TWI484014B - Printed circuit board subatrate and method for manufacturing the same - Google Patents

Description

Circuit board substrate and manufacturing method thereof

The present invention relates to the field of circuit board technology, and in particular, to a circuit board substrate which is applied to a circuit board and has an electromagnetic shielding function and a manufacturing method thereof.

With the advancement of science and technology, printed circuit boards have been widely used in the field of electronics. For application of the circuit board, please refer to the literature Takahashi, A.Ooki, N.Nagai, A.Akahoshi, H.Mukoh, A.Wajima,M.Res.Lab,High density multilayer printed circuit board for HITAC M-880,IEEE Trans .on Components, Packaging, and Manufacturing Technology, 1992, 14(4): 418-425.

As the number of circuit board product layers increases, the circuit board products often generate electromagnetic interference when they are actually working, which affects the signal transmission of the circuit board. Thus, an electromagnetic mask layer needs to be provided in the circuit board product. At present, the electromagnetic shielding layer is usually made of a stainless steel sheet having a small thickness, and the stainless steel sheet is disposed between two copper foil layers adjacent to the circuit board product, thereby functioning as an electromagnetic mask. However, the weight of the stainless steel sheet is large, thereby increasing the weight of the board product. Moreover, the stainless steel sheet has poor flexibility, and the electromagnetic shielding layer made of stainless steel sheet affects the flexural performance of the flexible circuit board. Due to the higher price of stainless steel sheets, the production cost of the board is increased.

In view of the above, it is necessary to provide a circuit board substrate that can be applied to a circuit board to function as an electromagnetic mask and a method of manufacturing the same.

A circuit board substrate comprising a first copper foil layer, a first insulating layer, an epoxy resin composite material layer, a second insulating layer and a second copper foil layer stacked in sequence. The epoxy resin composite layer is composed of an epoxy resin composite material. The epoxy resin composite material comprises a carboxyl group-modified epoxy resin, a carbon nanotube and an inorganic dispersion material, and the weight percentage of the carbon nanotube in the epoxy resin composite material is 4.6. % to 16%.

A method for manufacturing a circuit board substrate, comprising the steps of: preparing an epoxy resin composite material comprising an epoxy resin modified with a terminal carboxyl group polymer, a carbon nanotube, and an inorganic dispersion material, wherein the nanometer The carbon tube accounts for 4.6% to 16% by weight of the epoxy resin composite material; the epoxy resin composite material is used to form an epoxy resin composite material layer, and the epoxy resin composite material layer is semi-cured; Providing a first copper clad plate including a first copper foil layer and a first insulating layer; disposing an epoxy resin composite material layer on a surface of the first insulating layer of the first copper clad laminate; performing the epoxy resin composite material layer Softening treatment; providing a second copper clad plate comprising a second copper foil layer and a second insulating layer; placing the second copper clad plate on the surface of the epoxy resin composite layer, and making the second insulating layer and the epoxy resin composite layer Contacting; and pressing the first copper clad laminate, the epoxy resin composite material layer and the second copper clad laminate by means of roller pressing, so that the epoxy resin composite material layer is cured and bonded to the first copper clad laminate and the first Two copper clad laminates to obtain a circuit board substrate.

Compared with the prior art, the circuit board substrate provided by the technical solution has a uniformly dispersed carbon nanotube in the epoxy resin composite layer because an epoxy resin composite layer is disposed between adjacent copper foil layers. And have an electromagnetic masking effect when the circuit board When the two copper foil layers of the substrate are formed to form a conductive line, the epoxy resin composite material layer can function as an electromagnetic mask. Moreover, the epoxy resin composite layer has good flexibility, and the flexural performance of the flexible circuit board can be increased compared with the stainless steel sheet, and the production cost of the circuit board can be reduced. The method for manufacturing the circuit board substrate provided by the technical solution can realize the curing of the epoxy resin composite material layer by pressing the roller, so that the epoxy resin composite material layer does not need to be matured, thereby saving the circuit board. The cost of the substrate improves the production efficiency of the circuit board substrate.

100‧‧‧Circuit board

101‧‧‧First CCL

102‧‧‧Second CCL

110‧‧‧First copper foil layer

120‧‧‧First insulation

130‧‧‧Epoxy composite layer

140‧‧‧Second insulation

150‧‧‧Second copper foil layer

20‧‧‧ release substrate layer

210‧‧‧First release surface

31‧‧‧First wheel

32‧‧‧Second wheel

1 is a cross-sectional view of a circuit board substrate provided by an embodiment of the present technical solution.

