Tip-scale filter package film, filter tip, and method for preparing the same

Abstract

The present invention provides a chip scale filter package film, a filter tip, and a method for preparing the same. The package film contains, by mass%, 55-70% silica, 14-24% epoxy resin, 15-20% phenoxy resin, 1-2.5% curing agent, 0.5-1.2% accelerator, and 0.3-0.9% colorant. The epoxy resin consists of polyurethane-modified bisphenol A type epoxy resin and a tetrafunctional epoxy resin, and the molecular weight of the phenoxy resin is 50,000-150,000. The present invention selects to combine large-particle silica, high molecular weight phenoxy resin, polyurethane-modified bisphenol A type epoxy resin, and tetrafunctional epoxy resin to ensure that the package film has a certain fluidity under vacuum hot-press conditions, covering the periphery of the filter tip and guaranteeing that gum does not penetrate the cavity functional area. Furthermore, the package film can reduce the package size of the filter, simplify the filter packaging method, lower packaging costs, improve packaging efficiency and yield, and better meet future miniaturization packaging needs.

Description

Technical Field

[0001] The present invention belongs to the technical field of filter packages, and particularly relates to a chip scale filter package film, a filter chip, and a preparation method thereof.

Background Art

[0002] With the rapid development of communication devices, the requirements for filter package technology are also increasing. A filter is an important semiconductor device, and filter packaging is a process of sealing the filter functional area to form a cavity so that the filter is not affected by the external environment.

[0003] Filter components are small in size and high in packaging process cost. For example, by providing a blocking member to form a sealed cavity around the functional surface of the filter chip to prevent the entry of molding materials, or using a method of parallel welding with a ceramic case, the functional surface of the filter is adhered into a deep cavity formed in the case, and then the air is replaced with nitrogen to ensure that the device is not contaminated. However, in such a packaging method, the size is large and the processing efficiency is low, or a method of coating a film is used to isolate the external molding material to ensure that a cavity is formed so that the functional area of the filter is not contaminated. This requires that the coated film has excellent flexibility and adhesion, and also increases the packaging size of the filter.

[0004] Currently, the packaging method for miniaturizing filters involves flip-chip bonding the filter's bare chip to a substrate via a metal sphere, then covering the top surface of the filter's bare chip with molding material to seal the filter's bare chip inside the molding gum, and finally curing the molding gum to cut into individual molded filter products. Due to the high fluidity of the molding material, commercially available molding materials tend to penetrate into the inside of the device during the molding process, contaminating the functional area and cavity environment of the filter, affecting the normal operation of the device, and ultimately reducing the filter production yield.

[0005] Therefore, how to provide a chip-scale filter package film that controls the fluidity of the chip-scale filter package film to prevent contamination of the functional area of ​​the filter chip and further improve the production efficiency of the filter chip is a technical problem that those skilled in the art must urgently solve. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide a chip-scale filter package film, a filter tip, and a method for preparing the same, in order to solve at least the above technical problems. [Means for solving the problem]

[0007] In a first aspect of the present invention, in order to achieve the above objective, a chip scale filter package film is provided, the chip scale filter package film comprising, by mass%, 55% to 70% silica, 14% to 24% epoxy resin, 15% to 20% phenoxy resin, 1% to 2.5% curing agent, 0.5% to 1.2% accelerator, and 0.3% to 0.9% coloring agent, wherein the epoxy resin consists of polyurethane-modified bisphenol A type epoxy resin and a tetrafunctional epoxy resin, and the molecular weight of the phenoxy resin is 50,000 to 150,000.

[0008] In the first embodiment, the particle size D50 of the silica is 7 to 10 μm.

[0009] In the first embodiment, the epoxy equivalent of the polyurethane-modified bisphenol A type epoxy resin is 230 to 260 g / eq, and the epoxy equivalent of the tetrafunctional epoxy resin is 95 to 125 g / eq.

[0010] In the first embodiment, the epoxy resin comprises at least one of tetraglycidyl-1,3-bisaminomethylcyclohexane, tetraglycidyldiaminodiphenylmethane, and tetraglycidylxylenediamine.

[0011] In the first embodiment, the curing agent is a latent curing agent containing dicyandiamide.

