阅读说明：本技术 预浸料组合物、半固化片、电路基板和印制电路板 (Prepreg composition, prepreg, circuit board and printed circuit board ) 是由 魏俊麒 韩梦娜 董辉 任英杰 于 2020-06-05 设计创作，主要内容包括：本发明涉及一种预浸料组合物、半固化片、电路基板和印制电路板,所述预浸料组合物包括树脂和介电填料,所述介电填料的电导率小于等于450μS/cm。本发明的预浸料组合物中,通过控制介电填料的电导率,能够有效控制介电填料产生的游离态带电荷离子的数量。因此,基于该预浸料组合物制成的印制电路板在使用时,产生游离态的带电荷离子数量少,从而有效提高了印制电路板的耐离子迁移性能。(The invention relates to a prepreg composition, a prepreg, a circuit substrate and a printed circuit board, wherein the prepreg composition comprises resin and a dielectric filler, and the electrical conductivity of the dielectric filler is less than or equal to 450 mu S/cm. In the prepreg composition, the number of free charged ions generated by the dielectric filler can be effectively controlled by controlling the conductivity of the dielectric filler. Therefore, when the printed circuit board prepared from the prepreg composition is used, the number of the charged ions in a free state is small, and the ion migration resistance of the printed circuit board is effectively improved.)

1. A prepreg composition comprising a resin and a dielectric filler, wherein the dielectric filler has a conductivity of 450 [ mu ] S/cm or less.

2. The prepreg composition of claim 1, wherein a surface of the dielectric filler has a finish.

3. The prepreg composition of claim 2, wherein the modifier encapsulates the dielectric filler.

4. The prepreg composition of claim 2, wherein the material of the modifier comprises at least one of a surfactant, a titanate coupling agent, a silane coupling agent, a fluorosilane coupling agent, and an alkanolamine surface treatment agent.

5. The prepreg composition of claim 2, wherein the material of the modifier comprises at least one of a non-metal oxide, a non-metal nitride, and a non-metal sulfide.

6. The prepreg composition of claim 1, wherein a mass ratio of the resin to the dielectric filler is 100:60 to 100: 150.

7. The prepreg composition of claim 1, further comprising at least one of a curing agent, a coupling agent, and a co-crosslinking agent.

8. A prepreg comprising a reinforcing material and the prepreg composition of any one of claims 1 to 7 attached to the reinforcing material.

9. A circuit substrate comprising a dielectric layer and a conductive layer disposed on at least one surface of the dielectric layer, wherein the dielectric layer is formed by curing the prepreg according to claim 8.

10. A printed circuit board comprising the circuit substrate of claim 9.

Technical Field

The invention relates to the technical field of electronic industry, in particular to a prepreg composition, a prepreg, a circuit substrate and a printed circuit board.

Background

When the printed circuit board works in a charged mode under the high-temperature and high-humidity environment, the short circuit failure is caused by the ion migration (CAF) phenomenon of the Printed Circuit Board (PCB), and the damage is large.

There are many factors that affect PCB ion migration, including internal factors such as PCB design structure and material selection, and external factors such as processing, storage and working environment. In order to improve the ion migration resistance of the PCB, the conventional methods include optimizing the design of the PCB structure, preferably using ion migration resistant materials, adding ion traps, and strictly controlling the PCB processing procedure, however, these methods do not significantly improve the ion migration resistance of the PCB and risk causing PCB defects.

Disclosure of Invention

In view of the above, it is necessary to provide a prepreg composition, a prepreg, a circuit board, and a printed circuit board; the printed circuit board obtained based on the prepreg composition has strong ion migration resistance.

A prepreg composition comprising a resin and a dielectric filler, the dielectric filler having a conductivity of 450 [ mu ] S/cm or less.

In one embodiment, the surface of the dielectric filler has a modification.

In one embodiment, the modifier encapsulates the dielectric filler.

In one embodiment, the material of the modifier comprises at least one of a surfactant, a titanate coupling agent, a silane coupling agent, a fluorosilane coupling agent and an alcohol amine surface treatment agent.

In one embodiment, the material of the modifier comprises at least one of non-metal oxide, non-metal nitride and non-metal sulfide.

In one embodiment, the mass ratio of the resin to the dielectric filler is 100:60 to 100: 150.

In one embodiment, the prepreg composition further comprises at least one of a coupling agent and a co-crosslinking agent.

