KR102382843B1 - Stealth dicing adhesive sheet and method for manufacturing semiconductor device using same - Google Patents

Abstract

A pressure-sensitive adhesive sheet for stealth dicing having a base material and an pressure-sensitive adhesive layer laminated on one side of the base material, wherein the base material has a tensile modulus of 50 MPa or more and 450 MPa or less at 23 ° C. The pressure-sensitive adhesive layer is composed of an energy ray-curable pressure-sensitive adhesive comprising an acrylic copolymer comprising n-butyl acrylate, 2-hydroxyethyl acrylate, and (meth)acrylic acid alkylester having an alkyl group having 2 or less carbon atoms as constituent monomers. Adhesive sheet for dicing. Such an adhesive sheet for stealth dicing is excellent in solvent resistance and heat shrink property.

Description

Stealth dicing adhesive sheet and method for manufacturing semiconductor device using same

The present invention relates to an adhesive sheet for stealth dicing (registered trademark), and preferably to an adhesive sheet for stealth dicing in which a semiconductor wafer having a through electrode is used as a workpiece.

In response to increase in capacity and high functionality of electronic circuits, development of multilayer circuits in which a plurality of semiconductor chips are three-dimensionally stacked is being developed. In such a multilayer circuit, conventionally, conductive connection of semiconductor chips has been generally performed by wire bonding. However, in response to the recent need for miniaturization and high functionality, wire bonding is not performed and the semiconductor chip is penetrated from the circuit formation surface to the back surface. An effective method has been developed as an effective method in which electrodes TSV are provided to directly electrically connect the upper and lower chips. As a method for manufacturing a chip with a through electrode, for example, a through hole is provided at a predetermined position on a semiconductor wafer by plasma or the like, and a conductor such as copper flows into the through hole, followed by etching or the like. Thus, the method of providing a circuit and a through electrode on the surface of a semiconductor wafer, etc. are mentioned. At this time, the wafer is heated.

Since such ultra-thin wafers and TSV wafers are extremely fragile, they may be damaged in the backside grinding (backgrinding) process and subsequent processing and transfer processes. For this reason, during these steps, the wafer is held on a hard support such as glass with an adhesive interposed therebetween. As this adhesive, general-purpose adhesives, such as an acrylic type, an epoxy type, an inorganic type, were used in some cases. Moreover, when a wafer is exposed to high temperature during a processing process, the wafer and a hard support body are joined by the adhesive agent with high heat resistance, for example, a polyimide adhesive.

After the backside grinding and processing of the wafer is completed, the wafer is electrodeposited on a dicing sheet from a hard support, the periphery of the dicing sheet is fixed by a ring frame, and then the wafer is cut and chipped for each circuit, Thereafter, chips are picked up from the dicing sheet. When the wafer is electrodeposited from the rigid support to the dicing sheet, the wafer-side surface of the rigid support to which the wafer is fixed is adhered on the dicing sheet, the rigid support is peeled from the wafer, and the wafer is placed on the dicing sheet electrodeposited on When peeling a hard support body, heat sliding which softens an adhesive agent by heating and slides a hard support body, or laser beam irradiation decomposes|disassembles an adhesive agent and peels a hard support body. However, an adhesive agent and its decomposition product may remain on the wafer surface after peeling the hard support body.

In order to wash off the remaining adhesive residue, the wafer fixed on the dicing sheet may be washed with an organic solvent. In this cleaning, for example, a laminate of a dicing sheet and a wafer is immersed in an organic solvent, or a frame slightly larger than the wafer is arranged to surround the wafer, and an organic solvent is introduced into the frame to wash the wafer. is cleaning Moreover, when peeling a wafer from a hard support body, immersing a wafer and a hard support body in an organic solvent other than the above-mentioned method is also performed.

At the time of the said washing|cleaning, the adhesive layer of a dicing sheet may swell or melt|dissolve with an organic solvent, adhesive force may be lost, and a wafer and a ring frame may fall off from a dicing sheet. Moreover, wrinkles arise in the base material of a dicing sheet by the organic solvent, and when it sticks to a thin wafer like a TSV wafer, there existed a problem that the said wafer would crack.

In Patent Document 1, one of the problems is that the adhesive does not dissolve and contaminate the semiconductor element even when the cleaning liquid comes into contact, and a pressure-sensitive adhesive containing a base resin film and a silicone acrylate or a fluorinated oligomer in a predetermined ratio. An adhesive tape for semiconductor processing having a layer is disclosed.

In addition, in Patent Document 2, even when in contact with an organic solvent, the adhesive force of the pressure-sensitive adhesive layer can be maintained, and wrinkles do not occur on the substrate, and it is an object to provide a pressure-sensitive adhesive sheet for processing an electronic component having excellent pick-up properties of chips, Disclosed is an adhesive sheet for processing an electronic component comprising a substrate containing polybutylene terephthalate and an adhesive layer containing a predetermined energy ray-curable polymer.

Japanese Patent No. 5607847 Japanese Patent Laid-Open No. 2015-72997

When picking up the semiconductor chip obtained by the dicing mentioned above, expanding the adhesive sheet to which the said semiconductor chip was affixed is performed. Thereby, semiconductor chips are separated from each other, and it becomes easy to pick up a semiconductor chip. In such expanding, the region in the adhesive sheet to which the semiconductor chip is affixed is supported on the stage from the surface opposite to the surface to which the semiconductor chip is affixed, and is affixed to the periphery of the adhesive sheet with respect to the height of the stage. This is done by relatively lowering the height of the ring frame.

In addition, when performing the said expansion, after the dicing sheet is sucked by the suction table while maintaining the expanded state, between the area|region to which the ring frame in the dicing sheet was affixed and the area|region to which the semiconductor chip was stuck. In some cases, a treatment (heat shrink) of heating and shrinking the region of Due to the shrinkage, a force is generated in the dicing sheet to stretch the region where the semiconductor chip is pasted in the peripheral direction, and as a result, even after the dicing sheet is released from the suction by the suction table, the semiconductor chips are separated from each other. You can maintain a detached state.

By the way, as a dicing method, a dicing method using a dicing blade, a dicing method (stealth dicing), etc. including forming a modified portion by irradiation with laser light and dividing the modified portion at the time of expansion this exists Of these, in the method using a dicing blade, since the portion in contact with the dicing blade in the semiconductor wafer is cut, the obtained semiconductor chips are separated only by the cut width, even in a state in which expansion is not performed. it will be On the other hand, in stealth dicing, a modified part is formed in a semiconductor wafer by irradiation of a laser beam, and a some semiconductor chip is obtained by dividing|segmenting a semiconductor wafer in the said modified part. Therefore, in a semiconductor wafer, the above-mentioned part to be cut does not generate|occur|produce, and the semiconductor chips obtained will almost come into contact in the state which does not expand.

Therefore, when performing the above-described heat shrink, it is more difficult to keep the semiconductor chips widely spaced apart from each other in the case of stealth dicing than in dicing using a dicing blade. It becomes easy to cause problems.

Therefore, while being used for cleaning with the above-mentioned organic solvent, in the adhesive sheet used also for stealth dicing, while it has solvent resistance, the adhesive sheet shrinks favorably by a heat shrink, and semiconductor chips are good In particular, it is required to be able to keep it in a well-spaced state (hereinafter referred to as "excellent heat shrinkability" in some cases).

However, in the adhesive tape for semiconductor processing disclosed by patent document 1, although an adhesive layer exhibits predetermined solvent resistance, the material which cannot exhibit sufficient solvent resistance as a base material is used, Therefore, at the time of a washing|cleaning process, a base material is solvent When it contacted, there existed a problem that wrinkles generate|occur|produced in the adhesive tape for semiconductor processing, and a semiconductor wafer will break.