[0012] In the first embodiment, the accelerator is a latent accelerator containing an imidazole compound.

[0013] In the first embodiment, the colorant includes carbon black having an average particle size of 5 nm.

[0014] A second aspect of the present invention provides a method for preparing a chip-scale filter package film as described in the first aspect, wherein the preparation method is as follows: The first step is to stir-mix each component according to their respective mass percentages to obtain a first slurry, wherein the mass percentages of each component are, specifically, that the chip scale filter package film contains, by mass%, 55% to 70% silica, 14% to 24% epoxy resin, 15% to 20% phenoxy resin, 1% to 2.5% curing agent, 0.5% to 1.2% accelerator, and 0.3% to 0.9% coloring agent, and the epoxy resin consists of polyurethane-modified bisphenol A type epoxy resin and tetrafunctional epoxy resin, and the molecular weight of the phenoxy resin is 50,000 to 150,000. S2 involves transferring the first slurry to a bead mill and performing a dispersion process to obtain a uniformly dispersed second slurry. S3 involves vacuum degassing the second slurry to obtain a third slurry, The third slurry is applied to the base film and dried (S4), The process includes S5, which involves removing the base film after drying is complete to obtain a chip scale filter package film.

[0015] A third aspect of the present invention provides a method for preparing a filter tip, the preparation method comprising the steps of stirring and mixing, bead milling and vacuum degassing each component of the tip scale filter package membrane described in the first aspect to obtain a mixed slurry, wherein the mass percentage of each component is, specifically, that the tip scale filter package membrane contains, by mass, 55% to 70% silica, 14% to 24% epoxy resin, 15% to 20% phenoxy resin, 1% to 2.5% curing agent, 0.5% to 1.2% accelerator and 0.3% to 0.9% coloring agent, the epoxy resin consists of polyurethane-modified bisphenol A type epoxy resin and tetrafunctional epoxy resin, and the molecular weight of the phenoxy resin is 50,000 to 150,000. The process includes the steps of: applying the mixed slurry to a base film and drying it to obtain a chip scale filter package film on the base film; obtaining a bare filter tip and flip-chip bonding the lower surface of the bare filter tip to a substrate via a metal ball; covering the upper surface of the bare filter tip with the chip scale filter package film using a vacuum hot press method, wherein the vacuum hot press conditions include a pressure of 0.1 to 0.5 MPa, a temperature of 50 to 70°C, and a time of 10 to 60 s; and curing at 150°C for 2 hours, cutting after curing is complete to obtain a packaged filter tip.

[0016] A fourth aspect of the present invention provides a filter tip, which is manufactured using the filter tip preparation method described in the third aspect. [Effects of the Invention]

[0017] The beneficial effects are as follows: The present invention provides a chip scale filter package film, which contains, by mass%, 55-70% silica, 14-24% epoxy resin, 15-20% phenoxy resin, 1-2.5% curing agent, 0.5-1.2% accelerator, and 0.3-0.9% colorant. The epoxy resin consists of polyurethane-modified bisphenol A type epoxy resin and a tetrafunctional epoxy resin. The molecular weight of the phenoxy resin is 50,000-150,000. The increased polarity of the polyurethane-modified bisphenol A type epoxy resin provides a stronger effect on silica, improving the surface performance of the silica. This method effectively improves the compatibility between polyurethane-modified bisphenol A epoxy resin and silica. The tetrafunctional epoxy resin has high reaction activity and can provide crosslinking fulcrums. The phenoxy resin improves the wettability of silica. By using phenoxy resin, polyurethane-modified bisphenol A epoxy resin, and tetrafunctional epoxy resin as a matrix resin, and by adjusting the ratio of the three components and controlling the silica particle size, the fluidity of the chip scale filter package film can be controlled. This improves curing efficiency under the catalytic conditions of a curing agent and accelerator, and further improves package efficiency. [Brief explanation of the drawing]

[0018] Hereinafter, in order to more clearly illustrate the examples of this specification or the technical solutions in the prior art, some drawings that may be used in the examples will be briefly introduced. However, the drawings in the following description represent only some examples of the present invention, and it will be obvious to those skilled in the art that other drawings can be obtained based on these drawings without any creative effort. [Figure 1] This is a flowchart of the method for preparing the chip-scale filter package film of the present invention. [Figure 2] This is a schematic diagram of the filter tip of the present invention. [Figure 3] This is a schematic diagram of the bare filter tip. [Figure 4] This is a diagram illustrating the package effect in Example 1 of the present application. [Figure 5]It is a package effect diagram in Example 2 of the present application. [Figure 6] It is a package effect diagram in Example 3 of the present application. [Figure 7] It is a package effect diagram in Comparative Example 1 of the present application. [Figure 8] It is a package effect diagram in Comparative Example 2 of the present application.

