JP7497299B2 - Film-like adhesive, laminated sheet, composite sheet, and method for producing laminate - Google Patents

Description

The present invention relates to a film-like adhesive, a laminated sheet, a composite sheet, and a method for producing a laminate.
This application claims priority based on Japanese Patent Application No. 2018-246839, filed in Japan on December 28, 2018, the contents of which are incorporated herein by reference.

When various parts constituting electronic devices are manufactured or processed, various film-like adhesives are used depending on the purpose.
For example, when mounting a semiconductor chip on the circuit formation surface of a substrate, a film adhesive is applied to the back surface of the semiconductor chip, and the semiconductor chip is bonded (die-bonded) to the circuit formation surface of the substrate via this film adhesive. When protecting the circuit formation surface of a chip such as a sensor, the circuit formation surface is covered with a light-transmitting cover via a light-transmitting film adhesive.

On the other hand, components equipped with such film-like adhesives may be exposed to high temperatures during heating processes such as solder reflow processes. In such cases, deterioration of the film-like adhesive due to the effects of heat may become a problem. For example, if a light-transmitting film-like adhesive discolors, it becomes difficult to read information through the film-like adhesive. Film-like adhesives contain resin components to achieve adhesive properties, and in some cases contain thermosetting components to impart thermosetting properties, but some of these components are unstable to heat. In other words, conventional film-like adhesives are prone to discoloration when heated.

As an example of a light-transmitting film-like adhesive, a die-bonding film for die bonding of semiconductor chips, which has a light transmittance of 80% or more at a wavelength of 1065 nm, has been disclosed (see Patent Document 1).

Japanese Patent No. 6310748

However, Patent Document 1 does not disclose any physical properties after heating, such as the color of the die bond film after heating.

The present invention aims to provide a film-like adhesive that has optical transparency before and after heating and is suppressed from discoloring after heating, a laminated sheet and a composite sheet that use the film-like adhesive, and a method for producing a laminate that uses the film-like adhesive.

The present invention provides a film-like adhesive for bonding a circuit-forming surface of a chip to a light-transmitting cover, wherein at least one surface of the film-like adhesive is substantially free of aromatic compounds.
In the film-like adhesive of the present invention, the film-like adhesive before being heated at 260°C may have a linear transmittance of 90% or more for light having a wavelength of 400 to 800 nm, and the film-like adhesive after being heated at 260°C for 10 minutes may have a linear transmittance of 85% or more for light having a wavelength of 400 to 800 nm, and the film-like adhesive may have a thickness of 10 to 40 μm.
The film-like adhesive of the present invention preferably contains an aliphatic epoxy compound.

The film-like adhesive of the present invention may contain an aliphatic phosphite as an antioxidant.
In the film-like adhesive of the present invention, the film-like adhesive contains an acrylic resin and an aliphatic polyvalent isocyanate-based crosslinking agent, and the acrylic resin may have a functional group capable of bonding with the crosslinking agent.
The present invention provides a laminate sheet comprising the film-like adhesive and a resin film provided on one surface of the film-like adhesive.
The present invention provides a composite sheet comprising the film-like adhesive and a dicing sheet provided on one side of the film-like adhesive, the dicing sheet comprising a substrate and a pressure-sensitive adhesive layer provided on one side of the substrate, the pressure-sensitive adhesive layer being disposed between the substrate and the film-like adhesive.
The present invention provides a method for manufacturing a laminate, in which a circuit formation surface of a chip is bonded to one side of the film-like adhesive, and a light-transmitting cover is bonded to the other side of the film-like adhesive, thereby obtaining a laminate in which the chip, the film-like adhesive, and the light-transmitting cover are stacked in this order.

The film-like adhesive of the present invention has optical transparency both before and after heating, and is suppressed from becoming discolored after heating.
By using the laminated sheet or composite sheet of the present invention provided with the film-like adhesive of the present invention, the film-like adhesive can be provided on a part to which it is to be applied.
According to the method for producing a laminate of the present invention, a laminate can be produced in which a chip, a film-like adhesive, and a light-transmitting cover are laminated in this order.

1 is a cross-sectional view showing a schematic example of a film-like adhesive and a laminate sheet according to one embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a schematic view of another example of a laminate sheet according to an embodiment of the present invention. FIG. 1 is a cross-sectional view illustrating a schematic example of a composite sheet according to an embodiment of the present invention. FIG. 1 is a cross-sectional view showing a schematic example of a laminate produced using a film-like adhesive according to one embodiment of the present invention. 1 is a cross-sectional view for illustrating an example of a method of using a composite sheet according to an embodiment of the present invention. 4 shows the results of FT-IR measurement of film-like adhesives in Examples and Comparative Examples.

◇Film-like adhesive The film-like adhesive of one embodiment of the present invention is a film-like adhesive for bonding the circuit formation surface of a chip to an optically transparent cover, and at least one surface of the film-like adhesive is substantially free of aromatic compounds.
A film-like adhesive that satisfies these conditions is suppressed in turbidity and coloration before and after heating at, for example, 260°C, and has a high in-line transmittance of light with a wavelength of 400 to 800 nm (sometimes abbreviated as "light (400 to 800 nm)" in this specification).

The film-like adhesive of the present embodiment can be used for bonding objects during the manufacture or processing of various parts that make up electronic devices.
For example, the circuit formation surface of a chip such as a sensor can be covered with a light-transmitting cover (protective cover) via the film-like adhesive. That is, the film-like adhesive can be used as a film for adhering a cover to the circuit formation surface of the chip.
In this case, as described above, the film-like adhesive has high light transmittance before and after heating and coloration is suppressed, so that the visual information present on the circuit formation surface of the chip can be viewed stably and with high precision through the light-transmitting cover and the film-like adhesive.

An example of a sensor that is covered by the optically transparent cover (protective cover) is a fingerprint sensor. However, this is just one example of a sensor.

In this specification, the surfaces of the substrate and chip on which circuits are formed are referred to as "circuit-forming surfaces."
In this specification, the mere description of a "chip" does not mean only a semiconductor chip, but also includes chips other than semiconductor chips.

The film-like adhesive of this embodiment is preferably thermosetting and preferably pressure-sensitive. For example, a film-like adhesive having both thermosetting and pressure-sensitive adhesive properties can be applied to various adherends by lightly pressing it against them in an uncured state. The film-like adhesive may also be softened by heating so that it can be applied to various adherends. The film-like adhesive eventually becomes a cured product with high impact resistance as it cures, and this cured product can retain sufficient adhesive properties even under harsh conditions of high temperature and high humidity.

The linear transmittance of light (400 to 800 nm) of the film-like adhesive of this embodiment before heating at 260°C (sometimes abbreviated as "linear transmittance before heating" in this specification) is preferably 90% or more, more preferably 91.5% or more, even more preferably 93% or more, and particularly preferably 94.5% or more. When the linear transmittance before heating is equal to or greater than the lower limit, the film-like adhesive before heating has a high property (sometimes abbreviated as "image recognizability" in this specification) that allows an image to be correctly recognized when viewed through the film-like adhesive.

The upper limit of the linear transmittance of light (400 to 800 nm) before heating is not particularly limited, and may be 100%.
For example, a film-like adhesive having a pre-heating linear transmittance of 99.8% or less is easier to manufacture.

The linear transmittance before heating of light (400 to 800 nm) can be appropriately adjusted within a range set by any combination of any of the lower limit values and upper limit values described above. For example, in one embodiment, the linear transmittance before heating is preferably 90 to 99.8%, more preferably 91.5 to 99.8%, even more preferably 93 to 99.8%, and particularly preferably 94.5 to 99.8%. However, these are just examples of the linear transmittance before heating.

The linear transmittance of light (400 to 800 nm) of the film-like adhesive of this embodiment after heating at 260°C for 10 minutes (sometimes abbreviated as "linear transmittance after heating" in this specification) is preferably 85% or more, and may be, for example, any one of 87.5% or more, 90% or more, and 94% or more. When the linear transmittance after heating is equal to or greater than the lower limit, the film-like adhesive after heating has high image recognition properties.

The upper limit of the linear transmittance after heating of light (400 to 800 nm) is not particularly limited, and may be 100%.
For example, a film-like adhesive having a linear transmittance after heating of 99.8% or less is easier to manufacture.

The linear transmittance after heating of light (400 to 800 nm) can be appropriately adjusted within a range set by any combination of any of the lower limit values and upper limit values described above. For example, in one embodiment, the linear transmittance after heating is preferably 85 to 99.8%, and may be, for example, any of 87.5 to 99.8%, 90 to 99.8%, and 94 to 99.8%. However, these are just examples of the linear transmittance after heating.

The linear transmittance before heating and linear transmittance after heating of light (400 to 800 nm) can be measured by a known method using a spectrophotometer.

The heating conditions of the film adhesive, 260°C and 10 minutes, when determining the linear transmittance after heating, are set taking into account the conditions in heating processes such as the solder reflow process.

The shear strength of the film-like adhesive of this embodiment is not particularly limited, but is preferably 20 N/2 mm or more, and may be, for example, any of 50 N/2 mm or more, 60 N/2 mm or more, 70 N/2 mm or more, and 78 N/2 mm or more. When the shear strength of the film-like adhesive is equal to or greater than the lower limit, the adhesive strength to the object to which it is applied is stronger.
In this specification, the unit "N/2mm□" is synonymous with "N/(2mm×2mm)."

The upper limit of the shear strength of the film-like adhesive is not particularly limited.
For example, a film-like adhesive having a shear strength of 300 N/2 mm square or less is easier to manufacture.

The shear strength of the film-like adhesive can be adjusted as appropriate within a range set by any combination of any of the lower limit values and upper limit values described above. For example, in one embodiment, the shear strength is preferably 20 to 300 N/2 mm□, and may be, for example, any of 50 to 300 N/2 mm□, 60 to 300 N/2 mm□, 70 to 300 N/2 mm□, and 78 to 300 N/2 mm□. However, these are just examples of the shear strength.

In this embodiment, the shear strength of the film-like adhesive is measured by the method described below.
(Method for measuring shear strength of film adhesive)
A test piece is prepared by using a film-like adhesive having a size of 2 mm x 2 mm and a thickness of 20 μm, a copper plate having a size of 30 mm x 30 mm and a thickness of 300 μm, and a silicon chip, with one entire surface of the film-like adhesive being attached to the surface of the silicon chip and the other entire surface being attached to the surface of the copper plate. At least one side of this test piece is aligned with the side of the film-like adhesive and the silicon chip.
Under a temperature condition of 23°C, a force is applied to both the film adhesive and the silicon chip on the aligned side of the test piece in a direction parallel to the other side of the film adhesive at a speed of 200 μm/s, and the maximum force applied until the film adhesive is destroyed is adopted as the shear strength (N/2 mm□) of the film adhesive.

In the film-like adhesive, at least one surface is preferably substantially free of aromatic compounds, and both surfaces are preferably substantially free of aromatic compounds.
The single-layer film-like adhesive generally has a high degree of compositional uniformity without any bias in its composition, and therefore there is no significant difference in the types and contents of the components on both sides of the single-layer film-like adhesive, or even if there is a significant difference, the effect brought about by this is negligible.
If at least one surface of the single-layer film-like adhesive is substantially free of aromatic compounds, then the entire film-like adhesive and the other surface can be determined to be substantially free of aromatic compounds.

In this specification, regardless of the part of the film-like adhesive, "the film-like adhesive is substantially free of aromatic compounds" means that the film-like adhesive does not contain any aromatic compounds at all, or, even if it does contain any aromatic compounds, the effect caused by this is so slight that it can be ignored, and the film-like adhesive exhibits the same properties as when it does not contain aromatic compounds.

In this embodiment, the surface of the film-like adhesive (i.e., the one surface or both surfaces) is substantially free of aromatic compounds, which can be confirmed by the absence of an inflection point in the curve showing the transmittance in the wavenumber range of 3050 to 2990 cm ⁻¹ when the target surface of the film-like adhesive is analyzed by Fourier transform infrared spectroscopy (sometimes abbreviated as “FT-IR” in this specification). The main functional groups identified in the wavenumber range of 3050 to 2990 cm ⁻¹ are aromatic cyclic groups only, and if there is no inflection point in the curve showing the transmittance in this wavenumber range, it can be determined that there is no aromatic cyclic group in the analyzed surface and that no aromatic compound is contained. Here, “there is no inflection point” is synonymous with the absence of peaks other than noise in the curve showing the transmittance.

The film-like adhesive may consist of one layer (single layer) or may consist of two or more layers. If it consists of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited.

In this specification, not limited to the case of film-like adhesives, "multiple layers may be the same or different" means "all layers may be the same, all layers may be different, or only some layers may be the same," and further, "multiple layers are different" means "at least one of the constituent materials and thicknesses of each layer is different from each other."

