Adhesive tape

Abstract

In this field, there is a need to improve the performance of light-irradiation peelable dicing tapes. [Solution] This disclosure provides an adhesive tape comprising a substrate and an adhesive composition disposed on the substrate. The adhesive composition comprises an acrylic resin, a crosslinking agent, and a Norish type I photoinitiator. After curing by irradiation with ultraviolet light at a wavelength of 365 nm, approximately 36 mm 3 An adhesive composition having the specified volume yields a fragment content of less than 10 ppm of Norish type I photoinitiator when measured by gas chromatography-mass spectrometry (GC-MS) in a 20 mL sealed space under standard conditions.

Description

[Technical Field]

[0001] This application claims priority to Taiwan Patent Application No. 113143629, “Adhesive Tape,” filed with the Taiwan Intellectual Property Office on November 13, 2024, pursuant to Section 119(a) of the United States Patent Act. All disclosures of said application are incorporated herein by reference.

[0002] This disclosure relates to adhesive tapes. This disclosure relates to adhesive tapes comprising adhesive compositions, and more particularly to light-irradiation peelable dicing tapes in semiconductor processes. [Background technology]

[0003] Light-irradiated dicing tape is used to hold semiconductor wafers in place during the dicing / separation process. Before light irradiation, the tape has strong adhesive properties, and no problems with movement or peeling can occur. After light irradiation, the adhesive properties decrease, making the tape easily removable and avoiding mechanical damage to the product caused by the tape's adhesion. [Overview of the project] [Problems that the invention aims to solve]

[0004] In this field, there is a need to improve the performance of light-irradiation peelable dicing tapes. [Means for solving the problem]

[0005] This disclosure provides a novel adhesive tape comprising a substrate and an adhesive composition disposed on the substrate. The adhesive composition comprises an acrylic resin, a crosslinking agent, and a Norish type I photoinitiator. After curing by UV irradiation at a wavelength of 365 nm, approximately 36 mm 3 An adhesive composition having the specified volume yields a fragment content of less than 10 ppm of Norish type I photoinitiator when measured by gas chromatography-mass spectrometry (GC-MS) in a 20 mL sealed space under standard conditions. [Modes for carrying out the invention]

[0006] To facilitate understanding of the information disclosed herein, several terms are defined below.

[0007] Within the scope of this specification and this patent application, all numerical values ​​used to express content, proportion, physical properties, etc., should be understood to be modified in all cases by the terms “approximately” or “about.” As used herein, the terms “approximately” or “about” mean a tolerance in a particular value as determined by a person skilled in the art, although this depends in part on the method of measuring or determining the value.

[0008] In this specification, unless otherwise specified, the singular forms "a," "an," and "the" include their plural forms. Any embodiments and exemplary terms ("for example" and "etc.") used herein are intended solely to highlight the disclosure and not to constitute a limitation on the scope of the disclosure. The terms used herein should not be construed as suggesting that methods and conditions not claimed may constitute essential features in the practice of the disclosure.

[0009] The word "or" in a list of two or more items encompasses any of the following interpretations: any one item in the list, all items in the list, and any combination of items in the list.

[0010] All ranges disclosed herein should be understood to encompass all subranges contained therein. For example, the range "1 to 10" is considered to include all subranges between the minimum value 1 and the maximum value 10, and to include the minimum value 1 and the maximum value 10. That is, it is considered to include all subranges that begin with a minimum value of 1 or greater than 1 and end with a maximum value of 10 or less than 10, such as the ranges 1 to 6.7, 3.2 to 8.1, or 5.5 to 10, and any number within this range, such as 2.6, 4.7, or 7.3.

[0011] The performance of the photo-irradiated peelable dicing tape in this disclosure has at least two requirements: (1) The tape must be able to securely fix the wafer during the dicing process. (2) The tape must be able to be easily peeled off the wafer after photoirradiation. The above requirements can be achieved by using a photo-irradiated adhesive composition. This adhesive composition hardens, forms, and solidifies after photoirradiation, causing the tape to lose its adhesive strength (i.e., peel off). However, during the curing process of the adhesive composition by photoirradiation, the photoinitiator contained in the adhesive composition decomposes, releasing gaseous photoinitiator fragments (hereinafter referred to as "photoinitiator fragments"), and outgassing of the adhesive composition occurs, contaminating the wafer. This is undesirable for the stability of the semiconductor process and the reliability of the final device. Furthermore, since photoinitiator fragments may also be released during wafer cleaning, the photoinitiator fragments disperse in the solvent (e.g., an aqueous solution of tetramethylammonium hydroxide (TMAH) or NH4OH) and consequently remain on the wafer.

[0012] To achieve the above objectives, this disclosure provides an adhesive tape comprising a substrate and an adhesive composition described herein disposed on the substrate. The adhesive tape is preferably a photo-irradiation peelable dicing tape in semiconductor processes. This disclosure further provides an adhesive composition comprising an acrylic resin, a crosslinking agent, and a photoinitiator.