A prepreg comprises a reinforcing material and the prepreg composition attached to the reinforcing material.

A circuit substrate comprises a dielectric layer and a conducting layer arranged on at least one surface of the dielectric layer, wherein the dielectric layer is formed by curing the prepreg.

A printed circuit board comprises the circuit substrate.

In the prepreg composition, the number of free charged ions generated by the dielectric filler can be effectively controlled by controlling the conductivity of the dielectric filler. Therefore, when the PCB made of the prepreg composition is used, the number of charged ions generating free state is small, and the ion migration resistance of the PCB is effectively improved. Meanwhile, the PCB has excellent dielectric constant and dielectric loss, and the dielectric property range is adjustable.

Detailed Description

The prepreg composition, prepreg, circuit board and printed circuit board provided by the present invention will be further described below.

The applicant has found, through long-term and intensive research, that the dielectric filler is used as a processing aid in the production and processing processAnd for the reasons of agent, etc., a substance which can be hydrolyzed to generate free charged ions or a substance which can be corroded by acid/alkali to generate charged ions is inevitably remained on the surface. In addition, dielectric fillers of the borosilicate glass type (e.g., hollow glass microspheres) contain Na by themselves₂O、K₂O, CaO, the surface of the metal is easily corroded during use to generate free charged metal cations. Therefore, when the PCB is used, the number of free charged ions in the PCB is increased continuously under the influence of the environment, and further, the potential difference is increased continuously under the electrified condition, and finally, CAF failure occurs in the PCB.

In summary, the ability of the dielectric filler to generate the amount of free charged ions is a key factor in determining the amount of free charged ions inside the PCB, and thus determines the ion migration resistance of the PCB, and the conductivity of the dielectric filler is reflected in the ability of the dielectric filler to generate the amount of free charged ions.

To this end, according to a first aspect of the present invention, there is provided a prepreg composition comprising a resin and a dielectric filler, the dielectric filler having an electrical conductivity of 450. mu.S/cm or less.

The method for measuring the electrical conductivity of the dielectric filler of the present invention is as follows:

the method comprises the following steps:

respectively measuring 100mL of deionized water, placing the measured deionized water into a first beaker and a second beaker, carrying out temperature compensation to ensure that the conductivity of the deionized water in the first beaker and the second beaker is less than or equal to 2.0 mu S/cm, then accurately weighing 10g of dielectric filler, placing the dielectric filler into the first beaker, taking the second beaker as a blank control, and simultaneously placing the dielectric filler on an electromagnetic stirrer to stir for 30min to obtain a sample to be measured and a blank sample.

The method 2 comprises the following steps:

respectively measuring 50mL of deionized water, placing the deionized water into a first digestion tank and a second digestion tank, performing temperature compensation to ensure that the conductivities of the deionized water of the first digestion tank and the deionized water of the second digestion tank are respectively less than or equal to 2.0 muS/cm, then accurately weighing 5g of dielectric filler, adding the dielectric filler into the first digestion tank, using the second digestion tank as a blank control, placing the dielectric filler in a 95 ℃ constant-temperature drying box for 20 hours, taking out the dielectric filler, and cooling the dielectric filler to room temperature to obtain a sample to be measured and a blank sample.

Washing the electrode of the conductivity tester with a sample to be tested for 2-3 times, performing temperature compensation, and measuring the conductivity sigma 1 of the sample to be tested; the electrode was rinsed 2-3 times with a blank, temperature compensated, and the conductivity σ 2 of the blank was measured. The electrical conductivity (σ) of the dielectric filler is calculated according to the formula: σ 1- σ 2, μ S/cm.

Therefore, the number of free charged ions generated by the dielectric filler is effectively controlled by controlling the conductivity of the dielectric filler, and the ion migration resistance of the PCB based on the prepreg composition is further improved.

Of course, the lower the conductivity of the dielectric filler, the smaller the number of charged ions generating a free state, and therefore, it is further preferable that the conductivity of the dielectric filler is 410. mu.S/cm or less, or 400. mu.S/cm or less, or 350. mu.S/cm or less, or 300. mu.S/cm or less, or 200. mu.S/cm or less, or 100. mu.S/cm or less.

In the present invention, the dielectric filler having the conductivity satisfying the above requirements may be selected, or the dielectric filler may be surface-treated to satisfy the above requirements.

