A preparation method for a novel low dielectric constant copper clad laminate adhesive

Abstract

The present invention belongs to the technical field of 5G copper clad laminate production, and particularly relates to a method for preparing a novel low dielectric constant copper clad laminate glue. In the preparation process of the glue, the present invention can effectively improve the curing behavior, heat resistance and high-frequency dielectric properties of the composite resin by using a low dielectric constant resin (benzoxazine resin modified by nano C60 material) introducing C60 nanoparticles; adding a low dielectric constant resin to a common high heat-resistant system can effectively reduce the dielectric constant of the copper clad laminate and improve electrical properties; the resin used in the present invention has low water absorption, and the obtained semi-cured sheet is not easy to bond, and the copper clad laminate has a low water absorption rate, which effectively prevents the occurrence of bursting during PCB production; using a phosphorus-containing flame retardant, it can be ensured that the flame retardant reaches the V0 level, avoiding the use of bromine-containing epoxy resin, and meeting environmental protection requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of 5G copper clad laminate production, and specifically relates to a method for preparing a novel low dielectric constant copper clad laminate adhesive. Background Art

[0002] With the development of a new generation of high-density and high-speed integrated circuits, there is an urgent need to design and develop low-dielectric copper-clad laminates as support. The high-frequency development of electronic equipment is an inevitable development trend, especially in the fields of wireless networks and satellite communications. Information products will inevitably move towards high-frequency, and communication products will also move towards the standardization of voice, video and data with large capacity and high speed wireless transmission. Therefore, the development of a new generation of electronic products requires high-frequency substrates.

[0003] The specific requirements for high-frequency substrates include: (1) the dielectric constant must be small and sufficiently stable; (2) the dielectric loss must be small; (3) it must have a low thermal expansion coefficient; (4) it must have an extremely low water absorption rate; (5) other heat resistance, chemical resistance, impact strength, peel strength, etc. must also be good; (6) halogen-free and lead-free requirements must be given priority. Summary of the invention

[0004] In view of the deficiencies in the above-mentioned prior art, the present invention provides a method for preparing a novel low dielectric constant copper clad laminate adhesive. By adding a specific benzoxazine resin and using the adhesive in the method, the dielectric constant (10G) of the copper clad laminate prepared can reach as low as 4.08, and it is suitable for halogen-free and lead-free processes. The copper clad laminate has extremely low water absorption and thermal expansion coefficient, and meets the use requirements of medium-loss high-frequency boards.

[0005] The specific technical solutions of the present invention are as follows:

[0006] A method for preparing a novel low dielectric constant copper clad laminate adhesive comprises the following steps:

[0007] (1) Preparation of a prepreg: by weight, 10 to 40 parts of epoxy resin, 10 to 30 parts of low dielectric constant resin, 5 to 30 parts of high heat resistant resin, 5 to 20 parts of multifunctional epoxy resin, 1 to 5 parts of curing agent, 1 to 5 parts of flame retardant, 10 to 35 parts of solvent, and 10 to 40 parts of filler are mixed and stirred to obtain a glue solution; electronic grade glass cloth is impregnated in the glue solution and baked at 150 to 200° C. for 2 to 15 minutes to obtain a prepreg;

[0008] (2) Using multiple prepregs obtained in step (1), both top and bottom of the prepregs are covered with copper foils, and pressed to obtain copper-clad laminates.

[0009] Furthermore, the epoxy resin is one or more of bisphenol A type, phosphorus-containing epoxy, polyphenol glycidyl ether type, aliphatic glycidyl ether type, glycidyl ester type, glycidyl amine type or epoxidized olefin compound.

[0010] Furthermore, the low dielectric constant resin is a benzoxazine resin modified by a nano-C60 material, and the benzoxazine resin modified by a nano-C60 material is obtained by curing nano-C60 and a benzoxazine resin.

[0011] Furthermore, the high heat-resistant resin is one or more of naphthol-type bisphenol A resin, MDI-modified phenolic resin, bismaleimide resin, polyphenylene ether resin, polyimide resin or aminophenol epoxy resin.

[0012] Furthermore, the multifunctional epoxy resin is tetraphenyl glycidyl ether ethane resin or triphenyl glycidyl ether methane resin.

[0013] Furthermore, the curing agent is one or more of phenol-type phenolic resin, o-cresol-type phenolic resin, BPA-type phenolic resin, linear bisphenol A phenolic resin, phosphorus-containing phenolic resin, and styrene maleic anhydride.

[0014] Furthermore, the flame retardant is one or more of phosphate ester, polymer phosphate ester, organic phosphorus salt and phosphorus essence.

[0015] Furthermore, the solvent is one or more of acetone, butanone, cyclohexanone or dimethylformamide.

[0016] Furthermore, the filler is one or more of aluminum oxyhydroxide, nano silicon dioxide, high-purity magnesium oxide, talcum powder or barium sulfate.

