KR20240137460A - Sheet for forming resin film and workpiece processing method - Google Patents

Abstract

(Task) To prevent identification errors when confirming that peeling has been performed reliably after peeling the middle-surface peeling film (12) from a resin film forming sheet (10) which is a laminated sheet of a middle-surface peeling film (12)/resin film forming film (11)/mirror peeling film (13).
(Solution) The sheet (10) for forming a resin film of the present invention,
A resin film forming film (11) for forming a resin film,
A middle-surface peeling film (12) provided on one side of the above resin film forming film,
Having a hard surface release film (13) provided on the other side of the above resin film forming film,
When the peeling force of the above-mentioned middle-surface peeling film (12) from the above-mentioned resin film forming film (11) is F1 and the peeling force of the above-mentioned hard-surface peeling film (13) from the above-mentioned resin film forming film (11) is F2, the relationship F1 > F2 is satisfied.
The above-mentioned middle-surface peeling film (12) satisfies either one or both of the following: a light transmittance of 555 nm of 80% or less, and a haze of 4% or more.

Description

{SHEET FOR FORMING RESIN FILM AND WORKPIECE PROCESSING METHOD}

The present invention relates to a resin film forming sheet and a method for processing a work using the same. In particular, the present invention relates to a resin film forming sheet having a resin film forming film which is preferably used for producing a protective film for protecting a work such as a semiconductor wafer or a workpiece obtained by processing the work such as a semiconductor chip, or an adhesive film for bonding the workpiece. The present invention also relates to a method for processing a work using the resin film forming sheet.

In recent years, semiconductor devices have been manufactured using a mounting method called flip chip bonding. In this mounting method, when mounting a semiconductor chip having a circuit surface on which convex electrodes such as bumps are formed, the circuit surface side of the semiconductor chip is flipped (face down) and bonded to the chip mounting portion. Therefore, the back side of the semiconductor chip, where the circuit is not formed, is exposed.

For this reason, a hard resin film made of organic material is often formed on the back side of the semiconductor chip to protect the semiconductor chip from impacts such as when returning it. This resin film is called a protective film. The protective film is formed, for example, by attaching a protective film forming film as an example of a resin film forming film to the back side of a semiconductor wafer, and then curing or in a non-cured state.

In addition, semiconductor chips are sometimes bonded to the circuit formation surface of a substrate by a resin film attached to the back surface thereof. A resin film forming film for forming and bonding such a resin film is called a die bonding film. A semiconductor chip is placed on a substrate via the die bonding film by die bonding. Thereafter, if necessary, one or more semiconductor chips are laminated on this semiconductor chip, wire bonding is performed, and the entirety is sealed with resin, thereby producing a semiconductor package.

Patent Document 1 discloses a protective film forming sheet (10) having a three-layer structure in which a protective film forming film (11) for forming a protective film is sandwiched between a first peeling film (12), which is a heavy peeling film, and a second peeling film (13), which is a light peeling film, as shown in FIG. 1. The protective film forming film (11) is laminated so as to be releasable from the first peeling film (12) and the second peeling film (13). The protective film forming sheet of Patent Document 1 satisfies F1 > F2 when the peeling force of the first peeling film (12) from the protective film forming film (11) is F1, and the peeling force of the second peeling film (13) from the protective film forming film (11) is F2. The above-mentioned sheet (10) for forming a protective film is usually long and is wound in a roll shape for storage and transport.

One of the ways of using the sheet (10) for forming a resin film is to peel off a light-surface peeling film (13) having a low peeling force, and to attach the exposed resin film forming film (11) to a workpiece. Thereafter, a process of cutting off unnecessary parts of the middle-surface peeling film (12) and the resin film forming film (11) according to the shape of the outer circumference of the workpiece may be performed. Thereafter, the middle-surface peeling film (12) is peeled off from the resin film forming film (11), and the resin film forming film (11) is cured by a predetermined means to form a protective film, thereby obtaining a workpiece with a protective film attached. The workpiece with the protective film attached is diced to be separated into pieces, and a workpiece separated into pieces having a protective film on the back surface is obtained. In addition, the curing of the resin film forming film (11) may be performed after dicing. For example, when the resin film is used as an adhesive film, it is diced in an uncured state, and the resin film is cured as necessary at the time of bonding.

Japanese Patent Publication No. 2022-32571

In the process of peeling the above-mentioned middle-surface peeling film (12) from the resin film forming film (11), peeling of the middle-surface peeling film (12) is confirmed by a sensor or by visual inspection, but there were cases where identification errors occurred at this time. That is, there were cases where the middle-surface peeling film (12) was judged to be peeled even though it was not peeled and was transferred to the next process.

The inventor of the present invention has conducted careful examination to prevent such identification errors and has completed the present invention.

The aspect of the present invention that solves these problems is as follows.

(1) A resin film forming film for forming a resin film,

A middle-side peeling film provided on one side of the above resin film forming film,

Having a hard-surface peeling film provided on the other side of the above resin film forming film,

When the peeling force of the above-mentioned middle-surface peeling film from the above-mentioned resin film forming film is F1, and the peeling force of the above-mentioned hard-surface peeling film from the above-mentioned resin film forming film is F2, the relationship F1 > F2 is satisfied,

The above-mentioned middle-surface peeling film is a sheet for forming a resin film, which satisfies either one or both of a light transmittance of 555 nm of 80% or less and a haze of 4% or more.

(2) A sheet for forming a resin film as described in (1), wherein at least one side of the above-mentioned middle-surface peeling film is roughened.

(3) The above-mentioned middle-surface peeling film is a colored resin film forming sheet described in (1).

(4) The resin film forming sheet described in (1), wherein the average value of the light reflectance at 400 to 800 nm of the contact surface of the resin film forming film with the middle-surface peeling film is 40% or less.

(5) The resin film forming sheet described in (1), wherein the arithmetic mean height Sa of the contact surface of the above-mentioned middle-surface peeling film with the resin film forming film is less than 0.03 ㎛.

(6) A process of peeling off the hard surface peeling film of the resin film forming sheet described in any one of (1) to (5) above and attaching the exposed resin film forming film to a workpiece.

A process for peeling a middle-surface peeling film from a resin film forming film attached to a work, and

A method for processing a workpiece, comprising a process for confirming the peeling of a middle-surface peeling film.

According to the present invention, confirmation of peeling of a middle-surface peeling film (12) can be performed with high precision.

Fig. 1 is a cross-sectional schematic diagram of a sheet for forming a resin film according to the present embodiment.

First, we explain the main terms used in this specification.

The work is a plate-shaped body to which the resin film forming film according to the present embodiment is attached and processed. Examples of the work include a wafer and a panel. Specifically, a semiconductor wafer and a semiconductor panel can be mentioned. Examples of the processed product of the work include a chip obtained by dividing a wafer into pieces. Specifically, a semiconductor chip obtained by dividing a semiconductor wafer is exemplified. In this case, the resin film is formed on the back side of the wafer and the chip.

The "surface" of a work such as a wafer refers to the surface on which circuits and convex electrodes such as bumps are formed, and the "back surface" refers to the surface on which circuits, electrodes (e.g. convex electrodes such as bumps), etc. are not formed.

The resin film forming film is transferred to a work and functions as a film that forms a protective film or adhesive film.

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

A peeling film is a film that supports a resin film forming film so that it can be peeled. The film does not have a limited thickness, and is used as a concept including a sheet. A middle-surface peeling film and a mirror-surface peeling film are distinguished by the peeling force from the resin film forming film. When the peeling force from the resin film forming film of the middle-surface peeling film is F1, and the peeling force from the resin film forming film of the mirror-surface peeling film is F2, the relationship F1 > F2 is satisfied.

In the description of the composition for a resin film forming film and the composition for a release agent layer, the mass ratio is based on the effective ingredient (solid content), and unless otherwise specified, the solvent is not included.

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

(1. Resin film formation film)

As shown in Fig. 1, the resin film forming sheet (10) according to the present embodiment has a resin film forming film (11) (more specifically, a protective film forming film (11)), a middle-surface release film (12) provided on one side of the resin film forming film (11), and a hard-surface release film (13) provided on the other side. This resin film forming sheet is usually wound in a roll shape as a long sheet.

