Chemical binding of surface polymer to epoxy material

Abstract

The present disclosure relates to the chemical binding of surface polymers to epoxy materials. More specifically, the present disclosure relates to the adhesion of an epoxy material to a substrate by bonding of functional groups present in a surface polymer formed on a substrate to functional groups present in the epoxy material.

Description

[0001] Chemical Binding of Surface Polymer to Epoxy Material

[0002] Cross-Reference to Related Applications

[0003] This application claims the benefit of U. S. Provisional Patent Application No. 63 / 716,851, titled “Chemical Binding of Surface Polymer to Epoxy Material”, filed November 6, 2024, the entire contents of which is incorporated by reference herein.

[0004] Field

[0005] The present disclosure relates to the chemical binding of surface polymers to epoxy materials. More specifically, the present disclosure relates to the adhesion of an epoxy material to a substrate by bonding of functional groups present in a surface polymer formed on a substrate to functional groups present in the epoxy material.

[0006] Background

[0007] Forming polymeric structures on surfaces have become increasingly important in many technologies and applications. “Surface polymers”, “surface bound polymers” or “polymers on a surface” all describe a polymeric structure having polymer chains that are chemically bonded to a surface at one end through covalently bound polymerization initiators. Two methods, known by persons skilled in the art, can be used to achieve such polymeric structure, namely the “grafting to”-approach and the “grafting from” -approach (See Fig. 1 and Fig. 2). In the “grafting to”-approach (Fig. 1), polymers are pre-prepared in solution and then deposited onto the surface in question, since the pre-prepared polymers are designed in such a way that one of the chain-ends has some affinity for the surface of interest. Upon contact with the surface of interest, the polymers will self-assemble on said surface forming surface bound polymers. In the “grafting from” -approach (Fig. 2), small molecules capable of acting as polymerization initiators are covalently bound to the surface of interest in a prepolymerization step. Subsequently polymerization is initiated via the polymerization initiators bonded on the surface. Accordingly, surface polymers are formed from the surface monomer-by-monomer.

[0008] While the “grafting to” approach allows for simple preparation procedures and detailed characterization, in that one can prepare the polymers using conventional polymerization methods that can maintain the bonding-to- surface property at the one end of the pre-formed polymer, before initiating the self-assembly procedure, the “grafting to”-approach lacks the ability to form high density surface bound polymeric structures nor flexibility in polymer structures, composition, etc. Main equilibrium conformation of long polymeric structures in solution is a contracted, or a coiled polymer chain, unless the polymer solution is extremely diluted with highly solvating solvent or other means employed to stabilize extended conformation (e g., pH for ionic polymers). Such extra means to stabilize extended polymer chain conformation may complicate and interfere with the “grafting to” process conditions and make the approach less practical. Therefore, the self-assembly process is being halted by the steric repulsion between the coils of pre-made polymer chains as they self-assemble on the surface leading to loosely packed polymer coils on the surface (see Fig, 1). The “grafting from”-approach allows for the formation of highly dense surface bound polymer structures, as the small initiating molecules can form a much more densely packed layer on the surface (compared to large polymer molecules, see Fig. 2). Such a densely packed layer of initiating molecules is guiding monomer molecule-by-monomer molecule formation of polymer chains, where the extended conformation of growing polymer chains is sterically stabilized by their close proximity to each other. As such, the surface bound polymer structure formed by a “grafting from” approach results in a much higher density of polymer chains. Additionally, as the “grafting from” -approach allows for highly dense surface bound polymer structures, a brush-like structure can be achieved, thus, the name “polymer brush”. In these structures, the polymers are stretched and forced to stand upright due to the steric repulsion between neighboring polymers creating a unique structure known by people skilled in the art as a “polymer brush” structure. On surfaces, these structures are tethered / attached, usually covalently, at one end to the surface, typically to a solid or semisolid surface, thereby differing from polymers formed in solution and subsequently deposited onto a surface.

[0009] As mentioned above, surface polymers are prepared by one of the following two main strategies: “grafting to” or “grafting from”. In the “grafting to”-approach, polymer chains are deposited onto the surface in question. The “grafting to”-approach suffers from several drawbacks and limitations making it difficult to produce thick and dense surface polymers. In the “grafting from” -approach, the surface polymer growth (surface polymer chain propagation, extension of the chain by monomer units) is initiated from initiator-functionalized surfaces, using, for example, a controlled / ”living” polymerization technique, such as anionic polymerization, cationic polymerization, ring-opening polymerization, and controlled radical polymerization. Surface polymers within the present context are, thus, polymeric structures having polymer chains that are chemically bonded to a surface at one end. Such polymers can be tailored to provide specific chemical and / or physical properties and can produce precisely tailored chemical structures on a molecular scale. They may be used, for example, for storing certain chemical species, controlling transport properties, improving surface stability and properties, creating an interface in which dissimilar materials can bind or interact, and other functions. Surface polymers can subsequently join otherwise incompatible materials such as metals and plastics and improve adhesion between such otherwise incompatible materials (see, e.g., WO 2014 / 075695 Al).

[0010] Different polymerization techniques have facilitated the specific design and synthesis of surface polymers with strict molecular control and desired properties. In particular, the surface polymers can be viewed as nanoscale “building blocks” with a wide range of uses, varying from redox activity to biocompatibility and surface alteration, and due to the flexibility of the surface polymers, highly-tailored thin films of surface polymers can be created with respect to chemical composition, thickness, density and architecture.

[0011] Thus, specific applications may require specific design of surface polymers. Such design of surface polymers may result in improved surface properties.

[0012] Summary- Disclosed herein is a device stack comprising: a substrate with a first surface, a surface polymer on at least a portion of the first surface, and a layer of epoxy material over the first surface of the substrate, wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide. The substrate may be a glass material or a copper material. The epoxy material may comprise an epoxide component and an alcohol component, an ester component, or a cyanate ester component. The epoxy material may be of Ajinomoto Build-up Film (ABF) GX series, GL series, GZ series, or GY series. The surface polymer may comprise poly(hydroxyethyl methacrylate) (PHEMA), poly(acrylamide) (PAM), poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), poly(4-vinylaniline) (P4VA), poly(2-aminoethyl methacrylate) (PAEM), post-modified poly(glycidyl methacrylate) (PGMA), or post-modified polystyrene (PSt). In some instances, the surface polymer may comprise poly(glycidyl methacrylate) (PGMA) and / or poly(hydroxyethyl methacrylate) (PHEMA). The device stack may be formed by heating, heat pressing, lamination, or vacuum lamination. The device stack may subjected to a curing process.

[0013] In an aspect of the present disclosure, a device stack is provided, the device stack comprising: a substrate with a first surface, a surface polymer on at least a portion of the first surface, and a layer of epoxy material over the first surface of the substrate, wherein the surface polymer is formed by: providing a substrate, exposing the substrate to a polymerization initiator, exposing the substrate to a reaction composition comprising: a monomer, a catalyst, a ligand, an activator, and optionally a solvent, and optionally post-modifying the surface polymer on the substrate, and wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or wherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide. The substrate may be a glass material or a copper material. The epoxy material may comprise an epoxide component and an alcohol component, an ester component, or a cyanate ester component. In some instances, the epoxy material may be of Ajinomoto Build-up Film (ABF) GX series, GL series, GZ series or GY series. The monomer may be selected from hydroxyethyl methacrylate (HEMA), acrylamide (AM), acrylic acid (AA), methacrylic acid (MAA), 4-vinylaniline (4VA), 2-aminoethyl methacrylate (AEM), glycidyl methacrylate (GMA), and styrene (St). The catalyst may be derived from copper (Cu), iron (Fe) or ruthenium (Ru). The ligand may be selected from AT, AyV’,jV”, Ar”-pentamethyldiethylene-triamine (PMDETA), tris[2-(dimethylamino)ethyl]amine (Me6TREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TPMA), 1, 1,4,7, 10, 10-hexamethyltriethylenetetramine (HMTETA); tetramethylethylenediamine (TMEDA), 1,4, 8,1 l-tetramethyl-1,4,8,11 -tetraazacyclotetradecane (Me4Cyclam), and / or 2,2 ’-bipyridyl (BiPy). The catalyst activator may be selected from sodium ascorbate, ascorbic acid, hydrazine, hydrazine hydrate, sodium hypophosphite, glucose, tin 2- ethylhexanoate, sodium phenoxide, sodium dithionite, a mixture of iron powder and sodium chloride, hydrogen carbonate, citric acid, and pyrogallic acid, as well as mixtures thereof. The solvent may be selected from methanol, ethanol, isopropanol, water, and mixtures thereof

[0014] In an aspect of the present disclosure, a method of preparing a surface polymer for a device stack as described herein is provided, the method comprising: providing the substrate, wherein polymerization initiators are covalently bound to a surface of the substrate, exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand, an activator, and optionally a solvent to form surface polymers on the substrate, wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or wherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide. In the method, the surface polymer may be post-modified. The monomer may be selected from hydroxyethyl methacrylate (HEMA), acrylamide (AM), acrylic acid ( AA), methacrylic acid (MAA), 4-vinylaniline (4VA), 2-aminoethyl methacrylate (AEM), glycidyl methacrylate (GMA), and styrene (St). In the method, the catalyst may be derived from copper (Cu), iron (Fe) or ruthenium (Ru). In the method, the ligand may be selected from A(A(r(A’’, ”’-pentametliyldiethylene-triamine (PMDETA), tris[2-(dimethylamino)ethyl]amine (Me6TREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TPMA), 1,1,4,7,10,10-hexa-methyltriethylenetetramine (HMTETA); tetramethylethylenediamine (TMEDA), 1, 4, 8, 11 -tetramethyl- 1,4, 8,11 -tetraazacyclotetradecane (Me4Cyclam), and / or 2,2’-bipyridyl (BiPy). In the method, the catalyst activator may be selected from sodium ascorbate, ascorbic acid, hydrazine, hydrazine hydrate, sodium hypophosphite, glucose, tin 2-ethylhexanoate, sodium phenoxide, sodium dithionite, a mixture of iron powder and sodium chloride, hydrogen carbonate, citric acid, and pyrogallic acid, as well as mixtures thereof. In the method, the solvent may be selected from methanol, ethanol, isopropanol, water, and mixtures thereof.

[0015] In an aspect of the present disclosure, a method of preparing device stack as described herein is provided, the method comprising: providing the substrate, wherein surface polymers are present on at least a portion of the surface of the substrate, and wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and the functional groups are selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or wherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, providing the epoxy material, and bonding the substrate and the epoxy material by heating, heat pressing, lamination, or vacuum lamination. On the method, the substrate may be a glass material or a copper material. In the method the epoxy material may comprise an epoxide component and an alcohol component, an ester component, or a cyanate ester component. In the method, the epoxy material may be an Ajinomoto Build-up Film (ABF) GX senes, GL series, GZ series, or GY series. In the method, the surface polymer may comprise poly (hydroxy ethyl methacrylate) (PHEMA), poly(acrylamide) (PAM), poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), poly(4-vinylaniline) (P4VA), poly(2-aminoethyl methacrylate) (PAEM), post-modified poly(glycidyl methacrylate) (PGMA), or post-modified polystyrene (PSt). In some instances, the surface polymer may comprise poly(glycidyl methacrylate) (PGMA), and / or poly(hydroxyethyl methacrylate) (PHEMA). The device stack may be formed by heating, heat pressing, lamination, or vacuum lamination. The device stack may be subjected to a curing process.

[0016] In an aspect of the present disclosure, a method of preparing device stack as described herein is provided, the method comprising: providing the substrate, wherein initiators are covalently bound to a surface of the substrate, exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand, an activator, and optionally a solvent to form surface polymers on the substrate, wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or wherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, optionally post-modifying the surface polymer formed on the substrate, providing the epoxy material, and bonding the substrate and the epoxy material by heating, heat pressing, lamination, or vacuum lamination. In the method, the substrate may be a glass material or a copper material. In the method, the epoxy material may comprise an epoxide component and an alcohol component, an ester component, or a cyanate ester component. In some instances, the epoxy material may be an Ajinomoto Build-up Film (ABF) GX series, GL series, GZ series, or GY series. In the method, the monomer may be selected from hydroxyethyl methacrylate (HEMA), acrylamide (AM), acrylic acid (AA), methacrylic acid (MAA), 4-vinylaniline (4VA), 2-aminoethyl methacrylate (AEM), glycidyl methacrylate (GMA), and polystyrene (St). In the method, the catalyst may be derived from copper (Cu), iron (Fe) or ruthenium (Ru). In the method, the ligand may be selected from A^A^V^VtyV’ -pentamethyldiethylene-triamine (PMDETA), tris[2-(dimethylamino)ethyl]amine (Me6TREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TPMA), 1, 1,4,7, 10, 10-hexamethyltriethylenetetramine (HMTETA); tetramethylethylenediamine (TMEDA), 1,4, 8,11 -tetramethyl- 1,4,8,11 -tetraazacyclotetradecane (Me4Cyclam), and / or 2,2’ -bipyridyl (BiPy). In the method, the catalyst activator may be selected from sodium ascorbate, ascorbic acid, hydrazine, hydrazine hydrate, sodium hypophosphite, glucose, tin 2-ethylhexanoate, sodium phenoxide, sodium dithionite, a mixture of iron powder and sodium chloride, hydrogen carbonate, citric acid, and pyrogallic acid, as well as mixtures thereof. In the method, the solvent may be selected from methanol, ethanol, isopropanol, water, and mixtures thereof.

[0017] In an aspect of the present disclosure, a system for forming surface polymers on a substrate for a device stack as described herein is provided, the system comprising: a reaction composition container containing a reaction composition, said reaction composition comprising: a monomer, a catalyst, a ligand, a catalyst activator, and optionally a solvent, a substrate displacement device for bringing at least a portion of a polymerization initiator-modified substrate into contact with the reaction composition in the reaction composition container for a controlled time, wherein the controlled time is sufficient for surface polymers to be formed on the portion of the polymerization initiator-modified substrate, wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or wherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide. The system may comprise a reaction composition container containing a reaction composition, said reaction composition comprising: a monomer, a catalyst, a ligand, a catalyst activator, and optionally a solvent, a substrate displacement device for bringing at least a portion of a polymerization initiator-modified substrate into contact with the reaction composition in the reaction composition container for a controlled time, wherein the controlled time is sufficient for surface polymers to be formed on the portion of the polymerization initiator-modified substrate, wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or wherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, and optionally a post-modification container holding a post-modification reagent for post-modifying the formed surface polymer, wherein the substrate displacement device is further configured for bringing at least a portion of the surface polymer coated substrate into contact with the post-modification reagent composition in the post-modification container for a controlled time, and wherein the controlled time is sufficient for post-modifying the surface polymers, and optionally a device for bonding the substrate and the epoxy material by heating, heat pressing, lamination, or vacuum lamination to form the device stack. The substrate displacement device may comprise any one of: a conveyor system, a programmable mechanical arm, or a roll-to-roll mechanism. The system may further comprise a polymerization initiator container containing a polymerization initiator agent, wherein the substrate displacement device is further configured to bring the portion of the substrate for attachment of polymerization initiators into contact with the polymerization initiator agent to form polymerization initiators at the substrate surface, prior to bringing the portion of the polymerization initiator-modified substrate into contact with the reaction composition. The system may further comprise a cleaning container, the cleaning container containing a cleaning agent, wherein the substrate displacement device is configured to bring the portion of the polymerization initiator-modified substrate into contact with the cleaning agent prior to, or subsequent to, bringing the portion of the polymerization initiator-modified substrate into contact with the reaction composition, and optionally the substrate displacement device is configured to bring the portion of substrate into contact with the cleaning agent prior to, or subsequent to, bringing the portion of the substrate into contact with the polymerization initiator. In the system, the polymerization initiator container may be a vacuum oven.

