Protective film forming sheet and method for producing the same

Abstract

The present invention provides a protective film-forming sheet capable of sufficiently suppressing the cessation of waste material removal, and a method for manufacturing the protective film-forming sheet. The protective film-forming sheet of the present invention is a long sheet comprising: a protective film-forming film for forming a protective film; a first release film provided on one surface of the protective film-forming film; and a second release film provided on the other surface of the protective film-forming film. The protective film-forming sheet is characterized in that, when the peeling force when peeling the first release film from the protective film-forming film is defined as F1 and the peeling force when peeling the second release film from the protective film-forming film is defined as F2, the relationship F1>F2 is satisfied; when the adhesive force of the protective film-forming film to a stainless steel plate is defined as F3, the relationship F2 / F3≥0.10 is satisfied, and F2 is 30 mN / 100 mm or greater.

Description

Technical Field

[0001] The present invention relates to a protective film-forming sheet and a method for producing the same. In particular, the present invention relates to a protective film-forming sheet having a protective film suitable for protecting a workpiece such as a semiconductor wafer or a processed product such as a semiconductor chip obtained by processing the workpiece, and a method for producing the protective film-forming sheet. Background Art

[0002] 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 a circuit surface formed with protruding electrodes such as bumps, the circuit surface of the semiconductor chip is flipped over (face down) and bonded to a chip mounting portion. As a result, the semiconductor device has a structure where the back side of the semiconductor chip, where no circuitry is formed, is exposed.

[0003] Therefore, in order to protect the semiconductor chip from impacts such as during transportation, a hard protective film formed of an organic material is often formed on the back side of the semiconductor chip. In order to form this protective film, an uncured resin film (hereinafter referred to as a "protective film forming film") is used as its precursor. The protective film forming film is attached to the back of the semiconductor wafer and is cut together with the wafer to form a chip. By curing the protective film forming film, a chip with a protective film on the back can be obtained.

[0004] Patent Document 1 discloses a three-layer protective film forming sheet 10, such as Figure 1 As shown, a protective film forming film 11 is sandwiched between a first peeling film 12 and a second peeling film 13. The protective film forming film 11 is laminated in such a manner that it can be peeled off from the first peeling film 12 and the second peeling film 13. When the peeling force when peeling the first peeling film 12 from the protective film forming film 11 is set to F1, and the peeling force when peeling the second peeling film 13 from the protective film forming film 11 is set to F2, the protective film forming sheet of patent document 1 satisfies F1>F2. The above-mentioned protective film forming sheet 10 is a long strip and is stored and transported in a roll-like manner. In addition, the protective film forming sheet 10 is sometimes used to attach to a workpiece after pre-punching the protective film forming film into a shape roughly the same as that of a workpiece (a general term for adherends such as semiconductor wafers). As Figure 2 As shown in FIG. 1 , in the punched protective film forming sheet, the protective film forming film 16 punched into a predetermined closed shape is sandwiched between two release films (12, 13). Figure 2 , the state before the useless portion 17 is removed is shown.

[0005] The punched protective film forming sheet is produced by punching the protective film forming film into a predetermined closed shape using a die, and is used by removing the second release film 13 and the unnecessary portion 17 around the punched protective film forming film 16. Specifically, the cutout 14 is made so that the protective film forming film 11 and the second release film 13 are completely punched into the predetermined closed shape and the first release film 12 is not completely punched, thereby obtaining a punched protective film forming sheet ( Figure 3 This process is called a "punching process". Then, a protective film forming film 16 of a predetermined closed shape is left on the first peeling film 12 and the second peeling film 13 and the surrounding useless portion 17 are removed ( Figure 4 ), and then a protective film is attached to the workpiece to form a film 16. The process of removing the useless part 17 is called a "waste removal process".

[0006] Before the above-mentioned waste removal process, a long strip of adhesive tape 18 is adhered to the second peeling film connected to the useless portion 17 and the second peeling film connected to the punched protective film forming film 16. When the waste removal process is performed, the useless portion 17 can be removed and the long strip of adhesive tape 18 and the second peeling film 13 (that is, the second peeling film connected to the useless portion 17 and the second peeling film connected to the punched protective film forming film 16) can be removed at the same time.

[0007] When removing the second release film 13 from the punched protective film forming film 16 , the relationship F1 > F2 is satisfied, so the second release film 13 is easily removed and the punched protective film forming film 16 can be reliably left on the first release film 12 .

[0008] Protective film-forming sheets require stable punching (operational stability). In particular, stable operation is required during the waste removal process, which removes unnecessary portions after punching the protective film-forming sheet. More specifically, the waste removal process must be performed without the problem of being unable to continuously remove the unnecessary portions 17 and requiring the operation to be stopped (hereinafter also referred to as "waste removal stop").

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: International Publication No. WO2017 / 145735 Summary of the Invention

[0012] Technical Problems to be Solved by the Invention

[0013] The inventors of the present invention diligently studied the cause of the stoppage of waste material removal, and as a result, obtained the following findings.

[0014] like Figure 5 As shown, after the punching process, the second release film 13 and the unnecessary portion 17 of the protective film-forming film are removed in a waste removal process and finally wound onto a waste roller 20 for disposal. The unnecessary portion 17 peeled from the first release film is long and continuous. Before reaching the waste roller 20, a tension roller 19 is positioned to control the tension of the unnecessary portion 17. These rollers 19 and 20 are typically made of stainless steel.

[0015] When passing through the tension roller 19, the useless portion 17 (i.e., the unnecessary protective film-forming film) may come into contact with the tension roller 19. Since the peeling force F2 between the protective film-forming film 11 and the second release film 13 is set relatively weak, some or all of the protective film-forming film may peel off from the second release film 13 and be transferred to the tension roller 19, contaminating the tension roller 19. In such cases, the apparatus needs to be stopped and the tension roller 19 cleaned.

[0016] Furthermore, since the useless portion 17 is in continuous contact with the tension roller 19, if a large amount of residue of the protective film forming film remains on the tension roller 19, it may cause a malfunction in the operation of the tension roller 19. Furthermore, the residue adhering to the tension roller 19 may flake off into the apparatus and contaminate the protective film forming sheet as a product.

[0017] The present invention has been made in view of the above-mentioned actual situation, and an object of the present invention is to provide a protective film forming sheet capable of sufficiently suppressing the suspension of waste material removal, and a method for producing the protective film forming sheet.

[0018] Technical means to solve technical problems

[0019] The solutions of the present invention are as follows.

[0020] (1) A sheet for forming a protective film, which is a long sheet and comprises: a protective film-forming film for forming a protective film, a first release film provided on one surface of the protective film-forming film, and a second release film provided on the other surface of the protective film-forming film, wherein:

[0021] When the peeling force when peeling the first peeling film from the protective film-forming film is F1 and the peeling force when peeling the second peeling film from the protective film-forming film is F2, the relationship F1>F2 is satisfied.

[0022] When the adhesion of the protective film-forming film to the stainless steel plate is defined as F3, the relationship F2 / F3≥0.10 is satisfied.

[0023] F2 is 30mN / 100mm or more.

[0024] (2) The protective film-forming sheet according to (1), wherein the weight of the epoxy resin that is liquid at room temperature contained in the protective film-forming composition is 12 parts by mass or less, based on 100 parts by mass of the total weight of the protective film-forming composition constituting the protective film-forming film.

[0025] (3) The protective film-forming sheet according to (1) or (2), wherein the weight of the filler contained in the protective film-forming composition is less than 55 parts by mass when the total weight of the protective film-forming composition constituting the protective film-forming film is 100 parts by mass.

[0026] (4) The protective film-forming sheet according to any one of (1) to (3), wherein

[0027] The protective film forming sheet has a cutout formed therein so that a portion of the protective film forming sheet has a predetermined closed shape when the protective film forming sheet is viewed from above.

[0028] The incision penetrates the protective-film-forming film in the thickness direction of the protective-film-forming sheet and reaches a portion of the first release film.

[0029] (5) A method for producing a punched protective film-forming sheet, comprising the step of forming a notch so that a portion of the protective film-forming sheet according to any one of (1) to (3) above has a predetermined closed shape.

[0030] The incision penetrates 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] Effects of the Invention

[0032] According to the present invention, a protective film-forming sheet capable of sufficiently suppressing stoppage of waste material removal and a method for producing the same can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic cross-sectional view of a protective film forming sheet according to an embodiment

[0034] Figure 2 It is a schematic cross-sectional view showing a state in which the protective film forming sheet according to the embodiment is punched.

[0035] Figure 3 This is a schematic perspective view of the protective film forming sheet after the punching process.

[0036] Figure 4 A schematic perspective view showing the waste removal process.

[0037] Figure 5This is a cross-sectional view showing a state where the second release film and the unnecessary portion pass through the tension roller.

[0038] Figure 6 This is a schematic cross-sectional view of an example of a chip having a protective film obtained by converting the protective film-forming film of this embodiment into a protective film.

[0039] Figure 7 It is a schematic cross-sectional view for explaining the step of attaching the protective film forming sheet of this embodiment to a wafer.

[0040] Figure 8 A schematic cross-sectional view illustrating a singulation process of a wafer with a protective film.

[0041] Figure 9 A schematic cross-sectional view illustrating the process of placing a chip with a protective film on a substrate.