The thickness of the film-like adhesive is preferably 10 to 40 μm, and may be, for example, any of 10 to 35 μm, 10 to 30 μm, and 10 to 25 μm, any of 13 to 40 μm, 16 to 40 μm, and 19 to 40 μm, and any of 13 to 35 μm, 16 to 30 μm, and 19 to 25 μm. When the thickness of the film-like adhesive is equal to or greater than the lower limit, the adhesive strength of the film-like adhesive to the object to be adhered is stronger. When the thickness of the film-like adhesive is equal to or less than the upper limit, the linear transmittance of the film-like adhesive to light (for example, light (400 to 800 nm)) is high, regardless of whether or not heating is performed.
Here, "thickness of the film adhesive" means the thickness of the entire film adhesive; for example, the thickness of a film adhesive consisting of multiple layers means the total thickness of all layers that make up the film adhesive.

Preferred examples of the film-like adhesive include those in which the linear transmittance of light (400 to 800 nm) before heating is 90% or more, the linear transmittance of light (400 to 800 nm) after heating is 85% or more, and the thickness of the film-like adhesive is 10 to 40 μm.

The above-mentioned physical properties of the film-like adhesive (the linear transmittance of light (400-800 nm) before heating, the linear transmittance of light (400-800 nm) after heating, shear strength, and FT-IR characteristics) can be adjusted, for example, by adjusting the type and content of the components contained in the film-like adhesive.

Preferred examples of the film-like adhesive include those containing one or more compounds selected from the group consisting of an acrylic resin (a), an epoxy compound (b1), and a phosphorus-based antioxidant (z).

<<Adhesive composition>>
The film-like adhesive can be formed using an adhesive composition containing its constituent materials (e.g., one or more selected from the group consisting of an acrylic resin (a), an epoxy compound (b1), and a phosphorus-based antioxidant (z). For example, the adhesive composition can be applied to a surface on which the film-like adhesive is to be formed, and then dried as necessary, to form a film-like adhesive at a desired site.
The ratio of the contents of the components that do not vaporize at room temperature in the adhesive composition is usually the same as the ratio of the contents of the components in the film-like adhesive. In this specification, "room temperature" means a temperature that is not particularly cooled or heated, that is, an ordinary temperature, and examples of this include a temperature of 15 to 25°C.

The adhesive composition may be applied by any known method, such as using an air knife coater, blade coater, bar coater, gravure coater, roll coater, roll knife coater, curtain coater, die coater, knife coater, screen coater, Mayer bar coater, kiss coater, etc.

The drying conditions for the adhesive composition are not particularly limited, but when the adhesive composition contains a solvent described below, it is preferable to heat-dry the adhesive composition. The adhesive composition containing a solvent is preferably dried, for example, at 70 to 130° C. for 10 seconds to 5 minutes.
The components of the film-like adhesive and the adhesive composition will be described in detail below.

<Acrylic resin (a)>
The acrylic resin (a) is a component that can be regarded as being formed by a polymerization reaction of one or more members selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid esters, and derivatives thereof.
In this specification, unless otherwise specified, the term "derivative" refers to a compound having a structure in which one or more groups of an original compound are replaced with other groups (substituents). Here, the term "group" includes not only an atomic group formed by bonding multiple atoms, but also a single atom.
The acrylic resin (a) is a resin component that imparts film-forming properties, flexibility, and the like to the film-like adhesive, and also improves the adhesiveness (applicability) to an object to be adhered, such as the chip.

In this specification, the term "(meth)acrylic acid" is a concept that encompasses both "acrylic acid" and "methacrylic acid." The same applies to terms similar to (meth)acrylic acid.

The adhesive composition and the film-like adhesive may contain only one type of acrylic resin (a) or two or more types, and if there are two or more types, the combination and ratio of these can be selected arbitrarily.

The acrylic resin (a) may be a known acrylic polymer.
The weight average molecular weight (Mw) of the acrylic resin (a) is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000. When the weight average molecular weight of the acrylic resin (a) is within such a range, it becomes easy to adjust the adhesive strength between the film-like adhesive and the adherend within a preferred range.
On the other hand, when the weight average molecular weight of the acrylic resin (a) is equal to or greater than the lower limit, the shape stability (stability over time during storage) of the film-like adhesive is improved. Also, when the weight average molecular weight of the acrylic resin (a) is equal to or less than the upper limit, the film-like adhesive is more likely to conform to the uneven surface of the adherend, and the occurrence of voids between the adherend and the film-like adhesive is further suppressed.
In this specification, unless otherwise specified, the "weight average molecular weight" is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

The glass transition temperature (Tg) of the acrylic resin (a) is preferably -60 to 70°C, and more preferably -30 to 50°C. When the Tg of the acrylic resin (a) is equal to or greater than the lower limit, the adhesive strength between the film-like adhesive and the adherend is suppressed, and, for example, when picked up, the chip equipped with the film-like adhesive can be more easily detached from the dicing sheet described below. When the Tg of the acrylic resin (a) is equal to or less than the upper limit, the adhesive strength between the film-like adhesive and the adherend is improved.

Examples of the (meth)acrylic acid ester constituting the acrylic resin (a) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, and n-nonyl (meth)acrylate. (meth)acrylic acid alkyl esters in which the alkyl group constituting the alkyl ester has a chain structure having 1 to 18 carbon atoms, such as isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (myristyl (meth)acrylate), pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (palmityl (meth)acrylate), heptadecyl (meth)acrylate, and octadecyl (meth)acrylate (stearyl (meth)acrylate);
(meth)acrylic acid cycloalkyl esters such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate;
(Meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate;
(Meth)acrylic acid cycloalkenyl esters such as (meth)acrylic acid dicyclopentenyl ester;
(meth)acrylic acid cycloalkenyloxyalkyl esters such as (meth)acrylic acid dicyclopentenyloxyethyl ester;
(Meth)acrylic acid imide;
glycidyl group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate;
hydroxyl group-containing (meth)acrylic acid esters such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate;
Examples of such esters include (meth)acrylic acid esters containing a substituted amino group, such as N-methylaminoethyl (meth)acrylate. Here, the term "substituted amino group" refers to a group having a structure in which one or two hydrogen atoms of an amino group are substituted with a group other than a hydrogen atom.

The acrylic resin (a) may be, for example, a resin obtained by copolymerizing one or more monomers selected from the group consisting of (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-methylolacrylamide, in addition to the (meth)acrylic acid ester.

The monomers constituting the acrylic resin (a) may be one type or two or more types, and if there are two or more types, the combination and ratio of these can be selected arbitrarily.

In addition to the above-mentioned hydroxyl groups, the acrylic resin (a) may have functional groups that can bond with other compounds, such as vinyl groups, (meth)acryloyl groups, amino groups, carboxy groups, and isocyanate groups. These functional groups, including the hydroxyl groups of the acrylic resin (a), may be bonded to other compounds via the crosslinking agent (f) described below, or may be bonded directly to other compounds without the crosslinking agent (f). When the acrylic resin (a) is bonded to other compounds via the functional groups, the reliability of the package obtained using the film-like adhesive tends to be improved.

Preferred acrylic resins (a) include, for example, those having functional groups capable of bonding with the crosslinking agent (f) described below.

In the adhesive composition, the ratio of the content of the acrylic resin (a) to the total content of all components other than the solvent (i.e., the ratio of the content of the acrylic resin (a) to the total mass of the film-like adhesive in the film-like adhesive) is preferably 10 to 90 mass%, more preferably 15 to 70 mass%, and even more preferably 20 to 65 mass%, and may be, for example, either 30 to 55 mass% or 30 to 50 mass%. When the ratio is equal to or greater than the lower limit, the structure of the film-like adhesive is more stabilized. When the ratio is equal to or less than the upper limit, it becomes easier to increase the amount of components other than the acrylic resin (a), such as the epoxy compound (b1) and the phosphorus-based antioxidant (z), used, and the effects of using components other than the acrylic resin (a) can be more easily obtained.

<Epoxy compound (b1)>
The epoxy compound (b1) may be either a resin component or a non-resin component.
Examples of the epoxy compound (b1) include known compounds, such as bifunctional or higher functional epoxy compounds, such as polyfunctional epoxy resins, biphenyl compounds, bisphenol A diglycidyl ether and hydrogenated products thereof, orthocresol novolac epoxy resins, dicyclopentadiene type epoxy resins, biphenyl type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, phenylene skeleton type epoxy resins, and triazine type alicyclic epoxy compounds.

As the epoxy compound (b1), an epoxy compound having an unsaturated hydrocarbon group may be used. The epoxy compound having an unsaturated hydrocarbon group has a higher compatibility with the acrylic resin (a) than the epoxy compound not having an unsaturated hydrocarbon group. Therefore, by using the epoxy compound (b1) having an unsaturated hydrocarbon group, the reliability of the package obtained using the film-like adhesive is improved.

An example of an epoxy compound (b1) having an unsaturated hydrocarbon group is a compound having a structure in which a portion of the epoxy group of a polyfunctional epoxy compound is converted to a group having an unsaturated hydrocarbon group. Such a compound can be obtained, for example, by subjecting an epoxy group to an addition reaction with (meth)acrylic acid or a derivative thereof.

Moreover, examples of the epoxy compound (b1) having an unsaturated hydrocarbon group include compounds in which a group having an unsaturated hydrocarbon group is directly bonded to an aromatic ring or the like constituting the epoxy compound.
The unsaturated hydrocarbon group is a polymerizable unsaturated group, and specific examples thereof include an ethenyl group (vinyl group), a 2-propenyl group (allyl group), a (meth)acryloyl group, and a (meth)acrylamide group, with an acryloyl group being preferred.

The number average molecular weight of the epoxy compound (b1) (in other words, the epoxy resin (b1)) which is the resin component is not particularly limited, but from the standpoint of the curability of the film-like adhesive and the strength and heat resistance of the cured product of the film-like adhesive, it is preferably 300 to 30,000, more preferably 400 to 10,000, and particularly preferably 500 to 3,000.
The epoxy equivalent of the epoxy compound (b1) is preferably from 100 to 1000 g/eq, and more preferably from 120 to 600 g/eq.

The epoxy compound (b1) contained in the adhesive composition and the film-like adhesive may be one type or two or more types, and if there are two or more types, the combination and ratio of these can be selected arbitrarily.

The epoxy compound (b1) is preferably an aliphatic compound, that is, the film-like adhesive preferably contains an aliphatic epoxy compound.
In this specification, "aliphatic compound" means a compound that has an aliphatic group and does not have an aromatic group. The "aliphatic group" includes linear aliphatic groups and aliphatic cyclic groups (also known as alicyclic groups). The "aromatic group" includes aromatic hydrocarbon groups and aromatic heterocyclic groups.
By containing an aliphatic compound as the epoxy compound (b1) in the adhesive composition and film-like adhesive, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only an aliphatic compound (in other words, not containing an aromatic compound), the above-mentioned effect of suppressing discoloration is significantly enhanced.

It is preferable that the epoxy compound (b1) does not have one or more selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C≡C), a cyano group (-C≡N), and an aromatic group.
By containing an epoxy compound (b1) in the adhesive composition and film-like adhesive that does not have these bonds or groups, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only those that do not have these bonds or groups (in other words, not containing those that have these bonds or groups), the above-mentioned effect of suppressing discoloration is significantly enhanced.

The epoxy compound (b1) is preferably an aliphatic compound and does not have one or more selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C═C), and a cyano group (-C≡N). In other words, the film-like adhesive preferably contains an aliphatic epoxy compound that does not have one or more selected from the group consisting of a triple bond between carbon atoms, a double bond between carbon atoms, and a cyano group.
By containing an aliphatic compound that does not have these bonds or groups as the epoxy compound (b1) in the adhesive composition and film-like adhesive, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only an aliphatic compound that does not have these bonds or groups (in other words, not containing an aliphatic compound that has these bonds or groups), the above-mentioned effect of suppressing discoloration is significantly enhanced.

In the adhesive composition and the film-like adhesive, the content of the epoxy compound (b1) is preferably 5 to 500 parts by mass relative to 100 parts by mass of the acrylic resin (a), and may be, for example, any of 5 to 200 parts by mass, 5 to 150 parts by mass, 5 to 110 parts by mass, and 5 to 100 parts by mass, or any of 10 to 110 parts by mass, 25 to 110 parts by mass, and 40 to 110 parts by mass. When the content of the epoxy compound (b1) is in such a range, it becomes easier to adjust the adhesive strength between the film-like adhesive and the resin film or dicing sheet described later.

<Phosphorus-Based Antioxidant (z)>
The film adhesive contains the phosphorus-based antioxidant (z), so that discoloration before and after heating is further suppressed.
The phosphorus-based antioxidant (z) is not particularly limited as long as it has a phosphorus atom as a constituent atom and has an antioxidant effect.
Examples of the phosphorus-based antioxidant (z) include compounds in which the oxidation number of phosphorus is 3.

The adhesive composition and the film-like adhesive may contain only one type of phosphorus-based antioxidant (z), or two or more types. If there are two or more types, the combination and ratio of these can be selected arbitrarily.

The phosphorus-based antioxidant (z) is preferably an aliphatic compound.
By containing an aliphatic compound as the phosphorus-based antioxidant (z) in the adhesive composition and film-like adhesive, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only an aliphatic compound (in other words, not containing an aromatic compound), the above-mentioned effect of suppressing discoloration is significantly enhanced.