Examples of the resin film include a protective film for protecting a work or work reforming material, and an adhesive film for adhering a work reforming material to a substrate, etc.

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

By superimposing a workpiece onto a curable resin film forming film and then curing the resin film forming film, the resin film can be firmly adhered to the workpiece, thereby forming a durable protective film.

When the resin film forming film (11) does not contain a curable component and is used as a protective film in a non-cured state, the resin film forming film according to the present embodiment is formed into a protective film at the time when it is attached to the work. In other words, the resin film may be the same as the resin film forming film.

If high protective performance is not required, there is no need to cure the resin film forming film, so the resin film forming film may be non-curable.

In this embodiment, the resin film forming film is preferably curable. Therefore, the resin film is preferably a cured product. Examples of the cured product include a thermosetting product and an energy ray cured product. In this embodiment, it is more preferable that the resin film is a thermosetting product.

In addition, it is preferable that the resin film forming film has adhesiveness at room temperature (23°C) or exhibits adhesiveness upon heating. Accordingly, when overlapping a workpiece on the resin film forming film, the two can be bonded together. Therefore, positioning can be reliably determined before curing the resin film forming film.

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

In this embodiment, it is preferable that the resin film forming film is a single layer (monolayer). If the resin film forming film is composed of multiple layers, there is a risk that delamination occurs between layers due to differences in thermal elasticity between layers in a process where temperature changes occur (during reflow processing or when using the device), but if it is a single layer, that risk can be reduced.

The thickness of the resin film forming film is not particularly limited, but is preferably 100 µm or less, more preferably 70 µm or less, still more preferably 50 µm or less, and particularly preferably 40 µm or less. Furthermore, it is preferably 5 µm or more, more preferably 10 µm or more, still more preferably 15 µm or more, and particularly preferably 20 µm or more. When the thickness of the resin film forming film is within the above range, the workability when cutting the resin film forming sheet to fit the shape of the workpiece is excellent, and the protective performance of the obtained resin film is improved.

In addition, the thickness of the resin film forming film means the thickness of the entire resin film forming film. For example, the thickness of a resin film forming film composed of multiple layers means the thickness of the sum of all layers constituting the resin film forming film.

Hereinafter, a protective film formed by a protective film forming film according to the present embodiment is described. An example of a protective film-attached work-piece, a protective film-attached chip, has a protective film formed on the back side of the chip (a surface on which a circuit is not formed). A circuit and an electrode are formed on the surface side of the chip, and the electrode is formed so as to be electrically connected to the circuit. The protective film-attached chip is arranged so that the surface on which the electrode is formed faces the chip-mounting substrate. Thereafter, the chip is mounted by electrically and mechanically joining the substrate with the electrode through a predetermined heat treatment (reflow treatment). Examples of the electrode include a bump, a pillar electrode, and the like.

(1.1 Peeling characteristics of resin film formation film)

In the present embodiment, when the peeling force of the middle-surface peeling film (12) from the resin film forming film (11) is F1, and the peeling force of the mirror-surface peeling film from the resin film forming film is F2, the relationship F1 > F2 is satisfied, preferably F1 > 1.2 × F2, more preferably F1 > 1.5 × F2, and even more preferably F1 > 2 × F2. When the peeling force F1 and the peeling force F2 satisfy the above relationship, the removal of the mirror-surface peeling film becomes easy, the exposure of the resin film forming film can be performed smoothly, and the work can be reliably attached to the resin film forming film. The upper limit of the peeling force F1 is not particularly limited, but in relation to the peeling force F2, it preferably satisfies the relationship F1 < 10 × F2, more preferably F1 < 7 × F2, more preferably F1 < 5 × F2, and especially preferably F1 < 3.5 × F2. The peeling force F1 and the peeling force F2 satisfy the above relationship. In addition, F2 is preferably 30 mN/100 mm or more, more preferably 40 mN/100 mm or more, and even more preferably 50 mN/100 mm or more.

In addition, the peeling force F1 is preferably 50 mN/100 mm or more, more preferably 70 mN/100 mm or more, still 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, the resin film forming film (11) and the middle-surface peeling film (12) can be suppressed from being unintentionally peeled off.

(1.2 Composition for resin film forming film)

If the resin film forming film has the above properties, the composition of the resin film forming film is not particularly limited. In the present embodiment, the composition constituting the resin film forming film (composition for the resin film forming film) is preferably a resin composition containing at least a polymer component (A), a curable component (B), and a filler (E). The polymer component is a component that can be considered to have been formed by a polymerization reaction of a polymerizable compound. In addition, the curable component is a component that can undergo a curing (polymerization) reaction. In addition, in the present invention, the polymerization reaction also includes a polycondensation reaction.

In addition, there are cases where a component included in a polymer component also corresponds to a curable component. In the present embodiment, when a composition for a resin film forming film contains components corresponding to both the polymer component and the curable component, the composition for a resin film forming film is considered to contain both the polymer component and the curable component.

(1.2.1 Polymer Components)

The polymer component (A) imparts film-forming properties (film-forming properties) to the resin film-forming film, while providing an appropriate tack, thereby ensuring uniform adhesion of the resin 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 million. If the weight average molecular weight is too low, the peeling force of the peeling film tends to increase. On the other hand, if the weight average molecular weight is too high, the compatibility with other components deteriorates, resulting in the impediment of uniform film formation. Examples of such polymer components include acrylic resins, urethane resins, phenoxy resins, silicone resins, and saturated polyester resins, and acrylic resins are particularly preferably used.

In addition, in this specification, unless otherwise specified, the "weight average molecular weight" is a polystyrene conversion value measured by the gel permeation chromatography (GPC) method. The measurement by this method is performed, for example, using a high-speed GPC device "HLC-8120GPC" manufactured by TOSOH CORPORATION, in which high-speed columns "TSK gurd column H _XL -H", "TSK Gel GMH _XL ", and "TSK Gel G2000 H _XL " (all manufactured by TOSOH CORPORATION) are connected in this order, under the conditions of a column temperature of 40°C and a feed speed of 1.0 mL/min, and a differential refractometer as a detector.

As the acrylic resin, for example, 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 can be mentioned. Here, as the (meth)acrylic acid ester monomer, a (meth)acrylic acid alkyl ester having an alkyl group of 1 to 18 carbon atoms can be mentioned, and specific examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and the like. In addition, as the (meth)acrylic acid derivative, for example, (meth)acrylic acid, glycidyl (meth)acrylate, hydroxyethyl (meth)acrylate, and the like can be mentioned.

In this embodiment, it is preferable to introduce a glycidyl group into the acrylic resin using glycidyl methacrylate or the like. The compatibility of the acrylic resin into which the glycidyl group has been introduced and the epoxy resin as a thermosetting component described later is improved, and the glass transition temperature (Tg) of the resin film forming film after curing is increased, thereby improving the heat resistance. Furthermore, in this embodiment, it is preferable to introduce a hydroxyl group into the acrylic resin using hydroxyethyl acrylate or the like in order to control the adhesion to the work or the adhesive properties.

The glass transition temperature of the acrylic resin is preferably -70°C to 40°C, more preferably -35°C to 35°C, even more preferably -20°C to 30°C, even more preferably -10°C to 25°C, and particularly preferably -5°C to 20°C. By setting the glass transition temperature of the acrylic resin within the above range, the fluidity of the resin film-forming film and the resin film during heating is suppressed, so that a smooth resin film is easily obtained. If the glass transition temperature is too low, the peeling force of the release film tends to increase. If the glass transition temperature is too high, the compatibility with other components deteriorates, and as a result, uniform film formation is hindered, and further, the peeling force F2 of the mirror-like release film tends to be excessively reduced.

When an acrylic resin has m kinds of constituent units (m is an integer greater than or equal to 2), the glass transition temperature of the acrylic resin can be calculated as follows. That is, when m kinds of monomers that induce constituent units in an acrylic resin are sequentially assigned a non-overlapping number from 1 to m and named "monomer m", the glass transition temperature (Tg) of the acrylic resin can be calculated using Fox's equation shown below.

