KR20210097028A - Masking material - Google Patents

Abstract

An object is to provide a masking material that is less prone to produce cutting dust when used in a dicing step and can be easily peeled after dicing while it is hardly peeled in dicing. The masking material comprises: an adhesive layer formed of an activate energy ray-curable adhesive; and a base material. The activate energy ray-curable adhesive includes a base polymer which is a polymer obtained by polymerization of a monomer composition including 5-20 mol% of a (meth)acrylic monomer having at least one alkyl group selected from a group consisting of a methyl group and an ethyl group. The masking material and a silicon wafer are diced in a state in which the masking material is attached to the silicon wafer, and then the adhesive layer is cured by exposure to activate energy rays. After the dicing, the surface roughness Sa of a dicing cut section of the adhesive layer is equal to or smaller than 3 μm.

Description

Masking material {MASKING MATERIAL}

The present invention relates to a masking material. More specifically, it relates to a masking material used when protecting a part of an electronic component provided in a predetermined manufacturing process.

When providing an electronic component to a predetermined manufacturing process, in order to protect a weak part, a part which does not require a process, etc., masking the said part with a masking material is performed. At this time, the masking surface may have convex parts, such as a bump, and it may become an uneven|corrugated shape, and the masking material which can adhere with respect to a convex part with good followability|trackability is calculated|required.

On the other hand, as a manufacturing process of an electronic component, the process (dicing process) of miniaturizing the precursor of the electronic component processed in a large area is known. Also in this dicing process, an electronic component (precursor of an electronic component) has a convex part as mentioned above, and the surface which has this convex part may be masked.

However, when an electronic component provided with a masking material is subjected to a dicing process, chips are generated from the cut surface, and the chips contaminate the electronic part, or a process after dicing, such as a sputtering process, and There are problems such as inconvenience in the etching process. As a technique to solve such a problem, the technique using the masking tape provided with the adhesive layer which can be hardened by ultraviolet irradiation is proposed (patent documents 1, 2). In the said technique, after sticking a masking tape to an electronic component precursor, an adhesive layer is hardened by ultraviolet irradiation. Thereby, generation|occurrence|production of the chips at the time of dicing can be suppressed. However, the sputtering process after a dicing process, and an etching process process WHEREIN: The process with respect to a to-be-adhered body may not fully be able to be performed by the chips (whisker) which arose in the base film.

Japanese Patent Laid-Open No. 2013-123003 Japanese Patent Laid-Open No. 2010-212310

The present invention has been made in order to solve the above conventional problems, and the object thereof is that it can follow the concave-convex shape of the surface to be masked well, it is difficult to generate chips when subjected to a dicing process, and the die An object of the present invention is to provide a masking material that is difficult to peel off during dicing and can be easily peeled off after dicing.

The masking material of the present invention includes a pressure-sensitive adhesive layer formed of an active energy ray-curable pressure-sensitive adhesive and a base material, and the base polymer of the active energy ray-curable pressure-sensitive adhesive has at least one alkyl group selected from the group consisting of a methyl group and an ethyl group. It is a polymer obtained by superposing|polymerizing the monomer composition containing 5 mol% - 20 mol% of a (meth)acrylic-type monomer. This masking material is affixed to a silicon wafer, and the surface roughness Sa of the dicing cut surface of the adhesive layer after dicing the masking material and the silicon wafer in the state which irradiates an active energy ray and hardened|cured the adhesive layer is 3 micrometers or less.

In one embodiment, the said monomer composition further contains a hydroxyl-containing monomer. The content rate in the monomer composition of this hydroxyl-containing monomer is 10 mol% - 30 mol%.

In one embodiment, the base polymer is a polymer having a carbon-carbon double bond.

In one embodiment, the storage elastic modulus in 22 degreeC after active energy ray irradiation of the said adhesive layer is 30 Mpa - 300 Mpa.

In one embodiment, the breaking strength in 22 degreeC after active energy ray irradiation of the said adhesive layer is 7 MPa - 15 MPa.

In one embodiment, the said masking material is used for a semiconductor manufacturing process.

According to the present invention, it is possible to follow the concave-convex shape of the surface to be masked well, it is difficult to generate chips when subjected to a dicing process, and it is difficult to peel off during dicing, but it can be easily peeled off after dicing. It is possible to provide a masking material. The masking material of this invention can be cut|disconnected (dicing) in a flatter state. Therefore, the contamination of the to-be-adhered body by cuttings can be prevented more.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the masking material by one Embodiment of this invention.

A. Overall composition of masking material

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the masking material by one Embodiment of this invention. The masking material 100 includes an adhesive layer 20 . In one embodiment, as shown in FIG. 1, the masking material 100 is equipped with the base material 10 and the adhesive layer 20 arrange|positioned at least on one side of the base material 10. The pressure-sensitive adhesive layer contains an active energy ray-curable pressure-sensitive adhesive, and the pressure-sensitive adhesive layer is curable by irradiation with an active energy ray. The base polymer of this active energy ray-curable adhesive is obtained by polymerizing a monomer composition containing 5 mol% to 20 mol% of a (meth)acrylic monomer having at least one alkyl group selected from the group consisting of a methyl group and an ethyl group. It is a polymer. Examples of active energy rays include gamma rays, ultraviolet rays, visible rays, infrared rays (hot rays), radio waves, alpha rays, beta rays, electron rays, plasmas, ionizing rays, and particle rays. Preferably, it is ultraviolet light. Although not shown in figure, a separator may be provided in the outer side of an adhesive layer for the purpose of protecting an adhesive layer until it uses a masking material for use. In addition, the masking material may include any other suitable layer (not shown). For example, any appropriate layer may be formed between the base material and the pressure-sensitive adhesive layer.

