WO2019111760A1 - Workpiece machining sheet and production method for machined workpiece - Google Patents

Abstract

A workpiece machining sheet comprising a base material and an adhesive layer laminated on one surface side of the base material. The oxygen atom ratio as measured by X ray photoelectron spectroscopy at a position in the adhesive layer that is at a depth of 100 nm from a surface on the opposite side of the adhesive layer to the base material is 20–29 atom%. Said workpiece machining sheet can: suppress water incursion into the boundary between the workpiece machining sheet and an object to be cut and the boundary between the workpiece machining sheet and an obtained chip; and adequately remove adhesive from the object to be cut, by using running water, said adhesive being derived from the adhesive layer and being attached to the object to be cut when the machining the object to be cut such as a semiconductor wafer, etc.

Description

Sheet for work processing and manufacturing method of processed work

The present invention relates to a work processing sheet that can be suitably used for dicing, and a method of manufacturing a processed work using the work processing sheet.

Semiconductor wafers such as silicon and gallium arsenide and various packages (hereinafter, these may be collectively referred to as "objects to be cut") are manufactured in a large diameter state, and these are element chips (hereinafter, "elements" After being cut (diced) into chips and separated (picked up) individually, they are transferred to the next step, the mounting step. At this time, a workpiece such as a semiconductor wafer is subjected to dicing, cleaning, drying, expanding, pickup and mounting steps in a state of being attached to a work processing sheet provided with a base material and an adhesive layer. Ru.

In the above-described dicing process, the dicing blade, the workpiece and the work processing sheet are heated by the frictional heat generated between the rotating dicing blade and the workpiece or the work processing sheet. In addition, in the dicing process, a cut piece may be generated from a workpiece or a sheet for processing a work, which may adhere to the workpiece.

Therefore, when performing a dicing process, while supplying flowing water with respect to a cutting part normally, while cooling a dicing blade etc., removing the produced | generated cutting piece from a to-be-cut object is performed.

Patent Document 1 discloses that the contact angle to pure water of the surface of the pressure-sensitive adhesive layer on the side opposite to the base material before ultraviolet irradiation is 82 ° to 114 ° for the purpose of promoting the removal of the cutting pieces by the flowing water. There is disclosed a work processing sheet having a contact angle of 44 ° to 64 ° to methylene iodide and a peak value of probe tack test of 294 to 578 kPa in the pressure-sensitive adhesive layer before ultraviolet irradiation. .

Patent No. 5019657

However, when performing the dicing step using the conventional work processing sheet as disclosed in Patent Document 1, the adhesive derived from the adhesive layer of the work processing sheet is sufficiently removed from the object to be cut I could not.

In addition, generally, water may infiltrate into the interface between the work processing sheet and the workpiece or the interface between the work processing sheet and the obtained chip due to the supply of flowing water at the time of dicing. . Such ingress of water may cause chipping or chipping.

The present invention has been made in view of such a situation, and it is possible to suppress the infiltration of water at the interface between the work processing sheet and the workpiece or at the interface between the work processing sheet and the obtained chip. A work processing sheet capable of favorably removing the adhesive derived from the pressure-sensitive adhesive layer attached to the object to be cut during processing of the object to be cut such as a semiconductor wafer from the object to be cut with flowing water; An object of the present invention is to provide a method of manufacturing a processed work using the work processing sheet.

In order to achieve the above object, firstly, the present invention is a sheet for processing a work comprising a substrate and a pressure-sensitive adhesive layer laminated on one side of the substrate, and a position in the pressure-sensitive adhesive layer Among them, the oxygen atom ratio measured by X-ray photoelectron spectroscopy analysis at a position 100 nm deep from the surface opposite to the substrate in the pressure-sensitive adhesive layer is 20 atomic% or more and 29 atomic% or less A sheet for processing a work characterized by the present invention is provided (Invention 1).

In the work processing sheet according to the above invention (Invention 1), the oxygen atom ratio at the position of 100 nm in depth from the surface on the side opposite to the substrate (hereinafter sometimes referred to as "adhesive surface") in the adhesive layer is the above Within the range, the pressure-sensitive adhesive in the pressure-sensitive adhesive layer has a predetermined affinity for water, whereby the penetration of water at the interface between the pressure-sensitive adhesive surface and the object to be cut or the obtained chip is obtained. It is possible to remove the adhesive adhering to the object to be cut well by flowing water while suppressing the pressure.

In the said invention (invention 1), it is preferable that the thickness of the said adhesive layer is 1.5 micrometers or more and less than 50 micrometers (invention 2).

In the said invention (invention 1 and 2), it is preferable that the water contact angle of the surface on the opposite side to the said base material in the said adhesive layer is 50 degrees or more and 80 degrees or less (invention 3).

In the above inventions (Inventions 1 to 3), the adhesion of the work processing sheet to the silicon wafer is F1, and the work processing sheet is immersed in distilled water at 23 ° C. for 12 hours and further dried at 23 ° C. for 24 hours Assuming that the adhesive force of the work processing sheet to the silicon wafer later is F2, the following formula (1)
Decreasing rate of adhesion (%) = {(F1-F2) / F1} × 100 (1)
It is preferable that the reduction rate of the adhesive force calculated from the above is 20% or more and 50% or less (Invention 4).

In the said invention (invention 4), it is preferable that the said adhesive force F1 is 1000 mN / 25 mm or more and 10000 mN / 25 mm or less (invention 5).

In the said invention (invention 4 and 5), it is preferable that the said adhesive force F2 is 900 mN / 25 mm or more and 8000 mN / 25 mm or less (invention 6).

In the above inventions (Inventions 1-6), the pressure-sensitive adhesive layer is preferably composed of an active energy ray-curable adhesive (Invention 7).

In the above invention (Invention 7), the active energy ray-curable adhesive comprises, as monomer units constituting a polymer, methyl acrylate, 2-methoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate and The pressure-sensitive adhesive is preferably formed from a pressure-sensitive adhesive composition containing an acrylic copolymer containing at least one selected from methoxyethylene glycol (meth) acrylate (Invention 8).

In the above inventions (Inventions 1 to 8), a dicing sheet is preferable (Invention 9).

Secondly, the present invention provides a bonding step of bonding a work with the surface of the pressure-sensitive adhesive layer opposite to the substrate in the work processing sheet (inventions 1 to 9), the work processing A processing step of obtaining a processed work laminated on the work processing sheet by processing the work on a sheet, and irradiating the pressure-sensitive adhesive layer with an active energy ray, the pressure-sensitive adhesive layer And a separation step of separating the processed work from the work processing sheet after irradiation with an active energy ray, and curing the work processing sheet to lower the adhesion of the work processing sheet to the processed work. The present invention provides a method of producing a processed work characterized by the present invention (Invention 10).

