An epoxy build-up adhesive film glue, a preparation method and application thereof, and an epoxy build-up composite adhesive film, a preparation method and application thereof

Abstract

The present application relates to the technical field of chip packaging materials, in particular to a kind of epoxy build-up adhesive film glue, epoxy build-up composite adhesive film and its preparation method and application.The present application uses epoxy resin+active ester reaction system as basic system, and uses naphthalene epoxy resin, alkenyl-containing benzoxazine resin, benzocyclobutene resin and polyimide resin, resin containing epoxy group and olefin bond), modified silica (alkenyl siloxane modified silica) type, cooperate with peroxide initiator, catalyst, dispersing agent, leveling agent and solvent, under the synergistic effect of above-mentioned each component, the compatibility between resin can be optimized and the reaction degree of pre-curing is reduced, form uniform, roughness suitable epoxy build-up adhesive film surface, provide physical interface for the formation of high copper foil peel force.The epoxy build-up adhesive film glue and the epoxy build-up adhesive film formed by the present application have ultra-low dielectric loss and high copper foil peel strength.

Description

Technical Field

[0001] This invention relates to the field of chip packaging materials technology, specifically to an epoxy thickening adhesive film, its preparation method and application, and an epoxy thickening composite film, its preparation method and application. Background Technology

[0002] With the rise of AI applications, the packaging requirements for products such as CPUs and GPUs are becoming increasingly stringent. Miniaturization, low loss, and high reliability have become fundamental packaging requirements. Flip-chip ball grid array (FC-BGA) packaging substrates have become the future development direction for semiconductor packaging substrates, with wide applications and broad market prospects. FC-BGA packaging substrates are high-density packaging substrates capable of enabling high-speed and multi-functional chips. To achieve the fine circuitry requirements of 10μm / 10μm (linewidth / linegap) in FC-BGA circuitry, low dielectric loss and high copper foil peel strength of the additive manufacturing process (SAP) have become one of the key materials for FC-BGA packaging substrates. Its dielectric loss has decreased year by year from 0.015 to 0.008, 0.004, and 0.002.

[0003] To achieve a dielectric loss of 0.004 or even 0.002 for the adhesive film, and to ensure the peel strength between the adhesive film and the copper foil, the mainstream technology involves selecting a resin system of low-dielectric epoxy resin and reactive ester. After the adhesive film is pre-cured (e.g., pre-cured at 130°C for 30 minutes), the substrate undergoes processes such as resin fluffing, chemical etching for copper deposition, electroplating, and post-curing to form fine circuitry. However, the reaction between the low-dielectric epoxy resin and the reactive ester is relatively rapid under the action of the catalyst 4-dimethylaminopyridine (DMAP), with a curing degree generally exceeding 90%. The resin layer is difficult to etch to a suitable roughness through the chemical etching process, thus failing to provide the mechanical bonding force necessary for subsequent high copper foil peel strength.

[0004] To provide a suitable roughness, a resin with low dielectric loss and low reactivity (such as epoxy-modified polyphenylene ether resin) is usually added to the system. However, the low polarity of this resin makes it difficult to be fully compatible with low dielectric epoxy resin and reactive ester reaction system, resulting in a very uneven etched morphology, which ultimately fails to improve the copper foil peel strength. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide an adhesive for epoxy layering films, its preparation method, and its application, as well as an epoxy layering composite film, its preparation method, and its application. The epoxy layering adhesive and the epoxy layering film formed therefrom provided by this invention exhibit ultra-low dielectric loss and high copper foil peel strength.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides an adhesive for epoxy thickening films, comprising, by weight parts: 36-45 parts epoxy resin, 17-25 parts reactive ester curing agent, 10-15 parts alkenyl benzoxazine resin, 5-9 parts benzocyclobutene resin, 7-12 parts polyimide resin, 1.9-2.8 parts compatibilizer, 250-280 parts modified silica, 0.9-1.6 parts peroxide initiator, 0.3-0.6 parts catalyst, 1.5-2.6 parts dispersant, 3.6-5.5 parts leveling agent, and solvent; The epoxy resin includes naphthalene-based epoxy resin; The compatibilizer is a resin containing epoxy groups and olefin bonds; The modified silica is obtained by modifying silica with olefin-containing siloxanes.

[0007] Preferably, the active ester curing agent includes one or more of the following: active ester curing agents containing biphenyl structures, active ester curing agents containing polycyclic aromatic hydrocarbon structures, and dicyclopentadiene; the weight-average molecular weight of the active ester curing agent is 1600~4300. The alkenylbenzoxazine-containing resin includes allylbenzoxazine resin and / or vinylbenzoxazine resin; The weight-average molecular weight of the polyimide resin is 20,000 to 55,000.

[0008] Preferably, the olefin-containing siloxane includes one or more of vinyltriisopropoxysilane, vinylmethyldiethoxysilane, vinylmethyldimethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, and 3-methacryloyloxypropyltrimethoxysilane; The mass of the olefin-containing siloxane is 0.8-1.1% of the mass of silicon dioxide; The particle size D of the silicon dioxide 50 3~7μm, D 90 It is 8~15μm.

[0009] Preferably, the 1-hour half-life temperature of the peroxide initiator is 90~140℃; The catalyst includes 4-dimethylaminopyridine; The solvent includes one or more of toluene, cyclopentanone, and cyclohexanone; The viscosity of the adhesive used for the epoxy laminate film is 600~1900 mPa·s.