Moreover, in the adhesive sheet for electronic component processing disclosed in patent document 2, since the polybutylene terephthalate film which does not easily generate|occur|produce shrinkage by heating is used as a base material, between semiconductor chips is favorable by heat shrink. It was difficult to keep it in a detached state.

This invention was made in view of such a real situation, and an object of this invention is to provide the adhesive sheet for stealth dicing excellent in solvent resistance and heat shrink property.

In order to achieve the above object, first, the present invention is an adhesive sheet for stealth dicing comprising a substrate and an adhesive layer laminated on one side of the substrate, wherein the substrate has a tensile modulus of elasticity at 23°C Energy containing an acrylic copolymer comprising 50 MPa or more and 450 MPa or less, and wherein the pressure-sensitive adhesive layer contains, as constituent monomers, n-butyl acrylate, 2-hydroxyethyl acrylate, and (meth)acrylic acid alkyl ester having an alkyl group having 2 or less carbon atoms. It provides an adhesive sheet for stealth dicing, characterized in that it is composed of a precurable adhesive (Invention 1).

The adhesive sheet for stealth dicing which concerns on the said invention (invention 1) is excellent in heat shrink property because the tensile elasticity modulus in 23 degreeC of a base material is the said range. Moreover, excellent solvent resistance is exhibited by an adhesive layer being comprised with the energy-beam curable adhesive mentioned above. Since such an adhesive layer is laminated on one side of the substrate, even when the solvent is in contact with the surface on the side of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet for stealth dicing, the contact between the substrate and the solvent is blocked by the pressure-sensitive adhesive layer. , the occurrence of wrinkles in the substrate and the occurrence of cracks in the workpiece resulting therefrom are suppressed.

In the invention (invention 1), the content of 2-hydroxyethyl acrylate in all the monomers constituting the main chain of the acrylic copolymer is 5% by mass or more and 40% by mass or less, and the acrylic copolymer is It is preferable that content of the (meth)acrylic-acid alkylester whose carbon number of the said alkyl group in all the monomers which comprises the main chain is 5 mass % or more and 40 mass % or less (invention 2).

In the above invention (Inventions 1 and 2), the content of the n-butyl acrylate in the content of the (meth)acrylic acid alkylester having 2 or less carbon atoms in the alkyl group in all the monomers constituting the main chain of the acrylic copolymer The mass ratio to is 0.08 or more and 1.0 or less, and in all the monomers constituting the main chain of the acrylic copolymer, the content of the (meth)acrylic acid alkylester having 2 or less carbon atoms in the alkyl group, the acrylic acid 2-hydroxy It is preferable that mass ratio with respect to content of ethyl is 0.3 or more and 4.0 or less (Invention 3).

In the said invention (invention 1-3), it is preferable that the glass transition temperature (Tg) of the said acrylic copolymer is -50 degreeC or more and 0 degreeC or less (invention 4).

In the above inventions (Inventions 1 to 4), it is preferable that the dissolution parameters (SP values) of the acrylic copolymer are 9.06 or more and 10 or less (Invention 5).

In the above inventions (inventions 1 to 5), the (meth)acrylic acid alkylester having 2 or less carbon atoms in the alkyl group is preferably methyl methacrylate, methyl acrylate or ethyl acrylate (Invention 6).

In the above inventions (Inventions 1 to 6), the substrate is preferably at least one selected from random polypropylene, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ethylene-(meth)acrylic acid copolymer. do (invention 7).

In the above inventions (Inventions 1 to 7), it is preferable to use a semiconductor wafer having a through electrode as a workpiece (Invention 8).

In the said invention (invention 1-8), it is preferable to use for the manufacturing method of a semiconductor device provided with the process of washing|cleaning the workpiece laminated|stacked on the said adhesive sheet for stealth dicing using a solvent (invention 9) .

In the said invention (Inventions 1-9), manufacture of the semiconductor device provided with the process of shrink|contracting by heating the area|region in which the said work piece is not laminated|stacked in the said adhesive sheet for stealth dicing on which the workpiece|work was laminated|stacked. It is preferably used in the method (Invention 10).

The adhesive sheet for stealth dicing which concerns on this invention is excellent in solvent resistance and heat shrink property.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

The adhesive sheet for stealth dicing which concerns on this embodiment is equipped with the base material, and the adhesive layer laminated|stacked on the single side|surface side in a base material.

In the adhesive sheet for stealth dicing which concerns on this embodiment, the tensile elasticity modulus in 23 degreeC of a base material is 50 Mpa or more and 450 Mpa or less. Since the said base material shrinks favorably when heated, the adhesive sheet for stealth dicing provided with the said base material becomes a thing excellent in heat shrink property.

Further, in the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment, the pressure-sensitive adhesive layer is an acryl-based acrylic acid containing n-butyl acrylate, 2-hydroxyethyl acrylate, and (meth)acrylic acid alkylester having an alkyl group having 2 or less carbon atoms as constituent monomers. It is composed of an energy ray-curable pressure-sensitive adhesive containing a copolymer. Since the said adhesive shows the outstanding solvent resistance, when an adhesive layer contacts an organic solvent, while it is suppressed that the component in an adhesive layer elutes to an organic solvent and contaminates a workpiece, the adhesive sheet for stealth dicing with respect to a workpiece It is suppressed that the adhesive force of a fall is suppressed.

Moreover, when the organic solvent contacts the side of the adhesive layer in the adhesive sheet for stealth dicing because the adhesive layer which has the above solvent resistance is laminated|stacked on the single side|surface side of a base material, an organic solvent by an adhesive layer is blocked from contacting the substrate. Thereby, generation|occurrence|production of the wrinkle in the base material by contact with an organic solvent is prevented, As a result, it is suppressed that the workpiece|work affixed on the adhesive sheet for stealth dicing is broken.

Moreover, as a work piece by which the adhesive sheet for stealth dicing which concerns on this embodiment is used, semiconductor members, such as a semiconductor wafer and a semiconductor package, glass members, such as a glass plate, etc. are mentioned, for example. The semiconductor wafer may be a semiconductor wafer (TSV wafer) having a through electrode. As described above, in the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment, the generation of wrinkles due to contact with the organic solvent is suppressed, so even when the thickness of the workpiece is thin, cracking of the workpiece is reduced. is suppressed For this reason, as a work piece in which the adhesive sheet for stealth dicing is used, the semiconductor wafer which has a generally very thin thickness and has a through electrode is suitable.

1. Structural members of the adhesive sheet for stealth dicing

(1) description

In the adhesive sheet for stealth dicing which concerns on this embodiment, it is 450 MPa or less, it is preferable that it is 400 MPa or less, and, as for the tensile elasticity modulus in 23 degreeC of a base material, it is especially preferable that it is 300 MPa or less. Moreover, it is 50 MPa or more, and, as for the said tensile elasticity modulus, it is preferable that it is 70 MPa or more, and it is especially preferable that it is 100 MPa or more. When the tensile modulus exceeds 450 MPa, the base material cannot be sufficiently expanded and contracted even when heated. cannot be maintained in a sufficiently separated state. On the other hand, when the said tensile elasticity modulus is less than 50 MPa, a base material cannot have sufficient elasticity, but the workability and handling property of the adhesive sheet for stealth dicing fall. In addition, the detail of the measuring method of the said tensile elasticity modulus is as having described in the test example mentioned later.

