Sheet for forming protective film and method for producing same

Abstract

The invention provides a sheet for forming a protective film and a method for manufacturing the same. Even if the notch width during punching is narrow, the defect of scrap removal can be sufficiently suppressed. The sheet for forming a protective film is a long sheet, has a protective film-forming film and a first release film provided on one surface of the protective film-forming film, and is characterized in that the adhesive force after two protective film-forming films are adhered for 2 minutes at 23 DEG C with a load of 2 kgf is 19 N / 25 mm or less.

Description

[0001] This invention is a divisional application of Chinese Patent Application No. 202110735474.0, filed on June 30, 2021, entitled “Sheet for forming a protective film and method of manufacturing the same”. This application claims priority to Japanese Patent Application No. 2020-136453, filed on August 12, 2020. Technical Field

[0002] This invention relates to a protective film forming sheet and a method for manufacturing the same. More particularly, it relates to a protective film forming sheet having a protective film forming film suitable for use in protecting semiconductor wafers or other workpieces, or in processing workpieces to obtain semiconductor chips or other processed products, and a method for manufacturing the protective film forming sheet. Background Technology

[0003] In recent years, semiconductor devices have been manufactured using a mounting method known as flip-chip bonding. In this method, when mounting a semiconductor chip with circuit surfaces having convex electrodes such as bumps, the circuit surface side of the semiconductor chip is flipped (face down) and bonded to a chip mount. Therefore, the semiconductor device has a structure where the back side of the semiconductor chip, where no circuitry is formed, is exposed.

[0004] Therefore, to protect semiconductor chips from impacts during handling, a hard protective film made of organic material is usually formed on the back side of the semiconductor chip. To form this protective film, an uncured resin film (hereinafter referred to as the "protective film forming film") is used as its precursor. The protective film forming film is attached to the back side of the semiconductor wafer and is diced together with the wafer to form a chip. By curing the protective film forming film, a chip with a protective film on the back side can be obtained.

[0005] As a product form that forms a protective film, known examples include... Figure 1 As shown, a protective film forming sheet 10 with a double-layer structure of protective film forming film 11 is laminated on the first release film 12 in a peelable manner, or as... Figure 3 The protective film forming sheet 20 shown is a three-layer structure in which a protective film forming film 11 is held between two release films (12, 13). Furthermore, the aforementioned protective film forming sheet is a long strip and is wound into a roll for storage and transportation. Sometimes, the protective film forming film of this type is pre-punched into a shape approximately the same as the workpiece (a general term for adhered objects such as semiconductor wafers) and then attached to the workpiece. This type of punched protective film forming sheet has a protective film forming film 16, punched into a predetermined closed shape, layered on the first release film 12. Figure 2 ), or sandwich it between two peeling films (12, 13) Figure 4 ).

[0006] The protective film forming sheet, which has undergone punching processing, is manufactured by punching the protective film forming film into a predetermined closed shape using a die, and is used by removing the unused portion 17 around the punched protective film forming film 16. When forming a protective film forming sheet with a double-layer structure consisting of a protective film forming film 11 and a first release film 12, a cut 14 is made such that the protective film forming film 11 is completely punched into a predetermined closed shape while the first release film 12 is not completely punched, and the protective film forming film 16 with the predetermined closed shape remains on the first release film 12, while the unused portion 17 around the periphery is removed. When forming a protective film 11 between two release films (12, 13) in a three-layer structure, a cut 14 is made such that the protective film forming film 11 and the second release film 13 on one side are completely punched into a specified closed shape, while the first release film 12 on the other side is not completely punched. The protective film forming film 16 with the specified closed shape remains on the first release film 12, and the peripheral useless parts 17 and the second release film 13 are removed.

[0007] The following is a further detailed explanation using the example of a sheet forming a double-layer protective film. For example... Figure 5 As shown, a protective film forming sheet 10, which is composed of a protective film forming film 11 and a first release film 12, is produced by cutting a notch 14 in a manner that completely punches the protective film forming film 11 into a predetermined closed shape and does not completely punch the first release film 12, thus producing a protective film forming sheet that has undergone punching processing. This process is called the "punching process".

[0008] Then, in order to attach the punched protective film forming sheet to the workpiece, the unused portion 17 around the periphery of the protective film forming film 16, which has been punched into a specified closed shape, is removed. Figure 6 This process is referred to as the "waste removal process". The result is a laminate having a protective film forming film 16 that is punched into a specified closed shape on the first release film 12 and can be used for attachment to the workpiece.

[0009] When forming a protective film with a three-layer structure, the process is the same as that for a protective film forming sheet with a two-layer structure, except that in the punching process, another release film 13 (second release film 13) is formed on the protective film forming film 11, and the second release film 13 is also completely punched into a specified closed shape, and the second release film 13 is removed in the waste removal process.

[0010] As a sheet for forming a protective film, it is required to be able to stably perform the punching process (operational stability). In particular, after punching the protective film forming film, the operational stability of the waste removal process for removing useless parts is required. More specifically, in the waste removal process, it is required that the problem of the protective film forming film 16 that should remain being accidentally peeled off from the first release film 12 along with the useless parts 17 should not occur (hereinafter referred to as "waste removal defect").

[0011] To address the aforementioned issues, for example, Patent Document 1 proposes controlling the peeling force between the release film and the protective film within a specified range.

[0012] Prior art literature

[0013] Patent Literature

[0014] Patent Document 1: International Publication WO2017 / 145735 Summary of the Invention

[0015] (a) Technical problems to be solved

[0016] If defects occur in waste removal, the production line must be stopped and defective products discarded, leading to decreased productivity and increased costs. Therefore, it is necessary to further control defects in waste removal.

[0017] The inventors of this invention have further and persistently studied the reasons for poor waste removal and have obtained the following insights.

[0018] After the punching process and before the waste removal process, the protective film forming sheet 10 passes through multiple rollers, such as guide rollers, for the purpose of controlling the tension of the protective film forming sheet. At this time, if... Figure 7 As shown, the protective film forming sheet 10 is sometimes bent such that the upper side of the cut 14 (the side into which the die enters) is the side of the roller 19. As a result of bending, the width of the cut 14 becomes narrower, especially in the cut portion that is almost parallel to the short side direction of the sheet 10, and the protective film forming film 16 is squeezed and slightly deformed. This is partly the reason why the adjacent protective film forming film 16 sometimes comes into contact with and adheres to the unused portion 17.

[0019] After passing through roller 19, in most cases the protective film forming film 16 and the attached portion of the useless part 17 will separate again, but sometimes they will remain attached without separating. If waste removal is performed with the protective film forming film 16 and the useless part 17 attached, the protective film forming film 16 that should remain on the first release film 12 will unexpectedly peel off from the first release film 12 along with the useless part 17 that should be removed, resulting in poor waste removal.

[0020] The present invention is made in view of the above-mentioned actual situation, and its object is to provide a protective film forming sheet that can effectively suppress the poor removal of waste material even when the kerf width is narrow during punching, and a method thereof for manufacturing the same.

[0021] (II) Technical Solution

[0022] The solution of the present invention is as follows.

[0023] (1) A protective film forming sheet, which is an elongated sheet and has a protective film forming film and a first release film disposed on one side of the protective film forming film, wherein,

[0024] The adhesion of the two protective films formed by attaching them to each other at 23°C with a load of 2 kgf for 2 minutes is less than 19 N / 25 mm.

[0025] (2) The protective film forming sheet according to (1), wherein the surface elastic modulus of the surface of the first peeling film in contact with the protective film forming film is 17 MPa or less.

[0026] (3) A protective film forming sheet according to (1) or (2), wherein a cut is formed on the protective film forming sheet such that a portion of the protective film forming sheet has a predetermined closed shape when viewed from above.

[0027] The cut extends through the protective film forming film in the thickness direction of the protective film forming sheet and reaches a portion of the first release film.

[0028] (4) The protective film forming sheet according to (3), wherein the width of the cut at the interface between the protective film forming film and the first release film is 8 μm or more.

[0029] (5) A method for manufacturing a protective film forming sheet by punching, comprising a step of forming a cut in a manner that gives a portion of the protective film forming sheet described in (1) or (2) above a predetermined closed shape.

[0030] The cut extends through the protective film forming film in the thickness direction of the protective film forming sheet and reaches a portion of the first release film.

[0031] (6) The method for manufacturing a protective film forming sheet by punching according to (5), wherein the width of the cut at the interface between the protective film forming film and the first release film is 8 μm or more.

[0032] (III) Beneficial Effects

[0033] According to the present invention, a protective film forming sheet and a method thereof are provided that can sufficiently suppress the poor removal of waste material even when the kerf width is narrow during punching. Attached Figure Description

[0034] Figure 1 A cross-sectional schematic diagram of the sheet used for forming the protective film in the implementation scheme.

[0035] Figure 2 This is a cross-sectional schematic diagram showing the state of the protective film forming sheet after punching.

[0036] Figure 3 A cross-sectional schematic diagram of a protective film forming sheet for another embodiment.

[0037] Figure 4 This is a cross-sectional schematic diagram showing the state of the protective film forming sheet after punching in another embodiment.

[0038] Figure 5 A schematic perspective view of the sheet used for forming a protective film after the punching process.

[0039] Figure 6 A perspective view illustrating the waste removal process.

[0040] Figure 7 This is a cross-sectional view showing the protective film forming sheet passing through a roller after the punching process.

