WO2019008810A1 - Adhesive sheet for stealth dicing, and production method for semiconductor device - Google Patents

Abstract

An adhesive sheet 1 for stealth dicing which is at least used in the cutting and separation of a semiconductor wafer having a modified layer formed in the interior thereof into individual chips in a room-temperature environment, wherein the adhesive sheet 1 for stealth dicing is provided with a substrate 11 and an adhesive layer 12 layered upon one surface side of the substrate 11, and when the adhesive sheet 1 for stealth dicing is adhered to a silicon wafer via the adhesive layer 12, the shearing force at 23℃ at the interface of the adhesive layer 12 and the silicon wafter is in the range of 70 N/(3 mm×20 mm) to 250 N/(3 mm×20 mm). This adhesive sheet for stealth dicing makes it possible to satisfactorily dice a semiconductor wafer into chips even when expansion is performed at room temperature.

Description

Adhesive sheet for stealth dicing and method of manufacturing semiconductor device

The present invention relates to a pressure-sensitive adhesive sheet for stealth dicing used for stealth dicing (registered trademark) processing, and a method of manufacturing a semiconductor device using the pressure-sensitive adhesive sheet for stealth dicing.

Conventionally, when manufacturing a chip-like semiconductor device from a semiconductor wafer, a blade dicing process is performed in which a semiconductor wafer is cut by a rotary blade to spray a liquid for cleaning and the like and the chip is obtained. It was common. However, in recent years, stealth dicing which can be divided into chips in a dry manner has been adopted. In stealth dicing, for example, the semiconductor wafer attached to the dicing sheet is irradiated with a laser beam having a large opening (NA) to minimize damage to the vicinity of the surface of the semiconductor wafer, and preliminary inside the semiconductor wafer. Form a modified layer. Thereafter, by expanding the dicing sheet, a force is applied to the semiconductor wafer to cut and separate into individual chips.

In recent years, it has been required to stack another chip on the chip manufactured as described above or to bond the chip onto a film substrate. Then, from a face-up type mounting in which a circuit on a chip and a circuit on another chip or substrate are connected by a wire, an electrode formation surface of a chip provided with a projecting electrode and a circuit on another chip or substrate And flip-chip mounting in which the electrodes are directly connected to each other, and transition to Through Silicon Via (TSV) are performed in some fields. In response to the demand for stacking and bonding of chips in flip chip mounting and the like, a method has been proposed in which a chip with an electrode is fixed to another chip or a film substrate using an adhesive.

Then, in order to be easily applied to such applications, the semiconductor wafer with an electrode or the modified semiconductor wafer with an electrode to which a dicing sheet is attached on the surface opposite to the electrode formation surface in the process of the above manufacturing method It has been proposed that a film-like adhesive is laminated on the electrode forming surface, and the electrode-mounted chip divided in the expanding step is provided with an adhesive layer on the electrode forming surface. As such an adhesive layer, an adhesive film called a die attach film (DAF) or a nonconductive adhesive film (NCF) is used.

Patent Document 1 discloses that a DAF is attached to a wafer, a stealth dicing process is performed, and then, the wafer is separated into chips by expanding and the DAF is divided at the same time.

JP 2005-19962 gazette

Since the above-mentioned DAF and NCF have the property of embrittlement in a low temperature region, in order to improve the dividability of the DAF and NCF, a cool expand process of performing the above expansion in a low temperature environment of about -20 ° C to 10 ° C is performed. There is more to do.

However, since it is necessary to introduce equipment capable of realizing temperature management in order to carry out the cool expanding step, the initial cost becomes higher as compared with the case of expanding at room temperature. Therefore, from the viewpoint of cost, it is desirable to use a method of expanding at room temperature instead of the cool expanding step.

The present invention has been made in view of the above-described actual situation, and a pressure-sensitive adhesive sheet for stealth dicing and a semiconductor capable of satisfactorily dividing a semiconductor wafer into chips even when expanding at room temperature. The purpose is to provide a method of manufacturing a device.

In order to achieve the above object, firstly, the present invention is at least an adhesive sheet for stealth dicing which is used to cut and separate a semiconductor wafer having a modified layer formed therein into individual chips under a room temperature environment. A substrate and a pressure-sensitive adhesive layer laminated on one side of the substrate, wherein the stealth dicing pressure-sensitive adhesive sheet is attached to a silicon wafer via the pressure-sensitive adhesive layer, An adhesive sheet for stealth dicing characterized in that a shear force at 23 ° C. of an interface between an adhesive layer and the silicon wafer is 70 N / (3 mm × 20 mm) or more and 250 N / (3 mm × 20 mm) or less. (Invention 1).

In the pressure-sensitive adhesive sheet for stealth dicing according to the invention (Invention 1), the pressure-sensitive adhesive sheet for stealth dicing and the pressure-sensitive adhesive sheet for stealth dicing when the shear force at 23 ° C. is in the above range when expanding at room temperature. Misalignment at the interface with the semiconductor wafer stacked thereon is less likely to occur. As a result, the force for pulling the semiconductor wafer in the direction of the peripheral edge, which is generated by the expansion of the adhesive sheet for stealth dicing, tends to be concentrated on the modified layer, resulting in favorable division of the semiconductor wafer in the modified layer. Therefore, even in the case of expanding at room temperature, the occurrence of problems such as division failure and chip breakage can be suppressed, and a chip that has been favorably separated can be obtained.

In the said invention (invention 1), it is preferable that the said chip | tip of the minimum side length is 2 mm or more and 30 mm or less (invention 2).

In the above inventions (Inventions 1 and 2), the semiconductor wafer preferably has a thickness of 10 μm or more and 1000 μm or less (Invention 3).

In the above inventions (Inventions 1 to 3), the pressure-sensitive adhesive layer is preferably composed of an energy ray-curable adhesive (Invention 4).

In the above inventions (Inventions 1 to 4), the storage elastic modulus at 23 ° C. of the base is preferably 10 MPa or more and 600 MPa or less (Invention 5).

Secondly, in the present invention, a bonding step of bonding the pressure-sensitive adhesive layer and the semiconductor wafer of the pressure-sensitive adhesive sheet for the stealth dicing (inventions 1 to 5), and a modified step of forming a modified layer inside the semiconductor wafer , And expanding the adhesive sheet for stealth dicing under a room temperature environment to cut and separate the semiconductor wafer having the modified layer formed therein into individual chips. The present invention provides a method of manufacturing a semiconductor device (invention 6).

In the above invention (Invention 6), the semiconductor wafer bonded to the adhesive sheet for stealth dicing further includes a laminating step of laminating a bonding film on the surface opposite to the adhesive sheet side for stealth dicing. Is preferable (invention 7).

According to the present invention, there is provided a pressure-sensitive adhesive sheet for stealth dicing and a method of manufacturing a semiconductor device capable of satisfactorily separating a semiconductor wafer into chips even when expanding at room temperature.

It is a top view explaining the measuring method of shear force concerning example 1 of an examination. It is sectional drawing explaining the measuring method of the shear force which concerns on Experiment 1. FIG.

Hereinafter, embodiments of the present invention will be described.
[Adhesive sheet for stealth dicing]
The adhesive sheet for stealth dicing according to one embodiment of the present invention is used to cut and separate at least a semiconductor wafer having a modified layer formed therein into individual chips under a room temperature environment. Here, room temperature environment means, for example, an environment of 5 ° C. or more, particularly preferably 10 ° C. or more, and more preferably 15 ° C. or more. Further, room temperature environment means, for example, an environment of 45 ° C. or less, particularly preferably 40 ° C. or less, more preferably 35 ° C. or less. The above temperature range can be easily achieved without intentionally controlling the temperature, so that the cost of stealth dicing can be reduced. The term "sheet" in the present specification also includes the concept of "tape".