Specifically, the surface treatment method comprises the following steps: (1) cleaning the surface of the dielectric filler by adopting reagents such as acid, alkali and the like so as to reduce or consume substances which can generate free charged ions on the surface of the dielectric filler; (2) the surface of the dielectric filler is modified by adopting methods of surface modification, coating and the like so as to prevent the surface of the dielectric filler from contacting with the outside, thereby directly avoiding the surface of the dielectric filler from generating free charged ions.

Considering that the surface of the dielectric filler can generate charged ions, especially, the borosilicate glass type dielectric filler can generate free charged metal cations, so the application further preferably modifies the surface of the dielectric filler by surface modification, coating and the like, so that the surface of the dielectric filler has a modifier, and further preferably the modifier partially coats or completely coats the dielectric filler, so as to block the surface of the dielectric filler from generating free charged ions with the external base.

In some embodiments, the material of the modifier includes at least one of a surfactant, a titanate coupling agent, a silane coupling agent, a fluorosilane coupling agent, and an alkanolamine surface treating agent, and further preferably includes a high molecular compound having a chain structure capable of reacting with and linking with active groups such as hydroxyl groups on the surface of the dielectric filler, such as: higher fatty acid and its lipid, alcohol, amide, metal salt, etc. in the surfactant; monoalkoxy type, monoalkoxy pyrophosphate type, coordination type, chelate type, etc. in the phthalate ester coupling agent; vinyl type, amino type, epoxy type, isocyanate type, methacryloxy type, mercapto type, urea type, etc. among the silane coupling agents; tridecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltriethoxysilane, trifluoropropylmethyldimethoxysilane, etc., in the fluorosilane coupling agent; ethanolamine, diethanolamine, triethanolamine, triisopropanolamine, N' -bis (2-hydroxypropyl) aniline, 2-aminoethanol, 2-dibutylethanol, 2-diethylaminoethanol, polyvinyl alcohol, polydopamine, polyethyleneimine, polyimide, polyamic acid, and the like among the alkanolamines surface treating agents.

In order to increase the content of the modifier on the surface of the dielectric filler, so that the modifier can coat or completely wrap the dielectric filler, the surface of the dielectric filler can be pretreated to increase the content of active groups such as hydroxyl groups on the surface of the dielectric filler.

In other embodiments, the material of the modifier may also be inorganic material such as non-metal oxide, non-metal nitride, non-metal sulfide, etc., such as silicon dioxide, boron nitride, boron oxide, etc. At this time, the dielectric filler is partially or completely coated by the inorganic material such as silicon dioxide, boron nitride, boron oxide and the like, so that the composite dielectric filler with a core-shell structure taking the dielectric filler as a core and the inorganic material such as silicon dioxide and the like as a shell is formed. The shell layer preferably accounts for 0.1-30% of the composite dielectric filler by mass, more preferably 1-20% of the composite dielectric filler by mass, and even more preferably 5-10% of the composite dielectric filler by mass.

The absolute value of the difference value of the Df of the composite dielectric material and the Df of the dielectric material is less than or equal to 0.01, so that the conductivity of the dielectric filler can be improved, and the dielectric property of the dielectric filler can be ensured.

Furthermore, compared with organic materials such as surfactants, titanate coupling agents, silane coupling agents, alcohol amine surface treatment agents and the like, the inorganic materials do not generate ion precipitation, and the inorganic materials are coated on the surface of the dielectric filler in a reaction mode, a high-temperature sintering mode and the like, so that a compact coating layer can be formed. Therefore, the composite dielectric filler obtained by using the inorganic material as a modifier has lower conductivity.

In the prepreg composition of the present invention, the mass ratio of the resin to the dielectric filler is 100:60 to 100: 150.

Specifically, the dielectric filler comprises at least one of titanium dioxide, polytetrafluoroethylene, barium titanate, strontium titanate, amorphous silica, spherical silica, corundum, wollastonite, solid glass microspheres, hollow glass microspheres, kaolin, mullite, hollow silica microspheres, hollow titanium dioxide microspheres, synthetic glass, quartz, boron oxide, boron nitride, aluminum carbide, beryllium oxide, aluminum hydroxide, magnesium oxide, mica, talc and magnesium hydroxide, and is selected and compounded according to different requirements on dielectric properties.

