Workpiece processing sheet, workpiece processing method, and use of workpiece processing sheet

Abstract

To provide a workpiece processing sheet excellent in expandability and low friction.SOLUTION: A workpiece processing sheet 1 includes a substrate 11, and an adhesive layer 12 laminated on one surface side of the substrate 11. In the workpiece processing sheet 1, a fluorine atomic ratio measured by X-ray photoelectron spectroscopy (XPS) in a surface on the opposite side to the adhesive layer 12 of the substrate 11 is 0.01 atm% or more and 2.5 atm% or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a workpiece processing sheet used for processing a workpiece such as a semiconductor wafer, a workpiece processing method, and use of the workpiece processing sheet. [Background technology]

[0002] Semiconductor wafers such as silicon and gallium arsenide and various packages are manufactured in large diameters, cut into chips (diced), peeled off (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 then undergo processing such as backgrinding, dicing, cleaning, drying, expanding, picking up, and mounting.

[0003] In the above-mentioned pickup process, in order to facilitate the pickup of chips, the chips may be pushed up individually from the side of the workpiece processing sheet opposite to the side on which the chips are stacked. In particular, to prevent collisions between chips during pickup and to facilitate pickup, the workpiece processing sheet is usually stretched (expanded) to separate the chips. Therefore, the workpiece processing sheet is required to have excellent flexibility to enable good expansion.

[0004] Patent Document 1 discloses a dicing substrate film that includes a base layer and a surface layer, with the aim of providing a workpiece processing sheet with excellent expandability, and the surface layer contains a specified polystyrene resin and a specified vinyl aromatic hydrocarbon-conjugated diene hydrocarbon copolymer or a hydrogenated product thereof. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6146616 Summary of the Invention [Problem to be solved by the invention]

[0006] Generally, workpiece processing sheets are manufactured in a long shape and wound around a core to form a roll. When winding the workpiece processing sheet onto such a roll or when unwinding the workpiece processing sheet from the roll, the workpiece processing sheet is transported using multiple guide rolls. In this case, the workpiece processing sheet may stick to the guide rolls, preventing smooth transport, or may become wrinkled or loose due to such sticking.

[0007] Furthermore, when using a workpiece processing sheet, the workpiece processing sheet may stick to a tape mounter or the like, making it impossible to perform the desired operation.

[0008] Therefore, workpiece processing sheets are also required to have low friction so as to prevent them from sticking to such guide rolls, tape mounters, etc.

[0009] The present invention has been made in view of the above circumstances, and has an object to provide a workpiece processing sheet that has excellent expandability and low friction. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, first, the present invention provides a workpiece processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate, characterized in that the fluorine atomic ratio measured by X-ray photoelectron spectroscopy (XPS) on the side of the substrate opposite the adhesive layer is 0.01 atm% or more and 2.5 atm% or less (Invention 1).

[0011] The workpiece processing sheet according to the above invention (Invention 1) has a substrate exhibiting the above-mentioned fluorine atomic ratio, and therefore achieves excellent expandability while exhibiting excellent low friction properties that can suppress sticking to guide rolls, tape mounters, etc.

[0012] In the above invention (invention 1), the fluorine atomic ratio is preferably 0.35 atm % or more (invention 2).

[0013] In the above inventions (Inventions 1 and 2), the substrate preferably contains at least one of polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), perfluoroalkoxyalkane (PFA), perfluoroethylene propene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), and ethylene chlorotrifluoroethylene copolymer (ECTFE) (Invention 3).

[0014] In the above inventions (Inventions 1 to 3), the substrate preferably contains at least one resin selected from thermoplastic polyurethane and ethylene-(meth)acrylic acid copolymer as a main component (Invention 4).

[0015] In the above inventions (Inventions 1 to 4), the static friction force measured between the substrate side surface of the workpiece processing sheet and the aluminum plate in accordance with JIS K7125:1999 at a load of 1.96 N and a tensile speed of 100 mm / min is: 0.001 N or more, 4.0 It is preferable that the number of the particles is N or less (Invention 5).

[0016] In the above inventions (Inventions 1 to 5), the substrate preferably has a breaking elongation of 400% or more and 1000% or less in a tensile test carried out at 23° C. (Invention 6).

[0017] In the above inventions (Inventions 1 to 6), the base material has a breaking strength in a tensile test carried out at 23°C. 20 N / 15mm or more, 90It is preferable that the resistance be N / 15 mm or less (Invention 7).

