JP6541775B2 - Adhesive tape for work processing - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive tape for processing a work, and more particularly to a pressure-sensitive adhesive tape for protecting the surface of a semiconductor wafer which is used to protect the surface of a semiconductor wafer with bumps.

  With the rapid progress in thinning, downsizing and multifunctionalization of information terminal equipment, thinning and densification of semiconductor devices mounted on them are also required, and thinning of semiconductor wafers is also demanded. ing. Conventionally, in order to meet the demand, the back surface of a semiconductor wafer is ground and thinned. Also, in recent years, in semiconductor wafers, bumps made of solder or the like having a height of about 30 to 100 μm may be formed on the wafer surface. When such a bumped semiconductor wafer is back-ground, a surface protective sheet may be attached to the wafer surface on which the bumps are formed, in order to protect the bump portion.

  Conventionally, as a surface protection sheet, a sheet including a resin layer in which the storage elastic modulus at 25 ° C. and 60 ° C. is adjusted to a specific range is known (see, for example, Patent Document 1). This surface protective sheet is attached to a wafer surface having an uneven portion at a high temperature by providing a resin layer having a difference between the storage elastic modulus at room temperature (25 ° C.) and the storage elastic modulus at high temperature (60 ° C.) Then, the resin layer is softened to absorb unevenness on the wafer surface, thereby reducing the difference in height on the wafer surface.

  Moreover, as a surface protection sheet, in order to make adhesiveness and releasability favorable, two resin layers which have a predetermined | prescribed elastic modulus in tension are provided on a base material, and affixing surface is carried out among these two resin layers. It is known that the resin layer on the side is formed of a thermoplastic elastomer such as a polystyrene elastomer, a polyolefin elastomer, a polyurethane elastomer, and a polyester elastomer (see Patent Document 2).

  Furthermore, a pressure-sensitive adhesive tape in which an intermediate layer and a pressure-sensitive adhesive layer are provided on one surface of a substrate is also known as a surface protective sheet. In this pressure-sensitive adhesive tape, it is known that the storage elastic modulus at 25 ° C. of the intermediate layer is set to about 30 to 1000 kPa and the pressure-sensitive adhesive layer is formed of an energy ray-curable pressure-sensitive adhesive in order to enhance unevenness absorbability. (See, for example, Patent Document 3). As in Patent Document 3, when an energy ray-curable pressure-sensitive adhesive is used for the surface protective sheet, the adhesion to a semiconductor wafer and the releasability can be easily improved. In addition, conventionally, since the energy ray-curable pressure-sensitive adhesive used in the surface protective sheet is easy to adjust the adhesion and easy to secure the burying property of the bumps, an acrylic type is mainly used.

Patent No. 4603578 Patent No. 4918181 gazette Patent No. 4367769

By the way, in recent years, along with the further densification and miniaturization of semiconductor devices, the height of bumps tends to be high, and those having a height of 200 μm or more are being studied. However, when using the acrylic surface protection sheet described in Patent Document 3 for a semiconductor wafer having a large bump height and a large height difference, an adhesive residue (adhesive residue) is generated on the bump when the sheet is peeled off. There may be many occurrences. This is because acrylic energy ray-curable pressure-sensitive adhesives have relatively low cohesion and mechanical strength.
On the other hand, for example, in Patent Literatures 1 and 2, using a material other than an acrylic pressure-sensitive adhesive such as a polyurethane-based elastomer for the application surface of the surface protective sheet is examined. However, patent documents 1 and 2 do not necessarily consider the application to the energy beam curing type adhesive of those materials, and further improvement is needed in order to secure adhesiveness, exfoliation nature, and the embeddability of bump. is necessary.

  The present invention has been made in view of the above situation, and the subject of the present invention is to the surface shape of a work represented by adhesion to a work such as a semiconductor wafer, peelability, and burying property of a bump. It is an object of the present invention to provide a pressure-sensitive adhesive tape for processing a work with little adhesive residue on the surface of a work even if the work to be attached has a non-flat surface shape while improving the followability of the pressure-sensitive adhesive layer.

MEANS TO SOLVE THE PROBLEM The present inventors discovered that the said subject could be solved by using a urethane type adhesive as an adhesive and making the composition into a specific thing as a result of earnest examination, and completed the following this invention. The present invention provides the pressure-sensitive adhesive tape for work processing of the following (1) to (16).
(1) A substrate, and an adhesive layer provided on one side of the substrate,
The energy ray-curable compound wherein the pressure-sensitive adhesive layer is non-reactive with the urethane resin (A) and the urethane resin (A) and has a photopolymerizable unsaturated bond and a molecular weight of 35,000 or less (B) and an adhesive tape for processing a work.
(2) The work processing as described in the above (1), wherein the energy ray curable compound (B) is at least one selected from a (meth) acrylate monomer (B1) and a urethane (meth) acrylate (B2) Adhesive tape.
(3) The energy ray curable compound (B) contains at least a (meth) acrylate monomer (B1), and the (meth) acrylate monomer (B1) is a polyhydric alcohol and a complete of (meth) acrylic acid The adhesive tape for workpiece | work processing as described in said (2) which is polyfunctional (meth) acrylic acid ester which is ester.
(4) The adhesive tape for processing a work according to any one of the above (1) to (3), wherein the energy beam curable compound (B) has two or more (meth) acryloyl groups in one molecule.
(5) The adhesive tape for workpiece | work processing in any one of said (1)-(4) in which the said urethane type resin (A) has a photopolymerizable unsaturated bond.
(6) The pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing at least a urethane polymer (A ′), the energy ray-curable compound (B), and a crosslinking agent (C),
The adhesive tape for workpiece | work processing in any one of said (1)-(5) whose said urethane type resin (A) is what bridge | crosslinked urethane polymer (A ') by the said crosslinking agent (C).
(7) The adhesive tape for work processing as described in said (6) in which the said crosslinking agent (C) contains the crosslinking agent (C1) containing a photopolymerizable unsaturated bond.
(8) The adhesive tape for work processing as described in said (6) or (7) which has couple | bonded the said urethane polymer (A ') and the said crosslinking agent (C) by the urethane bond.
(9) The above (6) to (8), wherein the pressure-sensitive adhesive composition further contains a compound (D) having a photopolymerizable unsaturated bond and a reactive functional group capable of reacting with the crosslinking agent (C). The adhesive tape for processing a work according to any one of the above.
(10) The adhesive tape for work processing as described in said (9) whose said compound (D) is a polyhydric alcohol and the polyfunctional (meth) acrylic acid ester which is a partial ester of (meth) acrylic acid.
(11) The adhesive tape for workpiece | work processing in any one of said (1)-(10) whose breaking stress after energy-beam irradiation of the said adhesive layer is 2.5 Mpa or more.
(12) The adhesive tape for work processing according to any one of the above (1) to (11), which has an intermediate layer between the substrate and the adhesive layer.
(13) The adhesive tape for workpiece processing as described in said (12) whose thickness of the said intermediate | middle layer is 10-600 micrometers.
(14) The adhesive tape for work processing as described in the above (12) or (13), wherein the intermediate layer has a loss tangent at 50 ° C. measured at a frequency of 1 Hz of 1.0 or more.
(15) The adhesive tape for workpiece | work processing in any one of said (1)-(14) whose adhesive force after energy-beam irradiation is 2000 mN / 25 mm or less.
(16) The adhesive tape for workpiece | work processing in any one of said (1)-(15) which is an adhesive tape for semiconductor wafer surface protection.

  In the present invention, it is possible to provide a pressure-sensitive adhesive tape for processing a work with a small amount of adhesive residue on the work surface, while improving the tackiness, releasability, and the followability of the pressure-sensitive adhesive layer to the surface shape of the work.

In the following description, "weight average molecular weight (Mw)" is a value in terms of polystyrene measured by gel permeation chromatography (GPC), and specifically, it was measured based on the method described in the examples. It is a value.
Moreover, in the description in the present specification, for example, “(meth) acrylate” is used as a term indicating both “acrylate” and “methacrylate”, and the same applies to other similar terms.

Hereinafter, the present invention will be described using embodiments.
The pressure-sensitive adhesive tape for processing a work of the present invention (hereinafter, also simply referred to as "pressure-sensitive adhesive tape") comprises a substrate and a pressure-sensitive adhesive layer provided on one side of the substrate. Moreover, the adhesive tape may have an intermediate | middle layer between this base material and an adhesive layer. An adhesive tape may be comprised from 2 layers or 3 layers as mentioned above, and also another layer may be provided. For example, a release material may be further provided on the pressure-sensitive adhesive layer.
Hereinafter, each member which comprises an adhesive tape is demonstrated in detail.

<Base material>
Although the base material used for an adhesive tape is not specifically limited, It is preferable that it is a resin film. A resin film is suitable for a processed member of an electronic component because it generates less dust compared to paper and non-woven fabric, and it is preferable because it is easy to obtain. The substrate may be a single layer film composed of one resin film, or may be a multilayer film in which a plurality of resin films are laminated.
As a resin film used as a base material, for example, polyolefin film, halogenated vinyl polymer film, acrylic resin film, rubber film, cellulose film, polyester film, polycarbonate film, polystyrene film, polyphenylene sulfide Examples include film-based films and cycloolefin polymer-based films.
Among these, polyester-based films are preferable from the viewpoint of being able to stably hold the wafer when grinding the wafer to an extremely thin thickness, and from the viewpoint of being a film with high thickness accuracy, among polyester-based films, A polyethylene terephthalate film is preferred from the viewpoint of easy availability and high thickness accuracy.
The thickness of the substrate is not particularly limited, but is preferably 10 to 200 μm, more preferably 25 to 150 μm.

  From the viewpoint of improving the adhesion of the substrate to the pressure-sensitive adhesive layer or the intermediate layer, a substrate obtained by further laminating an easy adhesion layer or a pressure-sensitive adhesive layer on the surface of the resin film may be used. Furthermore, the base material used in the present invention may contain a filler, a colorant, an antistatic agent, an antioxidant, an organic lubricant, a catalyst, and the like as long as the effects of the present invention are not impaired. The substrate may be transparent or colored if desired, but it is preferred to transmit energy rays to an extent sufficient to cure the pressure-sensitive adhesive layer.

<Middle class>
In the pressure-sensitive adhesive tape of the present invention, an intermediate layer may be provided on one side of the substrate. The pressure-sensitive adhesive tape according to the present invention has the intermediate layer, so that bumps are provided on the work, and even if the height difference of the irregularities on the work surface is large, the convex portions are embedded in the pressure-sensitive adhesive layer and the intermediate layer As a result, it is easy to keep the surface opposite to the surface of the adhesive tape that is attached to the work flat. The intermediate layer used in the present invention preferably has a loss tangent (tan δ) at 50 ° C. measured at a frequency of 1 Hz (hereinafter also simply referred to as “loss tangent”) of 1.0 or more.
When the loss tangent of the intermediate layer is such a value, when the pressure-sensitive adhesive tape for processing a work is attached to an uneven work such as a wafer with bumps, the intermediate layer is sufficiently deformed and can follow the unevenness easily. The loss tangent of the intermediate layer is more preferably 1.5 or more, still more preferably 1. from the viewpoint of sufficiently absorbing the unevenness such as bumps to obtain a good adhesion state to the surface of the bumped wafer, for example. It is 65 or more, more preferably 1.8 or more.
Further, from the viewpoint of adjusting the fluidity of the intermediate layer at the time of heating to an appropriate range, the loss tangent of the intermediate layer is preferably 5.0 or less, more preferably 4.0 or less.
More specifically, the loss tangent of the intermediate layer described above is a value measured based on the method described in the examples to be described later.

