阅读说明：本技术 介电材料 (Dielectric material ) 是由 F·迈耶 G·拉比格 K·克珀 于 2019-01-21 设计创作，主要内容包括：本发明涉及一类新型聚合物,其可用作介电材料以制备电子器件中的钝化层。该聚合物由具有介晶基团的可聚合化合物制备,并且它们提供优异的成膜能力和优异的机械性能,并且具有低介电常数和低热膨胀系数(CTE)。还提供了一种形成所述聚合物的方法和含有所述聚合物作为介电材料的电子器件。此外,本发明涉及一种用于制备封装的微电子结构的制造方法,以及涉及一种包括通过所述制造方法形成的所述封装的微电子结构的微电子器件。(The present invention relates to a novel class of polymers useful as dielectric materials for preparing passivation layers in electronic devices. The polymers are prepared from polymerizable compounds having mesogenic groups, and they provide excellent film-forming ability and excellent mechanical properties, and have a low dielectric constant and a low Coefficient of Thermal Expansion (CTE). Also provided are a method of forming the polymer and an electronic device containing the polymer as a dielectric material. Furthermore, the present invention relates to a manufacturing method for preparing an encapsulated microelectronic structure, and to a microelectronic device comprising said encapsulated microelectronic structure formed by said manufacturing method.)

1. A polymerizable compound represented by formula (1):

P¹-Sp¹-(MG-Sp¹)_m-P¹formula (1)

Wherein:

m is an integer of 1 to 60;

P¹represents a polymerizable group (P);

Sp¹in each case representing a spacer group (Sp) or a single bond;

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

-(A²¹-Z²¹)_k-A²²-(Z²²-A²³)_l-formula (2)

Wherein:

A²¹to A²³Independently and independently for each occurrence, an aryl, heteroaryl, heterocyclyl, alicyclic group or cyclic imide group, which is optionally substituted by one or more identical or different groups L;

Z²¹and Z²²Independently and independently of each other at each occurrence-O-, -S-, -CO-, -COO-, -OCO-, -S-CO-, -CO-S-, -O-COO-, -CO-NR⁰¹-、-NR⁰¹-CO-、-NR⁰¹-CO-NR⁰²、-NR⁰¹-CO-O-、-O-CO-NR⁰¹-、-OCH₂-、-CH₂O-、-SCH₂-、-CH₂S-、-CF₂O-、-OCF₂-、-CF₂S-、-SCF₂-、-CH₂CH₂-、-(CH₂)₄-、-CF₂CH₂-、-CH₂CF₂-、-CF₂CF₂-、-CH＝N-、-N＝CH-、-N＝N-、-CH＝CR⁰¹-、-CY⁰¹＝CY⁰²-, -C.ident.C-, -CH-COO-, -OCO-CH-or a single bond;

R⁰¹and R⁰²Each independently of the other represents H or an alkyl group having 1 to 12 carbon atoms;

l is F, Cl, Br, I, -CN, -NO₂、-NCO、-NCS、-OCN、-SCN、-C(＝O)NR^xxR^yy、-C(＝O)OR^xx、-C(＝O)R^xx、-NR^xxR^yy、-OH、-SF₅Or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 20C atoms, wherein one or more H atoms are optionally replaced by F or Cl, -CN or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 6C atoms;

R^xxand R^yyIndependently of one another, H or an alkyl radical having 1 to 12 carbon atoms;

Y⁰¹and Y⁰²Each independently of the others represents H, alkyl having 1 to 12 carbon atoms, aryl, F, Cl or CN; and

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

2. The polymerizable compound according to claim 1, wherein the polymerizable group P is selected from a group containing a C ═ C double bond or a C ≡ C triple bond, and a group suitable for polymerization by a ring-opening reaction.

3. The polymerizable compound of claim 1 or 2 wherein the polymerizable group P is selected from CH₂＝CW¹-COO-、CH₂＝CW¹-CO-、

wherein:

W¹represents H, F, Cl, CN, CF₃Phenyl or alkyl having 1 to 5 carbon atoms;

W²represents H or an alkyl group having 1 to 5 carbon atoms;

W³and W⁴Independently of one another, H, Cl or an alkyl radical having 1 to 5 carbon atoms;

phe represents 1, 4-phenylene optionally substituted with one or more groups L as defined above but different from P-Sp; and

k₁、k₂and k₃Represents independently of one another 0 or 1; and

k₄is an integer from 1 to 10.

4. The polymerizable compound of one or more of claims 1-3 wherein the spacer group Sp is selected from the formula Sp '-X', such that the group "P-Sp-" corresponds to the formula "P-Sp '-X' -", wherein:

sp' represents

(a) Straight-chain or branched alkylene having 1 to 40, preferably 1 to 30, carbon atoms, which is optionally mono-or polysubstituted with F, Cl, Br, I or CN, and wherein, in addition, one or more non-adjacent CH' s₂The radicals may be one anotherIndependently by-O-, -S-, -NH-, -NR-⁰¹-、-SiR⁰¹R⁰²-、-CO-、-COO-、-OCO-、-OCO-O-、-S-CO-、-CO-S-、-NR⁰¹-CO-O-、-O-CO-NR⁰¹-、-NR⁰¹-CO-NR⁰¹-, -CH-or-C.ident.C-in such a way that the O and/or S atoms are not directly connected to one another, or

(b)-Sp^x-G-Sp^y-, in which Sp^xAnd Sp^yIndependently of one another, an alkylene group having 1 to 20 carbon atoms or a single bond; g represents a cycloalkylene group having 3 to 20 carbon atoms, optionally mono-or polysubstituted with an alkyl group having 1 to 20 carbon atoms;

x' represents-O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR⁰¹-、-NR⁰¹-CO-、-NR⁰¹-CO-NR⁰¹-、-OCH₂-、-CH₂O-、-SCH₂-、-CH₂S-、-CF₂O-、-OCF₂-、-CF₂S-、-SCF₂-、-CF₂CH₂-、-CH₂CF₂-、-CF₂CF₂-、-CH＝N-、-N＝C-、-N＝N-、-CH＝CR⁰¹-、-CY⁰¹＝CY⁰²-, -C.ident.C-, -CH-COO-, -OCO-CH-or a single bond;

R⁰¹and R⁰²Independently of one another, H or an alkyl radical having 1 to 12 carbon atoms; and

Y⁰¹and Y⁰²Independently of one another, H, F, Cl or CN.

5. The polymerizable compound of one or more of claims 1-4, wherein the spacer group Sp is selected from- (CH)₂)_p1-、-(CH₂CH₂O)_q1-CH₂CH₂-、-CH₂CH₂-S-CH₂CH₂-、-CH₂CH₂-NH-CH₂CH₂-、-(SiR⁰¹R⁰²-O)_p1-、-(CH₂)_p1- (Ring-C)₆H₈R⁰¹R⁰²)-(CH₂)_p1-, and

wherein:

p1 is an integer from 1 to 60;

q1 is an integer from 1 to 12; and

R⁰¹and R⁰²Each independently of the other represents H or an alkyl group having 1 to 12 carbon atoms.

6. Polymerizable compound according to one or more of claims 1 to 5, wherein A²¹To A²³Independently represent, and in the case of multiple occurrences independently represent, a moiety selected from the following groups a) to e):

a) trans-1, 4-cyclohexylene, 1, 4-cyclohexenylene and 4,4' -dicyclohexylene, in which one or more non-adjacent CH groups₂The radicals may be replaced by-O-and/or-S-, and one or more H atoms may be replaced by a radical L;

b)1, 4-phenylene, 1, 3-phenylene, 4' -biphenylene, 2, 5-thiophene and 2, 6-dithieno [3,2-b:2',3' -d ] thiophene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by a group L;

c) tetrahydropyran-2, 5-diyl, 1, 3-diylAlk-2, 5-diyl, tetrahydrofuran-2, 5-diyl, cyclobut-1, 3-diyl, piperidine-1, 4-diyl, thiophene-2, 5-diyl and selenophene-2, 5-diyl, which may be substituted by one or more L groups;

d) saturated, partially unsaturated or fully unsaturated and optionally substituted polycyclic radicals having 5 to 20 ring carbon atoms, one or more of which may also be replaced by heteroatoms, preferably from the group consisting of bicyclo [1.1.1] pentane-1, 3-diyl, bicyclo [2.2.2] octane-1, 4-diyl, spiro [3.3] heptane-2, 6-diyl, tricyclo [3.3.1.1] decane-1, 3-diyl,

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, and wherein

M represents-O-, -S-, -CH₂-、-CHY⁰³-or-CY⁰³Y⁰⁴-；

Y⁰³、Y⁰⁴Independently of one another represent the above for R⁰¹、F、Cl、CN、OCF₃Or CF₃One of the meanings given, and preferably H, F, Cl, CN, OCF₃Or CF₃；

W⁵、W⁶Independently of one another represent-CH₂CH₂-、-CH＝CH-、-CH₂-O-、-O-CH₂-、-C(R^cR^d) -or-O-;

R^c，R^dindependently of one another, H or an alkyl radical having 1 to 6 carbon atoms, preferably H, methyl or ethyl; and

R⁰³、R⁰⁴h, F, straight-chain or branched alkyl having 1 to 12 carbon atoms, in which one or more H atoms may be replaced by F;

e) a cyclic imide selected from the group consisting of:

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.