Embodiments for Carrying out the Invention

[0019] Hereinafter, the present invention will be specifically described while referring to specific embodiments and examples, whereby the advantages and various effects of the present invention will become clearer. Those skilled in the art should understand that these specific embodiments and examples are for explaining the present invention and do not limit the present invention.

[0020] Throughout the specification, unless otherwise specified, the terms used in this specification are understood to have the meanings generally used in the technical field. Therefore, unless specifically defined, all technical terms and scientific terms used in this specification have the same meanings as those generally understood by those skilled in the art to which the present invention pertains. In case of contradictions, this specification shall prevail.

[0021] Unless otherwise specified, each raw material, reagent, instrument, and equipment used in the present invention can be purchased from the market or obtained by existing methods.

[0022] The present application provides a chip scale filter package film, and the chip scale filter package film contains, by mass%, 55% - 70% of silica, 14% - 24% of epoxy resin, 15% - 20% of phenoxy resin, 1% - 2.5% of curing agent, 0.5% - 1.2% of accelerator, and 0.3% - 0.9% of colorant. The epoxy resin consists of a polyurethane-modified bisphenol A type epoxy resin and a tetrafunctional epoxy resin, and the molecular weight of the phenoxy resin is 50,000 - 150,000.

[0023] Specifically, the present invention provides a chip scale filter package film, which contains, by mass%, 55-70% silica, 14-24% epoxy resin, 15-20% phenoxy resin, 1-2.5% curing agent, 0.5-1.2% accelerator, and 0.3-0.9% colorant. The epoxy resin consists of polyurethane-modified bisphenol A type epoxy resin and a tetrafunctional epoxy resin. The molecular weight of the phenoxy resin is 50,000-150,000. The increased polarity of the polyurethane-modified bisphenol A type epoxy resin results in a stronger effect on silica, and the surface of silica This method effectively improves surface performance, enhances compatibility between polyurethane-modified bisphenol A epoxy resin and silica, and utilizes a tetrafunctional epoxy resin with high reaction activity that can provide crosslinking fulcrums. The phenoxy resin improves silica wetting properties, and by using a matrix resin consisting of phenoxy resin, polyurethane-modified bisphenol A epoxy resin, and tetrafunctional epoxy resin, and by adjusting the ratios of the three components and controlling the silica particle size, the fluidity of the chip scale filter package film can be controlled. Furthermore, curing efficiency is improved under the catalytic conditions of a curing agent and accelerator, and package efficiency is further enhanced.

[0024] In some possible embodiments, the particle size D50 of the silica is 7 to 10 μm.

[0025] This is because, by selecting silica with a large particle size as the filler material, on the one hand, it can play a certain inhibitory role, as the viscosity of the molding material decreases under temperature and pressure conditions due to the large particle size powder material, preventing it from becoming too fluid and flowing into the cavity, and on the other hand, it can be adjusted to an appropriate energy storage modulus and coefficient of thermal expansion. A preferred example is silica with a particle size D50 of 8.5 μm.

[0026] In some possible embodiments, the epoxy equivalent of the polyurethane-modified bisphenol A type epoxy resin is 230 to 260 g / eq, and the epoxy equivalent of the tetrafunctional epoxy resin is 95 to 125 g / eq.

[0027] In some possible embodiments, the epoxy resin comprises at least one of tetraglycidyl-1,3-bisaminomethylcyclohexane, tetraglycidyldiaminodiphenylmethane, and tetraglycidylxylenediamine.