  The thickness of the intermediate layer can be appropriately adjusted according to the state of the adherend surface to which the adhesive tape is to be applied, but is preferably from the viewpoint of being able to absorb relatively high bumps as well. Is 10 to 600 μm, more preferably 25 to 550 μm, and still more preferably 35 to 500 μm.

The intermediate layer is formed of the intermediate layer resin composition. Moreover, it is preferable that the resin composition for intermediate | middle layers contains a urethane (meth) acrylate.
(Urethane (meth) acrylate (X))
The urethane (meth) acrylate (X) is a compound having at least a (meth) acryloyl group and a urethane bond, and has a property of polymerizing by energy ray irradiation. In addition, an energy ray is what has an energy quantum in electromagnetic waves or a charged particle beam, and points out active light, such as an ultraviolet ray, or an electron beam.
The number of (meth) acryloyl groups in the urethane (meth) acrylate (X) may be monofunctional, bifunctional or trifunctional or higher, but in order to facilitate the loss tangent to be 1.0 or more, the resin composition for an intermediate layer It is preferred that the monofunctional urethane (meth) acrylate is contained. Since the monofunctional urethane (meth) acrylate does not participate in the formation of the three-dimensional network structure in the polymerization structure, the three-dimensional network structure is less likely to be formed in the intermediate layer, and the loss tangent is easily enhanced.

  As urethane (meth) acrylate (X) used for the resin composition for intermediate | middle layers, it has a (meth) acryloyl group, for example in the terminal isocyanate urethane prepolymer obtained by making a polyol compound and a polyisocyanate compound react. It can be obtained by reacting a compound. The urethane (meth) acrylate (X) may be used alone or in combination of two or more.

[Polyol compound]
The polyol compound is not particularly limited as long as it is a compound having two or more hydroxy groups.
As a specific polyol compound, an alkylene diol, a polyether type polyol, a polyester type polyol, a polycarbonate type polyol etc. are mentioned, for example.
Among these, polyether type polyols are preferable.
The polyol compound may be any of a difunctional diol, a trifunctional triol, and a tetrafunctional or higher functional polyol, but from the viewpoint of availability, versatility, reactivity, etc., a difunctional diol Are preferred, and polyether type diols are more preferred.

The polyether type diol is preferably a compound represented by the following formula (1).

In said Formula (1), although R is a bivalent hydrocarbon group, an alkylene group is preferable and a C1-C6 alkylene group is more preferable. Among the alkylene groups having 1 to 6 carbon atoms, an ethylene group, a propylene group and a tetramethylene group are preferable, and a propylene group and a tetramethylene group are more preferable.
Moreover, n is the number of repeating units of alkylene oxide, Preferably it is 10-250, More preferably, it is 25-205, More preferably, it is 40-185. If n is in the above range, the concentration of urethane bonds in the resulting urethane (meth) acrylate is made appropriate, and it becomes easy to prepare the intermediate layer so that the loss tangent satisfies the above requirements.
Among the compounds represented by the above formula (1), polyethylene glycol, polypropylene glycol and polytetramethylene glycol are preferable, and polypropylene glycol and polytetramethylene glycol are more preferable.
The reaction between the polyether type diol and the polyisocyanate compound produces a terminal isocyanate urethane prepolymer in which an ether bond [-(-RO-) n-] is introduced. By using such a polyether type diol, urethane (meth) acrylate contains the structural unit derived from polyether type diol.

A polyester type polyol is obtained by polycondensing a polyol component and a polybasic acid component. As a polyol component, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-Methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, hexanediol, octanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2 -Various known glycols such as -butyl 1,3-propanediol, 1,4-cyclohexanedimethanol, ethylene glycol or propylene glycol adduct of bisphenol A, and the like can be mentioned.
As the polybasic acid component used for producing a polyester type polyol, compounds generally known as polybasic acid components of polyester can be used.
Specific polybasic acid components include, for example, dibasic acids such as adipic acid, maleic acid, succinic acid, oxalic acid, fumaric acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, suberic acid and the like; Aromatic polybasic acids such as dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid and 2,6-naphthalenedicarboxylic acid, and polybasic acids such as trimellitic acid and pyromellitic acid, corresponding anhydrides and the like Its derivatives and dimer acids, hydrogenated dimer acids and the like can be mentioned. Among these, from the viewpoint of forming a coating film having appropriate hardness, aromatic polybasic acids are preferable. For the esterification reaction for producing a polyester type polyol, various known catalysts may be used, if necessary.
The polycarbonate-type polyol is not particularly limited, and examples thereof include the above-mentioned reaction products of glycols and alkylene carbonate.

The number average molecular weight calculated from the hydroxyl value of the polyol compound is preferably 1,000 to 10,000, more preferably 2,000 to 9,000, and still more preferably 3,000 to 7,000. If the said number average molecular weight is 1,000 or more, since the situation that control of the viscoelastic property of an intermediate | middle layer becomes difficult due to the production | generation of an excessive amount of urethane bond is avoided, it is preferable. On the other hand, if the said number average molecular weight is 10,000 or less, since it can prevent that the intermediate | middle layer obtained softens excessively, it is preferable.
The number average molecular weight calculated from the hydroxyl value of the polyol compound is a value calculated from [number of polyol functional groups] × 56.11 × 1000 / [hydroxy value (unit: mg KOH / g)].

[Polyisocyanate compound]
Examples of the polyisocyanate compound include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4 ' Alicyclic diisocyanates such as diisocyanate, ω, ω′-diisocyanatodimethylcyclohexane; 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, naphthalene-1,5- Aromatic diisocyanates, such as diisocyanate, etc. are mentioned.
Among these, isophorone diisocyanate, hexamethylene diisocyanate and xylylene diisocyanate are preferable from the viewpoint of handleability.

{Compounds having (meth) acryloyl group}
As a compound which has a (meth) acryloyl group, the (meth) acrylate which has a hydroxyl group is mentioned. The (meth) acrylate having a hydroxy group is not particularly limited as long as it is a compound having a hydroxy group and a (meth) acryloyl group in at least one molecule.
Specific (meth) acrylates having a hydroxy group include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 4-hydroxycyclohexyl (meth) Acrylate, 5-hydroxycyclooctyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, etc. Hydroxyalkyl (meth) acrylates; hydroxy group-containing (meth) acrylamides such as N-methylol (meth) acrylamide; vinyl alcohol, vinyl phenol, bisphenol The reaction product obtained by the diglycidyl ester of Nord A (meth) acrylic acid is reacted, and the like.
Among these, hydroxyalkyl (meth) acrylate is preferable, and 2-hydroxyethyl (meth) acrylate is more preferable.

The weight average molecular weight of the urethane (meth) acrylate (X) for the intermediate layer resin composition thus obtained is preferably 1,000 to 100,000, more preferably 3,000 to 80,000, and further more preferably Preferably, it is 5,000 to 65,000. If the said weight average molecular weight is 1,000 or more, in the polymer of urethane (meth) acrylate and the polymerizable monomer mentioned later, it originates in the intermolecular force of the structures derived from urethane (meth) acrylate, It is preferable because the intermediate layer is given a suitable hardness.
The compounding amount of the urethane (meth) acrylate (X) in the resin composition for the intermediate layer is preferably 20 to 70% by mass, more preferably 25 to 60% by mass, still more preferably 30 to 50, based on the total amount of the composition. % By mass, more preferably 33 to 47% by mass. When the amount of the urethane (meth) acrylate is in such a range, an intermediate layer having a high loss tangent can be easily formed.

The resin composition for the intermediate layer further contains, for example, a thiol group-containing compound (Y) or a polymerizable monomer (Z) in addition to the above urethane (meth) acrylate (X), but contains both of them. It is preferable to do.
(Thiol group-containing compound (Y))
The thiol group-containing compound (Y) is not particularly limited as long as it is a compound having at least one thiol group in the molecule, but a polyfunctional thiol group-containing compound is preferable from the viewpoint of facilitating loss tangent. A tetrafunctional thiol group-containing compound is more preferred.
Specific examples of the thiol group-containing compound (Y) include nonylmercaptan, 1-dodecanethiol, 1,2-ethanedithiol, 1,3-propanedithiol, triazinethiol, triazinedithiol, triazinetrithiol, 1, 2 , 3-propanetrithiol, tetraethylene glycol-bis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakisthio Glucolate, dipentaerythritol hexakis (3-mercaptopropionate), tris [(3-mercaptopropionyloxy) -ethyl] -isocyanurate, 1,4-bis (3-mercaptobutyryloxy) Butane, pentaerythritol tetrakis (3-mercaptobutyrate), 1,3,5-tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2,4,6- (1H, 3H, 5H) -Trion etc. are mentioned.
These thiol group-containing compounds (Y) may be used alone or in combination of two or more.

The molecular weight of the thiol group-containing compound (Y) is preferably 200 to 3,000, more preferably 300 to 2,000. If the said molecular weight is the said range, compatibility with urethane (meth) acrylate (X) will become favorable, and film forming property can be made favorable.
The compounding amount of the thiol group-containing compound (Y) is preferably 1.0 to 4.9 parts by mass with respect to 100 parts by mass in total of the urethane (meth) acrylate (X) and the polymerizable monomer (Z) described later. Part, more preferably 1.5 to 4.8 parts by mass.
If the said compounding quantity is 1.0 mass part or more, it will become easy to form the intermediate | middle layer with a high loss tangent, and pump absorbency can be improved. On the other hand, if the said compounding quantity is 4.9 mass parts or less, the penetration of the intermediate | middle layer at the time of winding up in roll shape etc. can be suppressed.

(Polymerizable monomer (Z))
It is preferable that the resin composition for an intermediate layer used in the present invention further contain a polymerizable monomer (Z) from the viewpoint of improving the film forming property. The polymerizable monomer (Z) is a polymerizable compound other than the above-mentioned urethane (meth) acrylate (X), and is a compound capable of polymerizing with other components by irradiation of energy rays. However, the polymerizable monomer (Z) means one excluding the resin component. The polymerizable monomer (Z) is preferably a compound having at least one (meth) acryloyl group.
In addition, in this specification, a "resin component" refers to the oligomer or high molecular weight body which has a repeating structure in a structure, and a weight average molecular weight means the compound of 1,000 or more.