[0018] Secondly, the present invention provides a workpiece processing method (Invention 8), characterized by comprising a stacking step of stacking multiple workpieces on the adhesive layer side of the workpiece processing sheet (Inventions 1 to 7), and an expanding step of stretching the workpiece processing sheet on which the multiple workpieces are stacked, thereby separating the multiple workpieces from each other.

[0019] Thirdly, the present invention provides a use of the workpiece processing sheet (Inventions 1 to 7) for a workpiece processing method, characterized in that the workpiece processing method comprises a stacking step of stacking multiple workpieces on the adhesive layer side of the workpiece processing sheet, and an expanding step of stretching the workpiece processing sheet on which the multiple workpieces are stacked, thereby separating the multiple workpieces from each other (Invention 9). [Effects of the Invention]

[0020] The workpiece processing sheet according to the present invention has excellent expandability and low friction. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view of a workpiece processing sheet according to one embodiment of the present invention. [Figure 2] FIG. 1 is a diagram for explaining a test for evaluating low friction properties. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present invention will be described. A cross-sectional view of a workpiece processing sheet according to one embodiment is shown in Fig. 1. The workpiece processing sheet 1 shown in Fig. 1 includes a substrate 11 and an adhesive layer 12 laminated on one side of the substrate 11.

[0023] In the workpiece processing sheet 1 according to this embodiment, the fluorine atom ratio measured by X-ray photoelectron spectroscopy (XPS) on the surface of the substrate 11 opposite the adhesive layer 12 is 0.01 atm% or more and 2.5 atm% or less.

[0024] The workpiece processing sheet 1 according to this embodiment has excellent low friction because the fluorine atomic ratio is 0.01 atm% or more. That is, the frictional force generated between the substrate 11 side of the workpiece processing sheet 1 and a guide roll, tape mounter, or the like is effectively reduced, making it less likely to stick to the guide roll, tape mounter, or the like. As a result, the workpiece processing sheet 1 according to this embodiment can be easily transported and used, and the occurrence of wrinkles and sagging in the workpiece processing sheet 1 due to sticking can be effectively suppressed. To facilitate achieving even better low friction, the fluorine atomic ratio is preferably 0.35 atm% or more, and more preferably 1.0 atm% or more.

[0025] Furthermore, the workpiece processing sheet 1 according to this embodiment exhibits excellent expandability due to the fluorine atomic ratio of 2.5 atm% or less. Generally, adding a specific additive to the substrate 11 to impart desired performance can impair the flexibility of the substrate 11 and reduce its expandability. As described below, the workpiece processing sheet 1 according to this embodiment can achieve a fluorine atomic ratio of 0.01 atm% or more by adding a specific component to the substrate. However, by keeping the fluorine atomic ratio at 2.5 atm% or less, it is possible to achieve both the excellent low friction and excellent expandability described above. To more easily achieve both excellent low friction and excellent expandability, the fluorine atomic ratio is preferably 2.3 atm% or less, and more preferably 1.8 atm% or less.

[0026] The details of the method for measuring the fluorine atom ratio are as described in the test examples below.

[0027] 1. Composition of workpiece processing sheet (1) Base material The structure and composition of the substrate 11 in this embodiment are not particularly limited as long as it exhibits the above-mentioned fluorine atomic ratio. A suitable example of the composition of the substrate 11 is one in which a predetermined amount of a fluorine-containing compound is added to a resin as the main component.

[0028] (1-1) Resin as the main component Although examples of the resin as the main component mentioned above are not particularly limited, it is preferable to use at least one resin selected from thermoplastic polyurethane and ethylene-(meth)acrylic acid copolymer. Substrates made of these resins generally tend to have high frictional forces with guide rolls, etc. Therefore, substrates made of these resins can effectively enjoy the benefits of the low friction achieved by the work processing sheet 1 according to this embodiment. Note that, in this specification, "(meth)acrylic acid" refers to both acrylic acid and methacrylic acid. The same applies to other similar terms. Furthermore, "copolymer" also includes the concept of a "polymer" made of a single monomer.

[0029] The thermoplastic polyurethane is not particularly limited, and may be, for example, a resin obtained by reacting an isocyanate with a polyol. Examples of the diisocyanate include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and hexamethylene diisocyanate. Examples of the polyol include polyester polyols such as lactone-based polyester polyols and adipate-based polyester polyols; polyether polyols such as polypropylene (ethylene) polyols and polytetramethylene ether glycol; and polycarbonate polyols.

