Preparation method of UV viscosity-reducing glue and UV viscosity-reducing adhesive tape

Abstract

The invention provides a preparation method of UV viscosity-reducing glue and a preparation method of a UV viscosity-reducing adhesive tape, and relates to the technical field of adhesives. The preparation method comprises the following steps: firstly, carrying out a first-step polymerization reaction to obtain an acrylate main adhesive; modifying the acrylate main adhesive by using a monomer containing an isocyanate group and two double bonds through a second-step reaction, namely introducing high-density double bonds into the acrylate main adhesive by using a reaction between an active functional group on a main chain and the isocyanate group to obtain a modified acrylate main adhesive solution; and finally, mixing the modified acrylate main glue solution with other additives such as a cross-linking agent, a photoinitiator and the like to obtain the UV viscosity-reducing glue. The viscosity of the UV viscosity-reducing adhesive tape prepared by adopting the UV viscosity-reducing adhesive water prepared by the invention is large enough before UV irradiation, a precise wafer in a high-speed cutting process can be well fixed, the viscosity of the UV viscosity-reducing adhesive tape is small enough after UV irradiation, automatic picking is convenient, and the adhered surface of a chip is completely free of residual adhesive.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, and in particular to a method for preparing a UV viscosity-reducing glue and a UV viscosity-reducing tape. Background Art

[0002] In recent years, the great progress made in the field of electronic equipment and artificial intelligence has benefited greatly from the continuous iteration of semiconductor chips and advanced packaging integration technology. Higher computing power, heat dissipation requirements, and the trend of 2.5D / 3D packaging have made the size of chips smaller and thinner, which has put forward higher requirements for wafer processing. During the wafer cutting process, the UV adhesive tape needs to have better viscosity to fix the cut wafer; after the wafer cutting is completed, the UV adhesive tape will be UV-irradiated before the automatic picking process to reduce its viscosity, so as to facilitate the separation of the UV adhesive tape from the chip, and it is required that there is no tape residue on the chip to be bonded. However, the UV adhesive tape prepared by the existing UV adhesive glue is difficult to meet the above requirements at the same time. For example, the viscosity of the UV adhesive tape before UV light irradiation is not large enough, and the UV adhesive tape cannot fix the cut wafer; the viscosity of the UV adhesive tape after UV light irradiation is still too large, resulting in the failure of automatic picking of the machine or the cohesive damage of residual adhesive on the bonded surface of the chip, which has a serious impact on the appearance or subsequent electrical properties of the chip. Summary of the invention

[0003] The problem solved by the present invention is that it is difficult for the UV anti-viscosity tape prepared by the existing UV anti-viscosity glue to simultaneously meet the following requirements: before ultraviolet light irradiation, the viscosity of the UV anti-viscosity tape is large enough so that the UV anti-viscosity tape can fix the cut wafer; after ultraviolet light irradiation, the viscosity of the UV anti-viscosity tape is small enough to facilitate automatic picking by the machine and avoid residual glue on the bonded surface of the chip.

[0004] In order to solve the above problems, the present invention provides a method for preparing UV viscosity-reducing glue, comprising:

[0005] Step S1: Under an inert gas protection atmosphere, subjecting the first mixture to a first polymerization reaction to obtain an acrylate main glue solution; wherein, the first mixture comprises, by weight: 20-90 parts of soft monomers, 0.5-40 parts of hard monomers, 0.5-20 parts of functional monomers, 0.5-1 parts of thermal initiators and 50-200 parts of organic solvents;

[0006] Step S2: adding a second mixture to the acrylate master glue solution to carry out a second step reaction to obtain a modified acrylate master glue solution; wherein the second mixture comprises, by weight: 2-10 parts of a modified monomer, 0.02-0.04 parts of a catalyst and 0.02-0.04 parts of an antioxidant; the modified monomer is a monomer containing an isocyanate group and two double bonds;

[0007] Step S3: adding a third mixture to the modified acrylate main glue solution, mixing evenly, to obtain a UV viscosity-reducing glue; wherein, by weight, the third mixture comprises: 1-6 parts of a cross-linking agent and 1-6 parts of a photoinitiator;

[0008] Wherein, in step S2, the structural formula of the monomer containing an isocyanate group and two double bonds is as shown in formula (1):

[0009]

[0010] In formula (1), m and n are independently selected from integers of 1-10, and R is selected from one of a C1-C10 alkyl group, a phenyl group and a cyclohexyl group.