[Number 1]

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

[Number 2]

(In the equation, m and Wk are as above.)

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

When the total weight of the composition for a resin 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, still more preferably 10 to 60 parts by mass, still 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 peeling strength of the peeling film is limited to an appropriate range, so that material design of the composition for a resin film forming film becomes easy.

(1.2.2 Thermosetting components)

The curable component (B) cures the resin film forming film to form a hard resin 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 resin film forming film according to the present embodiment has a reduced light transmittance because it contains a filler and a colorant, etc., which will be described later. Therefore, for example, when the thickness of the resin film forming film becomes thick, energy ray curing tends to become insufficient.

Meanwhile, since the thermosetting resin film forming film is sufficiently cured by heating even when its thickness is increased, it can form a resin film with high protective performance. In addition, by using a normal heating means such as a heating oven, a plurality of resin film forming films can be heated at once and heat-cured.

Therefore, in the present embodiment, the curable component is preferably thermosetting. That is, the resin film forming film according to the present embodiment is preferably thermosetting.

Whether or not the resin film forming film is thermosetting can be judged as follows. First, the resin film forming film at room temperature (23°C) is heated until the temperature exceeds room temperature, and then cooled until it reaches room temperature, thereby obtaining a resin film forming film after heating and cooling. Next, when the hardness of the resin film forming film after heating and cooling is compared with the hardness of the resin film forming film before heating at the same temperature, if the resin film forming film after heating and cooling is harder, the resin film forming film is judged to be thermosetting.

As the thermosetting component, for example, epoxy resin, thermosetting polyimide resin, unsaturated polyester resin, and mixtures thereof are preferably used. In addition, the thermosetting polyimide resin is a general term for low molecular weight, low viscosity monomer or precursor polymer that forms a polyimide resin by thermosetting. Non-limiting specific examples of the thermosetting polyimide resin are described in, for example, the Journal of the Textile Society, "Textile and Industry", Vol. 50, No. 3 (1994), P106-P118.

As a thermosetting component, an epoxy resin has the property of forming a three-dimensional network when heated, thereby forming a strong film. As such an epoxy resin, various known epoxy resins are used. In the present embodiment, the molecular weight (molecular weight) of the epoxy resin is preferably 300 or more and less than 50,000, 300 or more and less than 10,000, 300 or more and less than 5,000, or 300 or more and less than 3,000. In addition, the epoxy equivalent of the epoxy resin is preferably 50 to 5,000 g/eq, more preferably 100 to 2,000 g/eq, and still more preferably 150 to 1,000 g/eq.

Specific examples of such epoxy resins include glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenyl novolac, and cresol novolac; glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; glycidyl ethers of carboxylic acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; glycidyl-type or alkylglycidyl-type epoxy resins in which active hydrogen bonded to a nitrogen atom of aniline isocyanurate is substituted with a glycidyl group; Examples of so-called alicyclic epoxides in which epoxy is introduced by oxidizing the carbon-carbon double bond in the molecule, such as vinylcyclohexane diepoxide, 3,4-epoxycyclohexylmethyl-3,4-dicyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, may be mentioned. In addition, epoxy resins having a biphenyl skeleton, a dicyclohexadiene skeleton, a naphthalene skeleton, and the like can also be used.

Among these epoxy resins, when using an epoxy resin that is liquid at room temperature (23°C), when the total weight of the composition for a resin film forming film is 100 parts by mass, the weight of the epoxy resin that is liquid at room temperature is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, and even more preferably 1 to 11 parts by mass. When such a liquid epoxy resin is included in a large amount, the peeling strength of the peeling film from the resin film forming film tends to increase.

As epoxy resins that are liquid at room temperature (23°C) (liquid epoxy resins), examples thereof include glycidyl ethers of bisphenol A (bisphenol A type epoxy resin), glycidyl ethers of bisphenol F (bisphenol F type epoxy resin), phenol novolac type epoxy resins, naphthalene type epoxy resins, cyclohexanedimethanol type epoxy resins, and glycidylamine type epoxy resins, among which those having small molecular weights can be mentioned.

When a thermosetting component is used as the curable component (B), it is preferable to use a curing agent (C) together as an auxiliary agent. As the curing agent for the epoxy resin, a heat-activated latent epoxy resin curing agent is preferable. A "heat-activated 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) and is activated by heating at a certain temperature or higher and reacts with the epoxy resin. Methods for activating a heat-activated latent epoxy resin curing agent include a method of generating an active species (anion, cation) through a chemical reaction by heating; a method of stably dispersing the curing agent in the vicinity of room temperature in the epoxy resin and being compatible and dissolving with the epoxy resin at high temperature to initiate a curing reaction; a method of using a molecular sieve-encapsulated type curing agent that is eluted at high temperature to initiate a curing reaction; and a method using microcapsules.

Among the methods exemplified, a method in which the compound is stably dispersed in an epoxy resin at around room temperature and is compatible with and dissolves in the epoxy resin at high temperatures and initiates a curing reaction is preferable.

Specific examples of the thermally activated latent epoxy resin curing agent include various onium salts, dibasic acid dihydrazide compounds, dicyandiamide, amine adduct curing agents, high-melting-point active hydrogen compounds such as imidazole compounds, etc. These thermally activated latent epoxy resin curing agents can be used singly or in combination of two or more. In the present embodiment, dicyandiamide is particularly preferred.

In addition, as a curing agent for the epoxy resin, a phenol resin is also preferable. As the phenol resin, a condensate of a phenol such as an alkylphenol, a polyhydric phenol, a naphthol, and an aldehyde, etc., is used without particular limitation. Specifically, a phenol novolac resin, an o-cresol novolac resin, a p-cresol novolac resin, a t-butylphenol novolac resin, a dicyclopentadiene cresol resin, a polyparavinylphenol resin, a bisphenol A type novolac resin, or a modified product thereof, etc., is used.

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

The content of the hardener (C) is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, even more preferably 0.2 to 15 parts by mass, and particularly preferably 0.3 to 10 parts by mass, per 100 parts by mass of the epoxy resin. By setting the content of the hardener (C) within the above range, the network structure of the resin film becomes dense, so that the performance of protecting the work as the resin film can be easily obtained.

When using dicyandiamide as a curing agent (C), it is preferable to further use a curing accelerator (D). As the curing accelerator, for example, imidazoles (imidazoles in which one or more hydrogen atoms are substituted with a group other than a hydrogen atom) such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole are preferable. Among these, 2-phenyl-4,5-dihydroxymethylimidazole 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, even more preferably 0.2 to 15 parts by mass, and particularly preferably 0.3 to 10 parts by mass, per 100 parts by mass of the epoxy resin. By setting the content of the curing accelerator (D) within the above range, the network structure of the resin film becomes dense, so that the performance of protecting the work as the resin film can be easily obtained.

When the total weight of the composition for forming a resin film is 100 parts by mass, the total content of the thermosetting component and the curing agent is preferably 3 to 80 parts by mass, more preferably 5 to 60 parts by mass, still more preferably 7 to 50 parts by mass, still 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 mixed in this ratio, an appropriate tack is exhibited before curing, and the bonding work can be stably performed. Furthermore, after curing, the performance of protecting the work as a resin film can be easily obtained.

When a low molecular weight compound is used as a thermosetting component and a curing agent, the tackiness of the resin film forming film increases, and the peeling strength of the peeling film may be enhanced. Therefore, it is preferable to select the type and blending amount of the thermosetting component and the curing agent so as to control the tackiness to an appropriate value within the above range.

(1.2.3 Energy ray curable component)

When the curable component (B) is an energy ray curable component, the energy ray curable component is preferably uncured and preferably has adhesiveness, and is more preferably uncured and also has adhesiveness.

The energy ray curable component is a component that is cured by irradiation with energy rays, and is also a component that provides film-forming properties such as film-forming properties and flexibility to the resin film.

As the energy ray curable component, a compound having an energy ray curable group is preferable. Known compounds can be cited as such compounds.

When a low molecular weight compound is used as an energy ray curable component, the tackiness of the resin film forming film increases, and the peeling strength of the peeling film may be enhanced. Therefore, it is preferable to select the type and blending amount of the energy ray curable component so as to control the tackiness to an appropriate value.

