HK1060139A - Compositions and methods for thermosetting molecules in organic compositions - Google Patents

Description

Compositions and methods for thermally curing molecules in organic compositions

This patent application is a continuation of the co-pending US serial No. 09/618,945, filed on 19/6/2000.

Technical Field

The field of the invention is the reduction of the dielectric constant.

Background

As interconnectivity in integrated circuits increases and the size of functional elements decreases, the dielectric constant of the insulating material in the metal conductive lines embedding the integrated circuits becomes an increasingly important factor affecting the performance of the integrated circuits. Insulating materials with low dielectric constants (i.e., below 3.0) are particularly desirable because they generally allow faster signal propagation, reduce capacitive effects and cross-talk between wires, and lower the voltage at which integrated circuits are driven.

Since air has a dielectric constant of about 1.0, the main objective is to reduce the dielectric constant of the insulating material to the theoretical limit of 1, and several methods are known in the art for introducing air into insulating materials to reduce the dielectric constant of these materials. In some methods, air is introduced into the insulation material by creating nano-sized voids in a composition comprising a fully crosslinked thermally stable matrix and a thermally labile (thermally decomposable) moiety, wherein the thermally labile moiety is added to the thermally stable matrix material alone (physical blending process) or built into the matrix material (chemical grafting process). Generally, the matrix material is first crosslinked at a first temperature to obtain a three-dimensional matrix, then the temperature is raised to a second temperature (higher temperature) to thermally decompose the thermally labile moieties, and cured at a third temperature (higher temperature) to anneal and stabilize the desired nanoporous material having voids corresponding in size and location to the size and location of the thermally labile moieties.

Nanoporous materials having ideal dielectric constants of about 2.5 or less than 2.5 can be obtained in both physical blending processes and chemical grafting processes. However, physical blending methods typically have only poor control over pore size and pore distribution, while chemical grafting methods often present significant challenges in the synthesis of and introduction of various reactive groups (e.g., to enable crosslinking, addition of thermally labile groups, etc.) into polymers and prepolymers. Furthermore, the chemistry of both the thermally labile moiety and the thermally stable matrix generally limits the processing temperature to a relatively narrow range, which must be different from the crosslinking (curing) temperature, thermal decomposition temperature, and glass transition temperature, thereby significantly limiting the choice of effective materials.

In other methods, air or other gases (i.e., voids) are introduced into the insulating material by introducing hollow nanoscale spheres in the matrix material, such that the nanoscale spheres act as "void carriers" that may or may not be removed from the matrix material. For example, in U.S. patent 5,458,709 to Kamezaki et al, the inventors teach the use of hollow glass spheres in insulation. However, the distribution of glass spheres is often difficult to control, and as the concentration of glass spheres increases, the dielectric material loses flexibility and other desirable physico-chemical properties. Furthermore, glass spheres are typically larger than 20nm and are therefore not suitable for nanoporous materials where pores smaller than 2nm are required.

To produce pores of significantly smaller size than glass spheres, rotoker et al in U.S. patent 5,744,399 describe the use of fullerenes as interstitial carriers. Fullerenes are forms of carbon containing from 32 atoms to about 960 atoms, which are believed to have a spherical lattice dome structure, many of which are believed to occur naturally. The inventors mix the matrix material with fullerenes and cure the mixture to produce a nanoporous dielectric in which the fullerenes can be removed from the cured matrix. Although the pores obtained in this way are generally very uniform in size, the uniform distribution of the void carriers remains problematic. Moreover, both the methods of Rosaker and Kamezaki require the addition or mixing of a void space carrier with the polymeric material, thereby adding necessary processing steps and costs to the manufacture of nanoporous materials.

Although various methods are known in the art for introducing nanosized voids into low dielectric constant materials, all or almost all of them have drawbacks. Accordingly, there is also a need to provide improved compositions and methods for introducing nanoscale voids in dielectric materials.

Summary of the invention

The present invention relates to a process for producing a low dielectric constant polymer. In one step, a star-shaped thermosetting monomer having a core structure and a plurality of branches is provided, and in a subsequent step, the thermosetting monomer is introduced into a polymer, wherein the introduction into the polymer comprises a reaction of a triple bond located on at least one branch.

In one aspect of the inventive subject matter, the core structure is a cage compound or an aryl group, and the preferred branch is an aryl group, a branched aryl group, or an arylene ether. It is also preferred that, in case the core structure is a cage compound, at least one branch has a triple bond. In case the core structure is an aryl compound, it is preferred that all branches have triple bonds. Particularly desirable core structures include adamantane (adamantane), diamantane (diamantane), phenyl, and polyhexamethylene, and particularly desirable branches include diphenylethynyl, phenylethynyl-phenylethynyl phenyl, p-diphenylethynylphenyl, 1, 2-bis (phenylethynyl) phenyl, and p-diphenylethynylphenyl ether.

