Electroless deposition of metal on surface polymer films on substrate surfaces

Abstract

The present disclosure relates to the depositing of metals on and within surface polymer films that are covalently bonded to the substrate comprised in a device structure and to the electroless deposition of metals on such surface polymer films.

Description

[0001] Electroless Deposition of Metal on Surface Polymer Films on Substrate Surfaces

[0002] Cross-Reference to Related Applications

[0003] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 653,138, titled “Electroless Deposition of Metal on Polymer Brush Films on Substrate Surfaces,” filed May 29, 2024, the entire contents of which are incorporated by reference herein.

[0004] Field

[0005] The present disclosure relates to the depositing of metals on and within surface polymer films and to the electroless deposition of metals on such surface polymer films.

[0006] Background

[0007] Electroless copper metal deposition on dielectric layers, such as glass, polymer, composites, etc., is an important step for the fabrication of various electronic devices. Conventional methods rely on surface roughening of the dielectric material before palladium metal seed deposition for catalyzing electroless deposition of a copper metal film; the roughening is used to assure mechanical interlocking of the electroless copper metal film with the dielectric layer. However, the surface roughness of the dielectnc layer can be detrimental to fabrication of fine lines and features. Other approaches rely on lower surface roughness in combination with incorporating chemical functionalities beneficial to Palladium metal ion coordination and Palladium seeding either into polymer structures directly, or by creating a self-assembled monolayer (SAM). SAM formation is usually done by surface treatment with organosilanes. Nevertheless, smoothening of the surface and increased reliance on the specific chemical functionalities of SAM can be detrimental to adhesion of the electroless metal to the dielectric layer. There is a need for better processes and device architectures for providing electroless metal films on dielectric layers.

[0008] Summary

[0009] In an aspect of the disclosure, a device structure is provided, the device structure comprising a surface polymer film formed on a substrate, the surface polymer film comprising polymer molecules covalently bonded to polymerization initiation sites on the substrate, and at least one first metal deposited on and within the surface polymer film. The device structure may further comprise a second metal deposited on and within the surface polymer film. The device structure may further comprise a metal layer formed on the surface polymer film by an electroless deposition process, the metal layer comprising the second metal, wherein the at least one first metal catalyzes the electroless deposition of the second metal. The at least one first metal may catalyze the electroless deposition of the second metal upon activation of the at least one first metal.

[0010] In aspect of the disclosure, a device structure is provided, the device structure comprising a surface polymer film formed on a substrate, the surface polymer film comprising polymer molecules covalently bonded to polymerization initiation sites on the substrate, at least one first metal, and a second metal. The device structure may further comprise a metal layer formed on the surface polymer film by an electroless deposition process, the metal layer comprising the second metal, wherein the at least one first metal catalyzes the electroless deposition of the second metal. The at least one first metal may catalyze the electroless deposition of the second metal upon activation of the at least one first metal.

[0011] In the device structures defined above, the at least one first metal may be palladium (Pd). In the device structures defined above, the second metal may be copper (Cu). In the device structures defined above, the substrate may comprise glass, silicon, a dielectric material, a ceramic, a composite material, metal, or a polymer. In the device structure defined above, the surface polymer film may have a thickness in the range of from 100 nm to 2 pm.

[0012] The device structure may be such, wherein the surface polymer film is formed on at least a surface of the substrate by providing the substrate, exposing the substrate to a polymerization initiator to obtain polymerization initiator sites on the substrate, and exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand, an activator, and optionally a solvent. The the catalyst of the reaction composition may be obtained from Cu, Fe or Ru. The ligand of the reaction composition may be selected from AOVA A''". '"'-pentamethyldiethylene-triamine (PMDETA), tris[2-(dimethylamino)ethyl]amine (MeeTREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TP MA), 1,1,4,7,10, 10-hexamethyltri ethylenetetramine (HMTETA), tetramethylethylenediamine (TMEDA), 1 ,4,8, 11 -tetramethyl- 1 ,4,8, 11 -tetraazacyclotetradecane (Me-tCyclam), and / or 2,2’-bipyridyl (BiPy). The the activator of the reaction composition may be selected from sodium ascorbate (NaAsc), ascorbic acid (Asc), hydrazine, hydrazine hydrate, sodium thiosulfate, sodium sulfite, sodium dithionite, glucose, glucose with GOx. and / or pyrogallic acid. The reaction composition may further comprise a buffer. The reaction composition may further comprise a halogen salt. The reaction composition may further comprise a surfactant. The reaction composition may further comprise a polyquatemium compound. The polymerization initiator may be selected from ?-(chloromethyl)phenyltrimethoxy silane (CPTMS), 2-bromoisobutyryl bromide (BiBB), and chloromethyl (CM) moiety. The surface polymer film may comprise polymer molecules of poly(2 -hydroxy ethyl methacry late) (PHEMA), poly(glycidyl methacrylate) (PGMA), poly(n-butyl methacrylate) (PBuMA), poly(tert-butyl methacrylate) (PtBMA), poly(benzyl methacrylate) (PBnzMA). poly(2-ethylhexyl methacrylate) (PEHMA), poly(2-hydroxyethyl acrylate) (PHEA), and polystyrene (PSt), or a combination thereof.

[0013] In an aspect of the disclosure, a method for preparing a device structure is provided, the method comprising providing a substrate having a surface polymer film comprising polymer molecules on at least a surface of the substrate, and exposing the substrate to at least one solution of a first metal to deposit the first metal on and within the surface polymer film. The method may further comprise exposing the substrate to a solution of a second metal to deposit the second metal on and within the surface polymer film. The method may further comprise depositing, by an electroless deposition process, a metal layer comprising the second metal, wherein the at least one first metal catalyzes the electroless deposition of the second metal, and thermally annealing the device structure. The at least one first metal may catalyze the electroless deposition of the second metal upon activation of the at least one first metal.

[0014] In an aspect of the disclosure, a method for preparing a device structure, the method comprising providing a substrate having a surface polymer film comprising polymer molecules on at least a surface of the substrate, exposing the substrate to at least one solution of a first metal to deposit the first metal on and within the surface polymer film, exposing the substrate to a solution of a second metal to deposit the second metal on and within the surface polymer film, depositing, by an electroless deposition process, a metal layer comprising the second metal, wherein the at least one first metal catalyzes the electroless deposition of the second metal, and thermally annealing the device structure. The method may be such, wherein the first metal catalyzes the electroless deposition of the second metal upon activation of the at least one first metal. The at least one first solution may comprise palladium (Pd). The at least one first solution may comprise NazPdCU. The second metal may be copper (Cu). The second metal may be provided in the solution of the second metal as CuSCk The substrate comprises glass, silicon, a dielectric material, a ceramic, a composite material, or a polymer. The surface polymer film may have a thickness in the range of from 100 nm to 2 pm. In the method, the surface polymer film may be formed on at least a surface of the substrate by providing the substrate, exposing the substrate to a polymerization initiator to obtain polymerization initiator sites on the substrate, and exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand, an activator, and optionally a solvent. The catalyst of the reaction composition may be obtained from Cu, Fe or Ru. The ligand of the reaction composition may be selected from A / A / r'.Ar. A''"-pentamethyldiethylene-triamine (PMDETA), tris[2-(dimethylamino)ethyljamine (MeeTREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TP MA), 1,1, 4, 7, 10,10-hexamethyltri ethylenetetramine (HMTETA), tetramethylethylenediamine (TMEDA), 1,4, 8,1 l-tetramethyl-1,4,8,11-tetraazacyclotetradecane (Me4Cyclam), and / or 2,2’ -bipyridyl (BiPy). The activator of the reaction composition may be selected from sodium ascorbate (NaAsc), ascorbic acid (Asc), hydrazine, hydrazine hydrate, sodium thiosulfate, sodium sulfite, sodium dithionite, glucose, glucose with GOx, and / or pyrogallic acid. The reaction composition may further comprise a buffer. The the reaction composition may further comprise a halogen salt. The reaction composition may further comprise a surfactant. The reaction composition may further comprise a polyquatemium compound. The polymerization initiator may be selected from p-(chloromethyl)phenyltrimethoxy silane (CPTMS), 2-bromoisobutyryl bromide (BiBB), and chloromethyl (CM) moiety. The surface polymer film may comprise polymer molecules of poly(2 -hydroxy ethyl methacrylate) (PHEMA), poly(glycidyl methacrylate) (PGMA), poly(n-butyl methacrylate) (PBuMA), poly(tert-butyl methacrylate) (PtBMA). poly(benzyl methacrylate) (PBnzMA). poly(2-ethylhexyl methacrylate) (PEHMA), poly(2-hydroxyethyl acrylate) (PHEA), and polystyrene (PSt), or a combination thereof.

[0015] In an aspect of the disclosure, a system for forming a device structure is provided, the system comprising a first container containing a reaction composition for forming a surface polymer film from polymerization initiator sites on at least a portion of a surface of a substrate, at least one second container containing a solution of a first metal for depositing the first metal on and within the surface polymer film, at least one third container containing a solution for reducing the first metal deposited on and within the surface polymer film, at least one fourth container containing a solution for activating the first metal deposited on and within the surface polymer film, a fifth container containing an electroless solution of a second metal for depositing, by an electroless procedure, the second metal on and within the surface polymer film, and a substrate displacement device, wherein the substrate displacement device brings at least a portion of the substrate with polymerization initiator sites into contact with the reaction composition in the first container for a first controlled time, wherein the first controlled time is sufficient for forming the surface polymer film from the polymerization initiator sites, and wherein the substrate displacement device brings at least a portion of the substrate with surface polymer film into contact with the solution in the at least one second container for a second controlled time, wherein the second controlled time is sufficient for depositing the first metal on and within the surface polymer film, wherein the substrate displacement device brings at least a portion of the substrate with surface polymer film and first metal into contact with the solution in the at least one third container for a third controlled time, wherein the third controlled time is sufficient for reducing the first metal in and within the surface polymer film, wherein the substrate displacement device brings at least a portion of the substrate w ith surface polymer film and first metal into contact with the solution in the at least one fourth container for a fourth controlled time, wherein the fourth controlled time is sufficient for activating the first metal deposited on and within the surface polymer film, and wherein the substrate displacement device brings at least a portion of the substrate with surface polymer film and first metal into contact with the solution in the fifth container for a fifth controlled time, wherein the fifth controlled time is sufficient for depositing, by an electroless deposition process, a second metal on and within the surface polymer film. The system may comprise one or more additional containers for rinsing the substrate. The system may comprise a further container containing a polymerization initiator for forming polymerization initiator sites on at least portion of a surface of the substrate. The system may comprise a further container containing a cross-linking agent for cross-linking the polymer molecules of the surface polymer film, wherein the substrate displacement device brings at least a portion of the substrate with surface polymer film into contact with the cross-linking agent in the further container for a further controlled time, wherein the further controlled time is sufficient to cross-link the polymer molecules in the surface polymer film. The cross-linking of the polymer molecules of the surface polymer film is before depositing of the first metal, or after depositing of the first metal. The system may comprise an oven for thermally annealing the device structure. The first metal may be palladium (Pd), and the second metal may be copper (Cu).

[0016] Description of the Drawings

[0017] 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:

[0018] Fig. 1 illustrates the "grafting to” concept schematically.

[0019] Fig. 2 illustrates the ‘'grafting from” concept schematically.

[0020] Fig. 3 shows a schematic cross-sectional representation of a device structure with a surface polymer film 350, including polymer molecules 330 and functional groups 340 suitable for coordination with a metal catalyst, formed on a substrate 310 from polymerization initiation sites 320.

[0021] Fig. 4 shows a schematic cross-sectional representation of the device structure of Fig. 3 with the addition of metal catalyst 460 coordinated with the functional groups 340 in Fig. 3.

[0022] Fig. 5 shows a schematic cross-sectional representation of the device structure of Fig. 4 with the addition of metal deposited by an electroless (Eless) process, the electroless metal being deposited both in (570) and on (575) the surface polymer film 350 of Figs. 3 and 4.

[0023] Fig. 6 is a process flow overview for the fabrication and testing of devices according to embodiments of the disclosed matter.

[0024] Fig. 7 is a detailed process flow for the electroless (Eless) metal deposition process.

[0025] Fig. 8 shows a thermal anneal temperature profile.

[0026] Fig. 9 shows a schematic representation of a system for forming device structures according to embodiments of the present invention.

[0027] Fig. 10 shows peel test data for electroless (Eless) copper (Cu) on a PHEMA surface polymer film on an Eagle Glass substrate.

[0028] Fig. 11 shows peel test data for electroless (Eless) copper (Cu) on a PGMA surface polymer film on an Eagle Glass substrate using both 3M GT (upper plot) and 3M VHB tape (lower plot), where peeling starts around 2.5 cm for GT tape and around 2.8 cm for VFIB tape.

[0029] Fig. 12 shows peel test data for electroless (Eless) copper (Cu) on a PGMA surface polymer film on an Eagle Glass substrate with no observed peeling where the electroless process had increased time in activation and reduction baths compared with the substrates for which data is shown in Fig. 12.

[0030] Fig. 13 Schematic illustration of the stack for stud pull testing consisting of a dolly 1310, epoxyglue 1320. copper layer 1330, surface polymer film 1340, glass substrate 1350, and backing substrate 1360, see Example 15.

[0031] Fig. 14 shows an Xray image of the through-glass vias (TGV) substrate of Example 13. The four die sets are top left: 50 micron / pitch 150, top right: 100 micron / pitch 150, bottom left: 50 micron / pitch 150, and bottom right: 100 micron / pitch 300, see Example 17.

[0032] Fig. 15 is a zoom of top right: 100 micron / pitch 150 of Fig. 14. Eless copper deposited along the inside of the TGV VIA walls on and in the surface polymer film is seen as dark curved lines, see Example 17. Fig. 16 is a zoom of top left: 50 micron / pitch 150 of Fig. 14. Electroless (Eless) copper (Cu) deposited along the inside of the TGV VIA walls on and in the surface polymer film is seen as dark curv ed lines, see Example 17.

[0033] Fig. 17 shows a FIB SEM image of the VIA substrate of Example 17. The dark areas are the VIAs (100 micron VIAs, BF33 glass with a thickness of 400 pm).

[0034] Fig. 18 shows details of selection 1 of Fig. 17.

[0035] Fig. 19 shows details of selection 2 of Fig. 17.

[0036] Fig. 20 shows details of selection 3 of Fig. 17.

[0037] Fig. 21 shows details of selection 4 of Fig. 17.

[0038] Fig. 22 shows details of selection 5 of Fig. 17.

[0039] Fig. 23 shows a FIB SEM image of the upper part of the through-glass via (TGV) substrate of Example 18 with PHEMA-BiBB-PHEMA surface polymer film and with electroless (Eless) copper (Cu) deposited.

[0040] Fig. 24 shows a FIB SEM image of the middle part of the through-glass via (TGV) substrate of Example 18 with PHEMA-BiBB-PHEMA surface polymer film and with electroless (Eless) copper (Cu) deposited.

[0041] Fig. 25 shows a FIB SEM image of the lower part of the through-glass via (TGV) substrate of Example 18 with PHEMA-BiBB-PHEMA surface polymer film and with electroless (Eless) copper (Cu) deposited.

[0042] Fig. 26 is a zoom of the upper left comer of the middle glass pillar of the TGV substrate shown in Fig. 23, showing both surface polymer film and deposited electroless (Eless) copper (Cu).

[0043] Fig. 27 is a zoom of the right side of the middle glass pillar of the TGV substrate shown in Fig.

[0044] 24, showing both surface polymer and deposited electroless (Eless) copper (Cu).

[0045] Fig. 28 is a zoom of the lower right comer of the second glass pillar from the right of the TGV substrate shown in Fig. 25, showing both surface polymer and deposited electroless (Eless) copper (Cu).

[0046] Detailed Description

[0047] In aspects of the present disclosure, a device structure may comprise a surface polymer film formed on a substrate, the surface polymer film comprising polymer molecules covalently bonded to polymerization initiation sites on the substrate, and at least one first metal, deposited on and within the surface polymer film. The device structure may comprise a second metal deposited on and within the surface polymer film.

[0048] The device structure may comprise a metal layer formed on the surface polymer film by an electroless deposition process, the metal layer formed on the surface polymer film comprising the second metal, where the at least one first metal catalyzes the electroless deposition of the second metal. The at least one first metal may catalyze the electroless deposition of the second metal upon activation of the least one first metal.

[0049] In some aspects, the device structure may comprise a surface polymer film formed on a substrate, the surface polymer film comprising polymer molecules covalently bonded to polymerization initiation sites on the substrate, at least one first metal, and a second metal. The first metal may be deposited on and within the surface polymer film. The device structure may further comprise a metal layer formed on the surface polymer film by an electroless deposition process, the metal layer comprising the second metal, wherein the at least one first metal catalyzes the electroless deposition of the second metal. The at least one first metal may catalyze the electroless deposition of the second metal upon activation of the least one first metal.