[0042] Description of Reference Numerals

[0043] 10: Sheet for forming a protective film (this embodiment); 11: Protective film forming film; 12: First peeling film; 13: Second peeling film; 14: Incision; 16: Protective film forming film after punching; 17: Useless part; 18: Long adhesive tape; 19: Tension roller; 20: Waste roller; 21: Wafer; 22: Cutting sheet; 30: Chip with protective film; 31: Chip; 32: Protective film; 33: Protruding electrode; 50: Substrate. DETAILED DESCRIPTION

[0044] First, main terms used in this specification are explained.

[0045] The workpiece is a plate-like object to be processed and attached to the protective film-forming film of this embodiment. Examples of the workpiece include wafers and panels. Specifically, semiconductor wafers and semiconductor panels can be used. Examples of processed products of the workpiece include chips obtained by singulating a wafer. Specifically, semiconductor chips obtained by singulating a semiconductor wafer can be used. In this case, the protective film is formed on the back side of the wafer and chip.

[0046] The “front surface” of a workpiece such as a wafer refers to the surface on which circuits and protruding electrodes such as bumps are formed, while the “back surface” refers to the surface on which no circuits or electrodes (such as protruding electrodes such as bumps) are formed.

[0047] In this specification, for example, “(meth)acrylate” is used as a term representing both “acrylate” and “methacrylate”, and the same applies to other similar terms.

[0048] The release film is a film that supports the protective film forming film in a releasable manner. The film is not limited in thickness and is used as a concept including a sheet.

[0049] The mass ratios in the descriptions of the protective film-forming film composition and the release agent layer composition are based on the active ingredients (solid content), and the solvent is not included unless otherwise specified.

[0050] Hereinafter, the present invention will be described based on specific embodiments.

[0051] (1. Protective film forming film)

[0052] like Figure 1 、 Figure 3 As shown, the protective film forming sheet 10 of this embodiment is a long strip sheet and has: a protective film forming film 11, a first peeling film 12 arranged on one surface of the protective film forming film 11, and a second peeling film 13 arranged on the other surface. The protective film forming sheet 10 is usually wound into a roll.

[0053] The protective film-forming film 11 is attached to a workpiece and formed into a protective film, thereby forming a protective film for protecting the workpiece or a product processed from the workpiece.

[0054] "Protecting" means bringing the protective film-forming film 11 into a state having sufficient properties to protect a workpiece or a workpiece-processed product. Specifically, when the protective film-forming film of this embodiment is curable, "protecting" means converting an uncured protective film-forming film into a cured product. In other words, the protective film-forming film that has undergone the protective film-forming process is a cured product of the protective film-forming film and is different from the protective film-forming film.

[0055] After a workpiece is superimposed on the curable protective film-forming film, the protective film-forming film is cured, whereby the protective film can be firmly bonded to the workpiece, and a durable protective film can be formed.

[0056] When the protective film forming film 11 does not contain a curable component and is used in an uncured state, the protective film forming film of this embodiment is converted into a protective film when it is attached to a workpiece.

[0057] When high protection performance is not required, the protective film-forming film does not need to be cured, and thus the protective film-forming film may be non-curable.

[0058] In this embodiment, the protective film-forming film is preferably curable. Therefore, the protective film is preferably a cured product. Examples of cured products include heat-cured products and energy-ray cured products. In this embodiment, the protective film is more preferably a heat-cured product.

[0059] The protective film-forming film preferably has adhesiveness at room temperature (23°C) or preferably develops adhesiveness by heating. This allows the workpiece and the protective film-forming film to be adhered to each other when they are superimposed. This allows for reliable positioning before curing the protective film-forming film.

[0060] The protective film-forming film may be composed of a single layer (single layer) or a plurality of layers. When the protective film-forming film has multiple layers, these multiple layers may be the same as or different from each other, and the combination of layers constituting these multiple layers is not particularly limited.

[0061] In this embodiment, the protective film-forming film is preferably a single layer (monolayer). If the protective film-forming film is composed of multiple layers, there is a risk of delamination due to differences in thermal expansion and contraction between the layers during processes where temperature changes occur (during reflow processing or when using the device). If the protective film-forming film is a single layer, this risk can be reduced.

[0062] The thickness of the protective film-forming film is not particularly limited, but is preferably 100 μm or less, more preferably 70 μm or less, more preferably 45 μm or less, and particularly preferably 30 μm or less. If the thickness of the protective film-forming film is within this range, the adhesive force F3 (described later) tends to be reduced. Furthermore, the thickness of the protective film-forming 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-forming film is within this range, the protective performance of the resulting protective film is improved.

[0063] The thickness of the protective film-forming film refers to the thickness of the entire protective film-forming film. For example, the thickness of a protective film-forming film composed of multiple layers refers to the total thickness of all layers constituting the protective film-forming film.

[0064] The following describes a protective film formed on a chip as a workpiece. Figure 6 The chip 30 with a protective film shown will be described as a protective film formed by converting the protective film forming film of this embodiment into a protective film.

[0065] like Figure 6 As shown, the chip 30 with the protective film is on the back side of the chip 31 (on the Figure 6 A protective film 32 is formed on the surface side of the chip 31 (in the Figure 6 A convex electrode 33 is formed on the lower side (in the middle).

[0066] Chip 31 has a circuit formed on its surface, and protruding electrodes 33 are formed on this surface to electrically connect to the circuit. Chip 30 with a protective film is positioned so that the surface with protruding electrodes 33 faces the chip mounting substrate. Then, through a predetermined heat treatment (reflow soldering), the protruding electrodes 33 are electrically and mechanically connected to the substrate, allowing for mounting. Examples of protruding electrodes 33 include bumps and pillar electrodes.

[0067] (1.1 Peeling properties of protective film forming film)

[0068] In this embodiment, the peel force F1 when peeling the first release film 12 from the protective film-forming film 11 and the peel force F2 when peeling the second release film from the protective film-forming film satisfy the relationship F1>F2, preferably F1>1.2×F2, more preferably F1>1.5×F2, and even more preferably F1>2×F2. If the peel force F1 and the peel force F2 satisfy this relationship, the second release film can be easily removed from the punched protective film-forming film 16, ensuring that the punched protective film-forming film 16 remains on the first release film 12. Therefore, the first release film 12 is a heavy release film with a strong peel force, while the second release film 13 is a light release film with a weak peel force. While the upper limit of the peel force F1 is not particularly limited, the relationship between the peel force F1 and the peel force F2 preferably satisfies the relationship F1<10×F2, more preferably F1<7×F2, more preferably F1<5×F2, and particularly preferably F1<3.5×F2. If the peel force F1 and the peel force F2 satisfy the above relationship, the unnecessary portion 17 can be easily removed from the first release film. Furthermore, F2 is 30 mN / 100 mm or greater, preferably 36 mN / 100 mm or greater, more preferably 42 mN / 100 mm or greater, further preferably 50 mN / 100 mm or greater, and particularly preferably 60 mN / 100 mm or greater.

[0069] In this embodiment, when the adhesion of the protective film-forming film to the stainless steel plate is defined as F3, F2 / F3 ≥ 0.10 is satisfied, preferably F2 / F3 ≥ 0.15, more preferably F2 / F3 ≥ 0.20, and even more preferably F2 / F3 ≥ 0.30 is satisfied. By ensuring that F2 and F3 satisfy this relationship, when the second release film 13 and the unnecessary portion 17 are wound, even if the unnecessary portion 17 (i.e., the unnecessary protective film-forming film) contacts the stainless steel tension roller, the protective film-forming film will not remain attached to the tension roller, and the second release film 13 and the unnecessary portion 17 can be wound. The upper limit of F2 / F3 is not particularly limited, but if F2 is too large, the second release film may not be smoothly peeled off when using the protective film-forming film. Therefore, F2 / F3 ≤ 1.2 is preferred, F2 / F3 ≤ 0.8 is more preferred, F2 / F3 ≤ 0.6 is more preferred, and F2 / F3 ≤ 0.5 is particularly preferred.

[0070] The peel force F1 is preferably 50 mN / 100 mm or greater, more preferably 70 mN / 100 mm or greater, even more preferably 90 mN / 100 mm or greater, even more preferably 110 mN / 100 mm or greater, and particularly preferably 130 mN / 100 mm or greater. By setting F1 within the above range, unintended peeling of the protective film-forming film 11 and the first release film 12 can be suppressed.

[0071] In addition, the adhesion force F3 is preferably 500mN / 100mm or less, more preferably 400mN / 100mm or less, more preferably 350mN / 100mm or less, and particularly preferably 300mN / 100mm or less. By making F3 within the above range, it is possible to prevent the useless portion 17 (i.e., the unnecessary protective film forming film) from remaining attached to the tension roller. The adhesion force F3 is preferably 40mN / 100mm or more, more preferably 80mN / 100mm or more, and more preferably 120mN / 100mm or more. If F3 is too low, the adhesion to the workpiece may sometimes decrease excessively. When measuring the adhesion force F3 of the protective film forming film to the stainless steel plate, the adhesion force after about 2 minutes after the protective film forming film is attached to the stainless steel plate is measured. This is because the protective film forming sheet is suspended from the time the second release film 13 and the unnecessary portion 17 of the protective film forming film are pulled up in the waste removal step to the time they are finally wound up on the waste removal roller, and the unnecessary portion is in contact with the tension roller for about 2 minutes.