7. A method for forming a polymer comprising the steps of:

(i) providing a polymerizable starting material comprising one or more polymerizable compounds according to one or more of claims 1-6; and

(ii) polymerizing the polymerizable starting material.

8. A method of forming a polymer according to claim 7, wherein the polymerizable starting material further comprises one or more other polymerizable compounds capable of reacting with the polymerizable compounds to form a copolymer.

9. A method of forming a polymer according to claim 7 or 8, wherein the polymerisable starting material is polymerised in step (ii) by free radical polymerisation or ionic polymerisation or by exposure to radiation.

10. Polymer obtainable by a process for forming a polymer according to one or more of claims 7-9.

11. Polymer comprising at least one recurring unit derived from a polymerizable compound of formula (1) as defined in one or more of claims 1 to 6.

12. The polymer of claim 11, wherein the repeat unit comprises a structural unit represented by formula (4):

[-Sp¹-(MG-Sp¹)_m-]formula (4)

Wherein Sp¹MG and m are as defined in one or more of claims 1-6.

13. An electronic device comprising the polymer of claim 11 or 12.

14. The electronic device of claim 13, wherein the polymer forms a dielectric layer.

15. A manufacturing process for preparing an encapsulated microelectronic structure, wherein a substrate is provided with a coating comprising one or more polymerized liquid crystal monomers, wherein the process comprises the steps of:

(1) applying a polymerizable composition comprising one or more polymerizable compounds according to one or more of claims 1-6 onto a surface of a substrate; and

(2) curing the polymerizable composition to form a dielectric layer.

16. The method of making a packaged microelectronic structure according to claim 15, wherein the polymerizable composition further comprises one or more other polymerizable compounds capable of reacting with the polymerizable compound to form a copolymer.

17. The method of making a microelectronic structure for the preparation of an encapsulation according to claim 15 or 16, wherein the polymerizable composition further comprises one or more inorganic filler materials.

18. Microelectronic device comprising an encapsulated microelectronic structure obtainable by a manufacturing method according to one or more of claims 15-17.

Technical Field

The present invention relates to a novel class of polymers useful as dielectric materials for the preparation of passivation layers in encapsulated electronic devices. The polymers are prepared from polymerizable compounds having mesogenic groups. Such compounds are also known as Reactive Mesogens (RMs). The polymers thus obtained are therefore materials having the characteristic of retaining the liquid crystal in their structure, and they provide excellent film-forming ability and excellent mechanical properties, such as good elongation at break and good tensile strength properties. In addition, the polymers are characterized by a low dielectric constant and a low Coefficient of Thermal Expansion (CTE). In addition to this, they are photostructurable and are particularly suitable for use in various applications in electronic packaging, such as passivation and die (die) bonding of conductive or semiconductive components, and as a main component for the preparation of substrates for printed circuit boards.

The polymerizable compound forming the polymer has an oligomer structure having a repeating unit containing a Mesogenic Group (MG) in the middle of the molecule and, at each end of the molecule, a polymerizable group(s) (P). Also provided are a method of forming the polymer and an electronic device containing the polymer as a dielectric material. Furthermore, the present invention relates to a manufacturing method for producing an encapsulated microelectronic structure, wherein a dielectric polymer layer is formed from the polymerizable compound, and to a microelectronic device comprising the encapsulated microelectronic structure, which is obtained or obtainable by the manufacturing method.

The manufacturing method according to the invention allows a cost-effective and reliable manufacturing of microelectronic devices, wherein the number of defective products due to mechanical deformations (warpage) caused by undesired thermal expansion is significantly reduced. Polymerization can occur at significantly lower temperatures, thus resulting in lower thermal stresses during fabrication, which reduces the waste of defective microelectronic devices, allowing for resource efficient and sustainable production.

Background

Reactive Mesogens (RMs), when polymerized at temperatures at which they exhibit a thermotropic Liquid Crystalline (LC) phase (typically nematic, cholesteric or smectic), give anisotropic polymers that retain the liquid crystalline state. In particular, optical anisotropy has been widely used in the field of compensated and brightness enhanced optical films in flat panel displays, especially liquid crystal displays.

In addition to their widespread use in liquid crystal displays and displays, the advantages of liquid crystal materials in other types of applications due to their particular physical properties have been investigated (r.stannarius, nat. mat.2009,8, 617-618; and j.p.f. lagerwall et al, Current application. phys.2012,12, 1387-1412). In particular, highly ordered anisotropic polymer networks are an interesting class of materials with a diverse range of applications (D.J.Broer et al, Lagmuir 2014,30, 13499-. However, in most cases, the LC polymers or the corresponding monomers from which they are prepared do not have the optimum properties required for the respective application.

WO2012/152409a1 relates to polymer particles having optical anisotropy and shape anisotropy comprising at least one reactive mesogenic monomer unit, methods of preparing the same, the use of these particles for the preparation of optical, electrooptical, electronic, electrochemical, electrophotographic, electrowetting and electrophoretic displays and/or devices and security, cosmetic, decorative and diagnostic applications, and electrophoretic fluids and displays comprising said polymer particles. In particular, the polymer particles have monomer units of at least one RM having at least two polymerizable groups, at least one polymerizable dye as a comonomer, optionally at least one crosslinking comonomer, optionally at least one ionic comonomer and optionally at least one polymerizable stabilizer.

Various methods for preparing liquid crystalline polymers from RMs and for preparing RM starting materials are known in the art. For example, Siemens meyer et al describe a process for producing mixtures of LC compounds, in which at least one starting component consists of a mixture of at least two compounds and the mixture is reacted with at least one other starting component to form a statistical mixture (WO96/04351A 1).

In addition to efficient preparation methods of LC compounds, suitable polymerization methods for forming anisotropic polymer networks are also the focus of interest. The applicability of various reactive functional groups in photo-initiated polymerization reactions was investigated. The most widespread reactive functional groups are acrylates and methacrylates, which are particularly suitable for UV-induced free radical polymerization due to their high polymerization rate (D.J. Broer et al, Lagmuir 2014,30, 13499-13509). However, UV curing is not suitable for all types of applications.

Mixtures of polymerizable liquid crystalline monomers (reactive mesogens) can be used to prepare films that can be cured by thermally or photo-initiated polymerization. Films prepared in this manner are relatively thin and contain highly crosslinked rigid plastic polymers with significant dimensional stability. However, these films are relatively brittle and exhibit very low elasticity. On the other hand, if the degree of crosslinking is reduced, a dimensionally stable polymer film cannot be obtained.

US 6,261,481B1 describes an organic insulating composition providing good thermal conductivity. The insulation composition comprises a Liquid Crystal (LC) resin comprising a polymerization product of a resin composition comprising a monomer having a mesogenic group. The composition has a thermal conductivity in the directions orthogonal to each other of 0.4W/mK or more. The monomer contained in the resin composition has a mesogenic group, preferably an epoxy group, which is thermally polymerizable under acid catalysis. Preferably, the resin composition is heated under conditions such that the monomer having a mesogenic group is partially aligned at the start of polymerization, so that anisotropic properties based on the partial alignment are frozen in the polymer.

US2008/0075961a1 and US2017/0152418a1 relate to maleimide adhesive films prepared from thermosetting maleimide resins containing imide chain-extended mono-, di-, and polymaleimide compounds. The maleimide adhesive films are photostructurable 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, which may impart a preferential direction or partial alignment of the compounds in the film. This results in poor performance in terms of mechanical stability and thermal conductivity. These materials also typically exhibit relatively low glass transition points, which in turn affects their thermal expansion properties.

KR 20160052234 a describes a photocurable insulating resin composition and a printed circuit board using the same. The photocurable insulating resin composition comprises a photocurable liquid crystal oligomer; a photo-curable graphene oxide; and a photocurable metal alkoxide. However, the photocurable liquid crystal oligomer does not contain a plurality of mesogenic groups linked together by spacer groups. This results in an unfavorable solubility distribution and the energy for photocuring is very high.

Electronic package

As solid state transistors began to replace vacuum tube technology, electronic components such as resistors, capacitors and diodes became directly mountable into the card's printed circuit board through their leads, thereby establishing a basic building block or package level that is still in use. Complex electronic functions typically require more individual components than can be interconnected on a single printed circuit card. The performance of multi-layer cards has been accompanied by the development of three-dimensional packages of daughter cards onto multi-layer motherboards. Integrated circuits allow many discrete circuit elements, such as resistors and diodes, to be embedded in a single, relatively small component called an integrated circuit chip or die. However, although the degree of circuit integration is incredible, more than one package level is typically required, in part because of the technology of the integrated circuit itself. Integrated circuit chips are very fragile, with very small terminals. The first level packaging performs the primary functions of mechanical protection, cooling, and the ability to provide electrical connections to the delicate integrated circuits. Since some components (high power resistors, mechanical switches, capacitors) are not easily integrated on the chip, at least one additional packaging level, such as a printed circuit card, is used. For very complex applications, such as large computers, multiple levels of packaging are required.

Various advanced packaging technologies exist to meet the demands of today's semiconductor industry. Leading advanced packaging technologies-Wafer Level Package (WLP), fan-out wafer level package (FOWLP), 2.5D interposer, chip-on-chip stack, package-on-package stack, embedded IC-all require structuring of thin substrates, redistribution layers and other components such as high resolution interconnects. The end consumer market presents a continuing push for lower prices and higher functionality for smaller and thinner devices. This drives the need for next generation packages with finer features and increased reliability at competitive manufacturing costs.

