TWI888619B - Sheet for forming protective film and method for producing the same - Google Patents

Abstract

The present invention provides a protective film forming sheet and a method for manufacturing the same, which can fully suppress waste removal defects even when the incision width is narrow during punching. The protective film forming sheet is a long sheet and has a protective film forming film and a first peeling film provided on one surface of the protective film forming film. The protective film forming sheet is characterized in that the adhesion of two protective film forming films after being attached at 23°C with a load of 2kgf for 2 minutes is 19N/25mm or less.

Description

Sheet for forming protective film and method for producing the same

The present invention relates to a protective film forming sheet and a method for manufacturing the same. In particular, the present invention relates to a protective film forming sheet having a protective film forming 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 manufacturing the protective film forming sheet.

In recent years, semiconductor devices have been manufactured using a mounting method called flip chip bonding. In this mounting method, when mounting a semiconductor chip having a circuit surface with convex electrodes such as bumps, the circuit surface side of the semiconductor chip is reversed (face down) and bonded to the chip mounting portion. Therefore, the semiconductor device has a structure in which the back side of the semiconductor chip where no circuit is formed is exposed.

Therefore, in order to protect the semiconductor chip from impact during transportation, a hard protective film made of an organic material is usually formed on the back side of the semiconductor chip. To form this protective film, an uncured resin film (hereinafter referred to as 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.

As a product form of the protective film forming film, there is known a protective film forming sheet 10 having a double-layer structure in which a protective film forming film 11 is releasably stacked on a first peeling film 12 as shown in FIG1, or a protective film forming sheet 20 having a triple-layer structure in which a protective film forming film 11 is sandwiched between two peeling films (12, 13) as shown in FIG3. In addition, the above-mentioned protective film forming sheet is a long strip and is stored and transported in a roll shape. In this protective film forming sheet, the protective film forming film is sometimes pre-punched into a shape roughly the same as a workpiece (a general term for adherends such as semiconductor wafers) and attached to the workpiece. The punched protective film forming sheet is stacked with a protective film forming film 16 punched into a predetermined closed shape on the first release film 12 (Fig. 2), or sandwiched between two release films (12, 13) (Fig. 4).

The punched protective film forming sheet is manufactured by punching the protective film forming film into a predetermined closed shape using a punching die, and is used in a manner that removes the unnecessary portion 17 around the punched protective film forming film 16. In the case of a double-layered protective film forming sheet composed of the protective film forming film 11 and the first release film 12, the cut 14 is made in a manner that the protective film forming film 11 is completely punched into a predetermined closed shape and the first release film 12 is not completely punched, and the protective film forming film 16 of the predetermined closed shape remains on the first release film 12, and the unnecessary portion 17 around the edge is removed. In the case of a three-layer protective film forming sheet in which the protective film forming film 11 is sandwiched between two release films (12, 13), the protective film forming film 11 and the second release film 13 on one side are completely punched into a prescribed closed shape and the first release film 12 on the other side is not completely punched, and the incision 14 is cut so that the protective film forming film 16 of the prescribed closed shape remains on the first release film 12, and the useless portion 17 around the second release film 13 is removed.

The following is a detailed description of the case of a double-layer protective film forming sheet. As shown in FIG5 , a protective film forming sheet 10 composed of a protective film forming film 11 and a first release film 12 is punched by completely punching the protective film forming film 11 into a predetermined closed shape and not completely punching the first release film 12, thereby making a punched protective film forming sheet. This step is called a "punching step".

Then, in order to attach the punched protective film forming sheet to the workpiece, the useless portion 17 around the protective film forming film 16 punched into a predetermined closed shape is removed (Fig. 6). This step is called a "waste removal step". As a result, a laminate having a protective film forming film 16 punched into a predetermined closed shape on the first release film 12 that can be attached to the workpiece can be obtained.

In the case of a three-layer protective film forming sheet, the same as the case of a two-layer protective film forming sheet is used, except that another peeling film 13 (second peeling film 13) is provided on the protective film forming film 11 in the punching process step, and the second peeling film 13 is also completely punched into a prescribed closed shape, and the second peeling film 13 is removed in the waste material removal step.

As a protective film forming sheet, it is required to be able to perform the punching process step stably (operation stability). In particular, after the protective film forming film is punched, the waste material removal step of removing the useless part is required to have operational stability. More specifically, in the waste material removal step, it is required that the protective film forming film 16 that should be left is not accidentally peeled off from the first peeling film 12 together with the useless part 17 (hereinafter referred to as "waste material removal defect")

In order to solve the above problems, for example, Patent Document 1 proposes controlling the peeling force between the peeling film and the protective film forming film within a specified range.

[Prior art literature]

[Patent Literature]

Patent document 1: International publication WO2017/145735

If waste removal failure occurs, the production line needs to be stopped and the defective products need to be discarded, which reduces product productivity and increases costs. Therefore, it is required to further suppress waste removal failure.

The inventors of the present invention have further studied the causes of poor waste removal and obtained the following insights.

After the punching process and before the waste material removal process, the protective film forming sheet 10 passes through multiple rollers such as guide rollers for the purpose of controlling the tension of the protective film forming sheet. At this time, as shown in FIG. 7, the protective film forming sheet 10 is sometimes bent in such a way that the upper side of the cut 14 (the side where the punch enters) is the side of the roller 19. As a result of the bending, the width of the cut 14 becomes narrower, especially in the cut portion that is almost parallel to the short side direction of the sheet 10, and the protective film forming film 16 is squeezed and slightly deformed, which sometimes causes the adjacent protective film forming film 16 to contact and adhere to the useless part 17.

After passing through the roller 19, in most cases, the attachment portion of the protective film forming film 16 and the useless portion 17 will separate again, but sometimes they will not separate and remain attached. If waste material removal is performed with the protective film forming film 16 and the useless portion 17 attached, the protective film forming film 16 that should remain on the first peeling film 12 will be accidentally peeled off from the first peeling film 12 together with the useless portion 17 that should be removed, resulting in poor waste material removal.

The present invention is made in view of the above-mentioned actual situation, and its purpose is to provide a protective film forming sheet and a manufacturing method thereof that can fully suppress the defect of waste material removal even when the cut width is narrow during punching.

The scheme of the present invention is as follows.

(1) A protective film forming sheet, which is a long sheet and has a protective film forming film and a first release film provided on one surface of the protective film forming film, wherein the adhesion after two protective film forming films are attached at 23°C with a load of 2 kgf for 2 minutes is 19 N/25 mm or less.

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

(3) The protective film forming sheet according to (1) or (2), wherein a cut is formed on the protective film forming sheet 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, and the cut 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.

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

(5) A method for manufacturing a punched protective film forming sheet, comprising the step of forming a cut so that a portion of the protective film forming sheet described in (1) or (2) above has a predetermined closed shape, wherein the cut 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) The method for manufacturing a punched protective film-forming sheet according to (5), wherein the width of the cut at the interface between the protective film-forming film and the first release film is 8 μm or more.

According to the present invention, a protective film forming sheet and a method for manufacturing the same can be provided, which can fully suppress the defect of waste material removal even when the cut width is narrow during punching.

10: Sheet for forming protective film

11: Protective film forming film

12: First peeling membrane

13: Second peeling membrane

14: Incision

16: Protective film formed by punching process

17: Useless part

19: Roller

20: Sheet for forming protective film

21: Wafer

22: Cutting disc

30: Chip with protective film

31: Chip

32: Protective film

33: Convex electrode

50:Substrate

D: Width

Figure 1 is a schematic cross-sectional view of a protective film forming sheet according to an implementation scheme.