[0018] Description of the drawings

[0019] Certain embodiments of the matter disclosed herein are illustrated in the accompanying drawings. The drawings are, however, in no way intended to limit the scope of the disclosure. In the drawings: Fig. 1 illustrates the “grafting to” principle schematically.

[0020] Fig. 2 illustrates the “grafting from” principle schematically.

[0021] Fig. 3 is a schematic illustration of a device stack (200) with surface polymer (202) grafted from a substrate (203), where the surface polymer is bonded to an epoxy material (201). Fig, 4 is a schematic illustration of a system for forming surface polymers on at least a portion of a substrate, according to embodiments of the present invention.

[0022] Fig, 5 is a schematic illustration of an exemplary substrate displacement device, the substrate displacement device comprising a roll-to-roll processing device, in accordance with an embodiment.

[0023] Fig. 6 shows the average dry film thickness as determined by profilometry, see Example 6. Fig, 7 shows Grazing Angle IR (GA-IR) spectra of polymerizations of Example 6.

[0024] Fig. 8 shows the dependence between the C=O peak intensity and the surface polymer thickness, see Example 6.

[0025] Fig. 9 shows Reference substrate 1 (1 (ref.)) with 4 sheets of ABF GX92 before thermal cycling, see Example 9.

[0026] Fig. 10 shows substrate 1 (ref) following 100 thermal cycles, see Example 9.

[0027] Fig. 11 shows substrate I (ref.) following 300 thermal cycles, see Example 9.

[0028] Fig. 12 shows substrate 1 (ref.) following 500 thermal cycles, see Example 9.

[0029] Fig. 13 shows substrate 2 (ref.) before thermal cycling, see Example 9.

[0030] Fig. 14 show substrate 2 (ref.) before thermal cycling, see Example 9.

[0031] Fig. 15 shows substrate 2 (ref.) following 100 thermal cycles, see Example 9.

[0032] Fig. 16 shows substrate 2 (ref.) following 250 thermal cycles, see Example 9.

[0033] Fig. 17 shows substrate 2 (ref.) following 450 thermal cycles, see Example 9.

[0034] Fig 18 shows substrate 2 (ref.) following 1000 thermal cycles, see Example 9.

[0035] Fig. 19 shows substrate 3 before thermal cycling, see Example 9.

[0036] Fig. 20 shows substrate 3 following 100 thermal cycles, see Example 9.

[0037] Fig. 21 shows substrate 3 following 250 thermal cycles, see Example 9.

[0038] Fig. 22 shows substrate 3 following 450 thermal cycles, see Example 9.

[0039] Fig. 23 shows substrate 3 following 1000 thermal cycles, see Example 9.

[0040] Fig. 24 shows substrate 4 before thermal cycling, see Example 9. Fig. 25 shows substrate 4 following 100 thermal cycles, see Example 9.

[0041] Fig. 26 shows substrate 4 following 250 thermal cycles, see Example 9.

[0042] Fig. 27 shows substrate 4 following 450 thermal cycles, see Example 9.

[0043] Fig. 28 shows substrate 4 following 1000 cycles, see Example 9.

[0044] Detailed description

[0045] Disclosed herein is a device stack comprising a substrate having surface polymers on at least a portion of a surface, and an epoxy material, wherein certain functional groups present in the polymeric structure of the surface polymer chains may bind chemically to certain functional groups present in the epoxy material. The chemical binding of the surface polymer to the epoxy material may be facilitated by certain heating and lamination procedures.

[0046] Thus, in an aspect of the present disclosure, a device stack is disclosed, the device stack comprising: a substrate with a first surface, a surface polymer on at least a portion of the first surface, and a layer of epoxy material over the first surface of the substrate, wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide.

[0047] Thus, if epoxide groups are present in the epoxy material, then hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide groups present m the surface polymer may react with and bind to said epoxide groups in the epoxy material.

[0048] Thus, if the surface polymer comprises epoxide groups, then hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide groups present in the epoxy material may react with and bind to said epoxide groups in the surface polymer.

[0049] The device stack may comprise a substrate with a first surface, a surface polymer on at least a portion of the first surface, and a layer of epoxy material over the first surface of the substrate, wherein the surface polymer may formed by providing a substrate, exposing the substrate to a polymerization initiator, exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand, an activator, and optionally a solvent, and optionally post-modifying the surface polymer on the substrate, and wherein the surface polymer may comprise functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or wherein the surface polymer may comprise epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide.

[0050] It is expected that a wide range of different substrates will be useful in connection with the disclosure herein. Substrates may wholly or partly be composed of metal (like aluminum, steel, nickel, gold, silver, platinum, chrome, copper, iron and alloys), glass, carbon, graphite, graphene, carbon black, monoclays, ceramics, composite materials, plastics, polymer materials, semiconductors, compound semiconductors (e.g., gallium arsenide (GaAs), gallium nitride (GaN), germanium sulfide (GeS), and indium phosphide (InP)), and particles (e.g., Si, metal, metal alloys and coated particles). Substrates may be patterned or unpatterned. If patterned, substrate surface(s) may comprise one or more of the mentioned substrate materials. The substrate may be composed of several layers of different materials, optionally being attached together, e.g., using a glue or by laminating, or be a blend of different materials. The substrate may have any size, shape and structure, including an elongated structure, and may be in the form of pieces, threads, fibers, cables, wires, hollow structures, particles, nanoparticles, monolayers etc. Particles and nanoparticles may be uncoated or coated with another material and may further be in the form of aggregates (multiple (nano)particles forming an assembly of individual (nano)particles). Aggregates may in some cases be viewed as one (nano)particle. Substrates may also be composed of one or more of the above mentioned, e.g., the substrate may be a base material comprising glass, silicon, GaAs, GaN, GeS, Ini’, dielectric material, ceramic, composite, as well as layered and patterned structures thereof. Substrates may have any form and shape, be elongated, be hollow, have protrusions or recesses, etc. In some instances, the substrate may be a glass material or a copper material. Epoxy materials are materials comprising epoxide groups (also known as oxirane groups). Epoxy material may comprise other components in addition to an epoxide component, such as an alcohol component, an ester component, or a cyanate ester component.

[0051] In some instances, the epoxy material may be an Ajinomoto Build-up Film (ABF). The ABF may, e.g., be ABF GX series, ABF GL senes, ABF GZ series, or ABF GY senes.

[0052] The monomer to be used within the present context may be such having an epoxide functional group and / or a functional group selected from hydroxyl (inclusive alcohols and phenols), carboxylic acid, amine, thiol, cyanate ester, and amide groups bonding to or reacting with a functional group in the epoxy material, the functional group being selected from epoxide, hydroxyl (inclusive alcohols and phenols), carboxylic acid, amine, thiol, cyanate ester, and amide, or a monomer which can be postmodified thereto. In the below table, compatible functional groups on the surface polymer and the epoxy material, respectively, are indicated.

[0053] Functional group in the surface polymer Compatible functional group in the epoxy material

[0054] Hydroxyl (incl. alcohols and phenols)

[0055] Carboxylic acids

[0056] Amines

[0057] Epoxides

[0058] Primary or secondary amides

[0059] Thiols

[0060] Cyanate esters

[0061] Esters

[0062] Hydroxyl (incl. alcohols and phenols) Carboxylic acids

[0063] Epoxides Amines

[0064] Primary or secondary amides

[0065] Thiols Cyanate esters

[0066] Esters

[0067] The monomer may in particular be selected from methacrylates, acrylamides, acrylic acids, vinylalinines, and styrenes. Examples of suited monomers include hydroxyethyl methacrylate (HEMA), acrylamide (AM), acrylic acid (AA), methacrylic acid (MAA), 4-vinylaniline (4VA), 2-aminoethyl methacrylate (AEM), glycidyl methacrylate (GMA), and styrene (St),

[0068] Following formation of the surface polymer, the formed surface polymer is indicated with a “P” as prefix to the monomer. By way of example, methyl methacrylate monomer is denoted MMA, and after polymerization (surface polymer propagation), the polymer molecule is denoted PMMA. Likewise, 2-hydroxyethyl methacrylate is denoted HEMA, and after polymerization, the polymer molecule is denoted PHEMA. Typically, each surface polymer chain on the surface of the substrate may be composed of monomeric units in the range of 100 to 10,000.

[0069] Accordingly, the surface polymer may comprise poly(hydroxyethyl methacrylate) (PHEMA), poly(acrylamide) (P / XM), poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), poly(4-vinylaniline) (P4VA), poly(2-aminoethyl methacrylate) (PAEM), poly(glycidyl methacrylate) (PGMA), poly(styrene) (PSt), post-modified poly(glycidyl methacrylate) (PGMA), or post-modified polystyrene (PSt). Functional groups present in these surface polymers may bind chemically to epoxide groups or to functional groups selected from hydroxyl (including alcohols and phenols), carboxylic acid, anime, thiol, cyanate ester, or amide present in the epoxy material.

[0070] Post-modification of formed surface polymers may include addition, substitution, elimination, deprotection, reduction, oxidation, cyclization, or rearrangement of functionalities present in the monomeric units of the surface polymer. Suited monomers for post-modification include methacrylates (including glycidyl methacrylate), acrylates, acrylamides, and styrenes.

[0071] To form the device stack, the substrate with the surface polymer and the epoxy material are layered, and device stack is formed by heating, heat pressing, lamination, or vacuum lamination for a sufficient period of time, such as 30 seconds or 1 h. The device stack may be formed at room temperature or elevated temperatures such as 100°C, 150°C, or 250°C. The device stack may be formed at reduced pressure (vacuum lamination), at ambient pressure, or with increased pressure (heat pressing) during the device stack formation. The device stack may be formed through multiple consecutive steps such as heat pressing at 0.8 MPa and 150°C for 30 seconds, followed by heating at 250°C for 30 minutes. The device stack may be subjected to curing procedures following the formation of the device stack. Curing procedures are, e.g., described in ACS Omega 8, 32907-32916, 2023,

[0072] A method of preparing a surface polymer for a device stack as defined herein is provided, the method comprising providing the substrate, wherein polymerization initiators are covalently bound to a surface of the substrate, exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand, an activator, and optionally a solvent to form surface polymers on the substrate, wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or wherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide.

[0073] The obtained surface polymer may be post-modified so as to form certain desired functional groups that may bond to certain functional groups in the epoxy material. Such post-modification procedures are described above.

[0074] The method of preparing device stack as defined herein may comprise providing the substrate, wherein surface polymers are present on at least a portion of the surface of the substrate, and wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and the functional groups are selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or wherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, providing the epoxy material, and bonding the substrate and the epoxy material by heating, heat pressing, lamination, or vacuum lamination. The method of preparing device stack as described herein may comprise providing the substrate, wherein initiators are covalently bound to a surface of the substrate, exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand, an activator, and optionally a solvent to form surface polymers on the substrate, wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or wherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, optionally post-modifying the surface polymer formed on the substrate, providing the epoxy material, and bonding the substrate and the epoxy material by heating, heat pressing, lamination, or vacuum lamination. Suited procedures for binding the surface polymer to the epoxy material are described above.

[0075] To propagate surface polymer chains from the surface of the substrate, polymerization initiators may firstly be attached to a portion of the surface of interest for surface polymer formation. The attachment process is further described below. The procedures may in general apply to all types of substrates. It is to be understood that modifying a substrate with initiators will generally result in a multiplicity of initiators being attached to the surface of the substrate. The initiators may be attached to available surface modification sites on the substrate. Prior to attachment of polymerization initiators, the surface of the substrate may be cleaned using various techniques, including sonication m ammonia, ABC-clean A200, a solution of DI-water: NH3: H2. O2 (5:1:1), acetone, and / or water. Following attachment of polymerization initiators, the substrate may be annealed at ambient conditions or at elevated temperatures.

[0076] If only specific areas of a material surface are to be exposed to polymerization initiators, the particular area(s) on the surface may be blocked, e.g., chemically or by using a foil, seal or cover, or etched, or masked, protected, or defined by lithographic patterning. Also, a non-polymenzation initiator (“dummy” initiator, i.e. a substance that cannot initiate surface polymer propagation) may be used together with the polymerization initiator to “dilute” the attachment of polymerization initiators.

[0077] 1-step silane grafting: Polymerization initiators may be attached to at least a surface or a portion of a surface in one step by silane grafting of trialkoxysilane with substituted benzyl / benzyl halide or substituted tertiary’ / tertiary halide groups. The silane grafting is normally performed by vapor deposition, in solution, by spray coating, or paint- on coating.

[0078] 1-step diazonium grafting:

[0079] Surface modification substances (polymerization initiators and / or “dummy” initiators) may be atached to at least a surface or a portion of a surface in one step by grafting aryl diazonium salts with substituted benzyl groups / benzyl halide groups. The diazonium grafting is normally performed either by activating the aryl diazonium salt electrochemically or chemically or by spontaneous reaction. Diazonium salts can be pre-synthesized before being used for grafting reaction or formed in-situ during grafting reaction from a set of precursors added to the grafting reaction solution,

[0080] 2-step diazonium grafting 2-step:

[0081] / Another route of polymerization initiator atachment is by a two-step process. The first step being grafting of an aryl diazonium salt that contains a nucleophilic group (alcohol or amine). In a second step, a nucleophilic acyl substitution reaction adds a halogen containing group, giving the attached polymerization initiator.

[0082] 2-step silane grafting:

[0083] The first step being grafting of a silane that contains a nucleophilic group (alcohol or amine). In a second step, a nucleophilic acyl substitution reaction adds a halogen containing group, giving the attached polymerization initiator.

[0084] Other processes for forming the polymerization initiator layer may be applied.

