivity, thermal conductivity, mechanical strength properties, tensile strength, Young's modulus, fatigue strength, and hardness. A material's temperature coefficient or the change in the material's electrical resistance as a function of temperature can also be improved and also the attenuation and electrical impedance of a metal/nanotube composite, e.g., a copper/carbon nanotube composite.
Electro-processes according to the present invention include electro-deposition, electroplating, electro-polishing and electro-winning and certain systems according to the present invention include: a vessel; a cathode in the vessel onto which material can be deposited by an electro-process that is one of electro-deposition, electroplating, and electro-winning; an anode in the vessel spaced apart from the cathode; wherein the material for deposition onto the cathode includes a metal; a structure in the vessel between the cathode and the anode for defining a deposition zone therebetween, the structure for feeding nanomaterial into the deposition zone; the structure having filter material impermeable to the nanomaterial to facilitate maintenance of the nanomaterial in the deposition zone, and a dosing system for providing nanomaterial to the structure in doses.
Systems according to the present invention are usable in methods according to the present invention that include introducing an electroplating bath into a vessel of a system for electroplating, the system for electroplating comprising any system described herein according to the present invention, and electroplating the cathode or at the cathode using the system. Such a method can also include: making a thing by electroplating at the cathode of the system; smoothing a surface of a deposited layer deposited at the cathode by pulsing power to the system (“electro-polishing”); and/or smoothing a surface of a deposited layer deposited at the cathode by controlling the zone of nucleation at the cathode with inhibiting, leveling, or grain refining chemicals.
In certain aspects, the present invention provides methods and systems in which a plating current density is in a range of 1-50 Amps/square-foot for direct current plating and in a range of 2-100 Amps/square-foot for pulse plating.
Accordingly, the present invention includes features and advantages which are believed to enable it to advance electro-process technology for the co-deposition of metal and nano material. It is an object of at least certain preferred embodiments of the present invention to provide:
new, useful unique, efficient, nonobvious electroplating systems and methods for co-depositing metal and nanomaterial, e.g, electrically conductive nanomaterial, e.g. carbon nanotubes; and such new, useful, unique, efficient, nonobvious systems and methods in which a structure contributes to the definition of a deposition zone adjacent a cathode to enhance the deposition of nanomaterial on the cathode, to reduce the needed amount of nanomaterial to achieve the desired deposition level, to achieve a more uniform deposit, and/or to increase the efficiency of the system; and
new, useful unique, efficient, nonobvious systems and methods are provided in which an electric field in an electroplating vessel is pulsed to form a more uniform coating or layer of deposited material, e.g., metal and nanomaterial, on a cathode.

BRIEF DESCRIPTION OF THE DRAWINGS

How the invention may be put into effect will now be described by way of example only with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of a prior art electroplating system;

FIG. 2A is a schematic view of an electroplating system according to the invention;

FIG. 2B is a view in side section of a deposition zone structure for location adjacent a cathode for an electroplating system;

FIGS. 3 and 4 are a side sectional views of electroplating systems;

FIG. 4A is a rear view of nanomaterial introduction apparatus forming part of a system as in FIG. 4, FIG. 4B is a front view of a frame of the apparatus of FIG. 4A, FIG. 4C is a side view of a membrane of the apparatus of FIG. 4A, FIG. 4D is a front view of the membrane of FIG. 4C, FIGS. 4E-4G are sectional views of exit channels usable with the apparatus of FIG. 4A;

FIGS. 5, 6 and 7A are views in side section of electroplating systems;

FIG. 7B is a top view of a circuit board, FIG. 7C is a top view of a circuit board for a printed circuit board motor, FIG. 7D is a side view of a circuit board, FIG. 7E is a top view of an electrical contact and FIG. 7F is a side view of a circuit board, all of which can be made using the electroplating system of the invention;

