Dielectric copolymer material

Abstract

The present invention relates to a polymerizable mixture which can be used to form a dielectric material for preparing a passivation layer in an electronic device. The polymerizable mixture comprises a first monomer and a second monomer which can react to form a copolymer having excellent film-forming ability, excellent thermal properties and excellent mechanical properties. A method of forming the copolymer and an electronic device comprising the copolymer as a dielectric material are also provided. In addition, the present invention relates to a manufacturing method for preparing a packaged microelectronic structure and to a microelectronic device comprising the packaged microelectronic structure formed by the manufacturing method.

Description

Field of the Invention

[0001] The present invention relates to a new type of copolymer which can be used as a dielectric material for preparing a passivation layer in encapsulated electronic devices. The copolymer is obtained from a polymerizable mixture comprising a first monomer and a second monomer, wherein the first monomer is one or more polymerizable maleimide compounds having a mesogenic group, and wherein the second monomer is one or more difunctional or polyfunctional compounds capable of reacting with the first monomer to obtain a copolymer. The first monomer may also be referred to as reactive mesogen (RM). Thus, the copolymers obtained therefrom are materials having liquid crystal properties in their structure, and they provide excellent film-forming ability, excellent thermal properties, excellent mechanical properties, and the property of being easily processed from conventional solvents. In particular, the copolymers are characterized by a low dielectric constant and thermomechanical properties which reduce the thermally induced stress due to the mismatch in the coefficient of thermal expansion (CTE) between substrates and packages dominated by silicon (3 ppm / K) and copper (16.5 ppm / K). In addition, the copolymers provide a favorable and well-balanced relationship between rigidity and elasticity, so that the thermal stress can be easily compensated. Moreover, they are photo-structurable and are particularly suitable for various applications in electronic packaging, such as passivation of conductive or semiconductor components and chip bonding, and as a main component in the preparation of printed circuit board substrates.

[0002] Also provided are a method of forming the copolymer and an electronic device comprising the copolymer as a dielectric material. In addition, the present invention relates to a manufacturing method for preparing an encapsulated microelectronic structure, wherein a dielectric copolymer layer is formed from the polymerizable mixture, and to a microelectronic device comprising an encapsulated microelectronic structure obtained or obtainable by the manufacturing method.

[0003] The manufacturing method according to the present invention allows for cost-effective and reliable manufacturing of microelectronic devices, wherein the number of defective products caused by mechanical deformation (warpage) due to undesirable thermal expansion is significantly reduced. Polymerization and / or curing can occur at significantly lower temperatures, resulting in lower thermal stress during the manufacturing process, which reduces the waste of defective microelectronic devices, thereby allowing resource conservation and sustainable production. Background of the Invention

[0005] When reactive mesogens (RMs) are polymerized at a temperature at which they exhibit a thermotropic liquid crystal (LC) phase (usually a nematic, cholesteric or smectic phase), anisotropic polymers that retain the liquid crystal state are obtained. In particular, optical anisotropy has been widely used in the field of optical films to compensate for and enhance brightness in flat panel displays, especially liquid crystal displays.

[0006] In addition to their widespread use in liquid crystal displays and monitors, the advantages of liquid crystal materials in other types of applications due to their special physical properties have also been studied (R. Stannarius, Nat. Mat. 2009, 8, 617 - 618; and J. P. F. Lagerwall et al., Current Appl. Phys. 2012, 12, 1387 - 1412). In particular, highly ordered anisotropic polymer networks are an interesting class of materials with a wide range of applications (D. J. Broer et al., Lagmuir 2014, 30, 13499 - 13509; and R. Zentel et al., Adv. Mater. 2010, 22, 3366 - 3387). However, in most cases, LC polymers or the monomers from which the corresponding polymers are prepared do not have the optimal properties required for the respective applications.

[0007] WO 2012 / 152409 A1 relates to polymer particles having optical anisotropy and shape anisotropy comprising at least one reactive mesogenic monomer unit, methods for their preparation, the use of these particles in the preparation of optical, electro - optical, electronic, electrochemical, electrophotographic, electrowetting and electrophoretic displays and / or devices as well as in security, beauty, decorative and diagnostic applications, and an electrophoretic fluid and a display comprising said polymer particles. In particular, the polymer particles have at least one RM monomer unit having at least two polymerizable groups, at least one polymerizable dye as a comonomer, optionally at least one comonomer, optionally at least one cross - linking comonomer, optionally at least one ionic comonomer, and optionally at least one polymerizable stabilizer.

[0008] Various methods for preparing liquid crystal polymers from RM and for preparing RM starting materials are known from the prior art. For example, Siemensmeyer et al. described a method for preparing a mixture of LC compounds, wherein at least one starting component consists of a mixture of at least two compounds, and this mixture reacts with at least one other starting component to form a statistical mixture (WO96 / 04351A1).

[0009] In addition to effective preparation methods for LC compounds, suitable polymerization methods for forming anisotropic polymer networks are also a focus of attention. The applicability of various reactive functional groups in photo - initiated polymerization reactions has been studied. The most widespread reactive functional groups are acrylate groups and methacrylate groups, which are particularly suitable for UV - induced radical polymerization reactions due to their high polymerization rates (D. J. Broer et al., Lagmuir 2014, 30, 13499 - 13509). However, UV curing is not suitable for all types of applications.

[0010] Mixtures of polymerizable liquid crystal monomers (reactive mesogens) can be used to prepare films that can be cured by polymerization reactions initiated by heat or light. The films prepared in this way are relatively thin and contain highly crosslinked thermoplastic polymers with marked dimensional stability. However, these films are rather brittle and exhibit very low elasticity. On the other hand, if the degree of crosslinking is reduced, dimensionally stable polymer films cannot be obtained.

[0011] US 6,261,481 B1 describes an organic insulating composition providing good thermal conductivity. The insulating composition contains a liquid crystal (LC) resin, which is a polymerization product of a resin composition containing monomers having a mesogenic group. The composition has a thermal conductivity of ≥0.4 W / mK in directions orthogonal to each other. The monomers contained in the resin composition have a mesogenic group and preferably have an epoxy group that can be thermally polymerized under acid catalysis. Preferably, at the start of polymerization, the resin composition is heated under conditions where the monomers having a mesogenic group are partially aligned so that the anisotropic properties based on the partial alignment are frozen in the polymer.

[0012] US 2008 / 0075961 A1 and US 2017 / 0152418 A1 relate to maleimide adhesive films prepared from thermosetting maleimide resins of imide-extended mono-, bis- and polymaleimide compounds. The maleimide adhesive films are photo-structurable and suitable for the production of electronic devices, integrated circuits, semiconductor devices, passive devices, solar cells, solar modules and / or light-emitting diodes. However, the maleimide compounds do not contain any mesogenic groups that can impart a preferred orientation or partial alignment to the compounds in the film. This results in poor performance in terms of mechanical stability and thermal conductivity. These materials also generally exhibit a relatively low glass transition temperature, which again affects their thermal expansion properties.

[0013] KR20160052234A describes a photocurable insulating resin composition and a printed circuit board using the composition. The photocurable insulating resin composition contains a photocurable liquid crystal oligomer; a photocurable graphene oxide; and a photocurable metal alkoxide. However, the photocurable liquid crystal oligomer does not contain a plurality of mesogenic groups linked together by a spacer group. This results in an unfavorable dissolution profile and a very high energy requirement for photocuring.

[0014] Electronic packaging

[0015] As solid-state transistors began to replace vacuum tube technology, electronic components such as resistors, capacitors, and diodes could be directly mounted onto the printed circuit board of the card through their leads, thus establishing the basic building blocks or package levels still in use today. Complex electronic functions typically require more individual components than can be interconnected on a single printed circuit card. The ability to have multi-layer cards was accompanied by the development of three-dimensional packaging of daughter cards on multi-layer motherboards. Integrated circuits allowed many discrete circuit elements (such as resistors and diodes) to be embedded into a single relatively small component called an integrated circuit chip (chip) or die. However, despite incredible circuit integration, more than one package level was often required, partly due to the technology of the integrated circuit itself. Integrated circuit chips are very fragile and have extremely small terminals. The first-level package serves the primary functions of providing mechanical protection, cooling, and the ability to make electrical connections to the delicate integrated circuit. Since some components (high-power resistors, mechanical switches, capacitors) are not easily integrated onto the chip, at least one additional package level, such as a printed circuit card, is used. For very complex applications (such as mainframe computers), a hierarchy of multiple package levels is required.

[0016] Due to Moore's Law, advanced electronic packaging strategies play an increasingly important role in the development of more powerful electronic products. In other words, as the demand for smaller, faster, and more functional mobile and portable electronic devices increases, the demand for improved cost-effective packaging technologies also increases.

[0017] To meet the demands of today's semiconductor industry, a wide variety of advanced packaging technologies exist. Leading advanced packaging technologies - wafer-level packaging (WLP), fan-out wafer-level packaging (FOWLP), 2.5D interposers, chip stacking, package stacking, embedded ICs - all require structured thin substrates, redistribution layers, and other components such as high-resolution interconnects. The end-user market continuously drives lower prices and higher functionality for smaller and thinner devices. This drives the need for next-generation packages with more refined features and improved reliability at competitive manufacturing costs.

[0018] Wafer-level packaging (WLP) is a technology for packaging integrated circuits while they are still part of a wafer, as opposed to more conventional chip-level packaging methods where the wafer is cut into individual circuits (die) and then packaged. Compared to chip-level packaging technology, WLP has several major advantages, and it is actually a true chip-scale packaging (CSP) technology because the resulting package is actually the same size as the chip. Wafer-level packaging allows for the integration of wafer manufacturing, packaging, testing, and burn-in at the wafer level to simplify the manufacturing process that the device undergoes from silicon to customer shipment. Due to size limitations, the main application areas of WLP are smartphones and wearable devices. The functions provided by WLP in smartphones or wearable devices include: compass, sensors, power management, wireless, etc. Wafer-level chip-scale packaging (WL-CSP) is one of the smallest packages available on the market currently. WLP can be divided into fan-in and fan-out WLP( Figure 1 ). They both use redistribution technology to form the connection between the chip and the solder balls.

