JP2015128175A - Method of processing copper surface to enhance adhesion to organic substrate for use in printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed circuit board (PCB) or a printed wiring board (PWB) obtained by processing a smooth copper surface so as to enhance adhesion between the copper surface and an organic substrate.SOLUTION: A copper oxide layer includes a plurality of particles having the size of approximately 250 nm or less; the particles are oriented in a substantially irregular manner; and the copper oxide layer has the surface having roughness of approximately 0.14 μm Ra or less. A printed circuit board includes at least one copper layer, at least one polymer material layer, and a stabilization layer between the copper layer and the polymer material layer; the stabilization layer includes a plurality of particles having the size of approximately 250 nm or less; and the particles are oriented in a substantially irregular manner.

Description

  Embodiments of the present invention relate to the manufacture of printed wiring boards (PCBs) or printed wiring boards (PWBs), collectively referred to as PCBs, and in particular for treating copper surfaces and used for copper surfaces and PCBs. The present invention relates to a method for increasing the adhesion between an organic substrate. In some embodiments of the present invention, a method is provided that achieves improved bond strength without roughening the smooth copper surface topography. The copper surface obtained by this method provides a strong bond to the resin layer. The bonded interface between the treated copper and the PCB resin layer exhibits resistance to heat, humidity, and chemicals included after the lamination process steps.

  The miniaturization, portability, and ever-increasing features of consumer electronics are driving printed wiring board manufacturing towards smaller, more densely packed boards. Increasing number of interconnect layers, decreasing core and stack thickness, decreasing copper interconnect width and spacing, smaller diameter through holes, and microvias are key to high density interconnect (HDI) packages or multilayer PCBs Some of the characteristics.

  The copper wiring that forms the PCB wiring layout is typically manufactured by either a subtractive process, an additive process, or a combination of these processes. In the subtractive process, a desired circuit pattern is formed by etching downward from a thin copper foil laminated to a dielectric substrate, where the copper foil is covered with a photoresist and the latent image of the desired circuit is formed. Is formed in the resist after the exposure, the areas of the resist where no circuitry is present are washed away in the resist developer, and the underlying copper is etched by the etchant. In the additive process, the copper pattern is stacked up from the bare dielectric substrate in the channel of the circuit pattern formed by the photoresist. Additional copper circuit layers, often referred to as “prepregs”, are joined by partially cured dielectric resin, alternating copper wiring conductor layers and dielectric resin insulation layers A multilayer assembly is formed. This assembly is then subjected to heat and pressure, thereby curing the partially cured resin. The through holes are drilled and plated with copper to electrically connect all circuit layers, thus forming a multilayer PCB. The manufacturing process of multilayer PCB is well known and described in many publications, for example, Non-Patent Document 1 and Non-Patent Document 2. Regardless of the PCB structure and manufacturing method, it is essential to achieve good adhesion between the copper circuit layer and the resin insulation layer. A circuit board consisting of insufficient adhesion cannot withstand the high temperatures of solder reflow and subsequent soldering, resulting in delamination of the board and electrical malfunction.

  The patterned copper surface is smooth, but this smooth surface does not adhere well to the resin layer. It is theoretically known that increasing the contact area between two different materials increases the bond strength. To improve the bond between copper and resin, the most standard method is to create a very rough copper surface, increasing its surface area and acting as a mechanical bond anchor that promotes adhesion to the resin. Rely on the introduction of undulating peaks and valleys on the surface.

  One of the most widely known and most commonly used methods is the so-called “black oxide process”, in which a black oxide layer with a rough surface is formed on the top surface of the copper surface. . The black oxide consists of needle-like dendritic crystals or whiskers of a mixture of cuprous oxide and copper oxide up to 5 microns in length. This large crystal structure provides a large surface area and mechanical anchoring effect, thus providing good bondability. U.S. Patent Nos. 5,099,086, and 5,099,9, by Meyer, first disclose the oxidation of a copper surface to a black oxide layer using an alkaline chlorite solution. Some typical disclosures of early work applying this method to copper-resin bonding in PCBs are as follows: US Pat. Including.

  Such acicular oxide layers greatly increase surface area and bondability, but dendritic crystals are brittle and easily damaged during the lamination process, resulting in bond failure within the oxide layer. Subsequent variations to the oxidation process focused on improving the mechanical stability by reducing the crystal size, and thus the thickness of the oxide layer, and optimizing the chemical concentration and other process parameters. . Some notable improvements in this regard are shown by U.S. Pat. Nos. 5,047,086 and 5,047,11, in which alkaline chlorite solutions at specific concentration levels and the ratio of hydroxide to chlorite are reported. A prescription is disclosed. U.S. Patent No. 6,057,031 discloses the addition of a water soluble or dispersible polymer additive to an alkaline chlorous acid solution to produce a black oxide coating with reduced thickness and high uniformity. Patent Document 13 discloses a method for promoting rapid generation of copper oxide by pretreating a copper surface with a sulfaoxyacid reducing agent. Other methods for forming black oxide are disclosed in hydrogen peroxide solution as disclosed in Patent Document 14, alkaline permanganate as disclosed in Patent Document 15, and Patent Document 16. And oxidation of the copper surface with a dichromate solution as disclosed in US Pat.

  One remaining problem associated with this oxide roughening method is that copper oxide is soluble in acid and severe debonding of the joint interface occurs during subsequent process steps including the use of acid. It is. For example, as described above, through holes are drilled through the multilayer board and plated with copper to provide circuit layer interconnections. Resin smears are often formed on the surface of the pores by drilling and must be removed by a desmear process involving acid neutralization followed by permanganate etching. The acid dissolves the copper oxide from the surface of the hole to a few millimeters inward, as evidenced by the formation of a pink ring around the through hole due to the pink color of the underlying copper. The formation of the pink ring corresponds to local delamination and indicates a serious defect in the PCB. These defects have become a major obstacle in the production of multilayer PCBs, and extensive efforts have been made to seek further improvements in the oxide layer so that the oxide layer is not susceptible to acid attack and such local delamination. .

  Methods to solve the pink ring problem mainly included post-treatment of copper oxide. For example, Patent Document 16 first oxidizes a copper surface to form an oxide layer, and then treats the oxide layer with phosphoric acid to form a glass-like film of copper phosphate, resulting in high bonding strength and acid resistance. Is disclosed. U.S. Patent No. 6,057,032 discloses a process for improving the acid resistance of copper oxide by contacting the copper oxide with a solution containing an amphoteric element that forms an acidic oxide such as selenium dioxide. U.S. Patent No. 6,057,031 discloses a process in which a copper oxide layer is first formed and then treated with chromic acid to stabilize the copper oxide and / or protect the copper oxide from dissolution in acid. .