FIG2 is a schematic cross-sectional view showing the state of the protective film forming sheet of the embodiment after punching.

Figure 3 is a schematic cross-sectional view of a protective film forming sheet according to another embodiment.

FIG4 is a schematic cross-sectional view showing the state of a protective film forming sheet after punching according to another embodiment.

Figure 5 is a schematic perspective view of the protective film forming sheet after the punching process.

Figure 6 is a schematic perspective view showing the waste removal step.

FIG7 is a cross-sectional view showing the state of the protective film forming sheet passing through the roller after the punching process step.

FIG8 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 the present embodiment into a protective film.

FIG9 is a schematic cross-sectional view for explaining the step of attaching the protective film forming sheet of this embodiment to the wafer.

FIG10 is a schematic cross-sectional view for explaining the singulation step of a wafer with a protective film.

FIG11 is a schematic cross-sectional view for explaining the step of placing a chip with a protective film on a substrate.

First, let’s explain the main terms used in this manual.

The workpiece is a plate-like body to be processed and attached to the protective film forming film of the present embodiment. Examples of the workpiece include wafers and panels. Specifically, semiconductor wafers and semiconductor panels can be listed. 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 exemplified. At this time, the protective film is formed on the back side of the wafer and the chip.

The "surface" of a workpiece such as a wafer refers to the surface on which circuits and convex electrodes such as bumps are formed, and the "backside" refers to the surface on which circuits, electrodes (such as convex electrodes such as bumps) are not formed.

In this specification, for example, "(meth)acrylate" is used as a term to represent both "acrylate" and "methacrylate", and the same applies to other similar terms.

The peelable film is a film that supports the protective film in a peelable manner. The film is not limited in thickness and is used as a sheet.

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

Below, according to the specific implementation scheme, the present invention is described in detail in the following order.

(1. Protective film forming film)

As shown in FIG. 1 and FIG. 5 , the protective film forming sheet 10 of the present embodiment is a long sheet having a protective film forming film 11 and a first release film 12 disposed on one surface of the protective film forming film 11, and is usually rolled up into a roll.

The protective film forming film 11 is attached to the workpiece and formed into a protective film, thereby forming a protective film for protecting the workpiece or the processed product of the workpiece.

"Protecting" means making the protective film-forming film 11 into a state having sufficient properties for protecting the workpiece or the processed product of the workpiece. Specifically, when the protective film-forming film of the present embodiment is curable, "Protecting" means making the uncured protective film-forming film into a cured product. In other words, the protective film-forming film that has been protective is a cured product of the protective film-forming film, which is different from the protective film-forming film.

After the workpiece is superimposed on the curable protective film forming film, the protective film forming film is cured, thereby making it possible to firmly adhere the protective film to the workpiece and form a durable protective film.

When the protective film forming film 11 does not contain a curable component and is used in a non-cured state, when the protective film forming film of this embodiment is attached to the workpiece, the protective film forming film is converted into a protective film. In other words, the protective film may be the same as the protective film forming film.

When high protective performance is not required, the protective film-forming film does not need to be cured, so the protective film-forming film can be non-curable.

In the present embodiment, the protective film-forming film is preferably curable. Therefore, the protective film is preferably a cured product. Examples of cured products include thermosetting products and energy ray cured products. In the present embodiment, the protective film is more preferably a thermosetting product.

In addition, the protective film forming film preferably has adhesiveness at room temperature (23°C) or preferably exhibits adhesiveness by heating. Thus, the workpiece and the protective film forming film can be attached to each other when they are superimposed. Therefore, positioning can be performed reliably before the protective film forming film is cured.

The protective film forming film may be composed of one layer (single layer) or multiple layers of two or more layers. When the protective film forming film has multiple layers, these multiple layers may be the same as each other or different from each other, and the combination of layers constituting these multiple layers is not particularly limited.

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 interlayer peeling due to the difference in thermal expansion between the layers in the step where the temperature changes (during the reflow treatment or when the device is used). If it is a single layer, this risk can be reduced.

The thickness of the protective film forming film is not particularly limited, but is preferably less than 100 μm, more preferably less than 70 μm, further preferably less than 45 μm, and particularly preferably less than 30 μm. If the thickness of the protective film forming film is within the above range, even if the protective film forming film after the punching process contacts and adheres to the useless part when passing through the roller after the punching process, it is easy to separate again after passing through the roller. In addition, the thickness of the protective film forming film is preferably more than 5 μm, more preferably more than 10 μm, and further preferably more than 15 μm. If the thickness of the protective film forming film is within the above range, the protective performance of the obtained protective film becomes good.

In addition, the thickness of the protective film forming film refers to the thickness of the protective film forming film as a whole. 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.

The following describes the protective film formed on a wafer as a workpiece. Specifically, the protective film formed by converting the protective film forming film of the present embodiment into a protective film using the wafer 30 with a protective film shown in FIG. 8 is described.

As shown in FIG8 , the chip 30 with a protective film has a protective film 32 formed on the back side of the chip 31 (the upper side in FIG8 ), and a convex electrode 33 formed on the surface side of the chip 31 (the lower side in FIG8 ).

A circuit is formed on the surface side of the chip 31, and a convex electrode 33 is formed on the surface side in a manner electrically connected to the circuit. The chip 30 with a protective film is arranged in a manner such that the surface on which the convex electrode 33 is formed faces the chip mounting substrate. Then, by a predetermined heat treatment (reflow treatment), the convex electrode 33 is electrically and mechanically connected to the substrate, thereby being mounted. Examples of the convex electrode 33 include a bump, a pillar electrode, and the like.

(1.1 Adhesion between protective film forming films)

In the present embodiment, the adhesion of the protective film-forming films constituting the protective film-forming sheet when attached to each other is controlled within a specified range, thereby suppressing the defective removal of waste materials. Specifically, the present embodiment is characterized in that the adhesion after attaching two protective film-forming films at 23°C with a load of 2kgf for 2 minutes is 19N/25mm or less. The adhesion is preferably 15N/25mm or less, and more preferably 11N/25mm or less. In addition, if the adhesion is too small, the holding performance of the workpiece may sometimes decrease, so the adhesion is preferably 0.1N/25mm or more, more preferably 1N/25mm or more, and particularly preferably 3N/25mm or more. In addition, the reason for measuring the adhesion force after the protective film forming films are attached to each other for 2 minutes is that in the device for removing waste materials and attaching to the workpiece, in the step of the protective film forming sheet passing through the roller 19, the time for the cut part to contact the roller 19 and stop is about 2 minutes.

As described above, by controlling the adhesion between the protective film forming films within a specified range, even if the protective film forming sheet is bent after the punching process, the protective film forming film 16 and the useless portion 17 after the punching process are attached, and the protective film forming film 16 and the useless portion 17 can be separated again after the protective film forming sheet passes through the roller, which can reduce the defect of waste material removal.

(1.2 Composition for forming protective film)

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 (composition for protective film forming film) 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 condensation reaction.

In addition, the components contained in the polymer component are sometimes also curable components. In this embodiment, when the protective film forming film composition contains such a component that is both a polymer component and a curable component, the protective film forming film composition is regarded as containing a polymer component and a curable component.

(1.2.1 Polymer composition)

The polymer component (A) makes the protective film-forming film film-forming (film-forming) and gives it appropriate viscosity so that the protective film-forming film is reliably 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, the adhesion between the protective film-forming films tends to increase. On the other hand, if the weight average molecular weight is too high, the miscibility with other components deteriorates, resulting 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 preferred.