In one embodiment, the masking material may be used when an electronic component having a convex portion formed thereon (hereinafter also referred to as a concave-convex surface or a surface to be masked) is provided to a dicing process with the masked surface. In the said process, the electronic component in the state in which the uneven|corrugated surface was masked with the said masking material is cut and separated into element pieces. In one embodiment, the said masking material adheres an adhesive layer to the uneven|corrugated surface of an electronic component, and is used. In addition, at the time of a dicing process, any suitable dicing tape may be arrange|positioned on the unmasked side of the electronic component with a masking material. Further, when using the masking material, it is preferable to adhere the masking material to the masked surface of the adherend, then irradiate the active energy ray to cure the pressure-sensitive adhesive layer, and then dic the masked electronic component. Hardening of an adhesive layer is ^{performed by irradiating the ultraviolet-ray of 500 mJ/cm<2>} (light source: high-pressure mercury-vapor lamp) of accumulated light quantity, for example. At the time of the cutting and separation, for example, a rotary blade is used. In one embodiment, after the dicing process, the fragmented electronic component is masked with the masking material of the present invention in the next process (for example, a metal film forming process such as sputtering, etching process, etc.) is provided on

The masking material is adhered to the silicon wafer, irradiated with active energy rays, and the surface roughness (arithmetic mean height) Sa of the dicing cut surface of the pressure-sensitive adhesive layer after dicing the masking material and the silicon wafer in a cured state 3 μm or less. When the surface roughness Sa of the dicing cut surface is 3 µm or less, contamination of the adherend with chips can be prevented. The surface roughness Sa of the dicing cut surface of the masking material is preferably 2 µm or less, more preferably 1.5 µm or less, still more preferably 1 µm or less, and particularly preferably 0.75 µm or less. The surface roughness Sa of the dicing cut surface is preferably so small that it is, for example, 0.05 µm or more. In this specification, the surface roughness Sa of the dicing cut surface of a masking material means the value measured by the method described in the Example mentioned later.

The thickness of the masking material of this invention becomes like this. Preferably they are 60 micrometers - 800 micrometers, More preferably, they are 110 micrometers - 600 micrometers, More preferably, they are 150 micrometers - 450 micrometers. When the thickness of the masking material is thinner than 60 µm, the unevenness cannot be filled in and there is a fear that the adherend cannot be protected. Moreover, when it is thicker than 800 micrometers, there exists a possibility that the handling property as a masking material may worsen.

In one embodiment, the thickness of a masking material is more than the height (for example, 50 micrometers - 250 micrometers) of the convex part which the said electronic component has. If the masking material comprised in this way is used, the electronic component which has an uneven surface can be masked favorably. Ratio of the thickness of a masking material and the height of the convex part which an electronic component has (thickness of a masking material/height of a convex part) becomes like this. Preferably it is 1-5, More preferably, it is 1.5-4.

B. Adhesive layer

In one embodiment, the pressure-sensitive adhesive layer is formed from an active energy ray-curable pressure-sensitive adhesive. The active energy ray-curable pressure-sensitive adhesive contains, typically, a base polymer and any appropriate photopolymerization initiator. By using an active energy ray-curable adhesive, it is low elasticity and high flexibility at the time of sticking, and it is excellent in handling property, and can fill the unevenness|corrugation by the bump of a semiconductor package favorably. On the other hand, in the scene requiring peeling, the masking material which can reduce adhesive force can be obtained by irradiating an active energy ray. Examples of active energy rays include gamma rays, ultraviolet rays, visible rays, infrared rays (hot rays), radio waves, alpha rays, beta rays, electron rays, plasmas, ionizing rays, and particle rays. Preferably, it is ultraviolet light.

The storage elastic modulus after active energy ray irradiation of an adhesive layer becomes like this. Preferably they are 30 Mpa - 300 Mpa, More preferably, they are 40 Mpa - 280 Mpa, More preferably, they are 50 Mpa - 250 Mpa. When the storage elastic modulus after active energy ray irradiation is the said range, the contamination of the to-be-adhered body in a cutting process can be prevented favorably. Moreover, the masking material can be easily peeled from a to-be-adhered body after active energy ray irradiation. The storage elastic modulus after active energy ray irradiation of an adhesive layer can be measured using a solid-state viscoelasticity measuring apparatus. In the present specification, the storage elastic modulus at 22° C. measured at a frequency of 1 Hz and a temperature increase rate of 10° C./min using a solid viscoelasticity measuring device (Rheometric Scientific Co., Ltd., trade name “RSAIII”) is measured as an adhesive. Let it be the storage modulus of the layer. In addition, irradiation conditions of an active energy ray (ultraviolet ray) are as follows.