[0030] As the thermoplastic polyurethane according to this embodiment, it is preferable to use an ether-type thermoplastic polyurethane obtained by using a polyol containing an ether bond. By using such an ether-type thermoplastic polyurethane, it becomes easier to achieve both low friction and expandability.

[0031] Examples of the ethylene-(meth)acrylic acid copolymer include an ethylene-acrylic acid copolymer and an ethylene-methacrylic acid copolymer, and among these, an ethylene-methacrylic acid copolymer is preferred.

[0032] Resins other than those mentioned above can also be used as the main component constituting the substrate 11. For example, polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; ethylene-vinyl acetate copolymers; ethylene-methyl (meth)acrylate copolymers, and other ethylene-(meth)acrylic acid ester copolymers; polyolefin-based resins such as polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-norbornene copolymers, and norbornene resins; polyvinyl chloride-based resins such as polyvinyl chloride and vinyl chloride copolymers; (meth)acrylic acid ester copolymers; polyimide; polystyrene; polycarbonate; fluororesins, etc. may be used.

[0033] The above resins may be used alone or in combination of two or more.

[0034] In this specification, the term "main component" in relation to the substrate refers to a component that accounts for more than 50% by mass of all components constituting the substrate, particularly a component that accounts for 60% by mass or more, and further a component that accounts for 70% by mass or more.

[0035] (1-2) Fluorine-containing compounds Although examples of the fluorine-containing compound are not particularly limited, it is preferable to use at least one of polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), perfluoroalkoxyalkane (PFA), perfluoroethylene propene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), and ethylene chlorotrifluoroethylene copolymer (ECTFE). By using these compounds, it becomes easier to achieve both excellent low friction and excellent expandability.

[0036] The polytetrafluoroethylene may be, for example, in powder form. In this case, the base material 11 can be produced using a mixture obtained by adding powdered polytetrafluoroethylene to a resin that is the main component. Note that the polytetrafluoroethylene may remain in powder form in the base material 11 thus obtained.

[0037] The polytetrafluoroethylene preferably has a number average molecular weight of 10,000 or more, particularly preferably 100,000 or more, and even more preferably 1,000,000 or more. The number average molecular weight is preferably 10,000,000 or less, particularly preferably 7,000,000 or less, and even more preferably 5,000,000 or less. By using polytetrafluoroethylene having a number average molecular weight within the above range, it becomes easier to achieve both excellent low friction and excellent expandability.

[0038] The content of polytetrafluoroethylene in the substrate 11 is preferably 0.001% by mass or more, particularly preferably 0.03% by mass or more, and even more preferably 0.1% by mass or more. Furthermore, the content is preferably 80% by mass or less, particularly preferably 60% by mass or less, and even more preferably 50% by mass or less. By including polytetrafluoroethylene in the substrate 11 within this range, it becomes easier to achieve the aforementioned fluorine atom ratio.

[0039] (1-3) Other Compositions and Ingredients The base material 11 may be made of a resin whose main component contains fluorine atoms. That is, the base material 11 may be made of a resin obtained by introducing functional groups containing fluorine atoms into the above-mentioned main component resin. In this case, the base material 11 does not need to contain a compound containing fluorine.

[0040] The substrate 11 may also contain components other than those described above. Examples of such components include various additives such as flame retardants, plasticizers, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion scavengers. The content of these additives is not particularly limited, but is preferably within a range that allows the substrate to exhibit the desired functions.

[0041] (1-4) Surface treatment of substrate The surface of the substrate 11 on which the pressure-sensitive adhesive layer 12 is laminated may be subjected to surface treatment such as primer treatment, corona treatment, plasma treatment, roughening treatment (matt finish), etc. in order to improve adhesion to the pressure-sensitive adhesive layer 12. Examples of roughening treatment include embossing and sandblasting.

[0042] (1-5) Manufacturing method of substrate The method for producing the substrate 11 in this embodiment is not particularly limited, and examples thereof include melt extrusion methods such as inflation, T-die, and round die methods; calendaring methods; and solution methods such as dry and wet methods. Among these, from the viewpoint of efficiently producing the substrate, it is preferable to employ the melt extrusion method, and it is particularly preferable to employ the inflation method.

[0043] When the above-mentioned fluorine-containing compound is used as the material of the substrate 11, the compound may be melt-kneaded with the resin as the main component, and then extruded using a known extruder to form a film.

