Method for forming an energy ray-curable protective film sheet and a workpiece with the protective film

Abstract

This invention provides a method for reliably removing unnecessary portions and forming protective film of a desired shape during the die-cutting process of protective film-forming films. [Solution] The energy-ray curable protective film forming sheet 10 has a heavy-side release film 12 provided on one side of the energy-ray curable protective film forming film 11 and a light-side release film 13 provided on the other side of the energy-ray curable protective film forming film, wherein the Young's modulus of the energy-ray curable protective film forming film before energy-ray irradiation is 6 MPa or more, the peeling force F1 of the heavy-side release film from the protective film forming film is 100 mN / 100 mm or more and 200 mN / 100 mm or less, the peeling force F2 of the light-side release film from the protective film forming film is 30 mN / 100 mm or more and 100 mN / 100 mm or less, and the difference between the peeling force F1 and the peeling force F2 (F1-F2) is 50 mN / 100 mm or more and 160 mN / 100 mm or less.

Description

[Technical Field]

[0001] The present invention relates to an energy-ray curable protective film forming sheet and a method for manufacturing a workpiece with a protective film using the same. In particular, the present invention relates to an energy-ray curable protective film forming sheet comprising an energy-ray curable protective film forming film suitably used for generating a protective film by energy rays for protecting workpieces such as semiconductor wafers or workpiece fragments such as semiconductor chips obtained by processing a workpiece, and to a method for manufacturing a workpiece with a protective film using the energy-ray curable protective film forming sheet. [Background technology]

[0002] In recent years, semiconductor devices have been manufactured using a mounting method called flip-chip bonding. In this method, when mounting a semiconductor chip that has a circuit surface with convex electrodes such as bumps, the circuit surface side of the semiconductor chip is flipped (face down) onto the chip mounting area and bonded. As a result, the back side of the semiconductor chip, where no circuit is formed, is exposed.

[0003] For this reason, a hard protective film made of organic material is often formed on the back side of a semiconductor chip to protect it from impacts during transport and other situations. The protective film is formed, for example, by attaching a curable protective film to the back side of a semiconductor wafer and then curing the protective film.

[0004] To form such a protective film, for example, a protective film forming sheet is used, which comprises a protective film forming film on a support sheet. In the protective film forming sheet, a protective film can be formed by the curing of the protective film forming film, and the support sheet can be used as a dicing sheet, making it possible to integrate the protective film forming film and the dicing sheet.

[0005] As such protective film-forming sheets, those equipped with a thermosetting protective film-forming film that hardens upon heating to form a protective film have been primarily used. In this case, for example, the protective film-forming sheet is attached to the back surface of the semiconductor wafer (the surface opposite to the electrode-forming surface) using a thermosetting protective film-forming film. The protective film-forming film is then hardened by heating to form a protective film, and the semiconductor wafer is divided together with the protective film by dicing to form semiconductor chips. The semiconductor chips are then picked up by pulling them away from the support sheet while the protective film is still attached.

[0006] However, the heat curing of thermosetting protective film formations typically takes several hours, so shortening the curing time is desirable. Furthermore, during the heat curing of the protective film formation, the support sheet is also heated and softened. This softened support sheet can fuse to the heating and dicing equipment, making subsequent removal difficult.

[0007] To resolve this problem, the use of protective film-forming films that can be cured by irradiation with energy rays such as ultraviolet light is being considered. For example, Patent Document 1 discloses an energy ray-curable protective film-forming film and a protective film-forming sheet containing the same, which contains a filler with an average particle size of 0.08 to 15 μm, and the filler content is 5 to 83% by mass relative to the mass of the protective film-forming film. By containing an appropriate amount of filler, this protective film-forming film suppresses adhesion to other components after protective film formation, improving suitability for various processes. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International release WO2017 / 188196 [Overview of the project] [Problems that the invention aims to solve]

[0009] In addition to Patent Document 1, various other protective film-forming sheets have been proposed that have an energy-ray curable protective film-forming film. Most of these are "pre-cut" types in which the protective film-forming film on a support sheet is pre-cut into a predetermined shape. In pre-cut protective film-forming sheets, the protective film-forming film is pre-cut into a closed shape to match the shape of the back surface of the workpiece to which the protective film-forming film is attached. The protective film-forming sheets are stored and transported in a roll.

[0010] However, in pre-cut protective film-forming sheets, there is a difference in height between the areas where the protective film-forming film is present and the areas where it is not. When this is wound into a roll, winding marks may occur in the protective film-forming film. Because the thickness of the protective film-forming film with winding marks is not uniform, the adhesion of the protective film-forming film to the workpiece becomes uneven, and the appearance of the protective film obtained by curing it is also impaired.

[0011] Furthermore, many protective film-forming sheets use adhesive sheets as support sheets. However, because the support sheet is adhesive, when transferring the protective film-forming film to the workpiece, some of the film may remain on the support sheet, resulting in poor transfer of the protective film-forming film. In addition, in the pre-cutting process where the protective film-forming film is punched out to match the shape of the back surface of the workpiece, when removing the unnecessary parts other than the closed-shaped parts punched out to match the shape of the workpiece, the unnecessary parts may adhere to the support sheet and cannot be removed.

[0012] For this reason, instead of pre-cutting, a non-die-cut protective film-forming sheet is sometimes attached to the workpiece, and then the unnecessary outer edges of the protective film-forming sheet are cut off with a cutter to match the shape of the workpiece. However, when the unnecessary outer edges are cut off, chips may be generated. If these chips adhere to the protective film-forming film, the adhesion of the protective film-forming film to the workpiece becomes uneven, and the appearance of the protective film obtained after curing is also impaired.

[0013] Therefore, in order to prevent the occurrence of winding marks on the protective film-forming film, it was considered to use only a release film as a support sheet and to perform die-cutting of the protective film-forming film immediately before attaching it to the workpiece. In this embodiment of the protective film-forming sheet, the protective film-forming film is sandwiched between two release films (hereinafter referred to as "first release film" and "second release film") without being die-cut. As a result, the thickness of the protective film-forming sheet is uniform, so even when wound into a roll, the occurrence of winding marks on the protective film-forming film can be prevented. In addition, since a die is used instead of a cutter when die-cutting the protective film-forming film, the generation of chips during die-cutting is reduced, and the adhesion of foreign matter to the protective film-forming film can be reduced.

[0014] In the die-cutting process, a protective film-forming sheet consisting of a first release film, a second release film, and a protective film-forming film sandwiched between them is punched out into a closed shape substantially identical to the back surface of the workpiece, while creating cuts in the first release film without completely punching it out. Subsequently, the second release film is completely peeled off, and any unnecessary portions of the protective film-forming film other than the closed shape are peeled off and removed, leaving the protective film-forming film in a closed shape substantially identical to the back surface of the workpiece on the first release film. After that, the workpiece is attached to the protective film-forming film on the first release film.

[0015] However, the following problems sometimes occurred during the punching process described above. (1) When the unnecessary portion of the protective film is peeled off, a part of it tears off and a portion of the unnecessary portion remains on the first release film. (2) When the second release film and the unwanted portion are peeled off, part or all of the "closed protective film-forming film" that is left on the first release film is peeled off together with the second release film and the unwanted portion, and a protective film-forming film of the desired shape cannot be obtained.

[0016] Accordingly, an object of the present invention is to use a protective film-forming sheet consisting of two release films and a protective film-forming film sandwiched therebetween, when the protective film-forming film is punched immediately before being attached to a workpiece, to reliably remove unnecessary portions and reliably form a protective film-forming film having a desired shape. [Means for Solving the Problem]

[0017] Aspects of the present invention that solve such problems are as follows. (1) An energy ray-curable protective film-forming film for forming a protective film, a higher-adhesion release film provided on one surface of the energy ray-curable protective film-forming film, and a lower-adhesion release film provided on the other surface of the energy ray-curable protective film-forming film, wherein the Young's modulus of the energy ray-curable protective film-forming film before energy ray irradiation is 6 MPa or more, the peel force F1 of the higher-adhesion release film from the energy ray-curable protective film-forming film before energy ray irradiation is 100 mN / 100 mm or more and 200 mN / 100 mm or less, the peel force F2 of the lower-adhesion release film from the energy ray-curable protective film-forming film before energy ray irradiation is 30 mN / 100 mm or more and 100 mN / 100 mm or less, and the difference (F1-F2) between the peel force F1 and the peel force F2 is 50 mN / 100 mm or more and 160 mN / 100 mm or less, an energy ray-curable protective film-forming sheet.

[0018] (2) The energy ray-curable protective film-forming sheet according to (1), wherein when the polished surface of a silicon wafer polished with #6000 abrasive is attached to the energy ray-curable protective film-forming film, the adhesive force between the silicon wafer and the energy ray-curable protective film-forming film before irradiating the energy ray-curable protective film-forming film with energy rays is 500 mN / 25 mm or more and 3000 mN / 25 mm or less.

[0019] (3) The energy ray-curable protective film-forming sheet according to (1), wherein when the energy ray-curable protective film-forming film is attached to the polished surface of a #6000-polished silicon wafer, and the energy ray-curable protective film-forming film is irradiated with energy rays to form a protective film from the energy ray-curable protective film-forming film, the peeling force of the protective film from the silicon wafer is 3.0 N / 10 mm or more.

[0020] (4) The energy ray-curable protective film-forming sheet according to (1), wherein after the energy ray-curable protective film-forming film is irradiated with energy rays to form a protective film from the energy ray-curable protective film-forming film, the absorbance of the protective film to light having a wavelength of 532 nm is 70% or more and 95% or less.

[0021] (5) The energy ray-curable protective film-forming sheet according to any one of (1) to (4), which is used for manufacturing a workpiece with a protective film by the steps of: temporarily attaching a workpiece onto an adhesive sheet; attaching the energy ray-curable protective film-forming film of the energy ray-curable protective film-forming sheet to the workpiece to obtain a workpiece with a protective film-forming film; irradiating the energy ray-curable protective film-forming film with energy rays to form a protective film from the energy ray-curable protective film-forming film; and then peeling the adhesive sheet off from the workpiece.

[0022] (6) Temporarily attaching a workpiece onto an adhesive sheet, punching the light surface release film and the energy ray-curable protective film-forming film of the energy ray-curable protective film-forming sheet according to any one of (1) to (4) into a closed shape substantially the same as the back surface of the workpiece, and forming a cut so as not to completely punch through the heavy surface release film, peeling off all of the light surface release film and unnecessary portions of the energy ray-curable protective film-forming film other than the closed shape, and leaving the energy ray-curable protective film-forming film having a closed shape substantially the same as the back surface of the workpiece on the heavy surface release film, An energy-curable protective film-forming film having a closed shape substantially identical to the back surface of the workpiece is attached to the back surface of the workpiece to create a workpiece with a protective film-forming film. The energy ray-curable protective film-forming film is irradiated with energy rays to form a protective film. The adhesive sheet is peeled off from the workpiece. A method for manufacturing a workpiece with a protective coating. [Effects of the Invention]

[0023] According to the present invention, when the protective film forming film is die-cut immediately before being attached to the workpiece, unnecessary portions can be reliably removed and a protective film forming film of the desired shape can be reliably formed. [Brief explanation of the drawing]

[0024] [Figure 1] Figure 1 is a schematic cross-sectional view of the energy ray curable protective film forming sheet according to this embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing the main steps of a method for manufacturing a workpiece with a protective film using an energy-curable protective film forming sheet according to this embodiment. [Modes for carrying out the invention]

[0025] First, we will explain the main terms used in this specification.

