JP6200611B1 - Semiconductor wafer processing adhesive tape, semiconductor wafer processing adhesive tape manufacturing method, and semiconductor wafer processing method - Google Patents

Abstract

[PROBLEMS] To provide a semiconductor wafer processing pressure-sensitive adhesive tape having good followability to the surface of a semiconductor wafer having steps and protrusions and capable of being peeled off without damaging the semiconductor wafer or leaving adhesive residue at the time of peeling. And a method for processing a semiconductor wafer. A pressure-sensitive adhesive tape for processing a semiconductor wafer having a pressure-sensitive adhesive layer on at least one surface of a base film, wherein the pressure-sensitive adhesive in the pressure-sensitive adhesive layer comprises at least component (a), component (b) and component. (C) Each of the components (a) is a crosslinking agent, and the component (b) has a reactive functional group that reacts with the crosslinking agent of the component (a). And the component (c) is a compound having an ethylenically unsaturated group and a reactive functional group that reacts with the crosslinking agent of the component (a), and the gel fraction of the pressure-sensitive adhesive is 30. -80% adhesive tape for semiconductor wafer processing, method for producing adhesive tape for semiconductor wafer processing, and semiconductor wafer processing method. [Selection figure] None

Description

  The present invention relates to an adhesive tape for processing a semiconductor wafer, a method for manufacturing an adhesive tape for processing a semiconductor wafer, and a method for processing a semiconductor wafer.

A semiconductor package is manufactured by slicing a high-purity silicon single crystal or the like into a semiconductor wafer, and then forming an integrated circuit on the surface of the semiconductor wafer by ion implantation, etching, or the like. The semiconductor wafer is processed to a desired thickness by grinding or polishing the back surface of the semiconductor wafer on which the integrated circuit is formed. At this time, in order to protect the integrated circuit formed on the surface of the semiconductor wafer, an adhesive tape for protecting the surface of the semiconductor wafer (hereinafter also simply referred to as “surface protective tape”) is used.
The back-ground semiconductor wafer is stored in a semiconductor wafer cassette after the back-side grinding is completed, transported to a dicing process, and processed into semiconductor chips.

Conventionally, the thickness of the semiconductor wafer has been required to be about 200 to 400 μm by back grinding or the like. However, with the recent progress of high-density mounting technology, it is necessary to reduce the size of the semiconductor chip, and accordingly, the semiconductor wafer is becoming thinner. Depending on the type of semiconductor chip, it is necessary to thin the semiconductor wafer to 100 μm or less. On the other hand, in order to increase the number of semiconductor chips that can be manufactured by a single process, the diameter of the original semiconductor wafer tends to be increased. Until now, semiconductor wafers with diameters of 5 inches and 6 inches have been mainstream, but in recent years, processing of semiconductor wafers with diameters of 8 to 12 inches into semiconductor chips has become mainstream, and even semiconductors with an 18 inch diameter. Introduction of wafers is also under consideration.
The trend of increasing the diameter of a semiconductor wafer at the same time as making it thinner is particularly remarkable in the field of flash memory where NAND type and NOR type exist, and in the field of DRAM, which is a volatile memory. For example, it is not uncommon to grind a semiconductor wafer having a diameter of 12 inches to a thickness of 100 μm or less.

  In addition to this, wafers used for flip-chip mounting using electrode-equipped semiconductor wafers that take impact resistance into account with the recent spread of smartphones, mobile phone performance improvements, music player miniaturization, and performance improvements, etc. There is also an increasing demand for thin films. In addition, with respect to the semiconductor wafer with bumps, it is necessary to perform thin film grinding of the semiconductor wafer portion to 100 μm or less. Bumps for flip chip connection have been densified in order to improve transfer speed, and bump height (projection height from the surface of the semiconductor wafer) has been reduced, and accordingly, the distance between bumps. Is getting shorter. In recent years, flip chip connection has also been implemented in DRAMs, so that the thinning of semiconductor wafers has been accelerated.

  Flip chip mounting has been attracting attention as a method for mounting a semiconductor element with a minimum area in response to recent downsizing and higher density of electronic devices. Bumps are formed on the electrodes of the semiconductor element used for the flip chip mounting, and the bumps are electrically joined to the wiring on the circuit board. As the composition of these bumps, solder, copper and gold are mainly used. The solder bumps, copper and gold bumps are formed on the exposed aluminum terminals connected to the internal wiring of the chip by vapor deposition or plating.

  However, bumped semiconductor wafers have large irregularities on the surface, making thin film processing difficult, and if the backside grinding is performed using ordinary adhesive tape, semiconductor wafer cracks may occur or the thickness of the semiconductor wafer It may cause deterioration of accuracy. For this reason, the bumped semiconductor wafer is ground using a specially designed surface protection tape (see, for example, Patent Document 1).

  However, since these surface protective tapes sufficiently absorb the bumps to ensure the grindability, it is very difficult to achieve compatibility with the peelability. The finished thickness of the chip that has been flip-chip mounted so far has a certain thickness of 200 μm or more, and has been able to be peeled off because of its rigidity. However, recently, the thickness of the finished semiconductor wafer has become even thinner and the bump density has increased, which has caused a problem that the surface protection tape cannot be easily peeled off. On the other hand, if the peelability is ensured, the adhesion becomes insufficient, causing intrusion of grinding water and residual glue during back grinding.

  In addition, the bump height of the semiconductor wafer with bumps used in the wafer level package remains high, and bumps with a height of 250 μm or more are also mounted. Wafer level packages do not require chip stacking, so they are not ground as thin as 50 μm or less like memory semiconductor wafers, but they are very easy to break even with thick film grinding because they have high bumps and are 150 μm thick. The following grinding thickness easily causes the problem of semiconductor wafer cracking.

On the other hand, in recent years, various studies have been conducted using a radiation curable pressure-sensitive adhesive having an ethylenically unsaturated group in a polymer. For example, an acrylic copolymer having a functional group-containing monomer unit and a substitution that reacts with this functional group in order to peel it from the semiconductor wafer surface without destroying a fine pattern on the surface of the semiconductor wafer without leaving an adhesive. A radiation curable copolymer obtained by containing a compound containing an ethylenically unsaturated group having a group (see, for example, Patent Documents 1 and 2) is representative.
Further, a urethane acrylate oligomer in which a compound having an ethylenically unsaturated group to be reacted with an acrylic copolymer having a functional group-containing monomer unit is reacted with an aliphatic diisocyanate and an acrylate having one hydroxyl group (for example, Patent Document 3) See also).

JP 2001-203255 A Japanese Patent Laid-Open No. 9-298173 JP 2008-021897 A

  However, in the conventional surface protection tape as shown in Patent Documents 1 to 3, the height of the step and the protrusion becomes higher and the thickness of the semiconductor wafer to be ground and the semiconductor wafer after grinding becomes thinner and thinner. In the situation, not necessarily enough.

  Therefore, the present invention is suitably used for a semiconductor wafer having a step or a protrusion, has good followability to the surface of the semiconductor wafer, and can be peeled off without damaging the semiconductor wafer or leaving adhesive residue at the time of peeling. It is an object of the present invention to provide a method for manufacturing a tape, an adhesive tape for processing a semiconductor wafer, and a method for processing a semiconductor wafer.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors used a base polymer of a specific radiation-curable polymer as an adhesive, and the gel fraction of the adhesive before irradiation is important. Based on this finding, the present invention has been completed.