As a material of a base material, while exhibiting the said tensile elasticity modulus, it exhibits the desired function in the use process of the adhesive sheet for stealth dicing, Preferably, it has favorable permeability with respect to the energy ray irradiated for hardening of an adhesive layer. It is not specifically limited as long as it exhibits. For example, the substrate is preferably a resin film mainly composed of a resin material, and specific examples thereof include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, and ethylene-norbornene. Polyolefin-type films, such as a copolymer film and a norbornene resin film; ethylene-based copolymer films such as ethylene-(meth)acrylic acid copolymer films, ethylene-(meth)methyl acrylate copolymer films, and other ethylene-(meth)acrylic acid ester copolymer films; ethylene-vinyl acetate copolymer film; polyvinyl chloride-based films such as polyvinyl chloride films and vinyl chloride copolymer films; (meth)acrylic acid ester copolymer film; polyurethane film; polystyrene film; A fluororesin film etc. are mentioned. In the polyolefin-based film, the polyolefin may be a block copolymer or a random copolymer. Examples of the polyethylene film include a low-density polyethylene (LDPE) film, a linear low-density polyethylene (LLDPE) film, and a high-density polyethylene (HDPE) film. In addition, these crosslinked films and modified films such as ionomer films are also used. In addition, the laminated|multilayer film by which the above-mentioned film is laminated|stacked may be sufficient as a base material. In this laminated|multilayer film, the same type may be sufficient as the material which comprises each layer, and different types may be sufficient as it. In addition, "(meth)acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same is true for other similar terms.

As the substrate, from the viewpoint of being easy to exhibit the above-mentioned tensile modulus among the above films, a low-density polyethylene (LDPE) film, a linear low-density polyethylene (LLDPE) film, a polypropylene (random polypropylene) film of a random copolymer, or ethylene-meta It is preferred to use a acrylic acid copolymer film.

The base material may contain various additives such as a flame retardant, a plasticizer, an antistatic agent, a lubricant, an antioxidant, a colorant, an infrared absorber, and an ion trapping agent. Although it does not specifically limit as content of these additives, It is preferable to set it as the range in which a base material exhibits a desired function.

The surface on which the pressure-sensitive adhesive layer of the base material is laminated may be subjected to surface treatment such as a primer treatment, a corona treatment, and a plasma treatment, in order to improve adhesion with the pressure-sensitive adhesive layer.

It is preferable that it is 450 micrometers or less, and, as for the thickness of a base material, it is especially preferable that it is 400 micrometers or less, and it is more preferable that it is 350 micrometers or less. Moreover, it is preferable that the said thickness is 20 micrometers or more, It is especially preferable that it is 25 micrometers or more, It is more preferable that it is 50 micrometers or more. When the thickness of the base material is 450 µm or less, the base material is easily heat-shrinked, and it becomes possible to satisfactorily separate and hold the semiconductor chips and glass chips. Moreover, when the thickness of a base material is 20 micrometers or more, a base material becomes what has favorable elasticity, and it becomes possible for the adhesive sheet for stealth dicing to support a workpiece effectively.

(2) adhesive layer

In the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment, the pressure-sensitive adhesive layer includes, as constituent monomers, n-butyl acrylate, 2-hydroxyethyl acrylate, and (meth)acrylic acid alkylester having an alkyl group having 2 or less carbon atoms. It is comprised from the energy-beam curable adhesive containing a coal (it may be called "acrylic copolymer (a1)" hereafter). When an adhesive layer is comprised with the adhesive mentioned above, it will exhibit the outstanding solvent resistance.

Examples of the (meth)acrylic acid alkyl ester having 2 or less carbon atoms in the alkyl group contained as a constituent monomer in the acrylic copolymer (a1) include methyl methacrylate, methyl acrylate, ethyl methacrylate and ethyl acrylate, and these Among them, from the viewpoint of exhibiting excellent solvent resistance, the (meth)acrylic acid alkyl ester having 2 or less carbon atoms in the alkyl group is preferably methyl methacrylate, methyl acrylate, or ethyl acrylate.

The acrylic copolymer (a1) may contain, as constituent monomers, monomers other than n-butyl acrylate, 2-hydroxyethyl acrylate, and (meth)acrylic acid alkylester having an alkyl group having 2 or less carbon atoms.

For example, the acrylic copolymer (a1) may further contain, as a constituent monomer, a functional group-containing monomer other than 2-hydroxyethyl acrylate. It is preferable that such a functional group containing monomer is a monomer which has a polymerizable double bond and functional groups, such as a hydroxyl group, a carboxy group, an amino group, a substituted amino group, and an epoxy group, in a molecule|numerator.

Examples of the monomer containing a hydroxyl group in the molecule include 2-hydroxyethyl methacrylate, 2-hydroxypropyl (meth)acrylic acid, 3-hydroxypropyl (meth)acrylic acid, and 2-hydroxy(meth)acrylic acid. butyl, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc. are mentioned, These are used individually or in combination of 2 or more types.

Examples of the monomer containing a carboxyl group in the molecule include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These may be used independently and may be used in combination of 2 or more type.

Examples of the monomer containing an amino group in the molecule or the monomer containing a substituted amino group include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. These may be used independently and may be used in combination of 2 or more type.

In addition, the acrylic copolymer (a1), as a constituent monomer, is a (meth)acrylic acid alkyl ester having 3 to 20 carbon atoms in the alkyl group except for n-butyl acrylate, and a monomer having an alicyclic structure in the molecule (containing alicyclic structure) monomer) may be included.

As an example of the C3-C20 (meth)acrylic-acid alkylester of the alkyl group mentioned above, (meth)acrylic-acid propyl, (meth)acrylic-acid 2-ethylhexyl, etc. are used preferably. These may be used individually by 1 type, and may be used in combination of 2 or more type.

As the alicyclic structure-containing monomer, for example, (meth)acrylic acid cyclohexyl, (meth)acrylic acid dicyclopentanyl, (meth)acrylic acid adamantyl, (meth)acrylic acid isobornyl, (meth)acrylic acid dicyclopentenyl , (meth)acrylic acid dicyclopentenyloxyethyl, etc. are preferably used. These may be used individually by 1 type, and may be used in combination of 2 or more type.

In addition, the acrylic copolymer (a1) has side chains with respect to the main chain composed of n-butyl acrylate, 2-hydroxyethyl acrylate, (meth)acrylic acid alkyl ester having an alkyl group having 2 or less carbon atoms, and, if necessary, other monomers. as a compound may be bound. As an example of such a compound, the unsaturated group containing compound (a2) mentioned later is mentioned.

It is preferable that content of n-butyl acrylate in all the monomers which comprise the main chain of the acrylic copolymer (a1) is 20 mass % or more. Moreover, it is preferable that the said content is 85 mass % or less. When n-butyl acrylate is contained within the above range as a constituent monomer in the main chain of the acrylic copolymer (a1), the pressure-sensitive adhesive layer tends to exhibit excellent solvent resistance.

The content of 2-hydroxyethyl acrylate in all the monomers constituting the main chain of the acrylic copolymer (a1) is preferably 5 mass% or more, and particularly preferably 10 mass% or more. Moreover, it is preferable that it is 40 mass % or less, and, as for the said content, it is especially preferable that it is 30 mass % or less. When 2-hydroxyethyl acrylate is contained within the above range as a constituent monomer in the main chain of the acrylic copolymer (a1), the pressure-sensitive adhesive layer tends to exhibit excellent solvent resistance.

