Low-fluidity filling film-state packaging material and preparation method thereof

Abstract

The invention discloses a low-fluidity filling film state packaging material and a preparation method thereof, and a semiconductor packaging substrate and a preparation method thereof. Wherein the encapsulating material includes: a structural resin including at least one selected from the group consisting of a thermoplastic resin, a rubber-based polymer, and a polyimide-based polymer; the adhesive resin comprises a phenolic aldehyde and epoxy system resin material; and an inorganic filler having a surface modified with a specific functional group. Through the unique collaborative design of the bi-component resin and the modified filler, the problem of glue overflow of a liquid packaging material is solved, meanwhile, excellent thermal mechanical performance and strong multi-substrate adhesive force are achieved, the circuit layer adding function is integrated, and the manufacturing process of a high-density substrate is simplified.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor packaging, in particular to a low-flow filling film-state packaging material, a preparation method thereof, a semiconductor packaging substrate and a preparation method thereof. BACKGROUND

[0002] With the rapid development of artificial intelligence (AI), high-performance computing (HPC) and 5G communication technology, semiconductor chips are evolving towards higher operating speed and more functional integration. In order to meet the packaging needs of these high-performance chips, high-density flip chip ball grid array (FCBGA) packaging substrates have become the mainstream technology direction in the industry. In the FCBGA process, after the chip and the substrate are electrically connected, a packaging material is used to fill and protect the precise gap between the chip and the substrate, in order to isolate the environment, enhance mechanical support and provide an effective heat dissipation path.

[0003] At present, one of the technologies widely used in the industry is liquid molding compound (LMC). Its process flow is usually as follows: the liquid resin compound is dispensed or extruded around the chip, and then filled into the entire packaging area under high temperature and high pressure, and finally cured and formed. However, with the continuous improvement of packaging density and chip power, this traditional liquid packaging technology gradually exposes its inherent defects, such as the difficulty of LMC flow to produce flow lines, the easy generation of bubbles or the low yield due to long flow. First, the liquid resin has strong flowability under high temperature and high pressure, which is easy to cause overflow, pollute the gold surface or other functional areas on the substrate, and affect the product yield. Second, the thermal expansion coefficient (CTE) of traditional LMC materials is usually high, and the thermal conductivity coefficient is low, which makes it difficult to meet the heat dissipation needs of AI chips and other high-power devices, and may affect the long-term reliability of the package due to thermal mismatch problems. Finally, traditional LMC is only used as a packaging protection material, and its function is single, which cannot adapt to the development trend of integrating packaging and circuit build-up in future packaging technology.

[0004] Therefore, how to develop a new type of packaging material that can overcome the overflow problem of liquid materials, has excellent thermal mechanical properties (low thermal expansion, high thermal conductivity), and can greatly improve the process rate and yield, has become a technical problem that needs to be solved by technical personnel in the field. SUMMARY

[0005] The main objective of this invention is to propose a low-flowability filled film encapsulation material, which aims to solve the problem of excess adhesive caused by excessive flowability of existing liquid encapsulation materials when applied to high-density encapsulation, while simultaneously improving the thermomechanical properties and functional singularity of the encapsulation material.

[0006] To achieve the above objectives, the present invention proposes a low-flowability filled film encapsulation material comprising a polymer resin and inorganic fillers, wherein,

[0007] The polymer resin includes:

[0008] Structural resin, said structural resin comprising at least one selected from thermoplastic resins, rubber polymers, and polyimide polymers; and

[0009] The adhesive resin comprises phenolic resin and epoxy resin;

[0010] The surface of the inorganic filler is modified with one or more functional groups selected from the group consisting of aniline, alkyl, nitrogen-containing functional groups on the main chain or branches, double-bonded functional groups, and epoxy groups.

[0011] In one embodiment, the thermoplastic resin is selected from at least one of polyvinyl butyral, acrylic resin, toughened epoxy resin, polypropylene resin, and polyolefin resin.

[0012] In one embodiment, the rubber polymer is selected from at least one of natural rubber, nitrile rubber, styrene-butadiene rubber, chloroprene rubber, ethylene propylene diene monomer (EPDM) rubber, modified EPDM rubber, thermoplastic EPDM rubber, acrylic rubber, fluororubber, EPDM rubber, polyurethane rubber, and silicone rubber.

[0013] In one embodiment, the polyimide polymer is selected from at least one of polyimide, poly(p-phenylenebenzodioxazole), polybenzimidazole, and polyimide-modified bismaleimide.

[0014] In one embodiment, the epoxy resin is selected from at least one of glycidylamine epoxy resin, polyfunctional o-cresol glycidyl ether epoxy resin, phenol-biphenyl epoxy resin, bisphenol F solid epoxy resin, isocyanate modified epoxy resin, naphthol epoxy resin, and phenol-formaldehyde epoxy resin.

[0015] In one embodiment, the phenolic resin is selected from at least one of linear phenol-formaldehyde resin and linear BPA-formaldehyde resin.

[0016] In one embodiment, the ratio of phenolic resin content to epoxy resin content in the bonding resin satisfies the following formula:

[0017] Phenolic resin content = (hydroxyl equivalent of phenolic resin / epoxy equivalent of epoxy resin) × epoxy resin content.

[0018] In one embodiment, the bonding resin further includes a flowability adjusting resin selected from at least one of semi-crystalline epoxy resin, liquid bisphenol A type epoxy resin, liquid bisphenol F type epoxy resin, liquid bisphenol A-bisphenol F composite epoxy resin, liquid bisphenol S epoxy resin, liquid phenolic epoxy resin, and liquid phenolic resin.

[0019] In one embodiment, the flowability adjusting resin accounts for no more than 15% by weight of the binding resin.

[0020] In one embodiment, the inorganic filler is selected from at least one of silicon dioxide, aluminum oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium silicate, silicon carbide, titanium carbide, titanium oxide, magnesium oxide, calcium oxide, boron nitride, or aluminum nitride.

[0021] In one embodiment, the encapsulation material comprises, by weight percentage:

[0022] 15% to 95% of the aforementioned polymeric resin composition; and

[0023] The inorganic filler comprises 5% to 85%.

[0024] In one embodiment, the polymeric resin composition comprises, by weight percentage:

[0025] 30% to 97% of the structural resin; and

[0026] 3% to 70% of the adhesive resin.

[0027] In one embodiment, the low-flowability filled film encapsulation material further comprises an additive selected from at least one of leveling agents, dispersants, or defoamers.

[0028] In one embodiment, the low-flowability filled film encapsulation material further comprises a solvent selected from at least one of N-methylpyrrolidone, ethanol, acetone, butanone, cyclohexanone, phthalates, toluene, or xylene.

[0029] The present invention also proposes a method for preparing a low-flowability filled film encapsulation material, used to prepare the low-flowability filled film encapsulation material described in any of the preceding claims, the preparation method comprising the following steps:

[0030] Preparation of resin slurry: The structural resin and the bonding resin are added to a first solvent and mixed to obtain the resin slurry;

[0031] Preparation of filler slurry: The inorganic filler is added to a second solvent and mixed to obtain the filler slurry; and

[0032] Mixing: The filler slurry is slowly added to the stirred resin slurry for mixing to obtain the low-flowability filled film encapsulation material in ink form.

[0033] In one embodiment, in the step of preparing the resin slurry, at least one additive selected from dispersants, defoamers, and leveling agents is pre-added and dissolved in the first solvent; and / or

[0034] In the step of preparing the filler slurry, at least one additive selected from dispersants, defoamers, and leveling agents is pre-added and dissolved in the second solvent.

[0035] In one embodiment, the mixing conditions of the preparation method include at least one of the following:

[0036] The mixing speed during the preparation of the resin slurry is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 60 minutes and 120 minutes.

[0037] The mixing speed during the preparation of the filler slurry is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 60 minutes and 120 minutes; and

[0038] The mixing speed of the filler slurry and the resin slurry is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 60 minutes and 120 minutes.

[0039] In one embodiment, after obtaining the low-flowability filled film encapsulation material in ink form, the preparation method further includes:

[0040] Film formation: The low-flowability filling film encapsulation material in ink form is coated onto a substrate film and then subjected to solvent removal treatment to obtain the low-flowability encapsulation material in dry film form.

[0041] In one embodiment, the conditions for solvent removal treatment include drying for 3 to 10 minutes within a temperature range of 50°C to 120°C.

[0042] This invention also proposes a method for preparing a semiconductor packaging substrate, comprising the following steps:

[0043] Substrate provided: A semiconductor packaging substrate is provided, the substrate having a region to be filled;

[0044] Forming a filling layer: The low-flowability filling film encapsulation material described in the preceding item is applied to the area to be filled on the substrate to form a filling layer;

[0045] Surface pretreatment: The surface of the filler layer is treated to make the filler layer metallizable;

[0046] Metallization process: A metal circuit layer is formed on the surface of the filler layer.

[0047] In one embodiment, when the low-flowability filler film encapsulation material is in ink form, the application method is selected from at least one of dispensing, screen printing, pad printing, and doctor blade coating;

[0048] When the low-flowability filled film encapsulation material is in the form of a dry film, the application method is selected from at least one of vacuum bonding and thermoforming.

[0049] In one embodiment, when the low-flowability filled film encapsulation material is in ink form, the step of forming the filler layer includes:

[0050] Applying ink: Applying the low-flowability filler film encapsulation material in ink form to the area to be filled to form a wet film in the area to be filled;

[0051] Drying: The wet film is dried for 1 to 30 minutes at a temperature range of 30°C to 50°C.