It is preferable that the phosphorus-based antioxidant (z) does not have one or more types selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C═C), a cyano group (—C≡N), and an aromatic group.
By containing, as a phosphorus-based antioxidant (z), one that does not have these bonds or groups, the adhesive composition and the film-like adhesive have a higher effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C), and by containing only those that do not have these bonds or groups (in other words, not containing those that have these bonds or groups), the above-mentioned effect of suppressing discoloration is significantly increased.

It is preferable that the phosphorus-based antioxidant (z) is an aliphatic compound and does not have one or more types selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C≡C), and a cyano group (-C≡N).
By containing an aliphatic compound that does not have these bonds or groups as the phosphorus-based antioxidant (z) in the adhesive composition and film-like adhesive, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only an aliphatic compound that does not have these bonds or groups (in other words, not containing an aliphatic compound that has these bonds or groups), the above-mentioned effect of suppressing discoloration is significantly enhanced.

The phosphorus-based antioxidant (z) is preferably a phosphite ester, since it exhibits a stable antioxidant effect.
Among these, the phosphorus-based antioxidant (z) is more preferably an aliphatic phosphite ester, and even more preferably an aliphatic trialkyl phosphite ester.
That is, the film adhesive preferably contains a phosphite ester as an antioxidant, more preferably contains an aliphatic phosphite ester, and even more preferably contains an aliphatic trialkyl phosphite ester.

Examples of the aliphatic trialkyl phosphite include triethyl phosphite ((C ₂ H ₅ O) ₃ P), tris(2-ethylhexyl)phosphite ((CH ₃ CH ₂ CH 2 CH _{2 CH} (CH ₂ CH ₃ )CH ₂ O) ₃ P), tridecyl phosphite ((C ₁₀ H ₂₁ O) ₃ P), trilauryl phosphite ((C ₁₂ H ₂₅ O) ₃ P), tris(tridecyl)phosphite ((C ₁₃ H ₂₇ O) ₃ P), tristearyl phosphite ((C ₁₈ H ₃₇ O) ₃ P), bis(decyl)pentaerythritol diphosphite (C ₁₀ H ₂₁ OP(OCH ₂ ) ₂ C(CH ₂ O) ₂ POC ₁₀ H ₂₁ ), bis(tridecyl)pentaerythritol diphosphite (C ₁₃ H ₂₇ OP(OCH ₂ ) ₂ C(CH ₂ O) ₂ POC ₁₃ H ₂₇ ), distearyl pentaerythritol diphosphite (C ₁₈ H ₃₇ OP(OCH ₂ ) ₂ C(CH ₂ O) ₂ POC ₁₈ H ₃₇ ), and hydrogenated bisphenol A-pentaerythritol phosphite polymer (a polymer having a repeating unit represented by the formula "-(OC ₆ H ₁₂ C(CH ₃ ) ₂ C ₆ H ₁₂ OP(OCH ₂ ) ₂ C(CH ₂ O) ₂ P)-").

In the adhesive composition, the ratio of the content of the phosphorus-based antioxidant (z) to the total content of all components other than the solvent (i.e., the ratio of the content of the phosphorus-based antioxidant (z) in the film-like adhesive to the total mass of the film-like adhesive) is preferably 0.1 to 5 mass%, more preferably 0.2 to 3 mass%, and even more preferably 0.3 to 1.5 mass%, and may be, for example, 0.3 to 1 mass%. When the ratio is equal to or greater than the lower limit, the effect of using the phosphorus-based antioxidant (z) is more pronounced. When the ratio is equal to or less than the upper limit, excessive use of the phosphorus-based antioxidant (z) is suppressed.

In order to improve various physical properties, the film-like adhesive may contain, in addition to the acrylic resin (a), the epoxy compound (b1), and the phosphorus-based antioxidant (z), other components not corresponding to any of the above, as necessary.
Examples of other components contained in the film-like adhesive include a phenolic resin (b2), a curing accelerator (c), a filler (d), a coupling agent (e), a crosslinking agent (f), an energy ray curable resin (g), a photopolymerization initiator (h), an antioxidant (y) other than the phosphorus-based antioxidant (z) (sometimes abbreviated as "other antioxidant (y)" in this specification), a thermoplastic resin (x) other than the acrylic resin (a) (sometimes abbreviated as "thermoplastic resin (x)" in this specification), and a general-purpose additive (i).

<Phenol resin (b2)>
The phenol resin (b2) functions as a heat curing agent for the epoxy compound (b1).
In the present embodiment, when the epoxy compound (b1) and the phenol resin (b2) are used in combination, the combination functions as an epoxy-based thermosetting resin. In the present embodiment, such an epoxy-based thermosetting resin may be referred to as an "epoxy-based thermosetting resin (b)."

The phenolic resin (b2) may have two or more phenolic hydroxyl groups in one molecule as functional groups capable of reacting with epoxy groups.

Examples of phenolic resins (b2) include polyfunctional phenolic resins, novolac-type phenolic resins, dicyclopentadiene-type phenolic resins, aralkyl-type phenolic resins, etc.

The phenol resin (b2) may have an unsaturated hydrocarbon group.
Examples of the other phenol resin (b2) having an unsaturated hydrocarbon group include a compound having a structure in which some of the hydroxyl groups of the phenol resin are substituted with a group having an unsaturated hydrocarbon group, and a compound having a structure in which a group having an unsaturated hydrocarbon group is directly bonded to an aromatic ring of the phenol resin.
The unsaturated hydrocarbon group in the phenol resin (b2) is the same as the unsaturated hydrocarbon group in the above-mentioned epoxy compound having an unsaturated hydrocarbon group.

It is preferable that the phenolic resin (b2) has a high softening point or glass transition temperature, since this makes it easier to adjust the adhesive strength of the film-like adhesive.

The number average molecular weight of the phenolic resin (b2) is preferably 300 to 30,000, more preferably 400 to 10,000, and particularly preferably 500 to 3,000.

The phenolic resin (b2) contained in the adhesive composition and the film-like adhesive may be one type or two or more types, and if there are two or more types, the combination and ratio of these can be selected arbitrarily.

When a phenolic resin (b2) is used, the ratio of the content of the phenolic resin (b2) to the total content of all components other than the solvent in the adhesive composition (i.e., the ratio of the content of the phenolic resin (b2) to the total mass of the film-like adhesive in the film-like adhesive) is not particularly limited, but is preferably 10 mass% or less, more preferably 7.5 mass% or less, and even more preferably 5 mass% or less. By having this ratio be equal to or less than the upper limit, the effect of suppressing coloration after heating the film-like adhesive (e.g., heating at 260°C) is increased.
That is, an example of a preferred film-like adhesive containing phenolic resin (b2) is one in which the content of phenolic resin (b2) in the film-like adhesive relative to the total mass of the film-like adhesive is 10 mass% or less.

When a phenolic resin (b2) is used, the lower limit of the ratio of the content of the phenolic resin (b2) to the total content of all components other than the solvent in the adhesive composition (i.e., the ratio of the content of the phenolic resin (b2) in the film-like adhesive to the total mass of the film-like adhesive) is not particularly limited.
For example, in order to obtain the effect of using the phenol resin (b2) more significantly, the ratio is preferably 0.5% by mass or more.

When phenolic resin (b2) is used, the ratio can be appropriately adjusted within a range set by any combination of the above-mentioned lower limit value and any of the upper limit values. For example, in one embodiment, the ratio is preferably 0.5 to 10 mass%, more preferably 0.5 to 7.5 mass%, and even more preferably 0.5 to 5 mass%.

When a phenolic resin (b2) is used, the content of the phenolic resin (b2) in the adhesive composition and the film-like adhesive may be, for example, any one of 3 to 30 parts by mass, 3 to 25 parts by mass, and 3 to 20 parts by mass, or any one of 5 to 30 parts by mass, 10 to 30 parts by mass, and 15 to 30 parts by mass, or any one of 5 to 25 parts by mass, and 10 to 20 parts by mass, relative to 100 parts by mass of the epoxy compound (b1).

<Curing Accelerator (c)>
The curing accelerator (c) is a component for adjusting the curing speed of the adhesive composition and the film-like adhesive.
Preferred examples of the curing accelerator (c) include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole (imidazoles in which one or more hydrogen atoms are substituted with groups other than hydrogen atoms); organic phosphines such as tributylphosphine, diphenylphosphine, and triphenylphosphine (phosphines in which one or more hydrogen atoms are substituted with organic groups); tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, and other tetraphenylboron salts; and inclusion compounds in which the imidazoles are used as guest compounds.

The adhesive composition and the film-like adhesive may contain only one type of curing accelerator (c) or two or more types. If there are two or more types, the combination and ratio of these can be selected arbitrarily.

When the curing accelerator (c) is used, the content of the curing accelerator (c) in the adhesive composition and the film-like adhesive is preferably 0.01 to 7 parts by mass, more preferably 0.1 to 4 parts by mass, relative to 100 parts by mass of the total content of the epoxy compound (b1) and the phenolic resin (b2). When the content of the curing accelerator (c) is equal to or greater than the lower limit, the effect of using the curing accelerator (c) is more pronounced. When the content of the curing accelerator (c) is equal to or less than the upper limit, for example, the effect of suppressing the highly polar curing accelerator (c) from migrating to the adhesive interface with the adherend and segregating in the film-like adhesive under high temperature and high humidity conditions is enhanced, and the reliability of the package obtained using the film-like adhesive is further improved. In addition, when the phenolic resin (b2) is not used, the total content of the epoxy compound (b1) and the phenolic resin (b2) means the content of the epoxy compound (b1).

<Filler (d)>
By containing the filler (d), the thermal expansion coefficient of the film adhesive can be easily adjusted, and by optimizing this thermal expansion coefficient for the object to which the film adhesive is applied, the reliability of the package obtained using the film adhesive is further improved. Furthermore, by containing the filler (d) in the film adhesive, it is also possible to reduce the moisture absorption rate of the cured product of the film adhesive and improve the heat dissipation properties.

The filler (d) may be either an organic filler or an inorganic filler, but is preferably an inorganic filler.
Preferred inorganic fillers include, for example, powders of silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, boron nitride, and the like; beads obtained by spheronizing these inorganic fillers; surface-modified products of these inorganic fillers; single crystal fibers of these inorganic fillers; glass fibers, and the like.
Among these, the inorganic filler is preferably silica or a surface-modified silica product.

The average particle size of the filler (d) is not particularly limited, but is preferably 10 to 100 nm, more preferably 10 to 80 nm, and even more preferably 10 to 60 nm. When the average particle size of the filler (d) is equal to or less than the upper limit, the turbidity of the film-like adhesive is highly suppressed, and the linear transmittance of light (400 to 800 nm) before heating and the linear transmittance after heating of the film-like adhesive are improved, resulting in higher image recognizability of the film-like adhesive before and after heating. When the average particle size of the filler (d) is equal to or more than the lower limit, the effect of using the filler (d) is more pronounced.
In this specification, unless otherwise specified, the term "average particle size" refers to the particle size (D ₅₀ ) value at an integrated value of 50% in a particle size distribution curve determined by a laser diffraction scattering method.

The adhesive composition and the film-like adhesive may contain only one type of filler (d) or two or more types, and if there are two or more types, the combination and ratio of these can be selected arbitrarily.

When filler (d) is used, the ratio of the content of filler (d) to the total content of all components other than the solvent in the adhesive composition (i.e., the ratio of the content of filler (d) to the total mass of the film-like adhesive in the film-like adhesive) is preferably 7.5 to 50 mass%, and may be, for example, either 10 to 45 mass% or 10 to 40 mass%. When the content of filler (d) is in such a range, it becomes easier to adjust the thermal expansion coefficient.

<Coupling Agent (e)>
The film-like adhesive contains a coupling agent (e) to improve its adhesiveness and adhesion to the adherend. In addition, the film-like adhesive contains a coupling agent (e) to improve the water resistance of the cured product without impairing its heat resistance. The coupling agent (e) has a functional group capable of reacting with an inorganic compound or an organic compound.

The coupling agent (e) is preferably a compound having a functional group capable of reacting with a functional group possessed by the acrylic resin (a), the epoxy thermosetting resin (b) or the like, and is more preferably a silane coupling agent.
Preferred examples of the silane coupling agent include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxymethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, and 3-(2-aminoethylamino)propyltrimethoxysilane. Examples of the organosiloxane include phenylmethyldiethoxysilane, 3-(phenylamino)propyltrimethoxysilane, 3-anilinopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazole silane, and oligomeric or polymeric organosiloxane.

The coupling agent (e) is preferably an aliphatic compound.
By containing an aliphatic compound as the coupling agent (e) in the adhesive composition and film-like adhesive, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only an aliphatic compound (in other words, not containing an aromatic compound), the above-mentioned effect of suppressing discoloration is significantly enhanced.

It is preferable that the coupling agent (e) does not have one or more types selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C≡C), a cyano group (—C≡N), and an aromatic group.
By containing a coupling agent (e) in the adhesive composition and film-like adhesive that does not have these bonds or groups, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only those that do not have these bonds or groups (in other words, not containing those that have these bonds or groups), the above-mentioned effect of suppressing discoloration is significantly enhanced.