[0085] An example of a polymerization initiator is p-(chloromethyl)phenyltrimethoxysilane (CPTMS) which may be atached using a vapor deposition method or a dipping method. Another example is a-bromobutyryl bromide (BiBB). Another example is the polymerization initiator p-(chloro-methyljphenyltrimethoxysilane (CPTMS) in combination with a “dummy” initiator phenyltrimethoxysilane (PTMS), acetyl bromid (AcBr), or (3-glycidyloxypropyl)trimethoxysilane (GPTMS), the latter which display an epoxy (epoxide) group suited for further modification by ringopening of the epoxy (epoxide) group. Within the present context, the term “dummy initiator”, “nonpolymerization initiator” or “initiator not initiating polymerization” is a chemical entity which does not initiate surface polymer formation in the presence of an active polymerization catalyst.

[0086] Thus, the presence of polymerization initiators in the polymerization initiator layer may be “diluted” by the simultaneous presence of “dummy” initiators to form a polymerization initiator layer containing polymerization initiators active for surface polymer formation and chemical entities (the “dummy” initiator) not active for surface polymer formation. The “dummy” initiator may be added in a certain percentage together with the polymerization initiator, thus, competing with the polymerization initiator about available attachment sites on the substrate surface. Dilution of the polymerization initiator with a “dummy” initiator may be used to adjust the density of the polymerization initiators on the surface of the substrate, thus, aiding in controlling density (“grafting density”, i.e. the number of surface polymer chains per unit area of the substrate) of subsequently formed surface polymers. Here “grafting” means monoiner-by-monomer propagation of surface polymers from the polymerization initiators. The density of the initiators (both polymerization initiators and non-polymerization / ” dummy” initiators) influences the density of the subsequently formed surface polymer propagated from the polymerization initiator sites. As mentioned above, the density of polymerization initiators is intended to mean the number of polymerization initiators per unit area. Non-limiting examples of suitable percentage ratios (molecular-% (mol%) of polymerization initiator to non-polymerization initiator) may be in the range 100:0 (no nonpolymerization initiator), 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, and 10:90.

[0087] In some instances, a polymerization initiator may be attached to a surface polymer, and a surface polymer formed from the surface polymer-bound polymerization initiators. The surface polymer formed by such procedure is denoted “bottle brush” surface polymer. A suited polymerization initiator is a-bromobutyryl bromide (BiBB). Bottle brush surface polymers may be indicated as, for example, PHEMA-BiBB-PHEMA, meaning that a surface polymer is formed from HEMA monomer, BiBB polymerization initiator is attached to the PHEMA surface polymer, and surface polymer is formed from HEMA monomer from BiBB polymerization initiator. Methods for forming surface polymers are known, among them SI-ATRP (surface-initiated atom transfer radical polymerization), SI-RAFT (surface-initiated reversible-addition fragmentation chain transfer), SI-NMP (surface-initiated nitroxide-mediated polymerization), SI-PIMP (surface-initiated photoiniferter-mediated polymerization), and SI-A(R)GET (surface-initiated activators (regenerated) by electron transfer) ATRP. A review is given in Chem. Rev. 2009, 109, 5437-5527. Other approaches include SET-LRP (single-electron transfer living radical polymerization) and SARA ATRP (supplemental activator and reducing agent atom transfer radical polymerization). These methods may be applied in the formation of surface polymers as described herein.

[0088] When forming surface polymers, polymerization initiators are firstly formed on the surface onto which the surface polymers are to be formed. Secondly, the surface is brought into contact with suitable monomers, catalysts, ligands and optionally a solvent, or suitable monomers, catalyst, ligands, a reducing agent / catalyst activator and optionally a solvent, whereby the surface polymer can form using certain reaction conditions. The polymerization initiators and the monomers are chosen so as to suit the purposes and properties of the resulting surface polymers. Surface polymers may also be formed as layers of surface polymers by repeating the polymeric architecture, e.g., using another starting monomer (block copolymers).

[0089] Among these known procedures for formation of surface polymers, (ARGET) ATRP and SET-LRP are widely used. For the polymerizing chains to propagate, a monomer, a catalyst, a ligand and a solvent are needed. In (ARGET) ATRP and SET-LRP polymerizations, some reactions activate the catalyst, thereby, promoting polymerization, and at the same time, other reactions deactivate the catalyst to impede polymerization. SARA- ATRP and SET-LRP are described, e.g., in https: / 7www. cmu.edu / maty / atrp-how / procedures-for-initiation-of-ATRP / SARA-ATRP-or-SET-LRP.html.

[0090] Both the SET-LRP and (ARGET) ATRP method rely on the formation of a complex between the ligand and a halide formed with a transition metal as specified in the Periodic Table (usually CuCh or CuBn in the case of ARGET ATRP, and Cu(0) in the case of SET-LRP, but other transition metals and halogens may be used). The ARGET ATRP involves a halogen transfer between a dormant halogen capped species, Pn-X and Cu(I)X / L catalyst, resulting in the formation of a propagating radical (Pn radical) and Cu(II)X2. The propagating radical undergoes polymerization with monomers, forming the growing polymer chain. Controlling the ratio between Cu(I)X / L and Cu(II)X2 / 'L in ARGET ATRP allows control of the polymerization itself.

[0091] From WO 2019 / 196999 Al, which is incorporated by reference in its entirety, as if fully set forth herein, an alternative oxygen-tolerant method for forming surface polymers is disclosed. The catalyst / ligand complex described in WO 2019 / 196999 Al is halogen free in so far as the catalyst / ligand complex formed is not complexed with a halogen anion as the catalyst / ligand complex formed is a catalyst oxide. An advantage is that the complex (pre-)formed between the transition metal and the ligand is inactive (i.e., not available for initiating polymerization of the monomer) and furthermore stable (oxygen-insensitive), but the system can be activated “on demand” by a reducing agent / catalyst activator, thus, initiating polymerization and propagation of the surface polymers.

[0092] In the methods described herein, the catalyst may be copper (Cu), iron (Fe) or ruthenium (Ru). It is to be understood that the transition metal, Cu, Fe, Ru, is denoted catalyst when it is complexed with a ligand L. The catalyst may be based on oxides, chlorides or bromides (in some cases also hydrates formed with the metal chloride) and be provided as such in order to form the complex between the ligand and the transition metal. E.g., a solid copper source may be circulated in water with ligand, whereby Cu oxides are liberated and Cu(n) in its catalytically inactive form may complex with the ligand. E.g., CuCh may be added as a salt with the ligand dissolved in a solvent to form the complex between the ligan and the transition metal, Cu. Other catalysts may be those based on Fe, such as FeCls or FeCh, and those based on Ru, such as RuCh and RuCh hydrate.

[0093] The ligand to be used herein may selected from ACV,2VEV”iV’’-pentamethyldiethylene-trianiine (PMDETA), tris[2-(dimethylamino)ethyl]amine (Me6TREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TPMA), 1, 1,4,7, 10, 10-hexametliyltriethylenetetramine (HMTETA), tetramethylethylenediamine (TMEDA), 1,4, 8,1 l-tetramethyl-1,4,8,11-tetraazacyclotetradecane (MetCyclam), and / or 2,2 ’-bipyridyl (BiPy). Other ligands may include 1,4,8, 11 -tetraazacyclo-tetradecane (Cyclam), l,8-dimethyl-l,4,8,l 1-tetraazacyclotetradecane (NfeCyclam), 1,4,7,10-tetraazacyclododecane (Cyclen), and different methylated Cyclen derivatives.

[0094] The ratio of ligand to catalyst in the reaction composition to be applied herein may be m the range 0,001:1 to 1000:1. The ratio of ligand to catalyst in the reaction composition may, in some embodiments, be in the range 0.005:1 to 100: 1, for example 0.13:1, 0.5:1, 1.0: 1, 2.0:1, 3.5:1, 7.5: 1 or 12: 1, In general, an excess amount of ligand as compared to amount of catalyst may be used.

[0095] The catalyst activation may be an oxygen scavenger such as sodium ascorbate (N Asc), ascorbic acid, hydrazine, hydrazine hydrate, sodium hypophosphite, glucose, tin 2-ethylhexanoate, sodium phenoxide, sodium dithionite, a mixture of iron powder and sodium chloride, hydrogen carbonate, citric acid, and pyrogallic acid, as well as mixtures thereof.

[0096] The solvent to be used m the method described herein may be any solvent that provides sufficient solubility of the components of the reaction composition. Suitable solvents include but are not limited to: alcohols (like methanol, ethanol, and isopropanol), dipolar aprotic solvents (for examples, tetra-hydrofuran, methyl acetate, ethyl acetate, butyl acetate, dimethyl sulfoxide, dimethyl formamide), methylene carbonate, ethylene carbonate, propylene carbonate, ethyl lactate alcohol, toluene ionic liquids, supercritical CO2, and water, as well as mixtures thereof. The solvent may be aqueous. The solvent may be selected from methanol (MeOH), ethanol (EtOH), isopropanol (iPrOH), water, and mixtures thereof. Mixtures of methanol, ethanol, and / or isopropanol with water will be suited for some applications. The ratio (volume-% (vol%)) between water and organic solvent may be 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, or 90:10 as well as range therebetween.

[0097] The solvent may solubilize the other components of the reaction composition. Some of the components may be solubilized in the solvent prior to the surface polymer formation and mixed with the remaining components. Thus, any of the monomer, the catalyst and the ligand, and the catalyst activator may be solubilized in the solvent prior to surface polymer formation. Non-limiting ways of mixing include mixing of catalyst, ligand and solvent prior to mixing with catalyst activator optionally solubilized in solvent, or mixing of catalyst, ligand, solvent, and catalyst activator prior to addition of monomer optionally solubilized in solvent, or mixing of catalyst, ligand, solvent, and monomer prior to addition of catalyst activator solubilized in solvent. It is to be understood that “solvent” in the aforementioned cases may include water alone, or a mixture of water and organic solvent. Other ways of mixing of the components of the reaction composition may be envisaged, and, thus, the order of mixing of the components should not be restricted to the disclosure of the Examples.

[0098] The reaction composition as described herein for formation of surface polymers may comprise a buffer. The term “buffer” is defined herein as an agent which, when added to the reaction composition, can within a certain pH range withstand changes in pH when acidic or alkaline substances / components are added to the reaction composition or is formed in the reaction composition. Buffer systems include combinations of a weak acid and its conjugate base, or a weak base and its conjugate acid. Buffers may suitably be prepared as an aqueous solution but may in some cases involve adding a non-aqueous solution or solid / semi-solid formulation to the reaction composition. Non-limiting examples of buffers are carbonate buffer, glycine buffer, citrate buffer, phosphate buffer, acetate buffer, ammonium buffer (ammonium chloride / ammoma), formate buffer, sodium ascorbate / ascorbic acid buffer, and / or zwitterionic buffers. Zwitterionic buffers may comprise Good’s buffers selected from MES, PIPES, MOPS, HEPES, CHES, CAPSO and / or CAPS.

[0099] The reaction composition to be applied herein may in some cases comprise a halide compound for increasing the “livingness” of the polymerization. A “living” polymerization refers to a polymerization where the rate of termination is minor in comparison to the rate of propagation of polymer molecules from the polymerization initiators. As a result, living polymerizations show a more linear relationship between polymer chain length and time. The halide compound to be used herein is a compound capable of providing a halide anion. N on-limiting examples of such compounds are NaCl, NaBr, KC1, KBr, MgCk, MgBn, CaCh, HC1, HBr, LiCl, LiBr, CaBn, as well as combinations thereof. Halide compounds may disassociate in the reaction composition, generating halide anions which may form complexes with and / or bind to catalysts in solution, resulting in an increased concentration of catalyst / ligand-X (X is the halide anion) complexes which are responsible for end-cappmg, and thus deactivating, propagating surface polymer cham-end radicals to deliver alkyl halides. Consequently, the number of propagating surface polymer chain-end radicals at any given time is lowered, which may result in at least the following effects; (1) a lowering of the rate with which polymer molecules grow initially due to a lower number of propagating chains, and (2) a lowering of the rate with which chain termination between two propagating polymer molecule chain-end radicals occur (through recombination or disproportionation), leading to an increased living character of the polymerization. The halide compound may suitably be used in the range of from 0.1 M to 2 M.

[0100] Monomers to be used herein may suitably be used in the range 0,5 vol% to 50 vol%, e.g., 0.5 vol%, 2 vol%, or 10 vol% of a reaction composition.

[0101] The formation of surface polymers may be performed at ambient temperature, at a temperature above ambient temperature, or at a temperature below ambient temperature. The temperature during surface polymer formation may be controlled automatically. The surface polymerization time may vary depending on components of the reaction composition, the targeted a verage dry film thickness of the surface, process optimization, etc.

[0102] The procedures described above for the methods for forming surface polymers may be repeated in order to form block co-polymers by applying two or more different monomers. Accordingly, it is envisaged that each layer or block of surface polymer formed on the substrate may be formed by bringing a desired portion of the surface of a substate into contact with a reaction composition comprising a monomer which may differ from the monomer applied in the first polymerization. Repeating the steps of the methods multiple times may provide formation of multiple layers of surface polymers. In some embodiments, so-called random surface polymer may be formed. Random surface polymer can be formed applying a reaction composition with multiple different monomers. Random surface polymer may be formed either as first surface polymer layer or further surface polymer layer. The surface polymer may possess specific properties obtained through block co-polymers, random polymers, or binary mixed polymer, resulting in a surface polymer with a difference m surface polymer architecture. In such embodiments, the different monomers of block co-polymers, random polymers or binary mixed polymers may contribute with different properties resulting in a surface polymer with a combination of desired properties. Also, forming block co-polymers, random polymers or binary mixed polymers may provide an overall thicker surface polymer, i.e. a surface polymer with higher average dry film thickness. Two or more functional groups (e.g., halogen atoms, hydroxyl groups, or amine groups) can be incorporated, resulting in surface polymers with a unique set of combined properties, each of which is inherent from individual monomers. Formation of block co-polymers, and random polymers are usually formed as a result of a “living” polymerization where the formed surface polymer has viable chain-ends that may initiate further polymerization in subsequent polymerization events.

[0103] As mentioned above, surface polymers may be bottle brush surface polymers. By “bottle brush surface polymers” is meant a surface polymer composed of at least two polymer molecules. Bottle brush surface polymers are formed by forming first polymer molecules from first polymerization initiators attached to at least a portion of a surface of a substrate, attaching second polymerization initiators to the first polymer molecules, and subsequently forming second polymer molecules from second polymerization initiator sites on the first polymer molecules. Third, fourth, fifth and so on polymer molecules may be formed from polymerization initiators bonded to polymer molecules already formed, rather than from polymerization initiators present on the surface of the substrate. Examples of polymerization initiators to be bonded onto polymer molecules include 2-bromoisobutyryl bromide (BiBB), 3-chloropropyltrimethoxysilane (CPTMS), and chloromethyl moieties. In some instances, the polymerization initiator may be “diluted” with a “dummy initiator” (non-polymerization initiator) such as acetyl bromide (AcBr), pivoloyl bromide, or isobutyryl bromide, with no ability to initiate the polymerization. Accordingly, the density of the second, third, fourth and so on polymer molecules may be controlled. The first, second, third, and so on polymer molecules may be copolymers (e.g., block polymers, or random copolymers) as described above.