The adhesive sheet for stealth dicing which concerns on this embodiment is provided with a base material and the adhesive layer laminated | stacked on one surface side of the said base material. The substrate and the pressure-sensitive adhesive layer are preferably laminated directly, but are not limited thereto.

When the adhesive sheet for stealth dicing is attached to a silicon wafer through the adhesive layer of the adhesive sheet for stealth dicing according to this embodiment, the shear force at 23 ° C. of the interface between the adhesive layer and the silicon wafer is 70 N / (3 mm × 20 mm) or more and 250 N / (3 mm × 20 mm) or less.

The pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment has the above-described shear force to expand the stealth dicing pressure-sensitive adhesive sheet on which the semiconductor wafer provided with the modified layer is stacked at room temperature. It is difficult for misalignment at the interface between the adhesive sheet for stealth dicing and the semiconductor wafer to occur. Therefore, the force of pulling the semiconductor wafer generated by the expansion of the pressure-sensitive adhesive sheet for stealth dicing in the direction of the peripheral portion is less likely to be impaired. As a result, the force tends to be concentrated on the modified layer, and the division of the semiconductor wafer in the modified layer is favorably generated. As described above, even in the case of expanding at room temperature, the occurrence of problems such as division failure and breakage of the chip can be suppressed, and a chip separated into pieces can be obtained favorably.

In addition, when the shear force is less than 70 N / (3 mm × 20 mm), particularly when the chip size is small, a gap at the interface between the adhesive sheet for stealth dicing and the semiconductor wafer is easily generated during expansion, and the semiconductor wafer It can not be cut well separated. On the other hand, if the shear force exceeds 250 N / (3 mm × 20 mm), sufficient tack does not appear in the adhesive sheet for stealth dicing, and the obtained chip can not be favorably held on the adhesive sheet for stealth dicing .

From the above viewpoint, the lower limit value of the shear force is preferably 80 N / (3 mm × 20 mm) or more, and particularly preferably 90 N / (3 mm × 20 mm) or more. Further, the upper limit value of the shear force is preferably 200 N / (3 mm × 20 mm) or less, and particularly preferably 180 N / (3 mm × 20 mm) or less. In addition, the measuring method of the said shear force is as showing to the test example mentioned later.

When the semiconductor wafer having the modified layer formed therein is cut and separated into individual chips in a room temperature environment using the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment, the obtained chips have a minimum side length The length is preferably 2 mm to 30 mm, particularly preferably 2.5 mm to 25 mm, and further preferably 3 mm to 20 mm.

When the semiconductor wafer having the modified layer formed therein is cut and separated into individual chips in a room temperature environment using the adhesive sheet for stealth dicing according to the present embodiment, the thickness of the semiconductor wafer is The thickness is preferably 10 μm to 1000 μm or less, particularly preferably 20 μm to 950 μm or less, and further preferably 30 μm to 900 μm or less.

As described above, according to the stealth dicing pressure-sensitive adhesive sheet according to the present embodiment, when expanding at room temperature, the displacement at the interface between the stealth dicing pressure-sensitive adhesive sheet and the semiconductor wafer is suppressed to cut the semiconductor wafer favorably. It can be separated. Therefore, the adhesive sheet for stealth dicing according to the present embodiment is suitable for manufacturing a chip having the above-described chip size at low cost.

1. Pressure-Sensitive Adhesive Layer The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment is not particularly limited as long as it satisfies the above-described shear force. The pressure-sensitive adhesive layer may be composed of a non-energy ray curable pressure sensitive adhesive or may be composed of an energy ray curable pressure sensitive adhesive. As the non-energy ray curable adhesive, those having desired adhesive strength and removability are preferable. For example, acrylic adhesive, rubber adhesive, silicone adhesive, urethane adhesive, polyester adhesive And polyvinyl ether-based pressure-sensitive adhesives can be used. Among these, acrylic pressure-sensitive adhesives which can effectively suppress the detachment of a semiconductor wafer, a chip or the like in a modified layer forming step, an expanding step or the like are preferable.

On the other hand, since the energy ray curable adhesive is cured by energy ray irradiation and the adhesive force is reduced, the energy ray is required to separate the chip obtained by dividing the semiconductor wafer from the adhesive sheet for stealth dicing. It can be easily separated by irradiation.

The energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be a polymer having energy ray-curable properties as a main component, or a non-energy ray-curable polymer (polymer not having energy ray-curable properties) And mixtures thereof with at least one energy ray curable group-containing monomer and / or oligomer. In addition, it may be a mixture of a polymer having energy ray curability and a non-energy ray curable polymer, and a polymer having energy ray curability and a monomer having at least one or more energy ray curable groups and / or It may be a mixture with an oligomer, or may be a mixture of these three.

First, the case where the energy ray-curable pressure-sensitive adhesive contains a polymer having energy ray-curable properties as a main component will be described below.

A polymer having energy ray curability is a (meth) acrylic acid ester (co) polymer (A) (hereinafter referred to as “energy ray,” in which a functional group (energy ray curable group) having energy ray curability is introduced in a side chain It may be referred to as a curable polymer (A). The energy ray-curable polymer (A) is prepared by reacting an acrylic copolymer (a1) having a functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group bonded to the functional group. It is preferable that it is obtained by In the present specification, (meth) acrylic acid ester means both acrylic acid ester and methacrylic acid ester. Other similar terms are also the same.

The acrylic copolymer (a1) preferably contains a constituent unit derived from a functional group-containing monomer and a constituent unit derived from a (meth) acrylic acid ester monomer or a derivative thereof.

The functional group-containing monomer as a constituent unit of the acrylic copolymer (a1) has, in its molecule, a polymerizable double bond and a functional group such as a hydroxy group, a carboxy group, an amino group, a substituted amino group or an epoxy group. It is preferable that it is a monomer which it has.

As the hydroxy group-containing monomer, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (3-hydroxybutyl (meth) acrylate Examples thereof include meta) acrylate, 4-hydroxybutyl (meth) acrylate and the like, and these can be used alone or in combination of two or more.

Examples of carboxy group-containing monomers include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid and the like. These may be used alone or in combination of two or more.

Examples of the amino group-containing monomer or the substituted amino group-containing monomer include aminoethyl (meth) acrylate and n-butylaminoethyl (meth) acrylate. These may be used alone or in combination of two or more.

As the (meth) acrylic acid ester monomer constituting the acrylic copolymer (a1), in addition to an alkyl (meth) acrylate having 1 to 20 carbon atoms in the alkyl group, for example, an alicyclic structure is formed in the molecule The monomer which it has (alicyclic structure containing monomer) is used preferably.

As the alkyl (meth) acrylate, an alkyl (meth) acrylate having, in particular, an alkyl group having 1 to 18 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl Meta) acrylate, 2-ethylhexyl (meth) acrylate or the like is preferably used. One of these may be used alone, or two or more of these may be used in combination.

Examples of the alicyclic structure-containing monomer include cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, isobornyl (meth) acrylate, and dicyclopentenyl (meth) acrylate. And dicyclopentenyl oxyethyl (meth) acrylate are preferably used. One of these may be used alone, or two or more of these may be used in combination.

