Patent Application
20210259115
The field of the invention relates to methods and systems for manufacturing conductive patterns.
The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
As competition in manufacturing electric circuits continues to drive profit margins down, improvements must be made in the simplicity, efficiency, and cost effectiveness of manufacturing protocols in order to maintain a competitive edge in the market. For example, U.S. Pat. No. 4,006,047 to Brummett et al (“Brummett”) teaches using a mylar film soaked in an electroless plating catalyst solution to thermally transfer the catalyst onto a substrate for electroless deposition. However, shipping pre-soaked mylar films creates issues of the mylar material decomposing over time and further shelf-stable, shipping, and durability issues. Also mylar has low melting and decomposition temperature and it does not withstand the original shape under 150° C. or higher temperature. This limits this material and technique usage for the thermoplastic materials which usually have cure temperature of 150° C. or higher. Further, requiring a user to soak the mylar in catalyst solution is unnecessarily complicated, limiting the market user base for the product.
All publications identified herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
Partially addressing durability, U.S. Pat. No. 7,740,936 to Ogawa et al (“Ogawa”) teaches applying nuclei of electroless plating catalyst to a metal foil, which improves durability of the product. However, Ogawa does not teach using such foils to transfer catalyst to substrates for plating, for example using the metal foil as a sacrificial transfer medium.
Thus, there is still a need for improved methods and systems and devices for simply, efficiently, and cheaply patterning catalyst onto substrates to form electric circuits, and methods of manufacturing such circuits therefrom.
The inventive subject matter provides systems, methods, and devices related to catalyzed metal foils, as well as uses thereof and devices therefrom. A metal foil has a bottom surface with a catalyst material disposed on at least part of the bottom surface of the metal foil, with that part of the bottom surface typically roughened, for example via etching or dendrite growth, or in some embodiments oxidized, or combinations thereof. The metal foil is etchable or otherwise removable, and is preferably one of aluminum, anodized aluminum, copper, tin, or alloys thereof. The metal foil is preferably less than 500 μm thick, for example less than 400 m, 300 m, 200 m, 100 m, 80 μm, 60 μm, 50 μm, or less than 10 μm thick. In some embodiments, a part of the bottom surface (e.g., the roughened by dendrite growth portion, roughened by etching portion, etc.) has an arithmetic average roughness (Ra) of at least 0.1 m, 0.15 m, 0.2 m, 0.25 m, 0.3 m, 0.35 m, 0.4 m, 0.45 m, or at least 0.5 μm.
The catalyst material includes a catalyst precursor for at least one of Ag, Au, Pt, Pd, Cu, Ni, Co or Rh in some embodiments. Alternatively, or in combination, the catalyst material includes at least one of catalytic Ag, Au, Pt, Pd, Cu, Ni, Co or Rh. The catalytic material is typically disposed as an ink utilizing an organometal precursor such as organometal compound (e.g., as metal ink, reduced metal ink, thermally reduced metal ink, etc.) as a layer with a thickness of between the atomic radius of a component of the catalytic material (e.g., catalytic metal, Ag, Au, Pt, Pd, Cu, Ni Co or Rh, etc.) and 500 m. The organometal compound can be stabilized by chelating or interacting of counter anions. Alternatively, or in combination, the catalytic material is disposed (e.g., metal ink, reduced metal ink, chemically reduced metal ink, etc.) as a plurality of particles with an average radius of between the atomic radius of a component of the catalytic material (e.g., catalytic metal, Ag, Au, Pt, Pd, Cu, Ni, Co, or Rh, etc.) and 100 nm. In some embodiments, the ink includes some metal particles (of one or more metals) that provide for relatively thicker applications of ink or catalyst precursor, for example by avoiding unstable catalyst precursor conditions due to high concentration of precursor in the ink.
The catalyst layer may also be deposited by sputtering, by evaporation, or chemical vapor deposition.
The inventive subject matter further contemplates systems and methods of forming electrical circuits, as well as circuits formed therefrom. Methods of forming an electrical circuit are contemplated using a metal foil with a surface having a catalyst material. The surface of the metal foil with the catalyst material is applied to a surface of a substrate, and the metal foil is laminated to the substrate. The metal foil (preferably etchable or removable metal foil) is then removed (e.g., etched, etc.), exposing the catalyst material on the surface of the substrate. A first conductor is then electroless metal plated to the exposed catalyst material. Further conductors can be plated (e.g., electrolytic plating) and additional metal foils can be laminated to the conductors and etched as required by an electrical circuit pattern. Metal foils including such layers, and as described below, are of the inventive subject matter.