[0072] (1.2 Protective Film-Forming Composition)

[0073] As long as the protective film forming film has the above-mentioned physical properties, the composition of the protective film forming film is not particularly limited. In the present embodiment, the composition constituting the protective film forming film (protective film forming film composition) is preferably a resin composition containing at least a polymer component (A), a curable component (B), and a filler (E). The polymer component is regarded as a component formed by a polymerization reaction of a polymerizable compound. In addition, the curable component is a component that can undergo a curing (polymerization) reaction. In addition, the polymerization reaction in the present invention also includes a polycondensation reaction.

[0074] In addition, components contained in the polymer component may also be curable components. In this embodiment, when the protective film-forming film composition contains such components that are both polymer components and curable components, it is considered that the protective film-forming film composition contains the polymer component and the curable component.

[0075] (1.2.1 Polymer composition)

[0076] The polymer component (A) makes the protective film-forming film have film-forming properties and gives it appropriate viscosity so that the protective film-forming film is surely and evenly attached to the workpiece. The weight average molecular weight of the polymer component is usually in the range of 50,000 to 2 million, preferably in the range of 100,000 to 1.5 million, and particularly preferably in the range of 200,000 to 1 million. If the weight average molecular weight is too low, there is a tendency for the peeling force of the peeling film and the adhesion to the stainless steel plate to increase. On the other hand, if the weight average molecular weight is too high, the compatibility with other components deteriorates, which results in the formation of a uniform film. As such a polymer component, for example, acrylic resins, urethane resins, phenoxy resins, silicone resins, saturated polyester resins, etc. can be used, and acrylic resins are particularly preferably used.

[0077] In addition, in this specification, unless otherwise specified, the "weight average molecular weight" is a polystyrene conversion value measured by gel permeation chromatography (GPC). As a measurement by this method, for example, a high-efficiency GPC device "HLC-8120GPC" manufactured by TOSOH CORPORATION, in which a high-efficiency chromatography column "TSK gurdcolumn H XL -H","TSK Gel GMH XL ”,TSK Gel G2000 H XL The measurement was performed using a differential refractometer as a detector at a column temperature of 40°C and a liquid feed rate of 1.0 mL / min using a TOSOH CORPORATION device.

[0078] Examples of acrylic resins include (meth)acrylate copolymers composed of a (meth)acrylate monomer and a structural unit derived from a (meth)acrylic acid derivative. Preferred (meth)acrylate monomers include alkyl (meth)acrylates having an alkyl group with 1 to 18 carbon atoms, specifically methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and butyl (meth)acrylate. Examples of (meth)acrylic acid derivatives include (meth)acrylic acid, glycidyl (meth)acrylate, and hydroxyethyl (meth)acrylate.

[0079] In this embodiment, glycidyl methacrylate or the like is preferably used to introduce glycidyl groups into the acrylic resin. Acrylic resins with glycidyl groups introduced improve compatibility with the epoxy resin (described later as a thermosetting component), resulting in a higher glass transition temperature (Tg) of the protective film-forming film after curing, thereby enhancing heat resistance. Furthermore, in this embodiment, hydroxyethyl acrylate or the like is preferably used to introduce hydroxyl groups into the acrylic resin in order to control adhesion or tackiness to workpieces.

[0080] 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 this range, the fluidity of the protective film-forming film and the protective film during heating can be suppressed, thereby facilitating the formation of a smooth protective film. If the glass transition temperature is too low, the peeling force of the release film and the adhesion to the stainless steel plate tend to increase. If the glass transition temperature is too high, compatibility with other components deteriorates, resulting in impaired uniform film formation and a tendency for the peeling force F2 of the second release film to be excessively reduced.

[0081] When an acrylic resin has m types of structural units (m is an integer greater than or equal to 2), the glass transition temperature of the acrylic resin can be calculated as follows. Specifically, the m types of monomers from which the structural units in the acrylic resin are derived are sequentially assigned non-repeating numbers from 1 to m and designated "monomer m." The glass transition temperature (Tg) of the acrylic resin can be calculated using the Fox equation shown below.

[0082] [Mathematical formula 1]

[0083]

[0084] Wherein, Tg is the glass transition temperature of the 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 the structural unit m derived from monomer m in the acrylic resin, and Wk satisfies the following formula.

[0085] [Mathematical formula 2]

[0086]

[0087] Wherein, m and Wk are the same as those described above.

[0088] As Tgk, the values described in the Polymer Data Handbook, the Adhesion Handbook, or the Polymer Handbook can be used. For example, the Tgk of a homopolymer of methyl acrylate is 10°C, the Tgk of a homopolymer of n-butyl acrylate is -54°C, the Tgk of a homopolymer of methyl methacrylate is 105°C, the Tgk of a homopolymer of 2-hydroxyethyl acrylate is -15°C, the Tgk of a homopolymer of glycidyl methacrylate is 41°C, and the Tgk of 2-ethylhexyl acrylate is -70°C.

[0089] 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, even more preferably 14 to 50 parts by mass, and particularly preferably 15 to 45 parts by mass, based on the total weight of the protective film-forming film composition of 100 parts by mass. By keeping the content of the polymer component within the above range, the amount of low-molecular-weight components that increase the release strength of the release film and the adhesion to the stainless steel plate can be limited to an appropriate range, thereby facilitating the material design of the protective film-forming film composition.

[0090] (1.2.2 Thermosetting components)

[0091] The curable component (B) cures the protective film-forming film to form a hard protective film. A thermosetting component, an energy-ray curable component, or a mixture thereof can be used as the curable component. When cured by energy ray irradiation, the protective film-forming film of this embodiment contains fillers and colorants, etc., which will be described later, and thus has a reduced light transmittance. Therefore, for example, when the protective film-forming film becomes thicker, energy-ray curing tends to be insufficient.

[0092] On the other hand, even when the thickness of the thermosetting protective film forming film increases, it can be fully cured by heating, thereby forming a protective film with high protective performance. In addition, by using conventional heating equipment such as a heating oven, multiple protective film forming films can be heated and thermally cured at once.

[0093] Therefore, in this embodiment, the curable component is preferably thermosetting. In other words, the protective film-forming film of this embodiment is preferably thermosetting.

[0094] Whether a protective film-forming film is thermosetting can be determined as follows. First, a protective film-forming film at room temperature (23°C) is heated to a temperature higher than room temperature and then cooled to room temperature to form a heated and cooled protective film-forming film. Next, at the same temperature, the hardness of the heated and cooled protective film-forming film is compared with the hardness of the protective film-forming film before heating. If the heated and cooled protective film-forming film is harder, the protective film-forming film is determined to be thermosetting.

[0095] Preferred thermosetting components include, for example, epoxy resins, thermosetting polyimide resins, unsaturated polyester resins, and mixtures thereof. Furthermore, thermosetting polyimide resins are a general term for low-molecular-weight, low-viscosity monomers or precursor polymers that are thermally cured to form polyimide resins. Non-limiting examples of thermosetting polyimide resins are described in, for example, the Journal of the Japanese Society of Fiber Research, "Fibers and Industry," Vol. 50, No. 3 (1994), pp. 106-118.

[0096] The epoxy resin, which is a thermosetting component, has the property of forming a three-dimensional network when heated, forming a strong coating. As such epoxy resin, various known epoxy resins can be used. 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. In addition, 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.

[0097] Specific examples of such epoxy resins include glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenol novolac, and cresol novolac; 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 alkylglycidyl epoxy resins in which the active hydrogen bonded to the nitrogen atom of aniline isocyanurate, etc., is substituted with a glycidyl group; and so-called alicyclic epoxides in which epoxy groups are introduced by, for example, oxidizing the carbon-carbon double bond in the molecule, such as vinylcyclohexane diepoxide, 3,4-epoxycyclohexylmethyl-3,4-dicyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane. In addition, epoxy resins having a biphenyl skeleton, a dicyclohexadiene skeleton, a naphthalene skeleton, or the like can also be used.

[0098] Among these epoxy resins, when using an epoxy resin that is liquid at room temperature (23°C), the weight of the epoxy resin that is liquid at room temperature is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, and even more preferably 1 to 11 parts by mass, based on the total weight of the protective film-forming film composition being 100 parts by mass. If a large amount of such a liquid epoxy resin is included, the peeling force when peeling the release film from the protective film-forming film and the adhesive strength to the stainless steel plate tend to increase.

[0099] Examples of epoxy resins that are liquid at room temperature (23°C) (liquid epoxy resins) include resins with smaller molecular weights such as glycidyl ether of bisphenol A (bisphenol A-type epoxy resin), glycidyl ether of bisphenol F (bisphenol F-type epoxy resin), phenol novolac-type epoxy resins, naphthalene-type epoxy resins, cyclohexanedimethanol-type epoxy resins, and glycidylamine-type epoxy resins.

