TWM636357U - Prepreg and conductive substrate using the same - Google Patents

Abstract

The invention discloses a prepreg and a conductive substrate using the same. The prepreg includes a reinforcement structure and a resin adhesive layer attached to the reinforcement structure. The material of the resin adhesive layer comprises 15 to 25 parts by weight of liquid epoxy resin, 20 to 30 parts by weight of novolac epoxy resin, 5 to 20 parts by weight of hardener, 15 to 20 parts by weight of flame retardant and 25 to 20 parts by weight of 35 parts by weight of filler, wherein the molecular weight of the liquid epoxy resin is 300 to 1000. Therefore, the prepreg and conductive substrate of the present invention can make the circuit board achieve the expected electrical and mechanical characteristics, heat resistance and reliability.

Description

Prepreg and its conductive substrate

The invention relates to the technical field of circuit boards, in particular to a prepreg and a conductive substrate using it.

Circuit board is an indispensable main component for most electronic products to achieve circuit interconnection. Its basic materials include copper clad substrate (Copper Clad Laminate, CCL) and prepreg (Prepreg). The copper foil substrate is used to make the inner core board of the multilayer circuit board, and the main function of the prepreg is to bond a single or multiple inner core boards with the copper foil, and the resin composition contained in the prepreg Fills circuit gaps and holes in inner core boards.

With the rapid development of automotive electronics, power supply, aviation and other industries and the wide application of printed circuit boards in the electronic field, equipment has higher and higher functional requirements for PCBs. In addition to providing the necessary electrical connections and mechanical In addition to the necessary functions of support, special functions such as high power, high heat dissipation, and high reliability are required. Under this background, thick copper multilayer printed circuit boards have gradually become a product with broad market prospects, and the demand in the market is increasing day by day. However, the filling effect of the existing epoxy resin composition prepreg is not good, and it is prone to insufficient filling, resulting in voids or air bubbles in the multilayer circuit board, which has a negative impact on reliability.

Aiming at the deficiencies of the prior art, the invention provides a prepreg and a conductive substrate using it to solve the quality problem of cavities or air bubbles in the multilayer circuit board.

In order to solve the above technical problems, one of the technical solutions adopted in this creation is to provide a prepreg, which includes a reinforcement structure and a resin adhesive layer attached to the reinforcement structure; wherein, the material of the resin adhesive layer includes: ( A) 15 to 25 parts by weight of liquid epoxy resin, the molecular weight of said liquid epoxy resin is 300 to 1000; (B) 20 to 30 parts by weight of novolac epoxy resin; (C) 5 to 20 parts by weight of a hardener; (D) 15 to 20 parts by weight of a flame retardant; and (E) 25 to 35 parts by weight of a filler.

In one embodiment of the invention, the reinforcing structure is formed of glass fiber paper, glass fiber cloth or a combination thereof.

In one embodiment of the present invention, the reinforcing structure is glass fiber paper of 20 g/m ² to 50 g/m ² .

In one embodiment of the present invention, the resin content of the prepreg is 80% to 92%.

In one embodiment of the invention, the flame retardant is a phosphorus-containing phenolic resin.

In one embodiment of the present creation, the hydroxyl equivalent of the phosphorus-containing phenolic resin is 300 g/OH to 500 g/OH, the phosphorus content of the phosphorus-containing phenolic resin is 8% to 10%, and the phosphorus-containing phenolic resin Phosphorus phenolic resins have a solids content of 54% to 62%.

In order to solve the above technical problems, another technical solution adopted in the present invention is to provide a conductive substrate, which includes an inner core board and two conductive layers. The inner core board has an opposite first surface and a second surface, and the two conductive layers are respectively arranged on the first surface and the second surface through an adhesive layer, and the adhesive layer Layers are formed from the prepregs described above.

In another embodiment of the present invention, each of the two conductive layers is a copper foil layer.

In another embodiment of the present invention, each of the two conductive layers is a patterned circuit layer.