[0011] Optionally, in step S1, the first mixture further comprises 0.1-10 parts of a photosensitive comonomer.

[0012] Optionally, the photosensitive comonomer includes at least one of acryloxybenzophenone, acryloxyethoxybenzophenone, and acryloxybutoxybenzophenone.

[0013] Optionally, in step S2, the monomer containing an isocyanate group and two double bonds includes at least one of 1,1-bis(acryloyloxymethyl)ethyl isocyanate, 1,1-bis(acryloyloxyethyl)ethyl isocyanate and 1,2-bis(acryloyloxymethyl)cyclohexane isocyanate.

[0014] Optionally, in step S1, the soft monomer includes at least one of (meth) alkyl acrylates with a branched or linear structure between C7 and C15; the hard monomer includes at least one of methyl methacrylate, ethyl acrylate and isobornyl acrylate; the functional monomer includes at least one of acrylic acid, methacrylic acid and hydroxyethyl acrylate; the thermal initiator includes at least one of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptylonitrile and dibenzoyl peroxide; and the organic solvent includes at least one of ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, benzene and toluene.

[0015] Optionally, in step S2, the catalyst includes dibutyltin dilaurate, and the antioxidant includes at least one of a phenolic antioxidant, an amine antioxidant and an organic phosphite antioxidant.

[0016] Optionally, in step S3, the cross-linking agent includes at least one of a multifunctional isocyanate, a multifunctional aziridine, a high-valent metal acid ester and a metal chelate; the multifunctional isocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate and hexamethylene diisocyanate; the photoinitiator includes at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propanone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide and α-hydroxy ketone.

[0017] Optionally, in step S1, the temperature of the first polymerization reaction is 60-90°C and the time is 8-14h; in step S2, the temperature of the second polymerization reaction is 40-60°C and the time is 10-60min.

[0018] The present invention also provides a method for preparing a UV anti-viscosity tape, comprising:

[0019] Step M1: coating the UV viscosity-reducing glue as described above on the base film, and drying it to obtain a UV viscosity-reducing glue layer;

[0020] Step M2: affixing a release film on the surface of the UV anti-viscosity adhesive layer to obtain a UV anti-viscosity adhesive tape.

[0021] Optionally, in step M1, the thickness of the base film is 50-200 μm, and the thickness of the UV viscosity-reducing adhesive layer is 5-50 μm.

[0022] Compared with the prior art, the present invention first obtains an acrylate main glue through a first step polymerization reaction; then, through a second step reaction, the acrylate main glue is modified by a monomer containing an isocyanate group and two double bonds, thereby introducing high-density double bonds into the acrylate main glue to obtain a modified acrylate main glue solution; finally, the modified acrylate main glue solution is mixed with a crosslinking agent and a photoinitiator to obtain a UV viscosity-reducing glue. The main component of the adhesive layer in the UV anti-viscosity tape prepared by using the UV anti-viscosity glue is a modified acrylate main glue. During the anti-viscosity process of UV irradiation treatment, the main chain in the modified acrylate main glue molecule is in a locked state, and the free movement of the entire molecular chain is limited. The high-density double bonds introduced on the main chain can move locally, which can effectively improve the cross-linking efficiency of the cross-linking reaction during the UV irradiation treatment. The main chain of the modified acrylate main glue molecule has abundant hydrogen donors (such as hydroxyl, carboxyl and tertiary hydrogen on the side chain), which can undergo dehydrogenation with the photoreactive group. Under the above dual effects, it is easier to form a cross-linked structure, further improving the overall cohesion of the adhesive layer in the UV anti-viscosity tape, so that the UV anti-viscosity tape after UV irradiation treatment has a smaller viscosity. In addition, the modified acrylate main glue molecule has soft and hard segments and functional monomers with strong polarity on the main chain structure, which also makes the UV anti-viscosity tape before UV irradiation treatment have sufficient viscosity. In summary, the UV anti-viscosity tape prepared by the UV anti-viscosity glue prepared by the present invention has a sufficiently large viscosity before UV irradiation, and can well fix the precision wafer in the high-speed cutting process. After UV irradiation, its viscosity is small enough to facilitate automatic picking and achieve the superior effect of no residual glue on the bonded surface of the chip. The UV anti-viscosity tape provided by the present invention is a high-end UV anti-viscosity cutting tape that can be used for advanced semiconductor packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a schematic diagram of the process for preparing UV viscosity-reducing glue in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0025] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific implementation methods and are not intended to limit this application;

[0026] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific implementation methods and are not intended to limit this application;

[0027] The term "including" and its variations used in this article are open inclusions, that is, "including but not limited to"; the term "based on" is "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, the meaning of "multiple" is two or more.