That is, the said subject of this invention was achieved by the following means.
<1> A semiconductor wafer processing adhesive tape having an adhesive layer on at least one surface of a substrate film,
The pressure-sensitive adhesive of the pressure-sensitive adhesive layer comprises at least each of component (a), component (b) and component (c),
The component (a) is a crosslinking agent, the component (b) is a (meth) acrylic copolymer having a reactive functional group that reacts with the crosslinking agent of the component (a), and the component (c) ) Is a compound having an ethylenically unsaturated group and a reactive functional group that reacts with the crosslinking agent of component (a), and
A pressure-sensitive adhesive tape for processing semiconductor wafers, wherein the pressure-sensitive adhesive has a gel fraction of 30 to 80%.
<2> The total number of ethylenically unsaturated groups of the component (c) is 20 to 90 when the total number of ethylenically unsaturated groups of all the components constituting the pressure-sensitive adhesive is 100. <1> The semiconductor wafer processing adhesive tape according to <1>.
<3> The adhesive tape for semiconductor wafer processing according to <1> or <2>, wherein the compound of component (c) is urethane acrylate.
<4> In addition to the crosslinking agent of component (a), the component (d) has a crosslinking agent having a reactive functional group different from that of the crosslinking agent of component (a) <1> The adhesive tape for semiconductor wafer processing of any one of-<3>.
<5> A method for producing an adhesive tape for processing a semiconductor wafer having an adhesive layer on at least one surface of a substrate film,
The pressure-sensitive adhesive layer is made of a pressure-sensitive adhesive having a gel fraction of 30 to 80%,
The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer contains at least each of the component (a), the component (b) and the component (c),
The component (a) is a crosslinking agent, the component (b) is a (meth) acrylic copolymer having a reactive functional group that reacts with the crosslinking agent of the component (a), and the component (c) ) Is a compound having an ethylenically unsaturated group and a reactive functional group that reacts with the crosslinking agent of component (a),
The manufacturing method of the adhesive tape for semiconductor wafer processing characterized by forming the said adhesive layer on the said base film with the said adhesive composition.
<6> When the total number of ethylenically unsaturated groups of all components having an ethylenically unsaturated group contained in the pressure-sensitive adhesive composition is 100, the total number of ethylenically unsaturated groups of the component (c) Is 20-90, The manufacturing method of the adhesive tape for semiconductor wafer processing as described in <5> characterized by the above-mentioned.
<7> The method for producing an adhesive tape for processing a semiconductor wafer according to <5> or <6>, wherein the compound of the component (c) is urethane acrylate.
<8> In addition to the crosslinking agent of component (a), the component (d) has a crosslinking agent having a reactive functional group different from that of the crosslinking agent of component (a) <5> The manufacturing method of the adhesive tape for semiconductor wafer processing of any one of-<7>.
<9> The semiconductor wafer processing adhesive tape according to any one of the above items <1> to <4> is bonded to a semiconductor wafer surface having a surface irregularity of 10 μm or more, and then irradiated with ultraviolet rays to process the semiconductor wafer. A method for processing a semiconductor wafer, comprising a step of peeling the adhesive tape for use.

According to the present invention, a semiconductor wafer processing pressure-sensitive adhesive tape having good followability to the surface of a semiconductor wafer and capable of being peeled off without being damaged or having adhesive residue at the time of peeling, a method for producing a semiconductor wafer processing pressure-sensitive adhesive tape, and a semiconductor wafer It became possible to provide a processing method.
In particular, in the present invention, the above-described effects of the present invention are effectively exhibited for a semiconductor wafer having steps and protrusions, and further, a semiconductor wafer to be ground or a semiconductor wafer having a thin thickness after grinding.

<< Semiconductor wafer processing adhesive tape >>
The pressure-sensitive adhesive tape for semiconductor wafer processing of the present invention has a pressure-sensitive adhesive layer on at least one surface of a base film, and the pressure-sensitive adhesive of the pressure-sensitive adhesive layer contains at least component (a), component (b) and component ( (meth) acrylic copolymer comprising each of c), wherein the component (a) is a crosslinking agent, and the component (b) has a reactive functional group that reacts with the crosslinking agent of the component (a) And the component (c) is a compound having an ethylenically unsaturated group and a reactive functional group that reacts with the crosslinking agent of the component (a), and the pressure-sensitive adhesive has a gel fraction of 30 to 80%.

<Base film>
The base film is preferably made of a resin film, and known plastics, rubbers and the like can be used. For example, polyolefin resin (polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid Α-olefin homopolymers or copolymers such as methyl copolymers, ethylene-acrylic acid copolymers, ionomers, or mixtures thereof), polyester resins (polyethylene terephthalate, polyethylene naphthalate), polycarbonate resins, polyurethane resins Engineering plastics (polymethyl methacrylate, etc.), synthetic rubbers (styrene-ethylene-butene or pentene copolymers), thermoplastic elastomers (polyamide-polyol copolymers, etc.), and mixtures thereof Thing, and the like. Moreover, you may use what made these two or more layers.
In the present invention, the base film is preferably a polyolefin resin, and more preferably an ethylene-vinyl acetate copolymer film.

The thickness of the base film is 50 to 500 μm if it is a base material having flexibility such as polyethylene, and has rigidity such as polyester, from the viewpoints of high elongation properties, peelability of the surface protection tape, and cutability in the bonding machine. If it is a base material, 10-100 micrometers is suitable.
In addition, using a resin that can be softened by heating at the time of laminating a surface protection tape as a flexible resin, and using a laminated film in which a rigid resin is laminated as a base material also ensures followability and suppresses warpage of the wafer. It is preferable from the viewpoint. In the case of such a laminated film, the total thickness is preferably 100 to 600 μm.

<Adhesive layer (adhesive)>
(Base polymer)
In the present invention, the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer is a radiation curable pressure-sensitive adhesive.
The base polymer of the radiation curable pressure-sensitive adhesive is, as a main component, 1) a polymer having a crosslinked structure and having an ethylenically unsaturated group, or 2) a polymer having an ethylenically unsaturated group in the side chain.
In the present invention, among these, a polymer having an ethylenically unsaturated group in the crosslinked structure of 1) is used.
Specifically, the polymer having an ethylenically unsaturated group in the cross-linked structure of 1) includes a component (a), a component (b), and a component (c), and the component (a) is a cross-linking agent. The component (b) is a (meth) acrylic copolymer having a reactive functional group that reacts with the crosslinking agent of the component (a), and the component (c) is an ethylenically unsaturated group It is a compound having a reactive functional group that reacts with the crosslinking agent of component (a).
The above polymers 1) and 2) will be collectively referred to as radiation-sensitive polymers hereinafter.

  Here, the polymer having an ethylenically unsaturated group in the side chain is a polymer in which an ethylenically unsaturated group (ethylenic carbon-carbon double bond) is bonded to the polymer chain directly or via a linking group. is there. A polymer having an ethylenically unsaturated group in a cross-linked structure is a polymer in which polymer molecules are cross-linked with a cross-linking agent or the like, and an ethylenically unsaturated group is present in a polymer chain or a cross-linked part (part derived from the cross-linking agent). It is a polymer having

Note that the above-mentioned polymer chains are polymer chains themselves, for example, in a repeating unit derived from methacrylic acid methyl _{ester, - [CH 2 -C (CH} 3) (CO 2 CH 3)] - and CH ₃ of CO ₂ CH ₃ is a side chain, and the atomic part constituting the polymer chain is — [carbon atom—carbon atom] —. The linking group is a divalent organic group that connects atoms (carbon atoms in the above) constituting the polymer chain and carbon atoms of the ethylenically unsaturated group. For example, -CO ₂ -L ^1- ( meth) acryloyloxy ^{_{group, -CO 2 -L 1 -O-C}} (= O) -NH-L 2 - (meth) acryloyloxy group.
L ¹ and L ² are a divalent linking group, and are an alkylene group, an arylene group, a divalent heterocyclic group, —O—, —S—, SO ₂ —, —N (Ra) —, — Examples thereof include C (═O) — or a group obtained by combining these. Here, Ra represents a hydrogen atom or a substituent (an alkyl group, an aryl group, a heterocyclic group, an acyl group, an alkoxycarbonyl group, or an alkyl or aryl sulfonyl group).