[0100] When a thermosetting component is used as the curing component (B), it is preferred to use a curing agent (C) as an auxiliary agent. As a curing agent for epoxy resin, a heat-activated latent epoxy resin curing agent is preferred. "Heat-activated 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 or above, thereby reacting with epoxy resin. Methods for activating heat-activated latent epoxy resin curing agents include a method of generating active species (anions, cations) in a chemical reaction based on heating; a method of stably dispersing in epoxy resin at around room temperature, but being compatible with epoxy resin, dissolving and initiating a curing reaction at high temperature; a method of dissolving a molecular sieve-encapsulated curing agent at high temperature and initiating a curing reaction; a method based on microcapsules, etc.

[0101] Among the methods exemplified above, a method in which the precipitant is stably dispersed in the epoxy resin at around room temperature but is compatible with and dissolved in the epoxy resin at high temperature to initiate a curing reaction is preferred.

[0102] Specific examples of heat-activated latent epoxy resin curing agents include various onium salts, dibasic acid dihydrazide compounds, dicyandiamide, amine adduct curing agents, imidazole compounds, and other high-melting-point active hydrogen compounds. These heat-activated latent epoxy resin curing agents can be used alone or in combination of two or more. In this embodiment, dicyandiamide is particularly preferred.

[0103] In addition, as a curing agent for epoxy resin, phenolic resin is also preferred. As the phenolic resin, condensates of phenols such as alkylphenols, polyphenols, naphthols and aldehydes can be used without particular limitation. Specifically, phenol novolac resin, o-cresol novolac resin, p-cresol novolac resin, tert-butylphenol novolac resin, dicyclopentadiene cresol resin, poly-p-vinyl phenolic resin, bisphenol A novolac resin or modified products thereof can be used.

[0104] The phenolic hydroxyl groups contained in these phenol resins can easily undergo an addition reaction with the epoxy groups of the above-mentioned epoxy resins by heating, thereby forming a cured product having high impact resistance.

[0105] The content of the curing agent (C) is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, even more preferably 0.2 to 15 parts by mass, and particularly preferably 0.3 to 10 parts by mass, relative to 100 parts by mass of the epoxy resin. By setting the content of the curing agent (C) within the above range, the network structure of the protective film becomes dense, and the performance of the protective film in protecting the workpiece is easily achieved.

[0106] When dicyandiamide is used as the curing agent (C), it is preferred to use a curing accelerator (D) simultaneously. Preferred curing accelerators include imidazoles (imidazoles in which one or more hydrogen atoms are replaced by groups other than hydrogen atoms), such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Among these, 2-phenyl-4-methyl-5-hydroxymethylimidazole is particularly preferred.

[0107] The content of the curing accelerator is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, even more preferably 0.2 to 15 parts by mass, and particularly preferably 0.3 to 10 parts by mass, relative to 100 parts by mass of the epoxy resin. By setting the content of the curing accelerator (D) within the above range, the network structure of the protective film becomes dense, thereby easily achieving the performance of the protective film in protecting the workpiece.

[0108] The combined content of the thermosetting component and 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, based on 100 parts by mass of the total weight of the protective film-forming composition. When the thermosetting component and curing agent are blended in this ratio, moderate adhesion is achieved before curing, allowing for stable application. Furthermore, after curing, the protective film is more likely to provide the desired performance, protecting the workpiece.

[0109] If low molecular weight compounds are used as thermosetting components and curing agents, the viscosity of the protective film-forming film may increase, and the peeling force of the release film and the adhesion to the stainless steel plate may increase. Therefore, it is preferable to select the type and amount of thermosetting components and curing agents within the above range so as to control the viscosity to an appropriate value.

[0110] (1.2.3 Energy ray curable component)

[0111] When the curable component (B) is an energy ray-curable component, the energy ray-curable component is preferably uncured, preferably has adhesiveness, and more preferably is uncured and has adhesiveness.

[0112] The energy ray-curable component is a component that is cured by irradiation with energy rays and is a component for imparting film-forming properties, flexibility, and the like to the protective film-forming film.

[0113] As the energy-ray curable component, for example, a compound having an energy-ray curable group is preferable. Examples of such a compound include known energy-ray curable components.

[0114] If a low molecular weight compound is used as an energy-ray curable component, the viscosity of the protective film forming film may increase, and the peeling force of the release film and the adhesion to the stainless steel plate may increase. Therefore, it is preferable to select the type and amount of the energy-ray curable component so as to control the viscosity to an appropriate value.

[0115] (1.2.4 Filling materials)

[0116] By incorporating a filler (E) into the protective film-forming film, the thermal expansion coefficient of the protective film formed by converting the protective film into a protective film can be easily adjusted. By adjusting the thermal expansion coefficient to be close to that of the workpiece, the bonding reliability of the package formed using the protective film-forming film is further improved. Furthermore, by incorporating a filler (E) into the protective film-forming film, a hard protective film can be obtained, further reducing the moisture absorption rate of the protective film, and further improving the bonding reliability of the package.

[0117] The filler (E) may be either an organic filler or an inorganic filler, but is preferably an inorganic filler from the viewpoint of shape stability at high temperatures.

[0118] Preferred inorganic fillers include powders such as silica, alumina, talc, calcium carbonate, red iron oxide, silicon carbide, and boron nitride; beads obtained by sphericalizing these inorganic fillers; surface-modified products of these inorganic fillers; single-crystal fibers of these inorganic fillers; and glass fibers. Among these, silica and surface-modified silica are preferred. Surface-modified silica is preferably surface-modified using a coupling agent, more preferably using a silane coupling agent.

[0119] The average particle size of the filler is preferably 0.02 to 10 μm, more preferably 0.05 to 5 μm, and particularly preferably 0.10 to 3 μm.

[0120] By setting the average particle size of the filler to the above value, the workability of the protective film-forming composition becomes good, and thus the quality of the protective film-forming composition and the protective film-forming film tends to be stabilized.

[0121] In addition, unless otherwise specified, the "average particle size" in this specification refers to the particle size (D50) at 50% of the cumulative value in the particle size distribution curve determined by a laser diffraction scattering method.

[0122] When the total weight of the protective film-forming film composition is set to 100 parts by mass, the upper limit of the filler content is preferably less than 80 parts by mass, more preferably less than 70 parts by mass, more preferably less than 60 parts by mass, and particularly preferably less than 55 parts by mass, and the lower limit is preferably 15 parts by mass or more, more preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and particularly preferably 45 parts by mass or more.

[0123] By setting the filler content to the above values, it is easier to control the peeling force of the release film and the adhesion to the stainless steel plate within an appropriate range. If the filler content is too low, the viscosity of the protective film-forming film increases, and the peeling force of the release film and the adhesion to the stainless steel plate are excessively increased. On the other hand, if the filler content is too high, the conformability of the protective film-forming film may be reduced, and the film may lose its shape due to bending on rollers such as tension rollers, and the protective film-forming film may easily peel off or remain attached to the roller.

[0124] Furthermore, the protective film-forming film preferably contains two or more fillers. That is, the filler (E) is preferably a mixture of two or more fillers. “Containing two or more fillers” may include two or more fillers of different materials or two or more fillers of different average particle sizes.

[0125] In this embodiment, it is preferred to include two or more fillers having different average particle sizes. By including fillers having different average particle sizes in the protective film-forming film, it is easier to place a filler having a smaller average particle size in the gaps between fillers having a larger average particle size. As a result, the aforementioned effects can be achieved, and the adhesion between the protective film-forming films can be easily adjusted to within the aforementioned range.

[0126] When two or more fillers having different average particle sizes are contained, the average particle size of the filler with the largest average particle size is preferably 1.5 to 100 times, more preferably 2 to 20 times, and even more preferably 3 to 18 times the average particle size of the filler with the smallest average particle size.

[0127] Furthermore, whether or not the protective film or protective film-forming film contains two or more fillers having different average particle sizes can be confirmed by observing a cross section of the protective film or protective film-forming film.

[0128] (1.2.5 Coupling agent)

[0129] The protective film-forming film preferably contains a coupling agent (F). The inclusion of a coupling agent can improve the adhesion between the protective film and the workpiece while maintaining the heat resistance of the protective film after curing, and can also improve water resistance (resistance to moist heat). Silane coupling agents are preferred as coupling agents due to their versatility and cost advantages.

[0130] Examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-(methacryloxypropyl)trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfide, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazolesilane. These silane coupling agents may be used alone or in combination of two or more.

[0131] When the total weight of the protective film-forming film composition is 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.

[0132] (1.2.6 Colorants)

[0133] The protective film-forming film preferably contains a colorant (G). This shields the backside of the workpiece, such as a chip, thereby shielding it from various electromagnetic waves generated within electronic devices and reducing malfunctions of the workpiece, such as the chip. Furthermore, if any residue of the protective film-forming film adheres to the tension roller, it can be immediately detected with the naked eye.

[0134] As the colorant (G), for example, known colorants such as inorganic pigments, organic pigments, and organic dyes can be used. In the present embodiment, inorganic pigments are preferred.

[0135] As inorganic pigments, for example, 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, ATO (antimony tin oxide) pigments etc. can be listed. Among them, carbon black is particularly preferably used. Carbon black can block electromagnetic waves of a wider wavelength range.

[0136] The amount of colorant (especially carbon black) added to 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, the content of the colorant is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 4 parts by mass, based on the total weight of the protective film-forming film composition being 100 parts by mass.