It is preferable that the coupling agent (e) is an aliphatic compound and does not have one or more types selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C≡C), and a cyano group (-C≡N).
By containing an aliphatic compound that does not have these bonds or groups as the coupling agent (e) in the adhesive composition and film-like adhesive, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only an aliphatic compound that does not have these bonds or groups (in other words, not containing an aliphatic compound that has these bonds or groups), the above-mentioned effect of suppressing discoloration is significantly enhanced.

Among the coupling agents (e), more specifically, examples of aliphatic compounds (aliphatic coupling agents) include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxymethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminopropyltrimethoxysilane, Examples of suitable organosiloxanes include bis(3-(triethoxysilylpropyl)tetrasulfane, bis(3-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propylmethyldiethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and oligomeric or polymeric organosiloxanes.

The coupling agent (e) contained in the adhesive composition and the film-like adhesive may be one type or two or more types, and if there are two or more types, the combination and ratio of these can be selected arbitrarily.

When a coupling agent (e) is used, the content of the coupling agent (e) in the adhesive composition and film-like adhesive is preferably 0.03 to 20 parts by mass, more preferably 0.05 to 10 parts by mass, and particularly preferably 0.1 to 5 parts by mass, per 100 parts by mass of the total content of the acrylic resin (a) and the epoxy thermosetting resin (b). When the content of the coupling agent (e) is equal to or greater than the lower limit, the effects of using the coupling agent (e), such as improved dispersibility of the filler (d) in the resin and improved adhesion of the film-like adhesive to the adherend, are more significantly obtained. When the content of the coupling agent (e) is equal to or less than the upper limit, the generation of outgassing is further suppressed.

<Crosslinking Agent (f)>
When the acrylic resin (a) has a functional group such as a vinyl group, (meth)acryloyl group, amino group, hydroxyl group, carboxyl group, isocyanate group, etc., which can bond with the above-mentioned other compounds, the adhesive composition and the film-like adhesive may contain a crosslinking agent (f) for bonding the functional group with other compounds to crosslink them. By crosslinking with the crosslinking agent (f), the initial adhesive strength and cohesive strength of the film-like adhesive can be adjusted.

Examples of the crosslinking agent (f) include organic polyvalent isocyanate compounds, organic polyvalent imine compounds, metal chelate-based crosslinking agents (crosslinking agents having a metal chelate structure), aziridine-based crosslinking agents (crosslinking agents having an aziridinyl group), etc.

Examples of the organic polyisocyanate compound include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, and alicyclic polyisocyanate compounds (hereinafter, these compounds may be collectively referred to as "aromatic polyisocyanate compounds, etc."); trimers, isocyanurates, and adducts of the aromatic polyisocyanate compounds, etc.; and terminal isocyanate urethane prepolymers obtained by reacting the aromatic polyisocyanate compounds, etc. with polyol compounds. The "adducts" refer to the reaction products of the aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, or alicyclic polyisocyanate compounds with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, or castor oil. Examples of the adduct include a xylylene diisocyanate adduct of trimethylolpropane, an isophorone diisocyanate adduct of trimethylolpropane, a tolylene diisocyanate adduct of trimethylolpropane, a hexamethylene diisocyanate adduct of trimethylolpropane, etc., which will be described later. In addition, the term "terminal isocyanate urethane prepolymer" refers to a prepolymer having a urethane bond and an isocyanate group at the terminal of the molecule.

More specifically, examples of the organic polyisocyanate compound include 2,4-tolylene diisocyanate; 2,6-tolylene diisocyanate; 1,3-xylylene diisocyanate; 1,4-xylylene diisocyanate; diphenylmethane-4,4'-diisocyanate; diphenylmethane-2,4'-diisocyanate; 3-methyldiphenylmethane diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4,4'-diisocyanate; dicyclohexylmethane-2,4'-diisocyanate; a compound in which one or more of tolylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are added to all or some of the hydroxyl groups of a polyol such as trimethylolpropane; lysine diisocyanate, and the like.

Examples of the organic polyvalent imine compounds include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinyl propionate, tetramethylolmethane-tri-β-aziridinyl propionate, N,N'-toluene-2,4-bis(1-aziridinecarboxamide)triethylenemelamine, etc.

When an organic polyisocyanate compound is used as the crosslinking agent (f), it is preferable to use a hydroxyl group-containing polymer as the acrylic resin (a). When the crosslinking agent (f) has an isocyanate group and the acrylic resin (a) has a hydroxyl group, a crosslinked structure can be easily introduced into the film-like adhesive by the reaction between the crosslinking agent (f) and the acrylic resin (a).

The crosslinking agent (f) is preferably an aliphatic compound.
By containing an aliphatic compound as the crosslinking agent (f) in the adhesive composition and film-like adhesive, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only an aliphatic compound (in other words, not containing an aromatic compound), the above-mentioned effect of suppressing discoloration is significantly enhanced.

It is preferable that the crosslinking agent (f) does not have one or more types selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C═C), a cyano group (—C≡N), and an aromatic group.
By containing a crosslinking agent (f) in the adhesive composition and film-like adhesive that does not have these bonds or groups, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only those that do not have these bonds or groups (in other words, not containing those that have these bonds or groups), the above-mentioned effect of suppressing discoloration is significantly enhanced.

It is preferable that the crosslinking agent (f) is an aliphatic compound and does not have one or more types selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C≡C), and a cyano group (-C≡N).
By containing an aliphatic compound that does not have these bonds or groups as the crosslinking agent (f) in the adhesive composition and film-like adhesive, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only an aliphatic compound that does not have these bonds or groups (in other words, not containing an aliphatic compound that has these bonds or groups), the above-mentioned effect of suppressing discoloration is significantly enhanced.

The crosslinking agent (f) is preferably an aliphatic organic polyisocyanate compound (aliphatic polyisocyanate crosslinking agent) in that it has a particularly high effect of suppressing the above-mentioned coloring and has excellent properties as a crosslinking agent.
More specific examples of the aliphatic polyisocyanate crosslinking agent include 2,4-tolylene diisocyanate; 2,6-tolylene diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4,4'-diisocyanate;dicyclohexylmethane-2,4'-diisocyanate; a compound in which one or more of tolylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate are added to all or a part of the hydroxyl groups of a polyol such as trimethylolpropane; lysine diisocyanate, and the like.

When focusing on the acrylic resin (a) and the crosslinking agent (f), the film-like adhesive has a particularly high effect of suppressing the above-mentioned coloring and has excellent properties, so it is preferable that the crosslinking agent (f) contains the aliphatic polyvalent isocyanate crosslinking agent, and that the acrylic resin (a) contains one having a functional group capable of bonding with the aliphatic polyvalent isocyanate crosslinking agent.

The crosslinking agent (f) contained in the adhesive composition and the film-like adhesive may be one type or two or more types, and if there are two or more types, the combination and ratio of these may be selected arbitrarily.

When a crosslinking agent (f) is used, the content of the crosslinking agent (f) in the adhesive composition and film-like adhesive is preferably 0.3 to 12 parts by mass, more preferably 0.3 to 3.5 parts by mass, and even more preferably 0.3 to 2 parts by mass, per 100 parts by mass of the acrylic resin (a). When the content of the crosslinking agent (f) is equal to or greater than the lower limit, the effect of using the crosslinking agent (f) is more pronounced. Furthermore, when the content of the crosslinking agent (f) is equal to or less than the upper limit, excessive use of the crosslinking agent (f) is suppressed.

<Energy Ray Curable Resin (g)>
The adhesive composition and the film-like adhesive may contain an energy ray-curable resin (g). By containing the energy ray-curable resin (g), the film-like adhesive can change its properties by irradiation with energy rays.

In this specification, the term "energy ray" refers to electromagnetic waves or charged particle beams that have an energy quantum, and examples of such beams include ultraviolet rays, radioactive rays, and electron beams.
The ultraviolet light can be irradiated by using, for example, a high-pressure mercury lamp, a fusion lamp, a xenon lamp, a black light, an LED lamp, etc. as an ultraviolet light source. The electron beam can be generated by an electron beam accelerator or the like.
In this specification, "energy ray curable" means a property that is cured by irradiation with energy rays, and "non-energy ray curable" means a property that is not cured even when irradiated with energy rays.

The energy ray curable resin (g) is obtained by polymerizing (curing) an energy ray curable compound.
Examples of the energy ray-curable compound include compounds having at least one polymerizable double bond in the molecule, and acrylate compounds having a (meth)acryloyl group are preferred.

Examples of the acrylate-based compound include (meth)acrylates containing a chain aliphatic skeleton such as trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate; (meth)acrylates containing a cyclic aliphatic skeleton such as dicyclopentanyl di(meth)acrylate; polyalkylene glycol (meth)acrylates such as polyethylene glycol di(meth)acrylate; oligoester (meth)acrylates; urethane (meth)acrylate oligomers; epoxy-modified (meth)acrylates; polyether (meth)acrylates other than the polyalkylene glycol (meth)acrylates; and itaconic acid oligomers.

The weight average molecular weight of the energy ray curable resin (g) is preferably 100 to 30,000, and more preferably 300 to 10,000.

The adhesive composition may contain only one type of energy ray-curable resin (g) or two or more types. If there are two or more types, the combination and ratio of these can be selected arbitrarily.

When an energy ray curable resin (g) is used, the content of the energy ray curable resin (g) in the adhesive composition relative to the total mass of the adhesive composition is preferably 1 to 95 mass%, more preferably 5 to 90 mass%, and particularly preferably 10 to 85 mass%.

<Photopolymerization initiator (h)>
When the adhesive composition and the film-like adhesive contain an energy ray-curable resin (g), they may contain a photopolymerization initiator (h) in order to efficiently proceed with the polymerization reaction of the energy ray-curable resin (g).

Examples of the photopolymerization initiator (h) include benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, and benzoin dimethyl ketal; acetophenone compounds such as acetophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and 2,2-dimethoxy-1,2-diphenylethane-1-one; and acylphosphine oxides such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide. Examples of the compounds include aryl ether compounds; sulfide compounds such as benzyl phenyl sulfide and tetramethylthiuram monosulfide; α-ketol compounds such as 1-hydroxycyclohexyl phenyl ketone; azo compounds such as azobisisobutyronitrile; titanocene compounds such as titanocene; thioxanthone compounds such as thioxanthone; peroxide compounds; diketone compounds such as diacetyl; benzyl; dibenzyl; benzophenone; 2,4-diethylthioxanthone; 1,2-diphenylmethane; 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone; and quinone compounds such as 1-chloroanthraquinone and 2-chloroanthraquinone.
Examples of the photopolymerization initiator (h) include photosensitizers such as amines.

The photopolymerization initiator (h) is preferably an aliphatic compound.
By containing an aliphatic compound as the photopolymerization initiator (h) in the adhesive composition and film-like adhesive, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only an aliphatic compound (in other words, not containing an aromatic compound), the above-mentioned effect of suppressing discoloration is significantly enhanced.

It is preferable that the photopolymerization initiator (h) does not have one or more types selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C≡C), a cyano group (-C≡N), and an aromatic group.
By containing, as a photopolymerization initiator (h), an adhesive composition and a film-like adhesive that do not have these bonds or groups, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only those that do not have these bonds or groups (in other words, not containing those that have these bonds or groups), the above-mentioned effect of suppressing discoloration is significantly enhanced.

It is preferable that the photopolymerization initiator (h) is an aliphatic compound and does not have one or more types selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C≡C), and a cyano group (-C≡N).
By containing an aliphatic compound that does not have these bonds or groups as the photopolymerization initiator (h) in the adhesive composition and film-like adhesive, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only an aliphatic compound that does not have these bonds or groups (in other words, not containing an aliphatic compound that has these bonds or groups), the above-mentioned effect of suppressing discoloration is significantly enhanced.

Among the photopolymerization initiators (h), more specific examples of the aliphatic compound (aliphatic photopolymerization initiator) include acylphosphine oxide compounds; sulfide compounds such as tetramethylthiuram monosulfide; azo compounds such as azobisisobutyronitrile; peroxide compounds; diketone compounds such as diacetyl; and photosensitizers such as amines.
Among the compounds exemplified here, examples of the photopolymerization initiator (h) that is an aliphatic compound and does not have one or more types selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C≡C), and a cyano group (-C≡N) include compounds other than azobisisobutyronitrile.

The photopolymerization initiator (h) contained in the adhesive composition and the film-like adhesive may be one type or two or more types, and if there are two or more types, the combination and ratio of these can be selected arbitrarily.

When a photopolymerization initiator (h) is used, the content of the photopolymerization initiator (h) in the adhesive composition is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, and particularly preferably 2 to 5 parts by mass, per 100 parts by mass of the energy ray-curable resin (g).

<Other antioxidants (y)>
The adhesive composition and film-like adhesive may contain the other antioxidant (y) as described above, provided the effect of the present invention is not impaired.
The other antioxidant (y) is not particularly limited as long as it is an antioxidant other than the phosphorus-based antioxidant (z), and may be either an organic compound or an inorganic compound.

The other antioxidant (y) contained in the adhesive composition and the film-like adhesive may be one type or two or more types, and if there are two or more types, the combination and ratio thereof can be selected arbitrarily.