[0050] The device structure may be subjected to annealing one or more times during formation. By way of example, annealing make take place post-surface polymer film formation, post-deposition of the at least one first metal, and / or post-electroless deposition of the second metal. In some cases, annealing may only take place after the electroless deposition. Temperatures suited for annealing may depend on the surface polymer film, the uptake and layering of the at least one first metal and the second metal. Annealing temperatures may be reached following a temperature gradient. Cooling the device structure may also be according to a temperature gradient. Non-limiting examples of maximum annealing temperatures (when the temperature has reached the final annealing temperature) are between 150°C and 350°C, such as 200°C, 250°C, and 300°C.

[0051] Such a device structure is illustrated in Figs. 3-5, which figures also provide insight into the fabrication of such devices. Fig. 3 shows a schematic cross-sectional representation of a device structure with a surface polymer film 350. including polymer molecules 330 and functional groups 340 suitable for coordination with the at least one first metal, formed on a substrate 310 from polymerization initiation sites 320. Fig. 4 shows a schematic cross-sectional representation of the device structure of Fig. 3 with the addition of at least one first metal 460 coordinated with the functional groups 340 in Fig. 3. Fig. 5 shows a schematic cross-sectional representation of the device structure of Fig. 4 with the addition of second metal deposited by an electroless process, the electroless metal being deposited both in (570) and on (575) the surface polymer film 350 of Fig. 3 and Fig. 4.

[0052] A general process for preparing a device structure as described herein is shown in Fig. 6. As a first step, a clean substrate is provided 601. Then polymerization initiators sites are formed on the substrate surface (or on a portion of the substrate surface) 602. In a next step, polymer molecules are formed from polymerization initiator sites, making a surface polymer film on the substrate surface (or on aportion of the substrate surface) 603. Optionally the polymer molecules (or a portion of the polymer molecules) making up the surface polymer film may be cross-linked 604. By cross-linking some of the functional groups on the polymer molecules may be bound to each other. Cross-linking may happen internally in the individual polymer molecules or to adjacent polymer molecules. In step 605, a metal is deposited on and within the surface polymer film, followed by an activation (sensitization) of the deposited metal. Further cross-linking may take place following depositing and activating the metal on and within the surface polymer film 606. Step 606 is optional and is independent of whether some of the polymer molecules have been cross-linked in step 604. In step 608, electroless metal is deposited in and on the surface polymer film, the electroless depositing of metal being catalyzed by the presence of metal in and on the surface polymer film. The formed device structure is annealed in step 609. In step 610, the electroless metal deposited is subjected to a tape peel test.

[0053] Another general process for preparing a device structure as described herein is shown in Fig. 7. A substrate with surface polymer film is provided 701, and the at one least first metal is deposited on and within the surface polymer film (sensitization step) 702, followed by a substrate rinse with deionized water 703. Then the deposited at least one first metal is reduced in a reducing bath (reduction step) 704, followed by a substrate rinse in deionized water 705. Then, the at one least first metal is activated in an accelerator step 706, before the second metal is deposited on and within the surface polymer film in step 707. The at least one first metal catalyzes the depositing of the second metal. The depositing is followed by a substrate rinse with deionized water and a substrate drying with nitrogen gas 708. The sensitization step comprises depositing a seeding layer of the at least one first metal (seeds of the at least one first metal) within and on the surface polymer film. In the sensitization step 702, at least one first metal ions are deposited by interaction with the surface polymer film, e.g., by coordination of at least one first metal ions with functional groups on the surface polymer film, oxidation of functional groups by reactive at least one first metal species to form new functional groups on the surface polymer film that can bind or coordinate at least one first metal ions, reduction of some of ions of at least one first metal to at least one first metal clusters. A combination of these pathways is also envisaged. In the reduction step 704, the at least one first metal ions are reduced to at least one first metal. In the accelerator step 706, a chemical substance is used to deposit second metal on and within the surface polymer film. In step 707, the second metal is deposited by an electroless method.

[0054] The at least one first metal may be palladium (Pd). titanium (Ti), tantalum (Ta), cobalt (Co), or ruthenium (Ru). The second metal may be copper (Cu). In some aspects, the at least one first metal may be palladium (Pd), and the second metal may be copper (Cu).

[0055] The at least one first metal deposited on and within the surface polymer may also be denoted ■‘seeds of the at least one first metal” or ‘'at least one first metal seeds”.

[0056] According to aspects of the present disclosure, the surface polymers are formed on at least a portion of a surface of a substrate. 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 unpattemed. 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 glued together, 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 w ith 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, InP, dielectric material, ceramic, composite, as wells as layered and patterned structures thereof. Substrates may have any form and shape, be elongated, be hollow, have protrusions or recesses, etc.

[0057] The device structure as defined herein may be applied in electronic devices. In this disclosure, the term “electronic device” is intended to include devices that operate by controlling electron flow. Included are circuit elements (like capacitors, resistors, transistors, and metallic connections arranged or coupled together to serve a function). Also included are integrated circuits (IC) die (e.g., microprocessor, and memory), Printed Circuit Boards (PCBs) configured to electrically and / or mechanically connect the IC die to other circuits / structures. and Ball Grid Arrays (BGA). Electronic devices also include optical display devices that operate using light, lasers, etc. Electronic devices are generally found in a broad range of products, including communication devices, computers, various consumer products, networks, aviation, industrial controllers, and automotive to mention a few.

[0058] Semiconductor or electronic devices may generally be manufactured using a front-end process (making of transistors), a back-end process (making of interconnects among the transistors and with external connections) and a packaging process (making of connections among multiple chips and components and to external systems with “encapsulations” or packaging suitable for integration into external systems). Such processes are generally known in the art. The processes may potentially involve hundreds of steps where a wafer containing a plurality of semiconductors or dies may be layered or inserted with dopants such as phosphorous, arsenic (N-type), and boron (P-type) among other materials or metals through a photomasking, an ionic implantation, athermal annealing process, a diffusion, metal and other material depositions, photolithography-based patterning, an etching process, wet and dry cleaning, etc. The layers on the plurality of semiconductors may be interconnected to each other through interconnections, such as VIAs and contacts or through lateral interconnections, such as metal lines. The final layers on the plurality of semiconductors’ surfaces on the wafer may include bond pads to electrically expose the respective semiconductors’ I / Os (back-end) to a package substrate or another semiconductor or die. Fabrication methods that are analogous to those described for the front-end process (deposition, patterning, etching, planarization, cleaning, etc.) are utilized. Bumps, wires, conductive pastes, and / or other electrical connection mechanisms may be used to establish the electrical contact between the semiconductor device and the substrate, die, or lead frame of a package. In some embodiments, a metallic pad, or an under-bump metallization (UBM), may be located between the bmp and the bond pad where the UBM may contain an adhesion layer, a barrier layer, and a wetting layer. The final packaging process integrates such semiconductor chips / dies onto substrates using, for an example, interposers.

[0059] The device structure disclosed herein may be formed on at least a portion of a surface of the substrate of the device structure by providing the substrate, exposing the substrate to a polymerization initiator to obtain polymerization initiator sites on the substrate, and exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand, an activator, and optionally a solvent.

[0060] The components of the reaction composition, that is the monomer, the catalyst, the ligand, the activator, and the solvent (if present), may be combined in any order. E.g., the catalyst and the ligand may be provided in a solvent and may be mixed with the activator dissolved in a solvent prior to the addition of the monomer. E.g., the monomer, the catalyst and the ligand may be provided in a solvent and may be mixed with the activator dissolved in a solvent. E.g., the catalyst, the ligand, the catalyst may be dissolved in the monomer (acting as solvent), if the monomer is in liquid form.

[0061] Some methods for preparing a substrate for surface polymer formation, i.e. attaching polymerization initiators, have been described in the art. A brief description of processes that may be used in connection with the present disclosure is given below. However, it is to be understood that alternative processes may also be suited and workable within the context of the present disclosure.

[0062] Attachment of polymerization initiators to a surface of a substrate may as mentioned be performed by various procedures. The polymerization initiators may be provided with a predefined surface chemistry’ to enable attachment onto the surface or a portion of the surface of the substrate, depending on the nature of the substrate. Non-limiting examples of suitable chemistries for attaching polymerization initiators on surfaces include but are not limited to aryl diazonium salts, organosilanes, organothiols, organophosphonic acids, organophosphonates, catechols, iodonium salts, alkenes, alkynes, and sol-gel coatings. Surface anchored polymerization initiators can be prepared as multilayer films or monolayer films. Monolayer films can be densely packed (full monolayer coverage) or partly packed, covering all or only a part of the available surface. The density’ of the polymerization initiator influences the density’ of the subsequently formed surface polymer. Density of initiators would be understood by persons of ordinary skill as the number of polymerization initiators per unit area of the substrate.

[0063] The attachment of polymerization initiators usually follows a 1-step or a 2-step process. The 1- step process applies grafting of benzyl halide (like benzyl chloride) or secondary’ or tertiary halide moieties onto the surface of the substrate either by diazonium or silane grafting. The benzyl halide and secondary and tertiary halide moiety act as the polymerization initiator for the following surface-initiated polymerization. The 2-step process usually applies surface grafting of an initial organic compound with a nucleophilic group, and in a second step using the nucleophilic group to attach an initiator moiety. The nucleophilic group may include a hydroxyl or amine group. Then, the nucleophilic group may be reacted with an electrophile to add an initiator moiety, forming a covalent bond between the two. The initiator moiety may be, e.g., benzy l halide and tertiary halide moieties.

[0064] The polymerization initiator attachment process is further described below. The procedures mayin general apply to all types of substrates.

[0065] Silane grafting 1-step:

[0066] Initiators can be attached to a surface in one step by silane grafting of trialkoxy silane with benzyl halide or tertiary halide groups. The silane grafting is normally done either by vapor deposition, in solution, by spray coating, or paint-on coating.

[0067] Diazonium grafting 1-step:

[0068] Initiators can be attached to a surface in one step by grafting aryl diazonium salts with benzyl halide groups. The diazonium grafting is normally done either by activating the aryl diazonium salt electrochemically or chemically or by letting it react spontaneously. 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.

[0069] Diazonium grafting 2-step:

[0070] Another route of initiator attachment 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. Silane grafting 2-step:

[0071] 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.

[0072] Other processes for attaching first polymerization initiators may be applied. E.g., the polymerization initiator CPTMS ( / ?-chloromethyl)phenylethyl Jtrimethoxysilane) may be attached using a vapor deposition method or a dipping method. E.g., the polymerization initiator BiBB (bromoisobutyl bromide) may be attached by a dipping method. A polymerization initiator may also be formed by incorporation or attachment of a chloromethyl moiety, a sulfonyl chloride moiety, or benzylchloride moiety.

[0073] The surface polymer formed on a surface or a portion of a substrate may be composed of several types of monomeric units.

[0074] The surface polymers formed on a surface or a portion of a may be composed of more than two polymer molecules, wherein one of the polymer molecules are polymerized from polymerization initiators on the substrate, and wherein the other of the polymer molecules are polymerized from polymerization initiators on the already formed polymer molecules. By forming a first surface polymer from first polymerization initiator sites on the substrate, exposing said first surface polymer to a second polymerization initiator binding to groups on the first surface polymer, and exposing said first surface polymer to a second monomer to form polymer molecules from the second polymerization initiators, surface polymers with complex architecture may be obtained. The surface polymer may be exposed to third, fourth, fifth, sixth, etc. polymerization initiators binding the groups at least on the second, third, fourth, fifth, etc. polymer molecules. Each of the first, second, third, fourth, fifth, sixth, etc. surface molecules may be copolymers. Such structures make possible the preparation of surface polymers with a high average dry film thickness, such as above 0.5 nm, above 1 pm and above several pm.

[0075] Suitable examples of monomers for surface polymerization and polymer deposition are indicated below.

[0076] Thus, non-limiting examples of appropriate monomer types include anionic, cationic, zwitterionic, protic and aprotic monomers, and include acrylates, methacrylates, halogen- substituted alkenes, acrylamides, methacrylamides, and styrenes, as well as mixtures thereof. The generic monomer structure comprises a polymerizable part (a vinyl group), which in certain embodiments is connected to a functional group responsible for the specific functionality (e.g., adhesion, permeability, electric and ionic conductivities) of the certain monomer through a certain linker chemistry.

[0077] For acrylate monomers, non-limiting examples of functional moieties include but are not limited to alkyl groups, aryl groups, sulfonates, fluorosulfonates, carboxyls, metal carboxylates, ethers, poly(ether) groups, bis(sulfonyl)amides. fluorinated sulfonates, perfluoroalkyl carboxylate, borate, fluorinated borate, borate ester derivatives, bis(trifluoromethane)sulfonimide, triflimides and derivatives thereof, halogenated alkyl chains, and mono-, di-, and tri-alkoxy silanes.

[0078] The polymerizable part and the functional part of monomer can. in certain embodiments, be connected by a linker moiety. Non-limiting examples of appropriate linker chemistries include but are not limited to alkyl chain, esters, ethers, poly(ethers), amines, amides, ary ls, and any combination(s) thereof. Non-limiting examples of appropriate acry late monomers containing alkyl linkers include but are not limited to methyl acrylate, ethyl acry late, and lauryl acrylate. Non-limiting examples of monomers using ether and poly(ether) linker chemistry include but are not limited to poly(ethylene glycol) methyl ether acrylate, and poly(ethylene glycol) acrylate. Non-limiting examples of monomers without linker chemistry include but are not limited to acry lic acid, lithium acrylate, sodium acrylate, and vinyl imidazole.

[0079] For methacry late monomers, non-limiting examples of appropriate functional moieties include but are not limited to carboxylic acids, metal carboxylates, esters, alkyl alcohols, oxiranes (epoxides), linear and branched alkyl groups, alkenes, ary l groups, sulfonates, fluorosulfonates, bis(sulfonyl)amides, fluorinated sulfonates, perfluoroalkyl carboxylate, borate, fluorinated borate, borate ester derivatives, bis(trifluoromethane)sulfonimide, triflrmides, and derivatives thereof, halogenated alkyl chains, and mono, di, and tri-alkoxy silanes.

[0080] Non-limiting examples of linker chemistries include but are not limited to alkyl chains, esters, ethers, poly(ethers. amines, amides, aryls, and any combination(s) thereof.

[0081] Non-limiting examples of methacrylate monomers include but are not limited to methacry lic acid, lithium methacrylate, sodium methacry late, methyl methacrylate (MMA, potassium 3-sulfpropyl methacrylate (K-SPMA, 2-hydroxyethylmethacrylate (HEMA, glycidyl methacrylate (GMA, ethyl methacrylate. / ?-butyl methacrylate (BuMA, tert-butyl methacrylate (tBMA, lauryl methacry late, (((perfluorobutyl)sulfonyl)oxy)methyl methacrylate, 3-(N-((trifluoromethyl)sulf- onyl)sulfamoyl)propyl methacrylate, I A. I A.2A.2A-hepladecafluorodecyl methacry late (HFDMA, allyl methacrylate, 2-((tri ethoxy silyl)oxy)ethyl methacrylate, and 2-(3-(triethoxy- silyl)propyl)ethyl methacrylate.

[0082] Non-limiting examples of acrylate monomers include but are not limited to methyl acrylate (MA), tert-butyl acrylate (tBA). lauryl acrylate (LA), and 2-hydroxyethylacrylate (HEA).

[0083] Non-limiting examples of appropriate halogen-substituted alkene monomers include but are not limited to vinyl chloride, vinylidene difluoride, tetrafluoroethylene, chlorotrifluoroethylene, and hexafluoropropylene.

[0084] Non-limiting examples of appropriate acrylamide monomers include but are not limited to acry lamide, A-Ao-propylacrylamide. A-tert-butylacrylamide, and A-hydroxyethyl acrylamide.

[0085] Non-limiting examples of appropriate methacrylamide monomers include but are not limited to A-Ao-propylmethacrylamide, methacrylamide, A-tert-butylmethacrylamide, and A-hydroxyethyl methacrylamide.

[0086] Non-limiting examples of appropriate styrene monomers include but are not limited to styrene, 4- methylstyrene, 2,3,4,5,6-pentafluorostyrene, / ?-di vinyl benzene. 4-chlorostyrene, sodium 4- vinylbenzenesulfonate, lithium 4-vinylbenzenesulfonate, and 4-vinylphenyl 1, 1,2, 2, 3, 3, 4,4,4- nonafluorobutane- 1 -sulfonate.

[0087] Monomer(s) may be chosen to provide compatibility / adhesion / elastrcity, as appropriate for a specific application. Monomer(s) can also be selected to enhance or diminish electrical and / or ionic conductivity7, and / or permeability7. Monomers may be chosen to improve interface stability7of a surface in question. Monomers may suitably be used in an amount corresponding to a percentage of the total volume of the reaction medium. For example, a liquid monomer may constitute, e g., 0.5 vol%, 2 vol%, or 10 vol% of a reaction composition. For example, a solid monomer may constitute, e.g., 0.5 \\1%. 2 \vt%. or 10 wt% of the reaction composition. In each application, an amount of monomer may be chosen to provide a desired polymer formation kinetics, solubility of the monomer, and cost of the monomer.

[0088] In each application, the amount of monomer may be chosen to obtain desired polymerization kinetics and polymerization rate, solubility’ of the monomer, and cost of the monomer. The range for the amount of monomer may in most cases be 0.5 vol% to 50 vol%.

