Low-CTE layer-adding film and preparation method and application thereof

Abstract

The invention belongs to the technical field of IC packaging materials, and relates to a low-CTE layer-adding film and a preparation method and application thereof. The low-CTE layer-adding film is processed from the following raw materials in parts by weight: 3-5 parts of polyphenyl ether containing a methacrylate structure, 40-60 parts of epoxy resin, 40-60 parts of active ester, 50-80 parts of inorganic filler and 0.5-3 parts of a catalyst. The raw material components of the layer-adding film are designed, the modified polyphenyl ether component is innovatively introduced into the raw materials, and the polyphenyl ether of which the end group or the side group is of a methacrylate structure is adopted, so that compared with the conventional combination of epoxy resin and active ester, the thermal expansion coefficient is lower; and the double-bond-containing polyfunctional group active ester and the epoxy resin are further combined and used, so that two cross-linking reaction mechanisms exist in the system at the same time, the cross-linking density can be effectively improved, and the thermal expansion coefficient is further reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of IC packaging materials and relates to a low CTE build-up layer film and a preparation method and application thereof. Background Art

[0002] Build-up films are an indispensable key material in advanced packaging technology and play a vital role in improving the overall performance of electronic packaging. The main raw materials for build-up films currently used in the market include epoxy resins, phenolic resins, cyanate esters, and active esters. Among them, the thermosetting resin system composed of active esters and epoxy resins does not produce additional hydroxyl groups (-OH) during the chemical reaction, which gives it the characteristics of low dielectric loss and low water absorption, meeting the high standards for electrical performance of the new generation of build-up films; in addition, the combination system of active esters and epoxy resins also exhibits excellent film-forming properties, heat resistance and chemical stability, providing reliable guarantees for high-performance electronic packaging.

[0003] Polyphenylene ether (PPO) material is a high-performance thermoplastic engineering plastic, which is composed of multiple benzene rings connected by oxygen atoms and has a unique molecular structure. In recent years, polyphenylene ether has been favored in the application of high-frequency and high-speed copper-clad laminates due to its excellent dielectric properties, thermal stability and low thermal expansion coefficient. Chinese patent CN118240516A discloses a build-up film for FC-BGA package carrier containing modified polyphenylene ether and its preparation method and application. Modified polyphenylene ether is introduced into the active ester and epoxy resin system, but the amino polyphenylene ether and / or carboxylated polyphenylene ether used will cause the electrical properties of the build-up film material to deviate. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention provides a low CTE build-up layer film and a preparation method and application thereof.

[0005] To achieve the above-mentioned object, the present invention provides a low CTE build-up layer film, which is processed from raw materials including the following parts by weight: 3 to 5 parts of polyphenylene ether containing methacrylate structure, 40 to 60 parts of epoxy resin, 40 to 60 parts of active ester, 50 to 80 parts of inorganic filler, and 0.5 to 3 parts of catalyst.

[0006] The total weight of the polyphenylene ether containing a methacrylate structure, the epoxy resin and the active ester is 100 parts.

[0007] Preferably, the polyphenylene ether containing a methacrylate structure includes a polyphenylene ether with a methacrylate structure as a terminal group and / or a polyphenylene ether with a methacrylate structure as a side group;

[0008] The terminal group of the polyphenylene ether is a methacrylate structure, and has a structural formula of Formula I or Formula II:

[0009] Formula I;

[0010] Formula II;

[0011] The side group is a polyphenylene ether with a methacrylate structure and has a structural formula of Formula III or Formula IV:

[0012] Formula III;

[0013] Formula IV;

[0014] Wherein, X is selected from one or more of substituted or unsubstituted benzene ring, substituted or unsubstituted naphthalene ring, substituted or unsubstituted biphenyl, substituted or unsubstituted alicyclic hydrocarbon, substituted or unsubstituted naphthyl ether, substituted or unsubstituted bisphenol A, substituted or unsubstituted dicyclopentadiene, substituted or unsubstituted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group (DOPO);

[0015] R1, R2, R3, R4, R5 are selected from one or more of H, substituted or unsubstituted C1-C10 straight chain alkyl, substituted or unsubstituted C1-C10 branched chain alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C6-C14 aryl, substituted or unsubstituted heteroaryl;

[0016] 1≤n≤10, 1≤m≤10.