[0137] The average particle size of the colorant (especially carbon black) is preferably 1 to 500 nm, particularly preferably 3 to 100 nm, and further preferably 5 to 50 nm. When the average particle size of the colorant is within the above range, it is easy to control the light transmittance within the desired range.

[0138] (1.2.7 Other additives)

[0139] The protective film-forming film composition may contain other additives such as a photopolymerization initiator, a crosslinking agent, a plasticizer, an antistatic agent, an antioxidant, a getter, a tackifier, and a release agent, within a range not impairing the effects of the present invention.

[0140] In this embodiment, the content of the stripping agent is preferably less than 0.00099 parts by mass based on 100 parts by mass of the total weight of the protective film-forming film composition. Excessive amounts of the stripping agent tend to reduce the reliability of adhesion between the protective film and the workpiece. Examples of the stripping agent include alkyd stripping agents, silicone stripping agents, fluorine-based stripping agents, unsaturated polyester-based stripping agents, polyolefin-based stripping agents, and wax-based stripping agents.

[0141] (1.2.8 Control of peeling force and adhesive force of protective film forming film)

[0142] As described above, this embodiment is characterized by controlling the peeling force F1 when peeling the first release film 12 from the protective film-forming film 11, the peeling force F2 when peeling the second release film 13 from the protective film-forming film 11, and the adhesion force F3 of the protective film-forming film 11 to the stainless steel plate within predetermined ranges. As described above, these specific peeling characteristics can be controlled by the types and amounts of the components constituting the protective film-forming film.

[0143] If the weight-average molecular weight of the polymer component (A) is low, the peeling force tends to increase. If the glass transition temperature of the polymer component (A) is low, the peeling force tends to increase. In addition, if low molecular weight compounds are used as the curable component (B), curing agent (C), curing accelerator (D), or energy-ray curable component, the peeling force tends to increase. If the amount of filler (E) added is large, the peeling force tends to decrease.

[0144] The peeling force can also be controlled by partially curing the protective film-forming film. For example, the peeling force can be reduced by partially curing the curable component (B).

[0145] Furthermore, the peeling forces F1 and F2 can be controlled by peeling the first peeling film 12 and the second peeling film 13. This will be described later.

[0146] (2. Sheet for forming protective film)

[0147] like Figure 1 As shown, the protective film forming film is wound and stored in the form of a three-layer protective film forming sheet 10 with the protective film forming film 11 sandwiched between two release films (a first release film 12 and a second release film 13) before use. The release films are peeled off when the protective film forming film is used.

[0148] The protective film forming sheet is long and is wound into a roll for storage and transportation. As such a protective film forming sheet, a protective film forming sheet is also known in which a protective film forming film is punched into a shape roughly the same as the workpiece. The protective film forming film 16 punched into a predetermined closed shape in the protective film forming sheet is sandwiched between two release films (12, 13) ( Figure 2 ).

[0149] The first release film and the second release film can be composed of a single layer (single layer) or two or more layers of a substrate. From the perspective of controlling the release properties, the surface of the substrate can be subjected to a release treatment. That is, the surface of the substrate can be modified, or a layer made of a material different from that of the substrate can be formed on the surface of the substrate. In this embodiment, it is preferred that the first release film and the second release film have a substrate and a release agent layer. By having a release agent layer, it is easy to control the physical properties of the surface of the first release film and the second release film on which the release agent layer is formed. In this embodiment, after applying a coating agent containing a release agent layer composition described later on one side of the substrate, the coating film is dried and cured to form the release agent layer. In this way, the first release film and the second release film can be obtained.

[0150] (2.1 First Release Film 12)

[0151] The thickness of the first release film 12 is not particularly limited, but is preferably 30 to 100 μm, more preferably 40 to 80 μm, and even more preferably 45 to 70 μm.

[0152] By setting the lower limit of the thickness of the first release film 12 to the above value, it is possible to prevent the cutter from penetrating the first release film 12 and cutting the first release film 12 when the protective film-forming film is cut with a cutter. In addition, 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 rollers such as guide rollers within the apparatus before being transported to the next step. However, by setting the upper limit of the thickness of the first release film 12 to the above value, it is possible to prevent the protective film-forming film 11 from peeling off from the first release film 12.

[0153] The thickness of the first release film 12 refers to the thickness of the entire first release film. For example, the thickness of a first release film composed of a plurality of layers refers to the total thickness of all layers constituting the first release film.

[0154] As the base material of the first peeling film 12, resin film and paper can be listed. As the resin of the resin film, polyethylene terephthalate, polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polybutylene terephthalate, polyurethane, ethylene-vinyl acetate copolymer, ionomer resin, ethylene (meth) acrylic acid copolymer, polystyrene, polycarbonate, fluororesin, low-density polyethylene, linear low-density polyethylene and triacetyl cellulose can be listed. As paper, high-quality paper, coated paper (coat paper), glassine and laminated paper can be listed. These base materials can be used alone or in combination. Among them, polyethylene terephthalate film is preferred from the perspective of being cheap and having rigidity.

[0155] At least one surface of the first release film 12 (the surface laminated with the protective film-forming film 11) may be subjected to a release treatment using a release agent layer composition. The thickness of the release agent layer is preferably 30 nm to 200 nm, more preferably 50 nm to 180 nm.

[0156] 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, even 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 a surface can be deformed. 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, it is possible to suppress the occurrence of lifting (peeling of approximately 1 to 4 mm) between the protective film-forming film 11 and the first release film 12 when the die is pressed and then pulled up during the punching process. This is believed to be because the surface of the first release film 12 is relatively soft, and even in the presence of compression due to the die and decompression due to its release, the surface of the first release film follows the deformation of the protective film-forming film. By suppressing the occurrence of lifting, defects in the waste removal process can be further reduced. The lower limit of the surface elastic modulus of the surface of the first peeling film 12 in contact with the protective film forming film 11 is not particularly limited, but if the surface elastic modulus is too low, the peeling force may sometimes increase, so it is preferably 3 MPa or more, more preferably 4 MPa or more, and particularly preferably 5 MPa or more.

[0157] 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 pressed and pulled away by the cantilever to generate a force curve. The resulting force curve is fitted using the JKR theory to determine the elastic modulus, which is the surface elastic modulus of the present invention. The specific measurement method will be described in detail in the Examples below.

[0158] The first release film 12 can be easily obtained by subjecting one surface of the substrate to a release treatment. Preferred release agent compositions for the release layer used in this release treatment include, for example, alkyd release agents, silicone release agents, fluorine release agents, unsaturated polyester release agents, polyolefin release agents, and wax release agents. Silicone release agents are preferred, and a composition containing a silicone release agent and a heavy-duty release additive is particularly preferred.

[0159] As the silicone-based release agent, a silicone release agent containing silicone having dimethylpolysiloxane as a basic skeleton can be used.

[0160] The silicone can be any of addition-reaction type, condensation-reaction type, and energy-ray curing types such as UV-curable and electron-beam curable, but addition-reaction type silicone is preferred. Addition-reaction type silicones offer high reactivity and excellent productivity, and compared to condensation-reaction type silicones, they have advantages such as minimal variation in release strength after production and no curing shrinkage.

[0161] Specific examples of addition-reaction silicones include organopolysiloxanes having two or more alkenyl groups with 2 to 10 carbon atoms, such as vinyl, allyl, propenyl, and hexenyl, at the molecular ends and / or in the side chains. From the perspective of reducing the surface elastic modulus, it is preferable that the number of alkenyl groups in the addition-reaction silicone be small.

[0162] When the total weight of the release agent layer composition (excluding the catalyst described below) is 100 parts by mass, the content of the 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.

[0163] When using such an addition reaction type silicone, it is preferred to use a crosslinking agent and a catalyst simultaneously.

[0164] Examples of the crosslinking agent include organopolysiloxanes having at least two silicon atoms bonded to hydrogen atoms in one molecule. From the perspective of reducing the surface elastic modulus, the crosslinking agent content in the release agent layer composition is preferably low.

[0165] Specific examples of the crosslinking agent include dimethylhydrogensiloxane-methylhydrogensiloxane copolymers terminated with dimethylhydrogensiloxane, trimethylhydrogensiloxane-methylhydrogensiloxane copolymers terminated with trimethylhydrogensiloxane, and poly(hydrogensilsesquioxane).

[0166] Examples of the catalyst include fine-particle platinum, fine-particle platinum adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, and platinum group metal compounds such as palladium and rhodium.

[0167] By using such a catalyst, the curing reaction of the release agent layer composition can be carried out more efficiently.

[0168] From the perspective of setting the surface elastic modulus within the above range and setting the peeling force F1 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.

[0169] The heavy release additive is used to increase the release force F1 when the first release film 12 is released from the protective film-forming film 11. Examples of the heavy release additive include silicone resins and organosilanes such as silane coupling agents, and silicone resins are preferred.

[0170] As the silicone resin, for example, MQ resin containing a monofunctional siloxane unit [R3SiO 1 / 2 ] and the M unit as a tetrafunctional siloxane unit [SiO 4 / 2 ] Q unit. Furthermore, the three Rs in the M unit each independently represent a hydrogen atom, a hydroxyl group, or an organic group. From the perspective of easily suppressing silicone migration, at least one of the three Rs in the M unit is preferably a hydroxyl group or a vinyl group, more preferably a vinyl group. From the perspective of reducing the surface elastic modulus, the content of the silicone resin (particularly the MQ resin) in the release agent layer composition is preferably low.