Many studies have shown that acid resistance is improved by first forming copper oxide on the surface of the copper and then reducing the copper oxide to a cuprous oxide or copper-rich surface. Patent Document 20 discloses a method of reducing copper oxide using a borane reducing agent represented by the general formula BH ₃ NHRR ′, where R and R ′ are H, CH ₃ and CH ₂ CH, respectively. Selected from the group consisting of _three . Patent Document 21 discloses a reducing agent selected from the group consisting of diamine (N ₂ H ₄ ), formaldehyde (HCHO), sodium thiosulfate (Na ₂ S ₂ O ₃ ), and sodium borohydride (NaBH ₄ ). Disclosure. Patent Document 22, Patent Document 23, Patent Document 24, and Patent Document 25 disclose reducing agents composed of cyclic borane compounds such as morpholine borane, pyridine borane, piperidine borane and the like. The most commonly practiced method of reducing copper oxide to form cuprous oxide is by use of a dimethylamine borane (DMAB) reducing agent. This method has reduced the pink ring radius to a certain extent, but is still limited and does not completely solve the problem because cuprous oxide is not completely insoluble in acid. It was.

  In order to solve the above-described problems, Patent Document 26 and Patent Document 27 disclose a method of reducing copper oxide to copper while maintaining the needle-like structure of the oxide. However, such needle-like structures are mechanically unstable and are crushed during the lamination process. Alternative oxide coating processes were subsequently developed. Some exemplary processes are disclosed in US Pat. These alternative processes produce a highly roughened copper surface by combining a conventional oxidation process with a controlled etch that simultaneously roughens the underlying copper surface while oxidizing the copper surface. In many cases, the organic layer is simultaneously coated to act as a corrosion inhibitor or adhesion promoter. U.S. Patent No. 6,057,031 discloses a micro-roughening process using an etchant with a corrosion inhibitor such as hydrogen peroxide, inorganic acid, and triazole. Patent Literature 35, Patent Literature 29, Patent Literature 36, Patent Literature 37, and Patent Literature 38 use a composition comprising an oxidizing agent, a pH adjuster, a topography modifier, a uniformity enhancer, and an azole deterrent. A similar method for providing a simplified copper surface is disclosed. For the same purpose, Patent Literature 28, Patent Literature 39, Patent Literature 30, Patent Literature 40, Patent Literature 41, Patent Literature 42, and Patent Literature 31 include an oxidizing agent such as hydrogen peroxide, a copper oxide ion source, A microetch composition comprising an organic acid, a halide ion source, and an azole type inhibitor is disclosed. Although these methods have increased acid resistance, interfacial bonding is achieved primarily by mechanical anchors, and adhesive strength decreases rapidly as the surface roughness of the treated copper surface decreases.

  As can be readily appreciated, many methods have been developed to improve the adhesion between the copper surface and the dielectric resin used in the PCB, but these methods produce a very rough surface, It relied on promoting adhesion thereby. It is a universal idea in the prior art that the copper surface must be roughened in order to increase the surface area for bonding or bonding to the epoxy or dielectric resin. However, this method is limited because the width and / or spacing of the copper wiring is limited, thus preventing further miniaturization of the PCB circuit. The current trend towards high density PCBs with finer wiring circuits and increasing number of layers has created a need for higher bond strength of copper to dielectric resin while maintaining a smooth surface. Clearly, there is a need for further development and development of PCBs such as, but not limited to, copper surface treatment processes that increase bond strength but do not roughen the copper surface.

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“Printed Circuits Handbook” Sixth Edition, Edited by C.I. F. Coombs, Jr. McGraw-Hill Professional, 2007 “Printed Circuit Board Materials Handbook” Edited by M.M. W. Jawitz, McGraw-Hill, 1997 “Advanced Inorganic Chemistry”, 5th edition, Cotton & Wilkinson, John Wiley & Sons, 1988, “Organometallics, A Concise Introduction”, Elschenbroich et al., 2nd edition, 1992, 30 VCH. “Comprehensive Organometallic Chemistry II, A Review of the Literature” 1982-1994, edited by Abel et al., Vol. Chapter 7, Chapter 7, Chapter 8, Chapter 10 and Chapter 11, Pergamon Press Robins et al. Am. Chem. Soc. 104: 1882-1893 (1982) Gassman et al. Am. Chem. Soc. 108: 4228-4229 (1986) Connelly et al., Chem. Rev. 96: 877-910 (1996) Geiger et al., Advances in Organometallic Chemistry 23: 1-93 Geiger et al., Advances in Organometallic Chemistry 24:87 Ng and Jiang (1997) Chemical Society Reviews 26: 433-442. Cotton and Wilkenson, Advanced Organic Chemistry, 5th edition, John Wiley & Sons, 1988

  Accordingly, some embodiments of the present invention provide a method of manufacturing a printed wiring board (PCB) by treating a smooth metal surface, thereby increasing the adhesion between the copper surface and the organic substrate. To do. The copper surface treatment process as provided by embodiments of the present invention, which increases the bond strength and does not significantly roughen the copper surface, is completely different and contrary to the prior art. .

  In a further embodiment of the present invention, a method for bonding a smooth copper surface to a resin in a PCB is provided, wherein the bonding interface has desirable resistance to chemicals contained after heat, moisture, and lamination process steps.

  In some embodiments, pre-cleaning a smooth copper surface with an alkaline and / or peroxide solution, stabilizing the surface by forming copper oxide on the copper surface, and reducing Adjusting the oxide layer with an agent and optionally a binding molecule, thereby obtaining the desired morphology, uniformity, and bonding location, and bonding the treated copper surface to the resin, for example by heat and pressure And a method of forming a PCB comprising the steps. In some embodiments, one or more molecules can be bound to the copper oxide layer, the one or more organic molecules being one or more bonds configured to bind to the copper oxide surface. A thermally stable base carrying a binding group and one or more attachment groups configured to attach to the resin is provided.

  In another embodiment, a method of manufacturing a PCB is provided, the method comprising pre-cleaning a copper surface with an alkaline solution and / or a peroxide solution and forming a copper oxide layer on the copper surface. Stabilizing the copper surface, and stopping the formation of the copper oxide layer by a self-limiting reaction between the copper oxide and one or more inhibitory compounds, and Joining the copper surface to the resin. In some embodiments, one or more molecules can be bound to the copper oxide layer, and the one or more organic molecules are one or more bonds configured to bind to the copper oxide surface. A heat-stable substrate having a group and one or more attachment groups configured to attach to the resin.

  The foregoing and other features of the present invention will become apparent in light of the following detailed description taken in conjunction with the accompanying drawings, and like reference numerals refer to like parts throughout.