  As the polymerizable monomer (Z), for example, alkyl (meth) acrylate having an alkyl group having 1 to 30 carbon atoms, (meth) acrylate having a functional group such as a hydroxyl group, an amido group, an amino group or an epoxy group (Meth) acrylate having an alicyclic structure, (meth) acrylate having an aromatic structure, (meth) acrylate having a heterocyclic structure, styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinyl formamide, N-vinyl form Examples thereof include vinyl compounds such as pyrrolidone, N-vinylcaprolactam, allyl glycidyl ether and the like.

  Examples of the alkyl (meth) acrylate having an alkyl group having 1 to 30 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl Meta) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, Nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, hexadecyl (meth) acrylate, octade Le (meth) acrylate, eicosyl (meth) acrylate.

  As the (meth) acrylate having a functional group, for example, hydroxyl group-containing (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate and the like; (meth) acrylamide, N, N -Dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylol propane (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, etc. Amide group-containing compounds; amino group-containing (meth) acrylates such as primary amino group-containing (meth) acrylates, secondary amino group-containing (meth) acrylates, and tertiary amino group-containing (meth) acrylates; Meta) Relate, and containing epoxy groups such as methyl glycidyl (meth) acrylate (meth) acrylate.

Examples of (meth) acrylates having an alicyclic structure include isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, etc. ) Acrylate, adamantane (meth) acrylate and the like.
Examples of (meth) acrylates having an aromatic structure include phenylhydroxypropyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate and the like.
Examples of (meth) acrylates having a heterocyclic structure include tetrahydrofurfuryl (meth) acrylate and morpholine (meth) acrylate.

  Among these, from the viewpoint of compatibility with the above urethane (meth) acrylate (X), those having a relatively bulky group are preferable, and more specifically, (meth) acrylates having an alicyclic structure, (Meth) acrylates having an aromatic structure and (meth) acrylates having a heterocyclic structure are preferable, and (meth) acrylates having an alicyclic structure are more preferable. Further, from the viewpoint of facilitating the loss tangent to be 1.0 or more, it is preferable to contain a (meth) acrylate having a functional group and a (meth) acrylate having an alicyclic structure as a polymerizable monomer, More preferably, it comprises meta) acrylate and isobornyl (meth) acrylate.

The compounding amount of the (meth) acrylate having an alicyclic structure in the resin composition for the intermediate layer is preferably 32 to 53% by mass, more preferably 35 to 51% by mass on the basis of the total amount of the composition from the above viewpoint. More preferably, it is 37 to 48% by mass, still more preferably 40 to 47% by mass.
Moreover, the compounding quantity of the (meth) acrylate which has an alicyclic structure with respect to the whole quantity of the polymerizable monomer (Z) contained in the resin composition for intermediate | middle layers is preferably 52-87 mass% from the said viewpoint. More preferably, it is 55-85 mass%, More preferably, it is 60-80 mass%, More preferably, it is 65-77 mass%. It becomes easy to make a loss tangent 1.0 or more as the compounding quantity of the (meth) acrylate which has an alicyclic structure is such a range.

Moreover, the compounding quantity of the polymerizable monomer (Z) in the resin composition for intermediate | middle layers becomes like this. Preferably it is 30-80 mass%, More preferably, it is 40-75 mass%, More preferably, it is 50-70 mass%, More More preferably, it is 53 to 67% by mass. When the content of the polymerizable monomer (Z) is in such a range, the mobility of the portion formed by the polymerization of the polymerizable monomer (Z) in the intermediate layer is high, so the intermediate layer is flexible. It becomes easier to form an intermediate layer in which the loss tangent meets the above requirements.
Further, from the same viewpoint, the mass ratio [urethane (meth) acrylate / polymerizable monomer] of urethane (meth) acrylate (X) and polymerizable monomer (Z) in the resin composition for the intermediate layer is , Preferably 20/80 to 60/40, more preferably 30/70 to 50/50, still more preferably 35/65 to 45/55.

(Energy ray polymerization initiator (R))
The resin composition for the intermediate layer preferably further contains an energy ray polymerization initiator (R). By containing the energy ray polymerization initiator (R), the resin composition for an intermediate layer can be easily cured by energy rays such as ultraviolet rays. The energy ray polymerization initiator (R) is also generally referred to as “photoinitiator”, and hence, in the present specification, is also simply referred to as “photoinitiator” hereinafter.
Examples of the photopolymerization initiator include photopolymerization initiators such as benzoin compounds, acetophenone compounds, acyl phosphinoxide compounds, titanocene compounds, thioxanthone compounds and peroxide compounds, and photosensitizers such as amines and quinones. More specifically, for example, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, 2 , 2-dimethoxy-1,2-diphenylethane-1-one and the like.
You may use these photoinitiators 1 type or in combination of 2 or more types.
The compounding amount of the photopolymerization initiator is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass with respect to a total of 100 parts by mass of the urethane (meth) acrylate and the polymerizable monomer. More preferably, it is 0.3 to 5 parts by mass.

(Other additives)
The interlayer resin composition may contain other additives as long as the effects of the present invention are not impaired. Examples of other additives include crosslinking agents, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes and the like. When these additives are blended, the blending amount of the other additives is preferably 0.01 to 6 parts by mass, more preferably 100 parts by mass in total of the urethane (meth) acrylate and the polymerizable monomer. Is 0.1 to 3 parts by mass.
In addition, although the resin composition for intermediate | middle layers may contain resin components other than urethane (meth) acrylate in addition to urethane (meth) acrylate in the range which does not impair the effect of this invention, urethane as a resin component It is preferable to contain only (meth) acrylate.
The content of the resin component other than urethane (meth) acrylate contained in the resin composition for the intermediate layer is preferably 5% by mass or less, more preferably 1% by mass or less, still more preferably 0.1% by mass or less More preferably, it is 0 mass%.

  Further, the intermediate layer may be formed of a resin composition for an intermediate layer containing another resin component instead of urethane (meth) acrylate (X). For example, the intermediate layer may be formed using a curable composition containing a non-reactive urethane polymer or oligomer and a polymerizable monomer, or a composition containing an ethylene-α-olefin copolymer. . As the non-reactive urethane polymer or oligomer, a known one may be used, and as the polymerizable monomer, the same one as described above can be used. Such a curable composition may contain the energy beam polymerization initiator described above.

The ethylene-α-olefin copolymer is obtained by polymerizing ethylene and an α-olefin monomer. As the α-olefin monomer, propylene, 1-butene, 2-methyl-1-butene, 2-methyl-1-pentene, 1-hexene, 2,2-dimethyl-1-butene, 2-methyl-1-hexene , 4-Methyl-1-pentene, 1-heptene, 3-methyl-1-hexene, 2,2-dimethyl-1-pentene, 3,3-dimethyl-1-pentene, 2,3-dimethyl-1-pentene 3-ethyl-1-pentene, 2,2,3-trimethyl-1-butene, 1-octene, 2,2,4-trimethyl-1-octene and the like. These α-olefin monomers can be used alone or in combination of two or more.
The ethylene-α-olefin copolymer may be one obtained by polymerizing ethylene, an α-olefin monomer and another monomer. Other monomer components include, for example, vinyl compounds such as vinyl acetate, styrene, acrylonitrile, methacrylonitrile and vinyl ketone; unsaturated carboxylic acids such as acrylic acid and methacrylic acid; methyl acrylate, ethyl acrylate, acrylic acid-n -Unsaturated carboxylic acid esters such as propyl, methyl methacrylate, ethyl methacrylate and n-propyl methacrylic acid; and unsaturated carboxylic acid amides such as acrylamide and methacrylamide. These monomers can be used alone or in combination of two or more.

<Pressure-sensitive adhesive layer>
The pressure-sensitive adhesive layer is provided on the substrate and, if provided, on the intermediate layer. The pressure-sensitive adhesive layer of the present invention contains at least a urethane resin (A) and an energy ray-curable compound (B) which is non-reactive with the urethane resin (A) and has a molecular weight of 35,000 or less.
In the present invention, when the pressure-sensitive adhesive layer contains the urethane resin (A), the cohesion and mechanical strength of the pressure-sensitive adhesive layer become high. Adhesive residue is less likely to occur on the workpiece surface. In addition, the pressure-sensitive adhesive layer has energy ray curability by containing at least the energy ray curable compound (B). Therefore, the peeling performance at the time of peeling an adhesive tape from a work becomes favorable. Furthermore, since the energy ray-curable compound (B) is non-reactive, as described later, the storage elastic modulus of the pressure-sensitive adhesive layer becomes low, and the followability to the unevenness of the work surface can be easily secured.

The pressure-sensitive adhesive layer preferably has a breaking stress of 2.5 MPa or more after energy beam irradiation. When the breaking stress is 2.5 MPa or more, the mechanical strength becomes a sufficient value, and the above-described adhesive residue can be easily reduced. In addition, the breaking stress is preferably 2.8 to 30 MPa, more preferably 3.0 to 25 MPa, from the viewpoint of easily improving the embedding property of the projections, the adhesiveness of the pressure-sensitive adhesive layer and the releasability while suppressing the adhesive residue. is there. In addition, breaking stress is measured by the method as described in the Example mentioned later.
The breaking stress can be adjusted by changing the type of urethane resin (A). The stress can be adjusted also by the amount of the photopolymerizable unsaturated bond described later, and the breaking stress increases as the amount of the photopolymerizable unsaturated bond contained in the adhesive layer increases, and the breaking stress decreases as the amount decreases. There is a tendency. Similarly, the amount can also be adjusted by the amount of the crosslinking agent component described later. The breaking stress increases as the amount of the crosslinking agent component increases, and the breaking stress tends to decrease as the amount decreases.

Since the pressure-sensitive adhesive layer is energy beam curable, it can be made relatively soft before energy beam irradiation, and the pressure-sensitive adhesive layer can easily follow the unevenness formed on the work surface. In addition, the adhesive tape is reduced in adhesive power by being irradiated with energy beam and hardened, and is easily peeled off from the work.
It is preferable that the adhesive force after energy-beam irradiation of an adhesive tape is 2000 mN / 25 mm or less from a viewpoint of suppressing the adhesive residue at the time of peeling of an adhesive tape. In particular, when the pressure-sensitive adhesive tape of the present invention having an intermediate layer is attached to a work having large protrusions (for example, a height of 200 μm or more) such as bumps on the surface, usually the pressure-sensitive adhesive tape with the protrusions attached to the work surface Absorbed by the middle layer of the Therefore, adhesive residue is easily generated when the adhesive tape is peeled therefrom, but generation of such adhesive residue can be easily prevented by setting the adhesive force to 2000 mN / 25 mm or less. The adhesive strength of the adhesive tape after energy beam irradiation is preferably 50 to 1750 mN / 25 mm, more preferably 100 to 1500 nN / 25 mm.