[0026] The workpiece is a plate-like body to which a protective film and protective film are attached and processed. Examples of workpieces include wafers and panels. Specifically, semiconductor wafers and semiconductor panels are examples. Examples of individualized workpieces include chips obtained by individualizing a wafer. Specifically, semiconductor chips obtained by individualizing a semiconductor wafer are exemplified. In this case, the protective film is formed on the back side of the wafer and chip.

[0027] The "surface" of a workpiece such as a wafer refers to the side on which circuits and convex electrodes such as bumps are formed, while the "back" refers to the side on which circuits, electrodes (such as convex electrodes such as bumps) are not formed.

[0028] The protective film-forming film is transferred to the workpiece and functions as a film that forms a protective film upon curing. Energy ray curability means the property of curing when exposed to energy rays. Energy rays refer to electromagnetic waves or charged particle beams that have energy quanta. Examples of energy rays include ultraviolet rays, radiation, and electron beams. Ultraviolet rays can be irradiated, for example, by using high-pressure mercury lamps, fusion lamps, xenon lamps, black lights, or LED lamps as ultraviolet light sources. Electron beams can be irradiated using those generated by electron accelerators, etc.

[0029] In this specification, for example, "(meth)acrylate" is used to refer to both "acrylate" and "methacrylate," and the same applies to other similar terms.

[0030] A release film is a film that supports a protective film in a way that allows it to be peeled off. The term "film" is used as a general concept that includes sheets, without limiting the thickness. Heavy-duty release films and light-duty release films are distinguished by their peeling force from the protective film. If the peeling force of a heavy-duty release film from the protective film is F1 and the peeling force of a light-duty release film from the protective film is F2, then the relationship F1 > F2 is satisfied.

[0031] In the descriptions of compositions for protective film formation and compositions for release agent layers, the mass ratios are based on the active ingredients (solid content), and unless otherwise specified, the solvent is not included.

[0032] The present invention will now be described based on specific embodiments. As shown in Figure 1, the energy-ray curable protective film forming sheet 10 comprises an energy-ray curable protective film forming film 11 (hereinafter sometimes simply referred to as "protective film forming film"), a heavy-side release film 12 provided on one side of the protective film forming film 11, and a light-side release film 13 provided on the other side. Such an energy-ray curable protective film forming sheet is usually a long sheet and is wound into a roll shape without any cuts being formed in the protective film forming film.

[0033] (1. Energy ray curable protective film-forming film) Examples of protective films obtained by forming an energy-ray curable protective film include protective films for protecting workpieces or individual workpiece fragments.

[0034] "To create a protective film" means to bring the protective film-forming film 11 into a state where it has sufficient properties to protect the workpiece or workpiece fragments. Specifically, "to create a protective film" of the energy-ray curable protective film-forming film according to this embodiment means to irradiate the uncured protective film-forming film with energy rays to cure it. In other words, the protected film-forming film is a cured product of the protective film-forming film and is different from the protective film-forming film itself.

[0035] Furthermore, it is preferable that the protective film-forming film is adhesive at room temperature (23°C) or becomes adhesive upon heating. This allows the workpiece to be bonded to the protective film-forming film when it is placed on top of it. Therefore, positioning can be reliably performed before the protective film-forming film hardens.

[0036] The protective film may consist of one layer (single layer) or of two or more layers. If the protective film has multiple layers, these layers may be identical or different, and there are no particular restrictions on the combination of layers that make up these multiple layers.

[0037] In this embodiment, it is preferable that the protective film-forming film is a single layer. If the protective film-forming film is composed of multiple layers, there is a risk of delamination occurring between layers due to differences in thermal expansion and contraction between layers during processes where temperature changes occur (such as reflow processing or when using the equipment), but this risk can be reduced if it is a single layer.

[0038] The thickness of the protective film-forming film is not particularly limited, but is preferably 100 μm or less, more preferably 70 μm or less, even more preferably 50 μm or less, and particularly preferably 40 μm or less. It is also preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, and particularly preferably 20 μm or more. When the thickness of the protective film-forming film is within the above range, the workability when punching out the energy ray curable protective film-forming sheet is excellent, and the protective performance of the resulting protective film is good.

[0039] Note that the thickness of the protective film refers to the total thickness of the protective film. For example, the thickness of a protective film composed of multiple layers refers to the sum of the thicknesses of all the layers that make up the protective film.

[0040] In the case of a protective-filmed workpiece, a protective-filmed chip is formed on the back side of the chip (the side without a circuit). Circuits and electrodes are formed on the front side of the chip, and the electrodes are formed to be electrically connected to the circuit. The protective-filmed chip is positioned so that the side with the electrodes faces the substrate for chip mounting. Subsequently, it is mounted by a predetermined heat treatment (reflow treatment) through which it is electrically and mechanically bonded to the substrate via the electrodes. Examples of electrodes include bump electrodes and pillar electrodes.

[0041] (1.1 Properties of protective film or protective film) (1.1.1 Young's modulus of protective film) In this embodiment, the Young's modulus of the protective film-forming film before energy ray irradiation (i.e., before curing) is 6 MPa or higher, preferably 7.5 MPa or higher, more preferably 9 MPa or higher, and particularly preferably 10.5 MPa or higher. Having the Young's modulus of the protective film-forming film within the above range before energy ray irradiation ensures that the protective film-forming film has adequate strength, allowing for stable punching of the protective film-forming film, and enabling continuous and reliable removal of unwanted portions without tearing the protective film-forming film.

[0042] There is no particular upper limit to the Young's modulus of the protective film before energy ray irradiation, however, if the Young's modulus is excessively high, adhesion to the workpiece may decrease. For this reason, the Young's modulus of the protective film before energy ray irradiation is preferably 30 MPa or less, more preferably 20 MPa or less, and particularly preferably 15 MPa or less.

[0043] The Young's modulus of the protective film before energy ray irradiation can be controlled by appropriately selecting the components of the protective film composition described later.

[0044] (1.1.2 Peeling characteristics of protective film-forming film) In this embodiment, if F1 is the peeling force of the heavy-surface release film from the energy-curable protective film-forming film before energy-ray irradiation, and F2 is the peeling force of the light-surface release film from the energy-curable protective film-forming film before energy-ray irradiation, then F1 > F2. That is, the release film with the higher peeling force is called the heavy-surface release film, and the one with the lower peeling force is called the light-surface release film.

[0045] The peeling force F1 of the heavy-surface peel film from the energy-curable protective film-forming film before energy ray irradiation is 100 mN / 100 mm or more and 200 mN / 100 mm or less, preferably 120 mN / 100 mm or more and 200 mN / 100 mm or less, more preferably 140 mN / 100 mm or more and 200 mN / 100 mm or less, and particularly preferably 160 mN / 100 mm or more and 200 mN / 100 mm or less.

[0046] The peeling force F2 of the light-surface peel film from the energy-curable protective film-forming film before energy ray irradiation is 30 mN / 100 mm or more and 100 mN / 100 mm or less, preferably 40 mN / 100 mm or more and 100 mN / 100 mm or less, more preferably 50 mN / 100 mm or more and 100 mN / 100 mm or less, and particularly preferably 60 mN / 100 mm or more and 100 mN / 100 mm or less.

[0047] Furthermore, the difference between the peeling force F1 and the peeling force F2 (F1-F2) is 50mN / 100mm or more and 160mN / 100mm or less, preferably 60mN / 100mm or more and 150mN / 100mm or less, even more preferably 70mN / 100mm or more and 140mN / 100mm or less, and particularly preferably 80mN / 100mm or more and 130mN / 100mm or less.

[0048] When the peeling forces F1 and F2 are within the above range, the protective film forming film is punched into a closed shape, and then the light-side release film and the unnecessary parts around the closed shape are removed, leaving the closed-shape protective film forming film (hereinafter sometimes referred to as the "used portion") on the heavy-side release film. In this process, the used portion does not come along with the light-side release film, but is reliably left on the heavy-side release film.

[0049] The peel characteristics of the protective film before energy ray irradiation can be controlled by appropriately selecting the components of the protective film composition described later. It can also be controlled by peeling treatments of the heavy-sided and light-sided release films.

[0050] (1.1.3 Adhesive properties of protective film-forming film) In this embodiment, it is preferable that the protective film-forming film has appropriate adhesive strength to the workpiece before energy ray irradiation. In this embodiment, the adhesive strength of the protective film-forming film is evaluated by its adhesive strength to a polished silicon wafer. Specifically, as the silicon wafer, a silicon wafer polished with a #6000 grinding wheel (finishing stone) to a surface roughness Ra of 7.5 nm ± 1.5 nm (referred to herein as "#6000 polished silicon wafer") was used. The polished surface of the #6000 polished silicon wafer is attached to the protective film-forming film, and the adhesive strength between the silicon wafer and the protective film-forming film before energy ray irradiation of the protective film-forming film is preferably 500 mN / 25 mm to 3000 mN / 25 mm, more preferably 650 mN / 25 mm to 2500 mN / 25 mm, and particularly preferably 800 mN / 25 mm to 2000 mN / 25 mm.

[0051] If the adhesive strength of the protective film before energy ray irradiation is within the above range, it will have excellent suitability for attachment to the workpiece. If the adhesive strength of the protective film before energy ray irradiation is too low, it will be difficult to attach it to the workpiece. Conversely, if the adhesive strength is too high, it will be impossible to peel it off when reattaching it to the workpiece, making it impossible to redo the attachment process.

[0052] The adhesive properties of the protective film before energy ray irradiation can be controlled by appropriately selecting the components of the protective film composition described later.

[0053] (1.1.4 Peeling characteristics of the protective film) In this embodiment, it is preferable that the protective film obtained by curing the protective film-forming film adheres firmly to the workpiece or its fragments. In this embodiment, the adhesion of the protective film to the workpiece is evaluated by the peeling force of the protective film from the polished silicon wafer. Specifically, after attaching the polished surface of a silicon wafer polished to #6000 to the protective film-forming film and irradiating the protective film-forming film with energy rays to form a protective film, the peeling force of the protective film from the silicon wafer is preferably 3.0 N / 10 mm or more, more preferably 4.0 N / 10 mm or more, and particularly preferably 5.0 N / 10 mm or more. When the peeling force of the protective film is within the above range, the adhesion of the protective film to the workpiece becomes strong, and the workpiece can be reliably protected.

[0054] There is no particular upper limit to the peeling force of the protective film, but it should generally be capped at 15 N / 10 mm.

[0055] The peeling force of the protective film can be controlled by appropriately selecting the components of the protective film-forming film composition described later.

[0056] (1.1.5 Light absorption rate of the protective film) In this embodiment, the protective film obtained by curing the protective film-forming film is usually marked with a laser beam. The marking indicates the attributes of the workpiece on which the protective film is formed, for example, the product name, part number, etc., are printed with a laser beam. Marking is performed by absorbing the energy irradiated by the laser beam, causing a portion of the protective film to evaporate, denature, and decompose. For this reason, it is preferable that the protective film has the property of moderately absorbing laser beams. In this embodiment, the marking suitability of the protective film is evaluated by the absorption rate of light with approximately the same wavelength as the light beam used for laser marking. That is, the absorption rate of the protective film with a wavelength of 532 nm is preferably 70% to 95%, more preferably 73% to 94%, and particularly preferably 78% to 93%.