FIG. 4 illustrates one embodiment of a copper-resin bonding process according to the present invention compared to a conventional roughening process. FIG. 2 illustrates one embodiment of a metal-resin bonding process according to the present invention compared to a conventional roughening process. FIG. 4 is an experimental process flow diagram illustrating one embodiment of the method of the present invention. It is a SEM photograph of the smooth copper surface before a process. 2 is an SEM photograph of a copper surface treated according to an embodiment of the present invention, showing the smoothness of the treated surface. 2 is a SEM photograph of a conventional rough black oxide surface as described in the prior art. 2 is a SEM picture of a micro-roughened copper surface as described in the prior art. It is a figure which compares the surface roughness expressed by both Ra and Rz of the copper surface shown to FIG. FIG. 4 is an Auger depth profile showing that a treated copper layer has a thickness of less than 100 nm in accordance with some embodiments of the present invention. FIG. 6 is a diagram showing an example of a test sample layout used to perform a peel strength test on a copper test strip on an epoxy substrate. FIG. 2 is a simplified cross-sectional view showing test sample preparation and illustrating the lamination process used. FIG. 2 is a simplified cross-sectional view showing test sample preparation and illustrating the lamination process used. FIG. 2 is a simplified cross-sectional view showing test sample preparation and illustrating the lamination process used. FIG. 2 is a simplified cross-sectional view showing test sample preparation and illustrating the lamination process used. FIG. 4 is a diagram illustrating peel strength and surface roughness for a smooth copper surface laminated with epoxy, processed according to an embodiment of the present invention, in comparison with an experimental reference. FIG. 4 is a diagram illustrating peel strength and surface roughness for a smooth copper surface laminated with epoxy, processed according to an embodiment of the present invention, in comparison with an experimental reference. FIG. 3 shows a SEM cross-sectional view of a laminated and treated copper surface formed by an embodiment of the present invention prior to HAST. FIG. 2 is a view showing a SEM cross-section of a laminated and treated copper surface formed by an embodiment of the present invention after HAST, indicating no delamination after HAST. In the smooth copper control, an SEM photograph of the peeled copper surface showing that the copper-resin interface is just breaking at the copper surface. In a smooth treated copper according to one embodiment of the present invention, an SEM photograph of a stripped copper surface showing that the copper-resin interface is broken in the resin. FIG. 3 is an SEM cross-sectional picture of a laser via formed on a laminated, treated smooth copper surface, showing no undercut after desmear process and plating. FIG. 4 shows the peel strength and surface roughness of a smooth copper surface laminated with a solder resist, processed according to an embodiment of the present invention, in comparison with a control substrate. FIG. 4 shows the peel strength and surface roughness of a smooth copper surface laminated with a solder resist, processed according to an embodiment of the present invention, in comparison with a control substrate. It is a photograph of the SR pattern and via array on the copper wiring. It is a photograph of a BGA pattern. FIG. 6 is a cross-sectional SEM photograph of an SR via formed on a laminated and processed copper surface formed according to an embodiment of the present invention, showing that no delamination occurs after the desmear process and plating.

  It is to be understood that both the foregoing general description and the following description are exemplary and explanatory only and are not limited to the methods and apparatus described herein. In this application, the singular forms include the plural unless specifically stated otherwise. Also, the use of “or” means “and / or” unless stated otherwise. Similarly, “comprising”, “including”, and “having” are not intended to be limiting.

  In some embodiments, a method of manufacturing a printed wiring board (PCB) for promoting adhesion or bonding between a copper surface and an organic substrate is provided, the method comprising a copper oxide layer on the copper surface. Stabilizing the copper surface by forming and adjusting the copper oxide layer by reducing the copper oxide with a reducing agent.

  It is particularly advantageous that the copper oxide layer exhibits unique characteristics, which may also be referred to as a stabilization layer. In some embodiments, the conditioned copper oxide layer has a thickness of about 200 nanometers or less. In some embodiments, the copper oxide has a form consisting of a substantially amorphous structure.

  In an exemplary embodiment, the copper oxide layer has grains, and after conditioning, the grains have a size of 250 nanometers or less. In another embodiment, the copper oxide layer has grains, and after conditioning these grains have a size of 200 nanometers or less. In some embodiments, the copper oxide layer has grains, which are substantially randomly oriented after conditioning.

  The copper surface is stabilized by exposing the copper surface to an oxidizing agent. In an exemplary embodiment, the oxidizing agent is selected from one or more of sodium chlorite, hydrogen peroxide, permanganate, perchlorate, persulfate, ozone, or a mixture of these substances. The The step of stabilizing the copper surface can be performed at a temperature ranging from room temperature to about 80 ° C.

After stabilization, the copper oxide layer is adjusted with a reducing agent. In some embodiments, the reducing agent is selected from the group consisting of formaldehyde, sodium thiosulfate, sodium borohydride, the general formula BH ₃ NHRR ′ (R and R ′ are each H, CH ₃ , CH ₂ CH _3. Selected from one or more of borane reducing agents such as dimethylamine borane (DMAB), cyclic boranes such as morpholine borane, pyridium borane, piperidine borane.

  Particularly advantageously, embodiments of the present invention provide a method for manufacturing a PCB from a “smooth” copper substrate, ie, a copper substrate that has not been previously roughened. For example, suitable copper substrates for use in the method of the present invention include, but are not limited to, electrolytic copper or electroplated copper, electroless plated copper, and rolled copper, and prepare these copper substrates. It is not limited by the method.

  In some embodiments, the copper substrate or surface has a roughness of about 0.13 μm Ra. In some embodiments, the copper oxide, or treated smooth copper surface or also referred to as the stabilization layer, has a roughness of 0.14 μm Ra or less.

  In another aspect, the present invention provides a method of manufacturing a printed wiring board, the method comprising pre-cleaning a copper surface with an alkaline solution and / or a peroxide solution and forming the copper oxide thereon Thereby stabilizing the copper surface, adjusting the copper oxide layer with a reducing agent, and bonding the treated copper surface with a resin.

  FIGS. 1A and 1B show one exemplary embodiment consisting of a simplified view of a smooth copper-resin interface 100A comprising a smooth copper surface 102 bonded to a smooth resin substrate 104. FIG. . A dense oxide or organic stabilization layer 106 is formed on the top surface of the copper to protect the copper surface from corrosion or chemical attack that is a major cause of interface failure. In some embodiments, although not required, the stabilization layer 106 is further conditioned or primed with an organic molecular layer to react with the functional group Y in the resin 104 to form a covalent bond. It is desirable to facilitate chemical bonding by forming active binding sites X. In the exemplary embodiment, the smooth copper-resin interface is superior to the roughened copper-resin interface 100B known in the prior art where interfacial bonding is achieved primarily by mechanical anchors. Has adhesive strength and resistance to heat, moisture, and chemical attack.

  Referring to FIG. 2 to further illustrate features of the present invention, an exemplary experimental process flow is shown, which includes four main steps: (1) surface pretreatment 200, (2) surface. Stabilization and adjustment 300, (3) vacuum lamination 400, and (4) heat treatment 500. Specific data and results are shown for illustrative purposes only and are not intended to limit the scope of the invention. FIG. 2 also shows where the peel strength test is performed in the process, but this is shown only to illustrate the test procedure. The broad method steps of the present invention do not include a peel test step.