[0017] More preferably, in the formula I, R1=R2, and in the formula II, R3=R4=R5, which can ensure excellent dielectric properties.

[0018] More preferably, R3, R4, and R5 are selected from one or more of H, C1-C3 straight-chain alkyl, and C1-C3 branched-chain alkyl, which can reduce the steric hindrance effect of the reaction.

[0019] More preferably, 1≤n≤5, 1≤m≤5.

[0020] Preferably, in the structural formula of the polyphenylene ether whose side groups are methacrylate structures, the mass ratio of the methacrylate structure is 5-30%.

[0021] Preferably, the epoxy resin includes one or more of naphthalene ring type epoxy resin, bisphenol type epoxy resin, biphenyl type epoxy resin, naphthol type epoxy resin, linear phenolic type epoxy resin, dicyclopentadiene type epoxy resin, aralkyl type phenolic epoxy resin, aralkyl biphenyl type phenolic epoxy resin, and naphthol type phenolic epoxy resin.

[0022] Preferably, the active ester comprises a linear active ester, and the linear active ester comprises one or more of bisphenol A type active ester, bisphenol M type active ester, bisphenol F type active ester, dicyclopentadiene type active ester, biphenyl type active ester, naphthalene type active ester, and phenolic type active ester.

[0023] More preferably, the active ester includes 1-10 parts of branched active ester containing double bonds and 30-50 parts of linear active ester. If too much branched active ester containing double bonds is added, the steric hindrance effect will be too large, resulting in inhibition of the crosslinking reaction and reduction of the crosslinking density.

[0024] Preferably, the structural formula of the double-bond-containing branched active ester is as shown in Formula V:

[0025] Formula V;

[0026] Wherein, Y is selected from one or more of substituted or unsubstituted C1-C10 straight chain alkyl, substituted or unsubstituted C1-C10 branched chain alkyl, substituted or unsubstituted C3-C10 cycloalkyl; preferably, it is substituted or unsubstituted C1-C3 straight chain alkyl.

[0027] Preferably, the inorganic filler includes one or more of silica, alumina, glass, cordierite, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate, calcium zirconate, and zirconium phosphate.

[0028] Preferably, the catalyst comprises 0.5-2.0 parts of a first catalyst and 0.1-1.5 parts of a second catalyst, wherein the first catalyst is used to catalyze the reaction between the active ester and the epoxy group, and the second catalyst is used to catalyze the free radical reaction.

[0029] Preferably, the first catalyst includes one or more of pyridine catalysts, imidazole catalysts, pyrimidine catalysts, and thiazole catalysts. Further preferably, the first catalyst includes one or more of 4-dimethylaminopyridine, 1-ethyl-2-methylimidazole, 1-tert-butyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-ethyl-4-methylimidazole, 1,8-diazacyclo[5,4,0]undecene-7, and 2,4,6-tris(dimethylaminomethyl)phenol.

[0030] Preferably, the second catalyst is a peroxidation catalyst, including one or more of dicumyl peroxide, dibenzoyl peroxide, cyclohexanone peroxide, tert-butyl peroxide, cumene hydroperoxide, and lauroyl peroxide.

[0031] Preferably, the raw materials of the build-up film further include 0.5 to 5 parts of an auxiliary agent and 200 to 300 parts of a solvent.

[0032] The auxiliary agent is not particularly limited, and any auxiliary agent that can be used in the build-up film to improve its function can be used, and can be listed as one or more of a thickener, a defoamer, a leveling agent, a leveling agent, an adhesion-imparting agent, a colorant, and the like.

[0033] The solvent is not particularly limited, as long as it can dissolve the reaction raw materials, and can be one or more of butanone, tetrahydrofuran, N,N-dimethylformamide, cyclohexanone, chloroform, dichloromethane, ethyl acetate, toluene, isopropanol, N-methylpyrrolidone, methyl isobutyl ketone, methyl ethyl ketone, etc.

[0034] The present invention also provides a method for preparing a low CTE build-up film, which comprises the following steps: uniformly mixing the above-mentioned build-up film raw materials to obtain a build-up film slurry, coating the slurry on a substrate, and drying to obtain the low CTE build-up film.