FIG. 8 is a side sectional view of a plating system; and

FIG. 9 is a top view of a circuit board made with a system according to the present.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 2A shows a system 20 according to the present invention for electroplating metal from an electrolyte solution bath 21 in a vessel V onto an outer surface of a cathode C. A power supply system 23 with a control system 23 c supplies electric current to an anode A so that a resultant electric field E between the cathode C and the anode A reduces metal ions from the solution and deposits them onto the cathode C. As is true for every description herein, nanomaterial, CNTs, zones of nucleation, vessels, spaces within vessels, deposited material, and system components are not to scale.
A layer 22 of co-deposited metal and nanomaterial NM is formed on the cathode C. A plate 24 is mounted in the vessel adjacent and spaced-apart from the cathode C between the cathode C and the anode A. Optionally, the nanomaterial NM is introduced anywhere in the vessel, or, as shown, the nanomaterial NM is introduced into the bath 21 between the plate 24 and the cathode C.
The plate 24 may be made of material that is not electrically conductive. It may be made of material that is permeable to the electrolyte solution and to ions therein, but which is not permeable to the nanomaterial NM, e.g., with nanomaterial having a largest dimension of one to five microns and the plate impermeable to material having a largest dimension of one to five microns or more.
In one embodiment, the nanomaterial NM is electrically conductive nanomaterial. In one embodiment, the electrically conductive nanomaterial is carbon nanotubes. In one particular embodiment, the carbon nanotubes are single-walled carbon nanotubes.
FIG. 2B shows a structure 26 which is usable in systems according to the present invention as is the plate 24 to define a deposition zone around a cathode. The structure 26 is, generally, an open container, bag, or tube that has a mouth or opening 27 into which nanomaterial is introduced for deposition onto a cathode D. The structure 26 may be made of material that is not electrically conductive, and/or it may be made of a material that is permeable to the electrolyte solution and ions therein, but which is not permeable to the nanomaterial introduced into the structure.
FIG. 3 shows a system 30 according to the present invention which is like the system 20 (and like numerals in FIGS. 2 and 3 indicate like parts) for forming a layer 31 of co-deposited material on a cathode C. The system 30 has a structure 32 between the cathode C and the anode A that functions in a manner similar to the plate 24, FIG. 2, and the structure 26, FIG. 2B. The structure 32 supplies nanomaterial NR to a deposition zone adjacent the cathode C. A controlled dosing system T provides the nanomaterial to the structure 32. In one aspect a dosing system includes a dispersion chamber that facilitates nanomaterial processing and a peristaltic pump that periodically injects an aliquot of nanomaterial into the structure 26. The aliquot volume and injection rate can be adjusted for good or optimal nanomaterial integration into deposited metal.
A pumping system 33, optionally with sonication apparatus 34, recirculates fluid with nanomaterial NR therein between the structure 32 and the cathode C. This also has some recirculation effects on the remaining space within the vessel V. An optional pumping system 35, optionally with sonication apparatus 36, recirculates fluid in the bath 21 and also has some recirculation effects on the space between the structure 32 and the cathode C. Any pump, pump system, and/or sonicator used with this system (or with any system according to the present invention) may be periodically turned on and off (pulsed) to facilitate mixing and the dispersion of material. Any pumping and/or mixing/sonication apparatus herein may be used in any system herein (e.g., including the systems S, 33 and 35).
FIG. 4 shows a system 40 according to the present invention with a structure 42 for introducing nanomaterial between the cathode C and the structure 42. The system 40 is like other systems herein in some respects and like numerals in FIGS. 2 and 3 indicate like parts. In certain aspects, the left side (as viewed in FIG. 4) of the structure 42 is between one-eighth inch and one inch from the surface of the cathode. In one particular aspect, this distance is one half inch.
The structure 42 applies nanomaterial NL into a space between the cathode C and the structure 42 which flows to the structure 42 from a dosing system SM (e.g., like the system T, FIG. 3).
FIGS. 4A-4E show an apparatus 41 which is one embodiment of the structure 42. The apparatus 41 has a frame 41 f with flow channels 41 a and 41 b for receiving the nanomaterial NL from a supply system (e.g., a dosing system SM), and for supplying the nanomaterial into the space between the cathode C and the apparatus 41. In one aspect, the supply system supplies a dose of nanomaterial every minute. In one aspect, about two percent of the total amount of nanomaterial to be used is added every minute.
The nanomaterial NL flows into and through the channel 41 a, from there into and through the channel 41 b, and from the channel 41 b to the openings 41 c and then out from openings 41 c. The frame 41 f has an open area 41 d through which fluid is flowable. Each opening 41 c may function as a nozzle.
A membrane 43 is secured to the frame 41 f (e.g., tacked, glued, clipped, screwed) over the opening 41 d. In certain aspects, the membrane 43 (not shown to scale in FIGS. 4C, 4D) is not permeable to the nanomaterial NL so that it facilitates the maintenance of the nanomaterial within the space between the frame 41 f and the cathode C, thereby facilitating deposition of the nanomaterial NL onto the cathode C. In one aspect the membrane is made of one micron (pore size) polypropylene filter media (nanomaterial of one micron or more in largest dimension is not passable through it).