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-speed GPC device "HLC-8120GPC" manufactured by TOSOH CORPORATION is used, in which high-speed columns "TSK gurd column H _XL -H", "TSK Gel GMH _XL ", and "TSK Gel G2000 H _XL " (all manufactured by TOSOH CORPORATION) are connected in sequence, and the measurement is performed under the conditions of a column temperature of 40°C and a liquid feeding rate of 1.0 mL/min, using a differential refractometer as a detector.

As an acrylic resin, for example, a (meth)acrylate copolymer composed of a (meth)acrylate monomer and a structural unit derived from a (meth)acrylate derivative can be listed. Among them, as a (meth)acrylate monomer, a (meth)acrylate alkyl ester having an alkyl group with 1 to 18 carbon atoms can be preferably listed, and specifically, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, etc. can be listed. In addition, as a (meth)acrylate derivative, for example, (meth)acrylic acid, glycidyl (meth)acrylate, hydroxyethyl (meth)acrylate, etc. can be listed.

In this embodiment, glycidyl methacrylate or the like is preferably used to introduce glycidyl groups into the acrylic resin. The acrylic resin into which the glycidyl groups are introduced has higher solubility with the epoxy resin described later as a thermosetting component, and the glass transition temperature (Tg) of the protective film-forming film after curing becomes higher, and the heat resistance increases. In addition, in this embodiment, in order to control the adhesion or adhesiveness to the workpiece, hydroxyethyl acrylate or the like is preferably used to introduce hydroxyl groups into the acrylic resin.

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, 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 to the above range, the fluidity of the protective film formation film and the protective film during heating can be suppressed, so that a smooth protective film can be easily obtained. If the glass transition temperature is too low, there is a tendency for the adhesion between the protective film formation films to increase. If the glass transition temperature is too high, the miscibility with other components deteriorates, which will hinder the formation of a uniform film.

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

In the formula, Tg is the glass transition temperature of the acrylic resin, m is an integer greater than 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.

In the formula, m and Wk are the same as the above m and Wk.

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

When the total weight of the protective film forming film composition is set to 100 parts by mass, the content of the polymer component is preferably 5 to 80 parts by mass, more preferably 8 to 70 parts by mass, more preferably 10 to 60 parts by mass, more preferably 12 to 55 parts by mass, further preferably 14 to 50 parts by mass, and particularly preferably 15 to 45 parts by mass. By making the content of the polymer component within the above range, the amount of low molecular weight components that increase the adhesion between the protective film forming films can be limited to an appropriate range, thereby making the material design of the protective film forming film composition easy.

(1.2.2 Thermosetting components)

The curable component (B) cures the protective film-forming film to form a hard protective film. As the curable component, a thermosetting component, an energy ray curable component, or a mixture thereof can be used. When curing by irradiating energy rays, the protective film-forming film of the present embodiment contains fillers and coloring agents described later, and the light transmittance decreases. Therefore, for example, when the thickness of the protective film-forming film becomes thicker, the energy ray curing tends to become insufficient.

On the other hand, even if the thickness of the thermosetting protective film forming film increases, it can be fully cured by heating, so a protective film with high protective performance can be formed. In addition, by using conventional heating equipment such as a heating oven, multiple protective film forming films can be heated at one time to thermally cure them.

Therefore, in this embodiment, the curable component is preferably thermosetting. That is, the protective film forming film of this embodiment is preferably thermosetting.

Whether the protective film forming film is thermosetting can be determined in the following manner. First, the protective film forming film at room temperature (23°C) is heated to a temperature higher than room temperature, and then cooled to room temperature, thereby forming a heated and cooled protective film forming film. Then, 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. When the heated and cooled protective film forming film is harder, it is determined that the protective film forming film is thermosetting.

As the thermosetting component, for example, epoxy resin, thermosetting polyimide resin, unsaturated polyester resin and a mixture of these resins are preferably used. In addition, thermosetting polyimide resin refers to a general term for low molecular weight, low viscosity monomers or precursor polymers that form polyimide resins by thermal curing. Non-limiting specific examples of thermosetting polyimide resins are described in, for example, the Journal of the Fiber Society "Fibers and Industry", Vol. 50, No. 3 (1994), P106-P118.

Epoxy resin as a thermosetting component has the property of being three-dimensionally networked when heated and forming a strong coating. As such epoxy resin, various known epoxy resins can be used. In the present 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 further preferably 150 to 1,000 g/eq.

As such epoxy resins, specifically, there can be cited glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenol novolak, cresol novolak, etc.; glycidyl ethers of alcohols such as butanediol, polyethylene glycol, polypropylene glycol, etc.; glycidyl ethers of carboxylic acids such as phthalic acid, isophthalic acid, tetrahydrophthalic acid, etc.; glycidyl ethers of aniline isocyanurate substituted with a glycidyl group; Glycidyl or alkylglycidyl epoxy resins formed by active hydrogen bonded to nitrogen atoms such as isocyanurate; so-called alicyclic epoxy resins having epoxy groups introduced by, for example, oxidizing the carbon-carbon double bond in the molecule, such as vinylcyclohexanediepoxide, 3,4-epoxycyclohexylmethyl-3,4-dicyclohexanecarboxylate, 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, etc. In addition, epoxy resins having biphenyl skeletons, dicyclohexadiene skeletons, naphthalene skeletons, etc. can also be used.

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. There are several methods for activating heat-activated latent epoxy resin curing agents: a method of generating active species (anions and cations) in a chemical reaction based on heating; a method of stably dispersing in epoxy resin at room temperature, but being miscible with epoxy resin at high temperature, dissolving and initiating a curing reaction; a method of using a molecular sieve encapsulated curing agent to dissolve at high temperature and initiate a curing reaction; and a method based on microcapsules.

Among the methods exemplified, a method that stably disperses in epoxy resin at around room temperature but miscibles with epoxy resin at high temperature, dissolves and initiates a curing reaction is preferred.

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

In addition, phenolic resin is also preferred as a curing agent for epoxy resin. As phenolic resin, condensates of phenols such as alkylphenol, polyphenol, naphthol 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, polyvinyl phenolic resin, bisphenol A novolac resin, or modified products thereof can be used.

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

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, 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) to the above range, the network structure of the protective film becomes dense, and it is easy to obtain the performance of the protective film and the workpiece protection.

When dicyandiamide is used as a curing agent (C), it is preferred to use a curing accelerator (D) at the same time. As a curing accelerator, for example, 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 are preferred. Among them, 2-phenyl-4-methyl-5-hydroxymethylimidazole is particularly preferred.

The content of the curing accelerator is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, 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) to the above range, the network structure of the protective film becomes dense, so it is easy to obtain the performance of the protective film and the workpiece protection.

When the total weight of the protective film-forming film composition is set to 100 parts by mass, the total content of the thermosetting component and the curing agent is preferably 3 to 80 parts by mass, further preferably 5 to 60 parts by mass, more preferably 7 to 50 parts by mass, further preferably 9 to 40 parts by mass, and particularly preferably 10 to 30 parts by mass. If the thermosetting component and the curing agent are mixed in the above ratio, it can show appropriate viscosity before curing and can be attached stably. In addition, after curing, it is easy to obtain the performance of protecting the workpiece as a protective film.

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 adhesion between the protective film forming films may increase. Therefore, it is preferred to select the type of thermosetting components and curing agents and their blending amount within the above range in a manner that controls the viscosity to an appropriate value.

(1.2.3 Energy ray curing components)

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.

The energy ray-curable component is a component that is cured by irradiating energy rays and is used to impart film-forming properties, flexibility, etc. to the protective film.

As the energy-ray-curable component, for example, a compound having an energy-ray-curable group is preferably used. As such a compound, well-known energy-ray-curable components can be listed.