[0019] Fan-out wafer-level packaging (FOWLP) is one of the latest packaging trends in the microelectronics field: FOWLP has a high potential for miniaturization both in terms of packaging volume and packaging thickness. The technical basis of FOWLP is a reconfigured sputtered wafer with embedded chips and thin-film redistribution layers, which together form a package compatible with surface-mount devices (SMD). The main advantages of FOWLP are being very thin due to substrate-less packaging, low thermal resistance, and good high-frequency characteristics, which are attributed to short and planar electrical connections and bump-less chip connections, rather than, for example, soldering or solder contacts.

[0020] In the case of current materials, the WLP process is limited to applications with medium chip sizes. The reasons for this limitation are mainly due to the current material selection, which shows a thermal mismatch with silicon chips (CTE: 3 ppm / K), and thus will reduce performance and generate stress on the chip. There is a great demand for new materials with better physical properties (especially a coefficient of thermal expansion (CTE) closer to that of silicon and high mechanical flexibility). Currently, the redistribution layer (RDL) is made of copper layers (CTE: 16.5 ppm / K), which are electroplated on polymer passivation layers such as polyimide (PI), benzocyclobutene (BCB), or polybenzoxazole (PBO). In addition to being photo-patternable, low curing temperature is another two important requirements in the processing of such materials. Polyimide has become the standard passivation layer for memory chips and other devices that require surface protection during processing and testing procedures. Photosensitive resins have been developed to reduce processing costs.

[0021] Polyimide has become the standard passivation layer for memory chips and other devices that require surface protection during processing and testing procedures. Photosensitive resins have been developed to reduce processing costs.

[0022] Polyimide-ODA is the first member of a new series of high-performance polymers based on alternating aromatic homocycles and heterocycles developed by DuPont:

[0023]

[0024] Polyimides are very unique due to their very high decomposition temperature (up to over 400 °C). In addition, their mechanical properties ensure high flexibility (elongation at break up to 100%), and they have a very high tensile strength of over 200 MPa. PI remains the most popular polymer for IC passivation.

[0025] Modification of negative-sensitive polymer PI is achieved through polybenz oxazole (PBO) (sometimes also called positive-sensitive PI):

[0026]

[0027] Polymer films can be developed using an aqueous developer after exposure.

[0028] The so-called BCB (benzocyclobutene) is an example of a siloxane polymer group that also has vinyl and benzocyclobutene ring systems:

[0029]

[0030] The main advantage is a polymerization reaction with high atom economy (Diels-Alder reaction) because no by-products appear. This highly cross-linked thermosetting polymer has excellent electrical properties but is very brittle, with a low elongation at break value (8%) and a low tensile strength of 87 MPa.

[0031] Another method from the prior art is the imide-extended bismaleimide resin proposed in US 2008 / 0075961 A1 and US 2017 / 0152418 A1. They show encouraging results in low-stress wafer passivation coatings. However, despite the improvements, there is still room for improvement to meet the demanding requirements of the industry.

[0032] In summary, the materials known from the prior art have the following disadvantages:

[0033] · Polyimides and polybenz oxazoles usually require very high processing temperatures, which increases the risk of warping, especially in multi-layer redistribution layers (RDLs). In addition, polyimides show high water absorption, which is a problem for device reliability.

[0034] · Benzocyclobutene derivatives and polynorbornenes exhibit very low dielectric constants, but their poor adhesion to metals undermines this advantage.

[0035] · To date, imide-extended bismaleimide resins have not shown a suitable combination of favorable mechanical and thermal properties. They are either flexible (low modulus) but have high CTE values, or brittle (high modulus) with low CTE values.

[0036] Accordingly, there is a continuing need to develop novel dielectric materials that do not exhibit the above-mentioned drawbacks known in the prior art.

[0037] Lithography technology

[0038] For a long time, lithography has been the key patterning technology for structuring inorganic and organic materials used in advanced packaging applications such as flip-chip wafer bumping, electroplated gold, solder bumping, copper pillar technology, and redistribution layers. Lithography is a critical manufacturing process and cost contributor. In today's industrial lithography applications, carefully selecting the correct exposure scheme is crucial for achieving the best cost structure.

[0039] Current drivers and trends in the semiconductor industry clearly indicate the need to improve the performance of microelectronic devices to meet future end-user requirements. For example, consumer electronic devices such as tablets and smartphones are becoming thinner and smaller while gaining higher computing power, more data storage, and improved communication capabilities. Additionally, cost considerations are becoming increasingly important in the competitive landscape for all parties in the supply chain, from chip manufacturers, foundries, assembly and test suppliers to device manufacturers. Therefore, the industry endeavors to seek innovative ways to reduce manufacturing costs while achieving technologies that meet challenging technical requirements.

[0040] For decades, lithography has been and remains the fundamental process used in the fabrication and packaging of microelectronic devices. A key component of any lithography process is the exposure tool, which uses light in the ultraviolet wavelength range to pattern a photosensitive resist or polymer. The exposure tool must be able to precisely generate the desired features and align them with previously fabricated structures in the underlying layer. Currently, there are several types of exposure techniques: proximity or contact printing, laser direct imaging, and projection lithography. The corresponding equipment tool sets differ in terms of technical capabilities (optical resolution, overlay performance, and effective throughput) as well as the costs associated with the exposure process. (See H. Hichri et al., Micro Tec Photonic System Inc., Corona, CA, USA).

[0041] Object of the invention

[0042] The object of the present invention is to overcome the deficiencies and drawbacks in the prior art and to provide novel materials that can be used as diverse dielectric materials in various electronic packaging applications.

[0043] In addition, an object of the present invention is to provide novel dielectric materials that, when used to form a passivation layer in a packaged electronic device, exhibit excellent film-forming ability, excellent thermal properties such as a low coefficient of thermal expansion (CTE), and excellent mechanical properties such as excellent flexibility. Another object of the present invention is to provide novel dielectric materials that allow for easy processing from conventional solvents.

[0044] More specifically, an object of the present invention is to match the coefficient of thermal expansion of the dielectric with that of, for example, silicon (Si: 3 ppm / K) or copper (Cu: 16.5 ppm / K) without adversely affecting mechanical properties such as the elongation at break after UV or thermal curing at temperatures below 200 °C.

[0045] In addition, an object of the present invention is to provide novel materials that are photo-structurable and are particularly suitable for various applications in electronic packaging, such as passivation of conductive or semiconductor components and chip bonding, and as a main component in the preparation of printed circuit board substrates. An important field of application is as a structured dielectric material for RDLs in packaged microelectronic devices.

[0046] Another object of the present invention is to provide a polymerizable mixture from which the novel materials are made. In addition to this, an object of the present invention is to provide a method for forming the novel materials using the polymerizable mixture. Finally, an object of the present invention is to provide electronic devices including the novel materials as dielectric materials, a manufacturing method for preparing packaged microelectronic structures, and microelectronic devices including the packaged microelectronic structures obtainable by the manufacturing method. Summary of the Invention

[0047] The inventors have surprisingly found that the above objects are achieved by a copolymer obtained from a polymerizable mixture comprising a first monomer and a second monomer, wherein the first monomer is one or more compounds represented by formula (1), and wherein the second monomer is one or more difunctional or polyfunctional compounds capable of reacting with the first monomer to form a copolymer:

[0048] P 1 -Sp 1 -(MG-Sp 1 ) m -P 1 Formula (1)

[0049] Wherein:

[0050] m is an integer from 1 to 60;

[0051] P 1 represents

[0052] Sp 1 represents a spacer group (Sp) or a single bond each time it appears;

[0053] MG is a rod-like mesogenic group, which is preferably selected from formula (2):

[0054] -(A 21 -Z 21 ) k -A 22 -(Z 22 -A 23 ) l - formula (2)

[0055] wherein:

[0056] A 21 to A 23 are independently and each time they appear independently of each other aryl, heteroaryl, heterocyclic, cycloaliphatic or cyclic imide group, optionally substituted by one or more identical or different groups L;

[0057] Z 21 and Z 22 are independently and each time they appear independently of each other -O-, -S-, -CO-, -COO-, -OCO-, -S-CO-, -CO-S-, -O-COO-, -CO-NR 01 -, -NR 01 -CO-, -NR 01 -CO-NR 02 -, -NR 01 -CO-O-, -O-CO-NR 01 -, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CH2CH2-, -(CH2)4-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR 01 -, -CY 01 =CY 02 -, -C≡C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond;

[0058] R 01 and R 02 each independently of one another represent H or an alkyl group having 1 to 12 C atoms;

[0059] L is F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)NR xx R yy 、-C(=O)OR xx 、-C(=O)R xx 、-NR xx R yy 、-OH, -SF5 or a straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 20 C atoms, where one or more H atoms are optionally replaced by F or Cl, -CN or a straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 6 C atoms;

[0060] R xx and R yy each independently represent H or an alkyl group having 1 to 12 C atoms;

[0061] Y 01 and Y 02 each independently represent H, an alkyl group having 1 to 12 C atoms, an aryl group, F, Cl or CN; and

[0062] k and l are each independently 0, 1, 2, 3 or 4.

[0063] The polymerizable mixture is used as a starting material to form a novel copolymer that exhibits low thermal expansion and at the same time exhibits high mechanical flexibility. The copolymer is prepared by a method that also forms part of the present invention:

[0064] A method for forming a copolymer, wherein the method comprises the steps of:

[0065] (i) providing a polymerizable mixture according to the present invention; and

[0066] (ii) polymerizing the polymerizable mixture to obtain a copolymer.

[0067] Furthermore, a copolymer obtainable or obtained by the above-described method for forming a copolymer is provided.

[0068] In addition, an electronic device comprising a copolymer according to the present invention is provided.

[0069] Finally, a manufacturing method for preparing a packaged microelectronic structure is provided, wherein a dielectric layer is provided on a substrate, and the method comprises the steps of:

[0070] (1) applying a polymerizable mixture according to the present invention to the surface of the substrate; and

[0071] (2) Polymerize the polymerizable composition to form a dielectric layer.

[0072] Also provided is a microelectronic device comprising a packaged microelectronic structure obtainable or obtained by a manufacturing method according to the invention.

[0073] Preferred embodiments of the invention are described below and in the dependent claims.

