A benzocyclobutene monomer and resin that can be cured at low temperatures and exhibits aggregation-induced light emission, a preparation method, and a photoresist.

Abstract

This invention discloses a benzo[a]cyclobutene monomer and resin that can be cured at low temperatures and exhibits aggregation-induced emission, a preparation method, and a photoresist. The structural formula of the tetraphenylethylene-functionalized benzo[a]cyclobutene monomer of this invention is shown in Formula I, where R1, R2, R3, and R4 are each independently selected from hydrogen, C1-C8 alkyl, fluorine, phenyl, vinyl, trifluoropropyl, or perfluorooctyl. This invention obtains a tetraphenylethylene-functionalized benzo[a]cyclobutene monomer by introducing a tetraphenylethylene group onto a BCB four-membered ring. The tetraphenylethylene-functionalized benzo[a]cyclobutene monomer is then cured by heating to form a resin. This resin exhibits significant low-temperature curing characteristics, low dielectric constant and dielectric loss, low moisture absorption, and good mechanical properties. Furthermore, this tetraphenylethylene-functionalized benzo[a]cyclobutene prepolymer can be cured under ultraviolet light to form a target pattern with fluorescent effects.

Description

Technical Field

[0001] This invention belongs to the field of high-performance electronic packaging resins, specifically relating to a benzocyclobutene monomer and resin that can be cured at low temperatures and has aggregation-induced light emission effect, a preparation method, and a photoresist. Background Technology

[0002] With the rapid development of fifth-generation mobile communication technology (5G), significant progress has been made in the fields of the Internet of Things (IoT) and augmented reality. Advances in 5G technology have spurred the development of a series of flexible wearable electronic products such as smartphones, smart bracelets, and smart glasses, which are ubiquitous in daily life. All electronic products rely on a tiny chip. As microelectronics become increasingly miniaturized and lightweight, chip integration is constantly increasing, placing higher demands on packaging technology and materials. Innovative research and development of higher-performance packaging materials has become a key focus. Commonly used packaging materials such as epoxy resin, polyimide, polybenzoxazole, and benzocyclobutene (BCB) have become superior choices for multilayer wiring processes in integrated circuit manufacturing. For example, commercially available DVSBCB resin is renowned for its excellent dielectric properties, high thermal stability, low water absorption, and dimensional stability, making it an ideal interlayer dielectric material in multi-chip components. However, traditional BCB thermosetting materials still have considerable room for development.

[0003] Organic thin-film transistors (OTCs), crucial imaging electronic components in flexible liquid crystal displays, often employ flexible substrate materials such as polyethylene terephthalate (PET), which typically cannot withstand the excessively high curing temperatures of the polymer dielectric layer. Research reports that introducing substituents onto the four-membered ring of BCB can significantly lower the activation energy barrier of the ring-opening reaction, thereby reducing the ring-opening temperature (in this invention, the ring-opening temperature refers to the peak ring-opening temperature of the differential scanning calorimetry (DSC) curve). Previous studies on low-temperature crosslinked benzocyclobutene mainly focus on the complex synthesis of BCB monomers, and the crosslinked polymers are often unstable or require additional crosslinking agents for polymerization.

[0004] Furthermore, the need for improved positioning accuracy is increasingly prominent in the wafer bonding process of three-dimensional stacked chip packaging. Currently, positioning tools used for multilayer wafer bonding mainly rely on optical microscopes. To address this challenge, we explore replacing existing interlayer positioning materials with luminescent materials, aiming to achieve higher positioning accuracy through fluorescence microscopy. In recent decades, luminescent materials have received widespread attention in fields such as fluorescence sensing, information storage, bioimaging, and crack detection. Tetraphenylene oxide (TPE), due to its ease of synthesis, ease of modification, and stable luminescent properties, has become one of the most widely studied aggregation-induced emission (AIE) molecules in the field of luminescent materials.