<Ultraviolet irradiation conditions>

Ultraviolet irradiator: Nitto Seiki Co., Ltd., brand name: UM810

Light source: high pressure mercury lamp

Irradiation intensity: 50 mW/cm ² (Measuring device: “Ultraviolet illuminometer UT-101” manufactured by Ushio Corporation)

Irradiation Time: 10 seconds

Integrated light intensity: 500 mJ/cm ²

The breaking strength after active energy ray irradiation of an adhesive layer becomes like this. Preferably they are 7 MPa - 15 MPa, More preferably, they are 8 MPa - 13 MPa. When the breaking strength after active energy ray irradiation is the said range, the glue residue with respect to the to-be-adhered body at the time of peeling of a masking material can be prevented. The breaking strength after active energy ray irradiation can be measured using a tensile tester. In the present specification, using a tensile tester (manufactured by ORIENTEC, trade name "RTG-1210"), the SS curve is measured under the conditions of a measurement temperature of 22°C, a distance between chucks of 10 mm, and a speed of 10 mm/min, and the breaking point of the SS curve Breaking strength (MPa) is computed from the test force in , and let this value be the breaking strength of the adhesive layer after active energy ray irradiation. In addition, irradiation conditions of an active energy ray (ultraviolet ray) are as follows.

<Ultraviolet irradiation conditions>

Ultraviolet irradiator: Nitto Seiki Co., Ltd., brand name: UM810

Light source: high pressure mercury lamp

Irradiation intensity: 50 mW/cm ² (Measuring device: “Ultraviolet illuminometer UT-101” manufactured by Ushio Corporation)

Irradiation Time: 10 seconds

Integrated light intensity: 500 mJ/cm ²

The thickness of an adhesive layer becomes like this. Preferably they are 10 micrometers - 500 micrometers, More preferably, they are 30 micrometers - 300 micrometers, More preferably, they are 50 micrometers - 250 micrometers. When the thickness of the pressure-sensitive adhesive layer is thinner than 10 µm, the unevenness cannot be filled and there is a fear that the adherend cannot be protected. Moreover, when it is thicker than 500 micrometers, there exists a possibility that the handling property as a masking material may worsen.

In one embodiment, the thickness of the said adhesive layer is more than the height (for example, 50 micrometers - 250 micrometers) of the convex part which the said electronic component has. If the masking material comprised in this way is used, the electronic component which has an uneven surface can be masked favorably. Ratio (thickness of an adhesive layer/height of a convex part) of the thickness of an adhesive layer and the height of the convex part which an electronic component has becomes like this. Preferably it is 1-3, More preferably, it is 1.2-2.

B-1. base polymer

The base polymer is obtained by polymerizing any suitable monomer composition. As the monomer component contained in the monomer composition, any appropriate monomer is used. Preferably, a monomer composition containing a (meth)acrylic monomer is used. In one embodiment, the base polymer of the active energy ray-curable pressure-sensitive adhesive is a (meth)acrylic monomer having at least one alkyl group selected from the group consisting of a methyl group and an ethyl group (hereinafter referred to as a (meth)acrylic monomer having a methyl group and/or an ethyl group (meth) ) It is a polymer obtained by superposing|polymerizing the monomer composition containing 5 mol% - 20 mol% of acrylic monomer). By using the polymer obtained by polymerizing the monomer composition, it is possible to prevent contamination (eg, glue residue) on the adherend. When the content rate of the (meth)acrylic-type monomer which has a methyl group and/or an ethyl group in a monomer composition is less than 5 mol%, there exists a possibility that generation|occurrence|production of the waste at the time of dicing may become easy to produce. When the content rate of the (meth)acrylic-type monomer which has a methyl group and/or an ethyl group in a monomer composition exceeds 20 mol%, there exists a possibility that peeling of a masking material may become difficult. The content rate of the (meth)acrylic-type monomer which has a methyl group and/or an ethyl group in a monomer composition becomes like this. Preferably it is 8 mol% - 17 mol%, More preferably, it is 8 mol% - 15 mol%. In addition, in this specification, "(meth)acryl" means acryl and/or methacryl.

As a (meth)acrylic-type monomer which has a methyl group and/or an ethyl group, arbitrary suitable (meth)acrylic-type monomers can be used. The (meth)acrylic-type monomer which has a methyl group and/or an ethyl group may have one methyl group or an ethyl group, and may have it two or more. When it has two or more methyl groups and/or an ethyl group, you may have either a methyl group or an ethyl group, and may have a methyl group and an ethyl group. Specific examples of the (meth)acrylic monomer having a methyl group and/or an ethyl group include methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate. Preferably, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate are used. Only 1 type may be used for the (meth)acrylic-type monomer which has a methyl group and/or an ethyl group, and may be used in combination of 2 or more type.

Any suitable monomer can be used as the (meth)acrylic monomer (hereinafter also referred to as another (meth)acrylic monomer) other than the (meth)acrylic monomer having a methyl group and/or an ethyl group. Typically, an alkyl (meth)acrylate can be used. Specifically, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, pentyl (meth) acrylic rate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (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, octadecyl (meth) acrylate, nonadecyl (meth) and (meth)acrylic acid C3-C20 alkyl esters such as acrylate and eicosyl (meth)acrylate. As a (meth)acrylic-type monomer, only 1 type may be used and may be used in combination of 2 or more type.

The content rate of the other (meth)acrylic-type monomer in a monomer composition can be made into arbitrary appropriate quantities. Specifically, the other (meth)acrylic monomer is used so that the sum of the above-mentioned (meth)acrylic monomer having a methyl group and/or an ethyl group, an optional hydroxyl group-containing monomer, and an optional copolymerizable monomer component is 100 mol%. .

