Adhesive tape for electronic component processing and method for manufacturing electronic component

Abstract

The present disclosure provides an adhesive tape for electronic component processing, the adhesive tape having: a mesh sheet; and a photocurable adhesive layer disposed on a first surface of the mesh sheet so as to be in contact with the mesh sheet. When the tape is irradiated with light in atmospheric air using an electrodeless lamp, the adhesive strength of the tape with respect to a glass plate before light irradiation is 5 N / 25 mm or more, and the adhesive strength with respect to a glass plate after light irradiation is less than 0.7 N / 25 mm, where the adhesive strength decrease ratio represented by formula (1) is 92% or more. Formula (1): Adhesive strength reduction ratio (%) = [1-(adhesive strength with respect to glass plate after light irradiation / adhesive strength with respect to glass plate before light irradiation) ] × 100

Description

Adhesive tape for processing electronic components and method for manufacturing electronic components

[0001] The present disclosure relates to an adhesive tape for processing electronic components and a method for manufacturing electronic components.

[0002] In a so-called dicing process in which a substrate to be processed is divided into chips, an adhesive tape called a dicing tape is used to protect and fix the substrate to be processed and the chips.

[0003] As such adhesive tapes, for example, photo-curing adhesive tapes have been actively developed.

[0004] Recently, a dicing method using a laser guided by a water jet has been proposed, which will be referred to as water jet laser processing hereinafter.

[0005] An adhesive tape usually has a substrate and an adhesive layer. For example, as described in Patent Documents 1 to 4, in the case of water jet laser processing, a mesh sheet or the like that is permeable to water flow is used as the substrate constituting the adhesive tape in order to suppress chipping due to splashing of water.

[0006] Japanese Patent No. 3824874 Japanese Patent No. 4087144 Japanese Patent No. 5000370 Japanese Patent Laid-Open No. 2005-167042

[0007] In photocurable adhesive tapes, the adhesive layer is cured by exposure to light, reducing the adhesive strength. When a mesh sheet is used, oxygen in the air comes into contact with the adhesive layer through the openings in the mesh sheet, which can inhibit curing of the adhesive layer. If the adhesive layer does not cure sufficiently, the adhesive strength of the adhesive layer will not decrease sufficiently, resulting in cracks or chips in the chip when the adhesive tape is peeled off.

[0008] One known method for preventing curing inhibition due to atmospheric oxygen is to purge with nitrogen, but this requires additional equipment and is costly.

[0009] Furthermore, Patent Document 2 proposes a technology for an adhesive tape used in water jet laser processing, in which a non-curable adhesive layer is disposed between a substrate and a curable adhesive layer, thereby blocking contact between the curable adhesive layer and oxygen and suppressing curing inhibition due to oxygen in the atmosphere. However, when the adhesive tape further includes a non-curable adhesive layer, the number of manufacturing steps increases, resulting in higher costs.

[0010] The present disclosure has been made in consideration of the above-mentioned circumstances, and has as its main object to provide an adhesive tape for processing electronic components, which has a photocurable adhesive layer disposed in contact with a mesh sheet, and which is capable of suppressing curing inhibition by oxygen.

[0011] One embodiment of the present disclosure provides an adhesive tape for processing electronic components, the adhesive tape having a mesh sheet and a photocurable adhesive layer disposed on a first surface of the mesh sheet in contact with the mesh sheet, wherein, when irradiated with light from an electrodeless lamp under atmospheric pressure, the adhesive tape has an adhesive strength to a glass plate of 5 N / 25 mm or more before light irradiation and an adhesive strength to a glass plate of less than 0.7 N / 25 mm after light irradiation, and an adhesive strength reduction rate represented by the following formula (1) of 92% or more: Adhesive strength reduction rate (%) = [1 - (adhesive strength to glass plate after light irradiation / adhesive strength to glass plate before light irradiation)] x 100 (1)

[0012] Another embodiment of the present disclosure provides an adhesive tape for processing electronic components, the adhesive tape having a mesh sheet and a photocurable adhesive layer disposed on a first surface of the mesh sheet in contact with the mesh sheet, wherein, when irradiated with light using a black light under atmospheric pressure, the adhesive tape has an adhesive strength to a glass plate before light irradiation of 5 N / 25 mm or more and an adhesive strength to a glass plate after light irradiation of less than 0.7 N / 25 mm, and an adhesive strength reduction rate represented by the following formula (1) of 92% or more: Adhesive strength reduction rate (%) = [1 - (adhesive strength to glass plate after light irradiation / adhesive strength to glass plate before light irradiation)] x 100 (2)

[0013] Another embodiment of the present disclosure provides a method for manufacturing electronic components, including an attachment step of attaching the above-mentioned adhesive tape for electronic component processing to a first surface of a workpiece substrate, a dicing step of dividing the workpiece substrate into a plurality of chips, an irradiation step of irradiating the adhesive layer of the adhesive tape for electronic component processing with light to harden it, and a peeling step of peeling the adhesive tape for electronic component processing from the chip.

[0014] The present disclosure can provide an adhesive tape for processing electronic components that can suppress curing inhibition due to oxygen.

[0015] Fig. 1 is a schematic cross-sectional view illustrating an example of an adhesive tape for electronic component processing according to the present disclosure; Fig. 2 is a schematic cross-sectional view illustrating an example of an adhesive tape for electronic component processing according to the present disclosure; Fig. 3 is a schematic plan view and a cross-sectional view illustrating an example of a mesh sheet constituting the adhesive tape for electronic component processing according to the present disclosure; Fig. 4 is a process diagram illustrating an example of a method for manufacturing an electronic component according to the present disclosure; Fig. 5 is a process diagram illustrating an example of a method for manufacturing an electronic component according to the present disclosure.

[0016] Embodiments of the present disclosure will be described below with reference to the drawings and the like. However, the present disclosure can be implemented in many different forms and should not be limited to the description of the embodiments exemplified below. Furthermore, in order to clarify the description, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the actual form, but these are merely examples and should not be interpreted as being limiting. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings will be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0017] In this specification, when describing a mode in which another component is placed on a certain component, the term "above" or "below" includes, unless otherwise specified, both a case in which another component is placed directly above or below a certain component so as to be in contact with the component, and a case in which another component is placed above or below a certain component with another component interposed therebetween. Also, in this specification, when describing a mode in which another component is placed on the surface of a certain component, the term "on the surface" includes, unless otherwise specified, both a case in which another component is placed directly above or below a certain component so as to be in contact with the component, and a case in which another component is placed above or below a certain component with another component interposed therebetween.

[0018] In this specification, the term "sheet" also includes a member called a "film."

[0019] The adhesive tape for processing electronic components and the method for manufacturing electronic components according to the present disclosure will be described below.

[0020] A. Adhesive Tape for Processing Electronic Components The adhesive tape for processing electronic components according to the present disclosure has two embodiments. Each embodiment will be described below.

[0021] I. First Embodiment A first embodiment of the adhesive tape for electronic component processing according to the present disclosure is an adhesive tape for electronic component processing having a mesh sheet and a photocurable adhesive layer disposed on a first surface of the mesh sheet in contact with the mesh sheet, wherein when irradiated with light using an electrodeless lamp under atmospheric pressure, the adhesive strength to a glass plate before light irradiation is 5 N / 25 mm or more, and the adhesive strength to a glass plate after light irradiation is less than 0.7 N / 25 mm, and the adhesive strength reduction rate represented by the following formula (1) is 92% or more: Adhesive strength reduction rate (%) = [1 - (adhesive strength to glass plate after light irradiation / adhesive strength to glass plate before light irradiation)] × 100 (1)

[0022] Fig. 1 is a schematic cross-sectional view illustrating an example of an adhesive tape for electronic component processing according to this embodiment. As illustrated in Fig. 1, the adhesive tape for electronic component processing 10 includes a mesh sheet 1 and a photocurable adhesive layer 2 disposed on a first surface of the mesh sheet 1 in contact with the mesh sheet 1.

[0023] In this embodiment, the photocurable adhesive layer is cured by light irradiation, and its adhesive strength is reduced. If the adhesive layer is sufficiently cured even in the atmosphere and its adhesive strength is reduced, the adhesive strength reduction rate will be large. On the other hand, if the adhesive layer is not sufficiently cured in the atmosphere, the adhesive strength reduction rate will be small. Therefore, the larger the adhesive strength reduction rate, the more effective it is in suppressing curing inhibition by oxygen.