[0028] like Figure 1 As shown, a method for preparing a UV viscosity-reducing glue provided by an embodiment of the present invention comprises:

[0029] Step S1: Under an inert gas protection atmosphere, subjecting the first mixture to a first polymerization reaction to obtain an acrylate main glue solution; wherein, the first mixture comprises, by weight: 20-90 parts of soft monomers, 0.5-40 parts of hard monomers, 0.5-20 parts of functional monomers, 0.5-1 parts of thermal initiators and 50-200 parts of organic solvents; preferably, by weight, the first mixture comprises: 50-85 parts of soft monomers, 5-20 parts of hard monomers, 1-10 parts of functional monomers, 0.5-1 parts of thermal initiators and 50-200 parts of organic solvents;

[0030] Step S2: adding a second mixture to the acrylate master glue solution to carry out a second step reaction to obtain a modified acrylate master glue solution; wherein the second mixture comprises, by weight: 2-10 parts of a modified monomer, 0.02-0.04 parts of a catalyst and 0.02-0.04 parts of an antioxidant; the modified monomer is a monomer containing an isocyanate group and two double bonds;

[0031] Step S3: adding a third mixture to the modified acrylate main glue solution, mixing evenly, to obtain a UV viscosity-reducing glue; wherein the third mixture comprises, by weight: 1-6 parts of a cross-linking agent and 1-6 parts of a photoinitiator;

[0032] Wherein, in step S2, the structural formula of the monomer containing an isocyanate group and two double bonds is as shown in formula (1):

[0033]

[0034] In formula (1), m and n are independently selected from integers of 1-10, and R is selected from one of a C1-C10 alkyl group, a phenyl group and a cyclohexyl group.

[0035] The embodiment of the present invention first obtains an acrylate main glue by a first step polymerization reaction; then, by a second step reaction, the acrylate main glue is modified by a monomer containing an isocyanate group and two double bonds, thereby introducing a high-density double bond into the acrylate main glue to obtain a modified acrylate main glue solution; finally, the modified acrylate main glue solution is mixed with a crosslinking agent and a photoinitiator to obtain a UV viscosity-reducing glue. The main component of the adhesive layer in the UV viscosity-reducing tape prepared by the UV viscosity-reducing glue is the modified acrylate main glue. During the viscosity-reducing process of UV irradiation treatment, the main chain in the modified acrylate main glue molecule is in a locked state, and the free movement of the molecule is limited. The high-density double bonds introduced into the molecule can effectively improve the crosslinking efficiency of the crosslinking reaction during the UV irradiation treatment, which is beneficial to improving the overall cohesive force of the adhesive layer in the UV viscosity-reducing tape, so that the UV viscosity-reducing tape after UV irradiation treatment has a sufficiently small viscosity. In addition, the main chain structure of the modified acrylate main glue molecule has soft and hard segments and functional monomers with strong polarity, which also makes the UV anti-viscosity tape before UV irradiation treatment have sufficient viscosity. In summary, the UV anti-viscosity tape prepared by the UV anti-viscosity glue prepared by the embodiment of the present invention has sufficient viscosity before UV irradiation, and can better fix the precision wafer in the high-speed cutting process. After UV irradiation, its viscosity is small enough to facilitate automatic picking and achieve the superior effect of no residual glue on the bonded surface of the chip.

[0036] In some embodiments of the present invention, in step S1, the temperature of the first step polymerization reaction is 60-90°C and the time is 8-14h; in step S2, the temperature of the second step reaction is 40-60°C and the time is 10-60min.

