Workpiece processing sheet

Abstract

To provide a work processing sheet capable of satisfactorily suppressing the occurrence of adhesive residue.SOLUTION: A work processing sheet includes a substrate and an adhesive layer laminated on one side of the substrate, and the substrate includes a resin layer formed from a resin composition containing a vinyl chloride resin and a stabilizer, and the stabilizer includes at least one of a saturated fatty acid metal salt having 12 or more and less than 18 carbon atoms and an unsaturated fatty acid metal salt having 12 or more and less than 20 carbon atoms.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a workpiece processing sheet used for processing a workpiece such as a semiconductor wafer. [Background technology]

[0002] Semiconductor wafers such as silicon and gallium arsenide and various packages are manufactured in a large diameter state, cut (diced) into chips, peeled (picked up), and then transferred to the next process, the mounting process. At this time, the workpieces such as semiconductor wafers are stacked on an adhesive sheet (hereinafter sometimes referred to as a "workpiece processing sheet") that has a base material and an adhesive layer, and are processed by back grinding, dicing, cleaning, drying, expanding, picking up, mounting, etc.

[0003] In the above-mentioned pick-up process, the chips obtained by dicing are usually separated individually from the workpiece processing sheet by a suction collet, etc. At this time, in order to facilitate the separation, the chips are pushed up by a pin, needle, etc. from the side of the workpiece processing sheet opposite to the side on which the chips are stacked.

[0004] In addition, the collection of chips obtained by dicing on the workpiece processing sheet may be transferred to another workpiece processing sheet (pickup sheet), and then the pick-up process may be performed on the pick-up sheet.

[0005] During the above pick-up or transfer, the adhesive layer may peel off from the substrate constituting the workpiece processing sheet, causing the adhesive constituting the adhesive layer to adhere to the chip (residual adhesive). Such residual adhesive tends to occur particularly easily when the substrate is mainly made of vinyl chloride resin. If the chip is incorporated into a product with the adhesive still attached, it will have a significant adverse effect on the performance of the product, so it is necessary to suppress the occurrence of residual adhesive.

[0006] In order to prevent the above-mentioned adhesive residue from occurring, Patent Document 1 discloses an adhesive tape for semiconductor processing that has a specific adhesive layer on a polyvinyl chloride film. Patent Document 2 discloses an adhesive tape for semiconductor wafer processing that has a specific adhesive applied to a specific soft polyvinyl chloride resin film substrate. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2018-137376 A [Patent Document 2] JP 2006-36834 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, even if conventional workpiece processing sheets as in Patent Documents 1 and 2 are used, the problem of adhesive residue cannot be fully solved. Therefore, there is a demand for the development of a workpiece processing sheet that can further suppress the occurrence of adhesive residue.

[0009] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a work processing sheet that can effectively prevent the occurrence of glue residue. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, firstly, the present invention provides a workpiece processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate, wherein the substrate comprises a resin layer formed from a resin composition containing a vinyl chloride resin and a stabilizer, and the stabilizer comprises at least one of a saturated fatty acid metal salt having a carbon number of 12 or more and less than 18 and an unsaturated fatty acid metal salt having a carbon number of 12 or more and less than 20 (Invention 1).

[0011] The workpiece processing sheet according to the above invention (Invention 1) contains a resin composition for forming the base material which contains a saturated fatty acid metal salt or an unsaturated fatty acid metal salt having the above-mentioned carbon number as a stabilizer, and therefore, even though the base material is mainly made of vinyl chloride resin, the occurrence of residual glue can be effectively suppressed.

[0012] In the above invention (Invention 1), the content of the stabilizer in the resin composition is preferably 0.01 parts by mass or more and 8 parts by mass or less relative to 100 parts by mass of the vinyl chloride resin (Invention 2).

[0013] In the above inventions (Inventions 1 and 2), the resin composition preferably contains a plasticizer (Invention 3).

[0014] In the above inventions (Inventions 1 to 3), the substrate preferably consists of a single resin layer (Invention 4).

[0015] In the above inventions (Inventions 1 to 3), it is preferable that the substrate is made of a plurality of layers, at least one of which is the resin layer (Invention 5).