[0057] If the light absorption rate is too low, the marking may not be performed properly, leading to poor recognition of the mark. Conversely, if the absorption rate is too high, the protective film in the marked area may evaporate and decompose excessively, causing the laser light to irradiate the workpiece itself and potentially damaging it.

[0058] The light absorption rate of the protective film can be controlled by appropriately selecting the components of the protective film-forming film composition described later.

[0059] (1.2 Composition for energy ray curable protective film-forming film) The composition of the protective film-forming film is not particularly limited as long as the energy-ray-curable protective film-forming film has the above-mentioned physical properties. In this embodiment, the composition constituting the protective film-forming film (composition for protective film-forming film) is preferably a resin composition containing at least a polymer component (A), an energy-ray-curable component (B), a filler (C), and a photopolymerization initiator (D). The polymer component is a component that can be considered to have been formed by a polymerization reaction of a polymerizable compound. The energy-ray-curable component is a component that can undergo a curing (polymerization) reaction when irradiated with energy rays. In this invention, the polymerization reaction also includes polycondensation reactions.

[0060] Furthermore, components contained in polymer components may also be energy-ray curable components. In this embodiment, if a protective film-forming film composition contains components that are both polymer components and energy-ray curable components, the protective film-forming film composition is considered to contain both polymer components and energy-ray curable components.

[0061] (1.2.1 Polymer Component (A)) Polymer component (A) provides the protective film-forming film with appropriate tack while giving it film-forming properties, ensuring uniform adhesion of the protective film to the workpiece. The weight-average molecular weight of the polymer component is usually in the range of 50,000 to 2,000,000, preferably 100,000 to 1,500,000, and particularly preferably 200,000 to 1,000,000. If the weight-average molecular weight is too low, the peeling force of the release film tends to increase. On the other hand, if the weight-average molecular weight is too high, the compatibility with other components deteriorates, and as a result, uniform film formation is hindered. Examples of such polymer components include acrylic resin, urethane resin, phenoxy resin, silicone resin, saturated polyester resin, etc., with acrylic resin being particularly preferred.

[0062] In this specification, unless otherwise specified, "weight-average molecular weight" refers to the polystyrene-converted value measured by gel permeation chromatography (GPC). Such measurements are performed, for example, using a high-speed GPC instrument "HLC-8120GPC" manufactured by Tosoh Corporation with a high-speed column "TSK gurd column H XL -H", "TSK Gel GMH" XL "TSK Gel G2000 H XL The following components (all manufactured by Tosoh Corporation) are connected in this order, and the test is performed with a column temperature of 40°C and a liquid delivery rate of 1.0 mL / min, using a differential refractometer as the detector.

[0063] Examples of acrylic resins include (meth)acrylic acid ester copolymers, which consist of (meth)acrylic acid ester monomers and structural units derived from (meth)acrylic acid derivatives. Here, examples of (meth)acrylic acid ester monomers include alkyl (meth)acrylic acid esters having 1 to 18 carbon atoms in the alkyl group, specifically methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, etc. Examples of (meth)acrylic acid derivatives include (meth)acrylic acid, glycidyl (meth)acrylate, hydroxyethyl (meth)acrylate, etc.

[0064] In this embodiment, it is preferable to introduce hydroxyl groups into the acrylic resin using hydroxyethyl acrylate or the like in order to control the adhesion and tackiness to the workpiece.

[0065] The glass transition temperature of the acrylic resin is preferably -70°C to 40°C, more preferably -35°C to 35°C, even more preferably -20°C to 30°C, still more preferably -10°C to 25°C, and particularly preferably -5°C to 20°C. By setting the glass transition temperature of the acrylic resin within the above range, the fluidity of the protective film-forming film is suppressed, making it easier to obtain a smooth protective film. If the glass transition temperature is too low, the peeling force of the release film tends to increase. If the glass transition temperature is too high, the compatibility with other components deteriorates, resulting in the formation of a uniform film and a tendency for the peeling force F2 of the light-surface release film to decrease excessively.

[0066] When an acrylic resin has m types of constituent units (where m is an integer greater than or equal to 2), the glass transition temperature of the acrylic resin can be calculated as follows. That is, if m types of monomers that induce the constituent units in the acrylic resin are each assigned a unique number from 1 to m and named "monomer m", the glass transition temperature (Tg) of the acrylic resin can be calculated using Fox's formula shown below.

[0067]

number

[0068]

number

[0069] For Tgk, values ​​listed in the Polymer Data Handbook, Adhesion Handbook, or Polymer Handbook can be used. For example, the Tgk of methyl acrylate homopolymer is 10°C, the Tgk of n-butyl acrylate homopolymer is -54°C, the Tgk of methyl methacrylate homopolymer is 105°C, the Tgk of 2-hydroxyethyl acrylate homopolymer is -15°C, the Tgk of glycidyl methacrylate homopolymer is 41°C, the Tgk of 2-ethylhexyl acrylate homopolymer is -70°C, and the Tgk of acryloyl morpholine homopolymer is 145°C.

[0070] The content of polymer component (A) when the total weight of the protective film-forming composition is 100 parts by mass is preferably 5 to 80 parts by mass, more preferably 8 to 70 parts by mass, more preferably 10 to 60 parts by mass, even more preferably 12 to 55 parts by mass, even more preferably 14 to 50 parts by mass, and particularly preferably 15 to 45 parts by mass. By keeping the polymer component content within the above range, the amount of low molecular weight component that increases the peeling force of the release film is limited to an appropriate range, thus making the material design of the protective film-forming composition easier.

[0071] (1.2.2 Energy ray curing component (B)) Energy-ray curable components are components that harden when irradiated with energy rays, and are also components that impart film-forming properties, flexibility, and other characteristics to protective film-forming films.

[0072] As the energy ray curable component, for example, a compound having an energy ray curable group is preferred. Examples of energy ray curable groups include groups containing an energy ray curable double bond, and preferred examples include (meth)acryloyl groups and vinyl groups.

[0073] Non-limiting examples include the following compounds: (b1) Oligomers having energy-ray curable groups and a weight-average molecular weight of 1700 to 20000 (energy-ray curable oligomers) (b2) Low molecular weight compounds having an energy ray curable group and a number average molecular weight of 100 to 1500 (energy ray curable low molecular weight compounds)

[0074] (Energy-ray curable oligomer (b1)) The energy-ray curable oligomer (b1) is not particularly limited as long as it satisfies the above conditions, but examples include urethane oligomers having (meth)acryloyl groups, dendrimer-type oligomers or hyperbranch-type oligomers having (meth)acryloyl groups.

[0075] The weight-average molecular weight (Mw) of component (b1) is preferably 1700 to 20000, more preferably 2000 to 15000, and even more preferably 2000 to 12000. The number of (meth)acryloyl groups, which are energy-ray curable groups in component (b1) (i.e., the number of (meth)acryloyl groups per molecule, hereinafter also referred to as "number of functional groups") may be monofunctional, difunctional, or trifunctional or more, but monofunctional or difunctional is preferred, and difunctional is more preferred. Component (b1) may be used alone or in combination of two or more types.

[0076] A urethane oligomer having a (meth)acryloyl group is a compound having at least a (meth)acryloyl group and a urethane bond, and possesses the property of polymerization curing by energy ray irradiation. For example, it can be obtained by reacting a (meth)acrylate having a hydroxyl group with a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound with a polyvalent isocyanate compound.

[0077] The polyol compound used as a raw material is not particularly limited as long as it is a compound having two or more hydroxyl groups. It may be a bifunctional diol, a trifunctional triol, or a polyol with four or more functions, but a bifunctional diol is preferred, and a polyolefin-type diol is more preferred.

[0078] Furthermore, examples of polyvalent isocyanate compounds used as raw materials include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, and ω,ω'-diisocyanate dimethylcyclohexane; and aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, and naphthalene-1,5-diisocyanate.

[0079] A urethane oligomer having a (meth)acryloyl group can be obtained by reacting the above-mentioned polyol compound with a polyvalent isocyanate compound to obtain a terminal isocyanate urethane prepolymer, and then reacting the (meth)acrylate having a hydroxyl group with the (meth)acrylate having a hydroxyl group with the (meth)acrylate having a hydroxyl group. The (meth)acrylate having a hydroxyl group is not particularly limited as long as it is a compound having at least one molecule containing both a hydroxyl group and a (meth)acryloyl group.

[0080] Specific examples of (meth)acrylates having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, 5-hydroxycyclooctyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, polyethylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate.

[0081] The conditions for reacting the terminal isocyanate urethane prepolymer and the (meth)acrylate having a hydroxyl group are preferably such that the reaction is carried out at 60-100°C for 1-4 hours in the presence of a solvent and catalyst, which may be added as needed.

[0082] The urethane oligomer having a (meth)acryloyl group may also have a carboxyl group, amide group, amino group, or hydroxyl group as a polar group. In particular, a urethane oligomer having an acrylamide group and an amide group derived from the acrylamide group may also be used.

[0083] By including a urethane oligomer having polar groups such as amide groups in the protective film-forming film, the cohesiveness of the protective film-forming film is increased, making it easier to control the Young's modulus of the protective film-forming film within the aforementioned range, and reducing the peeling force of the release film and the adhesive force of the protective film-forming film to the workpiece, making it easier to control them within the aforementioned range.

[0084] Examples of urethane oligomers having amide groups derived from acrylamide groups include the Quick Cure series, such as Quick Cure® 7100 and Quick Cure 8100, manufactured by KJ Chemicals Co., Ltd.

[0085] When a urethane oligomer having a (meth)acryloyl group is included, the amount is preferably 30 to 80 parts by mass, more preferably 40 to 70 parts by mass, and even more preferably 45 to 65 parts by mass, per 100 parts by mass of the energy ray curable component (B).

[0086] In this specification, a dendrimer-type oligomer or hyperbranched oligomer having a (meth)acryloyl group is defined as having a chemical structure in which the chemical structure constituting the core repeatedly branches outward in a regular manner, with a (meth)acryloyl group bonded to the end of each branch.

[0087] Examples of dendrimer-type oligomers or hyperbranch-type oligomers having a (meth)acryloyl group include Viscoat #1000LT and SIRUS-501 from Osaka Organic Chemical Industry Co., Ltd., and CN2300, CN2301, and CN2320 from Sartomer Co., Ltd.

[0088] When a dendrimer-type oligomer or hyperbranch-type oligomer having a (meth)acryloyl group is included, the amount is preferably 1 to 30 parts by mass, more preferably 5 to 25 parts by mass, and even more preferably 10 to 20 parts by mass, per 100 parts by mass of the energy ray curable component (B).

[0089] Energy-ray curable oligomers (b1) may be a combination of two or more types.

[0090] The content of component (b1) in the protective film-forming film composition is preferably 5 to 30 parts by mass, more preferably 7 to 25 parts by mass, and even more preferably 9 to 18 parts by mass, based on the total amount (100 parts by mass) of the protective film-forming film composition.

[0091] (Energy-ray curable low molecular weight compound (b2)) Energy-ray curable low molecular weight compounds are not particularly limited as long as they satisfy the above conditions, but examples include low molecular weight compounds having a (meth)acryloyl group and a carboxyl group, amide group, amino group or hydroxyl group, and low molecular weight compounds having a (meth)acryloyl group and a fluorene skeleton.