(1.2.4 Filler)

Since the resin film forming film contains the filler (E), the resin film formed from the resin film forming film can easily have its thermal expansion coefficient adjusted, and by making this thermal expansion coefficient close to the thermal expansion coefficient of the work, the adhesion reliability of the package obtained using the resin film forming film is further improved. In addition, since the resin film forming film contains the filler (E), a hard resin film is obtained, and furthermore, the moisture absorption rate of the resin film can be reduced, so that the adhesion reliability of the package is further improved.

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

Preferred inorganic fillers include, for example, powders of silica, alumina, talc, calcium carbonate, bengala, silicon carbide, boron nitride, etc.; beads obtained by spheroidizing these inorganic fillers; surface-modified products of these inorganic fillers; single-crystal fibers of these inorganic fillers; glass fibers, etc. Among these, silica and surface-modified silica are 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 ㎛, more preferably 0.05 to 5 ㎛, and particularly preferably 0.10 to 3 ㎛.

By setting the average particle size of the filler to the above value, the handling properties of the composition for a resin film forming film are improved. Therefore, the quality of the composition for a resin film forming film and the resin film forming film are likely to be stable.

In addition, in this specification, unless otherwise specified, the “average particle diameter” means the particle diameter (D50) at 50% of the accumulated value in a particle size distribution curve obtained by laser diffraction scattering method.

When the total weight of the composition for forming a resin film is 100 parts by mass, the upper limit of the content of the filler is preferably less than 80 parts by mass, more preferably less than 70 parts by mass, more preferably less than 60 parts by mass, and particularly preferably less than 55 parts by mass, and the lower limit is preferably 15 parts by mass or more, more preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and particularly preferably 45 parts by mass or more.

By setting the content of the filler to the above value, it is easy to control the peeling strength of the peeling film within an appropriate range. If the content of the filler is too small, the tackiness of the resin film forming film increases, and the peeling strength of the peeling film increases excessively. On the other hand, if the mixing amount of the filler is too large, the shape retention of the resin film forming film may be reduced.

In addition, the resin film forming film may contain two or more types of fillers. That is, the filler (E) may be a mixture of two or more types of fillers. "Contains two or more types of fillers" means that it may contain two or more types of fillers of different materials, and it may contain two or more types of fillers with different average particle sizes.

In addition, whether the resin film or resin film-forming film contains two or more types of fillers having different average particle diameters can be confirmed by observing the cross-section of the resin film or resin film-forming film.

(1.2.5 Coupling agent)

It is preferable that the resin film forming film contains a coupling agent (F). By containing a coupling agent, after curing of the resin film forming film, the adhesiveness between the resin film and the work can be improved without damaging the heat resistance of the resin film, and the water resistance (moisture resistance) can be improved. As the coupling agent, a silane coupling agent is preferable from the viewpoint of its versatility and cost merit.

As the silane coupling agent, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-(methacryloxypropyl)trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, Examples include vinyltriacetoxysilane and imidazole silane. These can be used singly or in combination of two or more.

Preferred examples of the silane coupling agent include oligomeric silane coupling agents having multiple alkoxysilyl groups per molecule. The oligomeric silane coupling agent is preferable in that it is difficult to volatilize and is effective in improving durability because it has multiple alkoxysilyl groups per molecule. Examples of the oligomeric silane coupling agent include epoxy group-containing oligomeric silane coupling agents such as "X-41-1053", "X-41-1059A", "X-41-1056", and "X-40-2651" (all manufactured by Shin-Etsu Chemical Co., Ltd.); mercapto group-containing oligomeric silane coupling agents such as "X-41-1818", "X-41-1810", and "X-41-1805" (all manufactured by Shin-Etsu Chemical Co., Ltd.).

When the total weight of the composition for forming a resin film is 100 parts by mass, the content of the coupling agent is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, even more preferably 0.2 to 5 parts by mass, and particularly preferably 0.3 to 3 parts by mass.

(1.2.6 Colorant)

It is preferable that the resin film forming film contains a coloring agent (G). Accordingly, since the back surface of the workpiece fragmentation material such as a chip is concealed, various electromagnetic waves generated within the electronic device can be blocked, thereby reducing malfunction of the workpiece fragmentation material such as a chip. In addition, if residual adhesion of the resin film forming film occurs on a roller such as a tension roller or a cutting blade within the resin film forming film attachment device, it can be immediately detected with the naked eye. In addition, it is easy to control the average value of the light reflectance at 400 to 800 nm of the contact surface with the middle-surface release film (12) of the resin film forming film (11) described later within a desired range.

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

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

The blending amount of the colorant (particularly carbon black) in the resin film forming film varies depending on the thickness of the resin film forming film. For example, when the thickness of the resin film forming film is 20 µm, the content of the colorant when the total weight of the composition for the resin film forming film is 100 parts by mass is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 4 parts by mass.

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

(1.2.7 Other additives)

The composition for a resin film forming film may contain other additives, such as a photopolymerization initiator, a crosslinking agent, a plasticizer, an antistatic agent, an antioxidant, a gettering agent, a tackifier, a release agent, etc., within a range that does not impair the effects of the present invention.

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

(1.2.8 Control of peeling force and adhesive force in resin film forming film)

As described above, in the present embodiment, the peeling force F1 of the middle-surface peeling film (12) from the resin film forming film (11) and the peeling force F2 of the mirror-surface peeling film (13) from the resin film forming film (11) satisfy the relationship F1 > F2. As described above, such peeling characteristics can be controlled by the type and mixing amount of each component constituting the resin film forming film, the type of the peeling agent of the middle-surface peeling film (12) and the mirror-surface peeling film (13), and the manufacturing process of the resin film forming sheet.

When the weight average molecular weight of the polymer component (A) is low, the peel strength tends to increase. When the glass transition temperature of the polymer component (A) is low, the peel strength tends to increase. In addition, 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 peel strength tends to increase. When the amount of the filler (E) blended is large, the peel strength tends to decrease.

By partially curing the resin film forming film, the peeling strength can also be controlled. For example, by partially curing the curable component (B), the peeling strength can be reduced.

In addition, the peeling force F1 and F2 can be controlled by the peeling treatment of the middle-surface peeling film (12) and the hard-surface peeling film (13). In addition, they can be controlled by the manufacturing process of the sheet for forming the resin film, etc. This will be described later.

(2. Sheet for forming resin film)

Before use, the resin film forming film is stored in the form of a three-layer resin film forming sheet (10) in which the resin film forming film (11) is sandwiched between two peeling films (a middle-surface peeling film (12) and a hard-surface peeling film (13)), as shown in Fig. 1. The peeling films are peeled off when the resin film forming film is used. The resin film forming sheet is usually long and is wound up in a roll shape for storage and transport.

The middle-surface release film and the mirror-surface release film may be composed of a substrate of one layer (single layer) or two or more layers, and from the viewpoint of controlling the release property, the surface of the substrate may be subjected to a release treatment. That is, the surface of the substrate may be modified, and a layer of a material different from that of the substrate may be formed on the surface of the substrate. In the present embodiment, the middle-surface release film and the mirror-surface release film preferably have a substrate and a release agent layer. By having a release agent layer, it is easy to control the physical properties of the surface on which the release agent layer is formed in the middle-surface release film and the mirror-surface release film. In the present embodiment, a coating agent including a release agent layer composition described later is applied to one surface of the substrate, and then the coating film is dried and cured to form a release agent layer. Thereby, the middle-surface release film and the mirror-surface release film are obtained.

(2.1 Mid-surface peeling film (12))

The thickness of the mid-surface peeling film (12) is not particularly limited, but is preferably 30 to 100 µm, more preferably 40 to 80 µm, and even more preferably 45 to 70 µm, and is preferably thicker than the thickness of the later hard-surface peeling film (13).

Since the thickness of the middle-surface peeling film (12) is within the above range, the workability when cutting the sheet for forming the resin film to fit the shape of the work is excellent.

In addition, the thickness of the middle-surface peeling film (12) means the thickness of the entire middle-surface peeling film. For example, the thickness of a middle-surface peeling film composed of multiple layers means the total thickness of all layers constituting the middle-surface peeling film.