[0016] In the above inventions (Inventions 1 to 5), the pressure-sensitive adhesive layer is preferably composed of an active energy ray-curable pressure-sensitive adhesive (Invention 6).

[0017] In the above inventions (Inventions 1 to 6), a dicing sheet is preferable (Invention 7). Effect of the Invention

[0018] The workpiece processing sheet according to the present invention can effectively prevent the occurrence of adhesive residue. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described. The workpiece processing sheet according to the present embodiment includes a substrate and a pressure-sensitive adhesive layer laminated on one side of the substrate. The substrate includes a resin layer formed from a resin composition containing a vinyl chloride resin and a stabilizer.

[0020] Here, the substrate in this embodiment may be composed of a single layer of the resin layer, or may be composed of multiple layers, at least one of which is the resin layer.

[0021] In the workpiece processing sheet according to this embodiment, the stabilizer contains at least one of a saturated fatty acid metal salt having a carbon number of 12 or more and less than 18 and an unsaturated fatty acid metal salt having a carbon number of 12 or more and less than 20. In the workpiece processing sheet according to this embodiment, by using these saturated fatty acid metal salts and unsaturated fatty acid metal salts as stabilizers, the occurrence of glue residue during pick-up can be effectively suppressed.

[0022] The reason why the occurrence of adhesive residue can be suppressed in this way is thought to be, but is not limited to, the following. In a substrate made mainly of a vinyl chloride resin, the heat treatment required for film formation may cause chlorine to be liberated from the vinyl chloride resin. Stabilizers are generally used to capture this free chlorine and suppress deterioration of the substrate. However, the present inventors discovered that conventional stabilizers tend to migrate (bleed out) from the inside of the substrate to the surface, and the bleed-out stabilizer reduces the adhesion between the substrate and the adhesive layer, causing adhesive residue. On the other hand, the above-mentioned saturated fatty acid metal salt and unsaturated fatty acid metal salt in this embodiment are difficult to bleed out, and therefore, while fully exerting the function as a stabilizer, the adhesion between the substrate and the adhesive layer is not reduced, and the occurrence of adhesive residue can be well suppressed.

[0023] 1. Composition of workpiece processing sheet (1) Base material As described above, the substrate in this embodiment includes a resin layer formed from a resin composition containing a vinyl chloride resin and a stabilizer.

[0024] As described above, the substrate in this embodiment may be a single layer of the resin layer, or may be a multi-layer substrate having at least one of the resin layers. A substrate made of a single resin layer is preferable in terms of reducing manufacturing costs. On the other hand, a substrate made of multiple layers is preferable in terms of achieving both the adhesive transfer suppression effect mainly due to the resin layer and the desired effect due to layers other than the resin layer.

[0025] When the substrate has a layer other than the resin layer, the material of the layer is not particularly limited as long as it allows the formation of the layer and the substrate.

[0026] (1-1) Vinyl chloride resin The vinyl chloride resin in this embodiment means all polymers having a repeating unit represented by -CH2-CHCl-, and includes homopolymers of vinyl chloride, copolymers of vinyl chloride and polymerizable monomers such as ethylene-vinyl chloride copolymers, modified homopolymers or copolymers such as chlorinated vinyl chloride copolymers, and chlorinated polyolefins structurally similar to vinyl chloride resins such as chlorinated polyethylene. The vinyl chloride resin contained in the resin composition for forming the resin layer in this embodiment is not particularly limited, and any of the above-mentioned resins may be used. The above-mentioned vinyl chloride resins may be used alone or in combination of two or more.

[0027] The vinyl chloride resin has an average degree of polymerization of preferably 300 or more, more preferably 800 or more. The vinyl chloride resin has an average degree of polymerization of preferably 2500 or less, more preferably 2000 or less. When the average degree of polymerization is within the above range, the resin has excellent moldability and processability, and can be easily processed into a uniform thin film. The average degree of polymerization of the vinyl chloride resin is a value measured in accordance with JIS K6720-2:1999.

[0028] (1-2) Stabilizers As described above, the stabilizer in this embodiment contains at least one of a saturated fatty acid metal salt having 12 or more and less than 18 carbon atoms and an unsaturated fatty acid metal salt having 12 or more and less than 20 carbon atoms.

