JP2021153097A - Workpiece processing sheet - Google Patents

Abstract

To provide a workpiece processing sheet capable of suppressing the generation of cutting pieces, especially thread-like cutting pieces, generated in workpiece processing, without applying physical energy such as electron beam and γ rays.SOLUTION: Workpiece processing sheets 1A, 1B, 1C each include a base material 11 and an adhesive layer 12 laminated on one side of the base material 11. The base materials 11 of the workpiece processing sheets 1A, 1B and 1C include a resin layer 111a, resin layers 111b, 111c, and resin layers 111d, 111e, 111f, respectively, formed from a resin composition containing a polyolefin-based resin, the base material 11 having a crystallinity of 35% or more and 70% or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a work processing sheet used for processing a work such as a semiconductor wafer.

Semiconductor wafers such as silicon and gallium arsenide and various packages are manufactured in a large diameter state, cut (diced) into chips, peeled (picked up), and then moved to the next step, the mounting process. At this time, a work such as a semiconductor wafer is back grinded, diced, washed, and laminated on an adhesive sheet (hereinafter, may be referred to as a “work processing sheet”) provided with a base material and an adhesive layer. Processing such as drying, expanding, picking up, and mounting is performed.

In full-cut dicing, which is generally used as a specific method of dicing described above, the work is cut by a rotating round blade (dicing blade). At this time, not only the work but also the adhesive layer is usually cut, and a part of the base material is also cut so that the work laminated on the work processing sheet is surely cut. At this time, a cutting piece made of a material constituting the pressure-sensitive adhesive layer and the base material may be generated from the work processing sheet, and the chip obtained by cutting the work may be contaminated by the cutting piece. As one of the typical forms of the cutting piece, there is a thread-like cutting piece that adheres on the dicing line or near the cross section of the chip separated by dicing.

When the chip is sealed with a large amount of the above-mentioned thread-like cutting pieces attached to the chip, the thread-like cutting pieces adhering to the chip are decomposed by the heat of sealing, and this pyrolyzed product destroys the package or obtains. It may cause malfunction of the device. Since it is difficult to remove the thread-like cutting pieces by washing, the yield of the dicing process is significantly reduced due to the generation of the thread-like cutting pieces. Therefore, when dicing is performed using a work sheet, it is required to prevent the generation of thread-like cutting pieces.

For the purpose of suppressing the generation of the cut pieces, Patent Document 1 discloses an invention in which a polyolefin-based film irradiated with an electron beam or a γ (gamma) ray of 1 to 80 Mrad is used as a base film for a dicing sheet. Has been done. In the present invention, it is considered that cross-linking by covalent bond is formed in the resin constituting the base film by irradiation with electron beam or γ-ray, and the generation of cut pieces is suppressed.

Japanese Unexamined Patent Publication No. 5-211234

However, in the invention of Patent Document 1, since the irradiation of radiation such as electron beam or γ-ray is performed after the above resin is once formed into a film, the manufacturing process is increased by one, and the manufacturing cost is generally high. It tends to be higher than that of the base film of. Further, there is also a problem that the formation of the above-mentioned crosslinks proceeds excessively and the base film becomes excessively hard, and as a result, the base film is easily torn when used for processing the work.

The present invention has been made in view of such an actual situation, and can generate cutting pieces, particularly thread-like cutting pieces, generated during machining of a workpiece without giving physical energy such as electron beam or γ-ray. It is an object of the present invention to provide a work processing sheet that can be suppressed.

In order to achieve the above object, first, the present invention is a work processing sheet including a base material and an adhesive layer laminated on one side of the base material, and the base material is a polyolefin-based material. Provided is a work processing sheet comprising a resin layer formed from a resin composition containing a resin, wherein the crystallinity of the base material is 35% or more and 70% or less (Invention 1). ..

The work processing sheet according to the above invention (Invention 1) includes a resin layer formed from a resin composition containing a polyolefin-based resin, and the crystallinity of the base material is within the above range. Even when it is used for dicing using a rotating round blade without giving physical energy such as γ-rays, it is possible to satisfactorily suppress the generation of thread-like cutting pieces.

In the above invention (Invention 1), the proportion of the polyolefin-based resin in the resin composition is preferably 30% by mass or more and 100% by mass or less (Invention 2).

In the above inventions (Inventions 1 and 2), the resin composition preferably contains a thermoplastic elastomer other than the polyolefin-based resin (Invention 3).

In the above invention (invention), the thermoplastic elastomer is preferably an olefin-based elastomer (Invention 4).

In the above invention (Invention 4), the proportion of the olefin-based elastomer in the resin composition is preferably 1% by mass or more and 50% by mass or less (Invention 5).

In the above inventions (Inventions 1 to 5), the base material is preferably composed of the resin layer single layer (Invention 6).

In the above inventions (Inventions 1 to 5), it is preferable that the base material is composed of a plurality of layers, and at least one of them is the resin layer (Invention 7).

In the above inventions (Inventions 1 to 7), the thickness of the base material is preferably 25 μm or more and 300 μm or less (Invention 8).

In the above inventions (Inventions 1 to 8), the pressure-sensitive adhesive layer is preferably composed of an acrylic pressure-sensitive adhesive (Invention 9).

In the above inventions (Inventions 1 to 9), a dicing sheet is preferable (Invention 10).

The work processing sheet according to the present invention can suppress the generation of cutting pieces, particularly thread-like cutting pieces, generated during machining of the work without giving physical energy such as electron beams and γ-rays.