[0052] Curing: Dry the wet film after drying treatment for 30 seconds to 15 minutes within a temperature range of 70℃ to 90℃ to form a dry film;

[0053] Molding: The dry film is molded and cured for 10 minutes to 10 hours in a temperature range of 70°C to 150°C and an environment with a vacuum degree not higher than 0.1MPa, using a molding pressure between 0.1MPa and 12MPa, to form the filling layer.

[0054] In one embodiment, the thickness of the single layer of the wet film is between 148 micrometers and 152 micrometers;

[0055] The thickness of a single dry film is between 118 micrometers and 122 micrometers.

[0056] In one embodiment, the molding step is performed with a release film having a release force of less than 700g;

[0057] After the molding process, the step of forming the filler layer further includes:

[0058] Release film: The release film is peeled off from the surface of the filler layer.

[0059] In one embodiment, the surface pretreatment includes physical polishing or chemical degumming of the filler layer surface, wherein the chemical degumming includes at least one of fluffing treatment, high manganese treatment, and neutralization treatment.

[0060] In one embodiment, after surface pretreatment, the surface roughness coefficient of the filling layer satisfies the following conditions: Ra < 0.2 μm, Rz < 4 μm.

[0061] In one embodiment, after metallization, the peel strength between the filler layer and the copper surface or the surface of the semiconductor substrate is not less than 4.5 N / cm, and the push force with the substrate is not less than 50 MPa.

[0062] In one embodiment, after the metallization process, the preparation method further includes:

[0063] Using the metal circuit layer as a new substrate, the steps of forming a fill layer, the surface pretreatment, and the metallization process are repeated to form at least one additional layer structure on top of the fill layer.

[0064] The present invention also proposes a semiconductor packaging substrate, comprising:

[0065] A substrate body, wherein a region to be filled is provided on the substrate body;

[0066] A filling layer disposed on the area to be filled, and the filling layer being formed by curing a low-flowability filling film encapsulation material as described in any one of claims 1 to 14; and

[0067] A metal circuit layer is disposed on the surface of the filler layer.

[0068] In one embodiment, the semiconductor packaging substrate further includes:

[0069] At least one add-in unit, the add-in unit being disposed above the metal circuit layer, and each add-in unit comprising:

[0070] A second filler layer, the second filler layer being formed by curing a low-flowability filler film encapsulation material as described in any one of claims 1 to 14; and

[0071] The second metal circuit layer is disposed on the surface of the second filler layer.

[0072] The low-flowability filled film encapsulation material provided in this application has at least the following beneficial effects:

[0073] 1. Strong adhesion to multiple substrates: The formulation design of this application ensures excellent adhesion to various substrate surfaces commonly used in semiconductor packaging, including the copper surface of copper foil substrates (especially low-roughness surfaces Ra<0.2µm, Rz<4µm), epoxy green paint surfaces, epoxy fiberglass cloth substrates, M8-M10 substrates, glass, ceramics, and silicon wafers. Its thrust on copper and silicon wafer surfaces is greater than 50MPa, and its peel strength is greater than 4.5N / cm. This high adhesion is mainly achieved through the following mechanisms:

[0074] Core chemical bonding: During the curing process, the epoxy groups of the binder resin (phenolic and epoxy system) in the formulation form strong covalent bonds with the active hydrogens such as hydroxyl groups (-OH) on the substrate surface. At the same time, the phenolic hydroxyl groups of the phenolic resin can form a large number of hydrogen bonds, which together provide strong chemical and physical adsorption forces.

[0075] Synergistic crosslinking effect: Some structural resins (such as polyvinyl butyral containing hydroxyl groups) can also participate in the crosslinking reaction of epoxy / phenolic resins, forming chemical "bridges" that further enhance the cohesive strength and overall adhesion of the entire polymer matrix.

[0076] Interface strength assurance: The inorganic filler, after surface modification, can form a strong chemical bond with the polymer resin matrix, ensuring that there are no weak interfaces inside the material. This allows external stress to be effectively dispersed, preventing damage at the bonding interface between the encapsulation layer and the substrate.

[0077] 2. Superior Thermomechanical Reliability: The encapsulation material of this application exhibits excellent heat resistance, pressure resistance, low coefficient of thermal expansion (CTE), and high thermal conductivity, making it particularly suitable for the encapsulation requirements of high-power devices such as AI. Compared to traditional encapsulation materials, it has a lower CTE (19.86 ppm / ℃ < Tg) and a higher glass transition temperature (Tg = 170℃). This superior thermomechanical performance stems from:

[0078] The skeletal role of high proportion of inorganic fillers: Up to 5% to 85% of the inorganic fillers (such as silica, boron nitride, etc.) in the formulation constitute the rigid skeleton of the material. These fillers themselves have extremely low coefficients of thermal expansion and high thermal conductivity. Their high filling amount effectively suppresses the thermal expansion and contraction of the polymer matrix and provides an efficient pathway for heat transfer.

[0079] A stable network with high cross-linking density: The bonding resin (epoxy and phenolic system) is fully cured through precise stoichiometric proportions, forming a dense and stable three-dimensional cross-linked network. This strong network structure endows the material with excellent structural properties and toughness, ensuring that it can maintain high modulus and structural integrity even at high temperatures.

[0080] Impact resistance of the toughening system: Flexible components such as rubber polymers in the structural resin play a toughening role in the rigid cross-linked network and inorganic filler skeleton, which can effectively absorb and dissipate thermal stress caused by drastic temperature changes and prevent the encapsulation layer from becoming brittle.

[0081] 3. Integrated Packaging and Build-up Design: The cured packaging layer surface supports direct metallization, achieving the integration of packaging and circuit build-up functions. This breaks through the functional limitations of traditional packaging materials. This integration is manifested in:

[0082] Direct metallization is possible: After proper pretreatment (such as degumming or polishing), the surface of the cured encapsulation layer can be chemically plated and electroplated with copper, and the coating has excellent adhesion (peel strength greater than 4.5 N / cm).

[0083] Simplified manufacturing process: By integrating "packaging-curing-layer building up," new circuit layers can be built directly on top of the underlying chip or circuit after packaging and protecting it. This process can be repeated to form a multi-layer structure. This design eliminates the need for additional dielectric layers in traditional processes, greatly simplifying the manufacturing process of high-density interconnect substrates and reducing production costs. Attached Figure Description

[0084] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0085] Figure 1 This is a schematic flowchart of an embodiment of the preparation method of the low-flowability filled film encapsulation material of the present invention;

[0086] Figure 2 This is a schematic flowchart of an embodiment of the method for preparing a semiconductor packaging substrate according to the present invention.

[0087] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0088] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0089] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0090] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0091] This invention proposes a low-flowability filler film encapsulation material for filling and encapsulation in semiconductor packaging substrate manufacturing, particularly suitable for scenarios requiring high-density wiring and high-temperature processes. This encapsulation material aims to solve the technical problems of existing liquid encapsulation materials, such as easy glue overflow, insufficient thermomechanical properties, and limited functionality.

[0092] In this embodiment of the invention, the low-flowability filled film encapsulation material includes a polymer resin and an inorganic filler. The polymer resin provides the composition with basic film-forming properties, adhesion to the substrate, core chemical resistance, and removability in a specific solvent, while the inorganic filler serves as a functional filler that can be used to improve the mechanical properties, scratch resistance, or assist in processing of the composition.

[0093] Specifically, polymeric resins include structural resins and adhesive resins.

[0094] In this composition, the structural resin primarily serves as the main framework, providing film-forming properties, structural integrity, and mechanical toughness for the final encapsulation layer. Unlike liquid materials, the presence of the structural resin allows the encapsulation material to exist in a film state with a defined physical morphology, thus preventing uncontrolled flow when applied to a substrate. Specifically, the structural resin comprises at least one selected from thermoplastic resins, rubber-based polymers, and polyimide polymers.

[0095] Specifically, thermoplastic resins impart fundamental film-forming properties and strength to materials through the physical entanglement of their molecular chains. In some embodiments, the thermoplastic resin may be selected from at least one of polyvinyl butyral, acrylic resin, toughened epoxy resin, polypropylene resin, and polyolefin resin. The core function of using these polymers as structural resins is to leverage their excellent film-forming properties to provide a physical, flexible matrix framework for the encapsulation material. This not only ensures that the material exists in a stable film state before curing, avoiding the problems of liquid material flow and overflow, but also imparts the necessary toughness to the finally cured encapsulation layer to resist thermal shock and mechanical stress.

[0096] Specifically, the structural formula of polyvinyl butyral is:

[0097] The structural formula of acrylic resin is: Furthermore, acrylic resins also include epoxy acrylic resins, the structural formula of which is:

[0098] The structural formula of toughened epoxy resin is:

[0099] The structural formula of polypropylene resin is:

[0100] The structural formula of polyolefin resin is:

[0101] Rubber-based polymers form elastic micro-regions within the material, significantly improving the encapsulation layer's ability to resist thermal shock and mechanical stress, preventing it from becoming brittle under drastic temperature changes.

[0102] In some embodiments, the rubber polymer may be selected from at least one of natural rubber, nitrile rubber, styrene-butadiene rubber, neoprene rubber, ethylene propylene diene monomer (EPDM) rubber, modified EPDM rubber, thermoplastic EPDM rubber, acrylic rubber, fluororubber, EPDM rubber, polyurethane rubber, and silicone rubber. This wide selection of rubber types allows the encapsulation material of the present invention to be precisely selected and compounded according to specific requirements for the toughness, chemical resistance, cost, and temperature resistance of the final encapsulation layer. For example, using high-performance specialty rubbers such as fluororubber or silicone rubber can maximize the high-temperature resistance and chemical resistance of the encapsulation layer, ensuring it can easily withstand the most demanding process conditions. Using general-purpose rubbers such as nitrile rubber and styrene-butadiene rubber provides a more cost-effective solution while meeting basic usage requirements. This diverse selection greatly broadens the applicability and process window of the encapsulation material of the present invention.