Further, the main component means that the polymer component 1) or 2) is at least 50% by mass or more, preferably 80% by mass or more (100% by mass or less).
Examples of the polymer other than the polymer component 1) or 2) include known chlorinated polypropylene resins, acrylic resins ((meth) acrylic resins), polyester resins, polyurethane resins, epoxy resins, rubbers used for adhesives. Can be used.

Examples of the ethylenically unsaturated group include a vinyl group, an allyl group, a styryl group, a (meth) acryloyl group, a (meth) acryloyloxy group, and a (meth) acryloylamino group.
In addition, “(meth)” means both a group based on an acrylic acid derivative and a group based on a methacrylic acid derivative, such as a (meth) acryloyl group, a (meth) acryloyloxy group, and a (meth) acryloylamino group. Any one of these may be a mixture thereof. The same applies to other similar terms. For example, a (meth) acryloyloxy group means both an acryloyloxy group and a methacryloyloxy group.

  The ethylenically unsaturated group possessed by the polymer can be polymerized and cured by irradiation with radiation such as ultraviolet rays or electron beams.

Examples of the base polymer of the pressure-sensitive adhesive include (meth) acrylic copolymer, polyester, ethylene or styrene copolymer, and polyurethane.
In this invention, it is a (meth) acrylic copolymer like a component (b).

The polymer having an ethylenically unsaturated group in the crosslinked structure of 1) The polymer having an ethylenically unsaturated group in the crosslinked structure is a polymer having an ethylenically unsaturated group and having a crosslinked structure.
Such a polymer comprises a component (a) of a crosslinker, a component (b) of a (meth) acrylic copolymer having a reactive functional group (α) that reacts with the crosslinker of the component (a), and an ethylenic polymer. Each of the components (c) of the compound having a saturated functional group and a reactive functional group (β) that reacts with the crosslinking agent of the component (a) forms a polymer having a crosslinked structure.
Therefore, the crosslinking agent of component (a) has at least two reactive functional groups (α) and (β) in its molecule.
Here, the reactive functional groups (α) and (β) may be the same or different.

Examples of such reactive functional groups (α) and (β) include a crosslinking agent of component (a), a group that undergoes a nucleophilic attack, a group that undergoes a nucleophilic attack, or a group that undergoes an addition reaction.
As reactive functional groups (α) and (β), for example, hydroxyl groups, amino groups, mercapto groups, carboxy groups, epoxy groups, oxetanyl groups, isocyanate groups (—N═C═O), cyclic acid anhydrides are formed. Group, a halogen atom, an alkoxy or aryloxycarbonyl group, and the like.
Here, when the crosslinkable group possessed by the crosslinker of component (a), that is, the reactive functional group (γ) is a group that undergoes a nucleophilic attack or a group that undergoes an addition reaction, the reactive functional group (α), (Β) is preferably a hydroxyl group, an amino group, a mercapto group, or a carboxy group, more preferably a hydroxyl group or a carboxy group, and even more preferably a hydroxyl group.
Conversely, when the crosslinkable group of the crosslinker of component (a), that is, the reactive functional group (γ) is a group that undergoes nucleophilic attack, the reactive functional group (α), (β) is an epoxy group, Examples thereof include an oxetanyl group, an isocyanate group (—N═C═O), a group forming a cyclic acid anhydride, a halogen atom, an alkoxy or aryloxycarbonyl group.
In addition, when the crosslinkable group which the crosslinking agent of component (a) has, ie, the reactive functional group (γ) is an epoxy group or an oxetanyl group, the reactive functional group (α) or (β) is an epoxy group or an oxetanyl group. It does not matter.
In the present invention, the crosslinkable group of the crosslinker of component (a), that is, the reactive functional group (γ) is preferably a group that undergoes nucleophilic attack or a group that undergoes an addition reaction.

[Component (b)]
The (meth) acrylic copolymer having a reactive functional group (α) that reacts with the crosslinking agent of component (a) is obtained from a monomer having a reactive functional group (α) that reacts with the crosslinking agent of component (a). It is done.

-Monomer whose reactive functional group (α) is a carboxy group-
(Meth) acrylic acid, cinnamic acid, itaconic acid, fumaric acid, etc.

-Monomer whose reactive functional group (α) is a hydroxyl group-
Hydroxyalkyl (meth) acrylate having a hydroxyl group in the alcohol part [for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, trimethylolpropane mono (meth) acrylate, glycol mono (meth) acrylate, diethylene glycol Mono (meth) acrylate], N- (hydroxyalkyl) alkyl (meth) acrylamide of an alkylamine having a hydroxyl group in the amine portion [for example, N-methylol (meth) acrylamide, N, N-bismethylol (meth) acrylamide], Allyl alcohol, etc.

-Monomer whose reactive functional group (α) is an amino group-
Aminoalkyl (meth) acrylate having an amino group in the alcohol part [for example, 2- (alkylamino) ethyl (meth) acrylate, 3- (alkylamino) propyl (meth) acrylate], (meth) acrylamide, etc.

-Monomer whose reactive functional group (α) is a cyclic acid anhydride-
Maleic anhydride, itaconic anhydride, fumaric anhydride, phthalic anhydride, etc.

-Monomer whose reactive functional group (α) is an epoxy group or oxetanyl group-
Glycidyl (meth) acrylate, allyl glycidyl ether, 3-ethyl-3-hydroxymethyloxetane, etc.

-Monomer whose reactive functional group (α) is an isocyanate group-
(Meth) acryloyloxyalkyl isocyanate [for example, 2- (meth) acryloyloxyethyl isocyanate, 2- (meth) acryloyloxypropyl isocyanate], a part of the isocyanate group of the polyvalent isocyanate compound, a hydroxyl group or a carboxy group, and ethylene Urethanized with a compound having an unsaturated group [for example, 2 to 10 functional (meth) acrylic urethane acrylate oligomer], etc.

  The (meth) acrylic copolymer having a reactive functional group (α) that reacts with the crosslinking agent of component (a) reacts with a monomer that has a reactive functional group (α) that reacts with the crosslinking agent of component (a). Copolymerization with monomers having no functional functional group (α) is particularly preferred.

As the monomer having no reactive functional group (α), (meth) acrylic acid ester is preferable, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, Examples include n-hexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, decyl acrylate hexyl acrylate, and the corresponding methacrylates.
Although the (meth) acrylic acid ester may be one type or two or more types, it is preferable to use those having an alcohol part having 5 or less carbon atoms and those having 6 to 12 carbon atoms.

