UV (ultraviolet) viscosity-reduced film and preparation method thereof

Abstract

The invention belongs to the technical field of UV visbreaking polymers, and particularly relates to a UV visbreaking film and a preparation method thereof. Wherein the UV viscosity-reducing film sequentially comprises a base film (1), a first viscosity-reducing adhesive layer (5), a second viscosity-reducing adhesive layer (4) and a release film (3) from bottom to top, the first viscosity-reducing adhesive layer (5) and the second viscosity-reducing adhesive layer (4) both comprise a photoinitiator, the photoinitiator in the first viscosity-reducing adhesive layer (5) is 1-hydroxy-cyclohexyl phenyl ketone, and the content of the photoinitiator in the formula of the adhesive layer is 0.1%-10% by mass; a photoinitiator in the second viscosity-reducing adhesive layer (4) is bis (2, 4, 6-trimethylbenzoyl) phenyl phosphine oxide, and the content of the photoinitiator in the adhesive layer formula is 0.1-10% by mass; in the preparation method, ultraviolet irradiation precuring is carried out, so that the UV viscosity-reducing film has light selectivity and high cohesion strength, and the residual adhesive is remarkably reduced.

Description

Technical Field

[0001] This invention belongs to the field of UV-resistant polymer technology, specifically relating to a UV-resistant film and its preparation method. Background Technology

[0002] UV anti-adhesion films exhibit strong adhesion before UV irradiation, but this adhesion significantly decreases after irradiation. During semiconductor processing, these films firmly adhere to wafers, QFNs, DFNs, and other workpieces, providing fixation and protection. After processing, UV irradiation drastically reduces or eliminates the adhesion, allowing for easy peeling and pickup of the processed workpieces. Therefore, UV anti-adhesion films are widely used in semiconductor manufacturing processes such as wafer dicing, wafer grinding, and packaging dicing.

[0003] UV anti-adhesion films generally consist of a base film, an anti-adhesion adhesive layer, and a release film. The anti-adhesion adhesive layer is located between the base film and the anti-adhesion adhesive layer. The base film is the carrier of the anti-adhesion adhesive and also plays a supporting role in the semiconductor packaging and cutting process. The anti-adhesion adhesive mainly plays the role of adhesion and loss of adhesion after UV irradiation. The release film is mainly used to protect the anti-adhesion adhesive and is peeled off when using the anti-adhesion film. The release film can also act as a carrier when using transfer coating processes.

[0004] With the widespread application of UV anti-adhesion films in semiconductor manufacturing processes, residual adhesive often remains on the surface of the workpiece after UV irradiation and peeling off the film. During wafer or packaging semiconductor workpiece processing, there is a certain probability of residual adhesive lumps or marks on the workpiece. This is especially true when the workpiece surface has printed logos, which increases the likelihood of residual adhesive and affects product yield. These residual adhesive problems require manufacturers to invest additional manpower and resources in subsequent cleaning, increasing semiconductor manufacturing costs.

[0005] Patent CN117624498A discloses a polyacrylate with photocurable alkenyl groups in its side chains and a UV-resistant adhesive composition. The UV-resistant adhesive composition incorporating such polyacrylate with photocurable alkenyl groups in its side chains can fully wet epoxy molding compounds for electronic components, exhibiting high adhesion to the epoxy molding compounds. Simultaneously, the UV-resistant adhesive composition eliminates the need for low-molecular-weight UV monomers and UV prepolymers. After curing with low-energy UV LED irradiation, the peel strength of the UV-resistant adhesive composition is significantly reduced, and residue is avoided.

[0006] Patent CN111218225A discloses a non-adhesive UV-resistant protective film and its preparation method. This invention provides a UV-resistant composition and a UV-resistant protective film material containing the composition. The composition, formed by acrylate monomers and a specific acrylate oligomer system containing reactive groups, serves as the UV-resistant layer material. This improves the peel strength of the UV-resistant protective film before UV irradiation and reduces the peel strength after UV irradiation, thereby improving the accuracy of fixation and pickup efficiency.

[0007] However, the UV anti-adhesion films disclosed in the current technology have the characteristics of low adhesive residue and easy peeling, but they also have problems such as high raw material costs or high difficulty in controlling the synthesis process. Summary of the Invention

[0008] The purpose of this invention is to provide a light-selective UV anti-adhesion film with easy peeling, low adhesive residue, and its preparation method.