In another aspect of the inventive subject matter, the introduction of the thermosetting monomer includes reaction at more than one triple bond, preferably at three triple bonds located at three branches, and more preferably at all triple bonds located at all branches. In a particularly preferred aspect of the inventive subject matter, the introduction is carried out without participation of other molecules and preferably involves a cycloaddition reaction.

While it is generally contemplated to incorporate thermosetting monomers in the backbone of the polymer, other positions, including termini and side chains, are also suitable. Preferred polymers include poly (arylene ether) and polymers comprising or consisting of the desired thermosetting monomer. It is particularly desirable that by increasing the length of the branches of the thermosetting monomer, the monomer will define an increased void volume between the monomers after crosslinking, thereby reducing the density of the crosslinked structure and reducing the dielectric constant of the polymer.

Various objects, features, aspects and advantages of the present invention will become more apparent after reading the following detailed description of preferred embodiments of the invention and the accompanying drawings.

Brief Description of Drawings

Fig. 1A-1C are exemplary structures of star-shaped thermosetting monomers having adamantane (adamantane), diamantane (diamantane), and silicon atoms as cage compounds, respectively.

FIGS. 2A-2B are exemplary structures of star-shaped thermosetting monomers having hexaphenylene as the aryl group.

Fig. 3A-3C are exemplary synthetic routes for star-shaped thermosetting monomers according to the inventive subject matter.

Figure 4 is an exemplary route to the synthesis of substituted adamantanes with aryl branches of varying lengths.

Detailed Description

The term "low dielectric constant polymer" as used herein refers to an organic, organometallic, or inorganic polymer having a dielectric constant of about 3.0 or less. The term "cage compound" as also used herein refers to a molecule in which multiple rings formed by covalently bonded atoms define a volume such that a point located within the volume cannot leave the volume without passing through the rings. For example, adamantane-type structures (including adamantane and diamantane) are considered clathrates. In contrast, ring compounds having a single bridging group, such as norbornane (bicyclo [2.2.1] heptane), are not considered cage compounds because the ring in the single bridged ring compound is not volumetrically defined.

In the method of producing a low dielectric constant polymer,a thermosetting monomer of the general formula shown in structure 1 is provided:

(Structure 1)

Wherein Y is selected from the group consisting of a cage compound and a silicon atom, and R₁、R₂、R₃And R₄Is independently selected from the group consisting of aryl, branched aryl, and arylene ether, and wherein at least one of the aryl, branched aryl, and arylene ether has a triple bond. In another step, a thermosetting monomer is introduced into a polymer to form a low dielectric constant polymer, wherein the introduction into the polymer comprises a chemical reaction of at least one triple bond. The term "aryl" as used herein without further specificity refers to any type of aryl group, which may include, for example, a branched aryl group, or an arylene ether. Exemplary structures of thermosetting monomers including adamantane, diamantane, and silicon atoms are shown in fig. 1A, 1B, and 1C, respectively, where n is an integer between 0 and 5 or more.

In another method of producing a low dielectric constant polymer, a thermosetting monomer having the general formula shown in structure 2 is provided:

(Structure 2)

Wherein Ar is aryl, R'₁-R′₆Is independently selected from the group consisting of aryl, branched aryl, arylene ether, and null, and wherein each of the aryl, branched aryl, and arylene ether has at least one triple bond. In a subsequent step, a thermosetting monomer is introduced into the polymer, thereby forming a low dielectric constant polymer, wherein the introduction into the polymer comprises a chemical reaction of at least one triple bond. Exemplary structures of thermosetting monomers including tetra-and hexa-substituted hexaphenylene groups are shown in fig. 2A and 2B, respectively.

Thermosetting monomers, generally as shown in structures 1 and 2, can be provided by various synthetic routes, with exemplary synthetic strategies for structures 1 and 2 shown in fig. 3A-3C. Fig. 3A depicts a preferred synthetic route to star thermosetting monomers using adamantane as the cage compound, where the bromoarene is phenylethynylated in a palladium-catalyzed Heck reaction. First, adamantane (1) was brominated to Tetrabromoadamantane (TBA) (2) according to the procedure previously described (j.org. chem.45, 5405-. TBA was reacted with bromobenzene as described by Reichert, V.R and Mathias l.j. in Macromolecules, 27, 7015-. The palladium catalyzed Heck reaction can also be used to synthesize star thermosetting monomers having hexaphenylene as the aromatic moiety as shown in fig. 2C and 2D, where tetrabromohexaphenylene and hexabromohexaphenylene are reacted with ethynylaryl groups, respectively, to obtain the desired corresponding star thermosetting monomer.

