Copper clad laminate for high-frequency circuits, preparation method thereof, and organic dielectric slurry

Abstract

The present invention discloses a copper clad plate for high-frequency circuits, a preparation method, and an organic medium slurry. The preparation method comprises the following steps: adding hydrogenated styrene-butadiene-styrene copolymer, polyvinylcyclohexane derivatives containing aromatic groups, silicon dioxide powder, and dicumyl peroxide to an organic solvent, stirring until completely dissolved, and obtaining an organic medium slurry; soaking glass fiber cloth in the organic medium slurry until the glass fiber cloth is coated with the organic medium slurry to obtain a glass fiber cloth prepreg; placing multiple layers of glass fiber cloth prepreg between two layers of copper foil, and obtaining a copper clad plate for high-frequency circuits after hot pressing. The preparation method of the present invention has simple process, low cost, low dielectric loss of the copper clad plate, high glass transition temperature, low thermal expansion coefficient, and various indicators substantially meet the use requirements of the copper clad plate for high-frequency circuits.

Description

Technical Field

[0001] The invention relates to the technical field of copper-clad laminates for high-frequency circuits, in particular to a copper-clad laminate for high-frequency circuits, a preparation method thereof, and an organic dielectric slurry. Background Art

[0002] With the advancement of AI and autonomous driving, demands for data transmission and communication speeds are increasing. For example, the 6G technology currently under development will utilize terahertz (THz), or submillimeter frequency bands, with transmission capabilities expected to increase 100 times compared to 5G. Higher communication frequencies increase the requirements for printed circuit boards (PCBs). These requirements primarily include lower dielectric loss (Df), lower dielectric constant (Dk), higher reliability, higher heat resistance, and an extremely low coefficient of thermal expansion (CTE). Of particular importance is lower Df.

[0003] The manufacturing process of integrated circuits requires high temperatures of over 400 degrees, and the temperatures required in subsequent processing are even higher. Copper wiring processes, such as electroplating or chemical reduction, can be completed below 250 degrees, but to ensure that the copper deposition is dense and free of pores, annealing treatment is required at 400-450 degrees, so the material is required to have excellent heat resistance and a very high glass transition temperature. For example, the heat resistance of polyimide and polybenzoxazine can meet the requirements, but the Dk and Df are too high to meet the requirements of 5G and above communications. Bis(vinylbenzene)ethane (BVPE) is a hydrocarbon resin currently used in industry for curing copper clad laminates. Its glass transition temperature Tg is lower than 200°C, and its heat resistance needs to be improved.

[0004] In addition, due to the huge amount of circuit boards used, cost control of the resin used is very important. At this stage, only simple deep processing using industrial raw materials can meet the market's low-cost needs. Summary of the Invention

[0005] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the object of the present invention is to provide a method for preparing a copper clad laminate for high-frequency circuits, which uses industrial products 1,2,4-trivinylcyclohexane and dibromoarene as raw materials to prepare an organic medium, with a simple process and low cost. The prepared copper clad laminate for high-frequency circuits has low dielectric loss Df, high glass transition temperature Tg, and low thermal expansion coefficient, and all indicators basically meet the use requirements of copper clad laminates for high-frequency circuits.

[0006] Another object of the present invention is to provide a copper clad laminate for high-frequency circuits.

[0007] Another object of the present invention is to provide an organic dielectric slurry for preparing copper-clad laminates for high-frequency circuits.

[0008] Another object of the present invention is to provide a polyvinylcyclohexane derivative containing an aromatic group for use in preparing copper-clad laminates for high-frequency circuits.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] The present invention provides a method for preparing a copper clad laminate for high-frequency circuits, comprising the following steps:

[0011] 25-35 parts of hydrogenated styrene-butadiene-styrene copolymer, 65-75 parts of aromatic-containing polyvinylcyclohexane derivative, 15-25 parts of silicon dioxide powder, and 0.8-1.2 parts of dicumyl peroxide are added to an organic solvent and stirred until completely dissolved to obtain an organic medium slurry;