  In the exemplary method shown in FIG. 2, surface pretreatment is performed by rinsing and drying the substrate in alkaline cleaning 202, rinsing 204, soft etch and pickling 206, and 208.

  The surface is then stabilized by surface oxidation at 302 and rinsed at 304. The surface is then conditioned by reduction at 306 and step 306 can include optional functionalization followed by rinsing and drying of the substrate at 308.

After the conditioning step 306, vacuum lamination is performed by assembly of the laminated film 402 on the stabilized substrate at 402, vacuum lamination at 404, and optionally a vacuum press at 406.

  A heat treatment is then performed to cure or anneal the laminated assembly at 502, which is then subjected to a peel test at 600.

  Also, some embodiments of the present invention carry one or more linking groups configured to bond to a metal surface and one or more attachment groups configured to attach to an organic substrate. The step of adhering the metal surface to one or more organic molecules comprising a thermally stable base is provided. In one exemplary embodiment, the one or more modifying molecules are a surface active molecule (SAM) or a surface active moiety.

  Particularly advantageously, the PCB includes a copper oxide layer, which is sometimes referred to as a stabilization layer, but exhibits unique characteristics. In some embodiments, the conditioned copper oxide layer has a thickness of about 200 nanometers or less. In some embodiments, the copper oxide has a morphology consisting of a substantially amorphous structure.

  In the illustrated embodiment, the copper oxide layer has a highly dispersed grain structure, and after conditioning the grains have a size of 200 nanometers or less. In another embodiment, the copper oxide layer has grains, and after conditioning, the grains have a size of 100 nanometers or less. In some embodiments, the copper oxide has grains, which after orientation are substantially randomly oriented.

  The copper surface is stabilized by exposing the copper surface to an oxidant. In an exemplary embodiment, the oxidant is selected from sodium chlorite, hydrogen peroxide, permanganate, perchlorate, persulfate, any one or more of ozone, or a mixture of these materials. Is done. The step of stabilizing the copper surface is performed at a temperature ranging from room temperature to about 80 ° C. Alternatively, the copper surface can be stabilized by thermal oxidation and electrochemical anodization.

After stabilization, the copper oxide layer can be adjusted with a reducing agent. In some embodiments, the reducing agent is selected from the group consisting of formaldehyde, sodium thiosulfate, sodium borohydride, the general formula BH ₃ NHRR ′ (R and R ′ are each H, CH ₃ , CH ₂ CH _3. Selected from one or more of a borane reducing agent such as dimethylamine borane (DMAB) and a cyclic borane such as morpholine borane, pyridium borane, piperidine borane.

  The copper oxide layer can be adjusted at a temperature ranging from room temperature to about 50 ° C. In some embodiments, the entire method is performed within a time period ranging from about 2 to 20 minutes.

  Also, some embodiments of the present invention include one or more linking groups configured to bond to a copper oxide surface after conditioning and one or more configured to attach to an organic substrate after conditioning. The step of contacting the copper oxide surface with one or more surface active molecules (SAMs) comprising a thermally stable base that retains the attachment group is provided. In exemplary embodiments, the one or more organic surface active molecules are surface active moieties.

  Any suitable surface active molecule or surface active moiety can be used. In some embodiments, a surface modifier moiety is a macrocyclic proligand, a macrocyclic complex, a sandwich coordination complex, and a polymer of a sandwich coordination complex. Selected from the group consisting of Alternatively, the surface modifying compound can comprise porphyrin.

  One or more surface active molecules (SAMs) are: porphyrin, porphyrin macrocycle, extended porphyrin, ring-reduced porphyrin, linear porphyrin polymer, porphyrin sandwich coordination complex, porphyrin sequence, silane, tetraorgano-silane, aminoethyl- Aminopropyl-trimethoxysilane, (3-aminopropyl) trimethoxysilane, (1- [3- (trimethoxysilyl) propyl] urea) ((1- [3- (Trimethoxysilyl) propyl] urea)), (3 -Aminopropyl) triethoxysilane, ((3-glycidyloxypropyl) trimethoxysilane), (3-chloropropyl) trimethoxysilane, (3-glycidyloxypropyl) trimethoxysilane, dimethyldichlorosilane, 3- (trimethylsilane) Xylyl) propyl methacrylate, ethyltriacetoxysilane, triethoxy (isobutyl) silane, triethoxy (octyl) silane, tris (2-methoxyethoxy) (vinyl) silane, chlorotrimethylsilane, methyltrichlorosilane, silicon tetrachloride, tetraethoxysilane, It can be selected from the group of phenyltrimethoxysilane, chlorotriethoxysilane, ethylene-trimethoxysilane, amine, sugar, or any combination of these materials. Alternatively, consisting of molybdate, tungstate, tantalate, niobate, vanadate, or molybdenum, tungsten, tantalum, niobium, vanadium isopoly or heteropoly acids, and combinations of any of the above Inorganic molecules from the group, and combinations of any of the above can be used for the same purpose.

  In some embodiments, the one or more attachment groups consist of an aryl functional group and / or an alkyl attachment group. When the attachment group is aryl, the aryl functional group includes acetate, alkylamino, allyl, amine, amino, bromo, bromomethyl, carbonyl, carboxylate, carboxylic acid, dihydroxyphosphoryl, epoxide, ester, ether, Ethynyl, formyl, hydroxy, hydroxymethyl, iodo, mercapto, mercaptomethyl, Se-acetylseleno, Se-acetylselenomethyl, S-acetylthio, S-acetylthiomethyl, selenyl, 4,4,5,5-tetramethyl- A functional group selected from any one or more of 1,3,2-dioxaborolan-2-yl, 2- (trimethylsilyl) ethynyl, vinyl, and combinations of these groups may be provided.

  When the attachment group consists of alkyl, the alkyl attachment group is acetate, alkylamino, allyl, amine, amino, bromo, bromomethyl, carbonyl, carboxylate, carboxylic acid, dihydroxyphosphoryl, epoxide, ester, ether, ethynyl, formyl. , Hydroxy, hydroxymethyl, iodo, mercapto, mercaptomethyl, Se-acetylseleno, Se-acetylselenomethyl, S-acetylthio, S-acetylthiomethyl, selenyl, 4,4,5,5-tetramethyl-1,3 , 2-dioxaborolan-2-yl, 2- (trimethylsilyl) ethynyl, vinyl, and functional groups selected from any one or more of these groups.

  In an alternative embodiment, at least one attachment group consists of an alcohol or phosphate. In further embodiments, the at least one attachment group is composed of any one or more of amines, alcohols, ethers, nucleophiles, phenylethynes, phenylallylic groups, phosphates, and combinations of these substances. can do.