The adhesive strength of the adhesive tape before energy beam irradiation is, for example, larger than 2000 mN / 25 mm, preferably 3,000 to 30,000 mN / 25 mm, more preferably 3,500 to 9,000 mN / m. When the adhesion before energy beam irradiation is in such a range, the adhesion to the surface of the work becomes good, and the protection performance of the work becomes good.
The adhesive strength of the adhesive tape is measured when the adhesive layer side of the adhesive tape is attached to a silicon mirror wafer and peeled at a peeling angle of 180 ° and a peeling speed of 300 mm / min in an environment of 23 ° C. Specifically, it is measured by the method described in the examples described later.
The adhesive strength can be adjusted by changing the types of the urethane resin (A) and the energy ray curable compound (B). In addition, the adhesion after energy beam irradiation can be adjusted also by the amount of photopolymerizable unsaturated bonds described later, and decreases as the amount of photopolymerizable unsaturated bonds contained in the adhesive composition increases. It tends to become high if it decreases. Furthermore, the adhesion after energy beam irradiation can be easily lowered by blending a crosslinking agent (C1) or compound (D) containing a photopolymerizable unsaturated bond as described later.

(Urethane resin (A))
The urethane resin (A) is a polymer containing at least one of a urethane bond and a urea bond. Further, the pressure-sensitive adhesive layer of the present invention is prepared from a urethane-based pressure-sensitive adhesive composition containing at least a urethane polymer (A ′) and an energy ray-curable compound (B) (hereinafter, also simply referred to as “pressure-sensitive adhesive composition”). The urethane resin (A) is formed of at least a urethane polymer (A ') which is a main component. Moreover, a crosslinking agent (C), a compound (D), etc. are further contained in the urethane type adhesive composition as needed.

The urethane resin (A) may be crosslinked by a crosslinking agent (C). Further, as described above, the urethane-based pressure-sensitive adhesive composition may be bonded directly or indirectly to the urethane polymer (A ′) as in the compound (D), etc., in addition to the crosslinking agent (C). You may contain the compound which comprises a urethane type resin (A) as integral in a layer.
In addition, as in the crosslinker (C) and the compound (D), a urethane resin (in combination with the urethane polymer (A ′) in the pressure-sensitive adhesive layer) is directly or indirectly bonded to the urethane polymer (A ′). The compounds constituting A) are collectively referred to as "main agent reactive compounds".
In the present invention, the compounding amount of the urethane polymer (A ′) is the total amount of the pressure-sensitive adhesive composition in order to mix components (B) to (E) described later in appropriate amounts while securing the adhesiveness of the pressure-sensitive adhesive layer. Preferably it is 30-85 mass%, More preferably, it is 35-80 mass%, More preferably, it is 37-77 mass%. The total content of the main agent reactive compound and the urethane polymer (A ') is preferably 40 to 95% by mass, more preferably 45 to 94% by mass, and still more preferably 50 to 50% by mass based on the total amount of the pressure-sensitive adhesive composition. It is 93% by mass.

  The urethane resin (A) preferably has a photopolymerizable unsaturated bond. When the urethane-based resin (A) has a photopolymerizable unsaturated bond, both the urethane-based resin (A) and the energy ray-curable compound (B) in the pressure-sensitive adhesive layer of the adhesive tape for processing a work It will have a polymerizable unsaturated bond. Therefore, by irradiating the pressure-sensitive adhesive layer with energy rays, a bond is formed between the urethane resin (A) and the energy ray-curable compound (B) by polymerization reaction, and adhesion of the pressure-sensitive adhesive tape after energy rays irradiation The force is more easily reduced, and the peelability at the time of peeling the adhesive tape from the work is improved. Furthermore, it becomes possible to further reduce the adhesive residue generated when the adhesive tape is peeled from the work. In addition, the strength of the pressure-sensitive adhesive layer after energy ray irradiation tends to be higher than when curing of the pressure-sensitive adhesive layer by energy ray irradiation is caused only by the energy ray-curable compound (B), It is easier to suppress the occurrence.

The method for introducing a photopolymerizable unsaturated bond into the urethane resin (A) is not particularly limited. For example, when the urethane polymer (A ′) before introduction of the photopolymerizable unsaturated bond has a hydroxyl group, a functional group capable of reacting with the hydroxyl group and a function containing a photopolymerizable unsaturated bond such as (meth) acryloyl group It is possible to react a compound having a group with the above-mentioned hydroxyl group to introduce a photopolymerizable unsaturated bond. Examples of the compound having a functional group capable of reacting with a hydroxyl group and a functional group containing a photopolymerizable unsaturated bond include methacryloyloxyethyl isocyanate and the like. Such a compound may be reacted in advance with the urethane polymer (A ′), or may be contained in the adhesive layer and reacted with the urethane polymer (A ′) at the time of forming the adhesive layer. .
Further, as described later, the urethane polymer (A ′) is crosslinked by using a crosslinking agent (C1) having a photopolymerizable unsaturated bond as the crosslinking agent (C) to form a urethane resin (A) as a light. A polymerizable unsaturated bond may be introduced. Furthermore, a photopolymerizable unsaturated bond may be introduced into the urethane resin (A) by a compound (D) described later.

<Urethane polymer (A ')>
The urethane polymer (A ′) includes one containing at least one of a urethane bond and a urea bond, and specifically, a polyurethane polyol having a hydroxyl group at an end obtained by reacting a polyol and a polyisocyanate compound. . The urethane polymer (A ′) may be obtained by reacting a polyol and a polyisocyanate compound, and a urethane polymer having an isocyanate terminal may be used.

The polyols used for the urethane polymer (A ′) include polyester polyols and polyether polyols.
A known polyester polyol is used as the polyester polyol. The polyester polyol is an ester of an acid component and at least one of a glycol component and a polyol component, and as the acid component, terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, trimellitic acid etc. It can be mentioned. Also, as a glycol component, ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxy acid Propylene glycol, 1,4-butanediol, neopentyl glycol, butylethyl pentanediol are mentioned, and glycerin, trimethylolpropane, pentaerythritol etc. are mentioned as a polyol component.
In addition, polyesterpolyol obtained by ring-opening polymerization of lactones such as polycaprolactone, poly (β-methyl-γ-valerolactone) and polyvalerolactone may be used.

  In addition, as the polyether polyol, a known polyether polyol is used. For example, a polyether polyol obtained by polymerizing an oxirane compound such as ethylene oxide, propylene oxide, butylene oxide, or tetrahydrofuran using a low molecular weight polyol such as water, propylene glycol, ethylene glycol, glycerin, or trimethylolpropane as an initiator. Specifically, those having two or more functional groups such as polypropylene glycol, polyethylene glycol, polytetramethylene glycol and the like are used.

  As a polyisocyanate compound, well-known aromatic polyisocyanate, aliphatic polyisocyanate, araliphatic polyisocyanate, alicyclic polyisocyanate etc. are mentioned. As aromatic polyisocyanates, 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate Isocyanate, 4,4′-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanatobenzene, dianisidine diisocyanate, 4,4′-diphenylether diisocyanate, 4,4 ′, 4 ′ ′- Triphenyl methane triisocyanate etc. can be mentioned.

  As aliphatic polyisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4 And 4-trimethylhexamethylene diisocyanate etc. can be mentioned.

  As the araliphatic polyisocyanate, ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene, 1, 4- tetramethyl xylylene diisocyanate, 1, 3- tetramethyl xylylene diisocyanate, etc. can be mentioned.

As the alicyclic polyisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentadiisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4- Examples include cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylene bis (cyclohexyl isocyanate), 1,4-bis (isocyanate methyl) cyclohexane, 1,4-bis (isocyanate methyl) cyclohexane and the like. .
The above polyisocyanate compound can be used in combination with the trimethylolpropane adduct of the above polyisocyanate compound, a biuret reacted with water, a trimer having an isocyanurate ring, and the like.
As the polyisocyanate compound, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate (isophorone diisocyanate) and the like are preferable.

In addition to the polyol and the polyfunctional isocyanate, the polyurethane polyol may be obtained by further reacting a diamine such as ethylene diamine, N-aminoethyl ethanolamine, isophorone diamine, xylylene diamine and the like. Furthermore, as the polyol, in addition to the above-mentioned polyester polyol and polyether polyol, ethylene glycol, 1,4-butanediol, neopentyl glycol, butylethyl pentanediol, glycerin, trimethylolpropane, pentaerythritol etc. are used. It is also good.
The reaction with the polyol and the polyisocyanate compound is usually carried out in the presence of a catalyst such as a tertiary amine compound or an organic metal compound.

The urethane polymer (A ′) is not limited to those described above, and may be, for example, a Michael addition type urethane polymer.
Examples of the Michael addition type urethane polymer include the following (1) and (2).
(1) A urethane prepolymer having an isocyanate group (-NCO) at an end, which is obtained by reacting the above-mentioned polyol and a polyisocyanate compound, is reacted with an amino compound formed by the Michael addition reaction of a polyamine and an unsaturated compound. What will be
(2) A product obtained by reacting a polyamine in addition to the above-mentioned polyol and polyisocyanate compound and obtained by subjecting an unsaturated compound to a Michael addition reaction to a polyurethaneurea having a primary or secondary amino group at the end.

As the polyamine used in the Michael addition type urethane polymer, known ones can be used. Specifically, ethylene diamine, propylene diamine, trimethylene diamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, tri Aliphatic polyamines such as ethylenetetramine, diethylenetriamine, triaminopropane, 2,2,4-trimethylhexamethylenediamine, tolylenediamine, hydrazine, piperazine etc., cycloaliphatic such as isophorone diamine, dicyclohexylmethane-4,4'-diamine etc. Polyamines and aromatic polyamines such as phenylenediamine and xylylenediamine can be mentioned. Furthermore, 2-hydroxyethyl ethylene diamine, N- (2-hydroxyethyl) propylene diamine, (2-hydroxyethyl propylene) diamine, (di-2-hydroxyethyl ethylene) diamine, (di-2- hydroxyethyl propylene) diamine , (2-hydroxypropylethylene) diamine, (di-2-hydroxypropylethylene) diamine, etc. Diamine diamine having hydroxyl group in molecule and dimer acid obtained by converting carboxyl group of dimer acid to amino group, propoxyamine at both ends And polyoxyalkylene glycol diamines represented by the following general formula (2) can also be used.
H ₂ -NCH ₂ -CH ₂ -CH ₂ -O (C _n H _{2 n} -O) _m -CH ₂ -CH ₂ -CH ₂ -NH ₂ (2)
(In the formula (2), n represents an arbitrary integer of 2 to 4 and m represents an arbitrary integer of 2 to 50.)
Furthermore, dendrimers having primary or secondary amino groups at the end can also be used as polyamines.
Among the above-mentioned polyamines, isophorone diamine, 2,2,4-trimethylhexamethylene diamine and hexamethylene diamine are preferable from the viewpoint of easy control of the reaction.