[0103] Specifically, the structural formula of natural rubber is:

[0104] The structural formula of nitrile rubber is:

[0105] The structural formula of styrene-butadiene rubber is:

[0106] The structural formula of chloroprene rubber is:

[0107] The structural formulas of binary ethylene propylene rubber, modified ethylene propylene rubber, and thermoplastic ethylene propylene rubber are as follows:

[0108] The structural formula of acrylic rubber is:

[0109] The structural formula of fluororubber is:

[0110] The structural formula of ethylene propylene diene monomer (EPDM) rubber is:

[0111] The structural formula of polyurethane rubber is:

[0112] The structural formula of silicone is:

[0113] In some embodiments, the molecular weight of the structural resin selected is between 5000 g / mol and 200000 g / mol, for example, 5000 g / mol, 100000 g / mol, 200000 g / mol, etc. The purpose of limiting the molecular weight of the structural resin is to ensure that the encapsulation material possesses both excellent film-forming properties and good processability. Specifically, when the molecular weight is not less than 5000 g / mol, the polymer chain length is sufficient to form a stable and flexible film structure through physical entanglement, thereby ensuring the film-forming properties of the material and the toughness of the final encapsulation layer. However, if the molecular weight is higher than 200000 g / mol, it may lead to a decrease in the solubility of the resin in the solvent, resulting in excessively high slurry viscosity, which is not conducive to the subsequent uniform mixing with a high proportion of inorganic fillers and film coating. Therefore, controlling the upper limit of the molecular weight to 200000 g / mol helps to obtain a homogeneous slurry with a wide processing window and easy preparation.

[0114] Polyimide polymers, due to their rigid molecular backbone, offer the best high-temperature resistance and dimensional stability.

[0115] In some embodiments, the polyimide polymer may be selected from at least one of polyimide (PI), poly(p-phenylenebenzodioxazole) (PBO), polybenzimidazole (PBI), and polyimide-modified bismaleimide. These specialty engineering polymers are chosen as structural resins because their molecular backbones are composed of aromatic and heterocyclic units with extremely high chemical bond energy and highly stable structures. This fundamentally endows the encapsulation material with excellent high-temperature resistance, dimensional stability, and superior mechanical strength.

[0116] Specifically, polyimide (PI), poly(p-phenylenebenzodioxazole) (PBO), and polybenzimidazole (PBI) are all high-temperature resistant polymers. Their rigid molecular skeletons ensure that the final encapsulation layer can maintain its structural integrity and physical properties when subjected to harsh high-temperature processes (such as reflow soldering), without thermal degradation or softening.

[0117] Specifically, when polyimide-modified bismaleimide is used as the structural resin, its main function is as a high-performance toughening agent. Bismaleimide (BMI) resin itself has extremely high heat resistance but is relatively brittle. By introducing polyimide (PI) segments for chemical modification, its toughness can be significantly improved while maintaining its high temperature resistance. In the compositions of this invention, this modified resin, as part of the structural resin, can effectively form a skeletal network with both high heat resistance and high toughness in the final encapsulation layer, thereby providing excellent high-temperature stability while significantly enhancing the material's resistance to thermal shock and mechanical cracking.

[0118] Specifically, the structural formula of polyimide is:

[0119]

[0120] The structural formula of poly(p-phenylenebenzodioxazole) is:

[0121] The structural formula of polybenzimidazole is:

[0122] The structural formula of polyamic acid is:

[0123] The main role of the adhesive resin in the composition is to undergo a chemical reaction during the thermosetting stage to form a high-strength three-dimensional cross-linked network, thereby achieving a strong chemical bond between the encapsulation material and the substrate (such as copper surface, green solder mask surface, silicon wafer, etc.).

[0124] Specifically, the adhesive resin comprises resin materials based on a phenolic and epoxy system. Epoxy resin provides excellent adhesion and corrosion resistance, while phenolic resin acts as a curing agent, undergoing a ring-opening polymerization reaction with epoxy resin under heating conditions to form a dense and stable cross-linked structure. This structure endows the cured encapsulation layer with excellent pressure resistance, heat resistance, and chemical resistance.

[0125] It is worth mentioning that the structural resin (e.g., polyvinyl butyral containing hydroxyl groups) in this invention can also undergo cross-linking reactions with thermosetting resins (such as phenolic resins and epoxy resins) and diisocyanates used as adhesive resins. Through appropriate mixing of the structural resin and the adhesive resin, the two resins not only physically blend but also undergo a chemical "bridging reaction" between their molecular chains. This further improves the polymer hardness, modulus, chemical resistance, and coating hardness of the cured encapsulation material, and enhances its adhesion to substrates such as copper. This synergistic cross-linking effect endows the cured encapsulation layer with superior overall performance.

[0126] In some embodiments, the adhesive resin comprises an epoxy resin as the main component and a phenolic resin as the curing agent. The core function of this combination is to form a highly cross-linked, irreversible three-dimensional network structure during the thermosetting stage through ring-opening addition reactions between epoxy groups and phenolic hydroxyl groups. This network structure is fundamental to ensuring the final encapsulation layer achieves high adhesion, high mechanical strength, excellent heat resistance, and chemical resistance.

[0127] Specifically, the epoxy resin material used in this invention has an epoxy molecular weight that can be any value between 2500 g / mol and 6000 g / mol. The epoxy resin is selected from at least one of glycidylamine epoxy resin, polyfunctional o-cresol-aldehyde glycidyl ether type epoxy resin, phenol-biphenyl epoxy resin, bisphenol F solid epoxy resin, isocyanate modified epoxy resin, naphthol type epoxy resin, and phenol-formaldehyde epoxy resin.

[0128] The aforementioned epoxy resins allow for precise control over the final properties of encapsulation materials. For example, using naphthol-based epoxy resins helps improve the glass transition temperature (Tg point) and adhesive properties of the material; using bisphenol F solid epoxy resins can enhance the material's flexibility and corrosion resistance; and using isocyanate-modified epoxy resins can effectively improve the material's bond strength and peel strength.

[0129] Specifically, the structural formula of glycidylamine epoxy resin is: Its epoxy equivalent is between 93 and 150 g / eq, its hydrolytic chlorine content is less than 200 ppm, and its viscosity at 25°C is between 0.5 and 5 Poise.

[0130] The structural formula of the multifunctional o-cresol formaldehyde glycidyl ether epoxy resin is: Its epoxy equivalent ranges from 195 to 230 g / eq, its hydrolytic chlorine at 120℃ ranges from 470 to 1000 g / eq, its ICI viscosity at 150℃ ranges from 0.9 to 60 Poise, and its softening point ranges from 45 to 96℃.

[0131] The structural formula of phenol-biphenyl epoxy resin is: Its epoxy equivalent ranges from 261 to 280 g / eq, hydrolytic chlorine content is less than 100 ppm, viscosity at 25°C is between 0.1 and 4.5 poise, and softening point is 45 to 75°C. Adding it to PVB and its hydroxyl groups in copolymerization can effectively improve the glass strength, Tg, and impact resistance of copper.

[0132] The structural formula of bisphenol F solid epoxy resin is: Its epoxy equivalent ranges from 450 to 1000 g / eq, hydrolytic chlorine content is less than 300 ppm, viscosity at 25°C is <1000 Poise, and softening point is 50–88°C. Solid bisphenol F epoxy resin is characterized by low viscosity and flexibility. The properties of its cured product are almost identical to those of bisphenol A epoxy resin. Adding it to PVB for copolymerization with its hydroxyl groups can effectively improve its corrosion resistance.

[0133] The structural formula of isocyanate (MDI) modified epoxy resin is:

[0134] Its epoxy equivalent ranges from 280 to 380 g / eq, hydrolytic chlorine content is less than 300 ppm, viscosity at 25°C is between 0.5 and 3 Poise, and softening point is 50 to 88°C. Solid bisphenol F epoxy resin is characterized by low viscosity and flexibility. The properties of its cured product are almost identical to those of bisphenol A epoxy resin. Adding it to PVB for copolymerization with its hydroxyl groups can effectively improve bond strength and peel strength.

[0135] The structural formula of naphthol-type epoxy resin is: Its epoxy equivalent ranges from 280 to 380 g / eq, its hydrolytic chlorine content is less than 300 ppm, its viscosity at 25°C is between 0.5 and 3 Poise, and its softening point is between 50 and 88°C. Its curing properties, heat resistance, and mechanical properties are superior to traditional bisphenol A. Furthermore, due to its lower internal stress, it exhibits higher Tg and better adhesive properties. When added to structural resins and copolymerized with their hydroxyl groups, it can effectively improve the Tg point, bond strength, and peel strength.

[0136] The structural formula of phenolic epoxy resin is: Its epoxy equivalent ranges from 165 to 200 g / eq, its hydrolytic chlorine content is less than 250 ppm, its viscosity at 25°C is between 1.1 and 12.5 Poise, and its softening point is 25 to 86°C. Phenolic epoxy resins have two or more epoxy groups in their molecular structure. Therefore, when added to structural resins and copolymerized with their hydroxyl groups, the resulting product has a high crosslinking density and excellent adhesive strength, heat resistance, and chemical resistance. The presence of two or more epoxy groups in the molecular structure leads to a high crosslinking density in the cured product, resulting in excellent adhesive strength, heat resistance, and chemical resistance.