[0024] Therefore, in this embodiment, by ensuring that the adhesive strength reduction rate is equal to or greater than a predetermined value, it is possible to suppress curing inhibition due to oxygen. As a result, the adhesive layer can be easily peeled off after light irradiation, which prevents chip cracking or chipping when the adhesive tape for processing electronic components is peeled off. Furthermore, since there is no need for nitrogen purging during light irradiation and light irradiation can be performed in the atmosphere, it is possible to reduce costs and improve workability.

[0025] Hereinafter, each component of the adhesive tape for processing electronic parts according to this embodiment will be described.

[0026] 1. Properties of the adhesive tape for electronic component processing (1) Adhesion to glass plate In the adhesive tape for electronic component processing of this embodiment, the adhesive strength to a glass plate before light irradiation is 5 N / 25 mm or more, or may be 10 N / 25 mm or more, or may be 20 N / 25 mm or more. When the adhesive strength is within the above range, the adhesion between the adhesive sheet for electronic components and the substrate or chip to be processed is improved, and the occurrence of chip flying during water jet laser processing can be suppressed. On the other hand, the adhesive strength to a glass plate before light irradiation is, for example, 40 N / 25 mm or less.

[0027] The adhesive strength to the glass plate before light irradiation is measured in accordance with Method 1 of the test method of JIS Z0237:2022 (Test method for adhesive tapes and adhesive sheets) (a test method in which the tape and sheet are peeled off at 180° from a stainless steel test plate at a temperature of 23°C and a humidity of 50%) by peeling the test piece in the length direction under the conditions of a width of 25 mm, a peel angle of 180°, and a peel speed of 300 mm / min. The glass plate used is a float glass plate (size 150 mm x 70 mm, thickness 2 mm) manufactured by Osaka Glass Industry Co., Ltd.

[0028] Furthermore, when the adhesive tape for electronic component processing of this embodiment is irradiated with light in the atmosphere using an electrodeless lamp, the adhesive strength to a glass plate after light irradiation is less than 0.7 N / 25 mm, and may be 0.3 N / 25 mm or less, or may be 0.1 N / 25 mm or less. When the adhesive strength is within the above range, the adhesive tape for electronic component processing can be easily peeled off after light irradiation. Meanwhile, the lower limit of the adhesive strength to a glass plate after light irradiation is, for example, 0.01 N / 25 mm or more, because it is necessary to hold the chip during transportation.

[0029] The adhesive strength to a glass plate after light irradiation is measured by the following method. First, in accordance with Method 1 of the test method of JIS Z0237:2022 (Test method for adhesive tapes and adhesive sheets) (a test method in which the tape and sheet are peeled at 180° from a stainless steel test plate at a temperature of 23°C and a humidity of 50%), a 25 mm wide test piece is taken from the adhesive tape for electronic component processing and the test piece is attached to a glass plate. The glass plate is a float glass plate (size 150 mm x 70 mm, thickness 2 mm) manufactured by Osaka Glass Industry Co., Ltd. Next, using an electrodeless UV lamp system manufactured by Heraeus, an integrated light intensity of 500 mJ / cm at a wavelength of 365 nm is measured. ２ The electrodeless lamp bulb of the electrodeless UV lamp system is an H bulb manufactured by Heraeus. Next, in accordance with JIS Z0237:2022 (Test method for adhesive tapes and adhesive sheets), Method 1 (temperature 23 ° C., humidity 50%, test method in which the tape and sheet are peeled at 180 ° from the stainless steel test plate), the adhesive strength to the glass plate is measured by peeling the test piece in the length direction under conditions of a peel angle of 180 ° and a peel speed of 300 mm / min.

[0030] The Heraeus H-Bulb electrodeless lamp reproduces the spectrum of a high-pressure mercury lamp and efficiently emits wavelengths of 254 nm, 313 nm, and 365 nm. High-pressure mercury lamps or electrodeless lamps that reproduce the spectrum of a high-pressure mercury lamp are often used as light irradiation devices. Therefore, in this embodiment, the Heraeus H-Bulb electrodeless lamp was used to measure the adhesive strength to the glass plate after light irradiation.

[0031] (2) Adhesive Strength Reduction Rate In the adhesive tape for electronic component processing of this embodiment, when irradiated with light in the atmosphere using an electrodeless lamp, the adhesive strength reduction rate represented by the following formula (1) is 92% or more, or may be 95% or more, or may be 99% or more. When the adhesive strength reduction rate is equal to or greater than a predetermined value, curing inhibition due to oxygen can be suppressed. On the other hand, as described above, the larger the adhesive strength reduction rate, the more effective it is in suppressing curing inhibition due to oxygen, so the upper limit of the adhesive strength reduction rate is not particularly limited.

[0032] Adhesive strength reduction rate (%) = [1 - (adhesive strength to glass plate after light irradiation / adhesive strength to glass plate before light irradiation)] × 100 (1)

[0033] The method for measuring the adhesive strength to the glass plate before light irradiation and the method for measuring the adhesive strength to the glass plate after light irradiation are as described above.

[0034] Methods for controlling the rate of decrease in adhesive strength include, for example, adjusting the light transmittance of the mesh sheet, adjusting the light transmittance of the adhesive layer, adjusting the content of the polymerization initiator in the adhesive layer, adjusting the type of polymerization initiator, adjusting the number of functional groups in the photocurable compound, adjusting the content of the photocurable compound in the adhesive layer, and adjusting the type of photocurable compound.

[0035] The high light transmittance of the mesh sheet and the adhesive layer allows the light to penetrate deep into the adhesive layer when the adhesive tape for electronic component processing is irradiated with light from the mesh sheet side, enhancing internal curing properties, thereby reducing the adhesive strength to a glass plate after light irradiation in the atmosphere and increasing the rate of adhesive strength reduction.

[0036] By increasing the content of the polymerization initiator in the adhesive layer, the amount of active species generated from the polymerization initiator increases, thereby improving the curability, and therefore reducing the adhesive strength to the glass plate after light irradiation in the atmosphere, thereby increasing the rate of reduction in adhesive strength.

[0037] By using a polymerization initiator that generates active species with high reactivity, it is possible to enhance curing properties. Therefore, it is possible to reduce adhesive strength to a glass plate after light irradiation in the atmosphere, and to increase the rate of adhesive strength reduction. Specifically, examples of polymerization initiators that generate active species with high reactivity include oxime esters.

[0038] 2. Adhesive Layer The adhesive layer in this embodiment is a photocurable member disposed on the first surface of the mesh sheet. The photocurable adhesive layer reduces its adhesive strength by being cured by light irradiation. In the dicing process, the photocurable adhesive layer can fix the substrate to be processed and the divided chips due to its initial adhesive strength. Furthermore, in the peeling process, the photocurable adhesive layer is cured by being irradiated with light, reducing its adhesive strength and improving peelability, allowing it to be peeled from the chips.

[0039] Examples of light include ultraviolet light and visible light, with ultraviolet light being preferred.

[0040] (1) Material of the Adhesive Layer The adhesive layer is not particularly limited as long as it satisfies the above-mentioned characteristics, and may contain, for example, a resin (main adhesive agent), a photocurable compound, and a polymerization initiator. When the adhesive layer contains a photocurable compound, the photocurable compound can be cured by light irradiation, thereby reducing the adhesive strength. In addition, the cohesive force increases at this time, making it easier to peel.

[0041] (a) Resin (adhesive base) Examples of the resin (adhesive base) include resins generally used as the base of adhesives, such as acrylic resins, polyester resins, polyimide resins, and silicone resins. Among these, acrylic resins are preferred. By using acrylic resins, adhesive residue on the adherend can be reduced.

[0042] Therefore, the adhesive layer preferably contains an acrylic resin, a photocurable compound, a polymerization initiator, and a crosslinking agent. In the adhesive layer, the acrylic resin is usually present as a crosslinked body formed by crosslinking between acrylic resin molecules with the crosslinking agent, but the acrylic resin may also be present as a simple substance together with the crosslinked body.

[0043] (Acrylic Resin) The acrylic resin is not particularly limited, and examples thereof include (meth)acrylic acid ester polymers obtained by homopolymerizing (meth)acrylic acid esters, and (meth)acrylic acid ester copolymers obtained by copolymerizing (meth)acrylic acid esters with other monomers and (meth)acrylic acid esters as the main component. Among these, (meth)acrylic acid ester copolymers are preferred. Specific examples of (meth)acrylic acid esters and other monomers include those disclosed in JP 2012-31316 A. The other monomers can be used alone or in combination of two or more. Note that the term "main component" here means that the copolymerization ratio is 51% by mass or more, preferably 65% ​​by mass or more.