Alternatively, TBA (see above) can be converted to hydroxyarylated adamantane, which is then converted to a star thermosetting monomer in a nucleophilic aromatic substitution reaction. In fig. 3B, TBA (2) is generated from adamantane (1) as described previously, and further subjected to electrophilic tetra-substitution reaction with phenol to obtain tetra (hydroxyphenyl) adamantane (THPA) (7). Alternatively, TBA can also be reacted with anisole to give tetrakis (4-methoxyphenyl) adamantane (TMPA) (6), which can be further reacted with BBr₃Reacting to obtain THPA (7). THPA can then be reacted with the active fluoroaromatic compound in various nucleophilic aromatic substitution reactions in the presence of potassium carbonate using standard procedures (e.g., Engineering Plastics-A Handbook of Polyarylethers, R.J.Cotter, Gordon and Breach Publishers, ISBN 2-88449-112-0), or THPA can be reacted with 4-halo-4' -fluorotolane (where halo ═ Br or I) in standard aromatic substitution reactions (e.g., Engineering Plastics, supra) to obtain tetrakis [4- (4-halophenylethynylphenoxy) phenyl]Adamantane (8). In an alternative reaction, various alternative reactants may also be usedTo produce a shaped thermoset monomer. Similarly, a nucleophilic aromatic substitution reaction can also be utilized in the synthesis of a star thermoset monomer with a hexaphenylene group as the aromatic moiety as depicted in FIG. 2D, wherein the hexaphenylene group reacts with 4-fluorodiphenylacetylene to form the star thermoset monomer. Alternatively, phloroglucinol can be reacted with 1- (4-fluoro-phenylethynyl-4-phenylethynyl) -4-benzene in standard aromatic substitution reactions to give 1, 3, 5-tris (phenylethynylphenylethynyl-phenoxy) benzene.

In the case where the clathrate compound is a silicon atom, an exemplary preferred synthetic route is depicted in fig. 3C, wherein a bromine (phenylethynyl) aromatic branch (9) is converted to the corresponding lithium (phenylethynyl) aromatic branch (10), which is subsequently reacted with silicon tetrachloride to obtain the desired star-shaped thermosetting monomer having a silicon atom as clathrate compound.

While it is preferred that the cage compound be adamantane or diamantane, in alternative aspects of the inventive subject matter, various cage compounds other than adamantane or diamantane are also contemplated. It should be especially clear that the molecular size and configuration of the cage compounds and the branching R₁-R₄Or R'₁-R′₆The combination of total length of (a) determines the size of the voids (through steric effects) in the final low dielectric constant polymer. Thus, where relatively small clathrate compounds are desired, substitution and derivatization of adamantanes, diamantanes, and relatively small bridged cycloaliphatic and aromatic compounds (typically less than 15 atoms) are contemplated. Conversely, where larger clathrates are desired, larger bridged cycloaliphatic and aromatic compounds (typically more than 15 atoms) and fullerenes are contemplated.

It should furthermore be clear that the contemplated clathrates are not necessarily limited to carbon atoms, but may also include heteroatoms such as N, S, O, P and the like. The heteroatoms can advantageously be introduced into a non-tetragonal bond angle configuration, which in turn can lead to branching R₁-R₄Or R'₁-R′₆Covalently linked at other bond angles. With respect to substituents and derivatizations of contemplated cage compounds, it should be recognized that many substituents and derivatizationsDerivatization is suitable. For example, in the case of a clathrate compound that is relatively hydrophobic, hydrophilic substituents may be introduced to increase solubility in hydrophilic solvents, or vice versa. Alternatively, where polarity is desired, polar side groups may be added to the cage compound. It is further contemplated that suitable substituents may also include thermally labile groups, nucleophilic and electrophilic groups. It should also be clear that functional groups may be used in the cage compound (e.g., to facilitate crosslinking reactions, derivatization reactions, etc.). In the case of derivatization of the cage compounds, it is conceivable in particular for the derivatives to comprise halogenation of the cage compounds, and particularly preferably for the halogen to be fluorine.

In yet another alternative aspect of the inventive subject matter, the cage compound may be replaced with a non-carbon atom having a polygonal, more preferably a tetragonal, configuration. Desirable atoms include silicon atoms, particularly desirable atoms include atoms that exhibit a polygonal ligand configuration and form covalent bonds having oxidation resistance greater than carbon-carbon bonds. In addition, the alternative atoms may also include cationic and anionic species of the particular atom. Suitable atoms are for example Ge and P.