[0013] The contents of this disclosure are described in detail below. Acrylic resin component of adhesive composition

[0014] The adhesive composition of this disclosure is mainly based on acrylic resin. Compared to other resins, acrylic resin can offer many superior properties. For example, acrylic resin has high adhesive strength before ultraviolet (UV) irradiation, so it can reliably adhere to various substrates. However, after UV irradiation, the polymer chains in the acrylic resin bond together to form a three-dimensional mesh structure, causing the adhesive strength to decrease rapidly, and the tape can be easily and cleanly removed. Furthermore, because acrylic resin exhibits extremely low adhesive strength after UV irradiation, there is no residual adhesive on the substrate, and the surface can be kept clean. Acrylic resin reacts to UV irradiation in a very short time, which can effectively improve work efficiency.

[0015] A suitable acrylic resin may contain one or more repeating units derived from acrylic or acrylate monomers. The repeating units may have residues of acrylic monomers containing a radiation-curable carbon-carbon double bond group.

[0016] The acrylic resin may be a homopolymer or a copolymer. The monomers forming the acrylic resin may include one or more first monomers and one or more second monomers different from the first monomers. The first monomers are selected from the group consisting of alkyl esters of (meth)acrylic acid, cycloalkyl esters of (meth)acrylic acid, and aryl esters of (meth)acrylic acid. The first monomers may be copolymerized with the second monomers to form an acrylic resin in order to provide desired properties such as bonding strength and peel strength.

[0017] Suitable alkyl esters of (meth)acrylic acid include, for example, C1-C of (meth)acrylic acid. 20Alkyl esters, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl This includes, but is not limited to, syl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, or octadecyl (meth)acrylate.

[0018] Suitable cycloalkyl esters of (meth)acrylic acid include, for example, C3-C of (meth)acrylic acid. 20 Cycloalkyl esters, such as cyclopropyl (meth)acrylate, cyclobutyl (meth)acrylate, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, cyclooctyl (meth)acrylate, cyclononyl (meth)acrylate, cyclodecyl (meth)acrylate, cycloundecyl (meth)acrylate, cyclododecyl (meth)acrylate, cyclotridecyl (meth)acrylate, cyclotetradecyl (meth)acrylate, cyclopentadecyl (meth)acrylate, cyclohexadecyl (meth)acrylate, cycloheptadecyl (meth)acrylate, or cyclooctadecyl (meth)acrylate, are included but are not limited to these.

[0019] Suitable aryl esters of (meth)acrylic acid include, for example, C6-C of (meth)acrylic acid. 12Aryl esters, such as phenyl (meth)acrylate, are included, but not limited thereto.

[0020] The first monomer is preferably an alkyl ester of (meth)acrylic acid, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate or isooctyl (meth)acrylate.

[0021] The second monomer is based on, for example, but not limited to, the following monomers: carboxy-containing monomers, anhydride-containing monomers, hydroxy-containing monomers, sulfonate-containing monomers, phosphate-containing monomers, amide monomers, cyano-containing monomers, amino-containing monomers, epoxy-containing monomers, alkenyl monomers, styrene monomers, vinyl ester monomers, vinyl ether monomers, isocyanate-containing monomers, monomers having a ring containing one or more nitrogen atoms. In some embodiments, the second monomer may include a combination of the following: carboxy-containing monomers, hydroxy-containing monomers and isocyanate-containing monomers.

[0022] Suitable carboxy-containing monomers include, for example, (meth)acrylic acid, 2-carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, cis-butenedioic acid, trans-butenedioic acid, crotonic acid or isocrotonic acid, but are not limited thereto.

[0023] Suitable anhydride-containing monomers include, for example, maleic anhydride or itaconic anhydride, but are not limited thereto.

[0024] Suitable hydroxyl-containing monomers include, but are not limited to, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxypropyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-(hydroxymethyl)cyclohexyl)methyl (meth)acrylate, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, ethylene glycol monovinyl ether, diethylene glycol monovinyl ether, propylene glycol monovinyl ether, or dipropylene glycol monovinyl ether.

[0025] Suitable sulfonate-containing monomers include, but are not limited to, styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, or (meth)acryloyloxynaphthalenesulfonic acid.

[0026] Suitable phosphate-containing monomers include, but are not limited to, 2-hydroxyethyl acryloyl phosphate.

[0027] Suitable amide monomers include, but are not limited to, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxymethylpropyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, or N-butoxymethyl(meth)acrylamide.

[0028] Suitable cyano-containing monomers include, but are not limited to, (meth)acrylonitrile.

[0029] Suitable amino acid-containing monomers include, but are not limited to, ethylamine (meth)acrylate, ethyl N,N-dimethylamine (meth)acrylate, or ethyl tert-butylamine (meth)acrylate.

[0030] Suitable epoxy-containing monomers include, but are not limited to, glycidyl (meth)acrylate or methylglycidyl (meth)acrylate.

[0031] Suitable alkenyl monomers include, but are not limited to, ethylene, propylene, isopropylene, butadiene, or isobutylene.

[0032] Suitable styrene monomers include, but are not limited to, styrene, α-methylstyrene, or vinyltoluene.