[0037] In some embodiments of the present invention, in the step S1, the first mixture further includes 0.1-10 parts of photosensitive comonomers. In this embodiment, the photoreactive groups are introduced into the modified acrylate main glue molecules through the photosensitive comonomers. During the viscosity reduction process of UV irradiation treatment, the main chain in the modified acrylate main glue molecules is in a locked state, and the free movement of the entire molecular chain is limited. The high-density double bonds introduced on the main chain can move locally, which can effectively improve the cross-linking efficiency of the cross-linking reaction during the UV irradiation treatment. The main chain of the modified acrylate main glue molecule has abundant hydrogen donors (such as hydroxyl, carboxyl and tertiary hydrogen on the side chain), which can dehydrogenate with the photoreactive groups. Under the above dual effects, it is easier to form a cross-linked structure, which can further improve the overall cohesion of the adhesive layer in the UV viscosity-reducing tape, so that the UV viscosity-reducing tape after UV irradiation treatment has a smaller viscosity. Preferably, in the step S1, the first mixture further includes 0.2-5 parts of photosensitive comonomers.

[0038] In some embodiments of the present invention, illustratively, the photosensitive comonomer includes at least one of acryloxybenzophenone, acryloxyethoxybenzophenone, and acryloxybutoxybenzophenone.

[0039] In some embodiments of the present invention, in step S2, the monomer containing an isocyanate group and two double bonds includes at least one of 1,1-bis(acryloyloxymethyl)ethyl isocyanate, 1,1-bis(acryloyloxyethyl)ethyl isocyanate and 1,2-bis(acryloyloxymethyl)cyclohexane isocyanate.

[0040] In some embodiments of the present invention, in step S1, the soft monomer includes at least one of (meth) alkyl acrylates with a branched or linear structure between C7 and C15, for example, the soft monomer includes at least one of butyl acrylate (BA), amyl acrylate, hexyl acrylate, heptyl acrylate, hexylethyl acrylate (EHA) and isooctyl acrylate (IOA); the hard monomer includes at least one of methyl methacrylate (MMA), ethyl acrylate (EA) and isobornyl acrylate (IBOA); the functional monomer includes at least one of acrylic acid (AA), methacrylic acid and hydroxyethyl acrylate (HEA); the thermal initiator includes at least one of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptonitrile and dibenzoyl peroxide; the organic solvent includes at least one of ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, benzene and toluene.

[0041] In some embodiments of the present invention, in step S2, the catalyst includes dibutyltin dilaurate, and the antioxidant includes one of a phenolic antioxidant, an amine antioxidant, and an organic phosphite antioxidant, for example, the antioxidant is p-methoxyphenol.

[0042] In some embodiments of the present invention, in step S3, the crosslinking agent includes at least one of a multifunctional isocyanate, a multifunctional aziridine, a high-valent metal acid ester and a metal chelate; the multifunctional isocyanate includes at least one of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI) and hexamethylene diisocyanate (HDI); the photoinitiator includes 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (photoinitiator TPO), 2,2-diisocyanate (HDI) and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (photoinitiator TPO). At least one of methoxy-2-phenylacetophenone (photoinitiator 651), 1-hydroxycyclohexyl phenyl ketone (photoinitiator 184), 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propanone (photoinitiator 261), 2-hydroxy-2-methyl-1-phenylpropan-1-one (photoinitiator 369), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (photoinitiator 819) and α-hydroxyketone (photoinitiator 907).

[0043] The embodiment of the present invention also provides a method for preparing a UV anti-viscosity tape, comprising:

[0044] Step M1: coating the UV viscosity-reducing glue as described above on the base film, and drying it to obtain a UV viscosity-reducing glue layer;

[0045] Step M2: affixing a release film on the surface of the UV anti-viscosity adhesive layer to obtain a UV anti-viscosity adhesive tape.

[0046] In some embodiments of the present invention, in step M1, the thickness of the base film is 50-200 μm, preferably, the thickness of the base film is 50-150 μm; the thickness of the UV anti-viscosity adhesive layer is 5-50 μm, preferably, the thickness of the UV anti-viscosity adhesive layer is 5-20 μm, and the material of the base film includes at least one of polypropylene, polyethylene, polyolefin, polyethylene glycol and polyvinyl chloride.

[0047] In some embodiments of the present invention, in step M1, the drying temperature is 60° C. and the drying time is 24 hours.

[0048] The present invention is further described below in conjunction with specific embodiments.