The sheet for processing a work according to the present invention cuts a semiconductor wafer or the like while suppressing the infiltration of water at the interface between the sheet for processing the work and the workpiece or at the interface between the sheet for processing the work and the obtained chip. The pressure-sensitive adhesive derived from the pressure-sensitive adhesive layer attached to the object to be cut during processing of the object can be favorably removed from the object to be cut by flowing water. Moreover, according to the method of manufacturing a processed work according to the present invention, it is possible to efficiently manufacture the processed work.

Hereinafter, embodiments of the present invention will be described.
[Workpiece processing sheet]
The work processing sheet according to the present embodiment includes a base, and a pressure-sensitive adhesive layer laminated on one side of the base.

1. Physical Properties of Sheet for Processing of Workpiece In the sheet for work processing according to the present embodiment, X-ray photoelectron spectroscopy analysis at a position 100 nm deep from the surface of the pressure-sensitive adhesive layer opposite to the substrate in the position within the pressure-sensitive adhesive layer The oxygen atom ratio measured by the above is 20 atomic% or more and 29 atomic% or less. As a result, the pressure-sensitive adhesive in the pressure-sensitive adhesive layer has a predetermined affinity for water. In addition, the detail of the measuring method of the said oxygen atom ratio is as having described in the test example mentioned later.

Generally, in the case of dicing using a dicing blade, a rotating dicing blade is applied to an object to be cut while supplying flowing water to the cutting portion to cut the object to be cut. At this time, the rotating dicing blade may contact not only the workpiece but also the pressure-sensitive adhesive layer. In such a contact portion, cutting of the pressure-sensitive adhesive layer or rolling up of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer by a dicing blade occurs, and as a result, a small piece of the pressure-sensitive adhesive is formed. The small pieces adhere to an object to be cut and a formed chip, which adversely affects the handling of the chip thereafter, and causes deterioration of the quality of the chip and the product on which the chip is mounted. Here, since the small pieces of the pressure-sensitive adhesive are formed as described above, most of the small pieces are present inside the pressure-sensitive adhesive layer when the pressure-sensitive adhesive layer is formed.

In the work processing sheet according to the present embodiment, as described above, since the pressure-sensitive adhesive in the pressure-sensitive adhesive layer has a predetermined affinity for water, small pieces of the pressure-sensitive adhesive are cut objects Even when it is attached to a chip, the surface of the small piece has a predetermined affinity to water. Therefore, according to the work processing sheet according to the present embodiment, the entry of water at the interface between the adhesive surface and the object to be cut or the obtained chip due to the flowing water supplied at the time of dicing is suppressed. The flowing water can well remove the adhesive adhering to the material to be cut and chips from the material to be cut.

On the other hand, in the conventional work processing sheet, the oxygen atom ratio in the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer tends to be large, and accordingly, the oxygen atom ratio in the pressure-sensitive adhesive layer tends to be small. This is usually the surface (surface in contact with air) of the coating film formed by applying the coating solution under the influence of moisture present in the air when forming the pressure-sensitive adhesive layer using the coating solution of the pressure-sensitive adhesive composition. It is considered that one of the causes is that the component having an oxygen atom tends to be localized. In the conventional work processing sheet, the inside of the pressure-sensitive adhesive layer does not have sufficient affinity to water because the oxygen atom ratio inside the pressure-sensitive adhesive layer is not sufficiently large. Therefore, even if using flowing water, a small piece of adhesive produced from a conventional work processing sheet can not be removed well from a workpiece or a chip to which it adheres.

The pressure-sensitive adhesive in the pressure-sensitive adhesive layer does not have sufficient affinity for water when the oxygen atom ratio described above is less than 20 atomic%, and the small pieces of the pressure-sensitive adhesive are removed from the cut object or chip It can not be done. Further, when the oxygen atom ratio described above exceeds 29 atomic%, the affinity to water in the entire pressure-sensitive adhesive layer is excessively increased, and water at the interface between the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer and the object to be cut or the obtained chip Infiltration occurs.

From the viewpoint of better removing the adhesive attached to the object to be cut and the obtained chip by flowing water and at the same time better suppressing the entry of water at the interface between the adhesive surface and the object to be cut and the chip, the present embodiment In the work processing sheet, the oxygen atom ratio described above is preferably 21 atomic% or more. Moreover, it is preferable that the oxygen atom ratio mentioned above is 28 atomic% or less.

Although the work processing sheet according to the present embodiment defines that the oxygen atom ratio at a position 100 nm deep from the adhesive surface is 20 atomic% or more and 29 atomic% or less, such a specification According to the above, it is presumed that the pressure-sensitive adhesive layer has a predetermined affinity for water not only at a position 100 nm deep from the pressure-sensitive adhesive surface but also for the entire inside of the pressure-sensitive adhesive layer (except for the vicinity of the adhesive surface). can do. Therefore, when the work processing sheet according to the present embodiment is used for dicing, the effect of removing the adhesive by flowing water and the penetration of water described above regardless of the depth of the rotating dicing blade entering the adhesive layer Can be obtained well.

In the work processing sheet according to the present embodiment, the oxygen atom ratio measured by X-ray photoelectron spectroscopy on the surface (adhesive surface) opposite to the substrate in the pressure-sensitive adhesive layer is 29 atomic% or less Is more preferable, and 28 atomic% or less is more preferable. When the oxygen atom ratio in the adhesive surface is 29 atomic% or less, the affinity for water in the adhesive surface is relatively low. This makes it possible to effectively suppress the entry of water at the interface between the adhesive surface and the object to be cut or the obtained chip. Moreover, in the work processing sheet according to the present embodiment, the oxygen atom ratio measured by X-ray photoelectron spectroscopy on the adhesive surface is preferably 20 atomic% or more, and particularly preferably 25 atomic% or more. Since the oxygen atom ratio in the adhesive surface is 20 atomic% or more, the oxygen atom ratio at a position 100 nm deep from the adhesive surface can be easily adjusted to the above-mentioned range, and the adhesive attached to the object to be cut or chip is Makes it easy to remove. In addition, the detail of the measuring method of the oxygen atom ratio in the adhesive surface is as having described in the test example mentioned later.

In the work processing sheet according to the present embodiment, the water contact angle of the surface on the opposite side to the base material in the pressure-sensitive adhesive layer is preferably 50 ° or more, particularly preferably 55 ° or more, and further preferably It is preferable that it is 60 degrees or more. The water contact angle is preferably 80 ° or less, particularly preferably 75 ° or less, and further preferably 70 ° or less. When the water contact angle is 50 ° or more, the affinity of the pressure-sensitive adhesive surface to water becomes appropriate, and the penetration of water at the interface between the pressure-sensitive adhesive surface and the object to be cut or the obtained chip is more effectively performed. It becomes possible to suppress. In addition, when the water contact angle is 80 ° or less, the oxygen atom ratio at a position 100 nm deep from the adhesive surface can be easily adjusted to the above-mentioned range, and the adhesive attached to the object to be cut or the chip is It becomes easy to remove. In addition, in this specification, a water contact angle means what was measured before an active energy ray is irradiated with respect to the sheet | seat for workpiece processing. Moreover, the detail of the measuring method of the water contact angle mentioned above is as described in the test example mentioned later.