Specifically, the resin includes at least one of polybutadiene, polyisoprene, modified polybutadiene, a copolymer of polybutadiene and styrene, a block copolymer or a graft copolymer which can undergo a copolymerization crosslinking reaction, a thermosetting liquid crystal resin, a phenol resin, a cyanate ester resin, a polyphenylene ether resin, a maleimide resin, a modified polyphenylene ether resin, a polyimide resin, a phenoxy resin, a polytetrafluoroethylene resin, a benzoxazine resin, a melamine-formaldehyde resin, a furan resin, a silicone resin, a urea resin, and an epoxy resin.

Further, the prepreg composition further comprises at least one of a curing agent, a coupling agent and an auxiliary crosslinking agent. The resin comprises 100 parts by weight of resin, 1 to 10 parts by weight of curing agent, less than or equal to 5 parts by weight of coupling agent and less than or equal to 15 parts by weight of auxiliary crosslinking agent.

Specifically, the curing agent comprises at least one of 2, 5-dimethyl-2, 5-di (benzyl peroxide) hexane, di-tert-butyl peroxide, 2, 5-dimethyl-2, 5-bis (tert-butylperoxy) hexane, 2, 5-dimethyl-2, 5-di-tert-butylperoxy-3-hexyne and dicumyl peroxide; the coupling agent comprises at least one of silane coupling agent, titanate coupling agent and aluminate coupling agent; the auxiliary crosslinking agent comprises at least one of triallyl isocyanurate, triallyl cyanurate, diallyl terephthalate, divinylbenzene and multifunctional acrylate.

In a second aspect of the present invention, a prepreg is further provided, which includes a reinforcing material and the prepreg composition as described above attached to the reinforcing material.

Wherein, the reinforcing material is preferably glass fiber cloth.

Specifically, the resin, the dielectric filler and the curing agent are mixed according to the weight ratio, diluted to proper viscosity by a solvent, so that the dielectric filler is uniformly dispersed in the resin to prepare a glue solution, the glue solution is impregnated by a reinforcing material, and then the solvent is removed to prepare the prepreg.

In a third aspect of the present invention, a circuit substrate is further provided, which includes a dielectric layer and a conductive layer disposed on at least one surface of the dielectric layer, wherein the dielectric layer is formed by curing the prepreg.

Specifically, the number of the prepregs may be one or more, and when a plurality of prepregs are stacked, the prepregs are cured to obtain the dielectric layer.

Wherein the curing temperature is 100-300 ℃, and the curing pressure is 10kg/cm²～80kg/cm²During the curing process, the third resin in the mixed resin and the second resin modified on the surface of the filler react with the first resin to form chemical bonds and are polymerized together.

Specifically, the metal foil is preferably a copper foil, so that a copper-clad plate is obtained.

The circuit substrate has excellent dielectric constant and dielectric loss, and the range is adjustable.

In a fourth aspect of the present invention, a printed circuit board is further provided, which includes the above-mentioned circuit substrate, and is mainly manufactured by the processes of drilling a board, hole trimming, microetching, pre-dipping, activating, accelerating, chemical copper and copper thickening, etc. on the circuit substrate.

In the printed circuit board, because the dielectric filler in the dielectric layer of the circuit substrate has low conductivity, when the printed circuit board is used, the quantity of the charged ions in a free state is small, and therefore, the ion migration resistance of the PCB is effectively improved.

Hereinafter, the prepreg composition, prepreg, circuit board and printed circuit board will be further described with reference to the following specific examples.

TABLE 1

The method for coating the silicon dioxide comprises the following steps:

taking 90g of D₅₀Putting 25 mu m hollow glass microspheres, 57mL deionized water and 262mL ethanol in a flask, stirring for 30min under heating in a water bath at 60 ℃, adopting a cocurrent feeding mode, simultaneously and slowly dropwise adding 131mL ethanol solution containing 9.36g of Tetraethoxysilane (TEOS) and 18.4g of ammonia water into the flask, controlling the concentration of the slurry to be 200g/L, and using SiO to prepare the mixed solution₂Calculated, the adding amount of TEOS is 3% of the mass of the hollow glass microsphere, and the concentration of the catalyst ammonia water is 4% of the mass of the hollow glass microsphere. And after the dropwise addition is finished for 90min, curing for 2h, washing with deionized water until the conductivity of the washing liquid is lower than 100, and drying in an oven at 100 ℃ for more than 12h to obtain the third dielectric filler.