[0074] Brief Description of the Drawings

[0075] Figure 1 : Cross-sectional view of a fan-out and fan-in WLP having a chip (1) and a fan-out region (2).

[0076] Detailed Description

[0077] Definitions

[0078] The terms "liquid crystal", "mesogenic compound" or "mesogenic compound" (also abbreviated as "mesogen") refer to compounds that can exist as a mesophase, or in particular as an LC phase, under suitable temperature, pressure and concentration conditions. Non-amphiphilic mesogenic compounds include, for example, one or more rod-like, banana-shaped or disc-shaped mesogenic groups.

[0079] The term "rod-like" refers to a compound or group that is rod-shaped or plate-shaped / platelet-shaped. The term "banana-shaped" refers to a bent group in which two generally rod-like mesogenic groups are connected by a semi-rigid group in a non-collinear manner. The term "disc-shaped" refers to a compound or group that is disc-shaped or sheet-shaped.

[0080] The term "mesogenic group" or its abbreviation "MG" refers to a group having the ability to induce liquid crystal (LC) phase behavior. Mesogenic groups, especially those of the non-amphiphilic type, are usually rod-shaped or disc-shaped. Compounds containing mesogenic groups do not necessarily have to exhibit an LC phase themselves. They may also only exhibit an LC phase in a mixture with other compounds or when the mesogenic compound or its mixture is polymerized. For simplicity, the term "liquid crystal" is used hereinafter for mesogens and LC materials.

[0081] Rod-like mesogenic compounds generally comprise a rod-shaped, i.e., rod-shaped or plate-shaped / platelet-shaped, mesogenic group consisting of one or more aromatic or alicyclic groups directly or connected to each other by a linking group, optionally comprising end groups attached to the short ends of the rod, and optionally comprising one or more side groups attached to the long sides of the rod, wherein these end groups and side groups are generally selected from, for example, carbonyl or hydrocarbon groups, polar groups such as halogen, nitro, hydroxyl, etc., or polymerizable groups.

[0082] Discotic mesogenic compounds generally comprise, for example, a discotic, i.e., relatively flat disc-shaped or platelet-shaped mesogenic group consisting of one or more fused aromatic or cycloaliphatic groups, such as terphenylenes, and optionally one or more end groups attached to the mesogenic group, which are selected from the above-mentioned end groups and side groups.

[0083] The term "reactive mesogen" or its abbreviation "RM" refers to a polymerizable mesogenic or liquid crystalline compound, which is preferably a monomeric or oligomeric compound.

[0084] The term "spacer" or "spacer group", hereinafter also referred to as "Sp", is known to those skilled in the art and has been described in the literature. Unless otherwise specified, the term "spacer" or "spacer group" in the context refers to a flexible organic group that connects the mesogenic group and one or more polymerizable groups in a polymerizable mesogenic compound ("RM").

[0085] The term "polymer" includes, but is not limited to, homopolymers, copolymers such as block copolymers, random copolymers and alternating copolymers, terpolymers, quaterpolymers, etc., as well as blends and variants thereof. In addition, unless otherwise specifically defined, the term "polymer" shall include all possible configurational isomers of the material. These configurations include, but are not limited to, isotactic, syndiotactic and atactic symmetries. A polymer is a high relative molecular mass molecule whose structure essentially comprises multiple repetitions of units (i.e., repeating units) that are actually or conceptually derived from low relative mass molecules (i.e., monomers). In the context of the present invention, a polymer is composed of more than 60 monomers.

[0086] In contrast to polymers, the term "oligomer" is a molecular complex composed of several monomer units, where the number of monomers is not limited in principle. Dimers, trimers and tetramers are, for example, oligomers composed of two, three and four monomers, respectively. In the context of the present invention, an oligomer can be composed of up to 60 monomers.

[0087] As used herein, the term "monomer" refers to a polymerizable compound that can undergo polymerization to contribute structural units (repeating units) to the basic structure of a polymer or oligomer. A polymerizable compound is a functionalized compound having one or more polymerizable groups. A large number of monomers combine in a polymerization reaction to form a polymer. A monomer having one polymerizable group is also called a "monofunctional" or "monoreactive" compound, a compound having two polymerizable groups is called a "bifunctional" or "di-reactive" compound, and a compound having more than two polymerizable groups is called a "polyfunctional" or "polyreactive" compound. A compound having no polymerizable group is also called a "non-functional" or "non-reactive" compound.

[0088] As used herein, the term "homopolymer" represents a polymer derived from one (real, implied or hypothetical) monomer.

[0089] As used herein, the term "copolymer" generally refers to any polymer derived from more than one monomer, wherein the polymer contains more than one corresponding repeating unit. In one embodiment, the copolymer is the reaction product of two or more monomers and thus contains two or more corresponding repeating units. Preferably, the copolymer contains two, three, four, five or six repeating units. A copolymer obtained by copolymerizing three monomers may also be referred to as a terpolymer. A copolymer obtained by copolymerizing four monomers may also be referred to as a quaternary copolymer. Copolymers can exist as block, random, and / or alternating copolymers.

[0090] As used herein, the term "block copolymer" represents a copolymer in which adjacent blocks are structurally different, i.e., adjacent blocks contain repeating units derived from different types of monomers or contain repeating units derived from the same type of monomer but having different compositions or different sequence distributions of the repeating units.

[0091] In addition, as used herein, the term "random copolymer" refers to a polymer formed by macromolecules in which the probability of finding a given repeating unit at any given position in the chain is independent of the nature of the adjacent repeating units. Generally, in a random copolymer, the sequence distribution of the repeating units follows Bernoulli statistics.

[0092] As used herein, the term "alternating copolymer" represents a copolymer composed of macromolecules containing two repeating units in an alternating sequence.

[0093] "Electronic packaging" is a major discipline in the field of electronic engineering and encompasses a variety of technologies. It refers to the insertion of discrete components, integrated circuits, and MSI (medium-scale integration) and LSI (large-scale integration) chips (usually connected to a lead frame by beam leads) into a board through vias in a multi-layer circuit board (also known as a card), where they are soldered in place. The packaging of an electronic system must take into account protection against mechanical damage, cooling, radio frequency noise emission, protection against electrostatic discharge maintenance, operator convenience, and cost.

[0094] As used herein, the term "microelectronic device" refers to an electronic device having very small electronic designs and components. Usually but not always, this means on the micron scale or smaller. These devices typically contain one or more microelectronic components made of semiconductor materials and interconnected in a packaged structure to form a microelectronic device. Many electronic components of common electronic designs are available in microelectronic equivalents. These include transistors, capacitors, inductors, resistors, diodes, and natural insulators and conductors, all of which can be found in microelectronic devices. Due to the usually small size of the components, leads, and pads, unique wiring techniques such as wire bonding are also often used in the microelectronic field.

[0095] As used herein, "nanoparticle" refers to particles with an average diameter in the range of 1 to 100 nm. More preferably, the average diameter of the nanoparticles is in the range of 20 to 80 nm, and even more preferably in the range of 40 to 60 nm.

[0096] Preferred embodiment

[0097] Polymerizable compound

[0098] The present invention relates to a polymerizable mixture comprising a first monomer and a second monomer, wherein the first monomer is one or more compounds represented by formula (1), and wherein the second monomer is a difunctional or polyfunctional compound capable of reacting with the first monomer to form a copolymer:

[0099] P 1 -Sp 1 -(MG-Sp 1 ) m -P 1 Formula (1)

[0100] Wherein:

[0101] m is an integer from 1 to 60;

[0102] P 1 Represents

[0103] Sp 1 Each occurrence represents a spacer group (Sp) or a single bond;

[0104] MG is a rod-like mesogenic group, which is preferably selected from formula (2):

[0105] -(A 21 -Z 21 ) k -A 22 -(Z 22 -A 23 ) l - Formula (2)

[0106] Wherein:

[0107] A 21 To A 23 Independently and each occurrence independently of one another is aryl, heteroaryl, heterocyclic, cycloaliphatic or cyclic imide group, optionally substituted by one or more identical or different groups L;

[0108] Z 21 And Z 22 Independently and each occurrence independently of one another is -O-, -S-, -CO-, -COO-, -OCO-, -S-CO-, -CO-S-, -O-COO-, -CO-NR 01-, -NR 01 -CO-, -NR 01 -CO-NR 02 , -NR 01 -CO-O-, -O-CO-NR 01 -, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CH2CH2-, -(CH2)4-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR 01 -, -CY 01 =CY 02 -, -C≡C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond;

[0109] R 01 and R 02 each independently of one another represent H or an alkyl group having 1 to 12 C atoms;

[0110] L is F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)NR xx R yy , -C(=O)OR xx , -C(=O)R xx , -NR xx R yy , -OH, -SF5 or a straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 20 C atoms, where one or more H atoms are optionally replaced by F or Cl, -CN or a straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 6 C atoms;

[0111] R xx and R yy independently of one another represent H or an alkyl group having 1 to 12 C atoms;

[0112] Y 01 and Y 02 each independently of one another represent H, an alkyl group having 1 to 12 C atoms, an aryl group, F, Cl or CN; and

[0113] k and l are each independently 0, 1, 2, 3 or 4.

[0114] The point of attachment (binding site) of the structural elements present in this patent application can be indicated by where * represents the structural element and Represents a binding site.

[0115] Polymerizable group P 1 is a maleimide group, which is capable of undergoing a polymerization reaction, such as a free radical or ionic chain polymerization reaction, or an addition polymerization reaction (such as a cycloaddition, such as a 2+2 cycloaddition, a 4+2 cycloaddition (Diels-Alder reaction) or a 1,3-dipolar cycloaddition or a nucleophilic addition, such as a Michael reaction), or is capable of undergoing a reaction similar to polymerization, such as being added to a polymer backbone by one of the above reaction types.

[0116] The subscript m is preferably an integer from 1 to 50, more preferably from 2 to 30, and most preferably from 3 to 20.

[0117] Preferably, Z 21 and Z 22 are independently and each independently at each occurrence -COO-, -OCO-, -CO-O-, -O-CO-, -OCH2-, -CH2O-, -CH2CH2-, -(CH2)4-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -C≡C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond.

[0118] Preferably, k and l are each independently 0, 1 or 2, more preferably k and l are 1.

