TWI411658B - Composite adhesive film, adhesive sheet and method for manufacturing the same - Google Patents

Abstract

This disclosure relates to a composite adhesive film. The film has a first contacting surface. The film includes a polymer matrix, a number of thermally conductive particles, and a number of carbon fibers. The carbon fibers are substantially perpendicular to the first contacting surface. An average length of the carbon fibers is in the range of 80%-110% of the thickness of the film. The particles are positioned between the carbon fibers, and an average diameter of the particles is in the range of 70%-90% of the thickness of the film. The matrix connects between the carbon fibers and the particles, and a viscosity of the matrix is from 8000 cps to 18000 cps. An adhesive sheet including the above-mentioned film and a method for manufacturing the sheet are also provided.

Description

Composite adhesive sheet, film and film manufacturing method

The invention relates to adhesive technology, in particular to a composite adhesive sheet having better thermal conductivity, a film comprising the composite adhesive sheet and a method for manufacturing the same.

With the advancement of science and technology, printed circuit boards are 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, 15(4): 418-425.

As the integration of circuit boards increases, circuit boards often emit a large amount of heat during actual operation. If heat is not exported in time, it will affect the signal transmission of the board. One method of accelerating the heat dissipation of a circuit board product is to use a thermally conductive film having thermal conductivity when mounting or integrating electronic components on the circuit board. At present, the thermal conductivity of the commonly used thermal film is not fast enough, and the thermal conductivity is not uniform enough.

In view of the above, it is necessary to provide a composite adhesive sheet having superior thermal conductivity and thermal conductivity, a film including the composite adhesive sheet, and a method of manufacturing the same.

Hereinafter, a composite adhesive sheet, a film including the composite adhesive sheet, and a method of producing the same will be described by way of examples.

A composite adhesive sheet having a first contact surface for contacting an object to be bonded. The composite adhesive sheet comprises a resin matrix, a plurality of thermally conductive particles, and a plurality of carbon fibers. The plurality of carbon fibers are substantially perpendicular to the first contact surface, and the average length of the plurality of carbon fibers is from 80% to 110% of the thickness of the composite adhesive sheet. The plurality of thermally conductive particles are located between the plurality of carbon fibers, and the average particle diameter of the plurality of thermally conductive particles is from 70% to 90% of the thickness of the composite adhesive sheet. The resin matrix is distributed between the plurality of thermally conductive particles and between the plurality of carbon fibers, and the viscosity of the resin matrix is from 8,000 cps to 18,000 cps.

A film comprising a first release substrate and a composite adhesive sheet. The first release substrate has a first release surface, and the composite adhesive sheet is formed on the first release surface. The composite adhesive sheet comprises a resin matrix, a plurality of thermally conductive particles, and a plurality of carbon fibers. The plurality of carbon fibers are substantially perpendicular to the first release surface, and the average length of the plurality of carbon fibers is from 80% to 110% of the thickness of the composite adhesive sheet. The plurality of thermally conductive particles are located between the plurality of carbon fibers, and the average particle diameter of the plurality of thermally conductive particles is from 70% to 90% of the thickness of the composite adhesive sheet. The resin matrix is connected between the plurality of thermally conductive particles and between the plurality of carbon fibers, and the resin matrix has a viscosity of from 8,000 cps to 18,000 cps.

A method of manufacturing a film, comprising the steps of: providing a composite adhesive material comprising a resin matrix, a plurality of thermally conductive particles, and a plurality of carbon fibers, wherein the plurality of thermally conductive particles are located between a plurality of carbon fibers, and the resin matrix is connected to the plurality of carbon fibers Between thermally conductive particles and between plural carbon fibers; Providing a first release substrate, the first release substrate having a first release surface; applying the composite adhesive material to the first release surface to cause the composite adhesive material to be in a first separation The coating thickness of the surface is 91% to 125% of the average length of the plurality of carbon fibers, and is 111% to 143% of the average particle diameter of the plurality of thermally conductive particles; and stretching the release substrate and heating and coating the first The composite adhesive material of the release surface is such that the carbon fibers in the composite adhesive material coated on the first release surface extend substantially in a direction perpendicular to the first release surface, and the resin matrix is cured to a viscosity of 8000. From centipoise to 18,000 centipoise to form a composite adhesive sheet.