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 adhesion between the protective film forming films may increase. Therefore, it is preferable to select the type of energy ray curable component and its blending amount in a way that the viscosity is controlled to an appropriate value.

(1.2.4 Filling materials)

By making the protective film forming film contain a filler (E), it becomes easy to adjust the thermal expansion coefficient of the protective film obtained by making the protective film forming film into a protective film, and by making the thermal expansion coefficient close to the thermal expansion coefficient of the workpiece, the bonding reliability of the package obtained using the protective film forming film is further improved. In addition, by making the protective film forming film contain a filler (E), a hard protective film can be obtained, and the moisture absorption rate of the protective film is further reduced, and the bonding reliability of the package is further improved.

The filler (E) may be any of an organic filler and an inorganic filler, but is preferably an inorganic filler from the perspective of shape stability at high temperatures.

Preferred inorganic fillers include, for example, powders such as silica, alumina, talc, calcium carbonate, red iron oxide, silicon carbide, and boron nitride; beads obtained by spheronizing these inorganic fillers; surface modified products of these inorganic fillers; single crystal fibers of these inorganic fillers; glass fibers, etc. Among them, silica and surface-modified silica are preferred. As surface-modified silica, it is preferred to use a coupling agent for surface modification, and it is more preferred to use a silane coupling agent for surface modification.

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

By setting the average particle size of the filler to the above value, the operability of the protective film-forming composition becomes good. Therefore, the quality of the protective film-forming composition and the protective film-forming film is easy to stabilize.

In addition, unless otherwise specified, the "average particle size" in this manual refers to the particle size (D50) at the 50% cumulative value in the particle size distribution curve obtained by the laser diffraction scattering method.

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

By setting the content of the filler to the above value, it is easy to control the adhesion between the protective film forming films within an appropriate range. If the content of the filler is too small, the viscosity of the protective film forming film increases, and the adhesion between the protective film forming films increases excessively. On the other hand, if the amount of the filler is too much, the conformability of the protective film forming film may decrease, and the film may not be able to maintain its shape due to bending on the roll, and the viscosity of the protective film forming film and the adhesion to the workpiece may decrease excessively.

In addition, 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 contain two or more fillers of different materials, and may contain two or more fillers with different average particle sizes.

In this embodiment, it is preferred to contain two or more fillers with different average particle sizes. By making the protective film forming film contain fillers with different average particle sizes, it is easy to arrange fillers with smaller average particle sizes in the gaps of fillers with larger average particle sizes. As a result, the above-mentioned effects can be obtained, and it is easy to set the adhesion between the protective film forming films within the above-mentioned range.

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

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

(1.2.5 Coupling agent)

The protective film forming film preferably contains a coupling agent (F). By containing a coupling agent, the heat resistance of the protective film can be improved after the protective film forming film is cured without damaging the heat resistance of the protective film, and the adhesion between the protective film and the workpiece can be improved. At the same time, the water resistance (wet and heat resistance) can be improved. As a coupling agent, silane coupling agents are preferred from the perspective of its versatility and cost advantage.

As the silane coupling agent, for example, γ-glycidyloxypropyl trimethoxysilane, γ-glycidyloxypropyl methyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, γ-(methacryloxypropyl)trimethoxysilane, γ-aminopropyl trimethoxysilane, N-6-(aminoethyl)-γ-aminopropyl trimethoxysilane, N-6-(aminoethyl)- )-γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-butylpropyltrimethoxysilane, γ-butylpropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfide, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane, etc. These silane coupling agents can be used alone or in combination of two or more.

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

(1.2.6 Colorants)

The protective film forming film preferably contains a colorant (G). As a result, since the back of the processed product such as a chip is covered, various electromagnetic waves generated in the electronic device can be blocked, and the failure of the processed product such as the chip can be reduced. In addition, when a defect in waste removal occurs, it can be immediately discovered with the naked eye.

As the coloring agent (G), for example, known coloring agents such as inorganic pigments, organic pigments, and organic dyes can be used. In the present embodiment, inorganic pigments are preferred.

Examples of inorganic pigments include carbon black, cobalt pigments, iron pigments, chromium pigments, titanium pigments, vanadium pigments, zirconium pigments, molybdenum pigments, ruthenium pigments, platinum pigments, ITO (indium tin oxide) pigments, and ATO (antimony tin oxide) pigments. Among them, carbon black is particularly preferred. Carbon black can block electromagnetic waves in a wider wavelength range.

The amount of colorant (especially carbon black) blended in the protective film-forming film varies depending on the thickness of the protective film-forming film. For example, when the thickness of the protective film-forming film is 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.

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. If the average particle size of the colorant is within the above range, it is easy to control the transmittance within the desired range.

(1.2.7 Other additives)

The protective film-forming film composition may contain, as other additives, photopolymerization initiators, crosslinking agents, plasticizers, antistatic agents, antioxidants, impurity absorbers, thickeners, and stripping agents, etc., within the scope of not impairing the effects of the present invention.

Among them, it is preferred that the content of the stripping agent in the protective film forming film composition is less than the prescribed amount. In the present embodiment, it is preferably less than 0.00099% by mass relative to the total mass of the protective film forming film. If the content of the stripping agent is too much, the adhesion reliability between the protective film and the workpiece tends to decrease. Examples of the stripping agent include alkyd stripping agents, silicone stripping agents, fluorine stripping agents, unsaturated polyester stripping agents, polyolefin stripping agents, and wax stripping agents.

(1.2.8 Control of adhesion between protective film forming films)

As described above, the feature of the present embodiment is that the adhesion between the protective film forming films constituting the protective film forming sheet when attached to each other is controlled within a specified range, thereby suppressing the defective removal of waste materials.

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

If the weight average molecular weight of the polymer component (A) is low, the adhesion tends to increase. If the glass transition temperature of the polymer component (A) is low, the adhesion tends to increase. In addition, if a low molecular weight compound is used as a curable component (B), a curing agent (C), a curing accelerator (D), or an energy ray curable component, the adhesion tends to increase. If the blending amount of the filler (E) is large, the adhesion tends to decrease.

Adhesion can also be controlled by partially curing the protective film forming film. For example, by partially curing the curable component (B), adhesion can be reduced. The timing of partially curing the protective film forming film is not particularly limited, for example, as long as it is the stage before the protective film forming sheet passes through the roller 19 when punching. However, from the perspective of setting the peeling forces F1 and F2 described later within an appropriate range and the perspective of adhesion to the workpiece, the protective film forming film is preferably not partially cured as described in the embodiment described later.

(2. Sheet for forming protective film)

Before use, the protective film forming film can be rolled up and stored in the form of a double-layered protective film forming sheet 10 in which a peelable protective film forming film 11 is stacked on a first peeling film 12 as shown in FIG1. In addition, it can also be rolled up and stored in the form of a three-layered protective film forming sheet 20 in which the protective film forming film 11 is sandwiched between two peeling films (a first peeling film 12 and a second peeling film 13) as shown in FIG3 (another embodiment). The peeling film is peeled off when the protective film forming film is used.

The protective film forming sheet is long and is rolled into a roll for storage and transportation. As such a protective film forming sheet, there is also known a protective film forming sheet in which the 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 of the punched protective film forming sheet is stacked on the first release film 12 (Figure 2), or sandwiched between two release films (12, 13) (Figure 4).