The content of (meth)acrylic acid alkylester having 2 or less alkyl carbon atoms in all monomers constituting the main chain of the acrylic copolymer (a1) is preferably 5 mass% or more, and particularly preferably 10 mass% or more. Moreover, it is preferable that it is 40 mass % or less, and, as for the said content, it is especially preferable that it is 30 mass % or less. When the (meth)acrylic acid alkylester having 2 or less carbon atoms in the alkyl group is included in the main chain of the acrylic copolymer (a1) in the above range as a constituent monomer, the pressure-sensitive adhesive layer tends to exhibit excellent solvent resistance.

In addition, in all the monomers constituting the main chain of the acrylic copolymer (a1), the mass ratio of the content of (meth)acrylic acid alkylester having 2 or less alkyl groups to the content of n-butyl acrylate is preferably 0.08 or more. and 0.1 or more is particularly preferable. Moreover, it is preferable that it is 1.0 or less, and, as for the said mass ratio, it is especially preferable that it is 0.9 or less. When the said mass ratio is the said range, it becomes easy to exhibit the solvent resistance excellent in an adhesive layer.

In addition, in all the monomers constituting the main chain of the acrylic copolymer (a1), the mass ratio of the content of (meth)acrylic acid alkyl ester having 2 or less alkyl groups to the content of 2-hydroxyethyl acrylate is 0.3 or more. It is preferable, and it is especially preferable that it is 0.4 or more. Moreover, it is preferable that it is 4.0 or less, and, as for the said mass ratio, it is especially preferable that it is 3.5 or less. When the said mass ratio is the said range, it becomes easy to exhibit the solvent resistance excellent in an adhesive layer.

In the adhesive sheet for stealth dicing which concerns on this embodiment, it is preferable that it is -50 degreeC or more, and, as for the glass transition temperature (Tg) of an acrylic copolymer (a1), it is especially preferable that it is -48 degreeC or more. Moreover, it is preferable that it is 0 degrees C or less, and, as for the said glass transition temperature (Tg), it is especially preferable that it is -8 degrees C or less. When the said glass transition temperature (Tg) is the said range, it becomes easy to exhibit the excellent solvent resistance of an adhesive layer. In addition, the detail of the measuring method of the said glass transition temperature (Tg) is as having described in the test example mentioned later.

In the adhesive sheet for stealth dicing which concerns on this embodiment, it is preferable that the dissolution parameter (SP value) of an acrylic copolymer (a1) is 9.06 or more. Moreover, it is preferable that the said dissolution parameter (SP value) is 10 or less. When the said dissolution parameter (SP value) is the said range, it becomes easy to exhibit the solvent resistance excellent in an adhesive layer.

In the adhesive sheet for stealth dicing which concerns on this embodiment, the adhesive layer is comprised from the energy-beam curable adhesive containing the above-mentioned acrylic copolymer (a1). By irradiating an energy ray because an adhesive layer is comprised by the energy-beam curable adhesive, an adhesive layer can be hardened and the adhesive force with respect to the workpiece|piece of the adhesive sheet for stealth dicing can be reduced. Thereby, it becomes possible to pick up the semiconductor chip obtained by stealth dicing from the adhesive sheet for stealth dicing easily.

The energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may include a polymer having energy ray curability as a main component, and a non-energy ray curable polymer (a polymer not having energy ray curability) and at least one energy ray curable group-containing monomer and / Or a mixture with an oligomer may be used as a main component. Further, a mixture of a polymer having energy ray curability and a non-energy ray curable polymer may be used, or a mixture of a polymer having energy ray curability and a monomer and/or oligomer having at least one energy ray curable group may be used, and these three types A mixture may be sufficient. Here, the above-mentioned acrylic copolymer (a1) may be contained as a polymer which has energy-beam sclerosis|hardenability in an energy-beam curable adhesive, and may be contained as a polymer which does not have energy-beam sclerosis|hardenability.

First, the case where an energy-beam curable adhesive has as a main component the polymer which has energy-beam sclerosis|hardenability is demonstrated below.

The polymer having energy ray curability is a (co)polymer (A) (hereinafter referred to as "energy ray curable polymer ( A)" is preferable). The energy ray-curable polymer (A) has a functional group bonded to the above-described acrylic copolymer (a1) and a functional group of the acrylic copolymer (a1) (eg, a hydroxyl group derived from 2-hydroxyethyl acrylate). It is preferable that it is what is obtained by making the unsaturated group containing compound (a2) which has it react.

By making the said acrylic copolymer (a1) react with the unsaturated group containing compound (a2) which has a functional group couple|bonded with the functional group, an energy-beam curable polymer (A) is obtained.

The functional group which the unsaturated group containing compound (a2) has can be suitably selected according to the kind of functional group which the acrylic copolymer (a1) has. The acrylic copolymer (a1) has a hydroxyl group derived from 2-hydroxyethyl acrylate, and when the hydroxyl group is used for reaction with the functional group of the unsaturated group-containing compound (a2), the unsaturated group-containing compound (a2) As a functional group which this has, an isocyanate group or an epoxy group is preferable. In addition, even when the acrylic copolymer (a1) has an amino group or a substituted amino group as a functional group and these are used for reaction with the functional group of the unsaturated group-containing compound (a2), as a functional group of the unsaturated group-containing compound (a2) An isocyanate group or an epoxy group is preferable. Further, when the acrylic copolymer (a1) has an epoxy group as a functional group and this is used for reaction with the functional group of the unsaturated group-containing compound (a2), the functional group of the unsaturated group-containing compound (a2) is an amino group, a carboxy group, or an azide group. A ridinyl group is preferred.

Further, the unsaturated group-containing compound (a2) contains at least one energy-beam polymerizable carbon-carbon double bond per molecule, preferably 1-6, more preferably 1-4. Specific examples of the 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 a diisocyanate compound or a polyisocyanate compound, and hydroxyethyl (meth)acrylate; Acryloyl monoisocyanate compound obtained by reaction of a diisocyanate compound or a polyisocyanate compound, a polyol compound, and hydroxyethyl (meth)acrylate; glycidyl (meth) acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, etc. are mentioned.

The unsaturated group-containing compound (a2) is preferably 50 mol% or more, particularly preferably 60 mol% or more, more preferably 70 mol% or more, based on the number of moles of the functional group-containing monomer of the acrylic copolymer (a1). It is used in a proportion of mole % or more. In addition, the unsaturated group-containing compound (a2) is preferably 95 mol% or less, particularly preferably 93 mol% or less, more preferably with respect to the number of moles of the monomer containing a functional group in the acrylic copolymer (a1). is used in a proportion of 90 mol% or less.

In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), depending on the combination of the functional group of the acrylic copolymer (a1) and the functional group of the unsaturated group-containing compound (a2), 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) reacts with the functional group in the unsaturated group-containing compound (a2), the unsaturated group is introduced into the side chain in the acrylic copolymer (a1), and the energy ray-curable polymer (A) is obtained

Thus, it is preferable that it is 10,000 or more, as for the weight average molecular weight (Mw) of the energy ray-curable polymer (A) obtained, it is especially preferable that it is 150,000 or more, It is more preferable that it is 200,000 or more. Moreover, it is preferable that it is 1.5 million or less, and, as for the said weight average molecular weight (Mw), it is especially preferable that it is 1 million or less. In addition, the weight average molecular weight (Mw) in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography method (GPC method).

Even when the energy ray-curable pressure-sensitive adhesive contains as a main component a polymer having energy ray curability like the energy ray-curable polymer (A), the energy ray-curable pressure-sensitive adhesive further contains an energy ray-curable monomer and/or oligomer (B). do.