[0029] Examples of saturated fatty acids constituting saturated fatty acid metal salts having 12 or more and less than 18 carbon atoms include lauric acid (carbon number 12), myristic acid (carbon number 14), palmitic acid (carbon number 16), and the like.

[0030] Examples of unsaturated fatty acids that constitute unsaturated fatty acid metal salts having 12 or more and less than 20 carbon atoms include myristoleic acid (carbon number 14), palmitoleic acid (carbon number 16), oleic acid (carbon number 18), and elaidic acid (carbon number 18).

[0031] Examples of metals constituting the saturated fatty acid metal salts and the unsaturated fatty acid metal salts include zinc, barium, sodium, potassium, magnesium, calcium, aluminum, lead, chromium, molybdenum, tungsten, manganese, iron, and cobalt.

[0032] In particular, preferred examples of the saturated fatty acid metal salt in this embodiment include zinc laurate and zinc palmitate, and preferred examples of the unsaturated fatty acid metal salt in this embodiment include zinc oleate.

[0033] In the present embodiment, the saturated fatty acid metal salt and the unsaturated fatty acid metal salt may be used alone or in combination of two or more kinds.

[0034] In addition, as the stabilizer in this embodiment, other stabilizers may be used in addition to the saturated fatty acid metal salt and the unsaturated fatty acid metal salt.

[0035] The content of the stabilizer in the resin composition for forming the resin layer is preferably 0.01 parts by mass or more, particularly preferably 0.5 parts by mass or more, relative to 100 parts by mass of the vinyl chloride resin. The content of the stabilizer in the resin composition is preferably 8 parts by mass or less, particularly preferably 5 parts by mass or less, relative to 100 parts by mass of the vinyl chloride resin. By having the content of the stabilizer in the above range, it is possible to effectively suppress the occurrence of adhesive residue while sufficiently suppressing the deterioration of the substrate.

[0036] In addition, whether or not a substrate constituting a certain workpiece processing sheet contains the above-mentioned saturated fatty acid metal salt or unsaturated fatty acid metal salt can be confirmed from the mass spectrum obtained by analyzing the substrate by time-of-flight secondary ion mass spectrometry (TOF-SIMS) as described in the test example described later. In particular, this analysis makes it possible to clearly determine whether the number of carbon atoms is 16 or 18, and whether the fatty acid is saturated or unsaturated.

[0037] (1-3) Other ingredients The resin composition for forming the resin layer may contain other components in addition to the vinyl chloride resin and stabilizer described above. In particular, the resin composition may contain components used in the base material of general workpiece processing sheets.

[0038] Examples of such components include various additives such as plasticizers, auxiliaries, pigments, antistatic agents, flame retardants, lubricants, antioxidants, infrared absorbers, ultraviolet absorbers, etc. The content of these additives is not particularly limited, but is preferably within a range in which the substrate exhibits the desired function.

[0039] In particular, the resin composition for forming the resin layer preferably contains a plasticizer. By containing a plasticizer, the substrate is likely to have good flexibility. Examples of the plasticizer include phthalic acid, adipic acid, polyester, etc.

[0040] When the resin composition for forming the resin layer contains a plasticizer, the content of the plasticizer in the resin composition is preferably 18 parts by mass or more, particularly preferably 25 parts by mass or more, relative to 100 parts by mass of the vinyl chloride resin. The content of the plasticizer in the resin composition is preferably 60 parts by mass or less, particularly preferably 55 parts by mass or less, relative to 100 parts by mass of the vinyl chloride resin. By having the content of the plasticizer in the above range, the substrate is likely to have good flexibility.

[0041] (1-4) Surface treatment of substrate The surface of the substrate on which the adhesive layer is laminated may be subjected to a surface treatment such as a primer treatment, a corona treatment, a plasma treatment, a roughening treatment (matt processing) or the like in order to enhance adhesion to the adhesive layer. Examples of the roughening treatment include an embossing method and a sandblasting method. Among these, the embossing method is preferable.