The first peeling film can be composed of one layer (single layer) or two or more layers of substrate. From the perspective of controlling the peeling property, the surface of the substrate can be subjected to a peeling treatment. That is, the surface of the substrate can be modified, and a material that is not from the substrate can also be formed on the surface of the substrate. In this embodiment, it is preferred that the first peeling film has a substrate and a peeling agent layer. By having a peeling agent layer, it is easy to control the physical properties of the surface of the first peeling film on which the peeling agent layer is formed. In this embodiment, after a coating agent containing a peeling agent layer composition described later is applied on one surface of the substrate, the coating film is dried and cured to form a peeling agent layer. Thus, the first peeling film can be obtained.

The thickness of the first peeling 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.

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, before being transported to the next step, the protective film forming sheet 10 passes through the guide rollers and other rollers in the device, but 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 being peeled off from the first release film 12.

In addition, the thickness of the first peeling film 12 refers to the thickness of the first peeling film as a whole. For example, the thickness of the first peeling film composed of multiple layers refers to the total thickness of all layers constituting the first peeling film.

As the base material of the first release film 12, resin films and paper can be listed. As the resin of the resin film, polyethylene terephthalate, polyethylene, polypropylene, polybutylene, polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polybutylene terephthalate, polyurethane, ethylene-vinyl acetate copolymer, polymer resin, ethylene (meth) acrylic acid copolymer, polystyrene, polycarbonate, fluororesin, low-density polyethylene, linear low-density polyethylene and triacetyl cellulose can be listed. As the paper, high-quality paper, coating paper (coat paper), glass paper and laminated paper can be listed. These base materials can be used alone or in combination of two or more. Among them, polyethylene terephthalate film is preferred because it is cheap and has high rigidity.

At least one surface of the first peeling film 12 (the surface overlapping the protective film forming film layer) can be peeled by a peeling agent layer composition. The thickness of the peeling agent layer is preferably greater than 30nm and less than 200nm, and more preferably greater than 50nm and less than 180nm.

The surface elastic modulus (23°C) of the surface of the first peeling film 12 in contact with the protective film forming film 11 is preferably 17 MPa or less, further preferably 14 MPa or less, more preferably 13 MPa or less, and particularly preferably 12 MPa or less. The surface elastic modulus is an indicator of the ease of deformation of the surface. By setting the surface elastic modulus of the surface of the first peeling film 12 in contact with the protective film forming film 11 within the above range, it is possible to suppress the occurrence of floating (peeling of about 1 to 4 mm) between the protective film forming film 11 and the first peeling film 12 when the punch is pressed and then pulled up in the punching process. This is believed to be because the surface of the first peeling film 12 is relatively soft, and even if there is compression based on the punch and decompression based on its decompression, the surface of the first peeling film will follow the deformation of the protective film forming film. By suppressing the occurrence of floating, the defective removal of waste materials can be further reduced. The lower limit of the surface elastic modulus 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 increase, so it is preferably 3MPa or more, more preferably 4MPa or more, and particularly preferably 5MPa or more.

The surface elastic modulus of the first peeling film 12 at 23°C on the surface in contact with the protective film forming film 11 can be measured using an atomic force microscope equipped with a cantilever. That is, the surface of the first peeling film 12 in contact with the protective film forming film 11 is pressed and pulled by the cantilever to obtain a force curve. The obtained force curve is fitted based on the JKR theoretical formula to obtain the elastic modulus, which is used as the surface elastic modulus of the present invention. The specific measurement method will be described in detail in the embodiments described below.

In order to set the peeling force F1 described later within an appropriate range and set the surface elastic modulus of the first peeling film 12 within the above range, in this embodiment, the composition used as the peeling agent layer is preferably an alkyd release agent, a silicone release agent, a fluorine release agent, an unsaturated polyester release agent, a polyolefin release agent, or a wax release agent, among which a silicone release agent is preferred, and a silicone release agent and a heavy peeling additive are particularly preferred.

As a silicone-based mold release agent, a silicone mold release agent mixed with silicone having dimethyl polysiloxane as a basic skeleton can be used.

The silicone can be any one of the addition reaction type, condensation reaction type, and energy ray curing type such as ultraviolet curing type and electron beam curing type, but addition reaction type silicone is preferred. Addition reaction type silicone has high reactivity and excellent productivity, and compared with condensation reaction type, it has the advantages of small change in peeling force after manufacturing and no curing shrinkage.

As specific examples of addition-reaction-type siloxanes, there can be cited organic polysiloxanes having two or more alkenyl groups with 2 to 10 carbon atoms, such as vinyl, allyl, propenyl, and hexenyl, at the ends and/or side chains of the molecules. From the perspective of reducing the surface elastic modulus, it is preferred that the number of alkenyl groups in the addition-reaction-type siloxanes is small.

When the total weight of the stripping agent layer composition (excluding the catalyst described below) is set to 100 parts by mass, the content of siloxane composed of dimethyl polysiloxane is preferably less than 100 parts by mass, further preferably less than 90 parts by mass, more preferably less than 80 parts by mass, and particularly preferably less than 70 parts by mass.

When using this addition reaction type silane, it is preferred to use a crosslinking agent and a catalyst at the same time.

As a crosslinking agent, for example, an organic polysiloxane having at least two silicon atoms bonded to hydrogen atoms in one molecule can be cited. From the perspective of reducing the surface elastic modulus, it is preferred that the crosslinking agent content in the stripping agent layer composition is small.

As specific examples of crosslinking agents, there can be cited dimethylhydrosiloxane-methylhydrosiloxane copolymers end-capped with dimethylhydrosiloxane, trimethylhydrosiloxane-methylhydrosiloxane copolymers end-capped with dimethylhydrosiloxane, trimethylhydrosiloxane-methylhydropolysiloxane, poly(hydrosilsesquioxane), etc.

As catalysts, there are microparticles of platinum, microparticles of platinum adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin compounds of chloroplatinic acid, and platinum group metal compounds such as palladium and rhodium.

By using this catalyst, the curing reaction of the stripper layer composition can be carried out more effectively.

From the perspective of setting the surface elastic modulus within the above range and setting the peeling force F1 described later within an appropriate range, when the total weight of the stripping 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.

The heavy-stripping additive is used to increase the stripping force F1 described later. Examples of heavy-stripping additives include silicone resins, silane coupling agents and other organic silanes, among which silicone resins are preferred.

As the silicone resin, for example, MQ resin is preferably used, which contains an M unit as a monofunctional siloxane unit [R ₃ SiO _1/2 ] and a Q unit as a tetrafunctional siloxane unit [SiO _4/2 ]. In addition, 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 siloxane migration, one or more of the three Rs in the M unit are preferably a hydroxyl group or a vinyl group, and more preferably a vinyl group. From the perspective of reducing the surface elastic modulus, the content of the silicone resin (especially the MQ resin) in the stripping agent composition is preferably small.

When the total weight of the stripping agent layer composition (excluding the catalyst) is set to 100 parts by mass, the content of the heavy stripping additive is preferably 0 to 50 parts by mass, further preferably 5 to 45 parts by mass, and particularly preferably 10 to 40 parts by mass.

From the perspective of adjusting the viscosity and improving the coating properties on the substrate, the composition for the stripping agent layer is preferably used as a coating agent containing a diluent solvent in addition to the above-mentioned various active ingredients. In this specification, "active ingredient" refers to the ingredients contained in the coating agent containing the composition as an object, excluding the diluent solvent.

As diluent solvents, there are 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 diluent solvents may be used alone or in combination of two or more.

The concentration of the active ingredient (solid content) of the coating agent containing the peeling agent composition is preferably 0.3 to 10% by mass, more preferably 0.5 to 5% by mass, and further preferably 0.5 to 3% by mass.

The composition for the stripping agent layer may contain additives commonly used in stripping agent layers within the range that does not impair the effect of the present invention. Examples of such additives include dyes and dispersants.