[0009] The technical solution of the present invention is that, on one hand, the present invention provides a UV anti-adhesion film, which includes, from bottom to top, a base film, a first anti-adhesion layer, a second anti-adhesion layer and a release film. Both the first anti-adhesion layer and the second anti-adhesion layer include photoinitiators, and the initiators in the first anti-adhesion layer and the second anti-adhesion layer include different types.

[0010] Furthermore, the photoinitiator in the first anti-tack layer is 1-hydroxy-cyclohexylphenyl ketone (184), and the content of the photoinitiator in the first anti-tack layer is 0.1% to 10% by mass; the photoinitiator in the second anti-tack layer is bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (819), and its content in the second anti-tack layer is 0.1% to 10% by mass.

[0011] Furthermore, the photoinitiator in the first anti-adhesion layer is 1-hydroxy-cyclohexylphenyl ketone, and the content of the photoinitiator in the first anti-adhesion layer is 1% to 6% by mass; the photoinitiator in the second anti-adhesion layer is bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and its content in the second anti-adhesion layer is 0.5% to 3% by mass.

[0012] Furthermore, the base film is made of PET or PO, with a thickness between 20μm and 200μm and a light transmittance of over 90%; both the first and second anti-adhesion layers are acrylic pressure-sensitive adhesives, with a total thickness between 10μm and 20μm, a peel strength of 5 N / 25mm to 20 N / 25mm before UV irradiation, and a peel strength of less than 0.5 N / 25mm after UV irradiation; the release film is a PET film treated with fluorine or silicone release agent, with a thickness between 10μm and 100μm and a release force of 0.05 N / 25mm to 0.15 N / 25mm.

[0013] Furthermore, the base film is a PO film with a thickness between 50μm and 150μm, a light transmittance of over 92%, and a haze of less than 50%; both the first and second anti-adhesive layers are acrylic pressure-sensitive adhesives, with a total thickness between 12μm and 15μm, a peel strength between 8 N / 25mm and 15 N / 25mm before UV irradiation, and a peel strength below 0.2 N / 25mm after UV irradiation; the release film is a PET film treated with fluorine or silicone release agent, with a thickness between 15μm and 50μm, and a release force of 0.08 N / 25mm to 0.12 N / 25mm.

[0014] Furthermore, the second anti-tack layer has a thickness of 4μm to 8μm, and the first anti-tack layer has a thickness of 6μm to 12μm. Both the second and first anti-tack layers include polyacrylate resin, acrylate reactive diluent, curing agent, and leveling agent.

[0015] Furthermore, the molecular weight of the polyacrylate resin ranges from 50,000 to 900,000, and the content of the polyacrylate resin in the adhesive layer formulation is 10% to 90% by mass percentage; the acrylate reactive diluent includes diethylene glycol diacrylate (DEGDA), triethylene glycol triacrylate (TEGDA), dipropylene glycol diacrylate (DPGDA), tripropylene glycol triacrylate (TPGDA), neopentyl glycol diacrylate (NPGDA), hexanediol diacrylate (HDDA), trimethylolpropane triacrylate (TMPTA), and dimethylolpropane diacrylate. The adhesive comprises one or two of propane triacrylate (DTMPTTA), pentaerythritol triacrylate (PETA), and dipentaerythritol hexaacrylate (DPHA); the content of the acrylate reactive diluent in the adhesive layer formulation is 5% to 65% by mass; the curing agent is an isocyanate curing agent, and the content of the curing agent in the adhesive layer formulation is 0.1% to 5% by mass; the leveling agent is one or two of aryl-modified, polyester-modified, or polyether-modified silicone additives, and the content of the leveling agent in the adhesive layer formulation is 0.01% to 0.5% by mass.

[0016] Furthermore, the polyacrylate resin content in the adhesive layer formulation is 40%~75% by mass; the acrylate reactive diluent content in the adhesive layer formulation is 10%~40% by mass; the curing agent is an L-75 or L-45 isocyanate curing agent, and its content in the adhesive layer formulation is 0.5%~3% by mass; the leveling agent content in the adhesive layer formulation is 0.05%~0.2% by mass.

[0017] Furthermore, the polyacrylate resin is selected from one of the following materials: PS8230, PS8231, and PS8233 from Shimei Company; LT-0355, LT-0356, and LT-3022 from Lvtian Company; and 70325 from Changxing Company. The leveling agent is selected from one or two of the following materials: aryl-modified silicone additives using BYK-322 and BYK-323; polyester-modified silicone additives using BYK-310; and polyether-modified silicone additives using BYK-300, BYK-301, BYK-302, BYK-306, BYK-307, BYK-330, BYK-331, BYK-333, BYK-335, BYK-341, and BYK-344.