[0042] (1-5) Manufacturing method of substrate The method for producing the substrate in this embodiment is not particularly limited as long as the above-mentioned resin composition is used, and for example, melt extrusion methods such as the T-die method and the round die method, calendar method, solution method such as the dry method and the wet method, etc. can be used. Among these, from the viewpoint of efficiently producing the substrate, it is preferable to adopt the melt extrusion method, and it is particularly preferable to adopt the T-die method.

[0043] When a substrate consisting of only a single resin layer is manufactured by a melt extrusion method, the resin composition is kneaded, and the kneaded product obtained is directly or once made into pellets, and then film-formed using a known extruder. In this case, it is preferable to immediately cool the extruded product to room temperature using a cooling roll or the like immediately after extrusion using the extruder, from the viewpoint of easily achieving the above-mentioned degree of crystallinity.

[0044] In addition, when a multi-layered substrate is manufactured by melt extrusion, the components constituting each layer are mixed, and the resulting mixture is directly or once made into pellets, and then the multi-layers are simultaneously extruded using a known extruder to form a film. In this case, it is preferable to immediately cool to room temperature immediately after extrusion, from the viewpoint of easily achieving the above-mentioned crystallinity, as in the above.

[0045] (1-6) Thickness of the substrate In this embodiment, the thickness of the base material is preferably 25 μm or more, and particularly preferably 50 μm or more. The thickness of the base material is preferably 200 μm or less, and particularly preferably 150 μm or less. When the thickness of the base material is 25 μm or more, the work processing sheet is likely to have a moderate strength, and the work fixed on the work processing sheet is likely to be well supported. When the thickness of the base material 11 is 200 μm or less, the thickness of the work processing sheet is likely to have good flexibility, and for example, it is likely to be well expanded.

[0046] (2) Adhesive layer The adhesive constituting the adhesive layer in this embodiment is not particularly limited as long as it can exert sufficient adhesive strength to the adherend (particularly, sufficient adhesive strength to the workpiece for processing the workpiece). Examples of the adhesive constituting the adhesive layer include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, polyvinyl ether adhesives, etc. Among these, it is preferable to use acrylic adhesives from the viewpoint of easily exerting the desired adhesive strength.

[0047] The adhesive constituting the adhesive layer in this embodiment may be an adhesive that does not have active energy ray curability, but is preferably an adhesive that has active energy ray curability (hereinafter, may be referred to as an "active energy ray curable adhesive"). Since the adhesive layer is composed of an active energy ray curable adhesive, the adhesive layer can be cured by irradiation with active energy rays, and the adhesive strength of the workpiece processing sheet to the adherend can be easily reduced. In particular, irradiation with active energy rays makes it possible to easily separate the processed workpiece from the workpiece processing sheet.

[0048] The active energy ray curable adhesive constituting the adhesive layer may be one that mainly comprises a polymer having active energy ray curability, or may be one that mainly comprises a mixture of a non-active energy ray curable polymer (a polymer that does not have active energy ray curability) and a monomer and / or oligomer having at least one or more active energy ray curable groups. The active energy ray curable adhesive 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.

[0049] The active energy ray curable polymer is preferably a (meth)acrylic acid ester polymer (hereinafter sometimes referred to as "active energy ray curable polymer") having a functional group (active energy ray curable group) having active energy ray curability introduced into a side chain. This active energy ray curable polymer is preferably obtained by reacting an acrylic polymer having a functional group-containing monomer unit with an unsaturated group-containing compound having a functional group bonded to the functional group. In this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms. Furthermore, the term "polymer" also includes the concept of "copolymer".

[0050] The acrylic polymer having the functional group-containing monomer unit described above may be obtained by polymerizing other monomers together with the functional group-containing monomer. As such functional group-containing monomers and other monomers, as well as the unsaturated group-containing compounds described above, known compounds can be used, for example, those disclosed in International Publication No. 2018 / 084021.

[0051] The weight average molecular weight of the active energy radiation curable polymer is preferably 10,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more. The weight average molecular weight is preferably 1,500,000 or less, and even more preferably 1,000,000 or less. The weight average molecular weight (Mw) in this specification is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0052] As the above-mentioned active energy ray non-curable polymer component, for example, the above-mentioned acrylic polymer before being reacted with the unsaturated group-containing compound can be used.