[0119] Preferably, the spacer group Sp is selected from the formula Sp'-X', such that the group "P 1 -Sp 1 -" corresponds to the formula "P 1 -Sp'-X'-", where:

[0120] Sp' represents

[0121] (a) a straight-chain or branched-chain alkylene having 1 to 40, preferably 1 to 30 C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN, and wherein, in addition, one or more non-adjacent CH2 groups can each independently be replaced by -O-, -S-, -NH-, -NR 01 -, -SiR 01 R 02 -, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -NR 01 -CO-O-, -O-CO-NR 01 -, -NR 01 -CO-NR 01 - in such a way that O and / or S atoms are not directly connected to each other, or

[0122] (b)-Sp x -G-Sp y - wherein Sp x and Sp y each independently represents an alkylene group having 1 to 20 C atoms, preferably 1 to 12 C atoms, or a single bond; G represents a cycloalkylene group having 3 to 20 C atoms, preferably 5 to 12 C atoms, which is optionally mono- or polysubstituted by an alkyl group having 1 to 20 C atoms, preferably 1 to 12 C atoms;

[0123] X' represents -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 01 -, -NR 01 -CO-, -NR 01 -CO-NR 01 -, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=C-, -N=N-, -CH=CR 01 -, -CY 01 =CY 02 -, -C≡C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond, preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 0 -, -NR 01 -CO-, -NR 01 -CO-NR 01 - or a single bond;

[0124] R 01 and R 02 each independently represent H or an alkyl group having 1 to 12 C atoms; and

[0125] Y 01 and Y 02 each independently represent H, F, Cl or CN.

[0126] Preferred groups Sp′ are in each case selected from straight-chain methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene and octadecylene, cyclohexylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethyl-N-methyliminoethylene, 1-methylalkylene, vinylidene, propenylene and butenylene.

[0127] More preferably, the spacer group Sp is selected from -(CH2) p1 -, -(CH2CH2O) q1 -CH2CH2-, -CH2CH2-S-CH2CH2-, -CH2CH2-NH-CH2CH2-, -(SiR 01 R 02 -O) p1 -, -(CH2) p1 -(cyclo-C6H8R 01 R 02 )-(CH2) p1 - and

[0128]

[0129] wherein:

[0130] p1 is an integer from 1 to 60, preferably from 1 to 36, more preferably from 1 to 12;

[0131] q1 is an integer from 1 to 12, preferably from 1 to 3; and

[0132] R 01 and R 02 each independently of one another represents H or an alkyl group having 1 to 12 C atoms.

[0133] The most preferred group Sp is -(CH2) p1 -, -O-(CH2) p1 -, -O-(CH2) p1 -O-, -OCO-(CH2) p1 - and -OCOO-(CH2) p1 -, where p1 is an integer from 1 to 36, preferably from 1 to 12.

[0134] In a preferred embodiment of the present invention, the groups A 21 to A 23 independently represent, and in the case of multiple occurrences, independently of one another represent moieties selected from the following groups a) to e):

[0135] a) trans-1,4-cyclohexylene, 1,4-cyclohexenylene and 4,4'-dicyclohexylidene, where one or more non-adjacent CH2 groups may be replaced by -O- and / or -S-, and where one or more H atoms may be replaced by the group L;

[0136] b) 1,4-phenylene, 1,3-phenylene, 4,4'-biphenylene, 2,5-thienyl and 2,6-dithieno[3,2-b:2',3'-d]thiophenyl, where one or two CH groups may be replaced by N, and one or more H atoms may be replaced by the group L;

[0137] c) Tetrahydropyran-2,5-diyl, 1,3-dialkane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, which may be substituted by one or more groups L; d) A saturated, partially unsaturated or fully unsaturated and optionally substituted polycyclic group having 5 to 20 ring C atoms, wherein one or more ring C atoms may also be replaced by heteroatoms, preferably selected from bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl,

[0138] e) wherein one or more H atoms may be replaced by group L, and / or one or more double bonds may be replaced by single bonds, and / or one or more CH groups may be replaced by N, and wherein

[0139]

[0140]

[0141] M represents -O-, -S-, -CH2-, -CHY

[0142] - or -CY 03 -; 03 Y 04 -;

[0143] Y 03 and Y 04 independently of one another represent one of the meanings given above for R 01 and are preferably H, F, Cl, CN, OCF3 or CF3;

[0144] W 5 and W 6 independently of one another represent -CH2CH2-, -CH=CH-, -CH2-O-, -O-CH2-, -C(R c R d )- or -O-;

[0145] R c and R d independently of one another represent H or an alkyl group having 1 to 6 C atoms, preferably H, methyl or ethyl; and

[0146] R 03 and R 04 independently of one another represent H, F, a straight-chain or branched-chain alkyl group having 1 to 12 C atoms, wherein one or more H atoms may be replaced by F;

[0147] e) a cyclic imido group selected from the following:

[0148]

[0149] wherein one or more H atoms may be replaced by a group L, and / or one or more double bonds may be replaced by a single bond, and / or one or more CH groups may be replaced by N.

[0150] Preferably, the first monomer contained in the polymerizable mixture according to the present invention is one, two, three or four compounds represented by formula (1).

[0151] Preferred compounds according to formula (1) are:

[0152]

[0153]

[0154]

[0155]

[0156]

[0157]

[0158] wherein the groups and subscripts have the following meanings:

[0159] L is F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)NR xx R yy , -C(=O)OR xx , -C(=O)R xx , -NR xx R yy , -OH, -SF5 or a straight-chain or branched-chain alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 20 C atoms, preferably 1 to 12 C atoms, wherein one or more H atoms are optionally replaced by F or Cl (preferably F), -CN or a straight-chain or branched-chain alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 6 C atoms;

[0160] R xx and R yy each independently represents H or an alkyl group having 1 to 12 C atoms;

[0161] r is 0, 1, 2, 3 or 4;

[0162] s is 0, 1, 2 or 3;

[0163] t is 0, 1 or 2;

[0164] Z 21 and Z 22 independently and in each occurrence independently of one another are -O-, -S-, -CO-, -COO-, -OCO-, -S-CO-, -CO-S-, -O-COO-, -CO-NR 01 -, -NR 01 -CO-, -NR 01 -CO-NR 02 , -NR 01 -CO-O-, -O-CO-NR 01 -, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CH2CH2-, -(CH2)4-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR 01 -, -CY 01 =CY 02 -, -C≡C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond, preferably -COO-, -OCO-, -CO-O-, -O-CO-, -OCH2-, -CH2O-, -CH2CH2-, -(CH2)4-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -C≡C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond;

[0165] R 01 and R 02 each independently of one another represent H or an alkyl group having 1 to 12 C atoms;

[0166] Sp 1 in each occurrence represents a spacer group (Sp) as defined above or a single bond;

[0167] P 1 represents and

[0168] m is an integer from 1 to 60, preferably from 1 to 50, more preferably from 2 to 30, most preferably from 3 to 20.

[0169] More preferred compounds according to formula (1) are:

[0170]

[0171]

[0172] wherein the groups and subscripts have one of the meanings defined above.

[0173] Particularly preferred compounds according to formula (1) are:

[0174]

[0175]

[0176] wherein the groups and subscripts have one of the meanings defined above.

[0177] Most preferred compounds according to formula (1) are:

[0178]

[0179]

[0180]

[0181] wherein

[0182] n is an integer from 1 to 60, preferably from 1 to 36, and more preferably from 6 to 12; and

[0183] m is an integer from 1 to 60, preferably from 1 to 50, more preferably from 2 to 30, and most preferably from 3 to 20.

[0184] In the compounds of formulas M1 to M33 and the corresponding sub-formulas, the ring group

[0185]

[0186] wherein

[0187] L is, each time it appears, independently of one another, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)NR xx R yy , -C(=O)OR xx , -C(=O)R xx , -NR xx R yy , -OH, -SF5 or a straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 20 C atoms, preferably 1 to 12 C atoms, wherein one or more H atoms are optionally replaced by F or Cl (preferably F), -CN or a straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 6 C atoms; and

[0188] R xx and Ryy Defined according to the definition given above.

[0189] The compound represented by formula (1) can be prepared by any standard synthesis. Generally, the compound is retrosynthetically dissected into smaller units and gradually formed from suitable precursor compounds. For this purpose, known standard reactions can be used. It has been shown that it is particularly advantageous to attach the maleimide group P at a late stage of the synthesis, usually in the last step of the synthesis. 1 By doing so, undesired side reactions or premature polymerization of the compound can be avoided.

[0190] Preferably, the precursor represented by formula (3):

[0191] X-Sp 1 -(MG-Sp 1 ) m -X Formula (3)

[0192] reacts with to form the polymerizable compound represented by formula (1):

[0193] P 1 -Sp 1 -(MG-Sp 1 ) m -P 1 Formula (1)

[0194] wherein X is NH2;

[0195] P 1 is and

[0196] Sp 1 , MG and m have one of the definitions given above.

[0197] The second monomer(s) comprised in the polymerizable mixture according to the invention is / are one or more, preferably one, two, three or four, bi- or polyfunctional compounds capable of reacting with the first monomer to produce a copolymer.

[0198] Preferably, the second monomer is one or more, preferably one, two, three or four, bi- or polyfunctional compounds selected from organic compounds, polyhedral oligomeric silsesquioxane compounds and functionalized inorganic nanoparticles.

[0199] Even more preferably, the second monomer is one or more, preferably one, two, three or four, bi- or polyfunctional compounds comprising two or more polymerizable groups (P) (reactive groups), said polymerizable groups being selected from: preferably those that react with P in free radical or ionic chain polymerization or 2+2 cycloaddition 1The C═C double bond-containing group that reacts, preferably in a 4+2 cycloaddition (Diels-Alder reaction) with P 1 The group containing two conjugated C═C double bonds that reacts, preferably in a nucleophilic addition (Michael reaction) with P 1 The nucleophilic group that reacts and preferably in a 1,3-dipolar cycloaddition with P 1 The 1,3-dipolar group that reacts.

