KR20220136042A - Workpiece processing sheet - Google Patents

Abstract

An objective of the present invention is to provide a workpiece processing sheet capable of suppressing occurrence of cutting chips satisfactorily while exhibiting excellent antistatic properties. According to the present invention, the workpiece processing sheet (1) comprises a substrate (11) and an adhesive layer (12). The substrate (11) includes a top layer (111), a back layer (113), and an intermediate layer (112) positioned between the top layer (111) and the back layer (113), at least the back layer (113) contains an antistatic agent, and the intermediate layer (112) contains a styrene-based thermoplastic elastomer. When the loss tangent at 90℃ measured by the viscoelasticity of the substrate (11) at a frequency of 11 Hz is tanδ (90), the loss tangent at 110℃ is tanδ (110), and the loss tangent at 120℃ is tanδ (120), tanδ (110) is 0.25 or more in absolute value, tanδ (110)/tanδ (90) is 1.3 or more, and tanδ (120)/tanδ (110) is 0.9 or less.

Description

Sheet for work processing {WORKPIECE PROCESSING SHEET}

TECHNICAL FIELD The present invention relates to a sheet for processing a workpiece used for processing a workpiece such as a semiconductor wafer.

Semiconductor wafers such as silicon and gallium arsenide and various packages are manufactured in a large-diameter state, cut into chips (dicing), peeled (picked up), and then transferred to the next step, a mounting process. . At this time, the workpiece, such as a semiconductor wafer, is back-grinded, diced, washed, dried, extruded, in a state laminated on an adhesive sheet (hereinafter, sometimes referred to as a "workpiece processing sheet") provided with a base material and an adhesive layer. Processing such as panning, pickup, and mounting is performed.

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

When a large amount of the said thread-shaped cutting pieces adhere to a chip|tip, wire bonding may be inhibited. In addition, if the chip is sealed with a large amount of the thread-like cutting pieces attached to the chip, the cutting pieces are decomposed by the heat of the sealing, and the thermal decomposition product destroys the package or malfunctions in the resulting device. cause of Since this thread-like cutting piece is difficult to remove by washing|cleaning, the yield of a dicing process falls remarkably by generation|occurrence|production of a thread-like cutting piece. Therefore, when performing dicing using the sheet|seat for work processing, it is calculated|required to prevent generation|occurrence|production of a thread-like cutting piece.

In addition, the sheet for work processing is peeled off from the adherend after a predetermined processing step is completed. At this time, static electricity called peeling electrification may be generated between the sheet for work processing and the adherend. Such static electricity causes dust or the like to adhere to a work or device, and also causes destruction of the work or the like. Therefore, antistatic property is also calculated|required of the sheet|seat for work processing.

In Patent Document 1, for the purpose of providing a sheet for work processing having an excellent cutting fragment suppression effect and antistatic property, a predetermined antistatic agent, a predetermined polyolefin-based resin, and a predetermined rubber-like elastic body are blended in a predetermined mixing ratio. A description is disclosed.

Japanese Patent No. 5056112

By the way, generally, after the process of dicing a semiconductor wafer, washing|cleaning of the obtained chip|tip may be performed. Specifically, a sheet for work processing on which a plurality of chips are mounted is adsorbed and fixed to a spinner table, and on the sheet for work processing, cleaning of the chips with ultrapure water and drying (air drying) thereafter are performed. . After these processes were completed, the sheet for work processing on which a plurality of chips were placed was peeled off from the spinner table, but the inventors confirmed that peeling electrification occurred even at the time of this peeling.

Considering the peeling and electrification described above, the conventional sheet for work processing such as in Patent Document 1 cannot be said to have achieved a cutting chip suppression effect and antistatic property at a high level.

The present invention has been made in view of such an actual situation, and an object of the present invention is to provide a sheet for work processing that can favorably suppress the generation of cutting chips while exhibiting excellent antistatic properties.

In order to achieve the above object, first, the present invention provides a sheet for work processing comprising a substrate and an adhesive layer laminated on one side of the substrate, wherein the substrate is proximal to the adhesive layer. a surface layer positioned on the , a back surface layer positioned distally with respect to the pressure-sensitive adhesive layer, and an intermediate layer positioned between the surface layer and the back surface layer, wherein at least the back surface layer contains an antistatic agent, The intermediate layer contains a styrenic thermoplastic elastomer, and the loss tangent at 90° C. is tanδ (90), and the loss tangent at 110° C. is tanδ (110), and at 120° C. When the loss tangent to is tanδ(120), tanδ(110) is 0.25 or more in absolute value, tanδ(110)/tanδ(90) is 1.3 or more, and tanδ(120)/tanδ(110) is 0.9 or less. To provide a sheet for processing a workpiece characterized in (Invention 1).

In the invention (Invention 1), at least the back layer contains an antistatic agent, so that it has excellent antistatic properties. In addition, since the intermediate layer contains a styrenic thermoplastic elastomer and the base material has the above-mentioned viscoelastic properties, generation of cutting chips during dicing can be suppressed favorably, and chips obtained by dicing can be picked up. The pick-up property at the time of can be kept favorable. In addition, especially when the intermediate layer contains a styrenic thermoplastic elastomer, the intermediate layer is difficult to melt at a high temperature, so that when the dicing blade reaches the intermediate layer, the generation of chips from the intermediate layer can be suppressed favorably.

In the said invention (invention 1), it is preferable that the said surface layer contains the antistatic agent (invention 2).

In the said invention (invention 1, 2), it is preferable that the said surface layer contains a polyolefin resin and an olefinic thermoplastic elastomer (invention 3).

In the above inventions (Inventions 1 to 3), it is preferable that the back layer contains an olefinic thermoplastic elastomer (Invention 4).

In the said inventions (Inventions 1-4), it is preferable that the said intermediate|middle layer contains a styrenic thermoplastic elastomer, a polyolefin resin, and an olefinic thermoplastic elastomer (Invention 5).

In the above inventions (Inventions 1 to 5), the intermediate layer does not contain an antistatic agent, or the intermediate layer contains an antistatic agent in a content (unit: mass %) smaller than each of the surface layer and the back surface layer. It is preferable to contain (invention 6).

In the said invention (invention 1-6), it is preferable that the said antistatic agent is a polymer type antistatic agent (invention 7).

In the said invention (invention 1-7), it is preferable that the surface resistivity of the surface on the opposite side to the base material in the said adhesive layer is 1.0x10 ¹³ ohm/square or less (invention 8).

In the said invention (Inventions 1-8), it is preferable that it is a dicing sheet (Invention 9).

The sheet for work processing according to the present invention can suppress generation of cutting chips favorably while exhibiting excellent antistatic properties.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of the sheet|seat for a workpiece|work which concerns on one Embodiment of this invention.

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

1 shows a cross-sectional view of a sheet for work processing according to an embodiment of the present invention. The sheet|seat 1 for a work process shown in FIG. 1 is equipped with the base material 11 and the adhesive layer 12 laminated|stacked on the single side|surface side in the base material 11. As shown in FIG.

As shown in FIG. 1 , the substrate 11 includes a surface layer 111 located proximal to the pressure-sensitive adhesive layer 12 , a back surface layer 113 located distal to the pressure-sensitive adhesive layer 12 , and a surface layer. An intermediate layer 112 positioned between (111) and the back surface layer 113 is provided.