[0044] Among these, as the acrylic resin, a (meth)acrylic acid ester copolymer obtained by copolymerizing a (meth)acrylic acid ester as the main component with a hydroxyl group-containing monomer copolymerizable with the (meth)acrylic acid ester, or a (meth)acrylic acid ester copolymer obtained by copolymerizing a (meth)acrylic acid ester as the main component with a hydroxyl group-containing monomer and a carboxyl group-containing monomer copolymerizable with the (meth)acrylic acid ester can be preferably used.

[0045] In this specification, (meth)acrylic acid refers to at least one of acrylic acid and methacrylic acid.

[0046] The copolymerizable hydroxyl group-containing monomer and carboxyl group-containing monomer are not particularly limited, and for example, the hydroxyl group-containing monomer and carboxyl group-containing monomer disclosed in JP-A-2012-31316 can be used.

[0047] The weight-average molecular weight of the acrylic resin is, for example, preferably from 10,000 to 1,000,000, and more preferably from 200,000 to 800,000. By setting the weight-average molecular weight of the acrylic resin within the above range, sufficient initial adhesive strength can be exhibited.

[0048] In this specification, the weight-average molecular weight is a polystyrene-equivalent value measured by gel permeation chromatography (GPC). The weight-average molecular weight is measured, for example, using a measuring device HLC-8220GPC manufactured by Tosoh Corporation, a column TSKGEL-SUPERMULTIPORE-HZ-M manufactured by Tosoh Corporation, THF as a solvent, and standard polystyrenes with molecular weights of 1050, 5970, 18100, 37900, 96400, and 706000 as standards.

[0049] Furthermore, when the acrylic resin is a (meth)acrylic acid ester copolymer of a hydroxyl group-containing monomer and a carboxyl group-containing monomer copolymerizable with a (meth)acrylic acid ester, the mass ratio of the hydroxyl group-containing monomer to the carboxyl group-containing monomer is, for example, preferably 51:49 to 100:0, and more preferably 75:25 to 100:0. If the mass ratio of the monomers is within the above range, effective reduction in adhesive strength due to light irradiation can be expected, and the occurrence of adhesive residue can be suppressed.

[0050] The acrylic resin may be photocurable, for example, may have a photocurable functional group in a side chain. The photocurable functional group preferably has an ethylenically unsaturated bond, and specific examples thereof include a (meth)acryloyl group, a vinyl group, and an allyl group.

[0051] (b) Photocurable Compound The photocurable compound is not particularly limited as long as it is polymerizable by irradiation with light, and examples thereof include compounds having a photocurable functional group.

[0052] Examples of photocurable compounds include photocurable monomers, photocurable oligomers, and photocurable polymers. The photocurable polymer is a polymer different from the resin (main adhesive agent) described above. Among these, photocurable oligomers are preferred from the viewpoint of the balance of adhesive strength before and after light irradiation. Furthermore, photocurable monomers, photocurable oligomers, and photocurable polymers may be used in combination. For example, when a photocurable monomer is used in addition to a photocurable oligomer, the adhesive layer is cured by three-dimensional crosslinking upon light irradiation, thereby reducing adhesive strength and increasing cohesive strength to prevent transfer to the chip side.

[0053] Examples of photocurable compounds include radically polymerizable compounds, cationic polymerizable compounds, and anionic polymerizable compounds. Among these, radically polymerizable compounds are preferred. They have a fast curing rate, can be selected from a wide variety of compounds, and can easily control physical properties such as adhesive strength before and after light irradiation.

[0054] In addition, the adhesive strength after the light irradiation can be controlled by adjusting the number of photocurable functional groups in the photocurable compound. As described above, for example, as the number of photocurable functional groups increases, the crosslink density of the adhesive layer after the light irradiation increases, and the adhesive strength after the light irradiation tends to decrease.

[0055] In the photocurable compound, the number of photocurable functional groups per molecule is preferably 2 or more, more preferably 3 or more, and even more preferably 4 or more. If the number of photocurable functional groups is within the above range, the crosslinking density of the adhesive layer after light irradiation is sufficient, thereby achieving the desired peelability. In addition, the occurrence of adhesive residue due to a decrease in cohesive force can be suppressed. In addition, the upper limit of the number of photocurable functional groups is not particularly limited.

[0056] The photocurable compound is preferably a radical polymerizable oligomer, more preferably a radical polymerizable polyfunctional oligomer, such as those disclosed in JP 2012-31316 A.

[0057] Furthermore, as the photocurable compound, a radical polymerizable oligomer or a radical polymerizable monomer may be used, and in particular, a radical polymerizable polyfunctional oligomer or a radical polymerizable polyfunctional monomer may be used. Examples of the radical polymerizable monomer include those disclosed in JP 2010-173091 A.

[0058] Examples of the photocurable compound include (meth)acrylate monomers, (meth)acrylate oligomers, and (meth)acrylate polymers. Examples of the photocurable compound that can be used include urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate.

[0059] Alternatively, commercially available photocurable compounds may be used. For example, urethane acrylate "Shiko UV7620EA (molecular weight: 4100)" manufactured by Mitsubishi Chemical Corporation, and urethane acrylates "Art Resin UN-905 (molecular weight: 50,000 to 210,000)," "Art Resin UN-905DU1 (molecular weight: 26,000)," "Art Resin UN-951SC (molecular weight: 12,500)," "Art Resin UN-952 (molecular weight: 6,500 to 9,500)," "Art Resin UN-953 (molecular weight: 14,000 to 40,000)," "Art Resin UN-954 (molecular weight: 4,200)," and "Art Resin H-219 (molecular weight: 14,000 to 40,000)" manufactured by Negami Chemical Industrial Co., Ltd. Examples of such polymers include "Art Resin H-315M (molecular weight: 6600)" and "Art Resin H-417M (molecular weight: 4000)" manufactured by Taisei Fine Chemical Co., Ltd., an acrylic urethane polymer "8BR-600 (molecular weight: 100000)" manufactured by Taisei Fine Chemical Co., Ltd., a polymer acrylate "Unidic V-6850" manufactured by DIC Corporation, an acrylic polymer "SMP-250AP (molecular weight: 20000-30000)" and "SMP-360A (molecular weight: 20000-30000)" manufactured by Kyoeisha Chemical Co., Ltd., and an acrylic resin acrylate "HA7975" manufactured by Showa Denko Materials Inc.

[0060] The photocurable compounds may be used alone or in combination of two or more.

[0061] The weight-average molecular weight of the photocurable compound is not particularly limited, but is preferably 30,000 or less, more preferably 10,000 or less, and even more preferably 8,000 or less. If the weight-average molecular weight of the photocurable compound is within the above range, it will exhibit sufficient compatibility with the acrylic resin (main adhesive agent), and the adhesive layer will exhibit the desired adhesive strength before light irradiation, and after light irradiation, the occurrence of adhesive residue will be suppressed and it will be easily peelable. On the other hand, the weight-average molecular weight of the photocurable resin composition will be, for example, 500 or more.

[0062] Furthermore, the adhesive strength after light irradiation can be controlled by adjusting the content of the photocurable compound. If the content of the photocurable compound is high, the adhesive strength after light irradiation tends to be low.

[0063] The content of the photocurable compound is, for example, preferably 5 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 50 parts by mass or more, per 100 parts by mass of the resin (main adhesive). The content of the photocurable compound is, for example, preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 80 parts by mass or less, per 100 parts by mass of the resin (main adhesive). That is, the content of the photocurable compound is, for example, preferably 5 parts by mass or more and 150 parts by mass or less, more preferably 20 parts by mass or more and 100 parts by mass or less, and even more preferably 50 parts by mass or more and 80 parts by mass or less, per 100 parts by mass of the resin (main adhesive). If the content of the photocurable compound is within the above range, the crosslink density of the adhesive layer after light irradiation is sufficient, thereby achieving the desired peelability. Furthermore, the occurrence of adhesive residue due to a decrease in cohesive force can be suppressed.

[0064] (c) Polymerization Initiator As the polymerization initiator, a general photopolymerization initiator can be used, among which acylphosphine oxide-based, α-hydroxyalkylphenone-based, and oxime ester-based initiators are preferred.

[0065] Examples of the acylphosphine oxide polymerization initiator include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and ethyl(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0066] An example of the α-hydroxyalkylphenone polymerization initiator is 1-hydroxycyclohexyl-phenyl ketone.

[0067] Examples of the oxime ester polymerization initiator include 1,2-octanedione-1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime) and ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime).