[0005] In summary, given the shortcomings of traditional BCB resins and the current demands of encapsulation technology, the urgent technical problem to be solved is how to introduce suitable groups onto the four-membered ring of BCB resins to enable the cured resin to possess both low-temperature curing and aggregation-induced light emission properties, thereby more comprehensively meeting the market's demand for BCB resins with different property requirements. Summary of the Invention

[0006] The purpose of this invention is to provide a benzo[a]cyclobutene monomer and resin that can be cured at low temperatures and exhibits aggregation-induced emission (AIE) effects, along with a preparation method and a photoresist. This invention introduces tetraphenylethylene groups onto the four-membered ring of BCB, resulting in a tetraphenylethylene-functionalized benzo[a]cyclobutene resin with significant low-temperature curing characteristics. It can be cured by heating the tetraphenylethylene-functionalized benzo[a]cyclobutene monomer. The material exhibits low dielectric constant and dielectric loss, low moisture absorption, and good mechanical properties. Furthermore, this tetraphenylethylene-functionalized benzo[a]cyclobutene polymer can also be cured under ultraviolet light to form fluorescent target patterns. The fully cured BCB resin prepared by this invention is expected to become a novel encapsulation material with higher positioning accuracy applicable to high-temperature sensitive fields.

[0007] In a first aspect, the present invention provides a tetraphenylethylene-functionalized benzocyclobutene monomer, the structural formula of which is shown in Formula I:

[0008]

[0009] In Formula I, R1, R2, R3, and R4 are each independently selected from hydrogen, C1-C8 alkyl, fluorine, phenyl, vinyl, trifluoropropyl, or perfluorooctyl.

[0010] In the above-mentioned tetraphenylethylene functionalized benzocyclobutene monomer, R1, R2, R3, and R4 may be the same or different. For example, R1, R2, R3, and R4 may be the same and selected from hydrogen, C1-C8 alkyl, fluorine, phenyl, vinyl, trifluoropropyl, or perfluorooctyl; or R1 and R3 may be the same, and R2 and R4 may be the same, each independently selected from hydrogen, C1-C8 alkyl, fluorine, phenyl, vinyl, trifluoropropyl, or perfluorooctyl.

[0011] The term C1-C8 alkyl refers to straight-chain or branched alkyl groups with 1 or more but less than 8 carbon atoms. Examples include "C1-4 alkyl" such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and tert-butyl, and further include n-pentyl, 3-methylbutyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, n-hexyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 3-ethylbutyl, 2-ethylbutyl, and n-octyl. C1-20 alkyl also includes C1-6 alkyl groups with 1 or more but less than 6 carbon atoms.

[0012] As an example, the structural formula of the tetraphenylethylene-functionalized benzocyclobutene monomer is shown as formula I-a, I-b, or I-c:

[0013]

[0014] Secondly, the present invention provides a method for preparing the tetraphenylethylene-functionalized benzocyclobutene monomer, comprising the following steps:

[0015] (1) In the presence of titanium tetrachloride, the compound shown in Formula II and the compound shown in Formula III were subjected to a McMurray coupling reaction in a dry solvent under the action of a reducing agent to obtain the compound shown in Formula IV.

[0016]

[0017] In Equation II, R1 and R2 are defined in the same way as in Equation I;

[0018] In Equation III, R3 and R4 are defined in the same way as in Equation I;

[0019] In Equation IV, the definitions of R1, R2, R3, and R4 are the same as in Equation I;

[0020] (2) Under the action of an inorganic base, the compound shown in Formula IV is subjected to Williamson etherification reaction with 1-bromo-benzocyclobutene or 1-chlorobenzocyclobutene in an inert solvent to obtain the tetraphenylethylene-functionalized benzocyclobutene monomer.

[0021] In the above preparation method, the molar ratio of the compound shown in Formula II to the compound shown in Formula III can be 1:(1~1.5); it can be understood that when R1 and R3 are the same, and R2 and R4 are the same, the compound shown in Formula II is the same as the compound shown in Formula III.

[0022] The reducing agent is zinc powder;

[0023] The molar ratio of titanium tetrachloride to the reducing agent can be 1:2;

[0024] The drying solvent may be ultra-dry tetrahydrofuran;

[0025] The McMurray coupling reaction can be carried out at a temperature of 70–80°C, such as reflux temperature, and for a time of 10–12 hours, such as 11 hours.

[0026] The McMurray coupling reaction takes place in an anaerobic environment;

[0027] In step (1), the product undergoes the following post-processing:

[0028] (i) Quench with a 10% potassium carbonate solution;

[0029] (ii) Filter the reaction solution and extract it sequentially with saturated sodium bicarbonate, saturated saline and dichloromethane. Evaporate the solvent and purify the solution by column chromatography to obtain a pale green compound.