As the substrate of the middle-surface peeling film (12), resin films and paper, etc. can be mentioned. As the resin of the resin film, polyethylene terephthalate, polyethylene, polypropylene, polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polybutylene terephthalate, polyurethane, ethylene-vinyl acetate copolymer, ionomer resin, ethylene (meth)acrylic acid copolymer, polystyrene, polycarbonate, fluororesin, low-density polyethylene, linear low-density polyethylene, and triacetyl cellulose can be mentioned. As the paper, high-quality paper, coated paper, glassine paper, and laminated paper can be mentioned. One type of these may be used alone, or two or more types may be used in combination. Among these, polyethylene terephthalate film is preferable from the viewpoint of being inexpensive and having rigidity.

At least one side (the side laminated with the resin film forming film (11)) of the middle-surface release film (12) may be subjected to release treatment using a composition for a release agent layer. 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 middle-side release film (12) is easily obtained by performing a release treatment on one side of the above-described substrate. The release layer composition used for this release treatment is preferably an alkyd-based release agent, a silicone-based release agent, a fluorine-based release agent, an unsaturated polyester-based release agent, a polyolefin-based release agent, or a wax-based release agent, and among these, a silicone-based release agent is preferable, and particularly, one containing a silicone-based release agent and a middle-side release additive is preferable.

As a silicone release agent, a silicone release agent that contains silicone having dimethylpolysiloxane as its basic skeleton can be used.

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

Specific examples of addition-reactive silicones include organopolysiloxanes having two or more alkenyl groups having 2 to 10 carbon atoms, such as vinyl groups, allyl groups, propenyl groups, and hexenyl groups, at the terminal and/or side chains of the molecule.

When the total weight of the composition for a peeling layer (excluding the catalyst described later) is 100 parts by mass, the content of silicone made of dimethylpolysiloxane is preferably less than 100 parts by mass, more preferably less than 90 parts by mass, even more preferably less than 80 parts by mass, and particularly preferably less than 70 parts by mass.

When using such additional reactive silicone, it is desirable to use a crosslinking agent and a catalyst together.

As a crosslinking agent, an example may be an organopolysiloxane having hydrogen atoms bonded to at least two silicon atoms in one molecule.

Specific examples of the crosslinking agent include a dimethylhydrogensiloxy group-terminated dimethylsiloxane-methylhydrogensiloxane copolymer, a trimethylsiloxy group-terminated dimethylsiloxane-methylhydrogensiloxane copolymer, a trimethylsiloxy group-terminated methylhydrogenpolysiloxane, and poly(hydrogensilsesquioxane).

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

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

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

The heavy-release additive is used to increase the peeling force F1 of the heavy-release film (12) from the resin film forming film (11). Examples of the heavy-release additive include organosilanes such as silicone resin and silane coupling agents, but among these, it is preferable to use silicone resin.

As the silicone resin, for example, it is preferable to use an MQ resin including 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 ]. In addition, three R in the M unit each independently represent a hydrogen atom, a hydroxyl group, or an organic group. From the viewpoint of making it easy to suppress silicone migration, at least one of the three R in the M unit is preferably a hydroxyl group or a vinyl group, and is more preferably a vinyl group.

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

From the viewpoint of improving the applicability to the substrate by adjusting the viscosity, the composition for the release layer is preferably used as a coating agent containing the various effective ingredients described above and a dilution solvent. In this specification, the "effective ingredient" refers to a component excluding the dilution solvent among the components contained in the coating agent containing the target composition.

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

The concentration of the effective ingredient (solid content) of the coating agent including the composition for the peeling layer is preferably 0.3 to 10 mass%, more preferably 0.5 to 5 mass%, and even more preferably 0.5 to 3 mass%.

The composition for the release layer may contain additives generally used in release layers, as long as the effects of the present invention are not impaired. Such additives include pigments, dyes, and dispersants.

(2.2 Hard surface peeling film (13))

The thickness of the hard-surface peeling film (13) is not particularly limited, but from the viewpoint of facilitating peeling, it is preferably less than the thickness of the middle-surface peeling film (12), and more preferably thinner than the middle-surface peeling film (12). Accordingly, the thickness of the hard-surface peeling film (13) is preferably 10 to 75 µm, more preferably 18 to 60 µm, and even more preferably 24 to 45 µm.

The substrate used in the hard-surface release film (13) is the same as that of the above-mentioned middle-surface release film (12) in terms of material. The composition for the release agent layer of the hard-surface release film (13) can be selected from the materials exemplified in the middle-surface release film (12) as long as it satisfies the relationships of F1 and F2 described above. However, when controlling the release force by the composition of the composition for the release agent layer, it is preferable that the material exemplified as the middle-surface release additive is contained in a smaller amount than that in the middle-surface release film (12), or is not contained at all.

In addition, since the peeling force can be suppressed to a low level by adding silicone oil to the composition for the peeling agent layer, silicone oil can be used to adjust the peeling force.

(2.3 Control of peeling force in peeling film)

The peeling power F1 and F2 are controlled by the following various factors in addition to the composition of the above-mentioned resin film formation film.

·Type of resin material that constitutes the main component of the composition for the release layer (silicon-based, fluorine-based, long-chain alkyl-based, etc.)

·Molecular weight of the resin material forming the main component of the composition for the release layer

· Crosslinking density of the composition for the release layer (this crosslinking density is also affected by the type of crosslinking agent, the content before the crosslinking reaction, the density of functional groups that react with the crosslinking agent, etc.)

·Additive components contained in the composition for the release layer (specifically, low molecular weight substances that are not crosslinked and/or difficult to crosslink are exemplified)

·Thickness of the peeling layer

· Surface roughness of the bonding surface with the resin film forming film of the release layer

·Thickness of the resin film

·Temperature at the time of bonding the peeling film and the resin film forming film

·Pressure during bonding of the peeling film and the resin film forming film

·Roller speed when bonding the peeling film and the resin film forming film

If the thickness of the base resin film is thin, it can be peeled with a small peeling force, and if it is thick, the peeling force tends to increase. If one side of the peeling film is roughened and a resin film forming film is formed on the roughened side, the peeling force of the peeling film tends to increase, that is, it becomes a double-sided peeling film. In addition, if a coating agent containing a composition for a resin film forming film described later is applied to a first peeling film, dried if necessary, and then a second peeling film is laminated, the peeling force of the first peeling film tends to increase and the peeling force of the second peeling film tends to decrease.

If the bonding surface of the release film with the resin film forming film is smoothed, a middle-surface release film and a mirror-surface release film can be obtained by the prescription of the release agent layer composition relatively unaffected by the manufacturing process as described above. When the peeling force of the middle-surface release film is controlled by the prescription of the release agent layer composition, the arithmetic mean height Sa of the contact surface of the middle-surface release film with the resin film forming film (the peeling-treated surface of the middle-surface release film) is preferably 1 µm or less, more preferably 0.2 µm or less, still more preferably 0.1 µm or less, and particularly preferably less than 0.03 µm. The arithmetic mean height Sa of the peeling-treated surface of the middle-surface release film (12) can be controlled by, for example, the film forming method of the resin film as the substrate (specifically, the stretching method or the temperature and surface roughness of the cooling roll), surface processing of the substrate after film forming, the thickness of the release agent layer, etc.

Arithmetic mean height of the surface is one of the surface roughness parameters specified in ISO25178, and is the average of the absolute values of the peak height and valley depth on the measurement surface. In this specification, the arithmetic mean height Sa is the surface roughness obtained by using a 1.0 mm × 1.0 mm square area as the measurement surface. In addition, the method for measuring the arithmetic mean height Sa in the present invention is described in detail in the examples described below.

(2.4 Identification control of the mid-surface peeling film)

The present invention aims to improve the accuracy of confirmation of peeling of a middle-surface peeling film (12) in processing a workpiece such as a semiconductor wafer using a sheet for forming a resin film.