It is sectional drawing of the work processing sheet which concerns on one Embodiment of this invention. It is sectional drawing of the work processing sheet which concerns on another embodiment of this invention. It is sectional drawing of the work processing sheet which concerns on still another Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows a cross-sectional view of a work processing sheet according to an embodiment. The work processing sheet 1A shown in FIG. 1 includes a base material 11 and an adhesive layer 12 laminated on one side of the base material 11.

FIG. 2 shows a cross-sectional view of a work processing sheet according to another embodiment. The work processing sheet 1B shown in FIG. 2 also includes a base material 11 and an adhesive layer 12 laminated on one side of the base material 11.

FIG. 3 shows a cross-sectional view of a work processing sheet according to still another embodiment. The work processing sheet 1C shown in FIG. 3 also includes a base material 11 and an adhesive layer 12 laminated on one side of the base material 11.

In the work processing sheets 1A, 1B, and 1C according to the present embodiment, the base material 11 includes a resin layer formed from a resin composition containing a polyolefin-based resin. In particular, in the work processing sheet 1A shown in FIG. 1, the base material 11 is composed of the resin layer 111a single layer. Further, in the work processing sheet 1B shown in FIG. 2, the base material 11 is composed of two layers, all of which are resin layers 111b and 111c. Further, in the work processing sheet 1C shown in FIG. 3, the base material 11 is composed of three layers, all of which are resin layers 111d, 111e, 111f.

Further, in the workpiece processing sheets 1A, 1B, 1C according to the present embodiment, the crystallinity of the base material 11 is 35% or more and 70% or less.

Here, the following is expected as a mechanism for generating cutting chips from the base material of a general dicing sheet. First, during dicing, frictional heat is generated when the rotating round blade comes into contact with the base material. The frictional heat softens the contact portion of the base material with the rotating round blade, but in that state, the force of pulling the cut portion of the base material by the rotating round blade is applied to the base material. It is considered that the base material is scraped off while the cut portion of the material is stretched. It is considered that this produces cutting chips, particularly thread-like cutting pieces.

On the other hand, in the workpiece processing sheets 1A, 1B, 1C according to the present embodiment, the base material 11 includes a resin layer formed from a resin composition containing a polyolefin-based resin, and the base material 11 has a crystallinity of 35. When a force for pulling the cut portion of the base material 11 is applied as described above, the cut portion is easily cut before the cut portion is sufficiently stretched. As a result, the dicing can be completed by suppressing the generation of cutting pieces, particularly thread-like cutting pieces.

Such a cutting piece suppressing effect is exhibited without irradiating the base material 11 in the present embodiment with radiation such as an electron beam or a γ-ray. Therefore, the work processing sheets 1A, 1B, and 1C provided with the base material 11 can keep the manufacturing cost low as compared with the conventional work processing sheets manufactured by the method including the irradiation step.

From the viewpoint of more effectively obtaining the cutting piece suppressing effect, the crystallinity of the base material 11 is preferably 40% or more, and particularly preferably 42% or more. The upper limit of the crystallinity of the base material 11 is not particularly limited, and as described above, it may be 70% or less, particularly 65% or less, and further 63% or less. good. The crystallinity of the base material 11 is measured with respect to the base material 11 by X-ray diffraction, and the details of the measurement method are as described in a test example described later. In particular, when the base material 11 is composed of a plurality of layers (such as when a plurality of resin layers are provided or when the base material 11 is provided with a resin layer and other layers), the crystallinity of the base material 11 is the base material 11 It is obtained by measuring the whole object.

1. 1. Structure of Sheet for Work Processing (1) Base Material The base material 11 in the present embodiment includes a resin layer formed from a resin composition containing a polyolefin-based resin. The base material 11 may be composed of only a single layer, and in that case, as shown in FIG. 1, the base material 11 is composed of only the resin layer 111a. The base material 11 made of the resin layer 111a single layer is preferable in terms of suppressing the manufacturing cost. Further, the base material 11 may be composed of a plurality of layers, in which case at least one layer thereof is a resin layer. The base material 11 shown in FIG. 2 is composed of two layers, all of which are resin layers (resin layer 111b and resin layer 111c, respectively). The base material 11 shown in FIG. 3 is composed of three layers, all of which are resin layers (resin layer 111d, resin layer 111e, and resin layer 111f, respectively). A base material composed of a plurality of layers is preferable in that it can achieve both a cutting piece suppressing effect mainly caused by the resin layer and a desired effect obtained by a layer other than the resin layer.

The components other than the polyolefin-based resin contained in the resin composition for forming the resin layer are not particularly limited as long as they enable the formation of the resin layer. The resin composition also preferably contains a thermoplastic elastomer. By containing the thermoplastic elastomer, the crystallinity of the base material 11 can be easily adjusted to the above-mentioned range, and the cutting piece suppressing effect can be obtained more effectively accordingly.

When the base material 11 includes a layer other than the resin layer, the material of the layer is not particularly limited as long as the layer and the base material 11 can be formed.

(1-1) Polyolefin-based resin Specific examples of the polyolefin-based resin contained in the resin composition for forming the resin layer are not particularly limited. In the present specification, the polyolefin-based resin is a homopolymer or copolymer having an olefin as a monomer, or a copolymer having an olefin and a molecule other than the olefin as a monomer, and is an olefin unit in the resin after polymerization. Refers to a resin in which the mass ratio of the portion based on is 1.0 mass% or more.

The polymer constituting the polyolefin resin may be linear or may have a side chain. Further, the polyolefin-based resin may have a functional group. The functional group may be an aromatic ring or an aliphatic ring, or may be an acyclic functional group.

