JP2022032570A - Protective film forming sheet and manufacturing method thereof - Google Patents

Abstract

To provide a protective film forming sheet in which stripping defect can be sufficiently suppressed even when the cut width upon punching is relatively narrow, and a manufacturing method of the protective film forming sheet.SOLUTION: A protective film forming sheet is a long sheet including a protective film forming film and a first peeling film provided on one surface of the protective film forming film, and the adhesive force after two minutes after applying two protective film forming films at 23°C with a load of 2 kgf is 19N/25 mm or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a protective film forming sheet and a method for producing the same. In particular, a protective film forming sheet provided with a protective film forming film suitably used for protecting a work such as a semiconductor wafer or a workpiece such as a semiconductor chip obtained by processing the work, and a protective film forming sheet. Regarding the method of manufacturing a sheet.

In recent years, semiconductor devices have been manufactured by a mounting method called flip-chip bonding. In this mounting method, when a semiconductor chip having a circuit surface on which a convex electrode such as a bump is formed is mounted, the circuit surface side of the semiconductor chip is inverted (faced down) to the chip mounting portion and joined. Therefore, the structure is such that the back surface side of the semiconductor chip on which the circuit is not formed is exposed.

Therefore, in order to protect the semiconductor chip from impacts such as during transportation, a hard protective film made of an organic material is often formed on the back surface side of the semiconductor chip. An uncured resin film (hereinafter referred to as "protective film forming film") which is a precursor thereof is used for forming such a protective film. The protective film-forming film is attached to the back surface of the semiconductor wafer and diced together with the wafer to form chips. By curing the protective film forming film, a chip having a protective film on the back surface can be obtained.

As a product form of the protective film-forming film, as shown in FIG. 1, a protective film-forming sheet 10 having a two-layer structure in which the protective film-forming film 11 is releasably laminated on the first release film 12, or shown in FIG. As described above, a three-layer structure protective film forming sheet 20 in which the protective film forming film 11 is sandwiched between two release films (12, 13) is known. Further, the protective film forming sheet is long and is wound into a roll for storage and transportation. Such a protective film-forming sheet may be attached to the work by preliminarily punching the protective film-forming film into a shape substantially the same as that of the work (general term for adherends such as semiconductor wafers). In such a punched protective film forming sheet, the protective film forming film 16 punched into a predetermined closed shape is laminated on the first release film 12 (FIG. 2) or two release films. It is sandwiched between (12, 13) (Fig. 4).

The punched protective film-forming sheet is manufactured by punching the protective film-forming film into a predetermined closed shape by punching, and is used by removing unnecessary portions 17 around the punched protective film-forming film 16. To. In the case of a protective film-forming sheet having a two-layer structure composed of the protective film-forming film 11 and the first release film 12, the protective film-forming film 11 is completely punched into a predetermined closed shape, and the first release film 12 is formed. A notch 14 is made so as not to be completely punched, a protective film forming film 16 having a predetermined closed shape remains on the first release film 12, and an unnecessary portion 17 around the periphery is removed. In the case of a protective film-forming sheet having a three-layer structure in which the protective film-forming film 11 is sandwiched between two release films (12, 13), the protective film-forming film 11 and one of the second release films 13 are used. A notch 14 is made so as not to completely punch the other first release film 12 into a predetermined closed shape, and the protective film forming film 16 having a predetermined closed shape remains on the first release film 12. Then, the unnecessary portion 17 and the second release film 13 around the periphery are removed.

The case of a sheet for forming a protective film having a two-layer structure will be described in more detail by taking as an example. As shown in FIG. 5, the protective film forming sheet 10 composed of the protective film forming film 11 and the first release film 12 is completely punched out of the protective film forming film 11 into a predetermined closed shape, and the first release film 12 is formed. A notch 14 is made so as not to be completely punched, and the protective film forming sheet is punched. This process is called a "punching process".

Next, in order to use the punched protective film forming sheet for attaching to the work, the unnecessary portion 17 around the protective film forming film 16 punched into a predetermined closed shape is removed (FIG. 6). .. This process is called a "scrap raising process". As a result, a laminated body having a protective film forming film 16 punched into a predetermined closed shape on the first release film 12 that can be used for attachment to the work is obtained.

In the case of the protective film forming sheet having a three-layer structure, in the punching process, there is another release film 13 (second release film 13) on the protective film forming film 11, and the second release film 13 is also predetermined. It is the same as the case of the protective film forming sheet having a two-layer structure, except that the second release film 13 is removed in the scrap raising step, which is completely punched into a closed shape.

As the protective film forming sheet, it is required that the punching process can be performed stably (work stability). In particular, after the protective film forming film is punched out, work stability in the scrap raising process for removing unnecessary parts is required. More specifically, in the scrap raising step, a problem that the protective film forming film 16 to be left is unintentionally peeled from the first release film 12 together with the unnecessary portion 17 (hereinafter, also referred to as “scrap raising defect”) occurs. It is required not to.

In order to solve such a problem, for example, Patent Document 1 proposes to control the peeling force between the release film and the protective film-forming film within a predetermined range.

International release WO2017 / 145735

When a scrap raising defect occurs, it is necessary to stop the production line and dispose of the defective product, which lowers the yield of the product and increases the cost. Therefore, it is required to further suppress the defective scrap raising.

The present inventors continued to search for the cause of the defective scrap raising, and obtained the following findings.

The protective film forming sheet 10 passes through a plurality of rollers such as a guide roller for the purpose of controlling the tension of the protective film forming sheet after the punching process and before the scrap raising process. At this time, as shown in FIG. 7, the protective film forming sheet 10 may be bent so that the upper side (the surface on which the die has entered) of the notch 14 is on the roller 19 side. As a result of bending, the width of the notch 14 becomes narrower, especially in the notch portion substantially parallel to the lateral direction of the sheet 10, and at the same time, the protective film forming film 16 is crushed and slightly deformed, which also partially acts. , The adjacent protective film forming film 16 and the unnecessary portion 17 may come into contact with each other and adhere to each other.

After passing through the roller 19, in many cases, the adhesive portion between the protective film forming film 16 and the unnecessary portion 17 is separated again, but may remain attached without being separated. When scraping is performed with the protective film-forming film 16 and the unnecessary portion 17 adhered to each other, the protective film-forming film 16 that should remain on the first release film 12 is removed together with the unnecessary portion 17 that should be removed. It peels off unintentionally, resulting in poor scrap raising.

INDUSTRIAL APPLICABILITY The present invention has been made in view of such an actual situation, and provides a protective film forming sheet and a method for manufacturing the same, which can sufficiently suppress scrap raising defects even when the depth of cut during punching is relatively narrow. The purpose.

Aspects of the present invention are as follows.
(1) Protective film forming film and
A long sheet having a first release film provided on one surface of the protective film forming film.
A protective film forming sheet having an adhesive force of 19 N / 25 mm or less 2 minutes after the two protective film forming films are attached at 23 ° C. with a load of 2 kgf.
(2) The protective film forming sheet according to (1), wherein the surface elastic modulus of the surface of the first release film in contact with the protective film forming film is 17 MPa or less.
(3) When the protective film forming sheet is viewed in a plan view, a notch is formed in the protective film forming sheet so that a part of the protective film forming sheet has a predetermined closed shape.
The protective film forming according to (1) or (2), wherein the notch penetrates the protective film forming film and reaches a part of the first release film in the thickness direction of the protective film forming sheet. Sheet.
(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) It has a step of forming a notch so that a part of the protective film forming sheet according to the above (1) or (2) has a predetermined closed shape.
A method for producing a punched protective film-forming sheet in which the cut penetrates the protective film-forming film and reaches a part of the first release film in the thickness direction of the protective film-forming sheet.
(6) The method for producing 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.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a protective film forming sheet and a method for manufacturing the same, which can sufficiently suppress scrap raising defects even when the depth of cut during punching is relatively narrow.