The acrylic copolymer (a1) preferably contains 1 to 35% by mass, particularly preferably 5 to 30% by mass, and more preferably 10 to 25% by mass of constituent units derived from the functional group-containing monomer. contains. The acrylic copolymer (a1) preferably contains 50 to 99% by mass, particularly preferably 60 to 95% by mass, more preferably 70, of structural units derived from (meth) acrylic acid ester monomers or derivatives thereof. It is contained at a rate of 90% by mass.

The acrylic copolymer (a1) can be obtained by copolymerizing the functional group-containing monomer as described above with a (meth) acrylic acid ester monomer or a derivative thereof in a conventional manner. Dimethyl acrylamide, vinyl formate, vinyl acetate, styrene or the like may be copolymerized.

By reacting the acrylic copolymer (a1) having the functional group-containing monomer unit with the unsaturated group-containing compound (a2) having a functional group binding to the functional group, an energy ray-curable polymer (A) ) Is obtained.

The functional group which an unsaturated group containing compound (a2) has can be suitably selected according to the kind of functional group of the functional group containing monomer unit which an acryl-type copolymer (a1) has. For example, when the functional group possessed by the acrylic copolymer (a1) is a hydroxy group, an amino group or a substituted amino group, an isocyanate group or an epoxy group is preferable as the functional group possessed by the unsaturated group-containing compound (a2). When the functional group possessed by the copolymer (a1) is an epoxy group, the functional group possessed by the unsaturated group-containing compound (a2) is preferably an amino group, a carboxy group or an aziridinyl group.

In the unsaturated group-containing compound (a2), at least one, preferably 1 to 6, and more preferably 1 to 4 energy ray-polymerizable carbon-carbon double bonds are contained in one molecule. ing. Specific examples of such unsaturated group-containing compound (a2) include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1- Bisacryloyloxymethyl) ethyl isocyanate; acryloyl monoisocyanate compound obtained by reaction of diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth) acrylate; diisocyanate compound or polyisocyanate compound, polyol compound, hydroxyethyl (meth) Acryloyl monoisocyanate compounds obtained by reaction with acrylates; glycidyl (meth) acrylates; (meth) acrylic acid, 2- (1) And -aziridinyl) ethyl (meth) acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline and the like.

The unsaturated group-containing compound (a2) is preferably 50 to 95 mol%, particularly preferably 60 to 93 mol%, and more preferably 50 to 95 mol%, relative to the molar number of the functional group-containing monomer of the acrylic copolymer (a1). It is used at a rate of 70 to 90 mol%.

In the reaction of the acrylic copolymer (a1) with the unsaturated group-containing compound (a2), the functional group of the acrylic copolymer (a1) and the functional group of the unsaturated group-containing compound (a2) Depending on the combination, the reaction temperature, pressure, solvent, time, presence or absence of catalyst, and type of catalyst can be appropriately selected. Thereby, the functional group present in the acrylic copolymer (a1) and the functional group in the unsaturated group-containing compound (a2) react with each other, and the unsaturated group in the acrylic copolymer (a1) When introduced into the side chain, an energy ray-curable polymer (A) is obtained.

The weight-average molecular weight (Mw) of the energy ray-curable polymer (A) thus obtained is preferably 10,000 or more, particularly preferably 150,000 to 1,500,000, and more preferably 200,000 to 100. It is preferable that it is ten thousand. In addition, the weight average molecular weight (Mw) in this specification is a value of standard polystyrene conversion measured by the gel permeation chromatography method (GPC method).

Even when the energy ray-curable pressure-sensitive adhesive is mainly composed of an energy ray-curable polymer such as an energy ray-curable polymer (A), the energy ray-curable pressure-sensitive adhesive is an energy ray-curable monomer And / or may further contain an oligomer (B).

As the energy ray-curable monomer and / or oligomer (B), for example, an ester of polyhydric alcohol with (meth) acrylic acid can be used.

Examples of such an energy ray-curable monomer and / or oligomer (B) include monofunctional acrylic esters such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, penta Erythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene glycol Polyfunctional acrylic acid esters such as di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, polyester oligo (meth) acrylate, polyurethane oligo (meth Acrylate, and the like.

When the energy ray-curable monomer and / or oligomer (B) is blended with the energy ray-curable polymer (A), the energy ray-curable monomer and / or oligomer in the energy ray-curable adhesive (B) The content of) is preferably 0.1 to 180 parts by mass, particularly preferably 60 to 150 parts by mass with respect to 100 parts by mass of the energy ray-curable polymer (A).

Here, in the case of using ultraviolet rays as energy rays for curing the energy ray curable adhesive, it is preferable to add a photopolymerization initiator (C), and by using this photopolymerization initiator (C), The polymerization curing time and the light irradiation amount can be reduced.

Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, methyl benzoin benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethyl thiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloroanthraquinone, (2,4, 6-trimethylbenzyl diphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate, oligo {2-hydroxy-2-me Le-1- [4- (1-propenyl) phenyl] propanone}, and 2,2-dimethoxy-1,2-and the like. These may be used alone or in combination of two or more.

When the photopolymerization initiator (C) contains the energy ray-curable polymer (A) (energy ray-curable monomer and / or oligomer (B), the energy ray-curable polymer (A) and the energy 0.1 to 10 parts by mass, in particular 0.5 to 6 parts by mass, with respect to 100 parts by mass of the total amount of linear curable monomer and / or oligomer (B) 100 parts by mass) Is preferred.

In the energy ray-curable pressure-sensitive adhesive, in addition to the above components, other components may be appropriately blended. Other components include, for example, non-energy ray curable polymer component or oligomer component (D), crosslinking agent (E), polymerizable branched polymer (F) and the like.

Examples of the non-energy ray curable polymer component or oligomer component (D) include polyacrylic esters, polyesters, polyurethanes, polycarbonates, polyolefins, hyperbranched polymers and the like, and the weight average molecular weight (Mw) is 3,000 to 2,500,000. Preferred are polymers or oligomers of By blending the component (D) into an energy ray curable adhesive, tackiness and releasability before curing, strength after curing, easy releasability from an adherend, adhesiveness with other layers, preservation Stability and the like can be improved. The compounding amount of the component (D) is not particularly limited, and is appropriately determined in the range of 0.01 to 50 parts by mass with respect to 100 parts by mass of the energy ray-curable polymer (A).

As a crosslinking agent (E), the polyfunctional compound which has the reactivity with the functional group which energy-beam-curable polymer (A) etc. have can be used. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, Reactive phenol resin etc. can be mentioned. The shear force described above can be adjusted by blending the crosslinking agent (E) into the energy ray curable adhesive.

The compounding amount of the crosslinking agent (E) is preferably 0.01 to 8 parts by mass, particularly preferably 0.04 to 5 parts by mass with respect to 100 parts by mass of the energy ray-curable polymer (A). Is more preferable, and 0.05 to 3.5 parts by mass is more preferable.

The polymerizable branched polymer (F) means a polymer having an energy ray polymerizable group and a branched structure. When the energy ray-curable adhesive contains a polymerizable branched polymer, transfer of the organic substance from the adhesive layer to the semiconductor wafer or semiconductor chip laminated on the adhesive sheet for stealth dicing can be suppressed, and also stealth In the step of individually picking up semiconductor chips from the pressure-sensitive adhesive sheet for dicing, it is possible to reduce the mechanical load that the semiconductor chips receive. Although it is not clear how the polymerizable branched polymer (F) contributes to such effects, the polymerizable branched polymer (F) has an interface with the semiconductor wafer or the semiconductor chip in the adhesive layer. It is believed that the polymer has a tendency to be present in the vicinity, or the polymerizable branched polymer (F) is irradiated with an energy ray to form an energy ray curable polymer (A) or an energy ray curable monomer and / or Polymerization with the oligomer (B) may be affected.