[0089] Following formation of the polymer molecule, 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, the polymer molecule is denoted PMMA. Likewise, 2-hydroxyethyl methacrylate is denoted HEMA, and after polymerization, the polymer molecule is denoted PHEMA. Thus, and by way of example, the surface polymer film may be composed of, e.g., PMMA or PHEMA.

[0090] Surface polymers comprising copolymers are also within the scope of the present disclosure.

[0091] Within the present context, the expression “‘copolymer’ or “copolymers” is intended to mean a surface polymer as defined herein comprising at least two different monomeric repeat units. Copolymers may be formed by copolymerizing different types of monomers or by subsequent partial chemical modification of a homopolymer (within the surface polymer) to add a chemical modification of one type of monomeric repeat unit to obtain a different type of monomeric repeat unit.

[0092] Several procedures are available for forming surface polymers on at least a portion of the surface of the substrate of the device structure. Procedures include (ARGET) ATRP and SET-LRP. 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, and a suitable equilibrium between activating and deactivating catalyst-ligand species is set to control surface polymer propagation. SARA-ATRP and SET-LRP are described, e.g., in https: / / www.cmu.edu / maty / atrp-how / procedures-for-initiation-of-ATRP / SARA-ATRP- or-SET-LRP.html. Both the SET-LRP and (ARGET) ATRP method CuCk or CuBn in the case of ARGET ATRP, and Cu(0) in the case of SET-LRP. The Cu-catalyzed 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 allows in general more control of the polymer propagation. Also included is Surface-Initiated Surface Polymer formation as described in WO 2024 155981 and WO 2019 196999, respectively. WO 2019 196999 describes the use of a catalyst based on, e.g., a Cu oxide, the Cu oxide forming a dormant (catalytically inactive) complex with the ligand (Cu(II) / L) which may be activated on demand to Cu(I) / L by an oxygen scavenger as catalyst activator. The dormant catalytic system described in WO 2019 196999 is halogen free at least to the extent that no halogen source is used to prepare the dormant (catalytically inactive) catalyst / ligand complex in contrast to SET-LRP and ARGET ATRP that make use of copper (Cu) chlorides or copper (Cu) bromides.

[0093] Catalysts to be used herein for forming surface polymers may. e.g., be based on and selected from copper (Cu), iron (Fe), and ruthenium (Ru), platinum (Pt). In particular, the catalyst may be obtained from Cu, Fe or Ru. Specific examples of such catalysts include CmO, CuO, CuCl, CuCh, CuBr, CuBr2, FeCh, FeBn, Fe2(SO4)s, FeCh, FeBn, FeSC , RuCh and RuCh hydrate as well as combinations thereof. The catalyst concentration in the reaction composition is typically in the range 0.001-1 mM. The concentration of catalyst in the reaction composition may be in the range 0.02-0.32 mM, for example 0.02 mM, 0.04 mM, 0.08 mM, 0.16 mM, or 0.32 mM. The activator for the catalyst (e.g., an oxygen scavenger) may be used in excess compared to the catalyst. Excess catalyst activator may, e.g., be 10-500 times. The catalyst activator is responsible for the turnover between oxidized deactivating and / or activating catalyst states. It is presently believed that the principal reaction pathway for catalyst activation is reduction, that is, the catalyst activator is a species which is capable of reducing the catalyst of the complex between the catalyst and the ligand from its inactive state to its catalytically active state, where surface polymer formation can take place. Examples of suited catalyst activators are sodium ascorbate, ascorbic acid, hydrazine, hydrazine hydrate, sodium hypophosphite, glucose, glucose with oxidizing enzyme (GOx), tin 2- ethylhexanoate, sodium phenoxide, sodium dithionite, and a mixture of iron powder and sodium chloride.

[0094] Ligands to be used herein include, but are not limited to, nitrogen-containing ligands. Nonlimiting examples of such nitrogen-containing compounds are bi-, tri-, or tetradentate amine ligands (containing two, three or four amine substituents) which are aliphatic and / or aromatic in nature. In particular, such ligands include N,N,N N”, A'"'-pentamethyldiethylene-triamine (PMDETA), tris[2-(dimethylamino)ethyl]amine (Me TREN). tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TPMA), EIMTETA ( I . I .4.7. I O. l ()-hexamethyltriethylenetetramine). TMEDA (tetramethylethylenediamine), Me-iCyclam (1,4, 8,1 l-tetramethyl-1,4,8,11-tetraaza- cyclotetradecane), and 2.2’-bipyridyl (BiPy), and combinations thereof. The amount of ligand in the reaction composition is defined as a ratio to the concentration of catalyst in the reaction composition. The ratio of ligand to catalyst in the reaction composition is in the range 0.001: 1 - 1000:1. The ratio of ligand to catalyst in the reaction composition may be in the range 0.005: 1 - 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, excess amount ligand as compared to amount catalyst may be used.

[0095] The catalyst and the ligand form a complex. One, two, three or even four ligands may form complexes with one catalyst.

[0096] The reaction composition may comprise a solvent. Suitable solvents include but are not limited to alcohols, dipolar aprotic solvents (for examples, tetrahydrofuran, methyl acetate, ethyl acetate, buty l 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. E.g.. the solvent may be a mixture of one or more miscible solvents. E g., the solvent may be an aqueous solvent, such as a mixture of water and one or more alcohols. Alcohols include, but are not limited to, methanol, ethanol, and isopropanol.

[0097] The reaction composition may further comprise a buffer. Buffers usually are aqueous. Suitable buffers include carbonate buffers, glycine buffers, citrate buffers, phosphate buffers, acetate buffers, ammonium buffers (ammonium chloride / ammonia), formate buffers, sodium ascorbate / ascorbic acid buffers, and / or zwitterionic buffers such as Good’s buffers. Good’s buffer include MES, PIPES, MOPS, HEPES, CHES, CAPSO and / or CAPS. The buffer may provide stabilization of the reaction composition during the surface polymer formation.

[0098] The reaction composition may further comprise an additive in the form of a surfactant and / or a polyquatemium compound. Suitable surfactants include sodium dodecyl sulfate (SDS). Triton- X100, dioctyl sodium sulfosuccinate (DOSS), cetrimonium bromide (CTAB). cetrimonium chloride (CT AC), and / or dimethyldioctadecylammonium chloride. Suitable polyquatemium compounds include polyquatemium-7, polyquatemium-10, polyquatemium-11, polyquatemium- 14, polyquatemium-D16, polyquatemium-31, polyquatemium-36, polyquatemium-46, polyquatemium-65, polyquatemium-68, polyquatemium-79.

[0099] The reaction composition may further comprise a halide compound for increasing the “livingness” of the surface polymerization of monomers. A “living7’ 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 show7a linear relationship between polymer chain length and time. The halide compound to be used herein is a compound capable of providing a halide anion. Non-limiting examples of such compounds are NaCl, NaBr, KC1, KBr, MgCh, MgBr2, CaCl2, HC1, HBr, Lid, LiBr, CaBr2, 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-capping, and thus deactivating, propagating surface polymer chain-end radicals to deliver alkyl halides. Consequently, the number of propagating surface polymer chainend 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. In an embodiment, the catalyst is Cu, the ligand is MesTREN, PMDETA, TREN, HMTETA, TMEDA, or Me4Cyclam and the halide compound is NaCl.

[0100] The reaction composition for surface polymer formation may further be pH controlled. That is, an acidic or alkaline substance may be added one or more times to the reaction composition prior to or during surface polymer formation. The pH of the reaction composition may depend on acid dissociation constant of the complex formed between the catalyst and the ligand complexes. pH control is described further in WO 2024 155981, which is incorporated herein by reference. To meaningfully determine pH and / or pKa. the reaction composition may in general be aqueous, i.e., meaning that water is present in a certain amount. Since the catalyst / ligand complexes mentioned herein are alkaline, the term pKaH is used, which refers to the pKa of the conjugate acid. The higher the pKaH value, the stronger the base. For species which may be protonated more than once pKaHi refers to the pKa of the conjugate acid obtained after the “first” protonation, and pKaH2refers to the pKa of the conjugate acid obtained after the “second” protonation; pKaHi is in this case always higher than pKJ-b, i.e., pK.iHi > pKJHb. Specific pK.i and pIGH values may be calculated using known titration methods, or, where available, be looked up in various publications and handbooks. Non-limiting examples of alkaline substances are potassium hydroxide (KOH), lithium hydroxide (LiOH), tripotassium phosphate (K3PO4), sodium carbonate (Na2COs), or sodium ethoxide (CH3CH2ONa). Non-limiting examples of acidic substances are methanesulfonic acid (MSA), hydrochloric acid (HC1), sulfuric acid (H2SO4), phosphoric acid (H3PO4), 2,2,2-trifluoroacetic acid (TFA),p-toluenesulfonic acid (pTSA), and nitric acid (HNO3).

[0101] The formed surface polymer may be cross-linked. “Chains” of surface polymers on the surface of the substrate may be cross-linked via several pathways, depending on their structure and chemical functionalities. Generally, a cross-linking molecule must be able to either react at least with two reactive groups present in the polymer molecules, or, be able to react at least once with reactive groups present in the surface polymer and generate in this reaction at least one new reactive group, which may react further with neighboring chains of the surface polymer, leading to cross-linking. As an example of the latter, poly(glycidyl methacrylate) (PGMA) contains a reactive oxirane(epoxide)-moiety, which upon reaction with a nucleophile (Nu) yields a hydroxyl group, and a carbon-Nu covalent bond. The formed hydroxyl group may itself be considered a nucleophile and can react with another oxirane moiety of a neighboring polymer molecule, resulting in formation of a carbon-0 covalent bond, w hich is responsible for the cross-linking of two chains of surface polymers. Suitable nucleophiles for reaction with PGMA include but are not limited to amines, thiols, hydroxyls. Examples of nucleophiles which may react only once with PGMA surface polymer chains include alcohols such as ethanol and phenol, secondary amines such as diethylamine, and thiols such as 1 -decanethiol. Examples of nucleophiles that may react at least twice with PGMA surface polymer chains include primary amines such as allyl amine and propyl amine, diamines such as 1 ,2-diaminoethane, diols such as ethylene glycol and bisphenol A, and dithiols such as ethylene bis(thioglycolate). Cross-linkers which may react e.g. at least three times can be conceptualized by e.g. branched triamines such as propane- 1, 2, 3-amine, and glycerol. In order for a molecule to cross-link chains of surface molecules that contain nucleophilic functional groups such as hydroxyls and amines, the cross-linker molecule should comprise at least two reactive electrophilic sites. Examples thereof include di-acid halides such as succinyl chloride, adipoyl chloride, fumaryl chloride and azealoyl chloride, or dicarboxylic acids such as maleic acid, glutaric acid, and terephthalic acid, winch may be activated by suitable reagents such as carbodiimides like l-ethyl-3-(3-dimethylaminopropyl)carbodiimide, diisopropylcarbodiimide, or N,N’ -di cyclohexylcarbodiimide, or acid halide forming species such as thionyl chloride.

[0102] A reaction composition as defined above may be applied for forming the surface polymer. As mentioned above, the reaction composition may comprise a monomer, a catalyst, a ligand, an activator, and a solvent. The catalyst may be selected from the catalysts defined above. In particular, the catalyst may be obtained from Cu, Fe, or Ru. The reaction composition to be applied in the method may comprise a ligand as defined above. In particular, the ligand may be selected from A,A,A’.A'’.A '’-pentamethyldiethylene-triamine (PMDETA). tris[2-(dimethyl- amino)ethyl] amine (MeeTREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TPMA), 1,1, 4, 7, 10,10-hexamethyltri ethylenetetramine (HMTETA), tetramethylethylenediamine (TMED A), 1 ,4, 8, 11 -tetramethyl- 1 ,4, 8, 11 -tetraazacy clotetradecane (Me4Cy- clam), and / or 2.2' -bi py ri dy 1 (BiPy). The reaction composition may comprise PMDETA as ligand. The reaction composition may comprise TPMA as ligand.

[0103] The reaction composition to be used in the method may comprise an activator. Suitable activators may be oxygen scavengers as defined above. In particular, the activator may be selected from sodium ascorbate (NaAsc), ascorbic acid (Asc), hydrazine hydrate, sodium thiosulfate, sodium sulfite, sodium dithionite, glucose, glucose with glycose oxidizing enzyme (GOx), and / or pyrogallic acid. The reaction composition to be used in the method may further comprise a buffer. Suitable buffers are defined above. The reaction composition to be used in the method may further comprise a halogen salt (metal halide). Suitable halogen salts are defined above. The reaction composition to be used in the method may comprise a surfactant. Suitable surfactants are defined above.

[0104] The reaction composition may suitably comprise at least one solvent as defined above. The solvent may be any solvent that provides sufficient solubility of the components of the reaction composition. Suitable solvents include, but are not limited to, alcohols (for example, methanol, ethanol, and isopropanol), dipolar aprotic solvents (for example, tetrahydrofuran (THF), methyl acetate, ethyl acetate, butyl acetate, dimethyl sulfoxide (DMSO), dimethyl formamide (DMF)), methylene carbonate, ethylene carbonate, propylene carbonate, ethyl lactate alcohol, toluene ionic liquids, supercritical CO2, and water, as well as mixtures thereof. For forming surface polymers, the substrate and the reaction composition as defined herein are typically kept in contact with each other for a suitable period (residence time), such as from 30 seconds to 5 hours. The residence time includes, but is not limited to 30 seconds, 1 minute, 5 minutes, 30 minutes, 1 hour, 2 hours. 3 hours, 4 hours and 5 hours. The surface polymer formation may take place at ambient temperature (room temperature), or with cooling or heating. Suitable temperatures are such from 20°C up to 120 °C, such as from room temperature (approximately 20°C) to 120°C. Specific temperatures include, but are not limited to, 20°C, room / ambient temperature (approximately 20°C), 30°C. 50°C, 60°C. 70°C, 80°C. 90°C, 100°C, 110°C, and 120°C. The residence time and temperature during the residence time may suitably be computer controlled. Following formation of surface polymers, the substrate may be subjected to a rinsing and cleaning process, typically flushing with a suitable solvent, sonicating, and / or drying. The substrate onto which surface polymers are to be formed may be brought into contact with the reaction composition by immersing the substrate into the reaction composition, or by spraying or painting the reaction composition onto the substrate. Polymerization times may depend on the kinetics of the polymerization, the monomer used, the catalyst / ligand complex used and further on the type of substrate. Other ways of adjusting residence time and temperature may be based on conditions in the compartment holding the reaction composition (bath conditions) and / or measurements.

[0105] It is to be understood that the components of the reaction composition, which are needed for forming surface polymers, may be provided as discrete components to be mixed before surface polymerization, or may be pre-mixed and activated for surface polymerization shortly before the surface polymerization, that is, the monomer, the solvent, the catalyst / ligand complex are premixed and the catalyst activator is added shortly, usually within 5 minutes, before surface polymerization.

[0106] The substrate may be rinsed one or more times following surface polymer formation. Suitable rinsing may include flushing the substrate with different solvents (such as acetone, water, ethanol or combinations thereof), optionally in combination with sonication.

[0107] It is to be understood that the procedures may be repeated to form a surface polymer film composed of at least two polymer molecules, wherein one polymer molecule is polymerized from surface-bound polymerization initiators, and wherein the second polymer molecule is polymerized from polymer molecule-bound polymerization initiators. 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 (ambient temperature, ambient pressure) 1-30 minutes. In some cases, the substrates may be flushed with acetone after withdrawal from the reaction composition, followed by air-drying 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. Alternative, the substrate(s) may be flushed with iPrOH, then sonicated in iPrOH for 5 minutes and left to dry under nitrogen flow for 10-30 minutes.

[0108] Within the scope of the present disclosure, the surface polymer film may possess specific properties obtained through copolymers as described above. The individual components (different monomers) of the copolymers may contribute different properties resulting in a surface polymer with a combination of desired properties. Surface polymer film can be applied or formed by repeating the polymerization procedures described above to build up copolymers. The same or different monomers can be applied relative to the monomers used to form previous layers. Forming additional surface polymers may be repeated multiple times to obtain a more complex or thicker surface polymer. Surface polymers can also be formed using two or more different monomers grown from one type or different types of initiators thereby forming random or mixed surface polymers, respectively. Hence, 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.

[0109] The surface polymer may be a polymer brush. Polymer brushes are upright polymers formed through propagating monomeric units extending the polymer chain from the polymerization initiators on the surface of the substrate.

[0110] Surface polymer films as described herein may have a thickness (as measured by ellipsometry) of from a few nanometers and up to several pm. The thickness of the surface polymer may depend on the coefficient of thermal expansion (CTE) of the substrate and the metal deposited, AT as well as other parameters. Non-limiting lower range may be from 5 nm, 10 nm or 20 nm depending on application. Non-limiting higher ranges may be from 500 nm and up to 8 pm. For example, 1 pm, 2 pm, 3 pm, 4 pm. 5 pm, 6 pm, or 7 pm. In some cases where the substrate is a hollow structure (for example a through glass via (TGV)), the thickness of the surface polymer film may be up to up to 10% of the radius of the hollow structure, or up to 5% of the radius of the hollow structure. The lower limit of surface polymer film thickness in case of a hollow structure (for example a through glass via (TGV)) may be 0.1% of the radius of the hollow structure.

[0111] As used herein, the terms “a substrate” and “the substrate” are intended to include both a single substrate and a plurality7of substrates in any form and shape.