The beneficial effect of this creation is that this creation adopts the above formula composition, including 15 to 25 parts by weight of liquid epoxy resin, 20 to 30 parts by weight of novolac epoxy resin, 5 to 20 parts by weight of hardener, 15 to 20 parts by weight The flame retardant of parts by weight and the filler of 25 to 35 parts by weight improve the fluidity of the epoxy resin composition and the ability to fill the pores, so the conductive substrate can completely fill the pores, such as the gaps between thick copper lines and Holes or depressions with a high aspect ratio, thus solving the quality problem of voids or air bubbles in multilayer circuit boards.

Furthermore, when the molecular weight of the liquid epoxy resin is between 300 and 1000, the formed prepreg has appropriate viscosity and sufficient flexibility and fluidity, and has good handling during lamination. and adaptability, for example, the prepreg has good gap filling ability and is not easy to break.

In addition, the prepreg and conductive substrate of this creation can make the circuit board achieve the expected electrical and mechanical characteristics, heat resistance and reliability, thereby meeting the requirements of high-performance circuit boards, suitable for automotive electronics, power supply and other fields, and has a wide range of applications prospect.

In order to further understand the characteristics and technical content of this creation, please refer to the following detailed description and drawings about this creation. However, the provided drawings are only for reference and explanation, and are not used to limit this creation.

The following is a description of the implementation of the "prepreg and conductive substrate" disclosed in this creation through specific specific examples. Those skilled in the art can understand the advantages and effects of this creation from the content disclosed in this specification. This creation can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed based on different viewpoints and applications without departing from the idea of this creation. In addition, the drawings of this creation are only for simple illustration, not according to the actual size of the depiction, prior statement. The following embodiments will further describe the relevant technical content of this creation in detail, but the disclosed content is not intended to limit the protection scope of this creation. In addition, the term "or" used herein may include any one or a combination of more of the associated listed items depending on the actual situation.

Unless otherwise defined, terms used herein have the same meaning as commonly understood by those skilled in the art. The materials involved in each embodiment are commercially available or prepared according to the prior art unless otherwise specified. The operations or instruments involved in each embodiment are conventional operations or instruments in the art unless otherwise specified.

It should be understood that although various steps in the method flow diagrams are described herein in a particular order, this does not require or imply that the steps must be performed in this particular order, or that all steps must be performed, to achieve the desired results . Optionally, multiple steps may be combined into one step for execution, or one step may be decomposed into multiple steps for execution.

[Epoxy resin composition]

The present creative embodiment provides an epoxy resin composition, comprising the following components by weight: (A) 15 to 25 parts by weight of liquid epoxy resin; (B) 20 to 30 parts by weight of novolac epoxy resin; ( C) 5 to 20 parts by weight of hardener; (D) 15 to 20 parts by weight of flame retardant; and (E) 25 to 35 parts by weight of filler.

It is worth mentioning that the epoxy resin composition of this invention is composed of the above formula, which can make the prepreg have high fluidity and good filling performance (porosity filling), and can make the gap between thick copper lines, high aspect ratio The holes or depressions are completely filled and flat, which solves the quality problem of voids or air bubbles in multilayer circuit boards. In addition, the epoxy resin composition of this invention can make the circuit board achieve the expected electrical and mechanical characteristics, heat resistance and reliability, thereby meeting the requirements of high-performance circuit boards, suitable for automotive electronics, power supply and other fields, and has broad applications. Application prospect.

It should be noted that although the application of the circuit board is used as an example to describe the characteristics of the epoxy resin composition of this creation, the epoxy resin composition of this creation can also have other applications, such as electronic components packaging material.

[Liquid epoxy resin]

In this creation, the liquid epoxy resin can improve the compatibility between the various components, and can improve the fluidity of the cured system (in the form of a film). The molecular weight of the liquid epoxy resin may range from 300 to 1000, and preferably from 300 to 500. When the molecular weight of the liquid epoxy resin is between 300 and 1000, the formed prepreg has appropriate viscosity and sufficient flexibility and fluidity, and has good operability and adaptability when pressing, For example, prepreg has good gap filling ability and is not easy to break.