[0028] Those skilled in the art will understand that this application controls the fluidity of a chip scale filter package film by using phenoxy resin, polyurethane-modified bisphenol A epoxy resin, and tetrafunctional epoxy resin as matrix materials and adjusting the ratios of the three. Phenoxy resin can improve the wetting properties of the filler material, provide toughness, and enhance the tackiness of the material, as well as control the appearance and rheology. Tetrafunctional epoxy resin has four epoxy groups, high reactive activity, can improve crosslinking density after curing, has good curing performance, good high temperature resistance, and excellent weather resistance and aging resistance.

[0029] In some possible embodiments, the curing agent is a latent curing agent containing dicyandiamide.

[0030] Latent curing agents, after being mixed with epoxy resin, can be stored stably at room temperature. When heated, they begin to dissolve near their melting point and harden very rapidly. The curing reaction temperature for dicyandiamide is 160-180°C, and it is usually used in combination with an accelerator.

[0031] In some possible embodiments, the accelerator is a latent accelerator containing an imidazole compound.

[0032] Latent curing accelerators can accelerate the reaction rate of epoxy resins and latent curing agents, reduce curing time, and improve production efficiency. Imidazole compounds such as 2-phenyl-4,5-dihydroxymethylimidazole can lower the curing reaction temperature of dicyandiamide.

[0033] In some possible embodiments, the colorant comprises carbon black having an average particle size of 5 nm.

[0034] Those skilled in the art will understand that colorants are used to color chip-scale filter package films, and in this application, the colorant may be carbon black with an average particle size of 5 nm.

[0035] Based on the overall concept of the invention, referring to Figure 1, the present application further provides a method for preparing a chip-scale filter package film as described in the first aspect, the preparation method is as follows: The first step is to stir-mix each component according to their respective mass percentages to obtain a first slurry, wherein the mass percentages of each component are, specifically, that the chip scale filter package film contains, by mass%, 55% to 70% silica, 14% to 24% epoxy resin, 15% to 20% phenoxy resin, 1% to 2.5% curing agent, 0.5% to 1.2% accelerator, and 0.3% to 0.9% coloring agent, and the epoxy resin consists of polyurethane-modified bisphenol A type epoxy resin and tetrafunctional epoxy resin, and the molecular weight of the phenoxy resin is 50,000 to 150,000. S2 involves transferring the first slurry to a bead mill and performing a dispersion process to obtain a uniformly dispersed second slurry. S3 involves vacuum degassing the second slurry to obtain a third slurry, The third slurry is applied to the base film and dried (S4), The process includes S5, which involves removing the base film after drying is complete to obtain a chip scale filter package film.

[0036] The method for preparing the chip-scale filter package film provided in this application is simple and easy to operate.

[0037] Based on the overall concept of the invention, a method for preparing a filter tip, wherein the preparation method is: A step to obtain a mixed slurry by stirring, bead milling, and vacuum degassing each component of the chip scale filter package membrane described in the first embodiment, wherein the mass % of each component is, specifically, that the chip scale filter package membrane contains, by mass %, 55% to 70% silica, 14% to 24% epoxy resin, 15% to 20% phenoxy resin, 1% to 2.5% curing agent, 0.5% to 1.2% accelerator, and 0.3% to 0.9% coloring agent, the epoxy resin consists of polyurethane-modified bisphenol A type epoxy resin and tetrafunctional epoxy resin, and the molecular weight of the phenoxy resin is 50,000 to 150,000 S21, S22, when the mixed slurry is applied to the base film and dried, a chip scale filter package film is obtained on the base film. S23 involves obtaining a bare filter chip and performing flip-chip bonding of the lower surface of the bare filter chip to a substrate via a metal sphere. S24 is a step of coating the upper surface of the bare tip of the filter with the chip scale filter package film by vacuum hot pressing, wherein the conditions for the vacuum hot pressing include a pressure of 0.1 to 0.5 MPa, a temperature of 50 to 70°C, and a time of 10 to 60 s. The process includes S25, which is cured at 150°C for 2 hours, and then cut after curing is complete to obtain a packaged filter tip.