[0053] The weight average molecular weight of the acrylic polymer as the non-curable active energy ray polymer component is preferably 10,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more. The weight average molecular weight is preferably 1,500,000 or less, and even more preferably 1,000,000 or less.

[0054] As the above-mentioned monomer and / or oligomer having at least one active energy ray-curable group, for example, an ester of a polyhydric alcohol and (meth)acrylic acid can be used.

[0055] When ultraviolet rays are used as the active energy rays for curing the active energy ray-curable adhesive, it is preferable to add a photopolymerization initiator to the adhesive. In addition, the adhesive may also contain an active energy ray non-curable polymer component or oligomer component, a crosslinking agent, etc.

[0056] The thickness of the adhesive layer in this embodiment is preferably 1 μm or more, particularly preferably 3 μm or more, and more preferably 5 μm or more. The thickness of the adhesive layer is preferably 70 μm or less, particularly preferably 30 μm or less, and more preferably 10 μm or less. By having the thickness of the adhesive layer in the above-mentioned range, the work processing sheet according to this embodiment can easily exhibit the desired adhesiveness.

[0057] (3) Release sheet In the workpiece processing sheet of this embodiment, a release sheet may be laminated to the side of the adhesive layer opposite the substrate (hereinafter sometimes referred to as the "adhesive side") in order to protect said side until it is attached to the workpiece.

[0058] The release sheet may have any structure, and may be, for example, a plastic film that has been subjected to a release treatment using 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. The release agent may be silicone-based, fluorine-based, or long-chain alkyl-based, and among these, silicone-based, which is inexpensive and provides stable performance, is preferred.

[0059] There is no particular limitation on the thickness of the release sheet, and it may be, for example, 20 μm or more and 250 μm or less.

[0060] (4)Other In the workpiece processing sheet according to this embodiment, an adhesive layer may be laminated on the surface of the adhesive layer opposite to the substrate. In this case, the workpiece processing sheet according to this embodiment can be used as a dicing die bonding sheet. In this sheet, a workpiece is attached to the surface of the adhesive layer opposite to the adhesive layer, and the adhesive layer is diced together with the workpiece to obtain a chip on which the individualized adhesive layer is laminated. The individualized adhesive layer makes it possible for the chip to be easily fixed to the object on which the chip is mounted. As the material constituting the above-mentioned adhesive layer, it is preferable to use one containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, one containing a B-stage (semi-cured) thermosetting adhesive component, or the like.

[0061] In addition, in the workpiece processing sheet according to this embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer. In this case, the workpiece processing sheet according to this embodiment can be used as a sheet for forming a protective film and dicing. In such a sheet, a workpiece 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 workpiece to obtain a chip on which the individualized protective film forming layer is laminated. As the workpiece, it is preferable to use one having a circuit formed on one side, and in this case, the protective film forming layer is usually laminated on the surface opposite to the surface on which the circuit is formed. The individualized protective film forming layer can be cured at a predetermined timing to form a protective film having sufficient durability on the chip. The protective film forming layer is preferably made of an uncured curable adhesive.

[0062] 2. Manufacturing method of workpiece processing sheet The manufacturing method of the workpiece processing sheet according to the present embodiment is not particularly limited. For example, it is preferable to obtain the workpiece processing sheet by forming an adhesive layer on a release sheet, and then laminating one side of a substrate on the side of the adhesive layer opposite to the release sheet.

[0063] The above-mentioned pressure-sensitive adhesive layer can be formed by a known method. For example, a coating liquid containing a pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer and, if desired, a solvent or a dispersion medium is prepared. Then, the coating liquid is applied to the surface having releasability of the release sheet (hereinafter, sometimes referred to as the "release surface"). Then, the obtained coating film is dried to form the pressure-sensitive adhesive layer.

[0064] The coating of the above-mentioned coating liquid can be carried out 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. The coating liquid is not particularly limited in its properties as long as it can be coated, and may contain the components for forming the adhesive layer as a solute or as a dispersoid. The release sheet may be peeled off as a process material, or may protect the adhesive layer until it is attached to the adherend.