The specific structure such as the molecular weight of the polymerizable branched polymer (F), the degree of the branched structure, and the number of energy ray-polymerizable groups contained in one molecule is not particularly limited. As an example of a method of obtaining such a polymerizable branched polymer (F), first, a monomer having two or more radically polymerizable double bonds in the molecule, an active hydrogen group and one radically polymerizable A polymer having a branched structure is obtained by polymerizing a monomer having a double bond in the molecule and a monomer having one radically polymerizable double bond in the molecule. Next, the obtained polymer is reacted with a compound having a functional group capable of forming a bond by reacting with the active hydrogen group of the polymer and at least one radically polymerizable double bond in the molecule. Thus, the polymerizable branched polymer (F) can be obtained. As a commercial item of the polymerizable branched polymer (F), for example, “OD-007” manufactured by Nissan Chemical Industries, Ltd. can be used.

The weight average molecular weight (Mw) of the polymerizable branched polymer (F) is to appropriately suppress the interaction with the energy ray curable polymer (A) and the energy ray curable monomer and / or oligomer (B) From the viewpoint of facilitating the reaction, it is preferably 1,000 or more, and particularly preferably 3,000 or more. The weight average molecular weight (Mw) is preferably 100,000 or less, and particularly preferably 30,000 or less.

The content of the polymerizable branched polymer (F) in the pressure-sensitive adhesive layer is not particularly limited, but from the viewpoint of favorably achieving the above-mentioned effects of containing the polymerizable branched polymer (F), energy beam curing is usually performed. It is preferable that it is 0.01 mass part or more with respect to 100 mass parts of type polymers (A), and it is preferable that it is 0.1 mass part or more. Since the polymerizable branched polymer (F) has a branched structure, the above-mentioned effects can be favorably obtained even if the content in the pressure-sensitive adhesive layer is relatively small.

Depending on the type of the polymerizable branched polymer (F), the polymerizable branched polymer (F) may remain as particles on the contact surface of the semiconductor wafer or the semiconductor chip with the pressure-sensitive adhesive layer. It is preferable that the number of remaining particles is small, since these particles may reduce the reliability of the product provided with the semiconductor chip. Specifically, the number of particles having a particle diameter of 0.20 μm or more remaining on a silicon wafer as a semiconductor wafer is preferably less than 100, and particularly preferably 50 or less. From the viewpoint of facilitating satisfying the requirement for such particles, the content of the polymerizable branched polymer (F) is 3.0 parts by mass with respect to 100 parts by mass of the energy ray-curable polymer (A) The amount is preferably less than 2.5 parts by mass, particularly preferably 2.5 parts by mass or less, and more preferably 2.0 parts by mass or less.

Next, the case where the energy ray-curable adhesive is mainly composed of a mixture of a non-energy ray-curable polymer component and a monomer and / or oligomer having at least one energy ray-curable group will be described below. .

As the non-energy ray curable polymer component, for example, the same component as the acrylic copolymer (a1) described above can be used.

As the monomer and / or oligomer having at least one or more energy ray-curable groups, the same one as the component (B) described above can be selected. The compounding ratio of the non-energy ray curable polymer component to the monomer and / or oligomer having at least one energy ray curable group is at least one or more with respect to 100 parts by mass of the non energy ray curable polymer component. The amount is preferably 1 to 200 parts by mass, particularly preferably 60 to 160 parts by mass, of the monomer and / or oligomer having an energy ray-curable group.

Also in this case, the photopolymerization initiator (C) and the crosslinking agent (E) can be appropriately blended in the same manner as described above.

The thickness of the pressure-sensitive adhesive layer is not particularly limited as long as the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment can properly function in each step. Specifically, the thickness is preferably 1 to 50 μm, particularly preferably 3 to 40 μm, and further preferably 5 to 30 μm.

The pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment preferably has a storage elastic modulus at 23 ° C. of 1 to 5000 kPa, particularly preferably 3 to 3000 kPa, and further preferably 5 to 2500 kPa. Is preferred. When the storage elastic modulus at 23 ° C. of the pressure-sensitive adhesive layer is in the above range, the pressure-sensitive adhesive sheet for stealth dicing becomes easy to expand, and it becomes possible to divide the chip well. In addition, the measuring method of the said storage elastic modulus is as showing to the test example mentioned later.

2. Base Material The base material of the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment preferably has a storage elastic modulus at 23 ° C. of 10 MPa or more and 600 MPa or less. When the storage elastic modulus of the base material is in the above range when the shear force of the pressure-sensitive adhesive layer is in the above-described range, stealth dicing can be performed while suppressing deviation at the interface between the adhesive sheet for stealth dicing and the semiconductor wafer. As a result of the pressure-sensitive adhesive sheet being sufficiently stretched, the semiconductor wafer can be favorably divided into chips. In addition, the measuring method of the said storage elastic modulus is as showing to the test example mentioned later.

In addition, since the base material exhibits a predetermined rigidity when the storage elastic modulus is 10 MPa or more, the pressure-sensitive adhesive layer formed on a release sheet or the like can be transferred to the base material by transfer, efficiently for stealth dicing An adhesive sheet can be manufactured. Furthermore, the handling of the adhesive sheet for stealth dicing is also improved. On the other hand, a semiconductor wafer can be favorably supported by the adhesive sheet for stealth dicing with which the said storage elastic modulus is 600 Mpa or less with which the ring frame was mounted | worn.

From the above viewpoints, the lower limit value of the storage elastic modulus is more preferably 50 MPa or more, and particularly preferably 100 MPa or more. The upper limit value of the storage elastic modulus is more preferably 580 MPa or less, and particularly preferably 550 MPa or less.

When performing a modified layer forming step of irradiating a semiconductor wafer bonded to a pressure-sensitive adhesive sheet for stealth dicing with a laser beam through the pressure-sensitive adhesive sheet for stealth dicing, the base in the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment Preferably, the material exhibits excellent light transmittance to light of the wavelength of the laser light.

Moreover, when using an energy ray for hardening an adhesive layer, it is preferable that a base material has the light transmittance with respect to the said energy ray. The energy ray will be described later.

It is preferable that the base material in the adhesive sheet for stealth dicing which concerns on this embodiment is a thing containing the film (resin film) which has a resin-based material as a main material, and it is preferable to consist only of a resin film especially. Specific examples of the resin film include ethylene-vinyl acetate copolymer film; ethylene- (meth) acrylic acid copolymer film, ethylene-methyl (meth) acrylate copolymer film, and other ethylene- (meth) acrylic resins Ethylene copolymer films such as acid ester copolymer films; Polyolefin films such as polyethylene films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, ethylene-norbornene copolymer films, norbornene resin films; Polyvinyl chloride-based films such as vinyl films and vinyl chloride copolymer films; Polyester-based films such as polyethylene terephthalate films, polybutylene terephthalate films and polyethylene naphthalates Beam; and the like fluororesin film; (meth) acrylic acid ester copolymer film; polyurethane film; polyimide film; polystyrene films; polycarbonate films. Examples of polyethylene films include low density polyethylene (LDPE) films, linear low density polyethylene (LLDPE) films, high density polyethylene (HDPE) films, and the like. In addition, modified films such as these crosslinked films and ionomer films are also used. The substrate may be a film made of one of these, or a film made of a combination of two or more of these. In addition, it may be a laminated film of a multilayer structure in which a plurality of layers made of one or more of the materials described above are laminated. In this laminated film, the materials constituting each layer may be the same or different.