Also, the unsaturated compound used in the Michael addition type urethane polymer is used for the purpose of modifying the urethane polymer. Therefore, the type of unsaturated compound to be used can be arbitrarily selected according to the purpose of modification. Examples of unsaturated compounds include (meth) acrylic unsaturated compounds, amide unsaturated compounds, fatty acid vinyl unsaturated compounds, vinyl ether unsaturated compounds, α-olefin unsaturated compounds, allyl unsaturated compounds, acetic acid Examples thereof include allyl-based unsaturated compounds, vinyl cyanide-based unsaturated compounds, styrene and vinylbenzene-based unsaturated compounds.
Although the kind of unsaturated compound to be used can be arbitrarily selected according to the objective of modification | denaturation, it is preferable to pay attention to the functional group which an unsaturated compound has, and to select. Examples of functional groups possessed by such unsaturated compounds include alkyl groups, polyalkylene glycol groups, alkoxy groups, phenoxy groups, hydroxyl groups, carboxyl groups, perfluoroalkyl groups, alkoxysilyl groups, epoxy groups, and further amide groups and dialkyls. Although nitrogen-containing groups such as amino groups and quaternary ammonium bases can be exemplified, it is preferable to have a hydroxyl group in order to make the urethane polymer (A ′) contain a hydroxyl group as described above.
In addition, as these, as a specific example of an unsaturated compound, what is described in Unexamined-Japanese-Patent No. 2002-121256 (European-publication publication EP1146061A1) is used, for example.

  The weight average molecular weight of the urethane polymer (A ') used in the present invention is preferably 10,000 to 300,000, and more preferably 30,000 to 150,000. By being 10,000 or more, the cohesion of the pressure-sensitive adhesive layer is improved, and the effect of suppressing higher adhesive residue can be obtained. In addition, when the pressure-sensitive adhesive composition is formed from the pressure-sensitive adhesive composition, by setting the amount to 300,000 or less, viscosity increase which affects the process suitability is caused even if it is diluted with a solvent or heated and melted. It has the advantage of being difficult.

(Energy ray curable compound (B))
The energy ray curable compound (B) used in the present invention is non-reactive with the urethane resin (A) and has a photopolymerizable unsaturated bond.
Here, non-reacting means that, in addition to the “photopolymerizable unsaturated bond”, not only the urethane polymer (A ′) but also the functional group reactive with the main agent reactive compound is not contained, and the compound (B) Is a compound which has not reacted with the urethane resin (A) in the pressure-sensitive adhesive layer.
That is, in the energy ray curable compound (B), the urethane polymer (A ′), the crosslinking agent (C), and the other components (eg, the component (D)) optionally used are reacted with each other. When the pressure-sensitive adhesive layer is formed, it is a compound which does not react with the components (A ′), (C) and (D).

Thus, the energy ray-curable compound (B) is present as a component that does not constitute the urethane resin (A) in the pressure-sensitive adhesive layer. Urethane polymers generally have high cohesion and high storage elastic modulus, so it is difficult to embed protrusions such as bumps on the surface of the work alone, but in the present invention, energy beam curable compounds (B) that do not constitute urethane polymer chains By blending, the storage elastic modulus of the pressure-sensitive adhesive layer becomes low, and it becomes easy to secure the embedding property to the bumps.
In the present invention, the photopolymerizable unsaturated bond means an unsaturated bond which reacts by energy ray irradiation, and is usually an ethylenic double bond, preferably carbon-carbon contained in a (meth) acryloyl group. It is a double bond.

The molecular weight of the energy ray curable compound (B) is 35,000 or less. When the molecular weight is more than 35,000, the storage elastic modulus of the pressure-sensitive adhesive layer is less likely to be reduced, and it is difficult to ensure the burying property to bumps. In addition, the compatibility with the urethane resin (A) may be deteriorated. The molecular weight of the energy ray-curable compound (B) is preferably 150 to 35,000, and more preferably 200 to 34,000. In addition, molecular weight is formula weight, when formula weight can be specified, and when formula weight can not be specified, it means a weight average molecular weight.
The compounding amount of the energy ray-curable compound (B) varies depending on the compound to be used, but 100 parts by mass of the urethane resin (A) (that is, a total of 100 parts by mass of the urethane polymer (A ′) and the main agent reactive compound) The same shall apply hereinafter), usually 1 to 120 parts by mass, preferably 2 to 100 parts by mass, and more preferably 4 to 90 parts by mass. By setting the compounding amount of the energy ray-curable compound (B) in such a range, it is easy to obtain a pressure-sensitive adhesive layer in which the followability to the work surface and the suppression of adhesive residue are compatible.

Specific examples of the energy ray-curable compound (B) include compounds having a (meth) acryloyl group. The (meth) acryloyl group (photopolymerizable unsaturated bond) in one molecule of the energy ray curable compound (B) may be monofunctional or more, preferably bifunctional or more, and 2 to 12 functional Is more preferred.
In addition, specific examples of the energy ray-curable compound (B) used in the present invention include at least one selected from (meth) acrylate monomer (B1) and urethane (meth) acrylate (B2). .

The (meth) acrylate monomer (B1) is a compound having a (meth) acryloyl group in the molecule, and the number of (meth) acryloyl groups is preferably two or more and more preferably 3 to 6. In particular, when the urethane resin (A) does not have a photopolymerizable unsaturated bond, the (meth) acryloyl group can be easily reduced so that the adhesive strength of the adhesive tape can be easily reduced after the energy ray irradiation to the adhesive layer. The pressure-sensitive adhesive layer preferably contains a (meth) acrylate monomer (B1) in which the number of tetrafunctional groups is four or more.
Examples of the (meth) acrylate monomer (B1) include polyfunctional (meth) acrylic acid esters in which all the hydroxyl groups of the polyhydric alcohol form a complete ester in which an ester is formed with (meth) acrylic acid. Here, as for carbon number of polyhydric alcohol, 4-10 are preferable. The (meth) acrylate monomer (B1) preferably has a molecular weight of 150 to 1,000, and more preferably 200 to 800.
Specific examples of polyfunctional (meth) acrylic acid esters include trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butylene glycol di ( Examples thereof include meta) acrylate and 1,6-hexanediol di (meth) acrylate. Among these, pentaerythritol tetra (meth) acrylate is preferred.
The (meth) acrylate monomer (B1) can specify the structure, and the molecular weight means the formula weight.

The (meth) acrylate monomer (B1) is preferable because it is possible to prevent the adhesive residue and appropriately reduce the adhesive strength by energy ray curing even with a small blending amount.
Further, specifically, the compounding amount of the (meth) acrylate monomer (B1) is preferably 1 to 20 parts by mass, and more preferably 2 to 15 parts by mass with respect to 100 parts by mass of the urethane resin (A). More preferably, it is 3 to 10 parts by mass. With such a compounding amount of the energy ray-curable compound (B), the adhesive residue of the pressure-sensitive adhesive layer can be appropriately prevented, and the adhesion of the pressure-sensitive adhesive layer can be appropriately reduced by energy ray irradiation. It is possible.

Urethane (meth) acrylate (B2) is a polymer which has a urethane bond and has a (meth) acryloyl group at the terminal. The urethane (meth) acrylate (B2) is obtained by reacting a polyol compound with a polyisocyanate compound to form a terminal isocyanate urethane polymer, and reacting a terminal functional group with a compound having a (meth) acryloyl group. A compound etc. are mentioned. Such urethane (meth) acrylate (B2) has energy ray curability by the action of the (meth) acryloyl group.
The polyol compound, the polyisocyanate compound, and the compound having a (meth) acryloyl group, which are used to obtain the urethane (meth) acrylate (B2), may be added to the urethane (meth) acrylate (X) of the intermediate layer described above. The compound is appropriately selected from the polyol compound, the polyisocyanate compound, and the compound having a (meth) acryloyl group to be used, and the specific description thereof is omitted.

The urethane (meth) acrylate (B2) has a (meth) acryloyl group, and the (meth) acryloyl group in one molecule thereof is preferably bifunctional or more, more preferably 2 to 12 functional, still more preferably It is 2-10 functional. As described above, the multifunctionality makes it easy to lower the adhesion by energy ray curing.
The molecular weight of the urethane (meth) acrylate (B2) is 35000 or less, preferably 2000 to 35000, and more preferably 5000 to 34000. In addition, the molecular weight of urethane (meth) acrylate (B2) means a weight average molecular weight. By setting the molecular weight of the urethane (meth) acrylate in such a range, the storage elastic modulus of the pressure-sensitive adhesive layer is reduced, and the followability to the unevenness of the work surface can be easily secured. In addition, the movement of the urethane (meth) acrylate (B2) in the pressure-sensitive adhesive layer is suppressed, and the stability with time of the pressure-sensitive adhesive tape is improved.

  When the energy ray curable compound (B) is a urethane (meth) acrylate (B2), the amount of the urethane (meth) acrylate (B2) is 30 to 120 with respect to 100 parts by mass of the urethane resin (A) A mass part is preferable, 40-100 mass parts is preferable, and 50-90 mass parts is more preferable. With such a blending amount of urethane (meth) acrylate (B2), the adhesion performance of the pressure-sensitive adhesive layer is favorably maintained, and the embeddability can be easily secured. In addition, the adhesive strength is sufficiently reduced by energy ray curing, and furthermore, the adhesive residue can be easily reduced.

(Crosslinking agent (C))
The pressure-sensitive adhesive composition of the present invention preferably further contains a crosslinking agent (C). The crosslinking agent (C) reacts with the urethane polymer (A ′) to crosslink the urethane polymer (A ′). The pressure-sensitive adhesive composition containing the crosslinking agent (C) can easily form a pressure-sensitive adhesive layer having a high crosslinking density and a high mechanical strength. Moreover, it becomes easy to prevent the adhesive residue etc. at the time of peeling an adhesive tape.
As a crosslinking agent (C), when a urethane polymer (A ') has a hydroxyl group, the crosslinking agent which has 2 or more of isocyanate groups is preferable so that it can react with the hydroxyl group. When the pressure-sensitive adhesive composition contains a crosslinking agent, it is usually crosslinked by being applied and then heated.

  Also, conversely, the urethane polymer (A ') may have an isocyanate group, and the crosslinking agent (C) may have a hydroxyl group. The urethane polymer (A ') generally has a hydroxyl group or an isocyanate group in view of its production method, and thus the urethane polymer (A') and the crosslinker (C) are formed by urethane bonds. It is preferred that they be linked.

As a crosslinking agent (C) which can be used by this invention, it is preferable to use the crosslinking agent (C1) containing a photopolymerizable unsaturated bond.
The crosslinker (C1) containing a photopolymerizable unsaturated bond is preferably a compound having two or more isocyanate groups and a (meth) acryloyl group, and more preferably a urethane having at least two isocyanate groups. (Meth) acrylate is used.
The weight average molecular weight of the urethane (meth) acrylate is preferably 500 to 2,000, and more preferably 700 to 1,000. When one molecule of the crosslinking agent (C1) has two or more photopolymerizable unsaturated bonds, the photopolymerizable unsaturated bonds in the same molecule of the crosslinking agent (C1) are polymerized with each other. It tends to be easy. Therefore, the reaction between the photopolymerizable unsaturated bond possessed by the crosslinking agent (C1) and the photopolymerizable unsaturated bond possessed by other molecules is unlikely to occur, and the adhesion of the adhesive tape is lowered by the energy ray irradiation to the adhesive layer. May be less effective. Therefore, preferred as the crosslinking agent (C1) is one having one photopolymerizable unsaturated bond in one molecule. Moreover, as a urethane (meth) acrylate used as a crosslinking agent (C1), "EBECRYL 4150" by Daicel Ornex company is mentioned, for example.
In the present embodiment, by using the crosslinking agent (C1) having a photopolymerizable unsaturated bond, the urethane resin (A) has a photopolymerizable unsaturated bond in the pressure-sensitive adhesive layer.

