Preparation method for UV viscosity-reduction adhesive and preparation method for UV viscosity-reduction adhesive tape

Abstract

The present invention relates to the technical field of adhesive agents and provides a preparation method for a UV viscosity-reduction adhesive and a preparation method for a UV viscosity-reduction adhesive tape. In the present invention, first, a first polymerization reaction step is carried out to obtain an acrylate main adhesive; a second reaction step is then carried out to modify the acrylate main adhesive by means of a monomer containing an isocyanate group and two double bonds, that is, high-density double bonds are introduced into the acrylate main adhesive by means of a reaction between an active functional group on the main chain and the isocyanate group to obtain a modified acrylate main adhesive solution; and finally, the modified acrylate main adhesive solution is mixed with other additives, such as a cross-linking agent and a photoinitiator, to obtain the UV viscosity-reduction adhesive. The UV viscosity-reduction adhesive tape prepared using the UV viscosity-reduction adhesive prepared in the present invention has sufficiently high viscosity before UV irradiation and can secure a precise wafer during high-speed dicing; and after UV irradiation, the UV viscosity-reduction adhesive tape has sufficiently low viscosity to facilitate automatic pick-up, and a bonded surface of a chip is completely free of adhesive residue.

Description

Preparation method of UV debonding adhesive and UV debonding adhesive tape TECHNICAL FIELD

[0001] The present application relates to the technical field of adhesives, in particular to a preparation method of UV debonding adhesive and UV debonding adhesive tape. BACKGROUND

[0002] In recent years, the great progress made in the field of electronic devices and artificial intelligence is largely due to 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 higher requirements on wafer processing. In the wafer cutting process, the UV debonding adhesive tape needs to have better adhesion to fix the cut wafer; after wafer cutting is completed, the UV debonding adhesive tape will be irradiated with UV light before automatic picking to reduce its adhesion, thereby facilitating the separation of the UV debonding adhesive tape from the chip, and requiring no adhesive residue on the chip-adhesive surface. However, the existing UV debonding adhesive tape prepared by the UV debonding adhesive cannot simultaneously meet the above requirements, for example, the adhesion of the UV debonding adhesive tape before UV irradiation is not large enough, and the UV debonding adhesive tape cannot fix the cut wafer; the adhesion of the UV debonding adhesive tape after UV irradiation is still too large, which leads to automatic picking failure of the machine or cohesive damage of the adhesive residue on the chip-adhesive surface, causing serious impact on the appearance or subsequent electrical performance of the chip. SUMMARY

[0003] The problem solved by the present application is that the existing UV debonding adhesive tape prepared by the UV debonding adhesive cannot simultaneously meet the following requirements: before UV irradiation, the adhesion of the UV debonding adhesive tape is large enough, and the UV debonding adhesive tape can fix the cut wafer well; after UV irradiation, the adhesion of the UV debonding adhesive tape is small enough to facilitate automatic picking of the machine, while avoiding adhesive residue on the chip-adhesive surface.

[0004] To solve the above problems, the present application provides a preparation method of UV debonding adhesive, comprising:

[0005] Step S1: under the protection of an inert gas atmosphere, a first mixture is subjected to a first step of polymerization reaction to obtain an acrylate main adhesive solution; wherein, by weight fraction, the first mixture comprises: 20-90 parts of soft monomer, 0.5-40 parts of hard monomer, 0.5-20 parts of functional monomer, 0.5-1 part of thermal initiator, and 50-200 parts of organic solvent;

[0006] Step S2: adding a second mixture into the acrylate main glue solution to perform a second reaction, to obtain a modified acrylate main glue solution; wherein, the second mixture includes, in terms of weight fraction: 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 into the modified acrylate main glue solution and mixing uniformly to obtain a UV adhesion-reducing glue; wherein, the third mixture includes, in terms of weight fraction: 1-6 parts of a crosslinking agent, and 1-6 parts of a photoinitiator.

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

[0009] In formula (1), m and n are independently selected from integers of 1-10, and R is selected from one of C1-C10 alkyl, phenyl and cyclohexyl.