FIG. 1 is a schematic cross-sectional view of a protective film forming sheet according to an embodiment. FIG. 2 is a schematic cross-sectional view showing a state after the protective film forming sheet according to the embodiment is punched out. FIG. 3 is a schematic cross-sectional view of the protective film forming sheet according to another embodiment. FIG. 4 is a schematic cross-sectional view showing a state after punching and processing the protective film forming sheet according to another embodiment. FIG. 5 is a schematic perspective view of the protective film forming sheet after the punching process. FIG. 6 is a schematic perspective view showing a scrap raising process. FIG. 7 is a cross-sectional view showing a state in which the protective film forming sheet after the punching process has passed through the rollers. FIG. 8 is a schematic cross-sectional view of an example of a chip having a protective film obtained by forming a protective film forming film according to the present embodiment into a protective film. FIG. 9 is a schematic cross-sectional view for explaining a process of attaching the protective film forming sheet according to the present embodiment to the wafer. FIG. 10 is a schematic cross-sectional view for explaining a process of individualizing a wafer with a protective film. FIG. 11 is a schematic cross-sectional view for explaining a process of arranging a chip with a protective film on a substrate.

First, the main terms used in the present specification will be described.

The work is a plate-shaped body to which the protective film forming film according to the present embodiment is attached and processed. Examples of the work include wafers and panels. Specific examples thereof include semiconductor wafers and semiconductor panels. Examples of the work piece include a chip obtained by separating a wafer into individual pieces. Specifically, a semiconductor chip obtained by fragmenting a semiconductor wafer into pieces is exemplified. In this case, the protective film is formed on the back surface side of the wafer and the chip.

The "front surface" of a work such as a wafer refers to a surface on which a circuit or a convex electrode such as a bump is formed, and the "back surface" is a surface on which a circuit or an electrode (for example, a convex electrode such as a bump) is not formed. Point to.

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

The release film is a film that supports the protective film-forming film so that it can be peeled off. The term "film" does not limit the thickness, but is used in the concept of including a sheet.

The mass ratio in the description of the composition for the protective film forming film and the composition for the release agent layer is based on the active ingredient (solid content) and does not include the solvent unless otherwise specified.

Hereinafter, the present invention will be described in detail in the following order based on specific embodiments.

(1. Protective film forming film)
As shown in FIGS. 1 and 5, the protective film forming sheet 10 according to the present embodiment includes a protective film forming film 11 and a first release film 12 provided on one surface of the protective film forming film 11. It is a long sheet to have, and is usually wound in a roll shape.

The protective film forming film 11 is attached to the work and formed into a protective film to form a protective film for protecting the work or the work piece of the work.

"Forming a protective film" means that the protective film-forming film 11 is in a state having sufficient properties to protect the work or the workpiece of the work. Specifically, when the protective film-forming film according to the present embodiment is curable, "forming a protective film" means making an uncured protective film-forming film a cured product. In other words, the protective film-forming film is a cured product of the protective film-forming film, and is different from the protective film-forming film.

By superimposing the work on the curable protective film-forming film and then curing the protective film-forming film, the protective film can be firmly adhered to the work and a durable protective film can be formed.

When the protective film-forming film 11 is used in a non-curable state without containing a curable component, the protective film-forming film is protected when the protective film-forming film according to the present embodiment is attached to the work. It is filmed. 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 that the protective film-forming film may 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 the cured product include a thermosetting product and an energy ray cured product. In the present embodiment, it is more preferable that the protective film is a thermosetting product.

Further, it is preferable that the protective film-forming film has adhesiveness at room temperature (23 ° C.) or exhibits adhesiveness by heating. As a result, both can be bonded when the work is superposed on the protective film forming film. Therefore, positioning can be reliably performed before the protective film-forming film is cured.

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

In the present embodiment, the protective film-forming film is preferably one layer (single layer). If the protective film-forming film is composed of a plurality of layers, there is a risk of delamination due to the difference in thermal elasticity between the layers in the process of temperature change (during reflow processing or when using the device). The risk can be reduced if it is a layer.

The thickness of the protective film-forming film is not particularly limited, but is preferably 100 μm or less, more preferably 70 μm or less, further preferably 45 μm or less, and particularly preferably 30 μm or less. .. When the thickness of the protective film-forming film is within the above range, when the film passes through the roller after the punching process, even if the punched protective film-forming film and the unnecessary portion come into contact with each other and adhere to each other, the film passes through the roller. Later, it will be easier to separate again. The thickness of the protective film-forming film is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. When the thickness of the protective film-forming film is within the above range, the protective performance of the obtained protective film becomes good.

The thickness of the protective film-forming film means the thickness of the entire protective film-forming film. For example, the thickness of the protective film-forming film composed of a plurality of layers means the total thickness of all the layers constituting the protective film-forming film.

Hereinafter, the protective film formed on the chip as a work piece of the work will be described. Specifically, the protective film formed by forming the protective film-forming film according to the present embodiment into a protective film will be described using the chip 30 with a protective film shown in FIG.

As shown in FIG. 8, in the chip 30 with a protective film, the protective film 32 is formed on the back surface side (upper side in FIG. 8) of the chip 31, and the convex electrode is formed on the front surface side (lower side in FIG. 8) of the chip 31. 33 is formed.

A circuit is formed on the surface side of the chip 31, and the convex electrode 33 is formed so as to be electrically connected to the circuit. The chip 30 with a protective film is arranged so 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 substrate is electrically and mechanically bonded and mounted via the convex electrode 33. Examples of the convex electrode 33 include bumps and pillar electrodes.

(1.1 Adhesive force between protective film forming films)
In the present embodiment, by controlling the adhesive force when the protective film-forming films constituting the protective film-forming sheet are attached to each other within a predetermined range, poor scrap raising is suppressed. Specifically, it is characterized in that the adhesive force 2 minutes after the two protective film-forming films are attached at 23 ° C. with a load of 2 kgf is 19 N / 25 mm or less. The adhesive force is preferably 15 N / 25 mm or less, and more preferably 11 N / 25 mm or less. Further, if the adhesive force is too small, the holding performance of the work may be deteriorated. Therefore, the adhesive force is preferably 0.1 N / 25 mm or more, more preferably 1 N / 25 mm or more, and particularly preferably 3 N. / 25 mm or more. The reason why the adhesive force was measured 2 minutes after the protective film forming films were attached to each other is that the protective film forming sheet passes through the roller 19 in the device for raising scraps and attaching to the work. This is because the time when the cut portion is in contact with the roller 19 and is stopped is about 2 minutes.

By controlling the adhesive force between the protective film forming films within a predetermined range as described above, the protective film forming sheet is bent after the punching process, and the punched protective film forming film 16 and the unnecessary portion 17 adhere to each other. Even so, after the protective film-forming sheet has passed through the rollers, the protective film-forming film 16 and the unnecessary portion 17 are separated again, and the scrap raising defect is reduced.

(1.2 Composition for protective film forming 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 the protective film-forming film) contains at least the polymer component (A), the curable component (B), and the filler (E). It is preferably a resin composition. The polymer component is a component that can be regarded as being formed by a polymerization reaction of a polymerizable compound. Further, the curable component is a component capable of a curing (polymerization) reaction. In the present invention, the polymerization reaction also includes a polycondensation reaction.

Further, the component contained in the polymer component may also correspond to a curable component. In the present embodiment, when the composition for a protective film-forming film contains a component corresponding to both such a polymer component and a curable component, the composition for a protective film-forming film is a polymer component and a curable component. Considered to contain both ingredients.

(1.2.1 Polymer component)
The polymer component (A) gives the protective film-forming film an appropriate tack while having film-forming property (film-forming property), and ensures uniform attachment of the protective film-forming film to the work. The weight average molecular weight of the polymer component is usually in the range of 50,000 to 2 million, preferably 100,000 to 1.5 million, and particularly preferably 200,000 to 1,000,000. If the weight average molecular weight is too low, the adhesive force between the protective film-forming films tends to increase. On the other hand, if the weight average molecular weight is too high, the compatibility with other components deteriorates, and as a result, uniform film formation is hindered. As such a polymer component, for example, acrylic resin, urethane resin, phenoxy resin, silicone resin, saturated polyester resin and the like are used, and acrylic resin is particularly preferably used.

In the present specification, the "weight average molecular weight" is a polystyrene-equivalent value measured by a gel permeation chromatography (GPC) method unless otherwise specified. For the measurement by such a method, for example, the high-speed GPC apparatus "HLC-8120 GPC" manufactured by Tosoh Corporation is used with the high-speed columns "TSK grade volume H _XL -H", "TSK Gel GMH _XL ", and "TSK Gel G2000 H _XL ". (The above, all manufactured by Tosoh Corporation) are connected in this order, and the detector is used as a differential refractometer under the conditions of a column temperature of 40 ° C. and a liquid feeding rate of 1.0 mL / min.