In addition, for the purpose of modifying cohesive force, heat resistance, crosslinkability, etc., if necessary, other monomer components copolymerizable with the (meth)acrylic acid alkyl ester may be further used. As such a monomer component, For example, carboxyl group containing monomers, such as acrylic acid and methacrylic acid; acid anhydride monomers such as maleic anhydride and icotanic anhydride; Hydroxyl group-containing monomers, such as (meth)acrylic-acid hydroxyethyl and (meth)acrylic-acid hydroxypropyl; sulfonic acid group-containing monomers such as styrenesulfonic acid and allylsulfonic acid; (N-substituted) amide-based monomers such as (meth)acrylamide and N,N-dimethyl (meth)acrylamide; (meth)acrylic acid aminoalkyl-based monomers such as (meth)acrylic acid aminoethyl; (meth)acrylic acid alkoxyalkyl monomers such as methoxyethyl (meth)acrylate; maleimide-based monomers such as N-cyclohexyl maleimide and N-isopropyl maleimide; itaconimide-based monomers such as N-methyl itaconimide and N-ethyl itaconimide; succinimide-based monomers; vinyl-based monomers such as vinyl acetate, vinyl propionate, N-vinyl pyrrolidone, and methyl vinyl pyrrolidone; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; Epoxy group-containing acrylic monomers, such as (meth)acrylic-acid glycidyl; glycol-based acrylic ester monomers such as (meth)acrylic acid polyethylene glycol and (meth)acrylic acid polypropylene glycol; an acrylic acid ester-based monomer having a heterocyclic ring such as (meth)acrylic acid tetrahydrofurfuryl, fluorine (meth)acrylate, or silicone (meth)acrylate, a halogen atom, or a silicon atom; olefinic monomers such as isoprene, butadiene, and isobutylene; Vinyl ether type monomers, such as vinyl ether, etc. are mentioned. Only 1 type may be used for these monomer components, and may be used in combination of 2 or more type.

In one embodiment, the monomer composition preferably further comprises a hydroxyl group-containing monomer. The content ratio of the hydroxyl group-containing monomer in the monomer composition is preferably 10 mol% to 30 mol%, and more preferably 15 mol% to 25 mol%. By using a monomer composition containing a hydroxyl group-containing monomer, a base polymer having a hydroxyl group is obtained, and this hydroxyl group can serve as an introduction point for any suitable substituent. For example, a base polymer having a carbon-carbon double bond is obtained by reacting a polymer (prepolymer) obtained by reacting the monomer composition with a compound having a polymerizable carbon-carbon double bond. By using a base polymer having a carbon-carbon double bond, a masking material that can be cut in a flatter state can be obtained.

Any suitable monomer can be used as a hydroxyl-containing monomer. For example, acrylic acid, methacrylic acid, 2-hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxymethyl methacrylate, 2-hydroxyethyl methacrylate, N-(2-hydroxyethyl) acrylamide, and the like. Preferably, acrylic acid, methacrylic acid, 2-hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxymethyl methacrylate, 2-hydroxyethyl methacrylate are used. Only 1 type may be used for these monomers, and may be used in combination of 2 or more type.

In one embodiment, the base polymer is a polymer having a carbon-carbon double bond. By using an active energy ray-curable pressure-sensitive adhesive containing a base polymer having a carbon-carbon double bond, a masking material that can be cut in a flatter state can be obtained. The base polymer having a carbon-carbon double bond can be obtained, for example, by reacting a prepolymer obtained by polymerizing the monomer composition with a compound having a polymerizable carbon-carbon double bond.

The compound having a carbon-carbon double bond preferably has an isocyanate group. By having an isocyanate group, it reacts with the hydroxyl group which the said prepolymer has, and a carbon-carbon double bond can be introduce|transduced into a base polymer.

As the compound having a polymerizable carbon-carbon double bond, any suitable compound can be used. For example, methacryloisocyanate, 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), m-isopropenyl-α,α-dimethylbenzyl Isocyanate etc. are mentioned.

The compound having a polymerizable carbon-carbon double bond is used in any suitable amount. For example, content can be adjusted according to the content rate of the said hydroxyl-containing monomer in a monomer composition. In one embodiment, the compound which has a polymerizable carbon-carbon double bond is preferably used so that it may become 40 mol% - 95% of moles of the hydroxyl group of a hydroxyl-containing monomer. When the compound having a polymerizable carbon-carbon double bond is less than 40 mol% of the number of moles of hydroxyl groups in the hydroxyl group-containing monomer, there is a possibility that the compound may not be sufficiently cured upon irradiation with active energy rays. When the compound having a polymerizable carbon-carbon double bond exceeds 95 mol% of the number of moles of hydroxyl groups in the hydroxyl group-containing monomer, the reaction points with the crosslinking agent decrease, and there is a fear that a sufficient crosslinking effect may not be obtained.

The base polymer may be obtained by any suitable method. For example, a monomer composition comprising a (meth)acrylic monomer having a methyl group and/or an ethyl group, another (meth)acrylic monomer, and an optional hydroxyl group-containing monomer may be obtained by polymerizing by any suitable polymerization method. can When the base polymer has a carbon-carbon double bond, for example, a (meth)acrylic monomer having a methyl group and/or an ethyl group, a monomer composition comprising the (meth)acrylic monomer, and an optional hydroxyl group-containing monomer, optionally After obtaining a prepolymer by polymerization by an appropriate polymerization method, the base polymer is obtained by reacting the prepolymer with a compound having a polymerizable carbon-carbon double bond.

B-2. additive

The said active-energy-ray-curable adhesive can contain arbitrary appropriate additives as needed. Examples of the additive include a photopolymerization initiator, a crosslinking agent, a catalyst (eg, a platinum catalyst), a tackifier, a plasticizer, a pigment, a dye, a filler, an antioxidant, a conductive material, an ultraviolet absorber, a light stabilizer, a peeling regulator, A softener, surfactant, a flame retardant, a solvent, etc. are mentioned.