[0010] The present invention also provides a method for preparing the adhesive for epoxy thickening films described in the above technical solution, comprising the following steps: The alkenyl benzoxazine resin, benzocyclobutene resin, compatibilizer, modified silica and solvent were ball-milled and mixed to obtain a slurry; The slurry is mixed with an initiator and reacted under a protective atmosphere to obtain a reactive slurry; The reaction slurry, epoxy resin, reactive ester curing agent, polyimide resin solution, dispersant and leveling agent are first dispersed and emulsified to obtain the initial adhesive. The initial adhesive is further dispersed and emulsified with the catalyst, and then a solvent is added to adjust the viscosity to obtain an adhesive for epoxy thickening films.

[0011] Preferably, the reaction temperature is 90~130℃ and the time is 5~8h; The rotation speed of the first dispersion emulsification is 2000~3000 r / min, and the time is 2~3 h; The second dispersion emulsification is carried out at a rotation speed of 2000~3000 r / min for a time of 20~30 min.

[0012] The present invention also provides an epoxy thickening composite film, comprising a carrier layer, an epoxy thickening film and a protective layer stacked sequentially; the epoxy thickening film is prepared by the epoxy thickening film adhesive described in the above technical solution or the epoxy thickening film adhesive prepared by the preparation method described in the above technical solution.

[0013] Preferably, the material of the support layer includes polyethylene terephthalate, and the thickness of the support layer is 38~50μm; The thickness of the epoxy laminate film is 15~110μm; The protective layer is made of polypropylene; the thickness of the protective layer is 25~45μm.

[0014] The present invention also provides a method for preparing the epoxy layered composite film described in the above technical solution, comprising the following steps: After applying an epoxy thickening film to the surface of the carrier layer with adhesive and drying it, an epoxy thickening layer is formed on the surface of the carrier layer. The protective layer is pressed onto the epoxy thickening film to obtain an epoxy thickening composite film.

[0015] The present invention also provides the application of the epoxy thickening adhesive film described in the above technical solution, the epoxy thickening adhesive film prepared by the preparation method described in the above technical solution, the epoxy thickening composite film described in the above technical solution, or the epoxy thickening composite film prepared by the preparation method described in the above technical solution in chip packaging.

[0016] This invention uses an epoxy resin + reactive ester reaction system as the basic system. By optimizing the resin type (naphthalene-based epoxy resin, alkenyl benzoxazine resin, benzocyclobutene resin, and polyimide resin), compatibilizer type (resin containing epoxy groups and alkenyl bonds), and modified silica type (silica modified with alkenyl siloxanes), and by using peroxide initiators, catalysts, dispersants, leveling agents, and solvents, the compatibility between resins is optimized and the degree of pre-curing reaction is reduced under the synergistic effect of the above components. This results in a uniform epoxy layered film surface with suitable roughness, providing a physical interface for the formation of high copper foil peel strength. When this epoxy layered film adhesive is used for chip packaging, during the post-curing process after copper plating and substrate electroplating, some resin continues to undergo post-curing reaction under high temperature conditions, further improving the copper foil peel strength. The epoxy layered film adhesive and the epoxy layered film formed by this invention exhibit ultra-low dielectric loss and high copper foil peel strength.

[0017] This invention uses naphthalene-based epoxy resin, which inherently possesses excellent low dielectric loss, as the main epoxy resin, enabling the epoxy laminate adhesive and the resulting epoxy laminate film to exhibit low dielectric loss. During the chip packaging process of this invention, the reaction temperature of the alkenyl benzoxazine resin with the epoxy resin is ≥160℃, thereby fully utilizing the subsequent curing process of the cured product to enhance the adhesion between the epoxy resin film and the copper foil. The introduction of alkenyl benzoxazine resin slightly increases the dielectric loss of the epoxy laminate adhesive and the resulting epoxy laminate film. This invention, by adding low dielectric loss benzocyclobutene resin, can further reduce the dielectric loss of the cured product. Naphthalene-based epoxy resin systems are generally brittle, and film cracking defects easily occur during the peeling process. This invention, by adding polyimide resin, can improve the flexibility of the epoxy laminate film while maintaining its low dielectric properties. In epoxy resin-based systems, although epoxy resin and reactive ester curing agents have low polarity, their compatibility with alkenyl benzoxazine and benzocyclobutene resins differs due to polarity differences. This invention significantly improves the compatibility between resins by adding resins containing epoxy groups and alkenyl bonds as compatibilizers. In epoxy thickening adhesive systems, filler stability is a key factor determining the surface uniformity after etching. While modifying silica with N-phenyl-3-aminopropyltrimethoxysilane can improve the reaction between the modified silica filler and epoxy resin, this method cannot ensure the stability of the modified silica filler during etching, easily leading to poor surface uniformity. To address these shortcomings, this invention uses silica modified with alkenyl siloxanes, which significantly improves the stability of the modified silica filler in epoxy thickening adhesive systems while ensuring good reactivity, preventing sedimentation and resulting in a more uniform and controllable epoxy thickening film surface after etching. The epoxy thickening adhesive and the epoxy thickening film formed therefrom provided by the present invention have ultra-low dielectric loss and high copper foil peel strength.