Examples of the acrylic resin include a (meth) acrylic acid ester copolymer composed of a (meth) acrylic acid ester monomer and a structural unit derived from a (meth) acrylic acid derivative. Here, examples of the (meth) acrylic acid ester monomer include (meth) acrylic acid alkyl esters having an alkyl group having 1 to 18 carbon atoms, and specifically, (meth) methyl acrylate and (meth). Examples thereof include ethyl acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Examples of the (meth) acrylic acid derivative include (meth) acrylic acid, glycidyl (meth) acrylic acid, and hydroxyethyl (meth) acrylate.

In the present embodiment, it is preferable to introduce a glycidyl group into the acrylic resin by using glycidyl methacrylate or the like. The compatibility between the acrylic resin into which the glycidyl group is introduced and the epoxy resin as a thermosetting component described later is improved, the glass transition temperature (Tg) after curing of the protective film-forming film is increased, and the heat resistance is improved. .. Further, in the present embodiment, it is preferable to introduce a hydroxyl group into the acrylic resin by using hydroxyethyl acrylate or the like in order to control the adhesiveness to the work and the adhesive physical characteristics.

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., still more preferably −10 ° C. to 25 ° C., and particularly preferably −. It is 5 ° C to 20 ° C. By setting the glass transition temperature of the acrylic resin in the above range, the flowability of the protective film forming film and the protective film during heating is suppressed, so that a smooth protective film can be easily obtained. If the glass transition temperature is too low, the adhesive force between the protective film-forming films tends to increase. If the glass transition temperature is too high, the compatibility with other components deteriorates, and as a result, uniform film formation is hindered.

（式中、Ｔｇはアクリル樹脂のガラス転移温度であり；ｍは２以上の整数であり；Ｔｇｋはモノマーｍのホモポリマーのガラス転移温度であり；Ｗｋはアクリル樹脂における、モノマーｍから誘導された構成単位ｍの質量分率であり、ただし、Ｗｋは下記式を満たす。）

（式中、ｍ及びＷｋは、前記と同じである。） When the acrylic resin has m types (m is an integer of 2 or more), the glass transition temperature of the acrylic resin can be calculated as follows. That is, when the m-type monomers that induce the constituent units in the acrylic resin are sequentially assigned any unique number from 1 to m and named as "monomer m", the glass transition of the acrylic resin is performed. The temperature (Tg) 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 of 2 or more; Tgk is the glass transition temperature of the homopolymer of the monomer m; Wk is derived from the monomer m in the acrylic resin. It is a mass fraction of the constituent unit m, where Wk satisfies the following formula.)

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

As Tgk, the values described in the polymer data handbook, the adhesive handbook, the Polymer Handbook, and the like can be used. For example, the Tgk of the methyl acrylate homopolymer is 10 ° C, the Tgk of the n-butyl acrylate homopolymer is -54 ° C, the Tgk of the methyl methacrylate homopolymer is 105 ° C, and the Tgk of the 2-hydroxyethyl acrylate homopolymer is-. At 15 ° C, the Tgk of the glycidyl methacrylate homopolymer is 41 ° C, and the Tgk of the 2-ethylhexyl acrylate is −70 ° C.

When the total weight of the composition for the protective film forming film is 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, and more preferably 10 to 60 parts by mass. Parts, more preferably 12 to 55 parts by mass, still more preferably 14 to 50 parts by mass, and particularly preferably 15 to 45 parts by mass. When the content of the polymer component is within the above range, the amount of the low molecular weight component that increases the adhesive force between the protective film-forming films is limited to an appropriate range. Easy to design.

(1.2.2 Thermosetting component)
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 cured by irradiation with energy rays, the protective film-forming film according to the present embodiment contains a filler and a colorant, which will be described later, so that the light transmittance is lowered. Therefore, for example, when the thickness of the protective film forming film becomes thick, the energy ray curing tends to be insufficient.

On the other hand, the thermosetting protective film-forming film can be sufficiently cured by heating even if its thickness becomes thick, so that a protective film having high protective performance can be formed. Further, by using a normal heating means such as a heating oven, a large number of protective film forming films can be heated at once and thermoset.

Therefore, in this embodiment, it is desirable that the curable component is thermosetting. That is, the protective film-forming film according to this embodiment is preferably thermosetting.

Whether or not the protective film-forming film is thermosetting can be determined as follows. First, the protective film-forming film at room temperature (23 ° C.) is heated to a temperature exceeding the room temperature, and then cooled to the room temperature to obtain a protective film-forming film after heating and cooling. Next, when the hardness of the protective film-forming film after heating and cooling is compared with the hardness of the protective film-forming film before heating at the same temperature, if the protective film-forming film after heating and cooling is harder, , This protective film forming film is judged to be thermosetting.

As the thermosetting component, for example, an epoxy resin, a thermosetting polyimide resin, an unsaturated polyester resin and a mixture thereof are preferably used. The thermosetting polyimide resin is a general term for low molecular weight, low viscosity monomers or precursor polymers that form a polyimide resin by thermosetting. Non-limiting examples of thermosetting polyimide resins are described, for example, in the Journal of the Textile Society, "Fibers and Industry", Vol.50, No.3 (1994), P106-P118.

Epoxy resin as a thermosetting component has the property of forming a three-dimensional network when heated and forming a strong film. As such an epoxy resin, various known epoxy resins are used. In the present embodiment, the molecular weight (formula) 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, and 300 or more and less than 3,000. The epoxy equivalent of the epoxy resin is preferably 50 to 5000 g / eq, more preferably 100 to 2000 g / eq, and even more preferably 150 to 1000 g / eq.

Specific examples of such an epoxy resin include glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenylnovolac, and cresolnovolac; and glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; Glycidyl ethers of carboxylic acids such as phthalic acid, isophthalic acid, tetrahydrophthalic acid; glycidyl-type or alkylglycidyl-type epoxy resins in which active hydrogen bonded to a nitrogen atom such as aniline isocyanurate is replaced with a glycidyl group; vinylcyclohexanediepoxide, 3,4-Epoxycyclohexylmethyl-3,4-dicyclohexanecarboxylate, 2- (3,4-epoxy) cyclohexyl-5,5-spiro (3,4-epoxy) cyclohexane-m-dioxane, etc. The so-called alicyclic epoxide in which an epoxy is introduced by, for example, oxidizing a carbon-carbon double bond in a molecule can be mentioned. In addition, an epoxy resin having a biphenyl skeleton, a dicyclohexadiene skeleton, a naphthalene skeleton, or the like can also be used.

When a thermosetting component is used as the curable component (B), it is preferable to use a curing agent (C) in combination as an auxiliary agent. As the curing agent for the epoxy resin, a heat-active latent epoxy resin curing agent is preferable. The "heat-active latent epoxy resin curing agent" is a type of curing agent that is difficult to react with an epoxy resin at room temperature (23 ° C.), is activated by heating at a certain temperature or higher, and reacts with the epoxy resin. The method for activating the heat-active latent epoxy resin curing agent is to generate active species (anions, cations) by a chemical reaction by heating; the epoxy resin is stably dispersed in the epoxy resin near room temperature and is at high temperature. There are methods such as a method of incompatible with and dissolving with and starting a curing reaction; a method of eluting at a high temperature with a molecular sieve-encapsulated type curing agent to start a curing reaction; and a method of using microcapsules.

Among the illustrated methods, a method in which the material is stably dispersed in the epoxy resin near room temperature and is compatible with and dissolved in the epoxy resin at a high temperature to start the curing reaction is preferable.

Specific examples of the heat-active latent epoxy resin curing agent include various onium salts, refractory active hydrogen compounds such as dibasic acid dihydrazide compounds, dicyandiamides, amine adduct curing agents, and imidazole compounds. These heat-active latent epoxy resin curing agents may be used alone or in combination of two or more. In this embodiment, dicyandiamide is particularly preferable.

Further, as the curing agent for the epoxy resin, a phenol resin is also preferable. As the phenol resin, a condensate of phenols such as alkylphenol, polyhydric phenol, and naphthol and aldehydes is used without particular limitation. Specifically, phenol novolac resin, o-cresol novolak resin, p-cresol novolak resin, t-butylphenol novolak resin, dicyclopentadiencresol resin, polyparavinylphenol resin, bisphenol A type novolak resin, or modified products thereof. Etc. are used.

The phenolic hydroxyl group contained in these phenolic resins can be easily added and reacted with the epoxy group of the epoxy resin by heating to form a cured product having 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, and more preferably 0.2 to 15 parts by mass with respect to 100 parts by mass of the epoxy resin. Particularly preferably, it is 0.3 to 10 parts by mass. By setting the content of the curing agent (C) in the above range, the network structure of the protective film becomes dense, so that it is easy to obtain the performance of protecting the work as the protective film.