In one embodiment, the active energy ray-curable pressure-sensitive adhesive preferably contains a photopolymerization initiator. As a photoinitiator, arbitrary appropriate initiators can be used.

The photopolymerization initiator may be used in any suitable amount. To [ content of a photoinitiator / 100 weight part of said ultraviolet curing adhesives ], Preferably they are 0.1 weight part - 10 weight part, More preferably, they are 0.5 weight part - 7 weight part. When content of a photoinitiator is less than 0.1 weight part, there exists a possibility that it may not fully harden|cure at the time of active energy ray irradiation. When content of a photoinitiator exceeds 10 weight part, there exists a possibility that the storage stability of an adhesive may fall.

In one embodiment, the said active energy ray hardening-type adhesive further contains a crosslinking agent. As a crosslinking agent, an isocyanate type crosslinking agent, an epoxy type crosslinking agent, an aziridine type crosslinking agent, a chelate type crosslinking agent, etc. are mentioned, for example. To [ content of a crosslinking agent / 100 weight part of base polymers contained in an active energy ray-curable adhesive ], Preferably it is 0.01 weight part - 10 weight part, More preferably, they are 0.02 weight part - 5 weight part, More preferably 0.025 parts by weight to 0.5 parts by weight. The softness|flexibility of an adhesive layer is controllable by the content rate of a crosslinking agent. When content of a crosslinking agent is less than 0.01 weight part, an adhesive becomes a sol phase, and there exists a possibility that an adhesive layer cannot be formed. When content of a crosslinking agent exceeds 10 weight part, the adhesiveness to a to-be-adhered body may fall, and there exists a possibility that a to-be-adhered body cannot be fully protected.

In one embodiment, an isocyanate type crosslinking agent is used preferably. The isocyanate-based crosslinking agent is preferable in that it can react with a variety of functional groups. Particularly preferably, a crosslinking agent having three or more isocyanate groups is used. By using an isocyanate type crosslinking agent as a crosslinking agent and making content of a crosslinking agent into the said range, even after heating, it is excellent in peelability and can form the adhesive layer with remarkably little glue residue.

In one embodiment, the active energy ray hardening-type adhesive, Preferably a radical scavenger is further included. In this specification, a radical scavenger means a compound which can react with a radical under heating (for example, 100 degreeC - 200 degreeC). As such a radical scavenger, azo compounds, such as peroxides, such as a benzoyl peroxide, and azobisisobutyronitrile, etc. are mentioned, for example. By using a radical scavenger, the residual ratio of the double bond in a base polymer (for example, acryl-type polymer) can be raised.

To [ content of a radical scavenger / 100 weight part of base polymers of an adhesive ], Preferably it is 1 weight part or less, More preferably, they are 0.04 weight part - 0.08 weight part. If it is such a range, the effect of increasing the said residual ratio of a carbon-carbon double bond becomes remarkable. When content of a radical scavenger exceeds 1 weight part, the radical from a photoinitiator is also acquired and there exists a possibility that an adhesive may not fully be hardened by active energy ray irradiation.

C. Subscription

The substrate may be composed of any suitable resin. Examples of the resin include polyolefins such as low-density polyethylene, linear polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymerized polypropylene, block copolymerized polypropylene, homopolypropylene, polybutene, and polymethylpentene. , ethylene-vinyl acetate copolymer, ionomer resin, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, poly oil polyester such as lethane and polyethylene naphthalate, polyimide, polyether ketone, polystyrene, polyvinyl chloride, polyvinylidene chloride, fluororesin, silicone resin, cellulose resin, and crosslinked products thereof. there is.

The thickness of the substrate is preferably 5 µm to 125 µm, more preferably 10 µm to 75 µm, and still more preferably 12 µm to 50 µm. In such a range, it is possible to obtain a masking material that has appropriate rigidity, facilitates the pasting operation, and is excellent in handling properties. When the thickness of the substrate is less than 5 μm, it may not function sufficiently as a support, and handling of the masking material may become difficult. When the thickness of the base material exceeds 125 µm, the whiskers are remarkably generated from the base material during dicing, and there is a risk of contaminating the adherend.

The surface of the said base material may be arbitrary surface-treated in order to improve adhesiveness with an adjacent layer, holdability, etc. Examples of the surface treatment include chemical or physical treatment such as chromic acid treatment, ozone exposure, flame exposure, high-pressure electric shock exposure, and ionizing radiation treatment, and coating treatment.

D. Manufacturing method of masking material

The masking material may be prepared by any suitable method. For example, after apply|coating an adhesive solution (active energy ray hardening-type adhesive) to a separator, drying and forming an adhesive layer on a separator, it can obtain by the method of bonding it to a base material. Moreover, on a base material, the said adhesive solution may be apply|coated, and it may dry and obtain a masking material. As a method of applying the pressure-sensitive adhesive solution, various methods such as bar coater application, air knife application, gravure application, gravure reverse application, reverse roll application, lip application, die application, dip application, offset printing, flexographic printing, screen printing, etc. can be hired As the drying method, any suitable method may be employed. In one embodiment, the said pressure-sensitive adhesive layer may be formed through any appropriate curing treatment.