[0035] Preferably, the drying temperature is 60-130° C., and the drying time is 1-60 min.

[0036] The selection of the substrate is not particularly limited, and any substrate commonly used in the art can be used, which can be one or more of PET film, polyethylene film, polypropylene film, polyvinyl chloride film, etc.

[0037] The present invention also provides an application of a low CTE build-up layer film, including application in integrated circuit packaging.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. The present invention provides a low CTE build-up film, which designs the raw material components of the build-up film, innovatively introduces a modified polyphenylene ether component into the raw material, and combines the use of a branched active ester containing a double bond, thereby effectively solving the problem of high CTE of current build-up film materials.

[0040] 2. In a low CTE build-up film provided by the present invention, a polyphenylene ether having a methacrylate structure as an end group or a side group and a branched active ester containing a double bond are used as a curing agent. First, the methacrylate structure of the modified polyphenylene ether and the active ester group and epoxy group in the curing agent can react under the catalysis of a first catalyst to generate an alkyl ester group to form a partial crosslink, and then the double bonds in the system will undergo a free radical reaction under the catalysis of a second catalyst, thereby further improving the crosslinking density of the system, and finally constructing an interconnected network structure with two crosslinking modes.

[0041] 3. The present invention provides a low CTE build-up film, which reduces the thermal expansion coefficient CTE of the build-up film by introducing modified polyphenylene ether. Polyphenylene ether itself has a lower CTE than epoxy resin and active ester. Secondly, the two cross-linking reaction mechanisms that exist simultaneously in the system effectively increase the cross-linking density and further achieve a reduction in the thermal expansion coefficient. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is further described below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

[0043] The raw materials used in the following examples and comparative examples are as follows:

[0044] Polyphenylene ether with methacrylate end group: NORYL SA9000 from SABIC;

[0045] The structure of the branched active ester containing double bonds is as follows:

[0046] ;

[0047] The preparation method of the above-mentioned branched active ester containing double bonds comprises the following steps: taking 0.31 mol of acetyl chloride and diluting it with tetrahydrofuran to 0.015 mol / ml, then adding it dropwise to a mixed solution of 0.1 mol of resveratrol and 1.8 mol of triethylamine, reacting at 6°C for 10 hours in a nitrogen atmosphere, precipitating the reaction product in a mixed system of water and ethanol (the volume ratio of water to ethanol is 1:3), washing the solid product obtained after filtration with ethanol, and storing it for later use after vacuum drying at 60°C. The specific reaction formula is as follows:

[0048] ;

[0049] Linear active ester: DIC's HPC-8000-65T;

[0050] Naphthalene ring epoxy resin: DIC's HP-6000;

[0051] Inorganic filler: silica powder (spherical silica), SO-C2 from Yaduma, D50 = 0.5 μm;

[0052] Leveling agent: DIC's GRANDIC PC4100;

[0053] Substrate: LUMIRROR R80 38µm from Toray.

[0054] Example 1

[0055] The low CTE build-up film of this embodiment is made of the following raw materials in parts by weight: 5 parts of polyphenylene ether with a methacrylate end group, 55 parts of epoxy resin, 10 parts of branched active ester containing double bonds, 30 parts of linear active ester, 70 parts of silicon powder, 1 part of 4-dimethylaminopyridine, 0.5 parts of diisopropylbenzene peroxide, 3 parts of leveling agent, and 250 parts of solvent (tetrahydrofuran and butanone mixed in a ratio of 2:1).

[0056] The preparation method of the low CTE build-up film of this embodiment includes the following steps: uniformly mixing the above-mentioned build-up film raw materials to obtain a build-up film slurry, coating the slurry on a substrate, and drying at 80° C. for 10 min to obtain the low CTE build-up film.

[0057] Example 2

[0058] The low CTE build-up film of this embodiment is made of the following raw materials in parts by weight: 5 parts of polyphenylene ether with a methacrylate structure as a side group, 55 parts of epoxy resin, 10 parts of branched active ester containing double bonds, 30 parts of linear active ester, 70 parts of silicon powder, 1 part of 4-dimethylaminopyridine, 0.5 parts of diisopropylbenzene peroxide, 3 parts of leveling agent, and 250 parts of solvent (tetrahydrofuran and butanone mixed in a ratio of 2:1).