[0065] When the adhesive composition for forming the adhesive layer contains the above-mentioned crosslinking agent, it is preferable to change the above-mentioned drying conditions (temperature, time, etc.) or provide a separate heat treatment to advance the crosslinking reaction between the polymer component in the coating film and the crosslinking agent, and form a crosslinked structure with a desired density in the adhesive layer. Furthermore, in order to advance the above-mentioned crosslinking reaction sufficiently, after laminating the adhesive layer and the substrate, curing may be performed by leaving the adhesive layer to stand for several days in an environment of 23°C and a relative humidity of 50%.

[0066] 3. How to use the workpiece processing sheet The workpiece processing sheet according to this embodiment can be used for processing a workpiece such as a semiconductor wafer. That is, after the adhesive surface of the workpiece processing sheet according to this embodiment is attached to the workpiece, the workpiece can be processed on the workpiece processing sheet. Depending on the processing, the workpiece processing sheet according to this embodiment can be used as a back grinding sheet, a dicing sheet, an expanding sheet, a pick-up sheet, or the like. Here, examples of the workpiece include semiconductor members such as semiconductor wafers and semiconductor packages, and glass members such as glass plates.

[0067] As described above, the workpiece processing sheet according to this embodiment can effectively suppress the occurrence of glue residue when picking up workpieces (chips, etc.) that have been divided by dicing. Therefore, the workpiece processing sheet according to this embodiment is particularly suitable for use as a dicing sheet, an expanding sheet, and a pick-up sheet among the above-mentioned workpiece processing sheets.

[0068] In addition, when the workpiece processing sheet according to this embodiment has the above-mentioned adhesive layer, the workpiece processing sheet can be used as a dicing / die bonding sheet. Furthermore, when the workpiece processing sheet according to this embodiment has the above-mentioned protective film forming layer, the workpiece processing sheet can be used as a protective film forming / dicing sheet.

[0069] In addition, when the adhesive layer in the workpiece processing sheet according to this embodiment is composed of the above-mentioned active energy ray curable adhesive, it is also preferable to irradiate the adhesive layer with active energy rays during use as follows. That is, when the processing of the workpiece is completed on the workpiece processing sheet and the processed workpiece is to be separated from the workpiece processing sheet, it is preferable to irradiate the adhesive layer with active energy rays before the separation. This hardens the adhesive layer, and the adhesive force of the adhesive sheet to the processed workpiece is reduced well, making it easy to separate the processed workpiece.

[0070] The above-described embodiments are described for the purpose of facilitating understanding of the present invention, and are not described for the purpose of limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0071] For example, another layer may be laminated between the substrate and the adhesive layer in the workpiece processing sheet according to this embodiment, or on the surface of the substrate opposite the adhesive layer. EXAMPLES

[0072] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0073] Example 1 (1) Preparation of substrate 100 parts by mass (solid content equivalent, the same below) of vinyl chloride resin (manufactured by Taiyo Vinyl, product name "TH-1000", average degree of polymerization: 1000), 30 parts by mass of di(2-ethylhexyl) terephthalate (terephthalic acid ester plasticizer, manufactured by ADEKA, product name "Adeka Cizer D-810", molecular weight: 391) as a plasticizer, 2.5 parts by mass of zinc laurate (saturated fatty acid metal salt with carbon number of 12, manufactured by Nitto Kasei Kogyo, product name "Zinc Laurate") as a stabilizer, and 0.3 parts by mass of barium stabilizer as other stabilizers were kneaded using a Banbury mixer at 180°C. The kneaded product obtained was rolled with a calendar roll to obtain a sheet-like substrate with a thickness of 80 μm.

[0074] (2) Preparation of adhesive composition 19 parts by mass of 2-ethylhexyl acrylate, 75 parts by mass of vinyl acetate, 1 part by mass of acrylic acid, 5 parts by mass of methyl methacrylate, and 19 parts by mass of 2-hydroxyethyl acrylate were polymerized by solution polymerization to obtain a (meth)acrylic acid ester polymer (a polymer not curable with active energy rays). The weight average molecular weight (Mw) of this (meth)acrylic acid ester polymer was measured by the method described below and found to be 170,000.