[0044] (1-6) Physical properties of the substrate The base material 11 in this embodiment preferably has a breaking elongation of 400% or more, particularly preferably 450% or more, and even more preferably 520% ​​or more, in a tensile test carried out at 23°C. The base material 11 according to this embodiment is easily able to achieve such a relatively high breaking elongation when the fluorine atom ratio is within the aforementioned range. Furthermore, a breaking elongation of 500% or more makes it easy to exhibit excellent expandability. The upper limit of the breaking elongation is not particularly limited, and may be, for example, 1000% or less, particularly 950% or less, or even 900% or less. Details of the method for measuring the breaking elongation are as described in the test examples below.

[0045] Furthermore, the base material 11 in this embodiment preferably has a breaking strength of 90 N / 15 mm or less, particularly 85 N / 15 mm or less, as determined by a tensile test at 23°C. By ensuring that the fluorine atom ratio is within the aforementioned range, the base material 11 according to this embodiment can maintain the strength (stress) at break within this range. Furthermore, by ensuring that the breaking strength is 90 N / 15 mm or less, excellent expandability is readily exhibited. The lower limit of the breaking strength is not particularly limited, and may be, for example, 20 N / 15 mm or more, particularly 40 N / 15 mm or more, or even 60 N / 15 mm or more. Details of the method for measuring the breaking strength are as described in the test examples below.

[0046] In this embodiment, the thickness of the substrate 11 is preferably 50 μm or more, particularly preferably 60 μm or more, and even more preferably 80 μm or more. When the thickness of the substrate 11 is 50 μm or more, the workpiece processing sheet 1 according to this embodiment has excellent handleability. Furthermore, the thickness of the substrate 11 is preferably 200 μm or less, particularly preferably 180 μm or less, and even more preferably 150 μm or less. When the thickness of the substrate 11 is 200 μm or less, it becomes easier to achieve excellent expandability.

[0047] (2) Adhesive layer The adhesive constituting the adhesive layer 12 in this embodiment is not particularly limited as long as it can exert sufficient adhesive strength to the adherend (particularly, adhesive strength to the workpiece sufficient for processing the workpiece). Examples of adhesives constituting the adhesive layer 12 include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, polyvinyl ether adhesives, etc. Among these, it is preferable to use acrylic adhesives because they can easily exert the desired adhesive strength.

[0048] The adhesive constituting the adhesive layer 12 in this embodiment may be an adhesive that is not active energy ray curable, or may be an adhesive that is active energy ray curable (hereinafter, may be referred to as an "active energy ray curable adhesive"). When the adhesive layer 12 is composed of an active energy ray curable adhesive, the adhesive layer 12 can be cured by irradiation with active energy rays, and the adhesive strength of the workpiece processing sheet 1 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 1.

[0049] As the pressure-sensitive adhesive not having active energy ray curability and the active energy ray curable pressure-sensitive adhesive, known pressure-sensitive adhesives can be used.

[0050] In this embodiment, the thickness of the adhesive layer 12 is preferably 1 μm or more, particularly preferably 3 μm or more, and even more preferably 5 μm or more. Furthermore, the thickness of the adhesive layer 12 is preferably 70 μm or less, particularly preferably 30 μm or less, and even more preferably 15 μm or less. By keeping the thickness of the adhesive layer 12 within the above-mentioned range, the workpiece processing sheet 1 according to this embodiment can easily exhibit the desired adhesiveness.

[0051] (3) Release sheet In the workpiece processing sheet 1 of this embodiment, a release sheet may be laminated on the side of the adhesive layer 12 opposite the substrate 11 (hereinafter sometimes referred to as the "adhesive side") in order to protect that side until it is attached to the workpiece.

[0052] The release sheet may have any configuration, 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 such plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. Silicone-based, fluorine-based, and long-chain alkyl-based release agents can be used, and among these, silicone-based ones are preferred because they are inexpensive and provide stable performance.

[0053] There are no particular limitations on the thickness of the release sheet, and it may be, for example, 16 μm or more and 250 μm or less.

[0054] (4) Other In the workpiece processing sheet 1 according to this embodiment, an adhesive layer may be laminated on the surface of the adhesive layer 12 opposite the substrate 11. In this case, the workpiece processing sheet 1 according to this embodiment can be used as a dicing / die bonding sheet. A workpiece is attached to the surface of the adhesive layer opposite the adhesive layer 12, and the adhesive layer is diced together with the workpiece to obtain a chip on which the individual adhesive layers are laminated. The individual adhesive layers allow the chip to be easily fixed to the object on which it is to be mounted. The material constituting the adhesive layer described above is preferably a material containing a thermoplastic resin and a low-molecular-weight thermosetting adhesive component, or a material containing a B-stage (semi-cured) thermosetting adhesive component.