[0092] The number-average molecular weight (Mn) of component (b2) is preferably 100 to 1500, more preferably 200 to 1400, and even more preferably 300 to 1300. The number of (meth)acryloyl groups, which are energy-ray curable groups in component (b2), may be monofunctional, difunctional, or trifunctional or more, but monofunctional or difunctional is preferred, and difunctional is more preferred. Component (b2) may be used alone or in combination of two or more types.

[0093] Low molecular weight compounds having a (meth)acryloyl group and a carboxyl group, amide group, amino group, or hydroxyl group may be low molecular weight compounds having a heterocycle in which the nitrogen atom (N) constituting the amide group or amino group is a nitrogen atom (N) constituting the ring structure, or low molecular weight compounds having a carboxyl group, amide group, amino group, or hydroxyl group without having a heterocycle. Furthermore, low molecular weight compounds having a heterocycle in which the nitrogen atom (N) constituting the amide group or amino group is a nitrogen atom (N) constituting the ring structure, and also having a carboxyl group, amide group, amino group, or hydroxyl group separately from the heterocycle.

[0094] Low molecular weight compounds having a heterocyclic ring in which the nitrogen atom (N) constituting the amide or amino group is the same nitrogen atom (N) constituting the ring structure include low molecular weight compounds having a heterosix-membered ring. Specifically, examples include 1,4-bis(meth)acryloylpiperazine, tris(2-(meth)acryloxyethyl)isocyanurate, ε-caprolactone-modified tris-(2-(meth)acryloxyethyl)isocyanurate, and morpholine (meth)acrylate. These compounds do not have any other carboxyl groups, amide groups, amino groups, or hydroxyl groups besides the heterocyclic ring.

[0095] Low molecular weight compounds that do not have a heterocycle but have a carboxyl group, amide group, amino group or hydroxyl group include 3-((meth)acryloyloxy)propionic acid, 2-carboxyethyl (meth)acrylate, mono(2-(meth)acryloyloxyethyl) succinate, (meth)acrylamide, N-methyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-phenyl (meth)acrylamide, N,N'-methylenebis((meth)acrylamide), N,N'-ethylenebis((meth)acrylamide), N,N'-hexamethylenebis((meth)acrylamide), N-(meth)acryloyltris(hydroxymethyl)aminomethane, N-(tris(3-(meth)acrylamidepropoxymethyl)methyl)(meth)acrylamide, N, Examples include N'-1,2-ethanediylbis{N-[2-((meth)acryloylamino)ethyl](meth)acrylamide}, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycerol 1-(meth)acrylate, glycerol di(meth)acrylate, 3-(meth)acryloyloxyglycerol mono(meth)acrylate, dipentaerythritol penta(meth)acrylate, 2-(dimethylamino)ethyl (meth)acrylate, and 3-(dimethylamino)propyl (meth)acrylate.

[0096] Examples of low molecular weight compounds having a heterocycle in which the nitrogen atom (N) constituting the amide group or amino group is the same nitrogen atom (N) constituting the ring structure, and also having a carboxyl group, amide group, amino group, or hydroxyl group separately from the heterocycle, include Aronics M-215 manufactured by Toagosei Co., Ltd.

[0097] By including an energy-ray-curable low-molecular-weight compound having polar groups such as hydroxyl groups in the protective film, the cohesiveness of the protective film is increased, making it easier to control the Young's modulus of the protective film within the aforementioned range, and reducing the peeling force of the release film and the adhesive force of the protective film to the workpiece, making it easier to control them within the aforementioned range.

[0098] When a low molecular weight compound having a (meth)acryloyl group and a carboxyl group, amide group, amino group, or hydroxyl group is included, the amount of the compound is preferably 20 to 60 parts by mass, more preferably 30 to 50 parts by mass, per 100 parts by mass of the energy ray curable component (B).

[0099] Examples of low molecular weight compounds having a (meth)acryloyl group and a fluorene skeleton include 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxy-3-acryloyloxypropoxy)phenyl]fluorene (this compound also falls under the category of low molecular weight compounds having a (meth)acryloyl group and a hydroxyl group), and the OGSOL series from Osaka Gas Chemical Co., Ltd., such as OGSOL EA-0200, OGSOL EA-0300, OGSOL GA-2800, OGSOL GA-5060P, and OGSOL EA-F5710.

[0100] Because the protective film-forming film contains a low molecular weight compound having a fluorene skeleton, the bulkiness of the skeleton makes it easier to control the Young's modulus of the protective film-forming film within the aforementioned range.

[0101] When a low molecular weight compound having a (meth)acryloyl group and a fluorene skeleton is included, the amount of the compound is preferably 30 to 60 parts by mass, more preferably 35 to 50 parts by mass, per 100 parts by mass of the energy ray curable component (B).

[0102] Other examples of energy-ray-curable low molecular weight compounds (b2) include glycerol tri(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, divinylbenzene, isobornyl(meth)acrylate, dicyclopentanyl(meth)acrylate, cyclohexyl(meth)acrylate, and 1-adamantane(meth)acrylate.

[0103] Energy-ray-curable low molecular weight compounds (b2) may be a combination of two or more types.

[0104] The content of component (b2) in the protective film-forming film composition is preferably 1 to 20 parts by mass, more preferably 3 to 15 parts by mass, and even more preferably 5 to 12 parts by mass, based on the total amount (100 parts by mass) of the protective film-forming film composition.

[0105] As the energy ray curable component, it is particularly preferable to use in combination the above-mentioned energy ray curable oligomer (b1) and the component energy ray curable low molecular weight compound (b2). When the protective film-forming composition uses these components in combination, it is preferable to have a higher mass ratio of the energy ray curable oligomer (b1) than the energy ray curable low molecular weight compound (b2) in order to more easily control the Young's modulus of the protective film-forming film within the above-mentioned range, and to more easily control the peeling force of the release film and the adhesive force of the protective film-forming film to the workpiece within the above-mentioned range.

[0106] Other components besides the energy-ray-curable oligomer (b1) and the energy-ray-curable low molecular weight compound (b2) may be used as the energy-ray-curable component (B). Examples of such other components include general-purpose polymer energy-ray-curable compounds.

[0107] The content of the energy ray-curable component (B) when the total weight of the protective film-forming composition is 100 parts by mass is preferably 6 to 50 parts by mass, more preferably 10 to 40 parts by mass, and more preferably 14 to 30 parts by mass. By having the content of the energy ray-curable component within the above range, it is easier to control the Young's modulus of the protective film-forming film to the above range, and it is easier to control the peeling force of the release film and the adhesive force of the protective film-forming film to the workpiece to the above range. In addition, the protective performance of the resulting protective film tends to be better.

[0108] (1.2.3 Filler (C)) By including a filler (C) in the protective film-forming film, the thermal expansion coefficient of the protective film formed from the protective film-forming film can be easily adjusted. By bringing the thermal expansion coefficient of the protective film closer to that of the workpiece, the adhesive reliability of the package obtained using the protective film-forming film is further improved. In addition, the inclusion of filler (C) in the protective film-forming film results in a rigid protective film, further reducing the moisture absorption rate of the protective film, and thus further improving the adhesive reliability of the package.

[0109] The filler (C) may be either an organic filler or an inorganic filler, but an inorganic filler is preferred from the viewpoint of dimensional stability at high temperatures.

[0110] Preferred inorganic fillers include, for example, powders of silica, alumina, talc, calcium carbonate, red iron oxide, silicon carbide, boron nitride, etc.; beads formed from these inorganic fillers in a spherical shape; surface-modified products of these inorganic fillers; single-crystal fibers of these inorganic fillers; glass fibers, etc. Among these, silica and surface-modified silica are preferred. Surface-modified silica is preferably surface-modified with a coupling agent, and more preferably with a silane coupling agent.

[0111] The average particle size of the filler is preferably 0.02 to 10 μm, more preferably 0.05 to 5 μm, and particularly preferably 0.10 to 3 μm.

[0112] By setting the average particle size of the filler to the above value, the handling properties of the protective film-forming composition are improved. As a result, the quality of both the protective film-forming composition and the protective film-forming film tends to be more stable.

[0113] In this specification, "average particle size" refers to the particle diameter (D50) at 50% integration in the particle size distribution curve obtained by laser diffraction scattering, unless otherwise specified.

[0114] The upper limit of the filler content when the total weight of the protective film-forming composition is 100 parts by mass is preferably less than 80 parts by mass, more preferably less than 75 parts by mass, more preferably less than 70 parts by mass, and particularly preferably less than 65 parts by mass, and the lower limit is preferably 15 parts by mass or more, more preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and particularly preferably 45 parts by mass or more.

[0115] By setting the filler content to the values ​​mentioned above, it is easier to control the peeling force of the release film within an appropriate range. If the filler content is too low, the tack of the protective film will increase, and the peeling force of the release film will increase excessively. On the other hand, if the amount of filler is too high, the shape retention of the protective film may decrease. Also, if the amount of filler is too high, the tack of the protective film may decrease excessively, making it difficult to apply to the workpiece.

[0116] Furthermore, the protective film may contain two or more types of fillers. That is, filler (C) may be a mixture of two or more types of fillers. "Containing two or more types of fillers" means that it may contain two or more types of fillers with different materials, or two or more types of fillers with different average particle sizes.

[0117] (1.2.4 Photopolymerization Initiator (D)) The protective film-forming film composition preferably contains a photopolymerization initiator, from the viewpoint of shortening the polymerization time by energy ray irradiation and reducing the amount of energy ray irradiation when curing the protective film-forming film to form a protective film.

[0118] Examples of photopolymerization initiators include benzoin compounds, acetophenone compounds, acyl phosphinoxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones. More specifically, examples include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyrolnitrile, dibenzyl, diacetyl, 8-chloranthraquinone, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, α-hydroxyacetophenone, α-aminoalkylphenone, and benzyl ketal.

[0119] These photopolymerization initiators can be used individually or in combination of two or more.

[0120] The content of the photopolymerization initiator in the composition for forming a protective film, when the total weight is 100 parts by mass, is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.3 to 5 parts by mass.

[0121] (1.2.5 Colorants (E)) The protective film preferably contains a coloring agent (E). This conceals the back surface of individual workpieces such as chips, thereby blocking various electromagnetic waves generated within electronic devices and reducing malfunctions of individual workpieces such as chips. Furthermore, if any residue of the protective film remains on rollers such as tension rollers or cutting blades in the protective film application device, it can be immediately detected by visual inspection.

[0122] As the coloring agent (E), known substances such as inorganic pigments, organic pigments, and organic dyes can be used. In this embodiment, inorganic pigments are preferred.

[0123] Examples of inorganic pigments include carbon black, cobalt-based dyes, iron-based dyes, chromium-based dyes, titanium-based dyes, vanadium-based dyes, zirconium-based dyes, molybdenum-based dyes, ruthenium-based dyes, platinum-based dyes, ITO (indium tin oxide)-based dyes, and ATO (antimony tin oxide)-based dyes.

[0124] The amount of colorant blended in the protective film-forming film varies depending on the thickness of the protective film-forming film. For example, when the thickness of the protective film-forming film is 25 μm, the amount of colorant in the composition for the protective film-forming film is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and more preferably 0.05 to 4 parts by mass.

[0125] The average particle size of the colorant is preferably 1 to 500 nm, particularly preferably 3 to 100 nm, and even more preferably 5 to 50 nm. When the average particle size of the colorant is within the above range, it is easier to control the light reflectance within the desired range.