In the sheet 1 for work processing according to the present embodiment, at least the back surface layer 113 contains an antistatic agent, and the intermediate layer 112 contains a styrenic thermoplastic elastomer. Then, the loss tangent at 90°C measured in viscoelasticity with respect to the substrate 11 at a frequency of 11 Hz is tanδ(90), the loss tangent at 110°C is tanδ(110), and the loss tangent at 120°C is tanδ(120) , tanδ(110) is 0.25 or more in absolute value, tanδ(110)/tanδ(90) is 1.3 or more, and tanδ(120)/tanδ(110) is 0.9 or less. Hereinafter, the physical properties related to these loss tangents may be referred to as "viscoelastic physical properties". In addition, the specific measuring method of the loss tangent in this specification is as showing in the test example mentioned later.

The sheet 1 for work processing according to the present embodiment has excellent antistatic properties because at least the back surface layer 113 contains an antistatic agent. Therefore, peeling electrification at the time of isolate|separating a peeling sheet and a workpiece|work from the sheet|seat 1 for a workpiece|work processing can be suppressed favorably. Furthermore, peeling and electrification when the sheet 1 for work processing is removed from the spinner table after washing and drying of the workpiece on the sheet 1 for workpiece processing can be prevented favorably.

Further, in the sheet 1 for work processing according to the present embodiment, the intermediate layer 112 contains a styrenic thermoplastic elastomer, and the substrate 11 has the above-mentioned viscoelastic physical properties. While being able to suppress generation|occurrence|production favorably, the pick-up property at the time of picking up the chip|tip obtained by dicing can be maintained favorably. In particular, the substrate 11 satisfying the above viscoelastic properties exhibits a peak of loss tangent tanδ in a temperature range of 90 to 120°C. That is, up to this temperature range, since a part of the base material 11 is in a glass state, it is difficult to melt the base material 11 due to frictional heat generated during dicing, and excellent cutting resistance is obtained. In particular, when the intermediate layer 112 contains a styrenic thermoplastic elastomer, the intermediate layer 112 is difficult to melt at a high temperature. generation of cutting fragments can be favorably suppressed.

From the viewpoint of the cutting fragment suppression effect, the tan δ (110) (absolute value) is 0.25 or more, preferably 0.3 or more, particularly preferably 0.32 or more, and further preferably 0.34 or more. The upper limit of the tan δ (110) (absolute value) is preferably 0.5 or less, particularly preferably 0.45 or less, and further preferably 0.4 or less from the viewpoint of pick-up and expandability of the sheet for work processing.

From the viewpoint of the cutting fragment suppression effect, the tan δ (110)/tan δ (90) is 1.3 or more, preferably 1.4 or more, particularly preferably 1.5 or more, and further preferably 1.6 or more. The upper limit of tan δ (110)/tan δ (90) is preferably 2.5 or less, particularly preferably 2.3 or less, and further preferably 1.9 or less from the viewpoint of pick-up and expandability of the sheet for work processing.

From the viewpoint of the cutting fragment suppression effect, the tan δ (120)/tan δ (110) is 0.9 or less, preferably 0.88 or less, and particularly preferably 0.85 or less. The lower limit of tan δ (120)/tan δ (110) is preferably 0.4 or more, particularly preferably 0.5 or more, and further preferably 0.6 or more from the viewpoints of the pick-up property and expandability of the sheet for work processing.

The tan δ (90) (absolute value) is preferably 0.15 or more, particularly preferably 0.17 or more, and further preferably 0.19 or more. The tan δ (90) (absolute value) is preferably 0.4 or less, particularly preferably 0.3 or less, and further preferably 0.23 or less. When the tan δ (90) is in the above range, the viscoelastic physical properties described above are easily satisfied.

The tan δ (120) (absolute value) is preferably 0.2 or more. Moreover, it is preferable that the said tan δ (120) (absolute value) is 0.4 or less, and it is especially preferable that it is 0.3 or less. When the tan δ (120) is in the above range, the above-described viscoelastic properties are easily satisfied.

1. Composition of sheet for workpiece processing

1-1. write

The base material 11 in this embodiment is provided with the surface layer 111, the intermediate|middle layer 112, and the back surface layer 113, as mentioned above.

(1) middle layer

In the present embodiment, the intermediate layer 112 contains a styrenic thermoplastic elastomer (hereinafter, sometimes referred to as a “styrenic elastomer”). A styrenic elastomer is a copolymer containing a structural unit derived from styrene or a derivative (styrene-based compound) thereof, and is a material having rubber-like elasticity and thermoplasticity in a temperature range including room temperature.

Examples of the styrene-based elastomer include a styrene-conjugated diene copolymer and a styrene-olefin copolymer, and among these, a styrene-conjugated diene copolymer is preferable. Specific examples of the styrene-conjugated diene copolymer include a styrene-butadiene copolymer, a styrene-butadiene-styrene copolymer (SBS), a styrene-butadiene-butylene-styrene copolymer, a styrene-isoprene copolymer, and a styrene-isoprene-styrene copolymer. unhydrogenated styrene-conjugated diene copolymers such as a copolymer (SIS) and a styrene-ethylene-isoprene-styrene copolymer; Hydrogenated styrene such as styrene-ethylene/propylene-styrene copolymer (SEPS: hydrogenated product of styrene-isoprene-styrene copolymer) and styrene-ethylene-butylene-styrene copolymer (SEBS: hydrogenated product of styrene-butadiene copolymer) -conjugated diene copolymer etc. are mentioned. The styrenic thermoplastic elastomer may be a hydrogenated substance (hydrogenated substance) or an unhydrogenated substance, but is preferably a hydrogenated substance. Among the above, a hydrogenated styrene-conjugated diene copolymer is preferable, and a styrene-ethylene-butylene-styrene copolymer (SEBS) is particularly preferable from the viewpoint of the effect of suppressing cutting fragments and from the viewpoint of easily achieving the above-described viscoelastic properties. .

The content of the structural unit derived from styrene or a styrene-based compound in the styrene-based elastomer is preferably 10% by mass or more, particularly preferably 15% by mass or more, and further preferably 20% by mass or more. Thereby, the cutting-fragment suppression effect becomes more excellent, and it becomes easy to achieve the above-mentioned viscoelastic physical property more. Further, the content of the structural unit is preferably 50 mass % or less, particularly preferably 45 mass % or less, and further preferably 40 mass % or less from the viewpoint of pick-up properties and expandability of the sheet for work processing.

It is preferable that content of the styrene-type elastomer in the intermediate|middle layer 112 is 10 mass % or more, It is especially preferable that it is 15 mass % or more, Furthermore, it is preferable that it is 20 mass % or more. Moreover, it is preferable that the said content is 50 mass % or less, It is especially preferable that it is 45 mass % or less, Furthermore, it is preferable that it is 40 mass % or less. When the content of the styrene-based elastomer in the intermediate layer 112 is within the above range, the cutting chip suppression effect is more excellent, and the above-described viscoelastic properties are more easily achieved.

The intermediate layer 112 preferably contains a thermoplastic elastomer other than a styrenic elastomer. Examples of the thermoplastic elastomer include an olefin-based thermoplastic elastomer, a rubber-based thermoplastic elastomer, a urethane-based thermoplastic elastomer, an acrylic thermoplastic elastomer, and a vinyl chloride-based thermoplastic elastomer. These may be used independently and may be used in combination of 2 or more type.

Among the above-mentioned thermoplastic elastomers, an olefinic thermoplastic elastomer (hereinafter, sometimes referred to as "olefinic elastomer") is preferable from a viewpoint of being easy to acquire a favorable cutting-fragment suppression effect. In addition, "olefin-based elastomer" is a copolymer containing a structural unit derived from an olefin or its derivative (olefin-based compound), and is a material having rubber-like elasticity in a temperature range including room temperature and thermoplasticity. to be.