[0041] Figure 8 This is a cross-sectional schematic diagram of an example of a chip having a protective film obtained by forming a protective film from the protective film of this embodiment.

[0042] Figure 9 This is a cross-sectional schematic diagram illustrating the process of attaching the protective film forming sheet of this embodiment onto a wafer.

[0043] Figure 10 This is a cross-sectional schematic diagram illustrating the process of singulation of a wafer with a protective film.

[0044] Figure 11 This is a cross-sectional schematic diagram illustrating the process of placing a chip with a protective film onto a substrate.

[0045] Explanation of reference numerals in the attached figures

[0046] 10: Protective film forming sheet (this embodiment); 11: Protective film forming film; 12: First release film; 13: Second release film; 14: Cut; 16: Protective film forming film after punching; 17: Unused portion; 19: Roller; 20: Protective film forming sheet (another embodiment); 21: Wafer; 22: Divider; 30: Chip with protective film; 31: Chip; 32: Protective film; 33: Convex electrode; 50: Substrate. Detailed Implementation

[0047] First, the main terms used in this specification will be explained.

[0048] The workpiece is a plate-shaped body to be processed, which is attached to the protective film formed in this embodiment. Examples of workpieces include wafers and panels. Specifically, examples include semiconductor wafers and semiconductor panels. Processed products of the workpiece include chips obtained by unitizing wafers. Specifically, an example is a semiconductor chip obtained by unitizing a semiconductor wafer. In this case, the protective film is formed on the back side of the wafer and the chip.

[0049] The "surface" of a workpiece such as a wafer refers to the surface on which circuits and convex electrodes such as bumps are formed, while the "back side" refers to the surface on which circuits and electrodes (such as bumps and convex electrodes) are not formed.

[0050] In this specification, for example, "(meth)acrylate" is used as a term to refer to both "acrylate" and "methacrylate", and other similar terms are used in the same way.

[0051] A release film is a film that supports a protective film in a peelable manner. The thickness of the film is not limited; it is used in the sense of a sheet.

[0052] The mass ratios in the descriptions of compositions for forming protective films and compositions for release agent layers are based on the active ingredient (solid component), and solvents are not included unless otherwise specified.

[0053] The present invention will now be described in detail in the following order, according to specific embodiments.

[0054] (1. Protective film formation)

[0055] like Figure 1 , Figure 5 As shown, the protective film forming sheet 10 of this embodiment is a long strip having a protective film forming film 11 and a first release film 12 disposed on one side of the protective film forming film 11, which is usually rolled up.

[0056] The protective film forming film 11 is formed by attaching it to the workpiece and applying a protective film to it, thereby forming a protective film for protecting the workpiece or the processed part of the workpiece.

[0057] "Protective film formation" refers to making the protective film forming film 11 into a state that has sufficient properties for protecting the workpiece or the processed product of the workpiece. Specifically, when the protective film forming film of this embodiment is curable, "protective film formation" means turning the uncured protective film forming film into a cured product. In other words, the protective film forming film after protective film formation is a cured product of the protective film forming film, which is different from the protective film forming film.

[0058] After the workpiece is stacked on the curable protective film, the protective film is cured, thereby firmly adhering the protective film to the workpiece and forming a durable protective film.

[0059] When the protective film forming film 11 is used in a non-cured state without containing curable components, it becomes protective when the protective film forming film of this embodiment is applied to the workpiece. In other words, the protective film can also be the same as the protective film forming film.

[0060] Where high protective performance is not required, the protective film can be non-curable since there is no need to cure the protective film.

[0061] In this embodiment, the protective film is preferably curable. Therefore, the protective film is preferably a cured product. Examples of cured products include thermosetting products and energy-cured products. In this embodiment, a thermosetting product is more preferably used for the protective film.

[0062] Furthermore, the protective film forming film preferably has adhesive properties at room temperature (23°C) or preferably develops adhesive properties through heating. This allows the workpiece and the protective film forming film to be bonded together when they are stacked. Therefore, positioning can be reliably achieved before the protective film forming film cures.

[0063] The protective film can consist of a single layer or multiple layers. When the protective film has multiple layers, these layers can be the same as each other or different from each other, and there is no particular limitation on the combination of the layers that make up these multiple layers.

[0064] In this embodiment, the protective film is preferably formed as a single layer. If the protective film is composed of multiple layers, there is a risk of interlayer delamination due to differences in the thermal expansion and contraction of the layers during processes involving temperature changes (such as reflow soldering or the use of the apparatus). A single layer can reduce this risk.

[0065] The thickness of the protective film is not particularly limited, but it is preferably 100 μm or less, more preferably 70 μm or less, even more preferably 45 μm or less, and particularly preferably 30 μm or less. If the thickness of the protective film is within the above range, even if the protective film formed after punching comes into contact with or adheres to the unused portion when passing through the roller after the punching process, it is easily separated again after passing through the roller. Furthermore, the thickness of the protective film is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. If the thickness of the protective film is within the above range, the protective performance of the obtained protective film becomes good.

[0066] In addition, the thickness of the protective film refers to the overall thickness of the protective film. For example, the thickness of a protective film consisting of multiple layers refers to the total thickness of all the layers that make up the protective film.

[0067] The following describes the protective film formed on the chip, which is the workpiece. Specifically, using... Figure 8 The chip 30 with a protective film shown here is an example of a protective film formed by applying a protective film to the protective film forming film of this embodiment.

[0068] like Figure 8 As shown, the chip 30 with a protective film is on the back side of the chip 31 (in... Figure 8 A protective film 32 is formed on the surface side of the chip 31 (the upper side). Figure 8 A convex electrode 33 is formed on the lower side (in the middle).

[0069] A circuit is formed on the surface side of the chip 31, and a raised electrode 33 is formed on this surface side in a manner that is electrically connected to the circuit. The chip 30 with a protective film is positioned such that the surface on which the raised electrode 33 is formed faces the chip mounting substrate. Then, through a predetermined heat treatment (reflow soldering process), it is electrically and mechanically connected to the substrate via the raised electrode 33, thereby achieving mounting. Examples of raised electrodes 33 include bumps, pillar electrodes, etc.

[0070] (1.1 Adhesion between protective film layers)

[0071] In this embodiment, by controlling the adhesion of the protective film forming films constituting the protective film forming sheet to be bonded together within a specified range, poor waste removal is suppressed. Specifically, this embodiment is characterized in that the adhesion after bonding two protective film forming films together for 2 minutes at 23°C with a load of 2 kgf is 19 N / 25 mm or less. This adhesion is preferably 15 N / 25 mm or less, more preferably 11 N / 25 mm or less. Furthermore, if the adhesion is too low, the retention performance of the workpiece may sometimes decrease, so the adhesion is preferably 0.1 N / 25 mm or more, more preferably 1 N / 25 mm or more, and particularly preferably 3 N / 25 mm or more. In addition, the reason for setting the adhesion measurement to be after bonding the protective film forming films together for 2 minutes is that in the apparatus for waste removal and workpiece bonding, during the process of the protective film forming sheet passing through the roller 19, the time for the cut portion to contact the roller 19 and stop is approximately 2 minutes.

[0072] As described above, by controlling the adhesion between the protective film forming films within a specified range, even if the protective film forming sheet is bent after the punching process, the punched protective film forming film 16 and the useless portion 17 will adhere to each other, and the protective film forming film 16 and the useless portion 17 can be separated again after the protective film forming sheet passes through the roller, thereby reducing the defects in waste removal.

[0073] (1.2 Composition for forming protective film)

[0074] The composition of the protective film forming film is not particularly limited as long as the protective film forming film possesses the aforementioned physical properties. In this embodiment, the composition constituting the protective film forming film (the composition for forming the protective film) is preferably a resin composition containing at least a polymer component (A), a curing component (B), and a filler material (E). The polymer component is considered to be a component formed by the polymerization reaction of a polymeric compound. Furthermore, the curing component is a component capable of undergoing a curing (polymerization) reaction. In addition, the polymerization reaction in this invention also includes a condensation polymerization reaction.

[0075] Furthermore, components contained in polymeric components are sometimes also curable components. In this embodiment, when the composition for forming a protective film contains such a component that is both a polymeric component and a curable component, it is considered that the composition for forming a protective film contains both a polymeric component and a curable component.

[0076] (1.2.1 Polymer composition)

[0077] The polymer component (A) imparts film-forming properties to the protective film and provides it with appropriate adhesion, ensuring that the protective film adheres reliably and uniformly to the workpiece. The weight-average molecular weight of the polymer component is typically in the range of 50,000 to 2,000,000, preferably in the range of 100,000 to 1,500,000, and particularly preferably in the range of 200,000 to 1,000,000. If the weight-average molecular weight is too low, there is a tendency for increased adhesion between the protective film components. On the other hand, if the weight-average molecular weight is too high, compatibility with other components deteriorates, resulting in hindering the formation of a uniform film. Examples of such polymer components include acrylic resins, urethane resins, phenoxy resins, silicone resins, and saturated polyester resins; acrylic resins are particularly preferred.

[0078] Furthermore, unless otherwise specified in this specification, "weight-average molecular weight" refers to the converted value of polystyrene determined by gel permeation chromatography (GPC). As a determination performed by this method, for example, a high-performance GPC apparatus "HLC-8120GPC" manufactured by TOSOHCORPORATION, in which a high-performance chromatographic column "TSK gurdcolumn H" is sequentially connected, can be used. XL -H”, TSK Gel GMH XL "TSK Gel G2000 H" XL (All of the above are manufactured by TOSOH CORPORATION) The determination was carried out using a differential refractometer as the detector under the conditions of column temperature of 40℃ and injection rate of 1.0 mL / min.