[0126] (1.2.6 Coupling agent (F)) The protective film-forming film may contain a coupling agent (F). By including a coupling agent, the adhesion between the protective film and the workpiece can be improved after the protective film-forming film has cured, without impairing the heat resistance of the protective film, and the water resistance (moisture and heat resistance) can also be improved. From the viewpoint of its versatility and cost-effectiveness, a silane coupling agent is preferred as the coupling agent.

[0127] Examples of silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-(methacryloxypropyl)trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfan, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazolesilane. These can be used individually or in combination of two or more.

[0128] Preferred silane coupling agents include oligomeric silane coupling agents having multiple alkoxysilyl groups in one molecule. These oligomeric silane coupling agents are preferred because they are less volatile and, having multiple alkoxysilyl groups in one molecule, are effective in improving durability. Examples of these oligomeric silane coupling agents include the epoxy group-containing oligomeric silane coupling agents "X-41-1053", "X-41-1059A", "X-41-1056", and "X-40-2651" (all manufactured by Shin-Etsu Chemical Co., Ltd.); and the mercapto group-containing oligomeric silane coupling agents "X-41-1818", "X-41-1810", and "X-41-1805" (all manufactured by Shin-Etsu Chemical Co., Ltd.).

[0129] The coupling agent content when the total weight of the protective film-forming composition is 100 parts by mass is preferably 0.01 to 20 parts by mass, 0.1 to 10 parts by mass, 0.2 to 5 parts by mass, or 0.3 to 3 parts by mass.

[0130] (1.2.7 Other additives) The protective film-forming composition may contain other additives, such as crosslinking agents, plasticizers, antistatic agents, antioxidants, gettering agents, tackifiers, release agents, and ultraviolet absorbers, to the extent that they do not impair the effects of the present invention.

[0131] However, in this embodiment, the content of the release agent when the total weight of the protective film-forming film composition is 100 parts by mass is preferably less than 0.00099 parts by mass. If the release agent content is too high, the adhesion reliability between the protective film and the workpiece tends to decrease. Examples of release agents include alkyd release agents, silicone release agents, fluorine-based release agents, unsaturated polyester release agents, polyolefin-based release agents, and wax-based release agents.

[0132] (1.2.8 Control of the properties of protective film-forming films and protective films) As described above, in this embodiment, the Young's modulus of the protective film-forming film before energy ray irradiation (i.e., before curing) is 6 MPa or higher. As previously mentioned, the Young's modulus of the protective film-forming film can be controlled by the types and amounts of each component that make up the protective film-forming film.

[0133] For example, increasing the content of filler (C) improves the Young's modulus of the protective film. However, if the content of filler (C) is excessively high, the adhesive strength of the protective film decreases, making it difficult to properly attach it to the workpiece. Therefore, as mentioned above, it is particularly preferable to use in combination an energy-ray curable component (B) that is a urethane oligomer (b1) having a (meth)acryloyl group and an energy-ray curable low molecular weight compound (b2) having the aforementioned polar group. When these components are used in combination, the polar group forms a pseudo-crosslinked structure in the protective film, making it easier to increase the Young's modulus of the protective film before curing.

[0134] Furthermore, in this embodiment, the peeling force F1 of the heavy-side release film from the energy-curable protective film-forming film before energy-ray irradiation is 100 mN / 100 mm or more and 200 mN / 100 mm or less. Also, the peeling force F2 of the light-side release film from the energy-curable protective film-forming film before energy-ray irradiation is 30 mN / 100 mm or more and 100 mN / 100 mm or less. Moreover, the difference between the peeling force F1 and the peeling force F2 (F1-F2) is 50 mN / 100 mm or more and 160 mN / 100 mm or less.

[0135] As mentioned above, the release properties of the protective film-forming film can be controlled by the types and amounts of each component that make up the protective film-forming film, the types of release agents for the heavy surface release film 12 and the light surface release film 13, and the manufacturing process of the energy ray curable protective film-forming sheet.

[0136] The peeling force tends to increase when the weight-average molecular weight of polymer component (A) is low. The peeling force also tends to increase when the glass transition temperature of polymer component (A) is low. Furthermore, the peeling force tends to increase when a low molecular weight compound is used as the energy ray curable component (B). The peeling force tends to decrease when the amount of filler (C) is high.

[0137] Furthermore, similar to controlling the Young's modulus, the peeling properties of the protective film can also be controlled by using, as the energy-ray curable component (B), a urethane oligomer (b1) having a (meth)acryloyl group and the aforementioned polar group, and an energy-ray curable low molecular weight compound (b2) having the aforementioned polar group. When these components are used together, the polar group forms a pseudo-crosslinked structure in the protective film, making it easier to reduce the peeling force of the protective film.

[0138] The peeling force can also be controlled by partially curing the protective film. For example, the peeling force can be reduced by partially curing the energy ray curable component (B).

[0139] Furthermore, the peeling forces F1 and F2 can also be controlled by the peeling treatment of the heavy-side release film 12 and the light-side release film 13. They can also be controlled by the manufacturing process of the energy-ray curable protective film forming sheet. This will be discussed later.

[0140] In a preferred embodiment, the polished surface of a silicon wafer polished to #6000 grit is attached to the protective film forming film, and the adhesive force between the silicon wafer and the protective film forming film before irradiating the protective film forming film with energy rays is preferably 500 mN / 25 mm or more and 3000 mN / 25 mm or less.

[0141] As mentioned above, the adhesive strength between the silicon wafer and the protective film can be controlled by the types and amounts of each component that make up the protective film.

[0142] Adhesion tends to increase when the weight-average molecular weight of polymer component (A) is low. Adhesion also tends to increase when the glass transition temperature of polymer component (A) is low. Furthermore, adhesion tends to increase when a low molecular weight compound is used as the energy-ray curable component (B). Adhesion tends to decrease when the amount of filler (C) is high.

[0143] Furthermore, similar to controlling the Young's modulus, the adhesive strength of the protective film can also be controlled by using, in combination, an energy-ray curable component (B) consisting of a urethane oligomer (b1) having a (meth)acryloyl group and an energy-ray curable low molecular weight compound (b2) having the aforementioned polar group. When these components are used together, the polar group forms a pseudo-crosslinked structure in the protective film, making it easier to reduce the adhesive strength of the protective film.

[0144] The adhesive strength can also be controlled by partially curing the protective film. For example, the adhesive strength can be reduced by partially curing the energy ray curable component (B).

[0145] In a preferred embodiment, the polished surface of a silicon wafer polished to #6000 grit is attached to the protective film-forming film, and after irradiating the protective film-forming film with energy rays to form a protective film, the peeling force of the protective film from the silicon wafer is preferably 3.0 N / 10 mm or more.

[0146] As mentioned above, the peeling force between the silicon wafer and the protective film can be controlled by the types and amounts of each component that make up the protective film-forming film.

[0147] A higher concentration of the energy-ray-curable component (B) strengthens the protective film, increasing the peeling force between the silicon wafer and the protective film. Furthermore, incorporating a silane coupling agent into the protective film-forming film can also increase the peeling force between the silicon wafer and the protective film.

[0148] In a preferred embodiment, the absorption rate of the protective film at a wavelength of 532 nm is preferably 70% to 95%.

[0149] As mentioned above, the light absorption rate of the protective film can be controlled by the types and amounts of each component that make up the protective film, and specifically by the types and amounts of colorants used.

[0150] (2. Sheet for forming energy ray-curable protective film) Before use, the protective film-forming film is stored in the form of an energy-ray curable protective film-forming sheet 10 with a three-layer structure, as shown in Figure 1, in which the protective film-forming film 11 is sandwiched between two release films (heavy-side release film 12, light-side release film 13). The release films are peeled off when the protective film-forming film is to be used. The above energy-ray curable protective film-forming sheet is usually in long lengths and is stored and transported wound into rolls without pre-cutting. Therefore, it is possible to prevent the protective film-forming film from being damaged by winding during storage and transport.

[0151] Heavy-duty release films and light-duty release films may consist of one layer (single layer) or two or more layers of substrate, or the surface of the substrate may be subjected to a release treatment from the viewpoint of controlling release properties. That is, the surface of the substrate may be modified, or a layer of a different material from the substrate may be formed on the surface of the substrate. In this embodiment, it is preferable that the heavy-duty release film and light-duty release film have a substrate and a release agent layer. By having a release agent layer, it is easier to control the physical properties of the surface on which the release agent layer is formed in the heavy-duty release film and light-duty release film. In this embodiment, a coating agent containing the release agent layer composition described later is applied to one surface of the substrate, and then the coating film is dried and cured to form the release agent layer. This gives rise to heavy-duty release films and light-duty release films.

[0152] (2.1 Heavy-duty release film 12) The thickness of the heavy surface release film 12 is not particularly limited, but is preferably 30 to 100 μm, more preferably 40 to 80 μm, and more preferably 45 to 70 μm, and is preferably thicker than the thickness of the light surface release film 13 described later.

[0153] By having the thickness of the heavy-duty release film 12 within the above range, cutting of the heavy-duty release film is prevented when the energy-ray curable protective film forming sheet is punched out to match the workpiece shape, and subsequent handling is also improved.

[0154] Note that the thickness of the heavy-duty release film 12 refers to the total thickness of the heavy-duty release film. For example, the thickness of a heavy-duty release film composed of multiple layers refers to the total thickness of all the layers that make up the heavy-duty release film.

[0155] Examples of substrates for the heavy-duty release film 12 include resin films and paper. Examples of resins for the resin film include polyethylene terephthalate, polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polybutylene terephthalate, polyurethane, ethylene-vinyl acetate copolymer, ionomer resin, ethylene (meth)acrylic acid copolymer, polystyrene, polycarbonate, fluororesin, low-density polyethylene, linear low-density polyethylene, and triacetylcellulose. Examples of paper include fine paper, coated paper, glassine paper, and laminated paper. These may be used individually or in combination of two or more. Among these, polyethylene terephthalate film is preferred from the viewpoint of being inexpensive and rigid.

[0156] At least one side of the heavy-sided release film 12 (the side laminated with the protective film-forming film 11) may be treated with a release agent layer composition. The thickness of the release agent layer is preferably 30 nm to 200 nm, and more preferably 50 nm to 180 nm.

[0157] The heavy-sided release film 12 can be easily obtained by peeling one side of the substrate described above. The release agent layer composition used in such peeling treatment is preferably an alkyd-based release agent, a silicone-based release agent, a fluorine-based release agent, an unsaturated polyester-based release agent, a polyolefin-based release agent, or a wax-based release agent, among which a silicone-based release agent is preferred, and it is particularly preferable to include a silicone-based release agent and a heavy-sided release additive.

[0158] As a silicone-based mold release agent, a silicone mold release agent containing a silicone having dimethylpolysiloxane as its basic structure can be used.

[0159] The silicone may be of the addition reaction type, condensation reaction type, or energy ray curing type such as ultraviolet curing type or electron beam curing type, but an addition reaction type silicone is preferred. Addition reaction type silicones have high reactivity and excellent productivity, and compared to condensation reaction type silicones, they have advantages such as less change in peel strength after manufacturing and no curing shrinkage.

[0160] Specific examples of addition-type silicones include organopolysiloxanes, which have two or more C2-C10 alkenyl groups, such as vinyl groups, allyl groups, propenyl groups, and hexenyl groups, at the ends and / or side chains of the molecule.

[0161] The content of dimethylpolysiloxane-based silicone in the release agent layer composition (excluding the catalyst described later), when the total weight is 100 parts by mass, is preferably less than 100 parts by mass, more preferably less than 90 parts by mass, more preferably less than 80 parts by mass, and particularly preferably less than 70 parts by mass.