In the work processing sheet according to the present embodiment, the adhesion of the work processing sheet to the silicon wafer is F1, and the work processing sheet is immersed in distilled water at 23 ° C. for 12 hours and further dried at 23 ° C. for 24 hours Assuming that the adhesion of the work processing sheet to the silicon wafer is F2, the following formula (1)
Decreasing rate of adhesion (%) = {(F1-F2) / F1} × 100 (1)
It is preferable that the decreasing rate of the adhesive force calculated from the above is 20% or more. Moreover, it is preferable that the reduction rate of the said adhesive force is 50% or less. When the adhesive strength reduction rate is 20% or more, even if the adhesive adheres to the object to be cut, the adhesive strength of the adhesive is appropriately decreased by the flowing water, and the adhesive is favorably used. Can be removed. Further, by the above-mentioned adhesive strength reduction rate being 50% or less, the adhesive strength of the pressure-sensitive adhesive layer to the cut object is appropriately maintained even after the pressure-sensitive adhesive layer is exposed to running water. The cut products and chips obtained can be well retained on the pressure-sensitive adhesive layer. In the present specification, each of the adhesive force F1 and the adhesive force F2 is an adhesive force measured before the work processing sheet is irradiated with an active energy ray. Moreover, the details of the measuring method of the adhesive force F1 and the adhesive force F2 are as described in the test example mentioned later.

In the work processing sheet according to the present embodiment, the above-mentioned adhesive force F1 is preferably 1000 mN / 25 mm or more, particularly preferably 2000 mN / 25 mm or more, and further preferably 3000 mN / 25 mm or more . Further, the adhesive force F1 is preferably 10000 mN / 25 mm or less, and particularly preferably 7000 mN / 25 mm or less.

Further, in the work processing sheet according to the present embodiment, the above-mentioned adhesive force F2 is preferably 900 mN / 25 mm or more, particularly preferably 1500 mN / 25 mm or more, and further preferably 2000 mN / 25 mm or more. Is preferred. Further, the adhesive force F2 is preferably 8000 mN / 25 mm or less, and particularly preferably 5000 mN / 25 mm or less.

When the adhesive force F1 and the adhesive force F2 are in the above ranges, it is easy to adjust the reduction rate of the adhesive force to the above-described range.

2. Constituent member of work processing sheet (1) base material In the work processing sheet according to the present embodiment, the base material exerts a desired function in the process of using the work processing sheet, and preferably, the adhesive layer is cured There is no particular limitation as long as it exhibits good permeability to the active energy ray irradiated.

For example, the substrate is preferably a resin film mainly composed of a resin material, and as a specific example thereof, an ethylene-vinyl acetate copolymer film; an ethylene- (meth) acrylic acid copolymer film, Ethylene-based copolymer films such as ethylene- (meth) acrylate copolymer film and other ethylene- (meth) acrylate copolymer films; polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene Films, ethylene-norbornene copolymer films, polyolefin films such as norbornene resin film; polyvinyl chloride films such as polyvinyl chloride film, vinyl chloride copolymer film; polyethylene terephthalate film, polybutylene tere (Meth) acrylic acid ester copolymer film; polyurethane film; polyimide film; polystyrene films; polycarbonate films; tallate film, polyester films such as polyethylene naphthalate and a fluorine resin film. Examples of polyethylene films include low density polyethylene (LDPE) films, linear low density polyethylene (LLDPE) films, high density polyethylene (HDPE) films, and the like. In addition, modified films such as these crosslinked films and ionomer films are also used. Moreover, the base material may be a laminated film in which a plurality of the films described above are laminated. In this laminated film, the materials constituting each layer may be the same or different. Among the above-mentioned films, it is preferable to use an ethylene-methyl methacrylate copolymer film as the substrate from the viewpoint of excellent flexibility. In addition, "(meth) acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same applies to other similar terms.

The substrate may contain various additives such as a flame retardant, a plasticizer, an antistatic agent, a lubricant, an antioxidant, a colorant, an infrared absorber, an ultraviolet absorber, an ion scavenger and the like. The content of these additives is not particularly limited, but it is preferable to set the range in which the substrate exhibits a desired function.

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

Although the thickness of the substrate can be appropriately set depending on the method in which the work processing sheet is used, in general, the thickness is preferably 20 μm or more, and particularly preferably 25 μm or more. The thickness is usually preferably 450 μm or less, particularly preferably 300 μm or less.

(2) Pressure-sensitive adhesive layer In the work-processing sheet according to the present embodiment, the pressure-sensitive adhesive layer exerts a desired adhesive force on the object to be cut, and the oxygen mentioned above at a depth of 100 nm from the adhesive surface It is not particularly limited as long as the atomic ratio can be achieved.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be an active energy ray-curable pressure-sensitive adhesive or an active energy ray non-curable pressure-sensitive adhesive, but is preferably an active energy ray-curable pressure-sensitive adhesive . The pressure-sensitive adhesive layer is made of an active energy ray-curable pressure-sensitive adhesive, whereby when the object to be cut attached to the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer is separated from the adhesive surface, adhesion is performed by active energy ray irradiation. The agent layer can be cured to reduce the adhesion of the work processing sheet to the workpiece. This facilitates separation of the adhesive surface of the adhesive layer and the object to be cut.

The active energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be a polymer having an active energy ray-curable property as a main component, or an active energy ray non-curable polymer (active energy ray-curable It may be based on a mixture of a polymer (not having a polymer) and a monomer and / or an oligomer having at least one active energy ray-curable group. In addition, it may be a mixture of a polymer having active energy ray curability and a non-active energy ray curable polymer. It may also be a mixture of a polymer having active energy ray curability and a monomer and / or oligomer having at least one or more active energy ray curable groups. Furthermore, it may be a mixture of a polymer having active energy ray curability, an active energy ray non-curable polymer, and a monomer and / or oligomer having at least one or more active energy ray curable groups.

First, the case where the active energy ray-curable adhesive is based on a polymer having an active energy ray-curable property will be described below.

A polymer having active energy ray curability has a (meth) acrylic acid ester (co) polymer (A) (hereinafter referred to as) having a functional group (active energy ray curable group) having active energy ray curability in the side chain. It is preferable that it is "an active energy ray curable polymer (A)." The active energy ray-curable polymer (A) comprises an acrylic copolymer (a1) having a functional group-containing monomer unit and an unsaturated group-containing compound (a2) having a functional group to be bonded to the functional group. It is preferable that it is obtained by making it react.

The acrylic copolymer (a1) may be referred to as a monomer for adjusting the hydrophilicity of the acrylic copolymer (a1) as a monomer unit constituting the polymer (hereinafter referred to as a "hydrophilic adjusting monomer". Is preferably selected, and in particular, as a specific example thereof, selected from methyl acrylate, 2-methoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate and methoxy ethylene glycol (meth) acrylate It is preferable to include at least one.