[0068] As described below, resins or the like can be used for the mesh sheet, and many resins absorb light with wavelengths up to about 300 nm but transmit light with wavelengths of 300 nm or more. Acylphosphine oxide-based polymerization initiators tend to have relatively high absorption in the wavelength range of 350 nm or more. Therefore, acylphosphine oxide-based polymerization initiators can absorb a wide range of light with wavelengths of 300 nm or more and efficiently generate active species. Furthermore, acylphosphine oxide-based polymerization initiators have a photobleaching effect and are excellent in internal curing properties. Therefore, by increasing the content of acylphosphine oxide-based polymerization initiator in the adhesive layer, the amount of active species generated can be increased, thereby improving curing properties. Therefore, the adhesive strength to a glass plate after light irradiation in the atmosphere can be reduced, and the adhesive strength reduction rate can be increased.

[0069] Specifically, the content of the acylphosphine oxide polymerization initiator in the adhesive layer is preferably 7.5 parts by mass or more per 100 parts by mass of the resin (main adhesive). A high content of the acylphosphine oxide polymerization initiator within the above range can increase the adhesive strength reduction rate, as described above. On the other hand, the content of the acylphosphine oxide polymerization initiator in the adhesive layer is, for example, 20 parts by mass or less per 100 parts by mass of the resin (main adhesive). If the content of the acylphosphine oxide polymerization initiator is too high, the cohesive strength will decrease, which may cause adhesive residue.

[0070] Note that because polymerization initiators are expensive, it is not common to increase the content of polymerization initiator to the above range. Furthermore, if the content of polymerization initiator is high, when the adhesive layer is irradiated with light to cure, the transmittance of the dominant wavelength decreases, making it difficult for light to reach the depths (surface layer) of the adhesive layer, which may result in a decrease in adhesive strength. Specifically, when the content of polymerization initiator is 7.5 parts by mass per 100 parts by mass of resin (main adhesive), approximately 63% of the dominant wavelength is absorbed. Furthermore, when the content of polymerization initiator is 20 parts by mass per 100 parts by mass of resin (main adhesive), approximately 97% of the dominant wavelength is absorbed. This has a significant effect when using a single-wavelength light source such as an LED or black light.

[0071] Furthermore, the absorption wavelength peaks of the acylphosphine oxide polymerization initiator and the α-hydroxyalkylphenone polymerization initiator are different. Therefore, by using a combination of the acylphosphine oxide polymerization initiator and the α-hydroxyalkylphenone polymerization initiator, light can be absorbed over a wide range and active species can be efficiently generated. Furthermore, as described above, the acylphosphine oxide polymerization initiator has a photobleaching effect and is excellent in internal curing properties. Therefore, by using a combination of the acylphosphine oxide polymerization initiator and the α-hydroxyalkylphenone polymerization initiator, the amount of active species generated can be increased, thereby improving curing properties. Therefore, the adhesive strength to a glass plate after light irradiation in the atmosphere can be reduced, and the adhesive strength reduction rate can be increased.

[0072] When an acylphosphine oxide polymerization initiator and an α-hydroxyalkylphenone polymerization initiator are used in combination, the total content of the acylphosphine oxide polymerization initiator and the α-hydroxyalkylphenone polymerization initiator in the adhesive layer is, for example, 0.5 parts by mass or more, and may be 5 parts by mass or more, per 100 parts by mass of the resin (main adhesive). On the other hand, the total content may be, for example, 20 parts by mass or less, and may be 10 parts by mass or less, per 100 parts by mass of the resin (main adhesive). If the total content is too low, the polymerization reaction of the photocurable compound may not occur sufficiently, resulting in excessively high adhesive strength of the adhesive layer after light irradiation, making it difficult to achieve peelability. On the other hand, if the total content is too high, the cohesive strength may decrease, potentially causing adhesive residue. Specifically, the total content may be 0.5 parts by mass or more and 20 parts by mass or less, and may be 5 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of the resin (main adhesive).

[0073] In addition, the oxime ester polymerization initiator generates active species with high reactivity, which can enhance curing properties. Furthermore, the oxime ester polymerization initiator easily breaks bonds upon light irradiation to generate radicals, resulting in high reactivity. Therefore, the adhesive strength to a glass plate after light irradiation in the atmosphere can be reduced, and the adhesive strength reduction rate can be increased.

[0074] The content of the oxime ester polymerization initiator in the adhesive layer may be, for example, 0.5 parts by mass or more, or may be 5 parts by mass or more, per 100 parts by mass of the resin (main adhesive). On the other hand, the content may be, for example, 20 parts by mass or less, or may be 10 parts by mass or less, per 100 parts by mass of the resin (main adhesive). If the content is too low, the polymerization reaction of the photocurable compound may not occur sufficiently, resulting in excessively high adhesive strength of the adhesive layer after light irradiation, making it difficult to achieve peelability. On the other hand, if the content is too high, the cohesive strength may decrease, potentially causing adhesive residue. Specifically, the content may be 0.5 parts by mass or more and 20 parts by mass or less, or may be 5 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of the resin (main adhesive).

[0075] The oxime ester polymerization initiator may also be combined with another polymerization initiator. In this case, the same effect as described above is achieved. The other polymerization initiator is not particularly limited as long as it does not have absorption that inhibits polymerization by the oxime ester polymerization initiator. However, an acylphosphine oxide polymerization initiator is preferred. As described above, the acylphosphine oxide polymerization initiator has a photobleaching effect, and therefore is thought to be less likely to inhibit polymerization by the oxime ester polymerization initiator. In this case, the total content of the oxime ester polymerization initiator and the other polymerization initiator in the adhesive layer may be, for example, 0.5 parts by mass or more and may be 5 parts by mass or more per 100 parts by mass of the resin (main adhesive). Meanwhile, the total content may be, for example, 20 parts by mass or less and may be 10 parts by mass or less per 100 parts by mass of the resin (main adhesive). That is, the total content may be, for example, 0.5 parts by mass or more and 20 parts by mass or less and 5 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the resin (main adhesive). If the total content is too low, the polymerization reaction of the photocurable compound does not occur sufficiently, and the adhesive strength of the adhesive layer after light irradiation becomes excessively high, which may result in failure to achieve peelability.On the other hand, if the total content is too high, the cohesive strength decreases, which may cause adhesive residue.

[0076] (d) Crosslinking Agent The adhesive layer may contain a crosslinking agent in addition to the resin (main adhesive agent) and the photocurable compound.

[0077] The crosslinking agent is not particularly limited as long as it crosslinks at least between resins (main adhesive agents), and is appropriately selected depending on the type of resin (main adhesive agent), etc. Examples include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and metal chelate-based crosslinking agents. Specific examples of isocyanate-based crosslinking agents and epoxy-based crosslinking agents include those disclosed in JP 2012-31316 A. The crosslinking agents can be used alone or in combination of two or more.

[0078] The content of the crosslinking agent is appropriately set depending on the type of crosslinking agent. For example, it is preferably 0.01 to 15 parts by mass, more preferably 0.01 to 10 parts by mass, per 100 parts by mass of resin (main adhesive). If the content of the crosslinking agent is less than the above range, the adhesion may be poor, or the adhesive layer may undergo cohesive failure when peeling off the chip, resulting in adhesive residue. On the other hand, if the content of the crosslinking agent exceeds the above range, the crosslinking agent may remain in the adhesive layer as an unreacted monomer after light irradiation, which may cause adhesive residue due to a decrease in cohesive force.

[0079] (e) Additives The adhesive layer may contain various additives as needed, such as a tackifier, an antistatic agent, a plasticizer, a silane coupling agent, a metal chelating agent, a surfactant, an antioxidant, an ultraviolet absorber, a colorant, a preservative, an antifoaming agent, and a wettability adjuster.

[0080] (2) Thickness of the Adhesive Layer The thickness of the adhesive layer may be any thickness that provides the desired adhesive strength, for example, 10 μm or more, 25 μm or more, or 50 μm or more. The mesh sheet surface has irregularities due to openings and non-openings. By ensuring that the thickness of the adhesive layer is equal to or greater than a predetermined value, the irregularities on the mesh sheet surface can be smoothed out. This improves adhesion between the adhesive sheet for electronic components and the substrate or chip to be processed, thereby suppressing chipping during water jet laser processing. Furthermore, if the adhesive layer is too thin, adhesion to the mesh sheet may be reduced. Furthermore, if the adhesive layer is too thin, oxygen inhibition from the mesh sheet side of the adhesive layer may result in poor curing. On the other hand, the thickness of the adhesive layer is, for example, 200 μm or less. If the adhesive layer is too thick, water permeability may be reduced.

[0081] As illustrated in Figure 2, when the mesh sheet is a mesh fabric 1A, the thickness T of the adhesive layer 2 is the length from the reference plane S to the outermost surface of the adhesive layer 2 on the mesh fabric 1A side, where the reference plane S is the outermost surface of the mesh fabric 1A on the adhesive layer 2 side.