[0059] Among them, in the polyphenylene ether with a methacrylate structure as the side group, the mass ratio of the methacrylate structure is 10%, and the structural formula is as follows:

[0060] ;

[0061] Where n=3, m=3, and the polyphenylene ether 1 is recorded as a methacrylate structure with a side group.

[0062] The preparation method of the low CTE build-up layer film is the same as that of Example 1.

[0063] Example 3

[0064] The low CTE build-up film of this embodiment is made of the following raw materials in parts by weight: 3 parts of polyphenylene ether with a methacrylate structure as a side group, 57 parts of epoxy resin, 5 parts of branched active ester containing double bonds, 35 parts of linear active ester, 65 parts of silicon powder, 0.8 parts of 1-ethyl-2-methylimidazole, 0.7 parts of dibenzoyl peroxide, 3 parts of leveling agent, and 250 parts of solvent (N, N-dimethylformamide and butanone mixed in a ratio of 2:1).

[0065] Wherein, the side group is a polyphenylene ether with a methacrylate structure, the mass ratio of the methacrylate structure is 15%, and the structural formula is as follows:

[0066] ;

[0067] Where n=5, m=5, and is recorded as polyphenylene ether 2 having a methacrylate structure as the side group.

[0068] The preparation method of the low CTE build-up layer film is the same as that of Example 1.

[0069] Example 4

[0070] The difference between this embodiment and embodiment 1 is that no branched active ester containing double bonds is used in the raw materials.

[0071] The low CTE build-up layer film of this embodiment is made of the following raw materials in parts by weight: 5 parts of polyphenylene ether with a methacrylate structure as a side group, 50 parts of epoxy resin, 45 parts of linear active ester, 70 parts of silicon powder, 1 part of 4-dimethylaminopyridine, 0.5 parts of diisopropylbenzene peroxide, 3 parts of leveling agent, and 250 parts of solvent (tetrahydrofuran and butanone mixed in a ratio of 2:1).

[0072] The polyphenylene ether having a methacrylate structure as the side group is the same as that in Example 1.

[0073] The preparation method of the low CTE build-up layer film is the same as that of Example 1.

[0074] Comparative Example 1

[0075] The difference between this comparative example and Example 1 is that an excessive amount of polyphenylene ether having a methacrylate structure as a side group is used in the raw material.

[0076] The build-up layer film of this comparative example is made from the following raw materials in parts by weight: 10 parts of polyphenylene ether with a methacrylate structure as a side group, 52 parts of epoxy resin, 10 parts of branched active ester containing double bonds, 28 parts of linear active ester, 70 parts of silicon micropowder, 1.0 part of 4-dimethylaminopyridine, 0.5 part of diisopropylbenzene peroxide, 3 parts of leveling agent, and 250 parts of solvent (N,N-dimethylformamide and butanone mixed in a ratio of 2:1).

[0077] The polyphenylene ether having a methacrylate structure as the side group is the same as that in Example 1.

[0078] The preparation method of the above-mentioned build-up layer film is the same as that of Example 1.

[0079] Comparative Example 2

[0080] The difference between this comparative example and Example 1 is that no polyphenylene ether containing a methacrylate structure is used in the raw material.

[0081] The low CTE build-up film of this comparative example is made from the following raw materials in parts by weight: 58 parts of epoxy resin, 10 parts of branched active ester containing double bonds, 32 parts of linear active ester, 70 parts of silicon micropowder, 1 part of 4-dimethylaminopyridine, 0.5 parts of diisopropylbenzene peroxide, 3 parts of leveling agent, and 250 parts of solvent (tetrahydrofuran and butanone mixed in a ratio of 2:1).

[0082] The preparation method of the above-mentioned build-up layer film is the same as that of Example 1.

[0083] Comparative Example 3

[0084] The difference between this comparative example and Example 1 is that the polyphenylene ether containing a methacrylate structure and the branched active ester containing a double bond are not used in the raw materials.

[0085] The low CTE build-up film of this comparative example is made from the following raw materials in parts by weight: 57 parts of epoxy resin, 43 parts of linear active ester, 70 parts of silicon powder, 1 part of 4-dimethylaminopyridine, 0.5 parts of diisopropylbenzene peroxide, 3 parts of leveling agent, and 250 parts of solvent (tetrahydrofuran and butanone mixed in a ratio of 2:1).