[0030] The inorganic base may be potassium carbonate, sodium carbonate, cesium carbonate, potassium hydroxide, or sodium hydroxide.

[0031] The molar ratio of the compound shown in Formula IV to the 1-bromo-benzocyclobutene or 1-chloro-benzocyclobutene can be 1:(2.2-3), specifically 1:2.5;

[0032] The inert solvent may be ultra-dry dimethyl sulfoxide, ultra-dry N,N-dimethylformamide, or ultra-dry N,N-dimethylacetamide;

[0033] The temperature of the Williamson etherification reaction can be 50-55°C, such as 50°C, and the time can be 10-12 hours, such as 11 hours.

[0034] The Williamson etherification reaction was carried out in an anaerobic environment;

[0035] In step (2), the product undergoes the following post-processing:

[0036] (i) Pass the mixture (yellow emulsion) after the reaction through a short silica gel pad and rinse the silica gel pad repeatedly with ethyl acetate, and collect the filtrate.

[0037] (ii) Extract the filtrate with saturated saline solution, remove water with anhydrous magnesium sulfate, and then evaporate the solvent to obtain a yellow solid.

[0038] (iii) The obtained yellow solid was purified by column chromatography to obtain a yellow compound with high purity.

[0039] Thirdly, the present invention provides a tetraphenylethylene-functionalized benzocyclobutene resin, the structural formula of which is shown in Formula V:

[0040]

[0041] In formula V, R1, R2, R3, and R4 are each independently selected from hydrogen, C1-C8 alkyl, fluorine, phenyl, vinyl, trifluoropropyl, or perfluorooctyl; n is any integer from 3 to 100.

[0042] As an example, the structural formula of the resin of formula V is shown in formula Va:

[0043]

[0044] Fourthly, the present invention provides a tetraphenylethylene-functionalized benzocyclobutene resin, which is obtained by heating the tetraphenylethylene-functionalized benzocyclobutene monomer in an inert solvent and then crosslinking and curing it.

[0045] In the above-mentioned tetraphenylethylene-functionalized benzocyclobutene cured resin, the inert solvent is selected from toluene, o-xylene, 1,3,5-trimethylbenzene, N,N-dimethylformamide or N,N-dimethylacetamide;

[0046] The cross-linking and curing process is carried out in a vacuum environment;

[0047] The heating is a gradient temperature increase, with the following conditions: 150℃ / 1h, 160℃ / 1h, 170℃ / 3h.

[0048] Fifthly, the present invention provides a tetraphenylethylene-functionalized benzocyclobutene prepolymer, which is obtained by heating the tetraphenylethylene-functionalized benzocyclobutene monomer in an inert solvent and then prepolymerizing it.

[0049] In the above-mentioned tetraphenylethylene functionalized benzocyclobutene prepolymer, the inert solvent is selected from toluene, o-xylene, 1,3,5-trimethylbenzene, N,N-dimethylformamide or N,N-dimethylacetamide;

[0050] The heating temperature is 120-150°C, and the time is 20-36 hours, such as prepolymerization at 130°C for 24 hours.

[0051] The post-processing steps in the prepolymerization step are as follows: after the solvent in the reaction mixture is evaporated, it is dissolved in dichloromethane, anhydrous ethanol is added to precipitate, the mixture is allowed to stand, and centrifuged to obtain a pale yellow solid.

[0052] In a sixth aspect, the present invention provides the use of the tetraphenylethylene-functionalized benzocyclobutene resin or the tetraphenylethylene-functionalized benzocyclobutene prepolymer as an encapsulation material or an interlayer positioning material.

[0053] In a seventh aspect, the present invention provides a photoresist made of a composition comprising the aforementioned tetraphenylethylene functionalized benzocyclobutene prepolymer, a photosensitizer, and an organic solvent.

[0054] The weight proportions of each component in the above photoresist are as follows:

[0055] The tetraphenylethylene-functionalized benzocyclobutene prepolymer is 1-1.5 parts;

[0056] The photosensitizer is 0.03 to 0.3 parts;

[0057] The organic solvent is 5 to 50 parts.

[0058] In an optional embodiment of the present invention, the photoresist is made of a component comprising the following parts by weight:

[0059] One part of the tetraphenylethylene-functionalized benzocyclobutene polymer;

[0060] Photosensitizer 0.03–0.3 parts;

[0061] 5 to 50 parts of organic solvent.