[0033] Suitable vinyl ester monomers include, but are not limited to, vinyl acetate or vinyl propionate.

[0034] Suitable vinyl ether monomers include, but are not limited to, methyl vinyl ether or ethyl vinyl ether.

[0035] Suitable isocyanate-containing monomers include, for example, (meth)acryloyl isocyanate, (meth)acryloyloxymethyl isocyanate, 2-(meth)acryloyloxyethyl isocyanate, 2-(meth)acryloyloxypropyl isocyanate, 3-(meth)acryloyloxypropyl isocyanate, 4-(meth)acryloyloxybutyl isocyanate, or m-propenyl-α,α-dimethylbenzyl isocyanate, preferably 2-(meth)acryloyloxyethyl isocyanate, but are not limited to these, and impart improved heat resistance and peel resistance to the resulting acrylic resin.

[0036] Suitable monomers having a ring containing one or more nitrogen atoms include, but are not limited to, N-vinyl-2-pyrrolidinone, N-methylvinylpyrrolidinone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinylazole, N-vinylquinoline, N-vinylcaprolactam, or N-(meth)acryloylmorpholine.

[0037] In some embodiments, the second monomer may include a combination of acrylic acid, 2-hydroxyethyl acrylate, and 2-methacryloyloxyethyl isocyanate, and the resulting acrylic resin can exhibit good adhesion before light curing.

[0038] The amount of the first monomer is not particularly limited and can be adjusted according to the actual application requirements. In some embodiments, the amount (percentage) of the first monomer relative to the total amount of monomers in the acrylic resin may be about 40% by mass to about 80% by mass, for example, about 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80% by mass, and preferably about 60% to about 70% by mass.

[0039] The amount of the second monomer is not particularly limited and can be adjusted according to the actual application requirements. In some embodiments, the amount (percentage) of the second monomer relative to the total amount of monomers in the acrylic resin may be about 20% by mass to about 60% by mass, for example, about 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, or 60% by mass, and preferably about 30% to about 40% by mass.

[0040] In the second monomer, the amount of carboxyl-containing monomer is not particularly limited and can be adjusted according to the actual application requirements. In some embodiments, the amount (percentage) of carboxyl-containing monomer relative to the total amount of monomers in the acrylic resin may be about 0.1% by mass to about 10% by mass, for example, about 0.1% by mass, 0.5% by mass, 1% by mass, 2% by mass, 3% by mass, 4% by mass, 5% by mass, 6% by mass, 7% by mass, 8% by mass, 9% by mass, or 10% by mass, and preferably about 1% by mass to about 5% by mass.

[0041] In the second monomer, the amount of hydroxy-containing monomer is not particularly limited and can be adjusted according to the actual application requirements. In some embodiments, the amount (percentage) of hydroxy-containing monomer relative to the total amount of monomers in the acrylic resin may be about 10% by mass to about 40% by mass, for example, about 10% by mass, 12% by mass, 14% by mass, 15% by mass, 16% by mass, 18% by mass, 20% by mass, 23% by mass, 24% by mass, 25% by mass, 26% by mass, 28% by mass, 30% by mass, 32% by mass, 34% by mass, 35% by mass, 36% by mass, 38% by mass, or 40% by mass, preferably about 20% by mass to about 30% by mass.

[0042] In the second monomer, the amount of isocyanate-containing monomer is not particularly limited and can be adjusted according to the actual application requirements. In some embodiments, the amount (percentage) of isocyanate-containing monomer relative to the total amount of monomers in the acrylic resin may be about 3% by mass to about 20% by mass, for example, about 3% by mass, 4% by mass, 5% by mass, 6% by mass, 8% by mass, 10% by mass, 12% by mass, 14% by mass, 15% by mass, 16% by mass, 18% by mass, or 20% by mass, and preferably about 7% by mass to about 15% by mass.

[0043] The acrylic resin content is not particularly limited and can be adjusted according to the actual application requirements. The acrylic resin content relative to the total mass (dry mass) of the adhesive composition can range from approximately 92% to approximately 99.9% by mass, for example, approximately 92%, 92.5%, 93%, 93.5%, 94%, 94.2%, 94.4%, 94.5%, 94.6%, 94.8%, 95%, 95.2%, 95.4%, 95.5%, 95.6%, 95.8%, 96%, 96.2%, 96.4%, 96.5%, 96.6%, 96.8%, 97%, 97.2%, and 97.4%. This includes, but is not limited to, mass, 97.5 mass, 97.6 mass, 97.8 mass%, 98 mass%, 98.5 mass%, 99 mass%, 99.2 mass%, 99.4 mass%, 99.5 mass%, 99.6 mass%, 99.8 mass%, or 99.9 mass%.

[0044] Crosslinking agent component of adhesive composition The crosslinking agents applicable to this disclosure are not particularly limited. In some embodiments, the crosslinking agent can thermally crosslink the acrylic resin at 80°C to 150°C, allowing the adhesive composition to form an adhesive layer after thermal crosslinking. In some embodiments, a suitable crosslinking agent may thermally crosslink with hydroxyl groups on the side chains of the acrylic resin described herein.