[0010] Optionally, in the step S1, the first mixture further includes 0.1-10 parts of a photosensitive comonomer.

[0011] Optionally, the photosensitive comonomer includes at least one of acryloxybenzophenone, acryloxyethoxybenzophenone and acryloxybutoxybenzophenone.

[0012] Optionally, in the step S2, the monomer containing an isocyanate group and two double bonds includes at least one of 1,1-di(acryloyloxymethyl)ethyl isocyanate, 1,1-di(acryloyloxyethyl)ethyl isocyanate and 1,2-di(acryloyloxymethyl)cyclohexane isocyanate.

[0013] Optionally, in the step S1, the soft monomer includes at least one of (meth)acrylic alkyl ester with a branched or straight chain structure between C7-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, azobisisopentyl nitrile, azobisisoheptyl nitrile and dibenzoyl peroxide; and the organic solvent includes at least one of ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, benzene and toluene.

[0014] Optionally, 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.

[0015] Optionally, in the step S3, the cross-linking agent comprises at least one of a multi-functional isocyanate, a multi-functional aziridine, a high-valent metal acid ester and a metal chelate; the multi-functional isocyanate comprises at least one of toluene diisocyanate, diphenyl methane diisocyanate and hexamethylene diisocyanate; the photoinitiator comprises at least one of 2,4,6-trimethylbenzoyl-diphenyl phosphine 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)-phenyl phosphine oxide and α-hydroxy ketone.

[0016] Optionally, in the step S1, the temperature of the first polymerization reaction is 60-90℃, and the time is 8-14h; in the step S2, the temperature of the second polymerization reaction is 40-60℃, and the time is 10-60min.

[0017] The application further provides a preparation method of the UV adhesion-reducing adhesive tape.

[0018] Step M1: coating the UV adhesion-reducing adhesive water as described above on a base film, and drying to obtain a UV adhesion-reducing adhesive layer;

[0019] Step M2: pasting a release film on the surface of the UV adhesion-reducing adhesive layer to obtain the UV adhesion-reducing adhesive tape.

[0020] Optionally, in the step M1, the thickness of the base film is 50-200μm, and the thickness of the UV adhesion-reducing adhesive layer is 5-50μm.

[0021] Compared with the prior art, the present application firstly obtains an acrylate main glue through a first step of polymerization reaction; then realizes the modification of the monomer containing an isocyanate group and two double bonds to the acrylate main glue through a second step of reaction, so as to introduce high-density double bonds into the acrylate main glue, and 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 adhesion-reducing adhesive. The main component of the glue layer of the UV adhesion-reducing adhesive tape prepared by using the UV adhesion-reducing adhesive is the modified acrylate main glue. In the adhesion-reducing process of UV irradiation treatment, the main chain of the modified acrylate main glue molecule is in a locked state, and the degree of free movement of the whole molecular chain is limited, while the high-density double bonds introduced on the main chain can move locally, which can effectively improve the crosslinking efficiency of the crosslinking reaction in the UV irradiation treatment process. In addition, 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 group. Under the above double effects, the crosslinking structure is more easily formed, and the overall cohesion of the glue layer of the UV adhesion-reducing adhesive tape is further improved, so that the UV adhesion-reducing adhesive tape after UV irradiation treatment has smaller adhesion. In addition, the main chain structure of the modified acrylate main glue molecule has soft and hard segments and a functional monomer with strong polarity, which also makes the UV adhesion-reducing adhesive tape before UV irradiation treatment have a large enough adhesion. In summary, the UV adhesion-reducing adhesive tape prepared by using the UV adhesion-reducing adhesive of the present application has a large enough adhesion before UV irradiation, which can better fix the precision wafer in the high-speed cutting process, and has a small enough adhesion after UV irradiation, which is convenient for automatic picking and can achieve the superior effect of completely no residue glue on the chip adhered surface. The UV adhesion-reducing adhesive tape provided by the present application belongs to a high-end UV adhesion-reducing cutting adhesive tape that can be used for advanced packaging of semiconductors. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a flow diagram of the preparation method of the UV adhesion-reducing adhesive of the embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings. Although some embodiments of the present application are shown in the drawings, it should be understood that the present application 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 make the present application more thorough and complete. It should be understood that the drawings and embodiments of the present application are only for illustrative purposes, and are not intended to limit the scope of protection of the present application.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application.