2 is a cross-sectional view of a release substrate layer provided by an embodiment of the present technical solution.

3 is a cross-sectional view showing the epoxy resin composite layer formed on the surface of the release substrate layer according to an embodiment of the present technical solution.

4 is a cross-sectional view of a first copper clad plate provided by an embodiment of the present technical solution.

FIG. 5 is a cross-sectional view showing an epoxy resin composite layer provided on a first insulating layer according to an embodiment of the present technical solution.

6 is a cross-sectional view of a second copper clad plate provided by an embodiment of the present technical solution.

FIG. 7 is a schematic view showing the first copper clad laminate, the epoxy resin composite material layer and the second copper clad laminate when the embodiment of the present technical solution is rolled.

The circuit board substrate with electromagnetic shielding function provided by the technical solution and the manufacturing method thereof will be further described in detail below with reference to the embodiments.

Referring to FIG. 1 , the technical solution provides a circuit board substrate 100 including a stack in sequence. The first copper foil layer 110, the first insulating layer 120, the epoxy resin composite material layer 130, the second insulating layer 140, and the second copper foil layer 150 are stacked.

In this embodiment, the materials of the first insulating layer 120 and the second insulating layer 140 are all polyimide. The circuit board substrate 100 includes a first copper clad plate 101 including a first copper foil layer 110 and a first insulating layer 120, an epoxy resin composite material layer 130, and a second cover including a second copper foil layer 150 and a second insulating layer 140. The copper plate 102 is composed. The material of the first copper foil layer 110 and the second copper foil layer 150 may be replaced by other metal materials capable of making conductive lines, such as silver or aluminum. The material of the first insulating layer 120 and the second insulating layer 140 may also be other materials used as an insulating layer in the circuit board, such as polyester.

The epoxy resin composite layer 130 is used to function as an electromagnetic mask and bond the first insulating layer 120 and the second insulating layer 140. The thickness of the epoxy resin composite layer 130 can be set according to the actual electromagnetic interference of the mask. The epoxy composite layer 130 has a thickness of between about 8 microns and 12 microns. The epoxy resin composite layer 130 is made of an epoxy resin composite material including a carboxyl group-modified epoxy resin, a carbon nanotube, an inorganic dispersion material, a hardener, a catalyst, and a solvent. And defoamer.

The epoxy resin modified by the terminal carboxyl group is a product obtained by copolymerization of an epoxy resin and a terminal carboxyl group polymer, that is, an epoxy group at the terminal of the epoxy resin reacts with a carboxyl group at the terminal end of the terminal carboxyl polymer. An ester group is formed to obtain a polymer having repeating units including alternating epoxy repeating units and terminal carboxyl groups. Wherein, the epoxy resin may be a bisphenol A type epoxy resin, and the terminal carboxyl group polymer may be a liquid polybutadiene acrylonitrile (CTBN). In the present embodiment, the epoxy resin used before the unmodified epoxy resin has an epoxy equivalent of about 500, and the epoxy resin of the modified carboxyl group has an epoxy equivalent of about 950 to 1100, preferably about 1029. End carboxyl polymer modified epoxy resin The weight percentage in the epoxy resin composite is from about 50% to about 60%, preferably from about 55% to about 57%.

As a conductive material, the carbon nanotubes are uniformly dispersed in the epoxy resin modified with the terminal carboxyl group to function as an electromagnetic mask. The carbon nanotubes account for 4.6% to 16% by weight of the composite. The content of the carbon nanotubes in the composite material can be determined according to the actual needs of the electrical conductivity of the composite material. The more the content of the carbon nanotubes in the epoxy resin composite material, the smaller the electric resistance of the epoxy resin composite material, and the smaller the content of the carbon nanotubes in the composite material, the greater the electrical resistance of the epoxy resin composite material.

The inorganic dispersion material is used to disperse the carbon nanotubes so that the carbon nanotubes can be uniformly distributed in the epoxy resin composite. The inorganic dispersion material is nano clay or nano mica powder. The nano clay is a 2:1 page citrate, which may specifically be montmorillonite (Molecular formula M _x (Al _4-x Mg _x )Si ₈ O ₂₀ (OH) ₄ ), lithium montmorillonite Stone (Hectorite, molecular formula M _x (Mg _6-x Li _x )Si ₈ O ₂₀ (OH) ₄ ) or saponite (Saponite, molecular formula M _x Mg ₆ (Si _8-X Al _x )O ₂₀ (OH) ₄ ) Wait. Wherein, the weight ratio of the carbon nanotubes to the inorganic dispersion material is 3 to 4 to 1. The inorganic dispersion material is preferably a nano clay.