By using the above-mentioned hydrophilicity-adjusting monomer, it becomes easy to adjust the oxygen atom ratio at the position 100 nm deep from the adhesive surface to the above-mentioned range. There are two possible reasons for this. However, the reason is not limited to these two, and these two may not be the case.

The first reason is that many of the above-mentioned hydrophilicity-adjusting monomers have a relatively large number of oxygen atoms, and by using an acrylic copolymer (a1) composed of the monomers, adhesion The absolute amount of oxygen atoms in the agent layer also increases, and the oxygen atom ratio at a position 100 nm deep from the adhesive surface can be easily adjusted to the above-mentioned range.

The second reason is that by using the above-mentioned hydrophilicity-adjusting monomer, the uneven distribution of oxygen atoms in the pressure-sensitive adhesive layer is controlled, whereby the oxygen atom ratio at a position 100 nm deep from the pressure-sensitive adhesive surface is It becomes easy to adjust to the range. Generally, when a pressure-sensitive adhesive layer is formed using a coating solution of a pressure-sensitive adhesive composition, the surface (surface in contact with air) of a coating film formed by applying the coating solution is affected by the influence of moisture present in the air. Tends to be unevenly distributed in the component having an oxygen atom. For example, when the acrylic copolymer (a1) contains 2-hydroxyethyl acrylate, which will be described later, as a constituent monomer, the part derived from the monomer tends to be unevenly distributed on the surface. However, when the acrylic copolymer (a1) contains the above-mentioned hydrophilicity-adjusting monomer, a component having an oxygen atom (such as 2-hydroxyethyl acrylate or a hydrophilicity-adjusting monomer) is uniformly present in the coating film. As a result, the oxygen atom ratio at a position 100 nm deep from the adhesive surface can be easily adjusted to the above-mentioned range.

From the viewpoint of easily adjusting the oxygen atom ratio at the position of 100 nm in depth from the adhesive surface to the above-mentioned range, the acrylic copolymer (a1) is a monomer unit constituting the polymer, which is the above-mentioned hydrophilicity adjusting monomer Among them, it is preferable to contain at least one of methyl acrylate, 2-methoxyethyl acrylate and methoxy ethylene glycol acrylate.

When the acrylic copolymer (a1) contains methyl acrylate as a monomer unit constituting a polymer, the content of methyl acrylate is preferably 10% by mass or more, and particularly preferably 20% by mass or more Is more preferable, and 30% by mass or more is more preferable. Moreover, it is preferable that content of methyl acrylate is 85 mass% or less. With these contents, it becomes easy to adjust the oxygen atom ratio at a position 100 nm deep from the adhesive surface in the above-mentioned range. In addition, in this specification, content (mass%) of the (meth) acrylic-acid alkoxyester mentioned above means content with respect to the all monomers which comprise an acryl-type copolymer (a1). In addition, the content (% by mass) of other monomers described later is also meant to be the content with respect to all the monomers constituting the acrylic copolymer (a1).

When the acrylic copolymer (a1) contains 2-methoxyethyl acrylate as a monomer unit constituting a polymer, the content of 2-methoxyethyl acrylate is preferably 10% by mass or more, In particular, the content is preferably 20% by mass or more, and more preferably 30% by mass or more. Further, the content of 2-methoxyethyl acrylate is preferably 85% by mass or less, particularly preferably 80% by mass or less, and further preferably 70% by mass or less. With these contents, it becomes easy to adjust the oxygen atom ratio at a position 100 nm deep from the adhesive surface in the above-mentioned range.

When the acrylic copolymer (a1) contains both methyl acrylate and 2-methoxyethyl acrylate as monomer units constituting the polymer, the content of methyl acrylate and 2-methoxyethyl acrylate is The total value is preferably 10% by mass or more, particularly preferably 30% by mass or more, and further preferably 50% by mass or more. Moreover, it is preferable that the said sum total is 90 mass% or less, and it is preferable that it is especially 85 mass% or less. It becomes easy to adjust the oxygen atom ratio in the position of 100 nm in depth from the adhesive surface as the said total value is these ranges by the range mentioned above.

Furthermore, when the acrylic copolymer (a1) contains methoxyethylene glycol acrylate as a monomer unit constituting a polymer, the content of methoxyethylene glycol acrylate is preferably 10% by mass or more, and particularly preferably 30. It is preferable that it is mass% or more. Further, the content of methoxyethylene glycol acrylate is preferably 90% by mass or less, and particularly preferably 85% by mass or less. With these contents, it becomes easy to adjust the oxygen atom ratio at a position 100 nm deep from the adhesive surface in the above-mentioned range.

The acrylic copolymer (a1) preferably contains a structural unit derived from a functional group-containing monomer, in addition to the above-mentioned hydrophilicity adjusting monomer.

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

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

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

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

The acrylic copolymer (a1) preferably contains 1% by mass or more, particularly preferably 5% by mass or more, and further preferably 10% by mass or more of the structural unit derived from the functional group-containing monomer. It is preferable to do. The acrylic copolymer (a1) preferably contains 35% by mass or less, and particularly preferably 30% by mass or less, of the constituent unit derived from the functional group-containing monomer.

In addition to the monomers described above, the acrylic copolymer (a1) may be referred to as a structural unit derived from a (meth) acrylic acid ester monomer other than methyl acrylate or a derivative thereof (hereinafter referred to as "optional monomer"). May be included.

As the (meth) acrylic acid ester monomer, in addition to (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group, for example, a monomer having an alicyclic structure in the molecule (alicyclic structure containing) Monomers are preferably used.

As the (meth) acrylic acid alkyl ester, (meth) acrylic acid alkyl ester having, in particular, an alkyl group having 1 to 18 carbon atoms, such as methyl methacrylate, ethyl (meth) acrylate, propyl (meth) acrylate, Among these, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and the like are preferably used, and among them, n-butyl (meth) acrylate is used from the viewpoint of easy adjustment of adhesion properties. Is preferred. One of these may be used alone, or two or more of these may be used in combination.

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

When the acrylic copolymer (a1) contains the above-mentioned optional monomer, the acrylic copolymer (a1) preferably contains 50% by mass or more of the above-mentioned optional monomer, and particularly contains 60% by mass or more It is more preferable to contain 70 mass% or more. The acrylic copolymer (a1) preferably contains the above-mentioned optional monomer at 99% by mass or less, particularly preferably at 95% by mass or less, and further contains 90% by mass or less Is preferred.

The acrylic copolymer (a1) can be obtained preferably by copolymerizing the above-mentioned hydrophilicity-adjusting monomer, a functional group-containing monomer, and optionally, an optional monomer in a conventional manner. Besides, dimethyl acrylamide, vinyl formate, vinyl acetate, styrene and the like may be copolymerized.

An active energy ray-curable polymer (A) can be reacted by reacting the acrylic copolymer (a1) having the functional group-containing monomer unit with the unsaturated group-containing compound (a2) having a functional group to be bonded to the functional group. A) is obtained.