When dicyandiamide is used as the curing agent (C), it is preferable to further use the curing accelerator (D) in combination. Examples of the curing accelerator include 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxy. Imidazoles such as methylimidazole (imidazole in which one or more hydrogen atoms are substituted with a group other than the hydrogen atom) are preferable. Among these, 2-phenyl-4-methyl-5-hydroxymethylimidazole is particularly preferable.

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, with respect to 100 parts by mass of the epoxy resin. It is preferably 0.3 to 10 parts by mass. By setting the content of the curing accelerator (D) in the above range, the network structure of the protective film becomes dense, so that it is easy to obtain the performance of protecting the work as the protective film.

The total content of the thermosetting component and the curing agent when the total weight of the composition for the protective film forming film is 100 parts by mass is preferably 3 to 80 parts by mass, more preferably 5 to 60 parts by mass. It is preferably 7 to 50 parts by mass, more preferably 9 to 40 parts by mass, and particularly preferably 10 to 30 parts by mass. When the thermosetting component and the curing agent are blended in such a ratio, an appropriate tack is exhibited before curing, and the pasting work can be stably performed. Further, after curing, it is easy to obtain the performance of protecting the work as a protective film.

When a low molecular weight compound is used as a thermosetting component and a curing agent, the tack of the protective film-forming film may be increased and the adhesive force between the protective film-forming films may be increased. Therefore, it is desirable that the types of the thermosetting component and the curing agent and the blending amount thereof are selected so as to control the tack to an appropriate value within the above range.

(12.3 Energy ray curable component)
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 uncured and adhesive. ..

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

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

When a low molecular weight compound is used as the energy ray-curable component, the tack of the protective film-forming film may increase, and the adhesive force between the protective film-forming films may increase. Therefore, it is desirable to select the type of energy ray-curable component and the blending amount thereof so as to control the tack to an appropriate value.

(12.4 Filler)
Since the protective film-forming film contains the filler (E), the protective film obtained by forming the protective film-forming film into a protective film can easily adjust the thermal expansion coefficient, and this thermal expansion coefficient can be used as the thermal expansion coefficient of the work. By bringing it closer to, the adhesive reliability of the package obtained by using the protective film forming film is further improved. Further, when the protective film forming film contains the filler (E), a hard protective film can be obtained, the hygroscopicity of the protective film can be further reduced, and the adhesive reliability of the package is further improved.

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

Preferred inorganic fillers include, for example, powders of silica, alumina, talc, calcium carbonate, red iron oxide, silicon carbide, boron nitride and the like; spherical beads of these inorganic fillers; surface modified products of these inorganic fillers; these. Single crystal fiber as an inorganic filler; glass fiber and the like can be mentioned. Among these, silica and surface-modified silica are preferable. The surface-modified silica is preferably surface-modified with a coupling agent, and more preferably surface-modified with a silane coupling agent.

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

By setting the average particle size of the filler to the above value, the handleability of the composition for the protective film-forming film is improved. Therefore, the quality of the composition for the protective film-forming film and the protective film-forming film is likely to be stable.

In the present specification, the "average particle size" means the value of the particle size (D50) at an integrated value of 50% in the particle size distribution curve obtained by the laser diffraction / scattering method, unless otherwise specified.

When the total weight of the composition for the protective film forming film is 100 parts by mass, the content of the filler is preferably 15 to 80 parts by mass, more preferably 30 to 75 parts by mass, still more preferably 40 to 70 parts by mass. Particularly preferably, it is 45 to 65 parts by mass.

By setting the content of the filler to the above value, it is easy to control the adhesive force between the protective film-forming films within an appropriate range. If the content of the filler is too small, the tack of the protective film-forming film increases, and the adhesive force between the protective film-forming films increases excessively. On the other hand, if the amount of the filler is too large, the shape-retaining property of the protective film-forming film deteriorates, the film cannot keep its shape due to bending by the roller, and the protective film-forming film becomes tacky and adhesive to the work. May drop excessively.

Further, the protective film forming film preferably contains two or more kinds of fillers. That is, the filler (E) is preferably a mixture of two or more kinds of fillers. "Containing two or more types of fillers" may include two or more types of fillers having different materials, or may include two or more types of fillers having different average particle sizes.

In the present embodiment, it is preferable to include two or more kinds of fillers having different average particle sizes. By including the fillers having different average particle sizes in the protective film forming film, the fillers having a small average particle size can be easily arranged in the gaps between the fillers having a large average particle size. As a result, it becomes easy to keep the adhesive force between the protective film forming films within the above range while obtaining the above effect.

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

Whether or not the protective film or the protective film-forming film contains two or more kinds of fillers having different average particle sizes can also be confirmed by observing the cross section of the protective film or the protective film-forming film.

(1.2.5 Coupling agent)
The protective film-forming film preferably contains a coupling agent (F). By containing the coupling agent, after the protective film forming film is cured, the adhesiveness between the protective film and the work can be improved without impairing the heat resistance of the protective film, and water resistance (moisture and heat resistance) can be improved. Can be improved. As the coupling agent, a silane coupling agent is preferable from the viewpoint of its versatility and cost merit.

Examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ- (methacryloxy). Propyl) Trimethoxysilane, γ-Aminopropyltrimethoxysilane, N-6- (Aminoethyl) -γ-Aminopropyltrimethoxysilane, N-6- (Aminoethyl) -γ-Aminopropylmethyldiethoxysilane, N -Phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfan, methyltri Examples thereof include methoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazolesilane. These can be used alone or in admixture of two or more.

The content of the coupling agent when the total weight of the composition for the protective film forming film is 100 parts by mass is preferably 0.01 to 20 parts by mass, 0.1 to 10 parts by mass, and 0.2 to 5 parts. It is a mass part and 0.3 to 3 parts by mass.

(12.6 colorant)
The protective film-forming film preferably contains a colorant (G). As a result, the back surface of the workpiece such as a chip is concealed, so that various electromagnetic waves generated in the electronic device can be blocked and the malfunction of the workpiece such as the chip can be reduced. In addition, if a scrap raising defect occurs, it can be immediately detected visually.

As the colorant (G), for example, known ones such as inorganic pigments, organic pigments, and organic dyes can be used. Inorganic pigments are preferred in this embodiment.

Examples of the inorganic pigment include carbon black, cobalt dye, iron dye, chromium dye, titanium dye, vanadium dye, zirconium dye, molybdenum dye, ruthenium dye, platinum dye, and ITO (indium). Examples thereof include a tin oxide) dye and an ATO (antimonth tin oxide) dye. Among these, it is particularly preferable to use carbon black. According to carbon black, electromagnetic waves in a wide wavelength range can be blocked.

The amount of the colorant (particularly 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 composition for the protective film-forming film. When the total weight of the product is 100 parts by mass, the content of the colorant is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and more preferably 0.05 to 4 parts by mass. Is.

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

(12.7 Other additives)
The composition for a protective film-forming film can be used as other additives, for example, a photopolymerization initiator, a cross-linking agent, a plasticizer, an antistatic agent, an antioxidant, and a gettering agent, as long as the effects of the present invention are not impaired. , Antistatic agent, release agent and the like may be contained.

However, the content of the release agent in the composition for the protective film-forming film is preferably less than a predetermined amount. In the present embodiment, it is preferably less than 0.00099% by mass with respect to the total mass of the protective film-forming film. If the content of the release agent is too large, the adhesive reliability between the protective film and the work tends to decrease. Examples of the release agent include an alkyd-based release agent, a silicone-based release agent, a fluorine-based release agent, an unsaturated polyester-based release agent, a polyolefin-based release agent, and a wax-based release agent.

(1.2.8 Control of adhesive force between protective film forming films)
As described above, the present embodiment is characterized in that the adhesive force when the protective film forming films constituting the protective film forming sheet are bonded to each other is controlled within a predetermined range, thereby suppressing a scrap raising defect. ing.

The adhesive force between the protective film-forming films can be controlled by the type of each component constituting the protective film-forming film and the blending amount thereof.

When the weight average molecular weight of the polymer component (A) is low, the adhesive force tends to increase. When the glass transition temperature of the polymer component (A) is low, the adhesive force tends to increase. Further, when a low molecular weight compound is used as the curable component (B), the curing agent (C), the curing accelerator (D), and the energy ray curable component, the adhesive force tends to increase. When the amount of the filler (E) is large, the adhesive force tends to decrease.

