Preparation method and application of linear benzocyclobutene monomer containing rigid ladder structure

Abstract

The application discloses a preparation method and application of a linear rigid ladder structure-containing benzocyclobutene monomer. The linear rigid ladder structure-containing benzocyclobutene monomer provided by the application has a structure shown in formula I. The linear rigid ladder structure-containing benzocyclobutene curing product provided by the application shows superior dielectric performance (D k <2.46, D f =2.50x10 ‑3 ), high thermal stability (temperature of 5% thermal weight loss is greater than 440 DEG C) and good dimensional stability (49 ppm / DEG C). Research results show that the introduction of low-polarizability all-carbon hydrogen and rigid norbornene structure can well reduce the dielectric constant and dielectric loss of the material, while maintaining good thermodynamic stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of high-performance electronic packaging resins, and particularly relates to a preparation method of a linear rigid ladder structure benzocyclobutene monomer and application thereof. BACKGROUND

[0002] With the rapid development of 5G communication networks, the demand for high-performance, low dielectric constant (k < 2.5) and low dielectric loss interlayer dielectric materials in high-speed communication equipment is increasing. To meet the requirements of terminal electronic devices on dielectric properties in future high-frequency high-speed signal transmission networks, the preparation of polymer materials with low dielectric constant and low dielectric loss has become a research hotspot in this field. Traditionally, interlayer dielectric materials usually use inorganic materials. However, compared with inorganic low dielectric materials, organic polymer materials usually have lower dielectric constant, while having excellent mechanical properties and processing performance.

[0003] Benzocyclobutene (BCB) monomer has the thermodynamic stability of aromatic compounds and the kinetic reactivity of stress rings. When heated to 200℃, the four-membered ring undergoes ring-opening to form a highly active polymerizable intermediate. This intermediate not only can undergo Diels-Alder addition reaction with a dienophile monomer, but also can generate a polymer through its own reaction. Its unique thermally induced ring-opening polymerization does not require the addition of catalysts or initiators, and no small molecule by-products are generated during the reaction process. In addition, the low polarity carbon-hydrogen chemical structure of benzocyclobutene itself makes it a low dielectric constant material with broad application prospects and excellent comprehensive performance. According to the Clausius-Mossotti equation, there are two main methods to reduce the dielectric constant of a material: one is to reduce the molecular polarizability, and the other is to reduce the molar polarizability per unit volume. Reducing the molecular polarizability is usually achieved by introducing specific atoms (such as C, F, Si, etc.) or chemical bonds (such as C-H, C-C, C-F, C-Si, etc.) with low polarizability. Among them, the carbon-hydrogen bond is the covalent bond with the lowest polarizability except the carbon-fluorine bond. Reducing the molar polarizability per unit volume is usually achieved by introducing bulky side groups (such as methyl, phenyl, adamantane, etc.). Norbornene (NB) is a cycloalkene, and its chemical structure contains a methylene bridge and a cyclohexene. The bridge ring structure has high tension, and the presence of double bonds makes norbornene have high activity in chemical reactions. Professor Xia Yan of Stanford University recently developed a highly efficient catalytic aromatic-norbornene cyclization (CANAL) polymerization method. In this method, zero-valent palladium forms a complex with aryl bromide, which can activate the C-H bond on the double bond of norbornene, and then through reductive elimination, the aryl bromide and norbornene undergo cyclization to form a norbornene-benzocyclobutene unit. SUMMARY

[0004] The present application aims to provide a linear rigid ladder structure-containing benzocyclobutene compound and a preparation method thereof.

[0005] In a first aspect, the present application provides a linear rigid ladder structure-containing benzocyclobutene compound, whose structural formula is shown in Formula I:

[0006]

[0007] In Formula I, the substituent R is selected from the following groups: C1-C6 alkyl, halogen-substituted C1-C3 alkyl.

[0008] Specifically, the R substituent is selected from any one of methyl and trifluoromethyl.

[0009] More specifically, the linear rigid ladder structure-containing benzocyclobutene compound has a structural formula shown in Formula I-a, Formula I-b, Formula I-c or Formula I-d:

[0010]

[0011]

[0012] In a second aspect, the present application provides a preparation method of the linear rigid structure-containing benzocyclobutene compound.

[0013] The preparation method of the linear rigid structure-containing benzocyclobutene compound provided by the present application is as follows: taking 2-bromo-5-chlorobenzene derivative as raw material, sequentially performing norbornene-arene cyclization (CANAL) reaction and Suzuki reaction to obtain the linear rigid ladder structure-containing benzocyclobutene compound.