Wafer Level Packaging (WLP) is a technique of packaging integrated circuits that are still part of a wafer, as opposed to the more conventional method of dicing a wafer into individual circuits (wafers) and then packaging them. WLP is basically a true Chip Scale Package (CSP) technology, since the resulting package is practically the same size as the die. Wafer level packaging allows integration of wafer processing, packaging, testing, and burn-in at the wafer level in order to streamline the manufacturing process that a device experiences from the beginning of silicon to customer shipment. The main application areas of WLP are smart phones and wearable devices due to their size limitations. The functions provided by the WLP in the smartphone or wearable device include: compass, sensor, power management, wireless, etc. Wafer level chip scale package (WL-CSP) is one of the smallest packages currently available on the market.

Fan-out wafer level packaging (FOWLP) is one of the latest packaging trends in microelectronics: FOWLP has high miniaturization potential in terms of both package volume and package thickness. The technological base of FOWLP is a reconfigured, embedded chip coated wafer and thin film rewiring layer that together form a Surface Mount Device (SMD) compatible package. The main advantages of FOWLP are very thin due to substrate-less packaging, low thermal resistance, good high frequency characteristics due to short and planar electrical connections and bumpless chip connections rather than, for example, wire bonding or solder contacts.

For electronic packaging, different types of materials are required from which the substrate, the conductive connections and the insulating or passivation coating are made. The substrate insulator material for multi-chip and single-chip modules is selected from one of two broad classes of materials, organic and ceramic. Chip-to-package interconnection is typically achieved by one of three techniques: wire bonding, tape automated bonding, and solder ball flip chip. Wire bonding is the most widely used first level interconnect; it uses ultrasonic energy to mechanically bond very thin wires from metallized terminal pads along the periphery of the integrated circuit chip to corresponding bond pads on the substrate surface.

Another important role is the polymer as a key building block for all WLPs and related technologies such as IPD (integrated passive devices) and 3D-SiP (system in package). Several different types of photosensitive polymeric materials are available for integration, such as: polyimide (PI), Polybenzoxazole (PBO), benzocyclobutene (BCB), silicone, acrylate, and epoxy.

Polymeric coatings such as polyurethanes, acrylics, epoxies, and silicones have been used for over 40 years to protect Printed Wiring Boards (PWBs) from moisture, handling, and environmental influences. Special semiconductor grade polymers for the passivation layer of the chip have been developed. Especially for epoxy resins, multiple distillation procedures were introduced to remove sodium and chloride ions as by-products in standard epoxy synthesis. Polyimide becomes the standard passivation layer for memory chips and other devices, which requires surface protection for handling and testing processes. Photosensitive resins have been developed to reduce processing costs.

Dry etching requires a masking process using a hard mask, which is a sputtered and structured metal layer, or a thick photoresist coating. The in-depth characterization of materials prevalent in the 1960 s to the 1990 s has slowed significantly due to cost-effective procedures. Furthermore, polymer products are not always sustainable due to a combination of coalescence, segregation and low economic profit. In contrast, polymer materials have become more important with the introduction of new packaging concepts for ICs, such as WLP, SiP and 3-D integration.

There is a wide range of material classes that can be used as polymer dielectric materials for WLPs: polyimide, polybenzoOxazoles, benzocyclobutenes, epoxies, siloxanes, acrylates, nano-filled phenolics, siloxanes, fluorinatedPolymers and polynorbornenes. And M.An extensive review of photosensitizing formulations is given in 2010Electronic Components and technology conference, 769-776.

polyimide-ODA is the first member of a new series of high performance polymers based on alternating aromatic carbocyclic and heterocyclic rings developed by Du Pont:

polyimides are very unique due to their extremely high decomposition temperatures (up to 400 ℃ and above). In addition, its mechanical properties ensure high flexibility (elongation at break up to 100%) and very high tensile strength in excess of 200 MPa. PI remains the most commonly used polymer for IC passivation.

By polybenzo

Oxazoles (PBO) effect modification of the negative-sensitive polymer PI, which is sometimes also referred to as positive-sensitive PI:

the polymer film may be developed after exposure using an aqueous developer.

Siloxanes are polymers with a backbone of Si-O-groups. So-called BCB (benzocyclobutene) is an example of a siloxane-polymer radical additionally having a vinyl group and a benzocyclobutene ring system:

the main advantage is a polymerization reaction with high atom economy (diels-alder reaction) since no by-products are present. Such highly crosslinked thermoset polymers have excellent electrical properties, but are very brittle, with low elongation at break values (8%) and low tensile strengths of 87 MPa.

Epoxy polymers are the basis for most PWBs. The main advantage is that their low curing temperatures are suitable for temperature sensitive devices. Important examples are epoxy resins based on Novolak:

epoxy and acrylate polymers are also available as dry film materials. All other dielectrics must be deposited by spin coating or spray coating.

A more recent development is polynorbornene, which is a bridged cyclic hydrocarbon that is polymerized by ring opening metathesis polymerization or vinyl addition polymerization:

the processing of all liquid type photosensitive film polymers is very similar: coating (mainly spin coating), exposure (UV), post-exposure baking (not all polymers), development, post-exposure baking and curing.

The requirements for selecting a given polymer are quite extensive: high decomposition or glass transition temperatures for high temperature processes in packaging, such as solder reflow, high adhesion, high mechanical and chemical strength, excellent electrical properties, low water absorption, photosensitivity and high yield manufacturability. For these reasons, thermosets are commonly used in packaging applications. They are produced and used as prepolymers, have a molecular weight of several 100000g/mol and are dissolved in organic solvents. This solution is commonly referred to as a precursor and is ready for a spin-coating process. Final polymerization is performed on the wafer by thermal curing.

However, the polymers known from the prior art show the following disadvantages:

polyimide and polybenzene

Azole generally requires very high processing temperatures, which increases the risk of deflection (warping), especially in multilayer redistribution layers (RDL). In addition to this, polyimide exhibits high water absorption, which is a problem of reliability of devices.

Benzocyclobutene derivatives as well as polynorbornene exhibit very low dielectric constants, but this advantage is impaired by very poor adhesion to metals.

Photolithography method

Photolithography has long been a key patterning technique for the construction of inorganic and organic materials used in advanced packaging applications such as flip chip die bumping, gold plating, solder bumping, copper pillar techniques, and redistribution layers. Photolithography is a key manufacturing process and cost factor; in today's industrial lithography applications, careful selection of the correct exposure scheme is critical to achieving the best possible cost structure.

Current driving forces and trends in the semiconductor industry clearly indicate that performance improvements in microelectronic devices are needed to meet future end-user demands. For example, consumer electronics like tablets and smart phones are becoming thinner and smaller while achieving higher computing power, increased data storage and improved communication capabilities. Furthermore, cost considerations are becoming increasingly important in the competitive environment of all parties in the supply chain from chip manufacturers, foundries, assembly and test vendors to device manufacturers. Accordingly, the industry strives to find innovative approaches to reduce manufacturing costs while achieving technologies that meet challenging technical requirements.

Photolithography has been and remains the basic process used in the manufacture and packaging of microelectronic devices for decades. A key component of any lithographic process is an exposure tool that uses light in the ultraviolet wavelength range to pattern a photoresist or polymer. The exposure tool must be able to accurately produce the desired features and align them with previously fabricated structures in the underlying layer. There are currently several types of exposure techniques: proximity or contact printing, laser direct imaging, and projection lithography. The respective tool sets differ in technical capabilities (optical resolution, overlay performance and goodput) and in costs associated with the exposure process. (seeThe methods of the present invention, H.Hichri et al,Micro Tec Photonic System Inc.,Corona,CA,USA)。

object of the Invention

Accordingly, it is an object of the present invention to overcome the disadvantages of the prior art and to provide a new class of polymers which can be used as dielectric materials in passivation layers of encapsulated electronic devices, exhibit excellent film forming ability, are easy to process with conventional solvents, and excellent mechanical properties such as good elongation at break and good tensile strength properties, and have a low dielectric constant and a low Coefficient of Thermal Expansion (CTE).

Furthermore, it is an object of the present invention to provide a novel polymer which is photostructurable and is particularly suitable for various applications in electronic packaging, such as passivation and die attach of conductive or semiconductive components, and as a main component in the preparation of substrates for printed circuit boards.

It is another object of the present invention to provide a polymerizable compound as a monomer, from which a novel polymer is prepared. Further, it is an object of the present invention to provide a method for forming the novel polymer using a polymerizable compound. Finally, it is an object of the present invention to provide an electronic device comprising said polymer as a dielectric material, a manufacturing method for preparing an encapsulated microelectronic structure and a microelectronic device comprising said encapsulated microelectronic structure obtainable by said manufacturing method.

Disclosure of Invention

The inventors have surprisingly found that the above object is achieved by a polymer comprising repeating units derived from a specific polymerizable compound, preferably a polymerizable di-reactive mesogenic compound.