  In general, in some embodiments, the organic molecule comprises a thermally stable unit or substrate having one or more bond groups X and one or more attachment groups Y. In certain embodiments, the organic molecule is a refractory metal binding molecule and comprises one or more “surface active moieties” referred to as “redox active moieties” or “ReAMs” in related applications. Can do. In general, in some embodiments, there are several beneficial surface active moieties in the present invention, all of which are based on polydentate proligands that include macrocycles and non-macrocycle components. ing. Many suitable proligands and complexes, and suitable substituents are outlined in the references drawn above.

  Suitable proligands include two categories: atoms of nitrogen, oxygen, sulfur, carbon, or phosphorus as coordination atoms (generally referred to in the literature as sigma (a) donors). It is classified into a ligand to be used and an organometallic ligand such as a metallocene ligand.

  A single surface active moiety can also have two or more redox active subunits, using porphyrin and ferrocene.

  In some embodiments, the surface active moiety is a macrocyclic ligand and contains both a macrocyclic proligand and a macrocyclic complex. Here, the “macrocycle proligand” contains a donor atom (sometimes referred to herein as a “complex atom”) that is oriented so that it can bind to a metal ion and surrounds the metal atom. Means a sufficiently large cyclic complex. In general, donor atoms are, but are not limited to, heteroatoms containing nitrogen, oxygen and sulfur, with nitrogen containing heteroatoms being particularly preferred. However, as will be appreciated by those skilled in the art, different metal ions selectively bind to different heteroatoms, and thus the heteroatoms used can depend on the desired metal ion. Further, in some embodiments, a single macrocycle can contain different types of heteroatoms.

  A “macrocyclic complex” is a macrocyclic proligand having at least one metal ion, and in some embodiments the macrocyclic complex comprises a single metal ion, but as described below, a polynuclear macrocycle Multinuclear complexes, including complexes, are also contemplated.

  A wide variety of macrocycle ligands find use in the present invention, including macrocycles that are electrically conjugated and non-electrically conjugated. In some embodiments, linkages, chemical bonds, and substituents are selected so as to yield an electrically conjugated compound and have at least two oxidation states.

  In some embodiments, the macrocycle ligand of the present invention is selected from the group consisting of porphyrins (particularly porphorin derivatives as defined below) and cyclen derivatives. A particularly preferred subset of macrocycles suitable for the present invention includes porphyrins including porphyrin derivatives. Such derivatives are orthofused to porphyrins having a seat nucleus or porphyrins having an excess of orthoperfused chain porphyrins, one or more carbon atoms of the porphyrin chain being exchanged by another element (skeletal exchange) ) Porphyrins, derivatives in which the nitrogen atom of the porphyrin chain is exchanged by another element (nitrogen skeleton exchange), meso-, 3-, or substituents other than hydrogen located at the core atom of the porphyrin Derivatives having saturation of one or more chemical bonds of porphyrins (hydroporphyrins such as crawlin, bacteriochlorin, isobacteriochlorin, decahydroprofilin, corphin, pyrocorphine, etc.), porphyrin chains (extended Pylori inserted in porphyrin) Derivatives having one or more atoms comprising thio and pyromethenyl units, derivatives having one or more groups removed from porphyrin chains (contracted porphyrins such as corrin, corrole), and Combinations of derivatives (eg, phthalocyanine, basic-phthalocyanine, and porphyrin isomers) are included. Further suitable porphyrin derivatives include, but are not limited to, thiophyllin, pyroporphyrin, rhodoporphyrin, philoporphyrin, phyloerythrin, chlorophyllyl group including chlorophyll a and b, and deuteroporphyrin, deuterohemin Hemoglobin, including hemin, hematin, protoporphyrin, mesohemin, hematoporphyrin, mesoporphyrin, coproporphyrin, uroporphyrin, and turacin, and tetraallylazadipyrromethine.

  As will be appreciated by those skilled in the art, each unsaturation site, whether carbon or heteroatom, may contain one or more substituent groups as defined herein depending on the desired valence of the system. it can.

  Furthermore, the definition of “porphyrin” includes porphyrin complexes, which comprise a porphyrin proligand and at least one metal ion. Suitable metals for the porphyrin compounds depend on the heteroatoms used as coordination atoms, but are generally selected from transition metal ions. As used herein, the term “transition metal” refers to 38 elements from groups 3 to 12 of the periodic table. In typical transition metals, the valence electrons used to combine with these transition metal type elements are present in one or more electron shells, and thus often exhibit a number of common oxidation states. In certain embodiments, the transition metals of the invention include, but are not limited to, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, techetium. , Ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, palladium, gold, mercury, rutherfordium, and / or oxides and / or nitrides, and / or Includes alloys and / or mixtures of these materials.

  There are also many macrocycles based on cyclene derivatives, including macrocyclic proligands that are generally based on cyclen / cyclam derivatives, these macrocyclic proligands being skeletons by incorporating independently selected carbon or heteroatoms. Extensions can be included. In some embodiments, at least one R group is a surface active subunit, preferably electronically conjugated to the metal. In some embodiments, if at least one R group is a surface active subunit, two or more adjacent R2 groups form a cyclo or aryl group. In the present invention, the at least one R group is a surface active subunit or surface active moiety.

  Further, in some embodiments, macrocyclic complex dependent organometallic ligands are used. In addition to pure organic compounds for use as surface active moieties and various transition metal coordination complexes with 8-bonded organic ligands having donor atoms as heterocyclic or exocyclic substituents, There are a wide range of transition metal organometallic compounds available with bound organic ligands (Non-Patent Document 3, Chapter 26, Non-Patent Document 4, and Non-Patent Document 5, which are expressly incorporated herein by reference. See). Such organometallic ligands include cyclic aromatic compounds such as cyclopentadienide ion [C5H5 (-1)], and indenilides that produce a class of bis (cyclopentadiyl) metal compounds (ie, metallocenes) ( -1) Various ring-substituted derivatives and condensed ring derivatives such as ions are raised. See, for example, Non-Patent Document 6 and Non-Patent Document 7, which are incorporated by reference. Of these, ferrocene [(C5H5) 2Fe] and its derivatives are extensive chemical reactions (incorporated by reference, non-patent document 8) and electrochemical reactions (incorporated by reference, non-patent document 9; and non-patent documents). This is a prototype example that has been used in 10). Other potentially suitable organometallic ligands yield bis (arene) metal compounds and their ring-substituted and fused derivatives (of which bis (benzene) chromium is a prototypical example) And cyclic arenes such as benzene. Other acyclic n-linked ligands, such as allyl (-1) ions, or butadiene yields potentially suitable organometallic compounds, and any such ligands can contain other 7c-linked and 8 -In cooperation with the binding ligand, constitutes a general class of organometallic compounds in which metal-carbon bonds are present. All electrochemical studies of various dimers and oligomers of such compounds, with and without bridged organic and non-bridged ligands, and those with and without metal-metal bonds Useful.