In one aspect, the backside of the cathode C is located against, or a relatively short distance from, an interior wall of the vessel V so there is little or no voltage differential on the cathode's backside and, therefore, little or no plating occurs on this backside. This relatively smaller space also results in relatively less nanomaterial being available to plate onto this backside.
FIG. 4E shows an exit opening 41 c of a channel 41 b of the frame 41. FIG. 4F shows a channel 41 e for nanomaterial application to a deposition zone. FIG. 4G shows a channel 41 f for nanomaterial application to a deposition zone. A nozzle or nozzles may be used with each opening 41 c. FIG. 5 shows a system 50 according to the present invention which has a cathode CC between two anodes AA and BB in an electrolyte solution bath BT in a vessel VV. Electrical current is supplied by a power system PS controlled by a control system SY. Electric fields EA and EB reduce and move ions to plate both sides of the cathode CC, (layers CA, CB).
The solution BT, in some aspects, includes metal ions of an electrically conductive metal and electrically conductive nanomaterial for plating onto the cathode CC; in one aspect, copper ions and carbon nanotubes. The nanomaterial may be fed or introduced into the vessel VV in any manner and/or with any device or apparatus shown or referred to herein. Any pump, pumping system, and related apparatus (e.g., stirrer, mixer, and/or sonication apparatus) disclosed or referred to herein may be used with the system 50.
A permeable bag 54 encompasses the anode which is permeable to the electrolytic solution and metal ions, but impermeable to undesirable materials in the vessel, e.g., oxides and chlorides, e.g., copper oxide and copper chloride. The anode BB has no such bag and is “nude” so that such a bag does not inhibit, distort, reduce, or degrade the electric field EB, thereby providing better control of the field EB and reducing current requirements. In one aspect, a bag 54 is made of five micron rated polypropylene filter media.
FIG. 6 shows a system 60 according to the present invention which has some parts and components like those of the system 50 (and like numerals and labels indicate like parts). The system 60 also includes a structure 62 between the anode BB and the cathode CC which defines a deposition zone DZ (the structure 62 like any such structure according to the present invention for use in defining a deposition zone, including, but not limited to the structures and frames of FIGS. 2A, 2B, 3 and 4).
Optionally, or instead of the structure 62, the system 60 has a structure 64 between the anode AA and the cathode CC which defines a deposition zone DP (the structure 64 like any such structure according to the present invention for use in defining a deposition zone, including, but not limited to the structures and frames of FIGS. 2A, 2B, 3 and 4).
An electrolyte solution BA used in the system 60, in some aspects, includes metal ions of an electrically conductive metal and electrically conductive nanomaterial for plating onto the cathode CC; in one aspect, copper ions and carbon nanotubes. The nanomaterial may be fed or introduced into the vessel of the system 60 in any manner and/or with any device or apparatus shown or referred to herein. Any pump, pumping system, and related apparatus (e.g., stirrer, mixer, and/or sonication apparatus) disclosed or referred to herein may be used with the system 60.
Optionally, the anode AA is encompassed by a bag 65 (shown in dotted line; like the bag 54 of the system 50). Optionally, the anode BB in the system 60 may also be encompassed by a bag (not shown) like the bag 65.
FIG. 7A shows an electroplating system 70 according to the present invention for making a circuit board by co-depositing metal and electrically conductive nanomaterial from an electrolyte solution bath 71 in a vessel VE onto an outer surface of a cathode CE which provides the substrate for the circuit board to be made. A power supply system 73 with a control system 73 c supplies electric current to an anode AD and that an electric field EF between the anode AD and the cathode CE reduces metal ions from the solution and moves them to the cathode CE. A structure 76 defines a deposition zone 77 between the structure 76 and the cathode CE. The structure 76 may be like any deposition-zone-defining structure disclosed herein.
Nanomaterial NA is supplied by the structure 76 (indicated by arrows labeled NA). A layer 72 of co-deposited metal and nanomaterial NA is formed on a foil layer 74 applied to the cathode CE prior to installation of the cathode CE in the vessel VE. In one aspect, the deposition structure 76 is like the structure 42, FIGS. 4 and 4A-4E; the foil layer 74 is a layer of copper about one to three mils thick; the deposited metal from the electrolyte solution is copper; and the deposited nanomaterial is single-walled carbon nanotubes. The electrolyte solution bath 71 contains deionized water, CuSO₄as a metal ion source, H₂SO₄as an electrolyte source, and, optionally, organic brighteners and/or leveling agents. Circuit boards of any desired dimensions and with any desired circuit board substrate may be made with a system like the system 70; including, but not limited to, circuit boards as shown in FIGS. 7B-7D.