[0082] (3) Method for forming adhesive layer As a method for forming the adhesive layer, for example, a method of applying an adhesive composition onto a separator can be mentioned. After the adhesive layer is formed, a mesh sheet is placed on the adhesive layer to obtain an adhesive tape for processing electronic components having the mesh sheet, adhesive layer, and separator in this order.

[0083] 3. Mesh Sheet The mesh sheet in this embodiment is a member that supports the adhesive layer.

[0084] Examples of the mesh sheet include a mesh fabric and a punched sheet, which is a sheet that has been punched with holes.

[0085] (1) Mesh Fabric Figures 3(a) to 3(c) are schematic plan and cross-sectional views illustrating an example of a mesh fabric in the adhesive tape for electronic component processing of this embodiment. Figure 3(b) is an enlarged view of Figure 3(a), and Figure 3(c) is a cross-sectional view of Figure 3(b). As shown in Figures 3(a) to 3(c), mesh fabric 1A is composed of warp yarns 21 and weft yarns 22. In plan view, mesh fabric 1A has openings 23 surrounded by warp yarns 21 and weft yarns 22, and non-openings 24 that have warp yarns 21 and weft yarns 22 and are other than openings 23. In Figures 3(a) to 3(c), a1 indicates the diameter of warp yarns 21, a2 indicates the diameter of weft yarns 22, b1 indicates the opening between warp yarns 21, and b2 indicates the opening between weft yarns 22.

[0086] The mesh fabric material preferably has high transmittance to the wavelength of the laser used in water jet laser processing. Examples of mesh fabric materials include chemical fibers, natural fibers, and inorganic fibers. Examples of chemical fiber materials include polyolefin, polyester, polyamide, polycarbonate, acrylic resin, polyvinyl chloride, polyurethane, polystyrene, styrene-ethylene-butene copolymer, styrene-ethylene-pentene copolymer, rayon, and cellulose acetate. Examples of polyolefins include polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), and ionomer. Examples of polyesters include polyethylene terephthalate. Examples of polyamides include nylon 6, nylon 6,6, nylon 12, and aramid. Examples of natural fiber materials include cotton, silk, and wool. Examples of inorganic fibers include glass fiber and carbon fiber. These may be used alone or in combination.

[0087] The weaving method of the mesh fabric is not particularly limited, and examples thereof include plain weave, twill weave, and satin weave.

[0088] The warp and weft threads may each be monofilaments or multifilaments, with monofilaments being preferred because they are less likely to break during water jet laser processing.

[0089] The average diameter of the yarn is, for example, 60 μm or more, or may be 80 μm or more, or 100 μm or more. The average diameter of the yarn is, for example, 1000 μm or less, or 500 μm or less, or 300 μm or less. That is, the average diameter of the yarn is, for example, 60 μm or more and 1000 μm or less, or 80 μm or more and 500 μm or less, or 100 μm or more and 300 μm or less. If the average diameter is too small, the strength of the mesh sheet may decrease, making it difficult to handle. On the other hand, if the average diameter is too large, water permeability may be impaired. When the yarn is a multifilament, the average diameter of the yarn refers to the average diameter of the multifilament.

[0090] Here, the average yarn diameter is the arithmetic mean value of the diameters of 10 randomly selected warp yarns and 10 randomly selected weft yarns. The warp diameter and weft diameter are each measured using a digital microscope. The digital microscope used can be a Keyence VHX-2000 Digital Microscope.

[0091] The opening rate of the mesh fabric is, for example, 10% or more, 20% or more, or 30% or more. The opening rate of the mesh fabric is, for example, 80% or less, 70% or less, or 60% or less. That is, the opening rate of the mesh fabric is, for example, 10% or more and 80% or less, 20% or more and 70% or less, or 30% or more and 60% or less. If the opening rate is too small, water permeability may be impaired. On the other hand, if the opening rate is too large, adhesion to the adhesive layer may be reduced.

[0092] The opening ratio B (%) of the mesh fabric is expressed by the following formula: B = [C / (C + A)] ２ ×100 In the above formula, A is the average diameter of the yarn (μm), and C is the average opening between the yarns (μm).

[0093] The average opening between the threads is preferably smaller than the chip size, for example, on the order of millimeters or less. The average opening between the threads is, for example, 500 μm or less, or may be 200 μm or less, or 100 μm or less. The average opening between the threads is, for example, 1 μm or more, or may be 5 μm or more, or may be 10 μm or more. That is, the average opening between the threads is, for example, 1 μm or more and 500 μm or less, or 5 μm or more and 200 μm or less, or may be 10 μm or more and 100 μm or less. If the average opening is too small, water permeability may be impaired. On the other hand, if the average opening is too large, adhesion to the adhesive layer may be reduced.

[0094] The average inter-yarn shed is the arithmetic mean value of sheds between warp yarns and sheds between weft yarns at 10 randomly selected locations. The sheds between warp yarns and the sheds between weft yarns are measured using a digital microscope. As the digital microscope, a "Digital Microscope VHX-2000" manufactured by Keyence Corporation can be used.

[0095] When measuring the diameter of the warp yarns, the diameter of the weft yarns, the opening between the warp yarns, and the opening between the weft yarns, the adhesive layer is removed from the adhesive tape for electronic component processing, and the mesh sheet is taken out. A method for removing the adhesive layer includes dissolving the adhesive layer with a solvent. The solvent used in forming the adhesive layer can be used as the solvent.

[0096] (2) Punching Sheet The material of the punching sheet preferably has a high transmittance for the wavelength of the laser used in water jet laser processing. Examples of the material of the punching sheet include resin. The resin is not particularly limited as long as it can be processed to punch holes.

[0097] The shape of the holes in a plan view is not particularly limited, and examples thereof include a square, a rectangle, a circle, an ellipse, a square with rounded corners, a rectangle with rounded corners, and a hexagon. The arrangement of the holes is not particularly limited.

[0098] The opening ratio of the punched sheet is, for example, 10% or more, 20% or more, or 30% or more. The opening ratio of the punched sheet is, for example, 80% or less, 70% or less, or 60% or less. That is, the opening ratio of the punched sheet is, for example, 10% or more and 80% or less, 20% or more and 70% or less, or 30% or more and 60% or less. If the opening ratio is too small, water permeability may be impaired. On the other hand, if the opening ratio is too large, adhesion to the adhesive layer may be reduced.

[0099] The aperture ratio of the punched sheet is calculated appropriately depending on the planar shape of the holes, the size of the holes, the hole pitch, the hole arrangement, and the like.

[0100] The hole size is preferably smaller than the chip size, for example, on the order of millimeters or less. The hole size is, for example, 500 μm or less, or may be 200 μm or less, or 100 μm or less. The hole size is, for example, 1 μm or more, or may be 5 μm or more, or may be 10 μm or more. That is, the hole size is, for example, 1 μm or more and 500 μm or less, or 5 μm or more and 200 μm or less, or may be 10 μm or more and 100 μm or less. If the hole size is too small, water permeability may be impaired. On the other hand, if the hole size is too large, adhesion to the adhesive layer may be reduced.

[0101] The hole size is the arithmetic average of 10 randomly selected holes. The hole size is defined according to the shape of the hole in plan view. For example, the hole size refers to the diameter in the case of a circle, the major axis in the case of an ellipse, the diagonal length in the case of a square or rectangle, and the length of the longest diagonal in the case of a hexagon. The hole size is measured using a digital microscope. As the digital microscope, the "Digital Microscope VHX-2000" manufactured by Keyence Corporation can be used.

[0102] When measuring the size of the hole, the adhesive layer is removed from the adhesive tape for processing electronic components, and the mesh sheet is taken out. The method for removing the adhesive layer is as described above.

[0103] (3) Characteristics of the Mesh Sheet The light transmittance of the mesh sheet is not particularly limited, and may be, for example, 50% or more, 70% or more, or even 90% or more. The upper limit of the light transmittance of the mesh sheet is not particularly limited. If the light transmittance of the mesh sheet is high within the above range, reflection of light by the mesh sheet can be suppressed when the adhesive tape for electronic component processing is irradiated with light from the mesh sheet side to cure the adhesive layer. This can suppress poor curing of the adhesive layer.

[0104] The optical transmittance of the mesh sheet is the transmittance of light used when dicing a substrate to be processed using the adhesive tape for electronic component processing. For example, when ultraviolet light is used, as mentioned above, the ultraviolet irradiation device often uses a high-pressure mercury lamp or an electrodeless lamp that reproduces the spectrum of a high-pressure mercury lamp. The dominant wavelength of a high-pressure mercury lamp is 365 nm. Therefore, in this case, the optical transmittance of the mesh sheet is the transmittance of a wavelength of 365 nm.