[0075] 100 parts by mass of the above (meth)acrylic acid ester polymer, 3 parts by mass of a composition containing trimethylolpropane-modified tolylene diisocyanate (TDI-TMP) as a crosslinking agent (manufactured by Tosoh Corporation, product name "Coronate L"), 5.1 parts by mass of 2,2-dimethoxy-1,2-diphenylethan-1-one (manufactured by BASF, product name "Omnirad 651") as a photopolymerization initiator, and 63.4 parts by mass of a mixture (mixed mass ratio 1:1) of a bifunctional urethane acrylate (weight average molecular weight: 11000) and a hexafunctional urethane acrylate (weight average molecular weight: 1500) as monomers having an active energy ray curable group were mixed in toluene as a solvent to obtain a coating solution of an adhesive composition (solid concentration: 37% by mass).

[0076] (3) Formation of adhesive layer The adhesive composition coating solution obtained in step (2) above was applied to the release surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET381031") consisting of a 38 μm-thick polyethylene terephthalate film with a silicone-based release agent layer formed on one side thereof, and the resulting sheet was dried by heating to obtain a laminate consisting of a 10 μm-thick adhesive layer formed on the release sheet.

[0077] (4) Preparation of workpiece processing sheet One side of the substrate obtained in the above step (1) was subjected to a corona treatment. Then, the corona-treated side of the substrate was bonded to the adhesive layer side of the laminate obtained in the above step (3) to obtain a workpiece processing sheet.

[0078] (5) Measurement method and calculation method of weight average molecular weight The weight average molecular weight (Mw) mentioned above is a weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement) and converted into standard polystyrene. <Measurement conditions> Measuring device: Tosoh HLC-8320 GPC columns (passed in the following order): Tosoh Corporation TSK gel superH-H TSK gel superHM-H TSK gel superH2000 Measurement solvent: Tetrahydrofuran ·Measurement temperature: 40℃

[0079] [Examples 2-3, Comparative Examples 1-3] A workpiece processing sheet was obtained in the same manner as in Example 1, except that the types and contents of the plasticizer and stabilizer used in preparing the substrate were changed as shown in Table 1.

[0080] [Test Example 1] (TOF-SIMS evaluation of substrate) For the substrates produced in the examples and comparative examples, mass spectra were obtained by time-of-flight secondary ion mass spectrometry (TOF-SIMS) to confirm the types of fatty acid metal salts contained therein.

[0081] Specifically, the measurement device used was an ION-TOF product called "TOF.SIMS5," and the primary ions were Bi3 ++ The analysis was performed using a spectrophotometer with a primary ion accelerating voltage of 30 kV, a raster size of 300 μm, and positive and negative secondary ion polarities. It was confirmed whether any of the peaks of a saturated fatty acid metal salt with 16 carbon atoms, a saturated fatty acid metal salt with 18 carbon atoms, an unsaturated fatty acid metal salt with 16 carbon atoms, or an unsaturated fatty acid metal salt with 18 carbon atoms were detected from the obtained mass spectrum. The results are shown in Table 2.

[0082] [Test Example 2] (Evaluation of Cutting Chip Suppression) After peeling off the release sheet from the workpiece processing sheet produced in the examples and comparative examples, the exposed surface of the exposed adhesive layer was attached to one side of an 8-inch silicon wafer using a tape mounter (manufactured by Lintec Corporation, product name "RAD2500m / 12"). Next, a dicing ring frame was attached to the periphery of the exposed surface of the workpiece processing sheet (at a position that does not overlap with the silicon wafer). Furthermore, the workpiece processing sheet was cut to fit the outer diameter of the ring frame.