[0137] It is worth mentioning that, in some embodiments, to precisely control the flowability of the encapsulation material at low temperatures and its adhesion to the substrate, the adhesive resin may also include one or more flowability-adjusting resins. These flowability-adjusting resins can be selected from at least one of semi-crystalline epoxy resins, liquid bisphenol A type epoxy resins, liquid bisphenol F type epoxy resins, liquid bisphenol A-bisphenol F composite epoxy resins, liquid bisphenol S epoxy resins, liquid phenolic epoxy resins, and liquid phenolic resins. These resins used for flowability adjustment typically have low epoxy equivalents (between 140 g / eq and 214 g / eq), low hydrolytic chlorine (less than 250 ppm), and low room temperature viscosity (between 1300 mPa·s and 4500 mPa·s at 25°C). Blending them as part of the adhesive resin can effectively improve the overall processability of the composition before coating or pressing, while ensuring high crosslinking density, excellent adhesive strength, heat resistance, and chemical resistance of the cured product.

[0138] Specifically, the structural formula of the semi-crystalline epoxy resin is as follows:

[0139] The structural formulas of liquid bisphenol A type epoxy resin and liquid bisphenol F type epoxy resin are as follows:

[0140]

[0141] The structural formula of liquid bisphenol A-bisphenol F composite epoxy resin is:

[0142] The structural formula of liquid phenolic epoxy resin is:

[0143] The structural formula of liquid phenolic resin is

[0144] In some embodiments, the flowability adjusting resin accounts for no more than 15% by weight of the bonding resin.

[0145] The purpose of limiting the amount of flow-modifying resin described above is to achieve an optimal balance between the material's processing properties and final curing properties. As mentioned earlier, adding an appropriate amount of flow-modifying resin (e.g., liquid epoxy resin or liquid phenolic resin) can effectively reduce the viscosity of the entire composition at low temperatures and improve its processing properties before coating or pressing.

[0146] However, since these flow-adjusting resins typically have lower molecular weights than the solid resins that form the binder, excessive addition (e.g., above 15%) can adversely affect the cured three-dimensional cross-linked network, such as diluting the cross-linking density of the backbone resin. Therefore, controlling their proportion to no more than 15% ensures sufficient material flowability for processing while avoiding the significant decrease in the final product's mechanical strength, heat resistance, or glass transition temperature (Tg point) caused by excessive addition, thus guaranteeing the high reliability of the cured encapsulation layer.

[0147] The phenolic resin is selected from at least one of linear phenol-formaldehyde resin and linear BPA-formaldehyde resin.

[0148] Specifically, the structural formula of linear phenol-formaldehyde resin is: Its free phenol content is <0.6%, softening point is 96-123℃, hydroxyl equivalent is between 105-119 g / eq, and electrical conductivity is less than 8 μS / cm.

[0149] The structural formula of linear BPA formaldehyde resin is: Its free phenol content is 1-45%, softening point is 90-140℃, hydroxyl equivalent is between 112-130 g / eq, and electrical conductivity is less than 20 μS / cm.

[0150] In some embodiments, the ratio of phenolic resin content to epoxy resin content in the bonding resin satisfies the following stoichiometric relationship:

[0151] Phenolic resin content = (hydroxyl equivalent of phenolic resin / epoxy equivalent of epoxy resin) × epoxy resin content.

[0152] The fundamental reason for using the above formula to determine the amount of the two resins is that it follows the stoichiometric principle in chemical reactions, aiming to achieve an ideal balance in the quantity of the two core functional groups participating in the reaction—the phenolic hydroxyl groups (-OH) on the phenolic resin molecular chain and the epoxy groups on the epoxy resin molecular chain—so as to obtain the curing product with the best performance.

[0153] Specifically, the curing process of the adhesive resin mainly involves a ring-opening addition reaction between phenolic hydroxyl groups and epoxy groups, forming a highly cross-linked three-dimensional network structure. Ideally, for this reaction to proceed most completely and efficiently, one phenolic hydroxyl functional group should react with exactly one epoxy functional group. Therefore, the ideal feed ratio should be such that the total molar ratio of phenolic hydroxyl groups to epoxy groups in the formulation is as close to 1:1 as possible.

[0154] Here, "epoxy equivalent weight (EEW)" refers to the number of grams of epoxy resin containing 1 mole of epoxy groups, while "hydroxyl equivalent weight (EEW)" refers to the number of grams of phenolic resin containing 1 mole of phenolic hydroxyl groups. These two values ​​are key parameters for measuring the reactivity of resins. Therefore, the essence of the above formula is a mathematical conversion of the chemical equilibrium relationship of "moles of phenolic hydroxyl groups ≈ moles of epoxy groups". By using this formula, the amount of phenolic resin containing an equal number of reaction sites can be accurately calculated based on the amount of epoxy resin used and its epoxy equivalent weight.

[0155] Using this stoichiometric method to determine the proportions ensures the full progress of the crosslinking reaction, preventing the presence of excessive amounts of any one component that could result in a large number of unreacted functional groups remaining in the cured network. This leads to the highest crosslinking density in the final cured adhesive resin, resulting in superior heat resistance, chemical resistance, and the strongest mechanical strength and adhesion to the substrate.

[0156] Inorganic fillers serve as reinforcing phases, significantly improving the mechanical properties (such as hardness and modulus), heat resistance, and dimensional stability of the encapsulation layer. In this application, the surface of the inorganic filler is modified with specific functional groups selected from one or more of the following groups: aniline groups, nitrogen-containing functional groups on the main chain or branches, double-bonded functional groups, and epoxy groups. The purpose of this surface modification is to improve the interfacial compatibility between the inorganic filler and the organic polymer matrix (structural resin and adhesive resin). These modified functional groups can act as "chemical bridges," chemically bonding or strongly physically interacting with the molecular chains of the resin, thereby firmly "anchoring" the inorganic filler to the polymer matrix, achieving effective stress transfer between the two phases, and maximizing the reinforcing and protective effects of the inorganic filler.

[0157] In some embodiments, the inorganic filler is selected from at least one of silicon dioxide, aluminum oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium silicate, silicon carbide, titanium carbide, titanium oxide, magnesium oxide, calcium oxide, boron nitride, or aluminum nitride.

[0158] Incorporating these inorganic fillers into a high proportion of the polymer resin matrix serves as a reinforcing framework and functional core, significantly improving the overall performance of the cured encapsulation layer. On one hand, these rigid inorganic filler particles form a dense physical support network within the polymer matrix, substantially enhancing the mechanical properties of the composite material, such as hardness, Young's modulus, tensile modulus, and flexural modulus, thereby strengthening its resistance to physical scratches and its ability to maintain its shape under high-temperature and high-pressure processes. On the other hand, by introducing a high content of inorganic fillers with extremely low coefficients of thermal expansion, the overall coefficient of thermal expansion (CTE) of the composite material can be effectively reduced, and its thermal conductivity improved, thus enhancing the heat dissipation efficiency and long-term reliability of the encapsulated device.

[0159] Furthermore, a diverse selection of inorganic fillers is available, allowing for optimization of the encapsulation layer's specific performance based on application requirements during practical operation. For instance, selecting high-hardness fillers such as silicon carbide and aluminum oxide can maximize wear resistance; while selecting high-thermal-conductivity fillers such as boron nitride and aluminum nitride helps to significantly improve the encapsulation layer's heat dissipation capabilities at high temperatures.

[0160] In some embodiments, the encapsulation material comprises 15% to 95% (e.g., 15%, 20%, 25%, 50%, 80%, 95%, etc.) by weight of a polymeric resin composition (i.e., the sum of structural resin and binding resin), and 5% to 85% (e.g., 5%, 10%, 20%, 50%, 60%, 75%, 85%, etc.) of inorganic filler. The macroscopic proportions of the polymeric resin and inorganic filler described above are intended to achieve an optimal balance between the material's encapsulation moldability and functionality.

[0161] Specifically, the polymer resin composition acts as the continuous phase in the formulation, its core role being as a "binder" and "film-forming agent," tightly binding together a large number of inorganic filler particles to form a complete, uniform film with good adhesion to the substrate. When the content of the polymer resin composition is not less than 15%, it is sufficient to completely wet and coat all the filler particles, thereby forming a dense, strong encapsulation layer rather than a loose powder. The inorganic filler, acting as the functional host and reinforcing framework, begins to effectively improve the material's heat resistance, mechanical strength, and reduce the coefficient of thermal expansion when its content is not less than 5%. If the content of inorganic filler is higher than 85% (i.e., the polymer resin content is lower than 15%), the amount of polymer will be insufficient to form a continuous, effective adhesive network, resulting in the material failing to form a dense film layer, and a sharp decrease in mechanical strength and adhesion. Therefore, by controlling the ratio of both within the above range, it is possible to ensure that the encapsulation material possesses both excellent film-forming processability and the superior physical and thermal properties brought about by a high proportion of inorganic filler.

[0162] In some embodiments, the polymeric resin composition comprises 30% to 97% (e.g., 30%, 40%, 50%, 60%, 70%, 80%, 90%, 97%, etc.) of structural resin and 3% to 70% (e.g., 3%, 10%, 20%, 30%, 40%, 50%, 60%, 70%) of binding resin by weight percentage. The aforementioned limitation of the relative proportions of structural resin and binding resin within the polymeric resin system of the encapsulating material aims to achieve a precise balance between the film-forming processability and the cured adhesive properties of the material.