FIG. 7B shows a circuit board 78 a made with a system like the system 70. In one aspect, the circuit board 78 a is like the circuit board disclosed in U.S. Pat. No. 5,334,898, incorporated fully herein for all purposes. FIG. 7C shows a circuit board 78 b made with a system like the system 70. In one aspect, the circuit board 78 b is a circuit board for a printed circuit board motor like that disclosed in U.S. Patent Application Publication No. 2006/0202484, incorporated fully herein for all purposes. It is within the scope of the invention to make, among other things, a circuit board with printed electrically conductive material on both sides of a substrate. A circuit board 78 c as shown in FIG. 7D, to be made by a system according to the present invention, has a substrate 78 s, a circuit 78 x on one side of the substrate 78 s, and a circuit 78 y on the other side of the substrate 78 s FIG. 7E shows an electrical connector 79 (top view) made with a system according to the present invention. FIG. 7F shows a plate 7 made with a system according to the present invention (any suitable system herein). In one aspect, a plate 78 p according to the present invention is generally rectangular and has a thickness between 0.001 inch and 0.250 inch. In one aspect, this plate has any desired width and any desired length.
FIG. 8 shows a system 80 according to the present invention for electroplating material in a layer 85 onto a cathode (“Cathode”) in a vessel (“Vessel”) which has an anode (“Anode”) in an electrolyte bath (“Bath”) in the vessel. A power system (“Power Pulsing System”) periodically supplies power so that an electric field (“Electric Field”) is pulsed (e.g., but not limited to, plating for about twenty milliseconds and then reversal of the electric field for about two milliseconds), which results in a non-continuous deposition of material on the cathode. The power system is configured to pulse the power for a period that is within the range 20-40 milliseconds e.g. one of:
about twenty milliseconds and then the power is reversed for about two milliseconds to reverse the electric field;
about twenty-five milliseconds and then the power is reversed for about five milliseconds to reverse the electric field;
about forty milliseconds and then the power is reversed for about six milliseconds to reverse the electric field; and
about thirty milliseconds and then the power is reversed for about five milliseconds to reverse the electric field.
Nanomaterial may be fed or introduced into the vessel in any manner and/or with any device or apparatus shown or referred to herein. Any pump, pumping system, and related apparatus (e.g., stirrer, mixer, and/or sonication apparatus) disclosed or referred to herein may be used with the system 80. This pulsing provides a time period between pulses in which metal ions can nucleate and then crystallize on the cathode surface. This pulsing also provides a reverse burst of electric energy that impacts more prominent or outstanding portions of a deposit in the layer 85 on the cathode in or near the zone of nucleation. For example, spikes 82 a and 82 b, nodes 83 a and 83 b, and deposits 84 a and 84 b can be shortened, diminished, reoriented, or disconnected (temporarily) by a reverse pulse of energy so that the layer 85 is more uniform in thickness. Such pulsing also has a desirable impact on individual nanomaterial pieces and on masses of nanomaterial. In certain aspects, such pulses may flatten nanotubes and/or reorient them in a more laminar direction—all or part of poorly oriented nanotubes. Such pulsing, which is done by a rapid change from cathodic to anodic potential, has an overall cumulative forward bias so that there is net deposition at the cathode. Such pulsing can be used with a variety of electroplating systems and with any system disclosed herein according to the present invention.
FIG. 9 shows a circuit board 90 according to the present invention which includes a board substrate 92 which is glass-reinforced epoxy material, known as “FR4 board.” This board substrate 92 was mechanically laminated with copper to a thickness of 0.7 mils (seven ten-thousandths of an inch) and this layer of conventional copper served as the substrate (cathode) for the electrical co-deposition of metal and nanomaterial as described above. Then a photoresist “image” was applied to the board in the design of the desired circuit; in this case, producing a circuit in the form of a circuit 94 with leads 94 a and 94 b. The photoresist material is an acid-resistant, insulating, photopolymer (cured or polymerized by exposure to ultraviolet or visible light). The photoresist “masks” or protects areas of the substrate, only allowing for metal or metal/nanomaterial deposition to occur in desired areas or patterns. The length “a” indicated in FIG. 9 of the circuit 94 is about 621 inches, the line width is about 20 mils (0.02 inches), and the lines of the circuit are about 25 mils apart.
The optional items 96 a, 96 b, and 96 c are intended for additional electrical and thermal property measurements of the co-deposited metal/nanomaterial. As one example, items 96 a, 96 b, and 96 c can be used to determine the current carrying capacity of the co-deposited metal/nanomaterial. In this test, electrical current is supplied by a power supply (either direct or alternating current). The applied current is increased until the metal/nanomaterial fails and then the maximum current carrying capacity is calculated in Amps/cm2. In processes according to the present invention, electroplating current density ranges between 1 to 50 Amps/square-foot for direct current plating and a range of 2-100 Amps/square-foot for pulse plating.
Comparing the circuit 94 made with nano-enhanced copper according to the present invention with a circuit made with copper of conventional purity (about 99.9% copper) the current carrying capacity of the circuit 94 is 5.6×10⁴Amps/cm²and that of a similar circuit without nano-enhanced copper is 3.9×10⁴Amps/cm².
It will be appreciated that the foregoing detailed description is provided for purposes of illustration only, and that modifications may be made to the embodiments described herein without departing from the invention.