[0045] In some specific embodiments, the crosslinking agent includes isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, carbodiimide crosslinking agents, melamine resin crosslinking agents, urea resin crosslinking agents, anhydride crosslinking agents, polyamine crosslinking agents, carboxy-containing resin crosslinking agents, or metal crosslinking agents, preferably isocyanate crosslinking agents.

[0046] In this specification, "isocyanate crosslinking agent" refers to an isocyanate component that can undergo a thermal crosslinking reaction with the acrylic resin of this disclosure to form a crosslinked structure, and includes, but is not limited to, aliphatic cyclic isocyanate compounds or aliphatic acyclic isocyanate compounds.

[0047] Aliphatic cyclic isocyanate compounds include, but are not limited to, isocyanate compounds having ring structures other than aromatic rings, such as isophorone diisocyanate, methylenedicyclohexyl diisocyanate, cyclohexane diisocyanate, their derivatives, or reaction products thereof with polyols (e.g., trimethylolpropane).

[0048] Aliphatic acyclic isocyanate compounds include isocyanate compounds having aliphatic linear or branched chains, for example, C1 to C 20 This includes, but is not limited to, alkylene diisocyanate compounds, their derivatives, or reaction products thereof with polyols (e.g., trimethylolpropane). C1 to C 20 These alkylene diisocyanate compounds include, but are not limited to, hexamethylene diisocyanate (HDI), 1,2-ethylene diisocyanate, or 1,4-butylene diisocyanate.

[0049] The aforementioned crosslinking agents may be used alone or in combination.

[0050] The crosslinking agent content is not particularly limited and can be adjusted according to the actual application requirements. The crosslinking agent content relative to the total mass (dry mass) of the adhesive composition is, for example, about 0.01% to 10% by mass, such as about 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.5%, 2.6%, 2.8%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% by mass, but is not limited to these.

[0051] Photoinitiator component of adhesive composition The photoinitiator included in the adhesive composition can accelerate the photocuring of the acrylic resin. The photoinitiator used in this disclosure may include Norish type I photoinitiator and Norish type II photoinitiator.

[0052] The photoreaction of Norish type I photoinitiators is characterized by the generation of two radical fragments from the original photoinitiator after photodegradation. Upon light irradiation, the homogeneous bond is broken, generating two highly reactive radical substances, and at least one of these radicals reacts with the repeating units of the acrylic resin, initiating polymerization of the acrylic resin.

[0053] The photoreaction of Norrish type II photoinitiators is characterized by a major photochemical reaction: radical generation through the interaction of an excited aryl ketone compound with a hydrogen donor. The hydrogen donor molecule typically contains a heteroatom with an active hydrogen atom at the α-position. For example, tertiary amines, alcohols, ethers, esters, or thiols are commonly used donors. The molecular structure of Norrish type II photoinitiators does not decompose under ultraviolet irradiation; instead, electron transfer or hydrogen atom transfer occurs, thus preventing a decrease in molecular weight.

[0054] Compared to using adhesive compositions containing only Norish Type I photoinitiator or only Norish Type II photoinitiator, it was unexpectedly discovered that using an adhesive composition containing both Norish Type I and Norish Type II photoinitiators yields the following beneficial effects: Assuming the adhesive composition exhibits the desired adhesive strength (adhesion > 500 g / 25 mm) before photocuring and a good peel effect (adhesion < 10 g / 25 mm) after photocuring, the amount of Norish Type I photoinitiator fragments released is reduced under standard atmospheric conditions or in wafer cleaning solvents.

[0055] The ratio of Norish type II photoinitiator content to Norish type I photoinitiator content can be adjusted according to actual application requirements. In some embodiments, the mass ratio of the content of Norrish type II photoinitiator to Norrish type I photoinitiator may range from about 0.3 to about 8, for example, about 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2, 2.2, 2.4, 2.5, 2.6, 2.8, 3, 3.2, 3.4, 3.5, 3.6, 3.8, 4, 4.2, 4.4, 4.5, 4.6, 4.8, 5, 5.2, 5.4, 5.5, 5.6, 5.8, 6, 6.2, 6.4, 6.5, 6.6, 6.8, 7, 7.2, 7.4, 7.5, 7.6, 7.8, or 8. Generally, a smaller ratio yields a good peeling effect, but a less effective reduction in the amount of fragments released. When the ratio is large, the effect of reducing the amount of fragments released is good, but the peeling effect is poor. In some embodiments, in order to achieve a good balance of peelability of the composition, reduction of the amount of fragments released, and curing speed, the ratio of the content of Norish type II photoinitiator to the content of Norish type I photoinitiator is preferably 0.9 to 6.

[0056] Norish type I photoinitiators applicable to this disclosure are not particularly limited and include, but are selected from the group consisting of, for example, acetophenone, 4'-phenoxyacetophenone, 4'-ethoxyacetophenone, hydroxyacetophenone, α-aminoalkylphenone, α-dialkoxyacetophenone, benzyl ketals (also called azoacylketals), benzoin ethers and their derivatives, benzoyl esters, phosphine oxides, phenyl glyochlates, oximes and mixtures thereof.