The composite adhesive sheet provided by the technical solution has a plurality of heat conductive particles and a plurality of carbon fibers dispersed therein. Since carbon fiber has excellent thermal conductivity, its thermal conductivity is generally 300~500W/k, which can improve the thermal conductivity and thermal conductivity of the composite adhesive sheet. Moreover, the average length of the plurality of carbon fibers is 80% to 110% of the thickness of the composite adhesive sheet, and is substantially vertically arranged, so that the heat radiated from the heat source can be conducted as soon as possible after being attached to the surface of the circuit board or the surface of other heat source members. Further, a plurality of heat conductive particles are further distributed between the plurality of carbon fibers, and the average particle diameter of the plurality of heat conductive particles is 70% to 90% of the thickness of the composite adhesive sheet, thereby assisting to conduct heat emitted from the heat source. Moreover, the resin matrix also has good adhesion so that it can adhere well to the surface of the heat source. The film provided by the technical solution has good thermal conductivity and thermal conductivity. The film manufacturing method provided by the technical solution can prepare the above film having excellent thermal conductivity and thermal conductivity.

10‧‧‧ Film

11‧‧‧First release substrate

110‧‧‧First release surface

12‧‧‧Composite adhesive sheet

1201‧‧‧First contact surface

1202‧‧‧Second contact surface

122‧‧‧ carbon fiber

124‧‧‧thermal particles

13‧‧‧Second release substrate

130‧‧‧Separate release surface

1 is a schematic cross-sectional view of a film including a composite adhesive sheet provided by an embodiment of the present technical solution.

2 is a flow chart of a method for fabricating a film provided by an embodiment of the present technical solution.

The composite adhesive sheet provided by the technical solution, the film comprising the composite adhesive sheet and the manufacturing method of the film will be further described in detail below with reference to the accompanying drawings and embodiments.

Referring to FIG. 1 , the technical solution provides a film 10 including a first release substrate 11 , a composite adhesive sheet 12 and a second release substrate 13 which are sequentially stacked.

The first release substrate 11 is used to carry the composite adhesive sheet 12. The first release substrate 11 refers to a sheet material having at least one release surface, and the release surface is a surface having a low surface energy, which can adhere to other materials and easily separate the material adhered thereto. The first release substrate 11 may be a PET release film, that is, the substrate is PET, and at least one surface of the substrate is coated with a material such as eucalyptus oil to form a sheet-like material of a release surface, thereby being able to adhere. The composite adhesive sheet 12 is formed thereon, but it is easy to separate the first release substrate 11 from the composite adhesive sheet 12. In the present embodiment, the first release substrate 11 is a single-sided PET release film having a first release surface 110 in contact with the composite adhesive sheet 12. The material of the first release substrate 11 is not limited to the PET release film provided in the embodiment, and may be other materials having a release surface such as a release paper or the like. The release paper may be slick paper or coated paper.

The second release substrate 13 is used to protect the composite adhesive sheet 12. The film 10 may not include the second release substrate 13 when the produced film 10 does not need to be transported or stored for a long time. The material of the second release substrate 13 may be the same as that of the first release substrate 11, that is, it may be a PET release film, and may be other materials having a release surface, such as various release papers and the like. The second release substrate 13 has a second release surface 130 that is in contact with the composite adhesive sheet 12. The second release surface 130 is substantially parallel to the first release surface 110 and The distance between the two release surfaces 130 and the first release surface 110 is the thickness of the composite adhesive sheet 12.

During the transportation and storage process, the first release substrate 11 and the second release substrate 13 can isolate the composite adhesive sheet 12 from the outside, preventing the composite adhesive sheet 12 from being contaminated or absorbing moisture. When the plurality of films 10 are stacked on each other during transportation or storage, the first release substrate 11 and the second release substrate 13 may also isolate adjacent films 10 to prevent the films 10 from sticking to each other.