[0112] As mentioned above, the surface polymers may suitably be formed on at least a portion of the surface of the substrate of the device structure, or may be formed on all surfaces available on the substrate of the device structure, that is, surface(s) or portions of surfaces with polymerization initiators attached. Surface polymers may be formed on available surfaces at the same time (e g., in the case of single-piece substrates) or on available surfaces in a sequential manner (e.g., in the case of fibers, threads, wires etc.).

[0113] Surface polymers formed on at least a portion of the surface of the substrate may be poly(2- hydroxyethyl methacrylate) (PHEMA), poly(glycidyl methacrylate) (PGMA), poly(n-butyl methacrylate) (PBuMA), poly(tert-butyl methacrylate) (PtBMA), poly(benzyl methacrylate) (PBnzMA), poly(2-ethylhexyl methacrylate) (PEHMA), poly(2-hydroxyethyl acry late) (PHEA), and polysty rene (PSt), or a combination (copolymer) thereof.

[0114] The present disclosure provides methods for preparing device structures as disclosed herein, the method comprising providing a substrate having a surface polymer film comprising polymer molecules on at least a portion of the surface, and exposing the substrate to at least one solution of a first metal to deposit the first metal on and within the surface polymer film. The concept is illustrated schematically in Fig. 4, showing the at least one first metal 460 being deposited within the surface polymer film 350. The at least one first metal may to some extent be deposited on the surface polymer film 350 (not illustrated in Fig. 4). The at least one first metal may be selected from metals able to coordinate with functional groups on the polymer molecules of the surface polymer. Thus, the at least one first metal may be a combination of two or more metals or compounds. The at least one first metal may be a transition metal as defined in the Periodic Table of Elements. Non-limiting examples include palladium (Pd), tantalum (Ta), ruthenium (Ru), and cobalt (Co). The at least one first metal may further be selected from metal-containing compounds that may be layered, and, in some applications the at least one first metal may function as diffusion barriers or as electrical conductors. Nonlimiting examples include TaN and RuOx.

[0115] The method for preparing the device structure as disclosed herein may further comprise exposing the substrate to a solution of a second metal to deposit the second metal on and within the surface polymer film. The method may further comprise depositing, by an electroless deposition process, a metal layer comprising the second metal, wherein the first metal catalyzes the electroless deposition of the second metal. The first metal catalyzes the deposition of the second metal upon activation of the first metal. The method may further comprise annealing the device structure.

[0116] In an aspect of the present disclosure, a method is provided, the method for preparing a device structure as defined herein comprising providing a substrate having a surface polymer film comprising polymer molecules on at least a surface of the substrate, exposing the substrate to at least one solution of a first metal to deposit the first metal on and within the surface polymer film, exposing the substrate to a solution of a second metal to deposit the second metal on and within the surface polymer film, and depositing, by an electroless deposition process, a metal layer comprising the second metal, wherein the first metal catalyzes the electroless deposition of the second metal. In the method, the first metal catalyzes the depositing of the second metal upon activation. The method may further comprise thermally annealing the device structure.

[0117] By the present disclosure, a device structure may be provided, the device structure having a first metal and a second metal deposited on and within a surface polymer film. By the present disclosure, a device structure may be provided, the device structure having first metals being a metal and a metal-containing compound, and a second metal. By the present disclosure, a device structure may be provided, the device structures having first metals being a metal, a further metal, and a metal-containing metal, and a second metal. The first metal may be palladium (Pd). The first metal may be palladium (Pd), and tantalum (Ta), ruthenium (Ru), cobalt (Co), TaN, or RuOx, a combination thereof. The second metal may be copper (Cu).

[0118] The device structure may comprise at least one first metal and a second metal, deposited on and within the surface polymer film, the depositing of the at least one first metal and the second metal on and within the surface polymer film being obtained by methods other than electroless deposition, like physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), etc. The at least one first metal may be a first metal being an adhesion promoting metal, and the other at least one first metal may be a diffusion barrier functioning metal or metal-containing compound.

[0119] It is to be understood that the at least one first metal and the second metal are provided as ions to deposit the metals. E.g., Pd may be provided as a salt, e.g. as Na2PdC14, optionally in combination with other chemical agents. In a reduction step ions of the first metal are converted to the metal, by way of example, Pd ions to Pd(0), e.g., by bringing the substrate in contact with Na2PdC14, and NaBEU. among other chemical reagents. In an acceleration step the seeds of the first metal is activated for binding to the second metal, by way of example, the Pd(0) seeds deposited within and on the surface polymer film are activated for Cu-binding during the electroless process, and the accelerator step may comprises applying a solution of formaldehyde binding to the Pd(0) as well as other chemical agents like pH adjusting agents, stabilizers, and additives. Cu as second metal is deposited by an electroless process and is catalyzed by the presence of the Pd(0) seeds within and on the surface polymer film. In the electroless process, Cu ions are, e.g., obtained from Cu salts like CuSC . Other components may be potassium sodium tartratrate, and EDTA disodium salt. The principles of the electroless process are well described in the art. The electroless step may be used to plate other metals such as nickel (Ni), nickel-phosphorus (Ni-P), nickel-phosphorus-diamond (Ni-P-D) composite, nickel gold (Ni- Au), nickel-boron (Ni-B), palladium (Pd), palladium-nickel (Pd-Ni), and silver (Ag). Depending on which metals are used for electroless deposition, the at least one first metal may be different.

[0120] Architecture of the device structure herein may be created by presenting a device structure having a surface polymer film and then depositing the first and second metals by non-electroless methods, for example well-known PVD, CVD, and ALD methods as referred to above. The said first metals may be Ti, Ta, Ru, Co, TaN, and combinations thereof. The said second metal may be Cu.

[0121] The methods for preparing a device structure as disclosed herein may comprise providing a substrate having a surface polymer film comprising polymer molecules on at least a surface of the substrate, exposing the substrate to at least one solution of a first metal to deposit the first metal on and within the surface polymer film, exposing the substrate to a solution of a second metal to deposit the second metal on and within the surface polymer film, depositing, by an electroless deposition process, a metal layer comprising the second metal, wherein the first metal catalyzes the electroless deposition of the second metal. In the method, the first metal catalyzes the depositing of the second metal upon activation of the at least one first metal. The method may further comprise thermally annealing the device structure.

[0122] In the methods above, the at least one solution may comprise the first metal as a salt, among other components. The solution of the first metal may be aqueous or non-aqueous. The first metal may be palladium (Pd). The salt of Pd may be Na2PdCk

[0123] In the methods above, the second metal may be provided in a solution comprising the second metal as a salt, among other components. The solution of the second metal may be aqueous or non-aqueous. The second metal may be copper (Cu). The salt of Cu may be CuSCh.

[0124] The methods described above may further comprise providing a substrate, exposing the substrate to polymerization initiators to obtain polymerization initiator sites on the substrate, and exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand, an activator, and optionally a solvent.

[0125] The reaction composition and its components may be as defined above. The general procedures of performing the method are as disclosed herein.

[0126] In aspects of the present disclosure, a system for forming a device structure as described herein is provided. The system comprises a number of containers holding chemistry needed to form the device structure. An automated system may further comprise one or more displacement devices, e.g., for transporting components of the device structure. The system may further comprise devices for, e.g., adding, withdrawing, and / or measuring certain parameters during the forming of the device structure. The system may further comprise devices for pre-treating, post-treating, and / or cleaning / rinsing during the forming of the device structure.

[0127] Thus, in an aspect, a system for forming a device structure is provided, the system comprising a first container containing a reaction composition for forming a surface polymer film from polymerization initiator sites on at least a portion of a surface of a substrate, at least one second container containing a solution of a first metal for depositing the first metal on and within the surface polymer film, at least one third container containing a solution for reducing the first metal deposited on and within the surface polymer film, at least one fourth container containing a solution for activating the first metal deposited on and within the surface polymer film, a fifth container containing an electroless solution of a second metal for depositing, by an electroless procedure, the second metal on and within the surface polymer film, and a substrate displacement device, wherein the substrate displacement device may bring at least a portion of the substrate with polymerization initiator sites into contact with the reaction composition in the first container for a first controlled time, wherein the first controlled time may be sufficient for forming the surface polymer film from the polymerization initiator sites, and wherein the substrate displacement device may bring at least a portion of the substrate with surface polymer film into contact with the solution in the at least one second container for a second controlled time, wherein the second controlled time may be sufficient for depositing the first metal on and w ithin the surface polymer film, wherein the substrate displacement device may bring at least a portion of the substrate with surface polymer film and first metal into contact with the solution in the at least one third container for a third controlled time, wherein the third controlled time may be sufficient for reducing the first metal in and within the surface polymer film, wherein the substrate displacement device may bring at least a portion of the substrate with surface polymer film and first metal into contact with the solution in the at least one fourth container for a fourth controlled time, wherein the fourth controlled time may be sufficient for activating the first metal deposited on and within the surface polymer film, and wherein the substrate displacement device may bring at least a portion of the substrate with surface polymer film and first metal into contact w ith the solution in the fifth container for a fifth controlled time, wherein the fifth controlled time may be sufficient for depositing, by an electroless deposition process, a second metal on and within the surface polymer film. The system may comprise one or more additional containers for rinsing the substrate. The system may further comprise a further container containing a polymerization initiator for forming polymerization initiator sites on at least a portion of a surface of the substrate. The system may comprise a further container containing a cross-linking agent for cross-linking the polymer molecules of the surface polymer film, wherein the substrate displacement device may bring at least a portion of the substrate with surface polymer film into contact with the crosslinking agent in the further container for a further controlled time, wherein the further controlled time may be sufficient to cross-link the polymer molecules in the surface polymer film. The crosslinking of the polymer molecules of the surface polymer film may take place before depositing of the first metal, or after depositing of the first metal. The system may comprise an oven for thermally annealing the device structure. For forming the device structure, the first metal may be palladium (Pd), and the second metal may be copper (Cu).

[0128] Fig. 9 shows a schematic representation of a system for forming device structures according to the above. In Fig. 9, substrates 910 are moved between containers 920, 930, 940, 950 by the aid of a displacement device (not shown). Containers 920, 930, 940, 950 may hold chemistries for attaching polymerization initiators, the reaction composition for forming the surface polymer film on the substrate, rinsing, cross-linking, deposit first and second metals, and annealing the device structure.

[0129] Aspects and embodiments of the disclosure are further illustrated by the following, non-limiting examples.

[0130] Examples

[0131] Chemicals

[0132] 4,?Silicon wafers substrates (Test CZ-Si. p-type (boron), thickness 525 ± 25 pm) purchased from MicroChemicals GmbH.

[0133] Glass substrates (Coming® Eagle XG Glass, 100 x 100 x 0.7 mm3) purchased from Edmund Optics BV.

[0134] ABC clean A200 purchased from ABC-Clean ApS.

[0135] Ammonia 25% p.a. purchased from Chemsolute.

[0136] Acetone (>99%) purchased from Chemsolute.

[0137] Ethanol (EtOH) (96%) purchased from Kiiltoclean.

[0138] Isopropyl alcohol / ispropanol (iPrOH) 99.8% purchased from ChemSolute.

[0139] Dichloromethane (DCM) (>99.8%) purchased from ChemSolute.

[0140] N,N-Dimethylformamide (DMF) (>99.9%) purchased from ChemSolute.

[0141] H2O2(30% in water) purchased from ChemSolute.

[0142] Acetonitrile (MeCN) (>99.9%) purchased from ChemSolute. Sulfuric acid (H2SO4) >95%) purchased from ChemSolute.

[0143] Sodium hydroxide (NaOH) >99%) purchased from ChemSolute.

[0144] Triethylamine (EtsN) (>99.0%) purchased from ChemSolute or TCI Europe N. V.

[0145] Tris(2-pyridylmethyla)amine (TPMA) (97%) purchased from BLD Pharma. tris [2-(dimethylamino)ethyl] amine (MesTREN, >98% grade) purchased from abcr or Alfa Aesar.

[0146] 4-(Dimethylamino)pyridine (DMAP) (>99%) purchased from TCI Europe N. V.

[0147] Allylamine (98%) ought from abcr

[0148] Glycidyl methacrylate (GMA) monomer (>97%) purchased from Sigma Aldrich.

[0149] 2 -Hydroxy ethyl methacrylate (HEMA) (97%) purchased from Sigma Aldrich.

[0150] 2-Hydroxyethyl acrylate (HEA) (>95.5%) purchased from Sigma Aldrich.

[0151] Styrene (St) (>99%) purchased from Sigma Aldrich.

[0152] Ethylene glycol dimethacrylate (EGDMA) (>98%) purchased from Sigma Aldrich.

[0153] Adipoyl chloride (ADC) (97% Purity) purchased from abcr.

[0154] Alpha-bromoisobutyryl bromide (BiBB) (98%) purchased from Sigma Aldrich.

[0155] 4-(Chloromethyl)phenyltrimethoxysilane (CPTMS) (95%) purchased from Gelest.

[0156] Sodium ascorbate (NaAsc) (>98%) purchased from Sigma-Aldrich.

[0157] Copper(ll)chlonde dihydrate (CuCb 2H2O) (>99.0%), purchased from Sigma Aldrich.

[0158] NaHCCh (>99.7%) bought from ChemSolute.

[0159] Na2COs (>99.8%) bought from ChemSolute.

[0160] Aqueous NaOH (1.5 mL, 50% w / w from ACME analytical).

[0161] ALCUP MAT-433-SP (Uyemura, Product Code 9100468).

[0162] Uyemura ALCUP MAB-435-D (Uyemura, Product Code 9100471).

[0163] Uyemura ALCUP MAB-435-C (Uyemura, Product Code 9100470).

[0164] Uyemura ALCUP MAB-435-AX (Uyemura, product Code 9100903).

[0165] Uyemura ALCUP MEL-437-M (Uyemura, Product Code 9100472).

[0166] Uyemura THRU-CUP PEA-531-A (Uyemura, product Code 9100473).

[0167] Uyemura THRU-CUP PEA-531-B (Uyemura, Product Code 9100474).

[0168] Uyemura THRU-CUP PEA-531-C (Uyemura, Product Code 9100475).

[0169] Uyemura THRU-CUP PEA-531-D (Uyemura. Product Code 9100476).

[0170] Uyemura THRU-CUP PEA-531-E (Uyemura. Product Code 9100477).

[0171] Double-sided tape (Tesa 4965).

[0172] VHB tape (3M).

[0173] GT tape (3M). 111 adhesion promoter (3M).

[0174] Scotch Brite abrasive pad (3M).

[0175] EP 907 Epoxy (Permalock).

[0176] Equipment

[0177] 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 Dl-water had a conductivity of <0.5 pS, indicating an ultrapure quality with very low presence of ions below 0. 1 mg / L. The quality of the Dl-water was confirmed at least weekly. •‘Big sonicator” refers to an ULTRASONIC CLEANER PROCLEAN 28.0 from Ulsonix (40 kHz, 480 W).

[0178] “Sonicator” refers toto a Bandelin Sonorex Super RK100 sonicator (35 kHz ultrasound frequency, 80 W nominal ultrasonic power).

[0179] ■‘Vacuum oven’’ refers to a Faithful Vacuum Drying Oven-DZ-BCII.

[0180] “Oven” or “conventional oven” refers to a Binder model FD 56.

[0181] Annealing of electroless deposited copper was carried out in a Yield Engineering Systems PB- 450 vacuum cure system.

[0182] Ellipsometry was measured on a J. A. Woollam M-2000 Ellipsometer. This instrument was set to measure 45 points on each substrate, unless otherwise indicated. Each point was analyzed using a Cauchy model providing 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.

[0183] Tape pull testing was carried out using a Mark-10 F305 Test Frame with a 90-degree peel test fixture.

[0184] Stud pull testing was carried out using a Positest AT-A instrument.

[0185] Example 1

[0186] SILICON SUBSTRATES: Pre-cleaning

[0187] Si Pre-cleaning procedure 1 :

[0188] Racks holding the Si substrates (quadrants cut from 4” Si wafers) were placed in a 3.75% aqueous solution of ammonia and sonicated for 10 minutes. Then, the substrates were flushed with deionized water and sonicated in deionized water for 10 minutes using a sonicator. Thereafter, the racks holding the substrates were transferred to a 5% solution of ABC clean A200 and sonicated for 10 minutes. This step was followed by flushing the substrates in deionized water and sonicating the substrates in deionized water for 5 minutes. Finally, the substrates were flushed with acetone and left to dry at room temperature (ambient pressure, ambient temperature).

[0189] Si Pre-cleaning procedure 2:

[0190] Silicon (Si) substrates were flushed with iPrOH to remove any dust / other residues and were left to dry at ambient conditions (ambient pressure, ambient temperature). The substrates were transferred to a stainless steel rack, and the substrates remained in the rack for the rest of the precleaning procedure. 150 mL of 25% ammonia solution was mixed with 850 mL Dl-water to obtain a 3.75 v / v% ammonia solution. The substrates were submerged in the ammonia solution and sonicated for 10 minutes, and then thoroughly rinsed with Dl-water, before being submerged in fresh Dl-water and sonicated for 10 minutes. 50 ml ABC-Clean 200 solution was mixed with 950 mL Dl-water corresponding to a 5 v / v% solution. The substrates were submerged in the ABC-Clean solution and sonicated for 10 minutes. The substrates were thoroughly rinsed with Dl-water and sonicated in fresh Dl-water for 5 minutes, followed by a thorough rinse with acetone and sonication for 5 minutes in acetone. The substrates were withdrawn and dried in an oven at 80°C for 15 minutes.