[0012] soaking the glass fiber cloth in the organic medium slurry until the glass fiber cloth is covered by the organic medium slurry to obtain a glass fiber cloth prepreg;

[0013] Multiple layers of glass fiber cloth prepreg are placed between two layers of copper foil and hot pressed to obtain a copper clad laminate for high-frequency circuits;

[0014] Wherein, the polyvinyl cyclohexane derivative containing an aromatic group has the following structure:

[0015]

[0016] Wherein Ar is an aromatic hydrocarbon;

[0017] TVCH is triethylene cyclohexane, and its structure is one of the following structures:

[0018]

[0019] TVCH is connected to the aromatic hydrocarbon at the dotted line.

[0020] Preferably, the aromatic hydrocarbon is benzene, biphenyl, terphenyl, fluorene, naphthalene or anthracene.

[0021] Preferably, the aromatic hydrocarbon has one of the following structures:

[0022]

[0023] Preferably, the preparation of the aromatic-containing polyvinylcyclohexane derivative is as follows:

[0024] Potassium phosphate, 1,2,4-trivinylcyclohexane, dibromoarene, N,N-dimethylformamide, palladium acetate, and triphenylphosphine are added; the reaction is carried out at 120-140° C. in an argon atmosphere for 20-48 hours; the product is precipitated, centrifuged, dried, column-filtered, spin-dried, and pumped dry with a heated oil pump to 115-125° C., followed by recrystallization. The product is then pumped in a vacuum drying oven at 75-85° C. using a diaphragm pump for 0.8-1.2 hours to obtain an aromatic-containing polyvinylcyclohexane derivative, TVCH-Ar-TVCH.

[0025] Preferably, the molar ratio of the 1,2,4-trivinylcyclohexane to the dibromoarene is (1.8-2.2):1.

[0026] Preferably, the amount of palladium acetate added is 0.8-1.0% of the molar amount of dibromoarene; and the amount of triphenylphosphine added is 1-5% of the molar amount of dibromoarene.

[0027] Preferably, the hot pressing is specifically: hot pressing at 205-215° C. and 2.8-3.2 MPa.

[0028] The present invention also provides a copper-clad laminate for high-frequency circuits, which is prepared by the method for preparing the copper-clad laminate for high-frequency circuits.

[0029] The present invention also provides an organic medium slurry, which comprises the following components dissolved in an organic solvent, in parts by weight:

[0030]

[0031] Preferably, the peroxidation initiator is dicumyl peroxide;

[0032] The aromatic-containing polyvinylcyclohexane derivative has the following structure:

[0033]

[0034] Wherein Ar is an aromatic hydrocarbon;

[0035] TVCH is triethylene cyclohexane, and its structure is one of the following structures:

[0036]

[0037] TVCH is connected to the aromatic hydrocarbon at the dotted line.

[0038] The present invention also provides an aromatic-containing polyvinylcyclohexane derivative having the following structure:

[0039]

[0040] Wherein Ar is an aromatic hydrocarbon;

[0041] TVCH is triethylene cyclohexane, and its structure is one of the following structures:

[0042]

[0043] TVCH is connected to the aromatic hydrocarbon at the dotted line.

[0044] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0045] (1) The method for preparing a copper-clad laminate for high-frequency circuits of the present invention uses industrial products 1,2,4-triethylenecyclohexane and dibromoarene as raw materials to prepare the organic medium therein, which has a simple process and low cost.

[0046] (2) The copper clad laminate for high-frequency circuits of the present invention has a low dielectric constant, a dielectric loss Df at 10 GHz as low as 0.00101, a glass transition temperature Tg as high as 277°C, and a low thermal expansion coefficient. All indicators basically meet the use requirements of the copper clad laminate.

[0047] (3) The copper-clad laminate for high-frequency circuits of the present invention exhibits stable dielectric properties, with dielectric loss increasing by only 4% after one hour of operation and remaining unchanged from one to 24 hours. In contrast, the best-performing currently available material, ethylenediphenylethylene (BVPE), exhibits a dielectric loss increase of 6.3% after one hour and a further 7.6% from one to 24 hours, for a total increase of 13.9%.