The composite adhesive sheet 12 is used for bonding to the surface of the heat source component, and functions to bond other components and conduct heat radiated from the heat source component. The thickness of the composite adhesive sheet 12 can be set according to actual needs. In this embodiment, the composite adhesive sheet 12 has a thickness of about 50 microns. The composite adhesive sheet 12 is disposed between the first release surface 110 of the first release substrate 11 and the second release surface 130 of the second release substrate 13. The composite adhesive sheet 12 has a first contact surface 1201 and a second contact surface 1202. The second contact surface 1202 is in contact with the first release substrate 11 for being attached to the component to be bonded and in contact with the component to be bonded after being separated from the first release substrate 11 . The first contact surface 1201 is in contact with the second release substrate 13 for being attached to the component to be bonded and in contact with the component to be bonded after being separated from the second release substrate 13 . The distance between the first contact surface 1201 and the second contact surface 1202 is the thickness of the composite adhesive sheet 12, that is, about 50 microns. The composite adhesive sheet 12 is composed of a composite adhesive material. The composite adhesive material includes at least a resin matrix, a plurality of carbon fibers 122 and a plurality of thermally conductive particles 124, and may further include other materials, for example, a curing agent, a catalyst, a solvent, a toughening agent, an additive, and an antifoaming agent. The plurality of carbon fibers 122 are substantially uniformly distributed in the composite adhesive material, and the plurality of thermally conductive particles 124 are substantially uniform in the composite adhesive material. distributed. Moreover, the plurality of carbon fibers 122 and the plurality of thermally conductive particles 124 are doped with each other, that is, the plurality of carbon fibers 122 are located between the plurality of thermally conductive particles 124, and the plurality of thermally conductive particles 124 are located between the plurality of carbon fibers 122. The resin matrix and other materials are used to join and bond the plurality of carbon fibers 122 and the plurality of thermally conductive particles 124.

The resin matrix may be in a cured state or a semi-cured state, and has a viscosity of 8000 mPa. s (mPa.second) to 18000mPa. s, ie 8000 centipoise (cps) to 18000 centipoise, preferably 11000 mPa. s to 14000mPa. s. The resin matrix may be an epoxy resin or other resin such as Polyimide (PI), Polyethylene Terephthalate (PET), polyethylene naphthalate. (Polyethylene naphthalate, PEN) and the like. In this embodiment, the resin matrix is a commercially available Dow 331 liquid epoxy resin, which is a liquid product formed by reacting epichlorohydrin with bisphenol A, and having an epoxy equivalent of 182 to 192. Preferably it is about 188. Of course, the resin matrix may also be other modified epoxy resins, for example, a product obtained by copolymerization of an epoxy resin with a terminal carboxyl group polymer, that is, an epoxy group terminal and an epoxy group terminal end. The carboxyl group reacts to form an ester group, thereby obtaining a polymer comprising alternating repeating units of the epoxy resin repeating unit and the terminal carboxyl group polymer. The epoxy resin is present in the composite adhesive material in an amount of from about 10% to about 18% by weight, preferably about 14.03%.

The plurality of carbon fibers 122 are each substantially perpendicular to the first contact surface 1201 and extend substantially from the first contact surface 1201 or near the first contact surface 1201 to the second contact surface 1202 or near the second contact surface 1202. The average length of the plurality of carbon fibers 122 is from 80% to 110% of the thickness of the composite adhesive sheet 12. In this embodiment, the average length of the plurality of carbon fibers 122 is substantially equal to the thickness of the composite adhesive sheet 12, which is about 50 microns. . Of the plurality of carbon fibers 122, at least a portion of the carbon fibers 122 are exposed to the first contact surface 1201, and at least a portion of the carbon fibers 122 are exposed to the second contact surface 1202. Or it can be said that in the plurality of carbon fibers 122, part of the carbon fibers 122 are exposed to both the first contact surface 1201 and the second contact surface 1202; some of the carbon fibers 122 are neither exposed to the first contact surface 1201 nor exposed to the first The second contact surface 1202; a portion of the carbon fibers are only exposed to the first contact surface 1201 without being exposed to the second contact surface 1202; and a portion of the carbon fibers are only exposed to the second contact surface 1202 without being exposed to the first contact surface 1201. The carbon fiber 122 may be a microcrystalline graphite material obtained by carbonizing and graphitizing the organic fiber, or may be a one-dimensional carbon material such as a carbon nanotube, a carbon nanowire, a nanocarbon cluster or a graphene. In this embodiment, the carbon fiber 122 is present in the composite adhesive material in an amount of about 8% to 12% by mass, preferably about 9.82%.