Examples of the olefin elastomer include ethylene/propylene copolymer, ethylene/α-olefin copolymer, propylene/α-olefin copolymer, butene/α-olefin copolymer, ethylene/propylene/α-olefin copolymer, ethylene/butene/ and those containing at least one resin selected from the group consisting of an α-olefin copolymer, a propylene/butene/α-olefin copolymer, and an ethylene/propylene/butene/α-olefin copolymer. Among these, an ethylene-propylene copolymer is preferable.

It is preferable that content of the olefin type elastomer in the intermediate|middle layer 112 is 30 mass % or more, It is especially preferable that it is 35 mass % or more, Furthermore, it is preferable that it is 40 mass % or more. Moreover, it is preferable that the said content is 60 mass % or less, It is especially preferable that it is 55 mass % or less, Furthermore, it is preferable that it is 50 mass % or less. When the content of the olefin-based elastomer in the intermediate layer 112 is within the above range, the cutting-fragment suppression effect becomes more excellent, and the above-described viscoelastic physical properties can be more easily achieved.

It is preferable that the intermediate|middle layer 112 contains polyolefin resin other than the above-mentioned thermoplastic elastomer. By containing polyolefin-type resin, it is excellent in the point of the film-forming property at the time of film forming, and chipping suppression. In addition, in this specification, a polyolefin resin is a homopolymer or copolymer which uses an olefin as a monomer, or a copolymer which uses an olefin and molecules other than an olefin as a monomer, The part based on the olefin unit in the resin after polymerization. refers to a resin having a mass ratio of 1.0% by mass or more.

The polyolefin-based resin is not particularly limited as long as a desired effect is obtained without impairing the above-described viscoelastic physical properties. The polymer|macromolecule which comprises polyolefin resin may be linear, and may have a side chain. Moreover, the said polymer|macromolecule may have an aromatic ring and an aliphatic ring.

Examples of the olefin monomer constituting the polyolefin-based 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. decene and the like are exemplified. Examples of the olefin monomer having a cyclic structure include norbornene, cyclopentadiene, cyclohexadiene, dicyclopentadiene and tetracyclododecene, and derivatives thereof.

Polyolefin resin can be used individually by 1 type or in mixture of 2 or more types.

It is preferable to use at least one of the polyethylene which contains ethylene as a main polymerization unit, and the polypropylene which contains propylene as a main polymerization unit among the specific examples of the polyolefin resin mentioned above.

As said polypropylene, generally, a homo polypropylene, a random polypropylene, and a block polypropylene are mentioned. These can be used individually by 1 type or in mixture of 2 or more types. In this embodiment, it is preferable to use random polypropylene from a viewpoint of expandability.

When the polyolefin 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, or a mixture of two or more thereof.

It is preferable that content of the polyolefin resin in the intermediate|middle layer 112 is 15 mass % or more, It is especially preferable that it is 20 mass % or more, Furthermore, it is preferable that it is 25 mass % or more. Thereby, it is excellent in film forming property at the time of film forming. Moreover, it is preferable that the said content is 45 mass % or less, It is especially preferable that it is 40 mass % or less, Furthermore, it is preferable that it is 35 mass % or less. Thereby, it becomes easier to achieve the above-mentioned viscoelastic physical property.

Here, although the intermediate|middle layer 112 may also contain an antistatic agent, from a viewpoint of being easy to suppress generation|occurrence|production of a cutting piece, it is preferable that the intermediate|middle layer 112 does not contain an antistatic agent. When the intermediate layer 112 contains an antistatic agent, the intermediate layer 112 preferably contains an antistatic agent in a content (unit: mass%) smaller than that of the back surface layer 113 (and the surface layer 111 ). Specifically, in the intermediate layer 112, it is preferable that the content is less than 5 mass %, It is more preferable that it is less than 3 mass %, It is especially preferable that it is less than 1 mass %, It is most preferable that it is 0 mass %. When the intermediate|middle layer 112 contains an antistatic agent, the lower limit of the content is 0.01 mass % or more, for example. The present inventors have discovered that an antistatic agent causes the generation of chips during dicing, but as described above, the intermediate layer 112 that does not contain an antistatic agent or has a small content is the surface layer 111 (preferably). (preferably under a thin layer), the occurrence of cutting chips can be significantly reduced compared to the case where the entire substrate contains an antistatic agent.

The intermediate layer 112 may contain components other than the above-mentioned components, for example, components used for the base material of a general sheet|seat for a work process. Examples of such components include various additives such as a flame retardant, a plasticizer, a lubricant, an antioxidant, a colorant, an infrared absorber, an ultraviolet absorber, and an ion scavenger. Although it does not specifically limit as content of these additives, It is preferable to set it as the range in which the intermediate|middle layer 112 exhibits a desired function.

(2) back layer

In this embodiment, the back surface layer 113 contains an antistatic agent. Thereby, excellent antistatic property is obtained. On the other hand, as described above, the antistatic agent causes the generation of chips during dicing, but usually, the dicing blade does not reach the back layer 113, so even if the back layer 113 contains the antistatic agent. , it does not cause cutting chips.

The antistatic agent in this embodiment is not specifically limited, A well-known thing can be used. Examples of the antistatic agent include a low molecular antistatic agent and a high molecular antistatic agent. From a viewpoint of being hard to produce, a polymer type antistatic agent is preferable.

Examples of the polymer-type antistatic agent include copolymers having polyether units such as polyether esteramide and polyether polyolefin block copolymer, and these copolymers include metal salts such as alkali metal salts and alkaline earth metal salts, and ionic liquids. it may be

It is preferable that content of the antistatic agent in the back surface layer 113 is 10 mass % or more, It is especially preferable that it is 20 mass % or more, Furthermore, it is preferable that it is 30 mass % or more. Thereby, it becomes a thing easy to exhibit favorable antistatic property. Moreover, it is preferable that the said content is 50 mass % or less, It is especially preferable that it is 45 mass % or less, Furthermore, it is preferable that it is 40 mass % or less. Thereby, it becomes easier to achieve the above-mentioned viscoelastic physical property.

The material other than the antistatic agent constituting the back layer 113 is not particularly limited as long as the above-described viscoelastic properties are satisfied, but it is preferable to contain at least a thermoplastic elastomer and further contain a polyolefin-based resin if desired. According to these components, it becomes easy to satisfy|fill the above-mentioned viscoelastic physical properties. Moreover, the thermoplastic elastomer has an effect|action which makes the pick-up property favorable.

As the thermoplastic elastomer, those exemplified in the intermediate layer 112 can be used, and among them, an olefin-based elastomer is preferable.

The content of the olefinic elastomer in the back layer 113 is preferably 30 mass % or more, particularly preferably 35 mass % or more, and further preferably 40 mass % or more. Moreover, it is preferable that the said content is 80 mass % or less, and it is especially preferable that it is 75 mass % or less. When the content of the olefin-based elastomer in the back surface layer 113 is within the above range, the above-described viscoelastic properties can be more easily achieved.

In addition, it is preferable that the back surface layer 113 is a thermoplastic elastomer and does not contain a styrenic elastomer. When a styrenic elastomer is contained, it may raise|generate blocking at the time of film forming, or may affect pick-up property. Even if the back surface layer 113 contains a styrenic elastomer, the content is preferably 3% by mass or less, particularly preferably 2% by mass or less, and more preferably 1% by mass or less.