[0200] The preferred C═C double bond-containing groups are selected from:

[0201] CH2═CW 1 -COO-, CH2═CW 1 -CO-, CH2═CW 2 -(O) k3 -, CW 1 2═CH-CO-(O) k3 -, CW 1 2═CH-CO-NH-, CH2═CW 1 -CO-NH-, CH3-CH═CH-O-, CH2═CH-CH2-O-, (CH2═CH)2CH-O-CO-, (CH2═CH-CH2)2CH-O-CO-, (CH2═CH)2CH-O-, (CH2═CH-CH2)2N-, (CH2═CH-CH2)2N-CO-, CH2═CW 1 -CO-NH-, CH2═CH-(CO-O) k1 -Phe-(O) k2 -, CH2═CH-(CO) k1 -Phe-(O) k2 - or Phe-CH═CH-;

[0202] wherein

[0203] W 1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, preferably H or CH3;

[0204] W 2 represents H or alkyl having 1 to 5 C atoms, preferably H or CH3;

[0205] W 3 and W 4 each independently of one another represent H, Cl or alkyl having 1 to 5 C atoms, preferably H or CH3;

[0206] Phe represents 1,4-phenylene, which is optionally substituted by one or more groups L as defined above; and

[0207] k1, k2, and k3 each independently represent 0 or 1; and

[0208] k4 is an integer from 1 to 10.

[0209] Preferred groups containing two conjugated C═C double bonds are selected from: CW 1 2═CW 1 -CW 1 ═CW 1 -; where

[0210] W 1 represents H, F, Cl, CN, CF3, phenyl, an alkyl group having 1 to 5 C atoms, preferably H or CH3.

[0211] Preferred nucleophilic groups are selected from: HS-(CH2) k5 -CO-(O) k3 -, HS-(CH2) k5 -CO- k5 -(O) k3 -, HS-(CH2) k5 -O-CO- k5 -CO-NH- k5 -NH-CO- k2 -, HS-Phe-(O) k5 -CO-(O) k3 -, H2N-(CH2) k5 -CO- k5 -(O) k3 -, H2N-(CH2) k5 -O-CO- k5 -CO-NH- k5 -NH-CO- or H2N-Phe-(O) k2 -; where

[0212] k2 and k3 each independently represent 0 or 1; and

[0213] k5 is an integer from 0 to 10, preferably from 0 to 5, more preferably 0, 1, or 2.

[0214] Preferred 1,3-dipolar groups are selected from:

[0215] (nitrile ylide), (nitrile imide), (nitrile oxide), (diazo compound), (Azide), (Aza-ylide), (Aza-imide), (Nitrone), (Carbonyl-ylide), (Carbonyl-oxide), (Nitro), (Carbonyl-imine), (Azido-amine), (Nitroso-amine), (Azoxy-compound), or (Nitroso-oxide); wherein:

[0216] W 5 Each occurrence independently represents H, phenyl, alkyl having 1 to 5 C atoms, preferably phenyl or CH3.

[0217] Particularly preferred polymerizable groups (P) are selected from:

[0218] CH2=CW 1 -COO-, CH2=CW 1 -CO-, CH2=CW 2 -(O) k3 -, CW 1 2=CH-CO-(O) k3 -, CH3-CH=CH-O-, CH2=CH-CH2-O-, HS-(CH2) k5 -CO-(O) k3 -, HS-(CH2) k5 -CO-, HS-(CH2) k5 -(O) k3 -, HS-(CH2) k5 -O-CO-, H2N-(CH2) k5 -CO-(O) k3 -, H2N-(CH2) k5 -CO-, H2N-(CH2) k5 -(O) k3 - or H2N-(CH2) k5 -O-CO-; wherein

[0219] W 1 represents H, F, Cl, CN, CF3, phenyl, alkyl having 1 to 5 C atoms, preferably H or CH3;

[0220] W 2represents H or an alkyl group having 1 to 5 carbon atoms, preferably H or CH3;

[0221] W 3 and W 4 each independently of one another represent H, Cl or an alkyl group having 1 to 5 carbon atoms, preferably H or CH3;

[0222] k3 represents 0 or 1; and

[0223] k5 is an integer from 0 to 10, preferably from 0 to 5, more preferably 0, 1 or 2.

[0224] The organic compound preferably used as the second monomer is represented by the formula (4):

[0225]

[0226] wherein:

[0227] Q represents a hydrocarbon group having 1 to 50 carbon atoms, preferably 1 to 30 carbon atoms, which may optionally be substituted by one or more substituents L, where L is defined as above, and may optionally contain one or more heteroatoms selected from N, O and S;

[0228] P 2 represents the polymerizable group (P) as defined above; and

[0229] x is an integer from 2 to 10, preferably from 2 to 4, more preferably x = 2.

[0230] It is apparent from formula (4) that the group Q has x binding sites, each of which binds one of the x polymerizable groups P 2 one.

[0231] In a preferred embodiment, Q is represented by O(Sp 2 )2, N(Sp 2 )3, NH(Sp 2 )2, C(Sp 2 )4, CH(Sp 2 )3 or CH2(Sp 2 )2, where Sp 2 is a straight-chain alkylene chain having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, a branched alkylene chain having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms or an aromatic or heteroaromatic moiety having 3 to 14 carbon atoms, preferably an aromatic moiety having 6 to 14 carbon atoms, where each Sp 2 is bonded to the polymerizable group P 2 bonded.

[0232] In a further preferred embodiment, Q is represented by "Ar-Sp 3"-Ar", where Ar is an aromatic or heteroaromatic moiety having 3 to 14 carbon atoms, preferably an aromatic moiety having 6 to 14 carbon atoms, and Sp 3 is a straight-chain alkylene chain having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, a branched-chain alkylene chain having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms, or an aromatic or heteroaromatic moiety having 3 to 14 carbon atoms, preferably an aromatic moiety having 6 to 14 carbon atoms, wherein each Ar is bonded to a polymerizable group P 2 .

[0233] In a further preferred embodiment, Q is represented by "Sp 4 -Y-Sp 4 ", where Y is a monocyclic or polycyclic alkane moiety having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms, and Sp 4 is absent or is a straight-chain alkylene chain having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, a branched-chain alkylene chain having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms, or an aromatic or heteroaromatic moiety having 3 to 14 carbon atoms, preferably an aromatic moiety having 6 to 14 carbon atoms, wherein each Sp 4 is bonded to a polymerizable group P 2 .

[0234] In a particularly preferred embodiment, Q is selected from

[0235]

[0236] Particularly preferred organic compounds are selected from:

[0237]

[0238]

[0239] The polyhedral silsesquioxane compound preferably used as the second monomer is represented by the following structure:

[0240]

[0241] Wherein:

[0242] R is H, C1-C6-alkyl, C2-C6-alkenyl, C6-C 10 -aryl or C1-C6-alkoxy;

[0243] L is C1-C 12 -alkylene or C1-C 12 -oxyalkylene, more preferably C1-C6-alkylene or C1-C6-oxyalkylene, wherein one or more non-adjacent C atoms may each independently be replaced by -SiR05 R 06 - substitution, where R 05 and R 06 each independently of one another represent H or an alkyl group having 1 to 6 C atoms, more preferably H, CH3 or CH2CH3;

[0244] P 2 represents a polymerizable group (P) as defined above;

[0245] y is an integer from 6 to 12; x is an integer from 2 to 12, where

[0246] y - x ≥ 0.

[0247] Preferred C1-C6-alkyl substituents are: methyl, ethyl, propyl, butyl, pentyl and hexyl.

[0248] Preferred C2-C6-alkenyl substituents are: vinyl, propenyl, butenyl, pentenyl and hexenyl.

[0249] Preferred C6-C 10 -aryl substituents are: phenyl, tolyl, xylyl and naphthyl.

[0250] Preferred C1-C6-alkoxy substituents are: methoxy, ethoxy, propoxy, butoxy, pentyloxy and hexyloxy.

[0251] Preferred C1-C 12 -alkylene substituents are: methylene, ethylene, propylene, butylene, pentylene and hexylene.

[0252] Preferred C1-C 12 -oxyalkylene substituents are: methyleneoxy, ethyleneoxy, propyleneoxy, butyleneoxy, pentyleneoxy and hexyleneoxy.

[0253] Preferred C1-C4-alkyl substituents are: methyl, ethyl, propyl and butyl.

[0254] In a particularly preferred embodiment, the group L in structure (1) is selected from -(CH2) n -, -O-(CH2) n -, -SiH2-(CH2) n -, -OSiH2-(CH2) n -, -Si(CH3)2-(CH2) n -, -OSi(CH3)2-(CH2) n -, -Si(CH2CH3)2-(CH2) n - and -OSi(CH2CH3)2-(CH2) n-, where n is an integer from 1 to 6, preferably from 2 to 4, more preferably 3.

[0255] Particularly preferred polyhedral silsesquioxane compounds are based on the following Structures 2 to 5, where x R substituents are replaced by x (-L-P 2 ):

[0256]

[0257]

[0258] where R, L and P 2 have the same meanings as defined above; and where in Structure 2, x is an integer from 2 to 6; in Structure 3, x is an integer from 2 to 8; in Structure 4, x is an integer from 2 to 10; in Structure 5, x is an integer from 2 to 12.

[0259] The polyhedral silsesquioxane compounds shown above can be readily prepared from available precursors and can be easily incorporated into the polymerizable mixture by appropriate mixing conditions. For example, maleimide-substituted polyhedral silsesquioxanes and their preparation are described in US 2006 / 0009578 A1, the disclosure of which is incorporated herein by reference.

[0260] Preferred functionalized inorganic nanoparticles used as the second monomer are inorganic nanoparticles containing polymerizable groups P 2 on their surfaces, where P 2 represents the polymerizable group (P) as defined above. Preferred polymerizable groups (P) for the functionalized inorganic nanoparticles are selected from maleimide groups, dimethylmaleimide groups, acrylate groups, methacrylate groups, allyl ether groups and vinyl ether groups, which are bonded directly or via a group L to the surface of the inorganic nanoparticles.

[0261] Preferred functionalized inorganic nanoparticles are represented by the following structures:

[0262]

[0263] where represents the inorganic nanoparticle;

[0264] P 2 represents the polymerizable group (P);

[0265] L is a C1-C 12 -alkylene or a C1-C 12 -oxyalkylene, more preferably a C1-C6-alkylene or a C1-C6-oxyalkylene; and

[0266] x is an integer ≥2.