[0104] The “monomer-by-monomer” approach (“grafting from” approach) for formation of surface polymers offers myriads of monomer types and combinations thereof in forming surface polymers of desired structure, composition, and properties. The methods presented herein have proven sufficiently oxygen insensitive to make possible the polymerization to generally take place under ambient atmospheric conditions, and this offers a flexibility in the design of surface polymers as well as in the preparation of them, including high-volume manufacturing.

[0105] Surface polymers formed on a substrate may be analyzed, e.g., by ellipsometry’. Ellipsometry provides a measurement of the average dry film thickness of the surface polymer across the substrate or a portion of a substrate. Generally speaking, a substrate with a surface polymer (for ellipsometry) is herein considered dry when no visible solvent film, droplets, or residues are observed with the naked eye on the surface of the substrate. Other methods of obtaining a dry substrate may be used, some of which include: withdrawal of the substrate(s) from the reaction composition, followed by rinsing by sonication in Dl-water for 5 minutes, followed by sonication in acetone for 5 minutes, and drying in ambient air 1-30 minutes. In some cases, the substrates may be flushed with acetone after withdrawal from the reaction composition, followed by air-dry mg in an oven at 80 °C for 15 minutes. Still, in some cases, the substrate(s) may be flushed with acetone, then sonicated in acetone for 5 minutes and left to dry at 80 °C for 10 minutes. Alternatively, the substrate(s) may be flushed with iPrOH, then sonicated in isopropanol (iPrOH) for 5 minutes and left to dry under nitrogen flow for 10-30 minutes.

[0106] It is to be understood that by the term “thickness of a surface polymer” or “thickness of a polymer on a surface” is meant the film formed on the substrate, i.e., the surface polymer as defined herein. The thickness is often measured as the dry film thickness by ellipsometry but may be measured by other means such as reflectometry or by measuring a step edge in the coating by atomic force microscopy or profilometry. Generally speaking, a substrate with a surface polymer film is considered dry when no visible solvent film, droplets, or residues are observed on the surface of the substrate. E.g., a substrate may be “dried” by sonication m Dl-water, followed by sonication in a volatile solvent (such as acetone), and air dried at ambient temperature for at least 10 minutes. Measurements such as atomic force microscopy and profilometry demand that a step edge is made in the coating from the outer edge of the coating and all the way to the surface of the substrate, by e.g. scratching. Thus, a targeted surface polymer thickness may be obtained within the applied predefined polymerization time, that is a thickness within +. / - 20%, preferably + / -15% or less, of the average thickness obtained during the multiple surface polymer formation events as determined by diy film thickness of surface polymers. In the dry state, the surface-tethered polymer molecules acquire a conformation between fully collapsed and stretched conformation where the degree of stretching depends on the grafting density.

[0107] Electronic devices have become indispensable in modern society', embedded in everything from personal mobile devices and computing systems to critical infrastructure for communication, data storage, government operations, and financial services. The electronics industry is continuously evolving to meet growing demands for devices that are faster, smaller, more energy-efficient, and more reliable, while also being cost-effective and scalable for mass production. The manufacturing of electronic devices typically involves three major process domains: the frontend, where semiconductor wafers are fabricated; the back-end, where individual dies are separated and tested; and the packaging process. The packaging process, which follows front-end wafer fabrication and back-end die preparation, has become a critical stage in semiconductor manufacturing. Packaging refers to the encapsulation and interconnection of semiconductor dies into usable components. Its primary functions include providing electrical connectivity, mechanical support, thermal management, and environmental protection. Traditional packaging formats - such as Dual In-Line Packages (DIP), Quad Flat Packages (QFP), and Ball Grid Arrays (BGA) - have served these roles effectively in many consumer and industrial applications.

[0108] As device complexity and performance requirements have increased, a specialized subset of packaging known as advanced packaging has emerged. Advanced packaging encompasses a range of technologies designed to enable high-density interconnects, fine-pitch routing, vertical stacking of dies, and heterogeneous integration of multiple functional components (e.g., logic, memory, RF). Techniques such as flip-chip bonding, 2.5D and 3D integration, fan-out wafer-level packaging (FOWLP), and chiplet architectures fall within this domain. These approaches demand materials and processes that support miniaturization, signal integrity, and thermal reliability at increasingly demanding scales.

[0109] A key enabler of advanced packaging is the use of build-up films, which are dielectric layers applied sequentially to form multi-layered substrates. These build-up films allow for the creation of fine-line circuitry and microvias, facilitating high-density interconnects between the semiconductor die and the package substrate. Build-up films provide mechanical support, electrical insulation, and environmental protection, and are critical in forming the redistribution layers (RDLs) that route signals from the die to the package.

[0110] One of the most widely adopted build-up films is Ajinomoto Build-up Film (ABF), a resin-based dielectric material known for its excellent electrical insulation, low dielectric constant, and compatibility’ with fine-pitch designs. ABF is typically used in flip-chip bail grid array (FCBGA) substrates and substrate- like PCBs, where it supports the formation of microvias and thin conductive traces between layers.

[0111] Despite its advantages, the integration of ABF into semiconductor packages presents several materials engineering challenges, particularly in terms of adhesion and mechanical stress. ABF must bond effectively to both copper conductors and inorganic substrates such as glass cores or silicon interposers. These interfaces are prone to delamination, cracking, or warpage, especially under thermal cycling or during high-temperature reflow processes.

[0112] The mismatch in coefficient of thermal expansion (CTE) between ABF and adjacent materials (e.g., copper or glass) can lead to stress accumulation at the interfaces. For example, copper has a relatively high CTE compared to ABF, which can cause tensile stress or shear stress during heating and cooling cycles. Similarly, glass substrates, which have a much lower CTE, may induce compressive stress in the ABF layer, potentially leading to interfacial failure or microcracking.

[0113] To mitigate the above issues, various surface treatments, adhesion promoters, and intermediate layers (such as underfill or modified UBM stacks) are currently employed. However, this adds complexity to the manufacturing process and may not fully eliminate reliability concerns, especially in view of device geometries continuously shrink and layer counts increase.

[0114] Thus, the development of improved build-up film materials, surface modification techniques, and stress-relief architectures remains a key area of innovation in semiconductor packaging.

[0115] The device stack as described herein features several surface polymers having certain reactive functionalities (functional groups as specified above) chemically binding to compatible groups m an epoxy material, thus, improving adhesion between the substrate and the epoxy material. The epoxy material includes non-cured or semi-cured composite materials which are designed to undergo changes including cross-linking upon curing. Reaction / bonding between functional groups of the surface polymer and functional groups in the epoxy material may be established upon heating, heat pressing, lamination, vacuum lamination, and curing as mentioned above. Below, chemical moieties are exemplified which, in the case where one group is represented in a surface polymer and a compatible group is represented in an applied material, may be linked through covalent bonding.

[0116] The chemical binding of functional groups of a surface polymer and functional groups of an epoxy material may be illustrated by the following non-limiting examples: A surface polymer is firstly formed from (hydroxyethyl)methacrylate (HEMA) monomer, yielding a poly((hydroxyethyl)meth-acrylate) (PHEMA) surface polymer. An epoxy material comprising epoxide groups is overlayered, and in a lamination / curmg step, the epoxide groups are ring-opened by reaction with the alcohol functionalities of the PHEMA surface polymer, resulting in covalent bonding between groups by an addition reaction. 4-Vinylaniline (4VA) may be polymerized to form poly(4-vinylaniline) (P4VA) surface polymers, followed by overlaying of an epoxy material comprising epoxide groups. In a subsequent lamination / curmg step, the epoxide groups are ring-opened by the aniline (amine) functionalities of the P4VA surface polymer, resulting in covalent bonding by an addition reaction. Surface polymers of glycidyl methacrylate (GMA) monomer may be formed on a substrate, yielding poly(glycidyl methacrylate) (PGMA) surface polymer, followed by the overlaying of an epoxy material comprising hydroxyl groups. In a subsequent lamination / curing step, the epoxide groups of the PGMA surface polymer are ring-opened upon reaction with the hydroxyl groups of the epoxy material, resulting in covalent bonding by an addition reaction. Surface polymers of glycidyl methacrylate (GMA) monomer may be formed to yield poly(glycidyl methacrylate) (PGMA) surface polymer, followed by overlaying an epoxy material comprising cyanate ester groups. In a subsequent lammation / curing step, the epoxide groups of the PGMA surface polymer ring-open upon reaction with the cyanate ester groups, resulting in covalent bonding by cyclization reactions. The general principle is schematically illustrated in Fig. 3 showing a device stack 200 being formed by overlaying an epoxy material 201 on s substrate 203 having surface polymers 202 grafted on a surface of the substrate 203. To establish a binding between functional groups present in the surface polymer 202 and functional groups present in the epoxy material 201, the overlayered substrate 203 with surface polymer may be heated, heat pressed, laminated, or vacuum laminated, optionally following by a curing step (not shown in Fig. 3). In cases where more than two types of chemically compatible functional groups are present in the surface polymer structure and / or the epoxy material, several bonding modes / chemical reactions may occur in parallel between the surface polymer and the epoxy material.

[0117] Also disclosed herein is a system for forming surface polymers and for forming the device stack.

[0118] Fig. 4 is a non-limiting schematic illustration of a system 100 for forming surface polymers on at least a portion of a substrate. The system 100 comprises a reaction composition container 104 containing the aforementioned reaction composition 105. Container 104 may relate to any vessel or chamber suitable for holding the reaction composition. At least a portion of a polymerization initiator-modified substrate 102 is brought into contact with the reaction composition 105, for example by at least partly immersing a desired surface of substrate 102 into the reaction composition, thereby enabling surface polymers to form on the substrate.

[0119] Optionally, system 100, may comprise one or more further containers, each container comprising different compositions and / or agents for treating the substrate 102, either prior to the substrate being brought into contact with the reaction composition 105, or afterwards. Where substrate 102 has not been pre-treated with a polymerization initiator, then the system 100 may further comprise a container 107 holding a polymerization initiator chemistry 106, thus, forming the polymerization initiator-modified substrate 102 in the container 107; in embodiments the container 107 may be a vacuum oven and the polymerization initiator chemistry 106 may be a substance volatilized in the vacuum oven or introduced into the vacuum oven in vapor form, where an example polymerization initiator chemistry is CPTMS.

[0120] When Fig. 4 relates to an embodiment in which the substrate has been pre-coated with a polymerization initiator. In such embodiments, and as illustrated in Fig. 4, a cleaning container (or containers, as needed) 114 may be provided, comprising a cleaning agent(s) or a cleaning device(s) 116. The cleaning agent(s) / device(s) 116 may be used to clean the surface of substrate 102 prior to bringing it into contact with reaction composition 105 held by the reaction composition container 104. This may be achieved by, at the very least, subjecting at least a portion of the substrate 102 on which it is desired to form surface polymers on, to cleaning procedures in container(s) 114 using cleaning agent / device 116. In this way, any impurities which may interfere with the formation of the surface polymers, are removed from the surface of substrate 102, prior to bringing substrate 102 into contact with the reaction composition 105. System 100 may additionally include a substrate displacement device 103 for bringing the substrate 102 at least partly into contact with the reaction composition 105 held by the reaction composition container 104 for a controlled time to ensure surface polymers form. The displacement device 103 may be used to remove the substrate 102 from the reaction composition 105 following surface polymer formation. Thus, the substrate displacement device 103 may be configured to maintain the surface of substrate 102 at least partly in contact with the reaction composition 105 to enable surface polymers to form on at least a portion of the surface of the substrate, and the substrate displacement device 103 may be configured to maintain the substrate 102 in contact with the reaction composition 105 for a predetermined amount of time.

[0121] In embodiments where the system 100 may comprise two or more containers, such as illustrated in Fig. 4, in addition to bringing substate 102 into contact with the compositions contained by each container, the substrate displacement device 103 is configured to transport substrate 102 to and from each container. For example, as illustrated in Fig. 4, the substrate displacement device 103 is configured to first transport substrate 102 into contact with cleaning agent / device 116 in container 114, and / or a polymerization initiator composition 106 if the substrate is not pre-coated with a polymerization initiator as mentioned previously, held in the polymerization initiator container 107, and subsequently to transport the substrate 102 from the polymerization initiator container 107 to the reaction composition container 104, where the substrate is brought at least partly into contact with the reaction composition 105 held by the reaction composition container 104. In the latter example, the substrate may in embodiments be cleaned between initiator coating and surface polymer formation.

[0122] The substrate displacement device 103 may relate to any device capable of transporting the substrate from one container to another container. For example, the substrate displacement device 103 may relate to a mechanical device. In particular, it is envisaged that the substrate displacement device 103 may comprise any one of: a conveyor system; a programmable mechanical arm or arms; and / or a roll-to-roll processor / mechanism. A conveyor system as used herein may refer to a mechanical system that is used to move a material, such as the substrate, which in embodiments may be in a substrate holder on its own or with other substrates, from one process container to another, typically comprising a movable conveyor, powered by a drive system and having a series of rollers or pulleys that support and guide the belt. In use, the substrate may be placed on the conveyor which passes the substrate through the one or more containers comprised in the system. In this way, as the conveyor is powered, the substrate is passed through the component(s) held by each container within the system. Furthermore, in some embodiments the containers are enclosures in which the reaction composition, or other appropriate wet chemistry, is uniformly applied over the substrate using spray nozzles.

[0123] In some embodiments a programmable mechanical arm, such as a robotic arm, may be used to transport the substrate, which may be in a substrate holder as described above. The programmable mechanical arm, in embodiments, has the capability to move wafer holders horizontally and vertically in and out of containers and from container to container.

[0124] A roll-to-roll processor or mechanism is particularly advantageous for use where the substrate may be flexible and elongated, such as a cable, wire, foil, or any other elongated flexible substrate. Fig. 5 illustrates such an embodiment, m which the substrate displacement device relates to a roll-to-roll processor 118, comprising a sending roll 121, a receiving roll 122 and a plurality of rollers 120. At least some of the rollers 120 and the receiving roll 122 are driven, thereby enabling a flexible elongated substrate 123 to be passed from sending roll 121 through the reaction composition 105 in container 104 to the receiving roll 122. The roll-to-roll mechanism can be utilized as a replacement to the substrate displacement device 103 in Fig. 5 when elongated flexible substrates are being processed.