[0038] Those skilled in the art will understand that, under vacuum hot-pressing conditions, the chip scale filter package film prepared with the above-mentioned proportions has a certain fluidity, allowing it to flow onto the substrate and make close contact with the top surface of the filter's bare chip, thus completing the packaging of the filter's bare chip. After the packaging is complete, it is cured so that the chip scale filter package film, the filter's bare chip, and the substrate form a single whole. Subsequently, by cutting, the desired size or packaged filter chip can be obtained, further meeting the packaging needs for miniaturized filter chips.

[0039] Based on the overall concept of the invention, the present application further provides a filter tip manufactured by the filter tip preparation method described in the third embodiment.

[0040] This is a schematic diagram of the filter tip provided in this application. As shown in Figures 2 and 3, it includes a metal sphere 1, a substrate 2, a cavity 3, a bare filter tip 4, and a chip scale filter package film 5. The lower surface of the bare filter tip 4 is welded to the substrate 2 via several metal spheres 1, and the chip scale filter package film 5 covers the bare filter tip 4 and contacts the substrate 2, thereby protecting the functional area of ​​the filter tip from contamination.

[0041] The present application will be further described below with reference to specific examples. It should be understood that these examples are for illustrative purposes only and do not limit the scope of the present application. Experimental methods in the following examples where specific conditions are not specified are generally measured according to Chinese national standards. Where there is no corresponding national standard, the experiment is carried out according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0042] (Example 1) The chip-scale filter package film of this embodiment contains the following components by mass: JPEG2026514615000002.jpg46138

[0043] Here, the molecular weight of the phenoxy resin is 100,000.

[0044] The chip-scale filter package film in this embodiment is prepared by the following steps. (1) Weigh each component of the raw materials according to the above mixing ratio and stir them uniformly to obtain the first slurry. (2) The first slurry is transferred to a bead mill and dispersed to obtain a second slurry that is uniformly dispersed. (3) The second slurry is degassed under vacuum to obtain the third slurry. (4) Apply the third slurry to the base film and let it dry. (5) After drying is complete, remove the base film to obtain the chip scale filter package film.

[0045] The chip-scale filter package film of this embodiment is applied to the package of a filter chip, and the specific package flow is as follows. (21) Each component of the raw materials is weighed according to the above mixing ratio, and a mixed slurry is obtained by stirring and mixing, bead milling and vacuum degassing. (22) The mixed slurry is applied to the base film and dried to obtain a chip scale filter package film on the base film. (23) A bare chip of the filter is obtained, and the underside of the bare chip of the filter is flip-chip bonded to the substrate via a metal ball. (24) The chip scale filter package film is coated onto the top surface of the bare tip of the filter by vacuum hot pressing to complete the package, the conditions for which the vacuum hot pressing is performed include a pressure of 0.3 MPa, a temperature of 50°C, and a time of 50 s. (25) Cure at 150°C for 2 hours, and after curing is complete, cut to obtain packaged filter tips. (Example 2)

[0046] The chip-scale filter package film of this embodiment contains the following components in mass percent: JPEG2026514615000003.jpg46139

[0047] Here, the molecular weight of the phenoxy resin is 100,000.

[0048] The method for preparing the chip-scale filter package film in this embodiment is the same as the method for preparing the chip-scale filter package film in Example 1.

[0049] The chip-scale filter package film of this embodiment is applied to the package of a filter chip, and the specific package flow is as follows. (21) Each component of the raw materials is weighed according to the above mixing ratio, and a mixed slurry is obtained by stirring and mixing, bead milling and vacuum degassing. (22) The mixed slurry is applied to the base film and dried to obtain a chip scale filter package film on the base film. (23) A bare chip of the filter is obtained, and the underside of the bare chip of the filter is flip-chip bonded to the substrate via a metal ball. (24) The chip scale filter package film is coated onto the top surface of the bare tip of the filter by vacuum hot pressing to complete the package, the conditions for which the vacuum hot pressing is performed include a pressure of 0.2 MPa, a temperature of 60°C, and a time of 30 s. (25) Cure at 150°C for 2 hours, and after curing is complete, cut to obtain packaged filter tips. (Example 3)

[0050] The chip-scale filter package film of this embodiment contains the following components in mass percent: JPEG2026514615000004.jpg45138

[0051] Here, the molecular weight of the phenoxy resin is 100,000.