The polymerizable compound is represented by formula (1):

P¹-Sp¹-(MG-Sp¹)_m-P¹formula (1)

Wherein:

m is an integer of 1 to 60, preferably 1 to 50, more preferably 2 to 30, and most preferably 3 to 20;

P¹represents a polymerizable group (P);

Sp¹in each case representing a spacer group (Sp) or a single bond;

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

-(A²¹-Z²¹)_k-A²²-(Z²²-A²³)_l-formula (2)

Wherein:

A²¹to A²³Independently and independently for each occurrence, an aryl, heteroaryl, heterocyclyl, alicyclic group or cyclic imide group, which is optionally substituted by one or more identical or different groups L;

Z²¹and Z²²Independently and independently of each other at each occurrence-O-, -S-, -CO-, -COO-, -OCO-, -S-CO-, -CO-S-, -O-COO-, -CO-NR⁰¹-、-NR⁰¹-CO-、-NR⁰¹-CO-NR⁰²、-NR⁰¹-CO-O-、-O-CO-NR⁰¹-、-OCH₂-、-CH₂O-、-SCH₂-、-CH₂S-、-CF₂O-、-OCF₂-、-CF₂S-、-SCF₂-、-CH₂CH₂-、-(CH₂)₄-、-CF₂CH₂-、-CH₂CF₂-、-CF₂CF₂-、-CH＝N-、-N＝CH-、-N＝N-、-CH＝CR⁰¹-、-CY⁰¹＝CY⁰²-, -C.ident.C-, -CH-COO-, -OCO-CH-or a single bond;

R⁰¹and R⁰²Each independently of the other represents H or an alkyl group having 1 to 12 carbon atoms;

l is F, Cl, Br, I, -CN, -NO₂、-NCO、-NCS、-OCN、-SCN、-C(＝O)NR^xxR^yy、-C(＝O)OR^xx、-C(＝O)R^xx、-NR^xxR^yy、-OH、-SF₅Or a linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radical having 1 to 20C atoms, preferably 1 to 12C atoms, of which one or moreOptionally one H atom is replaced by F or Cl, preferably F, -CN or a linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 6C atoms;

R^xxand R^yyIndependently of one another, H or an alkyl radical having 1 to 12 carbon atoms;

Y⁰¹and Y⁰²Each independently of the others represents H, alkyl having 1 to 12 carbon atoms, aryl, F, Cl or CN; and

k and l are each independently 0,1, 2,3 or 4, preferably 0,1 or 2, most preferably 1.

The polymerizable compounds are useful as monomeric compounds to form a new class of polymers. The novel polymers are prepared by the following process, which also forms part of the present invention:

a method of forming a polymer, wherein the method comprises the steps of:

(i) providing a polymerizable starting material comprising one or more polymerizable compounds according to the present invention; and

(ii) polymerizing the polymerizable starting material.

Also, a polymer is provided, which is obtainable or obtained by the above-described method of forming a polymer.

In addition, an electronic device comprising the polymer according to the invention is provided.

Finally, a manufacturing method for preparing an encapsulated microelectronic structure is provided, wherein a substrate is provided with a coating comprising one or more polymerized liquid crystal monomers, wherein the method comprises the steps of:

(1) applying a polymerizable composition comprising one or more polymerizable compounds according to the present invention to a surface of a substrate; and

(2) curing the polymerizable composition to form a dielectric layer.

There is also provided a microelectronic device comprising a packaged microelectronic structure obtainable or obtained by the manufacturing method according to the invention.

Preferred embodiments of the invention will be described hereinafter and in the dependent claims.

Brief Description of Drawings

The present application does not contain any drawings.

Detailed Description

Definition of

The terms "liquid crystal", "mesogenic (mesogenic) compound" or "mesogenic (mesogenic) compound" (also simply referred to as "mesogen") refer to a compound that may be present as an intermediate phase or especially as a liquid crystal phase under suitable conditions of temperature, pressure and concentration. The non-amphiphilic mesogenic compound comprises for example one or more rod-like, banana-like or disc-like mesogenic groups.

The term "rod-like" refers to a compound or group in the shape of a rod or plate/lath. The term "banana-shaped" refers to a curved group in which two generally rod-shaped curved groups are joined in a non-collinear manner by a semi-rigid group. The term "disk-like" refers to a compound or group that is disk-shaped or sheet-shaped.

The term "mesogenic group" or its abbreviation "MG" refers to a group that has the ability to induce Liquid Crystal (LC) phase behavior. Mesogenic groups, especially those that are not amphiphilic, are usually rod-shaped or disk-shaped. The compounds comprising mesogenic groups do not necessarily have to exhibit an LC phase per se. They may also exhibit LC phase behavior only in mixtures with other compounds, or when mesogenic compounds or mixtures thereof are polymerized. For simplicity, the term "liquid crystal" is used hereinafter for mesogenic and LC materials.

The rod-like mesogenic compounds typically comprise rod-like, i.e. rod-like or lath-like mesogenic groups consisting of one or more aromatic or cycloaliphatic groups connected to each other directly or via 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 typically selected from e.g. carbon-or hydrocarbon-based, polar groups such as halogen, nitro, hydroxyl, etc. or polymerizable groups.

Discotic mesogenic compounds generally comprise discotic, i.e. relatively flat discotic or platy mesogenic groups, which mesogenic groups consist for example of one or more fused aromatic or alicyclic groups such as triphenylene, and optionally comprise one or more terminal groups attached to the mesogenic group and selected from the above mentioned terminal groups and pendant groups.

The term "reactive mesogen" or its abbreviation "RM" refers to a polymerizable mesogen or liquid crystal compound, which is preferably a monomeric or oligomeric compound. Polymerizable compounds having one polymerizable group are also referred to as "mono-reactive" compounds, compounds having two polymerizable groups are referred to as "di-reactive" compounds, and compounds having more than two polymerizable groups are referred to as "multi-reactive" compounds. Compounds without polymerizable groups are also referred to as "non-reactive" compounds.

The term "spacer" or "spacer group", hereinafter also referred to as "Sp", is known to the person skilled in the art and is described in the literature. Unless otherwise indicated, the terms "spacer" or "spacer group" above and below denote a flexible organic group that links a mesogenic group and a polymerizable group in a polymerizable mesogenic compound ("RM").

The term "polymer" includes, but is not limited to, homopolymers, copolymers, such as for example, block, random and alternating copolymers, terpolymers, tetrapolymers, etc., and blends and modifications thereof. Also, unless otherwise specifically limited, 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 molecule of high relative molecular mass whose structure essentially comprises multiple repeating units (i.e., repeat units) that are actually or conceptually derived from molecules of low relative mass (i.e., monomers). In the context of the present invention, a polymer consists of more than 60 monomers.

The term "oligomer" is a molecular complex consisting of several monomer units, in contrast to polymers, in which the number of monomers is in principle not limited. Dimers, trimers and tetramers are for example oligomers comprising two, three and four monomers, respectively. In the context of the present invention, an oligomer may consist of up to 60 monomers.

The term "monomer" as used herein refers to a molecule capable of undergoing polymerization to contribute a constitutional unit (repeating unit) to the basic structure of a polymer or oligomer.

The term "homopolymer" as used herein represents a polymer derived from one (real, implied or hypothetical) monomer.

The term "copolymer" as used herein generally refers to any polymer derived from more than one monomer, wherein the polymer comprises more than one corresponding repeat unit. In one embodiment, the copolymer is the reaction product of two or more monomers, and thus comprises two or more corresponding repeat units. Preferably, the copolymer comprises two, three, four, five or six repeat units. The copolymers obtained by copolymerization of the three monomer species may also be referred to as terpolymers. The copolymers obtained by copolymerization of the four monomer species may also be referred to as tetrapolymers. The copolymers may be present as block, random and/or alternating copolymers.

As used herein, the term "block copolymer" means a copolymer in which adjacent blocks are compositionally different, i.e., adjacent blocks comprise repeat units derived from different kinds of monomers or repeat units derived from the same kind of monomers but having a different composition or sequence distribution of repeat units.

Furthermore, the term "random copolymer" as used herein refers to a polymer formed from macromolecules in which the probability of finding a given repeat unit at any given site in the chain is independent of the nature of adjacent repeat units. Generally, in random copolymers, the sequence distribution of the repeating units follows Bernoullian statistics.

The term "alternating copolymer" as used herein denotes a copolymer consisting of macromolecules comprising two repeating unit species of alternating sequence.

"electronic packaging" is a major discipline in the field of electronic engineering and includes a wide variety of technologies. It refers to the insertion of discrete components, integrated circuits, and MSI (medium scale integration) and LSI (large scale integration) chips (typically attached to a leadframe by beam leads) into a board through holes in a multilayer circuit board (also referred to as a card) where they are soldered in place. Packaging of electronic systems must consider protection from mechanical damage, cooling, radio frequency noise emissions, protection from electrostatic discharge maintenance, operator convenience, and cost.

The term "microelectronic device" as used herein refers to an electronic device having a very small electronic design and components. Typically, but not always, this means on the order of microns or less. These devices typically comprise one or more microelectronic components made of semiconductor material and interconnected in a package structure to form a microelectronic device. Many electronic components of common electronic design are available in the form of microelectronic equivalents. These include transistors, capacitors, inductors, resistors, diodes, and natural insulators, and conductors can all be found in microelectronic devices. Unique wiring techniques such as wire bonding are also often used in microelectronics due to the unusually small dimensions of components, leads, and pads.