[0163] Specifically, the structural resin is the main component that forms the film-like physical morphology and provides toughness. When its content is not less than 30%, it is sufficient to form a continuous and complete polymer skeleton in the presence of a high proportion of inorganic fillers, ensuring the film-forming properties of the material and the structural integrity of the final encapsulation layer. The binder resin is the key component responsible for chemical cross-linking and adhesion. When its content is not less than 3%, it can effectively form a cross-linked network of sufficient strength during the curing process to achieve a firm adhesion to the substrate. If the binder resin content is higher than 70% (i.e., the structural resin content is lower than 30%), it may weaken the film-forming properties and toughness of the material, increase the shrinkage rate and internal stress during the curing process, which is detrimental to the reliability of the final product. Therefore, by controlling the ratio of the two resins within the above-mentioned range, it is possible to ensure that the encapsulation material of this invention possesses both excellent film-forming toughness and strong cross-linking adhesion.

[0164] In some embodiments, the low-flowability filled film encapsulation material further comprises additives selected from at least one of leveling agents, dispersants, or defoamers. The addition of these additives can optimize the processing performance of the encapsulation material when it is prepared into a liquid slurry, and improve the appearance quality and uniformity of the final cured film.

[0165] Specifically, the dispersant's role is to improve and stabilize the dispersion of high proportions of inorganic fillers in the polymer matrix. Because the encapsulation material of this invention contains a very high amount of inorganic fillers (up to 85%), filler particles are prone to agglomeration. The dispersant can adsorb onto the surface of the inorganic fillers, effectively preventing particle agglomeration through steric hindrance or electrostatic repulsion, thereby reducing the viscosity of the slurry, improving its storage stability, and ensuring uniform filler distribution and consistent performance in the final encapsulation layer.

[0166] The function of leveling agents is to improve the leveling properties of the paste after it is applied to the substrate, so as to form a smooth, defect-free surface. In processes such as screen printing or blade coating, process marks may be left on the surface of the liquid film. Leveling agents can adjust the surface tension of the film, promote its automatic leveling before curing, eliminate these defects, and thus obtain a high-quality film appearance.

[0167] The role of defoamers is to eliminate air bubbles generated during slurry preparation (such as high-speed stirring) and coating processes. If these bubbles remain in the final encapsulation layer, they can form defects such as pinholes and dents, severely affecting the density and functionality of the encapsulation layer. Defoamers effectively disrupt the stability of bubbles, causing them to break down and escape quickly, thereby ensuring a dense, non-porous encapsulation layer.

[0168] In one specific embodiment, examples of additives that may be used include leveling agent BYK530, dispersant BYK2152, and defoamer BYK333.

[0169] In some embodiments, the low-flowability filled film encapsulation material further comprises a solvent selected from at least one of N-methylpyrrolidone, ethanol, acetone, butanone, cyclohexanone, phthalates, toluene, or xylene.

[0170] When preparing the encapsulation material of the present invention into a liquid slurry or ink for coating, the solvent is an essential component. Its main function is to act as a liquid-phase carrier, dissolving or dispersing all solid components in the composition, including structural resins, binding resins, and various additives, and ensuring that a high proportion of inorganic fillers are uniformly suspended therein. Through the action of the solvent, a homogeneous and stable liquid system with suitable viscosity and flowability can ultimately be formed to suit subsequent industrial coating processes.

[0171] Furthermore, the availability of a variety of solvents with different polarities and boiling points endows the composition with excellent process applicability. Those skilled in the art can flexibly formulate single or mixed solvent systems according to the solubility parameters of the specific resin used, as well as the target viscosity and drying rate required for the final slurry, thereby ensuring that the composition of the present invention can be perfectly adapted to various industrial coating processes such as screen printing, blade coating, and spray coating.

[0172] Based on the above embodiments, the low-flowability filled film encapsulation material provided in this application has at least the following beneficial effects:

[0173] 1. Strong adhesion to multiple substrates: The formulation design of this application ensures excellent adhesion to various substrate surfaces commonly used in semiconductor packaging, including the copper surface of copper foil substrates (especially low-roughness surfaces Ra<0.2µm, Rz<4µm), epoxy green paint surfaces, epoxy fiberglass cloth substrates, M8-M10 substrates, glass, ceramics, and silicon wafers. Its thrust on copper and silicon wafer surfaces is greater than 50MPa, and its peel strength is greater than 4.5N / cm. This high adhesion is mainly achieved through the following mechanisms:

[0174] Core chemical bonding: During the curing process, the epoxy groups of the binder resin (phenolic and epoxy system) in the formulation form strong covalent bonds with the active hydrogens such as hydroxyl groups (-OH) on the substrate surface. At the same time, the phenolic hydroxyl groups of the phenolic resin can form a large number of hydrogen bonds, which together provide strong chemical and physical adsorption forces.

[0175] Synergistic crosslinking effect: Some structural resins (such as polyvinyl butyral containing hydroxyl groups) can also participate in the crosslinking reaction of epoxy / phenolic resins, forming chemical "bridges" that further enhance the cohesive strength and overall adhesion of the entire polymer matrix.

[0176] Interface strength assurance: The inorganic filler, after surface modification, can form a strong chemical bond with the polymer resin matrix, ensuring that there are no weak interfaces inside the material. This allows external stress to be effectively dispersed, preventing damage at the bonding interface between the encapsulation layer and the substrate.

[0177] 2. Superior Thermomechanical Reliability: The encapsulation material of this application exhibits excellent heat resistance, pressure resistance, low coefficient of thermal expansion (CTE), and high thermal conductivity, making it particularly suitable for the encapsulation requirements of high-power devices such as AI. Compared to traditional encapsulation materials, it has a lower CTE (19.86 ppm / ℃ < Tg) and a higher glass transition temperature (Tg = 170℃). This superior thermomechanical performance stems from:

[0178] The skeletal role of high proportion of inorganic fillers: Up to 5% to 85% of the inorganic fillers (such as silica, boron nitride, etc.) in the formulation constitute the rigid skeleton of the material. These fillers themselves have extremely low coefficients of thermal expansion and high thermal conductivity. Their high filling amount effectively suppresses the thermal expansion and contraction of the polymer matrix and provides an efficient pathway for heat transfer.

[0179] A stable network with high cross-linking density: The bonding resin (epoxy and phenolic system) is fully cured through precise stoichiometric proportions, forming a dense and stable three-dimensional cross-linked network. This strong network structure endows the material with excellent structural properties and toughness, ensuring that it can maintain high modulus and structural integrity even at high temperatures.

[0180] Impact resistance of the toughening system: Flexible components such as rubber polymers in the structural resin play a toughening role in the rigid cross-linked network and inorganic filler skeleton, which can effectively absorb and dissipate thermal stress caused by drastic temperature changes and prevent the encapsulation layer from becoming brittle.

[0181] 3. Integrated Packaging and Build-up Design: The cured packaging layer surface supports direct metallization, achieving the integration of packaging and circuit build-up functions. This breaks through the functional limitations of traditional packaging materials. This integration is manifested in:

[0182] Direct metallization is possible: After proper pretreatment (such as degumming or polishing), the surface of the cured encapsulation layer can be chemically plated and electroplated with copper, and the coating has excellent adhesion (peel strength greater than 4.5 N / cm).

[0183] Simplified manufacturing process: By integrating "packaging-curing-layer building up," new circuit layers can be built directly on top of the underlying chip or circuit after packaging and protecting it. This process can be repeated to form a multi-layer structure. This design eliminates the need for additional dielectric layers in traditional processes, greatly simplifying the manufacturing process of high-density interconnect substrates and reducing production costs.

[0184] like Figure 1 As shown, the present invention also provides a method for preparing a low-flowability filled film encapsulation material, used in the low-flowability filled film encapsulation material proposed in the present invention. The preparation method includes the following steps:

[0185] S1. Preparation of resin slurry: Structural resin and bonding resin are added to a first solvent and mixed to obtain resin slurry.

[0186] Specifically, this step aims to prepare a homogeneous and stable organic-phase base slurry. Specifically, a structural resin (such as polyvinyl butyral) and a binding resin (such as glycidylamine epoxy resin or linear phenol-formaldehyde resin) are first added to a first solvent. Then, by high-speed shear mixing (e.g., using a homogenizer or high-speed mixer), the two polymers are fully swollen, dissolved, and intertwined in the solvent, ultimately forming a macroscopically homogeneous resin slurry free of gel particles. In a preferred embodiment, to improve the mixing effect in subsequent steps, at least one additive selected from dispersants, defoamers, and leveling agents can be pre-added to the first solvent before adding the resin components. Examples of additives include, but are not limited to, dispersant BYK2152, defoamer BYK530, and leveling agent BYK333. The pre-addition of these additives wets the surface of the resin particles and effectively prevents the resin components from agglomerating and settling in the solvent through electrostatic repulsion or steric hindrance, thereby ensuring the homogeneity and storage stability of the slurry.

[0187] In order to effectively dissolve or disperse the above-mentioned organic components, in some embodiments, the first solvent may be selected from at least one of N-methylpyrrolidone, ethanol, acetone, butanone, cyclohexanone, phthalate, toluene, or xylene.

[0188] Specifically, the mixing process for preparing resin slurry can be achieved using high-speed mixing equipment such as a homogenizer. Of course, the homogenizer can be replaced by an emulsifier, a high-speed mixer, or a collider.

[0189] In some embodiments, the mixing speed for preparing the resin slurry is between 3600 rpm and 7200 rpm. To prevent the resin stability from being affected by heat generated by high-speed shearing, the entire process can be carried out in a reactor with a cooling water jacket to ensure that the slurry temperature does not exceed 45°C. The mixing duration is between 60 minutes and 120 minutes, for example 90 minutes, to ensure the formation of a homogeneous and stable resin slurry (also referred to as slurry A).