[0125] In yet further embodiments, at least one of the plurality of containers may comprise an annealing oven for annealing the formed surface polymers. In a similar manner as described previously, the substrate displacement device 103 may be configured to transport the substrate with the formed surface polymers to the annealing oven 109 and to bring the substrate with surface polymers into position for annealing. The annealing oven is equipped with a heating device for annealing the formed surface polymers and the gas environment 111 in the oven may be controlled as needed - for example, to avoid oxidation by using only non-oxidizing gases. In further embodiments, other containers may be added for further processes. For example, a postmodification container may be added for chemically-modifying the surface polymers after formation on the substrate. The chemical-modification container comprising post-modification chemistry as described above. In a similar manner as described previously, the substrate displacement device 103 may be configured to bring at least a portion of the surface polymer coated substrate into contact with the post-modification reagent composition in the post-modification container for a controlled time, wherein the controlled time is sufficient for chemically post-modifying the surface polymers. In another example, a container comprising a device for bonding the substrate with surface polymer and the epoxy material by heating, heat pressing, lamination, or vacuum lamination to form the device stack may be added, and a substrate displacement device may be provided for handling both the substrate with surface polymer and the epoxy material, as would be known by those skilled in the art.

[0126] According to embodiments, a system may comprise: a reaction composition container containing a reaction composition, said reaction composition comprising: a monomer, a catalyst, a ligand, a catalyst activator, and optionally a solvent; a substrate displacement device for bringing at least a portion of a polymerization initiator-modified substrate into contact with the reaction composition in the reaction composition container for a controlled time, wherein the controlled time is sufficient for surface polymers to be formed on the portion of the polymerization initiator-modified substrate, and wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, or wherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, amine, thiol, and amide; and optionally a post-modification container holding a postmodification reagent for post-modifying the formed surface polymer, wherein the substrate displacement device is further configured for bringing at least a portion of the surface polymer coated substrate into contact with the post-modification reagent composition in the post-modification container for a controlled time, and wherein the controlled time is sufficient for post-modifying the surface polymers; and optionally a device for bonding the substrate and the epoxy material by heating, heat pressing, lamination, or vacuum lamination to form the device stack. Furthermore, the substrate displacement device may comprise any one of: a conveyor system, a programmable mechanical arm, or a roll-to-roll mechanism. Furthermore, the system may further comprise a polymerization initiator container containing a polymerization initiator agent, wherein the substrate displacement device is further configured to bring the portion of the substrate for attachment of polymerization initiators into contact with the polymerization initiator agent to form polymerization initiators at the substrate surface, prior to bringing the portion of the polymerization initiator-modified substrate into contact with the reaction composition. Furthermore, the system may comprise a cleaning container, the cleaning container containing a cleaning agent, wherein the substrate displacement device is configured to bring the portion of the polymerization initiator-modified substrate into contact with the cleaning agent prior to, or subsequent to, bringing the portion of the polymerization initiator-modified substrate into contact with the reaction composition; and optionally the substrate displacement device is configured to bring the portion of substrate into contact with the cleaning agent prior to, or subsequent to, bringing the portion of the substrate into contact with the polymerization initiator. Furthermore, the polymerization initiator container may be a vacuum oven. Furthermore, extra containers may be added as needed for rinsing, etc. between processes. The substrate displacement device may be one or more robots or a conveyor system with the capability to move wafer holders horizontally and vertically in and out of containers and from container to container.

[0127] Certain embodiments of the present disclosure are further illustrated by the examples below.

[0128] Examples

[0129] List of chemicals used:

[0130] Throughout the examples, Dl-water refers to tap water deionized using the deionizing equipment Silhorko with M22-F softening plant, RO Bl -2 Reverse Osmosis plant and Silex 2BS mixed bed plant. The quality of the Dl-water is confirmed at least weekly. Dl-water holds a conductivity of less than 0.1 pS / cm, indicating very low presence of ions, below 0.1 mg / L.

[0131] Corning Eagle Glass XG (Eagle glass) 100x100x0.7 mm, 2-side polished was purchased from MH Corporation.

[0132] MSE PRO 100 mm Schott Borofloat 33 Glass Wafer, 500 um thickness, DSP, w / Bevel, primary flat only (BF33) was purchased from MSE Supplies.

[0133] Borofloat 33 Glass Wafer, 8-inch was purchased from MEMC Electronic Materials, Inc. Cu wafer, diameter = 300 mm, 100 A Ta + 1000 A Cu was purchased from Kioxia Corporation. Acetone (>99%) was purchased from Chemsolute.

[0134] Isopropanol (iPrOH) (>99.8%) was purchased from Chemsolute.

[0135] Ethanol (EtOH) (96%) was purchased from KiiltoClean.

[0136] Dimethylformamide (DMF) (99.9%) was purchased from Chemsolute.

[0137] Sodium hydroxide (NaOH) (min. 99.0 %) was purchased from Chemsolute.

[0138] Sulfuric acid (H2SO4) (min. 97 %) was purchased from Chemsolute.

[0139] 4-(Chloromethyl)phenyltrimethoxysilane (CPTMS) (95%) was purchased from Gelest.

[0140] Copper(II) chloride dihydrate (CuCl₂·2H₂O) (>99%) was purchased from Sigma-Aldrich.

[0141] Tris(2-pyridylmethyl)amine (TPMA) (98%) was purchased from Tokyo Chemical Industry.

[0142] Tris[2-(dimethylamino)-ethyl]-amine (Me6TREN) (>98%) was purchased from abcr or Alfa Aesar.

[0143] 2-Hydroxyethyl methacrylate (HEMA) (97 %, <250 ppm MEHQ) was purchased from Sigma-Aldrich.

[0144] Glycidyl methacrylate (GMA) (>97% grade containing <100 ppm MEHQ) was purchased from Sigma-Aldrich.

[0145] Acrylamide (AM) (>98%) was purchased from Sigma- Aldrich.

[0146] Triethyl amine (TEA) (>99%) was purchased from Sigma Aldrich.

[0147] 4-dimethylaminopyridine (DMAP) (>99.0%) was purchased from Tokyo Chemical Industry.

[0148] a-Bromoisobutyryl bromide (BiBB) (98%) was purchased from Sigma Aldrich.

[0149] Sodium hydrogen carbonate (NaHCOs) (min. 99.7 %) was purchased from Chemsolute.

[0150] Sodium carbonate (Na₂CO₃) (anhydrous, min. 99.8 %) was purchased from Chemsolute.

[0151] Sodium ascorbate (NaAsc) (98%) was purchased from Sigma- Aldrich.

[0152] List of equipment used in the Examples:

[0153] “Big sonicator” refers to an ULTRASONIC CLEANER PROCLEAN 28.0 from Ulsonix (40 kHz, 480 W).

[0154] “Sonicator” refers toto a Bandelin Sonorex Super RK100 sonicator (35 kHz ultrasound frequency, 80 W nominal ultrasonic power).

[0155] “Vacuum oven” refers to a Faithful Vacuum Drying Oven-DZ-BCII.

[0156] “Oven” refers to a Binder model FD 56. Ellipsometry’ was measured on a J. A. Woollam M-2000 Ellipsometer. This instrument was set to measure 10 points on each substrate, unless otherwise indicated. Each point was analyzed using a Cauchy model providing a thickness and a Mean Square Error (MSE), the latter referring to the goodness of the fit. Thicknesses are thus given as the average of all measured points on the substrate (average dry film thickness). Unless specifically stated otherwise, 10 data points were obtained on each substrate. Standard deviation is the standard deviation based on the entirety of the measured thicknesses. The standard deviation is an estimate of the homogeneity of surface polymers formed. To obtain detailed datasets of surface polymer thickness from which lateral maps of surface polymer average dry film thickness can be produced, the ellipsometer instrument can be equipped with focusing optics (J. A. Woollam), reducing the beam spot size (the measured area) from 300 μm x 710 μm to 30 μm x 71 μm at a 65 -degree angle of incidence. The much smaller beam size enables measurement of many more points on a substrate, enabling a higher resolution of the surface polymer average dry film thickness.

[0157] Water Contact Angles (WCA) were determined on a Krüss Mobile Surface Analyzer.

[0158] Example 1

[0159] Pre-cleaning of Coming Eagle XG Glass and Schott BOROFLOAT 33 Glass substrates Corning Eagle Glass XG (Eagle glass) 100x100x0.7 mm were cut into 4 sheets of 50x50x0.7 mm substrates, and MSE PRO 100 mm Schott Borofloat 33 Glass Wafer, 500 um thickness (BF33) were cut into 4 sheets of A wafer substrates. Both Eagle glass and BF33 glass were placed in a wafer carrier in a vertical orientation and washed by dipping in iPrOH to remove any adsorbed dust particles and other residues. The substrates were then air-dried in ambient conditions and ambient temperature for at least 2 minutes. Following drying, the substrates were immersed in 5M NaOH solution at a temperature of 60°C and sonicated for 10 minutes in the sonicator. The substrates were then washed by dipping in Dl-water followed by 5-minute sonication in the sonicator in fresh Dl-water. Following sonication, the substrates were dipped in iPrOH followed by 5-minute sonication in the sonicator in fresh iPrOH. Finally, the substrates were dried in the oven at 80°C for 15 minutes.

[0160] Pre-cleaning of 8-inch Borofloat 33 (BF33) Glass substrates

[0161] Borofloat 33 Glass Wafer substrates, 8-inch, were placed in a wafer rack in a vertical orientation throughout the entire cleaning and drying process. The rack with substrates were washed by dipping in iPrOH to remove of any adsorbed dust particles and other residues, and then air-dried at ambient conditions at ambient temperature. Following drying, the substrates were immersed in 5M NaOH solution at a temperature of 60°C and sonicated in the big sonicator for 10 minutes. The substrates were then washed by dipping in Dl-water followed by flush under running tap of Dl-water, before a 5 -minute sonication in the big sonicator in fresh Dl-water. Then the substrates were flushed in iPrOH followed by 5-minute sonication in the big sonicator in fresh iPrOH. Finally, the substrates were dried in an oven set at 80°C for 15 minutes.

[0162] Example 2

[0163] Chemical vapor deposition of 4-( chloromethyl )phenyltrim ethoxy silane (CPTMS) polymerization initiator

[0164] In this example, the procedure for covalently attaching CPTMS polymerization initiators on Eagle Glass and BF33 glass substrates is described.

[0165] Eagle Glass and BF33 glass substrates as specified above were cleaned as described in Example 1 prior to surface modification with CPTMS polymerization initiators using the following method: The substrates were mounted in a wafer carrier in a vertical orientation and were placed in a vacuum oven with 16 vials of 100 pL CPTMS each at approximately 45°C, The gauge pressure was lowered to -1.0 bar, causing the CPTMS to evaporate, and the substrates were left for 150 minutes in the vapor. Thereafter, the wafer carrier containing the substrates was moved to the oven at approximately 80°C for 5 minutes to anneal the formed polymerization initiator layer.

[0166] Chemical vapor deposition of 4-(chloromethyl)phenyltrimethoxysilane polymerization initiator at 100°C

[0167] In this example, the procedure for attaching polymerization initiators on 8-inch BF33 substrates is described.

[0168] 8-inch BF33 glass substrates, cleaned as described in Example 3, were modified with CPTMS polymerization initiators using the following method: The substrates were placed in a wafer rack m a vertical orientation and placed in the vacuum oven with 16 vials of 100 pL CPTMS at 100°C. The gauge pressure was lowered to -1.0 bar during 10 min, causing the CPTMS to evaporate, and the substrates were left for 20 minutes in the vacuum and vapor. Thereafter, the pressure was released during 10 minutes, and the substrates were removed and left for 24 hours (at ambient temperature, ambient pressure) to anneal the formed CPTMS layer.

[0169] Example 3

[0170] Surface polymer (PGMA) formation on Eagle Glass and BF33 substrates

[0171] Eagle Glass substrates and BF33 glass substrates, pre-cleaned as described in Example 1, and subjected to polymerization initiator-modification with CPTMS as described in Example 2.

[0172] The reaction composition for surface polymer formation was prepared as follows (specific components and amounts indicated in Table 1): To a glass container (container A) was added: 1.6 mL catalyst solution (see table 1), 48.4 mL Dl-water, and 41.0 mL. ethanol. In a separate glass container (container B), 400 mg sodium ascorbate (catalyst activator) was dissolved in 1.5 mL Dl-water. In the case of Eagle Glass, 7.5 mL glycidyl methacrylate (GMA) monomer was added to container A followed by addition of the content of container B. After 5 minutes, the complex formed between the catalyst and the ligand was considered activated, and the reaction composition was then ready for surface polymerization on the Eagle Glass substrates. In case of the BF33 substrate, the content of container B was mixed into container A. After 5 minutes, the complex formed between the catalyst and the ligand was considered activated, and 7.5 mL GMA was added. The reaction composition was then ready for surface polymerization on the BF33 substrates.

[0173] Table 1. Reaction composition for surface polymer formation on two types of substrates.

[0174]

[0175] Each series of substrates were placed in a wafer carrier in a vertical orientation and immersed into the reaction composition at minute 0. Minute 0 is defined as 5 minutes after addition of (the solution of) catalyst activator (sodium ascorbate - NaAsc). The substrates were removed from the reaction composition after 10 minutes polymerization time and subsequently cleaned by sonicating for 5 minutes in a sonicator in Dl-water, followed by sonicating for 5 minutes in acetone. After cleaning and drying the substrates (ambient temperature, ambient pressure), the average dry film thicknesses of the formed (collapsed) surface polymers were analyzed using ellipsometry, and the water contact angle (WCA) was determined, see Table 2 below.

[0176] Table 2. Average dry film thickness and water contact angles measured.

[0177]

[0178] The change in WCA results from 66° to 60° confirms that a change in surface free energy has taken place during surface polymer formation. Considered the ellipsometry measurements as well, the inventors concludes that PGMA surface polymers were successfully formed on the substrates.

[0179] Example 4

[0180] Surface polymer (PGMA) formation on 8-inch BF33 Glass substrates

[0181] In a glass container, the catalyst solution was prepared by dissolving CuCl₂·2H₂O (143.1 mg) and TPMA (884.2 mg) in EtOH (73,5 mL) and DI- water (94.5 mL). The catalyst solution was sonicated for 5 minutes in a sonicator to a homogenous solution. To the reaction container was added the catalyst solution (168 mL), Dl-water (5817 mL), EtOH (3570 mL) and GMA monomer (787.5 mL) under magnetically continuous stirring. In a separate container, a solution of NaAsc (42000 mg in 157.5 mL Dl-water) was prepared. The solution of NaAsc was added to the reaction container, and the reaction composition was stirred for an additional 2 minutes, before the magnet was removed and the reaction composition left for 3 minutes to activate the catalyst / ligand complex for surface polymer formation. 4 CPTMS-initiator-modified 8-inch BF33 substrates (pre-cleaned as described in Example 1 and CPTMS modified as described in Example 2) were placed in a wafer rack in a vertical orientation and transferred to the reaction container. The substrates were withdrawn after 10 minutes polymerization time. The substrates were dipped in DI- water and sonicated in DI- water for 5 minutes in a big sonicator. The substrates were flushed with acetone, then sonicated in acetone for 5 minutes in the big sonicator. The substrates were flushed with iPrOH, then sonicated in iPrOH for 5 minutes in the big sonicator. Then, the substrates were dried in an oven at 80°C for 2 minutes. Water Contact Angles were determined, see Table 3.