The hardener is used to harden the composite during curing. In the present embodiment, the hardener used is a polyether amine hardener, and the polyetheramine D-230 type hardener used in the present embodiment. The hardener is about 3% to 4% by weight of the epoxy resin composite. The amount of the hardener should correspond to the epoxy resin modified with the terminal carboxyl group polymer, wherein the weight ratio of the terminal carboxyl group-modified epoxy resin to the hardener is about 18 to 20 to 1.

The catalyst is 2-methylimidazole, and the content of the catalyst corresponds to the content of the epoxy resin modified with the terminal carboxyl group. Catalyst in epoxy The weight percentage of the resin composite is from about 1% to about 2%, preferably from about 1.5% to about 1.6%. The solvent is Diethylene glycol monoethyl ether, and the solvent is contained in the epoxy resin composite in an amount of about 25% to 80%, preferably about 28%. The solvent is used to dissolve the other components described above to form a uniform liquid dispersion. The antifoaming agent is used to eliminate the foam in the above epoxy resin composite material, and the defoaming agent is about 0.5% to 1% by weight in the epoxy resin composite material. The antifoaming agent may be a 2183H antifoaming agent produced by the commercially available Taiwan Yuzheng Company.

Preferably, in the epoxy resin composite material, the weight percentage of the epoxy resin modified by the terminal carboxyl group polymer is about 56.0%, the weight percentage of the carbon nanotubes is about 8.5%, and the weight of the inorganic dispersion material is 100%. The content of the component is about 2.2%, the weight percentage of the hardener is about 3.1%, the weight percentage of the catalyst is about 1.6%, the weight percentage of the solvent is about 28.0%, and the weight percentage of the antifoaming agent is about It is 0.6%. The inorganic dispersion material is selected from nano clay. The epoxy resin composite material in this embodiment can have a viscosity of 60,000 to 75,000 centipoise, which can be easily bonded to a cover film or other epoxy resin composite material layer in a circuit board. Preferably, the epoxy resin composite has a viscosity of about 70,000 centipoise.

The technical solution also provides a manufacturing method of the circuit board substrate 100 having the electromagnetic shielding function, and the manufacturing method comprises the following steps: First, the epoxy resin composite material is prepared.

The epoxy resin composite material described in this embodiment can be produced by the following method: First, the epoxy resin is modified with a terminal carboxyl group polymer to obtain an epoxy resin modified with a terminal carboxyl group polymer.

The terminal carboxyl group polymer and the epoxy resin were placed together in a reaction vessel, and the reaction temperature was maintained at 120 ° C, and the reaction was carried out for about 3 hours under stirring to obtain an epoxy resin modified with a terminal carboxyl group polymer. In this embodiment, the epoxy resin used has an epoxy equivalent of about 500. The terminal carboxyl group polymer used may be liquid polybutadiene acrylonitrile (CTBN), and the epoxy resin modified after the reaction has an epoxy equivalent of about 1029. After the above reaction, one epoxy group at the end of the epoxy resin is bonded to one carboxyl group at the terminal of the terminal carboxyl group polymer, and one molecule of water is removed to obtain an ester group. Thus, the modified epoxy resin has good flexibility compared to the epoxy resin which has not been modified. Of course, the epoxy resin used is not limited to the bisphenol A type epoxy resin provided in the embodiment, and may be other types of epoxy resins. The terminal carboxyl group used is not limited to the liquid polybutadiene acrylonitrile provided in the present embodiment, and may be a polymer such as a terminal carboxyl group.

Then, the carbon nanotubes were uniformly dispersed in the inorganic dispersion material to form a uniformly dispersed carbon nanotube dispersion.

The carbon nanotubes are physically dispersed in the inorganic dispersion material. The inorganic dispersion material may be layered nano clay or mica powder. In this embodiment, the inorganic dispersion material selected is a layered nano clay. The carbon nanotubes and the layered nano-clay having a weight ratio of 3 to 4 to 1 are disposed and mixed by stirring or shaking, so that the carbon nanotubes are uniformly dispersed in the layered nano-clay. The layered nano-clay used may be a 2:1 page citrate, which may specifically be smectite, hectorite or saponite. The carbon nanotubes used may be single-walled carbon nanotubes or multi-walled carbon nanotubes.