[0017] Furthermore, the prepreg obtained in step (1) has a glue content of 52-58% and a fluidity of 20-35%.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) In the process of preparing the glue, the present invention uses a benzoxazine resin modified with a nano C60 material, which effectively improves the curing behavior, heat resistance and high-frequency dielectric properties of the composite resin, significantly reduces the dielectric constant of the copper clad laminate, and has extremely low water absorption and thermal expansion coefficient, thereby enhancing dimensional stability;

[0020] (2) The present invention adds a low dielectric constant resin to a common high heat resistant system to effectively reduce the dielectric constant of the copper clad laminate and improve the electrical performance;

[0021] (3) The resin used in the present invention has low water absorption, the obtained prepreg is not easy to bond, and the copper clad laminate has a low water absorption rate, which effectively prevents the occurrence of board explosion during the PCB production process;

[0022] (4) The present invention uses a phosphorus-containing flame retardant to ensure that the flame retardancy reaches V0 level, avoids the use of bromine-containing epoxy resin, and meets environmental protection requirements. DETAILED DESCRIPTION

[0023] The principles and features of the present invention are described below in conjunction with examples. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. The measurement units used are parts by weight.

[0024] Preparation Example

[0025] The preparation method of benzoxazine resin modified by nano C60 material is as follows:

[0026] Nano-C60 is carboxylated using a NaOH solution, and benzoxazine which can generate phenolic hydroxyl groups through a self-ring-opening reaction is added, and the nano-C60 containing carboxyl groups and the benzoxazine containing phenolic hydroxyl groups are fully ground, wherein the mass percentage concentration of the nano-C60 is 10%, and the mass percentage concentration of the benzoxazine is 90%. After sufficient grinding, the solvent and water are removed, and the mixture is cured at 190° C. for 6 hours to obtain a benzoxazine resin modified with nano-C60.

[0027] Example 1

[0028] A method for preparing a novel low dielectric constant copper clad laminate adhesive comprises the following steps:

[0029] (1) Preparation of prepreg: by weight, 20 parts of bisphenol A epoxy resin, 10 parts of phosphorus-containing epoxy resin, 20 parts of benzoxazine resin modified by nano C60 material, 5 parts of MDI (diphenylmethane diisocyanate) modified phenolic resin, 5 parts of tetraphenylglycidyl ether ethane resin, 3 parts of phenolic phenolic resin, 2 parts of phosphorus essence, 20 parts of nano silicon dioxide, and 20 parts of dimethylformamide were mixed and stirred to obtain a glue solution; electronic grade glass cloth was immersed in the above glue solution, and baked at 175° C. for 6 minutes to obtain a prepreg with a glue content of 53% and a fluidity of 28%;

[0030] (2) Using 6 prepregs obtained in step (1), each of which was covered with a copper foil (15 μm) on the top and bottom, the laminate was pressed at 210° C. and 3.5 kPa for 220 min to obtain a copper clad laminate.

[0031] Example 2

[0032] A method for preparing a novel low dielectric constant copper clad laminate adhesive comprises the following steps:

[0033] (1) Preparation of a prepreg: by weight, 30 parts of a polyphenol glycidyl ether epoxy resin, 5 parts of a phosphorus-containing epoxy resin, 10 parts of a benzoxazine resin modified with a nano-C60 material, 5 parts of a naphthol-type bisphenol A resin, 5 parts of a triphenyl glycidyl ether methane resin, 1 part of a phenol-type phenolic resin, 2 parts of styrene maleic anhydride, 2 parts of phosphine, 20 parts of nano-silica, 10 parts of butanone, and 10 parts of dimethylformamide were mixed and stirred to obtain a glue solution; an electronic grade glass cloth was immersed in the above glue solution, and dried at 185° C. for 5 minutes to obtain a prepreg with a glue content of 56% and a fluidity of 26%;

[0034] (2) Using 6 prepregs obtained in step (1), each of which was covered with a copper foil (15 μm) on the top and bottom, the laminate was pressed at 210° C. and 3.5 kPa for 220 min to obtain a copper clad laminate.

[0035] Comparative Example

[0036] A method for preparing a novel low dielectric constant copper clad laminate adhesive comprises the following steps:

[0037] (1) Preparation of a prepreg: by weight, 30 parts of a polyphenol glycidyl ether epoxy resin, 5 parts of a phosphorus-containing epoxy resin, 10 parts of a benzoxazine resin (not modified with C60), 5 parts of a naphthol bisphenol A resin, 5 parts of a triphenyl glycidyl ether methane resin, 1 part of a phenol-type phenolic resin, 2 parts of styrene maleic anhydride, 2 parts of phosphine, 20 parts of nano-silica, 10 parts of butanone, and 10 parts of dimethylformamide were mixed and stirred to obtain a glue solution; electronic grade glass cloth was immersed in the above glue solution and dried at 185° C. for 5 min to obtain a prepreg with a glue content of 55% and a fluidity of 25%;

[0038] (2) Using 6 prepregs obtained in step (1), each of which was covered with a copper foil (15 μm) on the top and bottom, the laminate was pressed at 210° C. and 3.5 kPa for 220 min to obtain a copper clad laminate.