Claims

1.-29. (canceled)

30. A system for electroplating comprising a cathode onto which material can be deposited, an anode spaced apart from the cathode, and a structure between the cathode and the anode for defining a deposition zone therebetween, wherein the material for deposition onto the cathode includes a metal and nanomaterial.

31. The system of claim 30 wherein the metal is copper and the nanomaterial is carbon nanotubes.

32. The system of claim 30, wherein a structure is provided for feeding nanomaterial into the deposition zone.

33. The system of claim 32, wherein the structure is configured for dosing nanomaterial into the deposition zone.

34. The system of claim 32, wherein the structure includes a frame with a plurality of spaced-apart openings through which nanomaterial can flow to the deposition zone.

35. The system of claim 32, wherein the structure has filter material impermeable to the nanomaterial.

36. The system of claim 32, wherein the structure has membrane material impermeable to the nanomaterial.

37. The system of claim 30, further comprising a recirculating pump system for recirculating the material to the deposition zone.

38. The system of claim 30, further comprising a dosing system for providing the nanomaterial to the structure in doses.

39. The system of claim 38 wherein a chosen total amount of nanomaterial is introduced into the deposition zone and the dosing system supplies about two percent of the chosen total amount of nanomaterial every minute.

40. The system of claim 30, further comprising a vessel, the vessel having an interior wall,

the cathode having a reverse side which does not define any part of the deposition zone,

the reverse side of the cathode located against, or a relatively short distance from, the interior wall of the vessel so there is little or no voltage differential on the cathode's backside so that little or no plating occurs on the reverse side.

41. The system of claim 30, further comprising a power system for periodically supplying power to the system so that material is non-continuously deposited on the cathode.

42. The system of claim 41 wherein the power system is configured to pulse the power for a period that is one of:

about twenty milliseconds and then the power is reversed for about two milliseconds to reverse the electric field;

about twenty-five milliseconds and then the power is reversed for about five milliseconds to reverse the electric field;

about forty milliseconds and then the power is reversed for about six milliseconds to reverse the electric field; and

about thirty milliseconds and then the power is reversed for about five milliseconds to reverse the electric field.

43. The system of claim 41, configured so that periodically supplying power produces a wider zone of nucleation to affect smoothing of portions of a deposit in a deposition layer on the cathode in or near a zone of nucleation on the cathode.

44. The system of claim 30 wherein the nanomaterial is one of or includes electrically conductive nanomaterial, carbon nanotubes, and single-walled carbon nanotubes, and further comprising a power system for periodically supplying power to the system so that an electric field is pulsed between the cathode and the anode so that material is non-continuously deposited on the cathode.

45. A thing made by the system of claim 30.

46. The thing of claim 45 which is one of circuit board, circuit board for printed circuit motor, electrical contact, cylinder, bar, tube, and plate.

47. A method for making a plated product, comprising

introducing an electroplating bath into a vessel of a system, the system comprising a cathode onto which material can be deposited, an anode spaced apart from the cathode, and a structure between the cathode and the anode for defining a deposition zone therebetween, wherein the material for deposition onto the cathode includes a metal and nanomaterial, and

electroplating the cathode using the system.

48. The method of claim 47, further comprising smoothing a surface of a layer deposited at the cathode by pulsing power to the system.

49. The method of claim 48, further comprising smoothing a surface of a layer deposited at the cathode by controlling the zone of nucleation at the cathode with inhibiting, leveling, or grain refining chemicals.