CATALYZED METAL FOIL AND USES THEREOF
20210259112 · 2021-08-19
Inventors
- Shinichi Iketani (Sunnyvale, CA, US)
- Sunity K. Sharma (Fremont, CA, US)
- Gary Lawrence BORGES (San Jose, CA, US)
- Michael Riley Vinson (Sunnyvale, CA, US)
Cpc classification
H05K2203/072
ELECTRICITY
H05K2203/0392
ELECTRICITY
C23C18/1653
CHEMISTRY; METALLURGY
H05K3/4644
ELECTRICITY
H05K2203/0307
ELECTRICITY
C23F17/00
CHEMISTRY; METALLURGY
International classification
H05K3/18
ELECTRICITY
C23C18/16
CHEMISTRY; METALLURGY
C23F17/00
CHEMISTRY; METALLURGY
Abstract
Systems, methods, and devices related to catalyzed metal foils are disclosed. Contemplated metal foils have a bottom surface, preferably roughened to Ra of at least 0.1 μm, bearing a catalyst material. The metal foils are etchable, typically of aluminum or derivative thereof, and is less than 500 μm thick. Methods and systems for forming circuits from catalyzed metal foils are also disclosed. The catalyst material bearing surface of the metal foil is applied to a substrate and laminated, in some embodiments with a thermoset resin or thermoplastic resin therebetween or an organic material first coating the catalytic material. The metal foil is removed to expose the catalyst material, and a conductor is plated to the catalyst material.
Claims
1. A method of forming an electrical circuit using a metal foil having a surface bearing a catalyst material, the method comprising: applying the surface of the metal foil bearing the catalyst material to a surface of a substrate; laminating the metal foil to the substrate; etching the metal foil, thereby exposing the catalyst material; and electroless metal plating a first conductor to the exposed catalyst material; wherein the metal foil is removable.
2. The method of claim 1, wherein the catalyst precursor is reduced to a catalyst either before the step of applying the surface of the metal foil to the surface of the substrate or after the step of etching the metal foil.
3. The method of claim 1, further comprising at least one of the steps of: (i) applying a plating resist in a negative circuit pattern onto the exposed catalyst material before the step of electroless metal plating and removing the plating resist after the step of electroless metal plating; (ii) before the step of electroless metal plating applying an etching resist in a positive circuit pattern onto the exposed catalyst material, etching catalyst material not covered by the etching resist, and removing the etching resist; (iii) applying a plating resist over the first conductor in a negative circuit pattern, electrolytically depositing a second conductor to exposed portions of the first conductor, removing the plating resist, and removing portions of the first conductor not covered by the second conductor; (iv) applying a permanent plating resist in a negative circuit pattern onto the exposed catalyst material, before the step of electroless metal plating.
4. The method of claim 1, further comprising the following steps, after the step of electroless plating: electrolytically depositing a second conductor to the first conductor; applying an etching resist over the second conductor in a positive circuit pattern; etching the first and second conductor not covered by the etching resist; and removing the etching resist.
5. The method of claim 1, wherein the metal foil is selected from the group consisting of aluminum, anodized aluminum, copper, tin, and alloys thereof.
6. The method of claim 1, further comprising one of the steps of (i) applying an adhesive layer between the surface of the metal foil bearing the catalyst material and the surface of the substrate or (ii) applying a polymer layer over a surface of the catalyst material, binding the polymer layer with the substrate, and binding a bonding sheet to at least one of a surface of the polymer layer or a surface of the substrate.
7. The method of claim 1, further comprising the step of applying a layer of a pre-ceramic polymer, a ceramic, a composite of metal oxides, a polymer, an oxidized metal particle, a nitride, or a boride over a surface of the catalyst material.
8. The method of claim 6, further comprising the step of applying a metal oxide layer over a surface of the catalyst material before the step of applying the polymer layer.
9. The method of claim 1, further comprising the step of applying a layer of an organic material no more than 1 μm thick to the catalyst material before applying the metal foil to the substrate, wherein the surface of the metal foil is roughened.
10. The method of claim 9, wherein the surface of the metal foil is roughened by etching.
11. The method of claim 10, wherein the organic material is a copolymer comprising an alkaline-reactive polymer and an alkaline-non-reactive polymer and at least one of (i) the copolymer has a functional group with a lone pair electron, (ii) the functional group comprises one of nitrogen or sulfur, (iii) the alkaline-reactive polymer comprises at least one of a polyimide, an amide, an ester, or a thioester, or (iv) the ratio of the alkaline-reactive polymer to the alkaline-non-reactive polymer is between 5%:95% and 95%:5% by molecular weight, respectively.