[0267] Preferred materials for the inorganic nanoparticles are selected from SiO2, TiO2, ZrO2, Fe2O3, MgTiO3, CaTiO3, SrTiO3, and BaTiO3. The inorganic nanoparticles can be solid or hollow.

[0268] Particularly preferred functionalized inorganic nanoparticles used as the second monomer in the present invention are:

[0269] wherein L and x are as defined above.

[0270] The above representation of the functionalized inorganic nanoparticles is for illustrative purposes only and should not be construed as limiting.

[0271] Preferably, the functionality of the functionalized inorganic nanoparticles used as the second monomer in the present invention is from 0.001 to 5 mmol / g, more preferably from 0.01 to 1 mmol / g, and most preferably from 0.05 to 0.5 mmol / g. The functionality represents the molar amount of the polymerizable group P 2 per unit mass of the functionalized inorganic nanoparticles.

[0272] The functionality can vary depending on the conditions used for functionalizing the inorganic nanoparticles. Those skilled in the art can select suitable conditions from methods known in the literature for functionalizing the inorganic nanoparticles, so that independently adapted functionalized nanoparticles with different polymerizable groups and different functionalities can be prepared. Suitable functionalized inorganic nanoparticles and their precursors are also available from commercial sources, for example, from Sigma Aldrich (e.g., 3-aminopropyl-functionalized silica, 660442 Aldrich) or nanoComposix, Inc., San Diego, USA.

[0273] The present invention further provides a method for forming a copolymer comprising repeating units derived from a first monomer and repeating units derived from a second monomer. The copolymer is a dielectric copolymer, which can be linear or crosslinked.

[0274] The method for forming the copolymer comprises the following steps:

[0275] (i) providing a polymerizable mixture according to the present invention; and

[0276] (ii) polymerizing the polymerizable mixture to obtain a copolymer.

[0277] The polymerizable mixture comprises the first monomer and the second monomer as defined above. Based on the total weight of the polymerizable monomers, preferably the total content of the first monomer in the polymerizable mixture is 50 to 99.9% by weight, more preferably 80 to 99% by weight, and most preferably 90 to 95% by weight. Based on the total weight of the polymerizable monomers, preferably the total content of the second monomer in the polymerizable mixture is 0.1 to 50% by weight, more preferably 1 to 20% by weight, and most preferably 5 to 10% by weight.

[0278] Preferably, the polymerizable mixture provided in step (i) is substantially free of solvent. Substantially free of solvent means that, based on the total weight of the polymerizable monomers, the total residual solvent content in the polymerizable starting materials is not more than 10% by weight, preferably not more than 5% by weight, and more preferably not more than 1% by weight. Alternatively, based on the total weight of the polymerizable monomers, preferably the polymerizable mixture provided in step (i) comprises one or more solvents, preferably in an amount greater than 10% by weight, more preferably in an amount greater than 25% by weight, and most preferably in an amount greater than 50% by weight.

[0279] Preferably, in step (ii), the polymerizable mixture is polymerized by radical or ionic chain polymerization or addition polymerization. Preferred addition polymerization reactions are cycloadditions, such as 2+2 cycloadditions, 4+2 cycloadditions (Diels-Alder reactions) or 1,3-dipolar cycloadditions, or nucleophilic additions, such as Michael reactions.

[0280] The above reaction types and the associated reaction conditions (such as catalysts, solvents, temperature, time, concentration, etc.) are known to those skilled in the art.

[0281] For example, radical or ionic polymerization can be carried out in the presence of radical or ionic polymerization initiators that can be activated by heat and / or photochemistry. Those skilled in the art are familiar with suitable radical and ionic polymerization initiators. For example, cycloadditions can occur photochemically or in the presence of a Lewis acid. Those skilled in the art are familiar with suitable photochemical conditions and suitable Lewis acids.

[0282] Preferably, the polymerizable mixture provided in step (i) further comprises one or more radical initiators. Preferred radical initiators are thermally activated radical initiators and / or photochemically activated radical initiators.

[0283] Preferred thermally activated free radical initiators are: tert-amyl peroxybenzoate, 4,4'-azobis(4-cyanovaleric acid), 1,1'-azobis(cyanocyclohexane), 2,2'-azobisisobutyronitrile (AIBN), benzoyl peroxide, 2,2-bis(tert-butylperoxy)butane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, 2,5-bis(tert-butylperoxy)-2,5-dimethyl-3-hexyne, bis(1-(tert-butylperoxy)-1-methylethyl)benzene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl hydroperoxide, tert-butyl peroxyacetate, tert-butyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, cumene hydroperoxide (CHP), cyclohexanone peroxide, dicumyl peroxide (DCP), lauroyl peroxide, 2,4-pentanedione peroxide, peracetic acid, and potassium persulfate.

[0284] Preferred photochemically activated free radical initiators are: acetophenone, anisil, benzil, benzoin, benzophenone, 2-benzoylbenzoic acid, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin ethyl ether, 4-benzoylbenzoic acid, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, methyl 2-benzoylbenzoate, 2-(1,3-benzod azol-5-yl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, (±)-camphorquinone, 2-chlorothioxanthone, 4,4'-dichlorobenzophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,4-diethylthioxanthone-9-one, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 1,4-dibenzoylbenzene, 2-ethylanthraquinone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-isopropylthioxanthone, lithium phenyl(2,4,6-trimethylbenzoyl)phosphite, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone, 2-isonitropropiophenone, 2-phenyl-2-(p-toluenesulfonyloxy)acetophenone, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide. Generally, such initiators are free radical polymerization initiators that can be photochemically activated.

[0285] Further preferred photochemically activated free radical initiators are:

[0286]

[0287]

[0288] Preferably, the initiator for free radical polymerization is thermally activated by exposure to heat or photochemically activated by exposure to radiation such as UV and / or visible light.

[0289] Exposure to heat involves exposure to an elevated temperature, preferably in the range of 40 to 200 °C, more preferably in the range of 50 to 180 °C.

[0290] Exposure to radiation involves exposure to visible light and / or UV light. Preferably, the visible light is electromagnetic radiation with a wavelength of > 380 to 780 nm, more preferably > 380 to 500 nm. Preferably, the UV light is electromagnetic radiation with a wavelength of ≤ 380 nm, more preferably a wavelength of 100 to 380 nm. More preferably, the UV light is selected from UV-A light with a wavelength of 315 to 380 nm, UV-B light with a wavelength of 280 to 315 nm, and UV-C light with a wavelength of 100 to 280 nm.

[0291] As a UV light source, a mercury vapor lamp or a UV laser can be used. As an IR light source, a ceramic emitter or an IR laser diode can be used, and for the visible light region, a laser diode can also be used.

[0292] Preferred UV light sources are light sources having: a) single wavelength radiation with a maximum < 255 nm, such as Hg low pressure discharge lamps at 254 nm and 185 nm, 193 nm ArF excimer lasers, and 172 nm Xe2 layers, or b) broad wavelength distribution radiation with wavelength components less than 255 m, such as undoped mercury low pressure discharge lamps.

[0293] In a preferred embodiment of the present invention, the light source is a xenon flash lamp. Preferably, the xenon flash lamp has a broad emission spectrum with a short wavelength component as low as about 200 nm.

[0294] Preferably, the polymerization in step (ii) is carried out within a time range of at most 5 hours, more preferably at most 1 hour, and most preferably at most 0.5 hours.

[0295] Further preferably, the polymerization of the polymerizable mixture in step (ii) is carried out at an elevated temperature, preferably in the temperature range of 25 to 200 °C, more preferably in the temperature range of 25 to 150 °C.

[0296] Also provided is a copolymer obtainable or obtained by the above method for forming a copolymer according to the present invention. The copolymer is preferably a linear or crosslinked copolymer, more preferably a linear copolymer.

[0297] There is also provided a copolymer comprising at least one repeating unit derived from the first monomer defined above and at least one repeating unit derived from the second monomer defined above.

[0298] More preferably, the repeating unit derived from the first monomer in the copolymer comprises a structural unit represented by the following formula (5):

[0299] [-Sp 1 -(MG-Sp 1 ) m -] Formula (5)

[0300] wherein Sp 1 , MG and m have one of the above definitions.

[0301] Preferably, the molecular weight Mw of the copolymer according to the present invention as determined by GPC is at least 2,000 g / mol, more preferably at least 4,000 g / mol, and even more preferably at least 5,000 g / mol. Preferably, the molecular weight Mw of the copolymer is less than 50,000 g / mol, and more preferably, the molecular weight Mw of the copolymer is in the range of 5,000 to 20,000 g / mol.

[0302] In addition, there is provided an electronic device comprising the copolymer according to the present invention. For the electronic device, preferably, the copolymer forms a dielectric layer, and more preferably, the dielectric layer forms part of a redistribution layer. The dielectric layer is used to electrically isolate one or more electronic components that are part of the electronic device from each other.

[0303] Finally, there is provided a manufacturing method for preparing a packaged microelectronic structure, wherein a dielectric layer is provided on the substrate, and the method comprises the following steps:

[0304] (1) applying the polymerizable mixture according to the present invention to the surface of the substrate; and

[0305] (2) curing the polymerizable mixture to form a dielectric layer.

[0306] Preferably, the polymerizable mixture further comprises one or more inorganic fillers. Preferred inorganic fillers are selected from nitrides, titanates, diamond, oxides, sulfides, sulfites, sulfates, silicates and carbides, which may optionally be surface-modified with a capping agent. More preferably, the fillers are selected from AlN, Al2O3, BN, BaTiO3, B2O3, Fe2O3, SiO2, TiO2, ZrO2, PbS, SiC, diamond and glass particles.

[0307] Preferably, based on the total weight of the polymerizable mixture, the total content of the inorganic filler in the polymerizable mixture is in the range of 0.001 to 90% by weight, more preferably 0.01 to 70% by weight, and most preferably 0.01 to 50% by weight.

[0308] Preferably, the polymerizable mixture applied in step (1) is substantially free of solvents. Substantially free of solvents means that, based on the total weight of the polymerizable monomers, the content of the total residual solvents in the polymerizable mixture is not more than 10% by weight, preferably not more than 5% by weight, and more preferably not more than 1% by weight.