[0026] The term "comprising" and variations thereof as used herein are used inclusively, i.e., "comprising but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments." Related definitions are given throughout the description below. It is to be noted that the terms "first", "second", and the like, as used herein do not denote any order, quantity, combination or importance, but rather are used to nomenclature different objects. Also, the terms "first", "second", etc. are used only for the purpose of description and are not to be construed as indicating or implying those indicated technical features are essential or indispensable. Thus, the features with "first", "second" can include one or more of the features. In the description of the application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0027] As shown in FIG. 1, the application provides a preparation method of UV adhesion-reducing glue, comprising:

[0028] Step S1: under the protection of inert gas atmosphere, a first mixture is subjected to a first step polymerization reaction to obtain an acrylate main glue solution; wherein, the first mixture comprises, by weight fraction, 20-90 parts of soft monomer, 0.5-40 parts of hard monomer, 0.5-20 parts of functional monomer, 0.5-1 part of thermal initiator and 50-200 parts of organic solvent; preferably, the first mixture comprises, by weight fraction, 50-85 parts of soft monomer, 5-20 parts of hard monomer, 1-10 parts of functional monomer, 0.5-1 part of thermal initiator and 50-200 parts of organic solvent;

[0029] Step S2: adding a second mixture into the acrylate main glue solution to perform a second step reaction to obtain a modified acrylate main glue solution; wherein, the second mixture includes, by weight fraction: 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;

[0030] Step S3: adding a third mixture into the modified acrylate main glue solution and mixing uniformly to obtain a UV adhesion-reducing glue; wherein, the third mixture includes, by weight fraction: 1-6 parts of a crosslinking agent, and 1-6 parts of a photoinitiator;

[0031] In the step S2, the monomer containing an isocyanate group and two double bonds has a structure as shown in formula (1):

[0032] In formula (1), m and n are independently selected from integers of 1-10, and R is selected from one of C1-C10 alkyl, phenyl and cyclohexyl.

[0033] The UV adhesion-reducing glue prepared by the embodiment of the present application has the following advantages: the main component of the glue layer of the UV adhesion-reducing tape prepared by the UV adhesion-reducing glue is the modified acrylate main glue, in the UV irradiation treatment process of adhesion reduction, the main chain of the modified acrylate main glue molecule is in a locked state and the degree of free movement of the molecule is limited, while the high-density double bonds introduced into the molecule can effectively improve the crosslinking efficiency of the crosslinking reaction in the UV irradiation treatment process, which is conducive to improving the overall cohesion of the glue layer of the UV adhesion-reducing tape, so that the UV adhesion-reducing tape after UV irradiation treatment has a small enough adhesion. In addition, the main chain structure of the modified acrylate main glue molecule has soft and hard segments and a functional monomer with strong polarity, which also makes the UV adhesion-reducing tape before UV irradiation treatment have a large enough adhesion. In summary, the UV adhesion-reducing tape prepared by the UV adhesion-reducing glue prepared by the embodiment of the present application has a large enough adhesion before UV irradiation, which can better fix the precision wafer in the high-speed cutting process, and has a small enough adhesion after UV irradiation, which is convenient for automatic picking and achieves the superior effect of completely no residual glue on the chip adhered surface.

[0034] In some embodiments of the present application, in the step S1, the temperature of the first step polymerization reaction is 60-90℃, and the time is 8-14h; in the step S2, the temperature of the second step reaction is 40-60℃, and the time is 10-60min.

[0035] In some embodiments of the present application, the first mixture in step S1 further comprises 0.1-10 parts of a photosensitive comonomer. In this embodiment, the photosensitive comonomer is used to introduce the photoreactive group into the modified acrylate main glue molecule. During the UV irradiation treatment for viscosity reduction, the main chain of the modified acrylate main glue molecule is in a locked state, and the degree of free movement of the entire molecular chain is limited. However, 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. In addition, 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, which can further improve the overall cohesion of the glue layer in the UV viscosity-reducing adhesive tape, so that the UV viscosity-reducing adhesive tape after UV irradiation treatment has smaller viscosity. Preferably, the first mixture in step S1 further comprises 0.2-5 parts of a photosensitive comonomer.