[0055] Furthermore, in the workpiece processing sheet 1 according to this embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer 12. In this case, the workpiece processing sheet 1 according to this embodiment can be used as a sheet for both protective film formation and dicing. With such a sheet, a workpiece is attached to the surface of the protective film forming layer opposite the adhesive layer 12, and the protective film forming layer is diced together with the workpiece to obtain a chip on which a singulated protective film forming layer is laminated. The workpiece preferably has a circuit formed on one side. In this case, the protective film forming layer is typically laminated on the side opposite the side on which the circuit is formed. The singulated protective film forming layer can be cured at a predetermined time to form a protective film with sufficient durability on the chip. The protective film forming layer is preferably made of an uncured curable adhesive.

[0056] 2. Physical properties of workpiece processing sheets In the workpiece processing sheet 1 according to this embodiment, the static friction force between the surface of the substrate 11 and the aluminum plate, measured in accordance with JIS K7125:1999 at a load of 1.96 N and a tensile speed of 100 mm / min, is preferably 4.0 N or less, more preferably 3.5 N or less, and even more preferably 3.0 N or less. The substrate 11 according to this embodiment, having a fluorine atom ratio within the aforementioned range, easily achieves such a relatively low static friction force. Furthermore, a static friction force of 4.0 N or less easily exhibits excellent low friction properties. The lower limit of the static friction force is not particularly limited and may be, for example, 0.001 N or more, particularly 0.005 N or more, or even 0.01 N or more. Details of the method for measuring the static friction force are as described in the test examples below.

[0057] 3. Manufacturing method of workpiece processing sheet There are no particular limitations on the method for producing the workpiece processing sheet 1 according to this embodiment. For example, it is preferable to obtain the workpiece processing sheet 1 by forming an adhesive layer 12 on a release sheet, and then laminating one side of the substrate 11 on the surface of the adhesive layer 12 opposite the release sheet.

[0058] The pressure-sensitive adhesive layer 12 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 12 and, if desired, a solvent or dispersion medium is prepared. The coating liquid is then applied to the releasable surface of a release sheet (hereinafter sometimes referred to as the "release surface"). The resulting coating film is then dried to form the pressure-sensitive adhesive layer 12.

[0059] The coating liquid can be applied by a known method, such as bar coating, knife coating, roll coating, blade coating, die coating, or gravure coating. The properties of the coating liquid are not particularly limited as long as it allows application, and the liquid may contain components for forming the pressure-sensitive adhesive layer 12 as a solute or as a dispersoid. The release sheet may be peeled off as a processing material, or may protect the pressure-sensitive adhesive layer 12 until it is attached to the adherend.

[0060] When the adhesive composition for forming the adhesive layer 12 contains the above-mentioned crosslinking agent, it is preferable to change the above-mentioned drying conditions (temperature, time, etc.) or to separately perform a heat treatment to promote the crosslinking reaction between the polymer component in the coating film and the crosslinking agent, thereby forming a crosslinked structure with a desired density in the adhesive layer 12. Furthermore, in order to promote the above-mentioned crosslinking reaction sufficiently, after the adhesive layer 12 and the substrate 11 are bonded together, curing may be performed, for example, by leaving the adhesive layer 12 to stand in an environment of 23°C and a relative humidity of 50% for several days.

[0061] 4. How to use the workpiece processing sheet The workpiece processing sheet 1 according to this embodiment can be used for processing workpieces such as semiconductor wafers. That is, after the adhesive surface of the workpiece processing sheet 1 according to this embodiment is attached to the workpiece, the workpiece can be processed on the workpiece processing sheet 1. Depending on the processing, the workpiece processing sheet 1 according to this embodiment can be used as a transfer sheet, back-grinding sheet, dicing sheet, expanding sheet, pickup sheet, etc. Examples of workpieces include semiconductor components such as semiconductor wafers and semiconductor packages, and glass components such as glass plates.

[0062] As described above, the workpiece processing sheet 1 according to this embodiment has an excellent low-friction surface on the substrate side, which effectively prevents sticking to guide rolls, tape mounters, etc., and the resulting problems. From this perspective, the workpiece processing sheet 1 according to this embodiment is suitable for use as a sheet transported by guide rolls or handled using a tape mounter. More specifically, it is suitable for use as a transfer sheet, backgrinding sheet, dicing sheet, expanding sheet, or pickup sheet.

[0063] Furthermore, as described above, the workpiece processing sheet 1 according to this embodiment also exhibits excellent expandability. From this viewpoint, the workpiece processing sheet 1 according to this embodiment is suitable for use as a sheet on which expansion is performed, specifically, as a dicing sheet, an expanding sheet, or a pick-up sheet.