[0018] As shown in the test results of the examples, the curing thermal expansion coefficient α1 of the epoxy laminate film prepared by the present invention is 16~20, and the curing thermal expansion coefficient α2 is 37~43; the dielectric properties (10GHz) D k The value is 2.32~2.41, D f The value is 0.00238~0.00267; the copper foil peel strength is 0.46~0.51Kgf / cm; the lowest dynamic viscosity is 1609~2201 foil, and the temperature corresponding to the lowest dynamic viscosity is 119~131℃; the epoxy reinforcing film has good appearance smoothness, no low polarity benzocyclobutene precipitation, and uniform chemical etching. Attached Figure Description

[0019] Figure 1 SEM image of the cured epoxy thickening film prepared in Example 1 after chemical etching; Figure 2 SEM image of the cured epoxy laminate film prepared in Example 2 after chemical etching; Figure 3 SEM image of the cured epoxy thickened film prepared in Example 3 after chemical etching; Figure 4 SEM image of the cured epoxy laminate film prepared in Example 4 after chemical etching; Figure 5 SEM image of the cured epoxy thickened film prepared in Example 5 after chemical etching; Figure 6 SEM image of the cured epoxy thickened film prepared in Example 6 after chemical etching; Figure 7 SEM image of the cured epoxy laminate film prepared in Comparative Example 1 after being etched by chemical solution; Figure 8 SEM image of the cured epoxy laminate film prepared in Comparative Example 2 after chemical etching; Figure 9 SEM image of the cured epoxy laminate film prepared in Comparative Example 3 after being chemically etched. Detailed Implementation

[0020] This invention provides an adhesive for epoxy thickening films, comprising, by weight parts: 36-45 parts epoxy resin, 17-25 parts reactive ester curing agent, 10-15 parts alkenyl benzoxazine resin, 5-9 parts benzocyclobutene resin, 7-12 parts polyimide resin, 1.9-2.8 parts compatibilizer, 250-280 parts modified silica, 0.9-1.6 parts peroxide initiator, 0.3-0.6 parts catalyst, 1.5-2.6 parts dispersant, 3.6-5.5 parts leveling agent, and solvent; The epoxy resin includes naphthalene-based epoxy resin; The compatibilizer is a resin containing epoxy groups and olefin bonds; The modified silica is obtained by modifying silica with olefin-containing siloxanes.

[0021] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0022] Based on parts by weight, the epoxy thickening adhesive provided by this invention comprises 36-45 parts of epoxy resin, which can be 37-44 parts, or 38-43 parts, specifically 36, 37, 38, 39, 40, 41, 42, 43, 44, or 45 parts. In this invention, the epoxy resin includes naphthalene-based epoxy resins, specifically one or more of ESN-4100VEK75 (Nippon Steel), ESN-475V (Nippon Steel), NC-7000-L (Nippon Chemical), NC-7000-H (Nippon Chemical), NPTE714 (Hunan Jiashengde), DIC HP4710, HP4700, and HP-4032D, specifically one, two, or three types. In a specific embodiment of the present invention, the epoxy resin may be a first composite epoxy resin composed of ESN-4100VEK75, NPTE714 and HP-4032D, or a second composite epoxy resin composed of ESN-475V, NC-7000-H and HP-4032D, or a third composite epoxy resin composed of ESN-4100VEK75, NC-7000-H and HP4700, or a fourth composite epoxy resin composed of ESN-4100VEK75, ESN-475V and NPTE714; the mass ratio of ESN-4100VEK75, NPTE714 and HP-4032D in the first composite epoxy resin may be 10~18:8~12:18, specifically 15:12:18, 10:9:18 or 15:8:18; The mass ratio of ESN-475V, NC-7000-H, and HP-4032D in the second compound epoxy resin can be 11~13:11~14:18, or 11~12:11~13:18, specifically 11:12:18; the mass ratio of ESN-4100VEK75, NC-7000-H, and HP4700 in the third compound epoxy resin can be 14~17:11~14:12, or 15~16:11~13:12, specifically 15:12:12; the mass ratio of ESN-4100VEK75, ESN-475V, and NPTE714 in the fourth compound epoxy resin can be 13~16:9~11:12, or 15~16:9~10:12, specifically 15:9:12.

[0023] This invention uses naphthalene-based epoxy resin, which has good low dielectric loss, as the main epoxy resin, which enables the epoxy thickening film adhesive and the epoxy thickening film formed therefrom to have low dielectric loss.

[0024] Based on the mass fraction of the epoxy resin, the epoxy layering adhesive provided by the present invention comprises 17-25 parts of an active ester curing agent, which can be 18-24 parts, 19-23 parts, or specifically 20 parts, 21 parts, or 22 parts. In the present invention, the weight-average molecular weight of the active ester curing agent can be 1600-4300, which can be 2000-4000, further 2500-3500, or specifically 3000; the active ester curing agent can include one or more of the following: active ester curing agents containing biphenyl structures, active ester curing agents containing polycyclic aromatic hydrocarbon structures, and dicyclopentadiene, and can specifically include one or more of HPC-8150-60T (Japan DIC), HPC-8000-65T (Japan DIC), TEH8803 (Guangdong Tongyu), and AEB-1000-65T (Anhui Mituo), and can specifically include one, two, three, or four types. In a specific embodiment of the present invention, the active ester curing agent may specifically include a first compound active ester curing agent composed of HPC-8000-65T and AEB-1000-65T, or a second compound active ester curing agent composed of TEH8803 and HPC-8000-65T, or a third compound active ester curing agent composed of TEH8803 and AEB-1000-65T, or a fourth compound active ester curing agent composed of HPC-8000-65T and HPC-8150-60T; the mass ratio of HPC-8000-65T to AEB-1000-65T in the first compound active ester curing agent may be 9:10~1. 4. Specifically, the ratio can be 9:10 or 9:14; the mass ratio of TEH8803 and HPC-8000-65T in the second compound active ester curing agent can be 11:10~14, or 11:11~13, specifically 11:12; the mass ratio of TEH8803 and AEB-1000-65T in the third compound active ester curing agent can be 11:13~17, specifically 11:14; the mass ratio of HPC-8000-65T and HPC-8150-60T in the fourth compound active ester curing agent can be 9~12:15, or 9.5~11:15, specifically 10:15. This invention, by adding an active ester curing agent, allows for a transesterification curing reaction with a low-dielectric naphthalene-based epoxy resin under heating conditions, without generating additional hydroxyl structures. The resulting epoxy resin cured product has a dielectric loss value D. f Low.