In addition, since a glass transition point (Tg) becomes so low that a monomer with large carbon number of an alcohol part is used, the thing of a desired glass transition point can be obtained. In addition to the glass transition point, it is also preferable to blend a low molecular compound having a carbon-carbon double bond such as vinyl acetate, styrene or acrylonitrile for the purpose of improving compatibility and various performances. The content of is preferably in the range of 5% by mass or less.
The polymer Tg in the present invention is preferably -50 to 20 ° C, more preferably -25 to 10 ° C. By setting the Tg to be high, a high cohesive force of the pressure-sensitive adhesive can be obtained, which is effective for adhesive residue. On the other hand, the followability to the surface uneven wafer is deteriorated, but in the present invention, adjustment is made by adding an oligomer [for example, a compound having component (c) and a compound having an ethylenically unsaturated group that is not incorporated into the crosslinking system]. Is possible.

  The (meth) acrylic copolymer of component (b) may be used alone or in combination of two or more.

[Component (c)]
A compound having an ethylenically unsaturated group and a reactive functional group (β) that reacts with the crosslinking agent of the component (a) includes an ethylenically unsaturated group and a reactive functional group (β) that undergoes nucleophilic attack. A compound having is preferred.
Specifically, the reactive functional group (β) is preferably a hydroxyl group, an amino group, a mercapto group or a carboxy group, more preferably a hydroxyl group, an amino group or a carboxy group, further preferably a hydroxyl group or a carboxy group, and more preferably a hydroxyl group. preferable.
Although one or more reactive functional groups (β) may be present, one is preferred in the present invention.

  2-15 are preferable, as for the number of the ethylenically unsaturated groups in 1 molecule, 2-8 are more preferable, and 3-6 are more preferable.

  A compound having a reactive functional group (β) and having an ethylenically unsaturated group is an ester compound or reactive functional group (β) of a (meth) acryloylated polyhydric alcohol leaving at least one hydroxyl group. ) (Preferably a urethane acrylate oligomer having at least one hydroxyl group) is preferred, and a urethane acrylate oligomer having at least one hydroxyl group is more preferred.

  Examples of ester compounds of polyhydric alcohols that are at least one hydroxyl group and are (meth) acryloylated include, for example, trimethylolpropane di (meth) acrylate, tetramethylolmethane tri (meth) acrylate, and pentaerythritol di (meth). Acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, 1,4-butylene glycol mono (meth) acrylate, 1,6 hexanediol mono (meth) acrylate , Polyethylene glycol mono (meth) acrylate, oligoester (meth) acrylate having one hydroxyl group, and the like.

  The urethane acrylate having at least one reactive functional group (β) is a polyvalent isocyanate compound [for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4. -Xylylene diisocyanate, diphenylmethane 4,4-diisocyanate, etc.) and a polyol compound such as a polyester type or a polyether type are reacted with leaving at least one isocyanate group, and then having the remaining isocyanate group and hydroxy group. Those obtained by reacting (meth) acrylate (for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol (meth) acrylate) are widely applicable.

  The mass average molecular weight of the component (c) compound such as urethane acrylate having at least one reactive functional group (β) is preferably 300 to 100,000, more preferably 500 to 50,000, and 1,000 to 30. 2,000 is more preferable, and 2,000 to 20,000 is particularly preferable.

  The compound of component (c) may be used alone or in combination of two or more.

Component (c) is blended so that the total number of ethylenically unsaturated groups of component (c) is 20 or more when the total number of ethylenically unsaturated groups of all components constituting the adhesive is 100. Preferably, the upper limit of the total number of ethylenically unsaturated groups of component (c) is 90.
The lower limit of the total number of ethylenically unsaturated groups is more preferably 30, and the upper limit of the total number of ethylenically unsaturated groups is more preferably 80.
The lower limit of the total number of ethylenically unsaturated groups is more preferably 40, and the upper limit of the total number of ethylenically unsaturated groups is more preferably 70.

The compounding amount of component (c) depends on the number of ethylenically unsaturated groups in one molecule of component (c), but is preferably 5 to 150 parts by mass with respect to 100 parts by mass of component (b). 10 to 100 parts by mass is more preferable, and 30 to 70 parts by mass is more preferable.
20-200 mass parts is preferable with respect to 100 mass parts of components (b), 30-120 mass parts is more preferable, and, as for the total number of the ethylenically unsaturated group of all the components which comprise an adhesive, 50-100 masses. Part is more preferred.

[Component (a)]
The crosslinking agent of component (a) has at least a crosslinkable group that reacts with component (b) and component (c), that is, a reactive functional group (γ).
The at least two crosslinkable groups, that is, the reactive functional groups (γ) may be the same or different from each other, but are preferably the same in the present invention.
The reactive functional group (γ) is preferably a group that undergoes a nucleophilic attack or a group that undergoes an addition reaction.

  The crosslinkable group that performs the crosslinking reaction of the crosslinking agent, that is, the reactive functional group (γ) is preferably an isocyanate group, an epoxy group, an oxetane group, a halogen atom, an aryloxycarbonyl group, or a group that forms a cyclic acid anhydride. An isocyanate group, an epoxy group, and an oxetane group are more preferable, an isocyanate group and an epoxy group are more preferable, and an isocyanate group is particularly preferable.

  Examples of such crosslinking agents include polyvalent isocyanate compounds, polyvalent epoxy compounds, polyvalent aziridine compounds, chelate compounds and the like.

  There is no restriction | limiting in particular as a polyvalent isocyanate compound, For example, 4,4'- diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4 '-[2,2-bis ( 4-phenoxyphenyl) propane] diisocyanate and other aromatic isocyanates, hexamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane Examples include diisocyanate, lysine diisocyanate, and lysine triisocyanate. Specifically, Coronate L [manufactured by Nippon Polyurethane Industry Co., Ltd., trade name] or the like can be used.

Examples of the polyvalent epoxy compound include epoxy resins, such as ethylene glycol diglycidyl ether, terephthalic acid diglycidyl ester acrylate, and anilines substituted with two glycidyl groups on the N atom.
Examples of anilines include N, N′-tetraglycidyl-m-phenylenediamine.

  Polyvalent aziridine compounds include tris-2,4,6- (1-aziridinyl) -1,3,5-triazine, tris [1- (2-methyl) -aziridinyl] phosphine oxide, hexa [1- (2- Methyl) -aziridinyl] triphosphatriazine and the like. Examples of the chelate compound include ethyl acetoacetate aluminum diisopropylate and aluminum tris (ethyl acetoacetate).

One or two kinds of crosslinking agents may be used in combination.
In the present invention, in addition to the crosslinking agent of component (a), it is preferable to use, as component (d), a crosslinking agent having a reactive functional group different from the crosslinking agent of component (a). For example, by adding the component (d) that does not crosslink with the component (c) but only with the component (b), the crosslinking of the component (b) and the component (c) is adjusted with the component (a), Furthermore, the crosslinking of component (b) can be adjusted with component (d).

  The blending amount of the crosslinking agent is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and further preferably 1 to 6 parts by mass with respect to 100 parts by mass of the starting polymer.

(Photopolymerization initiator)
The radiation curable pressure-sensitive adhesive can contain a photopolymerization initiator as necessary. As long as it reacts with the radiation which permeate | transmits a base material as a photoinitiator, there will be no restriction | limiting in particular, A conventionally well-known thing can be used. For example, benzophenones such as benzophenone, 4,4′-dimethylaminobenzophenone, 4,4′-diethylaminobenzophenone and 4,4′-dichlorobenzophenone, acetophenones such as acetophenone, diethoxyacetophenone and phenyldimethoxyacetylbenzene, 2- Anthraquinones such as ethyl anthraquinone and t-butylanthraquinone, 2-chlorothioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzyl, 2,4,5-triarylimidazole dimer (rophine dimer), acridine compound , Acylphosphine oxides, and the like. These can be used alone or in combination of two or more.