The attachment points (binding sites) of the structural elements proposed in the present patent application may consist ofDenotes structural elements and

indicates the binding site.

Preferred embodiments

Polymerizable compound

The present invention relates to a polymerizable compound represented by the formula (1):

P¹-Sp¹-(MG-Sp¹)_m-P¹formula (1)

Wherein:

m is an integer of 1 to 60.

P¹Represents a polymerizable group (P).

Sp¹Each time representing a spacer (Sp) or a single bond;

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

-(A²¹-Z²¹)_k-A²²-(Z²²-A²³)_l-formula (2)

Wherein:

A²¹to A²³Independently and independently at each occurrence, is aryl, heteroaryl, heterocyclyl, alicyclic or cyclic imide, optionally substituted with one or more identical or different groups L;

Z²¹and Z²²Independently and independently of each other at each occurrence-O-, -S-, -CO-, -COO-, -OCO-, -S-CO-, -CO-S-, -O-COO-, -CO-NR⁰¹-、-NR⁰¹-CO-、-NR⁰¹-CO-NR⁰²、-NR⁰¹-CO-O-、-O-CO-NR⁰¹-、-OCH₂-、-CH₂O-、-SCH₂-、-CH₂S-、-CF₂O-、-OCF₂-、-CF₂S-、-SCF₂-、-CH₂CH₂-、-(CH₂)₄-、-CF₂CH₂-、-CH₂CF₂-、-CF₂CF₂-、-CH＝N-、-N＝CH-、-N＝N-、-CH＝CR⁰¹-、-CY⁰¹＝CY⁰²-, -C.ident.C-, -CH-COO-, -OCO-CH-or a single bond;

R⁰¹and R⁰²Each independently of the other represents H or an alkyl group having 1 to 12 carbon atoms;

l is F, Cl, Br, I, -CN, -NO₂、-NCO、-NCS、-OCN、-SCN、-C(＝O)NR^xxR^yy、-C(＝O)OR^xx、-C(＝O)R^xx、-NR^xxR^yy、-OH、-SF₅Or a linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 20C atoms, preferably 1 to 12C atoms, wherein one or more H atoms are optionally replaced by F or Cl, preferably F, -CN or a linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 6 carbon atoms;

R^xxand R^yyIndependently of one another represent H or have 1 to 12An alkyl group of carbon atoms;

Y⁰¹and Y⁰²Independently of one another, H, alkyl having 1 to 12 carbon atoms, aryl, F, Cl or CN; and

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

The polymerizable compounds according to the invention are preferably polymerizable di-reactive mesogenic compounds.

The polymerizable group P is a group capable of undergoing a polymerization reaction such as radical or ionic chain polymerization, polyaddition or polycondensation, or a group capable of undergoing a polymerization-like reaction such as addition or condensation on the polymer backbone.

The index m is preferably from 1 to 50. More preferably, the index m is from 2 to 30, most preferably from 3 to 20.

Preferably, Z²¹And Z²²Independently and independently at each occurrence-COO-, -OCO-, -CO-O-, -O-CO-, -OCH₂-、-CH₂O-、-CH₂CH₂-、-(CH₂)₄-、-CF₂CH₂-、-CH₂CF₂-、-CF₂CF₂-, -C.ident.C-, -CH-COO-, -OCO-CH or a single bond.

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

Preferred polymerizable groups P are selected from groups comprising a C ═ C double bond or a C ≡ C triple bond, and groups suitable for polymerization by a ring-opening reaction, for example, oxetanyl or epoxy groups.

More preferably, the polymerizable group P is selected from CH₂＝CW¹-COO-，CH₂＝CW¹-CO-，

CH₂＝CW²-(O)_k3-、CW¹ ₂＝CH-CO-(O)_k3-、CW¹ ₂＝CH-CO-NH-、CH₂＝CW¹-CO-NH-、CH₃-CH＝CH-O-、(CH₂＝CH)₂CH-OCO-、(CH₂＝CH-CH₂)₂CH-OCO-、(CH₂＝CH)₂CH-O-、(CH₂＝CH-CH₂)₂N-、(CH₂＝CH-CH₂)₂N-CO-、CH₂＝CW¹-CO-NH-、CH₂＝CH-(COO)_k1-Phe-(O)_k2-、CH₂＝CH-(CO)_k1-Phe-(O)_k2-and Phe-CH ═ CH-,

wherein:

W¹represents H, F, Cl, CN, CF₃Phenyl or alkyl having 1 to 5 carbon atoms, more preferably H, F, Cl or CH₃；

W²Represents H or an alkyl group having 1 to 5 carbon atoms, more preferably H, methyl, ethyl or n-propyl;

W³and W⁴Independently of one another, H, Cl or an alkyl radical having 1 to 5 carbon atoms;

phe denotes 1, 4-phenylene which is optionally substituted by one or more radicals L as defined above but is different from P-Sp, preferred substituents L being F, Cl, CN, NO₂、CH₃、C₂H₅、OCH₃、OC₂H₅、COCH₃、COC₂H₅、COOCH₃、COOC₂H₅、CF₃、OCF₃、OCHF₂、OC₂F₅And a phenyl group; and

k₁、k₂and k₃Independently of one another, 0 or 1, k₃Preferably represents 1; and

k₄is an integer from 1 to 10.

The most preferred polymerizable groups P are vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane, epoxy, maleimide, 3-methylmaleimide, 3-ethylmaleimide, 3-propylmaleimide, 3, 4-dimethylmaleimide, 3-methyl-4-ethylmaleimide, 3-methyl-4-propylmaleimide, 3, 4-diethylmaleimide, 3-ethyl-4-propylmaleimide and 3, 4-dipropylmaleimide, most preferred are acrylate, methacrylate, maleimide and 3, 4-dimethylmaleimide.

Preferred spacer groups Sp are selected from the formula Sp '-X', such that the group "P-Sp-" corresponds to the formula "P-Sp '-X' -", wherein:

sp' represents

(a) Straight-chain or branched alkylene having 1 to 40, preferably 1 to 30, carbon atoms, which is optionally mono-or polysubstituted with F, Cl, Br, I or CN, and wherein, in addition, one or more non-adjacent CH' s₂The radicals may be substituted independently of one another by-O-, -S-, -NH-, -NR-⁰¹-、-SiR⁰¹R⁰²-、-CO-、-COO-、-OCO-、-OCO-O-、-S-CO-、-CO-S-、-NR⁰¹-CO-O-、-O-CO-NR⁰¹-、-NR⁰¹-CO-NR⁰¹-, -CH-or-C.ident.C-in such a way that the O and/or S atoms are not directly connected to one another, or

(b)-Sp^x-G-Sp^y-, in which Sp^xAnd Sp^yIndependently of one another, an alkylene group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, or a single bond; g represents a cycloalkylene group having 3 to 20 carbon atoms, preferably 5 to 12 carbon atoms, optionally mono-or polysubstituted with alkyl groups having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms;

x' represents-O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR⁰¹-、-NR⁰¹-CO-、-NR⁰¹-CO-NR⁰¹-、-OCH₂-、-CH₂O-、-SCH₂-、-CH₂S-、-CF₂O-、-OCF₂-、-CF₂S-、-SCF₂-、-CF₂CH₂-、-CH₂CF₂-、-CF₂CF₂-、-CH＝N-、-N＝C-、-N＝N-、-CH＝CR⁰¹-、-CY⁰¹＝CY⁰²-, -C.ident.C-, -CH-COO-, -OCO-CH-or a single bond, preferably-O-, -S-, -CO-, -COO-, -OCO-, -O-COO-、-CO-NR⁰-、-NR⁰¹-CO-、-NR⁰¹-CO-NR⁰¹-or a single bond;

R⁰¹and R⁰²Independently of one another, H or an alkyl radical having 1 to 12 carbon atoms; and

Y⁰¹and Y⁰²Independently of one another, H, F, Cl or CN.

Preferred radicals Sp' are in each case selected from the group consisting of linear methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene and octadecylene, cyclohexylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, ethylene, propylene and butylenes.

More preferably, the spacer Sp is selected from- (CH)₂)_p1-、-(CH₂CH₂O)_q1-CH₂CH₂-、-CH₂CH₂-S-CH₂CH₂-、-CH₂CH₂-NH-CH₂CH₂-、-(SiR⁰¹R⁰²-O)_p1-、-(CH₂)_p1- (Ring-C)₆H₈R⁰¹R⁰²)-(CH₂)_p1-, and

wherein:

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

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

R⁰¹and R⁰²Each independently of the other represents H or an alkyl group having 1 to 12 carbon atoms.

The most preferred group Sp is- (CH)₂)_p1-、-O-(CH₂)_p1-、-O-(CH₂)_p1-O-、-OCO-(CH₂)_p1-and-OCOO- (CH)₂)_p1-, where p1 is an integer from 1 to 36, preferably from 1 to 12.