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

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

When blending an energy ray-curable monomer and/or oligomer (B) with respect to the energy ray-curable polymer (A), the content of the energy ray-curable monomer and/or oligomer (B) in the energy ray-curable pressure-sensitive adhesive is, It is preferable that it is more than 0 mass parts with respect to 100 mass parts of energy ray-curable polymers (A), and it is especially preferable that it is 60 mass parts or more. Moreover, it is preferable that it is 250 mass parts or less, and, as for the said content, it is especially preferable that it is 200 mass parts or less with respect to 100 mass parts of energy ray-curable polymers (A).

Here, when using an ultraviolet-ray as an energy-beam for hardening an energy-beam curable adhesive, it is preferable to add a photoinitiator (C), By use of this photoinitiator (C), polymerization hardening time and light irradiation amount can be made less

Specifically, as a photoinitiator (C), benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate , benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexylphenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl , β-Chloroanthraquinone, (2,4,6-trimethylbenzyldiphenyl)phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo {2-hydroxy-2- methyl-1-[4-(1-propenyl)phenyl]propanone}, 2,2-dimethoxy-1,2-diphenylethan-1-one, and the like. These may be used independently and may use 2 or more types together.

The photoinitiator (C) is an energy ray-curable copolymer (A) (in the case of blending an energy ray-curable monomer and/or an oligomer (B), an energy ray-curable copolymer (A) and an energy ray-curable monomer and/ Or 100 parts by mass of the total amount of the oligomer (B)) It is preferably used in an amount of 0.1 parts by mass or more, particularly 0.5 parts by mass or more with respect to 100 parts by mass. In addition, a photoinitiator (C) is an energy-beam curable copolymer (A) (When mix|blending an energy-beam curable monomer and/or an oligomer (B), an energy-beam curable copolymer (A) and an energy-beam curable monomer and/or 100 parts by mass of the total amount of the oligomer (B)) It is preferably used in an amount of 10 parts by mass or less, particularly 6 parts by mass or less with respect to 100 parts by mass.

In an energy-beam curable adhesive, you may mix|blend other components suitably other than the said component. As another component, a non-energy-ray-curable polymer component or an oligomer component (D), a crosslinking agent (E), etc. are mentioned, for example.

Examples of the non-energy ray-curable polymer component or oligomer component (D) include polyacrylic acid esters, polyesters, polyurethanes, polycarbonates, and polyolefins, and polymers having a weight average molecular weight (Mw) of 30 to 2.5 million. or oligomers are preferred. By mix|blending the said component (D) with an energy-beam curable adhesive, the adhesiveness and peelability in before hardening, the intensity|strength after hardening, adhesiveness with another layer, storage stability, etc. can be improved. The compounding quantity of the said component (D) is not specifically limited, It determines suitably in the range of more than 0 mass parts and 50 mass parts or less with respect to 100 mass parts of energy ray-curable copolymers (A).

As a crosslinking agent (E), the polyfunctional compound which has reactivity with the functional group which an energy ray-curable copolymer (A) etc. has can be used. Examples of such a polyfunctional compound include an isocyanate compound, an epoxy compound, an amine compound, a melamine compound, an aziridine compound, a hydrazine compound, an aldehyde compound, an oxazoline compound, a metal alkoxide compound, a metal chelate compound, a metal salt, an ammonium salt, and a reactive phenol resin. and the like.

The compounding amount of the crosslinking agent (E) is preferably 0.01 parts by mass or more, particularly preferably 0.03 parts by mass or more, and more preferably 0.04 parts by mass or more with respect to 100 parts by mass of the energy ray-curable copolymer (A). Moreover, it is preferable that it is 8 mass parts or less with respect to 100 mass parts of energy ray-curable copolymer (A), and, as for the compounding quantity of a crosslinking agent (E), it is especially preferable that it is 5 mass parts or less, It is more preferable that it is 3.5 mass parts or less.

Next, the case where the energy ray-curable pressure-sensitive adhesive contains a mixture of a non-energy ray-curable polymer component and a monomer and/or an oligomer having at least one or more energy ray-curable groups as a main component will be described below.

As a non-energy-ray-curable polymer component, the above-mentioned acrylic copolymer (a1) is used.

It is preferable that it is 100,000 or more, and, as for the weight average molecular weight (Mw) of an acrylic copolymer (a1), it is especially preferable that it is 200,000 or more. Moreover, it is preferable that it is 1.3 million or less, and, as for the said weight average molecular weight (Mw), it is especially preferable that it is 1 million or less.

As the monomer and/or oligomer having at least one or more energy ray-curable groups, those similar to those of component (B) described above can be selected. The blending ratio of the non-energy ray-curable polymer component and the monomer and/or oligomer having at least one energy ray-curable group is, with respect to 100 parts by mass of the non-energy ray-curable polymer component, a monomer and/or oligomer having at least one energy ray-curable group. It is preferable that it is 1 mass part or more, and it is especially preferable that it is 60 mass parts or more. Further, the blending ratio is preferably 200 parts by mass or less, and particularly preferably 160 parts by mass or less, of a monomer and/or oligomer having at least one energy ray-curable group with respect to 100 parts by mass of the non-energy ray-curable polymer component.

Also in this case, similarly to the above, a photoinitiator (C) and a crosslinking agent (E) can be mix|blended suitably.

It is preferable that it is 1 micrometer or more, and, as for the thickness of an adhesive layer, it is especially preferable that it is 2 micrometers or more, It is more preferable that it is 3 micrometers or more. Moreover, it is preferable that the said thickness is 50 micrometers or less, It is especially preferable that it is 30 micrometers or less, It is more preferable that it is 20 micrometers or less. When the thickness of an adhesive layer is 1 micrometer or more, it becomes possible to block|block favorably that an organic solvent contacts a base material by an adhesive layer, and generation|occurrence|production of the wrinkles of a base material can be suppressed effectively. Moreover, when the thickness of an adhesive layer is 50 micrometers or less, it is suppressed that the adhesive force of the adhesive sheet for stealth dicing becomes high too much, and generation|occurrence|production of a pickup defect, etc. can be suppressed effectively.

(3) release sheet

In the adhesive sheet for stealth dicing which concerns on this embodiment, before affixing the adhesive surface in an adhesive layer to a work piece, in order to protect the said surface, the peeling sheet may be laminated|stacked on the said surface. The structure of a release sheet is arbitrary, and what carried out the peeling process of the plastic film with a release agent etc. is illustrated. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. As the release agent, silicone-based, fluorine-based, long-chain alkyl-based or the like can be used, and among these, a silicone-based that is safe and obtains stable performance is preferable. Although there is no restriction|limiting in particular about the thickness of a release sheet, Usually, they are 20 micrometers or more and 250 micrometers or less.

2. Manufacturing method of adhesive sheet for stealth dicing

The manufacturing method of the adhesive sheet for stealth dicing which concerns on this embodiment is not limited, as long as a base material achieves the above-mentioned tensile elasticity modulus, and an adhesive layer is comprised from the above-mentioned energy-beam curable adhesive.

For example, the adhesive sheet for stealth dicing can be obtained by transferring the adhesive layer formed on the peeling sheet to the single side|surface side of a base material. In this case, a coating solution further containing a pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer and, if desired, a solvent or a dispersion medium is prepared, and on the peeling-treated side of the release sheet (hereinafter referred to as “peelable side”), An adhesive layer can be formed by apply|coating this coating liquid with a die coater, a curtain coater, a spray coater, a slit coater, a knife coater, etc., forming a coating film, and drying the said coating film. The properties of the coating liquid are not particularly limited as long as it can be applied, and the component for forming the pressure-sensitive adhesive layer may be contained as a solute or may be contained as a dispersoid in some cases. The peeling sheet in this laminated body may peel as a process material, and before affixing the adhesive sheet for stealth dicing to a work piece, in order to protect the adhesive surface of an adhesive layer, you may use it.