Among the above-mentioned films, polyolefin films such as ethylene-methacrylic acid copolymer film, polyethylene film and polypropylene film, ionomer films of such polyolefins, polyvinyl chloride films, polyurethane films, or (meth) acrylic acid ester co It is preferable to use a polymer film, a film made of linear low density polyethylene and polypropylene, and the like.

In the substrate, the above-mentioned film contains various additives such as a filler, a flame retardant, a plasticizer, an antistatic agent, a lubricant, an antioxidant, a coloring agent, an infrared absorber, an ultraviolet absorber, an ion scavenger and the like. It may be done. The content of these additives is not particularly limited, but it is preferable to set the range in which the substrate exhibits a desired function.

In the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment, when the substrate and the pressure-sensitive adhesive layer are directly laminated, the surface of the substrate on the pressure-sensitive adhesive layer side is a primer in order to enhance adhesion with the pressure-sensitive adhesive layer. Surface treatment such as treatment, corona treatment, plasma treatment may be applied.

The thickness of the substrate is not limited as long as it can function properly in the process in which the stealth dicing pressure-sensitive adhesive sheet is used. The thickness is usually preferably 20 to 450 μm, particularly preferably 25 to 250 μm, and further preferably 50 to 150 μm.

3. Release Sheet In order to protect the pressure-sensitive adhesive layer until the pressure-sensitive adhesive sheet for stealth dicing is used, on the surface of the pressure-sensitive adhesive sheet for stealth dicing according to this embodiment, on the opposite side to the substrate side. A release sheet may be laminated.

Although it does not specifically limit as a release sheet, For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethyl pentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polyethylene naphthalate film Polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene- (meth) acrylic acid copolymer film, ethylene- (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film And fluorine resin films and the like can be used. Moreover, you may use these crosslinked films. Furthermore, it may be a laminated film in which a plurality of these films are laminated.

It is preferable that the peeling process is performed to the peeling surface (The surface which has peeling property; especially the surface which contacts an adhesive layer) of the said peeling sheet. Examples of the release agent used for the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based and wax-based release agents.

The thickness of the release sheet is not particularly limited, and is usually about 20 μm to 100 μm.

4. Adhesive Force In the adhesive sheet for stealth dicing according to the present embodiment, the adhesive force to a silicon mirror wafer at 23 ° C. is preferably 1 N / 25 mm or more, and particularly preferably 2 N / 25 mm or more. The adhesive strength is preferably 30 N / 25 mm or less, and more preferably 29.5 N / 25 mm or less. When the adhesive strength at 23 ° C. is in the above range, when the pressure-sensitive adhesive sheet is expanded in the expanding step, it becomes easy to maintain the semiconductor wafer or the obtained semiconductor chip at a predetermined position, and division in the modified layer portion of the semiconductor wafer It is possible to do well. In addition, when an adhesive layer is comprised from energy-beam curable adhesive, the said adhesive force shall mean the adhesive force before energy-beam irradiation. Moreover, adhesive force says what was measured by the method mentioned later.

In the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment, when the pressure-sensitive adhesive layer is formed of an energy ray-curable pressure-sensitive adhesive, the adhesion to a silicon mirror wafer after energy ray irradiation at 23 ° C. is 10 mN / 25 mm or more Is preferably 20 mN / 25 mm or more. The adhesive strength is preferably 1000 mN / 25 mm or less, particularly preferably 900 mN / 25 mm or less. After singulation of the semiconductor wafer is completed, the adhesive force can be reduced to the above range by irradiating the adhesive sheet for stealth dicing with an energy beam, so that the obtained semiconductor chip can be easily picked up. It becomes. In addition, adhesive force says what was measured by the method mentioned later.

The adhesion at 23 ° C. and the adhesion after energy ray irradiation at 23 ° C. can be measured by the following method. First, a sheet for semiconductor processing is cut into a width of 25 mm, and the surface on the pressure-sensitive adhesive layer side is attached to a silicon mirror wafer. This sticking can be performed using a laminator (product name: RAD-3510F / 12, manufactured by Lintec Corporation) under the conditions of sticking speed 10 mm / s, wafer protrusion amount 20 μm and roller pressure 0.1 MPa. Then, the laminated body of the sheet | seat for semiconductor processings obtained and a silicon mirror wafer is left to stand for 20 minutes in 23 degreeC and the atmosphere of 50% RH. Here, in the case of measuring the adhesive force after energy ray irradiation at 23 ° C., after leaving for 20 minutes, an ultraviolet irradiation device (product name “RAD-2000 m / 12, manufactured by Lintec Co., Ltd.) is applied to the laminate. UV irradiation (illuminance 230 mW / cm ² , light quantity 190 mJ / cm ² ) is performed from the substrate side of the sheet under a nitrogen atmosphere. Following standing for 20 minutes or UV irradiation, a sheet with a peeling angle of 180 ° and a peeling speed of 300 mm / min using a universal tensile tester (product name “RTG-1225” manufactured by AMD) according to JIS Z0237 Is peeled off from the silicon mirror wafer, and the measured value is taken as the adhesion (mN / 25 mm).

5. The manufacturing method of the adhesive sheet for stealth dicing The manufacturing method of the adhesive sheet for stealth dicing which concerns on this embodiment is not specifically limited, A normal method can be used. As a first example of the manufacturing method, first, a pressure-sensitive adhesive composition containing a material of a pressure-sensitive adhesive layer, and, if desired, a coating composition containing a solvent or a dispersion medium, are prepared. Next, the coating composition is applied onto the release surface of the release sheet by a die coater, a curtain coater, a spray coater, a slit coater, a knife coater or the like to form a coating film. Furthermore, the pressure-sensitive adhesive layer is formed by drying the coating film. Then, the pressure-sensitive adhesive sheet for stealth dicing is obtained by pasting the pressure-sensitive adhesive layer on the release sheet and the substrate. The properties of the coating composition are not particularly limited as long as the composition can be coated. The component for forming an adhesive layer may be contained as a solute in the composition for coating, or may be contained as a dispersoid.

When the coating composition contains a crosslinking agent (E), the above-mentioned drying conditions (temperature, time, etc.) may be changed in order to form a crosslinked structure at a desired existing density, or heat treatment You may provide separately. In order to allow the crosslinking reaction to proceed sufficiently, usually, after laminating the pressure-sensitive adhesive layer on the substrate by the above method etc., the obtained pressure-sensitive adhesive sheet for stealth dicing is put in an environment of 23 ° C. and 50% relative humidity, for example. It cures by leaving it to stand for several days.

As a 2nd example of the manufacturing method of the adhesive sheet for stealth dicing which concerns on this embodiment, first, the said composition for coating is apply | coated to one side of a base material, and a coating film is formed. Next, the coating film is dried to form a laminate of the substrate and the pressure-sensitive adhesive layer. Furthermore, the exposed surface of the pressure-sensitive adhesive layer in the laminate is bonded to the release surface of the release sheet. Thereby, the adhesive sheet for stealth dicing in which the peeling sheet was laminated | stacked on the adhesive layer is obtained.

[Method of Manufacturing Semiconductor Device]
A method of manufacturing a semiconductor device according to an embodiment of the present invention includes a bonding step of bonding the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for stealth dicing (pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment) and the semiconductor wafer. A step of forming a modified layer inside the semiconductor wafer, and expanding a pressure-sensitive adhesive sheet for stealth dicing under a room temperature environment to cut the semiconductor wafer having the modified layer formed therein into individual chips. And an expanding step of separating.