[0191] Si Pre-cleaning procedure 3:

[0192] Racks containing the substrates were placed in iPrOH and sonicated for 5 minutes in a big sonicator. Then, the substrates mounted in the pre-cleaning containers were placed in an oven at 80°C for 15 minutes. Thereafter, the racks containing the substrates were transferred to a 5: 1 : 1 DI- water / NH-iOH / FLCh solution at temperatures between 70°C and 75°C and sonicated for 10 minutes in a big sonicator. Next, the substrates were flushed under a running tap of Dl-water and transferred to a Dl-water container and sonicated for 5 minutes. Finally, the substrates were transferred to an iPrOH container and sonicated for 5 minutes, before being dried in an oven at 80°C for 15 minutes.

[0193] Si Pre-cleaning procedure 4:

[0194] In this procedure, the Si substrates were not cleaned prior to being subjected to the deposition of polymerization initiators. Example 2

[0195] GLASS SUBSTRATES: Pre-cleaning

[0196] Glass Pre-cleaning 1 :

[0197] Racks holding the glass substrates were flushed with iPrOH to remove any dust parti cles / other residues, and airdried at ambient conditions (ambient pressure, ambient temperature). The racks holding the substrates were placed in an aqueous NaOH solution at 60°C (400 g in 800 mL) for 10 minutes. Then, the substrates were flushed with Dl-water and sonicated in Dl-water for 5 minutes using a sonicator. Then, the substrates were flushed with iPrOH and sonicated in iPrOH for 5 minutes using a sonicator. Finally, the substrates were left to dry' in an oven at 80°C for 15 minutes.

[0198] Glass Pre-cleaning 2:

[0199] Glass substrates were flushed with iPrOH to remove any dust / other residues and left to air-dry at ambient conditions (ambient pressure, ambient temperature). The substrates were placed in a stainless steel rack. A glass container was filled with 1 L Dl-water and sonicated for 5 minutes. The substrates (in the rack) were dipped in and out of the Dl-water 5 times, and “rocked” back and forth under the Dl-water 5 times. The substrates were left in the Dl-water. In the meantime, 1 L of 5 M NaOH solution of Dl-water (200 g NaOH in 1 L Dl-water) was prepared and sonicated for 2 minutes, then poured into a glass container. The solution self-heated to approximately 60°C and was used while still hot. A sonicator was filled with warm tap water, and the 5 M NaOH solution was placed in the sonicator. The rack holding the substrates was dipped in and out of the NaOH solution 5 times, and “rocked’’ back and forth 5 times. Then, the substrates were sonicated for 1 minute and subsequently left for 9 minutes. The substrates in the rack were withdrawn from the 5 M NaOH solution and flushed with Dl-water and transferred to a container filled with pre-sonicated Dl-water. The substrate rack was dipped in and out of the Dl-water 5 times, and “rocked” back and forth 5 times and sonicated for 1. The pH value of the Dl-water was measured, and in the case the Dl-water was alkaline, the water flushing step w as repeated and the pre-sonicated Dl-water replaced until neutral pH was reached. Following the last Dl-water rinse, the substrate rack flushed with iPrOH. transferred to an iPrOH bath (presonicated for 5 minutes), dipped in and out of the iPrOH bath 5 times, and “rocked” back and forth 5 times, before being sonicated for 1 minute. The substrate rack was then withdrawn from the iPrOH bad and dried in an oven for 15 minutes. The oven was heated to 80°C. Glass Pre- 3:

[0200] Racks holding the glass substrates (roughly 50 x 50 mm2or roughly 33 x 100 mm2) were flushed with iPrOH to remove any dust parti cles / other residues, and airdried at ambient conditions (ambient pressure, ambient temperature). The racks holding the substrates were placed in an aqueous NaOH solution at 60°C (5 M) and sonicated for 10 minutes. Then, the substrates were flushed with Dl-water and sonicated in Dl-water for 5 minutes using a sonicator. Then, the substrates were flushed with iPrOH and sonicated in iPrOH for 5 minutes using a sonicator. Finally, the substrates were left to dry in an oven at 80°C for 15 minutes.

[0201] Example 3

[0202] Polymerization initiator

[0203] Polymerization initiator grafting (Procedure 1):

[0204] Substrates, pre-cleaned as described above, were used for surface initiator-modification with (p- chloromethyl)phenyltrimethoxysilane (CPTMS) polymerization initiators using a chemical vapor deposition method. The substrates were placed in a rack and placed in a vacuum oven with 16 vials, each of 100 pL CPTMS at approximately 45°C for 150 minutes. The gauge pressure was lowered to -1.0 bar, whereby the CPTMS evaporated, and the substrates were left for 150 minutes in the vapor. Next, the substrates were annealed in an oven at 80°C for 15 minutes.

[0205] Polymerization initiator grafting (Procedure 2):

[0206] Substrates, pre-cleaned as described above, were used for surface initiator-modification with (p- chloromethyl)phenyltrimethoxysilane (CPTMS) polymerization initiators using a chemical vapor deposition method. The substrates were placed in a rack and placed in a vacuum oven with 16 vials, each of 100 pL CPTMS at approximately 100°C. The gauge pressure was lowered to - 1.0 bar, whereby the CPTMS evaporated, and the substrates were left for 30 minutes in the vapor. Thereafter, the substrates were removed and left at ambient temperature for 24 h to anneal the attached silane polymerization initiator layer. Example 4

[0207] PHEMA surface polymer film formation on substrates of silicon and glass (Substrate 01- EG0140 (with poly(2-hydroxyethyl methacry late (PHEMA)) surface polymers)

[0208] 2 Si substrates (quadrants cut from 4" wafers) pre-cleaned as described in Si pre-cleaning procedure 1 (Example 1) and with polymerization initiators attached as described in procedure

[0209] 2 (Example 3), and 25 glass substrates (roughly 100 x 33 x 07 mm3, Coming Eagle Glass XG) pre-cleaned as described in Glass pre-cleaning procedure 3 (Example 2) and with polymerization initiators attached as described in Procedure 1 (Example 3)

[0210] In Container A, TPMA (100.8 mg) and CuCh 2H2O (16.32 mg) were dissolved in HEMA (8.4 m ) by sonicating. Dl-water (10.8 rnL) was added and the mixture shaken until homogeneous. The contents of Container A was added to Container B along with HEMA (369.6 mL), Dl-water (396 mL), and sodium carbonate buffer (IM. pH 9. 1, 330 mL), and sodium carbonate buffer (0. 1 M, pH 9.1, 66 mL). In Container C sodium ascorbate (4800.3 mg) was dissolved in Dl-water (18 rnL) by7vortexing. The contents of Container C was added to container B to form the reaction composition. The pH of the reaction composition was measured and adjusted to pH 8.8 through the addition of sulfuric acid. 6 minutes after adding the contents of Container C to Container B, the reaction composition was poured into a reaction container and the 2 Si substrates and the 25 glass substrates were submerged and left to react for 40 minutes. After 40 minutes the substrates were removed and dipped in water, flushed with water, sonicated in water for 5 minutes and sonicated in acetone for 5 minutes. Hereafter the substrates were air dried. The average dry film thickness of the surface polymers formed on the Si substrates was determined by ellipsometry and is 123.9 ± 5.4. The average dry film thickness of the surface polymer on Eagle Glass XG substrates is indicated by the thickness of the surface polymer on the Si substrates, since substrate transparency and backside reflections make ellipsometry7measurements and data modelling unreliable on the glass substrates.

[0211] Example 5

[0212] Method of preparing PHEMA surface polymers

[0213] 2 Si substrates (quadrants cut from 4’" yvafers) pre-cleaned as described in Si Pre-cleaning procedure 1 and with polymerization initiators attached as described in Polymerization initiator grafting procedure 2, and 12 glass substrates (roughly 50 x 50 x 0.7 mm3. Eagle XG) pre-cleaned as described in Glass Pre-cleaning procedure and yvith polymerization initiators attached as described in Polymerization initiator grafting procedure 1. The catalyst was prepared in Container A by mixing TPMA (105.3 mg), 8.88 mM CuCh 2H2O solution (11.3 mL), and MeCN (8.8 mL) in a vial and sonicating for 5 minutes to dissolve the TPMA. The contents of Container A was added to Container B along with HEMA (216.3 mL), DI water (666.3 mL), and MeCN (82.5 mL). In Container C sodium ascorbate (4000.3 mg) was dissolved in Dl-water (16.3 mL) by vortexing. The contents of Container C was added to Container B to form the reaction composition. 5 minutes after adding the contents of Container C to Container B, the reaction composition was poured into a reaction container and the 2 Si substrates and the 12 glass substrates were submerged and left to react for 120 minutes. After 120 minutes the substrates were removed and flushed with ethanol, flushed with water, sonicated in water for 5 minutes, flushed with acetone, and sonicated in acetone for 5 minutes. Hereafter the substrates were air dried. The average dry film thickness of the surface polymers formed on the Si substrates was determined by ellipsometry to be, on average, 53.5 ± 2.5 nm. The average dry film thickness of the surface polymer on Eagle Glass XG substrates is indicated by the average dry film thickness of the surface polymer on the Si substrates, since substrate transparency and backside reflections make ellipsometry measurements and data modelling unreliable on the glass substrates.

[0214] Example 6

[0215] Substrate EG0101 (with PGMA surface polymers cross-linked with allylamine):

[0216] 4 Si substrates pre-cleaned as described in Si Pre-cleaning procedure 1 and with polymerization initiators attached as described in Polymerization initiator grafting procedure 2, and 50 glass substrates pre-cleaned as described in Glass Pre-cleaning Procedure 3 with polymerization initiators attached as described in Polymerization initiator grafting procedure 1 were used for this example.

[0217] In Container A, 23.4 mL catalyst composing Me6TREN (1 11.2 pL), Dl-Water (23.3 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) was measured.

[0218] In Container B the catalyst activator was prepared by dissolving sodium ascorbate (6000 mg) in Dl-water (22.5 mL). In Container C, monomer (glycidyl methacrylate, 1 12.5 mL), Dl-Water (726.6 mL), and ethanol (615 mL) were mixed. The reaction mixture was obtained by adding the contents of Container A to Container C and mixing well. The contents of Container B were added to Container C and shaken well, to obtain the reaction composition. The combined contents of Container C were left for 5 minutes, after which it was poured into a reaction container. The 2 Si substrates and 25 Glass substrates were placed in a rack and submerged in the reaction liquid for 10 minutes. After 10 minutes the substrates (Si and glass) were removed and rinsed by dipping in Dl-water, and sonicating in Dl-water for 5 minutes, followed by sonicating in acetone for 5 minutes, and air drying. This procedure was repeated with a set of 2 new Si substrates and 25 glass substrates prepared as described in the beginning of this procedure, yielding a total of 4 Si substrates and 50 glass substrates functionalized with PGMA surface polymers. The average surface polymer dry film thickness was determined by spectroscopic ellipsometry measurements on the Si substrates, and are given in Table 1 .

[0219] Cross-linking of PGMA surface polymers with allylamine

[0220] The substrates were placed in a reaction container containing dimethylformamide (DMF, 1425 mL) and allylamine (75 mL), and the container was sealed and placed in an oil bath thermostated at 54°C. The reaction container was purged with argon for 45 minutes, and subsequently maintained at inert conditions by using a balloon filled with argon. After 22 hours the substrates were removed and dipped into DMF and sonicated in acetone for 10 minutes. The substrates were left to dry at ambient temperature and ambient pressure.

[0221] The average dry film thickness of the formed surface polymers was followed by measuring ellipsometry on the Si substrates, to give an indication of the average dry film thickness on the glass substrates as well, and are given in Table 1. An increase of -37% in thickness after the allylamine modification of PGMA indicates that the ring-opening reaction between allylamine and the epoxy functional groups in the repeat unit of the PGMA surface polymers took place, and given the w ell-established epoxy-amine chemistry', the inventors anticipate that the surface polymers are cross-linked to a certain extent after the reaction with allylamine.

[0222] Table 1. Surface polymer average dry' film thickness of PGMA and PGMA cross-linked with allylamine on Si substrate. Example 7

[0223] PHEA surface polymers

[0224] 14 Si substrates pre-cleaned as described in Example 1 (Si Pre-cleaning procedure 3) and with polymerization initiators attached as described in Example 3 (Polymerization initiator grafting procedure 2), and 14 glass substrates pre-cleaned as described in Example 2 (Glass Pre-cleaning Procedure 3) were used for this example, with polymerization initiators attached as described in Example 3 (Polymerization initiator grafting procedure 2).

[0225] The catalyst was prepared in Container A by mixing TPMA (84.2 mg), HEA (7 mL), and 8.88 mM CuCk 2H2O solution (9 mL) in a vial and sonicating for 5 minutes to dissolve the TPMA. In Container B the catalyst activator was prepared by dissolving sodium ascorbate (4002.0 mg) in Dl-water (15 mL). In Container C, the HEA (305 mL), and carbonate buffer (0.3 M, 660 mL) were mixed. The reaction composition was obtained by adding the contents of Container A to Container C and mixing well. The contents of Container B were added to Container C and shaken well, to obtain the reaction composition. The combined contents of Container C were left for 5 minutes to activate the reaction composition for surface polymer formation, after which it was poured into a reaction container. The 14 Si substrates were submerged in the reaction composition in the reaction chamber and left to form surface polymers for 60 minutes. After 60 minutes the Si substrates were removed and rinsed by dipping in Dl-water, and sonicating in Dl-water for 5 minutes, followed by sonicating in acetone for 5 minutes, and air drying. The 14 glass substrates were then submerged in the same reaction composition in the reaction chamber and left to form surface polymers for 60 minutes, after which they were withdrawn and rinsed by dipping in Dl-water. and sonicating in Dl-water for 5 minutes, followed by sonicating in acetone for 5 minutes, and air drying. The average dry7film thickness of the surface polymers formed on the Si substrates was determined by ellipsometry' to be, on average, 35.5 ± 0.3 nm. The average dry film thickness cannot be determined by ellipsometry on the glass substrates.

[0226] Example 8

[0227] Polysty rene surface polymers

[0228] 10 Si substrates (quadrants cut from 4” wafers) pre-cleaned as described in Si Pre-cleaning procedure 3 and with polymerization initiators attached as described in Polymerization initiator grafting Procedure 2, and 4 glass substrates pre-cleaned as described in Glass Pre-cleaning 3 with polymerization initiators attached as described in Polymerization Initiator grafting Procedure 2 were used. In Container A, 45 rnL catalyst composing Me6TREN (213.8 pL), Dl-Water (44.8 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) was added, along with Dl-Water (690 mL), ethanol (720 mL), and monomer (styrene, 7.5 rnL), and mixed by shaking. In container B sodium ascorbate (6000 mg) was dissolved in DI water (22.5 mL) by vortexing. The contents of Container B were added to Container A to form the reaction composition. 5 minutes after adding the contents of Container B to Container A, the reaction composition was poured into a reaction container and a rack holding the 10 Si substrates and the 4 glass substrates was submerged and left for 80 minutes. After 80 minutes the rack holding the substrates was removed and dipped in Dl-water, flushed with Dl-water, sonicated in Dl-water for 5 minutes and sonicated in acetone for 5 minutes. Hereafter the substrates were air dried. The average dry film thickness of the surface polymers formed on the Si substrates was determined by ellipsometry to be 57.4 ± 9.0 nm. The average dry film thickness of the surface polymers cannot be determined by ellipsometry on glass substrates.

[0229] Example 9

[0230] PHEMA-PEGDMA copolvmer surface polymers

[0231] 2 Si substrates pre-cleaned as described in Si Pre-cleaning 1 and with polymerization initiators attached as described in Polymerization initiator grafting Procedure 2, and 25 glass substrates precleaned as described in Glass Pre-cleaning 3 were used for this example, with polymerization initiators attached as described in Polymerization initiator grafting Procedure 1.

[0232] The catalyst was prepared in Container A by mixing TPMA (100.8 mg), acetonitrile (8.5 rnL), and 8.88 mM CuCb 2H2O (aq.) solution (10.7 mL) in a vial and sonicating for 5 minutes to dissolve the TPMA. In Container B the catalyst activator was prepared by dissolving sodium ascorbate (4800.4 mg) in Dl-water (18 mL). In Container C, HEMA (258.6 rnL), EGDMA (8.2 mL), DI water (798 mL), and acetonitrile (102 mL) were mixed. The contents of Container A were added to Container C and mixed well. The contents of Container B were added to Container C and shaken well, to obtain the reaction composition. The combined contents of Container C were left for 5 minutes, after which it was poured into a reaction container. The 2 Si substrates and the 25 glass substrates were submerged in the reaction composition in the reaction chamber and left to form surface polymers for 40 minutes. After 40 minutes the Si and glass substrates were removed and rinsed by dipping in Dl-water, and sonicating in Dl-water for 5 minutes, followed by sonicating in acetone for 5 minutes, and air drying. The average dry film thickness of the surface polymers formed on the Si substrates was determined by ellipsometry to be, on average, 31.2 ± 0.6 nm. The average dry film thickness cannot be determined on glass substrates.