[0086] The preparation method of the above-mentioned build-up layer film is the same as that of Example 1.

[0087] The raw material components of the build-up films of the above-mentioned embodiments and comparative examples are set as shown in Table 1.

[0088] Table 1 Raw material composition of build-up film in the examples and comparative examples

[0089] .

[0090] The thermodynamic properties and dielectric properties of the build-up films obtained from the above application examples and the application comparison examples were tested, and the specific test methods are as follows:

[0091] 1. Thermal expansion coefficient: The obtained build-up film was cured at 190°C for 90 minutes, and then the substrate was peeled off to obtain a test sample; the test sample was cut into a test piece with a width of 2 mm and a length of 17 mm, and a thermomechanical analysis device was used to test in the pull-up mode, with a preload force of 0.02N, a temperature rise range of 25°C~260°C, and a temperature rise rate of 5°C / min. The thermal mechanical analysis was performed to obtain the thermal expansion coefficient in the range of 25°C to 150°C;

[0092] 2. Glass transition temperature: The obtained build-up film was cured at 190°C for 90 minutes, and then the substrate was peeled off to obtain a test sample; the test sample was cut into a test piece with a width of 6 mm and a length of 15 mm, and tested using a dynamic thermomechanical analysis device in tensile mode. The test conditions were set to a vibration frequency of 1 Hz, an amplitude of 15 μm, a heating rate of 5°C / min, and a heating range of 25°C~260°C to obtain the glass transition temperature Tg;

[0093] 3. Dielectric constant: The obtained build-up film was cured at 190°C for 90 minutes, and then the substrate was peeled off to obtain a test sample; the test sample was cut into a test piece of 51mm×69mm, and after being stored at 23±(1~5)°C and 50±5% relative humidity for 16 hours, the dielectric constant of the test piece was measured using the stripline method at a measurement frequency of 10GHz and a measurement temperature of 22~24°C;

[0094] 4. Loss factor: The obtained build-up film was cured at 190°C for 90 minutes, and then the substrate was peeled off to obtain a test sample; the test sample was cut into a test piece of 80 mm × 80 mm, and after being stored at 23±(1~5)°C and 50±5% relative humidity for 16 hours, the loss factor of the test piece was measured using the resonant cavity method at a measurement frequency of 10 GHz and a measurement temperature of 22~24°C;

[0095] The specific test results are shown in Table 2.

[0096] Table 2 Performance test data of examples and comparative examples

[0097] .

[0098] As shown in Table 2, it can be seen from Examples 1 to 4 that the build-up film prepared by the technical solution of the present invention exhibits excellent thermodynamic properties and dielectric properties after being applied to the packaging carrier, ensuring the performance of the build-up film in the field of integrated circuit packaging; the methacrylate structure of the modified polyphenylene ether introduced and the active ester group and epoxy group in the curing agent can react under the catalysis of the first catalyst to generate an alkyl ester group to form a partial crosslink, and then the double bonds in the system will undergo a free radical reaction under the catalysis of the second catalyst, thereby further improving the crosslinking density of the system, and finally constructing an interconnected network structure with two crosslinking modes to achieve excellent performance of high Tg and low CTE; in Example 4, the side chain active ester containing double bonds is not used, which can also play a role in increasing Tg and reducing CTE, but the overall effect is slightly lower than that of Example 1; in Comparative Example 1, an excessive amount of polyphenylene ether containing a methacrylate structure is used, resulting in failure to form a film; in Comparative Examples 2 to 3, when the polyphenylene ether containing a methacrylate structure and / or the side chain active ester containing double bonds are not used, the overall performance is greatly reduced and cannot reach the level of the examples.

[0099] The various aspects, embodiments, and features of the present invention should be considered to be illustrative in all aspects and not limiting of the present invention, the scope of which is defined solely by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0100] In the preparation method of the present invention, the order of each step is not limited to the order listed. For those skilled in the art, without creative work, the order of each step is also within the protection scope of the present invention. In addition, two or more steps or actions can be performed simultaneously.