Having a coupling to a branch R 'as shown in Structure 2 in a thermosetting monomer'₁-R′₆In the case of aryl groups of (a), it is preferred that the aryl group comprises a phenyl group, and even more preferred that the aryl group is a phenyl group or a hexaphenylene group. In alternative aspects of the inventive subject matter, it is contemplated that various aryl compounds other than phenyl or hexaphenylene are also suitable, including substituted and unsubstituted bicyclic and polycyclic aromatic compounds. Substituted and unsubstituted bicyclic and polycyclic aromatics are particularly advantageous, with size-increasing thermoset monomers being preferred. For example, naphthalene, phenanthrene and anthracene are especially contemplated where it is desirable that the alternative aryl group have greater extensibility in one dimension than in another. In other cases, where symmetrical stretching of alternative aryl groups is desired, polycyclic aryl groups such as coronenes are contemplated. In particularly preferred aspects, the desired bicyclic and polycyclic aromatic groups have conjugated aromatic systems that may or may not include heteroatoms. For substitution and derivatization of the desired aryl radicals, the use ofThe same considerations apply for the clathrate compound (see above).

For branch R₁-R₄And R'₁-R′₆Preferably, R is₁-R₄Independently selected from aryl, branched aryl and arylene ether, and R'₁-R′₆Independently selected from aryl, branched aryl, arylene ether, and absent. Especially desirable R₁-R₄And R'₁-R′₆The aryl group of (a) includes aryl groups having a diphenylethynyl, phenylethynylphenylethynylethynylphenyl, and p-diphenylethynylphenyl moiety, as well as diphenylethynyl, phenylethynylphenylethynylethynylphenyl, and p-diphenylethynylphenyl moieties. Particularly preferred branched aryl groups include 1, 2-bis (phenylethynyl) phenyl, with particularly desirable arylene ethers including p-diphenylethynylphenyl ether.

In alternative aspects of the inventive subject matter, suitable branches need not be limited to aryl, branched aryl, and arylene ether, so long as the alternative branch R₁-R₄And R'₁-R′₆Including reactive groups, and as long as the introduction of the thermosetting monomer includes a reaction involving the reactive groups. The term "reactive group" as used herein refers to any element or combination of elements that has sufficient reactivity for introducing the monomer into the polymer. For example, the desired branches may be relatively short, no more than 6 atoms, which may or may not be carbon atoms. These short branches are particularly advantageous where it is desired that the size of the voids introduced into the final low dielectric constant polymer must be relatively small. Conversely, where particularly long branches are preferred, the branches may comprise oligomers or polymers having a number of atoms ranging from 7 to 40 and greater. In addition, the length and chemical composition of the branches covalently coupled to contemplated thermosetting monomers can vary within one monomer. For example, a cage compound may have two relatively short branches and two relatively long branches to promote size growth in a particular direction during polymerization. In another example, a cage compound may have two moieties that differ in chemical nature from one anotherTwo branches are branched to facilitate regioselective derivatization reactions.

It should also be clear that while it is preferred that all branches in the thermosetting monomer have at least one reactive group, in alternative aspects not all branches need have a reactive group. For example, a cage compound may have 4 branches, while only 3 or 2 of these branches carry reactive groups. In addition, the aryl group in the thermosetting monomer may have three branches, of which only two or one branch has a reactive group. It is generally assumed that in branch R₁-R₄And R'₁-R′₆The number of reactive groups in each of (a) can vary widely depending on the chemical nature of the branching and the quality of the desired end product. Moreover, it is contemplated that the reactive group may be located on any portion of the branch, including the backbone, side chains, and ends of the branch. It should be especially clear that the number of reactive groups in the thermosetting monomer can be used as a means of controlling the degree of crosslinking. For example, where a relatively low degree of crosslinking is desired, the desired thermosetting monomer may have only one or two reactive groups, which may or may not be located on one branch. On the other hand, where a relatively high degree of crosslinking is desired, the monomer may include three or more reactive groups. Preferred reactive groups include electrophilic and nucleophilic groups, more preferably groups that can participate in cycloaddition reactions, and particularly preferred reactive groups are ethynyl groups.

In addition to the reactive groups in the branches, other groups (including functional groups) may also be introduced on the branches. For example, where it is desired to add specific functional moieties (e.g., thermally labile moieties) after the thermosetting monomer is incorporated into the polymer, these functional moieties may be covalently bonded to the functional group.