The plurality of thermally conductive particles 124 may be spherical, ellipsoidal, approximately spherical, approximately ellipsoidal or of other shapes. The average particle diameter of the plurality of thermally conductive particles 124 is 70% to 90% of the thickness of the composite adhesive sheet 12. Alternatively, it may be 70% to 90% of the average length of the plurality of carbon fibers 122. Preferably, the average particle diameter of the plurality of thermally conductive particles 124 is about 80% of the thickness of the composite adhesive sheet 12. The average particle diameter refers to the equivalent diameter of the largest particle when the cumulative distribution in the particle size distribution curve is 50%. In the present embodiment, the thermally conductive particles 124 have an average particle size of about 40 microns, about 50% of the thermally conductive particles 124 have a particle size of less than or equal to 40 microns, and 5% of the thermally conductive particles 124 have a particle size of about 50 microns. In this embodiment, the thermally conductive particles 124 are made of boron nitride (BN) particles. Of course, the thermally conductive particles 124 may also be made of alumina, silver or other materials having a higher thermal conductivity. The thermally conductive particles 124 comprise from 35% to 55% by weight of the composite adhesive material, preferably about 44.91%.

The hardener is used to harden the composite adhesive material. In the present embodiment, the hardener used is dicyandiamine, and the hardener is present in the composite adhesive material in an amount of 1.0% to 2.0% by mass, preferably about 1.57%. In the composite adhesive material, the total active hydrogen of the hardener can be equivalent to the total amount of epoxy of the epoxy resin.

The catalyst is 2-Phenylimidazole, and the content of the catalyst corresponds to the content of the epoxy resin. The catalyst accounts for about 0.16% by mass of the composite adhesive.

The solvent is Diethylene glycol monoethyl ether acetate, and the solvent is contained in the composite adhesive material in an amount of 10% to 30%, preferably about 21.05%. This solvent is used to dissolve the other components described above to form a homogeneous liquid dispersion.

The toughening agent is a poly-hydroxylether of Bisphenol A (PKHH), and the toughening agent is contained in the composite adhesive material in an amount of from 2.0% to 6.5%, preferably about 4.21%. The content of the toughening agent corresponds to the content of the solvent. The mass ratio of the toughening agent to the solvent is from about 0.1 to 0.3 to 1, preferably from 0.2 to 1.

The additive is used to alleviate the drawing phenomenon that occurs when the toughening agent is dissolved in a solvent. The additive is gamma-Glycid oxypropy tri-methoxy silane, and the additive is present in the composite adhesive material in an amount of about 0.74%.

The antifoaming agent is used for eliminating foam in a composite adhesive material, and the defoaming agent is compounded The mass percentage of the adhesive material is about 2% to 5%. It is preferably 3.51%. The defoaming agent can be a commercially available 1211 defoaming agent produced by Taiwan Yuzheng Co., Ltd., which can also function as a leveling agent in the composite adhesive material.

In the film of a preferred embodiment provided by the technical solution, in the composite adhesive material for forming the composite adhesive sheet 12, the mass percentage of the epoxy resin is about 14.03%, and the mass percentage of the plurality of carbon fibers 122 is about 9.82%, the mass percentage of the plurality of thermally conductive particles 124 is about 44.91%, the mass percentage of dicyandiamide is about 1.57%, and the mass percentage of 2-phenylimidazole is about 0.16%, diethylene glycol. The mass percentage of monoethyl ether acetate is about 21.05%, the mass percentage of bisphenol A polyhydroxy ether is about 4.21%, and the mass percentage of γ-glycidyloxypropyl trimethoxy decane is about 0.74%, the mass percentage of the antifoaming agent is about 3.51%.