When the back surface layer 113 contains a polyolefin resin, the effect that it is excellent in film forming property at the time of film forming is acquired. As the polyolefin-based resin, those exemplified in the intermediate layer 112 can be used, and among them, polypropylene, particularly random polypropylene, is preferably used.

When the back layer 113 contains a polyolefin resin, the content thereof is preferably 10 mass % or more, particularly preferably 15 mass % or more, and further 20 mass % or more from the viewpoint of excellent film forming properties at the time of film forming. % or more is preferable. Moreover, it is preferable that the said content is 40 mass % or less from a viewpoint of pick-up property, It is especially preferable that it is 35 mass % or less, Furthermore, it is preferable that it is 30 mass % or less.

Like the intermediate layer 112, the back surface layer 113 may contain components other than the above-mentioned components, for example, components used for the base material of a general sheet for work processing.

(3) surface layer

In the sheet 1 for work processing according to the present embodiment, at least the back surface layer 113 contains an antistatic agent, but preferably the surface layer 111 also contains an antistatic agent. Thereby, the antistatic property becomes more excellent. As described above, the antistatic agent causes the generation of chips during dicing, but by reducing the thickness of the surface layer 111 and eliminating or reducing the content of the antistatic agent in the intermediate layer 112, the entire substrate is Compared to the case where an antistatic agent is contained, the occurrence of cutting chips can be significantly reduced.

As the antistatic agent in the front layer 111 , the same antistatic agent as in the back layer 113 can be used.

It is preferable that content of the antistatic agent in the surface layer 111 is 3 mass % or more, It is especially preferable that it is 5 mass % or more, Furthermore, it is preferable that it is 10 mass % or more. Thereby, the antistatic property becomes more excellent. Moreover, it is preferable that the said content is 40 mass % or less, It is especially preferable that it is 35 mass % or less, Furthermore, it is preferable that it is 30 mass % or less. Thereby, generation|occurrence|production of a cutting fragment can be suppressed low.

The material other than the antistatic agent constituting the surface layer 111 is not particularly limited as long as the above-described viscoelastic properties are satisfied, but it is preferable to contain at least a thermoplastic elastomer, and it is particularly preferable to further contain a polyolefin resin. According to these components, it becomes easy to satisfy|fill the above-mentioned viscoelastic physical properties. Moreover, the thermoplastic elastomer has an effect|action which makes the pick-up property favorable.

As the thermoplastic elastomer and polyolefin resin, those exemplified in the intermediate layer 112 and the back surface layer 113 can be used. As the thermoplastic elastomer, an olefin-based elastomer is preferable.

It is preferable that content of the olefin type elastomer in the surface layer 111 is 30 mass % or more, It is especially preferable that it is 35 mass % or more, Furthermore, it is preferable that it is 40 mass % or more. Moreover, it is preferable that the said content is 80 mass % or less, It is especially preferable that it is 75 mass % or less, Furthermore, it is preferable that it is 50 mass % or less. When the content of the olefin-based elastomer in the surface layer 111 is within the above range, the above-described viscoelastic physical properties can be more easily achieved.

Moreover, like the back layer 113, the surface layer 111 is a thermoplastic elastomer, and it is preferable not to contain a styrenic elastomer. In addition, even if the surface layer 111 contains a styrenic elastomer, it is preferable to make the content into the same amount as the amount exemplified by the back surface layer 113 .

The content of the polyolefin-based resin in the surface layer 111 is preferably 10 mass % or more, particularly preferably 15 mass % or more, and further preferably 20 mass % or more from the viewpoint of excellent film forming properties at the time of film forming. do. Moreover, it is preferable that the said content is 45 mass % or less from a pick-up property viewpoint, It is especially preferable that it is 40 mass % or less, Furthermore, it is preferable that it is 35 mass % or less.

It is also preferable that the surface layer 111 contains an acid-modified resin as a component other than the above. In this specification, "acid-modified resin" means that the structure derived from an acidic component was added to the polymer chain. The structure derived from an acidic component may be in the form of an acid anhydride, and may have a carboxy group. When the surface layer 111 contains the acid-modified resin as described above, the adhesion between the substrate 11 and the pressure-sensitive adhesive layer 12 is improved, and it is possible to suppress that the pressure-sensitive adhesive remains on the chip side at the time of pickup.

Examples of the main chain of the acid-modified resin include ethylene-acrylic copolymers such as ethylene-(meth)acrylic acid copolymer and ethylene-(meth)acrylic acid ester copolymer. According to this resin, while improving the adhesiveness of the surface layer 111 and the adhesive layer 12, it is easy to satisfy|fill the above-mentioned viscoelastic physical property. In addition, in this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. The same is true for other similar terms.

As said (meth)acrylic acid ester, C1-C4 (meth)acrylic acid alkylester of an alkyl group is preferable. For example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, (meth)acrylate n-butyl, etc. are mentioned preferably. Among them, ethyl (meth)acrylate is more preferable, and ethyl acrylate is particularly preferable.

It is preferable that content of the structure derived from (meth)acrylic acid ester in an ethylene- (meth)acrylic acid ester copolymer is 1 mass % or more, and it is especially preferable that it is 3 mass % or more. Moreover, it is preferable that the said content is 20 mass % or less, It is especially preferable that it is 15 mass % or less, Furthermore, it is preferable that it is 10 mass % or less. When the said content exists in said range, it becomes easy to satisfy|fill the above-mentioned viscoelastic physical property.

In order to acid-modify resin, it is preferable to make resin react with unsaturated carboxylic acid. Examples of the unsaturated carboxylic acid include maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, aconitic acid, maleic anhydride, itaconic anhydride, glutaconic acid anhydride, citraconic acid anhydride. , aconitic anhydride, norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride, and the like. These can be used individually by 1 type or in combination of 2 or more type. Among the above, the viewpoint of adhesiveness with the adhesive layer 12 to maleic anhydride is especially preferable.

It is preferable that it is 1 mass % or more, and, as for the acid content (quantity of the structure originating in an acid component) in the said acid-modified resin, it is especially preferable that it is 2 mass % or more. Moreover, it is preferable that the said acidic content is 7 mass % or less, and it is especially preferable that it is 5 mass % or less. When the amount of the acidic content is in the above range, the adhesion between the surface layer 111 and the pressure-sensitive adhesive layer 12 is further improved.

When the surface layer 111 contains an acid-modified resin, it is preferable that content of the acid-modified resin in the surface layer 111 is 5 mass % or more, and it is especially preferable that it is 10 mass % or more. Thereby, the adhesiveness of the surface layer 111 and the adhesive layer 12 improves more. Moreover, it is preferable that the said content is 30 mass % or less, It is especially preferable that it is 25 mass % or less, Furthermore, it is preferable that it is 20 mass % or less. Thereby, the above-described viscoelastic properties are easily satisfied.

Like the intermediate layer 112 and the back surface layer 113, the surface layer 111 may contain components other than the above-mentioned components, for example, components used for the base material of a general sheet for work processing.

(4) Surface treatment of the substrate

On the surface of the base material 11 on which the pressure-sensitive adhesive layer 12 is laminated, in order to improve adhesion with the pressure-sensitive adhesive layer 12, a surface such as a primer treatment, a corona treatment, a plasma treatment, a roughening treatment (matte treatment), etc. A process may be performed. As a roughening process, the embossing method, the sand blasting method, etc. are mentioned, for example. Among these, it is preferable to perform corona treatment.