Finally, the epoxy resin composite modified epoxy resin, carbon nanotube dispersion, solvent, hardener, catalyst and antifoaming agent are mixed and ground to obtain an epoxy resin composite material.

In this embodiment, the terminal carboxyl polymer-modified epoxy resin, the carbon nanotube dispersion, the solvent, the hardener, the catalyst, and the antifoaming agent are ground and dispersed by a three-roller type grinding and dispersing machine. The above-mentioned terminal carboxyl polymer-modified epoxy resin, carbon nanotube dispersion, solvent, hardener, catalyst, and antifoaming agent are put into a three-roll type grinding and dispersing machine according to the respective contents described above, and three-roller type grinding and dispersing is started. The machine is subjected to grinding and dispersion so that the solid components in the above respective compositions are uniformly dispersed in the liquid component, thereby forming a uniformly dispersed epoxy resin composite material. In the present embodiment, among the above components, the weight percentage of the epoxy resin modified with the terminal carboxyl group is about 56.0%, and the weight percentage of the carbon nanotube is about 8.5%, and the weight of the inorganic dispersion material. The percentage is about 2.2%, the weight percentage of the hardener is about 3.1%, the weight percentage of the catalyst is about 1.6%, the weight percentage of the solvent is about 28.0%, and the weight percentage of the antifoaming agent. It is about 0.6%.

In order to obtain an epoxy resin composite material having different surface resistivities, it can be controlled by changing the amount of the carbon nanotube dispersion at the time of feeding. When the carbon nanotubes account for 4.6% to 16% by weight of the composite material, the surface resistivity of the epoxy resin composite varies between about 100,000 ohms and ten ohms. Among them, the larger the content of the carbon nanotubes in the epoxy resin composite material, the smaller the surface resistivity of the epoxy resin composite material.

Referring to FIG. 2 and FIG. 3 together, in the second step, the semi-cured epoxy resin composite material layer 130 is formed by using the epoxy resin composite material.

In this embodiment, the epoxy resin composite material layer 130 is formed by using the epoxy resin composite material as follows.

First, a release substrate layer 20 is provided.

In this embodiment, the release substrate layer 20 is a PET release film having a first release surface. 210.

The epoxy composite is then applied to the first release surface 210 to form an epoxy composite layer 130.

In the present embodiment, a liquid epoxy resin composite material is applied to the first release surface 210 of the release substrate layer 20 by a slit coater to form an epoxy resin composite material layer 130. In the present embodiment, since the coating is performed by a slit coater, the thickness of the formed epoxy resin composite material layer 130 can be controlled to be satisfactory and the coating layer is uniform. In this embodiment, the epoxy resin composite layer 130 is formed to have a thickness of about 8 microns to 12 microns, preferably 10 microns.

Finally, the epoxy resin composite layer 130 coated on the first release surface 210 of the release substrate layer 20 is subjected to a semi-curing treatment to semi-cure the epoxy resin composite layer 130. That is, the semi-cured epoxy resin composite material layer 130 is formed.

In this embodiment, the epoxy resin composite material layer 130 is semi-cured by a prebaking treatment. The duration of prebaking of the epoxy resin composite layer 130 is about 15 minutes, and the temperature maintained during prebaking is about 80 degrees Celsius to 90 degrees Celsius. By performing the prebaking treatment, a part of the solvent in the epoxy resin composite layer 130 is volatilized, so that the epoxy resin composite material layer 130 is in a semi-cured state.

The prebaking duration and the baking temperature can be determined according to the thickness of the actual epoxy resin composite layer 130. When the thickness of the epoxy resin composite layer 130 is large, the baking time can be appropriately extended or baked. The baking temperature is appropriately adjusted, and when the thickness of the epoxy resin composite layer 130 is small, the baking time can be appropriately shortened or the baking temperature can be appropriately lowered to ensure that the epoxy resin composite layer 130 can be semi-cured. Membrane structure.

Referring to FIG. 4, the third step provides a first copper clad plate 101 including a first copper foil layer 110 and a first insulating layer 120.

Referring to FIG. 5, in the fourth step, the epoxy resin composite layer 130 is layered on the first insulating layer 120, and the epoxy resin composite layer 130 is in contact with the first insulating layer 120.