[0048] (4) The aromatic-containing polyvinylcyclohexane derivatives of the present invention have an all-carbon-hydrogen structure and possess extremely low Dk and Df. They contain a benzene ring and have higher heat resistance than all-fatty / alicyclic compounds.

[0049] (5) The aromatic-containing polyvinylcyclohexane derivative of the present invention contains at least four vinyl functional groups and is asymmetric, so that a higher degree of crosslinking can be obtained by thermal curing, thereby having higher dielectric properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is the NMR spectrum of the phenyl-containing polyvinylcyclohexane derivative TVCH-Ph-TVCH of Example 1 of the present invention.

[0051] Figure 2 The test results of the thermal stability of the copper clad laminate of Example 1 of the present invention were tested using DMA (dynamic mechanical analysis); the blue curve in the figure represents the storage modulus; the green curve represents the loss modulus; and the red curve represents the loss tangent.

[0052] Figure 3 The thermal stability test results of the copper clad laminate of Example 1 of the present invention are tested using TMA (thermomechanical analysis).

[0053] Figure 4 This is the thermogravimetric analysis test result of the phenyl-containing polyvinylcyclohexane derivative TVCH-Ph-TVCH of Example 1 of the present invention.

[0054] Figure 5 This is the NMR spectrum of the phenyl-containing polyvinylcyclohexane derivative TVCH-BP-TVCH of Example 2 of the present invention.

[0055] Figure 6 The test results of the thermal stability of the copper clad laminate of Example 2 of the present invention using DMA (dynamic mechanical analysis) are shown; the blue curve in the figure represents the storage modulus; the green curve represents the loss modulus; and the red curve represents the loss tangent.

[0056] Figure 7 The thermal stability test results of the copper clad laminate of Example 2 of the present invention are tested using TMA (thermomechanical analysis).

[0057] Figure 8 This is the thermogravimetric analysis test result of the phenyl-containing polyvinylcyclohexane derivative TVCH-BP-TVCH according to Example 2 of the present invention. DETAILED DESCRIPTION

[0058] The present invention will be further described in detail below with reference to the examples, but the embodiments of the present invention are not limited thereto.

[0059] Example 1

[0060] The preparation reaction formula of the aromatic-containing polyvinylcyclohexane derivative of this embodiment is as follows:

[0061]

[0062] The raw materials used are: trivinylcyclohexane (8 mmol, molecular weight 162, 1.296 g), p-dibromobenzene (4 mmol, molecular weight 236, 0.944 g), palladium acetate (0.018 mmol, molecular weight 224.5, 8.08 mg, 0.9 mol% of bromobenzene), potassium phosphate (11.2 mmol, molecular weight 212, 2.37 g), triphenylphosphine (0.024 mmol, molecular weight 262, 6.3 mg), and 8 ml of N,N-dimethylformamide (DMF).

[0063] The process is as follows: 2.37 g potassium phosphate, 6.3 mg triphenylphosphine (molecular weight 262), 1.29 g trivinylcyclohexane (8 mmol), 0.94 g 1,4-dibromobenzene (4 mmol), 8.08 mg palladium acetate (0.018 mmol), and 8 ml DMF were added to a flask, replaced with an argon atmosphere, and reacted at 140°C for 48 hours. Water was added to precipitate the product, which was then extracted with 40 ml toluene. The resulting toluene solution was centrifuged, dried over anhydrous magnesium sulfate, and rapidly passed through a toluene-based silica gel column. The solution was then spin-dried and the toluene was removed using a 120°C electric heating mantle oil pump to yield a viscous yellow-red substance. The product was recrystallized from 8 ml methanol overnight, the methanol was decanted, and the product was placed in a vacuum drying oven at 80°C with a diaphragm pump for one hour. The final product, 1.325 g, was obtained with a yield of 82.8%. The main component was TVCH-Ph-TVCH, with a small amount of oligomers present, which did not affect its use.