(5) Preparation of substrate

The manufacturing method of the base material 11 in this embodiment is not specifically limited, For example, Melt-extrusion methods, such as a T-die method and a ring-die method; calendar method; A solution method such as a dry method or a wet method can be used. Among these, it is preferable to employ|adopt a melt extrusion method from a viewpoint of efficiently manufacturing a base material, and it is especially preferable to employ|adopt a T-die method.

In addition, when manufacturing the base material 11 by the melt extrusion method, each of the components constituting each layer is kneaded, directly from the kneaded product obtained, or after producing a pellet once, using a known extruder, a plurality of layers can be simultaneously extruded (co-extruded) to form a film.

(6) Physical properties of the substrate, etc.

(6-1) thickness

It is preferable that the thickness of the surface layer 111 in this embodiment is 10 micrometers or less, It is especially preferable that it is 8 micrometers or less, Furthermore, it is preferable that it is 4 micrometers or less. As described above, since the thickness of the surface layer 111 located proximally with respect to the pressure-sensitive adhesive layer 12 is small, even if the surface layer 111 contains an antistatic agent, desired antistatic properties are exhibited and the generation of chips is good. can be suppressed.

The thickness of the surface layer 111 is preferably 1 µm or more, particularly preferably 2 µm or more, and more preferably 3 µm or more. Thereby, when the surface layer 111 contains an antistatic agent, it becomes easy to exhibit antistatic property favorably. Moreover, when the surface layer 111 contains acid-modified resin, adhesiveness with the adhesive layer 12 becomes more excellent.

It is preferable that the thickness of the intermediate|middle layer 112 in this embodiment is 40 micrometers or more, It is especially preferable that it is 50 micrometers or more, Furthermore, it is preferable that it is 60 micrometers or more. Thereby, the above-mentioned viscoelastic physical properties are easily satisfied, and it becomes easy to suppress generation|occurrence|production of a cutting chip. Moreover, the sheet|seat 1 for a workpiece|work processing becomes a thing easy to have moderate intensity|strength, and it becomes easy to support favorably the workpiece|work fixed on the sheet|seat 1 for a workpiece|work processing. The thickness of the intermediate layer 112 is preferably 100 µm or less, particularly preferably 90 µm or less, and more preferably 80 µm or less. Thereby, the above-mentioned viscoelastic physical properties are easily satisfied.

The thickness of the back surface layer 113 in the present embodiment is preferably 2 µm or more, particularly preferably 4 µm or more, and more preferably 8 µm or more. Thereby, the antistatic property of the sheet|seat 1 for a workpiece|work processing becomes more excellent. The thickness of the back surface layer 113 is preferably 40 µm or less, particularly preferably 30 µm or less, and further preferably 25 µm or less. Thereby, the above-mentioned viscoelastic physical properties are easily satisfied.

It is preferable that the overall thickness of the base material 11 in this embodiment is 50 micrometers or more, It is especially preferable that it is 60 micrometers or more, Furthermore, it is preferable that it is 70 micrometers or more. Moreover, it is preferable that the said thickness is 140 micrometers or less, It is especially preferable that it is 120 micrometers or less, Furthermore, it is preferable that it is 100 micrometers or less. When the overall thickness of the base material 11 is within the above range, the above-described viscoelastic physical properties can be easily satisfied, and it is easy to favorably support the work fixed on the sheet 1 for work processing.

(6-2) Surface resistivity

The surface resistivity of the surface on the surface layer 111 side of the substrate 11 is preferably 1.0×10 ¹³ Ω/□ or less, particularly preferably 1.0×10 ¹² Ω/□ or less, and furthermore, 1.0×10 ¹¹ or less. It is preferable that it is Ω/□ or less. Thereby, the sheet|seat 1 for work processing which concerns on this embodiment can exhibit the outstanding antistatic property. Moreover, the lower limit of the said surface resistivity is not specifically limited, For example, 1.0x10 ⁸ ohm/square or more may be sufficient, and especially 1.0x10 ⁹ ohm/square or more may be sufficient. The detail of the measuring method of the surface resistivity in this specification is as having described in the test example mentioned later.

1-2. adhesive layer

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 12 in the present embodiment is not particularly limited as long as it can exhibit sufficient adhesive force to the adherend (particularly, relative work adhesive force sufficient for processing the work). Examples of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 12 include an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a polyester pressure-sensitive adhesive, and a polyvinyl ether pressure-sensitive adhesive. Among these, it is preferable to use an acrylic adhesive from a viewpoint of being easy to exhibit desired adhesive force.

Although the adhesive which does not have active energy ray sclerosis|hardenability may be sufficient as the adhesive which comprises the adhesive layer 12 in this embodiment, the adhesive (henceforth "active energy ray-curable adhesive") which has active energy ray sclerosis|hardenability. ) is preferred. 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 adhesive force of the sheet 1 for work processing to an adherend can be easily reduced. have. In particular, it becomes possible to isolate|separate the workpiece|work after a process from the said sheet|seat 1 for a workpiece|work easily by irradiation of an active energy ray.

The active energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 12 may include a polymer having active energy ray curability as a main component, and at least one active energy ray non-curable polymer (polymer not having active energy ray curability) and at least one What has as a main component the mixture with the monomer and/or oligomer which has the above active energy ray-curable group may be sufficient. Moreover, the mixture of the polymer which has active energy ray hardenability, and the monomer and/or oligomer which has an at least 1 or more active energy ray-curable group may be sufficient as an active energy ray-curable adhesive.

The 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 sometimes referred to as "active energy ray curable polymer") It is preferable to be It is preferable that this active energy ray-curable polymer is a thing obtained by making the acrylic polymer which has a functional group containing monomer unit react, and the unsaturated group containing compound which has the functional group couple|bonded with the functional group. In addition, in this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. The same is true for other similar terms. In addition, the concept of "copolymer" shall also be included in "polymer".

The acrylic polymer having the aforementioned functional group-containing monomer unit may be formed by polymerizing other monomers together with the functional group-containing monomer. As these functional group-containing monomers and other monomers, and the above-mentioned unsaturated group-containing compounds, well-known ones can be used, for example, those disclosed in International Publication No. 2018/084021 can be used.

It is preferable that the weight average molecular weight of the said active energy ray-curable polymer is 10,000 or more, It is especially preferable that it is 150,000 or more, Furthermore, it is 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, 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).

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

It is preferable that the weight average molecular weight of the acrylic polymer as said active energy ray non-curable polymer component is 10,000 or more, It is especially preferable that it is 150,000 or more, Furthermore, it is 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, it is especially preferable that it is 1 million or less.

Moreover, as a monomer and/or an oligomer which has at least 1 or more active energy ray-curable group mentioned above, the ester of polyhydric alcohol and (meth)acrylic acid, etc. can be used, for example.

Moreover, when using an ultraviolet-ray as an active energy ray for hardening an active energy ray-curable adhesive, it is preferable to add a photoinitiator with respect to the said adhesive. Moreover, you may add an active energy ray non-curable polymer component or an oligomer component, a crosslinking agent, etc. to the said adhesive.

It is preferable that it is 1 micrometer or more, and, as for the thickness of the adhesive layer 12 in this embodiment, it is especially preferable that it is 3 micrometers or more, Furthermore, it is preferable that it is 5 micrometers or more. Moreover, it is preferable that the thickness of the adhesive layer 12 is 70 micrometers or less, It is especially preferable that it is 30 micrometers or less, Furthermore, it is preferable that it is 15 micrometers or less. When the thickness of the pressure-sensitive adhesive layer 12 is within the above-described range, the sheet 1 for a work processing according to the present embodiment tends to exhibit desired adhesiveness.