[0105] The thickness of the mesh sheet is not particularly limited as long as it can support the adhesive layer. The thickness of the mesh sheet is, for example, 60 μm or more, or may be 80 μm or more, or 100 μm or more. The thickness of the mesh sheet is, for example, 1000 μm or less, or may be 500 μm or less, or may be 300 μm or less. That is, the thickness of the mesh sheet is, for example, 60 μm or more and 1000 μm or less, or may be 80 μm or more and 500 μm or less, or may be 100 μm or more and 300 μm or less.

[0106] The thickness of the mesh sheet is measured using a thickness gauge such as a dial thickness gauge or a digital thickness gauge, and the arithmetic mean value of the thicknesses at 10 randomly selected points is used.

[0107] When measuring the thickness of the mesh sheet, the adhesive layer is removed from the adhesive tape for processing electronic components, and the mesh sheet is taken out. The method for removing the adhesive layer is as described above.

[0108] 4. Other Configurations The adhesive tape for processing electronic components of this embodiment may have other configurations as needed in addition to the mesh sheet and adhesive layer described above.

[0109] The adhesive tape for processing electronic parts of this embodiment may have a separator on the surface of the adhesive layer opposite to the mesh sheet.

[0110] 5. Uses The adhesive tape for electronic component processing of this embodiment can be used as a dicing tape. In particular, the adhesive tape for electronic component processing of this embodiment can be suitably used as a dicing tape when dicing a substrate to be processed by laser processing. In particular, the adhesive tape for electronic component processing of this embodiment can be suitably used as a dicing tape when dicing a substrate to be processed by water jet laser processing.

[0111] II. Second Embodiment A second embodiment of the adhesive tape for electronic component processing according to the present disclosure is an adhesive tape for electronic component processing having a mesh sheet and a photocurable adhesive layer disposed on a first surface of the mesh sheet in contact with the mesh sheet, wherein when irradiated with light using a black light under atmospheric conditions, the adhesive strength to a glass plate before light irradiation is 5 N / 25 mm or more, and the adhesive strength to a glass plate after light irradiation is less than 0.7 N / 25 mm, and the adhesive strength reduction rate represented by the following formula (1) is 92% or more. Adhesive strength reduction rate (%) = [1 - (adhesive strength to glass plate after light irradiation / adhesive strength to glass plate before light irradiation)] × 100 (2)

[0112] Fig. 1 is a schematic cross-sectional view illustrating an example of an adhesive tape for electronic component processing according to this embodiment. As illustrated in Fig. 1, the adhesive tape for electronic component processing 10 includes a mesh sheet 1 and a photocurable adhesive layer 2 disposed on a first surface of the mesh sheet 1 in contact with the mesh sheet 1.

[0113] In this embodiment, the photocurable adhesive layer is cured by light irradiation, and its adhesive strength is reduced. If the adhesive layer is sufficiently cured even in the atmosphere and its adhesive strength is reduced, the adhesive strength reduction rate will be large. On the other hand, if the adhesive layer is not sufficiently cured in the atmosphere, the adhesive strength reduction rate will be small. Therefore, the larger the adhesive strength reduction rate, the more effective it is in suppressing curing inhibition by oxygen.

[0114] Therefore, in this embodiment, by ensuring that the adhesive strength reduction rate is equal to or greater than a predetermined value, it is possible to suppress curing inhibition due to oxygen. As a result, the adhesive layer can be easily peeled off after light irradiation, which prevents chip cracking or chipping when the adhesive tape for processing electronic components is peeled off. Furthermore, since there is no need for nitrogen purging during light irradiation and light irradiation can be performed in the atmosphere, it is possible to reduce costs and improve workability.

[0115] Hereinafter, each component of the adhesive tape for processing electronic parts according to this embodiment will be described.

[0116] 1. Properties of the adhesive tape for electronic component processing (1) Adhesion strength to glass plate In the adhesive tape for electronic component processing of this embodiment, the adhesion strength to a glass plate before light irradiation is the same as the adhesion strength to a glass plate before light irradiation in the above-mentioned first embodiment.

[0117] Furthermore, when the adhesive tape for electronic component processing of this embodiment is irradiated with light under atmospheric conditions using a black light, the adhesive strength to a glass plate after light irradiation is less than 0.7 N / 25 mm, and may be 0.3 N / 25 mm or less, or may be 0.1 N / 25 mm or less. Having the adhesive strength within the above range allows the adhesive tape for electronic component processing to be easily peeled off after light irradiation. Meanwhile, the lower limit of the adhesive strength to a glass plate after light irradiation is, for example, 0.01 N / 25 mm or more, since it is necessary to hold the chip during transport.

[0118] The adhesive strength to a glass plate after light irradiation is measured by the following method. First, in accordance with Method 1 of the test method of JIS Z0237:2022 (Test method for adhesive tapes and adhesive sheets) (a test method in which the tape and sheet are peeled at 180° from a stainless steel test plate at a temperature of 23°C and a humidity of 50%), a 25 mm wide test piece is taken from the adhesive tape for electronic component processing and the test piece is attached to a glass plate. The glass plate used is float glass (size 150 mm x 70 mm, thickness 2 mm) manufactured by Osaka Glass Industry Co., Ltd. Next, using a black light UV irradiator "UVI-1200MB" manufactured by Omiya Kogyo Co., Ltd., an integrated light intensity of 500 mJ / cm at a wavelength of 365 nm is measured. ２The UV lamp of the UV irradiator is a black light blue lamp "FPL36BLB" manufactured by Sankyo Electric Co., Ltd. The peak wavelength of the black light blue lamp is around 360 nm. The illuminance of the black light UV irradiator is 8 mW / cm. ２ Next, in accordance with Method 1 of the test methods of JIS Z0237:2022 (Test methods for adhesive tapes and adhesive sheets) (a test method in which the tape or sheet is peeled off at an angle of 180° from a stainless steel test plate at a temperature of 23°C and a humidity of 50%), the adhesive strength to the glass plate is measured by peeling off the test piece in the length direction under conditions of a peel angle of 180° and a peel speed of 300 mm / min.

[0119] In addition, as the light irradiation device, a light source that irradiates light of a single wavelength may be used instead of a light source that irradiates light of a wide wavelength range, such as a high-pressure mercury lamp or an electrodeless lamp that reproduces the spectrum of a high-pressure mercury lamp. Therefore, in this embodiment, when measuring the adhesive strength to the glass plate after light irradiation, a black light was used as a light source that irradiates light of a single wavelength.

[0120] In addition, when it is difficult to use the black light UV irradiation machine "UVI-1200MB" manufactured by Omiya Kogyo Co., Ltd. and the black light blue lamp "FPL36BLB" manufactured by Sankyo Denki Co., Ltd., a black light with a peak wavelength of 365 nm and an illuminance of 8 mW / cm is used. ２ Alternatively, light may be irradiated using a UV irradiator.

[0121] (2) Adhesive Strength Reduction Rate In the adhesive tape for electronic component processing of this embodiment, when irradiated with light in the atmosphere using an electrodeless lamp, the adhesive strength reduction rate represented by the following formula (2) is 92% or more, or may be 95% or more, or may be 99% or more. When the adhesive strength reduction rate is equal to or greater than a predetermined value, curing inhibition due to oxygen can be suppressed. On the other hand, as described above, the larger the adhesive strength reduction rate, the more effective it is in suppressing curing inhibition due to oxygen, so the upper limit of the adhesive strength reduction rate is not particularly limited.

[0122] Adhesive strength reduction rate (%) = [1 - (adhesive strength to glass plate after light irradiation / adhesive strength to glass plate before light irradiation)] × 100 (2)

[0123] The method for measuring the adhesive strength to the glass plate before light irradiation and the method for measuring the adhesive strength to the glass plate after light irradiation are as described above.

[0124] The method for controlling the adhesive strength reduction rate is the same as the method for controlling the adhesive strength reduction rate in the first embodiment.

[0125] 2. Adhesive Layer The adhesive layer in this embodiment is the same as the adhesive layer in the first embodiment, except for the material of the adhesive layer.

[0126] The material of the adhesive layer in this embodiment is the same as the material of the adhesive layer in the first embodiment, except for the polymerization initiator.

[0127] As the polymerization initiator, a general photopolymerization initiator can be used. Among them, an oxime ester polymerization initiator is preferred. Specific examples of the oxime ester polymerization initiator are the same as those of the oxime ester polymerization initiator in the first embodiment.