[0079] Examples of acrylic resins include copolymers of (meth)acrylates composed of (meth)acrylate monomers and structural units derived from (meth)acrylate derivatives. Among these, alkyl (meth)acrylate monomers are preferably examples of alkyl (meth)acrylates with 1 to 18 carbon atoms in the alkyl group; specifically, examples include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and butyl (meth)acrylate. Furthermore, examples of (meth)acrylate derivatives include (meth)acrylate, glycidyl (meth)acrylate, and hydroxyethyl (meth)acrylate.

[0080] In this embodiment, glycidyl methacrylate or similar materials are preferably used to introduce glycidyl groups into the acrylic resin. The addition of glycidyl groups to the acrylic resin increases its compatibility with the epoxy resin (described later as a thermosetting component), resulting in a higher glass transition temperature (Tg) and improved heat resistance after the protective film is cured. Furthermore, in this embodiment, to control the adhesion or stickiness to the workpiece, hydroxyethyl acrylate or similar materials are preferably used to introduce hydroxyl groups into the acrylic resin.

[0081] The glass transition temperature of the acrylic resin is preferably -70°C to 40°C, more preferably -35°C to 35°C, more preferably -20°C to 30°C, even 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 flowability of the protective film during formation and heating can be suppressed, thus making it easier to obtain a smooth protective film. If the glass transition temperature is too low, there is a tendency for the adhesion between the protective film layers to increase. If the glass transition temperature is too high, the compatibility with other components deteriorates, which will hinder the formation of a uniform film.

[0082] When an acrylic resin has m types of structural units (m being an integer greater than or equal to 2), the glass transition temperature of the acrylic resin can be calculated as follows. That is, for each of the m monomers that derives the structural units in the acrylic resin, if each monomer is assigned a non-repeating number from 1 to m and named "monomer m", the glass transition temperature (Tg) of the acrylic resin can be calculated using the Fox formula shown below.

[0083] [Mathematical formula 1]

[0084]

[0085] In the formula, Tg is the glass transition temperature of acrylic resin, m is an integer greater than or equal to 2, Tgk is the glass transition temperature of the homopolymer of monomer m, Wk is the mass fraction of structural unit m derived from monomer m in acrylic resin, and Wk satisfies the following formula.

[0086] [Mathematical Expression 2]

[0087]

[0088] In the formula, m and Wk are the same as those mentioned above.

[0089] The Tgk value can be found in polymer datasheets, adhesive datasheets, or polymer handbooks. 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, and the Tgk of 2-ethylhexyl acrylate is -70°C.

[0090] When the total weight of the composition for forming the protective film is set to 100 parts by mass, the content of the polymer component 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, further preferably 14 to 50 parts by mass, and particularly preferably 15 to 45 parts by mass. By keeping the content of the polymer component within the above range, the amount of the low molecular weight component that increases the adhesion between the protective film-forming films can be limited to a suitable range, thus making the material design of the composition for forming the protective film easier.

[0091] (1.2.2 Thermosetting components)

[0092] The curing component (B) cures the protective film forming film, thereby forming a hard protective film. The curing component can be a thermosetting component, an energy-curing component, or a mixture thereof. When cured by irradiation with energy rays, the light transmittance of the protective film forming film in this embodiment decreases due to the presence of fillers and colorants described later. Therefore, for example, when the thickness of the protective film forming film increases, energy-ray curing can easily become insufficient.

[0093] On the other hand, even if the thickness of the thermosetting protective film increases, it can still be fully cured by heating, thus forming a protective film with high protective performance. Furthermore, by using conventional heating equipment such as a heating oven, multiple protective films can be heated at once to form a film, causing it to thermally cure.

[0094] Therefore, in this embodiment, the curing component is preferably thermosetting. That is, the protective film forming film of this embodiment is preferably thermosetting.

[0095] The following method can be used to determine whether a protective film is thermosetting. First, heat the protective film formed at room temperature (23°C) to a temperature higher than room temperature, and then cool it back to room temperature, thus forming a heated and cooled protective film. Next, at the same temperature, compare the hardness of the heated and cooled protective film with the hardness of the protective film formed before heating. If the heated and cooled protective film is harder, it is determined that the protective film is thermosetting.

[0096] As thermosetting components, epoxy resins, thermosetting polyimide resins, unsaturated polyester resins, and mixtures thereof are preferred, for example. Furthermore, thermosetting polyimide resins refer to a general term for low molecular weight, low-viscosity monomers or precursor polymers that form polyimide resins through thermosetting. Non-limiting specific examples of thermosetting polyimide resins are described, for example, in the Journal of the China Fiber Society, "Fibers and Industry," Vol. 50, No. 3 (1994), pp. 106-118.

[0097] The epoxy resin, as a thermosetting component, has the property of forming a three-dimensional network and a strong coating when heated. Various known epoxy resins can be used as such an epoxy resin. In this embodiment, the molecular weight (formula weight) of the epoxy resin is preferably 300 or more and less than 50,000, 300 or more and less than 10,000, 300 or more and less than 5,000, or 300 or more and less than 3,000. Furthermore, the epoxy equivalent of the epoxy resin is preferably 50 to 5,000 g / eq, more preferably 100 to 2,000 g / eq, and even more preferably 150 to 1,000 g / eq.

[0098] Specifically, examples of such epoxy resins include glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenol novolak, and cresol novolak; glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; glycidyl ethers of carboxylic acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; glycidyl- or alkyl-glycidyl-type epoxy resins formed by replacing the active hydrogen bonded to the nitrogen atom with glycidyl groups in aniline isocyanurate, etc.; and so-called alicyclic epoxides, such as vinylcyclohexane diepoxide, 3,4-epoxycyclohexylmethyl-3,4-dicyclohexane carboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-me-dioxane, which introduce epoxy groups into the carbon-carbon double bond within the molecule, for example, through oxidation. In addition, epoxy resins with biphenyl backbone, dicyclohexadiene backbone, naphthalene backbone, etc. can also be used.

[0099] When a thermosetting component is used as the curing component (B), it is preferable to use a curing agent (C) as an additive. For epoxy resins, a thermoactive latent epoxy resin curing agent is preferred. A "thermally active latent epoxy resin curing agent" is a type of curing agent that is difficult to react with epoxy resin at room temperature (23°C), but is activated by heating to a certain temperature, thereby reacting with the epoxy resin. Methods for activating thermoactive latent epoxy resin curing agents include methods that generate active species (anions, cations) in a heating-based chemical reaction; methods that are stably dispersed in epoxy resin near room temperature, but are compatible with epoxy resin, dissolve, and initiate a curing reaction at high temperatures; methods that utilize molecular sieve-encapsulated curing agents to dissolve at high temperatures and initiate a curing reaction; and microencapsulation-based methods, etc.

[0100] In the illustrated methods, it is preferable to use a method that stably disperses the epoxy resin at around room temperature, but is compatible with the epoxy resin, dissolves and initiates a curing reaction at high temperature.

[0101] Specific examples of thermally active latent epoxy resin curing agents include various onium salts, dicarboxylic acid dihydrazide compounds, dicyandiamine, amine adduct curing agents, imidazole compounds, and other high-melting-point active hydrogen compounds. These thermally active latent epoxy resin curing agents can be used alone or in combination of two or more. In this embodiment, dicyandiamine is particularly preferred.

[0102] Furthermore, phenolic resins are preferred as curing agents for epoxy resins. As phenolic resins, condensates of phenols and aldehydes, such as alkylphenols, polyphenols, and naphthols, can be used without particular restriction. Specifically, phenolic varnish resins, o-cresol varnish resins, p-cresol varnish resins, tert-butylphenol varnish resins, dicyclopentadiene cresol resins, poly(p-vinyl) phenolic resins, bisphenol A type phenolic varnish resins, or modified versions thereof can be used.

[0103] The phenolic hydroxyl groups contained in these phenolic resins can easily undergo an addition reaction with the epoxy groups of the aforementioned epoxy resins upon heating, thereby forming a cured product with high impact resistance.

[0104] The content of curing agent (C) relative to 100 parts by weight of epoxy resin is preferably 0.01 to 30 parts by weight, more preferably 0.1 to 20 parts by weight, more preferably 0.2 to 15 parts by weight, and particularly preferably 0.3 to 10 parts by weight. By setting the content of curing agent (C) within the above range, the network structure of the protective film becomes dense, making it easier to obtain the performance of a protective film for protecting workpieces.

[0105] When dicyandiamine is used as the curing agent (C), it is preferable to further use a curing accelerator (D). As a curing accelerator, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole (imidazoliums in which one or more hydrogen atoms are replaced by groups other than hydrogen atoms) are preferred. Among these, 2-phenyl-4-methyl-5-hydroxymethylimidazole is particularly preferred.

[0106] The content of the curing accelerator relative to 100 parts by weight of epoxy resin is preferably 0.01 to 30 parts by weight, more preferably 0.1 to 20 parts by weight, more preferably 0.2 to 15 parts by weight, and particularly preferably 0.3 to 10 parts by weight. By setting the content of the curing accelerator (D) within the above range, the network structure of the protective film becomes dense, thus easily obtaining the performance of protecting the workpiece as a protective film.