Adhesive force can also be controlled by partially curing the protective film-forming film. For example, by partially curing the curable component (B), the adhesive force can be reduced. The timing at which the protective film-forming film is partially cured is not particularly limited, and may be, for example, at the stage before passing through the roller 19 at the time of punching the protective film-forming sheet. However, from the viewpoint of setting the peeling forces F1 and F2 described later in an appropriate range and the adhesiveness to the work, it is preferable that the protective film-forming film is not partially cured as in the examples described later.

(2. Protective film forming sheet)
Before use, the protective film-forming film is wound in the form of a two-layered protective-forming sheet 10 in which the protective film-forming film 11 is releasably laminated on the first release film 12, as shown in FIG. , May be stored. Further, as shown in FIG. 3, the form of the protective film forming sheet 20 having a three-layer structure in which the protective film forming film 11 is sandwiched between the two release films (the first release film 12 and the second release film 13) (the first release film 12 and the second release film 13). In another embodiment), it may be collected and stored. The release film is peeled off when the protective film-forming film is used.

The protective film forming sheet is long and is wound into a roll for storage and transportation. As such a protective film forming sheet, a protective film forming sheet in which the protective film forming film is preliminarily punched into a shape substantially the same as that of the work is also known. In such a punched protective film forming sheet, the protective film forming film 16 punched into a predetermined closed shape is laminated on the first release film 12 (FIG. 2) or two release films. It is sandwiched between (12, 13) (Fig. 4).

The first release film may be composed of one layer (single layer) or two or more layers of a base material, or the surface of the base material may be peeled from the viewpoint of controlling the peelability. That is, the surface of the base material may be modified, or a material not derived from the base material may be formed on the surface of the base material. In the present embodiment, the first release film preferably has a base material and a release agent layer. By having the release agent layer, it is easy to control the physical properties of the surface on which the release agent layer is formed in the first release film. In the present embodiment, a coating agent containing a composition for a release agent layer, which will be described later, is applied to one surface of the base material, and then the coating film is dried and cured to form a release agent layer. As a result, the first release film is obtained.

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

When the lower limit of the thickness of the first release film 12 is the above value, the cutting blade penetrates the first release film 12 and the first release film 12 is cut when the protective film forming film is cut out by the cutting blade. It can be prevented from being lost. Further, when the upper limit value of the thickness is the above value, the protective film forming sheet 10 is fed out and the protective film forming film 11 is cut out and conveyed to the next step. Although it passes through a roller such as a guide roller inside, it is possible to prevent the protective film forming film 11 from peeling from the first release film 12.

The thickness of the first release film 12 means the thickness of the entire first release film. For example, the thickness of the first release film composed of a plurality of layers means the total thickness of all the layers constituting the first release film.

Examples of the base material of the first release film 12 include a resin film and paper. Resins for the resin film include polyethylene terephthalate, polyethylene, polypropylene, polybuden, polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polybutylene terephthalate, polyurethane, ethylene-vinyl acetate copolymer, ionomer resin, and ethylene. Examples thereof include (meth) acrylic acid copolymers, polystyrenes, polycarbonates, fluororesins, low-density polyethylenes, linear low-density polyethylenes, and triacetyl celluloses. Examples of the paper include high-quality paper, coated paper, glassine paper, and laminated paper. These may be used alone or in combination of two or more. Among these, polyethylene terephthalate film is preferable from the viewpoint of low cost and rigidity.

At least one surface (the surface laminated with the protective film-forming film) of the first release film 12 may be peeled with the release agent layer composition. The thickness of the release agent layer is preferably 30 nm or more and 200 nm or less, and more preferably 50 nm or more and 180 nm or less.

The surface elastic modulus (23 ° C.) of the surface of the first release film 12 in contact with the protective film forming film 11 is preferably 17 MPa or less, more preferably 14 MPa or less, more preferably 13 MPa or less, and particularly preferably 12 MPa or less. The surface elastic modulus is an index of the susceptibility to deformation of the surface. By setting the surface elastic modulus of the surface of the first release film 12 in contact with the protective film forming film 11 within the above range, when the die is pushed in and then pulled out in the punching process, the protective film forming film 11 and the first It is possible to suppress the occurrence of floating (peeling of about 1 to 4 mm) between the release film 12 and the film 12. This is because the surface of the first release film 12 is relatively flexible, so that the surface of the first release film follows the deformation of the protective film-forming film even if there is compression by punching and decompression due to its desorption. it is conceivable that. By suppressing the occurrence of floating, it is possible to further reduce the defective raising of scraps. The lower limit of the surface elastic modulus of the surface of the first release 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 3 MPa or more. It is more preferably 4 MPa or more, and particularly preferably 5 MPa or more.

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

In order to keep the peeling force F1 described later within an appropriate range and the surface elastic coefficient of the first peeling film 12 within the above range, in the present embodiment, the composition for the release agent layer is, for example, an alkyd-based release agent. Silicone-based mold release agents, fluorine-based mold release agents, unsaturated polyester-based mold release agents, polyolefin-based mold release agents, and wax-based mold release agents are preferable, and among them, silicone-based mold release agents are preferable, and silicone-based mold release agents are particularly preferable. It is preferable to include an agent and a heavy release additive.

As the silicone release agent, a silicone release agent containing silicone having dimethylpolysiloxane as a basic skeleton can be used.

The silicone may be any of an addition reaction type, a condensation reaction type, and an energy ray curable type such as an ultraviolet curable type and an electron beam curable type, but an addition reaction type silicone is preferable. The addition reaction type silicone has merits such as high reactivity and excellent productivity, a small change in peeling force after production, and no curing shrinkage as compared with the condensation reaction type.

As a specific example of the addition reaction type silicone, an organopoly having two or more alkenyl groups having 2 to 10 carbon atoms such as a vinyl group, an allyl group, a propenyl group, and a hexenyl group at the terminal and / or side chain of the molecule. Examples include siloxane. From the viewpoint of lowering the surface elastic modulus, the number of alkenyl groups in the addition reaction type silicone is preferably small.

The content of silicone composed of dimethylpolysiloxane when the total weight of the composition for the release agent layer (excluding the catalyst described later) is 100 parts by mass is preferably less than 100 parts by mass, more preferably less than 90 parts by mass. It is more preferably less than 80 parts by mass, and particularly preferably less than 70 parts by mass.

When using such an addition reaction type silicone, it is preferable to use a cross-linking agent and a catalyst in combination.

Examples of the cross-linking agent include organopolysiloxane having a hydrogen atom bonded to at least two silicon atoms in one molecule. From the viewpoint of lowering the surface elastic modulus, it is preferable that the content of the cross-linking agent in the composition for the release agent layer is small.

Specific examples of the cross-linking agent include dimethylhydrogensiloxy group-terminated closure dimethylsiloxane-methylhydrogensiloxane copolymer, trimethylsiloxy group-terminated closure dimethylsiloxane-methylhydrogensiloxane copolymer, and trimethylsiloxy group-terminated closure methylhydrogen. Examples thereof include polysiloxane and poly (hydrogencil sesquioxane).

Examples of the catalyst include fine particle platinum, fine particle platinum adsorbed on a carbon powder carrier, platinum chloride acid, alcohol-modified platinum chloride acid, an olefin complex of platinum chloride acid, palladium, and platinum group metal compounds such as rhodium. Can be mentioned.

By using such a catalyst, the curing reaction of the composition for the release agent layer can proceed more efficiently.

The content of the silicone-based mold release agent when the total weight of the composition for the release agent layer (excluding the catalyst) is 100 parts by mass is from the viewpoint of keeping the surface elastic modulus within the above-mentioned range, and the release force F1 described later. Is preferably within an appropriate range of 30 to 100 parts by mass, more preferably 50 to 100 parts by mass.

The heavy peeling additive is used to increase the peeling force F1 described later. Examples of the heavy peeling additive include organosilanes such as silicone resin and silane coupling agent, and among these, silicone resin is preferably used.

As the silicone resin, for example, it is preferable to use an MQ resin containing an M unit which is a monofunctional siloxane unit [R ₃ SiO _1/2 ] and a Q unit which is a tetrafunctional siloxane unit [SiO _4/2 ]. The three Rs in the M unit independently represent a hydrogen atom, a hydroxyl group, or an organic group. From the viewpoint of facilitating the suppression of silicone migration, one or more of the three Rs in the M unit is preferably a hydroxyl group or a vinyl group, and more preferably a vinyl group. From the viewpoint of lowering the surface elastic modulus, it is preferable that the content of the silicone resin (particularly MQ resin) in the composition for the release agent layer is small.