In a preferred embodiment of the invention, the radical A²¹-A²³Independently and, in the case of a plurality of occurrences, independently of one another, represent a group selected from the following groups a) to e):

a) trans-1, 4-cyclohexylene, 1, 4-cyclohexenylene and 4,4' -dicyclohexylene, in which one or more non-adjacent CH groups₂The radicals may be replaced by-O-and/or-S-, and one or more H atoms may be replaced by a radical L;

b)1, 4-phenylene, 1, 3-phenylene, 4' -biphenylene, 2, 5-thiophene and 2, 6-dithieno [3,2-b:2',3' -d ] thiophene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by a group L;

c) tetrahydropyran-2, 5-diyl, 1, 3-diylAlk-2, 5-diyl, tetrahydrofuran-2, 5-diyl, cyclobut-1, 3-diyl, piperidine-1, 4-diyl, thiophene-2, 5-diyl and selenophene-2, 5-diyl, which may be substituted by one or more L groups;

d) saturated, partially unsaturated or fully unsaturated and optionally substituted polycyclic radicals having 5 to 20 ring carbon atoms, one or more of which may also be replaced by heteroatoms, preferably from the group consisting of bicyclo [1.1.1] pentane-1, 3-diyl, bicyclo [2.2.2] octane-1, 4-diyl, spiro [3.3] heptane-2, 6-diyl, tricyclo [3.3.1.1] decane-1, 3-diyl,

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, and wherein M represents-O-, -S-, -CH₂-、-CHY⁰³-or-CY⁰³Y⁰⁴-；

Y⁰³、Y⁰⁴Each independently represents the above for R⁰¹、F、Cl、CN、OCF₃Or CF₃One of the meanings given, and preferably H, F, Cl, CN, OCF₃Or CF₃；

W⁵、W⁶Independently of one another represent-CH₂CH₂-、-CH＝CH-、-CH₂-O-、-O-CH₂-、-C(R^cR^d) -or-O-;

R^c，R^dindependently of one another, H or an alkyl radical having 1 to 6 carbon atoms, preferably H, methyl or ethyl; and

R⁰³、R⁰⁴h, F, straight-chain or branched alkyl having 1 to 12 carbon atoms, in which one or more H atoms may be replaced by F;

e) a cyclic imide selected from the group consisting of:

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.

Preferred polymerizable compounds according to formula (1) are:

wherein the radicals and indices have the following meanings:

l is F, Cl, Br, I, -CN, -NO₂、-NCO、-NCS、-OCN、-SCN、-C(＝O)NR^xxR^yy、-C(＝O)OR^xx、-C(＝O)R^xx、-NR^xxR^yy、-OH、-SF₅Or a linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 20C atoms, preferably 1 to 12C atoms, wherein one or more H atoms are optionally replaced by F or Cl, preferably F, -CN or a linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 6C atoms;

R^xxand R^yyIndependently of one another, H or an alkyl radical having 1 to 12 carbon atoms;

r is 0,1, 2,3 or 4;

s is 0,1, 2 or 3;

t is 0,1 or 2;

Z²¹and Z²²Independently and independently at each occurrence of-O-, -S-, -CO-, -COO-, -OCO-, -S-CO-, -CO-S-, -O-COO-, -CO-NR⁰¹-、-NR⁰¹-CO-、-NR⁰¹-CO-NR⁰²、-NR⁰¹-CO-O-、-O-CO-NR⁰¹-、-OCH₂-、-CH₂O-、-SCH₂-、-CH₂S-、-CF₂O-、-OCF₂-、-CF₂S-、-SCF₂-、-CH₂CH₂-、-(CH₂)₄-、-CF₂CH₂-、-CH₂CF₂-、-CF₂CF₂-、-CH＝N-、-N＝CH-、-N＝N-、-CH＝CR⁰¹-、-CY⁰¹＝CY⁰²-, -C.ident.C-, -CH-COO-, -OCO-CH-or a single bond, preferably-COO-, -OCO-, -CO-O-, -O-CO-, -OCH₂-、-CH₂O-、-CH₂CH₂-、-(CH₂)₄-、-CF₂CH₂-、-CH₂CF₂-、-CF₂CF₂-, -C.ident.C-, -CH-COO-, -OCO-CH-or a single bond;

R⁰¹and R⁰²Each independently of the other represents H or an alkyl group having 1 to 12 carbon atoms;

Sp¹in each case denotes a spacer group (Sp) or a single bond as defined above;

P¹represents a polymerizable group (P) as defined above; and

m is an integer of 1 to 60, preferably 1 to 50, more preferably 2 to 30, and most preferably 3 to 20.

More preferred polymerizable compounds according to formula (1) are:

wherein the radicals and indices have one of the meanings defined above.

Particularly preferred polymerizable compounds according to formula (1) are:

wherein the radicals and indices have one of the meanings defined above.

The most preferred polymerizable compounds according to formula (1) are:

wherein

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

m is an integer of 1 to 60, preferably 1 to 50, more preferably 2 to 30, and most preferably 3 to 20.

In the compounds of the formulae M1 to M33 and the corresponding sub-formulae, the cyclic group

Preferably is

Wherein the content of the first and second substances,

l is, independently of one another at each occurrence, F, Cl, Br, I, -CN, -NO₂、-NCO、-NCS、-OCN、-SCN、-C(＝O)NR^xxR^yy、-C(＝O)OR^xx、-C(＝O)R^xx、-NR^xxR^yy、-OH、-SF₅Or a straight-chain or branched alkyl having 1 to 20C atoms, preferably 1 to 12C atomsA group, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, 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 6C atoms; and

R^xxand R^yyDefined according to the definitions given above.

The polymerizable compound represented by formula (1) can be prepared by any standard synthesis. Typically, the compounds are retrosynthetically cleaved into smaller units and are built up from suitable precursor compounds. For this purpose, known standard reactions can be used. It has been shown that the polymerizable group P is attached at a later stage of the synthesis, usually in the last step of the synthesis¹Is particularly advantageous. By doing so, undesired side reactions or premature polymerization of the compounds can be avoided.

For example, if the polymerizable compound contains a polymerizable group P represented by the following formula,

wherein W³And W⁴Each independently of the others H, Cl or an alkyl group having 1 to 5 carbon atoms,

a precursor represented by formula (3):

X-Sp¹-(MG-Sp¹)_m-X formula (3)

And

reacting to form a polymerizable compound represented by formula (1):

P¹-Sp¹-(MG-Sp¹)_m-P¹formula (1)

Wherein X is NH₂；

P¹Is that

And

Sp¹MG and m have one of the above definitions.

The invention also provides a method of forming a polymer comprising monomeric units of one or more polymerizable compounds. The polymer is a dielectric polymer that may be linear or crosslinked.

The method of forming a polymer comprises the steps of:

(i) providing a polymerizable starting material comprising one or more polymerizable compounds according to the present invention; and

(ii) polymerizing the polymerizable starting material.

The polymerizable compound contained in the polymerizable starting material is a polymerizable compound represented by formula (1) and the above definition.

Preferably, the polymerizable starting material provided in step (i) comprises one polymerizable compound according to the invention.

In a preferred embodiment, the polymerizable starting material provided in step (i) comprises one or more further polymerizable compounds which are capable of reacting with the polymerizable compounds according to the invention to form a copolymer.

Preferred further polymerizable compounds are monomers which are capable of reacting with the polymerizable groups P of the polymerizable compounds of the invention to form copolymers. These preferred additional polymerizable compounds are selected from the group consisting of acrylates, epoxides, olefins, vinyl ethers, vinyl esters, polythiols, polyamines, and polymaleimides. With the basic knowledge of chemistry, the skilled person is able to find and select a given polymerizable compound of the invention, suitable other polymerizable compounds being able to react with the first-mentioned compounds to form a copolymer.

Preferred acrylates are acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, methyl cyanoacrylate, ethyl acrylate, ethyl methacrylate, ethyl cyanoacrylate, propyl acrylate, propyl methacrylate, propyl cyanoacrylate, butyl acrylate, butyl methacrylate, butyl cyanoacrylate, pentyl acrylate, pentyl methacrylate, pentyl cyanoacrylate, hexyl acrylate, hexyl methacrylate, hexyl cyanoacrylate, heptyl acrylate, heptyl methacrylate, heptyl cyanoacrylate, octyl acrylate, octyl methacrylate, octyl cyanoacrylate, ethylene glycol dimethacrylate, 2-ethylhexyl acrylate, glycidyl methacrylate, (hydroxyethyl) acrylate, (hydroxyethyl) methacrylate, methyl 2-chloroacrylate and methyl 2-fluoroacrylate.

Preferred epoxides are ethylene oxide, propylene oxide, butylene oxide, pentylene oxide, hexylene oxide, heptylene oxide, octylene oxide, glycidylamide, glycidol, styrene oxide, 3, 4-tetrahydrothiophene-1, 1-dioxide oxide, ethyl 2, 3-epoxypropionate, methyl 2-methylglycinate, methyl glycidyl ether, ethyl glycidyl ether, diglycidyl ether, cyclopentene oxide, cyclohexene oxide, cycloheptene oxide, cyclooctene oxide and stilbene oxide.

Preferred olefins are ethylene, propylene, butene, pentene, hexene, heptene, octene, isoprene styrene and vinyl ethylene.

Preferred vinyl ethers are divinyl ether, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether, heptyl vinyl ether and octyl vinyl ether.

Preferred vinyl esters are vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, vinyl caproate, vinyl heptanoate, vinyl octanoate, vinyl nonanoate, vinyl decanoate, vinyl acrylate, vinyl methacrylate, vinyl benzoate, vinyl 4-tert-butylbenzoate, vinyl cinnamate and vinyl trifluoroacetate.