  The addition amount of the photopolymerization initiator is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 7.5 parts by mass, and 0.5 to 5 parts by mass with respect to 100 parts by mass of the radiation curable polymer. Further preferred. When the amount of photopolymerization initiator added is large, radiation curing occurs at multiple points and abruptly, resulting in increased radiation curing shrinkage. Therefore, photopolymerization is performed compared to conventional radiation curing type surface protection adhesive tapes. Reducing the amount of initiator is also useful from the viewpoint of suppressing radiation curing shrinkage.

(Other additives)
If necessary, the radiation curable pressure-sensitive adhesive may contain a tackifier, a tackifier, a surfactant, or other modifiers. Moreover, you may add an inorganic compound filler suitably.
Examples of other additives include silicone acrylates (for example, silicone diacrylate, silicone hexaacrylate) and radiation curing accelerators as additives for preventing wetting or improving slip properties. Moreover, you may contain the amino acrylate and plasticizer as a water-resistant agent as an additive.
In addition, you may contain the surfactant used in the case of superposition | polymerization of a polymer.

In the present invention, when the total number of ethylenically unsaturated groups of all components constituting the pressure-sensitive adhesive is 100, the total number of ethylenically unsaturated groups of the component (c) is preferably 20 to 90. .
This is because the total number of ethylenic carbon-carbon double bonds of all the components having an ethylenically unsaturated group contained in the pressure-sensitive adhesive (pressure-sensitive adhesive composition) is the ethylenic carbon-carbon of the component (c). It also means that the total number of double bonds is 20-90%.
Examples of the ethylenically unsaturated group other than the component (c) include an ethylenically unsaturated group-containing compound that does not have a reactive functional group that crosslinks with the component (a). By having the compound that is not taken into the crosslinking system, the storage elastic modulus of the pressure-sensitive adhesive can be adjusted, and good followability can be obtained for a semiconductor wafer having irregularities on the surface. Moreover, since it is used together with the component (c), it can be crosslinked with the component (b) via the component (a) and the component (c) after the radiation curing.

To make such a range, the content of all the components having an ethylenically unsaturated group to be blended in the pressure-sensitive adhesive (pressure-sensitive adhesive composition), and the number of ethylenically unsaturated groups in the component (c) and It can be adjusted by adjusting the amount. Moreover, it is also possible to adjust by the kind and quantity of the crosslinking agent of component (a) and the quantity and kind of reactive functional group (α) or (β).
Moreover, it can also adjust by further adding the compound containing an ethylenically unsaturated group which does not react with a reactive functional group ((beta)) by a crosslinking agent.

  When the total number of ethylenically unsaturated groups of all components constituting the pressure-sensitive adhesive is 100, the total number of ethylenically unsaturated groups that only the radiation curable polymer has is the number of ethylenically unsaturated groups of the component (c). 20-90 are more preferable, 30-80 are more preferable, and 40-70 are further more preferable.

Here, the ratio of the total number of ethylenically unsaturated groups possessed only by the radiation curable polymer to the total number of ethylenically unsaturated groups of all components constituting the adhesive is the adhesive layer only from the adhesive tape for semiconductor wafer processing. It can also be confirmed by peeling off and analyzing by instrument.
For example, the peeled adhesive layer is dissolved in a solvent such as toluene, as in the measurement of the gel fraction of the adhesive, and the solution dissolved in the solvent is separated from the portion not dissolved in the solvent. ^It can be evaluated by analyzing ¹ H-NMR and ¹³ C-NMR spectra.
If necessary, gas chromatography or the like may be used.

(Adhesive layer thickness)
The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is selected according to the unevenness of the adherend surface. For example, in the case of bonding to a bumped wafer, the thickness is about 10 to 50 μm thicker than the bump height. It is preferable. Specifically, 10 to 500 μm is preferable, 30 to 400 μm is more preferable, and 50 to 300 μm is further preferable. The pressure-sensitive adhesive may be a multilayer, and in this case, it is desirable that at least the outermost-layer pressure-sensitive adhesive is a radiation curable pressure-sensitive adhesive that satisfies the configuration of the present invention. Further, for example, in the case of following the adherend surface using a base film that is softened by heating, it is desirable that the total thickness of the layers to be followed is in the above range, in which case the outermost pressure-sensitive adhesive is 1 to It is possible to reduce the thickness to about 100 μm.

(Adhesive layer or adhesive properties)
In the present invention, the gel fraction of the pressure-sensitive adhesive (pressure-sensitive adhesive layer) before radiation curing is 30 to 80%.
The gel fraction is preferably 30 to 76%, more preferably 40 to 70%, and still more preferably 50 to 68%.

  The gel fraction is the pressure-sensitive adhesive before it is dissolved with the mass of the gel part and the solvent. It is a ratio (percentage) to the mass.

Specifically, the gel fraction is obtained by cutting a semiconductor wafer processing pressure-sensitive adhesive tape into A5 size and peeling off the separator. The mass of this test piece is measured. Then, it is immersed in toluene for 24 hours. Here, the base material film side is fixed to the bottom of the heavy object or the container so that the test piece does not float on the toluene surface, and the adhesive surface as the adhesive layer is exposed to the toluene solvent. Thereafter, the test piece is taken out and dried at 50 ° C. for 24 hours. On the other hand, it collect | recovers through a mesh also from a toluene solvent. Measure the mass of the residue on the specimen and mesh.
Subtract the mass of the base film and mesh. Here, the mesh measures the mass of the mesh itself, and the base film is cut out of the base film only into the same area and measured, or is calculated from the thickness and density.
Based on these values, the gel fraction of the pressure-sensitive adhesive (pressure-sensitive adhesive layer) before radiation curing is determined according to the following formula.

Gel fraction (%) =
{(Total weight of test piece and mesh after immersion in toluene) − (mass of base film of test piece + mass of mesh)} ÷ (mass of test piece before immersion in toluene−mass of base film of test piece) × 100

In the above, the base polymer and the compound having an ethylenically unsaturated group that are not in a crosslinked structure by a crosslinking reaction by a crosslinking agent are eluted in toluene.
For this reason, the gel fraction is a measure of the degree of crosslinking.
The gel fraction can be adjusted by the type of base polymer constituting the pressure-sensitive adhesive, the type and blending amount of the crosslinking agent, the content of a compound that does not react with the curing agent, and the like.

In the present invention, the storage elastic modulus at 25 ° C. of the adhesive (adhesive layer) is preferably 20,000 to 300,000 Pa, more preferably 30,000 to 100,000 Pa, and 40,000 to 70,000 Pa. Is more preferable.
In addition, when bonding, heating or cooling the adhesive tape for semiconductor wafer processing, it is desirable to become the said storage elastic modulus in the temperature to bond. The pasting temperature is generally, for example, 20 to 100 ° C.

  The storage modulus of the pressure-sensitive adhesive (pressure-sensitive adhesive layer) is obtained by laminating a coated and dried pressure-sensitive adhesive on a release-treated separator, and punching it into a pellet with a thickness of about 2 mm and a diameter of about 8 mmφ. It can be measured by the following procedure.

  The storage elastic modulus is measured at a frequency of 6.28 rad / sec using a dynamic viscoelasticity measuring apparatus (for example, ARES manufactured by TA Instruments). About temperature, the value of the storage elastic modulus in 25 degreeC and the bonding temperature is measured.

  A storage elastic modulus can be adjusted with the kind of adhesive, the kind of component contained in an adhesive, content, and a crosslinking degree.