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

The composition for a release agent layer is preferably used as a coating agent containing a diluting solvent together with the above-mentioned various active ingredients from the viewpoint of adjusting the viscosity and improving the coatability on the substrate. As used herein, the term "active ingredient" refers to a component contained in a coating agent containing a target composition, excluding a diluting solvent.

Examples of the diluting solvent include aromatic hydrocarbons such as toluene, fatty acid esters such as ethyl acetate, ketones such as methyl ethyl ketone, and organic solvents such as aliphatic hydrocarbons such as hexane and heptane. These diluting solvents may be used alone or in combination of two or more.

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

The composition for the release agent layer may contain additives generally used in the release agent layer as long as the effects of the present invention are not impaired. Examples of such additives include dyes and dispersants.

In the protective film forming sheet 10 according to the present embodiment, it is preferable that the protective film forming film 11 is punched into a predetermined shape. That is, when the protective film forming sheet 10 is viewed in a plan view, a notch 14 may be formed in the protective film forming sheet so that a part of the protective film forming sheet 10 has a predetermined closed shape. preferable. The shape of the protective film-forming film after punching is preferably smaller than the shape of the work from the viewpoint that the protective film-forming film does not protrude from the work when the protective film-forming film is attached to the work.

(3. Manufacturing method of protective film forming sheet)
The method for producing the protective film-forming film is not particularly limited. The film is produced by using a coating agent containing the above-mentioned composition for a protective film-forming film. The coating agent is prepared by mixing the components constituting the protective film-forming film composition by a known method.

The obtained coating agent is applied to the peeling surface of the first release film 12 using a coating machine such as a roll coater, a knife coater, a roll knife coater, an air knife coater, a die coater, a bar coater, a gravure coater, and a curtain coater. And dried to obtain the protective film forming sheet 10 according to the present embodiment, which has the protective film forming film 11 on the first release film 12. The coating agent may be applied onto another resin film, dried, and the obtained protective film-forming film may be transferred to the first release film. When the protective film forming sheet 20 according to another embodiment is obtained, the second release film 13 is attached to the exposed surface of the protective film forming film 11 laminated with the first release film 12, and the two release films are attached. A protective film-forming sheet 20 in which the protective film-forming film 1 is sandwiched is obtained.

(4. Manufacturing method of punched protective film forming sheet)
A method of punching out the protective film forming sheet 10 and obtaining the protective film forming film 16 punched into a predetermined closed shape on the first release film 12 will be described.

(4.1 Punching process)
First, as shown in FIG. 1, a protective film forming sheet 10 that has not been punched is prepared. From the surface of the protective film forming sheet 10 on the protective film forming film 11 side, a cut 14 is made so as to penetrate the protective film forming film 11 by a die (not shown) and reach a part of the surface of the first release film 12. Put in. The operation of making a cut so that it reaches a part of the surface and not cutting it completely is called a half cut. As a result, a notch 14 is formed on a part of the surface of the protective film forming sheet 10 so as to have a predetermined closed shape (see FIGS. 2 and 5). Here, the predetermined closed shape has substantially the same shape as the wafer when the protective film-forming film is transferred to the semiconductor wafer. That is, the notch 14 is formed so as to have substantially the same shape as the shape of the work to which the protective film forming film 11 is attached or the region where the protective film should be formed. This process is called a "punching process".

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 an unnecessary portion 17 continuous around the protective film forming film 16. The protective film forming film 16 punched into a predetermined closed shape is provided at a plurality of places along the longitudinal direction of the protective film forming sheet 10.

In the punching process, a known punching die can be appropriately used. The punching process is performed by completely cutting the protective film forming film 11 and half-cutting the first release film 12 so as not to completely cut it.

As shown in FIGS. 2 and 4, the cross-sectional shape of the notch 14 is substantially wedge-shaped, and the width of the notch 14 is wide on the upper surface side of the protective film forming film 11 into which the die enters, and the lower surface side (protective film forming film 11). And at the interface with the first release film 12), it becomes narrower. The width of the notch 14 is not particularly limited, but from the viewpoint of preventing contact and adhesion between the punched protective film forming film 16 and the unnecessary portion 17, or from the viewpoint of shortening the contact and adhesion time. The width D of the notch 14 in the lower surface portion of the protective film forming film 11 (that is, the upper surface portion of the first release film 12) is preferably 8 μm or more, more preferably 10 μm or more, and more preferably 15 μm or more. Is more preferable, and 20 μm or more is particularly preferable. The width D can be measured as the width of the cut in the upper surface portion of the first release film 12 in the cross section by cutting the protective film forming sheet in the thickness direction. The upper limit of the width D is not particularly limited, but considering the width of the cutting blade capable of reliably cutting the protective film forming film, it is usually 100 μm or less, preferably 80 μm or less, more preferably 60 μm or less, still more preferably 40 μm or less. Is. In order to form such a notch 14, it is preferable to use a die having a cutting edge having a relatively wide cutting edge at the tip portion as the die.

The protective film forming sheet 10 punched through the above steps is obtained. When the punched protective film forming sheet 10 is viewed from the upper surface of the protective film forming film 11 in a plan view, a part of the protective film forming sheet has a predetermined closed shape (for example, substantially the same shape as the planar shape of the semiconductor wafer). ) Is formed in the protective film forming sheet, and the notch 14 reaches a part of the first release film 12 in the thickness direction of the protective film forming sheet 10. That is, a notch is also formed on the surface of the first release film 12 in contact with the protective film forming film 11. By allowing the cutting blade to reach the first release film 12, the protective film forming film 11 can be completely cut.

(4.2 scrap raising process)
The protective film forming sheet 10 passes through a plurality of rollers such as a guide roller for the purpose of controlling the tension of the protective film forming sheet after the punching process and before the scrap raising process.

In the scrap raising step, as shown in FIG. 6, the continuous unnecessary portion 17 is peeled from the first release film 12, and the punched protective film forming film 16 remains on the first release film 12. The peeled unnecessary portion 17 is taken up by a disposal roller.

According to the protective film forming sheet 10 according to the present embodiment, when passing through the roller 19 or the like after the punching process, the punched protective film forming film 16 and the unnecessary portion 17 come into contact with each other and adhere to each other. However, since the adhesive force between the protective film-forming films is low, the protective film-forming film 16 and the unnecessary portion 17 are separated again after passing through the rollers. As a result, the scrap raising defect in the scrap raising process is suppressed.

The punched protective film forming sheet 10 may be rolled up, stored and transported.

(5. Work processing method)
As an example of the processing method of the work using the punched protective film forming sheet according to the present embodiment, a chip with a protective film obtained by processing a wafer to which the protective film forming film is attached is arranged on the substrate. The method of manufacturing the package will be described.

The method for manufacturing the apparatus according to the present embodiment includes at least the following steps 1 to 9.
Step 1: Punching of the protective film forming sheet 10 Step 2: Step of passing the punched protective film forming sheet between the rollers Step 3: Raise the unnecessary part 17 of the protective film forming sheet 10 Step 4: Protective film forming film 11 of the protective film forming sheet 10 is attached to the back surface of the wafer Step 5: Protective film forming the attached protective film forming film Step 6: Protective film or protective film forming film Step 7: A wafer having a protective film or a protective film forming film on the back surface is individualized to obtain a plurality of protective films or chips with a protective film forming film Step 8: Protective film or Step 9 of arranging the chip with the protective film forming film on the substrate: Step of heating the substrate with the protective film or the chip with the protective film forming film arranged on the substrate.

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

The manufacturing method of the apparatus having the above-mentioned steps 1 to 9 will be described with reference to the drawings.

2, FIG. 4, and FIG. 5 show an outline of step 1 as described above. FIG. 6 shows an outline of step 3.
As shown in FIG. 9, the protective film forming film 11 of the protective film forming sheet 10 is attached to the back surface of the wafer 21 (step 4). Then, the attached protective film forming film 11 is formed into a protective film 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 may be heated at a predetermined temperature for an appropriate time. When the protective film forming film 11 is energy ray curable, an energy ray transmissive film may be used as the first release film 12 and energy rays may be incident from the first release film 12 side.