Preferred polythiols are organosulfur compounds having two or more thiol functional groups. Particularly preferred polythiols are selected from HS- (C)_nH_2n) -SH, wherein n ═ 2 to 20, preferably 2 to 12; c_nH_2n-1(SH)₃Wherein n is 3 to 20, preferably 3 to 12; HS-Ar-SH, whereinAr ═ substituted or unsubstituted C₆-C₂₀An arylene group; and HS- (CH)₂)_m-Ar-(CH₂)_m-SH, wherein Ar ═ substituted or unsubstituted C₆-C₂₀Arylene, and m ═ 1 to 12.

Preferred polyamines are organic amine compounds having two or more amino functional groups. Particularly preferred polyamines are selected from H₂N-(C_nH_2n)-NH₂Wherein n is 2 to 20, preferably 2 to 12; h₂N-(C_nH_2nNH)-NH₂Wherein n is 2 to 20, preferably 2 to 12; c_nH_2n-1(NH₂)₃Wherein n is 3 to 20, preferably 3 to 12; h₂N-Ar-NH₂Wherein Ar is optionally substituted C₆-C₂₀An arylene group; and H₂N-(CH₂)_m-Ar-(CH₂)_m-H₂N, wherein Ar is substituted or unsubstituted C₆-C₂₀Arylene, m ═ 1 to 12.

Preferred polymaleimides are maleimide-terminated polyimides as described in US2008/0075961a1 and US2017/0152418a1, the disclosures of which are incorporated herein by reference. Preferably, the polymaleimide is a bismaleimide selected from compounds represented by the following formula (a) or formula (B):

wherein R is₁And Q₁Independently selected from the group consisting of unsubstituted or substituted aliphatic, cycloaliphatic, alkenyl, aryl, heteroaryl, siloxane, poly (butadiene-co-acrylonitrile), and poly (oxyalkylene) derived structures; x₁To X₄Each independently is H or alkyl having 1 to 6C atoms; and n is 0 to 30;

wherein R is₂And Q₂Independently selected from the group consisting of unsubstituted or substituted estersGroup, alicyclic, alkenyl, aryl, heteroaryl, siloxane, poly (butadiene-co-acrylonitrile), and poly (oxyalkylene) -derived structures; x₅To X₈Each independently is H or alkyl having 1 to 6C atoms; r₃And R₄Each independently is H or CH₃Wherein R is₃And R₄Is at least one of CH₃(ii) a And n is 0 to 30.

In a preferred embodiment, the structure derived from unsubstituted or substituted aliphatic, cycloaliphatic, alkenyl, aryl, heteroaryl, siloxane, poly (butadiene-co-acrylonitrile), and poly (oxyalkylene) is alkyl, alkenyl, alkynyl, hydroxy, oxo, alkoxy, mercapto, cycloalkyl, substituted cycloalkyl, heterocyclyl, substituted heterocyclyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, aryloxy, substituted aryloxy, halogen, haloalkyl, cyano, nitro, nitronyl, amino, amido, -C (O) H, acyl, oxyacyl, carboxyl, carbamate, sulfonyl, sulfonamide, thioacyl, or-C (O) -, -S (O)₂-, -OC (O) -O-, -NA-C (O) -, -NAC (O) -NA-, -OC (O) -NA- (wherein A is H or an alkyl group having 1 to 6 carbon atoms), and preferably has a substituent at one end.

Preferred substituents are alkyl, alkenyl, alkynyl, hydroxy, oxo, alkoxy, mercapto, cycloalkyl, substituted cycloalkyl, heterocyclyl, substituted heterocyclyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, aryloxy, substituted aryloxy, halogen, haloalkyl, cyano, nitro, nitronyl, amino, amido, -C (O) H, acyl, oxyacyl, carboxyl, carbamate, sulfonyl, sulfonamide, sulfuryl, or-C (O) -, -S- (O)₂-, -OC (O) -O-, -NA-C (O) -NAC (O) -, -NAC (O) -NA-, -OC (O) -NA- (wherein A is H or an alkyl group having 1 to 6 carbons), an acyl group, an oxyacyl group, a carboxyl group, a carbamate group, a sulfonyl group, a sulfonamide group or a sulfuryl group.

In a more preferred embodiment, R¹And R²、Q¹And Q²Independently selected from substituted or unsubstituted aliphatic, alicyclic ringsA group of.

Preferred aliphatic radicals are straight-chain or branched C₁-C₅₀Alkylene, more preferably straight or branched C₁-C₃₆An alkylene group.

Preferred cycloaliphatic radicals are aliphatic and cyclic and contain one or more all-carbocyclic rings, which may be substituted or unsubstituted, and which may be optionally fused and/or bridged. Preferred cycloaliphatic radicals have 3 to 72C atoms, more preferably 3 to 36C atoms. Particularly preferred alicyclic groups are represented by-Sp¹-Cy-Sp²-represents wherein Sp¹And Sp²Independently of one another, an alkylene group having 1 to 12C atoms or a single bond; g represents cycloalkylene having 3 to 12 carbon atoms, which is optionally mono-or polysubstituted by alkyl having 1 to 12 carbon atoms.

Preferred alkenyl groups are straight or branched chain hydrocarbyl groups having at least one carbon-carbon double bond and having up to about 100 carbon atoms. More preferred alkenyl group is C₂-C₅₀Alkenylene, most preferably C₂-C₃₆An alkenylene group.

Preferred aromatic groups are arylene groups having 6 to 20C atoms, more preferably 6 to 14C atoms, which may be substituted or unsubstituted.

Heteroaromatic groups are aromatic groups that contain one or more heteroatoms (e.g., N, O, S, etc.) as part of a ring structure. Preferred heteroaromatic groups have 3 to 20C atoms, preferably 3 to 14C atoms, and one or more heteroatoms selected from N, O and/or S, and they may be substituted or unsubstituted.

Preferred siloxane groups are selected from the group consisting of- [ R^aR^bSi-O]_n-R^aR^bSi-, wherein R^aAnd R^bIndependently is H or C₁-C₆Alkyl, and n ═ 1 to 1000, more preferably 1 to 100.

Preferred poly (oxyalkylene) groups are poly (C)₁-C₁₂Alkylene oxide) groups.

Preferably, the molar ratio between the polymerizable compound of the present invention and the other polymerizable compounds in the polymerizable starting material is preferably 0.1:100 to 100: 0.1.

Preferably, the polymerizable starting material provided in step (i) is substantially free of solvent. By substantially free of solvent is meant that the total residual solvent content in the polymerizable starting material does not exceed 10 wt-%, preferably does not exceed 5 wt-%, and more preferably does not exceed 1 wt-%, based on the total weight of the polymerizable compound.

Preferably, in step (ii) the polymerisable starting material is polymerised by free radical polymerisation or ionic polymerisation or by exposure to radiation. Further preferably, the polymerizable starting material contains an initiator for radical polymerization or an initiator for ionic polymerization. Further preferably, the polymerization of the polymerizable compound in step (ii) is carried out at elevated temperature, preferably at a temperature in the range of from 25 to 200 ℃, more preferably at a temperature in the range of from 25 to 150 ℃.

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

Preferred initiators for free-radical polymerization are: tert-amyl peroxybenzoate, 4-azobis (4-cyanovaleric acid), 1 '-azobis (cyclohexanecarbonitrile), 2' -Azobisisobutyronitrile (AIBN), benzoyl peroxide, 2-bis (tert-butylperoxy) butane, 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-bis (tert-butylperoxy) -3,3, 5-trimethylcyclohexane, tert-butyl hydroperoxide, tert-butyl peracetate, tert-butyl peroxide, Tert-butyl peroxybenzoate, tert-butyl peroxyisopropylcarbonate, cumene hydroperoxide, cyclohexanone peroxide, dicumyl peroxide, lauroyl peroxide, 2, 4-pentanedione peroxide, peracetic acid, and potassium persulfate. Typically, such initiators are free radical polymerization initiators that can be thermally activated.

Other preferred initiators for free-radical polymerization are: acetophenone, p-anisoyl, 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-benzodioxol-5-yl) -4, 6-bis (trichloromethyl) -1,3, 5-triazine, 2-benzyl-2- (dimethylamino) -4' -morpholinophenylbutanone, (±) -camphorquinone, 2-chlorothioxanthone, 4,4' -dichlorobenzophenone, 2, 2-diethoxyacetophenone, 2, 2-dimethoxy-2-phenylacetophenone, 2, 4-diethylthioxanth-9-one, diphenyl (2,4, 6-trimethylbenzoyl) phosphine oxide, 1, 4-dibenzyloxybenzene, 2-ethylanthraquinone, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-4 ' - (2-hydroxyethoxy) -2-methylpropiophenone, 2-isopropylthioxanthone, phenyl (2,4, 6-trimethylbenzoyl) lithium phosphinate, 2-methyl-4 ' - (methylthio) -2-morpholinopropiophenone, lithium acetate, sodium, 2-isonitrosopropiophenone, 2-phenyl-2- (p-toluenesulfonyloxy) acetophenone and phenylbis (2,4, 6-trimethylbenzoyl) phosphine oxide. Typically, such initiators are photochemically activatable free radical polymerization initiators.