When another antioxidant (y) is used, the content of the other antioxidant (y) in the adhesive composition and the film-like adhesive is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 1 part by mass or less, per 100 parts by mass of the phosphorus-based antioxidant (z). By having the content of the other antioxidant (y) be equal to or less than the upper limit, discoloration of the film-like adhesive before and after heating is further suppressed.

It is preferable that the adhesive composition and film-like adhesive do not contain other antioxidants (y).

<Thermoplastic resin (x)>
The adhesive composition and the film-like adhesive may contain the thermoplastic resin (x) as long as the effects of the present invention are not impaired.
By using the thermoplastic resin (x), for example, when picking up, the chip equipped with the film-like adhesive can be more easily detached from the dicing sheet described below, and the film-like adhesive can more easily conform to the uneven surface of the adherend, thereby further suppressing the occurrence of voids, etc. between the adherend and the film-like adhesive.

The thermoplastic resin (x) is not particularly limited as long as it is a thermoplastic resin other than the acrylic resin (a).
Examples of the thermoplastic resin include polyester, polyurethane, phenoxy resin, polybutene, polybutadiene, and polystyrene.

The weight average molecular weight of the thermoplastic resin (x) is preferably 1,000 to 100,000, and more preferably 3,000 to 80,000.

The glass transition temperature (Tg) of the thermoplastic resin (x) is preferably -30 to 150°C, and more preferably -20 to 120°C.

The thermoplastic resin (x) contained in the adhesive composition and the film-like adhesive may be one type or two or more types, and if there are two or more types, the combination and ratio of these can be selected arbitrarily.

When a thermoplastic resin (x) is used, the content of the thermoplastic resin (x) in the adhesive composition and the film-like adhesive is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 1 part by mass or less, per 100 parts by mass of the acrylic resin (a). When the content of the thermoplastic resin (x) is equal to or less than the upper limit, the effect of using the acrylic resin (a) can be more significantly obtained.

It is preferable that the adhesive composition and film-like adhesive do not contain a thermoplastic resin (x).

<General-purpose additives (i)>
The general-purpose additive (i) may be a known one and may be selected arbitrarily according to the purpose, and is not particularly limited. Preferred general-purpose additives (I) include, for example, plasticizers, antistatic agents, colorants (dyes, pigments), gettering agents, etc.

When the general-purpose additive (i) is an organic compound, such general-purpose additive (i) (abbreviated as "organic general-purpose additive" in this specification) is preferably an aliphatic compound.
By containing an aliphatic compound as an organic general-purpose additive in the adhesive composition and film-like adhesive, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only an aliphatic compound (in other words, not containing an aromatic compound), the above-mentioned effect of suppressing discoloration is significantly enhanced.

It is preferable that the organic general-purpose additive does not have one or more selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C≡C), a cyano group (-C≡N), and an aromatic group.
By containing an organic general-purpose additive in the adhesive composition and film-like adhesive that does not have these bonds or groups, the effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C) is enhanced, and by containing only those that do not have these bonds or groups (in other words, not containing anything that has these bonds or groups), the above-mentioned effect of suppressing discoloration is significantly enhanced.

It is preferable that the organic general-purpose additive is an aliphatic compound and does not have one or more types selected from the group consisting of a triple bond between carbon atoms (C≡C), a double bond between carbon atoms (C≡C), and a cyano group (-C≡N).
By containing an aliphatic compound that does not have these bonds or groups as an organic general-purpose additive, the adhesive composition and film-like adhesive have a higher effect of suppressing discoloration after heating of the film-like adhesive (e.g., heating at 260°C), and by containing only an aliphatic compound that does not have these bonds or groups (in other words, not containing an aliphatic compound that has these bonds or groups), the above-mentioned effect of suppressing discoloration is significantly increased.

The adhesive composition and film-like adhesive may contain only one type of general-purpose additive (i), or two or more types. When there are two or more types, the combination and ratio thereof can be selected arbitrarily.
The content of the general-purpose additive (i) in the adhesive composition and film-like adhesive is not particularly limited and may be appropriately selected depending on the purpose.

<Solvent>
The adhesive composition preferably further contains a solvent. An adhesive composition containing a solvent has good handleability.
The solvent is not particularly limited, but preferred examples thereof include hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutyl alcohol (2-methylpropan-1-ol), and 1-butanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; and amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone.
The adhesive composition may contain one type of solvent, or two or more types. When two or more types are contained, the combination and ratio of the solvents can be selected arbitrarily.

The solvent contained in the adhesive composition is preferably methyl ethyl ketone or the like, since this allows the components in the adhesive composition to be mixed more uniformly.

<<Method of manufacturing adhesive composition>>
The adhesive composition can be obtained by blending the respective components constituting the adhesive composition.
The order of addition of the components is not particularly limited, and two or more components may be added simultaneously.
When a solvent is used, the solvent may be used by mixing it with any of the other ingredients to pre-dilute the ingredients, or the solvent may be used by mixing it with any of the other ingredients without pre-diluting the ingredients.

The method for mixing the components during blending is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer or stirring blade, a method of mixing using a mixer, a method of mixing by applying ultrasound, etc.
The temperature and time during addition and mixing of each component are not particularly limited as long as the components do not deteriorate, and may be adjusted appropriately. The temperature is preferably 15 to 30°C.

Figure 1 is a cross-sectional view showing a schematic diagram of a film-like adhesive according to one embodiment of the present invention. Note that the figures used in the following explanation may show enlarged essential parts for the sake of convenience in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

The film-like adhesive 13 shown here has a first release film 151 on one surface (sometimes referred to herein as the "first surface") 13a, and a second release film 152 on the other surface (sometimes referred to herein as the "second surface") 13b opposite the first surface 13a. Here, the reference numeral 109 is given to the laminate sheet thus constructed by laminating the first release film 151, the film-like adhesive 13, and the second release film 152 in this order in the thickness direction.
Such a film-like adhesive 13 (laminate sheet 109) is suitable for storage, for example, in a roll form.

The film-like adhesive 13 has the above-mentioned light transmittance. For example, at least one of the first surface 13a and the second surface 13b of the film-like adhesive 13 is substantially free of aromatic compounds.
The thickness of the film adhesive 13 is preferably 10 to 40 μm.
The film-like adhesive 13 can be formed using the adhesive composition described above.

The first release film 151 and the second release film 152 may both be of known types.
The first release film 151 and the second release film 152 may be the same as each other, or may be different from each other, for example, in that the peeling force required to peel them from the film-like adhesive 13 is different from each other.

When either the first release film 151 or the second release film 152 is removed from the film-like adhesive 13 shown in FIG. 1, the resulting exposed surface becomes the surface to be attached to the object to which it is to be attached. Here, an example of the object to which it is to be attached is the chip, etc. In the case of the chip, the surface to which the film-like adhesive 13 is to be attached becomes the circuit formation surface.

A preferred embodiment of the film-like adhesive is, for example, a film-like adhesive for bonding a circuit-forming surface of a chip to a light-transmitting cover,
At least one surface of the film adhesive is substantially free of aromatic compounds;
A test piece was prepared using the film-like adhesive measuring 2 mm x 2 mm and 20 μm thick, a copper plate measuring 30 mm x 30 mm and 300 μm thick, and a silicon chip, with one entire surface of the film-like adhesive attached to the surface of the silicon chip and the other entire surface attached to the surface of the copper plate, with the sides of the film-like adhesive and the silicon chip aligned, and a force was applied to both the film-like adhesive and the silicon chip on the aligned sides in a direction parallel to the other surface of the film-like adhesive at a speed of 200 μm/s under a temperature condition of 23°C, and when the maximum force applied until the film-like adhesive was destroyed was taken as the shear strength of the film-like adhesive (N/2 mm□), the shear strength was 20 N/2 mm□ or more.

A preferred embodiment of the film-like adhesive is, for example, a film-like adhesive for bonding a circuit-forming surface of a chip to a light-transmitting cover,
At least one surface of the film adhesive is substantially free of aromatic compounds;
The film adhesive contains a phosphorus-based antioxidant (z),
The phosphorus-based antioxidant (z) is an aliphatic compound that does not have one or more types selected from the group consisting of a triple bond between carbon atoms, a double bond between carbon atoms, and a cyano group.

A preferred embodiment of the film-like adhesive is, for example, a film-like adhesive for bonding a circuit-forming surface of a chip to a light-transmitting cover,
At least one surface of the film adhesive is substantially free of aromatic compounds;
The film-like adhesive contains an epoxy compound (b1),
The epoxy compound (b1) is an aliphatic compound and does not have one or more selected from the group consisting of a triple bond between carbon atoms, a double bond between carbon atoms, and a cyano group.

A preferred embodiment of the film-like adhesive is, for example, a film-like adhesive for bonding a circuit-forming surface of a chip to a light-transmitting cover,
At least one surface of the film adhesive is substantially free of aromatic compounds;
The film-like adhesive contains an acrylic resin (a) and a crosslinking agent (f),
the acrylic resin (a) has a functional group capable of bonding with the crosslinking agent (f);
The crosslinking agent (f) is an aliphatic compound that does not have one or more types selected from the group consisting of a triple bond between carbon atoms, a double bond between carbon atoms, and a cyano group.

A preferred embodiment of the film-like adhesive is, for example, a film-like adhesive for bonding a circuit-forming surface of a chip to a light-transmitting cover,
At least one surface of the film adhesive is substantially free of aromatic compounds;
The film adhesive contains a filler (d),
The filler (d) has an average particle size of 10 to 100 nm.

Laminated Sheet and Composite Sheet A laminated sheet according to one embodiment of the present invention is configured to include the film-like adhesive and a resin film provided on one surface of the film-like adhesive.
Moreover, a composite sheet according to one embodiment of the present invention comprises the film-like adhesive and a dicing sheet provided on one side of the film-like adhesive, the dicing sheet comprising a substrate and a pressure-sensitive adhesive layer provided on one side of the substrate, the pressure-sensitive adhesive layer being disposed between the substrate and the film-like adhesive.

The laminate sheet may have a resin film on at least one side of the film-like adhesive, and may have a resin film on only one side or on both sides (i.e., on the one side and the other side opposite the one side).

In the laminated sheet, when the resin films are provided on both sides of the film-like adhesive, these resin films may be the same or different, and the combination of these resin films is not particularly limited.

The resin film may consist of one layer (single layer) or may consist of two or more layers. If it consists of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited.

The resin film may be a sheet whose only constituent material is resin, or a sheet whose constituent materials are resin and other components, with resin being the main constituent material.

Examples of the resin that is a constituent material of the resin film include polyethylenes such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); polyolefins other than polyethylene such as polypropylene, polybutene, polybutadiene, polymethylpentene, and norbornene resin; ethylene-based copolymers (copolymers obtained using ethylene as a monomer) such as ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, and ethylene-norbornene copolymer; vinyl chloride-based resins (copolymers obtained using ethylene as a monomer) such as polyvinyl chloride and vinyl chloride copolymers. Examples of the polyester resin include poly(vinyl resins); polystyrene; polycycloolefins; polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalenedicarboxylate, and wholly aromatic polyesters in which all structural units have aromatic cyclic groups; copolymers of two or more of the above polyesters; poly(meth)acrylic acid esters; polyurethanes; polyurethane acrylates; polyimides; polyamides; polycarbonates; fluororesins; polyacetals; modified polyphenylene oxides; polyphenylene sulfides; polysulfones; and polyether ketones.
Further, the resin may be, for example, a polymer alloy such as a mixture of the polyester and other resins. The polymer alloy of the polyester and other resins is preferably one in which the amount of the resin other than the polyester is relatively small.
Examples of the resin include crosslinked resins in which one or more of the resins exemplified above are crosslinked; and modified resins such as ionomers using one or more of the resins exemplified above.

The resin film may be a release film or a substrate, which will be described later. The substrate will be described in detail later.

The release film may be, for example, a multi-layer film comprising a resin layer and a release treatment layer provided on one side of the resin layer.

The release film can be produced by subjecting one surface of the resin layer to a release treatment.
The resin layer can be produced by molding or coating a resin composition containing a resin, and drying it as necessary.

The resin that is the constituent material of the resin layer is the same as the resin that is the constituent material of the resin film.
The resin layer can be peeled off using various known release agents, such as alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, or wax-based release agents.
The release agent is preferably an alkyd-based, silicone-based or fluorine-based release agent in terms of heat resistance.

The resin layer may consist of one layer (single layer) or two or more layers. If it consists of multiple layers, these layers may be the same or different from each other, and the combination of these layers is not particularly limited.

An example of a laminated sheet having the release film provided as a resin film on both sides of the film-like adhesive is laminated sheet 109 shown in Figure 1.

An example of the laminate sheet having a resin film provided only on one side of the film-like adhesive is the laminate sheet 108 shown in FIG.
In FIG. 2 and subsequent figures, the same components as those shown in the figures already described are given the same reference numerals as in the figures already described, and detailed description thereof will be omitted.

The laminated sheet 108 shown here is configured with a resin film 19 on the first surface 13 a of the film-like adhesive 13 .
The resin film 19 is as described above, and may be a release film (for example, the first release film 151 or the second release film 152 in FIG. 1) or a substrate to be described later.

The thickness of the resin film is not particularly limited and can be set arbitrarily depending on the purpose.
The resin film may have a thickness of, for example, 10 to 200 μm.