[0171] The content of the heavy-duty release 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, based on 100 parts by mass of the total weight of the release agent layer composition (excluding the catalyst).

[0172] From the perspective of adjusting viscosity and improving coating properties on substrates, the release agent layer composition is preferably used as a coating agent containing a diluent solvent in addition to the various active ingredients described above. In this specification, "active ingredient" refers to the components contained in the coating agent containing the target composition, excluding the diluent solvent.

[0173] Examples of the dilution solvent include organic solvents such as 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 dilution solvents may be used alone or in combination of two or more.

[0174] The active ingredient (solid content) concentration of the coating agent containing the release agent layer composition is preferably 0.3 to 10% by mass, more preferably 0.5 to 5% by mass, and even more preferably 0.5 to 3% by mass.

[0175] The release agent layer composition may contain additives commonly used in release agent layers, as long as the effects of the present invention are not impaired. Examples of such additives include dyes and dispersants.

[0176] (2.2 Second Release Film 13)

[0177] The thickness of the second release film 13 is not particularly limited, but from the perspective of ease of release, it is preferably equal to or less than the thickness of the first release film 12, and more preferably thinner than the first release film 12. Therefore, the thickness of the second release film 13 is preferably 10 to 75 μm, more preferably 18 to 60 μm, and even more preferably 24 to 45 μm.

[0178] The material of the base material used for the second release film 13 is the same as that of the first release film 12. The release agent layer composition of the second release film 13 can be selected from the materials exemplified for the first release film 12, as long as the relationship between F1 and F2 is satisfied. However, the materials exemplified as heavy release additives are preferably present in a lower content than in the first release film 12, or are not present at all.

[0179] Furthermore, since the release force can be suppressed to a low level by adding silicone oil to the release agent layer composition, silicone oil may be used to adjust the release force.

[0180] (2.3 Control of the peeling force of the peeling film)

[0181] The peeling forces F1 and F2 can be controlled by the following various factors in addition to the composition of the protective film-forming film.

[0182] Type of resin material as the main component of the release agent layer composition (silicone-based, fluorine-based, long-chain alkyl-based, etc.)

[0183] The molecular weight of the resin material as the main component of the release agent layer composition

[0184] Crosslinking density of the release agent layer composition (this crosslinking density is also affected by the type of crosslinking agent, its content before the crosslinking reaction, the density of functional groups reactive with the crosslinking agent, etc.)

[0185] Additional components contained in the release agent layer composition (specifically, low molecular weight substances that are not cross-linked and / or are not easily cross-linked)

[0186] ·Thickness of release agent layer

[0187] ·Surface roughness of the surface of the release agent layer that contacts the protective film-forming film

[0188] Thickness of the resin film as the base material

[0189] Temperature when the release film and protective film are bonded together

[0190] · Pressure when the release film and protective film are bonded together

[0191] · Roller speed when laminating the release film and protective film

[0192] (3. Method for Manufacturing Protective Film-Forming Sheet)

[0193] The method for producing the protective film-forming film is not particularly limited. The film can be produced using the protective film-forming film composition described above or a composition obtained by diluting the protective film-forming film composition with a solvent (a coating agent containing the protective film-forming film composition). The coating agent can be prepared by mixing the components constituting the protective film-forming film composition using a known method.

[0194] The protective film-forming sheet 10 of this embodiment can be obtained by applying the obtained coating agent to the release surface of the first release film 12 using a coating machine such as a roll coater, a knife coater, a roll knife coater, an air knife coater, a die coater, a rod coater, a gravure coater, or a curtain coater, and then laminating the second release film 13 on the exposed surface of the protective film-forming film 11. The lamination order is not particularly limited, and the coating agent can also be applied to the second release film. In addition, the coating agent can also be applied to another resin film and dried, and the obtained protective film-forming film can be transferred to the first release film or the second release film. Furthermore, after laminating these films, heating and pressurization can also be performed using a hot roller or the like. From the perspective of operability during manufacturing, it can be applied to the release surface of the first release film 12 and dried, and then the process release film can be laminated on the exposed surface of the protective film-forming film 11, and then the process release film can be peeled off and the second release film 13 can be attached.

[0195] (4. Method for Manufacturing Punched Protective Film-Forming Sheet)

[0196] In the protective film forming sheet 10 of this embodiment, the protective film forming film 11 is preferably punched into a predetermined shape. In other words, the protective film forming sheet is preferably provided with a cutout 14 so that a portion of the protective film forming sheet 10 has a predetermined closed shape when viewed from above.

[0197] A method of punching the protective film-forming sheet 10 to obtain a protective film-forming film punched into a predetermined closed shape on the first release film 12 will be described.

[0198] (4.1 Punching process)

[0199] First, prepare Figure 1The protective film forming sheet 10 shown is not punched. Using a punch (not shown), a cut 14 is cut from the second release film 13 side of the protective film forming sheet 10 so as to penetrate the second release film 13 and the protective film forming film 11 and reach a portion of the surface of the first release film 12. The operation of cutting so as to reach a portion of the surface without completely cutting is called a half-cut. As a result, a cut 14 is formed in a portion of the surface of the protective film forming sheet 10 in a manner having a predetermined closed shape (see Figure 2 、 Figure 3 Here, when the protective film-forming film is transferred onto a semiconductor wafer, the predetermined closed shape is substantially the same as the shape of the wafer. Specifically, the cutout 14 is formed to have a shape substantially the same as the shape of the workpiece to which the protective film-forming film 11 is attached or the shape of the area where the protective film is to be formed. This process is referred to as a "punching process."

[0200] The punching step separates the laminate of the second release film 13 and the protective film-forming film 16, which are punched into a predetermined closed shape, and the laminate of the second release film 13 and the protective film-forming film 16, which are punched into a predetermined closed shape, and the laminate of the second release film 13 and the protective film-forming film 16, which are punched into a predetermined closed shape, at multiple locations along the longitudinal direction of the protective film-forming sheet 10.

[0201] (4.2 Waste Removal Process)

[0202] like Figure 4 As shown, in the waste removal process, the second release film 13 (i.e., the second release film in contact with the useless portion 17 and the second release film in contact with the punched protective film forming film 16) and the useless portion 17 are removed, leaving the punched protective film forming film 16 remaining on the first release film 12. At this time, the second release film 13 that has been completely cut by the punching process is reattached using a long adhesive tape, making it easy to remove the second release film 13. Figure 5 As shown, the peeled useless part 17 passes through the tension roller 19 and is finally wound on the waste roller 20.

[0203] According to this embodiment, since the peeling forces F1, F2 and adhesion force F3 are designed in a manner that meets the prescribed necessary conditions, when the second peeling film 13 and the useless portion 17 of the protective film-forming film are wound, even if the surface of the protective film-forming film side contacts the stainless steel tension roller 19, the protective film-forming film will not remain attached to the tension roller 19, and the second peeling film 13 and the useless portion 17 of the protective film-forming film can be wound on the waste roller 20.

[0204] As a result of the waste material removal step, the protective film-forming film 16 punched into a predetermined closed shape remains on the first release film 12. Then, the exposed protective film-forming film 16 is attached to a predetermined workpiece.

[0205] When removing the second release film from the punched protective film-forming film 16 , satisfying the relationship F1 > F2 facilitates removal of the second release film, and ensures that the punched protective film-forming film 16 remains on the first release film 12 .

[0206] The punched protective film-forming sheet 10 can be wound into a roll for storage and transportation.

[0207] (5. Workpiece processing method)

[0208] As an example of a method for processing a workpiece using the punched protective film forming sheet of this embodiment, a method for manufacturing a package in which a chip with a protective film obtained by processing a wafer with a protective film formed thereon is arranged on a substrate will be described.

[0209] The method for manufacturing a package includes at least the following steps 1 to 9.

[0210] Step 1: Punching the protective film forming sheet 10

[0211] Step 2: Step of removing the second release film 13 and the unnecessary portion 17 of the protective film-forming film (waste removal step)

[0212] Step 3: The removed second release film 13 and the unnecessary portion 17 of the protective film forming film are passed through the tension roller 19 and wound up.

[0213] Step 4: Step of attaching the punched protective film forming film 16 of the protective film forming sheet 10 to the back surface of the wafer

[0214] Step 5: The process of forming the attached protective film into a protective film

[0215] Step 6: Step of peeling the first peeling film 12 from the protective film or protective film-forming film

[0216] Step 7: Singulate the wafer having a protective film or protective film forming film on the back to obtain a plurality of chips with a protective film or protective film forming film.

[0217] Step 8: Place the chip with the protective film or protective film forming film on the substrate

[0218] Step 9: Step of heating the chip with the protective film or protective film-forming film disposed on the substrate and the substrate

[0219] Steps 1 to 3 are as described above. Step 5 can be performed before step 6 or after any of steps 6 to 9. That is, the step of converting the protective film forming film into a protective film can be performed at any stage after the protective film forming film is attached to the wafer.

[0220] A method for manufacturing the device including the above-mentioned steps 1 to 9 will be described with reference to the drawings.