[0062] As an example, the photoresist is made of components comprising the following parts by weight:

[0063] One part of the tetraphenylethylene-functionalized benzocyclobutene polymer;

[0064] 0.1 parts photosensitizer;

[0065] 10 parts organic solvent.

[0066] In the above-mentioned photoresist, the photosensitizer is an azide-based organic compound with the structural formula shown in Formula VI:

[0067]

[0068] In formula VI, R is any group;

[0069] The organic solvent is toluene, o-xylene, mesitylene, dichloromethane, chloroform, or tetrahydrofuran.

[0070] As an example, the photosensitizer is a compound of formula VI-a, but is not limited to the structure shown in formula VI-a.

[0071]

[0072] The chemical name of the compound shown in Formula VI-a is 2,6-bis(4-azidobenzylidene)-4-ethylcyclohexanone (BAC-E).

[0073] The present invention has the following beneficial effects:

[0074] This invention provides a benzocyclobutene monomer and resin that can be cured at low temperatures and exhibits aggregation-induced emission through a Williamson etherification reaction. The resin exhibits significant low-temperature curing characteristics and superior dielectric properties at both low and high frequencies. It also possesses good hydrophobic properties, with a large hydrophobic angle and low water absorption. Furthermore, the resin displays unique fluorescent properties and high positioning accuracy, making it a promising candidate for use as a wafer bonding positioning material in chip packaging. The photoresist formulated with the polymer and photosensitizer of this invention produces a uniform film thickness and clear pattern edges after curing. The bulk or modified resin can be applied in fields such as large-scale integrated circuit multi-chip modules, polymer thin-film waveguides, wafer-level chip-scale packaging, micro-motor systems, liquid crystal display packaging, and flexible wearable electronic product packaging. Attached Figure Description

[0075] Figure 1 The above is the 1H NMR spectrum of the monomer of formula I-a in Example 2 of this invention.

[0076] Figure 2 The differential scanning calorimetry (DSC) curve of monomer I-a in Example 3 of this invention is shown.

[0077] Figure 3 The images show the photocrosslinking mechanism (a), photolithographic pattern optical microscope images (b-c), and fluorescence microscope images (d-e) of the photoresist compounded with formula V-a prepolymer and photosensitizer in Example 6 of this invention.

[0078] Figure 4 The image shows a scanning electron microscope image of the photolithographic pattern of the photoresist compounded with formula V-a prepolymer and photosensitizer in Example 6 of this invention.

[0079] Figure 5 The results of the photolithographic pattern profilometer test are for the photoresist compounded with formula V-a prepolymer and photosensitizer in Example 6 of this invention. Detailed Implementation

[0080] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0081] Unless otherwise specified, the methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials, reagents, etc., used in the following examples are commercially available. Percentages and parts are by weight unless otherwise stated.

[0082] Example 1: Synthesis of compound IV-a (according to the method described in Angewandte Chemie International Edition, 2015, 54(50), 15160-15164)

[0083]

[0084] 5 g (25 mmol) of compound II-a, 7.25 g (110 mmol) of zinc powder, and 250 mL of ultra-dry tetrahydrofuran were added to a 500 mL flame-dried three-necked flask. The mixture was bubbled under ice bath conditions for 30 min to remove oxygen. After cooling to -78 °C, titanium tetrachloride (6.25 mL, 55 mmol) was added dropwise. The mixture was slowly heated to room temperature and stirred for 0.5 h, then refluxed overnight (11 h) at reflux temperature. The reaction mixture was quenched with a 10% potassium carbonate aqueous solution after completion. The reaction solution was filtered and extracted successively with saturated sodium bicarbonate solution, saturated brine, and dichloromethane. The solvent was evaporated, and the solution was purified by column chromatography to obtain a light green compound IV-a in 81% yield. Eluent: petroleum ether / ethyl acetate (v / v 1:1).