Preferred ionic polymerization initiators are: lithium alkyl compounds, lithium alkylamine compounds, and pentamethylcyclopentadienyl (Cp) complexes of titanium, zirconium, and hafnium.

Further preferred initiators for the ionic polymerization are: bis (4-tert-butylphenyl) iodonium hexafluorophosphate, bis (4-fluorophenyl) iodonium trifluoromethanesulfonate, cyclopropyldiphenylsulfonium tetrafluoroborate, dimethylphenylsulphonyl sulfonium tetrafluoroborate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroarsenate, diphenyliodonium trifluoromethanesulfonate, 2- (3, 4-dimethoxystyryl) -4, 6-bis (trichloromethyl) -1,3, 5-triazine, 2- [2- (furan-2-yl) vinyl ] -4, 6-bis (trichloromethyl) -1,3, 5-triazine, 4-isopropyl-4' -methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, 2- [2- (5-methylfuran-2-yl) vinyl ] -4, 6-bis (trichloromethyl) -1,3, 5-triazine, 2- (4-methoxyphenyl) -4, 6-bis (trichloromethyl) -1,3, 5-triazine, 2- (4-methoxystyryl) -4, 6-bis (trichloromethyl) -1,3, 5-triazine, (2-methylphenyl) (2,4, 6-trimethylphenyl) iodonium trifluoromethanesulfonate, (3-methylphenyl) (2,4, 6-trimethylphenyl) iodonium trifluoromethanesulfonate, (4-methylphenyl) (2,4, 6-trimethylphenyl) iodonium trifluoromethanesulfonate, 4-nitrophenyldiazonium tetrafluoroborate, (4-nitrophenyl) (phenyl) iodonium trifluoromethanesulfonate, 4-nitrophenyldiazonium tetrafluoroborate, 4-nitrophenyl (phenyl) iodonium trifluoromethanesulfonate, bis (trichloromethyl) -1,3, 5-triazine, Triphenylsulfonium tetrafluoroborate, triphenylsulfonium bromide, tri-p-tolylsulfonium hexafluorophosphate, tri-p-tolylsulfonium trifluoromethanesulfonate, [3- (trifluoromethyl) phenyl ] (2,4, 6-trimethylphenyl) iodonium trifluoromethanesulfonate and [4- (trifluoromethyl) phenyl ] (2,4, 6-trimethylphenyl) iodonium trifluoromethanesulfonate. Typically, such initiators are cationic polymerization initiators that can be activated photochemically.

Further preferred initiators for the ionic polymerization are: acetophenone O-benzoyl oxime, 1, 2-bis (4-methoxyphenyl) -2-oxoethylcyclohexylcarbamate, nifedipine, 2-nitrobenzylcyclohexylcarbamate, 2- (9-oxoxanthen-2-yl) propionic acid, 1, 5, 7-triazabicyclo [4.4.0] dec-5-ene salt, 2- (9-oxoxanthen-2-yl) propionic acid, 1, 5-diazabicyclo [4.3.0] non-5-ene salt and 2- (9-oxoxanthen-2-yl) propionic acid, 1, 8-diazabicyclo [5.4.0] undec-7-ene salt. Typically, such initiators are anionic polymerization initiators, which may be activated photochemically.

Exposure to radiation includes exposure to visible and/or UV light. Preferably, the visible light is electromagnetic radiation having a wavelength of more than 380 to 780nm, more preferably more than 380 to 500 nm. Preferably, the UV light is electromagnetic radiation having a wavelength of 380nm or less, more preferably having a wavelength of 100 nm or less and 380 nm. More preferably, the UV light is selected from the group consisting of UV-A light having a wavelength of 315-380nm, UV-B light having a wavelength of 280-315nm, and UV-C light having a wavelength of 100-280 nm.

As the UV light source, an Hg vapor lamp or a UV laser may be used, as the IR light source, a ceramic emitter or an IR laser diode may be used, and for light in the visible region, a laser diode may be used.

Preferred UV light sources are light sources with the following characteristics: a) single wavelength radiation of maximum < 255nm, such as 254nm and 185nm Hg low-pressure discharge lamps, 193nm ArF excimer lasers and 172nm Xe2 layers, or b) radiation of broad wavelength distribution with a wavelength component < 255m, such as undoped Hg low-pressure discharge lamps.

In a preferred embodiment of the invention, the light source is a xenon flash lamp. Preferably, the xenon flash lamp has a broad emission spectrum, with short wavelength components falling to about 200 nm.

Preferably, the polymerization in step (ii) is carried out for a time ranging from 0.1 to 1 hour, preferably from 0.5 to 1 hour.

Also provided is a polymer obtainable or obtained by the above method of forming a polymer according to the present invention. The polymer is preferably a linear or crosslinked polymer, more preferably a linear polymer.

Also provided is a polymer comprising at least one repeating unit derived from a polymerizable compound of formula (1) as defined above.

More preferably, the polymer contains a repeating unit comprising a structural unit represented by the following formula (4):

[-Sp¹-(MG-Sp¹)_m-]formula (4)

Wherein Sp¹MG and m have one of the above definitions.

In a preferred embodiment, the polymer further comprises further repeating units derived from further polymerizable compounds as defined above.

Preferably, the polymer according to the invention has a molecular weight M of at least 2000g/mol, more preferably at least 4000g/mol, even more preferably at least 5000g/mol, as determined by GPC_w. Preferably, the molecular weight M of the polymer_wLess than 50000 g/mol. More preferably, the molecular weight M of the polymer_wIs 5000-.

Furthermore, an electronic device comprising the polymer according to the invention is provided. For electronic devices, it is preferred that the polymer form a dielectric layer. The dielectric layer serves to electrically isolate one or more electronic components that are part of the electronic device from each other.

Finally, a manufacturing method for preparing an encapsulated microelectronic structure is provided, wherein a substrate is provided with a dielectric coating comprising one or more polymerized liquid crystal monomers, wherein the method comprises the steps of:

(1) applying a polymerizable composition comprising one or more polymerizable compounds according to the present invention to a surface of a substrate; and

(2) curing the polymerizable composition to form a dielectric layer.

Preferably, the polymerizable composition provided in step (1) comprises one polymerizable compound according to the present invention.

In a preferred embodiment, the polymerizable composition provided in step (1) comprises one or more additional polymerizable compounds capable of reacting with the polymerizable compound according to the invention to form a copolymer.

Preferred further polymerizable compounds are monomers which are capable of reacting with the polymerizable groups P of the polymerizable compounds of the invention to form copolymers. These preferred other polymerizable compounds are selected from the group consisting of acrylates, epoxides, olefins, vinyl ethers, vinyl esters, polythiols, polyamines, and polymaleimides. With the basic chemical knowledge, the skilled person is able to find and select suitable further polymerizable compounds for a given polymerizable compound of the invention, which are able to react with the first-mentioned compounds to form copolymers.

Preferred acrylates, epoxides, olefins, vinyl ethers, vinyl esters, polythiols, polyamines, and polymaleimides are the same as described above.

Preferably, the molar ratio between the polymerizable compound of the present invention and the other polymerizable compounds in the polymerizable composition is preferably 0.1:100 to 100: 0.1.

Preferably, the polymerizable composition further comprises one or more inorganic filler materials. Preferred inorganic filler materials are selected from nitrides, titanates, diamond, oxides, sulfides, sulfites, sulfates, silicates and carbides, which may optionally be surface modified with capping agents. More preferably, the filler material is selected from AlN, Al₂O₃、BN、BaTiO₃、B₂O₃、Fe₂O₃、SiO₂、TiO₂、ZrO₂PbS, SiC, diamond and glass particles.

Preferably, the total content of inorganic filler material in the polymerizable composition is in the range of from 0.001 wt% to 90 wt%, more preferably from 0.01 wt% to 70 wt%, and most preferably from 0.01 wt% to 50 wt%, based on the total weight of the polymerizable composition.

Preferably, the polymerizable composition provided in step (1) is substantially free of solvent. By substantially free of solvent is meant that the total residual solvent content of the polymerizable composition does not exceed 10 weight percent, preferably does not exceed 5 weight percent, and more preferably does not exceed 1 weight percent, based on the total weight of the polymerizable compounds.

The method for applying the polymerizable composition in step (1) is not particularly limited. The preferred coating method of step (1) is dispensing, dipping, screen printing, stencil printing, roll coating, spray coating, slot coating, spin coating, gravure printing, flexographic printing or inkjet printing.

The polymerizable compounds of the present invention may be provided in the form of formulations suitable for gravure, flexographic and/or inkjet printing. To prepare such formulations, ink-based formulations known in the art may be used.

Alternatively, the polymerizable compounds of the present invention may be provided in a formulation suitable for use in photolithography. Photolithography allows for the creation of a light pattern by transferring a geometric pattern from a photomask to a photocurable composition using light. Typically, such photocurable compositions include a photochemically activatable polymerization initiator. To prepare such a formulation, a photoresist base formulation known in the art may be used.

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

Preferably, the curing in step (2) is performed by free radical polymerization or ionic polymerization or by exposure to radiation. The preferred curing conditions correspond to the preferred polymerization conditions as given above for the method of forming the polymeric material.

A microelectronic device is also provided that includes an encapsulated microelectronic structure prepared according to the above-described fabrication method.

The invention is further illustrated by the following examples, which are not to be construed as limiting in any way thereafter. Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.