[0014] Specifically, the preparation method of the linear rigid structure-containing benzocyclobutene compound provided by the present application comprises the following steps:

[0015] (1) performing arene-norbornene cyclization reaction (CANAL reaction) on the 2-bromo-5-chlorobenzene derivative shown in Formula II and the compound (norbornadiene) shown in Formula III in an inert organic solvent under the action of a catalyst, a ligand and a base to obtain the compound shown in Formula IV;

[0016]

[0017] The substituent R in Formula II and Formula IV is the same as the substituent R in Formula I;

[0018] (2) performing one-step Suzuki coupling reaction on the compound shown in Formula IV and 4-boronic acid ester benzocyclobutene in an inert organic solvent under the action of a catalyst, a ligand and a base to obtain the linear rigid ladder structure-containing benzocyclobutene compound shown in Formula I,

[0019]

[0020] The base in the step (1) is at least one of cesium fluoride, cesium carbonate, potassium fluoride and potassium carbonate;

[0021] The catalyst is at least one of palladium acetate, tris(dibenzylideneacetone)palladium and palladium tetraphenylphosphine;

[0022] The ligand is at least one of triphenylphosphine, diphenylphosphine and tri-tert-butylphosphine;

[0023] The inert organic solvent is at least one of 1,4-dioxane, toluene, dimethyl sulfoxide and dimethyl ether;

[0024] The molar ratio of the compound of formula II to the compound of formula III is (2-3):1;

[0025] The temperature of the arene-norbornene catalytic cyclization reaction is 100-150℃, and the time is 10-24 hours;

[0026] The inert organic solvent in the step (2) is at least one of toluene, tetrahydrofuran and 1,4-dioxane;

[0027] The ligand is at least one of triphenylphosphine, tricyclohexylphosphine, boron tetrafluoride tri-tert-butylphosphine and boron tetrafluoride tri-tert-butylphosphine (P(t-Bu)3HBF4);

[0028] The base is at least one of cesium fluoride, cesium carbonate, potassium fluoride and potassium carbonate;

[0029] The catalyst is at least one of tris(dibenzylideneacetone)dipalladium and [1,1'-bis(di-tert-butylphosphino)ferrocene]dichloropalladium;

[0030] The molar ratio of the compound of formula IV to 4-boronic acid ester benzocyclobutene is 1:(2-3);

[0031] The temperature of the one-step Suzuki coupling reaction is 90-110℃, and the time is 12-24 hours.

[0032] Both the arene-norbornene catalytic cyclization reaction and the Suzuki reaction are carried out in an oxygen-free pressure-resistant bottle.

[0033] The solvent in the application is an ultradry solvent, and specifically can be ultradry toluene, ultradry dioxane and ultradry acetonitrile.

[0034] The application also provides a linear benzocyclobutene resin containing a rigid ladder structure.

[0035] The linear rigid ladder structure-containing benzocyclobutene resin is prepared from the linear rigid ladder structure-containing benzocyclobutene compound shown in the above formula I as a monomer.

[0036] Specifically, the linear rigid ladder structure-containing benzocyclobutene resin has a structural formula as shown in formula V a-c.

[0037]

[0038] The substituent R in formula V a-c is the same as the substituent R in formula I.

[0039] The linear rigid ladder structure-containing benzocyclobutene resin is prepared by pre-polymerization of the linear rigid ladder structure-containing benzocyclobutene compound shown in formula I in an organic solvent under protection of an inert gas, and then cross-linking and curing by heating, or directly cross-linking and curing by heating.

[0040] Further, the organic solvent is at least one selected from toluene, o-xylene, 1,3,5-trimethylbenzene, N,N-dimethylformamide and N,N-dimethylacetamide.

[0041] The inert atmosphere for protection is at least one selected from nitrogen and argon.

[0042] The pre-polymerization temperature is 150-180°C, and the time is 12-36h, and specifically, heating and stirring at 160°C for 24h.

[0043] The heating cross-linking and curing temperature process is 150°C for 1h, 200°C for 1h, 235°C for 1h, 260°C for 3h and 300°C for 1h.

[0044] The linear rigid ladder structure-containing benzocyclobutene resin prepared from the linear rigid ladder structure-containing benzocyclobutene compound shown in formula I is also within the protection scope of the present application, which is applied to fields such as ultra-large scale integrated circuit multi-chip modules, polymer thin film waveguide devices, wafer level chip scale packaging, micro electro mechanical systems, liquid crystal display packaging and signal insulation component packaging.

[0045] The present application also provides an article.

[0046] The article contains the above compound, or the article is prepared from the above compound.

[0047] Preferably, the article is a sheet or film polymerized from the compound, or the article contains a sheet or film polymerized from the compound.