In some embodiments, the surface of the metal foil with the catalyst material is coated by a coating layer of either a B-stage (curable) thermoset resin (e.g., epoxy resin, polyimide precursor, urethane resin, acrylic resin) or a thermoplastic material, or a combination thereof, which is referred to herein as Resin Coated Catalyzed Foil (RCCF™). In some embodiments, the coating layer is a laminate material (e.g., conventional resins used for laminate such as epoxy resin for FR4, conventional resins used for resin coated foils (RCF) such as R-FR10 (Panasonic) and conventional resins used for bonding film such as ABF (Ajinomoto fine techno)) The resin coated metal foil is then laminated to the substrate, with the coating layer adjacent to the substrate. The metal foil (preferably etchable or removable metal foil) is then removed (e.g., etched, etc.), exposing the catalyst material on the surface of the coating layer (e.g., where coating layer is B-stage resin, lamination cures it to C-stage resin, etc.). A first conductor is then electroless metal plated to the exposed catalyst material. Further conductors can be plated (e.g., via electrolytic plating) and additional metal foils can be laminated to the conductors and etched as required by an electrical circuit pattern.
In some embodiments, the catalyst material is (i) a catalyst precursor for at least one of Ag, Au, Pt, Pd, Cu, Ni, Co, or Rh, or (ii) at least one of catalytic Ag, Au, Pt, Pd, Cu, Ni, Co, or Rh, or combinations thereof. In some methods using a catalyst precursor, the catalyst precursor is reduced (e.g., thermal reduction, chemical reduction, etc.) to a catalyst before the step of applying the surface of the metal foil to the surface of the substrate, in some embodiments after the metal foil has been etched. The metal foil is typically made of one of aluminum, anodized aluminum, copper, tin, and alloys thereof. In some embodiments, an adhesive layer is applied between the surface of the metal foil having the catalyst material to the surface of the substrate.
In some embodiments a pre-ceramic polymer, a ceramic or a composite of metal oxides, polymers or oxidized metal particles, nitrides borides, etc., is coated on a surface the metal foil or on a surface of the catalyst layer, or both. A coating layer can further coat the layer deposited on the catalyst material, not to exceed 500 μm, 100 μm, 10 μm, or 1 μm thick. The thickness depends on the coating material.
A layer of an organic material can further be disposed on the catalyst material layer no more than 10 μm, 5 μm, 1 μm, 0.5 μm, or 0.1 μm thick. The catalyst material layer is preferably no more than 500 nm, 100 nm, 50 nm, or 20 nm thick. The organic material is preferably a copolymer with an alkaline-reactive polymer portion and an alkaline-non-reactive polymer portion. In preferred embodiments the copolymer further includes a functional group with a lone pair electron, or otherwise includes at least one of nitrogen or sulfur. Preferred alkaline-reactive polymer portions have at least one polyimide, amide, ester, or thioester. Generally, the copolymer has a composition of alkaline-reactive polymer portion to alkaline-non-reactive polymer portion of between 5%:95% and 95%:5% by molecular weight, respectively.
The organic material is preferably selected to protect the catalyst material from diffusion of the catalyst material (e.g., during thermal process, lamination, etc.), or otherwise displacement or damage to the catalyst material or its catalytic activity. In some embodiments the organic material is selected to improve bonding strength of the catalyst material to a substrate or absorb mechanical stress between the catalyst layer and a substrate due to temperature change. The organic material is selected to have at least 25%, 50%, 75%, or 100% greater adhesion (e.g., mechanical, chemical, dispersive, diffusive, electrostatic, etc.) to a substrate than the catalyst material has to the substrate.