In addition, the storage elastic modulus of the pressure-sensitive adhesive after curing by radiation irradiation (after irradiation and curing of the whole pressure-sensitive adhesive layer so that the cumulative irradiation amount is 500 mJ / cm ^{2 in} terms of ultraviolet ray) is 1.0 ×. 10 ⁵ Pa or more is preferable.

In the present invention, the TTV value is preferably 5 or less, and more preferably 4 or less.
The TTV value is a difference between the maximum value and the minimum value of the measured thickness of a semiconductor wafer after grinding with a film thickness meter such as a non-contact type laser manufactured by ISIS Co., Ltd. .

In the present invention, the ratio (C / Si) of carbon (C) element and silicon (Si) element, measured using X-ray photoelectron spectroscopy (XPS), is preferably less than 1.0, more preferably less than 0.5. preferable.
<Other layers>
The pressure-sensitive adhesive tape for processing a semiconductor wafer of the present invention may be provided with other layers such as an adhesive layer.

<Release liner>
The pressure-sensitive adhesive tape for processing a semiconductor wafer may have a release liner on the pressure-sensitive adhesive layer. As the release liner, a polyethylene terephthalate film subjected to silicone release treatment or the like is used. If necessary, a polypropylene film that is not subjected to silicone release treatment may be used.

<< Use of adhesive tape for semiconductor wafer processing >>
The adhesive tape for processing a semiconductor wafer of the present invention can be used as, for example, an adhesive tape for protecting a semiconductor or the like, or an adhesive tape for fixing a semiconductor wafer or the like.
Specifically, adhesive tape for silicon semiconductor back grinding, adhesive tape for compound semiconductor back grinding, adhesive tape for silicon semiconductor dicing, adhesive tape for compound semiconductor dicing, adhesive tape for semiconductor package dicing, adhesive tape for glass dicing, ceramic dicing It can be used as surface protection for electronic parts, semiconductor parts, or optical parts, such as adhesive tapes. In particular, it is useful as an adhesive tape for back grinding for semiconductor wafers having steps and protrusions.

<< Method for producing adhesive tape for semiconductor wafer processing >>
In this invention, an adhesive layer prepares the adhesive (adhesive composition) which consists of an adhesive with a gel fraction of 30 to 80%, and forms an adhesive layer on a base film.
Here, the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive contains at least each of the component (a), the component (b) and the component (c).
The method for forming the pressure-sensitive adhesive layer on the substrate film may be any method, but a method in which the pressure-sensitive adhesive composition is applied and dried is preferred.
The pressure-sensitive adhesive composition may be a pressure-sensitive adhesive composition containing a solvent for application to the pressure-sensitive adhesive (in the present invention, in particular, when referred to as a composition, it is used to include a solvent). The preparation method is as described in <Adhesive layer (adhesive)> described above.

<< Semiconductor wafer processing method >>
The semiconductor wafer processing method of the present invention is a semiconductor wafer processing method using the semiconductor wafer processing adhesive tape of the present invention.
The adhesive tape for semiconductor wafer processing of the present invention may be used in any process as long as it is a semiconductor wafer processing process. For example, a semiconductor wafer back surface grinding process, a dicing process, a dicing die bonding process, and the like are preferable.

The adhesive tape for processing a semiconductor wafer of the present invention is preferably used by being bonded to a semiconductor wafer surface having surface irregularities of 10 μm or more.
It is more preferable to apply to a semiconductor wafer having a surface unevenness [height of bumps (electrodes)] of 20 to 400 μm, and more preferable to apply to a semiconductor wafer having a surface roughness of 20 to 100 μm.

  The arrangement density (high density) of bumps on the surface of the semiconductor wafer is not particularly limited. For example, the pitch is 2.0 times the height of the bumps (from the apex in the bump height direction to the next arrangement). Can be applied to a bump having a pitch 1.5 times the bump height. It is also used for semiconductor wafers in which bumps are uniformly arranged on the entire surface.

The thickness of the semiconductor wafer is preferably 20 to 500 μm, more preferably 25 to 200 μm, and even more preferably 25 to 100 μm in the thickness of the semiconductor wafer that has been back-ground by a processing method using a semiconductor wafer processing adhesive tape.
By using the adhesive tape for processing a semiconductor wafer of the present invention, a thin film semiconductor wafer can be obtained with a high yield. This semiconductor wafer processing method is suitable as a manufacturing method for thin-film grinding of a semiconductor wafer with an electrode of 50 μm or less.

  The method for producing a semiconductor wafer according to the present invention includes a step of peeling the pressure-sensitive adhesive tape for processing a semiconductor wafer by irradiating with radiation, particularly ultraviolet rays, after the pressure-sensitive adhesive tape for processing a semiconductor wafer according to the present invention is bonded to the semiconductor wafer surface. It is preferable. Irradiation can be selected either before or after grinding of the semiconductor wafer.

Specifically, first, the adhesive tape for semiconductor wafer processing of the present invention is bonded to the circuit pattern surface (front surface) of the semiconductor wafer so that the adhesive layer becomes the bonding surface. Next, the surface side of the semiconductor wafer having no circuit pattern is ground until the thickness of the semiconductor wafer reaches a predetermined thickness, for example, 20 to 500 μm. After that, the surface on which the adhesive tape for processing semiconductor wafers is attached is placed on the heating adsorption table, and in that state, the dicing tape or dicing die bonding is applied to the ground surface without the circuit pattern of the semiconductor wafer. You may paste a film.
A dicing process is performed, and then a heat seal type (thermal fusion type) or adhesive type release tape is adhered to the back surface of the base film of the semiconductor wafer processing adhesive tape, and the semiconductor wafer processing adhesive tape is attached to the semiconductor wafer. Peel off.
Although the above-described grinding step to dicing step have been described, the processing by the pre-dicing step and the pre-stealth step is also useful in terms of simplifying the processing step and improving the bending strength of the semiconductor chip.

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

(Preparation of adhesive composition)
Adhesive compositions 2A to 2K were prepared as follows.

1) Preparation of pressure-sensitive adhesive composition 2A For 100 parts by mass of a copolymer consisting of 80 parts by mass of 2-ethylhexyl acrylate, 15 parts by mass of 2-hydroxyethyl acrylate, and 5 parts by mass of methacrylic acid, and having a mass average molecular weight of 500,000. And 100 parts by mass of urethane acrylate oligomer having a weight average molecular weight of 1,000 having a hydroxy group as a reactive functional group (β) and a polyisocyanate coronate L [manufactured by Nippon Polyurethane Industry Co., Ltd. ] 5.0 parts by mass, SPEDCURE BKL [manufactured by DKSH Japan Co., Ltd.] 5.0 parts by mass was added and mixed as a photopolymerization initiator to obtain an adhesive composition 2A.

2) Preparation of adhesive composition 2B Except for changing the compounding amount of the urethane acrylate oligomer used in the preparation of adhesive composition 2A from 100 parts by mass to 70 parts by mass, the same as the preparation of adhesive composition 2A, An adhesive composition 2B was obtained.

3) Preparation of pressure-sensitive adhesive composition 2C The amount of urethane acrylate oligomer used in the preparation of pressure-sensitive adhesive composition 2A was changed from 100 parts by weight to 20 parts by weight. A pressure-sensitive adhesive composition 2C was obtained in the same manner as the preparation of the pressure-sensitive adhesive composition 2A except that 70 parts by mass of 1,000 urethane acrylate oligomers were further added.

4) Preparation of pressure-sensitive adhesive composition 2D The amount of urethane acrylate oligomer used in the preparation of pressure-sensitive adhesive composition 2A was changed from 100 parts by weight to 50 parts by weight. An adhesive composition 2D was obtained in the same manner as the preparation of the adhesive composition 2A except that 50 parts by mass of 1,000 urethane acrylate oligomers were further added.