1-3. release sheet

In the sheet 1 for work processing according to the present embodiment, the surface (hereinafter, sometimes referred to as "adhesive surface") on the opposite side to the base material 11 in the pressure-sensitive adhesive layer 12 is adhered to the work. During the period, a release sheet may be laminated on the surface for the purpose of protecting the surface.

The structure of the said 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 said releasing agent, a silicone type, a fluorine type, a long-chain alkyl type, etc. can be used, Among these, the silicone type from which the stable performance is obtained is preferable.

There is no restriction|limiting in particular about the thickness of the said peeling sheet, For example, 16 micrometers or more and 250 micrometers or less may be sufficient.

1-4. etc

In the sheet|seat 1 for a work process which concerns on this embodiment, the adhesive bond layer may be laminated|stacked on the surface on the opposite side to the base material 11 in the adhesive layer 12. As shown in FIG. In this case, the sheet|seat 1 for work processing which concerns on this embodiment can be used as a dicing die-bonding sheet|seat. In the said sheet, the chip|tip in which the adhesive bond layer divided into pieces was laminated|stacked can be obtained by affixing a workpiece|work to the surface on the opposite side to the adhesive layer 12 in the adhesive bond layer, and dicing the adhesive bond layer together with the said workpiece|work. The chip can be easily fixed to a target on which the chip is mounted by the separated adhesive layer. As a material constituting the adhesive layer described above, it is preferable to use a material containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, or a material containing a B-stage (semi-cured shape) thermosetting adhesive component.

In addition, in the sheet|seat 1 for a work process which concerns on this embodiment, the protective film forming layer may be laminated|stacked on the adhesive surface in the adhesive layer 12. As shown in FIG. In this case, the sheet 1 for work processing according to the present embodiment can be used as a sheet for forming a protective film and for dicing. In such a sheet, by affixing a work on the surface opposite to the pressure-sensitive adhesive layer 12 in the protective film forming layer, and dicing the protective film forming layer together with the work, a chip in which the separate protective film forming layer is laminated can be obtained. It is preferable to use the thing in which the circuit was formed in one side as this work, and in this case, a protective film forming layer is laminated|stacked on the surface on the opposite side to the surface in which the said circuit was formed normally. By hardening the separated protective film forming layer at a predetermined timing, a protective film having sufficient durability can be formed into a chip. It is preferable that a protective film forming layer consists of an uncured curable adhesive agent.

2. Physical properties of sheet for workpiece processing

In the sheet 1 for work processing according to the present embodiment, the surface resistivity of the surface (adhesive surface) on the opposite side to the substrate 11 in the pressure-sensitive adhesive layer 12 is preferably 1.0×10 ¹³ Ω/□ or less, In particular, it is preferably 1.0×10 ¹² Ω/square or less, and more preferably 1.0×10 ¹¹ Ω/square or less. Accordingly, the sheet 1 for work processing according to the present embodiment can have excellent antistatic properties. Moreover, the lower limit of the said surface resistivity is not specifically limited, For example, 1.0x10 ⁸ ohm/square or more may be sufficient, and especially 1.0x10 ⁹ ohm/square or more may be sufficient. Moreover, when the adhesive layer 12 is active energy ray sclerosis|hardenability, let the said surface resistivity be the value after irradiating an active energy ray with respect to the adhesive layer 12, and hardening the said adhesive layer 12.

3. Manufacturing method of sheet for work processing

The manufacturing method of the sheet|seat 1 for a work process which concerns on this embodiment is not specifically limited. For example, after forming the adhesive layer 12 on a release sheet, the surface on the side of the surface layer 111 in the base material 11 is applied to the surface on the opposite side to the release sheet in the said adhesive layer 12. It is preferable to obtain the sheet|seat 1 for work processing by laminating|stacking.

Formation of the adhesive layer 12 mentioned above can be performed by a well-known method. For example, the adhesive composition for forming the adhesive layer 12, and the coating liquid which further contains a solvent or a dispersion medium as needed are prepared. And the said coating liquid is apply|coated to the surface (Hereinafter, it may be called "peelable surface") which has peelability of a peeling sheet. Then, the adhesive layer 12 can be formed by drying the obtained coating film.

Application of the above-mentioned coating liquid can be performed 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, etc. can be performed. Moreover, the property is not specifically limited as long as it can apply|coat, and the coating liquid may contain the component for forming the adhesive layer 12 as a solute, and may contain it as a dispersoid. . In addition, the peeling sheet may peel as a process material, and may protect the adhesive layer 12 until it sticks to a to-be-adhered body.

When the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 12 contains the above-mentioned crosslinking agent, by changing the above drying conditions (temperature, time, etc.) or by separately providing heat treatment, the polymer component in the coating film and the crosslinking agent It is preferable to advance the crosslinking reaction with and to form a crosslinked structure with a desired density in the pressure-sensitive adhesive layer 12 . In addition, in order to sufficiently advance the crosslinking reaction described above, after bonding the pressure-sensitive adhesive layer 12 and the substrate 11 together, for example, curing such as standing still in an environment of 23° C. and 50% relative humidity for several days is performed. do.

4. How to use the sheet for work processing

The sheet 1 for processing a workpiece according to the present embodiment can be used for processing a workpiece such as a semiconductor wafer. That is, after affixing the adhesive surface of the sheet|seat 1 for a workpiece|work processing which concerns on this embodiment to a workpiece|work, a workpiece|work can be processed on the sheet|seat 1 for a workpiece|work processing. According to the processing, the sheet 1 for work processing according to the present embodiment is used as a back grind sheet, a dicing sheet, an expand sheet, a pickup sheet, and the like. Here, as an example of a workpiece|work, glass members, such as semiconductor members, such as a semiconductor wafer and a semiconductor package, and a glass plate, are mentioned.

As mentioned above, the sheet|seat 1 for work processing which concerns on this embodiment can suppress favorably generation|occurrence|production of a cutting piece, especially a thread-like cutting piece, when used for dicing using the rotating round blade. Therefore, it is suitable to use the sheet|seat 1 for a work process which concerns on this embodiment as a dicing sheet especially among the sheet|seat for a work process mentioned above.

Moreover, as mentioned above, the sheet|seat 1 for work processing which concerns on this embodiment has the outstanding antistatic property. The sheet|seat 1 for a work process which concerns on this embodiment can suppress the peeling electrification at the time of isolate|separating a peeling sheet and at the time of isolate|separating a workpiece|work. Further, in the sheet 1 for work processing according to the present embodiment, in a state in which the sheet for work processing is fixed to the spinner table, after cleaning and drying the chips, peeling electrification is also performed when the sheet for work processing is removed from the spinner table. can be effectively suppressed. Therefore, the sheet|seat 1 for work processing which concerns on this embodiment can be used suitably also for such washing|cleaning and drying.

Moreover, when the sheet|seat 1 for a work process which concerns on this embodiment is equipped with the adhesive bond layer mentioned above, the said sheet|seat 1 for a work process can be used as a dicing die-bonding sheet|seat. In addition, when the sheet|seat 1 for work processing which concerns on this embodiment is equipped with the above-mentioned protective film forming layer, the said sheet|seat 1 for work processing can be used as a sheet|seat for dicing and formation of a protective film.