The protective film-forming film 11 may be cured after the dicing step described later, or the chip with the protective film-forming film may be picked up from the dicing sheet and then the protective film-forming film 11 may be cured.

Next, the wafer 21 with a protective film is transferred onto a known dicing sheet 22, and the wafer 21 with a protective film is diced to obtain a chip 31 having a protective film 32 (chip 30 with a protective film) as shown in FIG. (Step 7). After that, the dicing sheet 22 is expanded in the plane direction as needed, and the chip 30 with a protective film is picked up from the dicing sheet 22 by a suction collet or the like.

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

As shown in FIG. 11, the chip 30 with a protective film conveyed in the next step is conveyed to the substrate 50 by the adsorption collet, is detached from the adsorption collet at the terminal portion on the substrate, and is a convex electrode such as a bump. The 33 and the terminal portion such as a pad are arranged at a connectable position (step 8). At this time, another chip different from the chip 30 with the protective film may be mounted on the substrate 50. Therefore, a plurality of chips may be mounted on this substrate.

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

In the reflow process, the convex electrode 33 of the protective film-attached chip 30 is melted and electrically and mechanically bonded to the terminal portion on the substrate, and the protective film-attached chip 30 is mounted on the substrate.

(6. Modification example)
The embodiment of the present invention has been described above by taking as an example a two-layer structure protective film forming sheet having the protective film forming film 11 on the first release film 12, but the exposed surface of the protective film forming film 11 has been described. The second release film 13 may be laminated. That is, the protective film-forming sheet may be a protective film-forming sheet 20 in which the protective film-forming film 11 is sandwiched between the first release film 12 and the second release film 13 (FIG. 3). , See Figure 4). In that case, the second release film 13 may be peeled off before the protective film forming film 11 is attached to the work.

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

Further, in the present embodiment, in the protective film forming sheet 20, the peeling force of the first release film 12 from the protective film forming film 11 is set to F1, and the peeling force of the second release film 13 described later from the protective film forming film 11 is set. When the force is F2, it is preferable that F1 and F2 satisfy the relationship of F1> F2. By satisfying such a relationship, when the second release film 13 is removed from the protective film forming sheet 20, the protective film forming film 16 that should remain is not removed together with the second release film 13, and the protective film is formed. It becomes easy to leave the film 16 on the first release film 12, and it is possible to further suppress scrap raising defects.

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

The peeling force F1 is preferably 50 mN / 100 mm or more, more preferably 70 mN / 100 mm or more, more preferably 90 mN / 100 mm or more, still more preferably 110 mN / 100 mm or more, and particularly preferably 130 mN / 100 mm or more. When F1 is within the above range, it is possible to prevent the protective film forming film 11 and the first release film 12 from being unintentionally separated.

The adjustment of the peeling force can be controlled by, for example, the type of the composition for the peeling agent layer, the thickness of the peeling agent layer, and the like. The second release film 13 is designed to have a smaller release force than the first release film 12. When the second release film 13 has a release agent layer, the release agent layer is not particularly limited as long as it is made of a material capable of imparting releaseability. For example, the release agent layer of the second release film 13 is obtained by curing a composition for a release agent layer containing silicone, similarly to the release agent layer of the first release film 12.

The composition for the release agent layer of the second release film 13 can be selected from the materials exemplified in the first release film 12 as long as the above relationship between F1 and F2 is satisfied. However, the material exemplified as the heavy release additive is preferably less than or not contained in the first release film 12.

The thickness of the second release film 13 is not particularly limited, but is preferably 10 μm or more and 75 μm or less. The thickness of the second release film is more preferably 18 μm or more, and further preferably 24 μm or more. The thickness of the second release film is more preferably 60 μm or less, and further preferably 45 μm or less. The thickness of the second release film is preferably equal to or less than the thickness of the first release film, and is less than the thickness of the first release film, from the viewpoint of making the release force F2 and the release force 1 F1> F2 described above. More preferred.

The thickness of the second release film means the thickness of the entire second release film. For example, the thickness of the second release film composed of a plurality of layers means the total thickness of all the layers constituting the second release film.

As a method for manufacturing the protective film forming sheet 20, as described in the embodiment, the second release film 13 may be attached to the exposed surface of the protective film forming film 11 laminated with the first release film 12.

When the protective film forming sheet 20 is punched, the die is inserted from the second release film 13 side, and the protective film forming film 11 and the second release film 13 are cut into a predetermined closed shape. It is the same as the said embodiment. As a result, the protective film forming film 11 and the second release film 13 that have been punched are obtained on the first release film 12. The punched protective film forming sheet 20 may be wound into a roll, stored, and transported.

In the scrap raising step, the second release film 13 and the unnecessary portion 17 are simultaneously wound and removed. At this time, the second release film 13 after being punched and completely cut is reattached with a long adhesive tape, so that the second release film 13 can be easily removed. As a result, the protective film forming film 16 cut into a predetermined closed shape remains on the first release film 12.

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

Hereinafter, the invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Preparation of protective film forming sheet)
[First release film (heavy release film)]
<Coating agent containing a composition for a release agent layer>
The following composition raw materials for the release agent layer were prepared.
-Silicone-based mold release agent containing an organopolysiloxane having a vinyl group and an organopolysiloxane having a hydrosilyl group (manufactured by Toray Dow Corning Co., Ltd., BY24-561, solid content 30% by mass)
-Dimethylpolysiloxane (weight average molecular weight: 2000) (manufactured by Shin-Etsu Chemical Co., Ltd., X-62-1387, solid content 100% by mass)
MQ resin with vinyl group as a heavy peeling additive (manufactured by Toray Dow Corning Co., Ltd., SD-7292, solid content 71% by mass)
-Platinum (Pt) catalyst (manufactured by Toray Dow Corning Co., Ltd., SRX-212, solid content 100% by mass)

The above raw materials are added to a mixed solvent of toluene and methyl ethyl ketone (toluene / methyl ethyl ketone = 1/1 (mass ratio)) at the compounding ratio (solid content conversion) shown in Table 1 to adjust the total solid content to 2% by mass. , A coating agent containing a composition for a release agent layer was prepared.

<Making the first release film>
A coating agent containing a composition for a release agent layer is applied to a PET film (manufactured by Mitsubishi Chemical, trade name: Diafoil (registered trademark) T-100, thickness: 50 μm) so that the film thickness after drying becomes 0.15 μm. The release agent layer was formed on the PET film by coating, heating and drying to prepare the first release films (heavy release films) A to C.

<Measurement of surface elastic modulus>
The surface elastic modulus of the peeled surface of the obtained first release film was measured as follows.
A cantilever made of silicon nitride (manufactured by Bruker Corporation, trade name: MLCT, tip radius: 20 nm, resonance frequency: 125 kHz, spring constant: 0.6 N / m) was installed in an atomic force microscope (Made by Bruker Corporation, MultiMode8). The first release film prepared on an atomic force microscope was placed on the cantilever, and the surface of the release agent layer of the prepared first release film was pushed and separated at a pushing amount of 2 nm and a scanning speed of 10 Hz. rice field. This operation was performed at 23 ° C. The force curve curve obtained by this operation was fitted by the JKR theoretical formula, and the surface elastic modulus was calculated. The surface elastic modulus was measured at 4096 points on the surface of the release agent layer of the first release film at 1 μm × 1 μm, these values were averaged and one digit after the decimal point was rounded off to obtain the surface elastic modulus (MPa). The results are shown in Table 1.

[Second release film (light release film)]
Lintec's "SP-PET381130 (thickness 38 μm)" was used.

[Coating agent containing a composition for a protective film forming film]
Each of the following components was mixed at the compounding ratio (in terms of solid content) shown in Table 2 and diluted with methyl ethyl ketone so that the solid content concentration was 50% by mass to prepare a coating agent.