Examples of the olefin monomer constituting the polyolefin resin include an olefin monomer having 2 to 8 carbon atoms, an α-olefin monomer having 3 to 18 carbon atoms, and an olefin monomer having a cyclic structure. .. Examples of the olefin monomer having 2 to 8 carbon atoms include ethylene, propylene, 2-butene, and octene. Examples of the α-olefin monomer having 3 to 18 carbon atoms include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, and 1 -Octane, etc. are exemplified. Examples of the olefin monomer having a cyclic structure include norbornene, cyclopentadiene, cyclohexadiene, dicyclopentadiene and tetracyclododecene, and derivatives thereof.

When the polyolefin-based resin contains polyethylene, the polyethylene may be any of high-density polyethylene, medium-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, and linear low-density polyethylene, and these two. It may be a mixture of seeds or more.

As the polyolefin-based resin, one type can be used alone or two or more types can be mixed and used.

Among the specific examples of the polyolefin-based resin described above, at least one of polyethylene containing ethylene as a main polymerization unit and polypropylene containing propylene as a main polymerization unit shall be used from the viewpoint of easily achieving the above-mentioned crystallinity. Is preferable.

As the polyprepylene, for example, homopolypropylene, random polypropylene and block polypropylene are preferably used. These can be used alone or in admixture of two or more. In particular, from the viewpoint of easily achieving the above-mentioned crystallinity, it is preferable to use a mixture of homopolypropylene and random polypropylene.

As the above-mentioned homopolypropylene, random polypropylene and block polypropylene, commercially available products on the market may be used. Examples of commercially available homopolypropylene products include the product name "Prime Polypro E111G", the product name "Prime Polypro E-100GV", the product name "Prime Polypro E-100GPL", and the product name "Prime Polypro E-100GPL" manufactured by Prime Polymer Co., Ltd. "E-200GP" and the like can be mentioned. Examples of commercially available random polypropylene products include the product name "Prime Polypro B221WA", the product name "Prime Polypro B241", the product name "Prime Polypro E222", and the product name "Prime Polypro E-333GV" manufactured by Prime Polymer Co., Ltd. And so on. Examples of commercially available block polypropylene products include the product name "Prime Polypro E701G", the product name "Prime Polypro E702G", and the product name "Prime Polypro E702MG" manufactured by Prime Polymer Co., Ltd.

As the above-mentioned polyethylene, it is preferable to use low-density polyethylene, and examples of commercially available products include the product name "Novatec LL" manufactured by Mitsubishi Chemical Corporation, and the Neo-Zex series and Ultra-Zex series manufactured by Prime Polymer Co., Ltd. Be done.

The proportion of the polyolefin-based resin in the resin composition for forming the resin layer is preferably 30% by mass or more, particularly preferably 40% by mass or more, and further preferably 65% by mass or more. preferable. Further, the above ratio is preferably 100% by mass or less, particularly preferably 95% by mass or less, and further preferably 90% by mass or less. When the proportion of the polyolefin-based resin in the resin composition is within the above range, the workpiece processing sheets 1A, 1B, and 1C according to the present embodiment can easily achieve a better cutting piece suppressing effect.

(1-2) Thermoplastic Elastomer The above-mentioned thermoplastic elastomer is not particularly limited as long as it is other than the above-mentioned polyolefin resin and enables the formation of the base material 11. Examples of thermoplastic elastomers include olefin-based elastomers, rubber elastomers, urethane-based elastomers, styrene-based elastomers, acrylic-based elastomers, vinyl chloride-based elastomers, and the like. These may be used alone or in combination of two or more.

Among the above-mentioned elastomers, an olefin-based elastomer is preferable from the viewpoint that the base material 11 can easily achieve the above-mentioned crystallinity. In the present specification, the "olefin-based elastomer" is a copolymer containing a structural unit derived from an olefin or a derivative thereof (olefin-based compound), and has rubber-like elasticity in a temperature range including room temperature. , Means a material having thermoplasticity.

Examples of olefin-based elastomers include ethylene / α-olefin copolymers, propylene / α-olefin copolymers, butene / α-olefin copolymers, ethylene / propylene / α-olefin copolymers, and ethylene / butene / Examples thereof include those containing at least one resin selected from the group consisting of α-olefin copolymers, propylene / butene / α-olefin copolymers and ethylene / propylene / butene / α-olefin copolymers. Among these, a propylene / α-olefin copolymer is preferable, and a propylene / ethylene / α-butylene copolymer is particularly preferable.

The proportion of the thermoplastic elastomer in the resin composition for forming the resin layer is preferably 1% by mass or more, particularly preferably 10% by mass or more, and further preferably 15% by mass or more. preferable. Further, the above ratio is preferably 60% by mass or less, particularly preferably 30% by mass or less, and further preferably 20% by mass or less. When the proportion of the thermoplastic elastomer in the resin composition is in the above range, the above-mentioned crystallinity can be easily achieved, and thus the workpiece processing sheets 1A, 1B, 1C according to the present embodiment are better. It becomes easy to achieve a good cutting piece suppressing effect.

When the thermoplastic elastomer is an olefin-based elastomer, the proportion of the olefin-based elastomer in the resin composition for forming the resin layer is preferably 1% by mass or more, and particularly 10% by mass or more. Is preferable, and more preferably 13% by mass or more. Further, the above ratio is preferably 50% by mass or less, particularly preferably 20% by mass or less, and further preferably 17% by mass or less. When the ratio of the olefin-based elastomer in the resin composition is in the above range, the above-mentioned crystallinity can be easily achieved, whereby the workpiece processing sheets 1A, 1B, 1C according to the present embodiment are better. It becomes easy to achieve a good cutting piece suppressing effect.