The choice of liquid epoxy resin mainly considers the fluidity and filling properties of the prepreg and the comprehensive performance of the circuit board, including electrical insulation performance, breakdown voltage resistance, thermal conductivity and heat resistance, as well as the operability and Adaptability: specific examples of liquid epoxy resins include liquid bisphenol A epoxy resins and liquid bisphenol F epoxy resins, which can be used alone or in combination. However, the present invention is not limited to the above-mentioned examples. In actual application, the addition amount of liquid epoxy resin in the epoxy resin composition can be 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight parts, 23 parts by weight, 24 parts by weight, or 25 parts by weight.

[Novolak type epoxy resin]

In this creation, the novolac epoxy resin as the main resin can improve the heat resistance of the curing system, and because it contains more epoxy groups, it can increase the crosslinking density of the curing system, so that the epoxy resin composition has good properties after curing. physical and mechanical properties. The choice of novolac epoxy resin is also to consider the fluidity and filling properties of the prepreg and the comprehensive performance of the circuit board, as well as the operability and adaptability to the lamination process; specific examples of novolac epoxy resin include o-methylphenol-formaldehyde Epoxy resin, bisphenol A novolac epoxy resin, novolak epoxy resin and phosphorous novolac epoxy resin can be used alone or in combination. However, the present invention is not limited to the above-mentioned examples. During actual application, the addition amount of novolac epoxy resin in the epoxy resin composition can be 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight. parts by weight, 28 parts by weight, 29 parts by weight, or 30 parts by weight.

[Other epoxy resins]

According to actual needs, within the scope of not damaging the effect of this creation, the epoxy resin composition of this creation can also contain other epoxy resins, such as trisphenol methane type epoxy resin, glycidylamine type epoxy resin, Aminophenol type epoxy resin, naphthalene type epoxy resin, isocyanate modified epoxy resin, etc.

[hardener]

In this creation, the hardener can be polymerized with the epoxy group of the epoxy resin to form a cured product with a three-dimensional network structure. The hardener plays a decisive role in the manufacturability of the epoxy resin composition and the final performance of the cured product; Specific examples of hardening agents include dicyandiamide, phenolic resin and diaminobenzene, which can be used alone or in combination. However, the present invention is not limited to the above-mentioned examples. In actual application, the amount of hardener added in the epoxy resin composition can be 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, or 20 parts by weight.

It should be noted that the amount of hardener added to the epoxy resin composition is preferably to maintain an appropriate ratio between the total number of epoxy groups of the epoxy resin and the total number of reactive functional groups of the hardener; When the amount added to the epoxy resin composition is not in the range of 5 to 20 parts by weight, the final performance of the cured product of the epoxy resin composition may be deteriorated.

[flame retardant]

In this creation, the purpose of adding a flame retardant is to improve the flame retardancy of the epoxy resin composition and its cured product, so that the circuit board product can meet the requirements of UL94 V-0 level. In practical application, phosphorus-containing phenolic resin can be used as the flame retardant; preferably, the phosphorus-containing phenolic resin has the following characteristics: the hydroxyl equivalent is 300 g/OH to 500 g/OH; the phosphorus content is 8% to 10%; and solid The content is 54% to 62%. Accordingly, the epoxy resin composition can not only achieve the expected flame retardant effect, but also improve the insulation, heat resistance and dimensional stability of the cured product. However, the above descriptions are only feasible implementation manners, and are not intended to limit the present invention.

[filler]

In this creation, the addition of fillers can not only achieve the expected properties of the epoxy resin composition, such as high thermal conductivity, low dielectric or high dielectric properties, but also achieve other beneficial effects, including: improving the insulation of the cured product Sex, heat resistance, flame retardancy, dimensional stability, etc., reduce cost, and improve the peel strength between copper foil and substrate. However, the above description of the role of fillers is not intended to limit the present invention. Specific examples of fillers include aluminum silicate, aluminum oxide, aluminum hydroxide, silicon dioxide, kaolin, talc and titanium dioxide, which can be used alone or in combination. However, the present invention is not limited to the above-mentioned examples.