[0107] When the total weight of the composition for forming the protective film is set to 100 parts by mass, the total content of the thermosetting component and the curing agent is preferably 3 to 80 parts by mass, more preferably 5 to 60 parts by mass, more preferably 7 to 50 parts by mass, even more preferably 9 to 40 parts by mass, and particularly preferably 10 to 30 parts by mass. If the thermosetting component and the curing agent are combined in the above proportions, moderate tackiness can be exhibited before curing, allowing for stable application. Furthermore, after curing, the protective properties of the workpiece as a protective film are readily obtained.

[0108] If low molecular weight compounds are used as thermosetting components and curing agents, the viscosity of the protective film may increase, and the adhesion between the protective film components may also increase. Therefore, it is preferable to select the type and amount of thermosetting components and curing agents within the above-mentioned range in a way that controls the viscosity to an appropriate value.

[0109] (1.2.3 Energy-based components that can be solidified)

[0110] When the curing component (B) is an energy-curing component, the energy-curing component is preferably uncured, preferably adhesive, and more preferably uncured and adhesive.

[0111] Energy-curable components are components that are cured by irradiation with energy rays and are used to impart film-forming properties, flexibility, etc., to protective films.

[0112] As an energy-curing component, a compound having an energy-curing group is preferred, for example. Known energy-curing components can be cited as examples of such compounds.

[0113] When using low molecular weight compounds as curable components for energy rays, the viscosity of the protective film can sometimes increase, leading to greater adhesion between the films. Therefore, it is preferable to select the type and dosage of the energy ray curable component in a manner that controls the viscosity to an appropriate value.

[0114] (1.2.4 Filler Material)

[0115] By including a filler material (E) in the protective film forming film, the adjustment of the coefficient of thermal expansion of the resulting protective film becomes easier. By making this coefficient of thermal expansion close to that of the workpiece, the adhesion reliability of the encapsulation obtained using the protective film forming film is further increased. Furthermore, by including a filler material (E) in the protective film forming film, a rigid protective film can be obtained, further reducing the moisture absorption rate of the protective film and further increasing the adhesion reliability of the encapsulation.

[0116] The filler material (E) can be either organic or inorganic, but from the perspective of shape stability at high temperatures, inorganic filler material is preferred.

[0117] Preferred inorganic filler materials include, for example, powders of silica, alumina, talc, calcium carbonate, red iron oxide, silicon carbide, and boron nitride; beads obtained by spherizing these inorganic filler materials; surface-modified versions of these inorganic filler materials; single-crystal fibers of these inorganic filler materials; and glass fibers. Among these, silica and surface-modified silica are preferred. As for surface-modified silica, surface modification with a coupling agent is preferred, and surface modification with a silane coupling agent is more preferred.

[0118] The average particle size of the filler material is preferably 0.02~10μm, more preferably 0.05~5μm, and particularly preferably 0.10~3μm.

[0119] By setting the average particle size of the filler material to the above value, the operability of the composition for forming a protective film becomes good. Therefore, the quality of the composition for forming a protective film and the protective film formed is easily stabilized.

[0120] In addition, unless otherwise specified, “average particle size” in this specification refers to the particle size (D50) at the 50% cumulative value of the particle size distribution curve obtained by laser diffraction scattering.

[0121] When the total weight of the composition for forming the protective film is set to 100 parts by mass, the content of the filler material is preferably 15 to 80 parts by mass, more preferably 30 to 75 parts by mass, even more preferably 40 to 70 parts by mass, and particularly preferably 45 to 65 parts by mass.

[0122] By setting the filler content to the aforementioned values, it is easy to control the adhesion between the protective film and the film itself within an appropriate range. If the filler content is too low, the adhesiveness of the protective film increases, and the adhesion between the protective film and the film itself increases excessively. On the other hand, if the filler content is too high, the shape retention of the protective film may decrease, and the film may be unable to maintain its shape due to bending on the roller, resulting in an excessive decrease in the adhesiveness of the protective film and its adhesion to the workpiece.

[0123] Furthermore, the protective film forming film preferably contains two or more filler materials. That is, the filler material (E) is preferably a mixture of two or more filler materials. "Containing two or more filler materials" can mean containing two or more filler materials with different materials or two or more filler materials with different average particle sizes.

[0124] In this embodiment, it is preferable to include two or more filler materials with different average particle sizes. By including filler materials with different average particle sizes in the protective film forming film, it is easy to place filler materials with smaller average particle sizes in the gaps of filler materials with larger average particle sizes. As a result, the above-mentioned effects can be obtained, and it is easy to set the adhesion between the protective film forming films within the above-mentioned range.

[0125] When there are two or more fillers with different average particle sizes, it is preferable that the average particle size of the filler with the largest average particle size is 1.5 to 100 times that of the average particle size of the filler with the smallest average particle size, more preferably 2 to 20 times, and even more preferably 3 to 18 times.

[0126] In addition, it can be confirmed whether the protective film or the protective film forming film contains two or more filler materials with different average particle sizes by observing the cross-section of the protective film or the protective film forming film.

[0127] (1.2.5 Coupling agent)

[0128] The protective film forming film preferably contains a coupling agent (F). By including a coupling agent, the heat resistance of the protective film can be maintained after curing, and the adhesion between the protective film and the workpiece can be improved, while water resistance (damp heat resistance) can also be improved. As a coupling agent, silane coupling agents are preferred from the perspective of their versatility and cost advantages.

[0129] Examples of silane coupling agents include γ-glycidyl etheroxypropyltrimethoxysilane, γ-glycidyl etheroxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-(methacryloyloxypropyl)trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfide, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazole silane, etc. These silane coupling agents can be used alone, or two or more can be used in combination.

[0130] When the total weight of the composition for forming the protective film is set to 100 parts by mass, the content of the coupling agent 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.

[0131] (1.2.6 Colorants)

[0132] The protective film preferably contains a colorant (G). Therefore, since the back side of the processed workpiece, such as a chip, is covered, various electromagnetic waves generated within the electronic device can be shielded, reducing malfunctions in the processed workpiece. Furthermore, any defects in waste removal can be immediately detected by visual inspection.

[0133] As the colorant (G), known colorants such as inorganic pigments, organic pigments, and organic dyes can be used. In this embodiment, inorganic pigments are preferred.

[0134] Examples of inorganic pigments include carbon black, cobalt pigments, iron pigments, chromium pigments, titanium pigments, vanadium pigments, zirconium pigments, molybdenum pigments, ruthenium pigments, platinum pigments, ITO (indium tin oxide) pigments, and ATO (antimony tin oxide) pigments. Carbon black is particularly preferred because it can block electromagnetic waves over a wide wavelength range.

[0135] The amount of colorant (especially carbon black) 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 20 μm, and the total weight of the composition for forming the protective film is set to 100 parts by mass, the content of the colorant 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.

[0136] The average particle size of the colorant (especially carbon black) is preferably 1 to 500 nm, particularly preferably 3 to 100 nm, and even more preferably 5 to 50 nm. If the average particle size of the colorant is within the above range, it is easy to control the light transmittance within the desired range.

[0137] (1.2.7 Other additives)

[0138] Without impairing the effects of the present invention, the protective film forming composition may contain, for example, photopolymerization initiators, crosslinking agents, plasticizers, antistatic agents, antioxidants, absorbents, tackifiers, release agents, etc., as other additives.

[0139] In this embodiment, the content of the release agent in the composition for forming the protective film is preferably less than a specified amount. In this embodiment, it is preferably less than 0.00099% by mass relative to the total mass of the protective film. If the content of the release agent is too high, there is a tendency for the adhesion reliability between the protective film and the workpiece to decrease. Examples of release agents include alkyd release agents, silicone release agents, fluorinated release agents, unsaturated polyester release agents, polyolefin release agents, and wax release agents.

[0140] (1.2.8 Control of the adhesion between protective film layers)

[0141] As described above, the feature of this embodiment is that by controlling the adhesion of the protective film forming films constituting the protective film forming sheet to each other within a specified range, the poor removal of waste material is suppressed.

[0142] The adhesion between protective film-forming films can be controlled by the types and amounts of the components constituting the protective film-forming films.

[0143] If the polymer component (A) has a low weight-average molecular weight, it tends to increase adhesion. If the polymer component (A) has a low glass transition temperature, it also tends to increase adhesion. Furthermore, using low molecular weight compounds as curing agents (B), curing agents (C), curing accelerators (D), or energy-based curing agents tends to increase adhesion. A high amount of filler (E) tends to decrease adhesion.

[0144] Adhesion can also be controlled by partially curing the protective film. For example, by partially curing the curing component (B), adhesion can be reduced. There is no particular limitation on the timing of partially curing the protective film; it can be done, for example, as long as it occurs before passing through roller 19 during the punching process of the protective film forming sheet. However, from the perspective of setting the peel forces F1 and F2 (described later) within an appropriate range, and from the perspective of adhesion to the workpiece, it is preferable that the protective film forming film is not partially cured as described in the embodiments described later.

[0145] (2. Sheet for forming protective film)

[0146] Before use, the protective film can be formed as follows: Figure 1 As shown, the protective sheet 10, which has a double-layer structure in which a peelable protective film is laminated on the first release film 12 to form a film 11, is wound up and stored. Alternatively, it can be stored as follows: Figure 3 As shown, a protective film forming sheet 20 with a three-layer structure, in which a protective film forming film 11 is sandwiched between two release films (first release film 12, second release film 13), is wound up and stored (another embodiment). The release film is peeled off when the protective film forming film is used.