In the said manufacturing method, a bonding process may be performed prior to a modification layer formation process, conversely, a modification layer formation process may be performed first before a bonding process. In the modified layer forming step in the former case, the semiconductor wafer bonded to the adhesive sheet for stealth dicing according to the present embodiment is irradiated with laser light. In the modification layer forming step in the latter case, for example, the semiconductor wafer bonded to another adhesive sheet (for example, a back grind sheet) is irradiated with a laser beam.

According to the method for manufacturing a semiconductor device according to the present embodiment, the adhesive sheet for stealth dicing described above is used at least in the expanding step, and therefore, it is difficult for the adhesive sheet for stealth dicing and the semiconductor wafer to deviate at the interface in the expanding step. Become. As a result, the force for pulling the semiconductor wafer in the peripheral direction, which is generated by the expansion of the adhesive sheet for stealth dicing, tends to be concentrated on the modified layer, and as a result, the semiconductor wafer is favorably divided in the modified layer. Therefore, even when the obtained chip size is small, the occurrence of problems such as division failure and chip breakage can be suppressed, and a chip that is favorably segmented can be obtained.

In the method of manufacturing a semiconductor device according to the present embodiment, the adhesive film (DAF, NCF, etc.) is formed on the surface of the semiconductor wafer bonded to the adhesive sheet for stealth dicing opposite to the adhesive sheet side for stealth dicing. The method may further comprise a laminating step of laminating According to the method of manufacturing a semiconductor device of this embodiment, the bonding film can be favorably divided by the expanding step.

Hereinafter, preferable specific examples of the method of manufacturing a semiconductor device according to an embodiment of the present invention will be described.

(1) Bonding process First, the bonding process which bonds the pressure-sensitive adhesive layer and the semiconductor wafer of the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment is performed. Usually, the surface on the adhesive layer side of the adhesive sheet for stealth dicing is mounted on one surface of the semiconductor wafer, but the present invention is not limited to this. In this bonding step, a ring frame is usually attached to a region on the outer peripheral side of the region to which the semiconductor wafer is attached on the adhesive layer side of the adhesive sheet for stealth dicing. In this case, in plan view, an area where the adhesive layer is exposed is present as a peripheral area between the ring frame and the semiconductor wafer.

(2) Laminating Step Next, a laminating step of laminating a bonding film may be performed on the surface of the semiconductor wafer bonded to the adhesive sheet for stealth dicing opposite to the adhesive sheet side for stealth dicing. This lamination is usually performed by heat lamination (thermal lamination). When the semiconductor wafer has an electrode on the surface, the adhesive film is usually laminated on the electrode side of the semiconductor wafer because the electrode is present on the surface of the semiconductor wafer opposite to the adhesive sheet side for stealth dicing.

The adhesive film may be any of DAF, NCF, etc., and usually has heat-sensitive adhesiveness. It does not specifically limit as a material, The film-like member formed from the adhesive composition containing heat-resistant resin materials, such as a polyimide resin, an epoxy resin, and a phenol resin, and a hardening accelerator is mentioned as a specific example.

(3) Modified Layer Forming Step Preferably, a modified layer forming step of forming a modified layer inside the semiconductor wafer is performed after the above bonding step or after the laminating step, but the modified layer is performed before these steps. You may perform a formation process. The modified layer forming step is usually performed by irradiating an infrared laser beam so as to be focused on a focal point set inside the semiconductor wafer (stealth dicing processing). The irradiation of the laser beam may be performed from any side of the semiconductor wafer. If the modified layer forming step is performed after the laminating step, it is preferable to irradiate a laser beam through the adhesive sheet for stealth dicing. Moreover, when performing a modification layer formation process between the said bonding process and the said lamination process, or when not performing the said lamination process, a laser beam is directly transmitted to a semiconductor wafer not via the adhesive sheet for stealth dicing. Irradiation is preferred.

(4) Expanding Step After the modifying layer forming step, an expanding step of cutting and separating the semiconductor wafer is performed by expanding the adhesive sheet for stealth dicing under a room temperature environment. As a result, on the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for stealth dicing, a semiconductor chip obtained by dividing the semiconductor wafer is attached. When an adhesive film is laminated on a semiconductor wafer, the adhesive film is also divided simultaneously with the division of the semiconductor wafer by an expanding step, and a chip with an adhesive layer is obtained.

Specific conditions in the expanding step are not limited. For example, the temperature at which the pressure-sensitive adhesive sheet for stealth dicing is expanded may be a general expand temperature, and as described above, the temperature is preferably 5 ° C. or higher, preferably 10 ° C. or higher. Furthermore, it is preferable that it is 15 degreeC or more. The temperature is preferably 45 ° C. or less, particularly preferably 40 ° C. or less, and more preferably 35 ° C. or less.

(5) Shrink step In the case where slack is generated in the peripheral region (region between the ring frame and the chip group in plan view) of the pressure-sensitive adhesive sheet for stealth dicing by the above expansion step, the shrink step of heating the peripheral region It is preferable to By heating the peripheral area of the stealth dicing pressure-sensitive adhesive sheet, the base material located in the peripheral area shrinks, and it becomes possible to reduce the amount of slack of the stealth dicing pressure-sensitive adhesive sheet generated in the expanding step. The heating method in the shrink process is not limited. Hot air may be blown, infrared radiation may be irradiated, or microwave may be irradiated.

(6) Pick-up step After the shrinking step in the case of performing the shrinking step, and after the expanding step in the case of not performing the shrinking step, the adhesive sheet for stealth dicing is individually adhered to the adhesive sheet for stealth dicing The chip is picked up from the chip to obtain a chip as a semiconductor device.

Here, when the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for stealth dicing is an energy ray-curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer is irradiated with energy rays at any stage after the bonding step and before the pickup step. It is preferable to cure the pressure-sensitive adhesive layer to reduce the adhesive strength. This makes it possible to pick up the chip more easily.

Examples of energy rays include ionizing radiation, that is, X-rays, ultraviolet rays, and electron beams. Among these, ultraviolet light which is relatively easy to introduce irradiation equipment is preferable.

When ultraviolet light is used as the ionizing radiation, near ultraviolet light including ultraviolet light having a wavelength of about 200 to 380 nm may be used because of easy handling. The amount of ultraviolet light may be appropriately selected according to the type of energy ray-curable adhesive contained in the adhesive layer and the thickness of the adhesive layer, and is usually about 50 to 500 mJ / cm ² and 100 to 450 mJ. / Cm ² is preferable, and 150 to 400 mJ / cm ² is more preferable. The ultraviolet illumination is usually 50 ~ 500mW / cm ² or so, preferably 100 ~ 450mW / cm ^2, more preferably 150 ~ 400mW / cm ^2. There is no restriction | limiting in particular as an ultraviolet-ray source, For example, a high pressure mercury lamp, a metal halide lamp, a light emitting diode (LED) etc. are used.

When an electron beam is used as the ionizing radiation, the accelerating voltage is appropriately selected according to the type of energy beam polymerizable group contained in the pressure sensitive adhesive layer, the type of energy beam polymerizable compound and the thickness of the pressure sensitive adhesive layer. It is preferable that the acceleration voltage is usually about 10 to 1000 kV. The irradiation dose may be appropriately selected according to the type of energy ray-curable adhesive contained in the adhesive layer and the thickness of the adhesive layer, and is usually selected in the range of 10 to 1000 krad. There is no restriction | limiting in particular as an electron beam source, For example, various electron beam accelerators, such as a Cockloft Wharton type, a bande graft type, a resonant transformer type, an insulation core transformer type, or a linear type, a dynamitron type, a high frequency type, are used. be able to.