[0233] Example 10

[0234] Formation of PHEMA surface polymers modified with adipoyl chloride.

[0235] 1 Si substrate pre-cleaned as described Si Pre-cleaning ) and with polymerization initiators attached as described in Polymerization Initiator Grafting Procedure 2, and 3 glass substrates (50 x 50 x 0.7 mm3) pre-cleaned as described in Glass Pre-cleaning 3 were used for this example, with polymerization initiators attached as described in Polymerization initiator grafting Procedure 2.

[0236] The catalyst was prepared in container A by mixing TPMA (84.2 mg), acetonitrile (7 mL), DI- water (9 mL), and CuCh 2H2O (13.6 mg) in a vial and sonicating for 5 minutes to dissolve the TPMA and CuCk 2H2O. In Container B the catalyst activator was prepared by dissolving sodium ascorbate (4000 mg) in Dl-water (15 mL). In Container C, HEMA (220 mL), DLwater (665 mL), and acetonitrile (85 mL) w ere mixed. The contents of Container A were added to Container C and mixed well. The contents of Container B were added to Container C and shaken well, to obtain the reaction composition. The combined contents of Container C were left for 5 minutes, after which it was poured into a reaction container. The 1 Si substrate and the 3 glass substrates w ere submerged in the reaction composition in the reaction chamber and left to form surface polymers for 80 minutes. After 80 minutes the Si and glass substrates were removed and rinsed by dipping in Dl-water, and sonicating in Dl-water for 5 minutes, followed by sonicating in acetone for 5 minutes, and air drying. The average dry film thickness of the surface polymers formed on the Si substrate was determined by ellipsometry to be 34.2 ± 0.4 nm. The average dry film thickness cannot be determined on glass substrates by ellipsometry.

[0237] Modification of PHEMA surface polymers through reaction with adipoyl chloride

[0238] The hydroxyl moiety of the PHEMA repeating unit is expected to be reactive with the acid chloride moiety of adipoyl chloride. Having tw o acid chlorides enables adipoyl chloride to react with two individual hydroxyl moieties in the PHEMA surface polymer, effectively rendering it a cross-linking agent, meaning that the PHEMA surface polymer will be cross-linked upon reaction with adipoyl chloride. Dimethylformamide (195.6 mL), 4-dimethylaminopyridine (122.2 mg), and triethylamine (1.4 mL) were added to a container and sonicated until the solids were dissolved. Adipoyl chloride (4.4 mL) was then slowly added and mixed well. This reaction mixture was poured into a reaction container and the Si substrate with PHEMA surface polymers and the 3 glass substrates with PHEMA surface polymers were submerged in the reaction mixture. After 10 minutes the substrates were retrieved, flushed with DCM, sonicated in DCM for 5 minutes, and in acetone for 5 minutes and left to air dry. After the reaction with adipoyl chloride, the PHEMA-adipoyl surface polymer average dry film thickness on the Si substrate had increased to 41.5 ± 0.5 nm, indicating successful reaction between the hydroxyl moieties and the acid chlorides of adipoyl chloride.

[0239] Example 11

[0240] Formation of PHEMA-block-PGMA surface block-

[0241] In this example the formation of block-copolymers consisting of a first block of PHEMA and a second block of PGMA is shown. The inventors hypothesize that the block structure may be beneficial for binding first metal ions such as palladium in the inner PHEMA surface polymer, while retaining the reactive and cross-linking prone outer PGMA surface polymer for interlocking of the formed second metal layer, e.g., copper layer. First a PHEMA surface polymer was formed, and subsequently a PGMA surface polymer was grown from the viable chain ends of the PHEMA surface polymers, yielding a block copolymer surface polymer structure.

[0242] PHEMA surface polymer formation

[0243] 3 Si substrates pre-cleaned as described Si Pre-cleaning 1 and with polymerization initiators attached as described in Polymerization initiator grafting Procedure 2, and 7 glass substrates (50 x 50 x 0.7 mm3) pre-cleaned as described in Glass Pre-cleaning 3 were used for this example, with polymerization initiators attached as described in Polymerization initiator grafting Procedure 2.

[0244] A pre-solution of TPMA was prepared by mixing TPMA (84. 1 mg) in HEMA (7 mL). The catalyst was prepared in Container A by mixing the TPMA pre-solution (70 pL, using a finnpipette), HEMA (7 mL). Dl-water (9 mL), and 8.88 mM CuCh 2H2O (aq.) solution (90 pL using a finnpipette) in a vial and sonicating for 5 minutes to dissolve the TPMA and CuCh 2H2O. In Container B the catalyst activator was prepared by dissolving sodium ascorbate (4000 mg) in Dl-water (15 mL). In Container C. HEMA (220 mL), Dl-water (665 mL). and acetonitrile (85 mL) were mixed. The contents of Container A were added to Container C and mixed well. The contents of Container B were added to Container C and shaken well, to obtain the reaction composition. The combined contents of Container C were left for 5 minutes, after which it was poured into a reaction container. The 1 Si substrate and the 3 glass substrates were submerged in the reaction composition in the reaction chamber and left to form surface polymers for 80 minutes. After 80 minutes the Si and glass substrates were removed and rinsed by dipping in Dl-water, and sonicating in Dl-water for 5 minutes, followed by sonicating in acetone for 5 minutes, and air drying. The average dry film thickness of the PHEMA surface polymers formed on the Si substrate was determined by ellipsometry to be 77.1 ± 6.8 nm. The average dry film thickness cannot be determined on glass substrates by ellipsometry.

[0245] Formation of PGMA block from viable chain ends of the PHEMA surface polymers

[0246] Using the 1 Si substrate and 3 glass substrates with PHEMA surface polymers, a second surface polymer block of PGMA was formed as described below.

[0247] The catalyst was prepared in Container A by mixing TPMA (84.2 mg), ethanol (7 mL), and 8.88 mM CUC12'2H2O solution (9 mL) in a vial and sonicating for 5 minutes to dissolve the TPMA. In Container B the catalyst activator was prepared by dissolving sodium ascorbate (4000.2 mg) in Dl-water (15 mL). In Container C, GMA (75 mL), Dl-water (150 mL), and ethanol (744 mL) were mixed. The contents of Container A were added to Container C and mixed well. The contents of Container B were added to Container C and shaken well, to obtain the reaction composition. The combined contents of Container C were left for 5 minutes, after which it was poured into a reaction container. The 1 Si substrate and the 3 glass substrates were submerged in the reaction composition in the reaction chamber and left to form surface polymers for 60 minutes. After 60 minutes the Si and glass substrates were removed and rinsed by dipping in Dl- water, and sonicating in Dl-water for 5 minutes, followed by sonicating in acetone for 5 minutes, and air drying. The average dry film thickness of the PHEMA-block-PGMA surface polymers on the Si substrate increased to 87.7 ± 8.2 nm, determined by ellipsometry . The average dry film thickness cannot be determined on glass substrates by ellipsometry. The increased thickness after the second surface polymerization indicates formation of a block copolymer surface polymer with a first block PHEMA and a second block PGMA.

[0248] Example 12

[0249] PHEMA-BiBB-PHEMA surface polymers In this example, the formation of a surface polymers by forming first polymer molecules of PHEMA, and subsequently attaching a polymerization initiator, BiBB, to the pendant hydroxyl moiety of the repeating unit of the PHEMA surface polymer, and forming second polymer molecules of PHEMA surface polymer from the polymer molecule-bound BiBB polymerization initiator is shown.

[0250] Formation of surface polymer of first polymer molecules of PHEMA

[0251] 10 Si substrates pre-cleaned as described in Si Pre-cleaning 1 and with polymerization initiators attached as described in Polymerization initiator grafting Procedure 2, and 11 glass substrates (50 x 50 x 0.7 mm3) pre-cleaned as described in Glass Pre-cleaning 3 were used, with polymerization initiators attached as described in Polymerization initiator grafting Procedure 2.

[0252] The catalyst was prepared in Container A by mixing TPMA (126.0 mg), HEMA (10.5 mL), and 8.88 mM CuCh 2H2O solution (13.4 mL) in a vial and sonicating for 5 minutes to dissolve the TPMA. In Container B the catalyst activator was prepared by dissolving sodium ascorbate (6000.6 mg) in Dl-water (22.5 mL). In Container C, HEMA (462 mL), Dl-water (495 mL), and carbonate buffer (91.7 g NaHCOs and 11.5 g Na2COs in 2000 mL Dl-water) (495 mL) were mixed. The contents of Container A were added to Container C and mixed well. The contents of Container B were added to Container C and shaken well, to obtain the reaction composition. The combined contents of Container C were left for 5 minutes, after which the pH of the reaction composition was measured and adjusted to be within the range of pH 8.4 to pH 9.2, through the addition of sulfuric acid. The reaction mixture was then poured into a reaction container. The 10 Si substrate and the 1 1 glass substrates were submerged in the reaction composition in the reaction chamber and left to form surface polymers for 40 minutes. After 40 minutes the Si and glass substrates were removed and rinsed by dipping in Dl-water, and sonicating in Dl-water for 5 minutes, followed by sonicating in acetone for 5 minutes, and air drying. The average dry film thickness of the surface polymers formed on the Si substrates was determined by ellipsometry to be 123.1 ± 2.7 nm. The average dry film thickness of the surface polymers on the glass substrates cannot be determined by ellipsometry.

[0253] Second polymerization-initiator functionalization of PHEMA surface polymers

[0254] The Si and glass substrates with PHEMA surface polymers as described above were used. A reaction mixture was formed by adding first DMAP (795.2 mg), triethylamine (9.5 mL), and DMF (1210 mL) to a container and mixing well. BiBB (80.6 mL) was then added and the reaction mixture was mixed well, and added to a reaction chamber. The 10 Si substrate with PHEMA surface polymer and the 11 glass substrates with PHEMA surface polymer were then submerged in the reaction mixture and left for 10 minutes after which they were withdrawn and flushed with DCM, flushed with acetone, sonicated in acetone for 5 minutes and finally dried in a conventional oven at 80°C for 2 minutes. The reaction between the hydroxy moieties on the PHEMA surface polymer and the BiBB molecules as evidenced by an increase in average dry film thickness, attributed to the covalent attachment of the second polymerization initiator BiBB. The average dry film thickness of the PHEMA-BiBB surface polymer on the Si-substrates was 175.5 ± 5.6 nm as measured by ellipsometry. The average dry film thickness of surface polymers on glass substrates cannot be determined by ellipsometry'. of PHEMA from the BiBB

[0255] The Si and glass substrates with PHEMA-BiBB surface polymers were used.

[0256] The catalyst was prepared in Container A by mixing TPMA (109.2 mg), HEMA (9.1 mL), and CuCh 2H2O (18.2 mg) in a vial and sonicating for 5 minutes to dissolve the TPMA and CuCh 2H2O. In Container B the catalyst activator was prepared by dissolving sodium ascorbate (5200.7 mg) in Dl-water (19.5 mL). In Container C, HEMA (400 mL), Dl-water (429 mL), and carbonate buffer (91.7 g NaHCCh and 11.5 g Na2COs in 2000 mL Dl-water) (429 mL) were mixed. The contents of Container A were added to Container C and mixed well. The contents of Container B were added to Container C and shaken well, to obtain the reaction composition. The combined contents of Container C were left for 5 minutes, after which the pH of the reaction composition was measured and adjusted to be pH 8.8, through the addition of sulfuric acid. The reaction mixture was then poured into a reaction container. The 10 Si substrate and the 11 glass substrates with PHEMA-BiBB surface polymers were submerged in the reaction composition in the reaction chamber and left to form surface polymers from the BiBB polymerization initiator sites for 10 minutes. After 10 minutes the Si and glass substrates were removed and rinsed bydipping in ethanol, flushed with ethanol, dipped in Dl-water, flushed with Dl-water, then sonicated in Dl-water for 5 minutes, and sonicated in acetone for 5 minutes, followed by air drying. The average dry7film thickness of the PHEMA-BiBB -PHEMA surface polymers formed on the Si substrates was determined by ellipsometry to be 1206.2 ± 35.1 nm. The average dry film thickness on the glass substrates cannot be determined by ellipsometry.

[0257] Example 13

[0258] PHEMA-BiBB-PHEA surface polymers

[0259] Surface polymers were formed by forming first polymer molecules of PHEMA, and subsequently attaching a polymerization initiator, BiBB, to the pendant hydroxyl moiety' of the repeating unit of the PHEMA, followed by forming second polymer molecules of PHEA from the surface polymer-bound BiBB polymerization initiator.

[0260] PHEMA surface polymer formation

[0261] 2 Si substrates pre-cleaned as described in Si Pre-cleaning 3 and with polymerization initiators attached as described in Polymerization initiator grafting Procedure 2, and 12 glass substrates (100 x 25 x 0.7 mm3) pre-cleaned as described in Glass Pre-cleaning 3 were used for this example, with polymerization initiators attached as described in Polymerization initiator grafting Procedure 2.

[0262] A pre-sol uti on of TPMA was prepared by mixing TPMA (83.8 mg) in HEMA (7 mL). The catalyst was prepared in Container A by mixing the TPMA pre-solution (70 pL. using a finnpipette), HEMA (6.86 mL), Dl-water (8.82 mL), and 8.88 mM CuCE 2H2O solution (180 pL, using a finnpipette) in a vial and sonicating for 5 minutes to dissolve the TPMA. In Container B the catalyst activator was prepared by dissolving sodium ascorbate (4000.2 mg) in Dl-water (15 mL). In Container C, HEMA (308 mL). Dl-water (330 mL), and carbonate buffer (688.0 g NaHCO? and 85.9 g Na2CCh in 15 L Dl-water, 330 mL) were mixed. The contents of Container A were added to Container C and mixed well. The contents of Container B were added to Container C and shaken well, to obtain the reaction composition. The combined contents of Container C were left for 5 minutes, after which the pH of the reaction composition was measured and adjusted to be pH 8.8, through the addition of sulfuric acid. The contents of Container C were then poured into a reaction chamber and the 2 Si substrates and the 12 glass substrates were submerged in the reaction composition in the reaction chamber and left to form surface polymers for 60 minutes. After 60 minutes the Si and glass substrates were removed and rinsed by dipping in Dl-water, and sonicating in Dl-water for 5 minutes, followed by sonicating in acetone for 5 minutes, and air drying. The average dry film thickness of the PHEMA surface polymers formed on the Si substrate was determined by ellipsometry' to be 146.4 ± 0.7 nm. Average dry' film thickness cannot be determined on glass substrates by ellipsometry. Functionalization of PHEMA surface polymers with PHEMA-bound polymerization initiator

[0263] BiBB to obtain PHEMA-BiBB surface polymers

[0264] The Si and glass substrates with PHEMA surface polymers as described above were used.

[0265] The reaction mixture was formed by adding first DMAP (610.8 mg), triethylamine (7.3 mL), and DMF (931 mL) to a container and mixing well. BiBB (62 mL) was then added and the reaction mixture was mixed well, and added to a reaction container. The 2 Si substrate with PHEMA surface polymer and the 12 glass substrates with PHEMA surface polymer were then submerged in the reaction liquid and left for 10 minutes after which they were withdrawn and flushed with DCM, flushed with acetone, sonicated in acetone for 5 minutes and finally air dried. The reaction between the hydroxy moieties on the PHEMA surface polymer and the BiBB molecules was evidenced by an increase in average dry film thickness, attributed to the covalent attachment of the polymerization initiator to the PHEMA surface polymer. The average dry film thickness of the PHEMA-BiBB surface polymer on the Si-substrates w as 242.6 ± 2.0 nm, as measured by ellipsometry. The average dry film thickness could not be determined by ellipsometry on the glass substrates.

[0266] Formation of PHEA surface polymer from the BiBB polymerization initiator sites to form PHEMA-BiBB-PHEA surface polymers

[0267] The 2 Si and 12 glass substrates with PHEMA-BiBB surface polymers as described above were used.

[0268] The catalyst was prepared in Container A by mixing TPMA (84.9 mg), HEA (7 mL), 8.88 mM CuCh 2H2O solution (9 mL) in a vial and sonicating for 5 minutes to dissolve the TPMA. In Container B the catalyst activator was prepared by dissolving sodium ascorbate (4001.0 mg) in Dl-water (15 mL). In Container C, HEA (305 mL), Dl-water (330 mL), and carbonate buffer (91.7 g NaHCCh and 1 1.5 g Na2CCh in 2000 mL Dl-water) (330 mL) were mixed. The contents of Container A w ere added to Container C and mixed well. The contents of Container B were added to Container C and shaken well, to obtain the reaction composition. The combined contents of Container C were left for 5 minutes, after which the pH of the reaction composition was measured and adjusted to be pH 8.9, through the addition of sulfuric acid. The reaction composition was then poured into a reaction container. The 2 Si substrate and the 12 glass substrates with PHEMA-BiBB surface polymers w ere submerged in the reaction composition in the reaction chamber and left to for 40 minutes. After 40 minutes the Si and glass substrates were removed and rinsed by dipping in Dl-water, sonicated in Dl-water for 5 minutes, flushed with acetone, and sonicated in acetone for 5 minutes, followed by air drying. The average dry film thickness of the PHEMA-BiBB-PHEA surface polymers formed on the Si substrates was determined by ellipsometry to be, on average, 827.3 ± 10.7 nm. The average dry film thickness could not be determined by ellipsometry on the glass substrates.