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

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

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

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

The weight average molecular weight (Mw) of the active energy ray curable polymer (A) thus obtained is preferably 10,000 or more, particularly preferably 150,000 or more, and further preferably 200,000 or more. Preferably there. Further, the weight average molecular weight (Mw) is preferably 1.5 million or less, and particularly preferably 1 million or less. In addition, the weight average molecular weight (Mw) in this specification is a value of standard polystyrene conversion measured by the gel permeation chromatography method (GPC method).

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

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

Examples of such active energy ray curable monomers and / or oligomers (B) include monofunctional acrylic acid esters such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, Pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene Multifunctional acrylic acid esters such as glycol di (meth) acrylate and dimethylol tricyclodecane di (meth) acrylate, polyester oligo (meth) acrylate, polyurethane oligo ( Data) acrylate, and the like.

When an active energy ray-curable monomer and / or oligomer (B) is blended with the active energy ray-curable polymer (A), the active energy ray-curable monomer and / or in the active energy ray-curable adhesive Alternatively, the content of the oligomer (B) is preferably more than 0 parts by mass, particularly preferably 60 parts by mass or more, with respect to 100 parts by mass of the active energy ray-curable polymer (A). Further, the content is preferably 250 parts by mass or less, particularly preferably 200 parts by mass or less, with respect to 100 parts by mass of the active energy ray-curable polymer (A).

Here, 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 (C), and use of this photoinitiator (C) Thus, the polymerization curing time and the light irradiation dose can be reduced.

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

The photopolymerization initiator (C) is an active energy ray curable polymer (A) (when the active energy ray curable monomer and / or oligomer (B) is blended, the active energy ray curable polymer (A) And at least 0.1 part by weight, in particular at least 0.5 parts by weight, per 100 parts by weight of the total amount of 100 parts by weight of the monomer and / or oligomer (B). preferable. The photopolymerization initiator (C) is an active energy ray curable polymer (A) (in the case of blending an active energy ray curable monomer and / or oligomer (B), an active energy ray curable polymer It is preferably used in an amount of 10 parts by mass or less, particularly 6 parts by mass or less, based on 100 parts by mass of (A) and the total amount 100 parts by mass of the active energy ray curable monomer and / or oligomer (B).

In the active energy ray-curable pressure-sensitive adhesive, in addition to the above components, other components may be appropriately blended. As another component, an active energy ray non-hardening polymer component or oligomer component (D), a crosslinking agent (E) etc. are mentioned, for example.

Examples of the active energy ray non-curable polymer component or oligomer component (D) include polyacrylic esters, polyesters, polyurethanes, polycarbonates, polyolefins and the like, and polymers having a weight average molecular weight (Mw) of 3,000 to 2,500,000 or Oligomers are preferred. By blending the component (D) in the active energy ray-curable pressure-sensitive adhesive, the tackiness and releasability before curing, the strength after curing, the adhesiveness with other layers, the storage stability and the like can be improved. The compounding quantity of the said component (D) is not specifically limited, With respect to 100 mass parts of active energy ray curable polymers (A), it determines suitably in more than 0 mass part and 50 mass parts or less.

As a crosslinking agent (E), the polyfunctional compound which has the reactivity with the functional group which the active energy ray curable polymer (A) etc. have can be used. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, Reactive phenol resin etc. can be mentioned.

The compounding amount of the crosslinking agent (E) is preferably 0.01 parts by mass or more, particularly preferably 3 parts by mass or more, per 100 parts by mass of the active energy ray-curable polymer (A). The amount of the crosslinking agent (E) is preferably 20 parts by mass or less, and more preferably 17 parts by mass or less, based on 100 parts by mass of the active energy ray-curable polymer (A).

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

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

As the monomer and / or oligomer having at least one or more active energy ray-curable groups, the same one as the component (B) described above can be selected. The compounding ratio of the active energy ray non-curable polymer component to the monomer and / or oligomer having at least one or more active energy ray curable groups is at least 1 with respect to 100 parts by mass of the active energy ray non-curable polymer component. It is preferable that it is 1 mass part or more of a monomer and / or oligomer which has two or more active energy ray curable groups, and it is especially preferable that it is 60 mass parts or more. In addition, the compounding ratio is preferably 200 parts by mass or less of a monomer and / or oligomer having at least one or more active energy ray-curable groups with respect to 100 parts by mass of the active energy ray non-curable polymer component, In particular, the amount is preferably 160 parts by mass or less.

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

The work processing sheet according to the present embodiment has the thickness of the pressure-sensitive adhesive layer, since the oxygen atom ratio at the position 100 nm deep from the pressure-sensitive adhesive surface among the positions in the pressure-sensitive adhesive layer is defined as described above. Naturally, it is 100 nm or more. In particular, the pressure-sensitive adhesive layer is preferably 1.5 μm or more, and more preferably 2 μm or more. Further, the thickness is preferably 50 μm or less, and particularly preferably 40 μm or less. When the thickness of the pressure-sensitive adhesive layer is in the above-mentioned range, it becomes easy to achieve the desired adhesion to the workpiece.

(3) Release sheet In the work processing sheet according to the present embodiment, the release sheet is laminated on the surface for the purpose of protecting the surface until the adhesive surface of the pressure-sensitive adhesive layer is attached to the object to be cut. May be The configuration of the release sheet is optional, and examples thereof include those obtained by release treatment of a plastic film 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, silicone type, fluorine type, long chain alkyl type and the like can be used, and among these, silicone type is preferable because inexpensive and stable performance can be obtained. The thickness of the release sheet is not particularly limited, but is usually 20 μm or more and 250 μm or less.

(4) Other members In the work processing sheet according to the present embodiment, an adhesive layer may be laminated on the adhesive surface of the adhesive layer. In this case, the work processing sheet according to the present embodiment can be used as a dicing / die bonding sheet by providing the adhesive layer as described above. In such a work processing sheet, a cut object is attached to the surface of the adhesive layer opposite to the pressure-sensitive adhesive layer, and the adhesive layer is singulated by dicing the adhesive layer together with the cut object. A chip on which the agent layer is laminated can be obtained. The chip can be easily fixed to an object on which the chip is mounted by the separated adhesive layer. As a material constituting the adhesive layer described above, a material containing a thermoplastic resin and a thermosetting adhesive component having a low molecular weight, a material containing a B-stage (semi-hardened) thermosetting adhesive component, etc. It is preferred to use.

Moreover, in the sheet | seat for work processing which concerns on this embodiment, a protective film formation layer may be laminated | stacked on the adhesive surface in an adhesive layer. In this case, the work processing sheet according to the present embodiment can be used as a protective film forming and dicing sheet. In such a sheet for processing a work, an object to be cut is attached to the surface of the protective film forming layer opposite to the adhesive layer, and the protective film forming layer is diced together with the object to be cut. The chip | tip in which the protective film formation layer was laminated | stacked can be obtained. As the object to be cut, it is preferable to use one having a circuit formed on one side, and in this case, a protective film-forming layer is usually laminated on the side opposite to the side on which the circuit is formed. . The protective film forming layer separated into pieces can be cured at a predetermined timing to form a protective film having sufficient durability on the chip. The protective film-forming layer preferably comprises an uncured curable adhesive.