[0182] Table 3. Water Contact Angles (WCA) of a substrate before and after surface polymer formation.

[0183]

[0184] As observed in Table 3, the WCA of PGMA polymerized BF33 is lower than the WCA of CPTMS-coated BF33, indicating that a surface of higher hydrophilicity is obtained after the described process. This is consistent with the expectation that a PGMA surface polymer, which carries epoxy groups, is more hydrophilic than the CPTMS-modified surface. Thus, the WCA indicates that the PGMA surface polymers were successfully formed from the CPTMS polymerization initiators on the surface of the BF33 substrate.

[0185] Example 5

[0186] Surface polymer (PHEMA) formation on 8-inch BF33 Glass substrates

[0187] In a glass container, a 0.3 M carbonate buffer was prepared by dissolving NaHCO₃ (45.868 g) and Na₂CO₃ (5.725 g) in Dl-water (2 L). In a glass container, the catalyst solution was prepared by dissolving CuCl₂·2H₂O (13.6 mg) and TPMA (84.1 mg) in HEMA (7 mL) and Dl-water (9 ml). The catalyst solution was sonicated for 5 minutes in a sonicator to a homogenous solution. To another glass container (container A) was added: the catalyst solution (16 mL), HEMA (308 mL) and 0.3 M carbonate buffer (660 mL). In a separate container (container B) a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of container B was poured into container A, and the reaction composition was magnetically stirred for 3 minutes. After 3 minutes, the mixture was adjusted to pH 8.8 by addition of H2SO4 (300 uL) during continuously stirring. The mixture in container A was poured into the reaction container. A CPTMS- initiator-modified 8-inch BF33 substrate (pre-cleaned as described in Example 1, and CPTMS modified as described in Example 2) was placed horizontally in the reaction container and withdrawn after 10 minutes polymerization time. The substrate was dipped in Dl-water and a new CPTMS-initiator-modified 8-inch BF33 substrate (pre-cleaned as described in Example 3, and CPTMS modified as described in Example 4) was placed horizontally in the reaction container holding the reaction composition and withdrawn after 10 minutes. This procedure continued for a total number of 4 CPTMS-initiator-modified 8-inch BF33 substrates.

[0188] The substrates were then sonicated in Dl-water for 5 minutes m the big sonicator. The substrates were flushed with acetone, then sonicated in acetone for 5 minutes in the big sonicator. The substrates were flushed with iPrOH, then sonicated in iPrOH for 5 minutes in the big sonicator. The substrates were dried in the oven at 80 °C for 2 minutes. Water Contact Angles (WCA) were determined, see Table 4,

[0189] Table 4. Water Contact Angles (WCA) of substrate before and after surface polymer formation.

[0190]

[0191] As observed in Table 4, the WCA of the PHEMA polymerized BF33 is lower than the WCA of CPTMS-coated BF33, indicating that a surface of higher hydrophilicity is obtained after the surface polymer formation. This is consistent with the expectancy that a PHEMA surface polymer, which carries hydroxyl groups, is more hydrophilic than a CPTMS-modified surface. Thus, the WCA indicates that the PHEMA surface polymers were successfully formed from the CPTMS polymerization initiators on the BF33 substrate.

[0192] Example 6

[0193] Surface polymer (PHEMA) formation on 1x4 inch Eagle glass (EG) substrates of PHEMA

[0194] A 0.6 M carbonate buffer was prepared by dissolving NaHCOs (688.1 g) and Na2COs (85.90 g) in Dl-water (13.5 L) in a glass container. A CuCh solution was prepared by dissolving 1513.9 mg CUCI2 2H2O in 1000 m Dl-water. PHEMA surface polymers were formed from CPTMS polymerization initiators (attached as described in Example 2): In a glass container, TPMA (126.15 mg) was dissolved in HEMA (10.5 mL), 13.5 mL CuCh solution was added, and the solution was sonicated for 5 minutes in a sonicator to form a homogenous solution. 24 mL of this solution was added to another glass container (container A), together with HEMA (462 mL), 0.6 M carbonate buffer (495 mL), and Dl-water (495 mL). In a separate container (container B) a solution of NaAsc (6 g in 22.5 mL Dl-water) was prepared. The content of container B was poured into container A, and the reaction composition was magnetically stirred for 2 minutes. After 2 minutes, the reaction composition was adjusted to pH 8.8 by addition of H2SO4 (0,75 mL) during continuously stirring. The reaction composition in container A was poured into the reaction container, 5 CPTMS-initiator-modified 1x4 inch Eagle glass substrates (pre-cleaned as described in Example 1, and CPTMS modified as described in Example 2) were placed horizontally in the reaction container and withdrawn after 2, 5, 10, 20, and 40 minutes, respectively. Then, the substrates were dipped in Dl-water, followed by sonicating in Dl-water for 5 minutes in a big sonicator. The substrates were flushed with acetone, then sonicated in acetone for 5 minutes in the big sonicator. The substrates were air-dried at ambient temperature and ambient pressure. The average dry film thickness was determined using profilometry as shown in Fig. 6. Furthermore, the substrates were analyzed by Grazing Angle IR (GA-IR) (Perkin Elmer Spectrum Two FT-IR spectrometer with grazing angle module from PIKE Technologies Vee MaxIII (measurement angle 65deg, 32 scans, large mask) and the recorded spectra is shown in Fig. 7. In Fig. 7, “ALT” denotes “arbitrary unit”.

[0195] Table 5, Surface polymer average dry film thicknesses determined by profilometry and C=O peak area as determined by GA-IR.

[0196]

[0197] GA-IR is a technique generally suitable for determining the thickness of thinner films (here surface polymers) in the nanometer to micrometer range. From the results shown in Table 5 and the GA-IR spectra shown in Fig. 7, it was concluded that there seems to be a correlation between the average dry film thickness as determined by profilometry and the intensity of the C=O band in the GA-IR spectra. The PHEMA surface polymer is rich in C=O bonds. Since the number of C=O bonds correspond to the number of repeating units in the polymer chain, the intensity of the C=O peak measured by GA-IR (Fig. 7) is indicative of, and correlates with, the polymer coating thickness determined by profilometry. Accordingly, the correlation between the C=O peak intensity and the coating thickness enables the estimation or verification of the polymer film thickness directly from GA-IR measurements. This relationship is demonstrated in Fig. 8, which show's a linear dependence between the C=O peak intensity and the surface polymer average dry film thickness.

[0198] Example 7

[0199] Surface polymer (PHEMA or PGMA) formation on 8-inch BF33 glass wafer substrates

[0200] A 0.6 M carbonate buffer was prepared by dissolving NaHCO₃ (688.1 g) and Na₂CO₃ (85.90 g) m Dl-water (13.5 L) in a glass container. A CuCl₂ solution was prepared by dissolving 1513.9 mg CuCl₂·2H₂O in 1000 mL Dl-water.

[0201] In the polymerizations described below, a “witness” Si wafer substrate (one for the PHEMA surface polymer formation, and one for the PGMA surface polymer formation) was included with the BF33 substrates. As average dry film thickness measurements by ellipsometry cannot be determined with sufficient accuracy, the witness substrate serves the purpose of confirming that the surface polymer formation has taken place as expected.

[0202] PHEMA surface polymers w’ere formed on 8-inch BF33 glass w’afer substrates from CPTMS polymerization initiators (CPTMS-modified as described in Example 2). In a glass container, TPMA (883 mg) was dissolved in HEMA monomer (73.5 mL). 94.5 mL of the CuCl₂ solution prepared above was added, and the mixture was sonicated for 5 minutes in a sonicator to form a homogenous solution. 168 mL of this solution was added to another glass container (Container A) together with HEMA monomer (3234 mL), 0.6 M carbonate buffer as prepared above (3465 mL), and Dl-water (3465 mL). In a separate container (Container B) a solution of NaAsc (42.00 g in 157.5 mL DI-water) was prepared. The content of Container B was poured into Container A, and the reaction composition was magnetically stirred for 2 minutes. After 2 minutes, the reaction composition was adjusted to pH 8.8 by addition of H2SO4 (3.5 mL) during continuously stirring. The reaction composition in container A was poured into a reaction container. 9 CPTMS-initiator-modified 8-inch BF33 substrates (pre-cleaned as described in Example 1) were placed horizontally in the reaction container and withdrawn after 40 minutes of polymerization time. The substrates were immediately dipped in DI- water, followed by sonicating in Dl-water for 5 minutes in a big sonicator. The substrates were flushed with acetone, then sonicated in acetone for 5 minutes in the big sonicator. The substrates were air-dried at ambient conditions (ambient temperature, ambient pressure). Water Contact Angle (WCA) was determined for one BF33 glass substrate, see Table 6.

[0203] PGMA surface polymers were formed on 8-inch BF33 glass substrates from CPTMS polymerization initiators as described in Example 2. In a glass container, TPMA (884.6 mg) was dissolved in EtOH (73.5 mL), and 94.5 mL CuCl₂ solution (prepared as described above) was added.

[0204] 168 mL of this solution was added to another glass container (Container A) together with GMA monomer (787.5 mL), Dl-water (5817 mL), and EtOH (3570 mL). In a separate container (Container B) a solution of NaAsc (42.00 g in 157.5 mL Dl-water) was prepared. The content of Container B was poured into Container A, and the reaction composition was magnetically stirred for 2 minutes. After 5 minutes, the reaction composition in Container A was poured into a reaction container and was ready for surface polymer formation. 3 CPTMS-modified 8-inch BF33 glass substrate were placed horizontally in the reaction container and withdrawn after 40 minutes polymerization time. Then the substrates were immediately post-cleaned by dipping in Dl-water, followed by sonication for 5 minutes in DI water, flushing with acetone, and sonication for 5 minutes in acetone, before being left to dry (ambient temperature, ambient pressure). Water Contact Angle (WCAs) was determined for one BF33 glass substrate, see Table 6.

[0205] Table 6. Water Contact Angle (WCA) of one BF33 glass substrate with PHEMA surface polymers, and one BF33 glass substrate with PGMA surface polymers. The average dry film thickness of the surface polymer was determined by ellipsometry on the Si “witness” wafers included with the BF33 substrates in respect of the PHEMA and the PGMA surface polymerizations.

[0206]

[0207] As observed in Table 6, the WCA of the PHEMA surface polymer BF33 substrate is slightly lower than that of PGMA. Film thicknesses of “witness” substrates Si- CPTMS -PHEMA and Si-CPTMS-PGMA are shown in Table 6, where it is seen, that surface polymers of -120 nm are achieved for both Si- CPTMS -PHEMA and Si-CPTMS-PGMA, thus, confirming the successful surface polymer formation.

[0208] Example 8

[0209] Surface polymer formation on 8-inch BF33 glass substrates

[0210] In this example, the following surface polymers were prepared on 8-inch BF33 glass substrates: BF33-CPTMS-PHEMA (9 substrates),

[0211] BF33-CPTMS-PGMA (3 substrates),

[0212] BF33-CPTMS-PHEMA-BiBB-PHEMA (3 substrates), and

[0213] BF33-CPTMS-PHEMA-BiBB-PGMA (3 substrates).

[0214] In the above, “CPTMS” indicates that the BF33 glass substrates were modified with CPTMS polymerization initiators as described in Example 2. In the above, “-PHEMA-“ indicates that a first polymerization was initiated via the CPTMS polymerization initiators and surface polymers of HEMA monomer was formed. In the above, “-BiBB-“ indicates that the PHEMA surface polymer was modified with BiBB (a-bromoisobuyryl bromide) polymerization initiators, attached to the PHEMA surface polymer. In the above, “-BiBB-PHEMA“ and “-BiBB-PGMA“ indicate that a second polymerization was initiated via the BiBB polymerization initiators with either HEMA monomer or GMA monomer. Thus, these latter surface polymers were denoted “bottle brush surface polymers”.

[0215] On 6 BF33 8-inch wafer substrates, PHEMA surface polymers were formed by the procedure described in Example 7. Second polymerization initiators BiBB were attached to the PHEMA surface polymer by the following procedure: To a reaction container, DMF (9776 mL), TEA (76.7 mL) and DMAP (6.42 g) were sonicated until DMAP was dissolved. BiBB (651 mL) was added, and the solution was stirred with a spoon. The 6 8-inch BF33 substrates with PHEMA surface polymers were placed horizontally in the reaction container and withdrawn after 10 minutes. Then the substrates were post-cleaned by sonication for 5 minutes in DCM, flushed with acetone, and sonicated for 5 minutes in acetone, before being left to dry (ambient temperature, ambient pressure). After cleaning and drying, the substrates (now modified with the BiBB polymerization initiators, “BF33-CPTMS-PHEMA-BiBB”) were stored in the dark until being used for subsequent PHEMA or PGMA surface polymer formation (bottle brush formation).

[0216] In the surface polymerizations described below, a “witness” Si wafer substrate was included with the BF33 substrates. As average dry film thickness measurements by ellipsometry cannot be determined with sufficient accuracy on BF33 glass, the witness substrate serves the purpose of confirming that the surface polymer formation has taken place as expected.

[0217] To form bottle brushes of PHEMA, a second polymerization of HEMA was initiated via the BiBB polymerization initiator (BF33-CPTMS-PHEMA-BiBB) by the PHEMA polymerization procedure described m Example 7. 3 CPTMS-PHEMA-BiBB-modified 8-inch BF33 substrates were placed horizontally in the reaction container and withdrawn after 10 minutes polymerization time. Then the substrates were post-cleaned by dipping in Dl-water, followed by sonication for 5 minutes in DI water, flushing with acetone, and sonication for 5 minutes in acetone, before being left to dry (ambient temperature, ambient pressure). Water Contact Angle (WCA) of the BF33 substrate and the average dry thickness on the Si substrate were determined in respect of the Si substrate, see Table 7.

[0218] To form bottle brushes of PGMA, a second polymerization of GMA was initiated via the BiBB polymerization initiators (BF33-CPTMS-PHEMA-BiBB) by the PGMA polymerization procedure described in Example 7. 3 CPTMS-PGMA-BiBB-modified 8-inch BF33 substrates were placed horizontally in the reaction container and withdrawn after 40 minutes polymerization time. Then the substrates were immediately post-cleaned by dipping in Dl-water, followed by sonication for 5 minutes in DI water, flushing with acetone, and sonication for 5 minutes in acetone, before being left to dry (ambient temperature, ambient pressure). Water Contact Angle (WCA) of the BF33 glass substrate, and the average dry film thickness were determined on the Si substrate, see Table 7.

[0219] Table 7. Water Contact Angle (WCA) of the BF33 substrate and the average dry film thickness determined on the Si substrate by ellipsometry on the witness substrates.