[0036] In some embodiments of the present application, the photosensitive comonomer includes at least one of acryloyloxybenzophenone, acryloyloxyethoxybenzophenone, and acryloyloxybutoxybenzophenone.

[0037] In some embodiments of the present application, the monomer containing an isocyanate group and two double bonds in step S2 includes at least one of 1,1-di(acryloyloxymethyl)ethyl isocyanate, 1,1-di(acryloyloxyethyl)ethyl isocyanate, and 1,2-di(acryloyloxymethyl)cyclohexane isocyanate.

[0038] In some embodiments of the present application, the soft monomer in step S1 includes at least one of (meth)acrylic acid alkyl ester with branched or straight chain structure between C7-C15, such as at least one of butyl acrylate (BA), pentyl acrylate, hexyl acrylate, heptyl acrylate, hexyl ethyl 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, azobisisopentyl nitrile, azobisisoheptyl nitrile, and dibenzoyl peroxide; and the organic solvent includes at least one of ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, benzene, and toluene.

[0039] In some embodiments of the present application, in the step S2, the catalyst comprises dibutyltin dilaurate, the antioxidant comprises one of phenolic antioxidant, amine antioxidant and organic phosphite antioxidant, for example, the antioxidant is p-methoxyphenol.

[0040] In some embodiments of the present application, in the step S3, the crosslinking agent comprises at least one of polyfunctional isocyanate, polyfunctional aziridine, permetalate and metal chelate; the polyfunctional isocyanate comprises at least one of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI) and hexamethylene diisocyanate (HDI); the photoinitiator comprises at least one of 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide (photoinitiator TPO), 2,2-dimethoxy-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)-phenyl phosphine oxide (photoinitiator 819) and α-hydroxy ketone (photoinitiator 907).

[0041] The present application also provides a preparation method of the UV adhesion-reducing adhesive tape, comprising:

[0042] Step M1: applying the UV adhesion-reducing adhesive water as described above on the base film, and drying to obtain a UV adhesion-reducing adhesive layer;

[0043] Step M2: pasting a release film on the surface of the UV adhesion-reducing adhesive layer to obtain the UV adhesion-reducing adhesive tape.

[0044] In some embodiments of the present application, in the 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 adhesion-reducing adhesive layer is 5-50 μm, preferably, the thickness of the UV adhesion-reducing adhesive layer is 5-20 μm; the material of the base film comprises at least one of polypropylene, polyethylene, polyolefin, poly-p-xylylene glycol and polyvinyl chloride.

[0045] In some embodiments of the present application, in the step M1, the drying temperature is 60℃ and the drying time is 24 h.

[0046] The present application is further described below in conjunction with specific embodiments.

[0047] Embodiment 1

[0048] A1: The first mixture is subjected to a first step of polymerization reaction under a nitrogen protective atmosphere to obtain an acrylate main adhesive solution; wherein the first mixture is composed of 80 grams of EHA, 12 grams of MMA, 5 grams of AA, 3 grams of HEA, 0.5 grams of a photosensitive comonomer, 0.5 grams of a thermal initiator and 100g of ethyl acetate; the photosensitive comonomer is acryloxybenzophenone, and the thermal initiator is azobisisobutyronitrile; the temperature of the first step of polymerization reaction is 80°C, and the time is 12h.

[0049] A2: A second mixture is added to the acrylate main adhesive solution to perform a second step of reaction to obtain a modified acrylate main adhesive solution; wherein the second mixture is composed of 5 grams of a modification monomer, 0.03 grams of dibutyltin dilaurate and 0.03 grams of p-methoxyphenol; the modification monomer is 1,1-di(acryloyloxymethyl)ethyl isocyanate; the temperature of the second step of reaction is 50°C, and the time is 15min.