[0269] Example 14

[0270] Electroless (Eless) copper (Cu) deposition - process

[0271] Substrates with surface polymer films prepared as described in Example 4 through to Example 13 (both included) were used for electroless copper deposition as described in this example. The inventors note that when attempting deposition of electroless copper on a blank piece of glass (Eagle glass XG), no or very sparse copper layer formed, and any small specks of formed copper layer would immediately flake off of the glass substrate under regular substrate handling.

[0272] The procedure for electroless deposition of copper is described further below.

[0273] Sensitization step (Pd seeding): Aqueous NaOH (1.5 mL, 50% w / w from ACME analytical) was added to 900 mL Dl-water. Then 50 mL of Uyemura ALCUP MAT-433-SP (Product Code 9100468) was added, followed by the addition of water until reaching a total volume of 1 L. The solution was heated to 40°C for 1 hour while stirring, and the pH was adjusted to 10.5 with NaOH. Substrates placed vertically in a PTFE rack were added to the reaction composition for a defined sensitization time (See “Sensitization Time” in Table 2 below), with continued stirring. Substrates were post-cleaned by two consecutive dips into separate vessels containing Dl-water while stirring at ambient temperature for 2 minutes and 1 minute, respectively.

[0274] In the above procedure, the sensitization time in which substrates are subjected to the reaction composition may be varied based on the affinity of the substrate surface polymer film to Pd, such as sensitization time being 2.5 hours, 3 minutes, or 30 minutes.

[0275] Reduction step (reduction of Pd ions to Pd(0)): Following the sensitization step, 10 mL of Uyemura ALCUP MAB-435-D was added to 600 mL Dl-water. Then, 50 mL of Uyemura ALCUP MAB-435-C was added and the solution was mixed well. Then, 17mL of Uyemura ALCUP MAB-435-AX was added and the solution was mixed well. Dl-water was added until reaching a total volume of 1 L, and the pH of this bath was determined to 6.5. The reaction composition was heated to 35°C while stirring. Substrates placed vertically in a PTFE rack were added to the reaction composition for a defined time (See “Reduction Time” in Table 2 below), with continued stirring. Substrates were post-cleaned by two consecutive dips into separate vessels containing Dl-water while stirnng at ambient temperature for 2 minutes and 1 minute, respectively.

[0276] In the above procedure, the time with which substrates are subjected to the reaction composition may be varied based on the affinity of the substrate surface polymer film to Pd, such as reduction time = 1 hour, 10 minutes, 2 minutes, or 3 hours.

[0277] Accelerator step: Following the reduction step, 50 mL of Uyemura ALCUP MEL-437-M was added to 950 mL Dl-water to reach a total volume of 1 L. The pH was determined to 2. Substrates placed vertically in a PTFE rack were added to the reaction composition for 1 minute with continued stirring at ambient temperature. Substrates were recovered and immediately subjected to electroless copper deposition (see below).

[0278] Electroless Copper deposition: To 650 mL of Dl-water. the following components were added in the mentioned order. Between each component addition, the mixture was mixed thoroughly. 1) 100 mL of Uyemura THRU-CUP PEA-531-A. 2) 50 mL of THRU-CUP PEA-531-B. 3) 14 mL of THRU-CUP PEA-531-C. 4) 12 mL of THRU-CUP PEA-531-D. 5) 50 mL of THRU- CUP PEA-531-E. 6) 5 mL of formaldehyde 37% (15% methanol) from ACME analytical. 7) Dl- water was added to a total volume of 1 L, and the reaction composition was heated to 36°C. Substrates w ere recovered from the prior accelerator step and directly subjected to the electroless reaction composition vertically in a PTFE rack for 20 minutes while agitating by rocking (± 2.5 cm), shocking (agitator with a frequency of 1 cycle per 6 seconds), and bubbling with clean dryair (CDA) at 50-100 mL / min for a 1 L solution. Substrates were post-cleaned by two consecutive dips into separate vessels containing Dl-water while stirring at ambient temperature for 2 minutes and 1 minute, respectively.

[0279] After the electroless copper (Cu) deposition, the deposited Cu layers were evaluated for continuity over the substrate surface using optical microscopy and were all found to be satisfactory- with no or limited defects such as uneven layers, blisters, and flaking. Following the electroless deposition of Cu, the substrates were annealed at 300°C (vacuum) for 30 minutes using a Yield Engineering Systems PB-450 vacuum cure system. A ramp rate of approximately 3.3°C per minute was used, and the total anneal time was approximately 275 minutes. The full thermal anneal temperature profile is shown in Fig. 8. Thus, a device structure comprising a substrate with surface polymers, Pd seed layer on and within surface polymer structure, and copper deposited within and on surface polymer structure using electroless deposition was formed.

[0280] In the above procedure, the temperature of annealing as well as heating and cooling rate may be varied based on surface polymer properties including thermal stability. For some surface polymers, lower temperature of annealing such as 250°C as well as lower heating and cooling rate such as 1°C per minute may lead to improved stability .

[0281] Following the procedures laid out in the above description, electroless copper deposition was carried out on the glass substrates prepared in Examples 4 and Examples 6-13. For each surface polymer type an optimized set of reaction times for the Sensitization step (Pd-seeding) (sensitization time) and the Reduction Step (reduction of Pd ions to Pd(0)) (reduction time). The reaction times for each surface polymer are compiled in Table 2 below.

[0282] Table 2. Type of surface polymer, Sensitization time, and Reduction time, for the electroless deposition of copper layer on different surface polymers film substrates.

[0283] Example 15 Adhesion of electroless copper (Cu) and mechanical integrity of device structure

[0284] Adhesion of the electroless Cu to the surface polymer film and the mechanical integrity of the substrates of Example 14 were measured using a Mark-10 F305 Test Frame with 90-degree peel test fixture. The following procedure was used to evaluate adhesion of the copper layer to glass substrates with surface polymer:

[0285] 1. Tesa 4965 double-sided tape was used to attach the substrate to an Aluminum metal plate (2 inches by 4 inches).

[0286] 2. A single layer of 3M 111 adhesion promoter solution was applied to the area to be tested using a cotton applicator and the adhesion promotor solution was allowed to dry for 1 minute.

[0287] 3. 3M VHB tape with a width of 1 cm was applied to the area to be tested (covered with the adhesion promoter solution) all the way across the substrate. The original backing tape was peeled off. 4. 3M GT tape with a width of 1 cm was applied exactly to the 3M VHB as a stronger backing tape. A sufficient amount of the GT tape was left extending off the surface of the substrate for the peel testing clamp to grip.

[0288] 5. The metal plate was slid into the fixture on the substrate testing stage.

[0289] 6. The peel testing clamp was lowered using the tester’s interface. The extended GT tape was inserted into the clamp and the clamp was hand-tightened.

[0290] 7. The test was run with a peel rate of 100 mm / min (this peel rate may be varied and impact the measured peel strength).

[0291] Fig. 10 shows peel test data for electroless copper on a glass substrate with PHEMA surface polymers prepared as described in Example 5, and with copper layer prepared as described in Example 14, with sensitizer time of 5 minutes and reduction time of 3 minutes. No peel of copper was observed and the tape was seen to stretch above 17 N / cm, which implied an adhesion strength for the electroless copper of at least 17 N / cm.

[0292] Fig. 11 shows peel test data for electroless copper on a glass substrate with PGMA-allylamine surface polymers prepared as described in Example 6, and with copper layer prepared as described in Example 14, with Sensitizer time of 5 minutes and Reduction time of 3 minutes, with both 3M GT (upper plot) and 3M VHB tape (low er plot), where peeling started around 2.5 cm for the GT tape and around 2.8 cm for the VHB tape. When peeling, the adhesion w as determined to approximately 6.5 N / cm.

[0293] Fig. 12 shows peel test data for electroless copper on a glass substrate with PGMA-allylamine surface polymer prepared as described in Example 6, and with copper layer prepared as described in Example 14 with a Sensitizer time of 150 minutes and Reduction time of 60 minutes. No peeling was observed, and the tape was seen to stretch above 23 N / cm, which indicates an adhesion strength for the electroless copper of at least 23 N / cm.

[0294] Table 3 below7compiles the peel strength measured for electroless copper layer deposited on glass substrates using various surface polymer types as adhesion layers and primers for the copper deposition. The substrate preparation and the mechanical testing follows the process laid out at the beginning of this example. Table 3. Surface polymer type, corresponding Sensitization time and Reduction time and the result of tape peel test on the deposited electroless copper layer.

[0295] * Exact number not obtained due to tape deformation.

[0296] ** Peel data obtained without annealing the deposited electroless copper layer. Exact number not obtained due to tape deformation.

[0297] Notably, the surface polymers promoted adhesion so strong that the tape peel test fails to remove the copper layer, and thus the reported peel strength can only be taken as a minimum value for the adhesion of the copper layer to the underlying substrate, and the true peel strength of the copper lay are be expected to be higher than the reported values in Table 3. The variation in the reported peel strength is ascribed to differences in the failure mode of the applied GT tape for the different substrates: in some cases, the tape was simply peeled off the copper layer, and in other cases some of the adhesive from the GT tape was left on the copper layer as residues, accounting for the apparent large variations in the minimal peel strength reported in Table 3. The fact that the adhesive of the tape sometimes fails, is a testament to the strong bonding of the copper layer to the glass substrate promoted by surface polymers.

[0298] The inventors note that a wide array of surface polymer films subjected to electroless copper deposition all adhered electroless deposited copper well. The surface polymer film included structures such as polar and hydroxyl-functionalized PHEMA surface polymer, hydrophobic poly(styrcne) surface polymers, and cross-linked surface polymers such as PGMA-allylamine surface polymer films. Thus, the versatility and applicability of the surface polymers are excellent. The inventors note that optimization with regard to sensitization time and reduction time for the electroless copper deposition may be further optimized for each surface polymer. For example, it is noted that in case of the cross-linked PGMA-allylamine a sensitization time of 150 minutes and reducer time of 60 minutes led to stronger copper adhesion than a shorter sensitization time and reduction time (5 and 3 minutes, respectively). The inventors believe palladium ions, reduction of palladium, and other components of the electroless copper deposition process may to some extent be dependent on the design of the surface polymer film.

[0299] Furthermore, the inventors note that attempts to deposit electroless copper on an un-modified Glass substrate (no initiator or surface polymer) failed, indicating the advantage of having the surface polymers assisting in successful formation and adhesion of electroless copper.

[0300] Example 16

[0301] Evaluation of electroless deposited copper by stud pull testing

[0302] In this example the inventors demonstrate strong bonding between the electroless deposited copper and the underlying substrate through stud pull testing. Encouraged by the fact that the tape peel tests in Example 15 did not lead to failure between the copper layer and the substrate, the inventors believe it helpful to demonstrate the adhesion of the copper layer by yet another mechanical test method, namely stud pull tests.

[0303] Substrate preparation

[0304] The substrates used in this example were prepared with PHEMA surface polymers on glass substrates, as described in Example 4. and prepared with electroless copper layer deposited as described in Example 14, with a sensitization time of 5 minutes and a reduction time of 3 minutes. Stack assembly for stud pull testing

[0305] The glass substrates with PHEMA surface polymers and deposited electroless copper layer were assembled into a stack for stud pull testing. Prior to stack assembly the backside of the glass substrate also having electroless copper deposited (the side opposite to the side on which the dolly is attached) was roughened using a 3M Scotch Brite abrasive pad. The stack was then assembled by bonding the glass substrate, with PHEMA surface polymers and deposited electroless copper, to an AISI316 stainless steel backing substrate (45 x 45 x 6 mm3) using an epoxy adhesive (EP 907 Epoxy from Permalock), and bonding an aluminum dolly (0 = 10 mm contact area) to the side of the glass substrate not bonded to the stainless steel backing (see Figure 13 for stack structure). The epoxy adhesive was cured by placing the assembled stack in a conventional oven at 60°C for 23 minutes and leaving the assembled stack at ambient conditions over night, to give a total rest time from assembly of 24 hours before stud pull testing.

[0306] Stud pull testing

[0307] To evaluate the adhesion of the electroless copper deposited on the glass substrate with PHEMA surface polymers, a PosiTest AT-A instrument was used. The actuator of the pull-instrument was attached to the head of the aluminum dolly and the measurement initiated by programming the instrument to build pressure at a rate of 4 MPa per second, until either of substrate failure or maximum pressure of 96 MPa was reached. The pressure (at failure) was noted.

[0308] A total of 6 glass substrates with PHEMA surface polymers and electroless copper was tested in this fashion, leading to an average pull-off strength of 41.6 ± 5. 1 MPa. As desired for a stud pull test, in all cases the stack breaks in the interface between copper and glass, enabling the inventors to report on the pull-off strength of the copper layer. As mentioned in Example 15, when no surface polymer is present, the deposition of electroless copper fails and such substrates could not be subjected to peel testing or stud pull testing. The stud pull testing of a substrate having a surface polymer film of PHEMA promoted a very strong adhesion to the substrate in stark contrast to substrate with no surface polymer film (Example 15).

[0309] Surprisingly, the inventors have found that it was not necessary to roughen the substrates to achieve good adhesion prior to electroless deposition of copper to achieve adhesion, nor was it necessary to deposit e.g. a titanium metal primer layer through laborious PVD routines, as commonly applied in e.g., the semiconductor industry. The inventors believe that this attractive trait of the surface polymers may be due to the surface polymers being covalently anchored to the surface, and also due to the versatile chemical functional groups which present on those surface polymers, which may be well suited for bonding metals on and within the surface polymer film.

[0310] Example 17

[0311] Deposition of electroless copper on TGV substrate with PHEMA surface polymers

[0312] For this experiment, a TGV substrate (through-glass via, Schott BF33 1 cm x 1 cm and with a thickness of 0.45 mm was used. The substrate had a total of 4 die sets, 2 with 100 micron VIAs (pitch 300 pm and 150 pm, respectively) and 2 with 50 micron VIAs (pitch 300 pm and 150 pm, respectively).

[0313] TGV Substrate with PHEMA surface polymers: A through glass via (TGV) substrate (1 x 1 cm2, 0.45 mm thickness (Schott BF33)) cleaned according to Glass Pre-cleaning 2 procedure and with polymerization initiators attached according to Polymerization initiator grafting procedure 2. The substrates where then dipped in and out of 1000 mL sonicated Dl-water and ‘’rocked” back and forth in the sonicated Dl-water 5 times. The substrates were kept immersed in the sonicated DI- water until surface polymer formation. The reaction composition for surface polymer formation was prepared as follows: In container A TPMA ligand (84.1 mg) was dissolved in 7 mL HEMA monomer, followed by addition of 9 mL CuCL solution (made of 1.5139 g CUCI2 2H2O in 1000 mL Dl-water). In Container B, 4000 mg NaAsc was dissolved in 15 mL Dl-water using a vortex mixer. In Container C, 308 mL HEMA monomer, 462 mL Dl-water and 198 mL 1 M sodium carbonate / sodium bicarbonate buffer (pH 8.8) were mixed. The contents of Container A were added to Container C and mixed well. The contents of Container B was then added to Container C, Container C was shaken well, and left for 5 minutes to activate the reaction composition for surface polymer formation. Following activation, the pH was adjusted to 8.8 by addition of sulfuric acid. The substrates were transferred to the reaction composition and the container was capped. The reaction composition with the substrates was sonicated for 1 minute and left for 39 minutes to form surface polymers from the polymerization initiator sites on the substrates. Following surface polymerization, the substrates were transferred to a container with sonicated Dl-water, dipped in and out of the Dl-water 5 times, followed by rinsing with EtOH and Dl-water. The substrates were transferred to another container with sonicated Dl-water and sonicated for 1 minute. The substrates were rinsed with acetone and transferred to a container with sonicated acetone. The substrates were sonicated in the acetone for 1 minute, withdrawn and left to dry at ambient conditions (ambient pressure, ambient temperature). The TGV substrate was subjected to an electroless (Eless) copper (Cu) deposition procedure including a sensitization step, reduction step, accelerator step, and electroless copper deposition step as described in Example 14 with a sensitization time of 5 minutes and a reduction time of 3 minutes.

[0314] After the electroless copper deposition, the deposited Cu layer was evaluated by Xray imaging.

[0315] Fig. 14 shows an Xray image of the TGV substrate after electroless deposition of copper. The four die sets are top left: 50 micron / pitch 150, top right: 100 micron / pitch 150, bottom left: 50 micron / pitch 150, and bottom right: 100 micron / pitch 300. As can be seen, an excellent Eless copper deposition was achieved for all VIAs. The Eless copper is deposited within and on the surface polymer film grafted from the TGV surface. The estimated defectivity post-Eless copper deposition is less than 1 % (defined as “number of incomplete deposition" divided by “total number of VIAs”).

[0316] Fig. 15 is a zoom of top right: 100 micron / pitch 150 of Fig. 14. The dark curved lines are Eless copper deposited along the inside of the TGV walls on and in the surface polymer film. No defectivities were observed.