[0162] When using such addition-reaction type silicones, it is preferable to use a crosslinking agent and a catalyst in combination.

[0163] Examples of crosslinking agents include organopolysiloxanes, which have at least two hydrogen atoms bonded to silicon atoms in one molecule.

[0164] Specific examples of crosslinking agents include dimethylhydrogensiloxy group-ended dimethylsiloxane-methylhydrogensiloxane copolymer, trimethylsiloxy group-ended dimethylsiloxane-methylhydrogensiloxane copolymer, trimethylsiloxy group-ended methylhydrogenpolysiloxane, and poly(hydrogensilsesquioxane).

[0165] Examples of catalysts include particulate platinum, particulate platinum adsorbed on a carbon powder support, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, palladium, and platinum group metal compounds such as rhodium.

[0166] By using such a catalyst, the curing reaction of the release agent layer composition can be made to proceed more efficiently.

[0167] The content of the silicone-based release agent when the total weight of the release agent layer composition (excluding the catalyst) is 100 parts by mass is preferably 30 to 100 parts by mass, and more preferably 50 to 100 parts by mass, from the viewpoint of keeping the release force F1 within an appropriate range.

[0168] Heavy release additives are used to increase the peel force F1 of the heavy release film 12 from the protective film forming film 11. Examples of heavy release additives include silicone resins and organosilanes such as silane coupling agents, but among these, silicone resin is preferred.

[0169] Examples of silicone resins include monofunctional siloxane units [R3SiO 1 / 2 The M unit is [SiO], and the tetrafunctional siloxane unit is [SiO]. 4 / 2 It is preferable to use MQ resin containing Q units, which are ]. The three Rs in the M unit each independently represent a hydrogen atom, a hydroxyl group, or an organic group. From the viewpoint of easily suppressing silicone migration, it is preferable that one or more of the three Rs in the M unit be a hydroxyl group or a vinyl group, and more preferably a vinyl group.

[0170] The content of the heavy peeling additive when the total weight of the peeling agent layer composition (excluding the catalyst) is 100 parts by mass is preferably 0 to 50 parts by mass, more preferably 5 to 45 parts by mass, and particularly preferably 10 to 40 parts by mass.

[0171] From the viewpoint of adjusting viscosity and improving applicability to the substrate, the release agent layer composition is preferably used as a coating agent containing a diluent solvent together with the various active ingredients described above. In this specification, "active ingredient" refers to the components contained in the coating agent containing the target composition, excluding the diluent solvent.

[0172] Examples of diluent solvents include aromatic hydrocarbons such as toluene, fatty acid esters such as ethyl acetate, ketones such as methyl ethyl ketone, and organic solvents such as aliphatic hydrocarbons such as hexane and heptane. These diluent solvents may be used individually or in combination of two or more.

[0173] The concentration of the active ingredient (solid content) in the coating agent containing the release agent layer composition is preferably 0.3 to 10% by mass, more preferably 0.5 to 5% by mass, and more preferably 0.5 to 3% by mass.

[0174] The release agent layer composition may contain additives commonly used in release agent layers, to the extent that they do not impair the effects of the present invention. Examples of such additives include pigments, dyes, and dispersants.

[0175] (2.2 Light surface release film 13) The thickness of the light release film 13 is not particularly limited, but from the viewpoint of facilitating peeling, it is preferably less than or equal to the thickness of the heavy release film 12, and more preferably thinner than the heavy release film 12. Therefore, the thickness of the light release film 13 is preferably 10 to 75 μm, more preferably 18 to 60 μm, and more preferably 24 to 45 μm.

[0176] The substrate used for the light-surface release film 13 is the same material as that used for the heavy-surface release film 12. The release agent layer composition for the light-surface release film 13 can be selected from the materials exemplified for the heavy-surface release film 12, as long as the relationship between F1 and F2 described above is satisfied. However, when controlling the release force by the composition of the release agent layer composition, it is preferable that the materials exemplified as heavy-surface release additives are present in a smaller amount than in the heavy-surface release film 12, or not present at all.

[0177] Furthermore, since the peeling force can be kept low by adding silicone oil to the release agent layer composition, silicone oil may be used to adjust the peeling force.

[0178] (2.3 Control of peeling force in release films) The peeling forces F1 and F2 are controlled by various factors in addition to the composition of the protective film-forming film described above. • Types of resin materials that make up the main components of the release agent layer composition (silicone-based, fluorine-based, long-chain alkyl-based, etc.) • Molecular weight of the resin material that forms the main component of the release agent layer composition • Crosslinking density of the release agent layer composition (This crosslinking density is also influenced by the type of crosslinking agent, its content before the crosslinking reaction proceeds, and the density of functional groups that react with the crosslinking agent.) • Additive components contained in the release agent layer composition (specifically, low molecular weight substances that do not crosslink and / or are poorly crosslinked are examples). • Thickness of the release agent layer • Surface roughness of the bonding surface between the release agent layer and the protective film forming film. • Thickness of the resin film used as the base material • Temperature when bonding the release film and the protective film-forming film • Pressure during lamination between release film and protective film-forming film • Roller speed when bonding the release film and the protective film-forming film.

[0179] When the resin film used as the base material is thin, it can be peeled with a small peeling force, while the peeling force tends to increase as the film is thicker. When one side of the release film is roughened and a protective film is formed on the roughened side, the peeling force of the release film tends to increase. Furthermore, when a coating agent containing the protective film-forming film composition described later is applied to the first release film, dried as necessary, and then the second release film is laminated, the peeling force of the first release film tends to increase, while the peeling force of the second release film tends to decrease.

[0180] By smoothing the bonding surface of the release film with the protective film-forming film, heavy-sided release films and light-sided release films can be obtained by formulating the release agent layer composition with relatively little influence from the manufacturing process described above. When controlling the release force of the heavy-sided release film by formulating the release agent layer composition, the arithmetic mean height Sa of the contact surface of the heavy-sided release film with the protective film-forming film (the release treatment surface of the heavy-sided release film) is preferably 1 μm or less, more preferably 0.2 μm or less, even more preferably 0.1 μm or less, and particularly preferably less than 0.03 μm. The arithmetic mean height Sa of the release treatment surface of the heavy-sided release film 12 can be controlled by, for example, the film-forming method of the resin film that is the base material (specifically, the stretching method, the temperature and surface roughness of the cooling roll), the surface treatment of the base material after film formation, the thickness of the release agent layer, etc.

[0181] The arithmetical mean height of the surface is one of the surface roughness parameters defined in ISO 25178, and is the average of the absolute values ​​of peak height and valley depth on the measured surface. In this specification, the arithmetical mean height Sa is the surface roughness obtained by measuring a 1.0 mm × 1.0 mm rectangular area.

[0182] (3. Method for manufacturing sheets for forming energy ray-curable protective films) The method for manufacturing the protective film-forming film is not particularly limited. The film is manufactured using the above-described protective film-forming film composition, or a composition obtained by diluting the protective film-forming film composition with a solvent (these two compositions are referred to herein as "coating agent containing protective film-forming film composition"). Examples of diluting solvents include aromatic hydrocarbons such as toluene, fatty acid esters such as ethyl acetate, ketones such as methyl ethyl ketone, and organic solvents such as aliphatic hydrocarbons such as hexane and heptane. These diluting solvents may be used individually or in combination of two or more. The coating agent is prepared by mixing the components constituting the protective film-forming film composition by known methods.

[0183] The obtained coating agent is applied to the release surface of the heavy-surface release film 12 using a coating machine such as a roll coater, knife coater, roll knife coater, air knife coater, die coater, bar coater, gravure coater, or curtain coater, and dried as necessary. Then, the light-surface release film 13 is laminated onto the exposed surface of the protective film forming film 11 to obtain the energy-ray curable protective film forming sheet 10 according to this embodiment. The energy-ray curable protective film forming sheet 10 is preferably a roll body wound into a roll as a long sheet that has not yet been die-cut, with the width of the heavy-surface release film, the width of the protective film forming film, and the width of the light-surface release film being the same after cutting. The lamination order is not particularly limited, and the coating agent may be applied to the light-surface release film. Alternatively, the coating agent may be applied to another resin film, dried as necessary, and the resulting protective film forming film may be transferred to the heavy-surface release film or the light-surface release film. Furthermore, after lamination, these films may be heated and pressurized using a hot roller or the like. From the standpoint of ease of work during manufacturing, the heavy-sided release film 12 may be applied to the release surface and dried as necessary. After that, the process release film may be laminated onto the exposed surface of the protective film forming film 11, the process release film may be peeled off, and the light-sided release film 13 may be applied.

[0184] (4. Workpiece machining method) In the energy-ray curable protective film forming sheet 10 according to this embodiment, the protective film forming film 11 may be pre-cut into a predetermined shape. However, as will be explained below, it is preferable that the film is not pre-cut before the application process, but rather pre-cut to match the shape of the back surface of the workpiece immediately before application, and then the pre-cut protective film forming film is applied to the back surface of the workpiece without being wound into a roll. The latter method will be described in detail below.

[0185] First, as shown in Figure 1, prepare an energy ray curable protective film forming sheet 10 that has not been die-cut. Next, as shown in Figure 2(A), the protective film-forming film 11 is punched out in a closed shape that is substantially the same as the back surface of the workpiece to which it will be attached, and a notch 14 is made. At this time, the light surface release film 13 and the protective film-forming film 11 of the energy ray curable protective film-forming sheet 10 are punched out completely, but the heavy surface release film 12 is not punched out completely.

[0186] Next, as shown in Figure 2(B), the entire light-surface release film 13 is peeled off, and the unnecessary portion 11a of the protective film-forming film 11 other than the closed shape is peeled off, leaving the closed-shaped protective film-forming film (used portion) 11b on the heavy-surface release film 12. When removing the light-surface release film 13 from the protective film-forming film 11b, if the peeling force F1 is 100mN / 100mm or more and 200mN / 100mm or less, the peeling force F2 is 30mN / 100mm or more and 100mN / 100mm or less, and the difference in peeling forces (F1-F2) is 50mN / 100mm or more, the removal of the light-surface release film 13 becomes easy, and the used portion of the protective film-forming film 11b can be reliably left on the heavy-surface release film 12.

[0187] The light-surface release film 13 can be peeled off by attaching a long adhesive tape called a peeling tape to the light-surface release film 13, and then moving the adhesive tape with the light-surface release film attached in a direction away from the protective film forming film 11. Since the unwanted portion 11a is formed continuously on the heavy-surface release film 12, the unwanted portion 11a can be peeled off continuously by moving the tape in a direction away from the heavy-surface release film 12, starting from the edge of the unwanted portion 11a. The unwanted portion 11a is part of the protective film forming film 11 and has the predetermined Young's modulus mentioned above, so it can be peeled off continuously without tearing during the peeling process.

[0188] Next, as shown in Figure 2(C), the back surface of the workpiece 15 is attached to the protective film-forming film 11b remaining on the heavy-surface release film 12 to obtain a workpiece with a protective film-forming film. When attaching the protective film-forming film 11 to the workpiece 15, heat pressing may be performed. The workpiece 15 may be attached to the protective film-forming film 11 while its surface is held in a peelable manner on a support such as an adhesive sheet. That is, the surface of the workpiece 15 may be temporarily attached to an adhesive sheet, and then the back surface of the workpiece 15 may be attached to the protective film-forming film 11b. The adhesive sheet may be a back-grind tape, and after temporarily attaching the surface of the workpiece to the adhesive sheet, the back surface of the workpiece 15 may be polished (back-grinded) before attaching the back surface of the workpiece 15 to the protective film-forming film 11b. In this specification, "temporary attachment" means being held in a peelable manner.