[0048] The article is prepared by the following method: forming the compound represented by formula I into a sheet or film by a method selected from the group consisting of heated molding, solution spin coating, or solution drop coating;

[0049] Preferably, the solution spin coating or solution drop coating comprises the steps of: dissolving the compound represented by formula I in an organic solvent to form a solution.

[0050] The present invention also provides a photoresist, which is prepared from components including a prepolymer of the compound represented by formula I, a photosensitizer and an organic solvent.

[0051] Based on the excellent properties of benzocyclobutene monomers and the norbornene cyclization method, this paper designed and synthesized a series of linear benzocyclobutene monomers with a rigid ladder structure and then cured them. The resulting resins have a backbone composed of repeating norbornene-benzocyclobutene units. By introducing side chains with different functional groups, the resin's various properties can be adjusted to better meet the higher requirements for dielectric layer materials in future high-frequency communication technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is the H NMR spectrum of the NBD-CH3 monomer prepared in Example 1 of the present invention.

[0053] Figure 2 This is the carbon spectrum of the NBD-CH3 monomer prepared in Example 1 of the present invention.

[0054] Figure 3 This is the H NMR spectrum of the NBD-CH3-BCB monomer prepared in Example 1 of the present invention.

[0055] Figure 4 The mass spectrum of the NBD-CH3-BCB monomer prepared in Example 1 of the present invention.

[0056] Figure 5 This is the H NMR spectrum of one of the isomers of the NBD-CF3 monomer prepared in Example 2 of the present invention.

[0057] Figure 6 This is the NMR carbon spectrum of one of the isomers of the NBD-CF3 monomer prepared in Example 2 of the present invention.

[0058] Figure 7 This is the H NMR spectrum of the NBD-CF3-BCB monomer prepared in Example 2 of the present invention.

[0059] Figure 8 The mass spectrum of the NBD-CF3-BCB monomer prepared in Example 2 of the present invention.

[0060] Figure 9 These are the TGA curves of the two polymers prepared in Examples 1 and 2 of the present invention under a nitrogen atmosphere.

[0061] Figure 10 CTE curves of the two polymers prepared in Examples 1 and 2 of the present application. DETAILED DESCRIPTION

[0062] The present application will be further described in conjunction with the specific embodiments thereof, given by way of illustration only and not by way of limitation. The following examples provided serve as a guide for further improvement by those skilled in the art, and do not in any way constitute a limitation on the present application.

[0063] The experimental methods in the following examples are all conventional methods, and are carried out according to the techniques or conditions described in the literature in the art or according to the product instructions, unless otherwise specified. The materials, reagents, etc. used in the following examples can be obtained commercially, unless otherwise specified.

[0064] Example 1

[0065] In a glove box, 0.231 g of palladium acetate, 0.5403 g of triphenylphosphine, 16.5231 g of cesium carbonate and 50 ml of 1,4 dioxane were added to a flame-dried 150 ml glass pressure bottle, and the mixture was stirred at room temperature for 30 minutes, then 10.4855 g of 2-bromo-5-chloromethyl toluene and 2.353 g of norbornadiene (NBD) were added. Then the pressure bottle was sealed with a Teflon valve, and the pressure bottle was taken out of the glove box and heated and stirred at 150°C for 24 hours. After cooling to room temperature, the mixture was filtered through a layer of diatomite to remove insoluble matter. The filtrate was concentrated by rotary evaporation, and the crude product was purified by elution with pure petroleum ether in a dry way to obtain NBD-CH3. 1 HNMR (300 MHz, Chloroform-d) δ = 7.00 (s, 2H), 6.83 (s, 2H), 3.22 (s, 4H), 2.38 (s, 2H), 2.17 (s, 6H), 0.77 (s, 2H).

[0066] Figure 1 NMR of the prepared NBD-CH3 monomer

[0067] Figure 2 NMR of the prepared NBD-CH3 monomer

[0068] In a nitrogen glove box, 1.7072 g of NBD-CH3, 2.315 g of 4BpinBCB, 0.28804 g of Pd2(dba)3, 0.2098 g of P(t-Bu)3HBF4 and 4.634 g of CsF were added to a 150 ml glass pressure bottle, then 75 ml of tetrahydrofuran solution was added to the pressure bottle, and the pressure bottle was sealed with a Teflon valve. The pressure bottle was taken out of the glove box and placed in a 110 °C oil bath for heating and stirring for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, and the mixture was filtered through diatomite to remove insoluble substances. The residue was washed with dichloromethane several times. After the filtrate was concentrated, silica gel powder was added, and the product was purified by dry loading and elution with pure petroleum ether to obtain NBD-CH3-BCB as a white solid (the product is a mixture of both formula I-a and I-b). (1.8 g 75.5%). 1 H NMR (300 MHz, Chloroform-d) δ = 7.35 (d, J = 7.7, 2H), 7.21 (s, 2H), 7.16 (s, 2H), 7.08 (d, J = 7.7, 2H), 7.00 (s, 2H), 4.12 (q, J = 7.0, 2H), 3.25 (d, J = 29.7, 12H), 2.45 (s, 2H), 2.25 (s, 7H), 2.05 (s, 2H).