[0018] A second aspect of the present invention also provides a method for preparing the UV anti-adhesion film of the first aspect of the present invention, comprising the following steps: After weighing the raw materials according to the first and second anti-tack layer formulations, a certain proportion of solvent was added to each, and the mixture was stirred evenly with a high-speed stirrer to obtain the first and second anti-tack layer solutions. Then, the second and first anti-tack layer solutions were coated onto the release surface of the release film using a double-slit coating method. After drying, the mixture was subjected to an energy level of less than or equal to 100 mW / cm². 2 Furthermore, after irradiation with ultraviolet light of wavelength 405nm~450nm for 10s~15s, it is combined with the base film to obtain a UV anti-adhesion film.

[0019] The advantage of this invention over the prior art lies in: 1. The UV anti-adhesion film of the present invention comprises two anti-adhesion layers, each containing a different photoinitiator. The second anti-adhesion layer (4) contains photoinitiator 819, while the first anti-adhesion layer (5) contains photoinitiator 184. The maximum ultraviolet absorption wavelengths of photoinitiator 819 are 370nm and 405nm, and can even reach 450nm, while the maximum ultraviolet absorption wavelengths of photoinitiator 184 are 246nm, 280nm, and 333nm. Therefore, by utilizing the different maximum ultraviolet absorption wavelengths of the two photoinitiators and adding them to different anti-adhesion layers respectively, the UV anti-adhesion film achieves light selectivity.

[0020] 2. In the preparation method of the present invention, the energy is not greater than 100mW / cm 2 Pre-curing is achieved by irradiating with ultraviolet light with a wavelength of 405nm~450nm for 10s~15s. Attached Figure Description

[0021] These and / or other aspects and advantages of the present invention will become clearer and more readily understood from the following detailed description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the structure of the UV anti-adhesion film obtained in an embodiment of the present invention. Detailed Implementation

[0022] Example 1 A UV anti-adhesion film, the structural schematic diagram of which is shown below. Figure 1 As shown, from bottom to top, the structure includes a base film 1, a first anti-adhesive layer 5, a second anti-adhesive layer 4, and a release film 3. The total thickness of the first anti-adhesive layer 5 and the second anti-adhesive layer 4 is 14~16μm, wherein the thickness of the second anti-adhesive layer 4 is 4~5μm, and the content of photoinitiator 819 is 0.9%. The thickness of the first anti-adhesive layer 5 is 10~11μm, and the content of photoinitiator 184 is 1.9%. The specific formulation is shown in Table 1.

[0023] Table 1. Formulations of each adhesive layer in the UV anti-adhesion film of the examples. The preparation method is as follows: Weigh each component according to the formula, add ethyl acetate for dilution, and mix evenly with a high-speed stirrer to obtain the anti-tack solution. Then, using a slot coating process, coat the second anti-tack layer and the first anti-tack layer onto a 36μm thick release film 3. Dry the film at 80℃~110℃ at a speed of 15m / min, and then pass it through an oven with an energy of 90mW / cm². 2 After irradiation with ultraviolet light with a wavelength of 405nm~450nm for 12s, it is combined with a PO film with a thickness of 150μm to obtain a UV anti-adhesion film.

[0024] Comparative Example 1 To compare the peelability and residue effect of a light-selectable UV anti-adhesive film and two UV anti-adhesive films with the same type of photoinitiator, a UV anti-adhesive film with the same total thickness of the anti-adhesive layer as in Example 1 was fabricated. The only difference from Example 1 was that both the first anti-adhesive layer 5 and the second anti-adhesive layer 4 used photoinitiator 819.

[0025] Comparative Example 2 To compare the peelability and residue effect of a light-selectable UV anti-adhesive film and a UV anti-adhesive film without UV pre-curing, a UV anti-adhesive film of Comparative Example 2 with the same total thickness of the anti-adhesive layer was prepared. The only difference from Example 1 is that the UV pre-curing step was omitted in the preparation process, and the film was directly laminated with the PO film after drying.

[0026] Tests and results: The prepared UV anti-adhesion film was subjected to peel strength tests before and after UV irradiation, as well as tests to examine its ease of peeling and residual adhesive effect.