[0025] Based on the mass fraction of the epoxy resin, the epoxy coating adhesive provided by this invention comprises 10-15 parts, 11-14 parts, or 12-13 parts of an alkenyl benzoxazine resin. In this invention, the alkenyl benzoxazine resin may include allyl benzoxazine resin and / or vinyl benzoxazine resin; the allyl benzoxazine resin may include one or more of DFE148 (Sichuan Dongcai, solid content 70%), DFE165 (Sichuan Dongcai, solid content 70%), and CB6472K70 (Keyi), specifically one or two. This invention utilizes the reaction temperature of the alkenyl benzoxazine resin with the epoxy resin (≥160℃) to fully utilize the subsequent curing process of the cured product to enhance the adhesion between the epoxy resin film and the copper foil.

[0026] Based on the mass fraction of the epoxy resin, the epoxy coating adhesive provided by this invention comprises 5-9 parts, 6-8 parts, or 7 parts of benzocyclobutene resin. In this invention, the benzocyclobutene resin may include one or more of BR-2000 (Anhui Mito), DS5106 (Disai New Materials), and DS5204 (Disai New Materials). The introduction of alkenyl benzoxazine resin slightly increases the dielectric loss of the epoxy coating adhesive and the epoxy coating formed therefrom. This invention, by adding a low-dielectric-loss benzocyclobutene resin, can further reduce the dielectric loss of the cured product.

[0027] Based on the mass fraction of the epoxy resin, the epoxy layering adhesive provided by the present invention comprises 7-12 parts, 8-11 parts, or 9-10 parts of polyimide resin. In the present invention, the weight-average molecular weight of the polyimide resin can be 20,000-55,000, or 30,000-40,000. In the present invention, the polyimide resin may include one or more of PMR-1000 (Anhui Mito), PAID 150L (Arakawa Chemical), PAID 2000 (Arakawa Chemical), PAID 300C (Arakawa Chemical), and PIAD152H (Arakawa Chemical), specifically one, two, three, four, or five types. In this invention, the polyimide resin can be used in the form of a polyimide resin solution, wherein the solvent in the polyimide resin solution is the same type as the solvent in the adhesive for the epoxy laminate film; the solid content of the polyimide resin solution can be 65-70%, specifically 65%, 66%, 67%, 68%, 69%, or 70%. Naphthalene-based epoxy resin systems are generally brittle and prone to cracking during the peeling process. This invention, by adding polyimide resin, can improve the flexibility of the epoxy laminate film while maintaining low dielectric properties. Adding polyimide resin with a weight-average molecular weight of 20,000-55,000 is even more effective in improving the flexibility of the epoxy laminate film and reducing its dielectric loss performance.

[0028] Based on the mass fraction of the epoxy resin, the epoxy layering adhesive provided by the present invention comprises 1.9 to 2.8 parts of compatibilizer, which can be 2 to 2.7 parts, or 2.1 to 2.6 parts, specifically 1.9 parts, 2.0 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts, 2.5 parts, 2.6 parts, 2.7 parts, or 2.8 parts. In the present invention, the compatibilizer is a resin containing epoxy groups and olefin bonds, and may include one or more of JP-100 (Japan Soda), Kics22-ly-002 (USA Corten), and EPOLEADPB3600 (Japan Grandeur), specifically one, two, or three types. In epoxy resin-based systems, although epoxy resin and reactive ester curing agents have low polarity, they differ in polarity from alkenyl benzoxazine resins and benzocyclobutene resins, resulting in less than ideal compatibility. This invention significantly improves the compatibility between resins by adding resins containing epoxy groups and alkenyl bonds as compatibility agents.

[0029] Based on the mass fraction of the epoxy resin, the epoxy layering adhesive provided by this invention comprises 250-280 parts of modified silica, and may also be 255-270 parts, specifically 255 parts, 259 parts, 264 parts, 265 parts, 269 parts, or 274 parts. In this invention, the modified silica is obtained by modifying silica with an olefin-containing siloxane. In this invention, the particle size D of the silica is... 50 The particle size D of the silica can be 3~7μm or 4~6μm. 90 The silica can be 8-15 μm or 10-12 μm; the silica can be spherical silica. In this invention, the olefin-containing siloxane can include one or more of vinyltriisopropoxysilane, vinylmethyldiethoxysilane, vinylmethyldimethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, and 3-methacryloyloxypropyltrimethoxysilane, specifically one, two, three, four, five, six, or seven types; the mass of the olefin-containing siloxane can be 0.8-1.1% of the mass of silica, specifically 0.9-1%. In this invention, the modification temperature can be 60-80℃ or 65-75℃, specifically 70℃; the modification time can be 3-4 hours, specifically 3.5 hours; the modification can be carried out under stirring conditions.