[0085] 1 H NMR (300MHz, CDCl3) δ = 7.06 (m, 11H), 6.88 (t, J = 8.8Hz, 3H), 6.56 (t, J = 9.1Hz, 4H)

[0086] Example 2: Synthesis of Compound I-a

[0087]

[0088] 1 g (2.746 mmol) of compound IV-a and 4.47 g (13.73 mmol) of Cs₂CO₃ were placed in a 50 mL three-necked flask, and 20 mL of ultra-dry DMSO was added. The mixture was bubbled to remove oxygen for 30 min, and then 1.25 g (6.87 mmol) of 1-bromo-benzocyclobutene was added. The reaction was carried out overnight (11 h) at 50 °C. After the reaction was completed, the reaction solution was filtered, extracted with saturated brine and ethyl acetate, and the excess solvent was removed by rotary evaporation. The solution was then purified by column chromatography to give 1.159 g of a yellow solid, with a yield of 74.3%. Eluent: petroleum ether / ethyl acetate (v / v 300:1).

[0089] The proton NMR spectrum is as follows Figure 1 As shown.

[0090] 1 H NMR(300MHz, CDCl3)δ=7.32(t,J=6.0Hz,2H),7.24–7.20(m,3H),7.19-7.14(m,4H),7.13-7.04(m,9H),6.98(t ,J=9.0Hz,4H),6.76(dd,J=12.0,9.0Hz,4H),5.61(t,J=6.0Hz,2H),3.66(m,2H),3.27(dd,J=15.0,3.0Hz,2H).

[0091] 13C NMR(75MHz, CDCl3)δ=156.52,156.48,144.78,144.22,144.11,142.63,139.85,136.88,136.79,132.66,131.47, 129.87,127.73,127.62,127.38,127.34,126.27,126.24,123.45,123.10,114.31,114.25,74.21,39.49,39.45.

[0092] Example 3: Synthesis of Compound IV-b

[0093]

[0094] 5.3 g (25 mmol) of compound II-b, 7.25 g (110 mmol) of zinc powder, and 250 mL of ultra-dry tetrahydrofuran were added to a 500 mL flame-dried three-necked flask, and the mixture was bubbled under ice bath conditions for 30 min to remove oxygen. The mixture was cooled to -78 °C, and titanium tetrachloride (6.25 mL, 55 mmol) was added dropwise. The mixture was slowly heated to room temperature and stirred for 0.5 h, then refluxed overnight (11 h) at reflux temperature. After the reaction was complete, the solution was quenched with a 10% potassium carbonate aqueous solution. The reaction solution was filtered, and extracted successively with saturated sodium bicarbonate solution, saturated brine, and dichloromethane. The solvent was evaporated, and the solution was purified by column chromatography to obtain 4.06 g of compound IV-b in 83% yield. Eluent: petroleum ether / ethyl acetate (v / v1:1).

[0095] 1 H NMR (300MHz, CDCl3) δ = 7.12 (m, 10H), 6.74 (t, J = 8.8Hz, 2H), 6.62 (t, J = 9.1Hz, 4H), 2.40 (s, 6H).

[0096] Example 4: Synthesis of Compound I-b

[0097]

[0098] 1.08 g (2.75 mmol) of compound IV-a and 4.47 g (13.73 mmol) of Cs₂CO₃ were placed in a 50 mL three-necked flask, and 20 mL of ultra-dry DMSO was added. The mixture was bubbled to remove oxygen for 30 min, and then 1.25 g (6.87 mmol) of 1-bromo-benzocyclobutene was added. The reaction was carried out overnight (11 h) at 50 °C. After the reaction was completed, the reaction solution was filtered, extracted with saturated brine and ethyl acetate, and the excess solvent was removed by rotary evaporation. The solution was then purified by column chromatography to give 1.15 g of solid, with a yield of 70%. Eluent: petroleum ether / ethyl acetate (v / v 300:1).

[0099] 1 H NMR(300MHz, CDCl3)δ=7.32(t,J=6.0Hz,2H),7.25–7.20(m,3H),7.18-7.14(m,4H),7.14-7.04(m,7H),6.97(t,J=9.0 Hz,4H),6.76(dd,J=12.0,9.0Hz,4H),5.60(t,J=6.0Hz,2H),3.66(m,2H),3.28(dd,J=15.0,3.0Hz,2H),2.40(s,6H).