  As a crosslinking agent containing a hydroxyl group and a photopolymerizable unsaturated bond, the acrylic polymer which has a hydroxyl group and a (meth) acryloyl group in a side chain is mentioned, for example. In this case, the urethane resin (A) crosslinked by the crosslinking agent (C1) becomes a so-called acrylic urethane resin, but the urethane resin (A) of the present invention also includes such an acrylic urethane resin It shall be.

  5-60 mass parts is preferable with respect to 100 mass parts of urethane resin (A), and, as for the compounding quantity of the crosslinking agent (C1) containing a photopolymerizable unsaturated bond, 10-50 mass parts is more preferable, and 15 -45 mass parts are further more preferable. By making a crosslinking agent (C1) into such a compounding quantity, while making the crosslinking density of an adhesive layer favorable, introduce | transducing a photopolymerizable unsaturated bond of a suitable amount into urethane type resin (A). It is possible.

  Moreover, the adhesive composition may contain the crosslinking agent (C2) which does not contain a photopolymerizable unsaturated bond as a crosslinking agent (C). As a crosslinking agent (C2), when a urethane polymer (A ') has a hydroxyl group, it can be used selecting it suitably from the polyisocyanate compound used in order to synthesize | combine the urethane polymer (A') listed above It is. Moreover, when polymer (A ') before bridge | crosslinking has an isocyanate group, a well-known polyol can be used as a crosslinking agent (C2). The pressure-sensitive adhesive composition can sufficiently increase the crosslinking density of the pressure-sensitive adhesive layer by containing the crosslinking agent (C2).

  The crosslinking agent (C) may be a crosslinking agent (C1) all having a photopolymerizable unsaturated bond, or all may be a crosslinking agent (C2) not having a photopolymerizable unsaturated bond It is preferable to contain the crosslinking agent (C1) which has a photopolymerizable unsaturated bond, and it is more preferable to contain both a crosslinking agent (C1) and a crosslinking agent (C2).

  0.2-15 mass parts is preferable with respect to 100 mass parts of urethane resin (A), and, as for the compounding quantity of the crosslinking agent (C2) which does not contain a photopolymerizable unsaturated bond, 0.5-10 mass parts More preferable. Further, as described above, when used in combination with the crosslinking agent (C1), the blending amount of the crosslinking agent (C2) not containing a photopolymerizable unsaturated bond may be relatively small, and the urethane resin (A) 0.2-5 mass parts is preferable with respect to 100 mass parts, and 0.5-2 mass parts is more preferable.

(Compound (D))
When the pressure-sensitive adhesive composition contains a crosslinking agent (C), it may further contain a compound (D) having a photopolymerizable unsaturated bond and a reactive functional group capable of reacting with the crosslinking agent (C). preferable. The compound (D) having a reactive functional group is one that reacts with the crosslinking agent (C) when the urethane polymer (A ′) reacts with the crosslinking agent (C) to form a urethane polymer chain.
When the pressure-sensitive adhesive composition contains the compound (D), a photopolymerizable unsaturated bond is introduced into the urethane resin (A) by the compound (D). Therefore, when the pressure-sensitive adhesive layer is cured by energy rays, the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer can be easily reduced, and the adhesive residue can be further easily prevented. In addition, there is also an effect that the performance of the pressure-sensitive adhesive tape is easily stabilized with time.

As a reactive functional group contained in a compound (D), an isocyanate group and a hydroxyl group are mentioned. Moreover, as a compound (D), the (meth) acrylate monomer which has a hydroxyl group and a (meth) acryloyl group is mentioned. The number of (meth) acryloyl groups (i.e., photopolymerizable unsaturated bonds) in one molecule of the compound (D) is preferably bifunctional or more, more preferably 2 to 5 functional in one molecule. .
The (meth) acrylate monomer used as the component (D) preferably has a molecular weight of 150 to 3,000, more preferably 200 to 2,000.
Examples of the (meth) acrylate monomer used as the component (D) include polyhydric alcohols and polyfunctional (meth) acrylic esters which are partial esters of (meth) acrylic acid. Here, as for carbon number of polyhydric alcohol, 4-10 are preferable. Specific examples of the compound include pentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate and the like, and among them, pentaerythritol tri (meth) acrylate Is preferred.

  The compounding amount of the compound (D) is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and still more preferably 3 to 15 parts by mass with respect to 100 parts by mass of the urethane resin (A) . By blending the compound (D) in such a range, the adhesive strength can be easily reduced by curing of the energy ray without adversely affecting the adhesive performance of the adhesive layer, and the adhesive residue can be easily prevented. In addition, when the energy ray curable compound (B) contains a (meth) acrylate monomer (B1), it is preferable that the compound (D) is generally used. Thus, when the compound (D) and the (meth) acrylate monomer (B1) are used in combination, the effects of the present invention are more easily exhibited.

(Energy ray polymerization initiator (E))
The pressure-sensitive adhesive composition preferably further contains an energy ray polymerization initiator (E). The pressure-sensitive adhesive layer can be easily cured by irradiation with energy rays by containing the energy ray polymerization initiator (E). The energy ray polymerization initiator (E) can be appropriately selected and used from the photopolymerization initiators that can be used for the intermediate layer resin composition listed above.
The compounding amount of the energy ray polymerization initiator (E) is a urethane polymer (A ') having a photopolymerizable unsaturated bond, a crosslinking agent (C1), an energy ray curable compound (B), a compound (D) Preferably it is 0.05-25 mass parts with respect to a total of 100 mass parts of compounds which have a photopolymerizable unsaturated bond, etc., More preferably, it is 0.1-20 mass parts, More preferably, it is 0.3-15 mass It is a department.

The pressure-sensitive adhesive composition may contain other additives conventionally used in urethane-based pressure-sensitive adhesives, and may be a filler such as calcium carbonate or titanium oxide, a colorant, an antioxidant, an antifoamer, You may contain the light stabilizer etc.
The thickness of the pressure-sensitive adhesive layer can be suitably adjusted according to the surface condition of the adherend surface to which the pressure-sensitive adhesive tape is attached, such as the bump height of the wafer surface, preferably 2 to 150 μm, more preferably 5 to 5 μm. It is 100 μm, more preferably 8 to 50 μm.

<Peeling material>
As the release material provided on the pressure-sensitive adhesive layer and the release material used in the process of the manufacturing method described later, a release sheet subjected to single-sided release treatment, a release sheet subjected to double-sided release treatment, etc. are used What apply | coated the release agent on the base material of, etc. are mentioned.
Examples of the substrate for release material include polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin, and plastic films such as polyolefin resin film such as polypropylene resin and polyethylene resin.
Examples of release agents include silicone resins, olefin resins, isoprene resins, rubber elastomers such as butadiene resins, long chain alkyl resins, alkyd resins, fluorine resins, and the like.
The thickness of the release material is not particularly limited, but is preferably 5 to 200 μm, more preferably 10 to 120 μm.

[Production method of adhesive tape]
The method for producing the pressure-sensitive adhesive tape of the present invention is not particularly limited, and can be produced by a known method.
The intermediate layer may be formed by, for example, directly applying a solution of the resin composition for an intermediate layer to one surface of the substrate to form a coated film, and then drying and curing as necessary. it can. The intermediate layer is formed by applying a solution of the resin composition for an intermediate layer on the release-treated surface of the release material to form a coated film, and then drying as necessary, and performing a semi-hardening treatment on the release material. A semi-cured layer may be formed, the semi-cured layer may be bonded to a substrate, and the semi-cured layer may be completely cured. At this time, the release agent may be appropriately removed before or after the semi-cured layer is completely cured. In addition, it is preferable to cure | harden an intermediate | middle layer by irradiating an energy ray to a coating film, and to carry out superposition | polymerization hardening. The energy ray is preferably ultraviolet light. When the intermediate layer is formed using an olefin material, the intermediate layer may be formed by extrusion molding or the like.

  The pressure-sensitive adhesive layer is preferably formed by applying the pressure-sensitive adhesive composition, heating the pressure-sensitive adhesive composition to crosslink it, and optionally drying it. At this time, the pressure-sensitive adhesive composition may be applied directly on the intermediate layer or substrate, or applied to the release-treated surface of the release material to form an adhesive layer, and then, on the intermediate layer or substrate The pressure-sensitive adhesive layer may be pasted to one another. The release material disposed on the pressure-sensitive adhesive layer may be released if necessary.

When forming the intermediate layer and the pressure-sensitive adhesive layer, an organic solvent is further added to the resin composition or pressure-sensitive adhesive composition for intermediate layer to form a dilution liquid of the resin composition or pressure-sensitive adhesive composition for intermediate layer. Good. Examples of the organic solvent to be used include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, isopropanol and the like.
In addition, these organic solvents may use the organic solvent used at the time of the synthesis | combination of each component contained in the resin composition for intermediate | middle layers, or an adhesive composition as it is, and one or more types of organic solvents other than that may be used. May be added.
The resin composition or pressure-sensitive adhesive composition for the intermediate layer can be applied by a known application method. Examples of the coating method include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating.

[How to use adhesive tape]
The pressure-sensitive adhesive tape of the present invention is used to stick to various types of workpieces and to process the workpieces, and it is preferable to use the pressure-sensitive adhesive tape to be applied to a workpiece surface having asperities or protrusions.
Moreover, it is more preferable to stick on the semiconductor wafer surface, especially the wafer surface in which the bump was formed, and to use as an adhesive tape for semiconductor wafer surface protection. Further, it is more preferable to use the adhesive tape as a bag grind tape which is attached to the surface of a semiconductor wafer and protects the circuit formed on the surface of the wafer at the time of back grinding of the wafer thereafter. When the pressure-sensitive adhesive tape of the present invention has an intermediate layer, the burying property is good even if there is a difference in height due to bumps or the like on the wafer surface, so that the protection performance of the wafer surface is good. In this case, the temperature of the pressure-sensitive adhesive tape when the pressure-sensitive adhesive tape is attached to the surface of the semiconductor wafer is, for example, about 40 to 80 ° C., preferably 50 to 70 ° C.