By carrying out the above manufacturing method, a semiconductor device can be manufactured using the adhesive sheet for stealth dicing according to the present embodiment.

The embodiments described above are described to facilitate the understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents that fall within the technical scope of the present invention.

Hereinafter, the present invention will be more specifically described by way of examples and the like, but the scope of the present invention is not limited to these examples and the like.

Example 1
(1) Preparation of adhesive composition Acrylic copolymer obtained by reacting 2-ethylhexyl acrylate / isobornyl acrylate / 2-hydroxyethyl acrylate = 42/30/28 (mass ratio), and 2 80 mol% of methacryloyloxyethyl isocyanate (MOI) was reacted with hydroxyethyl acrylate to obtain an energy ray-curable polymer (Mw: 400,000).

100 parts by mass of the obtained energy ray-curable polymer, 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name “IRGACURE 184”) as a photopolymerization initiator, and tolylene diisocyanate as a crosslinking agent A system crosslinking agent (made by Toyo Ink Co., Ltd., product name "CORONATE L") and 1.07 parts by mass were mixed in a solvent to obtain a pressure-sensitive adhesive composition.

(2) Production of Pressure-Sensitive Adhesive Sheet for Stealth Dicing The above-mentioned pressure-sensitive adhesive composition was applied onto the release surface of a release sheet (manufactured by LINTEC Corporation, product name “SP-PET 3811”). Subsequently, drying by heating was performed, and the coating film of the pressure-sensitive adhesive composition was used as a pressure-sensitive adhesive layer. The thickness of the pressure-sensitive adhesive layer was 10 μm. Thereafter, the adhesive layer on the release sheet obtained, and an ethylene-methacrylic acid copolymer (EMAA) film (thickness: 80 μm, surface tension of the corona-treated surface: 54 mN) of which one surface is corona-treated as a substrate A pressure-sensitive adhesive sheet for stealth dicing was obtained by pasting with a corona-treated surface of / m).

[Example 3]
An acrylic copolymer obtained by reacting 2-ethylhexyl acrylate / methyl methacrylate / 2-hydroxyethyl acrylate = 42/30/28 (mass ratio) and 80 mol% relative to the 2-hydroxyethyl acrylate Methacryloyloxyethyl isocyanate (MOI) was reacted to obtain an energy ray-curable polymer (Mw: 400,000).

100 parts by mass of the obtained energy ray-curable polymer, 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name “IRGACURE 184”) as a photopolymerization initiator, and tolylene diisocyanate as a crosslinking agent A system crosslinking agent (made by Toyo Ink Co., Ltd., product name "CORONATE L") and 1.07 parts by mass were mixed in a solvent to obtain a pressure-sensitive adhesive composition. A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that the obtained pressure-sensitive adhesive composition was used.

[Example 3]
Acrylic copolymer obtained by reacting butyl acrylate / methyl methacrylate / 2-hydroxyethyl acrylate = 42/30/28 (mass ratio) and 80 mol% methacryloyloxy with respect to the 2-hydroxyethyl acrylate It was reacted with ethyl isocyanate (MOI) to obtain an energy ray-curable polymer (Mw: 400,000).

100 parts by mass of the obtained energy ray-curable polymer, 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name “IRGACURE 184”) as a photopolymerization initiator, and tolylene diisocyanate as a crosslinking agent A system crosslinking agent (made by Toyo Ink Co., Ltd., product name "CORONATE L") and 1.07 parts by mass were mixed in a solvent to obtain a pressure-sensitive adhesive composition. A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that the obtained pressure-sensitive adhesive composition was used.

Example 4
Acrylic copolymer obtained by reacting butyl acrylate / methyl methacrylate / 2-hydroxyethyl acrylate = 42/30/28 (mass ratio) and 70% by mole of methacryloyloxy with respect to the 2-hydroxyethyl acrylate It was reacted with ethyl isocyanate (MOI) to obtain an energy ray-curable polymer (Mw: 400,000).

100 parts by mass of the obtained energy ray-curable polymer, 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name “IRGACURE 184”) as a photopolymerization initiator, and tolylene diisocyanate as a crosslinking agent An adhesive composition was obtained by mixing 0.43 parts by mass of a crosslinking agent (manufactured by Toyo Ink Co., Ltd., product name "Coronato L") in a solvent. A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that the obtained pressure-sensitive adhesive composition was used.

[Example 5]
An acrylic copolymer obtained by reacting lauryl acrylate / methyl methacrylate / 2-hydroxyethyl acrylate = 42/30/28 (mass ratio), and 80 mol% of methacryloyloxy with respect to 2-hydroxyethyl acrylate It was reacted with ethyl isocyanate (MOI) to obtain an energy ray-curable polymer (Mw: 400,000).

100 parts by mass of the obtained energy ray-curable polymer, 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name “IRGACURE 184”) as a photopolymerization initiator, and tolylene diisocyanate as a crosslinking agent A system crosslinking agent (made by Toyo Ink Co., Ltd., product name "CORONATE L") and 1.07 parts by mass were mixed in a solvent to obtain a pressure-sensitive adhesive composition. A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that the obtained pressure-sensitive adhesive composition was used.

Comparative Example 1
Acrylic copolymer obtained by reacting butyl acrylate / methyl methacrylate / 2-hydroxyethyl acrylate = 80/5/15 (mass ratio), and 80 mol% of methacryloyloxy with respect to 2-hydroxyethyl acrylate An energy ray-curable polymer was obtained by reacting ethyl isocyanate (MOI). The weight-average molecular weight (Mw) of this energy ray-curable polymer was 400,000.

100 parts by mass of the obtained energy ray-curable polymer (in terms of solid content; the same applies hereinafter) and 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name “IRGACURE 184”) as a photopolymerization initiator 3 A mass part and 0.49 mass parts of tolylene diisocyanate type crosslinking agent (made by Nippon Polyurethane Industry Co., Ltd., product name "Coronato L") as a crosslinking agent were mixed in a solvent to obtain a pressure-sensitive adhesive composition. A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that the obtained pressure-sensitive adhesive composition was used.

Comparative Example 2
An acrylic copolymer obtained by reacting 2-ethylhexyl acrylate / vinyl acetate / 2-hydroxyethyl acrylate = 60/20/20 (mass ratio), and 80 mol% relative to the 2-hydroxyethyl acrylate Methacryloyloxyethyl isocyanate (MOI) was reacted to obtain an energy ray-curable polymer (Mw: 400,000).

100 parts by mass of the obtained energy ray-curable polymer, 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name “IRGACURE 184”) as a photopolymerization initiator, and tolylene diisocyanate as a crosslinking agent An adhesive composition was obtained by mixing 0.31 parts by mass of a crosslinker (product name: Coronate L, manufactured by Toyo Ink Co., Ltd.) with a solvent. A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that the obtained pressure-sensitive adhesive composition was used.

Comparative Example 3
Acrylic copolymer obtained by reacting butyl acrylate / methyl methacrylate / 2-hydroxyethyl acrylate = 62/10/28 (mass ratio), and 80 mol% of methacryloyloxy relative to 2-hydroxyethyl acrylate It was reacted with ethyl isocyanate (MOI) to obtain an energy ray-curable polymer (Mw: 400,000).

100 parts by mass of the obtained energy ray-curable polymer, 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name “IRGACURE 184”) as a photopolymerization initiator, and tolylene diisocyanate as a crosslinking agent A system crosslinking agent (made by Toyo Ink Co., Ltd., product name "CORONATE L") and 1.61 parts by mass were mixed in a solvent to obtain an adhesive composition. A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that the obtained pressure-sensitive adhesive composition was used.