When the coating liquid for forming the pressure-sensitive adhesive layer contains a crosslinking agent, by changing the above-described drying conditions (temperature, time, etc.) or by separately providing heat treatment, the energy ray-curable polymer (A) in the coating film Alternatively, a crosslinking reaction between the non-energy ray-curable polymer component and the crosslinking agent (E) may be advanced to form a crosslinked structure at a desired density in the pressure-sensitive adhesive layer. In order to sufficiently advance this crosslinking reaction, after laminating the pressure-sensitive adhesive layer on the substrate by the above-described method or the like, the obtained pressure-sensitive adhesive sheet for stealth dicing is left still in an environment of, for example, 23° C. and 50% relative humidity for several days. You may perform curing.

Instead of transferring the pressure-sensitive adhesive layer formed on the release sheet to the single side side of the substrate as described above, the pressure-sensitive adhesive layer may be formed directly on the substrate. In this case, an adhesive layer is formed by apply|coating the coating liquid for forming the above-mentioned adhesive layer to the single side side of a base material, forming a coating film, and drying the said coating film.

3. How to use the adhesive sheet for stealth dicing

The adhesive sheet for stealth dicing which concerns on this embodiment can be used for stealth dicing. Moreover, the adhesive sheet for stealth dicing which concerns on this embodiment can be used for the manufacturing method of a semiconductor device provided with the process of stealth dicing.

Since generation|occurrence|production of the crack of a workpiece|work is suppressed as mentioned above, the adhesive sheet for stealth dicing which concerns on this embodiment can be used suitably for a thin-thick workpiece|piece. For example, the adhesive sheet for stealth dicing which concerns on this embodiment can be used suitably for the semiconductor wafer (TSV) which has a through electrode.

Below, an example of the manufacturing method of the semiconductor device provided with the process of stealth dicing is demonstrated. First, a process of cutting (backgrinding) one side of a workpiece (semiconductor wafer) fixed to a rigid support is performed. The semiconductor wafer is fixed to a rigid support by, for example, an adhesive. As a hard support body, glass etc. are used, for example. The backgrind can be performed by a general method.

Then, the semiconductor wafer on which the backgrind was completed is transcribe|transferred from the hard support body to the adhesive sheet for stealth dicing. At this time, after sticking the surface by the side of the adhesive layer of the adhesive sheet for stealth dicing with respect to the back-grinded surface of a semiconductor wafer, a hard support body is isolate|separated from a semiconductor wafer. Separation of the hard support from the semiconductor wafer can be performed by a method depending on the type of adhesive used for fixing the hard support and the semiconductor wafer. The method of sliding from a wafer, the method of decomposing|disassembling an adhesive agent by laser beam irradiation, etc. are mentioned. Moreover, after a hard support body is isolate|separated from a semiconductor wafer, the peripheral part in the adhesive sheet for stealth dicing is affixed with respect to a ring frame.

Then, the process of washing|cleaning the semiconductor wafer laminated|stacked on the adhesive sheet for stealth dicing using a solvent is performed. Thereby, the adhesive agent which remains on a semiconductor wafer can be removed. The cleaning can be performed by a general method, for example, a method of immersing a laminate of a stealth dicing pressure-sensitive adhesive sheet and a semiconductor wafer in a solvent, a frame slightly larger than the semiconductor wafer, and the stealth dicing adhesion so as to surround the wafer The method of arrange|positioning on a sheet|seat and injecting|throwing-in a solvent in a frame, etc. are mentioned. As a solvent, an organic solvent etc. can be used, Especially, it is preferable to use an organic solvent from a viewpoint of effectively removing an adhesive agent. As a kind of organic solvent, it is preferable to use p-mentane, d-limonene, mesitylene, etc.

In the adhesive sheet for stealth dicing which concerns on this embodiment, when an adhesive layer is comprised with the energy-beam curable adhesive mentioned above, an adhesive layer exhibits the outstanding solvent resistance. While it is suppressed that the component in an adhesive layer elutes to the organic solvent and it originates in it and contaminates a semiconductor wafer is suppressed by this, it is suppressed that the adhesive force of the adhesive sheet for stealth dicing with respect to a semiconductor wafer falls. Moreover, since the adhesive layer excellent in solvent resistance is laminated|stacked on the single side side of a base material, even if it is a case where a solvent contacts with respect to the surface on the side of the adhesive layer in the adhesive sheet for stealth dicing, by an adhesive layer, the base material and the solvent contact is blocked. Thereby, generation|occurrence|production of the wrinkles in a base material, and generation|occurrence|production of the cracks, such as a semiconductor wafer resulting from it, are suppressed.

Then, you may laminate|stack another semiconductor wafer with respect to the semiconductor wafer laminated|stacked on the adhesive sheet for stealth dicing as needed. At this time, semiconductors can be fixed using an adhesive agent etc., for example, can be fixed by a nonconductive adhesive film (NCF). You may repeat lamination|stacking of a semiconductor wafer until it becomes the required number of lamination|stacking. Lamination of such a semiconductor wafer is performed especially, when using a TSV wafer as a semiconductor wafer, and manufacturing a laminated circuit, it is performed suitably.

Next, on the pressure-sensitive adhesive sheet for stealth dicing, a semiconductor wafer or a stack of semiconductor wafers (hereinafter, referred to as "semiconductor wafer", unless otherwise specified, shall refer to a semiconductor wafer or a stack of semiconductor wafers) of stealth dicing is performed. In this process, a laser beam is irradiated with respect to a semiconductor wafer, and a modified part is formed in a semiconductor wafer. Irradiation of a laser beam can be performed using the apparatus and conditions generally used in stealth dicing.

Then, a semiconductor wafer is divided|segmented in the modified part formed by stealth dicing, and a some semiconductor chip is obtained. The said division|segmentation can be performed by installing the laminated body of the adhesive sheet for stealth dicing, and a semiconductor wafer in an expanding apparatus, and expanding in 0 degreeC - room temperature environment, for example.

Then, the pressure-sensitive adhesive sheet for stealth dicing is expanded again. The said expanding is performed for the main purpose of separating the obtained semiconductor chips. In addition, the pressure-sensitive adhesive sheet for stealth dicing is adsorbed on the suction table while maintaining the expanded state. The expanding here can be performed at room temperature or in a heated state. In addition, expanding can be performed by a general method using a general apparatus, and the adsorption|suction table used can also be performed using a general thing.

Then, while the adhesive sheet for stealth dicing is adsorbed on the suction table, the area|region in which the semiconductor chip is not laminated|stacked in the adhesive sheet for stealth dicing on which the obtained semiconductor chip was laminated|stacked is contracted by heating (heat shrink). do. Specifically, the area|region in between the area|region in which the semiconductor chip in the adhesive sheet for stealth dicing was laminated|stacked, and the area|region in which the ring frame in the adhesive sheet for stealth dicing was affixed is heated, and the said area|region is contracted. . As heating conditions at this time, it is preferable to make the temperature of the adhesive sheet for stealth dicing into 90 degreeC or more. Moreover, it is preferable to make the temperature of the adhesive sheet for stealth dicing into 200 degrees C or less. Since the adhesive sheet for stealth dicing which concerns on this embodiment is the range mentioned above, the tensile elasticity modulus in 23 degreeC of a base material is excellent in heat shrink property.