[0057] Suitable hydroxyacetophenones include, but are not limited to, 3'-hydroxyacetophenone, 4'-hydroxyacetophenone, 1-hydroxycyclohexylphenyl ketone, or 2-hydroxy-2-methylpropiophenone.

[0058] Suitable α-aminoalkylphenones include, but are not limited to, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone (trademark: Irgacure 907) or 2-benzyl-2-(dimethylamino)-4'-morpholinobylophenone (trademark: Irgacure 369).

[0059] Suitable α-dialkoxyacetophenones include, but are not limited to, 2,2-diethoxyacetophenone.

[0060] Suitable benzyl ketals include, but are not limited to, 2,2-dimethoxy-2-phenylacetophenone or 2,2-diethoxy-2-phenylacetophenone.

[0061] Suitable benzoin ethers and their derivatives include, but are not limited to, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, anisoin, benzyl, or 4,4'-dimethylbenzyl.

[0062] Suitable phosphine oxides include, but are not limited to, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) or bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (trademark name: Irgacure 819).

[0063] Suitable oximes include, but are not limited to, 1-phenyl-1,2-propanedione-2-(O-ethoxycarboxy)oxime.

[0064] Other suitable Norish type I photoinitiators include, but are not limited to, (benzene)tricarbonylchromium, (cumene)cyclopentadienyl iron(II) hexafluorophosphate, ferrocene, methyl benzoylmate, triarylsulfonium hexafluoroantimonate, or triarylsulfonium hexafluorophosphate.

[0065] The aforementioned Norish Type I photoinitiators may be used alone or in combination.

[0066] Nourish type II photoinitiators applicable to this disclosure are not particularly limited and are selected from the group consisting of, for example, benzophenone (BP) and its derivatives, thioxanthene and its derivatives, and anthraquinone and its derivatives.

[0067] Suitable benzophenones and their derivatives include, but are not limited to, benzophenone (BP), 4-methylbenzophenone (4-MBP), 4,4'-bis(diethylamino)benzophenone, 2,5-dimethylbenzophenone, 3,4-dimethylbenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-dihydroxybenzophenone, 4-(dimethylamino)benzophenone, 3-hydroxybenzophenone, 4-hydroxybenzophenone, 2-methylbenzophenone, 3-methylbenzophenone, 3,3',4,4'-benzophenone tetracarboxylic acid dihydrate, 3,3'-dimethyl-4-methylbenzophenone, or 4-phenylbenzophenone (PBZ or 4-benzoylbiphenyl).

[0068] Suitable thioxanthenes and their derivatives include, but are not limited to, thioxanthenes, thioxanthenes-9-one, 2-isopropyl-9H-thioxanthenes-9-one (2-ITX), 4-isopropyl-9H-thioxanthenes-9-one (4-ITX), 2-chlorothioxanthenes-9-one, or 2,4-dimethyl-9H-thioxanthenes-9-one. It was unexpectedly found that when the Norish type II photoinitiator is a thioxanthene or its derivative, it is particularly advantageous that the ratio of the Norish type II photoinitiator content to the Norish type I photoinitiator content is greater than 1, preferably greater than 1.5.

[0069] Suitable anthraquinones and their derivatives include, but are not limited to, anthraquinone, anthraquinone-2-sulfonic acid, or 2-ethylanthraquinone.

[0070] Other suitable Norish type II photoinitiators include, but are not limited to, camphorquinone, dibenzosverenone, or phenanthrenequinone.

[0071] The aforementioned Norish II type photoinitiator may be used alone or in combination.

[0072] In some preferred embodiments, to achieve a good balance between delamination and reduction of fragment release, the combination of Norish type I and Norish type II photoinitiators may be configured such that the energy required to excite the Norish type II photoinitiator into a triplet state is greater than the energy required to excite the Norish type I photoinitiator into a triplet state. Some specific embodiments that satisfy the above conditions are shown in Table 1, for example, but are not limited to these.

[0073] [Table 1]

[0074] In this specification, the absorption wavelength peak of the photoinitiator is determined by measuring 0.1% by mass of the photoinitiator in an acetonitrile solution using a spectrophotometer.

[0075] Surprisingly, it was found that Norrish II photoinitiators have a long lifetime in the triplet excited state, making it possible to omit the quenching of the Norrish II photoinitiator to the triplet excited state with oxygen. This avoids radical generation failure in the presence of oxygen and makes it easier to remove wafer fragments from wafers diced in the presence of oxygen.

[0076] Surprisingly, it was found that the absorption spectrum of Norish type I photoinitiators can be shielded by pigments, but by adding Norish type II photoinitiators, it is possible to bypass the absorption wavelengths of the pigments, effectively transfer energy to excite the triplet state, and transition the Norish type I photoinitiator to the triplet state. This improves the curing rate of the adhesive composition.