[0052] The method for preparing the chip-scale filter package film in this embodiment is the same as the method for preparing the chip-scale filter package film in Example 1.

[0053] The chip-scale filter package film of this embodiment is applied to the package of a filter chip, and the specific package flow is as follows. (21) Each component of the raw materials is weighed according to the above mixing ratio, and a mixed slurry is obtained by stirring and mixing, bead milling and vacuum degassing. (22) The mixed slurry is applied to the base film and dried to obtain a chip scale filter package film on the base film. (23) A bare chip of the filter is obtained, and the underside of the bare chip of the filter is flip-chip bonded to the substrate via a metal ball. (24) The chip scale filter package film is coated onto the top surface of the bare tip of the filter by vacuum hot pressing to complete the package, the conditions for which the vacuum hot pressing is performed include a pressure of 0.1 MPa, a temperature of 70°C, and a time of 20 s. (25) Cure at 150°C for 2 hours, and after curing is complete, cut to obtain packaged filter tips. (Comparative Example 1)

[0054] The chip-scale filter package film of this comparative example contains the following components by mass: JPEG2026514615000005.jpg45128

[0055] Here, the epoxy equivalent of the bisphenol F type epoxy resin is 160-180 g / eq, and the molecular weight of the phenoxy resin is 100,000.

[0056] The method for preparing the chip scale filter package film in this comparative example is the same as the method for preparing the chip scale filter package film in Example 1.

[0057] The chip-scale filter package film of this comparative example is applied to the package of a filter chip, and the specific package flow is as follows. (21) Each component of the raw materials is weighed according to the above mixing ratio, and a mixed slurry is obtained by stirring and mixing, bead milling and vacuum degassing. (22) The mixed slurry is applied to the base film and dried to obtain a chip scale filter package film on the base film. (23) A bare chip of the filter is obtained, and the underside of the bare chip of the filter is flip-chip bonded to the substrate via a metal ball. (24) The chip scale filter package film is coated onto the top surface of the bare tip of the filter by vacuum hot pressing to complete the package, the conditions for which the vacuum hot pressing is performed include a pressure of 0.2 MPa, a temperature of 60°C, and a time of 30 s. (25) Cure at 150°C for 2 hours, and after curing is complete, cut to obtain packaged filter tips. (Comparative Example 2)

[0058] The chip-scale filter package film of this comparative example contains the following components by mass: JPEG2026514615000006.jpg46132

[0059] Here, the epoxy equivalent weight of the bisphenol F type epoxy resin is 160-180 g / eq, and the molecular weight of the acrylic resin is 300,000.

[0060] The method for preparing the chip scale filter package film in this comparative example is the same as the method for preparing the chip scale filter package film in Example 1.

[0061] The chip-scale filter package film of this comparative example is applied to the package of a filter chip, and the specific package flow is as follows. (21) Each component of the raw materials is weighed according to the above mixing ratio, and a mixed slurry is obtained by stirring and mixing, bead milling and vacuum degassing. (22) The mixed slurry is applied to the base film and dried to obtain a chip scale filter package film on the base film. (23) A bare chip of the filter is obtained, and the underside of the bare chip of the filter is flip-chip bonded to the substrate via a metal ball. (24) The chip scale filter package film is coated onto the top surface of the bare tip of the filter by vacuum hot pressing to complete the package, the conditions for which the vacuum hot pressing is performed include a pressure of 0.4 MPa, a temperature of 70°C, and a time of 60 s. (25) Cure at 150°C for 2 hours, and after curing is complete, cut to obtain packaged filter tips.

[0062] Rheology tests, gum penetration distance, copper sheet adhesion, thixotropy, glass transition temperature, thermal expansion coefficient, and storage modulus were performed on the chip scale filter package films provided in Examples 1-3 and Comparative Examples 1-2. The specific test flow is as follows.

[0063] 1. Rheology test: After applying the formulation to form a film, it was cut into 5cm x 5cm sample pieces. The lightly peeled film was removed, and the film material was heat-transferred to a thickness of 1000-1200 μm at 100°C. The viscosity was tested using a rheometer, and the fixing force was set to 2N. The viscosity was then tested at 50°C, 60°C, and 70°C.