[0309] However, depending on the application method used for applying the polymerizable mixture in step (1), preferably, the polymerizable mixture contains one or more solvents, based on the total weight of the polymerizable monomers, preferably in an amount greater than 10% by weight, more preferably in an amount greater than 25% by weight, and most preferably in an amount greater than 50% by weight.

[0310] The method of applying the polymerizable mixture in step (1) is not particularly limited. Preferred application methods for step (1) are dispensing, dip coating, screen printing, stencil printing, roll coating, spraying, slot coating, spin coating, stereolithography, gravure printing, flexographic printing or inkjet printing.

[0311] The polymerizable mixture of the present invention can be provided in a formulation suitable for gravure printing, flexographic printing and / or inkjet printing. For the preparation of such formulations, ink base formulations known in the prior art can be used.

[0312] Alternatively, the polymerizable mixture of the present invention can be provided in a formulation suitable for lithography. The lithography process allows the creation of a light pattern by transferring a geometric pattern from a photomask to a photocurable composition using light. Generally, such a photocurable composition contains a photochemically activatable free radical polymerization initiator. For the preparation of such formulations, photoresist base formulations known in the prior art can be used.

[0313] The average thickness of the polymerizable mixture layer applied in step (1) is preferably 1 to 50 μm, more preferably 2 to 30 μm, and most preferably 3 to 15 μm.

[0314] Preferably, the curing in step (2) is carried out by a radical or ionic chain polymerization reaction or an addition polymerization reaction. Preferred addition polymerization reactions are cycloadditions, such as 2+2 cycloaddition, 4+2 cycloaddition (Diels-Alder reaction) or 1,3-dipolar cycloaddition, or nucleophilic additions, such as Michael reaction. Preferred curing conditions correspond to the preferred polymerization conditions given above for the method of forming the copolymer.

[0315] Preferably, the polymerizable mixture applied in step (1) further comprises one or more radical initiators. Preferred radical initiators are as described above.

[0316] There is also provided a microelectronic device comprising an encapsulated microelectronic structure prepared according to the above manufacturing method.

[0317] The following examples further illustrate the invention but should in no way be construed as limiting the invention. Those skilled in the art will understand that various modifications, additions, and changes can be made to the invention without departing from the spirit and scope of the invention defined by the dependent claims. Examples

[0318] A) Synthesis of Oligomer 4

[0319] Step 1

[0320]

[0321] Step 2

[0322]

[0323] Step 1: Dissolve triethylamine (49.7 g, 0.49 mol) in 0.7 L of anhydrous toluene, and then add anhydrous methanesulfonic acid (48.6 g, 0.5 mol). Stir the mixture at room temperature for 10 minutes, and then carefully add diamine 2 (Priamine TM , Croda, 77.4 g, 0.14 mol) and dianhydride 1 (50 g, 0.07 mol). Next, heat the reaction mixture to reflux for 12 hours using a Dean - Stark apparatus.

[0324] Step 2: Cool the reaction mixture to room temperature, and slowly add maleic anhydride (8.7 g, 0.09 mol), and then add another 10 g of anhydrous methanesulfonic acid. Reheat the mixture to reflux for about 12 hours using a Dean - Stark water separator. After cooling to room temperature, add 200 ml of toluene and stop stirring. Carefully separate the upper (toluene solution) fraction, and wash the salt fraction twice with toluene (2 x 500 ml). Combine the toluene solutions and filter through a glass funnel tightly packed with silica gel. Wash the silica gel with an additional 100 ml of toluene and remove the toluene under reduced pressure to yield 70 g (85%) of a yellow waxy resin (4).

[0325] B) Synthesis of Additive (Maleimide)

[0326] 1. Synthesis of tris(2 - maleimidoethyl) - amine (5)

[0327] Step 1

[0328]

[0329] Step 2

[0330]

[0331] Step 1: Dissolve the furan-maleic anhydride adduct (Alfa Aesar, 28.5 g, 0.17 mol) in 750 ml of methanol. Add dropwise tris(2-aminoethyl)amine (Alfa Aesar, 5 g, 0.03 mol) dissolved in 250 ml of methanol at 0 °C. Next, heat the reaction mixture under reflux for 4 hours. Remove the methanol, and crystallize the concentrated solution (about 350 ml) overnight at 4 °C. Filter the obtained yellow crystals and wash them with ethyl acetate (19.6 g, 38%).

[0332] Step 2: Dissolve 7.4 g (0.013 mol) of the product obtained in Step 1 in 300 ml of toluene. Heat the solution to reflux. After 20 hours, remove the solvent under reduced pressure, dissolve the residual solid in ethyl acetate, and purify it by flash chromatography (DCM / ethyl acetate 60 / 40) to obtain maleimide (5). Yield: 4 g (84%).

[0333] 1 1H-NMR (500 MHz, CDCl3): δ = 6.68 (s, 6H), 3.52 (t, J = 6.6 Hz, 6H), 2.71 (t, J = 6.6 Hz, 6H) ppm.

[0334] Synthesis of 2,1,1′-((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis-(1H-pyrrole-2,5-dione) (8).

[0335] Step 1

[0336]

[0337] Step 2

[0338]

[0339] Step 1: Suspend 2,2′-bis(4-aminophenyl)hexafluoropropane (6) (abcr, 22.8 g, 66.8 mmol) in 95 ml of THF. Add maleic anhydride (Sigma, 13.2 g, 134 mmol), and stir the reaction mixture at room temperature for 1 h. Filter the obtained solid, wash it with ethyl acetate, and dry it under vacuum to obtain compound (7) (35.2 g, 99% yellow crystals).

[0340] 1H-NMR (500 MHz, DMSO-d6): δ = 12.94 (s, 2H), 10.56 (s, 2H), 7.72 (d, J = 9.0 Hz, 4H), 7.31 (d, J = 8.5 Hz, 4H), 6.49 (d, J = 12.0 Hz, 2H), 6.32 (d, J = 12.0 Hz, 2H) ppm.

[0341] Step 2: The 35.2 g (66.4 mmol) of the product obtained in Step 1 was treated with 125 mL of acetic anhydride, 6.5 g (80 mmol) of sodium acetate and butylated hydroxytoluene (80 mg). The reaction mixture was heated at 90 °C for 2 h. The solution was quenched with 400 ml of water, the precipitate was filtered, washed with methanol and dried in vacuo to give maleimide (8). Yield: 21.8 g of maleimide (8) (66%).

[0342] 1 H-NMR (500 MHz, DMSO-d6): δ = 7.58–7.47 (m, 8H), 7.24 (s, 4H) ppm.

[0343] 3. Synthesis of 3.1,1′-(cyclohexane-1,1-diylbis(4,1-phenylene))bis(1H-pyrrole-2,5-dione) (11).

[0344] Step 1

[0345]

[0346] Step 2

[0347]

[0348] Step 1: 1,1′-Bis(4-aminophenyl)cyclohexane (9) (abcr, 10 g, 37.5 mmol) was suspended in 40 ml of THF. Maleic anhydride (Sigma, 7.4 g, 75 mmol) was added and the reaction mixture was stirred at room temperature for 1 h. The solid obtained was filtered, washed with ethyl acetate and dried in vacuo to give compound (10) (16.5 g, 95% yellow crystals).

[0349] 1 H-NMR (500 MHz, DMSO-d6): δ = 12.82 (s, 2H), 10.36 (s, 2H), 7.62–7.44 (m, 4H), 7.36–7.21 (m, 4H), 6.46 (d, J = 12.1 Hz, 2H), 6.29 (d, J = 12.1 Hz, 2H), 2.22 (d, J = 5.7 Hz, 4H) 1.48–1.43 (m, 6H) ppm.

[0350] Step 2: The 16.5 g (35.7 mmol) of the product obtained in Step 1 was treated with 146 mL of acetic anhydride, 3.5 g (42.8 mmol) of sodium acetate and butylated hydroxytoluene (80 mg). The reaction mixture was heated at 90 °C for 2 h. The solution was quenched with 400 ml of water, the precipitate was filtered, washed with methanol and dried in vacuo. Yield: 10.1 g of maleimide (11) (66%).

[0351] 1 1H-NMR (500 MHz, DMSO-d6): δ = 7.51–7.35 (m, 4H), 7.34–7.20 (m, 4H), 7.16 (s, 4H), 2.39–2.23 (m, 4H) 1.60–1.39 (m, 6H) ppm.

[0352] C) Preparation of blends and free-standing films

[0353] General procedure for blend preparation: A solution of oligomer 4 in toluene (25 wt%) was mixed with different amounts of additives (dissolved in DMAc or cyclopentanone if required) and a suitable amount of free radical initiator.

[0354] Preparation of free-standing films: Free-standing polymer films were prepared by doctor-blading onto glass substrates followed by thermal or photo-induced curing (more detailed conditions are given in the different examples). The films could be removed from the glass substrates by rinsing with water.

[0355] Mechanical and thermal properties:

[0356] Tensile strength and elongation at break (E2B) were measured on a mechanical testing machine (500 N Zwicki). The Young's modulus (modulus) was calculated by dividing the tensile stress in the elastic (initial, linear) part of the physical stress-strain curve by the tensile strain. The film dimensions were typically 25 mm long, 15 mm wide and the thickness was between 25 - 100 microns. Measurements were carried out according to the following parameter settings: Pre-measurement: 0.1 N at a tensile rate of 10 mm / min; Main tensile speed: 50 mm / min. All experiments were carried out at room temperature (23 ± 2 °C).

[0357] Thermomechanical analysis (TMA) was carried out in tensile mode on a 402F3 TMA (Netzsch). The coefficient of thermal expansion (CTE) was measured in the range 20 - 300 °C under N2 atmosphere.

[0358] Example 1: Oligomer 4 with 1,1′-(methylenedi-4,1-phenylene)-bis-maleimide (Aldrich, BMI1)

[0359]

[0360] (a) Curing conditions: Oligomer 4 + 1 wt% AIBN, 1 hour at 175 °C (hot plate)

[0361]

[0362] ＊ CTE between 25 - 35 °C

[0363] # CTE between 140 - 170 °C

[0364] (b) Curing conditions: Oligomer 4 + 10 wt% BMI1 + 1 or 5 wt% DCP, 1 hour at 175 °C (hot plate)

[0365]

[0366] ＊ CTE between 25 - 35 °C

[0367] # CTE between 140 - 170 °C

[0368] Example 2: Oligomer 4 and maleimide 5

[0369]

[0370] (a) Curing conditions:

[0371] Oligomer 4 + 5 wt% maleimide (5) + 5 wt% N1919T (Adeka), 10 minutes at room temperature, 10 minutes at 100 °C (hot plate), 10 J / cm 2 (broadband), 30 minutes at 175 °C (hot plate).