[0027] UV peel strength test method: First, cut the UV anti-adhesion film into test strips 25mm wide and 200mm long. After removing the release film, attach the strips to a stainless steel plate and roll them back and forth three times with a 2kg roller. After 20 minutes, use a tensile testing machine at a peeling speed of 300mm / min to test the peel strength of the anti-adhesion film. Make three parallel test strips and take the average of the three test data as the UV peel strength of the anti-adhesion film.

[0028] UV peel strength test method: First, cut the UV anti-adhesion film into test strips 25mm wide and 200mm long. After removing the release film, attach the strips to a stainless steel plate and roll them back and forth three times with a 2kg roller. After standing for 20 minutes, the energy used should not be less than 400mW / cm². 2The surface of the anti-adhesion film was irradiated with ultraviolet light from a mercury lamp for 30 seconds. The peeling force of the anti-adhesion film was tested using a tensile testing machine at a peeling speed of 300 mm / min. Three test strips were made in parallel, and the average value of the three test data was taken as the peeling force of the anti-adhesion film after ultraviolet light.

[0029] Test methods for peelability and residual adhesive effect: The UV anti-adhesion film is adhered to an uncut chip. After cutting, observe for any missing cores. Then, use an energy level of not less than 400mW / cm². 2 Irradiate the chip with a mercury lamp (ultraviolet light wavelength covering 200nm~450nm) for 30s, observe the peeling process while peeling off the chip, and observe whether there is residual adhesive on the chip bonding surface through an optical microscope.

[0030] The test results are shown in Table 2.

[0031] Table 2 Test Results of Examples and Comparative Examples (Note: "Flying chip" refers to the chip scattering during the cutting process because the anti-adhesion film could not firmly adhere to the chip.) In Example 1, the UV anti-adhesion film has enhanced cohesive strength by pre-curing the second anti-adhesion adhesive layer 4 near the chip bonding surface under a specific wavelength of ultraviolet light, thereby reducing the risk of adhesive residue on the chip.

[0032] In contrast to Example 1, both the second anti-adhesion layer 4 and the first anti-adhesion layer 5 contain the same type of photoinitiator and cannot be selective for light. Therefore, when UV pre-curing is performed, both anti-adhesion layers will be pre-cured, which greatly reduces the peel force before UV exposure. This makes it impossible for the anti-adhesion film to firmly adhere to the chip, resulting in chip failure.

[0033] In Comparative Example 2, although the same anti-tack adhesive layer design as in Example 1 was used, UV pre-curing was not employed, resulting in residual adhesive.

[0034] The embodiments of this application will be described in further detail below. Obviously, the described embodiments are only a part of the embodiments of this application, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0035] The terms “first,” “second,” etc. (if applicable) in the specification and claims are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data used in this way can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion, such as a process, method, system, product, or apparatus that comprises a series of steps or units, not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0036] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0037] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A UV anti-adhesion film, characterized in that, From bottom to top, the layers include a base film (1), a first adhesive layer (5), a second adhesive layer (4), and a release film (3). Both the first adhesive layer (5) and the second adhesive layer (4) contain photoinitiators, and the types of photoinitiators in the first adhesive layer (5) and the second adhesive layer (4) are different.

2. The UV anti-adhesion film according to claim 1, characterized in that, The photoinitiator in the first anti-adhesion layer (5) is 1-hydroxy-cyclohexylphenyl ketone, and the content of the photoinitiator in the first anti-adhesion layer (5) is 0.1% to 10% by mass percentage; The photoinitiator in the second anti-adhesion layer (4) is bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and its content in the second anti-adhesion layer (4) is 0.1% to 10% by mass percentage.

3. The UV anti-adhesion film according to claim 1, characterized in that, The photoinitiator in the first anti-adhesion layer (5) is 1-hydroxy-cyclohexylphenyl ketone, and the content of the photoinitiator in the first anti-adhesion layer (5) is 1% to 6% by mass percentage; The photoinitiator in the second anti-adhesion layer (4) is bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and its content in the second anti-adhesion layer (4) is 0.5%~3% by mass percentage.