The laminated sheet of this embodiment is not limited to the one shown in Figure 2, and may have some of the configurations shown in Figure 2 changed or removed, or may have other configurations added to those described above, as long as the effects of the present invention are not impaired. More specifically, it is as follows.

For example, the laminate sheet of this embodiment may have nothing on the second side of the film-like adhesive, but may have a jig adhesive layer in the area near the peripheral edge of the second side of the film-like adhesive for fixing the laminate sheet to a jig such as a ring frame.
The adhesive layer for the jig may be, for example, a single-layer structure containing an adhesive component, or a multi-layer structure in which layers containing adhesive components are laminated on both sides of a core sheet.

For example, when the laminate sheet is viewed in plan from above the film-like adhesive side or the resin film side, the surface areas of the film-like adhesive and the resin film may be equal or nearly equal, but in the laminate sheet of this embodiment, the surface area of the film-like adhesive may be smaller than the surface area of the resin film, and a portion of the resin film may be exposed. In that case, for example, at least the peripheral portion in the width direction of the resin film may be exposed without being covered by the film-like adhesive. Such a laminate sheet may have the above-mentioned jig adhesive layer on the exposed surface of the resin film.

FIG. 3 is a cross-sectional view that illustrates an example of a composite sheet according to an embodiment of the present invention.
The composite sheet 101 shown here comprises a film-like adhesive 13 and a dicing sheet 10 provided on a second surface 13b of the film-like adhesive 13, and the dicing sheet 10 comprises a substrate 11 and an adhesive layer 12 provided on one surface 11a (sometimes referred to as the "first surface" in this specification) of the substrate 11, with the adhesive layer 12 being disposed between the substrate 11 and the film-like adhesive 13.
In other words, the composite sheet 101 is constructed by laminating the substrate 11, the pressure-sensitive adhesive layer 12, and the film-like adhesive 13 in this order in the thickness direction.
The surface 10a of the dicing sheet 10 facing the film-like adhesive 13 (sometimes referred to as the "first surface" in this specification) is the same as the surface 12a of the pressure-sensitive adhesive layer 12 opposite the substrate 11 (sometimes referred to as the "first surface" in this specification).

The composite sheet 101 further includes a release film 15 on the film-like adhesive 13 .
In the composite sheet 101, an adhesive layer 12 is laminated on a first surface 11a of a substrate 11, a film-like adhesive 13 is laminated over the entire surface or almost the entire surface of the first surface 12a of the adhesive layer 12, and a release film 15 is laminated over the entire surface or almost the entire surface of the first surface 13a of the film-like adhesive 13.

The dicing sheet 10 may be a known one.
The substrate 11 and the adhesive layer 12 in the dicing sheet 10 will be described in order.

The substrate 11 in the dicing sheet 10 is in the form of a sheet or film, and examples of its constituent materials include various resins. Examples of the resin that is the constituent material of the dicing sheet 10 include the same resins as the constituent material of the resin film in the laminate sheet.

The resin constituting the base material may be one type or two or more types, and if there are two or more types, the combination and ratio of these can be selected arbitrarily.

The substrate may consist of one layer (single layer) or may consist of two or more layers. If it consists of multiple layers, these layers may be the same or different, and there are no particular limitations on the combination of these layers.

The thickness of the substrate 11 is preferably 50 to 300 μm, and more preferably 60 to 150 μm. When the thickness of the substrate 11 is in this range, the flexibility of the composite sheet 101 and the ease of application to an object to which the composite sheet 101 is applied are improved.
Here, the "thickness of the substrate" means the thickness of the entire substrate. For example, the thickness of a substrate consisting of multiple layers means the total thickness of all layers constituting the substrate.

It is preferable that the substrate 11 has a high thickness precision, i.e., that the thickness variation is suppressed regardless of the part. Among the above-mentioned constituent materials, examples of materials that can be used to form a substrate with such a high thickness precision include polyethylene, polyolefins other than polyethylene, polyethylene terephthalate, and ethylene-vinyl acetate copolymer.

In addition to the main constituent materials such as the resin, the substrate 11 may contain various known additives such as fillers, colorants, antistatic agents, antioxidants, organic lubricants, catalysts, softeners (plasticizers), etc.

The substrate 11 may be transparent or opaque, may be colored according to the purpose, and may have other layers vapor-deposited thereon.

In order to improve adhesion to other layers (here, the pressure-sensitive adhesive layer 12) provided thereon, the substrate 11 may have its surface subjected to roughening treatment such as sandblasting or solvent treatment, or oxidation treatment such as corona discharge treatment, electron beam irradiation treatment, plasma treatment, ozone/ultraviolet radiation treatment, flame treatment, chromate treatment, or hot air treatment.
The surface of the substrate 11 may be treated with a primer.
In addition, the substrate 11 may have an antistatic coating layer; a layer that prevents the substrate 11 from adhering to other sheets or to an adsorption table when the composite sheets are stacked and stored.

The substrate 11 can be manufactured by a known method. For example, a substrate 11 containing a resin can be manufactured by molding a resin composition containing the resin.

The adhesive layer 12 in the dicing sheet 10 is in the form of a sheet or film, and contains an adhesive.
Examples of the adhesive include adhesive resins such as acrylic resins, urethane resins, rubber resins, silicone resins, epoxy resins, polyvinyl ethers, polycarbonates, and ester resins, with acrylic resins being preferred.

In this specification, the term "adhesive resin" includes both resins that are adhesive and resins that are adhesive. For example, the adhesive resins include not only resins that are adhesive themselves, but also resins that become adhesive when used in combination with other components such as additives, and resins that become adhesive in the presence of a trigger such as heat or water.

The adhesive layer 12 may consist of one layer (single layer) or may consist of two or more layers. If it consists of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited.

The thickness of the pressure-sensitive adhesive layer 12 is not particularly limited, but is preferably 1 to 100 μm, more preferably 1 to 60 μm, and particularly preferably 1 to 30 μm.
Here, "the thickness of the adhesive layer" means the thickness of the entire adhesive layer, and for example, the thickness of an adhesive layer consisting of multiple layers means the total thickness of all layers that make up the adhesive layer.

The adhesive layer 12 may be formed using an energy ray curable adhesive or a non-energy ray curable adhesive. That is, the adhesive layer 12 may be either energy ray curable or non-energy ray curable. The physical properties of the energy ray curable adhesive layer 12 before and after curing can be easily adjusted. For example, by curing the energy ray curable adhesive layer 12, the adhesive strength to the object to which it is applied can be easily adjusted.

The adhesive layer 12 can be formed using an adhesive composition containing an adhesive. For example, the adhesive composition can be applied to the surface on which the adhesive layer 12 is to be formed, and dried as necessary, to form the adhesive layer 12 at the desired location. The ratio of the contents of the components in the adhesive composition that do not vaporize at room temperature is usually the same as the ratio of the contents of the components in the adhesive layer 12. In this specification, "room temperature" means a temperature that is not particularly cooled or heated, that is, an ordinary temperature, and examples of such temperatures include temperatures of 15 to 25°C.

The adhesive composition may be applied by known methods, such as using various coaters such as an air knife coater, blade coater, bar coater, gravure coater, roll coater, roll knife coater, curtain coater, die coater, knife coater, screen coater, Mayer bar coater, or kiss coater.

When the adhesive layer 12 is provided on the substrate 11, for example, an adhesive composition may be applied to the substrate 11 and dried as necessary to laminate the adhesive layer 12 on the substrate 11. When the adhesive layer 12 is provided on the substrate 11, for example, an adhesive composition may be applied to a release film and dried as necessary to form the adhesive layer 12 on the release film, and the exposed surface of the adhesive layer 12 may be bonded to one surface (here, the first surface 11a) of the substrate 11 to laminate the adhesive layer 12 on the substrate 11. In this case, the release film may be removed at any time during the manufacturing process or the use process of the composite sheet 101.

When the adhesive layer 12 is energy ray curable, examples of the energy ray curable adhesive composition include an adhesive composition (I-1) containing a non-energy ray curable adhesive resin (I-1a) (hereinafter sometimes abbreviated as "adhesive resin (I-1a)") and an energy ray curable compound; an adhesive composition (I-2) containing an energy ray curable adhesive resin (I-2a) (hereinafter sometimes abbreviated as "adhesive resin (I-2a)") in which an unsaturated group has been introduced into the side chain of the adhesive resin (I-1a); an adhesive composition (I-3) containing the adhesive resin (I-2a) and an energy ray curable compound, and the like.

When the adhesive layer 12 is non-energy ray curable, examples of non-energy ray curable adhesive compositions include adhesive composition (I-4) containing the adhesive resin (I-1a).

The film-like adhesive 13 has the above-mentioned light transmittance. For example, at least one of the first surface 13a and the second surface 13b of the film-like adhesive 13 is substantially free of aromatic compounds.
The thickness of the film adhesive 13 is preferably 10 to 40 μm.
The film-like adhesive 13 can be formed using the adhesive composition described above.

The release film 15 is similar to the first release film 151 or the second release film 152 shown in Figure 1.

Not only in the case of the composite sheet 101, but in the composite sheet of this embodiment, the release film (e.g., release film 15 shown in Figure 3) is of any configuration, and the composite sheet of this embodiment may or may not include a release film.

The composite sheet 101 is used by removing the release film 15 and attaching an object (e.g., the circuit formation surface of a chip) to the first surface 13a of the film-like adhesive 13.

The composite sheet of this embodiment is not limited to the one shown in Figure 3, and may have some of the configurations shown in Figure 3 changed or removed, or may have other configurations added to those described above, as long as the effects of the present invention are not impaired. More specifically, it is as follows.

So far, the composite sheet has been described as having a dicing sheet formed by laminating a substrate and an adhesive layer, but the composite sheet of this embodiment may also have a dicing sheet formed only of a substrate. That is, the composite sheet may be configured to have a substrate and a film-like adhesive provided on one side of the substrate, without an adhesive layer being disposed between the substrate and the film-like adhesive. An example of such a composite sheet is a laminated sheet 108 shown in FIG. 2 in which the resin film 19 is the substrate (for example, substrate 11 shown in FIG. 3).

So far, a composite sheet including a dicing sheet formed by laminating a substrate and an adhesive layer has been described, but the composite sheet of this embodiment may also include a dicing sheet including an intermediate layer in addition to the substrate and adhesive layer. Such a dicing sheet may include, for example, a substrate, an adhesive layer provided on one side of the substrate, and an intermediate layer provided on the surface of the adhesive layer opposite the substrate side. When such a dicing sheet is used, an intermediate layer is disposed between the adhesive layer and the film-like adhesive in the composite sheet.

For example, the composite sheet of this embodiment may have only the release film on the first surface of the film-like adhesive, but may also have a jig adhesive layer in the area near the peripheral edge of the first surface of the film-like adhesive for fixing the composite sheet to a jig such as a ring frame.
The jig adhesive layer in this case is the same as that described above.

For example, when the composite sheet is viewed in plan from above the film-like adhesive side or the dicing sheet side, the surface areas of the film-like adhesive and the dicing sheet may be equal or nearly equal, but in the composite sheet of this embodiment, the surface area of the film-like adhesive may be smaller than the surface area of the dicing sheet, and a portion of the dicing sheet (e.g., the pressure-sensitive adhesive layer) may be exposed. In that case, for example, at least the peripheral portion in the width direction of the dicing sheet may be exposed without being covered with the film-like adhesive. Such a composite sheet may have the above-mentioned jig adhesive layer on the exposed surface of the dicing sheet.

Up to this point, the composite sheet has been made up of a substrate, a pressure-sensitive adhesive layer, an intermediate layer, a film-like adhesive, a jig adhesive layer, and a release film, but the composite sheet of this embodiment may also have other layers that do not fall into any of these categories.
When the composite sheet includes the other layer, the position of the other layer is not particularly limited.

In the composite sheet of this embodiment, the size and shape of each layer can be selected arbitrarily depending on the purpose.

◇How to use the laminated sheet (film-like adhesive) <<Laminate and its manufacturing method>>
The film-like adhesive in the laminate sheet of this embodiment can be used, for example, as a film for adhering a light-transmitting cover to the circuit-forming surface of a chip such as a sensor.
More specifically, by using the film-like adhesive, a laminate can be manufactured that includes a chip, a film-like adhesive provided on the circuit-forming surface of the chip, and a light-transmitting cover provided on the surface of the film-like adhesive opposite to the chip side. In the laminate, it is preferable that either or both of the surface of the film-like adhesive on the chip side and the surface on the light-transmitting cover side are substantially free of aromatic compounds, and both are substantially free of aromatic compounds.

FIG. 4 is a cross-sectional view illustrating an example of the laminate.
The laminate 801 shown here is composed of a chip 8, a film-like adhesive 13 provided on the circuit forming surface 8a of the chip 8, and a light-transmitting cover 7 provided on the surface (first surface) 13a of the film-like adhesive 13 opposite the chip 8 side.