Of course, those skilled in the art can understand that in the composite adhesive material for forming the composite adhesive sheet 12, in addition to the resin matrix, the plurality of carbon fibers 122 and the plurality of heat conductive particles 124, other hardeners, catalysts, solvents, toughening agents, Additives and defoamers are not essential technical features and may contain only one or more of them, and may also include other materials. For example, the composite adhesive material can include a resin matrix, a plurality of carbon fibers 122, and a plurality of thermally conductive particles 124 and a solvent.

When the film 10 provided by the technical solution is applied to the surface of the circuit board or other heat source surface, the second release substrate 13 may be first peeled off, thereby exposing the first contact surface 1201 of the composite adhesive sheet 12, which will be first The contact surface 1201 is in contact with the surface of the circuit board or other heat source surface to adhere and adhere the composite adhesive sheet 12 to the surface of the circuit board or other heat source surface, and then the first release substrate 11 can be removed from the composite adhesive sheet 12 The second contact surface 1202 is removed. In this way, the composite adhesive sheet 12 can be attached and adhered to the electricity. The surface of the road board or other heat source surface has the effect of bonding and heat conduction.

After being applied to the surface of the circuit board or other heat source surface, the composite adhesive sheet 12 is substantially gray, and has good adhesion, solvent resistance and acid and alkali resistance. Specifically, after the composite adhesive sheet 12 is attached to the surface of the circuit board or other heat source surface, it is immersed in the acetone solution for 17 hours without peeling off, and immersed in a sodium hydroxide or hydrochloric acid solution having a concentration of 10% for half an hour. There is no slight peeling phenomenon.

Referring to FIG. 1 and FIG. 2 together, the technical solution further provides a method for manufacturing the film 10, and the manufacturing method comprises the following steps: First, providing a composite adhesive material. The composite adhesive material is a material constituting the composite adhesive sheet 12 as described above, and includes at least a resin matrix, a plurality of carbon fibers 122, and a plurality of heat conductive particles 124. The plurality of carbon fibers 122 are located between the plurality of thermally conductive particles 124. The plurality of thermally conductive particles 124 are located between the plurality of carbon fibers 122. The resin matrix may be an epoxy resin connected between the plurality of thermally conductive particles 124 and between the plurality of carbon fibers 122. . The average particle size of the plurality of thermally conductive particles 124 can be between 70% and 90% of the average length of the plurality of carbon fibers 122. In the present embodiment, the plurality of carbon fibers 122 have an average length of about 50 microns, and the plurality of thermally conductive particles 124 have an average particle size of about 40 microns.

The composite adhesive material may also include other materials. In this embodiment, the composite adhesive material further includes a hardener, a catalyst, a solvent, a toughening agent, an additive, and an antifoaming agent. These materials may all be used as described above and may have the amounts as previously described. For example, the solvent may be diethylene glycol monoethyl ether acetate as described above, and the solvent may be contained in the composite adhesive material in an amount of 10% to 30%.

In a second step, a first release substrate 11 is provided, the first release substrate 11 having a first release surface 110. The first release substrate 11 may be a PET release film.

In a third step, the composite adhesive material is applied to the first release surface 110, and the coating thickness of the composite adhesive material on the first release surface 110 is 91% to 125 of the average length of the plurality of carbon fibers 122. %, and is from 111% to 143% of the average particle diameter of the plurality of thermally conductive particles 124. Thereby, the average length of the plurality of carbon fibers 122 is from 80% to 110% of the coating thickness, and the average particle diameter of the plurality of thermally conductive particles is from 70% to 90% of the coating thickness. In this embodiment, the composite adhesive material has a coating thickness of about 50 microns on the first release surface 110.

In this embodiment, a liquid composite adhesive material is applied to the first release surface 110 of the first release substrate 11 by a slit coater to facilitate control of the coating thickness and uniform coating.

In the fourth step, the first release substrate 11 is stretched, and the composite adhesive material coated on the first release surface 110 is heated to make the plurality of composite adhesive materials applied to the first release surface 110 The carbon fibers 122 all extend substantially perpendicular to the first release surface 110 and cause the resin matrix to cure to a viscosity of from 8,000 centipoise to 18,000 centipoise to form the composite adhesive sheet 12. The composite adhesive sheet 12 has a first contact surface 1201 and a second contact surface 1202 opposite to each other, and the second contact surface 1202 is in contact with the first release surface 110 of the first release substrate 11.