[0050] A3: A third mixture is added to the modified acrylate main adhesive solution to mix uniformly to obtain a UV adhesion-reducing adhesive; wherein the third mixture is composed of 5 grams of toluene diisocyanate, 3 grams of a photoinitiator TPO and 2 grams of a photoinitiator 184.

[0051] A4: The UV adhesion-reducing adhesive is coated on a polyolefin-based film to perform drying treatment to obtain a UV adhesion-reducing adhesive layer; the temperature of the drying treatment is 60°C, and the time is 24h; the thickness of the polyolefin-based film is 100μm, and the thickness of the UV adhesion-reducing adhesive layer is 10μm.

[0052] A5: A release film is pasted on the surface of the UV adhesion-reducing adhesive layer to obtain a UV adhesion-reducing adhesive tape.

[0053] Example 2

[0054] The difference from Example 1 is that in step A1, the first mixture does not contain a photosensitive comonomer.

[0055] Example 3

[0056] The difference from Example 1 is that in step A1, the first mixture is composed of 60 grams of EHA, 20 grams of BA, 12 grams of MMA, 5 grams of AA, 3 grams of HEA, 0.5 grams of a photosensitive comonomer, 0.5 grams of a thermal initiator and 100g of ethyl acetate; the photosensitive comonomer is acryloxybenzophenone, and the thermal initiator is azobisisobutyronitrile.

[0057] Example 4

[0058] The difference from Example 1 is that in step A1, the first mixture is composed of 60 grams of EHA, 20 grams of BA, 15 grams of MMA, 5 grams of AA, 0.5 grams of photosensitive comonomer, 0.5 grams of thermal initiator, and 100g of ethyl acetate; the photosensitive comonomer is acryloyloxybenzophenone, and the thermal initiator is azobisisobutyronitrile.

[0059] Example 5

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

[0061] Example 6

[0062] The difference from Example 1 is that in step A2, the modifying monomer is 1,1-di(acryloyloxyethyl)ethyl isocyanate.

[0063] Comparative Example 1

[0064] B1: The first mixture is subjected to a first-step polymerization reaction under a nitrogen protective atmosphere to obtain an acrylate main adhesive solution; wherein the first mixture is composed of 80 grams of EHA, 12 grams of MMA, 5 grams of AA, 3 grams of HEA, 0.5 grams of photosensitive comonomer, 0.5 grams of thermal initiator, and 100g of ethyl acetate; the photosensitive comonomer is acryloyloxybenzophenone, and the thermal initiator is azobisisobutyronitrile; the temperature of the first-step polymerization reaction is 80°C, and the time is 12h.

[0065] B2: A third mixture is added to the acrylate main adhesive solution and mixed uniformly to obtain a UV adhesion-reducing adhesive; wherein the third mixture is composed of 5 grams of toluene diisocyanate, 3 grams of photoinitiator TPO, and 2 grams of photoinitiator 184.

[0066] B3: The UV adhesion-reducing adhesive is coated on a polyolefin-based film and subjected to drying treatment to obtain a UV adhesion-reducing adhesive layer; the temperature of the drying treatment is 60°C, and the time is 24h; the thickness of the polyolefin-based film is 100μm, and the thickness of the UV adhesion-reducing adhesive layer is 10μm.

[0067] B4: A release film is pasted on the surface of the UV adhesion-reducing adhesive layer to obtain a UV adhesion-reducing adhesive tape.

[0068] Comparative Example 2

[0069] The difference from Example 1 is that in step A2, the modifying monomer is 2-isocyanatoethyl acrylate, that is, an isocyanate-acrylate monomer with only one double bond.

[0070] Comparative Example 3

[0071] The difference from Comparative Example 1 is that in step B2, the third mixture is composed of 5 grams of toluene diisocyanate, 3 grams of photoinitiator TPO, 2 grams of photoinitiator 184 and 5 grams of ethoxylated bisphenol A diacrylate resin.