In the laminate 801, the opposing surfaces of the chip 8 and the film-like adhesive 13, i.e., the circuit formation surface 8a of the chip 8 and the surface (second surface) 13b of the film-like adhesive 13 on the chip 8 side, are in direct contact. Also, the opposing surfaces of the film-like adhesive 13 and the light-transmitting cover 7, i.e., the first surface 13a of the film-like adhesive 13 and the surface (sometimes referred to as the "second surface" in this specification) 7b of the light-transmitting cover 7 on the film-like adhesive 13 side, are in direct contact.
In this way, the laminate 801 is constructed by stacking the chip 8, the film-like adhesive 13, and the light-transmitting cover 7 in this order in the thickness direction, with the circuit forming surface 8a of the chip 8 being positioned on the film-like adhesive 13 side.

The film-like adhesive 13 in the laminate 801 is, for example, the laminate sheet 109 shown in Figure 1 from which the first release film 151 and the second release film 152 have been removed, or the laminate sheet 108 shown in Figure 2 from which the resin film 19 has been removed.
In the laminate 801, either or both of the first surface 13a and the second surface 13b of the film-like adhesive 13 are preferably substantially free of aromatic compounds, and both are preferably substantially free of aromatic compounds.

In addition, in Figure 4, the circuit of chip 8 is omitted. Also, symbol 7a indicates the surface opposite to the second surface 7b of the light-transmitting cover 7 (sometimes referred to as the "first surface" in this specification).

The light-transmitting cover 7 protects the circuit-forming surface 8a of the chip 8, and also allows the outside of the second surface 7b side to be viewed from the outside of the first surface 7a side.
On the other hand, the film-like adhesive 13 has the above-mentioned light transparency. Therefore, in the laminate 801, visual information present on the circuit formation surface 8a of the chip 8 can be visually recognized through the light-transmitting cover 7 and the film-like adhesive 13 (through the light-transmitting cover 7 and the film-like adhesive 13).
Furthermore, as described above, the film adhesive 13 has high light transmittance and is suppressed from coloring before and after heating. Therefore, the laminate 801 allows visual recognition of the visual information on the chip 8 with a stable and high degree of accuracy.

The chip 8 can be, for example, a fingerprint sensor, in which case the laminate 801 can be used as a fingerprint sensor module.

The laminate using the film-like adhesive is not limited to that shown in Figure 4, and may have some of the configuration shown in Figure 4 modified or removed, or may have other configurations added to those described so far, as long as the effects of the present invention are not impaired.

The laminate can be manufactured, for example, by bonding the circuit formation surface of a chip to one side (second side) of the film-like adhesive and bonding a light-transmitting cover to the other side (first side) of the film-like adhesive.

◇How to use the composite sheet <<Laminate and its manufacturing method>>
The composite sheet of this embodiment can be used in the same manner as known composite sheets.
5 is a cross-sectional view for explaining an example of a method of using the composite sheet of the present embodiment, in which the composite sheet 101 shown in FIG.

As shown here, the composite sheet 101 is used by removing the release film 15 and then attaching the first surface 13a of the film-like adhesive 13 to the circuit formation surface 8a of the chip 8.

After the composite sheet 101 is attached to the chip 8, for example, the chip 8 is diced into individual pieces, and the film-like adhesive 13 is cut along the outer periphery of the individual chip 8. At this time, the individualization of the chip 8 and the cutting of the film-like adhesive 13 can be performed by a known method. For example, these may be performed simultaneously, or the chip 8 may be individualized and then the film-like adhesive 13 may be cut separately.

Next, the individual chips 8 are picked up together with the cut film-like adhesive 13 by separating them from the dicing sheet 10. If the adhesive layer 12 is energy ray curable, the adhesive layer 12 is energy ray cured to reduce the adhesive strength to the film-like adhesive 13 before picking up, which makes picking up easier.

Next, a light-transmitting cover is attached to the second surface of the film-like adhesive 13 after cutting and picking up, thereby producing the laminate (for example, the laminate 801 shown in FIG. 4).
In the laminate, either or both of the first and second surfaces of the film-like adhesive are preferably substantially free of aromatic compounds, and both are preferably substantially free of aromatic compounds.

Here, the film-like adhesive in the composite sheet is attached to the chip, and after the chip is divided and the film-like adhesive is cut, the light-transmitting cover is attached to the cut film-like adhesive. However, the order of attaching the chip and the light-transmitting cover to the film-like adhesive may be reversed. That is, the first surface of the film-like adhesive is attached to the second surface of the light-transmitting cover, the light-transmitting cover is diced into individual pieces, the film-like adhesive is cut, and the adhesive layer is cured with energy rays as necessary. The light-transmitting cover after division is separated from the dicing sheet together with the cut film-like adhesive and picked up, and then the chip is attached to the first surface of the cut and picked-up film-like adhesive, thereby manufacturing the laminate (for example, the laminate 801 shown in FIG. 4).

The present invention will be described in more detail below with reference to specific examples. However, the present invention is not limited to the examples shown below.

<Materials for producing adhesive composition>
In the present examples and comparative examples, the raw materials used in producing the adhesive compositions are shown below.

[Acrylic resin (a)]
(a)-1: An acrylic resin (weight average molecular weight 800,000, glass transition temperature 6° C.) obtained by copolymerizing methyl acrylate (85 parts by mass) and 2-hydroxyethyl acrylate (15 parts by mass).
(a)-2: An acrylic resin (weight average molecular weight 800,000, glass transition temperature 9° C.) obtained by copolymerizing methyl acrylate (95 parts by mass) and 2-hydroxyethyl acrylate (5 parts by mass).
[Epoxy compound (b1)]
(b1)-1: cresol novolac type epoxy resin having an acryloyl group added thereto ("CNA147" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 518 g/eq, number average molecular weight: 2100, the content of unsaturated groups and the content of epoxy groups are equal)
(b1)-2: Hydrogenated bisphenol A type epoxy resin ("Epolite 4000" manufactured by Kyoeisha Chemical Co., Ltd., epoxy equivalent: 310 to 340 g/eq)
(b1)-3: Hydrogenated bisphenol type epoxy resin ("YX8000" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 205 g/eq)
(b1)-4: Triazine-type alicyclic epoxy compound ("TEPIC-PAS B22" manufactured by Nissan Chemical Industries, Ltd., epoxy equivalent: 180 to 200 g/eq)
(b1)-5: Triazine-type alicyclic epoxy compound ("TEPIC VL" manufactured by Nissan Chemical Industries, Ltd., epoxy equivalent: 125 to 145 g/eq)
(b1)-6: Bisphenol A type epoxy resin ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 184 to 194 g/eq)
(b1)-7: Dicyclopentadiene type epoxy resin ("XD-1000-L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 248 g/eq)
(b1)-8: Triphenylene type epoxy resin ("EPPN-502H" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 158 to 178 g/eq)
[Phenol resin (b2)]
(b2)-1: Aralkyl-type phenolic resin ("HE100C-10" manufactured by Air Water Chemical Co., Ltd.)
[Filler (d)]
(d)-1: Spherical silica modified with methacrylic groups ("YA050C-MJE" manufactured by Admatechs Co., Ltd., average particle size 50 nm)
(d)-2: Spherical silica modified with epoxy groups ("YA050C-MKK" manufactured by Admatechs Co., Ltd., average particle size 50 nm)
[Crosslinking agent (f)]
(f)-1: Tolylene diisocyanate trimer adduct of trimethylolpropane ("Coronate L" manufactured by Tosoh Corporation)
(f)-2: Isophorone diisocyanate trimer adduct of trimethylolpropane ("D-140N" manufactured by Mitsui Chemicals, Inc.)
(f)-3: xylylene diisocyanate trimer adduct of trimethylolpropane ("D-110N" manufactured by Mitsui Chemicals, Inc.)
(f)-4: Hexamethylene diisocyanate trimer adduct of trimethylolpropane ("Bxx4773" manufactured by Toyochem Co., Ltd.)
[Phosphorus-based antioxidant (z)]
(z)-1: Bis(decyl)pentaerythritol diphosphite ("JPE-10" manufactured by Johoku Chemical Industry Co., Ltd., an aliphatic phosphite ester)
(z)-2: Tris(2-ethylhexyl)phosphite ("JP-308E" manufactured by Johoku Chemical Industry Co., Ltd., an aliphatic phosphite ester)

[Example 1]
<<Production of Film-like Adhesive>>
<Production of Adhesive Composition>
An adhesive composition having a total concentration of all components other than methyl ethyl ketone of 32% by mass was obtained by dissolving or dispersing acrylic resin (a)-1 (44.3 parts by mass), epoxy compound (b1)-2 (40 parts by mass), filler (d)-2 (15 parts by mass), crosslinker (f)-4 (0.2 parts by mass) and phosphorus-based antioxidant (z)-1 (0.5 parts by mass) in methyl ethyl ketone and stirring at 23° C. Note that the amounts of all components other than methyl ethyl ketone shown here are the amounts of the target product not including the solvent component.

<Production of Film Adhesive>
A release film ("SP-PET381031", manufactured by Lintec Corporation, thickness 38 μm) made of polyethylene terephthalate (PET) film, one side of which had been treated for release by silicone treatment, was used, and the adhesive composition obtained above was applied to the release-treated surface, followed by heating and drying at 100° C. for 2 minutes to form a film-like adhesive with a thickness of 20 μm, and an adhesive sheet was obtained in which the release film and the film-like adhesive were laminated in the thickness direction.

<<Evaluation of film adhesive>>
<Measurement of shear strength>
Using a tape mounter ("Adwill RAD2500 m/12" manufactured by Lintec Corporation), a dicing sheet ("Adwill D-678" manufactured by Lintec Corporation) was attached to a 6-inch silicon wafer (thickness: 350 μm) at an attachment temperature of 23° C. and an attachment speed of 20 mm/s, and the laminate of the dicing sheet and silicon wafer was fixed to a ring frame.
Next, dicing was performed using a dicing device (DISCO Corp., "DFD6362") and a dicing blade (DISCO Corp., "NBC-ZH2050-SE27HECC") under conditions of a blade rotation speed of 30,000 rpm and a cutting speed of 40 mm/s, to obtain multiple silicon chips (hereinafter sometimes referred to as "silicon chip group") measuring 2 mm x 2 mm. The dicing sheet is constructed by laminating a base material and an adhesive layer, and during dicing, the dicing blade cut into the base material in the dicing sheet to a depth of 20 μm.

Next, the adhesive sheet obtained above was attached to the group of silicon chips obtained above using the film-like adhesive therein while being heated to 60° C. At this time, the adhesive sheet was attached to the surface (exposed surface) of each silicon chip in the group of silicon chips opposite to the side to which the dicing sheet was attached. Then, the attached adhesive sheet was cut along the periphery of the silicon chip.
As a result of the above, a laminate having a size of 2 mm x 2 mm was obtained, in which the dicing sheet, silicon chip, and adhesive sheet were laminated in this order in the thickness direction.

Next, the release film was removed from the film-like adhesive in the laminate, and the newly exposed surface of the film-like adhesive was attached to the surface of a copper plate measuring 30 mm x 30 mm and 300 μm thick using a manual die bonder. The film-like adhesive was attached by pressing it against the copper plate with a force of 2.45 N (250 gf) while heating it to 125°C. The laminate was then heated at 175°C for 5 hours to obtain a test specimen.

Next, using a universal bond tester (Nordson Advanced Technologies' "DAGE4000"), a force was applied to both the film adhesive and the silicon chip on the side of the test piece in a direction parallel to the surface of the film adhesive attached to the copper plate at a speed of 200 μm/s using a shear tool at a temperature of 23°C. The maximum force applied until the film adhesive was broken was then confirmed, and this was used as the shear strength of the film adhesive (N/2 mm□). The results are shown in Table 1.

<Measurement of linear transmittance of light (400 to 800 nm) before heating>
The film-like adhesive obtained above was attached to one side of a glass preparation (thickness: 0.9 mm) while being heated at 40° C. The film-like adhesive was not subjected to a heat treatment immediately after its production until this attachment.
Next, the portion of the film-like adhesive that had been applied and was protruding from the glass preparation was cut off, and a test piece (hereinafter referred to as the "pre-heated test piece") was obtained in which the film-like adhesive and the glass preparation of the same size were laminated in the thickness direction with the positions of their peripheral edges aligned.

For the glass preparation used to prepare the pre-heated test specimen, the linear transmittance (hereinafter referred to as the "reference linear transmittance") of light (400 to 800 nm) was measured using a spectrophotometer (Shimadzu Corporation, "UV-3101PC") before preparing the pre-heated test specimen.
The linear transmittance of light (400 to 800 nm) of the pre-heated test piece obtained above was also measured by the same method.
The value obtained by subtracting the measured value of the reference linear transmittance at each wavelength (400 to 800 nm) from the measured value of the linear transmittance at the same wavelength of the test piece before heating was adopted as the linear transmittance of light (400 to 800 nm) of the film-like adhesive before heating (i.e., the linear transmittance before heating). The results are shown in Table 1.