In the protective film forming sheet 10 of the present embodiment, the protective film forming film 11 is preferably punched into a predetermined shape. That is, the cutout 14 is preferably formed on the protective film forming sheet in such a manner that a portion of the protective film forming sheet 10 has a predetermined closed shape when the protective film forming sheet 10 is viewed from above. In addition, from the perspective that the protective film forming film does not overflow from the workpiece when the protective film forming film is attached to the workpiece, the shape of the protective film forming film after punching is preferably smaller than the shape of the workpiece.

(3. Method for manufacturing a protective film forming sheet)

The method for producing the protective film-forming film is not particularly limited. The film can be produced using a coating agent containing the above-mentioned 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.

The obtained coating agent is applied to the release surface of the first release film 12 using a coating machine such as a roll coater, a doctor blade coater, a roll knife coater, an air knife coater, a die coater, a rod coater, a gravure coater, a curtain coater, and the like, and then dried to obtain the protective film-forming sheet 10 of the present embodiment having the protective film-forming film 11 on the first release film 12. Alternatively, the coating agent may be applied to another resin film and dried to transfer the obtained protective film-forming film to the first release film. When obtaining a protective film forming sheet 20 of another embodiment, a second release film 13 is bonded to the exposed surface of the protective film forming film 11 stacked with the first release film 12, thereby obtaining a protective film forming sheet 20 in which the protective film forming film 11 is sandwiched between two release films.

(4. Method for manufacturing a punched protective film forming sheet)

A method for punching the protective film forming sheet 10 and obtaining a protective film forming film 16 punched into a predetermined closed shape on the first release film 12 is described.

(4.1 Punching process steps)

First, prepare the protective film forming sheet 10 shown in FIG. 1 which has not been punched. Use a punch (not shown) to cut a cut 14 from the protective film forming film 11 side of the protective film forming sheet 10 in a manner that penetrates the protective film forming film 11 and reaches a portion of the surface of the first peeling film 12. The operation of cutting a cut in a manner that reaches a portion of the surface without completely cutting is called a half-cut. As a result, a cut 14 is formed on a portion of the surface of the protective film forming sheet 10 in a manner having a prescribed closed shape (see FIG. 2 and FIG. 5). Here, when the protective film forming film is transferred to a semiconductor wafer, the prescribed closed shape is a shape substantially the same as that of the wafer. That is, the cutout 14 is formed in a shape roughly 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 step is called a "punching process step".

By the punching process, the protective film forming film 11 is divided into a protective film forming film 16 punched into a predetermined closed shape and a continuous useless portion 17 around it. In the long side direction of the protective film forming sheet 10, the protective film forming film 16 punched into a predetermined closed shape is provided at multiple locations.

In the punching process step, a known punching die can be appropriately used. The punching process is performed by half-cutting in a manner that completely cuts the protective film forming film 11 and does not completely cut the first peeling film 12.

As shown in FIG. 2 and FIG. 4 , the cross-sectional shape of the cut 14 is generally wedge-shaped, and the width of the cut 14 is wider on the upper surface side of the protective film forming film 11 where the punch enters, and narrows on the lower surface side (the interface between the protective film forming film 11 and the first peeling film 12). The width of the cut 14 is not particularly limited, but from the perspective of preventing the contact and adhesion between the punched protective film forming film 16 and the useless portion 17, or from the perspective of shortening the contact and adhesion time, the width D of the cut 14 on the lower surface of the protective film forming film 11 (i.e., the upper surface of the first peeling film 12) is preferably 8 μm or more, more preferably 10 μm or more, further preferably 15 μm or more, and particularly preferably 20 μm or more. As the width D, the protective film forming sheet can be cut in the thickness direction, and the width of the cut on the upper surface of the first peeling film 12 of the cross section can be measured as the width D. The upper limit of the width D is not particularly limited, but considering the width of the cutter that can reliably cut the protective film forming film, it is usually 100 μm or less, preferably 80 μm or less, more preferably 60 μm or less, and further preferably 40 μm or less. In order to form such a cut 14, it is preferred to use a cutter with a wider blade width at the front end as a punch.

After the above steps, a punched protective film forming sheet 10 can be obtained. On the protective film forming sheet, a cut 14 is formed in such a way that a portion of the protective film forming sheet has a predetermined closed shape (for example, a shape roughly the same as the plane shape of the semiconductor wafer) when the punched protective film forming sheet 10 is viewed from the upper surface of the protective film forming film 11, and the cut 14 reaches a portion of the first release film 12 in the thickness direction of the protective film forming sheet 10. That is, a cut is also formed on the surface of the first release film 12 that is in contact with the protective film forming film 11. By making the dicing knife reach the first release film 12, the protective film forming film 11 can be completely cut.

(4.2 Waste removal steps)

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

As shown in FIG6 , in the waste removal step, the continuous useless portion 17 is peeled off from the first peeling film 12, so that the protective film forming film 16 that has been punched remains on the first peeling film 12. The peeled useless portion 17 is wound on the waste roller.

According to the protective film forming sheet 10 of the present embodiment, since the adhesion between the protective film forming films is low, even if the punched protective film forming film 16 and the useless portion 17 come into contact and adhere when passing through the roller 19 after the punching process, the protective film forming film 16 and the useless portion 17 can be separated again after passing through the roller. As a result, the defective waste removal in the waste removal step can be suppressed.

The protective film forming sheet 10 that has been punched can be rolled into a roll for storage and transportation.

(5. Processing method of workpiece)

As an example of a method for processing a workpiece using a punched protective film forming sheet according to the present embodiment, a method for manufacturing a package of a chip with a protective film obtained by processing a wafer with a protective film formed thereon on a substrate is described.

The manufacturing method of the device of this embodiment has at least the following steps 1 to 9.

Step 1: Punching the protective film forming sheet 10

Step 2: The punched protective film forming sheet passes between rollers

Step 3: Step of removing the useless portion 17 of the protective film forming sheet 10

Step 4: A step of attaching the protective film forming film 11 of the protective film forming sheet 10 to the back of the wafer

Step 5: The step of forming the attached protective film into a protective film

Step 6: Step of peeling off the first peeling film from the protective film or protective film forming film

Step 7: Singulate the wafer having a protective film or a protective film-forming film on the back to obtain a plurality of wafers with protective films or protective film-forming films

Step 8: The step of placing the chip with the protective film or the protective film forming film on the substrate

Step 9: A step of heating the chip with a protective film or a protective film-forming film disposed on the substrate and the substrate

Step 1 to step 3 are as described above. Step 5 can be performed before step 6, or after any step from step 6 to step 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.

Referring to the drawings, the manufacturing method of the device having the above steps 1 to 9 is described.

Figures 2, 4, and 5 show the outline of step 1 as described above. Figure 6 shows the outline of step 3.

As shown in FIG. 9 , a protective film forming film 11 of a protective film forming sheet 10 is attached to the back of a wafer 21 (step 4). Then, the attached protective film forming film 11 is protected to form a protective film 32 (step 5), and a wafer with a protective film is obtained. When the protective film forming film 11 is thermosetting, the protective film forming film 11 can be heated at a specified temperature for an appropriate time. In addition, when the protective film forming film 11 is energy ray curable, an energy ray transmitting film can be used as the first peeling film 12 and the energy ray can be incident from the side of the first peeling film 12.

In addition, the protective film forming film 11 can be cured after the dicing step described later, or the protective film forming film 11 can be cured after the wafer with the protective film forming film is picked up from the dicing sheet.