[0069] Figure 3 NMR of the prepared NBD-CH3-BCB monomer.

[0070] Figure 4 Mass spectrum of the prepared NBD-CH3-BCB monomer.

[0071] Example 2

[0072] In a glove box, 0.2285 g of palladium acetate, 0.5833 g of triphenylphosphine, 16.3896 g of cesium carbonate and 50 ml of 1,4-dioxane were added to a flame-dried 150 ml glass pressure bottle, and the mixture was stirred at room temperature for 30 minutes, then 12.7247 g of 1-bromo-4-chloro-2-(trifluoromethyl)benzene and 2.363 g of NBD were added. Then the pressure bottle was sealed with a Teflon valve, and the pressure bottle was taken out of the glove box and heated and stirred at 150 °C for 24 hours. After cooling to room temperature, the mixture was filtered through a layer of diatomite to remove insoluble substances. After the filtrate was concentrated by rotary evaporation, the crude product was purified by dry loading and elution with pure petroleum ether to obtain NBD-CF3 as a white solid with a yield of 26%. 1H NMR (400MHz, Chloroform-d) δ = 7.41 (s, 2H), 7.19 (s, 2H), 3.42 (d, J = 2.9, 4H), 2.54 (s, 2H), 0.79 (s, 2H).

[0073] Figure 5 This is the H NMR spectrum of one of the isomers of the prepared NBD-CF3 monomer.

[0074] Figure 6 This is the NMR carbon spectrum of one of the isomers of the prepared NBD-CF3 monomer.

[0075] In a nitrogen glove box, 2.69 g of NBD-CF₃, 2.76 g of 4BpinBCB, 0.33 g of Pd₂(dba)₃, 0.30 g of P(t-Bu)₃HBF₄, and 5.56 g of CsF were added to a 150 ml glass pressure bottle. 75 ml of tetrahydrofuran solution was then added to the bottle, which was sealed with a Teflon valve. The pressure bottle was removed from the glove box and heated in a 110°C oil bath with stirring for 24 hours. After the reaction was complete and the system cooled to room temperature, the mixture was passed through celite to remove insoluble matter. The residue was washed several times with dichloromethane. The filtrate was concentrated and silica gel powder was added. The product was then purified by dry loading with pure petroleum ether to obtain NBD-CF₃-BCB as a white solid in 80% yield. 1 H NMR (300MHz, Chloroform-d) δ = 7.56 (s, 2H), 7.35 (d, J = 8.3, 4H), 7.22 (s, 2H), 7.12 (d, J = 7.6, 2 H),3.55-3.50(m,2H),3.46-3.41(m,2H),3.22(s,8H),2.64(s,1H),2.52(s,1H),2.04(s,3H).

[0076] Figure 7 This is the H NMR spectrum of the prepared NBD-CF3-BCB monomer.

[0077] Figure 8 This is the mass spectrum of the prepared NBD-CF3-BCB monomer.

[0078] Example 3: Thin film preparation experiment

[0079] Preparation of prepolymer:

[0080] In three Schlenk tubes, 0.8 g of NBD-CH3-BCB, NBD-CF3-BCB and 3.2 g of mesitylene were added respectively, keeping the solid content at 20%. The oxygen in the mixture was removed by 3 "freeze-pump-thaw" cycles, and the Schlenk tubes were sealed and heated at 160 °C for 24 hours under stirring to obtain the prepolymer.

[0081] Preparation of thin films:

[0082] The prepolymer was removed from the excess mesitylene by rotary evaporation, keeping the concentration of the prepolymer at 400 mg / ml. 1 ml of prepolymer with a concentration of 400 mg / ml was added to a stainless steel tank with a diameter of 3.5 cm, and 0.8 ml was added to a glass bottle with a diameter of 1 cm. The stainless steel tank and the glass bottle were placed in a high-temperature nitrogen curing oven, and the polymer was completely cured by gradient heating (150 °C for 1 hour, 200 °C for 1 hour, 235 °C for 1 hour, 260 °C for 3 hours, 300 °C for 1 hour) under a nitrogen atmosphere to obtain the final polymer sheet.