Moreover, when the adhesive layer 12 in the sheet|seat 1 for work processing which concerns on this embodiment is comprised with the above-mentioned active energy ray-curable adhesive, at the time of use, irradiating an active energy ray as follows is also desirable. That is, when the processing of the workpiece is completed on the sheet 1 for processing the workpiece and the workpiece after processing is separated from the sheet 1 for processing the workpiece, it is preferable to irradiate an active energy ray to the pressure-sensitive adhesive layer 12 before the separation. do. Thereby, the adhesive layer 12 hardens, the adhesive force of the adhesive sheet with respect to the workpiece|work after a process falls favorably, and separation|separation of the workpiece|work after a process becomes easy.

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

For example, between the base material 11 and the pressure-sensitive adhesive layer 12 in the sheet 1 for work processing according to the present embodiment, or on the surface on the opposite side to the pressure-sensitive adhesive layer 12 in the base material 11, Another layer may be laminated|stacked. Further, in the surface of the surface layer 111 on the opposite side to the intermediate layer 112 , between the surface layer 111 and the intermediate layer 112 , between the intermediate layer 112 and the back surface layer 113 , and in the back surface layer 113 , Different layers may be laminated on the surface opposite to the intermediate layer 112 of .

(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 base material

28 parts by mass of random polypropylene resin (manufactured by Nippon Polypro, product name "Novatech FX3B"), 42 parts by mass of olefinic elastomer (manufactured by Japan Polypro, product name "Wellnex RFX4V"), and a high molecular weight antistatic agent (Sanyo Kasei) After drying 30 parts by mass (manufactured by the company, product name "Pelectron PVL"), respectively, the pellets for the surface layer and the back surface layer were obtained by kneading with a twin-screw kneader.

Further, 30 parts by mass of a random polypropylene resin (manufactured by Nippon Polypro, product name "Novatech FX3B"), 45 parts by mass of an olefinic elastomer (manufactured by Nippon Polypro, product name "Wellnex RFX4V"), and styrene- as a styrenic elastomer 25 parts by mass of an ethylene-butylene-styrene copolymer (SEBS) (manufactured by Asahi Kasei Corporation, product name "Toughtech H1041", styrene ratio: 30 mass %) was dried, respectively, and then kneaded with a twin-screw kneader to prepare pellets for an intermediate layer. got it

Using the two kinds of pellets obtained as described above, co-extrusion molding was carried out with a small T-die extruder (manufactured by Toyo Seiki Seisakusho, product name "Laboplastomil"), and a surface layer having a thickness of 4 µm and a thickness of 72 µm were used. A base material having a three-layer structure in which an intermediate layer and a back layer having a thickness of 4 μm are sequentially laminated was obtained.

(2) Preparation of adhesive composition

60 mass parts of n-butyl acrylate, 10 mass parts of methyl methacrylate, and 30 mass parts of acrylic acid 2-hydroxyethyl were superposed|polymerized by the solution polymerization method, and the (meth)acrylic acid ester polymer was obtained. Then, while adding 2-methacryloyloxyethyl isocyanate (MOI) in an amount equivalent to 80 mol% with respect to 2-hydroxyethyl acrylate constituting the (meth)acrylic acid ester polymer, a tin-containing catalyst Dibutyltin dilaurate (DBTDL) was added in an amount of 0.13 parts by mass with respect to 100 parts by mass of the (meth)acrylic acid ester polymer. Then, the (meth)acrylic acid ester polymer in which the active energy ray-curable group was introduce|transduced into the side chain was obtained by making it react at 50 degreeC for 24 hours. It was 500,000 when the weight average molecular weight of the said active energy ray-curable polymer was measured by the method mentioned later.

100 parts by mass of the (meth)acrylic acid ester polymer in which an active energy ray-curable group was introduced into the side chain obtained above (in terms of solid content, the same applies hereinafter), and 2-hydroxy-1-a4-[4-(2-) as a photoinitiator 2 parts by mass of hydroxy-2-methylpropionyl)-benzyl]phenyl｝-2-methyl-propan-1-one (manufactured by BASF, product name "Omnirad 127"), and trimethylolpropane-modified tolylene diisocyanate ( The Tosoh Corporation make, product name "colonate L") 1 mass part) was mixed in the solvent, and the coating liquid of the adhesive composition was obtained.

(3) Formation of the pressure-sensitive adhesive layer

With respect to the release surface of a release sheet (manufactured by Lintec, product name "SP-PET381031") comprising a silicone-based release agent layer formed on one side of a polyethylene terephthalate film having a thickness of 38 µm, a coating solution of the adhesive composition obtained in the above step (2) was applied and dried by heating to obtain a laminate in which an adhesive layer having a thickness of 5 µm was formed on the release sheet.

(4) Preparation of adhesive sheet

The sheet for work processing was obtained by corona-treating the surface by the side of the surface layer in the base material obtained in the said process (1), and bonding the surface by the side of the adhesive layer in the laminated body obtained in the said process (3).

Here, the above-mentioned weight average molecular weight (Mw) is a weight average molecular weight in terms of standard polystyrene measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement).

<Measurement conditions>

・Measuring device: Tosoh Corporation, HLC-8320

・GPC column (passed in the following order): manufactured by Tosoh Corporation

TSK gel superH-H

TSK gel superHM-H

TSK gel superH2000

・Measurement solvent: tetrahydrofuran

・Measurement temperature: 40℃

[Examples 2-3, Comparative Examples 1-3]

A sheet for work processing was manufactured in the same manner as in Example 1 except that the composition of the pellets for forming each layer of the substrate and the thickness of each layer were changed as described in Table 1. Moreover, in Examples 2 and 3, the maleic anhydride adduct of the ethylene-ethyl acrylate copolymer as an acid-modified resin in the surface layer (SK Functional Polymer company make, product name "BONDINE LX4110", ethyl acrylate content: 5 mass %, Acidic content: 3 mass %) was mix|blended 15 mass parts.

In Comparative Example 1, a styrene-ethylene/ethylene/propylene-styrene block copolymer (SEEPS) (“Heibler 7311F” manufactured by Kuraray Corporation, a styrene ratio: 12% by mass) was used as the styrene-based elastomer. In Comparative Examples 2 and 3, ethylene-butylene-styrene copolymer (SEBS) (manufactured by Asahi Chemical Co., Ltd., product name "Toughtech H1062", styrene ratio: 18 mass %) was used as a styrene-type elastomer.

[Comparative Example 4]

Using the apparatus similar to Example 1, the film which consists of a single-layered ethylene-methacrylic acid copolymer (The Mitsui Dow Polychemical company make, product name "Nucrel N0903HC") was produced. What irradiated the 10 kGy electron beam once for 2.2 seconds to the surface by the side of the adhesive layer lamination|stacking in the obtained film was used as a base material. Using this base material, it carried out similarly to Example 1, and manufactured the sheet|seat for work processing.

[Comparative Example 5]

Using the apparatus similar to Example 1, the film which consists of a single-layered ethylene-methacrylic acid copolymer (The Mitsui Dow Polychemical company make, product name "Nucrel N0903HC") was produced. What irradiated the 10 kGy electron beam twice every 2.2 second to the surface by the side of the adhesive layer lamination|stacking in the obtained film was used as the base material. Using this base material, it carried out similarly to Example 1, and manufactured the sheet|seat for work processing.

[Test Example 1] (Viscoelasticity measurement)

The base material (80 micrometers in thickness) manufactured in the Example and the comparative example was cut out to 20 mm long side (distance between chuck|zippers), and short side 4 mm, and this was used as the sample. At this time, it was made so that the MD direction of a base material might become a long side direction.