[0030] In epoxy coating adhesive systems, the stability of the filler is a key factor determining the surface uniformity of the film after etching. While modifying silica with N-phenyl-3-aminopropyltrimethoxysilane can improve the reactivity between the modified silica filler and the epoxy resin, this method struggles to ensure the stability of the modified silica filler during etching, easily leading to poor surface uniformity. To address these shortcomings, this invention uses silica modified with olefin-containing siloxanes. This significantly improves the stability of the modified silica filler in epoxy coating adhesive systems while maintaining good reactivity, resulting in a more uniform and controllable surface uniformity of the etched epoxy coating.

[0031] Based on the mass fraction of the epoxy resin, the epoxy layering adhesive provided by the present invention comprises 0.9 to 1.6 parts of peroxide initiator, which can be 1 to 1.5 parts, or 1.1 to 1.4 parts, specifically 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, or 1.6 parts. In the present invention, the 1-hour half-life temperature of the peroxide initiator can be 90 to 140°C; or it can be 92 to 138°C; the peroxide initiator can specifically include one or more of 2-ethylhexyl carbonate tert-butyl peroxide (117°C), 1,1-di-(tert-butylperoxy)-3,3,5-trimethylcyclohexane (105°C), 2,5-dimethyl-2,5-di-tert-butylhexane (138°C), and benzoyl peroxide (92°C). This invention selects a peroxide initiator, which enables the curing of olefin bond reactions in the system, improves the long-term stability of benzocyclobutene resin in epoxy resin systems, and prevents benzocyclobutene resin from precipitating out during film storage, thus affecting film performance. This invention uses a peroxide with a 1-hour half-life temperature in the range of 90-140°C as an initiator, which can increase the degree of olefin bond reaction between benzocyclobutene resin and alkenyl benzoxazine-containing resin, while not promoting the reaction between alkenyl benzoxazine-containing resin and epoxy resin. This prevents excessive cross-linking during the pre-curing process of the epoxy laminate film, which would affect the chemical etching effect of the epoxy laminate film.

[0032] Based on the mass fraction of the epoxy resin, the epoxy thickening adhesive provided by the present invention comprises 0.3 to 0.6 parts of catalyst, which can be 0.4 to 0.5 parts. In the present invention, the catalyst may include 4-dimethylaminopyridine (DMAP).

[0033] Based on the mass fraction of the epoxy resin, the epoxy layering adhesive provided by this invention comprises 1.5 to 2.6 parts of dispersant, which can be 1.6 to 2.5 parts, further 1.7 to 2.4 parts, and specifically 1.8 parts, 1.9 parts, 2 parts, 2.1 parts, 2.2 parts, or 2.3 parts. In this invention, the dispersant may include one or two of γ-aminopropyltriethoxysilane (KH550), γ-glycidoxypropyltrimethoxysilane (KH560), YB-201A (Changzhou Yabang Yaning), VPS4721 (Evonik), and Dynasylan 4148 (Evonik). While modifying silica with N-phenyl-3-aminopropyltrimethoxysilane can improve the reaction degree between the modified silica filler and the epoxy resin, this method makes it difficult to ensure the stability of the modified silica filler during the etching process, easily leading to poor uniformity of the etched surface. To address the aforementioned shortcomings, this invention employs silica modified with olefin-bonded siloxanes. While ensuring good reactivity, this significantly improves the stability of the modified silica filler in the epoxy layering adhesive system, preventing sedimentation and resulting in a more uniform and controllable surface of the etched epoxy layering film. The epoxy layering adhesive and the epoxy layering film formed by this invention exhibit ultra-low dielectric loss and high copper foil peel strength.

[0034] Based on the mass fraction of the epoxy resin, the epoxy layering adhesive provided by the present invention comprises 3.6 to 5.5 parts of leveling agent, which can be 3.8 to 5.2 parts, or 4 to 5 parts, specifically 3.6, 3.9, 4, 4.1, 4.5, 5.1, or 5.5 parts. In the present invention, the leveling agent may include one or more of BYK-306 (BYK Chemical), BYK-333 (BYK Chemical), BYK-392 (BYK Chemical), BYK-330 (BYK Chemical), BYK-310 (BYK Chemical), and FC4430 (3M Company, USA), specifically one, two, three, four, five, or six types.

[0035] Based on the mass fraction of the epoxy resin, the components of the epoxy layering adhesive provided by the present invention include a solvent. In the present invention, the solvent may include one or more of toluene, cyclopentanone, and cyclohexanone. In the present invention, the amount of solvent used is based on the viscosity of the epoxy layering adhesive being 600~1900 mPa·s. The viscosity of the epoxy layering adhesive may also be 700~1800 mPa·s, further 800~1700 mPa·s, and specifically 900 mPa·s, 1000 mPa·s, 1100 mPa·s, 1200 mPa·s, 1300 mPa·s, 1400 mPa·s, 1500 mPa·s, or 1600 mPa·s.

[0036] The present invention also provides a method for preparing the adhesive for epoxy thickening films described in the above technical solution, comprising the following steps: The alkenyl benzoxazine resin, benzocyclobutene resin, compatibilizer, modified silica and solvent were ball-milled and mixed to obtain a slurry; The slurry is mixed with an initiator and reacted under a protective atmosphere to obtain a reactive slurry; The reaction slurry, epoxy resin, reactive ester curing agent, polyimide resin solution, dispersant and leveling agent are first dispersed and emulsified to obtain the initial adhesive. The initial adhesive is mixed with the catalyst for a second dispersion emulsification, and then mixed with the remaining solvent to obtain an adhesive for epoxy thickening films.