Then, the adhesive sheet for stealth dicing is released|released from the adsorption|suction by the above-mentioned adsorption|suction table. In the heat shrink step, when the region between the region where the semiconductor chips in the pressure-sensitive adhesive sheet for stealth dicing is laminated and the region where the ring frame in the pressure-sensitive adhesive sheet for stealth dicing is pasted is contracted, In the pressure-sensitive adhesive sheet for stealth dicing, a force is generated to stretch the region to which the semiconductor chip is affixed in the peripheral direction. As a result, even after releasing from the adsorption|suction by the adsorption|suction table, the state in which the semiconductor chips were separated can be maintained.

Then, each semiconductor chip is picked up from the adhesive sheet for stealth dicing in the state which separated from the adjacent semiconductor chip. This pickup can be performed by a general method using a general apparatus. As described above, the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment exhibits excellent heat-shrink properties, and can maintain the semiconductor chips in a well-spaced state, whereby pickup can be performed favorably. there is.

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

For example, another layer may be provided between a base material and an adhesive layer, or in the surface on the opposite side to the adhesive layer in a base material.

(Example)

Hereinafter, the present invention will be described in more detail 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 description

A resin composition containing two types of random copolymers of polypropylene in a 1:1 ratio (50 parts by mass of Prime Polymer Co., Ltd. product name "Prime TPO F-3740" and 50 parts by mass of Prime Polymer Co., Ltd. product name "Prime TPO J-5710" mixture) was extruded with a small T-die extruder (manufactured by Toyo Seiki Industries, Ltd., product name "Laboplast Mill") to obtain a substrate having a thickness of 70 µm.

(2) Preparation of pressure-sensitive adhesive composition

An acrylic copolymer (a1) obtained by reacting 50 parts by mass of n-butyl acrylate (BA), 20 parts by mass of methyl acrylate (MA), and 30 parts by mass of 2-hydroxyethyl (HEA) acrylate, and the acrylic copolymer ( 80 mol% of methacryloyloxyethyl isocyanate (MOI) was made to react with respect to HEA of a1), and the energy-beam curable polymer (A) was obtained. When the molecular weight of this energy ray-curable polymer (A) was measured by the method mentioned later, the weight average molecular weight (Mw) was 500,000. Moreover, when the dissolution parameter (SP value) of the said acrylic copolymer (a1) was computed from the SP value of each monomer which comprises the said acrylic copolymer (a1), it was 9.61.

100 parts by mass of the obtained energy ray-curable polymer (in terms of solid content, the same applies below), 1.0 parts by mass of 1-hydroxycyclohexylphenyl ketone (manufactured by BASF, product name "Irgacure 184") as a photoinitiator, and toluene diisocyanate as a crosslinking agent (The Tosoh Corporation make, product name "Coronate L") 1.0 mass part was mixed in the solvent, and the adhesive composition was obtained.

(3) Formation of the pressure-sensitive adhesive layer

To the release surface of a release sheet (manufactured by Lintex, product name "SP-PET381031") having a silicone-based release agent layer formed on one side of a 38 µm-thick polyethylene terephthalate (PET) film, the pressure-sensitive adhesive composition is applied and heated By drying by the method, a pressure-sensitive adhesive layer having a thickness of 20 µm was formed on the release sheet.

(4) Preparation of adhesive sheet for stealth dicing

The adhesive sheet for stealth dicing was obtained by bonding together the surface on the opposite side to the peeling sheet of the adhesive layer formed in the said process (3), and the single side|surface of the base material produced in the said process (1).

[Examples 2 to 5]

Except changing the composition in an adhesive composition as shown in Table 1, it carried out similarly to Example 1, and manufactured the adhesive sheet for stealth dicing.

[Example 6]

A resin composition containing an ethylene-methacrylic acid copolymer (manufactured by Mitsui DuPont Poly Chemicals, product name “Nucler N0903HC”) was mixed with a small T-die extruder (manufactured by Toyo Seiki Seisakusho, product name “Laboplast Mill”). ), except for using the 70-micrometer-thick base material obtained by extrusion molding, it carried out similarly to Example 1, and manufactured the adhesive sheet for stealth dicing.

[Example 7]

A resin composition containing low-density polyethylene (manufactured by Sumitomo Chemical, product name "Sumikasen F-412-1") is extruded by a small T-die extruder (manufactured by Toyo Seiki Corporation, product name "Laboplast Mill"). Except using the 70-micrometer-thick base material obtained by shape|molding, it carried out similarly to Example 1, and manufactured the adhesive sheet for stealth dicing.

[Example 8]

Except changing the composition in an adhesive composition as shown in Table 1, it carried out similarly to Example 1, and manufactured the adhesive sheet for stealth dicing.

[Comparative Example 1]

Except changing the composition in an adhesive composition as shown in Table 1, it carried out similarly to Example 1, and manufactured the adhesive sheet for stealth dicing.

[Comparative Example 2]

While changing as the composition in an adhesive composition was shown in Table 1, except using the 80-micrometer-thick polybutylene terephthalate film as a base material, it carried out similarly to Example 1, and the adhesive sheet for stealth dicing was manufactured.

[Comparative Example 3]

While changing as the composition in an adhesive composition was shown in Table 1, except using a 50-micrometer-thick polyethylene terephthalate film as a base material, it carried out similarly to Example 1, and produced the adhesive sheet for stealth dicing.

Here, the above-mentioned weight average molecular weight (Mw) is the weight average molecular weight of standard polystyrene conversion measured using gel permeation chromatography (GPC) (GPC measurement).

In addition, the detail of the structural component shown in Table 1 is as follows.

[Composition of adhesive composition]

BA: n-butyl acrylate

MA: methyl acrylate

MMA: methyl methacrylate

·EA: ethyl acrylate

·HEA: Acrylic acid 2-hydroxyethyl

[Material of description]

·PP: polypropylene

·EMAA: ethylene-methacrylic acid copolymer

PE: Polyethylene

PBT: polybutylene terephthalate

PET: Polyethylene terephthalate

[Test Example 1] (Measurement of Glass Transition Temperature)

The glass transition temperature Tg of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for stealth dicing produced in Examples and Comparative Examples was measured by a differential scanning calorimeter (T A Instrument Japan, product name “DSC Q2000”). , was measured at a temperature increase/fall rate of 20°C/min. A result is shown in Table 1.

[Test Example 2] (Measurement of Tensile Modulus of Base Material)

The base material produced in the Example and the comparative example was cut into the test piece of 15 mm x 140 mm, and based on JISK7161:2014, the tensile modulus in the temperature of 23 degreeC and 50% of relative humidity was measured. Specifically, the test piece is subjected to a tensile test at a speed of 200 mm/min after setting the distance between the chucks to 100 mm in a tensile testing machine (manufactured by Oriente Co., Ltd., product name "Tensiron RTA-T-2M"), The tensile modulus (MPa) was measured. In addition, the measurement was performed in both the extrusion direction (MD) at the time of shaping|molding of a base material, and the direction (CD) perpendicular to this, and the average value of these measurement results was made into the tensile elastic modulus elongation at break. A result is shown in Table 1.

[Test Example 3] (Evaluation of solvent resistance)

The release sheet was peeled from the adhesive sheet for stealth dicing produced in the Example and the comparative example, the periphery of the adhesive surface of the exposed adhesive layer was affixed to the 6-inch ring frame, and it was set as the evaluation sample.