[0049] Example 1

[0050] A1: Under a nitrogen protective atmosphere, the first mixture is subjected to a first polymerization reaction to obtain an acrylate main glue solution; wherein the first mixture consists of 80 g EHA, 12 g MMA, 5 g AA, 3 g HEA, 0.5 g photosensitive comonomer, 0.5 g thermal initiator and 100 g ethyl acetate; the photosensitive comonomer is acryloxybenzophenone, and the thermal initiator is azobisisobutyronitrile; the temperature of the first polymerization reaction is 80°C and the time is 12 h.

[0051] A2: Add the second mixture to the acrylate main glue solution to carry out the second step reaction to obtain a modified acrylate main glue solution; wherein the second mixture consists of 5 grams of a modified monomer, 0.03 grams of dibutyltin dilaurate and 0.03 grams of p-methoxyphenol; the modified monomer is 1,1-di(acryloyloxymethyl)ethyl isocyanate; the temperature of the second step reaction is 50°C and the time is 15 minutes.

[0052] A3: Add the third mixture to the modified acrylate main glue solution and mix well to obtain UV viscosity-reducing glue; wherein the third mixture consists of 5 grams of toluene diisocyanate, 3 grams of photoinitiator TPO and 2 grams of photoinitiator 184.

[0053] A4: UV viscosity-reducing glue is coated on a polyolefin base film and dried to obtain a UV viscosity-reducing adhesive layer; the drying temperature is 60°C and the time is 24 hours; the thickness of the polyolefin base film is 100 μm, and the thickness of the UV viscosity-reducing adhesive layer is 10 μm.

[0054] A5: Paste a release film on the surface of the UV anti-adhesive layer to obtain a UV anti-adhesive tape.

[0055] Example 2

[0056] The difference from Example 1 is that in step A1, the first mixture does not contain a photosensitive comonomer.

[0057] Example 3

[0058] The difference from Example 1 is that in step A1, the first mixture consists of 60 g EHA, 20 g BA, 12 g MMA, 5 g AA, 3 g HEA, 0.5 g photosensitive comonomer, 0.5 g thermal initiator and 100 g ethyl acetate; the photosensitive comonomer is acryloxybenzophenone, and the thermal initiator is azobisisobutyronitrile.

[0059] Example 4

[0060] The difference from Example 1 is that in step A1, the first mixture consists of 60 g EHA, 20 g BA, 15 g MMA, 5 g AA, 0.5 g photosensitive comonomer, 0.5 g thermal initiator and 100 g ethyl acetate; the photosensitive comonomer is acryloxybenzophenone, and the thermal initiator is azobisisobutyronitrile.

[0061] Example 5

[0062] The difference from Example 1 is that in step A1, the first mixture consists of 60 g EHA, 20 g BA, 15 g MMA, 5 g HEA, 0.5 g photosensitive comonomer, 0.5 g thermal initiator and 100 g ethyl acetate; the photosensitive comonomer is acryloxybenzophenone, and the thermal initiator is azobisisobutyronitrile.

[0063] Example 6

[0064] The difference from Example 1 is that in step A2, the modified monomer is 1,1-bis(acryloyloxyethyl)ethyl isocyanate.

[0065] Comparative Example 1

[0066] B1: Under a nitrogen protective atmosphere, the first mixture is subjected to a first polymerization reaction to obtain an acrylate main glue solution; wherein the first mixture consists of 80 g EHA, 12 g MMA, 5 g AA, 3 g HEA, 0.5 g photosensitive comonomer, 0.5 g thermal initiator and 100 g ethyl acetate; the photosensitive comonomer is acryloxybenzophenone, and the thermal initiator is azobisisobutyronitrile; the temperature of the first polymerization reaction is 80°C and the time is 12 h.

[0067] B2: Add the third mixture to the acrylate main glue solution and mix well to obtain UV viscosity-reducing glue; wherein the third mixture consists of 5 grams of toluene diisocyanate, 3 grams of photoinitiator TPO and 2 grams of photoinitiator 184.

[0068] B3: UV viscosity-reducing glue is coated on a polyolefin base film and dried to obtain a UV viscosity-reducing adhesive layer; the drying temperature is 60° C. and the time is 24 hours; the thickness of the polyolefin base film is 100 μm, and the thickness of the UV viscosity-reducing adhesive layer is 10 μm.