[0100] Example 5: Synthesis of Compound IV-c

[0101]

[0102] 5.4 g (25 mmol) of compound II-c, 7.25 g (110 mmol) of zinc powder, and 250 mL of ultra-dry tetrahydrofuran were added to a 500 mL flame-dried three-necked flask. The mixture was bubbled under ice bath conditions for 30 min to remove oxygen. After cooling to -78 °C, titanium tetrachloride (6.25 mL, 55 mmol) was added dropwise. The mixture was slowly heated to room temperature and stirred for 0.5 h, then refluxed overnight (11 h) at reflux temperature. The reaction mixture was quenched with a 10% potassium carbonate aqueous solution after completion. The reaction solution was filtered and extracted successively with saturated sodium bicarbonate solution, saturated brine, and dichloromethane. The solvent was evaporated, and the solution was purified by column chromatography to obtain 3.85 g of compound IV-c in 77% yield. Eluent: petroleum ether / ethyl acetate (v / v 1:1).

[0103] 1 H NMR (300MHz, CDCl3) δ = 7.09 (m, 10H), 6.70 (t, J = 8.8Hz, 2H), 6.58 (t, J = 9.1Hz, 4H)

[0104] Example 6: Synthesis of Compound I-c

[0105]

[0106] 1.1 g (2.75 mmol) of compound IV-c and 4.47 g (13.73 mmol) of Cs₂CO₃ were placed in a 50 mL three-necked flask, and 20 mL of ultra-dry DMSO was added. The mixture was bubbled to remove oxygen for 30 min, and then 1.25 g (6.87 mmol) of 1-bromo-benzocyclobutene was added. The reaction was carried out overnight (11 h) at 50 °C. After the reaction was completed, the reaction solution was filtered, extracted with saturated brine and ethyl acetate, and excess solvent was removed by rotary evaporation. The solution was then purified by column chromatography to give 1.25 g of solid Ic, with a yield of 75%. Eluent: petroleum ether / ethyl acetate (v / v 300:1).

[0107] 1 H NMR(300MHz, CDCl3)δ=7.32(t,J=6.0Hz,2H),7.28–7.22(m,3H),7.17-7.14(m,4H),7.15-7.06(m,7H),6.98(t ,J=9.0Hz,4H),6.74(dd,J=12.0,9.0Hz,4H),5.48(t,J=6.0Hz,2H),3.64(m,2H),3.26(dd,J=15.0,3.0Hz,2H).

[0108] Example 7: Ring-opening temperature characterization of monomer of formula I-a

[0109] Weigh 3–5 mg of the monomer of formula I-a and place it in a solid alumina crucible, spreading it evenly. Determine the ring-opening temperature using differential scanning calorimetry. The test results are as follows: Figure 2 As shown. Test atmosphere: nitrogen; flow rate: 50 mL / min. (From...) Figure 2 It can be seen that the peak ring-opening temperature of the polymer monomer is 188℃, and the introduction of ether bonds on the four-membered ring of BCB can greatly reduce the ring-opening temperature.

[0110] Example 8: Curing and property characterization of resin of formula V-a

[0111] 500 mg of the I-a monomer was completely dissolved in 2 mL of 1,3,5-trimethylbenzene solution and placed in a mold. The solution was then cured in a vacuum environment by gradient heating (150℃ / 1h, 160℃ / 1h, 170℃ / 3h) to obtain a yellow sheet (diameter: 3.5 cm, thickness: 0.4 cm).

[0112] The dielectric constants of Formula V-a resin and DVSBCB resin were measured using the parallel-plate capacitor method at room temperature in the range of 10 Hz to 1 MHz, and the dielectric constants of Formula V-a resin and DVSBCB resin were measured using the resonant cavity method at 10 GHz. The dielectric constants ranged from 2.6 to 2.8. The dielectric loss factor was 1.3 × 10⁻⁶. -3 ~3.15×10 -3Dielectric property tests show that the dielectric constant of the cured V-a resin is lower than that of DVSBCB in the range of 10 Hz to 1 MHz, and still lower than 2.8 at 10 GHz.

[0113] The immersion water absorption rate and contact angle of the resin cured at room temperature for 72 hours were determined at room temperature. The weight changes of both resins were measured by immersing them in beakers filled with deionized water at room temperature; the weight changes for both Formula V-a resin and DVSBCB resin were as low as 0.23%. The static contact angles of formula V-a resin and DVSBCB resin were characterized at room temperature using a DSA 100 instrument. Both resins exhibited nearly identical large hydrophobic angles (109° for TPE-BCB resin and 108° for DVSBCB resin), indicating comparable hydrophobic properties.