Methods can further include a step of applying a plating resist in a negative circuit pattern onto the exposed catalyst material before the step of electroless metal plating. The plating resist is then preferably removed (e.g., etched, etc.) after the step of electroless metal plating. It is also contemplated that, before the step of electroless metal plating, an etching resist is applied in a positive circuit pattern onto the exposed catalyst material. The catalyst material not covered by the etching resist is then removed (e.g., etched, etc.), with the etching resist preferably removed thereafter. In some embodiments, a plating resist is further applied over the first conductor in a negative circuit pattern, and a second conductor is electrolytically deposited to exposed portions of the first conductor. The plating resist is preferably removed, and portions of the first conductor not covered by the second conductor are further removed.
In some embodiments, a permanent plating resist is further applied in a negative circuit pattern onto the exposed catalyst material, before the step of electroless metal plating. After electroless plating, it is contemplated that a second conductor is electrolytically deposited to the first conductor, and an etching resist is applied over the second conductor in a positive circuit pattern. The first and second conductor not covered by the etching resist are preferably removed, as is the etching resist.
In some embodiments, a metal is plated to a surface of the substrate. An etching resist layer is further applied in a pattern of a circuit, or at least part of the pattern of a circuit, onto the metal plated surface. The metal not covered by the etching resist layer is etched from the surface. The etching resist is then removed from the surface, leaving plated metal in the shape of the pattern or part of the pattern.
Systems and methods for producing a metal foil are further contemplated. A portion of a metal foil is coated with a catalyst ink, with the catalyst ink coating having a precursor dissolved in a solvent. The catalyst ink coating is then dried on the metal foil, followed by reducing (e.g., thermal reduction, chemical reduction, etc.) the catalyst precursor to deposit a catalyst (e.g., active, etc.) on the portion of the metal foil, which is preferably etchable or otherwise removable. The metal foil is typically one of aluminum, anodized aluminum, copper, tin, or alloys thereof, and is preferably less than 500 μm thick, for example less than 200 m, 100 m, 80 μm, 50 μm, 30 μm, 20 μm, or less than 10 μm thick. In some embodiments, the portion of the metal foil coated by catalyst ink is roughened, for example by etching or dendrite growth, or oxidized, or combinations thereof. Alternatively or in combination, that portion of the metal foil has an Ra of at least 0.1 m, 0.15 m, 0.2 m, 0.25 m, 0.3 m, 0.35 m, 0.4 m, 0.45 m, or at least 0.5 μm. In some embodiments the precursor ink includes metal particles, or one or more metals.
The catalyst is typically at least one of Ag, Au, Pt, Pd, Cu, Ni, Co, or Rh, and is optionally disposed as a layer with a thickness of between the atomic radius of a component of the catalyst (e.g., catalytic metal, Ag, Au, Pt, Pd, Cu, Ni, Co, or Rh, etc.) and 500 m. Alternatively or in combination, the catalyst is disposed as a plurality of particles with an average radius of between the atomic radius of a component of the catalyst and 100 nm. The catalyst ink is typically coated to the metal foil by at least one of dip coating, roller coating, spray coating, spinner coating, bar coating, curtain coating, blade coating, air knife coating, cast coating, screen printing, gravure printing, offset printing, flexography printing, inkjet printing or combinations thereof. In some embodiments, the portion of the metal foil coated by metal ink is one complete surface (e.g., one complete side) of the metal foil.
Methods of forming electrical circuits with a substrate using a metal foil are contemplated. A film is laminated to a surface of the substrate, and a surface of the metal foil is laminated to the film. The metal foil is removed to expose a portion of the film or substrate, and a conductor is deposited on the portion of the film or substrate.
The film is preferably partially or fully cured, for example partially or fully cured before the step of removing the metal foil, after the step of laminating the film to the substrate, or after the step of laminating the metal foil to the film. The film is typically a bonding film, for example one of a B-stage resin sheet, a reinforced B-stage resin sheet, or a prepreg
In some embodiments the film or substrate (or metal foil) is treated with a chemical, either before and separate from the above method or as a step in the method, for example before removing the metal foil, after laminating the film to the substrate, before or after laminating the metal foil to the film, or after removing the foil. The chemical used for treating the film or the substrate is typically one or more of an oxidizer such as a solution of permanganate salts (potassium permanganate, sodium permanganate, etc.) or the like, and alkali metal or alkali earth metal hydroxides (lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, etc.). It is also contemplated that a dry chemical treatment can be used, such as a plasma treatment, a corona discharge treatment, or an electron beam treatment, applied for example as simultaneous treatment, sequential treatment, or combinations thereof.