[0077] The photoinitiator content is not particularly limited and can be adjusted according to the actual application requirements. The photoinitiator content relative to the total weight (dry weight) of the adhesive composition is, for example, about 0.1% to about 20% by mass, such as 0.1%, 0.2%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 2%, 4%, 5%, 6%, 8%, 10%, 12%, 14%, 15%, 16%, 18%, 20%, 22%, 24%, 25%, 26%, 28%, or 30%, preferably 0.5% to 10% by mass, but is not limited to these.

[0078] The adhesive composition may contain any of the conventional additives without impairing the objectives of the present invention, including, but is not limited to, crosslinking agents, tackifiers, fillers, flame retardants, anti-aging agents, antistatic agents, softeners, UV absorbers, antioxidants, plasticizers, surfactants, and colorants.

[0079] In some embodiments, the adhesive composition of the present disclosure may be prepared by the following method. All components of the adhesive composition including an acrylic resin, a crosslinking agent, a photoinitiator, and optionally additives are uniformly mixed with a stirrer to obtain a mixture. The obtained mixture is diluted with a suitable solvent as needed and adjusted to a desired concentration for subsequent steps. The solvent may be any inert solvent that can dissolve or disperse the components of the adhesive composition and does not react with those components. The amount of the solvent is not particularly limited as long as the components of the adhesive composition are uniformly dissolved or dispersed.

[0080] The type of radiation for curing the adhesive composition is appropriately set based on the formulation of the adhesive composition. Suitable radiations include, for example, but are not limited to, mercury lamps, deep ultraviolet rays, ultraviolet rays, or visible light. Ultraviolet rays with a wavelength of 250 nm to 400 nm are preferred for the adhesive tape used in the present disclosure. The radiation dose is not particularly limited, but an amount sufficient for the selected photoinitiator to cause a photochemical reaction is required. For example, from about 10 mJ / cm 2 to 3000 mJ / cm 2 , preferably from about 50 mJ / cm 2 to 2000 mJ / cm 2 , for example 350 mJ / cm 2 , but not limited thereto. If the radiation dose is insufficient, the adhesive composition will not be deformed and cured sufficiently to peel the tape, and mechanical damage will occur to the target product during peeling. If the radiation dose is excessively high, the adhesive composition will become brittle and remain on the target product during tape peeling. As used herein, the term "complete curing" means a sufficient radiation dose to minimize the adhesive strength of the cured adhesive composition.

[0081] The substrate may be used to support the adhesive composition. Suitable substrate forms include, but are not limited to, films, sheets, or plates. Suitable substrate materials include, but are not limited to, polyester, polycarbonate, polyethylene, polytetrafluoroethylene, polypropylene, polybutylene, polybutadiene, polyvinyl chloride, polyimide, polysulfone, polyurethane, poly(methyl methacrylate) (PMMA), polyolefin composite films, or cycloolefin polymers. Suitable polyesters include, but are not limited to, polyethylene terephthalate (PET) or polybutylene terephthalate (PBT). The thickness of the substrate is not particularly limited and may be selected according to the requirements of the actual application, for example, about 25 μm to 150 μm, but is not limited thereto.

[0082] The substrate surface may be surface-treated as needed before the adhesive composition is applied, and this may be a physical surface treatment such as plasma treatment or corona discharge treatment, or a chemical surface treatment such as primer application.

[0083] The method of placing the adhesive composition on the substrate is not particularly limited. For example, the adhesive composition may be coated onto the substrate, heated to thermally crosslink the adhesive composition, and form an adhesive layer. The suitable thickness of the adhesive layer is not particularly limited and may be adjusted according to the actual application requirements, for example, about 5 μm to 100 μm, but is not limited thereto. Suitable coating methods include, but are not limited to, gravure coating, roll coating, rod coating, blade coating, slit coating, spray coating, and die coating.

[0084] In some embodiments, the adhesive tape may further include a release film placed on the adhesive composition to protect the surface of the adhesive composition that does not come into contact with the substrate before use and to avoid external contamination. The material of the release film is not particularly limited and may be any film material that can be easily separated from the adhesive composition. The thickness of the release film is not particularly limited. Typically, considering cost and good protection, the thickness of the release film is about 10 μm to 100 μm. Furthermore, the surface of the release film may be pre-treated to facilitate the removal of the release film from the adhesive composition, for example, by treatment with silicone or fluorine.

[0085] After the adhesive tape hardens due to radiation, approximately 36mm 3 When an adhesive composition having a certain volume is measured by GC-MS in a 20 mL sealed space under standard conditions, the photoinitiator fragment content is approximately 1 ppm, 1.5 ppm, 2 ppm, 2.5 ppm, 3 ppm, 3.5 ppm, 4 ppm, 4.5 ppm, 5 ppm, 5.5 ppm, 6 ppm, 6.5 ppm, 7 ppm, 7.5 ppm, 8 ppm, 8.5 ppm, 9 ppm, 9.5 ppm, or 10 ppm. The maximum value in the range of photoinitiator fragment content may be any of the above values, and the minimum value may also be any of the above values. The range of photoinitiator fragment content may be any combination of the above values, for example, less than 10 ppm. The GC-MS measurement method for adhesive tapes and related radiation curing parameters are shown in the following examples.