Using dynamic viscoelasticity measurement (manufactured by A&D Corporation, product name “Leo Vibron (registered trademark) DDV-01FP”), the sample was subjected to viscoelasticity measurement under the following measurement conditions to determine the loss elastic modulus and storage modulus. acquired

From the obtained measured values, the loss tangent tanδ (loss modulus/storage modulus) at 90°C, 110°C and 120°C was obtained (represented by tanδ(90), tanδ(100), tanδ(110), and tanδ(120), respectively). ). Further, tan δ (110)/tan δ (90) and tan δ (120)/tan δ (110) were calculated from these results. A result is shown in Table 2.

<Measurement conditions>

Measurement temperature range: -30℃ to 120℃

Temperature increase rate: 1°C/min

Measuring Mode: Tensile

Frequency: 11Hz

[Test Example 2] (Measurement of surface resistivity)

After the substrates prepared in Examples and Comparative Examples were subjected to humidity control at 23° C. and 50% relative humidity for 24 hours, the surface resistivity of the surface on the surface layer side was measured using DIGITAL ELECTROMETER (manufactured by ADVANTEST) at an applied voltage of 100 V was measured with A result is shown in Table 2.

Moreover, the sheet|seat for work processing manufactured by the Example and the comparative example was cut out to 100 mm x 100 mm, and this was made into the sample for surface resistivity measurement. About the adhesive layer in the said sample for surface resistivity measurement, ultraviolet-ray (UV) was irradiated using the ultraviolet irradiation apparatus (The Lintech company make, product name "RAD-2000") through a base material (illuminance: 230 mW/cm<2>, Light quantity: 190 mJ/cm<2>), the adhesive layer was hardened. After the sample for measuring the surface resistivity after UV irradiation was subjected to humidity control at 23° C. and 50% relative humidity for 24 hours, the release sheet was peeled off, and the surface resistivity of the exposed pressure-sensitive adhesive layer side (adhesive surface) was measured in the same manner as above. This result is also shown in Table 2.

[Test Example 3] (Evaluation of antistatic properties)

Using a grinder (manufactured by Disco Corporation, product name "DFG8540"), the single side|surface of the 6-inch silicon wafer was ground until thickness became 350 micrometers. The exposed surface of the adhesive layer exposed by peeling a peeling sheet from the sheet|seat for work processing manufactured by the Example and the comparative example using the laminator about the said grinding surface was affixed.

After 20 minutes from sticking, using a dicing apparatus (manufactured by Disco Corporation, product name "DFD6362"), the silicon wafer was diced under the following dicing conditions to separate the silicon wafer into chips.

Dicing conditions

Chip size: 10mm x 10mm

Cutting height: 60㎛

Blade: Product name "ZH05-SD2000-Z1-90 CC"

Blade rotation speed: 35000rpm

Cutting speed: 60mm/sec

Cutting amount: 1.0L/min

Cutting water temperature: 20℃

After dicing, the chips obtained as described above were washed and dried while the sheet for work processing was fixed by adsorption on the spinner table. And the electrification voltage (V) of the sheet|seat for a workpiece|work processing in immediately after lifting the sheet|seat for a workpiece|work processing from the spinner table was measured using the measuring instrument (The product made by Prostat, product name "PFK-100"). And antistatic property was evaluated based on the following criteria. Table 2 shows the charging voltage and evaluation results.

(circle): The charging voltage was 300V or less.

x: The charging voltage was more than 300V.

[Test Example 4] (Evaluation of the effect of inhibiting cutting pieces)

After peeling the release sheet from the work processing sheet produced in Examples and Comparative Examples, using a tape mounter (manufactured by Lintec, product name "RAD2500m/12"), the exposed surface of the exposed pressure-sensitive adhesive layer was placed on a 6-inch silicon wafer affixed on one side of the Then, the ring frame for dicing was attached to the periphery (position which does not overlap with a silicon wafer) of the said exposed surface in the sheet|seat for a workpiece|work processing. Further, the sheet for work processing was cut according to the outer diameter of the ring frame.

Thereafter, using a dicing apparatus (manufactured by Disco, product name "DFD6362"), the silicon wafer was divided into chips having a size of 0.8 mm x 20 mm by performing dicing under the following dicing conditions.

Dicing conditions

Wafer thickness: 100㎛

Blade: Both Z1 and Z2 below are made by Disco

Z1: Product name 「ZH05-SD3500-N1-50 DF01」

Z2: Product name "ZH05-SD3000-N1-50ED"

number of blade rotations

Z1: 50000rpm

Z2: 35000rpm

Cutting speed: 100mm/sec

blade height

Z1: 0.135mm

Z2: 0.055 mm

Cutting amount: 1.0L/min

Cutting water temperature: 20℃

After dicing, the surface of 1000 obtained chips was observed using the visual inspection apparatus (made by Camtek, product name "Eagle"), and the number of cutting pieces was measured. Then, the number of cutting pieces per chip (= cutting piece occurrence frequency) was calculated. A result is shown in Table 2.

And the cutting-fragment suppression effect was evaluated based on the following criteria. An evaluation result is shown in Table 2.

(circle): The frequency of occurrence of cutting pieces was less than 0.002.

x: The frequency of occurrence of chips was 0.002 or more.

[Table 1]

[Table 2]

As is clear from Table 2, the sheet for work processing produced in the Examples satisfactorily suppressed the generation of chips while exhibiting excellent antistatic properties.

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

1: Sheet for work processing
11: Write
111: surface layer
112: middle layer
113: back layer
12: adhesive layer

Claims (9)

A sheet for work processing comprising a substrate and an adhesive layer laminated on one side of the substrate, the sheet comprising:
The substrate includes a surface layer located proximal to the pressure-sensitive adhesive layer, a back surface layer located distal to the pressure-sensitive adhesive layer, and an intermediate layer located between the surface layer and the back surface layer do,
At least the back layer contains an antistatic agent,
The intermediate layer contains a styrenic thermoplastic elastomer,
When the loss tangent at 90° C. measured in viscoelasticity at a frequency of 11 Hz with respect to the substrate is tanδ(90), the loss tangent at 110°C is tanδ(110), and the loss tangent at 120°C is tanδ(120),
tanδ(110) is 0.25 or more in absolute value,
tanδ(110)/tanδ(90) is 1.3 or more,
A sheet for work processing, characterized in that tanδ(120)/tanδ(110) is 0.9 or less. According to claim 1,
The said surface layer contains the antistatic agent, The sheet|seat for work processing characterized by the above-mentioned. According to claim 1,
The sheet for work processing, wherein the surface layer contains a polyolefin-based resin and an olefin-based thermoplastic elastomer. According to claim 1,
The sheet for work processing, wherein the back layer contains an olefinic thermoplastic elastomer. According to claim 1,
The intermediate layer contains a styrene-based thermoplastic elastomer, a polyolefin-based resin and an olefin-based thermoplastic elastomer. According to claim 1,
The intermediate layer does not contain an antistatic agent, or
The sheet for work processing, wherein the intermediate layer contains an antistatic agent in a content (unit: mass %) smaller than each of the surface layer and the back layer. According to claim 1,
The said antistatic agent is a polymer type antistatic agent, The sheet|seat for work processing characterized by the above-mentioned. According to claim 1,
The surface resistivity of the surface on the opposite side to the base material in the said adhesive layer is 1.0x10 ¹³ ohm/square or less, The sheet|seat for work processing characterized by the above-mentioned. 9. The method according to any one of claims 1 to 8,
A sheet for work processing, characterized in that it is a dicing sheet.

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