[0064] The NMR spectrum of the phenyl-containing polyvinylcyclohexane derivative TVCH-Ph-TVCH of this embodiment is as follows: Figure 1 shown.

[0065] The above-mentioned phenyl-containing polyvinylcyclohexane derivative TVCH-Ph-TVCH and 1% dicumyl peroxide were placed in a test tube and heated to 220°C under nitrogen atmosphere for 2 hours to obtain a cross-linked polyvinylcyclohexane derivative. A small amount of the cured sample was subjected to thermogravimetric analysis. The results were as follows: Figure 4 As shown, 5% thermal weight loss occurs at 327°C and 10% thermal weight loss occurs at 410°C.

[0066] The copper clad plate for high-frequency circuits of this embodiment is prepared as follows:

[0067] 30 g of hydrogenated styrene-butadiene-styrene copolymer (SEBS), 70 g of phenyl-containing polyvinylcyclohexane derivative TVCH-Ph-TVCH, 20 g of silica powder and 1 g of dicumyl peroxide (DCP) were added to 300 ml of toluene and stirred at room temperature until completely dissolved.

[0068] Surface-modified glass fiber cloth (10 cm x 10 cm) was immersed in the organic medium slurry prepared above until it was coated. It was then air-dried at 80°C for 15 minutes until the surface was dry. Two to ten layers of glass fiber cloth prepreg were placed between two layers of copper foil and placed in a hot press. The prepreg was pressed at 210°C and a pressure of 10 MPa for two hours. Finally, the hot-pressed laminate was cooled to room temperature to obtain the copper-clad laminate sample.

[0069] The copper clad laminate samples were cut into standard samples for thermal stability analysis. The Tg glass transition temperature of the DMA (dynamic mechanical analysis) single cantilever test was 277°C. Figure 2 shown.

[0070] After the copper clad laminate samples were cut into standard samples, thermal stability analysis was performed. The Tg glass transition temperature tested by TMA (thermomechanical analysis) was 260°C, and the thermal expansion coefficient CTE was 260ppm / °C. Figure 3 shown.

[0071] Example 2

[0072] The preparation reaction formula of the aromatic-containing polyvinylcyclohexane derivative of this embodiment is as follows:

[0073]

[0074] The procedure is as follows: 2.37 g potassium phosphate, 6.3 mg triphenylphosphine, 1.29 g trivinylcyclohexane (8 mmol), 1.25 g 4,4-dibromobiphenyl (4 mmol), 8.08 mg palladium acetate (0.018 mmol), and 8 ml DMF were added to a flask, replaced with an argon atmosphere, and reacted at 140°C for 48 hours. Water was added to precipitate the product, which was then extracted with 40 ml toluene. The resulting toluene solution was centrifuged and dried over anhydrous magnesium sulfate. The solution was then rapidly passed through a toluene-silica gel column, spin-dried, and the toluene was removed using a 120°C electric heating mantle oil pump to yield a viscous yellow-red substance. This was recrystallized from 8 ml methanol overnight, the methanol was decanted, and the product was placed in a vacuum drying oven at 80°C with a diaphragm pump for one hour. The final yield was 1.6328 g, with a yield of 85.98%. The main component was TVCH-BP-TVCH, with a small amount of oligomers present, which did not affect its use. The NMR spectrum of the phenyl-containing polyvinylcyclohexane derivative TVCH-BP-TVCH of this embodiment is shown in Figure 5 .

[0075] The above polyvinylcyclohexane derivative TVCH-BP-TVCH and 1% dicumyl peroxide were placed in a test tube and heated to 220°C under nitrogen atmosphere for 2 hours to obtain a cross-linked polyvinylcyclohexane derivative. A small amount of the cured sample was subjected to thermogravimetric analysis. The results were as follows: Figure 8 As shown, 5% thermal weight loss occurs at 425°C and 10% thermal weight loss occurs at 448°C.