[0064] 2. Gum penetration distance: After applying the formulation and forming a film, it was cut into 9cm x 9cm sample pieces. The lightly peeled film was removed and used to cover the bare chip of a filter that had already been flip-chip bonded to a substrate. The pieces were then vacuum hot-pressed and cured at 150°C for 2 hours. After cutting into individual finished products, the substrate was pried open and the gum penetration distance d was measured using an optical microscope. A "+" was marked for the functional area of ​​a filter chip where no gum penetration occurred, a "×" was marked for the functional area of ​​a filter chip where gum penetration occurred, and a "-" was marked if the gum did not cover the area around the chip (i.e., the gum was not in contact with the substrate).

[0065] 3. Adhesion of copper sheet: After applying the mixture to form a film, it was cut into 2mm x 2mm film pieces, transferred to the copper sheet, cured at 150°C for 2 hours, and then the cutting adhesion strength was tested using a universal tensile strength machine.

[0066] 4. Thixotropic coefficient (TI) test: The slurry obtained with the above formulation was tested using a Bohrerfeld DV1MRV viscometer (USA), rotor No. 21, at a test temperature of 30°C. The viscosity values ​​η1 at 0.5 rpm and η2 at 5 rpm were measured, and the result was TI = η1 / η2.

[0067] 5. Coefficient of thermal expansion and glass transition temperature: The cured samples were measured according to ASTME831-2019. The measurement parameters were: pre-pressure: 0.05 N, first scan: room temperature - 250°C (heating rate 10°C / min), second scan: room temperature - 250°C (heating rate 10°C / min). The curve data from the second heating interval was used.

[0068] 6. Storage Modulus Test: The size of the prepared test sample was 55 mm × 10 mm × 2 mm, and the storage modulus was tested using the ASTME2254-2018 standard method.

[0069] The test results are shown in Table 1. [Table 1]

[0070] As can be seen from the table above, by using silica with a large average particle size and adding a tetrafunctional epoxy resin, the resulting film can have lower fluidity and a higher thixotropy. Furthermore, when applied to the bare tip of the filter, the gum penetration distance d is such that it does not contaminate the filter's functional area. Additionally, using a phenoxy resin with a molecular weight of 100,000 results in better fluidity compared to using an acrylic resin with a molecular weight of 300,000, allowing it to coat the periphery of the filter tip and adhere to the substrate, forming a cavity. Finally, adding polyurethane-modified bisphenol A epoxy resin and phenoxy resin is advantageous for improving the adhesion of the film material to the substrate, which is beneficial for subsequent cutting into individual filter packages.

[0071] As can be seen from the package effect diagrams in Figures 4-8, when packaging a bare filter chip using the chip-scale filter package film prepared in Examples 1-3, gum infiltration occurs. However, the gum liquid does not penetrate to the functional area of ​​the filter chip and does not affect the normal operation of the filter. In Comparative Example 1, the gum infiltration is severe, and the gum liquid has already penetrated to the functional area of ​​the filter chip, affecting the normal operation of the filter. In Comparative Example 2, the gum liquid does not come into contact with the substrate, meaning that the packaging of the bare filter chip is not complete.

[0072] In summary, the chip-scale filter packaging film provided in this application has low fluidity and can cover the periphery of the filter chip, thereby forming a sealed cavity between the chip and the substrate, preventing contamination of the filter functional area, and resulting in a high glass transition temperature and storage modulus. During use, it covers the filter chip and prevents gum from entering the cavity and contaminating the filter functional area, simplifying the filter packaging method, improving packaging efficiency and yield, and reducing packaging costs. Furthermore, the film can be directly applied to the filter molding, reducing the filter package size. By producing a film thickness corresponding to the total height of the flip filter chip structure and reducing the size after packaging accordingly, future miniaturization needs can be better met.

[0073] Finally, since “including,” “consisting of,” or any other variation thereof are intended to cover non-exclusive inclusion, a process, method, article, or apparatus that includes a set of elements includes not only those elements but also other elements not explicitly listed, or elements specific to such a process, method, article, or apparatus.

[0074] While preferred embodiments of the present invention have been described, those skilled in the art, knowing the basic creative concepts, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including not only the preferred embodiments but also all changes and modifications that fall within the scope of the present invention.