The method of boron oxide coating comprises the following steps:

weighing 10 parts by weight of D₅₀Putting 25 mu m hollow glass microspheres and 1 part by weight of boron oxide micro powder into a clean container, adding a proper amount of ethanol and distilled water according to a volume ratio of 3: 1, carrying out ultrasonic oscillation for 1-5 hours, and then mechanically stirring for more than 4 hours. Stirring the mixtureAnd after the mixture is completely mixed, placing the mixture in a drying oven at 105 ℃ for 12-24 hours, completely drying, and calcining in a muffle furnace at 700 ℃ for 12 hours to obtain the fourth dielectric filler.

The surface modification method of the surface modifier comprises the following steps:

firstly, D is₅₀Putting the hollow glass microspheres with the diameter of 25 mu m into deionized water, fully stirring, standing for 2h, and filtering and drying the hollow glass microspheres floating on the upper layer. Then mixing 1 part of hollow glass microsphere and 30 parts of 0.3mol/L sodium hydroxide solution in a three-neck flask according to the mass ratio, refluxing and stirring at 80 ℃ for 1.5h, then washing the hollow glass microsphere with deionized water until the pH value of a washing solution is 7, performing suction filtration and drying, and drying in a constant-temperature drying oven at 100 ℃ to obtain the hydroxylated hollow glass microsphere.

Mixing 10 parts by mass of hydroxylated hollow glass microspheres in 30 parts by mass of 40-80% ethanol aqueous solution, adding 1 part by mass of surface modifier under the condition of stirring at 80 ℃, continuously heating and stirring for 2 hours, washing off the surface modifier remained on the surfaces of the hollow glass microspheres by using ethanol, performing suction filtration, and drying in an oven at 100 ℃ to obtain a fifth dielectric filler, a sixth dielectric filler and a seventh dielectric filler.

Example 1:

mixing 72 parts by weight of first resin, 28 parts by weight of second resin, 40 parts by weight of first dielectric filler, 20 parts by weight of third dielectric filler, 1.8 parts by weight of coupling agent, 3 parts by weight of curing agent and 10 parts by weight of auxiliary crosslinking agent, adjusting the mixture to proper viscosity by using a xylene solvent, stirring and uniformly mixing to uniformly disperse the dielectric filler in the resin to obtain a glue solution.

The glue solution is impregnated by 1080 glass fiber cloth, and the gram weight is controlled to be 189 +/-3 g/m²And then drying to remove the solvent to obtain the tack-free prepreg.

Overlapping six prepregs, covering TZA copper foils with the thickness of 1oz on two sides, and carrying out temperature programming curing in a high-temperature vacuum press under the curing pressure of 60kg/cm²Curing at 170 ℃ for 2h, then heating to 270 ℃ and curing for 1h to obtain the circuit substrate.

The PCB processing is carried out aiming at the circuit substrate, and the process flow comprises the following steps: drilling plate → whole hole → micro-etching → presoaking → activation → acceleration → chemical copper → copper thickening. The dielectric property test and the CAF test are carried out on the alloy, and the results are shown in a table 2.

Wherein, the dielectric property test uses vector net mark instrument of Rosenberg.

The CAF test method is as follows:

the PCB is placed in an environment with the temperature of 23 +/-2 ℃ and the relative humidity of 50 +/-5% and is kept constant for 30min, the normal insulation resistance of the PCB is measured, and the test voltage is 50 +/-1 VDC. The environment was raised to 85 + -2 deg.C and 85 + -3% relative humidity and held constant for 96h, during which no bias voltage was applied. And testing the insulation resistance at 96h during the period without bias voltage, wherein the test voltage is 50 +/-1V. After the constant 96h was completed, a bias voltage of 50 ± 1VDC was applied, and insulation resistance was measured every 1h until 500h (bias period) while the polarity of the measurement voltage and the polarity of the bias voltage were kept consistent.

Examples 2 to 8

The preparation process was the same as in example 1, and the composition was changed as shown in Table 2.

Comparative examples 1 to 3

The preparation process was the same as in example 1, and the composition was changed as shown in Table 2.

TABLE 2

As can be seen from Table 2, the ion migration resistance of the PCB using the dielectric filler having the conductivity of less than 450. mu.S/cm is remarkably improved. In comparative example 3, the flow adhesive is too large to be pressed into a plate for testing.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.