[0083] Dielectric property test: The dielectric constant and dielectric loss of the polymer sheet were characterized using a 10 GHz split post dielectric resonator (SPDR) equipped with a microwave Q-Meter meter under QWED, Poland.

[0084] Table 1 Dielectric constant and dielectric loss of three polymer materials at 10 GHz

[0085]

[0086] Thermogravimetric analysis (TGA): The two polymers were measured in a nitrogen atmosphere using a simultaneous thermal analyzer TA Q600, with a heating rate of 10 °C / min and a temperature range of 40-800 °C. The results are shown in Figure 9 .

[0087] Thermodynamic analysis (TMA): The two polymers were measured on a TA Q400 instrument (sample: cylinder with a diameter of 1 cm and a height of 4 mm). The measurement was carried out in expansion mode, with a heating rate of 5 °C / min and a temperature range of 50-350 °C, and the coefficient of thermal expansion (CTE) was determined. The results are shown in Figure 10 .

[0088] The application has been described in detail. For those skilled in the art, the application can be implemented in a wider range under equivalent parameters, concentrations and conditions without departing from the spirit and scope of the application and without unnecessary experiments. Although the application gives special examples, it should be understood that the application can be further improved. In summary, according to the principle of the application, the application intends to include any change, use or improvement of the application, including changes made by conventional techniques known in the art, which deviates from the range disclosed in the application.

Claims

1. A linear benzocyclobutene compound containing a rigid ladder structure, the structural formula of which is shown in Formula I: In formula I, the substituent R is selected from the following groups: C1-C6 alkyl, halogen-substituted C1-C3 alkyl.

2. The compound according to claim 1, characterized in that In formula I, the substituent R is selected from any one of methyl and trifluoromethyl.

3. A method for preparing the compound according to any one of claims 1 or 2, comprising the following steps: (1) in an inert organic solvent, in the presence of a catalyst, a ligand, and a base, subjecting a 2-bromo-5-chlorobenzene derivative of formula II and a compound of formula III to an aromatic hydrocarbon-norbornene cyclization reaction (CANAL reaction) to obtain a compound of formula IV; The substituents R in formula II and formula IV are the same as the substituents R in formula I; (2) In an inert organic solvent, in the presence of a catalyst, a ligand, and a base, the compound represented by Formula IV undergoes a one-step Suzuki coupling reaction with 4-boronic acid ester benzocyclobutene to obtain a linear benzocyclobutene compound containing a rigid ladder structure represented by Formula I. 。 4. The method according to claim 3, characterized in that In step (1), the base is at least one of cesium fluoride, cesium carbonate, potassium fluoride and potassium carbonate; The catalyst is at least one of palladium acetate, tris(dibenzylideneacetone)palladium, and tetrakistriphenylphosphine palladium; The ligand is at least one of triphenylphosphine, diphenylphosphine and tri-tert-butylphosphine; The inert organic solvent is at least one of 1,4-dioxane, toluene, dimethyl sulfoxide, and dimethyl ether; The molar ratio of the compound represented by formula II to the compound represented by formula III is (2-3):1; The temperature of the aromatic hydrocarbon-norbornene cyclization reaction is 100-150° C. and the time is 10-24 hours; In step (2), the ligand is at least one of triphenylphosphine, tricyclohexylphosphine, and tri-tert-butylphosphine tetrafluoride (P(t-Bu)3HBF4); The base is at least one of cesium fluoride, cesium carbonate, potassium fluoride and potassium carbonate; The catalyst is at least one of tris(dibenzylideneacetone)dipalladium and [1,1'-bis(di-tert-butylphosphino)ferrocene]palladium dichloride; The molar ratio of the compound represented by formula IV to 4-boronic acid ester benzocyclobutene is 1:(2-3); The temperature of the one-step Suzuki coupling reaction is 90-110° C., and the reaction time is 12-24 hours.

5. A linear benzocyclobutene resin containing a rigid ladder structure, characterized in that: The resin is prepared by prepolymerizing the linear benzocyclobutene compound containing a rigid ladder structure shown in formula I of claim 1 or 2 in an organic solvent under the protection of an inert gas to obtain a prepolymer, and then heating and crosslinking and curing it, or directly heating and curing and crosslinking it.

6. The linear benzocyclobutene resin containing a rigid ladder structure according to claim 5 is used as a packaging material or interlayer insulating material in ultra-large-scale integrated circuit multi-chip modules, polymer film waveguides, wafer-level chip scale packaging, micro-electromechanical systems, liquid crystal display packaging, and signal insulation component packaging.

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