[0190] Specifically, limiting the mixing speed to 3600-7200 rpm is to provide sufficient mechanical shear force. This high shear force effectively breaks up polymer agglomerates of the binding and structural resins and accelerates their dissolution and dispersion in the solvent. If the speed is below 3600 rpm, it may result in insufficient mixing, with undissolved gel particles in the slurry, affecting the uniformity of the final film. If the speed is too high, it may damage the polymer molecular chains due to excessive shearing or generate excessive heat.

[0191] Temperature control during mixing, especially maintaining a low temperature below 45°C, is primarily to prevent the solvent from evaporating too quickly due to frictional heat generated by high-speed stirring, thereby ensuring stable and controllable solids content and viscosity of the slurry. Furthermore, maintaining a low temperature also helps avoid any potential and undesirable side reactions, ensuring the chemical stability of the resin slurry before subsequent steps.

[0192] The duration is limited to 60 to 120 minutes to balance efficiency and thoroughness. If the duration is less than 60 minutes, the slurry may be unevenly dispersed, while if it is more than 120 minutes, it will increase energy consumption without any additional benefit. S2, Preparation of filler slurry: Inorganic filler is added to the second solvent and mixed to obtain filler slurry.

[0193] The goal of this step is to prepare a highly dispersed, non-agglomerated inorganic slurry. Specifically, a surface-modified inorganic filler (such as aniline-modified silica) is mixed in a second solvent. The inorganic filler provides mechanical reinforcement, while the surface-modified functional groups improve interfacial compatibility.

[0194] In a preferred embodiment, at least one additive selected from dispersants, defoamers, and leveling agents can be pre-added to the second solvent before adding the inorganic filler to improve the dispersion efficiency of the filler. Examples of additives that can be used include, but are not limited to, dispersant BYK2152, defoamer BYK530, and leveling agent BYK333. This process can use similar equipment and process parameters as step S1, for example, using a homogenizer at a rotation speed of 3600 rpm to 7200 rpm and a temperature not exceeding 45°C, for a duration between 60 minutes and 120 minutes, such as 90 minutes, to ensure that the inorganic filler particles are fully wetted and uniformly dispersed to form a non-agglomerated filler slurry (also referred to as slurry B).

[0195] Specifically, because this invention uses a high proportion of inorganic fillers, these fine powder particles are prone to agglomeration. Therefore, high-speed mixing (3600-7200 rpm) is employed to provide strong mechanical shear energy, breaking down these large agglomerates into smaller, original particles. This allows the solvent and dispersant to fully wet the surface of each particle, resulting in a uniform, fine, and agglomerated suspension. If the speed is too low, the dispersion effect will be poor, leading to defects in the final product.

[0196] During high-speed shearing, controlling the slurry temperature (not exceeding 45℃) is equally crucial. This is not only to prevent solvent evaporation and stabilize the slurry viscosity, but also to ensure that the dispersant can effectively adsorb onto the surface of the filler particles and function stably. Excessively high temperatures may affect the performance of the additives or cause undesirable changes in the slurry properties.

[0197] The duration is limited to 60 to 120 minutes to balance efficiency and thoroughness. A duration shorter than 60 minutes may result in uneven dispersion of the slurry, while a duration longer than 120 minutes increases energy consumption without providing additional benefit. In some embodiments, the second solvent may be selected from at least one of N-methylpyrrolidone, ethanol, acetone, butanone, cyclohexanone, phthalates, toluene, or xylene. S3, Mixing: The filler slurry is slowly added to the stirred resin slurry for mixing to obtain a low-flowability filled film encapsulation material in ink form.

[0198] This step aims to uniformly combine the slurries prepared in the first two steps into a single final product. A "slow addition" method is used to avoid instantaneous thickening or secondary agglomeration due to excessively high local concentrations. After the two slurries are completely combined, thorough shear mixing continues to promote sufficient wetting and interaction between the resin molecular chains and the modified filler surface, ultimately forming a stable system with uniform component distribution and good compatibility.

[0199] In some embodiments, the process parameters for mixing the filler slurry with the resin slurry are a rotation speed of 3600 rpm to 7200 rpm, a temperature not exceeding 45°C, and a duration of 60 minutes to 120 minutes, for example, 90 minutes.

[0200] Specifically, after combining the filler slurry and resin slurry, a sustained high-speed shearing process (3600-7200 rpm) is applied to ensure that the highly dispersed inorganic filler particles are thoroughly and uniformly incorporated into the polymer network composed of the binding resin and toughening resin. This step aims to break up any tiny secondary agglomerations that may occur during mixing and to promote the full wetting and coating of each filler particle surface by the polymer molecular chains, thereby forming a microscopically uniform and synergistic composite system.

[0201] In the final stage after all components have been mixed, low-temperature control (not exceeding 45°C) is particularly important. This is mainly to ensure the chemical stability of the composition and prevent any undesirable or premature chemical reactions between the functional groups on the surface of the binding resin, toughening resin, and modified inorganic filler. By maintaining the temperature below 45°C, the pot life of the mixed slurry can be effectively extended, ensuring that its viscosity, flowability, and other process properties remain stable before coating and film formation.

[0202] The mixing time is extended to 60 to 120 minutes to balance efficiency and thoroughness, while ensuring that the filler particles achieve optimal dispersion in the final resin composition. S4, Film Formation: The low-flowability filler encapsulation material in ink form is coated onto a carrier film (e.g., release film) and then subjected to solvent removal treatment to obtain a low-flowability encapsulation material in dry film form.

[0203] This step is crucial in transforming the ink-like paste into the final solid or semi-solid film product. The paste is uniformly coated onto a carrier film and then heated in a hot air furnace or similar equipment to remove the solvent from the composition.

[0204] In some embodiments, the solvent removal treatment conditions include drying for 3 to 10 minutes in a temperature range of 50°C to 120°C.

[0205] The purpose of imposing the above-mentioned limitations on the process conditions is to achieve an efficient and controllable solvent removal process to form a protective film with stable physical properties that can be used in subsequent processes.

[0206] Specifically, controlling the temperature within this relatively mild range (50℃-120℃) ensures efficient solvent evaporation while avoiding deep chemical cross-linking reactions of the resin components in the composition. If the temperature is below 50℃, solvent evaporation is too slow, resulting in low production efficiency; if the temperature is above 120℃, the adhesive resin may cure prematurely and excessively, which may not only affect the final process performance of the encapsulation material during application but may also lead to film cracking or decreased adhesion due to excessive curing stress.

[0207] Providing a flexible heating time window (3-10 minutes) allows for adaptation to coatings of varying thicknesses and solvent systems with different boiling points. Precise control of heating time and temperature ensures complete solvent removal, resulting in a solvent-free and stable encapsulation film. Correct execution of this step yields encapsulation materials with uniform microstructure; conversely, improper operation (such as excessively high temperature or prolonged time) may lead to agglomeration of inorganic fillers, affecting the performance of the final product.

[0208] Alternatively, the solvent removal process can be performed in a hot air furnace environment. To control the temperature more precisely, the solvent removal process can be carried out with the assistance of a cooling water jacket. This precise temperature control helps to avoid the agglomeration of inorganic fillers caused by local overheating, thereby obtaining a low-flowability filled film encapsulation material with the expected uniform microstructure.

[0209] The present invention also provides a method for preparing a semiconductor packaging substrate, comprising the following steps:

[0210] S10. Provide substrate: Provide a semiconductor packaging substrate, the substrate having a region to be filled.

[0211] Specifically, this could be an FCBGA substrate or a high-frequency copper-clad laminate substrate. This substrate has areas that need to be filled for protection or added layers, such as structural gaps between the chip and other components, or cavities requiring functional protection.

[0212] S20. Forming a filling layer: The low-flowability filling film encapsulation material described in any of the foregoing embodiments is applied to the area to be filled on the substrate to form a filling layer.

[0213] Specifically, the application method can vary depending on the form of the encapsulation material. When the encapsulation material is in ink form, it can be applied to the area to be filled using methods such as screen printing, stencil printing, pad printing, doctor blade coating, or dispensing. When the encapsulation material is in dry film form, it can be laminated onto the area to be filled using methods such as vacuum lamination or thermoforming. Among these methods, dry film encapsulation materials are more suitable for addressing issues such as flow lines, bubbles, or low yield due to high-density bumps or circuits between the chip and the substrate in LMC (Liquid Molding Compound) materials.

[0214] In some embodiments, when the low-flowability filler film encapsulation material is in ink form, the step of forming the filler layer (S20) can be further refined into a multi-stage process to achieve precise control over the morphology of the filler layer and the curing process. This process may include:

[0215] S21. Applying ink: Applying a low-flowability filling film encapsulation material in ink form to the area to be filled on the substrate by means of dispensing, screen printing, pad printing or doctor blade coating, so as to form a wet film with a specific thickness in the area to be filled.

[0216] S22. Drying: The wet film is dried for 1 to 30 minutes at a temperature range of 30°C to 50°C. The purpose of this step is to remove most of the low-boiling-point solvents in the ink through a relatively gentle heating process, so that the wet film can be initially set and bubbles or surface defects caused by excessively rapid heating can be avoided.

[0217] S23. Curing: Subsequently, the wet film, after drying treatment, is dried for 30 seconds to 15 minutes at a temperature range of 70°C to 90°C to form a dry film. This step aims to remove residual high-boiling-point solvents and induce a preliminary cross-linking reaction in the material (i.e., entering the B-stage state), thereby transforming the liquid wet film into a semi-cured dry film with a fixed shape and non-stick surface. S24. Molding: Finally, the dry film is molded for 10 minutes to 10 hours at a temperature range of 70°C to 150°C, in an environment with a vacuum degree not exceeding 0.1 MPa, using a molding pressure between 0.1 MPa and 15 MPa, to form the final, fully cured filler layer. In this step, the vacuum environment helps to eliminate any possible residual volatiles or air, ensuring the filler layer is dense and non-porous; while the combined effect of heat and pressure promotes a complete cross-linking reaction of the binder resin, giving the filler layer final mechanical strength and thermal stability. To prevent the cured filler layer from sticking to the mold, the molding step can be performed with a release film having a release force of less than 700g. Since this molding process operates on a pre-formed dry film, rather than a highly fluid liquid, excessive material flow can be effectively avoided, ensuring that the amount of excess adhesive is less than 0.1mm.