[0189] Subsequently, the protective film-forming film 11b is irradiated with energy rays to harden it, resulting in a workpiece with a protective film. If the protective film-forming film is to be hardened before peeling off the heavy-surface release film 12, the energy rays should be irradiated from the side of the heavy-surface release film 12. If the protective film-forming film is to be hardened after peeling off the heavy-surface release film 12, it is preferable to irradiate it with energy rays in an inert atmosphere to prevent hardening failure due to oxygen. The hardening (energy ray irradiation) of the protective film-forming film 11b may be performed after the process of transferring the workpiece onto the dicing sheet, as described later, or after the individualization process. The illuminance of the energy rays during energy ray irradiation should be 60 to 320 mW / cm². 2 Preferably, the light intensity is 100-1000 mJ / cm². 2 It is preferable that this be the case.

[0190] In this embodiment, the protective film-forming film 11b is cured and protected by energy ray irradiation. Therefore, the workpiece 15 is hardly heated during curing. Consequently, even if the protective film-forming film 11 is cured while the workpiece 15 is supported on the adhesive sheet, the adhesive sheet is hardly heated, and there is little risk of the adhesive sheet fusing to other devices or the adhesive sheet becoming excessively attached to the workpiece. After that, if the adhesive sheet is temporarily attached to the workpiece 15, the adhesive sheet is peeled off from the workpiece 15. Note that the peeling off of the adhesive sheet may be performed after the step of transferring the workpiece onto the dicing sheet, which will be described later.

[0191] Finally, if necessary, the protective film-coated workpiece or the protective film-forming film-coated workpiece can be pieced to obtain multiple individual pieces of the protective film-coated workpiece or the protective film-forming film-coated workpiece.

[0192] The process of dicing a workpiece with a protective film or protective film-forming film involves transferring the workpiece onto a known dicing sheet, dicing the workpiece, and obtaining individual pieces of the workpiece with a protective film or protective film-forming film. Subsequently, the dicing sheet is expanded in the planar direction as needed, and the individual pieces of the workpiece with a protective film or protective film-forming film are picked up from the dicing sheet using a suction collet or the like. The picked-up individual pieces of the workpiece with a protective film or protective film-forming film may be transported to the next process, or they may be temporarily stored in a tray, tape, etc., and transported to the next process after a predetermined period.

[0193] Although embodiments of the present invention have been described above, the present invention is not limited in any way to the embodiments described above, and may be modified in various ways within the scope of the present invention. [Examples]

[0194] The invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0195] (Preparation of protective film-forming sheets) [Heavy-duty release film] [Coating agent containing a composition for the release agent layer] The following raw materials for the release agent layer composition were prepared. • A silicone-based mold release agent containing organopolysiloxanes with vinyl groups and organopolysiloxanes with hydrosilyl groups (manufactured by Toray Dow Corning Co., Ltd., BY24-561, solids content 30% by mass) • Dimethylpolysiloxane (weight-average molecular weight: 2000) (manufactured by Shin-Etsu Chemical Co., Ltd., X-62-1387, solids content 100% by mass) • MQ resin with vinyl groups as a heavy release additive (manufactured by Toray Dow Corning Co., Ltd., SD-7292, solids content 71% by mass) • Platinum (Pt) catalyst (manufactured by Toray Dow Corning Co., Ltd., SRX-212, solids content 100% by mass)

[0196] The above raw materials were added to a mixed solvent of toluene and methyl ethyl ketone (toluene / methyl ethyl ketone = 1 / 1 (mass ratio)) in the mixing ratio (on a solid content basis) shown in Table 1, and the total solid content was adjusted to 2% by mass to prepare a coating agent containing a release agent layer composition.

[0197] [Preparation of heavy-duty release film] A release agent layer was formed on a PET film (manufactured by Mitsubishi Chemical, product name: Diafoil® T-100, thickness: 50 μm) by applying a coating agent containing a release agent layer composition to a PET film (manufactured by Mitsubishi Chemical, product name: Diafoil® T-100, thickness: 50 μm) so that the film thickness after drying would be 0.15 μm, then heating and drying to produce a release agent layer on the PET film, thereby producing a heavy-surface release film A. [Table 1]

[0198] [Light surface release film] Lintec's "SP-PET381130 (thickness 38μm)" was used.

[0199] [Coating agent containing a composition for protective film formation] Each of the following components was mixed in the respective mixing ratios (based on solid content) shown in Table 2, and diluted with methyl ethyl ketone to a solid content concentration of 50% by mass, to prepare coating agents containing each protective film-forming composition.

[0200] (A) Polymer component A (meth)acrylic acid ester copolymer (weight-average molecular weight: 600,000, glass transition temperature: 2°C) obtained by copolymerizing 33 parts by mass of n-butyl acrylate, 27 parts by mass of methyl acrylate, 25 parts by mass of acryloyl morpholine, and 15 parts by mass of 2-hydroxyethyl acrylate.

[0201] (B) Energy ray curable component (b1) Energy ray curable oligomer (b1-1) Viscoat #1000LT (Dendrimer-type polyfunctional acrylate with acryloyl groups arranged on the surface, weight-average molecular weight approximately 2000, number of acryloyl groups per molecule approximately 14, manufactured by Osaka Organic Chemical Co., Ltd.) (b1-2) Quick cure 8100EA70 (a bifunctional UV-curable urethane prepolymer with an acrylamide structure introduced as a reactive group, weight-average molecular weight approximately 10,000, 2 acryloyl groups per molecule, manufactured by KJ Chemicals): a urethane oligomer having an amide group derived from an acrylamide group.

[0202] (b2) Energy ray curable low molecular weight compounds (b2-1)NK Ester A-9300-1CL (ε-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate, 3 acryloyl groups per molecule, manufactured by Shin Nakamura Chemical Industry Co., Ltd.) (b2-2) OGSOL GA-2800 (Epoxy acrylate monomer with a fluorene skeleton, 2 acryloyl groups per molecule, manufactured by Osaka Gas Chemical Co., Ltd.): Low molecular weight compound having an acryloyl group and a fluorene skeleton. (b2-3) Aronics M-215 (isocyanuric acid EO-modified diacrylate, number average molecular weight 369, 2 acryloyl groups per molecule, manufactured by Toagosei Co., Ltd.): Low molecular weight compound having acryloyl and hydroxyl groups.

[0203] (C) Filler SC2050-MB (Epoxy-modified spherical silica filler, manufactured by Admatex, average particle size 0.5 μm)

[0204] (D) Photopolymerization initiator (D1) Omnirad 127D (2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one, manufactured by IGM Resins) (D2) Omnirad 379EG (2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, manufactured by IGM Resins) (D3) Omnirad 651 (2,2-dimethoxy-2-phenylacetophenone, manufactured by IGM Resins)

[0205] (E) Colorants (E1)Spectrasense TM Black L 0086 (Perylene black-based organic pigment, manufactured by Sun Chemical Co., Ltd.) (E2) Paliogen Red Violet K5411 (Perylene violet-based organic pigment, manufactured by Sun Chemical Co., Ltd.) (E3) 6390 Black (Organic black pigment, manufactured by Dainichi Seika Kogyo Co., Ltd.) (E4) 6377 Black (organic black pigment, manufactured by Dainichi Seika Kogyo Co., Ltd.)

[0206] others UV absorber Tinuvin 479 (manufactured by BASF)

[0207] [Table 2]

[0208] The prepared protective film-forming composition was coated onto the surface of the release agent layer of the heavy-sided release film A, and dried at 100°C for 2 minutes to form a protective film-forming film with a thickness of 25 μm. Subsequently, the light-sided release film was attached onto the protective film-forming film to obtain a three-layer protective film-forming sheet with release films formed on both sides of the protective film-forming film. The attachment conditions were a temperature of 60°C, a pressure of 0.4 MPa, and a speed of 1 m / min. Next, the protective film-forming sheet was cut to a width of 208 mm and wound into a 50-meter roll. Protective film-forming sheets were prepared for each protective film-forming film composition, and these were designated as the protective film-forming sheets for Examples 1 to 6 and Comparative Examples 1 to 5.

[0209] The protective film-forming sheets obtained were used for the following measurements and evaluations. The results are shown in Table 3. [Young's modulus of protective film-forming film]

[0210] The obtained protective film-forming sheet was cut to a size of 15 mm x 50 mm, and the light-side release film and heavy-side release film were peeled off to prepare a sample of the protective film-forming film for measurement. The Young's modulus of the measurement sample was measured at room temperature (23°C) using the method described below.

[0211] In accordance with JIS K 7127, a precision universal testing machine (Shimadzu Corporation, device name "Autograph® AG-IS") was used to perform a tensile test with a chuck distance of 20 mm (i.e., 15 mm at both ends of the test sample were chuck portions (non-measurement portions)) at a tensile speed of 200 mm / min in an environment of 23°C and 50% relative humidity, and the Young's modulus (MPa) was measured.

[0212] [Peel force F1 from the protective film-forming film of heavy-duty release film] The light-surface release film was peeled off from the obtained protective film-forming sheet. A laminated sample was prepared by heat laminating (70°C, 1 m / min) the good-adhesion side of a 25 μm thick high-adhesion PET (Toyobo Co., Ltd., PET25A-4100) onto the surface of the protective film-forming film that was exposed by peeling. The laminated sample was cut into 100 mm wide strips to prepare a sample for measurement. The back of the heavy-surface release film of the measurement sample was fixed to a rigid support plate with double-sided tape.

[0213] Using a universal tensile testing machine (Shimadzu Corporation, product name "Autograph® AG-IS"), a laminate of protective film-forming film / good-adhesion PET was peeled from the heavy-sided release film at a peel angle of 180° and peel speed of 1 m / min in an environment of 23°C and 50% relative humidity, and the load at that time was measured. The measurement distance was 100 mm in total, and the average of the measurements taken in the 80 mm section (excluding the first 10 mm and the last 10 mm) was converted to the unit mN / 100 mm and defined as the peel force F1.

[0214] [Peel force F2 from the protective film-forming film of the light-surface release film] The obtained protective film-forming sheet was cut to a width of 100 mm to prepare a sample for measurement. The back of the heavy-sided release film of the measurement sample was fixed to a rigid support plate with double-sided tape.

[0215] Using a universal tensile testing machine (manufactured by Shimadzu Corporation, product name "Autograph® AG-IS"), a light-surface release film was peeled from the measurement sample, and the load at that time was measured under the same conditions as the measurement of F1, and this was defined as the peel force F2.

[0216] [Adhesive properties of uncured protective film] The light-side release film was peeled off the obtained protective film-forming sheet, and Lintec adhesive tape (product name PET50 PL Thin: acrylic adhesive layer / 50 μm PET substrate) was laminated to the surface of the protective film-forming film exposed by peeling at 23°C. A laminated sample consisting of PET substrate / acrylic adhesive layer / protective film-forming film / heavy-side release film was prepared. This laminated sample was cut into strips with a width of 25 mm and a length of 250 mm. All of these operations were carried out in an environment of 23°C.

[0217] A silicon wafer with a thickness of 600 μm and polished to #6000 grit was prepared. The heavy-sided release film of the laminated sample was peeled off, and the exposed surface of the protective film-forming film was attached to the polished surface of the silicon wafer at a pressure of 0.3 MPa using a laminator with the roll heated to 70°C.