Thermosetting monomers can be incorporated into polymers by a number of mechanisms, with the actual incorporation mechanism being largely dependent on the reactive groups involved in the incorporation. Thus, contemplated mechanisms include nucleophilic, electrophilic and aromatic substitution, addition, elimination, radical polymerization and cycloaddition, and particularly preferred introduction is cycloaddition involving at least one ethynyl group located on at least one branch. For example, in a thermosetting monomer having a branch selected from the group consisting of an aryl group, a branched aryl group, and an arylene ether in which at least three of the aryl group, branched aryl group, or arylene ether have a triple bond, the introduction of the monomer into the polymer may include a cycloaddition reaction (i.e., a chemical reaction) of at least three triple bonds. In another example, in a thermosetting monomer in which all of the aryl, branched aryl, and arylene ether branches have one triple bond, incorporation of the monomer into the polymer may include cycloaddition (i.e., chemical reaction) of all triple bonds. In other examples, cycloaddition (e.g., diels-alder reaction) may occur between at least one branched ethynyl group of the thermosetting monomer and a diene group located in the polymer. It is also envisaged that the incorporation of the thermosetting monomer into the polymer takes place without the participation of other molecules (e.g. cross-linking agents), preferably as a cycloaddition reaction between the reactive groups of the thermosetting monomer. However, in an alternative aspect of the inventive subject matter, a crosslinking agent may be used to covalently couple the thermosetting monomer to the polymer. This covalent coupling can thus be carried out between the reactive group and the polymer or between the functional group and the polymer.

The reaction conditions may vary widely depending on the mechanism by which the thermosetting monomer is incorporated into the polymer. For example, where the monomer is introduced by cycloaddition using at least one branched triple bond, it is generally sufficient to heat the thermosetting monomer to about 250 ℃ and maintain that temperature for about 45 minutes. Conversely, where monomers are introduced into the polymer by free radical reaction, room temperature and the addition of a free radical initiator may be appropriate. Preferred methods of introduction are set forth in the examples.

With respect to the location of incorporation of the thermosetting monomer into the polymer, it is contemplated that the thermosetting monomer may be incorporated into the backbone, end or side chain of the polymer. The term "backbone" as used herein refers to a linked chain of atoms or moieties that form a covalent linkage such that removal of any atom or moiety will result in a chain break.

Contemplated polymers include various polymer types such as polyimide, polystyrene, polyamide, and the like. However, it is especially contemplated that the polymer comprises a polyaryl group, more preferably a poly (arylene ether). In an even more preferred aspect, the polymer is at least partially prepared from a thermosetting monomer, and more desirably the polymer is prepared entirely from a thermosetting monomer.

It should be especially appreciated that: (1) the size of the cage compound or aryl group, and (2) a branched R covalently coupled to the cage compound₁-R₄And R'₁-R′₆Will determine the nanoporosity imparted by the steric effect. Thus, in the case where the thermosetting monomer having a cage compound or a silicon atom is part of a low dielectric constant polymer, and in the case of the branch R₁-R₄In the case of a polymer having a total length L and a low dielectric constant having a dielectric constant K, the dielectric constant K will decrease as L increases. Similarly, where the aryl-bearing thermosetting monomer is part of a low dielectric constant polymer, and in branched R'₁-R′₆In the case of a polymer having a total length L and a low dielectric constant having a dielectric constant K, the dielectric constant K will decrease as L increases. Thus, the size of the cage compound, the aryl group, and particularly the size of the branches in the thermosetting monomer can be used to fine tune or adjust the dielectric constant of the low dielectric constant polymer with the thermosetting monomer. It is especially contemplated that by extending the branches in the thermosetting monomer, the dielectric constant may be reduced by an amount of up to 0.2, preferably up to 0.3, more preferably up to 0.4 and most preferably up to 0.5 dielectric constant units.

In a particularly contemplated branch extension method depicted in fig. 4, wherein AD represents an adamantane or diamantane group. Phenylacetylene is the starting molecule for reaction with TBA (see above) (a1) to obtain tetrakis (monobhenylethynyl) -adamantane. Alternatively, phenylacetylene can be converted (B1) to tolanynyl bromide, which is subsequently reacted with trimethylsilylacetylene (C1) to form tolanynyl acetylene. TBA can then be reacted with diphenylethynylacetylene (a2) to form tetrakis (bisdiphenylethynyl) -adamantane. In another extension reaction, tolane is reacted with 1-bromo-4-iodobenzene (B2) to form bis-tolane bromide, which is further converted (C2) to bis-tolane. The bis-diphenylethynylacetylene thus formed can then be reacted with TBA (a3) to yield tetrakis (tris (diphenylethynyl)) -adamantane.