Although the resin composition for forming the resin layer may contain a styrene-based elastomer as the thermoplastic elastomer, the content thereof may be small from the viewpoint of easily achieving the above-mentioned crystallinity. Preferably, it is particularly preferable that the resin composition does not substantially contain a styrene-based elastomer. In the present specification, the "styrene-based elastomer" is a copolymer containing a structural unit derived from styrene or a derivative thereof (styrene-based compound), and has rubber-like elasticity in a temperature range including normal temperature. , Means a material having thermoplasticity.

When the resin composition contains a styrene-based elastomer, the proportion thereof is preferably less than 10% by mass, particularly preferably 5% by mass or less, and further preferably 1% by mass or less. The above-mentioned case where the styrene-based elastomer is substantially not contained means that the proportion of the styrene-based elastomer in the resin composition is 0.2% by mass or less.

(1-3) Other Components The resin composition for forming the resin layer may contain other components other than the above-mentioned polyolefin-based resin and thermoplastic elastomer. In particular, the resin composition may contain a component used as a base material for a general work processing sheet.

Examples of such components include various additives such as antistatic agents, flame retardants, plasticizers, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, ion scavengers and the like. The content of these additives is not particularly limited, but is preferably in the range in which the base material exhibits a desired function.

Above all, the resin composition for forming the resin layer preferably contains an antistatic agent. Examples of the antistatic agent include a low molecular weight antistatic agent and a polymer type antistatic agent, but the polymer type antistatic agent is preferable, and the polymer type antistatic agent has a sulfonate in the molecule. Examples thereof include vinyl copolymers, alkyl sulfonates, alkyl benzene sulfonates, betaines and the like. Further, examples thereof include a salt of an inorganic protonic acid of a polyether, a polyamide elastomer, a polyester elastomer, a polyether amide, or a polyether ester amide. Examples of the salt of the inorganic protonic acid include an alkali metal salt, an alkaline earth metal, a zinc salt, and an ammonium salt.

When the resin composition for forming the resin layer contains an antistatic agent, the proportion of the antistatic agent in the resin composition is preferably 3% by mass or more and 20% by mass or less. When the ratio of the antistatic agent in the resin composition is in the above range, the obtained base material 11 tends to have good antistatic properties.

(1-4) Surface Treatment of Base Material The surface of the base material 11 on which the pressure-sensitive adhesive layer 12 is laminated is subjected to primer treatment, corona treatment, plasma treatment, and roughening in order to improve adhesion to the pressure-sensitive adhesive layer 12. Surface treatment such as surface treatment (mat treatment) may be applied. Examples of the roughening treatment include an embossing method and a sandblasting method. Among these, it is preferable to perform embossing.

(1-5) Method for producing base material The method for producing the base material 11 in the present embodiment is not particularly limited as long as the above-mentioned resin composition is used, and for example, a melt extrusion method such as a T-die method or a round-die method; Calendar method: A solution method such as a dry method or a wet method can be used. Among these, from the viewpoint of efficiently producing the base material, it is preferable to adopt the melt extrusion method, and it is particularly preferable to adopt the T-die method.

When the base material 11 composed of only a single resin layer is produced by a melt extrusion method, the resin composition is kneaded, and pellets are produced directly from the obtained kneaded product or once pellets are produced, and then a known extruder is used. A film may be formed. In this case, it is preferable to immediately cool to room temperature using a cooling roll or the like immediately after extruding by the extruder from the viewpoint of easily achieving the above-mentioned crystallinity.

When the base material 11 composed of a plurality of layers is produced by a melt extrusion method, the components constituting each layer are kneaded, and pellets are produced directly from the obtained kneaded product or once pellets are produced, and then a known extruder is used. Then, a plurality of layers may be extruded at the same time to form a film. In this case as well, from the viewpoint of easily achieving the above-mentioned crystallinity, it is preferable to immediately cool to room temperature immediately after extrusion.

(1-6) Thickness of Base Material The thickness of the base material 11 in the present embodiment is preferably 25 μm or more, and particularly preferably 50 μm or more. The thickness of the base material 11 is preferably 300 μm or less, particularly preferably 200 μm or less, and further preferably 150 μm or less. When the thickness of the base material is 25 μm or more, the workpiece processing sheets 1A, 1B, 1C tend to have appropriate strength, and the workpiece fixed on the workpiece processing sheets 1A, 1B, 1C is good. It will be easy to support. Further, when the thickness of the base material 11 is 300 μm or less, the thicknesses of the workpiece processing sheets 1A, 1B, and 1C have good flexibility, and for example, it becomes easy to perform good expansion.

(2) Adhesive Layer The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 12 in the present embodiment has sufficient adhesive strength to the adherend (particularly, adhesive strength to the work that is sufficient for processing the work). It is not particularly limited as long as it can exert. Examples of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 12 include acrylic pressure-sensitive adhesive, rubber-based pressure-sensitive adhesive, silicone-based pressure-sensitive adhesive, urethane-based pressure-sensitive adhesive, polyester-based pressure-sensitive adhesive, polyvinyl ether-based pressure-sensitive adhesive, and the like. Among these, it is preferable to use an acrylic pressure-sensitive adhesive from the viewpoint of easily exerting a desired adhesive strength.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 12 in the present embodiment may be a pressure-sensitive adhesive having no active energy ray-curable property, but has an active energy ray-curable property (hereinafter, "active energy ray-curable property"). It may be referred to as "adhesive"). Since the pressure-sensitive adhesive layer 12 is composed of an active energy ray-curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer 12 is cured by irradiation with active energy rays, and the work processing sheets 1A, 1B, and 1C are adhered to the adherend. The force can be easily reduced. In particular, by irradiating with active energy rays, the workpiece after processing can be easily separated from the workpiece processing sheets 1A, 1B, 1C.