[0218] It is worth noting that, as an alternative implementation method, in some embodiments of this application, the wet film may be molded first and then cured.

[0219] In some embodiments, the molding step can be performed with a release film having a release force of less than 700g. Specifically, a release film can be placed on the back side of the dry film (the side facing away from the object to be bonded). In this case, the step of forming the filler layer also includes a film peeling step.

[0220] S25. Removing the film: After the molding process, the release film is removed from the surface of the filler layer to expose a smooth and clean filler layer surface.

[0221] S30. Surface pretreatment: Treat the surface of the cured filler layer to make it metallizable.

[0222] This treatment can greatly enhance the adhesion between the subsequent metal circuit layer and the filler layer. In some embodiments, the surface pretreatment can be selected from physical polishing or chemical desmearing, which typically includes steps such as fluffing, potassium permanganate oxidation and neutralization.

[0223] In some embodiments, after surface pretreatment, the surface roughness coefficient of the filling layer may satisfy the following conditions: Ra < 0.2 μm and Rz < 4 μm.

[0224] The core purpose of precisely controlling the surface roughness of the filler layer is to create an optimal bonding interface for subsequent metallization processes (especially electroless copper plating and electroplating) to achieve excellent copper adhesion.

[0225] Specifically, Ra and Rz are key parameters characterizing the arithmetic mean deviation of the surface profile and the height of micro-irregularities. Controlling the surface roughness within this specific microscopic range is not about achieving absolute smoothness, but rather about forming a microscopic "teething" or "anchoring" structure on the filler layer surface. This structure significantly increases the effective contact area and physical bonding between the filler layer and the subsequently deposited metal seed layer (such as electroless copper plating), thus providing strong adhesion for the final metal circuit layer. If the surface is too smooth, the mechanical bonding force is insufficient, leading to easy peeling of the metal layer; if the surface is too rough, it may affect the signal integrity of high-frequency circuits. Therefore, Ra < 0.2 μm and Rz < 4 μm represent an optimized result that balances high adhesion with excellent high-frequency electrical performance.

[0226] S40, Metallization: A metal circuit layer is formed on the surface of the filler layer.

[0227] This step aims to form a conductive metal circuit layer on the pretreated filler layer surface. In some embodiments, this step typically involves first performing chemical plating (e.g., electroless copper plating) to deposit a thin, conductive metal seed layer on the filler layer surface, followed by electroplating (e.g., copper plating) to thicken the metal layer to the desired circuit thickness. After the metal layer deposition is complete, it can also be subjected to conventional patterning processes (such as photolithography) to form a predetermined precision circuit pattern.

[0228] In some embodiments, after metallization, the peel strength between the filler layer and the copper surface or semiconductor substrate is not less than 4.5 N / cm, and the push force with the substrate is not less than 50 MPa. These two parameters are key technical indicators for evaluating the performance of the filler layer as a build-up medium; they together quantify the bonding strength between the newly formed metal circuit layer and the underlying filler layer. Achieving such high bonding strength enables the packaging material of this invention to achieve the function of "integrated packaging and build-up".

[0229] Specifically, peel strength measures the force required to peel the formed metal circuit strip from the surface of the filler layer. A peel strength of not less than 4.5 N / cm ensures that the metal circuitry will not peel or delaminate during subsequent soldering, assembly, and temperature cycling during long-term use, thus guaranteeing the integrity and reliability of the circuit.

[0230] The thrust measures the lateral stress required to vertically pull the metal layer away from the filler layer surface. A thrust of at least 50 MPa demonstrates a very strong interfacial bond between the metal layer and the filler layer, which is crucial for ensuring that critical structures such as pads and vias do not detach when subjected to mechanical or thermal stress.

[0231] It is understood that through the unique material formulation design and optimized surface pretreatment process of this invention, the cured filler layer can provide an ideal bonding interface for subsequent metallization, thereby achieving a high adhesion that surpasses conventional encapsulation materials, fully meeting the stringent requirements of a high-performance add-on medium.

[0232] In some embodiments, to ensure that the final filled layer has a uniform and controllable thickness, the thicknesses of the wet film and the dry film can be precisely controlled. Specifically, after the ink application step, the thickness of the wet film can be controlled between 148 micrometers and 152 micrometers (i.e., 150 μm ± 2 μm); after the drying and film-forming steps, the thickness of the dry film can be between 118 micrometers and 122 micrometers (i.e., 120 μm ± 2 μm) to 240 μm ± 2 μm, wherein the 240 μm ± 2 μm dry film thickness is obtained by stacking two wet films. Of course, by controlling the thickness of the wet film, a 240 μm ± 2 μm dry film can also be formed in one step.

[0233] The purpose of limiting the thickness of these two intermediate stages is to precisely control the volume and shape of the final filling layer in order to perfectly adapt to the packaging requirements of different depths.

[0234] First, the wet film thickness is limited to the range of 150μm±2μm for the following reasons:

[0235] Ensure sufficient material quantity: The wet film is the initial coating containing solvent. Setting it to 150 μm ensures that after the solvent is removed in the subsequent drying and film-forming steps, the remaining solid components (i.e., resin and filler) can form a dry film with sufficient volume and thickness to completely fill the structural voids on the semiconductor substrate.

[0236] Process window optimization: This thickness is an optimized value for common industrial coating processes such as screen printing and blade coating. It ensures the uniformity and stability of the coating while avoiding defects such as difficult solvent removal and easy bubble formation caused by excessive coating thickness.

[0237] Secondly, limiting the dry film thickness to the range of 120μm±2μm to 240μm±2μm is based on the following considerations:

[0238] Standard cell thickness (120μm): 120μm is the standard dry film thickness formed after a single 150μm wet film coating and solvent removal treatment. This thickness is sufficient to meet the gap filling requirements of many conventional packaging applications.

[0239] Modular Thickening Capability (240μm): For complex packaging structures with higher elevation differences or deeper cavities, this invention provides a modular thickening solution. As shown in the embodiments in the technical disclosure, a total thickness of 240μm can be achieved by stacking two 120μm dry films. This approach greatly enhances process flexibility, allowing the same packaging material to be adapted to different packaging requirements through simple process adjustments, without the need to develop ink formulations with different solid content.

[0240] In some embodiments, after metallization, the method for fabricating the semiconductor packaging substrate of this application may further include one or more repeated layer-addition steps. Specifically, the method includes: using the metal circuit layer formed in step S40 as a new substrate, repeatedly performing the steps of forming a fill layer (S20), surface pretreatment (S30), and metallization (S40) to form at least one additional layer-addition structure on top of the first fill layer.

[0241] This repeated layering step utilizes the dual function of the low-flowability filler film encapsulation material of this invention, which serves as both an encapsulation protection material and a high-performance layering medium. Each repetition of this cycle adds a new insulating layer (i.e., a filler layer) and a new wiring layer (i.e., a metal circuit layer) on top of the previous circuit layer, thereby constructing a multilayer high-density interconnect (HDI) structure that meets the complex chip wiring requirements, or even a more refined UHDI structure.

[0242] Understandably, this method allows manufacturers to use the same material to simultaneously encapsulate and protect the underlying components and build the upper-layer circuitry. This significantly simplifies the complex processes required for traditional high-density substrate manufacturing, reduces the types of materials used, and thus effectively lowers production costs and improves manufacturing efficiency.

[0243] This application also provides a semiconductor packaging substrate, comprising:

[0244] A substrate body, on which a region to be filled is provided;

[0245] A filler layer, disposed on the area to be filled, wherein the filler layer is formed by curing the low-flowability filler film encapsulation material of any of the preceding embodiments; and

[0246] A metal circuit layer is disposed on the surface of the fill layer.

[0247] In some embodiments, in order to construct a multilayer high-density interconnect (HDI) structure that meets the requirements of complex chip wiring, the semiconductor packaging substrate may further include at least one layer addition unit disposed on the metal circuit layer.

[0248] Specifically, each add-in unit includes a second filler layer and a second metal circuit layer. The second filler layer is also formed by curing the low-flowability filler film encapsulation material described in any of the preceding claims, and it directly covers the first metal circuit layer, serving as insulation and support. The second metal circuit layer is disposed on the surface of the second filler layer.

[0249] This build-up structure is formed by repeatedly performing the steps of the semiconductor packaging substrate fabrication method of the present invention. After the first metal circuit layer is formed and patterned, it is used as a new substrate to repeat the steps of forming a fill layer, surface pretreatment, and metallization to obtain a build-up unit. To achieve electrical interconnection between different metal circuit layers, before forming the second metal circuit layer, a step may be included to create vias penetrating to the first metal circuit layer in the second fill layer using laser or mechanical drilling. In the subsequent metallization process, the walls of these vias are metallized together with the surface of the second fill layer, thereby forming interlayer conductive paths. This build-up process can be repeated multiple times according to design requirements to construct complex circuit substrates with any desired number of layers.