[0069] B4: Paste a release film on the surface of the UV anti-adhesive layer to obtain a UV anti-adhesive tape.

[0070] Comparative Example 2

[0071] The difference from Example 1 is that in step A2, the modified monomer is 2-isocyanatoethyl acrylate, that is, an isocyanate-acrylate monomer having only one double bond.

[0072] Comparative Example 3

[0073] The difference from Comparative Example 1 is that in step B2, the third mixture consists of 5 g of toluene diisocyanate, 3 g of photoinitiator TPO, 2 g of photoinitiator 184 and 5 g of ethoxylated bisphenol A diacrylate resin.

[0074] Test results analysis

[0075] The 180° peeling force of the UV adhesive tapes prepared in Examples 1-6 and Comparative Examples 1-3 before and after UV irradiation was tested, and the results are shown in Table 1. It can be seen from Table 1 that the UV adhesive tapes prepared in Examples 1-6 and Comparative Examples 1-3 have higher 180° peeling force (above 6.0 N / 25 mm) before UV irradiation, and have higher viscosity; compared with Comparative Examples 1-3, the UV adhesive tapes prepared in Examples 1-6 have lower 180° peeling force (0.20 N / 2 5mm or less), the viscosity is significantly reduced, only a few tens or even one percent of that before UV irradiation; compared with Example 2, the UV viscosity-reducing tapes prepared in Example 1 and Examples 3-6 have relatively low 180° peel forces after UV irradiation, indicating that during UV irradiation, the dual effects of the monomer modification containing an isocyanate group and two double bonds and the photoreactive group can promote the formation of a denser cross-linked network between the material molecules, and the performance of the polymer bulk changes significantly, which is reflected in the viscosity, that is, the 180° peel force decreases more dramatically.

[0076] Wafer cutting was performed using the UV anti-adhesive tapes prepared in Examples 1-6 and Comparative Examples 1-3, and the proportion of chips successfully automatically picked up by the machine after cutting and the number of chips with residual glue were counted. The results are shown in Table 2. As can be seen from Table 2, compared with Comparative Examples 1-3, the proportion of successfully automatically picked up chips in Examples 1-6 is higher, both 100%, the number of chips with residual glue counted by optical microscope in Comparative Examples 1-3 are 6, 2 and 4, respectively, the number of chips with residual glue counted by optical microscope in Examples 1-6 is 0, the number of chips with residual glue counted by SEM-EDS in Comparative Examples 1-3 are 10, 5 and 9, respectively, the number of chips with residual glue counted by SEM-EDS in Example 2 is 2, and the number of chips with residual glue counted by SEM-EDS in Example 1 and Examples 3-6 is 0. It can be seen that compared with comparative examples 1-3, the use of the UV detackifying tapes in Examples 1-6 for wafer dicing can greatly reduce the possibility of residual adhesive on the bonded surface of the chip; and as mentioned above, the comparison between Example 1 and Example 2 shows that the formation of a more dense cross-linked structure helps to improve the overall cohesion of the material, so that the tape product has the good performance of completely no residual adhesive on the bonded surface of the chip after UV detackification.

[0077] Table 1

[0078]

[0079] Table 2

[0080]

[0081]

[0082] The adhesive tape performance testing method involved in the present invention is as follows:

[0083] 1) 180° peeling force test of adhesive tape: carried out in accordance with GB / T2792-2014 standard. The wavelength of UV light source used for UV irradiation is 365nm, and the light intensity is 500mJ / cm 2 .

[0084] 2) Automatic picking test: Use a blank silicon wafer for cutting, the cutting size is 0.75mm*0.75mm, and the wafer thickness is 100 microns; after cutting, use the automatic picking process of the machine to pick up, and pick up 100 chips in the center area of ​​each wafer.

[0085] The percentage of successfully automatically picked up chips = (the number of successfully picked up chips / 100) × 100%

[0086] 3) Randomly select 20 chips from the chips automatically picked up by the machine and use optical microscopy and SEM-EDS surface element scanning to perform residual adhesive detection. Samples with white or transparent residual adhesive observed under the optical microscope are counted into the residual adhesive quantity, and chips with obvious carbon enrichment and a large difference in element distribution from the wafer substrate under SEM-EDS scanning, and similar element distribution to the tape, are counted into the residual adhesive quantity.