The active energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 12 may be mainly composed of a polymer having active energy ray-curability, or an active energy ray-non-curable polymer (active energy ray-curable). It may be mainly composed of a mixture of a non-natural polymer) and a monomer and / or an oligomer having at least one or more active energy ray-curable groups. Further, the active energy ray-curable pressure-sensitive adhesive may be a mixture of a polymer having active energy ray-curable property and a monomer and / or an oligomer having at least one or more active energy ray-curable groups.

The above-mentioned polymer having active energy ray curability is a (meth) acrylic acid ester polymer in which a functional group having active energy ray curability (active energy ray curable group) is introduced into a side chain (hereinafter, "active energy ray curable"). It may be referred to as "sex polymer"). This active energy ray-curable polymer may be obtained by reacting an acrylic polymer having a functional group-containing monomer unit with an unsaturated group-containing compound having a functional group bonded to the functional group. preferable. In addition, in this specification, (meth) acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms. Furthermore, the concept of "polymer" shall also be included in "polymer".

The above-mentioned acrylic polymer having a functional group-containing monomer unit may be obtained by polymerizing other monomers together with the functional group-containing monomer. As such a functional group-containing monomer and other monomers, and the unsaturated group-containing compound described above, known ones can be used, and for example, those disclosed in International Publication No. 2018/084021 shall be used. Can be done.

The weight average molecular weight of the active energy ray-curable polymer is preferably 10,000 or more, particularly preferably 150,000 or more, and further preferably 200,000 or more. The weight average molecular weight is preferably 1.5 million or less, and particularly preferably 1 million or less. The weight average molecular weight (Mw) in the present specification is a standard polystyrene-equivalent value measured by a gel permeation chromatography method (GPC method).

As the above-mentioned active energy ray non-curable polymer component, for example, the above-mentioned acrylic polymer before reacting with an unsaturated group-containing compound can be used.

The weight average molecular weight of the acrylic polymer as the active energy ray non-curable polymer component is preferably 10,000 or more, particularly preferably 150,000 or more, and further preferably 200,000 or more. .. The weight average molecular weight is preferably 1.5 million or less, and particularly preferably 1 million or less.

Further, as the above-mentioned monomer and / or oligomer having at least one active energy ray-curable group, for example, an ester of a polyhydric alcohol and (meth) acrylic acid can be used.

When ultraviolet rays are used as the active energy rays for curing the active energy ray-curable pressure-sensitive adhesive, it is preferable to add a photopolymerization initiator to the pressure-sensitive adhesive. Further, an active energy ray non-curable polymer component or an oligomer component, a cross-linking agent or the like may be added to the pressure-sensitive adhesive.

The thickness of the pressure-sensitive adhesive layer 12 in the present embodiment is preferably 1 μm or more, particularly preferably 3 μm or more, and further preferably 5 μm or more. The thickness of the pressure-sensitive adhesive layer 12 is preferably 70 μm or less, particularly preferably 30 μm or less, and further preferably 10 μm or less. When the thickness of the pressure-sensitive adhesive layer 12 is within the above-mentioned range, the work processing sheets 1A, 1B, and 1C according to the present embodiment can easily exhibit the desired adhesiveness.

(3) Release Sheet In the work processing sheets 1A, 1B, 1C according to the present embodiment, the surface of the pressure-sensitive adhesive layer 12 opposite to the base material 11 (hereinafter, may be referred to as “adhesive surface”) is used as a work. A release sheet may be laminated on the surface for the purpose of protecting the surface until it is attached to the surface.

The structure of the release sheet is arbitrary, and examples thereof include a plastic film peeled with a release agent or the like. 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, a silicone type, a fluorine type, a long chain alkyl type or the like can be used, and among these, a silicone type which can obtain stable performance at a low cost is preferable.

The thickness of the release sheet is not particularly limited, and may be, for example, 20 μm or more and 250 μm or less.

(4) Others In the work processing sheets 1A, 1B, and 1C according to the present embodiment, the adhesive layer may be laminated on the surface of the pressure-sensitive adhesive layer 12 opposite to the base material 11. In this case, the workpiece processing sheets 1A, 1B, 1C according to the present embodiment can be used as a dicing / die bonding sheet. In the sheet, a work is attached to the surface of the adhesive layer opposite to the pressure-sensitive adhesive layer 12, and the adhesive layer is diced together with the work to obtain a chip in which individualized adhesive layers are laminated. Obtainable. The individualized adhesive layer allows the chip to be easily fixed to the object on which the chip is mounted. As the material constituting the adhesive layer described above, a material containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, a material containing a B stage (semi-curable) thermosetting adhesive component, and the like are used. It is preferable to use it.