Further steps include applying a catalyst precursor to the film or substrate and activating the catalyst precursor to a catalyst before the step of depositing the conductor to the portion of the film or substrate. In some embodiments the surface of the metal foil bears a catalyst or a catalyst precursor. Preferably the surface of the metal foil carries a catalyst or a catalyst precursor (whether activated or not) before the step of laminating the surface of the metal foil to the film. The catalyst or catalyst precursor (whether activated or not) remains on the film or substrate after the step of removing the metal foil in preferred embodiments. Typically the catalyst precursor is activated before depositing the conductor, whether before laminating to the film, after chemical treatment, or after removing the metal foil.
Where a catalyst or activated catalyst precursor is used, the conductor is deposited by electroless deposition to the catalyst (or activated precursor). As a further step, another (e.g., different, same, etc.) conductor is electrolytically deposited (e.g., flash deposition) to the first conductor.
Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
The inventive subject matter provides systems, methods, and devices related to catalyzed metal foils, as well as using such foils to form electrical circuits and the circuits formed therefrom.
In some embodiments, catalyzed metal foil 200A can be used in place of catalyzed metal foil 310, for example including optional layer 230A or further optional layer 240 as described. In such embodiments, partial circuit 460A will appear as partial circuit 460B including optional layer 230A as depicted in
In some embodiments, catalyzed metal foil 200A can be used in place of catalyzed metal foil 310, for example including optional layer 230A or further optional layer 240 as described. In such embodiments, partial circuit 580 will appear as partial circuit 460B including optional layer 230A as depicted in
In some embodiments, catalyzed metal foil 200A can be used in place of catalyzed metal foil 310, for example including optional layer 230A or further optional layer 240 as described. In such embodiments, partial circuit 680 will appear as partial circuit 460B including optional layer 230A as depicted in
In some embodiments, catalyzed metal foil 200A can be used in place of catalyzed metal foil 310, for example including optional layer 230A or further optional layer 240 as described. In such embodiments, partial circuit 750A will appear as partial circuit 750B including optional layer 230A as depicted in
In some embodiments, catalyzed metal foil 200A can be used in place of catalyzed metal foil 310, for example including optional layer 230A or further optional layer 240 as described. In such embodiments, partial circuit 880 will appear as partial circuit 460B including optional layer 230A as depicted in
While
In some embodiments, catalyzed metal foil 200A can be used in place of catalyzed metal foil 310, for example including optional layer 230A or further optional layer 240 as described. In such embodiments, catalyzed substrate 970A will appear as catalyzed substrate 970B including optional layer 230A as depicted in
Interim material 1020 includes removeable metal 1012, catalyst layer 1014, and polymer layer 1016, further including bonding sheet 1022 and substrate 1024. As noted, the contents of polymer layer 1016 are preferably selected to maintain strong binding or adhesion between catalyst layer 1014 and a surface of bonding sheet 1022. Likewise, bonding sheet 1022 is selected to maintain strong binding or adhesion between bonding sheet 1022 and a surface of substrate 1024. In some embodiments, polymer layer 1016 is selected to maintain strong binding or adhesion to a broad class of bonding sheets, bonding sheet 1022 is selected to maintain strong binding or adhesion to a broad class of substrates, or both.
Interim material 1030 includes removeable metal 1012, catalyst layer 1014, polymer layer 1016, bonding sheet 1022, and substrate 1024 adhered or bonded together as depicted (e.g., laminated). Finished material results from removing etchable metal 1012 and exposing a surface of catalyst layer 1014. It is contemplated that finished material 1040 can be further processed to, for example, plate a conductor (electroless, electrolytic, various combinations thereof, etc.) to finished material 1040, in a pattern, in bulk, or both. Such methods are useful for adding electrical transmission lines, circuit patterns, new or improved RF properties or capabilities, or the like to substrate 1024 or finished material 1040A, for example when substrate 1024 already includes electrical circuits or various electronic components with rated, approved, or certified performance tolerances or characteristics.