5) Preparation of pressure-sensitive adhesive composition 2E The blending amount of the urethane acrylate oligomer used in the preparation of pressure-sensitive adhesive composition 2A was changed from 100 parts by weight to 70 parts by weight. A pressure-sensitive adhesive composition 2E was obtained in the same manner as the pressure-sensitive adhesive composition 2A except that 20 parts by mass of 1,000 urethane acrylate oligomers were further added.

6) Preparation of pressure-sensitive adhesive composition 2F For 100 parts by mass of a copolymer consisting of 80 parts by mass of 2-ethylhexyl acrylate, 15 parts by mass of 2-hydroxyethyl acrylate, and 5 parts by mass of methacrylic acid, and having a mass average molecular weight of 500,000. And 100 parts by weight of urethane acrylate oligomer having a weight average molecular weight of 2,000 having a hydroxyl group as a reactive functional group (β) and a polyisocyanate coronate L [manufactured by Nippon Polyurethane Industry Co., Ltd. ] 3.0 parts by mass, TETRAD-X of epoxy resin [Mitsubishi Gas Chemical Co., Ltd.] 0.5 parts by mass, SPEDCURE BKL [manufactured by DKSH Japan Co., Ltd.] 5.0 parts by mass as a photopolymerization initiator And mixed to obtain an adhesive composition 2F.

7) Preparation of pressure-sensitive adhesive composition 2G The blending amount of the urethane acrylate oligomer used in the preparation of pressure-sensitive adhesive composition 2A was changed from 100 parts by weight to 10 parts by weight. A pressure-sensitive adhesive composition 2G was obtained in the same manner as the pressure-sensitive adhesive composition 2A except that 90 parts by mass of 1,000 urethane acrylate oligomers were further added.

8) Preparation of pressure-sensitive adhesive composition 2H For 100 parts by mass of copolymer consisting of 80 parts by mass of 2-ethylhexyl acrylate, 15 parts by mass of 2-hydroxyethyl acrylate, and 5 parts by mass of methacrylic acid, and having a mass average molecular weight of 500,000. 100 parts by mass of a urethane acrylate oligomer having a weight average molecular weight of 1,000, which is acrylate pentafunctional and has no hydroxy group, and a polyisocyanate coronate L [manufactured by Nippon Polyurethane Industry Co., Ltd.] 4.0 parts by mass Then, 5.0 parts by mass of SPEEDCURE BKL [manufactured by DKSH Japan Co., Ltd.] as a photopolymerization initiator was added and mixed to obtain an adhesive composition 2H.

9) Preparation of pressure-sensitive adhesive composition 2I A copolymer obtained by copolymerizing 62 parts by mass of 2-ethylhexyl acrylate, 18 parts by mass of 2-hydroxyethyl acrylate, 9 parts by mass of methyl methacrylate, and 1 part by mass of methacrylic acid ( The polyisocyanate coronate L [100 parts by mass of molecular weight 700,000) and 100 parts by mass of a copolymer obtained from 10 parts by mass of 2- (methacryloyloxy) ethyl isocyanate as a radiation reactive group [ Nippon Polyurethane Industry Co., Ltd.] 2.0 parts by mass, and SPEDCURE BKL [manufactured by DKSH Japan Co., Ltd.] 3.0 parts by mass as a photopolymerization initiator were added and mixed to obtain an adhesive composition 2I.

10) Preparation of pressure-sensitive adhesive composition 2J The amount of crosslinking agent Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.) used in the preparation of pressure-sensitive adhesive composition 2I was changed from 2.0 parts by weight to 1.0 part by weight. Except having carried out, it carried out similarly to preparation of the adhesive composition 2I, and obtained the adhesive composition 2J.

11) Preparation of pressure-sensitive adhesive composition 2K The amount of crosslinking agent Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.) used in the preparation of pressure-sensitive adhesive composition 2I was changed from 2.0 parts by weight to 0.5 parts by weight. A pressure-sensitive adhesive composition 2K was obtained in the same manner as in the preparation of the pressure-sensitive adhesive composition 2I except that.

Example 1
The pressure-sensitive adhesive composition 2A was applied on a 38 μm thick polyethylene terephthalate (PET) separator so that the film thickness after drying was 90 μm, dried, and then a 140 μm thick ethylene-vinyl acetate copolymer. An adhesive tape for processing a semiconductor wafer having a thickness of 230 μm was manufactured by laminating with a base film made of (EVA) film.

Example 2
In Example 1, the adhesive tape for semiconductor wafer processing was manufactured like Example 1 except having changed adhesive composition 2A into adhesive composition 2B.

Example 3
In Example 1, a pressure-sensitive adhesive tape for semiconductor wafer processing was produced in the same manner as Example 1 except that the pressure-sensitive adhesive composition 2A was changed to the pressure-sensitive adhesive composition 2C.

Example 4
In Example 1, the adhesive tape for semiconductor wafer processing was manufactured like Example 1 except having changed adhesive composition 2A into adhesive composition 2D.

Example 5
In Example 1, the adhesive tape for semiconductor wafer processing was manufactured like Example 1 except having changed adhesive composition 2A into adhesive composition 2E.

Example 6
In Example 1, the adhesive tape for semiconductor wafer processing was manufactured like Example 1 except having changed adhesive composition 2A into adhesive composition 2F.

Comparative Example 1
In Example 1, the adhesive tape for semiconductor wafer processing was manufactured like Example 1 except having changed adhesive composition 2A into adhesive composition 2G.

Comparative Example 2
In Example 1, the adhesive tape for semiconductor wafer processing was manufactured like Example 1 except having changed adhesive composition 2A into adhesive composition 2H.

Comparative Example 3
In Example 1, a pressure-sensitive adhesive tape for semiconductor wafer processing was produced in the same manner as in Example 1, except that the pressure-sensitive adhesive composition 2A was changed to the pressure-sensitive adhesive composition 2I.

Comparative Example 4
In Example 1, the adhesive tape for semiconductor wafer processing was manufactured like Example 1 except having changed adhesive composition 2A into adhesive composition 2J.

Comparative Example 5
In Example 1, a pressure-sensitive adhesive tape for semiconductor wafer processing was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition 2A was changed to the pressure-sensitive adhesive composition 2K.

(Evaluation test)
In the adhesive tapes for semiconductor wafer processing of Examples 1 to 6 and Comparative Examples 1 to 5, as shown below, when the total number of ethylenically unsaturated groups of all components constituting the adhesive is 100, the component ( The total number of ethylenically unsaturated groups of the compound having a reactive functional group that reacts with the crosslinking agent as c) was determined.
Further, the gel fraction of the pressure-sensitive adhesive was measured as follows, and dust intrusion and adhesive residue, TTV of the semiconductor wafer after grinding, and contamination of the semiconductor wafer were evaluated.

[Gel fraction of adhesive]
Each semiconductor wafer processing adhesive tape was cut into A5 size and the separator was peeled off to make a test piece. The mass of this test piece was measured. Subsequently, it was immersed in toluene for 24 hours. Here, the base film side was fixed to the bottom of the heavy object or the container so that the test piece did not float on the toluene surface, and the adhesive surface as the adhesive layer was exposed to the toluene solvent. Thereafter, the test piece was taken out and dried at 50 ° C. for 24 hours. On the other hand, it collect | recovered through the mesh also from the toluene solvent. The mass of the residue on the test piece and the mesh was measured.
Substrate film and mesh mass was subtracted. Here, the mass of the mesh itself was measured, and the base film was mass-measured by cutting only the base film into the same area.
Based on these values, the gel fraction of the pressure-sensitive adhesive (pressure-sensitive adhesive layer) before radiation curing was determined according to the following formula.