(A) Polymer component (A-1) (meth) acrylic obtained by copolymerizing 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. Acid ester copolymer (weight average molecular weight: 400,000, glass transition temperature: -1 ° C)
(A-2) A (meth) acrylic acid ester 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) Curable component (thermosetting component)
(B-1) Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER828, epoxy equivalent 184 to 194 g / eq)
(B-2) Acrylic rubber fine particle dispersion bisphenol A type liquid epoxy resin (manufactured by Nippon Shokubai Co., Ltd., BPA328, epoxy equivalent 230 g / eq, acrylic rubber content 20 phr)
(B-3) Dicyclopentadiene type epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc., Epicron HP-7200HH, softening point 88 to 98 ° C., epoxy equivalent 255 to 260 g / eq)
(C) Curing agent: dicyandiamide (manufactured by Mitsubishi Chemical Corporation, DICY7)
(D) Curing accelerator: 2-phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Chemicals Corporation, Curesol 2PHZ)
(E) Filler (E-1) Epoxy group-modified spherical silica filler (manufactured by Admatex, SC2050MA, average particle size 0.5 μm)
(E-2) Silica filler (“YC100C-MLA” manufactured by Admatex, average particle diameter 0.1 μm)
(F) Silane coupling agent: γ-glycidoxypropyltrimethoxysilane (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 28 nm)

The prepared protective film-forming film composition is applied to the peel-treated surface of the first release film (any of the above A to C) and dried at 100 ° C. for 2 minutes to form a protective film having a thickness of 20 μm. Was formed. Subsequently, the second release film was attached onto the protective film-forming film to obtain a protective film-forming sheet having a three-layer structure in which the release films were formed on both sides of the protective film-forming film. The pasting conditions were a temperature of 60 ° C., a pressure of 0.4 MPa, and a speed of 1 m / min. Next, the protective film forming sheet was cut to a width of 208 mm, and a roll body having a length of 50 meters was used as a winding body.

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

[Adhesion between protective film forming films]
The protective film-forming film was exposed from the protective film-forming sheet as follows, and the protective film-forming films were attached to each other, and the adhesive force was measured.

<Fixing the protective film forming film on the adhesive tape>
I. The second release film of the protective film forming sheet having a three-layer structure of the second release film / protective film forming film / first release film was peeled off.
II. An adhesive tape manufactured by Lintec Corporation (product name: PET50PL thin: acrylic pressure-sensitive adhesive layer / 50 μm PET base material) is attached to the exposed protective film-forming film at 23 ° C. to obtain “PET base material / acrylic pressure-sensitive adhesive layer / A laminated sample of "protective film forming film / first release film" was prepared.
III. The laminated sample was cut 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. A double-sided tape with a PET film as a core material was attached to the entire surface of a SUS plate (0.5 mm thickness × 70 mm × 150 mm).
II. The second release film of the protective film forming sheet having a three-layer structure of the second release film / protective film forming film / first release film was peeled off.
III. The exposed protective film-forming film was attached to the entire surface of the adhesive surface of the double-sided tape to obtain a laminated sample of "SUS plate / double-sided tape / protective film-forming film / first release film".
IV. The first release film was peeled off to expose the protective film-forming film.

<Measurement of adhesive force>
The first release film was peeled off from the laminate sample of "PET base material / acrylic pressure-sensitive adhesive layer / protective film-forming film / first release film" to expose the protective film-forming film. The laminate of "PET base material / acrylic pressure-sensitive adhesive layer / protective film-forming film" and the laminate of "SUS plate / double-sided tape / protective film-forming film" are laminated so that the protective film-forming films face each other. Then, they were bonded at 23 ° C. using a 2 kg roller.

After leaving it to stand without heating and 2 minutes (± 20 seconds) after application, the adhesive force was measured by the following measuring method.
Using a universal tensile tester (manufactured by Shimadzu Corporation, product name "Autograph AG-IS"), the peeling force is measured at a peeling speed of 300 mm / min, a temperature of 23 ° C, and a peeling angle of 180 ° for a measurement distance of 70 mm. did. The average of the measured values between the first 10 mm and the end of the measurement distance of 50 mm excluding the end 10 mm was defined as "adhesion between protective film-forming films".

[Peeling force F1 of the first release film from the protective film-forming film]
The second release film was peeled off from the obtained protective film forming sheet. A good-adhesive surface of a good-adhesive PET (PET25A-4100, manufactured by Toyobo Co., Ltd.) with a thickness of 25 μm is attached to the surface of the protective film-forming film exposed by peeling by thermal laminating (70 ° C., 1 m / min) to form a laminated body sample. Was produced. A laminated sample was cut into a width of 100 mm to prepare a sample for measurement. The back surface of the first release film of the measurement sample was fixed to a hard support plate with double-sided tape.

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

[Peeling force F2 of the second release film from the protective film forming film]
The obtained protective film forming sheet was cut into a width of 100 mm to prepare a measurement sample. The back surface of the first release film of the measurement sample was fixed to a hard support plate with double-sided tape.

Using a universal tensile tester (manufactured by Shimadzu Corporation, product name "Autograph (registered trademark) AG-IS"), the second release film is peeled off from the measurement sample, and the load at that time is measured in F1. The measurement was performed under the same conditions as above, and the peeling force was F2.

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

[Punching and scraping of protective film forming sheet]
Using Lintec's RAD-3600F / 12 with specifications for 200 mm wafers, the die is inserted from the second release film side of the protective film forming sheet, and the protective film forming film and the second release film are circular (inner diameter 198 mm). Punched out. At this time, the first release film was notched so as not to be completely punched (punching process). Half-cuts with different cutting widths were performed using four types of die with different cutting blade widths. Punching was performed 40 times.

After the punching process, the protective film forming sheet was run between a plurality of rollers. Then, the circularly punched portion was left on the first release film, and the second release film and the unnecessary portion around the circularly punched portion were removed (dust raising step). At this time, the second release film after being punched and completely cut was reattached with a long adhesive tape, and then the second release film was removed.

<Cut width>
The protective film forming sheet after the scrap raising step is cut in the thickness direction so that the cut portion of the first release film is not deformed, the protective film forming sheet is held flat, and the cross section is scanned with a scanning electron microscope (SEM,). It was observed with "VE-9800" manufactured by KEYENCE. The width of the notch remaining in the first release film at the interface between the first release film and the protective film forming film was measured.

The measurement was performed at 6 points (a regular hexagon when connecting the points) at equal intervals on the circumference of one circle by selecting the 20th one out of 40 circular parts. The minimum value among the 6 points was set as the "cut width". One digit after the decimal point was rounded off.

The wider the cut width, the more the protective film-forming films do not adhere to each other, and the scraps can be raised smoothly.

<Evaluation of scrap raising property>
Of the 40 circular portions, the number of sheets of the protective film-forming film in the circular portion that was raised along with the unnecessary portion was counted during the scrap raising step. The smaller the number of sheets raised, the more the protective film-forming films did not adhere to each other, and the more the residue was raised smoothly.

The above results are summarized in Table 3.

From Table 3, it was confirmed that when the adhesive force between the protective film-forming films was 19 N or less, there was no adhesion between the protective film-forming films after the punching process, and the scraps could be raised smoothly. Further, it was found that when the cut width is narrowed as in Example 7, the protective film-forming films tend to adhere to each other after the punching process, and the scrap raising tends to be difficult.

As described above, according to the present invention, there is provided a protective film forming sheet and a method for manufacturing the same, which can sufficiently suppress a scrap raising defect even when the depth of cut at the time of punching is relatively narrow.

10 ... Protective film forming sheet (this embodiment)
11 ... Protective film forming film 12 ... 1st release film 13 ... 2nd release film 14 ... Notch 16 ... Protective film forming film 17 ... Unnecessary part 19 ... Roller 20 ... Protective film forming sheet (other embodiments) )
21 ... Wafer 22 ... Dicing sheet 30 ... Chip 31 with protective film ... Chip 32 ... Protective film 33 ... Convex electrode 50 ... Substrate

Claims (6)

Protective film forming film and
A long sheet having a first release film provided on one surface of the protective film forming film.
A protective film forming sheet having an adhesive force of 19 N / 25 mm or less 2 minutes after the two protective film forming films are attached at 23 ° C. with a load of 2 kgf. The protective film forming sheet according to claim 1, wherein the surface elastic modulus of the surface of the first release film in contact with the protective film forming film is 17 MPa or less. When the protective film forming sheet is viewed in a plan view, a notch is formed in the protective film forming sheet so that a part of the protective film forming sheet has a predetermined closed shape.
The protective film-forming sheet according to claim 1 or 2, wherein the notch penetrates the protective film-forming film and reaches a part of the first release film in the thickness direction of the protective film-forming sheet. The protective film forming sheet according to claim 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. The step of forming a notch so that a part of the protective film forming sheet according to claim 1 or 2 has a predetermined closed shape is provided.
A method for producing a punched protective film-forming sheet in which the cut penetrates the protective film-forming film and reaches a part of the first release film in the thickness direction of the protective film-forming sheet. The method for producing a punched protective film-forming sheet according to claim 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.

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