Then, the wafer 21 with the protective film is transferred to a known cutting sheet 22, and the wafer 21 with the protective film is cut, as shown in FIG10, to obtain a chip 31 with a protective film 32 (chip 30 with a protective film) (step 7). Then, the cutting sheet 22 is expanded along the plane direction as needed, and the chip 30 with the protective film is picked up from the cutting sheet 22 using a suction nozzle (not shown).

The picked-up chip 30 with protective film can be transported to the next step, or it can be temporarily stored on a tray, tape, etc. and transported to the next step after a specified period of time.

As shown in FIG. 11 , the chip 30 with a protective film transported to the next step is transported to the substrate 50 by the suction nozzle, and the terminal portion on the substrate is detached from the suction nozzle and arranged at a position where the convex electrode 33 such as a bump can be connected to the terminal portion such as a pad (step 8). At this time, other chips different from the chip 30 with a protective film can also be mounted on the substrate 50. Therefore, multiple chips can be mounted on the substrate.

The chip with the protective film arranged at a predetermined position on the substrate is subjected to a heat treatment (reflow treatment) (step 9). As the reflow treatment conditions, for example, the preferred maximum heating temperature is 180-350°C and the reflow time is 2-10 minutes.

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

(6. Variations)

In the above, the embodiment of the present invention is described by taking as an example a protective film forming sheet having a double-layer structure with a protective film forming film 11 on a first peeling film 12, but a second peeling film 13 may be stacked on the exposed surface of the protective film forming film 11. That is, the protective film forming sheet may also be a protective film forming sheet 20 in which the protective film forming film 11 is sandwiched between the first peeling film 12 and the second peeling film 13 (see FIG. 3 and FIG. 4). In this case, the second peeling film 13 may be peeled off before the protective film forming film 11 is attached to the workpiece.

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

In addition, in the present embodiment, in the protective film forming sheet 20, when the peeling force when peeling the first peeling film 12 from the protective film forming film 11 is set to F1, and when the peeling force when peeling the second peeling film 13 from the protective film forming film 11 is set to F2, F1 and F2 preferably satisfy the relationship of F1>F2. By satisfying this relationship, when removing the second peeling film 13 from the protective film forming sheet 20, the protective film forming film 16 that should be left will not be removed together with the second peeling film 13, and the protective film forming film 16 is easy to remain on the first peeling film 12, which can further suppress the defect of waste material removal.

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

In addition, the peeling force F1 is preferably 50mN/100mm or more, further preferably 70mN/100mm or more, more preferably 90mN/100mm or more, more preferably 110mN/100mm or more, and particularly preferably 130mN/100mm or more. By making F1 within the above range, the protective film forming film 11 and the first peeling film 12 can be suppressed from being accidentally peeled off.

The adjustment of the peeling force can be controlled, for example, by the type of the peeling agent layer composition, the thickness of the peeling agent layer, etc. The second peeling film 13 is designed to have a peeling force less than that of the first peeling film 12. When the second peeling film 13 has a peeling agent layer, there is no particular limitation as long as the peeling agent layer is made of a material that can impart peeling properties. For example, the peeling agent layer of the second peeling film 13 can be the same as the peeling agent layer of the first peeling film 12, and can be obtained by curing the peeling agent layer composition containing silicon oxide.

As long as the composition for the peeling agent layer of the second peeling film 13 satisfies the above-mentioned relationship between F1 and F2, it can be selected from the materials exemplified in the first peeling film 12. Among them, for the materials exemplified as heavy peeling additives, it is preferred that the content is less than that in the first peeling film 12, or it is not included.

The thickness of the second peeling film 13 is not particularly limited, but is preferably 10 μm or more and 75 μm or less. In addition, the thickness of the second peeling film is more preferably 18 μm or more, and further preferably 24 μm or more. In addition, the thickness of the second peeling film is more preferably 60 μm or less, and further preferably 45 μm or less. From the perspective of setting the peeling force F2 and the peeling force F1 to the above-mentioned F1>F2, the thickness of the second peeling film is preferably less than the thickness of the first peeling film, and more preferably less than the thickness of the first peeling film.

In addition, the thickness of the second peeling film refers to the thickness of the second peeling film as a whole. For example, the thickness of the second peeling film composed of multiple layers refers to the total thickness of all layers constituting the second peeling film.

The manufacturing method of the protective film forming sheet 20 is as described in the embodiment, and the second release film 13 is bonded to the exposed surface of the protective film forming film 11 stacked with the first release film 12.

When punching the protective film forming sheet 20, the punching die is inserted from the side of the second release film 13 and the protective film forming film 11 and the second release film 13 are cut into a predetermined closed shape, which is the same as the above-mentioned embodiment. As a result, the punched protective film forming film 16 and the second release film 13 are obtained on the first release film 12. The punched protective film forming sheet 20 can be rolled up for storage and transportation.

In the waste material removal step, the second peeling film 13 and the useless portion 17 are wound up at the same time to remove the second peeling film 13 and the useless portion 17. At this time, the second peeling film 13 that has been completely cut by punching is rejoined by using a long adhesive tape, making it easy to remove the second peeling film 13. As a result, the protective film forming film 16 cut into a prescribed closed shape remains on the first peeling film 12.

The above is an explanation of the implementation scheme of the present invention, but the present invention is not limited to the above implementation scheme and can be modified in various forms within the scope of the present invention.

[Implementation example]

The invention is further described in detail below using examples, but the invention is not limited to these examples.

(Manufacturing of protective film forming sheet)

[First peeling film (re-peeling film)]

<Coating agent containing a peeling agent composition>

Prepare the following stripping agent composition raw materials.

．Silicone-based mold release agent containing organopolysiloxane having a vinyl group and organopolysiloxane having a hydrosilyl group (manufactured by Dow Corning Toray Co., Ltd., BY24-561, solid content 30% by mass)

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

． MQ resin with vinyl as a heavy-stripping additive (manufactured by Dow Corning Toray Co., Ltd., SD-7292, solid content 71% by mass)

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

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, and the total solid content was adjusted to 2 mass %, to prepare a coating agent containing a composition for a stripping agent layer.

<Manufacturing of the first peeling film>

A coating agent containing a peeling agent layer composition was applied on 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 coating agent was heated and dried to form a peeling agent layer on the PET film, thereby manufacturing the first peeling film (re-peeling film) A~C.

<Determination of surface elastic modulus>

The surface elastic modulus of the peeling-treated surface of the obtained first peeling film was measured in the following manner.

A cantilever made of silicon nitride material (manufactured by Bruker Corporation, trade name: MLCT, front 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 first peeling film manufactured was placed on the atomic force microscope, and the surface of the peeling agent layer of the first peeling film manufactured was pressed and pulled by the cantilever with a pressure of 2 nm and a scanning speed of 10 Hz. This operation was performed at 23°C. The force curve obtained by this operation was fitted based on the JKR theoretical formula, and the surface elastic modulus was calculated. For the surface elastic modulus, 4096 points were measured in 1μm×1μm 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.

[Second peeling film (light peeling film)]

"SP-PET 381130 (thickness 38μm)" manufactured by Lintec Corporation was used.

[Coating agent containing a protective film-forming composition]

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 was 50 mass % to prepare a coating agent.

(A) Polymer components

(A-1) (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

(A-2) (Meth)acrylate copolymer obtained 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 (weight average molecular weight: 450,000, glass transition temperature: 2°C)

(B) Curing component (thermosetting component)

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

(B-2) Bisphenol A type liquid epoxy resin dispersed with acrylic rubber particles (manufactured by Nippon Shokubai Co., Ltd., BPA328, epoxy equivalent 230g/eq, acrylic rubber content 20phr)

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

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

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

(E) Filling materials

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

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

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

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

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

The obtained protective film forming sheet was used to perform the following measurements and evaluations.