  In some embodiments, the surface active moiety is a sandwich coordination complex. The term “sandwich coordination compound” or “sandwich coordination complex” refers to a compound of formula L-Mn-L, where each L is a heterocyclic ligand (as described below) and each M is a metal. , N is 2 or more, most preferably 2 or 3, and each metal is located between a pair of ligands and one or more heteroatoms (typically A plurality of, for example 2, 3, 4, 5 heteroatoms) (determined by the oxidation state of the metal). Therefore, a sandwich coordination compound is not an organometallic compound such as ferrocene in which a metal is bonded to a carbon atom. Ligands in sandwich coordination compounds are generally aligned in the stacking direction (ie, generally coplanarly oriented and axially aligned with each other, but they either rotate about the axis or do not rotate with respect to each other. (For example, see Non-Patent Document 11 incorporated by reference). Examples of sandwich coordination complexes include, but are not limited to, “double-decker sandwich coordination compounds” and “triple-decker sandwich coordination compounds”. The synthesis and use of sandwich coordination compounds is described in detail in US Pat. Nos. 5,099,049 and 4,049,45; the polymerization of these molecules is described in US Pat. Also included herein are individual substituents that find use in both “single macrocyclic” complexes.

  In addition, polymers of these sandwich compounds are also useful; such as “dyad” and “triad” as described in US Pat. Polymerization of these molecules as described in document 46 is included, all of which are incorporated herein by reference.

  Surface-active moieties containing non-macrocyclic chelators bind to metal ions to form non-macrocyclic chelates, because this is due to the presence of the metal and multiple proligands binding to each other resulting in multiple oxidation states. It is because it becomes possible to make it.

In some embodiments, a nitrogen donating proligand is used. Suitable nitrogen donating proligands are well known in the art and include, but are not limited to, NH ₂ ; NFIR; NRR ′; pyridine; pyrazine; isonikontinamide; imidazole; bipyridine and substituted derivatives of bipyridine; (Terpyridine) and substituted derivatives; phenanthroline, especially 1,10-phenanthroline (abbreviated phen) and substituted derivatives of phenanthroline such as 4,7-dimethylphenanthroline and dipyridol [3,2-a: 2 ′, 3′-c Phenazine (abbreviated as dppz), etc .; dipyridophenazine; 1,4,5,8,9,12-hexaazatriphenylene (abbreviated as hat); 9,10-phenanthrenequinone diimine (abbreviated as phi) ); 1,4,5,8-tetraazaphenanthre (Abbreviated tap); 1,4,8,11 (abbreviated as cyclam) tetraazacyclotetradecane and include isocyanide. Substituted derivatives including condensed derivatives may also be used. It should be noted that macrocyclic ligands that do not coordinately saturate the metal ion and require the addition of another proligand are considered non-macrocyclic for this purpose. As will be appreciated by those skilled in the art, it is possible to covalently attach several “non-macrocyclic” ligands to obtain a coordinately saturated compound, which has a cyclic skeleton. Absent.

  Suitable sigma donating ligands using carbon, oxygen, sulfur, and phosphorus are known in the art. For example, suitable sigma carbon donors can be found in Non-Patent Document 12, which is incorporated herein by reference (see, eg, page 38). Similarly, suitable oxygen ligands include crown ethers, water, and others known in the art. Also suitable are phosphines and substituted phosphines. See page 38 of Non-Patent Document 12.

  Oxygen, sulfur, phosphorus, and nitrogen donating ligands are attached to allow heteroatoms to function as coordinating atoms.

  In addition, some embodiments use multidentate ligands that are polynucleating ligands, for example, they can bind to more than one metal ion. These may be macrocyclic or non-macrocyclic. In the present specification, the molecular element may also comprise a polymer of surface active moieties as outlined above. For example, porphyrin polymers (including porphyrin complex polymers), macrocyclic complex polymers, surface active moieties including two surface active subunits, and the like can be used. The polymer may be a homopolymer or a heteropolymer and may include any number of various mixtures (admixtures) of monomer surface active moieties, where “monomer” includes two or more subunits. It may also contain surface active moieties (eg sandwich coordination compounds, porphyrin derivatives substituted with one or more ferrocenes, etc.). A surface active partial polymer is described in US Pat.

  In certain embodiments, the attachment group Y comprises an aryl functional group and / or an alkyl attachment group. In certain embodiments, the aryl functionality is amino, alkylamino, bromo, iodo, hydroxy, hydroxymethyl, formyl, bromomethyl, vinyl, allyl, S-acetylthiomethyl, Se-acetylselenomethyl, ethylnyl, 2- ( A functional group selected from the group consisting of (trimethylsilyl) ethynyl, mercapto, mercaptomethyl, 4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl, and dihydroxyphosphoryl. In certain embodiments, the alkyl attachment group is bromo, iodo, hydroxy, formyl, vinyl, mercapto, selenyl, S-acetylthio, Se-acetylseleno, ethynyl, 2- (trimethylsilyl) ethynyl, 4, 4, 5, 5 -Containing a functional group selected from the group consisting of tetramethyl-1,3,2-dioxaborolan-2-yl and dihydroxyphosphoryl. In certain embodiments, the attachment group comprises an alcohol or phosphonate.

In some embodiments, the surface active moiety is a silane characterized by the formula A _(4-x) SiB _x Y, wherein each A is independently a hydrolyzable group, such as a hydroxyl or alkoxy group, In the formula, x = 1 to 3, B is independently an alkyl or aryl group, and may or may not contain the attachment group Y as described above.

  In some embodiments, the present invention provides a method of manufacturing a PCB using a smooth copper substrate, ie, a copper substrate that has not been previously roughened. For example, suitable copper substrates for use in the method of the present invention include, but are not limited to, electrolytic copper or electroplated copper, electroless copper, and rolled copper, and are limited by the method of producing them. It is not done.

  In a further feature, the printed wiring board is provided with a polymeric material such as an epoxy, which includes a substantial amount of filler material such as, but not limited to, glass, silica, or other material. The surface is modified by a chemical adhesive material such as porphyrin that substantially alters the chemical compatibility of the surface to the metal, thereby facilitating strong adhesion between the polymer composite and the metal layer To. A second layer of chemical adhesion layer can be applied to the metal surface to promote adhesion between the metal surface and the subsequent polymer (epoxy / glass) layer. In some embodiments, the PCB is a multilayer conductor structure.

  In another aspect, the present invention stabilizes the copper surface by pre-cleaning the copper surface with an alkaline solution and / or a peroxide solution and forming the copper oxide on the pre-cleaned copper surface. Stopping the formation of copper oxide by a self-controlled reaction between the copper oxide and the one or more inhibitor compounds; joining the treated copper surface to the resin; A method of manufacturing a printed wiring board is provided. In some embodiments, one or more molecules can be bound to the copper oxide layer, and the one or more organic molecules are one or more bonds configured to bind to the copper oxide surface. A heat-stable base that carries a group and one or more attachment groups configured to adhere to a resin is provided.