In actual application, the amount of filler added in the epoxy resin composition can be 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight parts by weight, 34 parts by weight, or 35 parts by weight. In addition, the filler can be dispersed in the epoxy resin composition in the form of particles or flakes, and the median particle size (D50) of the filler can be 0.8 micron to 3.0 micron. Therefore, the effect of the filler can be better exerted and the above-mentioned beneficial effects can be realized.

According to actual needs, such as improving the dispersibility of the filler in the epoxy resin and the compatibility with the epoxy resin, a surface treatment agent (such as epoxy silane coupling agent) can be used to modify the filler. After treatment, the surface of the filler may have modifying functional groups (such as epoxy groups), that is, the surface of the filler is covered by a sufficient amount of modifying functional groups.

[prepreg]

1 to 3, the epoxy resin composition of the present invention can be used to make a prepreg 1A; the prepreg 1A includes a reinforcement structure 11 and a resin adhesive layer 12 attached to the reinforcement structure 11, wherein the resin adhesive layer 12 is formed of an epoxy resin composition, and the reinforcing structure 11 can be formed by glass fiber paper, glass fiber cloth or a combination thereof, preferably glass fiber paper, but the invention is not limited thereto. It should be noted that the filling ability of glass fiber paper is better than that of glass fiber cloth. The reason is that the fiber distribution in glass fiber paper is non-directional (the fibers are randomly distributed in disorder), and the fiber distribution in glass fiber cloth is directional. (The fibers are distributed along the length of the warp and weft yarns). Therefore, the resin content of the prepreg 1A using glass fiber paper will be higher than that of the prepreg 1A using glass fiber cloth.

Furthermore, the resin content of the prepreg 1A made of the epoxy resin composition of the present invention and the reinforced structure 11 based on glass fiber paper can reach 80% to 92%, which is conducive to the complete filling of the pores, such as thick Voids between copper traces and high aspect ratio holes or depressions.

Please refer to Fig. 4, the steps of using the epoxy resin composition of the present invention to make a prepreg 1A include at least: step S1, immersing the reinforcing structure 11 in the epoxy resin composition for 1 to 5 minutes; and step S2, obtaining The composite material is baked at a temperature of 160°C to 200°C for 2 to 6 minutes. However, the above descriptions are only feasible implementation manners, and are not intended to limit the present invention. In some embodiments, the epoxy resin composition can also be impregnated and adhered to the reinforcing structure 11 by coating.

[conductive substrate]

Please refer to Fig. 5 to Fig. 7 and shown in Fig. 3, the prepreg 1A based on the epoxy resin composition of the present invention can be used to make the conductive substrate Z, but the present invention is not limited thereto; the conductive substrate Z includes a Layer core board 2 and two conductive layers 3, the inner layer core board 2 has a first surface 21 (such as the upper surface) and a second surface 22 (such as the lower surface) opposite, and the two conductive layers 3 are respectively passed through a bonding layer 1 is disposed on the first surface 21 and the second surface 22 of the inner core board 2, wherein the bonding layer 1 may be formed by one or more prepregs 1A. Further, the conductive substrate Z can be a copper clad substrate (or copper clad laminate, CCL) formed by thermocompression, wherein the two conductive layers 3 are each a copper foil layer. It is worth mentioning that the prepreg 1A can fill the gaps, depressions or other similar structures existing on the first surface 21 and the second surface 22 of the inner core board 2, so that the gap between the inner core board 2 and the two conductive layers 3 There are no voids or air bubbles in between.

In an embodiment not shown, in the conductive substrate Z, only one conductive layer 3 may be disposed on the first surface 21 or the second surface 22 of the inner core board.

Please refer to FIG. 7 , the conductive substrate Z can also be a circuit substrate formed of the copper foil substrate shown in FIG. 6 . In the example shown in FIG. 6, two conductive layers 3 (such as two copper foil layers) are respectively patterned to form a patterned circuit layer 3'; the patterning method includes steps such as exposure, development, etching, etc., but this Creation is not limited to this.

In an unillustrated embodiment, only one patterned circuit layer 3' may be disposed on the first surface 21 or the second surface 22 of the inner core board 2 in the conductive substrate Z.