[0147] The aforementioned protective film forming sheet is a long strip and is wound into a roll for storage and transportation. As such a protective film forming sheet, there is also a protective film forming sheet in which the protective film forming film has been pre-punched into a shape approximately the same as the workpiece. The protective film forming film 16, with its punched holes forming a predetermined closed shape, is laminated onto the first release film 12. Figure 2 ), or sandwiched between two peeling films (12, 13) Figure 4 ).

[0148] The first release film may consist of one (single) or two or more substrate layers. From the perspective of controlling peelability, the surface of the substrate may be subjected to a peeling treatment. That is, the surface of the substrate may be modified, or a material not derived from the substrate may be formed on the surface of the substrate. In this embodiment, the first release film preferably has a substrate and a release agent layer. By having a release agent layer, it is easy to control the physical properties of the surface in the first release film where the release agent layer is formed. In this embodiment, after coating a coating agent containing the release agent layer composition described later is applied to one surface of the substrate, the coating is dried and cured, thereby forming the release agent layer. The first release film is thus obtained.

[0149] The thickness of the first release film 12 is not particularly limited, but is preferably 30~100μm, more preferably 40~80μm, and even more preferably 45~70μm.

[0150] By setting the lower limit of the thickness of the first release film 12 to the aforementioned value, it is possible to prevent the cutting blade from penetrating and cutting through the first release film 12 when the protective film forming film is cut off using a cutting blade. Furthermore, after the protective film forming sheet 10 is unwound and the protective film forming film 11 is cut out, the protective film forming sheet 10 passes through guide rollers and other rollers in the apparatus before being transported to the next process. However, by setting the upper limit of the thickness of the first release film 12 to the aforementioned value, it is possible to prevent the protective film forming film 11 from peeling off from the first release film 12.

[0151] Furthermore, the thickness of the first release film 12 refers to the overall thickness of the first release film. For example, the thickness of the first release film, which is composed of multiple layers, refers to the total thickness of all the layers constituting the first release film.

[0152] Examples of substrates for the first release film 12 include resin films and paper. Examples of resins used in resin films 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, fluoropolymers, low-density polyethylene, linear low-density polyethylene, and triacetyl cellulose. Examples of paper include high-quality paper, coated paper, cellophane, and laminated paper. These substrates can be used individually or in combination. From the perspective of cost-effectiveness and rigidity, polyethylene terephthalate film is preferred.

[0153] At least one side of the first release film 12 (the side that forms a film layer with the protective film) has been peeled off by the release agent layer composition. The thickness of the release agent layer is preferably 30 nm or more and 200 nm or less, more preferably 50 nm or more and 180 nm or less.

[0154] The surface elastic modulus (23°C) of the surface of the first release film 12 in contact with the protective film forming film 11 is preferably 17 MPa or less, more preferably 14 MPa or less, more preferably 13 MPa or less, and particularly preferably 12 MPa or less. The surface elastic modulus is an indicator of the ease with which the surface can deform. By setting the surface elastic modulus of the surface of the first release film 12 in contact with the protective film forming film 11 within the above range, during the punching process, when the die is pressed and then pulled up, lifting (peeling of about 1-4 mm) between the protective film forming film 11 and the first release film 12 can be suppressed. This is because the surface of the first release film 12 is relatively soft, and even if there is compression based on the die and depressurization based on its separation, the surface of the first release film will follow the deformation of the protective film forming film. By suppressing the occurrence of lifting, the defects in waste removal can be further reduced. There is no particular limitation on the lower limit of the surface elastic modulus of the surface of the first peeling film 12 that is in contact with the protective film forming film 11. However, if the surface elastic modulus is too low, the peeling force may increase. Therefore, it is preferred to be 3 MPa or more, more preferably 4 MPa or more, and particularly preferably 5 MPa or more.

[0155] The surface elastic modulus of the surface of the first release film 12 in contact with the protective film forming film 11 at 23°C can be measured using an atomic force microscope equipped with a cantilever. Specifically, the surface of the first release film 12 in contact with the protective film forming film 11 is subjected to cantilever pressing and pulling to obtain a force curve. The obtained force curve is fitted based on the JKR theory to determine the elastic modulus, which is then used as the surface elastic modulus of this invention. Specific measurement methods will be described in detail in the embodiments described later.

[0156] In order to set the peel force F1 (described later) within an appropriate range and to set the surface elastic modulus of the first release film 12 within the aforementioned range, in this embodiment, the composition used as the release agent layer is preferably, for example, an alkyd release agent, a silicone release agent, a fluorinated release agent, an unsaturated polyester release agent, a polyolefin release agent, or a wax release agent, wherein a silicone release agent is preferred, and a silicone release agent containing a heavy-duty peeling additive is particularly preferred.

[0157] As a silicone-based mold release agent, a silicone mold release agent incorporating silicone with dimethyl polysiloxane as the basic framework can be used.

[0158] The silicone can be any of the addition reaction type, condensation reaction type, and energy-curing type such as ultraviolet curing and electron beam curing, but is preferably an addition reaction type silicone. Addition reaction type silicones have high reactivity, excellent productivity, and compared with condensation reaction type silicones, they have advantages such as less change in peel force after manufacturing and no curing shrinkage.

[0159] As a specific example of addition-reactive organosilicon, organopolysiloxanes with two or more alkenyl groups (such as vinyl, allyl, propenyl, and hexenyl) having 2 to 10 carbon atoms at the molecule's ends and / or side chains are listed. From the perspective of reducing surface elastic modulus, it is preferable for addition-reactive organosilicon to have fewer alkenyl groups.

[0160] When the total weight of the composition for the stripping agent layer (excluding the catalyst described later) is set to 100 parts by mass, the content of organosilicon composed of dimethylpolysiloxane 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.

[0161] When using this type of addition-reaction organosilicon, it is preferable to use both a crosslinking agent and a catalyst simultaneously.

[0162] Examples of crosslinking agents include organopolysiloxanes having at least two silicon atoms bonded to hydrogen atoms in one molecule. From the perspective of reducing the surface elastic modulus, it is preferable that the composition for the release agent layer contains a low content of crosslinking agent.

[0163] Specific examples of crosslinking agents include dimethylsiloxane-methylhydrosiloxane copolymers with dimethylhydrosiloxane-terminated ends, trimethylsiloxane-methylhydrosiloxane copolymers with trimethylsiloxane-terminated ends, trimethylsiloxane-methylhydropolysiloxanes with trimethylsiloxane-terminated ends, and poly(hydrosilsesquioxane).

[0164] Examples of catalysts include particulate platinum, particulate platinum adsorbed on a carbon powder support, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefinic complexes of chloroplatinic acid, and platinum group metal compounds such as palladium and rhodium.

[0165] By using this catalyst, the curing reaction of the composition for the release agent layer can be carried out more effectively.

[0166] From the perspective of setting the surface elastic modulus within the above-mentioned range and setting the peeling force F1 described later within an appropriate range, when the total weight of the release agent layer composition (excluding the catalyst) is set to 100 parts by mass, the content of the silicone release agent is preferably 30 to 100 parts by mass, and more preferably 50 to 100 parts by mass.

[0167] The heavy-release additive is used to increase the release force F1, which will be described later. Examples of heavy-release additives include silicone resins, silane coupling agents, and other organosilanes, with silicone resins being preferred.

[0168] As an organosilicon resin, MQ resin is preferred, which contains [R3SiO] as a monofunctional siloxane unit. 1 / 2 The M unit of ] and the tetrafunctional siloxane unit [SiO] 4 / 2The Q unit of the M unit. Furthermore, each of the three Rs in the M unit independently represents a hydrogen atom, a hydroxyl group, or an organic group. From the perspective of easily suppressing silicone transfer, one or more of the three Rs in the M unit are preferably hydroxyl or vinyl, more preferably vinyl. From the perspective of reducing the surface elastic modulus, it is preferable that the content of silicone resin (especially MQ resin) in the composition for the release agent layer is low.

[0169] When the total weight of the composition for the stripping agent layer (excluding the catalyst) is set to 100 parts by mass, the content of the heavy stripping additive 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.

[0170] From the perspective of adjusting viscosity and improving coatability to substrates, the release agent layer composition is preferably used as a coating agent that contains a diluent solvent in addition to the aforementioned active ingredients. In this specification, "active ingredient" refers to the component contained in the coating agent containing the target composition, excluding the diluent solvent.

[0171] Examples of diluents include aromatic hydrocarbons such as toluene, fatty acid esters such as ethyl acetate, ketones such as methyl ethyl ketone, and aliphatic hydrocarbons such as hexane and heptane. These diluents can be used individually or in combination.

[0172] The concentration of the active ingredient (solid component) in the coating agent containing the composition for the release agent layer is preferably 0.3 to 10% by mass, more preferably 0.5 to 5% by mass, and even more preferably 0.5 to 3% by mass.

[0173] Without impairing the effects of the present invention, the composition for the release agent layer may contain additives commonly used in release agent layers. Examples of such additives include dyes and dispersants.

[0174] In the protective film forming sheet 10 of this embodiment, it is preferable to punch the protective film forming film 11 into a predetermined shape. That is, it is preferable to form a cut 14 on the protective film forming sheet in such a way that a portion of the protective film forming sheet 10 has a predetermined closed shape when viewed from above. In addition, from the perspective of preventing the protective film forming film from overflowing from the workpiece when it is attached to the workpiece, it is preferable that the shape of the punched protective film forming film is smaller than the shape of the workpiece.