Gel fraction (%) =
{(Total weight of test piece and mesh after immersion in toluene) − (mass of base film of test piece + mass of mesh)} ÷ (mass of test piece before immersion in toluene−mass of base film of test piece) × 100

[Evaluation of dust penetration and adhesive residue]
An adhesive tape for processing a semiconductor wafer was bonded to an 8-inch diameter semiconductor wafer having copper pillar bumps having a height of 40 μm and a pitch of 80 μm on the surface at a bonding temperature of 25 ° C.
The ground semiconductor wafer with tape was irradiated with ultraviolet rays of 500 mJ / cm ² and the semiconductor wafer processing adhesive tape was peeled off using an Instron tensile tester (twin column tabletop model 5567).
The semiconductor wafer after peeling was observed, and dust intrusion and adhesive residue were observed with a microscope. The products without dust ingress and those without adhesive residue were evaluated as “good”. On the other hand, the case where dust intrusion was observed and the case where adhesive residue was observed was marked as “x”.

[Evaluation of TTV for semiconductor wafers]
The thickness of the ground semiconductor wafer was measured with a non-contact type laser film thickness meter manufactured by ISIS Co., Ltd., and the difference between the maximum value and the minimum value of the measured thickness of the semiconductor wafer was defined as the TTV value.
As for the evaluation rank, a TTV value of 4 or less was “◎”, 4 was 5 or less “◯”, 5 was 6 or less “Δ”, and 6 was over “6”.

[Evaluation of contamination of semiconductor wafers]
An adhesive tape for processing a semiconductor wafer to be evaluated was bonded to an 8-inch diameter mirror wafer, and left for 1 hour, and then irradiated with 500 mJ / cm ² of ultraviolet rays. Thereafter, the semiconductor wafer processing adhesive tape was peeled off, and the contamination of the wafer central portion was measured using X-ray photoelectron spectroscopy (XPS). The ratio (C / Si) of carbon (C) element and silicon (Si) element was determined.
The evaluation rank is such that the ratio (C / Si) value is less than 0.3 as “◎”, 0.3 to less than 0.5 as “◯”, 0.5 to less than 1.0 as “Δ”, 1 The above was designated as “x”.

The obtained results are summarized in Tables 1 and 2 below.
Here, the total number of ethylenically unsaturated groups of component (c) is a value when the total number of ethylenically unsaturated groups of all components constituting the pressure-sensitive adhesive is 100.

From Tables 1 and 2, the pressure-sensitive adhesive is at least a component (a) crosslinking agent, component (b), a (meth) acrylic copolymer having a reactive functional group that reacts with the crosslinking agent, and components. Example 1 of the present invention comprising (c) a compound having an ethylenically unsaturated group and a reactive functional group that reacts with the crosslinking agent, and the gel fraction of the pressure-sensitive adhesive being 30 to 80%. It can be seen that the adhesive tapes for processing semiconductor wafers No. 6 to 6 are excellent with little dust intrusion and no adhesive residue.
In particular, the total number of ethylenically unsaturated groups contained in the compound having a reactive functional group that crosslinks with the copolymer and an ethylenically unsaturated group in the component (c) is ethylene of all the components constituting the pressure-sensitive adhesive. When the total number of the unsaturated groups is 100, it can be seen that the adhesive tapes for processing semiconductor wafers of Examples 3 to 5, which are 20 to 90, have good followability to bump wafers, and therefore TTV is more excellent.
In contrast, Comparative Examples 1 and 5 having a gel fraction lower than 30% and Comparative Example 2 using a polymer having a crosslinked structure and having no ethylenically unsaturated groups resulted in adhesive residue.
On the other hand, in Comparative Examples 3 and 4 having a polymer having an ethylenically unsaturated group in the side chain, the followability was insufficient and wafer breakage was observed. Therefore, TTV, dust intrusion and adhesive residue are described as reference values.

  The adhesive tape for processing a semiconductor wafer of the present invention is excellent in evaluation of any of dust intrusion and adhesive residue, TTV of a semiconductor wafer after grinding, and contamination of the semiconductor wafer as described above. It can be seen that the adhesive tape is excellent as an adhesive tape for processing a semiconductor wafer used by bonding to a semiconductor wafer surface having an unevenness of 40 μm and a bump height of 10 μm or more.

Claims (9)

An adhesive tape for processing a semiconductor wafer having an adhesive layer on at least one surface of a base film,
The pressure-sensitive adhesive of the pressure-sensitive adhesive layer comprises at least each of component (a), component (b) and component (c),
The component (a) is a crosslinking agent, the component (b) is a (meth) acrylic copolymer having a reactive functional group that reacts with the crosslinking agent of the component (a), and the component (c) ) Is a compound having an ethylenically unsaturated group and a reactive functional group that reacts with the crosslinking agent of component (a), and
A pressure-sensitive adhesive tape for processing semiconductor wafers, wherein the pressure-sensitive adhesive has a gel fraction of 30 to 80%.   The total number of ethylenically unsaturated groups of the component (c) is 20 to 90, where 100 is the total number of ethylenically unsaturated groups of all components constituting the pressure-sensitive adhesive. Item 2. An adhesive tape for processing a semiconductor wafer according to Item 1.   The pressure-sensitive adhesive tape for semiconductor wafer processing according to claim 1 or 2, wherein the compound of component (c) is urethane acrylate.   The crosslinking agent having a reactive functional group different from the crosslinking agent of component (a) as component (d) in addition to the crosslinking agent of component (a). The adhesive tape for semiconductor wafer processing of any one. A method for producing an adhesive tape for processing a semiconductor wafer having an adhesive layer on at least one surface of a base film,
The pressure-sensitive adhesive layer is made of a pressure-sensitive adhesive having a gel fraction of 30 to 80%,
The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer contains at least each of the component (a), the component (b) and the component (c),
The component (a) is a crosslinking agent, the component (b) is a (meth) acrylic copolymer having a reactive functional group that reacts with the crosslinking agent of the component (a), and the component (c) ) Is a compound having an ethylenically unsaturated group and a reactive functional group that reacts with the crosslinking agent of component (a),
The manufacturing method of the adhesive tape for semiconductor wafer processing characterized by forming the said adhesive layer on the said base film with the said adhesive composition.   When the total number of ethylenically unsaturated groups of all components having an ethylenically unsaturated group contained in the pressure-sensitive adhesive composition is 100, the total number of ethylenically unsaturated groups of the component (c) is 20 It is -90, The manufacturing method of the adhesive tape for semiconductor wafer processing of Claim 5 characterized by the above-mentioned.   The method for producing an adhesive tape for semiconductor wafer processing according to claim 5 or 6, wherein the compound of component (c) is urethane acrylate.   The crosslinking agent having a reactive functional group different from the crosslinking agent of the component (a) as the component (d) in addition to the crosslinking agent of the component (a). The manufacturing method of the adhesive tape for semiconductor wafer processing of any one of Claims 1.   After sticking the adhesive tape for semiconductor wafer processing of any one of Claims 1-4 on the semiconductor wafer surface with surface unevenness of 10 micrometers or more, it irradiates with an ultraviolet-ray and peels the adhesive tape for semiconductor wafer processing A method for processing a semiconductor wafer, comprising a step.