It is particularly contemplated that the thermosetting monomers according to the inventive subject matter may be used in dielectric layers of electronic devices, wherein preferred dielectric layers have a dielectric constant of less than 3, and preferred electronic devices include integrated circuits. Accordingly, contemplated electronic devices may include a dielectric layer, wherein the dielectric layer includes a polymer prepared from a thermosetting monomer having the following structural formula:or

Wherein Y is selected from a cage compound and a silicon atom, Ar is preferably an aryl group, R₁-R₄Is independently selected from aryl, branched aryl and arylene ether, R'₁-R′₆Independently selected from the group consisting of aryl, branched aryl, arylene ether, and null, wherein at least one of the aryl, branched aryl, and arylene ether has a triple bond.

Examples

The following examples describe exemplary syntheses of thermoset molecules, and the preparation of low dielectric constant films, according to the inventive subject matter.

Example 1

Synthesis of Tetrabromoadamantane (TBA)

Adamantane was brominated to TBA following the procedure described previously in J.org.chem.45, 5405-5408(1980) for Sollot, G.P. and Gilbert, E.E.

Tetra (3/4-bromo)Synthesis of phenyl) adamantane (TBPA)

The reaction of TBA with bromobenzene yielded tetrakis (3/4-bromophenyl) adamantane (TBPA) as described by Reichert, V.R. and Mathias L.J. in Macromolecules, 27, 7015-. The reaction results in the formation of various by-products. HPLC-MS analysis showed the yield of desired TBPA to be about 50%, with 40% tetraphenyladamantane tribromide and about 10% tetraphenyladamantane dibromide. However, unexpectedly, when the product mixture encounters fresh reagents and catalyst (bromobenzene and AlCl)₃At 20 ℃ for 1 minute), TBPA was obtained in about 90% yield.

Synthesis of tetra (diphenylethynyl) adamantane (TTA)

TBPA was reacted with phenylacetylene following the general reaction procedure of palladium catalyzed Heck ethynylation to obtain the final product tetrakis (diphenylethynyl) adamantane.

TTA prepared by the method described above was dissolved in cyclohexanone to give a 15-20% by weight solution, of which 5ml were spin coated onto two silicon wafers using standard procedures well known in the art. By heating to a temperature of about 150 ℃ and under N₂Holding for 1 minute, heating to a temperature of about 200 deg.C and under N₂Holding for 1 minute, and heating to a temperature of about 250 deg.C and under N₂The temperature was maintained for 1 minute, and the temperature was raised at 250 ℃ and 5 ℃ K/minute, followed by curing at 400 ℃ for 1 hour, to polymerize TTA on the silicon wafer. The k value was obtained by coating a cured TTA film with a thin film of aluminum, then performing capacitance-voltage measurements at 1MHz and calculating the k value based on the film thickness. The cured TTA film had the following properties: the k-value was 2.65, the refractive index after baking was 1.702, the refractive index after curing was 1.629, the thickness after baking was 8449 angstroms, the thickness after curing was 9052 angstroms, the cured thickness change was 7.1% after baking, and the prepared tape tested for pass.

Example 2Synthesis of p-bromodiphenylacetylene

A500 mL three-necked round bottom flask equipped with an addition funnel and nitrogen inlet was charged with 4-iodobromobenzene (25.01g, 88.37mmol), triethylamine (300mL), bis (triphenylphosphine) palladium [ II ] chloride (0.82g) and copper [ I ] iodide (0.54 g). Then, a solution of phenylacetylene (9.025g, 88.37mmol) in triethylamine (50mL) was added slowly and the temperature of the solution was maintained below 35 ℃ with stirring. After the addition was complete, the mixture was stirred for an additional 4 hours. The solvent was evaporated on a rotary evaporator and the residue was added to 200mL of water. The product was extracted with dichloromethane (2X 150 mL). The organic layers were combined and the solvent was removed on a rotary evaporator. The residue was washed with 80mL of hexane and filtered. TLC and HPLC showed pure product (yield, 19.5g, 86%). Additional purification was performed by short silica column chromatography (eluent is a 1: 2 mixture of toluene and hexane). A white crystalline solid was obtained after removal of the solvent. The purity of the product was characterized by GC/MS in acetone solution, additionally by proton NMR.

Synthesis of p-ethynyl diphenylacetylene

The synthesis of p-ethynyl tolane from p-bromotolane is carried out in two steps. In a first step, trimethylsilylacetylation of p-bromodiphenylacetylene is carried out and, in a second step, the reaction product of the first step is converted into the final product.