[0039] Test method description:

[0040] (1) Glass transition temperature (DSC): Determined by differential scanning calorimetry (DSC) in accordance with the method specified in IPC-TM-6502.4.25.

[0041] (2) Thermal delamination time T-288: Measured using a thermomechanical analyzer in accordance with the method specified in IPC-TM-650 2.4.24.1.

[0042] (3) Td thermal decomposition temperature: measured by thermogravimetric analysis according to the method specified in IPC-TM-650 2.4.24.6.

[0043] (4) Flammability: Measured according to the method specified in UL94.

[0044] (5) Z-axis CTE: measured using a thermomechanical analyzer according to the method specified in IPC-TM-650 2.4.24.

[0045] (6) Water absorption: Measured according to the method specified in IPC-TM-650 2.6.2.1.

[0046] (7) Dielectric constant (Dk): Measured by the parallel plate capacitance method according to the method specified in IPC-TM-650 2.5.5.9.

[0047] (8) Dielectric loss (Df): Measured using a parallel plate capacitor method in accordance with the method specified in IPC-TM-650 2.5.5.9.

[0048] The experimental data of the copper clad laminate performance test of Examples 1 and 2 and the comparative example are shown in Table 1.

[0049] Table 1 Experimental data of copper clad laminate performance test of Examples 1, 2 and Comparative Example

[0050]

[0051]

[0052] By comparing the test experimental data in Table 1, it can be seen that in the preparation process of the glue, the use of benzoxazine resin modified with nano C60 material significantly reduces the dielectric constant (10G) of the copper clad laminate to a minimum of 4.08; and the copper clad laminate has good heat resistance and extremely low water absorption, which meets the use requirements of medium-loss high-frequency boards; the flame retardancy reaches V0 level, avoiding the use of bromine-containing epoxy resin and meeting environmental protection requirements.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a novel low dielectric constant copper clad laminate adhesive, characterized in that: The following steps are involved: (1) Preparation of prepreg: by weight, 10-40 parts of epoxy resin, 10-30 parts of low dielectric constant resin, 5-30 parts of high heat resistant resin, 5-20 parts of multifunctional epoxy resin, 1-5 parts of curing agent, 1-5 parts of flame retardant, 10-35 parts of solvent and 10-40 parts of filler are mixed and stirred to obtain a glue solution; electronic grade glass cloth is impregnated in the glue solution and baked at 150-200° C. for 2-15 minutes to obtain a prepreg; the obtained prepreg has a glue content of 52-58% and a fluidity of 20-35%; (2) using a plurality of prepregs obtained in step (1), both top and bottom of which are covered with copper foil, and pressing to obtain a copper clad laminate; Wherein, the flame retardant is a phosphate ester and / or an organic phosphorus salt, the low dielectric constant resin is a benzoxazine resin modified by a nano-C60 material, and the benzoxazine resin modified by a nano-C60 material is obtained by curing nano-C60 and a benzoxazine resin; The preparation method of the benzoxazine resin modified by the nano C60 material is as follows: Nano-C60 is carboxylated using a NaOH solution, and benzoxazine which can generate phenolic hydroxyl groups by its own ring-opening reaction is added, and the nano-C60 containing carboxyl groups and the benzoxazine containing phenolic hydroxyl groups are fully ground, wherein the mass percentage concentration of nano-C60 is 10%, and the mass percentage concentration of benzoxazine is 90%. After sufficient grinding, the solvent and water are removed, and the mixture is cured at 190° C. for 6 hours to obtain a benzoxazine resin modified with nano-C60.

2. The method for preparing a novel low dielectric constant copper clad laminate adhesive according to claim 1, characterized in that: The epoxy resin is one or more of bisphenol A type, phosphorus-containing epoxy, polyphenol glycidyl ether type, aliphatic glycidyl ether type, glycidyl ester type, glycidyl amine type or epoxidized olefin compound.

3. The method for preparing a novel low dielectric constant copper clad laminate adhesive according to claim 1, characterized in that: The high heat-resistant resin is one or more of naphthol-type bisphenol A resin, MDI-modified phenolic resin, bismaleimide resin, polyphenylene ether resin, polyimide resin or aminophenol epoxy resin.

4. The method for preparing a novel low dielectric constant copper clad laminate adhesive according to claim 1, characterized in that: The multifunctional epoxy resin is tetraphenyl glycidyl ether ethane resin or triphenyl glycidyl ether methane resin.

5. The method for preparing a novel low dielectric constant copper clad laminate adhesive according to claim 1, characterized in that: The curing agent is one or more of phenol-type phenolic resin, o-cresol-type phenolic resin, BPA-type phenolic resin, linear bisphenol A phenolic resin, phosphorus-containing phenolic resin, and styrene maleic anhydride.

6. The method for preparing a novel low dielectric constant copper clad laminate adhesive according to claim 1, characterized in that: The solvent is one or more of acetone, butanone, cyclohexanone or dimethylformamide; the filler is one or more of aluminum hydroxide, nano silicon dioxide, high-purity magnesium oxide, talcum powder or barium sulfate.

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