[0221] like Figure 7 As shown, the protective film-forming film 16 of the protective film-forming sheet 10 is attached to the back surface of the wafer 21 (step 4). Then, the attached protective film-forming film 16 is converted into a protective film to form a protective film 32 (step 5), thereby obtaining a wafer with a protective film. When the protective film-forming film 16 is thermosetting, the protective film-forming film 16 can be heated at a predetermined temperature for an appropriate time. Alternatively, when the protective film-forming film 16 is energy-ray-curable, an energy-ray-transmitting film can be used as the first release film 12, and the energy rays can be incident from the first release film 12 side.

[0222] Furthermore, the protective film forming film 16 may be cured after the dicing step described later, or the protective film forming film 16 may be cured after the chip with the protective film forming film is picked up from the dicing sheet.

[0223] Then, the wafer 21 with the protective film is transferred to a known cutting blade 22, and the wafer 21 with the protective film is cut, as shown in FIG. Figure 8 As shown, a chip 31 with a protective film 32 (a chip 30 with a protective film) is obtained (step 7). Then, the dicing sheet 22 is expanded in the planar direction as needed, and the chip 30 with a protective film is picked up from the dicing sheet 22 using a suction nozzle (not shown).

[0224] The picked-up chip 30 with a protective film may be transported to the next process, or may be temporarily stored on a tray, tape, or the like and transported to the next process after a predetermined period of time.

[0225] like Figure 9 As shown, the chip 30 with a protective film, which is being transported to the next step, is transferred to the substrate 50 by the nozzle. The terminal portion on the substrate is released from the nozzle and arranged in a position where the convex electrodes 33 such as bumps can be connected to the terminal portion such as pads (step 8). At this time, other chips other than the chip 30 with a protective film can also be mounted on the substrate 50. Therefore, multiple chips can be mounted on the substrate.

[0226] The chip with the protective film placed at a predetermined position on the substrate is subjected to a heat treatment (reflow treatment) (step 9). The reflow treatment conditions are preferably, for example, a maximum heating temperature of 180 to 350° C. and a reflow time of 2 to 10 minutes.

[0227] During the reflow process, the bump electrodes 33 of the chip with protective film 30 are melted and electrically and mechanically connected to the terminal portion on the substrate, and the chip with protective film 30 is mounted on the substrate.

[0228] As mentioned above, although embodiment of this invention was demonstrated, this invention is not limited at all to the said embodiment, It can change in various forms within the scope of this invention.

[0229] Example

[0230] Hereinafter, the present invention will be described in further detail using examples, but the present invention is not limited to these examples.

[0231] (Manufacture of Protective Film-Forming Sheet)

[0232] [First release film (heavy release film)]

[0233] <Releasable Agent Layer Composition>

[0234] The following release agent layer composition raw materials were prepared.

[0235] A silicone-based release agent containing an organopolysiloxane having a vinyl group and an organopolysiloxane having a hydrosilyl group (manufactured by Dow Corning Toray Co., Ltd., BY24-561, solid content 30% by mass)

[0236] Dimethylpolysiloxane (weight average molecular weight: 2000) (manufactured by Shin-Etsu Chemical Co., Ltd., X-62-1387, solid content: 100% by mass)

[0237] MQ resin having a vinyl group as a heavy release additive (manufactured by Dow Corning Toray Co., Ltd., SD-7292, solid content 71% by mass)

[0238] Platinum (Pt) catalyst (manufactured by Dow Corning Toray Co., Ltd., SRX-212, solid content: 100% by mass)

[0239] The above raw materials were added to a mixed solvent of toluene and methyl ethyl ketone (toluene / methyl ethyl ketone = 1 / 1 (mass ratio)) at the blending ratio (solid content conversion) listed in Table 1 to adjust the total solid content to 2 mass %, thereby preparing a coating agent containing a composition for a release agent layer.

[0240] <Manufacturing of the First Release Film>

[0241] A coating agent containing a release agent layer composition was applied to a PET film (manufactured by Mitsubishi Chemical Corporation, trade name: DIAFOIL (registered trademark) T-100, thickness: 50 μm) so that the film thickness after drying was 0.15 μm, and the film was heated and dried to form a release agent layer on the PET film to produce a first release film (heavy release film).

[0242] <Measurement of Surface Elastic Modulus>

[0243] The surface elastic modulus of the release-treated surface of the obtained first release film was measured in the following manner.

[0244] A cantilever of silicon nitride material (manufactured by Bruker Corporation, trade name: MLCT, tip radius: 20 nm, resonance frequency: 125 kHz, spring constant: 0.6 N / m) was set on an atomic force microscope (manufactured by Bruker Corporation, MultiMode 8). The manufactured first peeling film was placed on the atomic force microscope, and the surface of the peeling agent layer of the manufactured first peeling film was pressed and pulled off by the cantilever with a pressing amount of 2 nm and a scanning speed of 10 Hz. This operation was carried out at 23°C. The force curve obtained by this operation was fitted based on the JKR theoretical formula to calculate the surface elastic modulus. For the surface elastic modulus, 4096 points were measured in 1 μm×1 μm on the surface of the peeling agent layer of the first peeling film, and the average of these values was taken and rounded off to one decimal place to obtain the surface elastic modulus (MPa). The results are shown in Table 1.

[0245] [Table 1]

[0246]

[0247] [Release film for process]

[0248] 33 parts by mass (in terms of solid content) of a solvent-based silicone release agent containing a polyorganosiloxane having a vinyl group and an organohydrogenpolysiloxane (trade name "KS-835", solid content: 30% by mass, viscosity: 5000 mPa·s, manufactured by Shin-Etsu Chemical Co., Ltd.) and 1.0 part by mass (in terms of solid content) of a platinum catalyst (trade name "PL50T", manufactured by Shin-Etsu Chemical Co., Ltd.) were diluted with toluene solvent so that the solid content concentration was 2.0% by mass to prepare a coating agent containing a composition for a release agent layer.

[0249] The coating agent was applied to a 38 μm thick PET film substrate (trade name: DIAFOIL (registered trademark) T-100, manufactured by Mitsubishi Chemical Corporation) to a film thickness of 0.15 μm after drying, and then dried at 150° C. for 30 seconds to obtain a process release film.

[0250] [Second release film (light release film)]

[0251] The following release films A to C were prepared.

[0252] Release film A: "SP-PET381130 (thickness: 38 μm)" manufactured by Lintec Corporation

[0253] Release film B: "SP-PET381031 (thickness: 38 μm)" manufactured by Lintec Corporation

[0254] Furthermore, a release film C was produced in the following manner.

[0255] In the same manner as for the production of the first release film, a coating agent containing the release agent layer composition at the blending ratio shown in Table 1 was prepared. The coating agent containing the release agent layer composition was applied to a PET film (manufactured by Mitsubishi Chemical Corporation, trade name: DIAFOIL (registered trademark) T-100, thickness: 38 μm) to a film thickness of 0.15 μm after drying. The coating agent was then heated and dried to form a release agent layer on the PET film, producing Release Film C (light release film). The release agent layer of Release Film C was the same as that of the first release film, but the application conditions were different, and the PET film was thinner, resulting in lighter release properties than the first release film. Table 3 shows the second release films used in the Examples and Comparative Examples.

[0256] [Coating agent containing protective film-forming composition]

[0257] The following components were mixed at the blending ratio (solid content conversion) shown in Table 2, and diluted with methyl ethyl ketone so that the solid content concentration became 50% by mass to prepare a coating agent.

[0258] (A) Polymer component

[0259] (A-1) A (meth)acrylate copolymer (weight average molecular weight: 400,000, glass transition temperature: -1°C) prepared by copolymerization 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.

[0260] (A-2) A (meth)acrylate copolymer (weight average molecular weight: 450,000, glass transition temperature: 2° C.) prepared by copolymerizing 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.

[0261] (B) Curable component (thermosetting component)

[0262] (B-1) Bisphenol A type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER828, epoxy equivalent weight 184 to 194 g / eq)

[0263] (B-2) Acrylic rubber microparticle-dispersed bisphenol A type liquid epoxy resin (manufactured by Nippon Shokubai Co., Ltd., BPA328, epoxy equivalent weight 230 g / eq, acrylic rubber content 20 phr)

[0264] (B-3) Dicyclopentadiene epoxy resin (manufactured by DIC Corporation, EPICLON HP-7200HH, softening point 88-98°C, epoxy equivalent 255-260 g / eq)

[0265] (C) Curing agent: dicyandiamide (manufactured by Mitsubishi Chemical Corporation, DICY7)

[0266] (D) Curing accelerator: 2-phenyl-4,5-dihydroxymethylimidazole (manufactured by SHIKOKU CHEMICALS CORPORATION, CUREZOL 2PHZ)

[0267] (E) Filling material

[0268] (E-1) Epoxy-modified spherical silica filler (manufactured by Admatechs, SC2050MA, average particle size 0.5 μm)

[0269] (E-2) Silica filler ("YC100C-MLA" manufactured by Admatechs, average particle size 0.1 μm)

[0270] (F) Silane coupling agent: γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM403, methoxy equivalent weight: 12.7 mmol / g, molecular weight: 236.3)

[0271] (G) Colorant: Carbon black (manufactured by Mitsubishi Chemical Corporation, MA600B, average particle size 28 nm)

[0272] [Table 2]

[0273]

[0274] A coating agent containing the prepared protective film-forming film composition was applied to the release-treated surface of the first release film and dried at 100°C for 2 minutes to form a 20 μm thick protective film-forming film. The process release film was then attached to the protective film-forming film to form a laminate of first release film / protective film-forming film / process release film. The attachment conditions were a temperature of 60°C, a pressure of 0.4 MPa, and a speed of 1 m / min. The laminate was allowed to stand in this state for 48 hours at 23°C and 50% RH.