In addition, although the sheet | seat for work processing which concerns on this embodiment satisfy | fills the reduction rate of the water contact angle and adhesive force mentioned above, the adhesive bond layer or protective film formation layer mentioned above with respect to the adhesive layer is laminated | stacked In the case of the pressure-sensitive adhesive layer before these layers are laminated, the oxygen atom ratio at a position 100 nm deep from the pressure-sensitive adhesive surface may satisfy the above-described range.

3. Method of Manufacturing Sheet for Processing of Work The method of manufacturing a sheet for processing of work according to the present embodiment is not particularly limited. Preferably, the sheet for processing of work according to the present embodiment has a pressure-sensitive adhesive layer laminated on one side of a substrate. It is manufactured by doing.

The lamination of the pressure-sensitive adhesive layer on one side of the substrate can be carried out by a known method. For example, it is preferable to transfer the pressure-sensitive adhesive layer formed on the release sheet to one side of the substrate. In this case, a pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer, and, if desired, a coating liquid containing a solvent or a dispersion medium if desired, may be called a release-treated surface (hereinafter referred to as "release surface" The above coating solution is applied on a die coater, curtain coater, spray coater, slit coater, knife coater or the like to form a coating film, and the coating film is dried to form a pressure-sensitive adhesive layer. be able to. The coating liquid is not particularly limited in its properties as long as it can be applied, and may contain a component for forming a pressure-sensitive adhesive layer as a solute or a dispersoid. The release sheet in this laminate may be released as a process material, or may be used to protect the adhesive surface of the pressure-sensitive adhesive layer until the work processing sheet is attached to a workpiece.

When the coating liquid for forming the pressure-sensitive adhesive layer contains a crosslinking agent, the inside of the coating film can be obtained by changing the above-mentioned drying conditions (temperature, time, etc.) or by separately providing a heat treatment. The crosslinking reaction of the active energy ray curable polymer (A) or the active energy ray non-curable polymer and the crosslinking agent may be advanced to form a crosslinked structure at a desired density in the pressure-sensitive adhesive layer. After laminating the pressure-sensitive adhesive layer on the substrate by the above-mentioned method or the like in order to allow the crosslinking reaction to proceed sufficiently, the obtained work processing sheet is, for example, several days in an environment of 23 ° C. and 50% relative humidity. You may do the curing such as leaving still.

Instead of transferring the pressure-sensitive adhesive layer formed on the release sheet to one side of the substrate as described above, the pressure-sensitive adhesive layer may be formed directly on the substrate. In this case, the coating liquid for forming the pressure-sensitive adhesive layer described above is applied to one side of the substrate to form a coating, and the coating is dried to form the pressure-sensitive adhesive layer.

4. Method of Using a Sheet for Processing a Work The sheet for processing a work according to the present embodiment can be used for processing a work (object to be cut). That is, after the adhesive surface of the work processing sheet according to the present embodiment is attached to the work, the work can be processed on the work processing sheet. According to the said process, the sheet | seat for work processing which concerns on this embodiment can be used as a back grind sheet, a dicing sheet, an expand sheet, a pickup sheet etc. Here, examples of the object to be cut include a semiconductor wafer, a semiconductor member such as a semiconductor package, and a glass member such as a glass plate.

Moreover, when the sheet | seat for workpiece processing which concerns on this embodiment is equipped with the adhesive bond layer mentioned above, the said sheet | seat for workpiece processing can be used as a dicing die bonding sheet. Furthermore, when the work processing sheet according to the present embodiment includes the above-described protective film forming layer, the work processing sheet can be used as a protective film formation and dicing sheet.

In the work processing sheet according to the present embodiment, even when the pressure-sensitive adhesive derived from the pressure-sensitive adhesive layer adheres to the object to be cut, the pressure-sensitive adhesive can be easily removed by flowing water, and It is suppressed that the water resulting from the said flowing water infiltrates into the interface of a sheet | seat and a to-be-cut object, and the interface of the sheet | seat for workpiece processing, and the obtained chip | tip. Therefore, it is preferable to use the sheet for processing a work according to the present embodiment in processing in which flowing water is used, and in particular, it is preferable to use it for dicing involving supplying flowing water to the cut portion is there. That is, the work processing sheet according to the present embodiment is preferably used as a dicing sheet.

When using the sheet | seat for work processing which concerns on this embodiment as a dicing sheet | seat, general conditions can be used as the conditions of dicing and the supply conditions of flowing water. Particularly with regard to the supply conditions of running water, it is preferable to use pure water or the like as the water used. The amount of water supplied is preferably 0.5 L / min or more, and more preferably 1 L / min or more. The amount of water supplied is preferably 2.5 L / min or less, and more preferably 2 L / min or less. In addition, the temperature of water is not specifically limited, For example, it is preferable to set it as about room temperature.

[Method of manufacturing processed work]
In the method of manufacturing a processed work according to an embodiment of the present invention, a bonding step of bonding a work to the surface of the pressure-sensitive adhesive layer of the work processing sheet described above opposite to the base, and work processing The processing step of obtaining the processed work stacked on the work processing sheet by processing the work on the work sheet, and irradiating the pressure-sensitive adhesive layer with an active energy ray to cure the pressure-sensitive adhesive layer And an irradiation step of reducing the adhesion of the work processing sheet to the processed work, and a separation step of separating the processed work from the work processing sheet after the active energy ray irradiation.

The work processing sheet used in the method of manufacturing a processed work of the present embodiment can be used during work processing while suppressing the infiltration of water at the interface between the work processing sheet and the work or the work after processing. The adhesive adhering to the work can be removed well by running water. Therefore, according to the method of manufacturing a processed work of the present embodiment, it is possible to efficiently manufacture the processed work.

Hereinafter, each process in the manufacturing method of the processed workpiece | work of this embodiment is demonstrated.

(1) Bonding process The bonding of the work and the work processing sheet in the bonding process can be performed by a conventionally known method. In addition, when performing dicing of a work in the subsequent processing step, it is preferable to bond a ring frame to the area on the outer peripheral side of the area to which the work is to be bonded on the adhesive layer side of the work processing sheet. . Moreover, the workpiece to be used may be a desired one according to the processed workpiece to be manufactured, and as a specific example, the above-mentioned one can be used.

(2) Processing Step In the processing step, desired processing can be performed on the workpiece, and for example, back grinding, dicing, etc. can be performed. These processes can be performed by a conventionally known method.

In addition, when performing blade dicing using a rotating blade as the above-mentioned processing, in general, a part of the pressure-sensitive adhesive layer in the work processing sheet is cut together with the work. At this time, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be wound up by a blade and attached to the processed work. However, in the work processing sheet used in the method of manufacturing a processed work of the present embodiment, as described above, the adhered pressure sensitive adhesive can be removed well by flowing water. From this point of view, the processing in the present embodiment is preferably dicing, and particularly preferably blade dicing using a rotating blade.