The release substrate layer 20 needs to be removed from the epoxy composite layer 130 prior to subsequent steps. specifically. The release substrate layer 20 may be removed from the epoxy composite layer 130 prior to the epoxy resin composite layer 130 being overlaid on the first insulating layer 120. The release substrate layer 20 may be removed from the epoxy resin composite layer 130 after the epoxy resin composite layer 130 is placed on the first insulating layer 120.

In the fifth step, the epoxy resin composite layer 130 is softened.

In the present embodiment, the temperature at which the epoxy resin composite material layer 130 is softened is 50 degrees Celsius for a period of about 1 minute. Of course, the softening temperature and duration can be adjusted according to the thickness of the epoxy resin composite layer 130. When the thickness of the epoxy resin composite layer 130 is large, the softening temperature or the softening time can be appropriately increased when the epoxy resin is compounded. When the thickness of the material layer 130 is small, the softening temperature or the softening time can be appropriately lowered. By the softening treatment described above, the functional group in the epoxy resin composite material layer 130 which is reacted in the subsequent curing reaction of the epoxy resin composite material layer 130 can further close to the hardener and the catalyst, thereby facilitating the subsequent operation. The curing reaction proceeds.

Referring to FIG. 6, the sixth step, a second copper clad plate 102 including a second copper foil layer 150 and a second insulating layer 140 is provided.

Referring to FIG. 7, the seventh step, the second copper clad laminate 102 is stacked on the epoxy resin composite layer 130, and the second insulating layer 140 is brought into contact with the epoxy resin composite material layer 130.

Referring to FIG. 7 and the eighth step, the first copper clad laminate 101, the epoxy resin composite material layer 130 and the second copper clad laminate 102 are pressed together by roller pressing, so that the epoxy resin composite material layer 130 is cured to obtain The circuit board substrate 100.

In the present embodiment, the first copper clad laminate 101, the epoxy resin composite material layer 130, and the second copper clad laminate 102 are pressed together by using the first roller 31 and the second roller 32 disposed in parallel with each other. The first roller 31 and the second roller 32 may be made of stainless steel. The first roller 31 and the first copper foil layer 110 are in contact with each other, and the second roller 32 and the second copper foil layer 150 are in contact with each other. The distance between the first roller 31 and the second roller 32 is slightly smaller than the first copper clad plate 101 and the ring. The sum of the thicknesses of the oxy-resin composite material layer 130 and the second copper-clad laminate 102. The first roller 31 and the second roller 32 are driven to rotate in opposite directions by a driving device (not shown), so that the first copper clad plate 101 placed in a stack between the first roller 31 and the second roller 32, The epoxy resin composite layer 130 and the second copper clad laminate 102 are pressed together. For press-fitting, the controlled press-fit temperature is about 200 degrees Celsius, the press-fit rate is 0.5 meters per minute, and the pressure at the time of press-bonding is 4 to 5 kilograms per square centimeter.

Moreover, since the epoxy resin used in the present technical solution has a large epoxy equivalent, it contains less functional groups and is softened in the previous step. Under this pressing condition, the functional groups in the epoxy resin composite material layer 130 are sufficiently reacted with the catalyst and the hardener to cure the epoxy resin composite material layer 130 and bond the first insulating layer 120 and the second layer. The insulating layer 140 is obtained to obtain the circuit board substrate 100 as a whole. The circuit board substrate produced by the technical solution can meet the mechanical, chemical, physical and electrical characteristics of IPC-TM-650. Test standard.

The circuit board substrate provided by the technical solution has an epoxy resin composite material layer disposed between adjacent copper foil layers, and the epoxy resin composite material layer has a uniformly dispersed carbon nanotube tube and has an electromagnetic mask. For example, when the two copper foil layers of the circuit board substrate are formed to form a conductive line, the epoxy resin composite material layer can function as an electromagnetic mask. Moreover, the epoxy resin composite layer has good flexibility, and the flexural performance of the flexible circuit board can be increased compared with the prior art stainless steel sheet, and the production cost of the circuit board can be reduced. The method for manufacturing the circuit board substrate provided by the technical solution can realize the curing of the epoxy resin composite material layer by pressing the roller, so that the epoxy resin composite material layer does not need to be matured, thereby saving the circuit. The cost of the board substrate improves the production efficiency of the board substrate.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

100‧‧‧Circuit board

110‧‧‧First copper foil layer

120‧‧‧First insulation

130‧‧‧Epoxy composite layer

140‧‧‧Second insulation

150‧‧‧Second copper foil layer

Claims (7)