Further, in the work processing sheets 1A, 1B, 1C according to the present embodiment, the protective film forming layer may be laminated on the adhesive surface of the adhesive layer 12. In this case, the workpiece processing sheets 1A, 1B, 1C according to the present embodiment can be used as a protective film forming and dicing sheet. In such a sheet, a work is attached to the surface of the protective film forming layer opposite to the pressure-sensitive adhesive layer 12, and the protective film forming layer is diced together with the work to obtain an individualized protective film forming layer. Stacked chips can be obtained. As the work, it is preferable to use a work having a circuit formed on one surface, and in this case, a protective film forming layer is usually laminated on a surface opposite to the surface on which the circuit is formed. The individualized protective film forming layer is cured at a predetermined timing to form a protective film having sufficient durability on the chip. The protective film forming layer is preferably made of an uncured curable adhesive.

2. Manufacturing Method of Work Processing Sheet The manufacturing method of the work processing sheets 1A, 1B, 1C according to the present embodiment is not particularly limited. For example, after forming the pressure-sensitive adhesive layer 12 on the release sheet, one side of the base material 11 is laminated on the surface of the pressure-sensitive adhesive layer 12 opposite to the release sheet, so that the work processing sheets 1A, 1B, 1C It is preferable to obtain.

The above-mentioned adhesive layer 12 can be formed by a known method. For example, a pressure-sensitive composition for forming the pressure-sensitive adhesive layer 12 and, if desired, a coating liquid containing a solvent or a dispersion medium are prepared. Then, the coating liquid is applied to the peelable surface of the release sheet (hereinafter, may be referred to as "peeling surface"). Subsequently, the pressure-sensitive adhesive layer 12 can be formed by drying the obtained coating film.

The above-mentioned coating liquid can be applied by a known method, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like. The properties of the coating liquid are not particularly limited as long as it can be coated, and the coating liquid may contain a component for forming the pressure-sensitive adhesive layer 12 as a solute or a dispersoid. be. Further, the release sheet may be peeled off as a process material, or the pressure-sensitive adhesive layer 12 may be protected until it is attached to the adherend.

When the adhesive composition for forming the adhesive layer 12 contains the above-mentioned cross-linking agent, by changing the above-mentioned drying conditions (temperature, time, etc.) or by separately providing a heat treatment. It is preferable to proceed the cross-linking reaction between the polymer component in the coating film and the cross-linking agent to form a cross-linked structure in the pressure-sensitive adhesive layer 12 at a desired abundance density. Further, in order to allow the above-mentioned cross-linking reaction to proceed sufficiently, after the pressure-sensitive adhesive layer 12 and the base material 11 are bonded together, they are cured by, for example, allowing them to stand in an environment at 23 ° C. and a relative humidity of 50% for several days. May be good.

3. 3. Method of using the work processing sheet The work processing sheets 1A, 1B, 1C according to the present embodiment can be used for processing a work such as a semiconductor wafer. That is, after the adhesive surfaces of the work processing sheets 1A, 1B, 1C according to the present embodiment are attached to the work, the work can be processed on the work processing sheets 1A, 1B, 1C. Depending on the processing, the work processing sheets 1A, 1B, 1C according to the present embodiment will be used as a back grind sheet, a dicing sheet, an expanding sheet, a pickup sheet, and the like. Here, examples of the work include semiconductor members such as semiconductor wafers and semiconductor packages, and glass members such as glass plates.

As described above, the workpiece processing sheets 1A, 1B, and 1C according to the present embodiment satisfactorily suppress the generation of cutting pieces, particularly thread-like cutting pieces, when used for dicing using a rotating round blade. Can be done. Therefore, the work processing sheets 1A, 1B, and 1C according to the present embodiment are particularly preferably used as a dicing sheet among the above-mentioned work processing sheets.

When the work processing sheets 1A, 1B, 1C according to the present embodiment include the above-mentioned adhesive layer, the work processing sheets 1A, 1B, 1C can be used as a dicing / die bonding sheet. can. Further, when the work processing sheets 1A, 1B, 1C according to the present embodiment include the above-mentioned protective film forming layer, the work processing sheets 1A, 1B, 1C are used as a protective film forming and dicing sheet. can do.

Further, when the pressure-sensitive adhesive layer 12 in the work processing sheets 1A, 1B, 1C according to the present embodiment is composed of the above-mentioned active energy ray-curable pressure-sensitive adhesive, the following activities are observed during use. Irradiation with energy rays is also preferable. That is, when the processing of the work is completed on the work processing sheets 1A, 1B, 1C and the processed work is separated from the work processing sheets 1A, 1B, 1C, the adhesive layer 12 is prior to the separation. It is preferable to irradiate the active energy rays. As a result, the pressure-sensitive adhesive layer 12 is cured, the adhesive force of the pressure-sensitive adhesive sheet to the processed work is satisfactorily reduced, and the processed work can be easily separated.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, another layer is formed between the base material 11 and the pressure-sensitive adhesive layer 12 in the work processing sheets 1A, 1B, 1C according to the present embodiment, or on the surface of the base material 11 opposite to the pressure-sensitive adhesive layer 12. May be laminated.

Hereinafter, the present invention will be described in more detail with reference to 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 base material 70 parts by mass of random polypropylene resin (manufactured by Prime Polymer Co., Ltd., product name "Prime Polypro E222"), 10 parts by mass of homopolypropylene resin (manufactured by Prime Polymer Co., Ltd., product name "Prime Polypro E100-GPL") , Olefin-based thermoplastic elastomer (manufactured by Mitsui Chemicals, product name "Toughmer PN2070", propylene unit: ethylene unit: α-butylene unit = 70:15:15) 15 parts by mass, and antistatic agent (manufactured by Sanyo Kasei Co., Ltd., Product name "Perestat") 5 parts by mass were dried and then kneaded with a twin-screw kneader.