[0220]

[0221] As observed in Table 7, the WCA of the BF33-CPTMS-PHEMA-BiBB-PHEMA substrate and the BF33-CPTMS-PHEMA were similar (see Table 6, Example 7, and Table 7, this example). This was also the case for the BF33-CPTMS-PHEMA-BiBB-PGMA and BF33-CPTMS-PGMA (Table 6 and Table 7). Thus, it may be concluded that for the WCA, the “outer” surface polymer has more influence on the measured WCA.

[0222] The average dry film thicknesses in respect of the Si “witness” wafer substrates, Si-CPTMS-PHEMA, Si-CPTMS-PHEMA-BiBB-PHEMA, Si-CPTMS-PGMA, and Si-CPTMS-PHEMA-BiBB-PGMA, respectively, are shown in Table 6, Example 7 and in Table 7, this example, respectively. In case of the bottle brush surface polymers (Table 7), it is clearly seen, that thick surface polymers >1.2 pm were achieved following the second polymerizations of HEMA monomer and GMA monomer, respectively, with the reasoning that the surface polymerization on glass and Si wafers are comparable. The presence of the thick surface polymers on the BF33 glass substrates were also confirmed optically as the glass substrates became opaque / white instead of clear, following the surface polymerizations. This is consistent with the surface polymer being dense, thus, the refraction of the light is altered.

[0223] Example 9

[0224] Alleviating buildup of stress in Glass-ABF laminates through interfacial surface polymer layers This example illustrates how surface polymers on 8-inch (-500 micron thick) Schott BF33 glass wafer substrates alleviate buildup of stress in the glass substrate during stress testing when laminated with ABF (type ABF GX92).

[0225] In advanced packaging applications, multiple layers of buildup film (such as ABF) and copper (Cu) are sequentially applied to form the redistribution layer (RDL) As a model and to mimic the RDL scenario and the stress exerted on and in the glass, 4 layers of ABF were laminated on 8-inch glass wafer substrates having surface polymers on the glass wafer substrate (that is, between the glass wafer substrate and the first layer of ABF). After each ABF lamination, the wafer substrates were subjected to thermal curing and a thermal annealing, respectively. After completing 4 cycles of lamination, thermal curing, and annealing the wafer substrates were subjected to Thermal Cycling tests. Thermal Cycling tests are a part of reliability testing in the industry.

[0226] The 8-inch BF33 glass wafer substrates were coated with surface polymers according to the procedure described in Example 7 (CPTMS-PHEMA, and CPTMS-PGMA) and Example 8 (CPTMS-PHEMA-BiBB-PHEMA, and CPTMS-PHEMA-BiBB-PGMA). The substrates with surface polymers are recited in Table 8.

[0227] Two reference BF33 glass wafer substrates were included in the test. Reference 1 (1 (ref.)), as indicated in Table 8, was without surface polymer, whereas Reference 2 (2 (ref.)) was coated with APTES (3-aminopropyltrimethoxysilane) in a silane vapor deposition process. A BF33 glass wafer substrate was firstly cleaned with O?. plasma to descum / clean the surface. The substrate was then placed m an air-tight chamber with a small amount of APTES precursor, and finally the airtight chamber was transferred to a normal convection oven and heated at 70°C for 20 minutes. By this procedure, the APTES vaporized and coated the substrate surface evenly.

[0228] 4 layers of 8-inch ABF GX92 were laminated onto each of the glass wafer substates 1-4, and Reference 1 and 2, respectively. One ABF layer, on each substrate, at a time, was laminated onto the substrates. In total, the lamination procedure was performed 4 times on each substrate. The lamination procedure is summarized in Table 9. For substrate 1 (ref.), steps 1, 2, 5 and 6 were performed. For substrate 2 (ref), steps 1-6 were performed. For substrates 1-4, steps 1, 5, and 6 were performed.

[0229] After each ABF lamination step, the substrates were firstly thermally cured to fully cure the ABF laminate in a VWR Gravity Convection Oven at 100°C for 60 minutes followed by a ramp up to 180°C during 30 minutes and finally cooling down to room temperature (approximately 35 minutes) by turning off the oven.

[0230] Following each thermal curing step, thermal annealing at 180°C for 60 minutes was performed. The thermal annealing was performed to mimic the industry’s ABF reflow process typically following copper deposition in the RDL fabrication sequence. In this example, no copper was deposited, however, the reflow anneal of the BF33 glass wafer substrates resembles the stress change of induced by the industry’s RDL sequence.

[0231] Table 8. Substrates of BF33 glass wafers with surface polymers each laminated with 4 layers of ABF GX92 for stress testing. Substrate 1 (ref.) is blank BF33 glass wafer substrate with 4 layers of ABF GX92. Substrate 2 (ref.) is BF33 glass wafer substrate coated with APTES and laminated with 4 sheets of ABF GX 92.

[0232]

[0233] Table 9. ABF GX92 lamination procedure.

[0234]

[0235]

[0236] The substrates indicated in Table 8 were stress tested m accordance with the JEDEC standard in a Espec BTZ4200 Thermal Cycling Chamber, following the JESD22-A104 directions (temperature cycling between -40°C and +125°C with a cycle duration of 1 hour, ramp rate of 15°C / minute, and a dwell time of 15 minutes at each temperature extreme.

[0237] Each substrate indicated in Table 8 was subjected to a number of thermal cycles as described above and analyzed by scanning acoustic microscopy (SAM) using a Sonoscan C-SAM D9000 Scanning Acoustic Microscope (Transducer: 230 MP (230 MHz); Scan Area: Full Wafer: 213 mm 160 mm or Quadrant: 132 mm 101.4 mm; Scan Resolution: Full Wafer: 1024 * 960 pixels or Quadrant: 1024 x 960 pixels). The SAM images are shown in Fig. 9 through Fig. 28 before thermal cycling and following an indicated number of cycles.

[0238] Fig, 9 shows Reference substrate 1 (1 (ref.)) with 4 sheets of ABF GX92 before thermal cycling. Fig.

[0239] 10 shows substrate 1 (ret) following 100 thermal cycles. As seen in Fig. 10, a crack was observed across the substrate (white line from top to bottom, marked with black arrow). Fig. 11 shows substrate 1 (ref.) following 300 thermal cycles. At this stage, substrate 1 (ref.) was broken into two pieces. Furthermore, the whiter area (top of picture, marked with white arrow) is a result of warpage (bending of the substrate), indicating a heavy stress buildup. Fig. 12 shows substrate 1 (ref.) following 500 thermal cycles. Now, the warpage (bending, marked with white arrow) has become more severe, and no further thermal cycling was performed as substrate 1 (ref.) was considered too damaged.

[0240] Fig. 13 and Fig. 14 show substrate 2 (ref.) before thermal cycling. As can be seen from Fig. 14 (upper left area), an edge crack and a small chip (marked with white arrows) are visible before thermal cycling. Fig. 15 shows substrate 2 (ref.) following 100 thermal cycles. A new crack originating from the existing chip defect had appeared spanning to the free edge within the same quadrant. Fig. 16 shows substrate 2 (ref.) following 250 thermal cycles. A defect was observed (marked with a white arrow). Fig. 17 shows substrate 2 (ref.) following 450 thermal cycles. Bifurcation originating from the existing edge crack has appeared (marked with a white arrow). Fig 18 shows substrate 2 (ref.) following 1000 thermal cycles. The already observed defect (see Fig. 16) had worsened. It was concluded that although the AI’TES layer provided some alleviation of stress buildup, the alleviation was not substantial and still resulted in failure.

[0241] Fig. 19 shows substrate 3 before thermal cycling. As seen from Fig. 19, the ABF GX92 laminate is without visible defects. Fig. 20 shows substrate 3 following 100 thermal cycles. As can be seen from Fig. 20, no defects have emerged. Fig. 21 shows substrate 3 following 250 thermal cycles. As can be seen from Fig. 21, no defects have emerged. Fig. 22 shows substrate 3 following 450 thermal cycles. As can be seen from Fig. 22, no defects or cracks have emerged. Fig. 23 shows substrate 3 following 1000 thermal cycles. As can be seen from Fig. 23, substrate 3 still does not show any cracks or defects, and the surface polymer on substrate 3 was able to alleviate the stress buildup to an excellent degree.

[0242] Fig. 24 shows substrate 4 before thermal cycling. As can be seen from Fig. 24, the ABF GX92 laminate is without any visible defects. Fig. 25 shows substrate 4 following 100 thermal cycles. As seen from Fig, 25, no visible defects have emerged. Fig. 26 shows substrate 4 following 250 thermal cycles. As seen from Fig. 26, no visible defects have emerged. Fig. 27 shows substrate 4 following 450 thermal cycles. As seen from Fig, 27, no cracks had emerged, however, a white area was seen in the upper right, however, no apparent warping was observed by inspecting with the naked eye. In Fig.

[0243] 28, substrate 4 following 1000 cycles is shown. In Fig, 28, no cracks have emerged. Thus, it was concluded that the surface polymer on substrate 4 alleviated stress buildup to an excellent degree. In order to investigate whether the excellent protection against stress buildup in the glass and / or ABF GX92 laminate observed on substrate 3 and substrate 4, respectively, could be due to loss of adherence / bonding between the ABF GX92 and the glass wafer substrates after thermal cycling, the thermally cycled substrates (glass / ABF laminates) were subjected to a stud pull test.

[0244] Substrates I through 4 (after thermal cycling) were diced into approximately 3x3 cm pieces. Paint from the backside was removed, using acetone (technical grade, >99.0%) and a paper towel. A steel support (grade AISI304, dimensions 45x45x6 mm) and a dolly (010 mm) was attached to the backside and frontside respectively of the substrate pieces using PermaBond EP 718 Epoxy 2K structural adhesive. Immediately before assembly, all mating surfaces was rubbed using brown Scotch-Brite™, followed by whipping with isopropanol (HPLC grade, >99.8%) and delicate task wipes. The assembly was then placed in an oven at 60°C for 1 hour, after which the oven was turned off and the substrates allowed to cool in the oven. The substrates were left to rest time for 48 hours from assembly to testing in accordance with technical datasheet of the adhesive used.

[0245] Each of the substrates were tested using a Defelsko PosiTest AT-A, yielding a measure of adhesive strength. Results of the test are shown in Table 10.

[0246] Table 10. The pull-off strength achieved on the four different substrates, 1 (Ref), 2 (Ref.), 3, and 4, respective, with a minimum of 3 samplings per substrate.

[0247]

[0248] As seen from Table 10, all pull-off strengths were above 40 MPa. No substrates failed at the interface between ABF GX92 and the BF33 glass wafer, meaning that adhesion was intact in all cases after thermal cycling. The failure was observed either cohesively in the structural epoxy (PermaBond EP 718 Epoxy 2K) on the dolly side or on the support side. Thus, it was concluded that the BF33 glass wafer substrates effectively and strongly bonded the ABF GX92 even after thermal cycling. The bonding was mediated by the surface polymers, which in one end was covalently attached to the glass substrate, and in the other end had functional groups able to form covalent bonds to the epoxy matrix in the ABF. Thus, the alleviation of stress buildup (no thermal cycling induced cracks or defects) observed for substrates 3 and 4, respectively, was concluded to be related to the presence of surface polymer between the BF33 glass wafer substrate and the ABF 92GX.

[0249] Example 10

[0250] Surface polymer (PFIEMA) formation on Cu substrates

[0251] Cu wafer substrates, diameter 300 mm, were cut into pieces of 50x50x0.7 mm and placed in a wafer rack in a vertical orientation throughout a cleaning and drying process. The rack with substrates was washed by dipping in iPrOH to remove of any adsorbed dust particles and other residues, and, then dried in the oven at 80°C for 2 minutes. Following drying, the substrates were immersed in 1% H2SO4 aqueous solution and left for 5 minutes. The substrates were then washed by dipping in Dl-water followed by flushing under running tap of Dl-water, before a 1 -minute dip in fresh DI- water. Then the substrates were flushed in iPrOH followed by 1 -minute dip in fresh iPrOH. Finally, the substrates were dried in the oven at 80°C for 2 minutes.

[0252] Following drying, the substrates were subjected to polymerization initiators attachment according to the following procedure: The substrates were placed in a wafer rack in a vertical orientation and placed in a vacuum oven set at 100°C with 16 vials of each 100 pL CPTMS. The gauge pressure was lowered to -1.0 bar during 10 minutes, causing the CPTMS to evaporate, and the substrates were left for 20 minutes in the vacuum and vapor. Thereafter, the pressure was released during 10 minutes, and the substrates were removed and left for 24 hours to anneal the formed CPTMS layer on the substrates.

[0253] Surface polymers were formed on the CPTMS Cu substrates according to the following procedure: To a glass container (Container A) was added catalyst solution (16 mL prepared from MeeTREN (76 pL), Dl-water (15.924 mL), and Cu(II) (324 mg / L, obtained from a solid copper source by stirring or otherwise mixing prior to mixture with ligand and Dl-water)), Dl-water (805 mL), EtOH (89 mL) and HEMA monomer (75 mL). In a separate container (Container B) a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A, and the reaction composition was left for 5 minutes to activate the reaction composition for surface polymer formation. The mixture in Container A was poured into a reaction container. 4 CPTMS-initiator-modified Cu substrates were placed in a wafer rack in a vertical orientation and were transferred to the reaction container holding the reaction composition. The substrates were withdrawn after 40 minutes polymerization time. The substrates were dipped in EtOH, flushed with Dl-water and sonicated in Dl-water for 5 minutes in a sonicator. Then the substrates were flushed with acetone and sonicated in acetone for 5 minutes in the sonicator. The substrates were considered dry following completion of this procedure. The average dry film thicknesses of the formed (collapsed) surface polymers were analyzed using ellipsometry and the results are shown in Table 11.

[0254] Table 11. Average dry film thicknesses measured on the 4 substrates.

[0255]

[0256] As can be seen from Table 11, PHEMA surface polymers having an average dry film thicknesses were obtained following the 40 minutes polymerization time. It is expected that the surface polymers formed on the Cu substrate will have stress accommodating properties as described in Example 9. Example 11

[0257] Surface polymer formation (PGMA) on Cu substrates

[0258] 4 Cu substrates were cut, pre-cleaned and CPTMS-modified as described in Example 10. Surface polymers were formed on the substrates according to the following procedure: To a glass container (Container A) was added a added catalyst solution (16 mL prepared from MeeTREN (76 pL), DI-water (15,924 mL), and Cu(II) (324 mg / L, obtained from a solid copper source by stirring or otherwise mixing prior to mixture with ligand and DI-water)), DI-water (484 mL), EtOH (410 mL) and GMA monomer (75 mL). In a separate container (Container B) a solution of NaAsc (4000 mg in 15 mL DI-water) was prepared. The content of Container B was poured into Container A, and the reaction composition was left for 5 minutes to activate the reaction composition for surface polymer formation. The reaction composition in Container A was poured into a reaction container. 4 CPTMS -initiator-modified Cu substrates were placed in a wafer rack in a vertical orientation and were transferred to the reaction container and withdrawn after 10 minutes polymerization time. The substrates were flushed with DI-water and sonicated in DI-water for 5 minutes in a sonicator. Then the substrates were flushed with acetone and sonicated in acetone for 5 minutes in the sonicator. After completion of this procedure, the substrates were considered dry. The average dry film thicknesses of the formed (collapsed) surface polymers were analyzed using ellipsometry and the results are shown in Table 12.