While
Interim material 1120 further includes polymer layer 1118, which is deposited on a surface of metal oxide layer 1116. Preferably, content of polymer layer 1118 is specifically selected, designed, or formulated to bind or adhere favorably to catalyst layer 1116, to a surface of bonding sheet 1122 (e.g., prepreg, bonding film, adhesive sheet), to metal oxide layer 1116, or combinations thereof. For example, polymer layer 1118 can include a single polymer variant with high strength or binding specificity to bonding sheet 1122, can include a number of polymer variants with desirable binding or adherence traits, physical tolerance (temperature tolerances, flexibility, durability, etc.), or electrical traits (e.g., EM insulation, conductivity, resistivity, dielectric, etc.), or otherwise doped with other materials to imbue polymer layer 1118 with such desirable properties. Further, in preferred embodiments the combined thickness of metal oxide layer 1116 and polymer layer 1118 is between 1.0 μm and 0.01 m, but where practical or favorable can be less than 500 nm, less than 100 nm, or less than 50 nm. Reducing the separation between catalyst layer 1114 and bonding sheet 1122, or moreover between catalyst layer 1114 and substrate 1124, is absolutely critical in some embodiments.
Interim material 1130 includes removeable metal 1112, catalyst layer 1114, metal oxide layer 1116, and polymer layer 1118, further including bonding sheet 1122 and substrate 1124. As noted, the contents of polymer layer 1118 are preferably selected to maintain strong binding or adhesion between metal oxide layer 1116 (thereby catalyst layer 1114 and removable metal 1112) and a surface of bonding sheet 1122. Likewise, bonding sheet 1122 is selected to maintain strong binding or adhesion between bonding sheet 1122 and a surface of substrate 1124. In some embodiments, polymer layer 1118 is selected to maintain strong binding or adhesion to a broad class of bonding sheets, bonding sheet 1122 is selected to maintain strong binding or adhesion to a broad class of substrates, or both.
Interim material 1140 includes removeable metal 1112, catalyst layer 1114, metal oxide layer 1116, polymer layer 1118, bonding sheet 1122, and substrate 1124 adhered or bonded together as depicted (e.g., laminated). Finished material 1150 results from removing removeable metal 1112 and exposing a surface of catalyst layer 1114. It is contemplated that finished material 1140 can be further processed to, for example, plate a conductor (electroless, electrolytic, various combinations thereof, etc.) to finished material 1150, in a pattern, in bulk, or both. Such methods are useful for adding electrical transmission lines, circuit patterns, new or improved RF properties or capabilities, or the like to substrate 1124 or finished material 1150, for example when substrate 1124 already includes electrical circuits or various electronic components with rated, approved, or certified performance tolerances or characteristics.
While
In embodiments with a catalyst precursor on the surface of bonding film 1415, the catalyst precursor is activated, and copper 1440 is otherwise electrolessly deposited on the activated catalyst to form finished or interim material 1430. While bonding film 1414 is substantially the same as 1415, in some embodiments bonding film 1415 is partially or fully cured compared to bonding film 1414, or otherwise treated with a chemical. Likewise, laminate 1416 is substantially the same as 1417, though in some embodiments laminate 1417 is further treated with a chemical.
The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
As used herein, and unless the context dictates otherwise, the term “coupled to” is intended to include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). Therefore, the terms “coupled to” and “coupled with” are used synonymously.
In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
Unless the context dictates the contrary, all ranges set forth herein should be interpreted as being inclusive of their endpoints, and open-ended ranges should be interpreted to include only commercially practical values. Similarly, all lists of values should be considered as inclusive of intermediate values unless the context indicates the contrary.
As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.
It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C . . . and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.
This application claims the benefit of priority to U.S. patent application Ser. No. 17/174,759 filed Feb. 12, 2021, which in turn claims the benefit of priority to U.S. Provisional Patent No. 63/119,950 filed Dec. 1, 2020, which in turn claims the benefit of priority to U.S. Provisional Patent No. 63/066,508 filed Aug. 17, 2020, which in turn claims the benefit of priority to U.S. Provisional Patent No. 62/976,110, filed Feb. 13, 2020, each of which is incorporated by reference in its entirety herein.
| Number | Date | Country | |
|---|---|---|---|
| 62976110 | Feb 2020 | US | |
| 63066508 | Aug 2020 | US | |
| 63119950 | Dec 2020 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17174759 | Feb 2021 | US |
| Child | 17208890 | US |