[0114] The thermal stability of the V-a resin was determined by thermogravimetric analysis (TGA). The 5% thermogravimetric loss temperature in nitrogen was 248℃. The sample amount was 3-5 mg, and the nitrogen flow rate was 50 mL / min.

[0115] The mechanical properties of the V-a resin were determined by nanoindentation. The hardness was 0.33 GPa, the Young's modulus was 0.44 GPa, the maximum penetration depth was 2000 nm, and the sample size was 3.5 cm in diameter and 0.4 cm in thickness.

[0116] Example 9: Preparation of Prepolymer of Formula V-a

[0117] 500 mg of monomer of formula I-a and 4.5 g of 1,3,5-trimethylbenzene solvent were added sequentially to a 120 mL high-temperature pressure-resistant bottle, and the mixture was deoxygenated three times by freezing with liquid nitrogen. The reaction system was placed at 130 °C for prepolymerization for 24 h. After the solvent in the reaction mixture was evaporated, it was dissolved in 5 mL of dichloromethane, precipitated by adding 50 mL of anhydrous ethanol, allowed to stand, and centrifuged to obtain a pale yellow prepolymer of formula V-a (number average molecular weight: 13163, PDI: 1.56).

[0118] Example 10: Preparation of photoresist

[0119] (1) Preparation of photosensitizer VI-a compound

[0120] 10 g (30 mmol) of 2,6-bis-(4-aminobenzylmethyl)-4-ethyl-cyclohexanone was added to a beaker and placed in an ice-water bath. 150 mL of cooled 2.5 mol / L (375 mmol) aqueous sodium nitrite solution was added dropwise. Then, 167 mL of 1 mol / L (375 mmol) hydrochloric acid solution was slowly added dropwise with stirring. The pH was adjusted to 7-8 with sodium bicarbonate. 8.32 g (72 mmol) of azidotrimethylsilane was added. After stirring at 0 °C for 10 min, recrystallization yielded 10.1 g of a brick-red product, formula VI-a (2,6-bis-(4-azidobenzylmethyl)-4-ethyl-cyclohexanone). The yield was 94%.

[0121] 1 H NMR (300MHz, CDCl3) δ = 7.75 (s, 2H), 7.48 (d, J = 8.2Hz, 4H), 7.08 (d, J = 8.1Hz, 4 H),3.13-3.00(m,2H),2.57-2.44(m,2H),1.43(m,2H),0.90(t,J=7.4Hz,3H).

[0122] (2) Photolithography process and surface morphology of photolithographic pattern

[0123] 100 mg of prepolymer V-a and 10 mg of photosensitizer 2,6-bis-(4-azidobenzylmethyl)-4-ethyl-cyclohexanone were dissolved in 1 mL of toluene solution and stirred until homogeneous to prepare a photosensitive adhesive. The photosensitive adhesive was spin-coated onto a silicon wafer (1000 rpm, 10 s; 2000 rpm, 60 s), and then baked at 80°C for 2 min. The silicon wafer was then exposed to 365 nm ultraviolet light in a photolithography machine for 5 s, followed by development with a developer for 35 s. The resulting photolithographic pattern was observed, and its surface morphology was analyzed using optical microscopy, fluorescence microscopy, and scanning electron microscopy images, as shown below. Figure 3 and Figure 4 The photolithographic pattern clearly exhibits a significant fluorescent effect. Its surface profile test curve is shown below. Figure 5 As shown, a resolution of 10 μm can be achieved with a uniform film thickness of 230 nm.

[0124] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including modifications made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. A tetraphenylethylene-functionalized benzocyclobutene monomer, the structural formula of which is shown in Formula I: In Formula I, R1, R2, R3, and R4 are each independently selected from hydrogen, C1-C8 alkyl groups, and fluorine.