To achieve this purpose, the present invention is characterized in that the 555 nm light transmittance of the middle-surface peeling film (12) is 80% or less, or the haze is 4% or more. In addition, the middle-surface peeling film may satisfy the above light transmittance and haze at the same time. When the middle-surface peeling film (12) satisfies the above light transmittance and/or the above haze, the identification of the middle-surface peeling film (12) increases, and it is possible to reliably determine by a sensor or the naked eye whether peeling of the middle-surface peeling film (12) has been performed, so that the processing of the work can be performed smoothly.

From this point of view, the 555 nm light transmittance of the middle-surface release film (12) is preferably 70% or less, more preferably 60% or less, and particularly preferably 50% or less. By being less than or equal to the upper limit, the identification can be further improved. The lower limit of the light transmittance is not particularly limited, but there is no need to excessively reduce the light transmittance, and it is preferably 1% or more, more preferably 10% or more, and particularly preferably 30% or more. In addition, the light transmittance in the present invention is measured as described in the examples described below.

From the viewpoint of controlling the light transmittance of the middle-surface peeling film (12) within the above range, it is preferable that the middle-surface peeling film (12) be colored. The coloring of the middle-surface peeling film (12) may be accomplished by coloring the substrate of the middle-surface peeling film (12) itself, but it is convenient to provide a coloring layer containing a pigment or dye on one side of the middle-surface peeling film (12). The pigment or dye to be used is not particularly limited, but examples thereof include white pigment (NX-501 White, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), black pigment (Multi Rack A903 Black, manufactured by TOYO INK CO., LTD.), and red pigment (NX-031 Red, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.). The amount of these pigments or dyes to be used is not particularly limited as long as the light transmittance of the middle-surface peeling film (12) can be controlled within the above range. When using the above pigment, the pigment may be blended in an amount of about 1 to 40 parts by mass per 100 parts by mass of the solid content of the coloring layer. The thickness of the coloring layer is not particularly limited, but from the viewpoint of not affecting the peelability of the middle-surface release film (12), it is preferably about 10 to 500 nm. It is preferable to provide the coloring layer on one side of the middle-surface release film (12) and to provide a release agent layer on the other side. In addition, a pigment or dye may be blended into the composition for the release agent layer to color the release agent layer.

In addition, from the viewpoint of improving the identification of the middle-surface peeling film (12), the haze of the middle-surface peeling film (12) is preferably 6% or more, more preferably 10% or more, and particularly preferably 20% or more. The upper limit of the haze is not particularly limited, but there is no need to excessively increase the haze, and it is preferably 70% or less, more preferably 60% or less, and particularly preferably 55% or less. In addition, the haze in the present invention is measured using a haze meter as described in the examples described later.

From the viewpoint of controlling the haze of the middle-surface release film (12) within the above range, it is preferable that at least one side of the middle-surface release film (12) is roughened. The roughening treatment may be performed on both sides of the middle-surface release film (12). The method for roughening the middle-surface release film (12) is not particularly limited, but for example, the surface of the substrate used for the middle-surface release film (12) is roughened by sandblasting or polishing with sandpaper or the like. The peeling treatment may be performed on the opposite side to the roughened side, or the peeling treatment may be performed on the roughened side. The degree of roughening is not particularly limited as long as the haze of the middle-surface release film (12) can be controlled within the above range.

(2.5 Control of the identification of the resin film formation film)

As described above, the present invention improves the accuracy of confirming the peeling of the middle-surface peeling film (12) by controlling the light transmittance and/or haze of the middle-surface peeling film (12). In addition, from the viewpoint of improving the accuracy of confirming that the resin film formation film remains in accordance with the shape of the workpiece, such as a ground wafer having light reflectivity or gloss, after peeling of the middle-surface peeling film (12), or from the viewpoint of improving the accuracy of confirming that the resin film formation film remains on a metal cutting blade having light reflectivity or gloss, it is preferable that the average value of the light reflectance at 400 to 800 nm of the contact surface of the resin film formation film (11) with the middle-surface peeling film (12) is 40% or less.

When the middle-surface peeling film (12) is peeled off from the resin film forming film (11), the surface of the resin film forming film (11) that was in contact with the middle-surface peeling film (12) is exposed. If this exposed surface can be confirmed, it can be confirmed that the middle-surface peeling film (12) has been peeled. Therefore, in order to confirm the surface of the resin film forming film (11) after peeling of the middle-surface peeling film by a sensor or the naked eye, the average value of the light reflectance at 400 to 800 nm of the surface of the resin film forming film (11) is preferably 40% or less, more preferably 32% or less, still more preferably 25% or less, still more preferably 18% or less, and particularly preferably 10% or less. In addition, the lower limit of the average value of the light reflectance is not particularly limited, but from the viewpoint of easier material design of the composition for the resin film forming film, it is preferably 0.1% or more, more preferably 1% or more, even more preferably 2% or more, and particularly preferably 3% or more. In addition, the light reflectance in the present invention is measured using an integrating sphere as described in the examples described later. The average value of the light reflectance at 400 to 800 nm of the surface of the resin film forming film (11) can be controlled by adjusting, for example, the material type, particle size, and content of the colorant and filler contained in the resin film forming film.

(3. Manufacturing method of sheet for forming resin film)

The method for producing a resin film forming film is not particularly limited. The film is produced using the composition for the resin film forming film described above, or a composition obtained by diluting the composition for the resin film forming film with a solvent (these two compositions are referred to herein as a “coating agent including a composition for a resin film forming film”). Examples of the diluting solvent include organic solvents such as aromatic hydrocarbons such as toluene, fatty acid esters such as ethyl acetate, ketones such as methyl ethyl ketone, aliphatic hydrocarbons such as hexane and heptane. These diluting solvents may be used singly, or two or more may be used in combination. The coating agent is prepared by mixing the components constituting the composition for the resin film forming film by a known method.

The obtained coating agent is applied to the peeling surface of the middle-surface 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, or a curtain coater, and dried as necessary, and then a mirror-surface release film (13) is laminated on the exposed surface of the resin film formation film (11), thereby obtaining a resin film formation sheet (10) according to the present embodiment. The resin film formation sheet (10) is preferably a roll body wound into a roll shape as a long sheet in which the width of the middle-surface release film, the width of the resin film formation film, and the width of the mirror-surface release film are the same after cutting and the cutting process has not yet been performed. In addition, the order of lamination is not particularly limited, and the coating agent may be applied to the mirror-surface release film. In addition, the coating agent may be applied to another resin film, dried as necessary, and the obtained resin film formation film may be transferred to the middle-surface release film or the mirror-surface release film. In addition, after laminating these films, they may be heated and pressurized by a heat roller, etc. From the viewpoint of workability during manufacturing, etc., they may be applied to the peeling surface of a middle-surface peeling film (12) and dried as necessary, and then a process-use peeling film may be laminated on the exposed surface of a resin film-forming film (11), and then the process-use peeling film may be peeled off and a hard-surface peeling film (13) may be attached.

(4. Work processing method)

In the resin film forming sheet (10) according to the present embodiment, the resin film forming film (11) may be processed by cutting into a predetermined shape (precut), but as described below, the cutting process may not be performed before attachment, and the film may be cut to fit the outer peripheral shape of the work after attachment to the work. The latter method will be described in detail below.

First, as shown in Fig. 1, a resin film forming sheet (10) that has not been processed for cutting is prepared. The hard surface release film (13) of the resin film forming sheet (10) is released. When removing the hard surface release film (13) from the resin film forming film (11), by satisfying the relationship F1 > F2, the removal of the hard surface release film (13) becomes easy, and the resin film forming film (11) can be reliably left on the middle surface release film (12).

As an example of a method for processing a work according to the present embodiment, a method for manufacturing a chip with a protective film attached by processing a wafer to which a resin film forming film is attached is described. Therefore, in the following, the resin film forming film is sometimes referred to as a “protective film forming film.”

A method for manufacturing a chip with a protective film attachment has at least the following steps 1 to 5.

Process 1: A process of peeling off a hard surface peeling film (13) from a sheet (10) for forming a protective film, and attaching a protective film forming film (11) to the back surface of a wafer.