[0064] More specifically, the workpiece processing sheet 1 according to this embodiment is suitable for use in a workpiece processing method or a semiconductor device manufacturing method that includes a lamination step of laminating multiple workpieces on the surface of the workpiece processing sheet facing the adhesive layer 12, and an expansion step of stretching the workpiece processing sheet on which the multiple workpieces are stacked to separate the multiple workpieces from one another. These methods may further include a pick-up step of individually picking up the multiple workpieces in a separated state after the expansion step.

[0065] In the above-described method, the plurality of workpieces are preferably chips obtained by dividing the semiconductor member, glass member, or the like. In this case, a plurality of chips obtained by dividing in advance may be stacked on the workpiece processing sheet 1 according to this embodiment. Alternatively, a plurality of chips may be obtained by dividing the semiconductor member, glass member, or the like on the workpiece processing sheet 1 according to this embodiment. In the latter case, in the above-described method, instead of the above-described stacking step, a dicing step may be performed to divide the workpieces on the surface of the adhesive layer 12 opposite the substrate 11.

[0066] The above-mentioned laminating step, dicing step, expanding step and pick-up step can each be carried out using a conventional method.

[0067] When the workpiece processing sheet 1 according to this embodiment has the adhesive layer described above, the workpiece processing sheet 1 can be used as a dicing / die bonding sheet. Furthermore, when the workpiece processing sheet 1 according to this embodiment has the protective film forming layer described above, the workpiece processing sheet 1 can be used as a protective film forming / dicing sheet.

[0068] Furthermore, when the adhesive layer 12 in the workpiece processing sheet 1 according to this embodiment is composed of the aforementioned active energy ray-curable adhesive, it is also preferable to irradiate the adhesive layer 12 with active energy rays during use. That is, when processing of a workpiece on the workpiece processing sheet 1 is completed and the processed workpiece is to be separated from the workpiece processing sheet 1, it is preferable to irradiate the adhesive layer 12 with active energy rays before the separation. This hardens the adhesive layer 12, effectively reducing the adhesive strength of the adhesive sheet to the processed workpiece, and facilitating separation of the processed workpiece.

[0069] The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0070] For example, other layers may be laminated between the substrate 11 and the adhesive layer 12 in the workpiece processing sheet 1 of this embodiment, or on the side of the substrate 11 opposite the adhesive layer 12. [Example]

[0071] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0072] Example 1 (1) Preparation of the substrate An ether-based thermoplastic polyurethane (Shore A hardness (measured according to JIS K 6253): 95, density: 1.12 g / cm) was placed in a single-layer inflation film-making device equipped with an extruder with a 100 mm diameter. 3 A mixture of polytetrafluoroethylene (PTFE) powder (manufactured by MC Yamasan Polymers Co., Ltd., product name "Ace Flon") added to the mixture was supplied.

[0073] The mixture was then melt-kneaded and extruded through a single-layer die at a temperature of 205°C to form a substrate film having a thickness of 100 µm, containing thermoplastic polyurethane as the main component.

[0074] The fluorine atomic ratio on one side of the substrate (the side opposite to the side on which the adhesive layer is to be laminated) was measured as described in Test Example 1 below and was found to be 0.37 atm%. The arithmetic mean roughness Ra of both sides of the substrate was measured (three times and the average value calculated) using a contact roughness meter (manufactured by Mitutoyo Corporation, product name "SV-3000") and found to be 0.32 μm on one side (the side opposite to the side on which the adhesive layer is to be laminated) and 0.25 μm on the other side (the side on which the adhesive layer is to be laminated).

[0075] (2) Preparation of adhesive composition 80 parts by mass of 2-ethylhexyl acrylate (2EHA), 10 parts by mass of methyl methacrylate (MMA), and 10 parts by mass of 2-hydroxyethyl acrylate (HEA) were polymerized by solution polymerization to obtain a (meth)acrylic acid ester polymer. The weight average molecular weight (Mw) of the polymer was measured by the method described below and was found to be 580,000.

[0076] 100 parts by mass (solid content equivalent, same below) of the obtained (meth)acrylic acid ester polymer and 5 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Toyo Ink Co., Ltd., product name "BHS-8518") as a crosslinking agent were mixed in a solvent to obtain a coating liquid of an adhesive composition.