[0275] Next, a second release film (any of the above-mentioned A to C) was attached to the exposed protective film-forming film using the release film for the peeling step, yielding a protective film-forming sheet with release films formed on both sides of the protective film-forming film. The attachment conditions were a temperature of 60°C, a pressure of 0.6 MPa, and a speed of 1 m / min. The protective film-forming sheet was then cut to a width of 208 mm and wound into a roll of 50 meters.

[0276] The following measurements and evaluations were performed using the obtained protective film-forming sheet.

[0277] [Peeling force F1 when peeling the first peeling film from the protective film-forming film]

[0278] The second release film was peeled off from the resulting protective film-forming sheet. The exposed surface of the protective film-forming film was then attached to the good-adhesive surface of 25 μm-thick high-adhesive PET (PET25A-4100 manufactured by TOYOBO Co., Ltd.) by heat lamination (70°C, 1 m / min) to create a laminate sample. The laminate sample was cut into 100 mm widths to create a measurement sample. The back of the first release film of the measurement sample was secured to a rigid support plate using double-sided tape.

[0279] A universal tensile testing machine (manufactured by Shimadzu Corporation, product name

[0280] Using a 180° peel angle and a peel rate of 1 m / min, a protective film-forming film / high-adhesion PET composite (integrated) was peeled from a first release film using a AUTOGRAPH (registered trademark) AG-IS. The load applied during this process was measured. The total measurement distance was 100 mm. The average of the measured values over the entire 80 mm distance, excluding the first and last 10 mm, was converted to mN / 100 mm to form the peel force F1. The results are shown in Table 3.

[0281] [Peeling force F2 when peeling the second peeling film from the protective film-forming film]

[0282] The obtained protective film-forming sheet was cut into a width of 100 mm to prepare a measurement sample. The back surface of the first release film of the measurement sample was fixed to a hard support plate using a double-sided tape.

[0283] A universal tensile testing machine (manufactured by Shimadzu Corporation, product name

[0284] The second release film was peeled off from the sample for measurement using the same conditions as those for measuring F1. The load at this time was measured as the peel force F2. The results are shown in Table 3.

[0285] [Adhesion force F3 between protective film-forming film and stainless steel plate]

[0286] The protective film-forming film was exposed from the protective film-forming sheet in the following manner, the protective film-forming film was attached to a stainless steel plate, and the adhesive strength was measured.

[0287] <Fixing the Protective Film Forming Film on the Adhesive Tape>

[0288] I. The second release film of the protective film-forming sheet having a three-layer structure of second release film / protective film-forming film / first release film is peeled off.

[0289] II. An adhesive tape manufactured by Lintec Corporation (product name PET50PL-Shin: acrylic adhesive layer / 50 μm PET substrate) was attached to the exposed protective film-forming film at 23°C to prepare a laminate sample of "PET substrate / acrylic adhesive / protective film-forming film / first release film".

[0290] III. Cut the laminate sample into strips 25 mm wide and 250 mm long.

[0291] <Fixing the Protective Film Forming Film on the Stainless Steel Plate>

[0292] I. A stainless steel plate (SUS304#600 single-sided 600HL 0.5 mm thick × 70 mm × 150 mm) was cleaned with toluene and methyl ethyl ketone and then dried.

[0293] II. The first release film is peeled off from the laminate of "PET substrate / acrylic adhesive / protective film-forming film / first release film" to expose the protective film-forming film.

[0294] III. The exposed protective film-forming film was laminated on a stainless steel plate and bonded at 23° C. using a 2 kg roller.

[0295] The sheets were allowed to stand without heating, and after 2 minutes (±20 seconds) had passed since the attachment, the adhesive strength was measured using the following measurement method.

[0296] The peel force was measured using a universal tensile tester (manufactured by Shimadzu Corporation, product name "AUTOGRAPH AG-IS") over a measurement distance of 70 mm at a peel rate of 300 mm / min, a temperature of 23°C, and a peel angle of 180°. The average of the measured values over a 50 mm distance, excluding the first and last 10 mm of the measurement distance, was converted to mN / 100 mm to represent the adhesion force F3 of the protective film-forming film to the stainless steel plate. This value was used to calculate F2 / F3.

[0297] [Stability of waste removal process]

[0298] Using RAD-3600F / 12 manufactured by Lintec Corporation with specifications for 200 mm wafers, the die was inserted from the second release film side of the protective film forming sheet (total length 50 m, width 208 mm), and the protective film forming film and the second release film were punched out into a circular shape (inner diameter 198 mm). The protective film forming film 16 punched out into a circular shape remained on the first release film 12, and was then cut into a circular shape. Figure 4 As shown in the figure, the second release film 13 and the useless portion 17 around the protective film forming film 16 that has been punched into a circular shape are removed (waste removal step). At this time, the second release film 13 that has been completely cut after the punching process is reattached using a long adhesive tape 18, and then the second release film 13 is removed. Then, as shown in the figure, Figure 5 As shown, the removed second release film 13 and the unnecessary portion 17 are finally wound around a waste roller 20 via a tension roller 19 .

[0299] While winding 10 m of the second release film and the unused portion, the number of times the protective film-forming film remained attached to the tension roller was counted and evaluated according to the following criteria. If the protective film-forming film remained attached to the tension roller, the system was stopped (waste removal was stopped) and the tension roller was wiped and cleaned with methyl ethyl ketone.

[0300] A: 0 times

[0301] B: 1 time

[0302] C: 2 to 3 times

[0303] D: 4 or more times

[0304] The above results are shown in Table 3.

[0305] [Table 3]

[0306]

[0307] Units of peel force and adhesion force: mN / 100mm

[0308] As shown in Table 3, by designing the film so that the peeling forces F1 and F2 between the protective film-forming film and the release film and the adhesion force F3 of the protective film-forming film to the stainless steel plate meet the prescribed necessary conditions, when the second release film and the unnecessary portion are wound up, even if the surface on the protective film-forming film side contacts the stainless steel tension roller, the protective film-forming film will not remain attached to the roller, and the second release film and the unnecessary portion can be stably wound up on the waste removal roller. Therefore, there is no need to stop the waste removal, and the production efficiency is improved.

[0309] Industrial Applicability

[0310] As described above, according to the present invention, a protective film-forming sheet capable of sufficiently suppressing stoppage of waste material removal and a method for producing the same can be provided.

Claims

1. A sheet for forming a protective film, which is a long sheet and comprises: A protective film-forming film for forming a protective film, a first release film provided on one surface of the protective film-forming film, and a second release film provided on the other surface of the protective film-forming film, wherein The protective film-forming film is composed of a protective film-forming film composition, and the protective film-forming film composition contains at least an acrylic resin, an epoxy resin, and a filler. When the peeling force when peeling the first peeling film from the protective film-forming film is F1 and the peeling force when peeling the second peeling film from the protective film-forming film is F2, the relationship F1>F2 is satisfied. When the adhesion of the protective film-forming film to the stainless steel plate is defined as F3, the relationship F2 / F3≥0.13 is satisfied. F2 is 30mN / 100mm or more, F3 is less than 500mN / 100mm, The F1 and F2 are measured under the conditions of a peeling angle of 180° and a peeling speed of 1 m / min. The F3 is measured under the measurement conditions of a peeling speed of 300 mm / min, a temperature of 23° C., and a peeling angle of 180°.

2. The protective film-forming sheet according to claim 1, wherein The weight of the epoxy resin that is liquid at room temperature contained in the protective film-forming film composition is 12 parts by mass or less, based on 100 parts by mass of the total weight of the protective film-forming film composition constituting the protective film-forming film.

3. The protective film-forming sheet according to claim 1 or 2, wherein When the total weight of the protective film-forming film composition constituting the protective film-forming film is 100 parts by mass, the weight of the filler contained in the protective film-forming film composition is less than 55 parts by mass.

4. The protective film-forming sheet according to claim 1 or 2, wherein The protective film forming sheet has a cutout formed therein so that a portion of the protective film forming sheet has a predetermined closed shape when the protective film forming sheet is viewed from above. The incision penetrates the protective-film-forming film in the thickness direction of the protective-film-forming sheet and reaches a portion of the first release film.

5. The protective film-forming sheet according to claim 3, wherein The protective film forming sheet has a cutout formed therein so that a portion of the protective film forming sheet has a predetermined closed shape when the protective film forming sheet is viewed from above. The incision penetrates the protective-film-forming film in the thickness direction of the protective-film-forming sheet and reaches a portion of the first release film.

6. A method for producing a punched protective film-forming sheet, comprising the step of forming a notch so that a portion of the protective film-forming sheet according to any one of claims 1 to 5 has a predetermined closed shape. The incision penetrates the protective-film-forming film in the thickness direction of the protective-film-forming sheet and reaches a portion of the first release film.

Images