Process 2: Process of cutting the protective film forming film (11) and the middle-surface peeling film (12) to fit the outer shape of the wafer

Process 3: Process of forming a protective film by forming a protective film

Process 4: Process of peeling off the middle-surface peeling film (12) from the protective film or protective film forming film

Process 5: Process of obtaining chips having multiple protective films or protective film-forming films attached by slicing a wafer having a protective film or protective film-forming film on its back surface

In process 1, the mirror-surface peeling film (13) of the protective film forming sheet (10) is peeled off, the protective film forming film (11) is exposed, and the exposed protective film forming film (11) is attached to the back surface of the wafer. Since the mirror-surface peeling film (13) has a lower peeling force than the middle-surface peeling film (12), the mirror-surface peeling film (13) can be peeled off smoothly. When attaching the protective film forming film (11) to the wafer, thermal compression bonding may be performed.

Thereafter, the attached protective film-forming film (11) and the middle-surface peeling film (12) are cut to fit the outer shape of the wafer (process 2), and a wafer with a protective film-forming film attached is obtained. In addition, in the case where the protective film-forming film (11) is non-curable, the protective film-forming film becomes a protective film at the time of completing process 1, but for convenience, it is expressed as a "protective film-forming film" here.

In process 3, the protective film forming film is protectively formed. If 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. In addition, if the protective film forming film (11) is energy ray curable, an energy ray-transmitting film may be used as the middle-surface peeling film (12), and energy rays may be incident from the middle-surface peeling film (12) side. If the protective film forming film (11) is non-curable, the protective film is formed at the time of completion of process 1.

In addition, the curing of the protective film forming film (11) may be performed before peeling off the middle-surface peeling film (12) (process 4) after processes 1 and 2, or may be performed after peeling off the middle-surface peeling film (12). In addition, the curing of the protective film forming film (11) may be performed after the dicing process (process 5) described later, or the chip to which the protective film forming film is attached may be picked up from the dicing sheet, and then the protective film forming film (11) may be cured.

Next, the middle-surface peeling film (12) is peeled off from the protective film or protective film forming film (11) (process 4). For example, in process 4, one or more protective film or protective film forming film attached wafers having the middle-surface peeling film (12) attached are arranged in a straight line so that the wafers do not overlap, each middle-surface peeling film (12) is peeled off and attached to a long adhesive tape called a tape, and then the middle-surface peeling film attached adhesive tape is moved in the direction of peeling off from the protective film or protective film forming film (11), whereby the middle-surface peeling film (12) can be peeled off. In the present invention, since the light transmittance and/or haze of the middle-surface peeling film (12) is controlled within a specific range, the peeling of the middle-surface peeling film (12) can be confirmed with high precision. Therefore, the transfer to the next process can be performed smoothly and reliably.

Next, the wafer with the protective film or the protective film-forming film attached is transferred onto a known dicing sheet, and the wafer with the protective film or the protective film-forming film attached is diced to obtain a chip having the protective film or the protective film-forming film (process 5). Thereafter, the dicing sheet is expanded in a planar direction as necessary, and the chip with the protective film or the protective film-forming film attached is picked up from the dicing sheet by a suction collet or the like. The chip with the protective film or the protective film-forming film attached that is picked up may be returned to the next process, or may be temporarily stored in a tray, tape, or the like, and returned to the next process after a predetermined period of time. The chip with the protective film or the protective film-forming film attached that is returned to the next process may be mounted on a substrate according to a conventional method.

(5. Variant example)

In the above, the case of creating a protective film using a resin film forming film was described, but as described above, an adhesive film may be created using a resin film forming film. In this case, the resin film forming film functions as a die bonding film. The die bonding film is composed of a film-shaped adhesive. The film-shaped adhesive may have a known composition and physical properties.

Above, the embodiments of the present invention have been described, but the present invention is not limited to the above embodiments, and various modifications may be made within the scope of the present invention.

[Example]

Hereinafter, the invention will be described in more detail using examples, but the present invention is not limited to these examples.

(Production of sheets for forming a resin film)

[Middle-sided peeling film]

A colored layer was formed on one side of a polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Corporation, trade name: DIAFOIL (registered trademark) T-100, thickness: 50 μm) by the method described in the table below, or a roughening treatment was performed, and a release treatment was performed using a composition for a release agent layer described below, thereby obtaining middle-surface release films Nos. 1 to 9 and 14.

In addition, a release treatment using a release agent layer composition described later was performed on one side of a polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Corporation, trade name: DIAFOIL (registered trademark) T-100, thickness: 50 µm), thereby obtaining a middle-surface release film No. 13. In addition, in middle-surface release films Nos. 10 to 12, a roughening treatment was performed on the side opposite to the release-treated side in middle-surface release film No. 13.

[Table 1]

DPHA: Dipentaerythritol hexaacrylate

Irg.184: Irgacure 184

MEK: Methyl ethyl ketone

<Composition for peeling layer>

The following composition for a peeling layer was prepared.

[Table 2]

The above raw materials were added to a mixed solvent of toluene and methyl ethyl ketone (toluene/methyl ethyl ketone = 1/1 (mass ratio)) in the mixing ratio (converted to solid content) shown in Table 2, and the total solid content was adjusted to 2 mass%, and a coating agent including a composition for a release agent layer was prepared, and the coating agent was applied to a PET film on which the above-mentioned colored layer had been formed or roughened so that the film thickness after drying became 0.15 μm, heated, and dried to form a release agent layer on the PET film, and middle-surface release films No. 1 to 9 and 14 were produced.

In addition, a coating agent including a similar composition for a release agent layer was prepared, and applied to the PET film described above so that the film thickness after drying became 0.15 ㎛, heated, and dried to form a release agent layer on the PET film, and a middle-surface release film No. 13 was produced.

In addition, separately, a coating agent including a similar composition for a release agent layer was prepared, applied to the PET film described above so that the film thickness after drying became 0.15 ㎛, heated, and dried to form a release agent layer on the PET film, and roughening was performed on the surface opposite to the release-treated surface, thereby producing a middle-surface release film No. 10 to 12.

[Light surface peeling film]

A coating agent containing the composition for a release agent layer was applied to a PET film (manufactured by Mitsubishi Chemical Corporation, trade name: DIAFOIL (registered trademark) T-100, thickness: 38 μm) so that the film thickness after drying became 0.15 μm, heated, and dried to form a release agent layer on the PET film, and a mirror-surface release film was produced. In addition, the release agent layer of the mirror-surface release film is the same as the release agent layer of the above-mentioned middle-surface release film, but since the PET film is thinner and furthermore, the coating agent containing the composition for a resin film forming film was applied to the middle-surface release film, dried, and then the mirror-surface release film was attached, it has a lighter peelability than the middle-surface release film.

[Coating agent comprising a composition for forming a resin film]

The following components were mixed in the mixing ratio (converted to solid content) shown in Table 3, and diluted with methyl ethyl ketone so that the solid content concentration became 50 mass%, thereby preparing a coating agent including a composition for a resin film forming film.

(A) Polymer component: Copolymer formed by copolymerizing 87 parts by mass of methyl acrylate and 13 parts by mass of 2-hydroxyethyl acrylate (weight average molecular weight: 450,000, glass transition temperature: 6°C)

(B) Curable component (thermosetting component)

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

(B-2) Dicyclopentadiene type epoxy resin (manufactured by DIC Corporation, EPICLON HP-7200, epoxy equivalent 254 to 264 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, CUREZOL 2PHZ)

(E) Filler: Epoxy-modified spherical silica filler (manufactured by ADMATECHS MINO COMPANY LIMITED, SC2050MA, average particle size 0.5㎛)

(F) Silane coupling agent: X-41-1056 manufactured by Shin-Etsu Chemical Co., Ltd.

(G) Colorant

(G-1) Organic black pigment (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., 6377 Black)

(G-2) Titanium oxide white pigment (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., NX-501 White)

[Table 3]

A coating agent including a composition for a prepared resin film forming film was applied to the peeling-treated surface of the above-described middle-surface release film, and dried at 100°C for 2 minutes to form a resin film forming film having a thickness of 25 μm. Subsequently, a mirror-surface release film was attached on the resin film forming film, to obtain a resin film forming sheet which is a laminate of the middle-surface release film/resin film forming film/mirrored release film. The attachment conditions were a temperature of 60°C, a pressure of 0.4 MPa, and a speed of 1 m/min. In this state, the film was left to stand for 48 hours in an environment of 23°C and a relative humidity of 50%.