The pellets thus obtained were put into the hopper of a single-screw extruder equipped with a T-die. Then, under the conditions of a cylinder temperature of 200 ° C. and a die temperature of 200 ° C., the pellets are extruded from the T-die in a melt-kneaded state and immediately cooled by a cooling roll to obtain a sheet-like base material having a thickness of 80 μm. Obtained.

(2) Preparation of Adhesive Composition 38 parts by mass of 2-ethylhexyl acrylate, 37 parts by mass of vinyl acetate, and 25 parts by mass of 2-hydroxyethyl acrylate are polymerized by a solution polymerization method to obtain (meth) acrylic. An acid ester polymer was obtained. 30 g (corresponding to 80 mol% with respect to 2-hydroxyethyl acrylate) of the (meth) acrylic acid ester polymer and 30 g of the (meth) acrylic acid ester polymer with respect to 100 g of the (meth) acrylic acid ester polymer (MOI). ), To obtain an acrylic polymer in which an active energy ray-curable group was introduced into the side chain. The weight average molecular weight (Mw) of this acrylic polymer was measured by the method described later and found to be 600,000.

100 parts by mass (solid content equivalent, the same applies hereinafter) of the acrylic polymer obtained above in which an active energy ray-curable group is introduced into the side chain, and 1-hydroxy-cyclohexyl-phenyl-as a photopolymerization initiator. 7 parts by mass of ketone (BASF, product name "Omnirad 184") and 0.2 parts by mass of trimethylol propane-modified tolylene diisocyanate (Tosoh, product name "Coronate L") as a cross-linking agent in a solvent. To obtain a coating solution of the adhesive composition.

(3) Formation of Adhesive Layer Against the peeling surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET38131") in which a silicone-based release agent layer is formed on one side of a 38 μm-thick polyethylene terephthalate film. The coating liquid of the adhesive composition obtained in the above step (2) was applied and dried by heating to obtain a laminated body in which an adhesive layer having a thickness of 5 μm was formed on the release sheet. ..

(4) Preparation of Adhesive Sheet For workpiece processing by adhering one side of the base material obtained in the above step (1) to the surface of the laminate obtained in the above step (3) on the adhesive layer side. I got a sheet.

Here, the above-mentioned weight average molecular weight (Mw) is a standard polystyrene-equivalent weight average molecular weight measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
<Measurement conditions>
-Measuring device: HLC-8320 manufactured by Tosoh Corporation
-GPC column (passed in the following order): TSK gel superH-H manufactured by Tosoh Corporation
TSK gel superHM-H
TSK gel superH2000
-Measurement solvent: tetrahydrofuran-Measurement temperature: 40 ° C

[Example 2]
The blending amount of the material of the base material was changed to 65 parts by mass of the random polypropylene resin, 5 parts by mass of the homopolypropylene resin, 25 parts by mass of the olefin-based thermoplastic elastomer, and 5 parts by mass of the antistatic agent, in the same manner as in Example 1. Obtained a work sheet.

[Example 3]
A three-layered base material was prepared using the following materials. That is, low-density polyethylene (LDPE) as a material for forming the first layer (manufactured by Mitsubishi Chemical Co., Ltd., product name "Novatec LL UF442"), homopolypropylene resin (PP) as a material for forming the second layer. (Manufactured by Prime Polymer, product name "Prime Polypropylene E100-GPL"), and low-density polyethylene (LDPE) as a material for forming the third layer (manufactured by Mitsubishi Chemical Co., Ltd., product name "Novatec LL UF442"). It was co-extruded using a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Laboplast Mill").

As a result, a base material was obtained in which a layer of LDPE having a thickness of 10 μm, a layer of PP having a thickness of 60 μm, and a layer of LDPE having a thickness of 10 μm were laminated in this order. Further, one side of the base material was embossed with a satin finish.

A work processing sheet is obtained by adhering the surface on the pressure-sensitive adhesive layer side of the obtained laminate in the same manner as in step (3) in Example 1 to the embossed surface of the base material thus obtained. rice field.

[Comparative Example 1]
Ethylene / methacrylic acid copolymer (EMAA) (manufactured by Mitsui / DuPont Polychemical, product name "Nucrel N0903HC") is extruded by a small T-die extruder (manufactured by Toyo Seiki Seisakusho, product name "Laboplast Mill"). By molding, an EMAA film having a thickness of 80 μm was obtained.

One side of the EMAA film obtained as described above was irradiated with an electron beam under the following conditions. The work processing sheet was prepared in the same manner as in Example 1 except that the EMAA film after the electron beam irradiation was used as a base material and the pressure-sensitive adhesive layer was laminated on the surface of the base material subjected to the electron beam irradiation. Obtained.
Irradiation conditions of electron beam irradiation Irradiation amount: 110 kGy
Number of irradiations: 1 time Cumulative irradiation amount: 110 kGy

[Comparative Example 2]
A work processing sheet was produced in the same manner as in Comparative Example 1 except that the irradiation conditions of electron beam irradiation at the time of producing the base material were changed as follows.
Irradiation conditions of electron beam irradiation Irradiation amount: 110 kGy
Number of irradiations: 2 times Cumulative irradiation amount: 220 kGy

[Test Example 1] (Measurement of crystallinity of base material)
From the base materials prepared in Examples and Comparative Examples, cut pieces of 60 mm × 60 mm were cut out. The cut piece was superposed on an aluminum plate (material: JIS A5052, size: length 60 mm, width 60 mm, thickness 1 mm) having a perfect circular hole with a diameter of 40 mm in the center to prepare a sample for measurement.