[0037] This invention involves ball milling and mixing an alkenyl benzoxazine resin, a benzocyclobutene resin, a compatibilizer, modified silica, and a solvent to obtain a slurry. In this invention, the mass ratio of the total mass of the alkenyl benzoxazine resin and the benzocyclobutene resin to the mass of the solvent can be 1:0.8~1.5, or 1:1~1.2, specifically 1:1, 1:1.2, or 1:1.5. In this invention, the ball milling speed can be 200~300 r / min, or 220~280 r / min, or further 240~260 r / min, specifically 250 r / min; the ball milling time can be 1.5~2 hours. This invention does not have a specific limitation on the ball-to-material ratio for ball milling; a ball-to-material ratio well-known to those skilled in the art can be used. This invention, by ball milling and mixing the above raw materials, uniformly disperses the modified silica in the resin, preventing silica micro-agglomeration.

[0038] After obtaining the slurry, the present invention mixes the slurry with an initiator and reacts it under a protective atmosphere to obtain a reactive slurry. In the present invention, the reaction temperature can be 90~130℃, or 100~120℃, specifically 110℃; the reaction time can be 5~8h, or 6~7h; the protective atmosphere can include nitrogen, argon, or helium. Under the above conditions, the alkenyl benzoxazine resin and benzocyclobutene resin can crosslink and form a stable slurry dispersion with modified silica.

[0039] After obtaining the reactive slurry, the present invention performs a first dispersion and emulsification on the reactive slurry, epoxy resin, reactive ester curing agent, polyimide resin solution, dispersant, and leveling agent to obtain an initial adhesive. In the present invention, the rotation speed of the first dispersion and emulsification can be 2000~3000 r / min, or 2200~2800 r / min, or further 2400~2600 r / min, or specifically 2500 r / min; the time of the first dispersion and emulsification can be 2~3 h, or 2~2.5 h.

[0040] After obtaining the initial adhesive, the present invention performs a second dispersion and emulsification with the catalyst, and then adds a solvent to adjust the viscosity to obtain an adhesive for epoxy thickening films. In the present invention, the rotation speed of the second dispersion and emulsification can be 2000~3000 r / min, or 2200~2900 r / min, or even 2500~2800 r / min; the time of the second dispersion and emulsification can be 20~30 min, or even 25~30 min.

[0041] After adjusting the viscosity, the present invention may further include filtering the system after adjusting the viscosity to obtain an adhesive for epoxy thickening film. The pore size of the filter membrane can be 5~10μm, 6~9μm, or even 7~8μm.

[0042] The present invention also provides an epoxy thickening composite film, comprising a carrier layer, an epoxy thickening film and a protective layer stacked sequentially; the epoxy thickening film is prepared by the epoxy thickening film adhesive described in the above technical solution or the epoxy thickening film adhesive prepared by the preparation method described in the above technical solution.

[0043] In this invention, the material of the carrier layer may include polyethylene terephthalate (PET); the thickness of the carrier layer may be 38~50μm or 38~45μm.

[0044] In this invention, the thickness of the epoxy thickening film can be 15~110μm, or 20~100μm, specifically 30μm, 40μm, 50μm, 60μm, 70μm, 80μm or 90μm.

[0045] In this invention, the material of the protective layer may include polypropylene; the thickness of the protective layer may be 25~45μm or 30~40μm.

[0046] This invention also provides a method for preparing the epoxy layered composite film described in the above technical solution, comprising the following steps: coating the epoxy layered film with adhesive on the surface of a carrier layer and then drying it to form an epoxy layered adhesive layer on the surface of the carrier layer; pressing a protective layer onto the epoxy layered film to obtain the epoxy layered composite film. In this invention, the drying temperature can be 60~90℃. In this invention, the drying can be carried out in a tunnel oven, and the tunnel oven can be divided into zones one through seven. The temperatures of zones one through seven can be sequentially 60±2℃, 65±2℃, 70±2℃, 75±2℃, 70±2℃, 65±2℃, and 60±2℃, or 60±2℃, 65±2℃, 80±2℃, 85±2℃, 80±2℃, 65±2℃, and 60±2℃, or even 60±2℃. ±1℃, 65±1℃, 70±1℃, 75±1℃, 70±1℃, 65±1℃ and 60±1℃, or 60±1℃, 65±1℃, 80±1℃, 85±1℃, 80±1℃, 65±1℃ and 60±1℃, specifically 60℃, 65℃, 70℃, 75℃, 70℃, 65℃ and 60℃, or 60℃, 65℃, 80℃, 85℃, 80℃, 65℃, 65℃ and 60℃. In this invention, the drying speed can be 4~7 m / min, or 5~6 m / min.

[0047] After obtaining the epoxy thickening adhesive layer, the present invention laminates the protective layer onto the epoxy thickening adhesive film to obtain an epoxy thickening composite film. In the present invention, the lamination temperature can be 90~105℃, or 92~100℃, or even 95±3℃; the lamination pressure can be 1.1~1.3MPa.

[0048] After the lamination is completed, the present invention may further include winding the laminated epoxy composite film. In the present invention, the winding speed may be 4~7 m / min, or 5~6 m / min.

[0049] This invention also provides the application of the epoxy layering adhesive described in the above-mentioned technical solutions, the epoxy layering adhesive prepared by the preparation method described in the above-mentioned technical solutions, the epoxy layering composite film described in the above-mentioned technical solutions, or the epoxy layering composite film prepared by the preparation method described in the above-mentioned technical solutions in chip packaging. The epoxy layering adhesive and the epoxy layering film formed by the present invention have ultra-low dielectric loss and high copper foil peel strength. When the epoxy layering adhesive provided by the present invention is used in chip packaging, during the post-curing process after copper plating and electroplating of the substrate, some of the resin continues to undergo a post-curing reaction under high temperature conditions, further improving the copper foil peel strength. This epoxy layering adhesive and the epoxy layering film and epoxy layering composite film formed by it have excellent application prospects in chip packaging.

[0050] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0051] In this invention, unless otherwise specified, the temperature is room temperature.

[0052] The following examples and comparative examples illustrate the preparation method of modified silica: Alkenyl-containing siloxanes and spherical silica were mixed and modified using a dry method to obtain modified silica. The mass of the alkene-containing siloxane was 1% of the mass of the silica; the modification temperature was 65±5℃, the modification time was 3±0.5 h, and the modification was carried out under stirring conditions.

[0053] Examples 1-6 and Comparative Examples 1-8 Allyl benzoxazine resin, benzocyclobutene resin, compatibilizer, and spherical modified silica were added to a ball mill according to the proportions in Tables 1 to 8. Toluene was added at a ratio of 1:1 between the total mass of allyl benzoxazine resin and benzocyclobutene resin and the mass of solvent. The mixture was ball-milled at 250 r / min for 2 h to obtain a slurry. The slurry was transferred to a heatable reaction vessel with a condenser, an initiator was added, nitrogen gas was introduced, and the mixture was heated under reflux for 6 h. After cooling to room temperature, a reaction slurry was obtained. Epoxy resin, reactive ester curing agent, polyimide resin solution (70% solids content), dispersant, and leveling agent were added and dispersed and emulsified at 2500 rpm for 2 hours to obtain an initial adhesive. The initial adhesive was then dispersed and emulsified with a catalyst at 2800 rpm for 30 minutes. The remaining toluene was added and mixed. The mixture was filtered through a 5-10 μm pore size filter to obtain an adhesive for epoxy laminating films with a viscosity of 600-1500 mPa·s. The reflux reaction temperature in Examples 1-3 and Comparative Examples 1-6 was 100-105°C, and the reflux reaction temperature in Examples 4-6 and Comparative Examples 7-8 was 105-108°C.

[0054] An epoxy laminate film was applied to a PET film (38 μm thick) with adhesive to a predetermined thickness (50 μm). The film was then baked in a tunnel oven (zone seven) to obtain an epoxy laminate film on the PET film surface. A protective layer (polypropylene) was then pressed onto the epoxy laminate film at 95±3℃ and 1.2±0.1 MPa, and finally wound up to obtain an epoxy laminated composite film. In Examples 1-3, 5-6, and Comparative Examples 1-6, the temperatures of the first to seventh zones of the tunnel oven baking process were 60℃, 65℃, 70℃, 75℃, 70℃, 65℃, and 60℃, respectively. In Example 4 and Comparative Examples 7-8, the temperatures of the first to seventh zones of the tunnel oven baking process were 60℃, 65℃, 80℃, 85℃, 80℃, 65℃, 65℃, and 60℃, respectively. The baking and winding speeds were both 5-6 m / min.

[0055] Table 1 Formulation of epoxy film in Example 1

[0056] Table 2 Formulation of epoxy film in Example 2

[0057] Table 3 Formulation of epoxy film in Example 3

[0058] Table 4 Formulation of epoxy film in Example 4

[0059] Table 5 Formulation of epoxy film in Example 5

[0060] Table 6 Formulation of epoxy film in Example 6

[0061] Table 7 Formulations of epoxy films for comparative examples 1-3

[0062] Table 8 Formulations of epoxy films in comparative examples 4-8

[0063] Test Example 1 In the examples and comparative examples, the epoxy laminated composite films prepared by removing the PET film and protective film were pre-cured at 130°C for 30 minutes. Then, the dielectric constant, copper foil peel force, SEM uniformity and etching uniformity of the cured epoxy laminated films were tested. The coefficient of thermal expansion of the epoxy laminated films (without pre-curing) was directly tested. The test results are shown in Table 9.

[0064] The dielectric constant was measured using the SPDR method at a frequency of 10 GHz, and the dielectric constant D was recorded. k Value and dielectric loss tangent D f value.

[0065] SEM Uniformity: Images of the epoxy thickening film cured after chemical etching (Circuposit™ 7800, DuPont) were observed using SEM after gold sputtering, at a magnification of 5000x. SEM images of the epoxy thickening film cured in Examples 1-6 and Comparative Examples 1-3 after chemical etching are shown below. Figures 1-9It can be seen that the epoxy thickening film prepared in the examples was uniformly etched by the chemical solution, while the epoxy thickening films prepared in Comparative Examples 1 and 3 were not etched properly by the chemical solution, and the epoxy thickening film prepared in Comparative Example 2 was over-etched by the chemical solution.

[0066] Test method for copper foil peel strength: The epoxy coating film was etched with chemical solution at 85℃ for 5 minutes, cleaned with deionized water, hung in an oven to dry, and then copper foil layer was formed by copper plating and electroplating. After curing at 200℃ for 90 minutes, the adhesion between the copper foil and the film was tested by peeling at 180 degrees.

[0067] The coefficient of thermal expansion was tested using the TMA method (heating rate of 10℃ / min, air environment, temperature range of 25℃~250℃), using the thin film method, with a test thickness of 50μm and a test sample width of 3±0.1mm; the coefficients of thermal expansion below and above the glass transition temperature were denoted as α1 and α2, respectively.

[0068] The kinematic viscosity of the epoxy laminate film was tested using an Anton Paar rotational rheometer. The heating rate was 5℃ / min, the strain was 5%, and the kinematic viscosity curve was tested at a temperature of 80~180℃. The lowest kinematic viscosity and the temperature point corresponding to the lowest kinematic viscosity were obtained as the kinematic viscosity values ​​of this group, and the unit was foil (P).

[0069] Table 9 Performance test results of the examples and comparative examples

[0070] As shown in Table 9, the curing thermal expansion coefficient α1 of the epoxy laminate film prepared by this invention is 16~20, and the curing thermal expansion coefficient α2 is 37~43; the dielectric properties (10GHz) D k The value is 2.32~2.41, D f The value is 0.00238~0.00267; the copper foil peel strength is 0.46~0.51Kgf / cm; the lowest dynamic viscosity is 1609~2201 foil, and the temperature corresponding to the lowest dynamic viscosity is 119~131℃; the epoxy reinforcing film has good appearance smoothness, no low polarity benzocyclobutene precipitation, and uniform chemical etching.

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An adhesive for epoxy thickening films, characterized in that, The product comprises, by weight parts, the following components: 36-45 parts epoxy resin, 17-25 parts reactive ester curing agent, 10-15 parts alkenyl benzoxazine resin, 5-9 parts benzocyclobutene resin, 7-12 parts polyimide resin, 1.9-2.8 parts compatibilizer, 250-280 parts modified silica, 0.9-1.6 parts peroxide initiator, 0.3-0.6 parts catalyst, 1.5-2.6 parts dispersant, 3.6-5.5 parts leveling agent, and solvent; The epoxy resin includes naphthalene-based epoxy resin; The compatibilizer is a resin containing epoxy groups and olefin bonds; The modified silica is obtained by modifying silica with olefin-containing siloxanes.

2. The adhesive for epoxy thickening films according to claim 1, characterized in that, The active ester curing agent includes one or more of the following: active ester curing agents containing biphenyl structures, active ester curing agents containing polycyclic aromatic hydrocarbon structures, and dicyclopentadiene; the weight-average molecular weight of the active ester curing agent is 1600~4300. The alkenylbenzoxazine-containing resin includes allylbenzoxazine resin and / or vinylbenzoxazine resin; The weight-average molecular weight of the polyimide resin is 20,000 to 55,000.

3. The adhesive for epoxy thickening films according to claim 1, characterized in that, The olefin-containing siloxanes include one or more of vinyltriisopropoxysilane, vinylmethyldiethoxysilane, vinylmethyldimethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, and 3-methacryloyloxypropyltrimethoxysilane; The mass of the olefin-containing siloxane is 0.8-1.1% of the mass of silicon dioxide; The particle size D of the silicon dioxide 50 3~7μm, D 90 It is 8~15μm.

4. The adhesive for epoxy thickening films according to claim 1, characterized in that, The 1-hour half-life temperature of the peroxide initiator is 90~140℃; The catalyst includes 4-dimethylaminopyridine; The solvent includes one or more of toluene, cyclopentanone, and cyclohexanone; The viscosity of the adhesive used for the epoxy laminate film is 600~1900 mPa·s.

5. The method for preparing the adhesive for epoxy thickening films according to any one of claims 1 to 4 comprises the following steps: The alkenyl benzoxazine resin, benzocyclobutene resin, compatibilizer, modified silica and solvent were ball-milled and mixed to obtain a slurry; The slurry is mixed with an initiator and reacted under a protective atmosphere to obtain a reactive slurry; The reaction slurry, epoxy resin, reactive ester curing agent, polyimide resin solution, dispersant and leveling agent are first dispersed and emulsified to obtain the initial adhesive. The initial adhesive is further dispersed and emulsified with the catalyst, and then a solvent is added to adjust the viscosity to obtain an adhesive for epoxy thickening films.

6. The preparation method according to claim 5, characterized in that, The reaction is carried out at a temperature of 90~130℃ for 5~8 hours. The rotation speed of the first dispersion emulsification is 2000~3000 r / min, and the time is 2~3 h; The second dispersion emulsification is carried out at a rotation speed of 2000~3000 r / min for a time of 20~30 min.

7. An epoxy-coated composite film, characterized in that, It comprises a carrier layer, an epoxy thickening film, and a protective layer stacked sequentially; the epoxy thickening film is prepared by the epoxy thickening film adhesive according to any one of claims 1 to 4 or the epoxy thickening film adhesive prepared by the preparation method according to claim 5 or 6.

8. The epoxy-coated composite film according to claim 7, characterized in that, The material of the support layer includes polyethylene terephthalate, and the thickness of the support layer is 38~50μm; The thickness of the epoxy laminate film is 15~110μm; The protective layer is made of polypropylene; the thickness of the protective layer is 25~45μm.

9. The method for preparing the epoxy laminated composite film according to claim 7 or 8, characterized in that, Includes the following steps: After applying an epoxy thickening film to the surface of the carrier layer with adhesive and drying it, an epoxy thickening layer is formed on the surface of the carrier layer. The protective layer is pressed onto the epoxy thickening film to obtain an epoxy thickening composite film.

10. The application of the epoxy thickening adhesive film according to any one of claims 1 to 4, the epoxy thickening adhesive film prepared by the preparation method according to claim 5 or 6, the epoxy thickening composite film according to claim 7 or 8, or the epoxy thickening composite film prepared by the preparation method according to claim 9 in chip packaging.

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