(3) Irradiation process In the irradiation process, as long as the adhesion of the work processing sheet to the processed work can be reduced to a desired degree, the conditions for irradiation of the active energy ray are not limited, and based on the conventionally known methods. It can be carried out. Examples of the type of active energy ray to be used include ionizing radiation, that is, X-rays, ultraviolet rays, electron beams, etc. Among them, ultraviolet rays which are relatively easy to introduce irradiation equipment are preferable.

(4) Separation step In the separation step, separation is performed according to the type of processing and the obtained processed workpiece. For example, when dicing is performed as processing and a chip in which the work is separated is obtained by the dicing, the obtained chips are individually obtained from the work processing sheet using a conventionally known pickup device. Pick up. Moreover, in order to make the said pickup easy, the sheet | seat for workpiece processing may be expanded, and you may space apart processed workpieces.

(5) Others In the method of manufacturing a processed work of the present embodiment, steps other than the above-described steps may be provided. For example, after the bonding step, there may be provided a transport step of transporting the laminate of the obtained work and the work processing sheet to a predetermined position, or a storage step of storing the laminate for a predetermined period. In addition, after the separation step, a mounting step or the like may be provided in which the obtained processed workpiece is mounted on a predetermined base or the like.

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

For example, another layer may be provided between the substrate and the pressure-sensitive adhesive layer, or on the surface of the substrate opposite to the pressure-sensitive adhesive layer.

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

Example 1
(1) Preparation of Pressure-Sensitive Adhesive Composition To an acrylic copolymer obtained by copolymerizing 80 parts by mass of methyl acrylate and 20 parts by mass of 2-hydroxyethyl acrylate, 100 g of the acrylic copolymer An active energy ray-curable polymer was obtained by reacting 21.4 g (corresponding to 80 mol% with respect to the mole number of 2-hydroxyethyl acrylate) of methacryloyloxyethyl isocyanate (MOI). . It was 600,000 when the weight average molecular weight (Mw) of this active energy ray curable polymer was measured by the method mentioned later.

100 parts by mass of the obtained active energy ray-curable polymer (in terms of solid content, hereinafter the same) and 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name “IRGACURE 184”) as a photopolymerization initiator A crosslinker and 3.11 parts by mass of toluene diisocyanate (manufactured by Tosoh Corporation, product name “Coronato L”) as a crosslinking agent were mixed in a solvent to obtain a pressure-sensitive adhesive composition.

(2) Formation of Pressure-Sensitive Adhesive Layer With respect to the release surface of a release sheet (Lintec Co., Ltd., product name “SP-PET 381031”) in which a silicone release agent layer is formed on one side of a 38 μm thick polyethylene terephthalate film. The above-mentioned pressure-sensitive adhesive composition was applied, dried by heating, and then aged under conditions of 23 ° C. and 50% RH for 7 days to form a 5 μm-thick pressure-sensitive adhesive layer on the release sheet.

(3) Preparation of Workpiece Processing Sheet The surface of the pressure-sensitive adhesive layer formed in the above step (2) opposite to the release sheet, and a 80 μm-thick ethylene-methacrylic acid copolymer (EMAA) film as a substrate The sheet | seat for workpiece processing was obtained by bonding together to one side of.

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

[Examples 2 to 5 and Comparative Examples 1 to 3]
A work processing sheet was produced in the same manner as in Example 1 except that the composition of the acrylic copolymer was changed as shown in Table 1, and the content of the crosslinking agent was changed as shown in Table 2.

[Test Example 1] (Measurement of oxygen atom ratio)
The release sheet was peeled off from the work processing sheet manufactured in the examples and comparative examples, and the oxygen atom ratio (%) in the exposed surface (adhesive surface) of the exposed pressure-sensitive adhesive layer and the adhesion at a depth of 100 nm from the exposed surface The oxygen atom ratio (%) in the agent layer was measured using an X-ray photoelectron spectrometer (manufactured by ULVAC-PHI, product name “PHI Quantera SXM”), and the oxygen atom ratio at “0 nm position” ( % And the oxygen atomic ratio (%) at the position of 100 nm. The results are shown in Table 3.

[Test Example 2] (Measurement of Water Contact Angle)
The release sheet was peeled off from the work processing sheet manufactured in the examples and comparative examples, and the water contact angle (°) at the exposed surface of the exposed adhesive layer was measured using a fully automatic contact angle measuring meter (Kyowa Interface Science Co., Ltd.) It measured on condition of the following using product name "DM-701". The results are shown in Table 3.
Droplet volume of purified water: 2 μl
・ Measurement time: 3 seconds after dropping ・ Image analysis method: θ / 2 method

[Test Example 3] (Measurement of Adhesive Strength)
By peeling the release sheet from the work processing sheet manufactured in the example and the comparative example, overlapping the exposed surface of the exposed adhesive layer on the mirror surface of the mirror-finished 6-inch silicon wafer, and reciprocating a 2 kg roller one time Load was applied for bonding and left for 20 minutes. Thereafter, the work processing sheet is peeled from the silicon wafer at a peeling speed of 300 mm / min and a peeling angle of 180 °, and the adhesive force F1 (mN / 25 mm) to the silicon wafer by a 180 ° peeling method according to JIS Z0237: 2009. Was measured. The results are shown in Table 3.

Further, the release sheet was peeled off from the work processing sheet produced in the example and the comparative example, and the exposed surface of the exposed pressure-sensitive adhesive layer was immersed in distilled water at 23 ° C. for 12 hours, and then dried at 23 ° C. for 24 hours. Thereafter, the exposed surface was superposed on the mirror surface of a 6-inch silicon wafer mirror-finished, and a load of 2 kg was made to reciprocate by 1 reciprocation for bonding, and left for 20 minutes. Subsequently, the work processing sheet is peeled from the silicon wafer at a peeling speed of 300 mm / min and a peeling angle of 180 °, and the silicon wafer after the above immersion and drying is performed by the 180 ° peeling method according to JIS Z0237: 2009. The adhesive force F2 (mN / 25 mm) was measured. The results are shown in Table 3.

Furthermore, using the values of adhesive force F1 (mN / 25 mm) and adhesive force F2 (mN / 25 mm) obtained as described above, the following formula (1)
Decreasing rate of adhesion (%) = {(F1-F2) / F1} × 100 (1)
The reduction rate (%) of the adhesive strength was calculated from The results are shown in Table 3.

[Test Example 4] (Evaluation of removability of adhesive)
Release sheet in which a silicone-based release agent layer is formed on one side of a 38 μm thick polyethylene terephthalate film (the adhesive agent manufactured by Lintec Co., Ltd., product name “SP-PET 38 1031”) The adhesive layer of 5 micrometers in thickness was formed on the peeling sheet by apply | coating to the peeling surface of 5, and making it dry by heating. From the thus-obtained laminate of the pressure-sensitive adhesive layer and the release sheet, 20 pieces of the laminate having a size of 5 mm × 5 mm were cut out.