Step 1 (trimethylsilylacetylation of 4-bromodiphenylacetylene): 4-bromodiphenylacetylene (10.285g, 40.0mMol), ethynyltrimethylsilane (5.894g, 60.0mMol), 0.505g (0.73mMol) of dichlorobis (triphenylphosphine) palladium [ II ] II]Catalyst, 40mL of anhydrous triethylamine, 0.214g (1.12mMol) of copper iodide [ I]And 0.378g (1.44mMol) of triphenylphosphine were charged into N equipped with an overhead mechanical stirrer, condenser and internal heating mantle₂Purged 5L four-necked round bottom flask. Will be mixed withThe mixture was heated to gentle reflux (about 88 ℃) and held at reflux for 1.5 hours. The reaction mixture turned into a thick black paste and was cooled. Thin layer chromatography analysis showed complete conversion of the starting material, 4-bromodiphenylacetylene, to a single product. The solid was filtered, washed with 50mL of triethylamine, mixed with 400mL of water and stirred for 30 minutes. The solid was filtered and washed with 40mL of methanol. The crude solid was recrystallized from 500mL of methanol. After standing, bright silver crystals settled out. It was separated by filtration and washed with 2X 50mL of methanol. 4.662g (42.5% yield) was recovered.

Step 2 (conversion of 4- (trimethylsilyl) ethynyl tolane to 4-ethynyl tolane): to a 1L three-necked round bottom flask equipped with a nitrogen inlet and an overhead mechanical stirrer were added 800mL of anhydrous methanol, 12.68g (46.2mMol) of 4- (trimethylsilyl) ethynyltolane and 1.12g of anhydrous potassium carbonate. The mixture was heated to 50 ℃. Stirring was continued until no starting material was detected by HPLC analysis (approximately 3 hours). The reaction mixture was cooled. The crude solid was stirred in 40mL of dichloromethane for 30 minutes and filtered. HPLC analysis of the filtered suspended solid showed the majority of impurities. The dichloromethane filtrate was dried and evaporated to yield 8.75g of a solid. After further drying in the oven, the final weight was 8.67g, which represents a yield of 92.8%.

Synthesis of tetra (bis-diphenylethynyl) adamantane (TBTA)

TBPA (see above) was reacted with 4-ethynyltolane according to the general procedure for palladium catalyzed Heck ethynylation to obtain the final product tetrakis (bistolynyl) adamantane (TBTA).

TBTA thus prepared was dissolved in cyclohexanone to give a 10% by weight solution, of which 5ml was spin coated onto two silicon wafers using standard procedures well known in the art. TBTA was polymerized on silicon wafers by heating to a temperature of about 300 c and curing at a temperature of 400 c for 1 hour. The K value was found to be 2.57. It should be especially appreciated that when this k value is compared to the k value of TTA (which is a structural analog of TBTA with shorter branch lengths), the k value of TTA is about 2.60 higher. Thus, experiments have shown that the expected decrease in k-value is due to an increase in the length of the branches extending from the cage compound.

Thus, specific embodiments and applications of the compositions and methods for producing low dielectric constant polymers have been disclosed. However, it will be apparent to those skilled in the art that many more variations than those described above are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms "comprises" and "comprising," when used in a non-exclusive manner, indicate that the stated elements, components or steps may be present, utilized or combined with other elements, components or steps that are not expressly stated.

Claims (30)

1. A method of producing a low dielectric constant polymer comprising the steps of: providing a thermosetting monomer having the structure:

wherein Y is selected from the group consisting of a cage compound and a silicon atom, and R₁、R₂、R₃And R₄Independently selected from the group consisting of aryl, branched aryl, and arylene ether, and wherein at least one of the aryl, branched aryl, and arylene ether has a triple bond; and

incorporating the thermosetting monomer into a polymer to form a low dielectric constant polymer, wherein the incorporation into the polymer comprises a chemical reaction of the triple bond.

2. The method of claim 1, wherein Y is selected from the group consisting of adamantane and diamantane.

3. The method of claim 1, wherein the aryl group comprises a moiety selected from the group consisting of diphenylethynyl, phenylethynylphenylethynylphenyl, and p-diphenylethynylphenyl.

4. The method of claim 1, wherein the branched aryl group comprises a1, 2-bis (phenylethynyl) phenyl group.

5. The method of claim 1, wherein the arylene ether comprises p-diphenylethynylphenyl ether.

6. The method of claim 1, wherein at least three of the aryl group, the branched aryl group, and the arylene ether have triple bonds, and wherein introducing into the polymer comprises a chemical reaction of the at least three triple bonds.