[Test Example 1] (Measurement of Shear Force)
The backing of the pressure-sensitive adhesive sheet for stealth dicing obtained in Examples and Comparative Examples, using the instant adhesive (product name "Aron Alpha" manufactured by Toagosei Co., Ltd.) A polyethylene terephthalate film (thickness: 100 μm) as a material was adhered to obtain a laminate.

The obtained laminate was cut into a length of 50 mm and a width of 30 mm under an environment of a temperature of 23 ° C. and a relative humidity of 50%, and then the release sheet was peeled off from the pressure-sensitive adhesive layer to obtain a sample. This sample was attached to the mirror surface of a silicon mirror wafer (thickness: 350 μm) via a pressure-sensitive adhesive layer under an environment of a temperature of 23 ° C. and a relative humidity of 50%. At this time, a 2 kg roller was reciprocated once with respect to the sample to apply a load, and the sample was pasted so that a 3 mm portion in the longitudinal direction of the sample was in close contact with the silicon wafer. Next, on the silicon mirror wafer, only the sample was cut with a cutter so that the width of the sample was 20 mm, and the unnecessary cut piece of the sample was peeled off from the silicon mirror wafer. Thereby, as shown in FIG. 1 and FIG. 2, the test object obtained by sticking a sample and a silicon mirror wafer in the area | region of 20 mm x 3 mm (60 mm < ² >) was obtained. In FIG. 1 and FIG. 2, reference numeral 1 indicates a backing adhesive sheet for stealth dicing (sample), reference numeral 2 indicates a silicon mirror wafer, reference numeral 11 indicates a base material, reference numeral 12 indicates an adhesive layer, and reference numeral 13 indicates a backing material. Indicates

Twenty minutes after application, a tensile test was performed using an autograph (product name "SDT-203NB-50R3" manufactured by Imada Seisakusho, Ltd., under the conditions of a tensile speed of 1 mm / min. Under an environment of 23 ° C.). , Shear force (N / (3 mm × 20 mm)) was measured. The results are shown in Table 1.

[Test Example 2] (Measurement of storage elastic modulus of base material)
The storage elastic modulus (MPa) of the substrate at 23 ° C. was measured for the substrates used in Examples and Comparative Examples under the following apparatus and conditions. The results are shown in Table 1.
Measuring device: manufactured by TA Instruments, dynamic elastic modulus measuring device "DMA Q800"
Test start temperature: 0 ° C
Test end temperature: 200 ° C
Heating rate: 3 ° C / min Frequency: 11 Hz
Amplitude: 20 μm

[Test Example 3] (Measurement of storage modulus of adhesive layer)
The pressure-sensitive adhesive composition used in Examples and Comparative Examples is applied to the release surface of the release sheet to form a pressure-sensitive adhesive layer, and the release surface of the release sheet separately prepared is crimped to the exposed pressure-sensitive adhesive layer. , A release sheet / pressure-sensitive adhesive layer / a release sheet was produced. The release sheet was peeled off from the pressure-sensitive adhesive sheet, and a plurality of pressure-sensitive adhesive layers were laminated so as to have a thickness of 200 μm. A 30 mm × 4 mm rectangle (thickness: 200 μm) was punched out of the obtained laminate of pressure-sensitive adhesive layers, and this was used as a measurement sample. The storage elastic modulus (kPa) of the pressure-sensitive adhesive layer at 23 ° C. was measured for the measurement sample under the following apparatus and conditions. The results are shown in Table 1.
Measuring device: manufactured by TA Instruments, dynamic elastic modulus measuring device "DMA Q800"
Distance between measurements: 20 mm
Test start temperature: -30 ° C
Test end temperature: 120 ° C
Heating rate: 3 ° C / min Frequency: 11 Hz
Amplitude: 20 μm

[Test Example 4] (Evaluation of divisibility)
A mirror surface of a 6 inch ring frame and a 6 inch silicon mirror wafer (thickness: 150 μm) was attached to the adhesive layer of the adhesive sheet for stealth dicing obtained in Examples and Comparative Examples. Then, using a stealth dicing apparatus (manufactured by Disco, product name “DFL 7360”), a laser is irradiated from the opposite side of the adhesive sheet for stealth dicing in a 6 inch silicon mirror wafer under the following conditions: The modified layer was formed in a 6 inch silicon mirror wafer. Laser irradiation at this time was performed in two ways so that the size of the obtained chip was 8 mm square and 4 mm square, respectively.
<Conditions of irradiation>
Irradiation height: 100 μm from the tape side
Frequency: 90Hz
Output: 0.25W
Machining speed: 360 mm / sec

After that, using the Expand device (product name “ME-300B” manufactured by JCM), the above workpiece was expanded at a withdrawal speed of 100 mm / sec and a withdrawal amount of 10 mm under an environment of 23 ° C. Next, the number of chips that were well separated at the position of the reforming layer and completely separated from surrounding chips was counted, and the ratio (%) to the total number of chips theoretically obtained was calculated. And division property was evaluated based on the following criteria. The results are shown in Table 1.
○: The above ratio is 100%.
Δ: The above ratio is less than 100% and 80% or more.
X: The above ratio is less than 80%.

As can be seen from Table 1, the adhesive sheet for stealth dicing obtained in the example can divide the wafer on which the modified layer is formed well by expanding, and in particular, the chip size is 8 mm square or Even when it was as small as 4 mm square, it showed excellent splittability.

The adhesive sheet for stealth dicing which concerns on this invention is used suitably for the manufacturing method of the semiconductor device which performs the expand process at room temperature.

1 ... Adhesive sheet for stealth dicing with backing material (sample)
11: Base material 12: adhesive layer 13: backing material 2: silicon mirror wafer

Claims (7)

1. At least an adhesive sheet for stealth dicing, which is used to cut and separate a semiconductor wafer having a modification layer formed therein into individual chips under a room temperature environment,
   A substrate and an adhesive layer laminated on one side of the substrate,
   The shear force at 23 ° C. of the interface between the pressure-sensitive adhesive layer and the silicon wafer is 70 N / (3 mm × 20 mm) or more when the pressure-sensitive adhesive sheet for stealth dicing is attached to the silicon wafer via the pressure-sensitive adhesive layer. And a pressure-sensitive adhesive sheet for stealth dicing characterized by being 250 N / (3 mm × 20 mm) or less.
2. The adhesive sheet for stealth dicing according to claim 1, wherein the chip has a minimum side length of 2 mm or more and 30 mm or less.
3. The adhesive sheet for stealth dicing according to claim 1, wherein the semiconductor wafer has a thickness of 10 μm or more and 1000 μm or less.
4. The stealth dicing pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer is composed of an energy ray-curable pressure-sensitive adhesive.
5. The adhesive sheet for stealth dicing according to any one of claims 1 to 4, wherein a storage elastic modulus at 23 ° C of the base material is 10 MPa or more and 600 MPa or less.
6. A bonding step of bonding the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for stealth dicing according to any one of claims 1 to 5 and a semiconductor wafer;
   A modified layer forming step of forming a modified layer inside the semiconductor wafer;
   An expanding step of expanding the adhesive sheet for stealth dicing under a room temperature environment and cutting and separating the semiconductor wafer having the modified layer formed therein into individual chips; Method.
7. 7. The method according to claim 6, further comprising a laminating step of laminating a bonding film on the surface of the semiconductor wafer bonded to the adhesive sheet for stealth dicing opposite to the adhesive sheet side for stealth dicing. The manufacturing method of the described semiconductor device.

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