[0077] (3) Formation of adhesive layer The adhesive composition coating solution obtained in step (2) was applied to the release surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET381031"), which was a 38 μm-thick polyethylene terephthalate (PET) film with a silicone-based release agent layer formed on one side thereof, and the coating was dried by heating to form an adhesive layer with a thickness of 10 μm on the release sheet. This resulted in a laminate consisting of the release sheet and the adhesive layer.

[0078] (4) Preparation of workpiece processing sheet A workpiece processing sheet was obtained by bonding one side (the side opposite to the side on which the fluorine atom ratio was measured) of the substrate obtained in the above step (1) to the side of the adhesive layer of the laminate obtained in the above step (3).

[0079] Here, the weight average molecular weight (Mw) is a weight average molecular weight measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement) and converted into standard polystyrene. <Measurement conditions> Measurement equipment: Tosoh HLC-8320 GPC columns (passed in the following order): Tosoh Corporation TSK gel superH-H TSK gel super HM-H TSK gel superH2000 Measurement solvent: tetrahydrofuran ·Measurement temperature: 40℃

[0080] [Examples 2 to 4 and Comparative Example 2] A workpiece processing sheet was obtained in the same manner as in Example 1, except that the amount of PTFE powder added was changed so that the fluorine atom ratio of the substrate would be the value shown in Table 1.

[0081] Comparative Example 1 An ether-based thermoplastic polyurethane (Shore A hardness (measured according to JIS K 6253): 95, density: 1.12 g / cm) was placed in a single-layer inflation film-making device equipped with an extruder with a 100 mm diameter. 3 ) was supplied. After the resin was melt-kneaded, it was introduced into a single-layer die at a temperature of 205 ° C and extruded to form a substrate having a thickness of 100 μm containing thermoplastic polyurethane as a main component. A workpiece processing sheet was obtained in the same manner as in Example 1, except that the substrate thus obtained was used.

[0082] The fluorine atom ratio on one side of the obtained substrate (the side opposite to the side on which the pressure-sensitive adhesive layer was laminated) was measured as described in Test Example 1 below, and was found to be 0.00 atm %.

[0083] [Test Example 1] (Measurement of Fluorine Atom Ratio) The workpiece processing sheets manufactured in the examples and comparative examples were cut into 5 mm x 5 mm pieces to obtain samples for measurement. Then, elemental analysis was performed on the substrate side of the samples using an X-ray photoelectron spectroscopy (XPS) device (ULVAC, product name "PHI Quantera SXM"). Specifically, C1s, N1s, O1s, and F1s were measured, and the ratio of detected F1s was calculated as the fluorine atomic ratio (atm%). Measurements were performed twice for each sample, and the average value was calculated. The results are shown in Table 1.

[0084] [Test Example 2] (Measurement of static friction force) The static friction force (N) against an aluminum plate was measured for the substrate side of the workpiece processing sheets manufactured in the examples and comparative examples in accordance with JIS K7125:1999 at a load of 1.96 N and a pulling speed of 100 mm / min. Measurements were performed three times for each sample, and the average value was calculated. The results are shown in Table 1.

[0085] [Test Example 3] (Measurement of breaking elongation and breaking strength) The substrates used in the Examples and Comparative Examples were cut to a size of 15 mm wide x 150 mm long to obtain samples for measurement. The samples were placed in a universal tensile tester (Shimadzu Corporation, product name "AG-IS") so that the stretchable portion was 100 mm. The samples were then stretched at 23°C and a tensile speed of 200 mm / min. The elongation and stress (strength) at which the sample broke were defined as the breaking elongation (%) and breaking strength (N / 15 mm), respectively. Measurements were performed three times for each sample in the extrusion direction (MD) during substrate preparation and in the direction perpendicular to it (CD), and the average of these six measurements was calculated. The results are shown in Table 1.

[0086] [Test Example 4] (Evaluation of low friction) The workpiece processing sheets produced in the examples and comparative examples were manufactured into long strips measuring 20 m in length and 30 cm in width. They were transported using four guide rolls, and the low friction of the workpiece processing sheets was evaluated by checking for any transport problems during transport.

[0087] Specifically, as shown in Figure 2, workpiece processing sheet 1 was unwound from workpiece processing sheet roll 2, passed through guide rolls 3a, 3b, 3c, and 3d in this order, and wound onto winding core 30. Here, the roll 2 used was one in which the substrate side of workpiece processing sheet 1 was wound on the outside. Therefore, during transport, the substrate side of workpiece processing sheet 1 came into contact with guide rolls 3b and 3d. The unwinding speed was 2 m / min.