[0128] Oxime ester polymerization initiators generate active species with high reactivity, which can enhance curing properties. Furthermore, oxime ester polymerization initiators are highly reactive because their bonds are easily cleaved by light irradiation to generate radicals. Therefore, the adhesive strength to glass plates after light irradiation in the atmosphere can be reduced, and the adhesive strength reduction rate can be increased.

[0129] The content of the oxime ester polymerization initiator in the adhesive layer may be, for example, 0.5 parts by mass or more, or 5 parts by mass or more, per 100 parts by mass of the resin (main adhesive). On the other hand, the content may be, for example, 20 parts by mass or less, or 10 parts by mass or less, per 100 parts by mass of the resin (main adhesive). That is, the content may be, for example, 0.5 parts by mass or more, or 20 parts by mass or less, or 5 parts by mass or more, or 10 parts by mass or less, per 100 parts by mass of the resin (main adhesive). If the content is too low, the polymerization reaction of the photocurable compound may not occur sufficiently, resulting in excessively high adhesive strength of the adhesive layer after light irradiation, making it difficult to achieve peelability. On the other hand, if the content of the polymerization initiator is too high, the cohesive strength may decrease, potentially causing adhesive residue.

[0130] Furthermore, the oxime ester polymerization initiator may be combined with another polymerization initiator. In this case, the same effects as those described above are also achieved. The other polymerization initiator is not particularly limited, but as described in the first embodiment, an acylphosphine oxide polymerization initiator is preferred. Specific examples of the acylphosphine oxide polymerization initiator are the same as those of the acylphosphine oxide polymerization initiator in the first embodiment.

[0131] In this case, the total content of the oxime ester polymerization initiator and other polymerization initiators in the adhesive layer may be, for example, 0.5 parts by mass or more, or 5 parts by mass or more, per 100 parts by mass of the resin (main adhesive). On the other hand, the total content may be, for example, 20 parts by mass or less, or 10 parts by mass or less, per 100 parts by mass of the resin (main adhesive). That is, the total content may be, for example, 0.5 parts by mass or more, or 20 parts by mass or less, or 5 parts by mass or more, or 10 parts by mass or less, per 100 parts by mass of the resin (main adhesive). If the total content is too low, the polymerization reaction of the photocurable compound may not occur sufficiently, resulting in excessively high adhesive strength of the adhesive layer after light irradiation, which may make it impossible to achieve peelability. On the other hand, if the total content is too high, the cohesive strength may decrease, potentially causing adhesive residue.

[0132] 3. Mesh Sheet The mesh sheet in this embodiment is the same as the mesh sheet in the first embodiment.

[0133] 4. Other Configurations The adhesive tape for electronic component processing of this embodiment may have other configurations, as necessary, in addition to the mesh sheet and adhesive layer described above. The other configurations are the same as those in the first embodiment.

[0134] 5. Uses The uses of the adhesive tape for processing electronic parts of this embodiment are the same as those of the first embodiment.

[0135] B. Manufacturing Method of Electronic Components The manufacturing method of electronic components in the present disclosure includes an attachment step of attaching the above-described adhesive tape for electronic component processing to a first surface of a workpiece substrate, a dicing step of dividing the workpiece substrate into a plurality of chips, an irradiation step of irradiating the adhesive layer of the adhesive tape for electronic component processing with light to harden it, and a peeling step of peeling the adhesive tape for electronic component processing from the chips.

[0136] 4(a) to 4(f) are process diagrams illustrating an example of a method for manufacturing electronic components according to the present disclosure. First, as shown in FIG. 4(a), a bonding process is performed in which a first surface of the adhesive tape 10 for electronic component processing is bonded to a ring frame 31, and then a workpiece substrate 11 is bonded to the first surface of the adhesive tape 10 for electronic component processing. Next, as shown in FIG. 4(b), a dicing process is performed in which the workpiece substrate 11 is divided into chips 12. Next, as shown in FIG. 4(c), an expanding process is performed in which the adhesive tape 10 for electronic component processing is stretched to increase the spacing between the chips 12. Next, as shown in FIG. 4(d), an irradiation process is performed in which light 32 is irradiated onto the adhesive layer of the adhesive tape 10 for electronic component processing from the mesh sheet side to harden the adhesive layer and thereby reduce its adhesive strength. Next, as shown in FIG. 4(e), a pick-up process is performed in which the chips 12 are peeled off the adhesive tape 10 for electronic component processing and picked up. This pick-up process is the peeling process. Next, as shown in FIG. 4( f ), a mounting (die bonding) step is carried out in which the picked-up chip 12 is bonded to a substrate 30 .

[0137] 5(a) to 5(e) are process diagrams illustrating another example of a method for manufacturing electronic components according to the present disclosure. First, as shown in FIG. 5(a), an adhesive tape 10 for electronic component processing is attached to a ring frame 31, and then a substrate 11 to be processed is attached to the adhesive tape 10. Next, as shown in FIG. 5(b), a dicing process is performed to divide the substrate 11 into chips 12. Next, as shown in FIG. 5(c), a transfer tape 40 is attached to the side of the chip 12 opposite the adhesive tape 10 for electronic component processing. Then, as shown in FIG. 5(d), an irradiation process is performed in which the photocurable adhesive layer of the adhesive tape 10 for electronic component processing is irradiated with light from the mesh sheet side to harden it, thereby reducing its adhesive strength. Next, as shown in FIG. 5(e), a transfer process is performed in which the adhesive tape 10 for electronic component processing is peeled off from the chip 12 and the ring frame 31, and the chip 12 and the ring frame 31 are transferred to the transfer tape 40. This transfer process is the peeling process.

[0138] In the present disclosure, the use of the above-described adhesive tape for electronic component processing can suppress curing inhibition due to oxygen during the irradiation process. As a result, the adhesive layer of the adhesive tape for electronic component processing can be easily peeled off during the peeling process, thereby suppressing chip cracking and chipping. Furthermore, since the irradiation process does not require nitrogen purging and can be carried out under atmospheric conditions, costs can be reduced and workability can be improved.

[0139] A general method can be applied to each step in the method for manufacturing an electronic component according to the present disclosure.

[0140] In particular, in the dicing step, it is preferable to divide the substrate into a plurality of chips by a laser guided by a water jet. General conditions can be adopted for the water jet laser processing.

[0141] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure.

[0142] The present disclosure will be further described below with reference to examples and comparative examples.

[0143] [Production Example 1] A pressure-sensitive adhesive composition was prepared by diluting and thoroughly dispersing 100 parts by mass of a main adhesive agent (acrylic acid copolymer), 50 parts by mass of urethane acrylate (ultraviolet-curable compound, 9 functional groups, molecular weight 4100, active content 65%), 7.5 parts by mass of a polymerization initiator (acylphosphine oxide-based, "Omnirad 819" manufactured by IGM Resins), and 3 parts by mass of a crosslinking agent (isocyanate-based curing agent (tolylene diisocyanate (TDI)-based adduct type (trimethylolpropane adduct)), solid content 75%) with a mixed solvent of toluene and methyl ethyl ketone (mass ratio 1:1).

[0144] The pressure-sensitive adhesive composition was applied to a polyethylene terephthalate (PET) separator ("PET50x1-M-J2" manufactured by Nippa Corporation, thickness 50 μm) so that the thickness after drying would be 50 μm, and the applied composition was dried in an oven at 110°C for 3 minutes to form a pressure-sensitive adhesive layer.

[0145] A nylon mesh sheet ("NB90" manufactured by NBC Meshtec Co., Ltd.) was laminated onto the adhesive layer, and then aging was carried out at 40°C for 3 days to prepare an adhesive tape for processing electronic components.

[0146] [Production Examples 2 to 13] Pressure-sensitive adhesive tapes for processing electronic components were produced in the same manner as in Production Example 1, except that the type of polymerization initiator and the content of the polymerization initiator relative to 100 parts by mass of the main adhesive agent (acrylic acid copolymer) were changed as shown in Table 1 below.

[0147] The polymerization initiators in Table 1 are as follows: Acylphosphine oxide type: "Omnirad 819" manufactured by IGM Resins α-Aminoalkylphenone type 1: "Omnirad 369" manufactured by IGM Resins α-Aminoalkylphenone type 1: "Omnirad 907" manufactured by IGM Resins α-Hydroxyalkylphenone type: "Omnirad 184" manufactured by IGM Resins Oxime ester type 1: "Irgacure OXE01" manufactured by BASF Japan Oxime ester type 2: "Irgacure OXE02" manufactured by BASF Japan

[0148] [Evaluation] (1) Adhesion to Glass Plate The adhesive strength of the adhesive tape for processing electronic components to a glass plate before and after light irradiation was measured by the above-mentioned measurement method.