[Experiment]
A number of experiments were conducted as described below. These examples are given for illustrative purposes only and are not intended to limit the invention in any way.

<Example 1: Treatment of smooth copper substrate>
This example illustrates one exemplary method of processing a smooth copper substrate in accordance with some embodiments of the present invention. As mentioned above, the method of the present invention allows the use of treated smooth copper substrates, ie copper substrates that have not been previously roughened. Such copper substrates can be formed from a variety of sources. For example, suitable copper substrates for use in the method of the present invention include, but are not limited to, electrolytic or electroplated copper, electroless copper, and rolled copper, and are limited to methods of preparing them. There is nothing. In this Example 1, the electrolytic copper substrate was first washed with 20-40 g / L sodium hydroxide solution at 40-60 ° C. for 2-5 minutes and then rinsed with water. The copper substrate is further washed with 1 to 3% by weight hydrogen peroxide solution + 2 to 5% by weight sulfuric acid at room temperature for 1 to 5 minutes, with 5 to 20% by weight sulfuric acid solution for 1 minute at room temperature and then with water. Was rinsed by. The substrate is then stabilized by oxidation in 140-200 g / L chlorite with 10-50 g / L sodium hydroxide containing less than 1% SAM at 50-80 ° C. for 2-8 minutes. And then rinsed with water. The sample can then be treated in a reducing bath of 10-40 g / L dimethylamine borane (DMAB) having a pH adjusted to 10.5-12.5 at room temperature to 40 ° C. for 2-5 minutes. . The sample is then rinsed and dried with hot air. The surface morphology and thickness of the stabilization layer can be adjusted by changing the concentration, temperature, and processing time of the processing solution and can be revealed by SEM, XRD, and Auger depth profiles.

  FIG. 3A shows a conventional electrolytic copper surface (ie, a smooth copper surface or, in other words, an unroughened copper surface) with unidirectional grain growth reflecting a nodular grain and a long-range ordered crystal structure. 2 is an exemplary SEM photo at 50,000 times showing typical morphology. As a comparison, the morphology of the electrolytic copper surface treated according to the method of the present invention is shown in FIG. 3B. As is very clear, the stabilization layer on the treated copper surface shown in FIG. 3B shows a finer grain, non-unidirectional grain growth and a more uniform morphology. Yes. In contrast, FIG. 3C shows an existing black oxide surface, which is very thick and shows a fragile fibrous structure. FIG. 3D is an exemplary SEM photo of an existing micro-etched copper surface, which shows a very non-uniform micro-cocoon morphology.

  The tabular data in FIG. 4 compares the surface roughness indicated by both Ra and Rz, demonstrating that the process of the present invention has not roughened the copper surface.

  The treated smooth copper surface stabilization layer, prepared according to Example 1, was further revealed by an Auger Electrophotometer (AES) to measure surface composition and layer thickness distribution. Referring to FIG. 5, the AES depth profile for the treated smooth copper surface shows that the stabilization layer comprises a mixture of copper and copper oxide, possibly cuprous oxide, and its thickness is about 100 nm. Show. In contrast, existing black oxide layers extend over a distance of about 1000 nm or more. The thickness of the stabilization layer is preferably in the range of 100 to 200 nm in order to ensure good bonding strength.

<Example 2: Proof of reinforcement of resin bonding on smooth copper surface>
This example shows one exemplary method for enhancing the bond strength of an epoxy to a smooth copper surface. The treated Cu test strip described above was placed on the temporary backing shown in FIG. A stabilized mass-produced 35 μm thick build-up (BU) epoxy (or dielectric) laminate film placed on top of the copper strip shown in FIGS. 7A-7D for at least 3 hours at ambient conditions. It was done. The assembly was then vacuum laminated at 100 ° C. for 30 seconds and pressed at 3 Kg / cm ² for 30 seconds. This lamination step was repeated twice to form a total of 3 ply BU films.

  It is worth noting that the copper surface changes from a reddish color to a light brown or green color after the surface treatment and then to a black color after laminating, suggesting that a scientific binding reaction has occurred. Resin surfaces often contain hydroxyl, amine, epoxy, and other chemically reactive groups that can react with oxygen rich copper surfaces by forming chemical bonds.

  In order to quantify the adhesive strength, a rigid backing substrate (stiffener) was laminated to the top surface of the BU film as shown in FIG. 7B. The assembly was then heat treated or cured at 180 ° C. for 90 minutes in a residence oven.

  The assembly was then cut into strips to remove the temporary backing substrate and separated into individual test coupons for testing using peel strength testing and highly accelerated stress testing (HAST). The resulting adhesive strength of the laminate was quantified using a force gauge of a peel tester at a peel angle of 90 ° C. and a peel speed of 50 mm / min for a 10 mm wide peel strip. In particular, the peel strength was tested on the substrate as originally formed and then tested after pretreatment and reflow. The pretreatment was performed at 125 ° C. for 25 hours, then at 192 ° C. and 60% relative humidity (RH). Reflow was performed three times at 260 ° C. A HAST test was then conducted for 96 hours at 130 ° C. and 85% relative humidity. 8A and 8B show the effect of treatment on the peel strength retention after the HAST test. The smooth test control (without the stabilizing layer according to the present invention) reduced the peel strength after HAST by 88%, and the conventional roughened test control showed a 40% decrease. In sharp contrast, a treated smooth copper substrate (ie, having a stabilization layer formed in accordance with the present invention) has not only a high initial peel strength, but also a high maintenance factor of only a 11% reduction. Indicated. Also, the tabular data in FIG. 8B shows that increased peel strength stability was achieved without change in surface roughness. This result was excellent and could not be predicted by the suggestion of the prior art.

  SEM cross-sections of laminated and treated smooth copper surfaces with stabilization layers were taken compared to standard roughened surfaces, and the method of the present invention hardly roughens the copper surfaces It has been shown.

  9A and 9B are SEM before and after HAST of a laminated and treated smooth copper surface with a stabilization layer formed in accordance with an embodiment of the present invention showing no delamination after reflow and HAST reliability tests. A cross-sectional photograph is shown.

  FIGS. 10A and 10B are typical SEM photographs of the peeled copper surface, where the copper-resin interface is just broken on the copper surface in the smooth copper test control (FIG. 10A), stable. It is shown that the treated smooth copper with the chemical layer is broken in the resin (FIG. 10B). This surprising result shows that the bond strength between the resin and the treated copper surface of the present invention is stronger than the bond strength of the bulk resin material itself.