2. The tetraphenylsilylethylene-functionalized benzocyclobutene monomer according to claim 1, characterized in that: The structural formula of the tetraphenylethylene-functionalized benzocyclobutene monomer is shown in formula I-a, I-b, or I-c:

3. The method for preparing the tetraphenylethylene-functionalized benzocyclobutene monomer according to any one of claims 1-2, comprising the following steps: (1) In the presence of titanium tetrachloride, the compound shown in Formula II and the compound shown in Formula III undergo a McMurray coupling reaction in a dry solvent under the action of a reducing agent to obtain the compound shown in Formula IV. In Equation II, R1 and R2 are defined in the same way as in Equation I; In Equation III, R3 and R4 are defined in the same way as in Equation I; In Equation IV, the definitions of R1, R2, R3, and R4 are the same as in Equation I; (2) Under the action of an inorganic base, the compound shown in Formula IV is subjected to Williamson etherification reaction with 1-bromo-benzocyclobutene or 1-chloro-benzocyclobutene in an inert solvent to obtain the tetraphenylethylene-functionalized benzocyclobutene monomer.

4. The method of claim 3, wherein: The molar ratio of the compound shown in Formula II to the compound shown in Formula III is 1:(1~1.5). The reducing agent is zinc powder; The molar ratio of titanium tetrachloride to the reducing agent is 1:2; The drying solvent is ultra-dry tetrahydrofuran; The McMurray coupling reaction is carried out at a temperature of 70-80°C for 10-12 hours. The McMurray coupling reaction takes place in an anaerobic environment; The inorganic base is potassium carbonate, sodium carbonate, cesium carbonate, potassium hydroxide, or sodium hydroxide; The molar ratio of the compound shown in Formula IV to the 1-bromo-benzocyclobutene or 1-chloro-benzocyclobutene is 1:(2.2~3). The inert solvent is ultra-dry dimethyl sulfoxide, ultra-dry N,N-dimethylformamide, or ultra-dry N,N-dimethylacetamide; The Williamson etherification reaction was carried out at a temperature of 50-55 °C for 10-12 h. The Williamson etherification reaction was carried out in an anaerobic environment.

5. A tetraphenylethylene-functionalized benzocyclobutene resin, the structural formula of which is shown in Formula V: In formula V, R1, R2, R3, and R4 are each independently selected from hydrogen, C1-C8 alkyl, fluorine, phenyl, vinyl, trifluoropropyl, or perfluorooctyl; n is any integer from 3 to 100.

6. A tetraphenylethylene-functionalized benzocyclobutene resin, obtained by heating the tetraphenylethylene-functionalized benzocyclobutene monomer as described in claim 1 or 2 in an inert solvent and then crosslinking and curing it.

7. The tetraphenylethylene-functionalized benzocyclobutene resin according to claim 6, characterized in that: The inert solvent is selected from toluene, o-xylene, 1,3,5-trimethylbenzene, N,N-dimethylformamide, or N,N-dimethylacetamide; The cross-linking and curing are carried out in a vacuum environment; The heating is a gradient temperature increase under the following conditions: 150 ℃ / 1h, 160 ℃ / 1h, 170 ℃ / 3h.

8. A tetraphenylethylene-functionalized benzocyclobutene prepolymer, obtained by prepolymerization of the tetraphenylethylene-functionalized benzocyclobutene monomer as described in claim 1 or 2 in an inert solvent under heating conditions.

9. The tetraphenylethylene-functionalized benzocyclobutene prepolymer according to claim 8, characterized in that: The inert solvent is selected from toluene, o-xylene, 1,3,5-trimethylbenzene, N,N-dimethylformamide, or N,N-dimethylacetamide; The heating temperature is 120~150 ℃, and the time is 20~36h.

10. The use of the tetraphenylethylene-functionalized benzocyclobutene resin of any one of claims 5-7 or the tetraphenylethylene-functionalized benzocyclobutene prepolymer of claim 8 or 9 as an encapsulation material or interlayer positioning material.

11. A photoresist, characterized in that, It is made from a composition comprising the tetraphenylethylene-functionalized benzocyclobutene prepolymer as described in claim 8 or 9, a photosensitizer, and an organic solvent.

12. The photoresist according to claim 11, characterized in that: The weight proportions of each component are as follows: The tetraphenylethylene-functionalized benzocyclobutene prepolymer is 1-1.5 parts; The photosensitizer is 0.03 to 0.3 parts; The organic solvent is 5 to 50 parts.

13. The photoresist according to claim 11 or 12, characterized in that: The photosensitizer is an azide-based organic compound, with the structural formula shown below: The organic solvent is toluene, o-xylene, mesitylene, dichloromethane, chloroform, or tetrahydrofuran.

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