[0175] (3. Method for manufacturing a protective film sheet)

[0176] There are no particular limitations on the manufacturing method of the protective film forming film. The film can be manufactured using a coating agent containing the aforementioned protective film forming composition. The coating agent can be prepared by mixing the components constituting the protective film forming composition using known methods.

[0177] Using a coating machine such as a roller coater, doctor blade coater, roller knife coater, air knife coater, mold coater, bar coater, gravure coater, or curtain coater, the obtained coating agent is applied to the release surface of the first release film 12 and dried to obtain the protective film forming sheet 10 of this embodiment, which has a protective film forming film 11 on the first release film 12. Alternatively, the coating agent can be applied to other resin films and dried to transfer the resulting protective film forming film onto the first release film. To obtain the protective film forming sheet 20 of another embodiment, a second release film 13 is attached to the exposed surface of the protective film forming film 11 stacked with the first release film 12, resulting in a protective film forming sheet 20 that holds the protective film forming film 11 between two release films.

[0178] (4. Method for manufacturing a protective film sheet formed by punching)

[0179] A method for punching a protective film forming sheet 10 and obtaining a protective film forming film 16 with a predetermined closed shape punched on a first release film 12 will be described.

[0180] (4.1 Punching process)

[0181] First, prepare Figure 1 The protective film forming sheet 10 shown is not punched. Using a die (not shown), a cut 14 is made from the protective film forming film 11 side of the protective film forming sheet 10, penetrating the protective film forming film 11 and reaching a portion of the surface of the first release film 12. The operation of making a cut that reaches only a portion of the surface without completely cutting off the entire surface is called a half-cut. As a result, a cut 14 is formed on a portion of the surface of the protective film forming sheet 10 in a manner having a defined closed shape (see reference). Figure 2 , Figure 5 Here, when the protective film is transferred onto the semiconductor wafer, the defined closed shape is approximately the same as the shape of the wafer. That is, the cut 14 is formed in a manner that is approximately the same as the shape of the workpiece to which the protective film 11 is attached or the area where the protective film should be formed. This process is called a "punching process".

[0182] Through the punching process, the protective film forming film 11 is divided into a protective film forming film 16 punched into a predetermined closed shape, and a continuous unused portion 17 around it. Along the long side of the protective film forming sheet 10, the protective film forming film 16 punched into a predetermined closed shape is provided at multiple locations.

[0183] In the punching process, a known die may be used appropriately. The punching process is performed by partially cutting the protective film forming film 11 while not completely cutting the first peeling film 12.

[0184] like Figure 2 , Figure 4 As shown, the cross-sectional shape of the cut 14 is approximately wedge-shaped. The width of the cut 14 is wider on the upper surface side of the protective film forming film 11 into which the die enters, and narrows on the lower surface side (the interface between the protective film forming film 11 and the first release film 12). The width of the cut 14 is not particularly limited, but from the perspective of preventing the protective film forming film 16 after punching from contacting and adhering to the useless portion 17, or from the perspective of shortening the contact and adhesion time, the width D of the cut 14 on the lower surface of the protective film forming film 11 (i.e., the upper surface of the first release film 12) is preferably 8 μm or more, more preferably 10 μm or more, further preferably 15 μm or more, and particularly preferably 20 μm or more. As the width D, the protective film forming sheet can be cut along the thickness direction, and the width of the cut on the upper surface of the first release film 12 in the cross-section can be measured as the width D. The upper limit of the width D is not particularly limited, but considering the width of the cutting blade that can reliably cut the protective film forming film, it is generally 100 μm or less, preferably 80 μm or less, more preferably 60 μm or less, and even more preferably 40 μm or less. In order to form such a cut 14, it is preferable to use a die with a cutting blade having a wider blade width at the front end.

[0185] After the above-described process, a protective film forming sheet 10 with punching is obtained. A cut 14 is formed on the protective film forming sheet such that, when viewed from the upper surface of the protective film forming film 11, a portion of the protective film forming sheet 10 has a predetermined closed shape (e.g., a shape substantially the same as the planar shape of a semiconductor wafer), and the cut 14 extends to a portion of the first release film 12 in the thickness direction of the protective film forming sheet 10. That is, a cut is also formed on the surface of the first release film 12 that is in contact with the protective film forming film 11. By bringing a cutting blade to the first release film 12, the protective film forming film 11 can be completely cut off.

[0186] (4.2 Waste removal process)

[0187] After the punching process and before the waste removal process, the protective film forming sheet 10 passes through multiple rollers such as guide rollers for the purpose of controlling the tension of the protective film forming sheet.

[0188] like Figure 6As shown, in the waste removal process, a continuous useless portion 17 is peeled off from the first peeling film 12, leaving a perforated protective film forming film 16 on the first peeling film 12. The peeled useless portion 17 is wound onto a waste removal roller.

[0189] According to the protective film forming sheet 10 of this embodiment, since the protective film forming films have low adhesion to each other, even if the protective film forming film 16 that has undergone punching process comes into contact with and adheres to the useless part 17 when passing through the roller 19 after the punching process, the protective film forming film 16 and the useless part 17 can be separated again after passing through the roller. As a result, poor waste removal in the waste removal process can be suppressed.

[0190] The protective film formed by punching can be rolled into a roll for storage and transportation.

[0191] (5. Workpiece machining methods)

[0192] As an example of a processing method for a workpiece using a punched protective film forming sheet according to this embodiment, a manufacturing method for a packaged chip with a protective film obtained by processing a wafer with a protective film forming film attached thereto is described.

[0193] The manufacturing method of the apparatus according to this embodiment includes at least the following steps 1 to 9.

[0194] Process 1: The process of punching holes in the protective film forming sheet 10.

[0195] Process 2: The protective film sheet formed after punching passes between rollers.

[0196] Step 3: Step 3: Removing the useless portion 17 of the protective film forming sheet 10

[0197] Step 4: The process of attaching the protective film forming film 11 of the protective film forming sheet 10 to the back side of the wafer.

[0198] Step 5: Forming the applied protective film into a protective film.

[0199] Step 6: Step of peeling the first release film off the protective film or protective film forming film.

[0200] Step 7: The process of single-chipping a wafer with a protective film or protective film forming film on the back to obtain multiple chips with protective films or protective film forming films.

[0201] Step 8: The process of placing a chip with a protective film or a protective film formed on a substrate.

[0202] Step 9: The process of heating the chip with a protective film or a protective film formed thereon, which is disposed on the substrate, and the substrate.

[0203] Processes 1 through 3 are as described above. Process 5 can be performed before process 6 or after any of processes 6 through 9. That is, the process of forming the protective film can be performed at any stage after the protective film is attached to the wafer.

[0204] Referring to the accompanying drawings, the manufacturing method of the apparatus having the above-described steps 1 to 9 will be described.

[0205] Figure 2 , Figure 4 , Figure 5 The outline of step 1 is shown above. Figure 6 A general outline of step 3 is shown.

[0206] like Figure 9 As shown, a protective film forming film 11 of a protective film forming sheet 10 is attached to the back side of wafer 21 (step 4). Then, the attached protective film forming film 11 is coated to form a protective film 32 (step 5), resulting in a wafer with a protective film. When the protective film forming film 11 is thermosetting, it is simply heated at a specified temperature for an appropriate time. Furthermore, when the protective film forming film 11 is energy-curable, an energy-transmitting film is used as the first release film 12, and energy rays are incident from the side of the first release film 12.

[0207] Alternatively, the curing of the protective film forming film 11 can be performed after the cutting process described later, or the protective film forming film 11 can be cured after picking up the chip with the protective film forming film from the cutting die.

[0208] Then, the wafer 21 with the protective film is transferred onto a known dicing die 22, and the wafer 21 with the protective film is diced, as follows: Figure 10 As shown, a chip 31 with a protective film 32 (chip 30 with a protective film) is obtained (step 7). Then, the dicing die 22 is extended along the planar direction as needed, and the chip 30 with the protective film is picked up from the dicing die 22 using a suction nozzle (not shown) or the like.

[0209] The picked-up chip 30 with protective film can be moved to the next process, or it can be temporarily stored on a tray, tape, etc., and moved to the next process after a specified period.

[0210] like Figure 11As shown, the chip 30 with a protective film, which is being transported to the next process, is picked up by a nozzle and placed onto the substrate 50. The terminals on the substrate detach from the nozzle and are positioned at locations where protruding electrodes 33 (such as bumps) and pads (such as solder pads) can be connected (process 8). At this time, other chips, different from the chip 30 with the protective film, can also be mounted on the substrate 50. Therefore, multiple chips can be mounted on this substrate.

[0211] The chip with a protective film disposed at a specified position on the substrate is subjected to heat treatment (reflow soldering) (step 9). As for the reflow soldering conditions, for example, the maximum heating temperature is preferably 180~350°C and the reflow soldering time is 2~10 minutes.

[0212] During the reflow soldering process, the convex electrode 33 of the chip 30 with a protective film melts and is electrically and mechanically connected to the terminal portion on the substrate, and the chip 30 with the protective film is mounted on the substrate.

[0213] (6. Variations)

[0214] The above description of the embodiments of the present invention uses a protective film forming sheet with a double-layer structure having a protective film forming film 11 on the first release film 12 as an example. However, a second release film 13 may also be laminated on the exposed surface of the protective film forming film 11. That is, the protective film forming sheet may also be a protective film forming sheet 20 (see reference 1) that holds the protective film forming film 11 between the first release film 12 and the second release film 13. Figure 3 , Figure 4 At this point, the second release film 13 can be peeled off before the protective film forming film 11 is attached to the workpiece.