In the present invention, the pressure-sensitive adhesive layer is an energy ray-curable type, and the pressure-sensitive adhesive tape attached to the surface of a work such as a semiconductor wafer is peeled off from the surface of the work after being irradiated with energy rays and energy-hardened. is there. Therefore, the pressure-sensitive adhesive tape is peeled off after the adhesive strength is reduced, and thus the peelability becomes good. Further, as described above, when the adhesive tape after curing is peeled off, adhesive residue hardly occurs.
In addition, when using for a semiconductor wafer, an adhesive tape is not limited to a back grind sheet, It is also possible to use for another use. For example, the adhesive tape may be used as a dicing sheet which is attached to the back of the wafer and holds the wafer when dicing the wafer. The wafer in this case may be a wafer having a through electrode or the like, or may be a wafer having a protrusion or unevenness such as a bump formed on the back surface of the wafer.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by these examples.

The measuring method and evaluation method in the present invention are as follows.
[Weight average molecular weight (Mw), number average molecular weight (Mn)]
It measured on condition of the following using the gel permeation chromatograph apparatus (product name "HLC-8220", Tosoh Corp. make), and used the value measured by standard polystyrene conversion.
(Measurement condition)
Column: “TSK guard column HXL-H” “TSK gel GMHXL (× 2)” “TSK gel G2000 HXL” (all manufactured by Tosoh Corporation)
Column temperature: 40 ° C Developing solvent: Tetrahydrofuran Flow rate: 1.0 mL / min

[Loss tangent (tan δ)]
The resin composition for an intermediate layer used in each example and comparative example is coated by a fountain die method on a polyethylene terephthalate film-based release film (manufactured by Lintec Corporation, product name “SP-PET 381031”, thickness 38 μm) A film was formed. Then, ultraviolet rays were irradiated from the coating film side to form a semi-cured layer.
For ultraviolet irradiation, a belt conveyor type ultraviolet irradiation apparatus (manufactured by I-Graphics, product name “ECS-4011GX”) is used as an ultraviolet irradiation apparatus, and as a ultraviolet source, a high-pressure mercury lamp (manufactured by I-Graphics, product name “ H04-L41 ′ ′), under the conditions of an illumination intensity of 112 mW / cm ^{2 at} a light wavelength of 365 nm and a light intensity of 177 mJ / cm ² (measured with a UV actinometer “UVPF-A1” manufactured by Eyegraphics) as irradiation conditions went.
On the formed semi-cured layer, a polyethylene terephthalate film-based release film (Lintech Co., Ltd., product name “SP-PET 381031”, thickness 38 μm) is laminated, and UV irradiation (using the above-mentioned UV irradiation device and UV source) As irradiation conditions, an illuminance of 271 mW / cm ² and a light amount of 1,200 mJ / cm ² ) were applied and completely cured to form an intermediate layer with a thickness of 200 μm on which peeling films were attached.
Five intermediate layers formed in this manner were prepared, and the PET release film was peeled, and the peeling surfaces were combined to sequentially laminate, thereby preparing an intermediate layer laminate (thickness: 1,000 μm).
Next, the obtained intermediate layer laminate was punched into a circle having a diameter of 10 mm to obtain a sample for measuring the viscoelasticity. A strain of 1 Hz frequency is applied to the above sample by a viscoelasticity measuring device (product name "ARES" manufactured by TA Instruments), and storage at -50 to 150 ° C at a heating rate of 4 ° C / min. The elastic modulus (G ') was measured to obtain a loss tangent (tan δ) at 50 ° C.

[Breaking stress]
The adhesive layer (200 micrometers in thickness) in which the polyethylene terephthalate type | system | group peeling film (The Lintec Corporation make, product name "SP-PET381031") was stuck on both surfaces was prepared. Here, the pressure-sensitive adhesive layer was formed by changing the thickness to 40 μm on one of the release films in the same manner as in Examples and Comparative Examples, and then the other release film was attached to the pressure-sensitive adhesive layer. Five sheets of the pressure-sensitive adhesive layer sandwiched by such release films were prepared, and the surfaces of the pressure-sensitive adhesive layers exposed by releasing one of the release films were made to face each other and laminated. By repeating this procedure, a pressure-sensitive adhesive layer having a thickness of 200 μm on which five pressure-sensitive adhesive layers were laminated was obtained. The laminate of the pressure-sensitive adhesive layer sandwiched between the two release films was irradiated with ultraviolet light at an illumination speed of 220 mm / cm and an irradiation speed of 15 mm / sec using a UV irradiation apparatus “RAD-2000 m / 12” manufactured by Lintec Corporation Thereafter, the cured product of the pressure-sensitive adhesive layer was cut out to 15 mm × 150 mm. Then, a label for film tension was attached to the 25 mm portions at both ends, and a strip-shaped sample of 15 mm × 100 mm in a measurement target portion was produced. The breaking stress was measured at a tensile speed of 200 mm / min with Shimadzu Corporation "Autograph AG-IS 500N".

[Adhesive force before energy beam irradiation]
The adhesive tapes of the examples and comparative examples are uniformly cut to a width of 25 mm, temporarily placed on a silicon mirror wafer as an adherend, and a 1 kg roll is reciprocated on the adhesive mirror by one weight. It stuck by applying a load. After pasting, store at 23 ° C and 50% relative humidity for 1 hour, and then use a tensile tester (Orientech Co., Ltd., product name "Tensilon") at a peeling angle of 180 ° and a peeling speed of 300 mm / min. The adhesion was measured when the adhesive tape was peeled off.
[Adhesive force after energy beam irradiation]
The adhesive tapes of the examples and comparative examples are uniformly cut to a width of 25 mm, temporarily placed on a silicon mirror wafer as an adherend, and a 1 kg roll is reciprocated on the adhesive mirror by one weight. It stuck by applying a load. After pasting, store at 23 ° C under 50% relative humidity environment for 1 hour, UV light from the adhesive tape side as UV light irradiation device "RAD-2000m / 12" made by Lintec Co., Ltd. with illuminance of 220mW / cm and irradiation speed of 15mm / s. And leave it in a 50% relative humidity environment for 5 minutes at 23 ° C., using a tensile tester (Orientech Inc., product name “Tensilon”), peeling angle 180 °, peeling speed 300 mm / The adhesion was measured when the adhesive tape was peeled off in minutes.

[Embedding evaluation]
Wafer with 250 μm bump height, 500 μm pitch, 300 μm diameter spherical bump in plan view (Waltz's 8-inch wafer, bump specification Sn / Ag / Cu = 96.5 / 3 / 0.5 mass%, wafer surface the material pressure-sensitive adhesive tapes produced in examples and Comparative examples SiO _2), was attached with Lintec Corp. laminator "RAD-3510F / 12". In addition, when sticking, the lamination table and the lamination roll of an apparatus were set to 60 degreeC. After lamination, ultraviolet light was irradiated from the adhesive tape side at an illuminance of 220 mW / cm and an irradiation speed of 15 mm / sec using a UV irradiation apparatus “RAD-2000 m / 12” manufactured by Lintec Corporation. Using the digital microscope (product name "VHX-1000" manufactured by Keyence Co., Ltd.), the evaluation wafer to which the adhesive tape thus obtained is attached is measured for the diameter of the circular gap formed around the bumps from the substrate side. The embeddability was calculated by the following equation.
Embedding property = diameter of air gap / diameter of bump × 100 [%]
The calculated embeddability was evaluated on the basis of the following evaluation criteria as the best one having an appropriate gap of 110% or more and less than 130%.
A: Embedding property = 110% or more and less than 130% B: Embedding property = 130% or more and less than 140% C: Embedding property = less than 110% or 140% or more

[Evaluation of adhesive residue on bumps]
An evaluation wafer with an adhesive tape attached, prepared in the same manner as the above-mentioned embedment evaluation test, is applied to a tensile tester (Orientech Co., Ltd., product name "Tensilon") under an environment of 23 ° C and a relative humidity of 50%. The adhesive tape was peeled off at a tensile speed of 120 mm / min. After peeling, the bump portion of the wafer was observed with an electron microscope “VE-9800” manufactured by Keyence Corporation to confirm the presence or absence of adhesive residue.

[Preparation of a substrate with an intermediate layer]
40 parts by mass of monofunctional urethane acrylate, 45 parts by mass of isobonyl acrylate (IBXA), 15 parts by mass of hydroxypropyl acrylate (HPA), pentaerythritol tetrakis (3-mercaptobutyrate) (Showa Denko Co., Ltd., product name "Kalens MTPE1") , A secondary quaternary functional thiol-containing compound, solid content concentration 100 parts by mass%) 3.5 parts by mass, crosslinking agent 1.8 parts by mass, and 2-hydroxy-2-methyl-1- as a photopolymerization initiator 1.0 part by mass of phenyl-propan-1-one (manufactured by BASF, product name “Darocure 1173, solid content concentration 100 parts by mass) was blended to prepare a resin composition for an intermediate layer. The resin composition for an intermediate layer was coated on a polyethylene terephthalate film release film (manufactured by Lintec Corporation, product name “SP-PET 381031”, thickness 38 μm) by a fountain die method to form a coating film.
Then, ultraviolet rays were irradiated from the coating film side to form a semi-cured layer. For ultraviolet irradiation, a belt conveyor type ultraviolet irradiation device (manufactured by I-Graphics, product name “ECS-401GGX”) is used as an ultraviolet irradiation device, and a high-pressure mercury lamp (manufactured by I-Graphics, product name “H04” is used as an ultraviolet light source. -L41 ′ ′), and was performed under the conditions of an illuminance of 112 mW / cm ^{2 at} a light wavelength of 365 nm and a light quantity of 177 mJ / cm ² (measured by product name “UVPF-A1”) as irradiation conditions. .
A base material made of polyethylene terephthalate (PET) film (product name "Cosmo Shine A4100", product name "Cosmo Shine A4100", thickness 50 μm) is laminated on the formed semi-cured layer, and UV irradiation is further conducted from the PET film side (above the ultraviolet irradiation apparatus, using an ultraviolet source, as the irradiation condition, the illuminance 271mW / cm ^2, performs light amount 1200 mJ / cm ^2), and is completely cured, form an intermediate layer with a thickness of 300μm on a PET film base material To obtain a substrate with an intermediate layer.
The loss tangent (tan δ) of the intermediate layer at 50 ° C. measured at a frequency of 1 Hz was 1.92.
In each of the following Examples and Comparative Examples, each part by mass is the one that is diluted with the diluent and is indicated in terms of solid content.