<Example 3: Fine wiring patterning and electrical insulation reliability>
A device was formed to show that fine line patterning is possible with embodiments of the present invention. In particular, the comb-like pattern of wiring and space (50/50, 30/30, 20/20, 10/10, and 8/8 μm) having the same dimensions is described in Example 1 and Example 2. Processed and laminated according to the same procedure. The SEM cross-sectional view again confirmed that the method of the present invention did not roughen the copper wiring and that there was no delamination after reflow and HAST tests. The electrical insulation resistance is maintained above 10 ¹² Ω at 2 V after reflow and HAST, which is 5 orders of magnitude higher than the PCB manufacturing specification. Table 1 below summarizes the results. Good results have been obtained for all of these structures, showing that the process of the present invention, which is a major development to the prior art, greatly improves the ability to pattern copper interconnects in fine spaces.

<Example 4: Compatibility of laser drilling and via cleaning / plating on Cu surface laminated with epoxy>
Devices with laser vias were formed and further processed to show process compatibility. In particular, a smooth copper substrate was processed and laminated according to the same procedure as described in Example 1 and Example 2. Via arrays with diameters of 30, 40, 50, 75, 100, 150, and 200 μm were prepared by drilling with CO ₂ and UV lasers. The via structure was then subjected to a soft etch and pickling, or desmear process, followed by electroless copper plating and then electrolytic plating. FIG. 11 shows a SEM cross-section of a laser via formed on a laminated smooth processed copper surface formed in accordance with an embodiment of the present invention, showing no undercut and delamination after the desmear and plating process. Yes.

Example 5 Demonstration of Strengthening Solder Resist Bonding on Smooth Copper Surface
This example shows one exemplary method for enhancing the adhesion of solder resist on a smooth copper substrate. A smooth copper test strip was processed according to the same procedure as described in Example 1 and placed on a temporary backing as shown in FIG. A 30 μm thick commercially available solder resist (SR) laminate film stabilized for 3 hours at ambient conditions was placed on top of the copper strip as shown by FIG. 7A. The assembly was then vacuum laminated at 75 ° C. for 30 seconds and pressed at 1 Kg / cm ² for 60 seconds. This assembly was then subjected to 400 mJ / cm ² UV exposure and then cured at 150 ° C. for 60 minutes in a residence oven and post UV cured at 1000 mJ / cm ² .

  In order to quantify the adhesive strength, a rigid backing substrate (stiffener) was laminated onto the top surface of the SR film as shown by FIG. 7B. This assembly was then diced to remove the temporary backing substrate and then separated into individual specimens for peel strength testing and high accelerated stress testing (HAST). In particular, peel strength was tested against the original substrate formed and then tested after pretreatment, reflow, and HAST. 12A and 12B illustrate the effect of the treatment method of the present invention on the peel strength retention after the HAST test. The untreated smooth test control showed a 87% reduction in peel strength after HAST, and the conventional roughened test control showed a 69% reduction. In sharp contrast, the treated smooth copper surface formed in accordance with embodiments of the present invention exhibited a high peel strength retention of only a 22% drop as well as a higher initial peel strength. . Also, the tabular data in FIG. 12B shows that increased peel strength stability was achieved without change in surface roughness.

<Example 6: Proof of compatibility between UV patterning and via cleaning / plating on Cu surface laminated with SR>
Devices consisting of via arrays and copper interconnects were formed and then further processed to prove process compatibility. In particular, a smooth copper substrate was processed and laminated according to the same procedure as described in Example 5. A via array consisting of a bottom diameter ranging from 80 to 440 μm and a copper wiring having a width of 62 to 500 μm was formed through UV exposure and development. FIG. 13A shows a copper wiring pattern and a via row, and FIG. 13B shows a ball grid array (BGA) pattern. The patterned structure was then subjected to a soft etch and pickling, or desmear process, followed by electroless Ni plating, followed by Au emulsion deposition. FIG. 14 is an SEM cross-sectional image of an SR via formed on laminated smooth copper demonstrating no delamination after the desmear and plating process. In all these structures, good results have been obtained suggesting that the processing method of the present invention greatly improves the ability to pattern microspaced SR, which is a major advance in the art.

  The methods, apparatus, and descriptions above are intended to be illustrative. In view of the teachings provided herein, other methods will be apparent to those skilled in the art and such methods are intended to fall within the scope of the present invention.

Claims (11)

At least one copper layer;
At least one polymer material layer;
A stabilizing layer between the copper layer and the polymeric material layer;
With
The stabilization layer includes a plurality of grains having a size of about 250 nm or less, the grains are substantially randomly oriented, and the surface of the copper layer exhibits a roughness of about 0.14 μmRa or less. ,
The surface of the copper layer is
Stabilizing the copper surface by forming a copper oxide layer on the copper surface and coupling one or more molecules to the copper oxide layer, wherein the copper surface comprises the copper By exposing the surface to an oxidation bath of 140-200 g / L oxidant with 10-40 g / L sodium hydroxide and less than 1% surface active moiety (SAM) at a temperature of 50-80 ° C. Stabilized, the one or more molecules are the surface active moiety, and the surface active moiety is a silane characterized by the formula A _(4-x) SiB _x Y, wherein A is independently A hydrolyzable group, x = 1-3, B is independently an alkyl or aryl group, and Y is an aryl functional group or an alkyl attachment group, or both;
Adjusting the stabilized copper surface by reducing the copper oxide layer with a reducing agent, wherein the stabilized copper surface has a pH adjusted to 10.5 to 12.5. In a reducing bath of 10 to 40 g / L of the reducing agent, adjusted at room temperature to 50 ° C., the reducing agent is formaldehyde, sodium thiosulfate, sodium borohydride, general formula BH ₃ NHRR ′ (R and R ′ Are each selected from the group consisting of H, CH ₃ , CH ₂ CH ₃ ), and borane reducing agents including dimethylamine borane (DMAB), morpholine borane, pyridine borane, and cyclic borane including piperidine borane A printed wiring board formed by a process including a step selected from any one or more of:   The printed wiring board according to claim 1, wherein the grains have a size of 200 nm or less.   The printed wiring board according to claim 1, wherein the grains have a size of 100 nm or less.   The printed wiring board according to claim 1, wherein the stabilization layer has a thickness of 500 nm or less.   The printed wiring board according to claim 1, wherein the stabilization layer has a thickness of 300 nm or less.   The printed wiring board according to claim 1, wherein the stabilization layer has a thickness of about 100 nm to 200 nm.   The printed wiring board according to claim 1, wherein the grains exhibit unidirectional grain growth and substantial uniformity.   The printed wiring board according to claim 1, wherein the stabilization layer includes cuprous oxide.   The printed wiring board according to claim 1, wherein the copper layer includes electrolytic copper, electroplated copper, electrodeposited copper, electroless plated copper, rolled copper, or a combination thereof.   The printed wiring board according to claim 1, wherein the polymer material layer includes a dielectric resin.   The printed wiring board according to claim 1, wherein the polymer material layer includes an epoxy or an epoxy including a filler material, and the filler material includes glass, silica, and a mixture thereof.