[0250] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A low-flowability filled film encapsulation material, characterized in that, Including polymer resins and inorganic fillers, among which, The polymer resin includes: Structural resin, said structural resin comprising at least one selected from thermoplastic resins, rubber polymers, and polyimide polymers; and The adhesive resin comprises phenolic resin and epoxy resin; The surface of the inorganic filler is modified with one or more functional groups selected from the group consisting of aniline, alkyl, nitrogen-containing functional groups on the main chain or branches, double-bonded functional groups, and epoxy groups.

2. The low-flowability filled film encapsulation material as described in claim 1, characterized in that, The thermoplastic resin is selected from at least one of polyvinyl butyral, acrylic resin, toughened epoxy resin, polypropylene resin, and polyolefin resin.

3. The low-flowability filled film encapsulation material as described in claim 1, characterized in that, The rubber polymer is selected from at least one of natural rubber, nitrile rubber, styrene-butadiene rubber, chloroprene rubber, ethylene propylene diene monomer (EPDM) rubber, modified EPDM rubber, thermoplastic EPDM rubber, acrylic rubber, fluororubber, EPDM rubber, polyurethane rubber, and silicone rubber.

4. The low-flowability filled film encapsulation material as described in claim 1, characterized in that, The polyimide polymer is selected from at least one of polyimide, poly(p-phenylenebenzodioxazole), polybenzimidazole, and polyimide-modified bismaleimide.

5. The low-flowability filled film encapsulation material as described in claim 1, characterized in that, The epoxy resin is selected from at least one of glycidylamine epoxy resin, polyfunctional o-cresol glycidyl ether epoxy resin, phenol-biphenyl epoxy resin, bisphenol F solid epoxy resin, isocyanate modified epoxy resin, naphthol epoxy resin, and phenol-formaldehyde epoxy resin.

6. The low-flowability filled film encapsulation material as described in claim 1, characterized in that, The phenolic resin is selected from at least one of linear phenol-formaldehyde resin and linear BPA-formaldehyde resin.

7. The low-flowability filled film encapsulation material as described in claim 1, characterized in that, In the bonding resin, the ratio of phenolic resin content to epoxy resin content satisfies the following formula: Phenolic resin content = (hydroxyl equivalent of phenolic resin / epoxy equivalent of epoxy resin) × epoxy resin content.

8. The low-flowability filled film encapsulation material as described in claim 1, characterized in that, The bonding resin further includes a flowability adjusting resin, which is selected from at least one of semi-crystalline epoxy resin, liquid bisphenol A type epoxy resin, liquid bisphenol F type epoxy resin, liquid bisphenol A-bisphenol F composite epoxy resin, liquid bisphenol S epoxy resin, liquid phenolic epoxy resin, and liquid phenolic resin.

9. The low-flowability filled film encapsulation material as described in claim 8, characterized in that, The flowability adjusting resin accounts for no more than 15% of the weight percentage of the bonding resin.

10. The low-flowability filled film encapsulation material as described in claim 1, characterized in that, The inorganic filler is selected from at least one of silicon dioxide, aluminum oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium silicate, silicon carbide, titanium carbide, titanium oxide, magnesium oxide, calcium oxide, boron nitride, or aluminum nitride.

11. The low-flow encapsulation material according to any one of claims 1 to 10, characterized in that, The encapsulation material comprises, by weight percentage: 15% to 95% of the aforementioned polymeric resin composition; and The inorganic filler comprises 5% to 85%.

12. The low-flow encapsulation material as described in claim 10, characterized in that, The polymeric resin composition comprises, by weight percentage: 30% to 97% of the structural resin; and 3% to 70% of the adhesive resin.

13. The low-flowability filled film encapsulation material as described in claim 1, characterized in that, The low-flowability filled film encapsulation material further includes an additive selected from at least one of leveling agents, dispersants, or defoamers.

14. The low-flowability filled film encapsulation material as described in claim 1, characterized in that, The low-flowability filled film encapsulation material further comprises a solvent selected from at least one of N-methylpyrrolidone, ethanol, acetone, butanone, cyclohexanone, phthalates, toluene, or xylene.

15. A method for preparing a low-flowability filled film encapsulation material, used to prepare the low-flowability filled film encapsulation material according to any one of claims 1 to 14, characterized in that, The preparation method includes the following steps: Preparation of resin slurry: The structural resin and the bonding resin are added to a first solvent and mixed to obtain the resin slurry; Preparation of filler slurry: The inorganic filler is added to a second solvent and mixed to obtain the filler slurry; and Mixing: The filler slurry is slowly added to the stirred resin slurry for mixing to obtain the low-flowability filled film encapsulation material in ink form.

16. The method for preparing the low-flowability filled film encapsulation material as described in claim 15, characterized in that, In the step of preparing the resin slurry, at least one additive selected from dispersants, defoamers, and leveling agents is pre-added and dissolved in the first solvent; and / or In the step of preparing the filler slurry, at least one additive selected from dispersants, defoamers and leveling agents is pre-added and dissolved in the second solvent.

17. The method for preparing the low-flowability filled film encapsulation material as described in claim 15, characterized in that, The mixing conditions of the preparation method include at least one of the following: The mixing speed during the preparation of the resin slurry is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 60 minutes and 120 minutes. The mixing speed during the preparation of the filler slurry is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 60 minutes and 120 minutes; and The mixing speed of the filler slurry and the resin slurry is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 60 minutes and 120 minutes.

18. The method for preparing the low-flowability filled film encapsulation material according to any one of claims 15 to 17, characterized in that, After obtaining the low-flowability filled film encapsulation material in ink form, the preparation method further includes: Film formation: The low-flowability filled film encapsulation material in ink form is coated onto a carrier film and then subjected to solvent removal treatment to obtain the low-flowability encapsulation material in dry film form.

19. The method for preparing the low-flowability filled film encapsulation material as described in claim 18, characterized in that, The conditions for solvent removal treatment include drying for 3 to 10 minutes within a temperature range of 50°C to 120°C.

20. A method for preparing a semiconductor packaging substrate, characterized in that, Includes the following steps: Substrate provided: A semiconductor packaging substrate is provided, the substrate having a region to be filled; Forming a filling layer: The low-flowability filling film encapsulation material according to any one of claims 1 to 14 is applied to the area to be filled on the substrate to form a filling layer; Surface pretreatment: The surface of the filler layer is treated to make the filler layer metallizable; Metallization process: A metal circuit layer is formed on the surface of the filler layer.

21. The method for preparing a semiconductor packaging substrate as described in claim 20, characterized in that, When the low-flowability filler film encapsulation material is in ink form, the application method is selected from at least one of dispensing, screen printing, pad printing, and doctor blade coating; When the low-flowability filled film encapsulation material is in the form of a dry film, the application method is selected from at least one of vacuum bonding and thermoforming.

22. The method for preparing a semiconductor packaging substrate as described in claim 20, characterized in that, When the low-flowability filler film encapsulation material is in ink form, the step of forming the filler layer includes: Applying ink: Applying the low-flowability filler film encapsulation material in ink form to the area to be filled to form a wet film in the area to be filled; Drying: The wet film is dried for 1 to 30 minutes at a temperature range of 30°C to 50°C. Curing: Dry the wet film after drying treatment for 30 seconds to 15 minutes within a temperature range of 70℃ to 90℃ to form a dry film; Molding: The dry film is molded and cured for 10 minutes to 10 hours in a temperature range of 70°C to 150°C, in an environment with a vacuum degree not higher than 0.1MPa, and with a molding pressure between 0.1MPa and 12MPa, to form the filling layer.

23. The method for preparing a semiconductor packaging substrate as described in claim 22, characterized in that, The thickness of a single wet film is between 148 micrometers and 152 micrometers; The thickness of a single dry film is between 118 micrometers and 122 micrometers.

24. The method for preparing a semiconductor packaging substrate as described in claim 22, characterized in that, The molding step is performed using a release film with a release force of less than 700g; After the molding process, the step of forming the filler layer further includes: Release film: The release film is peeled off from the surface of the filler layer.

25. The method for preparing a semiconductor packaging substrate as described in claim 20 is characterized in that, The surface pretreatment includes physical polishing or chemical degumming of the filler layer surface, wherein the chemical degumming includes at least one of fluffing treatment, high manganese treatment, and neutralization treatment.

26. The method for preparing a semiconductor packaging substrate as described in claim 20, characterized in that, After surface pretreatment, the surface roughness coefficient of the filling layer satisfies the following conditions: Ra < 0.2 μm, Rz < 4 μm.

27. The method for preparing the semiconductor packaging substrate as described in claim 20, characterized in that, After metallization, the peel strength between the filler layer and the copper surface or the surface of the semiconductor substrate is not less than 4.5 N / cm, and the thrust with the substrate is not less than 50 MPa.

28. The method for preparing a semiconductor packaging substrate according to any one of claims 20 to 27, characterized in that, Following the metallization process, the preparation method further includes: Using the metal circuit layer as a new substrate, the steps of forming a fill layer, the surface pretreatment, and the metallization process are repeated to form at least one additional layer structure on top of the fill layer.

29. A semiconductor packaging substrate, characterized in that, include: A substrate body, wherein a region to be filled is provided on the substrate body; A filling layer is disposed on the area to be filled, and the filling layer is formed by curing a low-flowability filling film encapsulation material as described in any one of claims 1 to 14; as well as A metal circuit layer is disposed on the surface of the filler layer.

30. The semiconductor packaging substrate as claimed in claim 29, characterized in that, The semiconductor packaging substrate further includes: At least one add-in unit, the add-in unit being disposed above the metal circuit layer, and each add-in unit comprising: A second filler layer, the second filler layer being formed by curing a low-flowability filler film encapsulation material as described in any one of claims 1 to 14; and The second metal circuit layer is disposed on the surface of the second filler layer.

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