E. Use of masking material

The masking material can be suitably used in a semiconductor manufacturing process. In one embodiment, the masking material may be used when providing an electronic component masked by the masking material to a dicing process. In the said process, the electronic component in the state masked by the masking material is cut and separated into element small pieces. In one embodiment, the said masking material is used by sticking an adhesive layer to the uneven|corrugated surface of an electronic component. In addition, at the time of a dicing process, any suitable dicing tape may be arrange|positioned on the unmasked side of the electronic component with a masking material. Further, when using the masking material, it is preferable to adhere the masking material to the masking surface of the adherend, then irradiate the active energy ray to cure the pressure-sensitive adhesive layer, and then dic the masked electronic component. In the case of the said cutting|disconnection, a rotating blade is used, for example. In one embodiment, after the dicing process, the fragmented electronic component is masked with the masking material of the present invention in the next process (for example, a metal film forming process such as sputtering, etching process, etc.) is provided

Example

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. In addition, in the Example, unless otherwise specified, "part" and "%" are based on weight.

[Example 1]

The monomer components described in Table 1, the solvent (methyl ethyl ketone), and azobisisobutyronitrile were mixed to obtain a monomer composition. The obtained monomer composition was put into a 1L round-bottom separable flask, a separable cover, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig cooler, a vacuum seal, a stirring rod, and a stirring blade equipped with a polymerization experiment apparatus equipped with, While stirring, nitrogen substitution was carried out at room temperature for 6 hours. Thereafter, while nitrogen was introduced and stirred, the polymerization was carried out by holding at 65°C for 4 hours and then at 75°C for 2 hours to obtain a resin solution (prepolymer).

Next, the obtained resin solution was cooled to room temperature. Thereafter, 77.19 parts by weight of 2-isocyanatoethyl methacrylate (manufactured by Showa Denko Corporation, trade name “Carenz MOI”) was added to the resin solution as a compound having a polymerizable carbon-carbon double bond. Furthermore, 0.39 weight part of dibutyltin dilaurate IV (made by Wako Pure Chemical Industries, Ltd.) was added, it stirred at 50 degreeC in air atmosphere for 24 hours, and obtained the base polymer.

With respect to 100 parts by weight of the solid content of the obtained base polymer, 0.1 parts by weight of a polyisocyanate crosslinking agent (manufactured by Nippon Polyurethane Kogyo Co., Ltd., trade name "Coronate L"), and a photopolymerization initiator (manufactured by IGM Resins BV, trade name "Omnirad 369E") 0.5 parts by weight was mixed and adjusted. Using toluene as a dilution solvent, it adjusted so that it might become 45% of solid content, and the adhesive solution was obtained.

A pressure-sensitive adhesive solution was applied to the release-treated surface of a polyethylene terephthalate (PET) separator (manufactured by Mitsubishi Chemical, trade name “Diafoil MRF38”), and dried at 120° C. for 3 minutes using a dryer to form an adhesive layer with a thickness of 200 μm. . Next, the surface of the pressure-sensitive adhesive layer, which is not in contact with the PET separator, is bonded to the corona-treated surface of the corona-treated base film (manufactured by Toray Corporation, trade name "Lumiror (registered trademark) #38-S105") so as not to contain air bubbles. , light-shielding It was left to stand under room temperature for 168 hours, and the adhesive tape (masking material) was obtained.

[Example 2]

Adhesive tape (masking material) in the same manner as in Example 1, except that the composition of the monomer composition was changed as described in Table 1, and the amount of 2-isocyanatoethyl methacrylate added was 78.25 parts by weight to prepare an adhesive solution. got

[Example 3]

Adhesive tape (masking material) in the same manner as in Example 1 except that the composition of the monomer composition was changed as described in Table 1, and the addition amount of 2-isocyanatoethyl methacrylate was 77.20 parts by weight to prepare an adhesive solution. got

[Example 4]

The composition of the monomer composition was changed as described in Table 1, and the amount of 2-isocyanatoethyl methacrylate added was 56.00 parts by weight, and the amount of azobisisobutyronitrile was 0.28 parts by weight, and the pressure-sensitive adhesive solution was prepared. Except it, it carried out similarly to Example 1, and obtained the adhesive tape (masking material).

[Example 5]

The composition of the monomer composition was changed as shown in Table 1, and the amount of 2-isocyanatoethyl methacrylate added was 29.25 parts by weight, and the amount of azobisisobutyronitrile was 0.15 parts by weight, and the pressure-sensitive adhesive solution was prepared. Except it, it carried out similarly to Example 1, and obtained the adhesive tape (masking material).

(Comparative Example 1)

The composition of the monomer composition was changed as described in Table 1, and the amount of 2-isocyanatoethyl methacrylate added was 25.86 parts by weight, and the amount of azobisisobutyronitrile was 0.13 parts by weight, and an adhesive solution was prepared. Except it, it carried out similarly to Example 1, and obtained the adhesive tape (masking material).

(Comparative Example 2)

The composition of the monomer composition was changed as described in Table 1, and the amount of 2-isocyanatoethyl methacrylate added was 71.41 parts by weight, and the amount of azobisisobutyronitrile was 0.36 parts by weight, and the pressure-sensitive adhesive solution was prepared. Except it, it carried out similarly to Example 1, and obtained the adhesive tape (masking material).

(Comparative Example 3)

The composition of the monomer composition was changed as described in Table 1, and the amount of 2-isocyanatoethyl methacrylate added was 84.44 parts by weight, and the amount of azobisisobutyronitrile was 0.42 parts by weight, and the pressure-sensitive adhesive solution was prepared. Except it, it carried out similarly to Example 1, and obtained the adhesive tape (masking material).