[0086] Therefore, the adhesive tape of this disclosure offers the following excellent properties. The adhesive tape has good adhesion, can effectively secure the target product (e.g., wafer), and prevents the product from scattering during dicing; • The adhesive tape has high resistance to aqueous solutions or solvents, and therefore the amount of photoinitiator fragments leached out is low; • After light irradiation, the adhesive tape can be easily peeled off the target product, leaving almost no residue; and • When peeled off by light irradiation, the adhesive tape will contain small amounts of photoinitiator fragments. Embodiment

[0087] Next, the present disclosure will be described in more detail through embodiments. It should be noted herein that the following embodiments are for illustrative purposes only and should not be construed as limitations on the scope of the present disclosure. Non-essential improvements and adjustments to the present disclosure made by those skilled in the art based on the content of the present disclosure will still be within the scope of the present disclosure. Before discussing some non-limiting embodiments of the present disclosure, it should be understood that the present disclosure is not limited to the details of any specific non-limiting embodiments shown and described herein, and that the present disclosure may have other embodiments. Furthermore, the terms used herein to describe the present disclosure are for descriptive and non-limiting purposes only. Also, unless otherwise noted, the following descriptions by the same number refer to the same element.

[0088] Unless otherwise specified herein, the components contained in a solution, mixture, or composition are calculated based on their solid content (dry weight) (i.e., solvent weight is not included). Example 1: Preparation of adhesive composition

[0089] 65 parts by weight of 2-ethylhexyl acrylate, 2 parts by weight of acrylic acid, and 23 parts by weight of 2-hydroxyethyl acrylate were copolymerized using a conventional method to obtain an acrylic copolymer. 10 parts by weight of 2-methacryloyloxyethyl isocyanate (manufactured by Showa Denko Materials Co., Ltd., trademark name: Karenz MOI) could be reacted with the acrylic copolymer to obtain an acrylic resin with a weight-average molecular weight of approximately 600,000.

[0090] Sample 1 of adhesive composition was obtained by adding 0.6 parts by weight of the isocyanate crosslinking agent Desmodul L75 (manufactured by Polyurethane Industry Co., Ltd., Japan), 0.7 parts by weight of the Norish type I photoinitiator Diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide (TPO), and 1.4 parts by weight of the Norish type II photoinitiator 4-phenylbenzophenone (PBZ) to 100 parts by weight of acrylic resin, mixing and blending them.

[0091] The preparation methods for Samples 2 to 7 and Comparative Samples 1 to 3 are substantially the same as those for Sample 1, but the differences from Sample 1 are as follows: In Samples 2 to 7 and Comparative Samples 1 to 3, 0.7 parts by weight of TPO used in Sample 1 was replaced with the amount of Norish Type I photoinitiator listed in Table 2, and 1.4 parts by weight of PBZ used in Sample 1 was replaced with the amount of Norish Type II photoinitiator listed in Table 2.

[0092] [Table 2] Example 2: Preparation of adhesive tape

[0093] The adhesive compositions of Samples 1 to 7 and Comparative Samples 1 to 3 were each applied to a PET release film. The PET release film was a silicone-treated poly(ethylene terephthalate) film (50 μm thick) used as a release liner. The adhesive compositions of Samples 1 to 7 and Comparative Samples 1 to 3 were dried at 130°C for 2 minutes to form an adhesive layer approximately 60 μm thick. Next, the obtained adhesive layer was attached to a polyolefin composite film approximately 90 μm thick to obtain an adhesive tape. Example 3: Evaluation of outgassing amount of adhesive tape when peeled off by UV irradiation

[0094] Each adhesive tape from Sample 1 to Sample 7 and Comparative Sample 1 to Comparative Sample 3 was cut into 1.2 cm x 5 cm rectangles under yellow light (in this case, the volume of the adhesive layer / adhesive composition was approximately 36 mm³).3 This rectangular adhesive tape was flattened and fixed inside a 20 mL headspace bottle, then sealed with a cap. This created an airtight environment inside the headspace bottle under standard atmospheric conditions (1 atm, 25°C). The polyolefin composite film surface of the adhesive tape was irradiated with a wavelength of 365 nm and an irradiation energy of 350 mJ / cm². 2 The samples were exposed to ultraviolet light. After irradiation, the adhesive tape was left at room temperature (25°C) for 1 hour, and then heated at 60°C for 10 minutes. The concentration of volatile fragments of the photoinitiator generated from the adhesive composition and contained in the air inside the headspace bottle was analyzed by GC-MS. The results are shown in Table 3. The method for quantifying the concentration of volatile fragments of the photoinitiator is as follows: In the measured GC-MS spectrum, one or more mass spectral peaks corresponding to the photoinitiator used in the adhesive composition were separated, and the area between the mass spectral peak and the baseline was used for quantification based on an internal standard.