7. The method of claim 1, wherein all of the aryl groups, branched aryl groups, and arylene ether have triple bonds, and wherein introducing into the polymer comprises a chemical reaction of all of the triple bonds.

8. The method of claim 1, wherein R₁、R₂、R₃And R₄Has a total length L, and the low dielectric constant polymer has a dielectric constant K, and wherein K decreases as L increases.

9. The method of claim 1, wherein the polymer comprises a poly (arylene ether).

10. The method of claim 1, wherein the step of incorporating the thermosetting monomer into the polymer is performed without the participation of other molecules.

11. A method of producing a low dielectric constant polymer comprising the steps of:

providing a thermosetting monomer having the structure:

wherein Ar is aryl, R'₁、R′₂、R′₃、R′₄、R′₅And R'₆Independently selected from the group consisting of aryl, branched aryl, arylene ether, and null, and wherein each of the aryl, branched aryl, and arylene ether has at least one triple bond; and

incorporating the thermosetting monomer into a polymer to form a low dielectric constant polymer, wherein the incorporation into the polymer comprises a chemical reaction of the at least one triple bond.

12. The method of claim 11, wherein the aryl group comprises a phenyl group.

13. The method of claim 12, wherein Ar is selected from the group consisting of phenyl and hexaphenylene.

14. The process of claim 11, wherein R'₁、R′₂、R′₃、R′₄、R′₅And R'₆Has a total length L, and the low dielectric constant polymer has a dielectric constant K, and wherein K decreases as L increases.

15. The method of claim 11, wherein the step of incorporating the thermosetting monomer into the polymer is performed without the participation of other molecules.

16. The method of claim, wherein the polymer comprises a poly (arylene ether).

17. A thermosetting monomer having the structure:

wherein Y is selected from the group consisting of a cage compound and a silicon atom, and R₁、R₂、R₃And R₄Is independently selected from the group consisting of aryl, branched aryl, and arylene ether, and wherein at least one of the aryl, branched aryl, and arylene ether has a triple bond.

18. A thermosetting monomer having the structure:

wherein Ar is aryl, and R'₁、R′₂、R′₃、R′₄、R′₅And R'₆Is independently selected from the group consisting of aryl, branched aryl, arylene ether, and null, and wherein each of the aryl, branched aryl, and arylene ether has at least one triple bond.

19. A thermosetting monomer having a structure according to formula TM-1:wherein n is 1-3.

20. A thermosetting monomer having a structure according to formula TM-2:wherein n is 1-3.

21. A thermosetting monomer having a structure according to formula TM-3:

22. an electronic device comprising a dielectric layer comprising a polymer prepared from at least one thermosetting monomer selected from the group consisting of:

wherein Y is selected from the group consisting of a cage compound and a silicon atom, and R₁、R₂、R₃And R₄Independently selected from the group consisting of aryl, branched aryl, and arylene ether, and wherein at least one of the aryl, branched aryl, and arylene ether has a triple bond;

wherein Ar is aryl, and R'₁、R′₂、R′₃、R′₄、R′₅And R'₆Independently selected from the group consisting of aryl, branched aryl, arylene ether, and null, and wherein each of the aryl, branched aryl, and arylene ether has at least one triple bond;and;

23. a dielectric material comprising a polymer prepared from at least one thermosetting monomer selected from the group consisting of:

wherein Y is selected from the group consisting of a cage compound and a silicon atom, and R₁、R₂、R₃And R₄Independently selected from the group consisting of aryl, branched aryl, and arylene ether, and wherein at least one of the aryl, branched aryl, and arylene ether has a triple bond;

wherein Ar is aryl, and R'₁、R′₂、R′₃、R′₄、R′₅And R'₆Independently selected from the group consisting of aryl, branched aryl, arylene ether, and null, and wherein each of the aryl, branched aryl, and arylene ether has at least one triple bond;and;

24. the dielectric material of claim 23, wherein the polymer is prepared from at least one thermosetting monomer selected from the group consisting of:

wherein Y is selected from the group consisting of a cage compound and a silicon atom, and R₁、R₂、R₃And R₄Independently selected from the group consisting of aryl, branched aryl, and arylene ether, and wherein at least one of the aryl, branched aryl, and arylene ether has a triple bond;

25. a layer comprising the dielectric material of claim 23.

26. A layer comprising the dielectric material of claim 24.

27. A film comprising the dielectric material of claim 23.

28. A film formed from the dielectric material of claim 24.

29. The film of claim 27 wherein the dielectric constant is less than 3.

30. The film of claim 28 wherein the dielectric constant is less than 3.