Example 1
A polyurethane polyol having a urethane skeleton and having a plurality of hydroxyl groups (product name "SH-101", weight average molecular weight: 100,000) having a plurality of hydroxyl groups is prepared as the urethane polymer (A '), and this urethane polymer is prepared. (A ′) 32 parts by mass of urethane acrylate having a plurality of isocyanate groups as a crosslinking agent (C1) (made by Daicel Ornex, product name “EBECRYL 4150”, weight average molecular weight: 1,040), energy ray Mixture of pentaerythritol tetraacrylate (formula weight: 352) as a curable compound (B) and pentaerythritol triacrylate (formula weight: 298) as a compound (D) (mass ratio ( B : D) = 40: 60) (Product name “A-TMM-3LM-N” manufactured by Shin-Nakamura Chemical Co., Ltd.) 17 parts by mass, 5 parts by mass of 2,2-dimethoxy-1,2-diphenylethane-1-one (manufactured by BASF, product name “Irgacure 651”) as an energy ray polymerization initiator (E), a crosslinking agent (C2) 1 part by mass of a polyisocyanate compound ("T-501B" manufactured by Toyo Chem Co., Ltd.) was added, stirring was performed for 10 minutes, and diluted with toluene to prepare a pressure-sensitive adhesive composition having a solid content concentration of 40% by mass.
Then, the prepared pressure-sensitive adhesive composition is applied to a polyethylene terephthalate-based release film (manufactured by Lintec Co., Ltd., product name “SP-PET 381031”, thickness 38 μm), heated at 100 ° C. for 2 minutes, and dried. A 10 μm thick adhesive layer was formed on the
Thereafter, the peelable film on the intermediate layer-provided base material previously prepared is removed, and the pressure-sensitive adhesive layer on the peelable film is attached to the exposed intermediate layer, and then the unnecessary portion of the end in the width direction is cut and removed Thus, a pressure-sensitive adhesive tape in which a substrate, an intermediate layer, a pressure-sensitive adhesive layer, and a release film were provided in this order was obtained. The evaluation results of this adhesive tape are shown in Table 1.

Example 2
In the same manner as in Example 1, except that the urethane polymer (A ') was changed to a product name "SP-205" (weight average molecular weight: 98,000) manufactured by Toyo Chem Co., Ltd. and the pressure-sensitive adhesive composition was prepared. The adhesive tape was made.

[Example 3]
17 parts by mass of “A-TMM-3LM-N”, urethane acrylate as an energy ray curable compound (B) (Keigami Kogyo Co., Ltd., product name “UN-6200”, bifunctional, weight average molecular weight 6, 270 A pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition was prepared by changing it to 100 parts by mass.

Example 4
A pressure-sensitive adhesive tape was produced in the same manner as in Example 3, except that the urethane polymer (A ′) was changed to a product name “SP-205” manufactured by Toyo Chem Co., Ltd. and the pressure-sensitive adhesive composition was adjusted.

[Example 5]
Example 1 and Example 1 except that 17 parts by mass of “A-TMM-3LM-N” was changed to 100 parts by mass of urethane acrylate (6-functional, weight average molecular weight 33,000) as the energy ray curable compound (B) The adhesive tape was produced in the same procedure.

Comparative Example 1
To an acrylic copolymer obtained by polymerizing 94 parts by mass of 2-ethylhexyl acrylate and 6 parts by mass of 2-hydroxyethyl acrylate, 2-isocyanate ethyl methacrylate (manufactured by Showa Denko K.K., product name "Karenz MOI") is acrylic. A methacryloyl group-added acrylic copolymer (weight average molecular weight: 900,000, solid content: 35% by mass) was added such that the addition rate to hydroxyl groups in the copolymer was 50% based on the number of moles. To 100 parts by mass of this copolymer, 3 parts by mass of 1-hydroxylcyclohexyl phenyl ketone (manufactured by BASF, product name “Irgacure 184”) as a photopolymerization initiator, and a polyisocyanate compound (manufactured by Toyo Chem Co., Ltd., product name) 0.8 parts by mass of “BHS-8515”) was added, and stirring was performed for 30 minutes to prepare an acrylic pressure-sensitive adhesive composition. The obtained acrylic pressure-sensitive adhesive composition was applied to a polyethylene terephthalate-based release film (manufactured by Lintec Co., Ltd., product name “SP-PET 381031”, thickness 38 μm) and dried to form a 10 μm-thick pressure-sensitive adhesive layer .
After removing the release film on the intermediate layer-provided base material prepared above and laminating the exposed intermediate layer and the pressure-sensitive adhesive layer on the release film, cut and remove unnecessary portions of the end in the width direction A substrate, an intermediate layer, a pressure-sensitive adhesive layer, and a release film were provided in this order to obtain a pressure-sensitive adhesive tape. The evaluation results of this adhesive tape are shown in Table 1.

Comparative Example 2
In an acrylic copolymer obtained by polymerizing 90 parts by mass of 2-ethylhexyl acrylate and 10 parts by mass of 4-hydroxybutyl acrylate, 2-isocyanate ethyl methacrylate (manufactured by Showa Denko K.K., product name "Kalenz MOI") is used as an acrylic copolymer. A methacryloyl group-added acrylic copolymer (weight-average molecular weight: 1,000,000, solid content: 25% by mass) was obtained by addition such that the addition rate to hydroxyl groups in the polymer was 65% based on the number of moles. . To 100 parts by mass of this copolymer, 3 parts by mass of 1-hydroxylcyclohexyl phenyl ketone (manufactured by BASF, product name “Irgacure 184”) as a photopolymerization initiator, and a polyisocyanate compound (manufactured by Toyo Chem Co., Ltd., product name) 1.1 parts by mass of “BHS-8515”) was added, and stirring was performed for 30 minutes to prepare an acrylic pressure-sensitive adhesive composition. A pressure-sensitive adhesive tape was produced in the same manner as in Comparative Example 1 except for the above.

Comparative Example 3
To an acrylic copolymer obtained by polymerizing 90 parts by mass of 2-ethylhexyl acrylate and 10 parts by mass of 4-hydroxybutyl acrylate, acrylic of 2-isocyanatoethyl methacrylate (product name "Karenz MOI" manufactured by Showa Denko KK) is used. A methacryloyl group-added acrylic copolymer (weight average molecular weight: 1,000,000, solid content: 25% by mass) is obtained by adding so that the addition rate to hydroxyl groups in the copolymer is 75% based on the number of moles. The
In 100 parts by mass of this copolymer, 5 parts by mass of 1-hydroxyl cyclohexyl phenyl ketone (manufactured by BASF, product name “Irgacure 184”) as a photopolymerization initiator, and a polyisocyanate compound as a crosslinking agent (trade name: manufactured by Toyo Chem Co., Ltd.) 1.2 parts by mass of product name "BHS-8515") was added, and stirring was performed for 30 minutes to prepare an acrylic pressure-sensitive adhesive composition. A pressure-sensitive adhesive tape was produced in the same manner as in Comparative Example 1 except for the above.

Comparative Example 4
The adhesive tape was produced in the procedure similar to Example 1 except not adding "A-TMM-3LM-N."

In Examples 1 to 5 above, the pressure-sensitive adhesive composition is urethane-based, and the non-reacting energy ray-curable compound (B) is contained in the urethane-based resin (A), whereby the burying property of the bumps ( While the followability of the pressure-sensitive adhesive layer to the surface shape of the work became good, the breaking stress became high, and the adhesive residue at the time of peeling could be prevented. Furthermore, the adhesion before energy ray curing was enhanced, and the adhesion after curing was sufficiently low, so that the releasability and adhesion were excellent.
On the other hand, in Comparative Examples 1 to 3, since the pressure-sensitive adhesive composition was acrylic, the breaking stress was low, and the adhesive residue could not be prevented. Moreover, in Comparative Example 4, although the urethane type was used, since the energy ray curable compound (B) was not contained, the flexibility of the pressure-sensitive adhesive layer was inferior, and the embeddability was not sufficient.

Claims (19)

A substrate, and an adhesive layer provided on one side of the substrate,
The energy ray-curable compound wherein the pressure-sensitive adhesive layer is non-reactive with the urethane resin (A) and the urethane resin (A) and has a photopolymerizable unsaturated bond and a molecular weight of 35,000 or less (B) and saw including a workpiece, is used by attaching to the surface is uneven, for adhesive tape workpiece machining.   The pressure-sensitive adhesive tape for work processing according to claim 1, wherein the energy ray-curable compound (B) is at least one selected from a (meth) acrylate monomer (B1) and a urethane (meth) acrylate (B2).   The energy beam curable compound (B) contains at least a (meth) acrylate monomer (B1), and the (meth) acrylate monomer (B1) is a complete ester of a polyhydric alcohol and (meth) acrylic acid The pressure-sensitive adhesive tape for processing a work according to claim 2, which is a polyfunctional (meth) acrylic acid ester.   The pressure-sensitive adhesive tape for work processing according to any one of claims 1 to 3, wherein the energy ray-curable compound (B) has two or more (meth) acryloyl groups in one molecule.   The pressure-sensitive adhesive tape for processing a work according to any one of claims 1 to 4, wherein the urethane resin (A) has a photopolymerizable unsaturated bond.   The compounding quantity of the said energy beam curable compound (B) is 1-4.7 mass parts with respect to 100 mass parts of said urethane resins (A), The any one of Claims 1-5 Adhesive tape for work processing. The pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing at least a urethane polymer (A ′), the energy ray-curable compound (B), and a crosslinking agent (C),
The pressure-sensitive adhesive tape for work processing according to any one of claims 1 to 6 , wherein the urethane resin (A) is obtained by crosslinking a urethane polymer (A ') with the crosslinking agent (C). The adhesive tape for workpiece processing according to claim 7 , wherein the crosslinking agent (C) contains a crosslinking agent (C1) containing a photopolymerizable unsaturated bond. The adhesive tape for work processing according to claim 7 or 8 , wherein the urethane polymer (A ') and the crosslinking agent (C) are bonded by a urethane bond. The adhesive tape for workpiece | work processing of any one of Claims 7-9 whose compounding quantity of the said urethane polymer (A ') in the said adhesive composition is 30-85 mass%. The pressure-sensitive adhesive composition according to any one of claims 7 to 10 , further comprising a compound (D) having a photopolymerizable unsaturated bond and a reactive functional group capable of reacting with the crosslinking agent (C). The adhesive tape for work processing as described in. The pressure-sensitive adhesive tape for processing a work according to claim 11 , wherein the compound (D) is a polyfunctional (meth) acrylic acid ester which is a partial ester of a polyhydric alcohol and (meth) acrylic acid. The pressure-sensitive adhesive tape for processing a work according to any one of claims 1 to 12 , wherein a breaking stress after energy beam irradiation of the pressure-sensitive adhesive layer is 2.5 MPa or more. Wherein between the substrate and the pressure-sensitive adhesive layer, the work processing adhesive tape according to any one of claims 1 to 13 having an intermediate layer. The adhesive tape for workpiece processing according to claim 14 , wherein the thickness of the intermediate layer is 10 to 600 μm. The intermediate layer, the loss tangent at 50 ° C. was measured at a frequency 1Hz is 1.0 or more, the pressure-sensitive adhesive tape for machining a workpiece according to claim 14 or 15. The adhesive tape for workpiece | work processing of any one of Claims 1-16 in which the said adhesive layer does not contain an acrylic adhesive. The pressure-sensitive adhesive tape for processing a work according to any one of claims 1 to 17 , wherein the adhesive strength after energy beam irradiation is 2000 mN / 25 mm or less. The pressure-sensitive adhesive tape for processing a work according to any one of claims 1 to 18 , which is a pressure-sensitive adhesive tape for protecting the surface of a semiconductor wafer.