[Advantageous Effects of Embodiment]

The beneficial effect of this creation is that this creation adopts the above formula composition, including 15 to 25 parts by weight of liquid epoxy resin, 20 to 30 parts by weight of novolac epoxy resin, 5 to 20 parts by weight of hardener, 15 to 20 parts by weight The flame retardant of parts by weight and the filler of 25 to 35 parts by weight improve the fluidity of the epoxy resin composition and the ability to fill the pores, so the conductive substrate can completely fill the pores, such as the gaps between thick copper lines and Holes or depressions with a high aspect ratio, thus solving the quality problem of voids or air bubbles in multilayer circuit boards.

Furthermore, when the molecular weight of the liquid epoxy resin is between 300 and 1000, the formed prepreg has appropriate viscosity and sufficient flexibility and fluidity, and has good handling during lamination. and adaptability, for example, the prepreg has good gap filling ability and is not easy to break.

In addition, the prepreg and conductive substrate of this creation can make the circuit board achieve the expected electrical and mechanical characteristics, heat resistance and reliability, thereby meeting the requirements of high-performance circuit boards, suitable for automotive electronics, power supply and other fields, and has a wide range of applications prospect.

The content disclosed above is only the preferred feasible embodiment of this creation, and does not limit the scope of patent application for this creation. Therefore, all equivalent technical changes made by using the instructions and drawings of this creation are included in the application of this creation. within the scope of the patent.

Z: Conductive substrate 1A: Prepreg 11: Enhanced structure 12: Resin adhesive layer 1: the next layer 2: Inner core board 21: First Surface 22: Second Surface 3: Conductive layer 3': patterned circuit layer S1, S2: the step of making prepreg

Figure 1 and Figure 2 are schematic diagrams of the steps of making a prepreg using the epoxy resin composition of the present invention.

Fig. 3 is a partially enlarged schematic view of a prepreg made using the epoxy resin composition of the present invention.

Fig. 4 is a flow chart of the steps of making a prepreg using the epoxy resin composition of the present invention.

FIG. 5 is a schematic structural view of a conductive substrate based on the prepreg of the present invention.

FIG. 6 is another structural schematic diagram of the conductive substrate based on the prepreg of the present invention.

FIG. 7 is another structural schematic diagram of the conductive substrate based on the prepreg of the present invention.

1A: Prepreg

11: Enhanced structure

12: Resin adhesive layer

Claims (9)

A prepreg, which includes a reinforcement structure and a resin adhesive layer attached to the reinforcement structure; Wherein, the material of the resin glue layer includes: (A) 15 to 25 parts by weight of liquid epoxy resin, the molecular weight of the liquid epoxy resin is 300 to 1000; (B) 20 to 30 parts by weight of phenolic ring (C) 5 to 20 parts by weight of hardener; (D) 15 to 20 parts by weight of flame retardant; and (E) 25 to 35 parts by weight of filler. The prepreg according to claim 1, wherein the reinforcing structure is formed of glass fiber paper, glass fiber cloth or a combination thereof. The prepreg according to claim 2, wherein the reinforcing structure is glass fiber paper of 20 g/m ² to 50 g/m ² . The prepreg according to claim 3, wherein the resin content of the prepreg is 80% to 92%. The prepreg according to claim 1, wherein the flame retardant is a phosphorus-containing phenolic resin. The prepreg as described in claim 5, wherein the hydroxyl equivalent of the phosphorus-containing phenolic resin is 300 g/OH to 500 g/OH, the phosphorus content of the phosphorus-containing phenolic resin is 8% to 10%, and the The solid content of phosphorus-containing phenolic resin is 54% to 62%. A conductive substrate comprising: an inner core board having an opposite first surface and a second surface; and Two conductive layers are respectively provided on the first surface and the second surface through an adhesive layer, wherein the adhesive layer is formed of the prepreg as described in Claim 1. The conductive substrate as claimed in claim 7, wherein each of the two conductive layers is a copper foil layer. The conductive substrate as claimed in claim 7, wherein each of the two conductive layers is a patterned circuit layer.

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