<Evaluation>

The following evaluation was performed using the masking material obtained by the Example and the comparative example, or the adhesive solution used by each Example and the comparative example. A result is shown in Table 1.

1. Evaluation of the pressure-sensitive adhesive layer

The adhesive solution used in Examples 1 to 5 and Comparative Examples 1 to 3 was applied to the release-treated surface of a PET separator (manufactured by Mitsubishi Chemical, trade name "Diafoil MRA38"), and dried at 120° C. for 3 minutes using a dryer, A pressure-sensitive adhesive layer having a thickness of 200 μm was formed. Next, the surface of the adhesive layer not in contact with the PET separator was bonded to another PET separator (manufactured by Mitsubishi Chemical, trade name "Diafoil MRA38"), and left to stand at light-shielding room temperature for 168 hours. Then, the ultraviolet-ray was irradiated to the adhesive layer on the following ultraviolet irradiation conditions. The adhesive layer after ultraviolet irradiation was cut to the size of 10 mm x 30 mm, and this was made into the evaluation sample. Breaking strength and storage modulus E' were measured using this evaluation sample.

<Ultraviolet irradiation conditions>

Ultraviolet irradiator: Nitto Seiki Co., Ltd., brand name: UM810

Light source: high pressure mercury lamp

Irradiation intensity: 50 mW/cm ² (Measuring device: “Ultraviolet illuminometer UT-101” manufactured by Ushio Corporation)

Irradiation Time: 10 seconds

Integrated light intensity: 500 mJ/cm ²

(1) Breaking strength

Using a tensile tester (manufactured by ORIENTEC, trade name "RTG-1210"), the SS curve was measured under the conditions of a measurement temperature of 22°C, a distance between chucks of 10 mm, and a speed of 10 mm/min, and the breaking strength ( MPa) was computed, and this was made into the breaking strength of the adhesive layer after ultraviolet irradiation. The measurement was performed 5 times, and the average value was made into the measured value.

(2) storage modulus E'

The evaluation sample was cut into strips with a thickness of 200 μm, a length of 25 mm (measured length), and a width of 10 mm with a cutter knife, and using a solid viscoelasticity measuring device (Rheometric Scientific Co., Ltd., trade name “RSAIII”) , the storage modulus E' in -50°C to 300°C was measured. The measurement conditions were a frequency of 1 Hz and a temperature increase rate of 10°C/min, and the storage elastic modulus E' in 22°C was defined as the storage elastic modulus E' of each sample.

2. Evaluation of masking material

The masking materials obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were subjected to a temperature of 22°C and a humidity of 50% in an environment of a Si-bare wafer (method; CZ, conductivity type; P, impurity; B, thickness; 750 µm, resistivity; Hand roller on the surface of 1Ωcm∼50Ωcm, surface; mirror, back surface; mirror, crystal orientation (100), surface impurities Fe, Ni, Cu, Zn, Cr, Al, Na<1.0 (×10 ¹⁰ atoms/cm ² )) was applied without causing air bubbles to bite. On the other hand, it affixed in the form which covered the whole Si wafer with a masking material.

Next, ultraviolet ray was irradiated from the base material side of the masking material under the said ultraviolet irradiation conditions, and the adhesive layer of the masking material was hardened. Then, the brand name "NBD-7163K" (made by Nitto Denko Corporation) was affixed as a dicing tape on the wafer back surface side. A dicing ring for dicing was affixed to the pressure-sensitive adhesive surface of the dicing tape. After sticking, it was left to stand at light-shielding 22 degreeC for 30 minutes. Thereafter, blade dicing of the masking material, the Si bare wafer, and the dicing tape was performed under the following conditions.

<Dicing conditions>

Dicing device: Disco Corporation, product name "DFD-6450"

Cut method: single cut

Dicing speed: 55mm/sec

Dicing blade: manufactured by Disco, trade name "P1A861 SDC400N75BR597" (the following dress diced)

Dicing blade rotation speed: 35,000rpm

Blade height: 75μm

Quantity: 1.5L/min

Wafer chip size: 5.0mm each

On the other hand, as the blade used for dicing, a blade subjected to dress dicing under the following conditions was used.

A dicing ring and a board (made by Disco, trade name: DRESSER BOARD BGCA0172) were affixed to the adhesive layer of a dicing tape (The Nitto Denko company make, brand name "NBD-7163K"), and the work for a process was produced. Next, the obtained workpiece|work was diced under the following conditions, and the blade for the said dicing process was obtained.

<Dress Dicing Conditions>

Dicing device: Disco Corporation, product name "DFD-6450"

Cut method: single cut

Dicing speed: 55mm/sec

Dicing blade: Brand new "P1A861 SDC400N75BR597" made by Disco Corporation

Dicing blade rotation speed: 35,000rpm

Blade height: 500μm

Quantity: 1.5L/min

Distance of one dicing: overall length of the board

Dicing Thickness: 1mm Thickness

Number of dicing: 100 times

After dicing, ultraviolet rays were irradiated from the base material side of the dicing tape toward the Si-bare wafer under the following conditions.

<Ultraviolet irradiation conditions>

Ultraviolet irradiator: Nitto Seiki Co., Ltd., brand name: UM810

Light source: high pressure mercury lamp

Irradiation intensity: 50 mW/cm ² (Measuring device: Ushio Corporation, product name “Ultraviolet illuminometer UT-101”)

Irradiation Time: 6 seconds

Accumulated light intensity: 300mJ/cm ²

Thereafter, the masking material and the Si-bare wafer fragmented into 5 mm x 5 mm were recovered from the dicing tape using tweezers. On the other hand, when using tweezers, care was taken so that the tweezers did not touch the dicing cut surface.