[Adhesion between protective film forming films]

The protective film-forming film is exposed from the protective film-forming sheet in the following manner, and the protective film-forming films are attached to each other to measure the adhesion.

<Fix the protective film forming film on the adhesive tape>

I. Peel off the second peeling film from the protective film forming sheet having a three-layer structure of second peeling film/protective film forming film/first peeling film.

II. At 23°C, an adhesive tape manufactured by Lintec Corporation (product name PET50PL Shin: acrylic adhesive layer/50μm PET substrate) was attached to the exposed protective film-forming film to prepare a laminated sample of "PET substrate/acrylic adhesive layer/protective film-forming film/first peeling film".

III. Cut the laminated samples into strips with a width of 25 mm and a length of 250 mm.

<Fixing the protective film forming film on the SUS plate>

I. Attach a double-sided tape with a PET film as the core material to the entire surface of a SUS plate (0.5mm thick × 70mm × 150mm).

II. Peel off the second peeling film from the protective film forming sheet having a three-layer structure of second peeling film/protective film forming film/first peeling film.

III. The exposed protective film-forming film is attached to the entire adhesive surface of the above-mentioned double-sided tape to obtain a laminated sample of "SUS plate/double-sided tape/protective film-forming film/first release film".

IV. Peel off the first peeling film to expose the protective film forming film.

<Measurement of adhesion>

The first release film was peeled off from the laminated body sample of "PET substrate/acrylic adhesive layer/protective film forming film/first release film" to expose the protective film forming film. The laminated body of "PET substrate/acrylic adhesive layer/protective film forming film" and the laminated body of "SUS plate/double-sided tape/protective film forming film" were laminated with the protective film forming films facing each other, and were bonded at 23°C using a 2kg roller.

Leave the sample to stand without heating, and measure the adhesion 2 minutes (±20 seconds) after attachment using the following measurement method.

The peeling force was measured using a universal tensile tester (manufactured by Shimadzu Corporation, product name "AUTOGRAPH AG-IS") at a measuring distance of 70 mm, a peeling speed of 300 mm/min, a temperature of 23°C, and a peeling angle of 180°. The average of the measured values between the first 10 mm and the last 10 mm of the measuring distance and 50 mm was taken as the "adhesion force between the protective film-forming films".

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

The second peeling film was peeled off from the obtained protective film forming sheet. The good adhesive surface of 25 μm thick good adhesive PET (manufactured by TOYOBO Co., Ltd., PET25A-4100) was attached to the surface of the protective film forming film exposed by peeling by hot lamination pressing (70°C, 1 m/min) to prepare a laminate sample. The laminate sample was cut into 100 mm width to prepare a measurement sample. The back of the first peeling film of the measurement sample was fixed to a hard support plate using double-sided tape.

Using a universal tensile tester (manufactured by Shimadzu Corporation, product name "AUTOGRAPH (registered trademark) AG-IS"), the protective film forming film/well-adhesive PET composite (integrated) body was peeled off from the first peeling film at a peeling angle of 180° and a peeling speed of 1m/min, and the load at this time was measured. The total measured distance was 100mm, and the average of the measured values between the first 10mm and the last 10mm removed and 80mm was taken as the peeling force F1. The results are shown in Table 2.

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

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

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

The obtained peeling forces F1 and F2 were compared, and it was confirmed that F1 was greater than F2 for all samples.

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

Using RAD-3600F/12 manufactured by Lintec Corporation with specifications for 200mm wafers, the punch was inserted from the second release film side of the protective film forming sheet to punch the protective film forming film and the second release film into a circular shape (inner diameter of 198mm). At this time, the first release film was cut in an incompletely punched manner (punching process step). Four types of punches with different blade widths of the dicing knife were used to perform half cuts with different cut widths. Punching was performed 40 times.

After the punching process, the protective film forming sheet is moved between multiple rollers. Then, the circular punched portion is left on the first release film, and the second release film and the useless portion around the circular punched portion are removed (waste removal step). At this time, the second release film that has been completely cut after the punching process is rejoined using a long adhesive tape, and the second release film is removed on this basis.

<Incision width>

The protective film forming sheet after the waste material removal step was cut in the thickness direction in a manner that the cut portion of the first release film was not deformed, and the protective film forming sheet was kept flat, and the cross section was observed using a scanning electron microscope (SEM, "VE-9800" manufactured by KEYENCE CORPORATION). The width of the cut remaining on the first release film at the interface between the first release film and the protective film forming film was measured.

Select the 20th one from the 40 circular parts, and measure it at 6 points (a regular hexagon if the points are connected) at equal intervals on the circumference of the circle. The minimum value among the 6 points is taken as the "cut width". And round off to one decimal place.

The wider the incision width, the less the protective film formation films adhere to each other, and the smoother the waste removal can be performed.

<Evaluation of waste removal performance>

In the waste removal step, the number of pieces of the protective film forming film of the circular part that float up along with the useless parts among the 40 circular parts is counted. The fewer the number of floating pieces, the more smoothly the waste removal can be performed because the protective film forming films are not attached to each other.

The above results are summarized in Table 3.

It can be confirmed from Table 3 that if the adhesion between the protective film forming films is less than 19N, the protective film forming films will not adhere to each other after the punching process, and waste removal can be performed smoothly. In addition, it can be seen that as shown in Example 7, if the incision width becomes narrower, there is a tendency that the protective film forming films will adhere to each other after the punching process and waste removal cannot be performed smoothly.

[Industrial Utilization]

As described above, according to the present invention, a protective film forming sheet and a method for manufacturing the same can be provided, which can sufficiently suppress the defect of waste material removal even when the cut width is narrow during punching.

10: Sheet for forming protective film

11: Protective film forming film

12: First peeling membrane

Claims (9)

A protective film forming sheet, which is a long sheet and has a curable protective film forming film and a first release film provided on one surface of the protective film forming film, wherein the adhesion after two protective film forming films are attached at 23°C with a load of 2kgf for 2 minutes is 19N/25mm or less. A protective film forming sheet, which is a long sheet and has a single-layer protective film forming film and a first peeling film provided on one surface of the protective film forming film, wherein, the protective film forming film is laminated on the first peeling film in a peelable manner, and the adhesion of two protective film forming films after being attached for 2 minutes at 23°C with a load of 2kgf is less than 19N/25mm. A protective film forming sheet, which is a long strip and has a first peeling film, a second peeling film, and a protective film forming film sandwiched between the first peeling film and the second peeling film, wherein the adhesion of the two protective film forming films after being attached for 2 minutes at 23°C with a load of 2kgf is less than 19N/25mm. A protective film forming sheet, which is a long sheet and has a protective film forming film containing a filler and a first release film provided on one surface of the protective film forming film, wherein the adhesion after two protective film forming films are attached at 23°C with a load of 2kgf for 2 minutes is 19N/25mm or less. The protective film forming sheet according to any one of claims 1 to 4, wherein the surface elastic modulus of the first release film in contact with the protective film forming film is 17 MPa or less. A protective film forming sheet as described in any one of claims 1 to 4, wherein, a cut is formed on the protective film forming sheet in such a manner 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 cut 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. The protective film-forming sheet according to claim 6, wherein a width of the cut at the interface between the protective film-forming film and the first release film is 8 μm or more. A method for manufacturing a punched protective film forming sheet, comprising the step of forming a cut in a manner such that a portion of the protective film forming sheet described in any one of claims 1 to 4 has a predetermined closed shape, wherein the cut 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. The method for producing a punched protective film-forming sheet according to claim 8, wherein a width of the cut at the interface between the protective film-forming film and the first release film is 8 μm or more.