[0083] Thereafter, the silicon wafer was diced into individual chips having a size of 1 mm×1.0 mm by dicing under the following dicing conditions using a dicing device (manufactured by Disco Corporation, product name “DFD6362”). Dicing Conditions Wafer thickness: 350μm Dicing equipment: Disco, product name "DFD-6362" Blade: Disco, product name "ZH05-SD2000-N1-90CC" Blade rotation speed: 30,000 rpm Cutting speed: 100mm / sec Blade height: 0.060mm Cutting water amount: 1.0L / min Cutting water temperature: 20℃

[0084] After dicing, the substrate side of the workpiece processing sheet was irradiated with ultraviolet light (UV) (illuminance: 230 mW / cm) using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000m12"). 2 ,Light amount: 190mJ / cm 2 ) to cure the adhesive layer.

[0085] Next, using a pickup device, the workpiece processing sheet was expanded at room temperature to an expansion amount of 3 mm, while the chip was pushed up using a needle at a push-up height of 300 μm and a push-up speed of 20 mm / sec. At the same time as the push-up, the chip was separated from the workpiece processing sheet using a collet with a size of 10 mm x 10 mm. These operations were repeated 10 times, and the surface of the separated 10 chips to which the workpiece processing sheet was attached was visually confirmed to have no adhesive attached thereto, and the adhesive residue was evaluated according to the following criteria. The results are shown in Table 2. ◯: No adhesive was attached to any of the 10 chips. ×: Adhesive was found to be attached to at least one chip.

[0086] The details of the compounds listed in Table 1 are as follows. [Plasticizer] Di(2-ethylhexyl) terephthalate: ADEKA Corporation, product name "ADEKA Cizer D-810", molecular weight: 391 Adipic acid polyester: ADEKA Corporation, product name "ADEKA Cizer PN-7160", average molecular weight: 800, plasticization efficiency value: 1.00 Isononyl adipate: New Japan Chemical Co., Ltd., product name: Sanso Cizer DINA, molecular weight: 398 [Stabilizer] Zinc laurate: Metal salt of saturated fatty acid with 12 carbon atoms, manufactured by Nitto Kasei Kogyo Co., Ltd., product name "Zinc laurate" Zinc oleate: Metal salt of unsaturated fatty acid with 18 carbon atoms, manufactured by Mitsuwa Chemical Co., Ltd., product name "Zinc oleate" Zinc palmitate: Metal salt of saturated fatty acid with 16 carbon atoms, manufactured by Mitsuwa Chemical Co., Ltd., product name "Zinc palmitate" Zinc stearate: Metal salt of saturated fatty acid with 18 carbon atoms, manufactured by Fujifilm Wako Pure Chemical Industries, product name "Zinc stearate" Zinc behenate: Metal salt of saturated fatty acid with 22 carbon atoms, manufactured by Nitto Kasei Kogyo Co., Ltd., product name "Zinc behenate"

[0087] [Table 1]

[0088] [Table 2]

[0089] As is clear from Table 2, the workpiece processing sheets produced in the examples were able to effectively suppress the occurrence of adhesive residue. [Industrial Applicability]

[0090] The workpiece processing sheet of the present invention can be suitably used for processing workpieces such as semiconductor wafers.

Claims

1. A workpiece processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate, The pressure-sensitive adhesive layer is made of an active energy ray-curable pressure-sensitive adhesive, and the adhesive strength of the pressure-sensitive adhesive sheet to the workpiece is reduced by irradiation with active energy rays, the substrate is provided with a resin layer formed from a resin composition containing a vinyl chloride resin and a stabilizer, The stabilizer contains at least one of a saturated fatty acid metal salt having 12 or more and less than 18 carbon atoms and an unsaturated fatty acid metal salt having 12 or more and less than 20 carbon atoms. A work processing sheet characterized by:

2. The workpiece processing sheet according to claim 1, characterized in that the content of the stabilizer in the resin composition is 0.01 parts by mass or more and 8 parts by mass or less per 100 parts by mass of the vinyl chloride resin.

3. 3. The workpiece processing sheet according to claim 1, wherein the resin composition contains a plasticizer.

4. The workpiece processing sheet according to any one of claims 1 to 3, characterized in that the base material is made of a single layer of the resin layer.

5. 4. The workpiece processing sheet according to claim 1, wherein the base material is made up of a plurality of layers, at least one of which is the resin layer.

6. The workpiece processing sheet according to any one of claims 1 to 5, characterized in that it is a dicing sheet.

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