The following evaluation was performed using the fragmented masking material and Si bare wafer.

(3) Surface roughness Sa of the pressure-sensitive adhesive layer

A double-sided tape (manufactured by Nitto Denko Corporation, trade name "No. 5000NS") was affixed to the surface of the unground Si mirror wafer. Next, on the surface of the double-sided tape not in contact with the Si mirror wafer, a layered product of the fragmented masking material and the Si bare wafer was affixed with tweezers. On the other hand, pasting was performed so that a dicing cut surface and a double-sided tape might be bonded together, and the place (most surface) farthest from the double-sided tape was performed so that it might become the dicing cut surface finally diced.

Finally, about the dicing cut surface diced, observation and measurement were performed using the laser microscope (The Kiens Corporation make, product name "VK-X150"). As the PC software, "Observation application VK-H1XV2 version 2.5.0.0" manufactured by Giens Corporation was used. As the objective lens, "20X/0.46 OFN25 WD 3.1" (manufactured by Nikon) was used. By "shape measurement" of PC software, the roughness measurement of the dicing cut surface of the masking material adhesive layer was performed. Measurement settings were performed under the following conditions.

<Measurement Settings>

Measurement mode: transparent body (most surface)

Measurement size: standard (1024X768)

Measurement quality: high precision

Pitch: 0.75μm

Next, the three-dimensional data obtained by the measurement was saved. On the other hand, it was set as the state in which the adhesive layer cross section is reflected in all from the left edge to the right edge of a screen. A cross-section of the pressure-sensitive adhesive layer with a thickness of 200 μm entered the screen. After that, "tilt correction" in "image processing" of the PC software was performed. As a correction|amendment method, in the state which matched the center of two lines with the center of the adhesive layer of the observation image obtained by selecting surface inclination correction (profile), inclination correction was implemented so that a cut surface might become horizontal. After the inclination correction, the three-dimensional data after correction was saved. Next, three-dimensional data was analyzed using PC software for analysis "multi-file analysis application VK-H1XM version 1.1.22.87" (manufactured by Kiens Corporation). "Surface roughness" of PC software for analysis was selected, the whole adhesive layer cross section reflected as an image was selected, and surface roughness Sa (micrometer) was measured.

(4) Residual debris on the object to be masked

A double-sided tape (manufactured by Nitto Denko Corporation, trade name "No. 5000NS") was affixed to the surface of the unground Si mirror wafer. Next, on the surface of the double-sided tape not in contact with the Si mirror wafer, a layered product of the fragmented masking material and the Si bare wafer was affixed with tweezers. On the other hand, pasting was performed so that a dicing cut surface and a double-sided tape might be bonded together, and the place (most surface) farthest from the double-sided tape was performed so that it might become the dicing cut surface finally diced.

Finally, about the dicing cut surface diced, observation and measurement were performed using the laser microscope (The Kiens Corporation make, product name "VK-X150"). As the PC software, "Observation application VK-H1XV2 version 2.5.0.0" manufactured by Giens Corporation was used. As the objective lens, "20X/0.46 OFN25 WD 3.1" (manufactured by Nikon) was used. What "absence" and the thing to which the debris had adhered to the body to be masked (Si bare wafer) to which the debris derived from an adhesive layer did not adhere was evaluated as "presence".

(5) Peelability from the object to be masked and residual glue to the object to be masked

Using the fragmented masking material and Si bare wafer, peeling of the masking material from the Si bare wafer was attempted with tweezers. The thing which could peel easily was evaluated as "easy", and the thing which could not peel easily was evaluated as "impossible".

Moreover, the masking material affixing surface of the Si bare wafer after peeling was observed with the microscope, and the presence or absence of a glue residue was confirmed. What "absence" and the thing in which the grass residue was seen was made into "presence" what was not seen by the microscope with the paste|pool residue.

The masking material of the present invention can be suitably used for masking of electronic components used in a dicing process.

10 entries
20 Adhesive layer
100 masking material

Claims (6)

A pressure-sensitive adhesive layer formed of an active energy ray-curable pressure-sensitive adhesive, and a substrate,
Obtained by polymerizing a monomer composition in which the base polymer of the active energy ray-curable pressure-sensitive adhesive contains 5 mol% to 20 mol% of a (meth)acrylic monomer having at least one alkyl group selected from the group consisting of a methyl group and an ethyl group. As a polymer masking material,
The masking material is affixed to a silicon wafer, irradiated with active energy rays, and the surface roughness Sa of the dicing cut surface of the pressure-sensitive adhesive layer after dicing the masking material and the silicon wafer in a cured state of the pressure-sensitive adhesive layer is 3 µm or less, the masking material . The method of claim 1,
The monomer composition further comprises a hydroxyl group-containing monomer,
The masking material whose content rate in the monomer composition of this hydroxyl-containing monomer is 10 mol% - 30 mol%. The method of claim 1,
The said base polymer is a polymer which has a carbon-carbon double bond, The masking material. The method of claim 1,
The storage elastic modulus in 22 degreeC after active energy ray irradiation of the said adhesive layer is 30 Mpa - 300 Mpa, The masking material. The method of claim 1,
The masking material whose breaking strength in 22 degreeC after active energy ray irradiation of the said adhesive layer is 7 MPa - 15 MPa. The method of claim 1,
A masking material used in a semiconductor manufacturing process.

Images