[0076] The copper clad plate for high-frequency circuits of this embodiment is prepared as follows:

[0077] 30 g of hydrogenated styrene-butadiene-styrene copolymer (SEBS), 70 g of biphenyl-containing polyvinylcyclohexane derivative TVCH-BP-TVCH, 20 g of silica powder and 1 g of dicumyl peroxide (DCP) were added to 300 ml of toluene and stirred at room temperature until completely dissolved.

[0078] Surface-modified glass fiber cloth (10 cm x 10 cm) was immersed in the organic medium slurry prepared above until it was coated. It was then air-dried at 80°C for 15 minutes until the surface was dry. Two to ten layers of glass fiber cloth prepreg were placed between two layers of copper foil and placed in a hot press. The prepreg was pressed at 210°C and a pressure of 10 MPa for two hours. Finally, the hot-pressed laminate was cooled to room temperature to obtain the copper-clad laminate sample.

[0079] The copper clad laminate samples were cut into standard samples for thermal stability analysis. The Tg glass transition temperature of the DMA (dynamic mechanical analysis) single cantilever test was 271°C. Figure 6 shown.

[0080] The copper clad laminate samples were cut into standard samples and then subjected to thermal stability analysis. The TMA (thermomechanical analysis) test was as shown in the attached Figure 7 shown.

[0081] The peel strength, thermogravimetric analysis (Tg), thermal expansion coefficient, dielectric loss at 10 GHz (Df), dielectric constant at 10 GHz (Dk), and storage modulus test results of the copper clad laminate samples prepared in this embodiment are shown in Table 1.

[0082] Comparative Example

[0083] The organic dielectric slurry is prepared using the best low-dielectric hydrocarbon resin currently available, diphenylethylene ethane (BVPE). The structure of diphenylethylene ethane is as follows:

[0084]

[0085] The preparation of the copper clad plate for high frequency circuit of this comparative example is as follows:

[0086] 30 g of hydrogenated styrene-butadiene-styrene copolymer (SEBS), 70 g of biphenylethylene (BVPE), 20 g of silica powder and 1 g of dicumyl peroxide (DCP) were added to 300 ml of toluene and stirred at room temperature until completely dissolved.

[0087] Surface-modified glass fiber cloth (10 cm x 10 cm) was immersed in the slurry prepared above until it was coated with the solution. It was then air-dried at 80°C for 15 minutes until the surface was dry. Two to ten layers of glass fiber cloth prepreg were placed between two layers of copper foil and placed in a hot press. The prepreg was pressed at 210°C and a pressure of 10 MPa for two hours. Finally, the hot-pressed laminate was cooled to room temperature to obtain the copper-clad laminate sample.

[0088] The peel strength, thermogravimetric (Tg), thermal expansion coefficient, dielectric loss at 10 GHz (Df), dielectric constant at 10 GHz (Dk), and storage modulus test results of the copper clad laminate samples prepared in this comparative example are shown in Table 1.

[0089] Table 1 Comparison of performance of copper clad laminate samples of Examples 1-2 and Comparative Example

[0090]

[0091] As can be seen from Table 1, compared with BVPE, TVCH-Ph-TVCH and TVCH-BP-TVCH have higher glass transition temperatures, which can be seen from the test results of dynamic mechanical analysis (DMA). The glass transition temperatures Tg of BVPE, TVCH-Ph-TVCH and TVCH-BP-TVCH obtained by the single cantilever method are 190.55°C, 277.58°C, and 271.04°C, respectively, while the glass transition temperatures Tg obtained by the three-point bending method are 167.93°C, 246.17°C, and 246.77°C, respectively.

[0092] Table 1 shows that while the dielectric loss Df of TVCH-Ph-TVCH and TVCH-BP-TVCH is not as low as that of BVPE, their stability is very high. For example, TVCH-Ph-TVCH shows an immediate value of 0.00101, but its stability is even higher, reaching 0.00105 after one hour and remaining at 0.00105 after 24 hours. This means that the dielectric loss increases by only 4% after one hour and remains unchanged from one to 24 hours. In contrast, the best-performing diphenylethylene BVPE shows a 6.3% increase in dielectric loss after one hour and a further 7.6% increase from one to 24 hours, for a total increase of 13.9%.