A circuit board substrate comprising a first copper foil layer, a first insulating layer, an epoxy resin composite material layer, a second insulating layer and a second copper foil layer stacked in sequence, the epoxy resin composite material layer being epoxy a resin composite material comprising an epoxy resin modified with a terminal carboxyl group polymer, a carbon nanotube and an inorganic dispersion material, wherein the epoxy resin modified by the terminal carboxyl group is a liquid polybutan An acrylonitrile-modified bisphenol A type epoxy resin, wherein the epoxy resin equivalent of the terminal carboxyl group-modified epoxy resin is 950 to 1100, and the carbon nanotube and the inorganic dispersion material are at the terminal carboxyl group The polymer-modified epoxy resin is uniformly dispersed, and the inorganic dispersion material is nano clay or nano mica powder, and the weight ratio of the carbon nanotube to the inorganic dispersion material is 3 to 4 to 1, the nai The weight percentage of the carbon nanotubes in the epoxy resin composite is 4.6% to 16%, and the weight percentage of the epoxy resin modified epoxy resin in the epoxy resin composite is 55% to 65%. The circuit board substrate of claim 1, wherein the epoxy resin composite layer has a thickness of 8 micrometers to 12 micrometers. The circuit board substrate of claim 1, wherein the epoxy resin composite material further comprises a hardener and a catalyst, the hardener is a polyether amine, and the hardener is used in an epoxy resin composite material. The percentage by weight is from 3% to 4%, and the catalyst is 2-methylimidazole, and the catalyst accounts for 1% to 2% by weight of the epoxy resin composite. A method for manufacturing a circuit board substrate, comprising the steps of: preparing an epoxy resin composite material comprising an epoxy resin modified with a terminal carboxyl group polymer, a carbon nanotube and an inorganic dispersion material, the terminal carboxyl group The polymer modified epoxy resin is a liquid polybutadiene acrylonitrile modified bisphenol A type epoxy resin, and the epoxy resin equivalent of the terminal carboxyl polymer modified epoxy resin is 950 to 1100. Carbon nanotubes and inorganic dispersion materials And uniformly dispersed in the terminal carboxyl group polymer modified epoxy resin, wherein the inorganic dispersion material is nano clay or nano mica powder, and the weight ratio of the carbon nanotube to the inorganic dispersion material is 3 to 4 ratio 1. The weight percentage of the carbon nanotubes in the epoxy resin composite material is 4.6% to 16%, and the weight of the terminal carboxyl polymer modified epoxy resin in the epoxy resin composite material a percentage of 55% to 65%; forming an epoxy resin composite layer using the epoxy resin composite material, and semi-curing the epoxy resin composite material layer; providing a first copper foil layer and a first insulating layer a copper clad laminate; an epoxy resin composite layer disposed on a surface of the first insulating layer of the first copper clad laminate; a softening treatment on the epoxy resin composite material layer; providing a second copper foil layer and a second insulating layer a second copper clad layer of the layer; the second copper clad plate is disposed on the surface of the epoxy resin composite material layer, and the second insulating layer is in contact with the epoxy resin composite material layer; and the first copper clad laminate is pressed by a roller Epoxy resin composite The layer and the second copper clad laminate are pressed together, so that the epoxy resin composite material layer is cured and bonded to the first copper clad laminate and the second copper clad laminate to obtain a circuit board substrate. The method for fabricating a circuit board substrate according to claim 4, wherein the preparing the epoxy resin composite material comprises the steps of: modifying the epoxy resin with a terminal carboxyl group polymer to obtain a terminal carboxyl group polymer modification. Epoxy resin; uniformly dispersing a carbon nanotube in the inorganic dispersion material to obtain a carbon nanotube dispersion; and mixing the epoxy resin modified with the terminal carboxyl group with the carbon nanotube dispersion And grinding and dispersing to obtain an epoxy resin composite material. The method for fabricating a circuit board substrate according to claim 5, wherein the epoxy resin composite material is used to form an epoxy resin composite material layer, and the epoxy resin composite is semi-cured. The material layer comprises the steps of: providing a release substrate layer, the release substrate layer having a first release surface; applying the epoxy resin composite to the first release surface of the insulating substrate layer to form an epoxy a resin composite layer; and baking the epoxy resin composite layer until the epoxy resin composite layer is in a semi-cured state. The method for fabricating a circuit board substrate according to claim 6, wherein the epoxy resin composite material layer is self-release substrate layer before the epoxy resin composite material layer is softened. The first release surface is separated.