Next, the sheet for forming the resin film was cut to a width of 220 mm and wound into a length of 50 m to make a roll.

Using the obtained resin film forming sheet, the following measurements and evaluations were performed.

[Peel strength F1 from the resin film forming film of the middle-surface peeling film]

From the obtained resin film forming sheet, a hard release film was peeled. On the surface of the resin film forming film exposed by peeling, a good adhesive PET (manufactured by TOYOBO CO., LTD., PET25A-4100) having a thickness of 25 ㎛ was attached with both adhesive surfaces by heat lamination (70°C, 1 m/min) to produce a laminate sample. The laminate sample was cut into 100 mm widths to produce a measurement sample. The back surface of the middle release film of the measurement sample was fixed to a hard support plate with double-sided tape.

Using a universal tensile tester (product name "AUTOGRAPH (registered trademark) AG-IS" manufactured by Shimadzu Corporation), a composite (integrated) body of a resin film-forming film/double-adhesive PET was peeled from a middle-sided peeling film at a peeling angle of 180° and a peeling speed of 1 m/min in an environment of 23°C and a relative humidity of 50%, and the load at that time was measured. The measurement distance was 100 mm in total, and the average of the measurement values for 80 mm excluding the first 10 mm and the last 10 mm was converted to the unit of mN/100 mm and taken as the peeling force F1. The results are shown in Table 4.

[Peel strength F2 from the resin film forming film of the hard surface peeling film]

The obtained resin film forming sheet was cut into 100 mm widths to produce a measurement sample. The back surface of the middle peeling 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 mirror-peelable film was peeled from a measurement sample, and the load at that time was measured under the same conditions as the measurement of F1 above, and was defined as the peeling force F2. The results are shown in Table 4.

[Method for evaluating light transmittance of a mid-surface peeling film]

The middle-surface release film, peeled off from the sheet for forming a resin film, was placed in the sample folder of a UV-Vis spectrophotometer ("UV-VIS-NIR SPECTROPHOTOMETER UV-3600" manufactured by Shimadzu Corporation). The transmittance was measured in the wavelength range of 190 to 1200 nm in the direct light receiving mode without using an integrating sphere. The light transmittance at 555 nm is shown in Table 4.

[Method for evaluating haze of a mid-surface peeling film]

For the middle-surface release film peeled off from the sheet for forming a resin film, the haze was measured in accordance with JIS K 7136 using a haze meter ("NDH-2000" manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD). The results are shown in Table 4.

[Method for evaluating the average value of light reflectance at 400 to 800 nm]

The surface release film was peeled off from the sheet for forming a resin film, and the surface of the resin film formation film was attached to a colorless and transparent soda lime glass plate (manufactured by Nippon Sheet Glass Company, Ltd., thickness 1.1 mm) without roughening (attachment conditions were: a laminating roller temperature of 50°C, a pressure of 0.3 MPa, and a speed of 1 m/min), and the middle surface release film was peeled off.

The amount of diffuse reflected light excluding specular reflected light (regular reflected light) was measured at 1 nm intervals by the SCE method in a wavelength range of 400 to 800 nm on the surface of the exposed resin film formation using a UV-Vis spectrophotometer ("UV-VIS-NIR SPECTROPHOTOMETER UV-3600" manufactured by Shimadzu Corporation) under the following conditions. In addition, the amount of diffuse reflected light was measured for a barium sulfate reference plate by the same method. As a sample folder, "Large Sample Room MPC-3100" manufactured by Shimadzu Corporation was used, and as an integrating sphere, "Integrating Sphere Accessory ISR-3100" manufactured by Shimadzu Corporation was used.

And, the ratio of the measurement value in the resin film-forming film to the measurement value in the reference plate ([measured value of light amount in the resin film-forming film] / [measured value of light amount in the reference plate] × 100), i.e., the relative reflectance of the resin film-forming film, was obtained per 1 nm. In the wavelength range of 400 to 800 nm, the values of the relative reflectance per 1 nm were added, and the total value was divided by the number of values of the added relative reflectance (i.e., 800 - 400 + 1 = 401), thereby calculating the average value of the light reflectance in the range of 400 to 800 nm. The results are shown in Table 4.

[Method for evaluating the arithmetic mean height Sa of the peeled surface]

For the middle-surface release film peeled off from the laminate (sheet for forming a resin film), the arithmetic mean height Sa was measured in accordance with ISO 25178. More specific measurement of Sa is as follows.

That is, using a scanning white light interference microscope ("VS-1550" manufactured by Hitachi High-Tech Science Corporation), the peel-treated surface of the middle-surface peeling film, which is the measurement target, was observed at a magnification of 50 times in the multiple-field mode. At this time, in the observation field, an area of 0.36 mm in the X-axis direction and 0.27 mm in the Y-axis direction was set, and 12 cells in total were observed by observing 3 columns in the X-axis direction and 4 rows in the Y-axis direction. Then, the images for the 12 cells were synthesized to form one 1.0 mm × 1.0 mm image, and Sa was measured for the entire area of one synthesized image. The results are shown in Table 4.

[Test to confirm peeling of the middle-surface peeling film on the sensor]

On a silicon mirror wafer having a diameter of 200 mm, an exposed resin film was attached by peeling off the mirror-like release film from the resin film forming sheet (attachment conditions were: a laminating roller temperature of 60°C, a pressure of 0.3 MPa, and a speed of 1 m/min). Thereafter, the resin film forming film and the middle-surface release film were cut into a circle according to the shape of the wafer using a steel cutting blade. Next, a long adhesive tape (release tape) having a width of 20 mm was attached to the opposite side of the middle-surface release film to the resin film forming film, and the middle-surface release film was peeled from the resin film forming film. A circular middle-surface peeling film with a peeled diameter of 200 mm was passed through a transmission sensor of FU-12 manufactured by KEYENCE CORPORATION at a traveling speed of 80 mm/sec, and a test was conducted to see whether the behavior before, during, and after passage of the middle-surface peeling film (i.e., whether the middle-surface peeling film was peeled and passed through the sensor) could be immediately and correctly confirmed. The results are shown in Table 4. Cases where peeling of the middle-surface peeling film could be confirmed were considered “possible,” and cases where it could not be confirmed were considered “impossible.”

[Table 4]

As shown in Table 4, the middle-surface peeling film used in the resin film forming sheet of the present invention has high identification, so that the peeling can be confirmed with certainty.

10: Sheet for forming a resin film (present embodiment)
11: Resin film formation film
12: Middle peeling film
13: Hard-surface peeling film

Claims (6)

A resin film forming film for forming a resin film,
A middle-side peeling film provided on one side of the above resin film forming film,
Having a hard-surface peeling film provided on the other side of the above resin film forming film,
When the peeling force of the above-mentioned middle-surface peeling film from the above-mentioned resin film forming film is F1, and the peeling force of the above-mentioned hard-surface peeling film from the above-mentioned resin film forming film is F2, the relationship F1 > F2 is satisfied,
The above-mentioned middle-surface peeling film is a sheet for forming a resin film, which satisfies either one or both of a light transmittance of 555 nm of 80% or less and a haze of 4% or more. In the first paragraph,
A sheet for forming a resin film, at least one side of the above-mentioned middle-surface peeling film being roughened. In the first paragraph,
The above-mentioned middle-surface peeling film is a colored sheet for forming a resin film. In the first paragraph,
A sheet for forming a resin film, wherein the average value of the light reflectance at 400 to 800 nm of the contact surface of the resin film forming film with the middle-surface peeling film is 40% or less. In the first paragraph,
A sheet for forming a resin film, wherein the arithmetic mean height Sa of the contact surface of the above-mentioned middle-surface peeling film and the resin film forming film is less than 0.03 ㎛. A process of peeling off the surface release film of the resin film forming sheet described in any one of claims 1 to 5 and attaching the exposed resin film forming film to a workpiece.
A method for processing a work, comprising: a process for peeling a middle-surface peeling film from a resin film forming film attached to a work; and a process for confirming peeling of the middle-surface peeling film.