[0088] Each of the four guide rolls was made of metal and had a diameter of 20 cm and a width of 60 cm. The distance between adjacent guide rolls was 40 cm. The winding core 4 was made of ABS and had a diameter of 3 inches.

[0089] The low friction was evaluated based on the following criteria, and the results are shown in Table 1. ◯: The surface on the substrate side did not stick to the guide roll, and all 20 m could be wound onto the winding core 4 satisfactorily. △: Although wrinkles and slack occurred in the workpiece processing sheet 1 when it was wound onto the winding core 4, all 20 m could be wound onto the winding core 4 satisfactorily. ×: At least one of the following three problems occurred: the substrate side surface stuck to the guide roll, wrinkles or slack occurred in the work processing sheet 1 when it was wound onto the winding core 4, and the work processing sheet 1 was wrapped around the guide roll, and good winding onto the winding core 4 was not possible.

[0090] [Test Example 5] (Evaluation of expandability) The release sheet was peeled off from the workpiece processing sheets produced in the Examples and Comparative Examples, and the exposed surface of the adhesive layer was attached to a 6-inch ring frame. The workpiece processing sheet was cut to fit the outer diameter of the ring frame and then placed in an expansion tester (manufactured by JCM Corporation, product name "ME-300B"). The ring frame was then pulled down at a pull-down distance of 50 mm and a pull-down speed of 5 mm / s to expand the workpiece processing sheet. Based on the condition of the workpiece processing sheet at that time, the expandability was evaluated according to the following criteria. The results are shown in Table 1. ⊚: The workpiece processing sheet was able to expand without breaking or whitening due to yielding. ◯: The workpiece processing sheet was able to expand without breaking. ×: The workpiece processing sheet broke or whitened due to yielding, and expansion was not possible.

[0091] [Table 1]

[0092] As is clear from Table 1, the workpiece processing sheets produced in the examples exhibited excellent low friction, and while allowing for good transport, they also exhibited excellent expandability. [Industrial Applicability]

[0093] The workpiece processing sheet of the present invention can be suitably used for processing workpieces such as semiconductor wafers. [Explanation of symbols]

[0094] 1...Work processing sheet 11...Base material 12...Adhesive layer 2: Roll body 3a, 3b, 3c, 3d: Guide roll 4: Winding core

Claims

1. A workpiece processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate, the substrate contains at least one resin selected from thermoplastic polyurethane and ethylene-(meth)acrylic acid copolymer as a main component, and also contains at least one of polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), perfluoroalkoxyalkane (PFA), perfluoroethylene propene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), and ethylene chlorotrifluoroethylene copolymer (ECTFE); The fluorine atom ratio measured by X-ray photoelectron spectroscopy (XPS) on the surface of the substrate opposite to the pressure-sensitive adhesive layer is 0.01 atm % or more and 2.5 atm % or less. A workpiece processing sheet characterized by:

2. 2. The workpiece processing sheet according to claim 1, wherein the fluorine atomic ratio is 0.35 atm % or more.

3. A work processing sheet as described in claim 1 or 2, characterized in that the base material has ether-based thermoplastic polyurethane as its main component and also contains polytetrafluoroethylene powder.

4. The workpiece processing sheet according to any one of claims 1 to 3, characterized in that the static friction force measured between the substrate side surface of the workpiece processing sheet and an aluminum plate in accordance with JIS K7125:1999 at a load of 1.96 N and a tensile speed of 100 mm / min is 0.001 N or more and 4.0 N or less.

5. The workpiece processing sheet according to any one of claims 1 to 4, characterized in that the base material has a breaking elongation of 400% or more and 1000% or less in a tensile test carried out at 23°C.

6. The workpiece processing sheet according to any one of claims 1 to 5, characterized in that the base material has a breaking strength of 20 N / 15 mm or more and 90 N / 15 mm or less in a tensile test conducted at 23 ° C.

7. A lamination step of laminating a plurality of workpieces on the adhesive layer side of the workpiece processing sheet according to any one of claims 1 to 6; an expanding step of stretching the workpiece processing sheet on which the plurality of workpieces are stacked to separate the plurality of workpieces from one another; A workpiece machining method comprising:

8. Use of the workpiece processing sheet according to any one of claims 1 to 6 for a workpiece processing method, The workpiece machining method includes: a lamination step of laminating a plurality of workpieces on the adhesive layer side of the workpiece processing sheet; an expanding step of stretching the workpiece processing sheet on which the plurality of workpieces are stacked to separate the plurality of workpieces from one another; The use characterized by comprising:

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