[0075] Clearly, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the invention. Thus, the present invention is also intended to include such modifications and variations if they fall within the scope of the claims of the present invention and the equivalent art. [Explanation of Symbols]

[0076] 1...Metal sphere, 2...Substrate, 3...Cavity, 4...Bare filter chip, 41...Functional area of ​​filter chip, 42...Non-functional area of ​​filter, 5...Chip-scale filter package film.

Claims

1. A chip scale filter package film comprising, by mass%, 55% to 70% silica, 14% to 24% epoxy resin, 15% to 20% phenoxy resin, 1% to 2.5% curing agent, 0.5% to 1.2% accelerator, and 0.3% to 0.9% colorant, wherein the epoxy resin consists of polyurethane-modified bisphenol A type epoxy resin and tetrafunctional epoxy resin, and the molecular weight of the phenoxy resin is 50,000 to 150,000. The particle size D50 of the silica is 7 to 10 μm. The epoxy equivalent of the polyurethane-modified bisphenol A type epoxy resin is 230 to 260 g / eq, and the epoxy equivalent of the tetrafunctional epoxy resin is 95 to 125 g / eq. The tetrafunctional epoxy resin comprises at least one of tetraglycidyl-1,3-bisaminomethylcyclohexane, tetraglycidyldiaminodiphenylmethane, and tetraglycidylxylenediamine. Here, the sum of the mass percentages of the above components is 100%. A chip-scale filter package film characterized by the following features.

2. The chip scale filter package film according to claim 1, characterized in that the curing agent is a latent curing agent containing dicyandiamide.

3. The chip-scale filter package membrane according to claim 2, characterized in that the accelerator is a latent accelerator containing an imidazole compound.

4. The chip-scale filter package film according to claim 3, characterized in that the coloring agent contains carbon black having an average particle size of 5 nm.

5. The first step is to stir-mix each component according to their respective mass percentages to obtain a first slurry, wherein the mass percentages of each component specifically include 55% to 70% silica, 14% to 24% epoxy resin, 15% to 20% phenoxy resin, 1% to 2.5% curing agent, 0.5% to 1.2% accelerator, and 0.3% to 0.9% coloring agent, the epoxy resin being a polyurethane-modified bisphenol A type epoxy resin and a tetrafunctional epoxy resin, the molecular weight of the phenoxy resin being 50,000 to 150,000, and the sum of the mass percentages of the components being 100%, S1 and S2 involves transferring the first slurry to a bead mill and performing a dispersion process to obtain a uniformly dispersed second slurry. S3 involves vacuum degassing the second slurry to obtain a third slurry, S4 involves applying the third slurry to the base film and drying it, A method for preparing a chip scale filter package film according to any one of claims 1 to 4, comprising S5, which involves removing the base film after drying is completed to obtain a chip scale filter package film.

6. A step of obtaining a mixed slurry by stirring, bead milling, and vacuum degassing each component of the chip scale filter package membrane according to any one of claims 1 to 4, wherein the mass percentage of each component specifically comprises 55% to 70% silica, 14% to 24% epoxy resin, 15% to 20% phenoxy resin, 1% to 2.5% curing agent, 0.5% to 1.2% accelerator, and 0.3% to 0.9% coloring agent, wherein the epoxy resin consists of polyurethane-modified bisphenol A type epoxy resin and tetrafunctional epoxy resin, and the molecular weight of the phenoxy resin is 50,000 to 150,000, and the sum of the mass percentages of the components is 100%, and The step of applying the mixed slurry to a base film and drying it to obtain a chip scale filter package film on the base film, The steps include obtaining a bare chip of the filter and flip-chip bonding the lower surface of the bare chip of the filter to a substrate via a metal ball, A step of coating the upper surface of the bare tip of the filter with the chip scale filter package film by vacuum hot pressing, wherein the conditions for the vacuum hot pressing include a pressure of 0.1 to 0.5 MPa, a temperature of 50 to 70°C, and a time of 10 to 60 s. A method for preparing a filter tip, comprising the steps of curing at 150°C for 2 hours, cutting after curing is complete to obtain a packaged filter tip.

7. A filter tip characterized by being manufactured by the filter tip preparation method described in claim 6.

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