[0093] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a copper clad laminate for high-frequency circuits, characterized in that: The following steps are involved: 25-35 parts of hydrogenated styrene-butadiene-styrene copolymer, 65-75 parts of aromatic-containing polyvinylcyclohexane derivative, 15-25 parts of silicon dioxide powder, and 0.8-1.2 parts of dicumyl peroxide are added to an organic solvent and stirred until completely dissolved to obtain an organic medium slurry; soaking the glass fiber cloth in the organic medium slurry until the glass fiber cloth is covered by the organic medium slurry to obtain a glass fiber cloth prepreg; Multiple layers of glass fiber cloth prepreg are placed between two layers of copper foil and hot pressed to obtain a copper clad laminate for high-frequency circuits; Wherein, the polyvinyl cyclohexane derivative containing an aromatic group has the following structure: wherein Ar is an aromatic hydrocarbon; the aromatic hydrocarbon is benzene, biphenyl, terphenyl, fluorene, naphthalene or anthracene; TVCH is triethylene cyclohexane, and its structure is one of the following structures: ； TVCH is connected to the aromatic hydrocarbon at the dotted line.

2. The method for preparing a copper clad laminate for high-frequency circuits according to claim 1, wherein: The aromatic hydrocarbon has one of the following structures: 。 3. The method for preparing a copper clad laminate for high-frequency circuits according to claim 1, wherein: The preparation of the aromatic-containing polyvinylcyclohexane derivative is as follows: Potassium phosphate, 1,2,4-trivinylcyclohexane, dibromoarene, N,N-dimethylformamide, palladium acetate, and triphenylphosphine are added; the reaction is carried out at 120-140°C in an argon atmosphere for 20-48 hours; the product is precipitated, centrifuged, dried, column-filtered, spin-dried, and pumped dry with a heated oil pump to 115-125°C before recrystallization. The product is then pumped in a vacuum drying oven at 75-85°C using a diaphragm pump for 0.8-1.2 hours to obtain an aromatic-containing polyvinylcyclohexane derivative.

4. The method for preparing a copper clad laminate for high-frequency circuits according to claim 3, wherein: The molar ratio of the 1,2,4-trivinylcyclohexane to the dibromoarene is (1.8-2.2):

1.

5. The method for preparing a copper clad laminate for high-frequency circuits according to claim 3, wherein: The amount of palladium acetate added is 0.8-1.0% of the molar amount of dibromoarene; the amount of triphenylphosphine added is 1%-5% of the molar amount of dibromoarene.

6. The method for preparing a copper clad laminate for high-frequency circuits according to claim 1, wherein: The hot pressing is specifically: hot pressing under the conditions of 205-215° C. and 2.8-3.2 MPa.

7. A copper clad laminate for high frequency circuits, characterized in that: The copper clad laminate is prepared by the method for preparing a copper clad laminate for high-frequency circuits according to any one of claims 1 to 6.

8. Organic medium slurry, characterized in that Calculated by weight, it includes the following components dissolved in an organic solvent: 25-35 parts of hydrogenated styrene-butadiene-styrene copolymer; 65-75 parts of polyvinylcyclohexane derivatives containing aromatic groups; 15-25 parts of silicon dioxide powder; 0.8~1.2 parts of peroxide initiator; The aromatic-containing polyvinylcyclohexane derivative has the following structure: wherein Ar is an aromatic hydrocarbon; the aromatic hydrocarbon is benzene, biphenyl, terphenyl, fluorene, naphthalene or anthracene; TVCH is triethylene cyclohexane, and its structure is one of the following structures: ； TVCH is connected to the aromatic hydrocarbon at the dotted line.

9. A polyvinylcyclohexane derivative containing an aromatic group, characterized in that: Has the following structure: wherein Ar is an aromatic hydrocarbon; the aromatic hydrocarbon is benzene, biphenyl, terphenyl, fluorene, naphthalene or anthracene; TVCH is triethylene cyclohexane, and its structure is one of the following structures: ； TVCH is connected to the aromatic hydrocarbon at the dotted line.

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