[0087] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for preparing UV viscosity-reducing glue, characterized in that: include:: Step S1: Under an inert gas protection atmosphere, subjecting the first mixture to a first polymerization reaction to obtain an acrylate main glue solution; wherein, the first mixture comprises, by weight: 20-90 parts of soft monomers, 0.5-40 parts of hard monomers, 0.5-20 parts of functional monomers, 0.5-1 parts of thermal initiators and 50-200 parts of organic solvents; Step S2: adding a second mixture to the acrylate master glue solution to carry out a second step reaction to obtain a modified acrylate master glue solution; wherein the second mixture comprises, by weight: 2-10 parts of a modified monomer, 0.02-0.04 parts of a catalyst and 0.02-0.04 parts of an antioxidant; the modified monomer is a monomer containing an isocyanate group and two double bonds; Step S3: adding a third mixture to the modified acrylate main glue solution, mixing evenly, to obtain a UV viscosity-reducing glue; wherein, by weight, the third mixture comprises: 1-6 parts of a cross-linking agent and 1-6 parts of a photoinitiator; Wherein, in step S2, the structural formula of the monomer containing an isocyanate group and two double bonds is as shown in formula (1): In formula (1), m and n are independently selected from integers of 1-10, and R is selected from one of a C1-C10 alkyl group, a phenyl group and a cyclohexyl group.

2. The method for preparing UV viscosity-reducing glue according to claim 1, characterized in that: In the step S1, the first mixture further comprises 0.1-10 parts of a photosensitive comonomer.

3. The method for preparing UV viscosity-reducing glue according to claim 2, characterized in that: The photosensitive comonomer includes at least one of acryloxybenzophenone, acryloxyethoxybenzophenone, and acryloxybutoxybenzophenone.

4. The method for preparing UV viscosity-reducing glue according to claim 1, characterized in that: In the step S2, the monomer containing an isocyanate group and two double bonds includes at least one of 1,1-bis(acryloyloxymethyl)ethyl isocyanate, 1,1-bis(acryloyloxyethyl)ethyl isocyanate and 1,2-bis(acryloyloxymethyl)cyclohexane isocyanate.

5. The method for preparing UV viscosity-reducing glue according to claim 1, characterized in that: In the step S1, the soft monomer includes at least one of (meth) alkyl acrylates with a branched or linear structure between C7 and C15; the hard monomer includes at least one of methyl methacrylate, ethyl acrylate and isobornyl acrylate; the functional monomer includes at least one of acrylic acid, methacrylic acid and hydroxyethyl acrylate; the thermal initiator includes at least one of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptylonitrile and dibenzoyl peroxide; the organic solvent includes at least one of ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, benzene and toluene.

6. The method for preparing UV viscosity-reducing glue according to claim 1, characterized in that: In the step S2, the catalyst includes dibutyltin dilaurate, and the antioxidant includes at least one of a phenolic antioxidant, an amine antioxidant, and an organic phosphite antioxidant.

7. The method for preparing UV viscosity-reducing glue according to claim 1, characterized in that: In the step S3, the cross-linking agent includes at least one of a multifunctional isocyanate, a multifunctional aziridine, a high-valent metal acid ester and a metal chelate; the multifunctional isocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate and hexamethylene diisocyanate; the photoinitiator includes at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propanone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide and α-hydroxy ketone.

8. The method for preparing UV viscosity-reducing glue according to claim 1, characterized in that: In the step S1, the temperature of the first polymerization reaction is 60-90°C and the time is 8-14 hours; in the step S2, the temperature of the second polymerization reaction is 40-60°C and the time is 10-60 minutes.

9. A method for preparing a UV anti-viscosity tape, characterized in that: include: Step M1: coating the UV viscosity-reducing glue according to any one of claims 1 to 8 on the base film, and drying the same to obtain a UV viscosity-reducing glue layer; Step M2: affixing a release film on the surface of the UV anti-viscosity adhesive layer to obtain a UV anti-viscosity adhesive tape.

10. The method for preparing the UV anti-viscosity tape according to claim 9, characterized in that: In the step M1, the thickness of the base film is 50-200 μm, and the thickness of the UV anti-viscosity adhesive layer is 5-50 μm.

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