Subsequently, the surfaces of the 20 small pieces obtained as described above on the pressure-sensitive adhesive layer side are attached to the polished surface of a # 2000 polished 6-inch silicon wafer (thickness: 150 μm), and then from the pressure-sensitive adhesive layer Each release sheet was peeled off. In the case of the said sticking, small pieces were stuck so that the space | interval of 1 mm or more might be left.

After that, the release sheet is peeled off from the work processing sheet manufactured in the example and the comparative example, and a tape mounter (product name: "Adwill RAD 2500 m / 12" manufactured by Lintec Corporation) is used on the exposed surface of the exposed adhesive layer. The surface opposite to the surface to which the small piece of the 6-inch silicon wafer was attached was attached. Subsequently, using a dicing apparatus (product name "DFD-6361" manufactured by Disco Corporation), an operation simulating dicing performed from the 6-inch silicon wafer side is performed while supplying flowing water to the cutting unit under the following operating conditions The

<Operating conditions>
・ Dicing device: made by DISCO DFD-6361
・ Blade: Disco made NBC-2H 2050 27HECC
・ Blade width: 0.025 to 0.030 mm
-Cutting edge amount: 0.640 to 0.760 mm
-Blade rotation speed: 50000 rpm
・ Cutting speed: 20 mm / sec
・ Blade height: 5 mm
・ Flow water supply amount: 1.0 L / min
・ Flowing water temperature: Room temperature ・ Cut size: 10 mm × 10 mm
The above "blade height: 5 mm" means that the distance between the blade and the 6 inch silicon wafer is 5 mm, and it is clear from this that in the above operation, the 6 inch silicon wafer with the blade is used. There is no disconnection.

After completion of dicing, the presence or absence of the adhesive derived from the above-mentioned small pieces remaining on the silicon wafer was confirmed, and the removability of the adhesive was evaluated based on the following criteria. The results are shown in Table 3.
○: no adhesive remained.
X: At least a part of the adhesive remained.

[Test Example 5] (Evaluation of water infiltration)
The release sheet was peeled off from the work processing sheet manufactured in Examples and Comparative Examples, and the exposed surface of the exposed adhesive layer was exposed using a tape mounter (manufactured by Lintec Corporation, product name "Adwill RAD 2500 m / 12") A polished surface of 2000 polished 6 inch silicon wafer (thickness: 150 μm) was attached. Subsequently, using a dicing apparatus (manufactured by Disco, product name “DFD-6361”), dicing was performed from the 6-inch silicon wafer side while supplying flowing water to the cutting portion under the following dicing conditions.

<Dicing conditions>
・ Dicing device: made by DISCO DFD-6361
・ Blade: Disco made NBC-2H 2050 27HECC
・ Blade width: 0.025 to 0.030 mm
-Cutting edge amount: 0.640 to 0.760 mm
-Blade rotation speed: 50000 rpm
・ Cutting speed: 20 mm / sec
· Depth of cut: 15 μm from the surface on the adhesive layer side of the work processing sheet
・ Flow water supply amount: 1.0 L / min
・ Flowing water temperature: Room temperature ・ Cut size: 10 mm × 10 mm

After completion of dicing, all chips obtained are removed from the work processing sheet, and the surface on the adhesive layer side of the work processing sheet is a digital microscope (product name "VHX-1000" manufactured by Keyence Corporation, magnification: 500) The water infiltration at the interface between the chip and the work processing sheet was evaluated based on the following criteria. The results are shown in Table 3.
Good: There were no traces of water infiltration on the surface on the adhesive layer side of the work processing sheet.
X: There was a trace of water penetration on the surface on the adhesive layer side of the work processing sheet.

The details of the abbreviations and the like described in Table 1 are as follows.
BA: butyl acrylate MMA: methyl methacrylate DMAA: dimethyl acrylamide MA: methyl acrylate 2 MEA: 2-methoxyethyl acrylate MTG: methoxyethylene glycol acrylate HEA: 2-hydroxyethyl acrylate MOI: methacryloyl oxyethyl isocyanate

As can be seen from Table 3, in the work processing sheet obtained in the example, the adhesive could be removed well by flowing water, and the entry of water could be suppressed well.

The work processing sheet of the present invention can be suitably used for dicing.

Claims (10)

1. A work processing sheet comprising: a base material; and an adhesive layer laminated on one side of the base material,
   The oxygen atom ratio measured by X-ray photoelectron spectroscopy analysis at a position at a depth of 100 nm from the surface of the pressure-sensitive adhesive layer opposite to the surface of the pressure-sensitive adhesive layer is 20 atomic% or more, 29 A sheet for processing a work characterized by having an atomic percent or less.
2. The work processing sheet according to claim 1, wherein a thickness of the pressure-sensitive adhesive layer is 1.5 μm or more and less than 50 μm.
3. The water contact angle of the surface on the opposite side to the said base material in the said adhesive layer is 50 degrees or more and 80 degrees or less, The sheet | seat for workpiece processing of Claim 1 or 2 characterized by the above-mentioned.
4. The adhesion of the work processing sheet to the silicon wafer is F1, and the work processing sheet is immersed in distilled water at 23 ° C. for 12 hours and further dried at 23 ° C. for 24 hours, the silicon of the work processing sheet Assuming that the adhesive force to the wafer is F2, the following equation (1)
   Decreasing rate of adhesion (%) = {(F1-F2) / F1} × 100 (1)
   The work processing sheet according to any one of claims 1 to 3, wherein the decrease rate of the adhesive force calculated from the above is 20% or more and 50% or less.
5. The said adhesive force F1 is 1000 mN / 25 mm or more and 10000 mN / 25 mm or less, The sheet | seat for workpiece | work processing of Claim 4 characterized by the above-mentioned.
6. The work processing sheet according to claim 4 or 5, wherein the adhesive force F2 is 900 mN / 25 mm or more and 8000 mN / 25 mm or less.
7. The work processing sheet according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive.
8. The active energy ray-curable pressure-sensitive adhesive comprises, as monomer units constituting a polymer, methyl acrylate, 2-methoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate and methoxy ethylene glycol (meth) acrylate The work processing sheet according to claim 7, which is a pressure-sensitive adhesive formed from a pressure-sensitive adhesive composition containing an acrylic copolymer containing at least one selected from the following.
9. The work processing sheet according to any one of claims 1 to 8, which is a dicing sheet.
10. A bonding step of bonding a work with a surface of the pressure-sensitive adhesive layer of the work processing sheet according to any one of claims 1 to 9 opposite to the base material,
    A processing step of obtaining a processed work laminated on the work processing sheet by processing the work on the work processing sheet;
    An irradiation step of irradiating the pressure-sensitive adhesive layer with an active energy ray to cure the pressure-sensitive adhesive layer and reducing the adhesion of the work processing sheet to the processed work;
    A method of manufacturing a processed work comprising: separating the processed work from the sheet for processing a work after irradiation of active energy rays.