[0149] (2) Decrease in Adhesion Strength The decrease in adhesion strength represented by the above formula (1) or (2) was calculated.

[0150] (3) Pickup properties (3-1) Electrodeless lamp An adhesive tape for electronic component processing was attached to a ring frame for 6-inch wafers, and a 6-inch silicon wafer having a thickness of 100 μm was adhered and fixed to the adhesive tape for electronic component processing. Using a water jet laser processing dicing device ("Laser Microjet" manufactured by SYNOVA), the silicon wafer was divided into 10 mm square chips under conditions of a cutting speed of 100 mm / s, a laser wavelength of 532 nm, a water jet diameter of 40 μm, and a water pressure of 250 Bar. Next, using an electrodeless UV lamp system manufactured by Heraeus, an integrated light intensity of 500 mJ / cm at a wavelength of 365 nm was applied to the adhesive layer of the adhesive tape for electronic component processing from the mesh sheet side. ２ The electrodeless UV lamp system used an H bulb manufactured by Heraeus GmbH. Next, the chip was peeled off by hand. The presence or absence of cracks in the chip was then visually observed.

[0151] (3-2) Black Light An adhesive tape for electronic component processing was attached to a ring frame for 6-inch wafers, and a 6-inch silicon wafer with a thickness of 100 μm was adhered and fixed to the adhesive tape for electronic component processing. Using a water jet laser processing dicing device ("Laser Microjet" manufactured by SYNOVA), the silicon wafer was divided into 10 mm square chips under conditions of a cutting speed of 100 mm / s, a laser wavelength of 532 nm, a water jet diameter of 40 μm, and a water pressure of 250 Bar. Next, using a black light UV irradiator "UVI-1200MB" manufactured by Omiya Kogyo Co., Ltd., a cumulative light intensity of 500 mJ / cm at a wavelength of 365 nm was applied to the adhesive layer of the adhesive tape for electronic component processing from the mesh sheet side. ２ The UV lamp of the UV irradiator was a black light blue lamp "FPL36BLB" manufactured by Sankyo Electric Co., Ltd. Next, the chip was peeled off by hand. Then, the presence or absence of cracks in the chip was visually observed.

[0152] The pickup property was evaluated according to the following criteria: A: No cracks were observed. B: Cracks were observed.

[0153]

[0154] As in Production Examples 1 to 6, when light was irradiated under atmospheric conditions using an electrodeless lamp, if the adhesive strength reduction rate was a predetermined value or more, it was confirmed that the pickup properties were good and that curing inhibition due to oxygen was suppressed. Similarly, as in Production Examples 3, 5, and 6, when light was irradiated under atmospheric conditions using a black light, if the adhesive strength reduction rate was a predetermined value or more, it was confirmed that the pickup properties were good and that curing inhibition due to oxygen was suppressed. On the other hand, in Production Examples 7 to 13, when light was irradiated under atmospheric conditions using an electrodeless lamp and when light was irradiated under atmospheric conditions using a black light, the adhesive strength reduction rate was small, and therefore the pickup properties were poor.

[0155] The present disclosure provides the following inventions: [1] An adhesive tape for electronic component processing, comprising a mesh sheet and a photocurable adhesive layer disposed on a first surface of the mesh sheet in contact with the mesh sheet, wherein, when irradiated with light from an electrodeless lamp in the atmosphere, the adhesive tape has an adhesive strength to a glass plate of 5 N / 25 mm or more before light irradiation and an adhesive strength to a glass plate of less than 0.7 N / 25 mm after light irradiation, and an adhesive strength reduction rate expressed by the following formula (1) of 92% or more: Adhesive strength reduction rate (%) = [1 - (adhesive strength to glass plate after light irradiation / adhesive strength to glass plate before light irradiation)] × 100 (1) [2] An adhesive tape for electronic component processing, comprising a mesh sheet and a photocurable adhesive layer disposed on a first surface of the mesh sheet and in contact with the mesh sheet, wherein, when irradiated with light using a black light under atmospheric pressure, the adhesive strength to glass plate before light irradiation is 5 N / 25 mm or more and the adhesive strength to glass plate after light irradiation is less than 0.7 N / 25 mm, and the adhesive strength reduction rate, as expressed by the following formula (2), is 92% or more. Adhesive strength reduction rate (%) = [1 - (adhesive strength to glass plate after light irradiation / adhesive strength to glass plate before light irradiation)] × 100 (2) [3] The adhesive tape for electronic component processing according to [1], wherein the adhesive layer contains an adhesive main agent, a photocurable compound, and an acylphosphine oxide-based polymerization initiator, and the content of the acylphosphine oxide-based polymerization initiator in the adhesive layer is 7.5 parts by mass or more per 100 parts by mass of the adhesive main agent. [4] The adhesive tape for electronic component processing according to [1], wherein the adhesive layer contains an adhesive main agent, a photocurable compound, an acylphosphine oxide-based polymerization initiator, and an α-hydroxyalkylphenone-based polymerization initiator. [5] The adhesive tape for electronic component processing according to [1] or [2], wherein the adhesive layer contains an adhesive main agent, a photocurable compound, and an oxime ester-based polymerization initiator.[6] A method for manufacturing an electronic component, comprising: a bonding step of bonding the adhesive tape for electronic component processing according to any one of [1] to [5] to a first surface of a workpiece substrate, a dicing step of dividing the workpiece substrate into a plurality of chips, an irradiation step of irradiating the adhesive layer of the adhesive tape for electronic component processing with light to harden it, and a peeling step of peeling the adhesive tape for electronic component processing from the chips. [7] A method for manufacturing an electronic component according to [6], wherein in the dicing step, the workpiece substrate is divided into a plurality of chips by a laser guided by a water jet.

[0156] 1... Mesh sheet 2... Adhesive layer 10... Adhesive tape for electronic component processing

Claims

1. An adhesive tape for electronic component processing, comprising a mesh sheet and a photocurable adhesive layer disposed on a first surface of the mesh sheet in contact with the mesh sheet, wherein when irradiated with light from an electrodeless lamp under atmospheric conditions, the adhesive tape has an adhesive strength to a glass plate before light irradiation of 5 N / 25 mm or more and an adhesive strength to a glass plate after light irradiation of less than 0.7 N / 25 mm, and an adhesive strength reduction rate represented by the following formula (1) of 92% or more: Adhesive strength reduction rate (%) = [1 - (adhesive strength to glass plate after light irradiation / adhesive strength to glass plate before light irradiation)] x 100 (1) 2. An adhesive tape for electronic component processing, comprising a mesh sheet and a photocurable adhesive layer disposed on a first surface of the mesh sheet in contact with the mesh sheet, wherein when irradiated with light using a black light under atmospheric conditions, the adhesive tape has an adhesive strength to a glass plate before light irradiation of 5 N / 25 mm or more and an adhesive strength to a glass plate after light irradiation of less than 0.7 N / 25 mm, and an adhesive strength reduction rate represented by the following formula (2) of 92% or more: Adhesive strength reduction rate (%) = [1 - (adhesive strength to glass plate after light irradiation / adhesive strength to glass plate before light irradiation)] x 100 (2) 3. The adhesive tape for processing electronic components according to claim 1, wherein the adhesive layer contains an adhesive base, a photocurable compound, and an acylphosphine oxide-based polymerization initiator, and the content of the acylphosphine oxide-based polymerization initiator in the adhesive layer is 7.5 parts by mass or more per 100 parts by mass of the adhesive base.

4. The adhesive tape for processing electronic components according to claim 1, wherein the adhesive layer contains an adhesive base, a photocurable compound, an acylphosphine oxide-based polymerization initiator, and an α-hydroxyalkylphenone-based polymerization initiator.

5. The adhesive tape for processing electronic components according to claim 1 or 2, wherein the adhesive layer contains a main adhesive agent, a photocurable compound, and an oxime ester-based polymerization initiator.

6. A method for manufacturing electronic components, comprising: an application step of applying the adhesive tape for electronic component processing according to claim 1 or 2 to a first surface of a substrate to be processed; a dicing step of dividing the substrate to be processed into a plurality of chips; an irradiation step of irradiating the adhesive layer of the adhesive tape for electronic component processing with light to harden it; and a peeling step of peeling the adhesive tape for electronic component processing from the chips.

7. The method for manufacturing electronic components according to claim 6, wherein in the dicing step, the workpiece substrate is divided into a plurality of chips by a laser guided by a water jet.

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