Using the obtained measurement sample, wide-angle X-ray diffraction measurement was performed on the positions of the holes on the substrate under the following measurement conditions.
Measurement conditions Wide-angle X-ray diffraction measuring device: SmartLab (RIGAKU)
Measuring range 2θ = 5-40 °, 0.05 steps, measured at room temperature

The profile obtained by the above measurement was waveform-separated into a crystal peak and an amorphous peak, and the area of the crystal peak and the area of the amorphous peak were calculated. Then, the crystallinity (%) was calculated based on the following formula (I). The results obtained are shown in Table 1.
Crystallinity (%) = (crystal peak area) / (crystal peak area + amorphous peak area) x 100 ... (I)

[Test Example 2] (Evaluation of cutting piece suppression)
After peeling the release sheet from the workpiece processing sheet manufactured in Examples and Comparative Examples, the exposed surface of the exposed adhesive layer was formed by using a tape mounter (manufactured by Lintec Corporation, product name "RAD2500 m / 12"). It was affixed to one side of an inch silicon wafer. Subsequently, a dicing ring frame was attached to the peripheral edge of the exposed surface (position not overlapping the silicon wafer) of the workpiece processing sheet. Further, the work processing sheet was cut according to the outer diameter of the ring frame.

Then, the silicon wafer was fragmented into chips having a size of 0.67 mm × 25 mm by dicing under the following dicing conditions using a dicing apparatus (manufactured by Disco Corporation, product name “DFD6362”).
Dicing conditions Wafer thickness: 100 μm
Dicing device: manufactured by Disco Corporation, product name "DFD-6362"
Blade: Both Z1 and Z2 below are manufactured by Disco Corporation Z1: Product name "ZH05-SD3500-N1-50 DF01"
Z2: Product name "ZH05-SD3000-N1-50 ED"
Blade rotation speed Z1: 50,000 rpm
Z2: 35000 rpm
Cutting speed: 100 mm / sec
Blade height Z1: 0.135mm
Z2: 0.055mm
Cutting water volume: 1.0 L / min
Cutting water temperature: 20 ° C

After dicing, the number of cutting pieces was measured by observing the surface of the obtained chip with an electron microscope (manufactured by KEYENCE, product name "VHZ-100", magnification: 300 times). Specifically, 50 dicing lines were observed in each of the MD direction (flow direction during manufacturing of the work processing sheet) and the CD direction (direction perpendicular to the MD direction) of the work processing sheet, and the dicing line was observed. The number of cutting pieces present on the top was measured. Then, the performance of cutting piece suppression was evaluated based on the following criteria. Table 1 shows the number of cutting pieces and the evaluation results.
◯: The number of cutting pieces was 100 or less.
X: The number of cutting pieces was more than 100.

Details of the abbreviations and the like shown in Table 1 are as follows.
Random PP: Random polypropylene resin (manufactured by Prime Polymer Co., Ltd., product name "Prime Polypro E222")
Homo PP: Homo polypropylene resin (manufactured by Prime Polymer Co., Ltd., product name "Prime Polypro E100-GPL")
TPO: Olefin-based thermoplastic elastomer (manufactured by Mitsui Chemicals, product name "Toughmer PN2070", polypropylene component: polyethylene component: butane component = 70:15:15)
AS agent: Antistatic agent (manufactured by Sanyo Chemical Industries, Inc., product name "Perestat")
LDPE: Low density polyethylene (manufactured by Mitsubishi Chemical Corporation, product name "Novatec LL UF442")
EMAA: Ethylene / methacrylic acid copolymer (manufactured by Mitsui / DuPont Polychemical, product name "Nucrel N0903HC")

As is clear from Table 1, the workpiece processing sheet produced in the examples was able to effectively suppress the generation of thread-like cutting pieces during dicing.

The work processing sheet of the present invention can be suitably used for processing a work such as a semiconductor wafer.

1A, 1B, 1C ... Work sheet 11 ... Base material 111a, 111b, 111c, 111d, 111e, 111f ... Resin layer 12 ... Adhesive layer

Claims (10)

A work processing sheet including a base material and an adhesive layer laminated on one side of the base material.
The base material comprises a resin layer formed from a resin composition containing a polyolefin-based resin.
A work processing sheet characterized in that the crystallinity of the base material is 35% or more and 70% or less. The work processing sheet according to claim 1, wherein the proportion of the polyolefin-based resin in the resin composition is 30% by mass or more and 100% by mass or less. The work processing sheet according to claim 1 or 2, wherein the resin composition contains a thermoplastic elastomer other than the polyolefin-based resin. The work processing sheet according to claim 3, wherein the thermoplastic elastomer is an olefin-based elastomer. The work processing sheet according to claim 4, wherein the proportion of the olefin-based elastomer in the resin composition is 1% by mass or more and 50% by mass or less. The work processing sheet according to any one of claims 1 to 5, wherein the base material is composed of the resin layer single layer. The work processing sheet according to any one of claims 1 to 5, wherein the base material is composed of a plurality of layers, and at least one of them is the resin layer. The work processing sheet according to any one of claims 1 to 7, wherein the thickness of the base material is 25 μm or more and 300 μm or less. The work processing sheet according to any one of claims 1 to 8, wherein the pressure-sensitive adhesive layer is composed of an acrylic pressure-sensitive adhesive. The work processing sheet according to any one of claims 1 to 9, wherein the dicing sheet is used.

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