4. The UV anti-adhesion film according to claim 1, characterized in that, The base film (1) is made of PET or PO, with a thickness between 20μm and 200μm and a light transmittance of over 90%. The first anti-adhesion layer (5) and the second anti-adhesion layer (4) are both acrylic pressure-sensitive adhesives. The total thickness of the first anti-adhesion layer (5) and the second anti-adhesion layer (4) is between 10 μm and 20 μm. The peel strength before ultraviolet irradiation is 5 N / 25 mm to 20 N / 25 mm, and the peel strength after ultraviolet irradiation is less than 0.5 N / 25 mm. The release film (3) is a PET film treated with fluorine or silicone release agent, with a thickness between 10μm and 100μm and a release force of 0.05 N / 25mm to 0.15 N / 25mm.

5. The UV anti-adhesion film according to claim 1, characterized in that, The base film (1) is a PO film with a thickness between 50μm and 150μm, a light transmittance of more than 92%, and a haze of less than 50%. The first anti-adhesion layer (5) and the second anti-adhesion layer (4) are both acrylic pressure-sensitive adhesives. The total thickness of the first anti-adhesion layer (5) and the second anti-adhesion layer (4) is between 12μm and 15μm. The peel strength before ultraviolet irradiation is between 8 N / 25mm and 15 N / 25mm, and the peel strength after ultraviolet irradiation is below 0.2 N / 25mm. The release film (3) is a PET film treated with fluorine or silicone release agent, with a thickness between 15μm and 50μm and a release force of 0.08 N / 25mm to 0.12 N / 25mm.

6. The UV anti-adhesion film according to claim 1, characterized in that, The second anti-tack layer (4) has a thickness of 4μm to 8μm, and the first anti-tack layer (5) has a thickness of 6μm to 12μm. Both the second anti-tack layer (4) and the first anti-tack layer (5) include polyacrylate resin, acrylate reactive diluent, curing agent and leveling agent.

7. The UV anti-adhesion film according to claim 6, characterized in that, The molecular weight of the polyacrylate resin is between 50,000 and 900,000, and the content of the polyacrylate resin in the adhesive layer formulation is 10% to 90% by mass. The acrylate reactive diluent includes one or two of the following: diethylene glycol diacrylate, triethylene glycol triacrylate, dipropylene glycol diacrylate, tripropylene glycol triacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, trimethylolpropane triacrylate, dimethylolpropane triacrylate, pentaerythritol triacrylate, and dipentaerythritol hexaacrylate; the content of the acrylate reactive diluent in the adhesive layer formulation is 5% to 65% by mass. The curing agent is an isocyanate-based curing agent, and the content of the curing agent in the adhesive layer formulation is 0.1% to 5% by mass. The leveling agent is one or two of aryl-modified, polyester-modified, or polyether-modified silicone additives, and its content in the adhesive layer formulation is 0.01% to 0.5% by mass percentage.

8. The UV anti-adhesion film according to claim 6, characterized in that, The polyacrylate resin content in the adhesive layer formulation is 40% to 75% by mass percentage. The content of the acrylate reactive diluent in the formulation of the adhesive layer is 10% to 40% by mass percentage; The curing agent is an L-75 or L-45 isocyanate curing agent, and its content in the adhesive layer formulation is 0.5% to 3% by mass. The leveling agent is present in the formulation of the adhesive layer at a content of 0.05% to 0.2% by mass.

9. The UV anti-adhesion film according to claim 6, characterized in that, The polyacrylate resin is selected from one of the following materials: PS8230, PS8231, and PS8233 from Shimei Company; LT-0355, LT-0356, and LT-3022 from Lvtian Company; and 70325 from Changxing Company. The leveling agent is selected from one or two of the following materials: aryl-modified silicone additives BYK-322 and BYK-323; polyester-modified silicone additives BYK-310; and polyether-modified silicone additives BYK-300, BYK-301, BYK-302, BYK-306, BYK-307, BYK-330, BYK-331, BYK-333, BYK-335, BYK-341, and BYK-344.

10. A method for preparing a UV anti-adhesion film as described in any one of claims 1-9, characterized in that: Includes the following steps: After weighing the raw materials according to the formulas for the first anti-adhesive layer (5) and the second anti-adhesive layer (4), a certain proportion of solvent is added and stirred evenly to obtain the first anti-adhesive solution and the second anti-adhesive solution. The second anti-adhesive solution and the first anti-adhesive solution are coated on the release surface of the release film (3) using a double-layer slit coating method. After drying, the solution is tested by passing it through an energy level of less than or equal to 100mW / cm. 2 After being irradiated with ultraviolet light with a wavelength of 405nm~450nm for 10s~15s, it is combined with the base film (1) to obtain a UV anti-sticking film.

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