<Measurement of linear transmittance of light (400 to 800 nm) after heating>
The test piece after measuring the linear transmittance of the above light (400 to 800 nm) before heating was heated at 260° C. for 10 minutes using an electric furnace.
Next, the heated test piece was allowed to cool to the same temperature as room temperature.
Next, the linear transmittance of light (400 to 800 nm) of the test piece after heating and cooling (hereinafter referred to as the "heated test piece") was measured in the same manner as in the case of the above-mentioned unheated test piece.
The measured linear transmittance of the test piece at each wavelength (400 to 800 nm) after heating was subtracted from the measured linear transmittance of the test piece at the same wavelength to obtain the reference linear transmittance at the same wavelength. The obtained value was used as the linear transmittance of the film-like adhesive at 400 to 800 nm after heating (i.e., the linear transmittance after heating). The results are shown in Table 1.

<Evaluation of fingerprint recognition before heating using RGB>
A digital camera (Canon IXY650) was placed in front of the pad of the left index finger, and the distance between the surface of the pad of the left index finger and the surface of the camera lens was adjusted to 50 mm. In this state, image data of the fingerprint of the left index finger (hereinafter referred to as "reference image data") was obtained in macro mode.
While maintaining the positional relationship between the index finger of the left hand and the digital camera, the pre-heated test piece was further placed between the pad of the index finger of the left hand and the digital camera. At this time, the pre-heated test piece was placed so that the straight line connecting the pad of the index finger of the left hand and the digital camera was perpendicular to the exposed surface of the glass preparation in the pre-heated test piece (i.e., the surface opposite to the surface attached to the film-like adhesive), and the exposed surface was on the digital camera side. Under these conditions, the image data of the fingerprint of the index finger of the left hand (hereinafter referred to as "pre-heated transmission image data") was obtained in macro mode in the same manner as when the reference image data was obtained.

Using graphics software (Microsoft Paint), the reference imaging data and pre-heating transmission imaging data obtained above were developed, and the colors of the fingerprint peaks and valleys were extracted from each data and quantified in RGB.
The value obtained by subtracting the R value of the fingerprint ridges obtained from the reference imaging data from the R value of the fingerprint ridges obtained from the pre-heating transmission imaging data was adopted as the R value of the fingerprint ridges in the pre-heating evaluation. In a similar manner, the G value and B value of the fingerprint ridges in the pre-heating evaluation were obtained.
In the same manner as above, the R value of the fingerprint valley obtained from the reference imaging data was subtracted from the R value of the fingerprint valley obtained from the pre-heating transmission imaging data, and the obtained value was adopted as the R value of the fingerprint valley during the pre-heating evaluation. In the same manner, the G value and B value of the fingerprint valley during the pre-heating evaluation were obtained.
Furthermore, the absolute value of the difference between the R value of the peaks and the R value of the valleys (hereinafter may be referred to as "absolute value ΔR") was calculated, the absolute value of the difference between the G value of the peaks and the G value of the valleys (hereinafter may be referred to as "absolute value ΔG") was calculated, and the absolute value of the difference between the B value of the peaks and the B value of the valleys (hereinafter may be referred to as "absolute value ΔB") was calculated.

Based on these calculated values, the fingerprint recognizability of the film-like adhesive before heating was evaluated by RGB according to the following criteria. The results are shown in Table 1.
(Evaluation criteria)
A: At least one of the absolute value ΔR, the absolute value ΔG, and the absolute value ΔB is 10 or more.
B: The absolute value ΔR, the absolute value ΔG, and the absolute value ΔB are all less than 10, and at least one of the absolute value ΔR, the absolute value ΔG, and the absolute value ΔB is 5 or greater.
C: The absolute value ΔR, the absolute value ΔG and the absolute value ΔB are all less than 5.

<Evaluation of fingerprint recognition after heating using RGB>
The fingerprint recognizability of the film-like adhesive after heating was evaluated using RGB in the same manner as in the above-mentioned "Evaluation of fingerprint recognizability before heating" except that the heated test piece was used instead of the heated test piece.
More specifically, in this evaluation, "post-heating transmission imaging data" was obtained instead of the pre-heating transmission imaging data. In addition, using this post-heating transmission imaging data, instead of the R value, G value, and B value of the fingerprint ridges in the pre-heating evaluation, the R value, G value, and B value of the fingerprint ridges in the post-heating evaluation were obtained, and instead of the R value, G value, and B value of the fingerprint valleys in the pre-heating evaluation, the R value, G value, and B value of the fingerprint valleys in the post-heating evaluation were obtained. Furthermore, from these R value, G value, and B value, instead of the absolute value ΔR, absolute value ΔG, and absolute value ΔB in the pre-heating evaluation, the absolute value ΔR, absolute value ΔG, and absolute value ΔB in the post-heating evaluation were calculated. The results are shown in Table 1.

<Visual evaluation of fingerprint recognition before heating>
Five observers were randomly selected, and each observer visually inspected the fingerprints using the method described below.
That is, an observer was placed in front of the pad of the left index finger, and the distance between the surface of the pad of the left index finger and the observer's eye was adjusted to 150 mm. In this state, the fingerprint on the left index finger was directly and visually observed.
While maintaining the positional relationship between the index finger of the left hand and the observer, the pre-heated test piece was further placed between the pad of the index finger of the left hand and the observer. The positional form of the pre-heated test piece at this time was the same as that of the pre-heated test piece in the above-mentioned "Evaluation of fingerprint recognition property before heating by RGB". Under this condition, the fingerprint of the left index finger was visually observed through the pre-heated test piece in the same manner as in the case of direct visual observation as described above.

Using this method, all five observers visually observed the fingerprints both directly and through the pre-heated test piece, and evaluated the fingerprint recognizability of the film-like adhesive before heating by visual observation according to the following criteria by comparing the visibility of the fingerprints through the pre-heated test piece with the visibility of the fingerprints when observed directly. The results are shown in Table 1. The number in parentheses in the "Fingerprint recognizability" column in Table 1 indicates the "number of observers who judged that there was no difference in the visibility of the fingerprints (people)."
A: All five observers judged that there was no difference in how the fingerprints appeared.
B: Four out of five observers judged that there was no difference in the appearance of the fingerprints.
C: Two or more of the five observers judged that the colors of the fingerprints were different from one another and that there was a difference in how they appeared.

<Visual evaluation of fingerprint recognition after heating>
Except for using the heated test pieces instead of the pre-heated test pieces, the fingerprint recognizability of the film-like adhesive after heating was evaluated visually in the same manner as in the above-mentioned "Visual evaluation of fingerprint recognizability before heating". The results are shown in Table 1.

<Evaluation of the presence or absence of aromatic compounds by FT-IR>
Using a Fourier transform infrared/near-far infrared spectrometer (PerkinElmer's Spectrum 100), FT-IR measurement was performed on one side of the film-like adhesive obtained above by the ATR method in the wavenumber range of 4000 to 400 cm ^-1 . The presence or absence of an inflection point in the curve showing transmittance in the wavenumber range of 3050 to 2990 cm ^-1 was confirmed to confirm the presence or absence of aromatic compounds on said side of the film-like adhesive. The results are shown in Table 1. In the column "FT-IR (3050-2990 cm ^-1 ) inflection point" in Table 1, the number in parentheses for "present" indicates the "wavenumber (cm ^-1 ) at which the inflection point was observed." The spectrum data obtained at this time is shown in FIG. 6.

<<Production and Evaluation of Film Adhesive>>
[Examples 2 to 4]
Film-like adhesives were produced and evaluated in the same manner as in Example 1, except that either or both of the types and amounts of the components blended during the production of the adhesive composition were changed so that the types and contents of the components contained in the adhesive composition were as shown in Table 1. The results are shown in Table 1.

[Comparative Examples 1 to 3]
An attempt was made to produce and evaluate a film-like adhesive in the same manner as in Example 1, except that either or both of the types and amounts of the components blended during the production of the adhesive composition were changed so that the types and contents of the components contained in the adhesive composition were as shown in Table 2. The results are shown in Table 2.

In addition, a "-" in the component column in Tables 1 and 2 means that the adhesive composition does not contain that component.

As is clear from the above results, in Examples 1 to 4, the film-like adhesive before and after heating at 260°C had high light transmittance, suppressed coloring, and high fingerprint recognition ability. In Examples 1 to 4, the linear transmittance of light (400 to 800 nm) of the film-like adhesive before heating at 260°C was 95% or more (95 to 98%), and the linear transmittance of light (400 to 800 nm) of the film-like adhesive after heating at 260°C was 86% or more (86 to 95%).

In Examples 1 to 4, the shear strength of the film-like adhesive was 48 N/2 mm square or more (48 to 80 N/2 mm square), and the adhesive strength of the film-like adhesive was sufficiently strong.

In Examples 1 to 4, the film-like adhesive contained a phosphorus-based antioxidant (z), and further, all of the components, including this phosphorus-based antioxidant (z), did not have an aromatic cyclic group, which is presumably why discoloration due to heating was suppressed.
In Examples 1 to 4, no clear inflection points that could not be considered noise were observed in the transmittance curve in the wavenumber range of 3050 to 2990 cm ^-1 , indicating that aromatic compounds were substantially absent from the measurement surface of the film-like adhesive, a result consistent with the use of the above-mentioned components. In order to make the transmittance curve easier to see, the results for Examples 3 and 4 are not shown in Figure 6, but the curves for Examples 3 and 4 had the same shape as the curves for Examples 1 and 2.

In contrast, in Comparative Examples 1 to 3, the film-like adhesive after heating at 260°C had low light transmittance, coloring was not suppressed, and fingerprint recognition was poor. In Comparative Examples 1 to 3, the linear transmittance of light (400 to 800 nm) of the film-like adhesive after heating at 260°C was 16% or less.

In Comparative Examples 1 and 3, although the film adhesive contained a phosphorus-based antioxidant (z), the epoxy compound (b1), the phenolic resin (b2), and the crosslinking agent (f) all had aromatic cyclic groups, so it was presumed that coloring due to heating was not suppressed. As is clear from FIG. 5, in Comparative Examples 1 and 3, a clear inflection point that cannot be said to be noise was observed in the transmittance curve in the wave number range of 3050 to 2990 cm ^-1 , indicating the presence of aromatic compounds on the measurement surface of the film adhesive. This result was consistent with the use of the above-mentioned components.

In Comparative Example 2, the film-like adhesive before heating at 260°C had high light transmittance and was inhibited from coloring, but did not contain any antioxidants, including the phosphorus-based antioxidant (z), and the epoxy compound (b1), phenolic resin (b2), and crosslinking agent (f) all had aromatic cyclic groups, so it was presumed that coloring due to heating was not inhibited. As is clear from Figure 5, in Comparative Example 2, a clear inflection point was observed in the curve showing the transmittance in the wavenumber range of 3050 to 2990 cm ^-1 , indicating the presence of aromatic compounds on the measurement surface of the film-like adhesive. This result was consistent with the use of the above-mentioned components.

Furthermore, in Comparative Example 2, the shear strength of the film-like adhesive was 45 N/2 mm□, and the adhesive strength of the film-like adhesive was weaker than in Examples 1 to 4.

The present invention can be used as an adhesive during the manufacturing or processing of various components that make up electronic devices.

101: Composite sheet, 108, 109: Laminated sheet, 10: Dicing sheet, 11: Substrate, 11a: First surface of substrate, 12: Adhesive layer, 13: Film-like adhesive, 13a: First surface of film-like adhesive, 13b: Second surface of film-like adhesive, 151: First release film, 152: Second release film, 19: Resin film, 7: Light-transmitting cover, 8: Chip, 8a: Circuit formation surface of chip, 801: Laminate

Claims (8)

A film-like adhesive for bonding a circuit-forming surface of a chip to a light-transmitting cover,
A film-like adhesive, at least one surface of which is substantially free of aromatic compounds (excluding those containing a polymer having organopolysiloxane in the side chain) . the linear transmittance of the film-like adhesive before heating at 260° C. to light having a wavelength of 400 to 800 nm is 90% or more;
the film-like adhesive after heating at 260° C. for 10 minutes has an in-line transmittance of 85% or more for light having a wavelength of 400 to 800 nm;
2. The film-like adhesive according to claim 1, wherein the thickness of the film-like adhesive is 10 to 40 μm. The film-like adhesive according to claim 1 or 2, wherein the film-like adhesive contains an aliphatic epoxy compound. The film adhesive according to any one of claims 1 to 3, wherein the film adhesive contains an aliphatic phosphite ester as an antioxidant. The film-like adhesive contains an acrylic resin and an aliphatic polyisocyanate crosslinking agent,
The film-like adhesive according to any one of claims 1 to 4, wherein the acrylic resin has a functional group capable of bonding with the aliphatic polyvalent isocyanate crosslinking agent. A laminated sheet comprising the film-like adhesive according to any one of claims 1 to 5 and a resin film provided on one side of the film-like adhesive. The adhesive film according to any one of claims 1 to 5 and a dicing sheet provided on one surface of the adhesive film,
The dicing sheet includes a base material and a pressure-sensitive adhesive layer provided on one surface of the base material,
A composite sheet, wherein the pressure-sensitive adhesive layer is disposed between the substrate and the film-like adhesive. A method for manufacturing a laminate, comprising laminating a circuit-forming surface of a chip to one side of the film-like adhesive described in any one of claims 1 to 5, and laminating a light-transmitting cover to the other side of the film-like adhesive, thereby obtaining a laminate in which the chip, the film-like adhesive, and the light-transmitting cover are laminated in this order.

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