[0095] [Table 3]

[0096] Example 4: Evaluation of the adhesive strength of adhesive tape Each adhesive tape from Samples 1 to 7 and Comparative Samples 1 to 3 was cut into elongated strips 25 mm wide. These strips of adhesive tape were attached to polished glass under conditions of 1 atmosphere, 25°C, and 50% relative humidity. After leaving the samples in the same conditions for 20 minutes, the adhesive strength before UV irradiation was measured. The results are shown in Table 4. The polyolefin composite film surface of the adhesive tape was irradiated at a wavelength of 365 nm and an irradiation energy of 350 mJ / cm². 2 After exposure to ultraviolet light, the adhesive strength after UV irradiation was measured. The results are shown in Table 4. The method for measuring adhesive strength is as follows: A pressure-sensitive adhesive sheet for dicing is pulled in the peeling direction at a tensile speed of 300 mm / min, and the surface of the pressure-sensitive adhesive sheet and the glass surface are separated at a 180° angle. The force required for this separation is the adhesive strength.

[0097] [Table 4]

[0098] Those skilled in the art will understand that various modifications and variations of this disclosure are possible without departing from the scope or spirit of this disclosure. In view of the foregoing, this disclosure is intended to include modifications and variations of this disclosure, provided that they are included in the scope of the patent application and its equivalents.

Claims

1. The adhesive comprises a substrate and an adhesive composition disposed on the substrate, the adhesive composition comprising an acrylic resin, a crosslinking agent and a Norish type I photoinitiator, and after curing by ultraviolet irradiation at a wavelength of 365 nm, approximately 36 mm ３ An adhesive tape wherein the adhesive composition having a volume such that, when measured by gas chromatography-mass spectrometry in a 20 mL sealed space under standard conditions, yields a fragment content of less than 10 ppm of the Norish type I photoinitiator.

2. The adhesive tape according to claim 1, further comprising a Norish type II photoinitiator in the adhesive composition.

3. The adhesive tape according to claim 1, wherein the Norish type I photoinitiator comprises acetophenone, 4'-phenoxyacetophenone, 4'-ethoxyacetophenone, hydroxyacetophenone, α-aminoalkylphenone, α-dialkoxyacetophenone, benzyl ketals, benzoin ethers and their derivatives, benzoyl esters, phosphine oxides, phenylglyoxylates, oximes, or mixtures thereof.

4. The adhesive tape according to claim 2, wherein the Nolish type II photoinitiator comprises benzophenone and its derivatives, thioxanthene and its derivatives, anthraquinone and its derivatives, or a mixture thereof.

5. The adhesive tape according to claim 2, wherein the mass ratio of Norish type II photoinitiator to Norish type I photoinitiator is 0.3 to 8.

6. The adhesive tape according to claim 5, wherein the mass ratio of Norish type II photoinitiator to Norish type I photoinitiator is greater than 1 and 6 or less.

7. The Norish type I photoinitiator is acetophenone, 1-hydroxycyclohexylphenyl ketone, 4'-phenoxyacetophenone, 3'-hydroxyacetophenone, 4'-hydroxyacetophenone, anisoin, (benzene)tricarbonylchromium, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, 2-benzyl-2-(dimethylamino)-4'-morpholinobylophenone, (cumene)cyclopentadienyl iron(ii) hexafluorophosphate, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 4,4'-dimethylbenzyl, diphenyl The adhesive tape according to claim 3, wherein the adhesive tape is one or more selected from the group consisting of 2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methylpropiophenone, 4'-ethoxyacetophenone, ferrocene, methyl benzoylformate, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone, triarylsulfonium hexafluoroantimonate, triarylsulfonium hexafluorophosphate, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and 1-phenyl-1,2-propanedione-2-(O-ethoxycarboxy)oxime.

8. The aforementioned Norish type II photoinitiator is anthraquinone, anthraquinone-2-sulfonic acid, benzophenone, 3,3',4,4'-benzophenone tetracarboxylic acid dihydrate, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, camphorquinone, 2-chlorothioxanthene-9-one, dibenzosverenone, 4,4'-dihydroxybenzophenone, 4-(dimethylamino)benzophenone, 2,5-dimethylbenzophenone, 3,4-dimethylbenzophenone, 2-ethyl anth The adhesive tape according to claim 4, wherein the adhesive tape is one or more selected from the group consisting of raquinone, 3-hydroxybenzophenone, 4-hydroxybenzophenone, 2-methylbenzophenone, 3-methylbenzophenone, phenanthrenequinone, 2-isopropyl-9H-thioxanthene-9-one, 3,3'-dimethyl-4-methylbenzophenone, 4-phenylbenzophenone, 4-isopropyl-9h-thioxanthene-9-one, 2,4-dimethyl-9h-thioxanthene-9-one, thioxanthene, and thioxanthene-9-one.

9. The adhesive tape according to claim 1, wherein the monomers forming the acrylic resin comprises one or more first monomers and one or more second monomers different from the first monomers, and one or more of the first monomers are selected from the group consisting of alkyl esters of (meth)acrylic acid, cycloalkyl esters of (meth)acrylic acid, and aryl esters of (meth)acrylic acid.

10. The adhesive tape according to claim 9, wherein one or more of the second monomers include a carboxyl-containing monomer, a hydroxyl-containing monomer, and an isocyanate-containing monomer.

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