12. The method of claim 9, wherein the organic material is selected to (i) protect the catalyst material layer from diffusion of the catalyst material, (ii) improve bonding strength of the catalyst material to a substrate, or (iii) absorb mechanical stress between the catalyst layer and a substrate due to temperature change.
13. A method of producing a metal foil comprising: coating a portion of the metal foil with a catalyst ink, wherein the catalyst ink includes a precursor dissolved in a solvent; drying the catalyst ink coating; and reducing the catalyst precursor to deposit a catalyst on the portion of the metal foil, wherein the metal foil is removable.
14. The method of claim 13, wherein at least one of (i) the metal foil is selected from the group consisting of aluminum, anodized aluminum, copper, tin, and alloys thereof, (ii) the portion of the metal foil is oxidized, (iii) the metal foil is less than 500 μm thick, or (iv) the portion of the metal foil has an Ra of at least 0.1 μm.
15. The method of claim 13, further comprising at least one of the steps of (i) applying a polymer layer over a surface of the dry catalyst ink coating or over a surface of the catalyst, (ii) applying a metal oxide layer over a surface of the catalyst or over a surface of the polymer layer, (iii) applying an organic material no more than 1 μm thick to the catalyst, wherein the portion of the metal foil is roughened.
16. The method of claim 15, wherein the organic material is a copolymer comprising an alkaline-reactive polymer and an alkaline-non-reactive polymer and at least one of (i) the copolymer has a functional group with a lone pair electron, (ii) the functional group comprises one of nitrogen or sulfur, (iii) the alkaline-reactive polymer comprises at least one of a polyimide, an amide, an ester, or a thioester, or (iv) the ratio of the alkaline-reactive polymer to the alkaline-non-reactive polymer is between 5%:95% and 95%:5% by molecular weight, respectively.
17. A method of forming an electrical circuit using a metal foil having a surface bearing a catalyst material, the method comprising: depositing a coating layer to the surface of the metal foil bearing the catalyst material; applying the surface of the metal foil bearing the catalyst material and the coating layer to a surface of a substrate; laminating the metal foil to the substrate; etching the metal foil, thereby exposing the catalyst material; and electroless metal plating a first conductor to the exposed catalyst material; wherein the metal foil is removable.
18. The method of claim 17, wherein the catalyst precursor is reduced to a catalyst either before the step of applying the surface of the metal foil to the surface of the substrate or after the step of etching the metal foil.
19. The method of claim 17, wherein at least one of (i) the metal foil is selected from the group consisting of aluminum, anodized aluminum, copper, tin, and alloys thereof. (ii) the coating layer comprises a polymer, (iii) the coating layer is no more than 500 μm thick, or (iv) the coating layer comprises a pre-ceramic polymer, a ceramic or a composite of metal oxide, polymer, oxidized metal particle, nitride, or boride.
20. The method of claim 17, further comprising at least one of the steps of (i) applying an adhesive layer between the surface of the metal foil bearing the catalyst material to the surface of the substrate, (ii) coating the coating layer with a polymer layer.
21. The method of claim 17, wherein the step of laminating the metal foil to the substrate comprises laminating the coating layer to a bonding sheet.
22. The method of claim 17, wherein the coating layer comprises an organic material no more than 1 μm thick, wherein the surface of the metal foil is roughened, and at least one of (i) the surface of the metal foil is roughened by etching, (ii) the organic material is a copolymer comprising an alkaline-reactive polymer and an alkaline-non-reactive polymer, (iii) the copolymer has a functional group with a lone pair electron, (iv) the functional group comprises one of nitrogen or sulfur, (v) the alkaline-reactive polymer comprises at least one of a polyimide, an amide, an ester, or a thioester, or (vi) the ratio of the alkaline-reactive polymer to the alkaline-non-reactive polymer is between 5%:95% and 95%:5% by molecular weight, respectively.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0023]
[0024]
[0025]
[0026]
[0027]
[0028]
[0029]
[0030]
[0031]
[0032]
[0033]
[0034]
[0035]
[0036]
[0037]
[0038]
DETAILED DESCRIPTION
[0039] 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.
[0040]
[0041]
[0042]
[0043]
[0044]
[0045] 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
[0046]
[0047] 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
[0048]
[0049] 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
[0050]
[0051] 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
[0052]
[0053] 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
[0054]
[0055] While
[0056] 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
[0057]
[0058] 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.
[0059] 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.
[0060] While
[0061]
[0062] 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 μm, 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.
[0063] 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.
[0064] 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.
[0065] While
[0066] 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.
[0067] 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.
[0068] 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.
[0069] 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.
[0070] 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.
[0071] 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.
[0072] 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.
[0073] 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.