[0215] The material and preferred form of the protective film forming film 11 of the protective film forming sheet 20 are the same as those in the above embodiment, and the first peeling film 12 is also the same as those described in the above embodiment.

[0216] Furthermore, in this embodiment, in the protective film forming sheet 20, when the peeling force for peeling the first release film 12 from the protective film forming film 11 is set to F1, and the peeling force for peeling the second release film 13 from the protective film forming film 11 is set to F2, F1 and F2 preferably satisfy the relationship F1 > F2. By satisfying this relationship, when the second release film 13 is removed from the protective film forming sheet 20, the protective film forming film 16 that should remain will not be removed along with the second release film 13, and the protective film forming film 16 will easily remain on the first release film 12, which can further suppress poor waste removal.

[0217] Therefore, the first peeling film 12 is a heavy peeling film with strong peeling force, and the second peeling film 13 is a light peeling film with weak peeling force.

[0218] Furthermore, the peel force F1 is preferably 50 mN / 100 mm or more, more preferably 70 mN / 100 mm or more, more preferably 90 mN / 100 mm or more, even more preferably 110 mN / 100 mm or more, and particularly preferably 130 mN / 100 mm or more. By keeping F1 within the above range, accidental peeling between the protective film forming film 11 and the first peel film 12 can be suppressed.

[0219] The peeling force can be adjusted, for example, by the type of composition used for the release agent layer, the thickness of the release agent layer, etc. The second release film 13 is designed to have a lower peeling force than the first release film 12. When the second release film 13 has a release agent layer, there are no particular restrictions as long as the release agent layer is made of a material that imparts peeling properties. For example, the release agent layer of the second release film 13 can be the same as the release agent layer of the first release film 12, obtained by curing a release agent layer composition containing organosilicon.

[0220] The composition for the release agent layer of the second release film 13 can be selected from the materials exemplified in the first release film 12, provided that the relationship between F1 and F2 described above is satisfied. Specifically, the materials exemplified as heavy-release additives are preferably present in less than or not contained in the first release film 12.

[0221] The thickness of the second release film 13 is not particularly limited, but is preferably 10 μm or more and 75 μm or less. Furthermore, the thickness of the second release film is more preferably 18 μm or more, and even more preferably 24 μm or more. Furthermore, the thickness of the second release film is more preferably 60 μm or less, and even more preferably 45 μm or less. From the perspective of setting the peeling force F2 and peeling force F1 to F1 > F2 as described above, the thickness of the second release film is preferably less than or equal to the thickness of the first release film, and more preferably less than the thickness of the first release film.

[0222] Furthermore, the thickness of the second release film refers to the overall thickness of the second release film. For example, the thickness of a second release film composed of multiple layers refers to the total thickness of all the layers constituting the second release film.

[0223] The protective film forming sheet 20 is manufactured as described in the embodiment, by attaching a second release film 13 to the exposed surface of the protective film forming film 11 that is stacked with the first release film 12.

[0224] When punching the protective film forming sheet 20, the process is the same as described in the above embodiment, except that the punch enters from the side of the second release film 13 and cuts the protective film forming film 11 and the second release film 13 into a predetermined closed shape. As a result, the punched protective film forming film 11 and the second release film 13 are obtained on the first release film 12. The punched protective film forming sheet 20 can be wound into a roll for storage and transportation.

[0225] During the waste removal process, the second release film 13 and the useless portion 17 are simultaneously wound and removed. At this time, the second release film 13, which has been completely cut after being punched, is easily removed by rejoining it using a strip of adhesive tape. As a result, a protective film 16 cut into a predetermined closed shape remains on the first release film 12.

[0226] The embodiments of the present invention have been described above, but the present invention is not limited to any of the above embodiments and can be modified in various forms within the scope of the present invention.

[0227] Example

[0228] The invention will now be described in further detail with reference to the embodiments, but the invention is not limited to these embodiments.

[0229] (Manufacturing of sheets for forming protective films)

[0230] [First peeling membrane (repeated peeling membrane)]

[0231] <Coating agent containing a release agent layer>

[0232] Prepare the raw materials for the following release agent layer composition.

[0233] • Silicone release agent containing vinyl-based and hydrosilyl-based organopolysiloxanes (manufactured by Dow Corning Toray Co., Ltd., BY24-561, 30% by mass solids).

[0234] • Dimethylpolysiloxane (weight average molecular weight: 2000) (manufactured by Shin-Etsu Chemical Co., Ltd., X-62-1387, solids content 100% by mass)

[0235] • Vinyl MQ resin (manufactured by Dow Corning Toray Co., Ltd., SD-7292, 71% by mass solids) used as a heavy-duty stripping additive

[0236] • Platinum (Pt) catalyst (manufactured by Dow Corning Toray Co., Ltd., SRX-212, 100% by mass solids)

[0237] Using the mixing ratio (conversion of solid content) recorded in Table 1, the above raw materials were added to a mixed solvent of toluene and methyl ethyl ketone (toluene / methyl ethyl ketone = 1 / 1 (mass ratio)) to adjust the total solid content to 2% by mass, and a coating agent containing a release agent layer was prepared.

[0238] <Manufacturing of the First Release Film>

[0239] On a PET film (manufactured by Mitsubishi Chemical Corporation, trade name: DIAFOIL (registered trademark) T-100, thickness: 50 μm), a coating agent containing a release agent layer composition is applied to make the dried film thickness 0.15 μm, and then heated and dried to form a release agent layer on the PET film, thereby manufacturing the first release film (re-release film) A~C.

[0240] <Determination of Surface Elastic Modulus>

[0241] The surface elastic modulus of the peeling surface of the first peeling film was determined by the following method.

[0242] A cantilever (manufactured by Bruker Corporation, MultiMode8) was used on an atomic force microscope (Bruker Corporation, trade name: MLCT, tip radius: 20 nm, resonant frequency: 125 kHz, spring constant: 0.6 N / m) to hold silicon nitride material. The first release film was placed on the atomic force microscope, and the surface of the release agent layer of the first release film was pressed and pulled away using the cantilever at a pressing amount of 2 nm and a scanning speed of 10 Hz. This operation was performed at 23 °C. The force curve obtained from this operation was fitted based on the JKR theory to calculate the surface elastic modulus. For the surface elastic modulus, 4096 points were measured within a 1 μm × 1 μm area on the surface of the release agent layer of the first release film. The average value of these values ​​was taken and rounded to one decimal place as the surface elastic modulus (MPa). The results are shown in Table 1.

[0243] [Table 1]

[0244]

[0245] [Second peeling membrane (light peeling membrane)]

[0246] Using "SP-PET 381130 (thickness 38μm)" manufactured by Lintec Corporation.

[0247] [Coating agent containing a composition for forming a protective film]

[0248] The following components were mixed at the mixing ratios shown in Table 2 (conversion of solid components) and diluted with methyl ethyl ketone to a solid component concentration of 50% by mass to prepare a coating agent.

[0249] (A) Polymer composition

[0250] (A-1) A (meth)acrylate copolymer composed of 10 parts by mass of n-butyl acrylate, 70 parts by mass of methyl acrylate, 5 parts by mass of glycidyl methacrylate and 15 parts by mass of 2-hydroxyethyl acrylate (weight average molecular weight: 400,000, glass transition temperature: -1℃).

[0251] (A-2) A (meth)acrylate copolymer composed of 10 parts by mass of n-butyl acrylate, 65 parts by mass of methyl acrylate, 12 parts by mass of glycidyl methacrylate, and 13 parts by mass of 2-hydroxyethyl acrylate (weight average molecular weight: 450,000, glass transition temperature: 2°C).

[0252] (B) Curing components (thermosetting components)

[0253] (B-1) Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER828, epoxy equivalent is 184~194 g / eq)

[0254] (B-2) Acrylic rubber microparticle-dispersed bisphenol A type liquid epoxy resin (manufactured by Nippon Shokubai Co., Ltd., BPA328, epoxy equivalent of 230 g / eq, acrylic rubber content of 20 phr)

[0255] (B-3) Dicyclopentadiene type epoxy resin (manufactured by DIC CORPORATION, EPICLON HP-7200HH, softening point 88~98℃, epoxy equivalent 255~260g / eq)

[0256] (C) Curing agent: Dicyandiamine (manufactured by Mitsubishi Chemical Corporation, DICY7)

[0257] (D) Curing accelerator: 2-Phenyl-4,5-dihydroxymethylimidazol (manufactured by SHIKOKU CHEMICALS CORPORATION, CUREZOL 2PHZ)

[0258] (E) Filler material

[0259] (E-1) Epoxy-modified spherical silica filler (manufactured by Admatechs, SC2050MA, average particle size 0.5μm)

[0260] (E-2) Silica filler (Admatechs "YC100C-MLA", average particle size 0.1μm)

[0261] (F) Silane coupling agent: γ-glycidyl etheroxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM403, methoxy equivalent of 12.7 mmol / g, molecular weight of 236.3)

[0262] (G) Colorant: Carbon black (manufactured by Mitsubishi Chemical Corporation, MA600B, average particle size 28nm)

[0263] [Table 2]

[0264]

[0265] The prepared protective film forming film composition is coated onto the release surface of the first release film (any one of A to C above), and dried at 100°C for 2 minutes to form a protective film forming film with a thickness of 20 μm. Then, a second release film is attached to the protective film forming film to obtain a protective film forming sheet with a three-layer structure in which release films are formed on both sides of the protective film forming film. As attachment conditions, the temperature is 60°C, the pressure is 0.4 MPa, and the speed is 1 m / min. Then, the protective film forming sheet is cut to a width of 208 mm and wound to a length of 50 meters to form a roll.