In this embodiment, stretching the first release substrate 11 and heating the composite adhesive material applied to the first release surface 110 to form the composite adhesive sheet 12 may include the following steps: First, the first release substrate 11 is stretched, and the composite adhesive material applied to the first release surface 110 is baked at a temperature of about 80-120 degrees Celsius for about 2-4 minutes. In the present embodiment, the composite adhesive material applied to the first release surface 110 is baked at a temperature of about 100 degrees Celsius for about 3 minutes while stretching. The tensile force of the first release substrate 11 and the polarity of the solvent will cause the plurality of carbon fibers 122 in the composite adhesive material to substantially stand on the first release surface 110. That is, the plurality of carbon fibers 122 will be substantially perpendicular to the first release surface 110.

Next, the first release substrate 11 is stopped from being stretched, and the composite adhesive material applied to the first release surface 110 is baked at a temperature of about 60-80 degrees Celsius for about 4-8 minutes. In the present embodiment, the composite adhesive material applied to the first release surface 110 is baked at a temperature of about 70 degrees Celsius for about 5 minutes. At this time, the resin matrix, the solvent, and other materials may be further cured so that the resin matrix is cured to a viscosity of 8,000 cps to 18,000 cps.

Those skilled in the art will appreciate that the conditions of stretching and the conditions of heating may depend on the composition and thickness of the composite adhesive material. In actual operation, the parameters of stretching and heating can be determined according to specific conditions.

In the fifth step, the second release substrate 13 is attached to the surface of the composite adhesive sheet 12 away from the first release substrate 11, that is, on the first contact surface 1201. The second release substrate 13 has a second release surface 130 , and the composite adhesive sheet 12 is adhered to the first release surface 110 and the second release substrate 13 of the first release substrate 11 . Between the second release surfaces 130. The second release substrate 13 may be a release PET film, which may be a variety of release papers.

When the formed film 10 is directly used for circuit board production, it is also on the composite adhesive sheet. The second release substrate 13 may not be attached.

After the fourth or fifth step, the film 10 can be further cut to form the film 10 into a desired shape for ease of use. When the formed film 10 is not directly applied, the film 10 can be stored in a low temperature environment, and the storage temperature can be about 5 degrees Celsius.

The composite adhesive sheet 12 provided by the technical solution uniformly disperses a plurality of heat conductive particles 124 and a plurality of carbon fibers 122. Since the carbon fiber has excellent thermal conductivity, its thermal conductivity is generally 300 to 500 W/k, so that the thermal conductivity and thermal conductivity of the composite adhesive sheet 12 can be improved. Moreover, the average length of the plurality of carbon fibers 122 is 80% to 110% of the thickness of the composite adhesive sheet 12, and is substantially vertically arranged, so that when the surface of the circuit board or other heat source elements is attached, the heat source can be radiated as soon as possible. Heat. Further, a plurality of heat conductive particles 124 are further distributed between the plurality of carbon fibers 122. The average particle diameter of the plurality of heat conductive particles 124 is 70% to 90% of the thickness of the composite adhesive sheet 12, so as to assist in conducting heat emitted from the heat source. Moreover, the resin matrix also has good adhesion so that it can adhere well to the surface of the heat source. That is, the composite adhesive sheet 12 can be stably attached to the surface of the heat source and has a faster heat dissipation efficiency. The film manufacturing method provided by the technical solution can prepare the above film 10 having excellent thermal conductivity and thermal conductivity.

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.