[0259] Table 12. Average dry film thicknesses of surface polymers on the 4 substrates.

[0260]

[0261] As can be seen from Table 10, PGMA surface polymers were successfully formed on the 4 Cu substrates. It is expected that the surface polymers formed on the Cu substrate will have stress accommodating properties as described in Example 9.

[0262] Example 12 Surface polymer (PAM) formation on Cu substrates

[0263] Cu substrates were cut, pre-cleaned and CPTMS -modified as described in Example 10. Surface polymers were formed on the substrates according to the following procedure: To a glass container (container A) was added a catalyst solution (3.2 mL) prepared from MeeTREN (76 pL), Dl-water (15.924 mL), and Cu(II) (324 mg / L, obtained from a solid copper source by stirring or otherwise mixing prior to mixture with ligand and Dl-water), DI-water (96.8 mL), EtOH (82 mL) and AM monomer (12000 mg). In a separate container (Container B) a solution of NaAsc (800 mg in 3 mL Dl-water) was prepared. The content of Container B was poured into Container A, and the reaction composition was left for 5 minutes to activate the reaction composition for surface polymer formation. The reaction composition in container A was poured into a reaction container. 4 CPTMS-initiator-modified Cu substrates were placed on the bottom of the reaction container (front side upwards) and withdrawn after 60 minutes polymerization time. The substrates were dipped in Dl-water and sonicated in Dl-water for 5 minutes in a sonicator. Then the substrates were flushed with acetone and sonicated in acetone for 5 minutes in the sonicator. The substrates were considered dry following completion of this procedure. The average dry film thicknesses of the formed (collapsed) surface polymers were analyzed using ellipsometry and the results are shown in Table 13 below.

[0264] Table 13. A verage dry film thicknesses of surface polymers on the 4 substrates.

[0265]

[0266] As can be seen from Table 11, PAM surface polymers were successfully formed on the substrates following the 60 minutes polymerization time. It is expected that the surface polymers formed on the Cu substrate will have stress accommodating properties as described in Example 9. List of reference numerals

[0267] 100 System

[0268] 102 Substrate

[0269] 103 Substrate displacement device 104 Reaction composition container 105 Reaction composition

[0270] 106 Container

[0271] 107 Polymerization initiator chemistry 109 Annealing oven

[0272] 114 Cleaning container

[0273] 116 Cleaning agent / device

[0274] 118 Roll-to-roll processor

[0275] 120 Roller

[0276] 121 Sending roll

[0277] 122 Receiving roll

[0278] 123 Flexible elongated substrate 200 Device stack

[0279] 201 Epoxy material

[0280] 202 Surface polymer

[0281] 203 Substrate

Claims

Claims1. A device stack comprising:a substrate with a first surface,a surface polymer on at least a portion of the first surface, anda layer of epoxy material over the first surface of the substrate,whereinthe surface polymer comprises functional groups for bonding to epoxide groups m the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, orthe surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide.

2. A device stack according to claim 1, wherein the substrate is a glass material or a copper material.

3. A device stack according to claim 1, wherein the epoxy material comprises an epoxide component and an alcohol component, an ester component, or a cyanate ester component.

4. A device stack according to claim 3, wherein the epoxy material is of Ajinomoto Build-up Film (ABF) GX series, GL series, GZ series, or GY series.

5. A device stack according to claim 1, wherein the surface polymer comprises poly (hydroxy ethyl methacrylate) (PHEMA), poly(acrylamide) (PAM), poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), poly(4-vinylaniline) (P4VA), poly(2-aminoethyl methacrylate) (PAEM), post-modified poly(glycidyl methacrylate) (PGMA), or post-modified polystyrene (PSt).

6. A device stack according to claim 1, wherein the surface polymer comprises poly(glycidyl methacrylate) (PGMA) and / or poly(hydroxy ethyl methacrylate) (PHEMA).

7. A device stack according to claim 1, wherein the device stack is formed by heating, heat pressing, lamination, or vacuum lamination.

8. A device stack according to claim 7, wherein the device stack is subjected to a curing process.

9. A device stack comprising:a substrate with a first surface,a surface polymer on at least a portion of the first surface, anda layer of epoxy material over the first surface of the substrate,wherein the surface polymer is formed by:providing a substrate,exposing the substrate to a polymerization initiator,exposing the substrate to a reaction composition comprisinga monomer,a catalyst,a ligand,an activator, andoptionally a solvent, andoptionally post-modifying the surface polymer on the substrate, andwherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, orwherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide.

10. A device stack according to claim 9, wherein the substrate is a glass material or a copper material.

11. A device stack according to claim 9, wherein the epoxy material comprises an epoxide component and an alcohol component, an ester component, or a cyanate ester component.

12. A device stack according to claim 11, wherein the epoxy material is of Ajinomoto Build-up Film (ABF) GX series, GL series, GZ series or GY series.

13. A device stack according to claim 9, wherein the monomer is selected from hydroxy ethyl methacrylate (HEMA), acrylamide (AM), acrylic acid (AA), methacrylic acid (MAA), 4-vinylaniline (4VA), 2-aminoethyl methacrylate (AEM), glycidyl methacrylate (GMA), and styrene (St).

14. A device stack according to claim 9, wherein the catalyst is derived from copper (Cu), iron (Fe) or ruthenium (Ru).

15. A device stack according to claim 9, wherein the ligand is selected from / VyV,. V’, Ar” Ar”-pentamethyldiethylene-triamine (PMDETA), tris[2-(dimethylamino)ethyl]amine (Me6TREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TPMA), 1,1,4,7,10,10-hexamethyl-triethylenetetramine (HMTETA); tetramethylethylenediamine (TMEDA), 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (Me4Cyclam), and / or 2,2’ -bipyridyl (BiPy).

16. A device stack according to claim 9, wherein the catalyst activator is selected from sodium ascorbate, ascorbic acid, hydrazine, hydrazine hydrate, sodium hypophosphite, glucose, tin 2-ethylhexanoate, sodium phenoxide, sodium dithionite, a mixture of iron powder and sodium chloride, hydrogen carbonate, citric acid, and pyrogallic acid, as well as mixtures thereof.

17. A device stack according to claim 9, wherein the solvent is selected from methanol, ethanol, isopropanol, water, and mixtures thereof.

18. A method of preparing a surface polymer for a device stack according to any one of claims 1 to 8 comprisingproviding the substrate, wherein polymerization initiators are covalently bound to a surface of the substrate,exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand, an activator, and optionally a solvent to form surface polymers on the substrate,wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, orwherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide.

19. A method according to claim 18, wherein the surface polymer is post-modified.

20. A method according to claim 18, wherein the monomer is selected from hydroxyethyl methacrylate (HEMA), acrylamide (AM), acrylic acid (AA), methacrylic acid (MAA), 4-vinylaniline (4VA), 2-aminoethyl methacrylate (AEM), glycidyl methacrylate (GMA), and styrene (St).

21. A method according to claim 18, wherein the catalyst is derived from copper (Cu), iron (Fe) or ruthenium (Ru).

22. A method according to claim 18, wherein the ligand is selected from N, N, N’, N”, N”-pentamethyldiethylene-triamine (PMDEIA), tris[2-(dimethylamino)ethyl]amine (Me6TREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TPMA), 1,1,4,7,10,10-hexa-methyltriethylenetetramine (HMTETA); tetramethylethylenediamine (TMEDA), 1,4, 8, 11 -tetramethyl- 1,4, 8,11 -tetraazacyclotetradecane (Me4Cyclam), and / or 2,2’-bipyridyl (BiPy).

23. A method according to claim 18, wherein the catalyst activator is selected from sodium ascorbate, ascorbic acid, hydrazine, hydrazine hydrate, sodium hypophosphite, glucose, tin 2-ethylhexanoate, sodium phenoxide, sodium dithionite, a mixture of iron powder and sodium chloride, hydrogen carbonate, citric acid, and pyrogallic acid, as well as mixtures thereof.

24. A method according to claim 18, wherein the solvent is selected from methanol, ethanol, isopropanol, water, and mixtures thereof.

25. A method of preparing device stack according to any one of claims 1 to 8 comprisingproviding the substrate, wherein surface polymers are present on at least a portion of the surface of the substrate, andwherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and the functional groups are selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, orwherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide,providing the epoxy material, andbonding the substrate and the epoxy material by heating, heat pressing, lamination, or vacuum lamination.

26. A method according to claim 25, wherein the substrate is a glass material or a copper material.

27. A method according to claim 25, wherein the epoxy material comprises an epoxide component and an alcohol component, an ester component, or a cyanate ester component.

28. A method according to claim 29, wherein the epoxy material is an Ajinomoto Build-up Film (ABF) GX series, GL series, GZ series, or GY series.

29. A method according to claim 25, wherein the surface polymer comprises poly(hydroxyethyl methacrylate) (PHEMA), poly(acrylamide) (PAM), poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), poly(4-vinylaniline) (P4VA), poly(2-aminoethyl methacrylate) (PAEM), post-modified poly(glycidyl methacrylate) (PGMA), or post-modified polystyrene (PSt).

30. A method according to claim 25, wherein the surface polymer comprises poly(glycidyl methacrylate) (PGMA), or poly(hydroxy ethyl methacrylate) (PHEMA).

31. A method according to claim 25, wherein the device stack is formed by heating, heat pressing, lamination, or vacuum lamination.

32. A method according to claim 25, wherein the device stack is subjected to a curing process.

33. A method of preparing device stack according to any one of claims 1 to 8 comprising providing the substrate, wherein initiators are covalently bound to a surface of the substrate, exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand, an activator, and optionally a solvent to form surface polymers on the substrate,wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, orwherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide,optionally post-modifying the surface polymer formed on the substrate,providing the epoxy material, andbonding the substrate and the epoxy material by heating, heat pressing, lamination, or vacuum lamination.

34. A method according to claim 33, wherein the substrate is a glass material or a copper material.

35. A method according to claim 33, wherein the epoxy material comprises an epoxide component and an alcohol component, an ester component, or a cyanate ester component.

36. A method according to claim 35, wherein the epoxy material is an Ajinomoto Build-up Film (ABF) GX series, GL series, GZ series, or GY series.

37. A method according to claim 33, wherein the monomer is selected from hydroxy ethyl methacrylate (HEMA), acrylamide (AM), acrylic acid (AA), methacrylic acid (MAA), 4-vinylaniline (4VA), 2-aminoethyl methacrylate (AEM), glycidyl methacrylate (GMA), and polystyrene (St).

38. A method according to claim 33, wherein the catalyst is derived from copper (Cu), iron (Fe) or ruthenium (Ru).

39. A method according to claim 33, wherein the ligand is selected from N, N, N’, N”, N”~ pentamethyldiethylene-triamine (PMDETA), tris[2-(dimethylamino)ethyl]amine (Me6TREN), tris(2-aminoethyljamine (IREN), tris(2-pyridylmetliyl)amine (TPMA), 1,1,4,7,10,10-hexa-methyltriethylenetetramine (HMTETA); tetramethylethylenediamine (TMEDA), 1,4,8,11-tetra-methyl-1,4,8,11 -tetraazacyclotetradecane (MteiCyclam), and / or 2,2’ -bipyridyl (BiPy).

40. A method according to claim 33, wherein the catalyst activator is selected from sodium ascorbate, ascorbic acid, hydrazine, hydrazine hydrate, sodium hypophosphite, glucose, tin 2-ethylhexanoate, sodium phenoxide, sodium dithionite, a mixture of iron powder and sodium chloride, hydrogen carbonate, citric acid, and pyrogallic acid, as well as mixtures thereof,41. A method according to claim 33, wherein the solvent is selected from methanol, ethanol, isopropanol, water, and mixtures thereof.

42. A system for forming surface polymers on a substrate for a device stack according to any one of claims 1 to 8, the system comprising:a reaction composition container containing a reaction composition, said reaction composition comprising:a monomer,a catalyst,a ligand,a catalyst activator, andoptionally a solvent,a substrate displacement device for bringing at least a portion of a polymerization initiator-modified substrate into contact with the reaction composition in the reaction composition container for a controlled time,wherein the controlled time is sufficient for surface polymers to be formed on the portion of the polymerization initiator-modified substrate,wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, orwherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide,43, A system for forming a device stack according to any one of claims 1 to 8, the system comprising:a reaction composition container containing a reaction composition, said reaction composition comprising:a monomer,a catalyst,a ligand,a catalyst activator, andoptionally a solvent,a substrate displacement device for bringing at least a portion of a polymerization initiator-modified substrate into contact with the reaction composition in the reaction composition container for a controlled time,wherein the controlled time is sufficient for surface polymers to be formed on the portion of the polymerization initiator-modified substrate,wherein the surface polymer comprises functional groups for bonding to epoxide groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, orwherein the surface polymer comprises epoxide groups for bonding to functional groups in the epoxy material and selected from one or more of the types of groups: hydroxyl, carboxylic acid, amine, thiol, cyanate ester, and amide, and optionallya post-modification container holding a post-modification reagent for post-modifying the formed surface polymer,wherein the substrate displacement device is further configured for bringing at least a portion of the surface polymer coated substrate into contact with the post-modification reagent composition inthe post-modification container for a controlled time; and wherein the controlled time is sufficient for post-modifying the surface polymers, and optionallya device for bonding the substrate and the epoxy material by heating, heat pressing, lamination, or vacuum lamination to form the device stack.44, A system according to claim 42 or 43, wherein the substrate displacement device comprises anyone of:a conveyor system,a programmable echanical arm, ora roll-to-roll mechanism.45, A system according to any one of claims 42 to 44, further comprising a polymerization initiator container containing a polymerization initiator agent, wherein the substrate displacement device is further configured to bring the portion of the substrate for attachment of polymerization initiators into contact with the polymerization initiator agent to form polymerization initiators at the substrate surface, prior to bringing the portion of the polymerization initiator-modified substrate into contact with the reaction composition.

46. A system of any one of claims 42 to 45 further comprising a cleaning container, the cleaning container containing a cleaning agent, wherein the substrate displacement device is configured to bring the portion of the polymerization initiator-modified substrate into contact with the cleaning agent prior to, or subsequent to, bringing the portion of the polymerization initiator-modified substrate into contact with the reaction composition, and optionallythe substrate displacement device is configured to bring the portion of substrate into contact with the cleaning agent prior to, or subsequent to, bringing the portion of the substrate into contact with the polymerization initiator.

47. A system of claim 45, wherein the polymerization initiator container is a vacuum oven.

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