[0072] Test result analysis

[0073] The 180° peeling forces of the UV debonding adhesive tapes prepared in Examples 1-6 and Comparative Examples 1-3 before and after UV irradiation were tested, and the results are shown in Table 1. As can be seen from Table 1, the UV debonding adhesive tapes prepared in Examples 1-6 and Comparative Examples 1-3 all have high 180° peeling forces (above 6.0 N / 25 mm) before UV irradiation, and have high adhesion. Compared with Comparative Examples 1-3, the UV debonding adhesive tapes prepared in Examples 1-6 all have low 180° peeling forces (below 0.20 N / 25 mm) after UV irradiation, and the adhesion is reduced significantly, only tens or even hundreds of percent of the adhesion before UV irradiation. Compared with Example 2, the UV debonding adhesive tapes prepared in Examples 1 and 3-6 all have relatively low 180° peeling forces after UV irradiation, which indicates that the dual effects of the modification of the monomer containing isocyanate groups and two double bonds and the photoreaction group can promote the formation of a more dense crosslinked network between the molecules of the material during the UV irradiation process, and the properties of the polymer bulk change significantly, which is reflected in the adhesion, i.e., the 180° peeling force decreases more severely.

[0074] The wafer cutting was performed using the UV debonding adhesive tapes prepared in Examples 1-6 and Comparative Examples 1-3, and the proportion of the chips successfully picked up automatically by the machine after cutting and the number of chips with residual glue were counted, and the results are shown in Table 2. As can be seen from Table 2, compared with Comparative Examples 1-3, the proportion of the chips successfully picked up automatically by the machine is higher in Examples 1-6, all being 100%, the number of chips with residual glue counted by optical microscopy is 6, 2 and 4 respectively in Comparative Examples 1-3, the number of chips with residual glue counted by optical microscopy is 0 in Examples 1-6, the number of chips with residual glue counted by SEM-EDS is 10, 5 and 9 respectively in Comparative Examples 1-3, the number of chips with residual glue counted by SEM-EDS is 2 in Example 2, and the number of chips with residual glue counted by SEM-EDS is 0 in Examples 1 and 3-6. It can be seen that compared with Comparative Examples 1-3, wafer cutting using the UV debonding adhesive tapes in Examples 1-6 can greatly reduce the possibility of residual glue on the chip bonding surface; and as described above, the comparison between Example 1 and Example 2 indicates that the formation of a more dense crosslinked structure helps to improve the overall cohesion of the material, so that the adhesive tape product has the good performance of completely no residual glue on the chip bonding surface after UV debonding.

[0075] Table 1

[0076] Table 2

[0077] The tape performance test method involved in the present application is as follows:

[0078] 1) Tape 180° peeling force test: according to GB / T2792-2014 standard. The wavelength of the UV light source used for UV irradiation is 365 nm, and the light intensity is 500 mJ / cm2.

[0079] 2) Automatic picking test on the machine: a piece of silicon blank wafer is used for cutting, and the cutting size is 0.75 mm*0.75 mm, and the wafer thickness is 100 microns; after cutting, the picking is carried out by the machine automatic picking process, and 100 chips are picked in the center area of each wafer.

[0080] Successful automatic picking chip ratio = (the number of successfully picked chips / 100) x 100%

[0081] 3) 20 chips randomly selected from the chips picked on the machine are used for residue detection by optical microscope and SEM-EDS surface element scanning, respectively. The samples with white or transparent residue observed under the optical microscope are counted into the residue number, and the chips with obvious carbon element enrichment and too large difference in element distribution with the wafer substrate and similar element distribution with the tape are counted into the residue number.

[0082] Although the present application is disclosed as above, the protection scope of the present application is not limited to this. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and these changes and modifications will fall within the protection scope of the present application.

Claims

1. A method for preparing a UV-debondable adhesive, characterized by, The application relates to a UV debonding adhesive solution and a preparation method thereof. Step S1: a first mixture is subjected to a first polymerization reaction under an inert gas protection atmosphere to obtain an acrylate main glue solution; wherein the first mixture comprises, in terms of weight fractions, 20-90 parts of soft monomers, 0.5-40 parts of hard monomers, 0.5-20 parts of functional monomers, 0.5-1 part of a thermal initiator and 50-200 parts of an organic solvent; Step S2: a second mixture is added to the acrylate main glue solution to perform a second reaction, so as to obtain a modified acrylate main glue solution; wherein the second mixture comprises, in terms of weight fractions, 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: a third mixture is added to the modified acrylate main glue solution and uniformly mixed to obtain the UV debonding adhesive solution; wherein the third mixture comprises, in terms of weight fractions, 1-6 parts of a crosslinking agent and 1-6 parts of a photoinitiator. In step S2, the monomer containing an isocyanate group and two double bonds has a structural formula 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 C1-C10 alkyl, phenyl and cyclohexyl.