10‧‧‧ Film

11‧‧‧First release substrate

110‧‧‧First release surface

12‧‧‧Composite adhesive sheet

1201‧‧‧First contact surface

1202‧‧‧Second contact surface

122‧‧‧ carbon fiber

124‧‧‧thermal particles

13‧‧‧Second release substrate

130‧‧‧Separate release surface

Claims (11)

A composite adhesive sheet having a first contact surface for contacting an object to be pasted, the composite adhesive sheet comprising a resin matrix, a plurality of thermally conductive particles, and a plurality of carbon fibers, the quality of the resin matrix in the composite adhesive sheet The content of the plurality of carbon fibers in the composite adhesive sheet is 8% to 12%, and the mass percentage of the plurality of thermally conductive particles in the composite adhesive sheet is 35%. Up to 55%, the plurality of carbon fibers are substantially perpendicular to the first contact surface, and the average length of the plurality of carbon fibers is 80% to 110% of the thickness of the composite adhesive sheet, and the plurality of thermally conductive particles are located between the plurality of carbon fibers, and the plurality of heat conduction The average particle diameter of the particles is 70% to 90% of the thickness of the composite adhesive sheet. The resin matrix is distributed between the plurality of thermally conductive particles and between the plurality of carbon fibers, and the viscosity of the resin matrix is 8,000 cps to 18,000 cps. The composite adhesive sheet of claim 1, wherein at least a portion of the plurality of carbon fibers are exposed to the first contact surface. The composite adhesive sheet according to claim 1, wherein the resin matrix is an epoxy resin having an epoxy equivalent of 182 to 192, and the epoxy resin has a viscosity of 11,000 cps to 14000 cps. The composite adhesive sheet according to claim 1, wherein the material of the plurality of thermally conductive particles is boron nitride. The composite adhesive sheet according to claim 1, wherein the composite adhesive sheet further comprises a hardener, a catalyst, a solvent, a toughening agent, an additive, and an antifoaming agent. The composite adhesive sheet according to claim 5, wherein the hardener is dicyandiamide, and the hardener is 1.0% by mass in the composite adhesive sheet. Up to 2.0%, the catalyst is 2-phenylimidazole, the solvent is diethylene glycol monoethyl ether acetate, and the solvent is 10% to 30% by mass in the composite adhesive material, The toughening agent is a bisphenol A type polyhydroxy ether, the toughening agent is contained in the composite adhesive material in a mass percentage of 2.0% to 6.5%, and the additive is γ-glycidyloxypropyl trimethoxy group. The decane has a mass percentage of 2% to 5% in the composite adhesive material. A film comprising a first release substrate and a composite adhesive sheet according to any one of claims 1 to 76, the first release substrate having a first release surface, the composite adhesive sheet further There is a second contact surface opposite the first contact surface, the second contact surface being in contact with the first release surface. The film of claim 7, wherein the film further comprises a second release substrate, the second release substrate has a second release surface, the first contact surface and the The second release surface is in contact. The film of claim 7, wherein one of the plurality of carbon fibers is exposed to the first contact surface and the other end is exposed to the second contact surface. A method of fabricating a film, comprising the steps of: providing a composite adhesive material comprising an epoxy resin matrix, a plurality of thermally conductive particles, and a plurality of carbon fibers, wherein the plurality of thermally conductive particles are located between a plurality of carbon fibers, the epoxy resin The substrate is connected between the plurality of thermally conductive particles and between the plurality of carbon fibers, wherein the resin matrix has a mass percentage of 10% to 18% in the composite adhesive sheet, and the mass percentage of the plurality of carbon fibers in the composite adhesive sheet The content is 8% to 12%, the mass percentage of the plurality of thermally conductive particles in the composite adhesive sheet is 35% to 55%; and the first release substrate is provided, the first release substrate has the first Release surface Applying the composite adhesive material to the first release surface, so that the coating thickness of the composite adhesive material on the first release surface is 91% to 125% of the average length of the plurality of carbon fibers, and is a plurality of heat conduction 111% to 143% of the average particle diameter of the particles; and stretching the first release substrate and heating the composite adhesive material coated on the first release surface to make the composite coated on the first release surface The carbon fibers in the adhesive material extend substantially perpendicular to the first release surface, and the resin matrix is cured to a viscosity of 8,000 centipoise to 18,000 centipoise to form a composite adhesive sheet. The method for producing a film according to claim 10, wherein the forming the composite adhesive sheet comprises the steps of: stretching the first release substrate and baking the first release surface at a first temperature; The composite adhesive material continues for a first time; and the stretching of the first release substrate is stopped, and the composite adhesive material coated on the first release surface is baked at a second temperature for a second time, the first temperature Above the second temperature, the second time is longer than the first time.