[0317] Fig. 16 is a zoom of top left: 50 micron / pitch 150 of Fig. 14. The dark curved lines are Eless copper deposited along the inside of the TGV walls on and in the surface polymer film. 4 defective TGV VIAs of a total of 396 Vias were observed corresponding to a defectivity of 1%.

[0318] Fig. 17 shows a FIB SEM image of the TGV substrate with surface polymer film after electroless copper deposition. The dark areas are the VIAs (100 micron VIAs, BF33 glass with a thickness of 400 pm). In average, the surface polymer film had a thickness of approximately 100 nm throughout the VIAs and the Eless copper had a thickness of approximately 0.3 pm.

[0319] Fig. 18. Fig. 19, Fig. 20, Fig. 21 and Fig. 22 show zooms of selection 1, 2, 3, 4 and 5, respectively of Fig. 17. The thicknesses of the PHEMA surface polymer (white arrow) and the Eless copper (black arrow) are shown in each case. Having regard to standard deviations, the surface polymer film as well as the layer of Eless copper are very homogeneous and even, throughout the via structure with high conformality and good step coverage. Furthermore, the Eless copper appeared to be deposited within and on the surface polymer film. Thus, it was demonstrated that it is possible to propagate surface polymers from polymerization initiators within the VIAs and further that it was possible to deposit Eless copper throughout the VIA with very low defectivity.

[0320] Example 18

[0321] Deposition of electroless copper on TGV substrate with PHEMA-BiBB-PHEMA surface polymers

[0322] For this experiment, a TGV substrate (through-glass via, Schott BF33 1 cm x 1 cm and with a thickness of 0.45) mm was used. The substrate had a total of 4 die sets, 2 with 100 micron VIAs (pitch 300 pm and 150 pm, respectively) and 2 with 50 micron VIAs (pitch 300 pm and 150 pm, respectively).

[0323] The TGV substrate was pre-cleaned as described in Glass Pre-cleaning Procedure 2 and polymerization initiators were attached as described in Example 17. PHEMA surface polymers were formed on the TGV substrate as described in Example 17.

[0324] Subsequently second polymerization initiators (BiBB) were attached to the hydroxyl groups of the PHEMA surface polymer. First 1000 mL DMF was added to a reaction container and sonicated for 5 minutes. The TGV substrate was then submerged in the DMF for 5 minutes. DMF (931 mL), tri ethylamine (7.3 mL), and DMAP (611.8 mg) were added to Container A and the solution was sonicated until DMAP had dissolved. BiBB (62 mL) was added to the solution and mixed well to obtain the reaction mixture for functionalizing the PHEMA surface polymer with BiBB second polymerization initiators. This reaction mixture was poured into Container B, the TGV substrate was retrieved from the DMF and was immersed into the reaction mixture in Container B. Container B, containing reaction composition and TGV substrate were sonicated for 1 minute, and the substrate subsequently left for 9 minutes to form second polymer molecules from the BiBB polymerization initiators. After the reaction the substrate was retrieved from Container B and dipped 5 times in DCM (1000 mL, sonicated for 5 minutes prior to substrate dipping), and then rocked back and forth. Subsequently the substrate was sonicated in DCM for 1 minute. The substrate was retrieved from the DCM and submerged in acetone (1000 mL, sonicated for 5 minutes prior to substrate dipping), and rocked back and forth before sonicating in acetone for 5 minutes. The TGV substrate was then immersed in acetone for 7.5 minutes and then immersed in DI water for 15 minutes. Formation of surface polvmers from the PHEMA-BiBB surface polvmers on the TGV substrate. The reaction composition for this PHEMA surface polymer reaction was prepared as described in Example 4, with a polymerization time of 1 minute with sonication and 9 minutes without sonication, for a total reaction time of 10 minutes.

[0325] Electroless

[0326] The TGV substrate was processed as described in Example 14 with a sensitization step of 5 minutes and a reduction step of 3 minutes, yielding electroless deposition of copper on the surface and in the via structure of the TGV substrate.

[0327] Fig. 23, Fig. 24, and Fig. 25 show FIB SEM images of the TGV substrate (50 pm via, 150 pm pitch) with the PHEMA-BiBB-PHEMA surface polymer film and with an electroless copper layer deposited. Fig. 23 shows the upper part of the TGV substrate, Fig. 24 the middle part, and Fig. 25 the lower part of the TGV substrate. The dark parts are the vias (50 pm via, 150 pm pitch). On the sidewalls of the TGV glass part, the copper layer is visible as a narrow bright line that follows the surface of the glass part of the TGV substrate, spaced from the TGV walls substrate by the PHEMA-BiBB-PHEMA surface polymer film, which appears as darker region between the TGV substrate and the copper layer. The inventors are encouraged by the apparent coherence and uniformity of the surface polymer and the deposited copper.

[0328] The zoom in of the TGV substrate in Fig. 26 shows the top part of the TGV substrate, where the surface polymer PHEMA-BiBB-PHEMA has supported formation of a coherent copper layer. Fig. 27 and Fig. 28 show the middle and bottom parts of the TGV substrate respectively, with surface polymer PHEMA-BiBB-PHEMA film and copper layer, and demonstrates that the thickness of the surface polymer film and copper layer is quite homogeneous and coherent throughout the TGV substrate. The thickness of the copper layer at the top of the TGV substrate (Black arrows, Figure 26) was estimated to be 442.5 to 496.4 nm, and the surface polymer was measured to be 938.9 and 992.8 nm (white arrows, Fig. 26). Similarly, in the middle of the TGV substrate (Fig. 27) the thickness of the copper layer (Black arrows Fig. 27) was measured to have thickness of 539 nm and 484 nm, while the surface polymer film thickness was measured to be around 1039 and 865 nm (white arrows, Fig. 27). At the bottom of the TGV substrate the copper layer had a thickness of 464.9 and 625.9 nm (Black arrows. Fig. 27), while the surface polymer film had a have thickness of 841.7 and 593.5 nm (White arrows in Fig. 27). The thickness of both copper and surface polymer were quite similar throughout the VIA, and impressively, no or very few defects were visible in the interface between the copper layer and PHEMA-BiBB-PHEMA surface polymer film, indicating the formation of a strong and homogeneous interface between the surface polymer film and the copper layer. Thus, the PHEMA-BiBB-PHEMA surface polymer film promoted electroless deposition of a well-adhered copper layer in TGV substrates with good step coverage and high homogeneity. The inventors envision the further processing of such TGV substrates will be possible due to the well-deposited copper layer.

Claims

Claims1. A device structure comprising a surface polymer film formed on a substrate, the surface polymer film comprising polymer molecules covalently bonded to polymerization initiation sites on the substrate, and at least one first metal deposited on and within the surface polymer film.

2. A device structure according to claim 1, further comprising a second metal deposited on and within the surface polymer film.

3. A device structure according to claim 1 and 2, further comprising a metal layer formed on the surface polymer film by an electroless deposition process, the metal layer comprising the second metal, wherein the at least one first metal catalyzes the electroless deposition of the second metal.

4. A device structure according to claim 3, wherein the at least one first metal catalyzes the electroless deposition of the second metal upon activation of the at least one first metal.

5. A device structure comprising a surface polymer film formed on a substrate, the surface polymer film comprising polymer molecules covalently bonded to polymerization initiation sites on the substrate, at least one first metal, and a second metal.

6. A device structure according to claim 5, further comprising a metal layer formed on the surface polymer film by an electroless deposition process, the metal layer comprising the second metal, wherein the at least one first metal catalyzes the electroless deposition of the second metal.

7. A device structure according to claim 6, wherein the at least one first metal catalyzes the electroless deposition of the second metal upon activation of the at least one first metal.

8. A device structure according to any one of claims 1 -4 or 5-7, wherein the at least one first metal is palladium (Pd).

9. A device structure according to any one of claims 1 -4 or 5-7, wherein the second metal is copper (Cu).

10. A device structure according to claim 1 or 5. wherein the substrate comprises glass, silicon, a dielectric material, a ceramic, a composite material, metal, or a polymer.

11. A device structure according to claim 1 or 5, wherein the surface polymer film has a thickness in the range of from 100 nm to 8 pm.

12. A device structure according to claim 1 or 5, wherein the surface polymer film is formed on at least a surface of the substrate by providing the substrate, exposing the substrate to a polymerization initiator to obtain polymerization initiator sites on the substrate, and exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand. an activator, and optionally a solvent.

13. A device structure according to claim 12, wherein the catalyst of the reaction composition is obtained from Cu, Fe or Ru.

14. A device structure according to claim 12, wherein the ligand of the reaction composition is selected from N,N,N',N ",N "’-pentamethyldiethylene-triamine (PMDETA), tris[2-(dimethyl- amino)ethyl]amine (MeeTREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TPMA), 1,1, 4, 7, 10, 10-hexamethyltri ethylenetetramine (HMTETA), tetramethylethylenediamine (TMEDA), l,4,8,l l-tetramethyl-l,4,8,l l-tetraazacyclotetradecane (Me4Cyclam), and / or 2.2' -bipyridyl (BiPy).

15. A device structure according to claim 12, wherein the activator of the reaction composition is selected from sodium ascorbate (NaAsc), ascorbic acid (Asc), hydrazine, hydrazine hydrate,sodium thiosulfate, sodium sulfite, sodium dithionite, glucose, glucose with GOx, and / or pyrogallic acid.

16. A device structure according to claim 12, wherein the reaction composition further comprises a buffer.

17. A device structure according to claim 12, wherein the reaction composition further comprises a halogen salt.

18. A device structure according to claim 12, wherein the reaction composition further comprises a surfactant.

19. A device structure according to claim 12, wherein the reaction composition further comprises a polyquatemium compound.

20. A device structure according to any one of claims 12-19, wherein the polymerization initiator is selected from / i-(chloromethyl)phenyltrimethoxy silane (CPTMS), 2-bromoisobutyryl bromide (BiBB), and chloromethyl (CM) moiety.

21. A device structure according to any one of claims 1-20, wherein the surface polymer film comprises polymer molecules of poly(2-hydroxyethyl methacrylate) (PHEMA), poly(glycidyl methacrylate) (PGMA). poly(n-butyl methacrylate) (PBuMA). poly(tert-butyl methacrylate) (PtBMA), poly(benzyl methacrylate) (PBnzMA), poly(2-ethylhexyl methacrylate) (PEHMA), poly(2-hydroxy ethyl acrylate) (PHEA), and polystyrene (PSt), or a combination thereof.

22. A method for preparing a device structure according to claim 1 or claim 5, the method comprising providing a substrate having a surface polymer film comprising polymer molecules on at least a surface of the substrate, and exposing the substrate to at least one solution of a first metal to deposit the first metal on and within the surface polymer film.

23. A method of claim 22, further comprisingexposing the substrate to a solution of a second metal to deposit the second metal on and within the surface polymer film.

24. A method according to claim 22 and 23, further comprising depositing, by an electroless deposition process, a metal layer comprising the second metal, wherein the at least one first metal catalyzes the electroless deposition of the second metal, and thermally annealing the device structure.

25. A method according to claim 24, wherein the at least one first metal catalyzes the electroless deposition of the second metal upon activation of the at least one first metal26. A method for preparing a device structure according to claims 1-4 or 5-7, the method comprising providing a substrate having a surface polymer film comprising polymer molecules on at least a surface of the substrate, exposing the substrate to at least one solution of a first metal to deposit the first metal on and within the surface polymer film. exposing the substrate to a solution of a second metal to deposit the second metal on and within the surface polymer film, depositing, by an electroless deposition process, a metal layer comprising the second metal, wherein the at least one first metal catalyzes the electroless deposition of the second metal, and thermally annealing the device structure.

27. A method according to claim 26, wherein the first metal catalyzes the electroless deposition of the second metal upon activation of the at least one first metal.

28. A method according to any one of claims 22-24, wherein the first metal is palladium (Pd).

29. A method according to claim 28, wherein the at first metal is provided in the solution of the first metal as Na2PdCk30. A method according to claim 23, wherein the second metal is copper (Cu).

31. A method according to claim 30, wherein the second metal is provided in the solution of the second metal as CuSC .

32. A method according to any one of claims 22-31, wherein the substrate comprises glass, silicon, a dielectric material, a ceramic, a composite material, or a polymer.

33. A method according to claim 22 or 26, wherein the surface polymer film has a thickness in the range of from 100 nm to 8 pm.

34. A method according to claim 22 or 26, wherein the surface polymer film is formed on at least a surface of the substrate by providing the substrate, exposing the substrate to a polymerization initiator to obtain polymerization initiator sites on the substrate, and exposing the substrate to a reaction composition comprising a monomer, a catalyst, a ligand. an activator, and optionally a solvent.

35. A method according to claim 34. wherein the catalyst of the reaction composition is obtained from Cu, Fe or Ru.

36. A method according to claim 34, wherein the ligand of the reaction composition is selected from N. N, N', A ". A '-pentamethyldiethylene-triamine (PMDETA), tris[2-(dimethylamino)ethyl]- amine (MeeTREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TPMA), 1 , 1 ,4,7,10, 10-hexamethyltri ethylenetetramine (HMTETA), tetramethylethylenediamine(TMEDA), l,4,8,l l-tetramethyl-l,4,8,l l-tetraazacyclotetradecane (Me4Cyclam), and / or 2,2’- bipyridyl (BiPy).

37. A method according to claim 34, wherein the activator of the reaction composition is selected from sodium ascorbate (NaAsc), ascorbic acid (Asc), hydrazine, hydrazine hydrate, sodium thiosulfate, sodium sulfite, sodium dithionite, glucose, glucose with GOx, and / or pyrogallic acid.

38. A method according to claim 34, wherein the reaction composition further comprises a buffer.

39. A method according to claim 34, wherein the reaction composition further comprises a halogen salt.

40. A method according to claim 34, wherein the reaction composition further comprises a surfactant.

41. A method according to claim 34, wherein the reaction composition further comprises a polyquatemium compound.

42. A method according to claim 34. wherein the polymerization initiator is selected from / ?- (chloromethyl)phenyltrimethoxy silane (CPTMS), 2-bromoisobutyryl bromide (BiBB), and chloromethyl (CM) moiety.

43. A method according to claim 22, wherein the surface polymer film comprises polymer molecules of poly(2-hydroxyethyl methacrylate) (PHEMA). poly(glycidyl methacrylate) (PGMA), poly(n-butyl methacrylate) (PBuMA), poly(tert-butyl methacrylate) (PtBMA), poly(benzyl methacrylate) (PBnzMA), poly(2-ethylhexyl methacrylate) (PEHMA), poly(2- hydroxyethyl acrylate) (PHEA), and polystyrene (PSt), or a combination thereof.

44. A system for forming a device structure according to claims 1-4 or 5-7 comprising a first container containing a reaction composition for forming a surface polymer film from polymerization initiator sites on at least a portion of a surface of a substrate, at least one second container containing a solution of a first metal for depositing the first metal on and within the surface polymer film, at least one third container containing a solution for reducing the first metal deposited on and within the surface polymer film, at least one fourth container containing a solution for activating the first metal deposited on and within the surface polymer film. a fifth container containing an electroless solution of a second metal for depositing, by an electroless procedure, the second metal on and within the surface polymer film, and a substrate displacement device,wherein the substrate displacement device brings at least a portion of the substrate with polymerization initiator sites into contact with the reaction composition in the first container for a first controlled time, wherein the first controlled time is sufficient for forming the surface polymer film from the polymerization initiator sites, and wherein the substrate displacement device brings at least a portion of the substrate with surface polymer film into contact with the solution in the at least one second container for a second controlled time, wherein the second controlled time is sufficient for depositing the first metal on and within the surface polymer film, wherein the substrate displacement device brings at least a portion of the substrate with surface polymer film and first metal into contact with the solution in the at least one third container for a third controlled time, wherein the third controlled time is sufficient for reducing the first metal in and within the surface polymer film, wherein the substrate displacement device brings at least a portion of the substrate with surface polymer film and first metal into contact with the solution in the at least one fourth container for a fourth controlled time, wherein the fourth controlled time is sufficient for activating the first metal deposited on and within the surface polymer film, and wherein the substrate displacement device brings at least a portion of the substrate with surface polymer film and first metal into contact with the solution in the fifth container for a fifth controlled time, wherein the fifth controlled time is sufficient for depositing, by an electroless deposition process, a second metal on and within the surface polymer film.

45. A system according to claim 44, comprising one or more additional containers for rinsing the substrate.

46. A system according to claim 44 or 45. comprising a further container containing a polymerization initiator for forming polymerization initiator sites on at least portion of a surface of the substrate.

47. A system according to claim 44, comprising a further container containing a cross-linking agent for cross-linking the polymer molecules of the surface polymer film, wherein the substrate displacement device brings at least a portion of the substrate with surface polymer film into contact with the cross-linking agent in the further container for a further controlled time, whereinthe further controlled time is sufficient to cross-link the polymer molecules in the surface polymer film.

48. A system according to claim 47, wherein the cross-linking of the polymer molecules of the surface polymer film is before depositing of the first metal, or after depositing of the first metal.

49. A system according to claim 44, further comprising an oven for thermally annealing the device structure.

50. A system according to claim 44, wherein the first metal is palladium (Pd), and the second metal is copper (Cu).

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