2. The method of claim 1, wherein the UV debonding adhesive is prepared by mixing the UV curable adhesive and the photodegradable compound in a weight ratio of 1 : 0.1 to 1 :

10. In the step S1, the first mixture further comprises 0.1-10 parts of a photosensitive comonomer.

3. The method of claim 2, wherein the UV debonding adhesive is prepared by mixing the UV curable adhesive and the photoinitiator in a weight ratio of 1 : 0.1 to 1 : 0.

5. The photosensitive comonomer comprises at least one of acryloyloxybenzophenone, acryloyloxyethoxybenzophenone and acryloyloxybutoxybenzophenone.

4. The method of claim 1, wherein the UV debonding adhesive is prepared by mixing the UV curable adhesive and the photoinitiator in a weight ratio of 1:0.1 to 1:0.

5. In the step S2, the monomer containing an isocyanate group and two double bonds comprises at least one of 1,1-di(acryloyloxymethyl)ethyl isocyanate, 1,1-di(acryloyloxyethyl)ethyl isocyanate and 1,2-di(acryloyloxymethyl)cyclohexane isocyanate.

5. The method of claim 1, wherein the UV debonding adhesive is prepared by mixing the UV curable adhesive and the photoinitiator in a weight ratio of 1:0.1 to 1:0.

5. In the step S1, the soft monomer comprises at least one of (meth)acrylic alkyl esters with branched or straight chain structures between C7 and C15; the hard monomer comprises at least one of methyl methacrylate, ethyl acrylate and isobornyl acrylate; the functional monomer comprises at least one of acrylic acid, methacrylic acid and hydroxyethyl acrylate; the thermal initiator comprises at least one of azobisisobutyronitrile, azobisisopentyl nitrile, azobisisoheptyl nitrile and dibenzoyl peroxide; and the organic solvent comprises at least one of ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, benzene and toluene.

6. The method of claim 1, wherein the UV debonding adhesive is prepared by mixing the UV curable adhesive and the photoinitiator in a weight ratio of 1:0.1 to 1:0.

5. In the step S2, the catalyst comprises dibutyltin dilaurate, and the antioxidant comprises at least one of phenolic antioxidants, amine antioxidants and phosphite antioxidants.

7. The method of claim 1, wherein the UV debonding adhesive is prepared by mixing the UV curable adhesive and the photoinitiator in a weight ratio of 1:0.1 to 1:0.

5. The cross-linking agent in the step S3 comprises at least one of a multi-functional isocyanate, a multi-functional aziridine, a high-valent metal acid ester and a metal chelate; the multi-functional isocyanate comprises at least one of toluene diisocyanate, diphenyl methane diisocyanate and hexamethylene diisocyanate; and the photoinitiator comprises at least one of 2,4,6-trimethylbenzoyl-diphenyl phosphine 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)-phenyl phosphine oxide and α-hydroxy ketone.

8. The method for preparing the UV anti-tack adhesive according to claim 1, characterized in that, In the step S1, the temperature of the first polymerization reaction is 60-90℃, and the time is 8-14h; and in the step S2, the temperature of the second polymerization reaction is 40-60℃, and the time is 10-60min.

9. A method for producing a UV-debondable adhesive tape, characterized by, Comprise: Step M1: applying the UV debonding glue in any one of claims 1-8 on a base film, drying treatment to obtain a UV debonding glue layer; Step M2: pasting a release film on the surface of the UV debonding glue layer to obtain a UV debonding adhesive tape.

10. The method of producing a UV-debondable tape according to claim 9, wherein In the step M1, the thickness of the base film is 50-200μm, and the thickness of the UV debonding glue layer is 5-50μm.

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