[0266] The following measurements and evaluations were performed using the obtained protective film forming sheet.

[0267] [The protective film forms the adhesion between the films]

[0268] The protective film forming film is exposed from the protective film forming sheet by means of the following method, and the protective film forming films are attached to each other to measure the adhesion.

[0269] <Fit the protective film to the adhesive tape>

[0270] I. Peel off the second release film from the protective film forming sheet, which is a three-layer structure of the second release film / protective film forming film / first release film.

[0271] II. At 23°C, adhesive tape manufactured by Lintec Corporation (product name PET50PLシン: acrylic adhesive layer / 50μm PET substrate) is attached to the exposed protective film forming film to form a laminate sample of "PET substrate / acrylic adhesive layer / protective film forming film / first release film".

[0272] III. Cut the laminated sample into strips 25mm wide and 250mm long.

[0273] <Fixing the protective film onto the SUS plate>

[0274] I. Apply double-sided tape with PET film as the core material to the entire surface of the SUS board (0.5mm thick × 70mm × 150mm).

[0275] II. Peel off the second release film from the protective film forming sheet, which is a three-layer structure of the second release film / protective film forming film / first release film.

[0276] III. The exposed protective film is attached to the entire adhesive side of the double-sided tape to obtain a laminated sample of "SUS board / double-sided tape / protective film forming film / first release film".

[0277] IV. Peel off the first release film to expose the protective film.

[0278] <Adhesion Measurement>

[0279] Peel off the first release film from the laminate sample of "PET substrate / acrylic adhesive layer / protective film forming film / first release film" to expose the protective film forming film. Lay the laminate of "PET substrate / acrylic adhesive layer / protective film forming film" and the laminate of "SUS board / double-sided tape / protective film forming film" with the protective film forming films facing each other, using a 2kg roller at 23°C.

[0280] The adhesion was measured by the following method after the affixed material was left to stand without heating for 2 minutes (±20 seconds) after application.

[0281] Using a universal tensile testing machine (manufactured by Shimadzu Corporation, product name "AUTOGRAPH AG-IS"), the peel force was measured at a peel speed of 300 mm / min, a temperature of 23°C, and a peel angle of 180° over a test distance of 70 mm. The average of the measured values ​​between the first and last 10 mm of the test distance, averaging them over a 50 mm interval, was taken as the "adhesion between the protective film forming films".

[0282] [The peeling force F1 when the first peeling film is peeled off from the protective film forming film]

[0283] The second release film is peeled off from the obtained protective film forming sheet. A 25 μm thick layer of well-adhesive PET (manufactured by TOYOBO Co., Ltd., PET25A-4100) is then attached to the surface of the protective film forming film exposed by the peeling process using hot lamination (70°C, 1 m / min) to create a laminated sample. The laminated sample is cut into 100 mm wide pieces to create a test sample. The back side of the first release film of the test sample is fixed to a rigid support plate using double-sided tape.

[0284] Using a universal tensile testing machine (manufactured by Shimadzu Corporation, product name "AUTOGRAPH (registered trademark) AG-IS"), the protective film was peeled from the first release film at a peel angle of 180° and a peel speed of 1 m / min to form a composite (one-piece) of film / well-bonded PET, and the load at this time was measured. The total measurement distance was 100 mm, and the average of the measured values ​​between 80 mm (excluding the first 10 mm and the last 10 mm) was taken as the peel force F1. The results are shown in Table 2.

[0285] [Peeling force F2 when peeling the second peeling film off the protective film forming film]

[0286] The obtained protective film was cut into 100mm wide sheets to make samples for testing. The back side of the first release film of the test sample was fixed to a rigid support plate using double-sided tape.

[0287] Using a universal tensile testing machine (manufactured by Shimadzu Corporation, product name "AUTOGRAPH (registered trademark) AG-IS"), the second release film is peeled off from the test sample, and the load at this time is measured under the same conditions as when measuring F1 above, and is taken as the peel force F2.

[0288] The obtained peel forces F1 and F2 were compared, and for all samples, it was confirmed that F1 was greater than F2.

[0289] [Punching and waste removal of protective film forming sheets]

[0290] Using a Lintec Corporation RAD-3600F / 12 die, manufactured to 200mm wafer specifications, the die enters from the second release film side of the protective film forming sheet, punching the protective film forming film and the second release film into a circle (inner diameter 198mm). At this point, for the first release film, a notch is cut in a partially punched manner (punching process). Four dies with different cutting blade widths are used to perform half-cuts with different notch widths. Forty punching operations are performed.

[0291] After the punching process, the protective film forming sheet is moved between multiple rollers. Then, the punched circular portion remains on the first release film, and the second release film and the unused peripheral portion of the punched circular portion are removed (waste removal process). At this point, the completely cut second release film after punching is rejoined using a strip of adhesive tape, and the second release film is then removed.

[0292] <cut width>

[0293] The protective film forming sheet after the waste removal process is cut along the thickness direction without deformation of the cut portion of the first release film, keeping the protective film forming sheet flat. The cross-section is observed using a scanning electron microscope (SEM, KEYENCE CORPORATION "VE-9800"). The width of the cut remaining on the first release film at the interface between the first release film and the protective film forming film is measured.

[0294] Choose the 20th of the 40 circular segments, and measure it at 6 equally spaced points on the circumference of that circle (forming a regular hexagon if the points are connected). Take the minimum value among the 6 points as the "cut width" and round it to one decimal place.

[0295] The wider the slit, the less the protective film adheres to itself, and the more smoothly the waste can be removed.

[0296] <Evaluation of Waste Removability>

[0297] During the waste removal process, the number of protective film flakes that float up along with the useless parts in each of the 40 circular sections is counted. The fewer the number of floating flakes, the less the protective film flakes adhere to each other, and the smoother the waste removal process will be.

[0298] The results are summarized in Table 3.

[0299] [Table 3]

[0300]

[0301] As can be confirmed from Table 3, if the adhesion between the protective film forming films is less than 19N, the protective film forming films will not adhere to each other after the punching process, and waste removal can be carried out smoothly. Furthermore, as shown in Example 7, if the cut width becomes narrower, there is a tendency for the protective film forming films to adhere to each other after the punching process, making waste removal difficult.

[0302] Industrial applicability

[0303] As described above, according to the present invention, a protective film forming sheet and a method thereof can be provided that can sufficiently suppress the poor removal of waste material even when the kerf width is narrow during punching.

Claims

1. A protective film forming sheet, which is a strip and has a single-layer protective film forming film and a first release film disposed on one side of the protective film forming film, wherein, The protective film forming film is laminated on the first release film in a peelable manner. The adhesion of the two protective films formed by attaching them to each other at 23°C with a load of 2 kgf for 2 minutes is less than 19 N / 25 mm.

2. A protective film forming sheet, which is an elongated sheet and has a first release film, a second release film, and a protective film forming film sandwiched between the first release film and the second release film, wherein, The adhesion of the two protective films formed by attaching them to each other at 23°C with a load of 2 kgf for 2 minutes is less than 19 N / 25 mm.

3. A protective film forming sheet, which is an elongated sheet and has a protective film forming film containing a filler material and a first release film disposed on one side of the protective film forming film, wherein, The adhesion of the two protective films formed by attaching them to each other at 23°C with a load of 2 kgf for 2 minutes is less than 19 N / 25 mm.

4. A method for processing a workpiece, comprising processing a workpiece using a protective film forming sheet, wherein the protective film forming sheet is a strip and has a protective film forming film and a first release film disposed on one side of the protective film forming film, and the adhesion force after two protective film forming films are bonded together at 23°C with a load of 2 kgf for 2 minutes is less than 19 N / 25 mm, wherein the protective film forming film is laminated on the first release film in a peelable manner, wherein... The processing methods for this workpiece include: The process of attaching the protective film forming film of the protective film forming sheet to the back of the workpiece while the first release film has a protective film forming film on it; The process of forming a protective film from an applied film; and The process of peeling the first release film off the protective film or protective film forming film.

5. The sheet for forming a protective film according to any one of claims 1 to 3, wherein, The surface elastic modulus of the surface of the first release film that is in contact with the protective film is less than 17 MPa.

6. The sheet for forming a protective film according to any one of claims 1 to 3, wherein, On the protective film forming sheet, a cut is formed in such a way that a portion of the protective film forming sheet has a predetermined closed shape when viewed from above. The cut extends through the protective film forming film in the thickness direction of the protective film forming sheet and reaches a portion of the first release film.

7. The protective film forming sheet according to claim 6, wherein the width of the cut at the interface between the protective film forming film and the first release film is 8 μm or more.

8. A method for manufacturing a protective film forming sheet by punching, comprising a step of forming a cut in such a way that a portion of the protective film forming sheet according to any one of claims 1 to 3 has a predetermined closed shape. The cut extends through the protective film forming film in the thickness direction of the protective film forming sheet and reaches a portion of the first release film.

9. The method for manufacturing a protective film forming sheet after punching according to claim 8, wherein, The width of the cut at the interface between the protective film forming film and the first peeling film is 8 μm or more.

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