[0101] Finally, it should be noted that the specific embodiments described herein are merely examples of the present invention, and are not intended to limit the implementation methods of the present invention. A person skilled in the art of the present invention may make various modifications or supplements to the specific embodiments described, or replace them in a similar manner. It is not necessary and impossible to provide all examples of all implementation methods here. However, these obvious changes or modifications derived from the essential spirit of the present invention still fall within the scope of protection of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A low CTE build-up film, characterized in that: The low CTE build-up layer film is made of the following raw materials in parts by weight: 3-5 parts of polyphenylene ether containing a methacrylate structure, 40-60 parts of epoxy resin, 40-60 parts of active ester, 50-80 parts of inorganic filler, and 0.5-3 parts of catalyst; The polyphenylene ether containing a methacrylate structure includes a polyphenylene ether with a methacrylate structure as an end group and / or a polyphenylene ether with a methacrylate structure as a side group; The terminal group of the polyphenylene ether is a methacrylate structure, and has a structural formula of Formula I or Formula II: Formula I; Formula II; The side group is a polyphenylene ether with a methacrylate structure and has a structural formula of Formula III or Formula IV: Formula III; Formula IV; Wherein, X is selected from one or more of substituted or unsubstituted benzene ring, substituted or unsubstituted naphthalene ring, substituted or unsubstituted biphenyl, substituted or unsubstituted alicyclic hydrocarbon, substituted or unsubstituted naphthyl ether, substituted or unsubstituted bisphenol A, substituted or unsubstituted dicyclopentadiene, substituted or unsubstituted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group; R1, R2, R3, R4, R5 are selected from one or more of H, substituted or unsubstituted C1-C10 straight chain alkyl, substituted or unsubstituted C1-C10 branched chain alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C6-C14 aryl, substituted or unsubstituted heteroaryl; 1≤n≤10, 1≤m≤10.

2. A low CTE build-up layer film according to claim 1, characterized in that: The total weight of the polyphenylene ether containing a methacrylate structure, the epoxy resin and the active ester is 100 parts.

3. The low CTE build-up layer film according to claim 1, characterized in that: The active ester includes linear active ester, and the linear active ester includes one or more of bisphenol A type active ester, bisphenol M type active ester, bisphenol F type active ester, dicyclopentadiene type active ester, biphenyl type active ester, naphthalene type active ester and phenolic type active ester.

4. The low CTE build-up layer film according to claim 1, characterized in that: The active ester includes 1 to 10 parts of branched active ester containing double bonds and 30 to 50 parts of linear active ester.

5. The low CTE build-up layer film according to claim 4, characterized in that: The structural formula of the double-bond-containing branched active ester is shown in Formula V: Formula V; Wherein, Y is selected from one or more of substituted or unsubstituted C1-C10 straight-chain alkyl, substituted or unsubstituted C1-C10 branched-chain alkyl, and substituted or unsubstituted C3-C10 cycloalkyl.

6. The low CTE build-up layer film according to claim 1, characterized in that: The catalyst includes 0.5 to 2.0 parts of a first catalyst and 0.1 to 1.5 parts of a second catalyst.

7. The low CTE build-up layer film according to claim 6, characterized in that: The first catalyst includes one or more of a pyridine catalyst, an imidazole catalyst, a pyrimidine catalyst, and a thiazole catalyst; And / or, the second catalyst is a peroxide catalyst.

8. The low CTE build-up layer film according to claim 1, characterized in that: The epoxy resin includes one or more of naphthalene ring epoxy resin, bisphenol epoxy resin, biphenyl epoxy resin, naphthol epoxy resin, linear phenolic epoxy resin, dicyclopentadiene epoxy resin, aralkyl phenolic epoxy resin, aralkyl biphenyl phenolic epoxy resin, and naphthol phenolic epoxy resin; And / or, the inorganic filler includes one or more of silica, alumina, glass, cordierite, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate, calcium zirconate, and zirconium phosphate.

9. A method for preparing a low CTE build-up layer film according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: uniformly mixing the above-mentioned build-up film raw materials to obtain build-up film slurry, coating the slurry on a substrate, and drying to obtain the low CTE build-up film.

10. Use of a low CTE build-up layer film according to any one of claims 1 to 8 in integrated circuit packaging.

Images