[0372] 0 wt% maleimide (5) 5 wt% maleimide (5) Modulus [GPa] 0.077 0.416 E2B [%] 277 141 CTE [ppm / K] <![CDATA[1232 ＊ > <![CDATA[633 ＊ |-32 # >

[0373] ＊ CTE between 25 - 35 °C

[0374] # CTE between 140 - 170 °C

[0375] (b) Curing conditions: Oligomer 4 + 5 wt% maleimide (5) + 5 wt% Irgacure OXE - 02 (BASF), 10 minutes at room temperature, 10 minutes at 100 °C (hot plate), 10 J / cm 2 (broadband), 30 minutes at 175 °C (hot plate).

[0376] 0 wt% maleimide (5) 5 wt% maleimide (5) Modulus [GPa] 0.120 0.668 E2B [%] 210 98 CTE [ppm / K] <![CDATA[2465 ＊ > <![CDATA[633 ＊ |-32 # >

[0377] ＊ CTE between 25 - 35 °C

[0378] # CTE between 140 - 170 °C

[0379] Example 3: Oligomer 4 and Pentaerythritol Tetraacrylate (Sigma - Aldrich, Acrylate 1)

[0380]

[0381] Curing conditions: Oligomer 4 + various amounts of Acrylate 1 + 5 wt% DCP, 175 °C (hot plate) for 1 hour.

[0382]

[0383] ＊ CTE between 25 - 35 °C

[0384] # CTE between 140 - 170 °C

[0385] Example 4: Oligomer 4 and (Octahydro - 1H - 4,7 - methanoindene - 2,5 - diyl)bis(methylene) diacrylate (Sigma - Aldrich, Acrylate 2)

[0386]

[0387] Curing conditions: Oligomer 4 + various amounts of Acrylate 2 + 5 wt% DCP, 175 °C (hot plate) for 1 hour.

[0388]

[0389] ＊ CTE between 25 - 35 °C

[0390] # CTE between 140 - 170 °C

[0391] Example 5: Oligomer 4 and Dimethylmaleimide - SiO2 (50 nm, nanoComposix) (DMMI - SiO2)

[0392]

[0393] (a) Curing conditions: Oligomer 4 + DMMI - SiO2 (nanoComposix, Inc., 50 nm) + 5 wt% OXE02, room temperature for 10 minutes, 100 °C (hot plate) for 10 minutes, 10 J / cm 2 (broadband).

[0394]

[0395] (b) Curing conditions: Oligomer 4 + DMMI-SiO2 (nanoComposix, Inc., 50 nm) + 1 wt% AIBN, 175 °C (hot plate) for 1 hour.

[0396]

[0397] Example 6: Oligomer 4 and acrylate-POSS (Hybridplastics)

[0398]

[0399] Curing conditions: Oligomer 4 + various amounts of acrylate-POSS ( MA0736 – Acrylo POSS cage mixture) + 5 wt% DCP, 175 °C (hot plate) for 1 hour.

[0400]

[0401] ＊ CTE between 25 - 35 °C

[0402] # CTE between 140 - 170 °C

[0403] Example 7: Oligomer 4 and maleimide (8)

[0404]

[0405] Curing conditions: Oligomer 4 + various amounts of maleimide (8) + 5 wt% Irgacure OXE-02 (BASF), room temperature for 10 minutes, 100 °C (hot plate) for 10 minutes, 10 J / cm 2 (broadband), 175 °C (hot plate) for 30 minutes.

[0406]

[0407] Example 8: Oligomer 4 and maleimide (11)

[0408]

[0409] Curing conditions: Oligomer 4 + various amounts of maleimide (11) + 5 wt% Irgacure OXE-02 (BASF), room temperature for 10 minutes, 100 °C (hot plate) for 10 minutes, 10 J / cm 2 (broadband), 175 °C (hot plate) for 30 minutes.

[0410]

Claims

1. A polymerizable mixture comprising a first monomer and a second monomer, wherein the first monomer is one or more compounds selected from compounds M1 to M31 wherein: m is an integer from 2 to 30 P 1 denotes Sp 1 represents, each time it appears, a spacer group (Sp); Z 21 and Z 22 independently and, each time it appears, independently of one another, is -S-, -CO-, -COO-, -OCO-, -S-CO-, -CO-S-, -SCH2-, -CH2S-, -CF2S-, -SCF2-, -CH2CH2-, -(CH2)4-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=CR 01 -, -CY 01 =CY 02 -, -C≡C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond; R 01 and R 02 each independently represent H or an alkyl group having 1 to 12 C atoms; L is F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)NR xx R yy , -C(=O)OR xx , -C(=O)R xx , -NR xx R yy , -OH, -SF5 or a straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 20 C atoms, where one or more H atoms are optionally replaced by F or Cl, -CN or a straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 6 C atoms; R xx and R yy each independently represent H or an alkyl group having 1 to 12 C atoms; Y 01 and Y 02 each independently of the other represents H, an alkyl group having 1 to 12 C atoms, aryl, F, Cl or CN; and r is 0, 1, 2, 3 or 4; s is 0, 1, 2 or 3; t is 0, 1 or 2; and wherein the second monomer is a difunctional or polyfunctional compound selected from one or more of an organic compound, a polyhedral oligomeric silsesquioxane compound, and a functionalized inorganic nanoparticle, wherein (a) the organic compound is represented by formula (4): wherein: Q represents a hydrocarbon group having 1 to 50 carbon atoms, which may be substituted by one or more substituents L, where L is defined as above, and may contain one or more heteroatoms selected from N, O, and S; P 2 represents a polymerizable group (P) selected from a group containing a C═C double bond, a group containing two conjugated C═C double bonds, a nucleophilic group, and a 1,3-dipolar group; x is an integer from 2 to 10; (b) the polyhedral oligomeric silsesquioxane compound is represented by the following structure: wherein: R is H, C1-C6-alkyl, C2-C6-alkenyl, C6-C 10 -aryl or C1-C6-alkoxy; L is C1-C 12 -alkylene or C1-C 12 -oxyalkylene, wherein one or more non-adjacent C atoms may each independently be replaced by -SiR 05 R 06 -, wherein R 05 and R 06 each independently represent H or an alkyl group having 1 to 6 C atoms; P 2 represents an aggregatable group (P) as defined above; y is an integer from 6 to 12; and x is an integer from 2 to 12, where y - x ≥ 0; or (c) The functionalized inorganic nanoparticles comprise polymerizable groups P on their surface 2 , wherein P 2 represents an aggregatable group (P) as defined above.

2. The polymerizable mixture according to claim 1, wherein the spacer group Sp is selected from the formula Sp'-X', such that the group "P 1 -Sp 1 -” corresponds to the formula "P 1 -Sp'-X'-” wherein: Sp' represents (a) A straight-chain or branched alkylene having 1 to 40 C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN, and wherein, furthermore, one or more non-adjacent CH2 groups may each independently of one another be replaced by -S-, -NH-, -NR 01 -, -SiR 01 R 02 -, -CO-, -COO-, -OCO-, -S-CO-, -CO-S-, -NR 01 -CO-NR 01 -, -CH=CH- or -C≡C- in such a way that O and / or S atoms are not directly connected to one another, or (b)-Sp x -G-Sp y -, where Sp x and Sp y each independently represent an alkylene group having 1 to 20 C atoms or a single bond; G represents a cycloalkylene group having 3 to 20 C atoms, which is optionally mono- or polysubstituted by an alkyl group having 1 to 20 C atoms; X' represents -S-, -CO-, -COO-, -OCO-, -CO-NR 01 -, -NR 01 -CO-, -NR 01 -CO-NR 01 -, -SCH2-, -CH2S-,, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=C-, -N=N-, -CH=CR 01 -, -CY 01 =CY 02 -, -C≡C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond; R 01 and R 02 each independently represents H or an alkyl group having 1 to 12 C atoms; and Y 01 and Y 02 each independently represents H, F, Cl or CN.

3. The polymerizable mixture according to claim 1 or 2, wherein the spacer group Sp is selected from -(CH2) p1 -, -CH2CH2-S-CH2CH2-, -CH2CH2-NH-CH2CH2-, -(SiR 01 R 02 -O) p1 -, -(CH2) p1 -(cyclo-C6H8R 01 R 02 )-(CH2) p1 -, and wherein: p1 is an integer from 1 to 60; q1 is an integer from 1 to 12; and R 01 and R 02 each independently represent H or an alkyl group having 1 to 12 C atoms.

4. A method for forming a copolymer, comprising the steps of: (i) providing the polymerizable mixture according to any one of claims 1 to 3; and (ii) polymerizing the polymerizable mixture to obtain a copolymer.

5. The method for forming a copolymer according to claim 4, wherein the polymerizable mixture further comprises one or more radical initiators.

6. A copolymer obtainable by the method for forming a copolymer according to claim 4 or 5.

7. A copolymer comprising at least one repeating unit derived from the first monomer as defined in any one of claims 1 to 3 and at least one repeating unit derived from the second monomer as defined in any one of claims 1 to 3.

8. An electronic device comprising the copolymer according to claim 6 or 7.

9. The electronic device according to claim 8, wherein the copolymer forms a dielectric layer.

10. A manufacturing method for preparing a packaged microelectronic structure, wherein, A substrate is provided with a dielectric layer, wherein the method comprises the steps of: (1) applying the polymerizable mixture according to any one of claims 1 to 3 to the surface of the substrate; and (2) curing the polymerizable mixture to form a dielectric layer.

11. The manufacturing method for preparing a packaged microelectronic structure according to claim 10, wherein the polymerizable mixture further comprises one or more radical initiators.

12. A microelectronic device comprising a packaged microelectronic structure obtainable by the manufacturing method according to claim 10 or 11.

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