[0218] Under conditions of 23°C, the material was left undisturbed without heating, and after 30 minutes (±0.5 minutes) had elapsed since application, the adhesive strength was measured by starting a 180° peel-off using the measurement method described below.

[0219] Measurement method: A universal tensile testing machine (manufactured by Shimadzu Corporation, product name "Autograph® AG-IS") was used to measure the tensile strength at a distance of 100 mm, with a peeling speed of 100 mm / min and a temperature of 23°C, in accordance with JIS Z0237:2009.

[0220] The average of the measurements taken over 80 mm of the measurement distance, excluding the first 10 mm and the last 10 mm, was defined as the "adhesion strength of the uncured protective film."

[0221] [Peelability characteristics of protective film] The light-surface release film was peeled off from the obtained protective film-forming sheet, and the polished surface of a 6-inch silicon wafer (350 μm thick, #6000 polished silicon wafer) was attached to the surface of the protective film-forming film exposed by peeling, under conditions of 70°C and 0.3 MPa, thereby creating a first laminate in which the heavy-surface release film, protective film-forming film, and wafer were stacked in this order.

[0222] After allowing the first laminate to stand still for 20 minutes, the heavy release film was peeled off, and the exposed surface of the protective film-forming film was irradiated at an illuminance of 220 mW / cm 2 , with a light quantity of 500 mJ / cm 2 with ultraviolet light in an inert atmosphere filled with nitrogen gas as the irradiation environment, thereby preparing a second laminate configured by laminating a protective film and a wafer in this order. Next, the protective film and the wafer were divided into quarters using a ceramic cutter to prepare a third laminate having a size of 1 / 4 of that of the second laminate.

[0223] A dicing tape ("ADWILL D-833W" manufactured by Lintec Corporation) was attached to the exposed surface of the protective film in the third laminate, and cuts were made in the protective film and the dicing tape in the shape of 10 mm-wide strips from the dicing tape side using a utility knife. Subsequently, a tensile test for peeling the dicing tape and the protective film off the wafer was carried out using a precision universal testing machine ("Autograph (registered trademark) AG-IS" manufactured by Shimadzu Corporation) under conditions of a peeling angle of 90°, a measurement temperature of 23°C, and a tensile speed of 50 mm / sec. The load at this time was measured and taken as the peel force between the cured protective film-forming film (protective film) and the silicon wafer (the peel force of the protective film from the silicon wafer).

[0224] [Light absorptivity of protective film] [Sample preparation] The light-release film was peeled from the obtained protective film-forming sheet, and the surface of the protective film-forming film exposed by peeling was irradiated at an illuminance of 220 mW / cm 2 , with a light quantity of 500 mJ / cm 2 with ultraviolet light in an inert atmosphere filled with nitrogen gas as the irradiation environment, thereby being cured to obtain a cured product (protective film). The single-layer cured product was obtained by removing the heavy release film from the cured product.

[0225] [Reflectance measurement] For the exposed surface of the cured material (the surface from which the heavy release film was removed), the total reflected light intensity, which is the sum of specular reflection and diffuse reflection, was measured at 1 nm intervals in the wavelength range of 380 to 800 nm using the SCI method. The total reflected light intensity was also measured for a barium sulfate reference plate using the same method as above. In all cases, the total reflected light intensity was measured using a UV-Vis spectrophotometer (Shimadzu Corporation "UV-VIS-NIR SPECTROPHOTOMETER UV-3600"). A Shimadzu Corporation "Large Sample Chamber MPC-3100" was used as the sample folder, and a Shimadzu Corporation "Integrating Sphere Attachment ISR-3100" was used as the integrating sphere, with the incident angle of light on the object being measured set to 8°. Then, the ratio of the measured value on the cured product to the measured value on the reference plate ([measured value of total light reflected light intensity of the protective film] / [measured value of total light reflected light intensity on the reference plate] × 100), i.e., the relative total light reflectance of the protective film, was determined. Of the obtained relative total light reflectances, the value in the 532 nm wavelength range was adopted as the reflectance of light (532 nm).

[0226] [Transmittance measurement] For the cured material, the transmittance of light was measured at 1 nm intervals in the wavelength range of 380 to 800 nm using a UV-Vis spectrophotometer (Shimadzu Corporation's "UV-VIS-NIR SPECTROPHOTOMETER UV-3600") and an integrating sphere (Shimadzu Corporation's "Integrating Sphere Attachment ISR-3100"). Of the obtained measurements, the value in the wavelength range of 532 nm was adopted as the transmittance of light (532 nm).

[0227] (Calculation of light absorption rate) Using the light (532nm) reflectance and light (532nm) transmittance values ​​of the protective film obtained above, the light (532nm) absorptance of the protective film was calculated according to the following formula (i). [Absorption rate of the protective film at 532nm (%)] = 100 - ([Reflectance rate of the protective film at 532nm (%)] + [Transmittance rate of the protective film at 532nm (%)]) (i)

[0228] [Process suitability of protective film-forming sheets] We evaluated whether the protective film-forming sheet could be reliably punched into the desired shape. (Die-cutting process and removal of unnecessary parts of protective film-forming sheet) Using a Lintec RAD-3600F / 12 die set for 200mm wafers, the die was inserted from the light-side release film side of the protective film formation sheet, and the protective film formation film and the light-side release film were punched out in a circular shape (inner diameter 198mm). During this process, cuts were made in the heavy-side release film to prevent complete punching (punching process). Five punching operations were performed. The average width of the cuts was 25μm.

[0229] After the punching process, the circular punched-out portion was left on the heavy-side release film, and the light-side release film and the unnecessary parts around the circular punched-out portion were removed (unnecessary part removal process). At this time, the light-side release film that had been punched out and completely cut was joined together again with a long piece of adhesive tape before the light-side release film was removed.

[0230] [Evaluation of process suitability] The extent of peeling of the unnecessary parts was checked, and the following criteria were used for evaluation. A: When removing the light-side release film, the protective film-forming film in the unnecessary portion peeled off from the heavy-side release film, and it was confirmed that the heavy-side release film and the circular protective film-forming film were integrated (indicating that the removal of the unnecessary portion was performed correctly). B: When removing the light-side release film, the protective film-forming film on the unnecessary parts did not peel off from the heavy-side release film (i.e., the protective film-forming film remained on the entire surface of the heavy-side release film). C: When removing the light-surface release film, a portion of the circular protective film-forming film may tear and remain attached to the light-surface release film (i.e., the circular protective film-forming film may not be obtained).

[0231] [Laser marking suitability of protective films] The suitability of the protective film for laser marking was evaluated by the visibility of the printed markings when the protective film was directly printed using a laser beam (wavelength 532 nm). Similar to the [peelability characteristics of the protective film] described above, a silicon wafer with a protective film (second laminate) was obtained. Using this silicon wafer with a protective film, laser printing was performed on the exposed side of the protective film (the side opposite to the silicon wafer side) using a green laser marker (EO tech "CSM300M") under the following conditions.

[0232] [Laser printing conditions] Laser light wavelength: 532nm Printed characters: ABCDEFGHI Printed character size: Height 75μm x Width 50μm Line width of printed characters: 20 μm Laser printing speed: 100 mm / second Laser frequency: 20kHz Laser output: 0.3W

[0233] Using an optical microscope (Keyence "Digital Microscope VHX-7000"), one observer observed the printing on the protective film formed as described above under the following conditions: white balance R=1.77, G=1.00, B=2.31, ring illumination, brightness 100, magnification 100x, and shutter speed 1 / 120 second. The visibility of the printed text was evaluated according to the following criteria.

[0234] A: The printing is clear, and all printed characters (A-I) are legible. B: The printing is generally clear, but partially unclear, with 7 to 8 of the 9 printed characters (A to I) being legible. C: The printing is unclear, and at least three of the nine printed characters (A-I) are illegible.

[0235] [Table 3] [Industrial applicability]

[0236] According to the present invention, when the protective film forming film is die-cut immediately before being attached to the workpiece, unnecessary portions can be reliably removed and a protective film forming film of the desired shape can be reliably formed. [Explanation of symbols]

[0237] 10…Sheet for forming energy ray-curable protective film 11…Protective film-forming film 12… Heavy-duty release film 13…Light surface release film 14...cut 15…Work

Claims

1. Energy ray curable protective film forming film for forming a protective film, A heavy-sided release film provided on one side of the energy-ray curable protective film forming film, The energy-curable protective film-forming film has a light-surface release film provided on the other side, The Young's modulus of the energy-curable protective film-forming film before energy ray irradiation is 6 MPa or more. The peel force F1 of the heavy-surface release film from the energy-curable protective film-forming film before energy ray irradiation is 100 mN / 100 mm or more and 200 mN / 100 mm or less. The peel force F2 of the light-surface release film from the energy-curable protective film-forming film before energy ray irradiation is 30 mN / 100 mm or more and 100 mN / 100 mm or less. The difference between the peeling force F1 and the peeling force F2 (F1-F2) is 50 mN / 100 mm or more and 160 mN / 100 mm or less. Sheet for forming energy ray-curable protective films.

2. The energy ray-curable protective film forming sheet according to claim 1, wherein the polished surface of a silicon wafer polished to #6000 is attached to the energy ray-curable protective film forming film, and the adhesive force between the silicon wafer and the energy ray-curable protective film forming film before irradiating the energy ray-curable protective film forming film with energy rays is 500 mN / 25 mm or more and 3000 mN / 25 mm or less.

3. The energy ray curable protective film forming sheet according to claim 1, wherein the polished surface of a silicon wafer polished to #6000 is attached to the energy ray curable protective film forming film, and the energy ray curable protective film forming film is irradiated with energy rays to form the energy ray curable protective film forming film into a protective film, and the peeling force of the protective film from the silicon wafer is 3.0 N / 10 mm or more.

4. The energy ray curable protective film forming sheet according to claim 1, wherein the protective film, after being irradiated with energy rays to form the energy ray curable protective film forming film, has an absorption rate of light with a wavelength of 532 nm of 70% or more and 95% or less.

5. An energy ray curable protective film forming sheet according to any one of claims 1 to 4, used for temporarily attaching a workpiece to an adhesive sheet, attaching the energy ray curable protective film forming film of the energy ray curable protective film forming sheet to the workpiece to form a workpiece with a protective film, irradiating the energy ray curable protective film forming film with energy rays to make the energy ray curable protective film forming film a protective film, and then peeling the adhesive sheet off the workpiece to manufacture a workpiece with a protective film.

6. The workpiece is temporarily attached to the adhesive sheet, The light-side release film and the energy-ray-curable protective film forming film of the energy-ray-curable protective film forming sheet according to any one of claims 1 to 4 are punched out into a closed shape substantially identical to the back surface of the workpiece, and notches are formed so as not to completely punch out the heavy-side release film. The light surface release film is completely removed, and any unnecessary portions of the energy ray-curable protective film forming film other than the closed shape are removed, leaving an energy ray-curable protective film forming film with a closed shape substantially identical to that of the back surface of the workpiece on the heavy surface release film. An energy-curable protective film-forming film having a closed shape substantially identical to the back surface of the workpiece is attached to the back surface of the workpiece to create a workpiece with a protective film-forming film. The energy ray-curable protective film-forming film is irradiated with energy rays to form a protective film. The adhesive sheet is peeled off from the workpiece. A method for manufacturing a workpiece with a protective coating.

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