The surface on the side of the ring frame of the said evaluation sample was turned upward, and p-mentane as a solvent was dripped with respect to the center part of the adhesive surface of an adhesive layer. The said dripping was performed until the solvent spreads over the whole area|region to which the ring frame in the said adhesive surface is not affixed, and it was left to stand for 5 minutes after completion|finish of dripping.

Then, the solvent was removed from the adhesion surface top, the presence or absence of the change of the external appearance of the adhesive sheet in before and behind the addition of a solvent was confirmed visually, and solvent resistance was evaluated. And those in which there was no change in appearance were evaluated as "○", and those in which appearance changes such as wrinkles or whitening occurred were evaluated as "x".

[Test Example 4] (Evaluation of heat shrink property)

The release sheet was peeled from the pressure-sensitive adhesive sheet for stealth dicing produced in Examples and Comparative Examples, and for the pressure-sensitive adhesive surface of the exposed pressure-sensitive adhesive layer, using a pasting device (manufactured by Lintex, product name "RAD-2700 F/12"), It was attached to a silicon wafer (outer diameter: 8 inches, thickness: 100 µm, dry polish finish) and a ring frame (made of stainless steel).

Next, the silicon wafer affixed on the pressure-sensitive adhesive sheet for stealth dicing is irradiated with a laser beam having a wavelength of 1342 nm using a laser saw (manufactured by Disco Corporation, product name "DFL7361"), and the resulting chip size is 8 mm x 8 mm, a modified portion was formed in the silicon wafer.

Next, the silicon wafer and ring frame after laser beam irradiation to which the pressure-sensitive adhesive sheet for stealth dicing was affixed, installed in a die separator (manufactured by Disco, product name "DDS2300"), at 0 ° C., dropping speed 100 mm / sec, It was expanded (cool expanded) to 10 mm in the amount of expansion. Thereby, the semiconductor wafer was divided|segmented in the reforming part, and the some semiconductor chip of each chip size of 8 mm x 8 mm was obtained.

Then, the pressure-sensitive adhesive sheet for stealth dicing was expanded at a rate of dropping 1 mm/sec and an expanding amount of 7 mm. Furthermore, in the expanded state, after adsorbing the pressure-sensitive adhesive sheet for stealth dicing on the suction table, in the pressure-sensitive adhesive sheet for stealth dicing, between the region to which the semiconductor chip was affixed and the region to which the ring frame was affixed was heated. . As the heating conditions at this time, the set temperature of the IR heater was set to 600°C, the rotation speed was 1deg/sec, and the distance between the suction table and the heater supporting the pressure-sensitive adhesive sheet for stealth dicing was set to 13 mm. Thereby, the adhesive sheet for stealth dicing was heated to about 180 degreeC.

Then, the adhesive sheet for stealth dicing was released from the adsorption|suction by the adsorption|suction table, the distance between adjacent semiconductor chips was measured 5 points|pieces, and the average value was computed. And the case where the said average value was 20 micrometers or more was made into "(circle)", and the case less than 20 micrometers was made into "x", and heat shrink property was evaluated. A result is shown in Table 1.

[Table 1]

As Table 1 showed, the adhesive sheet for stealth dicing obtained in the Example was excellent in solvent resistance and heat shrink property.

The adhesive sheet for stealth dicing of this invention can use the semiconductor wafer which has a through electrode suitably for a workpiece|work.

Claims (12)

A pressure-sensitive adhesive sheet for stealth dicing comprising a substrate and an adhesive layer laminated on one side of the substrate,
The base material has a tensile modulus of 50 MPa or more and 200 MPa or less at 23°C,
The pressure-sensitive adhesive layer is composed of an energy ray-curable pressure-sensitive adhesive comprising an acrylic copolymer containing n-butyl acrylate, 2-hydroxyethyl acrylate, and (meth)acrylic acid alkyl ester having an alkyl group having 2 or less carbon atoms as constituent monomers.
An adhesive sheet for stealth dicing, characterized in that. According to claim 1,
The content of 2-hydroxyethyl acrylate in all the monomers constituting the main chain of the acrylic copolymer is 5% by mass or more and 40% by mass or less,
In all the monomers constituting the main chain of the acrylic copolymer, the content of the (meth)acrylic acid alkylester having 2 or less carbon atoms in the alkyl group is 5% by mass or more and 40% by mass or less.
An adhesive sheet for stealth dicing, characterized in that. According to claim 1,
In all the monomers constituting the main chain of the acrylic copolymer, the mass ratio of the content of (meth)acrylic acid alkyl ester having 2 or less carbon atoms in the alkyl group to the content of n-butyl acrylate is 0.08 or more and 1.0 or less. ,
In all the monomers constituting the main chain of the acrylic copolymer, the mass ratio of the content of (meth)acrylic acid alkylester having 2 or less carbon atoms in the alkyl group to the content of 2-hydroxyethyl acrylate is 0.3 or more, 4.0 Lee Ha-in
An adhesive sheet for stealth dicing, characterized in that. According to claim 1,
The glass transition temperature (Tg) of the acrylic copolymer is -50°C or more and 0°C or less, the pressure-sensitive adhesive sheet for stealth dicing. According to claim 1,
The dissolution parameter (SP value) of the acrylic copolymer is 9.06 or more and 10 or less. According to claim 1,
The (meth)acrylic acid alkyl ester having 2 or less carbon atoms in the alkyl group is methyl methacrylate, methyl acrylate or ethyl acrylate. The pressure-sensitive adhesive sheet for stealth dicing. According to claim 1,
The base material is an adhesive sheet for stealth dicing, characterized in that it consists of at least one selected from random polypropylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and ethylene-(meth)acrylic acid copolymer. According to claim 1,
An adhesive sheet for stealth dicing characterized in that a semiconductor wafer having a through electrode is used as a workpiece. According to claim 1,
It is used for the manufacturing method of the semiconductor device provided with the process of washing|cleaning the workpiece laminated|stacked on the said adhesive sheet for stealth dicing using a solvent, The adhesive sheet for stealth dicing characterized by the above-mentioned. According to claim 1,
It is used for the manufacturing method of the semiconductor device provided with the process of shrink|contracting by heating the area|region in which the said workpiece|work piece is not laminated|stacked in the said adhesive sheet for stealth dicing on which the workpiece|work was laminated|stacked, The use for stealth dicing characterized by the above-mentioned adhesive sheet. A backgrind process of cutting one side of a workpiece fixed to a rigid support;
A transfer step of transferring the cut-off workpiece from the rigid support to the surface on the pressure-sensitive adhesive layer side of the pressure-sensitive adhesive sheet for stealth dicing according to any one of claims 1 to 10;
a cleaning step of cleaning the workpiece laminated on the stealth dicing adhesive sheet using a solvent;
a reformed portion forming step of irradiating a laser beam to the cleaned work piece to form a modified portion in the work piece;
A division step of dividing the work piece in the reforming unit by expanding the pressure-sensitive adhesive sheet for stealth dicing to obtain a plurality of divided work pieces
A method of manufacturing a semiconductor device comprising: 12. The method of claim 11,
A separation step of re-expanding the pressure-sensitive adhesive sheet for stealth dicing after the division step to separate the plurality of separated pieces of the workpiece;
a heat shrink step of shrinking an area in the pressure-sensitive adhesive sheet for stealth dicing in which the plurality of individualized workpieces are not stacked by heating;
A pickup process of picking up each of the plurality of pieces of the work piece from the pressure-sensitive adhesive sheet for stealth dicing in the state separated from the adjacent piece of work piece.
A method of manufacturing a semiconductor device comprising: